Osteogenic and adipogenic differentiation potential of an immortalized fibroblast-like cell line derived from porcine peripheral blood

Primary fibroblast-like cells isolated from the peripheral blood of a healthy pig were immortalized by transduction of cells with a replication-defective retrovirus vector expressing the E6/E7 proteins of human papillomavirus type 16 (pLXSN-16E6E7). The immortalized cells grow rapidly in cell culture and exhibit a distinct cell surface phenotype that was positive for CD90, CD44, collagen I, and vimentin and negative for CD14 and MHC II. Additionally, these immortalized blood derived-fibroblast-like cells had the potential to differentiate into osteoblasts and adipocytes in vitro as evidenced by the deposition of calcium, increased alkaline phosphatase activity, upregulated osteogenic and adipogenic marker gene expression, and accumulation of fat droplets in cells when osteogenic (dexamethasone, ascorbic acid, and β-glycerophosphate) or adipogenic supplements (dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin) were added to the culture. Overall, the results suggest that the immortalized blood-derived fibroblast-like cells exhibit some of the features of mesenchymal precursor cells, which may have implications in tissue repair and remodeling process.