Figure 4. TnC signals through Annexin A2 to maintain MuSC in quiescence.

(A) Violin plots depicting the different expression dynamics AnxA2, Pax7, and Pdgfra at different DPIs (0, 3.5, 5, 21) in MuSC and FAPs (online available dataset).

(B) Western blot analysis for Annexin A2 on TnC-immunoprecipitated 5 DPI TA muscle protein lysate samples.

(C) Validation by immunofluorescence (IF) of Annexin A2 expression in WT MuSC in vitro (Pax7, green; Annexin A2, red; DAPI, blue) (Scale bar= 20µm).

(D) Dot plot representing the changes in the relative expression of TnC and the percentages of TnC expressing cellpopulations within Pax7⁺/AnxA2⁺ and Pax7⁺/AnxA2⁻ MuSC and Pdgfra⁺/AnxA2⁺ and Pdgfra⁺/AnxA2⁻ FAPs in uninjured TA muscles and across different timepoints (3.5, 5, 21 DPI). Data originally from Oprescu et al., 2020.

(E) Representative IF images of GFP control and AnxA2 knockdown (KD) being treated or not with recombinant TnC (48h treatment) (GFP, green; Pax7, red; DAPI, blue) (scale bar= 50 µm) and quantification of Pax7⁺ cells normalized on non-treated GFP control MuSC (n=3, N_fov=30).

Data are represented as mean ± SEM; ****p<0.0001, one-way ANOVA (E).