INVESTIGADORES
BUITRAGO Claudia Graciela
congresos y reuniones científicas
Título:
Comparative actions of 1α,25(OH)2D3-glycosides and synthetic 1α,25(OH)2D3 during miogénesis
Autor/es:
AMUSQUIVAR A; A. PAULA IRAZOQUI; DE GENARO PABLO; GONZALEZ PARDO V; BUITRAGO C; RUSSO DE BOLAND A; BACHMANN H
Reunión:
Congreso; Reunión Anual de la Sociedad Argentina de Investigaciones Bioquímicas y de Biología Molecular (SAIB); 2016
Resumen:
Solanum glaucophyllum leaf?s extracts (SGE) enriched with 1,25(OH)2D3-glucosides are available for the organism due to the presence of endogenous glycosidases. We have previously shown that SGE exhibits at least equal or greater effects on early myoblast differentiation as synthetic 1,25(OH)2D3 thus being an effective substitute to promote muscle growth. We further investigated the effects of SGE compared to synthetic 1,25(OH)2D3 studying the regulation of mitogen activated protein kinases (MAPKs) and genes involved on the differentiation of murine skeletal muscle cells, C2C12, and their role on myotube formation. Time course (1-48 h) experiments were performed to evaluate MAPKs phosphorylation upon synthetic 1,25(OH)2D3 (1 nM) or SGE (10 nM) on C2C12 cells. While ERK 1/2 phosphorylation increases during the early proliferation phase, it remains unchanged under control or treated conditions up to 24 h during differentiation. It then decreases at 48 h in control and in 1α,25(OH)2D3 treated cells, but not in cells exposed to SGE. p-38 phosphorylation increases the first hour of 1α,25(OH)2D3 or SGE treatment and then remains unchanged through time. p38 MAPK inhibitor, SB 203580, abolishes myoblasts differentiation induced by synthetic 1α,25(OH)2D3 or SGE. We have also studied the gene expression pattern of myoD1, c-fos, junB, c-myc, erg-1 and MCH2b during the differentiation phase (1-72 h) by qRT-PCR. As expected, myoD1 mRNA control levels remained decreased throughout the period of analysis and increased upon 1α,25(OH)2D3 or SGE treatment, whereas MHC2b mRNA expression, a late differentiation marker, increases at 72 h compared to control. The immediately early gene c-fos, increases between 6 and 24 h, while junB significantly diminished at 24 h of 1α,25(OH)2D3 or SGE treatment. Furthermore, egr-1 mRNA expression decreased similarly to junB, whereas c-myc decreased later than junB of both treatments. Taken together, these results suggest that SGE, at higher concentration than synthetic 1α,25(OH)2D3, promotes myotube formation through p38 MAPK activation. However, the significance of gene variation during this process needs clarification.