.ROLE OF P38-MAPK DURING DIFFERENTIATION OF MUSCLE CELLS BY Solanum glaucophyllum LEAF?S EXTRACTS.

BUITRAGO C; GONZÁLEZ-PARDO, VERÓNICA; A. PAULA IRAZOQUI; DE GENARO, PABLO

Congreso; XXXIV Reunión Anual Asociación Argentina de Osteología y Metabolismo Mineral (AAOMM).; 2017

Glycoside derivatives of 1,25(OH)2D3 from plants can be gradually release to 1,25(OH)2D3 by endogenous animal tissue glycosidases. Here, we evaluate MAPKs and genes regulation role in C2C12 murine skeletal muscle cell differentiation by 1,25(OH)2D3-glycosides from Solanum glaucophyllum leaves extract (SGE) compared to synthetic 1,25(OH)2D3. Western blot results from time-course assays upon synthetic 1,25(OH)2D3 (1 nM) or SGE (10 nM) on C2C12 cells indicates that ERK1/2 phosphorylation rises significantly at the first hour of differentiation in treated conditions and falls at 48 h in 1,25(OH)2D3-treated cells, but not in cells exposed to SGE. p38 phosphorylation rises in a biphasic manner at 1 and 24 h of either 1,25(OH)2D3 or SGE treatment. JNK1/2 phosphorylation is significantly down-regulated at 48 h by both compounds. p38 inhibitor, SB 203580, abolishes myoblasts differentiation induced by synthetic 1,25(OH)2D3 or SGE. Gene?s expression was studied during differentiation phase by qRT-PCR. As expected, myoD1 mRNA control levels remained low throughout the period of analysis and increases upon 1,25(OH)2D3 or SGE treatment, whereas MHC2b mRNA expression, a late differentiation marker, rises at 72 h. mRNA of c-fos, starts to increase at 6 h, with maximum effect at 24 h, while junB significantly diminished between 1 and 24 h of 1,25(OH)2D3 or SGE treatment. egr-1 mRNA expression falls similarly to junB, whereas c-myc falls later than junB. Taken together, these results suggest that SGE, as 1,25(OH)2D3, promotes myotube formation through p38 activation. However, the significance of gene variation during this process needs clarification.