Antinociception by the anti‐oxidized phospholipid antibody E06

Abstract

These authors contributed equally. BACKGROUND AND PURPOSEROS and their downstream molecules such as oxidized phospholipids (OxPL) and 4-hydroxynonenal activate TRPA1 and TRPV1 (vanilloid 1) cation channels in vivo and in vitro shaping thermal and mechanical hypersensitivity in inflammatory pain. E06/T15 is a monoclonal autoantibody against oxidized phosphatidylcholine (OxPC) used in diagnostics in arteriosclerosis. Recently, we provided evidence that E06 also ameliorates inflammatory pain. Here, we studied E06 for local treatment against hypersensitivity evoked by endogenous and exogenous agonists of TRPA1 or TRPV1 channels. EXPERIMENTAL APPROACHWe utilized a combination of reflexive and complex behavioural pain measurements, live-cell calcium imaging and OxPC-binding assays. The lipid peroxidation metabolite 4-hydroxynonenal, hydrogen peroxide as a source of ROS, allyl isothiocyanate and capsaicin were used to activate their respective receptors. KEY RESULTSAll irritants induced thermal and mechanical hypersensitivity, spontaneous nocifensive and affective-motivational behaviour, as well as calcium influx in HEK TRPA1 -or HEK TRPV1 -cells and dorsal root ganglion neurons. E06 prevented prolonged mechanical hypersensitivity induced by all irritants except for H 2 O 2 . E06 did not alter immediate irritant-induced nocifensive or affective motivational behaviour. In vitro, E06 blocked only 4-hydroxynonenal-induced calcium influx although this compound did not bind to E06. After 1-3 h, all tested irritants elicited formation of OxPC in paw tissue. CONCLUSIONS AND IMPLICATIONSE06 ameliorates not only inflammatory pain but also prolonged hypersensitivity due to formation of OxPC. This supports the view that neutralizing certain OxPL as endogenous activators of TRPA1 or TRPV1 channels may be valuable for pain therapy. Abbreviations

D-4F, an ApoA-I mimetic peptide ameliorating TRPA1-mediated nocifensive behaviour in a model of neurogenic inflammation

“…One of the downstream products of lipid peroxidation is 4-HNE that itself induces the generation of E06reactive OxPLs after local paw injections. 12 The preincubation of D-4F with 4-HNE diminished the TRPA1 activation in accordance to the results obtained after H 2 O 2 stimulation. Similar to H 2 O 2 , 4-HNE is also known to interact with histidine, lysine and cysteine residues.…”

“…To maintain the comparability of our studies, the concentrations of capsaicin (1 mM), H 2 O 2 (10 mM), 4-HNE (30 mM), MO (10 mM), KCL (45 mM) as well as D-4F (1 and 10 mg/ml) used here matched those from our earlier studies. 5,12 As before D-4F, dissolved in calcium imaging buffer containing 134 mM NaCl, 6 mM KCl, 2 mM MgCl 2 , 1 mM CaCl 2 , 10 mM Hepes and 5 mM glucose (pH 7.4), was either pre-incubated for 30 min with the cells at 37 C, 5% CO 2 in the incubator or with the agonists at room temperature. Calcium imaging data were processed before the statistical analysis of the number of reacting cells and the area under curve (AUC).…”

Pain Control by Targeting Oxidized Phospholipids: Functions, Mechanisms, Perspectives

“…Research on inflammatory pain in the early years focused on stable biomolecules like prostaglandins and peptides/proteins such as cytokines which trigger the action potential firing of nociceptors ( 8 ). Recently, works by our group and others have identified OxPL as proalgesic compounds in preclinical pain models ( 10 , 11 , 14 , 15 ). Mechanistically, the highly reactive, transient, endogenous irritants directly activate ion channels on nociceptive C-fiber neurons.…”

“…OxPAPC as well as its corresponding metabolites excite nociceptors and pain behaviour in different models for inflammatory pain ( 10 , 11 , 14 , 15 , 28 , 29 ). Specific OxPAPC components such as PGPC and POVPC as well as the OxPL degradation product lysophosphatidylcholine (LPC) are increased in chloroform-based lipid extracts from inflamed tissue by MALDI-TOF ( 10 ).…”

“…Also, downstream, the stimulation of TRP channels with OxPAPC is sufficient to release calcitonin gene-related peptide (CGRP), a potent vasodilator and mediator of peripheral nociceptor sensitization. This indicates that OxPL are not only excitants, but also contribute indirectly to neurogenic inflammation ( 10 , 15 ).…”