Lactobacillus brevis-Derived Exosomes Enhance Skin Barrier Integrity by Upregulating Key Barrier-Related Proteins.

INTRODUCTION: The human skin, comprising the epidermis, dermis, and subcutaneous fat layers, serves as a critical barrier against external stimuli. The integrity of this barrier function is essential for preventing skin damage and diseases. When compromised, it can lead to various dermatological issues. METHODS: This study investigated the efficacy of Lactobacillus brevis J2K55-derived exosomes (LBDEs) on enhancing skin barrier function. High-purity LBDEs were produced and characterized using nanoparticle tracking analysis and Cryo-TEM, concentrated to 1.52×10(8) particles/mL with sizes ranging from 50 to 200 nm. The LBDEs were then applied to human keratinocytes, HaCaT cells, and a live human skin model to analyze the expression of genes significant to skin barrier function. RESULTS: In vitro experiments demonstrated that 2.5% LBDEs increased Filaggrin mRNA expression by 301.80% compared to the control. In an ex vivo skin damage model induced by physical stimulation and UVB (Ultraviolet B) irradiation, 1% LBDEs treatment significantly upregulated the expression of key barrier-related proteins, including Aquaporin-3 (180.8%), Claudin-1 (205.4%), Filaggrin (309.9%), Loricrin (365.2%), and Serine palmitoyltransferase (191.3%), in comparison to the friction and UVB-induced control group. CONCLUSION: These results suggest that LBDEs have potential in enhancing skin barrier function, as evidenced by increased expression of crucial barrier-related proteins in both in vitro and ex vivo models.