Changes of Gene Expression Profile during Differentiation of Equine Bone Marrow-Derived MSCs towards Adipocytes and Chondrocytes*

Abstract Mesenchymal stem/stromal cells (MSCs) have unique self-renewal and developmental potential resulting from their multipotency – the ability to differentiate into particular cell types. MSCs have great potential and outstanding therapeutic effects in various clinical treatments because of their ability to differentiate into ectodermal, endodermal, and mesodermal cell lines. This study aimed to identify changes in the MSC transcriptome profile during the process of losing multipotency and acquiring the ability to differentiate cells into adipocytes (adipose-derived MSCs, ADMs) and chondrocytes (chondrocyte-derived MSCs, CDMs), which are equine primary cells. Bone marrow-derived MSCs were differentiated into adipocytes and chondrocytes using cell-specific induction protocols. Transcriptome analysis was performed using NGS transcript sequencing. A comparison of the gene expression profiles between MSCs and ADM or CDM primary cells revealed 2325 and 803 differentially expressed genes (DEGs), respectively. The transformation of MSCs into adipocytes is directly linked to the regulation of Gene Ontology (GO) terms, such as fat cell differentiation, which is supported by 47 DEGs and adipocyte development GO terms. The results revealed the top DEGs involved in differentiation into adipocytes and previously established as related to adipogenesis: MEOX1 and CYYR1 were downregulated and CYP24A1 , LEP , TBX5 , FABP4 and GPER1 were upregulated. The obtained data revealed mechanisms that are altered during equine cell remodelling towards chondrocyte differentiation. One of the identified GO terms was the ossification process, represented by 35 DEGs, with the greatest upregulation of the IHH and PHOSPHO1 genes involved in chondrocyte proliferation and matrix mineralization, respectively. The results of this study suggest that a radical change in cell fate may influence gene expression and highlight the need for further research into efficient procedures for generating MSC-derived reprogrammed cells with potential applications in regenerative medicine.