Priming of MSCs with inflammation-relevant signals affects extracellular vesicle biogenesis, surface markers, and modulation of T cell subsets

Abstract

Although considerable evidence exists supporting the use of mesenchymal stromal cells (MSCs) for treating immune diseases, successful clinical translation has been challenging and has led researchers to investigate cell-free alternatives. MSC-derived extracellular vesicles (MSC-EVs) have been shown to mediate a significant portion of the observed therapeutic effect, including immunosuppression. MSCs have been shown to respond to different aspects of the injury microenvironment such as inflammatory cytokines and hypoxia, although acidosis has not been investigated and different conditions have not been assessed in terms of their effects on MSC-EV function. This study investigated the effects of acidosis, hypoxia, and inflammatory cytokine priming on MSCs and MSC-EVs.We cultured MSCs in the presence of acidosis, hypoxia, or inflammatory cytokines (Interferon-gamma and Tumor Necrosis Factor-alpha) and compared the characteristics of their EVs as well as their uptake by and suppression of different T cell subsets. MSCs showed a greater effect on suppressing activated CD4 + and CD8 + T cells than MSC-EVs.However, MSC-EVs from MSCs primed with acidosis increased CD4 + and CD8 + regulatory T cell frequency in vitro. This functional response was reflected by MSC-EV uptake. MSC-EVs from acidosis-primed MSCs were taken up by CD4 + and CD8 + regulatory T cells at a significantly higher level than MSC-EVs from control, hypoxic, and inflammatory cytokine groups. These data suggest that a simple low-cost alteration in MSC culture conditions, acidosis, can generate extracelluar vesicles that have a desirable influence on anti inflammatory T cell subtypes.

Morphological landscapes from high content imaging reveal cytokine priming strategies that enhance mesenchymal stromal cell immunosuppression

“…These chemokines may recruit activated immune cells to be locally modulated by other secreted or cell contact-mediated factors. CXCR3 is involved in regulatory T-cell recruitment and migration as well, which could be another possible avenue for MSC immunomodulation (Andrews et al, 2021;Oo et al, 2010;Paust et al, 2016).…”

Extracellular vesicles from IFN-γ-primed mesenchymal stem cells repress atopic dermatitis in mice

“…MSCs interact with various lymphocytes and exert an immune regulatory role by secreting soluble factors and EVs [ 40 , 69 , 70 ]. Importantly, the immunomodulatory or tissue-reparative function of MSC-derived EVs can be largely affected by treatment with cytokines or growth factors [ 71 ]. IFN-γ is a soluble cytokine that belongs to the type II class of interferon, which is produced from various cells including T-cells, NK T cells, NK cells, macrophages [ 72 ].…”

Morphological Landscapes from High Content Imaging Identify Optimal Priming Strategies that Enhance MSC Immunosuppression

“…CXCR3 is involved in regulatory T cell recruitment and migration as well, which could be another possible avenue for MSC immunomodulation. 59–61…”

“…CXCR3 is involved in regulatory T cell recruitment and migration as well, which could be another possible avenue for MSC immunomodulation. [59][60][61] Secretion of DKK1, which inversely correlated with T cell suppression, is an inhibitor of canonical Wnt signalling 62 . PGE2, on the other hand, was positively correlated with MSC T cell suppression, and is a known activator of canonical Wnt signaling 63 .…”