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Mukhuty A, Mandal S, Fouzder C, Das S, Chattopadhyay D, Majumdar T, Kundu R. Nrf2 inhibition regulates intracellular lipid accumulation in mouse insulinoma cells and improves insulin secretory function. Mol Cell Endocrinol 2024; 581:112112. [PMID: 38000461 DOI: 10.1016/j.mce.2023.112112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/11/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023]
Abstract
High amount of fat in the pancreas is linked to poor functioning of β-cells and raises the risk of type 2 diabetes. Here we report the putative role of a circulatory glycoprotein Fetuin-A, a known obesity marker, in promoting lipid accumulation in β-cells and its association with Fatty acid translocase/CD36 for lipid storage culminate in β-cell dysfunction. Additionally, this work reveals regulation of CD36 via Nrf2, a key regulator of oxidative stress, and reduction of lipid accumulation by suppression of Nrf2 that restores β-cell function. Palmitate (0.50 mM) and Fetuin-A (100 μg/mL) exposure showed high levels of intracellular lipid in MIN6 (mouse insulinoma cells) with a concomitant decrease in insulin secretion. This also increased the expression of important lipogenic factors, like CD36, PGC1α, PPARγ, and SREBP1. Flow cytometry analysis of CD36 membrane localization has been corroborated with an increased accumulation of lipids as indicated by Oil-Red-O staining. Immunoblotting and immunofluorescence of Nrf2 indicated its high expression in palmitate-fetuin-A incubation and translocation in the nucleus. Suppression of Nrf2 by siRNA showed a reduced expression of lipogenic genes, ablation of lipid droplets, decrease in the number of apoptotic cells, and restoration of insulin secretion with a corresponding increase of Pdx1, BETA2, and Ins1 gene expression. Our study thus suggested an important aspect of lipid accumulation in the pancreatic β-cells contributing to β-cell dysfunction and demonstrated the role of Fetuin-A in CD36 expression, with a possible way of restoring β-cell function by targeting Nrf2.
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Affiliation(s)
- Alpana Mukhuty
- Cell Signaling Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India
| | - Samanwita Mandal
- Cell Signaling Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India
| | - Chandrani Fouzder
- Cell Signaling Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India
| | - Snehasis Das
- Cellular and Molecular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India
| | - Dipanjan Chattopadhyay
- Cellular and Molecular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India
| | - Tanmay Majumdar
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Rakesh Kundu
- Cell Signaling Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan, 731 235, India.
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Kuriyama T, Ishibashi C, Kozawa J, Baden MY, Horii T, Niki A, Ozawa H, Hosokawa Y, Fujita Y, Sadahiro K, Satoh T, Hamaguchi T, Shimomura I. Effects of liraglutide on intrapancreatic fat deposition in patients with type 2 diabetes. Clin Nutr ESPEN 2024; 59:208-213. [PMID: 38220377 DOI: 10.1016/j.clnesp.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 01/16/2024]
Abstract
BACKGROUND & AIMS Ectopic fat deposition is associated with worsening of glycemic control. This study was conducted to determine whether liraglutide reduces ectopic fat deposition, especially in pancreas, in patients with type 2 diabetes (T2D). METHODS We retrospectively recruited T2D patients who underwent abdominal unenhanced CT scans both before and after administration of liraglutide (N = 13) or glimepiride (N = 29). Using CT values of pancreas (P), liver (L) and spleen (S), we defined the indices of intrapancreatic and liver fat as P-S value and L-S value, respectively. Increase of each value suggests the reduction of each fat deposition. RESULTS The values of HbA1c (p = 0.0017) and body weight (p = 0.0081) decreased, and L-S (p = 0.0024) increased significantly after administration of liraglutide compared with those at baseline. Similarly, P-S tended to increase in the liraglutide group (p = 0.0547) and increased significantly in the liraglutide subgroup with fatty pancreas (p = 0.0303), defined as having baseline P-S less than -5. In the glimepiride group, P-S did not increase regardless of baseline P-S. Among patients with fatty pancreas, administration of liraglutide tended to be a significant factor for the change in P-S after adjustment for the change in HbA1c (p = 0.1090) and the change in visceral fat area (p = 0.1030). CONCLUSIONS Intrapancreatic fat deposition was decreased after treatment with liraglutide, but not glimepiride, in T2D patients with fatty pancreas. Liraglutide might reduce intrapancreatic fat deposition independently of decreases in HbA1c and visceral fat volume.
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Affiliation(s)
- Tsukasa Kuriyama
- Division of Diabetes, Department of Internal Medicine, Itami City Hospital, Itami, Hyogo, Japan; Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Chisaki Ishibashi
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Junji Kozawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan; Department of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita, Japan.
| | - Megu Y Baden
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan; Department of Lifestyle Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Tomomi Horii
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Akiko Niki
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Harutoshi Ozawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan; Department of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yoshiya Hosokawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Yukari Fujita
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Katsuhiko Sadahiro
- Division of Diabetes, Department of Internal Medicine, Itami City Hospital, Itami, Hyogo, Japan
| | - Tomomi Satoh
- Division of Diabetes, Department of Internal Medicine, Itami City Hospital, Itami, Hyogo, Japan
| | - Tomoya Hamaguchi
- Division of Diabetes, Department of Internal Medicine, Itami City Hospital, Itami, Hyogo, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
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Thomas P, Gallagher MT, Da Silva Xavier G. Beta cell lipotoxicity in the development of type 2 diabetes: the need for species-specific understanding. Front Endocrinol (Lausanne) 2023; 14:1275835. [PMID: 38144558 PMCID: PMC10739424 DOI: 10.3389/fendo.2023.1275835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/13/2023] [Indexed: 12/26/2023] Open
Abstract
The propensity to develop type 2 diabetes (T2D) is known to have both environmental and hereditary components. In those with a genetic predisposition to T2D, it is widely believed that elevated concentrations of circulatory long-chain fatty acids (LC-FFA) significantly contribute towards the demise of insulin-producing pancreatic β-cells - the fundamental feature of the development of T2D. Over 25 years of research support that LC-FFA are deleterious to β-cells, through a process termed lipotoxicity. However, the work underpinning the theory of β-cell lipotoxicity is mostly based on rodent studies. Doubts have been raised as to whether lipotoxicity also occurs in humans. In this review, we examine the evidence, both in vivo and in vitro, for the pathogenic effects of LC-FFA on β-cell viability and function in humans, highlighting key species differences. In this way, we aim to uncover the role of lipotoxicity in the human pathogenesis of T2D and motivate the need for species-specific understanding.
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Affiliation(s)
- Patricia Thomas
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| | - Meurig T. Gallagher
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| | - Gabriela Da Silva Xavier
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
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Pavlíková N, Šrámek J, Jaček M, Kovář J, Němcová V. Targets for pollutants in rat and human pancreatic beta-cells: The effect of prolonged exposure to sub-lethal concentrations of hexachlorocyclohexane isomers on the expression of function- and survival-related proteins. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2023; 104:104299. [PMID: 37865351 DOI: 10.1016/j.etap.2023.104299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/12/2023] [Accepted: 10/17/2023] [Indexed: 10/23/2023]
Abstract
Decades after most countries banned hexachlorocyclohexane, HCH isomers still pollute the environment. Many studies described HCH as a pro-diabetic factor; nevertheless, the effect of HCH isomers on pancreatic beta-cells remains unexplored. This study investigated the effects of a one-month exposure to α-HCH, β-HCH, and γ-HCH on protein expression in human (NES2Y) and rat (INS1E) pancreatic beta-cell lines. α-HCH and γ-HCH increased proinsulin and insulin levels in INS1E cells, while β-HCH showed the opposite trend. α-HCH altered the expression of PKA, ATF3, and PLIN2. β-HCH affected the expression of GLUT1, GLUT2, PKA, ATF3, p-eIF2α, ATP-CL, and PLIN2. γ-HCH altered the expression of PKA, ATF3, PLIN2, PLIN5, and IDH1. From the tested proteins, PKA, ATF3, and PLIN-2 were the most sensitive to HCH exposure and have the potential to be used as biomarkers.
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Affiliation(s)
- Nela Pavlíková
- Departement of Biochemistry, Cell and Molecular Biology & Center for Research on Nutrition, Metabolism, and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
| | - Jan Šrámek
- Departement of Biochemistry, Cell and Molecular Biology & Center for Research on Nutrition, Metabolism, and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Martin Jaček
- Department of Hygiene, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague 10, Czech Republic
| | - Jan Kovář
- Departement of Biochemistry, Cell and Molecular Biology & Center for Research on Nutrition, Metabolism, and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Vlasta Němcová
- Departement of Biochemistry, Cell and Molecular Biology & Center for Research on Nutrition, Metabolism, and Diabetes, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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5
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Chen S, Huang X. Cytosolic lipolysis in non-adipose tissues: energy provision and beyond. FEBS J 2022; 289:7385-7398. [PMID: 34407292 DOI: 10.1111/febs.16161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/18/2021] [Accepted: 08/17/2021] [Indexed: 12/16/2022]
Abstract
Cytosolic lipolysis is a well-defined biochemical process that plays important roles in the mobilization of stored neutral lipids. Lipid turnover, regulated by cytosolic lipolysis, has been extensively studied in adipose tissue, liver, and muscle. The storage and utilization of neutral lipids is a basic function of most, if not all, tissues and cells. In this review, we focus on the functions of cytosolic lipolysis mainly in non-adipose tissues and in several physiological processes, including cancer, longevity, and pathogen infection. The mechanisms underlying the impact of cytosolic lipolysis on these events will be discussed. Detailed understanding of cytosolic lipolysis in both adipose and non-adipose tissues will have implications for future clinical translation.
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Affiliation(s)
- Siyu Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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6
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Impact of Dysfunctional Adipose Tissue Depots on the Cardiovascular System. Int J Mol Sci 2022; 23:ijms232214296. [PMID: 36430774 PMCID: PMC9695168 DOI: 10.3390/ijms232214296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
Obesity with its associated complications represents a social, economic and health problem of utmost importance worldwide. Specifically, obese patients carry a significantly higher risk of developing cardiovascular disease compared to nonobese individuals. Multiple molecular mechanisms contribute to the impaired biological activity of the distinct adipose tissue depots in obesity, including secretion of proinflammatory mediators and reactive oxygen species, ultimately leading to an unfavorable impact on the cardiovascular system. This review summarizes data relating to the contribution of the main adipose tissue depots, including both remote (i.e., intra-abdominal, hepatic, skeletal, pancreatic, renal, and mesenteric adipose fat), and cardiac (i.e., the epicardial fat) adipose locations, on the cardiovascular system. Finally, we discuss both pharmacological and non-pharmacological strategies aimed at reducing cardiovascular risk through acting on adipose tissues, with particular attention to the epicardial fat.
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7
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Approaches to Measuring the Activity of Major Lipolytic and Lipogenic Enzymes In Vitro and Ex Vivo. Int J Mol Sci 2022; 23:ijms231911093. [PMID: 36232405 PMCID: PMC9570359 DOI: 10.3390/ijms231911093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 11/17/2022] Open
Abstract
Since the 1950s, one of the goals of adipose tissue research has been to determine lipolytic and lipogenic activity as the primary metabolic pathways affecting adipocyte health and size and thus representing potential therapeutic targets for the treatment of obesity and associated diseases. Nowadays, there is a relatively large number of methods to measure the activity of these pathways and involved enzymes, but their applicability to different biological samples is variable. Here, we review the characteristics of mean lipogenic and lipolytic enzymes, their inhibitors, and available methodologies for assessing their activity, and comment on the advantages and disadvantages of these methodologies and their applicability in vivo, ex vivo, and in vitro, i.e., in cells, organs and their respective extracts, with the emphasis on adipocytes and adipose tissue.
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8
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Zhang R, Meng J, Yang S, Liu W, Shi L, Zeng J, Chang J, Liang B, Liu N, Xing D. Recent Advances on the Role of ATGL in Cancer. Front Oncol 2022; 12:944025. [PMID: 35912266 PMCID: PMC9326118 DOI: 10.3389/fonc.2022.944025] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 06/15/2022] [Indexed: 12/22/2022] Open
Abstract
The hypoxic state of the tumor microenvironment leads to reprogramming lipid metabolism in tumor cells. Adipose triglyceride lipase, also known as patatin-like phospholipase= domain-containing protein 2 and Adipose triglyceride lipase (ATGL), as an essential lipid metabolism-regulating enzyme in cells, is regulated accordingly under hypoxia induction. However, studies revealed that ATGL exhibits both tumor-promoting and tumor-suppressing effects, which depend on the cancer cell type and the site of tumorigenesis. For example, elevated ATGL expression in breast cancer is accompanied by enhanced fatty acid oxidation (FAO), enhancing cancer cells’ metastatic ability. In prostate cancer, on the other hand, tumor activity tends to be negatively correlated with ATGL expression. This review outlined the regulation of ATGL-mediated lipid metabolism pathways in tumor cells, emphasizing the Hypoxia-inducible factors 1 (HIF-1)/Hypoxia-inducible lipid droplet-associated (HIG-2)/ATGL axis, peroxisome proliferator-activated receptor (PPAR)/G0/G1 switch gene 2 (G0S2)/ATGL axis, and fat-specific protein 27 (FSP-27)/Early growth response protein 1 (EGR-1)/ATGL axis. In the light of recent research on different cancer types, the role of ATGL on tumorigenesis, tumor proliferation, and tumor metastasis was systemically reviewed.
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Affiliation(s)
- Renshuai Zhang
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Jingsen Meng
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Shanbo Yang
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Wenjing Liu
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Lingyu Shi
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Jun Zeng
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Jing Chang
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Bing Liang
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
| | - Ning Liu
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
- *Correspondence: Ning Liu, ; Dongming Xing,
| | - Dongming Xing
- Cancer Institute, The Affiliated Hospital of Qingdao University, Qingdao, China
- Qingdao Cancer Institute, Qingdao, China
- School of Life Sciences, Tsinghua University, Beijing, China
- *Correspondence: Ning Liu, ; Dongming Xing,
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O’Malley Y, Coleman MC, Sun X, Lei J, Yao J, Pulliam CF, Kluz P, McCormick ML, Yi Y, Imai Y, Engelhardt JF, Norris AW, Spitz DR, Uc A. Oxidative stress and impaired insulin secretion in cystic fibrosis pig pancreas. ADVANCES IN REDOX RESEARCH 2022; 5:100040. [PMID: 35903252 PMCID: PMC9328447 DOI: 10.1016/j.arres.2022.100040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cystic fibrosis-related diabetes (CFRD) is one the most common comorbidities in cystic fibrosis (CF). Pancreatic oxidative stress has been postulated in the pathogenesis of CFRD, but no studies have been done to show an association. The main obstacle is the lack of suitable animal models and no immediate availability of pancreas tissue in humans. In the CF porcine model, we found increased pancreatic total glutathione (GSH), glutathione disulfide (GSSG), 3-nitrotyrosine- and 4-hydroxynonenal-modified proteins, and decreased copper zinc superoxide dismutase (CuZnSOD) activity, all indicative of oxidative stress. CF pig pancreas demonstrated increased DHE oxidation (as a surrogate marker of superoxide) in situ compared to non-CF and this was inhibited by a SOD-mimetic (GC4401). Catalase and glutathione peroxidase activities were not different between CF and non-CF pancreas. Isolated CF pig islets had significantly increased DHE oxidation, peroxide production, reduced insulin secretion in response to high glucose and diminished secretory index compared to non-CF islets. Acute treatment with apocynin or an SOD mimetic failed to restore insulin secretion. These results are consistent with the hypothesis that CF pig pancreas is under significant oxidative stress as a result of increased O2 ●- and peroxides combined with reduced antioxidant defenses against reactive oxygen species (ROS). We speculate that insulin secretory defects in CF may be due to oxidative stress.
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Affiliation(s)
- Yunxia O’Malley
- Stead Family Department of Pediatrics, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
| | - Mitchell C. Coleman
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Xingshen Sun
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa 52242, USA
| | - Junying Lei
- Stead Family Department of Pediatrics, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
| | - Jianrong Yao
- Stead Family Department of Pediatrics, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
| | - Casey F. Pulliam
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Paige Kluz
- Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, Iowa 52242, USA
| | - Michael L. McCormick
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Yaling Yi
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa 52242, USA
| | - Yumi Imai
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - John F. Engelhardt
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa 52242, USA
| | - Andrew W. Norris
- Stead Family Department of Pediatrics, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Douglas R. Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Aliye Uc
- Stead Family Department of Pediatrics, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa 52242, USA
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa 52242, USA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
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10
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Lipid metabolism and neutrophil function. Cell Immunol 2022; 377:104546. [DOI: 10.1016/j.cellimm.2022.104546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/22/2022]
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Tong X, Liu S, Stein R, Imai Y. Lipid Droplets' Role in the Regulation of β-Cell Function and β-Cell Demise in Type 2 Diabetes. Endocrinology 2022; 163:6516108. [PMID: 35086144 PMCID: PMC8826878 DOI: 10.1210/endocr/bqac007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Indexed: 01/29/2023]
Abstract
During development of type 2 diabetes (T2D), excessive nutritional load is thought to expose pancreatic islets to toxic effects of lipids and reduce β-cell function and mass. However, lipids also play a positive role in cellular metabolism and function. Thus, proper trafficking of lipids is critical for β cells to maximize the beneficial effects of these molecules while preventing their toxic effects. Lipid droplets (LDs) are organelles that play an important role in the storage and trafficking of lipids. In this review, we summarize the discovery of LDs in pancreatic β cells, LD lifecycle, and the effect of LD catabolism on β-cell insulin secretion. We discuss factors affecting LD formation such as age, cell type, species, and nutrient availability. We then outline published studies targeting critical LD regulators, primarily in rat and human β-cell models, to understand the molecular effect of LD formation and degradation on β-cell function and health. Furthermore, based on the abnormal LD accumulation observed in human T2D islets, we discuss the possible role of LDs during the development of β-cell failure in T2D. Current knowledge indicates that proper formation and clearance of LDs are critical to normal insulin secretion, endoplasmic reticulum homeostasis, and mitochondrial integrity in β cells. However, it remains unclear whether LDs positively or negatively affect human β-cell demise in T2D. Thus, we discuss possible research directions to address the knowledge gap regarding the role of LDs in β-cell failure.
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Affiliation(s)
- Xin Tong
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Siming Liu
- Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Roland Stein
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Yumi Imai
- Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
- Iowa City Veterans Affairs Medical Center, Iowa City, Iowa 52246, USA
- Correspondence: Yumi Imai, MD, Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, 200 Hawkins Dr, PBDB Rm 3318, Iowa City, IA 52242, USA.
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12
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Horii T, Kozawa J, Fujita Y, Kawata S, Ozawa H, Ishibashi C, Yoneda S, Nammo T, Miyagawa JI, Eguchi H, Shimomura I. Lipid droplet accumulation in β cells in patients with type 2 diabetes is associated with insulin resistance, hyperglycemia and β cell dysfunction involving decreased insulin granules. Front Endocrinol (Lausanne) 2022; 13:996716. [PMID: 36204103 PMCID: PMC9530467 DOI: 10.3389/fendo.2022.996716] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Pancreatic fat is a form of ectopic fat. Lipid droplets (LDs) are also observed in β cells; however, the pathophysiological significance, especially for β cell function, has not been elucidated. Our aim was to assess LD accumulation in β cells in various stages of glucose intolerance and to clarify its relationship with clinical and histological parameters. METHODS We examined 42 Japanese patients who underwent pancreatectomy. The BODIPY493/503-positive (BODIPY-positive) area in β cells was measured in pancreatic sections from 32 patients. The insulin granule numbers were counted in an additional 10 patients using electron microscopy. RESULTS The BODIPY-positive area in β cells in preexisting type 2 diabetes patients was higher than that in normal glucose tolerance patients (p = 0.031). The BODIPY-positive area in β cells was positively correlated with age (r = 0.45, p = 0.0097), HbA1c (r = 0.38, p = 0.0302), fasting plasma glucose (r = 0.37, p = 0.045), and homeostasis model assessment insulin resistance (r = 0.41, p = 0.049) and negatively correlated with an increase in the C-peptide immunoreactivity level by the glucagon test (r = -0.59, p = 0.018). The ratio of mature insulin granule number to total insulin granule number was reduced in the patients with rich LD accumulation in β cells (p = 0.039). CONCLUSIONS Type 2 diabetes patients had high LD accumulation in β cells, which was associated with insulin resistance, hyperglycemia, aging and β cell dysfunction involving decreased mature insulin granules.
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Affiliation(s)
- Tomomi Horii
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Junji Kozawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- *Correspondence: Junji Kozawa,
| | - Yukari Fujita
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Community Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Satoshi Kawata
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Harutoshi Ozawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Lifestyle Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Chisaki Ishibashi
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Sho Yoneda
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- Yoneda Clinic, Osaka, Japan
| | - Takao Nammo
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | | | - Hidetoshi Eguchi
- Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
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13
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Grabner GF, Xie H, Schweiger M, Zechner R. Lipolysis: cellular mechanisms for lipid mobilization from fat stores. Nat Metab 2021; 3:1445-1465. [PMID: 34799702 DOI: 10.1038/s42255-021-00493-6] [Citation(s) in RCA: 203] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022]
Abstract
The perception that intracellular lipolysis is a straightforward process that releases fatty acids from fat stores in adipose tissue to generate energy has experienced major revisions over the last two decades. The discovery of new lipolytic enzymes and coregulators, the demonstration that lipophagy and lysosomal lipolysis contribute to the degradation of cellular lipid stores and the characterization of numerous factors and signalling pathways that regulate lipid hydrolysis on transcriptional and post-transcriptional levels have revolutionized our understanding of lipolysis. In this review, we focus on the mechanisms that facilitate intracellular fatty-acid mobilization, drawing on canonical and noncanonical enzymatic pathways. We summarize how intracellular lipolysis affects lipid-mediated signalling, metabolic regulation and energy homeostasis in multiple organs. Finally, we examine how these processes affect pathogenesis and how lipolysis may be targeted to potentially prevent or treat various diseases.
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Affiliation(s)
- Gernot F Grabner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Hao Xie
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Martina Schweiger
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
| | - Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Graz, Austria.
- BioTechMed-Graz, Graz, Austria.
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14
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Langlois A, Forterre A, Pinget M, Bouzakri K. Impact of moderate exercise on fatty acid oxidation in pancreatic β-cells and skeletal muscle. J Endocrinol Invest 2021; 44:1815-1825. [PMID: 33844166 PMCID: PMC8357749 DOI: 10.1007/s40618-021-01551-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/03/2021] [Indexed: 12/13/2022]
Abstract
Fatty acids (FA) play a crucial role in glycaemia regulation in healthy and metabolic disorders conditions through various mechanisms. FA oxidation is one of the processes involved in lipid metabolism and can be modulated by exercise. Nowadays, physical activity is known to be an effective strategy for the prevention and treatment of Type 2 Diabetes. Moreover, its intensity, its duration, the sex-gender, the prandial state, exerkines… are as many parameters that can influence glycaemic control. However, the widely debated question is to determine the best type of exercise for patients with metabolic disorders. In this review, we will discuss the impact of exercise intensity, especially moderate activity, on glycaemic control by focussing on FA oxidation in pancreatic β-cells and skeletal muscle. Finally, thanks to all the recent data, we will determine whether moderate physical activity is a good therapeutic strategy and if FA oxidation represents a target of interest to treat diabetic, obese and insulin-resistant patients.
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Affiliation(s)
- A Langlois
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - A Forterre
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - M Pinget
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France
| | - K Bouzakri
- Centre Européen D'étude du Diabète, Unité Mixte de Recherche de L'Université de Strasbourg « Diabète et Thérapeutique », Strasbourg, France.
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15
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Pearson GL, Gingerich MA, Walker EM, Biden TJ, Soleimanpour SA. A Selective Look at Autophagy in Pancreatic β-Cells. Diabetes 2021; 70:1229-1241. [PMID: 34016598 PMCID: PMC8275885 DOI: 10.2337/dbi20-0014] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/22/2021] [Indexed: 12/15/2022]
Abstract
Insulin-producing pancreatic β-cells are central to glucose homeostasis, and their failure is a principal driver of diabetes development. To preserve optimal health β-cells must withstand both intrinsic and extrinsic stressors, ranging from inflammation to increased peripheral insulin demand, in addition to maintaining insulin biosynthesis and secretory machinery. Autophagy is increasingly being appreciated as a critical β-cell quality control system vital for glycemic control. Here we focus on the underappreciated, yet crucial, roles for selective and organelle-specific forms of autophagy as mediators of β-cell health. We examine the unique molecular players underlying each distinct form of autophagy in β-cells, including selective autophagy of mitochondria, insulin granules, lipid, intracellular amyloid aggregates, endoplasmic reticulum, and peroxisomes. We also describe how defects in selective autophagy pathways contribute to the development of diabetes. As all forms of autophagy are not the same, a refined view of β-cell selective autophagy may inform new approaches to defend against the various insults leading to β-cell failure in diabetes.
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Affiliation(s)
- Gemma L Pearson
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | | | - Emily M Walker
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | | | - Scott A Soleimanpour
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Veterans Affairs Ann Arbor Health Care System, Ann Arbor, MI
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16
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Mishra A, Liu S, Promes J, Harata M, Sivitz W, Fink B, Bhardwaj G, O'Neill BT, Kang C, Sah R, Strack S, Stephens S, King T, Jackson L, Greenberg AS, Anokye-Danso F, Ahima RS, Ankrum J, Imai Y. Perilipin 2 downregulation in β cells impairs insulin secretion under nutritional stress and damages mitochondria. JCI Insight 2021; 6:144341. [PMID: 33784258 PMCID: PMC8262280 DOI: 10.1172/jci.insight.144341] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/24/2021] [Indexed: 12/15/2022] Open
Abstract
Perilipin 2 (PLIN2) is a lipid droplet (LD) protein in β cells that increases under nutritional stress. Downregulation of PLIN2 is often sufficient to reduce LD accumulation. To determine whether PLIN2 positively or negatively affects β cell function under nutritional stress, PLIN2 was downregulated in mouse β cells, INS1 cells, and human islet cells. β Cell–specific deletion of PLIN2 in mice on a high-fat diet reduced glucose-stimulated insulin secretion (GSIS) in vivo and in vitro. Downregulation of PLIN2 in INS1 cells blunted GSIS after 24-hour incubation with 0.2 mM palmitic acid. Downregulation of PLIN2 in human pseudoislets cultured at 5.6 mM glucose impaired both phases of GSIS, indicating that PLIN2 is critical for GSIS. Downregulation of PLIN2 decreased specific OXPHOS proteins in all 3 models and reduced oxygen consumption rates in INS1 cells and mouse islets. Moreover, we found that PLIN2-deficient INS1 cells increased the distribution of a fluorescent oleic acid analog to mitochondria and showed signs of mitochondrial stress, as indicated by susceptibility to fragmentation and alterations of acyl-carnitines and glucose metabolites. Collectively, PLIN2 in β cells has an important role in preserving insulin secretion, β cell metabolism, and mitochondrial function under nutritional stress.
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Affiliation(s)
- Akansha Mishra
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Siming Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Joseph Promes
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Mikako Harata
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - William Sivitz
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian Fink
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Gourav Bhardwaj
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Brian T O'Neill
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Chen Kang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rajan Sah
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Samuel Stephens
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Timothy King
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Laura Jackson
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Andrew S Greenberg
- Obesity and Metabolism Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA
| | | | - Rexford S Ahima
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - James Ankrum
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Yumi Imai
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
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17
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Friedlander MSH, Nguyen VM, Kim SK, Bevacqua RJ. Pancreatic Pseudoislets: An Organoid Archetype for Metabolism Research. Diabetes 2021; 70:1051-1060. [PMID: 33947722 PMCID: PMC8343609 DOI: 10.2337/db20-1115] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/20/2021] [Indexed: 01/08/2023]
Abstract
Pancreatic islets are vital endocrine regulators of systemic metabolism, and recent investigations have increasingly focused on understanding human islet biology. Studies of isolated human islets have advanced understanding of the development, function, and regulation of cells comprising islets, especially pancreatic α- and β-cells. However, the multicellularity of the intact islet has stymied specific experimental approaches-particularly in genetics and cell signaling interrogation. This barrier has been circumvented by the observation that islet cells can survive dispersion and reaggregate to form "pseudoislets," organoids that retain crucial physiological functions, including regulated insulin and glucagon secretion. Recently, exciting advances in the use of pseudoislets for genetics, genomics, islet cell transplantation, and studies of intraislet signaling and islet cell interactions have been reported by investigators worldwide. Here we review molecular and cellular mechanisms thought to promote islet cell reaggregation, summarize methods that optimize pseudoislet development, and detail recent insights about human islet biology from genetic and transplantation-based pseudoislet experiments. Owing to robust, international programs for procuring primary human pancreata, pseudoislets should serve as both a durable paradigm for primary organoid studies and as an engine of discovery for islet biology, diabetes, and metabolism research.
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Affiliation(s)
- Mollie S H Friedlander
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
| | - Vy M Nguyen
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
| | - Seung K Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA
- JDRF Center of Excellence, Stanford University School of Medicine, Stanford, CA
| | - Romina J Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
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18
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Kozawa J, Shimomura I. Ectopic Fat Accumulation in Pancreas and Heart. J Clin Med 2021; 10:1326. [PMID: 33806978 PMCID: PMC8004936 DOI: 10.3390/jcm10061326] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/14/2021] [Accepted: 03/22/2021] [Indexed: 12/15/2022] Open
Abstract
Ectopic fat is found in liver, muscle, and kidney and is known to accumulate as visceral fat. In recent years, ectopic fat has also been observed in the pancreas, and it has been said that pancreatic fat accumulation is related to the pathophysiology of diabetes and the onset of diabetes, but the relationship has not yet been determined. In the heart, epicardium fat is another ectopic fat, which is associated with the development of coronary artery disease. Ectopic fat is also observed in the myocardium, and diabetic patients have more fat accumulation in this tissue than nondiabetic patients. Myocardium fat is reported to be related to diastolic cardiac dysfunction, which is one of the characteristics of the complications observed in diabetic patients. We recently reported that ectopic fat accumulation was observed in coronary arteries of a type 2 diabetic patient with intractable coronary artery disease, and coronary artery is attracting attention as a new tissue of ectopic fat accumulation. Here, we summarize the latest findings focusing on the relationship between ectopic fat accumulation in these organs and diabetic pathophysiology and complications, then describe the possibility of future treatments targeting these ectopic fat accumulations.
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Affiliation(s)
- Junji Kozawa
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan;
- Department of Diabetes Care Medicine, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan;
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19
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Wang K, Cui Y, Lin P, Yao Z, Sun Y. JunD Regulates Pancreatic β-Cells Function by Altering Lipid Accumulation. Front Endocrinol (Lausanne) 2021; 12:689845. [PMID: 34335468 PMCID: PMC8322846 DOI: 10.3389/fendo.2021.689845] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/04/2021] [Indexed: 12/28/2022] Open
Abstract
The impairment of pancreatic β-cells function is partly caused by lipotoxicity, which aggravates the development of type 2 diabetes mellitus. Activator Protein 1 member JunD modulates apoptosis and oxidative stress. Recently, it has been found that JunD regulates lipid metabolism in hepatocytes and cardiomyocytes. Here, we studied the role of JunD in pancreatic β-cells. The lipotoxic effects of palmitic acid on INS-1 cells were measured, and JunD small-interfering RNA was used to assess the effect of JunD in regulating lipid metabolism and insulin secretion. The results showed that palmitic acid stimulation induced the overexpression of JunD, impaired glucose-stimulated insulin secretion, and increased intracellular lipid accumulation of β-cells. Moreover, the gene expression involved in lipid metabolism (Scd1, Fabp4, Fas, Cd36, Lpl, and Plin5) was upregulated, while gene expression involved in the pancreatic β-cells function (such as Pdx1, Nkx6.1, Glut2, and Irs-2) was decreased. Gene silencing of JunD reversed the lipotoxic effects induced by PA on β-cells. These results suggested that JunD regulated the function of pancreatic β-cells by altering lipid accumulation.
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Affiliation(s)
- Kexin Wang
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, China
| | - Yixin Cui
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong University, Jinan, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, China
| | - Peng Lin
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong University, Jinan, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, China
| | - Zhina Yao
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China
- *Correspondence: Zhina Yao, ; Yu Sun,
| | - Yu Sun
- Department of Endocrinology, Qilu Hospital of Shandong University, Shandong University, Jinan, China
- Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, China
- *Correspondence: Zhina Yao, ; Yu Sun,
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