Modulation of α-Actin and α-Actinin Proteins in Cardiomyocytes by Retinoic Acid during Development

Abstract

Early heart development is known to be sensitive to retinoid concentrations. Although the influence of retinoids on cardiac morphogenesis has been described previously, the effect of retinoids on cardiomyocyte differentiation during development has not been characterized. We quantified the effects of the retinoic acids all-trans RA and 13-cis RA on α-actin and α-actinin at the subcellular level in cultures of chick embryo cardiomyocytes obtained from Hamburger and Hamilton’s (HH) stage 22, 32 and 40 embryos. The retinoids increased the concentration of α-actin and α-actinin in the cytoplasmic and cytoskeletal fractions of cells at all three stages of development. The effect was greatest in cardiomyocytes treated for 24 h with all-trans RA and in cells from HH22 embryos. The greatest increases in α-actin concentration occurred in the cytoskeletal fraction of HH22 cells cultured for 24 h with all-trans or 13-cis RA, whereas the greatest increases in α-actinin were found in the cytoplasmic fraction of HH22 cells exposed to retinoids for 24 h. We conclude that retinoic acid plays a role in the reorganization of the pattern of sarcomeric protein expression during cardiomyocyte differentiation.

Microarray results suggest altered transport and lowered synthesis of retinoic acid in schizophrenia

“…8 That dysregulation of the retinoid cascade may be a contributory mechanism in schizophrenia 9 is supported by the observation that the genes coding for many of the proteins showing altered expression in this microarray study of schizophrenia prefrontal cortex are either directly or indirectly regulated by RA and retinoid receptors; for example, pyruvate kinase, muscle (PKM2), 10 mitochondrial aconitase 2 (ACO2), 11 hexokinase 1 (HK1) and malate dehydrogenase 1 (MDH1), 12 gelsolin (GSN), 13 neuron-specific enolase (ENO2), 14 cardiac muscle actin alpha (ACTC) and actinin, alpha4 (ACTN4), 15 and transferrin (TF). 16 The reliability of microarray studies reporting small differences in expression can be questionable, 17 particularly so in relation to false negatives due to the lack of resolution (hybridization without separation) and false positives due to a lack of sensitivity (multiplicity of probes; complexity of probes).…”

Release of muscle α-actin into serum after intensive exercise

“…It has been previously reported α-actin to be a novel and reliable marker of skeletal muscle damage in sportspeople, with a high sensitivity of 63.3-100% [3,22,23].…”

Milk growth factor (MGF) induces transformation into ATDC5 cells, prechondrocytes, and cooperates with retinoic acid to transform the cells into new forms

“…To evaluate the proliferate and transforming effects of MGF and RA on ATDC5 prechondrocytes, we analyzed their effects on proteoglycan, cell proliferation, induction of a-smooth muscle actin (a-SM-actin), which plays a key role in the differentiation of a variety of cell types (Aranega et al, 1999;Christen et al, 1999;Horiuchi et al, 1999), and induction of vimentin, which is expressed in fibroblasts (Sarria et al, 1990;Trevor et al, 1995) and carcinoma cells (Tsuru et al, 1990;Thompson et al, 1992;Islam et al, 2000), and is suppressed in leukemic cells by RA-induced differentiation (Lo Coco et al, 1991).…”