Immune modulation via adipose derived Mesenchymal Stem cells is driven by donor sex in vitro

Flyn Mckinnirey,Graham Vesey,Sharon Mccracken,Benjamin Herbert

doi:10.1038/s41598-021-91870-4

Abstract

Mesenchymal stromal/stem cells (MSCs) are currently being used in clinical trials as proposed treatments for a large range of genetic, immunological, orthopaedic, cardiovascular, endocrine and neurological disorders. MSCs are potent anti-inflammatory mediators which are considered immune evasive and employ a large range of secreted vesicles to communicate and repair damaged tissue. Despite their prolific use in therapy, sex specific mechanism of action is rarely considered as a potential confounding factor for use. The purpose of this study was to examine the potency and functionality of both female and male adipose derived MSCs in order to gain further insights into donor selection. Methods MSC were expanded to passage 4, secretome was harvested and stored at − 80c. To assess potency MSC were also primed and assessed via functional immune assays, ELISA, multiplex and immunophenotyping. Results Female MSCs (fMSC), consistently suppressed Peripheral blood mononuclear cell (PBMC) proliferation significantly (p < 0.0001) more than male MSC (mMSC). In co-culture mPBMCs, showed 60.7 ± 15.6% suppression with fMSCs compared with 22.5 ± 13.6% suppression with mMSCs. Similarly, fPBMCs were suppressed by 67.9 ± 10.4% with fMSCs compared to 29.4 ± 9.3% with mMSCs. The enhanced immunosuppression of fMSCs was attributed to the production of higher concentrations of the anti-inflammatory mediators such as IDO1 (3301 pg/mL vs 1699 pg/mL) and perhaps others including IL-1RA (1025 pg/mL vs 701 pg/mL), PGE-2 (6142 pg/mL vs 2448 pg/mL) and prolonged expression of VCAM-1 post activation relative to mMSCs. In contrast, mMSCs produces more inflammatory G-CSF than fMSCs (806 pg/mL vs 503 pg/mL). Moreover, IDO1 expression was correlated to immune suppression and fMSCs, but not mMSCs induced downregulation of the IL-2 receptor and sustained expression of the early T cell activation marker, CD69 in PBMCs further highlighting the differences in immunomodulation potentials between the sexes. Conclusion In conclusion, our data shows that female MSC are more potent in vitro than their male counterparts. The inability of male MSC to match female MSC driven immunomodulation and to use the inflammatory microenvironment to their advantage is evident and is likely a red flag when using allogeneic male MSC as a therapeutic for disease states.

Highlights

Mesenchymal stem/stromal cells (MSC) are a multi-potent, multifunctional cell type that are defined by their capability to proliferate, renew, differentiate and regenerate[1]
MSC doubling per day and total doublings showed no significant differences between the donors up to passage 4 (Fig. 1a) and all MSCs showed a fibroblastic like morphology
To test for difference in the immunosuppressive properties of MSCs derived from males and females, MSCs were used to alter Peripheral blood mononuclear cell (PBMC) proliferation

Summary

Introduction

Mesenchymal stem/stromal cells (MSC) are a multi-potent, multifunctional cell type that are defined by their capability to proliferate, renew, differentiate and regenerate[1]. The most well documented function of MSC is their immunosuppressive and immunomodulatory characteristics which, when administered as treatment have been shown to provide safe and acute relief and can potentially have long lasting effects. The challenges associated with in vivo MSC efficacy potentially stem from a deeper set of characteristics such as donor and recipient age, secretion profile, homing capability, clearance rates, culture conditions, cryopreservation techniques and perhaps a rarely noted link to efficacy, donor and recipient sex[13,14,15,16]

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Conclusion