Characterisation and differentiation of porcine ovarian theca-derived multipotent stem cells

In this study, the cellular properties and in vitro differentiation capacity of porcine ovarian theca-derived multipotent stem cells (TSCs) were examined. Isolated TSCs were expanded into a homogeneous population that had a typical fibroblast-shaped morphology and was positive for alkaline phosphatase activity. Cell cycle analysis indicated that TSCs had high proliferative potential. Flow cytometry analysis demonstrated expression of mesenchymal cell surface markers (CD29, CD44 and CD90) on TSCs. Among three pluripotent markers tested (OCT4, NANOG and SOX2), only SOX2 was expressed in TSCs at protein and mRNA levels. Cytochemical staining demonstrated that TSCs differentiated in vitro into osteocytes and adipocytes. Lineage specific transcripts expressed by differentiated osteocytes including osteonectin, osteocalcin and RUNX2. Lineage specific transcripts expressed by differentiated adipocytes included adipocyte fatty acid binding protein-2 (aP2) and peroxisome proliferator-activated receptor-γ2. Following induction in oogenesis media, TSCs exhibited sequential changes in morphology, resembling oocyte-like cells (OLCs), and expressed transcription factors (OCT4, NANOG and SOX2), oocyte-specific marker genes (GDF9B, C-MOS, DAZL, VASA, ZPC, SCP3 and STELLA) and the folliculogenesis marker follicular stimulating hormone receptor. These results indicated that TSCs derived from ovarian follicles are capable of differentiating into mesenchymal lineages and OLCs.