RESUMO
Transcriptional co-activator with PDZ-binding motif (TAZ) and Yes-associated protein (YAP) are critical transcriptional co-activators downstream of the Hippo pathway involved in the regulation of organ size, tissue regeneration, proliferation, and apoptosis. Recent studies suggested common and distinct functions of TAZ and YAP and their diverse impact under several pathological conditions. Here we report differential regulation of TAZ and YAP in response to oxidative stress. H2O2 exposure leads to increased stability and activation of TAZ but not of YAP. H2O2 induces reversible S-glutathionylation at conserved cysteine residues within TAZ. We further demonstrate that TAZ S-glutathionylation is critical for reactive oxygen species (ROS)-mediated, TAZ-dependent TEA domain transcription factor (TEAD) trans-activation. Lysophosphatidic acid, a physiological activator of YAP and TAZ, induces ROS elevation and, subsequently, TAZ S-glutathionylation, which promotes TAZ-mediated target gene expression. TAZ expression is essential for renal homeostasis in mice, and we identify basal TAZ S-glutathionylation in murine kidney lysates, which is elevated during ischemia/reperfusion injury in vivo This induced nuclear localization of TAZ and increased expression of connective tissue growth factor. These results describe a novel mechanism by which ROS sustains total cellular levels of TAZ. This preferential regulation suggests TAZ to be a redox sensor of the Hippo pathway.
Assuntos
Cisteína/metabolismo , Glutationa/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Traumatismo por Reperfusão/metabolismo , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Animais , Western Blotting , Proteínas de Ciclo Celular , Células Cultivadas , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Cisteína/química , Glutationa/química , Via de Sinalização Hippo , Peróxido de Hidrogênio/farmacologia , Técnicas Imunoenzimáticas , Imunoprecipitação , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Proteínas Nucleares/genética , Oxidantes/farmacologia , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Serina-Treonina Quinases/genética , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Transdução de Sinais/efeitos dos fármacos , Transativadores/genética , Fatores de Transcrição/genética , Proteínas com Motivo de Ligação a PDZ com Coativador TranscricionalRESUMO
OBJECTIVE: The incretin hormones GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic peptide) are secreted by the gut after food intake leading to pancreatic insulin secretion and glucose lowering. Beyond its role in glucose control, GLP-1 was found in mice and men to beneficially modulate the process of atherosclerosis, which has been linked to improved cardiovascular outcome of patients with diabetes at high cardiovascular risk treated with GLP-1 receptor agonists. However, little is known on the role of the other main incretin in the cardiovascular system. The aim of this study was to characterize GIP in atherosclerotic cardiovascular disease. METHODS AND RESULTS: Serum concentrations of GIP were assessed in 731 patients who presented for elective coronary angiography at the University Hospital Aachen. While GIP concentrations were not associated with coronary artery disease (CAD), we found 97 patients with PAD (peripheral artery disease) vs. 634 without PAD to have higher circulating GIP levels (413.0 ± 315.3 vs. 332.7 ± 292.5 pg/mL, p = 0.0165). GIP levels were independently related to PAD after multivariable adjustment for CAD, age, sex, BMI, hypertension, diabetes, CRP, WBC, and smoking. To investigate the functional relevance of elevated GIP levels in human atherosclerotic disease, we overexpressed GIP (1-42) in ApoE-/- mice fed a Western diet for 12 weeks using an adeno-associated viral vector system. GIP overexpression led to reduced atherosclerotic plaque macrophage infiltration and increased collagen content compared to control (LacZ) with no change in overall lesion size, suggesting improved plaque stability. Mechanistically, we found GIP treatment to reduce MCP-1-induced monocyte migration under In vitro conditions. Additionally, GIP prevented proinflammatory macrophage activation leading to reduced LPS-induced IL-6 secretion and inhibition of MMP-9 activity, which was attributable to GIP dependent inhibition of NfκB, JNK-, ERK, and p38 in endotoxin activated macrophages. CONCLUSION: Elevated concentrations of the incretin hormone GIP are found in patients with atherosclerotic cardiovascular disease, while GIP treatment attenuates atherosclerotic plaque inflammation in mice and abrogates inflammatory macrophage activation in vitro. These observations identified GIP as a counterregulatory vasoprotective peptide, which might open new therapeutic avenues for the treatment of patients with high cardiovascular risk.