Abstract 14914: Inactivation of Neddylation Activating Enzyme 1 (NAE1) in Mice and Rats Leads to Cardiac Developmental and Functional Defects
Exploring the molecular mechanisms that govern cardiac development is important for understanding congenital heart disease and for developing strategies for cardiac regeneration. Neddylation is a protein posttranslational modification that covalently conjugates a ubiquitin-like protein NEDD8 to target proteins. Neddylation requires NEDD8 specific E1(a heterodimer consisting of NAE1 and UBA3), E2 (UBC12) and E3 ligases, and is purported to control a variety of cellular processes through modulating the function of its targets, yet its biological functions in vertebrates are largely unknown. Here we report the discovery of an indispensable role of neddylation in cardiac growth, chamber maturation, and embryonic and perinatal survival. NAE1 is expressed as early as E12.5 in mouse hearts. Neddylation is activated in fetal and neonatal hearts but downregulated in adult hearts. Germline knockout of NAE1 in mice led to embryonic lethality before E10.5, revealing its critical role in embryonic development. Mice with cardiomyocyte-restricted knockout of NAE1 (αMHC-CreTg/+::NAE1flox/flox) exhibited myocardial hypoplasia, defective ventricular chamber maturation, heart failure, and embryonic and neonatal lethality. Cardiac hypoplasia was caused by drastically reduced cardiomyocyte proliferation, which was attributable to dysregulated expression of multiple cell cycle genes. Furthermore, transient inhibition of NAE1 with a specific inhibitor MLN4924 in neonatal rats caused a decrease in cardiomyocyte proliferation, which eventually led to ventricular chamber dilation and cardiac dysfunction in adulthood. In vitro, both MLN4924 treatment and silencing of UBC12 resulted in proliferation arrest in isolated cardiomyocytes, indicating a cell autonomous role of neddylation in cardiomyocyte proliferation. Mechanistically, MLN4924 or NAE1 deficiency abolished neddylation of cullin proteins, a major component of cullin-RING ubiquitin ligases (CRLs), and accumulated a panel of negative cell cycle regulators presumably as a consequence of loss of CRLs activities. Taken together, these data identify a heretofore undescribed function of neddylation that regulates cardiomyocyte proliferation in the embryonic and neonatal heart.
Author Disclosures: J. Zou: None. J. Li: None. W. Ma: None. G. Yue: None. A. Zhang: None. G. Hu: None. J. Zhou: None. H. Su: None.
- © 2016 by American Heart Association, Inc.