Figure 1.

DDR2 is induced during stellate cell activation in vitro. Stellate cells isolated from normal rat livers were maintained in monolayer culture for up to 8 days, and DDR2 mRNA and protein were analyzed. (a) Northern blot analysis performed with 10 μg mRNA from primary cultures of stellate cells hybridized to DDR2 and GAPDH cDNAs. (b) Summary histogram showing the induction of DDR2 during stellate cell activation by in vitro culture based on data from a. Results are expressed as a ratio of DDR2 mRNA versus GAPDH mRNA. (c) Stellate cells were cultured for 0, 2, and 8 days, lysed in RIPA buffer, immunoprecipitated, immunoblotted, and probed with the polyclonal anti-DDR2 Ab R2-JM. COS-1 cells were transfected with full-length DDR2 (+) or empty vector (–). (d) Lysates were also analyzed by Western blot for tubulin as a control for protein loading.