SCG10 expression on activation of hepatic stellate cells promotes cell motility through interference with microtubules.

During liver fibrogenesis, quiescent hepatic stellate cells switch their phenotype toward a myofibroblastic-like pattern with a gain in motility. Here, we show that SCG10 (superior cervical ganglia 10) mRNA expression, a microtubule-destabilizing protein that favors cell growth and motility in neurons, both increases and correlates with the stage of fibrosis in patients with chronic hepatitis C. We also show the de novo expression of SCG10 mRNA in two rat models of liver fibrosis. We demonstrate that activated hepatic stellate cells appear to be the major cellular sources of SCG10 in the liver. Tracking of the SCG10 pathway in hepatic stellate cells shows that SCG10 initially accumulates in the perinuclear Golgi area then migrates in small vesicle-like structures along individual microtubules. Moreover, SCG10 vesicles cluster at the distal ends of microtubules in areas where tubules are spread and decompacted, suggesting their preferential association with destabilized and dynamic microtubules. Inhibition of SCG10 expression by gene-specific short interfering RNA in primary rat hepatic stellate cells is associated with a significant reduction in microtubule-dependent cellular functions, such as proliferation and migration. In conclusion, the de novo expression of SCG10 by hepatic stellate cells may play a major role in cellular mechanisms associated with HSC activation, namely cell motility and division, through interference with microtubules. SCG10 may represent a potential molecular target for anti-fibrosis therapies.