CYP-13A12 of the nematode C. elegans is a PUFA-epoxygenase involved in behavioural response to reoxygenation

A specific behavioural response of Caenorhabditis elegans, the rapid increase of locomotion in response to anoxia/reoxygenation called the O2-ON response, has been used to model key aspects of ischemia/reperfusion injury. A genetic suppressor screen demonstrated a direct causal role of CYP-13A12 in this response and suggested that CYP-eicosanoids, which in mammals influence the contractility of cardiomyocytes and vascular smooth muscle cells, might function in C. elegans as specific regulators of the body muscle cell activity. Here we show that co-expression of CYP-13A12 with the NADPH-CYP-reductase EMB-8 in insect cells resulted in the reconstitution of an active microsomal monooxygenase system that metabolised EPA (eicosapentaenoic acid) and also AA (arachidonic acid) to specific sets of regioisomeric epoxy and hydroxy derivatives. Main products included 17,18-EEQ (epoxyeicosatetraenoic acid) from EPA and 14,15-EET (epoxyeicosatrienoic acid) from AA. Locomotion assays showed that the defective O2-ON response of C20-PUFA-deficient, Δ-12 and Δ-6 fatty acid desaturase mutants (fat-2 and fat-3, respectively) can be restored by feeding the nematodes AA or EPA, but not ETYA (eicosatetraynoic acid), a non-metabolisable AA-analogue. Already short-term incubation with 17,18-EEQ was sufficient to rescue the impaired locomotion of the fat-3 strain. The endogenous level of free 17,18-EEQ declined during anoxia and was rapidly restored in response to reoxygenation. Based o...
Source: BJ Signal - Category: Biochemistry Authors: Tags: BJ Signal Source Type: research