Neddylation is Required for Ventricular Chamber Maturation through Sustaining Cardiomyocyte Proliferation and Developmental Metabolic Transition

Abstract

Perturbation of cardiac development can lead to congenital heart diseases that affect approximately 1/100 live births, thus understanding the molecular mechanisms underlying cardiac development is highly important for developing novel therapeutic strategies to these diseases. Neddylation is a post‐translational modification that covalently attaches a small ubiquitin (Ub)‐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 regulating the function of its targets. To date, the importance of neddylation in the heart remains unknown. Here we report an indispensable role of neddylation in cardiac development. Neddylation was specifically inhibited in the mouse heart by αMHCCre‐mediated deletion of NAE1, the essential subunit of NEDD8 E1 enzyme. Temporal histological and functional analyses revealed that mice lacking neddylation displayed cardiac hypoplasia and ventricular non‐compaction at E16.5, which became more pronounced by P1, eventually leading to heart failure and perinatal lethality by P7. Transcriptome analysis identified that the defects in cardiac chamber maturation are attributable to dysregulation of cardiomyocyte proliferation and disruption of developmental metabolic transition. On the one hand, neddylation deficiency abolished neddylation of cullin proteins, a major component of cullin‐RING ubiquitin ligases, and stabilized Hippo kinases Mst1 and LATS2, which in turn phosphorylated and inactivated YAP, a transcription cofactor necessary for cardiomyocyte proliferation, thereby leading to dysregulation of a number of cell cycle‐regulatory genes and blockade of cardiomyocyte proliferation in vivo and in vitro. Moreover, reactivation of YAP signaling by either silencing LATS2 or overexpression of LATS2‐resistant YAP mutant restored cardiomyocyte proliferation in NAE1‐inactivated cardiomyocytes. On the other hand, inhibition of neddylation increased HIF1α, a novel NEDD8 target, and activated HIF1α signaling in the mutant hearts, which resulted in upregulated glycolysis and downregulated fatty acid utilization. Consequently, the developing mutant hearts failed to establish oxidative metabolism that is essential for the formation of a functionally competent postnatal heart. Taken together, our findings demonstrate the importance of neddylation in the developing heart, more specifically, in ventricular chamber maturation, and identify neddylation as a novel regulator of Hippo‐YAP and HIF1α signaling to promote cardiomyocyte proliferation and developmental metabolic maturation, respectively.Support or Funding InformationNIH NHLBI R01: R01HL124248 – (PI: Huabo Su) AHA Postdoctoral Fellowship: 17POST33410592 – (PI: Jianqiu Zou)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.