Figure 3. TnC from the tissue microenvironment is required for MuSC function.

(A) scRNA-seq analysis of TnC expression at 5 DPI TA muscles of adult WT mice. Data originally from Oprescu et al., 2020.

(B, C) TnC mRNA expression dynamics in MuSC and FAPs from uninjured and regenerating TA muscles at different DPIs (0.5 – 21). Data originally from Oprescu et al., 2020.

(D, E) TnC mRNA expression dynamics in MuSC and FAPs in uninjured and at 3 and 7 DPIs with qPCR.

(F, G) Sender-Receiver Probability Heatmap of the tenascin signaling network in uninjured and 5 DPI TA muscles. Data originally from Oprescu et al., 2020.

(H, I) Chord diagrams representing incoming signaling to MuSC in uninjured and 5 DPI TA muscles. Data originally from Oprescu et al., 2020.

(J) IF images representing the contribution of transplanted RFP-labeled WT MuSC from adult 3 months old donor mice to regenerating TA muscles of WT or TnC-KO age-matched recipient mice (regenerating fibers – RFP, red, DAPI blue) (Scale bar= 50 µm) and quantification of RFP+ myofibers (n≥3 mice).

(K) Representative IF images of WT MuSC/WT FAP co-cultures from adult mice (Pax7, green; TnC, red; DAPI, blue). Yellow arrows indicate TnC in MuSC. Scale bar= 50 µm.

(L) Representative IF images of WT MuSC monocultures (Pax7, red; DAPI blue) (scale bar= 50 µm) and co-cultures of MuSC and FAPs from WT and TnC-KO adult mice (Pax7, green; TnC, red; DAPI, blue) (Scale bar= 50 µm). Quantification of Pax7+ cells normalized on WT MuSC monoculture.

Data are represented as mean ± SEM; **p<0.01, ***p<0.001, one-way ANOVA (D, E), *p<0.05, t test (J), *p<0.05, one-way ANOVA (L).