Disturbed flow-activated p90RSK kinase accelerates atherosclerosis by inhibiting SENP2 function
Kyung-Sun Heo, … , Keigi Fujiwara, Jun-ichi Abe
Kyung-Sun Heo, … , Keigi Fujiwara, Jun-ichi Abe
Published February 17, 2015
Citation Information: J Clin Invest. 2015;125(3):1299-1310. https://doi.org/10.1172/JCI76453.
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Research Article Vascular biology

Disturbed flow-activated p90RSK kinase accelerates atherosclerosis by inhibiting SENP2 function

Abstract

Disturbed blood flow (d-flow) causes endothelial cell (EC) dysfunction, leading to atherosclerotic plaque formation. We have previously shown that d-flow increases SUMOylation of p53 and ERK5 through downregulation of sentrin/SUMO-specific protease 2 (SENP2) function; however, it is not known how SENP2 itself is regulated by d-flow. Here, we determined that d-flow activated the serine/threonine kinase p90RSK, which subsequently phosphorylated threonine 368 (T368) of SENP2. T368 phosphorylation promoted nuclear export of SENP2, leading to downregulation of eNOS expression and upregulation of proinflammatory adhesion molecule expression and apoptosis. In an LDLR-deficient murine model of atherosclerosis, EC-specific overexpression of p90RSK increased EC dysfunction and lipid accumulation in the aorta compared with control animals; however, these pathologic changes were not observed in atherosclerotic mice overexpressing dominant negative p90RSK (DN-p90RSK). Moreover, depletion of SENP2 in these mice abolished the protective effect of DN-p90RSK overexpression. We propose that p90RSK-mediated SENP2-T368 phosphorylation is a master switch in d-flow–induced signaling, leading to EC dysfunction and atherosclerosis.

Authors

Kyung-Sun Heo, Nhat-Tu Le, Hannah J. Cushman, Carolyn J. Giancursio, Eugene Chang, Chang-Hoon Woo, Mark A. Sullivan, Jack Taunton, Edward T.H. Yeh, Keigi Fujiwara, Jun-ichi Abe

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Figure 3

p90RSK-mediated SENP2-T368 phosphorylation is critical for p53 SUMOylation.

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p90RSK-mediated SENP2-T368 phosphorylation is critical for p53 SUMOylati...
(A) An LC-MS/MS analysis identified SENP2 phosphorylation sites by p90RSK at T35, S38, and T368 with a less than 0.05 error (upper panel). An LC-MS/MS plot of different peptide fragments shows T368 phosphorylation based on mass shift of phosphorylated threonine within H2O (686 Da, lower panel). (B and C) CHO cells were cotransfected with 4 plasmids, Flag-p53, HA-SUMO3, Xpress-p90RSK1, and an additional plasmid containing one of the following pCS-Myc–tagged plasmids encoding SENP2-WT, SENP2-T35A, SENP2-S38A, or SENP2-T368A. Control plasmid contained only Flag-p53 and HA-SUMO. p53 SUMOylation was determined as described in Methods. p53, SUMO3, p90RSK, and SENP2 expression were detected by Western blotting. (D) HUVECs were transduced with Ad-SENP2-WT or SENP2 phosphorylation mutants as indicated and stimulated by d-flow or no flow (–) for 3 hours, and SENP2-T368 phosphorylation was detected using anti–phospho–SENP2-T368. (B–D) The blots shown are representative of 3 independent experiments. (E) After transduction of Ad-LacZ or Ad-DN-p90RSK, d-flow–induced SENP2-T368 phosphorylation was analyzed by Western blotting. Quantification of data represents mean ± SEM (lower panel, n = 3). **P < 0.01, compared with no-flow conditions in the presence of Ad-LacZ; ##P < 0.01, compared with each time point of Ad-LacZ control by 1-way ANOVA followed by Bonferroni’s post hoc test.