title: Thrombin induces nestin expression via the transactivation of EGFR signalings in rat vascular smooth muscle cells.
abstract: Regulation of nestin gene expression is largely unknown despite that it is widely used as a progenitor cell marker. In this study, we showed that nestin expression is regulated by the thrombin-mediated EGFR transactivation in serum-deprived primary cultures of rat vascular smooth muscle cells (VSMCs). This resulted from the direct binding of thrombin to PAR-1 rather than indirectly affecting through the binding to thrombomodulin, as demonstrated by thrombomodulin RNAi. In this process, the PAR-1-induced c-Src plays a critical role through two routes; one was the direct intracellular phosphorylation of EGFR and the other was the extracellular activation of the MMP-2-mediated shedding of HB-EGF. The transactivated EGFR then led to the downstream Ras-Raf-ERK signaling axis, but not the p38 or JNK pathways. In addition, the EMSA experiment showed that the transcriptional factor Sp1 is critical for the thrombin-induced nestin expression in rat VSMCs. Furthermore, RNAi of nestin attenuated the thrombin-induced cell proliferation, indicating that thrombin-induced nestin expression and cell proliferation share the same EGFR transactivation mechanism. This study also suggested that nestin may play an important role in cell proliferation induced by the thrombin-mediated EGFR transactivation.
authors.affiliation: Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan.
authors.forename: Yuan-Li
authors.initials: YL
authors.lastname: Huang
authors.forename: Guey-Yueh
authors.initials: GY
authors.lastname: Shi
authors.forename: Hsinyu
authors.initials: H
authors.lastname: Lee
authors.forename: Meei-Jyh
authors.initials: MJ
authors.lastname: Jiang
authors.forename: Bu-Miin
authors.initials: BM
authors.lastname: Huang
authors.forename: Hua-Lin
authors.initials: HL
authors.lastname: Wu
authors.forename: Hsi-Yuan
authors.initials: HY
authors.lastname: Yang
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D016895:Culture Media, Serum-Free; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D064231:Nestin; D014176:Protein Biosynthesis / Q000187:drug effects; D051381:Rats; D044463:Receptor, PAR-1 / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects*; D048490:raf Kinases / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D016895:Culture Media, Serum-Free; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577486:Nes protein, rat; D064231:Nestin; D044463:Receptor, PAR-1; D043562:Receptors, G-Protein-Coupled; D016329:Sp1 Transcription Factor; D066246:ErbB Receptors; D019061:src-Family Kinases; D048490:raf Kinases; D013917:Thrombin; D018631:ras Proteins