Cytotherapy | 2019
Enhanced immunomodulatory profile of infrapatellar fat pad (IFP)-derived MSC after inflammatory priming, 3D spheroid culture and CD146 selection: a cellular alternative for bone marrow (BM) in orthopedics
Abstract
Backgrouind & Aim Mesenchymal Stem Cells (MSC) exhibit immunomodulatory properties, making them an alternative to treat inflammation-related musculoskeletal conditions. We have identified a CD146-based subset of BM-MSC with enhanced immunomodulatory effects. IFP-MSC have been proposed as an alternative to BM-MSC. Here, we assessed unfractionated and CD146-selected IFP-MSC s secretory response to inflammation (priming) in 2D and 3D spheroids and functional immunomodulatory effects, all contrasted to BM-MSC. Methods, Results & Conclusion Methods Human BM- and IFP-MSC chondrogenic potential and comparative immunophenotype, growth kinetics and key transcripts before and after inflammatory priming (IFNγ/TNFα) were assessed in 2D. Inflammation-related multiplex secretome was interrogated in 2D and 3D spheroids. Fractionated MSC (CD146Pos C members of IGF family increased only in IFP-MSC; AR and NT3/NT4 up in IFP and down in BM-MSC. 3D spheroids resulted in a sustained increase in CD146 expression and protein presence (IHC), with enhanced inflammation-related secretome in primed IFP-MSC compared with BM-MSC, especially the immunosuppressor IDO. Fractionation both cells types (CD146) further increased IDO expression while reduced pro-inflammatory IL-6 and IL-8 in primed CD146Poscells, more pronounced in IFP-MSC. Finally, primed CD146Poscells strongly abrogated proliferation of activated human PBMCs in a dose-dependent manner, outperforming unfractionated cells at large PBMCs:MSC ratios and CD146Negcells at all doses, suggesting CD146Pos as the actual immunomodulatory subset. Conclusion Inflammatory priming, spheroid cultures and CD146-enrichment result in a significantly enhanced immunomodulatory properties of human IFP-MSC, thus evolving in a viable alternative for cell-based therapy protocols in Orthopedics.