标题：Ubiquitin Carboxyl Terminal Hydrolyase L1-Suppressed Autophagic Degradation of p21(WAF1/Cip1) as a Novel Feedback Mechanism in the Control of Cardiac Fibroblast Proliferation
作者：Zhang, Xiaoming; Guo, Linlin; Niu, Ting; Shao, Lei; Li, Huanjie; Wu, Weiwei; Wang, Wenjuan; Lv, Linmao; Qin, Qingyun; Wang, Fang; 更多 作者机构：[Zhang, Xiaoming; Guo, Linlin; Niu, Ting; Shao, Lei; Li, Huanjie; Wu, Weiwei; Wang, Wenjuan; Lv, Linmao; Qin, Qingyun; Wang, Fang; Tang, Dongqi; Wang, 更多
通讯作者地址：[Wang, XL]Shandong Univ, Qilu Hosp, Res Ctr Cell Therapy, Key Lab Cardiovasc Remodeling & Funct Res, Jinan 250100, Shandong, Peoples R China.
摘要：Aims: Deubiquitinating enzymes (DUBs) appear to be critical regulators of a multitude of processes such as proliferation, apoptosis, differentiation, and inflammation; however, the potential roles of DUBs in the heart remain to be determined. This study was aimed to explore the role of a DUB, ubiquitin carboxyl terminal hydrolyase L1 (UCH-L1) in maladaptive cardiac remodeling and dysfunction.; Methods and Results: Maladaptive cardiac remodeling and dysfunction were induced in mice by transverse aortic constriction (TAC). UCH-L1 expression was transiently increased and then declined near to the basal level while impairment of cardiac function proceeded. The upregulation of UCH-L1 was observed in cardiac myocytes and fibroblasts. In primary culture of cardiac fibroblasts, UCH-L1 was upregulated by platelet-derived growth factor (PDGF)-BB and PDGF-DD. Adenoviral overexpession of UCH-L1 inhibited the PDGF-induced cardiac fibroblast proliferation without affecting the activation of mitogen activated protein kinases (MAPKs), Akt, and signal transducers and activators of transcription 3 (STAT3). Further signaling dissection revealed that PDGF-BB posttranscriptional upregulated p21(WAF1/Cip1) protein expression, which was inhibited by rapamycin, an activator of autophagy via suppressing mammalian target of rapamycin (mTOR), rather than MG132, a proteasome inhibitor. Overexpression of UCH-L1 enhanced PDGF-BB-induced mTOR phosphorylation and upregulation of p21(WAF1/Cip1) protein expression while suppressed autophagic flux in cardiac fibroblasts.; Conclusion: UCH-L1 facilitates PDGF-BB-induced suppression of autophagic degradation of p21(WAF1/Cip1) proteins in cardiac fibroblasts, which may serve as a novel negative feedback mechanism in the control of cardiac fibroblast proliferation contributing to cardiac fibrosis and dysfunction.