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
|
Weaver JR, Odanga JJ, Breathwaite EK, Treadwell ML, Murchinson AC, Walters G, Fuentes DP, Lee JB. An increase in inflammation and islet dysfunction is a feature of prediabetes. Diabetes Metab Res Rev 2021; 37:e3405. [PMID: 33463010 DOI: 10.1002/dmrr.3405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/26/2020] [Accepted: 08/18/2020] [Indexed: 12/24/2022]
Abstract
AIMS Type 2 diabetes (T2D) is a global health problem that will be diagnosed in almost 300 million people by 2025 according to the World Health Organization. Before being diagnosed with T2D, individuals may have glucose levels above normal but below the diabetic range. This condition is known as prediabetes. Studies showed that people with prediabetes had an increase in several pro-inflammatory cytokines in their serum and in their fasting glucose levels. The answer remains unclear when inflammation begins in the pancreas and islets, and what is the extent of this inflammation. METHODS Subjects with haemoglobin A1c levels from 5.7% to 6.4% were classified as pre-diabetic. Sections of pancreas and isolated islets from normal donors and donors with prediabetes were tested for markers of inflammation and glucose-stimulated insulin secretion (GSIS). RESULTS Gene and protein expression of the inflammatory markers resistin, interleukin-1 beta, tumour necrosis factor-alpha, interleukin-6, and monocyte chemoattractant protein-1 increased in donors with prediabetes compared to normal donors. GSIS response was significantly decreased in pre-diabetic islets compared to normal islets. Donors with prediabetes also had decreased expression of CD163+ cells but not CD68+ cells. CONCLUSIONS Based on our findings, inflammation and islet dysfunction may be more significant than originally thought in people with prediabetes. Rather than being in a normal state before diabetes occurs, it appears that subjects are already in an early diabetic condition resembling more closely T2D.
Collapse
Affiliation(s)
- Jessica R Weaver
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Justin J Odanga
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Erick K Breathwaite
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Michelle L Treadwell
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Angela C Murchinson
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Gary Walters
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Danette P Fuentes
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| | - Jung Bok Lee
- Institute of Regenerative Medicine, LifeNet Health, Virginia Beach, Virginia, USA
| |
Collapse
|
3
|
Di Giacinto P, Rota F, Rizza L, Campana D, Isidori A, Lania A, Lenzi A, Zuppi P, Baldelli R. Chromogranin A: From Laboratory to Clinical Aspects of Patients with Neuroendocrine Tumors. Int J Endocrinol 2018; 2018:8126087. [PMID: 30057604 PMCID: PMC6051263 DOI: 10.1155/2018/8126087] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/12/2018] [Indexed: 12/13/2022] Open
Abstract
Background. Neuroendocrine tumors (NETs) are characterized by having behavior and prognosis that depend upon tumor histology, primary site, staging, and proliferative index. The symptoms associated with carcinoid syndrome and vasoactive intestinal peptide tumors are treated with octreotide acetate. The PROMID trial assesses the effect of octreotide LAR on the tumor growth in patients with well-differentiated metastatic midgut NETs. The CLARINET trial evaluates the effects of lanreotide in patients with nonfunctional, well-, or moderately differentiated metastatic enteropancreatic NETs. Everolimus has been approved for the treatment of advanced pancreatic NETs (pNETs) based on positive PFS effects, obtained in the treated group. Sunitinib is approved for the treatment of patients with progressive gastrointestinal stromal tumor or intolerance to imatinib, because a randomized study demonstrated that it improves PFS and overall survival in patients with advanced well-differentiated pNETs. In a phase II trial, pasireotide shows efficacy and tolerability in the treatment of patients with advanced NETs, whose symptoms of carcinoid syndrome were resistant to octreotide LAR. An open-label, phase II trial assesses the clinical activity of long-acting repeatable pasireotide in treatment-naive patients with metastatic grade 1 or 2 NETs. Even if the growth of the neoplasm was significantly inhibited, it is still unclear whether its antiproliferative action is greater than that of octreotide and lanreotide. Because new therapeutic options are needed to counter the natural behavior of neuroendocrine tumors, it would also be useful to have a biochemical marker that can be addressed better in the management of these patients. Chromogranin A is currently the most useful biomarker to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy.
Collapse
Affiliation(s)
- Paola Di Giacinto
- Endocrinological Oncology, Service of Endocrinology, A.O. San Camillo-Forlanini, Rome, Italy
| | - Francesca Rota
- Endocrinological Oncology, Service of Endocrinology, A.O. San Camillo-Forlanini, Rome, Italy
| | - Laura Rizza
- Endocrinological Oncology, Service of Endocrinology, A.O. San Camillo-Forlanini, Rome, Italy
| | - Davide Campana
- Department of Medical and Surgical Sciences, S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Andrea Isidori
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Andrea Lania
- Department of Endocrinology, Humanitas Clinical and Research Center, Humanitas University, Milan, Italy
| | - Andrea Lenzi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Paolo Zuppi
- Endocrinological Oncology, Service of Endocrinology, A.O. San Camillo-Forlanini, Rome, Italy
| | - Roberto Baldelli
- Endocrinological Oncology, Service of Endocrinology, A.O. San Camillo-Forlanini, Rome, Italy
| |
Collapse
|
4
|
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
|
5
|
Qiao XW, Qiu L, Chen YJ, Meng CT, Sun Z, Bai CM, Zhao DC, Zhang TP, Zhao YP, Song YL, Wang YH, Chen J, Lu CM. Chromogranin A is a reliable serum diagnostic biomarker for pancreatic neuroendocrine tumors but not for insulinomas. BMC Endocr Disord 2014; 14:64. [PMID: 25099181 PMCID: PMC4130880 DOI: 10.1186/1472-6823-14-64] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 07/30/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Pancreatic neuroendocrine tumors (PNETs) are a group of rare tumors. Chromogranin A (CgA) was considered as the most practical and useful serum tumor marker in PNET patients. But peripheral blood levels of CgA are not routinely tested in Chinese patients with PNETs. This study was to assess the diagnostic value of CgA in Chinese patients with PNETs especially in patients with insulinomas. METHODS Eighty-nine patients with PNETs including 57 insulinomas and 32 non-insulinoma PNETs as well as 86 healthy participants were enrolled in this study between September 2003 and June 2013. Serum levels of CgA were measured by ELISA method. Expression of CgA protein was detected in 26 PNET tissues including 14 insulinomas by immunohistochemical staining. RESULTS Serum levels of CgA in 89 PNET patients were significantly higher than that in healthy controls (P = 7.2 × 10-9). Serum levels of CgA in 57 patients with insulinomas (median 64.8 ng/ml, range 25-164) were slightly higher than the levels in healthy controls (median 53.4 ng/ml, range 39-94) but much lower than the levels in 32 patients with non-insulinoma PNETs (median 193 ng/ml, range 27-9021), P = 0.001. The serum CgA levels were reduced in 16 of 17 patients with insulinomas after tumor resection. ROC curve showed that CgA values at 60 ng/ml distinguished patients with insulinomas from healthy controls but its sensitivity and specificity were 66.7% and 73.3%, respectively. In contrast, CgA values at 74 ng/ml distinguished patients with non-insulinoma PNETs from healthy controls, and the sensitivity and specificity were 65.6% and 91.9%, respectively. Except for two insulinomas with negative staining of CgA, 12 insulinoma tissues showed positive staining of CgA. CONCLUSION CgA is a reliable serum diagnostic biomarker for PNETs but not for insulinomas.
Collapse
Affiliation(s)
- Xin-Wei Qiao
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| | - Ling Qiu
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| | - Yuan-Jia Chen
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
- Key Laboratory of Endocrinology (Ministry of Health), Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Chang-Ting Meng
- Department of Oncology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Zhao Sun
- Department of Oncology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Chun-Mei Bai
- Department of Oncology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Da-Chun Zhao
- Department of Pathology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Tai-Ping Zhang
- Department of Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Yu-Pei Zhao
- Key Laboratory of Endocrinology (Ministry of Health), Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
- Department of Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People’s Republic of China
| | - Yu-Li Song
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| | - Yu-Hong Wang
- Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510000, People’s Republic of China
| | - Jie Chen
- Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou 510000, People’s Republic of China
| | - Chong-Mei Lu
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, People’s Republic of China
| |
Collapse
|
6
|
Valicherla GR, Hossain Z, Mahata SK, Gayen JR. Pancreastatin is an endogenous peptide that regulates glucose homeostasis. Physiol Genomics 2013; 45:1060-71. [PMID: 24064537 DOI: 10.1152/physiolgenomics.00131.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pancreastatin (PST) is a regulatory peptide containing 49 amino acids, first isolated from porcine pancreas. Intracellular and extracellular processing of the prohormone Chromogranin A (Chga) results various bioactive peptides of which PST has dysglycemic activity. PST regulates glucose, lipid, and protein metabolism in liver and adipose tissues. It also regulates the secretion of leptin and expression of leptin and uncoupling protein 2 in adipose tissue. In Chga knockout mice, PST induces gluconeogenesis in the liver. PST reduces glucose uptake in mice hepatocytes and adipocytes. In rat hepatocytes, PST induces glycogenolysis and glycolysis and inhibits glycogen synthesis. In rat adipocytes, PST inhibits lactate production and lipogenesis. These metabolic effects are confirmed in humans. In the dual signaling mechanism of PST receptor, mostly PST activates Gαq/11 protein leads to the activation of phospholipase C β3-isoform, therefore increasing cytoplasmic free calcium and stimulating protein kinase C. PST inhibits the cell growth in rat HTC hepatoma cells, mediated by nitric oxide and cyclic GMP production. Elevated levels of PST correlating with catecholamines have been found in gestational diabetes and essential hypertension. Rise in the blood PST level in Type 2 diabetes suggests that PST is a negative regulator of insulin sensitivity and glucose homeostasis.
Collapse
Affiliation(s)
- Guru Raghavendra Valicherla
- Pharmacokinetics and Metabolism Division, Council of Scientific and Industrial Research-Central Drug Research Institute, Lucknow, India
| | | | | | | |
Collapse
|
7
|
Modlin IM, Gustafsson BI, Moss SF, Pavel M, Tsolakis AV, Kidd M. Chromogranin A--biological function and clinical utility in neuro endocrine tumor disease. Ann Surg Oncol 2010; 17:2427-43. [PMID: 20217257 DOI: 10.1245/s10434-010-1006-3] [Citation(s) in RCA: 244] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Indexed: 02/06/2023]
Abstract
BACKGROUND Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement. METHODS Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases. RESULTS CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation. CONCLUSIONS CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.
Collapse
Affiliation(s)
- Irvin M Modlin
- Gastrointestinal Pathobiology Research Group, Yale University School of Medicine, New Haven, CT, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Zhao E, Zhang D, Basak A, Trudeau VL. New insights into granin-derived peptides: evolution and endocrine roles. Gen Comp Endocrinol 2009; 164:161-74. [PMID: 19523383 DOI: 10.1016/j.ygcen.2009.01.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/31/2008] [Accepted: 01/20/2009] [Indexed: 11/22/2022]
Abstract
The granin protein family is composed of two chromogranin and five secretogranin members that are acidic, heat-stable proteins in secretory granules in cells of the nervous and endocrine systems. We report that there is little evidence for evolutionary relationships among the granins except for the chromogranin group. The main granin members, including chromogranin A and B, and secretogranin II are moderately conserved in the vertebrates. Several small bioactive peptides can be generated by proteolysis from those homologous domains existing within the granin precursors, reflecting the conservation of biological activities in different vertebrates. In this context, we focus on reviewing the distribution and function of the major granin-derived peptides, including vasostatin, bovine CgB(1-41) and secretoneurin in vertebrate endocrine systems, especially those associated with growth, glucose metabolism and reproduction.
Collapse
Affiliation(s)
- E Zhao
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada
| | | | | | | |
Collapse
|
9
|
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
|
10
|
Bargsten G. Cytological and immunocytochemical characterization of the insulin secreting insulinoma cell line RINm5F. ACTA ACUST UNITED AC 2004; 67:79-94. [PMID: 15125025 DOI: 10.1679/aohc.67.79] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The rat insulinoma cell line RINm5F, an insulin secreting pancreatic beta cell line, has been used as an attractive model for basic studies of the mechanisms of insulin secretion and, more recently, as a model for the development of alternative methods for the treatment of diabetes. To elucidate the cytological properties and expression patterns of hormones of the gastro-entero-pancreatic system, suspensions of RINm5F cells were investigated by various methods including immunocytochemistry on serial semithin sections, quantitative immunocytochemistry, routine electron microscopy, immuno-electron microscopy, in situ hybridization, and TUNEL technique. At the ultrastructural level, several phenotypes of RIm5F cells were characterized by differences in the number, shape, size, and density of their secretory granules. The most common type contained a mixture of round granules varying in size and electron density. A second type predominantly contained relatively large, moderately dense granules. Moreover, a minority of cells was characterized by the occurrence of polymorphous electron dense granules or the complete absence of any secretory granules. The immunohistochemical data showed that, among the established islet hormones, insulin was present in more than 50% of cells, whereas glucagon and somatostatin occurred only sporadically. Though cells positive for pancreatic polypeptide (PP) were not found, PP-related peptides (NPY and PYY) however could be detected in a minority of cells. The great majority of RINm5F cells were immunoreactive for chromogranin B (CgB), followed by insulin, chromogranin A (CgA), and serotonin (5-HT). In addition to intercellular differences in the density of immunostaining, numerous colocalizations of immunoreactivities were found, suggesting that RINm5F cells represent a mixture of subtypes concerning the individual pattern of hormone expression. The present results reveal a wide range of heterogeneity with respect to the morphology and especially the hormone content between individual RINm5F cells.
Collapse
Affiliation(s)
- Gerhard Bargsten
- Department of Microscopic Anatomy, Hannover Medical School, Hannover, Germany.
| |
Collapse
|
11
|
Kowluru A. Regulatory roles for small G proteins in the pancreatic beta-cell: lessons from models of impaired insulin secretion. Am J Physiol Endocrinol Metab 2003; 285:E669-84. [PMID: 12959934 DOI: 10.1152/ajpendo.00196.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Emerging evidence suggests that GTP-binding proteins (G proteins) play important regulatory roles in physiological insulin secretion from the islet beta-cell. Such conclusions were drawn primarily from experimental data derived through the use of specific inhibitors of G protein function. Data from gene depletion experiments appear to further substantiate key roles for these signaling proteins in the islet metabolism. The first part of this review will focus on findings supporting the hypothesis that activation of specific G proteins is essential for insulin secretion, including regulation of their function by posttranslational modifications at their COOH-terminal cysteines (e.g., isoprenylation). The second part will overview novel, non-receptor-dependent mechanism(s) whereby glucose might activate specific G proteins via protein histidine phosphorylation. The third section will review findings that appear to link abnormalities in the expression and/or functional activation of these key signaling proteins to impaired insulin secretion. It is hoped that this review will establish a basis for future research in this area of islet signal transduction, which presents a significant potential, not only in identifying key signaling proteins that are involved in physiological insulin secretion, but also in examining potential abnormalities in this signaling cascade that lead to islet dysfunction and onset of diabetes.
Collapse
Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences 3601, Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI 48202.
| |
Collapse
|
12
|
Amin RH, Chen HQ, Veluthakal R, Silver RB, Li J, Li G, Kowluru A. Mastoparan-induced insulin secretion from insulin-secreting betaTC3 and INS-1 cells: evidence for its regulation by Rho subfamily of G proteins. Endocrinology 2003; 144:4508-18. [PMID: 12960065 DOI: 10.1210/en.2003-0106] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mastoparan, a tetradecapeptide from wasp venom, stimulates insulin secretion from the islet beta-cells, presumably via activation of trimeric G proteins. Herein, we used Clostridial toxins, which selectively modify and inactivate the Rho subfamily of G proteins, to examine whether mastoparan-induced insulin secretion also involves activation of these signaling proteins. Mastoparan, but not mastoparan 17 (an inactive analog of mastoparan), significantly stimulated insulin secretion from betaTC3 and INS-1 cells. Preincubation of betaTC3 cells with either Clostridium difficille toxin B, which inactivates Rho, Cdc42, and Rac, or Clostridium sordellii toxin, which inactivates Ras, Rap, and Rac, markedly attenuated the mastoparan-induced insulin secretion, implicating Rac in this phenomenon. Mastoparan-stimulated insulin secretion was resistant to GGTI-2147, a specific inhibitor of geranylgeranylation of Rho G proteins (e.g. Rac), suggesting that mastoparan induces direct activation of Rac via GTP/GDP exchange. This was confirmed by a pull-down assay that quantifies the binding of activated (i.e. GTP-bound) Rac to p21-activated kinase. However, glucose-induced insulin secretion from these cells was abolished by toxin B or GGTI-2147, suggesting that the geranylgeranylation step is critical for glucose-stimulated secretion. Mastoparan significantly increased the translocation of cytosolic Rac and Cdc42 to the membrane fraction. Confocal light microscopy revealed a substantial degree of colocalization of Rac (and, to a lesser degree, Cdc42) with insulin in beta-cells exposed to mastoparan. Further, stable expression of a dominant negative (N17Rac) form of Rac into INS-1 cells resulted in a significant reduction in mastoparan-stimulated insulin secretion from these cells. Taken together, our findings implicate Rho G proteins, specifically Rac, in mastoparan-induced insulin release.
Collapse
Affiliation(s)
- Rajesh H Amin
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan 48201, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
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
|
14
|
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]
|