Angiotensin II-induced histone deacetylase 5 phosphorylation, nuclear export, and Egr-1 expression are mediated by Akt pathway in A10 vascular smooth muscle cells.
Angiotensin II (ANG II) regulates an array of physiological and pathological responses in vascular smooth muscle cells (VSMCs) by activating ERK1/2 and phosphoinositide 3-kinase (PI3K)/Akt signaling pathways. We have demonstrated that ANG II and insulin-like growth factor-1 (IGF-1) induce the expression of early growth response protein-1 (Egr-1), a zinc finger transcription factor, which regulates the transcription of cell cycle regulatory genes network in VSMCs. We have reported that IGF-1 induces the phosphorylation of histone deacetylase 5 (HDAC5), which has been implicated in the expression of genes linked to VSMC growth and hypertrophy, via a PI3K/Akt-dependent pathway in VSMCs. However, the involvement of PI3K/Akt pathways in ANG II-induced HDAC5 phosphorylation and the contribution of HDAC5 in Egr-1 expression and hypertrophy in VSMCs remain unexplored. Here, we show that pharmacological blockade of the PI3K/Akt pathway either by wortmannin/SC66 or siRNA-induced silencing of Akt attenuated ANG II-induced HDAC5 phosphorylation and its nuclear export. Moreover, SC66 or Akt knockdown also suppressed ANG II-induced Egr-1 expression. Furthermore, pharmacological inhibition of HDAC5 by MC1568 or TMP-195 or knockdown of HDAC5 and the blockade of the nuclear export of HDAC5 by leptomycin B or KPT-330 significantly reduced ANG II-induced Egr-1 expression. In addition, depletion of either HDAC5 or Egr-1 by siRNA attenuated VSMC hypertrophy in response to ANG II. In summary, our results demonstrate that ANG II-induced HDAC5 phosphorylation and its nuclear exclusion are mediated by PI3K/Akt pathway and HDAC5 is an upstream regulator of Egr-1 expression and hypertrophy in VSMCs.NEW & NOTEWORTHY ANG II-induced histone deacetylase 5 (HDAC5) phosphorylation and nuclear export occurs via the phosphoinositide 3-kinase/Akt pathway. Akt, through HDAC5, regulates ANG II-induced expression of early growth response protein-1 (Egr-1), which is a transcription factor linked with vascular dysfunction. Inhibition of HDAC5 exclusion by nuclear export inhibitors suppresses ANG II-induced Egr-1 expression. HDAC5 is an upstream mediator of Egr-1 expression and cell hypertrophy in response to ANG II in vascular smooth muscle cells.
['Truong|Vanessa|V|', 'Jain|Ashish|A|', 'Anand-Srivastava|Madhu B|MB|', 'Srivastava|Ashok K|AK|']
D021581:Active Transport, Cell Nucleus D000804:Angiotensin II D000818:Animals D002460:Cell Line D051766:Early Growth Response Protein 1 D056572:Histone Deacetylase Inhibitors D006655:Histone Deacetylases D006984:Hypertrophy D008297:Male D009131:Muscle, Smooth, Vascular D032389:Myocytes, Smooth Muscle D019869:Phosphatidylinositol 3-Kinases D000081082:Phosphoinositide-3 Kinase Inhibitors D010766:Phosphorylation D047428:Protein Kinase Inhibitors D051057:Proto-Oncogene Proteins c-akt D051381:Rats D017207:Rats, Sprague-Dawley D015398:Signal Transduction D066253:Vascular Remodeling
histone deacetylase 5 Egr-1 vascular smooth muscle cells angiotensin II PI3K/Akt