title: Cardiac myocyte follistatin-like 1 functions to attenuate hypertrophy following pressure overload.
abstract: Factors secreted by the heart, referred to as "cardiokines," have diverse actions in the maintenance of cardiac homeostasis and remodeling. Follistatin-like 1 (Fstl1) is a secreted glycoprotein expressed in the adult heart and is induced in response to injurious conditions that promote myocardial hypertrophy and heart failure. The aim of this study was to investigate the role of cardiac Fstl1 in the remodeling response to pressure overload. Cardiac myocyte-specific Fstl1-KO mice were constructed and subjected to pressure overload induced by transverse aortic constriction (TAC). Although Fstl1-KO mice displayed no detectable baseline phenotype, TAC led to enhanced cardiac hypertrophic growth and a pronounced loss in ventricular performance by 4 wk compared with control mice. Conversely, mice that acutely or chronically overexpressed Fstl1 were resistant to pressure overload-induced hypertrophy and cardiac failure. Fstl1-deficient mice displayed a reduction in TAC-induced AMP-activated protein kinase (AMPK) activation in heart, whereas Fstl1 overexpression led to increased myocardial AMPK activation under these conditions. In cultured neonatal cardiomyocytes, administration of Fstl1 promoted AMPK activation and antagonized phenylephrine-induced hypertrophy. Inhibition of AMPK attenuated the antihypertrophic effect of Fstl1 treatment. These results document that cardiac Fstl1 functions as an autocrine/paracrine regulatory factor that antagonizes myocyte hypertrophic growth and the loss of ventricular performance in response to pressure overload, possibly through a mechanism involving the activation of the AMPK signaling axis.
authors: Whitaker Cardiovascular Institute, Boston University, Boston, MA 02118, USA.
authors: Masayuki
authors: M
authors: Shimano
authors: Noriyuki
authors: N
authors: Ouchi
authors: Kazuto
authors: K
authors: Nakamura
authors: Bram
authors: B
authors: van Wijk
authors: Koji
authors: K
authors: Ohashi
authors: Yasuhide
authors: Y
authors: Asaumi
authors: Akiko
authors: A
authors: Higuchi
authors: David R
authors: DR
authors: Pimentel
authors: Flora
authors: F
authors: Sam
authors: Toyoaki
authors: T
authors: Murohara
authors: Maurice J B
authors: MJ
authors: van den Hoff
authors: Kenneth
authors: K
authors: Walsh
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015153:Blotting, Western; D006332:Cardiomegaly / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004452:Echocardiography; D038702:Follistatin-Related Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011312:Pressure; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D018709:Statistics, Nonparametric; D020257:Ventricular Remodeling / Q000235:genetics / Q000502:physiology*
chemical_list: D017931:DNA Primers; D038702:Follistatin-Related Proteins; C448720:Fstl1 protein, mouse