INTER-DONOR VARIABILITY AND CELLULAR PROLIFERATION: THEIR IMPACT ON THE IMMUNOMODULATORY STRENGTH OF ADIPOSE-DERIVED MESENCHYMAL STEM CELLS IN T CELL-MEDIATED HEPATITIS

Abstract

Background & Aim

Mesenchymal stem cells (MSCs) are recognized for their numerous therapeutic benefits, notably for their immunomodulatory capabilities. Thus, they are being tested in many clinical trials, including those for GVHD and osteoarthritis. However, MSCs are also known to be highly heterogeneous. In addition to originating from various tissue sources, they also exhibit inter-donor variation within the same tissue, making it hard to standardise MSC therapeutics. Hence, our aim is to improve this by investigating donor variability and the link to their immunomodulatory strength.

Methods, Results & Conclusion

We tested this using both in-house produced and commercially sold adipose-derived MSCs (AD-MSCs) via the Concanavalin A hepatitis animal model. In both sets of AD-MSCs, we indeed observed varying levels of anti-inflammatory effects across different donors. Microarray analysis on our in-house AD-MSCs revealed donors with stronger effects exhibited activation in cell cycling and proliferation pathways. Single cell transcriptomic analysis on the commercially sold AD-MSCs, however, showed all donors merging into one group regardless of effect strength, indicating a high level of similarity in MSC characteristics. Further examination through cell clustering revealed 12 distinct subclusters that made up different percentages within each donor, suggesting that subtle cell population differences play a crucial role in differentiating AD-MSCs with strong and weak anti-inflammatory effects. Gene ontology analysis on the differentially expressed genes (DEGS) from clusters representing donors with strong effects demonstrated changes in cell proliferation, echoing the results of the in-house AD-MSC microarray analysis. When we assessed the in vitro doubling time (DT) and cell growth in both sets of AD-MSCs, we observed that donors with stronger anti-inflammatory effects indeed exhibited lower DT and higher growth rates. In summary, this study is the first to link the in vivo immunomodulatory effects of different donors to bulk and single cell transcriptomics, with results indicating a positive correlation between cell proliferation and effect strength. Our ongoing research includes further dissecting target subclusters within each donor and identifying common DEGs between both in-house and commercial AD-MSCs that could serve as reliable Critical Quality Attribute (CQA) markers. This will hopefully lead to better standardisation and development of more effective AD-MSC therapeutics.