1
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Wadie W, Ahmed GS, Shafik AN, El-Sayed M. Effects of insulin and sitagliptin on early cardiac dysfunction in diabetic rats. Life Sci 2022; 299:120542. [PMID: 35395243 DOI: 10.1016/j.lfs.2022.120542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/23/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
AIMS Cardiac affection is common in diabetic patients. Although insulin exerts a cardioprotective role, it may not be enough to totally prevent this affection. The current study aimed to compare the cardioprotective effect of insulin alone or combined with sitagliptin in a rat model of type 1 diabetes mellitus. MATERIALS AND METHODS Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ; 60 mg/kg). Diabetic rats were treated with insulin (3 IU), insulin (6 IU), or insulin (3 IU) + sitagliptin (10 mg/kg) for 42 days. KEY FINDINGS Diabetic rats exhibited significant systolic and diastolic cardiac affection with significant elevation of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6) and brain natriuretic peptide (BNP) levels. Treatment with insulin prevented the deterioration of diabetes-induced cardiac condition, an effect that was significantly potentiated by the combined use of sitagliptin. SIGNIFICANCE The combined use of sitagliptin and insulin significantly improved the cardioprotective effect of insulin and prevented the early cardiac dysfunction in STZ diabetic rats.
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Affiliation(s)
- Walaa Wadie
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
| | - Gehad S Ahmed
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Amani N Shafik
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mohamed El-Sayed
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, Cairo, Egypt
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2
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Liu X, Song F, Liu C, Zhang Y. 25-OH-PPD inhibits hypertrophy on diabetic cardiomyopathy via the PI3k/Akt/GSK-3β signaling pathway. Exp Ther Med 2020; 20:2141-2147. [PMID: 32765689 PMCID: PMC7401478 DOI: 10.3892/etm.2020.8893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 03/11/2020] [Indexed: 12/24/2022] Open
Abstract
The present study investigated the inhibitory effects and the associated mechanism of the compound 25-OH-PPD (PPD) on cardiac hypertrophy, fibrosis and inflammation. The signaling pathways associated with diabetic mellitus cardiomyopathy (DMCM) were investigated using a rat model. DMCM Sprague-Dawley rats were induced by injection of streptozotocin. The animals were divided into 5 groups as follows: Normal group (NG group), diabetic group, PPD treatment group, PPD/LY294002 group (inhibitor of PI3K/Akt) and PPD/LiCl group [inhibitor of glycogen synthase kinase (GSK) 3β]. The studies were carried out during the 12 weeks following induction of diabetes and the levels of plasma brain natriuretic peptide (BNP), creatine phosphokinase isoenzyme (CK-MB) were measured. In addition, the volume of myocardial collagen fraction (CVF) was tested. The expression levels of the inflammatory cytokines, including transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), cell adhesion molecules α-smooth muscle actin (α-SMA) and vascular adhesion molecule 1 (VCAM-1) and associated signaling proteins (Akt, GSK-3β) were measured by biochemical analyses. The levels of BNP and CK-MB, the volume of CVF, the expression levels of TGF-β1, CTGF, α-SMA and VCAM-1 in the diabetic group were higher compared with those of the normal control group (P<0.05). Conversely, the levels of these molecules were significantly decreased in the PPD treatment groups (P<0.05). The aforementioned effects were partially eliminated in the PPD/LY294002 and PPD/LiCl groups. In addition, PPD treatment significantly increased the expression levels of p-Akt and decreased the levels of phosphorylated GSK-3β compared with those of the DMCM group (P<0.05). The data demonstrated that the protective effects of 25-OH-PPD against DMCM may be attributed to the PI3k/Akt/GSK-3β signaling pathway, via the suppression of the α-SMA/VCAM axis and the downregulation of TGF-β1 and CTGF expression.
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Affiliation(s)
- Xinyu Liu
- Department of Pharmacology, Jinzhou Medical University, Jinzhou, Liaoning 120001, P.R. China
| | - Feiran Song
- Department of Gynecology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Chunna Liu
- Department of Pharmacology, Jinzhou Medical University, Jinzhou, Liaoning 120001, P.R. China
| | - Yi Zhang
- Department of Gynecology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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3
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Chatterjee A, Barnard J, Moravec C, Desnoyer R, Tirupula K, Karnik SS. Connective tissue growth factor dependent collagen gene expression induced by MAS agonist AR234960 in human cardiac fibroblasts. PLoS One 2017; 12:e0190217. [PMID: 29287092 PMCID: PMC5747466 DOI: 10.1371/journal.pone.0190217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/11/2017] [Indexed: 12/11/2022] Open
Abstract
Perspectives on whether the functions of MAS, a G protein-coupled receptor, are beneficial or deleterious in the heart remain controversial. MAS gene knockout reduces coronary vasodilatation leading to ischemic injury. G protein signaling activated by MAS has been implicated in progression of adaptive cardiac hypertrophy to heart failure and fibrosis. In the present study, we observed increased expression of MAS, connective tissue growth factor (CTGF) and collagen genes in failing (HF) human heart samples when compared to non-failing (NF). Expression levels of MAS are correlated with CTGF in HF and NF leading to our hypothesis that MAS controls CTGF production and the ensuing expression of collagen genes. In support of this hypothesis we show that the non-peptide MAS agonist AR234960 increases both mRNA and protein levels of CTGF via ERK1/2 signaling in HEK293-MAS cells and adult human cardiac fibroblasts. MAS-mediated CTGF expression can be specifically blocked by MAS inverse agonist AR244555 and also by MEK1 inhibition. Expression of CTGF gene was essential for MAS-mediated up-regulation of different collagen subtype genes in HEK293-MAS cells and human cardiac fibroblasts. Knockdown of CTGF by RNAi disrupted collagen gene regulation by the MAS-agonist. Our data indicate that CTGF mediates the profibrotic effects of MAS in cardiac fibroblasts. Blocking MAS-CTGF-collagen pathway should be considered for pharmacological intervention for HF.
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Affiliation(s)
- Arunachal Chatterjee
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Zoology, Acharya Jagadish Chandra Bose College, Kolkata, West Bengal, India
| | - John Barnard
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Christine Moravec
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Russell Desnoyer
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Kalyan Tirupula
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Sadashiva S. Karnik
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- * E-mail:
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4
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Ying C, Liu T, Ling H, Cheng M, Zhou X, Wang S, Mao Y, Chen L, Zhang R, Li W. Glucose variability aggravates cardiac fibrosis by altering AKT signalling path. Diab Vasc Dis Res 2017; 14:327-335. [PMID: 28301953 DOI: 10.1177/1479164117698917] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVE To study the effect of blood glucose variability on cardiac fibrosis and its mechanism in a model of diabetic cardiomyopathy. METHODS A total of 45 Sprague Dawley rats were randomly divided into three groups: control, control diabetes mellitus and fluctuated blood glucose groups. Fluctuated blood glucose was induced by daily subcutaneous insulin and intraperitoneal glucose injections at different time points. Blood lipids and glycosylated haemoglobin A1c were assessed. Super oxide dismutase activity and malondialdehyde level in rat heart homogenates were determined by assay kit. Structural cardiac tissue changes were observed by haematoxylin and eosin staining and Masson's trichrome staining. Collagen type 3, fibronectin, phosphorylated Ser/Thr protein kinase, phosphorylated glycogen synthase kinase-3 beta, glycogen synthase kinase-3 beta, nuclear factor kappa-light-chain-enhancer of activated B cells, cleaved-cysteinyl aspartate-specific proteinase-3 (caspase-3) and tumour necrosis factor-α levels were determined by western blot. RESULTS Compared with the control group, cardiac fibrosis and oxidative stress in heart tissue were aggravated in diabetic rats, which were more pronounced in glucose variability rats. However, the expression levels of AKT and glycogen synthase kinase-3 beta were not significantly different in three groups, but the expression levels of phosphorylated Ser/Thr protein kinase and phosphorylated glycogen synthase kinase-3 beta were significantly decreased in the control diabetes mellitus and fluctuated blood glucose groups compared to control group, and levels in the fluctuated blood glucose group were significantly less than in the control diabetes mellitus group. In addition, the expression levels of nuclear factor kappa B and caspase-3 in both the control diabetes mellitus and fluctuated blood glucose groups were higher than in the control group, with the highest levels measured in the fluctuated blood glucose group. CONCLUSION Blood glucose variability can aggravate heart tissue fibrosis, possibly involving oxidative stress by inhibiting AKT signalling path.
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Affiliation(s)
- Changjiang Ying
- 1 Department of Endocrinology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Ting Liu
- 2 The Graduate School, Xuzhou Medical University, Xuzhou, China
| | - Hongwei Ling
- 1 Department of Endocrinology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Mingyue Cheng
- 3 Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Xiaoyan Zhou
- 4 Laboratory of Morphology, Xuzhou Medical University, Xuzhou, China
| | - Shanshan Wang
- 2 The Graduate School, Xuzhou Medical University, Xuzhou, China
| | - Yizhen Mao
- 2 The Graduate School, Xuzhou Medical University, Xuzhou, China
| | - Lei Chen
- 2 The Graduate School, Xuzhou Medical University, Xuzhou, China
| | | | - Wei Li
- 1 Department of Endocrinology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
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5
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Yang F, Li B, Dong X, Cui W, Luo P. The beneficial effects of zinc on diabetes-induced kidney damage in murine rodent model of type 1 diabetes mellitus. J Trace Elem Med Biol 2017; 42:1-10. [PMID: 28595780 DOI: 10.1016/j.jtemb.2017.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus is a chronic multi-factorial metabolic disorder resulting from impaired glucose homeostasis. Zinc is a key co-factor for the correct functioning of anti-oxidant enzymes. Zinc deficiency therefore, impairs their synthesis, leading to increased oxidative stress within cells. Zinc deficiency occurs commonly in diabetic patients. The aim of this study is to investigate the effects of varying concentrations of zinc on diabetic nephropathy (DN) and the underlying mechanisms involved. FVB male mice aged 8 weeks were injected intraperitoneally with multiple low-dose streptozotocin at a concentration of 50mg/kg body weight daily for 5 days. Diabetic and age-matched control mice were treated with special diets supplemented with zinc at varying concentrations (0.85mg/kg, 30mg/kg, 150mg/kg) for 3 months. The mice were fed with zinc diets to mimic the process of oral administration of zinc in human. Zinc deficiency to some extent aggravated the damage of diabetic kidney. Feeding with normal (30mg/kg zinc/kg diet) and especially high (150mg/kg zinc/kg diet) concentration zinc could protect the kidney against diabetes-induced damage. The beneficial effects of zinc on DN are achieved most likely due to the upregulation of Nrf2 and its downstream factors NQO1, SOD1, SOD2. Zinc upregulated the expression of Akt phosphorylation and GSK-3β phosphorylation, resulting in a reduction in Fyn nuclear translocation and export of Nrf2 to the cytosol. Thus, regular monitoring and maintaining of adequate levels of zinc are recommended in diabetic individuals in order to delay the development of DN.
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Affiliation(s)
- Fan Yang
- The Department of Nephropathy, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Bing Li
- The Department of Nephropathy, Jilin Province People's Hospital, Changchun China
| | - Xiaoming Dong
- The Department of Orthopaedics, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Wenpeng Cui
- The Department of Nephropathy, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China
| | - Ping Luo
- The Department of Nephropathy, The Second Hospital of Jilin University, 218 Ziqiang Street, Changchun 130041, China.
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6
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Xu Y, Zhou H, Zhu Q. The Impact of Microbiota-Gut-Brain Axis on Diabetic Cognition Impairment. Front Aging Neurosci 2017; 9:106. [PMID: 28496408 PMCID: PMC5406474 DOI: 10.3389/fnagi.2017.00106] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/31/2017] [Indexed: 12/11/2022] Open
Abstract
Progressive cognitive dysfunction is a central characteristic of diabetic encephalopathy (DE). With an aging population, the incidence of DE is rising and it has become a major threat that seriously affects public health. Studies within this decade have indicated the important role of risk factors such as oxidative stress and inflammation on the development of cognitive impairment. With the recognition of the two-way communication between gut and brain, recent investigation suggests that “microbiota-gut-brain axis” also plays a pivotal role in modulating both cognition function and endocrine stability. This review aims to systemically elucidate the underlying impact of diabetes on cognitive impairment.
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Affiliation(s)
- Youhua Xu
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau
| | - Hua Zhou
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau.,Laboratory for Bioassay and Molecular Pharmacology of Chinese Medicines, Macau Institute for Applied Research in Medicine and HealthTaipa, Macau
| | - Quan Zhu
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau.,Laboratory for Bioassay and Molecular Pharmacology of Chinese Medicines, Macau Institute for Applied Research in Medicine and HealthTaipa, Macau.,Guangdong Consun Pharmaceutical Group, Institute of Consun Co. for Chinese Medicine in Kidney DiseasesGuangzhou, China
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7
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Yu J, Liu C, Li Z, Zhang C, Wang Z, Liu X. Inhibitory effects and mechanism of 25-OH-PPD on glomerular mesangial cell proliferation induced by high glucose. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 44:93-98. [PMID: 27135372 DOI: 10.1016/j.etap.2016.04.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 04/18/2016] [Accepted: 04/23/2016] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To investigate the protective effects and potential mechanism of the compound 25-OH-PPD (PPD) on the glomerular mesangial cells (GMC) under high glucose condition. METHODS The hypertrophic GMC cells were established by DMEM containing glucose and randomly divided into five groups, including the normal control group (Control), the high glucose model group (HG, 25 mmolL(-1)), the PPD low dose group (1μmolL(-1), PPD-L), the PPD middle dose group (5μmolL(-1), PPD -M) and the PPD high dose group (10μmolL(-1), UCN-H). The GMC were incubated for 48h under different treatment factors. Total protein content was determined by Lowry method. The diameter of the single GMC and volume were measured by computer photograph analysis system. The GMC cell viability was analyzed by MTT assay. The level of malondialdehyde (MDA), the content of glutathione (GSH) and superoxide dismutase (SOD) activity were measured by ELISA. [Ca(2+)]і transient was measured by Till image system and by cell-loading Fura-2/AM. The expression of COX-1 and COX-2 were also determined using ELISA method. RESULTS The viability of GMC and the total protein content were decreased in HG group, different dosage PPD group could increase these indexes (P<0.05). The level of MDA was increased, the content of GSH and SOD was decreased in HG group, while PPD could reduce the MDA and enhance GSH and SOD (P<0.05). Following treatment with different dosage (PPD-L, PPD-M or PPD-H), the [Ca(2+)]і transient was reduced (P<0.05 or P<0.01). Moreover, the expression of COX-1 was decreased while COX-2 expression was increased in different dosage PPD groups. CONCLUSION The protective effects of PPD on GMC from HG-induced hypertrophy may be associated with the inhibition of [Ca(2+)]і transient and decreasing expression of COX-1 via the oxidative-stress injure pathway.
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Affiliation(s)
- Junxian Yu
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
| | - Chunna Liu
- Department of Pharmacology, Liaoning Medical University, JinZhou 121001, China
| | - Zhe Li
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
| | - Chao Zhang
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
| | - Zheng Wang
- Department of Pharmacy, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
| | - Xinyu Liu
- The First Affiliated Hospital of Liaoning Medical University, JinZhou 121001, China.
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8
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FTY720 (Gilenya) treatment prevents spontaneous autoimmune myocarditis and dilated cardiomyopathy in transgenic HLA-DQ8-BALB/c mice. Cardiovasc Pathol 2016; 25:353-61. [PMID: 27288745 PMCID: PMC5372700 DOI: 10.1016/j.carpath.2016.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/13/2016] [Accepted: 05/13/2016] [Indexed: 02/06/2023] Open
Abstract
Although dilated cardiomyopathy (DCM) is often caused by viral infections, it frequently involves autoimmune mechanisms associated with particular HLA-DR and DQ alleles. Our homozygous HLA-DQ8Ab(0) transgenic mice in the BALB/c background (HLA-DQ8(BALB/c)-Tg) developed early and progressive fatal heart failure from 4 to 5 weeks of age. Clinical signs of the disease included cyanotic eyes, tachycardia with dyspnea (from pale to cyanotic limbs), and terminal whole body edema. Sick mice had extremely dilated hearts, enlarged liver and spleen, and pleural/peritoneal effusion. Histology of the heart showed extensive heart muscle destruction with signs of fibrosis. The autoimmune nature of the disease was shown by high titers of antimyosin antibodies in the sera and IgG deposits in sick heart muscles, as well as focal neutrophil, T cell, and macrophage infiltration of the heart muscle. The sera of the sick mice showed a granular staining pattern on sections of healthy heart muscle. Quantitative analyses of DCM-specific gene expression studies revealed that sets of genes are involved in inflammation, hypoxia, and fibrosis. Treatment with FTY720 (Fingolimod/Gilenya) protected animals from the development of cardiomyopathy. HLA-DQ8(BALB/c)-Tg mice represent a spontaneous autoimmune myocarditis model that may provide a useful tool for studying the autoimmune mechanism of DCM and testing immunosuppressive drugs.
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9
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He J, Quintana MT, Sullivan J, L Parry T, J Grevengoed T, Schisler JC, Hill JA, Yates CC, Mapanga RF, Essop MF, Stansfield WE, Bain JR, Newgard CB, Muehlbauer MJ, Han Y, Clarke BA, Willis MS. MuRF2 regulates PPARγ1 activity to protect against diabetic cardiomyopathy and enhance weight gain induced by a high fat diet. Cardiovasc Diabetol 2015; 14:97. [PMID: 26242235 PMCID: PMC4526192 DOI: 10.1186/s12933-015-0252-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/30/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In diabetes mellitus the morbidity and mortality of cardiovascular disease is increased and represents an important independent mechanism by which heart disease is exacerbated. The pathogenesis of diabetic cardiomyopathy involves the enhanced activation of PPAR transcription factors, including PPARα, and to a lesser degree PPARβ and PPARγ1. How these transcription factors are regulated in the heart is largely unknown. Recent studies have described post-translational ubiquitination of PPARs as ways in which PPAR activity is inhibited in cancer. However, specific mechanisms in the heart have not previously been described. Recent studies have implicated the muscle-specific ubiquitin ligase muscle ring finger-2 (MuRF2) in inhibiting the nuclear transcription factor SRF. Initial studies of MuRF2-/- hearts revealed enhanced PPAR activity, leading to the hypothesis that MuRF2 regulates PPAR activity by post-translational ubiquitination. METHODS MuRF2-/- mice were challenged with a 26-week 60% fat diet designed to simulate obesity-mediated insulin resistance and diabetic cardiomyopathy. Mice were followed by conscious echocardiography, blood glucose, tissue triglyceride, glycogen levels, immunoblot analysis of intracellular signaling, heart and skeletal muscle morphometrics, and PPARα, PPARβ, and PPARγ1-regulated mRNA expression. RESULTS MuRF2 protein levels increase ~20% during the development of diabetic cardiomyopathy induced by high fat diet. Compared to littermate wildtype hearts, MuRF2-/- hearts exhibit an exaggerated diabetic cardiomyopathy, characterized by an early onset systolic dysfunction, larger left ventricular mass, and higher heart weight. MuRF2-/- hearts had significantly increased PPARα- and PPARγ1-regulated gene expression by RT-qPCR, consistent with MuRF2's regulation of these transcription factors in vivo. Mechanistically, MuRF2 mono-ubiquitinated PPARα and PPARγ1 in vitro, consistent with its non-degradatory role in diabetic cardiomyopathy. However, increasing MuRF2:PPARγ1 (>5:1) beyond physiological levels drove poly-ubiquitin-mediated degradation of PPARγ1 in vitro, indicating large MuRF2 increases may lead to PPAR degradation if found in other disease states. CONCLUSIONS Mutations in MuRF2 have been described to contribute to the severity of familial hypertrophic cardiomyopathy. The present study suggests that the lack of MuRF2, as found in these patients, can result in an exaggerated diabetic cardiomyopathy. These studies also identify MuRF2 as the first ubiquitin ligase to regulate cardiac PPARα and PPARγ1 activities in vivo via post-translational modification without degradation.
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Affiliation(s)
- Jun He
- Department of Pathology and Laboratory Medicine, University of North Carolina, 111 Mason Farm Road, MBRB 2340B, Chapel Hill, NC, USA. .,General Hospital of Ningxia Medical University, Yinchuan, Ningxia, People's Republic of China.
| | - Megan T Quintana
- Department of Surgery, University of North Carolina, Chapel Hill, NC, USA.
| | - Jenyth Sullivan
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA.
| | - Traci L Parry
- McAllister Heart Institute, University of North Carolina, 111 Mason Farm Road, MBRB 2340B, Chapel Hill, NC, USA.
| | - Trisha J Grevengoed
- Department of Nutrition, University of North Carolina, Chapel Hill, NC, USA.
| | - Jonathan C Schisler
- McAllister Heart Institute, University of North Carolina, 111 Mason Farm Road, MBRB 2340B, Chapel Hill, NC, USA. .,Department of Pharmacology, University of North Carolina, Chapel Hill, NC, USA.
| | - Joseph A Hill
- Department of Internal Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Cecelia C Yates
- Department of Health Promotions and Development, School of Nursing, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Rudo F Mapanga
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch, 7600, South Africa.
| | - M Faadiel Essop
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch, 7600, South Africa.
| | | | - James R Bain
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA. .,Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University Medical Center, Durham, NC, USA.
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA. .,Division of Endocrinology, Metabolism, and Nutrition, Department of Medicine, Duke University Medical Center, Durham, NC, USA.
| | - Michael J Muehlbauer
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA.
| | - Yipin Han
- East Chapel Hill High School, Chapel Hill, NC, USA.
| | - Brian A Clarke
- Novartis, Novartis Institutes for BioMedical Research, Inc., 400 Technology Square, Boston, MA, 601-4214, USA.
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina, 111 Mason Farm Road, MBRB 2340B, Chapel Hill, NC, USA. .,McAllister Heart Institute, University of North Carolina, 111 Mason Farm Road, MBRB 2340B, Chapel Hill, NC, USA.
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