1
|
Garg R, Agarwal A, Katekar R, Dadge S, Yadav S, Gayen JR. Chromogranin A-derived peptides pancreastatin and catestatin: emerging therapeutic target for diabetes. Amino Acids 2023:10.1007/s00726-023-03252-x. [PMID: 36914766 DOI: 10.1007/s00726-023-03252-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/16/2023] [Indexed: 03/16/2023]
Abstract
Chromogranin A (ChgA) is an acidic pro-protein found in neuroendocrine organs, pheochromocytoma chromaffin granules, and tumor cells. Proteolytic processing of ChgA gives rise to an array of biologically active peptides such as pancreastatin (PST), vasostatin, WE14, catestatin (CST), and serpinin, which have diverse roles in regulating cardiovascular functions and metabolism, as well as inflammation. Intricate tissue-specific role of ChgA-derived peptide activity in preclinical rodent models of metabolic syndrome reveals complex effects on carbohydrate and lipid metabolism. Indeed, ChgA-derived peptides, PST and CST, play a pivotal role in metabolic syndrome such as obesity, insulin resistance, and diabetes mellitus. Additionally, supplementation of specific peptide in ChgA-KO mice have an opposing effect on physiological functions, such as PST supplementation reduces insulin sensitivity and enhances inflammatory response. In contrast, CST supplementation enhances insulin sensitivity and reduces inflammatory response. In this review, we focus on the tissue-specific role of PST and CST as therapeutic targets in regulating carbohydrate and lipid metabolism, along with the associated risk factors.
Collapse
Affiliation(s)
- Richa Garg
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Arun Agarwal
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Roshan Katekar
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shailesh Dadge
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shubhi Yadav
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India
| | - Jiaur R Gayen
- Pharmaceutics and Pharmacokinetics, CSIR-Central Drug Research Institute, Sector-10, Jankipuram Extension, Sitapur Road, Lucknow, 226031, India.
- Pharmacology Division, CSIR-Central Drug Research Institute, Jankipuram Extension, Lucknow, 226031, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| |
Collapse
|
2
|
Bulfoni M, Bouyioukos C, Zakaria A, Nigon F, Rapone R, Del Maestro L, Ait-Si-Ali S, Scharfmann R, Cosson B. Glucose controls co-translation of structurally related mRNAs via the mTOR and eIF2 pathways in human pancreatic beta cells. Front Endocrinol (Lausanne) 2022; 13:949097. [PMID: 35992129 PMCID: PMC9388909 DOI: 10.3389/fendo.2022.949097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Pancreatic beta cell response to glucose is critical for the maintenance of normoglycemia. A strong transcriptional response was classically described in rodent models but, interestingly, not in human cells. In this study, we exposed human pancreatic beta cells to an increased concentration of glucose and analysed at a global level the mRNAs steady state levels and their translationalability. Polysome profiling analysis showed an early acute increase in protein synthesis and a specific translation regulation of more than 400 mRNAs, independently of their transcriptional regulation. We clustered the co-regulated mRNAs according to their behaviour in translation in response to glucose and discovered common structural and sequence mRNA features. Among them mTOR- and eIF2-sensitive elements have a predominant role to increase mostly the translation of mRNAs encoding for proteins of the translational machinery. Furthermore, we show that mTOR and eIF2α pathways are independently regulated in response to glucose, participating to a translational reshaping to adapt beta cell metabolism. The early acute increase in the translation machinery components prepare the beta cell for further protein demand due to glucose-mediated metabolism changes.
Collapse
Affiliation(s)
- Manuel Bulfoni
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Costas Bouyioukos
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Albatoul Zakaria
- Université Paris Cité, Institut Cochin, INSERM, CNRS, Paris, France
| | - Fabienne Nigon
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | - Roberta Rapone
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
| | | | | | | | - Bertrand Cosson
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, Paris, France
- *Correspondence: Bertrand Cosson,
| |
Collapse
|
3
|
Herold Z, Doleschall M, Somogyi A. Role and function of granin proteins in diabetes mellitus. World J Diabetes 2021; 12:1081-1092. [PMID: 34326956 PMCID: PMC8311481 DOI: 10.4239/wjd.v12.i7.1081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/05/2021] [Accepted: 05/17/2021] [Indexed: 02/06/2023] Open
Abstract
The granin glycoprotein family consists of nine acidic proteins; chromogranin A (CgA), chromogranin B (CgB), and secretogranin II–VIII. They are produced by a wide range of neuronal, neuroendocrine, and endocrine cells throughout the human body. Their major intracellular function is to sort peptides and proteins into secretory granules, but their cleavage products also take part in the extracellular regulation of diverse biological processes. The contribution of granins to carbohydrate metabolism and diabetes mellitus is a recent research area. CgA is associated with glucose homeostasis and the progression of type 1 diabetes. WE-14, CgA10-19, and CgA43-52 are peptide derivates of CgA, and act as CD4+ or CD8+ autoantigens in type 1 diabetes, whereas pancreastatin (PST) and catestatin have regulatory effects in carbohydrate metabolism. Furthermore, PST is related to gestational and type 2 diabetes. CgB has a crucial role in physiological insulin secretion. Secretogranins II and III have angiogenic activity in diabetic retinopathy (DR), and are novel targets in recent DR studies. Ongoing studies are beginning to investigate the potential use of granin derivatives as drugs to treat diabetes based on the divergent relationships between granins and different types of diabetes.
Collapse
Affiliation(s)
- Zoltan Herold
- Division of Oncology, Department of Internal Medicine and Oncology, Semmelweis University, Budapest 1083, Hungary
- Department of Internal Medicine and Hematology, Semmelweis University, Budapest 1088, Hungary
| | - Marton Doleschall
- Molecular Medicine Research Group, Eotvos Lorand Research Network and Semmelweis University, Budapest 1089, Hungary
| | - Aniko Somogyi
- Department of Internal Medicine and Hematology, Semmelweis University, Budapest 1088, Hungary
| |
Collapse
|
4
|
Mahata SK, Corti A. Chromogranin A and its fragments in cardiovascular, immunometabolic, and cancer regulation. Ann N Y Acad Sci 2019; 1455:34-58. [PMID: 31588572 PMCID: PMC6899468 DOI: 10.1111/nyas.14249] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 09/09/2019] [Accepted: 09/13/2019] [Indexed: 12/11/2022]
Abstract
Chromogranin A (CgA)-the index member of the chromogranin/secretogranin secretory protein family-is ubiquitously distributed in endocrine, neuroendocrine, and immune cells. Elevated levels of CgA-related polypeptides, consisting of full-length molecules and fragments, are detected in the blood of patients suffering from neuroendocrine tumors, heart failure, renal failure, hypertension, rheumatoid arthritis, and inflammatory bowel disease. Full-length CgA and various CgA-derived peptides, including vasostatin-1, pancreastatin, catestatin, and serpinin, are expressed at different relative levels in normal and pathological conditions and exert diverse, and sometime opposite, biological functions. For example, CgA is overexpressed in genetic hypertension, whereas catestatin is diminished. In rodents, the administration of catestatin decreases hypertension, cardiac contractility, obesity, atherosclerosis, and inflammation, and it improves insulin sensitivity. By contrast, pancreastatin is elevated in diabetic patients, and the administration of this peptide to obese mice decreases insulin sensitivity and increases inflammation. CgA and the N-terminal fragment of vasostatin-1 can enhance the endothelial barrier function, exert antiangiogenic effects, and inhibit tumor growth in animal models, whereas CgA fragments lacking the CgA C-terminal region promote angiogenesis and tumor growth. Overall, the CgA system, consisting of full-length CgA and its fragments, is emerging as an important and complex player in cardiovascular, immunometabolic, and cancer regulation.
Collapse
Affiliation(s)
- Sushil K Mahata
- VA San Diego Healthcare System, San Diego, California.,Metabolic Physiology & Ultrastructural Biology Laboratory, Department of Medicine, University of California, San Diego, La Jolla, California
| | - Angelo Corti
- IRCCS San Raffaele Scientific Institute, San Raffaele Vita-Salute University, Milan, Italy
| |
Collapse
|
5
|
Inhibitory effects of vasostatin-1 against atherogenesis. Clin Sci (Lond) 2018; 132:2493-2507. [PMID: 30401690 DOI: 10.1042/cs20180451] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/11/2018] [Accepted: 11/05/2018] [Indexed: 12/22/2022]
Abstract
Vasostatin-1, a chromogranin A (CgA)-derived peptide (76 amino acids), is known to suppress vasoconstriction and angiogenesis. A recent study has shown that vasostatin-1 suppresses the adhesion of human U937 monocytes to human endothelial cells (HECs) via adhesion molecule down-regulation. The present study evaluated the expression of vasostatin-1 in human atherosclerotic lesions and its effects on inflammatory responses in HECs and human THP-1 monocyte-derived macrophages, macrophage foam cell formation, migration and proliferation of human aortic smooth muscle cells (HASMCs) and extracellular matrix (ECM) production by HASMCs, and atherogenesis in apolipoprotein E-deficient (ApoE-/-) mice. Vasostatin-1 was expressed around Monckeberg's medial calcific sclerosis in human radial arteries. Vasostatin-1 suppressed lipopolysaccharide (LPS)-induced up-regulation of monocyte chemotactic protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in HECs. Vasostatin-1 suppressed inflammatory M1 phenotype and LPS-induced interleukin-6 (IL-6) secretion via nuclear factor-κB (NF-κB) down-regulation in macrophages. Vasostatin-1 suppressed oxidized low-density lipoprotein (oxLDL)-induced foam cell formation associated with acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) and CD36 down-regulation and ATP-binding cassette transporter A1 (ABCA1) up-regulation in macrophages. In HASMCs, vasostatin-1 suppressed angiotensin II (AngII)-induced migration and collagen-3 and fibronectin expression via decreasing ERK1/2 and p38 phosphorylation, but increased elastin expression and matrix metalloproteinase (MMP)-2 and MMP-9 activities via increasing Akt and JNK phosphorylation. Vasostatin-1 did not affect the proliferation and apoptosis in HASMCs. Four-week infusion of vasostatin-1 suppressed the development of aortic atherosclerotic lesions with reductions in intra-plaque inflammation, macrophage infiltration, and SMC content, and plasma glucose level in ApoE-/- mice. These results indicate the inhibitory effects of vasostatin-1 against atherogenesis. The present study provided the first evidence that vasostatin-1 may serve as a novel therapeutic target for atherosclerosis.
Collapse
|
6
|
Wollam J, Mahata S, Riopel M, Hernandez-Carretero A, Biswas A, Bandyopadhyay GK, Chi NW, Eiden LE, Mahapatra NR, Corti A, Webster NJG, Mahata SK. Chromogranin A regulates vesicle storage and mitochondrial dynamics to influence insulin secretion. Cell Tissue Res 2017; 368:487-501. [PMID: 28220294 PMCID: PMC10843982 DOI: 10.1007/s00441-017-2580-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 01/16/2017] [Indexed: 01/01/2023]
Abstract
Chromogranin A (CgA) is a prohormone and a granulogenic factor that regulates secretory pathways in neuroendocrine tissues. In β-cells of the endocrine pancreas, CgA is a major cargo in insulin secretory vesicles. The impact of CgA deficiency on the formation and exocytosis of insulin vesicles is yet to be investigated. In addition, no literature exists on the impact of CgA on mitochondrial function in β-cells. Using three different antibodies, we demonstrate that CgA is processed to vasostatin- and catestatin-containing fragments in pancreatic islet cells. CgA deficiency in Chga-KO islets leads to compensatory overexpression of chromogranin B, secretogranin II, SNARE proteins and insulin genes, as well as increased insulin protein content. Ultrastructural studies of pancreatic islets revealed that Chga-KO β-cells contain fewer immature secretory granules than wild-type (WT) control but increased numbers of mature secretory granules and plasma membrane-docked vesicles. Compared to WT control, CgA-deficient β-cells exhibited increases in mitochondrial volume, numerical densities and fusion, as well as increased expression of nuclear encoded genes (Ndufa9, Ndufs8, Cyc1 and Atp5o). These changes in secretory vesicles and the mitochondria likely contribute to the increased glucose-stimulated insulin secretion observed in Chga-KO mice. We conclude that CgA is an important regulator for coordination of mitochondrial dynamics, secretory vesicular quanta and GSIS for optimal secretory functioning of β-cells, suggesting a strong, CgA-dependent positive link between mitochondrial fusion and GSIS.
Collapse
Affiliation(s)
- Joshua Wollam
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Sumana Mahata
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Matthew Riopel
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | - Angshuman Biswas
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | | | - Nai-Wen Chi
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
| | - Lee E Eiden
- Section on Molecular Neuroscience, NIMH-IRP, Bethesda, MD, USA
| | - Nitish R Mahapatra
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Angelo Corti
- IRCCS San Raffaele Scientific Institute, San Raffaele Vita-Salute University, Milan, Italy
| | - Nicholas J G Webster
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- VA San Diego Healthcare System, San Diego, CA, USA
| | - Sushil K Mahata
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
- VA San Diego Healthcare System, San Diego, CA, USA.
- Metabolic Physiology & Ultrastructural Biology Laboratory, Department of Medicine, University of California, San Diego (0732), 9500 Gilman Drive, La Jolla, CA, 92093-0732, USA.
| |
Collapse
|
7
|
Bandyopadhyay GK, Mahata SK. Chromogranin A Regulation of Obesity and Peripheral Insulin Sensitivity. Front Endocrinol (Lausanne) 2017; 8:20. [PMID: 28228748 PMCID: PMC5296320 DOI: 10.3389/fendo.2017.00020] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 01/23/2017] [Indexed: 01/15/2023] Open
Abstract
Chromogranin A (CgA) is a prohormone and granulogenic factor in endocrine and neuroendocrine tissues, as well as in neurons, and has a regulated secretory pathway. The intracellular functions of CgA include the initiation and regulation of dense-core granule biogenesis and sequestration of hormones in neuroendocrine cells. This protein is co-stored and co-released with secreted hormones. The extracellular functions of CgA include the generation of bioactive peptides, such as pancreastatin (PST), vasostatin, WE14, catestatin (CST), and serpinin. CgA knockout mice (Chga-KO) display: (i) hypertension with increased plasma catecholamines, (ii) obesity, (iii) improved hepatic insulin sensitivity, and (iv) muscle insulin resistance. These findings suggest that individual CgA-derived peptides may regulate different physiological functions. Indeed, additional studies have revealed that the pro-inflammatory PST influences insulin sensitivity and glucose tolerance, whereas CST alleviates adiposity and hypertension. This review will focus on the different metabolic roles of PST and CST peptides in insulin-sensitive and insulin-resistant models, and their potential use as therapeutic targets.
Collapse
Affiliation(s)
| | - Sushil K. Mahata
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Medicine, Metabolic Physiology and Ultrastructural Biology Laboratory, VA San Diego Healthcare System, San Diego, CA, USA
- *Correspondence: Sushil K. Mahata,
| |
Collapse
|
8
|
Abstract
Chromogranin A (CgA) is an established plasma marker of neuroendocrine tumors and has been suggested to also have a role as biomarker in other diseases. Whether CgA has any role as biomarker in diabetes is, however, unresolved, but its widespread distribution in the secretory granules in endocrine tissues including β cells and α cells in pancreas, and the metabolic effects of its peptide fragments suggest that CgA may play a pathophysiological role in diabetes, and thus also be a potential diabetes biomarker. In this review, we summarize the available information on CgA and some of its functional post-translational cleavage products in diabetes, followed by a discussion of its potential as a plasma marker in diabetes and the methodological concerns involved.
Collapse
Affiliation(s)
- Kasper Broedbaek
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark
| | - Linda Hilsted
- Department of Clinical Biochemistry, Copenhagen University Hospital, Rigshospitalet, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark
| |
Collapse
|
9
|
Abstract
Impaired insulin secretion from pancreatic β-cells is a major factor in the pathogenesis of type 2 diabetes. The main regulator of insulin secretion is the plasma glucose concentration. Insulin secretion is modified by other nutrients, circulating hormones and the autonomic nervous system, as well as local paracrine and autocrine signals. Autocrine signalling involves diffusible molecules that bind to receptors on the same cell from which they have been released. The first transmitter to be implicated in the autocrine regulation of β-cell function was insulin itself. The importance of autocrine insulin signalling is underscored by the finding that mice lacking insulin receptors in β-cells are glucose intolerant. In addition to insulin, β-cells secrete a variety of additional substances, including peptides (e.g. amylin, chromogranin A and B and their cleavage products), neurotransmitters (ATP and γ-aminobutyric acid) and ions (e.g. zinc). Here we review the autocrine effects of substances secreted from β-cells, with a focus on acute effects in stimulus-secretion coupling, present some novel data and discuss the general significance of autocrine signals for the regulation of insulin secretion.
Collapse
Affiliation(s)
- M Braun
- Alberta Diabetes Institute, University of Alberta, Edmonton, Canada.
| | | | | |
Collapse
|
10
|
Loh YP, Cheng Y, Mahata SK, Corti A, Tota B. Chromogranin A and derived peptides in health and disease. J Mol Neurosci 2012; 48:347-56. [PMID: 22388654 DOI: 10.1007/s12031-012-9728-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 02/14/2012] [Indexed: 01/29/2023]
Abstract
Chromogranin A (CgA) is a member of the granins, a family of acidic proteins found in abundance in (neuro)endocrine cells (e.g., in chromaffin cells) and in some tumors. Like other granins, CgA has a granulogenic role in secretory granule biogenesis and is stored in these organelles. CgA is partially processed differentially in various cell types to yield biologically active peptides, such as vasostatin, pancreastatin, catestatin, and serpinins. In this review, we describe the roles of CgA and several of its derived peptides. CgA, which is elevated in the blood of cancer patients, inhibits angiogenesis and exerts protective effects on the endothelial barrier function in tumors, thus affecting response to chemotherapy. Recent studies indicate that the serpinins promote cell survival and myocardial contractility and relaxation. Other peptides such as pancreastatin were found to have significant effects on inhibition of glucose-stimulated insulin secretion and glucose up-take, induction of glycogenolysis in hepatocytes, and inhibition of lipogenesis. In contrast, catestatin has opposite effects to that of pancreastatin in glucose metabolism and lipogenesis. Catestatin appears to also play a significant role in cardiac function, blood pressure regulation, and mutations in the catestatin domain of the CgA gene are associated with hypertension in humans.
Collapse
Affiliation(s)
- Y Peng Loh
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | | | | | | | | |
Collapse
|
11
|
Gayen JR, Saberi M, Schenk S, Biswas N, Vaingankar SM, Cheung WW, Najjar SM, O'Connor DT, Bandyopadhyay G, Mahata SK. A novel pathway of insulin sensitivity in chromogranin A null mice: a crucial role for pancreastatin in glucose homeostasis. J Biol Chem 2009; 284:28498-509. [PMID: 19706599 PMCID: PMC2781393 DOI: 10.1074/jbc.m109.020636] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/23/2009] [Indexed: 11/06/2022] Open
Abstract
Chromogranin A (CHGA/Chga), a proprotein, widely distributed in endocrine and neuroendocrine tissues (not expressed in muscle, liver, and adipose tissues), generates at least four bioactive peptides. One of those peptides, pancreastatin (PST), has been reported to interfere with insulin action. We generated a Chga knock-out (KO) mouse by the targeted deletion of the Chga gene in neuroendocrine tissues. KO mice displayed hypertension, higher plasma catecholamine, and adipokine levels and lower IL-6 and lipid levels compared with wild type mice. Liver glycogen content was elevated, but the nitric oxide (NO) level was diminished. Glucose, insulin, and pyruvate tolerance tests and hyperinsulinemic-euglycemic clamp studies established increased insulin sensitivity in liver but decreased glucose disposal in muscle. Despite higher catecholamine and ketone body levels and muscle insulin resistance, KO mice maintained euglycemia due to increased liver insulin sensitivity. Suppressed mRNA abundance of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase (G6Pase) in KO mice further support this conclusion. PST administration in KO mice stimulated phosphoenolpyruvate carboxykinase and G6Pase mRNA abundance and raised the blood glucose level. In liver cells transfected with G6Pase promoter, PST caused transcriptional activation in a protein kinase C (PKC)- and NO synthase-dependent manner. Thus, PST action may be mediated by suppressing IRS1/2-phosphatidylinositol 3-kinase-Akt-FOXO-1 signaling and insulin-induced maturation of SREBP1c by PKC and a high level of NO. The combined effects of conventional PKC and endothelial NO synthase activation by PST can suppress insulin signaling. The rise in blood PST level with age and in diabetes suggests that PST is a negative regulator of insulin sensitivity and glucose homeostasis.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Sonia M. Najjar
- the Center for Diabetes and Endocrine Research and Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio 43614-5804
| | - Daniel T. O'Connor
- From the Departments of Medicine
- Molecular Genetics, University of California, San Diego and
- Veterans Affairs San Diego Healthcare System, La Jolla, California 92093-0838 and
| | | | - Sushil K. Mahata
- From the Departments of Medicine
- Veterans Affairs San Diego Healthcare System, La Jolla, California 92093-0838 and
| |
Collapse
|
12
|
Sánchez-Margalet V, González-Yanes C, Santos-Alvarez J, Najib S. Pancreastatin. Biological effects and mechanisms of action. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2001; 482:247-62. [PMID: 11192586 DOI: 10.1007/0-306-46837-9_20] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- V Sánchez-Margalet
- Department of Medical Biochemistry and Molecular Biology, School of Medicine, and Investigation Unit, University Hospital Virgen Macarena, Seville, Spain
| | | | | | | |
Collapse
|
13
|
Potentiators and Inhibitors of Insulin Secretion. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1569-2558(08)60093-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|