Fig 1: Characterization of the high-VEGF-A secreting MSC subpopulation.a, Scatter plot of the transcript to VEGF-A secretion correlation for all genes from SEC-seq experiments for normoxic and hypoxic MSCs from Figure 3. The 10 most highly correlating genes based on both experiments are labeled. b, Table giving the ranking (based on average correlation), gene name, correlation to secretion in normoxic and hypoxic cells, and the average of those two values for the ten top genes from (a). c, UMAPs showing VEGF-A secretion levels and expression of 5 select correlated genes from (b) in normoxic and hypoxic MSCs from Figure 3. The VEGF-A secretion UMAP is given from Fig. 3c for comparison. d, As in (c), for a separate SEC-seq experiment performed on MSCs in the normoxic culture condition. e, Cell clusters projected onto the UMAP of the replicate SEC-seq experiment f, Heatmap of the top 10 differentially expressed genes from each cluster (indicated on top) of the SEC-seq experiment in (c,d) (rows=genes, columns=individual cells). Displayed at the top are the log transformed VEGF-A secretion and VEGFA transcript levels. Right: top 3 genes differentially expressed gene for each cluster. g, Heatmap of the top GO terms found for all of the differentially expressed genes from the clusters in (e). The (–logP) value indicates if the term was enriched for a given cluster. h, Venn diagram showing the overlap of differentially expressed genes from the highly secreting cluster in 3 SEC-seq experiments (top left: normoxic MSCs from (3b), top right: hypoxic MSCs from (3b), bottom: normoxic MSCs from (4e)). Overlapping genes form the Vascular Regenerative Signal (VRS). i, Gene ontology analysis for VRS genes from (h). Similar terms were collapsed. j, Average of the normalized transcripts level of VRS genes per cell, displayed for the SEC-seq experiment in (e) and (3b). k, As in (j), for MSCs loaded in oligo-barcoded nanovials (see Fig. 2j-l). l, As in (j), for a standard scRNA-seq experiment on unsorted, suspended MSCs. m, Comparison of gene type classification for VRS genes and genes differentially expressed in all clusters in (e) except for those from cluster c5. n, Enrichment of possible TF regulators of the VRS genes based on the TRRUST database. o, Consensus rank of VEGF-A secretion to gene correlation based the SEC-seq experiments used in (h), with red dots displaying all VRS genes. p, Schematic depicting the heterogeneity of VEGF-A secretion in MSCs under normoxic and hypoxic conditions, highlighting the importance of the VRS genes for marking high VEGF-A secretion.