Thrombin induces nestin expression via the transactivation of EGFR signalings in rat vascular smooth muscle cells.
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.
Huang
Yuan-Li
YL
Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei 106, Taiwan.
Shi
Guey-Yueh
GY
Lee
Hsinyu
H
Jiang
Meei-Jyh
MJ
Huang
Bu-Miin
BM
Wu
Hua-Lin
HL
Yang
Hsi-Yuan
HY
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
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