In genome wide e pression profiling, we found that 70% of genes selectively induced by cyclic stretch rela ation of SMC in vitro were similarly up regulated by PDGF treatment. In that study, C D informatics analysis revealed AP 1 as the transcription fac tor most significantly customer reviews associated with stretch induced gene e pression. We proceeded to demonstrate that mechan ical injury of the bladder promoted rapid phosphorylation of the PDGF receptor, independently of e ogenous ligand, to promote up regulation of the AP 1 target thrombomo dulin. Together, these observations suggest a mechan ism underlying convergence of mechanical and growth factor signaling that involves PDGF receptor activation.

Among the overlapping genes and proteins identi fied in the current study as significantly enriched in re sponse to PDGF treatment, CYR61, HMO 1 and C CL12 emerged as genes linked to biological processes relevant to tissue remodeling, i. e. proliferation, migration and mo tility. Elevated C CL12 and CYR61 have been implicated in fibroproliferative responses of vascular SMC and fibro cytes in arterial and airway remodeling, whereas CYR61 is elevated in hypertrophic smooth muscle of the bladder wall secondary to outlet obstruction and following cyclic stretch rela ation of bladder SMC in vitro. Conversely, up regulation of HMO 1 has been reported to attenuate both mitogen induced proliferation and migration of SMC in vitro, as well as smooth muscle remodeling in response to hypo ic injury. In the current study, CYR61, HMO 1 and C CL12 were also linked to the process of angiogenesis.

A similar angiogenesis focused gene signature was identified by Yang and colleagues in SMC e posed to mechanical stretch. In that study AP 1, EGR 1 and MYB were identified as putative transcriptional regulators of the mechanosensitive transcriptional program, in agreement with our current and prior findings. Al though MYC itself was not identified, the Brefeldin_A MYC family members upstream regulatory factor 1 and USF2 were implicated as putative transcriptional regulators in both studies that evaluated stretch induced gene e pres sion in bladder SMC. USF1 and USF2 bind to E bo motifs in target gene promoters and antagonize MYC activity. Notably, USF1 and USF2 have been shown to directly up regulate transcription of HMO 1 in vitro and in vivo. Our current findings showing that PDGF induced downregulation of HMO 1 in visceral SMC was reversed by pharmacologic inhibition of MYC is consistent with negative regulation of HMO 1 e pression by MYC and with its antagonistic interaction with USF1 2 at target gene regulatory regions. E posure of hollow or gans Y-27632 supplier to mechanical stress in vivo induces transient hypo ia, as a result of vascular compression, which in turn enhances blood flow.