101
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Mitrofanova A, Mallela SK, Ducasa GM, Yoo TH, Rosenfeld-Gur E, Zelnik ID, Molina J, Varona Santos J, Ge M, Sloan A, Kim JJ, Pedigo C, Bryn J, Volosenco I, Faul C, Zeidan YH, Garcia Hernandez C, Mendez AJ, Leibiger I, Burke GW, Futerman AH, Barisoni L, Ishimoto Y, Inagi R, Merscher S, Fornoni A. SMPDL3b modulates insulin receptor signaling in diabetic kidney disease. Nat Commun 2019; 10:2692. [PMID: 31217420 PMCID: PMC6584700 DOI: 10.1038/s41467-019-10584-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 05/15/2019] [Indexed: 12/22/2022] Open
Abstract
Sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) is a lipid raft enzyme that regulates plasma membrane (PM) fluidity. Here we report that SMPDL3b excess, as observed in podocytes in diabetic kidney disease (DKD), impairs insulin receptor isoform B-dependent pro-survival insulin signaling by interfering with insulin receptor isoforms binding to caveolin-1 in the PM. SMPDL3b excess affects the production of active sphingolipids resulting in decreased ceramide-1-phosphate (C1P) content as observed in human podocytes in vitro and in kidney cortexes of diabetic db/db mice in vivo. Podocyte-specific Smpdl3b deficiency in db/db mice is sufficient to restore kidney cortex C1P content and to protect from DKD. Exogenous administration of C1P restores IR signaling in vitro and prevents established DKD progression in vivo. Taken together, we identify SMPDL3b as a modulator of insulin signaling and demonstrate that supplementation with exogenous C1P may represent a lipid therapeutic strategy to treat diabetic complications such as DKD.
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Affiliation(s)
- A Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - S K Mallela
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - G M Ducasa
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - T H Yoo
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, 03722, Korea
| | - E Rosenfeld-Gur
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - I D Zelnik
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - J Molina
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - J Varona Santos
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - M Ge
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - A Sloan
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - J J Kim
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - C Pedigo
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Internal Medicine, Yale University School of Medicine, New Haven, 06510, CT, USA
| | - J Bryn
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - I Volosenco
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Lewis Gale Medical Center, Salem, 24153, VI, USA
| | - C Faul
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, 35233, AL, USA
| | - Y H Zeidan
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Radiation Oncology, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Radiation Oncology, American University of Beirut, Beirut, 1107 2020, Lebanon
| | - C Garcia Hernandez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Department of Radiation Oncology, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - A J Mendez
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - I Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, 17176, Sweden
| | - G W Burke
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - A H Futerman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - L Barisoni
- Department of Pathology, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - Y Ishimoto
- Division of Nephrology and Endocrinology, University of Tokyo Graduate School of Medicine, Tokyo, 113-8654, Japan
- Division of CKD Pathophysiology, University of Tokyo Graduate School of Medicine, Tokyo, 113-8654, Japan
| | - R Inagi
- Division of Nephrology and Endocrinology, University of Tokyo Graduate School of Medicine, Tokyo, 113-8654, Japan
- Division of CKD Pathophysiology, University of Tokyo Graduate School of Medicine, Tokyo, 113-8654, Japan
| | - S Merscher
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA
| | - A Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA.
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, 33136, FL, USA.
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102
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Chew WS, Torta F, Ji S, Choi H, Begum H, Sim X, Khoo CM, Khoo EYH, Ong WY, Van Dam RM, Wenk MR, Tai ES, Herr DR. Large-scale lipidomics identifies associations between plasma sphingolipids and T2DM incidence. JCI Insight 2019; 5:126925. [PMID: 31162145 DOI: 10.1172/jci.insight.126925] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Sphingolipids (SPs) are ubiquitous, structurally diverse molecules that include ceramides, sphingomyelins, and sphingosines. They are involved in various pathologies including obesity and type 2 diabetes mellitus (T2DM). Therefore, it is likely that perturbations in plasma concentrations of SPs are associated with disease. Identifying these associations may reveal useful biomarkers or provide insight into disease processes. METHODS We performed a lipidomics evaluation of molecularly-distinct SPs in the plasma of 2,302 ethnically-Chinese Singaporeans using electrospray ionization mass spectrometry coupled with liquid chromatography. SP profiles were compared to clinical and biochemical characteristics, and subjects were evaluated by follow-up visits for 11 years. RESULTS We found that ceramides correlate positively but hexosylceramides correlate negatively with body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR). Furthermore, SPs with a d16:1 sphingoid backbone correlate more positively with BMI and HOMA-IR, while d18:2 SPs correlate less positively, relative to canonical d18:1 SPs. We also found that higher concentrations of two distinct sphingomyelins were associated with a higher risk of T2DM (HR 1.45, 95% CI 1.18-1.78 for SM d16:1/C18:0; and HR 1.40, 95% CI 1.17-1.68 for SM d18:1/C18:0). CONCLUSION We identified significant associations between SPs and obesity/T2DM characteristics, specifically, that of hexosylceramides, d16:1 SPs, and d18:2 SPs. This suggests that the balance of SP metabolism, rather than ceramide accumulation, is associated with the pathology of obesity. We further identified two specific SPs that may represent prognostic biomarkers for T2DM. FUNDING Funding sources are listed in the Acknowledgements section.
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Affiliation(s)
| | - Federico Torta
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore
| | - Shanshan Ji
- Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore
| | - Hyungwon Choi
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National Health System, Singapore.,Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research, Singapore
| | - Husna Begum
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore
| | - Xueling Sim
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore
| | - Chin Meng Khoo
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National Health System, Singapore
| | - Eric Yin Hao Khoo
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National Health System, Singapore
| | - Wei-Yi Ong
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Rob M Van Dam
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National Health System, Singapore
| | - Markus R Wenk
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Singapore Lipidomics Incubator, Life Sciences Institute, National University of Singapore, Singapore
| | - E Shyong Tai
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore and National Health System, Singapore.,Duke-NUS Graduate Medical School, Singapore
| | - Deron R Herr
- Department of Pharmacology and.,Department of Biology, San Diego State University, San Diego, California, USA
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103
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Teng W, Li Y, Du M, Lei X, Xie S, Ren F. Sulforaphane Prevents Hepatic Insulin Resistance by Blocking Serine Palmitoyltransferase 3-Mediated Ceramide Biosynthesis. Nutrients 2019; 11:E1185. [PMID: 31137828 PMCID: PMC6566605 DOI: 10.3390/nu11051185] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/20/2022] Open
Abstract
Sulforaphane (SFA), a naturally active isothiocyanate compound from cruciferous vegetables used in clinical trials for cancer treatment, was found to possess potency to alleviate insulin resistance. But its underlying molecular mechanisms are still incompletely understood. In this study, we assessed whether SFA could improve insulin sensitivity and glucose homeostasis both in vitro and in vivo by regulating ceramide production. The effects of SFA on glucose metabolism and expression levels of key proteins in the hepatic insulin signaling pathway were evaluated in insulin-resistant human hepatic carcinoma HepG2 cells. The results showed that SFA dose-dependently increased glucose uptake and intracellular glycogen content by regulating the insulin receptor substrate 1 (IRS-1)/protein kinase B (Akt) signaling pathway in insulin-resistant HepG2 cells. SFA also reduced ceramide contents and downregulated transcription of ceramide-related genes. In addition, knockdown of serine palmitoyltransferase 3 (SPTLC3) in HepG2 cells prevented ceramide accumulation and alleviated insulin resistance. Moreover, SFA treatment improved glucose tolerance and insulin sensitivity, inhibited SPTLC3 expression and hepatic ceramide production and reduced hepatic triglyceride content in vivo. We conclude that SFA recovers glucose homeostasis and improves insulin sensitivity by blocking ceramide biosynthesis through modulating SPTLC3, indicating that SFA may be a potential candidate for prevention and amelioration of hepatic insulin resistance via a ceramide-dependent mechanism.
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Affiliation(s)
- Wendi Teng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Yuan Li
- Key Laboratory of Functional Dairy, Co-constructed by ministry of Education and Beijing Municipality, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Min Du
- Department of Animal Sciences, Washington State University, Pullman, WA 99164, USA.
| | - Xingen Lei
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
| | - Siyu Xie
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Fazheng Ren
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
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104
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Sergi D, Naumovski N, Heilbronn LK, Abeywardena M, O'Callaghan N, Lionetti L, Luscombe-Marsh N. Mitochondrial (Dys)function and Insulin Resistance: From Pathophysiological Molecular Mechanisms to the Impact of Diet. Front Physiol 2019; 10:532. [PMID: 31130874 PMCID: PMC6510277 DOI: 10.3389/fphys.2019.00532] [Citation(s) in RCA: 185] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/15/2019] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial dysfunction has been implicated in the pathogenesis of insulin resistance, the hallmark of type 2 diabetes mellitus (T2DM). However, the cause-effect relationship remains to be fully elucidated. Compelling evidence suggests that boosting mitochondrial function may represent a valuable therapeutic tool to improve insulin sensitivity. Mitochondria are highly dynamic organelles, which adapt to short- and long-term metabolic perturbations by undergoing fusion and fission cycles, spatial rearrangement of the electron transport chain complexes into supercomplexes and biogenesis governed by peroxisome proliferator-activated receptor γ co-activator 1α (PGC 1α). However, these processes appear to be dysregulated in type 2 diabetic individuals. Herein, we describe the mechanistic link between mitochondrial dysfunction and insulin resistance in skeletal muscle alongside the intracellular pathways orchestrating mitochondrial bioenergetics. We then review current evidence on nutritional tools, including fatty acids, amino acids, caloric restriction and food bioactive derivatives, which may enhance insulin sensitivity by therapeutically targeting mitochondrial function and biogenesis.
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Affiliation(s)
- Domenico Sergi
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, SA, Australia.,Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Nenad Naumovski
- Faculty of Health, University of Canberra, Canberra, ACT, Australia.,Collaborative Research in Bioactives and Biomarkers (CRIBB) Group, Canberra, ACT, Australia
| | | | - Mahinda Abeywardena
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, SA, Australia
| | - Nathan O'Callaghan
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, SA, Australia
| | - Lillà Lionetti
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, Fisciano, Italy
| | - Natalie Luscombe-Marsh
- Nutrition and Health Substantiation Group, Nutrition and Health Program, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Adelaide, SA, Australia.,Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
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105
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De Palma RM, Parnham SR, Li Y, Oaks JJ, Peterson YK, Szulc ZM, Roth BM, Xing Y, Ogretmen B. The NMR-based characterization of the FTY720-SET complex reveals an alternative mechanism for the attenuation of the inhibitory SET-PP2A interaction. FASEB J 2019; 33:7647-7666. [PMID: 30917007 DOI: 10.1096/fj.201802264r] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The su(var)3-9, enhancer of zeste, trithorax (SET)/inhibitor 2 of protein phosphatase 2A (PP2A) oncoprotein binds and inhibits PP2A, composed of various isoforms of scaffolding, regulatory, and catalytic subunits. Targeting SET with a sphingolipid analog drug fingolimod (FTY720) or ceramide leads to the reactivation of tumor suppressor PP2A. However, molecular details of the SET-FTY720 or SET-ceramide, and mechanism of FTY720-dependent PP2A activation, remain unknown. Here, we report the first in solution examination of the SET-FTY720 or SET-ceramide complexes by NMR spectroscopy. FTY720-ceramide binding resulted in chemical shifts of residues residing at the N terminus of SET, preventing its dimerization or oligomerization. This then released SET from PP2ACα, resulting in PP2A activation, while monomeric SET remained associated with the B56γ. Our data also suggest that the PP2A holoenzyme, composed of PP2A-Aβ, PP2A-B56γ, and PP2ACα subunits, is selectively activated in response to the formation of the SET-FTY720 complex in A549 cells. Various PP2A-associated downstream effector proteins in the presence or absence of FTY720 were then identified by stable isotope labeling with amino cells in cell culture, including tumor suppressor nonmuscle myosin IIA. Attenuation of FTY720-SET association by point mutations of residues that are involved in FTY720 binding or dephosphorylation of SET at Serine 171, enhanced SET oligomerization and the formation of the SET-PP2A inhibitory complex, leading to resistance to FTY720-dependent PP2A activation.-De Palma, R. M., Parnham, S. R., Li, Y., Oaks, J. J., Peterson, Y. K., Szulc, Z. M., Roth, B. M., Xing, Y., Ogretmen, B. The NMR-based characterization of the FTY720-SET complex reveals an alternative mechanism for the attenuation of the inhibitory SET-PP2A interaction.
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Affiliation(s)
- Ryan M De Palma
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Stuart R Parnham
- Department of Biochemistry and Biophysics, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA
| | - Yitong Li
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | - Yuri K Peterson
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Zdzislaw M Szulc
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Braden M Roth
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Yongna Xing
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Besim Ogretmen
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA.,Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, USA
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106
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Preuss C, Jelenik T, Bódis K, Müssig K, Burkart V, Szendroedi J, Roden M, Markgraf DF. A New Targeted Lipidomics Approach Reveals Lipid Droplets in Liver, Muscle and Heart as a Repository for Diacylglycerol and Ceramide Species in Non-Alcoholic Fatty Liver. Cells 2019; 8:cells8030277. [PMID: 30909521 PMCID: PMC6468791 DOI: 10.3390/cells8030277] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 12/13/2022] Open
Abstract
Obesity is frequently associated with excessive accumulation of lipids in ectopic tissue and presents a major risk factor for type 2 diabetes (T2D) and non-alcoholic fatty liver disease (NAFLD). Diacylglycerols (DAGs) and ceramides (CERs) were identified as key players in lipid-induced insulin resistance, typical for such diseases. Recent results suggest that the subcellular distribution of these lipids affects their lipotoxic properties. However, the subcellular dynamics of these lipids and the role of lipid droplets (LDs) as a potential storage site is not understood. Here, we developed a liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS)-method for the rapid and simultaneous quantification of DAG and CER species in tissue sample fractions. The assay is characterized by excellent recovery of analytes, limit of quantification, accuracy and precision. We established a fractionation protocol that allows the separation of subcellular tissue fractions. This method was subsequently tested to measure the concentration of DAGs and CERs in subcellular fractions of human muscle and several mouse tissues. In a mouse model of NAFLD, application of this method revealed a prominent role for LDs as repository for lipotoxic DAG and CER species. In conclusion, the new method proved as a valuable tool to analyse the subcellular dynamics of lipotoxins, related to the pathogenesis of insulin resistance, T2D and NAFLD.
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Affiliation(s)
- Christina Preuss
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
| | - Tomas Jelenik
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
| | - Kálmán Bódis
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
| | - Karsten Müssig
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, D-40225, Düsseldorf, Germany.
| | - Volker Burkart
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
| | - Julia Szendroedi
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, D-40225, Düsseldorf, Germany.
| | - Michael Roden
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
- Division of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, D-40225, Düsseldorf, Germany.
| | - Daniel F Markgraf
- Institute for Clinical Diabetology, German Diabetes Center, c/o Auf'm Hennekamp 65, D-40225 Düsseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), München, D-85764 Neuherberg, Germany.
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107
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TNF- α Downregulation Modifies Insulin Receptor Substrate 1 (IRS-1) in Metabolic Signaling of Diabetic Insulin-Resistant Hepatocytes. Mediators Inflamm 2019; 2019:3560819. [PMID: 30863203 PMCID: PMC6378771 DOI: 10.1155/2019/3560819] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/15/2018] [Indexed: 11/30/2022] Open
Abstract
One of the major mechanisms of hyperglycemia in type 2 diabetes is insulin resistance (IR) which can induce free fatty acids like palmitate. In hepatic cell, as an insulin target tissue, insulin resistance can be stimulated by inflammatory cytokine TNF-α. The interaction of intracellular TNF-α signal with the insulin signaling pathway is not well identified. Hence, we aimed to investigate the effect of TNF-α elimination on the diabetic model of palmitate-induced insulin-resistant hepatocytes (HepG2). The changes of phosphorylation rate in IRS-1 protein are determined to know the effect of TNF-α on this key protein of the insulin signaling pathway. HepG2 cells were treated with 0.5 Mm palmitate, and TNF-α gene knockdown was performed by shRNA-mediated technique. Western blot analysis was used to evaluate the phosphorylated activity of the insulin signaling pathway. Palmitate-induced IR could increase TNF-α protein expression 1.2-, 2.78-, and 2.25-fold compared to the control cells at times of 8 h, 16 h, and 24 h, respectively. TNF-α expression in downregulated cells transfected with shRNA-TNF-α is approximately 47.0% of normal cells and 49.0% in the case of scrambled cells. IRS-1 phosphorylation in TNF-α-downregulated and stimulated cells with 100 nM insulin, after treatment and in the absence of palmitate, was 45% and 29% higher than the normal cells. These data support the evidence that TNF-α downregulation strategy contributes to the improvement of IRS-1 phosphorylation after insulin stimulation and insulin response in HepG2 liver cells.
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108
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Effects of palmitate and astaxanthin on cell viability and proinflammatory characteristics of mesenchymal stem cells. Int Immunopharmacol 2019; 68:164-170. [PMID: 30639962 DOI: 10.1016/j.intimp.2018.12.063] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/16/2018] [Accepted: 12/28/2018] [Indexed: 12/18/2022]
Abstract
Mesenchymal stem cells (MSCs) have broad immunomodulatory activities. These cells are a stable source of cytokine production such as interleukin-6 (IL6), monocyte chemoattractant protein-1 (MCP-1/CCL2) and vascular endothelial growth factor (VEGF). Fatty acid elevation in chronic metabolic diseases alters the microenvironment of MSCs and thereby, might affect their survival and cytokine production. In the present study, we investigated the effects of palmitate, the most abundant saturated free fatty acid (FFA) in plasma, and astaxanthin, a potent antioxidant, on cell viability and apoptosis in human bone marrow-driven mesenchymal stem cells. We also elucidated how palmitate and astaxanthin influence the inflammation in MSCs. Human mesenchymal stem cells were collected from an aspirate of the femurs and tibias marrow compartment. The effect of palmitate on cell viability, caspase activity and pro-inflammatory cytokines expression and secretion were evaluated. In addition, activation of the MAP kinases and NF-kB signaling pathways were investigated. The results showed that astaxanthin protected MSCs from palmitate-induced cell death. We found that palmitate significantly enhanced IL-6, VEGF and MCP-1 expression, and secretion in MSC cells. Increased cytokine expression was parallel to the enhanced phosphorylation of P38, ERK and IKKα-IKKβ. In addition, pretreatment with JNK, ERK, P38, and NF-kB inhibitors could correspondingly attenuate palmitate-induced expression of VEGF, IL-6, and MCP-1. Our results demonstrated that fatty acid exposure causes inflammatory responses in MSCs that can be alleviated favorably by astaxanthin treatment.
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Turpin-Nolan SM, Hammerschmidt P, Chen W, Jais A, Timper K, Awazawa M, Brodesser S, Brüning JC. CerS1-Derived C18:0 Ceramide in Skeletal Muscle Promotes Obesity-Induced Insulin Resistance. Cell Rep 2019; 26:1-10.e7. [DOI: 10.1016/j.celrep.2018.12.031] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 10/16/2018] [Accepted: 12/05/2018] [Indexed: 12/24/2022] Open
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Sokolowska E, Blachnio-Zabielska A. The Role of Ceramides in Insulin Resistance. Front Endocrinol (Lausanne) 2019; 10:577. [PMID: 31496996 PMCID: PMC6712072 DOI: 10.3389/fendo.2019.00577] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 08/07/2019] [Indexed: 12/29/2022] Open
Abstract
Resistance to insulin is a pathophysiological state related to the decreased response of peripheral tissues to the insulin action, hyperinsulinemia and raised blood glucose levels caused by increased hepatic glucose outflow. All the above precede the onset of full-blown type 2 diabetes. According to the World Health Organization (WHO), in 2016 more than 1.9 billion people over 18 years of age were overweight and about 600 million were obese. Currently, the primary hypothesis explaining the probability of occurrence of insulin resistance assigns a fundamental role of lipids accumulation in adipocytes or nonadipose tissue (muscle, liver) and the locally developing chronic inflammation caused by adipocytes hypertrophy. However, the major molecular pathways are unknown. The sphingolipid ceramide is the main culprit that combines a plethora of nutrients (e.g., saturated fatty acids) and inflammatory cytokines (e.g., TNFα) to the progression of insulin resistance. The accumulation of sphingolipid ceramide in tissues of obese humans, rodents and Western-diet non-human primates is in line with diabetes, hypertension, cardiac failure or atherosclerosis. In hypertrophied adipose tissue, after adipocytes excel their storage capacity, neutral lipids begin to accumulate in nonadipose tissues, inducing organ dysfunction. Furthermore, obesity is closely related to the development of chronic inflammation and the release of cytokines directly from adipocytes or from macrophages that infiltrate adipose tissue. Enzymes taking part in ceramide metabolism are potential therapeutic targets to manipulate sphingolipids content in tissues, either by inhibition of their synthesis or through stimulation of ceramides degradation. In this review, we will evaluate the mechanisms responsible for the development of insulin resistance and possible therapeutic perspectives.
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Ardah MT, Parween S, Varghese DS, Emerald BS, Ansari SA. Saturated fatty acid alters embryonic cortical neurogenesis through modulation of gene expression in neural stem cells. J Nutr Biochem 2018; 62:230-246. [DOI: 10.1016/j.jnutbio.2018.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/30/2018] [Accepted: 09/17/2018] [Indexed: 12/16/2022]
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Charytoniuk T, Iłowska N, Berk K, Drygalski K, Chabowski A, Konstantynowicz-Nowicka K. The effect of enterolactone on sphingolipid pathway and hepatic insulin resistance development in HepG2 cells. Life Sci 2018; 217:1-7. [PMID: 30468835 DOI: 10.1016/j.lfs.2018.11.044] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 11/25/2022]
Abstract
AIMS Obesity and type 2 diabetes mellitus, correlate with increased tissue concentration of sphingolipids, which directly interfere with insulin signaling pathway. Phytoestrogens are a group of plant-derived compounds that have been studied in the case of metabolic disorders treatment. Therefore, the aim of this study was to ascertain whether enterolactone (ENL), a commonly known phytoestrogen, may affect sphingolipid metabolism and decrease hepatic insulin resistance development in a lipid overload state. MAIN METHODS The study was conducted on HepG2 cells incubated with ENL and/or palmitic acid (PA) for 16 h. Intra- and extracellular sphingolipid concentrations were assessed by high performance liquid chromatography. The expression of sphingolipid pathway enzymes, apoptosis and insulin signaling pathway proteins and glucose metabolism regulators were evaluated by Western Blot. KEY FINDINGS In HepG2 cells, a considerable augmentation of intracellular ceramide and sphingosine concentration in ENL with PA group were indicated with simultaneous increase in extracellular ceramide concentration. The ENL treatment increased expression of selected enzymes from de novo ceramide synthesis pathway with lower expression of ceramide transfer protein. We also observed a decreased expression of insulin-stimulated phosphorylation of AKT and AMPK after exposure to ENL with PA. Our research demonstrated that ENL with PA resulted in an increased expression of caspase-3. SIGNIFICANCE Enterolactone, in a higher fatty acids availability, led to the development of hepatic IR in HepG2 cells. This phenomenon may be the result of elevated intracellular ceramide accumulation caused by increased de novo synthesis pathway what led to enhanced apoptosis of HepG2 cells.
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Affiliation(s)
- Tomasz Charytoniuk
- Department of Physiology, Medical University of Bialystok, Mickiewicza St. 2C, 15-222 Bialystok, Poland
| | - Nicoletta Iłowska
- Department of Physiology, Medical University of Bialystok, Mickiewicza St. 2C, 15-222 Bialystok, Poland
| | - Klaudia Berk
- Department of Physiology, Medical University of Bialystok, Mickiewicza St. 2C, 15-222 Bialystok, Poland
| | - Krzysztof Drygalski
- Department of Physiology, Medical University of Bialystok, Mickiewicza St. 2C, 15-222 Bialystok, Poland
| | - Adrian Chabowski
- Department of Physiology, Medical University of Bialystok, Mickiewicza St. 2C, 15-222 Bialystok, Poland
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Descorbeth M, Figueroa K, Serrano-Illán M, De León M. Protective effect of docosahexaenoic acid on lipotoxicity-mediated cell death in Schwann cells: Implication of PI3K/AKT and mTORC2 pathways. Brain Behav 2018; 8:e01123. [PMID: 30264903 PMCID: PMC6236228 DOI: 10.1002/brb3.1123] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 08/07/2018] [Accepted: 08/14/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND AIM Docosahexaenoic acid (DHA) exhibits neuroprotective properties and has been shown to preserve nerve cells following trauma and ischemic injury. Recently, we showed that DHA pretreatment improved locomotion and reduced neuropathic pain after acute spinal cord injury in adult rats. These improvements were associated with an increase in the levels of AKT in spinal cord injury neurons. In this study, we investigate the implication of PI3K/AKT and mTOR pathway in DHA-mediated protection of primary cultured Schwann cells (pSC) undergoing palmitic acid-induced lipotoxicity (PA-LTx). METHODS Primary cultured Schwann cells were treated with PA (PA:BSA, 2:1) in the presence or absence of DHA (1-200 µM) for 24-48 hr. Cell viability was determined by crystal violet staining and nuclear morphology was examined using Hoechst staining. RESULTS We found that pSC cultures exposed to palmitic acid (PA) overload showed chromatin condensation, a decrease in cell viability and an inhibition of AKT phosphorylation in a time-dependent manner. Next, pSC exposed to PA overload were treated with DHA. The data show that co-treatment with DHA inhibited the loss of cell viability and apoptosis caused by PA. Moreover, treatment with DHA inhibited chromatin condensation, significantly stimulated p-AKT phosphorylation under PA-LTx condition, and DHA alone increased AKT phosphorylation. Additionally, when these pSC cultures were treated with PI3K inhibitors LY294002 and, BKM120 and mTOR inhibitors Torin 1 (mTORC1/mTORC2), but not rapamycin (mTORC1), the protective effects of DHA were not observed. CONCLUSION These findings suggest PI3K/AKT and mTORC2 kinase pathways are involved in the protective function (s) of DHA in PA-induced Schwann cell death.
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Affiliation(s)
- Magda Descorbeth
- Center for Health Disparities and Molecular Medicine and Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Karen Figueroa
- Center for Health Disparities and Molecular Medicine and Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Miguel Serrano-Illán
- Center for Health Disparities and Molecular Medicine and Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | - Marino De León
- Center for Health Disparities and Molecular Medicine and Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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Ardah MT, Parween S, Varghese DS, Emerald BS, Ansari SA. Saturated fatty acid regulated lncRNA dataset during in vitro human embryonic neurogenesis. Data Brief 2018; 21:1061-1065. [PMID: 30450400 PMCID: PMC6226592 DOI: 10.1016/j.dib.2018.10.101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/18/2018] [Accepted: 10/22/2018] [Indexed: 01/02/2023] Open
Abstract
Human embryonic stem cells (hESCs) were used as a model of embryonic neurogenesis to identify the effect of excess fat uptake on neurodevelopment (Ardah et al., 2018). Herein, by directed differentiation of hESCs into neurons using established protocols, this data was generated for expression profiles of select lncRNAs during in vitro embryonic neurogenesis and their differential expression due to excess fat (palmitate) uptake. The undifferentiated hESCs were treated with 250 µM palmitate after identifying it as the highest concentration which is non-toxic to these cells. The palmitate treated hESCs were differentiated towards neurons keeping the levels of palmitate consistent throughout the differentiation process and fat uptake was confirmed by Oil Red O staining. The expression analysis of lncRNAs was performed by RT-qPCR on vehicle control and palmitate treated cells from 4 stages of differentiation, D0 (undifferentiated hESCs), D12 (neural stem cells), D44 (neural progenitors) and D70 (neurons) using lncRNAs array plates from Arraystar Inc. which contains 372 functionally identified lncRNAs found to be associated with lipid metabolism and other pathways (Cat# AS-NR-004).
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Affiliation(s)
- Mustafa T Ardah
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Shama Parween
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Divya S Varghese
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
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GPRC5B-Mediated Sphingomyelin Synthase 2 Phosphorylation Plays a Critical Role in Insulin Resistance. iScience 2018; 8:250-266. [PMID: 30343189 PMCID: PMC6197706 DOI: 10.1016/j.isci.2018.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/09/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022] Open
Abstract
GPRC5B recruitment of Src family kinases has been implicated in diet-induced insulin resistance. However, the mechanism of this action is not fully understood. Here, we report that GPRC5B-mediated phosphorylation of sphingomyelin synthase 2 (SMS2) by Fyn is a crucial step in the development of insulin resistance. Lipid-induced metabolic stress augments SMS2 phosphorylation by facilitating the interaction of GPRC5B and SMS2. SMS2 phosphorylation reduces its ubiquitination, and consequently increases SMS2 protein abundance. Although ceramide and diacylglycerol (DAG) have been known to be central mediators of lipid-induced insulin resistance, the accumulation of these lipids fails to impair insulin signaling in SMS2 knockout mouse embryonic fibroblasts (MEFs). Conversely, exogenous expression of a phosphomimetic SMS2 impairs insulin action in SMS2 knockout MEFs under metabolic stress conditions. We demonstrate that SMS2-generated DAG in sphingomyelin synthesis inhibits insulin signaling through JNK activation. Thus, GPRC5B links sphingolipid metabolism to diet-induced insulin resistance via SMS2-dependent DAG production. Saturated fatty acids enhance interaction between GPRC5B and SMS2 GPRC5B facilitates tyrosine phosphorylation of SMS2 by recruiting Fyn Tyrosine phosphorylation of SMS2 increases its protein abundance SMS2-generated DAG is critical for the development of insulin resistance
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Kutoh E, Wada A, Hayashi J. REGULATION OF FREE FATTY ACID BY SITAGLIPTIN MONOTHERAPY IN DRUG-NAÏVE SUBJECTS WITH TYPE 2 DIABETES. Endocr Pract 2018; 24:1063-1072. [PMID: 30289315 DOI: 10.4158/ep-2018-0287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the effects of sitagliptin on the regulation of free fatty acid (FFA) and other metabolic parameters in drug-naïve subjects with type 2 diabetes mellitus (T2DM). METHODS This was a prospective, nonrandomized, observational study. Drug-naïve subjects with T2DM received 25 to 50 mg/day sitagliptin monotherapy (n = 64). At 3 months, FFA and other metabolic parameters were compared with those at baseline. FFA was measured by colorimetry with enzymatic reactions. As a comparator, 12.5 to 25 mg/day alogliptin monotherapy was given to drug-naïve subjects with T2DM (n = 55). RESULTS Significant reductions in FFA (-13.2%, P<0.01) levels were observed with sitagliptin but not alogliptin. Both drugs showed similar glycemic efficacies. Significant correlations were observed between the changes (Δ) of FFA and Δglycated hemoglobin A1c (HbA1c), Dtotal cholesterol (TC), Δnon-high-density lipoprotein cholesterol (HDL-C), or Δlow-density lipoprotein cholesterol (LDL-C), and significant negative correlations were seen between ΔFFA and Δhomeostasis model assessment-B (HOMA-B), ΔC-peptide immunoreactivity (CPR)-index or Δbody mass index (BMI) in the sitagliptin group. The subjects in the sitagliptin group were further divided into 2 subgroups (n = 32 each) according to the changes of FFA (group B [above the median] ΔFFA = 23.1 %, P<.0005; group A [below the median] ΔFFA = -37.3 %, P<.00001). At baseline, FFA levels were significantly higher in group A versus group B ( P<.001). Higher degrees of reductions of FBG (-14.6% vs. -9.3%, P<0.05) or HbA1c (-20.6% vs. -16.9%, P<.05), and increases of HOMA-B (52.7% vs. 38.3%, P<.03) or CPR-index (37.5% vs. 18.8%, P<.02) were observed in group A versus group B. Significant reductions of TC (-5.8%, P<.002), non-HDL-C (-7.8%, P<.001) or LDL-C (-6.3%, P<.02), and significant increases of C-peptide (11.3%, P<.05) were seen only in group A. CONCLUSION Sitagliptin could downregulate high FFA levels. Subjects with reductions of FFA levels had better glycemic efficacies and higher degrees of enhancement of beta-cell function than others. Reductions of atherogenic cholesterols were seen in these populations. ABBREVIATIONS CPR = C-peptide immunoreactivity; DPP-4 = dipeptidyl peptidase 4; FBG = fasting blood glucose; FFA = free fatty acid; HbA1c = glycated hemoglobin A1c; HDL-C = high-density lipoprotein cholesterol; HOMA-R = homeostasis model assessment-R; HOMA-B = homeostasis model assessment-B; non-HDL-C = non-HDL-cholesterol; LDL-C = low-density lipoprotein cholesterol; TC = total cholesterol; T2DM = type 2 diabetes; TG = triglyceride; UA = uric acid.
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Petersen MC, Shulman GI. Mechanisms of Insulin Action and Insulin Resistance. Physiol Rev 2018; 98:2133-2223. [PMID: 30067154 PMCID: PMC6170977 DOI: 10.1152/physrev.00063.2017] [Citation(s) in RCA: 1338] [Impact Index Per Article: 223.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 12/15/2022] Open
Abstract
The 1921 discovery of insulin was a Big Bang from which a vast and expanding universe of research into insulin action and resistance has issued. In the intervening century, some discoveries have matured, coalescing into solid and fertile ground for clinical application; others remain incompletely investigated and scientifically controversial. Here, we attempt to synthesize this work to guide further mechanistic investigation and to inform the development of novel therapies for type 2 diabetes (T2D). The rational development of such therapies necessitates detailed knowledge of one of the key pathophysiological processes involved in T2D: insulin resistance. Understanding insulin resistance, in turn, requires knowledge of normal insulin action. In this review, both the physiology of insulin action and the pathophysiology of insulin resistance are described, focusing on three key insulin target tissues: skeletal muscle, liver, and white adipose tissue. We aim to develop an integrated physiological perspective, placing the intricate signaling effectors that carry out the cell-autonomous response to insulin in the context of the tissue-specific functions that generate the coordinated organismal response. First, in section II, the effectors and effects of direct, cell-autonomous insulin action in muscle, liver, and white adipose tissue are reviewed, beginning at the insulin receptor and working downstream. Section III considers the critical and underappreciated role of tissue crosstalk in whole body insulin action, especially the essential interaction between adipose lipolysis and hepatic gluconeogenesis. The pathophysiology of insulin resistance is then described in section IV. Special attention is given to which signaling pathways and functions become insulin resistant in the setting of chronic overnutrition, and an alternative explanation for the phenomenon of ‟selective hepatic insulin resistanceˮ is presented. Sections V, VI, and VII critically examine the evidence for and against several putative mediators of insulin resistance. Section V reviews work linking the bioactive lipids diacylglycerol, ceramide, and acylcarnitine to insulin resistance; section VI considers the impact of nutrient stresses in the endoplasmic reticulum and mitochondria on insulin resistance; and section VII discusses non-cell autonomous factors proposed to induce insulin resistance, including inflammatory mediators, branched-chain amino acids, adipokines, and hepatokines. Finally, in section VIII, we propose an integrated model of insulin resistance that links these mediators to final common pathways of metabolite-driven gluconeogenesis and ectopic lipid accumulation.
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Affiliation(s)
- Max C Petersen
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
| | - Gerald I Shulman
- Departments of Internal Medicine and Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University School of Medicine , New Haven, Connecticut
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Lin JS, Dong HL, Chen GD, Chen ZY, Dong XW, Zheng JS, Chen YM. Erythrocyte Saturated Fatty Acids and Incident Type 2 Diabetes in Chinese Men and Women: A Prospective Cohort Study. Nutrients 2018; 10:E1393. [PMID: 30275386 PMCID: PMC6212875 DOI: 10.3390/nu10101393] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/11/2018] [Accepted: 09/22/2018] [Indexed: 12/23/2022] Open
Abstract
The association between circulating saturated fatty acids (SFAs) and incident type 2 diabetes (T2D) is reported in Western populations with inconsistent results, while evidence from Asian populations is scarce. We aimed to examine the associations between erythrocyte SFAs and incident T2D in a Chinese population. Between 2008 and 2013, a total of 2683 participants, aged 40⁻75 years, free of diabetes were included in the present analyses. Incident T2D cases were ascertained during follow-up visits. Gas chromatography was used to measure erythrocyte fatty acids at baseline. The Cox proportional hazards model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs). During 13,508 person years of follow-up, 216 T2D cases were identified. Compared with the first quartile, multivariable-adjusted HRs (95% CIs) of the fourth quartile were 1.20 (0.82⁻1.76; p = 0.242) for myristic acid (14-carbon tail, zero double bonds; 14:0), 0.69 (0.48⁻0.99; p = 0.080) for palmitic acid (16:0), 1.49 (1.02⁻2.19; p = 0.047) for stearic acid (18:0), 1.46 (1.00⁻2.12; p = 0.035) for arachidic acid (20:0), 1.48 (0.99⁻2.22; p = 0.061) for behenic acid (22:0), and 1.08 (0.74⁻1.56; p = 0.913) for lignoceric acid (24:0). Our findings indicate that individual erythrocyte SFAs are associated with T2D in different directions, with 18:0 and 20:0 SFAs positively associated with the risk, whereas no convincing inverse association for 16:0 SFAs.
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Affiliation(s)
- Jie-Sheng Lin
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Hong-Li Dong
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Geng-Dong Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Zhan-Yong Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Xiao-Wei Dong
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
| | - Ju-Sheng Zheng
- Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Westlake University, Hangzhou 310024, China.
| | - Yu-Ming Chen
- Guangdong Provincial Key Laboratory of Food, Nutrition and Health; Department of Medical Statistics & Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou 510080, China.
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Tse EK, Belsham DD. Palmitate induces neuroinflammation, ER stress, and Pomc mRNA expression in hypothalamic mHypoA-POMC/GFP neurons through novel mechanisms that are prevented by oleate. Mol Cell Endocrinol 2018; 472:40-49. [PMID: 29180108 DOI: 10.1016/j.mce.2017.11.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/10/2017] [Accepted: 11/23/2017] [Indexed: 01/17/2023]
Abstract
Dietary fats can modulate brain function. How free fatty acids (FFAs) alter hypothalamic pro-opiomelanocortin (POMC) neurons remain undefined. The saturated FFA, palmitate, increased neuroinflammatory and ER stress markers, as well as Pomc mRNA levels, but did not affect insulin signaling, in mHypoA-POMC/GFP-2 neurons. This effect was mediated through the MAP kinases JNK and ERK. Further, the increase in Pomc was dependent on palmitoyl-coA synthesis, but not de novo ceramide synthesis, as inhibition of SPT enhanced palmitate-induced Pomc expression, while methylpalmitate had no effect. While palmitate concomitantly induces neuroinflammation and ER stress, these effects were independent of changes in Pomc expression. Palmitate thus has direct acute effects on Pomc, which appears to be important for negative feedback, but not directly related to neuroinflammation. The monounsaturated FFA oleate completely blocked the palmitate-mediated increase in neuroinflammation, ER stress, and Pomc mRNAs. This study provides insight into the complex central metabolic regulation by FFAs.
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Affiliation(s)
- Erika K Tse
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Denise D Belsham
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Departments of Medicine and Obstetrics and Gynaecology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Metcalfe LK, Smith GC, Turner N. Defining lipid mediators of insulin resistance - controversies and challenges. J Mol Endocrinol 2018; 62:JME-18-0023. [PMID: 30068522 DOI: 10.1530/jme-18-0023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 07/04/2018] [Accepted: 07/31/2018] [Indexed: 12/31/2022]
Abstract
Essential elements of all cells, lipids play important roles in energy production, signalling and as structural components. Despite these critical functions, excessive availability and intracellular accumulation of lipid is now recognised as a major factor contributing to many human diseases, including obesity and diabetes. In the context of these metabolic disorders, ectopic deposition of lipid has been proposed to have deleterious effects of insulin action. While this relationship has been recognised for some time now, there is currently no unifying mechanism to explain how lipids precipitate the development of insulin resistance. This review summarises the evidence linking specific lipid molecules to the induction of insulin resistance, describing some of the current controversies and challenges for future studies in this field.
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Affiliation(s)
- Louise K Metcalfe
- L Metcalfe, Department of Pharmacology, School of Medical Sciences, UNSW Australia, Kensington, Australia
| | - Greg C Smith
- G Smith, Department of Pharmacology, School of Medical Sciences, UNSW Australia, Kensington, Australia
| | - Nigel Turner
- N Turner, Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia
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Puerarin attenuates palmitate-induced mitochondrial dysfunction, impaired mitophagy and inflammation in L6 myotubes. Life Sci 2018; 206:84-92. [DOI: 10.1016/j.lfs.2018.05.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 01/16/2023]
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Régnier M, Polizzi A, Guillou H, Loiseau N. Sphingolipid metabolism in non-alcoholic fatty liver diseases. Biochimie 2018; 159:9-22. [PMID: 30071259 DOI: 10.1016/j.biochi.2018.07.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022]
Abstract
Non-alcoholic fatty liver disease (NAFLD) involves a panel of pathologies starting with hepatic steatosis and continuing to irreversible and serious conditions like steatohepatitis (NASH) and hepatocarcinoma. NAFLD is multifactorial in origin and corresponds to abnormal fat deposition in liver. Even if triglycerides are mostly associated with these pathologies, other lipid moieties seem to be involved in the development and severity of NAFLD. That is the case with sphingolipids and more particularly ceramides. In this review, we explore the relationship between NAFLD and sphingolipid metabolism. After providing an analysis of complex sphingolipid metabolism, we focus on the potential involvement of sphingolipids in the different pathologies associated with NAFLD. An unbalanced ratio between ceramides and terminal metabolic products in the liver and plasma promotes weight gain, inflammation, and insulin resistance. In the etiology of NAFLD, some sphingolipid species such as ceramides may be potential biomarkers for NAFLD. We review the clinical relevance of sphingolipids in liver diseases.
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Affiliation(s)
- Marion Régnier
- INRA UMR1331, ToxAlim, Chemin de Tournefeuille, 31027 Toulouse, France
| | - Arnaud Polizzi
- INRA UMR1331, ToxAlim, Chemin de Tournefeuille, 31027 Toulouse, France
| | - Hervé Guillou
- INRA UMR1331, ToxAlim, Chemin de Tournefeuille, 31027 Toulouse, France
| | - Nicolas Loiseau
- INRA UMR1331, ToxAlim, Chemin de Tournefeuille, 31027 Toulouse, France.
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124
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Li X, Jin SJ, Su J, Li XX, Xu M. Acid Sphingomyelinase Down-regulation Alleviates Vascular Endothelial Insulin Resistance in Diabetic Rats. Basic Clin Pharmacol Toxicol 2018; 123:645-659. [PMID: 29923306 DOI: 10.1111/bcpt.13073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/11/2018] [Indexed: 12/17/2022]
Abstract
Insulin resistance in endothelial cells contributes to the development of cardiovascular disease in patients with type 2 diabetes. Acid sphingomyelinase (ASM) is a soluble glycoprotein which plays a vital role in the development and progression of various diseases such as cardiovascular and metabolic diseases. However, it remains unknown if ASM regulates insulin resistance in vascular endothelial cells in type 2 diabetes. ASM down-regulation with gene silencing and selective inhibitor amitriptyline was used in the rat aortic endothelial cells (RAECs) treated with palmitic acid (PA), a common saturated free fatty acid, which is thought to be the major cause of insulin resistance. It was shown that ASM down-regulation increased glucose uptake and glucose transporter-4 (Glut4) expression and reversed the phosphorylation of pIRS-1-ser307 and AKT-ser473 via ceramide, consequently resulting in the decrease of the production of endothelial nitric oxide synthase (eNOS) and nitric oxide in PA-induced RAECs. We further found that ASM down-regulation blocked the Nox2- and Nox4-dependent superoxide (O2 -· ) generation, which regulated glucose metabolism in RAECs during PA stimulation. In vivo, amitriptyline relieved the vasodilatory response to acetylcholine and restored the level of ceramide, Nox2 and Nox4 in the aorta endothelium of high-fat diet-fed rats following an injection of streptozotocin. Taken together, these results suggest that ASM down-regulation can improve endothelial insulin resistance which is attributed to inhibiting redox signalling in RAECs. Thus, these data support the idea that ASM is a promising clinical biomarker and potential therapeutic target for diabetic vascular complication.
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Affiliation(s)
- Xin Li
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Shi-Jie Jin
- School of Pharmacy, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jie Su
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xiao-Xue Li
- Department of Pathology, Medical School of Southeast University, Nanjing, China
| | - Ming Xu
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
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125
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Qin N, Bayat AR, Trevisi E, Minuti A, Kairenius P, Viitala S, Mutikainen M, Leskinen H, Elo K, Kokkonen T, Vilkki J. Dietary supplement of conjugated linoleic acids or polyunsaturated fatty acids suppressed the mobilization of body fat reserves in dairy cows at early lactation through different pathways. J Dairy Sci 2018; 101:7954-7970. [PMID: 29960784 DOI: 10.3168/jds.2017-14298] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/08/2018] [Indexed: 01/25/2023]
Abstract
To investigate the metabolic changes in the adipose tissue (AT) of dairy cows under milk fat depression (MFD), 30 cows were randomly allocated to a control diet, a conjugated linoleic acid (CLA)-supplemented diet, or a high-starch diet supplemented with a mixture of sunflower and fish oil (2:1; as HSO diet) from 1 to 112 d in milk. Performance of animals, milk yield, milk composition, energy balance, and blood metabolites were measured during lactation. Quantitative PCR analyses were conducted on the AT samples collected at wk 3 and 15 of lactation. The CLA and HSO diets considerably depressed milk fat yield and milk fat content at both wk 3 and 15 in the absence of significant changes in milk protein and lactose contents. In addition, the HSO diet lowered milk yield at wk 15 and decreased dry matter intake of cows from wk 3 to 15. Compared with the control, both CLA and HSO groups showed reduced body weight loss, improved energy balance, and decreased plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate at early lactation. The gene expression analyses reflected suppressed lipolysis in AT of the CLA and HSO groups compared with the control at wk 3, as suggested by the downregulation of hormone-sensitive lipase and fatty acid binding protein 4 and the upregulation of perilipin 2. In addition, the HSO diet promoted lipogenesis in AT at wk 15 through the upregulation of 1-acylglycerol-3-phosphate O-acyltransferase 2, mitochondrial glycerol-3-phosphate acyltransferase, perilipin 2, and peroxisome proliferator-activated receptor γ. The CLA diet likely regulated insulin sensitivity in AT as it upregulated the transcription of various genes involved in insulin signaling, inflammatory responses, and ceramide metabolism, including protein kinase B2, nuclear factor κ B1, toll-like receptor 4, caveolin 1, serine palmitoyltransferase long chain base subunit 1, and N-acylsphingosine amidohydrolase 1. In contrast, the HSO diet resulted in little or no change in the pathways relevant to insulin sensitivity. In conclusion, the CLA and HSO diets induced a shift in energy partitioning toward AT instead of mammary gland during lactation through the regulation of different pathways.
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Affiliation(s)
- Nanbing Qin
- Department of Agricultural Sciences, PO Box 28, FI-00014 University of Helsinki, Finland
| | - Ali-Reza Bayat
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland
| | - Erminio Trevisi
- Department of Animal Sciences, Food and Nutrition, Faculty of Agriculture, Food and Environmental Science, Università Cattolica del Sacro Cuore, 20123 Milan, Italy
| | - Andrea Minuti
- Department of Animal Sciences, Food and Nutrition, Faculty of Agriculture, Food and Environmental Science, Università Cattolica del Sacro Cuore, 20123 Milan, Italy
| | - Piia Kairenius
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland
| | - Sirja Viitala
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland
| | - Mervi Mutikainen
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland
| | - Heidi Leskinen
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland
| | - Kari Elo
- Department of Agricultural Sciences, PO Box 28, FI-00014 University of Helsinki, Finland
| | - Tuomo Kokkonen
- Department of Agricultural Sciences, PO Box 28, FI-00014 University of Helsinki, Finland
| | - Johanna Vilkki
- Production Systems, Natural Resources Institute Finland (Luke), 31600 Jokioinen, Finland.
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126
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Bosquet A, Girona J, Guaita-Esteruelas S, Heras M, Saavedra-García P, Martínez-Micaelo N, Masana L, Rodríguez-Calvo R. FABP4 inhibitor BMS309403 decreases saturated-fatty-acid-induced endoplasmic reticulum stress-associated inflammation in skeletal muscle by reducing p38 MAPK activation. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:604-613. [DOI: 10.1016/j.bbalip.2018.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/02/2018] [Accepted: 03/13/2018] [Indexed: 12/12/2022]
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The Effect of Lean-Seafood and Non-Seafood Diets on Fasting and Postprandial Serum Metabolites and Lipid Species: Results from a Randomized Crossover Intervention Study in Healthy Adults. Nutrients 2018; 10:nu10050598. [PMID: 29751643 PMCID: PMC5986478 DOI: 10.3390/nu10050598] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/02/2018] [Accepted: 05/09/2018] [Indexed: 12/24/2022] Open
Abstract
The metabolic effects associated with intake of different dietary protein sources are not well characterized. We aimed to elucidate how two diets that varied in main protein sources affected the fasting and postprandial serum metabolites and lipid species. In a randomized controlled trial with crossover design, healthy adults (n = 20) underwent a 4-week intervention with two balanced diets that varied mainly in protein source (lean-seafood versus non-seafood proteins). Nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry analyses were applied to examine the effects of the two diets on serum metabolites. In the fasting state, the lean-seafood diet period, as opposed to the non-seafood diet period, significantly decreased the serum levels of isoleucine and valine, and during the postprandial state, a decreased level of lactate and increased levels of citrate and trimethylamine N-oxide were observed. The non-seafood diet significantly increased the fasting level of 26 lipid species including ceramides 18:1/14:0 and 18:1/23:0 and lysophosphatidylcholines 20:4 and 22:5, as compared to the lean-seafood diet. Thus, the lean-seafood diet decreased circulating isoleucine and valine levels, whereas the non-seafood diet elevated the levels of certain ceramides, metabolites that are associated with insulin-resistance.
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128
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An aPPARent Functional Consequence in Skeletal Muscle Physiology via Peroxisome Proliferator-Activated Receptors. Int J Mol Sci 2018; 19:ijms19051425. [PMID: 29747466 PMCID: PMC5983589 DOI: 10.3390/ijms19051425] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/05/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle comprises 30–40% of the total body mass and plays a central role in energy homeostasis in the body. The deregulation of energy homeostasis is a common underlying characteristic of metabolic syndrome. Over the past decades, peroxisome proliferator-activated receptors (PPARs) have been shown to play critical regulatory roles in skeletal muscle. The three family members of PPAR have overlapping roles that contribute to the myriad of processes in skeletal muscle. This review aims to provide an overview of the functions of different PPAR members in energy homeostasis as well as during skeletal muscle metabolic disorders, with a particular focus on human and relevant mouse model studies.
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129
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Ghosh N, Katare R. Molecular mechanism of diabetic cardiomyopathy and modulation of microRNA function by synthetic oligonucleotides. Cardiovasc Diabetol 2018; 17:43. [PMID: 29566757 PMCID: PMC5863891 DOI: 10.1186/s12933-018-0684-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/10/2018] [Indexed: 02/06/2023] Open
Abstract
Diabetic cardiomyopathy (DCM) is a chronic complication in individuals with diabetes and is characterized by ventricular dilation and hypertrophy, diastolic dysfunction, decreased or preserved systolic function and reduced ejection fraction eventually resulting in heart failure. Despite being well characterized, the fundamental mechanisms leading to DCM are still elusive. Recent studies identified the involvement of small non-coding small RNA molecules such as microRNAs (miRs) playing a key role in the etiology of DCM. Therefore, miRs associated with DCM represents a new class of targets for the development of mechanistic therapeutics, which may yield marked benefits compared to other therapeutic approaches. Indeed, few miRs currently under active clinical investigation, with many expressing cautious optimism that miRs based therapies will succeed in the coming years. The major caution in using miRs based therapy is the need to improve the stability and specificity following systemic injection, which can be achieved through chemical and structural modification. In this review, we first discuss the established role of miRs in DCM and the advances in miRs based therapeutic strategies for the prevention/treatment of DCM. We next discuss the currently employed chemical modification of miR oligonucleotides and their utility in therapies specifically focusing on the DCM. Finally, we summarize the commonly used delivery system and approaches for assessment of miRNA modulation and potential off-target effects.
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Affiliation(s)
- Nilanjan Ghosh
- Department of Physiology-HeartOtago, University of Otago, 270, Great King Street, Dunedin, 9010 New Zealand
| | - Rajesh Katare
- Department of Physiology-HeartOtago, University of Otago, 270, Great King Street, Dunedin, 9010 New Zealand
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130
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Small L, Brandon AE, Turner N, Cooney GJ. Modeling insulin resistance in rodents by alterations in diet: what have high-fat and high-calorie diets revealed? Am J Physiol Endocrinol Metab 2018; 314:E251-E265. [PMID: 29118016 DOI: 10.1152/ajpendo.00337.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
For over half a century, researchers have been feeding different diets to rodents to examine the effects of macronutrients on whole body and tissue insulin action. During this period, the number of different diets and the source of macronutrients employed have grown dramatically. Because of the large heterogeneity in both the source and percentage of different macronutrients used for studies, it is not surprising that different high-calorie diets do not produce the same changes in insulin action. Despite this, diverse high-calorie diets continue to be employed in an attempt to generate a "generic" insulin resistance. The high-fat diet in particular varies greatly between studies with regard to the source, complexity, and ratio of dietary fat, carbohydrate, and protein. This review examines the range of rodent dietary models and methods for assessing insulin action. In almost all studies reviewed, rodents fed diets that had more than 45% of dietary energy as fat or simple carbohydrates had reduced whole body insulin action compared with chow. However, different high-calorie diets produced significantly different effects in liver, muscle, and whole body insulin action when insulin action was measured by the hyperinsulinemic-euglycemic clamp method. Rodent dietary models remain an important tool for exploring potential mechanisms of insulin resistance, but more attention needs to be given to the total macronutrient content and composition when interpreting dietary effects on insulin action.
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Affiliation(s)
- Lewin Small
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
| | - Amanda E Brandon
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
- Sydney Medical School, Charles Perkins Centre, The University of Sydney , New South Wales , Australia
| | - Nigel Turner
- Department of Pharmacology, School of Medical Science, University of New South Wales , Sydney, New South Wales , Australia
| | - Gregory J Cooney
- Diabetes and Metabolism Division, Garvan Institute , Sydney, New South Wales , Australia
- Sydney Medical School, Charles Perkins Centre, The University of Sydney , New South Wales , Australia
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131
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Fazakerley DJ, Chaudhuri R, Yang P, Maghzal GJ, Thomas KC, Krycer JR, Humphrey SJ, Parker BL, Fisher-Wellman KH, Meoli CC, Hoffman NJ, Diskin C, Burchfield JG, Cowley MJ, Kaplan W, Modrusan Z, Kolumam G, Yang JY, Chen DL, Samocha-Bonet D, Greenfield JR, Hoehn KL, Stocker R, James DE. Mitochondrial CoQ deficiency is a common driver of mitochondrial oxidants and insulin resistance. eLife 2018; 7:32111. [PMID: 29402381 PMCID: PMC5800848 DOI: 10.7554/elife.32111] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/02/2018] [Indexed: 12/11/2022] Open
Abstract
Insulin resistance in muscle, adipocytes and liver is a gateway to a number of metabolic diseases. Here, we show a selective deficiency in mitochondrial coenzyme Q (CoQ) in insulin-resistant adipose and muscle tissue. This defect was observed in a range of in vitro insulin resistance models and adipose tissue from insulin-resistant humans and was concomitant with lower expression of mevalonate/CoQ biosynthesis pathway proteins in most models. Pharmacologic or genetic manipulations that decreased mitochondrial CoQ triggered mitochondrial oxidants and insulin resistance while CoQ supplementation in either insulin-resistant cell models or mice restored normal insulin sensitivity. Specifically, lowering of mitochondrial CoQ caused insulin resistance in adipocytes as a result of increased superoxide/hydrogen peroxide production via complex II. These data suggest that mitochondrial CoQ is a proximal driver of mitochondrial oxidants and insulin resistance, and that mechanisms that restore mitochondrial CoQ may be effective therapeutic targets for treating insulin resistance. After we eat, our blood sugar levels increase. To counteract this, the pancreas releases a hormone called insulin. Part of insulin’s effect is to promote the uptake of sugar from the blood into muscle and fat tissue for storage. Under certain conditions, such as obesity, this process can become defective, leading to a condition known as insulin resistance. This condition makes a number of human diseases more likely to develop, including type 2 diabetes. Working out how insulin resistance develops could therefore unveil new treatment strategies for these diseases. Mitochondria – structures that produce most of a cell’s energy supply – appear to play a role in the development of insulin resistance. Mitochondria convert nutrients such as fats and sugars into molecules called ATP that fuel the many processes required for life. However, ATP production can also generate potentially harmful intermediates often referred to as ‘reactive oxygen species’ or ‘oxidants’. Previous studies have suggested that an increase in the amount of oxidants produced in mitochondria can cause insulin resistance. Fazakerley et al. therefore set out to identify the reason for increased oxidants in mitochondria, and did so by analysing the levels of proteins and oxidants found in cells grown in the laboratory, and mouse and human tissue samples. This led them to find that concentrations of a molecule called coenzyme Q (CoQ), an essential component of mitochondria that helps to produce ATP, were lower in mitochondria from insulin-resistant fat and muscle tissue. Further experiments suggested a link between the lower levels of CoQ and the higher levels of oxidants in the mitochondria. Replenishing the mitochondria of the lab-grown cells and insulin-resistant mice with CoQ restored ‘normal’ oxidant levels and prevented the development of insulin resistance. Strategies that aim to increase mitochondria CoQ levels may therefore prevent or reverse insulin resistance. Although CoQ supplements are readily available, swallowing CoQ does not efficiently deliver CoQ to mitochondria in humans, so alternative treatment methods must be found. It is also of interest that statins, common drugs taken by millions of people around the world to lower cholesterol, also lower CoQ and have been reported to increase the risk of developing type 2 diabetes. Further research is therefore needed to investigate whether CoQ might provide the link between statins and type 2 diabetes.
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Affiliation(s)
- Daniel J Fazakerley
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Rima Chaudhuri
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Pengyi Yang
- School of Mathematics and Statistics, University of Sydney, Camperdown, Australia
| | - Ghassan J Maghzal
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Kristen C Thomas
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - James R Krycer
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Sean J Humphrey
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Benjamin L Parker
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Kelsey H Fisher-Wellman
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, United States
| | - Christopher C Meoli
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Nolan J Hoffman
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Ciana Diskin
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - James G Burchfield
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia
| | - Mark J Cowley
- The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Darlinghurst, Australia
| | - Warren Kaplan
- Peter Wills Bioinformatics Centre, Garvan Institute of Medical Research, Darlinghurst, Australia
| | | | | | - Jean Yh Yang
- School of Mathematics and Statistics, University of Sydney, Camperdown, Australia
| | - Daniel L Chen
- Garvan Institute of Medical Research, Darlinghurst, Australia
| | | | | | - Kyle L Hoehn
- School of Biotechnology and Biomedical Sciences, University of New South Wales, Sydney, Australia
| | - Roland Stocker
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Australia.,St Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | - David E James
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Camperdown, Australia.,Charles Perkins Centre, Sydney Medical School, University of Sydney, Camperdown NSW, Australia
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132
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Rico JE, Myers WA, Laub DJ, Davis AN, Zeng Q, McFadden JW. Hot topic: Ceramide inhibits insulin sensitivity in primary bovine adipocytes. J Dairy Sci 2018; 101:3428-3432. [PMID: 29395144 DOI: 10.3168/jds.2017-13983] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 12/21/2017] [Indexed: 12/31/2022]
Abstract
In nonruminants, the sphingolipid ceramide inhibits insulin sensitivity by inactivating protein kinase B (AKT) within the insulin-signaling pathway. We have established that ceramide accrual develops with impaired systemic insulin action in ruminants during the transition from gestation to lactation, dietary palmitic acid supplementation, or controlled nutrient restriction. We hypothesized that ceramide promotes AKT inactivation and antagonizes insulin sensitivity in primary bovine adipocytes. Stromal-vascular cells were grown from bovine adipose tissue explants and cultured in differentiation media. To modify ceramide supply, we treated differentiated adipocytes with (1) myriocin, an inhibitor of de novo ceramide synthesis, or (2) cell-permeable C2:0-ceramide. Insulin-stimulated AKT activation (i.e., phosphorylation) and 2-deoxy-D-[3H]-glucose (2DOG) uptake were measured. Treatment of adipocytes with myriocin consistently decreased concentrations of ceramide, monohexosylceramide, and lactosylceramide. The insulin-stimulated ratio of phosphorylated AKT to total AKT was increased with myriocin but decreased with C2:0-ceramide. Moreover, adipocyte insulin-stimulated 2DOG uptake was decreased with C2:0-ceramide and increased with myriocin. We conclude that ceramide inhibits insulin-stimulated glucose uptake by downregulating AKT activation in primary bovine adipocytes.
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Affiliation(s)
- J E Rico
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505; Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - W A Myers
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505; Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - D J Laub
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505
| | - A N Davis
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505; Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - Q Zeng
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505
| | - J W McFadden
- Division of Animal and Nutritional Sciences, West Virginia University, Morgantown 26505; Department of Animal Science, Cornell University, Ithaca, NY 14853.
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Law BA, Hancock WD, Cowart LA. Getting to the heart of the sphingolipid riddle. CURRENT OPINION IN PHYSIOLOGY 2018; 1:111-122. [PMID: 33195889 PMCID: PMC7665081 DOI: 10.1016/j.cophys.2017.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Obesity, Type 2 Diabetes, and Metabolic Syndrome induce dyslipidemia resulting in inundation of peripheral organs with fatty acids. These not only serve as substrates for energy production, but also contribute to aberrant production of bioactive lipids. Moreover, lipid metabolism is affected in many cardiac disorders including heart failure, ischemia reperfusion injury, and others. While lipids serve crucial homeostatic roles, perturbing biosynthesis of lipid mediators leads to aberrant cell signaling, which contributes to maladaptive cardiovascular programs. Bioactive sphingolipids, in particular, have been implicated in pathophysiology in the heart and vasculature by a variety of studies in cells, animal models, and humans. Because of the burgeoning interest in sphingolipid-driven biology in the cardiovascular system, it is necessary to discuss the experimental considerations for studying sphingolipid metabolism and signaling, emphasizing the caveats to some widely available experimental tools and approaches. Additionally, there is a growing appreciation for the diversity of ceramide structures generated via specific enzymes and bearing disparate cellular functions. While targeting these individual species and enzymes constitutes a major advance, studies show that sphingolipid synthesis readily adapts to compensate for experimental targeting of any individual pathway, thereby convoluting data interpretation. Furthermore, though some molecular mechanisms of sphingolipid action are known, signaling pathways impacted by sphingolipids remain incompletely understood. In this review, we discuss these issues and highlight recent studies as well as future directions that may extend our understanding of the metabolism and signaling actions of these enigmatic lipids in the cardiovascular context.
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Affiliation(s)
- Britany A Law
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC
- Present Address: Department of Medicine-Cardiology, Duke University, Durham NC
| | - William D. Hancock
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC
| | - L Ashley Cowart
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC
- Ralph H. Johnson Veteran’s Affairs Medical Center, Charleston, SC
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Inhibition of insulin resistance by PGE1 via autophagy-dependent FGF21 pathway in diabetic nephropathy. Sci Rep 2018; 8:9. [PMID: 29311680 PMCID: PMC5758726 DOI: 10.1038/s41598-017-18427-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 12/11/2017] [Indexed: 12/22/2022] Open
Abstract
Insulin resistance is a critical process in the initiation and progression of diabetic nephropathy (DN). Alprostadil (Prostaglandin E1, PGE1) had protective effects on renal function. However, it is unknown whether PGE1 inhibited insulin resistance in renal tubule epithelial cells via autophagy, which plays a protective role in DN against insulin resistance. Insulin resistance was induced by palmitic acid (PA) in human HK-2 cells, shown as the decrease of insulin-stimulated AKT phosphorylation, glucose transporter-4 (GLUT4), glucose uptake and enhanced phosphorylation of insulin receptor substrate 1(IRS-1) at site serine 307 (pIRS-1ser307) and downregulated expression of IRS-1. Along with less abundance of p62, autophagy markers LC3B and Beclin-1 significantly increased in HK-2 cells exposed to PA. Such abnormal changes were significantly reversed by PGE1, which mimicked the role of autophagy gene 7 small interfering RNA (ATG7 siRNA). Furthermore, PGE1 promoted the protein expression of autophagy-related fibroblast growth factor-21 (FGF21), which alleviated insulin resistance. Results from western blotting and immunohistochemistry indicated that PGE1 remarkably restored autophagy, insulin resistance and the FGF21 expression in rat kidney of type 2 diabetes mellitus (T2DM). Collectively, we demonstrated the potential protection of PGE1 on insulin resistance in renal tubules via autophagy-dependent FGF21 pathway in preventing the progression of DN.
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135
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Oh YS, Bae GD, Baek DJ, Park EY, Jun HS. Fatty Acid-Induced Lipotoxicity in Pancreatic Beta-Cells During Development of Type 2 Diabetes. Front Endocrinol (Lausanne) 2018; 9:384. [PMID: 30061862 PMCID: PMC6054968 DOI: 10.3389/fendo.2018.00384] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes is caused by chronic insulin resistance and progressive decline in beta-cell function. Optimal beta-cell function and mass is essential for glucose homeostasis and beta-cell impairment leads to the development of diabetes. Elevated levels of circulating fatty acids (FAs) and disturbances in lipid metabolism regulation are associated with obesity, and they are major factors influencing the increase in the incidence of type 2 diabetes. Chronic free FA (FFA) treatment induces insulin resistance and beta-cell dysfunction; therefore, reduction of elevated plasma FFA levels might be an important therapeutic target in obesity and type 2 diabetes. Lipid signals via receptors, and intracellular mechanisms are involved in FFA-induced apoptosis. In this paper, we discuss lipid actions in beta cells, including effects on metabolic pathways and stress responses, to help further understand the molecular mechanisms of lipotoxicity-induced type 2 diabetes.
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Affiliation(s)
- Yoon S. Oh
- Department of Food and Nutrition, Eulji University, Seongnam, South Korea
- *Correspondence: Yoon S. Oh
| | - Gong D. Bae
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
| | - Dong J. Baek
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Eun-Young Park
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Jeonnam, South Korea
| | - Hee-Sook Jun
- Department of Molecular Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
- Gachon Institute of Pharmaceutical Science, College of Pharmacy, Gachon University, Incheon, South Korea
- Gachon University Gil Medical Center, Gachon Medical and Convergence Institute, Incheon, South Korea
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136
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Chattopadhyay M, Mukherjee S, Chatterjee SK, Chattopadhyay D, Das S, Majumdar SS, Mukhopadhyay S, Mukherjee S, Bhattarcharya S. Impairment of energy sensors, SIRT1 and AMPK, in lipid induced inflamed adipocyte is regulated by Fetuin A. Cell Signal 2018; 42:67-76. [DOI: 10.1016/j.cellsig.2017.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/25/2017] [Accepted: 10/07/2017] [Indexed: 12/20/2022]
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137
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Liu S, Li X, Wu Y, Duan R, Zhang J, Du F, Zhang Q, Li Y, Li N. Effects of vaspin on pancreatic β cell secretion via PI3K/Akt and NF-κB signaling pathways. PLoS One 2017; 12:e0189722. [PMID: 29240812 PMCID: PMC5730172 DOI: 10.1371/journal.pone.0189722] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 11/30/2017] [Indexed: 01/11/2023] Open
Abstract
Vaspin (visceral adipose tissue-derived serine protease inhibitor) is a recently discovered adipokine that has been implicated in diabetes mellitus and other metabolic disorders. However, the effects of vaspin on pancreatic β cell function and related mechanisms are not fully understood. Thus, the present study was performed to investigate the effects of vaspin on pancreatic β cell function and the potential underlying mechanisms. Both in vitro (rat insulinoma cells, INS-1) and in vivo (high fat diet fed rats) experiments were conducted. The results showed that vaspin significantly increased INS-1 cell secretory function. Potential mechanisms were explored using inhibitors, western blot and real-time PCR techniques. We found that vaspin increased the levels of IRS-2 mRNA and IRS-2 total protein, while decreased the serine phosphorylation level of IRS-2 protein. Moreover, vaspin increased the Akt phosphorylation protein level which was reversed by PI3K inhibitor ly294002. In addition, vaspin increased the phosphorylation levels of mTOR and p70S6K, which was inhibited by rapamycin. Meanwhile, we found that the NF-κB mRNA and protein levels were reduced after vaspin treatment, similar to the effect of NF-κB inhibitor TPCK. Furthermore, vaspin increased the glucose stimulated insulin secretion (GSIS) level, lowered blood glucose level and improved the glucose tolerance and insulin sensitivity of high fat diet fed rats. Hyperglycemic clamp test manifested that vaspin improved islet β cell function. Together, these findings provide a new understanding of the function of vaspin on pancreatic β cell and suggest that it may serve as a potential agent for the prevention and treatment of type 2 diabetes.
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Affiliation(s)
- Shiwei Liu
- Department of Endocrinology, Shanxi DAYI Hospital, Shanxi Medical University, Taiyuan, China
- Central Laboratory, Taiyuan Central Hospital, Shanxi Medical University, Taiyuan, China
- * E-mail:
| | - Xin Li
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Yaru Wu
- Central Laboratory, Taiyuan Central Hospital, Shanxi Medical University, Taiyuan, China
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Ruixue Duan
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Jiaxin Zhang
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Fang Du
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Qi Zhang
- Graduate School of Shanxi Medical University, Taiyuan, China
| | - Yuanbin Li
- Department of Endocrinology, Taiyuan Central Hospital, Shanxi Medical University, Taiyuan, China
| | - Naishi Li
- Department of Endocrinology, Key Laboratory of Endocrinology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing, China
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138
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Olver TD, Grunewald ZI, Jurrissen TJ, MacPherson REK, LeBlanc PJ, Schnurbusch TR, Czajkowski AM, Laughlin MH, Rector RS, Bender SB, Walters EM, Emter CA, Padilla J. Microvascular insulin resistance in skeletal muscle and brain occurs early in the development of juvenile obesity in pigs. Am J Physiol Regul Integr Comp Physiol 2017; 314:R252-R264. [PMID: 29141949 DOI: 10.1152/ajpregu.00213.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Impaired microvascular insulin signaling may develop before overt indices of microvascular endothelial dysfunction and represent an early pathological feature of adolescent obesity. Using a translational porcine model of juvenile obesity, we tested the hypotheses that in the early stages of obesity development, impaired insulin signaling manifests in skeletal muscle (triceps), brain (prefrontal cortex), and corresponding vasculatures, and that depressed insulin-induced vasodilation is reversible with acute inhibition of protein kinase Cβ (PKCβ). Juvenile Ossabaw miniature swine (3.5 mo of age) were divided into two groups: lean control ( n = 6) and obese ( n = 6). Obesity was induced by feeding the animals a high-fat/high-fructose corn syrup/high-cholesterol diet for 10 wk. Juvenile obesity was characterized by excess body mass, hyperglycemia, physical inactivity (accelerometer), and marked lipid accumulation in the skeletal muscle, with no evidence of overt atherosclerotic lesions in athero-prone regions, such as the abdominal aorta. Endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) vasomotor responses in the brachial and carotid arteries (wire myography), as well as in the skeletal muscle resistance and 2A pial arterioles (pressure myography) were unaltered, but insulin-induced microvascular vasodilation was impaired in the obese group. Blunted insulin-stimulated vasodilation, which was reversed with acute PKCβ inhibition (LY333-531), occurred alongside decreased tissue perfusion, as well as reduced insulin-stimulated Akt signaling in the prefrontal cortex, but not the triceps. In the early stages of juvenile obesity development, the microvasculature and prefrontal cortex exhibit impaired insulin signaling. Such adaptations may underscore vascular and neurological derangements associated with juvenile obesity.
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Affiliation(s)
- T Dylan Olver
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri
| | - Zachary I Grunewald
- Department of Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri
| | - Thomas J Jurrissen
- Department of Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri
| | | | - Paul J LeBlanc
- Department of Health Sciences, Brock University , St. Catharines, Ontario , Canada
| | - Teagan R Schnurbusch
- National Swine Resource and Research Center University of Missouri , Columbia, Missouri
| | - Alana M Czajkowski
- National Swine Resource and Research Center University of Missouri , Columbia, Missouri
| | - M Harold Laughlin
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri
| | - R Scott Rector
- Department of Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri.,Research Service, Harry S. Truman Memorial Veterans Affairs Hospital , Columbia, Missouri.,Department of Medicine, Division of Gastroenterology and Hepatology, University of Missouri , Columbia, Missouri
| | - Shawn B Bender
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri.,Research Service, Harry S. Truman Memorial Veterans Affairs Hospital , Columbia, Missouri
| | - Eric M Walters
- National Swine Resource and Research Center University of Missouri , Columbia, Missouri
| | - Craig A Emter
- Department of Biomedical Sciences, University of Missouri , Columbia, Missouri
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri , Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri , Columbia, Missouri.,Department of Child Health, University of Missouri , Columbia, Missouri
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139
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Interleukin-6 deficiency facilitates myocardial dysfunction during high fat diet-induced obesity by promoting lipotoxicity and inflammation. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3128-3141. [DOI: 10.1016/j.bbadis.2017.08.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 12/28/2022]
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140
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Abou Daher A, El Jalkh T, Eid AA, Fornoni A, Marples B, Zeidan YH. Translational Aspects of Sphingolipid Metabolism in Renal Disorders. Int J Mol Sci 2017; 18:ijms18122528. [PMID: 29186855 PMCID: PMC5751131 DOI: 10.3390/ijms18122528] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 12/13/2022] Open
Abstract
Sphingolipids, long thought to be passive components of biological membranes with merely a structural role, have proved throughout the past decade to be major players in the pathogenesis of many human diseases. The study and characterization of several genetic disorders like Fabry’s and Tay Sachs, where sphingolipid metabolism is disrupted, leading to a systemic array of clinical symptoms, have indeed helped elucidate and appreciate the importance of sphingolipids and their metabolites as active signaling molecules. In addition to being involved in dynamic cellular processes like apoptosis, senescence and differentiation, sphingolipids are implicated in critical physiological functions such as immune responses and pathophysiological conditions like inflammation and insulin resistance. Interestingly, the kidneys are among the most sensitive organ systems to sphingolipid alterations, rendering these molecules and the enzymes involved in their metabolism, promising therapeutic targets for numerous nephropathic complications that stand behind podocyte injury and renal failure.
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Affiliation(s)
- Alaa Abou Daher
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon.
| | - Tatiana El Jalkh
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon.
| | - Assaad A Eid
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon.
| | - Alessia Fornoni
- Department of Medicine, Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miami, FL 33136, USA.
| | - Brian Marples
- Department of Radiation Oncology, Miller School of Medicine/Sylvester Cancer Center, University of Miami, Miami, FL 33136, USA.
| | - Youssef H Zeidan
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon.
- Department of Radiation Oncology, American University of Beirut Medical Center, Beirut 1107 2020, Lebanon.
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141
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Yang C, Lim W, Bazer FW, Song G. Down-regulation of stearoyl-CoA desaturase-1 increases susceptibility to palmitic-acid-induced lipotoxicity in human trophoblast cells. J Nutr Biochem 2017; 54:35-47. [PMID: 29242171 DOI: 10.1016/j.jnutbio.2017.11.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/12/2017] [Accepted: 11/11/2017] [Indexed: 01/22/2023]
Abstract
In early pregnancy, adequate dietary factors are important for the growth of human trophoblast cells, followed by placental development. Although stearoyl-CoA desaturase 1 (SCD1) is expected to relieve palmitic acid (PA)-induced lipotoxicity by regulating diacylglycerol and ceramide, its function is unclear in human trophoblast cells. The aim was to investigate inhibitory effects of SCD1 activity on PA-induced trophoblast cell death. PA induces cell death and inhibits the invasion of human trophoblast cells (HTR8/SVneo). In addition, we demonstrate that SCD1 has a protective role against PA in human trophoblast cells by regulating AKT-mediated signaling pathway and mitochondrial membrane potential. The knockdown of SCD1 enhances the proapoptotic activity of PA in HTR8/SVneo cells. Lastly, we investigated microRNA expression predicted to target SCD1 and diacylglycerol O-acyltransferase 1 (DGAT1) by PA. Collectively, the results suggest potential roles of SCD1 and DGAT1 in alleviating the toxicity of PA and maintaining lipid homeostasis for normal placentation.
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Affiliation(s)
- Changwon Yang
- Institute of Animal Molecular Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
| | - Whasun Lim
- Department of Biomedical Sciences, Catholic Kwandong University, Gangneung, 25601, Republic of Korea
| | - Fuller W Bazer
- Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, 77843-2471, Texas, USA
| | - Gwonhwa Song
- Institute of Animal Molecular Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea.
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142
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Inhibition of central de novo ceramide synthesis restores insulin signaling in hypothalamus and enhances β-cell function of obese Zucker rats. Mol Metab 2017; 8:23-36. [PMID: 29233519 PMCID: PMC5985020 DOI: 10.1016/j.molmet.2017.10.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/17/2017] [Accepted: 10/27/2017] [Indexed: 12/29/2022] Open
Abstract
Objectives Hypothalamic lipotoxicity has been shown to induce central insulin resistance and dysregulation of glucose homeostasis; nevertheless, elucidation of the regulatory mechanisms remains incomplete. Here, we aimed to determine the role of de novo ceramide synthesis in hypothalamus on the onset of central insulin resistance and the dysregulation of glucose homeostasis induced by obesity. Methods Hypothalamic GT1-7 neuronal cells were treated with palmitate. De novo ceramide synthesis was inhibited either by pharmacological (myriocin) or molecular (si-Serine Palmitoyl Transferase 2, siSPT2) approaches. Obese Zucker rats (OZR) were intracerebroventricularly infused with myriocin to inhibit de novo ceramide synthesis. Insulin resistance was determined by quantification of Akt phosphorylation. Ceramide levels were quantified either by a radioactive kinase assay or by mass spectrometry analysis. Glucose homeostasis were evaluated in myriocin-treated OZR. Basal and glucose-stimulated parasympathetic tonus was recorded in OZR. Insulin secretion from islets and β-cell mass was also determined. Results We show that palmitate impaired insulin signaling and increased ceramide levels in hypothalamic neuronal GT1-7 cells. In addition, the use of deuterated palmitic acid demonstrated that palmitate activated several enzymes of the de novo ceramide synthesis pathway in hypothalamic cells. Importantly, myriocin and siSPT2 treatment restored insulin signaling in palmitate-treated GT1-7 cells. Protein kinase C (PKC) inhibitor or a dominant-negative PKCζ also counteracted palmitate-induced insulin resistance. Interestingly, attenuating the increase in levels of hypothalamic ceramides with intracerebroventricular infusion of myriocin in OZR improved their hypothalamic insulin-sensitivity. Importantly, central myriocin treatment partially restored glucose tolerance in OZR. This latter effect is related to the restoration of glucose-stimulated insulin secretion and an increase in β-cell mass of OZR. Electrophysiological recordings also showed an improvement of glucose-stimulated parasympathetic nerve activity in OZR centrally treated with myriocin. Conclusion Our results highlight a key role of hypothalamic de novo ceramide synthesis in central insulin resistance installation and glucose homeostasis dysregulation associated with obesity. de novo ceramide synthesis induces hypothalamic insulin resistance through PKCζ. Hypothalamic ceramides induce glucose homeostasis dysregulation seen with obesity. Hypothalamic ceramides mediate inhibition of insulin secretion induced by obesity. Hypothalamic ceramides decreases β cell mass in obese rats. Hypothalamic ceramides decreases parasympathetic tonus.
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143
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Montgomery MK, Brown SHJ, Mitchell TW, Coster ACF, Cooney GJ, Turner N. Association of muscle lipidomic profile with high-fat diet-induced insulin resistance across five mouse strains. Sci Rep 2017; 7:13914. [PMID: 29066734 PMCID: PMC5654831 DOI: 10.1038/s41598-017-14214-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/05/2017] [Indexed: 12/20/2022] Open
Abstract
Different mouse strains exhibit variation in their inherent propensities to develop metabolic disease. We recently showed that C57BL6, 129X1, DBA/2 and FVB/N mice are all susceptible to high-fat diet-induced glucose intolerance, while BALB/c mice are relatively protected, despite changes in many factors linked with insulin resistance. One parameter strongly linked with insulin resistance is ectopic lipid accumulation, especially metabolically active ceramides and diacylglycerols (DAG). This study examined diet-induced changes in the skeletal muscle lipidome across these five mouse strains. High-fat feeding increased total muscle triacylglycerol (TAG) content, with elevations in similar triacylglycerol species observed for all strains. There were also generally consistent changes across strains in the abundance of different phospholipid (PL) classes and the fatty acid profile of phospholipid molecular species, with the exception being a strain-specific difference in phospholipid species containing two polyunsaturated fatty acyl chains in BALB/c mice (i.e. a diet-induced decrease in the other four strains, but no change in BALB/c mice). In contrast to TAG and PL, the high-fat diet had a minor influence on DAG and ceramide species across all strains. These results suggest that widespread alterations in muscle lipids are unlikely a major contributors to the favourable metabolic profile of BALB/c mice and rather there is a relatively conserved high-fat diet response in muscle of most mouse strains.
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Affiliation(s)
- Magdalene K Montgomery
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Simon H J Brown
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia
- llawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Todd W Mitchell
- School of Medicine, University of Wollongong, Wollongong, NSW, Australia
- llawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Adelle C F Coster
- School of Mathematics and Statistics, University of New South Wales, Sydney, NSW, Australia
| | - Gregory J Cooney
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Nigel Turner
- Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
- Diabetes & Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
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Abstract
Enlarged fat cells in obese adipose tissue diminish capacity to store fat and are resistant to the anti-lipolytic effect of insulin. Insulin resistance (IR)-associated S-nitrosylation of insulin-signaling proteins increases in obesity. In accordance with the inhibition of insulin-mediated anti-lipolytic action, plasma free fatty acid (FFA) levels increase. Additionally, endoplasmic reticulum stress stimuli induce lipolysis by activating cyclic adenosine monophosphate/Protein kinase A (cAMP/PKA) and extracellular signal-regulated kinase ½ (ERK1/2) signaling in adipocytes. Failure of packaging of excess lipid into lipid droplets causes chronic elevation of circulating fatty acids, which can reach to toxic levels within non-adipose tissues. Deleterious effects of lipid accumulation in non-adipose tissues are known as lipotoxicity. In fact, triglycerides may also serve a storage function for long-chain non-esterified fatty acids and their products such as ceramides and diacylglycerols (DAGs). Thus, excess DAG, ceramide and saturated fatty acids in obesity can induce chronic inflammation and have harmful effect on multiple organs and systems. In this context, chronic adipose tissue inflammation, mitochondrial dysfunction and IR have been discussed within the scope of lipotoxicity.
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145
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Vitamin D supplementation restores the blunted muscle protein synthesis response in deficient old rats through an impact on ectopic fat deposition. J Nutr Biochem 2017; 46:30-38. [DOI: 10.1016/j.jnutbio.2017.02.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 01/23/2017] [Accepted: 02/28/2017] [Indexed: 02/06/2023]
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146
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Kwak HJ, Choi HE, Cheon HG. 5-LO inhibition ameliorates palmitic acid-induced ER stress, oxidative stress and insulin resistance via AMPK activation in murine myotubes. Sci Rep 2017; 7:5025. [PMID: 28694473 PMCID: PMC5504062 DOI: 10.1038/s41598-017-05346-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 06/02/2017] [Indexed: 01/10/2023] Open
Abstract
Leukotriene B4 (LTB4) production via the 5-lipoxygenase (5-LO) pathway contributes to the development of insulin resistance in adipose and hepatic tissues, but the role of LTB4 in skeletal muscle is relatively unknown. Here, the authors investigated the role of LTB4 in C2C12 myotubes in palmitic acid (PA)-induced ER stress, inflammation and insulin resistance. PA (750 μM) evoked lipotoxicity (ER stress, oxidative stress, inflammation and insulin resistance) in association with LTB4 production. 5-LO inhibition reduced all the lipotoxic effects induced by PA. On the other hand, PA did not induce cysteinyl leukotrienes (CysLTs), which themselves had no effect on ER stress and inflammation. The beneficial effects of 5-LO suppression from PA-induced lipotoxicity were related with AMPK activation. In ob/ob mice, once daily oral administration of zileuton (50, 100 mg/kg) for 5 weeks improved insulin resistance, increased AMPK phosphorylation, and reduced LTB4 and ER stress marker expression in skeletal muscle. These results show that 5-LO inhibition by either zileuton or 5-LO siRNA protects C2C12 myotubes from PA-induced lipotoxicity, at least partly via AMPK activation, and suggest that the in vivo insulin-sensitizing effects of zileuton are in part attributable to its direct action on skeletal muscle via LTB4 downregulation followed by AMPK activation.
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Affiliation(s)
- Hyun Jeong Kwak
- Department of Pharmacology, Gachon University College of Medicine, Incheon, 21999, Republic of Korea
| | - Hye-Eun Choi
- Department of Pharmacology, Gachon University College of Medicine, Incheon, 21999, Republic of Korea
| | - Hyae Gyeong Cheon
- Department of Pharmacology, Gachon University College of Medicine, Incheon, 21999, Republic of Korea. .,Gachon Medical Research Institute, Gil Medical Center, Incheon, 21565, Republic of Korea.
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147
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Iqbal J, Walsh MT, Hammad SM, Hussain MM. Sphingolipids and Lipoproteins in Health and Metabolic Disorders. Trends Endocrinol Metab 2017; 28:506-518. [PMID: 28462811 PMCID: PMC5474131 DOI: 10.1016/j.tem.2017.03.005] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 03/09/2017] [Accepted: 03/28/2017] [Indexed: 12/28/2022]
Abstract
Sphingolipids are structurally and functionally diverse molecules with significant physiologic functions and are found associated with cellular membranes and plasma lipoproteins. The cellular and plasma concentrations of sphingolipids are altered in several metabolic disorders and may serve as prognostic and diagnostic markers. Here we discuss various sphingolipid transport mechanisms and highlight how changes in cellular and plasma sphingolipid levels contribute to cardiovascular disease, obesity, diabetes, insulin resistance, and nonalcoholic fatty liver disease (NAFLD). Understanding of the mechanisms involved in intracellular transport, secretion, and extracellular transport may provide novel information that might be amenable to therapeutic targeting for the treatment of various metabolic disorders.
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Affiliation(s)
- Jahangir Iqbal
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA; King Abdullah International Medical Research Center, MNGHA, Al Ahsa 31982, Saudi Arabia
| | - Meghan T Walsh
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA
| | - Samar M Hammad
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - M Mahmood Hussain
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York, NY 11203, USA; VA New York Harbor Healthcare System, Brooklyn, New York, NY 11209; Center for Diabetes and Obesity Research, NYU Winthrop Hospital, Mineola, NY 11501, USA.
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148
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Sun X, Song M, Wang H, Zhou H, Wang F, Li Y, Zhang Y, Zhang W, Zhong M, Ti Y. TRB3 gene silencing activates AMPK in adipose tissue with beneficial metabolic effects in obese and diabetic rats. Biochem Biophys Res Commun 2017; 488:22-28. [DOI: 10.1016/j.bbrc.2017.04.154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 04/30/2017] [Indexed: 02/07/2023]
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149
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Sadeghi A, Seyyed Ebrahimi SS, Golestani A, Meshkani R. Resveratrol Ameliorates Palmitate-Induced Inflammation in Skeletal Muscle Cells by Attenuating Oxidative Stress and JNK/NF-κB Pathway in a SIRT1-Independent Mechanism. J Cell Biochem 2017; 118:2654-2663. [PMID: 28059488 DOI: 10.1002/jcb.25868] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/04/2017] [Indexed: 01/08/2023]
Abstract
Resveratrol has been shown to exert anti-inflammatory and anti-oxidant effects in a variety of cell types, however, its role in prevention of inflammatory responses mediated by palmitate in skeletal muscle cells remains unexplored. In the present study, we investigated the effects of resveratrol on palmitate-induced inflammation and elucidated the underlying mechanisms in skeletal muscle cells. The results showed that palmitate significantly enhanced TNF-α and IL-6 mRNA expression and protein secretion from C2C12 cells at 12, 24, and 36 h treatments. Increased expression of cytokines was accompanied by an enhanced phosphorylation of JNK, P38, ERK1/2, and IKKα/IKKβ. In addition, JNK and P38 inhibitors could significantly attenuate palmitate-induced mRNA expression of TNF-α and IL-6, respectively, whereas NF-κB inhibitor reduced the expression of both cytokines in palmitate-treated cells. Resveratrol pretreatment significantly prevented palmitate-induced TNF-α and IL-6 mRNA expression and protein secretion in C2C12 cells. Importantly, pre-treatment of the cells with resveratrol completely abrogated the phosphorylation of ERK1/2, JNK, and IKKα/IKKβ in palmitate treated cells. The protection from palmitate-induced inflammation by resveratrol was accompanied by a decrease in the generation of reactive oxygen species (ROS). N-acetyl cysteine (NAC), a known scavenger of ROS, could protect palmitate-induced expression of TNF-α and IL-6. Furthermore, inhibition of SIRT1 by shRNA or sirtinol demonstrated that the anti-inflammatory effect of resveratrol in muscle cells is mediated through a SIRT1-independent mechanism. Taken together, these findings suggest that resveratrol may represent a promising therapy for prevention of inflammation in skeletal muscle cells. J. Cell. Biochem. 118: 2654-2663, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Asie Sadeghi
- Faculty of Medicine, Department of Biochemistry, Tehran University of Medical Sciences, Tehran, I.R. Iran
| | | | - Abolfazl Golestani
- Faculty of Medicine, Department of Biochemistry, Tehran University of Medical Sciences, Tehran, I.R. Iran
| | - Reza Meshkani
- Faculty of Medicine, Department of Biochemistry, Tehran University of Medical Sciences, Tehran, I.R. Iran
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Hatoum D, Haddadi N, Lin Y, Nassif NT, McGowan EM. Mammalian sphingosine kinase (SphK) isoenzymes and isoform expression: challenges for SphK as an oncotarget. Oncotarget 2017; 8:36898-36929. [PMID: 28415564 PMCID: PMC5482707 DOI: 10.18632/oncotarget.16370] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/02/2017] [Indexed: 12/16/2022] Open
Abstract
The various sphingosine kinase (SphK) isoenzymes (isozymes) and isoforms, key players in normal cellular physiology, are strongly implicated in cancer and other diseases. Mutations in SphKs, that may justify abnormal physiological function, have not been recorded. Nonetheless, there is a large and growing body of evidence demonstrating the contribution of gain or loss of function and the imbalance in the SphK/S1P rheostat to a plethora of pathological conditions including cancer, diabetes and inflammatory diseases. SphK is expressed as two isozymes SphK1 and SphK2, transcribed from genes located on different chromosomes and both isozymes catalyze the phosphorylation of sphingosine to S1P. Expression of each SphK isozyme produces alternately spliced isoforms. In recent years the importance of the contribution of SpK1 expression to treatment resistance in cancer has been highlighted and, additionally, differences in treatment outcome appear to also be dependent upon SphK isoform expression. This review focuses on an exciting emerging area of research involving SphKs functions, expression and subcellular localization, highlighting the complexity of targeting SphK in cancer and also comorbid diseases. This review also covers the SphK isoenzymes and isoforms from a historical perspective, from their first discovery in murine species and then in humans, their role(s) in normal cellular function and in disease processes, to advancement of SphK as an oncotarget.
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Affiliation(s)
- Diana Hatoum
- School of Life Sciences, University of Technology Sydney, Ultimo, Sydney, NSW 2007, Australia
| | - Nahal Haddadi
- School of Life Sciences, University of Technology Sydney, Ultimo, Sydney, NSW 2007, Australia
| | - Yiguang Lin
- School of Life Sciences, University of Technology Sydney, Ultimo, Sydney, NSW 2007, Australia
| | - Najah T. Nassif
- School of Life Sciences, University of Technology Sydney, Ultimo, Sydney, NSW 2007, Australia
| | - Eileen M. McGowan
- School of Life Sciences, University of Technology Sydney, Ultimo, Sydney, NSW 2007, Australia
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