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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2009;29:1594.)
© 2009 American Heart Association, Inc.

Cell Biology/Signaling

Thrombin Induces EGF Receptor Expression and Cell Proliferation via a PKC()/c-Src-Dependent Pathway in Vascular Smooth Muscle Cells

Hsi-Lung Hsieh; Wei-Hsuan Tung; Cheng-Ying Wu; Hui-Hsin Wang; Chih-Chung Lin; Tze-Shyuan Wang; Chuen-Mao Yang

From the Department of Nursing, Division of Basic Medical Sciences (H.-L.H.), Chang Gung Institute of Technology; the Department of Pharmacology (W.-H.T., C.-Y.W., H.-H.W., T.-S.W., C.-M.Y.) Chang Gung University; and the Department of Anesthetics (C.-C.L.), Chang Gung University and Chang Gung Memorial Hospital, Kwei-San, Tao-Yuan, Taiwan.

Correspondence to Chuen-Mao Yang, Department of Pharmacology, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-San, Tao-Yuan, Taiwan. E-mail chuenmao{at}mail.cgu.edu.tw

Objection— Thrombin upregulates expression of several proteins in vascular smooth muscle cells (VSMCs) which may contribute to atherosclerosis. Here, we investigated the mechanisms underlying thrombin-induced EGF receptor (EGFR) expression and its effect on VSMCs.

Methods and Results— Normal rat VSMCs were used. First, Western blotting and RT-PCR analyses showed that thrombin induces the expression of EGFR at transcription and translation levels in VSMCs. Second, pharmacological inhibitors, dominant negative mutants, and short hairpin RNA interference (shRNA) technology enabled us to demonstrate that thrombin-induced EGFR expression is mediated through PKC()/c-Src-dependent transactivation of EGFR linking to PI3K/Akt and ERK1/2. We further investigated whether the transcription factors AP-1 and NF-B are involved in this response by a promoter assay. Finally, data obtained by using EGFR shRNA technology and XTT assay demonstrated that thrombin-enhanced VSMC proliferation was mediated through upregulation of EGFR.

Conclusions— Our results demonstrate that thrombin-enhanced VSMC proliferation was mediated through upregulation of EGFR via a PKC()/c-Src-dependent transactivation of EGFR, PI3K-Akt, and ERK, and AP-1/NF-B pathway.

In this study, we investigated the mechanisms underlying thrombin-regulated EGF receptor (EGFR) expression and its effect on VSMCs. Our results demonstrated that thrombin-enhanced VSMC proliferation is mediated through upregulation of EGFR via a PKC()/c-Src-dependent transactivation of EGFR, PI3K-Akt, and -ERK, and AP-1/NF-B pathway.

Key Words: thrombin • EGF receptor • ERK1/2 • proliferation • vascular smooth muscle cells