Rapid isolation and expansion of skin-derived precursor cells from human primary fibroblast cultures

Skin-derived precursor (SKP) cells have self-renewal and multipotent abilities and are found in the dermis. SKP cells have been isolated previously from pre-established dermal fibroblast cultures. In these procedures, long-term culture and low yield remain the crucial aspects requiring improvement. In this study, we exposed pre-established dermal fibroblasts to 30-min acid stress prior to isolating SKP cells (termed pH-SKP) and compared the yield to the previously published trypsin- and no-stress methods. Spheroid formation was confirmed and analyzed at days 3, 5 and 7. Stemness was investigated by immunohistochemistry for the stem cell markers Nestin, CD9, vimentin and NG2. Multipotency was investigated by differentiation into adipocytes, smooth muscle cells and fibroblasts. The pH-SKP spheroid yield at day 5 was four- and threefold higher than those obtained using trypsin- and no-stress methods, respectively. The expression of stem cell markers Nestin, CD9, vimentin and NG2 were significantly expressed in pH-SKPs compared to the fibroblast origin. Successful pH-SKP spheroid formation and differentiation were achieved and validated in 11 distinct human primary fibroblast lines. These results demonstrate that acute acidic stress treatment of dermal fibroblast cultures greatly improves SKP isolation, growth, yield and multipotency compared to previous methods.