Calcium Channel Blockade in Embryonic Cardiac Progenitor Cells Disrupts Normal Cardiac Cell Differentiation

Abstract

We suggest that characterization of processes involved in differentiation of the pluripotential cardiac precursor cells in their embryonic environment will permit identifying pathways important for induction of diverse stem cells toward the cardiac phenotype. Phenotypic characteristics of cardiac cells are their contractile and electrical properties. The objective of the present study was to define whether calcium (Ca þþ ) has a regulatory role in the pluripotential precursor cell population during commitment into cardiomyocytes. We used the chick embryo model because of ease of staging the embryos and visibility of heart development. Using the Ca þþ indicator Fluo-3=acetoxymethyl and confocal microscopy, we demonstrated the existence of higher free Ca þþ levels in the cardiogenic precursor cells than in neighboring cell populations outside of the heart fields. Subsequently, gastrulation stage 4=5 chick embryos were set up in modified New cultures in the medium containing either the L-type Ca channel blocker, diltiazem, or the N-type Ca channel inhibitor, x -conotoxin. The embryos were incubated for 22-24 h during which time the control embryos developed, beating looping hearts. At the end of incubation, exposure to the L-type channel blockade with diltiazem resulted in an inhibition of cardiomyogenesis in the most posterior, uncommitted, part of the heart fields. N-type channel blockade with x -conotoxin was less intense. Cells in the most anterior cardiogenic regions that were already committed at time of exposure continued to differentiate. Thus, regulation and maintenance of normal cytosolic Ca levels are necessary for the early steps of cardiomyocyte specification and commitment leading to differentiation.

High-content phenotypic assay for proliferation of human iPSC-derived cardiomyocytes identifies L-type calcium channels as targets

“…Given the immature state of hiPSC-CMs, further studies are needed to test whether LTCC blockers enhance adult CM proliferation in vitro and in vivo, which would be aided by the favorable pharmacokinetic properties of these drugs. While LTCCs have not previously been described to regulate CM proliferation, LTCC blockade has been shown to suppress CM differentiation and maturation [46,47]. Several miRNAs have been reported to regulate CM proliferation [19,37].…”

Capturing structure and function in an embryonic heart with biophotonic tools

“…Thus, assessment of cardiac impulse initiation and conduction is important in analyzing the coordination of the complex contraction patterns throughout the developing heart that have a profound effect on mechanical properties throughout the heart and vasculature such as stretch, strain, pressure, and shear force. Another consideration is that calcium fluxes associated with electrical activation is critical for signaling early steps in cardiogenesis (Linask and Linask, 2010 ). Electrical impulses are also implicated in regulating cell shape and consequently cardiogenesis (Chi et al, 2010 ).…”

Connecting teratogen‐induced congenital heart defects to neural crest cells and their effect on cardiac function

“…Increasing or decreasing the viscosity of the blood that would impact blood flow and shear force (Lucitti et al, ; Vermot et al, ) also results in cardiac defects. Disturbing the electrical activation of the heart can also alter cardiac development (Chi et al, ; Linask and Linask, ).…”