Topical application of berberine ameliorates imiquimod-induced psoriasis-like dermatitis in BALB/c mice via suppressing JAK1/STAT1 signaling pathway

Psoriasis is a common chronic inflammatory skin disease, which has seriously affected human health. Berberine is a plant alkaloid with significant anti-inflammatory effect. In this study, we aimed to determine whether topical application of berberine could ameliorate skin inflammation in psoriasis and explore the potential molecular mechanism. Imiquimod (IMQ)-induced psoriasis-like dermatitis in mice was firstly used to reveal the potential pathogenic mechanism. The transcriptome analysis showed that Janus kinase (JAK)-Signal transducer and activator of transcription (STAT) signaling pathway was significantly enriched in IMQ-induced dermatitis, which included the key genes such as Janus kinase 1 (JAK1), Interleukin-2 (IL2), Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA), Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit beta isoform (PIK3CB) and Signal transducer and activator of transcription 1 (STAT1). Network pharmacology and molecular docking then predicted that topical berberine may treat psoriasis by JAK-STAT signaling pathway, especially act on JAK1, IL2, PIK3CA and PIK3CB. Experimental studies in vivo further demonstrated that topical application of berberine could ameliorate IMQ-induced psoriasis-like skin inflammation by suppressing JAK-STAT signaling pathway. In addition, experimental studies in vitro showed that berberine could directly act on and enter into human immortalized keratinocytes (HaCaT cells). Meanwhile, berberine may inhibit the hyperproliferation and proinflammatory functions of HaCaT cells induced by Interferon-gamma (IFN-γ) via suppressing JAK1/STAT1 signaling pathway. In conclusion, this study suggested that berberine may be a promising topical agent to ameliorate skin inflammation in psoriasis.