1
|
Gordon WE, Baek S, Nguyen HP, Kuo YM, Bradley R, Fong SL, Kim N, Galazyuk A, Lee I, Ingala MR, Simmons NB, Schountz T, Cooper LN, Georgakopoulos-Soares I, Hemberg M, Ahituv N. Integrative single-cell characterization of a frugivorous and an insectivorous bat kidney and pancreas. Nat Commun 2024; 15:12. [PMID: 38195585 PMCID: PMC10776631 DOI: 10.1038/s41467-023-44186-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 12/03/2023] [Indexed: 01/11/2024] Open
Abstract
Frugivory evolved multiple times in mammals, including bats. However, the cellular and molecular components driving it remain largely unknown. Here, we use integrative single-cell sequencing (scRNA-seq and scATAC-seq) on insectivorous (Eptesicus fuscus; big brown bat) and frugivorous (Artibeus jamaicensis; Jamaican fruit bat) bat kidneys and pancreases and identify key cell population, gene expression and regulatory differences associated with the Jamaican fruit bat that also relate to human disease, particularly diabetes. We find a decrease in loop of Henle and an increase in collecting duct cells, and differentially active genes and regulatory elements involved in fluid and electrolyte balance in the Jamaican fruit bat kidney. The Jamaican fruit bat pancreas shows an increase in endocrine and a decrease in exocrine cells, and differences in genes and regulatory elements involved in insulin regulation. We also find that these frugivorous bats share several molecular characteristics with human diabetes. Combined, our work provides insights from a frugivorous mammal that could be leveraged for therapeutic purposes.
Collapse
Affiliation(s)
- Wei E Gordon
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Biology, Menlo College, 1000 El Camino Real, Atherton, CA, 94027, USA
| | - Seungbyn Baek
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hai P Nguyen
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Yien-Ming Kuo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Rachael Bradley
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Sarah L Fong
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Nayeon Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Alex Galazyuk
- Hearing Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
- POSTECH Biotech Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Melissa R Ingala
- Department of Biological Sciences, Fairleigh Dickinson University, Madison, NJ, 07940, USA
| | - Nancy B Simmons
- Division of Vertebrate Zoology, Department of Mammalogy, American Museum of Natural History, New York, NY, 10024, USA
| | - Tony Schountz
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Lisa Noelle Cooper
- Musculoskeletal Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - Ilias Georgakopoulos-Soares
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Martin Hemberg
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA.
| |
Collapse
|
2
|
Lubberding AF, Juhl CR, Skovhøj EZ, Kanters JK, Mandrup‐Poulsen T, Torekov SS. Celebrities in the heart, strangers in the pancreatic beta cell: Voltage-gated potassium channels K v 7.1 and K v 11.1 bridge long QT syndrome with hyperinsulinaemia as well as type 2 diabetes. Acta Physiol (Oxf) 2022; 234:e13781. [PMID: 34990074 PMCID: PMC9286829 DOI: 10.1111/apha.13781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/20/2021] [Accepted: 01/02/2022] [Indexed: 12/13/2022]
Abstract
Voltage‐gated potassium (Kv) channels play an important role in the repolarization of a variety of excitable tissues, including in the cardiomyocyte and the pancreatic beta cell. Recently, individuals carrying loss‐of‐function (LoF) mutations in KCNQ1, encoding Kv7.1, and KCNH2 (hERG), encoding Kv11.1, were found to exhibit post‐prandial hyperinsulinaemia and episodes of hypoglycaemia. These LoF mutations also cause the cardiac disorder long QT syndrome (LQTS), which can be aggravated by hypoglycaemia. Interestingly, patients with LQTS also have a higher burden of diabetes compared to the background population, an apparent paradox in relation to the hyperinsulinaemic phenotype, and KCNQ1 has been identified as a type 2 diabetes risk gene. This review article summarizes the involvement of delayed rectifier K+ channels in pancreatic beta cell function, with emphasis on Kv7.1 and Kv11.1, using the cardiomyocyte for context. The functional and clinical consequences of LoF mutations and polymorphisms in these channels on blood glucose homeostasis are explored using evidence from pre‐clinical, clinical and genome‐wide association studies, thereby evaluating the link between LQTS, hyperinsulinaemia and type 2 diabetes.
Collapse
Affiliation(s)
- Anniek F. Lubberding
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Christian R. Juhl
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Emil Z. Skovhøj
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Jørgen K. Kanters
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Thomas Mandrup‐Poulsen
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| | - Signe S. Torekov
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
| |
Collapse
|
3
|
Potassium channels and the development of arousal-relevant action potential trains in primary hindbrain neurons. Brain Res 2021; 1768:147574. [PMID: 34274325 DOI: 10.1016/j.brainres.2021.147574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/17/2021] [Accepted: 06/26/2021] [Indexed: 02/06/2023]
Abstract
Neurons in nucleus gigantocellularis (NGC) have been shown by many lines of evidence to be important for regulating generalized CNS arousal. Our previous study on mouse pups suggested that the development of NGC neurons' capability to fire action potential (AP) trains may both lead to the development of behavioral arousal and may itself depend on an increase in delayed rectifier currents. Here with whole-cell patch clamp we studied delayed rectifier currents in two stages. First, primary cultured neurons isolated from E12.5 embryonic hindbrain (HB), a dissection which contains all of NGC, were used to take advantage of studying neurons in vitro over using neurons in situ or in brain slices. HB neurons were tested with Guangxitoxin-1E and Resveratrol, two inhibitors of Kv2 channels which mediate the main bulk of delayed rectifier currents. Both inhibitors depressed delayed rectifier currents, but differentially: Resveratrol, but not Guangxitoxin-1E, reduced or abolished action potentials in AP trains. Since Resveratrol affects the Kv2.2 subtype, the development of the delayed rectifier mediated through Kv2.2 channels may lead to the development of HB neurons' capability to generate AP trains. Stage Two in this work found that electrophysiological properties of the primary HB neurons recorded are essentially the same as those of NGC neurons. Thus, from the two stages combined, we propose that currents mediated through Kv2.2 are crucial for generating AP trains which, in turn, lead to the development of mouse pup behavioral arousal.
Collapse
|
4
|
Martinez-Pinna J, Marroqui L, Hmadcha A, Lopez-Beas J, Soriano S, Villar-Pazos S, Alonso-Magdalena P, Dos Santos RS, Quesada I, Martin F, Soria B, Gustafsson JÅ, Nadal A. Oestrogen receptor β mediates the actions of bisphenol-A on ion channel expression in mouse pancreatic beta cells. Diabetologia 2019; 62:1667-1680. [PMID: 31250031 DOI: 10.1007/s00125-019-4925-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/26/2019] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Bisphenol-A (BPA) is a widespread endocrine-disrupting chemical that has been associated with type 2 diabetes development. Low doses of BPA modify pancreatic beta cell function and induce insulin resistance; some of these effects are mediated via activation of oestrogen receptors α (ERα) and β (ERβ). Here we investigated whether low doses of BPA regulate the expression and function of ion channel subunits involved in beta cell function. METHODS Microarray gene profiling of isolated islets from vehicle- and BPA-treated (100 μg/kg per day for 4 days) mice was performed using Affymetrix GeneChip Mouse Genome 430.2 Array. Expression level analysis was performed using the normalisation method based on the processing algorithm 'robust multi-array average'. Whole islets or dispersed islets from C57BL/6J or oestrogen receptor β (ERβ) knockout (Erβ-/-) mice were treated with vehicle or BPA (1 nmol/l) for 48 h. Whole-cell patch-clamp recordings were used to measure Na+ and K+ currents. mRNA expression was evaluated by quantitative real-time PCR. RESULTS Microarray analysis showed that BPA modulated the expression of 1440 probe sets (1192 upregulated and 248 downregulated genes). Of these, more than 50 genes, including Scn9a, Kcnb2, Kcnma1 and Kcnip1, encoded important Na+ and K+ channel subunits. These findings were confirmed by quantitative RT-PCR in islets from C57BL/6J BPA-treated mice or whole islets treated ex vivo. Electrophysiological measurements showed a decrease in both Na+ and K+ currents in BPA-treated islets. The pharmacological profile indicated that BPA reduced currents mediated by voltage-activated K+ channels (Kv2.1/2.2 channels) and large-conductance Ca2+-activated K+ channels (KCa1.1 channels), which agrees with BPA's effects on gene expression. Beta cells from ERβ-/- mice did not present BPA-induced changes, suggesting that ERβ mediates BPA's effects in pancreatic islets. Finally, BPA increased burst duration, reduced the amplitude of the action potential and enlarged the action potential half-width, leading to alteration in beta cell electrical activity. CONCLUSIONS/INTERPRETATION Our data suggest that BPA modulates the expression and function of Na+ and K+ channels via ERβ in mouse pancreatic islets. Furthermore, BPA alters beta cell electrical activity. Altogether, these BPA-induced changes in beta cells might play a role in the diabetogenic action of BPA described in animal models.
Collapse
Affiliation(s)
- Juan Martinez-Pinna
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Laura Marroqui
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Abdelkrim Hmadcha
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Javier Lopez-Beas
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Sergi Soriano
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Sabrina Villar-Pazos
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Paloma Alonso-Magdalena
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Reinaldo S Dos Santos
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Ivan Quesada
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
| | - Franz Martin
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Bernat Soria
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain
- Department of Cell Regeneration and Advanced Therapies, Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, University of Pablo Olavide-University of Seville-CSIC, Seville, Spain
| | - Jan-Åke Gustafsson
- Department of Cell Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, USA
- Department of Biosciences and Nutrition, Karolinska Institut, Huddinge, Sweden
| | - Angel Nadal
- Instituto de Biología Molecular y Celular (IBMC), Universitas Miguel Hernández, 03202, Elche, Spain.
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universitas Miguel Hernández, Elche, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain, .
| |
Collapse
|
5
|
Yoon S, Kim J, Kim SK, Baik B, Chi SM, Kim SY, Nam D. GScluster: network-weighted gene-set clustering analysis. BMC Genomics 2019; 20:352. [PMID: 31072324 PMCID: PMC6507172 DOI: 10.1186/s12864-019-5738-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Background Gene-set analysis (GSA) has been commonly used to identify significantly altered pathways or functions from omics data. However, GSA often yields a long list of gene-sets, necessitating efficient post-processing for improved interpretation. Existing methods cluster the gene-sets based on the extent of their overlap to summarize the GSA results without considering interactions between gene-sets. Results Here, we presented a novel network-weighted gene-set clustering that incorporates both the gene-set overlap and protein-protein interaction (PPI) networks. Three examples were demonstrated for microarray gene expression, GWAS summary, and RNA-sequencing data to which different GSA methods were applied. These examples as well as a global analysis show that the proposed method increases PPI densities and functional relevance of the resulting clusters. Additionally, distinct properties of gene-set distance measures were compared. The methods are implemented as an R/Shiny package GScluster that provides gene-set clustering and diverse functions for visualization of gene-sets and PPI networks. Conclusions Network-weighted gene-set clustering provides functionally more relevant gene-set clusters and related network analysis. Electronic supplementary material The online version of this article (10.1186/s12864-019-5738-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Sora Yoon
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jinhwan Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Seon-Kyu Kim
- Epigenomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.,Genome Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Bukyung Baik
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Sang-Mun Chi
- School of Computer Science and Engineering, Kyungsung University, Busan, Republic of Korea
| | - Seon-Young Kim
- Department of Functional Genomics, University of Science and Technology (UST), Daejeon, 34141, Republic of Korea. .,Genome Editing Research Center, Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea.
| | - Dougu Nam
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea. .,Department of Mathematical Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
| |
Collapse
|
6
|
Haldeman JM, Conway AE, Arlotto ME, Slentz DH, Muoio DM, Becker TC, Newgard CB. Creation of versatile cloning platforms for transgene expression and dCas9-based epigenome editing. Nucleic Acids Res 2019; 47:e23. [PMID: 30590691 PMCID: PMC6393299 DOI: 10.1093/nar/gky1286] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 12/11/2018] [Accepted: 12/16/2018] [Indexed: 01/09/2023] Open
Abstract
Genetic manipulation via transgene overexpression, RNAi, or Cas9-based methods is central to biomedical research. Unfortunately, use of these tools is often limited by vector options. We have created a modular platform (pMVP) that allows a gene of interest to be studied in the context of an array of promoters, epitope tags, conditional expression modalities, and fluorescent reporters, packaged in 35 custom destination vectors, including adenovirus, lentivirus, PiggyBac transposon, and Sleeping Beauty transposon, in aggregate >108,000 vector permutations. We also used pMVP to build an epigenetic engineering platform, pMAGIC, that packages multiple gRNAs and either Sa-dCas9 or x-dCas9(3.7) fused to one of five epigenetic modifiers. Importantly, via its compatibility with adenoviral vectors, pMAGIC uniquely enables use of dCas9/LSD1 fusions to interrogate enhancers within primary cells. To demonstrate this, we used pMAGIC to target Sa-dCas9/LSD1 and modify the epigenetic status of a conserved enhancer, resulting in altered expression of the homeobox transcription factor PDX1 and its target genes in pancreatic islets and insulinoma cells. In sum, the pMVP and pMAGIC systems empower researchers to rapidly generate purpose-built, customized vectors for manipulation of gene expression, including via targeted epigenetic modification of regulatory elements in a broad range of disease-relevant cell types.
Collapse
Affiliation(s)
- Jonathan M Haldeman
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA
| | - Amanda E Conway
- Epigenetics & Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Michelle E Arlotto
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Dorothy H Slentz
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Deborah M Muoio
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27701, USA
| | - Thomas C Becker
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27701, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA
- Department of Medicine, Duke University Medical Center, Durham, NC 27701, USA
| |
Collapse
|
7
|
White PJ, McGarrah RW, Grimsrud PA, Tso SC, Yang WH, Haldeman JM, Grenier-Larouche T, An J, Lapworth AL, Astapova I, Hannou SA, George T, Arlotto M, Olson LB, Lai M, Zhang GF, Ilkayeva O, Herman MA, Wynn RM, Chuang DT, Newgard CB. The BCKDH Kinase and Phosphatase Integrate BCAA and Lipid Metabolism via Regulation of ATP-Citrate Lyase. Cell Metab 2018; 27:1281-1293.e7. [PMID: 29779826 PMCID: PMC5990471 DOI: 10.1016/j.cmet.2018.04.015] [Citation(s) in RCA: 193] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 02/27/2018] [Accepted: 04/13/2018] [Indexed: 12/16/2022]
Abstract
Branched-chain amino acids (BCAA) are strongly associated with dysregulated glucose and lipid metabolism, but the underlying mechanisms are poorly understood. We report that inhibition of the kinase (BDK) or overexpression of the phosphatase (PPM1K) that regulates branched-chain ketoacid dehydrogenase (BCKDH), the committed step of BCAA catabolism, lowers circulating BCAA, reduces hepatic steatosis, and improves glucose tolerance in the absence of weight loss in Zucker fatty rats. Phosphoproteomics analysis identified ATP-citrate lyase (ACL) as an alternate substrate of BDK and PPM1K. Hepatic overexpression of BDK increased ACL phosphorylation and activated de novo lipogenesis. BDK and PPM1K transcript levels were increased and repressed, respectively, in response to fructose feeding or expression of the ChREBP-β transcription factor. These studies identify BDK and PPM1K as a ChREBP-regulated node that integrates BCAA and lipid metabolism. Moreover, manipulation of the BDK:PPM1K ratio relieves key metabolic disease phenotypes in a genetic model of severe obesity.
Collapse
Affiliation(s)
- Phillip J White
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA
| | - Robert W McGarrah
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA
| | - Paul A Grimsrud
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Shih-Chia Tso
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wen-Hsuan Yang
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Jonathan M Haldeman
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Thomas Grenier-Larouche
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Jie An
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Amanda L Lapworth
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Inna Astapova
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA
| | - Sarah A Hannou
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Tabitha George
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Michelle Arlotto
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Lyra B Olson
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Michelle Lai
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Guo-Fang Zhang
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA
| | - Mark A Herman
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA
| | - R Max Wynn
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David T Chuang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center & Duke Molecular Physiology Institute, Duke University Medical Center, 300 North Duke Street, Durham, NC 27701, USA; Departments of Medicine and Pharmacology & Cancer Biology, Durham, NC 27701, USA.
| |
Collapse
|
8
|
Liu T, Cheng G, Kang X, Xi Y, Zhu Y, Wang K, Sun C, Ye J, Li P, Yin H. Noninvasively evaluating the grading and IDH1 mutation status of diffuse gliomas by three-dimensional pseudo-continuous arterial spin labeling and diffusion-weighted imaging. Neuroradiology 2018; 60:693-702. [PMID: 29777252 DOI: 10.1007/s00234-018-2021-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 04/02/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE To noninvasively evaluate the value of three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) and diffusion-weighted imaging (DWI) in diffuse gliomas grading as well as isocitrate dehydrogenase (IDH) 1 mutation status. METHODS Fifty-six patients with pathologically confirmed diffuse gliomas with preoperative 3D pCASL and DWI were enrolled in this study. The Student's t test and Mann-Whitney U test were used to evaluate differences in parameters of DWI and 3D pCASL between low and high grade as well as between mutant and wild-type IDH1 diffuse gliomas; receiver operator characteristic (ROC) analysis was used to assess the diagnostic performance. Subsequently, a multivariate stepwise logistic regression analysis was used to identify the independent parameters. Besides, Kruskal-Wallis H test was used to examine the differences among grades II, III, and IV diffuse gliomas. RESULTS All parameters but CBFmean showed significant differences between low- and high-grade diffuse gliomas. In ROC analysis, the AUC of CBFmax, rCBFmean, rCBFmax, ADCmean, and ADCmin were 0.701, 0.730, 0.746, 0.810, and 0.856 respectively. Only the value of ADCmin was identified as the independent parameter in the differentiation of low- from high-grade diffuse gliomas. All parameters but CBFmean showed significant differences among the three grades. And the values of CBFmean, CBFmax, rCBFmean, and ADCmean showed significant differences between mutant and wild-type IDH1 in grade II-III astrocytoma. CONCLUSION Both 3D pCASL and DWI could be useful tools for distinguishing low- from high-grade diffuse gliomas and have the potential to differentiate different IDH1 mutation statuses of astrocytoma.
Collapse
Affiliation(s)
- Tingting Liu
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, 710032, Shaanxi, China
| | - Guang Cheng
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiaowei Kang
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, 710032, Shaanxi, China
| | - Yibin Xi
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, 710032, Shaanxi, China
| | - Yuanqiang Zhu
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, 710032, Shaanxi, China
| | - Kai Wang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chao Sun
- Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Ye
- Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ping Li
- Department of Radiology, Xi'an Mental Health Center, No. 15 Yanying Road, Xi'an, 710061, Shaanxi, China.
| | - Hong Yin
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, No. 127 Changle West Road, Xi'an, 710032, Shaanxi, China.
| |
Collapse
|
9
|
Greitzer-Antes D, Xie L, Qin T, Xie H, Zhu D, Dolai S, Liang T, Kang F, Hardy AB, He Y, Kang Y, Gaisano HY. K v2.1 clusters on β-cell plasma membrane act as reservoirs that replenish pools of newcomer insulin granule through their interaction with syntaxin-3. J Biol Chem 2018; 293:6893-6904. [PMID: 29549124 DOI: 10.1074/jbc.ra118.002703] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 03/09/2018] [Indexed: 01/22/2023] Open
Abstract
The voltage-dependent K+ (Kv) channel Kv2.1 is a major delayed rectifier in many secretory cells, including pancreatic β cells. In addition, Kv2.1 has a direct role in exocytosis at an undefined step, involving SNARE proteins, that is independent of its ion-conducting pore function. Here, we elucidated the precise step in exocytosis. We previously reported that syntaxin-3 (Syn-3) is the key syntaxin that mediates exocytosis of newcomer secretory granules that spend minimal residence time on the plasma membrane before fusion. Using high-resolution total internal reflection fluorescence microscopy, we now show that Kv2.1 forms reservoir clusters on the β-cell plasma membrane and binds Syn-3 via its C-terminal C1b domain, which recruits newcomer insulin secretory granules into this large reservoir. Upon glucose stimulation, secretory granules were released from this reservoir to replenish the pool of newcomer secretory granules for subsequent fusion, occurring just adjacent to the plasma membrane Kv2.1 clusters. C1b deletion blocked the aforementioned Kv2.1-Syn-3-mediated events and reduced fusion of newcomer secretory granules. These insights have therapeutic implications, as Kv2.1 overexpression in type-2 diabetes rat islets restored biphasic insulin secretion.
Collapse
Affiliation(s)
- Dafna Greitzer-Antes
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Li Xie
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Tairan Qin
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Huanli Xie
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Dan Zhu
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Subhankar Dolai
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Tao Liang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Fei Kang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Alexandre B Hardy
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Yan He
- the Department of Epidemiology and Health Statistics, School of Public Health and Family Medicine, Capital Medical University, Beijing 100050, China
| | - Youhou Kang
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| | - Herbert Y Gaisano
- From the Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada and
| |
Collapse
|
10
|
Fu J, Dai X, Plummer G, Suzuki K, Bautista A, Githaka JM, Senior L, Jensen M, Greitzer-Antes D, Manning Fox JE, Gaisano HY, Newgard CB, Touret N, MacDonald PE. Kv2.1 Clustering Contributes to Insulin Exocytosis and Rescues Human β-Cell Dysfunction. Diabetes 2017; 66:1890-1900. [PMID: 28607108 PMCID: PMC5482075 DOI: 10.2337/db16-1170] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 04/15/2017] [Indexed: 12/12/2022]
Abstract
Insulin exocytosis is regulated by ion channels that control excitability and Ca2+ influx. Channels also play an increasingly appreciated role in microdomain structure. In this study, we examine the mechanism by which the voltage-dependent K+ (Kv) channel Kv2.1 (KCNB1) facilitates depolarization-induced exocytosis in INS 832/13 cells and β-cells from human donors with and without type 2 diabetes (T2D). We find that Kv2.1, but not Kv2.2 (KCNB2), forms clusters of 6-12 tetrameric channels at the plasma membrane and facilitates insulin exocytosis. Knockdown of Kv2.1 expression reduces secretory granule targeting to the plasma membrane. Expression of the full-length channel (Kv2.1-wild-type) supports the glucose-dependent recruitment of secretory granules. However, a truncated channel (Kv2.1-ΔC318) that retains electrical function and syntaxin 1A binding, but lacks the ability to form clusters, does not enhance granule recruitment or exocytosis. Expression of KCNB1 appears reduced in T2D islets, and further knockdown of KCNB1 does not inhibit Kv current in T2D β-cells. Upregulation of Kv2.1-wild-type, but not Kv2.1-ΔC318, rescues the exocytotic phenotype in T2D β-cells and increases insulin secretion from T2D islets. Thus, the ability of Kv2.1 to directly facilitate insulin exocytosis depends on channel clustering. Loss of this structural role for the channel might contribute to impaired insulin secretion in diabetes.
Collapse
Affiliation(s)
- Jianyang Fu
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Xiaoqing Dai
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Gregory Plummer
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Kunimasa Suzuki
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - John M Githaka
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Laura Senior
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Mette Jensen
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Departments of Pharmacology & Cancer Biology and Medicine, Duke University, Durham, NC
| | - Dafna Greitzer-Antes
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jocelyn E Manning Fox
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Herbert Y Gaisano
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Departments of Pharmacology & Cancer Biology and Medicine, Duke University, Durham, NC
| | - Nicolas Touret
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
11
|
Hayes HL, Peterson BS, Haldeman JM, Newgard CB, Hohmeier HE, Stephens SB. Delayed apoptosis allows islet β-cells to implement an autophagic mechanism to promote cell survival. PLoS One 2017; 12:e0172567. [PMID: 28212395 PMCID: PMC5315295 DOI: 10.1371/journal.pone.0172567] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/24/2017] [Indexed: 01/09/2023] Open
Abstract
Increased β-cell death coupled with the inability to replicate existing β-cells drives the decline in β-cell mass observed in the progression of both major forms of diabetes. Understanding endogenous mechanisms of islet cell survival could have considerable value for the development of novel strategies to limit β-cell loss and thereby promote β-cell recovery. Insulinoma cells have provided useful insight into β-cell death pathways but observations made in cell lines sometimes fail to translate to primary islets. Here, we report dramatic differences in the temporal regulation and engagement of the apoptotic program in primary rodent islets relative to the INS-1 derived 832/13 cell line. As expected, 832/13 cells rapidly induced cell stress markers in response to ER stress or DNA damage and were fully committed to apoptosis, resulting in >80% cell death within 24 h. In contrast, primary rat islets were largely refractory to cell death in response to ER stress and DNA damage, despite rapid induction of stress markers, such as XBP-1(s), CHOP, and PUMA. Gene expression profiling revealed a general suppression of pro-apoptotic machinery, such as Apaf-1 and caspase 3, and sustained levels of pro-survival factors, such as cIAP-1, cIAP-2, and XIAP, in rat islets. Furthermore, we observed sustained induction of autophagy following chronic ER stress and found that inhibition of autophagy rendered islet β-cells highly vulnerable to ER stress-induced cell death. We propose that islet β-cells dampen the apoptotic response to delay the onset of cell death, providing a temporal window in which autophagy can be activated to limit cellular damage and promote survival.
Collapse
Affiliation(s)
- Heather L. Hayes
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Brett S. Peterson
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jonathan M. Haldeman
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Christopher B. Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Medicine, Division of Endocrinology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Hans E. Hohmeier
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Medicine, Division of Endocrinology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Samuel B. Stephens
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
12
|
A Pdx-1-Regulated Soluble Factor Activates Rat and Human Islet Cell Proliferation. Mol Cell Biol 2016; 36:2918-2930. [PMID: 27620967 DOI: 10.1128/mcb.00103-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 09/02/2016] [Indexed: 12/23/2022] Open
Abstract
The homeodomain transcription factor Pdx-1 has important roles in pancreas and islet development as well as in β-cell function and survival. We previously reported that Pdx-1 overexpression stimulates islet cell proliferation, but the mechanism remains unclear. Here, we demonstrate that overexpression of Pdx-1 triggers proliferation largely by a non-cell-autonomous mechanism mediated by soluble factors. Consistent with this idea, overexpression of Pdx-1 under the control of a β-cell-specific promoter (rat insulin promoter [RIP]) stimulates proliferation of both α and β cells, and overexpression of Pdx-1 in islets separated by a Transwell membrane from islets lacking Pdx-1 overexpression activates proliferation in the untreated islets. Microarray and gene ontology (GO) analysis identified inhibin beta-B (Inhbb), an activin subunit and member of the transforming growth factor β (TGF-β) superfamily, as a Pdx-1-responsive gene. Overexpression of Inhbb or addition of activin B stimulates rat islet cell and β-cell proliferation, and the activin receptors RIIA and RIIB are required for the full proliferative effects of Pdx-1 in rat islets. In human islets, Inhbb overexpression stimulates total islet cell proliferation and potentiates Pdx-1-stimulated proliferation of total islet cells and β cells. In sum, this study identifies a mechanism by which Pdx-1 induces a soluble factor that is sufficient to stimulate both rat and human islet cell proliferation.
Collapse
|
13
|
Wu Y, Shyng SL, Chen PC. Concerted Trafficking Regulation of Kv2.1 and KATP Channels by Leptin in Pancreatic β-Cells. J Biol Chem 2015; 290:29676-90. [PMID: 26453299 DOI: 10.1074/jbc.m115.670877] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 11/06/2022] Open
Abstract
In pancreatic β-cells, voltage-gated potassium 2.1 (Kv2.1) channels are the dominant delayed rectifier potassium channels responsible for action potential repolarization. Here, we report that leptin, a hormone secreted by adipocytes known to inhibit insulin secretion, causes a transient increase in surface expression of Kv2.1 channels in rodent and human β-cells. The effect of leptin on Kv2.1 surface expression is mediated by the AMP-activated protein kinase (AMPK). Activation of AMPK mimics whereas inhibition of AMPK occludes the effect of leptin. Inhibition of Ca(2+)/calmodulin-dependent protein kinase kinase β, a known upstream kinase of AMPK, also blocks the effect of leptin. In addition, the cAMP-dependent protein kinase (PKA) is involved in Kv2.1 channel trafficking regulation. Inhibition of PKA prevents leptin or AMPK activators from increasing Kv2.1 channel density, whereas stimulation of PKA is sufficient to promote Kv2.1 channel surface expression. The increased Kv2.1 surface expression by leptin is dependent on actin depolymerization, and pharmacologically induced actin depolymerization is sufficient to enhance Kv2.1 surface expression. The signaling and cellular mechanisms underlying Kv2.1 channel trafficking regulation by leptin mirror those reported recently for ATP-sensitive potassium (KATP) channels, which are critical for coupling glucose stimulation with membrane depolarization. We show that the leptin-induced increase in surface KATP channels results in more hyperpolarized membrane potentials than control cells at stimulating glucose concentrations, and the increase in Kv2.1 channels leads to a more rapid repolarization of membrane potential in cells firing action potentials. This study supports a model in which leptin exerts concerted trafficking regulation of KATP and Kv2.1 channels to coordinately inhibit insulin secretion.
Collapse
Affiliation(s)
- Yi Wu
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239 and
| | - Pei-Chun Chen
- the Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| |
Collapse
|
14
|
Sukma Rita R, Dezaki K, Kurashina T, Kakei M, Yada T. Partial blockade of Kv2.1 channel potentiates GLP-1's insulinotropic effects in islets and reduces its dose required for improving glucose tolerance in type 2 diabetic male mice. Endocrinology 2015; 156:114-23. [PMID: 25337656 DOI: 10.1210/en.2014-1728] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucagon-like peptide-1 (GLP-1)-based medicines have recently been widely used to treat type 2 diabetic patients, whereas adverse effects of nausea and vomiting have been documented. Inhibition of voltage-gated K(+) channel subtype Kv2.1 in pancreatic β-cells has been suggested to contribute to mild depolarization and promotion of insulin release. This study aimed to determine whether the blockade of Kv2.1 channels potentiates the insulinotropic effect of GLP-1 agonists. Kv2.1 channel blocker guangxitoxin-1E (GxTx) and GLP-1 agonist exendin-4 at subthreshold concentrations, when combined, markedly increased the insulin release and cytosolic Ca(2+) concentration ([Ca(2+)]i) in a glucose-dependent manner in mouse islets and β-cells. Exendin-4 at subthreshold concentration alone increased islet insulin release and β-cell [Ca(2+)]i in Kv2.1(+/-) mice. The [Ca(2+)]i response to subthreshold exendin-4 and GxTx in combination was attenuated by pretreatment with protein kinase A inhibitor H-89, indicating the protein kinase A dependency of the cooperative effect. Furthermore, subthreshold doses of GxTx and GLP-1 agonist liraglutide in combination markedly increased plasma insulin and improved glucose tolerance in diabetic db/db mice and NSY mice. These results demonstrate that a modest suppression of Kv2.1 channels dramatically raises insulinotropic potency of GLP-1-based drugs, which opens a new avenue to reduce their doses and associated adverse effects while achieving the same glycemic control in type 2 diabetes.
Collapse
Affiliation(s)
- Rauza Sukma Rita
- Division of Integrative Physiology (R.S.R., K.D., T.K., T.Y.), Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan; Department of Internal Medicine (M.K.), Saitama Medical Center, Jichi Medical University School of Medicine, Saitama 337-8503, Japan; and Department of Development Physiology (T.Y.), Division of Adaptation Development, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
| | | | | | | | | |
Collapse
|
15
|
Halban PA, Polonsky KS, Bowden DW, Hawkins MA, Ling C, Mather KJ, Powers AC, Rhodes CJ, Sussel L, Weir GC. β-cell failure in type 2 diabetes: postulated mechanisms and prospects for prevention and treatment. J Clin Endocrinol Metab 2014; 99:1983-92. [PMID: 24712577 PMCID: PMC5393482 DOI: 10.1210/jc.2014-1425] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE This article examines the foundation of β-cell failure in type 2 diabetes (T2D) and suggests areas for future research on the underlying mechanisms that may lead to improved prevention and treatment. RESEARCH DESIGN AND METHODS A group of experts participated in a conference on 14-16 October 2013 cosponsored by the Endocrine Society and the American Diabetes Association. A writing group prepared this summary and recommendations. RESULTS The writing group based this article on conference presentations, discussion, and debate. Topics covered include genetic predisposition, foundations of β-cell failure, natural history of β-cell failure, and impact of therapeutic interventions. CONCLUSIONS β-Cell failure is central to the development and progression of T2D. It antedates and predicts diabetes onset and progression, is in part genetically determined, and often can be identified with accuracy even though current tests are cumbersome and not well standardized. Multiple pathways underlie decreased β-cell function and mass, some of which may be shared and may also be a consequence of processes that initially caused dysfunction. Goals for future research include to 1) impact the natural history of β-cell failure; 2) identify and characterize genetic loci for T2D; 3) target β-cell signaling, metabolic, and genetic pathways to improve function/mass; 4) develop alternative sources of β-cells for cell-based therapy; 5) focus on metabolic environment to provide indirect benefit to β-cells; 6) improve understanding of the physiology of responses to bypass surgery; and 7) identify circulating factors and neuronal circuits underlying the axis of communication between the brain and β-cells.
Collapse
|
16
|
Halban PA, Polonsky KS, Bowden DW, Hawkins MA, Ling C, Mather KJ, Powers AC, Rhodes CJ, Sussel L, Weir GC. β-cell failure in type 2 diabetes: postulated mechanisms and prospects for prevention and treatment. Diabetes Care 2014; 37:1751-8. [PMID: 24812433 PMCID: PMC4179518 DOI: 10.2337/dc14-0396] [Citation(s) in RCA: 323] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE This article examines the foundation of β-cell failure in type 2 diabetes (T2D) and suggests areas for future research on the underlying mechanisms that may lead to improved prevention and treatment. RESEARCH DESIGN AND METHODS A group of experts participated in a conference on 14-16 October 2013 cosponsored by the Endocrine Society and the American Diabetes Association. A writing group prepared this summary and recommendations. RESULTS The writing group based this article on conference presentations, discussion, and debate. Topics covered include genetic predisposition, foundations of β-cell failure, natural history of β-cell failure, and impact of therapeutic interventions. CONCLUSIONS β-Cell failure is central to the development and progression of T2D. It antedates and predicts diabetes onset and progression, is in part genetically determined, and often can be identified with accuracy even though current tests are cumbersome and not well standardized. Multiple pathways underlie decreased β-cell function and mass, some of which may be shared and may also be a consequence of processes that initially caused dysfunction. Goals for future research include to (1) impact the natural history of β-cell failure; (2) identify and characterize genetic loci for T2D; (3) target β-cell signaling, metabolic, and genetic pathways to improve function/mass; (4) develop alternative sources of β-cells for cell-based therapy; (5) focus on metabolic environment to provide indirect benefit to β-cells; (6) improve understanding of the physiology of responses to bypass surgery; and (7) identify circulating factors and neuronal circuits underlying the axis of communication between the brain and β-cells.
Collapse
Affiliation(s)
- Philippe A Halban
- Department of Genetic Medicine and Development, University of Geneva, Geneva, Switzerland
| | - Kenneth S Polonsky
- Department of Medicine, Section of Endocrinology, University of Chicago, Chicago, IL
| | - Donald W Bowden
- Center for Genomics and Personalized Medicine Research and Center for Diabetes Research, Wake Forest University, Winston-Salem, NC
| | - Meredith A Hawkins
- Department of Medicine (Endocrinology) and Global Diabetes Institute, Albert Einstein College of Medicine, Bronx, NY
| | - Charlotte Ling
- Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kieren J Mather
- Department of Endocrinology, Indiana University, Indianapolis, IN
| | - Alvin C Powers
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University School of Medicine, Nashville, TN
| | - Christopher J Rhodes
- Kovler Diabetes Center, Department of Medicine, University of Chicago, Chicago, IL
| | - Lori Sussel
- Naomi Berrie Diabetes Center, Columbia University, New York, NY
| | - Gordon C Weir
- Joslin Diabetes Center, Harvard Medical School, Boston, MA
| |
Collapse
|
17
|
Evolutionary analysis of voltage-gated potassium channels by Bayes method. J Mol Neurosci 2013; 53:41-9. [PMID: 24318840 DOI: 10.1007/s12031-013-0192-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/12/2013] [Indexed: 10/25/2022]
Abstract
Voltage-gated potassium channels (VGPCs) are among the most complex families of ion channels. VGPCs are distributed widely among species but their biological roles remain unclear. In this study, the evolution of VGPCs and the functions of ancestral families are determined according to phylogenetic studies. We downloaded 127 genomic data of alpha subunits and 38 genomic data of beta subunits including those from human, rat, mice, Drosophila and Puccinellia tenuiflora. The genetic neighborhood of subfamily genes was determined by neighbor-joining, minimum evolution, maximum parsimony, and Bayes methods. Data was presented as phylogenetic trees. We also detected positive selection sites by site model. New insights into the evolutionary history of the VGPC family are provided. Our assumptions are as follows: (a) KCNH subfamily is likely the most original subfamily in alpha subunit; (b) VGPCs are related to neural and cardiac systems at the earliest time; (c) KCNA4 and KCNF1 may be as ancestors; (d) abnormality in one gene may cause both cardiac and neural diseases; and (e) abnormalities in KCNH6 and KCNQ7 are more likely to cause cardiac diseases.
Collapse
|
18
|
Stefan M, Zhang W, Concepcion E, Yi Z, Tomer Y. DNA methylation profiles in type 1 diabetes twins point to strong epigenetic effects on etiology. J Autoimmun 2013; 50:33-7. [PMID: 24210274 DOI: 10.1016/j.jaut.2013.10.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/07/2013] [Accepted: 10/13/2013] [Indexed: 02/06/2023]
Abstract
Type 1 diabetes (T1D) shows ∼40% concordance rate in monozygotic twins (MZ) suggesting a role for environmental factors and/or epigenetic modifications in the etiology of the disease. The aim of our study was to dissect the contribution of epigenetic factors, particularly, DNA methylation (DNAm), to the incomplete penetrance of T1D. We performed DNAm profiling in lymphocyte cell lines from 3 monozygotic (MZ) twin pairs discordant for T1D and 6 MZ twin pairs concordant for the disease using HumanMethylation27 BeadChip. This assay assesses the methylation state of 27,578 CpG sites, mostly located within proximal promoter regions. We identified 88 CpG sites displaying significant methylation changes in all T1D-discordant MZ twin pairs. Functional annotation of the genes with distinct CpG methylation profiles in T1D samples showed differential DNAm of immune response and defense response pathways between affected and unaffected twins. Integration of DNAm data with GWAS data mapped several known T1D associated genes, HLA, INS, IL-2RB, CD226, which showed significant differences in DNAm between affected and unaffected of twins. Our findings suggest that abnormalities of DNA methylation patterns, known to regulate gene transcription, may be involved in the pathogenesis of T1D.
Collapse
Affiliation(s)
- Mihaela Stefan
- Division of Endocrinology, Mount Sinai School of Medicine, New York, NY 10029, USA; James J. Peters Veterans Administration Medical Center, Bronx, NY 10468, USA
| | - Weijia Zhang
- Department of Medicine Bioinformatics Core, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Erlinda Concepcion
- Division of Endocrinology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Zhengzi Yi
- Department of Medicine Bioinformatics Core, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Yaron Tomer
- Division of Endocrinology, Mount Sinai School of Medicine, New York, NY 10029, USA; James J. Peters Veterans Administration Medical Center, Bronx, NY 10468, USA.
| |
Collapse
|