Uncovering the bequeathing potential of apoptotic mesenchymal stem cells via small extracellular vesicles for its enhanced immunomodulatory and regenerative ability.

Abstract

Background: Mesenchymal Stem Cells-derived Small Extracellular Vesicles endowed with regenerative cargo from their parent cells, have emerged as a promising avenue for cell-free therapeutics in regenerative medicine. Notably, deliberate induction of apoptosis in MSCs before sEV isolation has been identified as a strategy to augment the regenerative capabilities of MSCs-sEVs. This study explores a novel approach to enhance the immunomodulatory potential of MSC-sEVs through apoptosis induction and optimal tissue source to ensure consistent and improved clinical outcomes.

Methods: Apoptosis was induced in tissue-specific MSCs using Staurosporine. sEVs^V and sEVs^Apo were isolated via ultracentrifugation. Invitro immune response was assessed via T-cell proliferation, T-regulatory cell induction & macrophage polarization assay. Mitochondrial bioenergetics was studied using MitoSOX staining and Seahorse assay in H2O2-treated HuH7 cells. These findings were validated invivo in the CCL4-induced Chronic Liver Disease model via Histopathological staining, biochemical parameters, and fibrotic, pro-inflammatory, and anti-inflammatory markers and assessed the mechanism by targeting TGF-β/SMAD pathway.

Results: Our results demonstrate that sEVs^Apo exhibited significantly higher concentrations and superior immunomodulatory effects by suppressing CD3 + T-cell proliferation, promoting T-regulatory cell differentiation, and polarized macrophages towards M2-phenotype. In terms of tissue specificity, it was observed that WJ-sEVs were faring better. sEVs^Apo effectively reduced mitochondrial ROS & significantly improved oxidative phosphorylation. Invitro findings were corroborated in an invivo CLD model, wherein sEVs^Apo ameliorated fibrosis and inflammation, by inhibiting TGF-β/ SMAD2/3 pathway.

Conclusion: This study concludes that apoptosis induction can be considered as minimum manipulation strategy to enhance the immunoregulatory and regenerative potential of MSCs-sEVs, thereby expanding their implication in immune disorder.