title: Progesterone modulates SERCA2a expression and function in rabbit cardiomyocytes.
abstract: We recently showed that progesterone treatment abolished arrhythmias and sudden cardiac death in a transgenic rabbit model of long QT syndrome type 2 (LQT2). Moreover, levels of cardiac sarco(endo)plasmic reticulum Ca(2+)-ATPase type 2a (SERCA2a) were upregulated in LQT2 heart extracts. We hypothesized that progesterone treatment upregulated SERCA2a expression, thereby reducing Ca(2+)-dependent arrhythmias in LQT2 rabbits. We therefore investigated the effect of progesterone on SERCA2a regulation in isolated cardiomyocytes. Cardiomyocytes from neonatal (3- to 5-day-old) rabbits were isolated, cultured, and treated with progesterone and other pharmacological agents. Immunoblotting was performed on total cell lysates and sarcoplasmic reticulum-enriched membrane fractions for protein abundance, and mRNA transcripts were quantified using real-time PCR. The effect of progesterone on baseline Ca(2+) transients and Ca(2+) clearance was determined using digital imaging. Progesterone treatment increased the total pool of SERCA2a protein by slowing its degradation. Using various pharmacological inhibitors of degradation pathways, we showed that progesterone-associated degradation of SERCA2a involves ubiquitination, and progesterone significantly decreases the levels of ubiquitin-tagged SERCA2a polypeptides. Our digital imaging data revealed that progesterone significantly shortened the decay and duration of Ca(2+) transients. Progesterone treatment increases protein levels and activity of SERCA2a. Progesterone stabilizes SERCA2a, in part, by decreasing the ubiquitination level of SERCA2a polypeptides.
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Karni S
authors.initials: KS
authors.lastname: Moshal
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Karim
authors.initials: K
authors.lastname: Roder
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Tae Yun
authors.initials: TY
authors.lastname: Kim
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Leroy
authors.initials: L
authors.lastname: Cooper
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Patedakis Litvinov
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Yichun
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Vishal
authors.initials: V
authors.lastname: Reddy
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Terentyev
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island.
authors.forename: Bum-Rak
authors.initials: BR
authors.lastname: Choi
authors.affiliation: Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, Rhode Island gideon_koren@brown.edu.
authors.forename: Gideon
authors.initials: G
authors.lastname: Koren
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology*; D011374:Progesterone / Q000494:pharmacology*; D059748:Proteolysis / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination / Q000187:drug effects
chemical_list: D012333:RNA, Messenger; D011374:Progesterone; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases
keywords: SERCA2a; cardiomyocytes; hormones; long QT syndrome; neonate