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Jia L, Ma Y, Haywood J, Jiang L, Xue B, Shi H, Dawson PA, Yu L. NPC1L1 Deficiency Suppresses Ileal Fibroblast Growth Factor 15 Expression and Increases Bile Acid Pool Size in High-Fat-Diet-Fed Mice. Cells 2021; 10:3468. [PMID: 34943976 PMCID: PMC8700447 DOI: 10.3390/cells10123468] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 02/04/2023] Open
Abstract
Niemann-Pick C1-like 1 (NPC1L1) mediates intestinal uptake of dietary and biliary cholesterol and is the target of ezetimibe, a cholesterol absorption inhibitor used to treat hypercholesterolemia. Genetic deletion of NPC1L1 or ezetimibe treatment protects mice from high-fat diet (HFD)-induced obesity; however, the molecular mechanisms responsible for this therapeutic benefit remain unknown. A major metabolic fate of cholesterol is its conversion to bile acids. We found that NPC1L1 knockout (L1-KO) mice fed an HFD had increased energy expenditure, bile acid pool size, and fecal bile acid excretion rates. The elevated bile acid pool in the HFD-fed L1-KO mice was enriched with tauro-β-muricholic acid. These changes in the L1-KO mice were associated with reduced ileal mRNA expression of fibroblast growth factor 15 (FGF15) and increased hepatic mRNA expression of cholesterol 7α-hydroxylase (Cyp7A1) and mitochondrial sterol 27-hydroxylase (Cyp27A1). In addition, mRNA expression of the membrane bile acid receptor Takeda G protein-coupled receptor 5 (TGR5) and type 2 iodothyronine deiodinase (Dio2) were elevated in brown adipose tissue of L1-KO mice, which is known to promote energy expenditure. Thus, altered bile acid homeostasis and signaling may play a role in protecting L1-KO mice against HFD-induced obesity.
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Affiliation(s)
- Lin Jia
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; (L.J.); (Y.M.); (J.H.); (P.A.D.)
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
- Department of Biological Sciences, The University of Texas at Dallas, 800 W, Campbell Road, Richardson, TX 75080, USA
| | - Yinyan Ma
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; (L.J.); (Y.M.); (J.H.); (P.A.D.)
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Jamie Haywood
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; (L.J.); (Y.M.); (J.H.); (P.A.D.)
| | - Long Jiang
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Bingzhong Xue
- Department of Endocrinology and Metabolism, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA;
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA;
| | - Hang Shi
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA;
- Internal Medicine Section on Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Paul A. Dawson
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; (L.J.); (Y.M.); (J.H.); (P.A.D.)
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322, USA
| | - Liqing Yu
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA; (L.J.); (Y.M.); (J.H.); (P.A.D.)
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
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Hung C, Tuck E, Stubbs V, van der Lee SJ, Aalfs C, van Spaendonk R, Scheltens P, Hardy J, Holstege H, Livesey FJ. SORL1 deficiency in human excitatory neurons causes APP-dependent defects in the endolysosome-autophagy network. Cell Rep 2021; 35:109259. [PMID: 34133918 PMCID: PMC8220253 DOI: 10.1016/j.celrep.2021.109259] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 12/19/2020] [Accepted: 05/25/2021] [Indexed: 01/02/2023] Open
Abstract
Dysfunction of the endolysosomal-autophagy network is emerging as an important pathogenic process in Alzheimer's disease. Mutations in the sorting receptor-encoding gene SORL1 cause autosomal-dominant Alzheimer's disease, and SORL1 variants increase risk for late-onset AD. To understand the contribution of SORL1 mutations to AD pathogenesis, we analyze the effects of a SORL1 truncating mutation on SORL1 protein levels and endolysosome function in human neurons. We find that truncating mutation results in SORL1 haploinsufficiency and enlarged endosomes in human neurons. Analysis of isogenic SORL1 wild-type, heterozygous, and homozygous null neurons demonstrates that, whereas SORL1 haploinsufficiency results in endosome dysfunction, complete loss of SORL1 leads to additional defects in lysosome function and autophagy. Neuronal endolysosomal dysfunction caused by loss of SORL1 is relieved by extracellular antisense oligonucleotide-mediated reduction of APP protein, demonstrating that PSEN1, APP, and SORL1 act in a common pathway regulating the endolysosome system, which becomes dysfunctional in AD.
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Affiliation(s)
- Christy Hung
- UCL Great Ormond Street Institute of Child Health, Zayed Centre for Research into Rare Disease in Children, 20 Guilford Street, London WC1N 1DZ, UK
| | - Eleanor Tuck
- UCL Great Ormond Street Institute of Child Health, Zayed Centre for Research into Rare Disease in Children, 20 Guilford Street, London WC1N 1DZ, UK
| | - Victoria Stubbs
- Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Sven J van der Lee
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands; Department of Clinical Genetics, Amsterdam UMC, Amsterdam, the Netherlands; Delft Bioinformatics Lab, Delft University of Technology, Delft, the Netherlands
| | - Cora Aalfs
- Department of Clinical Genetics, Amsterdam UMC, Amsterdam, the Netherlands
| | | | - Philip Scheltens
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands
| | - John Hardy
- UK Dementia Research Institute and Department of Neurodegenerative Disease and Reta Lila Weston Institute, UCL Queen Square Institute of Neurology and UCL Movement Disorders Centre, University College London, London, UK; Institute for Advanced Study, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Henne Holstege
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam UMC, Amsterdam, the Netherlands; Department of Clinical Genetics, Amsterdam UMC, Amsterdam, the Netherlands; Delft Bioinformatics Lab, Delft University of Technology, Delft, the Netherlands
| | - Frederick J Livesey
- UCL Great Ormond Street Institute of Child Health, Zayed Centre for Research into Rare Disease in Children, 20 Guilford Street, London WC1N 1DZ, UK.
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3
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Wang C, Liu K, Cao J, Wang L, Zhao Q, Li Z, Zhang H, Chen Q, Zhao T. PINK1-mediated mitophagy maintains pluripotency through optineurin. Cell Prolif 2021; 54:e13034. [PMID: 33931895 PMCID: PMC8088463 DOI: 10.1111/cpr.13034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/25/2021] [Accepted: 03/11/2021] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Dysfunction of autophagy results in accumulation of depolarized mitochondria and breakdown of self-renewal and pluripotency in ESCs. However, the regulators that control how mitochondria are degraded by autophagy for pluripotency regulation remains largely unknown. This study aims to dissect the molecular mechanisms that regulate mitochondrial homeostasis for pluripotency regulation in mouse ESCs. MATERIALS AND METHODS Parkin+/+ and parkin-/- ESCs were established from E3.5 blastocysts of parkin+/- x parkin+/- mating mice. The pink1-/- , optn-/- and ndp52-/- ESCs were generated by CRISPR-Cas9. shRNAs were used for function loss assay of target genes. Mito-Keima, ROS and ATP detection were used to investigate the mitophagy and mitochondrial function. Western blot, Q-PCR, AP staining and teratoma formation assay were performed to evaluate the PSC stemness. RESULTS PINK1 or OPTN depletion impairs the degradation of dysfunctional mitochondria during reprogramming, and reduces the reprogramming efficiency and quality. In ESCs, PINK1 or OPTN deficiency leads to accumulation of dysfunctional mitochondria and compromised pluripotency. The defective mitochondrial homeostasis and pluripotency in pink1-/- ESCs can be compensated by gain expression of phosphomimetic Ubiquitin (Ub-S65D) together with WT or a constitutively active phosphomimetic OPTN mutant (S187D, S476D, S517D), rather than constitutively inactive OPTN (S187A, S476A, S517A) or a Ub-binding dead OPTN mutant (D477N). CONCLUSIONS The mitophagy receptor OPTN guards ESC mitochondrial homeostasis and pluripotency by scavenging damaged mitochondria through TBK1-activated OPTN binding of PINK1-phosphorylated Ubiquitin.
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Affiliation(s)
- Chaoqun Wang
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
- School of Life SciencesQufu Normal UniversityQufuChina
- Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Kun Liu
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
- Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Jiani Cao
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
| | - Liang Wang
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
- Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Qian Zhao
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
- Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Zheng Li
- Department of Digestive SystemBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
| | - Honghai Zhang
- School of Life SciencesQufu Normal UniversityQufuChina
| | - Quan Chen
- College of Life SciencesNankai UniversityTianjinChina
| | - Tongbiao Zhao
- State Key Laboratory of Stem Cell and Reproductive BiologyInstitute for Stem Cell and RegenerationInstitute of ZoologyChinese Academy of SciencesBeijingChina
- School of Life SciencesQufu Normal UniversityQufuChina
- Savaid Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
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4
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Katewa A, Suto E, Hui J, Heredia J, Liang J, Hackney J, Anderson K, Alcantar TM, Bacarro N, Dunlap D, Eastham J, Paler-Martinez A, Rairdan XY, Modrusan Z, Lee WP, Austin CD, Lafkas D, Ghilardi N. The peptide symporter SLC15a4 is essential for the development of systemic lupus erythematosus in murine models. PLoS One 2021; 16:e0244439. [PMID: 33444326 PMCID: PMC7808665 DOI: 10.1371/journal.pone.0244439] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/09/2020] [Indexed: 11/18/2022] Open
Abstract
Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease representing a serious unmet medical need. The disease is associated with the loss of self-tolerance and exaggerated B cell activation, resulting in autoantibody production and the formation of immune complexes that accumulate in the kidney, causing glomerulonephritis. TLR7, an important mediator of the innate immune response, drives the expression of type-1 interferon (IFN), which leads to expression of type-1 IFN induced genes and aggravates lupus pathology. Because the lysosomal peptide symporter slc15a4 is critically required for type-1 interferon production by pDC, and for certain B cell functions in response to TLR7 and TLR9 signals, we considered it as a potential target for pharmacological intervention in SLE. We deleted the slc15a4 gene in C57BL/6, NZB, and NZW mice and found that pristane-challenged slc15a4-/- mice in the C57BL/6 background and lupus prone slc15a4-/- NZB/W F1 mice were both completely protected from lupus like disease. In the NZB/W F1 model, protection persisted even when disease development was accelerated with an adenovirus encoding IFNα, emphasizing a broad role of slc15a4 in disease initiation. Our results establish a non-redundant function of slc15a4 in regulating both innate and adaptive components of the immune response in SLE pathobiology and suggest that it may be an attractive drug target.
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Affiliation(s)
- Arna Katewa
- Dept. Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA, United States of America
| | - Eric Suto
- Dept. Translational Immunology, Genentech, South San Francisco, CA, United States of America
| | - Jessica Hui
- Evercore ISI, New York, NY, United States of America
| | - Jose Heredia
- Dept. Immunology, Genentech, South San Francisco, CA, United States of America
| | - Jie Liang
- Dept. Molecular Oncology, Genentech, South San Francisco, CA, United States of America
| | - Jason Hackney
- Dept. Bioinformatics, Genentech, South San Francisco, CA, United States of America
| | - Keith Anderson
- Dept. Molecular Biology, Genentech, South San Francisco, CA, United States of America
| | - Tuija M. Alcantar
- Dept. Molecular Biology, Genentech, South San Francisco, CA, United States of America
| | - Natasha Bacarro
- Dept. Molecular Biology, Genentech, South San Francisco, CA, United States of America
| | - Debra Dunlap
- Dept. Pathology, Genentech, South San Francisco, CA, United States of America
| | - Jeffrey Eastham
- Dept. Pathology, Genentech, South San Francisco, CA, United States of America
| | - Andres Paler-Martinez
- Dept. Translational Immunology, Genentech, South San Francisco, CA, United States of America
| | - Xin Y. Rairdan
- gRED Animal Resources, South San Francisco, CA, United States of America
| | - Zora Modrusan
- Dept. Microchemistry, Proteomics, & Lipidomics, Genentech, South San Francisco, CA, United States of America
| | - Wyne P. Lee
- Dept. Translational Immunology, Genentech, South San Francisco, CA, United States of America
| | - Cary D. Austin
- Dept. Pathology, Genentech, South San Francisco, CA, United States of America
| | - Daniel Lafkas
- Dept. Immunology, Genentech, South San Francisco, CA, United States of America
| | - Nico Ghilardi
- DiCE Molecules, South San Francisco, CA, United States of America
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5
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Himmel NJ, Rogers RT, Redd SK, Wang Y, Blount MA. Purinergic signaling is enhanced in the absence of UT-A1 and UT-A3. Physiol Rep 2021; 9:e14636. [PMID: 33369887 PMCID: PMC7769175 DOI: 10.14814/phy2.14636] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 11/24/2022] Open
Abstract
ATP is an important paracrine regulator of renal tubular water and urea transport. The activity of P2Y2 , the predominant P2Y receptor of the medullary collecting duct, is mediated by ATP, and modulates urinary concentration. To investigate the role of purinergic signaling in the absence of urea transport in the collecting duct, we studied wild-type (WT) and UT-A1/A3 null (UT-A1/A3 KO) mice in metabolic cages to monitor urine output, and collected tissue samples for analysis. We confirmed that UT-A1/A3 KO mice are polyuric, and concurrently observed lower levels of urinary cAMP as compared to WT, despite elevated serum vasopressin (AVP) levels. Because P2Y2 inhibits AVP-stimulated transport by dampening cAMP synthesis, we suspected that, similar to other models of AVP-resistant polyuria, purinergic signaling is increased in UT-A1/A3 KO mice. In fact, we observed that both urinary ATP and purinergic-mediated prostanoid (PGE2 ) levels were elevated. Collectively, our data suggest that the reduction of medullary osmolality due to the lack of UT-A1 and UT-A3 induces an AVP-resistant polyuria that is possibly exacerbated by, or at least correlated with, enhanced purinergic signaling.
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Affiliation(s)
- Nathaniel J. Himmel
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Richard T. Rogers
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Sara K. Redd
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Yirong Wang
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Mitsi A. Blount
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
- Department of PhysiologyEmory University School of MedicineAtlantaGAUSA
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6
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Li S, Bianconi S, van der Veen JW, Do AD, Stolinski J, Cecil KM, Hannah-Shmouni F, Porter FD, Shen J. Oxidative phosphorylation in creatine transporter deficiency. NMR Biomed 2021; 34:e4419. [PMID: 32990357 PMCID: PMC7722185 DOI: 10.1002/nbm.4419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
X-linked creatine transporter deficiency (CTD) is one of the three types of cerebral creatine deficiency disorders. CTD arises from pathogenic variants in the X-linked gene SLC6A8. We report the first phosphorus (31 P) MRS study of patients with CTD, where both phosphocreatine and total creatine concentrations were found to be markedly reduced. Despite the diminished role of creatine and phosphocreatine in oxidative phosphorylation in CTD, we found no elevation of lactate or lowered pH, indicating that the brain energy supply still largely relied on oxidative metabolism. Our results suggest that mitochondrial function is a potential therapeutic target for CTD.
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Affiliation(s)
- Shizhe Li
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
| | - Simona Bianconi
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | | | - An Dang Do
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - JoEllyn Stolinski
- NMR Facility, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Kim M. Cecil
- Department of Radiology, Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Fady Hannah-Shmouni
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Forbes D. Porter
- Division of Translational Medicine, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Jun Shen
- Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD, USA
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7
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Ramachandran G, Moharir SC, Raghunand TR, Swarup G. Optineurin modulates ER stress-induced signaling pathways and cell death. Biochem Biophys Res Commun 2020; 534:297-302. [PMID: 33272572 DOI: 10.1016/j.bbrc.2020.11.091] [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] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 11/25/2020] [Indexed: 11/15/2022]
Abstract
We have investigated the physiological role of the autophagy receptor Optineurin/Optn in endoplasmic reticulum (ER) stress response using cellular and animal models. In comparison to their normal counterparts, Optn-deficient mouse embryonic fibroblasts showed significantly higher cell death and caspase-3 activation upon treatment with tunicamycin and thapsigargin, inducers of ER stress. The transcript levels of some of the genes regulated by the IRE1-XBP1 and PERK-ATF4 pathways were upregulated in Optn-deficient cells, in comparison with normal cells, upon treatment with tunicamycin, and also in the brain cortex and liver of tunicamycin treated Optn-deficient mice. Also, the basal levels of IRE1α and PERK were higher in Optn-deficient cells. These results suggest that Optn modulates ER stress-induced signaling pathways and provides protection from ER stress-induced cell death.
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Affiliation(s)
| | | | | | - Ghanshyam Swarup
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.
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8
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Cooley MM, Thomas DDH, Deans K, Peng Y, Lugea A, Pandol SJ, Puglielli L, Groblewski GE. Deficient Endoplasmic Reticulum Acetyl-CoA Import in Pancreatic Acinar Cells Leads to Chronic Pancreatitis. Cell Mol Gastroenterol Hepatol 2020; 11:725-738. [PMID: 33080365 PMCID: PMC7841443 DOI: 10.1016/j.jcmgh.2020.10.008] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/14/2020] [Accepted: 10/05/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Maintaining endoplasmic reticulum (ER) proteostasis is essential for pancreatic acinar cell function. Under conditions of severe ER stress, activation of pathogenic unfolded protein response pathways plays a central role in the development and progression of pancreatitis. Less is known, however, of the consequence of perturbing ER-associated post-translational protein modifications on pancreatic outcomes. Here, we examined the role of the ER acetyl-CoA transporter AT-1 on pancreatic homeostasis. METHODS We used an AT-1S113R/+ hypomorphic mouse model, and generated an inducible, acinar-specific, AT-1 knockout mouse model, and performed histologic and biochemical analyses to probe the effect of AT-1 loss on acinar cell physiology. RESULTS We found that AT-1 expression is down-regulated significantly during both acute and chronic pancreatitis. Furthermore, acinar-specific deletion of AT-1 in acinar cells induces chronic ER stress marked by activation of both the spliced x-box binding protein 1 and protein kinase R-like ER kinase pathways, leading to spontaneous mild/moderate chronic pancreatitis evidenced by accumulation of intracellular trypsin, immune cell infiltration, and fibrosis. Induction of acute-on-chronic pancreatitis in the AT-1 model led to acinar cell loss and glad atrophy. CONCLUSIONS These results indicate a key role for AT-1 in pancreatic acinar cell homeostasis, the unfolded protein response, and that perturbations in AT-1 function leads to pancreatic disease.
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Affiliation(s)
| | | | | | - Yajing Peng
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Aurelia Lugea
- Pancreatic Research Group, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Stephen J Pandol
- Pancreatic Research Group, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin; Geriatric Research Education Clinical Center, Veterans Affairs Medical Center, Madison, Wisconsin
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9
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Marioli C, Magliocca V, Petrini S, Niceforo A, Borghi R, Petrillo S, La Rosa P, Colasuonno F, Persichini T, Piemonte F, Massey K, Tartaglia M, Moreno S, Bertini E, Compagnucci C. Antioxidant Amelioration of Riboflavin Transporter Deficiency in Motoneurons Derived from Patient-Specific Induced Pluripotent Stem Cells. Int J Mol Sci 2020; 21:E7402. [PMID: 33036493 PMCID: PMC7582490 DOI: 10.3390/ijms21197402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial dysfunction is a key element in the pathogenesis of neurodegenerative disorders, such as riboflavin transporter deficiency (RTD). This is a rare, childhood-onset disease characterized by motoneuron degeneration and caused by mutations in SLC52A2 and SLC52A3, encoding riboflavin (RF) transporters (RFVT2 and RFVT3, respectively), resulting in muscle weakness, ponto-bulbar paralysis and sensorineural deafness. Based on previous findings, which document the contribution of oxidative stress in RTD pathogenesis, we tested possible beneficial effects of several antioxidants (Vitamin C, Idebenone, Coenzyme Q10 and EPI-743, either alone or in combination with RF) on the morphology and function of neurons derived from induced pluripotent stem cells (iPSCs) from two RTD patients. To identify possible improvement of the neuronal morphotype, neurite length was measured by confocal microscopy after β-III tubulin immunofluorescent staining. Neuronal function was evaluated by determining superoxide anion generation by MitoSOX assay and intracellular calcium (Ca2+) levels, using the Fluo-4 probe. Among the antioxidants tested, EPI-743 restored the redox status, improved neurite length and ameliorated intracellular calcium influx into RTD motoneurons. In conclusion, we suggest that antioxidant supplementation may have a role in RTD treatment.
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Affiliation(s)
- Chiara Marioli
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
| | - Valentina Magliocca
- Department of Science, University Roma Tre, 00146 Rome, Italy; (V.M.); (T.P.)
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Alessia Niceforo
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Rossella Borghi
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Sara Petrillo
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Piergiorgio La Rosa
- Department of Psychology, Division of Neuroscience, Sapienza University of Rome, 00185 Rome, Italy;
| | - Fiorella Colasuonno
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Tiziana Persichini
- Department of Science, University Roma Tre, 00146 Rome, Italy; (V.M.); (T.P.)
| | - Fiorella Piemonte
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Keith Massey
- Science Director, Cure RTD Foundation, 6228 Northaven Rd., Dallas, TX 75230, USA;
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
| | - Sandra Moreno
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Claudia Compagnucci
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
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10
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McCall AL, Dhindsa JS, Pucci LA, Kahn AF, Fusco AF, Biswas DD, Strickland LM, Tseng HC, ElMallah MK. Respiratory pathology in the Optn -/- mouse model of Amyotrophic Lateral Sclerosis. Respir Physiol Neurobiol 2020; 282:103525. [PMID: 32805420 DOI: 10.1016/j.resp.2020.103525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/19/2020] [Revised: 07/29/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disorder that results in death due to respiratory failure. Many genetic defects are associated with ALS; one such defect is a mutation in the gene encoding optineurin (OPTN). Using an optineurin null mouse (Optn-/-), we sought to characterize the impact of optineurin deficiency on respiratory neurodegeneration. Respiratory function was assessed at 6 and 12 mo of age using whole body plethysmography at baseline during normoxia (FiO2: 0.21; N2 balance) and during a respiratory challenge with hypoxia and hypercapnia (FiCO2: 0.07, FiO2: 0.10; N2 balance). Histological analyses to assess motor neuron viability and respiratory nerve integrity were performed in the medulla, cervical spinal cord, hypoglossal nerve, and phrenic nerve. Minute ventilation, peak inspiratory flow, and peak expiratory flow are significantly reduced during a respiratory challenge in 6 mo Optn-/-mice. By 12 mo, tidal volume is also significantly reduced in Optn-/- mice. Furthermore, 12mo Optn-/- mice exhibit hypoglossal motor neuron loss, phrenic and hypoglossal dysmyelination, and accumulated mitochondria in the hypoglossal nerve axons. Overall, these data indicate that Optn-/- mice display neurodegenerative respiratory dysfunction and are a useful model to study the impact of novel therapies on respiratory function for optineurin-deficient ALS patients.
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Affiliation(s)
- Angela L McCall
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Justin S Dhindsa
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Logan A Pucci
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Amanda F Kahn
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Anna F Fusco
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Debolina D Biswas
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Laura M Strickland
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA
| | - Henry C Tseng
- Duke Eye Center and Department of Ophthalmology, School of Medicine, Duke University, Durham, North Carolina 27710, USA
| | - Mai K ElMallah
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina 27710, USA.
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11
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Santander N, Lizama CO, Meky E, McKinsey GL, Jung B, Sheppard D, Betsholtz C, Arnold TD. Lack of Flvcr2 impairs brain angiogenesis without affecting the blood-brain barrier. J Clin Invest 2020; 130:4055-4068. [PMID: 32369453 PMCID: PMC7410045 DOI: 10.1172/jci136578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 01/21/2020] [Accepted: 04/22/2020] [Indexed: 12/21/2022] Open
Abstract
Fowler syndrome is a rare autosomal recessive brain vascular disorder caused by mutation in FLVCR2 in humans. The disease occurs during a critical period of brain vascular development, is characterized by glomeruloid vasculopathy and hydrocephalus, and is almost invariably prenatally fatal. Here, we sought to gain insights into the process of brain vascularization and the pathogenesis of Fowler syndrome by inactivating Flvcr2 in mice. We showed that Flvcr2 was necessary for angiogenic sprouting in the brain, but surprisingly dispensable for maintaining the blood-brain barrier. Endothelial cells lacking Flvcr2 had altered expression of angiogenic factors, failed to adopt tip cell properties, and displayed reduced sprouting, leading to vascular malformations similar to those seen in humans with Fowler syndrome. Brain hypovascularization was associated with hypoxia and tissue infarction, ultimately causing hydrocephalus and death of mutant animals. Strikingly, despite severe vascular anomalies and brain tissue infarction, the blood-brain barrier was maintained in Flvcr2 mutant mice. Our Fowler syndrome model therefore defined the pathobiology of this disease and provided new insights into brain angiogenesis by showing uncoupling of vessel morphogenesis and blood-brain barrier formation.
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Affiliation(s)
| | - Carlos O. Lizama
- Cardiovascular Research Institute, UCSF, San Francisco, California, USA
| | | | | | - Bongnam Jung
- Integrated Cardiometabolic Center, Department of Medicine, Huddinge, Karolinska Institutet, Solna, Sweden
| | - Dean Sheppard
- Department of Cell Biology, UCSF, San Francisco, California, USA
| | - Christer Betsholtz
- Integrated Cardiometabolic Center, Department of Medicine, Huddinge, Karolinska Institutet, Solna, Sweden
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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12
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Rianto F, Kuma A, Ellis CL, Hassounah F, Rodriguez EL, Wang XH, Sands JM, Klein JD. UT-A1/A3 knockout mice show reduced fibrosis following unilateral ureteral obstruction. Am J Physiol Renal Physiol 2020; 318:F1160-F1166. [PMID: 32174141 PMCID: PMC7294340 DOI: 10.1152/ajprenal.00008.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/08/2020] [Revised: 02/24/2020] [Accepted: 03/12/2020] [Indexed: 12/23/2022] Open
Abstract
Renal fibrosis is a major contributor to the development and progression of chronic kidney disease. A low-protein diet can reduce the progression of chronic kidney disease and reduce the development of renal fibrosis, although the mechanism is not well understood. Urea reabsorption into the inner medulla is regulated by inner medullary urea transporter (UT)-A1 and UT-A3. Inhibition or knockout of UT-A1/A3 will reduce interstitial urea accumulation, which may be beneficial in reducing renal fibrosis. To test this hypothesis, the effect of unilateral ureteral obstruction (UUO) was compared in wild-type (WT) and UT-A1/A3 knockout mice. UUO causes increased extracellular matrix associated with increases in transforming growth factor-β, vimentin, and α-smooth muscle actin (α-SMA). In WT mice, UUO increased the abundance of three markers of fibrosis: transforming growth factor-β, vimentin, and α-SMA. In contrast, in UT-A1/A3 knockout mice, the increase following UUO was significantly reduced. Consistent with the Western blot results, immunohistochemical staining showed that the levels of vimentin and α-SMA were increased in WT mice with UUO and that the increase was reduced in UT-A1/A3 knockout mice with UUO. Masson's trichrome staining showed increased collagen in WT mice with UUO, which was reduced in UT-A1/A3 knockout mice with UUO. We conclude that reduced UT activity reduces the severity of renal fibrosis following UUO.
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Affiliation(s)
- Fitra Rianto
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Akihiro Kuma
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Carla L Ellis
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia
| | - Faten Hassounah
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Eva L Rodriguez
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Xiaonan H Wang
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Janet D Klein
- Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
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13
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Carreau C, Lenglet T, Mosnier I, Lahlou G, Fargeot G, Weiss N, Demeret S, Salachas F, Veauville‐Merllié A, Acquaviva C, Nadjar Y. A juvenile ALS-like phenotype dramatically improved after high-dose riboflavin treatment. Ann Clin Transl Neurol 2020; 7:250-253. [PMID: 32022482 PMCID: PMC7034506 DOI: 10.1002/acn3.50977] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/16/2019] [Accepted: 12/16/2019] [Indexed: 12/12/2022] Open
Abstract
Riboflavin transporter deficiency (RTD) was recently characterized as a cause of genetic recessive childhood‐onset motor neuron disease (MND) with hearing loss, formerly described as Brown‐Vialetto‐Van‐Lear syndrome. We describe a 18‐year‐old woman with probable RTD mimicking juvenile Amyotrophic Lateral Sclerosis (ALS) who presented with an inaugural respiratory failure and moderate distal four limbs weakness. Only one heterozygous SLC52A3 mutation was detected, but presence of a sub‐clinical auditory neuropathy and dramatic improvement under high dose riboflavin argued for a RTD. As RTD probably has a larger phenotypic spectrum than expected, a high dose riboflavin trial should be discussed in young‐onset MND.
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Affiliation(s)
- Christophe Carreau
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - Timothée Lenglet
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
- Department of NeurophysiologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - Isabelle Mosnier
- Department of Otology, Auditory Implants and Skull Base SurgeryGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)ParisFrance
| | - Ghizlene Lahlou
- Department of Otology, Auditory Implants and Skull Base SurgeryGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)ParisFrance
| | - Guillaume Fargeot
- Department of NeurophysiologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - Nicolas Weiss
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - Sophie Demeret
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - François Salachas
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
| | - Alice Veauville‐Merllié
- Department of Inborn Errors of Metabolism and Neonatal ScreeningCenter of Biology and Pathology EstCHU LyonBronFrance
| | - Cécile Acquaviva
- Department of Inborn Errors of Metabolism and Neonatal ScreeningCenter of Biology and Pathology EstCHU LyonBronFrance
| | - Yann Nadjar
- Department of NeurologyGroupe Hospitalier Pitié‐Salpêtrière (AP‐HP)47‐83 Boulevard de l'Hôpital75013ParisFrance
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14
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Marcé-Grau A, Martí-Sánchez L, Baide-Mairena H, Ortigoza-Escobar JD, Pérez-Dueñas B. Genetic defects of thiamine transport and metabolism: A review of clinical phenotypes, genetics, and functional studies. J Inherit Metab Dis 2019; 42:581-597. [PMID: 31095747 DOI: 10.1002/jimd.12125] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 01/19/2023]
Abstract
Thiamine is a crucial cofactor involved in the maintenance of carbohydrate metabolism and participates in multiple cellular metabolic processes within the cytosol, mitochondria, and peroxisomes. Currently, four genetic defects have been described causing impairment of thiamine transport and metabolism: SLC19A2 dysfunction leads to diabetes mellitus, megaloblastic anemia and sensory-neural hearing loss, whereas SLC19A3, SLC25A19, and TPK1-related disorders result in recurrent encephalopathy, basal ganglia necrosis, generalized dystonia, severe disability, and early death. In order to achieve early diagnosis and treatment, biomarkers play an important role. SLC19A3 patients present a profound decrease of free-thiamine in cerebrospinal fluid (CSF) and fibroblasts. TPK1 patients show decreased concentrations of thiamine pyrophosphate in blood and muscle. Thiamine supplementation has been shown to improve diabetes and anemia control in Rogers' syndrome patients due to SLC19A2 deficiency. In a significant number of patients with SLC19A3, thiamine improves clinical outcome and survival, and prevents further metabolic crisis. In SLC25A19 and TPK1 defects, thiamine has also led to clinical stabilization in single cases. Moreover, thiamine supplementation leads to normal concentrations of free-thiamine in the CSF of SLC19A3 patients. Herein, we present a literature review of the current knowledge of the disease including related clinical phenotypes, treatment approaches, update of pathogenic variants, as well as in vitro and in vivo functional models that provide pathogenic evidence and propose mechanisms for thiamine deficiency in humans.
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Affiliation(s)
- Anna Marcé-Grau
- Pediatric Neurology Research Group, Hospital Vall d'Hebron and Research Institute (VHIR), Barcelona, Spain
| | - Laura Martí-Sánchez
- Department of Clinical Biochemistry, Hospital Sant Joan de Déu Barcelona, Barcelona, Spain
- Universitat de Barcelona, Barcelona, Spain
| | - Heidy Baide-Mairena
- Pediatric Neurology Research Group, Hospital Vall d'Hebron and Research Institute (VHIR), Barcelona, Spain
| | | | - Belén Pérez-Dueñas
- Pediatric Neurology Research Group, Hospital Vall d'Hebron and Research Institute (VHIR), Barcelona, Spain
- Centre for Biochemical Research in Rare Diseases (CIBERER), Valencia, Spain
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15
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Ito T, Yamamoto N, Nakajima S, Schaffer SW. Beta-Catenin and SMAD3 Are Associated with Skeletal Muscle Aging in the Taurine Transpoeter Knockout Mouse. Adv Exp Med Biol 2018; 975 Pt 1:497-502. [PMID: 28849477 DOI: 10.1007/978-94-024-1079-2_39] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Tissue taurine depletion mediated by knocking out the taurine transporter causes several skeletal muscle abnormalities, including acceleration of cellular aging. In the present study, we investigated the signaling pathway involved in the acceleration of skeletal muscle aging by tissue taurine depletion using the bioinformatic approach of transcriptome data. We previously performed transcriptome analysis on skeletal muscle of taurine transporter knockout (TauTKO) mice using DNA microarray. Bioinformatic analysis of transcriptome data predicted the activation of SMAD3 and β-catenin as upstream signaling molecules of cyclin-dependent kinase inhibitor 2A (CDKN2A, also called p16INK4A), which is a biomarker gene of cellular senescence. The activation of SMAD3 and β-catenin in old TauTKO muscle was verified by western blot analysis. These data indicate that SMAD3- and β-catenin-dependent induction occurs in the TauTKO mouse.
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Affiliation(s)
- Takashi Ito
- Department of Bioscience, Fukui Prefectural University, Fukui, Japan.
| | - Nao Yamamoto
- School of Pharmacy, Hyogo University of Health Sciences, Kobe, Japan
| | - Shintaro Nakajima
- School of Pharmacy, Hyogo University of Health Sciences, Kobe, Japan
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16
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Sultan M, Rao A, Elpeleg O, Vaz FM, Abu Libdeh BY, Karpen SJ, Dawson PA. Organic solute transporter-β (SLC51B) deficiency in two brothers with congenital diarrhea and features of cholestasis. Hepatology 2018; 68:590-598. [PMID: 28898457 PMCID: PMC5847420 DOI: 10.1002/hep.29516] [Citation(s) in RCA: 36] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/18/2017] [Accepted: 09/06/2017] [Indexed: 12/23/2022]
Abstract
Primary bile acid malabsorption is associated with congenital diarrhea, steatorrhea, and a block in the intestinal return of bile acids in the enterohepatic circulation. Mutations in the ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2) can cause primary bile acid malabsorption but do not appear to account for most familial cases. Another major transporter involved in the intestinal reclamation of bile acids is the heteromeric organic solute transporter alpha-beta (OSTα-OSTβ; SLC51A-SLC51B), which exports bile acid across the basolateral membrane. Here we report the first patients with OSTβ deficiency, clinically characterized by chronic diarrhea, severe fat soluble vitamin deficiency, and features of cholestatic liver disease including elevated serum gamma-glutamyltransferase activity. Whole exome sequencing revealed a homozygous single nucleotide deletion in codon 27 of SLC51B, resulting in a frameshift and premature termination at codon 50. Functional studies in transfected cells showed that the SLC51B mutation resulted in markedly reduced taurocholic acid uptake activity and reduced expression of the OSTα partner protein. CONCLUSION The findings identify OSTβ deficiency as a cause of congenital chronic diarrhea with features of cholestatic liver disease. These studies underscore OSTα-OSTβ's key role in the enterohepatic circulation of bile acids in humans. (Hepatology 2017).
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Affiliation(s)
- Mutaz Sultan
- Department of Pediatrics, Makassed Hospital, Al-Qud University, Faculty of Medicine. Mount of Olives, P.O. Box 19482, Jerusalem
| | - Anuradha Rao
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Frédéric M. Vaz
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - Bassam Y Abu Libdeh
- Department of Pediatrics, Makassed Hospital, Al-Qud University, Faculty of Medicine. Mount of Olives, P.O. Box 19482, Jerusalem
| | - Saul J. Karpen
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Paul A. Dawson
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
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17
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Bruun TUJ, Sidky S, Bandeira AO, Debray FG, Ficicioglu C, Goldstein J, Joost K, Koeberl DD, Luísa D, Nassogne MC, O'Sullivan S, Õunap K, Schulze A, van Maldergem L, Salomons GS, Mercimek-Andrews S. Treatment outcome of creatine transporter deficiency: international retrospective cohort study. Metab Brain Dis 2018; 33:875-884. [PMID: 29435807 DOI: 10.1007/s11011-018-0197-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 01/29/2018] [Indexed: 12/25/2022]
Abstract
To evaluate the outcome of current treatment for creatine transporter (CRTR) deficiency, we developed a clinical severity score and initiated an international treatment registry. An online questionnaire was completed by physicians following patients with CRTR deficiency on a treatment, including creatine and/or arginine, and/or glycine. Clinical severity score included 1) global developmental delay/intellectual disability; 2) seizures; 3) behavioural disorder. Phenotype scored 1-3 = mild; 4-6 = moderate; and 7-9 = severe. We applied the clinical severity score pre- and on-treatment. Seventeen patients, 14 males and 3 females, from 16 families were included. Four patients had severe, 6 patients had moderate, and 7 patients had a mild phenotype. The phenotype ranged from mild to severe in patients diagnosed at or before 2 years of age or older than 6 years of age. The phenotype ranged from mild to severe in patients with mildly elevated urine creatine to creatinine ratio. Fourteen patients were on the combined creatine, arginine and glycine therapy. On the combined treatment with creatine, arginine and glycine, none of the males showed either deterioration or improvements in their clinical severity score, whereas two females showed improvements in the clinical severity score. Creatine monotherapy resulted in deterioration of the clinical severity score in one male. There seems to be no correlation between phenotype and degree of elevation in urine creatine to creatinine ratio, genotype, or age at diagnosis. Combined creatine, arginine and glycine therapy might have stopped disease progression in males and improved phenotype in females.
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Affiliation(s)
- Theodora U J Bruun
- Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Sarah Sidky
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anabela O Bandeira
- Pediatrics, Metabolic Unit, Centro Materno Infantil do Norte, Centro Hospitalar do Porto, Porto, Portugal
| | | | - Can Ficicioglu
- Department of Pediatrics, Division of Human Genetics, The Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer Goldstein
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, North, USA
| | - Kairit Joost
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Dwight D Koeberl
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, North, USA
| | - Diogo Luísa
- Metabolic Unit - Child Development Center, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Marie-Cecile Nassogne
- Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Woluwe-Saint-Lambert, Belgium
| | - Siobhan O'Sullivan
- Department of Metabolic Paediatrics, Royal Hospital for Sick Children, Belfast, UK
| | - Katrin Õunap
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Andreas Schulze
- Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, ON, Canada
- Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, ON, Canada
| | | | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Saadet Mercimek-Andrews
- Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, ON, Canada.
- Institute of Medical Sciences, University of Toronto, The Hospital for Sick Children, Toronto, ON, Canada.
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18
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Bárez-López S, Obregon MJ, Bernal J, Guadaño-Ferraz A. Thyroid Hormone Economy in the Perinatal Mouse Brain: Implications for Cerebral Cortex Development. Cereb Cortex 2018; 28:1783-1793. [PMID: 28407057 DOI: 10.1093/cercor/bhx088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Indexed: 12/24/2022] Open
Abstract
Thyroid hormones (THs, T4 and the transcriptionally active hormone T3) play an essential role in neurodevelopment; however, the mechanisms underlying T3 brain delivery during mice fetal development are not well known. This work has explored the sources of brain T3 during mice fetal development using biochemical, anatomical, and molecular approaches. The findings revealed that during late gestation, a large amount of fetal brain T4 is of maternal origin. Also, in the developing mouse brain, fetal T3 content is regulated through the conversion of T4 into T3 by type-2 deiodinase (D2) activity, which is present from earlier prenatal stages. Additionally, D2 activity was found to be essential to mediate expression of T3-dependent genes in the cerebral cortex, and also necessary to generate the transient cerebral cortex hyperthyroidism present in mice lacking the TH transporter Monocarboxylate transporter 8. Notably, the gene encoding for D2 (Dio2) was mainly expressed at the blood-cerebrospinal fluid barrier (BCSFB). Overall, these data signify that T4 deiodinated by D2 may be the only source of T3 during neocortical development. We therefore propose that D2 activity at the BCSFB converts the T4 transported across the choroid plexus into T3, thus supplying the brain with active hormone to maintain TH homeostasis.
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Affiliation(s)
- Soledad Bárez-López
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), E-28029 Madrid, Spain
- Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, E-28029 Madrid, Spain
| | - Maria Jesus Obregon
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), E-28029 Madrid, Spain
| | - Juan Bernal
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), E-28029 Madrid, Spain
- Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, E-28029 Madrid, Spain
| | - Ana Guadaño-Ferraz
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), E-28029 Madrid, Spain
- Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, E-28029 Madrid, Spain
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19
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Agrawal SA, Burgoyne T, Eblimit A, Bellingham J, Parfitt DA, Lane A, Nichols R, Asomugha C, Hayes MJ, Munro PM, Xu M, Wang K, Futter CE, Li Y, Chen R, Cheetham ME. REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. Hum Mol Genet 2017; 26:2667-2677. [PMID: 28475715 PMCID: PMC5808736 DOI: 10.1093/hmg/ddx149] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [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: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
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Affiliation(s)
- Smriti A. Agrawal
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aiden Eblimit
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Chinwe Asomugha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Matthew J. Hayes
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mingchu Xu
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yumei Li
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Rui Chen
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
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20
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Zhang CZ, Chen PX, Yang L, Li W, Chang MX, Jiang HX. Coordinated Expression of acrAB-tolC and Eight Other Functional Efflux Pumps Through Activating ramA and marA in Salmonella enterica serovar Typhimurium. Microb Drug Resist 2017. [PMID: 28650690 DOI: 10.1089/mdr.2017.0086] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to determine the expression of eight other functional transporter genes upon acrAB inactivation and also the expression of acrAB when the function of eight other transporters are impaired in Salmonella enterica. We used single- or multigene deletion mutants (i.e., ΔacrA, ΔacrB, ΔtolC, ΔacrAB, ΔacrEF, ΔacrD, ΔmdsABC, ΔmdtABC, ΔemrAB, ΔmacAB, ΔmdfA, ΔmdtK, ΔacrABramA, ΔacrABmarA, and ΔacrABsoxS) and real time (RT)-PCR to quantify the expression of different pump and regulator genes; infection ability was characterized by adhesion and invasion assays. The expression of acrAB operon was increased upon acrB inactivation. Single deletion of acrA or tolC also increased expression of acrB. The deletion of acrAB increased expression of eight other functional efflux pumps genes and vice versa, in which increased expression of ramA and marA was also detected. Mutants containing single deletions of functional pump genes were attenuated in cells. In conclusion, there is a feedback mechanism that coordinates regulation of AcrAB-TolC and eight other functional efflux pumps through the global transcriptional regulators ramA and marA in S. enterica serovar Typhimurium.
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21
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Jiang T, Li Y, Layton AT, Wang W, Sun Y, Li M, Zhou H, Yang B. Generation and phenotypic analysis of mice lacking all urea transporters. Kidney Int 2017; 91:338-351. [PMID: 27914708 PMCID: PMC5423716 DOI: 10.1016/j.kint.2016.09.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [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: 04/22/2016] [Revised: 08/30/2016] [Accepted: 09/08/2016] [Indexed: 01/22/2023]
Abstract
Urea transporters (UT) are a family of transmembrane urea-selective channel proteins expressed in multiple tissues and play an important role in the urine concentrating mechanism of the mammalian kidney. UT inhibitors have diuretic activity and could be developed as novel diuretics. To determine if functional deficiency of all UTs in all tissues causes physiological abnormality, we established a novel mouse model in which all UTs were knocked out by deleting an 87 kb of DNA fragment containing most parts of Slc14a1 and Slc14a2 genes. Western blot analysis and immunofluorescence confirmed that there is no expression of urea transporter in these all-UT-knockout mice. Daily urine output was nearly 3.5-fold higher, with significantly lower urine osmolality in all-UT-knockout mice than that in wild-type mice. All-UT-knockout mice were not able to increase urinary urea concentration and osmolality after water deprivation, acute urea loading, or high protein intake. A computational model that simulated UT-knockout mouse models identified the individual contribution of each UT in urine concentrating mechanism. Knocking out all UTs also decreased the blood pressure and promoted the maturation of the male reproductive system. Thus, functional deficiency of all UTs caused a urea-selective urine-concentrating defect with little physiological abnormality in extrarenal organs.
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Affiliation(s)
- Tao Jiang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yingjie Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Anita T Layton
- Department of Mathematics, Duke University, Durham, North Carolina, USA
| | - Weiling Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Min Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Hong Zhou
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, China.
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22
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Schiff M, Veauville-Merllié A, Su CH, Tzagoloff A, Rak M, Ogier de Baulny H, Boutron A, Smedts-Walters H, Romero NB, Rigal O, Rustin P, Vianey-Saban C, Acquaviva-Bourdain C. SLC25A32 Mutations and Riboflavin-Responsive Exercise Intolerance. N Engl J Med 2016; 374:795-7. [PMID: 26933868 PMCID: PMC4867164 DOI: 10.1056/nejmc1513610] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Hélène Smedts-Walters
- University of California, San Francisco, Benioff Children's Hospital Oakland, San Francisco, CA
| | | | - Odile Rigal
- Robert-Debré University Hospital, Paris, France
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23
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Brandenstein L, Schweizer M, Sedlacik J, Fiehler J, Storch S. Lysosomal dysfunction and impaired autophagy in a novel mouse model deficient for the lysosomal membrane protein Cln7. Hum Mol Genet 2016; 25:777-91. [PMID: 26681805 DOI: 10.1093/hmg/ddv615] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/14/2015] [Indexed: 12/12/2022] Open
Abstract
CLN7 disease is an autosomal recessive, childhood-onset neurodegenerative lysosomal storage disorder caused by the defective lysosomal membrane protein CLN7. We have disrupted the Cln7/Mfsd8 gene in mice by targeted deletion of exon 2 generating a novel knockout (KO) mouse model for CLN7 disease, which recapitulates key features of human CLN7 disease pathology. Cln7 KO mice showed increased mortality and a neurological phenotype including hind limb clasping and myoclonus. Lysosomal dysfunction in the brain of mutant mice was shown by the storage of autofluorescent lipofuscin-like lipopigments, subunit c of mitochondrial ATP synthase and saposin D and increased expression of lysosomal cathepsins B, D and Z. By immunohistochemical co-stainings, increased cathepsin Z expression restricted to Cln7-deficient microglia and neurons was found. Ultrastructural analyses revealed large storage bodies in Purkinje cells of Cln7 KO mice containing inclusions composed of irregular, curvilinear and rectilinear profiles as well as fingerprint profiles. Generalized astrogliosis and microgliosis in the brain preceded neurodegeneration in the olfactory bulb, cerebral cortex and cerebellum in Cln7 KO mice. Increased levels of LC3-II and the presence of neuronal p62- and ubiquitin-positive protein aggregates suggested that impaired autophagy represents a major pathomechanism in the brain of Cln7 KO mice. The data suggest that loss of the putative lysosomal transporter Cln7 in the brain leads to lysosomal dysfunction, impaired constitutive autophagy and neurodegeneration late in disease.
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Affiliation(s)
| | | | - Jan Sedlacik
- Department of Diagnostics and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany
| | - Jens Fiehler
- Department of Diagnostics and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany
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24
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Ferrara AM, Liao XH, Ye H, Weiss RE, Dumitrescu AM, Refetoff S. The Thyroid Hormone Analog DITPA Ameliorates Metabolic Parameters of Male Mice With Mct8 Deficiency. Endocrinology 2015; 156:3889-94. [PMID: 26322373 PMCID: PMC4606752 DOI: 10.1210/en.2015-1234] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in the gene encoding the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), cause mental retardation in humans associated with a specific thyroid hormone phenotype manifesting high serum T3 and low T4 and rT3 levels. Moreover, these patients have failure to thrive, and physiological changes compatible with thyrotoxicosis. Recent studies in Mct8-deficient (Mct8KO) mice revealed that the high serum T3 causes increased energy expenditure. The TH analog, diiodothyropropionic acid (DITPA), enters cells independently of Mct8 transport and shows thyromimetic action but with a lower metabolic activity than TH. In this study DITPA was given daily ip to adult Mct8KO mice to determine its effect on thyroid tests in serum and metabolism (total energy expenditure, respiratory exchange rate, and food and water intake). In addition, we measured the expression of TH-responsive genes in the brain, liver, and muscles to assess the thyromimetic effects of DITPA. Administration of 0.3 mg DITPA per 100 g body weight to Mct8KO mice brought serum T3 levels and the metabolic parameters studied to levels observed in untreated Wt animals. Analysis of TH target genes revealed amelioration of the thyrotoxic state in liver, somewhat in the soleus, but there was no amelioration of the brain hypothyroidism. In conclusion, at the dose used, DITPA mainly ameliorated the hypermetabolism of Mct8KO mice. This thyroid hormone analog is suitable for the treatment of the hypermetabolism in patients with MCT8 deficiency, as suggested in limited preliminary human trials.
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Affiliation(s)
- Alfonso Massimiliano Ferrara
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
| | - Xiao-Hui Liao
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
| | - Honggang Ye
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
| | - Roy E Weiss
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
| | - Alexandra M Dumitrescu
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
| | - Samuel Refetoff
- Departments of Medicine (A.M.F., X.-H.L., H.Y., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637
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25
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Abstract
Cell membrane water permeability is an important determinant of epithelial fluid secretion, tissue swelling, angiogenesis, tumor spread and other biological processes. Cellular water channels, aquaporins, are important drug targets. Water permeability is generally measured from the kinetics of cell volume change in response to an osmotic gradient. Here, we developed a microfluidic platform in which cells expressing a cytoplasmic, volume-sensing fluorescent dye are rapidly subjected to an osmotic gradient by solution mixing inside a ~0.1 nL droplet surrounded by oil. The solution mixing time was <10 ms. Osmotic water permeability was deduced from a single, time-integrated fluorescence image of an observation area in which the time after mixing was determined through spatial position. Water permeability was accurately measured in aquaporin-expressing erythrocytes with half-times for osmotic equilibration down to <50 ms. Compared with conventional water permeability measurements using costly stopped-flow instrumentation, the microfluidic platform here utilizes sub-microliter blood sample volume, does not suffer from mixing artifacts, and replaces challenging kinetic measurements by single image capture using a standard laboratory fluorescence microscope.
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Affiliation(s)
- Byung-Ju Jin
- Departments of Medicine and Physiology, University of California, 1246 Health Sciences East Tower, San Francisco, CA 94143-0521, USA.
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26
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Pawaria S, Moody KL, Busto P, Nündel K, Baum R, Sharma S, Gravallese EM, Fitzgerald KA, Marshak-Rothstein A. An unexpected role for RNA-sensing toll-like receptors in a murine model of DNA accrual. Clin Exp Rheumatol 2015; 33:S70-S73. [PMID: 26457825 PMCID: PMC4731237] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES The goal of this study was to determine whether endosomal Toll-like receptors (TLRs) contribute to the clinical manifestation of systemic autoimmunity exhibited by mice that lack the lysosomal nuclease DNaseII. METHODS DNaseII/IFNaR double deficient mice were intercrossed with Unc93b13d/3d mice to generate DNaseII-/-mice with non-functional endosomal TLRs. The resulting triple deficient mice were evaluated for arthritis, autoantibody production, splenomegaly, and extramedullary haematopoiesis. B cells from both strains were evaluated for their capacity to respond to endogenous DNA by using small oligonucleotide based TLR9D ligands and a novel class of bifunctional anti-DNA antibodies. RESULTS Mice that fail to express DNaseII, IFNaR, and Unc93b1 still develop arthritis but do not make autoantibodies, develop splenomegaly, or exhibit extramedullary haematopoiesis. DNaseII-/- IFNaR-/- B cells can respond to synthetic ODNs, but not to endogenous dsDNA. CONCLUSIONS RNA-reactive TLRs, presumably TLR7, are required for autoantibody production, splenomegaly, and extramedullary haematopoiesis in the DNaseII-/- model of systemic autoimmunity.
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Affiliation(s)
- Sudesh Pawaria
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Krishna L Moody
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, and Department of Microbiology, Boston University School of Medicine, Boston, USA
| | - Patricia Busto
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Kerstin Nündel
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Rebecca Baum
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Shruti Sharma
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Ellen M Gravallese
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Katherine A Fitzgerald
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Ann Marshak-Rothstein
- Department of Medicine, University of Massachusetts School of Medicine, Worcester, MA, USA.
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27
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Menezes MP, Farrar MA, Webster R, Antony J, O'Brien K, Ouvrier R, Kiernan MC, Burns J, Vucic S. Pathophysiology of motor dysfunction in a childhood motor neuron disease caused by mutations in the riboflavin transporter. Clin Neurophysiol 2015; 127:911-918. [PMID: 26092362 DOI: 10.1016/j.clinph.2015.05.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Brown-Vialetto-Van Laere (BVVL) syndrome is a progressive motor and sensory neuronopathy secondary to mutations in SLC52A2 encoding the riboflavin transporter type 2 (RFVT2). The phenotype is characterized by early childhood onset hearing loss and sensory ataxia followed by progressive upper limb weakness, optic atrophy, bulbar weakness and respiratory failure. To gain further insight into disease pathophysiology and response to riboflavin supplementation, the present study investigated whether axonal ion channel or membrane abnormalities were a feature of BVVL. METHODS Axonal excitability studies and clinical assessments were prospectively undertaken on six patients with BVVL secondary to riboflavin transporter deficiency type 2 (age range 10-21 years) at baseline and after 12 months of riboflavin (1000 mg daily) therapy. RESULTS At baseline, depolarizing and hyperpolarizing threshold electrotonus was 'fanned out' and superexcitability was increased, while the resting current-threshold gradient and refractoriness were significantly reduced in BVVL patients when compared to controls. Mathematical modeling suggested that functional alterations of myelin underlay these findings with an increase in myelin permeability. Riboflavin therapy resulted in partial normalization of the axonal excitability findings, paralleled by maintenance of muscle strength. CONCLUSIONS The present study established that abnormalities in myelin permeability at the paranode was a feature of BVVL and were partially normalized with riboflavin therapy. SIGNIFICANCE This study reveals a novel pathophysiological process for motor nerve dysfunction in BVVL. It also indicates that nerve excitability studies may be further developed in larger cohorts as a potential biomarker to identify treatment response for BVVL patients.
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Affiliation(s)
- Manoj P Menezes
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Michelle A Farrar
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia; Neurosciences Research Australia, Sydney, Australia; Department of Neurology, Sydney Children's Hospital, Sydney, Australia.
| | - Richard Webster
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Jayne Antony
- Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Katherine O'Brien
- Department of Audiology, The Children's Hospital at Westmead, Sydney, Australia
| | - Robert Ouvrier
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Matthew C Kiernan
- Neurosciences Research Australia, Sydney, Australia; Sydney Medical School, Brain & Mind Research Institute, University of Sydney, Sydney, Australia
| | - Joshua Burns
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Paediatric Gait Analysis Service of New South Wales, Sydney Children's Hospitals Network, Sydney, Australia; Sydney Arthritis and Musculoskeletal Research Network, The University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital and Western Clinical School, University of Sydney, Sydney, Australia
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28
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Pfeiffer C, Bach M, Bauer T, Campos da Ponte J, Schömig E, Gründemann D. Knockout of the ergothioneine transporter ETT in zebrafish results in increased 8-oxoguanine levels. Free Radic Biol Med 2015; 83:178-85. [PMID: 25746775 DOI: 10.1016/j.freeradbiomed.2015.02.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/02/2015] [Accepted: 02/24/2015] [Indexed: 02/02/2023]
Abstract
Ergothioneine (ET) is a natural compound that humans and other vertebrates must absorb from dietary sources. In general, ET is considered an intracellular antioxidant. However, the precise physiological purpose of ET and the consequences of ET deficiency are still unclear. The ergothioneine transporter ETT (human gene symbol SLC22A4) is a highly specific transporter for the uptake of ET. Here, we sought to identify and knock out ETT from zebrafish (Danio rerio) to determine the function of ET. We cloned and assayed three related proteins from zebrafish, only one of which catalyzed the uptake of ET. RT-PCR analysis revealed that the protein is strongly expressed in the skin, brain, kidney, intestine, and eye. In ETT-knockout animals generated by retroviral insertion into exon 1, ET content was reduced by more than 1000-fold compared to the wild type. Thus, ETT is the sole transporter responsible for uptake of ET into zebrafish. ETT-knockout fish did not exhibit obvious differences in morphology or behavior. In whole-fish homogenates, an increase in 4-hydroxy-2,3-trans-nonenal and malondialdehyde was observed, but only after stress caused by incubation with Pb(2+) or Cu(2+). Comparison of unstressed fish at the level of small molecules by LC-MS difference shading revealed a 3.8-fold increase in 8-oxoguanine (8-oxo-7,8-dihydroguanine) in the skin of ETT-knockout animals. Our knockout represents a new model for examining the consequences of complete absence of ET. Based on the phenotype observed here, we hypothesize that the specific purpose of ET could be to eliminate singlet oxygen.
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Affiliation(s)
- Carolin Pfeiffer
- Department of Pharmacology, University of Cologne, 50931 Cologne, Germany
| | - Markus Bach
- Department of Pharmacology, University of Cologne, 50931 Cologne, Germany
| | - Tim Bauer
- Department of Pharmacology, University of Cologne, 50931 Cologne, Germany
| | | | - Edgar Schömig
- Department of Pharmacology, University of Cologne, 50931 Cologne, Germany
| | - Dirk Gründemann
- Department of Pharmacology, University of Cologne, 50931 Cologne, Germany.
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29
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Ferrara AM, Liao XH, Gil-Ibáñez P, Bernal J, Weiss RE, Dumitrescu AM, Refetoff S. Placenta passage of the thyroid hormone analog DITPA to male wild-type and Mct8-deficient mice. Endocrinology 2014; 155:4088-93. [PMID: 25051435 PMCID: PMC4164925 DOI: 10.1210/en.2014-1085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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] [Indexed: 01/03/2023]
Abstract
Monocarboxylate transporter 8 (MCT8) deficiency causes severe X-linked intellectual and neuropsychological impairment associated with abnormal thyroid function tests (TFTs) producing thyroid hormone (TH) deprivation in brain and excess in peripheral tissues. The TH analog diiodothyropropionic acid (DITPA) corrected the TFTs abnormalities and hypermetabolism of MCT8-deficient children but did not improve the neurological phenotype. The latter result was attributed to the late initiation of treatment. Therefore, we gave DITPA to pregnant mice carrying Mct8-deficient embryos to determine whether DITPA, when given prenatally, crosses the placenta and affects the serum TFTs and cerebral cortex of embryos. After depletion of the endogenous TH, Mct8-heterozygous pregnant dams carrying both wild-type (Wt) and Mct8-deficient (Mct8KO) male embryos were given DITPA. Effects were compared with those treated with levothyroxine (L-T4). With DITPA treatment, serum DITPA concentration was not different in the two genotypes, which produced equal effect on serum TSH levels in both groups of pups. In contrast, with L-T4 treatment, TSH did not normalize in Mct8KO pups whereas it did in the Wt littermates and dams despite higher concentration of serum T4. Finally, both treatments similarly modulated the expression of the TH-dependent genes Shh, Klf9, and Aldh1a3 in brain. Thus, the ability of DITPA to cross the placenta, its thyromimetic action on the expression of TH-dependent genes in brain, and its better accessibility to the pituitary than L-T4, as assessed by serum TSH, make DITPA a candidate for the prenatal treatment of MCT8 deficiency.
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Affiliation(s)
- Alfonso Massimiliano Ferrara
- Departments of Medicine (A.M.F., X.-H.L., P.G.-I., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637; and Instituto de Investigaciones Biomédicas and Center for Biomedical Research on Rare Diseases (P.G-I., J.B.), Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, 28029 Madrid, Spain
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van de Kamp JM, Mancini GM, Salomons GS. X-linked creatine transporter deficiency: clinical aspects and pathophysiology. J Inherit Metab Dis 2014; 37:715-33. [PMID: 24789340 DOI: 10.1007/s10545-014-9713-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/27/2014] [Accepted: 04/01/2014] [Indexed: 12/22/2022]
Abstract
Creatine transporter deficiency was discovered in 2001 as an X-linked cause of intellectual disability characterized by cerebral creatine deficiency. This review describes the current knowledge regarding creatine metabolism, the creatine transporter and the clinical aspects of creatine transporter deficiency. The condition mainly affects the brain while other creatine requiring organs, such as the muscles, are relatively spared. Recent studies have provided strong evidence that creatine synthesis also occurs in the brain, leading to the intriguing question of why cerebral creatine is deficient in creatine transporter deficiency. The possible mechanisms explaining the cerebral creatine deficiency are discussed. The creatine transporter knockout mouse provides a good model to study the disease. Over the past years several treatment options have been explored but no treatment has been proven effective. Understanding the pathogenesis of creatine transporter deficiency is of paramount importance in the development of an effective treatment.
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MESH Headings
- Amino Acid Metabolism, Inborn Errors/diagnosis
- Amino Acid Metabolism, Inborn Errors/drug therapy
- Amino Acid Metabolism, Inborn Errors/genetics
- Amino Acid Metabolism, Inborn Errors/pathology
- Animals
- Brain Diseases, Metabolic, Inborn/complications
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/physiopathology
- Creatine/deficiency
- Creatine/genetics
- Genetic Diseases, X-Linked/genetics
- Humans
- Intellectual Disability/etiology
- Intellectual Disability/genetics
- Membrane Transport Proteins/deficiency
- Membrane Transport Proteins/genetics
- Mental Retardation, X-Linked/complications
- Mental Retardation, X-Linked/genetics
- Mental Retardation, X-Linked/physiopathology
- Mice
- Plasma Membrane Neurotransmitter Transport Proteins/deficiency
- Plasma Membrane Neurotransmitter Transport Proteins/genetics
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Affiliation(s)
- Jiddeke M van de Kamp
- Department of Clinical Genetics, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands,
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Dunbar M, Jaggumantri S, Sargent M, Stockler-Ipsiroglu S, van Karnebeek CDM. Treatment of X-linked creatine transporter (SLC6A8) deficiency: systematic review of the literature and three new cases. Mol Genet Metab 2014; 112:259-74. [PMID: 24953403 DOI: 10.1016/j.ymgme.2014.05.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/19/2014] [Accepted: 05/19/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Creatine transporter deficiency (CTD) is an X-linked inborn error of creatine metabolism characterized by reduced intra-cerebral creatine, developmental delay/intellectual disability, (ID), behavioral disturbance, seizures, and hypotonia in individuals harboring mutations in the SLC6A8 gene. Treatment for CTD includes supplementation with creatine, either alone or in combination with creatine precursors (arginine or glycine). Unlike other disorders of creatine metabolism, the efficacy of its treatment remains controversial. METHODS We present our systematic literature review (2001-2013) comprising 7 publications (case series/reports), collectively describing 25 patients who met the inclusion criteria, and 3 additional cases treated at our institution. Definitions were established and extracted data analyzed for cognitive ability, psychiatric and behavioral disturbances, epilepsy, and cerebral proton magnetic resonance spectroscopy measurements at pre- and post-treatment. RESULTS Treatment regimens varied among the 28 cases: 2 patients received creatine-monohydrate supplementation; 7 patients received L-arginine; 2 patients received creatine-monohydrate and L-arginine; and 17 patients received a combination of creatine-monohydrate, L-arginine and glycine. Median treatment duration was 34.6 months (range 3 months-5 years). Level of evidence was IV. A total of 10 patients (36%) demonstrated response to treatment, manifested by either an increase in cerebral creatine, or improved clinical parameters. Seven of the 28 patients had quantified pre- and post-treatment creatine, and it was significantly increased post-treatment. All of the patients with increased cerebral creatine also experienced clinical improvement. In addition, the majority of patients with clinical improvement had detectable cerebral creatine prior to treatment. 90% of the patients who improved were initiated on treatment before nine years of age. CONCLUSIONS Acknowledging the limitations of this systematic review, we conclude that a proportion of CTD patients show amenability to treatment-particularly milder cases with residual brain creatine, and therefore probable residual protein function. We propose systematic screening for CTD in patients with ID, to allow early initiation of treatment, which currently comprises oral creatine, arginine and/or glycine supplementation. Standardized monitoring for safety and evaluation of treatment effects are required in all patients. This study provides effectiveness on currently available treatment, which can be used to discern effectiveness of future interventions (e.g. cyclocreatine).
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Affiliation(s)
- Mary Dunbar
- Division of Pediatric Neurology, Department of Pediatrics, BC Children's Hospital, Vancouver, Canada
| | - Sravan Jaggumantri
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada
| | - Michael Sargent
- Department of Radiology, BC Children's Hospital, Vancouver, Canada
| | - Sylvia Stockler-Ipsiroglu
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada
| | - Clara D M van Karnebeek
- Division of Biochemical Diseases, Department of Pediatrics, BC Children's Hospital, Child & Family Research Institute, University of British Columbia, Vancouver, Canada; Treatable Intellectual Disability Endeavor in British Columbia (TIDE-BC), Vancouver, Canada; Centre for Molecular Medicine and Therapeutics, Vancouver, Canada.
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Hautman ER, Kokenge AN, Udobi KC, Williams MT, Vorhees CV, Skelton MR. Female mice heterozygous for creatine transporter deficiency show moderate cognitive deficits. J Inherit Metab Dis 2014; 37:63-8. [PMID: 23716276 PMCID: PMC7025435 DOI: 10.1007/s10545-013-9619-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [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: 02/22/2013] [Revised: 04/04/2013] [Accepted: 04/30/2013] [Indexed: 11/29/2022]
Abstract
Creatine transporter (CrT) deficiency (CTD) is an X-linked disorder characterized by intellectual disability and speech delay. There have been reports that show female carriers have clinical symptoms. We have created CrT knockout (CrT(-/y)) mice in which males show severe cognitive deficits as a model of this disorder. The purpose of this study was to examine if the female carrier mice show cognitive deficits. Reductions in Cr levels as well as CrT transcript were observed in the brains of the female CrT(+/-) mice. CrT(+/-) mice show hyperactivity and increased latency to find the cued platform in the Morris water maze (MWM). CrT(+/-) female mice showed deficits in MWM hidden platform acquisition but not during reversal testing. Memory deficits on probe trials were observed during both phases. Novel object recognition memory and contextual fear memory were not affected in female CrT(+/-) mice. Female CrT(+/-) mice show moderate cognitive deficits, which is consistent with some of the human data. Female CrT(+/-) mice could prove to be beneficial in further understanding CTD and testing therapeutic approaches.
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Affiliation(s)
- Emily R Hautman
- Division of Neurology, MLC 7044 Cincinnati Children's Research Foundation, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
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Müller J, Mayerl S, Visser TJ, Darras VM, Boelen A, Frappart L, Mariotta L, Verrey F, Heuer H. Tissue-specific alterations in thyroid hormone homeostasis in combined Mct10 and Mct8 deficiency. Endocrinology 2014; 155:315-25. [PMID: 24248460 DOI: 10.1210/en.2013-1800] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The monocarboxylate transporter Mct10 (Slc16a10; T-type amino acid transporter) facilitates the cellular transport of thyroid hormone (TH) and shows an overlapping expression with the well-established TH transporter Mct8. Because Mct8 deficiency is associated with distinct tissue-specific alterations in TH transport and metabolism, we speculated that Mct10 inactivation may compromise the tissue-specific TH homeostasis as well. However, analysis of Mct10 knockout (ko) mice revealed normal serum TH levels and tissue TH content in contrast to Mct8 ko mice that are characterized by high serum T3, low serum T4, decreased brain TH content, and increased tissue TH concentrations in the liver, kidneys, and thyroid gland. Surprisingly, mice deficient in both TH transporters (Mct10/Mct8 double knockout [dko] mice) showed normal serum T4 levels in the presence of elevated serum T3, indicating that the additional inactivation of Mct10 partially rescues the phenotype of Mct8 ko mice. As a consequence of the normal serum T4, brain T4 content and hypothalamic TRH expression were found to be normalized in the Mct10/Mct8 dko mice. In contrast, the hyperthyroid situation in liver, kidneys, and thyroid gland of Mct8 ko mice was even more severe in Mct10/Mct8 dko animals, suggesting that in these organs, both transporters contribute to the TH efflux. In summary, our data indicate that Mct10 indeed participates in tissue-specific TH transport and also contributes to the generation of the unusual serum TH profile characteristic for Mct8 deficiency.
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Affiliation(s)
- Julia Müller
- Leibniz Institute for Age Research/Fritz Lipmann Institute (J.M., S.M., L.F., H.H.), Jena, Germany; Department of Internal Medicine (T.J.V.), Erasmus Medical Center, Rotterdam, The Netherlands; Laboratory of Comparative Endocrinology (V.M.D.), Biology Department, Katholieke Universiteit Leuven, Leuven, Belgium; Department of Endocrinology and Metabolism (A.B.), Academic Medical Center, Amsterdam, The Netherlands; Institute of Physiology and Zürich Center for Integrative Human Physiology (L.M., F.V.), University of Zürich, Zürich, Switzerland; and Leibniz Institute for Environmental Medicine (H.H.), Düsseldorf, Germany
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Lötsch J, Hummel T, Warskulat U, Coste O, Häussinger D, Geisslinger G, Tegeder I. Congenital taurine deficiency in mice is associated with reduced sensitivity to nociceptive chemical stimulation. Neuroscience 2013; 259:63-70. [PMID: 24321512 DOI: 10.1016/j.neuroscience.2013.11.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 11/04/2013] [Accepted: 11/20/2013] [Indexed: 01/06/2023]
Abstract
The amino acid taurine is required for development and functioning of the central and peripheral nervous system where it exerts osmoregulatory, neuromodulatory and anti-apoptotic actions. It is subject to cellular import by the taurine transporter slc6a6. Absence of the transporter and consequently, absence of taurine leads to several neurologic deficits and sensory losses. In a slc6a6 knock-out mouse model, consequences of congenital taurine deficiency were assessed in nociceptive sensory processes. The formalin assay, hot plate assay, and summated generator potentials in response to local nociceptive stimulation with gaseous CO2 were applied. Reduced responsiveness of slc6a6(-/-) mice to nociceptive stimulation was observed in particular to chemical nociceptive stimuli. Scl6a6 knock-out mice spent significantly less time licking the formalin injected paw and displayed smaller amplitudes of the nociceptive nasal mucosa potentials than wild-type mice (p=0.002 and 0.01 respectively). In contrast, withdrawal latencies on a hot plate did not significantly differ, suggesting that intracellular taurine deficits lead in particular to a hyposensitivity of nociceptive sensory neurons sensitive to noxious chemical stimulation. As hereditary absence of taurine affects biological processes of anatomical structure development, the altered nociceptive responses likely reflect consequences of compromised peripheral nervous system development.
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Affiliation(s)
- J Lötsch
- Institute of Clinical Pharmacology, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany; Fraunhofer Institute of Molecular Biology and Applied Ecology-Project Group Translational Medicine and Pharmacology (IME-TMP), Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany.
| | - T Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstr. 74, D-01307 Dresden, Germany
| | - U Warskulat
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University, Moorenstraße 5, D-40225 Düsseldorf, Germany
| | - O Coste
- Institute of Clinical Pharmacology, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - D Häussinger
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University, Moorenstraße 5, D-40225 Düsseldorf, Germany
| | - G Geisslinger
- Institute of Clinical Pharmacology, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany; Fraunhofer Institute of Molecular Biology and Applied Ecology-Project Group Translational Medicine and Pharmacology (IME-TMP), Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
| | - I Tegeder
- Institute of Clinical Pharmacology, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt am Main, Germany
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Vargas P, Farias GA, Nogales J, Prada H, Carvajal V, Barón M, Rivilla R, Martín M, Olmedilla A, Gallegos MT. Plant flavonoids target Pseudomonas syringae pv. tomato DC3000 flagella and type III secretion system. Environ Microbiol Rep 2013; 5:841-50. [PMID: 24249293 DOI: 10.1111/1758-2229.12086] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 07/10/2013] [Indexed: 05/23/2023]
Abstract
Flavonoids are among the most abundant plant secondary metabolites involved in plant protection against pathogens, but micro-organisms have developed resistance mechanisms to those compounds. We previously demonstrated that the MexAB-OprM efflux pump mediates resistance of Pseudomonas syringae pv. tomato (Pto) DC3000 to flavonoids, facilitating its survival and the colonization of the host. Here, we have shown that tomato plants respond to Pto infection producing flavonoids and other phenolic compounds. The effects of flavonoids on key traits of this model plant-pathogen bacterium have also been investigated observing that they reduce Pto swimming and swarming because of the loss of flagella, and also inhibited the expression and assembly of a functional type III secretion system. Those effects were more severe in a mutant lacking the MexAB-OprM pump. Our results suggest that flavonoids inhibit the function of the GacS/GacA two-component system, causing a depletion of rsmY RNA, therefore affecting the synthesis of two important virulence factors in Pto DC3000, flagella and the type III secretion system. These data provide new insights into the flavonoid role in the molecular dialog between host and pathogen.
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Affiliation(s)
- Paola Vargas
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
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Rodrigues TB, Ceballos A, Grijota-Martínez C, Nuñez B, Refetoff S, Cerdán S, Morte B, Bernal J. Increased oxidative metabolism and neurotransmitter cycling in the brain of mice lacking the thyroid hormone transporter SLC16A2 (MCT8). PLoS One 2013; 8:e74621. [PMID: 24098341 PMCID: PMC3788064 DOI: 10.1371/journal.pone.0074621] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/03/2013] [Indexed: 11/19/2022] Open
Abstract
Mutations of the monocarboxylate transporter 8 (MCT8) cause a severe X-linked intellectual deficit and neurological impairment. MCT8 is a specific thyroid hormone (T4 and T3) transporter and the patients also present unusual abnormalities in the serum profile of thyroid hormone concentrations due to altered secretion and metabolism of T4 and T3. Given the role of thyroid hormones in brain development, it is thought that the neurological impairment is due to restricted transport of thyroid hormones to the target neurons. In this work we have investigated cerebral metabolism in mice with Mct8 deficiency. Adult male mice were infused for 30 minutes with (1-(13)C) glucose and brain extracts prepared and analyzed by (13)C nuclear magnetic resonance spectroscopy. Genetic inactivation of Mct8 resulted in increased oxidative metabolism as reflected by increased glutamate C4 enrichment, and of glutamatergic and GABAergic neurotransmissions as observed by the increases in glutamine C4 and GABA C2 enrichments, respectively. These changes were distinct to those produced by hypothyroidism or hyperthyroidism. Similar increments in glutamate C4 enrichment and GABAergic neurotransmission were observed in the combined inactivation of Mct8 and D2, indicating that the increased neurotransmission and metabolic activity were not due to increased production of cerebral T3 by the D2-encoded type 2 deiodinase. In conclusion, Mct8 deficiency has important metabolic consequences in the brain that could not be correlated with deficiency or excess of thyroid hormone supply to the brain during adulthood.
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Affiliation(s)
- Tiago B. Rodrigues
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
- CRUK, Cambridge Institute and Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ainhoa Ceballos
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
| | - Carmen Grijota-Martínez
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
- Center for Biomedical Research on Rare Diseases, Madrid, Spain
| | - Barbara Nuñez
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
| | - Samuel Refetoff
- Departments of Medicine, Pediatrics and Genetics, University of Chicago, Chicago, Illinois, United States of America
| | - Sebastian Cerdán
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
| | - Beatriz Morte
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
- Center for Biomedical Research on Rare Diseases, Madrid, Spain
| | - Juan Bernal
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas and Universidad Autonoma de Madrid, Madrid, Spain
- Center for Biomedical Research on Rare Diseases, Madrid, Spain
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Ferrara AM, Liao XH, Gil-Ibáñez P, Marcinkowski T, Bernal J, Weiss RE, Dumitrescu AM, Refetoff S. Changes in thyroid status during perinatal development of MCT8-deficient male mice. Endocrinology 2013; 154:2533-41. [PMID: 23696569 PMCID: PMC3689279 DOI: 10.1210/en.2012-2031] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [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] [Indexed: 02/05/2023]
Abstract
Patients with the monocarboxylate transporter 8 (MCT8) deficiency syndrome present with a severe psychomotor retardation and abnormal serum thyroid hormone (TH) levels, consisting of high T(3) and low T(4) and rT(3). Mice deficient in Mct8 replicate the thyroid phenotype of patients with the MCT8 gene mutations. We analyzed the serum TH levels and action in the cerebral cortex and in the liver during the perinatal period of mice deficient in Mct8 to assess how the thyroid abnormalities of Mct8 deficiency develop and to study the thyroidal status of specific tissues. During perinatal life, the thyroid phenotype of Mct8-deficient mice is different from that of adult mice. They manifest hyperthyroxinemia at embryonic day 18 and postnatal day 0. This perinatal hyperthyroxinemia is accompanied by manifestations of TH excess as evidenced by a relative increase in the expression of genes positively regulated by T3 in both the cerebral cortex and liver. An increased tissue accumulation of T(4) and T(3) and the expression of TH alternative transporters, including Lat1, Lat2, Oatp1c1, and Oatp3a1 in the cortex and Lat2 and Oatp1b2 in the liver, suggested that Mct8 deficiency either directly interferes with tissue efflux of TH or indirectly activates other transporters to increase TH uptake. This report is the first to identify that the ontogenesis of TH abnormalities in Mct8-deficient mice manifests with TH excess in the perinatal period.
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Aouida M, Texeira MR, Thevelein JM, Poulin R, Ramotar D. Agp2, a member of the yeast amino acid permease family, positively regulates polyamine transport at the transcriptional level. PLoS One 2013; 8:e65717. [PMID: 23755272 PMCID: PMC3670898 DOI: 10.1371/journal.pone.0065717] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [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: 03/22/2013] [Accepted: 04/26/2013] [Indexed: 11/22/2022] Open
Abstract
Agp2 is a plasma membrane protein of the Saccharomyces cerevisiae amino acid transporter family, involved in high-affinity uptake of various substrates including L-carnitine and polyamines. The discovery of two high affinity polyamine permeases, Dur3 and Sam3, prompted us to investigate whether Agp2 directly transports polyamines or acts instead as a regulator. Herein, we show that neither dur3Δ nor sam3Δ single mutant is defective in polyamine transport, while the dur3Δ sam3Δ double mutant exhibits a sharp decrease in polyamine uptake and an increased resistance to polyamine toxicity similar to the agp2Δ mutant. Studies of Agp2 localization indicate that in the double mutant dur3Δ sam3Δ, Agp2-GFP remains plasma membrane-localized, even though transport of polyamines is strongly reduced. We further demonstrate that Agp2 controls the expression of several transporter genes including DUR3 and SAM3, the carnitine transporter HNM1 and several hexose, nucleoside and vitamin permease genes, in addition to SKY1 encoding a SR kinase that positively regulates low-affinity polyamine uptake. Furthermore, gene expression analysis clearly suggests that Agp2 is a strong positive regulator of additional biological processes. Collectively, our data suggest that Agp2 might respond to environmental cues and thus regulate the expression of several genes including those involved in polyamine transport.
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Affiliation(s)
- Mustapha Aouida
- Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Marta Rubio Texeira
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Leuven, Belgium
- Department of Molecular Microbiology, Flanders Institute of Biotechnology, Flanders, Belgium
| | - Johan M. Thevelein
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, Leuven, Belgium
- Department of Molecular Microbiology, Flanders Institute of Biotechnology, Flanders, Belgium
| | - Richard Poulin
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Quebec, Canada
| | - Dindial Ramotar
- Maisonneuve-Rosemont Hospital, Research Center, University of Montreal, Immunology and Oncology, Montreal, Canada
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Quiblier C, Seidl K, Roschitzki B, Zinkernagel AS, Berger-Bächi B, Senn MM. Secretome analysis defines the major role of SecDF in Staphylococcus aureus virulence. PLoS One 2013; 8:e63513. [PMID: 23658837 PMCID: PMC3643904 DOI: 10.1371/journal.pone.0063513] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/02/2013] [Indexed: 01/27/2023] Open
Abstract
The Sec pathway plays a prominent role in protein export and membrane insertion, including the secretion of major bacterial virulence determinants. The accessory Sec constituent SecDF has been proposed to contribute to protein export. Deletion of Staphylococcus aureus secDF has previously been shown to reduce resistance, to alter cell separation, and to change the expression of certain virulence factors. To analyse the impact of the secDF deletion in S. aureus on protein secretion, a quantitative secretome analysis was performed. Numerous Sec signal containing proteins involved in virulence were found to be decreased in the supernatant of the secDF mutant. However, two Sec-dependent hydrolases were increased in comparison to the wild type, suggesting additional indirect, regulatory effects to occur upon deletion of secDF. Adhesion, invasion, and cytotoxicity of the secDF mutant were reduced in human umbilical vein endothelial cells. Virulence was significantly reduced using a Galleria mellonella insect model. Altogether, SecDF is a promising therapeutic target for controlling S. aureus infections.
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Affiliation(s)
- Chantal Quiblier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bernd Roschitzki
- Functional Genomics Center Zurich, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Maria M. Senn
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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Paproski RJ, Yao SYM, Favis N, Evans D, Young JD, Cass CE, Zemp RJ. Human concentrative nucleoside transporter 3 transfection with ultrasound and microbubbles in nucleoside transport deficient HEK293 cells greatly increases gemcitabine uptake. PLoS One 2013; 8:e56423. [PMID: 23441192 PMCID: PMC3575408 DOI: 10.1371/journal.pone.0056423] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [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: 10/18/2012] [Accepted: 01/09/2013] [Indexed: 02/06/2023] Open
Abstract
Gemcitabine is a hydrophilic clinical anticancer drug that requires nucleoside transporters to cross plasma membranes and enter cells. Pancreatic adenocarcinomas with low levels of nucleoside transporters are generally resistant to gemcitabine and are currently a clinical problem. We tested whether transfection of human concentrative nucleoside transporter 3 (hCNT3) using ultrasound and lipid stabilized microbubbles could increase gemcitabine uptake and sensitivity in HEK293 cells made nucleoside transport deficient by pharmacologic treatment with dilazep. To our knowledge, no published data exists regarding the utility of using hCNT3 as a therapeutic gene to reverse gemcitabine resistance. Our ultrasound transfection system - capable of transfection of cell cultures, mouse muscle and xenograft CEM/araC tumors - increased hCNT3 mRNA and 3H-gemcitabine uptake by >2,000– and 3,400–fold, respectively, in dilazep-treated HEK293 cells. Interestingly, HEK293 cells with both functional human equilibrative nucleoside transporters and hCNT3 displayed 5% of 3H-gemcitabine uptake observed in cells with only functional hCNT3, suggesting that equilibrative nucleoside transporters caused significant efflux of 3H-gemcitabine. Efflux assays confirmed that dilazep could inhibit the majority of 3H-gemcitabine efflux from HEK293 cells, suggesting that hENTs were responsible for the majority of efflux from the tested cells. Oocyte uptake transport assays were also performed and provided support for our hypothesis. Gemcitabine uptake and efflux assays were also performed on pancreatic cancer AsPC-1 and MIA PaCa-2 cells with similar results to that of HEK293 cells. Using the MTS proliferation assay, dilazep-treated HEK293 cells demonstrated 13-fold greater resistance to gemcitabine compared to dilazep-untreated HEK293 cells and this resistance could be reversed by transfection of hCNT3 cDNA. We propose that transfection of hCNT3 cDNA using ultrasound and microbubbles may be a method to reverse gemcitabine resistance in pancreatic tumors that have little nucleoside transport activity which are resistant to almost all current anticancer therapies.
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Affiliation(s)
- Robert J. Paproski
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Sylvia Y. M. Yao
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Nicole Favis
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - David Evans
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - James D. Young
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Carol E. Cass
- Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Roger J. Zemp
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Horn S, Kersseboom S, Mayerl S, Müller J, Groba C, Trajkovic-Arsic M, Ackermann T, Visser TJ, Heuer H. Tetrac can replace thyroid hormone during brain development in mouse mutants deficient in the thyroid hormone transporter mct8. Endocrinology 2013; 154:968-79. [PMID: 23307789 DOI: 10.1210/en.2012-1628] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The monocarboxylate transporter 8 (MCT8) plays a critical role in mediating the uptake of thyroid hormones (THs) into the brain. In patients, inactivating mutations in the MCT8 gene are associated with a severe form of psychomotor retardation and abnormal serum TH levels. Here, we evaluate the therapeutic potential of the TH analog 3,5,3',5'-tetraiodothyroacetic acid (tetrac) as a replacement for T(4) in brain development. Using COS1 cells transfected with TH transporter and deiodinase constructs, we could show that tetrac, albeit not being transported by MCT8, can be metabolized to the TH receptor active compound 3,3',5-triiodothyroacetic acid (triac) by type 2 deiodinase and inactivated by type 3 deiodinase. Triac in turn is capable of replacing T(3) in primary murine cerebellar cultures where it potently stimulates Purkinje cell development. In vivo effects of tetrac were assessed in congenital hypothyroid Pax8-knockout (KO) and Mct8/Pax8 double-KO mice as well as in Mct8-KO and wild-type animals after daily injection of tetrac (400 ng/g body weight) during the first postnatal weeks. This treatment was sufficient to promote TH-dependent neuronal differentiation in the cerebellum, cerebral cortex, and striatum but was ineffective in suppressing hypothalamic TRH expression. In contrast, TSH transcript levels in the pituitary were strongly down-regulated in response to tetrac. Based on our findings we propose that tetrac administration offers the opportunity to provide neurons during the postnatal stage with a potent TH receptor agonist, thereby eventually reducing the neurological damage in patients with MCT8 mutations without deteriorating the thyrotoxic situation in peripheral tissues.
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Affiliation(s)
- Sigrun Horn
- Leibniz Institute for Age Research/Fritz Lipmann Institute, D-07745 Jena, Germany
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Ilori TO, Blount MA, Martin CF, Sands JM, Klein JD. Urine concentration in the diabetic mouse requires both urea and water transporters. Am J Physiol Renal Physiol 2013; 304:F103-11. [PMID: 23136000 PMCID: PMC3543621 DOI: 10.1152/ajprenal.00385.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [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: 07/10/2012] [Accepted: 10/31/2012] [Indexed: 11/22/2022] Open
Abstract
The regulation of the inner medullary collecting duct (IMCD) urea transporters (UT-A1, UT-A3) and aquaporin-2 (AQP2) and their interactions in diabetic animals is unknown. We investigated whether the urine concentrating defect in diabetic animals was a function of AQP2, the UT-As, or both transporters. UT-A1/UT-A3 knockout (UT-A1/A3 KO) mice produce dilute urine. We gave wild-type (WT) and UT-A1/A3 KO mice vasopressin via minipump for 7 days. In WT mice, vasopressin increased urine osmolality from 3,000 to 4,550 mosmol/kgH(2)O. In contrast, urine osmolality was low (800 mosmol/kgH(2)O) in the UT-A1/A3 KOs and remained low following vasopressin. Surprisingly, AQP2 protein abundance increased in UT-A1/A3 KO (114%) and WT (92%) mice. To define the role of UT-A1 and UT-A3 in the diabetic responses, WT and UT-A1/A3 KO mice were injected with streptozotocin (STZ). UT-A1/A3 KO mice showed only 40% survival at 7 days post-STZ injection compared with 70% in WT. AQP2 did not increase in the diabetic UT-A1/A3 KO mice compared with a 133% increase in WT diabetic mice. Biotinylation studies in rat IMCDs showed that membrane accumulation of UT-A1 increased by 68% in response to vasopressin in control rats but was unchanged by vasopressin in diabetic rat IMCDs. We conclude that, even with increased AQP2, UT-A1/UT-A3 is essential to optimal urine concentration. Furthermore, UT-A1 may be maximally membrane associated in diabetic rat inner medulla, making additional stimulation by vasopressin ineffective.
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43
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van de Kamp JM, Jakobs C, Gibson KM, Salomons GS. New insights into creatine transporter deficiency: the importance of recycling creatine in the brain. J Inherit Metab Dis 2013; 36:155-6. [PMID: 22968583 DOI: 10.1007/s10545-012-9537-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/26/2012] [Accepted: 08/14/2012] [Indexed: 11/24/2022]
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Malheiro R, Diogo L, Garcia P, Fineza I, Oliveira G. [Cerebral creatine deficiency syndromes]. ACTA MEDICA PORT 2012; 25:389-398. [PMID: 23534590] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 10/26/2012] [Indexed: 06/02/2023]
Abstract
INTRODUCTION Creatine deficiency syndromes are a recently described group of diseases characterized by inborn errors of creatine metabolism. Clinical features include a spectrum of neurodevelopment disorders of diverse severity. They are characterized by low levels of cerebral creatine caused by different pathogenic mutations concerning the genes coding for creatine synthesis enzymes [arginine: glicyne amidinotransferase (AGAT, EC 2.1.4.1) and guanidinoacetate methyltansferase (GAMT, EC 2.1.1.2)], AGAT and GAMT, respectively, or its transporter (CT1 deficiency), SLC6A8. Enzymatic deficiencies are transmitted as autosomal recessive traits, whereas the transporter deficit is X-linked. OBJECTIVES To characterize the clinical and laboratorial presentation, diagnosis and treatment of cerebral creatine deficiency patients, followed in Hospital Pediátrico Carmona da Mota. The awareness of these inborn errors of metabolism as neurological disorders, namely of neurodevelopment, among the medical community is a secondary aim of the present work. METHODS AND MATERIAL Retrospective analysis of the clinical files of patients followed in our Hospital and diagnosed with cerebral creatine deficiency syndrome. RESULTS Twelve patients belonging to seven different families were diagnosed with creatine deficiency syndromes. Five presented GAMT deficiency and seven CT1 deficiency. Present ages are 2 to 38 years old. The most common clinical presentations were: global development delay in seven patients (two with epilepsy), and speech delay in two patients. Only one patient had communication and social interaction dysfunction. In all, global development delay in the range of intellectual delay was identified. The pathognomonic pattern of cerebral creatine deficiency in the brain image was demonstrated in eight patients. Pathogenic mutations in GAMT or SLC6A8 genes were identified in all cases. CONCLUSIONS The suspicion of cerebral creatine depletion must be considered in all children presenting unexplained global psychomotor development delay. Pre-symptomatic therapy has shown promising results, especially in GAMT deficiency patients. The high rate of asymptomatic carriers of GAMT mutations in our population makes this disorder eligible to neonatal screening in Portugal.
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Affiliation(s)
- Rui Malheiro
- Faculdade de Medicina da Universidade de Coimbra, Coimbra, Portugal
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45
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Haack TB, Makowski C, Yao Y, Graf E, Hempel M, Wieland T, Tauer U, Ahting U, Mayr JA, Freisinger P, Yoshimatsu H, Inui K, Strom TM, Meitinger T, Yonezawa A, Prokisch H. Impaired riboflavin transport due to missense mutations in SLC52A2 causes Brown-Vialetto-Van Laere syndrome. J Inherit Metab Dis 2012; 35:943-8. [PMID: 22864630 PMCID: PMC3470687 DOI: 10.1007/s10545-012-9513-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 05/30/2012] [Accepted: 06/26/2012] [Indexed: 11/30/2022]
Abstract
Brown-Vialetto-Van Laere syndrome (BVVLS [MIM 211530]) is a rare neurological disorder characterized by infancy onset sensorineural deafness and ponto-bulbar palsy. Mutations in SLC52A3 (formerly C20orf54), coding for riboflavin transporter 2 (hRFT2), have been identified as the molecular genetic correlate in several individuals with BVVLS. Exome sequencing of just one single case revealed that compound heterozygosity for two pathogenic mutations in the SLC52A2 gene coding for riboflavin transporter 3 (hRFT3), another member of the riboflavin transporter family, is also associated with BVVLS. Overexpression studies confirmed that the gene products of both mutant alleles have reduced riboflavin transport activities. While mutations in SLC52A3 cause decreased plasma riboflavin levels, concordant with a role of SLC52A3 in riboflavin uptake from food, the SLC52A2-mutant individual had normal plasma riboflavin concentrations, a finding in line with a postulated function of SLC52A2 in riboflavin uptake from blood into target cells. Our results contribute to the understanding of human riboflavin metabolism and underscore its role in the pathogenesis of BVVLS, thereby providing a rational basis for a high-dose riboflavin treatment.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Biological Transport, Active/genetics
- Bulbar Palsy, Progressive/diagnosis
- Bulbar Palsy, Progressive/genetics
- Bulbar Palsy, Progressive/metabolism
- Child, Preschool
- DNA Mutational Analysis
- Female
- Hearing Loss, Sensorineural/diagnosis
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Humans
- Membrane Transport Proteins/deficiency
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Models, Biological
- Molecular Sequence Data
- Mutation, Missense
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Receptors, G-Protein-Coupled/deficiency
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Riboflavin/metabolism
- Sequence Homology, Amino Acid
- Syndrome
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Affiliation(s)
- Tobias B. Haack
- Institute of Human Genetics, Technische Universität München, Trogerstrasse 22, München, 81675 Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
| | - Christine Makowski
- Department of Pediatrics, Technische Universität München, Munich, 80804 Germany
| | - Yoshiaki Yao
- Department of Pharmacy, Kyoto University Hospital, Kyoto, 606-8507 Japan
| | - Elisabeth Graf
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
| | - Maja Hempel
- Institute of Human Genetics, Technische Universität München, Trogerstrasse 22, München, 81675 Germany
| | - Thomas Wieland
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
| | - Ulrike Tauer
- Department of Pediatrics, Technische Universität München, Munich, 80804 Germany
| | - Uwe Ahting
- Department of Clinical Chemistry, Städtisches Klinikum München, Munich, 80804 Germany
| | - Johannes A. Mayr
- Department of Paediatrics, Paracelsus Medical University Salzburg, Salzburg, 5020 Austria
| | - Peter Freisinger
- Department of Pediatrics, Klinikum Reutlingen, Reutlingen, 72764 Germany
| | - Hiroki Yoshimatsu
- Department of Pharmacy, Kyoto University Hospital, Kyoto, 606-8507 Japan
| | - Ken Inui
- Department of Pharmacy, Kyoto University Hospital, Kyoto, 606-8507 Japan
- Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, 607-8414 Japan
| | - Tim M. Strom
- Institute of Human Genetics, Technische Universität München, Trogerstrasse 22, München, 81675 Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Technische Universität München, Trogerstrasse 22, München, 81675 Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
| | - Atsushi Yonezawa
- Department of Pharmacy, Kyoto University Hospital, Kyoto, 606-8507 Japan
| | - Holger Prokisch
- Institute of Human Genetics, Technische Universität München, Trogerstrasse 22, München, 81675 Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, 85764 Germany
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46
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Fujita M, Hines CS, Zoghbi SS, Mallinger AG, Dickstein LP, Liow JS, Zhang Y, Pike VW, Drevets WC, Innis RB, Zarate CA. Downregulation of brain phosphodiesterase type IV measured with 11C-(R)-rolipram positron emission tomography in major depressive disorder. Biol Psychiatry 2012; 72:548-54. [PMID: 22677471 PMCID: PMC3438357 DOI: 10.1016/j.biopsych.2012.04.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [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: 02/24/2012] [Revised: 03/30/2012] [Accepted: 04/18/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Phosphodiesterase type IV (PDE4), an important component of the cyclic adenosine monophosphate (cAMP) cascade, selectively metabolizes cAMP in the brain to the inactive monophosphate. Basic studies suggest that PDE4 mediates the effects of several antidepressants. This study sought to quantify the binding of 11C-(R)-rolipram, a PDE4 inhibitor, as an indirect measure of this enzyme's activity in the brain of individuals with major depressive disorder (MDD) compared with healthy control subjects. METHODS 11C-(R)-Rolipram brain positron emission tomography scans were performed in 28 unmedicated MDD subjects and 25 age- and gender-matched healthy control subjects. Patients were moderately depressed and about one half were treatment-naive. 11C-(R)-Rolipram binding in the brain was measured using arterial 11C-(R)-rolipram levels to correct for the influence of cerebral blood flow. RESULTS Major depressive disorder subjects showed a widespread, approximately 20% reduction in 11C-(R)-rolipram binding (p = .002), which was not caused by different volumes of gray matter. Decreased rolipram binding of similar magnitudes was observed in most brain areas. Rolipram binding did not correlate with the severity of depressive or anxiety symptoms. CONCLUSIONS This study is the first to demonstrate that brain levels of PDE4, a critical enzyme that regulates cAMP, are decreased in unmedicated individuals with MDD in vivo. These results are in line with human postmortem and rodent studies demonstrating downregulation of the cAMP cascade in MDD and support the hypothesis that agents such as PDE4 inhibitors, which increase activity within the cAMP cascade, may have antidepressant effects.
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Affiliation(s)
- Masahiro Fujita
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1026, USA.
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47
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Kurosawa Y, DeGrauw TJ, Lindquist DM, Blanco VM, Pyne-Geithman GJ, Daikoku T, Chambers JB, Benoit SC, Clark JF. Cyclocreatine treatment improves cognition in mice with creatine transporter deficiency. J Clin Invest 2012; 122:2837-46. [PMID: 22751104 PMCID: PMC3408730 DOI: 10.1172/jci59373] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [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: 02/15/2012] [Accepted: 05/23/2012] [Indexed: 01/06/2023] Open
Abstract
The second-largest cause of X-linked mental retardation is a deficiency in creatine transporter (CRT; encoded by SLC6A8), which leads to speech and language disorders with severe cognitive impairment. This syndrome, caused by the absence of creatine in the brain, is currently untreatable because CRT is required for creatine entry into brain cells. Here, we developed a brain-specific Slc6a8 knockout mouse (Slc6a8-/y) as an animal model of human CRT deficiency in order to explore potential therapies for this syndrome. The phenotype of the Slc6a8-/y mouse was comparable to that of human patients. We successfully treated the Slc6a8-/y mice with the creatine analog cyclocreatine. Brain cyclocreatine and cyclocreatine phosphate were detected after 9 weeks of cyclocreatine treatment in Slc6a8-/y mice, in contrast to the same mice treated with creatine or placebo. Cyclocreatine-treated Slc6a8-/y mice also exhibited a profound improvement in cognitive abilities, as seen with novel object recognition as well as spatial learning and memory tests. Thus, cyclocreatine appears promising as a potential therapy for CRT deficiency.
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Affiliation(s)
- Yuko Kurosawa
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Ton J. DeGrauw
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Diana M. Lindquist
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Victor M. Blanco
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Gail J. Pyne-Geithman
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Takiko Daikoku
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - James B. Chambers
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Stephen C. Benoit
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
| | - Joseph F. Clark
- Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Neurology and
Department of Radiology and Imaging Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Emergency Medicine and
Department of Neurosurgery, University of Cincinnati, Cincinnati, Ohio, USA.
Division of Reproductive Science, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA.
Department of Psychiatry and Behavior Neuroscience, University of Cincinnati, Cincinnati, Ohio, USA
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Yao C, Anderson MO, Zhang J, Yang B, Phuan PW, Verkman AS. Triazolothienopyrimidine inhibitors of urea transporter UT-B reduce urine concentration. J Am Soc Nephrol 2012; 23:1210-20. [PMID: 22491419 PMCID: PMC3380644 DOI: 10.1681/asn.2011070751] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [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: 07/29/2011] [Accepted: 02/23/2012] [Indexed: 11/03/2022] Open
Abstract
Urea transport (UT) proteins facilitate the concentration of urine by the kidney, suggesting that inhibition of these proteins could have therapeutic use as a diuretic strategy. We screened 100,000 compounds for UT-B inhibition using an optical assay based on the hypotonic lysis of acetamide-loaded mouse erythrocytes. We identified a class of triazolothienopyrimidine UT-B inhibitors; the most potent compound, UTB(inh)-14, fully and reversibly inhibited urea transport with IC(50) values of 10 nM and 25 nM for human and mouse UT-B, respectively. UTB(inh)-14 competed with urea binding at an intracellular site on the UT-B protein. UTB(inh)-14 exhibited low toxicity and high selectivity for UT-B over UT-A isoforms. After intraperitoneal administration of UTB(inh)-14 in mice to achieve predicted therapeutic concentrations in the kidney, urine osmolality after administration of 1-deamino-8-D-arginine-vasopressin was approximately 700 mosm/kg H(2)O lower in UTB(inh)-14-treated mice than vehicle-treated mice. UTB(inh)-14 also increased urine output and reduced urine osmolality in mice given free access to water. UTB(inh)-14 did not reduce urine osmolality in UT-B knockout mice. In summary, these data provide proof of concept for the potential utility of UT inhibitors to reduce urinary concentration in high-vasopressin, fluid-retaining conditions. The diuretic mechanism of UT inhibitors may complement the action of conventional diuretics, which target sodium transport.
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Affiliation(s)
- Chenjuan Yao
- Department of Medicine, University of California, San Francisco, USA
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49
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Miller EF, Vaish S, Maier RJ. Efficiency of purine utilization by Helicobacter pylori: roles for adenosine deaminase and a NupC homolog. PLoS One 2012; 7:e38727. [PMID: 22701700 PMCID: PMC3368855 DOI: 10.1371/journal.pone.0038727] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Accepted: 05/14/2012] [Indexed: 01/06/2023] Open
Abstract
The ability to synthesize and salvage purines is crucial for colonization by a variety of human bacterial pathogens. Helicobacter pylori colonizes the gastric epithelium of humans, yet its specific purine requirements are poorly understood, and the transport mechanisms underlying purine uptake remain unknown. Using a fully defined synthetic growth medium, we determined that H. pylori 26695 possesses a complete salvage pathway that allows for growth on any biological purine nucleobase or nucleoside with the exception of xanthosine. Doubling times in this medium varied between 7 and 14 hours depending on the purine source, with hypoxanthine, inosine and adenosine representing the purines utilized most efficiently for growth. The ability to grow on adenine or adenosine was studied using enzyme assays, revealing deamination of adenosine but not adenine by H. pylori 26695 cell lysates. Using mutant analysis we show that a strain lacking the gene encoding a NupC homolog (HP1180) was growth-retarded in a defined medium supplemented with certain purines. This strain was attenuated for uptake of radiolabeled adenosine, guanosine, and inosine, showing a role for this transporter in uptake of purine nucleosides. Deletion of the GMP biosynthesis gene guaA had no discernible effect on mouse stomach colonization, in contrast to findings in numerous bacterial pathogens. In this study we define a more comprehensive model for purine acquisition and salvage in H. pylori that includes purine uptake by a NupC homolog and catabolism of adenosine via adenosine deaminase.
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Affiliation(s)
- Erica F. Miller
- Microbiology Department, The University of Georgia, Athens, Georgia, United States of America
| | - Soumya Vaish
- Microbiology Department, The University of Georgia, Athens, Georgia, United States of America
| | - Robert J. Maier
- Microbiology Department, The University of Georgia, Athens, Georgia, United States of America
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Subramanian VS, Subramanya SB, Said HM. Relative contribution of THTR-1 and THTR-2 in thiamin uptake by pancreatic acinar cells: studies utilizing Slc19a2 and Slc19a3 knockout mouse models. Am J Physiol Gastrointest Liver Physiol 2012; 302:G572-8. [PMID: 22194418 PMCID: PMC3311432 DOI: 10.1152/ajpgi.00484.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [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] [Indexed: 01/31/2023]
Abstract
Thiamin is essential for normal function of pancreatic acinar cells, and its deficiency leads to a reduction in pancreatic digestive enzymes. We have recently shown that thiamin uptake by rat pancreatic acinar cells is carrier-mediated and that both thiamin transporter (THTR)-1 and THTR-2 are expressed in these cells; little, however, is known about the relative contribution of these transporters toward total carrier-mediated thiamin uptake by these cells. We addressed this issue using a gene-specific silencing approach (siRNA) in mouse-derived pancreatic acinar 266-6 cells and Slc19a2 and Slc19a3 knockout mouse models. First we established that thiamin uptake by mouse pancreatic acinar cells is via a carrier-mediated process. We also established that these cells as well as native human pancreas express THTR-1 and THTR-2, with expression of the former (and activity of its promoter) being significantly higher than that of the latter. Using gene-specific siRNA against mouse THTR-1 and THTR-2, we observed a significant inhibition in carrier-mediated thiamin uptake by 266-6 cells in both cases. Similarly, thiamin uptake by freshly isolated primary pancreatic acinar cells of the Slc19a2 and Slc19a3 knockout mice was significantly lower than uptake by acinar cells of the respective littermates; the degree of inhibition observed in the former knockout model was greater than that of the latter. These findings demonstrate, for the first time, that both mTHTR-1 and mTHTR-2 are involved in carrier-mediated thiamin uptake by pancreatic acinar cells.
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