Fig. 6: PIBF1 facilitates the manifestation of cardiovascular features in human heart organoids.

a Schematic diagram of differentiation from iPSC into hHO and application of rsPIBF. b Immunostaining of cTnT, CD31, and PDGFRβ in rsPIBF-treated hHO. n = 16, 21 (cTnT), n = 13, 15 (CD31), n = 8, 7 (PDGFRβ) in each group. c Immunostaining of cTnT and α-actinin in rsPIBF-treated hiPSC-derived 2D-cultured cardiomyocytes. n = 8 per group. d Multi-electrodes array (MEA) in rsPIBF-treated hHOs. FPD, field potential duration. n = 3-4 per group. e Sprouting assay of rsPIBF-treated hHOs. Sprouts were viewed as phase-contrast and PDGFRβ-stained images. n = 7-8 per group. Scale bar: 100 μm. f Expression pattern of significantly up-or down-regulated genes in sPIBF-treated hHO compared to the non-treated group was visualized using a heatmap. Two clusters of genes were identified by hierarchical clustering based on their expression patterns, and representative GO terms of each cluster were visualized using a barplot (width and color of the bars indicate gene ratio and p-value, respectively). EB, embryonic body. g The top 5 enriched GO terms (big dots) on significantly up-regulated genes by sPIBF treatment were visualized with their associated genes (small dots). The size of big dots indicates the number of associated genes. The color of small dots indicates the binary logarithm of the fold change of the genes by sPIBF treatment. The lines connecting the GO term and the associated gene were uniquely colored by the GO term. The intensity of fluorescence-labeled cells (b, c) and sprout length data (e) are expressed relative to control. Data are presented as mean ± SEM (b-e); *P < 0.05; ***P < 0.001; ****P < 0.0001 in two-sided Student’s t-test (b-e). The n number represents biologically independent hHOs in each group. Source data are provided as a Source Data file.