The Effect of Lipid Extract of Nannochloropsis oceanica Marine Microalgae on Glutathione and Thioredoxin-Dependent Antioxidant Systems in UVB-Irradiated Keratinocytes

UVB radiation present in sunlight is the main pro-oxidative and pro-inflammatory factor that reaches human skin cells, including keratinocytes. Therefore, protective compounds eliminating the negative impact of UVB radiation are constantly being sought. This study aimed to estimate the effect of the lipid extract of microalgae <i>Nannochloropsis oceanica</i> (<i>N.o.</i>) on UVB-irradiated keratinocytes. A proteomic approach was used to estimate the proteomic profile of in vitro-treated keratinocytes. The results indicated 270 proteins had significantly altered expression in UVB-irradiated keratinocytes, while the treatment of cells with <i>N.o.</i> extract partially restored the levels of these proteins. Moreover, changes in protein structure resulting from the binding of glutathione (GSH) and thioredoxin (Trx) were also observed. Most of the GSH-modified proteins were involved in GSH or prostaglandin metabolism, while Trx-modified proteins were molecules related to Trx metabolism, as well as antioxidant and anti-inflammatory signaling. The treatment of cells with <i>N.o.</i> extract contributed to reversing the changes in the level of modification in individual proteins. It can be suggested that the lipid components of the microalgae <i>N.o.</i> extract protect keratinocytes against changes in metabolism induced by UVB radiation, modulating the antioxidant and pro-inflammatory responses of cells at the GSH and Trx-based signaling levels.