title: Cross talk among Smad, MAPK, and integrin signaling pathways enhances adventitial fibroblast functions activated by transforming growth factor-beta1 and inhibited by Gax.
abstract: OBJECTIVE
  We investigated whether Smad, mitogen-activated protein kinase (MAPK), and integrin signaling pathways cross-talk to enhance adventitial fibroblast (AF) bioactivity, which was activated by transforming growth factor (TGF)-beta1 and inhibited by Gax.
  
  
  RESULTS
  Cultured AFs were stimulated with Ad-Gax, TGF-beta1, and siRNA-Gax. Assays for AFs viabilities demonstrated that TGF-beta1 and siRNA-Gax enhanced AFs proliferative, migratory, and adherent abilities, whereas Gax counteracted TGF-beta1-activated actions. Flow cytometry revealed that TGF-beta1 and siRNA-Gax increased S phase cells; however, Gax decreased AFs in the S phase and increased those in the G0-G1 and apoptotic phases. RT-PCR, Western blotting, and immunocytochemistry showed that TGF-beta1 and siRNA-Gax upregulated the expression of cytokines in Smad, MAPK, and integrin signaling pathways, and downregulated that of p15, p16, and p21. Conversely, Gax induced downregulation of these cytokines and upregulation of p15, p16, and p21. Thus, these signaling pathways cross-talk to enhance AF bioactivity; Gax effectively counteracts TGF-beta1 effects, blocks the cross-talk of these pathways, inhibits AF functions, and increases AF apoptosis.
  
  
  CONCLUSIONS
  Our findings indicate that cross-talk among Smad, MAPK, and integrin signaling pathways may account mainly for the mechanism of AF functions. Gax is a promising therapeutic gene for dissecting the signaling pathways controlling AF bioactivities.
authors.affiliation: Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Shandong University Qilu Hospital, Jinan, Shandong, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Jin Bo
authors.initials: JB
authors.lastname: Feng
authors.forename: Yu Xia
authors.initials: YX
authors.lastname: Zhao
authors.forename: Xu Ping
authors.initials: XP
authors.lastname: Wang
authors.forename: Jian Min
authors.initials: JM
authors.lastname: Yang
authors.forename: Ming Xiang
authors.initials: MX
authors.lastname: Zhang
authors.forename: Xing Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000378:metabolism; D001483:Base Sequence; D049109:Cell Proliferation; D002478:Cells, Cultured; D003238:Connective Tissue / Q000378:metabolism; D003239:Connective Tissue Cells / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005347:Fibroblasts / Q000378:metabolism; D005822:Genetic Vectors; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011817:Rabbits; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D051785:Smad Proteins / Q000378:metabolism*; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; D016023:Integrins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1