12 research outputs found
Differential mechanism of TRPV1 sensitization in peptidergic and nonpeptidergic nociceptors
No full textEl canal TRPV1 es un receptor polimodal, no selectivo a cationes, el cual actúa como principal integrador del estímulo doloroso en nociceptores. Durante la inflamación, los mediadores inflamatorios liberados actúan sobre TRPV1 provocando una excitabilidad aumentada del nociceptor y una hiperalgesia térmica. La sensibilización inflamatoria aguda de TRPV1 conlleva tanto la modificación de las propiedades de apertura del canal (“gating”) por fosforilación como al reclutamiento de nuevos canales a la membrana neuronal. La movilización del canal TRPV1 a la membrana plasmática provocada por algunos mediadores pro-inflamatorios tiene lugar a través de exocitosis dependiente de SNARE, aunque el mecanismo exacto no ha sido todavía esclarecido.
Con el fin de elucidar dicho mecanismo de exocitosis, nos planteamos la hipótesis de que el reclutamiento inflamatorio del canal TRPV1 ocurría únicamente en la subpoblación neuronal que contiene los neuropéptidos sustancia P (SP) y el péptido relacionado con el gen calcitonina (CGRP), también denominada nociceptores peptidérgicos. Así pues, se ha investigado la sensibilización inflamatoria del canal TRPV1 inducida por los agentes pro-inflamatorios Trifosfato de adenosina (ATP) y Bradiquinina (BK) en cultivos de nociceptores tanto peptidérgicos como no peptidérgicos. Para ello, se ha llevado a cabo el análisis funcional del canal TRPV1 empleando técnicas de electrofisiología patch clamp y MEA (matriz de microelectrodos). Nuestros resultados muestran que la inhibición de la exocitosis neuronal por parte del péptido DD04107 provoca una disminución en la sensibilización de TRPV1 inducida por los agentes pro- inflamatorios ATP y BK únicamente en la subpoblación peptidérgica. Además, la eliminación de la expresión de αCGRP también conduce a la reducción de la sensibilización inflamatoria de TRPV1. Así pues, este estudio revela que tanto ATP como BK inducen la exocitosis regulada de TRPV1 en nociceptores peptidérgicos donde αCGRP juega un papel significativo. Además, nuestros resultados validan el potencial terapéutico del péptido DD04107 en la disminución del dolor inflamatorio a través de la modulación de la exocitosis regulada de TRPV1.TRPV1 is a polymodal, non selective cation channel which acts as a major integrator of painful stimuli in nociceptors. During inflammation, the release of inflammatory mediators act on TRPV1 leading to enhanced nociceptor excitability and thermal hyperalgesia. Acute inflammatory sensitization of TRPV1 involves both the modification of channel gating properties by phosphorylation and recruitment of new channels to the neuronal surface. Mobilization of TRPV1 channel to the plasma membrane by some pro- inflammatory mediators occurs through SNARE-dependent exocytosis, but the exact mechanism involved remains to be elucidated. We hypothesize that the inflammatory recruitment of channels occurs in the neuronal subpopulation which contains neuropeptides substance P (SP) and calcitonin gene related peptide (CGRP), also called peptidergic nociceptors.
Therefore, we have investigated the underlying mechanism of pro- inflammatory mediators Adenosine triphosphate (ATP) and Bradykinin (BK) induced inflammatory sensitization of TRPV1 in cultured nociceptors containing both peptidergic and nonpeptidergic subpopulations. We have performed functional analysis using patch clamp electrophysiology and micro electrode array (MEA) technique. We found that the inhibition of neuronal exocytosis results in decreased inflammatory sensitization of TRPV1 induced by both ATP and Bradykinin in peptidergic nociceptors where membrane recruitment of the channel is essential. In addition, knocking out of αCGRP leads to the reduction of inflammatory sensitization of TRPV1.
Hence, this study reveals that both ATP and Bradykinin induces regulated exocytosis of TRPV1 in peptidergic nociceptors where αCGRP plays a significant role. Furthermore, our result validates the therapeutic potential of DD04107 on lessening inflammatory pain through modulation of regulated exocytosis of TRPV1
Bradykinin Induces TRPV1 Exocytotic Recruitment in Peptidergic Nociceptors
No full textTransient receptor potential vanilloid I (TRPV1) sensitization in peripheral nociceptors
is a prominent phenomenon that occurs in inflammatory pain conditions. Pro-algesic
agents can potentiate TRPV1 activity in nociceptors through both stimulation of its
channel gating and mobilization of channels to the neuronal surface in a context
dependent manner. A recent study reported that ATP-induced TRPV1 sensitization
in peptidergic nociceptors involves the exocytotic release of channels trafficked by
large dense core vesicles (LDCVs) that cargo alpha-calcitonin gene related peptide
alpha (αCGRP). We hypothesized that, similar to ATP, bradykinin may also use
different mechanisms to sensitize TRPV1 channels in peptidergic and non-peptidergic
nociceptors. We found that bradykinin notably enhances the excitability of peptidergic
nociceptors, and sensitizes TRPV1, primarily through the bradykinin receptor 2 pathway.
Notably, bradykinin sensitization of TRPV1 in peptidergic nociceptors was significantly
blocked by inhibiting Ca2+-dependent neuronal exocytosis. In addition, silencing
αCGRP gene expression, but not substance P, drastically reduced bradykinin-induced
TRPV1 sensitization in peptidergic nociceptors. Taken together, these findings indicate
that bradykinin-induced sensitization of TRPV1 in peptidergic nociceptors is partially
mediated by the exocytotic mobilization of new channels trafficked by αCGRP loaded LDCVs to the neuronal membrane. Our findings further imply a central role
of αCGRP peptidergic nociceptors in peripheral algesic sensitization, and substantiate
that inhibition of LDCVs exocytosis is a valuable therapeutic strategy to treat pain, as
it concurrently reduces the release of pro-inflammatory peptides and the membrane
recruitment of thermoTRP channel
αCGRP is essential for algesic exocytotic mobilization of TRPV1 channels in peptidergic nociceptors
No full textProalgesic sensitization of peripheral nociceptors in painful syn-dromes is a complex molecular process poorly understood thatinvolves mobilization of thermosensory receptors to the neuronalsurface. However, whether recruitment of vesicular thermoTRPchannels is a general mechanism underlying sensitization of allnociceptor types or is subtype-specific remains controversial. Wereport that sensitization-induced Ca2+-dependent exocytotic inser-tion of transient receptor potential vanilloid 1 (TRPV1) receptors tothe neuronal plasma membrane is a mechanism specifically usedby peptidergic nociceptors to potentiate their excitability. Notably,we found that TRPV1 is present in large dense-core vesicles(LDCVs) that were mobilized to the neuronal surface in responseto a sensitizing insult. Deletion or silencing of calcitonin-gene–related peptide alpha (αCGRP) gene expression drastically reducedproalgesic TRPV1 potentiation in peptidergic nociceptors by abro-gating its Ca2+-dependent exocytotic recruitment. These findingsuncover a context-dependent molecular mechanism of TRPV1 alge-sic sensitization and a previously unrecognized role of αCGRP inLDCV mobilization in peptidergic nociceptors. Furthermore, theseresults imply that concurrent secretion of neuropeptides and chan-nels in peptidergic C-type nociceptors facilitates a rapid modula-tion of pain signalin
Trafficking of ThermoTRP Channels
No full textThermoTRP channels (thermoTRPs) define a subfamily of the transient receptor potential (TRP) channels that are activated by changes in the environmental temperature, from noxious cold to injurious heat. Acting as integrators of several stimuli and signalling pathways, dysfunction of these channels contributes to several pathological states. The surface expression of thermoTRPs is controlled by both, the constitutive and regulated vesicular trafficking. Modulation of receptor surface density during pathological processes is nowadays considered as an interesting therapeutic approach for management of diseases, such as chronic pain, in which an increased trafficking is associated with the pathological state. This review will focus on the recent advances trafficking of the thermoTRP channels, TRPV1, TRPV2, TRPV4, TRPM3, TRPM8 and TRPA1, into/from the plasma membrane. Particularly, regulated membrane insertion of thermoTRPs channels contributes to a fine tuning of final channel activity, and indeed, it has resulted in the development of novel therapeutic approaches with successful clinical results such as disruption of SNARE-dependent exocytosis by botulinum toxin or botulinomimetic peptides
Use of the Genealogical Sorting Index (GSI) to delineate species boundaries in the Neofusicoccum parvum-Neofusicoccum ribis species complex
No full textNeofusicoccum is a recently described genus of common endophytes and pathogens of woody hosts, previously placed in the genus Botryosphaeria. Many morphological characteristics routinely used to describe species overlap in Neofusicoccum, and prior to the use of molecular phylogenetics, isolates from different hosts and locations were often misidentified. Two cryptic species Neofusicoccum ribis and Neofusicoccum parvum were initially described from different continents and recently another four species within this complex were described using fixed nucleotide polymorphisms for differentiation. In a survey of eucalypt cankers in eastern Australia, a collection of morphologically similar Neofusicoccum isolates were obtained. This collection was analysed within the framework of the morphological (MSRC), ecological (ESRC) and phylogenetic (PSRC) species recognition concepts. Morphological data based on spore measurements (MSRC), together with pathogenicity trials (ESRC) were considered alongside molecular analysis (PSRC), which included multiple gene phylogenies constructed from four nuclear gene regions. We also used the Genealogical Sorting Index method to provide objective evidence for the status of terminal taxa in the phylogenetic analysis. The isolates examined exhibited overlapping morphological and culture characteristics, similar pathogenicity to excised stems and shared hosts within the same locations. Phylogenetic analysis separated isolates into 8 clades corresponding to six described species: N. ribis, N. parvum, Neofusicoccum kwambonambiense, Neofusicoccum cordaticola, Neofusicoccum umdonicola, Neofusicoccum batangarum, and two new species. GSI support indicated combined phylogenetic data were monophyletic for all clades and all p-values were significant allowing us to reject the null hypothesis that all groups were from a single mixed group. Consequently the description of Neofusicoccum occulatum is presented
A Novel Agonist of the Type 1 Lysophosphatidic Acid Receptor (LPA1), UCM-05194, Shows Efficacy in Neuropathic Pain Amelioration
No full textABSTRACT: Neuropathic pain (NP) is a complex chronic
pain state with a prevalence of almost 10% in the general
population. Pharmacological options for NP are limited and
weakly effective, so there is a need to develop more efficacious
NP attenuating drugs. Activation of the type 1 lysophosphatidic acid (LPA1) receptor is a crucial factor in the initiation of
NP. Hence, it is conceivable that a functional antagonism
strategy could lead to NP mitigation. Here we describe a new
series of LPA1 agonists among which derivative (S)-17
(UCM-05194) stands out as the most potent and selective
LPA1 receptor agonist described so far (Emax = 118%, EC50 =
0.24 μM, KD = 19.6 nM; inactive at autotaxin and LPA2−6 receptors). This compound induces characteristic LPA1-mediated
cellular effects and prompts the internalization of the receptor leading to its functional inactivation in primary sensory neurons
and to an efficacious attenuation of the pain perception in an in vivo model of NP.Depto. de Química OrgánicaFac. de Ciencias QuímicasTRUEpu
A Novel Agonist of the Type 1 Lysophosphatidic Acid Receptor (LPA<sub>1</sub>), UCM-05194, Shows Efficacy in Neuropathic Pain Amelioration
No full textNeuropathic pain (NP) is a complex chronic pain state
with a prevalence
of almost 10% in the general population. Pharmacological options for
NP are limited and weakly effective, so there is a need to develop
more efficacious NP attenuating drugs. Activation of the type 1 lysophosphatidic
acid (LPA1) receptor is a crucial factor in the initiation
of NP. Hence, it is conceivable that a functional antagonism strategy
could lead to NP mitigation. Here we describe a new series of LPA1 agonists among which derivative (S)-17 (UCM-05194) stands out as the most potent and selective
LPA1 receptor agonist described so far (Emax = 118%, EC50 = 0.24 μM, KD = 19.6 nM; inactive at autotaxin and LPA2–6 receptors). This compound induces characteristic LPA1-mediated cellular effects and prompts the internalization of the
receptor leading to its functional inactivation in primary sensory
neurons and to an efficacious attenuation of the pain perception in
an in vivo model of NP
A Novel Agonist of the Type 1 Lysophosphatidic Acid Receptor (LPA<sub>1</sub>), UCM-05194, Shows Efficacy in Neuropathic Pain Amelioration
No full textNeuropathic pain (NP) is a complex chronic pain state
with a prevalence
of almost 10% in the general population. Pharmacological options for
NP are limited and weakly effective, so there is a need to develop
more efficacious NP attenuating drugs. Activation of the type 1 lysophosphatidic
acid (LPA1) receptor is a crucial factor in the initiation
of NP. Hence, it is conceivable that a functional antagonism strategy
could lead to NP mitigation. Here we describe a new series of LPA1 agonists among which derivative (S)-17 (UCM-05194) stands out as the most potent and selective
LPA1 receptor agonist described so far (Emax = 118%, EC50 = 0.24 μM, KD = 19.6 nM; inactive at autotaxin and LPA2–6 receptors). This compound induces characteristic LPA1-mediated cellular effects and prompts the internalization of the
receptor leading to its functional inactivation in primary sensory
neurons and to an efficacious attenuation of the pain perception in
an in vivo model of NP
