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Ghanim AMH, Younis NS, Metwaly HA. Vanillin augments liver regeneration effectively in Thioacetamide induced liver fibrosis rat model. Life Sci 2021; 286:120036. [PMID: 34637793 DOI: 10.1016/j.lfs.2021.120036] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 07/05/2021] [Accepted: 10/04/2021] [Indexed: 12/12/2022]
Abstract
AIMS This study has been designed to investigate the role of vanillin either as prophylaxis or treatment in liver regeneration augmentation and liver fibrosis regression in thioacetamide (TAA) induced liver damage. MATERIALS AND METHODS Animals were injected with TAA to induce liver injury (200mg/kg twice weekly) for 8 weeks. In vanillin prophylaxis group; rats were administered vanillin (100 mg/Kg; IP, daily) from day 1 of TAA injection for 8 weeks. In vanillin treatment group; rats were confronted with the same dose of TAA injection for 8 weeks then treated with vanillin (100 mg/Kg, IP, daily) for 4 weeks. ALT, AST activities, serum albumin, hepatic GSH, MDA, HGF, VEGF, IL-6 and TNF-α levels were measured and also, MMP-2, TIMP-1 and cyclin D gene expression were determined. Liver sections were stained with H&E and Sirius red and immunostained for Ki-67 and α-SMA for histological and immunohistological changes analysis. KEY FINDINGS Vanillin improved liver function and histology. Also, showed a remarkable increase in hepatic HGF and VEGF level, and up-regulation of cyclin D1 expression accompanied by a significant up-regulation of MMP-2 and down- regulation of TIMP-1. All these effects were accompanied by TNF-α, IL-6 and oxidative stress significant attenuation. SIGNIFICANCE In conclusion, vanillin enhanced liver regeneration in TAA induced liver damage model; targeting growth factors (HGF, VEGF) and cellular proliferation marker cyclin D1. As well as stimulating fibrosis regression by inhibition of ECM accumulation and enhancing its degradation.
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Affiliation(s)
- Amal M H Ghanim
- Department of Biochemistry, Faculty of Pharmacy, Fayoum University, Fayoum 63514, Egypt.
| | - Nancy S Younis
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia; Department of Pharmacology, Zagazig University, Zagazig, Egypt.
| | - Heba A Metwaly
- Department of Biochemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt; Department of Pharmaceutical Biochemistry, Faculty of Pharmacy, Alexandria University, Alexandria 21500, Egypt.
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Rahimi Ghiasi M, Mohammadi H, Symonds ME, Tabei SMB, Salehi AR, Jafarpour S, Norouzi Barough L, Rahimi E, Amirkhani Z, Miraghajani M, Salehi R. Efficacy of insulin targeted gene therapy for type 1 diabetes mellitus: A systematic review and meta-analysis of rodent studies. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:406-415. [PMID: 32489555 PMCID: PMC7239425 DOI: 10.22038/ijbms.2020.39470.9359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 10/06/2019] [Indexed: 11/06/2022]
Abstract
Diabetes mellitus (DM) is a major worldwide public health challenge, for which gene therapy offers a potential therapeutic approach. To date, no systematic review or meta-analysis has been published in this area, so we examined all relevant published studies on rodents to elucidate the overall effects of gene therapy on bodyweight, intraperitoneal glucose tolerance test (IPGTT), fasting blood glucose, and insulin in animals with type 1 DM. The Cochrane Library, PubMed, Embase, ISI Web of Science, SCOPUS, and Google Scholar were systematically searched for potentially relevant studies. Mean±standard deviation (SD) was pooled using a random-effects model. After the primary search, out of 528 studies identified, 16 studies were in concordance with predefined criteria and selected for the final assessment. Of these, 12 studies used viral manipulation, and 4 employed non-viral vectors for gene delivery. The meta-analysis showed gene therapy with a viral vector decreased mean IPGTT (-12.69 mmol/l, P<0.001), fasting blood glucose (-13.51 mmol/l, P<0.001), insulin (398.28 pmol/l, P<0.001), and bodyweight (24.22 g, P<0.001), whereas non-viral vectors reduced fasting glucose (-29.95 mmol/l, P<0.001) and elevated insulin (114.92 pmol/l, P<0.001). Gene therapy has favorable effects on alleviating type 1 DM related factors in diabetic rodents.
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Affiliation(s)
- Moosa Rahimi Ghiasi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamed Mohammadi
- Food Security Research Center, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Michael E. Symonds
- The Early Life Research Unit, Division of Child Health, Obstetrics and Gynaecology, and Nottingham Digestive Disease Centre and Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Seyed Mohammad Bagher Tabei
- Department of Genetics & Maternal-Fetal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad Reza Salehi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Sima Jafarpour
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Leila Norouzi Barough
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Elnaz Rahimi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Zohreh Amirkhani
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Miraghajani
- The Early Life Research Unit, Division of Child Health, Obstetrics and Gynaecology, and Nottingham Digestive Disease Centre and Biomedical Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Salehi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
- Pediatric Inherited Diseases Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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Cardoso JCR, Félix RC, Costa C, Palma PFS, Canário AVM, Power DM. Evolution of the glucagon-like system across fish. Gen Comp Endocrinol 2018; 264:113-130. [PMID: 29056448 DOI: 10.1016/j.ygcen.2017.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/04/2017] [Accepted: 10/10/2017] [Indexed: 12/25/2022]
Abstract
In fishes, including the jawless lampreys, the most ancient lineage of extant vertebrates, plasma glucose levels are highly variable and regulation is more relaxed than in mammals. The regulation of glucose and lipid in fishes in common with mammals involves members of the glucagon (GCG)-like family of gastrointestinal peptides. In mammals, four peptides GCG, glucagon-like peptide 1 and 2 (GLP1 and GLP2) and glucose-dependent insulinotropic peptide (GIP) that activate four specific receptors exist. However, in lamprey and other fishes the glucagon-like family evolved differently and they retained additional gene family members (glucagon-related peptide, gcrp and its receptor, gcrpr) that are absent from mammals. In the present study, we analysed the evolution of the glucagon-like system in fish and characterized gene expression of the family members in the European sea bass (Dicentrarchus labrax) a teleost fish. Phylogenetic analysis revealed that multiple receptors and peptides of the glucagon-like family emerged early during the vertebrate radiation and evolved via lineage specific events. Synteny analysis suggested that family member gene loss is likely to be the result of a single gene deletion event. Lamprey was the only fish where a putative glp1r persisted and the presence of the receptor gene in the genomes of the elephant shark and coelacanth remains unresolved. In the coelacanth and elephant shark, unique proglucagon genes were acquired which in the former only encoded Gcg and Glp2 and in the latter, shared a similar structure to the teleost proglucagon gene but possessed an extra exon coding for Glp-like peptide that was most similar to Glp2. The variable tissue distribution of the gene transcripts encoding the ligands and receptors of the glucagon-like system in an advanced teleost, the European sea bass, suggested that, as occurs in mammals, they have acquired distinct functions. Statistically significant (p < .05) down-regulation of teleost proglucagon a in sea bass with modified plasma glucose levels confirmed the link between these peptides and metabolism. The tissue distribution of members of the glucagon-like system in sea bass and human suggests that evolution of the brain-gut-peptide regulatory loop diverged between teleosts and mammals despite the overall conservation and similarity of glucagon-like family members.
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Affiliation(s)
- João C R Cardoso
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Rute C Félix
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Carina Costa
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Pedro F S Palma
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Adelino V M Canário
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Deborah M Power
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
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Manell E, Hedenqvist P, Svensson A, Jensen-Waern M. Establishment of a Refined Oral Glucose Tolerance Test in Pigs, and Assessment of Insulin, Glucagon and Glucagon-Like Peptide-1 Responses. PLoS One 2016; 11:e0148896. [PMID: 26859145 PMCID: PMC4747562 DOI: 10.1371/journal.pone.0148896] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/25/2016] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus is increasing worldwide and reliable animal models are important for progression of the research field. The pig is a commonly used large animal model in diabetes research and the present study aimed to refine a model for oral glucose tolerance test (OGTT) in young growing pigs, as well as describing intravenous glucose tolerance test (IVGTT) in the same age group. The refined porcine OGTT will reflect that used in children and adolescents. Eighteen pigs were obtained one week after weaning and trained for two weeks to bottle-feed glucose solution, mimicking the human OGTT. The pigs subsequently underwent OGTT (1.75 g/kg BW) and IVGTT (0.5 g/kg BW). Blood samples were collected from indwelling vein catheters for measurements of glucose and the diabetes related hormones insulin, glucagon and active glucagon-like peptide-1. The study confirmed that pigs can be trained to bottle-feed glucose dissolved in water and thereby undergo an OGTT more similar to the human standard OGTT than previously described methods in pigs. With the refined method for OGTT, oral intake only consists of glucose and water, which is an advantage over previously described methods in pigs where glucose is given together with feed which will affect glucose absorption. Patterns of hormonal secretion in response to oral and intravenous glucose were similar to those in humans; however, the pigs were more glucose tolerant with lower insulin levels than humans. In translational medicine, this refined OGTT and IVGTT methods provide important tools in diabetes research when pigs are used as models for children and adolescents in diabetes research.
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Affiliation(s)
- Elin Manell
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
- * E-mail:
| | - Patricia Hedenqvist
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Svensson
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Marianne Jensen-Waern
- Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Nakayama K, Watanabe K, Boonvisut S, Makishima S, Miyashita H, Iwamoto S. Common variants of GIP are associated with visceral fat accumulation in Japanese adults. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1108-14. [PMID: 25324507 DOI: 10.1152/ajpgi.00282.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Animal studies have demonstrated that glucose-dependent insulinotropic polypeptide (GIP) and GIP receptor (GIPR) contribute to the etiology of obesity. In humans, genomewide association studies have identified single nucleotide polymorphisms (SNPs) in the GIPR gene that are strongly associated with body mass index (BMI); however, it is not clear whether genetic variations in the GIP gene are involved in the development of obesity. In the current study, we assessed the impact of GIP SNPs on obesity-related traits in Japanese adults. Six tag SNPs were tested for associations with obesity-related traits in 3,013 individuals. Multiple linear regression analyses showed that rs9904288, located at the 3'-end of GIP, was significantly associated with visceral fat area (VFA). Moreover, rs1390154 and rs4794008 showed significant associations with plasma triglyceride levels and hemoglobin A1c levels, respectively. Among the significant SNPs, rs9904288 and rs1390154 were independently linked with SNPs in active enhancers of the duodenum mucosa, the main GIP-secreting tissue. The haplotypes of these two SNPs exhibited stronger associations with VFA. Numbers of VFA-increasing alleles of rs9904288 and BMI-increasing alleles of previously identified GIPR SNPs showed a strong additive effect on VFA, waist circumference, and BMI in the subject population. These novel results support the notion that the GIP-GIPR axis plays a role in the etiology of central obesity in humans, which is characterized by the accumulation of visceral fat.
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Affiliation(s)
- Kazuhiro Nakayama
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; and
| | - Kazuhisa Watanabe
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; and
| | - Supichaya Boonvisut
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; and
| | - Saho Makishima
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; and
| | | | - Sadahiko Iwamoto
- Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; and
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Role of the glucose-dependent insulinotropic polypeptide and its receptor in the central nervous system: therapeutic potential in neurological diseases. Behav Pharmacol 2010; 21:394-408. [PMID: 20574409 DOI: 10.1097/fbp.0b013e32833c8544] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a 42-amino acid hormone, secreted from the enteroendocrine K cells, which has insulin-releasing and extra-pancreatic actions. GIP and its receptor present a widespread distribution in the mammalian brain where they have been implicated with synaptic plasticity, neurogenesis, neuroprotection and behavioral alterations. This review attempts to provide a comprehensive picture of the role of GIP in the central nervous system and to highlight recent findings from our group showing its potential involvement in neurological illnesses including epilepsies, Parkinson's disease and Alzheimer's disease.
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Hoo RLC, Chu JYS, Yuan Y, Yeung CM, Chan KYY, Chow BKC. Functional identification of an intronic promoter of the human glucose-dependent insulinotropic polypeptide gene. Gene 2010; 463:29-40. [PMID: 20452407 DOI: 10.1016/j.gene.2010.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 04/19/2010] [Accepted: 04/30/2010] [Indexed: 10/19/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP), a physiological incretin and enterogastrone, plays a vital role in regulating glucose-dependent insulin release from the pancreas and gastric acid secretion from the stomach. By using a transgenic mouse approach, we previously reported that the distal 1.2kb promoter region of the human GIP (hGIP) gene (-2545/-346, relative to the ATG) was able to target the transgene expression in the stomach but not in the small intestine where the majority of GIP-producing cells are located. In the present study, in order to identify the cis-acting element(s) that is/are required for intestinal expression, a 1.6kb (-1580/-) DNA fragment within the first intron of the hGIP gene was isolated and characterized in three GIP-expressing cell lines including HuTu80 (duodenal cells), PANC-1 (pancreatic ductal cells) and Hs746T (stomach cells). By 5' and 3' deletion analysis, a proximal promoter element was confined within the nucleotides -102/-1. This promoter element, functions in an orientation-dependent manner, was able to drive 15.1 and 18.3 fold increases in promoter activities in HuTu80 and PANC-1 cells, respectively. Site-directed mutation analysis indicated that the region -54/-23 was essential for promoter function while the region -22/-1 might possess opposite effects in HuTu80 and PANC-1 cells. In competitive and antibody supershift assays, interactions of the progesterone receptor (PR) and some unknown protein factors from HuTu80 and PANC-1 with the motif(s) at -54/-23 were evident. Consistent with this finding, we demonstrated the transcriptional regulation of the hGIP promoter by progesterone via the PR-B isoform and that progesterone treatment in both HuTu80 and PANC-1 cells resulted in an increase in hGIP transcript level. In addition, a sequence motif (ACATGT) residing -48/-43 was found to be responsible for the binding of potential TFII regulator(s). Taken together, our results suggest that the proximal intronic sequences contain essential cis-acting elements for the cell-specific expression of the hGIP gene.
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Affiliation(s)
- Ruby L C Hoo
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, PR China
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Fujita Y, Wideman RD, Asadi A, Yang GK, Baker R, Webber T, Zhang T, Wang R, Ao Z, Warnock GL, Kwok YN, Kieffer TJ. Glucose-dependent insulinotropic polypeptide is expressed in pancreatic islet alpha-cells and promotes insulin secretion. Gastroenterology 2010; 138:1966-75. [PMID: 20138041 DOI: 10.1053/j.gastro.2010.01.049] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 01/19/2010] [Accepted: 01/27/2010] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Glucose-dependent insulinotropic polypeptide (GIP) and the proglucagon product glucagon-like peptide-1 (GLP-1) are gastrointestinal hormones that are released in response to nutrient intake and promote insulin secretion. Interestingly, a subset of enteroendocrine cells express both GIP and GLP-1. We sought to determine whether GIP also might be co-expressed with proglucagon in pancreatic alpha-cells. METHODS We assessed GIP expression via reverse-transcription polymerase chain reaction, in situ hybridization, and immunohistochemistry. We developed a novel bioassay to measure GIP release from isolated islets, compared the biological activities of full-length and truncated GIP, and assessed the impact of immunoneutralization of islet GIP on glucose-stimulated insulin secretion in isolated islets. RESULTS GIP messenger RNA was present in mouse islets; GIP protein localized to islet alpha-cells of mouse, human, and snake pancreas, based on immunohistochemical analyses. However, using a C-terminal GIP antibody, immunoreactivity was detected in islets from prohormone convertase (PC) 2 knockout but not wild-type mice. Bioactive GIP was secreted from mouse and human islets after arginine stimulation. In the perfused mouse pancreas, GIP(1-42) and amidated GIP(1-30) had equipotent insulinotropic actions. Finally, immunoneutralization of GIP secreted by isolated islets decreased glucose-stimulated insulin secretion. CONCLUSIONS GIP is expressed in and secreted from pancreatic islets; in alpha-cells, PC2 processes proGIP to yield a truncated but bioactive form of GIP that differs from the PC1/3-derived form from K-cells. Islet-derived GIP promotes islet glucose competence and also could support islet development and/or survival.
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Affiliation(s)
- Yukihiro Fujita
- Laboratory of Molecular and Cellular Medicine, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Chapter 15 Glucose‐Dependent Insulinotropic Polypeptide (Gastric Inhibitory Polypeptide; GIP). VITAMINS AND HORMONES 2009; 80:409-71. [DOI: 10.1016/s0083-6729(08)00615-8] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Jepeal LI, Boylan MO, Wolfe MM. GATA-4 upregulates glucose-dependent insulinotropic polypeptide expression in cells of pancreatic and intestinal lineage. Mol Cell Endocrinol 2008; 287:20-9. [PMID: 18343025 PMCID: PMC2707930 DOI: 10.1016/j.mce.2008.01.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 01/17/2008] [Accepted: 01/22/2008] [Indexed: 11/18/2022]
Abstract
A thorough examination of glucose-dependent insulinotropic polypeptide (GIP) expression has been hampered by difficulty in isolating widely dispersed, GIP-producing enteroendocrine K-cells. To elucidate the molecular mechanisms governing the regulation of GIP expression, 14 intestinal and pancreatic cell lines were assessed for their suitability for studies examining GIP expression. Both STC-1 cells and the pancreatic cell line betaTC-3 were found to express GIP mRNA and secrete biologically active GIP. However, levels of GIP mRNA and bioactive peptide and the activity of transfected GIP reporter constructs were significantly lower in betaTC-3 than STC-1 cells. When betaTC-3 cells were analyzed for transcription factors known to be important for GIP expression, PDX-1 and ISL-1, but not GATA-4, were detected. Double staining for GIP-1 and GATA-4 in mouse duodenum demonstrated GATA-4 expression in intestinal K-cells. Exogenous expression of GATA-4 in betaTC-3 cells led to marked increases in both GIP transcription and secretion. Lastly suppression of GATA-4 via RNA interference, in GTC-1 cells, a subpopulation of STC-1 cells with high endogenous GIP expression resulted in a marked an attenuation of GIP promoter activity. Our data support the hypothesis that GATA-4 may function to augment or enhance GIP expression rather than act as an initiator of GIP transcription.
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Affiliation(s)
| | | | - M. Michael Wolfe
- Corresponding author at: Section of Gastroenterology, Boston Medical Center, 650 Albany Street, Boston, MA 02118, United States. Tel.: +1 617 638 8330; fax: +1 617 638 7785. E-mail address: (M. Michael Wolfe)
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Lan MS, Wang HW, Chong J, Breslin MB. Coupling of glucose response element from L-type pyruvate kinase and G6Pase promoter enhances glucose responsive activity in hepatoma cells. Mol Cell Biochem 2006; 300:191-6. [PMID: 17160355 DOI: 10.1007/s11010-006-9383-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Accepted: 11/07/2006] [Indexed: 11/24/2022]
Abstract
Type 1 diabetes results from the autoimmune destruction of pancreatic beta-cells, which leads to severe insulin deficiency. Insulin gene therapy provides an attractive approach to cure diabetes. The critical factor for insulin gene therapy in surrogate cells is to select an appropriate site for insulin expression and a tissue-specific promoter that is responsive to both physiological glucose and insulin concentrations. A novel chimeric promoter, (GIRE)n-G6Pase, consisting of a 1.6 kb glucose 6-phosphatase (G6Pase) promoter and a segment of the regulatory element derived from the L-type pyruvate kinase (L-PK) promoter, was designed to provide strong and tight control of insulin expression in liver. One or three copies of GIRE were linked to the G6Pase promoter, which showed a stronger promoter activity than the G6Pase promoter alone. The chimeric promoter was inhibited by insulin in a dosage-dependent manner and activated by glucose, two features essential for glucose metabolism. The promoter activity is conserved between species and highly specific for liver cells. The construction of a chimeric promoter with stronger and more sensitive responsive activity to glucose and insulin in liver cells could further advance studies in insulin gene therapy.
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Affiliation(s)
- Michael S Lan
- The Research Institute for Children, Departments of Pediatrics and Genetics, Children's Hospital, Louisiana State University Health Sciences Center, 200 Henry Clay Avenue, New Orleans, LA 70118, USA.
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Hansotia T, Drucker DJ. GIP and GLP-1 as incretin hormones: lessons from single and double incretin receptor knockout mice. ACTA ACUST UNITED AC 2005; 128:125-34. [PMID: 15780432 DOI: 10.1016/j.regpep.2004.07.019] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2004] [Revised: 07/08/2004] [Accepted: 07/15/2004] [Indexed: 11/18/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are gut-derived incretins secreted in response to nutrient ingestion. Both incretins potentiate glucose-dependent insulin secretion and enhance beta-cell mass through regulation of beta-cell proliferation, neogenesis and apoptosis. In contrast, GLP-1, but not GIP, inhibits gastric emptying, glucagon secretion, and food intake. Furthermore, human subjects with Type 2 diabetes exhibit relative resistance to the actions of GIP, but not GLP-1R agonists. The physiological importance of both incretins has been investigated through generation and analysis of incretin receptor knockout mice. Elimination of incretin receptor action in GIPR-/- or GLP-1R-/- mice produces only modest impairment in glucose homeostasis. Similarly, double incretin receptor knockout (DIRKO) mice exhibit normal body weight and normal levels of plasma glucagon and hypoglycemic responses to exogenous insulin. However, glucose-stimulated insulin secretion is significantly decreased following oral but not intraperitoneal glucose challenge in DIRKO mice and the glucose lowering actions of dipeptidyl peptidase-IV (DPP-IV) inhibitors are extinguished in DIRKO mice. Hence, incretin receptor signaling exerts physiologically relevant actions critical for glucose homeostasis, and represents a pharmacologically attractive target for development of agents for the treatment of Type 2 diabetes.
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Affiliation(s)
- Tanya Hansotia
- Department of Medicine, Banting and Best Diabetes Centre, Toronto General Hospital, and the University of Toronto, 200 Elizabeth Street MBRW4R-402, Toronto, Ontario, Canada M5G 2C4
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Jepeal LI, Boylan MO, Wolfe MM. Cell-specific expression of the glucose-dependent insulinotropic polypeptide gene functions through a GATA and an ISL-1 motif in a mouse neuroendocrine tumor cell line. REGULATORY PEPTIDES 2003; 113:139-47. [PMID: 12686473 DOI: 10.1016/s0167-0115(03)00046-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND/AIMS Glucose-dependent insulinotropic polypeptide (GIP) is a 42-amino acid gastrointestinal regulatory peptide that, in the presence of glucose, stimulates insulin secretion from beta-cells. GIP is expressed in gastrointestinal K-cells. Prior analysis of the GIP promoter demonstrated that 193 bases of the promoter are required to direct cell specific expression. Here we sought to identify and characterize the transcription factors involved. RESULTS By mutational analysis of the GIP promoter in a neuroendocrine cell line (STC-1), we identified two regions located between bases -193 and -182 and bases -156 and -151 that, when independently altered, were responsible for a 90% and 85% reduction in transcription, respectively. When we compared these two regions with known motifs from transcription factor databases, we identified the cis elements as potential GATA and ISL-1 binding sites. With subsequent electrophoretic mobility shift analysis (EMSA) using STC-1 nuclear extracts, we demonstrated the ability of these regions to form specific DNA protein complexes. Furthermore, we utilized antisera to confirm the specific binding of GATA-4 to the upstream site and ISL-1 to the downstream element. CONCLUSION These findings provide evidence for the involvement of the transcription factors GATA-4 and ISL-1 in the cell-specific expression of the GIP gene.
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Affiliation(s)
- Lisa I Jepeal
- Section of Gastroenterology, Boston University School of Medicine and Boston Medical Center, 650 Albany Street, Boston, MA 02118, USA
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Wang SY, Chi MMY, Li L, Moley KH, Wice BM. Studies with GIP/Ins cells indicate secretion by gut K cells is KATP channel independent. Am J Physiol Endocrinol Metab 2003; 284:E988-1000. [PMID: 12676650 DOI: 10.1152/ajpendo.00398.2002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
K cells are a subpopulation of enteroendocrine cells that secrete glucose-dependent insulinotropic polypeptide (GIP), a hormone that promotes glucose homeostasis and obesity. Therefore, it is important to understand how GIP secretion is regulated. GIP-producing (GIP/Ins) cell lines secreted hormones in response to many GIP secretagogues except glucose. In contrast, glyceraldehyde and methyl pyruvate stimulated hormone release. Measurements of intracellular glucose 6-phosphate, fructose 1,6-bisphosphate, and pyruvate levels, as well as glycolytic flux, in glucose-stimulated GIP/Ins cells indicated that glycolysis was not impaired. Analogous results were obtained using glucose-responsive MIN6 insulinoma cells. Citrate levels increased similarly in glucose-treated MIN6 and GIP/Ins cells. Thus pyruvate entered the tricarboxylic acid cycle. Glucose and methyl pyruvate stimulated 1.4- and 1.6-fold increases, respectively, in the ATP-to-ADP ratio in GIP/Ins cells. Glyceraldehyde profoundly reduced, rather than increased, ATP/ADP. Thus nutrient-regulated secretion is independent of the ATP-dependent potassium (K(ATP)) channel. Antibody staining of mouse intestine demonstrated that enteroendocrine cells producing GIP, glucagon-like peptide-1, CCK, or somatostatin do not express detectable levels of inwardly rectifying potassium (Kir) 6.1 or Kir 6.2, indicating that release of these hormones in vivo may also be K(ATP) channel independent. Conversely, nearly all cells expressing chromogranin A or substance P and approximately 50% of the cells expressing secretin or serotonin exhibited Kir 6.2 staining. Compounds that activate calcium mobilization were potent secretagogues for GIP/Ins cells. Secretion was only partially inhibited by verapamil, suggesting that calcium mobilization from intracellular and extracellular sources, independent from K(ATP) channels, regulates secretion from some, but not all, subpopulations of enteroendocrine cells.
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Affiliation(s)
- Song Yan Wang
- Division of Metabolism, Departments of Internal Medicine and Obstetrics and Gynecology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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15
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Ramshur EB, Rull TR, Wice BM. Novel insulin/GIP co-producing cell lines provide unexpected insights into Gut K-cell function in vivo. J Cell Physiol 2002; 192:339-50. [PMID: 12124779 DOI: 10.1002/jcp.10139] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Enteroendocrine (EE) cells represent complex, rare, and diffusely-distributed intestinal epithelial cells making them difficult to study in vivo. A specific sub-population of EE cells called Gut K-cells produces and secretes glucose-dependent insulinotropic peptide (GIP), a hormone important for glucose homeostasis. The factors that regulate hormone production and secretion, as well as the timing of peptide release, are remarkably similar for K-cells and islet beta-cells suggesting engineering insulin production by K-cells is a potential gene therapeutic strategy to treat diabetes. K-cell lines could be used to study the feasibility of this potential therapy and to understand Gut K-cell physiology in general. Heterogeneous STC-1 cells were transfected with a plasmid (pGIP/Neo) encoding neomycin phosphotransferase, driven by the GIP promoter-only cells in which the GIP promoter was active survived genetic selection. Additional clones expressing pGIP/Neo plus a GIP promoter/insulin transgene were isolated-only doubly transfected cells produced preproinsulin mRNA. Bioactive insulin was stored and then released following stimulation with arginine, peptones, and bombesin-physiological GIP secretagogues. Like K-cells in vivo, the GIP/insulin-producing cells express the critical glucose sensing enzyme, glucokinase. However, glucose did not regulate insulin or GIP secretion or mRNA levels. Conversely, glyceraldehyde and methyl-pyruvate were secretagogues, indicating cells depolarized in response to changes in intracellular metabolite levels. Potassium channel opening drugs and sulphonylureas had little effect on insulin secretion by K-cells. The K-cell lines also express relatively low levels of Kir 6.1, Kir 6.2, SUR1, and SUR2 suggesting secretion is independent of K(ATP) channels. These results provided unexpected insights into K-cell physiology and our experimental strategy could be easily modified to isolate/characterize additional EE cell populations.
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Affiliation(s)
- Erin B Ramshur
- Department of Internal Medicine, Division of Metabolism, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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16
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Abstract
Type 1 diabetes, along with its long-term complications, imposes a serious impact on public health. In spite of the development and application of various insulin formulations, exogenous insulin neither achieves the same degree of glycemic control as that provided by endogenous insulin, nor prevents the long-term complications associated with type 1 diabetes. As an alternative strategy, insulin gene transfer is being explored to restore endogenous insulin production in type 1 diabetes. Sustained hepatic insulin production has been shown to reverse ketonuria, prevent ketoacidosis, improve body weight gain and significantly ameliorate the adverse effects of insulin deficiency in diabetic animals. However, to achieve adequately regulated insulin production in response to changes in blood glucose concentrations remains a major hurdle. This article will review the most recent advances made to address this crucial limitation. In addition, based on the significance of maintaining basal plasma insulin for management of type 1 diabetes, we discuss the feasibility of developing basal hepatic insulin production as an auxiliary treatment to current insulin therapy for achieving tight glycemic control in type 1 diabetes.
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Affiliation(s)
- H Dong
- Institute for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, 1 Gustave L. Levy Place, PO Box 1496, New York, NY 10029, USA
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17
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Yeung CM, Chow BK. Identification of a proglucagon cDNA from Rana tigrina rugulosa that encodes two GLP-1s and that is alternatively spliced in a tissue-specific manner. Gen Comp Endocrinol 2001; 124:144-51. [PMID: 11703080 DOI: 10.1006/gcen.2001.7697] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucagon plays a pivotal role in the regulation of metabolism. A glucagon receptor has been previously characterized in the frog, Rana tigrina rugulosa, and the frog and human glucagon receptors have been shown to possess similar binding affinities toward human glucagon. To study the structural evolution of glucagon peptide and its receptor in vertebrates, in the current study, a proglucagon cDNA from the same frog species was cloned. Interestingly, in contrast to the mammalian proglucagons that contain only one GLP-1 peptide, the frog proglucagon cDNA encodes two GLP-1 peptides (GLP-1A and GLP-1B) in addition to a glucagon peptide and a glucagon-like peptide 2 (GLP-2). By reverse transcriptase-PCR (RT-PCR) analysis, the proglucagon gene expression was widely detected in the brain, colon, small intestine, liver, lung, and pancreas, suggesting that the proglucagon-derived peptides have diverse functions in frogs. Moreover, tissue-specific alternative mRNA splicing was observed in the brain, colon, and pancreas. In these tissues, proglucagon transcripts with a 135 bp in frame deletion encoding GLP-1A were found. This splicing event in R. tigrina rugulosa is novel because it deletes a GLP-1 encoding sequence instead of the GLP-2 observed in other vertebrates. These findings should enhance understanding of the proglucagon evolution, structure, and expression in vertebrates.
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Affiliation(s)
- C M Yeung
- Department of Zoology, University of Hong Kong, Pokfulam Road, Hong Kong
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Nakagawa A, Azuma S, Nakabayashi H. Novel gastroinsular axis involving a gastric transmural glucose flux and vagal mediation. Am J Physiol Endocrinol Metab 2001; 281:E304-14. [PMID: 11440907 DOI: 10.1152/ajpendo.2001.281.2.e304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine whether the appearance of nutrients into the gastric lumen per se provokes insulin secretion, glucose solution was instilled into the pylorus-cannulated stomach via an orogastric tube in anesthetized dogs. When 200 ml of 0, 5, 10, and 20% glucose solution were sequentially instilled, transgastric gradients (TGG) of plasma glucose concentration across the fundus [short gastric vein (SGV) - femoral artery, TGG(SGV)] and insulin levels in the superior pancreaticoduodenal vein (SPDV) increased stepwise. Upon instillation of 300 ml of 10% glucose, but not 1.8% saline, for 12 min followed by 48-min spontaneous drainage via the cannula (n = 5 each), TGG(SGV) and insulin levels in the SPDV increased concomitantly and significantly by 0.95 mM and 1,334 pM (mean), respectively, regardless of unaltered arterial glucose levels. The amount of secreted insulin (area under the curve) significantly correlated with the maximum TGG(SGV) (r = 0.693). In selectively gastric-vagotomized dogs (n = 5), insulin levels in the SPDV did not increase upon instillation despite a TGG(SGV) rise comparable to that in normal dogs. These results indicate that intragastric glucose appearance provokes vagus-mediated insulin secretion probably related to the transfundic glucose flux, suggesting the presence of a novel neurogenic gastroinsular axis.
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Affiliation(s)
- A Nakagawa
- Division of Endocrinology, Department of Internal Medicine, Kanazawa Medical University, Uchinada 920-0293, Japan
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Cheung AT, Dayanandan B, Lewis JT, Korbutt GS, Rajotte RV, Bryer-Ash M, Boylan MO, Wolfe MM, Kieffer TJ. Glucose-dependent insulin release from genetically engineered K cells. Science 2000; 290:1959-62. [PMID: 11110661 DOI: 10.1126/science.290.5498.1959] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Genetic engineering of non-beta cells to release insulin upon feeding could be a therapeutic modality for patients with diabetes. A tumor-derived K-cell line was induced to produce human insulin by providing the cells with the human insulin gene linked to the 5'-regulatory region of the gene encoding glucose-dependent insulinotropic polypeptide (GIP). Mice expressing this transgene produced human insulin specifically in gut K cells. This insulin protected the mice from developing diabetes and maintained glucose tolerance after destruction of the native insulin-producing beta cells.
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Affiliation(s)
- A T Cheung
- Department of Medicine, University of Alberta, Edmonton, AB T6G 2S2, Canada
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Abstract
This article summarizes data published during the past year that improve our understanding of the mechanisms by which various neurotransmitters, paracrine agents, and hormones regulate gastric acid secretion and are themselves regulated. The main stimulants of acid secretion are histamine, gastrin, and acetylcholine. The main inhibitor is somatostatin, which exerts a tonic restraint on parietal, enterochromaffin-like (ECL), and gastrin cells. Histamine, released from ECL cells, stimulates the parietal cell directly via H(2) receptors and indirectly via H(3) receptors coupled to inhibition of somatostatin secretion. Gastrin, acting via gastrin/cholecystokinin-B (CCK-B), now termed CCK(2), receptors on ECL cells activates histidine decarboxylase, releases histamine, and induces ECL hypertrophy and hyperplasia. The latter might be responsible for the rebound hyperacidity observed after withdrawal of long-term antisecretory therapy. The neurotransmitter pituitary adenylate cyclase-activating polypeptide stimulates histamine secretion from isolated ECL cells, but its physiologic role, if any, is not known. Acetylcholine, released from gastric postganglionic intramural neurons, stimulates the parietal cell directly via muscarinic M(3) receptors and indirectly by inhibiting somatostatin secretion. Although infection with H. pylori is associated with increased basal and stimulated acid outputs in patients with duodenal ulcer, most people infected with the organism are asymptomatic and have pangastritis with decreased acid output. In the latter, eradication of the bacterium leads to an increase in gastric acidity and is associated with a two-to threefold increase in gastroesophageal reflux.
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Affiliation(s)
- M L Schubert
- Department of Medicine, Division of Gastroenterology, Medical College of Virginia and McGuire VAMC, Richmond, Virginia 23249, USA.
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