Synthetic retinoid Am80 inhibits interaction of KLF5 with RARα through inducing KLF5 dephosphorylation mediated by the PI3K/Akt signaling in vascular smooth muscle cells

Abstract 

Krüppel-like factor 5 (KLF5) is known to physically interact with retinoic acid receptor-α (RARα). Here, we show that Am80 inhibited the interaction between KLF5 and RARα and this inhibitory effect was accompanied by the dephosphorylation of KLF5 in VSMCs. Treating VSMCs with LY294002, the PI3K/Akt inhibitor, abrogated Am80-induced KLF5 dephosphorylation and reversed Am80-induced suppression of interaction between KLF5 and RARα, whereas treating vascular smooth muscle cells (VSMCs) with SB203580, the p38 kinase inhibitor, attenuated the interaction between KLF5 and RARα. Constitutively active p38 kinase MKK6b infection prevented the KLF5 dephosphorylation induced by Am80. In conclusion, Am80 induces KLF5 dephosphorylation by activating PI3K/Akt signaling, and inhibits KLF5 phosphorylation by blocking p38 signaling, subsequently leading to the suppression of interaction of KLF5 with RARα.

Structured summary

MINT-7013243: Klf5 (uniprotkb:Q66HP1) physically interacts (MI:0218) with RAR alpha (uniprotkb:Q9QWJ1) by anti bait coimmunoprecipitation (MI:0006)

Abbreviations: ATRA, all-trans retinoic acid, DMSO, dimethyl sulfoxide, FBS, fetal bovine serum, iNOS, inducible NO synthase, KLF5, Krüppel-like factor 5, MAPK, mitogen-activated protein kinase, PAI-1, plasminogen activator inhibitor-1, PI3K, phosphoinositide 3-kinase, RARα, retinoic acid receptor-α, VEGF, vascular endothelial growth factor, VSMCs, vascular smooth muscle cells

Keywords: Krüppel-like factor 5, Retinoic acid receptor-α, Retinoid, PI3K/Akt, p38 mitogen-activated protein kinase, Vascular smooth muscle cell