Activation of NLRP3 Inflammasome by Palmitic Acid in Human Sebocytes

BACKGROUND: Sebocytes are the main cells involved in the pathogenesis of acne by producing lipids and inflammatory cytokines. Although palmitic acid (PA) has been suggested to induce an inflammatory reaction, its effect on sebocytes remains to be elucidated. OBJECTIVE: In the present study, we investigated whether PA promotes inflammasome-mediated inflammation of sebocytes both in vivo and in vitro. METHODS: We intradermally injected PA into the mice ears. And, we treated cultured human sebocytes with PA. Inflammasome-mediated inflammation was verified by immunohistochemistry, Western blot and ELISA. RESULTS: PA-treated mice developed an inflammatory response associated with increased interleukin (IL)-1β expression in the sebaceous glands. When PA was added to cultured human sebocytes, caspase-1 activation and IL-1β secretion were significantly enhanced. In addition, NLRP3 knockdown attenuated IL-1β production by sebocytes stimulated with PA. PA-mediated inflammasome activation required reactive oxygen species. CONCLUSION: These findings indicate that PA activates the NLRP3 inflammasome before induction of an inflammatory response in sebocytes. Thus, PA may play a role in the inflammation of acne.