The effects of human dermal-derived mesenchymal stem cells on the keratinocyte proliferation and apoptosis in psoriasis.

Psoriasis is a common chronic inflammatory skin disease, characterized by epidermal hyperproliferation. Mesenchymal stem cells (MSCs) regulate inflammation and vascular proliferation in the psoriasis lesions. Whether dermal-derived mesenchymal stem cells (DMSCs), the main MSCs in the dermis, regulate keratinocyte proliferation and apoptosis remains unknown. In the present study, we assessed the proliferation and apoptosis of keratinocytes cocultured with DMSCs isolated from either normal or psoriatic involved skin. Cell growth and apoptotic rates were determined using Cell Count Kit-8 and annexin V-FITC staining, respectively. In addition, EDU kit was also used to measure the rate of keratinocyte proliferation. Our results showed that psoriatic DMSCs (pDMSCs) were more potent than normal DMSCs (nDMSCs) in stimulating keratinocyte proliferation. In contrast, the apoptotic rate and expression levels of caspase-3 protein were lower in pDMSC-treated than nDMSC-treated keratinocytes (p < 0.001). Moreover, significantly higher contents of IL-6, IL-8, TNF-α and IFN-γ were found in the culture medium of pDMSCs than in that of nDMSCs. In conclusion, pDMSCs were more potent than nDMSCs in stimulation of keratinocyte proliferation and secretion of proinflammatory cytokines, but weaker in promoting apoptosis.