Upregulation of tight junction-related proteins by hyaluronic acid in human HaCaT keratinocytes

Hyaluronic acid (HA) is a natural polysaccharide widely used in dermatology; however, HA effects on the expression of proteins related to skin barrier function and their dependence on the HA molecular weight are still limited. In this study, we treated immortalized human keratinocytes with HA samples of low and high molecular weights (LMW-HA, <100 kDa and HMW-HA, >500 kDa, respectively) and analyzed the expression of tight junction-forming proteins. Both LMW-HA and HMW-HA significantly increased the expression of claudin-3 and claudin-4, whereas HMW-HA also upregulated junctional adhesion molecule JAM-1. These results indicate that HA could improve the skin barrier function by inducing the expression of tight junction-related genes in keratinocytes and that the effect could depend on the molecular weight of HA fragments.