RESUMO
INTRODUCTION: Obesity has been believed to be closely linked with many kinds of diseases including atherosclerosis, hypertension, cerebrovascular thrombosis, and diabetes. Ghrelin and Homeobox transcript antisense RNA (HOTAIR) were believed to be involved in the regulation of myocardial injury. METHODS: The obesity mice model was established through feeding mice (C57BL/6J, male, eight-week-old) with high-fat diet and palmitate (PA)-induced cardiomyocyte injury. RNA and protein levels were detected with Quantitative real-time PCR and Western blotting. The levels of TG, TCH, LDL, CK-MB, cTnl, and BNP in the serum or cell medium supernatant were measured using ELISA kits. The ROS level was detected with the DCFH-DA method. Binding sites between different targets were identified using detection of dual luciferase reporter assay. Cell apoptosis was analyzed by flow cytometry. RNA-binding protein immunoprecipitation and chromatin immunoprecipitation were used to detect the binding of DNMT3B with HOTAIR or miR-196b promoter. RESULTS: The expression of HOTAIR was downregulated, and miR-196b was upregulated in the obese myocardial injury. Ghrelin attenuated PA-induced cardiomyocyte injury by increasing HOTAIR. HOTAIR regulated the expression of miR-196b by recruiting DNMT3B to induce methylation of the miR-196b gene promoter. The binding site between miR-196b and IGF-1 was identified. DISCUSSION/CONCLUSION: We demonstrated that ghrelin attenuated PA-induced cardiomyocyte injury by regulating the HOTAIR/miR-196b/IGF-1 signaling pathway. Our findings might provide novel thought for the prevention and treatment of obesity-induced myocardial injury by targeting HOTAIR/miR-196b.
Assuntos
Grelina , MicroRNAs , RNA Longo não Codificante , Animais , Epigênese Genética , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Obesidade/complicações , Obesidade/genética , RNA Longo não Codificante/genéticaRESUMO
BACKGROUND: Obesity is associated with the impairment of cardiac fitness and consequent ventricular dysfunction and heart failure. Ghrelin has been largely documented to be cardioprotective against ischaemia/reperfusion injury. However, the role of ghrelin in obesity-induced myocardial injury is largely unknown. This study sought to determine the cardiac effect of ghrelin against obesity-induced injury and the underlying mechanisms. METHODS: The effect of ghrelin was evaluated in a mouse model of obesity and a palmitic acid (PA)-treated cardiomyocyte cell line with or without ghrelin transfection. Gene and protein expression levels were determined by real-time PCR and western blot, respectively. Cell apoptosis was measured by flow cytometry analysis. RESULTS: In the present study, we found that both a high-fat diet (HFD) and PA treatment caused myocardial injury by increasing apoptosis and the expression of inflammatory cytokines. Overexpression of ghrelin reversed the effects induced by HFD or PA treatment. Knockdown of lncRNA H19 or overexpression of miR-29a abrogated the cardioprotective effects of ghrelin against apoptosis and inflammation. We also found that IGF-1 was a target gene of miR-29a and that H19 regulated IGF-1 expression via miR-29a. Overexpression of IGF-1 partially reversed the apoptosis and inflammation promoting effects of miR-29a. CONCLUSIONS: Our findings suggested that ghrelin protected against obesity-induced myocardial injury by regulating the H19/miR-29a/IGF-1 signalling axis, providing further evidence for the clinical application of ghrelin.
Assuntos
Grelina/genética , Traumatismos Cardíacos/genética , Fator de Crescimento Insulin-Like I/genética , MicroRNAs/genética , RNA Longo não Codificante/genética , Animais , Apoptose/genética , Linhagem Celular , Modelos Animais de Doenças , Regulação da Expressão Gênica/genética , Traumatismos Cardíacos/etiologia , Traumatismos Cardíacos/patologia , Humanos , Camundongos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Obesidade/complicações , Obesidade/genética , Obesidade/patologia , Transdução de Sinais/genética , TransfecçãoRESUMO
OBJECTIVE: To study the relationship between insertion/deletion (I/D) polymorphism of 287 bp in the 16th intron of angiotensin converting enzyme (ACE) and essential hypertension in children. METHODS: I/D polymorphism of 287 bp in the 16th intron of ACE was detected using PCR in 105 children with essential hypertension and 105 normal children as control group. RESULTS: There was an I/D polymorphism in the 16th intron of ACE in the hypertension and the control groups: type II, type ID and type DD. The genotype frequencies of type DD, type ID and type II in the hypertension group were 30.5%, 47.6% and 21.9%, respectively. The genotype frequencies of type DD, type ID and type II in the control group were 14.3%, 46.7% and 39.1%, respectively. There were significant differences in the genotype frequencies of types DD and II between the two groups (P<0.01). The allele frequency of type D (54.3% vs 37.6%) was significantly higher in the hypertension group; in contrast, the allele frequency of type I (45.7% vs 62.4%) was significantly lower than in the control group (P<0.01). CONCLUSIONS: Polymorphism of type II, type ID and type DD exits in ACE. The deletion of 287 bp in the 16th intron of ACE might be associated with the occurrence of essential hypertension in children.