The Beneficial Effects of a N-(1-Carbamoyl-2-phenyl-ethyl) Butyramide on Human Keratinocytes

Background: The skin microbiota-derived metabolite butyrate plays a pivotal role in maintaining skin health. Unfortunately, unpleasant sensorial properties and unfavorable physicochemical properties strongly limit the butyrate use in dermatology clinical practice. This study investigates the effects of N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA), a butyric acid releaser with neutral sensorial properties on skin keratinocyte function. Methods: Immortalized human keratinocyte cell line (HaCaT cells) was treated with FBA at various concentrations (0.001-1 mM) and time points (6-48 h). Cellular proliferation was assessed using MTT assays, while barrier integrity was evaluated by measuring tight junction proteins (occludin and ZO-1). Oxidative stress was analyzed using ROS assays and Western blot for Nrf2 and NF-κB expression. Markers of differentiation and extracellular matrix proteins were measured via quantitative PCR and wound-healing capability was assessed using a scratch assay. Results: FBA significantly enhanced keratinocyte proliferation at an optimal concentration of 0.1 mM. Tight junction protein expression increased, indicating improved barrier function. FBA reduced oxidative stress by upregulating Nrf2 and suppressing NF-κB activity. It also promoted the expression of differentiation markers (e.g., keratin-1, filaggrin) and extracellular matrix proteins (e.g., collagen type I and elastin). Furthermore, FBA accelerated wound closure, demonstrating its efficacy in enhancing the mechanisms of skin repair. Conclusions: Our results demonstrate that FBA enhances human keratinocyte cell differentiation, proliferation, and skin repair while protecting against oxidative stress. Its potential in cosmetics lies in delivering butyric acid benefits without organoleptic limitations, with possible applications in several skin condition characterized by deficient butyrate production and inflammation, such as atopic dermatitis.