GRP78 (Glucose-Regulated Protein of 78 kDa) Promotes Cardiomyocyte Growth Through Activation of GATA4 (GATA-Binding Protein 4)

Guangyu Zhang, Xiaoding Wang, Xukun Bi, Chao Li, Yingfeng Deng, Ali A. Al-Hashimi, Xiang Luo, Thomas G. Gillette, Richard C. Austin, Yanggan Wang, Zhao V. Wang

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The heart manifests hypertrophic growth in response to elevation of afterload pressure. Cardiac myocyte growth involves new protein synthesis and membrane expansion, of which a number of cellular quality control machineries are stimulated to maintain function and homeostasis. The unfolded protein response is potently induced during cardiac hypertrophy to enhance protein-folding capacity and eliminate terminally misfolded proteins. However, whether the unfolded protein response directly regulates cardiac myocyte growth remains to be fully determined. Here, we show that GRP78 (glucose-regulated protein of 78 kDa) - an endoplasmic reticulum-resident chaperone and a critical unfolded protein response regulator - is induced by cardiac hypertrophy. Importantly, overexpression of GRP78 in cardiomyocytes is sufficient to potentiate hypertrophic stimulus-triggered growth. At the in vivo level, TG (transgenic) hearts overexpressing GRP78 mount elevated hypertrophic growth in response to pressure overload. We went further to show that GRP78 increases GATA4 (GATA-binding protein 4) level, which may stimulate Anf (atrial natriuretic factor) expression and promote cardiac hypertrophic growth. Silencing of GATA4 in cultured neonatal rat ventricular myocytes significantly diminishes GRP78-mediated growth response. Our results, therefore, reveal that protein-folding chaperone GRP78 may directly enhance cardiomyocyte growth by stimulating cardiac-specific transcriptional factor GATA4.

Original languageEnglish (US)
Pages (from-to)390-398
Number of pages9
JournalHypertension
Volume73
Issue number2
DOIs
StatePublished - Jan 1 2019

Keywords

  • animals
  • cardiomegaly
  • glucose
  • hypertension
  • rats

ASJC Scopus subject areas

  • Internal Medicine

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