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T-type Ca²⁺ channels regulate the exit of cardiac myocytes from the cell cycle after birth

Fang Wang1, Hui Gao, Hajime Kubo

  • 1Cardiovascular Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140, USA.

Journal of Molecular and Cellular Cardiology
|June 8, 2013
PubMed

Insights

T-type calcium channels (TTCCs) regulate cardiac myocyte maturation. Their absence slows cell cycle exit and results in smaller adult heart cells, impacting heart development.

Area of Science:

  • Cardiovascular Biology
  • Cellular Physiology
  • Developmental Biology

Background:

  • T-type calcium channels (TTCCs) are present in the fetal heart but diminish in ventricular myocytes postnatally.
  • The α1G subunit is a key component of TTCCs involved in cardiac development.

Purpose of the Study:

  • To investigate the role of α1G TTCCs in myocyte maturation and cell cycle withdrawal after birth.
  • To understand the influence of TTCCs on cardiac myocyte size and proliferation.

Main Methods:

  • Cardiac myocytes were isolated from neonatal and adult wild type, α1G knockout, and α1G overexpressing mice.
  • Measurements included Bromodeoxyuridine (BrdU) uptake, myocyte nucleation, cell cycle analysis, and T-type calcium currents.

Main Results:

  • Loss of functional TTCCs in α1G knockout myocytes correlated with reduced bi-nucleation and slower cell cycle exit.
  • Neonatal α1G knockout myocytes were smaller and exhibited delayed bi-nucleation compared to wild type.
  • Adult α1G knockout hearts had smaller myocytes, while α1G overexpressing myocytes were larger.

Conclusions:

  • Functional TTCCs are crucial for normal myocyte bi-nucleation and cell cycle exit post-birth.
  • α1G TTCCs play a significant role in regulating myocyte size and the transition from proliferation to quiescence.
  • Disruption of TTCCs leads to altered cardiac myocyte development and smaller adult heart cells.
Abstract

Keywords:
Cardiac myocytesCell cycleT-type Ca(2+) channels

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