Human urine-derived stem cells alleviate psoriasis by suppressing JAK2/STAT3 pathway-mediated macrophage polarization.

BACKGROUND: Psoriasis is a chronic skin disease featured with aberrant keratinocyte proliferation, inflammatory cell infiltration, and immune dysregulated. Although the imbalance of M1/M2 macrophage polarization is implicated in its pathogenesis, the underlying mechanisms remain unclear. Mesenchymal stem cells exhibited potent immunomodulatory properties, representing a promising therapeutic approach for psoriasis. This study aimed to explore the role and the underlying mechanism of human urine-derived stem cells (hUSCs) in mouse psoriatic models. METHODS: hUSCs were isolated from urine of heath volunteer and cultured in serum-free medium, and characterized by multiple approaches such as morphological analysis, biological markers examination, differentiation potentials and tumorigenicity assay. Histological analysis, immunofluorescence staining, ELISA, flow cytometry, antibody array, western blot and qRT-PCR analysis were used to assess the therapeutic effects and the underlying mechanism of hUSCs in imiquimod (IMQ)-induced mouse psoriasis models and multiple cell models. RESULTS: hUSCs had the potential for self-renewal and multipotent differentiation with low immunogenicity and lacking tumorigenicity both in vitro and in vivo. Our results showed that hUSCs significantly alleviated IMQ-induced psoriasis via their paracrine, evidenced by improving morphologies, inhibiting the infiltration of macrophages, reducing the releases of the pro-inflammatory cytokines. Mechanistically, we revealed that the protective effects of hUSCs on psoriasis were involved in suppressing M1 and promoting M2 macrophage polarization, and inhibiting NETs formation through inhibiting JAK2/STAT3 pathway. Finally, we further demonstrated that hUSCs-derived TGF-β1 selectively inhibited the JAK2/STAT3 pathway-mediated the polarization of M1 and M2 macrophages to alleviate psoriasis in mouse and cellular models. CONCLUSIONS: Our data demonstrated that hUSCs remarkably ameliorated psoriasis by suppressing M1 and promoting M2 macrophage polarization through they-derived TGF-β1 inhibiting the JAK2/STAT3 pathway. Our results have revealed the molecular mechanism of hUSCs in treating psoriasis, highlighting a safe and effective cellular treatment method for psoriasis.