1
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Edwards DN, Wang S, Song W, Kim LC, Ngwa VM, Hwang Y, Ess KC, Boothby MR, Chen J. Regulation of fatty acid delivery to metastases by tumor endothelium. bioRxiv 2024:2024.04.02.587724. [PMID: 38617241 PMCID: PMC11014634 DOI: 10.1101/2024.04.02.587724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Tumor metastasis, the main cause of death in cancer patients, requires outgrowth of tumor cells after their dissemination and residence in microscopic niches. Nutrient sufficiency is a determinant of such outgrowth1. Fatty acids (FA) can be metabolized by cancer cells for their energetic and anabolic needs but impair the cytotoxicity of T cells in the tumor microenvironment (TME)2,3, thereby supporting metastatic progression. However, despite the important role of FA in metastatic outgrowth, the regulation of intratumoral FA is poorly understood. In this report, we show that tumor endothelium actively promotes tumor growth and restricts anti-tumor cytolysis by transferring FA into developing metastatic tumors. This process uses transendothelial fatty acid transport via endosome cargo trafficking in a mechanism that requires mTORC1 activity. Thus, tumor burden was significantly reduced upon endothelial-specific targeted deletion of Raptor, a unique component of the mTORC1 complex (RptorECKO). In vivo trafficking of a fluorescent palmitic acid analog to tumor cells and T cells was reduced in RptorECKO lung metastatic tumors, which correlated with improved markers of T cell cytotoxicity. Combination of anti-PD1 with RAD001/everolimus, at a low dose that selectively inhibits mTORC1 in endothelial cells4, impaired FA uptake in T cells and reduced metastatic disease, corresponding to improved anti-tumor immunity. These findings describe a novel mechanism of transendothelial fatty acid transfer into the TME during metastatic outgrowth and highlight a target for future development of therapeutic strategies.
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Affiliation(s)
- Deanna N. Edwards
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
- Vanderbilt-Ingram Cancer Center, Nashville, TN, USA
| | - Shan Wang
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
| | - Wenqiang Song
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
- Vanderbilt University Medical Center, Department of Medicine, Division of Epidemiology, Nashville, TN, USA
- Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, Nashville, TN, USA
| | - Laura C. Kim
- Vanderbilt University, Program in Cancer Biology, Nashville, TN, USA
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Verra M. Ngwa
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
| | - Yoonha Hwang
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
| | - Kevin C. Ess
- University of Colorado Anschutz Medical Campus, Department of Pediatrics, Denver, CO, USA
- Vanderbilt University Medical Center, Department of Pediatrics, Nashville, TN, USA
| | - Mark R. Boothby
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
- Vanderbilt University Medical Center, Department of Pathology, Microbiology and Immunology, Nashville, TN, USA
- Vanderbilt University, Program in Cancer Biology, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN, USA
| | - Jin Chen
- Vanderbilt University Medical Center, Department of Medicine, Division of Rheumatology and Immunology, Nashville, TN, USA
- Vanderbilt-Ingram Cancer Center, Nashville, TN, USA
- Vanderbilt University, Program in Cancer Biology, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN, USA
- Vanderbilt University, Department of Cell and Developmental Biology, Nashville, TN, USA
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, TN, USA
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2
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Sidorov VY, Sidorova TN, Samson PC, Reiserer RS, Britt CM, Neely MD, Ess KC, Wikswo JP. Contractile and Genetic Characterization of Cardiac Constructs Engineered from Human Induced Pluripotent Stem Cells: Modeling of Tuberous Sclerosis Complex and the Effects of Rapamycin. Bioengineering (Basel) 2024; 11:234. [PMID: 38534508 DOI: 10.3390/bioengineering11030234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/21/2024] [Accepted: 02/23/2024] [Indexed: 03/28/2024] Open
Abstract
The implementation of three-dimensional tissue engineering concurrently with stem cell technology holds great promise for in vitro research in pharmacology and toxicology and modeling cardiac diseases, particularly for rare genetic and pediatric diseases for which animal models, immortal cell lines, and biopsy samples are unavailable. It also allows for a rapid assessment of phenotype-genotype relationships and tissue response to pharmacological manipulation. Mutations in the TSC1 and TSC2 genes lead to dysfunctional mTOR signaling and cause tuberous sclerosis complex (TSC), a genetic disorder that affects multiple organ systems, principally the brain, heart, skin, and kidneys. Here we differentiated healthy (CC3) and tuberous sclerosis (TSP8-15) human induced pluripotent stem cells (hiPSCs) into cardiomyocytes to create engineered cardiac tissue constructs (ECTCs). We investigated and compared their mechano-elastic properties and gene expression and assessed the effects of rapamycin, a potent inhibitor of the mechanistic target of rapamycin (mTOR). The TSP8-15 ECTCs had increased chronotropy compared to healthy ECTCs. Rapamycin induced positive inotropic and chronotropic effects (i.e., increased contractility and beating frequency, respectively) in the CC3 ECTCs but did not cause significant changes in the TSP8-15 ECTCs. A differential gene expression analysis revealed 926 up- and 439 down-regulated genes in the TSP8-15 ECTCs compared to their healthy counterparts. The application of rapamycin initiated the differential expression of 101 and 31 genes in the CC3 and TSP8-15 ECTCs, respectively. A gene ontology analysis showed that in the CC3 ECTCs, the positive inotropic and chronotropic effects of rapamycin correlated with positively regulated biological processes, which were primarily related to the metabolism of lipids and fatty and amino acids, and with negatively regulated processes, which were predominantly associated with cell proliferation and muscle and tissue development. In conclusion, this study describes for the first time an in vitro TSC cardiac tissue model, illustrates the response of normal and TSC ECTCs to rapamycin, and provides new insights into the mechanisms of TSC.
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Affiliation(s)
- Veniamin Y Sidorov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Tatiana N Sidorova
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Philip C Samson
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
| | - Ronald S Reiserer
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
| | - Clayton M Britt
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
| | - M Diana Neely
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - John P Wikswo
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37212, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
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3
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Brown JA, Faley SL, Judge M, Ward P, Ihrie RA, Carson R, Armstrong L, Sahin M, Wikswo JP, Ess KC, Neely MD. Rescue of Impaired Blood-Brain Barrier in Tuberous Sclerosis Complex Patient Derived Neurovascular Unit. bioRxiv 2023:2023.12.15.571738. [PMID: 38168450 PMCID: PMC10760190 DOI: 10.1101/2023.12.15.571738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Tuberous sclerosis complex (TSC) is a multi-system genetic disease that causes benign tumors in the brain and other vital organs. The most debilitating symptoms result from involvement of the central nervous system and lead to a multitude of severe symptoms including seizures, intellectual disability, autism, and behavioral problems. TSC is caused by heterozygous mutations of either the TSC1 or TSC2 gene. Dysregulation of mTOR kinase with its multifaceted downstream signaling alterations is central to disease pathogenesis. Although the neurological sequelae of the disease are well established, little is known about how these mutations might affect cellular components and the function of the blood-brain barrier (BBB). We generated disease-specific cell models of the BBB by leveraging human induced pluripotent stem cell and microfluidic cell culture technologies. Using these microphysiological systems, we demonstrate that the BBB generated from TSC2 heterozygous mutant cells shows increased permeability which can be rescued by wild type astrocytes and with treatment with rapamycin, an mTOR kinase inhibitor. Our results further demonstrate the utility of microphysiological systems to study human neurological disorders and advance our knowledge of the cell lineages contributing to TSC pathogenesis.
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Affiliation(s)
- Jacquelyn A Brown
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Shannon L Faley
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Monika Judge
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Patricia Ward
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
| | - Rebecca A Ihrie
- Dept. of Cell & Developmental Biology, Vanderbilt University
- Neurological Surgery, Vanderbilt University Medical Center
| | - Robert Carson
- Dept. of Pediatrics, Vanderbilt University Medical Center
| | | | - Mustafa Sahin
- Rosamund Stone Translational Neuroscience Center, Dept. of Neurology, Boston Children's Hospital, Harvard Medical School
| | - John P Wikswo
- Dept. of Physics and Astronomy, Vanderbilt University
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University
- Dept. of Biomedical Engineering, Vanderbilt University
- Dept. of Molecular Physiology and Biophysics, Vanderbilt University
| | - Kevin C Ess
- Neurological Surgery, Vanderbilt University Medical Center
- Dept. of Pediatrics, Vanderbilt University Medical Center
| | - M Diana Neely
- Dept. of Pediatrics, Vanderbilt University Medical Center
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4
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Mason EC, Menon S, Schneider BR, Gaskill CF, Dawson MM, Moore CM, Armstrong LC, Cho O, Richmond BW, Kropski JA, West JD, Geraghty P, Gomperts BN, Ess KC, Gally F, Majka SM. Activation of mTOR signaling in adult lung microvascular progenitor cells accelerates lung aging. J Clin Invest 2023; 133:e171430. [PMID: 37874650 PMCID: PMC10721153 DOI: 10.1172/jci171430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023] Open
Abstract
Reactivation and dysregulation of the mTOR signaling pathway are a hallmark of aging and chronic lung disease; however, the impact on microvascular progenitor cells (MVPCs), capillary angiostasis, and tissue homeostasis is unknown. While the existence of an adult lung vascular progenitor has long been hypothesized, these studies show that Abcg2 enriches for a population of angiogenic tissue-resident MVPCs present in both adult mouse and human lungs using functional, lineage, and transcriptomic analyses. These studies link human and mouse MVPC-specific mTORC1 activation to decreased stemness, angiogenic potential, and disruption of p53 and Wnt pathways, with consequent loss of alveolar-capillary structure and function. Following mTOR activation, these MVPCs adapt a unique transcriptome signature and emerge as a venous subpopulation in the angiodiverse microvascular endothelial subclusters. Thus, our findings support a significant role for mTOR in the maintenance of MVPC function and microvascular niche homeostasis as well as a cell-based mechanism driving loss of tissue structure underlying lung aging and the development of emphysema.
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Affiliation(s)
- Emma C. Mason
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, National Jewish Health, Denver, Colorado, USA
| | - Swapna Menon
- Pulmonary Vascular Research Institute Kochi and AnalyzeDat Consulting Services, Kerala, India
| | - Benjamin R. Schneider
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, National Jewish Health, Denver, Colorado, USA
| | - Christa F. Gaskill
- Department of Dermatology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Maggie M. Dawson
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, National Jewish Health, Denver, Colorado, USA
| | - Camille M. Moore
- Department of Immunology and Genomic Medicine, Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Laura Craig Armstrong
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Okyong Cho
- Genomics and Microarray Core, University of Colorado Cancer Center, Anschutz Medical Center, Aurora, Colorado, USA
| | - Bradley W. Richmond
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center and Department of Veterans Affairs, Nashville, Tennessee, USA
| | - Jonathan A. Kropski
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center and Department of Veterans Affairs, Nashville, Tennessee, USA
| | - James D. West
- Department of Medicine, Division of Allergy, Pulmonary and Critical Care Medicine, Vanderbilt University Medical Center and Department of Veterans Affairs, Nashville, Tennessee, USA
| | - Patrick Geraghty
- Division of Pulmonary and Critical Care Medicine, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Brigitte N. Gomperts
- Translational Research, UCLA Broad Stem Cell Research Center; Pediatrics Division of Pulmonary Medicine, University of California, Los Angeles, California, USA
| | - Kevin C. Ess
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Fabienne Gally
- Department of Immunology and Genomic Medicine, Center for Genes, Environment and Health, National Jewish Health, Denver, Colorado, USA
- Department of Biostatistics and Informatics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Susan M. Majka
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, National Jewish Health, Denver, Colorado, USA
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado, USA
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5
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Hayes J, Mahoney AB, Ayers C, Sarma A, Ess KC, Hunley TE, Smith CM. A rare cause of posterior reversible encephalopathy syndrome: Acute lymphoblastic leukemia. Clin Case Rep 2023; 11:e8238. [PMID: 38028041 PMCID: PMC10659917 DOI: 10.1002/ccr3.8238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 06/08/2023] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Key Clinical Message The presentation of posterior reversible encephalopathy syndrome (PRES) as the initial presenting sign of acute lymphoblastic leukemia is unusual, as PRES is more often a complication of therapy. This case highlights the importance of maintaining a broad differential diagnosis for pediatric hypertension and its complications. Abstract A 6-year-old male presented with a seizure-like episode. Evaluation revealed hypertension and brain imaging showed findings consistent with posterior reversible encephalopathy syndrome. Complete blood count showed lymphoblasts, and the cause of his hypertension was determined to be renal infiltration of leukemia cells due to B-cell acute lymphoblastic leukemia.
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Affiliation(s)
- Jessica Hayes
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
| | - Anne Byrd Mahoney
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
- Division of Pediatric Hematology/OncologyVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Claci Ayers
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
- Division of Pediatric Emergency MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Asha Sarma
- Department of RadiologyVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
- Division of Pediatric NeurologyVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Tracy E. Hunley
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
- Division of Pediatric NephrologyVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Christine Moore Smith
- Department of Pediatrics, Vanderbilt University Medical CenterMonroe Carell Jr. Children's HospitalNashvilleTennesseeUSA
- Division of Pediatric Hematology/OncologyVanderbilt University Medical CenterNashvilleTennesseeUSA
- Vanderbilt‐Ingram Cancer CenterVanderbilt University Medical CenterNashvilleTennesseeUSA
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6
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Chalkley MBL, Mersfelder RB, Sundberg M, Armstrong LC, Sahin M, Ihrie RA, Ess KC. Non-canonical functions of a mutant TSC2 protein in mitotic division. PLoS One 2023; 18:e0292086. [PMID: 37792789 PMCID: PMC10550124 DOI: 10.1371/journal.pone.0292086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a debilitating developmental disorder characterized by a variety of clinical manifestations. TSC is caused by mutations in the TSC1 or TSC2 genes, which encode the hamartin/tuberin proteins respectively. These proteins function as a heterodimer that negatively regulates the mechanistic Target of Rapamycin Complex 1 (mTORC1). TSC research has focused on the effects of mTORC1, a critical signaling hub, on regulation of diverse cell processes including metabolism, cell growth, translation, and neurogenesis. However, non-canonical functions of TSC2 are not well studied, and the potential disease-relevant biological mechanisms of mutations affecting these functions are not well understood. We observed aberrant multipolar mitotic division, a novel phenotype, in TSC2 mutant iPSCs. The multipolar phenotype is not meaningfully affected by treatment with the inhibitor rapamycin. We further observed dominant negative activity of the mutant form of TSC2 in producing the multipolar division phenotype. These data expand the knowledge of TSC2 function and pathophysiology which will be highly relevant to future treatments for patients with TSC.
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Affiliation(s)
- Mary-Bronwen L. Chalkley
- Department of Cell & Developmental Biology, School of Medicine Basic Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Rachel B. Mersfelder
- Department of Cell & Developmental Biology, School of Medicine Basic Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Maria Sundberg
- Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Laura C. Armstrong
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Mustafa Sahin
- Rosamund Stone Zander Translational Neuroscience Center, Department of Neurology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rebecca A. Ihrie
- Department of Cell & Developmental Biology, School of Medicine Basic Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Kevin C. Ess
- Department of Cell & Developmental Biology, School of Medicine Basic Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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7
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Chun YW, Miyamoto M, Williams CH, Neitzel LR, Silver-Isenstadt M, Cadar AG, Fuller DT, Fong DC, Liu H, Lease R, Kim S, Katagiri M, Durbin MD, Wang KC, Feaster TK, Sheng CC, Neely MD, Sreenivasan U, Cortes-Gutierrez M, Finn AV, Schot R, Mancini GMS, Ament SA, Ess KC, Bowman AB, Han Z, Bichell DP, Su YR, Hong CC. Impaired Reorganization of Centrosome Structure Underlies Human Infantile Dilated Cardiomyopathy. Circulation 2023; 147:1291-1303. [PMID: 36970983 PMCID: PMC10133173 DOI: 10.1161/circulationaha.122.060985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 02/22/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND During cardiomyocyte maturation, the centrosome, which functions as a microtubule organizing center in cardiomyocytes, undergoes dramatic structural reorganization where its components reorganize from being localized at the centriole to the nuclear envelope. This developmentally programmed process, referred to as centrosome reduction, has been previously associated with cell cycle exit. However, understanding of how this process influences cardiomyocyte cell biology, and whether its disruption results in human cardiac disease, remains unknown. We studied this phenomenon in an infant with a rare case of infantile dilated cardiomyopathy (iDCM) who presented with left ventricular ejection fraction of 18% and disrupted sarcomere and mitochondria structure. METHODS We performed an analysis beginning with an infant who presented with a rare case of iDCM. We derived induced pluripotent stem cells from the patient to model iDCM in vitro. We performed whole exome sequencing on the patient and his parents for causal gene analysis. CRISPR/Cas9-mediated gene knockout and correction in vitro were used to confirm whole exome sequencing results. Zebrafish and Drosophila models were used for in vivo validation of the causal gene. Matrigel mattress technology and single-cell RNA sequencing were used to characterize iDCM cardiomyocytes further. RESULTS Whole exome sequencing and CRISPR/Cas9 gene knockout/correction identified RTTN, the gene encoding the centrosomal protein RTTN (rotatin), as the causal gene underlying the patient's condition, representing the first time a centrosome defect has been implicated in a nonsyndromic dilated cardiomyopathy. Genetic knockdowns in zebrafish and Drosophila confirmed an evolutionarily conserved requirement of RTTN for cardiac structure and function. Single-cell RNA sequencing of iDCM cardiomyocytes showed impaired maturation of iDCM cardiomyocytes, which underlie the observed cardiomyocyte structural and functional deficits. We also observed persistent localization of the centrosome at the centriole, contrasting with expected programmed perinuclear reorganization, which led to subsequent global microtubule network defects. In addition, we identified a small molecule that restored centrosome reorganization and improved the structure and contractility of iDCM cardiomyocytes. CONCLUSIONS This study is the first to demonstrate a case of human disease caused by a defect in centrosome reduction. We also uncovered a novel role for RTTN in perinatal cardiac development and identified a potential therapeutic strategy for centrosome-related iDCM. Future study aimed at identifying variants in centrosome components may uncover additional contributors to human cardiac disease.
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Affiliation(s)
- Young Wook Chun
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Matthew Miyamoto
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Charles H. Williams
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Leif R. Neitzel
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Maya Silver-Isenstadt
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Adrian G. Cadar
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Daniela T. Fuller
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Daniel C. Fong
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Hanhan Liu
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Robert Lease
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sungseek Kim
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Mikako Katagiri
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Matthew D. Durbin
- Division of Neonatology-Perinatology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 26202
| | - Kuo-Chen Wang
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Tromondae K. Feaster
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Calvin C. Sheng
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - M. Diana Neely
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37201
| | - Urmila Sreenivasan
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Marcia Cortes-Gutierrez
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aloke V. Finn
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Rachel Schot
- Division of Neonatology-Perinatology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 26202
| | - Grazia M. S. Mancini
- Department of Clinical Genetics, Erasmus University Medical Center (Erasmus MC), P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Seth A. Ament
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN37201
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47906
| | - Zhe Han
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - David P. Bichell
- Department of Pediatric Cardiac Surgery, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Yan Ru Su
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Charles C. Hong
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
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8
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Geben LC, Brockman AA, Chalkley MBL, Sweet SR, Gallagher JE, Scheuing AL, Simerly RB, Ess KC, Irish JM, Ihrie RA. Dephosphorylation of 4EBP1/2 Induces Prenatal Neural Stem Cell Quiescence. bioRxiv 2023:2023.02.14.528513. [PMID: 36824760 PMCID: PMC9948964 DOI: 10.1101/2023.02.14.528513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A limiting factor in the regenerative capacity of the adult brain is the abundance and proliferative ability of neural stem cells (NSCs). Adult NSCs are derived from a subpopulation of embryonic NSCs that temporarily enter quiescence during mid-gestation and remain quiescent until postnatal reactivation. Here we present evidence that the mechanistic/mammalian target of rapamycin (mTOR) pathway regulates quiescence entry in embryonic NSCs of the developing forebrain. Throughout embryogenesis, two downstream effectors of mTOR, p-4EBP1/2 T37/46 and p-S6 S240/244, were mutually exclusive in NSCs, rarely occurring in the same cell. While 4EBP1/2 was phosphorylated in stem cells undergoing mitosis at the ventricular surface, S6 was phosphorylated in more differentiated cells migrating away from the ventricle. Phosphorylation of 4EBP1/2, but not S6, was responsive to quiescence induction in cultured embryonic NSCs. Further, inhibition of p-4EBP1/2, but not p-S6, was sufficient to induce quiescence. Collectively, this work offers new insight into the regulation of quiescence entry in embryonic NSCs and, thereby, correct patterning of the adult brain. These data suggest unique biological functions of specific posttranslational modifications and indicate that the preferential inhibition of such modifications may be a useful therapeutic approach in neurodevelopmental diseases where NSC numbers, proliferation, and differentiation are altered.
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Affiliation(s)
- Laura C. Geben
- Program in Pharmacology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Asa A. Brockman
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | | | - Serena R. Sweet
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235, USA
| | - Julia E. Gallagher
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Alexandra L. Scheuing
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Richard B. Simerly
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
| | - Kevin C. Ess
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
| | - Jonathan M. Irish
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37235, USA
| | - Rebecca A. Ihrie
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, 37235, USA
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville TN 37235, USA
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9
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Miller DR, Schaffer DK, Neely MD, McClain ES, Travis AR, Block FE, Mckenzie J, Werner EM, Armstrong L, Markov DA, Bowman AB, Ess KC, Cliffel DE, Wikswo JP. A bistable, multiport valve enables microformulators creating microclinical analyzers that reveal aberrant glutamate metabolism in astrocytes derived from a tuberous sclerosis patient. Sens Actuators B Chem 2021; 341:129972. [PMID: 34092923 PMCID: PMC8174775 DOI: 10.1016/j.snb.2021.129972] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
There is a need for valves and pumps that operate at the microscale with precision and accuracy, are versatile in their application, and are easily fabricated. To that end, we developed a new rotary planar multiport valve to faithfully select solutions (contamination = 5.22 ± 0.06 ppb) and a rotary planar peristaltic pump to precisely control fluid delivery (flow rate = 2.4 ± 1.7 to 890 ± 77 μL/min). Both the valve and pump were implemented in a planar format amenable to single-layer soft lithographic fabrication. These planar microfluidics were actuated by a rotary motor controlled remotely by custom software. Together, these two devices constitute an innovative microformulator that was used to prepare precise, high-fidelity mixtures of up to five solutions (deviation from prescribed mixture = ±|0.02 ± 0.02| %). This system weighed less than a kilogram, occupied around 500 cm3, and generated pressures of 255 ± 47 kPa. This microformulator was then combined with an electrochemical sensor creating a microclinical analyzer (μCA) for detecting glutamate in real time. Using the chamber of the μCA as an in-line bioreactor, we compared glutamate homeostasis in human astrocytes differentiated from human-induced pluripotent stem cells (hiPSCs) from a control subject (CC-3) and a Tuberous Sclerosis Complex (TSC) patient carrying a pathogenic TSC2 mutation. When challenged with glutamate, TSC astrocytes took up less glutamate than control cells. These data validate the analytical power of the μCA and the utility of the microformulator by leveraging it to assess disease-related alterations in cellular homeostasis.
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Affiliation(s)
- Dusty R. Miller
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - David K. Schaffer
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, U.S.A
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - M. Diana Neely
- Department of Pediatrics, Vanderbilt University Medical Center, 1211 Medical Center Dr., Nashville, TN 37232, U.S.A
| | - Ethan S. McClain
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Adam R. Travis
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Frank E. Block
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Jennifer Mckenzie
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Erik M. Werner
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Laura Armstrong
- Department of Pediatrics, Vanderbilt University Medical Center, 1211 Medical Center Dr., Nashville, TN 37232, U.S.A
| | - Dmitry A. Markov
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, U.S.A
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - Aaron B. Bowman
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, U.S.A
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, U.S.A
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University Medical Center, 1211 Medical Center Dr., Nashville, TN 37232, U.S.A
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, U.S.A
| | - David E. Cliffel
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, U.S.A
| | - John P. Wikswo
- Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, U.S.A
- Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, U.S.A
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, U.S.A
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37240, U.S.A
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10
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Rosenblum HG, Hadler SC, Moulia D, Shimabukuro TT, Su JR, Tepper NK, Ess KC, Woo EJ, Mba-Jonas A, Alimchandani M, Nair N, Klein NP, Hanson KE, Markowitz LE, Wharton M, McNally VV, Romero JR, Talbot HK, Lee GM, Daley MF, Mbaeyi SA, Oliver SE. Use of COVID-19 Vaccines After Reports of Adverse Events Among Adult Recipients of Janssen (Johnson & Johnson) and mRNA COVID-19 Vaccines (Pfizer-BioNTech and Moderna): Update from the Advisory Committee on Immunization Practices - United States, July 2021. MMWR Morb Mortal Wkly Rep 2021; 70:1094-1099. [PMID: 34383735 PMCID: PMC8360272 DOI: 10.15585/mmwr.mm7032e4] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In December 2020, the Food and Drug Administration (FDA) issued Emergency Use Authorizations (EUAs) for Pfizer-BioNTech and Moderna COVID-19 vaccines, and in February 2021, FDA issued an EUA for the Janssen (Johnson & Johnson) COVID-19 vaccine. After each EUA, the Advisory Committee on Immunization Practices (ACIP) issued interim recommendations for vaccine use; currently Pfizer-BioNTech is authorized and recommended for persons aged ≥12 years and Moderna and Janssen for persons aged ≥18 years (1-3). Both Pfizer-BioNTech and Moderna vaccines, administered as 2-dose series, are mRNA-based COVID-19 vaccines, whereas the Janssen COVID-19 vaccine, administered as a single dose, is a recombinant replication-incompetent adenovirus-vector vaccine. As of July 22, 2021, 187 million persons in the United States had received at least 1 dose of COVID-19 vaccine (4); close monitoring of safety surveillance has demonstrated that serious adverse events after COVID-19 vaccination are rare (5,6). Three medical conditions have been reported in temporal association with receipt of COVID-19 vaccines. Two of these (thrombosis with thrombocytopenia syndrome [TTS], a rare syndrome characterized by venous or arterial thrombosis and thrombocytopenia, and Guillain-Barré syndrome [GBS], a rare autoimmune neurologic disorder characterized by ascending weakness and paralysis) have been reported after Janssen COVID-19 vaccination. One (myocarditis, cardiac inflammation) has been reported after Pfizer-BioNTech COVID-19 vaccination or Moderna COVID-19 vaccination, particularly after the second dose; these were reviewed together and will hereafter be referred to as mRNA COVID-19 vaccination. ACIP has met three times to review the data associated with these reports of serious adverse events and has comprehensively assessed the benefits and risks associated with receipt of these vaccines. During the most recent meeting in July 2021, ACIP determined that, overall, the benefits of COVID-19 vaccination in preventing COVID-19 morbidity and mortality outweigh the risks for these rare serious adverse events in adults aged ≥18 years; this balance of benefits and risks varied by age and sex. ACIP continues to recommend COVID-19 vaccination in all persons aged ≥12 years. CDC and FDA continue to closely monitor reports of serious adverse events and will present any additional data to ACIP for consideration. Information regarding risks and how they vary by age and sex and type of vaccine should be disseminated to providers, vaccine recipients, and the public.
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11
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Keller SR, Mallack EJ, Rubin JP, Accardo JA, Brault JA, Corre CS, Elizondo C, Garafola J, Jackson-Garcia AC, Rhee J, Seeger E, Shullanberger KC, Tourjee A, Trovato MK, Waldman AT, Wallace JL, Wallace MR, Werner K, White A, Ess KC, Becker C, Eichler FS. Practical Approaches and Knowledge Gaps in the Care for Children With Leukodystrophies. J Child Neurol 2021; 36:65-78. [PMID: 32875938 PMCID: PMC7736398 DOI: 10.1177/0883073820946154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Leukodystrophies are a group of neurodegenerative genetic disorders that affect approximately 1 in 7500 individuals. Despite therapeutic progress in individual leukodystrophies, guidelines in neurologic care are sparse and consensus among physicians and caregivers remains a challenge. At patient advocacy meetings hosted by Hunter's Hope from 2016-2018, multidisciplinary experts and caregivers met to conduct a literature review, identify knowledge gaps and summarize best practices regarding neurologic care. Stages of severity in leukodystrophies guided recommendations to address different levels of need based on a newly defined system of disease severity. Four core neurologic domains prioritized by families were identified and became the focus of this guideline: sleep, pain, seizures/epilepsy, and language/cognition. Based on clinical severity, the following categories were used: presymptomatic, early symptomatic, intermediate symptomatic, and advanced symptomatic. Across the leukodystrophies, neurologic care should be tailored to stages of severity while accounting for unique aspects of every disease and multiple knowledge gaps present. Standardized tools and surveys can help guide treatment but should not overburden families.
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Affiliation(s)
- Stephanie R. Keller
- Department of Pediatrics, Division of Pediatric Neurology, Emory University/Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Eric J. Mallack
- Department of Pediatrics, Division of Child Neurology, Weill Cornell
Medical College/New York-Presbyterian Hospital, New York, NY, USA
| | - Jennifer P. Rubin
- Department of Pediatric Neurology, Northwestern Feinberg School of
Medicine, Chicago, IL, USA
| | - Jennifer A. Accardo
- Department of Neurology, Children’s Hospital of Richmond at VCU,
Richmond, VA, USA
| | - Jennifer A. Brault
- Department of Pediatrics, Division of Pediatric Neurology Vanderbilt University Medical Center, Nashville, TN, USA
| | - Camille S. Corre
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Camila Elizondo
- East Boston Neighborhood Health Canter, East Boston, MA, USA
| | - Jennifer Garafola
- Department of Pediatrics, Division of Pediatric Neurology Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Jullie Rhee
- Children’s National Health Systems, Washington, DC, USA
| | | | | | - Amanda Tourjee
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Melissa K. Trovato
- Department of Physical Medicine and Rehabilitation, Kennedy Krieger Institute and Johns Hopkins University, Baltimore, MD, USA
| | - Amy T. Waldman
- Division of Neurology, The Children’s Hospital of Philadelphia,
University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Klaus Werner
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Angela White
- Department of Pediatrics, Division of Pediatric Neurology Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kevin C. Ess
- Department of Pediatrics, Division of Pediatric Neurology Vanderbilt University Medical Center, Nashville, TN, USA
| | - Catherine Becker
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Florian S. Eichler
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA,Florian S. Eichler, MD, Department of
Neurology, Massachusetts General Hospital, 175 Cambridge Street, Suite 340,
Boston, MA 02114, USA.
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12
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Klofas LK, Short BP, Snow JP, Sinnaeve J, Rushing GV, Westlake G, Weinstein W, Ihrie RA, Ess KC, Carson RP. DEPDC5 haploinsufficiency drives increased mTORC1 signaling and abnormal morphology in human iPSC-derived cortical neurons. Neurobiol Dis 2020; 143:104975. [PMID: 32574724 PMCID: PMC7462127 DOI: 10.1016/j.nbd.2020.104975] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/21/2020] [Accepted: 06/13/2020] [Indexed: 01/21/2023] Open
Abstract
Mutations in the DEPDC5 gene can cause epilepsy, including forms with and without brain malformations. The goal of this study was to investigate the contribution of DEPDC5 gene dosage to the underlying neuropathology of DEPDC5-related epilepsies. We generated induced pluripotent stem cells (iPSCs) from epilepsy patients harboring heterozygous loss of function mutations in DEPDC5. Patient iPSCs displayed increases in both phosphorylation of ribosomal protein S6 and proliferation rate, consistent with elevated mTORC1 activation. In line with these findings, we observed increased soma size in patient iPSC-derived cortical neurons that was rescued with rapamycin treatment. These data indicate that human cells heterozygous for DEPDC5 loss-of-function mutations are haploinsufficient for control of mTORC1 signaling. Our findings suggest that human pathology differs from mouse models of DEPDC5-related epilepsies, which do not show consistent phenotypic differences in heterozygous neurons, and support the need for human-based models to affirm and augment the findings from animal models of DEPDC5-related epilepsy.
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Affiliation(s)
- Lindsay K Klofas
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Brittany P Short
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John P Snow
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Justine Sinnaeve
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Grant Westlake
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Will Weinstein
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Rebecca A Ihrie
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kevin C Ess
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Robert P Carson
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.
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13
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Snow JP, Westlake G, Klofas LK, Jeon S, Armstrong LC, Swoboda KJ, George AL, Ess KC. Neuronal modeling of alternating hemiplegia of childhood reveals transcriptional compensation and replicates a trigger-induced phenotype. Neurobiol Dis 2020; 141:104881. [PMID: 32348881 DOI: 10.1016/j.nbd.2020.104881] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/18/2020] [Accepted: 04/24/2020] [Indexed: 01/30/2023] Open
Abstract
Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disease caused by heterozygous de novo missense mutations in the ATP1A3 gene that encodes the neuronal specific α3 subunit of the Na,K-ATPase (NKA) pump. Mechanisms underlying patient episodes including environmental triggers remain poorly understood, and there are no empirically proven treatments for AHC. In this study, we generated patient-specific induced pluripotent stem cells (iPSCs) and isogenic controls for the E815K ATP1A3 mutation that causes the most phenotypically severe form of AHC. Using an in vitro iPSC-derived cortical neuron disease model, we found elevated levels of ATP1A3 mRNA in AHC lines compared to controls, without significant perturbations in protein expression. Microelectrode array analyses demonstrated that in cortical neuronal cultures, ATP1A3+/E815K iPSC-derived neurons displayed less overall activity than neurons differentiated from isogenic mutation-corrected and unrelated control cell lines. However, induction of cellular stress by elevated temperature revealed a hyperactivity phenotype following heat stress in ATP1A3+/E815K neurons compared to control lines. Treatment with flunarizine, a drug commonly used to prevent AHC episodes, did not impact this stress-triggered phenotype. These findings support the use of iPSC-derived neuronal cultures for studying complex neurodevelopmental conditions such as AHC and provide a platform for mechanistic discovery in a human disease model.
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Affiliation(s)
- John P Snow
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Grant Westlake
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lindsay K Klofas
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Soyoun Jeon
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Laura C Armstrong
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kathryn J Swoboda
- Center for Genomic Medicine, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kevin C Ess
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
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14
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Xie Y, Ng NN, Safrina OS, Ramos CM, Ess KC, Schwartz PH, Smith MA, O'Dowd DK. Comparisons of dual isogenic human iPSC pairs identify functional alterations directly caused by an epilepsy associated SCN1A mutation. Neurobiol Dis 2019; 134:104627. [PMID: 31786370 DOI: 10.1016/j.nbd.2019.104627] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/05/2019] [Accepted: 09/26/2019] [Indexed: 02/06/2023] Open
Abstract
Over 1250 mutations in SCN1A, the Nav1.1 voltage-gated sodium channel gene, are associated with seizure disorders including GEFS+. To evaluate how a specific mutation, independent of genetic background, causes seizure activity we generated two pairs of isogenic human iPSC lines by CRISPR/Cas9 gene editing. One pair is a control line from an unaffected sibling, and the mutated control carrying the GEFS+ K1270T SCN1A mutation. The second pair is a GEFS+ patient line with the K1270T mutation, and the corrected patient line. By comparing the electrophysiological properties in inhibitory and excitatory iPSC-derived neurons from these pairs, we found the K1270T mutation causes cell type-specific alterations in sodium current density and evoked firing, resulting in hyperactive neural networks. We also identified differences associated with genetic background and interaction between the mutation and genetic background. Comparisons within and between dual pairs of isogenic iPSC-derived neuronal cultures provide a novel platform for evaluating cellular mechanisms underlying a disease phenotype and for developing patient-specific anti-seizure therapies.
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Affiliation(s)
- Yunyao Xie
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States of America
| | - Nathan N Ng
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States of America
| | - Olga S Safrina
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States of America
| | - Carmen M Ramos
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States of America
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Philip H Schwartz
- Children's Hospital of Orange County Research Institute, Orange, CA, United States of America
| | - Martin A Smith
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, United States of America
| | - Diane K O'Dowd
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States of America.
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15
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Gewin LS, Summers ME, Harral JW, Gaskill CF, Khodo SN, Neelisetty S, Sullivan TM, Hopp K, Reese JJ, Klemm DJ, Kon V, Ess KC, Shi W, Majka SM. Inactivation of Tsc2 in Abcg2 lineage-derived cells drives the appearance of polycystic lesions and fibrosis in the adult kidney. Am J Physiol Renal Physiol 2019; 317:F1201-F1210. [PMID: 31461347 PMCID: PMC6879939 DOI: 10.1152/ajprenal.00629.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 08/07/2019] [Accepted: 08/22/2019] [Indexed: 02/08/2023] Open
Abstract
Tuberous sclerosis complex 2 (TSC2), or tuberin, is a pivotal regulator of the mechanistic target of rapamycin signaling pathway that controls cell survival, proliferation, growth, and migration. Loss of Tsc2 function manifests in organ-specific consequences, the mechanisms of which remain incompletely understood. Recent single cell analysis of the kidney has identified ATP-binding cassette G2 (Abcg2) expression in renal proximal tubules of adult mice as well as a in a novel cell population. The impact in adult kidney of Tsc2 knockdown in the Abcg2-expressing lineage has not been evaluated. We engineered an inducible system in which expression of truncated Tsc2, lacking exons 36-37 with an intact 3' region and polycystin 1, is driven by Abcg2. Here, we demonstrate that selective expression of Tsc2fl36-37 in the Abcg2pos lineage drives recombination in proximal tubule epithelial and rare perivascular mesenchymal cells, which results in progressive proximal tubule injury, impaired kidney function, formation of cystic lesions, and fibrosis in adult mice. These data illustrate the critical importance of Tsc2 function in the Abcg2-expressing proximal tubule epithelium and mesenchyme during the development of cystic lesions and remodeling of kidney parenchyma.
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Affiliation(s)
- Leslie S Gewin
- Division of Nephrology and Hypertension or Allergy, Department of Medicine, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
- Department of Medicine, Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, Tennessee
| | - Megan E Summers
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Julie W Harral
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
| | - Christa F Gaskill
- Division of Nephrology and Hypertension or Allergy, Department of Medicine, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville, Tennessee
| | - Stellor Nlandu Khodo
- Division of Nephrology and Hypertension or Allergy, Department of Medicine, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville, Tennessee
| | - Surekha Neelisetty
- Division of Nephrology and Hypertension or Allergy, Department of Medicine, Pulmonary, and Critical Care Medicine, Vanderbilt University, Nashville, Tennessee
| | - Timothy M Sullivan
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Katharina Hopp
- Division of Renal Diseases and Hypertension, Department of Medicine, University of Colorado, Aurora, Colorado
| | - J Jeffrey Reese
- Division of Nephrology or Neonatology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dwight J Klemm
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Colorado, Aurora, Colorado
| | - Valentina Kon
- Division of Nephrology or Neonatology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kevin C Ess
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Wei Shi
- Children's Hospital of Los Angeles, Developmental Biology and Regenerative Medicine Program at the Saban Research Institute, Los Angeles, California
| | - Susan M Majka
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, National Jewish Health, Denver, Colorado
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado
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16
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Affiliation(s)
- Kevin C Ess
- From the Departments of Pediatrics and Neurology (K.C.E.), Vanderbilt University Medical Center, Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN; and Departments of Pediatrics and Neurology (D.N.F.), University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, OH
| | - David Neal Franz
- From the Departments of Pediatrics and Neurology (K.C.E.), Vanderbilt University Medical Center, Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, TN; and Departments of Pediatrics and Neurology (D.N.F.), University of Cincinnati College of Medicine, Cincinnati Children's Hospital Medical Center, OH
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17
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Short B, Kozek L, Harmsen H, Zhang B, Wong M, Ess KC, Fu C, Naftel R, Pearson MM, Carson RP. Cerebral aquaporin-4 expression is independent of seizures in tuberous sclerosis complex. Neurobiol Dis 2019; 129:93-101. [PMID: 31078684 DOI: 10.1016/j.nbd.2019.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/23/2019] [Accepted: 05/08/2019] [Indexed: 12/26/2022] Open
Abstract
Astrocytes serve many functions in the human brain, many of which focus on maintenance of homeostasis. Astrocyte dysfunction in Tuberous Sclerosis Complex (TSC) has long been appreciated with activation of the mTORC1 signaling pathway resulting in gliosis and possibly contributing to the very frequent phenotype of epilepsy. We hypothesized that aberrant expression of the astrocyte protein aquaporin-4 (AQP4) may be present in TSC and contribute to disease pathology. Characterization of AQP4 expression in epileptic cortex from TSC patients demonstrated a diffuse increase in AQP4. To determine if this was due to exposure to seizures, we examined Aqp4 expression in mouse models of TSC in which Tsc1 or Tsc2 inactivation was targeted to astrocytes or glial progenitors, respectively. Loss of either Tsc1 or Tsc2 from astrocytes resulted in a marked increase in Aqp4 expression which was sensitive to mTORC1 inhibition with rapamycin. Our findings in both TSC epileptogenic cortex and in a variety of astrocyte culture models demonstrate for the first time that AQP4 expression is dysregulated in TSC. The extent to which AQP4 contributes to epilepsy in TSC is not known, though the similarities in AQP4 expression between TSC and temporal lobe epilepsy supports further studies targeting AQP4 in TSC.
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Affiliation(s)
- Brittany Short
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, United States
| | - Lindsay Kozek
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, United States; Vanderbilt Brain Institute, Vanderbilt University, United States
| | - Hannah Harmsen
- Department of Pathology, Vanderbilt University Medical Center, United States
| | - Bo Zhang
- Departments of Neurology, Pediatrics, and Neuroscience, Washington University School of Medicine, United States
| | - Michael Wong
- Departments of Neurology, Pediatrics, and Neuroscience, Washington University School of Medicine, United States
| | - Kevin C Ess
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, United States; Vanderbilt Brain Institute, Vanderbilt University, United States
| | - Cary Fu
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, United States
| | - Robert Naftel
- Department of Neurosurgery, Vanderbilt University Medical Center, United States
| | | | - Robert P Carson
- Department of Pediatrics, Division of Pediatric Neurology, Vanderbilt University Medical Center, United States; Vanderbilt Brain Institute, Vanderbilt University, United States; Department of Pharmacology, Vanderbilt University Medical Center, United States.
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18
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Rushing GV, Brockman AA, Bollig MK, Leelatian N, Mobley BC, Irish JM, Ess KC, Fu C, Ihrie RA. Location-dependent maintenance of intrinsic susceptibility to mTORC1-driven tumorigenesis. Life Sci Alliance 2019; 2:2/2/e201800218. [PMID: 30910807 PMCID: PMC6435042 DOI: 10.26508/lsa.201800218] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 01/18/2023] Open
Abstract
Per-cell quantification of mTORC1 signaling activity in neural stem/progenitor cells reveals differential signaling, proliferative, and tumor-forming capability between dorsal and ventral cells within a single niche. Neural stem/progenitor cells (NSPCs) of the ventricular–subventricular zone (V-SVZ) are candidate cells of origin for many brain tumors. However, whether NSPCs in different locations within the V-SVZ differ in susceptibility to tumorigenic mutations is unknown. Here, single-cell measurements of signal transduction intermediates in the mechanistic target of rapamycin complex 1 (mTORC1) pathway reveal that ventral NSPCs have higher levels of signaling than dorsal NSPCs. These features are linked with differences in mTORC1-driven disease severity: introduction of a pathognomonic Tsc2 mutation only results in formation of tumor-like masses from the ventral V-SVZ. We propose a direct link between location-dependent intrinsic growth properties imbued by mTORC1 and predisposition to tumor development.
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Affiliation(s)
- Gabrielle V Rushing
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Asa A Brockman
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Madelyn K Bollig
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nalin Leelatian
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Bret C Mobley
- Department of Pathology, Immunology, and Microbiology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jonathan M Irish
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Pathology, Immunology, and Microbiology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kevin C Ess
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Rebecca A Ihrie
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA .,Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
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19
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Simmons CQ, Thompson CH, Cawthon BE, Westlake G, Swoboda KJ, Kiskinis E, Ess KC, George AL. Direct evidence of impaired neuronal Na/K-ATPase pump function in alternating hemiplegia of childhood. Neurobiol Dis 2018; 115:29-38. [PMID: 29567111 DOI: 10.1016/j.nbd.2018.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 02/23/2018] [Accepted: 03/17/2018] [Indexed: 12/16/2022] Open
Abstract
Mutations in ATP1A3 encoding the catalytic subunit of the Na/K-ATPase expressed in mammalian neurons cause alternating hemiplegia of childhood (AHC) as well as an expanding spectrum of other neurodevelopmental syndromes and neurological phenotypes. Most AHC cases are explained by de novo heterozygous ATP1A3 mutations, but the fundamental molecular and cellular consequences of these mutations in human neurons are not known. In this study, we investigated the electrophysiological properties of neurons generated from AHC patient-specific induced pluripotent stem cells (iPSCs) to ascertain functional disturbances underlying this neurological disease. Fibroblasts derived from two subjects with AHC, a male and a female, both heterozygous for the common ATP1A3 mutation G947R, were reprogrammed to iPSCs. Neuronal differentiation of iPSCs was initiated by neurogenin-2 (NGN2) induction followed by co-culture with mouse glial cells to promote maturation of cortical excitatory neurons. Whole-cell current clamp recording demonstrated that, compared with control iPSC-derived neurons, neurons differentiated from AHC iPSCs exhibited a significantly lower level of ouabain-sensitive outward current ('pump current'). This finding correlated with significantly depolarized potassium equilibrium potential and depolarized resting membrane potential in AHC neurons compared with control neurons. In this cellular model, we also observed a lower evoked action potential firing frequency when neurons were held at their resting potential. However, evoked action potential firing frequencies were not different between AHC and control neurons when the membrane potential was clamped to -80 mV. Impaired neuronal excitability could be explained by lower voltage-gated sodium channel availability at the depolarized membrane potential observed in AHC neurons. Our findings provide direct evidence of impaired neuronal Na/K-ATPase ion transport activity in human AHC neurons and demonstrate the potential impact of this genetic defect on cellular excitability.
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Affiliation(s)
- Christine Q Simmons
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Bryan E Cawthon
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Grant Westlake
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kathryn J Swoboda
- Center for Genomic Medicine, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Evangelos Kiskinis
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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20
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Xie Y, Schutte RJ, Ng NN, Ess KC, Schwartz PH, O'Dowd DK. Reproducible and efficient generation of functionally active neurons from human hiPSCs for preclinical disease modeling. Stem Cell Res 2017; 26:84-94. [PMID: 29272856 PMCID: PMC5899925 DOI: 10.1016/j.scr.2017.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/22/2017] [Accepted: 12/07/2017] [Indexed: 02/08/2023] Open
Abstract
The use of human induced pluripotent stem cell (hiPSC)-derived neuronal cultures to study the mechanisms of neurological disorders is often limited by low efficiency and high variability in differentiation of functional neurons. Here we compare the functional properties of neurons in cultures prepared with two hiPSC differentiation protocols, both plated on astroglial feeder layers. Using a protocol with an expandable intermediate stage, only a small percentage of cells with neuronal morphology were excitable by 21-23days in culture. In contrast, a direct differentiation strategy of the same hiPSC line produced cultures in which the majority of neurons fired action potentials as early as 4-5days. By 35-38days over 80% of the neurons fired repetitively and many fired spontaneously. Spontaneous post-synaptic currents were observed in ~40% of the neurons at 4-5days and in ~80% by 21-23days. The majority (75%) received both glutamatergic and GABAergic spontaneous postsynaptic currents. The rate and degree of maturation of excitability and synaptic activity was similar between multiple independent platings from a single hiPSC line, and between two different control hiPSC lines. Cultures of rapidly functional neurons will facilitate identification of cellular mechanisms underlying genetically defined neurological disorders and development of novel therapeutics.
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Affiliation(s)
- Yunyao Xie
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, United States
| | - Ryan J Schutte
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, United States
| | - Nathan N Ng
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, United States
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Philip H Schwartz
- Children's Hospital of Orange County Research Institute, Orange, CA, United States
| | - Diane K O'Dowd
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA, United States.
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21
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Armstrong LC, Westlake G, Snow JP, Cawthon B, Armour E, Bowman AB, Ess KC. Heterozygous loss of TSC2 alters p53 signaling and human stem cell reprogramming. Hum Mol Genet 2017; 26:4629-4641. [PMID: 28973543 PMCID: PMC5886307 DOI: 10.1093/hmg/ddx345] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/28/2017] [Accepted: 09/01/2017] [Indexed: 12/21/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a pediatric disorder of dysregulated growth and differentiation caused by loss of function mutations in either the TSC1 or TSC2 genes, which regulate mTOR kinase activity. To study aberrations of early development in TSC, we generated induced pluripotent stem cells using dermal fibroblasts obtained from patients with TSC. During validation, we found that stem cells generated from TSC patients had a very high rate of integration of the reprogramming plasmid containing a shRNA against TP53. We also found that loss of one allele of TSC2 in human fibroblasts is sufficient to increase p53 levels and impair stem cell reprogramming. Increased p53 was also observed in TSC2 heterozygous and homozygous mutant human stem cells, suggesting that the interactions between TSC2 and p53 are consistent across cell types and gene dosage. These results support important contributions of TSC2 heterozygous and homozygous mutant cells to the pathogenesis of TSC and the important role of p53 during reprogramming.
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Affiliation(s)
- Laura C Armstrong
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - Grant Westlake
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - John P Snow
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - Bryan Cawthon
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - Eric Armour
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - Aaron B Bowman
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
| | - Kevin C Ess
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, D4105 Medical Center North, Nashville, TN 37232, USA
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22
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Grier MD, West KL, Kelm ND, Fu C, Does MD, Parker B, McBrier E, Lagrange AH, Ess KC, Carson RP. Loss of mTORC2 signaling in oligodendrocyte precursor cells delays myelination. PLoS One 2017; 12:e0188417. [PMID: 29161318 PMCID: PMC5697806 DOI: 10.1371/journal.pone.0188417] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/07/2017] [Indexed: 11/26/2022] Open
Abstract
Myelin abnormalities are increasingly being recognized as an important component of a number of neurologic developmental disorders. The integration of many signaling pathways and cell types are critical for correct myelinogenesis. The PI3-K and mechanistic target of rapamycin (mTOR) pathways have been found to play key roles. mTOR is found within two distinct complexes, mTORC1 and mTORC2. mTORC1 activity has been shown to play a major role during myelination, while the role of mTORC2 is not yet well understood. To determine the role of mTORC2 signaling in myelinogenesis, we generated a mouse lacking the critical mTORC2 component Rictor in oligodendrocyte precursors (OPCs). Targeted deletion of Rictor in these cells decreases and delays the expression of myelin related proteins and reduces the size of cerebral white matter tracts. This is developmentally manifest as a transient reduction in myelinated axon density and g-ratio. OPC cell number is reduced at birth without detectable change in proliferation with proportional reductions in mature oligodendrocyte number at P15. The total number of oligodendrocytes as well as extent of myelination, does improve over time. Adult conditional knock-out (CKO) animals do not demonstrate a behavioral phenotype likely due in part to preserved axonal conduction velocities. These data support and extend prior studies demonstrating an important but transient contribution of mTORC2 signaling to myelin development.
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Affiliation(s)
- Mark D. Grier
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Kathryn L. West
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Nathaniel D. Kelm
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Mark D. Does
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Brittany Parker
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Eleanor McBrier
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Andre H. Lagrange
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Robert P. Carson
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- * E-mail:
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23
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Sahin M, Henske EP, Manning BD, Ess KC, Bissler JJ, Klann E, Kwiatkowski DJ, Roberds SL, Silva AJ, Hillaire-Clarke CS, Young LR, Zervas M, Mamounas LA. Advances and Future Directions for Tuberous Sclerosis Complex Research: Recommendations From the 2015 Strategic Planning Conference. Pediatr Neurol 2016; 60:1-12. [PMID: 27267556 PMCID: PMC4921275 DOI: 10.1016/j.pediatrneurol.2016.03.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 03/24/2016] [Indexed: 11/17/2022]
Abstract
On March 10 to March 12, 2015, the National Institute of Neurological Disorders and Stroke and the Tuberous Sclerosis Alliance sponsored a workshop in Bethesda, Maryland, to assess progress and new opportunities for research in tuberous sclerosis complex with the goal of updating the 2003 Research Plan for Tuberous Sclerosis (http://www.ninds.nih.gov/about_ninds/plans/tscler_research_plan.htm). In addition to the National Institute of Neurological Disorders and Stroke and Tuberous Sclerosis Alliance, participants in the strategic planning effort and workshop included representatives from six other Institutes of the National Institutes of Health, the Department of Defense Tuberous Sclerosis Complex Research Program, and a broad cross-section of basic scientists and clinicians with expertise in tuberous sclerosis complex along with representatives from the pharmaceutical industry. Here we summarize the outcomes from the extensive premeeting deliberations and final workshop recommendations, including (1) progress in the field since publication of the initial 2003 research plan for tuberous sclerosis complex, (2) the key gaps, needs, and challenges that hinder progress in tuberous sclerosis complex research, and (3) a new set of research priorities along with specific recommendations for addressing the major challenges in each priority area. The new research plan is organized around both short-term and long-term goals with the expectation that progress toward specific objectives can be achieved within a five to ten year time frame.
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Affiliation(s)
- Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
| | - Elizabeth P Henske
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Brendan D Manning
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | - Kevin C Ess
- Vanderbilt Kennedy Center for Research on Human Development, Department of Pediatrics, Vanderbilt University, Nashville, Tennessee
| | - John J Bissler
- University of Tennessee Health Science Center, Le Bonheur Children's Hospital and St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Eric Klann
- Center for Neural Science, New York University, New York, New York
| | - David J Kwiatkowski
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Alcino J Silva
- Departments of Neurobiology, Psychiatry and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California at Los Angeles, Los Angeles, California
| | - Coryse St Hillaire-Clarke
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Lisa R Young
- Division of Pulmonary Medicine, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee; Division of Allergy, Pulmonary, and Critical Care, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Mark Zervas
- Department of Neuroscience, Amgen Inc, Cambridge, Massachusetts
| | - Laura A Mamounas
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.
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24
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Tidball AM, Neely MD, Chamberlin R, Aboud AA, Kumar KK, Han B, Bryan MR, Aschner M, Ess KC, Bowman AB. Genomic Instability Associated with p53 Knockdown in the Generation of Huntington's Disease Human Induced Pluripotent Stem Cells. PLoS One 2016; 11:e0150372. [PMID: 26982737 PMCID: PMC4794230 DOI: 10.1371/journal.pone.0150372] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 02/13/2016] [Indexed: 12/20/2022] Open
Abstract
Alterations in DNA damage response and repair have been observed in Huntington's disease (HD). We generated induced pluripotent stem cells (iPSC) from primary dermal fibroblasts of 5 patients with HD and 5 control subjects. A significant fraction of the HD iPSC lines had genomic abnormalities as assessed by karyotype analysis, while none of our control lines had detectable genomic abnormalities. We demonstrate a statistically significant increase in genomic instability in HD cells during reprogramming. We also report a significant association with repeat length and severity of this instability. Our karyotypically normal HD iPSCs also have elevated ATM-p53 signaling as shown by elevated levels of phosphorylated p53 and H2AX, indicating either elevated DNA damage or hypersensitive DNA damage signaling in HD iPSCs. Thus, increased DNA damage responses in the HD genotype is coincidental with the observed chromosomal aberrations. We conclude that the disease causing mutation in HD increases the propensity of chromosomal instability relative to control fibroblasts specifically during reprogramming to a pluripotent state by a commonly used episomal-based method that includes p53 knockdown.
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Affiliation(s)
- Andrew M. Tidball
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - M. Diana Neely
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Reed Chamberlin
- Genetics Associates Inc., Nashville, TN, 37203, United States of America
| | - Asad A. Aboud
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
| | - Kevin K. Kumar
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Bingying Han
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
| | - Miles R. Bryan
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, United States of America
| | - Kevin C. Ess
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
| | - Aaron B. Bowman
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, 37240, United States of America
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center in Molecular Toxicology, Vanderbilt University, Nashville, TN, 37232, United States of America
- * E-mail:
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25
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Carson RP, Kelm ND, West KL, Does MD, Fu C, Weaver G, McBrier E, Parker B, Grier MD, Ess KC. Hypomyelination following deletion of Tsc2 in oligodendrocyte precursors. Ann Clin Transl Neurol 2015; 2:1041-54. [PMID: 26734657 PMCID: PMC4693589 DOI: 10.1002/acn3.254] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/14/2015] [Accepted: 08/27/2015] [Indexed: 12/17/2022] Open
Abstract
Objective While abnormalities in myelin in tuberous sclerosis complex (TSC) have been known for some time, recent imaging‐based data suggest myelin abnormalities may be independent of the pathognomonic cortical lesions (“tubers”). Multiple mouse models of TSC exhibit myelination deficits, though the cell types responsible and the mechanisms underlying the myelin abnormalities remain unclear. Methods To determine the role of alterations in mTOR signaling in myelination, we generated a conditional knockout (CKO) mouse model using Cre‐recombinase and the Olig2 promoter to inactivate the Tsc2 gene in oligodendrocyte precursor cells. Results Characterization of myelin and myelin constituent proteins demonstrated a marked hypomyelination phenotype. Diffusion‐based magnetic resonance imaging studies were likewise consistent with hypomyelination. Hypomyelination was due in part to decreased myelinated axon density and myelin thickness as well as decreased oligodendrocyte numbers. Coincident with hypomyelination, an extensive gliosis was seen in both the cortex and white matter tracks, suggesting alterations in cell fate due to changes in mTOR activity in oligodendrocyte precursors. Despite a high‐frequency appendicular tremor and altered gait in CKO mice, no significant changes in activity, vocalizations, or anxiety‐like phenotypes were seen. Interpretation Our findings support a known role of mTOR signaling in regulation of myelination and demonstrate that increased mTORC1 activity early in development within oligodendrocytes results in hypomyelination and not hypermyelination. Our data further support a dissociation between decreased Akt activity and increased mTORC1 activity toward hypomyelination. Thus, therapies promoting activation of Akt‐dependent pathways while reducing mTORC1 activity may prove beneficial in treatment of human disease.
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Affiliation(s)
- Robert P Carson
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Nathaniel D Kelm
- Department of Biomedical Engineering Vanderbilt University Nashville Tennessee
| | - Kathryn L West
- Department of Biomedical Engineering Vanderbilt University Nashville Tennessee
| | - Mark D Does
- Department of Biomedical Engineering Vanderbilt University Nashville Tennessee
| | - Cary Fu
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Grace Weaver
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Eleanor McBrier
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Brittany Parker
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Mark D Grier
- Department of Pediatrics Vanderbilt University Nashville Tennessee
| | - Kevin C Ess
- Department of Pediatrics Vanderbilt University Nashville Tennessee
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26
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Ess KC, Chugani HT. Dynamic tubers in tuberous sclerosis complex: A window for intervention? Neurology 2015; 85:1530-1. [PMID: 26432847 DOI: 10.1212/wnl.0000000000002056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Kevin C Ess
- From the Division of Pediatric Neurology (K.C.E.), Vanderbilt University Medical Center, Nashville, TN; and Division of Pediatric Neurology (H.T.C.), PET Center Children's Hospital of Michigan, Detroit.
| | - Harry T Chugani
- From the Division of Pediatric Neurology (K.C.E.), Vanderbilt University Medical Center, Nashville, TN; and Division of Pediatric Neurology (H.T.C.), PET Center Children's Hospital of Michigan, Detroit
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27
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Kelm ND, West KL, Carson RP, Gochberg DF, Ess KC, Does MD. Evaluation of diffusion kurtosis imaging in ex vivo hypomyelinated mouse brains. Neuroimage 2015; 124:612-626. [PMID: 26400013 DOI: 10.1016/j.neuroimage.2015.09.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 09/05/2015] [Accepted: 09/11/2015] [Indexed: 11/26/2022] Open
Abstract
Diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), and DKI-derived white matter tract integrity metrics (WMTI) were experimentally evaluated ex vivo through comparisons to histological measurements and established magnetic resonance imaging (MRI) measures of myelin in two knockout mouse models with varying degrees of hypomyelination. DKI metrics of mean and radial kurtosis were found to be better indicators of myelin content than conventional DTI metrics. The biophysical WMTI model based on the DKI framework reported on axon water fraction with good accuracy in cases with near normal axon density, but did not provide additional specificity to myelination. Overall, DKI provided additional information regarding white matter microstructure compared with DTI, making it an attractive method for future assessments of white matter development and pathology.
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Affiliation(s)
- Nathaniel D Kelm
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA
| | - Kathryn L West
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA
| | - Robert P Carson
- Department of Pediatrics, Vanderbilt University School of Medicine, USA; Department of Neurology, Vanderbilt University School of Medicine, USA
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA; Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University School of Medicine, USA; Department of Neurology, Vanderbilt University School of Medicine, USA
| | - Mark D Does
- Department of Biomedical Engineering, Vanderbilt University, USA; Vanderbilt University Institute of Imaging Science, Vanderbilt University, USA; Department of Radiology and Radiological Sciences, Vanderbilt University School of Medicine, USA; Department of Electrical Engineering, Vanderbilt University, USA.
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28
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Chun YW, Balikov DA, Feaster TK, Williams CH, Sheng CC, Lee JB, Boire TC, Neely MD, Bellan LM, Ess KC, Bowman AB, Sung HJ, Hong CC. Combinatorial polymer matrices enhance in vitro maturation of human induced pluripotent stem cell-derived cardiomyocytes. Biomaterials 2015. [PMID: 26204225 DOI: 10.1016/j.biomaterials.2015.07.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cardiomyocytes derived from human induced pluripotent stem cells (iPSC-CMs) hold great promise for modeling human heart diseases. However, iPSC-CMs studied to date resemble immature embryonic myocytes and therefore do not adequately recapitulate native adult cardiomyocyte phenotypes. Since extracellular matrix plays an essential role in heart development and maturation in vivo, we sought to develop a synthetic culture matrix that could enhance functional maturation of iPSC-CMs in vitro. In this study, we employed a library of combinatorial polymers comprising of three functional subunits - poly-ε-caprolacton (PCL), polyethylene glycol (PEG), and carboxylated PCL (cPCL) - as synthetic substrates for culturing human iPSC-CMs. Of these, iPSC-CMs cultured on 4%PEG-96%PCL (each % indicates the corresponding molar ratio) exhibit the greatest contractility and mitochondrial function. These functional enhancements are associated with increased expression of cardiac myosin light chain-2v, cardiac troponin I and integrin alpha-7. Importantly, iPSC-CMs cultured on 4%PEG-96%PCL demonstrate troponin I (TnI) isoform switch from the fetal slow skeletal TnI (ssTnI) to the postnatal cardiac TnI (cTnI), the first report of such transition in vitro. Finally, culturing iPSC-CMs on 4%PEG-96%PCL also significantly increased expression of genes encoding intermediate filaments known to transduce integrin-mediated mechanical signals to the myofilaments. In summary, our study demonstrates that synthetic culture matrices engineered from combinatorial polymers can be utilized to promote in vitro maturation of human iPSC-CMs through the engagement of critical matrix-integrin interactions.
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Affiliation(s)
- Young Wook Chun
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Daniel A Balikov
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Tromondae K Feaster
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Charles H Williams
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Calvin C Sheng
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jung-Bok Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Timothy C Boire
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - M Diana Neely
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Leon M Bellan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA; Department of Mechanical Engineering, Vanderbilt University, Nashville, TN 37235, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Aaron B Bowman
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hak-Joon Sung
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA.
| | - Charles C Hong
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Research Medicine, Veterans Affairs TVHS, Nashville, TN 37212, USA.
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Kim SH, Wu SY, Baek JI, Choi SY, Su Y, Flynn CR, Gamse JT, Ess KC, Hardiman G, Lipschutz JH, Abumrad NN, Rockey DC. A post-developmental genetic screen for zebrafish models of inherited liver disease. PLoS One 2015; 10:e0125980. [PMID: 25950913 PMCID: PMC4423964 DOI: 10.1371/journal.pone.0125980] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/27/2015] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease such as simple steatosis, nonalcoholic steatohepatitis (NASH), cirrhosis and fibrosis. However, the molecular pathogenesis and genetic variations causing NAFLD are poorly understood. The high prevalence and incidence of NAFLD suggests that genetic variations on a large number of genes might be involved in NAFLD. To identify genetic variants causing inherited liver disease, we used zebrafish as a model system for a large-scale mutant screen, and adopted a whole genome sequencing approach for rapid identification of mutated genes found in our screen. Here, we report on a forward genetic screen of ENU mutagenized zebrafish. From 250 F2 lines of ENU mutagenized zebrafish during post-developmental stages (5 to 8 days post fertilization), we identified 19 unique mutant zebrafish lines displaying visual evidence of hepatomegaly and/or steatosis with no developmental defects. Histological analysis of mutants revealed several specific phenotypes, including common steatosis, micro/macrovesicular steatosis, hepatomegaly, ballooning, and acute hepatocellular necrosis. This work has identified multiple post-developmental mutants and establishes zebrafish as a novel animal model for post-developmental inherited liver disease.
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Affiliation(s)
- Seok-Hyung Kim
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
- * E-mail:
| | - Shu-Yu Wu
- Department of Biology, Vanderbilt University, Nashville, TN, 37232, the United States of America
| | - Jeong-In Baek
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
| | - Soo Young Choi
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
| | - Yanhui Su
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
| | - Charles R. Flynn
- Department of Surgery, Vanderbilt University, Nashville, TN, 37232, the United States of America
| | - Joshua T. Gamse
- Department of Biology, Vanderbilt University, Nashville, TN, 37232, the United States of America
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University, Nashville, TN, 37232, the United States of America
| | - Gary Hardiman
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
| | - Joshua H. Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
- Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, 29401, the United States of America
| | - Naji N. Abumrad
- Department of Surgery, Vanderbilt University, Nashville, TN, 37232, the United States of America
| | - Don C. Rockey
- Department of Medicine, Medical University of South Carolina, Charleston, SC, 29425, the United States of America
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Thomas LR, Wang Q, Grieb BC, Phan J, Foshage AM, Sun Q, Olejniczak ET, Clark T, Dey S, Lorey S, Alicie B, Howard GC, Cawthon B, Ess KC, Eischen CM, Zhao Z, Fesik SW, Tansey WP. Interaction with WDR5 promotes target gene recognition and tumorigenesis by MYC. Mol Cell 2015; 58:440-52. [PMID: 25818646 DOI: 10.1016/j.molcel.2015.02.028] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/09/2015] [Accepted: 02/20/2015] [Indexed: 12/28/2022]
Abstract
MYC is an oncoprotein transcription factor that is overexpressed in the majority of malignancies. The oncogenic potential of MYC stems from its ability to bind regulatory sequences in thousands of target genes, which depends on interaction of MYC with its obligate partner, MAX. Here, we show that broad association of MYC with chromatin also depends on interaction with the WD40-repeat protein WDR5. MYC binds WDR5 via an evolutionarily conserved "MYC box IIIb" motif that engages a shallow, hydrophobic cleft on the surface of WDR5. Structure-guided mutations in MYC that disrupt interaction with WDR5 attenuate binding of MYC at ∼80% of its chromosomal locations and disable its ability to promote induced pluripotent stem cell formation and drive tumorigenesis. Our data reveal WDR5 as a key determinant for MYC recruitment to chromatin and uncover a tractable target for the discovery of anticancer therapies against MYC-driven tumors.
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Affiliation(s)
- Lance R Thomas
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Qingguo Wang
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Brian C Grieb
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jason Phan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Audra M Foshage
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Qi Sun
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Edward T Olejniczak
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Travis Clark
- VANTAGE, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Soumyadeep Dey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Shelly Lorey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bethany Alicie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gregory C Howard
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan Cawthon
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Zhongming Zhao
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Stephen W Fesik
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - William P Tansey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Aboud AA, Tidball AM, Kumar KK, Neely MD, Han B, Ess KC, Hong CC, Erikson KM, Hedera P, Bowman AB. PARK2 patient neuroprogenitors show increased mitochondrial sensitivity to copper. Neurobiol Dis 2015; 73:204-12. [PMID: 25315681 PMCID: PMC4394022 DOI: 10.1016/j.nbd.2014.10.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/26/2014] [Accepted: 10/01/2014] [Indexed: 12/21/2022] Open
Abstract
Poorly-defined interactions between environmental and genetic risk factors underlie Parkinson's disease (PD) etiology. Here we tested the hypothesis that human stem cell derived forebrain neuroprogenitors from patients with known familial risk for early onset PD will exhibit enhanced sensitivity to PD environmental risk factors compared to healthy control subjects without a family history of PD. Two male siblings (SM and PM) with biallelic loss-of-function mutations in PARK2 were identified. Human induced pluripotent stem cells (hiPSCs) from SM, PM, and four control subjects with no known family histories of PD or related neurodegenerative diseases were utilized. We tested the hypothesis that hiPSC-derived neuroprogenitors from patients with PARK2 mutations would show heightened cell death, mitochondrial dysfunction, and reactive oxygen species generation compared to control cells as a result of exposure to heavy metals (PD environmental risk factors). We report that PARK2 mutant neuroprogenitors showed increased cytotoxicity with copper (Cu) and cadmium (Cd) exposure but not manganese (Mn) or methyl mercury (MeHg) relative to control neuroprogenitors. PARK2 mutant neuroprogenitors also showed a substantial increase in mitochondrial fragmentation, initial ROS generation, and loss of mitochondrial membrane potential following Cu exposure. Our data substantiate Cu exposure as an environmental risk factor for PD. Furthermore, we report a shift in the lowest observable effect level (LOEL) for greater sensitivity to Cu-dependent mitochondrial dysfunction in patients SM and PM relative to controls, correlating with their increased genetic risk for PD.
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Affiliation(s)
- Asad A Aboud
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA
| | - Andrew M Tidball
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA
| | - Kevin K Kumar
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA
| | - M Diana Neely
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Center in Molecular Toxicology, Nashville, TN, USA
| | - Bingying Han
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA
| | - Kevin C Ess
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Center for Stem Cell Biology, Nashville, TN, USA
| | - Charles C Hong
- Vanderbilt University Medical Center, Vanderbilt Center for Stem Cell Biology, Nashville, TN, USA; Vanderbilt University Medical Center, Research Medicine, Veterans Affairs TVHS, Cardiovascular Medicine Division, Nashville, TN, USA
| | - Keith M Erikson
- University of North Carolina-Greensboro, Dept. of Nutrition, Greensboro, NC 27402-6107, USA
| | - Peter Hedera
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA
| | - Aaron B Bowman
- Vanderbilt University Medical Center, Dept. of Neurology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Kennedy Center, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Brain Institute, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Center in Molecular Toxicology, Nashville, TN, USA; Vanderbilt University Medical Center, Vanderbilt Center for Stem Cell Biology, Nashville, TN, USA.
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de Vries PJ, Whittemore VH, Leclezio L, Byars AW, Dunn D, Ess KC, Hook D, King BH, Sahin M, Jansen A. Tuberous sclerosis associated neuropsychiatric disorders (TAND) and the TAND Checklist. Pediatr Neurol 2015; 52:25-35. [PMID: 25532776 PMCID: PMC4427347 DOI: 10.1016/j.pediatrneurol.2014.10.004] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/04/2014] [Accepted: 10/07/2014] [Indexed: 11/25/2022]
Abstract
BACKGROUND Tuberous sclerosis complex is a multisystem genetic disorder with a range of physical manifestations that require evaluation, surveillance, and management. Individuals with tuberous sclerosis complex also have a range of behavioral, psychiatric, intellectual, academic, neuropsychologic, and psychosocial difficulties. These may represent the greatest burden of the disease. Around 90% of individuals with tuberous sclerosis complex will have some of these difficulties during their lifetime, yet only about 20% ever receive evaluation and treatment. The Neuropsychiatry Panel at the 2012 Tuberous Sclerosis Complex International Consensus Conference expressed concern about the significant "treatment gap" and about confusion regarding terminology relating to the biopsychosocial difficulties associated with tuberous sclerosis complex. METHODS The Tuberous Sclerosis Complex Neuropsychiatry Panel coined the term TAND-tuberous sclerosis complex-associated neuropsychiatric disorders-to bring together these multidimensional manifestations of the disorder, and recommended annual screening for TAND. In addition, the Panel agreed to develop a TAND Checklist as a guide for screening. RESULTS Here, we present an outline of the conceptualization of TAND, rationale for the structure of the TAND Checklist, and include the full US English version of the TAND Checklist. CONCLUSION We hope that the unified term TAND and the TAND Checklist will raise awareness of the importance of tuberous sclerosis complex-associated neuropsychiatric disorders and of the major burden of disease associated with it, provide a shared language and a simple tool to describe and evaluate the different levels of TAND, alert clinical teams and families or individuals of the importance of screening, assessment, and treatment of TAND, and provide a shared framework for future studies of tuberous sclerosis complex-associated neuropsychiatric disorders.
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Affiliation(s)
- Petrus J. de Vries
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa,Communications should be addressed to: Prof. de Vries; Division of Child & Adolescent Psychiatry; University of Cape Town; 46 Sawkins Road, Rondebosch; Cape Town, 7700, South Africa.
| | - Vicky H. Whittemore
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Loren Leclezio
- Division of Child & Adolescent Psychiatry, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Anna W. Byars
- Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - David Dunn
- Indiana University School of Medicine, Riley Child & Adolescent Psychiatry Clinic, Indianapolis, Indiana
| | - Kevin C. Ess
- Division of Pediatric Neurology, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dena Hook
- Tuberous Sclerosis Alliance, Silver Spring, Maryland
| | - Bryan H. King
- Department of Psychiatry and Behavioral Sciences, University of Washington & Seattle Children’s Hospital, Seattle, Washington
| | - Mustafa Sahin
- Department of Neurology, F.M. Kirby Center for Neuroscience, Boston Children’s Hospital, Boston, Maryland
| | - Anna Jansen
- Pediatric Neurology Unit, UZ Brussel, Department of Public Health, VUB, Brussels, Belgium
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Tidball AM, Bryan MR, Uhouse MA, Kumar KK, Aboud AA, Feist JE, Ess KC, Neely MD, Aschner M, Bowman AB. A novel manganese-dependent ATM-p53 signaling pathway is selectively impaired in patient-based neuroprogenitor and murine striatal models of Huntington's disease. Hum Mol Genet 2014; 24:1929-44. [PMID: 25489053 DOI: 10.1093/hmg/ddu609] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The essential micronutrient manganese is enriched in brain, especially in the basal ganglia. We sought to identify neuronal signaling pathways responsive to neurologically relevant manganese levels, as previous data suggested that alterations in striatal manganese handling occur in Huntington's disease (HD) models. We found that p53 phosphorylation at serine 15 is the most responsive cell signaling event to manganese exposure (of 18 tested) in human neuroprogenitors and a mouse striatal cell line. Manganese-dependent activation of p53 was severely diminished in HD cells. Inhibitors of ataxia telangiectasia mutated (ATM) kinase decreased manganese-dependent phosphorylation of p53. Likewise, analysis of ATM autophosphorylation and additional ATM kinase targets, H2AX and CHK2, support a role for ATM in the activation of p53 by manganese and that a defect in this process occurs in HD. Furthermore, the deficit in Mn-dependent activation of ATM kinase in HD neuroprogenitors was highly selective, as DNA damage and oxidative injury, canonical activators of ATM, did not show similar deficits. We assessed cellular manganese handling to test for correlations with the ATM-p53 pathway, and we observed reduced Mn accumulation in HD human neuroprogenitors and HD mouse striatal cells at manganese exposures associated with altered p53 activation. To determine if this phenotype contributes to the deficit in manganese-dependent ATM activation, we used pharmacological manipulation to equalize manganese levels between HD and control mouse striatal cells and rescued the ATM-p53 signaling deficit. Collectively, our data demonstrate selective alterations in manganese biology in cellular models of HD manifest in ATM-p53 signaling.
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Affiliation(s)
| | | | | | | | - Asad A Aboud
- Department of Neurology, Vanderbilt Brain Institute
| | | | - Kevin C Ess
- Department of Neurology, Vanderbilt Brain Institute, Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - M Diana Neely
- Department of Neurology, Vanderbilt Brain Institute, Vanderbilt Kennedy Center, Vanderbilt Center in Molecular Toxicology
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Aaron B Bowman
- Department of Neurology, Vanderbilt Brain Institute, Department of Pediatrics, Vanderbilt Kennedy Center, Vanderbilt Center in Molecular Toxicology, Vanderbilt Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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West JD, Austin ED, Gaskill C, Marriott S, Baskir R, Bilousova G, Jean JC, Hemnes AR, Menon S, Bloodworth NC, Fessel JP, Kropski JA, Irwin D, Ware LB, Wheeler L, Hong CC, Meyrick B, Loyd JE, Bowman AB, Ess KC, Klemm DJ, Young PP, Merryman WD, Kotton D, Majka SM. Identification of a common Wnt-associated genetic signature across multiple cell types in pulmonary arterial hypertension. Am J Physiol Cell Physiol 2014; 307:C415-30. [PMID: 24871858 DOI: 10.1152/ajpcell.00057.2014] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Understanding differences in gene expression that increase risk for pulmonary arterial hypertension (PAH) is essential to understanding the molecular basis for disease. Previous studies on patient samples were limited by end-stage disease effects or by use of nonadherent cells, which are not ideal to model vascular cells in vivo. These studies addressed the hypothesis that pathological processes associated with PAH may be identified via a genetic signature common across multiple cell types. Expression array experiments were initially conducted to analyze cell types at different stages of vascular differentiation (mesenchymal stromal and endothelial) derived from PAH patient-specific induced pluripotent stem (iPS) cells. Molecular pathways that were altered in the PAH cell lines were then compared with those in fibroblasts from 21 patients, including those with idiopathic and heritable PAH. Wnt was identified as a target pathway and was validated in vitro using primary patient mesenchymal and endothelial cells. Taken together, our data suggest that the molecular lesions that cause PAH are present in all cell types evaluated, regardless of origin, and that stimulation of the Wnt signaling pathway was a common molecular defect in both heritable and idiopathic PAH.
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Affiliation(s)
- James D West
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Vanderbilt Vascular Biology Center, Nashville, Tennessee
| | - Eric D Austin
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee
| | - Christa Gaskill
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Shennea Marriott
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Rubin Baskir
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Ganna Bilousova
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado
| | | | - Anna R Hemnes
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Vanderbilt Vascular Biology Center, Nashville, Tennessee
| | - Swapna Menon
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | | | - Joshua P Fessel
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Vanderbilt Vascular Biology Center, Nashville, Tennessee
| | - Johnathan A Kropski
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - David Irwin
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado
| | - Lorraine B Ware
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee
| | - Lisa Wheeler
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Charles C Hong
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Veterans Administration Hospital, Nashville, Tennessee
| | - Barbara Meyrick
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee
| | - James E Loyd
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Aaron B Bowman
- Department of Neurology, Vanderbilt Brain Institute, Nashville, Tennessee; Vanderbilt Center for Stem Cell Biology, Nashville, Tennessee
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee; Department of Neurology, Vanderbilt Brain Institute, Nashville, Tennessee; Vanderbilt Center for Stem Cell Biology, Nashville, Tennessee
| | - Dwight J Klemm
- Gates Center for Regenerative Medicine and Stem Cell Biology, University of Colorado, Aurora, Colorado
| | - Pampee P Young
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Stem Cell Biology, Nashville, Tennessee
| | - W David Merryman
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | | | - Susan M Majka
- Division of Allergy, Pulmonary, and Critical Care Medicine, Department of Medicine, Vanderbilt University, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Stem Cell Biology, Nashville, Tennessee; Vanderbilt Vascular Biology Center, Nashville, Tennessee; Pulmonary Vascular Research Institute, Kochi, and AnalyzeDat Consulting Services, Kerala, India; and
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35
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Srinivasakumar N, Zaboikin M, Tidball AM, Aboud AA, Neely MD, Ess KC, Bowman AB, Schuening FG. Gammaretroviral vector encoding a fluorescent marker to facilitate detection of reprogrammed human fibroblasts during iPSC generation. PeerJ 2013; 1:e224. [PMID: 24392288 PMCID: PMC3869187 DOI: 10.7717/peerj.224] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/22/2013] [Indexed: 12/23/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) are becoming mainstream tools to study mechanisms of development and disease. They have a broad range of applications in understanding disease processes, in vitro testing of novel therapies, and potential utility in regenerative medicine. Although the techniques for generating iPSCs are becoming more straightforward, scientists can expend considerable resources and time to establish this technology. A major hurdle is the accurate determination of valid iPSC-like colonies that can be selected for further cloning and characterization. In this study, we describe the use of a gammaretroviral vector encoding a fluorescent marker, mRFP1, to not only monitor the efficiency of initial transduction but also to identify putative iPSC colonies through silencing of mRFP1 gene as a consequence of successful reprogramming.
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Affiliation(s)
- Narasimhachar Srinivasakumar
- Division of Hematology/Oncology, Department of Internal Medicine, Saint Louis University , Saint Louis, MO , USA
| | - Michail Zaboikin
- Division of Hematology/Oncology, Department of Internal Medicine, Saint Louis University , Saint Louis, MO , USA
| | - Andrew M Tidball
- Vanderbilt University Medical Center, Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development , Nashville, TN , USA
| | - Asad A Aboud
- Vanderbilt University Medical Center, Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development , Nashville, TN , USA
| | - M Diana Neely
- Vanderbilt University Medical Center, Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development , Nashville, TN , USA
| | - Kevin C Ess
- Vanderbilt University Medical Center, Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development , Nashville, TN , USA
| | - Aaron B Bowman
- Vanderbilt University Medical Center, Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development , Nashville, TN , USA
| | - Friedrich G Schuening
- Division of Hematology/Oncology, Department of Internal Medicine, Saint Louis University , Saint Louis, MO , USA
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Kim SH, Kowalski ML, Carson RP, Richard Bridges L, Ess KC. Heterozygous inactivation of tsc2 enhances tumorigenesis in p53 mutant zebrafish. J Cell Sci 2013. [DOI: 10.1242/jcs.137752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
Disorders of the brain and spinal cord are common worldwide problems but have remained very difficult to treat. As a group they have diverse etiologies and can be due to trauma, infection, tumors, genetic mutations and environmental insults. Though distinct in etiology, neurological disorders share an overall intractability as current therapies are largely limited to treatment of symptoms. Improved outcomes are further constrained by the minimal endogenous capacity of the brain and spinal cord for repair. Spectacular recent scientific advances, however, suggest that new stem cell-based approaches may change this undesirable situation. In this review, I will broadly outline the challenges of studying and treating disorders of the brain and spinal cord. I will review ongoing attempts to use stem cell-based therapies to both model and treat neurological disorders. While this field is in its infancy, expected advances and needed breakthroughs point to a future where patient-derived stem cells will be the basis for the emerging discipline of regenerative neurology.
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Affiliation(s)
- Kevin C Ess
- Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Center for Stem Cell Biology, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Kim SH, Scott SA, Bennett MJ, Carson RP, Fessel J, Brown HA, Ess KC. Multi-organ abnormalities and mTORC1 activation in zebrafish model of multiple acyl-CoA dehydrogenase deficiency. PLoS Genet 2013; 9:e1003563. [PMID: 23785301 PMCID: PMC3681725 DOI: 10.1371/journal.pgen.1003563] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 04/29/2013] [Indexed: 11/23/2022] Open
Abstract
Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) is a severe mitochondrial disorder featuring multi-organ dysfunction. Mutations in either the ETFA, ETFB, and ETFDH genes can cause MADD but very little is known about disease specific mechanisms due to a paucity of animal models. We report a novel zebrafish mutant dark xavier (dxavu463) that has an inactivating mutation in the etfa gene. dxavu463 recapitulates numerous pathological and biochemical features seen in patients with MADD including brain, liver, and kidney disease. Similar to children with MADD, homozygote mutant dxavu463 zebrafish have a spectrum of phenotypes ranging from moderate to severe. Interestingly, excessive maternal feeding significantly exacerbated the phenotype. Homozygous mutant dxavu463 zebrafish have swollen and hyperplastic neural progenitor cells, hepatocytes and kidney tubule cells as well as elevations in triacylglycerol, cerebroside sulfate and cholesterol levels. Their mitochondria were also greatly enlarged, lacked normal cristae, and were dysfunctional. We also found increased signaling of the mechanistic target of rapamycin complex 1 (mTORC1) with enlarged cell size and proliferation. Treatment with rapamycin partially reversed these abnormalities. Our results indicate that etfa gene function is remarkably conserved in zebrafish as compared to humans with highly similar pathological, biochemical abnormalities to those reported in children with MADD. Altered mTORC1 signaling and maternal nutritional status may play critical roles in MADD disease progression and suggest novel treatment approaches that may ameliorate disease severity. Mitochondrial disorders have multiple genetic causes and are usually associated with severe, multi-organ disease. We report a novel zebrafish model of mitochondrial disease by inactivating the etfa gene. Loss of this gene in humans causes multiple acyl-Co dehydrogenase deficiency (MADD) that manifests with brain, liver, heart, and kidney disease. While presentations are variable, many children with MADD have a severe form of the disease that rapidly leads to death. We report that etfa gene function is highly conserved in zebrafish as compared to humans. In addition we uncovered potential disease mechanisms that were previously unknown. These include the impact of maternal nutrition on disease severity in their offspring as well as the role mTOR kinase signaling. Inhibition of this kinase with the drug rapamycin partially reversed some of the symptoms suggesting this may be a new approach to treat mitochondrial disorders.
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Affiliation(s)
- Seok-Hyung Kim
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail: (SHK); (KCE)
| | - Sarah A. Scott
- Department of Pharmacology, The Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Michael J. Bennett
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine and Children's Hospital of Philadelphia, Pennsylvania, United States of America
| | - Robert P. Carson
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Joshua Fessel
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - H. Alex Brown
- Department of Pharmacology, The Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Kevin C. Ess
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail: (SHK); (KCE)
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Fu C, Ess KC. Conditional and domain-specific inactivation of the Tsc2 gene in neural progenitor cells. Genesis 2013; 51:284-92. [PMID: 23359422 PMCID: PMC3633697 DOI: 10.1002/dvg.22377] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/16/2013] [Accepted: 01/19/2013] [Indexed: 11/11/2022]
Abstract
Tuberous sclerosis complex (TSC) is a genetic disease characterized by multiorgan benign tumors as well as neurological manifestations. Epilepsy and autism are two of the more prevalent neurological complications and are usually severe. TSC is caused by mutations in either the TSC1 (encodes hamartin) or the TSC2 (encodes tuberin) genes with TSC2 mutations being associated with worse outcomes. Tuberin contains a highly conserved GTPase-activating protein (GAP) domain that indirectly inhibits mammalian target of rapamycin complex 1 (mTORC1). mTORC1 dysregulation is currently thought to cause much of the pathogenesis in TSC but mTORC1-independent mechanisms may also contribute. We generated a novel conditional allele of Tsc2 by flanking exons 36 and 37 with loxP sites. Mice homozygous for this knock-in Tsc2 allele are viable and fertile with normal appearing growth and development. Exposure to Cre recombinase then creates an in-frame deletion involving critical residues of the GAP domain. Homozygous conditional mutant mice generated using Emx1(Cre) have increased cortical mTORC1 signaling, severe developmental brain anomalies, seizures, and die within 3 weeks. We found that the normal levels of the mutant Tsc2 mRNA, though GAP-deficient tuberin protein, appear unstable and rapidly degraded. This novel animal model will allow further study of tuberin function including the requirement of the GAP domain for protein stability.
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Affiliation(s)
- Cary Fu
- Divisions of Child Neurology and Epilepsy, Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
| | - Kevin C. Ess
- Divisions of Child Neurology and Epilepsy, Department of Neurology, Vanderbilt Kennedy Center, Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee 37232 USA
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Kim SH, Kowalski ML, Carson RP, Bridges LR, Ess KC. Heterozygous inactivation of tsc2 enhances tumorigenesis in p53 mutant zebrafish. Dis Model Mech 2013; 6:925-33. [PMID: 23580196 PMCID: PMC3701212 DOI: 10.1242/dmm.011494] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a multi-organ disorder caused by mutations of the TSC1 or TSC2 genes. A key function of these genes is to inhibit mTORC1 (mechanistic target of rapamycin complex 1) kinase signaling. Cells deficient for TSC1 or TSC2 have increased mTORC1 signaling and give rise to benign tumors, although, as a rule, true malignancies are rarely seen. In contrast, other disorders with increased mTOR signaling typically have overt malignancies. A better understanding of genetic mechanisms that govern the transformation of benign cells to malignant ones is crucial to understand cancer pathogenesis. We generated a zebrafish model of TSC and cancer progression by placing a heterozygous mutation of the tsc2 gene in a p53 mutant background. Unlike tsc2 heterozygous mutant zebrafish, which never exhibited cancers, compound tsc2;p53 mutants had malignant tumors in multiple organs. Tumorigenesis was enhanced compared with p53 mutant zebrafish. p53 mutants also had increased mTORC1 signaling that was further enhanced in tsc2;p53 compound mutants. We found increased expression of Hif1-α, Hif2-α and Vegf-c in tsc2;p53 compound mutant zebrafish compared with p53 mutant zebrafish. Expression of these proteins probably underlies the increased angiogenesis seen in compound mutant zebrafish compared with p53 mutants and might further drive cancer progression. Treatment of p53 and compound mutant zebrafish with the mTORC1 inhibitor rapamycin caused rapid shrinkage of tumor size and decreased caliber of tumor-associated blood vessels. This is the first report using an animal model to show interactions between tsc2, mTORC1 and p53 during tumorigenesis. These results might explain why individuals with TSC rarely have malignant tumors, but also suggest that cancer arising in individuals without TSC might be influenced by the status of TSC1 and/or TSC2 mutations and be potentially treatable with mTORC1 inhibitors.
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Affiliation(s)
- Seok-Hyung Kim
- Department of Neurology and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Carson RP, Fu C, Winzenburger P, Ess KC. Deletion of Rictor in neural progenitor cells reveals contributions of mTORC2 signaling to tuberous sclerosis complex. Hum Mol Genet 2013; 22:140-52. [PMID: 23049074 PMCID: PMC3522403 DOI: 10.1093/hmg/dds414] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 08/21/2012] [Accepted: 09/26/2012] [Indexed: 01/30/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a multisystem genetic disorder with severe neurologic manifestations, including epilepsy, autism, anxiety and attention deficit hyperactivity disorder. TSC is caused by the loss of either the TSC1 or TSC2 genes that normally regulate the mammalian target of rapamycin (mTOR) kinase. mTOR exists within two distinct complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). Loss of either TSC gene leads to increased mTORC1 but decreased mTORC2 signaling. As the contribution of decreased mTORC2 signaling to neural development and homeostasis has not been well studied, we generated a conditional knockout (CKO) of Rictor, a key component of mTORC2. mTORC2 signaling is impaired in the brain, whereas mTORC1 signaling is unchanged. Rictor CKO mice have small brains and bodies, normal lifespan and are fertile. Cortical layering is normal, but neurons are smaller than those in control brains. Seizures were not observed, although excessive slow activity was seen on electroencephalography. Rictor CKO mice are hyperactive and have reduced anxiety-like behavior. Finally, there is decreased white matter and increased levels of monoamine neurotransmitters in the cerebral cortex. Loss of mTORC2 signaling in the cortex independent of mTORC1 can disrupt normal brain development and function and may contribute to some of the neurologic manifestations seen in TSC.
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Affiliation(s)
| | | | | | - Kevin C. Ess
- Department of Neurology, Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, TN, USA
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Aboud AA, Tidball AM, Kumar KK, Neely MD, Ess KC, Erikson KM, Bowman AB. Genetic risk for Parkinson's disease correlates with alterations in neuronal manganese sensitivity between two human subjects. Neurotoxicology 2012; 33:1443-1449. [PMID: 23099318 DOI: 10.1016/j.neuro.2012.10.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/01/2012] [Accepted: 10/15/2012] [Indexed: 01/16/2023]
Abstract
Manganese (Mn) is an environmental risk factor for Parkinson's disease (PD). Recessive inheritance of PARK2 mutations is strongly associated with early onset PD (EOPD). It is widely assumed that the influence of PD environmental risk factors may be enhanced by the presence of PD genetic risk factors in the genetic background of individuals. However, such interactions may be difficult to predict owing to the complexities of genetic and environmental interactions. Here we examine the potential of human induced pluripotent stem (iPS) cell-derived early neural progenitor cells (NPCs) to model differences in Mn neurotoxicity between a control subject (CA) with no known PD genetic risk factors and a subject (SM) with biallelic loss-of-function mutations in PARK2 and family history of PD but no evidence of PD by neurological exam. Human iPS cells were generated from primary dermal fibroblasts of both subjects. We assessed several outcome measures associated with Mn toxicity and PD. No difference in sensitivity to Mn cytotoxicity or mitochondrial fragmentation was observed between SM and CA NPCs. However, we found that Mn exposure was associated with significantly higher reactive oxygen species (ROS) generation in SM compared to CA NPCs despite significantly less intracellular Mn accumulation. Thus, this report offers the first example of human subject-specific differences in PD-relevant environmental health related phenotypes that are consistent with pathogenic interactions between known genetic and environmental risk factors for PD.
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Affiliation(s)
- Asad A Aboud
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA
| | - Andrew M Tidball
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA; Vanderbilt Brain Institute, Nashville, TN 37232-8552, USA
| | - Kevin K Kumar
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA; Vanderbilt Brain Institute, Nashville, TN 37232-8552, USA; Vanderbilt Medical Scientist Training Program, Nashville, TN 37232-8552, USA
| | - M Diana Neely
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA; Vanderbilt Brain Institute, Nashville, TN 37232-8552, USA
| | - Kevin C Ess
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA; Vanderbilt Brain Institute, Nashville, TN 37232-8552, USA; Vanderbilt Center for Stem Cell Biology and The Department of Pediatrics, Nashville, TN 37232-8552, USA
| | - Keith M Erikson
- University of North Carolina-Greensboro, Nutrition Department, Greensboro, NC 27402-6107, USA
| | - Aaron B Bowman
- Vanderbilt University Medical Center, Department of Neurology and Vanderbilt Kennedy Center, Nashville, TN 37232-8552, USA; Vanderbilt Brain Institute, Nashville, TN 37232-8552, USA; Vanderbilt Center for Stem Cell Biology and The Department of Pediatrics, Nashville, TN 37232-8552, USA; Vanderbilt Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37232-8552, USA.
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Abstract
Tuberous sclerosis complex (TSC) is a genetic disease with severe neurologic and psychiatric manifestations including epilepsy, developmental delay, and autism. Despite much progress in defining abnormal signaling pathways including the contribution of increased mTORC1 signaling, specific abnormalities that underlie the severe neurologic features in TSC remain poorly understood. We hypothesized that epilepsy and autism in TSC result from abnormalities of γ-aminobutyric acidergic (GABAergic) interneurons. To test this hypothesis, we generated conditional knockout mice with selective deletion of the Tsc1 gene in GABAergic interneuron progenitor cells. These interneuron-specific Tsc1 conditional knockout (CKO) mice have impaired growth and decreased survival. Cortical and hippocampal GABAergic interneurons of CKO mice are enlarged and show increased mTORC1 signaling. Total numbers of GABAergic cells are reduced in the cortex with differential reduction of specific GABAergic subtypes. Ectopic clusters of cells with increased mTORC1 signaling are also seen suggesting impaired interneuron migration. The functional consequences of these cellular changes are evident in the decreased seizure threshold on exposure to the proconvulsant flurothyl. These findings support an important role for the Tsc1 gene during GABAergic interneuron development, function, and possibly migration.
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Affiliation(s)
| | | | | | | | | | - Kevin C. Ess
- Department of Neurology
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Neely MD, Litt MJ, Tidball AM, Li GG, Aboud AA, Hopkins CR, Chamberlin R, Hong CC, Ess KC, Bowman AB. DMH1, a highly selective small molecule BMP inhibitor promotes neurogenesis of hiPSCs: comparison of PAX6 and SOX1 expression during neural induction. ACS Chem Neurosci 2012; 3:482-91. [PMID: 22860217 DOI: 10.1021/cn300029t] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 03/05/2012] [Indexed: 12/25/2022] Open
Abstract
Recent successes in deriving human-induced pluripotent stem cells (hiPSCs) allow for the possibility of studying human neurons derived from patients with neurological diseases. Concomitant inhibition of the BMP and TGF-β1 branches of the TGF-β signaling pathways by the endogenous antagonist, Noggin, and the small molecule SB431542, respectively, induces efficient neuralization of hiPSCs, a method known as dual-SMAD inhibition. The use of small molecule inhibitors instead of their endogenous counterparts has several advantages including lower cost, consistent activity, and the maintenance of xeno-free culture conditions. We tested the efficacy of DMH1, a highly selective small molecule BMP-inhibitor for its potential to replace Noggin in the neuralization of hiPSCs. We compare Noggin and DMH1-induced neuralization of hiPSCs by measuring protein and mRNA levels of pluripotency and neural precursor markers over a period of seven days. The regulation of five of the six markers assessed was indistinguishable in the presence of concentrations of Noggin or DMH1 that have been shown to effectively inhibit BMP signaling in other systems. We observed that by varying the DMH1 or Noggin concentration, we could selectively modulate the number of SOX1 expressing cells, whereas PAX6, another neural precursor marker, remained the same. The level and timing of SOX1 expression have been shown to affect neural induction as well as neural lineage. Our observations, therefore, suggest that BMP-inhibitor concentrations need to be carefully monitored to ensure appropriate expression levels of all transcription factors necessary for the induction of a particular neuronal lineage. We further demonstrate that DMH1-induced neural progenitors can be differentiated into β3-tubulin expressing neurons, a subset of which also express tyrosine hydroxylase. Thus, the combined use of DMH1, a highly specific BMP-pathway inhibitor, and SB431542, a TGF-β1-pathway specific inhibitor, provides us with the tools to independently regulate these two pathways through the exclusive use of small molecule inhibitors.
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Affiliation(s)
| | | | | | | | | | | | - Reed Chamberlin
- Genetics Associates Inc., Nashville, Tennessee 37203, United States
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45
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Abstract
Tuberous sclerosis complex (TSC) is a multiorgan hamartomatous disease caused by loss of function mutations of either the TSC1 or TSC2 genes. Neurological symptoms of TSC predominate in younger patients, but renal pathologies are a serious aspect of the disease in older children and adults. To study TSC pathogenesis in the kidney, we inactivated the mouse Tsc1 gene in the distal convoluted tubules (DCT). At young ages, Tsc1 conditional knockout (CKO) mice have enlarged kidneys and mild cystogenesis with increased mammalian target of rapamycin complex (mTORC)1 but decreased mTORC2 signaling. Treatment with the mTORC1 inhibitor rapamycin reduces kidney size and cystogenesis. Rapamycin withdrawal led to massive cystogenesis involving both distal as well as proximal tubules. To assess the contribution of decreased mTORC2 signaling in kidney pathogenesis, we also generated Rictor CKO mice. These animals did not have any detectable kidney pathology. Finally, we examined primary cilia in the DCT. Cilia were longer in Tsc1 CKO mice, and rapamycin treatment returned cilia length to normal. Rictor CKO mice had normal cilia in the DCT. Overall, our findings suggest that loss of the Tsc1 gene in the DCT is sufficient for renal cystogenesis. This cytogenesis appears to be mTORC1 but not mTORC2 dependent. Intriguingly, the mechanism may be cell autonomous as well as non-cell autonomous and possibly involves the length and function of primary cilia.
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Affiliation(s)
- Eric A Armour
- Department of Neurology and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37232, USA
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Carson RP, Van Nielen DL, Winzenburger PA, Ess KC. Neuronal and glia abnormalities in Tsc1-deficient forebrain and partial rescue by rapamycin. Neurobiol Dis 2011; 45:369-80. [PMID: 21907282 DOI: 10.1016/j.nbd.2011.08.024] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 08/02/2011] [Accepted: 08/18/2011] [Indexed: 12/20/2022] Open
Abstract
Tuberous Sclerosis Complex (TSC) is a multiorgan genetic disease that prominently features brain malformations (tubers) with many patients suffering from epilepsy and autism. These malformations typically exhibit neuronal as well as glial cell abnormalities and likely underlie much of the neurological morbidity seen in TSC. Tuber pathogenesis remains poorly understood though upregulation of the mTORC1 signaling pathway in TSC has been consistently demonstrated. Here we address abnormal brain development in TSC by inactivating the mouse Tsc1 gene in embryonic neural progenitor cells. This strategy permits evaluation of the role of the Tsc1 gene in both neuronal as well as glial cell lineages. Tsc1(Emx1-Cre) conditional knockout (CKO) animals die by 25 days of life. Their brains have increased size and contain prominent large cells within the cerebral cortex that have greatly increased mTORC1 signaling and decreased mTORC2 signaling. Severe defects of cortical lamination, enlarged dysmorphic astrocytes and decreased myelination were also found. Tsc1(Emx1-Cre) CKO mice were then treated with rapamycin to see if the premature death and brain abnormalities can be rescued. Postnatal rapamycin treatment completely prevented premature death and largely reversed the glia pathology but not abnormal neuronal lamination. These findings support a model that loss of function of the TSC genes in embryonic neural progenitor cells causes cortical malformations in patients with TSC. The dramatic effect of rapamycin suggests that even with extensive multi-lineage abnormalities, a postnatal therapeutic window may exist for patients with TSC.
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Affiliation(s)
- Robert P Carson
- Department of Neurology and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA
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Kim SH, Speirs CK, Solnica-Krezel L, Ess KC. Zebrafish model of tuberous sclerosis complex reveals cell-autonomous and non-cell-autonomous functions of mutant tuberin. Dis Model Mech 2010; 4:255-67. [PMID: 20959633 PMCID: PMC3046101 DOI: 10.1242/dmm.005587] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disease caused by mutations in either the TSC1 (encodes hamartin) or TSC2 (encodes tuberin) genes. Patients with TSC have hamartomas in various organs throughout the whole body, most notably in the brain, skin, eye, heart, kidney and lung. To study the development of hamartomas, we generated a zebrafish model of TSC featuring a nonsense mutation (vu242) in the tsc2 gene. This tsc2vu242 allele encodes a truncated Tuberin protein lacking the GAP domain, which is required for inhibition of Rheb and of the TOR kinase within TORC1. We show that tsc2vu242 is a recessive larval-lethal mutation that causes increased cell size in the brain and liver. Greatly elevated TORC1 signaling is observed in tsc2vu242/vu242 homozygous zebrafish, and is moderately increased in tsc2vu242/+ heterozygotes. Forebrain neurons are poorly organized in tsc2vu242/vu242 homozygous mutants, which have extensive gray and white matter disorganization and ectopically positioned cells. Genetic mosaic analyses demonstrate that tsc2 limits TORC1 signaling in a cell-autonomous manner. However, in chimeric animals, tsc2vu242/vu242 mutant cells also mislocalize wild-type host cells in the forebrain in a non-cell-autonomous manner. These results demonstrate a highly conserved role of tsc2 in zebrafish and establish a new animal model for studies of TSC. The finding of a non-cell-autonomous function of mutant cells might help explain the formation of brain hamartomas and cortical malformations in human TSC.
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Affiliation(s)
- Seok-Hyung Kim
- Vanderbilt University, Department of Biological Sciences, Nashville, TN 37232, USA
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Abstract
Tuberous Sclerosis Complex (TSC) is a multiorgan genetic disease caused by loss of function of either the TSC1 (encodes hamartin) or TSC2 (encodes tuberin) genes. Patients with TSC have benign tumors (hamartomas) in multiple organs though brain involvement is typically the most disabling aspect of the disease as very high rates of neurodevelopmental disorders are seen. While first described well over 120 years ago, recent advances have transformed TSC into a prototypical disorder that exemplifies the methods and potential of molecular medicine. This review will detail historical aspects of TSC and its strong associations with neurodevelopmental disorders focusing on epilepsy and autism. Finally, promising new approaches for the treatment of epilepsy and autism in patients with TSC as well as those in the general population will be discussed.
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Affiliation(s)
- Kevin C Ess
- Department of Neurology, Vanderbilt Kennedy Center for Research on Human Development, Tuberous Sclerosis Clinic, Vanderbilt Children's' Hospital, Vanderbilt University, 2201 West End Avenue, Nashville, TN, 37240, USA,
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50
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Zeng LH, Ouyang Y, Gazit V, Cirrito JR, Jansen LA, Ess KC, Yamada KA, Wozniak DF, Holtzman DM, Gutmann DH, Wong M. Abnormal glutamate homeostasis and impaired synaptic plasticity and learning in a mouse model of tuberous sclerosis complex. Neurobiol Dis 2007; 28:184-96. [PMID: 17714952 PMCID: PMC2117357 DOI: 10.1016/j.nbd.2007.07.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/30/2007] [Accepted: 07/04/2007] [Indexed: 11/28/2022] Open
Abstract
Mice with inactivation of the Tuberous sclerosis complex-1 (Tsc1) gene in glia (Tsc1 GFAP CKO mice) have deficient astrocyte glutamate transporters and develop seizures, suggesting that abnormal glutamate homeostasis contributes to neurological abnormalities in these mice. We examined the hypothesis that Tsc1 GFAP CKO mice have elevated extracellular brain glutamate levels that may cause neuronal death, abnormal glutamatergic synaptic function, and associated impairments in behavioral learning. In vivo microdialysis documented elevated glutamate levels in hippocampi of Tsc1 GFAP CKO mice and several cell death assays demonstrated neuronal death in hippocampus and neocortex. Impairment of long-term potentiation (LTP) with tetanic stimulation was observed in hippocampal slices from Tsc1 GFAP CKO mice and was reversed by low concentrations of NMDA antagonist, indicating that excessive synaptic glutamate directly inhibited LTP. Finally, Tsc1 GFAP CKO mice exhibited deficits in two hippocampal-dependent learning paradigms. These results suggest that abnormal glutamate homeostasis predisposes to excitotoxic cell death, impaired synaptic plasticity and learning deficits in Tsc1 GFAP CKO mice.
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Affiliation(s)
- Ling-Hui Zeng
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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