Dermal Mesenchymal Stem Cells from Psoriatic Lesions Stimulate HaCaT Cell Proliferation, Differentiation, and Migration via Activating the PI3K/AKT Signaling Pathway.

ABSTRACT

BACKGROUND: Psoriasis is a chronic inflammatory skin disease characterized by excessive proliferation and abnormal differentiation of keratinocytes. Dermal mesenchymal stem cells (DMSCs) are not only involved in the regeneration of skin tissue, but also can regulate skin microenvironment by secreting cytokines. However, whether and how psoriatic DMSCs regulate proliferation and differentiation of keratinocytes remains unknown. OBJECTIVE: To study the effects of psoriatic DMSCs on the proliferation, differentiation, and migration of keratinocytes and the underlying mechanisms. METHODS: Following co-cultures of HaCaT cells with either psoriatic DMSCs (p-DMSCs) or DMSCs from normal volunteers (n-DMSCs), HaCaT cell proliferation was assessed using CCK-8 and EDU incorporation assay, while scratch assay and transwell assay were used to assess cell migration. qRT-PCR was used to determine expression levels of mRNA for cell proliferation (Ki-67) and differentiation (keratin 5, involucrin, and filaggrin). Western blot was used to measure expression levels of proteins associated with keratinocyte proliferation and differentiation in cultured HaCaT cells treated with or without PI3K inhibitor. ELISA assay was used to measure expression profile of stem cell factor (SCF), epidermal growth factor (EGF), and interleukin-11 (IL-11) within the co-culture supernatants. RESULTS: The results showed that p-DMSCs displayed a higher potency than n-DMSCs in stimulating proliferation, differentiation, and migration of HaCaT cells. Expression levels of PI3K and AKT proteins were markedly increased in HaCaT cells co-cultured with DMSCs versus HaCaT cell culture alone. Moreover, inhibition of the PI3K/AKT signaling pathway reversed the effect of p-DMSCs on proliferation, differentiation, and migration of HaCaT cells. Compared with n-DMSCs, the p-DMSCs showed increased secretion of IL-11, EGF, and SCF. CONCLUSION: p-DMSCs stimulate HaCaT cell proliferation, differentiation and migration via activating the PI3K/AKT signaling pathway, providing a new insight into the pathogenesis of psoriasis.