title: CITED4 induces physiologic hypertrophy and promotes functional recovery after ischemic injury.
abstract: The mechanisms by which exercise mediates its multiple cardiac benefits are only partly understood. Prior comprehensive analyses of the cardiac transcriptional components and microRNAs dynamically regulated by exercise suggest that the CBP/p300-interacting protein CITED4 is a downstream effector in both networks. While CITED4 has documented functional consequences in neonatal cardiomyocytes in vitro, nothing is known about its effects in the adult heart. To investigate the impact of cardiac CITED4 expression in adult animals, we generated transgenic mice with regulated, cardiomyocyte-specific CITED4 expression. Cardiac CITED4 expression in adult mice was sufficient to induce an increase in heart weight and cardiomyocyte size with normal systolic function, similar to the effects of endurance exercise training. After ischemia-reperfusion, CITED4 expression did not change initial infarct size but mediated substantial functional recovery while reducing ventricular dilation and fibrosis. Forced cardiac expression of CITED4 also induced robust activation of the mTORC1 pathway after ischemic injury. Moreover, pharmacological inhibition of mTORC1 abrogated CITED4's effects in vitro and in vivo. Together, these data establish CITED4 as a regulator of mTOR signaling that is sufficient to induce physiologic hypertrophy at baseline and mitigate adverse ventricular remodeling after ischemic injury.
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Vassilios J
authors.initials: VJ
authors.lastname: Bezzerides
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Colin
authors.initials: C
authors.lastname: Platt
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Carolin
authors.initials: C
authors.lastname: Lerchenmüller
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Kaavya
authors.initials: K
authors.lastname: Paruchuri
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Nul Loren
authors.initials: NL
authors.lastname: Oh
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Xiao
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Yunshan
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Mann
authors.affiliation: Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Spiegelman
authors.affiliation: Cardiovascular Division of the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Rosenzweig