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Mannino GC, Mancuso E, Sbrignadello S, Morettini M, Andreozzi F, Tura A. Chemical Compounds and Ambient Factors Affecting Pancreatic Alpha-Cells Mass and Function: What Evidence? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16489. [PMID: 36554367 PMCID: PMC9778390 DOI: 10.3390/ijerph192416489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
The exposure to different substances present in the environment can affect the ability of the human body to maintain glucose homeostasis. Some review studies summarized the current evidence about the relationships between environment and insulin resistance or beta-cell dysfunction. Instead, no reviews focused on the relationships between the environment and the alpha cell, although in recent years clear indications have emerged for the pivotal role of the alpha cell in glucose regulation. Thus, the aim of this review was to analyze the studies about the effects of chemical, biological, and physical environmental factors on the alpha cell. Notably, we found studies focusing on the effects of different categories of compounds, including air pollutants, compounds of known toxicity present in common objects, pharmacological agents, and compounds possibly present in food, plus studies on the effects of physical factors (mainly heat exposure). However, the overall number of relevant studies was limited, especially when compared to studies related to the environment and insulin sensitivity or beta-cell function. In our opinion, this was likely due to the underestimation of the alpha-cell role in glucose homeostasis, but since such a role has recently emerged with increasing strength, we expect several new studies about the environment and alpha-cell in the near future.
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Affiliation(s)
- Gaia Chiara Mannino
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Elettra Mancuso
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | | | - Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, 60131 Ancona, Italy
| | - Francesco Andreozzi
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy
| | - Andrea Tura
- CNR Institute of Neuroscience, 35127 Padova, Italy
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2
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Wang H, Yang W, Liu J, Leng J, Li W, Yu Z, Li J, Ma RCW, Hu G, Fang Z, Wang Y, Yang X. Serum concentrations of SFAs and CDKAL1 single-nucleotide polymorphism rs7747752 are related to an increased risk of gestational diabetes mellitus. Am J Clin Nutr 2021; 114:1698-1707. [PMID: 34192303 DOI: 10.1093/ajcn/nqab225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/10/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Interactions between genetic and nutritional factors can contribute to the risk of gestational diabetes mellitus (GDM). OBJECTIVES We aimed to explore the associations of cyclin-dependent kinase 5 regulatory subunit associated protein 1-like 1 (CDKAL1) single-nucleotide polymorphism (SNP) rs7747752 and serum concentrations of SFAs with the risk of GDM in Chinese women. METHODS We conducted a 1:1 case-control study in a prospective cohort of pregnant women in Tianjin, China. Serum SFA data were collected from a total of 243 women with GDM and their controls matched by maternal age (±1 y). Among them, 207 case-control pairs had high-quality sequencing data. P/L and S/P ratios were defined as palmitic acid (16:0)/lauric acid (12:0) and stearic acid (18:0)/palmitic acid, respectively. Conditional logistic regression analysis was performed to estimate associations of CDKAL1 SNP rs7747752 and serum concentrations of SFAs with the risk of GDM. An additive interaction between rs7747752 and palmitic acid was analyzed to test the contribution of their interaction to the risk of GDM. RESULTS Among the 5 tested SFAs, palmitic acid was positively whereas lauric acid was negatively associated with the risk of GDM. A P/L ratio ≥12.2 and an S/P ratio ≤0.71 were independently and synergistically associated with an increased risk of GDM. The CDKAL1 rs7747752 G > C variant was significantly associated with an increased risk of GDM (P < 0.05). Furthermore, the presence of the rs7747752 G > C variant increased the OR (95% CI) of high palmitic acid concentration from 1.55 (0.61, 3.97) to 4.34 (2.04, 9.23), with a significant additive interaction. CONCLUSIONS The interaction between high serum palmitic acid concentration and the CDKAL1 rs7747752 G > C variant played a critical role in GDM. Given that a hypocaloric low-carbohydrate diet can lower palmitic acid concentrations, it is worthwhile to test whether such a diet is effective in reducing the risk of GDM, especially among women who have both risk factors.
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Affiliation(s)
- Hui Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Wen Yang
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Jinnan Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Junhong Leng
- Project Office, Tianjin Women and Children's Health Center, Tianjin, China
| | - Weiqin Li
- Project Office, Tianjin Women and Children's Health Center, Tianjin, China
| | - Zhijie Yu
- Population Cancer Research Program, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jing Li
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.,Tianjin Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin, China
| | - Ronald C W Ma
- Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.,Li Ka Shing Institute of Health Sciences, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Gang Hu
- Chronic Disease Epidemiology Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Zhongze Fang
- Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.,Tianjin Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin, China.,Department of Toxicology and Sanitary Chemistry, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Ying Wang
- Scientific Research Platform of the Second School of Clinical Medicine, Guangdong Medical University, Dongguan, Guangdong, China.,Key Laboratory of 3D Printing Technology in Stomatology, Guangdong Medical University, Dongguan, Guangdong, China
| | - Xilin Yang
- Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, Tianjin, China.,Tianjin Key Laboratory of Environment, Nutrition and Public Health, Tianjin, China.,Tianjin Center for International Collaborative Research on Environment, Nutrition and Public Health, Tianjin, China
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Zhang M, Yang C, Zhu M, Qian L, Luo Y, Cheng H, Geng R, Xu X, Qian C, Liu Y. Saturated fatty acids entrap PDX1 in stress granules and impede islet beta cell function. Diabetologia 2021; 64:1144-1157. [PMID: 33569632 DOI: 10.1007/s00125-021-05389-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/16/2020] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Failure of pancreatic and duodenal homeobox factor 1 (PDX1) to localise in the nucleus of islet beta cells under high-fat diet (HFD) conditions may be an early functional defect that contributes to beta cell failure in type 2 diabetes; however, the mechanism of PDX1 intracellular mislocalisation is unclear. Stress granules (SGs) are membrane-less cytoplasmic structures formed under stress that impair nucleocytoplasmic transport by sequestering nucleocytoplasmic transport factors and components of the nuclear pore complex. In this study, we investigated the stimulators that trigger SG formation in islet beta cells and the effects of SGs on PDX1 localisation and beta cell function. METHODS The effect of palmitic acid (PA) on nucleocytoplasmic transport was investigated by using two reporters, S-tdTomato and S-GFP. SG assembly in rat insulinoma cell line INS1 cells, human islets under PA stress, and the pancreas of diet-induced obese mice was analysed using immunofluorescence and immunoblotting. SG protein components were identified through mass spectrometry. SG formation was blocked by specific inhibitors or genetic deletion of essential SG proteins, and then PDX1 localisation and beta cell function were investigated in vitro and in vivo. RESULTS We showed that saturated fatty acids (SFAs) are endogenous stressors that disrupted nucleocytoplasmic transport and stimulated SG formation in pancreatic beta cells. Using mass spectrometry approaches, we revealed that several nucleocytoplasmic transport factors and PDX1 were localised to SGs after SFA treatment, which inhibited glucose-induced insulin secretion. Furthermore, we found that SFAs induced SG formation in a phosphoinositide 3-kinase (PI3K)/eukaryotic translation initiation factor 2α (EIF2α) dependent manner. Disruption of SG assembly by PI3K/EIF2α inhibitors or genetic deletion of T cell restricted intracellular antigen 1 (TIA1) in pancreatic beta cells effectively suppressed PA-induced PDX1 mislocalisation and ameliorated HFD-mediated beta cell dysfunction. CONCLUSIONS/INTERPRETATION Our findings suggest a link between SG formation and beta cell dysfunction in the presence of SFAs. Preventing SG formation may be a potential therapeutic strategy for treating obesity and type 2 diabetes.
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Affiliation(s)
- Mu Zhang
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Chunjie Yang
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Meng Zhu
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Li Qian
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Yan Luo
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Huimin Cheng
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Rong Geng
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China
| | - Xiaojun Xu
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China.
| | - Cheng Qian
- Department of Nephrology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China.
| | - Yu Liu
- Department of Endocrinology, Sir Run Run Hospital, Nanjing Medical University, Nanjing, China.
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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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Zhao X, Yoon DO, Yoo J, Park HJ. Structure-Activity Relationship Study and Biological Evaluation of 2-(Disubstituted phenyl)-indole-5-propanoic Acid Derivatives as GPR40 Full Agonists. J Med Chem 2021; 64:4130-4149. [PMID: 33769827 DOI: 10.1021/acs.jmedchem.1c00031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
G-protein-coupled receptor 40 (GPR40) is considered as an attractive drug target for treating type 2 diabetes, owing to its role in the free fatty acid-mediated increase in glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. To identify a new chemotype of GPR40 agonist, a series of 2-aryl-substituted indole-5-propanoic acid derivatives were designed and synthesized. We identified two GPR40 agonist lead compounds-4k (3-[2-(4-fluoro-2-methylphenyl)-1H-indol-5-yl]propanoic acid) and 4o (3-[2-(2,5-dimethylphenyl)-1H-indol-5-yl]propanoic acid), having GSIS and glucagon-like peptide 1 secretory effects. Unlike previously reported GPR40 partial agonists that only activate the Gq pathway, 4k and 4o activated both the Gq and Gs signaling pathways and were characterized as GPR40 full agonists. In in vivo efficacy studies, 4o significantly improved glycemic control in both C57BL/6J and db/db mice and increased plasma-active GLP-1 in C57BL/6J mice. Thus, 4o represents a promising lead for further development as a novel GPR40 full agonist against type 2 diabetes.
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Affiliation(s)
- Xiaodi Zhao
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Dong-Oh Yoon
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Jaeho Yoo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Hyun-Ju Park
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
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6
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Benito-Vicente A, Jebari-Benslaiman S, Galicia-Garcia U, Larrea-Sebal A, Uribe KB, Martin C. Molecular mechanisms of lipotoxicity-induced pancreatic β-cell dysfunction. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:357-402. [PMID: 33832653 DOI: 10.1016/bs.ircmb.2021.02.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes (T2D), a heterogeneous disorder derived from metabolic dysfunctions, leads to a glucose overflow in the circulation due to both defective insulin secretion and peripheral insulin resistance. One of the critical risk factor for T2D is obesity, which represents a global epidemic that has nearly tripled since 1975. Obesity is characterized by chronically elevated free fatty acid (FFA) levels, which cause deleterious effects on glucose homeostasis referred to as lipotoxicity. Here, we review the physiological FFA roles onto glucose-stimulated insulin secretion (GSIS) and the pathological ones affecting many steps of the mechanisms and modulation of GSIS. We also describe in vitro and in vivo experimental evidences addressing lipotoxicity in β-cells and the role of saturation and chain length of FFA on the potency of GSIS stimulation. The molecular mechanisms underpinning lipotoxic-β-cell dysfunction are also reviewed. Among them, endoplasmic reticulum stress, oxidative stress and mitochondrial dysfunction, inflammation, impaired autophagy and β-cell dedifferentiation. Finally therapeutic strategies for the β-cells dysfunctions such as the use of metformin, glucagon-like peptide 1, thiazolidinediones, anti-inflammatory drugs, chemical chaperones and weight are discussed.
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Affiliation(s)
- Asier Benito-Vicente
- Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Shifa Jebari-Benslaiman
- Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Unai Galicia-Garcia
- Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), Leioa, Spain; Department of Molecular Biophysics, Fundación Biofísica Bizkaia, Leioa, Spain
| | - Asier Larrea-Sebal
- Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), Leioa, Spain; Department of Molecular Biophysics, Fundación Biofísica Bizkaia, Leioa, Spain
| | - Kepa B Uribe
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Donostia San Sebastián, Spain
| | - Cesar Martin
- Department of Molecular Biophysics, Biofisika Institute (University of Basque Country and Consejo Superior de Investigaciones Científicas (UPV/EHU, CSIC)), Leioa, Spain; Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain.
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7
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Dobosz AM, Janikiewicz J, Borkowska AM, Dziewulska A, Lipiec E, Dobrzyn P, Kwiatek WM, Dobrzyn A. Stearoyl-CoA Desaturase 1 Activity Determines the Maintenance of DNMT1-Mediated DNA Methylation Patterns in Pancreatic β-Cells. Int J Mol Sci 2020; 21:ijms21186844. [PMID: 32961871 PMCID: PMC7555428 DOI: 10.3390/ijms21186844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 11/16/2022] Open
Abstract
Metabolic stress, such as lipotoxicity, affects the DNA methylation profile in pancreatic β-cells and thus contributes to β-cell failure and the progression of type 2 diabetes (T2D). Stearoyl-CoA desaturase 1 (SCD1) is a rate-limiting enzyme that is involved in monounsaturated fatty acid synthesis, which protects pancreatic β-cells against lipotoxicity. The present study found that SCD1 is also required for the establishment and maintenance of DNA methylation patterns in β-cells. We showed that SCD1 inhibition/deficiency caused DNA hypomethylation and changed the methyl group distribution within chromosomes in β-cells. Lower levels of DNA methylation in SCD1-deficient β-cells were followed by lower levels of DNA methyltransferase 1 (DNMT1). We also found that the downregulation of SCD1 in pancreatic β-cells led to the activation of adenosine monophosphate-activated protein kinase (AMPK) and an increase in the activity of the NAD-dependent deacetylase sirtuin-1 (SIRT1). Furthermore, the physical association between DNMT1 and SIRT1 stimulated the deacetylation of DNMT1 under conditions of SCD1 inhibition/downregulation, suggesting a mechanism by which SCD1 exerts control over DNMT1. We also found that SCD1-deficient β-cells that were treated with compound c, an inhibitor of AMPK, were characterized by higher levels of both global DNA methylation and DNMT1 protein expression compared with untreated cells. Therefore, we found that activation of the AMPK/SIRT1 signaling pathway mediates the effect of SCD1 inhibition/deficiency on DNA methylation status in pancreatic β-cells. Altogether, these findings suggest that SCD1 is a gatekeeper that protects β-cells against the lipid-derived loss of DNA methylation and provide mechanistic insights into the mechanism by which SCD1 regulates DNA methylation patterns in β-cells and T2D-relevant tissues.
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Affiliation(s)
- Aneta M. Dobosz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Justyna Janikiewicz
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Anna M. Borkowska
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
| | - Anna Dziewulska
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
| | - Ewelina Lipiec
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-348 Krakow, Poland
| | - Pawel Dobrzyn
- Laboratory of Molecular Medical Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland;
| | - Wojciech M. Kwiatek
- Division of Interdisciplinary Research, Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, Poland; (A.M.B.); (E.L.); (W.M.K.)
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland; (A.M.D.); (J.J.); (A.D.)
- Correspondence:
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Liu X, Zeng X, Chen X, Luo R, Li L, Wang C, Liu J, Cheng J, Lu Y, Chen Y. Oleic acid protects insulin-secreting INS-1E cells against palmitic acid-induced lipotoxicity along with an amelioration of ER stress. Endocrine 2019; 64:512-524. [PMID: 30778898 DOI: 10.1007/s12020-019-01867-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/08/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE It is demonstrated that unsaturated fatty acids can counteract saturated fatty acids-induced lipotoxicity, but the molecular mechanisms are unclear. In this study, we investigated the protective effects of monounsaturated oleic acid (OA) against saturated palmitic acid (PA)-induced cytotoxicity in rat β cells as well as islets, and mechanistically focused on its regulation on endoplasmic reticulum (ER) stress. METHODS Rat insulinoma cell line INS-1E cells and primary islets were treated with PA with or without OA for 24 h to determine the cell viability, apoptosis, and ER stress. SD rats were fed with high-fat diet (HFD) for 16 w, then, HFD was half replaced by olive oil to observe the protective effects of monounsaturated fatty acids rich diet. RESULTS We demonstrated that PA impaired cell viability and insulin secretion of INS-1E cells and rat islets, but OA robustly rescued cells from cell death. OA substantially alleviated either PA or chemical ER stressors (thapsigargin or tunicamycin)-induced ER stress. Importantly, OA attenuated the activity of PERK-eIF2α-ATF4-CHOP pathway and regulated the ER Ca2+ homeostasis. In vivo, only olive oil supplementation did not cause significant changes, while high-fat diet (HFD) for 32 w obviously induced islets ER stress and impaired insulin sensitivity in SD rats. Half replacement of HFD with olive oil (a mixed diet) has ameliorated this effect. CONCLUSION OA alleviated PA-induced lipotoxicity in INS-1E cells and improved insulin sensitivity in HFD rats. The amelioration of PA triggered ER stress may be responsible for its beneficial effects in β cells.
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Affiliation(s)
- Xiaohong Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Xin Zeng
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Xuanming Chen
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Ruixi Luo
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Linzhao Li
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Chengshi Wang
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jingping Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jingqiu Cheng
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Yanrong Lu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Younan Chen
- Key Laboratory of Transplant Engineering and Immunology, NHFPC; Regenerative Medicine Research Center, Endocrinology Department, West China Hospital, Sichuan University, Chengdu, P.R. China.
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Pinto LC, Cerqueira-Lima AT, Suzarth SDS, de Souza R, Tosta BR, da Silva HB, Pires ADO, Queiroz GDA, Teixeira TO, Dourado KMC, Costa VO, Baqueiro V, Oliveira DP, Brandão HR, de Souza CO, Druzian JI, Medeiros KCDP, Dantas Alves CDA, Lopes MV, Figueiredo CAV. Anonna muricata L. (soursop) seed oil improves type 1 diabetes parameters in vivo and in vitro. PHARMANUTRITION 2018. [DOI: 10.1016/j.phanu.2017.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Effect of Saturated Stearic Acid on MAP Kinase and ER Stress Signaling Pathways during Apoptosis Induction in Human Pancreatic β-Cells Is Inhibited by Unsaturated Oleic Acid. Int J Mol Sci 2017; 18:ijms18112313. [PMID: 29099080 PMCID: PMC5713282 DOI: 10.3390/ijms18112313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 10/27/2017] [Accepted: 10/31/2017] [Indexed: 12/13/2022] Open
Abstract
It has been shown that saturated fatty acids (FAs) have a detrimental effect on pancreatic β-cells function and survival, leading to apoptosis, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction and regulation by FAs in β-cells remain unclear; however, mitogen-activated protein (MAP) kinase and endoplasmic reticulum (ER) stress signaling pathways may be involved. In this study, we tested how unsaturated oleic acid (OA) affects the effect of saturated stearic acid (SA) on the p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways as well as the ER stress signaling pathways during apoptosis induction in the human pancreatic β-cells NES2Y. We demonstrated that OA is able to inhibit all effects of SA. OA alone has only minimal or no effects on tested signaling in NES2Y cells. The point of OA inhibitory intervention in SA-induced apoptotic signaling thus seems to be located upstream of the discussed signaling pathways.
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Pallebage-Gamarallage M, Takechi R, Lam V, Elahy M, Mamo J. Pharmacological modulation of dietary lipid-induced cerebral capillary dysfunction: Considerations for reducing risk for Alzheimer's disease. Crit Rev Clin Lab Sci 2015; 53:166-83. [PMID: 26678521 DOI: 10.3109/10408363.2015.1115820] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An increasing body of evidence suggests that cerebrovascular dysfunction and microvessel disease precede the evolution of hallmark pathological features that characterise Alzheimer's disease (AD), consistent with a causal association for onset or progression. Recent studies, principally in genetically unmanipulated animal models, suggest that chronic ingestion of diets enriched in saturated fats and cholesterol may compromise blood-brain barrier (BBB) integrity resulting in inappropriate blood-to-brain extravasation of plasma proteins, including lipid macromolecules that may be enriched in amyloid-β (Aβ). Brain parenchymal retention of blood proteins and lipoprotein bound Aβ is associated with heightened neurovascular inflammation, altered redox homeostasis and nitric oxide (NO) metabolism. Therefore, it is a reasonable proposition that lipid-lowering agents may positively modulate BBB integrity and by extension attenuate risk or progression of AD. In addition to their robust lipid lowering properties, reported beneficial effects of lipid-lowering agents were attributed to their pleiotropic properties via modulation of inflammation, oxidative stress, NO and Aβ metabolism. The review is a contemporary consideration of a complex body of literature intended to synthesise focussed consideration of mechanisms central to regulation of BBB function and integrity. Emphasis is given to dietary fat driven significant epidemiological evidence consistent with heightened risk amongst populations consuming greater amounts of saturated fats and cholesterol. In addition, potential neurovascular benefits associated with the use of hypolipidemic statins, probucol and fenofibrate are also presented in the context of lipid-lowering and pleiotropic properties.
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Affiliation(s)
- Menuka Pallebage-Gamarallage
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Ryusuke Takechi
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Virginie Lam
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Mina Elahy
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - John Mamo
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
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Elahy M, Lam V, Pallebage-Gamarallage MM, Giles C, Mamo JCL, Takechi R. Nicotine Attenuates Disruption of Blood–Brain Barrier Induced by Saturated-Fat Feeding in Wild-Type Mice. Nicotine Tob Res 2015; 17:1436-41. [DOI: 10.1093/ntr/ntv044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 02/15/2015] [Indexed: 02/07/2023]
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Kim IS, Yang SY, Han JH, Jung SH, Park HS, Myung CS. Differential Gene Expression in GPR40-Overexpressing Pancreatic β-cells Treated with Linoleic Acid. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2015; 19:141-9. [PMID: 25729276 PMCID: PMC4342734 DOI: 10.4196/kjpp.2015.19.2.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 01/20/2023]
Abstract
"G protein-coupled receptor 40" (GPR40), a receptor for long-chain fatty acids, mediates the stimulation of glucose-induced insulin secretion. We examined the profiles of differential gene expression in GPR40-activated cells treated with linoleic acid, and finally predicted the integral pathways of the cellular mechanism of GPR40-mediated insulinotropic effects. After constructing a GPR40-overexpressing stable cell line (RIN-40) from the rat pancreatic β-cell line RIN-5f, we determined the gene expression profiles of RIN-5f and RIN-40. In total, 1004 genes, the expression of which was altered at least twofold, were selected in RIN-5f versus RIN-40. Moreover, the differential genetic profiles were investigated in RIN-40 cells treated with 30 µM linoleic acid, which resulted in selection of 93 genes in RIN-40 versus RIN-40 treated with linoleic acid. Based on the Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG, http://www.genome.jp/kegg/), sets of genes induced differentially by treatment with linoleic acid in RIN-40 cells were found to be related to mitogen-activated protein (MAP) kinase- and neuroactive ligand-receptor interaction pathways. A gene ontology (GO) study revealed that more than 30% of the genes were associated with signal transduction and cell proliferation. Thus, this study elucidated a gene expression pattern relevant to the signal pathways that are regulated by GPR40 activation during the acute period. Together, these findings increase our mechanistic understanding of endogenous molecules associated with GPR40 function, and provide information useful for identification of a target for the management of type 2 diabetes mellitus.
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Affiliation(s)
- In-Su Kim
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea
| | - So-Young Yang
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea. ; Institute of Drug Research & Development, Chungnam National University, Daejeon 305-764, Korea
| | - Joo-Hui Han
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea
| | - Sang-Hyuk Jung
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea
| | - Hyun-Soo Park
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea
| | - Chang-Seon Myung
- Department of Pharmacology, Chungnam National University College of Pharmacy, Daejeon 305-764, Korea. ; Institute of Drug Research & Development, Chungnam National University, Daejeon 305-764, Korea
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Bermudez B, Ortega-Gomez A, Varela LM, Villar J, Abia R, Muriana FJG, Lopez S. Clustering effects on postprandial insulin secretion and sensitivity in response to meals with different fatty acid compositions. Food Funct 2015; 5:1374-80. [PMID: 24752559 DOI: 10.1039/c4fo00067f] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Dietary fatty acids play a role in glucose homeostasis. The aim of this study was to assess the individual relationship between dietary saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids with postprandial β-cell function and insulin sensitivity in subjects with normal and high fasting triglycerides. We assessed postprandial β-cell function (by the insulinogenic index and the ratio of the insulin to glucose areas under the time-concentration curve) and insulin sensitivity (by the oral glucose and the minimal model insulin sensitivity indices) over four nonconsecutive, randomly assigned, high-fat meals containing a panel of SFA (palmitic and stearic acids), MUFA (palmitoleic and oleic acids) and PUFA (linoleic and α-linolenic acids) in 14 subjects with normal and in 14 subjects with high fasting triglycerides. The proportions of each fatty acid in the meals and the values for surrogate measures of postprandial β-cell function and insulin sensitivity were subjected to a Pearson correlation and hierarchical cluster analysis, which revealed two classes of dietary fatty acids for regulating postprandial glucose homeostasis. We successfully discriminated the adverse effects of SFA palmitic acid from the beneficial effects of MUFA oleic acid on postprandial β-cell function (r ≥ 0.84 for SFA palmitic acid and r ≥ -0.71 for MUFA oleic acid; P < 0.05) and insulin sensitivity (r ≥ -0.92 for SFA palmitic acid and r ≥ 0.89 for MUFA oleic acid; P < 0.001) both in subjects with normal and high fasting triglycerides. In conclusion, dietary MUFA oleic acid, in contrast to SFA palmitic acid, favours the tuning towards better postprandial glycaemic control in subjects with normal and high fasting triglycerides.
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Affiliation(s)
- Beatriz Bermudez
- Laboratory of Cellular and Molecular Nutrition, Instituto de la Grasa, CSIC, Avda. Padre Garcia Tejero 4, 41012 Seville, Spain.
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Hall E, Volkov P, Dayeh T, Bacos K, Rönn T, Nitert MD, Ling C. Effects of palmitate on genome-wide mRNA expression and DNA methylation patterns in human pancreatic islets. BMC Med 2014; 12:103. [PMID: 24953961 PMCID: PMC4065864 DOI: 10.1186/1741-7015-12-103] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/25/2014] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Circulating free fatty acids are often elevated in patients with type 2 diabetes (T2D) and obese individuals. Chronic exposure to high levels of saturated fatty acids has detrimental effects on islet function and insulin secretion. Altered gene expression and epigenetics may contribute to T2D and obesity. However, there is limited information on whether fatty acids alter the genome-wide transcriptome profile in conjunction with DNA methylation patterns in human pancreatic islets. To dissect the molecular mechanisms linking lipotoxicity to impaired insulin secretion, we investigated the effects of a 48 h palmitate treatment in vitro on genome-wide mRNA expression and DNA methylation patterns in human pancreatic islets. METHODS Genome-wide mRNA expression was analyzed using Affymetrix GeneChip(®) Human Gene 1.0 ST whole transcript-based array (n = 13) and genome-wide DNA methylation was analyzed using Infinium HumanMethylation450K BeadChip (n = 13) in human pancreatic islets exposed to palmitate or control media for 48 h. A non-parametric paired Wilcoxon statistical test was used to analyze mRNA expression. Apoptosis was measured using Apo-ONE(®) Homogeneous Caspase-3/7 Assay (n = 4). RESULTS While glucose-stimulated insulin secretion was decreased, there was no significant effect on apoptosis in human islets exposed to palmitate. We identified 1,860 differentially expressed genes in palmitate-treated human islets. These include candidate genes for T2D, such as TCF7L2, GLIS3, HNF1B and SLC30A8. Additionally, genes in glycolysis/gluconeogenesis, pyruvate metabolism, fatty acid metabolism, glutathione metabolism and one carbon pool by folate were differentially expressed in palmitate-treated human islets. Palmitate treatment altered the global DNA methylation level and DNA methylation levels of CpG island shelves and shores, 5'UTR, 3'UTR and gene body regions in human islets. Moreover, 290 genes with differential expression had a corresponding change in DNA methylation, for example, TCF7L2 and GLIS3. Importantly, out of the genes differentially expressed due to palmitate treatment in human islets, 67 were also associated with BMI and 37 were differentially expressed in islets from T2D patients. CONCLUSION Our study demonstrates that palmitate treatment of human pancreatic islets gives rise to epigenetic modifications that together with altered gene expression may contribute to impaired insulin secretion and T2D.
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Affiliation(s)
| | | | | | | | | | | | - Charlotte Ling
- Epigenetics and Diabetes Unit, Department of Clinical Sciences, Lund University Diabetes Centre, CRC, Lund University, Scania University Hospital, Malmö, Sweden.
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Yabuki C, Komatsu H, Tsujihata Y, Maeda R, Ito R, Matsuda-Nagasumi K, Sakuma K, Miyawaki K, Kikuchi N, Takeuchi K, Habata Y, Mori M. A novel antidiabetic drug, fasiglifam/TAK-875, acts as an ago-allosteric modulator of FFAR1. PLoS One 2013; 8:e76280. [PMID: 24130766 PMCID: PMC3794927 DOI: 10.1371/journal.pone.0076280] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/22/2013] [Indexed: 01/23/2023] Open
Abstract
Selective free fatty acid receptor 1 (FFAR1)/GPR40 agonist fasiglifam (TAK-875), an antidiabetic drug under phase 3 development, potentiates insulin secretion in a glucose-dependent manner by activating FFAR1 expressed in pancreatic β cells. Although fasiglifam significantly improved glycemic control in type 2 diabetes patients with a minimum risk of hypoglycemia in a phase 2 study, the precise mechanisms of its potent pharmacological effects are not fully understood. Here we demonstrate that fasiglifam acts as an ago-allosteric modulator with a partial agonistic activity for FFAR1. In both Ca2+ influx and insulin secretion assays using cell lines and mouse islets, fasiglifam showed positive cooperativity with the FFAR1 ligand γ-linolenic acid (γ-LA). Augmentation of glucose-induced insulin secretion by fasiglifam, γ-LA, or their combination was completely abolished in pancreatic islets of FFAR1-knockout mice. In diabetic rats, the insulinotropic effect of fasiglifam was suppressed by pharmacological reduction of plasma free fatty acid (FFA) levels using a lipolysis inhibitor, suggesting that fasiglifam potentiates insulin release in conjunction with plasma FFAs in vivo. Point mutations of FFAR1 differentially affected Ca2+ influx activities of fasiglifam and γ-LA, further indicating that these agonists may bind to distinct binding sites. Our results strongly suggest that fasiglifam is an ago-allosteric modulator of FFAR1 that exerts its effects by acting cooperatively with endogenous plasma FFAs in human patients as well as diabetic animals. These findings contribute to our understanding of fasiglifam as an attractive antidiabetic drug with a novel mechanism of action.
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Affiliation(s)
- Chiori Yabuki
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
- * E-mail:
| | - Hidetoshi Komatsu
- Central Nervous System Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Yoshiyuki Tsujihata
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Risa Maeda
- Central Nervous System Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Ryo Ito
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Kae Matsuda-Nagasumi
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Kensuke Sakuma
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Kazumasa Miyawaki
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Naoya Kikuchi
- Central Nervous System Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Koji Takeuchi
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Yugo Habata
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Masaaki Mori
- Cardiovascular and Metabolic Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
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Takechi R, Galloway S, Pallebage-Gamarallage MM, Lam V, Dhaliwal SS, Mamo JC. Probucol prevents blood-brain barrier dysfunction in wild-type mice induced by saturated fat or cholesterol feeding. Clin Exp Pharmacol Physiol 2013; 40:45-52. [PMID: 23167559 DOI: 10.1111/1440-1681.12032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 10/24/2012] [Accepted: 11/15/2012] [Indexed: 01/08/2023]
Abstract
Dysfunction of the blood-brain barrier (BBB) is an early pathological feature of vascular dementia and Alzheimer's disease (AD) and is triggered by inflammatory stimuli. Probucol is a lipid-lowering agent with potent anti-oxidant properties once commonly used for the treatment of cardiovascular disease. Probucol therapy was found to stabilize cognitive symptoms in elderly AD patients, whereas in amyloid transgenic mice probucol was shown to attenuate amyloidosis. However, the mechanisms underlying the effects of probucol have note been determined. In the present study we investigated whether probucol can prevent BBB disturbances induced by chronic ingestion of proinflammatory diets enriched with either 20% (w/w) saturated fats (SFA) or 1% (w/w) cholesterol. Mice were fed the diets for 12 weeks before they were killed and BBB integrity was measured. Mice maintained on either the SFA- or cholesterol-supplemented diets were found to have a 30- and sevenfold greater likelihood of BBB dysfunction, respectively, as determined by the parenchymal extravasation of plasma-derived immunoglobulins and endogenous lipoprotein enrichment with β-amyloid. In contrast, mice fed the SFA- or cholesterol-enriched diets that also contained 1% (w/w) probucol showed no evidence of BBB disturbance. The parenchymal expression of glial fibrillary acidic protein, a marker of cerebrovascular inflammation, was significantly greater in mice fed the SFA-enriched diet. Plasma lipid, β-amyloid and apolipoprotein B levels were not increased by feeding of the SFA- or cholesterol-enriched diets. However, mice fed the SFA- or cholesterol-enriched diets did exhibit increased plasma non-esterified fatty acid levels that were not reduced by probucol. The data suggest that probucol prevents disturbances of BBB induced by chronic ingestion of diets enriched in SFA or cholesterol by suppressing inflammatory pathways rather than by modulating plasma lipid homeostasis.
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Affiliation(s)
- Ryusuke Takechi
- Faculty of Health Sciences, School of Public Health, Curtin Health Innovation Research Institute Biosciences Research Precinct, Curtin University, Bentley, WA, Australia
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Ferreira MR, Chicco A, Lombardo YB. Dietary fish oil normalized glucose-stimulated insulin secretion in isolated pancreatic islets of dyslipemic rats through mechanisms involving glucose phosphorylation, peroxisome proliferator-activated receptor γ and uncoupling protein 2. Prostaglandins Leukot Essent Fatty Acids 2013; 89:31-8. [PMID: 23706675 DOI: 10.1016/j.plefa.2013.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/04/2013] [Accepted: 04/06/2013] [Indexed: 11/18/2022]
Abstract
This study evaluates some possible mechanisms behind the beneficial effects of dietary fish oil (FO) on β cell dysfunction in rats fed a sucrose-rich diet (SRD). Rats were fed a SRD for 6 months. Thereafter, half the rats received a SRD in which corn oil was partially replaced by FO up to 8 months. The other half continued consuming the SRD up to 8 months. A control group was fed a control diet throughout the experimental period. In isolated islets of SRD-fed rats dietary FO normalized the reduced glucose phosphorylation, the altered glucose oxidation, the triglyceride content, the increased protein mass levels of peroxisome proliferator-activated receptor γ (PPARγ) and uncoupling protein 2 without changes in GLUT2 and PPARα. These finding suggest that the changes mentioned above could be involved in the normalization of the altered glucose-stimulated insulin secretion pattern in this nutritional model of dyslipidemia and insulin resistance.
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Affiliation(s)
- M R Ferreira
- Department of Biochemistry, School of Biochemistry, University of Litoral. Ciudad Universitaria Paraje El Pozo CC 242 (3000) Santa Fe, Argentina
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Takechi R, Pallebage-Gamarallage MM, Lam V, Giles C, Mamo JC. Aging-related changes in blood-brain barrier integrity and the effect of dietary fat. NEURODEGENER DIS 2012; 12:125-35. [PMID: 23128303 DOI: 10.1159/000343211] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 09/06/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Disturbances in blood-brain barrier (BBB) integrity contribute to the onset and progression of neurodegenerative diseases including Alzheimer's disease (AD) and vascular dementia (VaD). Aging is positively associated with AD and VaD risk, but this may reflect comorbidities or the effects of other chronic modulators of vascular function such as diet. OBJECTIVE To explore putative synergistic effects of aging with diet, in this study genetically unmanipulated mice were maintained on diets enriched in saturated fatty acids (SFA) or cholesterol and compared to mice provided with low-fat (LF) feed formula. METHODS The functional integrity of the BBB was assessed following 3, 6 and 12 months of dietary intervention commenced at 6 weeks of age, by determining the brain parenchymal extravasation of immunoglobulin G (IgG). RESULTS Mice maintained on the SFA- or cholesterol-enriched diet showed significant parenchymal IgG abundance following 3 months of feeding, concomitant with diminished expression of the tight junction protein occludin. LF control mice had essentially no evidence of BBB disturbances. Six months of SFA feeding exacerbated the difference in IgG abundance compared to the LF mice. At 12 months of feeding, the control LF mice also had significant parenchymal IgG that was comparable to mice fed the SFA- or cholesterol-enriched diet for 3 months. However, there may have been an adaptation to the fat-enriched diets because SFA and cholesterol did not exacerbate IgG parenchymal accumulation beyond 6 months of feeding. CONCLUSION Collectively, the study suggests that diets enriched in SFA or cholesterol accelerate the onset of BBB dysfunction that otherwise occurs with aging.
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Affiliation(s)
- R Takechi
- Curtin Health Innovation Research Institute, Faculty of Health Science, School of Public Health, Curtin University, Perth, W.A., Australia
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Murea M, Ma L, Freedman BI. Genetic and environmental factors associated with type 2 diabetes and diabetic vascular complications. Rev Diabet Stud 2012; 9:6-22. [PMID: 22972441 DOI: 10.1900/rds.2012.9.6] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Faced with a global epidemic of type 2 diabetes (T2D), it is critical that researchers improve our understanding of the pathogenesis of T2D and related vascular complications. These findings may ultimately lead to novel treatment options for disease prevention or delaying progression. Two major paradigms jointly underlie the development of T2D and related coronary artery disease, diabetic nephropathy, and diabetic retinopathy. These paradigms include the genetic risk variants and behavioral/environmental factors. This article systematically reviews the literature supporting genetic determinants in the pathogenesis of T2D and diabetic vasculopathy, and the functional implications of these gene variants on the regulation of beta-cell function and glucose homeostasis. We update the discovery of diabetes and diabetic vasculopathy risk variants, and describe the genetic technologies that have uncovered them. Also, genomic linkage between obesity and T2D is discussed. There is a complementary role for behavioral and environmental factors modulating the genetic susceptibility and diabetes risk. Epidemiological and clinical data demonstrating the effects of behavioral and novel environmental exposures on disease expression are reviewed. Finally, a succinct overview of recent landmark clinical trials addressing glycemic control and its impact on rates of vascular complications is presented. It is expected that novel strategies to exploit the gene- and exposure-related underpinnings of T2D will soon result.
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Affiliation(s)
- Mariana Murea
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
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Negoro N, Sasaki S, Mikami S, Ito M, Tsujihata Y, Ito R, Suzuki M, Takeuchi K, Suzuki N, Miyazaki J, Santou T, Odani T, Kanzaki N, Funami M, Morohashi A, Nonaka M, Matsunaga S, Yasuma T, Momose Y. Optimization of (2,3-dihydro-1-benzofuran-3-yl)acetic acids: discovery of a non-free fatty acid-like, highly bioavailable G protein-coupled receptor 40/free fatty acid receptor 1 agonist as a glucose-dependent insulinotropic agent. J Med Chem 2012; 55:3960-74. [PMID: 22490067 DOI: 10.1021/jm300170m] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
G protein-coupled receptor 40 (GPR40)/free fatty acid receptor 1 (FFA1) is a free fatty acid (FFA) receptor that mediates FFA-amplified glucose-stimulated insulin secretion in pancreatic β-cells. We previously identified (2,3-dihydro-1-benzofuran-3-yl)acetic acid derivative 2 as a candidate, but it had relatively high lipophilicity. Adding a polar functional group on 2 yielded several compounds with lower lipophilicity and little effect on caspase-3/7 activity at 30 μM (a marker of toxicity in human HepG2 hepatocytes). Three optimized compounds showed promising pharmacokinetic profiles with good in vivo effects. Of these, compound 16 had the lowest lipophilicity. Metabolic analysis of 16 showed a long-acting PK profile due to high resistance to β-oxidation. Oral administration of 16 significantly reduced plasma glucose excursion and increased insulin secretion during an OGTT in type 2 diabetic rats. Compound 16 (TAK-875) is being evaluated in human clinical trials for the treatment of type 2 diabetes.
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Affiliation(s)
- Nobuyuki Negoro
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
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Protective effects of arachidonic acid against palmitic acid-mediated lipotoxicity in HIT-T15 cells. Mol Cell Biochem 2011; 364:19-28. [DOI: 10.1007/s11010-011-1200-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/15/2011] [Indexed: 01/03/2023]
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A diet enriched in docosahexanoic Acid exacerbates brain parenchymal extravasation of apo B lipoproteins induced by chronic ingestion of saturated fats. Int J Vasc Med 2011; 2012:647689. [PMID: 22121489 PMCID: PMC3216294 DOI: 10.1155/2012/647689] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/04/2011] [Accepted: 08/26/2011] [Indexed: 12/03/2022] Open
Abstract
Chronic ingestion of saturated fatty acids (SFAs) was previously shown to compromise blood-brain barrier integrity, leading to brain parenchymal extravasation of apolipoprotein B (apo B) lipoproteins enriched in amyloid beta. In contrast, diets enriched in mono- or polyunsaturated (PUFA) oils had no detrimental effect. Rather, n3 and n6 oils generally confer protection via suppression of inflammation. This study investigated in wild-type mice if a PUFA diet enriched in docosahexanoic acid (DHA) restored blood-brain barrier integrity and attenuated parenchymal apo B abundance induced by chronic ingestion of SFA. Cerebrovascular leakage of apo B was quantitated utilising immunofluorescent staining. The plasma concentration of brain-derived S100β was measured as a marker of cerebrovascular inflammation. In mice fed SFA for 3 months, provision thereafter of a DHA-enriched diet exacerbated parenchymal apo B retention, concomitant with a significant increase in plasma cholesterol. In contrast, provision of a low-fat diet following chronic SFA feeding had no effect on SFA-induced parenchymal apo B. The findings suggest that in a heightened state of cerebrovascular inflammation, the provision of unsaturated fatty acids may be detrimental, possibly as a consequence of a greater susceptibility for oxidation.
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Mechanisms and implications of age-related changes in the liver: nonalcoholic Fatty liver disease in the elderly. Curr Gerontol Geriatr Res 2011; 2011:831536. [PMID: 21918648 PMCID: PMC3171768 DOI: 10.1155/2011/831536] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/09/2011] [Indexed: 12/11/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is hepatic steatosis associated with metabolic abnormalities such as overweight/central obesity, insulin resistance, type 2 diabetes (T2D), and dyslipidemia. NAFLD is becoming the most common liver disease in contemporary society, with the highest prevalence in those over 60 years. NAFLD pathology ranges from simple steatosis to a necroinflammatory fibrosing disorder called steatohepatitis (SH), the latter associated with high risk of developing cirrhosis, often occuring in the seventh to ninth decades of life. While the main health implications of NAFLD are increased risk of developing T2D, cardiovascular diseases, and common cancers, there is substantantially increased standardized mortality, and deaths from decompensated cirrhosis and hepatocellular carcinoma (HCC). Little is known about the interactive effects of ageing and NAFLD, with most studies focusing on the younger population. This paper summarises the epidemiology, pathogenesis, and clinical course of NAFLD, with particular attention to persons over age 60 years. An approach to the management of NASH and its complications in the elderly, will also be presented here.
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Tsujihata Y, Ito R, Suzuki M, Harada A, Negoro N, Yasuma T, Momose Y, Takeuchi K. TAK-875, an orally available G protein-coupled receptor 40/free fatty acid receptor 1 agonist, enhances glucose-dependent insulin secretion and improves both postprandial and fasting hyperglycemia in type 2 diabetic rats. J Pharmacol Exp Ther 2011; 339:228-37. [PMID: 21752941 DOI: 10.1124/jpet.111.183772] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G protein-coupled receptor 40/free fatty acid receptor 1 (GPR40/FFA(1)) is highly expressed in pancreatic β cells and mediates free fatty acid-induced insulin secretion. This study examined the pharmacological effects and potential for avoidance of lipotoxicity of [(3S)-6-({2',6'-dimethyl-4'-[3-(methylsulfonyl)propoxy]biphenyl-3-yl}meth-oxy)-2,3-dihydro-1-benzofuran-3-yl]acetic acid hemi-hydrate) (TAK-875), a novel, orally available, selective GPR40 agonist. Insulinoma cell lines and primary rat islets were used to assess the effects of TAK-875 in vitro. The in vivo effects of TAK-875 on postprandial hyperglycemia, fasting hyperglycemia, and normoglycemia were examined in type 2 diabetic and normal rats. In rat insulinoma INS-1 833/15 cells, TAK-875 increased intracellular inositol monophosphate and calcium concentration, consistent with activation of the Gqα signaling pathway. The insulinotropic action of TAK-875 (10 μM) in INS-1 833/15 and primary rat islets was glucose-dependent. Prolonged exposure of cytokine-sensitive INS-1 832/13 to TAK-875 for 72 h at pharmacologically active concentrations did not alter glucose-stimulated insulin secretion, insulin content, or caspase 3/7 activity, whereas prolonged exposure to palmitic or oleic acid impaired β cell function and survival. In an oral glucose tolerance test in type 2 diabetic N-STZ-1.5 rats, TAK-875 (1-10 mg/kg p.o.) showed a clear improvement in glucose tolerance and augmented insulin secretion. In addition, TAK-875 (10 mg/kg, p.o.) significantly augmented plasma insulin levels and reduced fasting hyperglycemia in male Zucker diabetic fatty rats, whereas in fasted normal Sprague-Dawley rats, TAK-875 neither enhanced insulin secretion nor caused hypoglycemia even at 30 mg/kg. TAK-875 enhances glucose-dependent insulin secretion and improves both postprandial and fasting hyperglycemia with a low risk of hypoglycemia and no evidence of β cell toxicity.
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Affiliation(s)
- Yoshiyuki Tsujihata
- Metabolic Disease Drug Discovery Unit,Takeda Pharmaceutical Company Limited, Osaka, Japan.
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Huang J, Viswakarma N, Yu S, Jia Y, Bai L, Vluggens A, Cherkaoui-Malki M, Khan M, Singh I, Yang G, Rao MS, Borensztajn J, Reddy JK. Progressive endoplasmic reticulum stress contributes to hepatocarcinogenesis in fatty acyl-CoA oxidase 1-deficient mice. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:703-13. [PMID: 21801867 DOI: 10.1016/j.ajpath.2011.04.030] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 04/20/2011] [Accepted: 04/25/2011] [Indexed: 02/08/2023]
Abstract
Fatty acyl-coenzyme A oxidase 1 (ACOX1) knockout (ACOX1(-/-)) mice manifest hepatic metabolic derangements that lead to the development of steatohepatitis, hepatocellular regeneration, spontaneous peroxisome proliferation, and hepatocellular carcinomas. Deficiency of ACOX1 results in unmetabolized substrates of this enzyme that function as biological ligands for peroxisome proliferator-activated receptor-α (PPARα) in liver. Here we demonstrate that sustained activation of PPARα in ACOX1(-/-) mouse liver by these ACOX1 substrates results in endoplasmic reticulum (ER) stress. Overexpression of transcriptional regulator p8 and its ER stress-related effectors such as the pseudokinase tribbles homolog 3, activating transcription factor 4, and transcription factor CCAAT/-enhancer-binding protein homologous protein as well as phosphorylation of eukaryotic translation initiation factor 2α, indicate the induction of unfolded protein response signaling in the ACOX1(-/-) mouse liver. We also show here that, in the liver, p8 is a target for all three PPAR isoforms (-α, -β, and -γ), which interact with peroxisome proliferator response elements in p8 promoter. Sustained activation of p8 and unfolded protein response-associated ER stress in ACOX1(-/-) mouse liver contributes to hepatocyte apoptosis and liver cell proliferation culminating in the development of hepatocarcinogenesis. We also demonstrate that human ACOX1 transgene is functional in ACOX1(-/-) mice and effectively prevents metabolic dysfunctions that lead to ER stress and carcinogenic effects. Taken together, our data indicate that progressive PPARα- and p8-mediated ER stress contribute to the hepatocarcinogenesis in ACOX1(-/-) mice.
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Affiliation(s)
- Jiansheng Huang
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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El-Ansary AK, Bacha AGB, Al-Ayahdi LY. Plasma fatty acids as diagnostic markers in autistic patients from Saudi Arabia. Lipids Health Dis 2011; 10:62. [PMID: 21510882 PMCID: PMC3107800 DOI: 10.1186/1476-511x-10-62] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 04/21/2011] [Indexed: 11/10/2022] Open
Abstract
Backgrounds Autism is a family of developmental disorders of unknown origin. The disorder is characterized by behavioral, developmental, neuropathological and sensory abnormalities, and is usually diagnosed between the ages of 2 and 10 with peak prevalence rates observed in children aged 5-8 years. Recently, there has been heightened interest in the role of plasma free fatty acids (FA) in the pathology of neurological disorders. The aim of this study is to compare plasma fatty acid profiles of Saudi autistic patients with those of age-matching control subjects in an attempt to clarify the role of FA in the etiology of autism. Methods 26 autistic patients together with 26-age-matching controls were enrolled in the present study. Methyl esters of FA were extracted with hexane, and the fatty acid composition of the extract was analyzed on a gas chromatography. Results The obtained data proved that fatty acids are altered in the plasma of autistic patients, specifically showing an increase in most of the saturated fatty acids except for propionic acid, and a decrease in most of polyunsaturated fatty acids. The altered fatty acid profile was discussed in relation to oxidative stress, mitochondrial dysfunction and the high lead (Pb) concentration previously reported in Saudi autistic patients. Statistical analysis of the obtained data shows that most of the measured fatty acids were significantly different in autistic patients compared to age -matching controls. Conclusions Receiver Operating Characteristic (ROC) curve analysis shows satisfactory values of area under the curve (AUC) which could reflect the high degree of specificity and sensitivity of the altered fatty acids as biomarkers in autistic patients from Saudi Arabia.
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Affiliation(s)
- Afaf K El-Ansary
- Biochemistry Department, Science College, King Saud University, P,O Box 22452, Zip Code 11495, Riyadh, Saudi Arabia.
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Effects of human serum albumin complexed with free fatty acids on cell viability and insulin secretion in the hamster pancreatic β-cell line HIT-T15. Life Sci 2011; 88:810-8. [PMID: 21396379 DOI: 10.1016/j.lfs.2011.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/29/2011] [Accepted: 02/17/2011] [Indexed: 12/17/2022]
Abstract
AIMS The effects of human serum albumin (HSA) complexed with various free fatty acids (FFAs) on ß-cells have not been studied in detail. In this study, we examined the effects of HSA and its mutants on FFA-induced cell viability changes and insulin secretion from the hamster pancreatic insulinoma cell line, HIT-TI5. MAIN METHODS Cells were exposed to different FFAs in the presence of HSA or its mutants and/or bovine serum albumin (BSA) for 24h. Cell viability, apoptosis, insulin secretion, and unbound FFA (FFA(u)) levels were determined. KEY FINDINGS In the presence of 0.1mM HSA, palmitate and stearate induced significant cell death at 0.1mM or higher, whereas myristate, palmitoleate, oleate, elaidate, linoleate, linoelaidate, and conjugated linoleate showed minimal changes on cell viability. Furthermore, oleate and linoleate were clearly cytoprotective against palmitate-induced cell death. The apoptosis inhibitors, cyclosporin A (csA) and the caspase inhibitor ZVAD-FMK, did not completely prevent FFA-induced cell death, although ZVAD-FMK blocked apoptosis with no differences in the presence of either HSA or BSA. In addition, insulin secretion from the cells was significantly reduced in the presence of HSA/oleate complexes. We also found differential effects of HSA mutants complexed with FFAs on cell viability. SIGNIFICANCE In summary, our results showed that saturated FFAs induced more cell death than unsaturated FFAs. Furthermore, modified HSA/FFA interactions caused by mutations of key amino acids involved in the binding of FFA to HSA resulted in changes in cell viability, suggesting a possible role of HSA polymorphism on FFA-induced changes in cellular functions.
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Sieber J, Lindenmeyer MT, Kampe K, Campbell KN, Cohen CD, Hopfer H, Mundel P, Jehle AW. Regulation of podocyte survival and endoplasmic reticulum stress by fatty acids. Am J Physiol Renal Physiol 2010; 299:F821-9. [PMID: 20668104 PMCID: PMC2957252 DOI: 10.1152/ajprenal.00196.2010] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 07/21/2010] [Indexed: 01/01/2023] Open
Abstract
Apoptosis of podocytes is considered critical in the pathogenesis of diabetic nephropathy (DN). Free fatty acids (FFAs) are critically involved in the pathogenesis of diabetes mellitus type 2, in particular the regulation of pancreatic β cell survival. The objectives of this study were to elucidate the role of palmitic acid, palmitoleic, and oleic acid in the regulation of podocyte cell death and endoplasmic reticulum (ER) stress. We show that palmitic acid increases podocyte cell death, both apoptosis and necrosis of podocytes, in a dose and time-dependent fashion. Palmitic acid induces podocyte ER stress, leading to an unfolded protein response as reflected by the induction of the ER chaperone immunoglobulin heavy chain binding protein (BiP) and proapoptotic C/EBP homologous protein (CHOP) transcription factor. Of note, the monounsaturated palmitoleic and oleic acid can attenuate the palmitic acid-induced upregulation of CHOP, thereby preventing cell death. Similarly, gene silencing of CHOP protects against palmitic acid-induced podocyte apoptosis. Our results offer a rationale for interventional studies aimed at testing whether dietary shifting of the FFA balance toward unsaturated FFAs can delay the progression of DN.
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Affiliation(s)
- Jonas Sieber
- Dept. of Biomedicine, Molecular Nephrology, Univ. Hospital Basel, Hebelstrasse 20, 4031 Basel, Switzerland
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Yang J, Chi Y, Burkhardt BR, Guan Y, Wolf BA. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells. Nutr Rev 2010; 68:270-9. [PMID: 20500788 DOI: 10.1111/j.1753-4887.2010.00282.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Leucine, a branched-chain amino acid that must be supplied in the daily diet, plays an important role in controlling protein synthesis and regulating cell metabolism in various cell types. In pancreatic beta cells, leucine acutely stimulates insulin secretion by serving as both metabolic fuel and allosteric activator of glutamate dehydrogenase to enhance glutaminolysis. Leucine has also been shown to regulate gene transcription and protein synthesis in pancreatic islet beta cells via both mTOR-dependent and -independent pathways at physiological concentrations. Long-term treatment with leucine has been shown to improve insulin secretory dysfunction of human diabetic islets via upregulation of certain key metabolic genes. In vivo, leucine administration improves glycemic control in humans and rodents with type 2 diabetes. This review summarizes and discusses the recent findings regarding the effects of leucine metabolism on pancreatic beta-cell function.
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Affiliation(s)
- Jichun Yang
- Department of Physiology and Pathophysiology, Peking University Diabetes Center, Peking University Health Science Center, Beijing, China.
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Levetan C. Distinctions between islet neogenesis and β-cell replication: implications for reversal of Type 1 and 2 diabetes. J Diabetes 2010; 2:76-84. [PMID: 20923488 DOI: 10.1111/j.1753-0407.2010.00074.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The terms "islet" and "β-cell" are often used interchangeably, yet islets are highly complex multicellular organelles that contain the insulin-producing β-cells and four other cells types, all of which play a role in maintaining glucose homeostasis within a very narrow range. Although the formation of new islets in adults is rare, occurring primarily in response to pancreatic injury and major stress to the pancreas, β-cell replication from existing cells occurs throughout adulthood. An understanding of the regulatory factors controlling pancreatic development has more clearly defined the differences between new islet formation from progenitor cells located throughout the adult pancreas and β-cell replication occurring within existing islets. The present review sets forth to more clearly distinguish the differences between the postnatal pathways of islet neogenesis and β-cell replication with a discussion of the potential implications for reversal of Type 1 and 2 diabetic patients using islet neogenesis agents that are now in development. For Type 1 diabetic patients, an immune tolerance agent in conjunction with an islet neogenesis agent may allow achievement of adequate islet mass, perhaps with subsequent potential to withdraw medications. For Type 2 diabetic patients, lifestyle changes and/or medications may sustain the production of new islets and limit the accelerated β-cell apoptosis characteristic of the condition.
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Affiliation(s)
- Claresa Levetan
- Division of Endocrinology, Chestnut Hill Hospital, Philadelphia, Pennsylvania, USA.
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Post-prandial lipid metabolism, lipid-modulating agents and cerebrovascular integrity: implications for dementia risk. ATHEROSCLEROSIS SUPP 2010; 11:49-54. [PMID: 20430703 DOI: 10.1016/j.atherosclerosissup.2010.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 04/08/2010] [Accepted: 04/08/2010] [Indexed: 10/19/2022]
Abstract
Amyloid-β (Aβ) is secreted as an apolipoprotein of nascent triglyceride-rich lipoproteins (TRL) derived from both liver and intestine, but is better recognized as the principal protein component of senile plaque in subjects with Alzheimer's disease. Recent studies suggest that exaggerated exposure to plasma Aβ can compromise cerebrovascular integrity, resulting thereafter in blood to brain delivery of plasma proteins including TRL-Aβ. Parenchymal deposits of Aβ show significant immunoreactivity to apolipoprotein B (apo B), consistent with the notion of lipoprotein-Aβ entrapment. In wild type mice chronically fed physiologically relevant diets, saturated fats (SFA) enhance chylomicron-Aβ concomitant with disturbances in blood-brain barrier integrity. Similarly, dietary cholesterol promotes cerebrovascular extravasation of apo B lipoprotein-Aβ. In this study, we investigated the effects of atorvastatin, pravastatin and probucol on dietary-fat induced disturbances in BBB function. Atorvastatin, a lipid soluble HMG-CoA reductase inhibitor prevented SFA induced parenchymal extravasation of apo B-Aβ at 28 days when incorporated into the diet at 20 mg/kg. In contrast, pravastatin a water soluble agent had no effect on BBB integrity at an equivalent dose. In cholesterol supplemented mice, probucol maintained BBB function and extravasation of apo B-Aβ was not evident. The findings suggest that some lipid-modulating agents may be effective in ameliorating the negative effects of saturated fats and cholesterol on cerebrovascular integrity.
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Current world literature. Curr Opin Endocrinol Diabetes Obes 2010; 17:177-85. [PMID: 20190584 DOI: 10.1097/med.0b013e3283382286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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López S, Bermúdez B, Abia R, Muriana FJG. The influence of major dietary fatty acids on insulin secretion and action. Curr Opin Lipidol 2010; 21:15-20. [PMID: 19915461 DOI: 10.1097/mol.0b013e3283346d39] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE OF REVIEW To briefly summarize recent advances towards understanding the influence of major dietary fatty acids on beta-cell function and evaluate their implications for insulin resistance. RECENT FINDINGS Studies in humans have shown that beta-cell function and insulin sensitivity improve progressively in the postprandial period as the proportion of monounsaturated fatty acids (MUFAs) with respect to saturated fatty acids (SFAs) in dietary fats increases. However, cell-culture experiments have revealed a dichotomy in the ability of fatty acids to moderate hyperactivity of, and induce lipotoxicity in, beta-cells. There are also some novel findings regarding the ability of HDL to protect beta-cells against oxidized LDL-induced apoptosis in vitro and of reconstituted HDL to attenuate insulin resistance in vivo. These findings raise new questions regarding the contribution of dietary fatty acids to insulin secretion and action. SUMMARY These new findings point to a critical role for major dietary fatty acids in the etiology and pathogenesis of diabetes, which appears to be of particular relevance during postprandial periods and mainly depends on the fatty acid type. This underscores the importance of dietary fatty acids in standard diabetes management.
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Affiliation(s)
- Sergio López
- Cellular and Molecular Nutrition, Instituto de la Grasa (CSIC), Seville, Spain
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Dietary fats, cerebrovasculature integrity and Alzheimer's disease risk. Prog Lipid Res 2009; 49:159-70. [PMID: 19896503 DOI: 10.1016/j.plipres.2009.10.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 10/30/2009] [Accepted: 10/30/2009] [Indexed: 01/08/2023]
Abstract
An emerging body of evidence is consistent with the hypothesis that dietary fats influence Alzheimer's disease (AD) risk, but less clear is the mechanisms by which this occurs. Alzheimer's is an inflammatory disorder, many consider in response to fibrillar formation and extracellular deposition of amyloid-beta (Abeta). Alternatively, amyloidosis could notionally be a secondary phenomenon to inflammation, because some studies suggest that cerebrovascular disturbances precede amyloid plaque formation. Hence, dietary fats may influence AD risk by either modulating Abeta metabolism, or via Abeta independent pathways. This review explores these two possibilities taking into consideration; (i) the substantial affinity of Abeta for lipids and its ordinary metabolism as an apolipoprotein; (ii) evidence that Abeta has potent vasoactive properties and (iii) studies which show that dietary fats modulate Abeta biogenesis and secretion. We discuss accumulating evidence that dietary fats significantly influence cerebrovascular integrity and as a consequence altered Abeta kinetics across the blood-brain barrier (BBB). Specifically, chronic ingestion of saturated fats or cholesterol appears to results in BBB dysfunction and exaggerated delivery from blood-to-brain of peripheral Abeta associated with lipoproteins of intestinal and hepatic origin. Interestingly, the pattern of saturated fat/cholesterol induced cerebrovascular disturbances in otherwise normal wild-type animal strains is analogous to established models of AD genetically modified to overproduce Abeta, consistent with a causal association. Saturated fats and cholesterol may exacerbate Abeta induced cerebrovascular disturbances by enhancing exposure of vessels of circulating Abeta. However, presently there is no evidence to support this contention. Rather, SFA and cholesterol appear to more broadly compromise BBB integrity with the consequence of plasma protein leakage into brain, including lipoprotein associated Abeta. The latter findings are consistent with the concept that AD is a dietary-fat induced phenotype of vascular dementia, reflecting the extraordinary entrapment of peripherally derived lipoproteins endogenously enriched in Abeta. Rather than being the initiating trigger for inflammation in AD, accumulation of extracellular lipoprotein-Abeta may be a secondary amplifier of dietary induced inflammation, or possibly, simply be consequential. Clearly, delineating the mechanisms by which dietary fats increase AD risk may be informative in developing new strategies for prevention and treatment of AD.
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Differential effects of dietary fatty acids on the cerebral distribution of plasma-derived apo B lipoproteins with amyloid-beta. Br J Nutr 2009; 103:652-62. [PMID: 19860996 DOI: 10.1017/s0007114509992194] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Some dietary fats are a risk factor for Alzheimer's disease (AD) but the mechanisms for this association are presently unknown. In the present study we showed in wild-type mice that chronic ingestion of SFA results in blood-brain barrier (BBB) dysfunction and significant delivery into the brain of plasma proteins, including apo B lipoproteins that are endogenously enriched in amyloid-beta (Abeta). Conversely, the plasma concentration of S100B was used as a marker of brain-to-blood leakage and was found to be increased two-fold because of SFA feeding. Consistent with a deterioration in BBB integrity in SFA-fed mice was a diminished cerebrovascular expression of occludin, an endothelial tight junction protein. In contrast to SFA-fed mice, chronic ingestion of MUFA or PUFA had no detrimental effect on BBB integrity. Utilising highly sensitive three-dimensional immunomicroscopy, we also showed that the cerebral distribution and co-localisation of Abeta with apo B lipoproteins in SFA-fed mice are similar to those found in amyloid precursor protein/presenilin-1 (APP/PS1) amyloid transgenic mice, an established murine model of AD. Moreover, there was a strong positive association of plasma-derived apo B lipoproteins with cerebral Abeta deposits. Collectively, the findings of the present study provide a plausible explanation of how dietary fats may influence AD risk. Ingestion of SFA could enhance peripheral delivery to the brain of circulating lipoprotein-Abeta and exacerbate the amyloidogenic cascade.
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Morgan NG, Dhayal S. G-protein coupled receptors mediating long chain fatty acid signalling in the pancreatic beta-cell. Biochem Pharmacol 2009; 78:1419-27. [PMID: 19660440 DOI: 10.1016/j.bcp.2009.07.020] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/27/2009] [Accepted: 07/27/2009] [Indexed: 11/16/2022]
Abstract
It is increasingly clear that some of the effects of both free and derivatised long chain fatty acids in pancreatic beta-cells are mediated by a group of G-protein coupled receptors. Some of these display close structural homology while others are more divergent. This Commentary reviews the expression and functional roles of three such molecules, GPR40, GPR119 and GPR120. GPR40 is the best characterised of this group and appears to mediate the acute stimulatory effects of long chain fatty acids on insulin secretion. GPR40 has also been proposed as a potential mediator of fatty acid toxicity but this is more controversial. GPR119 is also involved in stimulation of insulin secretion and responds primarily to ethanolamide derivatives of long chain fatty acids and also to some lysophospholipids rather than to free fatty acids. It may represent a useful target for the development of new insulin secretagogues aimed to enhance insulin release in patients with type 2 diabetes. GPR120 is the most enigmatic of the lipid-responsive cell-surface receptors and its function remains to be established. It has been proposed to play a cytoprotective role in certain other cell types but it is unclear whether it fulfils a similar function in beta-cells.
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Affiliation(s)
- Noel G Morgan
- Institute of Biomedical & Clinical Science, John Bull Building, Peninsula Medical School, Plymouth PL6 8BU, UK.
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