Highlighted Article SHP2 mediates gp130-dependent cardiomyocyte hypertrophy via negative regulation of skeletal alpha-actin gene Yoshikazu Nakaoka a, ⁎, Wataru Shioyama a , Satoshi Kunimoto b,c , Yoh Arita a , Kaori Higuchi a , Kaori Yamamoto a , Yasushi Fujio d , Keigo Nishida e , Tadashi Kuroda a , Hisao Hirota a,1 , Keiko Yamauchi-Takihara a , Toshio Hirano e,f , Issei Komuro a , Naoki Mochizuki b a Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan b Department of Structural Analysis, National Cardiovascular Center Research Institute, 5-7-1, Fujishirodai, Suita, Osaka, 565-8565, Japan c Department of Medicine, Division of Cardiology, Nihon University School of Medicine, 30-1 Ohyaguchi-kamicho, Itabashi-ku, Tokyo, 173-8610, Japan d Department of Clinical Pharmacology and Pharmacogenomics, Osaka University Graduate School of Pharmaceutical Sciences, 1-6, Yamadaoka, Suita City, Osaka, 565-0871, Japan e Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology (RCAI), 1-7-22, Suehiro-cho, Tsurumi, Yokohama, 230-0045, Japan f Laboratory of Developmental Immunology, Osaka University Graduate School of Frontier Biosciences and Graduate School of Medicine, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan abstract article info Article history: Received 15 October 2009 Received in revised form 27 February 2010 Accepted 2 March 2010 Available online 11 March 2010 Keywords: Cardiac hypertrophy Fetal cardiac gene Skeletal alpha-actin SHP2 Protein tyrosine phosphatase RhoA Cytokine Leukemia inhibitory factor (LIF) Gp130 Elongation Endothelin-1 (ET-1) G protein-coupled receptor (GPCR) Extracellular signal-regulated kinase 5 (ERK5) Morphological and biochemical phenotypes of cardiomyocyte hypertrophy are determined by neurohumoral factors. Stimulation of G protein-coupled receptor (GPCR) results in uniform cell enlargement in all directions with an increase in skeletal α-actin (α-SKA) gene expression, while stimulation of gp130 receptor by interleukin-6 (IL-6)-related cytokines induces longitudinal elongation with no increase in α-SKA gene expression. Thus, α-SKA is a discriminating marker for hypertrophic phenotypes; however, regulatory mechanisms of α-SKA gene expression remain unknown. Here, we clarified the role of SH2-containing protein tyrosine phosphatase 2 (SHP2) in α-SKA gene expression. In neonatal rat cardiomyocytes, endothelin-1 (ET-1), a GPCR agonist, but not leukemia inhibitory factor (LIF), an IL-6-related cytokine, induced RhoA activation and promotes α-SKA gene expression via RhoA. In contrast, LIF, but not ET-1, induced activation of SHP2 in cardiomyocytes, suggesting that SHP2 might negatively regulate α-SKA gene expression downstream of gp130. Therefore, we examined the effect of adenovirus-mediated overexpression of wild-type SHP2 (SHP2 WT ), dominant-negative SHP2 (SHP2 C/S ), or β-galactosidase (β-gal), on α-SKA gene expression. LIF did not upregulate α-SKA mRNA in cardiomyocytes overexpressing either β-gal or SHP2 WT . In cardiomyocytes overexpressing SHP2 C/S , LIF induced upregulation of α-SKA mRNA, which was abrogated by concomitant overexpression of either C3-toxin or dominant-negative RhoA. RhoA was activated after LIF stimulation in the cardiomyocytes overexpressing SHP2 C/S , but not in myocytes overexpressing β-gal. Furthermore, SHP2 mediates LIF-induced longitudinal elongation of cardiomyocytes via ERK5 activation. Collectively, these findings indicate that SHP2 negatively regulates α-SKA expression via RhoA inactivation and suggest that SHP2 implicates ERK5 in cardiomyocyte elongation downstream of gp130. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Cardiac hypertrophy is one of the most important compensatory responses of the myocardium. Cardiac hypertrophy is induced for the maintenance of normal cardiac function in response to pressure overload, in the clinical setting such as hypertension, or volume overload during valvular insufficiency. The former can take place as “concentric hypertrophy” through thickening of the ventricular wall. The latter can occur as “eccentric hypertrophy” by chamber dilatation [1]. Cardiac hyper- trophy accompanies reactivation of fetal cardiac gene program, which is distinctly reactivated in pressure overload vs volume overload [2]. Pressure overload results in the coordinated induction of the fetal cardiac genes such as atrial natriuretic factor (ANF) and skeletal α-actin (α-SKA). However, volume overload hypertrophy is associated with a selective induction of ANF, and no induction of α-SKA [2]. These findings suggest Journal of Molecular and Cellular Cardiology 49 (2010) 157–164 Abbreviations: SHP2, Src homology 2 (SH2)-containing protein tyrosine phospha- tase 2; Gab1, Grb2-associated binder 1; WT, wild-type; RTK, receptor tyrosine kinase; PI3K, phosphatidylinositol 3-kinase; MAPK, mitogen activated protein kinase; ERK1/2, extracellular signal-regulated kinase 1/2; ERK5, extracellular signal-regulated kinase 5; SH2, Src homology 2; LIF, leukemia inhibitory factor; CT-1, casrdiotrophin-1; GPCR, G protein-coupled receptor; ET-1, endothelin-1; PE, phenylephrine; Ang II, angiotensin II; ANF, atrial natriuretic factor; BNP, brain natriuretic polypeptide; α-SKA, skeletal α- actin; GAPDH, glyceraldehydes-3-phosphate dehydrogenase; DMEM, Dulbecco's modified Eagle's medium; FBS, fetal bovine serum; β-gal, β-galactosidase; PBS, phosphate-buffered saline; IP, immunoprecipitation; IB, immunoblotting; PTP, protein tyrosine phosphatase. ⁎ Corresponding author. Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan. Tel.: +81 6 6879 3632; fax: +81 6 6879 3634. E-mail address: ynakaoka@imed3.med.osaka-u.ac.jp (Y. Nakaoka). 1 Deceased on December 27, 2005. 0022-2828/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.yjmcc.2010.03.001 Contents lists available at ScienceDirect Journal of Molecular and Cellular Cardiology journal homepage: www.elsevier.com/locate/yjmcc