Stress-induced generation of N-acylethanolamines in mouse epidermal JB6 P+cells

It has long been known that N-acylethanolamine phospholipids [N-acylphospha tidylethanolamine (N-acyl PE)] and N-acylethanolamines (NAEs) accumulate in mammalian tissues undergoing degenerative membrane changes associated with necrosis. Here we studied the effects of stress factors (UVB irradiation a nd serum deprivation) on the endogenous levels of N-acyl PE and NAE in mous e epidermal JB6 P+ cells. We found that 16:0, 18.0, 18: 1,n-9 and 18: 1,n - 7 are the predominant amide-linked fatty acids in both N-acyl PE and NAE in these cells. UVB irradiation and serum deprivation resulted in significant ly increased levels of N-acyl PE and NAE, especially 18:1,n-9 N-acyl PE and NAE. UVB challenge increased the cellular content of anandamide (20:4,n - 6 NAE), but this increase was the lowest of all NAEs measured. Serum depriv ation resulted in a decreased cellular anandamide level, as well as a decre ase in 20:4,n-6 N-acyl PE. Interestingly, the replacement of serum-free med ium with medium containing 5%, (v/v) fetal calf serum after 36 h of serum d eprivation restored N-acyl PE and NAE levels almost completely within 4-8 h . These data suggest the involvement of N-acyl PE and NAE in cellular respo nses to stress.