R-spondin2 activates hepatic stellate cells and promotes liver fibrosis.
BACKGROUND
The development of liver fibrosis is the fundamental stage toward a number of mortal complications of liver diseases, including cirrhosis and hepatocellular carcinoma. Canonical Wnt pathway is crucial in diverse biological processes and mediates the progression and regression of liver fibrosis. As a potent Wnt pathway agonist, the role of roof plate-specific spondin-2 (R-Spondin2) in the hepatic fibrosis has not been well elucidated.


OBJECTIVE
The purpose of this study was to investigate whether R-Spondin2 contributes to hepatic stellate cells (HSCs) activation, the key event in liver fibrogenesis.


METHODS
Human liver tissues, hepatic fibrosis mouse model, and freshly isolated mice HSCs were used. Protein expression and transcriptional level were analyzed by Western-blot assays and real-time PCR, respectively. Exogenous stimulation with recombinant R-Spondin2 and knockdown of R-Spondin2 were performed to investigate functionality. Nuclear β-catenin level and T cell-specific transcription factors activity were analyzed, and HSC proliferation was tested by MTT assay.


RESULTS
Overexpression of R-Spondin2 was observed in both human fibrotic liver tissues and hepatic fibrosis mouse model. Exogenous stimulation with R-Spondin2 in the freshly isolated mice HSCs induced a dose-dependent increase in Wnt pathway activities, HSC proliferation, and the expression of α-smooth muscle actin (α-SMA) and Collagen I. Additionally, Wnt pathway activities, HSC proliferation, and the expressions of α-SMA and Collagen I decreased in the R-Spondin2 knockdown HSCs.


CONCLUSIONS
These findings suggest that R-Spondin2 may promote HSC activation by enhancing the canonical Wnt pathway.
Department of Gastroenterology, The First Affiliated Hospital of Jiaxing College, 1882 Central-South Road, Jiaxing, 314001, Zhejiang Province, People's Republic of China, jxyyyxg@sina.com.
Xinguang
X
Yin
Huixing
H
Yi
Wanxin
W
Wu
Jing
J
Shu
Xiaojun
X
Wu
Linghua
L
Yu
D000818:Animals; D002252:Carbon Tetrachloride Poisoning / Q000473:pathology; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000378:metabolism*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019699:Thrombospondins / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin; D000098907:R-Spondins
D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D019699:Thrombospondins; D051176:beta Catenin; C518904:RSPO2 protein, mouse; D000098907:R-Spondins; C557408:Rspo2 protein, human