Very long chain fatty acids activate NADPH oxidase in human dermal fibroblasts.
Very long chain fatty acids (VLCFAs) are exclusively oxidized in peroxisomes and their levels are significantly increased in tissues of patients with peroxisomal disorders. Although the biochemical indicators of peroxisomal dysfunction, such as elevated VLCFAs, are well known, the mechanisms of pathogenesis of peroxisomal diseases are unclear. In this study we have examined the effect of VLCFAs on NADPH oxidase (NOX), a complex enzyme system responsible for the production of superoxide anions, in order to understand the oxidative stress-mediated mechanisms involved in pathology of peroxisomal disorders. Varying concentrations (2.5 to 10 microg ml(-1)) of VLCFAs, lignoceric acid and cerotic acid, significantly (p < 0.001) increased the enzymic activity of NOX in cultures of human dermal fibroblasts. VLCFAs did not affect the expression of gp91phox or p22phox whereas the mRNA and protein levels of p47phox were significantly (two or three-fold) increased following treatment of fibroblasts with lignoceric acid or cerotic acid. VLCFAs also caused a significant (p < 0.01) increase in lipid peroxidation in dermal fibroblasts which could be markedly reversed by treatment with apocyanin (10 mM) or superoxide dismutase (SOD, 25 U ml(-1)). With these results, we report for the first time that VLCFAs enhance NOX activity and superoxide anion-mediated lipid peroxidation in cultured dermal fibroblasts. This study proposes a mechanism that may be taking place in vivo during peroxisomal dysfunction and that leads to oxidative stress-mediated pathogenesis.
Dhaunsi
Gursev S
GS
Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait. dhaunsig@hsc.kuniv.edu.kw
Kaur
Jaspal
J
Alsaeid
Khaled
K
Turner
Ronald B
RB
Bitar
Milad S
MS
D000098:Acetophenones / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D006801:Humans; D008315:Malondialdehyde / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism*; D019308:Palmitic Acid / Q000494:pharmacology; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D012867:Skin / Q000166:cytology*; D013329:Structure-Activity Relationship; D013482:Superoxide Dismutase / Q000494:pharmacology
D000098:Acetophenones; D004791:Enzyme Inhibitors; D005227:Fatty Acids; D012333:RNA, Messenger; D019308:Palmitic Acid; D008315:Malondialdehyde; C056165:acetovanillone; C017364:hexacosanoic acid; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; C010210:lignoceric acid