PMID- 28878120 OWN - NLM STAT- MEDLINE DCOM- 20190813 LR - 20220113 IS - 2379-3708 (Electronic) IS - 2379-3708 (Linking) VI - 2 IP - 17 DP - 2017 Sep 7 TI - Mdm2 regulates cardiac contractility by inhibiting GRK2-mediated desensitization of beta-adrenergic receptor signaling. LID - 95998 [pii] LID - 10.1172/jci.insight.95998 [doi] LID - e95998 AB - The oncoprotein Mdm2 is a RING domain-containing E3 ubiquitin ligase that ubiquitinates G protein-coupled receptor kinase 2 (GRK2) and beta-arrestin2, thereby regulating beta-adrenergic receptor (betaAR) signaling and endocytosis. Previous studies showed that cardiac Mdm2 expression is critical for controlling p53-dependent apoptosis during early embryonic development, but the role of Mdm2 in the developed adult heart is unknown. We aimed to identify if Mdm2 affects betaAR signaling and cardiac function in adult mice. Using Mdm2/p53-KO mice, which survive for 9-12 months, we identified a critical and potentially novel role for Mdm2 in the adult mouse heart through its regulation of cardiac beta1AR signaling. While baseline cardiac function was mostly similar in both Mdm2/p53-KO and wild-type (WT) mice, isoproterenol-induced cardiac contractility in Mdm2/p53-KO was significantly blunted compared with WT mice. Isoproterenol increased cAMP in left ventricles of WT but not of Mdm2/p53-KO mice. Additionally, while basal and forskolin-induced calcium handling in isolated Mdm2/p53-KO and WT cardiomyocytes were equivalent, isoproterenol-induced calcium handling in Mdm2/p53-KO was impaired. Mdm2/p53-KO hearts expressed 2-fold more GRK2 than WT. GRK2 polyubiquitination via lysine-48 linkages was significantly reduced in Mdm2/p53-KO hearts. Tamoxifen-inducible cardiomyocyte-specific deletion of Mdm2 in adult mice also led to a significant increase in GRK2, and resulted in severely impaired cardiac function, high mortality, and no detectable betaAR responsiveness. Gene delivery of either Mdm2 or GRK2-CT in vivo using adeno-associated virus 9 (AAV9) effectively rescued beta1AR-induced cardiac contractility in Mdm2/p53-KO. These findings reveal a critical p53-independent physiological role of Mdm2 in adult hearts, namely, regulation of GRK2-mediated desensitization of betaAR signaling. FAU - Jean-Charles, Pierre-Yves AU - Jean-Charles PY AD - Department of Medicine, Division of Cardiology, and. FAU - Yu, Samuel Mon-Wei AU - Yu SM AD - Department of Medicine, Division of Cardiology, and. FAU - Abraham, Dennis AU - Abraham D AD - Department of Medicine, Division of Cardiology, and. FAU - Kommaddi, Reddy Peera AU - Kommaddi RP AD - Department of Medicine, Division of Cardiology, and. FAU - Mao, Lan AU - Mao L AD - Department of Medicine, Division of Cardiology, and. FAU - Strachan, Ryan T AU - Strachan RT AD - Department of Medicine, Division of Cardiology, and. FAU - Zhang, Zhu-Shan AU - Zhang ZS AD - Department of Medicine, Division of Cardiology, and. FAU - Bowles, Dawn E AU - Bowles DE AD - Department of Surgery, Duke University Medical Center, Durham, North Carolina, USA. FAU - Brian, Leigh AU - Brian L AD - Department of Medicine, Division of Cardiology, and. FAU - Stiber, Jonathan A AU - Stiber JA AD - Department of Medicine, Division of Cardiology, and. FAU - Jones, Stephen N AU - Jones SN AD - Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA. FAU - Koch, Walter J AU - Koch WJ AD - Center for Translational Medicine, Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA. FAU - Rockman, Howard A AU - Rockman HA AD - Department of Medicine, Division of Cardiology, and. AD - Department of Cell Biology, and. AD - Department of Molecular Genetics, Duke University Medical Center, Durham, North Carolina, USA. FAU - Shenoy, Sudha K AU - Shenoy SK AD - Department of Medicine, Division of Cardiology, and. AD - Department of Cell Biology, and. LA - eng GR - R01 HL118369/HL/NHLBI NIH HHS/United States GR - K08 HL125905/HL/NHLBI NIH HHS/United States GR - R01 CA077735/CA/NCI NIH HHS/United States GR - P30 DK096493/DK/NIDDK NIH HHS/United States GR - R01 HL080525/HL/NHLBI NIH HHS/United States GR - P01 HL075443/HL/NHLBI NIH HHS/United States GR - R01 HL061690/HL/NHLBI NIH HHS/United States GR - R01 HL056687/HL/NHLBI NIH HHS/United States GR - R37 HL061690/HL/NHLBI NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't DEP - 20170907 PL - United States TA - JCI Insight JT - JCI insight JID - 101676073 RN - 0 (Adrenergic beta-Agonists) RN - 0 (Receptors, Adrenergic, beta) RN - 0 (Trp53 protein, mouse) RN - 0 (Tumor Suppressor Protein p53) RN - EC 2.3.2.27 (Mdm2 protein, mouse) RN - EC 2.3.2.27 (Proto-Oncogene Proteins c-mdm2) RN - EC 2.7.11.15 (GRK2 protein, mouse) RN - EC 2.7.11.16 (G-Protein-Coupled Receptor Kinase 2) RN - L628TT009W (Isoproterenol) MH - Adrenergic beta-Agonists/pharmacology MH - Animals MH - Echocardiography MH - G-Protein-Coupled Receptor Kinase 2/antagonists & inhibitors/*metabolism MH - Heart/diagnostic imaging/physiology MH - Hemodynamics/drug effects MH - Isoproterenol/pharmacology MH - Mice MH - Mice, Knockout MH - Myocardial Contraction/*physiology MH - Myocytes, Cardiac/enzymology/metabolism MH - Phosphorylation MH - Proto-Oncogene Proteins c-mdm2/genetics/*physiology MH - Receptors, Adrenergic, beta/*metabolism MH - *Signal Transduction MH - Tumor Suppressor Protein p53/genetics/metabolism MH - Ubiquitination PMC - PMC5621915 OTO - NOTNLM OT - Cardiology OT - Heart failure OT - Oncology OT - Ubiquitin-proteosome system COIS- Conflict of interest: The authors have declared that no conflict of interest exists. EDAT- 2017/09/08 06:00 MHDA- 2019/08/14 06:00 PMCR- 2017/09/07 CRDT- 2017/09/08 06:00 PHST- 2017/06/27 00:00 [received] PHST- 2017/07/27 00:00 [accepted] PHST- 2017/09/08 06:00 [pubmed] PHST- 2019/08/14 06:00 [medline] PHST- 2017/09/08 06:00 [entrez] PHST- 2017/09/07 00:00 [pmc-release] AID - 95998 [pii] AID - 10.1172/jci.insight.95998 [doi] PST - epublish SO - JCI Insight. 2017 Sep 7;2(17):e95998. doi: 10.1172/jci.insight.95998. eCollection 2017 Sep 7.