Free radical- and ROS-mediated lipid peroxidation of AA forms mixed hydroperoxy eicosatetraeneoic acids (HpETE) positional isomers (including 5-, 8-, 11-, 12-, or 15 HpETE).
Note: AA, arachidonic acid; COX, cyclooxygenase; EPA, eicosapentaenoate; GPx, glutathione peroxidase; GSH, glutathione; HETE, Hydroxyeicosatetraenoic acid; HODE, Hydroxyoctadecadienoic acid; HpEPE, hydroperoxy5Z,8Z,11Z,13E,17Z-eicosapentaenoic acid; HpETE, hydroperoxyeicosatetraenoic acid; HpODE, hydroperoxy-9Z,11E-octadecadienoic acid; LA, linoleic acid; LOX, lipoxygenase; NOx, Nitrogen oxides; O3, Ozone; OS, oxidative stress; PGH2, prostaglandins; PLA2, phospholipases A2; PM, particulate matter; SAH, S-adenosylhomocysteine.
The OSCC cell line has been observed with increased expression of Transient Receptor Potencial Vanilloid (TRPV1), which is activated by HPETE
(a product of ALOX12B-mediated reactions).
These findings were supported by cell-based experiments showing that treating GPX[4.sup.-/-] cells with HpETE
led to significantly accelerated loss of cell viability whereas the addition of HETE had no impact on cell death .
The products of LOXs catalysed oxygenation (hydroperoxyeicosatetraenoic acids; HPETE
hydroxyleicosatetraenoic acids; HETE) leukotrienes and lipoxins) are actually involved in the development of different disorders such as rheumatoid arthritis psoriasis asthmatic responses and glomerular nephritis.
In humans, the term 12/15-LOX refers to leukocyte-type 12-LOX and-reticulocyte-type 15-LOX-1 since they produce the similar lipid mediators such as 12-and 15-hydroperoxyeicosatetraenoic acids (HPETEs
) and hydroxyeicosatetraenoic acids (HETEs).
CYP can produce epoxy-modified arachidonic acids (EETs) and hydroxy-modified arachidonic acids (HETEs), while COX can produce prostaglandins and thromboxanes, and LOX can produce leukotrienes and hydroperoxides (HPETEs
The main enzymes that generate lipid signaling mediators are lipoxygenase, which mediate hydroperoxyeicosatetraenoic acids (HPETEs
), lipoxins, leukotrienes, or hepoxilins biosynthesis after oxidation of arachidonic acid (AA) [4, 5], cyclooxygenase that produces prostaglandins , and cytochrome P-450 (CYP) which generates epoxyeicosatrienoic acids, leukotoxins, thromboxane, or prostacyclin .
Flavocoxid was incubated along with purified 5-LOX enzyme in the presence of an oxygen sensing chromagen in vitro to study the formation of unstable hydroperoxyeicosatetraenoic acids (HPETEs
) intermediates in the synthesis of LTs.