Depletion of Tip60 from In Vivo Cardiomyocytes Increases Myocyte Density, Followed by Cardiac Dysfunction, Myocyte Fallout and Lethality. PLoS One 2016;11(10):e0164855
Date
10/22/2016Pubmed ID
27768769Pubmed Central ID
PMC5074524DOI
10.1371/journal.pone.0164855Scopus ID
2-s2.0-84992386888 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
Tat-interactive protein 60 (Tip60), encoded by the Kat5 gene, is a member of the MYST family of acetyltransferases. Cancer biology studies have shown that Tip60 induces the DNA damage response, apoptosis, and cell-cycle inhibition. Although Tip60 is expressed in the myocardium, its role in cardiomyocytes (CMs) is unclear. Earlier studies here showed that application of cardiac stress to globally targeted Kat5+/-haploinsufficient mice resulted in inhibition of apoptosis and activation of the CM cell-cycle, despite only modest reduction of Tip60 protein levels. It was therefore of interest to ascertain the effects of specifically and substantially depleting Tip60 from CMs using Kat5LoxP/-;Myh6-Cre mice in the absence of stress. We report initial findings using this model, in which the effects of specifically depleting Tip60 protein from ventricular CMs, beginning at early neonatal stages, were assessed in 2-12 week-old mice. Although 5'-bromodeoxyuridine immunostaining indicated that CM proliferation was not altered at any of these stages, CM density was increased in 2 week-old ventricles, which persisted in 4 week-old hearts when TUNEL staining revealed inhibition of apoptosis. By week 4, levels of connexin-43 were depleted, and its patterning was dysmorphic, concomitant with an increase in cardiac hypertrophy marker expression and interstitial fibrosis. This was followed by systolic dysfunction at 8 weeks, after which extensive apoptosis and CM fallout occurred, followed by lethality as mice approached 12 weeks of age. In summary, chronic depletion of Tip60 from the ventricular myocardium beginning at early stages of neonatal heart development causes CM death after 8 weeks; hence, Tip60 protein has a crucial function in the heart.
Author List
Fisher JB, Horst A, Wan T, Kim MS, Auchampach J, Lough JAuthors
John A. Auchampach PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinTina C. Wan PhD Research Scientist II in the Pediatrics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AllelesAnimals
Heart
Histone Acetyltransferases
Lysine Acetyltransferase 5
Mice
Mice, Transgenic
Myocytes, Cardiac
Trans-Activators
