Figure 2: Cardiomyocytes and fibroblast states in control, DCM, and ACM ventricles.

(A) UMAP depicting CM states in all tissues. (B) Control and disease LVs and RVs abundance analyses for vCM1.1 (upper panel) and vCM1.2 (lower panel). (C) Single-molecule RNA fluorescent in situ hybridization exemplifies decreased SMYD1 (red) expression in CMs (identified by TNNT2 transcripts, cyan) within a DCM heart with a PV in PLN (phospholamban). Cell boundaries, WGA-stained (green); nuclei DAPI-stained (blue); bar 10μm. Quantified expression (spots per CM) and p-values from four independent control and disease LVs with PVs were assessed. (D) Immunohistochemistry validated decreased SMYD1 (red) protein in CMs (identified by troponin T staining, Fig. S6E) in TTN LV section. Cell boundaries, WGA-stained (green); nuclei DAPI-stained (blue); bar 10μm. Quantified protein levels (intensity per CM) and p-values were assessed from five independent control and DCM LVs with PVs. (E) Single-molecule RNA fluorescent in situ hybridization demonstrated increased expression of FNIP2 (red). CMs, nuclei, and cell boundaries are labeled as in C; bar 10μm. Quantified expression of FNIP2 (spots per CM and H-score; Methods) and p-values reflect analyses of two independent control and PKP2 samples. (F) UMAP depicting FB states. (G) Hydroxyproline assay (HPA) quantifies cardiac collagen content for each genotype. (H) Control and disease LVs and RVs abundance analyses for vFB2 (upper panel) and vFB3 (lower panel). (I) Pathway score of TGFβ activation in LV vFB2. (J) Single-molecule RNA fluorescent in situ hybridization shows decreased expression of CCL2 (red) in vFB3 (DCN, cyan) in disease compared to controls. WGA-stained (green); Nuclei DAPI-stained (blue); bar 10μm. Dot plot illustrating fold-change (log2FC) and significance (−log10(FDR)) of CCL2 expression in LV vFB3 across genotypes.