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Serrano J, Meshram NN, Soundarapandian MM, Smith KR, Mason C, Brown IS, Tyrberg B, Kyriazis GA. Saccharin Stimulates Insulin Secretion Dependent on Sweet Taste Receptor-Induced Activation of PLC Signaling Axis. Biomedicines 2022; 10:biomedicines10010120. [PMID: 35052799 PMCID: PMC8773316 DOI: 10.3390/biomedicines10010120] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/27/2021] [Accepted: 01/04/2022] [Indexed: 02/05/2023] Open
Abstract
Background: Saccharin is a common artificial sweetener and a bona fide ligand for sweet taste receptors (STR). STR can regulate insulin secretion in beta cells, so we investigated whether saccharin can stimulate insulin secretion dependent on STR and the activation of phospholipase C (PLC) signaling. Methods: We performed in vivo and in vitro approaches in mice and cells with loss-of-function of STR signaling and specifically assessed the involvement of a PLC signaling cascade using real-time biosensors and calcium imaging. Results: We found that the ingestion of a physiological amount of saccharin can potentiate insulin secretion dependent on STR. Similar to natural sweeteners, saccharin triggers the activation of the PLC signaling cascade, leading to calcium influx and the vesicular exocytosis of insulin. The effects of saccharin also partially require transient receptor potential cation channel M5 (TRPM5) activity. Conclusions: Saccharin ingestion may transiently potentiate insulin secretion through the activation of the canonical STR signaling pathway. These physiological effects provide a framework for understanding the potential health impact of saccharin use and the contribution of STR in peripheral tissues.
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Affiliation(s)
- Joan Serrano
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Nishita N. Meshram
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | | | - Kathleen R. Smith
- Sanford Burnham Prebys Medical Discovery Institute, Lake Nona, FL 32827, USA; (M.M.S.); (K.R.S.)
| | - Carter Mason
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Ian S. Brown
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Björn Tyrberg
- Department of Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden;
| | - George A. Kyriazis
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
- Correspondence: or
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Zhao Y, Goto M, Vaziri ND, Khazaeli M, Liu H, Farahanchi N, Khanifar E, Farzaneh T, Haslett PA, Moradi H, Soundarapandian MM. RNA Interference Targeting Liver Angiopoietin-Like Protein 3 Protects from Nephrotic Syndrome in a Rat Model Via Amelioration of Pathologic Hypertriglyceridemia. J Pharmacol Exp Ther 2020; 376:428-435. [PMID: 33443084 DOI: 10.1124/jpet.120.000257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/04/2020] [Indexed: 11/22/2022] Open
Abstract
Nephrotic syndrome (NS) is associated with metabolic perturbances including profound dyslipidemia characterized by hypercholesterolemia and hypertriglyceridemia. A major underlying mechanism of hypertriglyceridemia in NS is lipoprotein lipase (LPL) deficiency and dysfunction. There is emerging evidence that elevated angiopoietin-like protein 3 (ANGPTL3), an LPL inhibitor that is primarily expressed and secreted by hepatocytes, may be in part responsible for these findings. Furthermore, there is evidence pointing to the contribution of ANGPTL3 to the pathogenesis of proteinuria in NS. Therefore, we hypothesized that inhibition of hepatic ANGPTL3 by RNA interference will ameliorate dyslipidemia and other symptoms of NS and pave the way for a new therapeutic strategy. To this end, we used a subcutaneously delivered, GalNAc (N-Acetylgalactosamine)-conjugated small interfering RNA (siRNA) to selectively target and suppress liver Angptl3 in rats with puromycin-induced NS, which exhibits clinical features of NS including proteinuria, hypoalbuminemia, hyperlipidemia, and renal histologic abnormalities. The study demonstrated that siRNA-mediated knockdown of the liver Angptl3 relieved its inhibitory effect on LPL and significantly reduced hypertriglyceridemia in nephrotic rats. This was accompanied by diminished proteinuria and hypoalbuminemia, which are the hallmarks of NS, and significant attenuation of renal tissue inflammation and oxidative stress. Taken together, this study confirmed the hypothesis that suppression of Angptl3 is protective in NS and points to the possibility that the use of RNA interference to suppress hepatic Angptl3 can serve as a novel therapeutic strategy for NS. SIGNIFICANCE STATEMENT: The current standard of care for mitigating nephrotic dyslipidemia in nephrotic syndrome is statins therapy. However, the efficacy of statins and its safety in the context of impaired kidney function is not well established. Here, we present an alternate therapeutic approach by using siRNA targeting Angptl3 expressed in hepatocytes. As the liver is the major source of circulating Angptl3, siRNA treatment reduced the profound hypertriglyceridemia in a rat model of nephrotic syndrome and was also effective in improving kidney and cardiac function.
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Affiliation(s)
- Yitong Zhao
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Masaki Goto
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Nosratola D Vaziri
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Mahyar Khazaeli
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Han Liu
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Nazli Farahanchi
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Elham Khanifar
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Ted Farzaneh
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Patrick A Haslett
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Hamid Moradi
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
| | - Mangala M Soundarapandian
- Division of Nephrology and Hypertension, University of California, Irvine, California (Y.Z., M.G., N.D.V., M.K., H.L., N.F., H.M.); Long Beach Memorial Pathology Group, Long Beach, California (E.K.); Department of Pathology and Laboratory Medicine, University of California, Irvine, California (T.F.); Tibor Rubin VA Medical Center, Department of Medicine, Nephrology Section, Long Beach, California (H.M.); and Alnylam Pharmaceuticals Inc, Cambridge, Massachusetts (P.A.H., M.M.S.)
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Affiliation(s)
- Liya Wu
- Division of Translational Medicine and Human Genetics, Department of Medicine (L.W., J.S.M., D.J.R.), University of Pennsylvania, Philadelphia
| | | | | | - John S Millar
- Division of Translational Medicine and Human Genetics, Department of Medicine (L.W., J.S.M., D.J.R.), University of Pennsylvania, Philadelphia
| | - Daniel J Rader
- Division of Translational Medicine and Human Genetics, Department of Medicine (L.W., J.S.M., D.J.R.), University of Pennsylvania, Philadelphia.,Departments of Genetics, Medicine, and Pediatrics (D.J.R.), University of Pennsylvania, Philadelphia
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Soundarapandian MM, Juliana CA, Chai J, Haslett PA, Fitzgerald K, De León DD. Activation of Protein Kinase A (PKA) signaling mitigates congenital hyperinsulinism associated hypoglycemia in the Sur1-/- mouse model. PLoS One 2020; 15:e0236892. [PMID: 32735622 PMCID: PMC7394442 DOI: 10.1371/journal.pone.0236892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022] Open
Abstract
There is a significant unmet need for a safe and effective therapy for the treatment of children with congenital hyperinsulinism. We hypothesized that amplification of the glucagon signaling pathway could ameliorate hyperinsulinism associated hypoglycemia. In order to test this we evaluated the effects of loss of Prkar1a, a negative regulator of Protein Kinase A in the context of hyperinsulinemic conditions. With reduction of Prkar1a expression, we observed a significant upregulation of hepatic gluconeogenic genes. In wild type mice receiving a continuous infusion of insulin by mini-osmotic pump, we observed a 2-fold increase in the level of circulating ketones and a more than 40-fold increase in Kiss1 expression with reduction of Prkar1a. Loss of Prkar1a in the Sur1-/- mouse model of KATP hyperinsulinism significantly attenuated fasting induced hypoglycemia, decreased the insulin/glucose ratio, and also increased the hepatic expression of Kiss1 by more than 10-fold. Together these data demonstrate that amplification of the hepatic glucagon signaling pathway is able to rescue hypoglycemia caused by hyperinsulinism.
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Affiliation(s)
| | - Christine A. Juliana
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Jinghua Chai
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Patrick A. Haslett
- Alnylam Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Kevin Fitzgerald
- Alnylam Pharmaceuticals, Cambridge, Massachusetts, United States of America
| | - Diva D. De León
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (MMS); (DDDL)
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Sisino G, Zhou AX, Dahr N, Sabirsh A, Soundarapandian MM, Perera R, Larsson-Lekholm E, Magnone MC, Althage M, Tyrberg B. Long noncoding RNAs are dynamically regulated during β-cell mass expansion in mouse pregnancy and control β-cell proliferation in vitro. PLoS One 2017; 12:e0182371. [PMID: 28796801 PMCID: PMC5552087 DOI: 10.1371/journal.pone.0182371] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Pregnancy is associated with increased β-cell proliferation driven by prolactin. Long noncoding RNAs (lncRNA) are the most abundant RNA species in the mammalian genome, yet, their functional importance is mainly elusive. Aims/hypothesis: This study tests the hypothesis that lncRNAs regulate β-cell proliferation in response to prolactin in the context of β-cell mass compensation in pregnancy. Methods: The expression profile of lncRNAs in mouse islets at day 14.5 of pregnancy was explored by a bioinformatics approach, further confirmed by quantitative PCR at different days of pregnancy, and islet specificity was evaluated by comparing expression in islets versus other tissues. In order to establish the role of the candidate lncRNAs we studied cell proliferation in mouse islets and the MIN6 β-cell line by EdU incorporation and cell count. Results: We found that a group of lncRNAs is differentially regulated in mouse islets at 14.5 days of pregnancy. At different stages of pregnancy, these lncRNAs are dynamically expressed, and expression is prolactin dependent in mouse islets and MIN6 cells. One of those lncRNAs, Gm16308 (Lnc03), is dynamically regulated during pregnancy, prolactin-dependent and islet-enriched. Silencing Lnc03 in primary β-cells and MIN6 cells inhibits, whereas over-expression stimulates, proliferation even in the absence of prolactin, demonstrating that Lnc03 regulates β-cell growth. Conclusions/interpretation: During pregnancy mouse islet proliferation is correlated with dynamic changes of lncRNA expression. In particular, Lnc03 regulates mouse β-cell proliferation and may be a crucial component of β-cell proliferation in β-cell mass adaptation in both health and disease.
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Affiliation(s)
- Giorgia Sisino
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Alex-Xianghua Zhou
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Niklas Dahr
- Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Alan Sabirsh
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | | | - Ranjan Perera
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, United States of America
| | | | - Maria Chiara Magnone
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Magnus Althage
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
| | - Björn Tyrberg
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Mölndal, Sweden
- * E-mail:
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Ahn B, Soundarapandian MM, Sessions H, Peddibhotla S, Roth GP, Li JL, Sugarman E, Koo A, Malany S, Wang M, Yea K, Brooks J, Leone TC, Han X, Vega RB, Kelly DP. MondoA coordinately regulates skeletal myocyte lipid homeostasis and insulin signaling. J Clin Invest 2016; 126:3567-79. [PMID: 27500491 DOI: 10.1172/jci87382] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/09/2016] [Indexed: 01/09/2023] Open
Abstract
Intramuscular lipid accumulation is a common manifestation of chronic caloric excess and obesity that is strongly associated with insulin resistance. The mechanistic links between lipid accumulation in myocytes and insulin resistance are not completely understood. In this work, we used a high-throughput chemical biology screen to identify a small-molecule probe, SBI-477, that coordinately inhibited triacylglyceride (TAG) synthesis and enhanced basal glucose uptake in human skeletal myocytes. We then determined that SBI-477 stimulated insulin signaling by deactivating the transcription factor MondoA, leading to reduced expression of the insulin pathway suppressors thioredoxin-interacting protein (TXNIP) and arrestin domain-containing 4 (ARRDC4). Depleting MondoA in myocytes reproduced the effects of SBI-477 on glucose uptake and myocyte lipid accumulation. Furthermore, an analog of SBI-477 suppressed TXNIP expression, reduced muscle and liver TAG levels, enhanced insulin signaling, and improved glucose tolerance in mice fed a high-fat diet. These results identify a key role for MondoA-directed programs in the coordinated control of myocyte lipid balance and insulin signaling and suggest that this pathway may have potential as a therapeutic target for insulin resistance and lipotoxicity.
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Martin OJ, Lai L, Soundarapandian MM, Leone TC, Zorzano A, Keller MP, Attie AD, Muoio DM, Kelly DP. A role for peroxisome proliferator-activated receptor γ coactivator-1 in the control of mitochondrial dynamics during postnatal cardiac growth. Circ Res 2013; 114:626-36. [PMID: 24366168 DOI: 10.1161/circresaha.114.302562] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
RATIONALE Increasing evidence has shown that proper control of mitochondrial dynamics (fusion and fission) is required for high-capacity ATP production in the heart. Transcriptional coactivators, peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) α and PGC-1β, have been shown to regulate mitochondrial biogenesis in the heart at the time of birth. The function of PGC-1 coactivators in the heart after birth has been incompletely understood. OBJECTIVE Our aim was to assess the role of PGC-1 coactivators during postnatal cardiac development and in adult hearts in mice. METHODS AND RESULTS Conditional gene targeting was used in mice to explore the role of PGC-1 coactivators during postnatal cardiac development and in adult hearts. Marked mitochondrial structural derangements were observed in hearts of PGC-1α/β-deficient mice during postnatal growth, including fragmentation and elongation, associated with the development of a lethal cardiomyopathy. The expression of genes involved in mitochondrial fusion (Mfn1, Opa1) and fission (Drp1, Fis1) was altered in the hearts of PGC-1α/β-deficient mice. PGC-lα was shown to directly regulate Mfn1 gene transcription by coactivating the estrogen-related receptor α on a conserved DNA element. Surprisingly, PGC-1α/β deficiency in the adult heart did not result in evidence of abnormal mitochondrial dynamics or heart failure. However, transcriptional profiling demonstrated that PGC-1 coactivators are required for high-level expression of nuclear- and mitochondrial-encoded genes involved in mitochondrial dynamics and energy transduction in the adult heart. CONCLUSIONS These results reveal distinct developmental stage-specific programs involved in cardiac mitochondrial dynamics.
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Affiliation(s)
- Ola J Martin
- From the Diabetes and Obesity Research Center, Cardiovascular Pathobiology Program, Sanford-Burnham Medical Research Institute, Orlando, FL (O.J.M., L.L., M.M.S., T.C.L., D.P.K.); Institute for Research in Biomedicine, Barcelona, Spain (A.Z.); Department de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain (A.Z.); CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, Spain (A.Z.); Department of Biochemistry, University of Wisconsin-Madison, WI (M.P.K., A.D.A.); and Departments of Medicine, Pharmacology, and Cancer Biology, Duke University, Durham, NC (D.M.M.)
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Sugarman E, Koo A, Suyama E, Ruidiaz ME, Heynen-Genel S, Nguyen KH, Vasile S, Soundarapandian MM, Vega RB, Kelly DP, Smith LH, Malany S. Identification of Inhibitors of triacylglyceride accumulation in muscle cells: comparing HTS results from 1536-well plate-based and high-content platforms. ACTA ACUST UNITED AC 2013; 19:77-87. [PMID: 23989452 DOI: 10.1177/1087057113501198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Excess caloric consumption leads to triacylglyceride (TAG) accumulation in tissues that do not typically store fat, such as skeletal muscle. This ectopic accumulation alters cells, contributing to the pathogenesis of metabolic syndrome, a major health problem worldwide. We developed a 1536-well assay to measure intracellular TAG accumulation in differentiating H9c2 myoblasts. For this assay, cells were incubated with oleic acid to stimulate TAG accumulation prior to adding compounds. We used Nile red as a fluorescent dye to quantify TAG content with a microplate reader. The cell nuclei were counterstained with DAPI nuclear stain to assess cell count and filter cytotoxic compounds. In parallel, we developed an image-based assay in H9c2 cells to measure lipid accumulation levels via high-content analysis, exploiting the dual-emission spectra characteristic of Nile red staining of neutral and phospholipids. Using both approaches, we successfully screened ~227,000 compounds from the National Institutes of Health library. The screening data from the plate reader and IC50 values correlated with that from the Opera QEHS cell imager. The 1536-well plate reader assay is a powerful high-throughout screening platform to identify potent inhibitors of TAG accumulation to better understand the molecular pathways involved in lipid metabolism that lead to lipotoxicity.
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Affiliation(s)
- Eliot Sugarman
- 1Conrad Prebys Center for Chemical Genomics, Sanford Burham Medical Research Institute, Orlando, FL, USA
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Kyriazis GA, Mosure KR, Soundarapandian MM, Pratley RE, Tyrberg B. “Tasting” fructose with pancreatic beta-cells: modulation of insulin release by sweet taste receptor signaling and its role in metabolic diseases. BMC Proc 2012. [PMCID: PMC3374229 DOI: 10.1186/1753-6561-6-s3-p29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Soundarapandian MM, Selvaraj V, Lo UG, Golub MS, Feldman DH, Pleasure DE, Deng W. Zfp488 promotes oligodendrocyte differentiation of neural progenitor cells in adult mice after demyelination. Sci Rep 2011; 1:2. [PMID: 22355521 PMCID: PMC3210692 DOI: 10.1038/srep00002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 04/21/2011] [Accepted: 04/26/2011] [Indexed: 01/24/2023] Open
Abstract
Basic helix-loop-helix transcription factors Olig1 and Olig2 critically regulate oligodendrocyte development. Initially identified as a downstream effector of Olig1, an oligodendrocyte-specific zinc finger transcription repressor, Zfp488, cooperates with Olig2 function. Although Zfp488 is required for oligodendrocyte precursor formation and differentiation during embryonic development, its role in oligodendrogenesis of adult neural progenitor cells is not known. In this study, we tested whether Zfp488 could promote an oligodendrogenic fate in adult subventricular zone (SVZ) neural stem/progenitor cells (NSPCs). Using a cuprizone-induced demyelination model in mice, we examined the effect of retrovirus-mediated Zfp488 overexpression in SVZ NSPCs. Our results showed that Zfp488 efficiently promoted the differentiation of the SVZ NSPCs into mature oligodendrocytes in vivo. After cuprizone-induced demyelination injury, Zfp488-transduced mice also showed significant restoration of motor function to levels comparable to control mice. Together, these findings identify a previously unreported role for Zfp488 in adult oligodendrogenesis and functional remyelination after injury.
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Affiliation(s)
- Mangala M. Soundarapandian
- Departments of Cell Biology and Human Anatomy, University of California, Davis, Sacramento, California 95817, USA
| | - Vimal Selvaraj
- Department of Animal Science, Cornell University, Ithaca NY 14853, USA
| | - U-Ging Lo
- Departments of Cell Biology and Human Anatomy, University of California, Davis, Sacramento, California 95817, USA
| | - Mari S. Golub
- Murine Behavioral Assessment Laboratory, University of California, Davis, Sacramento, California 95817, USA
| | - Daniel H. Feldman
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California 95817, USA
| | - David E. Pleasure
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California 95817, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California 95817, USA
| | - Wenbin Deng
- Departments of Cell Biology and Human Anatomy, University of California, Davis, Sacramento, California 95817, USA
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California 95817, USA
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Selvaraj V, Soundarapandian MM, Chechneva O, Williams AJ, Sidorov MK, Soulika AM, Pleasure DE, Deng W. PARP-1 deficiency increases the severity of disease in a mouse model of multiple sclerosis. J Biol Chem 2009; 284:26070-84. [PMID: 19628872 DOI: 10.1074/jbc.m109.013474] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1) has been implicated in the pathogenesis of several central nervous system (CNS) disorders. However, the role of PARP-1 in autoimmune CNS injury remains poorly understood. Therefore, we studied experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis in mice with a targeted deletion of PARP-1. We identified inherent physiological abnormalities in the circulating and splenic immune composition between PARP-1(-/-) and wild type (WT) mice. Upon EAE induction, PARP-1(-/-) mice had an earlier onset and developed a more severe EAE compared with WT cohorts. Splenic response was significantly higher in PARP-1(-/-) mice largely because of B cell expansion. Although formation of Th1 and Th17 effector T lymphocytes was unaffected, PARP-1(-/-) mice had significantly earlier CD4+ T lymphocyte and macrophage infiltration into the CNS during EAE. However, we did not detect significant differences in cytokine profiles between PARP-1(-/-) and WT spinal cords at the peak of EAE. Expression analysis of different PARP isozymes in EAE spinal cords showed that PARP-1 was down-regulated in WT mice and that PARP-3 but not PARP-2 was dramatically up-regulated in both PARP-1(-/-) and WT mice, suggesting that these PARP isozymes could have distinct roles in different CNS pathologies. Together, our results indicate that PARP-1 plays an important role in regulating the physiological immune composition and in immune modulation during EAE; our finding identifies a new aspect of immune regulation by PARPs in autoimmune CNS pathology.
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Affiliation(s)
- Vimal Selvaraj
- Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, Sacramento, California 95817, USA
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Soundarapandian MM, Wu D, Zhong X, Petralia RS, Peng L, Tu W, Lu Y. Expression of functional Kir6.1 channels regulates glutamate release at CA3 synapses in generation of epileptic form of seizures. J Neurochem 2007; 103:1982-8. [PMID: 17883401 DOI: 10.1111/j.1471-4159.2007.04883.x] [Citation(s) in RCA: 38] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Kir6.1 channels are a subtype of ATP-sensitive inwardly rectifying potassium (K(ATP)) channels that play an essential role in coupling the cell's metabolic events to electrical activity. In this study, we show that functional Kir6.1 channels are located at excitatory pre-synaptic terminals as a complex with type-1 Sulfonylurea receptors (SUR1) in the hippocampus. The mutant mice with deficiencies in expressing the Kir6.1 or the SUR1 gene are more vulnerable to generation of epileptic form of seizures, compared to wild-type controls. Whole-cell patch clamp recordings demonstrate that genetic deletion of the Kir6.1/SUR1 channels enhances glutamate release at CA3 synapses. Hence, expression of functional Kir6.1/SUR1 channels inhibits seizure responses and possibly acts via limiting excitatory glutamate release.
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Affiliation(s)
- Mangala M Soundarapandian
- Biomedical Science Center, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, Florida, USA
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Peng PL, Zhong X, Tu W, Soundarapandian MM, Molner P, Zhu D, Lau L, Liu S, Liu F, Lu Y. ADAR2-dependent RNA editing of AMPA receptor subunit GluR2 determines vulnerability of neurons in forebrain ischemia. Neuron 2006; 49:719-33. [PMID: 16504947 DOI: 10.1016/j.neuron.2006.01.025] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [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: 10/07/2005] [Revised: 12/09/2005] [Accepted: 01/25/2006] [Indexed: 01/09/2023]
Abstract
ADAR2 is a nuclear enzyme essential for GluR2 pre-mRNA editing at Q/R site-607, which gates Ca2+ entry through AMPA receptor channels. Here, we show that forebrain ischemia in adult rats selectively reduces expression of ADAR2 enzyme and, hence, disrupts RNA Q/R site editing of GluR2 subunit in vulnerable neurons. Recovery of GluR2 Q/R site editing by expression of exogenous ADAR2b gene or a constitutively active CREB, VP16-CREB, which induces expression of endogenous ADAR2, protects vulnerable neurons in the rat hippocampus from forebrain ischemic insult. Generation of a stable ADAR2 gene silencing by delivering small interfering RNA (siRNA) inhibits GluR2 Q/R site editing, leading to degeneration of ischemia-insensitive neurons. Direct introduction of the Q/R site edited GluR2 gene, GluR2(R607), rescues ADAR2 degeneration. Thus, ADAR2-dependent GluR2 Q/R site editing determines vulnerability of neurons in the rat hippocampus to forebrain ischemia.
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Affiliation(s)
- Peter L Peng
- Biomolecular Science Center, College of Biomedical Sciences, University of Central Florida, Orlando, Florida 32816, USA
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Cilenti L, Kyriazis GA, Soundarapandian MM, Stratico V, Yerkes A, Park KM, Sheridan AM, Alnemri ES, Bonventre JV, Zervos AS. Omi/HtrA2 protease mediates cisplatin-induced cell death in renal cells. Am J Physiol Renal Physiol 2005; 288:F371-9. [PMID: 15454391 DOI: 10.1152/ajprenal.00154.2004] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [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] [Indexed: 11/22/2022] Open
Abstract
Omi/HtrA2 is a mitochondrial proapoptotic serine protease that is able to induce both caspase-dependent and caspase-independent cell death. After apoptotic stimuli, Omi is released to the cytoplasm where it binds and cleaves inhibitor of apoptosis proteins. In this report, we investigated the role of Omi in renal cell death following cisplatin treatment. Using primary mouse proximal tubule cells, as well as established renal cell lines, we show that the level of Omi protein is upregulated after treatment with cisplatin. This upregulation is followed by the release of Omi from mitochondria to the cytoplasm and degradation of XIAP. Reducing the endogenous level of Omi protein using RNA interference renders renal cells resistant to cisplatin-induced cell death. Furthermore, we show that the proteolytic activity of Omi is necessary and essential for cisplatin-induced cell death in this system. When renal cells are treated with Omi's specific inhibitor, ucf-101, they become significantly resistant to cisplatin-induced cell death. Ucf-101 was also able to minimize cisplatin-induced nephrotoxic injury in animals. Our results demonstrate that Omi is a major mediator of cisplatin-induced cell death in renal cells and suggest a way to limit renal injury by specifically inhibiting its proteolytic activity.
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Affiliation(s)
- Lucia Cilenti
- Biomolecular Science Center, Burnett College of Biomedical Science, University of Central Florida, 12722 Research Parkway, Orlando, FL 32826, USA
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Abstract
Ischemic stroke, or a brain attack, is the third leading cause of death in developed countries. A critical feature of the disease is a highly selective pattern of neuronal loss; certain identifiable subsets of neurons--particularly CA1 pyramidal neurons in the hippocampus are severely damaged, whereas others remain intact. A key step in this selective neuronal injury is Ca2+/Zn2+ entry into vulnerable neurons through alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor channels, a principle subtype of glutamate receptors. AMPA receptor channels are assembled from glutamate receptor (GluR)1, -2, -3, and -4 subunits. Circumstance data have indicated that the GluR2 subunits dictate Ca2+/Zn2+ permeability of AMPA receptor channels and gate injurious Ca2+/Zn2+ signals in vulnerable neurons. Therefore, targeting to the AMPA receptor subunit GluR2 can be considered a practical strategy for stroke therapy.
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Affiliation(s)
- Mangala M Soundarapandian
- Biomolecular Science Center, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, FL, USA
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Cilenti L, Soundarapandian MM, Kyriazis GA, Stratico V, Singh S, Gupta S, Bonventre JV, Alnemri ES, Zervos AS. Regulation of HAX-1 Anti-apoptotic Protein by Omi/HtrA2 Protease during Cell Death. J Biol Chem 2004; 279:50295-301. [PMID: 15371414 DOI: 10.1074/jbc.m406006200] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.3] [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] [Indexed: 11/06/2022] Open
Abstract
Omi/HtrA2 is a nuclear-encoded mitochondrial serine protease that has a pro-apoptotic function in mammalian cells. Upon induction of apoptosis, Omi translocates to the cytoplasm and participates in caspase-dependent apoptosis by binding and degrading inhibitor of apoptosis proteins. Omi can also initiate caspase-independent apoptosis in a process that relies entirely on its ability to function as an active protease. To investigate the mechanism of Omi-induced apoptosis, we set out to isolate novel substrates that are cleaved by this protease. We identified HS1-associated protein X-1 (HAX-1), a mitochondrial anti-apoptotic protein, as a specific Omi interactor that is cleaved by Omi both in vitro and in vivo. HAX-1 degradation follows Omi activation in cells treated with various apoptotic stimuli. Using a specific inhibitor of Omi, HAX-1 degradation is prevented and cell death is reduced. Cleavage of HAX-1 was not observed in a cell line derived from motor neuron degeneration 2 mice that carry a mutated form of Omi that affects its proteolytic activity. Degradation of HAX-1 is an early event in the apoptotic process and occurs while Omi is still confined in the mitochondria. Our results suggest that Omi has a unique pro-apoptotic function in mitochondria that involves removal of the HAX-1 anti-apoptotic protein. This function is distinct from its ability to activate caspase-dependent apoptosis in the cytoplasm by degrading inhibitor of apoptosis proteins.
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Affiliation(s)
- Lucia Cilenti
- Biomolecular Science Center, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, USA
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