Curcumin suppressed cardiac hypertrophy by inhibiting not only HAT activity but also scaffold function of p300 in cultured cardiomyocytes

Curcumin suppressed cardiac hypertrophy by inhibiting not only HAT activity but also scaffold function of p300 in cultured cardiomyocytes

Yoichi Sunagawa1,2,3, Taishi Terada1, Yukihiro Ishibashi1, Teruhisa Kawamura3, Tomohide Takaya2, Hiromichi Wada3, Yasufumi Katanasaka1, Masashi Komeda4, Toru Kita5, Akira Shimatsu3, Masatoshi Fujita2, Koji Hasegawa3, Tatsuya Morimoto1.

  1. School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
  2. Graduate School of Medicine, Kyoto University, Kyoto, Japan.
  3. Kyoto Medical Center, National Hospital Organization, Kyoto, Japan.
  4. Department of Cardiovascular Surgery, Nagoya Heart Center, Aichi, Japan.
  5. Kobe City Medical Center General Hospital, Hyogo, Japan.

The 6th China-Japan Cardiovascular Forum (Beijing, China), 2010/10/16 (Poster).

Abstract

Purpose: Signals activated by increased hemodynamic overload to the heart finally reach nuclei of cardiac myocytes, change patterns of gene expression and cause their maladaptive hypertrophy. Nuclear acetylation controlled by histone deacetylases and an intrinsic histone acetyltransferase (HAT), p300, is a critical event during this process. Recently we found that a natural compound curcumin inhibited hypertrophic response in cultured cardiomyocytes and prevented the deterioration of systolic function in two different heart failure models in vivo: one model was hypertensive heart disease in salt-sensitive Dahl rats, and the other model was myocardial infarction in rats. However, the precise mechanism of curcumin to inhibit p300 function is still unclear. The goal of this study was to clarify how curcumin repress the p300 function in cardiomyocytes.

Methods: 1) Primary cardiac myocytes from neonatal rats were transfected with pANF-luc, pbMHC-luc, or p300 expression vector and incubated with curcumin (10 mM) or DMSO for 48 h. 2) Cardiac myocytes were stimulated with saline or 30 mM of PE, in the presence of curcumin or DMSO for 48 h. Protein extracts from these cells were transfected with p300 expression vector, or HAT mutant p300 wich loses its HAT activity but retains the ability to interact with transcription factors, and incubated with an HDAC inhibitor, TSA, curcumin or DMSO for 48 h. These cells were subjected to immunocytochemistry and surface area was measured.

Results: 1) Treatment with curcumin significantly inhibited the p300-induced increase in cell size and activities of the ANF and b-MHC promoters. 2) Curcumin repressed the PE-induced increase in both acetylated form of GATA4 and the binding of GATA4 with p300. 3) Treatment with TSA and transfection of an expression vector encoding HAT mutant p300 induced significant increase in cell size. However, the increased by TSA or HAT mutant p300 was smaller than that caused by intact p300. Curcumin inhibited both TSA- and HAT mutant p300-induced hypertrophy as well as intact p300-induced hypertrophy.

Conclusions: Curcumin can inhibit both HAT activity and scaffold function of p300 in cultured cardiomyocytes.