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Mannino GC, Mancuso E, Sbrignadello S, Morettini M, Andreozzi F, Tura A. Chemical Compounds and Ambient Factors Affecting Pancreatic Alpha-Cells Mass and Function: What Evidence? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16489. [PMID: 36554367 PMCID: PMC9778390 DOI: 10.3390/ijerph192416489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
The exposure to different substances present in the environment can affect the ability of the human body to maintain glucose homeostasis. Some review studies summarized the current evidence about the relationships between environment and insulin resistance or beta-cell dysfunction. Instead, no reviews focused on the relationships between the environment and the alpha cell, although in recent years clear indications have emerged for the pivotal role of the alpha cell in glucose regulation. Thus, the aim of this review was to analyze the studies about the effects of chemical, biological, and physical environmental factors on the alpha cell. Notably, we found studies focusing on the effects of different categories of compounds, including air pollutants, compounds of known toxicity present in common objects, pharmacological agents, and compounds possibly present in food, plus studies on the effects of physical factors (mainly heat exposure). However, the overall number of relevant studies was limited, especially when compared to studies related to the environment and insulin sensitivity or beta-cell function. In our opinion, this was likely due to the underestimation of the alpha-cell role in glucose homeostasis, but since such a role has recently emerged with increasing strength, we expect several new studies about the environment and alpha-cell in the near future.
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Affiliation(s)
- Gaia Chiara Mannino
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Elettra Mancuso
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | | | - Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, 60131 Ancona, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Andrea Tura
- CNR Institute of Neuroscience, 35127 Padova, Italy
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Choi WT, Ghassemi Nejad J, Moon JO, Lee HG. Dietary supplementation of acetate-conjugated tryptophan alters feed intake, milk yield and composition, blood profile, physiological variables, and heat shock protein gene expression in heat-stressed dairy cows. J Therm Biol 2021; 98:102949. [PMID: 34016366 DOI: 10.1016/j.jtherbio.2021.102949] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/23/2021] [Accepted: 03/31/2021] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to investigate the effects of dietary supplementation of rumen-protected tryptophan (RPT) at four levels on milk yield, milk composition, blood profile, physiological variables, and heat shock protein gene expression in dairy cows under conditions of moderate-severe heat stress (MSHS, THI = 80~89). Sixteen early-lactating dairy cows (body weight = 719 ± 66.4 kg, days in milk = 74.3 ± 7.1, milk yield = 33.55 ± 3.74 kg, means ± SEM) were randomly assigned in a factorial arrangement to one of the four treatments: control group (n = 4, no RPT supplementation), 15 g/d RPT (n = 4), 30 g/d RPT (n = 4), or 60 g/d RPT group per cow (n = 4) supplemented to the TMR. A higher dry matter intake (DMI) and milk yield were found in the 30 g RPT group compared with the other groups, and the 3.5% fat-corrected milk yield, energy-corrected milk yield, milk fat, protein, β-casein, mono-unsaturated fatty acid, and poly-unsaturated fatty acid contents, and serum glucose content were observed in the 30 g RPT group (p < 0.05). The milk lactose concentration was significantly higher in the 30 g RPT group compared with the control and 60 g RPT groups (p < 0.05). The plasma cortisol level was lower, while the serotonin and melatonin concentrations were higher in the 30 g group compared with the other groups (p < 0.05). Heat shock protein (HSP) 70 expression was downregulated in the control and 15 g RPT groups, whereas the expression of HSP90 and HSPB1 remained unchanged among the groups. In particular, the 30 g RPT group was considered to have an improved DMI, milk yield, and lactose concentration, as well as anti-heat stress effects due to the simulation of serotonin and melatonin during MSHS.
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Affiliation(s)
- Won-Tae Choi
- Department of Animal Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Jalil Ghassemi Nejad
- Department of Animal Science and Technology, Konkuk University, Seoul, Republic of Korea
| | - Jun-Ok Moon
- Institute of Integrated Technology, CJ CheilJedang, Suwon, Republic of Korea
| | - Hong-Gu Lee
- Department of Animal Science and Technology, Konkuk University, Seoul, Republic of Korea.
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3
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Coloured Rice Phenolic Extracts Increase Expression of Genes Associated with Insulin Secretion in Rat Pancreatic Insulinoma β-cells. Int J Mol Sci 2020; 21:ijms21093314. [PMID: 32392844 PMCID: PMC7246603 DOI: 10.3390/ijms21093314] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/23/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022] Open
Abstract
Glucose-induced oxidative stress is associated with the overproduction of reactive oxygen species (ROS), which may dysregulate the expression of genes controlling insulin secretion leading to β-cell dysfunction, a hallmark of type 2 diabetes mellitus (T2DM). This study investigated the impact of coloured rice phenolic extracts (CRPEs) on the expression of key genes associated with β-cell function in pancreatic β-cells (INS-1E). These genes included glucose transporter 2 (Glut2), silent mating type information regulation 2 homolog 1 (Sirt1), mitochondrial transcription factor A (Tfam), pancreatic/duodenal homeobox protein 1 (Pdx-1) and insulin 1 (Ins1). INS-1E cells were cultured in high glucose (25 mM) to induce glucotoxic stress conditions (HGSC) and in normal glucose conditions (NGC-11.1 mM) to represent normal β-cell function. Cells were treated with CRPEs derived from two coloured rice cultivars, Purple and Yunlu29-red varieties at concentrations ranged from 50 to 250 µg/mL. CRPEs upregulated the expression of Glut2, Sirt1 and Pdx-1 significantly at 250 µg/mL under HGSC. CRPEs from both cultivars also upregulated Glut2, Sirt1, Tfam, Pdx-1 and Ins1 markedly at 250 µg/mL under NGC with Yunlu29 having the greatest effect. These data suggest that CRPEs may reduce β-cell dysfunction in T2DM by upregulating the expression of genes involved in insulin secretion pathways.
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Min L, Zhao S, Tian H, Zhou X, Zhang Y, Li S, Yang H, Zheng N, Wang J. Metabolic responses and "omics" technologies for elucidating the effects of heat stress in dairy cows. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2017; 61:1149-1158. [PMID: 27904969 PMCID: PMC5486771 DOI: 10.1007/s00484-016-1283-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
Heat stress (HS) negatively affects various industries that rely on animal husbandry, particularly the dairy industry. A better understanding of metabolic responses in HS dairy cows is necessary to elucidate the physiological mechanisms of HS and offer a new perspective for future research. In this paper, we review the current knowledge of responses of body metabolism (lipid, carbohydrate, and protein), endocrine profiles, and bovine mammary epithelial cells during HS. Furthermore, we summarize the metabolomics and proteomics data that have revealed the metabolite profiles and differentially expressed proteins that are a feature of HS in dairy cows. Analysis of metabolic changes and "omics" data demonstrated that HS is characterized by reduced lipolysis, increased glycolysis, and catabolism of amino acids in dairy cows. Here, analysis of the impairment of immune function during HS and of the inflammation that arises after long-term HS might suggest new strategies to ameliorate the effects of HS in dairy production.
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Affiliation(s)
- Li Min
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Shengguo Zhao
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - He Tian
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - Xu Zhou
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - Yangdong Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - Songli Li
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - Hongjian Yang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Nan Zheng
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China
| | - Jiaqi Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, People's Republic of China.
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5
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Al-Dawood A. Effect of heat stress on adipokines and some blood metabolites in goats from Jordan. Anim Sci J 2016; 88:356-363. [DOI: 10.1111/asj.12636] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 01/20/2016] [Accepted: 02/10/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Amani Al-Dawood
- National Center for Agricultural Research and Extension (NCARE); Baq'a Jordan
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Liu J, Gao F, Ji B, Wang R, Yang J, Liu H, Zhou F. Anthocyanins-rich extract of wild Chinese blueberry protects glucolipotoxicity-induced INS832/13 β-cell against dysfunction and death. Journal of Food Science and Technology 2014; 52:3022-9. [PMID: 25892804 DOI: 10.1007/s13197-014-1379-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 04/09/2014] [Accepted: 04/15/2014] [Indexed: 01/08/2023]
Abstract
As commonly observed events in diabetic patients, glucolipotoxicity induces oxidative stress, apoptosis and functional defects in β-cells. Anthocyanins are well investigated as strong antioxidants and modulators for metabolic syndromes. Therefore, this study examined the protective effects of anthocyanins-rich extracts (BAE) from wild Chinese blueberry (Vaccinium spp.) against glucolipotoxicity in β-cells. Results showed that INS832/13 β-cells subjected to glucolipotoxicity were significantly decreased (p < 0.05) in cell survival rate, which were alleviated by BAE and metformin treatments. Both BAE and metformin reduced reactive oxidative species and improved the antioxidant defense system. Moreover, BAE were effective in reducing intracellular triglycerides (TG) level, restoring intracellular insulin content, lowering basal insulin secretion (BIS) and increasing glucose-stimulated insulin secretion which in turn resulted in an elevated insulin secretion index. However, metformin only demonstrated marginal effect on secretion dysfunction and had no effect (p > 0.05) on BIS or TG. Additionally, TG levels reduced by BAE treatment were correlated with BIS (p < 0.01, r = 0.9755). This study has for the first time demonstrated that anthocyanin enriched extract of wild Chinese blueberry could effectively protect β-cells against glucolipotoxicity in vitro. These results implied the potential efficacy of BAE as a complementary measure for diabetes intervention.
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Affiliation(s)
- Jia Liu
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Fengyi Gao
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Baoping Ji
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China ; China Agricultural University, Mailbox #294, #17 Qinghua East Road, Haidian District, Beijing, 100083 People's Republic of China
| | - Ruojun Wang
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Junsi Yang
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Huijun Liu
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Feng Zhou
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
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7
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WANG R, LIU J, GUO X, GAO F, JI B, ZHOU F. Vitamin C Protects against INS832/13 ^|^beta;-Cell Death and/or Dysfunction Caused by Glucolipotoxicity or 3T3-L1 Adipocyte Coculture. J Nutr Sci Vitaminol (Tokyo) 2014. [DOI: 10.3177/jnsv.60.313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ruojun WANG
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University
| | - Jia LIU
- China National Research Institute of Food and Fermentation Industries
| | - Xiaoxuan GUO
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University
| | - Fengyi GAO
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University
| | - Baoping JI
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University
| | - Feng ZHOU
- Beijing Key Laboratory of Functional Food from Plant Resources, College of Food Science and Nutritional Engineering, China Agricultural University
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Baumgard LH, Rhoads RP. Ruminant Nutrition Symposium: ruminant production and metabolic responses to heat stress. J Anim Sci 2011; 90:1855-65. [PMID: 22205665 DOI: 10.2527/jas.2011-4675] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Heat stress compromises efficient animal production by marginalizing nutrition, management, and genetic selection efforts to maximize performance endpoints. Modifying farm infrastructure has yielded modest success in mitigating heat stress-related losses, yet poor production during the summer remains arguably the costliest issue facing livestock producers. Reduced output (e.g., milk yield and muscle growth) during heat stress was traditionally thought to result from decreased nutrient intake (i.e., a classic biological response shared by all animals during environmental-induced hyperthermia). Our recent observations have begun to challenge this belief and indicate heat-stressed animals employ novel homeorhetic strategies to direct metabolic and fuel selection priorities independently of nutrient intake or energy balance. Alterations in systemic physiology support a shift in carbohydrate metabolism, evident by increased basal and stimulated circulating insulin concentrations. Perhaps most intriguing given the energetic shortfall of the heat-stressed animal is the apparent lack of basal adipose tissue mobilization coupled with a reduced responsiveness to lipolytic stimuli. Thus, the heat stress response markedly alters postabsorptive carbohydrate, lipid, and protein metabolism independently of reduced feed intake through coordinated changes in fuel supply and utilization by multiple tissues. Interestingly, the systemic, cellular, and molecular changes appear conserved amongst different species and physiological states. Ultimately, these changes result in the reprioritization of fuel selection during heat stress, which appears to be primarily responsible for reduced ruminant animal productivity during the warm summer months.
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Affiliation(s)
- L H Baumgard
- Department of Animal Science, Iowa State University, Ames, IA, USA.
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9
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Shuai H, Zhang J, Zhang J, Xie J, Zhang M, Yu Y, Zhang L. Erythropoietin protects pancreatic β-cell line NIT-1 cells against cytokine-induced apoptosis via phosphatidylinositol 3-kinase/Akt signaling. Endocr Res 2011; 36:25-34. [PMID: 21226565 DOI: 10.3109/07435800.2010.534753] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Erythropoietin (EPO) is a cytokine that regulates the proliferation, differentiation, and survival of erythroid progenitor cells. EPO has recently been demonstrated to have a tissue-protective role by mediating anti-apoptotic signals through the erythropoietin receptor (EPOR) in various tissues, including brain, liver, and heart. We have previously examined pancreatic β-cell line NIT-1 cells for the expression of EPOR by real-time PCR and determined that these cells were protected by EPO against cytokine-induced apoptosis. The precise underlying anti-apoptotic mechanisms in pancreatic β-cells are poorly understood. The purpose of this study is to examine erythropoietin receptor expression in the NIT-1 pancreatic beta-cell line and the intracellular pathway related with its anti-apoptosis effect in NIT-1 cells. METHODS we examined the expression of EPOR by western blot. We investigate the role of erythropoietin in the survival of these cells, and whether the PI3K/AKT pathway is involved in this protective process. RESULTS NIT-1 cells expressed EPOR and, in the presence of certain cytokines, exposure of NIT-1 cells to recombinant human erythropoietin (rhEPO) significantly improved the impaired insulin secretion and inhibited cytokine-induced apoptosis. RhEPO caused a rapid activation of Akt and increased expression of Bcl-2. The protective anti-apoptotic effect of rhEPO was significantly abolished by a specific phosphatidylinositol 3-kiniase (PI3K) inhibitor, LY294002. CONCLUSIONS Our findings indicate that EPOR is expressed in pancreatic β-cell line NIT-1 cells and suggest that EPO may act as a survival factor requiring the PI3K/Akt pathway.
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Affiliation(s)
- Hongxia Shuai
- Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China
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Miller RS, Becker KG, Prabhu V, Cooke DW. Adipocyte gene expression is altered in formerly obese mice and as a function of diet composition. J Nutr 2008; 138:1033-8. [PMID: 18492830 PMCID: PMC2756972 DOI: 10.1093/jn/138.6.1033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the development of obesity, the source of excess energy may influence appetite and metabolism. To determine the effects of differences in diet composition in obesity, mice were fed either a high-carbohydrate diet (HC; 10% fat energy) or a high-fat energy-restricted diet (HFR; 60% fat energy) over 18 wk in weight-matched groups of mice. To identify obesity-associated genes with persistently altered expression following weight reduction, mice were fed either a standard low-fat diet (LF; 10% fat energy), an unrestricted high-fat diet (HF; 60% fat energy), or a HF diet followed by weight reduction (WR). Mice fed a HF diet had significantly greater gonadal fat mass and higher whole blood glucose concentrations than mice fed an HC diet. Of the mice fed a high-fat diet, total body weight and serum insulin concentrations were greater in HF than in HFR. Microarray analysis revealed that HF vs. HC feeding resulted in global differences in adipocyte gene expression patterns. Although we identified genes whose expression was altered in both moderately and severely obese mice, there were also a large number of genes with altered expression only in severe obesity. Formerly obese, WR mice did not differ significantly from lean controls in total body weight or physiological measures. However, microarray analysis revealed distinctly different patterns of adipocyte gene expression. Furthermore, there were 398 genes with altered expression in HF mice that persisted in WR mice. Genes with persistently altered expression following obesity may play a role in rebound weight gain following weight reduction.
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Affiliation(s)
- Ryan S. Miller
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, Ilyssa Center for Molecular and Cellular Endocrinology, Johns Hopkins University School of Medicine, Baltimore, MD 21287,To whom correspondence should be addressed. E-mail:
| | - Kevin G. Becker
- Gene Expression and Genomics Unit, National Institute on Aging, NIH, Baltimore, MD 21224
| | - Vinayakumar Prabhu
- Gene Expression and Genomics Unit, National Institute on Aging, NIH, Baltimore, MD 21224
| | - David W. Cooke
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, Ilyssa Center for Molecular and Cellular Endocrinology, Johns Hopkins University School of Medicine, Baltimore, MD 21287
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11
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Gene expression profiling of a mouse model of pancreatic islet dysmorphogenesis. PLoS One 2008; 3:e1611. [PMID: 18297134 PMCID: PMC2249940 DOI: 10.1371/journal.pone.0001611] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 01/16/2008] [Indexed: 12/24/2022] Open
Abstract
Background In the past decade, several transcription factors critical for pancreas organogenesis have been identified. Despite this success, many of the factors necessary for proper islet morphogenesis and function remain uncharacterized. Previous studies have shown that transgenic over-expression of the transcription factor Hnf6 specifically in the pancreatic endocrine cell lineage resulted in disruptions in islet morphogenesis, including dysfunctional endocrine cell sorting, increased individual islet size, increased number of peripheral endocrine cell types, and failure of islets to migrate away from the ductal epithelium. The mechanisms whereby maintained Hnf6 causes defects in islet morphogenesis have yet to be elucidated. Methodology/Principal Findings We exploited the dysmorphic islets in Hnf6 transgenic animals as a tool to identify factors important for islet morphogenesis. Genome-wide microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal total pancreas tissue from wild type and Hnf6 transgenic animals. Here we report the identification of genes with an altered expression in Hnf6 transgenic animals and highlight factors with potential importance in islet morphogenesis. Importantly, gene products involved in cell adhesion, cell migration, ECM remodeling and proliferation were found to be altered in Hnf6 transgenic pancreata, revealing specific candidates that can now be analyzed directly for their role in these processes during islet development. Conclusions/Significance This study provides a unique dataset that can act as a starting point for other investigators to explore the role of the identified genes in pancreatogenesis, islet morphogenesis and mature β cell function.
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Tweedie E, Artner I, Crawford L, Poffenberger G, Thorens B, Stein R, Powers AC, Gannon M. Maintenance of hepatic nuclear factor 6 in postnatal islets impairs terminal differentiation and function of beta-cells. Diabetes 2006; 55:3264-70. [PMID: 17130469 DOI: 10.2337/db06-0090] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The Onecut homeodomain transcription factor hepatic nuclear factor 6 (Hnf6) is necessary for proper development of islet beta-cells. Hnf6 is initially expressed throughout the pancreatic epithelium but is downregulated in endocrine cells at late gestation and is not expressed in postnatal islets. Transgenic mice in which Hnf6 expression is maintained in postnatal islets (pdx1(PB)Hnf6) show overt diabetes and impaired glucose-stimulated insulin secretion (GSIS) at weaning. We now define the mechanism whereby maintenance of Hnf6 expression postnatally leads to beta-cell dysfunction. We provide evidence that continued expression of Hnf6 impairs GSIS by altering insulin granule biosynthesis, resulting in a reduced response to secretagogues. Sustained expression of Hnf6 also results in downregulation of the beta-cell-specific transcription factor MafA and a decrease in total pancreatic insulin. These results suggest that downregulation of Hnf6 expression in beta-cells during development is essential to achieve a mature, glucose-responsive beta-cell.
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Affiliation(s)
- Elizabeth Tweedie
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, 2220 Pierce Ave., 746 PRB, Nashville, TN 37232-6303, USA
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13
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Kudo T, Wu J, Ogawa Y, Suga S, Hasegawa N, Suda T, Mizukami H, Yagihashi S, Wakui M. Novel mechanism of chronic exposure of oleic acid-induced insulin release impairment in rat pancreatic beta-cells. J Pharmacol Exp Ther 2006; 318:1203-10. [PMID: 16757537 DOI: 10.1124/jpet.106.105759] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A sustained, high circulating level of free fatty acids (FFAs) is an important risk factor for the development of insulin resistance, islet beta-cell dysfunction, and pathogenesis of type 2 diabetes. Here, we report a novel mechanism of chronic exposure of oleic acid (OA)-induced rat insulin release impairment. Following a 4-day exposure to 0.1 mM OA, there was no significant difference in basal insulin release when comparing OA-treated and untreated islets in the presence of 2.8 mM glucose, whereas 16.7 mM glucose-stimulated insulin release increased 2-fold in control, but not in OA-treated, islets. Perforated patch-clamp recordings showed that untreated beta-cells exhibited a resting potential of -62.1 +/- 0.9 mV and were electrically silent, whereas OA-treated beta-cells showed more positive resting potentials and spontaneous action potential firing. Cell-attached single-channel recordings revealed spontaneous opening of ATP-sensitive potassium (K(ATP)) channels in control, but not in OA-treated, beta-cells. Inside-out excised patch recordings showed similar activity in both OA-treated and untreated beta-cells in the absence of ATP on the inside of the cellular membrane, whereas in the presence of ATP, K(ATP) channel activity was significantly reduced in OA-treated beta-cells. Electron microscopy demonstrated that chronic exposure to OA resulted in the accumulation of triglycerides in beta-cell cytoplasm and reduced both the number of insulin-containing granules and insulin content. Collectively, chronic exposure to OA closed K(ATP) channels by increasing the sensitivity of K(ATP) channels to ATP, which in turn led to the continuous excitation of beta-cells, depletion of insulin storage, and impairment of glucose-stimulated insulin release.
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Affiliation(s)
- Takanori Kudo
- Third Department of Internal Medicine, Hirosaki University School of Medicine, Japan
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14
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Musso G, Gambino R, Biroli G, Carello M, Fagà E, Pacini G, De Michieli F, Cassader M, Durazzo M, Rizzetto M, Pagano G. Hypoadiponectinemia predicts the severity of hepatic fibrosis and pancreatic Beta-cell dysfunction in nondiabetic nonobese patients with nonalcoholic steatohepatitis. Am J Gastroenterol 2005; 100:2438-46. [PMID: 16279898 DOI: 10.1111/j.1572-0241.2005.00297.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES The relationships between the adipokines tumor necrosis factor (TNF)-alpha and adiponectin and the parameters of glucose homeostasis and severity of liver disease were assessed in nonobese nondiabetic subjects with nonalcoholic steatohepatitis (NASH). METHODS A frequently sampled intravenous glucose tolerance test, serum cytokine measurement, and 7-day alimentary record were performed in 20 biopsy-proven NASH patients and 45 age-, sex-, and BMI-matched controls (30 insulin sensitive and 15 insulin resistant). RESULTS Patients with NASH had impaired pancreatic beta-cell function compared with both insulin-sensitive (adaptation index, AI: 97.7 +/- 17.7 vs 307.4 +/- 24.1 min(-2) mmol(-1) L; p= 0.00001) and insulin-resistant (adaptation index, AI: 97.7 +/- 17.7 vs 201.4 +/- 41.1 min(-2) mmol(-1) L; p= 0.001) controls. Serum adiponectin levels were also significantly lower in the NASH group than in the two control groups and correlated with adaptation index and with the severity of hepatic steatosis, necroinflammation, and fibrosis. When NASH patients were grouped according to the severity of histological liver damage, adiponectin was the only variable discriminating patients with higher necroinflammatory grade and fibrosis score from those with milder lesions. CONCLUSIONS Beta-cell secretory impairment is present in nonobese patients with NASH before glucose intolerance appears and may contribute to their increased risk for developing diabetes. Hypoadiponectinemia is a feature of NASH and may have a pathogenetic role in beta-cell dysfunction and in hepatic necroinflammation and fibrosis, independently of insulin resistance, visceral fat accumulation, TNF-alpha axis activity, and dietary habits. Our findings provide further rationale for therapeutic approaches aimed at increasing adiponectin levels together with restoring beta-cell function and insulin sensitivity.
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Affiliation(s)
- Giovanni Musso
- Department of Internal Medicine, University of Turin, Italy
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Biden TJ, Robinson D, Cordery D, Hughes WE, Busch AK. Chronic effects of fatty acids on pancreatic beta-cell function: new insights from functional genomics. Diabetes 2004; 53 Suppl 1:S159-65. [PMID: 14749282 DOI: 10.2337/diabetes.53.2007.s159] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Type 2 diabetes can be viewed as a failure of the pancreatic beta-cell to compensate for peripheral insulin resistance with enhanced insulin secretion. This failure is explained by both a relative loss of beta-cell mass as well as secretory defects that include enhanced basal secretion and a selective loss of sensitivity to glucose. These features are reproduced by chronic exposure of beta-cells to fatty acids (FAs), suggesting that hyperlipidemia might contribute to decompensation. Using MIN6 cells pretreated for 48 h with oleate or palmitate, we have previously defined alterations in global gene expression by transcript profiling and described additional secretory changes to those already established (Busch A-K, Cordery D, Denyer G, Biden TJ: Diabetes 51:977-987, 2002). In contrast to a modest decoupling of glucose-stimulated insulin secretion, FA pretreatment markedly enhanced the secretory response to an acute subsequent challenge with FAs. We propose that this apparent switch in sensitivity from glucose to FAs would be an appropriate response to hyperlipidemia in vivo and thus plays a positive role in beta-cell compensation for insulin resistance. Altered expression of dozens of genes could contribute to this switch, and allelic variations in any of these genes could (to varying degrees) impair beta-cell compensation and thus contribute to conditions ranging from impaired glucose tolerance to frank diabetes.
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Affiliation(s)
- Trevor J Biden
- Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, Australia.
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Okuyama R, Fujiwara T, Ohsumi J. High glucose potentiates palmitate-induced NO-mediated cytotoxicity through generation of superoxide in clonal beta-cell HIT-T15. FEBS Lett 2003; 545:219-23. [PMID: 12804779 DOI: 10.1016/s0014-5793(03)00534-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Prolonged exposure to free fatty acids induces beta-cell cytotoxicity. We investigated whether this fatty-acid-induced cytotoxicity is affected by high glucose levels. In clonal beta-cell HIT-T15, palmitate-induced cytotoxicity was potentiated depending on elevated glucose concentrations due to increased apoptosis without cytotoxic effects of high glucose per se. This palmitate cytotoxicity was blocked by NO synthase inhibitors, and palmitate actually increased cellular NO production. The potentiation of palmitate cytotoxicity under high glucose was reversed by decreasing superoxide production, suggesting that superoxide overproduction under high glucose enhances NO-mediated cytotoxicity in beta-cells, which may explain the mechanism of synergistic deterioration of pancreatic beta-cells by free fatty acids and high glucose.
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Affiliation(s)
- Ryo Okuyama
- Pharmacology and Molecular Biology Research Laboratories, Sankyo Co. Ltd., 2-58 Hiromachi-1-chome, Shinagawa-ku, 140-8710, Tokyo, Japan.
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Berná G, León-Quinto T, Fuentes E, Andreu E, Nadal A, Roche E, Martín F, Reig JA, Soria B. [Cellular engineering and diabetes mellitus]. Rev Clin Esp 2001; 201:548-56. [PMID: 11692416 DOI: 10.1016/s0014-2565(01)70908-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- G Berná
- Instituto de Bioingeniería, Universidad Miguel Hernández de Elche. Alicante, 03550 San Juan, Alicante.
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