Article

A single N-terminal cysteine in TRPV1 determines activation by pungent compounds from onion and garlic.

Departamento de Biofísica, Instituto de Fisiología Celular, Circuito Exterior S/N, Ciudad Universitaria, Universidad Nacional Autónoma de México, México, D.F., 04510, Mexico.
Nature Neuroscience (Impact Factor: 14.98). 04/2008; 11(3):255-61. DOI: 10.1038/nn2056
Source: PubMed

ABSTRACT Some members of the transient receptor potential (TRP) family of cation channels mediate sensory responses to irritant substances. Although it is well known that TRPA1 channels are activated by pungent compounds found in garlic, onion, mustard and cinnamon extracts, activation of TRPV1 by these extracts remains controversial. Here we establish that TRPV1 is activated by pungent extracts from onion and garlic, as well as by allicin, the active compound in these preparations, and participates together with TRPA1 in the pain-related behavior induced by this compound. We found that in TRPV1 these agents act by covalent modification of cysteine residues. In contrast to TRPA1 channels, modification of a single cysteine located in the N-terminal region of TRPV1 was necessary and sufficient for all the effects we observed. Our findings point to a conserved mechanism of activation in TRP channels, which provides new insights into the molecular basis of noxious stimuli detection.

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Available from: Leon D Islas, Jul 29, 2015
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    • "Some compounds thought to be specific for the noxious cold receptor TRPA1 (see below) proved to activate TRPV1. This is the case of the pungent compound derived from onions, allicin (Macpherson et al., 2005; Salazar et al., 2008). The activation of TRPV1 is also produced by a fraction of the venom of the tarantula, Psalmopoeus cambridgei, that contains three cysteine knot (Kremeyer et al., 2010) peptides, dubbed vanillotoxins (Siemens et al., 2006). "
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    ABSTRACT: A class of ion channels that belongs to the transient receptor potential (TRP) superfamily and is present in specialized neurons that project to the skin has evolved as temperature detectors. These channels are classified into subfamilies, namely canonical (TRPC), melastatin (TRPM), ankyrin (TRPA), and vanilloid (TRPV). Some of these channels are activated by heat (TRPM2/4/5, TRPV1-4), while others by cold (TRPA1, TRPC5, and TRPM8). The general structure of these channels is closely related to that of the voltage-dependent K(+) channels, with their subunits containing six transmembrane segments that form tetramers. Thermal TRP channels are polymodal receptors. That is, they can be activated by temperature, voltage, pH, lipids, and agonists. The high temperature sensitivity in these thermal TRP channels is due to a large enthalpy change (∼100 kcal/mol), which is about five times the enthalpy change in voltage-dependent gating. The characterization of the macroscopic currents and single-channel analysis demonstrated that gating by temperature is complex and best described by branched or allosteric models containing several closed and open states. The identification of molecular determinants of temperature sensitivity in TRPV1, TRPA1, and TRPV3 strongly suggest that thermal sensitivity arises from a specific protein domain.
    Thermal Sensors, First edited by León Islas, Feng Qin, 11/2014: chapter Gating of Thermally Activated Channels: pages 51-87; Elsevier., ISBN: 1063-5823
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    • "These channels play an important role in mediating neurogenic inflammation and pain induced by noxious chemicals or thermal stimuli. TRPA1 channels have ankyrin-like repeats in the N terminus that are rich in cysteine residues (Bandell et al., 2007; Macpherson et al., 2007) and TRPV1 channels have extracellular cysteines (Jin et al., 2004; Susankova et al., 2006) that react with electrophiles and other thiol modifying species via Michael addition to alter channel gating and excitability (Bandell et al., 2004; Macpherson et al., 2007; Salazar et al., 2008). It has been proposed that OA-NO 2 covalently modifies the negatively charged cysteine of TRP channels leading to changes in channel function (Rudolph and Freeman, 2009). "
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    ABSTRACT: Nitro-oleic acid (OA-NO2), an electrophilic fatty acid nitroalkene byproduct of redox reactions, activates transient receptor potential ion channels (TRPA1 and TRPV1) in primary sensory neurons. To test the possibility that signaling actions of OA-NO2 might modulate TRP channels, we examined: (1) interactions between OA-NO2 and other agonists for TRPA1 (allyl-isothiocyanate, AITC) and TRPV1 (capsaicin) in rat dissociated dorsal root ganglion cells using Ca(2+) imaging and patch clamp techniques and (2) interactions between these agents on sensory nerves in the rat hindpaw. Ca(2+) imaging revealed that brief application (15-30sec) of each of the three agonists induced homologous desensitization. Heterologous desensitization also occurred when one agonist was applied prior to another agonist. OA-NO2 was more effective in desensitizing the response to AITC than the response to capsaicin. Prolonged exposure to OA-NO2 (20min) had a similar desensitizing effect on AITC or capsaicin. Homologous and heterologous desensitization were also demonstrated with patch clamp recording. Deltamethrin, a phosphatase inhibitor, reduced the capsaicin or AITC induced desensitization of OA-NO2 but did not suppress the OA-NO2 induced desensitization of AITC or capsaicin, indicating that heterologous desensitization induced by either capsaicin or AITC occurs by a different mechanism than the desensitization produced by OA-NO2. Subcutaneous injection of OA-NO2 (2.5mM, 35μL) into a rat hindpaw induced delayed and prolonged nociceptive behavior. Homologous desensitization occurred with AITC and capsaicin when applied at 15minute intervals, but did not occur with OA-NO2 when applied at a 30min interval. Pretreatment with OA-NO2 reduced AITC-evoked nociceptive behaviors but did not alter capsaicin responses. These results raise the possibility that OA-NO2 might be useful clinically to reduce neurogenic inflammation and certain types of painful sensations by desensitizing TRPA1 expressing nociceptive afferents.
    Experimental Neurology 11/2013; 251. DOI:10.1016/j.expneurol.2013.10.020 · 4.62 Impact Factor
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    • "OA-NO 2 activates TRPV1 and TRPA1 channels in sensory neurons (Sculptoreanu, et al., 2010, Taylor-Clark, et al., 2009). These channels play an important role in mediating neurogenic inflammation and pain induced by noxious chemicals or thermal stimuli, TRPA1 channels have ankyrin-like repeats in the N terminus that are rich in cysteine residues (Bandell, et al., 2007, Macpherson, et al., 2007) and TRPV1 channels have extracellular cysteines (Jin, et al., 2004, Susankova, et al., 2006) that react with electrophiles and other thiol modifying species via Michael addition to alter channel gating and excitability (Bandell, et al., 2004, Macpherson, et al., 2007, Salazar, et al., 2008). It has been proposed that OA-NO 2 covalently modifies the negatively charged cysteine of TRP channels leading to changes in channel function (Rudolph and Freeman, 2009). "
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    ABSTRACT: Nitro-oleic acid (9- and 10-nitro-octadeca-9-enoic acid, OA-NO(2)) is an electrophilic fatty acid nitroalkene derivative that modulates gene transcription and protein function via post-translational protein modification. Nitro-fatty acids are generated from unsaturated fatty acids by oxidative inflammatory reactions and acidic conditions in the presence of nitric oxide or nitrite. Nitroalkenes react with nucleophiles such as cysteine and histidine in a variety of susceptible proteins including transient receptor potential (TRP) channels in sensory neurons of the dorsal root and nodose ganglia. The present study revealed that OA-NO(2) activates TRP channels on afferent nerve terminals in the urinary bladder and thereby increases bladder activity. The TRPV1 agonist capsaicin (CAPS, 1 μM) and the TRPA1 agonist allyl isothiocyanate (AITC, 30 μM), elicited excitatory effects in bladder strips, increasing basal tone and amplitude of phasic bladder contractions (PBC). OA-NO(2) mimicked these effects in a concentration-dependent manner (1 μM-33 μM). The TRPA1 antagonist HC3-030031 (HC3, 30 μM) and the TRPV1 antagonist diaryl piperazine analog (DPA, 1 μM), reduced the effect of OA-NO(2) on phasic contraction amplitude and baseline tone. However, the non-selective TRP channel blocker, ruthenium red (30 μM) was a more effective inhibitor, reducing the effects of OA-NO(2) on basal tone by 75% and the effects on phasic amplitude by 85%. In bladder strips from CAPS-treated rats, the effect of OA-NO(2) on phasic contraction amplitude was reduced by 65% and the effect on basal tone was reduced by 60%. Pretreatment of bladder strips with a combination of neurokinin receptor antagonists (NK1 selective antagonist, CP 96345; NK2 selective antagonist, MEN 10,376; NK3 selective antagonist, SB 234,375, 1 μM each) reduced the effect of OA-NO(2) on basal tone, but not phasic contraction amplitude. These results indicate that nitroalkene fatty acid derivatives can activate TRP channels on CAPS-sensitive afferent nerve terminals, leading to increased bladder contractile activity. Nitrated fatty acids produced endogenously by the combination of fatty acids and oxides of nitrogen released from the urothelium and/or afferent nerves may play a role in modulating bladder activity.
    Experimental Neurology 08/2011; 232(1):90-9. DOI:10.1016/j.expneurol.2011.08.007 · 4.62 Impact Factor
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