Identification of 9-Hydroxyoctadecadienoic Acid and Other Oxidized Free Fatty Acids as Ligands of the G Protein-coupled Receptor G2A

Obinata, Hideru; Hattori, Tomoyasu; Nakane, Shinji; Tatei, Kazuaki; Izumi, Tohru

doi:10.1074/jbc.m507787200

Cited by 157 publications

(151 citation statements)

References 42 publications

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“…In contrast, the linoleic acid metabolites are well recognized to be involved in numerous neurological and non-neurological disorders (9,(24)(25)(26)(27)(28). The known receptors for these metabolites cannot explain all of their observed effects (29)(30). Similarly, the activity of TRPV1 in the CNS is linked with many other disorders apart from pain (31).…”

Section: Discussionmentioning

confidence: 99%

Activation of TRPV1 in the spinal cord by oxidized linoleic acid metabolites contributes to inflammatory hyperalgesia

Patwardhan¹,

Scotland

Akopian³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

198

191

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Transient receptor potential vanilloid 1 (TRPV1) plays a major role in hyperalgesia and allodynia and is expressed both in the peripheral and central nervous systems (CNS). However, few studies have evaluated mechanisms by which CNS TRPV1 mediates hyperalgesia and allodynia after injury. We hypothesized that activation of spinal cord systems releases endogenous TRPV1 agonists that evoke the development of mechanical allodynia by this receptor. Using in vitro superfusion, the depolarization of spinal cord triggered the release of oxidized linoleic acid metabolites, such as 9-hydroxyoctadecadienoic acid (9-HODE) that potently activated spinal TRPV1, leading to the development of mechanical allodynia. Subsequent calcium imaging and electrophysiology studies demonstrated that synthetic oxidized linoleic acid metabolites, including 9-HODE, 13-HODE, and 9 and 13-oxoODE, comprise a family of endogenous TRPV1 agonists. In vivo studies demonstrated that intrathecal application of these oxidized linoleic acid metabolites rapidly evokes mechanical allodynia. Finally, intrathecal neutralization of 9-and 13-HODE by antibodies blocks CFA-evoked mechanical allodynia. These data collectively reveal a mechanism by which an endogenous family of lipids activates TRPV1 in the spinal cord, leading to the development of inflammatory hyperalgesia. These findings may integrate many pain disorders and provide an approach for developing analgesic drugs.inflammation ͉ pain T ransient receptor potential vanilloid 1 (TRPV1) plays a pivotal role in many pain models, leading to the development of hyperalgesia and/or allodynia (1-2). TRPV1 is expressed in the peripheral as well as central nervous systems (CNS) including several areas involved in nociceptive transmission (3). Numerous studies have demonstrated that peripheral TRPV1 is activated by noxious heat and protons and is regulated by endogenous ligands (2), contributing to peripheral mechanisms of heat hyperalgesia (4). However, TRPV1 is also expressed in the CNS, where comparatively little is known about the role of this receptor in mediating central pain mechanisms.Recent studies have used TRPV1 antagonists to evaluate the role of CNS TRPV1 in inflammatory hyperalgesia. Interestingly, the systemic/spinal administration of TRPV1 antagonists blocks inflammation-induced heat hyperalgesia, as well as mechanical allodynia (5-6). These findings were unexpected since TRPV1 is not activated by mechanical stimuli, suggesting that spinal TRPV1 activation leads to central sensitization to both thermal and mechanical stimuli (7-8). Based upon these observations, we hypothesized that the afferent barrage resulting from peripheral tissue injury leads to generation of endogenous TRPV1 ligands in the spinal cord that activate TRPV1 in the CNS resulting in central sensitization. Results Depolarization of Spinal Cord Results in the Release of EndogenousTRPV1 Ligands. To evaluate the hypothesis that endogenous TRPV1 agonists are released from spinal cord neurons, freshly isolated male rat spinal cords w...

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Section: Discussionmentioning

confidence: 99%

Activation of TRPV1 in the spinal cord by oxidized linoleic acid metabolites contributes to inflammatory hyperalgesia

Patwardhan¹,

Scotland

Akopian³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

198

191

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“…29 Furthermore, G2A receptor signaling may also depend on other oxidized fatty acids 30 for specific interactions with intracellular G-proteins and GPCRs. 31 Thus, the effects of LPC or other lysophospholipids on migration may depend on the specific phagocyte, owing to differential expression of GPCRs and G-proteins in different cell types.…”

Section: Steps Involved In Clearancementioning

confidence: 99%

Do not let death do us part: ‘find-me’ signals in communication between dying cells and the phagocytes

2016

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The turnover and clearance of cells is an essential process that is part of many physiological and pathological processes. Improper or deficient clearance of apoptotic cells can lead to excessive inflammation and autoimmune disease. The steps involved in cell clearance include: migration of the phagocyte toward the proximity of the dying cells, specific recognition and internalization of the dying cell, and degradation of the corpse. The ability of phagocytes to recognize and react to dying cells to perform efficient and immunologically silent engulfment has been well-characterized in vitro and in vivo. However, how apoptotic cells themselves initiate the corpse removal and also influence the cells within the neighboring environment during clearance was less understood. Recent exciting observations suggest that apoptotic cells can attract phagocytes through the regulated release of 'find-me' signals. More recent studies also suggest that these find-me signals can have additional roles outside of phagocyte attraction to help orchestrate engulfment. This review will discuss our current understanding of the different find-me signals released by apoptotic cells, how they may be relevant in vivo, and their additional roles in facilitating engulfment.

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“…Although lyso-PC was originally thought to be a ligand of the G2A receptor (10), more recent data suggest that rather than acting directly as a ligand, lyso-PC alters receptor G2A distribution and signaling by preventing its reuptake or altering its residency on the cell surface (11,12). Of note, oxidized unsaturated fatty acids have also enhanced calcium flux in Chinese hamster ovary cells mediated via G2A (13). These data, along with various reports of lyso-PLs bearing other head groups having biological effects on other cells including neutrophils (1, 8, 14 -16), raised the question as to whether they too might signal similarly to neutrophils through G2A.…”

Section: Lysophospholipids Of Different Classes Mobilize Neutrophilmentioning

confidence: 99%

“…Given the prominence of GPCR3 G␣ i 3 PLC signaling in neutrophils, this pathway was studied first. As precedent, lyso-PC stimulation has been associated with G2A signaling through G␣ i to PLC in various cell types (3-5, 24), although not others, where G2A signaling through other G␣ subunits has been demonstrated (e.g., G␣ 13 and G␣ q ) (38 -41). Similarly, lyso-PS induced calcium flux in leukemic cells in a manner inhibited by pertussis toxin (whereas murine fibroblasts were insensitive) and by the PLC inhibitor, U-73122 (42,43).…”

Section: C18:1/oh Lyso-pls Signals Via G2a To G␣ I and Plcmentioning

confidence: 99%

Lysophospholipids of Different Classes Mobilize Neutrophil Secretory Vesicles and Induce Redundant Signaling through G2A

Frasch

Berry²,

Murphy³

et al. 2007

The Journal of Immunology

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Lysophosphatidylcholine has been shown to enhance neutrophil functions through a mechanism involving the G protein-coupled receptor G2A. Recent data support an indirect effect of lysophosphatidylcholine on G2A rather than direct ligand binding. These observations prompted the hypothesis that other lysophospholipids (lyso-PLs) may also signal for human neutrophil activation through G2A. To this end, 1-oleoyl-2-hydroxy-sn-glycero-3-[phospho-l-choline], but also C18:1/OH lyso-PLs bearing the phosphoserine and phosphoethanolamine head groups, presented on albumin, were shown to signal for calcium flux in a self- and cross-desensitizing manner, implicating a single receptor. Blocking Abs to G2A inhibited calcium signaling by all three lyso-PLs. Furthermore, inhibition by both pertussis toxin and U-73122 established signaling via the Gαi/phospholipase C pathway for calcium mobilization. Altered plasma membrane localization of G2A has been hypothesized to facilitate signaling. Accordingly, an increase in detectable G2A was demonstrated by 1 min after lyso-PL stimulation and was followed by visible patching of the receptor. Western blotting showed that G2A resides in the plasma membrane/secretory vesicle fraction and not in neutrophil primary, secondary, or tertiary granules. Enhanced detection of G2A induced by lyso-PLs was paralleled by enhanced detection of CD45, confirming mobilization of the labile secretory vesicle pool. Together, these data show that lyso-PLs bearing various head groups redundantly mobilize G2A latent within secretory vesicles and result in G2A receptor/Gαi/phospholipase C signaling for calcium flux in neutrophils.

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Identification of 9-Hydroxyoctadecadienoic Acid and Other Oxidized Free Fatty Acids as Ligands of the G Protein-coupled Receptor G2A

Cited by 157 publications

References 42 publications

Activation of TRPV1 in the spinal cord by oxidized linoleic acid metabolites contributes to inflammatory hyperalgesia

Activation of TRPV1 in the spinal cord by oxidized linoleic acid metabolites contributes to inflammatory hyperalgesia

Do not let death do us part: ‘find-me’ signals in communication between dying cells and the phagocytes

Lysophospholipids of Different Classes Mobilize Neutrophil Secretory Vesicles and Induce Redundant Signaling through G2A

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