RESUMO
Homeostatic control of vascular smooth muscle cell (VSMC) differentiation is critical for contractile activity and regulation of blood flow. Recently, we reported that precontracted blood vessels are relaxed and the phenotype of VSMC is regulated from a synthetic to contractile state by glucose-6-phosphate dehydrogenase (G6PD) inhibition. In the current study, we investigated whether the increase in the expression of VSMC contractile proteins by inhibition and knockdown of G6PD is mediated through a protein kinase G (PKG)-dependent pathway and whether it regulates blood pressure. We found that the expression of VSMC-restricted contractile proteins, myocardin (MYOCD), and miR-1 and miR-143 are increased by G6PD inhibition or knockdown. Importantly, RNA-sequence analysis of aortic tissue from G6PD-deficient mice revealed uniform increases in VSMC-restricted genes, particularly those regulated by the MYOCD-serum response factor (SRF) switch. Conversely, expression of Krüppel-like factor 4 (KLF4) is decreased by G6PD inhibition. Interestingly, the G6PD inhibition-induced expression of miR-1 and contractile proteins was blocked by Rp-ß-phenyl-1,N2-etheno-8-bromo-guanosine-3',5'-cyclic monophosphorothioate, a PKG inhibitor. On the other hand, MYOCD and miR-143 levels are increased by G6PD inhibition through a PKG-independent manner. Furthermore, blood pressure was lower in the G6PD-deficient compared with wild-type mice. Therefore, our results suggest that the expression of VSMC contractile proteins induced by G6PD inhibition occurs via PKG1α-dependent and -independent pathways.
Assuntos
Aorta/metabolismo , Proteínas Contráteis/genética , Proteína Quinase Dependente de GMP Cíclico Tipo I/metabolismo , Glucosefosfato Desidrogenase/antagonistas & inibidores , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Animais , Aorta/efeitos dos fármacos , Western Blotting , Bovinos , Cromatografia Líquida , Proteínas Contráteis/efeitos dos fármacos , Proteínas Contráteis/metabolismo , Proteína Quinase Dependente de GMP Cíclico Tipo I/antagonistas & inibidores , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Técnicas de Silenciamento de Genes , Glucosefosfato Desidrogenase/genética , Imunoprecipitação , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/efeitos dos fármacos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , MicroRNAs/efeitos dos fármacos , MicroRNAs/genética , Músculo Liso Vascular/citologia , Músculo Liso Vascular/efeitos dos fármacos , Miócitos de Músculo Liso/efeitos dos fármacos , Proteínas Nucleares/efeitos dos fármacos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase , Ratos , Fator de Resposta Sérica/efeitos dos fármacos , Fator de Resposta Sérica/genética , Fator de Resposta Sérica/metabolismo , Espectrometria de Massas em Tandem , Transativadores/efeitos dos fármacos , Transativadores/genética , Transativadores/metabolismoRESUMO
Exercise and heart disease both induce cardiac remodeling, but only disease causes fibrosis and compromises heart function. The cardioprotective benefits of exercise have been attributed to changes in cardiomyocyte physiology, but the impact of exercise on cardiac fibroblasts (CFs) is unknown. Here, RNA-sequencing reveals rapid divergence of CF transcriptional programs during exercise and disease. Among the differentially expressed programs, NRF2-dependent antioxidant genes - including metallothioneins (Mt1 and Mt2) - are induced in CFs during exercise and suppressed by TGF-ß/p38 signaling in disease. In vivo, mice lacking Mt1/2 exhibit signs of cardiac dysfunction in exercise, including cardiac fibrosis, vascular rarefaction, and functional decline. Mechanistically, exogenous MTs derived from fibroblasts are taken up by cultured cardiomyocytes, reducing oxidative damage-dependent cell death. Importantly, suppression of MT expression is conserved in human heart failure. Taken together, this study defines the acute transcriptional response of CFs to exercise and disease and reveals a cardioprotective mechanism that is lost in disease.