Fig. 2.

Long-term homeostatic responses to BMP9 are disturbed in the PAH lung endothelium. a Global transcriptome analysis (RNA-seq, n = 5) on MVECs receiving BMP9 for 90 min or 24 h. Differential gene expression was calculated in comparison to unstimulated samples. Venn diagrams illustrate the number of overlapping genes that pass the log2-fold threshold of ± 1 within control or PAH groups. Volcano plots visualize all genes passing the p value threshold of p ≤ 0.05 (dark grey dots). b Network graph resulting from unbiased Gene Set Enrichment Analysis (GSEA) in control (inner circle) and PAH MVECs (outer circle) at 24 h after BMP9 stimulation. Pathway activation was compared to unstimulated samples. Represented are positive (up-regulated, red circles), negative (downregulated, blue circles), and non-enriched pathways (white circles); gene overlap between pathways (green lines); and gene overlap with a pulmonary hypertension (PH) signature gene set (yellow triangle with magenta lines, overlap cut-off ≥ 5 genes). Thickness of lines indicates number of overlapping genes. c Heat maps of genes induced in endothelial-to-mesenchymal transition (EndMT). Shown are log2-fold changes in transcript levels following 90-min or 24-h BMP9 stimulation compared to basal samples. d RT-PCR validation of the EndMT master transcription factors SNAI1 and SNAI2. Box plots represent min, max, and median log2-fold changes after 24-h BMP9 compared to unstimulated conditions. Unpaired Student’s t tests were used to calculate p values