[Role of R-Spondin1 in the activation of hepatic stellate cells].
OBJECTIVE
To investigate the role of R-Spondinl in the activation of hepatic stellate cells (HSCs).


METHODS
Twenty-four healthy male Kunming mice were randomly divided into the following two groups:fibrosis model group (n=16) and control group (n=8). Hepatic fibrosis was induced by subcutaneous injections of CC14 (20% in olive oil) at a dose of 5 ml/kg twice per week. After 10 weeks, the animals were sacrificed by CO(2) over-exposure and liver tissues were harvested.The protein and mRNA levels of R-Spondin1, alphat-SMA,and collagen I were examined by Western blot assay and real-time PCR respectively. Additionally,HSCs were isolated from the mice liver tissues to examine the time-series expression changes of R-Spondinl, alpha-SMA, and nuclear beta-catenin.TCF activity was analyzed by luciferase reporter assay.Moreover,HSCs were cocultured with recombinant R-Spondin1 and DKK1 to evaluate dose-response.


RESULTS
R-Spondinl expression was significantly higher in the fibrosis model group than in the control group (protein level:3.16 ± 0.18 vs. 0.99 ± 0.16, t =13.31, P < 0.01; mRNA level:4.36 ± 0.26 vs. 0.98 ± 0.12, t =21.46, P < 0.01).The culture-activated mouse HSCs showed up-regulated TCF activity (5.33 ± 0.34 vs. non-activated: 1.03 ± 0.09, t =20.93, P < 0.01), nuclear beta-catenin expression (4.47 ± 0.21 vs. 0.97 ± 0.14, t =25.25, P < 0.01), and R-Spondin1 expression (protein level: 4.54 ± 0.18 vs. 1.04 ± 0.12, t =31.17, P < 0.01; mRNA level:5.13 ± 0.15 vs. 1.01 ± 0.16, t=38.06, P < 0.01). Exogenous stimulation of freshly isolated mouse HSCs with recombinant R-Spondin1 induced a dose-dependent increase in both TCF activity and the expression of nuclear beta-catenin and alphat-SMA. DKK1 down-regulated activities of factors in the WNT signaling pathway and repressed activation of HSCs. Conclusion R-Spondin1 may promote HSC activation by enhancing the canonical WNT signaling pathway.
Department of Infectious Diseases, the First Hospital of Jiaxing, the First Affiliated Hospital of Jiaxing College, Jiaxing Zhejiang Province 314001, China.
Linghua
L
Yu
Wanxin
W
Wu
Xiaojun
X
Wu
Xiaowei
X
Wen
Xinguang
X
Yin
D000818:Animals; D015536:Down-Regulation; D016326:Extracellular Matrix Proteins; D055166:Hepatic Stellate Cells; D008103:Liver Cirrhosis; D008297:Male; D051379:Mice; D012333:RNA, Messenger; D060449:Wnt Signaling Pathway; D051176:beta Catenin
D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; D051176:beta Catenin