Paenibacillus exopolysaccharide alleviates Malassezia-induced skin damage: Enhancing skin barrier function, regulating immune responses, and modulating microbiota.

Numerous studies have established a strong association between Malassezia and various skin disorders, including atopic dermatitis. Finding appropriate methods or medications to alleviate Malassezia-induced skin damage is of notable public interest. This study aimed to evaluate the therapeutic effect of the exopolysaccharide EPS1, produced by Paenibacillus polymyxa, on Malassezia restricta-induced skin damage. In vitro assays indicated that EPS1 reduced the expression of pro-inflammatory cytokine genes in TNF-α-induced HaCaT cells. In a murine model, EPS1 was found to mitigate clinical symptoms, reduce epidermal thickness and mast cell infiltration, improve skin barrier function, decrease pro-inflammatory cytokine levels associated with type 17 inflammation, enhance Tregs in the spleen, upregulate the transcription of Treg-related genes in skin lesions, and modulate the skin microbiota. This study is the first to report the alleviating effect of Paenibacillus exopolysaccharide on Malassezia-induced skin inflammation and its impact on the skin microbiota. These findings support the potential of Paenibacillus exopolysaccharides as consumer products and therapeutic agents for managing Malassezia-induced skin damage by improving skin barrier function, modulating immune responses, and influencing skin microbiota.