Xenbase Image ID: 150011

FIGURE 3. IGFBP-4 is required for the differentiation of P19CL6 cells into cardiomyocytes. a, Expression analysis of IGFBP family members by RT–PCR during DMSO-induced cardiomyocyte differentiation of P19CL6 cells (from day 0 to day 8). b, Left: knockdown of Igfbp4 in P19CL6 cells attenuated cardiac marker expression in response to treatment with DMSO. BP4-1 and BP4-2 represent two different siRNAs for IGFBP-4. Right: knockdown of Igfbp3 or Igfbp5 had no effect on cTnT expression in response to DMSO treatment. c, Treatment with a neutralizing antibody against IGFBP-4 (anti-BP4; 40 mug ml-1) attenuated DMSO-induced cardiomyocyte differentiation of P19CL6 cells. Error bars show s.d. d, IGFBP-4 immunostaining during DMSO-induced differentiation of P19CL6 cells stably transfected with alphaMHC–green fluorescent protein (GFP) reporter gene. Top left, IGFBP-4 staining (red); top right, GFP expression representing differentiated cardiomyocytes; bottom left, nuclear staining with DAPI (4',6-diamidino-2-phenylindole); bottom right, a merged picture. Scale bar, 100 mum. e, Attenuated cardiomyocyte differentiation of P19CL6 cells by Igfbp4 knockdown was rescued by inhibiting Wnt/beta-catenin signalling. Control and Igfbp4-knocked-down P19CL6 cells were transfected with an expression vector for GFP or LRP6N (a dominant-negative form of LRP6) and induced to differentiate into cardiomyocytes by treatment with DMSO. LRP6N overexpression rescued the attenuated cardiomyocyte differentiation induced by Igfbp4 knockdown as assessed by MF20-positive area (left panel), cardiac marker-gene expression and cTnT protein expression (right panel). Error bars show s.d. Image published in: Zhu W et al. (2008) Copyright © 2008. Image reproduced with permission of the Publisher, Macmillan Publishers Ltd. Larger Image Printer Friendly View

Return to previous page