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[en] Highlights: • Telmisartan treatment alleviates insulin resistance in adipocytes stimulated with TNFα. • Telmisartan treatment reduces phosphorylation of PPARγ in adipocytes stimulated with TNFα. • Telmisartan treatment regulates the expressions of PPARγ downstream genes. • Telmisartan treatment promotes the secretion of adiponectin in adipocytes. Telmisartan is an angiotensin II receptor blocker (ARB) and a partial agonist of peroxisome proliferator activated receptor γ (PPARγ). It has been shown to significantly enhance insulin sensitivity in clinical studies and in vitro experiments. However, the effect of telmisartan on PPARγ in adipocytes remains unknown.
[en] The rat posterodorsal medial amygdala (MePD) links emotionally charged sensory stimuli to social behavior, and is part of the supramedullary control of the cardiovascular system. We studied the effects of microinjections of neuroactive peptides markedly found in the MePD, namely oxytocin (OT, 10 ng and 25 pg; n=6/group), somatostatin (SST, 1 and 0.05 μM; n=8 and 5, respectively), and angiotensin II (Ang II, 50 pmol and 50 fmol; n=7/group), on basal cardiovascular activity and on baroreflex- and chemoreflex-mediated responses in awake adult male rats. Power spectral and symbolic analyses were applied to pulse interval and systolic arterial pressure series to identify centrally mediated sympathetic/parasympathetic components in the heart rate variability (HRV) and arterial pressure variability (APV). No microinjected substance affected basal parameters. On the other hand, compared with the control data (saline, 0.3 µL; n=7), OT (10 ng) decreased mean AP (MAP_5_0) after baroreflex stimulation and increased both the mean AP response after chemoreflex activation and the high-frequency component of the HRV. OT (25 pg) increased overall HRV but did not affect any parameter of the symbolic analysis. SST (1 μM) decreased MAP_5_0, and SST (0.05 μM) enhanced the sympathovagal cardiac index. Both doses of SST increased HRV and its low-frequency component. Ang II (50 pmol) increased HRV and reduced the two unlike variations pattern of the symbolic analysis (P<0.05 in all cases). These results demonstrate neuropeptidergic actions in the MePD for both the increase in the range of the cardiovascular reflex responses and the involvement of the central sympathetic and parasympathetic systems on HRV and APV
[en] Highlights: • RNF146 is accumulated in nucleus in response to angiotensin II. • The nuclear export of RNF146 is mediated by XPO1 in endothelial cells. • Angiotensin II-induced nuclear accumulation of RNF146 is due to the loss of XPO1 expression level. • The protective effect of RNF146 against endothelial cell injury is dependent on XPO1-mediated nuclear export. Endothelial cells death induced by angiotensin II (Ang II) plays a role in vascular injury. RNF146 is identified as a E3 ubiquitin ligase, which promotes cell survival under many types of stresses. However, the role of RNF146 in endothelial cellular injury is unknown. In human umbilical vein endothelial cells (HUVECs), Ang II treatment led to cell death by oxidative stress and promoted RNF146 to accumulate in nucleus in time dependent manner. Nuclear export signal was found in the RNF146's sequence. The interaction between RNF146 and XPO1 was further confirmed by co-immunoprecipitation. Inhibition of XPO1 with KPT-185 increased the level of RNF146 in nucleus. The expression of XPO1 was suppressed responding to Ang II treatment. Overexpression of XPO1 facilitated the nuclear shuttling of RNF146, which protected from Ang II-induced cell death. Moreover, overexpression of RNF146 in HUVECs reduced the cell death induced by Ang II, whereas inhibition of XPO1 abolished the protective effect of RNF146. Therefore, our data demonstrated that RNF146 was a protective factor against cell death induced by AngII in human endothelial cells, which was dependent on XPO1-mediated nuclear export.
[en] Angiotensin II (AngII) is the most important component of angiotensin, which has been regarded as a major contributor to the incidence of hypertension and vascular endothelial dysfunction. The adipocytokine C1q/TNF-related protein 6 (CTRP6) was recently reported to have multiple protective effects on cardiac and cardiovascular function. However, the exact role of CTRP6 in the progression of AngII induced hypertension and vascular endothelial function remains unclear. Here, we showed that serum CTRP6 content was significantly downregulated in SHRs, accompanied by a marked increase in arterial systolic pressure and serum AngII, CRP and ET-1 content. Then, pcDNA3.1-mediated CTRP6 delivery or CTRP6 siRNA was injected into SHRs. CTRP6 overexpression caused a significant decrease in AngII expression and AngII-mediated hypertension and vascular endothelial inflammation. In contrast, CTRP6 knockdown had the opposite effect to CTRP6 overexpression. Moreover, we found that CTRP6 positively regulated the activation of the ERK1/2 signaling pathway and the expression of peroxisome proliferator-activated receptor γ (PPARγ), a recently proven negative regulator of AngII, in the brain and vascular endothelium of SHRs. Finally, CTRP6 was overexpressed in endothelial cells, and caused a significant increase in PPARγ activation and suppression in AngII-mediated vascular endothelial dysfunction and apoptosis. The effect of that could be rescued by the ERK inhibitor PD98059. In contrast, silencing CTRP6 suppressed PPARγ activation and exacerbated AngII-mediated vascular endothelial dysfunction and apoptosis. In conclusion, CTRP6 improves PPARγ activation and alleviates AngII-induced hypertension and vascular endothelial dysfunction. - Highlights: • Serum CTRP6 was significantly decreased in spontaneously hypertensive rats (SHRs). • CTRP6 positively regulated the activation of the ERK1/2 signaling pathway. • CTRP6 negatively regulates PPARγ mediated Angiotensin II (AngII) expression. • CTRP6 alleviates AngII-induced hypertension and vascular endothelial dysfunction.
[en] Advances in the knowledge of renal neoplasms have demonstrated the implication of several proteases in their genesis, growth and dissemination. Glutamyl-aminopeptidase (GAP) (EC. 188.8.131.52) is a zinc metallopeptidase with angiotensinase activity highly expressed in kidney tissues and its expression and activity have been associated wtih tumour development. In this prospective study, GAP spectrofluorometric activity and immunohistochemical expression were analysed in clear-cell (CCRCC), papillary (PRCC) and chromophobe (ChRCC) renal cell carcinomas, and in renal oncocytoma (RO). Data obtained in tumour tissue were compared with those from the surrounding uninvolved kidney tissue. In CCRCC, classic pathological parameters such as grade, stage and tumour size were stratified following GAP data and analyzed for 5-year survival. GAP activity in both the membrane-bound and soluble fractions was sharply decreased and its immunohistochemical expression showed mild staining in the four histological types of renal tumours. Soluble and membrane-bound GAP activities correlated with tumour grade and size in CCRCCs. This study suggests a role for GAP in the neoplastic development of renal tumours and provides additional data for considering the activity and expression of this enzyme of interest in the diagnosis and prognosis of renal neoplasms
[en] Highlights: • ATRAP as a negative regulator of AT1 receptor plays an inhibitory role in VSMCs proliferation both in vitro and in vivo. • ATRAP triggers the marked apoptosis of VSMCs in balloon-injuried carotid arteries and depresses neointimal formation. • ATRAP induces VSMCs apoptosis through the influence of the PI3K/Akt signaling pathway. Intimal hyperplasia is the main cause of restenosis after carotid artery injury, and the underlying mechanism involves the proliferation and migration of vascular smooth muscle cells (VSMCs). Angiotensin II Type 1 Receptor-Associated Protein (ATRAP) has been reported to withstand intimal hyperplasia by inhibiting VSMCs proliferation and migration; however, whether the beneficial effect of ATRAP associates with VSMCs apoptosis remains unclarified. We demonstrated that the adenoviral-mediated overexpression of ATRAP induced VSMC apoptosis, alleviating the balloon injury-induced neointima formation in rats. Under the condition of Angiotensin-II stimulation, ATRAP overexpression induced the apoptosis of rat VSMCs by depressing the PI3K-Akt signaling; whereas up-regulation of Akt by PTEN inhibitor abolished the apoptotic death. Thus, ATRAP regulates carotid intimal hyperplasia through controlling the PI3K-Akt signal-mediated VSMCs apoptosis.
[en] Angiotensin II (Ang II), the main effector of the renin angiotensin system, acts upon two distinct transmembrane receptors, the Ang II type 1 and the type 2 (AT_2-) receptor, to induce promotion and inhibition of ERK2 phosphorylation. The AT_2-receptor, through an interaction with its putative signaling partner MTUS1/ATIP (AT_2-receptor interacting protein), inhibits the mitogenic effects of EGF in prostate cancer cell lines representing both early and late stage disease. This is the first report on the expression of ATIP in normal and malignant human prostatic biopsies. The expression of ATIP and its major isoforms, ATIP1 and ATIP3, in normal prostatic cells and three prostate cancer cell lines was examined using QPCR and immunohistochemistry. Human biopsies containing benign prostatic hyperplasia (BPH), high grade prostatic intraepithelial neoplasia (HGPIN) and well, moderately and poorly differentiated prostate cancer were also examined. Overall, ATIP1 and ATIP3 mRNA expression was increased in malignant compared to normal tissues and cell lines. ATIP immunostaining was low or absent in both the basal and columnar epithelial cell layers surrounding BPH acini; however, it was observed in high concentration in neoplastic epithelial cells of HGPIN and was clearly evident in cytoplasms of malignant cells in all prostate cancer grades. ATIP immunostaining was also identified in the cytoplasms of LNCaP and PC3 prostate cancer cells. As the AT_2-receptor/ATIP inhibitory signaling pathway exists in malignant cells in all grades of prostate cancer, enhancement of this pathway may be a therapeutic target even after the development of androgen-independence
[en] To evaluate the renin-angiotensin-aldosterone system in diabetes mellitus, basal plasma renin activity (PRA) and its response to intravenous furosemide were determined in 40 diabetic subjects. The diabetics were divided into 4 groups according to the presence of nephropathy and/or hypertension. Uncomplicated diabetics (Group I) were taken as control group and the results of the other groups were compared to this group. In diabetics with nephropathy alone (Group II), and with nephropathy and hypertension (Group III), basal PRA values were 0.63±0.59 ng/ml/hr., and 0.79±0.62 ng/ml/hr., respectively, both significantly lower than control group. (1.53±1.09 ng/ml/hr.). (p<0.05) In both of the above groups, the responses to intravenous furosemide tended to be blunted. On the other hand, in diabetics, with hypertension only (Group IV), the basal and stimulated PRA were not significantly different from control. Above results suggests that nephropathy may be one of the factors which suppress renin activity in diabetes mellitus