Fig. 7

Graphic brief shows that how signal pathway of CXCL12 stimulates expression of connective tissue growth factor (CTGF) in human lung fibroblasts. It was previously revealed that the Rac1/extracellular signal-regulated kinase (ERK)-dependent activator protein (AP)-1 pathway participated in CXCL12-caused expression of CTGF in WI-38 cells. In this report, CXCL12 also activated the mitogen-activated protein kinase kinase kinase 1 (MEKK1) signaling pathway, which turned on c-Jun N-terminal kinase (JNK) and SMAD3 activation and finally caused expression of CTGF in human lung fibroblasts (WI-38)