Whole Genome Transcriptional Analysis of Cd4⁺ and Cd8⁺ T-Lymphocyte Immunomodulated by Mesenchymal Stromal Cells

Recently, several researchers have showed that mesenchymal stromal cells (MSCs) are useful for preventing and treating the graft versus host disease, however the molecular mechanisms involved in immunomodulation of T lymphocytes by MSCs remains to be explored.

With that in mind, we performed a whole genome microarray study to explore transcriptional differences in activated TCD4 and TCD8 lymphocytes immunomodulated or not by MSCs.

Peripheral blood CD3+ T lymphocytes from 3 individuals were activated by anti-CD3/CD28 beads and cultured either in the absence or in the presence of MSC (5 to 1 ratio). Following a 5 day period, CD4⁺ and CD8⁺ lymphocytes cultivated or not with MSCs were immunomagnetically purified to over 95% purity (flow cytometry) and profiled by whole genome microarrays. Differentially expressed genes were analyzed in search of regulatory networks and levels of selected transcripts were evaluated by RT-PCR.

T lymphocytes proliferation was inhibited significantly by MSC (BrdU incorporation assay) and induced the expression of classical regulatory T cell genes (IL10, FOXP3, CTLA-4 and GITR). Our microarray analyses revealed that lymphocytes cultured with MSCs displayed several transcriptional modifications related to distinct signaling pathways. Among them, TCR signaling, cell cycle (G1/S progression), NF-kB pathway, mTOR signaling and in enzymes and factors related with chromatin modification and remodeling. An insignificant number of transcript behaved distinctly (eg. with changes in opposite direction) when TCD4⁺ and TCD8⁺ lymphocytes where compared.

Our results clearly show that both CD4⁺ and CD8⁺ T lymphocytes are immunomodulated by MSCs by similar mechanisms and this effect occurs by means of distinct molecular mechanisms. Supported by FAPESP, CNPq and FINEP.

No relevant conflicts of interest to declare.