EV-induced signalization in BM-MSCs. (A) Analysis of transcription factor enrichment in the promoters of EV (left) or TNF/LT (right) upregulated genes performed with HOMER. Represented are significant motifs. (B) Enrichment for transcription factor targets in EV (left) or TNF/LT (right) upregulated genes as determined with TRRUST database with EnrichR Web site. The Top20 enriched transcription factors were represented as dot plots. (C) A TGF-β sensor cell line was stimulated overnight by TGF-β1, EVs from the RL cell line (FL EVs), or pooled EVs from tonsil B cells (TONS EVs) in the presence or not of the TGFBR1 inhibitor galunisertib (Gal). GFP expression was determined by flow cytometry and expressed as the mean fluorescence intensity (MFI). Shown are 4 independent experiments with 1 example of a representative data in the histogram. (D) Evaluation of SMAD2/3 and p38 phosphorylation by flow cytometry after a 6-hour stimulation by RL EVs in comparison with untreated (UNT) cells. Shown is one representative experiment out of 3. (E) Analysis by qPCR of BM-MSCs (n = 6) treated by RL EVs ± TGFBR1 inhibition with galunisertib. Results are expressed as median fold change of untreated BM-MSCs. (F) Analysis by qPCR of BM-MSCs (n = 6) treated with EVs from purified tonsil B cells. Results are expressed as median fold change of untreated BM-MSCs.