RSPOs facilitated HSC activation and promoted hepatic fibrogenesis.

// Xinguang Yin 1, 2 , Huixing Yi 3 , Linlin Wang 4 , Wanxin Wu 5 , Xiaojun Wu 2 , Linghua Yu 2 1 Centre for Gastroenterology and Hepatology, The Maternity and Child Health Care Hospital affiliated to Jiaxing College, Jiaxing, 314001, Zhejiang Province, PR China 2 Centre for Gastroenterology and Hepatology, The First Affiliated Hospital of Jiaxing College, Jiaxing, 314001, Zhejiang Province, PR China 3 Intensive Care Unit, The Second Affiliated Hospital of Zhejiang University, Hangzhou, 310009, Zhejiang Province, PR China 4 Department of Basic Medicine Sciences, School of Medicine, Zhejiang University, Hangzhou, 310058, China 5 Deparment of Pathology, The First Affiliated Hospital of Jiaxing College, Jiaxing, 314001, Zhejiang Province, PR China Correspondence to: Linghua Yu, email: yu.lh70s@gmail.com Keywords: RSPO, hepatic fibrosis, Wnt pathway, HSC Received: February 18, 2016      Accepted: August 24, 2016      Published: August 27, 2016 ABSTRACT Roof plate-specific spondin (RSPO) proteins are potent Wnt pathway agonists and involve in a broad range of developmental and physiological processes. This study investigated the activities and mechanisms of RSPOs in liver fibrogenesis, especially in hepatic stellate cell (HSC) activation. HSC activation was assessed by fibrosis biomarker (α-smooth muscle actin and Collagen-I), phenotypic change (accumulation of lipid droplets), and increased proliferation. Similarly, Wnt pathway activity was evaluated by the expression of nuclear β-catenin and T cell-specific transcription factors (TCF) activity. We found RSPOs were overexpressed in human fibrotic liver tissue and the expressions were correlated with liver fibrosis stages. In vitro studies showed RSPOs level increased during HSC activation, and stimuli with RSPOs enhanced Wnt pathway activity and promoted HSC activation subsequently. Furthermore, in vivo experiments demonstrated that the knockdown of RSPOs suppressed both Wnt pathway activity and HSC activation. Interestingly, the inhibitor of the Wnt signaling pathway Dickkopf1 impairs RSPOs effects on HSCs. Taken together, our results revealed that RSPOs facilitated HSC activation and promote liver fibrogenesis by enhancing the Wnt pathway.