CBP knockdown inhibits angiotensin II-induced vascular smooth muscle cells proliferation through downregulating NF-kB transcriptional activity.
CREB binding protein (CBP), a powerful transcriptional co-activator for various transcriptional factors, regulates cell behavior in many cell types. Angiotensin II (Ang II) contributes to vascular lesion by promoting vascular smooth muscle cells (VSMCs) proliferation and migration. Therefore, we examined whether CBP knockdown could suppress Ang II-induced VSMCs proliferation, and elucidated its underlying molecular mechanism. We constructed lentiviral vector expressing CBP-specific short hairpin RNAs (shRNAs) that efficiently silenced CBP. VSMCs proliferation was evaluated by bromodeoxyuridine (BrdU) incorporation assay. Protein and mRNA expression of CBP and relevant cytokines were examined by Western blot, ELISA, and real-time PCR, respectively. We also used luciferase reporter gene and electrophoretic mobility shift assay (EMSA) to detect Nuclear factor kappaB (NF-kB) transcriptional activity and DNA binding. Meanwhile, NF-kB p65 subunit nuclear translocation was confirmed by immunoblotting. Lentiviral-mediated CBP-shRNAs at different multiplicities of infection (MOI = 100, 150) both significantly suppressed Ang II-induced CBP expression. Knockdown of CBP markedly inhibited Ang II-stimulated VSMCs proliferation and cytokines (TNF-alpha and IL-6) production. However, this inhibitory effect was not enhanced at MOI of 150 compared with MOI of 100 (P > 0.05). CBP siRNA showed the potent inhibition on Ang II-induced NF-kB transcriptional activity. Similarly, no significant difference was found between CBP siRNA lentivirus treatment groups. Furthermore, CBP gene silencing had no effect on NF-kB nuclear translocation and DNA binding. These findings suggest that CBP knockdown inhibits Ang II-induced VSMCs proliferation and the mechanism is involved with downregulation of NF-kB transcriptional activity, not through reduction in NF-kB nuclear translocation or DNA binding. Maintaining proper CBP level may be a potential therapeutic target for Ang II-induced cardiovascular disorders.
Yang
Jian
J
Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei Province, China.
Jiang
Hong
H
Chen
Si-si
SS
Chen
Jing
J
Xu
Sheng-kai
SK
Li
Wan-qiang
WQ
Wang
Ji-chun
JC
D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D001013:Aorta, Thoracic / Q000378:metabolism / Q000473:pathology; D015153:Blotting, Western; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D002478:Cells, Cultured; D015536:Down-Regulation; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D055785:Gene Knockdown Techniques; D005822:Genetic Vectors; D015850:Interleukin-6 / Q000378:metabolism; D016086:Lentivirus / Q000235:genetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015850:Interleukin-6; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000804:Angiotensin II; D050882:CREB-Binding Protein; C494365:Crebbp protein, rat