Berberine suppresses MEK/ERK-dependent Egr-1 signaling pathway and inhibits vascular smooth muscle cell regrowth after in vitro mechanical injury.
Vascular smooth muscle cell (SMC) proliferation plays an important role in the pathogenesis of atherosclerosis and post-angioplasty restenosis. Berberine is a well-known component of the Chinese herb medicine Huanglian (Coptis chinensis), and is capable of inhibiting SMC contraction and proliferation, yet the exact mechanism is unknown. We therefore investigated the effect of berberine on SMC growth after mechanic injury in vitro. DNA synthesis and cell proliferation assay were performed to show that berberine inhibited serum-stimulated rat aortic SMC growth in a concentration-dependent manner. Mechanical injury with sterile pipette tip stimulated the regrowth of SMCs. Treatment with berberine prevented the regrowth and migration of SMCs into the denuded trauma zone. Western blot analysis showed that activation of the MEK1/2 (mitogen-activated protein kinase kinase 1/2), extracellular signal-regulated kinase (ERK), and up-regulation of early growth response gene (Egr-1), c-Fos and Cyclin D1 were observed sequentially after mechanic injury in vitro. Semi-quantitative reverse-transcription PCR assay further confirmed the increase of Egr-1, c-Fos, platelet-derived growth factor (PDGF) and Cyclin D1 expression in a transcriptional level. However, berberine significantly attenuated MEK/ERK activation and downstream target (Egr-1, c-Fos, Cyclin D1 and PDGF-A) expression after mechanic injury in vitro. Our study showed that berberine blocked injury-induced SMC regrowth by inactivation of ERK/Egr-1 signaling pathway thereby preventing early signaling induced by injury in vitro. The anti-proliferative properties of berberine may be useful in treating disorders due to inappropriate SMC growth.
Liang
Kae-Woei
KW
Institute of Clinical Medicine and Department of Medicine, National Yang-Ming University, Taipei, Taiwan.
Ting
Chih-Tai
CT
Yin
Sui-Chu
SC
Chen
Ying-Tsung
YT
Lin
Shing-Jong
SJ
Liao
James K
JK
Hsu
Shih-Lan
SL
D000818:Animals; D001013:Aorta, Thoracic; D001599:Berberine / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000293:injuries / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects*
D004365:Drugs, Chinese Herbal; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D001599:Berberine; D004247:DNA; D048049:Extracellular Signal-Regulated MAP Kinases; D019950:Mitogen-Activated Protein Kinase 1