Alpha-Catenins Control Cardiomyocyte Proliferation by Regulating Yap Activity

Abstract

Rationale Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. Thus, they are unable to effectively replace dying cells in the injured heart. The recent discovery that the transcriptional co-activator Yap is necessary and sufficient for cardiomyocyte proliferation has gained considerable attention. However, the upstream regulators and signaling pathways that control Yap activity in the heart are poorly understood. Objective To investigate the role of α-catenins in the heart using cardiac-specific αE- and αT-catenin double knockout (α-cat DKO) mice. Methods and Results We used two cardiac-specific Cre transgenes to delete both αE-catenin (Ctnna1) and αT-catenin (Ctnna3) genes either in the perinatal or in the adult heart. Perinatal depletion of α-catenins increased cardiomyocyte number in the postnatal heart. Increased nuclear Yap and the cell cycle regulator cyclin D1 accompanied cardiomyocyte proliferation in the α-cat DKO hearts. Fetal genes were increased in the α-cat DKO hearts indicating a less mature cardiac gene expression profile. Knockdown (KD) of α-catenins in neonatal rat cardiomyocytes also resulted in increased proliferation, which could be blocked by KD of Yap. Finally, inactivation of α-catenins in the adult heart using an inducible Cre led to increased nuclear Yap and cardiomyocyte proliferation and improved contractility following myocardial infarction. Conclusions These studies demonstrate that α-catenins are critical regulators of Yap, a transcriptional co-activator essential for cardiomyocyte proliferation. Furthermore, we provide proof-of-concept that inhibiting α-catenins might be a useful strategy to promote myocardial regeneration following injury.

The SR/ER-mitochondria calcium crosstalk is regulated by GSK3β during reperfusion injury

“…Ventricular cardiomyocytes were isolated using enzymatic digestion according to previously described procedure. 35,36 Briefly, WT mice were anesthetized with pentobarbital (70 mg/kg) (Sanofi Santé Animale, Libourne, France) and the heart was quickly harvested and retrogradely perfused at 37°C for 6-8 min with a perfusion buffer (113 mM NaCl, 4.7 mM KCl, 0.6 mM KH 2 PO 4 , 0.6 mM Na 2 HPO 4 , 1.2 mM MgSO 4 , 12 mM NaHCO 3 , 10 mM KHCO 3 , 10 mM HEPES, 30 mM Taurine, pH 7.4) containing 10 mM 2,3-butanedione, 5.5 mM glucose, 12.5 μM CaCl 2 , 0.1 mg/ml of liberase (Roche) and 0.14 mg/ml trypsin (Sigma). Isolated myocytes were then maintained in culture in laminin-(10 μg/ml) precoated dishes with M199 medium (Invitrogen) and allowed to attach for 2 h before analysis.…”

The cardiac protein αT-catenin contributes to chemical-induced asthma

“…␣T-cat KO C57BL/6 mice were obtained from Dr. Glenn Radice (Thomas Jefferson University, Philadelphia, PA), which were bred with C57BL/6 wild-type (WT) mice to create heterozygote, C57BL/6 breeders. WT and ␣T-cat KO mice used for experimentation were littermates or descendants from littermates and were genotyped similarly as shown previously (14). ␣T-cat-null specific primers, which generate separate bands in KO and WT mice, were used to genotype by using PCR: forward 5=-TCTATTTTTGAGGCTGTCG-3=; reverse 5=-CAAACTTATGCGTGGTG-3=.…”

Regulation of Myocardial Cell Growth and Death by the Hippo Pathway

“…65-68 Agonists for G protein-coupled receptors also regulate Yap through similar mechanisms. 69 In addition, it has recently been shown α-catenin negatively regulates Yap, 70 while S1P positively regulates Yap in CMs. 4 Figure 2.…”