Lipidome of narrow-band ultraviolet B irradiated keratinocytes shows apoptotic hallmarks.
BACKGROUND
UV light triggers a variety of biological responses in irradiated keratinocytes that might be associated with global perturbation of their lipidome. However, lipids that are specifically affected and the exact molecular mechanisms involved remain poorly understood.


OBJECTIVE
To characterize time-dependent changes of the lipidome of cultured keratinocytes induced by narrow-band ultraviolet B (NB-UVB) irradiation.


METHODS
Immortalized human keratinocytes (HaCaT) were cultured under standard conditions, irradiated with NB-UVB light (311 nm) at 400 and 800 mJ/cm(2) and collected 1, 2, 3, 6, 12 and 24 h later for lipid extraction. Lipid extracts were separated on silica plates in chloroform/ethanol/water/triethylamine (35:40:9:35) and in n-hexane/ethylacetate (5:1) followed by quantitative shotgun lipidomics analysis.


RESULTS
Irradiation with 800 mJ/cm(2) of NB-UVB altered morphology and lipidome composition of HaCaT cells. Ceramide content increased two-fold 6- and 12-h postirradiation with 800 mJ/cm(2), followed by threefold increase in triacylglycerols (TAGs) that peaked at 24 h. In addition, we observed marked increase of various phosphatidylcholine and phosphatidylethanolamine ethers, whereas phosphatidylcholine-species with short-chain fatty acid moieties decreased. The abundance of other lipid species was altered to lesser extent or remained unchanged.


CONCLUSIONS
NB-UVB affected the cellular lipidome of keratinocytes in strictly apoptosis-specific manner.
Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Wroclaw, Poland. adi_medicalis@go2.pl
Adam
A
Reich
Dominik
D
Schwudke
Michael
M
Meurer
Bodo
B
Lehmann
Andrej
A
Shevchenko
D017209:Apoptosis / Q000528:radiation effects*; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects*; D050356:Lipid Metabolism / Q000528:radiation effects*; D010713:Phosphatidylcholines / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000378:metabolism; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
D002518:Ceramides; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D014280:Triglycerides; C483858:phosphatidylethanolamine