Curcumin-Loaded Nanospheres Attenuate Fine Dust (PM10)-Induced Cellular Toxicity by Suppressing Reactive Oxygen Species-Dependent Signaling in Human Keratinocytes.

Curcumin has various biological effects, but its poor aqueous solubility limits its practical use. This study investigated the effects of curcumin-loaded nanospheres (CN) on cellular injury induced by fine dust (PM10) in HaCaT human keratinocytes and examined the signaling mechanisms involved. PM10 exposure significantly decreased cell viability, whereas CN at 10-4 μg/mL significantly restored cell viability and showed a protective effect at a lower concentration than unformulated curcumin. PM10 rapidly increased intracellular reactive oxygen species (ROS) levels, followed by activation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and nuclear factor-kappa B (NF-κB). CN reduced ROS generation and inhibited activation of these signaling molecules. CN also restored the altered Bax/Bcl-2 balance, decreased caspase-3 cleavage, and reduced caspase-1-dependent IL-1β processing in PM10-exposed cells. Treatment with NAC and inhibitors of ERK, p38 MAPK, NF-κB, and caspase-1 further reduced PM10-induced cytotoxic and inflammatory responses, supporting the involvement of these pathways. Overall, CN attenuated fine dust-induced cellular toxicity in keratinocytes by suppressing ROS-dependent MAPK/NF-κB signaling and downstream apoptotic and inflammatory responses.