Figure 4.

FZD4 Enriches CPC in the FLK1⁺PDGFRA⁺ Population, Increasing Subsequent CM Yield

(A and B) Cardiac output of sorted progenitor subpopulations based on CTNT abundance measured by flow cytometry (A; the number in the box represents the percent positive value) and immunofluorescence staining CTNT-expressing cells (green) and DAPI nuclear stain (blue) (B). Scale bars represent 500 μm.

(C) Quantified from flow cytometry, d7 CTNT⁺ percentage from d3.75 input CPC populations sorted using CPC-associated markers FLK1, PDGFRA, and FZD4. CTNT abundance is significantly higher in the FLK1⁺PDGFRA⁺FZD4⁺ population relative to both the FLK1⁺PDGFRA⁺ and FLK1⁺PDGFRA⁺FZD4⁻ population (mean ± SEM, n = 4 independent experiments, ^∗p < 0.05).

(D) (I) d3.75 (input) CPC marker abundance was correlated to the cardiomyocyte percentage (CTNT⁺) of the d7 (output) populations. (II) In the mock sorted d7 output, the CTNT abundance has a higher correlation with the FLK1⁺PDGFRA⁺FZD4⁺ input marker than FLK1⁺PDGFRA⁺. (III) FZD4 alone also exhibited a higher correlation than FLK1⁺PDGFRA⁺ with the output CTNT abundance in the mock sorted sample (n = 4 independent experiments, ^∗p < 0.05).