Novel Compounds That Interact with Both Leukotriene B₄ Receptors and Vanilloid TRPV1 Receptors

Abstract

The aim of this study was to investigate the interaction of a series of novel compounds with leukotriene B 4 receptors (BLT) and vanilloid receptor (TRPV1). First, we characterized leukotriene B 4 (LTB 4 ) ethanolamide. In guinea pig isolated lung parenchyma, LTB 4 ethanolamide antagonized the contractile action of LTB 4 with an apparent K B value of 7.28 nM. Using a Boyden chamber assay, we demonstrated that this compound stimulated human neutrophil migration in a similar manner to LTB 4 but with lower efficacy. In rat TRPV1 (rTRPV1)-expressing Chinese hamster ovary (CHO) cells and dorsal root ganglion (DRG) neurons, LTB 4 and LTB 4 ethanolamide acted as low-efficacy agonists, increasing intracellular calcium concentration ([Ca 2ϩ ] i ) in a capsazepine-sensitive manner. These results prompted us to hypothesize that a molecule may possess pharmacophores such that it is capable of dual antagonism of BLT and TRPV1 receptors. Two novel compounds, In rTRPV1-expressing CHO cells, they caused a significant rightward shift in the log concentration-response curve for the TRPV1 receptor agonist capsaicin (3-methoxy-4-hydroxy)benzyl-8-methyl-6-nonenamide). In DRG neurons O-3367 significantly attenuated the capsaicin-induced increases in [Ca 2ϩ ] i with a pIC 50 value of 5.94 Ϯ 0.004. O-3367 and O-3383 represent novel structural templates for generating compounds possessing dual antagonism at BLT and TRPV1 receptors. In view of the crucial role of both TRPV1 and BLT receptors in the pathophysiology of inflammatory conditions, such compounds may betoken a novel class of highly effective therapeutics.Leukotriene B 4 (LTB 4 ) is a potent proinflammatory agent. It has an important role in a number of processes, including neutrophil activation and degranulation, leukocyte migration into the bloodstream, inflammatory pain, and host defense against infection. LTB 4 has been implicated in the pathophysiology of various diseases, including psoriasis, inflammatory bowel disease, arthritis, and asthma (FordHutchison, 1990). In 1997, Yokomizo et al. cloned an LTB 4 G protein coupled receptor (BLT1). This is a high-affinity specific receptor for LTB 4 found predominantly in peripheral leukocytes, with lower expression also found in lung and spleen (Yokomizo et al., 2000a). More recently, a second low-affinity LTB 4 receptor (BLT2) has been cloned (Kamohara et al., 2000;Yokomizo et al., 2000b). The BLT2 receptor seems to be ubiquitously expressed with highest levels in spleen then liver, ovary, and leukocytes (Yokomizo et al., 2000a). The interaction of LTB 4 at these receptors is a contributing factor in the pathogenesis of inflammatory disease (Tager and Luster, 2003). Studies involving the targeted deletion of murine BLT1 and the effect of antagonizing LTB 4 This work was supported by grants from Allergan Inc. (Irvine, CA) (to R.A.R. and D.M.) and National Institutes of Health (to R.R., R.G.P., and R.A.R.).Article, publication date, and citation information can be found at http://jpet.aspetjournals.org. doi:10.1124/jp...

International Union of Basic and Clinical Pharmacology. LXXXIV: Leukotriene Receptor Nomenclature, Distribution, and Pathophysiological Functions

“…The EC 50 for LTB 4 -induced TRPV1 activation was 11 M, which was 10-fold higher than that obtained for capsaicin in the latter study (Hwang et al, 2000) and substantially lower compared with BLT 1 R-mediated LTB 4 -induced signaling. In line with these findings, LTB 4 also increased [Ca 2ϩ ] i in TRPV1-transfected CHO cells, albeit with significantly lower E max and a longer exposure time required to achieve maximum effects compared with capsaicin (McHugh et al, 2006). Indeed, very recently it has also been demonstrated in vivo that both peripheral and spinal administration of RvE1 or RvD1 in mice potently reduces inflammatory pain behaviors, without affecting basal pain perception.…”

“…The TRPV1 receptor is a ligand-gated, nonselective cation channel, which belongs to a family of TRP channels present exclusively in small sensory neurons and associated with pain. Although capsaicin and other vanilloids are the classic agonists, endogenous ligands derived from lipoxygenase metabolism of arachidonic acid and anandamide have also been reported to activate TRPV1 receptors (Hwang et al, 2000;McHugh et al, 2006). In inside-out patches of cultured dorsal root ganglion, TRPV1 receptors are activated by lipoxygenase products such as 12(S)-HpETE, 15(S)-HpETE, 5(S)-HETE, and LTB 4 , whereas LTC 4 is without effect (Hwang et al, 2000).…”

Opportunistic activation of TRP receptors by endogenous lipids: Exploiting lipidomics to understand TRP receptor cellular communication

“…Other identified endogenous activators for TRPV1 are lipoxygenase products of arachidonic acid (e.g. 12-(s)-HPETE, 9-HODE) (Hwang et al , 2000, Patwardhan et al , 2009), LTB4 (McHugh et al , 2006) and N -(4-hydroxyphenyl) arachidonoylethanolamide (AM404), which is a metabolite of paracetamol (De Petrocellis et al , 2000). Each of these lipids, likewise are small molecular weight lipids that share a general structural homology in being derived directly from a single fatty acid chain or fatty acid amide that is oxygenated.…”

TRPV1: On the Road to Pain Relief

“…Other molecules, such as nerve growth factor (NGF), protons, ATP, histamine, cytokines and chemokines act as proalgesic, proinflammatory mediators [165, 166]. In addition, TRPV1 is also modulated by leukotriene B4 (LTB4) and other metabolites of arachidonic acid, and this contributes to the development of neurogenic inflammation [167]. To this point, following injury, increased TRPV1-immunoreactive fiber innervation has been observed in inflamed tissues such as: gastrointestinal tract, human skin and vulva [161, 168–172].…”