Evaluation of adhesion, proliferation, and differentiation of human adipose-derived stem cells on keratin

Controlled adhesion and continuous growth of human adipose stem cells (hASCs) on delivery carriers are critical to cell therapy and tissue engineering. Keratin, derived from human hair, can be manipulated as a desired configuration and serve as an extracellular matrix. However, the effects of keratin on stem cells have not been fully understood. In this study, keratin-coting substrates were prepared to demonstrate the modulations of keratin matrix to the adhesion, proliferation, and differentiation of hASCs. The present results showed that keratin-coating substrates promoted hASCs adhesion, proliferation, and viability relative to those of untreated polystyrene plates. Evaluations of lineage-specific genetic markers and proteins revealed that the adipogenic, osteogenic and chondrogenic differentiations of hASCs can be successfully induced, which suggested that the stemness of hASCs was maintained when cultured on keratin-coating substrates. Relative to untreated polystyrene plates, keratin-coating increased the mRNA levels of lipoprotein lipase (LPL), peroxisome proliferator-activated receptor gamma (PPAR- γ), and CCAAT-enhancer binding protein alpha (CEBP-α) to hASCs, which reveals an improvement in adipogenic differentiation. Likewise, keratin also upregulated osteogenic markers such as type I collagen, alpha 1 (COL1A1), runt-related transcription factor 2 (RUNX2), and vitamin D receptor (VDR) to hASCs. Similarly, the chondrogenic marker SRY-box 9 (SOX9) was improved to hASCs on keratin-coating. The combination of hASCs with keratin shall be promising in the application of tissue repair to regenerative medicine.