1-Ethyl-Beta-N-Acetylglucosaminide Increases Hyaluronan Production In Human Keratinocytes By Being Converted To N-Acetylglucosamine Via Beta-N-Acetylglucosaminidase-Dependent Manner

Regulation of hyaluronan (HA) is important for the maintenance of epidermal homeostasis. Here, we examined the mechanism by which 1-ethyl-beta-N-acetylglucosaminide (beta-NAG2), a newly developed N-acetylglucosamine (NAG) derivative, increases HA production in cultured human epidermal keratinocytes. When keratinocytes were treated with beta-NAG2, mRNA expression of HA synthase 3, which is responsible for HA production in human keratinocytes, was not influenced, but the intracellular level of UDP-NAG, a substrate used for HA synthesis, was increased. By using a synthetic substrate for beta-N-acetylglucosaminidase (beta-NAGase), keratinocytes were found to possess beta-NAGase activity, and treatment of o-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino N-phenyl carbamate (PUGNAc), an inhibitor of beta-NAGase, abolished the release of NAG from beta-NAG2 in keratinocytes. Furthermore, PUGNAc attenuated the beta-NAG2-induced intracellular UDP-NAG and HA production in keratinocytes. These results suggest that beta-NAG2 is converted to NAG by endogenous beta-NAGase in keratinocytes, and the resulting NAG is further metabolized to UDP-NAG and utilized for HA production.