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Jiang H, Zang L. GLP-1/GLP-1RAs: New Options for the Drug Treatment of NAFLD. Curr Pharm Des 2024; 30:100-114. [PMID: 38532322 DOI: 10.2174/0113816128283153231226103218] [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: 10/12/2023] [Accepted: 12/14/2023] [Indexed: 03/28/2024]
Abstract
Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a global public health concern. Currently, the cornerstone of NAFLD treatment is lifestyle modification and, if necessary, weight loss. However, compliance is a challenge, and this approach alone may not be sufficient to halt and treat the more serious disease development, so medication is urgently needed. Nevertheless, no medicines are approved to treat NAFLD. Glucagon-like peptide-1 (GLP-1) is an enteropeptide hormone that inhibits glucagon synthesis, promotes insulin secretion, and delays gastric emptying. GLP-1 has been found in recent studies to be beneficial for the management of NAFLD, and the marketed GLP-1 agonist drugs have different degrees of effectiveness for NAFLD while lowering blood glucose. In this article, we review GLP-1 and its physiological roles, the pathogenesis of NAFLD, the correlation between NAFLD and GLP-1 signaling, and potential strategies for GLP-1 treatment of NAFLD.
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Affiliation(s)
- Haoran Jiang
- Laboratory of Pharmacology, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Linquan Zang
- Laboratory of Pharmacology, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
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2
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Xu Q, Zhang X, Li T, Shao S. Exenatide regulates Th17/Treg balance via PI3K/Akt/FoxO1 pathway in db/db mice. Mol Med 2022; 28:144. [PMID: 36463128 PMCID: PMC9719171 DOI: 10.1186/s10020-022-00574-6] [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: 07/04/2022] [Accepted: 11/11/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The T helper 17 (Th17)/T regulatory (Treg) cell imbalance is involved in the course of obesity and type 2 diabetes mellitus (T2DM). In the current study, the exact role of glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide on regulating the Th17/Treg balance and the underlying molecular mechanisms are investigated in obese diabetic mice model. METHODS Metabolic parameters were monitored in db/db mice treated with/without exenatide during 8-week study period. The frequencies of Th17 and Treg cells from peripheral blood and pancreas in db/db mice were assessed. The phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/Forkhead box O1 (FoxO1) pathway in Th17 and Treg cells from the spleens of male C57BL/6J mice was detected by western blotting. In addition, the expression of glucagon-like peptide-1 receptor (GLP-1R) in peripheral blood mononuclear cells (PBMCs) of male C57BL/6J mice was analyzed. RESULTS Exenatide treatment improved β-cell function and insulitis in addition to glucose, insulin sensitivity and weight. Increased Th17 and decreased Treg cells in peripheral blood were present as diabetes progressed while exenatide corrected this imbalance. Progressive IL-17 + T cell infiltration of pancreatic islets was alleviated by exenatide intervention. In vitro study showed no significant difference in the level of GLP-1R expression in PBMCs between control and palmitate (PA) groups. In addition, PA could promote Th17 but suppress Treg differentiation along with down-regulating the phosphorylation of PI3K/Akt/FoxO1, which was reversed by exenatide intervention. FoxO1 inhibitor AS1842856 could abrogate all these effects of exenatide against lipid stress. CONCLUSIONS Exenatide could restore systemic Th17/Treg balance via regulating FoxO1 pathway with the progression of diabetes in db/db mice. The protection of pancreatic β-cell function may be partially mediated by inhibiting Th17 cell infiltration into pancreatic islets, and the resultant alleviation of islet inflammation.
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Affiliation(s)
- Qinqin Xu
- grid.33199.310000 0004 0368 7223Division of Endocrinology, Tongji Hospital, Huazhong University of Science and Technology, Jiefang Road 1095, Wuhan, 430030 Hubei Province People’s Republic of China ,Branch of National Clinical Research Center for Metabolic Diseases, Hubei, People’s Republic of China
| | - Xiaoling Zhang
- grid.33199.310000 0004 0368 7223Division of Endocrinology, Tongji Hospital, Huazhong University of Science and Technology, Jiefang Road 1095, Wuhan, 430030 Hubei Province People’s Republic of China ,Branch of National Clinical Research Center for Metabolic Diseases, Hubei, People’s Republic of China
| | - Tao Li
- grid.33199.310000 0004 0368 7223Division of Ophthalmology, Tongji Hospital, Huazhong University of Science and Technology, Jiefang Road 1095, Wuhan, 430030 Hubei Province People’s Republic of China
| | - Shiying Shao
- grid.33199.310000 0004 0368 7223Division of Endocrinology, Tongji Hospital, Huazhong University of Science and Technology, Jiefang Road 1095, Wuhan, 430030 Hubei Province People’s Republic of China ,Branch of National Clinical Research Center for Metabolic Diseases, Hubei, People’s Republic of China
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Li X, Zhang Y, He F, Gao D, Che B, Cao X, Huang S, Zheng M, Han H. miR-582 Suppresses the Proliferation of B-Cell Precursor Acute Lymphoblastic Leukemia (BCP-ALL) Cells and Protects Them From Natural Killer Cell-Mediated Cytotoxicity. Front Immunol 2022; 13:853094. [PMID: 35514986 PMCID: PMC9065596 DOI: 10.3389/fimmu.2022.853094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/16/2022] [Indexed: 12/02/2022] Open
Abstract
B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a malignancy characterized by the aberrant accumulation of immature B-cell precursors in bone marrow and other lymphoid organs. Although several intrinsic regulatory signals participating in BCP-ALL have been clarified, detailed intrinsic and extrinsic mechanisms that regulate BCP-ALL progression have not been fully understood. In the current study, we report that miR-582 is downregulated in BCP-ALL cells compared with normal B cells. Forced overexpression of miR-582 attenuated BCP-ALL cell proliferation and survival. We found that miR-582 overexpression disturbed the mitochondrial metabolism of BCP-ALL cells, leading to less ATP but more ROS production. Mechanistically, we identified PPTC7 as a direct target of miR-582. MiR-582 overexpression inhibited the activity of CoQ10, which is downstream of PPTC7 and played an important positive regulatory role in mitochondrial electron transportation. Finally, we found that overexpression of miR-582 upregulated the expression of immune checkpoint molecule CD276 and reduced NK cell-mediated cytotoxicity against BCP-ALL cells. CD276 blockade significantly increased NK cell-mediated cytotoxicity against miR-582-overexpressing BCP-ALL cells. Together, our research demonstrates that miR-582 acts as a negative regulator of BCP-ALL cells by reducing proliferation and survival, but protects BCP-ALL cells from NK cell-mediated cytotoxicity, suggesting that miR-582 may be a new therapeutic biomarker for BCP-ALL with CD276 blocker.
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Affiliation(s)
- Xinxin Li
- Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, Xi'an, China.,Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen, China
| | - Yufei Zhang
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, China
| | - Fei He
- Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Dan Gao
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, China
| | - Bo Che
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, China
| | - Xiuli Cao
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Siyong Huang
- Department of Hematology, Xi'an International Medical Center Hospital, Xi'an, China
| | - Minhua Zheng
- Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, Xi'an, China
| | - Hua Han
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an, China
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Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies. Int J Mol Sci 2021; 22:ijms22105303. [PMID: 34069914 PMCID: PMC8157542 DOI: 10.3390/ijms22105303] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.
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Šrámek J, Němcová-Fürstová V, Kovář J. Molecular Mechanisms of Apoptosis Induction and Its Regulation by Fatty Acids in Pancreatic β-Cells. Int J Mol Sci 2021; 22:4285. [PMID: 33924206 PMCID: PMC8074590 DOI: 10.3390/ijms22084285] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/09/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cell failure and death contribute significantly to the pathogenesis of type 2 diabetes. One of the main factors responsible for β-cell dysfunction and subsequent cell death is chronic exposure to increased concentrations of FAs (fatty acids). The effect of FAs seems to depend particularly on the degree of their saturation. Saturated FAs induce apoptosis in pancreatic β-cells, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction by saturated FAs in β-cells are not completely elucidated. Saturated FAs induce ER stress, which in turn leads to activation of all ER stress pathways. When ER stress is severe or prolonged, apoptosis is induced. The main mediator seems to be the CHOP transcription factor. Via regulation of expression/activity of pro- and anti-apoptotic Bcl-2 family members, and potentially also through the increase in ROS production, CHOP switches on the mitochondrial pathway of apoptosis induction. ER stress signalling also possibly leads to autophagy signalling, which may activate caspase-8. Saturated FAs activate or inhibit various signalling pathways, i.e., p38 MAPK signalling, ERK signalling, ceramide signalling, Akt signalling and PKCδ signalling. This may lead to the activation of the mitochondrial pathway of apoptosis, as well. Particularly, the inhibition of the pro-survival Akt signalling seems to play an important role. This inhibition may be mediated by multiple pathways (e.g., ER stress signalling, PKCδ and ceramide) and could also consequence in autophagy signalling. Experimental evidence indicates the involvement of certain miRNAs in mechanisms of FA-induced β-cell apoptosis, as well. In the rather rare situations when unsaturated FAs are also shown to be pro-apoptotic, the mechanisms mediating this effect in β-cells seem to be the same as for saturated FAs. To conclude, FA-induced apoptosis rather appears to be preceded by complex cross talks of multiple signalling pathways. Some of these pathways may be regulated by decreased membrane fluidity due to saturated FA incorporation. Few data are available concerning molecular mechanisms mediating the protective effect of unsaturated FAs on the effect of saturated FAs. It seems that the main possible mechanism represents a rather inhibitory intervention into saturated FA-induced pro-apoptotic signalling than activation of some pro-survival signalling pathway(s) or metabolic interference in β-cells. This inhibitory intervention may be due to an increase of membrane fluidity.
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Affiliation(s)
- Jan Šrámek
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
| | - Vlasta Němcová-Fürstová
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
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Abstract
Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of evidence affirms support for novel regulation, by G proteins, of specific intracellular signaling events, including actin cytoskeletal remodeling, transport of insulin-containing granules to the plasma membrane for fusion, and secretion of insulin into the circulation. This article highlights the following aspects of GPCR-G protein biology of the islet. First, it overviews our current understanding of the identity of a wide variety of G protein regulators and their modulatory roles in GPCR-G protein-effector coupling, which is requisite for optimal β-cell function under physiological conditions. Second, it describes evidence in support of novel, noncanonical, GPCR-independent mechanisms of activation of G proteins in the islet. Third, it highlights the evidence indicating that abnormalities in G protein function lead to islet β-cell dysregulation and demise under the duress of metabolic stress and diabetes. Fourth, it summarizes observations of potential beneficial effects of GPCR agonists in preventing/halting metabolic defects in the islet β-cell under various pathological conditions (e.g., metabolic stress and inflammation). Lastly, it identifies knowledge gaps and potential avenues for future research in this evolving field of translational islet biology. Published 2020. Compr Physiol 10:453-490, 2020.
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Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Center for Translational Research in Diabetes, Biomedical Research Service, John D. Dingell VA Medical Center, Wayne State University, Detroit, Michigan, USA
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Shen X, Luo L, Yang M, Lin Y, Li J, Yang L. Exendin‑4 inhibits lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of TLR4/NF‑κB signaling pathway. Int J Mol Med 2020; 45:1237-1249. [PMID: 32124969 DOI: 10.3892/ijmm.2020.4490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 12/02/2019] [Indexed: 11/05/2022] Open
Abstract
The present study aimed to investigate the relationship between the protective effects of exendin‑4 (EX‑4) on lipotoxicity‑induced oxidative stress and meta‑inflammation in β‑cells and the toll‑like receptor 4 (TLR4)/NF‑κB signaling pathway. Lipotoxicity, hydrogen peroxide (H2O2)‑induced oxidative stress in β cells, obese Sprague Dawley rats and TLR4 truncation rats were utilized in the present study. The expression levels were detected by western blotting; cell apoptosis was detected by TUNEL assay; and the intracellular reactive oxygen species (ROS) levels were analyzed using a ROS assay kit. The findings of the present study showed that EX‑4 inhibited the expression of TLR4, NF‑κB p65 subunit and p47phox in a concentration‑dependent manner, and decreased the intracellular level of ROS. Additionally, silencing of TLR4 expression enhanced the protective effects of EX‑4, while overexpression of TLR4 attenuated these protective influences. Simultaneously, it was demonstrated that TLR4 was involved in the process of EX‑4 intervention to inhibit H2O2‑induced oxidative stress in islet β‑cells. Moreover, it was found that EX‑4 also inhibited TLR4‑ or NF‑κB agonist‑induced oxidative stress. These results were also confirmed in an animal model of obese rats, in which EX‑4 was able to improve the function of β‑cells, attenuate oxidative stress, and inhibit the expression levels of TLR4 and NF‑κB p65 subunit in the pancreas of the diet‑induced obese rats. Furthermore, truncation of the TLR4 gene in SD rats delayed the aforementioned damage. In summary, EX‑4 may inhibit lipotoxicity‑induced oxidative stress in β‑cells by inhibiting the activation of the TLR4/NF‑κB signaling pathway.
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Affiliation(s)
- Ximei Shen
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Liufen Luo
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Meng Yang
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Yuxi Lin
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Jing Li
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Liyong Yang
- Endocrinology Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
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FMK, an Inhibitor of p90RSK, Inhibits High Glucose-Induced TXNIP Expression via Regulation of ChREBP in Pancreatic β Cells. Int J Mol Sci 2019; 20:ijms20184424. [PMID: 31505737 PMCID: PMC6770409 DOI: 10.3390/ijms20184424] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 12/24/2022] Open
Abstract
Hyperglycemia is the major characteristic of diabetes mellitus, and a chronically high glucose (HG) level causes β-cell glucolipotoxicity, which is characterized by lipid accumulation, impaired β-cell function, and apoptosis. TXNIP (Thioredoxin-interacting protein) is a key mediator of diabetic β-cell apoptosis and dysfunction in diabetes, and thus, its regulation represents a therapeutic target. Recent studies have reported that p90RSK is implicated in the pathogenesis of diabetic cardiomyopathy and nephropathy. In this study, we used FMK (a p90RSK inhibitor) to determine whether inhibition of p90RSK protects β-cells from chronic HG-induced TXNIP expression and to investigate the molecular mechanisms underlying the effect of FMK on its expression. In INS-1 pancreatic β-cells, HG-induced β-cell dysfunction, apoptosis, and ROS generation were significantly diminished by FMK. In contrast BI-D1870 (another p90RSK inhibitor) did not attenuate HG-induced TXNIP promoter activity or TXNIP expression. In addition, HG-induced nuclear translocation of ChREBP and its transcriptional target molecules were found to be regulated by FMK. These results demonstrate that HG-induced pancreatic β-cell dysfunction resulting in HG conditions is associated with TXNIP expression, and that FMK is responsible for HG-stimulated TXNIP gene expression by inactivating the regulation of ChREBP in pancreatic β-cells. Taken together, these findings suggest FMK may protect against HG-induced β-cell dysfunction and TXNIP expression by ChREBP regulation in pancreatic β-cells, and that FMK is a potential therapeutic reagent for the drug development of diabetes and its complications.
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Son S, Park EJ, Kim Y, Lee KC, Na DH. Chemical chaperone-conjugated exendin-4 as a cytoprotective agent for pancreatic β-cells. Int J Biochem Cell Biol 2018; 105:13-19. [DOI: 10.1016/j.biocel.2018.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/24/2018] [Accepted: 09/26/2018] [Indexed: 12/27/2022]
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Danilova T, Lindahl M. Emerging Roles for Mesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) in Pancreatic Beta Cells and Diabetes. Front Physiol 2018; 9:1457. [PMID: 30386256 PMCID: PMC6198132 DOI: 10.3389/fphys.2018.01457] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/26/2018] [Indexed: 12/31/2022] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) was originally identified as a secreted trophic factor for dopamine neurons in vitro. It protects and restores damaged cells in rodent models of Parkinson's disease, brain and heart ischemia, spinocerebellar ataxia and retina in vivo. However, its exact mechanism of action is not known. MANF is widely expressed in most human and mouse organs with high levels in secretory tissues. Intracellularly, MANF localizes to the endoplasmic reticulum (ER) and ER stress increases it's expression in cells and tissues. Furthermore, increased MANF levels has been detected in the sera of young children with newly diagnosed Type 1 (T1D) diabetes and Type 2 (T2D) diabetic patients. ER stress is caused by the accumulation of misfolded and aggregated proteins in the ER. It activates a cellular defense mechanism, the unfolded protein response (UPR), a signaling cascade trying to restore ER homeostasis. However, if prolonged, unresolved ER stress leads to apoptosis. Unresolved ER stress contributes to the progressive death of pancreatic insulin-producing beta cells in both T1D and T2D. Diabetes mellitus is characterized by hyperglycemia, caused by the inability of the beta cells to maintain sufficient levels of circulating insulin. The current medications, insulin and antidiabetic drugs, alleviate diabetic symptoms but cannot reconstitute physiological insulin secretion which increases the risk of devastating vascular complications of the disease. Thus, one of the main strategies in improving current diabetes therapy is to define and validate novel approaches to protect beta cells from stress as well as activate their regeneration. Embryonic deletion of the Manf gene in mice led to gradual postnatal development of insulin-deficient diabetes caused by reduced beta cell proliferation and increased beta cell death due to increased and sustained ER stress. In vitro, recombinant MANF partly protected mouse and human beta cells from ER stress-induced beta cell death and potentiated mouse and human beta cell proliferation. Importantly, in vivo overexpression of MANF in the pancreas of T1D mice led to increased beta cell proliferation and decreased beta cell death, suggesting that MANF could be a new therapeutic candidate for beta cell protection and regeneration in diabetes.
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Affiliation(s)
- Tatiana Danilova
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Maria Lindahl
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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Wei X, Zhu D, Feng C, Chen G, Mao X, Wang Q, Wang J, Liu C. Inhibition of peptidyl-prolyl cis-trans isomerase B mediates cyclosporin A-induced apoptosis of islet β cells. Exp Ther Med 2018; 16:3959-3964. [PMID: 30344674 PMCID: PMC6176207 DOI: 10.3892/etm.2018.6706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 08/29/2018] [Indexed: 12/21/2022] Open
Abstract
Cyclosporin A (CsA) is widely used as an immunosuppressor in the context of organ transplantation or autoimmune disorders. Recent studies have revealed the detrimental effects of CsA on insulin resistance and pancreatic β cell failure; however, the molecular mechanisms are unknown. The present study sought to confirm the associations between CsA and β cell failure, and to investigate the roles of proinsulin folding and endoplasmic reticulum (ER) stress in CsA-induced β cell failure. The viability of MIN6 cells treated with CsA was evaluated with MTT assay. Expression levels of insulin, peptidyl-prolyl cis-trans isomerase B (PPIB), cleaved caspase-3, phospho-protein kinase R (PKR)-like endoplasmic reticulum kinase (p-PERK), PKR-like endoplasmic reticulum kinase (PERK), binding immunoglobulin protein (BIP), and C/EBP homologous protein (CHOP) were detected via reducing western blot assay. Non-reducing western blot analysis was performed to examine the expression of misfolded proinsulin peptides. The proliferation of MIN6 cells was not inhibited by CsA at concentrations <1 µmol/l. CsA treatment resulted in the decreased expression of insulin and PPIB; however, it also increased the phosphorylation of PERK, and upregulated the expression of PERK, BIP, CHOP and cleaved caspase-3. The results indicated that CsA could induce pancreatic β cell dysfunction and the potential mechanism underlying this phenomenon may be PPIB-associated proinsulin misfolding, which in turn induces ER stress in β cells.
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Affiliation(s)
- Xiao Wei
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
| | - Dan Zhu
- Department of Endocrinology, Jiangdu People's Hospital of Yangzhou, Yangzhou, Jiangsu 225200, P.R. China
| | - Chenchen Feng
- Central Laboratory, Jiangsu Province Blood Center, Nanjing, Jiangsu 210042, P.R. China
| | - Guofang Chen
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
| | - Xiaodong Mao
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
| | - Qifeng Wang
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
| | - Jie Wang
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
| | - Chao Liu
- Department of Endocrinology, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210028, P.R. China
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Cnop M, Toivonen S, Igoillo-Esteve M, Salpea P. Endoplasmic reticulum stress and eIF2α phosphorylation: The Achilles heel of pancreatic β cells. Mol Metab 2017; 6:1024-1039. [PMID: 28951826 PMCID: PMC5605732 DOI: 10.1016/j.molmet.2017.06.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pancreatic β cell dysfunction and death are central in the pathogenesis of most if not all forms of diabetes. Understanding the molecular mechanisms underlying β cell failure is important to develop β cell protective approaches. SCOPE OF REVIEW Here we review the role of endoplasmic reticulum stress and dysregulated endoplasmic reticulum stress signaling in β cell failure in monogenic and polygenic forms of diabetes. There is substantial evidence for the presence of endoplasmic reticulum stress in β cells in type 1 and type 2 diabetes. Direct evidence for the importance of this stress response is provided by an increasing number of monogenic forms of diabetes. In particular, mutations in the PERK branch of the unfolded protein response provide insight into its importance for human β cell function and survival. The knowledge gained from different rodent models is reviewed. More disease- and patient-relevant models, using human induced pluripotent stem cells differentiated into β cells, will further advance our understanding of pathogenic mechanisms. Finally, we review the therapeutic modulation of endoplasmic reticulum stress and signaling in β cells. MAJOR CONCLUSIONS Pancreatic β cells are sensitive to excessive endoplasmic reticulum stress and dysregulated eIF2α phosphorylation, as indicated by transcriptome data, monogenic forms of diabetes and pharmacological studies. This should be taken into consideration when devising new therapeutic approaches for diabetes.
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Key Words
- ATF, activating transcription factor
- CHOP, C/EBP homologous protein
- CRISPR, clustered regularly interspaced short palindromic repeats
- CReP, constitutive repressor of eIF2α phosphorylation
- Diabetes
- ER, endoplasmic reticulum
- ERAD, ER-associated degradation
- Endoplasmic reticulum stress
- GCN2, general control non-derepressible-2
- GIP, glucose-dependent insulinotropic polypeptide
- GLP-1, glucagon-like peptide 1
- GWAS, genome-wide association study
- HNF1A, hepatocyte nuclear factor 1-α
- HRI, heme-regulated inhibitor kinase
- IAPP, islet amyloid polypeptide
- IER3IP1, immediate early response-3 interacting protein-1
- IRE1, inositol-requiring protein-1
- ISR, integrated stress response
- Insulin
- Islet
- MEHMO, mental retardation, epilepsy, hypogonadism and -genitalism, microcephaly and obesity
- MODY, maturity-onset diabetes of the young
- NRF2, nuclear factor, erythroid 2 like 2
- PBA, 4-phenyl butyric acid
- PERK, PKR-like ER kinase
- PKR, protein kinase RNA
- PP1, protein phosphatase 1
- PPA, phenylpropenoic acid glucoside
- Pancreatic β cell
- Pdx1, pancreatic duodenal homeobox 1
- RIDD, regulated IRE1-dependent decay
- RyR2, type 2 ryanodine receptor/Ca2+ release channel
- SERCA, sarcoendoplasmic reticulum Ca2+ ATPase
- TUDCA, taurine-conjugated ursodeoxycholic acid derivative
- UPR, unfolded protein response
- WFS, Wolfram syndrome
- XBP1, X-box binding protein 1
- eIF2, eukaryotic translation initiation factor 2
- eIF2α
- hESC, human embryonic stem cell
- hPSC, human pluripotent stem cell
- hiPSC, human induced pluripotent stem cell
- uORF, upstream open reading frame
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Affiliation(s)
- Miriam Cnop
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Sanna Toivonen
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Paraskevi Salpea
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
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13
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Bin Feng, Meng R, Bin Huang, Bi Y, Shen S, Zhu D. Silymarin protects against renal injury through normalization of lipid metabolism and mitochondrial biogenesis in high fat-fed mice. Free Radic Biol Med 2017. [PMID: 28625483 DOI: 10.1016/j.freeradbiomed.2017.06.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Obesity is associated with an increased risk of chronic kidney diseases and the conventional treatment with renin-angiotensin-aldosterone system (RAAS) inhibitors is not enough to prevent renal injury and prolong the progression of disease. Recently, silymarin has shown protective effects on renal tissue injury, but the underlying mechanisms remain elusive. The goal of this study was to investigate the potential capacity of silymarin to prevent renal injury during obesity induced by high fat diet (HFD) in mice. In vivo, male C57BL/6 mice received HFD (60% of total calories) for 12 weeks, randomized and treated orally with vehicle saline or silymarin (30mg/kg body weight/d) for 4 weeks. In vitro, human proximal tubular epithelial cells (HK2) were exposed to 300μM palmitic acid (PA) for 36h followed by silymarin administration at different concentrations. The administration of silymarin significantly ameliorated HFD induced glucose metabolic disorders, oxidative stress and pathological alterations in the kidney. Silymarin significantly mitigated renal lipid accumulation, fatty acid β-oxidation and mitochondrial biogenesis in HFD mice and PA treated HK2 cells. Furthermore, silymarin partly restored mitochondrial membrane potential of HK2 cells after PA exposure. In conclusion, silymarin can improve oxidative stress and preserve mitochondrial dysfunction in the kidney, potentially via preventing accumulation of renal lipids and fatty acid β-oxidation.
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MESH Headings
- Animals
- Antioxidants/pharmacology
- Cell Line
- Diet, High-Fat/adverse effects
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Epithelial Cells/pathology
- Humans
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Lipid Metabolism/drug effects
- Male
- Membrane Potential, Mitochondrial/drug effects
- Mice
- Mice, Inbred C57BL
- Mitochondria/drug effects
- Mitochondria/metabolism
- Obesity/diet therapy
- Obesity/etiology
- Obesity/metabolism
- Obesity/pathology
- Oxidation-Reduction
- Oxidative Stress/drug effects
- Palmitic Acid/antagonists & inhibitors
- Palmitic Acid/pharmacology
- Protective Agents/pharmacology
- Renal Insufficiency, Chronic/diet therapy
- Renal Insufficiency, Chronic/etiology
- Renal Insufficiency, Chronic/metabolism
- Renal Insufficiency, Chronic/pathology
- Silymarin/pharmacology
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Affiliation(s)
- Bin Feng
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China; Department of Endocrinology, The First Affiliated Hospital of Soochow University, 188 Shizi Road, Suzhou, Jiangsu 215006, China
| | - Ran Meng
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China
| | - Bin Huang
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China
| | - Yan Bi
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China
| | - Shanmei Shen
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China
| | - Dalong Zhu
- Department of Endocrinology, Nanjing Drum Tower Hospital, Nanjing University School of Medicine, 321 Zhongshan Road, Nanjing, Jiangsu 210008, China.
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14
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An oasis in the desert of cancer chemotherapeutic resistance: The enlightenment from reciprocal crosstalk between signaling pathways of UPR and autophagy in cancers. Biomed Pharmacother 2017; 92:972-981. [DOI: 10.1016/j.biopha.2017.05.132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/28/2017] [Accepted: 05/28/2017] [Indexed: 12/21/2022] Open
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15
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Oh YS, Seo E, Park K, Jun HS. Compound 19e, a Novel Glucokinase Activator, Protects against Cytokine-Induced Beta-Cell Apoptosis in INS-1 Cells. Front Pharmacol 2017; 8:169. [PMID: 28405188 PMCID: PMC5370240 DOI: 10.3389/fphar.2017.00169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/14/2017] [Indexed: 01/28/2023] Open
Abstract
Previously, compound 19e, a novel heteroaryl-containing benzamide derivative, was identified as a potent glucokinase activator (GKA) and showed a glucose-lowering effect in diabetic mice. In this study, the anti-apoptotic actions of 19e were evaluated in INS-1 pancreatic beta-cells co-treated with TNF-α and IL-1β to induce cell death. Compound 19e protected INS-1 cells from cytokine-induced cell death, and the effect was similar to treatment with another GKA or exendin-4. Compound 19e reduced annexin-V stained cells and the expression of cleaved caspase-3 and poly (ADP-ribose) polymerase protein, as well as upregulated the expression of B-cell lymphoma-2 protein. Compound 19e inhibited apoptotic signaling via induction of the ATP content, and the effect was correlated with the downregulation of nuclear factor-κB p65 and inducible nitric oxide synthase. Further, 19e increased NAD-dependent protein deacetylase sirtuin-1 (SIRT1) deacetylase activity, and the anti-apoptotic effect of 19e was attenuated by SIRT1 inhibitor or SIRT1 siRNA treatment. Our results demonstrate that the novel GKA, 19e, prevents cytokine-induced beta-cell apoptosis via SIRT1 activation and has potential as a therapeutic drug for the preservation of pancreatic beta-cells.
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Affiliation(s)
- Yoon Sin Oh
- College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon UniversityIncheon, South Korea; Gachon Medical Research Institute, Gil HospitalIncheon, South Korea; Department of Food and Nutrition, Eulji UniversitySeongnam, South Korea
| | - Eunhui Seo
- College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University Incheon, South Korea
| | - Kaapjoo Park
- Yuhan Research Institute Gyeonggi-do, South Korea
| | - Hee-Sook Jun
- College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon UniversityIncheon, South Korea; Gachon Medical Research Institute, Gil HospitalIncheon, South Korea; College of Pharmacy and Gachon Institute of Pharmaceutical Science, Gachon UniversityIncheon, South Korea
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16
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Sarvani C, Sireesh D, Ramkumar KM. Unraveling the role of ER stress inhibitors in the context of metabolic diseases. Pharmacol Res 2017; 119:412-421. [PMID: 28237513 DOI: 10.1016/j.phrs.2017.02.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/16/2017] [Accepted: 02/20/2017] [Indexed: 02/05/2023]
Abstract
ER stress is provoked by the accumulation of unfolded and misfolded proteins in the ER lumen leading to perturbations in ER homeostasis. ER stress activates a signaling cascade called the Unfolded Protein Response (UPR) which triggers a set of transcriptional and translational events that restore ER homeostasis, promoting cell survival and adaptation. If this adaptive response fails, a terminal UPR program commits such cells to apoptosis. Existing preclinical and clinical evidence testify that prolonged ER stress escalates the risk of several metabolic disorders including diabetes, obesity and dyslipidemia. There have been considerable efforts to develop small molecules that are capable of ameliorating ER stress. Few naturally occurring and synthetic molecules have already been demonstrated for their efficacy in abrogating ER stress in both in vitro and in vivo models of metabolic disorders. This review provides a broad overview of the molecular mechanisms of inhibition of ER stress and its association with various metabolic diseases.
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Affiliation(s)
- Chodisetty Sarvani
- SRM Research Institute, SRM University, Kattankulathur 603 203, Tamilnadu, India
| | - Dornadula Sireesh
- SRM Research Institute, SRM University, Kattankulathur 603 203, Tamilnadu, India
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17
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Kinase Signaling in Apoptosis Induced by Saturated Fatty Acids in Pancreatic β-Cells. Int J Mol Sci 2016; 17:ijms17091400. [PMID: 27626409 PMCID: PMC5037680 DOI: 10.3390/ijms17091400] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell failure and death is considered to be one of the main factors responsible for type 2 diabetes. It is caused by, in addition to hyperglycemia, chronic exposure to increased concentrations of fatty acids, mainly saturated fatty acids. Molecular mechanisms of apoptosis induction by saturated fatty acids in β-cells are not completely clear. It has been proposed that kinase signaling could be involved, particularly, c-Jun N-terminal kinase (JNK), protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and Akt kinases and their pathways. In this review, we discuss these kinases and their signaling pathways with respect to their possible role in apoptosis induction by saturated fatty acids in pancreatic β-cells.
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18
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Meyerovich K, Ortis F, Allagnat F, Cardozo AK. Endoplasmic reticulum stress and the unfolded protein response in pancreatic islet inflammation. J Mol Endocrinol 2016; 57:R1-R17. [PMID: 27067637 DOI: 10.1530/jme-15-0306] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 04/11/2016] [Indexed: 12/13/2022]
Abstract
Insulin-secreting pancreatic β-cells are extremely dependent on their endoplasmic reticulum (ER) to cope with the oscillatory requirement of secreted insulin to maintain normoglycemia. Insulin translation and folding rely greatly on the unfolded protein response (UPR), an array of three main signaling pathways designed to maintain ER homeostasis and limit ER stress. However, prolonged or excessive UPR activation triggers alternative molecular pathways that can lead to β-cell dysfunction and apoptosis. An increasing number of studies suggest a role of these pro-apoptotic UPR pathways in the downfall of β-cells observed in diabetic patients. Particularly, the past few years highlighted a cross talk between the UPR and inflammation in the context of both type 1 (T1D) and type 2 diabetes (T2D). In this article, we describe the recent advances in research regarding the interplay between ER stress, the UPR, and inflammation in the context of β-cell apoptosis leading to diabetes.
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Affiliation(s)
- Kira Meyerovich
- ULB Center for Diabetes ResearchUniversité Libre de Bruxelles (ULB), Brussels, Belgium
| | - Fernanda Ortis
- Department of Cell and Developmental BiologyUniversidade de São Paulo, São Paulo, Brazil
| | - Florent Allagnat
- Department of Vascular SurgeryCentre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Alessandra K Cardozo
- ULB Center for Diabetes ResearchUniversité Libre de Bruxelles (ULB), Brussels, Belgium
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19
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Jung TW, Choi KM. Pharmacological Modulators of Endoplasmic Reticulum Stress in Metabolic Diseases. Int J Mol Sci 2016; 17:ijms17020192. [PMID: 26840310 PMCID: PMC4783926 DOI: 10.3390/ijms17020192] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 01/20/2016] [Accepted: 01/27/2016] [Indexed: 01/23/2023] Open
Abstract
The endoplasmic reticulum (ER) is the principal organelle responsible for correct protein folding, a step in protein synthesis that is critical for the functional conformation of proteins. ER stress is a primary feature of secretory cells and is involved in the pathogenesis of numerous human diseases, such as certain neurodegenerative and cardiometabolic disorders. The unfolded protein response (UPR) is a defense mechanism to attenuate ER stress and maintain the homeostasis of the organism. Two major degradation systems, including the proteasome and autophagy, are involved in this defense system. If ER stress overwhelms the capacity of the cell's defense mechanisms, apoptotic death may result. This review is focused on the various pharmacological modulators that can protect cells from damage induced by ER stress. The possible mechanisms for cytoprotection are also discussed.
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Affiliation(s)
- Tae Woo Jung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul 152-703, Korea.
| | - Kyung Mook Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul 152-703, Korea.
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20
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Wang J, Song MY, Bae UJ, Lim JM, Kwon KS, Park BH. n-3 Polyunsaturated fatty acids protect against pancreatic β-cell damage due to ER stress and prevent diabetes development. Mol Nutr Food Res 2015; 59:1791-802. [PMID: 26080997 DOI: 10.1002/mnfr.201500299] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/07/2015] [Accepted: 06/09/2015] [Indexed: 12/11/2022]
Abstract
SCOPE In this study, we focus on the effects of n-3 polyunsaturated fatty acids (PUFAs) on tunicamycin-, streptozotocin-, or high fat diet (HFD)-induced β-cell damage and dysfunction. MATERIALS AND METHODS Pretreatment with n-3 PUFAs protected RINm5F cells and mouse islets against tunicamycin-induced β-cell damage through suppression of ER stress and apoptosis induction. This protective effect of n-3 PUFAs on β-cells was further demonstrated by the normalization of insulin secretion in response to glucose in tunicamycin-treated islets. In multiple low-dose streptozotocin-induced diabetes models, fat-1 mice, which endogenously synthesize n-3 PUFAs from n-6 PUFAs, were fully resistant to the development of diabetes, with normal islet morphology, high insulin immunoreactivity, and decreased apoptotic cells. In HFD-induced diabetes models, fat-1 mice also exhibited improved glucose tolerance and functional β-cell mass. In both diabetes models, we observed an attenuation of ER stress in fat-1 mice. Interestingly, n-3 PUFAs attenuated the nuclear translocation of lipogenic transcription factors sterol regulatory element-binding protein-1 (SREBP-1) and C/EBPβ, induced by tunicamycin or HFD, suggesting that n-3 PUFAs suppress ER stress via modulation of SREBP-1 and C/EBPβ. CONCLUSION Together, these results suggest that n-3 PUFAs block ER stress, thus protecting β cells against diabetogenic insult; therefore, dietary supplementation of n-3 PUFAs has therapeutic potential for the preservation of functional β-cell mass.
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Affiliation(s)
- Jie Wang
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Mi-Young Song
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Ui-Jin Bae
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Jung Min Lim
- Department of Anatomy, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Keun Sang Kwon
- Department of Preventive Medicine, Chonbuk National University Medical School, Jeonju, Republic of Korea
| | - Byung-Hyun Park
- Department of Biochemistry, Chonbuk National University Medical School, Jeonju, Republic of Korea
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21
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Oh YS. Mechanistic insights into pancreatic beta-cell mass regulation by glucose and free fatty acids. Anat Cell Biol 2015; 48:16-24. [PMID: 25806118 PMCID: PMC4371177 DOI: 10.5115/acb.2015.48.1.16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 02/04/2015] [Indexed: 01/14/2023] Open
Abstract
Pancreatic islets are responsible for blood glucose homeostasis. Reduced numbers of functional (insulin-secreting) beta-cells in pancreatic islets underlies diabetes. Restoration of the secretion of the proper amount of insulin is a goal. Beta-cell mass is increased by neogenesis, proliferation and cell hypertrophy, and is decreased by beta-cell death primarily through apoptosis. Many hormones and nutrients affect beta-cell mass, and glucose and free fatty acid are thought to be the most important determinants of beta-cell equilibrium. A number of molecular pathways have been implicated in beta-cell mass regulation and have been studied. This review will focus on the role of the principle metabolites, glucose and free fatty acid, and the downstream signaling pathways regulating beta-cell mass by these metabolites.
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Affiliation(s)
- Yoon Sin Oh
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea. ; Gachon Medical Research Institute, Gil Hospital, Incheon, Korea
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22
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Lenin R, Mohan V, Balasubramanyam M. SEAP activity serves for demonstrating ER stress induction by glucolipotoxicity as well as testing ER stress inhibitory potential of therapeutic agents. Mol Cell Biochem 2015; 404:271-9. [DOI: 10.1007/s11010-015-2387-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/05/2015] [Indexed: 01/06/2023]
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Wu YJ, Guo X, Li CJ, Li DQ, Zhang J, Yang Y, Kong Y, Guo H, Liu DM, Chen LM. Dipeptidyl peptidase-4 inhibitor, vildagliptin, inhibits pancreatic beta cell apoptosis in association with its effects suppressing endoplasmic reticulum stress in db/db mice. Metabolism 2015; 64:226-35. [PMID: 25195070 DOI: 10.1016/j.metabol.2014.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/17/2014] [Accepted: 08/12/2014] [Indexed: 12/11/2022]
Abstract
AIMS Vildagliptin promotes beta cell survival by inhibiting cell apoptosis. It has been suggested that chronic ER (endoplasmic reticulum) stress triggers beta cell apoptosis. The objective of the study is to explore whether the pro-survival effect of vildagliptin is associated with attenuation of endoplasmic reticulum stress in islets of db/db mice. METHODS Vildagliptin was orally administered to db/db mice for 6 weeks, followed by evaluation of beta cell apoptosis by caspase3 activity and TUNEL staining method. Endoplasmic reticulum stress markers were determined with quantitative RT-PCR, immunohistochemistry and immunoblot analysis. RESULTS After 6 weeks of treatment, vildagliptin treatment increased plasma active GLP-1 levels (22.63±1.19 vs. 11.69±0.44, P<0.001), inhibited beta cell apoptosis as demonstrated by lower amounts of TUNEL staining nuclei (0.37±0.03 vs. 0.55±0.03, P<0.01) as well as decreased caspase3 activity (1.48±0.11 vs. 2.67±0.13, P<0.01) in islets of diabetic mice compared with untreated diabetic group. Further, vildagliptin treatment down-regulated several genes related to endoplasmic reticulum stress including TRIB3 (tribbles homolog 3) (15.9±0.4 vs. 33.3±1.7, ×10⁻³, P<0.001), ATF-4(activating transcription factor 4) (0.83±0.06 vs. 1.42±0.02, P<0.001) and CHOP(C/EBP homologous protein) (0.07±0.01 vs. 0.16±0.01, P<0.001). CONCLUSIONS Vildagliptin promoted beta cell survival in db/db mice in association with down-regulating markers of endoplasmic reticulum stress including TRIB3, ATF-4 as well as CHOP.
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Affiliation(s)
- Yan-ju Wu
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Xin Guo
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Chun-jun Li
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Dai-qing Li
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Jie Zhang
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Yiping Yang
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Yan Kong
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Hang Guo
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - De-min Liu
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Li-ming Chen
- Key Laboratory of Hormones and Development (Ministry of Health), Metabolic Diseases Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China.
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Goundan PN, Underwood P, Mantzoros CS. Incretin therapy and beta cell function. Metabolism 2015; 64:157-9. [PMID: 25456457 DOI: 10.1016/j.metabol.2014.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 10/07/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Poorani N Goundan
- Section of Endocrinology, Boston VA Healthcare System, 150S Huntington Ave, Jamaica Plain, MA 02130; Section of Endocrinology, Diabetes and Nutrition, Boston University Medical Center, 88 East Newton Street, Boston, MA 02118
| | - Patricia Underwood
- Section of Endocrinology, Boston VA Healthcare System, 150S Huntington Ave, Jamaica Plain, MA 02130
| | - Christos S Mantzoros
- Section of Endocrinology, Boston VA Healthcare System, 150S Huntington Ave, Jamaica Plain, MA 02130; Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215.
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Tseng CH, Lee KY, Tseng FH. An updated review on cancer risk associated with incretin mimetics and enhancers. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2015; 33:67-124. [PMID: 25803196 DOI: 10.1080/10590501.2015.1003496] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Incretin-based therapies, including the use of incretin mimetics of glucagon-like peptide-1 receptor (GLP-1R) agonists and incretin enhancers of dipeptidyl-peptidase 4 (DPP-4) inhibitors, are widely used by clinicians for glucose lowering in patients with type 2 diabetes mellitus. These agents have benefits of a lower risk of hypoglycemia, being neutral for body weight for DPP-4 inhibitors and having a potential for weight reduction with GLP-1R agonists. They may also have a neutral or beneficial cardiovascular effect. Despite these benefits, an increased risk of cancer (especially pancreatic cancer and thyroid cancer) associated with incretin-based therapies has been reported. In this article, we reviewed related literature of experimental animal and observational human studies, clinical trials, and meta-analyses published until December 15, 2014. Current studies suggested a probable role of GLP-1R activation on the development of pancreatic cancer and thyroid cancer in rodents, but such an effect in humans is not remarkable due to the lower or lack of expression of GLP-1R on human pancreatic ductal cells and thyroid tissues. Findings in human studies are controversial and inconclusive. In the analyses of the US Food and Drug Administration adverse events reporting system, a significantly higher risk of pancreatic cancer was observed for GLP-1R agonists and DPP-4 inhibitors, but a significantly higher risk of thyroid cancer was only observed for GLP-1R agonists. Such a higher risk of pancreatic cancer or thyroid cancer could not be similarly demonstrated in other human observational studies or analyses of data from clinical trials. With regards to cancers other than pancreatic cancer and thyroid cancer, available studies supported a neutral association in humans. Some preliminary studies even suggested a potentially beneficial effect on the development of other cancers with the use of incretins. Based on current evidence, continuous monitoring of the cancer issues related to incretin-based therapies is required, even though the benefits may outweigh the potential cancer risk in the general patients with type 2 diabetes mellitus.
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Affiliation(s)
- Chin-Hsiao Tseng
- a Department of Internal Medicine , National Taiwan University Hospital , Taipei , Taiwan
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26
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Bouchard-Mercier A, Rudkowska I, Lemieux S, Couture P, Pérusse L, Vohl MC. SREBF1 gene variations modulate insulin sensitivity in response to a fish oil supplementation. Lipids Health Dis 2014; 13:152. [PMID: 25270430 PMCID: PMC4196000 DOI: 10.1186/1476-511x-13-152] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/27/2014] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND An important inter-individual variability in the response of insulin sensitivity following a fish oil supplementation has been observed. The objective was to examine the associations between single nucleotide polymorphisms (SNPs) within sterol regulatory element binding transcription factor 1 (SREBF1) gene and the response of insulin sensitivity to a fish oil supplementation. METHODS Participants (n = 210) were recruited in the greater Quebec City area and followed a 6-week fish oil supplementation protocol (5 g/day: 1.9-2.2 g EPA; 1.1 g DHA). Insulin sensitivity was assessed by the quantitative insulin sensitivity check index (QUICKI). Three tag SNPs (tSNPs) within SREBF1 gene were genotyped according to TAQMAN methodology. RESULTS Three tSNPs (rs12953299, rs4925118 and rs4925115) covered 100% of the known genetic variability within SREBF1 gene. None of the three tSNPs was associated with either baseline fasting insulin concentrations (rs12953299, rs4925118 and rs4925115) (p = 0.29, p = 0.20 and p = 0.70, respectively) or QUICKI (p = 0.20, p = 0.18 and p = 0.76, respectively). The three tSNPs (rs12953299, rs4925118 and rs4925115) were associated with differences in the response of plasma insulin levels (p = 0.01, p = 0.005 and p = 0.004, respectively) and rs12953299 as well as rs4925115 were associated with the insulin sensitivity response (p = 0.009 and p = 0.01, respectively) to the fish oil supplementation, independently of the effects of age, sex and BMI. CONCLUSIONS The genetic variability within SREBF1 gene has an impact on the insulin sensitivity in response to a fish oil supplementation. TRIAL REGISTRATION clinicaltrials.gov: NCT01343342.
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Affiliation(s)
| | | | | | | | | | - Marie-Claude Vohl
- Institute of Nutrition and Functional Foods (INAF), Laval University, 2440 Hochelaga Blvd,, Quebec G1V 0A6, Canada.
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Wang M, Kaufman RJ. The impact of the endoplasmic reticulum protein-folding environment on cancer development. Nat Rev Cancer 2014; 14:581-97. [PMID: 25145482 DOI: 10.1038/nrc3800] [Citation(s) in RCA: 776] [Impact Index Per Article: 77.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The endoplasmic reticulum (ER) is an essential organelle in eukaryotic cells for the storage and regulated release of calcium and as the entrance to the secretory pathway. Protein misfolding in the ER causes accumulation of misfolded proteins (ER stress) and activation of the unfolded protein response (UPR), which has evolved to maintain a productive ER protein-folding environment. Both ER stress and UPR activation are documented in many different human cancers. In this Review, we summarize the impact of ER stress and UPR activation on every aspect of cancer and discuss outstanding questions for which answers will pave the way for therapeutics.
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Affiliation(s)
- Miao Wang
- Degenerative Diseases Program, Center for Cancer Research, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Rd, La Jolla, California 92037, USA
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Cancer Research, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Rd, La Jolla, California 92037, USA
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Metformin attenuates palmitate-induced endoplasmic reticulum stress, serine phosphorylation of IRS-1 and apoptosis in rat insulinoma cells. PLoS One 2014; 9:e97868. [PMID: 24896641 PMCID: PMC4045581 DOI: 10.1371/journal.pone.0097868] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/25/2014] [Indexed: 12/25/2022] Open
Abstract
Lipotoxicity refers to cellular dysfunctions caused by elevated free fatty acid levels playing a central role in the development and progression of obesity related diseases. Saturated fatty acids cause insulin resistance and reduce insulin production in the pancreatic islets, thereby generating a vicious cycle, which potentially culminates in type 2 diabetes. The underlying endoplasmic reticulum (ER) stress response can lead to even β-cell death (lipoapoptosis). Since improvement of β-cell viability is a promising anti-diabetic strategy, the protective effect of metformin, a known insulin sensitizer was studied in rat insulinoma cells. Assessment of palmitate-induced lipoapoptosis by fluorescent microscopy and by detection of caspase-3 showed a significant decrease in metformin treated cells. Attenuation of β-cell lipotoxicity was also revealed by lower induction/activation of various ER stress markers, e.g. phosphorylation of eukaryotic initiation factor 2α (eIF2α), c-Jun N-terminal kinase (JNK), insulin receptor substrate-1 (IRS-1) and induction of CCAAT/enhancer binding protein homologous protein (CHOP). Our results indicate that the β-cell protective activity of metformin in lipotoxicity can be at least partly attributed to suppression of ER stress.
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Abstract
Free fatty acids (FFAs) exert both positive and negative effects on beta cell survival and insulin secretory function, depending on concentration, duration, and glucose abundance. Lipid signals are mediated not only through metabolic pathways, but also through cell surface and nuclear receptors. Toxicity is modulated by positive signals arising from circulating factors such as hormones, growth factors and incretins, as well as negative signals such as inflammatory mediators and cytokines. Intracellular mechanisms of lipotoxicity include metabolic interference and cellular stress responses such as oxidative stress, endoplasmic reticulum (ER) stress, and possibly autophagy. New findings strengthen an old hypothesis that lipids may also impair compensatory beta cell proliferation. Clinical observations continue to support a role for lipid biology in the risk and progression of both type 1 (T1D) and type 2 diabetes (T2D). This review summarizes recent work in this important, rapidly evolving field.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
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Lee YS, Jun HS. Anti-diabetic actions of glucagon-like peptide-1 on pancreatic beta-cells. Metabolism 2014; 63:9-19. [PMID: 24140094 DOI: 10.1016/j.metabol.2013.09.010] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 09/05/2013] [Accepted: 09/14/2013] [Indexed: 12/11/2022]
Abstract
Glucagon-like peptide-1 (GLP-1), an incretin hormone, is released from intestinal L-cells in response to nutrients. GLP-1 lowers blood glucose levels by stimulating insulin secretion from pancreatic beta-cells in a glucose-dependent manner. In addition, GLP-1 slows gastric emptying, suppresses appetite, reduces plasma glucagon, and stimulates glucose disposal, which are beneficial for glucose homeostasis. Therefore, incretin-based therapies such as GLP-1 receptor agonists and inhibitors of dipeptidyl peptidase IV, an enzyme which inactivates GLP-1, have been developed for treatment of diabetes. This review outlines our knowledge of the actions of GLP-1 on insulin secretion and biosynthesis, beta-cell proliferation and regeneration, and protection against beta-cell damage, as well as the involvement of recently discovered signaling pathways of GLP-1 action, mainly focusing on pancreatic beta-cells.
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Affiliation(s)
- Young-Sun Lee
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 7-45 Songdo-dong, Yeonsu-ku, Incheon 406-840, South Korea
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