In:
Journal of Cellular Physiology, Wiley, Vol. 231, No. 2 ( 2016-02), p. 393-402
Kurzfassung:
Glycogen synthase kinase (GSK)‐3β, a serine/threonine kinase with an inhibitory role in glycogen synthesis in hepatocytes and skeletal muscle, is also expressed in cardiac and smooth muscles. Inhibition of GSK‐3β results in cardiac hypertrophy through reducing phosphorylation and increasing transcriptional activity of myocardin, a transcriptional co‐activator for serum response factor. Myocardin plays critical roles in differentiation of smooth muscle cells (SMCs). This study, therefore, aimed to examine whether and how inhibition of GSK‐3β regulates myocardin activity in human vascular SMCs. Treatment of SMCs with the GSK‐3β inhibitors AR‐A014418 and TWS 119 significantly reduced endogenous myocardin activity, as indicated by lower expression of myocardin target genes (and gene products), CNN1 (calponin), TAGLN1 (SM22), and ACTA2 (SM α‐actin). In human SMCs overexpressing myocardin through the T‐REx system, treatment with either GSK‐3β inhibitor also inhibited the expression of CNN1, TAGLN1, and ACTA2. These effects of GSK‐3β inhibitors were mimicked by transfection with GSK‐3β siRNA. Notably, both AR‐A014418 and TWS 119 decreased the serine/threonine phosphorylation of myocardin. The chromatin immunoprecipitation assay showed that AR‐A014418 treatment reduced myocardin occupancy of the promoter of the myocardin target gene ACTA2. Overexpression of a dominant‐negative GSK‐3β mutant in myocardin‐overexpressing SMCs reduced the expression of calponin, SM22, and SM α‐actin. As expected, overexpression of constitutively active or wild‐type GSK‐3β in SMCs without myocardin overexpression increased expression of these proteins. In summary, our results indicate that inhibition of GSK‐3β reduces myocardin transcriptional activity, suggesting a role for GSK‐3β in myocardin transcriptional activity and smooth muscle differentiation. J. Cell. Physiol. 231: 393–402, 2016. © 2015 Wiley Periodicals, Inc.
Materialart:
Online-Ressource
ISSN:
0021-9541
,
1097-4652
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2016
ZDB Id:
1478143-8
SSG:
12
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