Vascular smooth muscle cells (VSMCs) phenotype switching plays an essential role in the pathogenesis of various vascular diseases. The present study aims to investigate the role of receptor-interacting protein kinases 1(RIPK1) in VSMCs phenotypic switching induced by Angiotensin Ⅱ(Ang Ⅱ). Expression of mRNA and protein of RIPK1, markers of VSMCs phenotypic switching and secretion, phosphorylation of the P65 subunit of NF-κB were measured by real-time PCR and Western blot. Meanwhile, EdU incorporation assay and wound scratch assay were performed to determine the cell proliferation and migration respectively. At the same time, Necrostatin-1(Nec-1, an known RIPK1 inhibitor) and RIPK1-specific small interference RNA (siRNA) were used to inhibit the expression of RIPK1. The experimental data demonstrated that the mRNA and protein levels of RIPK1 and P65 phosphorylation were increased significantly in the process of VSMC phenotypic switching induced by Ang II. Moreover, the expression of RIPK1 and P65 phosphorylation were significantly down-regulated in VSMCs pretreated with Nec-1 or trans-fected with RIPK1-siRNA. Furthermore, the proliferation, secretion and migration of VSMCs were also markedly suppressed after inhibition of RIPK1 by Nec-1 or its specific siRNA. The results suggested that RIPK1 might be involved in VSMC phenotypic switching induced by Ang II, which was possibly via up-regulating the NF-κB signaling pathway.
ObjectiveTo investigate the effect of ADAM33 gene silencing in VSMCs on the proliferation and lumen formation of airway vascular endothelial cells (VECs) in a co-culture system and the possible regulatory mechanism. MethodsThe Human aortic smooth muscle cells (HASMCs) and human pulmonary microvascular endothelial cells (HPMECs) were used to construct a cell co-culture system. ADAM33 gene expression was silenced by lentivirus transfection technique, and the subjects were divided into endothelial cell blank group, co-culture group, co-culture +shRNA negative control group, and co-culture + ADAM33-SHRNA group. The expressions of sADAM33, VEGFA,VEGER2, ang-1 and ang-2 in co-culture system were detected by ELISA. The proliferation and lumen formation of HPMECs were observed by CCK-8 and Transwell experiments. The protein expression of Tie2, PI3K, Akt, and mTOR key molecules in Tie2/PI3K/Akt/mTOR signaling pathway and the phosphorylation levels of AKT and mTOR were detected by Western-blotting method. Results① Compared with the co-culture group (0.851±0.036) and the co-culture + shRNA negative control group (0.828±0.047), the OD value of the co-culture + ADAM33shRNA group (0.699±0.038) was significantly decreased (P<0.05). ② Compared with the co-culture group (159.169±15.740) and the co-culture +shRNA negative control group (157.357±21.612), the tube length of the co-culture +ADAM33shRNA group (120.812±2.791) was also significantly decreased (P<0.05). ③ After ADAM33 gene expression of HASMCs was silted in co-culture system, the expression levels of VEGFA, VEGFR2, ang-1 and ang-2 were significantly decreased (P<0.05), while the expression levels of Tie2, PI3K, P-Akt and P-mtor were decreased (P<0.05). ConclusionsSilencing the expression of the ADAM33 gene could reduce the release of sADAM33 from the membrane of the airway VSMCs, regulate the proliferation and lumen formation of airway VECs by reducing the expression of VEGF/VEGFR and inhibiting the activities of the Tie2/PI3K/Akt/mTOR signaling pathways,and then participate in airway vascular remodeling in asthma.