title: Thrombin-induced CCN2 expression in human lung fibroblasts requires the c-Src/JAK2/STAT3 pathway.
abstract: Thrombin is a multifunctional serine protease and an important fibrotic mediator that induces CCN2 expression. We previously showed that thrombin induces CCN2 expression via an ASK1-dependent JNK/AP-1 pathway in human lung fibroblasts. In this study, we further investigated the roles of c-Src, JAK2, and STAT3 in thrombin-induced CCN2 expression. Thrombin-induced CCN2 expression and CCN2-Luc activity were attenuated by a JAK inhibitor (AG490) and JAK2DN, STAT3DN, and the STAT decoy ODN. Moreover, transfection of cells with a CCN2-mtSTAT-Luc construct inhibited thrombin-induced CCN2-Luc activity. Treatment of cells with thrombin caused JAK2 phosphorylation at Tyr1007/1008 and STAT3 phosphorylation at Tyr705 in time-dependent manners. Thrombin-induced STAT3 phosphorylation was inhibited by AG490 and JAK2DN. Thrombin-induced STAT3 binding to the CCN2 promoter was analyzed by a DNA-binding affinity pull-down assay. In addition, thrombin-induced CCN2 expression and CCN2-Luc activity were inhibited by c-SrcDN and PP2 (an Src inhibitor). Transfection of cells with c-SrcDN also inhibited thrombin-induced JAK2 and STAT3 phosphorylation. Taken together, these results indicate that thrombin might activate c-Src to induce JAK2 activation, which in turn, causes STAT3 activation, and finally induces CCN2 expression in human lung fibroblasts.
authors.affiliation: College of Medicine, Taipei Medical University, 250 Wu-Hsing St., Taipei, Taiwan.
authors.forename: Kua-Jen
authors.initials: KJ
authors.lastname: Bai
authors.forename: Bing-Chang
authors.initials: BC
authors.lastname: Chen
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Pai
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Weng
authors.forename: Chung-Chi
authors.initials: CC
authors.lastname: Yu
authors.forename: Ming-Jen
authors.initials: MJ
authors.lastname: Hsu
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Yu
authors.forename: Hon-Ping
authors.initials: HP
authors.lastname: Ma
authors.forename: Chih-Hsiung
authors.initials: CH
authors.lastname: Wu
authors.forename: Chuang-Ye
authors.initials: CY
authors.lastname: Hong
authors.forename: Min-Liang
authors.initials: ML
authors.lastname: Kuo
authors.forename: Chien-Huang
authors.initials: CH
authors.lastname: Lin
mesh_terms: D015153:Blotting, Western; D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D055513:Connective Tissue Growth Factor / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013917:Thrombin / Q000378:metabolism; D014162:Transfection; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: C526317:CCN2 protein, human; D050796:STAT3 Transcription Factor; D055513:Connective Tissue Growth Factor; D000081247:CSK Tyrosine-Protein Kinase; D053614:Janus Kinase 2; D019061:src-Family Kinases; C000631346:CSK protein, human; D013917:Thrombin