Lipidomes of brain from rats acutely intoxicated with diisopropylfluorophosphate identifies potential therapeutic targets

Abstract

Organophosphates (OPs), a class of phosphorus-containing chemicals that act by disrupting cholinergic transmission, include both toxic and fast-acting chemical warfare agents as well as less toxic but more easily accessible OP pesticides. The classical atropine/2-PAM antidote fails to protect against long-term symptoms following acute intoxication with OPs at levels that trigger status epilepticus. Acute OP intoxication also causes a robust neuroinflammatory response, which is implicated in the pathogenesis of long-term effects. In this study, we characterized the profiles of lipid mediators, important players in neuroinflammation, in the rat model of acute DFP intoxication. The profiles of lipid mediators were monitored in three different regions of the brain (cortex, hippocampus, and cerebellum) at 0, 1, 3, 7, 14, and 28 days post-exposure. The distribution pattern of lipid mediators was distinct in the three brain regions. In the cerebellum, the profile is dominated by LOX metabolites, while the lipid mediator profiles in cortex and hippocampus are dominated by COX metabolites followed by LOX and CYP 450 metabolites. Following acute DFP intoxication, most of the pro-inflammatory lipid mediators (e.g., PGD2 and PGE2) increased rapidly from day 1, while the concentrations of some anti-inflammatory lipid mediators (e.g. 14,15 EpETrE) decreased after DFP intoxication but recovered by day 14 postexposure. The lipidomics results suggest two potential treatment targets: blocking the formation of prostaglandins by inhibiting COX and stabilizing the anti-inflammatory lipid mediators containing epoxides by inhibiting the enzyme soluble epoxide hydrolase (sEH).

Ibuprofen alters epoxide hydrolase activity and epoxy-oxylipin metabolites associated with different metabolic pathways in murine livers

“…Extraction and analyses of the regulatory lipid mediator: The extraction process is similar to the protocol as described in a previously published paper 28 . 10 µL of methanol containing deuterated internal standard solution, a mixture of d4 PGF1α, d4 TXB2, d4 PGE2, d4 LTB4, d11 14,15 DiHETrE, d6 20 HETE, d4 9 HODE, d8 5 HETE, d11 11,12 EpETrE (Cayman Chemical, Ann Arbor, MI), was added to approximately 100 mg of liver tissue.…”

“…In brief, separation was achieved on an Agilent Eclipse Plus C18 150 × 2.1 mm 1.8 um column with mobile phases of water with 0.1% acetic acid as mobile phase A and acetonitrile/methanol (84/16) with 0.1% acetic acid as mobile phase B. All the parameters on the mass spectrometer were optimized with pure standards (purchased from Cayman Chemical, Ann Arbor, MI) under negative mode 28 , 29 . A scheduled multiple reaction monitoring (MRM) scan mode was employed to increase the sensitivity of the measurement.…”

Ibuprofen alters epoxide hydrolase activity and epoxy-oxylipin metabolites associated with different metabolic pathways in murine livers

“…In brief, separation was achieved on an Agilent Eclipse Plus C18 150 × 2.1 mm 1.8 um column with mobile phases of water with 0.1% of acetic acid as mobile phase A and acetonitrile/methanol (84/16) with 0.1% of acetic acid as mobile phase B. All the parameters on the mass spectrometer were optimized with pure standards (purchased from Cayman Chemical, Ann Arbor, MI) under negative mode 28,29 . A scheduled multiple reaction monitoring (MRM) scan mode was employed to increase the sensitivity of the measurement.…”

“…Extraction and analyses of the regulatory lipid mediator: The extraction process is similar to the protocol as described in a previously published paper 28 . 10 µL of methyl acetate containing deuterated internal standard solution, a mixture of d4 PGF1, d4 TXB2, d4 PGE2, d4 LTB4, d11…”

“…Although 70 oxylipins were detected, many more oxylipins are known, as well as other oxylipins for which standards are unavailable of oxylipins that are currently undiscovered. Also although we are using state of the art lipidomic techniques 28,29 all lipidomic techniques utilize extraction methods that favor some types of oxylipins over others 92 . Hence, it is not possible to conclude that more oxylipins from CYP pathways are altered than oxylipins from the COX pathways.…”