A pain-inducing centipede toxin targets the heat activation machinery of nociceptor TRPV1.
Ontology highlight
ABSTRACT:
SUBMITTER: Yang S
PROVIDER: S-EPMC4589873 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The nociceptive transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal receptor for multiple painful stimuli, hence actively pursued as a target for analgesic drugs. We identified a small peptide toxin RhTx2 from the Chinese red-headed centipede that strongly modulates TRPV1 activities. RhTx2, a 31-amino-acid peptide, is similar to a TRPV1-activating toxin RhTx we have previously discovered but with four extra amino acids at the N terminus. We observed that, like RhTx, RhTx2 activated TRPV1, but RhTx2 rapidly desensitized the channel upon prolonged exposure. Desensitization was achieved by reducing both the open probability and the single-channel conductance. RhTx2 is not only a tool to study the desensitization mechanism of TRPV1, but also a promising starting molecule for developing novel analgesics.
| S-EPMC7388746 | biostudies-literature
Project description:Hyaluronan (HA) is present in the extracellular matrix of all body tissues, including synovial fluid in joints, in which it behaves as a filter that buffers transmission of mechanical forces to nociceptor nerve endings thereby reducing pain. Using recombinant systems, mouse-cultured dorsal root ganglia (DRG) neurons and in vivo experiments, we found that HA also modulates polymodal transient receptor potential vanilloid subtype 1 (TRPV1) channels. HA diminishes heat, pH and capsaicin (CAP) responses, thus reducing the opening probability of the channel by stabilizing its closed state. Accordingly, in DRG neurons, HA decreases TRPV1-mediated impulse firing and channel sensitization by bradykinin. Moreover, subcutaneous HA injection in mice reduces heat and capsaicin nocifensive responses, whereas the intra-articular injection of HA in rats decreases capsaicin joint nociceptor fibres discharge. Collectively, these results indicate that extracellular HA reduces the excitability of the ubiquitous TRPV1 channel, thereby lowering impulse activity in the peripheral nociceptor endings underlying pain.
| S-EPMC4560824 | biostudies-literature
Project description:Modulation of the function of somatosensory neurons is an important analgesic strategy, requiring the proposal of novel molecular targets. Many G-protein-coupled receptors (GPRs) have been deorphanized, but the receptor locations, outcomes due to their activations, and their signal transductions remain to be elucidated, regarding the somatosensory nociceptor function. Here we report that GPR171, expressed in a nociceptor subpopulation, attenuated pain signals via Gi/o-coupled modulation of the activities of nociceptive ion channels when activated by its newly found ligands. Administration of its natural peptide ligand and a synthetic chemical ligand alleviated nociceptor-mediated acute pain aggravations and also relieved pathologic pain at nanomolar and micromolar ranges. This study suggests that functional alteration of the nociceptor neurons by GPR171 signaling results in pain alleviation and indicates that GPR171 is a promising molecular target for peripheral pain modulation.
| S-EPMC8001436 | biostudies-literature
Project description:The intense pain induced by scorpion sting is a frequent clinical manifestation. To date, there is no established protocol with significant efficacy to alleviate the pain induced by scorpion envenomation. One of the important reasons is that, little information on pain-inducing compound from scorpion venoms is available. Here, a pain-inducing peptide (BmP01) has been identified and characterized from the venoms of scorpion (Mesobuthus martensii). In an animal model, intraplantar injection of BmP01 in mouse hind paw showed significant acute pain in wild type (WT) mice but not in TRPV1 knock-out (TRPV1 KO) mice during 30 min recording. BmP01 evoked currents in WT dorsal root ganglion (DRG) neurons but had no effect on DRG neurons of TRPV1 KO mice. Furthermore, OPEN ACCESS Toxins 2015, 7 3672 BmP01 evoked currents on TRPV1-expressed HEK293T cells, but not on HEK293T cells without TRPV1. These results suggest that (1) BmP01 is one of the pain-inducing agents in scorpion venoms; and (2) BmP01 induces pain by acting on TRPV1. To our knowledge, this is the first report about a scorpion toxin that produces pain by targeting TRPV1. Identification of a pain-inducing compound may facilitate treating pain induced by scorpion envenomation.
| S-EPMC4591660 | biostudies-literature
Project description:Coumarin and its derivatives are fragrant natural compounds isolated from the genus Murraya that are flowering plants widely distributed in East Asia, Australia, and the Pacific Islands. Murraya plants have been widely used as medicinal herbs for relief of pain, such as headache, rheumatic pain, toothache, and snake bites. However, little is known about their analgesic components and the molecular mechanism underlying pain relief. Here, we report the bioassay-guided fractionation and identification of a novel coumarin derivative, named muralatin L, that can specifically activate the nociceptor transient receptor potential vanilloid 1 (TRPV1) channel and reverse the inflammatory pain in mice through channel desensitization. Muralatin L was identified from the active extract of Murraya alata against TRPV1 transiently expressed in HEK-293T cells in fluorescent calcium FlexStation assay. Activation of TRPV1 current by muralatin L and its selectivity were further confirmed by whole-cell patch clamp recordings of TRPV1-expressing HEK-293T cells and dorsal root ganglion neurons isolated from mice. Furthermore, muralatin L could reverse inflammatory pain induced by formalin and acetic acid in mice but not in TRPV1 knock-out mice. Taken together, our findings show that muralatin L specifically activates TRPV1 and reverses inflammatory pain, thus highlighting the potential of coumarin derivatives from Murraya plants for pharmaceutical and medicinal applications such as pain therapy.
| S-EPMC4705384 | biostudies-literature
Project description:Transcriptional alterations are characteristic of persistent pain states but the key regulators remain elusive. Using a conditional knockout (cKO) strategy in mice we sought to determine whether loss of the transcriptional co-repressor histone deacetylase four (HDAC4) would have implications for sensory neuron transcription and nociception. HDAC4 was found to be largely dispensable for transcriptional regulation of naïve sensory neurons but was required for transcriptional responses after injury, with Calca and Trpv1 expression consistently downregulated in HDAC4 cKO compared to littermate controls (0.2-0.44 fold). This downregulation corresponded to reduced sensitivity to capsaicin in vitro (76% +/- 4.4% wildtype capsaicin responders vs 56.9% +/- 4.7% cKO responders) and to reduced thermal hypersensitivity in the complete Freund’s adjuvant model of inflammatory pain (1.3-1.4 fold improvement). These data indicate that HDAC4 is a novel inflammatory pain mediator and may be a good therapeutic target, capable of orchestrating the regulation of multiple downstream effectors. Total RNA was extracted from HDAC4 cKO and HDAC4 fl/fl naïve adult lumbar dorsal root ganglia (n=3/group). mRNA expression was compared using Affymetrix Mouse Gene Arrays (Mouse Gene 2.0ST) run on a GeneChip Fluidics Station 450. Chips were scanned on an Affymetrix GeneChip Scanner.
2015-04-23 | E-GEOD-62405 | biostudies-arrayexpress
Project description:Transcriptional alterations are characteristic of persistent pain states but the key regulators remain elusive. Using a conditional knockout (cKO) strategy in mice we sought to determine whether loss of the transcriptional co-repressor histone deacetylase four (HDAC4) would have implications for sensory neuron transcription and nociception. HDAC4 was found to be largely dispensable for transcriptional regulation of naïve sensory neurons but was required for transcriptional responses after injury, with Calca and Trpv1 expression consistently downregulated in HDAC4 cKO compared to littermate controls (0.2-0.44 fold). This downregulation corresponded to reduced sensitivity to capsaicin in vitro (76% +/- 4.4% wildtype capsaicin responders vs 56.9% +/- 4.7% cKO responders) and to reduced thermal hypersensitivity in the complete Freund’s adjuvant model of inflammatory pain (1.3-1.4 fold improvement). These data indicate that HDAC4 is a novel inflammatory pain mediator and may be a good therapeutic target, capable of orchestrating the regulation of multiple downstream effectors.
2015-04-23 | GSE62405 | GEO
Project description:The TRPV1 channel is a sensitive detector of pain-producing stimuli, including noxious heat, acid, inflammatory mediators, and vanilloid compounds. Although binding sites for some activators have been identified, the location of the temperature sensor remains elusive. Using available structures of TRPV1 and voltage-activated potassium channels, we engineered chimeras wherein transmembrane regions of TRPV1 were transplanted into the Shaker Kv channel. Here we show that transplanting the pore domain of TRPV1 into Shaker gives rise to functional channels that can be activated by a TRPV1-selective tarantula toxin that binds to the outer pore of the channel. This pore-domain chimera is permeable to Na+, K+, and Ca2+ ions, and remarkably, is also robustly activated by noxious heat. Our results demonstrate that the pore of TRPV1 is a transportable domain that contains the structural elements sufficient for activation by noxious heat.
| S-EPMC5777071 | biostudies-literature
Project description:Sensing noxiously high temperatures is crucial for living organisms to avoid heat-induced injury. The TRPV1 channel has long been known as a sensor for noxious heat. However, the mechanism of how this channel is activated by heat remains elusive. Here we found that a series of polyols including sucrose, sorbitol, and hyaluronan significantly elevate the heat activation threshold temperature of TRPV1. The modulatory effects of these polyols were only observed when they were perfused extracellularly. Interestingly, mutation of residues E601 and E649 in the outer pore region of TRPV1 largely abolished the effects of these polyols. We further observed that intraplantar injection of polyols into the hind paws of rats reduced their heat-induced pain response. Our observations not only suggest that the extracellular regions of TRPV1 are critical for the modulation of heat activation by polyols, but also indicate a potential role of polyols in reducing heat-induced pain sensation.
| S-EPMC8214097 | biostudies-literature
Project description:Purpose of reviewa)Osteoarthritis (OA) is the most common form of arthritis, and pain is the primary symptom of the disease, yet analgesic options for treating OA pain remain limited. In this review, we aimed to give an update on the current clinical and preclinical studies targeting two pathways that are being investigated for treating OA pain: the nerve growth factor (NGF) pathway and the transient receptor potential vanilloid-1 (TRPV1) pathway.Recent findingsb)Antibodies against NGF, small molecule inhibitors of TrkA, TRPV1 agonists, and TRPV1 antagonists are all in different stages of clinical and pre-clinical testing for the treatment of OA pain. NGF antibodies have shown efficacy in the primary endpoints tested compared to placebo, however, rapidly progressive OA has been consistently observed in a subset of patients and the cause remains unclear. TRPV1 agonists have also demonstrated reduced pain with no serious adverse events - the most common adverse events include a burning or warming sensation upon administration.Summaryc)Targeting the NGF and TRPV1 pathways appear effective for reducing OA pain, but further work is needed to better understand which patients may benefit most from these treatments. The anti-NGF antibody tanezumab and the TRPV1 agonist CNTX-4975 have both received fast-track designation from the FDA for the treatment of OA pain.
| S-EPMC8223492 | biostudies-literature