Fig. 1.

Cardiac fibroblast (CF) lineages express Tcf21 and Postn tamoxifen-inducible Cre, and Wnt/β-catenin is activated after TAC. Tcf21 ^MCM ;R26 ^mTmG and Postn ^MCM ;R26 ^mTmG mice were subjected to TAC and Cre-activity was induced by TAM food from day 0 after operation. a GFP-labeled CFs (green) were observed in Tcf21 ^MCM ;R26 ^mTmG sham-operated hearts 2 and 8 weeks after TAC with continuous TAM. b GFP-labeled CFs were only observed in Postn ^MCM ;R26 ^mTmG after TAC but not sham-operated hearts. Scale bar = 100 µm. c Active and total β-catenin protein expression was determined by western blotting in GFP⁺ CF extracts isolated from Tcf21 ^MCM ;R26 ^mTmG mice 2 weeks after TAC or sham operations. β-catenin signaling activation was determined by the ratio of activated to total β-catenin protein. d Expression levels of the Wnt pathway downstream gene Axin2 in GFP + CFs isolated from Tcf21 ^MCM ;R26 ^mTmG 2 weeks after TAC or sham operations were determined by quantitative PCR relative to B2M. Data points are shown with median and interquartile ranges indicated. Statistical significance was determined using unpaired Mann–Whitney U tests: *P < 0.05. N = 4 mice per group