Posttranslational modifications of CYP4F11 by 4-hydroxynonenal inhibit enzyme ω-hydroxylation function: putative role in malaria immunosuppression

Malaria is still the most important parasitic infection disease in the world. Monocytes play a crucial role in the first line defence against malaria and are the precursors of professional antigen presenting cells as macrophages and dendritic cells which links them to adaptive immunity. Human monocyte functions are changed by phagocytosis of the i) parasite biocrystal hemozoin (HZ), ii) HZ containing mature forms of Plasmodium. HZ shuttles bioactive lipid products, as 4-hydroxynonenal (4-HNE), hydroxyeicosatetraenoic acids (HETEs) and hydroxyoctadecadienoic acids (HODEs), considered as “inhibitory” molecules for cellular processes. CYP4 enzymes are involved in degradation of HETEs, but the modifications of CYP4 enzymes under pathological conditions and connection with human immune response is not described. In this work we study the modifications and malfunction of CYP4F11 enzyme elicited by lipoperoxidation product 4-HNE abundant in malaria patients and suggested to be involved in immune suppression. The CYP4F11 is produced in its recombinant form by E.coli DH5α, purified and used for catalytic reactions with selected fatty acids. The spectrometry-based subtract binding studies and NADPH consumption assay show the ability of CYP4F11 to react with palmitic and arachidonic acid, and gas chromatography shows the hydroxylated products. 4-HNE is able to modify CYP4F11 by adducts creation confirmed by Western blotting and MALDI-TOF analysis. The functionality of modified enzyme becomes inhibited: substrate binding and NADPH consumption are failed for palmitic and arachidonic acids. Obtained results suggest the new mechanism of immune imbalance in malaria based on suppression of CYP4F11 detoxification function.