EXTRACELLULAR VESICLES RELEASED FROM MESENCHYMAL STROMAL CELLS INDUCE TREG GENERATION AND PROTECT FROM IMMUNE-MEDIATED GLOMERULAR INJURY IN LUPUS NEPHRITIS
- Vincenzo Cantaluppi, Italy
Abstract
Background and Aims
Mesenchymal stromal cells (MSC) exert immunomodulatory and regenerative effects by releasing paracrine mediators including extracellular vesicles (EV), nanoparticles involved in cell-to-cell communication through transfer of proteins, mRNA and microRNA. The aim of this in vitro study was the evaluation of MSC-EV in T regulatory cell (Treg) generation and inhibition of glomerular cell alterations observed in lupus nephritis (LN).
Methods
EV were characterized for size, protein and RNA content after MSC supernatant ultracentrifugation. The effects of EV were studied on: 1) T cells isolated from peripheral blood and co-cultured with B cells purified by spleen of matched donors; 2) human glomerular endothelial and mesangial cells cultured in presence of anti-dsDNA containing sera drawn from LN patients.
Results
MSC-EV sized 60-150 nm and carried different microRNA and mRNA including the immunoregulatory Foxp3, Tim-1 and thrombospondin-1. EV were internalized in T cells inhibiting proliferation induced by PHA/ionomycin or by co-culture with spleen-derived B cells. EVs horizontally transferred to T cells Foxp3 mRNA inducing a Treg phenotype: EV-induced Tregs decreased T cell proliferation. MSC-EV also induced a regulatory phenotype in B cells (increased Tim-1 expression). EV were internalized in glomerular endothelial and mesangial cells inducing a significant decrease of LN sera-associated alterations. Indeed, MSC-EV reduced the release of TNF-alpha, IL-6 and MCP-1, endothelial-to-mesenchymal transition, inflammatory cell adhesion and fibrosis.
Conclusions
MSC-EV exert tolerogenic and regenerative effects by inhibiting T cell proliferation, inducing T/B cell regulatory phenotypes and protecting glomerular cells from LN sera-associated injury. MSC-EV could be evaluated as therapeutic strategy in LN and other autoimmune diseases.