The molecular mechanism of berberine affecting psoriasis skin inflammation by regulating keratinocyte pyroptosis via the p38 MAPK/NF-κB pathway.

Berberine (BBR), a Rhizoma Coptis-sourced isoquinoline alkaloid, is an effective drug for psoriasis treatment with its therapeutic mechanism remaining unclear. We delved into the mechanism of BBR affecting psoriatic skin inflammation by regulating keratinocyte pyroptosis. A psoriasis-like skin inflammation mouse model was induced by imiquimod (IMQ) and treated with BBR and a p38 activator anisomycin. Human epidermal keratinocytes (HEKs) were stimulated with five chemokines (M5) [interleukin (IL)-17A, IL-22A, oncostatin M, tumor necrosis factor-α, IL-1α] to simulate psoriasis immune microenvironment, then treated with BBR and anisomycin. Psoriasis skin lesions, skin tissue damage, cell viability and death, and gasdermin D-N (GSDMD-N) and NOD-like receptor protein 3 (NLRP3) positive cell numbers were assessed. The p38 mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) pathway and levels of the NLRP3/GSDMD pathway-related proteins and inflammatory factors were determined. BBR alleviated M5-induced HEK pyroptosis by inactivating NLRP3 inflammasomes. BBR inhibited the p38 MAPK/NF-κB pathway, and its effects on HEKs were partly averted by activating the p38 MAPK/NF-κB pathway. BBR repressed NLRP3 inflammasome activation and pyroptosis by inhibiting the p38 MAPK/NF-κB pathway. Collectively, BBR suppressed keratinocyte NLRP3/GSDMD pathway pyroptosis by suppressing the p38 MAPK/NF-κB pathway, thereby affecting psoriasis skin inflammation.