MicroRNAs as prognostic markers for chondrogenic differentiation potential of equine mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are a promising cell source for cartilage tissue regeneration in animals and humans but with large inter-donor variation in their in vitro chondrogenic differentiation potential. Underlying molecular mechanisms responsible for culture-expanded MSC heterogeneity remains poorly understood. In this study, we sought to identify variations in miRNA signatures associated with cultured equine MSC chondrogenic differentiation potential from different donors. Neocartilage tissue generated from equine cord blood-derived MSCs (CB-MSCs) was categorized as having either high or low chondrogenic potential based on their histological appearance and quantification of glycosaminoglycan deposition. Using next-generation sequencing, we identified 30 differentially expressed miRNAs amongst undifferentiated MSC cultures that corresponded with their chondrogenic potential. Of note, MSCs with low chondrogenic potential upregulated miR-146a and miR-487b-3p, which was also observed by qRT-PCR. Our findings suggest that miRNA profiling of equine MSC cultures may have prognostic value in selecting MSC donors with regards to their chondrogenic differentiation potential.