Lipidomic assessment of the impact of Nannochloropsis oceanica microalga lipid extract on human skin keratinocytes exposed to chronic UVB radiation

Considerable attention has been devoted to investigating the biological activity of microalgal extracts, highlighting their capacity to modulate cellular metabolism. This study aimed to assess the impact of Nannochloropsis oceanica lipid extract on the phospholipid profile of human keratinocytes subjected to UVB radiation. The outcomes revealed that treatment of keratinocytes with the lipid extract from microalgae led to a reduction in sphingomyelin (SM) levels, with a more pronounced effect observed in UVB-irradiated cells. Concomitantly, there was a significant upregulation of ceramides CER[NDS] and CER[NS], along with increased sphingomyelinase activity. Pathway analysis further confirmed that SM metabolism was the most significantly affected pathway in both non-irradiated and UVB-irradiated keratinocytes treated with the microalgal lipid extract. Additionally, the elevation in alkylacylPE (PEo) and diacylPE (PE) species content observed in UVB-irradiated keratinocytes following treatment with the microalgal extract suggested the potential induction of pro-survival mechanisms through autophagy in these cells. Conversely, a noteworthy reduction in LPC content in UVB-irradiated keratinocytes treated with the extract, indicated the anti-inflammatory properties of the lipid extract obtained from microalgae. However, to fully comprehend the observed alterations in the phospholipid profile of UVB-irradiated keratinocytes, further investigations are warranted to identify the specific fraction of compounds responsible for the activity of the Nannochloropsis oceanica extract.