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Sample records for receptor potential vanilloid-1

  1. The transient receptor potential type vanilloid 1 suppresses skin carcinogenesis

    PubMed Central

    Bode, Ann M.; Cho, Yong-Yeon; Zheng, Duo; Zhu, Feng; Ericson, Marna E; Ma, Wei-Ya; Yao, Ke; Dong, Zigang

    2008-01-01

    Blockade of the transient receptor potential channel vanilloid subfamily 1 (TRPV1) is suggested as a therapeutic approach to pain relief. However, TRPV1 is a widely expressed protein whose function might be critical in various non-neuronal physiological conditions. The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is overexpressed in many human epithelial cancers and is a potential target for anticancer drugs. Here we show that TRPV1 interacts with the EGFR leading to EGFR degradation. Notably, the absence of TRPV1 in mice results in a striking increase in skin carcinogenesis. The TRPV1 is the first membrane receptor shown to have a tumor-suppressing effect associated with the downregulation of another membrane receptor. The data suggest that even though a great deal of interest has focused on the TRPV1 as a target for pain relief, the chronic blockade of this pain receptor might increase the risk for cancer development. PMID:19155296

  2. Structure-Driven Pharmacology of Transient Receptor Potential Channel Vanilloid 1.

    PubMed

    Díaz-Franulic, Ignacio; Caceres-Molina, Javier; Sepulveda, Romina V; Gonzalez-Nilo, Fernando; Latorre, Ramon

    2016-09-01

    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal receptor that mediates the flux of cations across the membrane in response to several stimuli, including heat, voltage, and ligands. The best known agonist of TRPV1 channels is capsaicin, the pungent component of "hot" chili peppers. In addition, peptides found in the venom of poisonous animals, along with the lipids phosphatidylinositol 4,5-biphosphate, lysophosphatidic acid, and cholesterol, bind to TRPV1 with high affinity to modulate channel gating. Here, we discuss the functional evidence regarding ligand-dependent activation of TRPV1 channels in light of structural data recently obtained by cryoelectron microscopy. This review focuses on the mechanistic insights into ligand binding and allosteric gating of TRPV1 channels and the relevance of accurate polymodal receptor biophysical characterization for drug design in novel pain therapies. PMID:27335334

  3. Structure-Driven Pharmacology of Transient Receptor Potential Channel Vanilloid 1.

    PubMed

    Díaz-Franulic, Ignacio; Caceres-Molina, Javier; Sepulveda, Romina V; Gonzalez-Nilo, Fernando; Latorre, Ramon

    2016-09-01

    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal receptor that mediates the flux of cations across the membrane in response to several stimuli, including heat, voltage, and ligands. The best known agonist of TRPV1 channels is capsaicin, the pungent component of "hot" chili peppers. In addition, peptides found in the venom of poisonous animals, along with the lipids phosphatidylinositol 4,5-biphosphate, lysophosphatidic acid, and cholesterol, bind to TRPV1 with high affinity to modulate channel gating. Here, we discuss the functional evidence regarding ligand-dependent activation of TRPV1 channels in light of structural data recently obtained by cryoelectron microscopy. This review focuses on the mechanistic insights into ligand binding and allosteric gating of TRPV1 channels and the relevance of accurate polymodal receptor biophysical characterization for drug design in novel pain therapies.

  4. Inhibitory effect of oleanolic acid from the rhizomes of Cyperus rotundus on transient receptor potential vanilloid 1 channel.

    PubMed

    Nam, Joo Hyun; Lee, Dong-Ung

    2015-01-01

    Cyperus rotundus is used as an analgesic and sedative in oriental medicine and has been reported to exhibit antinociceptive and anti-inflammatory effects. On the other hand, the transient receptor potential vanilloid 1 channel is a nonselective cation channel that senses various noxious chemical and thermal stimuli. However, it has recently been reported that the epidermally expressed transient receptor potential vanilloid 1 channel is involved in heat- and UV-induced skin aging. The aim of this study was to evaluate whether C. rotundus extract and its constituents can inhibit this channel. Ethylacetate and hexane fractions of the methanol extract were found to partially inhibit transient receptor potential vanilloid 1 channel activity, and at a concentration of 90 µM, oleanolic acid, which was one of three constituents isolated from the ethylacetate fraction, inhibited this activity by 61.4 ± 8.0 %. This is first electrophysiological study to be conducted on the effects of C. rotundus extract and its constituents on the transient receptor potential vanilloid 1 channel. The results obtained provide insight of the potential therapeutic effects of C. rotundus in the contexts of analgesia and UV-induced photoaging. PMID:25402944

  5. Transient receptor potential vanilloid 1 mediates pain in mice with severe sickle cell disease

    PubMed Central

    Kerstein, Patrick C.; Vilceanu, Daniel; Barabas, Marie E.; Retherford, Dawn; Brandow, Amanda M.; Wandersee, Nancy J.

    2011-01-01

    Pain is the leading cause of emergency department visits, hospitalizations, and daily suffering in individuals with sickle cell disease (SCD). The pathologic mechanisms leading to the perception of pain during acute RBC sickling episodes and development of chronic pain remain poorly understood and ineffectively treated. We provide the first study that explores nociceptor sensitization mechanisms that contribute to pain behavior in mice with severe SCD. Sickle mice exhibit robust behavioral hypersensitivity to mechanical, cold, and heat stimuli. Mechanical hypersensitivity is further exacerbated when hypoxia is used to induce acute sickling. Behavioral mechanical hypersensitivity is mediated in part by enhanced excitability to mechanical stimuli at both primary afferent peripheral terminal and sensory membrane levels. In the present study, inhibition of the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) with the selective antagonist A-425619 reversed the mechanical sensitization at both primary afferent terminals and isolated somata, and markedly attenuated mechanical behavioral hypersensitivity. In contrast, inhibition of TRPA1 with HC-030031 had no effect on mechanical sensitivity. These results suggest that the TRPV1 receptor contributes to primary afferent mechanical sensitization and a substantial portion of behavioral mechanical hypersensitivity in SCD mice. Therefore, TRPV1-targeted compounds that lack thermoregulatory side effects may provide relief from pain in patients with SCD. PMID:21708890

  6. Absence of transient receptor potential vanilloid-1 accelerates stress-induced axonopathy in the optic projection.

    PubMed

    Ward, Nicholas J; Ho, Karen W; Lambert, Wendi S; Weitlauf, Carl; Calkins, David J

    2014-02-26

    How neurons respond to stress in degenerative disease is of fundamental importance for identifying mechanisms of progression and new therapeutic targets. Members of the transient receptor potential (TRP) family of cation-selective ion channels are candidates for mediating stress signals, since different subunits transduce a variety of stimuli relevant in both normal and pathogenic physiology. We addressed this possibility for the TRP vanilloid-1 (TRPV1) subunit by comparing how the optic projection of Trpv1(-/-) mice and age-matched C57 controls responds to stress from elevated ocular pressure, the critical stressor in the most common optic neuropathy, glaucoma. Over a 5 week period of elevated pressure induced by microbead occlusion of ocular fluid, Trpv1(-/-) accelerated both degradation of axonal transport from retinal ganglion cells to the superior colliculus and degeneration of the axons themselves in the optic nerve. Ganglion cell body loss, which is normally later in progression, occurred in nasal sectors of Trpv1(-/-) but not C57 retina. Pharmacological antagonism of TRPV1 in rats similarly accelerated ganglion cell axonopathy. Elevated ocular pressure resulted in differences in spontaneous firing rate and action potential threshold current in Trpv1(-/-) ganglion cells compared with C57. In the absence of elevated pressure, ganglion cells in the two strains had similar firing patterns. Based on these data, we propose that TRPV1 may help neurons respond to disease-relevant stressors by enhancing activity necessary for axonal signaling.

  7. Involvement of Transient Receptor Potential Cation Channel Vanilloid 1 (TRPV1) in Myoblast Fusion.

    PubMed

    Kurosaka, Mitsutoshi; Ogura, Yuji; Funabashi, Toshiya; Akema, Tatsuo

    2016-10-01

    The mechanisms that underlie the complex process of muscle regeneration after injury remain unknown. Transient receptor potential cation channel vanilloid 1 (TRPV1) is expressed in several cell types, including skeletal muscle, and is activated by high temperature and by certain molecules secreted during tissue inflammation. Severe inflammation and local temperature perturbations are induced during muscle regeneration, which suggests that TRPV1 might be activated and involved in the process. The aim of this study, was to clarify the role of TRPV1 in the myogenic potential of satellite cells responsible for muscle regeneration. We found that mRNA and protein levels of TRPV1 increased during regeneration after cardiotoxin (CTX)-induced muscle injury in mice. Using isolated mouse satellite cells (i.e., myoblasts), we observed that activation of TRPV1 by its agonist capsaicin (CAP) augmented myogenin protein levels. Whereas CAP did not alter myoblast proliferation, it facilitated myoblast fusion (evaluated using myonucleii number per myotube and fusion index). In contrast, suppression of TRPV1 by siRNA impaired myoblast fusion. Using mice, we also demonstrated that intramuscular injection of CAP facilitated muscle repair after CTX-induced muscle injury. Moreover, we showed that these roles of TRPV1 might be mediated by interleukin-4 and calcium signaling during myoblast fusion. Collectively, these results suggest that TRPV1 underlies normal myogenesis through promotion of myoblast fusion. J. Cell. Physiol. 231: 2275-2285, 2016. © 2016 Wiley Periodicals, Inc. PMID:26892397

  8. Involvement of Transient Receptor Potential Cation Channel Vanilloid 1 (TRPV1) in Myoblast Fusion.

    PubMed

    Kurosaka, Mitsutoshi; Ogura, Yuji; Funabashi, Toshiya; Akema, Tatsuo

    2016-10-01

    The mechanisms that underlie the complex process of muscle regeneration after injury remain unknown. Transient receptor potential cation channel vanilloid 1 (TRPV1) is expressed in several cell types, including skeletal muscle, and is activated by high temperature and by certain molecules secreted during tissue inflammation. Severe inflammation and local temperature perturbations are induced during muscle regeneration, which suggests that TRPV1 might be activated and involved in the process. The aim of this study, was to clarify the role of TRPV1 in the myogenic potential of satellite cells responsible for muscle regeneration. We found that mRNA and protein levels of TRPV1 increased during regeneration after cardiotoxin (CTX)-induced muscle injury in mice. Using isolated mouse satellite cells (i.e., myoblasts), we observed that activation of TRPV1 by its agonist capsaicin (CAP) augmented myogenin protein levels. Whereas CAP did not alter myoblast proliferation, it facilitated myoblast fusion (evaluated using myonucleii number per myotube and fusion index). In contrast, suppression of TRPV1 by siRNA impaired myoblast fusion. Using mice, we also demonstrated that intramuscular injection of CAP facilitated muscle repair after CTX-induced muscle injury. Moreover, we showed that these roles of TRPV1 might be mediated by interleukin-4 and calcium signaling during myoblast fusion. Collectively, these results suggest that TRPV1 underlies normal myogenesis through promotion of myoblast fusion. J. Cell. Physiol. 231: 2275-2285, 2016. © 2016 Wiley Periodicals, Inc.

  9. Propacetamol-Induced Injection Pain Is Associated with Activation of Transient Receptor Potential Vanilloid 1 Channels.

    PubMed

    Schillers, Florian; Eberhardt, Esther; Leffler, Andreas; Eberhardt, Mirjam

    2016-10-01

    Propacetamol (PPCM) is a prodrug of paracetamol (PCM), which was generated to increase water solubility of PCM for intravenous delivery. PPCM is rapidly hydrolyzed by plasma esterases to PCM and diethylglycine and shares some structural and metabolic properties with lidocaine. Although PPCM is considered to be comparable to PCM regarding its analgesic properties, injection pain is a common side effect described for PPCM but not PCM. Injection pain is a frequent and unpleasant side effect of numerous drugs in clinical use, and previous reports have indicated that the ligand gated ion channels transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) can mediate this effect on sensory neurons. This study aimed to investigate molecular mechanisms by which PPCM, in contrast to PCM, causes injection pain. Therefore, human TRPV1 and TRPA1 receptors were expressed in human embryonic kidney 293 cells and investigated by means of whole-cell patch clamp and ratiometric calcium imaging. PPCM (but not PCM) activated TRPV1, sensitized heat-induced currents, and caused an increase in intracellular calcium. In TRPA1-expressing cells however, both PPCM and PCM evoked calcium responses but failed to induce inward currents. Intracutaneous injection of PPCM, but not of PCM, in human volunteers induced an intense and short-lasting pain and an increase in superficial blood flow, indicating activation of nociceptive C fibers and subsequent neuropeptide release. In conclusion, activation of human TRPV1 by PPCM seems to be a relevant mechanism for induction of pain upon intracutaneous injection and thus also for pain reported as an adverse side effect upon intravenous administration. PMID:27457427

  10. Propacetamol-Induced Injection Pain Is Associated with Activation of Transient Receptor Potential Vanilloid 1 Channels.

    PubMed

    Schillers, Florian; Eberhardt, Esther; Leffler, Andreas; Eberhardt, Mirjam

    2016-10-01

    Propacetamol (PPCM) is a prodrug of paracetamol (PCM), which was generated to increase water solubility of PCM for intravenous delivery. PPCM is rapidly hydrolyzed by plasma esterases to PCM and diethylglycine and shares some structural and metabolic properties with lidocaine. Although PPCM is considered to be comparable to PCM regarding its analgesic properties, injection pain is a common side effect described for PPCM but not PCM. Injection pain is a frequent and unpleasant side effect of numerous drugs in clinical use, and previous reports have indicated that the ligand gated ion channels transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) can mediate this effect on sensory neurons. This study aimed to investigate molecular mechanisms by which PPCM, in contrast to PCM, causes injection pain. Therefore, human TRPV1 and TRPA1 receptors were expressed in human embryonic kidney 293 cells and investigated by means of whole-cell patch clamp and ratiometric calcium imaging. PPCM (but not PCM) activated TRPV1, sensitized heat-induced currents, and caused an increase in intracellular calcium. In TRPA1-expressing cells however, both PPCM and PCM evoked calcium responses but failed to induce inward currents. Intracutaneous injection of PPCM, but not of PCM, in human volunteers induced an intense and short-lasting pain and an increase in superficial blood flow, indicating activation of nociceptive C fibers and subsequent neuropeptide release. In conclusion, activation of human TRPV1 by PPCM seems to be a relevant mechanism for induction of pain upon intracutaneous injection and thus also for pain reported as an adverse side effect upon intravenous administration.

  11. Mechanisms of transient receptor potential vanilloid 1 activation and sensitization by allyl isothiocyanate.

    PubMed

    Gees, Maarten; Alpizar, Yeranddy A; Boonen, Brett; Sanchez, Alicia; Everaerts, Wouter; Segal, Andrei; Xue, Fenqin; Janssens, Annelies; Owsianik, Grzegorz; Nilius, Bernd; Voets, Thomas; Talavera, Karel

    2013-09-01

    Allyl isothiocyanate (AITC; aka, mustard oil) is a powerful irritant produced by Brassica plants as a defensive trait against herbivores and confers pungency to mustard and wasabi. AITC is widely used experimentally as an inducer of acute pain and neurogenic inflammation, which are largely mediated by the activation of nociceptive cation channels transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 (TRPV1). Although it is generally accepted that electrophilic agents activate these channels through covalent modification of cytosolic cysteine residues, the mechanism underlying TRPV1 activation by AITC remains unknown. Here we show that, surprisingly, AITC-induced activation of TRPV1 does not require interaction with cysteine residues, but is largely dependent on S513, a residue that is involved in capsaicin binding. Furthermore, AITC acts in a membrane-delimited manner and induces a shift of the voltage dependence of activation toward negative voltages, which is reminiscent of capsaicin effects. These data indicate that AITC acts through reversible interactions with the capsaicin binding site. In addition, we show that TRPV1 is a locus for cross-sensitization between AITC and acidosis in nociceptive neurons. Furthermore, we show that residue F660, which is known to determine the stimulation by low pH in human TRPV1, is also essential for the cross-sensitization of the effects of AITC and low pH. Taken together, these findings demonstrate that not all reactive electrophiles stimulate TRPV1 via cysteine modification and help understanding the molecular bases underlying the surprisingly large role of this channel as mediator of the algesic properties of AITC.

  12. The role of endogenous molecules in modulating pain through transient receptor potential vanilloid 1 (TRPV1)

    PubMed Central

    Morales-Lázaro, Sara L; Simon, Sidney A; Rosenbaum, Tamara

    2013-01-01

    Pain is a physiological response to a noxious stimulus that decreases the quality of life of those sufferring from it. Research aimed at finding new therapeutic targets for the treatment of several maladies, including pain, has led to the discovery of numerous molecular regulators of ion channels in primary afferent nociceptive neurons. Among these receptors is TRPV1 (transient receptor potential vanilloid 1), a member of the TRP family of ion channels. TRPV1 is a calcium-permeable channel, which is activated or modulated by diverse exogenous noxious stimuli such as high temperatures, changes in pH, and irritant and pungent compounds, and by selected molecules released during tissue damage and inflammatory processes. During the last decade the number of endogenous regulators of TRPV1's activity has increased to include lipids that can negatively regulate TRPV1, as is the case for cholesterol and PIP2 (phosphatidylinositol 4,5-biphosphate) while, in contrast, other lipids produced in response to tissue injury and ischaemic processes are known to positively regulate TRPV1. Among the latter, lysophosphatidic acid activates TRPV1 while amines such as N-acyl-ethanolamines and N-acyl-dopamines can sensitize or directly activate TRPV1. It has also been found that nucleotides such as ATP act as mediators of chemically induced nociception and pain and gases, such as hydrogen sulphide and nitric oxide, lead to TRPV1 activation. Finally, the products of lipoxygenases and omega-3 fatty acids among other molecules, such as divalent cations, have also been shown to endogenously regulate TRPV1 activity. Here we provide a comprehensive review of endogenous small molecules that regulate the function of TRPV1. Acting through mechanisms that lead to sensitization and desensitization of TRPV1, these molecules regulate pathways involved in pain and nociception. Understanding how these compounds modify TRPV1 activity will allow us to comprehend how some pathologies are associated with

  13. The role of endogenous molecules in modulating pain through transient receptor potential vanilloid 1 (TRPV1).

    PubMed

    Morales-Lázaro, Sara L; Simon, Sidney A; Rosenbaum, Tamara

    2013-07-01

    Pain is a physiological response to a noxious stimulus that decreases the quality of life of those sufferring from it. Research aimed at finding new therapeutic targets for the treatment of several maladies, including pain, has led to the discovery of numerous molecular regulators of ion channels in primary afferent nociceptive neurons. Among these receptors is TRPV1 (transient receptor potential vanilloid 1), a member of the TRP family of ion channels. TRPV1 is a calcium-permeable channel, which is activated or modulated by diverse exogenous noxious stimuli such as high temperatures, changes in pH, and irritant and pungent compounds, and by selected molecules released during tissue damage and inflammatory processes. During the last decade the number of endogenous regulators of TRPV1's activity has increased to include lipids that can negatively regulate TRPV1, as is the case for cholesterol and PIP2 (phosphatidylinositol 4,5-biphosphate) while, in contrast, other lipids produced in response to tissue injury and ischaemic processes are known to positively regulate TRPV1. Among the latter, lysophosphatidic acid activates TRPV1 while amines such as N-acyl-ethanolamines and N-acyl-dopamines can sensitize or directly activate TRPV1. It has also been found that nucleotides such as ATP act as mediators of chemically induced nociception and pain and gases, such as hydrogen sulphide and nitric oxide, lead to TRPV1 activation. Finally, the products of lipoxygenases and omega-3 fatty acids among other molecules, such as divalent cations, have also been shown to endogenously regulate TRPV1 activity. Here we provide a comprehensive review of endogenous small molecules that regulate the function of TRPV1. Acting through mechanisms that lead to sensitization and desensitization of TRPV1, these molecules regulate pathways involved in pain and nociception. Understanding how these compounds modify TRPV1 activity will allow us to comprehend how some pathologies are associated with

  14. Nerve growth factor contribution via transient receptor potential vanilloid 1 to ectopic orofacial pain.

    PubMed

    Shinoda, Masamichi; Asano, Masatake; Omagari, Daisuke; Honda, Kuniya; Hitomi, Suzuro; Katagiri, Ayano; Iwata, Koichi

    2011-05-11

    It is well known that oral inflammation causes tenderness in temporomandibular joints or masseter muscles. The exact mechanism of such an orofacial ectopic hyperalgesia remains unclear. Here, we investigated the functional significance of interaction of nerve growth factor (NGF) and transient receptor potential vanilloid 1 (TRPV1) in relation to heat hyperalgesia in the whisker pad skin caused by complete Freund's adjuvant (CFA) injection into the lower lip. CFA injection induced heat hyperalgesia of the ipsilateral whisker pad skin. Moreover, it leads to enhancement of spontaneous activity and heat responses in trigeminal ganglion (TG) neurons that was elicited by heat stimulation of the whisker pad skin. The heat hyperalgesia was dose-dependently reversed by intraperitoneal TRPV1 antagonist administration, also diminished by neutralizing anti-NGF antibody administration into the lower lip and intraganglionic administration of K252a, a tyrosine kinase receptor inhibitor. Nerve fibers in bundle of mandibular nerve and TG neurons that innervates the whisker pad skin and lower lip both expressed labeled NGF, which was administrated into the lower lip. Moreover, the NGF concentrations in ophthalmic-maxillary and mandibular divisions of the TG increased after CFA injection into the lower lip. The number of TRPV1-positive neurons that innervates the whisker pad skin and lower lip was increased after CFA injection into the lower lip, and this increase was annulled by anti-NGF administration. The present findings suggest that inflammation in the lower lip induces release of NGF that regulates TRPV1 expression in TG neurons. This TRPV1 overexpression may underlie ectopic heat hyperalgesia in the whisker pad skin.

  15. Coarse architecture of the transient receptor potential vanilloid 1 (TRPV1) ion channel determined by fluorescence resonance energy transfer.

    PubMed

    De-la-Rosa, Víctor; Rangel-Yescas, Gisela E; Ladrón-de-Guevara, Ernesto; Rosenbaum, Tamara; Islas, León D

    2013-10-11

    The transient receptor potential vanilloid 1 ion channel is responsible for the perception of high temperatures and low extracellular pH, and it is also involved in the response to some pungent compounds. Importantly, it is also associated with the perception of pain and noxious stimuli. Here, we attempt to discern the molecular organization and location of the N and C termini of the transient receptor potential vanilloid 1 ion channel by measuring FRET between genetically attached enhanced yellow and cyan fluorescent protein to the N or C terminus of the channel protein, expressed in transfected HEK 293 cells or Xenopus laevis oocytes. The static measurements of the domain organization were mapped into an available cryo-electron microscopy density of the channel with good agreement. These measurements also provide novel insights into the organization of terminal domains and their proximity to the plasma membrane. PMID:23965996

  16. Transient Receptor Potential Vanilloid 1 Expression and Functionality in MCF-7 Cells: A Preliminary Investigation

    PubMed Central

    Barbero, Raffaella; Cuniberti, Barbara; Racca, Silvia; Abbadessa, Giuliana; Piccione, Francesca; Re, Giovanni

    2014-01-01

    Purpose Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel belonging to the transient receptor potential family, and it is expressed in different neoplastic tissues. Its activation is associated with regulation of cancer growth and progression. The aim of this research was to study the expression and pharmacological characteristics of TRPV1 in cells derived from human breast cancer MCF-7 cells. Methods TRPV1 presence was assessed by binding studies and Western blotting. Receptor binding characteristics were evaluated through competition assays, while 3-(4,5-dimethylthiazol-2-yl)-2,5,-dipheyltetrazolium bromide reduction assays were performed to confirm an early hypothesis regarding the modulation of cancer cell proliferation. The functionality of TRPV1 was evaluated by measuring Ca2+ uptake in the presence of increasing concentrations of TRPV1 agonists and antagonists. Results Binding studies identified a single class of TRPV1 (Bmax 1,492±192 fmol/mg protein), and Western blot showed a signal at 100 kDa corresponding to the molecular weight of human TRPV1. Among the different tested agonists and antagonists, anandamide (Ki: 2.8×10-11 M) and 5-iodoresiniferatoxin (5-I-RTX) (Ki: 5.6×10-11 M) showed the highest degrees of affinity for TRPV1, respectively. All tested TRPV1 agonists and antagonists caused a significant (p<0.05) decrease in cell growth rate in MCF-7 cells. For agonists and antagonists, the efficacy of tested compounds displayed the following rank order: resiniferatoxin>anandamide>capsaicin and 5-I-RTX=capsazepine, respectively. Conclusion These data indicate that both TRPV1 agonists and antagonists induce significant inhibition of MCF-7 cell growth. Even though the mechanisms involved in the antiproliferative effects of TRPV1 agonists and antagonists should be further investigated, it has been suggested that agonists cause desensitization of the receptor, leading to alteration in Ca2+-influx regulation. By contrast

  17. Cannabinoid receptor 1 suppresses transient receptor potential vanilloid 1-induced inflammatory responses to corneal injury

    PubMed Central

    Yang, Y.; Yang, H.; Wang, Z.; Varadaraj, K.; Kumari, S.S.; Mergler, S.; Okada, Y.; Saika, S.; Kingsley, P.J.; Marnett, L.J.; Reinach, P.S.

    2013-01-01

    Cannabinoid receptor type 1 (CB1)-induced suppression of transient receptor potential vanilloid type 1 (TRPV1) activation provides a therapeutic option to reduce inflammation and pain in different animal disease models through mechanisms involving dampening of TRPV1 activation and signaling events. As we found in both mouse corneal epithelium and human corneal epithelial cells (HCEC) that there is CB1 and TRPV1 expression colocalization based on overlap of coimmunostaining, we determined in mouse corneal wound healing models and in human corneal epithelial cells (HCEC) if they interact with one another to reduce TRPV1-induced inflammatory and scarring responses. Corneal epithelial debridement elicited in vivo a more rapid wound healing response in wildtype (WT) than in CB1−/− mice suggesting functional interaction between CB1 and TRPV1. CB1 activation by injury is tenable based on the identification in mouse corneas of 2-arachidonylglycerol (2-AG) with tandem LC–MS/MS, a selective endocannabinoid CB1 ligand. Suppression of corneal TRPV1 activation by CB1 is indicated since following alkali burning, CB1 activation with WIN55,212-2 (WIN) reduced immune cell stromal infiltration and scarring. Western blot analysis of coimmunoprecipitates identified protein–protein interaction between CB1 and TRPV1. Other immunocomplexes were also identified containing transforming growth factor kinase 1 (TAK1), TRPV1 and CB1. CB1 siRNA gene silencing prevented suppression by WIN of TRPV1-induced TAK1–JNK1 signaling. WIN reduced TRPV1-induced Ca2+ transients in fura2-loaded HCEC whereas pertussis toxin (PTX) preincubation obviated suppression by WIN of such rises caused by capsaicin (CAP). Whole cell patch clamp analysis of HCEC showed that WIN blocked subsequent CAP-induced increases in nonselective outward currents. Taken together, CB1 activation by injury-induced release of endocannabinoids such as 2-AG downregulates TRPV1 mediated inflammation and corneal opacification

  18. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature

    PubMed Central

    Alawi, Khadija M.; Aubdool, Aisah A.; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D.; Keeble, Julie E.

    2015-01-01

    Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders.—Alawi, K. M., Aubdool, A. A., Liang, L., Wilde, E., Vepa, A., Psefteli, M.-P., Brain, S. D., Keeble, J. E. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature. PMID:26136480

  19. Transient receptor potential vanilloid-1-mediated calcium responses are inhibited by the alkylamine antihistamines dexbrompheniramine and chlorpheniramine.

    PubMed

    Sadofsky, Laura R; Campi, Barbara; Trevisani, Marcello; Compton, Steven J; Morice, Alyn H

    2008-12-01

    American guidelines, unlike European guidelines, support the use of antihistamines as a first line of treatment for some causes of chronic cough. Transient receptor potential vanilloid-1 (TRPV1) is an ion channel activated by the tussive agents capsaicin, resiniferatoxin, and protons. It is predominantly expressed by C-fiber and some Adelta -fiber sensory neurons and is thought to be a cough receptor. By measuring increases in intracellular calcium as an indicator of TRPV1 activation, the authors sought to determine whether antihistamines could antagonise TRPV1 permanently expressed in HEK and Pro5 cells and TRPV1 endogenously expressed in rat dorsal root ganglia neurons. In human TRPV1-expressing HEK cells (hTRPV1-HEK), diphenhydramine and fexofenadine failed to inhibit capsaicin-triggered calcium responses. However, both dexbrompheniramine and chlorpheniramine significantly inhibited capsaicin-evoked responses in hTRPV1-HEK. Dexbrompheniramine also inhibited activation of rat TRPV1 expressed in HEK and Pro5 cells, without interfering with TRPA1 and proteinase-activated receptor-2 (PAR(2)) activation. Finally, in rat dorsal root ganglia neuron preparations, dexbrompheniramine dose-dependently inhibited capsaicin-evoked calcium responses. Thus, the inhibition of TRPV1 activation by dexbrompheniramine may provide one potential mechanism whereby this antihistamine exerts its therapeutic effect in chronic cough.

  20. The sympathetic nervous system is controlled by transient receptor potential vanilloid 1 in the regulation of body temperature.

    PubMed

    Alawi, Khadija M; Aubdool, Aisah A; Liang, Lihuan; Wilde, Elena; Vepa, Abhinav; Psefteli, Maria-Paraskevi; Brain, Susan D; Keeble, Julie E

    2015-10-01

    Transient receptor potential vanilloid 1 (TRPV1) is involved in sensory nerve nociceptive signaling. Recently, it has been discovered that TRPV1 receptors also regulate basal body temperature in multiple species from mice to humans. In the present study, we investigated whether TRPV1 modulates basal sympathetic nervous system (SNS) activity. C57BL6/J wild-type (WT) mice and TRPV1 knockout (KO) mice were implanted with radiotelemetry probes for measurement of core body temperature. AMG9810 (50 mg/kg) or vehicle (2% DMSO/5% Tween 80/10 ml/kg saline) was injected intraperitoneally. Adrenoceptor antagonists or vehicle (5 ml/kg saline) was injected subcutaneously. In WT mice, the TRPV1 antagonist, AMG9810, caused significant hyperthermia, associated with increased noradrenaline concentrations in brown adipose tissue. The hyperthermia was significantly attenuated by the β-adrenoceptor antagonist propranolol, the mixed α-/β-adrenoceptor antagonist labetalol, and the α1-adrenoceptor antagonist prazosin. TRPV1 KO mice have a normal basal body temperature, indicative of developmental compensation. d-Amphetamine (potent sympathomimetic) caused hyperthermia in WT mice, which was reduced in TRPV1 KO mice, suggesting a decreased sympathetic drive in KOs. This study provides new evidence that TRPV1 controls thermoregulation upstream of the SNS, providing a potential therapeutic target for sympathetic hyperactivity thermoregulatory disorders.

  1. Pharmacology of modality-specific transient receptor potential vanilloid-1 antagonists that do not alter body temperature.

    PubMed

    Reilly, Regina M; McDonald, Heath A; Puttfarcken, Pamela S; Joshi, Shailen K; Lewis, LaGeisha; Pai, Madhavi; Franklin, Pamela H; Segreti, Jason A; Neelands, Torben R; Han, Ping; Chen, Jun; Mantyh, Patrick W; Ghilardi, Joseph R; Turner, Teresa M; Voight, Eric A; Daanen, Jerome F; Schmidt, Robert G; Gomtsyan, Arthur; Kort, Michael E; Faltynek, Connie R; Kym, Philip R

    2012-08-01

    The transient receptor potential vanilloid-1 (TRPV1) channel is involved in the development and maintenance of pain and participates in the regulation of temperature. The channel is activated by diverse agents, including capsaicin, noxious heat (≥ 43°C), acidic pH (< 6), and endogenous lipids including N-arachidonoyl dopamine (NADA). Antagonists that block all modes of TRPV1 activation elicit hyperthermia. To identify efficacious TRPV1 antagonists that do not affect temperature antagonists representing multiple TRPV1 pharmacophores were evaluated at recombinant rat and human TRPV1 channels with Ca(2+) flux assays, and two classes of antagonists were identified based on their differential ability to inhibit acid activation. Although both classes of antagonists completely blocked capsaicin- and NADA-induced activation of TRPV1, select compounds only partially inhibited activation of the channel by protons. Electrophysiology and calcitonin gene-related peptide release studies confirmed the differential pharmacology of these antagonists at native TRPV1 channels in the rat. Comparison of the in vitro pharmacological properties of these TRPV1 antagonists with their in vivo effects on core body temperature confirms and expands earlier observations that acid-sparing TRPV1 antagonists do not significantly increase core body temperature. Although both classes of compounds elicit equivalent analgesia in a rat model of knee joint pain, the acid-sparing antagonist tested is not effective in a mouse model of bone cancer pain.

  2. Transient Receptor Potential Vanilloid 1 Activation Enhances Gut Glucagon-Like Peptide-1 Secretion and Improves Glucose Homeostasis

    PubMed Central

    Wang, Peijian; Yan, Zhencheng; Zhong, Jian; Chen, Jing; Ni, Yinxing; Li, Li; Ma, Liqun; Zhao, Zhigang; Liu, Daoyan; Zhu, Zhiming

    2012-01-01

    Type 2 diabetes mellitus (T2DM) is rapidly prevailing as a serious global health problem. Current treatments for T2DM may cause side effects, thus highlighting the need for newer and safer therapies. We tested the hypothesis that dietary capsaicin regulates glucose homeostasis through the activation of transient receptor potential vanilloid 1 (TRPV1)-mediated glucagon-like peptide-1 (GLP-1) secretion in the intestinal cells and tissues. Wild-type (WT) and TRPV1 knockout (TRPV1−/−) mice were fed dietary capsaicin for 24 weeks. TRPV1 was localized in secretin tumor cell-1 (STC-1) cells and ileum. Capsaicin stimulated GLP-1 secretion from STC-1 cells in a calcium-dependent manner through TRPV1 activation. Acute capsaicin administration by gastric gavage increased GLP-1 and insulin secretion in vivo in WT but not in TRPV1−/− mice. Furthermore, chronic dietary capsaicin not only improved glucose tolerance and increased insulin levels but also lowered daily blood glucose profiles and increased plasma GLP-1 levels in WT mice. However, this effect was absent in TRPV1−/− mice. In db/db mice, TRPV1 activation by dietary capsaicin ameliorated abnormal glucose homeostasis and increased GLP-1 levels in the plasma and ileum. The present findings suggest that TRPV1 activation–stimulated GLP-1 secretion could be a promising approach for the intervention of diabetes. PMID:22664955

  3. Cyclin-dependent kinase 5 modulates nociceptive signaling through direct phosphorylation of transient receptor potential vanilloid 1

    PubMed Central

    Pareek, Tej K.; Keller, Jason; Kesavapany, Sashi; Agarwal, Nitin; Kuner, Rohini; Pant, Harish C.; Iadarola, Michael J.; Brady, Roscoe O.; Kulkarni, Ashok B.

    2007-01-01

    Transient receptor potential vanilloid 1 (TRPV1), a ligand-gated cation channel highly expressed in small-diameter sensory neurons, is activated by heat, protons, and capsaicin. The phosphorylation of TRPV1 provides a versatile regulation of intracellular calcium levels and is critical for TRPV1 function in responding to a pain stimulus. We have previously reported that cyclin-dependent kinase 5 (Cdk5) activity regulates nociceptive signaling. In this article we report that the Cdk5-mediated phosphorylation of TRPV1 at threonine-407 can modulate agonist-induced calcium influx. Inhibition of Cdk5 activity in cultured dorsal root ganglia neurons resulted in a significant reduction of TRPV1-mediated calcium influx, and this effect could be reversed by restoring Cdk5 activity. Primary nociceptor-specific Cdk5 conditional-knockout mice showed reduced TRPV1 phosphorylation, resulting in significant hypoalgesia. Thus, the present study indicates that Cdk5-mediated TRPV1 phosphorylation is important in the regulation of pain signaling. PMID:17194758

  4. Effects of the transient receptor potential vanilloid 1 antagonist A-425619 on body temperature and thermoregulation in the rat.

    PubMed

    Mills, C; McMackin, M; Jaffe, R; Yu, J; Zininberg, E; Slee, D; Gogas, K; Bradbury, M

    2008-09-22

    Transient receptor potential vanilloid 1 (TRPV1) receptor antagonists have gained much attention for their potential to treat inflammatory and neuropathic pain. However, systemic administration of TRPV1 antagonists induces a period of hyperthermia, a potential liability for small molecule development. Here we characterize the effects of the TRPV1 antagonist A-425619 on body temperature (T(b)) in the rat when administered: (1) alone at different times of the circadian cycle, (2) as repeated hourly or daily treatment, (3) as pre-treatment to prevent capsaicin-induced hypothermia, (4) to capsaicin-desensitized animals, and (5) prior to a heat challenge. Changes in T(b) were compared with compound exposure data, locomotor activity, and time course of efficacy in inflammatory pain models. Without affecting locomotor activity, oral administration of A-425619 induced a transient period of hyperthermia that was followed by a period of hypothermia, a profile unique among reported TRPV1 antagonists. Repeated hourly administration of A-425619 produced an increase in T(b) similar to a single administration. A-425619 had no effect on T(b) when administered to capsaicin-desensitized rats. The duration of A-425619-induced hyperthermia, but not hypothermia, was dependent on the time of the circadian cycle when administered. Pre-treatment with A-425619 attenuated capsaicin-induced hypothermia and did not potentiate T(b) or alter thermoregulatory behavioral responses during a heat challenge. These results indicate that A-425619-induced hyperthermia is transient, circadian-dependent, not related to exposure levels, locomotor activity, or time course of analgesic action, and does not affect the ability to thermoregulate during a heat challenge.

  5. Transient receptor potential vanilloid 1 channels modulate the anxiolytic effect of diazepam.

    PubMed

    Manna, Shyamshree S S; Umathe, Sudhir N

    2011-11-24

    The present study investigated the interaction between the vanilloid and GABAergic systems on anxiety. Swiss mice were subjected to social interaction test, an animal model for assessing anxiety-related behavior, after intracerebroventricular administration of capsaicin, (TRPV1 agonist) or capsazepine, (TRPV1 antagonist) either alone or in combination with traditional anxiolytic drug, diazepam. Results showed that capsaicin (1, 10, and 100 μg/mouse) decreased the interaction time exhibiting an anxiogenic-like response, while capsazepine (10, and 100 μg/mouse) produced anxiolytic-like response similar to that of diazepam (0.25-4 mg/kg, i.p). Prior administration of capsaicin at a dose, inactive per se (0.1 μg/mouse) attenuated the anxiolytic effect of diazepam, whereas, co-administration of capsazepine and diazepam both in their sub-effective as well as effective doses exhibited significant anxiolytic-like effect. Interestingly, the combined treatment of diazepam (2mg/kg) and capsazepine (100μg/mouse) produced no sedative or locomotor deficit effects. On the contrary, a higher dose of diazepam (>2mg/kg) alone was found to be a sedative or locomotor depressant, indicating that the anxiolytic effect of diazepam, at least in part involve TRPV1 receptor. Morever, capsazepine pretreatment blocked the anxiogenic effect of capsaicin (1, and 100 μg/mouse). Taken together, these findings suggest that blockade of TRPV1 might be a functional tool to prevent the risks associated with the long-term use of benzodiazepines.

  6. Transient receptor potential vanilloid-1 (TRPV1) is a mediator of lung toxicity for coal fly ash particulate material.

    PubMed

    Deering-Rice, Cassandra E; Johansen, Mark E; Roberts, Jessica K; Thomas, Karen C; Romero, Erin G; Lee, Jeewoo; Yost, Garold S; Veranth, John M; Reilly, Christopher A

    2012-03-01

    Environmental particulate matter (PM) pollutants adversely affect human health, but the molecular basis is poorly understood. The ion channel transient receptor potential vanilloid-1 (TRPV1) has been implicated as a sensor for environmental PM and a mediator of adverse events in the respiratory tract. The objectives of this study were to determine whether TRPV1 can distinguish chemically and physically unique PM that represents important sources of air pollution; to elucidate the molecular basis of TRPV1 activation by PM; and to ascertain the contributions of TRPV1 to human lung cell and mouse lung tissue responses exposed to an insoluble PM agonist, coal fly ash (CFA1). The major findings of this study are that TRPV1 is activated by some, but not all of the prototype PM materials evaluated, with rank-ordered responses of CFA1 > diesel exhaust PM > crystalline silica; TRP melastatin-8 is also robustly activated by CFA1, whereas other TRP channels expressed by airway sensory neurons and lung epithelial cells that may also be activated by CFA1, including TRPs ankyrin 1 (A1), canonical 4α (C4α), M2, V2, V3, and V4, were either slightly (TRPA1) or not activated by CFA1; activation of TRPV1 by CFA1 occurs via cell surface interactions between the solid components of CFA1 and specific amino acid residues of TRPV1 that are localized in the putative pore-loop region; and activation of TRPV1 by CFA1 is not exclusive in mouse lungs but represents a pathway by which CFA1 affects the expression of selected genes in lung epithelial cells and airway tissue.

  7. Spatio-Temporal Expression and Functional Involvement of Transient Receptor Potential Vanilloid 1 in Diabetic Mechanical Allodynia in Rats

    PubMed Central

    Wu, Huang-Hui; Qi, Jian; Shi, Juan; Li, Yun-Qing

    2014-01-01

    Diabetic neuropathic pain (DNP) is one of the most common clinical manifestations of diabetes mellitus (DM), which is characterized by prominent mechanical allodynia (DMA). However, the molecular mechanism underlying it has not fully been elucidated. In this study, we examined the spatio-temporal expression of a major nociceptive channel protein transient receptor potential vanilloid 1 (TRPV1) and analyzed its functional involvement by intrathecal (i.t.) application of TRPV1 antagonists in streptozocin (STZ)-induced DMA rat models. Western blot and immunofluorescent staining results showed that TRPV1 protein level was significantly increased in the soma of the dorsal root ganglion (DRG) neurons on 14 days after STZ treatment (DMA 14 d), whereas those in spinal cord and skin (mainly from the central and peripheral processes of DRG neurons) had already been enhanced on DMA 7 d to peak on DMA 14 d. qRT-PCR experiments confirmed that TRPV1 mRNA level was significantly up-regulated in the DRG on DMA 7 d, indicating a preceding translation of TRPV1 protein in the soma but preferential distribution of this protein to the processes under the DMA conditions. Cell counting assay based on double immunostaining suggested that increased TRPV1-immunoreactive neurons were likely to be small-sized and CGRP-ergic. Finally, single or multiple intrathecal applications of non-specific or specific TRPV1 antagonists, ruthenium red and capsazepine, at varying doses, effectively alleviated DMA, although the effect of the former was more prominent and long-lasting. These results collectively indicate that TRPV1 expression dynamically changes during the development of DMA and this protein may play important roles in mechanical nociception in DRG neurons, presumably through facilitating the release of CGRP. PMID:25020137

  8. Role of the outer pore domain in transient receptor potential vanilloid 1 dynamic permeability to large cations.

    PubMed

    Munns, Clare H; Chung, Man-Kyo; Sanchez, Yuly E; Amzel, L Mario; Caterina, Michael J

    2015-02-27

    Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-D-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity.

  9. Role of the Outer Pore Domain in Transient Receptor Potential Vanilloid 1 Dynamic Permeability to Large Cations*

    PubMed Central

    Munns, Clare H.; Chung, Man-Kyo; Sanchez, Yuly E.; Amzel, L. Mario; Caterina, Michael J.

    2015-01-01

    Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-d-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity. PMID:25568328

  10. Transient Receptor Potential Vanilloid-1 (TRPV1) Is a Mediator of Lung Toxicity for Coal Fly Ash Particulate Material

    PubMed Central

    Deering-Rice, Cassandra E.; Johansen, Mark E.; Roberts, Jessica K.; Thomas, Karen C.; Romero, Erin G.; Lee, Jeewoo; Yost, Garold S.; Veranth, John M.

    2012-01-01

    Environmental particulate matter (PM) pollutants adversely affect human health, but the molecular basis is poorly understood. The ion channel transient receptor potential vanilloid-1 (TRPV1) has been implicated as a sensor for environmental PM and a mediator of adverse events in the respiratory tract. The objectives of this study were to determine whether TRPV1 can distinguish chemically and physically unique PM that represents important sources of air pollution; to elucidate the molecular basis of TRPV1 activation by PM; and to ascertain the contributions of TRPV1 to human lung cell and mouse lung tissue responses exposed to an insoluble PM agonist, coal fly ash (CFA1). The major findings of this study are that TRPV1 is activated by some, but not all of the prototype PM materials evaluated, with rank-ordered responses of CFA1 > diesel exhaust PM > crystalline silica; TRP melastatin-8 is also robustly activated by CFA1, whereas other TRP channels expressed by airway sensory neurons and lung epithelial cells that may also be activated by CFA1, including TRPs ankyrin 1 (A1), canonical 4α (C4α), M2, V2, V3, and V4, were either slightly (TRPA1) or not activated by CFA1; activation of TRPV1 by CFA1 occurs via cell surface interactions between the solid components of CFA1 and specific amino acid residues of TRPV1 that are localized in the putative pore-loop region; and activation of TRPV1 by CFA1 is not exclusive in mouse lungs but represents a pathway by which CFA1 affects the expression of selected genes in lung epithelial cells and airway tissue. PMID:22155782

  11. Desensitization of transient receptor potential ankyrin 1 (TRPA1) by the TRP vanilloid 1-selective cannabinoid arachidonoyl-2 chloroethanolamine.

    PubMed

    Ruparel, Nikita B; Patwardhan, Amol M; Akopian, Armen N; Hargreaves, Kenneth M

    2011-07-01

    Recent studies on cannabinoid-induced analgesia implicate certain transient receptor potential (TRP) channels as a therapeutic target along with metabotropic cannabinoid receptors. Although TRP ankyrin 1 (TRPA1)-selective cannabinoids, such as (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl) pyrrolo-[1,2,3-d,e]-1,4-benzoxazin-6-yl]-1-naphthalenyl-methanone (WIN55,212), are effective at desensitizing TRPA1 and TRP vanilloid 1 (TRPV1), there is a gap in knowledge in understanding the opposite situation, namely whether TRPV1-selective cannabinoids desensitize TRPA1. We selected the TRPV1-specific synthetic cannabinoid, arachidonoyl-2 chloroethanolamine (ACEA), to study peripheral antihyperalgesic properties because ACEA is known to activate TRPV1. Hence, we used in vitro as well as in vivo assays to evaluate the following: 1) the effects of ACEA on the TRPA1-selective agonist, mustard oil (MO), for calcitonin gene-related peptide (CGRP) release from rat hindpaw skin in vitro; 2) the effects of a peripherally selective dose of ACEA on MO-induced nocifensive behavior in vivo; and 3) the effects of five ACEA-insensitive TRPV1 mutations on ACEA-inhibition of MO-evoked calcium accumulation using a Chinese hamster ovary cell expression system. Our results demonstrate that 1) ACEA significantly attenuated (∼40%) MO-evoked CGRP release from rat hindpaw skin, and this effect was not antagonized by the TRPV1 antagonist, capsazepine; 2) ACEA significantly inhibited (∼40%) MO-induced nocifensive behavior in wild-type mice but not in TRPV1 knockout mice; and 3) all TRPV1 mutations insensitive to ACEA lacked the ability to inhibit MO-evoked calcium accumulation in Chinese hamster ovary cells transfected with TRPV1 and TRPA1. Taken together, the results indicate that a TRPV1-selective cannabinoid, ACEA, inhibits MO-evoked responses via a TRPV1-dependent mechanism. This study strengthens the hypothesis that cannabinoids mediate their peripheral analgesic properties, at least

  12. Novel transient receptor potential vanilloid 1 receptor antagonists for the treatment of pain: structure-activity relationships for ureas with quinoline, isoquinoline, quinazoline, phthalazine, quinoxaline, and cinnoline moieties.

    PubMed

    Gomtsyan, Arthur; Bayburt, Erol K; Schmidt, Robert G; Zheng, Guo Zhu; Perner, Richard J; Didomenico, Stanley; Koenig, John R; Turner, Sean; Jinkerson, Tammie; Drizin, Irene; Hannick, Steven M; Macri, Bryan S; McDonald, Heath A; Honore, Prisca; Wismer, Carol T; Marsh, Kennan C; Wetter, Jill; Stewart, Kent D; Oie, Tetsuro; Jarvis, Michael F; Surowy, Carol S; Faltynek, Connie R; Lee, Chih-Hung

    2005-02-10

    Novel transient receptor potential vanilloid 1 (TRPV1) receptor antagonists with various bicyclic heteroaromatic pharmacophores were synthesized, and their in vitro activity in blocking capsaicin activation of TRPV1 was assessed. On the basis of the contribution of these pharmacophores to the in vitro potency, they were ranked in the order of 5-isoquinoline > 8-quinoline = 8-quinazoline > 8-isoquinoline > or = cinnoline approximately phthalazine approximately quinoxaline approximately 5-quinoline. The 5-isoquinoline-containing compound 14a (hTRPV1 IC50 = 4 nM) exhibited 46% oral bioavailability and in vivo activity in animal models of visceral and inflammatory pain. Pharmacokinetic and pharmacological properties of 14a are substantial improvements over the profile of the high-throughput screening hit 1 (hTRPV1 IC50 = 22 nM), which was not efficacious in animal pain models and was not orally bioavailable.

  13. Regulation of the temperature-dependent activation of transient receptor potential vanilloid 1 (TRPV1) by phospholipids in planar lipid bilayers.

    PubMed

    Sun, Xiaohui; Zakharian, Eleonora

    2015-02-20

    TRPV1 (transient receptor potential vanilloid 1) proteins are heat-activated nonselective cation channels. TRPV1 channels are polymodal in their function and exhibit multifaceted regulation with various molecular compounds. In this regard, phosphoinositides, particularly phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 4-phosphate, are important channel regulators. However, their effects on TRPV1 channel activity have not been conclusively determined. To characterize temperature-induced activation of TRPV1 in the presence of different phospholipids, we purified the TRPV1 protein from HEK-293 cells and incorporated it into planar lipid bilayers. In the presence of 2.5 μm phosphatidylinositol 4,5-bisphosphate, TRPV1 channels demonstrated rapid activation at 33-39 °C and achieved full channel opening at 42 °C. At this temperature range, TRPV1 heat activation exhibited steep temperature dependence (temperature coefficient (Q10) of 18), and the channel openings were accompanied by large changes in entropy and enthalpy, suggesting a substantial conformation change. At a similar temperature range, another phosphoinositide, phosphatidylinositol 4-phosphate, also potentiated heat activation of TRPV1, but with much lower efficiency. Negatively charged phosphatidylglycerol could also induce heat activation of TRPV1 channels, although with a small-conductance state. Our data demonstrate that phospholipids, specifically phosphoinositides, are important regulators of TRPV1 and are required for heat-induced channel activity.

  14. Involvement of perivascular nerves and transient receptor potential vanilloid 1 (TRPV1) in vascular responses to histamine in rat mesenteric resistance arteries.

    PubMed

    Jin, Honghua; Sun, Pengyuan; Takatori, Shingo; Koyama, Toshihiro; Zamami, Yoshito; Tangsucharit, Panot; Kitamura, Yoshihisa; Kawasaki, Hiromu

    2012-04-01

    A previous report showed that histamine in denuded mesenteric vascular beds produced a triphasic response; an initial small histamine H(2) receptor-mediated vasodilation, a transient histamine H(1) receptor-mediated vasoconstriction, and finally a long-lasting vasodilation. We further investigated the vascular effect of histamine in mesenteric preparations without an endothelium to clarify the possible involvement of perivascular nerves. Male Wistar rat mesenteric vascular beds without an endothelium were perfused with Krebs solution containing methoxamine to produce active tone and lafutidine to block histamine H(2) receptor-mediated vasodilation. Histamine (1-100μM) was perfused for 1min and perfusion pressure was measured with a pressure transducer. Histamine caused a biphasic vascular response; initial vasoconstriction followed vasodilation. Tetrodotoxin (a neurotoxin, 1μM) and procaine (a local anesthetic, 100μM) significantly inhibited the vasoconstriction and vasodilation. Ruthenium red (a transient receptor potential vanilloid 1 (TRPV1) antagonist, 1μM) also significantly inhibited both phases of the response. Pretreatment with capsaicin (a depletor of calcitonin gene-related peptide (CGRP)-containing nerves, 5μM) significantly inhibited the vasodilation without affecting the initial vasoconstriction. Both indomethacin (a cyclooxygenase inhibitor, 0.5μM) and seratrodast (a thromboxane A(2) receptor antagonist, 0.1μM) abolished the histamine-induced vasoconstriction and subsequent vasodilation. These results suggest that histamine-induced vasoconstriction and long-lasting vasodilation are mediated by activation of TRPV1 on capsaicin-sensitive and capsaicin-insensitive nerves. They also suggest that perivascular nerves and prostanoids, probably thromboxane A(2), are responsible for the vascular response to histamine.

  15. 20-Hydroxyeicosatetraenoic acid (20-HETE) is a novel activator of transient receptor potential vanilloid 1 (TRPV1) channel.

    PubMed

    Wen, Hairuo; Östman, Johan; Bubb, Kristen J; Panayiotou, Catherine; Priestley, John V; Baker, Mark D; Ahluwalia, Amrita

    2012-04-20

    TRPV1 is a member of the transient receptor potential ion channel family and is gated by capsaicin, the pungent component of chili pepper. It is expressed predominantly in small diameter peripheral nerve fibers and is activated by noxious temperatures >42 °C. 20-Hydroxyeicosatetraenoic acid (20-HETE) is a cytochrome P-450 4A/4F-derived metabolite of the membrane phospholipid arachidonic acid. It is a powerful vasoconstrictor and has structural similarities with other TRPV1 agonists, e.g. the hydroperoxyeicosatetraenoic acid 12-HPETE, and we hypothesized that it may be an endogenous ligand for TRPV1 in sensory neurons innervating the vasculature. Here, we demonstrate that 20-HETE both activates and sensitizes mouse and human TRPV1, in a kinase-dependent manner, involving the residue Ser(502) in heterologously expressed hTRPV1, at physiologically relevant concentrations. PMID:22389490

  16. NOX3 NADPH oxidase couples transient receptor potential vanilloid 1 to signal transducer and activator of transcription 1-mediated inflammation and hearing loss.

    PubMed

    Mukherjea, Debashree; Jajoo, Sarvesh; Sheehan, Kelly; Kaur, Tejbeer; Sheth, Sandeep; Bunch, Jennifer; Perro, Christopher; Rybak, Leonard P; Ramkumar, Vickram

    2011-03-15

    Transient receptor potential vanilloid 1 (TRPV1) is implicated in cisplatin ototoxicity. Activation of this channel by cisplatin increases reactive oxygen species generation, which contribute to loss of outer hair cells in the cochlea. Knockdown of TRPV1 by short interfering RNA protected against cisplatin ototoxicity. In this study, we examined the mechanism underlying TRPV1-mediated ototoxicity using cultured organ of Corti transformed cells (UB/OC-1) and rats. Trans-tympanic injections of capsaicin produced transient hearing loss within 24 h, which recovered by 72 h. In UB/OC-1 cells, capsaicin increased NOX3 NADPH oxidase activity and activation of signal transducer and activator of transcription 1 (STAT1). Intratympanic administration of capsaicin transiently increased STAT1 activity and expression of downstream proinflammatory molecules. Capsaicin produced a transient increase in CD14-positive inflammatory cells into the cochlea, which mimicked the temporal course of STAT1 activation but did not alter the expression of apoptotic genes or damage to outer hair cells. In addition, trans-tympanic administration of STAT1 short interfering RNA protected against capsaicin-induced hearing loss. These data suggest that activation of TRPV1 mediates temporary hearing loss by initiating an inflammatory process in the cochlea via activation of NOX3 and STAT1. Thus, these proteins represent reasonable targets for ameliorating hearing loss.

  17. NOX3 NADPH Oxidase Couples Transient Receptor Potential Vanilloid 1 to Signal Transducer and Activator of Transcription 1-Mediated Inflammation and Hearing Loss

    PubMed Central

    Mukherjea, Debashree; Jajoo, Sarvesh; Sheehan, Kelly; Kaur, Tejbeer; Sheth, Sandeep; Bunch, Jennifer; Perro, Christopher; Rybak, Leonard P.

    2011-01-01

    Abstract Transient receptor potential vanilloid 1 (TRPV1) is implicated in cisplatin ototoxicity. Activation of this channel by cisplatin increases reactive oxygen species generation, which contribute to loss of outer hair cells in the cochlea. Knockdown of TRPV1 by short interfering RNA protected against cisplatin ototoxicity. In this study, we examined the mechanism underlying TRPV1-mediated ototoxicity using cultured organ of Corti transformed cells (UB/OC-1) and rats. Trans-tympanic injections of capsaicin produced transient hearing loss within 24 h, which recovered by 72 h. In UB/OC-1 cells, capsaicin increased NOX3 NADPH oxidase activity and activation of signal transducer and activator of transcription 1 (STAT1). Intratympanic administration of capsaicin transiently increased STAT1 activity and expression of downstream proinflammatory molecules. Capsaicin produced a transient increase in CD14-positive inflammatory cells into the cochlea, which mimicked the temporal course of STAT1 activation but did not alter the expression of apoptotic genes or damage to outer hair cells. In addition, trans-tympanic administration of STAT1 short interfering RNA protected against capsaicin-induced hearing loss. These data suggest that activation of TRPV1 mediates temporary hearing loss by initiating an inflammatory process in the cochlea via activation of NOX3 and STAT1. Thus, these proteins represent reasonable targets for ameliorating hearing loss. Antioxid. Redox Signal. 14, 999–1010. PMID:20712533

  18. Activation of transient receptor potential vanilloid-1 (TRPV1) influences how retinal ganglion cell neurons respond to pressure-related stress

    PubMed Central

    Sappington, Rebecca M; Sidorova, Tatiana; Ward, Nicholas J; Chakravarthy, Rohini; Ho, Karen W; Calkins, David J

    2015-01-01

    Our recent studies implicate the transient receptor potential vanilloid-1 (TRPV1) channel as a mediator of retinal ganglion cell (RGC) function and survival. With elevated pressure in the eye, TRPV1 increases in RGCs, supporting enhanced excitability, while Trpv1 -/- accelerates RGC degeneration in mice. Here we find TRPV1 localized in monkey and human RGCs, similar to rodents. Expression increases in RGCs exposed to acute changes in pressure. In retinal explants, contrary to our animal studies, both Trpv1 -/- and pharmacological antagonism of the channel prevented pressure-induced RGC apoptosis, as did chelation of extracellular Ca2+. Finally, while TRPV1 and TRPV4 co-localize in some RGC bodies and form a protein complex in the retina, expression of their mRNA is inversely related with increasing ocular pressure. We propose that TRPV1 activation by pressure-related insult in the eye initiates changes in expression that contribute to a Ca2+-dependent adaptive response to maintain excitatory signaling in RGCs. PMID:25713995

  19. NOX3 NADPH oxidase couples transient receptor potential vanilloid 1 to signal transducer and activator of transcription 1-mediated inflammation and hearing loss.

    PubMed

    Mukherjea, Debashree; Jajoo, Sarvesh; Sheehan, Kelly; Kaur, Tejbeer; Sheth, Sandeep; Bunch, Jennifer; Perro, Christopher; Rybak, Leonard P; Ramkumar, Vickram

    2011-03-15

    Transient receptor potential vanilloid 1 (TRPV1) is implicated in cisplatin ototoxicity. Activation of this channel by cisplatin increases reactive oxygen species generation, which contribute to loss of outer hair cells in the cochlea. Knockdown of TRPV1 by short interfering RNA protected against cisplatin ototoxicity. In this study, we examined the mechanism underlying TRPV1-mediated ototoxicity using cultured organ of Corti transformed cells (UB/OC-1) and rats. Trans-tympanic injections of capsaicin produced transient hearing loss within 24 h, which recovered by 72 h. In UB/OC-1 cells, capsaicin increased NOX3 NADPH oxidase activity and activation of signal transducer and activator of transcription 1 (STAT1). Intratympanic administration of capsaicin transiently increased STAT1 activity and expression of downstream proinflammatory molecules. Capsaicin produced a transient increase in CD14-positive inflammatory cells into the cochlea, which mimicked the temporal course of STAT1 activation but did not alter the expression of apoptotic genes or damage to outer hair cells. In addition, trans-tympanic administration of STAT1 short interfering RNA protected against capsaicin-induced hearing loss. These data suggest that activation of TRPV1 mediates temporary hearing loss by initiating an inflammatory process in the cochlea via activation of NOX3 and STAT1. Thus, these proteins represent reasonable targets for ameliorating hearing loss. PMID:20712533

  20. Transient Receptor Potential Vanilloid 1 Gene Deficiency Ameliorates Hepatic Injury in a Mouse Model of Chronic Binge Alcohol-Induced Alcoholic Liver Disease

    PubMed Central

    Liu, Huilin; Beier, Juliane I.; Arteel, Gavin E.; Ramsden, Christopher E.; Feldstein, Ariel E.; McClain, Craig J.; Kirpich, Irina A.

    2016-01-01

    Experimental alcohol-induced liver injury is exacerbated by a high polyunsaturated fat diet rich in linoleic acid. We postulated that bioactive oxidized linoleic acid metabolites (OXLAMs) play a critical role in the development/progression of alcohol-mediated hepatic inflammation and injury. OXLAMs are endogenous ligands for transient receptor potential vanilloid 1 (TRPV1). Herein, we evaluated the role of signaling through TRPV1 in an experimental animal model of alcoholic liver disease (ALD). Chronic binge alcohol administration increased plasma OXLAM levels, specifically 9- and 13-hydroxy-octadecadienoic acids. This effect was associated with up-regulation of hepatic TRPV1. Exposure of hepatocytes to these OXLAMs in vitro resulted in activation of TRPV1 signal transduction with increased intracellular Ca2+ levels. Genetic depletion of TRPV1 did not blunt hepatic steatosis caused by ethanol, but prevented hepatic injury. TRPV1 deficiency protected from hepatocyte death and prevented the increase in proinflammatory cytokine and chemokine expression, including tumor necrosis factor-α, IL-6, macrophage inflammatory protein-2, and monocyte chemotactic protein 1. TRPV1 depletion markedly blunted ethanol-mediated induction of plasminogen activator inhibitor-1, an important alcohol-induced hepatic inflammation mediator, via fibrin accumulation. This study indicates, for the first time, that TRPV1 receptor pathway may be involved in hepatic inflammatory response in an experimental animal model of ALD. TRPV1-OXLAM interactions appear to play a significant role in hepatic inflammation/injury, further supporting an important role for dietary lipids in ALD. PMID:25447051

  1. Molecular Cloning and Functional Characterization of Xenopus tropicalis Frog Transient Receptor Potential Vanilloid 1 Reveal Its Functional Evolution for Heat, Acid, and Capsaicin Sensitivities in Terrestrial Vertebrates*

    PubMed Central

    Ohkita, Masashi; Saito, Shigeru; Imagawa, Toshiaki; Takahashi, Kenji; Tominaga, Makoto; Ohta, Toshio

    2012-01-01

    The functional difference of thermosensitive transient receptor potential (TRP) channels in the evolutionary context has attracted attention, but thus far little information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, which diverged earliest from terrestrial vertebrate lineages. In this study we cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by measuring changes in the intracellular calcium concentration ([Ca2+]i). The channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays ∼60% sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin induced [Ca2+]i increases in xtTRPV1-HeLa and xtDRG neurons and evoked nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low compared with mammalian orthologues. Low extracellular pH and heat activated xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes expressing xtTRPV1, inward currents were elicited by heat and low extracellular pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 561) were responsible for the low sensitivity to capsaicin. Taken together, our results indicate that xtTRPV1 functions as a polymodal receptor similar to its mammalian orthologues. The present study demonstrates that TRPV1 functions as a heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. Because it is possible to examine vanilloid and heat sensitivities in vitro and in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal for the study of TRPV1 function. PMID:22130664

  2. H2O2 generated by NADPH oxidase 4 contributes to transient receptor potential vanilloid 1 channel-mediated mechanosensation in the rat kidney.

    PubMed

    Lin, Chian-Shiung; Lee, Shang-Hsing; Huang, Ho-Shiang; Chen, Yih-Sharng; Ma, Ming-Chieh

    2015-08-15

    The presence of NADPH oxidase (Nox) in the kidney, especially Nox4, results in H2O2 production, which regulates Na(+) excretion and urine formation. Redox-sensitive transient receptor potential vanilloid 1 channels (TRPV1s) are distributed in mechanosensory fibers of the renal pelvis and monitor changes in intrapelvic pressure (IPP) during urine formation. The present study tested whether H2O2 derived from Nox4 affects TRPV1 function in renal sensory responses. Perfusion of H2O2 into the renal pelvis dose dependently increased afferent renal nerve activity and substance P (SP) release. These responses were attenuated by cotreatment with catalase or TRPV1 blockers. In single unit recordings, H2O2 activated afferent renal nerve activity in response to rising IPP but not high salt. Western blots revealed that Nox2 (gp91(phox)) and Nox4 are both present in the rat kidney, but Nox4 is abundant in the renal pelvis and originates from dorsal root ganglia. This distribution was associated with expression of the Nox4 regulators p22(phox) and polymerase δ-interacting protein 2. Coimmunoprecipitation experiments showed that IPP increases polymerase δ-interacting protein 2 association with Nox4 or p22(phox) in the renal pelvis. Interestingly, immunofluorescence labeling demonstrated that Nox4 colocalizes with TRPV1 in sensory fibers of the renal pelvis, indicating that H2O2 generated from Nox4 may affect TRPV1 activity. Stepwise increases in IPP and saline loading resulted in H2O2 and SP release, sensory activation, diuresis, and natriuresis. These effects, however, were remarkably attenuated by Nox inhibition. Overall, these results suggest that Nox4-positive fibers liberate H2O2 after mechanostimulation, thereby contributing to a renal sensory nerve-mediated diuretic/natriuretic response. PMID:26136558

  3. Streptozotocin-Induced Early Thermal Hyperalgesia is independent of Glycemic State of Rats: Role of Transient Receptor Potential Vanilloid 1(TRPV1) and Inflammatory mediators

    PubMed Central

    2011-01-01

    Background Streptozotocin (STZ) is used as a common tool to induce diabetes and to study diabetes-induced complications including diabetic peripheral neuropathy (DPN). Previously, we have reported that STZ induces a direct effect on neurons through expression and function of the Transient receptor potential vanilloid 1 (TRPV1) channel in sensory neurons resulting in thermal hyperalgesia, even in non-diabetic STZ-treated mice. In the present study, we investigated the role of expression and function of TRPV1 in the central sensory nerve terminals in the spinal cord in STZ-induced hyperalgesia in rats. Results We found that a proportion of STZ-treated rats were normoglycemic but still exhibited thermal hyperalgesia and mechanical allodynia. Immunohistochemical data show that STZ treatment, irrespective of glycemic state of the animal, caused microglial activation and increased expression of TRPV1 in spinal dorsal horn. Further, there was a significant increase in the levels of pro-inflammatory mediators (IL-1β, IL-6 and TNF-α) in spinal cord tissue, irrespective of the glycemic state. Capsaicin-stimulated release of calcitonin gene related peptide (CGRP) was significantly higher in the spinal cord of STZ-treated animals. Intrathecal administration of resiniferatoxin (RTX), a potent TRPV1 agonist, significantly attenuated STZ-induced thermal hyperalgesia, but not mechanical allodynia. RTX treatment also prevented the increase in TRPV1-mediated neuropeptide release in the spinal cord tissue. Conclusions From these results, it is concluded that TRPV1 is an integral component of initiating and maintaining inflammatory thermal hyperalgesia, which can be alleviated by intrathecal administration of RTX. Further, the results suggest that enhanced expression and inflammation-induced sensitization of TRPV1 at the spinal cord may play a role in central sensitization in STZ-induced neuropathy. PMID:21794120

  4. Aging reverses the role of the transient receptor potential vanilloid-1 channel in systemic inflammation from anti-inflammatory to proinflammatory

    PubMed Central

    Wanner, Samuel P; Garami, Andras; Pakai, Eszter; Oliveira, Daniela L; Gavva, Narender R; Coimbra, Cândido C

    2012-01-01

    Studies in young rodents have shown that the transient receptor potential vanilloid-1 (TRPV1) channel plays a suppressive role in the systemic inflammatory response syndrome (SIRS) by inhibiting production of tumor necrosis factor (TNF)α and possibly by other mechanisms. We asked whether the anti-inflammatory role of TRPV1 changes with age. First, we studied the effect of AMG517, a selective and potent TRPV1 antagonist, on aseptic, lipopolysaccharide (LPS)-induced SIRS in young (12 wk) mice. In agreement with previous studies, AMG517 increased LPS-induced mortality in the young. We then studied the effects of TRPV1 antagonism (AMG517 or genetic deletion of TRPV1) on SIRS in middle-aged (43–44 wk) mice. Both types of TRPV1 antagonism delayed and decreased LPS-induced mortality, indicating a reversal of the anti-inflammatory role of TRPV1 with aging. In addition, deletion of TRPV1 decreased the serum TNFα response to LPS, suggesting that the suppressive control of TRPV1 on TNFα production is also reversed with aging. In contrast to aseptic SIRS, polymicrobial sepsis (induced by cecal ligation and puncture) caused accelerated mortality in aged TRPV1-deficient mice as compared with wild-type littermates. The recovery of TRPV1-deficient mice from hypothermia associated with the cecal ligation and puncture procedure was delayed. Hence, the reversal of the anti-inflammatory role of TRPV1 found in the aged and their decreased systemic inflammatory response are coupled with suppressed defense against microbial infection. These results caution that TRPV1 antagonists, widely viewed as new-generation painkillers, may decrease the resistance of older patients to infection and sepsis. PMID:22214765

  5. Transient receptor potential vanilloid 1 activation by dietary capsaicin promotes urinary sodium excretion by inhibiting epithelial sodium channel α subunit-mediated sodium reabsorption.

    PubMed

    Li, Li; Wang, Fei; Wei, Xing; Liang, Yi; Cui, Yuanting; Gao, Feng; Zhong, Jian; Pu, Yunfei; Zhao, Yu; Yan, Zhencheng; Arendshorst, William J; Nilius, Bernd; Chen, Jing; Liu, Daoyan; Zhu, Zhiming

    2014-08-01

    High salt (HS) intake contributes to the development of hypertension. Epithelial sodium channels play crucial roles in regulating renal sodium reabsorption and blood pressure. The renal transient receptor potential vanilloid 1 (TRPV1) cation channel can be activated by its agonist capsaicin. However, it is unknown whether dietary factors can act on urinary sodium excretion and renal epithelial sodium channel (ENaC) function. Here, we report that TRPV1 activation by dietary capsaicin increased urinary sodium excretion through reducing sodium reabsorption in wild-type (WT) mice on a HS diet but not in TRPV1(-/-) mice. The effect of capsaicin on urinary sodium excretion was involved in inhibiting αENaC and its related with-no-lysine kinase 1/serum- and glucocorticoid-inducible protein kinase 1 pathway in renal cortical collecting ducts of WT mice. Dietary capsaicin further reduced the increased αENaC activity in WT mice attributed to the HS diet. In contrast, this capsaicin effect was absent in TRPV1(-/-) mice. Immunoprecipitation study indicated αENaC specifically coexpressed and functionally interact with TRPV1 in renal cortical collecting ducts of WT mice. Additionally, ENaC activity and expression were suppressed by capsaicin-mediated TRPV1 activation in cultured M1-cortical collecting duct cells. Long-term dietary capsaicin prevented the development of high blood pressure in WT mice on a HS diet. It concludes that TRPV1 activation in the cortical collecting ducts by capsaicin increases urinary sodium excretion and avoids HS diet-induced hypertension through antagonizing αENaC-mediated urinary sodium reabsorption. Dietary capsaicin may represent a promising lifestyle intervention in populations exposed to a high dietary salt intake.

  6. Ameliorating Endothelial Mitochondrial Dysfunction Restores Coronary Function via Transient Receptor Potential Vanilloid 1-Mediated Protein Kinase A/Uncoupling Protein 2 Pathway.

    PubMed

    Xiong, Shiqiang; Wang, Peijian; Ma, Liqun; Gao, Peng; Gong, Liuping; Li, Li; Li, Qiang; Sun, Fang; Zhou, Xunmei; He, Hongbo; Chen, Jing; Yan, Zhencheng; Liu, Daoyan; Zhu, Zhiming

    2016-02-01

    Coronary heart disease arising from atherosclerosis is a leading cause of cardiogenic death worldwide. Mitochondria are the principal source of reactive oxygen species (ROS), and defective oxidative phosphorylation by the mitochondrial respiratory chain contributes to ROS generation. Uncoupling protein 2 (UCP2), an adaptive antioxidant defense factor, protects against mitochondrial ROS-induced endothelial dysfunction in atherosclerosis. The activation of transient receptor potential vanilloid 1 (TRPV1) attenuates vascular dysfunction. Therefore, whether TRPV1 activation antagonizes coronary lesions by alleviating endothelial mitochondrial dysfunction and enhancing the activity of the protein kinase A/UCP2 pathway warrants examination. ApoE(-/-), ApoE(-/-)/TRPV1(-/-), and ApoE(-/-)/UCP2(-/-) mice were fed standard chow, a high-fat diet (HFD), or the HFD plus 0.01% capsaicin. HFD intake profoundly impaired coronary vasodilatation and myocardial perfusion and shortened the survival duration of ApoE(-/-) mice. TRPV1 or UCP2 deficiency exacerbated HFD-induced coronary dysfunction and was associated with increased ROS generation and reduced nitric oxide production in the endothelium. The activation of TRPV1 by capsaicin upregulated UCP2 expression via protein kinase A phosphorylation, thereby alleviating endothelial mitochondrial dysfunction and inhibiting mitochondrial ROS generation. In vivo, dietary capsaicin supplementation enhanced coronary relaxation and prolonged the survival duration of HFD-fed ApoE(-/-) mice. These effects were not observed in ApoE(-/-) mice lacking the TRPV1 or UCP2 gene. The upregulation of protein kinase A /UCP2 via TRPV1 activation ameliorates coronary dysfunction and prolongs the lifespan of atherosclerotic mice by ameliorating endothelial mitochondrial dysfunction. Dietary capsaicin supplementation may represent a promising intervention for the primary prevention of coronary heart disease. PMID:26667415

  7. Carboxyl-terminal domain of transient receptor potential vanilloid 1 contains distinct segments differentially involved in capsaicin- and heat-induced desensitization.

    PubMed

    Joseph, John; Wang, Sen; Lee, Jongseok; Ro, Jin Y; Chung, Man-Kyo

    2013-12-13

    Multiple Ca(2+)-dependent processes are involved in capsaicin-induced desensitization of transient receptor potential vanilloid 1 (TRPV1), but desensitization of TRPV1 by heat occurs even in the absence of extracellular Ca(2+), although the mechanisms are unknown. In this study, we tested the hypothesis that capsaicin and heat desensitize TRPV1 through distinct mechanisms involving distinct structural segments of TRPV1. In HEK293 cells that heterologously express TRPV1, we found that heat-induced desensitization was not affected by the inclusion of intracellular ATP or alanine mutation of Lys(155), both of which attenuate capsaicin-induced desensitization, suggesting that heat-induced desensitization occurs through mechanisms distinct from capsaicin-induced desensitization. To determine protein domains involved in heat-induced desensitization, we generated chimeric proteins between TRPV1 and TRPV3, a heat-gated channel lacking heat-induced desensitization. We found that TRPV1 with the carboxyl-terminal domain (CTD) of TRPV3 retained heat activation but was impaired in heat-induced desensitization. Further experiments using chimeric or deletion mutants within TRPV1 CTD indicated that the distal half of CTD regulates the activation and desensitization of TRPV1 in modality-specific manners. Within the distal CTD, we identified two segments that distinctly regulated capsaicin- and heat-induced desensitization. The results suggest that the activation and desensitization of TRPV1 by capsaicin and heat can be modulated differentially and disproportionally through different regions of TRPV1 CTD. Identifying the domains involved in thermal regulation of TRPV1 may facilitate the development of novel anti-hyperalgesic approaches aimed at attenuating activation and enhancing desensitization of TRPV1 by thermal stimuli.

  8. Functionally important amino acid residues in the transient receptor potential vanilloid 1 (TRPV1) ion channel – an overview of the current mutational data

    PubMed Central

    2013-01-01

    This review aims to create an overview of the currently available results of site-directed mutagenesis studies on transient receptor potential vanilloid type 1 (TRPV1) receptor. Systematization of the vast number of data on the functionally important amino acid mutations of TRPV1 may provide a clearer picture of this field, and may promote a better understanding of the relationship between the structure and function of TRPV1. The review summarizes information on 112 unique mutated sites along the TRPV1, exchanged to multiple different residues in many cases. These mutations influence the effect or binding of different agonists, antagonists, and channel blockers, alter the responsiveness to heat, acid, and voltage dependence, affect the channel pore characteristics, and influence the regulation of the receptor function by phosphorylation, glycosylation, calmodulin, PIP2, ATP, and lipid binding. The main goal of this paper is to publish the above mentioned data in a form that facilitates in silico molecular modelling of the receptor by promoting easier establishment of boundary conditions. The better understanding of the structure-function relationship of TRPV1 may promote discovery of new, promising, more effective and safe drugs for treatment of neurogenic inflammation and pain-related diseases and may offer new opportunities for therapeutic interventions. PMID:23800232

  9. Visualization by High Resolution Immunoelectron Microscopy of the Transient Receptor Potential Vanilloid-1 at Inhibitory Synapses of the Mouse Dentate Gyrus

    PubMed Central

    Canduela, Miren-Josune; Mendizabal-Zubiaga, Juan; Puente, Nagore; Reguero, Leire; Elezgarai, Izaskun; Ramos-Uriarte, Almudena; Gerrikagoitia, Inmaculada; Grandes, Pedro

    2015-01-01

    We have recently shown that the transient receptor potential vanilloid type 1 (TRPV1), a non-selective cation channel in the peripheral and central nervous system, is localized at postsynaptic sites of the excitatory perforant path synapses in the hippocampal dentate molecular layer (ML). In the present work, we have studied the distribution of TRPV1 at inhibitory synapses in the ML. With this aim, a preembedding immunogold method for high resolution electron microscopy was applied to mouse hippocampus. About 30% of the inhibitory synapses in the ML are TRPV1 immunopositive, which is mostly localized perisynaptically (∼60% of total immunoparticles) at postsynaptic dendritic membranes receiving symmetric synapses in the inner 1/3 of the layer. This TRPV1 pattern distribution is not observed in the ML of TRPV1 knock-out mice. These findings extend the knowledge of the subcellular localization of TRPV1 to inhibitory synapses of the dentate molecular layer where the channel, in addition to excitatory synapses, is present. PMID:25775089

  10. Pharmacology and antitussive efficacy of 4-(3-trifluoromethyl-pyridin-2-yl)-piperazine-1-carboxylic acid (5-trifluoromethyl-pyridin-2-yl)-amide (JNJ17203212), a transient receptor potential vanilloid 1 antagonist in guinea pigs.

    PubMed

    Bhattacharya, Anindya; Scott, Brian P; Nasser, Nadia; Ao, Hong; Maher, Michael P; Dubin, Adrienne E; Swanson, Devin M; Shankley, Nigel P; Wickenden, Alan D; Chaplan, Sandra R

    2007-11-01

    Transient receptor potential vanilloid 1 (TRPV1) plays an integral role in modulating the cough reflex, and it is an attractive antitussive drug target. The purpose of this study was to characterize a TRPV1 antagonist, 4-(3-trifluoromethyl-pyridin-2-yl)-piperazine-1-carboxylic acid (5-trifluoromethyl-pyridin-2-yl)-amide (JNJ17203212), against the guinea pig TRPV1 receptor in vitro followed by a proof-of-principle study in an acid-induced model of cough. The affinity of JNJ17203212 for the recombinant guinea pig TRPV1 receptor was estimated by radioligand binding, and it was functionally characterized by antagonism of low-pH and capsaicin-induced activation of the ion channel (fluorometric imaging plate reader and electrophysiology). The nature of antagonism was further tested against the native channel in isolated guinea pig tracheal rings. Following pharmacokinetic characterization of JNJ17203212 in guinea pigs, pharmacodynamic and efficacy studies were undertaken to establish the antitussive efficacy of the TRPV1 antagonist. The pK(i) of JNJ17203212 for recombinant guinea pig TRPV1 was 7.14 +/- 0.06. JNJ17203212 inhibited both pH (pIC(50) of 7.23 +/- 0.05) and capsaicin (pIC(50) of 6.32 +/- 0.06)-induced channel activation. In whole-cell patch clamp, the pIC(50) for inhibition of guinea pig TRPV1 was 7.3 +/- 0.01. JNJ17203212 demonstrated surmountable antagonism in isolated trachea, with a pK(B) value of 6.2 +/- 0.1. Intraperitoneal administration of 20 mg/kg JNJ17203212 achieved a maximal plasma exposure of 8.0 +/- 0.4 microM, and it attenuated capsaicin evoked coughs with similar efficacy to codeine (25 mg/kg). Last, JNJ17203212 dose-dependently produced antitussive efficacy in citric acid-induced experimental cough in guinea pigs. Our data provide preclinical support for developing TRPV1 antagonists for the treatment of cough.

  11. Non-vanillyl resiniferatoxin analogues as potent and metabolically stable transient receptor potential vanilloid 1 agonists

    PubMed Central

    Choi, Hyun-Kyung; Choi, Sun; Lee, Yoonji; Kang, Dong Wook; Ryu, HyungChul; Maeng, Han-Joo; Chung, Suk-Jae; Pavlyukovets, Vladimir A.; Pearce, Larry V.; Toth, Attila; Tran, Richard; Wang, Yun; Morgan, Matthew A.; Blumberg, Peter M.; Lee, Jeewoo

    2009-01-01

    A series of non-vanillyl resiniferatoxin analogues, having 4-methylsulfonylaminophenyl and fluorophenyl moieties as vanillyl surrogates, have been investigated as ligands for rat TRPV1 heterologously expressed in Chinese hamster ovary cells. Although lacking the metabolically problematic 4-hydroxy substituent on the A-region phenyl ring, the compounds retained substantial agonist potency. Indeed, the 3-methoxy-4-methylsulfonylaminophenyl analog (1) was modestly (2.5-fold) more potent than RTX, with an EC50 = 0.106 nM. Further, it resembled RTX in its kinetics and pattern of stimulation of the levels of intracellular calcium in individual cells, as revealed by imaging. Compound 1 displayed modestly enhanced in vitro stability in rat liver microsomes and in plasma, suggesting that it might be a pharmacokinetically more favorable surrogate of resiniferatoxin. Molecular modeling analyses with selected analogues provide evidence that the conformational differences could affect their binding affinities, especially for the ester versus amide at the B-region. PMID:19135377

  12. Synthesis of Analogues of BCTC Incorporating a Pyrrolidinyl Linker and Biological Evaluation as Transient Receptor Potential Vanilloid 1 Antagonists.

    PubMed

    Yan, Lin; Wang, Jingjie; Pan, Miaobo; Qiu, Qianqian; Huang, Wenlong; Qian, Hai

    2016-02-01

    A series of novel pyrrolidinyl linker TRPV1 antagonists were prepared in an effort to lower the hyperthermic side-effects of first-generation antagonist BCTC. These compounds were investigated for antagonism of hTRPV1 activation by capsaicin and acid in vitro. Preliminary results suggested the compounds 10a, 10b, 10c and 10j had favorable TRPV1 antagonism activity. In further studies in vivo, 10b, comparable to BCTC, showed potent analgesic activity in capsaicin-induced and heat-induced pain models. In addition, 10b indicated a reduced risk of body temperature elevation. All of these demonstrated that 10b can be considered as a safe candidate for the further development of analgesic drugs.

  13. Transient Receptor Potential Channel Polymorphisms Are Associated with the Somatosensory Function in Neuropathic Pain Patients

    PubMed Central

    Baron, Ralf; Maier, Christoph; Tölle, Thomas R.; Treede, Rolf-Detlef; Berthele, Achim; Faltraco, Frank; Flor, Herta; Gierthmühlen, Janne; Haenisch, Sierk; Huge, Volker; Magerl, Walter; Maihöfner, Christian; Richter, Helmut; Rolke, Roman; Scherens, Andrea; Üçeyler, Nurcan; Ufer, Mike; Wasner, Gunnar; Zhu, Jihong; Cascorbi, Ingolf

    2011-01-01

    Transient receptor potential channels are important mediators of thermal and mechanical stimuli and play an important role in neuropathic pain. The contribution of hereditary variants in the genes of transient receptor potential channels to neuropathic pain is unknown. We investigated the frequency of transient receptor potential ankyrin 1, transient receptor potential melastin 8 and transient receptor potential vanilloid 1 single nucleotide polymorphisms and their impact on somatosensory abnormalities in neuropathic pain patients. Within the German Research Network on Neuropathic Pain (Deutscher Forscbungsverbund Neuropathischer Schmerz) 371 neuropathic pain patients were phenotypically characterized using standardized quantitative sensory testing. Pyrosequencing was employed to determine a total of eleven single nucleotide polymorphisms in transient receptor potential channel genes of the neuropathic pain patients and a cohort of 253 German healthy volunteers. Associations of quantitative sensory testing parameters and single nucleotide polymorphisms between and within groups and subgroups, based on sensory phenotypes, were analyzed. Single nucleotide polymorphisms frequencies did not differ between both the cohorts. However, in neuropathic pain patients transient receptor potential ankyrin 1 710G>A (rs920829, E179K) was associated with the presence of paradoxical heat sensation (p = 0.03), and transient receptor potential vanilloid 1 1911A>G (rs8065080, I585V) with cold hypoalgesia (p = 0.0035). Two main subgroups characterized by preserved (1) and impaired (2) sensory function were identified. In subgroup 1 transient receptor potential vanilloid 1 1911A>G led to significantly less heat hyperalgesia, pinprick hyperalgesia and mechanical hypaesthesia (p = 0.006, p = 0.005 and p<0.001) and transient receptor potential vanilloid 1 1103C>G (rs222747, M315I) to cold hypaesthesia (p = 0.002), but there was absence of associations in subgroup 2. In

  14. Changes in Gene Expression Patterns of Circadian-Clock, Transient Receptor Potential Vanilloid-1 and Nerve Growth Factor in Inflamed Human Esophagus

    PubMed Central

    Yang, Shu-Chuan; Chen, Chien-Lin; Yi, Chih-Hsun; Liu, Tso-Tsai; Shieh, Kun-Ruey

    2015-01-01

    Circadian rhythm is driven by the molecular circadian-clock system and regulates many physiological functions. Diurnal rhythms in the gastrointestinal tract are known to be related to feeding pattern, but whether these rhythms are also related to the gastrointestinal damage or injuries; for example, gastroesophageal reflux disease (GERD), is unclear. This study was conducted to determine whether expression of circadian-clock genes or factors involved in vagal stimulation or sensitization were altered in the esophagus of GERD patients. Diurnal patterns of PER1, PER2, BMAL1, CRY2, TRPV1, and NGF mRNA expression were found in patient controls, and these patterns were altered and significantly correlated to the GERD severity in GERD patients. Although levels of CRY1, TIM, CB1, NHE3, GDNF, and TAC1 mRNA expression did not show diurnal patterns, they were elevated and also correlated with GERD severity in GERD patients. Finally, strong correlations among PER1, TRPV1, NGF and CRY2 mRNA expression, and among PER2, TRPV1 and CRY2 expression were found. Expression levels of CRY1 mRNA highly correlated with levels of TIM, CB1, NHE3, GDNF and TAC1. This study suggests that the circadian rhythm in the esophagus may be important for the mediation of and/or the response to erosive damage in GERD patients. PMID:26337663

  15. Benzo[d]imidazole Transient Receptor Potential Vanilloid 1 Antagonists for the Treatment of Pain: Discovery of trans-2-(2-{2-[2-(4-Trifluoromethyl-phenyl)-vinyl]-1H-benzimidazol-5-yl}-phenyl)-propan-2-ol (Mavatrep).

    PubMed

    Parsons, William H; Calvo, Raul R; Cheung, Wing; Lee, Yu-Kai; Patel, Sharmila; Liu, Jian; Youngman, Mark A; Dax, Scott L; Stone, Dennis; Qin, Ning; Hutchinson, Tasha; Lubin, Mary Lou; Zhang, Sui-Po; Finley, Michael; Liu, Yi; Brandt, Michael R; Flores, Christopher M; Player, Mark R

    2015-05-14

    Reported herein is the design, synthesis, and pharmacologic characterization of a class of TRPV1 antagonists constructed on a benzo[d]imidazole platform that evolved from a biaryl amide lead. This design composes three sections: a 2-substituted 5-phenyl headgroup attached to the benzo[d]imidazole platform, which is tethered at the two position to a phenyl tail group. Optimization of this design led to the identification of 4 (mavatrep), comprising a trifluoromethyl-phenyl-vinyl tail. In a TRPV1 functional assay, using cells expressing recombinant human TRPV1 channels, 4 antagonized capsaicin-induced Ca(2+) influx, with an IC50 value of 4.6 nM. In the complete Freund's adjuvant- and carrageenan-induced thermal hypersensitivity models, 4 exhibited full efficacy, with ED80 values of 7.8 and 0.5 mg/kg, respectively, corresponding to plasma levels of 270.8 and 9.2 ng/mL, respectively. On the basis of its superior pharmacologic and safety profile, 4 (mavatrep) was selected for clinical development for the treatment of pain. PMID:25850459

  16. [Considerations about study on mechanisms of thermal efficacies of moxibustion from activities of transient receptor potential family].

    PubMed

    Lu, Sheng-Feng; Yin, Hai-Yan; Tang, Yong; Zhang, Cheng-Shun; Yu, Mei-Ling; Luo, Ling; Yu, Shu-Guang

    2012-04-01

    Of the mammalian transient receptor potential (TRP) superfamily members, transient receptor potential vanilloid 1 (TRPV 1), TRPV 2,TRPV 3,TRPV 4,melastatin transient receptor potential (TRPM) 4, TRPM 5, and TRP ankyrin 1 (TRPA 1), are mostly permeable to both monovalent and divalent cation channels and are able to sense to changes of the temperature. Cutaneous TRPV 1, TRPV 2, TRPV 3, TRPV 4, TRPM 4 and TRPM 5 are sensitive to warm stimulation. Moxibustion, a type of physical thermal stimulus, can bring forth some curative effects after applying to certain acupoints for a period of time. Therefore, it is possible to reveal the underlying mechanisms of moxibustion in improving some related clinical disorders through studying activities of transient receptor potential family members. In the present paper, the authors summarize various characteristics of the activated TRP family members in the cutaneous tissue. Moreover, the authors also put forward some researching ideas about the local triggering mechanism of moxibustion stimulation and the resultant cascading effects by combining with its characters of local special responses in experimental studies.

  17. Activation characteristics of transient receptor potential ankyrin 1 and its role in nociception.

    PubMed

    Raisinghani, Manish; Zhong, Linlin; Jeffry, Joseph A; Bishnoi, Mahendra; Pabbidi, Reddy M; Pimentel, Fátima; Cao, De-Shou; Evans, M Steven; Premkumar, Louis S

    2011-09-01

    Transient receptor potential (TRP) ankyrin 1 (TRPA1) is a Ca(2+)-permeant, nonselective cationic channel. It is predominantly expressed in the C afferent sensory nerve fibers of trigeminal and dorsal root ganglion neurons and is highly coexpressed with the nociceptive ion channel transient receptor potential vanilloid 1 (TRPV1). Several physical and chemical stimuli have been shown to activate the channel. In this study, we have used electrophysiological techniques and behavioral models to characterize the properties of TRPA1. Whole cell TRPA1 currents induced by brief application of lower concentrations of N-methyl maleimide (NMM) or allyl isothiocyanate (AITC) can be reversed readily by washout, whereas continuous application of higher concentrations of NMM or AITC completely desensitized the currents. The deactivation and desensitization kinetics differed between NMM and AITC. TRPA1 current amplitude increased with repeated application of lower concentrations of AITC, whereas saturating concentrations of AITC induced tachyphylaxis, which was more pronounced in the presence of extracellular Ca(2+). The outward rectification exhibited by native TRPA1-mediated whole cell and single-channel currents was minimal as compared with other TRP channels. TRPA1 currents were negatively modulated by protons and polyamines, both of which activate the heat-sensitive channel, TRPV1. Interestingly, neither protein kinase C nor protein kinase A activation sensitized AITC-induced currents, but each profoundly sensitized capsaicin-induced currents. Current-clamp experiments revealed that AITC produced a slow and sustained depolarization as compared with capsaicin. TRPA1 is also expressed at the central terminals of nociceptors at the caudal spinal trigeminal nucleus. Activation of TRPA1 in this area increases the frequency and amplitude of miniature excitatory or inhibitory postsynaptic currents. In behavioral studies, intraplantar and intrathecal administration of AITC induced

  18. Structural determinants of the transient receptor potential 1 (TRPV1) channel activation by phospholipid analogs.

    PubMed

    Morales-Lázaro, Sara L; Serrano-Flores, Barbara; Llorente, Itzel; Hernández-García, Enrique; González-Ramírez, Ricardo; Banerjee, Souvik; Miller, Duane; Gududuru, Veeresh; Fells, James; Norman, Derek; Tigyi, Gabor; Escalante-Alcalde, Diana; Rosenbaum, Tamara

    2014-08-29

    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal protein that responds to various stimuli, including capsaicin (the pungent compound found in chili peppers), extracellular acid, and basic intracellular pH, temperatures close to 42 °C, and several lipids. Lysophosphatidic acid (LPA), an endogenous lipid widely associated with neuropathic pain, is an agonist of the TRPV1 channel found in primary afferent nociceptors and is activated by other noxious stimuli. Agonists or antagonists of lipid and other chemical natures are known to possess specific structural requirements for producing functional effects on their targets. To better understand how LPA and other lipid analogs might interact and affect the function of TRPV1, we set out to determine the structural features of these lipids that result in the activation of TRPV1. By changing the acyl chain length, saturation, and headgroup of these LPA analogs, we established strict requirements for activation of TRPV1. Among the natural LPA analogs, we found that only LPA 18:1, alkylglycerophosphate 18:1, and cyclic phosphatidic acid 18:1, all with a monounsaturated C18 hydrocarbon chain activate TRPV1, whereas polyunsaturated and saturated analogs do not. Thus, TRPV1 shows a more restricted ligand specificity compared with LPA G-protein-coupled receptors. We synthesized fatty alcohol phosphates and thiophosphates and found that many of them with a single double bond in position Δ9, 10, or 11 and Δ9 cyclopropyl group can activate TRPV1 with efficacy similar to capsaicin. Finally, we developed a pharmacophore and proposed a mechanistic model for how these lipids could induce a conformational change that activates TRPV1. PMID:25035428

  19. Structural Determinants of the Transient Receptor Potential 1 (TRPV1) Channel Activation by Phospholipid Analogs*

    PubMed Central

    Morales-Lázaro, Sara L.; Serrano-Flores, Barbara; Llorente, Itzel; Hernández-García, Enrique; González-Ramírez, Ricardo; Banerjee, Souvik; Miller, Duane; Gududuru, Veeresh; Fells, James; Norman, Derek; Tigyi, Gabor; Escalante-Alcalde, Diana; Rosenbaum, Tamara

    2014-01-01

    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal protein that responds to various stimuli, including capsaicin (the pungent compound found in chili peppers), extracellular acid, and basic intracellular pH, temperatures close to 42 °C, and several lipids. Lysophosphatidic acid (LPA), an endogenous lipid widely associated with neuropathic pain, is an agonist of the TRPV1 channel found in primary afferent nociceptors and is activated by other noxious stimuli. Agonists or antagonists of lipid and other chemical natures are known to possess specific structural requirements for producing functional effects on their targets. To better understand how LPA and other lipid analogs might interact and affect the function of TRPV1, we set out to determine the structural features of these lipids that result in the activation of TRPV1. By changing the acyl chain length, saturation, and headgroup of these LPA analogs, we established strict requirements for activation of TRPV1. Among the natural LPA analogs, we found that only LPA 18:1, alkylglycerophosphate 18:1, and cyclic phosphatidic acid 18:1, all with a monounsaturated C18 hydrocarbon chain activate TRPV1, whereas polyunsaturated and saturated analogs do not. Thus, TRPV1 shows a more restricted ligand specificity compared with LPA G-protein-coupled receptors. We synthesized fatty alcohol phosphates and thiophosphates and found that many of them with a single double bond in position Δ9, 10, or 11 and Δ9 cyclopropyl group can activate TRPV1 with efficacy similar to capsaicin. Finally, we developed a pharmacophore and proposed a mechanistic model for how these lipids could induce a conformational change that activates TRPV1. PMID:25035428

  20. Structural determinants of the transient receptor potential 1 (TRPV1) channel activation by phospholipid analogs.

    PubMed

    Morales-Lázaro, Sara L; Serrano-Flores, Barbara; Llorente, Itzel; Hernández-García, Enrique; González-Ramírez, Ricardo; Banerjee, Souvik; Miller, Duane; Gududuru, Veeresh; Fells, James; Norman, Derek; Tigyi, Gabor; Escalante-Alcalde, Diana; Rosenbaum, Tamara

    2014-08-29

    The transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal protein that responds to various stimuli, including capsaicin (the pungent compound found in chili peppers), extracellular acid, and basic intracellular pH, temperatures close to 42 °C, and several lipids. Lysophosphatidic acid (LPA), an endogenous lipid widely associated with neuropathic pain, is an agonist of the TRPV1 channel found in primary afferent nociceptors and is activated by other noxious stimuli. Agonists or antagonists of lipid and other chemical natures are known to possess specific structural requirements for producing functional effects on their targets. To better understand how LPA and other lipid analogs might interact and affect the function of TRPV1, we set out to determine the structural features of these lipids that result in the activation of TRPV1. By changing the acyl chain length, saturation, and headgroup of these LPA analogs, we established strict requirements for activation of TRPV1. Among the natural LPA analogs, we found that only LPA 18:1, alkylglycerophosphate 18:1, and cyclic phosphatidic acid 18:1, all with a monounsaturated C18 hydrocarbon chain activate TRPV1, whereas polyunsaturated and saturated analogs do not. Thus, TRPV1 shows a more restricted ligand specificity compared with LPA G-protein-coupled receptors. We synthesized fatty alcohol phosphates and thiophosphates and found that many of them with a single double bond in position Δ9, 10, or 11 and Δ9 cyclopropyl group can activate TRPV1 with efficacy similar to capsaicin. Finally, we developed a pharmacophore and proposed a mechanistic model for how these lipids could induce a conformational change that activates TRPV1.

  1. Activation of transient receptor potential A1 by a non-pungent capsaicin-like compound, capsiate

    PubMed Central

    Shintaku, Kenji; Uchida, Kunitoshi; Suzuki, Yoshiro; Zhou, Yiming; Fushiki, Tohru; Watanabe, Tatsuo; Yazawa, Susumu; Tominaga, Makoto

    2012-01-01

    BACKGROUND AND PURPOSE Capsiate is produced by ‘CH-19 Sweet’ (Capsicum annuun L.), a non-pungent cultivar of red pepper. Like capsaicin, capsiate is thought to enhance energy metabolism by activating the sympathetic nervous system and suppressing inflammation, but the underlying mechanisms for this are uncertain. We previously reported that capsiate could activate transient receptor potential vanilloid 1 (TRPV1), a capsaicin receptor. The purpose of the present study is to investigate whether capsinoids activate other TRP channels. EXPERIMENTAL APPROACH Using Ca2+ imaging and whole-cell patch-clamp methods, we analysed the response of TRP channels to three kinds of capsinoids, capsiate, dihydrocapsiate and nordihydrocapsiate, in HEK293T cells expressing TRP channels or in primary cultures of mouse dorsal root ganglion neurons. KEY RESULTS We found that in both cell types TRP ankyrin 1 (TRPA1) had a slightly weaker response to capsinoids compared with TRPV1, with the capsiate EC50 for TRPA1 activation being more than that for TRPV1 activation, and that the capsinoid-evoked action was blocked by a specific TRPA1 antagonist. TRPA1 was activated by capsinoids, but not by their degradation products. Amino acids known to participate in TRPA1 activation following cysteine covalent modification or zinc treatment were not involved in the activation of TRPA1 by capsinoid. CONCLUSIONS AND IMPLICATIONS Taken together, these results indicate that capsinoids activate TRPA1 by an as yet unknown mechanism, and TRPA1 could be involved in physiological phenomena associated with capsinoid treatment. PMID:21883144

  2. Osmoregulatory thirst in mice lacking the transient receptor potential vanilloid type 1 (TRPV1) and/or type 4 (TRPV4) receptor.

    PubMed

    Kinsman, Brian; Cowles, James; Lay, Jennifer; Simmonds, Sarah S; Browning, Kirsteen N; Stocker, Sean D

    2014-11-01

    Recent studies suggest the ability of the central nervous system to detect changes in osmolality is mediated by products of the genes encoding the transient receptor potential vanilloid-1 (TRPV1) or vanilloid-4 (TRPV4) channel. The purpose of the present study was to determine whether deletion of TRPV1 and/or TRPV4 channels altered thirst responses to cellular dehydration in mice. Injection of 0.5 or 1.0 M NaCl produced dose-dependent increases in cumulative water intakes of wild-type (WT), TRPV1-/-, TRPV4-/-, and TRPV1-/-V4-/- mice. However, there were no differences in cumulative water intakes between WT versus any other strain despite similar increases in plasma electrolytes and osmolality. Similar results were observed after injection of hypertonic mannitol. This was a consistent finding regardless of the injection route (intraperitoneal vs. subcutaneous) or timed access to water (delayed vs. immediate). There were also no differences in cumulative intakes across strains after injection of 0.15 M NaCl or during a time-controlled period (no injection). Chronic hypernatremia produced by sole access to 2% NaCl for 48 h also produced similar increases in water intake across strains. In a final set of experiments, subcutaneous injection of 0.5 M NaCl produced similar increases in the number of Fos-positive nuclei within the organum vasculosum of the lamina terminalis and median preoptic nucleus across strains but significantly smaller number in the subfornical organ of WT versus TRPV1-/-V4-/- mice. Collectively, these findings suggest that TRPV1 and/or TRPV4 channels are not the primary mechanism by which the central nervous system responds to cellular dehydration during hypernatremia or hyperosmolality to increase thirst.

  3. The blockade of transient receptor potential ankirin 1 (TRPA1) signalling mediates antidepressant- and anxiolytic-like actions in mice

    PubMed Central

    de Moura, Juliana Cavalcante; Noroes, Maíra Macedo; Rachetti, Vanessa de Paula Soares; Soares, Bruno Lobão; Preti, Delia; Nassini, Romina; Materazzi, Serena; Marone, Ilaria Maddalena; Minocci, Daiana; Geppetti, Pierangelo; Gavioli, Elaine Cristina; André, Eunice

    2014-01-01

    Background and Purpose Transient receptor potential vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) are involved in many biological processes, including nociception and hyperalgesia. Whereas the involvement of TRPV1 in psychiatric disorders such as anxiety and depression has been reported, little is known regarding the role of TRPA1 in these conditions. Experimental Approach We investigated the role of TRPA1 in mice models of depression [forced swimming test (FST)] and anxiety [elevated plus maze (EPM) test]. Key Results Administration of the TRPA1 antagonist (HC030031, 30 nmol in 2 μL, i.c.v.) reduced immobility time in the FST. Similar results were obtained after oral administration of HC030031 (30–300 mg·kg−1). The reduction in immobility time in FST induced by HC030031 (100 mg·kg−1) was completely prevented by pretreatment with TRPA1 agonist, cinnamaldehyde (50 mg·kg−1, p.o.), which per se was inactive. In the EPM test, pretreatment with cinnamaldehyde (50 mg·kg−1, p.o.), which per se did not affect behaviour response, prevented the anxiolytic-like effect (increased open arm exploration) evoked by TRPA1 blockade (HC030031, 100 mg·kg−1, p.o.). Treatment with either cinnamaldehyde or HC030031 did not affect spontaneous ambulation. Furthermore, TRPA1-deficient mice showed anxiolytic- and antidepressant-like phenotypes in the FST and EPM test respectively. Conclusion and Implications The present findings indicate that genetic deletion or pharmacological blockade of TRPA1 produces inhibitory activity in mouse models of anxiety and depression. These results imply that TRPA1 exerts tonic control, promoting anxiety and depression, and that TRPA1 antagonism has potential as an innovative strategy for the treatment of anxiety and mood disorders. PMID:24846744

  4. 3-Iodothyronamine increases transient receptor potential melastatin channel 8 (TRPM8) activity in immortalized human corneal epithelial cells.

    PubMed

    Lucius, Alexander; Khajavi, Noushafarin; Reinach, Peter S; Köhrle, Josef; Dhandapani, Priyavathi; Huimann, Philipp; Ljubojevic, Nina; Grötzinger, Carsten; Mergler, Stefan

    2016-03-01

    3-Iodothyronamine (3T1AM) is an endogenous thyroid hormone metabolite that interacts with the human trace amine-associated receptor 1 (hTAAR1), a G-protein-coupled receptor, to induce numerous physiological responses including dose-dependent body temperature lowering in rodents. 3T1AM also directly activates cold-sensitive transient receptor potential melastatin 8 (TRPM8) channels in human conjunctival epithelial cells (HCjEC) at constant temperature as well as reducing rises in IL-6 release induced by transient receptor potential vanilloid 1 (TRPV1) activation by capsaicin (CAP). Here, we describe that 3T1AM-induced TRPM8 activation suppresses through crosstalk TRPV1 activation in immortalized human corneal epithelial cells (HCEC). RT-PCR and immunofluorescent staining identified TRPM8 gene and protein expression. Increases in Ca(2+) influx induced by the TRPM8 agonists either 3T1AM (0.1-10 μM), menthol (500 μM), icilin (15-60 μM) or temperature lowering (either <17°C or >17°C) were all blocked by 10-20 μM BCTC, a mixed TRPV1/TRPM8 antagonist. BCTC blocked 3T1AM-induced recombinant TRPM8 activation of Ca(2+) transients in an osteosarcoma heterologous expression system. The effects of BCTC in HCEC were attributable to selective TRPM8 inhibition since whole-cell patch-clamp currents underlying Ca(2+) rises induced by 20 μM CAP were BCTC insensitive. On the other hand, Ca(2+) transients induced by activating TRPV1 with either CAP or a hyperosmolar medium were suppressed during exposure to either 1 μM 3T1AM or 15 μM icilin. All of these modulatory effects on intracellular Ca(2+) regulation induced by the aforementioned agents were attributable to changes in underlying inward and outward current. Taken together, TRPM8 activation by 3T1AM markedly attenuates and even eliminates hyperosmolar and CAP induced TRPV1 activation through crosstalk.

  5. Discovery of (R)-1-(7-chloro-2,2-bis(fluoromethyl)chroman-4-yl)-3-(3-methylisoquinolin-5-yl)urea (A-1165442): a temperature-neutral transient receptor potential vanilloid-1 (TRPV1) antagonist with analgesic efficacy.

    PubMed

    Voight, Eric A; Gomtsyan, Arthur R; Daanen, Jerome F; Perner, Richard J; Schmidt, Robert G; Bayburt, Erol K; DiDomenico, Stanley; McDonald, Heath A; Puttfarcken, Pamela S; Chen, Jun; Neelands, Torben R; Bianchi, Bruce R; Han, Ping; Reilly, Regina M; Franklin, Pamela H; Segreti, Jason A; Nelson, Richard A; Su, Zhi; King, Andrew J; Polakowski, James S; Baker, Scott J; Gauvin, Donna M; Lewis, LaGeisha R; Mikusa, Joseph P; Joshi, Shailen K; Faltynek, Connie R; Kym, Philip R; Kort, Michael E

    2014-09-11

    The synthesis and characterization of a series of selective, orally bioavailable 1-(chroman-4-yl)urea TRPV1 antagonists is described. Whereas first-generation antagonists that inhibit all modes of TRPV1 activation can elicit hyperthermia, the compounds disclosed herein do not elevate core body temperature in preclinical models and only partially block acid activation of TRPV1. Advancing the SAR of this series led to the eventual identification of (R)-1-(7-chloro-2,2-bis(fluoromethyl)chroman-4-yl)-3-(3-methylisoquinolin-5-yl)urea (A-1165442, 52), an analogue that possesses excellent pharmacological selectivity, has a favorable pharmacokinetic profile, and demonstrates good efficacy against osteoarthritis pain in rodents.

  6. Hot receptors in the brain

    PubMed Central

    Steenland, Hendrik W; Ko, Shanelle W; Wu, Long-Jun; Zhuo, Min

    2006-01-01

    Two major approaches have been employed for the development of novel drugs to treat chronic pain. The most traditional approach identifies molecules involved in pain as potential therapeutic targets and has focused mainly on the periphery and spinal cord. A more recent approach identifies molecules that are involved in long-term plasticity. Drugs developed through the latter approach are predicted to treat chronic, but not physiological or acute, pain. The TRPV1 (transient receptor potential vanilloid-1) receptor is involved in nociceptive processing, and is a candidate therapeutic target for pain. While most research on TRPV1 receptors has been conducted at the level of the spinal cord and peripheral structures, considerably less research has focused on supraspinal structures. This short paper summarizes progress made on TRPV1 receptors, and reviews research on the expression and function of TRPV1 receptors in supraspinal structures. We suggest that the TRPV1 receptor may be involved in pain processing in higher brain structures, such as the anterior cingulate cortex. In addition, some regions of the brain utilize the TRPV1 receptor for functions apparently unrelated to pain. PMID:17092351

  7. Upregulation of the Transient Receptor Potential Ankyrin 1 Ion Channel in the Inflamed Human and Mouse Colon and Its Protective Roles

    PubMed Central

    Kun, József; Szitter, István; Kemény, Ágnes; Perkecz, Anikó; Kereskai, László; Pohóczky, Krisztina; Vincze, Áron; Gódi, Szilárd; Szabó, Imre; Szolcsányi, János

    2014-01-01

    Transient Receptor Potential Ankyrin 1 (TRPA1) channels are localized on sensory nerves and several non-neural cells, but data on their functional significance are contradictory. We analysed the presence and alterations of TRPA1 in comparison with TRP Vanilloid 1 (TRPV1) at mRNA and protein levels in human and mouse intact and inflamed colons. The role of TRPA1 in a colitis model was investigated using gene-deficient mice. TRPA1 and TRPV1 expressions were investigated in human colon biopsies of healthy subjects and patients with inflammatory bowel diseases (IBD: ulcerative colitis, Crohn's disease) with quantitative PCR and immunohistochemistry. Mouse colitis was induced by oral 2% dextran-sulphate (DSS) for 10 days. For investigating the functions of TRPA1, Disease Activity Index (weight loss, stool consistency, blood content) was determined in C57BL/6-based Trpa1-deficient (knockout: KO) and wildtype (WT) mice. Sensory neuropeptides, their receptors, and inflammatory cytokines/chemokines were determined with qPCR or Luminex. In human and mouse colons TRPA1 and TRPV1 are located on epithelial cells, macrophages, enteric ganglia. Significant upregulation of TRPA1 mRNA was detected in inflamed samples. In Trpa1 KO mice, Disease Activity Index was significantly higher compared to WTs. It could be explained by the greater levels of substance P, neurokinins A and B, neurokinin 1 receptor, pituitary adenylate-cyclase activating polypeptide, vasoactive intestinal polypeptide, and also interleukin-1beta, macrophage chemoattractant protein-1, monokine induced by gamma interferon-1, tumor necrosis factor-alpha and B-lymphocyte chemoattractant in the distal colon. TRPA1 is upregulated in colitis and its activation exerts protective roles by decreasing the expressions of several proinflammatory neuropeptides, cytokines and chemokines. PMID:25265225

  8. Targeting melanocortin receptors as potential novel therapeutics.

    PubMed

    Getting, Stephen J

    2006-07-01

    Adrenocorticotrophic hormone (ACTH(1-39)) and the melanocortins (alpha, beta and gamma-melanocyte-stimulating hormone [MSH]) are derived from a larger precursor molecule known as the pro-opiomelanocortin (POMC) protein. They exert their numerous biological effects by activating 7 transmembrane G-protein coupled receptors (GPCR), leading to adenylyl cyclase activation and subsequent cAMP accumulation within the target cell. To date, 5 melanocortin receptors (MCR) have been identified and termed MC1R to MC5R, they have been shown to have a wide and varied distribution throughout the body, being found in the central nervous system (CNS), periphery and immune cells. Melanocortins have a multitude of actions including: (i) modulating disease pathologies including arthritis, asthma, obesity; (ii) affecting functions, for example erectile dysfunction, skin tanning; and (iii) organ systems, for example cardiovascular system. Recently a mechanistic approach has been identified with alpha-MSH preventing NF-kappaB activation via the preservation and expression of IkappaBalphaprotein. This leads to a reduction of pro-inflammatory mediators including cytokines and inhibition of adhesion molecule expression, with subsequent reduction in leukocyte emigration. Development of selective ligands with an appropriate pharmacokinetic profile will enable a pharmacological evaluation of the potential beneficial effects of the melanocortins. In this review I have discussed the potential mechanistic action for the melanocortins and some of the disease pathologies shown to be modulated. This review proposes targeting the MCR with the ultimate aim of controlling many of the diseases that we face today.

  9. Transient Receptor Potential Channels in the Vasculature

    PubMed Central

    Earley, Scott; Brayden, Joseph E.

    2015-01-01

    The mammalian genome encodes 28 distinct members of the transient receptor potential (TRP) superfamily of cation channels, which exhibit varying degrees of selectivity for different ionic species. Multiple TRP channels are present in all cells and are involved in diverse aspects of cellular function, including sensory perception and signal transduction. Notably, TRP channels are involved in regulating vascular function and pathophysiology, the focus of this review. TRP channels in vascular smooth muscle cells participate in regulating contractility and proliferation, whereas endothelial TRP channel activity is an important contributor to endothelium-dependent vasodilation, vascular wall permeability, and angiogenesis. TRP channels are also present in perivascular sensory neurons and astrocytic endfeet proximal to cerebral arterioles, where they participate in the regulation of vascular tone. Almost all of these functions are mediated by changes in global intracellular Ca2+ levels or subcellular Ca2+ signaling events. In addition to directly mediating Ca2+ entry, TRP channels influence intracellular Ca2+ dynamics through membrane depolarization associated with the influx of cations or through receptor- or store-operated mechanisms. Dysregulation of TRP channels is associated with vascular-related pathologies, including hypertension, neointimal injury, ischemia-reperfusion injury, pulmonary edema, and neurogenic inflammation. In this review, we briefly consider general aspects of TRP channel biology and provide an in-depth discussion of the functions of TRP channels in vascular smooth muscle cells, endothelial cells, and perivascular cells under normal and pathophysiological conditions. PMID:25834234

  10. Evidence for the role of lipid rafts and sphingomyelin in Ca2+-gating of Transient Receptor Potential channels in trigeminal sensory neurons and peripheral nerve terminals.

    PubMed

    Sághy, Éva; Szőke, Éva; Payrits, Maja; Helyes, Zsuzsanna; Börzsei, Rita; Erostyák, János; Jánosi, Tibor Zoltán; Sétáló, György; Szolcsányi, János

    2015-10-01

    Transient Receptor Potential (TRP) cation channels, such as TRP Vanilloid 1 and TRP Ankyrin repeat domain 1 (TRPV1 and TRPA1) are nocisensors playing important role to signal pain. Two "melastatin" TRP receptors, like TRPM8 and TRPM3 are also expressed in a subgroup of primary sensory neurons. These channels serve as thermosensors with unique thermal sensitivity ranges and are activated also by several exogenous and endogenous chemical ligands inducing conformational changes from various allosteric ("multisteric") sites. We analysed the role of plasma membrane microdomains of lipid rafts on isolated trigeminal (TRG) neurons and TRPV1-expressing CHO cell line by measuring agonist-induced Ca2+ transients with ratiometric technique. Stimulation-evoked calcitonin gene related peptide (CGRP) release from sensory nerve endings of the isolated rat trachea by radioimmunoassay was also measured. Lipid rafts were disrupted by cleaving sphingomyelin (SM) with sphingomyelinase (SMase), cholesterol depletion with methyl β-cyclodextrin (MCD) and ganglioside breakdown with myriocin. It has been revealed that intracellular Ca2+ increase responses evoked by the TRPV1 agonist capsaicin, the TRPA1 agonsits allyl isothiocyanate (AITC) and formaldehyde as well as the TRPM8 activator icilin were inhibited after SMase, MCD and myriocin incubation but the response to the TRPM3 agonist pregnenolon sulphate was not altered. Extracellular SMase treatment did not influence the thapsigargin-evoked Ca2+-release from intracellular stores. Besides the cell bodies, SMase also inhibited capsaicin- or AITC-evoked CGRP release from peripheral sensory nerve terminals, this provides the first evidence for the importance of lipid raft integrity in TRPV1 and TRPA1 gating on capsaicin-sensitive nerve terminals. SM metabolites, ceramide and sphingosine, did not influence TRPA1 and TRPV1 activation on TRG neurons, TRPV1-expressing CHO cell line, and nerve terminals. We suggest, that the hydrophobic

  11. Potentiation of the ionotropic GABA receptor response by whiskey fragrance.

    PubMed

    Hossain, Sheikh Julfikar; Aoshima, Hitoshi; Koda, Hirofumi; Kiso, Yoshinobu

    2002-11-01

    It is well-known that the target of most mood-defining compounds is an ionotropic gamma-aminobutyric acid receptor (GABA(A) receptor). The potentiation of the response of these inhibitory neurotransmitter receptors induces anxiolytic, sedative, and anesthetic activity in the human brain. To study the effects of whiskey fragrance on the GABA(A) receptor-mediated response, GABA(A) receptors were expressed in Xenopus oocyte by injecting rat whole brain mRNA or cRNA prepared from the cloned cDNA for the alpha(1) and beta(1) subunits of the bovine receptors. Most whiskey components such as phenol, ethoxy, and lactone derivatives potentiated the electrical responses of GABA(A) receptors, especially ethyl phenylpropanoate (EPP), which strongly potentiated the response. When this compound was applied to mice through respiration, the convulsions induced by pentetrazole were delayed, suggesting that EPP was absorbed by the brain, where it could potentiate the GABA(A) receptor responses. The extract of other alcoholic drinks such as wine, sake, brandy, and shochu also potentiated the responses to varying degrees. Although these fragrant components are present in alcoholic drinks at low concentrations (extremely small quantities compared with ethanol), they may also modulate the mood or consciousness of the human through the potentiation of the GABA(A) receptor response after absorption into the brain, because these hydrophobic fragrant compounds are easily absorbed into the brain through the blood-brain barrier and are several thousands times as potent as ethanol in the potentiation of the GABA(A) receptor-mediated response.

  12. Potentiation of the ionotropic GABA receptor response by whiskey fragrance.

    PubMed

    Hossain, Sheikh Julfikar; Aoshima, Hitoshi; Koda, Hirofumi; Kiso, Yoshinobu

    2002-11-01

    It is well-known that the target of most mood-defining compounds is an ionotropic gamma-aminobutyric acid receptor (GABA(A) receptor). The potentiation of the response of these inhibitory neurotransmitter receptors induces anxiolytic, sedative, and anesthetic activity in the human brain. To study the effects of whiskey fragrance on the GABA(A) receptor-mediated response, GABA(A) receptors were expressed in Xenopus oocyte by injecting rat whole brain mRNA or cRNA prepared from the cloned cDNA for the alpha(1) and beta(1) subunits of the bovine receptors. Most whiskey components such as phenol, ethoxy, and lactone derivatives potentiated the electrical responses of GABA(A) receptors, especially ethyl phenylpropanoate (EPP), which strongly potentiated the response. When this compound was applied to mice through respiration, the convulsions induced by pentetrazole were delayed, suggesting that EPP was absorbed by the brain, where it could potentiate the GABA(A) receptor responses. The extract of other alcoholic drinks such as wine, sake, brandy, and shochu also potentiated the responses to varying degrees. Although these fragrant components are present in alcoholic drinks at low concentrations (extremely small quantities compared with ethanol), they may also modulate the mood or consciousness of the human through the potentiation of the GABA(A) receptor response after absorption into the brain, because these hydrophobic fragrant compounds are easily absorbed into the brain through the blood-brain barrier and are several thousands times as potent as ethanol in the potentiation of the GABA(A) receptor-mediated response. PMID:12405783

  13. CB2 Cannabinoid Receptor As Potential Target against Alzheimer's Disease

    PubMed Central

    Aso, Ester; Ferrer, Isidro

    2016-01-01

    The CB2 receptor is one of the components of the endogenous cannabinoid system, a complex network of signaling molecules and receptors involved in the homeostatic control of several physiological functions. Accumulated evidence suggests a role for CB2 receptors in Alzheimer's disease (AD) and indicates their potential as a therapeutic target against this neurodegenerative disease. Levels of CB2 receptors are significantly increased in post-mortem AD brains, mainly in microglia surrounding senile plaques, and their expression levels correlate with the amounts of Aβ42 and β-amyloid plaque deposition. Moreover, several studies on animal models of AD have demonstrated that specific CB2 receptor agonists, which are devoid of psychoactive effects, reduce AD-like pathology, resulting in attenuation of the inflammation associated with the disease but also modulating Aβ and tau aberrant processing, among other effects. CB2 receptor activation also improves cognitive impairment in animal models of AD. This review discusses available data regarding the role of CB2 receptors in AD and the potential usefulness of specific agonists of these receptors against AD. PMID:27303261

  14. Discoidin Domain Receptors: Potential Actors and Targets in Cancer

    PubMed Central

    Rammal, Hassan; Saby, Charles; Magnien, Kevin; Van-Gulick, Laurence; Garnotel, Roselyne; Buache, Emilie; El Btaouri, Hassan; Jeannesson, Pierre; Morjani, Hamid

    2016-01-01

    The extracellular matrix critically controls cancer cell behavior by inducing several signaling pathways through cell membrane receptors. Besides conferring structural properties to tissues around the tumor, the extracellular matrix is able to regulate cell proliferation, survival, migration, and invasion. Among these receptors, the integrins family constitutes a major class of receptors that mediate cell interactions with extracellular matrix components. Twenty years ago, a new class of extracellular matrix receptors has been discovered. These tyrosine kinase receptors are the two discoidin domain receptors DDR1 and DDR2. DDR1 was first identified in the Dictyostelium discoideum and was shown to mediate cell aggregation. DDR2 shares highly conserved sequences with DDR1. Both receptors are activated upon binding to collagen, one of the most abundant proteins in extracellular matrix. While DDR2 can only be activated by fibrillar collagen, particularly types I and III, DDR1 is mostly activated by type I and IV collagens. In contrast with classical growth factor tyrosine kinase receptors which display a rapid and transient activation, DDR1 and DDR2 are unique in that they exhibit delayed and sustained receptor phosphorylation upon binding to collagen. Recent studies have reported differential expression and mutations of DDR1 and DDR2 in several cancer types and indicate clearly that these receptors have to be taken into account as new players in the different aspects of tumor progression, from non-malignant to highly malignant and invasive stages. This review will discuss the current knowledge on the role of DDR1 and DDR2 in malignant transformation, cell proliferation, epithelial to mesenchymal transition, migratory, and invasive processes, and finally the modulation of the response to chemotherapy. These new insights suggest that DDR1 and DDR2 are new potential targets in cancer therapy. PMID:27014069

  15. Sphingosine-1-Phosphate Receptor-2 Antagonists: Therapeutic Potential and Potential Risks

    PubMed Central

    Blankenbach, Kira V.; Schwalm, Stephanie; Pfeilschifter, Josef; Meyer zu Heringdorf, Dagmar

    2016-01-01

    The sphingosine-1-phosphate (S1P) signaling system with its specific G-protein-coupled S1P receptors, the enzymes of S1P metabolism and the S1P transporters, offers a multitude of promising targets for drug development. Until today, drug development in this area has nearly exclusively focused on (functional) antagonists at the S1P1 receptor, which cause a unique phenotype of immunomodulation. Accordingly, the first-in class S1P1 receptor modulator, fingolimod, has been approved for the treatment of relapsing-remitting multiple sclerosis, and novel S1P1 receptor (functional) antagonists are being developed for autoimmune and inflammatory diseases such as psoriasis, inflammatory bowel disease, lupus erythematodes, or polymyositis. Besides the S1P1 receptor, also S1P2 and S1P3 are widely expressed and regulate many diverse functions throughout the body. The S1P2 receptor, in particular, often exerts cellular functions which are opposed to the functions of the S1P1 receptor. As a consequence, antagonists at the S1P2 receptor have the potential to be useful in a contrasting context and different areas of indication compared to S1P1 antagonists. The present review will focus on the therapeutic potential of S1P2 receptor antagonists and discuss their opportunities as well as their potential risks. Open questions and areas which require further investigations will be emphasized in particular. PMID:27445808

  16. Metabotropic glutamate receptors: their therapeutic potential in anxiety.

    PubMed

    Spooren, Will; Lesage, Anne; Lavreysen, Hilde; Gasparini, Fabrizio; Steckler, Thomas

    2010-01-01

    Psychiatric and neurological disorders are linked to changes in synaptic excitatory processes with a key role for glutamate, that is, the most abundant excitatory amino-acid. Molecular cloning of the metabotropic glutamate (mGlu) receptors has led to the identification of eight mGlu receptors, which, in contrast to ligand-gated ion channels (responsible for fast excitatory transmission), modulate and fine-tune the efficacy of synaptic transmission. mGlu receptors are G protein-coupled and constitute a new group of "drugable" targets for the treatment of various CNS disorders. The recent discovery of small molecules that selectively bind to receptors of Groups I (mGlu1 and mGlu5) and II (mGlu2 and mGlu3) allowed significant advances in our understanding of the roles of these receptors in brain function and dysfunction including anxiety. Although investigation of the role of the Group III (mGlu4, 6, 7, and 8) receptors is less advanced, the generation of genetically manipulated animals and recent advances in the identification of subtype-selective compounds have revealed some first insights into the therapeutic potential of this group of receptors. PMID:21309118

  17. Metabotropic glutamate receptors: their therapeutic potential in anxiety.

    PubMed

    Spooren, Will; Lesage, Anne; Lavreysen, Hilde; Gasparini, Fabrizio; Steckler, Thomas

    2010-01-01

    Psychiatric and neurological disorders are linked to changes in synaptic excitatory processes with a key role for glutamate, that is, the most abundant excitatory amino-acid. Molecular cloning of the metabotropic glutamate (mGlu) receptors has led to the identification of eight mGlu receptors, which, in contrast to ligand-gated ion channels (responsible for fast excitatory transmission), modulate and fine-tune the efficacy of synaptic transmission. mGlu receptors are G protein-coupled and constitute a new group of "drugable" targets for the treatment of various CNS disorders. The recent discovery of small molecules that selectively bind to receptors of Groups I (mGlu1 and mGlu5) and II (mGlu2 and mGlu3) allowed significant advances in our understanding of the roles of these receptors in brain function and dysfunction including anxiety. Although investigation of the role of the Group III (mGlu4, 6, 7, and 8) receptors is less advanced, the generation of genetically manipulated animals and recent advances in the identification of subtype-selective compounds have revealed some first insights into the therapeutic potential of this group of receptors.

  18. 5-Hydroxytryptamine Receptor Subtypes and their Modulators with Therapeutic Potentials

    PubMed Central

    Pithadia, Anand B.; Jain, Sunita M.

    2009-01-01

    5-hydroxytryptamine (5-HT) has become one of the most investigated and complex biogenic amines. The main receptors and their subtypes, e.g., 5-HTI (5-HT1A, 5-HT1B, 5-HTID, 5-HTIE and 5-HT1F), 5-HT2 (5-HT2A, 5-HT2B and 5-HT2C), 5-HT3, 5-HT4, 5-HT5 (5-HT5A, 5-HT5B), 5-HT6 and 5-HT7 have been identified. Specific drugs which are capable of either selectively stimulating or inhibiting these receptor subtypes are being designed. This has generated therapeutic potentials of 5-HT receptor modulators in a variety of disease conditions. Conditions where 5-HT receptor modulators have established their use with distinct efficacy and advantages include migraine, anxiety, psychosis, obesity and cancer therapy-induced vomiting by cytotoxic drugs and radiation. Discovery of 5-HT, its biosynthesis, metabolism, physiological role and the potential of 5-HT receptor modulators in various nervous, cardiovascular and gastrointestinal tract disorders, bone growth and micturition have been discussed in this article. Keywords 5-hydroxytryptamine (5-HT) receptors; Modulators; Biogenic amines PMID:22505971

  19. Propofol Restores Transient Receptor Potential Vanilloid Receptor Subtype-1 Sensitivity via Activation of Transient Receptor Potential Ankyrin Receptor Subtype-1 in Sensory Neurons

    PubMed Central

    Zhang, Hongyu; Wickley, Peter J.; Sinha, Sayantani; Bratz, Ian N.; Damron, Derek S.

    2011-01-01

    Background Crosstalk between peripheral nociceptors belonging to the transient receptor potential vanilloid receptor subtype-1 (TRPV1) and ankyrin subtype-1 (TRPA1) family has recently been demonstrated. Moreover, the intravenous anesthetic propofol has been shown to directly activate TRPA1 receptors, and indirectly restore sensitivity of TRPV1 receptors in dorsal root ganglion (DRG) sensory neurons. Our objective was to determine the extent to which TRPA1 activation is involved in mediating the propofol-induced restoration of TRPV1 sensitivity. Methods Mouse DRG neurons were isolated by enzymatic dissociation and grown for 24 h. F-11 cells were transfected with complementary DNA for both TRPV1 and TRPA1 or TRPV1 only. Intracellular Ca2+ concentration was measured in individual cells via fluorescence microscopy. Following TRPV1 de-sensitization with capsaicin (100 nM), cells were treated with propofol (1, 5 and 10 μM) alone, propofol in the presence of the TRPA1 antagonist, HC-030031 (0.5 μM) or the TRPA1 agonist, Allyl isothiocyanate (AITC, 100 μM) and capsaicin was then reapplied. Results In DRG neurons that contain both TRPV1 and TRPA1, propofol and AITC restored TRPV1 sensitivity. However, in DRG neurons containing only TRPV1 receptors, exposure to propofol or AITC following de-sensitization did not restore capsaicin-induced TRPV1 sensitivity. Similarly, in F-11 cells transfected with both TRPV1 and TRPA1, propofol and AITC restored TRPV1 sensitivity. However, in F-11 cells transfected with TRPV1 only, neither propofol nor AITC were capable of restoring TRPV1 sensitivity. Conclusions These data demonstrate that propofol restores TRPV1 sensitivity in primary DRG neurons and in cultured F-11 cells transfected with both the TRPV1 and TRPA1 receptors via a TRPA1-dependent process. Propofol’s effects on sensory neurons may be clinically important and contribute to peripheral sensitization to nociceptive stimuli in traumatized tissue. PMID:21364461

  20. International Union of Basic and Clinical Pharmacology. LXXIX. Cannabinoid Receptors and Their Ligands: Beyond CB1 and CB2

    PubMed Central

    Howlett, A. C.; Abood, M. E.; Alexander, S. P. H.; Di Marzo, V.; Elphick, M. R.; Greasley, P. J.; Hansen, H. S.; Kunos, G.; Mackie, K.; Mechoulam, R.; Ross, R. A.

    2010-01-01

    There are at least two types of cannabinoid receptors (CB1 and CB2). Ligands activating these G protein-coupled receptors (GPCRs) include the phytocannabinoid Δ9-tetrahydrocannabinol, numerous synthetic compounds, and endogenous compounds known as endocannabinoids. Cannabinoid receptor antagonists have also been developed. Some of these ligands activate or block one type of cannabinoid receptor more potently than the other type. This review summarizes current data indicating the extent to which cannabinoid receptor ligands undergo orthosteric or allosteric interactions with non-CB1, non-CB2 established GPCRs, deorphanized receptors such as GPR55, ligand-gated ion channels, transient receptor potential (TRP) channels, and other ion channels or peroxisome proliferator-activated nuclear receptors. From these data, it is clear that some ligands that interact similarly with CB1 and/or CB2 receptors are likely to display significantly different pharmacological profiles. The review also lists some criteria that any novel “CB3” cannabinoid receptor or channel should fulfil and concludes that these criteria are not currently met by any non-CB1, non-CB2 pharmacological receptor or channel. However, it does identify certain pharmacological targets that should be investigated further as potential CB3 receptors or channels. These include TRP vanilloid 1, which possibly functions as an ionotropic cannabinoid receptor under physiological and/or pathological conditions, and some deorphanized GPCRs. Also discussed are 1) the ability of CB1 receptors to form heteromeric complexes with certain other GPCRs, 2) phylogenetic relationships that exist between CB1/CB2 receptors and other GPCRs, 3) evidence for the existence of several as-yet-uncharacterized non-CB1, non-CB2 cannabinoid receptors; and 4) current cannabinoid receptor nomenclature. PMID:21079038

  1. Therapeutic potential of endothelin receptor antagonism in kidney disease.

    PubMed

    Czopek, Alicja; Moorhouse, Rebecca; Webb, David J; Dhaun, Neeraj

    2016-03-01

    Our growing understanding of the role of the endothelin (ET) system in renal physiology and pathophysiology is from emerging studies of renal disease in animal models and humans. ET receptor antagonists reduce blood pressure and proteinuria in chronic kidney disease and cause regression of renal injury in animals. However, the therapeutic potential of ET receptor antagonism has not been fully explored and clinical studies have been largely limited to patients with diabetic nephropathy. There remains a need for more work in nondiabetic chronic kidney disease, end-stage renal disease (patients requiring maintenance dialysis and those with a functioning kidney transplant), ischemia reperfusion injury, and sickle cell disease. The current review summarizes the most recent advances in both preclinical and clinical studies of ET receptor antagonists in the field of kidney disease.

  2. Involvement of central TRPV1 receptors in pentylenetetrazole and amygdala-induced kindling in male rats.

    PubMed

    Shirazi, Mohsen; Izadi, Mahin; Amin, Masoud; Rezvani, Mohammad Ebrahim; Roohbakhsh, Ali; Shamsizadeh, Ali

    2014-08-01

    Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel that is involved in modulation of diverse physiological processes. The role of this receptor in epilepsy has not been studied well. Therefore, we investigated the role of central TRPV1 receptors on the development of pentylenetetrazole (PTZ) and amygdala-induced kindling in rats. Male Wistar rats received subconvulsive dose of PTZ intraperitoneally, every other day. TRPV1 receptor agonist, OLDA and its antagonist, AMG-9810 were injected intracerebroventricularly 30 min prior to PTZ administration. In electrical kindling, stimulating and recording electrodes were implanted in the right amygdala of male rats. After kindling, the effect of TRPV1 receptor agonist or antagonist on afterdischarge duration (ADD), latency to the onset of bilateral forelimb clonuses (S4L) and duration of loss of equilibrium (stage 5 seizures, S5D) were measured. The results demonstrated that, OLDA at the doses of 0.01, 0.1 and 1 μg/rat, significantly accelerated the incidence of all seizure stages, increased S5D and decreased S4L in the PTZ model of kindling. Also, in amygdala kindling, S5D and ADD were significantly reduced following the administration of AMG-9810. In contrast, OLDA significantly aggravated the indices of seizure in both models of epileptic seizure. This study demonstrated that central TRPV1 receptors may be involved in the development of electrical and PTZ-induced kindling.

  3. Functional expression of purinergic P2 receptors and transient receptor potential channels by the human urothelium

    PubMed Central

    Shabir, Saqib; Cross, William; Kirkwood, Lisa A.; Pearson, Joanna F.; Appleby, Peter A.; Walker, Dawn; Eardley, Ian

    2013-01-01

    In addition to its role as a physical barrier, the urothelium is considered to play an active role in mechanosensation. A key mechanism is the release of transient mediators that activate purinergic P2 receptors and transient receptor potential (TRP) channels to effect changes in intracellular Ca2+. Despite the implied importance of these receptors and channels in urothelial tissue homeostasis and dysfunctional bladder disease, little is known about their functional expression by the human urothelium. To evaluate the expression and function of P2X and P2Y receptors and TRP channels, the human ureter and bladder were used to separate urothelial and stromal tissues for RNA isolation and cell culture. RT-PCR using stringently designed primer sets was used to establish which P2 and TRP species were expressed at the transcript level, and selective agonists/antagonists were used to confirm functional expression by monitoring changes in intracellular Ca2+ and in a scratch repair assay. The results confirmed the functional expression of P2Y4 receptors and excluded nonexpressed receptors/channels (P2X1, P2X3, P2X6, P2Y6, P2Y11, TRPV5, and TRPM8), while a dearth of specific agonists confounded the functional validation of expressed P2X2, P2X4, P2Y1, P2Y2, TRPV2, TRPV3, TRPV6 and TRPM7 receptors/channels. Although a conventional response was elicited in control stromal-derived cells, the urothelial cell response to well-characterized TRPV1 and TRPV4 agonists/antagonists revealed unexpected anomalies. In addition, agonists that invoked an increase in intracellular Ca2+ promoted urothelial scratch repair, presumably through the release of ATP. The study raises important questions about the ligand selectivity of receptor/channel targets expressed by the urothelium. These pathways are important in urothelial tissue homeostasis, and this opens the possibility of selective drug targeting. PMID:23720349

  4. Rapid Dark Recovery of the Invertebrate Early Receptor Potential

    PubMed Central

    Hillman, Peter; Dodge, F. A.; Hochstein, S.; Knight, B. W.; Minke, B.

    1973-01-01

    The recovery in the dark of the early receptor potential, as a direct manifestation of the state of the visual pigments, has been studied by intracellular recording in the ventral photoreceptors of Limulus and lateral photoreceptors of Balanus. The recovery is exponential with 1/e time constants of about 80 ms at 24°C for both preparations and 1800 ms at 4°C for Balanus. The 24°C rate extrapolates to total recovery of the pigment within 2 s. The later part of the dark adaptation of the late receptor potential, which may take from seconds to minutes in these preparations, appears thus to be unrelated to the state of the pigment. PMID:4713724

  5. Metabotropic glutamate receptor ligands as potential therapeutics for addiction

    PubMed Central

    Olive, M. F.

    2009-01-01

    There is now compelling evidence that the excitatory amino acid neurotransmitter glutamate plays a pivotal role in drug addiction and alcoholism. As a result, there has been increasing interest in developing glutamate-based therapies for the treatment of addictive disorders. Receptors for glutamate are primarily divided into two classes: ionotropic glutamate receptors (iGluRs) that mediate fast excitatory glutamate transmission, and metabotropic glutamate receptors (mGluRs), which are G-protein coupled receptors that mediate slower, modulatory glutamate transmission. Most iGluR antagonists, while showing some efficacy in animal models of addiction, exhibit serious side effects when tested in humans. mGluR ligands, on the other hand, which have been advanced to testing in clinical trials for various medical conditions, have demonstrated the ability to reduce drug reward, reinforcement, and relapse-like behaviors in animal studies. mGluR ligands that have been shown to be primarily effective are Group I (mGluR1 and mGluR5) negative allosteric modulators and Group II (mGluR2 and mGluR3) orthosteric presynaptic autoreceptor agonists. In this review, we will summarize findings from animal studies suggesting that these mGluR ligands may be of potential benefit in reducing on-going drug self-administration and may aid in the prevention of relapse. The neuroanatomical distribution of mGluR1, mGluR2/3, and mGluR5 receptors and the pharmacological properties of Group I negative allosteric modulators and Group II agonists will also be overviewed. Finally, we will discuss the current status of mGluR ligands in human clinical trials. PMID:19630739

  6. Allosterism and Structure in Thermally Activated Transient Receptor Potential Channels.

    PubMed

    Diaz-Franulic, Ignacio; Poblete, Horacio; Miño-Galaz, Germán; González, Carlos; Latorre, Ramón

    2016-07-01

    The molecular sensors that mediate temperature changes in living organisms are a large family of proteins known as thermosensitive transient receptor potential (TRP) ion channels. These membrane proteins are polymodal receptors that can be activated by cold or hot temperatures, depending on the channel subtype, voltage, and ligands. The stimuli sensors are allosterically coupled to a pore domain, increasing the probability of finding the channel in its ion conductive conformation. In this review we first discuss the allosteric coupling between the temperature and voltage sensor modules and the pore domain, and then discuss the thermodynamic foundations of thermo-TRP channel activation. We provide a structural overview of the molecular determinants of temperature sensing. We also posit an anisotropic thermal diffusion model that may explain the large temperature sensitivity of TRP channels. Additionally, we examine the effect of several ligands on TRP channel function and the evidence regarding their mechanisms of action. PMID:27297398

  7. Application potential of toll-like receptors in cancer immunotherapy

    PubMed Central

    Shi, Ming; Chen, Xi; Ye, Kangruo; Yao, Yuanfei; Li, Yu

    2016-01-01

    Abstract Toll-like receptors (TLRs), as the most important pattern recognition receptors in innate immunity, play a pivotal role in inducing immune response through recognition of microbial invaders or specific agonists. Recent studies have suggested that TLRs could serve as important regulators in the development of a variety of cancer. However, increasing evidences have shown that TLRs may display quite opposite outcomes in cancer development. Although several potential therapeutic Toll-like receptor ligands have been found, the mechanism and therapy prospect of TLRs in cancer development has to be further elucidated to accelerate the clinical application. By performing a systematic review of the present findings on TLRs in cancer immunology, we attempted to evaluate the therapeutic potential of TLRs in cancer therapy and elucidate the potential mechanism of cancer progress regulated by TLR signaling and the reported targets on TLRs for clinical application. An electronic databases search was conducted in PubMed, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database from their inception to February 1, 2016. The following keywords were used to search the databases: Toll-like receptors, cancer therapy, therapeutic target, innate immunity. Of 244 studies that were identified, 97 nonrelevant studies were excluded. In total, 147 full-text articles were assessed, and from these, 54 were excluded as they did not provide complete key information. Thus, 93 studies were considered eligible and included in the analysis. According to the data from the included trials, 14 TLR ligands (77.8%) from 82 studies have been demonstrated to display antitumor property in various cancers, whereas 4 ligands (22.2%) from 11 studies promote tumors. Among them, only 3 TLR ligands have been approved for cancer therapy, and 9 ligands were in clinical trials. In addition, the potential mechanism of recently reported targets on TLRs for clinical application was also

  8. AMPA receptor potentiation can prevent ethanol-induced intoxication.

    PubMed

    Jones, Nicholas; Messenger, Marcus J; O'Neill, Michael J; Oldershaw, Anna; Gilmour, Gary; Simmons, Rosa M A; Iyengar, Smriti; Libri, Vincenzo; Tricklebank, Mark; Williams, Steve C R

    2008-06-01

    We present a substantial series of behavioral and imaging experiments, which demonstrate, for the first time, that increasing AMPA receptor-mediated neurotransmission via administration of potent and selective biarylsulfonamide AMPA potentiators LY404187 and LY451395 reverses the central effects of an acutely intoxicating dose of ethanol in the rat. Using pharmacological magnetic resonance imaging (phMRI), we observed that LY404187 attenuated ethanol-induced reductions in blood oxygenation level dependent (BOLD) in the anesthetized rat brain. A similar attenuation was apparent when measuring local cerebral glucose utilization (LCGU) via C14-2-deoxyglucose autoradiography in freely moving conscious rats. Both LY404187 and LY451395 significantly and dose-dependently reversed ethanol-induced deficits in both motor coordination and disruptions in an operant task where animals were trained to press a lever for food reward. Both prophylactic and acute intervention treatment with LY404187 reversed ethanol-induced deficits in motor coordination. Given that LY451395 and related AMPA receptor potentiators/ampakines are tolerated in both healthy volunteers and elderly patients, these data suggest that such compounds may form a potential management strategy for acute alcohol intoxication.

  9. Binding Mode Prediction of Evodiamine within Vanilloid Receptor TRPV1

    PubMed Central

    Wang, Zhanli; Sun, Lidan; Yu, Hui; Zhang, Yanhui; Gong, Wuzhuang; Jin, Hongwei; Zhang, Liangren; Liang, Huaping

    2012-01-01

    Accurate assessment of the potential binding mode of drugs is crucial to computer-aided drug design paradigms. It has been reported that evodiamine acts as an agonist of the vanilloid receptor Transient receptor potential vanilloid-1 (TRPV1). However, the precise interaction between evodiamine and TRPV1 was still not fully understood. In this perspective, the homology models of TRPV1 were generated using the crystal structure of the voltage-dependent shaker family K+ channel as a template. We then performed docking and molecular dynamics simulation to gain a better understanding of the probable binding modes of evodiamine within the TRPV1 binding pocket. There are no significant interspecies differences in evodiamine binding in rat, human and rabbit TRPV1 models. Pharmacophore modeling further provided confidence for the validity of the docking studies. This study is the first to shed light on the structural determinants required for the interaction between TRPV1 and evodiamine, and gives new suggestions for the rational design of novel TRPV1 ligands. PMID:22942745

  10. Combined therapeutic potential of nuclear receptors with receptor tyrosine kinase inhibitors in lung cancer

    SciTech Connect

    Wairagu, Peninah M.; Park, Kwang Hwa; Kim, Jihye; Choi, Jong-Whan; Kim, Hyun-Won; Yeh, Byung-Il; Jung, Soon-Hee; Yong, Suk-Joong; Jeong, Yangsik

    2014-05-09

    Highlights: • The 48 NR genes and 48 biological anti-cancer targets are profiled in paired-cells. • Growth inhibition by NR ligands or TKIs is target receptor level-dependent. • T0901317 with gefitinib/PHA665752 shows additive growth inhibition in lung cells. - Abstract: Cancer heterogeneity is a big hurdle in achieving complete cancer treatment, which has led to the emergence of combinational therapy. In this study, we investigated the potential use of nuclear receptor (NR) ligands for combinational therapy with other anti-cancer drugs. We first profiled all 48 NRs and 48 biological anti-cancer targets in four pairs of lung cell lines, where each pair was obtained from the same patient. Two sets of cell lines were normal and the corresponding tumor cell lines while the other two sets consisted of primary versus metastatic tumor cell lines. Analysis of the expression profile revealed 11 NRs and 15 cancer targets from the two pairs of normal versus tumor cell lines, and 9 NRs and 9 cancer targets from the primary versus metastatic tumor cell lines had distinct expression patterns in each category. Finally, the evaluation of nuclear receptor ligand T0901317 for liver X receptor (LXR) demonstrated its combined therapeutic potential with tyrosine kinase inhibitors. The combined treatment of cMET inhibitor PHA665752 or EGFR inhibitor gefitinib with T0901317 showed additive growth inhibition in both H2073 and H1993 cells. Mechanistically, the combined treatment suppressed cell cycle progression by inhibiting cyclinD1 and cyclinB expression. Taken together, this study provides insight into the potential use of NR ligands in combined therapeutics with other biological anti-cancer drugs.

  11. Glycine Potentiates AMPA Receptor Function through Metabotropic Activation of GluN2A-Containing NMDA Receptors

    PubMed Central

    Li, Li-Jun; Hu, Rong; Lujan, Brendan; Chen, Juan; Zhang, Jian-Jian; Nakano, Yasuko; Cui, Tian-Yuan; Liao, Ming-Xia; Chen, Jin-Cao; Man, Heng-Ye; Feng, Hua; Wan, Qi

    2016-01-01

    NMDA receptors are Ca2+-permeable ion channels. The activation of NMDA receptors requires agonist glutamate and co-agonist glycine. Recent evidence indicates that NMDA receptor also has metabotropic function. Here we report that in cultured mouse hippocampal neurons, glycine increases AMPA receptor-mediated currents independent of the channel activity of NMDA receptors and the activation of glycine receptors. The potentiation of AMPA receptor function by glycine is antagonized by the inhibition of ERK1/2. In the hippocampal neurons and in the HEK293 cells transfected with different combinations of NMDA receptors, glycine preferentially acts on GluN2A-containing NMDA receptors (GluN2ARs), but not GluN2B-containing NMDA receptors (GluN2BRs), to enhance ERK1/2 phosphorylation independent of the channel activity of GluN2ARs. Without requiring the channel activity of GluN2ARs, glycine increases AMPA receptor-mediated currents through GluN2ARs. Thus, these results reveal a metabotropic function of GluN2ARs in mediating glycine-induced potentiation of AMPA receptor function via ERK1/2 activation. PMID:27807405

  12. Transient receptor potential channel C5 in cancer chemoresistance

    PubMed Central

    He, Dong-xu; Ma, Xin

    2016-01-01

    The transient receptor potential (TRP) superfamily contains at least 28 homologs in mammalian. These proteins form TRP channels are permeable to monovalent and divalent cations and participate in a variety of physiological functions. Dysregulation of TRP channels is responsible for numerous diseases. This review provides a brief short overview of mammalian TRP channels with a focus on TRPC5 and its role in cancers. Dysregulation of TRPC5 interrupts Ca2+ homeostasis in cancer cells, which activates signaling pathways that are highly associated with cancer progression, especially cancer chemoresistance. Based on the important role of TRPC5, we also discuss the potential of TRPC5 as a target for therapeutic intervention. Either direct targeting of TRPC5 or indirect interruption of TRPC5-related signaling pathways may effectively overcome cancer chemoresistance. PMID:26657058

  13. Transient Receptor Potential (TRP) channels in T cells.

    PubMed

    Bertin, Samuel; Raz, Eyal

    2016-05-01

    The transient receptor potential (TRP) family of ion channels is widely expressed in many cell types and plays various physiological roles. Growing evidence suggests that certain TRP channels are functionally expressed in the immune system. Indeed, an increasing number of reports have demonstrated the functional expression of several TRP channels in innate and adaptive immune cells and have highlighted their critical role in the activation and function of these cells. However, very few reviews have been entirely dedicated to this subject. Here, we will summarize the recent findings with regards to TRP channel expression in T cells and discuss their emerging role as regulators of T cell activation and functions. Moreover, these studies suggest that beyond their pharmaceutical interest in pain management, certain TRP channels may represent potential novel therapeutic targets for various immune-related diseases.

  14. Main ion channels and receptors associated with visceral hypersensitivity in irritable bowel syndrome

    PubMed Central

    de Carvalho Rocha, Heraldo Arcela; Dantas, Bruna Priscilla Vasconcelos; Rolim, Thaísa Leite; Costa, Bagnólia Araújo; de Medeiros, Arnaldo Correia

    2014-01-01

    Irritable bowel syndrome (IBS) is a very frequent functional gastrointestinal disorder characterized by recurrent abdominal pain or discomfort and alteration of bowel habits. The IBS physiopathology is extremely complex. Visceral hypersensitivity plays an important role in the pathogenesis of abdominal pain in both in vitro and in vivo models of this functional disorder. In order to obtain a general view of the participation of the main ion channels and receptors regarding the visceral hypersensitivity in the IBS and to describe their chemical structure, a literature review was carried out. A bibliographical research in the following electronic databases: Pubmed and Virtual Library in Health (BVS) was fulfilled by using the search terms “ion channels” “or” “receptors” “and” “visceral hypersensitivity” “or” “visceral nociception” “and” “irritable bowel syndrome”. Original and review articles were considered for data acquisition. The activation of the ATP ion-gated channels, voltage-gated sodium (Nav) and calcium (Cav) channels, as well as the activation of protease-activated receptors (PAR2), transient receptor potential vanilloide-1, serotonin, cannabinoids and cholecystokinin are involved in the genesis of visceral hypersensitivity in IBS. The involvement of ion channels and receptors concerning visceral hypersensitivity is noteworthy in IBS models. PMID:24976114

  15. Hypersensitivity Induced by Activation of Spinal Cord PAR2 Receptors Is Partially Mediated by TRPV1 Receptors

    PubMed Central

    Mrozkova, Petra; Spicarova, Diana; Palecek, Jiri

    2016-01-01

    Protease-activated receptors 2 (PAR2) and transient receptor potential vanilloid 1 (TRPV1) receptors in the peripheral nerve endings are implicated in the development of increased sensitivity to mechanical and thermal stimuli, especially during inflammatory states. Both PAR2 and TRPV1 receptors are co-expressed in nociceptive dorsal root ganglion (DRG) neurons on their peripheral endings and also on presynaptic endings in the spinal cord dorsal horn. However, the modulation of nociceptive synaptic transmission in the superficial dorsal horn after activation of PAR2 and their functional coupling with TRPV1 is not clear. To investigate the role of spinal PAR2 activation on nociceptive modulation, intrathecal drug application was used in behavioural experiments and patch-clamp recordings of spontaneous, miniature and dorsal root stimulation-evoked excitatory postsynaptic currents (sEPSCs, mEPSCs, eEPSCs) were performed on superficial dorsal horn neurons in acute rat spinal cord slices. Intrathecal application of PAR2 activating peptide SLIGKV-NH2 induced thermal hyperalgesia, which was prevented by pretreatment with TRPV1 antagonist SB 366791 and was reduced by protein kinases inhibitor staurosporine. Patch-clamp experiments revealed robust decrease of mEPSC frequency (62.8 ± 4.9%), increase of sEPSC frequency (127.0 ± 5.9%) and eEPSC amplitude (126.9 ± 12.0%) in dorsal horn neurons after acute SLIGKV-NH2 application. All these EPSC changes, induced by PAR2 activation, were prevented by SB 366791 and staurosporine pretreatment. Our results demonstrate an important role of spinal PAR2 receptors in modulation of nociceptive transmission in the spinal cord dorsal horn at least partially mediated by activation of presynaptic TRPV1 receptors. The functional coupling between the PAR2 and TRPV1 receptors on the central branches of DRG neurons may be important especially during different pathological states when it may enhance pain perception. PMID:27755539

  16. Transient Receptor Potential Channels as Targets for Phytochemicals

    PubMed Central

    2015-01-01

    To date, 28 mammalian transient receptor potential (TRP) channels have been cloned and characterized. They are grouped into six subfamilies on the basis of their amino acid sequence homology: TRP Ankyrin (TRPA), TRP Canonical (TRPC), TRP Melastatin (TRPM), TRP Mucolipin (TRPML), TRP Polycystin (TRPP), and TRP Vanilloid (TRPV). Most of the TRP channels are nonselective cation channels expressed on the cell membrane and exhibit variable permeability ratios for Ca2+ versus Na+. They mediate sensory functions (such as vision, nociception, taste transduction, temperature sensation, and pheromone signaling) and homeostatic functions (such as divalent cation flux, hormone release, and osmoregulation). Significant progress has been made in our understanding of the specific roles of these TRP channels and their activation mechanisms. In this Review, the emphasis will be on the activation of TRP channels by phytochemicals that are claimed to exert health benefits. Recent findings complement the anecdotal evidence that some of these phytochemicals have specific receptors and the activation of which is responsible for the physiological effects. Now, the targets for these phytochemicals are being unveiled; a specific hypothesis can be proposed and tested experimentally to infer a scientific validity of the claims of the health benefits. The broader and pressing issues that have to be addressed are related to the quantities of the active ingredients in a given preparation, their bioavailability, metabolism, adverse effects, excretion, and systemic versus local effects. PMID:24926802

  17. Physiology and pathophysiology of canonical transient receptor potential channels

    PubMed Central

    Abramowitz, Joel; Birnbaumer, Lutz

    2009-01-01

    The existence of a mammalian family of TRPC ion channels, direct homologues of TRP, the visual transduction channel of flies, was discovered during 1995–1996 as a consequence of research into the mechanism by which the stimulation of the receptor-Gq-phospholipase Cβ signaling pathway leads to sustained increases in intracellular calcium. Mammalian TRPs, TRPCs, turned out to be nonselective, calcium-permeable cation channels, which cause both a collapse of the cell’s membrane potential and entry of calcium. The family comprises 7 members and is widely expressed. Many cells and tissues express between 3 and 4 of the 7 TRPCs. Despite their recent discovery, a wealth of information has accumulated, showing that TRPCs have widespread roles in almost all cells studied, including cells from excitable and nonexcitable tissues, such as the nervous and cardiovascular systems, the kidney and the liver, and cells from endothelia, epithelia, and the bone marrow compartment. Disruption of TRPC function is at the root of some familial diseases. More often, TRPCs are contributing risk factors in complex diseases. The present article reviews what has been uncovered about physiological roles of mammalian TRPC channels since the time of their discovery. This analysis reveals TRPCs as major and unsuspected gates of Ca2+ entry that contribute, depending on context, to activation of transcription factors, apoptosis, vascular contractility, platelet activation, and cardiac hypertrophy, as well as to normal and abnormal cell proliferation. TRPCs emerge as targets for a thus far nonexistent field of pharmacological intervention that may ameliorate complex diseases.—Abramowitz, J., Birnbaumer, L. Physiology and pathophysiology of canonical transient receptor potential channels. PMID:18940894

  18. Short latency compound action potentials from mammalian gravity receptor organs

    NASA Technical Reports Server (NTRS)

    Jones, T. A.; Jones, S. M.

    1999-01-01

    Gravity receptor function was characterized in four mammalian species using far-field vestibular evoked potentials (VsEPs). VsEPs are compound action potentials of the vestibular nerve and central relays that are elicited by linear acceleration ramps applied to the cranium. Rats, mice, guinea pigs, and gerbils were studied. In all species, response onset occurred within 1.5 ms of the stimulus onset. Responses persisted during intense (116 dBSPL) wide-band (50 to 50 inverted question mark omitted inverted question mark000 Hz) forward masking, whereas auditory responses to intense clicks (112 dBpeSPL) were eliminated under the same conditions. VsEPs remained after cochlear extirpation but were eliminated following bilateral labyrinthectomy. Responses included a series of positive and negative peaks that occurred within 8 ms of stimulus onset (range of means at +6 dBre: 1.0 g/ms: P1=908 to 1062 micros, N1=1342 to 1475 micros, P2=1632 to 1952 micros, N2=2038 to 2387 micros). Mean response amplitudes at +6 dBre: 1.0 g/ms ranged from 0.14 to 0.99 microV. VsEP input/output functions revealed latency slopes that varied across peaks and species ranging from -19 to -51 micros/dB. Amplitude-intensity slopes also varied ranging from 0.04 to 0.08 microV/dB for rats and mice. Latency values were comparable to those of birds although amplitudes were substantially smaller in mammals. VsEP threshold values were considerably higher in mammals compared to birds and ranged from -8.1 to -10.5 dBre 1.0 g/ms across species. These results support the hypothesis that mammalian gravity receptors are less sensitive to dynamic stimuli than are those of birds.

  19. Oligopyrrole Macrocycles: Receptors and Chemosensors for Potentially Hazardous Materials

    PubMed Central

    2011-01-01

    Oligopyrroles represent a diverse class of molecular receptors that have been utilized in a growing number of applications. Recently, these systems have attracted interest as receptors and chemosensors for hazardous materials, including harmful anionic species, high-valent actinide cations, and nitroaromatic explosives. These versatile molecular receptors have been used to develop rudimentary colorimetric and fluorimetric assays for hazardous materials. PMID:21465591

  20. Artificial sweeteners and salts producing a metallic taste sensation activate TRPV1 receptors.

    PubMed

    Riera, Céline E; Vogel, Horst; Simon, Sidney A; le Coutre, Johannes

    2007-08-01

    Throughout the world many people use artificial sweeteners (AS) for the purpose of reducing caloric intake. The most prominently used of these molecules include saccharin, aspartame (Nutrasweet), acesulfame-K, and cyclamate. Despite the caloric advantage they provide, one key concern in their use is their aversive aftertaste that has been characterized on a sensory level as bitter and/or metallic. Recently, it has been shown that the activation of particular T2R bitter taste receptors is partially involved with the bitter aftertaste sensation of saccharin and acesulfame-K. To more fully understand the biology behind these phenomena we have addressed the question of whether AS could stimulate transient receptor potential vanilloid-1 (TRPV1) receptors, as these receptors are activated by a large range of structurally different chemicals. Moreover, TRPV1 receptors and/or their variants are found in taste receptor cells and in nerve terminals throughout the oral cavity. Hence, TRPV1 activation could be involved in the AS aftertaste or even contribute to the poorly understood metallic taste sensation. Using Ca(2+) imaging on TRPV1 receptors heterologously expressed in the human embryonic kidney (HEK) 293 cells and on dissociated primary sensory neurons, we find that in both systems, AS activate TRPV1 receptors, and, moreover, they sensitize these channels to acid and heat. We also found that TRPV1 receptors are activated by CuSO(4), ZnSO(4), and FeSO(4), three salts known to produce a metallic taste sensation. In summary, our results identify a novel group of compounds that activate TRPV1 and, consequently, provide a molecular mechanism that may account for off tastes of sweeteners and metallic tasting salts.

  1. Are AMPA receptor positive allosteric modulators potential pharmacotherapeutics for addiction?

    PubMed

    Watterson, Lucas R; Olive, M Foster

    2013-01-01

    Positive allosteric modulators (PAMs) of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are a diverse class of compounds that increase fast excitatory transmission in the brain. AMPA PAMs have been shown to facilitate long-term potentiation, strengthen communication between various cortical and subcortical regions, and some of these compounds increase the production and release of brain-derived neurotrophic factor (BDNF) in an activity-dependent manner. Through these mechanisms, AMPA PAMs have shown promise as broad spectrum pharmacotherapeutics in preclinical and clinical studies for various neurodegenerative and psychiatric disorders. In recent years, a small collection of preclinical animal studies has also shown that AMPA PAMs may have potential as pharmacotherapeutic adjuncts to extinction-based or cue-exposure therapies for the treatment of drug addiction. The present paper will review this preclinical literature, discuss novel data collected in our laboratory, and recommend future research directions for the possible development of AMPA PAMs as anti-addiction medications. PMID:24380895

  2. Are AMPA Receptor Positive Allosteric Modulators Potential Pharmacotherapeutics for Addiction?

    PubMed Central

    Watterson, Lucas R.; Olive, M. Foster

    2013-01-01

    Positive allosteric modulators (PAMs) of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are a diverse class of compounds that increase fast excitatory transmission in the brain. AMPA PAMs have been shown to facilitate long-term potentiation, strengthen communication between various cortical and subcortical regions, and some of these compounds increase the production and release of brain-derived neurotrophic factor (BDNF) in an activity-dependent manner. Through these mechanisms, AMPA PAMs have shown promise as broad spectrum pharmacotherapeutics in preclinical and clinical studies for various neurodegenerative and psychiatric disorders. In recent years, a small collection of preclinical animal studies has also shown that AMPA PAMs may have potential as pharmacotherapeutic adjuncts to extinction-based or cue-exposure therapies for the treatment of drug addiction. The present paper will review this preclinical literature, discuss novel data collected in our laboratory, and recommend future research directions for the possible development of AMPA PAMs as anti-addiction medications. PMID:24380895

  3. Identification of potential glucocorticoid receptor therapeutic targets in multiple myeloma

    PubMed Central

    Thomas, Alexandra L.; Coarfa, Cristian; Qian, Jun; Wilkerson, Joseph J.; Rajapakshe, Kimal; Krett, Nancy L.; Gunaratne, Preethi H.; Rosen, Steven T.

    2015-01-01

    Glucocorticoids (GC) are a cornerstone of combination therapies for multiple myeloma. However, patients ultimately develop resistance to GCs frequently based on decreased glucocorticoid receptor (GR) expression. An understanding of the direct targets of GC actions, which induce cell death, is expected to culminate in potential therapeutic strategies for inducing cell death by regulating downstream targets in the absence of a functional GR. The specific goal of our research is to identify primary GR targets that contribute to GC-induced cell death, with the ultimate goal of developing novel therapeutics around these targets that can be used to overcome resistance to GCs in the absence of GR. Using the MM.1S glucocorticoid-sensitive human myeloma cell line, we began with the broad platform of gene expression profiling to identify glucocorticoid-regulated genes further refined by combination treatment with phosphatidylinositol-3’-kinase inhibition (PI3Ki). To further refine the search to distinguish direct and indirect targets of GR that respond to the combination GC and PI3Ki treatment of MM.1S cells, we integrated 1) gene expression profiles of combination GC treatment with PI3Ki, which induces synergistic cell death; 2) negative correlation between genes inhibited by combination treatment in MM.1S cells and genes over-expressed in myeloma patients to establish clinical relevance and 3) GR chromatin immunoprecipitation with massively parallel sequencing (ChIP-Seq) in myeloma cells to identify global chromatin binding for the glucocorticoid receptor (GR). Using established bioinformatics platforms, we have integrated these data sets to identify a subset of candidate genes that may form the basis for a comprehensive picture of glucocorticoid actions in multiple myeloma. As a proof of principle, we have verified two targets, namely RRM2 and BCL2L1, as primary functional targets of GR involved in GC-induced cell death. PMID:26715915

  4. The prostaglandin EP1 receptor potentiates kainate receptor activation via a protein kinase C pathway and exacerbates status epilepticus

    PubMed Central

    Rojas, Asheebo; Gueorguieva, Paoula; Lelutiu, Nadia; Quan, Yi; Shaw, Renee; Dingledine, Raymond

    2014-01-01

    Prostaglandin E2 (PGE2) regulates membrane excitability, synaptic transmission, plasticity, and neuronal survival. The consequences of PGE2 release following seizures has been the subject of much study. Here we demonstrate that the prostaglandin E2 receptor 1 (EP1, or Ptger1) modulates native kainate receptors, a family of ionotropic glutamate receptors widely expressed throughout the central nervous system. Global ablation of the EP1 gene in mice (EP1-KO) had no effect on seizure threshold after kainate injection but reduced the likelihood to enter status epilepticus. EP1-KO mice that did experience typical status epilepticus had reduced hippocampal neurodegeneration and a blunted inflammatory response. Further studies with native prostanoid and kainate receptors in cultured cortical neurons, as well as with recombinant prostanoid and kainate receptors expressed in Xenopus oocytes, demonstrated that EP1 receptor activation potentiates heteromeric but not homomeric kainate receptors via a second messenger cascade involving phospholipase C, calcium and protein kinase C. Three critical GluK5 C-terminal serines underlie the potentiation of the GluK2/GluK5 receptor by EP1 activation. Taken together, these results indicate that EP1 receptor activation during seizures, through a protein kinase C pathway, increases the probability of kainic acid induced status epilepticus, and independently promotes hippocampal neurodegeneration and a broad inflammatory response. PMID:24952362

  5. The pain receptor TRPV1 displays agonist-dependent activation stoichiometry.

    PubMed

    Hazan, Adina; Kumar, Rakesh; Matzner, Henry; Priel, Avi

    2015-07-21

    The receptor channel TRPV1 (Transient Receptor Potential Vanilloid 1) is expressed by primary afferent sensory neurons of the pain pathway, where it functions as a sensor of noxious heat and various chemicals, including eicosanoids, capsaicin, protons and peptide toxins. Comprised of four identical subunits that organize into a non-selective cationic permeable channel, this receptor has a variety of binding sites responsible for detecting their respective agonists. Although its physiological role as a chemosensor has been described in detail, the stoichiometry of TRPV1 activation by its different ligands remains unknown. Here, we combined the use of concatemeric constructs harboring mutated binding sites with patch-clamp recordings in order to determine the stoichiometry for TRPV1 activation through the vanilloid binding site and the outer-pore domain by capsaicin and protons, respectively. We show that, while a single capsaicin-bound subunit was sufficient to achieve a maximal open-channel lifetime, all four proton-binding sites were required. Thus, our results demonstrate a distinct stoichiometry of TRPV1 activation through two of its different agonist-binding domains.

  6. A potential role of odorant receptor agonists and antagonists in the treatment of infertility and contraception.

    PubMed

    Spehr, Marc; Hatt, Hanns

    2005-04-01

    In 1992, the identification of odorant receptor expression in mammalian testicular tissue prepared the ground for an ongoing debate about a potential role for these chemoreceptors in significant sperm behaviors, in particular chemotaxis. The identification of hOR17-4, a human testicular odorant receptor that mediates sperm chemotaxis in various bioassays, revealed the first potential key player in this reproductively relevant scenario. Detailed knowledge of the receptor's molecular receptive field, the discovery of a potent receptor antagonist, as well as specific insight into the receptor-linked signaling cascade(s), could establish a basis for pioneering future applications in fertility treatment and/or contraception. PMID:15898342

  7. Activation of transient receptor potential ankyrin 1 by eugenol.

    PubMed

    Chung, G; Im, S T; Kim, Y H; Jung, S J; Rhyu, M-R; Oh, S B

    2014-03-01

    Eugenol is a bioactive plant extract used as an analgesic agent in dentistry. The structural similarity of eugenol to cinnamaldehyde, an active ligand for transient receptor potential ankyrin 1 (TRPA1), suggests that eugenol might produce its effect via TRPA1, in addition to TRPV1 as we reported previously. In this study, we investigated the effect of eugenol on TRPA1, by fura-2-based calcium imaging and patch clamp recording in trigeminal ganglion neurons and in a heterologous expression system. As the result, eugenol induced robust calcium responses in rat trigeminal ganglion neurons that responded to a specific TRPA1 agonist, allyl isothiocyanate (AITC), and not to capsaicin. Capsazepine, a TRPV1 antagonist failed to inhibit eugenol-induced calcium responses in AITC-responding neurons. In addition, eugenol response was observed in trigeminal ganglion neurons from TRPV1 knockout mice and human embryonic kidney 293 cell lines that express human TRPA1, which was inhibited by TRPA1-specific antagonist HC-030031. Eugenol-evoked TRPA1 single channel activity and eugenol-induced TRPA1 currents were dose-dependent with EC50 of 261.5μM. In summary, these results demonstrate that the activation of TRPA1 might account for another molecular mechanism underlying the pharmacological action of eugenol.

  8. Lipid modulation of thermal transient receptor potential channels.

    PubMed

    Hernández-García, Enrique; Rosenbaum, Tamara

    2014-01-01

    There is a subgroup of transient receptor potential (TRP) ion channels that are responsive to temperature (thermo-TRP channels). These are important to a variety of sensory and physiological phenomena such as pain and taste perception. All thermo-TRP channels known to date are subject to modulation by lipidic molecules of many kinds, from the ubiquitous cholesterol to more specialized molecules such as prostaglandins. Although the mechanisms and sites of binding of lipids on thermo-TRPs are largely unknown, the explosion on research of lipids and ion channels has revealed previously unsuspected roles for them. Diacyl glycerol is a lipid produced by phospholipase C (PLC) and it was discovered to modulate TRP channels in the eye of the fly, and many mammal TRP channels have been found to interact with lipids. While most of the lipids acting on thermo-TRP channels have been found to activate them, there are a few capable of inhibition. Phosphatidylinositol 4,5-bisphosphate is even capable of both inhibition and activation on a couple of thermo-TRPs, depending on the cellular context. More data is required to assess the mechanism through which lipids affect thermo-TRP channel activity and the physiological importance of this interaction.

  9. Toll-like receptors: potential targets for lupus treatment.

    PubMed

    Wu, Yan-wei; Tang, Wei; Zuo, Jian-ping

    2015-12-01

    Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE.

  10. Toll-like receptors: potential targets for lupus treatment

    PubMed Central

    Wu, Yan-wei; Tang, Wei; Zuo, Jian-ping

    2015-01-01

    Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE. PMID:26592511

  11. Lipid modulation of thermal transient receptor potential channels.

    PubMed

    Hernández-García, Enrique; Rosenbaum, Tamara

    2014-01-01

    There is a subgroup of transient receptor potential (TRP) ion channels that are responsive to temperature (thermo-TRP channels). These are important to a variety of sensory and physiological phenomena such as pain and taste perception. All thermo-TRP channels known to date are subject to modulation by lipidic molecules of many kinds, from the ubiquitous cholesterol to more specialized molecules such as prostaglandins. Although the mechanisms and sites of binding of lipids on thermo-TRPs are largely unknown, the explosion on research of lipids and ion channels has revealed previously unsuspected roles for them. Diacyl glycerol is a lipid produced by phospholipase C (PLC) and it was discovered to modulate TRP channels in the eye of the fly, and many mammal TRP channels have been found to interact with lipids. While most of the lipids acting on thermo-TRP channels have been found to activate them, there are a few capable of inhibition. Phosphatidylinositol 4,5-bisphosphate is even capable of both inhibition and activation on a couple of thermo-TRPs, depending on the cellular context. More data is required to assess the mechanism through which lipids affect thermo-TRP channel activity and the physiological importance of this interaction. PMID:25366236

  12. Transient receptor potential (TRP) channels: a clinical perspective

    PubMed Central

    Kaneko, Yosuke; Szallasi, Arpad

    2014-01-01

    Transient receptor potential (TRP) channels are important mediators of sensory signals with marked effects on cellular functions and signalling pathways. Indeed, mutations in genes encoding TRP channels are the cause of several inherited diseases in humans (the so-called ‘TRP channelopathies’) that affect the cardiovascular, renal, skeletal and nervous systems. TRP channels are also promising targets for drug discovery. The initial focus of research was on TRP channels that are expressed on nociceptive neurons. Indeed, a number of potent, small-molecule TRPV1, TRPV3 and TRPA1 antagonists have already entered clinical trials as novel analgesic agents. There has been a recent upsurge in the amount of work that expands TRP channel drug discovery efforts into new disease areas such as asthma, cancer, anxiety, cardiac hypertrophy, as well as obesity and metabolic disorders. A better understanding of TRP channel functions in health and disease should lead to the discovery of first-in-class drugs for these intractable diseases. With this review, we hope to capture the current state of this rapidly expanding and changing field. LINKED ARTICLES This article is part of a themed section on the pharmacology of TRP channels. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-10 PMID:24102319

  13. Transient receptor potential channels and regulation of lung endothelial permeability

    PubMed Central

    2013-01-01

    Abstract This review highlights our current knowledge regarding expression of transient receptor potential (TRP) cation channels in lung endothelium and evidence for their involvement in regulation of lung endothelial permeability. Six mammalian TRP families have been identified and organized on the basis of sequence homology: TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPML (mucolipin), TRPP (polycystin), and TRPA (ankyrin). To date, only TRPC1/4, TRPC6, TRPV4, and TRPM2 have been extensively studied in lung endothelium. Calcium influx through each of these channels has been documented to increase lung endothelial permeability, although their channel-gating mechanisms, downstream signaling mechanisms, and impact on endothelial structure and barrier integrity differ. While other members of the TRPC, TRPV, and TRPM families may be expressed in lung endothelium, we have little or no evidence linking these to regulation of lung endothelial permeability. Further, neither the expression nor functional role(s) of any TRPML, TRPP, and TRPA family members has been studied in lung endothelium. In addition to this assessment organized by TRP channel family, we also discuss TRP channels and lung endothelial permeability from the perspective of lung endothelial heterogeneity, using outcomes of studies focused on TRPC1/4 and TRPV4 channels. The diversity within the TRP channel family and the relative paucity of information regarding roles of a number of these channels in lung endothelium make this field ripe for continued investigation. PMID:25006396

  14. Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles

    PubMed Central

    Seebacher, Frank; Murray, Shauna A.

    2007-01-01

    Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response. PMID:17356692

  15. Selective oestrogen receptor modulators differentially potentiate brain mitochondrial function.

    PubMed

    Irwin, R W; Yao, J; To, J; Hamilton, R T; Cadenas, E; Brinton, R D

    2012-01-01

    The mitochondrial energy-transducing capacity of the brain is important for long-term neurological health and is influenced by endocrine hormone responsiveness. The present study aimed to determine the role of oestrogen receptor (ER) subtypes in regulating mitochondrial function using selective agonists for ERα (propylpyrazoletriol; PPT) and ERβ (diarylpropionitrile; DPN). Ovariectomised female rats were treated with 17β-oestradiol (E(2) ), PPT, DPN or vehicle control. Both ER selective agonists significantly increased the mitochondrial respiratory control ratio and cytochrome oxidase (COX) activity relative to vehicle. Western blots of purified whole brain mitochondria detected ERα and, to a greater extent, ERβ localisation. Pre-treatment with DPN, an ERβ agonist, significantly increased ERβ association with mitochondria. In the hippocampus, DPN activated mitochondrial DNA-encoded COX I expression, whereas PPT was ineffective, indicating that mechanistically ERβ, and not ERα, activated mitochondrial transcriptional machinery. Both selective ER agonists increased protein expression of nuclear DNA-encoded COX IV, suggesting that activation of ERβ or ERα is sufficient. Selective ER agonists up-regulated a panel of bioenergetic enzymes and antioxidant defence proteins. Up-regulated proteins included pyruvate dehydrogenase, ATP synthase, manganese superoxide dismutase and peroxiredoxin V. In vitro, whole cell metabolism was assessed in live primary cultured hippocampal neurones and mixed glia. The results of analyses conducted in vitro were consistent with data obtained in vivo. Furthermore, lipid peroxides, accumulated as a result of hormone deprivation, were significantly reduced by E(2) , PPT and DPN. These findings suggest that the activation of both ERα and ERβ is differentially required to potentiate mitochondrial function in brain. As active components in hormone therapy, synthetically designed oestrogens as well as natural phyto-oestrogen cocktails

  16. Aging of whiskey increases the potentiation of GABA(A) receptor response.

    PubMed

    Koda, Hirofumi; Hossain, Sheikh Julfikar; Kiso, Yoshinobu; Aoshima, Hitoshi

    2003-08-27

    It is known that the target of most mood-defining compounds such as ethanol is an ionotropic gamma-aminobutyric acid receptor (GABA(A) receptor). The potentiation of the response of these inhibitory neurotransmitter receptors induces anxiolytic, sedative, and anesthetic activities in the human brain. Because both extracts of whiskey by pentane and fragrant components in whiskey potentiate the GABA(A) receptor-mediated response, GABA(A) receptors were expressed in Xenopus oocyte by injecting cRNAs prepared from the cloned cDNA for the alpha(1) and beta(1) subunits of the bovine receptors in order to study the effects of whiskey itself on the GABA(A) receptor-mediated response. Whiskey itself also potentiated the electrical responses of GABA(A) receptors generally more than ethanol at the same concentration as that of the whiskey. The potentiation of the GABA(A) receptor-mediated response increased with the aging period of the whiskey. Inhalation of whiskey to mice increased the sleeping time induced by pentobarbital more than that of the same concentration of ethanol as the whiskey. These results suggest that not only ethanol but also minor components in whiskey play an important role in the potentiation of GABA(A) receptor-mediated response and possibly the sedative effect of whiskey. Although the minor components are present in extremely small quantities compared with ethanol in alcoholic beverages, they may modulate the mood or consciousness of humans through the potentiation of the GABA(A) receptor response after absorption into the brain, because these hydrophobic compounds are easily absorbed into the brain across the blood-brain barrier and are several thousands times as potent as ethanol in the potentiation of the GABA(A) receptor-mediated response.

  17. Aging of whiskey increases the potentiation of GABA(A) receptor response.

    PubMed

    Koda, Hirofumi; Hossain, Sheikh Julfikar; Kiso, Yoshinobu; Aoshima, Hitoshi

    2003-08-27

    It is known that the target of most mood-defining compounds such as ethanol is an ionotropic gamma-aminobutyric acid receptor (GABA(A) receptor). The potentiation of the response of these inhibitory neurotransmitter receptors induces anxiolytic, sedative, and anesthetic activities in the human brain. Because both extracts of whiskey by pentane and fragrant components in whiskey potentiate the GABA(A) receptor-mediated response, GABA(A) receptors were expressed in Xenopus oocyte by injecting cRNAs prepared from the cloned cDNA for the alpha(1) and beta(1) subunits of the bovine receptors in order to study the effects of whiskey itself on the GABA(A) receptor-mediated response. Whiskey itself also potentiated the electrical responses of GABA(A) receptors generally more than ethanol at the same concentration as that of the whiskey. The potentiation of the GABA(A) receptor-mediated response increased with the aging period of the whiskey. Inhalation of whiskey to mice increased the sleeping time induced by pentobarbital more than that of the same concentration of ethanol as the whiskey. These results suggest that not only ethanol but also minor components in whiskey play an important role in the potentiation of GABA(A) receptor-mediated response and possibly the sedative effect of whiskey. Although the minor components are present in extremely small quantities compared with ethanol in alcoholic beverages, they may modulate the mood or consciousness of humans through the potentiation of the GABA(A) receptor response after absorption into the brain, because these hydrophobic compounds are easily absorbed into the brain across the blood-brain barrier and are several thousands times as potent as ethanol in the potentiation of the GABA(A) receptor-mediated response. PMID:12926865

  18. Beyond classical benzodiazepines: Novel therapeutic potential of GABAA receptor subtypes

    PubMed Central

    Rudolph, Uwe; Knoflach, Frédéric

    2012-01-01

    GABAA receptors are a family of ligand-gated ion channels which are essential for the regulation of central nervous system function. Benzodiazepines – which target GABAA receptors containing the α1, α2, α3, or α5 subunits non-selectively – have been in clinical use for decades and are still among the most widely prescribed drugs for the treatment of insomnia and anxiety disorders. However, their use is limited by side effects and the risk of drug dependence. In the past decade, the identification of separable key functions of GABAA receptor subtypes suggests that receptor subtype-selective compounds could overcome the limitations of classical benzodiazepines and, furthermore, might be valuable for novel indications, such as analgesia, depression, schizophrenia, cognitive enhancement and stroke. PMID:21799515

  19. The promise and potential pitfalls of chimeric antigen receptors.

    PubMed

    Sadelain, Michel; Brentjens, Renier; Rivière, Isabelle

    2009-04-01

    One important purpose of T cell engineering is to generate tumor-targeted T cells through the genetic transfer of antigen-specific receptors, which consist of either physiological, MHC-restricted T cell receptors (TCRs) or non MHC-restricted chimeric antigen receptors (CARs). CARs combine antigen-specificity and T cell activating properties in a single fusion molecule. First generation CARs, which included as their signaling domain the cytoplasmic region of the CD3zeta or Fc receptor gamma chain, effectively redirected T cell cytotoxicity but failed to enable T cell proliferation and survival upon repeated antigen exposure. Receptors encompassing both CD28 and CD3zeta are the prototypes for second generation CARs, which are now rapidly expanding to a diverse array of receptors with different functional properties. First generation CARs have been tested in phase I clinical studies in patients with ovarian cancer, renal cancer, lymphoma, and neuroblastoma, where they have induced modest responses. Second generation CARs, which are just now entering the clinical arena in the B cell malignancies and other cancers, will provide a more significant test for this approach. If the immunogenicity of CARs can be averted, the versatility of their design and HLA-independent antigen recognition will make CARs tools of choice for T cell engineering for the development of targeted cancer immunotherapies.

  20. Potentiation of GABAA receptors expressed in Xenopus oocytes by perfume and phytoncid.

    PubMed

    Aoshima, H; Hamamoto, K

    1999-04-01

    To study the effects of perfume and phytoncid on GABAA receptors, ionotropic GABAA receptors were expressed in Xenopus oocytes by injecting mRNAs that had been prepared from rat whole brain. Essential oil, perfume and such phytoncid as leaf alcohol, hinokitiol, pinene, eugenol, citronellol and citronellal potentiated the response in the presence of GABA at low concentrations (10 and 30 microM), possibly because they bound to the potentiation-site in GABAA receptors and increased the affinity of GABA to the receptors. Since it is known that the potentiation of GABAA receptors by benzodiazepine, barbiturate, steroids and anesthetics induces the anxiolytic, anticonvulsant and sedative activity or anesthetic effect, these results suggest the possibility that the intake of perfume or phytoncid through the lungs, the skin or the intestines modulates the neural transmission in the brain through ionotropic GABAA receptors and changes the frame of the human mind, as alcohol or tobacco does.

  1. Potentiation of Gamma Aminobutyric Acid Receptors (GABAAR) by Ethanol: How Are Inhibitory Receptors Affected?

    PubMed Central

    Förstera, Benjamin; Castro, Patricio A.; Moraga-Cid, Gustavo; Aguayo, Luis G.

    2016-01-01

    In recent years there has been an increase in the understanding of ethanol actions on the type A γ-aminobutyric acid chloride channel (GABAAR), a member of the pentameric ligand gated ion channels (pLGICs). However, the mechanism by which ethanol potentiates the complex is still not fully understood and a number of publications have shown contradictory results. Thus many questions still remain unresolved requiring further studies for a better comprehension of this effect. The present review concentrates on the involvement of GABAAR in the acute actions of ethanol and specifically focuses on the immediate, direct or indirect, synaptic and extra-synaptic modulatory effects. To elaborate on the immediate, direct modulation of GABAAR by acute ethanol exposure, electrophysiological studies investigating the importance of different subunits, and data from receptor mutants will be examined. We will also discuss the nature of the putative binding sites for ethanol based on structural data obtained from other members of the pLGICs family. Finally, we will briefly highlight the glycine gated chloride channel (GlyR), another member of the pLGIC family, as a suitable target for the development of new pharmacological tools. PMID:27199667

  2. The heterodimeric sweet taste receptor has multiple potential ligand binding sites.

    PubMed

    Cui, Meng; Jiang, Peihua; Maillet, Emeline; Max, Marianna; Margolskee, Robert F; Osman, Roman

    2006-01-01

    The sweet taste receptor is a heterodimer of two G protein coupled receptors, T1R2 and T1R3. This discovery has increased our understanding at the molecular level of the mechanisms underlying sweet taste. Previous experimental studies using sweet receptor chimeras and mutants show that there are at least three potential binding sites in this heterodimeric receptor. Receptor activity toward the artificial sweeteners aspartame and neotame depends on residues in the amino terminal domain of human T1R2. In contrast, receptor activity toward the sweetener cyclamate and the sweet taste inhibitor lactisole depends on residues within the transmembrane domain of human T1R3. Furthermore, receptor activity toward the sweet protein brazzein depends on the cysteine rich domain of human T1R3. Although crystal structures are not available for the sweet taste receptor, useful homology models can be developed based on appropriate templates. The amino terminal domain, cysteine rich domain and transmembrane helix domain of T1R2 and T1R3 have been modeled based on the crystal structures of metabotropic glutamate receptor type 1, tumor necrosis factor receptor, and bovine rhodopsin, respectively. We have used homology models of the sweet taste receptors, molecular docking of sweet ligands to the receptors, and site-directed mutagenesis of the receptors to identify potential ligand binding sites of the sweet taste receptor. These studies have led to a better understanding of the structure and function of this heterodimeric receptor, and can act as a guide for rational structure-based design of novel non-caloric sweeteners, which can be used in the fighting against obesity and diabetes. PMID:17168764

  3. The heterodimeric sweet taste receptor has multiple potential ligand binding sites.

    PubMed

    Cui, Meng; Jiang, Peihua; Maillet, Emeline; Max, Marianna; Margolskee, Robert F; Osman, Roman

    2006-01-01

    The sweet taste receptor is a heterodimer of two G protein coupled receptors, T1R2 and T1R3. This discovery has increased our understanding at the molecular level of the mechanisms underlying sweet taste. Previous experimental studies using sweet receptor chimeras and mutants show that there are at least three potential binding sites in this heterodimeric receptor. Receptor activity toward the artificial sweeteners aspartame and neotame depends on residues in the amino terminal domain of human T1R2. In contrast, receptor activity toward the sweetener cyclamate and the sweet taste inhibitor lactisole depends on residues within the transmembrane domain of human T1R3. Furthermore, receptor activity toward the sweet protein brazzein depends on the cysteine rich domain of human T1R3. Although crystal structures are not available for the sweet taste receptor, useful homology models can be developed based on appropriate templates. The amino terminal domain, cysteine rich domain and transmembrane helix domain of T1R2 and T1R3 have been modeled based on the crystal structures of metabotropic glutamate receptor type 1, tumor necrosis factor receptor, and bovine rhodopsin, respectively. We have used homology models of the sweet taste receptors, molecular docking of sweet ligands to the receptors, and site-directed mutagenesis of the receptors to identify potential ligand binding sites of the sweet taste receptor. These studies have led to a better understanding of the structure and function of this heterodimeric receptor, and can act as a guide for rational structure-based design of novel non-caloric sweeteners, which can be used in the fighting against obesity and diabetes.

  4. Modulation of neurosteroid potentiation by protein kinases at synaptic- and extrasynaptic-type GABAA receptors.

    PubMed

    Adams, Joanna M; Thomas, Philip; Smart, Trevor G

    2015-01-01

    GABAA receptors are important for inhibition in the CNS where neurosteroids and protein kinases are potent endogenous modulators. Acting individually, these can either enhance or depress receptor function, dependent upon the type of neurosteroid or kinase and the receptor subunit combination. However, in vivo, these modulators probably act in concert to fine-tune GABAA receptor activity and thus inhibition, although how this is achieved remains unclear. Therefore, we investigated the relationship between these modulators at synaptic-type α1β3γ2L and extrasynaptic-type α4β3δ GABAA receptors using electrophysiology. For α1β3γ2L, potentiation of GABA responses by tetrahydro-deoxycorticosterone was reduced after inhibiting protein kinase C, and enhanced following its activation, suggesting this kinase regulates neurosteroid modulation. In comparison, neurosteroid potentiation was reduced at α1β3(S408A,S409A)γ2L receptors, and unaltered by PKC inhibitors or activators, indicating that phosphorylation of β3 subunits is important for regulating neurosteroid activity. To determine whether extrasynaptic-type GABAA receptors were similarly modulated, α4β3δ and α4β3(S408A,S409A)δ receptors were investigated. Neurosteroid potentiation was reduced at both receptors by the kinase inhibitor staurosporine. By contrast, neurosteroid-mediated potentiation at α4(S443A)β3(S408A,S409A)δ receptors was unaffected by protein kinase inhibition, strongly suggesting that phosphorylation of α4 and β3 subunits is required for regulating neurosteroid activity at extrasynaptic receptors. Western blot analyses revealed that neurosteroids increased phosphorylation of β3(S408,S409) implying that a reciprocal pathway exists for neurosteroids to modulate phosphorylation of GABAA receptors. Overall, these findings provide important insight into the regulation of GABAA receptors in vivo, and into the mechanisms by which GABAergic inhibitory transmission may be simultaneously

  5. Expression and functionality of TRPV1 receptor in human MCF-7 and canine CF.41 cells.

    PubMed

    Vercelli, C; Barbero, R; Cuniberti, B; Odore, R; Re, G

    2015-06-01

    As canine mammary tumours (CMT) and human breast cancer share clinical and prognostic features, the former have been proposed as a model to study carcinogenesis and improved therapeutic treatment in human breast cancer. In recent years, it has been shown that transient receptor potential vanilloid 1 (TRPV1) is expressed in different neoplastic tissues and its activation has been associated with regulation of cancer growth and progression. The aim of the present research was to demonstrate the presence of TRPV1 in human and canine mammary cancer cells, MCF-7 and CF.41, respectively, and to study the role of TRPV1 in regulating cell proliferation. The images obtained by Western blot showed a signal at 100 kDa corresponding to the molecular weight of TRPV1 receptor. All tested TRPV1 agonists and antagonists caused a significant decrease (P < 0.05) of cell growth rate in MCF-7 cells. By contrast, in CF.41 cells capsaicin and capsazepine induced a significant increase (P < 0.05) in cell proliferation, whereas resiniferatoxin (RTX) and 5-iodo-resiniferatoxin (5-I-RTX) had no influence on CF.41 cell proliferation. Further studies are needed to elucidate the underlying molecular mechanism responsible for the different effects evoked by TRPV1 activation in MCF-7 and CF.41 cells. PMID:23510405

  6. Biological roles and therapeutic potential of hydroxy-carboxylic Acid receptors.

    PubMed

    Ahmed, Kashan

    2011-01-01

    In the recent past, deorphanization studies have described intermediates of energy metabolism to activate G protein-coupled receptors and to thereby regulate metabolic functions. GPR81, GPR109A, and GPR109B, formerly known as the nicotinic acid receptor family, are encoded by clustered genes and share a high degree of sequence homology. Recently, hydroxy-carboxylic acids were identified as endogenous ligands of GPR81, GPR109A, and GPR109B, and therefore these receptors have been placed into a novel receptor family of hydroxy-carboxylic acid (HCA) receptors. The HCA(1) receptor (GPR81) is activated by the glycolytic metabolite 2-hydroxy-propionic acid (lactate), the HCA(2) receptor is activated by the ketone body 3-hydroxy-butyric acid, and the HCA(3) receptor (GPR109B) is a receptor for the β-oxidation intermediate 3-hydroxy-octanoic acid. While HCA(1) and HCA(2) receptors are present in most mammalian species, the HCA(3) receptor is exclusively found in humans and higher primates. HCA receptors are expressed in adipose tissue and mediate anti-lipolytic effects in adipocytes through G(i)-type G protein-dependent inhibition of adenylyl cyclase. HCA(2) and HCA(3) inhibit lipolysis during conditions of increased β-oxidation such as prolonged fasting, whereas HCA(1) mediates the anti-lipolytic effects of insulin in the fed state. As HCA(2) is a receptor for the established anti-dyslipidemic drug nicotinic acid, HCA(1) and HCA(3) also represent promising drug targets and several synthetic ligands for HCA receptors have been developed. In this article, we will summarize the deorphanization and pharmacological characterization of HCA receptors. Moreover, we will discuss recent progress in elucidating the physiological and pathophysiological role to further evaluate the therapeutic potential of the HCA receptor family for the treatment of metabolic disease.

  7. Therapeutic potential of Toll-like receptor 9 activation.

    PubMed

    Krieg, Arthur M

    2006-06-01

    In the decade since the discovery that mouse B cells respond to certain unmethylated CpG dinucleotides in bacterial DNA, a specific receptor for these 'CpG motifs' has been identified, Toll-like receptor 9 (TLR9), and a new approach to immunotherapy has moved into the clinic based on the use of synthetic oligodeoxynucleotides (ODN) as TLR9 agonists. This review highlights the current understanding of the mechanism of action of these CpG ODN, and provides an overview of the preclinical data and early human clinical trial results using these drugs to improve vaccines and treat cancer, infectious disease and allergy/asthma. PMID:16763660

  8. Receptor potentials of lizard hair cells with free-standing stereocilia: responses to acoustic clicks.

    PubMed Central

    Baden-Kristensen, K; Weiss, T F

    1983-01-01

    Receptor potentials of single hair cells in the free-standing region of the basilar papilla of the anaesthetized alligator lizard were measured intracellularly with micropipettes. Stimuli were primarily acoustic pulses (clicks) delivered to the tympanic membrane. The receptor potential was independent of click repetition rate for the range 10-150 clicks/s. This property is presumed to be the basis of the rate independence of the extracellular cochlear microphonic potential. The receptor potential wave-form consisted of a fast oscillatory component (or oscillation) superimposed on a usually positive (depolarizing) slow component. Reversal of the stimulus polarity resulted in a reversal of the polarity of the oscillations; the polarity of the slow component remained unchanged. The relative magnitudes of the two components depended on click level. At the higher click levels the magnitudes of the slow and oscillatory components were comparable. The relation of the receptor potential to the stimulus was non-linear; the peak-to-peak magnitude of the receptor potential increased less than proportionately with increasing sound-pressure level, and reversal of the stimulus polarity did not result in a reversal of the receptor potential. The receptor-potential magnitude for high-level clicks ranged from 1-13 mV peak-to-peak with an average value of 3.5 mV. At the lower click levels the magnitude of the slow component was much smaller than that of the oscillatory component. The relation of the receptor potential to the acoustic stimulus approached that of a linear system, the magnitude of the receptor potential became approximately proportional to the sound-pressure level, and reversal of the stimulus polarity resulted in approximate reversal of the receptor potential. For low-level stimuli the frequency of the oscillations of the receptor potential in response to clicks was approximately equal to the frequency of maximal a.c. response to tones. Apparently, both phenomena

  9. P2X7 receptor in epilepsy; role in pathophysiology and potential targeting for seizure control

    PubMed Central

    Engel, Tobias; Jimenez-Pacheco, Alba; Miras-Portugal, Maria Teresa; Diaz-Hernandez, Miguel; Henshall, David C

    2012-01-01

    The P2X7 receptor is an ATP-gated non-selective cation-permeable ionotropic receptor selectively expressed in neurons and glia in the brain. Activation of the P2X7 receptor has been found to modulate neuronal excitability in the hippocampus and it has also been linked to microglia activation and neuroinflammatory responses. Accordingly, interest developed on the P2X7 receptor in disorders of the nervous system, including epilepsy. Studies show that expression of the P2X7 receptor is elevated in damaged regions of the brain after prolonged seizures (status epilepticus) in both neurons and glia. P2X7 receptor expression is also increased in the hippocampus in experimental epilepsy. Recent data show that mice lacking the P2X7 receptor display altered susceptibility to status epilepticus and that drugs targeting the P2X7 receptor have potent anticonvulsant effects. Together, this suggests that P2X7 receptor ligands may be useful adjunctive treatments for refractory status epilepticus or perhaps pharmacoresistant epilepsy. This review summarizes the evidence of P2X7 receptor involvement in the pathophysiology of epilepsy and the potential of drugs targeting this receptor for seizure control. PMID:23320131

  10. The potential for Toll-like receptors to collaborate with other innate immune receptors

    PubMed Central

    Mukhopadhyay, Subhankar; Herre, Jurgen; Brown, Gordon D; Gordon, Siamon

    2004-01-01

    Cells of the innate immune system express a large repertoire of germ-line encoded cell-surface glycoprotein receptors including Toll-like receptors (TLRs). TLRs recognize conserved motifs on microbes and induce inflammatory signals. Evidence suggests that individual members of the TLR family or other non-TLR surface antigens either physically or functionally interact with each other and cumulative effects of these interactions instruct the nature and outcome of the immune response to a particular pathogen. PMID:15270722

  11. ROLE OF NMDA, NICOTINIC, AND GABA RECEPTORS IN THE STEADY STATE VISUAL EVOKED POTENTIAL IN RATS.

    EPA Science Inventory

    This manuscript characterizes the receptor pathways involved in pattern-evoked potential generation in rats

    " NMDA and nicotinic acetylcholine receptors appear to be involved in the generation of the steady-state pattern evoked response in vivo.

    " The pattern evok...

  12. Potential biological functions emerging from the different estrogen receptors.

    PubMed

    Carpenter, Karen D; Korach, Kenneth S

    2006-12-01

    Technological advances and new tools have brought about tremendous advances in elucidating the roles of estradiol and the estrogen receptors (ERs) in biological processes, especially within the female reproductive system. Development and analysis of multiple genetic models have provided insight into the particular functions of each of the ERs. This article reviews the insights into ER biology in female reproduction gained from the development and use of new types of experimental models.

  13. Pattern recognition receptors as potential therapeutic targets in inflammatory rheumatic disease.

    PubMed

    Mullen, Lisa M; Chamberlain, Giselle; Sacre, Sandra

    2015-05-15

    The pattern recognition receptors of the innate immune system are part of the first line of defence against pathogens. However, they also have the ability to respond to danger signals that are frequently elevated during tissue damage and at sites of inflammation. Inadvertent activation of pattern recognition receptors has been proposed to contribute to the pathogenesis of many conditions including inflammatory rheumatic diseases. Prolonged inflammation most often results in pain and damage to tissues. In particular, the Toll-like receptors and nucleotide-binding oligomerisation domain-like receptors that form inflammasomes have been postulated as key contributors to the inflammation observed in rheumatoid arthritis, osteoarthritis, gout and systemic lupus erythematosus. As such, there is increasing interest in targeting these receptors for therapeutic treatment in the clinic. Here the role of pattern recognition receptors in the pathogenesis of these diseases is discussed, with an update on the development of interventions to modulate the activity of these potential therapeutic targets.

  14. Endothelin receptor polymorphisms in the cardiovascular system: potential implications for therapy and screening.

    PubMed

    Holzhauser, Luise; Zolty, Ronald

    2014-11-01

    Since its discovery in 1988, the endothelin system has been employed in multiple physiological and pathological roles. Endothelin-1 (ET-1) is not only a major regulator of vascular tone and cardiac contractility but also exerts mitogenic effects and is involved in inflammatory responses. ET-1 acts via two endothelin receptors located mainly on smooth muscle and endothelial cells through complex intracellular pathways differing between receptors and cell types. Polymorphisms of the endothelin receptor A have been associated not only with the risk in pulmonary arterial hypertension (PAH), systolic heart failure and systemic hypertension but are also of prognostic significance in dilated cardiomyopathy. Polymorphisms of endothelin receptors might lead to altered endothelin signaling and influence the response to endothelin receptor antagonist therapy in PAH in light of pharmacogenetics. This review will summarize the role of ET-1 within major cardiovascular pathologies and discuss endothelin receptor polymorphisms with special emphasis on potential therapeutic and screening implications.

  15. Moderate AMPA receptor clustering on the nanoscale can efficiently potentiate synaptic current

    PubMed Central

    Savtchenko, Leonid P.; Rusakov, Dmitri A.

    2014-01-01

    The prevailing view at present is that postsynaptic expression of the classical NMDA receptor-dependent long-term potentiation relies on an increase in the numbers of local AMPA receptors (AMPARs). This is thought to parallel an expansion of postsynaptic cell specializations, for instance dendritic spine heads, which accommodate synaptic receptor proteins. However, glutamate released into the synaptic cleft can normally activate only a hotspot of low-affinity AMPARs that occur in the vicinity of the release site. How the enlargement of the AMPAR pool is causally related to the potentiated AMPAR current remains therefore poorly understood. To understand possible scenarios of postsynaptic potentiation, here we explore a detailed Monte Carlo model of the typical small excitatory synapse. Simulations suggest that approximately 50% increase in the synaptic AMPAR current could be provided by expanding the existing AMPAR pool at the expense of 100–200% new AMPARs added at the same packing density. Alternatively, reducing the inter-receptor distances by only 30–35% could achieve a similar level of current potentiation without any changes in the receptor numbers. The NMDA receptor current also appears sensitive to the NMDA receptor crowding. Our observations provide a quantitative framework for understanding the ‘resource-efficient’ ways to enact use-dependent changes in the architecture of central synapses. PMID:24298165

  16. TRPV1: A Potential Drug Target for Treating Various Diseases

    PubMed Central

    Brito, Rafael; Sheth, Sandeep; Mukherjea, Debashree; Rybak, Leonard P.; Ramkumar, Vickram

    2014-01-01

    Transient receptor potential vanilloid 1 (TRPV1) is an ion channel present on sensory neurons which is activated by heat, protons, capsaicin and a variety of endogenous lipids termed endovanilloids. As such, TRPV1 serves as a multimodal sensor of noxious stimuli which could trigger counteractive measures to avoid pain and injury. Activation of TRPV1 has been linked to chronic inflammatory pain conditions and peripheral neuropathy, as observed in diabetes. Expression of TRPV1 is also observed in non-neuronal sites such as the epithelium of bladder and lungs and in hair cells of the cochlea. At these sites, activation of TRPV1 has been implicated in the pathophysiology of diseases such as cystitis, asthma and hearing loss. Therefore, drugs which could modulate TRPV1 channel activity could be useful for the treatment of conditions ranging from chronic pain to hearing loss. This review describes the roles of TRPV1 in the normal physiology and pathophysiology of selected organs of the body and highlights how drugs targeting this channel could be important clinically. PMID:24861977

  17. P2X receptors in the cardiovascular system and their potential as therapeutic targets in disease.

    PubMed

    Ralevic, Vera

    2015-01-01

    This review considers the expression and roles of P2X receptors in the cardiovascular system in health and disease and their potential as therapeutic targets. P2X receptors are ligand gated ion channels which are activated by the endogenous ligand ATP. They are formed from the assembly of three P2X subunit proteins from the complement of seven (P2X1-7), which can associate to form homomeric or heteromeric P2X receptors. The P2X1 receptor is widely expressed in the cardiovascular system, being located in the heart, in the smooth muscle of the majority of blood vessels and in platelets. P2X1 receptors expressed in blood vessels can be activated by ATP coreleased with noradrenaline as a sympathetic neurotransmitter, leading to smooth muscle depolarisation and contraction. There is evidence that the purinergic component of sympathetic neurotransmission is increased in hypertension, identifying P2X1 receptors as a possible therapeutic target in this disorder. P2X3 and P2X2/3 receptors are expressed on cardiac sympathetic neurones and may, through positive feedback of neuronal ATP at this prejunctional site, amplify sympathetic neurotransmission. Activation of P2X receptors expressed in the heart increases cardiac myocyte contractility, and an important role of the P2X4 receptor in this has been identified. Deletion of P2X4 receptors in the heart depresses contractile performance in models of heart failure, while overexpression of P2X4 receptors has been shown to be cardioprotective, thus P2X4 receptors may be therapeutic targets in the treatment of heart disease. P2X receptors have been identified on endothelial cells. Although immunoreactivity for all P2X1-7 receptor proteins has been shown on the endothelium, relatively little is known about their function, with the exception of the endothelial P2X4 receptor, which has been shown to mediate endothelium-dependent vasodilatation to ATP released during shear stress. The potential of P2X receptors as therapeutic targets

  18. Endocytic Trafficking and Recycling Maintain a Pool of Mobile Surface AMPA Receptors Required for Synaptic Potentiation

    PubMed Central

    Petrini, Enrica Maria; Lu, Jiuyi; Cognet, Laurent; Lounis, Brahim; Ehlers, Michael D.; Choquet, Daniel

    2010-01-01

    SUMMARY At excitatory glutamatergic synapses, postsynaptic endocytic zones (EZs), which are adjacent to the postsynaptic density (PSD), mediate clathrin-dependent endocytosis of surface AMPA Receptors (AMPAR) as a first step to receptor recycling or degradation. However, it remains unknown if receptor recycling influences AMPARs lateral diffusion, and if EZs are important for the expression of synaptic potentiation. Here we demonstrate that the presence of both EZs and AMPAR recycling maintain a large pool of mobile AMPARs at synapses. In addition, we find that synaptic potentiation is accompanied by an accumulation and immobilization of AMPARs at synapses resulting from both their exocytosis and stabilization at the PSD. Displacement of EZs from the postsynaptic region impairs the expression of synaptic potentiation by blocking AMPAR recycling. Thus receptor recycling is crucial for maintaining a mobile population of surface AMPARs which can be delivered to synapses for increases in synaptic strength. PMID:19607795

  19. Enhanced neurosteroid potentiation of ternary GABA(A) receptors containing the delta subunit.

    PubMed

    Wohlfarth, Kai M; Bianchi, Matt T; Macdonald, Robert L

    2002-03-01

    Attenuated behavioral sensitivity to neurosteroids has been reported for mice deficient in the GABA(A) receptor delta subunit. We therefore investigated potential subunit-specific neurosteroid pharmacology of the following GABA(A) receptor isoforms in a transient expression system: alpha1beta3gamma2L, alpha1beta3delta, alpha6beta3gamma2L, and alpha6beta3delta. Potentiation of submaximal GABA(A) receptor currents by the neurosteroid tetrahydrodeoxycorticosterone (THDOC) was greatest for the alpha1beta3delta isoform. Whole-cell GABA concentration--response curves performed with and without low concentrations (30 nm) of THDOC revealed enhanced peak GABA(A) receptor currents for isoforms tested without affecting the GABA EC50. Alpha1beta3delta currents were enhanced the most (>150%), whereas the other isoform currents were enhanced 15-50%. At a higher concentration (1 microm), THDOC decreased peak alpha1beta3gamma2L receptor current amplitude evoked by GABA (1 mm) concentration jumps and prolonged deactivation but had little effect on the rate or extent of apparent desensitization. Thus the polarity of THDOC modulation depended on GABA concentration for alpha1beta3gamma2L GABA(A) receptors. However, the same protocol applied to alpha1beta3delta receptors resulted in peak current enhancement by THDOC of >800% and prolonged deactivation. Interestingly, THDOC induced pronounced desensitization in the minimally desensitizing alpha1beta3delta receptors. Single channel recordings obtained from alpha1beta3delta receptors indicated that THDOC increased the channel opening duration, including the introduction of an additional longer duration open state. Our results suggest that the GABA(A) receptor delta subunit confers increased sensitivity to neurosteroid modulation and that the intrinsic gating and desensitization kinetics of alpha1beta3delta GABA(A) receptors are altered by THDOC.

  20. Antibodies and Their Receptors: Different Potential Roles in Mucosal Defense

    PubMed Central

    Horton, Rachel E.; Vidarsson, Gestur

    2013-01-01

    Over recent years it has become increasingly apparent that mucosal antibodies are not only restricted to the IgM and IgA isotypes, but that also other isotypes and particularly IgG can be found in significant quantities at some mucosal surfaces, such as in the genital tract. Their role is more complex than traditionally believed with, among other things, the discovery of novel function of mucosal immunoglobulin receptors. A thorough knowledge in the source and function and mucosal immunoglobulins is particularly important in development of vaccines providing mucosal immunity, and also in the current climate of microbicide development, to combat major world health issues such as HIV. We present here a comprehensive review of human antibody mediated mucosal immunity. PMID:23882268

  1. The Elastin Receptor Complex: A Unique Matricellular Receptor with High Anti-tumoral Potential

    PubMed Central

    Scandolera, Amandine; Odoul, Ludivine; Salesse, Stéphanie; Guillot, Alexandre; Blaise, Sébastien; Kawecki, Charlotte; Maurice, Pascal; El Btaouri, Hassan; Romier-Crouzet, Béatrice; Martiny, Laurent; Debelle, Laurent; Duca, Laurent

    2016-01-01

    Elastin, one of the longest-lived proteins, confers elasticity to tissues with high mechanical constraints. During aging or pathophysiological conditions such as cancer progression, this insoluble polymer of tropoelastin undergoes an important degradation leading to the release of bioactive elastin-derived peptides (EDPs), named elastokines. EDP exhibit several biological functions able to drive tumor development by regulating cell proliferation, invasion, survival, angiogenesis, and matrix metalloproteinase expression in various tumor and stromal cells. Although, several receptors have been suggested to bind elastokines (αvβ3 and αvβ5 integrins, galectin-3), their main receptor remains the elastin receptor complex (ERC). This heterotrimer comprises a peripheral subunit, named elastin binding protein (EBP), associated to the protective protein/cathepsin A (PPCA). The latter is bound to a membrane-associated protein called Neuraminidase-1 (Neu-1). The pro-tumoral effects of elastokines have been linked to their binding onto EBP. Additionally, Neu-1 sialidase activity is essential for their signal transduction. Consistently, EDP-EBP interaction and Neu-1 activity emerge as original anti-tumoral targets. Interestingly, besides its direct involvement in cancer progression, the ERC also regulates diabetes outcome and thrombosis, an important risk factor for cancer development and a vascular process highly increased in patients suffering from cancer. In this review, we will describe ERC and elastokines involvement in cancer development suggesting that this unique receptor would be a promising therapeutic target. We will also discuss the pharmacological concepts aiming at blocking its pro-tumoral activities. Finally, its emerging role in cancer-associated complications and pathologies such as diabetes and thrombotic events will be also considered. PMID:26973522

  2. The Elastin Receptor Complex: A Unique Matricellular Receptor with High Anti-tumoral Potential.

    PubMed

    Scandolera, Amandine; Odoul, Ludivine; Salesse, Stéphanie; Guillot, Alexandre; Blaise, Sébastien; Kawecki, Charlotte; Maurice, Pascal; El Btaouri, Hassan; Romier-Crouzet, Béatrice; Martiny, Laurent; Debelle, Laurent; Duca, Laurent

    2016-01-01

    Elastin, one of the longest-lived proteins, confers elasticity to tissues with high mechanical constraints. During aging or pathophysiological conditions such as cancer progression, this insoluble polymer of tropoelastin undergoes an important degradation leading to the release of bioactive elastin-derived peptides (EDPs), named elastokines. EDP exhibit several biological functions able to drive tumor development by regulating cell proliferation, invasion, survival, angiogenesis, and matrix metalloproteinase expression in various tumor and stromal cells. Although, several receptors have been suggested to bind elastokines (αvβ3 and αvβ5 integrins, galectin-3), their main receptor remains the elastin receptor complex (ERC). This heterotrimer comprises a peripheral subunit, named elastin binding protein (EBP), associated to the protective protein/cathepsin A (PPCA). The latter is bound to a membrane-associated protein called Neuraminidase-1 (Neu-1). The pro-tumoral effects of elastokines have been linked to their binding onto EBP. Additionally, Neu-1 sialidase activity is essential for their signal transduction. Consistently, EDP-EBP interaction and Neu-1 activity emerge as original anti-tumoral targets. Interestingly, besides its direct involvement in cancer progression, the ERC also regulates diabetes outcome and thrombosis, an important risk factor for cancer development and a vascular process highly increased in patients suffering from cancer. In this review, we will describe ERC and elastokines involvement in cancer development suggesting that this unique receptor would be a promising therapeutic target. We will also discuss the pharmacological concepts aiming at blocking its pro-tumoral activities. Finally, its emerging role in cancer-associated complications and pathologies such as diabetes and thrombotic events will be also considered.

  3. Modulation of neurosteroid potentiation by protein kinases at synaptic- and extrasynaptic-type GABAA receptors

    PubMed Central

    Adams, Joanna M.; Thomas, Philip; Smart, Trevor G.

    2015-01-01

    GABAA receptors are important for inhibition in the CNS where neurosteroids and protein kinases are potent endogenous modulators. Acting individually, these can either enhance or depress receptor function, dependent upon the type of neurosteroid or kinase and the receptor subunit combination. However, in vivo, these modulators probably act in concert to fine-tune GABAA receptor activity and thus inhibition, although how this is achieved remains unclear. Therefore, we investigated the relationship between these modulators at synaptic-type α1β3γ2L and extrasynaptic-type α4β3δ GABAA receptors using electrophysiology. For α1β3γ2L, potentiation of GABA responses by tetrahydro-deoxycorticosterone was reduced after inhibiting protein kinase C, and enhanced following its activation, suggesting this kinase regulates neurosteroid modulation. In comparison, neurosteroid potentiation was reduced at α1β3S408A,S409Aγ2L receptors, and unaltered by PKC inhibitors or activators, indicating that phosphorylation of β3 subunits is important for regulating neurosteroid activity. To determine whether extrasynaptic-type GABAA receptors were similarly modulated, α4β3δ and α4β3S408A,S409Aδ receptors were investigated. Neurosteroid potentiation was reduced at both receptors by the kinase inhibitor staurosporine. By contrast, neurosteroid-mediated potentiation at α4S443Aβ3S408A,S409Aδ receptors was unaffected by protein kinase inhibition, strongly suggesting that phosphorylation of α4 and β3 subunits is required for regulating neurosteroid activity at extrasynaptic receptors. Western blot analyses revealed that neurosteroids increased phosphorylation of β3S408,S409 implying that a reciprocal pathway exists for neurosteroids to modulate phosphorylation of GABAA receptors. Overall, these findings provide important insight into the regulation of GABAA receptors in vivo, and into the mechanisms by which GABAergic inhibitory transmission may be simultaneously tuned by

  4. Lysophospholipid Receptors, as Novel Conditional Danger Receptors and Homeostatic Receptors Modulate Inflammation-Novel Paradigm and Therapeutic Potential.

    PubMed

    Wang, Xin; Li, Ya-Feng; Nanayakkara, Gayani; Shao, Ying; Liang, Bin; Cole, Lauren; Yang, William Y; Li, Xinyuan; Cueto, Ramon; Yu, Jun; Wang, Hong; Yang, Xiao-Feng

    2016-08-01

    There are limitations in the current classification of danger-associated molecular patterns (DAMP) receptors. To overcome these limitations, we propose a new paradigm by using endogenous metabolites lysophospholipids (LPLs) as a prototype. By utilizing a data mining method we pioneered, we made the following findings: (1) endogenous metabolites such as LPLs at basal level have physiological functions; (2) under sterile inflammation, expression of some LPLs is elevated. These LPLs act as conditional DAMPs or anti-inflammatory homeostasis-associated molecular pattern molecules (HAMPs) for regulating the progression of inflammation or inhibition of inflammation, respectively; (3) receptors for conditional DAMPs and HAMPs are differentially expressed in human and mouse tissues; and (4) complex signaling mechanism exists between pro-inflammatory mediators and classical DAMPs that regulate the expression of conditional DAMPs and HAMPs. This novel insight will facilitate identification of novel conditional DAMPs and HAMPs, thus promote development of new therapeutic targets to treat inflammatory disorders.

  5. The GABAA receptor is an FMRP target with therapeutic potential in fragile X syndrome

    PubMed Central

    Braat, Sien; D'Hulst, Charlotte; Heulens, Inge; De Rubeis, Silvia; Mientjes, Edwin; Nelson, David L; Willemsen, Rob; Bagni, Claudia; Van Dam, Debby; De Deyn, Peter P; Kooy, R Frank

    2015-01-01

    Previous research indicates that the GABAAergic system is involved in the pathophysiology of the fragile X syndrome, a frequent form of inherited intellectual disability and associated with autism spectrum disorder. However, the molecular mechanism underlying GABAAergic deficits has remained largely unknown. Here, we demonstrate reduced mRNA expression of GABAA receptor subunits in the cortex and cerebellum of young Fmr1 knockout mice. In addition, we show that the previously reported underexpression of specific subunits of the GABAA receptor can be corrected in YAC transgenic rescue mice, containing the full-length human FMR1 gene in an Fmr1 knockout background. Moreover, we demonstrate that FMRP directly binds several GABAA receptor mRNAs. Finally, positive allosteric modulation of GABAA receptors with the neurosteroid ganaxolone can modulate specific behaviors in Fmr1 knockout mice, emphasizing the therapeutic potential of the receptor. PMID:25790165

  6. P2Y Receptors in Synaptic Transmission and Plasticity: Therapeutic Potential in Cognitive Dysfunction

    PubMed Central

    Guzman, Segundo J.; Gerevich, Zoltan

    2016-01-01

    ATP released from neurons and astrocytes during neuronal activity or under pathophysiological circumstances is able to influence information flow in neuronal circuits by activation of ionotropic P2X and metabotropic P2Y receptors and subsequent modulation of cellular excitability, synaptic strength, and plasticity. In the present paper we review cellular and network effects of P2Y receptors in the brain. We show that P2Y receptors inhibit the release of neurotransmitters, modulate voltage- and ligand-gated ion channels, and differentially influence the induction of synaptic plasticity in the prefrontal cortex, hippocampus, and cerebellum. The findings discussed here may explain how P2Y1 receptor activation during brain injury, hypoxia, inflammation, schizophrenia, or Alzheimer's disease leads to an impairment of cognitive processes. Hence, it is suggested that the blockade of P2Y1 receptors may have therapeutic potential against cognitive disturbances in these states. PMID:27069691

  7. A novel putative tyrosine kinase receptor with oncogenic potential.

    PubMed

    Janssen, J W; Schulz, A S; Steenvoorden, A C; Schmidberger, M; Strehl, S; Ambros, P F; Bartram, C R

    1991-11-01

    We have detected transforming activity by a tumorigenicity assay using NIH3T3 cells transfected with DNA from a chronic myeloproliferative disorder patient. Here, we report the cDNA cloning of the corresponding oncogene, designated UFO, in allusion to the as yet unidentified function of its protein. Nucleotide sequence analysis of a 3116bp cDNA clone revealed a 2682-bp-long open reading frame capable of directing the synthesis of a 894 amino acid polypeptide. The predicted UFO protein exhibits characteristic features of a transmembrane receptor with associated tyrosine kinase activity. The UFO proto-oncogene maps to human chromosome 19q13.1 and is transcribed into two 5.0 kb and 3.2 kb mRNAs in human bone marrow and human tumor cell lines. The UFO locus is evolutionarily conserved between vertebrate species. A 4.0 kb mRNA of the murine UFO homolog is expressed in a variety of different mouse tissues. We thus have identified a novel element of the complex signaling network involved in the control of cell proliferation and differentiation.

  8. Fluoxetine potentiation of methylphenidate-induced gene regulation in striatal output pathways: potential role for 5-HT1B receptor.

    PubMed

    Van Waes, Vincent; Ehrlich, Sarah; Beverley, Joel A; Steiner, Heinz

    2015-02-01

    Drug combinations that include the psychostimulant methylphenidate plus a selective serotonin reuptake inhibitor (SSRI) such as fluoxetine are increasingly used in children and adolescents. For example, this combination is indicated in the treatment of attention-deficit/hyperactivity disorder and depression comorbidity and other mental disorders. Such co-exposure also occurs in patients on SSRIs who use methylphenidate as a cognitive enhancer. The neurobiological consequences of these drug combinations are poorly understood. Methylphenidate alone can produce gene regulation effects that mimic addiction-related gene regulation by cocaine, consistent with its moderate addiction liability. We have previously shown that combining SSRIs with methylphenidate potentiates methylphenidate-induced gene regulation in the striatum. The present study investigated which striatal output pathways are affected by the methylphenidate + fluoxetine combination, by assessing effects on pathway-specific neuropeptide markers, and which serotonin receptor subtypes may mediate these effects. Our results demonstrate that a 5-day repeated treatment with fluoxetine (5 mg/kg) potentiates methylphenidate (5 mg/kg)-induced expression of both dynorphin (direct pathway marker) and enkephalin (indirect pathway). These changes were accompanied by correlated increases in the expression of the 5-HT1B, but not 5-HT2C, serotonin receptor in the same striatal regions. A further study showed that the 5-HT1B receptor agonist CP94253 (3-10 mg/kg) mimics the fluoxetine potentiation of methylphenidate-induced gene regulation. These findings suggest a role for the 5-HT1B receptor in the fluoxetine effects on striatal gene regulation. Given that 5-HT1B receptors are known to facilitate addiction-related gene regulation and behavior, our results suggest that SSRIs may enhance the addiction liability of methylphenidate by increasing 5-HT1B receptor signaling.

  9. Neuroprotection by selective allosteric potentiators of the EP2 prostaglandin receptor

    PubMed Central

    Jiang, Jianxiong; Ganesh, Thota; Du, Yuhong; Thepchatri, Pahk; Rojas, Asheebo; Lewis, Iestyn; Kurtkaya, Serdar; Li, Lian; Qui, Min; Serrano, Geidy; Shaw, Renee; Sun, Aiming; Dingledine, Ray

    2010-01-01

    Activation of the Gαs-coupled EP2 receptor for prostaglandin E2 (PGE2) promotes cell survival in several models of tissue damage. To advance understanding of EP2 functions, we designed experiments to develop allosteric potentiators of this key prostaglandin receptor. Screens of 292,000 compounds identified 93 that at 20 μM (i) potentiated the cAMP response to a low concentration of PGE2 by > 50%; (ii) had no effect on EP4 or β2 adrenergic receptors, the cAMP assay itself, or the parent cell line; and (iii) increased the potency of PGE2 on EP2 receptors at least 3-fold. In aqueous solution, the active compounds are largely present as nanoparticles that appear to serve as active reservoirs for bioactive monomer. From 94 compounds synthesized or purchased, based on the modification of one hit compound, the most active increased the potency of PGE2 on EP2 receptors 4- to 5-fold at 10 to 20 μM and showed substantial neuroprotection in an excitotoxicity model. These small molecules represent previously undescribed allosteric modulators of a PGE2 receptor. Our results strongly reinforce the notion that activation of EP2 receptors by endogenous PGE2 released in a cell-injury setting is neuroprotective. PMID:20080612

  10. Computational studies of new potential antimalarial compounds--stereoelectronic complementarity with the receptor.

    PubMed

    Portela, César; Afonso, Carlos M M; Pinto, Madalena M M; Ramos, Maria João

    2003-09-01

    One of the most important pharmacological mechanisms of antimalarial action is the inhibition of the aggregation of hematin into hemozoin. We present a group of new potential antimalarial molecules for which we have performed a DFT study of their stereoelectronic properties. Additionally, the same calculations were carried out for the two putative drug receptors involved in the referred activity, i.e., hematin mu-oxo dimer and hemozoin. A complementarity between the structural and electronic profiles of the planned molecules and the receptors can be observed. A docking study of the new compounds in relation to the two putative receptors is also presented, providing a correlation with the defined electrostatic complementarity.

  11. Devil's Claw to Suppress Appetite—Ghrelin Receptor Modulation Potential of a Harpagophytum procumbens Root Extract

    PubMed Central

    Torres-Fuentes, Cristina; Theeuwes, Wessel F.; McMullen, Michael K.; McMullen, Anna K.; Dinan, Timothy G.; Cryan, John F.; Schellekens, Harriët

    2014-01-01

    Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a). Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek) stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits. PMID:25068823

  12. Devil's Claw to suppress appetite--ghrelin receptor modulation potential of a Harpagophytum procumbens root extract.

    PubMed

    Torres-Fuentes, Cristina; Theeuwes, Wessel F; McMullen, Michael K; McMullen, Anna K; Dinan, Timothy G; Cryan, John F; Schellekens, Harriët

    2014-01-01

    Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a). Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek) stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits. PMID:25068823

  13. Selective androgen receptor modulators in drug discovery: medicinal chemistry and therapeutic potential.

    PubMed

    Cadilla, Rodolfo; Turnbull, Philip

    2006-01-01

    Modulation of the androgen receptor has the potential to be an effective treatment for hypogonadism, andropause, and associated conditions such as sarcopenia, osteoporosis, benign prostatic hyperplasia, and sexual dysfunction. Side effects associated with classical anabolic steroid treatments have driven the quest for drugs that demonstrate improved therapeutic profiles. Novel, non-steroidal compounds that show tissue selective activity and improved pharmacokinetic properties have been developed. This review provides an overview of current advances in the development of selective androgen receptor modulators (SARMs).

  14. Estrogen-dependent up-regulation of TRPA1 and TRPV1 receptor proteins in the rat endometrium.

    PubMed

    Pohóczky, Krisztina; Kun, József; Szalontai, Bálint; Szőke, Éva; Sághy, Éva; Payrits, Maja; Kajtár, Béla; Kovács, Krisztina; Környei, József László; Garai, János; Garami, András; Perkecz, Anikó; Czeglédi, Levente; Helyes, Zsuzsanna

    2016-02-01

    Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors expressed predominantly in sensory nerves are activated by inflammatory stimuli and mediate inflammation and pain. Although they have been shown in the human endometrium, their regulation and function are unknown. Therefore, we investigated their estrogen- and progesterone-dependent alterations in the rat endometrium in comparison with the estrogen-regulated inflammatory cytokine macrophage migration inhibitory factor (MIF). Four-week-old (sexually immature) and four-month-old (sexually mature) female rats were treated with the non-selective estrogen receptor (ER) agonist diethylstilboestrol (DES), progesterone and their combination, or ovariectomized. RT-PCR and immunohistochemistry were performed to determine mRNA and protein expression levels respectively. Channel function was investigated with ratiometric [Ca(2+)]i measurement in cultured primary rat endometrial cells. Both TRP receptors and MIF were detected in the endometrium at mRNA and protein levels, and their localizations were similar. Immunostaining was observed in the immature epithelium, while stromal, glandular and epithelial positivity were observed in adults. Functionally active TRP receptor proteins were shown in endometrial cells by activation-induced calcium influx. In adults, Trpa1 and Trpv1 mRNA levels were significantly up-regulated after DES treatment. TRPA1 increased after every treatment, but TRPV1 remained unchanged following the combined treatment and ovariectomy. In immature rats, DES treatment resulted in increased mRNA expression of both channels and elevated TRPV1 immunopositivity. MIF expression changed in parallel with TRPA1/TRPV1 in most cases. DES up-regulated Trpa1, Trpv1 and Mif mRNA levels in endometrial cell cultures, but 17β-oestradiol having ERα-selective potency increased only the expression of Trpv1. We provide the first evidence for TRPA1/TRPV1 expression and their estrogen-induced up

  15. Pharmacological activation of CB1 receptor modulates long term potentiation by interfering with protein synthesis.

    PubMed

    Navakkode, Sheeja; Korte, Martin

    2014-04-01

    Cognitive impairment is one of the most important side effects associated with cannabis drug abuse, as well as the serious issue concerning the therapeutic use of cannabinoids. Cognitive impairments and neuropsychiatric symptoms are caused by early synaptic dysfunctions, such as loss of synaptic connections in different brain structures including the hippocampus, a region that is believed to play an important role in certain forms of learning and memory. We report here that metaplastic priming of synapses with a cannabinoid type 1 receptor (CB1 receptor) agonist, WIN55,212-2 (WIN55), significantly impaired long-term potentiation in the apical dendrites of CA1 pyramidal neurons. Interestingly, the CB1 receptor exerts its effect by altering the balance of protein synthesis machinery towards higher protein production. Therefore the activation of CB1 receptor, prior to strong tetanization, increased the propensity to produce new proteins. In addition, WIN55 priming resulted in the expression of late-LTP in a synaptic input that would have normally expressed early-LTP, thus confirming that WIN55 priming of LTP induces new synthesis of plasticity-related proteins. Furthermore, in addition to the effects on protein translation, WIN55 also induced synaptic deficits due to the ability of CB1 receptors to inhibit the release of acetylcholine, mediated by both muscarinic and nicotinic acetylcholine receptors. Taken together this supports the notion that the modulation of cholinergic activity by CB1 receptor activation is one mechanism that regulates the synthesis of plasticity-related proteins.

  16. β-Adrenergic receptor signaling and modulation of long-term potentiation in the mammalian hippocampus

    PubMed Central

    O'Dell, Thomas J.; Connor, Steven A.; Guglietta, Ryan

    2015-01-01

    Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the mammalian brain is norepinephrine (NE), which regulates multiple brain functions such as attention, perception, arousal, sleep, learning, and memory. The mammalian hippocampus receives noradrenergic innervation and hippocampal neurons express β-adrenergic receptors, which are known to play important roles in gating the induction of long-lasting forms of synaptic potentiation. These forms of long-term potentiation (LTP) are believed to importantly contribute to long-term storage of spatial and contextual memories in the brain. In this review, we highlight the contributions of noradrenergic signaling in general and β-adrenergic receptors in particular, toward modulating hippocampal LTP. We focus on the roles of NE and β-adrenergic receptors in altering the efficacies of specific signaling molecules such as NMDA and AMPA receptors, protein phosphatases, and translation initiation factors. Also, the roles of β-adrenergic receptors in regulating synaptic “tagging” and “capture” of LTP within synaptic networks of the hippocampus are reviewed. Understanding the molecular and cellular bases of noradrenergic signaling will enrich our grasp of how the brain makes new, enduring memories, and may shed light on credible strategies for improving mental health through treatment of specific disorders linked to perturbed memory processing and dysfunctional noradrenergic synaptic transmission. PMID:26286656

  17. Metabotropic glutamate receptors are required for the induction of long-term potentiation

    NASA Technical Reports Server (NTRS)

    Zheng, F.; Gallagher, J. P.

    1992-01-01

    Recent observations have led to the suggestion that the metabotropic glutamate receptor may play a role in the induction or maintenance of long-term potentiation (LTP). However, experimental evidence supporting a role for this receptor in the induction of LTP is still inconclusive and controversial. Here we report that, in rat dorsolateral septal nucleus (DLSN) neurons, which have the highest density of metabotropic receptors and show functional responses, the induction of LTP is not blocked by the NMDA receptor antagonist 2-amino-5-phosphonovalerate, but is blocked by two putative metabotropic glutamate receptor antagonists, L-2-amino-3-phosphonopropionic acid and L-2-amino-4-phosphonobutyrate. Furthermore, superfusion of (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid, a selective metabotropic glutamate agonist, resulted in a long-lasting potentiation of synaptic transmission similar to that induced by tetanic stimuli. Our results demonstrated that activation of postsynaptic metabotropic receptors is both necessary and sufficient for the induction of LTP in the DLSN, and we suggest that such a mechanism may be important at other CNS synapses.

  18. Transient Receptor Potential Ankyrin 1 (TRPA1) Channel and Neurogenic Inflammation in Pathogenesis of Asthma

    PubMed Central

    Yang, Hang; Li, ShuZhuang

    2016-01-01

    Asthma is characterized by airway inflammation, airway obstruction, and airway hyperresponsiveness (AHR), and it affects 300 million people worldwide. However, our current understanding of the molecular mechanisms that underlie asthma remains limited. Recent studies have suggested that transient receptor potential ankyrin 1 (TRPA1), one of the transient receptor potential cation channels, may be involved in airway inflammation in asthma. The present review discusses the relationship between TRPA1 and neurogenic inflammation in asthma, hoping to enhance our understanding of the mechanisms of airway inflammation in asthma. PMID:27539812

  19. NPY receptors as potential targets for anti-obesity drug development

    PubMed Central

    Yulyaningsih, Ernie; Zhang, Lei; Herzog, Herbert; Sainsbury, Amanda

    2011-01-01

    The neuropeptide Y system has proven to be one of the most important regulators of feeding behaviour and energy homeostasis, thus presenting great potential as a therapeutic target for the treatment of disorders such as obesity and at the other extreme, anorexia. Due to the initial lack of pharmacological tools that are active in vivo, functions of the different Y receptors have been mainly studied in knockout and transgenic mouse models. However, over recent years various Y receptor selective peptidic and non-peptidic agonists and antagonists have been developed and tested. Their therapeutic potential in relation to treating obesity and other disorders of energy homeostasis is discussed in this review. PMID:21545413

  20. Transient Receptor Potential Ankyrin 1 (TRPA1) Channel and Neurogenic Inflammation in Pathogenesis of Asthma.

    PubMed

    Yang, Hang; Li, ShuZhuang

    2016-01-01

    Asthma is characterized by airway inflammation, airway obstruction, and airway hyperresponsiveness (AHR), and it affects 300 million people worldwide. However, our current understanding of the molecular mechanisms that underlie asthma remains limited. Recent studies have suggested that transient receptor potential ankyrin 1 (TRPA1), one of the transient receptor potential cation channels, may be involved in airway inflammation in asthma. The present review discusses the relationship between TRPA1 and neurogenic inflammation in asthma, hoping to enhance our understanding of the mechanisms of airway inflammation in asthma. PMID:27539812

  1. ETA receptor blockade potentiates the bronchoconstrictor response to ET-1 in the guinea pig airway.

    PubMed

    Polakowski, J S; Opgenorth, T J; Pollock, D M

    1996-08-01

    The effect of ETA receptor blockade on the bronchopulmonary response to endothelin-1 was determined in the airway of the anesthetized, spontaneously breathing guinea pig. Endothelin-1 administered as an aerosol increased lung resistance and decreased dynamic lung compliance. Delivery of the ETA receptor antagonist, FR139317, 5 min prior to giving endothelin-1 greatly potentiated these changes. A lower dose of endothelin-1 that had no effect on resistance or compliance produced large and significant changes when pretreated with FR139317. In contrast, aerosolized FR139317 had no effect on the bronchopulmonary response to intravenously administered endothelin-1. These data suggest a non-contractile function of ETA receptors accessible from the airways that serve to buffer the constrictor effects of non-ETA receptors.

  2. Role and therapeutic potential of G-protein coupled receptors in breast cancer progression and metastases

    PubMed Central

    Singh, Anukriti; Nunes, Jessica J.; Ateeq, Bushra

    2015-01-01

    G-protein-coupled receptors (GPCRs) comprise a large family of cell-surface receptors, which have recently emerged as key players in tumorigenesis, angiogenesis and metastasis. In this review, we discussed our current understanding of the many roles played by GPCRs in general, and particularly Angiotensin II type I receptor (AGTR1), a member of the seven-transmembrane-spanning G-protein coupled receptor superfamily, and its significance in breast cancer progression and metastasis. We have also discussed different strategies for targeting AGTR1, and its ligand Angiotension II (Ang II), which might unravel unique opportunities for breast cancer prevention and treatment. For example, AGTR1 blockers (ARBs) which are already in clinical use for treating hypertension, merit further investigation as a therapeutic strategy for AGTR1-positive cancer patients and may have the potential to prevent Ang II-AGTR1 signalling mediated cancer pathogenesis and metastases. PMID:25981295

  3. Positive selection moments identify potential functional residues in human olfactory receptors

    NASA Technical Reports Server (NTRS)

    Singer, M. S.; Weisinger-Lewin, Y.; Lancet, D.; Shepherd, G. M.

    1996-01-01

    Correlated mutation analysis and molecular models of olfactory receptors have provided evidence that residues in the transmembrane domains form a binding pocket for odor ligands. As an independent test of these results, we have calculated positive selection moments for the alpha-helical sixth transmembrane domain (TM6) of human olfactory receptors. The moments can be used to identify residues that have been preferentially affected by positive selection and are thus likely to interact with odor ligands. The results suggest that residue 622, which is commonly a serine or threonine, could form critical H-bonds. In some receptors a dual-serine subsite, formed by residues 622 and 625, could bind hydroxyl determinants on odor ligands. The potential importance of these residues is further supported by site-directed mutagenesis in the beta-adrenergic receptor. The findings should be of practical value for future physiological studies, binding assays, and site-directed mutagenesis.

  4. Potential ligand-binding residues in rat olfactory receptors identified by correlated mutation analysis

    NASA Technical Reports Server (NTRS)

    Singer, M. S.; Oliveira, L.; Vriend, G.; Shepherd, G. M.

    1995-01-01

    A family of G-protein-coupled receptors is believed to mediate the recognition of odor molecules. In order to identify potential ligand-binding residues, we have applied correlated mutation analysis to receptor sequences from the rat. This method identifies pairs of sequence positions where residues remain conserved or mutate in tandem, thereby suggesting structural or functional importance. The analysis supported molecular modeling studies in suggesting several residues in positions that were consistent with ligand-binding function. Two of these positions, dominated by histidine residues, may play important roles in ligand binding and could confer broad specificity to mammalian odor receptors. The presence of positive (overdominant) selection at some of the identified positions provides additional evidence for roles in ligand binding. Higher-order groups of correlated residues were also observed. Each group may interact with an individual ligand determinant, and combinations of these groups may provide a multi-dimensional mechanism for receptor diversity.

  5. GABAA receptor modulation by piperine and a non-TRPV1 activating derivative☆

    PubMed Central

    Khom, Sophia; Strommer, Barbara; Schöffmann, Angela; Hintersteiner, Juliane; Baburin, Igor; Erker, Thomas; Schwarz, Thomas; Schwarzer, Christoph; Zaugg, Janine; Hamburger, Matthias; Hering, Steffen

    2013-01-01

    The action of piperine (the pungent component of pepper) and its derivative SCT-66 ((2E,4E)-5-(1,3-benzodioxol-5-yl))-N,N-diisobutyl-2,4-pentadienamide) on different gamma-aminobutyric acid (GABA) type A (GABAA) receptors, transient-receptor-potential-vanilloid-1 (TRPV1) receptors and behavioural effects were investigated. GABAA receptor subtypes and TRPV1 receptors were expressed in Xenopus laevis oocytes. Modulation of GABA-induced chloride currents (IGABA) by piperine and SCT-66 and activation of TRPV1 was studied using the two-microelectrode-voltage-clamp technique and fast perfusion. Their effects on explorative behaviour, thermoregulation and seizure threshold were analysed in mice. Piperine acted with similar potency on all GABAA receptor subtypes (EC50 range: 42.8 ± 7.6 μM (α2β2)–59.6 ± 12.3 μM (α3β2)). IGABA modulation by piperine did not require the presence of a γ2S-subunit, suggesting a binding site involving only α and β subunits. IGABA activation was slightly more efficacious on receptors formed from β2/3 subunits (maximal IGABA stimulation through α1β3 receptors: 332 ± 64% and α1β2: 271 ± 36% vs. α1β1: 171 ± 22%, p < 0.05) and α3-subunits (α3β2: 375 ± 51% vs. α5β2:136 ± 22%, p < 0.05). Replacing the piperidine ring by a N,N-diisobutyl residue (SCT-66) prevents interactions with TRPV1 and simultaneously increases the potency and efficiency of GABAA receptor modulation. SCT-66 displayed greater efficacy on GABAA receptors than piperine, with different subunit-dependence. Both compounds induced anxiolytic, anticonvulsant effects and reduced locomotor activity; however, SCT-66 induced stronger anxiolysis without decreasing body temperature and without the proconvulsive effects of TRPV1 activation and thus may serve as a scaffold for the development of novel GABAA receptor modulators. PMID:23623790

  6. Novel drugs that target the estrogen-related receptor alpha: their therapeutic potential in breast cancer

    PubMed Central

    May, Felicity EB

    2014-01-01

    The incidence of breast cancer continues to rise: 1.7 million women were diagnosed with and 521,000 women died from breast cancer in 2012. This review considers first current treatment options: surgery; radiotherapy; and systemic endocrine, anti-biological, and cytotoxic therapies. Clinical management includes prevention, early detection by screening, treatment with curative intent, management of chronic disease, and palliative control of advanced breast cancer. Next, the potential of novel drugs that target DNA repair, growth factor dependence, intracellular and intercellular signal transduction, and cell cycle are considered. Estrogen-related receptor alpha has attracted attention as a therapeutic target in triple-negative breast cancers with de novo resistance to, and in breast cancers with acquired resistance to, endocrine therapies such as antiestrogens and aromatase inhibitors. Estrogen-related receptor alpha is an orphan receptor and transcription factor. Its activity is regulated by coregulator proteins and posttranslational modification. It is an energy sensor that controls adaptation to energy demand and may facilitate glycolytic metabolism and mitochondrial oxidative respiration in breast cancer cells. Estrogen-related receptor alpha increases breast cancer cell migration, proliferation, and tumor development. It is expressed at high levels in estrogen receptor-negative tumors, and is proposed to activate estrogen-responsive genes in endocrine-resistant tumors. The structures and functions of the ligand-binding domains of estrogen receptor alpha and estrogen-related receptor alpha, their ability to bind estrogens, phytoestrogens, and synthetic ligands, and the effects of ligand agonists, antagonists, and inverse agonists on biological activity, are evaluated. Synthetic ligands of estrogen-related receptor alpha have activity in preclinical models of metabolic disorders, diabetes, osteoporosis, and oncology. The clinical settings in which these novel

  7. Mechanisms intrinsic to 5-HT2B receptor-induced potentiation of NMDA receptor responses in frog motoneurones.

    PubMed

    Holohean, Alice M; Hackman, John C

    2004-10-01

    In the presence of NMDA receptor open-channel blockers [Mg(2+); (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801); 1-amino-3,5-dimethyladamantane (memantine)] and TTX, high concentrations (30-100 microm) of either 5-hydroxytryptamine (5-HT) or alpha-methyl-5-hydroxytryptamine (alpha-Me-5-HT) significantly potentiated NMDA-induced depolarizations of frog spinal cord motoneurones. Potentiation was blocked by LY-53,857 (10-30 microm), SB 206553 (10 microm), and SB 204741 (30 microm), but not by spiroxatrine (10 microm), WAY 100,635 (1-30 microm), ketanserin (10 microm), RS 102221 (10 microm), or RS 39604 (10-20 microm). Therefore, alpha-Me-5-HT's facilitatory effects appear to involve 5-HT(2B) receptors. These effects were G-protein dependent as they were prevented by prior treatment with guanylyl-5'-imidodiphosphate (GMP-PNP, 100 microm) and H-Arg-Pro-Lys-Pro-Gln-Gln-D-Trp-Phe-D-Trp-D-Trp-Met-NH(2) (GP antagonist 2A, 3-6 microm), but not by pertussis toxin (PTX, 3-6 ng ml(-1), 48 h preincubation). This potentiation was not reduced by protein kinase C inhibition with staurosporine (2.0 microm), U73122 (10 microm) or N-(2-aminoethyl)-5-isoquinolinesulfonamide HCl (H9) (77 microm) or by intracellular Ca(2+) depletion with thapsigargin (0.1 microm) (which inhibits Ca(2+)/ATPase). Exposure of the spinal cord to the L-type Ca(2+) channel blockers nifedipine (10 microm), KN-62 (5 microm) or gallopamil (100 microm) eliminated alpha-Me-5-HT's effects. The calmodulin antagonist N-(6-aminohexyl)-5-chloro-1-naphtalenesulfonamide (W7) (100 microm) diminished the potentiation. However, the calcium/calmodulin-dependent protein kinase II (CaM Kinase II) blocker KN-93 (10 microm) did not block the 5-HT enhancement of the NMDA responses. In summary, activation of 5-HT(2B) receptors by alpha-Me-5-HT facilitates NMDA-depolarizations of frog motoneurones via a G-protein, a rise in [Ca(2+)](i) from the entry of extracellular Ca(2+) through L-type Ca(2

  8. Temperature-sensitive transient receptor potential channels in corneal tissue layers and cells.

    PubMed

    Mergler, Stefan; Valtink, Monika; Takayoshi, Sumioka; Okada, Yuka; Miyajima, Masayasu; Saika, Shizuya; Reinach, Peter S

    2014-01-01

    We here provide a brief summary of the characteristics of transient receptor potential channels (TRPs) identified in corneal tissue layers and cells. In general, TRPs are nonselective cation channels which are Ca(2+) permeable. Most TRPs serve as thermosensitive molecular sensors (thermo-TRPs). Based on their functional importance, the possibilities are described for drug-targeting TRP activity in a clinical setting. TRPs are expressed in various tissues of the eye including both human corneal epithelial and endothelial layers as well as stromal fibroblasts and stromal nerve fibers. TRP vanilloid type 1 (TRPV1) heat receptor, also known as capsaicin receptor, along with TRP melastatin type 8 (TRPM8) cold receptor, which is also known as menthol receptor, are prototypes of the thermo-TRP family. The TRPV1 functional channel is the most investigated TRP channel in these tissues, owing to its contribution to maintaining tissue homeostasis as well as eliciting wound healing responses to injury. Other thermo-TRP family members identified in these tissues are TRPV2, 3 and 4. Finally, there is the TRP ankyrin type 1 (TRPA1) cold receptor. All of these thermo-TRPs can be activated within specific temperature ranges and transduce such inputs into chemical and electrical signals. Although several recent studies have begun to unravel complex roles for thermo-TRPs such as TRPV1 in corneal layers and resident cells, additional studies are needed to further elucidate their roles in health and disease.

  9. Enhanced AMPA Receptor Function Promotes Cerebellar Long-Term Depression Rather than Potentiation

    ERIC Educational Resources Information Center

    van Beugen, Boeke J.; Qiao, Xin; Simmons, Dana H.; De Zeeuw, Chris I.; Hansel, Christian

    2014-01-01

    Ampakines are allosteric modulators of AMPA receptors that facilitate hippocampal long-term potentiation (LTP) and learning, and have been considered for the treatment of cognition and memory deficits. Here, we show that the ampakine CX546 raises the amplitude and slows the decay time of excitatory postsynaptic currents (EPSCs) at cerebellar…

  10. GLUCOCORTICOID RECEPTOR REGULATION IN THE RAT EMBRYO: A POTENTIAL SITE FOR DEVELOPMENTAL TOXICITY?

    EPA Science Inventory

    Glucocorticoid receptor regulation in the rat embryo: a potential site for developmental toxicity?

    Ghosh B, Wood CR, Held GA, Abbott BD, Lau C.

    National Research Council, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.

  11. Vascular endothelial growth factor receptors: Molecular mechanisms of activation and therapeutic potentials

    PubMed Central

    Rahimi, Nader

    2006-01-01

    Angiogenesis-associated eye diseases are among the most common cause of blindness in the United States and worldwide. Recent advances in the development of angiogenesis-based therapies for treatment of angiogenesis-associated diseases have provided new hope in a wide variety of human diseases ranging from eye diseases to cancer. One group of growth factor receptors critically implicated in angiogenesis is vascular endothelial growth factor receptors (VEGFR), a subfamily of receptor tyrosine kinases (RTKs). VEGFR-1 and VEGFR-2 are closely related receptor tyrosine kinases and have both common and specific ligands. VEGFR-1 is a kinase-impaired RTK and its kinase activity is suppressed by a single amino acid substitution in its kinase domain and by its carboxyl terminus. VEGFR-2 is highly active kinase, stimulates a variety of signaling pathways and broad biological responses in endothelial cells. The mechanisms that govern VEGFR-2 activation, its ability to recruit signaling proteins and to undergo downregulation are highly regulated by phosphorylation activation loop tyrosines and its carboxyl terminus. Despite their differential potentials to undergo tyrosine phosphorylation and kinase activation, both VEGFR-1 and VEGFR-2 are required for normal embryonic development and pathological angiogenesis. VEGFR-1 regulates angiogenesis by mechanisms that involve ligand trapping, receptor homodimerization and heterodimerization. This review highlights recent insights into the mechanism of activation of VEGFR-1 and VEGFR-2, and focuses on the signaling pathways employed by VEGFR-1 and VEGFR-2 that regulate angiogenesis and their therapeutic potentials in angiogenesis-associated diseases. PMID:16713597

  12. Antihistamine terfenadine potentiates NMDA receptor-mediated calcium influx, oxygen radical formation, and neuronal death.

    PubMed

    Díaz-Trelles, R; Novelli, A; Vega, J A; Marini, A; Fernández-Sánchez, M T

    2000-10-13

    We previously reported that the histamine H1 receptor antagonist terfenadine enhances the excitotoxic response to N-methyl-D-aspartate (NMDA) receptor agonists in cerebellar neurons. Here we investigated whether this unexpected action of terfenadine relates to its antihistamine activity, and which specific events in the signal cascade coupled to NMDA receptors are affected by terfenadine. Low concentrations of NMDA (100 microM) or glutamate (15 microM) that were only slightly (<20%) toxic when added alone, caused extensive cell death in cultures pre-exposed to terfenadine (5 microM) for 5 h. Terfenadine potentiation of NMDA receptor response was mimicked by other H1 antagonists, including chlorpheniramine (25 microM), oxatomide (20 microM), and triprolidine (50 microM), was prevented by histamine (1 mM), and did not require RNA synthesis. Terfenadine increased NMDA-mediated intracellular calcium and cGMP synthesis by approximately 2.4 and 4 fold respectively. NMDA receptor-induced cell death in terfenadine-treated neurons was associated with a massive production of hydrogen peroxides, and was significantly inhibited by the application of either (+)-alpha-tocopherol (200 microM) or the endogenous antioxidant melatonin (200 microM) 15 min before or up to 30 min after receptor stimulation. This operational time window suggests that an enduring production of reactive oxygen species is critical for terfenadine-induced NMDA receptor-mediated neurodegeneration, and strengthens the importance of antioxidants for the treatment of excitotoxic injury. Our results also provide direct evidence for antihistamine drugs enhancing the transduction signaling activated by NMDA receptors in cerebellar neurons.

  13. The 5-HT7 receptor as a potential target for treating drug and alcohol abuse.

    PubMed

    Hauser, Sheketha R; Hedlund, Peter B; Roberts, Amanda J; Sari, Youssef; Bell, Richard L; Engleman, Eric A

    2014-01-01

    Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed-including the mesocorticolimbic dopamine (MCL-DA) system and the extended amygdala. The serotonin (5-HT) neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT7 receptor as a novel target for treating addiction. PMID:25628528

  14. The 5-HT7 receptor as a potential target for treating drug and alcohol abuse

    PubMed Central

    Hauser, Sheketha R.; Hedlund, Peter B.; Roberts, Amanda J.; Sari, Youssef; Bell, Richard L.; Engleman, Eric A.

    2015-01-01

    Alcohol and drug abuse take a large toll on society and affected individuals. However, very few effective treatments are currently available to treat alcohol and drug addiction. Basic and clinical research has begun to provide some insights into the underlying neurobiological systems involved in the addiction process. Several neurotransmitter pathways have been implicated and distinct reward neurocircuitry have been proposed—including the mesocorticolimbic dopamine (MCL-DA) system and the extended amygdala. The serotonin (5-HT) neurotransmitter system is of particular interest and multiple 5-HT receptors are thought to play significant roles in alcohol and drug self-administration and the development of drug dependence. Among the 5-HT receptors, the 5-HT7 receptor is currently undergoing characterization as a potential target for the treatment of several psychiatric disorders. Although this receptor has received only limited research regarding addictive behaviors, aspects of its neuroanatomical, biochemical, physiological, pharmacological, and behavioral profiles suggest that it could play a key role in the addiction process. For instance, genomic studies in humans have suggested a link between variants in the gene encoding the 5-HT7 receptor and alcoholism. Recent behavioral testing using high-affinity antagonists in mice and preliminary tests with alcohol-preferring rats suggest that this receptor could mediate alcohol consumption and/or reinforcement and play a role in seeking/craving behavior. Interest in the development of new and more selective pharmacological agents for this receptor will aid in examining the 5-HT7 receptor as a novel target for treating addiction. PMID:25628528

  15. Potential of the cannabinoid CB(2) receptor as a pharmacological target against inflammation in Parkinson's disease.

    PubMed

    Gómez-Gálvez, Yolanda; Palomo-Garo, Cristina; Fernández-Ruiz, Javier; García, Concepción

    2016-01-01

    Inflammation is an important pathogenic factor in Parkinson's disease (PD), so that it can contribute to kill dopaminergic neurons of the substantia nigra and to enhance the dopaminergic denervation of the striatum. The cannabinoid type-2 (CB2) receptor has been investigated as a potential anti-inflammatory and neuroprotective target in different neurodegenerative disorders, but still limited evidence has been collected in PD. Here, we show for the first time that CB2 receptors are elevated in microglial cells recruited and activated at lesioned sites in the substantia nigra of PD patients compared to control subjects. Parkinsonian inflammation can be reproduced experimentally in rodents by intrastriatal injections of lipopolysaccharide (LPS) which, through an intense activation of glial elements and peripheral infiltration, provokes a rapid deterioration of the striatum that may extend to the substantia nigra too. Using this experimental model, we recently described a much more intense deterioration of tyrosine hydroxylase (TH)-containing nigral neurons in CB2 receptor-deficient mice compared to wild-type animals, supporting a potential neuroprotective role for this receptor. In the present study, we further explored this issue. First, we found elevated levels of the CB2 receptor measured by qRT-PCR in the striatum and substantia nigra of LPS-lesioned mice, as well as an increase in the immunostaining for this receptor in the LPS-lesioned striatum. Second, we found a significant increase in CD68 immunostaining, which serve to identify activated microglia and also infiltrated peripheral macrophages, in these brain structures in response to LPS insult, which was much more intense in CB2 receptor-deficient mice in the case of the substantia nigra. Next, we observed that the activation of CB2 receptors with a selective agonist (HU-308) reversed LPS-induced elevation of CD68 immunostaining in the striatum and the parallel reduction in TH immunostaining. Lastly, we

  16. CPEB3 Deficiency Elevates TRPV1 Expression in Dorsal Root Ganglia Neurons to Potentiate Thermosensation

    PubMed Central

    Chen, Chih-Cheng; Huang, Yi-Shuian

    2016-01-01

    Cytoplasmic polyadenylation element binding protein 3 (CPEB3) is a sequence-specific RNA-binding protein that downregulates translation of multiple plasticity-related proteins (PRPs) at the glutamatergic synapses. Activity-induced synthesis of PRPs maintains long-lasting synaptic changes that are critical for memory consolidation and chronic pain manifestation. CPEB3-knockout (KO) mice show aberrant hippocampus-related plasticity and memory, so we investigated whether CPEB3 might have a role in nociception-associated plasticity. CPEB3 is widely expressed in the brain and peripheral afferent sensory neurons. CPEB3-KO mice with normal mechanosensation showed hypersensitivity to noxious heat. In the complete Freund's adjuvant (CFA)-induced inflammatory pain model, CPEB3-KO animals showed normal thermal hyperalgesia and transiently enhanced mechanical hyperalgesia. Translation of transient receptor potential vanilloid 1 (TRPV1) RNA was suppressed by CPEB3 in dorsal root ganglia (DRG), whereas CFA-induced inflammation reversed this inhibition. Moreover, CPEB3/TRPV1 double-KO mice behaved like TRPV1-KO mice, with severely impaired thermosensation and thermal hyperalgesia. An enhanced thermal response was recapitulated in non-inflamed but not inflamed conditional-KO mice, with cpeb3 gene ablated mostly but not completely, in small-diameter nociceptive DRG neurons. CPEB3-regulated translation of TRPV1 RNA may play a role in fine-tuning thermal sensitivity of nociceptors. PMID:26915043

  17. Structure-activity relationships of vanilloid receptor agonists for arteriolar TRPV1

    PubMed Central

    Czikora, Á; Lizanecz, E; Bakó, P; Rutkai, I; Ruzsnavszky, F; Magyar, J; Pórszász, R; Kark, T; Facskó, A; Papp, Z; Édes, I; Tóth, A

    2012-01-01

    BACKGROUND AND PURPOSE The transient receptor potential vanilloid 1 (TRPV1) plays a role in the activation of sensory neurons by various painful stimuli and is a therapeutic target. However, functional TRPV1 that affect microvascular diameter are also expressed in peripheral arteries and we attempted to characterize this receptor. EXPERIMENTAL APPROACH Sensory TRPV1 activation was measured in rats by use of an eye wiping assay. Arteriolar TRPV1-mediated smooth muscle specific responses (arteriolar diameter, changes in intracellular Ca2+) were determined in isolated, pressurized skeletal muscle arterioles obtained from the rat and wild-type or TRPV1−/− mice and in canine isolated smooth muscle cells. The vascular pharmacology of the TRPV1 agonists (potency, efficacy, kinetics of action and receptor desensitization) was determined in rat isolated skeletal muscle arteries. KEY RESULTS Capsaicin evoked a constrictor response in isolated arteries similar to that mediated by noradrenaline, this was absent in arteries from TRPV1 knockout mice and competitively inhibited by TRPV1 antagonist AMG9810. Capsaicin increased intracellular Ca2+ in the arteriolar wall and in isolated smooth muscle cells. The TRPV1 agonists evoked similar vascular constrictions (MSK-195 and JYL-79) or were without effect (resiniferatoxin and JYL-273), although all increased the number of responses (sensory activation) in the eye wiping assay. Maximal doses of all agonists induced complete desensitization (tachyphylaxis) of arteriolar TRPV1 (with the exception of capsaicin). Responses to the partial agonist JYL-1511 suggested 10% TRPV1 activation is sufficient to evoke vascular tachyphylaxis without sensory activation. CONCLUSIONS AND IMPLICATIONS Arteriolar TRPV1 have different pharmacological properties from those located on sensory neurons in the rat. PMID:21883148

  18. [Upregulation of P2X3 receptors in dorsal root ganglion of TRPV1 knockout female mice].

    PubMed

    Fang, Xiao; Shi, Xiao-Han; Huang, Li-Bin; Rong, Wei-Fang; Ma, Bei

    2014-08-25

    The study was aimed to investigate the changes in mechanical pain threshold in the condition of chronic inflammatory pain after transient receptor potential vanilloid 1 (TRPV1) gene was knockout. Hind-paw intraplantar injection of complete freund's adjuvant (CFA, 20 μL) produced peripheral inflammation in wild-type and TRPV1 knockout female mice. The mechanical pain thresholds were measured during the 8 days after injection and pre-injection by using Von-Frey hair. Nine days after injection, mice were killed and the differences of expression of c-Fos and P2X3 receptor in the dorsal root ganglia (DRG) and spinal cord dorsal horn were examined by Western blotting between the two groups. Compared with that in wild-type mice, the mechanical pain threshold was increased significantly in TRPV1 knockout mice (P < 0.05); 3 days after CFA injection, the baseline mechanical pain threshold in the TRPV1 knockout mice group was significantly higher than that in the wild-type mice group (P < 0.05); The result of Western blotting showed that the expression of c-Fos protein both in DRG and spinal cord dorsal horn of TRPV1 knockout mice group was decreased significantly compared with that in wild-type mice group (P < 0.01, P < 0.05), while the expression of P2X3 receptor in DRG of TRPV1 knockout mice group was increased significantly compared with that in wild-type mice group (P < 0.05). Our findings indicate that TRPV1 may influence the peripheral mechanical pain threshold by mediating the expression of c-Fos protein both in DRG and spinal cord dorsal horn and changing the expression of P2X3 receptor in DRG.

  19. Estrogen Receptors Alpha (ERα) and Beta (ERβ): Subtype-Selective Ligands and Clinical Potential

    PubMed Central

    Paterni, Ilaria; Granchi, Carlotta; Katzenellenbogen, John A.; Minutolo, Filippo

    2014-01-01

    Estrogen receptors alpha (ERα) and beta (ERβ) are nuclear transcription factors that are involved in the regulation of many complex physiological processes in humans. Modulation of these receptors by prospective therapeutic agents is currently being considered for prevention and treatment of a wide variety of pathological conditions, such as, cancer, metabolic and cardiovascular diseases, neurodegeneration, inflammation, and osteoporosis. This review provides an overview and update of compounds that have been recently reported as modulators of ERs, with a particular focus on their potential clinical applications. PMID:24971815

  20. In Vivo Quantification of Tumor Receptor Binding Potential with Dual-Reporter Molecular Imaging

    PubMed Central

    Tichauer, Kenneth M.; Samkoe, Kimberley S.; Sexton, Kristian J.; Hextrum, Shannon K.; Yang, Harold H.; Klubben, W. Spencer; Gunn, Jason R.; Hasan, Tayyaba; Pogue, Brian W.

    2012-01-01

    Purpose Receptor availability represents a key component of current cancer management. However, no approaches have been adopted to do this clinically, and the current standard of care is invasive tissue biopsy. A dual-reporter methodology capable of quantifying available receptor binding potential of tumors in vivo within a clinically relevant time scale is presented. Procedures To test the methodology, a fluorescence imaging-based adaptation was validated against ex vivo and in vitro measures of epidermal growth factor receptor (EGFR) binding potential in four tumor lines in mice, each line expected to express a different level of EGFR. Results A strong correlation was observed between in vivo and ex vivo measures of binding potential for all tumor lines (r=0.99, p<0.01, slope=1.80±0.48, and intercept=−0.58±0.84) and between in vivo and in vitro for the three lines expressing the least amount of EGFR (r=0.99, p<0.01, slope=0.64±0.32, and intercept=0.47±0.51). Conclusions By providing a fast and robust measure of receptor density in tumors, the presented methodology has powerful implications for improving choices in cancer intervention, evaluation, and monitoring, and can be scaled to the clinic with an imaging modality like SPECT. PMID:22203241

  1. Retinoic acid and retinoid receptors: potential chemopreventive and therapeutic role in cervical cancer.

    PubMed

    Abu, Jafaru; Batuwangala, Madu; Herbert, Karl; Symonds, Paul

    2005-09-01

    Retinoids are natural and synthetic derivatives of vitamin A, which can be obtained from animal products (milk, liver, beef, fish oils, and eggs) and vegetables (carrots, mangos, sweet potatoes, and spinach). Retinoids regulate various important cellular functions in the body through specific nuclear retinoic-acid receptors and retinoid-X receptors, which are encoded by separate genes. Retinoic-acid receptors specifically bind tretinoin and alitretinoin, whereas retinoid-X receptors bind only alitretinoin. Retinoids have long been established as crucial for several essential life processes-healthy growth, vision, maintenance of tissues, reproduction, metabolism, tissue differentiation (normal, premalignant cells, and malignant cells), haemopoiesis, bone development, spermatogenesis, embryogenesis, and overall survival. Therefore, deficiency of vitamin A can lead to various unwanted biological effects. Several experimental and epidemiological studies have shown the antiproliferative activity of retinoids and their potential use in cancer treatment and chemoprevention. Emerging clinical trials have shown the chemotherapeutic and chemopreventive potential of retinoids in cancerous and precancerous conditions of the uterine cervix. In this review, we explore the potential chemopreventive and therapeutic roles of retinoids in preinvasive and invasive cervical neoplasia.

  2. Neuropeptide receptors as potential drug targets in the treatment of inflammatory conditions

    PubMed Central

    Pintér, Erika; Pozsgai, Gábor; Hajna, Zsófia; Helyes, Zsuzsanna; Szolcsányi, János

    2014-01-01

    Cross-talk between the nervous, endocrine and immune systems exists via regulator molecules, such as neuropeptides, hormones and cytokines. A number of neuropeptides have been implicated in the genesis of inflammation, such as tachykinins and calcitonin gene-related peptide. Development of their receptor antagonists could be a promising approach to anti-inflammatory pharmacotherapy. Anti-inflammatory neuropeptides, such as vasoactive intestinal peptide, pituitary adenylate cyclase-activating polypeptide, α-melanocyte-stimulating hormone, urocortin, adrenomedullin, somatostatin, cortistatin, ghrelin, galanin and opioid peptides, are also released and act on their own receptors on the neurons as well as on different inflammatory and immune cells. The aim of the present review is to summarize the most prominent data of preclinical animal studies concerning the main pharmacological effects of ligands acting on the neuropeptide receptors. Promising therapeutic impacts of these compounds as potential candidates for the development of novel types of anti-inflammatory drugs are also discussed. PMID:23432438

  3. Metabotropic glutamate receptors: potential drug targets for the treatment of schizophrenia.

    PubMed

    Chavez-Noriega, Laura E; Schaffhauser, Hervé; Campbell, Una C

    2002-06-01

    Schizophrenia is a debilitating chronic psychiatric illness affecting 1% of the population. The cardinal features of schizophrenia are positive symptoms (thought disorder, hallucinations, catatonic behavior), negative symptoms (social withdrawal, anhedonia, apathy) and cognitive impairment. Although progress in elucidating the aetiology of schizophrenia has been slow, new insights on the neurochemical and neurophysiological mechanisms underlying the pathophysiology of this illness are beginning to emerge. The glutamate/N-methyl-D-aspartate (NMDA) hypofunction hypothesis of schizophrenia is supported by observations that administration of NMDA glutamate receptor antagonists such as phencyclidine (PCP) or ketamine induces psychosis in humans; moreover, decreased levels of glutamate and changes in several markers of glutamatergic function occur in schizophrenic brain. Administration of PCP or ketamine to rodents elicits an increase in locomotion and stereotypy accompanied by an increase in glutamate efflux in several brain regions. Systemic administration of group II metabotropic glutamate (mGlu) receptor agonists suppresses PCP-induced behavioral effects and the increase in glutamate efflux. Activation of group II mGlu receptors (mGlu2 and mGlu3) decreases glutamate release from presynaptic nerve terminals, suggesting that group II mGlu receptor agonists may be beneficial in the treatment of schizophrenia. In addition, pharmacological manipulations that enhance NMDA function may be efficacious antipsychotics. Selective activation of mGlu5 receptors significantly potentiates NMDA-induced responses, supporting this novel approach for the treatment of schizophrenia. The glutamate hypothesis of schizophrenia predicts that agents that restore the balance in glutamatergic neurotransmission will ameliorate the symptomatology associated with this illness. Development of potent, efficacious, systemically active drugs will help to address the antipsychotic potential of these

  4. Nuclear receptors: potential biomarkers for assessing physiological functions of soy proteins and phytoestrogens.

    PubMed

    Xiao, Chao Wu; Wood, Carla; Gilani, G Sarwar

    2006-01-01

    Soy consumption is associated with decreased incidence of chronic diseases, including cardiovascular diseases, atherosclerosis, diabetes, osteoporosis, and certain types of cancers. However, consumption of high amounts of soy isoflavones may adversely influence endocrine functions, such as thyroid function and reproductive performance, because of their structural similarity to endogenous estrogens. Nuclear receptors are a group of transcription factors that play critical roles in the regulation of gene expression and physiological functions through direct interaction with target genes. Modulation of the abundance of these receptors, such as changing their gene expression, alters the sensitivity of the target cells or tissues to the stimulation of ligands, and eventually affects the relevant physiological functions, such as growth, development, osteogenesis, immune response, lipogenesis, reproductive process, and anticarcinogenesis. A number of studies have shown that the bioactive components in soy can modify the expression of these receptors in various tissues and cancer cells, which is believed to be a key intracellular mechanism by which soy components affect physiological functions. This review summarizes the current understanding of the modulation of nuclear receptors by soy proteins and isoflavones, and focuses especially on the receptors for estrogens, progesterone, androgen, vitamin D, retinoic acid, and thyroid hormones as well as the potential impact on physiological functions.

  5. Post-depolarization potentiation of GABAA receptors: A novel mechanism regulating tonic conductance in hippocampal neurons

    PubMed Central

    Ransom, Christopher B.; Wu, Yuanming; Richerson, George B.

    2010-01-01

    Ambient GABA in the brain activates GABAA receptors to produce tonic inhibition. Membrane potential influences both GABA transport and GABAA receptors and could thereby regulate tonic inhibition. We investigated the voltage-dependence of tonic currents in cultured rat hippocampal neurons using patch clamp techniques. Tonic GABAA conductance increased with depolarization from 15±3 pS/pF at −80 mV to 29±5 pS/pF at −40 mV. Inhibition of vesicular or nonvesicular GABA release did not prevent voltage-dependent increases of tonic conductance. Currents evoked with exogenous GABA (1 µM) were outwardly-rectifying, similar to tonic currents due to endogenous GABA. These results indicate that the voltage-dependent increase of tonic conductance was due to intrinsic GABAA receptor properties rather than an elevation of ambient GABA. Following transient depolarization to +40 mV, endogenous tonic currents measured at −60 mV were increased by 75±17%. This novel form of tonic current modulation, termed post-depolarization potentiation (PDP), recovered with a time constant of 63 s, was increased by exogenous GABA, and inhibited by GABAA receptor antagonists. Measurements of EGABA showed PDP was due to increased conductance and not a change in the anion gradient. To assess the functional significance of PDP, we used voltage-clamp waveforms that replicated epileptiform activity. PDP was produced by this pathophysiologic depolarization. These data show that depolarization produces prolonged potentiation of tonic conductance due to voltage-dependent properties of GABAA receptors. These properties are well suited to limit excitability during pathophysiologic depolarization accompanied by rises in ambient GABA, such as occur during seizures and ischemia. PMID:20519542

  6. Cross-species sensitivity to a novel androgen receptor agonist of potential environmental concern, spironolactone.

    PubMed

    LaLone, Carlie A; Villeneuve, Daniel L; Cavallin, Jenna E; Kahl, Michael D; Durhan, Elizabeth J; Makynen, Elizabeth A; Jensen, Kathleen M; Stevens, Kyle E; Severson, Megan N; Blanksma, Chad A; Flynn, Kevin M; Hartig, Philip C; Woodard, Jonne S; Berninger, Jason P; Norberg-King, Teresa J; Johnson, Rodney D; Ankley, Gerald T

    2013-11-01

    Spironolactone is a pharmaceutical that in humans is used to treat conditions like hirsutism, various dermatologic afflictions, and female-pattern hair loss through antagonism of the androgen receptor. Although not routinely monitored in the environment, spironolactone has been detected downstream of a pharmaceutical manufacturer, indicating a potential for exposure of aquatic species. Furthermore, spironolactone has been reported to cause masculinization of female western mosquitofish, a response indicative of androgen receptor activation. Predictive methods to identify homologous proteins to the human and western mosquitofish androgen receptor suggest that vertebrates would be more susceptible to adverse effects mediated by chemicals like spironolactone that target the androgen receptor compared with invertebrate species that lack a relevant homolog. In addition, an adverse outcome pathway previously developed for activation of the androgen receptor suggests that androgen mimics can lead to reproductive toxicity in fish. To assess this, 21-d reproduction studies were conducted with 2 fish species, fathead minnow and Japanese medaka, and the invertebrate Daphnia magna. Spironolactone significantly reduced the fecundity of medaka and fathead minnows at 50 μg/L, whereas daphnia reproduction was not affected by concentrations as large as 500 μg/L. Phenotypic masculinization of females of both fish species was observed at 5 μg/L as evidenced by formation of tubercles in fathead minnows and papillary processes in Japanese medaka. Effects in fish occurred at concentrations below those reported in the environment. These results demonstrate how a priori knowledge of an adverse outcome pathway and the conservation of a key molecular target across vertebrates can be utilized to identify potential chemicals of concern in terms of monitoring and highlight potentially sensitive species and endpoints for testing.

  7. The D1 family dopamine receptor, DopR, potentiates hind leg grooming behavior in Drosophila

    PubMed Central

    Pitmon, E.; Stephens, G.; Parkhurst, S. J.; Wolf, F. W.; Kehne, G.; Taylor, M.

    2016-01-01

    Drosophila groom away debris and pathogens from the body using their legs in a stereotyped sequence of innate motor behaviors. Here, we investigated one aspect of the grooming repertoire by characterizing the D1 family dopamine receptor, DopR. Removal of DopR results in decreased hind leg grooming, as substantiated by quantitation of dye remaining on mutant and RNAi animals vs. controls and direct scoring of behavioral events. These data are also supported by pharmacological results that D1 receptor agonists fail to potentiate grooming behaviors in headless DopR flies. DopR protein is broadly expressed in the neuropil of the thoracic ganglion and overlaps with TH‐positive dopaminergic neurons. Broad neuronal expression of dopamine receptor in mutant animals restored normal grooming behaviors. These data provide evidence for the role of DopR in potentiating hind leg grooming behaviors in the thoracic ganglion of adult Drosophila. This is a remarkable juxtaposition to the considerable role of D1 family dopamine receptors in rodent grooming, and future investigations of evolutionary relationships of circuitry may be warranted. PMID:26749475

  8. Loss of inhibition by brain natriuretic peptide over P2X3 receptors contributes to enhanced spike firing of trigeminal ganglion neurons in a mouse model of familial hemiplegic migraine type-1.

    PubMed

    Marchenkova, Anna; van den Maagdenberg, Arn M J M; Nistri, Andrea

    2016-09-01

    Purinergic P2X3 receptors (P2X3Rs) play an important role in pain pathologies, including migraine. In trigeminal neurons, P2X3Rs are constitutively downregulated by endogenous brain natriuretic peptide (BNP). In a mouse knock-in (KI) model of familial hemiplegic migraine type-1 with upregulated calcium CaV2.1 channel function, trigeminal neurons exhibit hyperexcitability with gain-of-function of P2X3Rs and their deficient BNP-mediated inhibition. We studied whether the absent BNP-induced control over P2X3Rs activity in KI cultures may be functionally expressed in altered firing activity of KI trigeminal neurons. Patch-clamp experiments investigated the excitability of wild-type and KI trigeminal neurons induced by either current or agonists for P2X3Rs or transient receptor potential vanilloid-1 (TRPV1) receptors. Consistent with the constitutive inhibition of P2X3Rs by BNP, sustained pharmacological block of BNP receptors selectively enhanced P2X3R-mediated excitability of wild-type neurons without affecting firing evoked by the other protocols. This effect included increased number of action potentials, lower spike threshold and shift of the firing pattern distribution toward higher spiking activity. Thus, inactivation of BNP signaling transformed the wild-type excitability phenotype into the one typical for KI. BNP receptor block did not influence excitability of KI neurons in accordance with the lack of BNP-induced P2X3R modulation. Our study suggests that, in wild-type trigeminal neurons, negative control over P2X3Rs by the BNP pathway is translated into tonic suppression of P2X3Rs-mediated excitability. Lack of this inhibition in KI cultures results in a hyperexcitability phenotype and might contribute to facilitated trigeminal pain transduction relevant for migraine. PMID:27346147

  9. Regulation of Transient Receptor Potential channels by the phospholipase C pathway

    PubMed Central

    Rohacs, Tibor

    2013-01-01

    Transient Receptor Potential (TRP) channels were discovered while analyzing visual mutants in drosophila. The protein encoded by the transient receptor potential (trp) gene is a Ca2+ permeable cation channel activated downstream of the phospholipase C (PLC) pathway. While searching for homologues in other organisms, a surprisingly large number of mammalian TRP channels were cloned. The regulation of TRP channels is quite diverse, but many of them are either activated downstream of the PLC pathway, or modulated by it. This review will summarize the current knowledge on regulation of TRP channels by the PLC pathway, with special focus on TRPC-s, which can be considered as effectors of the PLC pathway, and the heat and capsaicin sensitive TRPV1, which is modulated by the PLC pathway in a complex manner. PMID:23916247

  10. Epidermal Growth Factor Receptor Transactivation: Mechanisms, Pathophysiology, and Potential Therapies in the Cardiovascular System.

    PubMed

    Forrester, Steven J; Kawai, Tatsuo; O'Brien, Shannon; Thomas, Walter; Harris, Raymond C; Eguchi, Satoru

    2016-01-01

    Epidermal growth factor receptor (EGFR) activation impacts the physiology and pathophysiology of the cardiovascular system, and inhibition of EGFR activity is emerging as a potential therapeutic strategy to treat diseases including hypertension, cardiac hypertrophy, renal fibrosis, and abdominal aortic aneurysm. The capacity of G protein-coupled receptor (GPCR) agonists, such as angiotensin II (AngII), to promote EGFR signaling is called transactivation and is well described, yet delineating the molecular processes and functional relevance of this crosstalk has been challenging. Moreover, these critical findings are dispersed among many different fields. The aim of our review is to highlight recent advancements in defining the signaling cascades and downstream consequences of EGFR transactivation in the cardiovascular renal system. We also focus on studies that link EGFR transactivation to animal models of the disease, and we discuss potential therapeutic applications.

  11. 3-Chloro,4-methoxyfendiline is a potent GABA(B) receptor potentiator in rat neocortical slices.

    PubMed

    Ong, Jennifer; Parker, David A S; Marino, Victor; Kerr, David I B; Puspawati, Ni Made; Prager, Rolf H

    2005-01-10

    Using grease-gap recording from rat neocortical slices, the GABA(B) receptor agonist baclofen elicited reversible and concentration-dependent hyperpolarizing responses (EC50=18+/-2.3 microM). The hyperpolarizations were antagonised by the GABA(B) receptor antagonist Sch 50911 [(+)-(S)-5,5-dimethylmorpholinyl-2-acetic acid). (+)-N-1-(3-chloro-4-methoxyphenyl)ethyl-3,3-diphenylpropylamine (3-chloro,4-methoxyfendiline; 3-Cl,4-MeO-fendiline) reversibly potentiated baclofen-induced hyperpolarizing responses, which were reduced by Sch 50911, producing leftward shifts of the baclofen concentration-response curves, with a marked increase in the maximal hyperpolarization (EC50=2+/-0.5 microM). In slices preincubated with either [3H]GABA or [3H]glutamic acid, 3-Cl,4-MeO-fendiline (1 microM) potentiated the inhibitory effect of baclofen (2 microM) on the electrically evoked release of [3H]GABA and had a similar effect on the release of [3H]glutamic acid at a concentration of 0.5 microM, without affecting the basal release. These effects were blocked by Sch 50911 (10 microM). Our findings suggest that 3-Cl,4-MeO-fendiline is a potent potentiator of pre- and postsynaptic GABA(B) receptor-mediated functions.

  12. QSAR classification of estrogen receptor binders and pre-screening of potential pleiotropic EDCs.

    PubMed

    Li, J; Gramatica, P

    2010-10-01

    Endocrine disrupting chemicals (EDCs) are suspected of posing serious threats to human and wildlife health through a variety of mechanisms, these being mainly receptor-mediated modes of action. It is reported that some EDCs exhibit dual activities as estrogen receptor (ER) and androgen receptor (AR) binders. Indeed, such compounds can affect the normal endocrine system through a dual complex mechanism, so steps should be taken not only to identify them a priori from their chemical structure, but also to prioritize them for experimental tests in order to reduce and even forbid their usage. To date, very few EDCs with dual activities have been identified. The present research uses QSARs, to investigate what, so far, is the largest and most heterogeneous ER binder data set (combined METI and EDKB databases). New predictive classification models were derived using different modelling methods and a consensus approach, and these were used to virtually screen a large AR binder data set after strict validation. As a result, 46 AR antagonists were predicted from their chemical structure to also have potential ER binding activities, i.e. pleiotropic EDCs. In addition, 48 not yet recognized ER binders were in silico identified, which increases the number of potential EDCs that are substances of very high concern (SVHC) in REACH. Thus, the proposed screening models, based only on structure information, have the main aim to prioritize experimental tests for the highlighted compounds with potential estrogenic activities and also to design safer alternatives.

  13. Multiscale design of coarse-grained elastic network-based potentials for the μ opioid receptor.

    PubMed

    Fossépré, Mathieu; Leherte, Laurence; Laaksonen, Aatto; Vercauteren, Daniel P

    2016-09-01

    Despite progress in computer modeling, most biological processes are still out of reach when using all-atom (AA) models. Coarse-grained (CG) models allow classical molecular dynamics (MD) simulations to be accelerated. Although simplification of spatial resolution at different levels is often investigated, simplification of the CG potential in itself has been less common. CG potentials are often similar to AA potentials. In this work, we consider the design and reliability of purely mechanical CG models of the μ opioid receptor (μOR), a G protein-coupled receptor (GPCR). In this sense, CG force fields (FF) consist of a set of holonomic constraints guided by an elastic network model (ENM). Even though ENMs are used widely to perform normal mode analysis (NMA), they are not often implemented as a single FF in the context of MD simulations. In this work, various ENM-like potentials were investigated by varying their force constant schemes and connectivity patterns. A method was established to systematically parameterize ENM-like potentials at different spatial resolutions by using AA data. To do so, new descriptors were introduced. The choice of conformation descriptors that also include flexibility information is important for a reliable parameterization of ENMs with different degrees of sensitivity. Hence, ENM-like potentials, with specific parameters, can be sufficient to accurately reproduce AA MD simulations of μOR at highly coarse-grained resolutions. Therefore, the essence of the flexibility properties of μOR can be captured with simple models at different CG spatial resolutions, opening the way to mechanical approaches to understanding GPCR functions. Graphical Abstract All atom structure, residue interaction network and coarse-grained elastic network models of the μ opioid receptor (μOR). PMID:27566318

  14. Multiscale design of coarse-grained elastic network-based potentials for the μ opioid receptor.

    PubMed

    Fossépré, Mathieu; Leherte, Laurence; Laaksonen, Aatto; Vercauteren, Daniel P

    2016-09-01

    Despite progress in computer modeling, most biological processes are still out of reach when using all-atom (AA) models. Coarse-grained (CG) models allow classical molecular dynamics (MD) simulations to be accelerated. Although simplification of spatial resolution at different levels is often investigated, simplification of the CG potential in itself has been less common. CG potentials are often similar to AA potentials. In this work, we consider the design and reliability of purely mechanical CG models of the μ opioid receptor (μOR), a G protein-coupled receptor (GPCR). In this sense, CG force fields (FF) consist of a set of holonomic constraints guided by an elastic network model (ENM). Even though ENMs are used widely to perform normal mode analysis (NMA), they are not often implemented as a single FF in the context of MD simulations. In this work, various ENM-like potentials were investigated by varying their force constant schemes and connectivity patterns. A method was established to systematically parameterize ENM-like potentials at different spatial resolutions by using AA data. To do so, new descriptors were introduced. The choice of conformation descriptors that also include flexibility information is important for a reliable parameterization of ENMs with different degrees of sensitivity. Hence, ENM-like potentials, with specific parameters, can be sufficient to accurately reproduce AA MD simulations of μOR at highly coarse-grained resolutions. Therefore, the essence of the flexibility properties of μOR can be captured with simple models at different CG spatial resolutions, opening the way to mechanical approaches to understanding GPCR functions. Graphical Abstract All atom structure, residue interaction network and coarse-grained elastic network models of the μ opioid receptor (μOR).

  15. Tumor necrosis factor and its receptors in human ovarian cancer. Potential role in disease progression.

    PubMed Central

    Naylor, M S; Stamp, G W; Foulkes, W D; Eccles, D; Balkwill, F R

    1993-01-01

    The gene for tumor necrosis factor, TNF, was expressed in 45 out of 63 biopsies of human epithelial ovarian cancer. In serous tumors, there was a positive correlation between level of TNF expression and tumor grade. TNF mRNA was found in epithelial tumor cells and infiltrating macrophages, whereas TNF protein localized primarily to a subpopulation of macrophages within and in close proximity to tumor areas. mRNA and protein for the p55 TNF receptor gene localized to the tumor epithelium and tumor, but not to stromal macrophages. The p75 TNF receptor was confined to infiltrating cells. Cells expressing TNF mRNA were also found in ovarian cancer ascites and TNF protein was detected in some ascitic fluids. In 2 out of 12 biopsies of normal ovary, TNF mRNA was detected in a minority of cells in the thecal layer of the corpus luteum. Serum levels of TNF and its soluble receptor did not correlate with extent of TNF expression in matched biopsies. Northern and Southern analysis revealed no gross abnormality of the TNF gene. The coexpression of TNF and its receptor in ovarian cancer biopsies suggests the capacity for autocrine/paracrine action. TNF antagonists may have therapeutic potential in this malignancy. Images PMID:8387543

  16. Nicotinic α7 receptor activation selectively potentiates the function of NMDA receptors in glutamatergic terminals of the nucleus accumbens.

    PubMed

    Zappettini, Stefania; Grilli, Massimo; Olivero, Guendalina; Chen, Jiayang; Padolecchia, Cristina; Pittaluga, Anna; Tomé, Angelo R; Cunha, Rodrigo A; Marchi, Mario

    2014-01-01

    We here provide functional and immunocytochemical evidence supporting the co-localization and functional interaction between nicotinic acetylcholine receptors (nAChRs) and N-methyl-D-aspartic acid receptors (NMDARs) in glutamatergic terminals of the nucleus accumbens (NAc). Immunocytochemical studies showed that a significant percentage of NAc terminals were glutamatergic and possessed GluN1 and α7-containing nAChR. A short-term pre-exposure of synaptosomes to nicotine (30 µM) or choline (1 mM) caused a significant potentiation of the 100 µM NMDA-evoked [(3)H]D-aspartate ([(3)H]D-Asp) outflow, which was prevented by α-bungarotoxin (100 nM). The pre-exposure to nicotine (100 µM) or choline (1 mM) also enhanced the NMDA-induced cytosolic free calcium levels, as measured by FURA-2 fluorescence imaging in individual NAc terminals, an effect also prevented by α-bungarotoxin. Pre-exposure to the α4-nAChR agonists 5IA85380 (10 nM) or RJR2429 (1 µM) did not modify NMDA-evoked ([(3)H]D-Asp) outflow and calcium transients. The NMDA-evoked ([(3)H]D-Asp) overflow was partially antagonized by the NMDAR antagonists MK801, D-AP5, 5,7-DCKA and R(-)CPP and unaffected by the GluN2B-NMDAR antagonists Ro256981 and ifenprodil. Notably, pre-treatment with choline increased GluN2A biotin-tagged proteins. In conclusion, our results show that the GluN2A-NMDA receptor function can be positively regulated in NAc terminals in response to a brief incubation with α7 but not α4 nAChRs agonists. This might be a general feature in different brain areas since a similar nAChR-mediated bolstering of NMDA-induced ([(3)H]D-Asp) overflow was also observed in hippocampal synaptosomes.

  17. Potential of GRID2 receptor gene for preventing TNF-induced neurodegeneration in autism.

    PubMed

    Kalkan, Zeynep; Durasi, İlknur Melis; Sezerman, Ugur; Atasever-Arslan, Belkis

    2016-05-01

    Autism is one of the most common subtypes of autism spectrum disorder (ASD). Recent studies suggested a relationship between immune-dependent coding genes and ASD, indicating that long term neuroimmunological anomalies affect brain development and synaptic transmission among neural networks. Furthermore, various studies focused on biomarker potential of TNF-α in autism. Ionotropic receptors are also studied as potential marker for autism since altered gene expression levels are observed in autistic patients. GRID2 is a candidate ionotropic receptor which is involved glutamate transfer. In this study, to propose TNF-α dependent cellular processes involved in autism aetiology in relation to GRID2 we performed a bioinformatic network analysis and identified potential pathways and genes that are involved in TNF-α induced changes at GRID2 receptor levels. As a result, we ascertained the GRID2 receptor gene as a candidate gene and further studied the association between GRID2 expression levels and TNF-induced neurodegeneration. Our bioinformatic analyses and experimental results revealed that TNF-α regulates GRID2 gene expression by activating Cdc42 and GOPC genes. Moreover, increased TNF-α levels leads to increase of caspase-3 protein levels triggering neuronal apoptosis leading to neuronal deficiency, which is one of the major symptoms of autism. The study is the first to show the role of TNF-α in regulation of GRID2 gene expression and its signalling pathway. As a result, GRID2 gene can be a suppressor in TNF-induced neurodegeneration which may help to understand the main factors leading to autism.

  18. Capsaicin may have important potential for promoting vascular and metabolic health

    PubMed Central

    McCarty, Mark F; DiNicolantonio, James J; O'Keefe, James H

    2015-01-01

    Capsaicin, the phytochemical responsible for the spiciness of peppers, has the potential to modulate metabolism via activation of transient receptor potential vanilloid 1 (TRPV1) receptors, which are found not only on nociceptive sensory neurons, but also in a range of other tissues. TRPV1 activation induces calcium influx, and in certain tissues this is associated with increased activation or expression of key proteins such as endothelial nitric oxide synthase (eNOS), uncoupling protein 2 (UCP2), KLF2, PPARdelta, PPARgamma, and LXRα. The calcium influx triggered by TRPV1 activation in endothelial cells mimics the impact of shear stress in this regard, activating and increasing the expression of eNOS—but also increasing expression of cox-2, thrombomodulin, and nrf2-responsive antioxidant enzymes, while decreasing expression of proinflammatory proteins. Hence, dietary capsaicin has favourably impacted endothelium-dependent vasodilation in rodents. TRPV1-mediated induction of LXRα in foam cells promotes cholesterol export, antagonising plaque formation. Capsaicin-mediated activation of TRPV1-expressing neurons in the gastrointestinal tract promotes sympathetically mediated stimulation of brown fat, raising metabolic rate. The increased expression of UCP2 induced by TRPV1 activation exerts a protective antioxidant effect on the liver in non-alcoholic fatty liver disease, and on vascular endothelium in the context of hyperglycaemia. In rodent studies, capsaicin-rich diets have shown favourable effects on atherosclerosis, metabolic syndrome, diabetes, obesity, non-alcoholic fatty liver, cardiac hypertrophy, hypertension and stroke risk. Clinically, ingestion of capsaicin—or its less stable non-pungent analogue capsiate—has been shown to boost metabolic rate modestly. Topical application of capsaicin via patch was found to increase exercise time to ischaemic threshold in patients with angina. Further clinical studies with capsaicin administered in food, capsules

  19. A descriptive model of the receptor potential nonlinearities generated by the hair cell mechanoelectrical transducer.

    PubMed

    Lukashkin, A N; Russell, I J

    1998-02-01

    This paper describes a model for generating the hair cell receptor potential based on a second-order Boltzmann function. The model includes only the resistive elements of the hair cell membranes with batteries across them and the series resistance of the external return path of the transducer current through the tissue of the cochlea. The model provides a qualitative description of signal processing by the hair cell transducer and shows that the nonlinearity of the hair cell transducer can give rise to nonlinear phenomena, such as intermodulation distortion products and two-tone suppression with patterns similar to those which have been recorded from the peripheral auditory system. Particular outcomes of the model are the demonstration that two-tone suppression depends not on the saturation of the receptor current, but on the behaviour of the hair cell transducer function close to the operating point. The model also shows that there is non-monotonic growth and phase change for any spectral component, but not for the fundamental of the receptor potential. PMID:9479750

  20. [Discovery of potential nicotinic acid receptor agonists from Chinese herbal medicines based on molecular simulation].

    PubMed

    Jiang, Lu-Di; He, Yu-Su; Zhang, Yan-Ling

    2014-12-01

    Nicotinic acid could increase high density lipoprotein and reduce serum total cholesterol, low density lipoprotein cholesterol and triglycerides in human bodies, thus is frequently applied in treating low high-density lipoprotein cholesterol and hypertriglyceridemia in clinic. However, according to the findings, nicotinic acid could also cause adverse effects, such as skin flush, beside its curative effects. In this study, bioisosterism, fragment-based search and Lipinski's Rule of Five were used to preliminarily screen out potential TCM ingredients that may have similar pharmacological effects with nicotinic acid from Traditional Chinese medicine database (TCMD). Afterwards, homology modeling and flexible docking were used to further screen out potential nicotinic acid receptor agonists. As a result, eleven candidate compounds were derived from eight commonly used traditional Chinese medicines. Specifically, all of the candidate compounds' interaction with nicotinic acid receptor was similar to nicotinic acid, and their docking scores were all higher than that of nicotinic acid, but their druggability remained to be further studied. Some of the eight source traditional Chinese medicines were used to lower lipid according to literature studies, implying that they may show effect through above means. In summary, this study provides basis and reference for extracting new nicotinic acid receptor agonists from traditional Chinese medicines and improving the medication status of hyperlipidemia.

  1. Polymodal Transient Receptor Potential Vanilloid Type 1 Nocisensor: Structure, Modulators, and Therapeutic Applications.

    PubMed

    Cui, Minghua; Gosu, Vijayakumar; Basith, Shaherin; Hong, Sunhye; Choi, Sun

    2016-01-01

    Transient receptor potential (TRP) channels belong to a superfamily of sensory-related ion channels responding to a wide variety of thermal, mechanical, or chemical stimuli. In an attempt to comprehend the piquancy and pain mechanism of the archetypal vanilloids, transient receptor potential vanilloid (TRPV) 1 was discovered. TRPV1, a well-established member of the TRP family, is implicated in a range of functions including inflammation, painful stimuli sensation, and mechanotransduction. TRPV1 channels are nonselective cation receptors that are gated by a broad array of noxious ligands. Such polymodal-sensor aspect makes the TRPV1 channel extremely versatile and important for its role in sensing burning pain. Besides ligands, TRPV1 signaling can also be modulated by lipids, secondary messengers, protein kinases, cytoskeleton, and several other proteins. Due to its central role in hyperalgesia transduction and inflammatory processes, it is considered as the primary pharmacological pain target. Moreover, understanding the structural and functional intricacies of the channel is indispensable for the therapeutic intervention of TRPV1 in pain and other pathological disorders. In this chapter, we seek to give a mechanistic outlook on the TRPV1 channel. Specifically, we will explore the TRPV1 structure, activation, modulation, ligands, and its therapeutic targeting. However, the major objective of this review is to highlight the fact that TRPV1 channel can be treated as an effective therapeutic target for treating several pain- and nonpain-related physiological and pathological states. PMID:27038373

  2. Serotonin stimulates lateral habenula via activation of the post-synaptic serotonin 2/3 receptors and transient receptor potential channels.

    PubMed

    Zuo, Wanhong; Zhang, Yong; Xie, Guiqin; Gregor, Danielle; Bekker, Alex; Ye, Jiang-Hong

    2016-02-01

    There is growing interest on the role of the lateral habenula (LHb) in depression, because it closely and bilaterally connects with the serotoninergic raphe nuclei. The LHb sends glutamate efferents to the raphe nuclei, while it receives serotoninergic afferents, and expresses a high density of serotonin (5-HT) receptors. Recent studies suggest that 5-HT receptors exist both in the presynaptic and postsynaptic sites of LHb neurons, and activation of these receptors may have different effects on the activity of LHb neurons. The current study focused on the effect of 5-HT on the postsynaptic membrane. We found that 5-HT initiated a depolarizing inward current (I((5-HTi))) and accelerated spontaneous firing in ∼80% of LHb neurons in rat brain slices. I((5-HTi)) was also induced by the 5-HT uptake blocker citalopram, indicating activity of endogenous 5-HT. I((5-HTi)) was diminished by 5-HT(2/3) receptor antagonists (ritanserin, SB-200646 or ondansetron), and activated by the selective 5-HT(2/3) agonists 1-(3-Chlorophenyl) piperazine hydrochloride or 1-(3-Chlorophenyl) biguanide hydrochloride. Furthermore, I((5-HTi)) was attenuated by 2-Aminoethyl diphenylborinate, a blocker of transient receptor potential channels, and an IP3 receptor inhibitor, indicating the involvement of transient receptor potential channels. These results demonstrate that the reciprocal connection between the LHb and the 5-HT system highlights a key role for 5-HT stimulation of LHb neurons that may be important in the pathogenesis of depression.

  3. Therapeutic Potential of 5-HT2C Receptor Agonists for Addictive Disorders.

    PubMed

    Higgins, Guy A; Fletcher, Paul J

    2015-07-15

    The neurotransmitter 5-hydroxytryptamine (5-HT; serotonin) has long been associated with the control of a variety of motivated behaviors, including feeding. Much of the evidence linking 5-HT and feeding behavior was obtained from studies of the effects of the 5-HT releaser (dex)fenfluramine in laboratory animals and humans. Recently, the selective 5-HT2C receptor agonist lorcaserin received FDA approval for the treatment of obesity. This review examines evidence to support the use of selective 5-HT2C receptor agonists as treatments for conditions beyond obesity, including substance abuse (particularly nicotine, psychostimulant, and alcohol dependence), obsessive compulsive, and excessive gambling disorder. Following a brief survey of the early literature supporting a role for 5-HT in modulating food and drug reinforcement, we propose that intrinsic differences between SSRI and serotonin releasers may have underestimated the value of serotonin-based pharmacotherapeutics to treat clinical forms of addictive behavior beyond obesity. We then highlight the critical involvement of the 5-HT2C receptor in mediating the effect of (dex)fenfluramine on feeding and body weight gain and the evidence that 5-HT2C receptor agonists reduce measures of drug reward and impulsivity. A recent report of lorcaserin efficacy in a smoking cessation trial further strengthens the idea that 5-HT2C receptor agonists may have potential as a treatment for addiction. This review was prepared as a contribution to the proceedings of the 11th International Society for Serotonin Research Meeting held in Hermanus, South Africa, July 9-12, 2014.

  4. Modulation of defensive behavior by Transient Receptor Potential Vanilloid Type-1 (TRPV1) channels.

    PubMed

    Aguiar, D C; Moreira, F A; Terzian, A L; Fogaça, M V; Lisboa, S F; Wotjak, C T; Guimaraes, F S

    2014-10-01

    The Transient Receptor Potential Vanilloid Type-1 (TRPV1) was first characterized in primary afferent fibers as a receptor for capsaicin (the pungent ingredient of chili peppers). Later on, this cation-permeable ion channel was also described in the central nervous system, where its main putative endogenous ligand is N-arachidonoyl ethanolamide (an endocannabinoid, also known as anandamide). Recent results employing genetic, pharmacological and histochemical techniques indicate that TRPV1 tonically modulate anxiety, fear and panic responses in brain regions related to defensive responses, such as the dorsal periaqueductal gray, the hippocampus and the medial prefrontal cortex. Genetic deletion or antagonism of this ion channel induces anxiolytic-like effects in several animal models. The main mechanism responsible for TRPV1-mediated effects on anxiety seems to involve facilitation of glutamatergic neurotransmission. In addition, there is evidence for interactions with other neurotransmitter systems, such as nitric oxide and endocannabinoids. PMID:24726577

  5. Modulation of defensive behavior by Transient Receptor Potential Vanilloid Type-1 (TRPV1) channels.

    PubMed

    Aguiar, D C; Moreira, F A; Terzian, A L; Fogaça, M V; Lisboa, S F; Wotjak, C T; Guimaraes, F S

    2014-10-01

    The Transient Receptor Potential Vanilloid Type-1 (TRPV1) was first characterized in primary afferent fibers as a receptor for capsaicin (the pungent ingredient of chili peppers). Later on, this cation-permeable ion channel was also described in the central nervous system, where its main putative endogenous ligand is N-arachidonoyl ethanolamide (an endocannabinoid, also known as anandamide). Recent results employing genetic, pharmacological and histochemical techniques indicate that TRPV1 tonically modulate anxiety, fear and panic responses in brain regions related to defensive responses, such as the dorsal periaqueductal gray, the hippocampus and the medial prefrontal cortex. Genetic deletion or antagonism of this ion channel induces anxiolytic-like effects in several animal models. The main mechanism responsible for TRPV1-mediated effects on anxiety seems to involve facilitation of glutamatergic neurotransmission. In addition, there is evidence for interactions with other neurotransmitter systems, such as nitric oxide and endocannabinoids.

  6. Activation of Muscarinic M1 Acetylcholine Receptors Induces Long-Term Potentiation in the Hippocampus.

    PubMed

    Dennis, Siobhan H; Pasqui, Francesca; Colvin, Ellen M; Sanger, Helen; Mogg, Adrian J; Felder, Christian C; Broad, Lisa M; Fitzjohn, Steve M; Isaac, John T R; Mellor, Jack R

    2016-01-01

    Muscarinic M1 acetylcholine receptors (M1Rs) are highly expressed in the hippocampus, and their inhibition or ablation disrupts the encoding of spatial memory. It has been hypothesized that the principal mechanism by which M1Rs influence spatial memory is by the regulation of hippocampal synaptic plasticity. Here, we use a combination of recently developed, well characterized, selective M1R agonists and M1R knock-out mice to define the roles of M1Rs in the regulation of hippocampal neuronal and synaptic function. We confirm that M1R activation increases input resistance and depolarizes hippocampal CA1 pyramidal neurons and show that this profoundly increases excitatory postsynaptic potential-spike coupling. Consistent with a critical role for M1Rs in synaptic plasticity, we now show that M1R activation produces a robust potentiation of glutamatergic synaptic transmission onto CA1 pyramidal neurons that has all the hallmarks of long-term potentiation (LTP): The potentiation requires NMDA receptor activity and bi-directionally occludes with synaptically induced LTP. Thus, we describe synergistic mechanisms by which acetylcholine acting through M1Rs excites CA1 pyramidal neurons and induces LTP, to profoundly increase activation of CA1 pyramidal neurons. These features are predicted to make a major contribution to the pro-cognitive effects of cholinergic transmission in rodents and humans. PMID:26472558

  7. Novel gold nanoparticles coated with somatostatin as a potential delivery system for targeting somatostatin receptors.

    PubMed

    Abdellatif, Ahmed A H; Zayed, Gamal; El-Bakry, Asmaa; Zaky, Alaa; Saleem, Imran Y; Tawfeek, Hesham M

    2016-11-01

    Targeting of G-protein coupled receptors (GPCRs) like somatostatin-14 (SST-14) could have a potential interest in delivery of anti-cancer agents to tumor cells. Attachment of SST to different nano-carriers e.g. polymeric nanoparticles is limited due to the difficulty of interaction between SST itself and those nano-carriers. Furthermore, the instability problems associated with the final formulation. Attaching of SST to gold nanoparticles (AuNPs) using the positive and negative charge of SST and citrate-AuNPs could be considered a new technique to get stable non-aggregated AuNPs coated with SST. Different analyses techniques have been performed to proof the principle of coating between AuNPs and SST. Furthermore, cellular uptake studies on HCC-1806, HELA and U-87 cell lines has been investigated to show the ability of AuNPs coated SST to enter the cells via SST receptors. Dynamic light scattering (DLS) indicated a successful coating of SST on the MUA-AuNPs surface. Furthermore, all the performed analysis including DLS, SDS-PAGE and UV-VIS absorption spectra indicated a successful coating of AuNPs with SST. Cellular uptake studies on HCC-1806, HELA and U-87 cell lines showed that the number of AuNPs-SST per cell is signiflcantly higher compared to citrate-AuNPs when quantified using inductively coupled plasma spectroscopy. Moreover, the binding of AuNPs-SST to cells can be suppressed by addition of antagonist, indicating that the binding of AuNPs-SST to cells is due to receptor-specific binding. In conclusion, AuNPs could be attached to SST via adsorption to get stable AuNPs coated SST. This new formulation has a potential to target SST receptors localized in many normal and tumor cells. PMID:27032509

  8. A common molecular basis for exogenous and endogenous cannabinoid potentiation of glycine receptors.

    PubMed

    Xiong, Wei; Wu, Xiongwu; Li, Fuying; Cheng, Kejun; Rice, Kenner C; Lovinger, David M; Zhang, Li

    2012-04-11

    Both exogenous and endogenous cannabinoids can allosterically modulate glycine receptors (GlyRs). However, little is known about the molecular basis of cannabinoid-GlyR interactions. Here we report that sustained incubation with the endocannabinoid anandamide (AEA) substantially increased the amplitude of glycine-activated current in both rat cultured spinal neurons and in HEK-293 cells expressing human α1, rat α2 and α3 GlyRs. While the α1 and α3 subunits were highly sensitive to AEA-induced potentiation, the α2 subunit was relatively insensitive to AEA. Switching a serine at 296 and 307 in the TM3 (transmembrane domain 3) of the α1 and α3 subunits with an alanine (A) at the equivalent position in the α2 subunit converted the α1/α3 AEA-sensitive receptors to sensitivity resembling that of α2. The S296 residue is also critical for exogenous cannabinoid-induced potentiation of I(Gly). The magnitude of AEA potentiation decreased with removal of either the hydroxyl or oxygen groups on AEA. While desoxy-AEA was significantly less efficacious in potentiating I(Gly), desoxy-AEA inhibited potentiation produced by both Δ(9)-tetrahydrocannabinol (THC), a major psychoactive component of marijuana, and AEA. Similarly, didesoxy-THC, a modified THC with removal of both hydroxyl/oxygen groups, did not affect I(Gly) when applied alone but inhibited the potentiation of I(Gly) induced by AEA and THC. These findings suggest that exogenous and endogenous cannabinoids potentiate GlyRs via a hydrogen bonding-like interaction. Such a specific interaction likely stems from a common molecular basis involving the S296 residue in the TM3 of the α1 and α3 subunits. PMID:22496565

  9. Characterization of a Ligand Binding Site in the Human Transient Receptor Potential Ankyrin 1 Pore

    PubMed Central

    Klement, Göran; Eisele, Lina; Malinowsky, David; Nolting, Andreas; Svensson, Mats; Terp, Gitte; Weigelt, Dirk; Dabrowski, Michael

    2013-01-01

    The pharmacology and regulation of Transient Receptor Potential Ankyrin 1 (TRPA1) ion channel activity is intricate due to the physiological function as an integrator of multiple chemical, mechanical, and temperature stimuli as well as differences in species pharmacology. In this study, we describe and compare the current inhibition efficacy of human TRPA1 on three different TRPA1 antagonists. We used a homology model of TRPA1 based on Kv1.2 to select pore vestibule residues available for interaction with ligands entering the vestibule. Site-directed mutation constructs were expressed in Xenopus oocytes and their functionality and pharmacology assessed to support and improve our homology model. Based on the functional pharmacology results we propose an antagonist-binding site in the vestibule of the TRPA1 ion channel. We use the results to describe the proposed intravestibular ligand-binding site in TRPA1 in detail. Based on the single site substitutions, we designed a human TRPA1 receptor by substituting several residues in the vestibule and adjacent regions from the rat receptor to address and explain observed species pharmacology differences. In parallel, the lack of effect on HC-030031 inhibition by the vestibule substitutions suggests that this molecule interacts with TRPA1 via a binding site not situated in the vestibule. PMID:23442958

  10. Characterization of a ligand binding site in the human transient receptor potential ankyrin 1 pore.

    PubMed

    Klement, Göran; Eisele, Lina; Malinowsky, David; Nolting, Andreas; Svensson, Mats; Terp, Gitte; Weigelt, Dirk; Dabrowski, Michael

    2013-02-19

    The pharmacology and regulation of Transient Receptor Potential Ankyrin 1 (TRPA1) ion channel activity is intricate due to the physiological function as an integrator of multiple chemical, mechanical, and temperature stimuli as well as differences in species pharmacology. In this study, we describe and compare the current inhibition efficacy of human TRPA1 on three different TRPA1 antagonists. We used a homology model of TRPA1 based on Kv1.2 to select pore vestibule residues available for interaction with ligands entering the vestibule. Site-directed mutation constructs were expressed in Xenopus oocytes and their functionality and pharmacology assessed to support and improve our homology model. Based on the functional pharmacology results we propose an antagonist-binding site in the vestibule of the TRPA1 ion channel. We use the results to describe the proposed intravestibular ligand-binding site in TRPA1 in detail. Based on the single site substitutions, we designed a human TRPA1 receptor by substituting several residues in the vestibule and adjacent regions from the rat receptor to address and explain observed species pharmacology differences. In parallel, the lack of effect on HC-030031 inhibition by the vestibule substitutions suggests that this molecule interacts with TRPA1 via a binding site not situated in the vestibule.

  11. Arsenite and insulin exhibit opposing effects on epidermal growth factor receptor and keratinocyte proliferative potential

    SciTech Connect

    Patterson, Timothy J.; Rice, Robert H. . E-mail: rhrice@ucdavis.edu

    2007-05-15

    Previous work has suggested that arsenic exposure contributes to skin carcinogenesis by preserving the proliferative potential of human epidermal keratinocytes, thereby slowing the exit of putative target stem cells into the differentiation pathway. To find a molecular basis for this action, present work has explored the influence of arsenite on keratinocyte responses to epidermal growth factor (EGF). The ability of cultured keratinocytes to found colonies upon passaging several days after confluence was preserved by arsenite and EGF in an additive fashion, but neither was effective when the receptor tyrosine kinase activity was inhibited. Arsenite prevented the loss of EGF receptor protein and phosphorylation of tyrosine 1173, preserving its capability to signal. The level of nuclear {beta}-catenin was higher in cells treated with arsenite and EGF in parallel to elevated colony forming ability, and expression of a dominant negative {beta}-catenin suppressed the increase in both colony forming ability and yield of putative stem cells induced by arsenite and EGF. As judged by expression of three genes regulated by {beta}-catenin, this transcription factor had substantially higher activity in the arsenite/EGF-treated cells. Trivalent antimony exhibited the same effects as arsenite. A novel finding is that insulin in the medium induced the loss of EGF receptor protein, which was largely prevented by arsenite exposure.

  12. Structure, Dynamics, and Allosteric Potential of Ionotropic Glutamate Receptor N-Terminal Domains

    PubMed Central

    Krieger, James; Bahar, Ivet; Greger, Ingo H.

    2015-01-01

    Ionotropic glutamate receptors (iGluRs) are tetrameric cation channels that mediate synaptic transmission and plasticity. They have a unique modular architecture with four domains: the intracellular C-terminal domain (CTD) that is involved in synaptic targeting, the transmembrane domain (TMD) that forms the ion channel, the membrane-proximal ligand-binding domain (LBD) that binds agonists such as L-glutamate, and the distal N-terminal domain (NTD), whose function is the least clear. The extracellular portion, comprised of the LBD and NTD, is loosely arranged, mediating complex allosteric regulation and providing a rich target for drug development. Here, we briefly review recent work on iGluR NTD structure and dynamics, and further explore the allosteric potential for the NTD in AMPA-type iGluRs using coarse-grained simulations. We also investigate mechanisms underlying the established NTD allostery in NMDA-type iGluRs, as well as the fold-related metabotropic glutamate and GABAB receptors. We show that the clamshell motions intrinsically favored by the NTD bilobate fold are coupled to dimeric and higher-order rearrangements that impact the iGluR LBD and ultimately the TMD. Finally, we explore the dynamics of intact iGluRs and describe how it might affect receptor operation in a synaptic environment. PMID:26255587

  13. Vandetanib as a potential new treatment for estrogen receptor-negative breast cancers.

    PubMed

    Hatem, Rana; Labiod, Dalila; Château-Joubert, Sophie; de Plater, Ludmilla; El Botty, Rania; Vacher, Sophie; Bonin, Florian; Servely, Jean-Luc; Dieras, Véronique; Bièche, Ivan; Marangoni, Elisabetta

    2016-05-15

    The receptor tyrosine kinase RET is implicated in the progression of luminal breast cancers (BC) but its role in estrogen receptor (ER) negative tumors is unknown. Here we investigated the expression of RET in breast cancer patients tumors and patient-derived xenografts (PDX) and evaluated the therapeutic potential of Vandetanib, a tyrosin kinase inhibitor with strong activity against RET, EGFR and VEGFR2, in ER negative breast cancer PDX. The RT-PCR analysis of RET expression in breast tumors of 446 patients and 57 PDX, showed elevated levels of RET in ER+ and HER2+ subtypes and in a small subgroup of triple-negative breast cancers (TNBC). The activity of Vandetanib was tested in vivo in three PDX models of TNBC and one model of HER2+ BC with different expression levels of RET and EGFR. Vandetanib induced tumor regression in PDX models with high expression of RET or EGFR. The effect was associated with inhibition of RET/EGFR phosphorylation and MAP kinase pathway and increased necrosis. In a PDX model with no expression of RET nor EGFR, Vandetanib slowed tumor growth without inducing tumor regression. In addition, treatment by Vandetanib decreased expression of murine Vegf receptors and the endothelial marker Cd31 in the four PDX models tested, suggesting inhibition of tumor vascularization. In summary, these preclinical results suggest that Vandetanib treatment could be useful for patients with ER negative breast cancers overexpressing Vandetanib's main targets.

  14. Progress in developing cholecystokinin (CCK)/gastrin receptor ligands which have therapeutic potential

    PubMed Central

    Berna, Marc J.; Tapia, Jose A.; Sancho, Veronica; Jensen, Robert T.

    2007-01-01

    Summary Gastrin and CCK are two of the oldest hormones and within the last 15 years there has been an exponential increase in knowledge of their pharmacology, cell biology, receptors (CCK1R, CCK2R) and roles in physiology and pathological conditions. Despite these advances there is no approved disease indication for CCK receptor antagonists and only minor use of agonists. In this review the important factors determining this slow therapeutic development are reviewed. To assess this it is necessary to briefly review what is known about the roles of CCK receptors (CCK1R, CCK2R) in normal human physiology, their role in pathologic conditions, the selectivity of available potent CCKR agonists/antagonists as well as review their use in human conditions to date and the results. Despite extensive studies in animals and some in humans, recent studies suggest that monotherapy with CCK1R agonists will not be effective in obesity, nor CCK2R antagonists in panic disorders or CCK2R antagonists to inhibit growth of pancreatic cancer. Areas that require more study include the use of CCK2R agonists for imaging tumors and radiotherapy, CCK2R antagonists in hypergastrinemic states especially with long term PPI use and for potentiation of analgesia as well as use of CCK1R antagonists for a number of gastrointestinal disorders [motility disorders (irritable bowel syndrome, dyspepsia, constipation) and pancreatitis (acute, chronic)]. PMID:17997137

  15. An analysis of receptor potential and tension of isolated cat muscle spindles in response to sinusoidal stretch.

    PubMed Central

    Hunt, C C; Wilkinson, R S

    1980-01-01

    In isolated cat muscle spindles the receptor potential responses of primary and secondary endings as well as tension responses to sinusoidal length changes in the steady state have been analysed. 1. At a given stimulus frequency, receptor potential per unit length change (receptor potential gain) in both primary and secondary endings is constant when displacement is less than about 10 micrometer. With larger stretches, receptor potential gain decreases approximately as a power function of displacement, the gain of primary endings decreasing more rapidly with increasing displacement than that of secondary endings. Tension per unit length change (tension gain) shows a similar constant range above which it also decreases as a power function of displacement. 2. In spite of the large reduction in gain at high displacement amplitudes, response wave forms remained essentially sinusoidal. The gain reduction results principally from a displacement-dependent non-linearity which has a rapid onset and slow decay. 3. Receptor potential and tension responses to small amplitude sinusoidal stretch depend, in a parallel manner, on the initial length of the preparation. 4. Both receptor potential and tension responses are highly dependent on frequency of sinusoidal stretch. In primary endings receptor potential gain increased as a power function of frequency over the range 0 . 01 to about 40 Hz, above which frequency the gain decreased; phase advance remained relatively constant up to 10 Hz then decreased to become a phase lag at higher frequency. In secondary endings receptor potential gain remained fairly constant between 0 . 01 and 1 Hz then rose as a power function of frequency but less steeply than in primary endings. 3. The possible mechanisms underlying these findings are discussed. PMID:6447781

  16. Type-3 metabotropic glutamate receptors negatively modulate bone morphogenetic protein receptor signaling and support the tumourigenic potential of glioma-initiating cells.

    PubMed

    Ciceroni, C; Arcella, A; Mosillo, P; Battaglia, G; Mastrantoni, E; Oliva, M A; Carpinelli, G; Santoro, F; Sale, P; Ricci-Vitiani, L; De Maria, R; Pallini, R; Giangaspero, F; Nicoletti, F; Melchiorri, D

    2008-09-01

    Targeted-therapies enhancing differentiation of glioma-initiating cells (GICs) are potential innovative approaches to the treatment of malignant gliomas. These cells support tumour growth and recurrence and are resistant to radiotherapy and chemotherapy. We have found that GICs express mGlu3 metabotropic glutamate receptors. Activation of these receptors sustained the undifferentiated state of GICs in culture by negatively modulating the action of bone morphogenetic proteins, which physiologically signal through the phosphorylation of the transcription factors, Smads. The cross-talk between mGlu3 receptors and BMP receptors was mediated by the activation of the mitogen-activated protein kinase pathway. Remarkably, pharmacological blockade of mGlu3 receptors stimulated the differentiation of cultured GICs into astrocytes, an effect that appeared to be long lasting, independent of the growth conditions, and irreversible. In in vivo experiments, a 3-month treatment with the brain-permeant mGlu receptor antagonist, LY341495 limited the growth of infiltrating brain tumours originating from GICs implanted into the brain parenchyma of nude mice. While clusters of tumour cells were consistently found in the brain of control mice, they were virtually absent in a large proportion of mice treated with LY341495. These findings pave the way to a new non-cytotoxic treatment of malignant gliomas based on the use of mGlu3 receptor antagonists. PMID:18621067

  17. Bilaterally evoked monosynaptic EPSPs, NMDA receptors and potentiation in rat sympathetic preganglionic neurones in vitro.

    PubMed

    Spanswick, D; Renaud, L P; Logan, S D

    1998-05-15

    1. Whole-cell patch clamp and intracellular recordings were obtained from 190 sympathetic preganglionic neurones (SPNs) in spinal cord slices of neonatal rats. Fifty-two of these SPNs were identified histologically as innervating the superior cervical ganglion (SCG) by the presence of Lucifer Yellow introduced from the patch pipette and the appearance of retrograde labelling following the injection of rhodamine-dextran-lysine into the SCG. 2. Electrical stimulation of the ipsilateral (n = 71) or contralateral (n = 32) lateral funiculi (iLF and cLF, respectively), contralateral intermediolateral nucleus (cIML, n = 41) or ipsilateral dorsal horn (DH, n = 34) evoked EPSPs or EPSCs that showed a constant latency and rise time, graded response to increased stimulus intensity, and no failures, suggesting a monosynaptic origin. 3. In all neurones tested (n = 60), fast rising and decaying components of EPSPs or EPSCs evoked from the iLF, cLF, cIML and DH in response to low-frequency stimulation (0.03-0.1 Hz) were sensitive to non-NMDA receptor antagonists. 4. In approximately 50 % of neurones tested (n = 29 of 60), EPSPs and EPSCs evoked from the iLF, cLF, cIML and DH during low-frequency stimulation were reduced by NMDA receptor antagonists. In the remaining neurones, an NMDA receptor antagonist-sensitive EPSP or EPSC was revealed only in magnesium-free bathing medium, or following high-frequency stimulation. 5. EPSPs evoked by stimulation of the iLF exhibited a sustained potentiation of the peak amplitude (25.3 +/- 11.4 %) in six of fourteen SPNs tested following a brief high-frequency stimulus (10-20 Hz, 0.1-2 s). 6. These results indicate that SPNs, including SPNs innervating the SCG, receive monosynaptic connections from both sides of the spinal cord. The neurotransmitter mediating transmission in some of the pathways activated by stimulation of iLF, cLF, cIML and DH is glutamate acting via both NMDA and non-NMDA receptors. Synaptic plasticity is a feature of

  18. Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials

    NASA Technical Reports Server (NTRS)

    Jones, S. M.; Jones, T. A.; Bell, P. L.; Taylor, M. J.

    2001-01-01

    The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

  19. Molecular dynamics study-based mechanism of nefiracetam-induced NMDA receptor potentiation.

    PubMed

    Omotuyi, Olaposi I; Ueda, Hiroshi

    2015-04-01

    Plastic changes in the brain required for memory formation and long-term learning are dependent on N-methyl-d-aspartic acid (NMDA) receptor signaling. Nefiracetam reportedly boosts NMDA receptor functions as a basis for its nootropic properties. Previous studies suggest that nefiracetam potentiates the NMDA receptor activation, as a more potent co-agonist for glycine binding site than glycine, though the underlying mechanisms remain elusive. Here, using BSP-SLIM method, a novel binding site within the core of spiral β-strands-1-5 of LBD-GLUN1 has been predicted in glycine-bound GLUN1 conformation in addition to the glycine pocket in Apo-GLUN1. Within the core of spiral β-strands-1-5 of LBD-GLUN1 pocket, all-atom molecular dynamics simulation revealed that nefiracetam disrupts Arg523-glycine-Asp732 interaction resulting in open GLUN1 conformation and ultimate diffusion of glycine out of the clamshell cleft. Open GLUN1 conformation coerces other intra-chain domains and proximal inter-chain domains to sample inactivate conformations resulting in closure of the transmembrane gate via a novel gauche trap on threonine 647 (chi-1 dihedral (χ1)=-45° instead of +45°). Docking of nefiracetam into the glycine pocket reversed the gauche trap and meditates partial opening of the TMD gate within a time-scale of 100ns as observed in glycine-only state. All these results suggest that nefiracetam can favorably complete with glycine for GLUN1-LBD in a two-step process, first by binding to a novel site of GLUN1-LBD-NMDA receptor followed by disruption of glycine-binding dynamics then replacing glycine in the GLUN1-LBD cleft. PMID:25659913

  20. The proteasome inhibitor Bortezomib (Velcade) as potential inhibitor of estrogen receptor-positive breast cancer.

    PubMed

    Thaler, Sonja; Thiede, Gitta; Hengstler, Jan G; Schad, Arno; Schmidt, Marcus; Sleeman, Jonathan P

    2015-08-01

    Around 70% of breast cancers express the estrogen receptor α (ERα) and depend on estrogen for growth, survival and disease progression. The presence of hormone sensitivity is usually associated with a favorable prognosis. Use of adjuvant anti-endocrine therapy has significantly decreased breast cancer mortality in patients with early-stage disease, and anti-endocrine therapy also plays a central role in the treatment of advanced stages. However a subset of hormone receptor-positive breast cancers do not benefit from anti-endocrine therapy, and nearly all hormone receptor-positive metastatic breast cancers ultimately develop resistance to anti-hormonal therapies. Despite new insights into mechanisms of anti-endocrine therapy resistance, e.g., crosstalk between ERα and Her2/neu, the management of advanced hormone-receptor-positive breast cancers that are resistant to anti-endocrine agents remains a significant challenge. In the present study, we demonstrate that the proteasome inhibitor Bortezomib strongly inhibits ERα and HER2/neu expression, increases expression of cyclin-dependent kinase inhibitors, inhibits expression of multiple genes associated with poor prognosis in ERα+ breast cancer patients and induces cell death in ER+ breast cancer cells in both the presence and absence of functional p53. Although Bortezomib increased the levels of p53 and increased the expression of pro-apoptotic target genes in ERα+ breast cancer cells harboring wild-type p53, Bortezomib also exerts anti-tumoral effects on ERα+ breast cancer cells through suppression of ERα expression and inhibition of PI3K/Akt/mammalian target of rapamycin (mTOR) and ERK signaling independently of functional p53. These findings suggest that Bortezomib might have the potential to improve the management of anti-endocrine therapy resistant ERα+ breast cancers independently of their p53 status.

  1. Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials.

    PubMed

    Jones, S M; Jones, T A; Bell, P L; Taylor, M J

    2001-04-01

    The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP. PMID:11423215

  2. Compound gravity receptor polarization vectors evidenced by linear vestibular evoked potentials.

    PubMed

    Jones, S M; Jones, T A; Bell, P L; Taylor, M J

    2001-04-01

    The utricle and saccule are gravity receptor organs of the vestibular system. These receptors rely on a high-density otoconial membrane to detect linear acceleration and the position of the cranium relative to Earth's gravitational vector. The linear vestibular evoked potential (VsEP) has been shown to be an effective non-invasive functional test specifically for otoconial gravity receptors (Jones et al., 1999). Moreover, there is some evidence that the VsEP can be used to independently test utricular and saccular function (Taylor et al., 1997; Jones et al., 1998). Here we characterize compound macular polarization vectors for the utricle and saccule in hatchling chickens. Pulsed linear acceleration stimuli were presented in two axes, the dorsoventral (DV, +/- Z axis) to isolate the saccule, and the interaural (IA, +/- Y axis) to isolate the utricle. Traditional signal averaging was used to resolve responses recorded from the surface of the skull. Latency and amplitude of eighth nerve components of the linear VsEP were measured. Gravity receptor responses exhibited clear preferences for one stimulus direction in each axis. With respect to each utricular macula, lateral translation in the IA axis produced maximum ipsilateral response amplitudes with substantially greater amplitude intensity (AI) slopes than medially directed movement. Downward caudal motions in the DV axis produced substantially larger response amplitudes and AI slopes. The results show that the macula lagena does not contribute to the VsEP compound polarization vectors of the sacculus and utricle. The findings suggest further that preferred compound vectors for the utricle depend on the pars externa (i.e. lateral hair cell field) whereas for the saccule they depend on pars interna (i.e. superior hair cell fields). These data provide evidence that maculae saccule and utricle can be selectively evaluated using the linear VsEP.

  3. Regulation and localization of transient receptor potential melastatin 2 in rat uterus.

    PubMed

    Ahn, Changhwan; Yang, Hyun; Hong, Eui-Ju; Jeung, Eui-Bae

    2014-10-01

    The transient receptor potential channels are membrane-binding proteins that are nonselectively permeable for cations, such as Ca(2+) and Mg(2+), in numerous mammalian cells. The extracellular or intracellular ions play key roles in physiological functions including muscle contraction, cytokine production, insulin release, and apoptosis. Although transient receptor potential melastatin (TRPM) channels are implicated in nonreproductive tissues, the presence of TRPM2 has been reported in endometrium of uterus. To examine whether the expression of TRPM2 gene in uterus is due to gonadal steroid hormones or hormone-independent effect, the uterine TRPM2 gene was monitored in uterus of mature rat during estrous cycle and of immature rat after treatment with gonadal steroid estrogen (E2), progesterone (P4) with/without estrogen receptor antagonist Imperial Chemical Industries (ICI) 182780. We examined real-time polymerase chain reaction, Western blot, and immunohistochemistry to demonstrate the expression and localization of the uterine TRPM2 gene. The level of TRPM2 messenger RNA and protein are dramatically induced at proestrus, then dropped to base line levels at metestrus, and restored its level at diestrus. The results imply that uterine TRPM2 expression levels are regulated by gonadal steroid hormone E2. Moreover, the E2-induced TRPM2 expression is inhibited by cotreatment with ICI 182780 or P4. Furthermore, the immune-reactive TRPM2 is observed in myometrium and stromal cell of endometrium and also showed alterations in TRPM2 expression during estrus cycle. This study suggests that TRPM2 may be involved in calcium absorption or uterine contraction and the latter may be related to implantation or labor by endogenous sex steroid hormones.

  4. Transient receptor potential channel A1 and noxious cold responses in rat cutaneous nociceptors.

    PubMed

    Dunham, J P; Leith, J L; Lumb, B M; Donaldson, L F

    2010-02-17

    The role of transient receptor potential channel A1 (TRPA1) in noxious cold sensation remains unclear. Some data support the hypothesis that TRPA1 is a transducer of noxious cold whilst other data contest it. In this study we investigated the role of TRPA1 in cold detection in cutaneous nociceptors in vivo using complementary experimental approaches. We used noxious withdrawal reflex electromyography, and single fibre recordings in vivo, to test the hypothesis that TRPA1-expressing primary afferents mediate noxious cold responses in anaesthetised rats. TRPV1 and TRPM8 agonists sensitise their cognate receptors to heat and cold stimuli respectively. Herein we show that the TRPA1 agonist cinnamaldehyde applied to the skin in anaesthetised rats did not sensitise noxious cold evoked hind limb withdrawal. In contrast, cinnamaldehyde did sensitise the C fibre-mediated noxious heat withdrawal, indicated by a significant drop in the withdrawal temperature. TRPA1 agonist thus sensitised the noxious reflex withdrawal to heat, but not cold. Thermal stimuli also sensitise transient receptor potential (TRP) channels to agonist. Activity evoked by capsaicin in teased primary afferent fibres showed a significant positive correlation with receptive field temperature, in both normal and Freund's complete adjuvant-induced cutaneous inflammation. Altering the temperature of the receptive field did not modulate TRPA1 agonist evoked-activity in cutaneous primary afferents, in either normal or inflamed skin. In addition, block of the TRPA1 channel with Ruthenium Red did not inhibit cold evoked activity in either cinnamaldehyde sensitive or insensitive cold responsive nociceptors. In cinnamaldehyde-sensitive-cold-sensitive afferents, although TRPA1 agonist-evoked activity was totally abolished by Ruthenium Red, cold evoked activity was unaffected by channel blockade. We conclude that these results do not support the hypothesis that TRPA1-expressing cutaneous afferents play an important

  5. Transient receptor potential (TRP) channels as drug targets for diseases of the digestive system

    PubMed Central

    Holzer, Peter

    2011-01-01

    Approximately 20 of the 30 mammalian transient receptor potential (TRP) channel subunits are expressed by specific neurons and cells within the alimentary canal. They subserve important roles in taste, chemesthesis, mechanosensation, pain and hyperalgesia and contribute to the regulation of gastrointestinal motility, absorptive and secretory processes, blood flow, and mucosal homeostasis. In a cellular perspective, TRP channels operate either as primary detectors of chemical and physical stimuli, as secondary transducers of ionotropic or metabotropic receptors, or as ion transport channels. The polymodal sensory function of TRPA1, TRPM5, TRPM8, TRPP2, TRPV1, TRPV3 and TRPV4 enables the digestive system to survey its physical and chemical environment, which is relevant to all processes of digestion. TRPV5 and TRPV6 as well as TRPM6 and TRPM7 contribute to the absorption of Ca2+ and Mg2+, respectively. TRPM7 participates in intestinal pacemaker activity, and TRPC4 transduces muscarinic acetylcholine receptor activation to smooth muscle contraction. Changes in TRP channel expression or function are associated with a variety of diseases/disorders of the digestive system, notably gastro-esophageal reflux disease, inflammatory bowel disease, pain and hyperalgesia in heartburn, functional dyspepsia and irritable bowel syndrome, cholera, hypomagnesemia with secondary hypocalcemia, infantile hypertrophic pyloric stenosis, esophageal, gastrointestinal and pancreatic cancer, and polycystic liver disease. These implications identify TRP channels as promising drug targets for the management of a number of gastrointestinal pathologies. As a result, major efforts are put into the development of selective TRP channel agonists and antagonists and the assessment of their therapeutic potential. PMID:21420431

  6. The therapeutic potential of nicotinic acetylcholine receptor agonists for pain control.

    PubMed

    Decker, M W; Meyer, M D; Sullivan, J P

    2001-10-01

    Due to the limitations of currently available analgesics, a number of novel alternatives are currently under investigation, including neuronal nicotinic acetylcholine receptor (nAChR) agonists. During the 1990s, the discovery of the antinociceptive properties of the potent nAChR agonist epibatidine in rodents sparked interest in the analgesic potential of this class of compounds. Although epibatidine also has several mechanism-related toxicities, the identification of considerable nAChR diversity suggested that the toxicities and therapeutic actions of the compound might be mediated by distinct receptor subtypes. Consistent with this view, a number of novel nAChR agonists with antinociceptive activity and improved safety profiles in preclinical models have now been identified, including A-85380, ABT-594, DBO-83, SIB-1663 and RJR-2403. Of these, ABT-594 is the most advanced and is currently in Phase II clinical evaluation. Nicotinically-mediated antinociception has been demonstrated in a variety of rodent pain models and is likely mediated by the activation of descending inhibitory pathways originating in the brainstem with the predominant high-affinity nicotine site in brain, the alpha4beta2 subtype, playing a critical role. Thus, preclinical findings suggest that nAChR agonists have the potential to be highly efficacious treatments in a variety of pain states. However, clinical proof-of-principle studies will be required to determine if nAChR agonists are active in pathological pain.

  7. Cholinergic modulation by opioid receptor ligands: potential application to Alzheimer's disease.

    PubMed

    Motel, William C; Coop, Andrew; Cunningham, Christopher W

    2013-03-01

    Morphinans have a storied history in medicinal chemistry as pain management drugs but have received attention as modulators of cholinergic signaling for the treatment of Alzheimer's Disease (AD). Galantamine is a reversible, competitive acetylcholinesterase (AChE) inhibitor and allosteric potentiating ligand of nicotinic acetylcholine receptors (nAChR-APL) that shares many common structural elements with morphinan-based opioids. The structurally diverse opioids codeine and eseroline, like galantamine, are also nAChR-APL that have greatly diminished affinity for AChE, representing potential lead compounds for selective nAChR-APL development. In accordance with the emerging repurposing trend of evaluating known compounds for novel pharmacological activity, ongoing research on augmentation of cholinergic signaling that has been aided by the use of opioids will be reviewed. PMID:22931533

  8. Metabotropic glutamate receptor agonists potentiate a slow afterdepolarization in CNS neurons

    NASA Technical Reports Server (NTRS)

    Zheng, F.; Gallagher, J. P.

    1992-01-01

    We have previously reported that, in the rat dorsolateral septal nucleus (DLSN), metabotropic glutamate receptor (met-GluR) agonists evoked a slow depolarization accompanied by an increase in membrane conductance and burst firing. We have speculated that the burst firing elicited by met-GluR agonists may be due to activation or enhancement of a non-specific cation current, which exists in some DLSN neurons. Now we report that a slow afterdepolarization (sADP) mediated by a non-specific cation current was potentiated by both 1S,3R-ACPD and quisqualate. In addition, met-GluR agonists unmask a sADP in DLSN neurons which did not show a sADP under control conditions. Our data suggest that a non-specific cation current can be potentiated by activation of the met-GluR.

  9. Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases.

    PubMed

    Sadek, Bassem; Saad, Ali; Sadeq, Adel; Jalal, Fakhreya; Stark, Holger

    2016-10-01

    The potential contributions of the brain histaminergic system in neurodegenerative diseases, and the possiblity of histamine-targeting treatments is attracting considerable interests. The histamine H3 receptor (H3R) is expressed mainly in the central nervous system, and is, consequently, an attractive pharmacological target. Although recently described clinical trials have been disappointing in attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCH), numerous H3R antagonists, including pitolisant, demonstrate potential in the treatment of narcolepsy, excessive daytime sleepiness associated with cognitive impairment, epilepsy, and Alzheimer's disease (AD). This review focuses on the recent preclinical as well as clinical results that support the relevance of H3R antagonists for the treatment of cognitive symptoms in neuropsychiatric diseases, namely AD, epilepsy and SCH. The review summarizes the role of histaminergic neurotransmission with focus on these brain disorders, as well as the effects of numerous H3R antagonists on animal models and humans.

  10. Group I and group II metabotropic glutamate receptor allosteric modulators as novel potential antipsychotics

    PubMed Central

    Walker, Adam G.; Conn, P. Jeffrey

    2014-01-01

    Recently, there has been a shift in the schizophrenia field focusing on restoring glutamate signaling. Extensive preclinical data suggests that mGlu5 PAMs could have efficacy in all three symptom domains but there is concern of potential adverse effects. New insights into mechanisms underlying this toxicity may provide a path for discovery of safe mGlu5 PAMs. Genetic mutations in mGlu1 have been described in schizophrenics creating interest in this receptor as a therapeutic target. Preclinical data demonstrated the antipsychotic potential of of mGlu2/3 agonists but clinical trials were not successful. However, studies have suggested that mGlu2 is the subtype mediating antipsychotic effects and selective mGlu2 PAMs are now in clinical development. Finally, recent genetic studies suggest mGlu3 modulators may be pro-cognitive. PMID:25462291

  11. Group I and group II metabotropic glutamate receptor allosteric modulators as novel potential antipsychotics.

    PubMed

    Walker, Adam G; Conn, P Jeffrey

    2015-02-01

    Recently, there has been a shift in the schizophrenia field focusing on restoring glutamate signaling. Extensive preclinical data suggests that mGlu5 PAMs could have efficacy in all three symptom domains but there is concern of potential adverse effects. New insights into mechanisms underlying this toxicity may provide a path for discovery of safe mGlu5 PAMs. Genetic mutations in mGlu1 have been described in schizophrenics creating interest in this receptor as a therapeutic target. Preclinical data demonstrated the antipsychotic potential of mGlu2/3 agonists but clinical trials were not successful. However, studies have suggested that mGlu2 is the subtype mediating antipsychotic effects and selective mGlu2 PAMs are now in clinical development. Finally, recent genetic studies suggest mGlu3 modulators may be pro-cognitive. PMID:25462291

  12. Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases.

    PubMed

    Sadek, Bassem; Saad, Ali; Sadeq, Adel; Jalal, Fakhreya; Stark, Holger

    2016-10-01

    The potential contributions of the brain histaminergic system in neurodegenerative diseases, and the possiblity of histamine-targeting treatments is attracting considerable interests. The histamine H3 receptor (H3R) is expressed mainly in the central nervous system, and is, consequently, an attractive pharmacological target. Although recently described clinical trials have been disappointing in attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCH), numerous H3R antagonists, including pitolisant, demonstrate potential in the treatment of narcolepsy, excessive daytime sleepiness associated with cognitive impairment, epilepsy, and Alzheimer's disease (AD). This review focuses on the recent preclinical as well as clinical results that support the relevance of H3R antagonists for the treatment of cognitive symptoms in neuropsychiatric diseases, namely AD, epilepsy and SCH. The review summarizes the role of histaminergic neurotransmission with focus on these brain disorders, as well as the effects of numerous H3R antagonists on animal models and humans. PMID:27363923

  13. Identification of Metabotropic Glutamate Receptor Subtype 5 Potentiators Using Virtual High-Throughput Screening

    PubMed Central

    2010-01-01

    Selective potentiators of glutamate response at metabotropic glutamate receptor subtype 5 (mGluR5) have exciting potential for the development of novel treatment strategies for schizophrenia. A total of 1,382 compounds with positive allosteric modulation (PAM) of the mGluR5 glutamate response were identified through high-throughput screening (HTS) of a diverse library of 144,475 substances utilizing a functional assay measuring receptor-induced intracellular release of calcium. Primary hits were tested for concentration-dependent activity, and potency data (EC50 values) were used for training artificial neural network (ANN) quantitative structure−activity relationship (QSAR) models that predict biological potency from the chemical structure. While all models were trained to predict EC50, the quality of the models was assessed by using both continuous measures and binary classification. Numerical descriptors of chemical structure were used as input for the machine learning procedure and optimized in an iterative protocol. The ANN models achieved theoretical enrichment ratios of up to 38 for an independent data set not used in training the model. A database of ∼450,000 commercially available drug-like compounds was targeted in a virtual screen. A set of 824 compounds was obtained for testing based on the highest predicted potency values. Biological testing found 28.2% (232/824) of these compounds with various activities at mGluR5 including 177 pure potentiators and 55 partial agonists. These results represent an enrichment factor of 23 for pure potentiation of the mGluR5 glutamate response and 30 for overall mGluR5 modulation activity when compared with those of the original mGluR5 experimental screening data (0.94% hit rate). The active compounds identified contained 72% close derivatives of previously identified PAMs as well as 28% nontrivial derivatives of known active compounds. PMID:20414370

  14. Potential role of transient receptor potential channel M5 in sensing putative pheromones in mouse olfactory sensory neurons.

    PubMed

    Oshimoto, Arisa; Wakabayashi, Yoshihiro; Garske, Anna; Lopez, Roberto; Rolen, Shane; Flowers, Michael; Arevalo, Nicole; Restrepo, Diego

    2013-01-01

    Based on pharmacological studies of chemosensory transduction in transient receptor potential channel M5 (TRPM5) knockout mice it was hypothesized that this channel is involved in transduction for a subset of putative pheromones in mouse olfactory sensory neurons (OSNs). Yet, in the same study an electroolfactogram (EOG) in the mouse olfactory epithelium showed no significant difference in the responses to pheromones (and odors) between wild type and TRPM5 knockout mice. Here we show that the number of OSNs expressing TRPM5 is increased by unilateral naris occlusion. Importantly, EOG experiments show that mice lacking TRPM5 show a decreased response in the occluded epithelia to putative pheromones as opposed to wild type mice that show no change upon unilateral naris occlusion. This evidence indicates that under decreased olfactory sensory input TRPM5 plays a role in mediating putative pheromone transduction. Furthermore, we demonstrate that cyclic nucleotide gated channel A2 knockout (CNGA2-KO) mice that show substantially decreased or absent responses to odors and pheromones also have elevated levels of TRPM5 compared to wild type mice. Taken together, our evidence suggests that TRPM5 plays a role in mediating transduction for putative pheromones under conditions of reduced chemosensory input.

  15. Evaluation of the abuse potential of AM281, a new synthetic cannabinoid CB1 receptor antagonist.

    PubMed

    Botanas, Chrislean Jun; de la Peña, June Bryan; Dela Pena, Irene Joy; Tampus, Reinholdgher; Kim, Hee Jin; Yoon, Seong Shoon; Seo, Joung-Wook; Jeong, Eun Ju; Cheong, Jae Hoon

    2015-11-01

    AM281 (1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide) is a new synthetic cannabinoid CB1 receptor antagonist. Similar to other cannabinoid antagonists, AM281 has been suggested to have therapeutic indications. However, recent reports have suggested that cannabinoid CB1 receptor antagonists may share similar behavioral effects with other drugs of abuse such as cocaine and amphetamine. These reports cast doubts on the safety profile of AM281. Thus, in the present study we evaluated the abuse potential (rewarding and reinforcing effects) of AM281 through two of the most widely used animal models for assessing the abuse potential of drugs: the conditioned place preference (CPP) and self-administration (SA) tests. Experiments were performed in Sprague-Dawley rats in various dosages [CPP (0.1, 0.5 or 2.5mg/kg), SA (0.005, 0.025 or 0.1mg/kg/infusion)]. We also delved into the consequences of repeated drug exposure on the subsequent response to the drug. Thus, parallel experiments were carried out in rats pretreated with AM281 for 7 or 14 days. Our findings indicated that AM281, at any dose, did not induce CPP and SA in drug-naïve rats. Interestingly, significant CPP (0.5mg/kg of AM281), but not SA, was observed in 14 days pretreated rats. These observations suggest that AM281 per se has no or minimal rewarding and reinforcing properties, but alterations in neuronal functions and behavior due to repeated AM281 exposure may contribute in part to the abuse potential of this drug. In view of this finding, we advocate the careful use, monitoring, and dispensation of AM281.

  16. Regulation of the transient receptor potential channel TRPM3 by phosphoinositides.

    PubMed

    Tóth, Balázs I; Konrad, Maik; Ghosh, Debapriya; Mohr, Florian; Halaszovich, Christian R; Leitner, Michael G; Vriens, Joris; Oberwinkler, Johannes; Voets, Thomas

    2015-07-01

    The transient receptor potential (TRP) channel TRPM3 is a calcium-permeable cation channel activated by heat and by the neurosteroid pregnenolone sulfate (PregS). TRPM3 is highly expressed in sensory neurons, where it plays a key role in heat sensing and inflammatory hyperalgesia, and in pancreatic β cells, where its activation enhances glucose-induced insulin release. However, despite its functional importance, little is known about the cellular mechanisms that regulate TRPM3 activity. Here, we provide evidence for a dynamic regulation of TRPM3 by membrane phosphatidylinositol phosphates (PIPs). Phosphatidylinositol 4,5-bisphosphate (PI[4,5]P2) and ATP applied to the intracellular side of excised membrane patches promote recovery of TRPM3 from desensitization. The stimulatory effect of cytosolic ATP on TRPM3 reflects activation of phosphatidylinositol kinases (PI-Ks), leading to resynthesis of PIPs in the plasma membrane. Various PIPs directly enhance TRPM3 activity in cell-free inside-out patches, with a potency order PI(3,4,5)P3 > PI(3,5)P2 > PI(4,5)P2 ≈ PI(3,4)P2 > PI(4)P. Conversely, TRPM3 activity is rapidly and reversibly inhibited by activation of phosphatases that remove the 5-phosphate from PIPs. Finally, we show that recombinant TRPM3, as well as the endogenous TRPM3 in insuloma cells, is rapidly and reversibly inhibited by activation of phospholipase C-coupled muscarinic acetylcholine receptors. Our results reveal basic cellular mechanisms whereby membrane receptors can regulate TRPM3 activity. PMID:26123194

  17. Triphenyl phosphate-induced developmental toxicity in zebrafish: Potential role of the retinoic acid receptor

    PubMed Central

    Isales, Gregory M.; Hipszer, Rachel A.; Raftery, Tara D.; Chen, Albert; Stapleton, Heather M.; Volz, David C.

    2015-01-01

    Using zebrafish as a model, we previously reported that developmental exposure to triphenyl phosphate (TPP) – a high-production volume organophosphate-based flame retardant – results in dioxin-like cardiac looping impairments that are independent of the aryl hydrocarbon receptor. Using a pharmacologic approach, the objective of this study was to investigate the potential role of retinoic acid receptor (RAR) – a nuclear receptor that regulates vertebrate heart morphogenesis – in mediating TPP-induced developmental toxicity in zebrafish. We first revealed that static exposure of zebrafish from 5-72 hours post-fertilization (hpf) to TPP in the presence of non-toxic concentrations of an RAR antagonist (BMS493) significantly enhanced TPP-induced toxicity (relative to TPP alone), even though identical non-toxic BMS493 concentrations mitigated retinoic acid (RA)-induced toxicity. BMS493-mediated enhancement of TPP toxicity was not a result of differential TPP uptake or metabolism, as internal embryonic doses of TPP and diphenyl phosphate (DPP) – a primary TPP metabolite - were not different in the presence or absence of BMS493. Using real-time PCR, we then quantified the relative change in expression of cytochrome P450 26a1 (cyp26a1) – a major target gene for RA-induced RAR activation in zebrafish – and found that RA and TPP exposure resulted in a ∼5-fold increase and decrease in cyp26a1 expression, respectively, relative to vehicle-exposed embryos. To address whether TPP may interact with human RARs, we then exposed Chinese hamster ovary cells stably transfected with chimeric human RARα-, RARβ-, or RARγ to TPP in the presence of RA, and found that TPP significantly inhibited RA-induced luciferase activity in a concentration-dependent manner. Overall, our findings suggest that zebrafish RARs may be involved in mediating TPP-induced developmental toxicity, a mechanism of action that may have relevance to humans. PMID:25725299

  18. Human Milk Contains Novel Glycans That Are Potential Decoy Receptors for Neonatal Rotaviruses*

    PubMed Central

    Yu, Ying; Lasanajak, Yi; Song, Xuezheng; Hu, Liya; Ramani, Sasirekha; Mickum, Megan L.; Ashline, David J.; Prasad, B. V. Venkataram; Estes, Mary K.; Reinhold, Vernon N.; Cummings, Richard D.; Smith, David F.

    2014-01-01

    Human milk contains a rich set of soluble, reducing glycans whose functions and bioactivities are not well understood. Because human milk glycans (HMGs) have been implicated as receptors for various pathogens, we explored the functional glycome of human milk using shotgun glycomics. The free glycans from pooled milk samples of donors with mixed Lewis and Secretor phenotypes were labeled with a fluorescent tag and separated via multidimensional HPLC to generate a tagged glycan library containing 247 HMG targets that were printed to generate the HMG shotgun glycan microarray (SGM). To investigate the potential role of HMGs as decoy receptors for rotavirus (RV), a leading cause of severe gastroenteritis in children, we interrogated the HMG SGM with recombinant forms of VP8* domains of the RV outer capsid spike protein VP4 from human neonatal strains N155(G10P[11]) and RV3(G3P[6]) and a bovine strain, B223(G10P[11]). Glycans that were bound by RV attachment proteins were selected for detailed structural analyses using metadata-assisted glycan sequencing, which compiles data on each glycan based on its binding by antibodies and lectins before and after exo- and endo-glycosidase digestion of the SGM, coupled with independent MSn analyses. These complementary structural approaches resulted in the identification of 32 glycans based on RV VP8* binding, many of which are novel HMGs, whose detailed structural assignments by MSn are described in a companion report. Although sialic acid has been thought to be important as a surface receptor for RVs, our studies indicated that sialic acid is not required for binding of glycans to individual VP8* domains. Remarkably, each VP8* recognized specific glycan determinants within a unique subset of related glycan structures where specificity differences arise from subtle differences in glycan structures. PMID:25048705

  19. [Nicotine effects on mitochondria membrane potential: participation of nicotinic acetylcholine receptors].

    PubMed

    Gergalova, G L; Skok, M V

    2011-01-01

    The effect of nicotine on the mouse liver mitochondria was studied by fluorescent flow cytometry. Mice consumed nicotine during 65 days; alternatively, nicotine was added to isolated mitochondria. Mitochondria of nicotine-treated mice had significantly lower basic levels of membrane potential and granularity as compared to those of the control group. Pre-incubation of the isolated mitochondria with nicotine prevented from dissipation of their membrane potential stimulated with 0.8 microM CaCl2 depending on the dose, and this effect was strengthened by the antagonist of alpha7 nicotinic receptors (alpha7 nAChR) methyllicaconitine. Mitochondria of mice intravenously injected with the antibodies against alpha7 nAChR demonstrated lower levels of membrane potential. Introduction of nicotine, choline, acetylcholine or synthetic alpha7 nAChR agonist PNU 282987 into the incubation medium inhibited Ca2+ accumulation in mitochondria, although the doses of agonists were too low to activate the alpha7 nAChR ion channel. It is concluded that nicotine consumption worsens the functional state of mitochondria by affecting their membrane potential and granularity, and this effect, at least in part, is mediated by alpha7 nAChR desensitization.

  20. Antidepressant/anxiolytic potential and adverse effect liabilities of melanin-concentrating hormone receptor 1 antagonists in animal models.

    PubMed

    Chaki, Shigeyuki; Shimazaki, Toshiharu; Nishiguchi, Mariko; Funakoshi, Takeo; Iijima, Michihiko; Ito, Akie; Kanuma, Kosuke; Sekiguchi, Yoshinori

    2015-08-01

    Melanin-concentrating hormone receptor 1 (MCH1 receptor) is known to be involved in the control of mood and stress, in addition to the regulation of feeding. Here, we report further evidence that the blockade of the MCH1 receptor exhibits antidepressant and anxiolytic-like effects in a variety of animal models using TASP0382650 and TASP0489838, newly synthesized MCH1 receptor antagonists, with different scaffolds. Both TASP0382650 and TASP0489838 exhibited high affinities for human MCH1 receptor with IC50 values of 7.13 and 3.80nM, respectively. Both compounds showed potent antagonist activities at the MCH1 receptor, as assessed using MCH-increased [(35)S]GTPγS binding to human MCH1 receptor and an MCH-induced [Ca(2+)]i assay in rat MCH1 receptor expressing cells. In contrast, neither TASP0382650 nor TASP0489838 showed an affinity for the MCH2 receptor, another MCH receptor subtype. The oral administration of TASP0382650 or TASP0489838 significantly reduced the immobility time during the forced swimming test in rats, and reduced hyperemotionality induced by an olfactory bulbectomy, both of which are indicative of an antidepressant-like potential. In the olfactory bulbectomy model, the antidepressant effect of TASP0382650 appeared following a single administration, suggesting a faster onset of action, compared with current medications. Moreover, both TASP0382650 and TASP0489838 exhibited anxiolytic effects in several animal models of anxiety. In contrast, both TASP0382650 and TASP0489838 did not affect spontaneous locomotor activity, motor function, spatial memory during the Morris water maze task, or the convulsion threshold to pentylenetetrazole. These findings provide additional evidence that the blockade of the MCH1 receptor exhibits antidepressant- and anxiolytic activities with no adverse effects in experimental animal models.

  1. Synthesis and In Vitro Evaluation of Novel Nortropane Derivatives as Potential Radiotracers for Muscarinic M2 Receptors

    PubMed Central

    Knol, Remco J. J.; van den Bos, Jan C.; Janssen, Anton G. M.; de Bruin, Kora; van Eck-Smit, Berthe L. F.; Booij, Jan

    2011-01-01

    Disturbances of the cerebral cholinergic neurotransmitter system are present in neurodegenerative disorders. SPECT or PET imaging, using radiotracers that selectively target muscarinic receptor subtypes, may be of value for in vivo evaluation of such conditions. 6β-acetoxynortropane, a potent muscarinic M2 receptor agonist, has previously demonstrated nanomolar affinity and high selectivity for this receptor. Based on this compound we synthesized four nortropane derivatives that are potentially suitable for SPECT imaging of the M2 receptor. 6β-acetoxynortropane and the novel derivatives were tested in vitro for affinity to the muscarinic M1−3 receptors. The original 6β-acetoxynortropane displayed high affinity (Ki = 70–90 nM) to M2 receptors and showed good selectivity ratios to the M1 (65-fold ratio) and the M3 (70-fold ratio) receptors. All new derivatives showed reduced affinity to the M2 subtype and loss of subtype selectivity. It is therefore concluded that the newly synthesized derivatives are not suitable for human SPECT imaging of M2 receptors. PMID:21755053

  2. Transient Receptor Potential Melastatin-3 (TRPM3) Mediates Nociceptive-Like Responses in Hydra vulgaris

    PubMed Central

    Malafoglia, Valentina; Traversetti, Lorenzo; Del Grosso, Floriano; Scalici, Massimiliano; Lauro, Filomena; Russo, Valeria; Persichini, Tiziana; Salvemini, Daniela; Mollace, Vincenzo; Fini, Massimo; Raffaeli, William

    2016-01-01

    The ability of mammals to feel noxious stimuli lies in a heterogeneous group of primary somatosensory neurons termed nociceptors, which express specific membrane receptors, such as the Transient Receptor Potential (TRP) family. Here, we show that one of the most important nociceptive-like pathways is conserved in the freshwater coelenterate Hydra vulgaris, the most primitive organism possessing a nervous system. In particular, we found that H. vulgaris expresses TRPM3, a nociceptor calcium channel involved in the detection of noxious heat in mammals. Furthermore, we detected that both heat shock and TRPM3 specific agonist (i.e., pregnenolone sulfate) induce the modulation of the heat shock protein 70 (HSP70) and the nitric oxide synthase (NOS), two genes activated by TRP-mediated heat painful stimuli in mammals. As expected, these effects are inhibited by a TRPM3 antagonist (i.e., mefenamic acid). Interestingly, the TRPM3 agonist and heat shock also induce the expression of nuclear transcription erythroid 2-related factor (Nrf2) and superoxide dismutase (SOD), known markers of oxidative stress; noteworthy gene expression was also inhibited by the TRPM3 antagonist. As a whole, our results demonstrate the presence of conserved molecular oxidative/nociceptive-like pathways at the primordial level of the animal kingdom. PMID:26974325

  3. Fibroblast Growth Factor Receptor-2 Expression in Thyroid Tumor Progression: Potential Diagnostic Application

    PubMed Central

    Redler, Adriano; Di Rocco, Giorgio; Giannotti, Domenico; Frezzotti, Francesca; Bernieri, Maria Giulia; Ceccarelli, Simona; D’Amici, Sirio; Vescarelli, Enrica; Mitterhofer, Anna Paola; Angeloni, Antonio; Marchese, Cinzia

    2013-01-01

    Fibroblast growth factor receptor-2 (FGFR-2) plays an important role in tumorigenesis. In thyroid cancer it has been observed a FGFR-2 down-modulation, but the role of this receptor has not been yet clarified. Therefore, we decided to examine the expression of both FGFR-2 isoform, FGFR-2-IIIb and FGFR-2-IIIc, in different histological thyroid variants such as hyperplasia, follicular adenoma and papillary carcinoma. Immunohistochemistry and quantitative Real-Time PCR analyses were performed on samples of hyperplasia, follicular adenoma and papillary carcinoma, compared with normal thyroid tissue. Thyroid hyperplasia did not show statistically significant reduction in FGFR-2 protein and mRNA levels. Interestingly, in both follicular adenoma and papillary carcinoma samples we observed a strongly reduced expression of both FGFR-2 isoforms. We speculate that FGFR-2 down-modulation might be an early event in thyroid carcinogenesis. Furthermore, we suggest the potential use of FGFR-2 as an early marker for thyroid cancer diagnosis. PMID:23977259

  4. Fibroblast growth factor receptor-2 expression in thyroid tumor progression: potential diagnostic application.

    PubMed

    Redler, Adriano; Di Rocco, Giorgio; Giannotti, Domenico; Frezzotti, Francesca; Bernieri, Maria Giulia; Ceccarelli, Simona; D'Amici, Sirio; Vescarelli, Enrica; Mitterhofer, Anna Paola; Angeloni, Antonio; Marchese, Cinzia

    2013-01-01

    Fibroblast growth factor receptor-2 (FGFR-2) plays an important role in tumorigenesis. In thyroid cancer it has been observed a FGFR-2 down-modulation, but the role of this receptor has not been yet clarified. Therefore, we decided to examine the expression of both FGFR-2 isoform, FGFR-2-IIIb and FGFR-2-IIIc, in different histological thyroid variants such as hyperplasia, follicular adenoma and papillary carcinoma. Immunohistochemistry and quantitative Real-Time PCR analyses were performed on samples of hyperplasia, follicular adenoma and papillary carcinoma, compared with normal thyroid tissue. Thyroid hyperplasia did not show statistically significant reduction in FGFR-2 protein and mRNA levels. Interestingly, in both follicular adenoma and papillary carcinoma samples we observed a strongly reduced expression of both FGFR-2 isoforms. We speculate that FGFR-2 down-modulation might be an early event in thyroid carcinogenesis. Furthermore, we suggest the potential use of FGFR-2 as an early marker for thyroid cancer diagnosis. PMID:23977259

  5. Physiological functions of transient receptor potential channels in pulmonary arterial smooth muscle cells.

    PubMed

    Yang, Xiao-Ru; Lin, Mo-Jun; Sham, James S K

    2010-01-01

    The transient receptor potential (TRP) gene superfamily, which consists of 7 subfamilies with at least 28 mammalian homologues, is known to encode a wide variety of cation channels with diverse biophysical properties, activation mechanisms, and physiological functions. Recent studies have identified multiple TRP channel subtypes, belonging to the canonical (TRPC), melastatin-related (TRPM), and vanilloid-related (TRPV) subfamilies, in pulmonary arterial smooth muscle cells (PASMCs). They operate as specific Ca(2+) pathways responsive to stimuli, including Ca(2+) store depletion, receptor activation, reactive oxygen species, growth factors, and mechanical stress. Increasing evidence suggests that these channels play crucial roles in agonist-induced pulmonary vasoconstriction, hypoxic pulmonary vasoconstriction, smooth muscle cell proliferation, vascular remodeling, and pulmonary arterial hypertension. This chapter highlighted and discussed these putative physiological functions of TRP channels in pulmonary vasculatures. Since Ca(2+) ions regulate many cellular processes via specific Ca(2+) signals, future investigations of these novel channels will likely uncover more important regulatory mechanisms of pulmonary vascular functions in health and in disease states. PMID:20204726

  6. Polymodal Transient Receptor Potential Vanilloid (TRPV) Ion Channels in Chondrogenic Cells

    PubMed Central

    Szűcs Somogyi, Csilla; Matta, Csaba; Foldvari, Zsofia; Juhász, Tamás; Katona, Éva; Takács, Ádám Roland; Hajdú, Tibor; Dobrosi, Nóra; Gergely, Pál; Zákány, Róza

    2015-01-01

    Mature and developing chondrocytes exist in a microenvironment where mechanical load, changes of temperature, osmolarity and acidic pH may influence cellular metabolism. Polymodal Transient Receptor Potential Vanilloid (TRPV) receptors are environmental sensors mediating responses through activation of linked intracellular signalling pathways. In chondrogenic high density cultures established from limb buds of chicken and mouse embryos, we identified TRPV1, TRPV2, TRPV3, TRPV4 and TRPV6 mRNA expression with RT-PCR. In both cultures, a switch in the expression pattern of TRPVs was observed during cartilage formation. The inhibition of TRPVs with the non-selective calcium channel blocker ruthenium red diminished chondrogenesis and caused significant inhibition of proliferation. Incubating cell cultures at 41 °C elevated the expression of TRPV1, and increased cartilage matrix production. When chondrogenic cells were exposed to mechanical load at the time of their differentiation into matrix producing chondrocytes, we detected increased mRNA levels of TRPV3. Our results demonstrate that developing chondrocytes express a full palette of TRPV channels and the switch in the expression pattern suggests differentiation stage-dependent roles of TRPVs during cartilage formation. As TRPV1 and TRPV3 expression was altered by thermal and mechanical stimuli, respectively, these are candidate channels that contribute to the transduction of environmental stimuli in chondrogenic cells. PMID:26262612

  7. Transient Receptor Potential Channels Contribute to Pathological Structural and Functional Remodeling After Myocardial Infarction

    PubMed Central

    Davis, Jennifer; Correll, Robert N.; Trappanese, Danielle M.; Hoffman, Nicholas E.; Troupes, Constantine D.; Berretta, Remus M.; Kubo, Hajime; Madesh, Muniswamy; Chen, Xiongwen; Gao, Erhe; Molkentin, Jeffery D.; Houser, Steven R.

    2014-01-01

    Rationale The cellular and molecular basis for post myocardial infarction (MI) structural and functional remodeling is not well understood. Objective To determine if Ca2+ influx through transient receptor potential (canonical) (TRPC) channels contributes to post-MI structural and functional remodeling. Methods and Results TRPC1/3/4/6 channel mRNA increased after MI in mice and was associated with TRPC-mediated Ca2+ entry. Cardiac myocyte specific expression of a dominant negative (dn: loss of function) TRPC4 channel increased basal myocyte contractility and reduced hypertrophy and cardiac structural and functional remodeling after MI while increasing survival. We used adenovirus-mediated expression of TRPC3/4/6 channels in cultured adult feline myocytes (AFMs) to define mechanistic aspects of these TRPC-related effects. TRPC3/4/6 over expression in AFMs induced calcineurin (Cn)-Nuclear Factor of Activated T cells (NFAT) mediated hypertrophic signaling, which was reliant on caveolae targeting of TRPCs. TRPC3/4/6 expression in AFMs increased rested state contractions and increased spontaneous sarcoplasmic reticulum (SR) Ca2+ sparks mediated by enhanced phosphorylation of the ryanodine receptor. TRPC3/4/6 expression was associated with reduced contractility and response to catecholamines during steady state pacing, likely due to enhanced SR Ca2+ leak. Conclusions Ca2+ influx through TRPC channels expressed after MI activates pathological cardiac hypertrophy and reduces contractility reserve. Blocking post-MI TRPC activity improved post-MI cardiac structure and function. PMID:25047165

  8. Calcium Sensing Receptor as a Novel Mediator of Adipose Tissue Dysfunction: Mechanisms and Potential Clinical Implications

    PubMed Central

    Bravo-Sagua, Roberto; Mattar, Pamela; Díaz, Ximena; Lavandero, Sergio; Cifuentes, Mariana

    2016-01-01

    Obesity is currently a serious worldwide public health problem, reaching pandemic levels. For decades, dietary and behavioral approaches have failed to prevent this disease from expanding, and health authorities are challenged by the elevated prevalence of co-morbid conditions. Understanding how obesity-associated diseases develop from a basic science approach is recognized as an urgent task to face this growing problem. White adipose tissue (WAT) is an active endocrine organ, with a crucial influence on whole-body homeostasis. WAT dysfunction plays a key role linking obesity with its associated diseases such as type 2 diabetes mellitus, cardiovascular disease, and some cancers. Among the regulators of WAT physiology, the calcium-sensing receptor (CaSR) has arisen as a potential mediator of WAT dysfunction. Expression of the receptor has been described in human preadipocytes, adipocytes, and the human adipose cell lines LS14 and SW872. The evidence suggests that CaSR activation in the visceral (i.e., unhealthy) WAT is associated with an increased proliferation of adipose progenitor cells and elevated adipocyte differentiation. In addition, exposure of adipose cells to CaSR activators in vitro elevates proinflammatory cytokine expression and secretion. An increased proinflammatory environment in WAT plays a key role in the development of WAT dysfunction that leads to peripheral organ fat deposition and insulin resistance, among other consequences. We propose that CaSR may be one relevant therapeutic target in the struggle to confront the health consequences of the current worldwide obesity pandemic.

  9. Angiotensin receptor-neprilysin inhibitors: clinical potential in heart failure and beyond

    PubMed Central

    Singh, Jagdeep SS; Lang, Chim C

    2015-01-01

    Heart failure remains a major concern across the globe as life expectancies and delivery of health care continue to improve. There has been a dearth of new developments in heart failure therapies in the last decade until last year, with the release of the results from the PARADIGM-HF Trial heralding the arrival of a promising new class of drug, ie, the angiotensin receptor-neprilysin inhibitor. In this review, we discuss the evolution of our incremental understanding of the neurohormonal mechanisms involved in the pathophysiology of heart failure, which has led to our success in modulating its various pathways. We start by examining the renin-angiotensin-aldosterone system, followed by the challenges of modulating the natriuretic peptide system. We then delve deeper into the pharmacology and mechanisms by which angiotensin receptor-neprilysin inhibitors achieve their significant cardiovascular benefits. Finally, we also consider the potential application of this new class of drug in other areas, such as heart failure with preserved ejection fraction, hypertension, patients with renal impairment, and following myocardial infarction. PMID:26082640

  10. Pre-clinical studies in cough research: Role of Transient Receptor Potential (TRP) channels

    PubMed Central

    Grace, Megan S.; Dubuis, Eric; Birrell, Mark A.; Belvisi, Maria G.

    2013-01-01

    Cough is a protective reflex and defence mechanism in healthy individuals, which helps clear excessive secretions and foreign material from the lungs. Cough often presents as the first and most persistent symptom of many respiratory diseases and some non-respiratory disorders, but can also be idiopathic, and is a common respiratory complaint for which medical attention is sought. Chronic cough of various aetiologies is a regular presentation to specialist respiratory clinics, and is reported as a troublesome symptom by a significant proportion of the population. Despite this, the treatment options for cough are limited. The lack of effective anti-tussives likely stems from our incomplete understanding of how the tussive reflex is mediated. However, research over the last decade has begun to shed some light on the mechanisms which provoke cough, and may ultimately provide us with better anti-tussive therapies. This review will focus on the in vitro and in vivo models that are currently used to further our understanding of the sensory innervation of the respiratory tract, and how these nerves are involved in controlling the cough response. Central to this are the Transient Receptor Potential (TRP) ion channels, a family of polymodal receptors that can be activated by such diverse stimuli as chemicals, temperature, osmotic stress, and mechanical perturbation. These ion channels are thought to be molecular pain integrators and targets for novel analgesic agents for the treatment of various pain disorders but some are also being developed as anti-tussives. PMID:23474212

  11. Calcium Sensing Receptor as a Novel Mediator of Adipose Tissue Dysfunction: Mechanisms and Potential Clinical Implications.

    PubMed

    Bravo-Sagua, Roberto; Mattar, Pamela; Díaz, Ximena; Lavandero, Sergio; Cifuentes, Mariana

    2016-01-01

    Obesity is currently a serious worldwide public health problem, reaching pandemic levels. For decades, dietary and behavioral approaches have failed to prevent this disease from expanding, and health authorities are challenged by the elevated prevalence of co-morbid conditions. Understanding how obesity-associated diseases develop from a basic science approach is recognized as an urgent task to face this growing problem. White adipose tissue (WAT) is an active endocrine organ, with a crucial influence on whole-body homeostasis. WAT dysfunction plays a key role linking obesity with its associated diseases such as type 2 diabetes mellitus, cardiovascular disease, and some cancers. Among the regulators of WAT physiology, the calcium-sensing receptor (CaSR) has arisen as a potential mediator of WAT dysfunction. Expression of the receptor has been described in human preadipocytes, adipocytes, and the human adipose cell lines LS14 and SW872. The evidence suggests that CaSR activation in the visceral (i.e., unhealthy) WAT is associated with an increased proliferation of adipose progenitor cells and elevated adipocyte differentiation. In addition, exposure of adipose cells to CaSR activators in vitro elevates proinflammatory cytokine expression and secretion. An increased proinflammatory environment in WAT plays a key role in the development of WAT dysfunction that leads to peripheral organ fat deposition and insulin resistance, among other consequences. We propose that CaSR may be one relevant therapeutic target in the struggle to confront the health consequences of the current worldwide obesity pandemic. PMID:27660614

  12. GLP-1 receptor antagonist as a potential probe for pancreatic {beta}-cell imaging

    SciTech Connect

    Mukai, Eri; Toyoda, Kentaro; Kimura, Hiroyuki; Kawashima, Hidekazu; Fujimoto, Hiroyuki; Ueda, Masashi; Temma, Takashi; Hirao, Konomu; Nagakawa, Kenji; Saji, Hideo; Inagaki, Nobuya

    2009-11-20

    We examined exendin(9-39), an antagonist of glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), as a potential probe for imaging of pancreatic {beta}-cells. To evaluate in vitro receptor specificity, binding assay was performed using dispersed mouse islet cells. Binding assay showed competitive inhibition of [{sup 125}I]BH-exendin(9-39) binding by non-radioactive exendin(9-39). To assess in vivo selectivity, the biodistribution was evaluated by intravenous administration of [{sup 125}I]BH-exendin(9-39) to mice. Radioactivity of harvested pancreas reached highest levels at 60 and 120 min among organs examined except lung. Pre-administration of excess non-radioactive exendin(9-39) remarkably and specifically blocked the radioactivity of pancreas. After [{sup 125}I]BH-exendin(9-39) injection into transgenic mice with pancreatic {beta}-cells expressing GFP, fluorescent and radioactive signals of sections of pancreas were evaluated with an image analyzer. Imaging analysis showed that the fluorescent GFP signals and the radioactive signals were correspondingly located. Thus, the GLP-1R antagonist exendin(9-39) may serve as a useful probe for pancreatic {beta}-cell imaging.

  13. Calcium Sensing Receptor as a Novel Mediator of Adipose Tissue Dysfunction: Mechanisms and Potential Clinical Implications

    PubMed Central

    Bravo-Sagua, Roberto; Mattar, Pamela; Díaz, Ximena; Lavandero, Sergio; Cifuentes, Mariana

    2016-01-01

    Obesity is currently a serious worldwide public health problem, reaching pandemic levels. For decades, dietary and behavioral approaches have failed to prevent this disease from expanding, and health authorities are challenged by the elevated prevalence of co-morbid conditions. Understanding how obesity-associated diseases develop from a basic science approach is recognized as an urgent task to face this growing problem. White adipose tissue (WAT) is an active endocrine organ, with a crucial influence on whole-body homeostasis. WAT dysfunction plays a key role linking obesity with its associated diseases such as type 2 diabetes mellitus, cardiovascular disease, and some cancers. Among the regulators of WAT physiology, the calcium-sensing receptor (CaSR) has arisen as a potential mediator of WAT dysfunction. Expression of the receptor has been described in human preadipocytes, adipocytes, and the human adipose cell lines LS14 and SW872. The evidence suggests that CaSR activation in the visceral (i.e., unhealthy) WAT is associated with an increased proliferation of adipose progenitor cells and elevated adipocyte differentiation. In addition, exposure of adipose cells to CaSR activators in vitro elevates proinflammatory cytokine expression and secretion. An increased proinflammatory environment in WAT plays a key role in the development of WAT dysfunction that leads to peripheral organ fat deposition and insulin resistance, among other consequences. We propose that CaSR may be one relevant therapeutic target in the struggle to confront the health consequences of the current worldwide obesity pandemic. PMID:27660614

  14. Calcium Sensing Receptor as a Novel Mediator of Adipose Tissue Dysfunction: Mechanisms and Potential Clinical Implications.

    PubMed

    Bravo-Sagua, Roberto; Mattar, Pamela; Díaz, Ximena; Lavandero, Sergio; Cifuentes, Mariana

    2016-01-01

    Obesity is currently a serious worldwide public health problem, reaching pandemic levels. For decades, dietary and behavioral approaches have failed to prevent this disease from expanding, and health authorities are challenged by the elevated prevalence of co-morbid conditions. Understanding how obesity-associated diseases develop from a basic science approach is recognized as an urgent task to face this growing problem. White adipose tissue (WAT) is an active endocrine organ, with a crucial influence on whole-body homeostasis. WAT dysfunction plays a key role linking obesity with its associated diseases such as type 2 diabetes mellitus, cardiovascular disease, and some cancers. Among the regulators of WAT physiology, the calcium-sensing receptor (CaSR) has arisen as a potential mediator of WAT dysfunction. Expression of the receptor has been described in human preadipocytes, adipocytes, and the human adipose cell lines LS14 and SW872. The evidence suggests that CaSR activation in the visceral (i.e., unhealthy) WAT is associated with an increased proliferation of adipose progenitor cells and elevated adipocyte differentiation. In addition, exposure of adipose cells to CaSR activators in vitro elevates proinflammatory cytokine expression and secretion. An increased proinflammatory environment in WAT plays a key role in the development of WAT dysfunction that leads to peripheral organ fat deposition and insulin resistance, among other consequences. We propose that CaSR may be one relevant therapeutic target in the struggle to confront the health consequences of the current worldwide obesity pandemic.

  15. Diabetes Stimulates Osteoclastogenesis by Acidosis-Induced Activation of Transient Receptor Potential Cation Channels

    PubMed Central

    Reni, Carlotta; Mangialardi, Giuseppe; Meloni, Marco; Madeddu, Paolo

    2016-01-01

    Patients with type 1 diabetes have lower bone mineral density and higher risk of fractures. The role of osteoblasts in diabetes-related osteoporosis is well acknowledged whereas the role of osteoclasts (OCLs) is still unclear. We hypothesize that OCLs participate in pathological bone remodeling. We conducted studies in animals (streptozotocin-induced type 1 diabetic mice) and cellular models to investigate canonical and non-canonical mechanisms underlying excessive OCL activation. Diabetic mice show an increased number of active OCLs. In vitro studies demonstrate the involvement of acidosis in OCL activation and the implication of transient receptor potential cation channel subfamily V member 1 (TRPV1). In vivo studies confirm the establishment of local acidosis in the diabetic bone marrow (BM) as well as the ineffectiveness of insulin in correcting the pH variation and osteoclast activation. Conversely, treatment with TRPV1 receptor antagonists re-establishes a physiological OCL availability. These data suggest that diabetes causes local acidosis in the BM that in turn increases osteoclast activation through the modulation of TRPV1. The use of clinically available TRPV1 antagonists may provide a new means to combat bone problems associated with diabetes. PMID:27468810

  16. Involvement of Transient Receptor Potential Vanilloid (TRPV) 4 in mouse sperm thermotaxis

    PubMed Central

    HAMANO, Koh-ichi; KAWANISHI, Tae; MIZUNO, Atsuko; SUZUKI, Makoto; TAKAGI, Yuji

    2016-01-01

    Transient Receptor Potential Vanilloid (TRPV) 4 is one of the temperature-sensitive ion channels involved in temperature receptors, and it is known to be activated from 35 to 40ºC. Here we analyzed sperm motility function of Trpv4 knockout (KO) mouse in temperature-gradient conditions to elucidate the thermotaxis of mouse sperm and the involvement of TRPV4 in thermotaxis. The sperm were introduced at the vertical column end of a T-shaped chamber filled with medium in a plastic dish, and we measured the number of sperm that arrived at both ends of the wide column where we had established a temperature gradient of approx. 2ºC, and we evaluated the sperm’s thermotaxis. Large numbers of wild-type (WT) mouse sperm migrated into the high level of the temperature gradient that was set in the wide column, and thermotaxis was confirmed. The ratio of migrated sperm at the high temperature level of the T-shaped chamber was decreased in the KO sperm and Ruthenium red (a TRPV antagonist) treated sperm compared with the WT sperm. The thermotaxis of the mouse sperm was confirmed, and the involvement of TRPV4 in this thermotaxis was suggested. PMID:27180924

  17. CCK1 receptor antagonist, dexloxiglumide: effects on human isolated gallbladder. Potential clinical applications.

    PubMed

    Maselli, M A; Mennuni, L

    2003-09-01

    Cholecystokinin is the main hormonal regulator of gallbladder motility. Dexloxiglumide, the active enantiomer of loxiglumide, interacts competitively with CCK1 receptors as determined in preclinical studies, such as specific radioligand binding assays or functional studies on isolated guinea pig gallbladder, where it inhibited smooth muscle cell contractions induced by cholecystokinin-octapeptide (CCK-8), the most prominent active forms of cholecystokinin. Dexloxiglumide has a potent antagonistic effect, of a competitive nature, on human gallbladder cholecystokinin type 1 receptors. In isolated human gallbladder, dexloxiglumide produced a concentration-dependent rightward shift of the cholecystokinin-octapeptide curve, without affecting its maximal response. Gallbladder motility was evaluated in clinical studies. Dexloxiglumide, orally administered to healthy volunteers at putative therapeutic doses, did not interfere with post-prandial gallbladder kinetics, despite an increase of fasting gallbladder volume. At present, dexloxiglumide is in an advanced stage of clinical research in gastroenterology. Overall, clinical observations suggest that dexloxiglumide may become an effective treatment in several gastrointestinal disorders. Moreover, the beneficial effects can be obtained without increasing the risk of gallstones formation, a potential hazard subsequent to the inhibition of gallbladder contractions and the resulting bile stasis. The potent and selective antagonist dexloxiglumide may offer a possible therapeutic tool for use not only in functional gastrointestinal disorders, such as irritable bowel syndrome, constipation, gastroesophageal reflux disease and functional dyspepsia, but also in other pathologies, such as biliary colics, pancreatic diseases and gastrointestinal tumors. PMID:16484960

  18. The distribution of transient receptor potential melastatin-8 in the rat soft palate, epiglottis, and pharynx.

    PubMed

    Sato, Tadasu; Fujita, Masatoshi; Kano, Mitsuhiro; Hosokawa, Hiroshi; Kondo, Teruyoshi; Suzuki, Toshihiko; Kasahara, Eriko; Shoji, Noriaki; Sasano, Takashi; Ichikawa, Hiroyuki

    2013-03-01

    Immunohistochemistry for transient receptor potential melastatin-8 (TRPM8), the cold and menthol receptor, was performed on the rat soft palate, epiglottis and pharynx. TRPM8-immunoreactive (IR) nerve fibers were located beneath the mucous epithelium, and occasionally penetrated the epithelium. These nerve fibers were abundant in the posterior portion of the soft palate and at the border region of naso-oral and laryngeal parts of the pharynx. The epiglottis was free from such nerve fibers. The double immunofluorescence method demonstrated that TRPM8-IR nerve fibers in the pharynx and soft palate were mostly devoid of calcitonin gene-related peptide-immunoreactivity (CGRP-IR). The retrograde tracing method also demonstrated that 30.1 and 8.7 % of sensory neurons in the jugular and petrosal ganglia innervating the pharynx contained TRPM8-IR, respectively. Among these neurons, the co-expression of TRPM8 and CGRP-IR was very rare. In the nodose ganglion, however, pharyngeal neurons were devoid of TRPM8-IR. Taste bud-like structures in the soft palate and pharynx contained 4-9 TRPM8-IR cells. In the epiglottis, the mucous epithelium on the laryngeal side had numerous TRPM8-IR cells. The present study suggests that TRPM8 can respond to cold stimulation when food and drinks pass through oral and pharyngeal cavities.

  19. A low-molecular-weight antagonist for the human thyrotropin receptor with therapeutic potential for hyperthyroidism.

    PubMed

    Neumann, Susanne; Kleinau, Gunnar; Costanzi, Stefano; Moore, Susanna; Jiang, Jian-kang; Raaka, Bruce M; Thomas, Craig J; Krause, Gerd; Gershengorn, Marvin C

    2008-12-01

    Low-molecular-weight (LMW) antagonists for TSH receptor (TSHR) may have therapeutic potential as orally active drugs to block stimulating antibodies (TsAbs) in Graves' hyperthyroidism. We describe an approach to identify LMW ligands for TSHR based on Org41841, a LMW partial agonist for the LH/choriogonadotropin receptor and TSHR. We used molecular modeling and functional experiments to guide the chemical modification of Org41841. We identified an antagonist (NIDDK/CEB-52) that selectively inhibits activation of TSHR by both TSH and TsAbs. Whereas initially characterized in cultured cells overexpressing TSHRs, the antagonist was also active under more physiologically relevant conditions in primary cultures of human thyrocytes expressing endogenous TSHRs in which it inhibited TSH- and TsAb-induced up-regulation of mRNA transcripts for thyroperoxidase. Our results establish this LMW compound as a lead for the development of higher potency antagonists and serve as proof of principle that LMW ligands that target TSHR could serve as drugs in patients with Graves' disease.

  20. Involvement of Transient Receptor Potential Vanilloid (TRPV) 4 in mouse sperm thermotaxis.

    PubMed

    Hamano, Koh-Ichi; Kawanishi, Tae; Mizuno, Atsuko; Suzuki, Makoto; Takagi, Yuji

    2016-08-25

    Transient Receptor Potential Vanilloid (TRPV) 4 is one of the temperature-sensitive ion channels involved in temperature receptors, and it is known to be activated from 35 to 40ºC. Here we analyzed sperm motility function of Trpv4 knockout (KO) mouse in temperature-gradient conditions to elucidate the thermotaxis of mouse sperm and the involvement of TRPV4 in thermotaxis. The sperm were introduced at the vertical column end of a T-shaped chamber filled with medium in a plastic dish, and we measured the number of sperm that arrived at both ends of the wide column where we had established a temperature gradient of approx. 2ºC, and we evaluated the sperm's thermotaxis. Large numbers of wild-type (WT) mouse sperm migrated into the high level of the temperature gradient that was set in the wide column, and thermotaxis was confirmed. The ratio of migrated sperm at the high temperature level of the T-shaped chamber was decreased in the KO sperm and Ruthenium red (a TRPV antagonist) treated sperm compared with the WT sperm. The thermotaxis of the mouse sperm was confirmed, and the involvement of TRPV4 in this thermotaxis was suggested. PMID:27180924

  1. Acid potentiation of the capsaicin receptor determined by a key extracellular site.

    PubMed

    Jordt, S E; Tominaga, M; Julius, D

    2000-07-01

    The capsaicin (vanilloid) receptor, VR1, is a sensory neuron-specific ion channel that serves as a polymodal detector of pain-producing chemical and physical stimuli. The response of VR1 to capsaicin or noxious heat is dynamically potentiated by extracellular protons within a pH range encountered during tissue acidosis, such as that associated with arthritis, infarction, tumor growth, and other forms of injury. A molecular determinant for this important physiological activity was localized to an extracellular Glu residue (E600) in the region linking the fifth transmembrane domain with the putative pore-forming region of the channel. We suggest that this residue serves as a key regulatory site of the receptor by setting sensitivity to other noxious stimuli in response to changes in extracellular proton concentration. We also demonstrate that protons, vanilloids, and heat promote channel opening through distinct pathways, because mutations at a second site (E648) selectively abrogate proton-evoked channel activation without diminishing responses to other noxious stimuli. Our findings provide molecular evidence for stimulus-specific steps in VR1 activation and offer strategies for the development of novel analgesic agents. PMID:10859346

  2. Pre-clinical studies in cough research: role of Transient Receptor Potential (TRP) channels.

    PubMed

    Grace, Megan S; Dubuis, Eric; Birrell, Mark A; Belvisi, Maria G

    2013-10-01

    Cough is a protective reflex and defence mechanism in healthy individuals, which helps clear excessive secretions and foreign material from the lungs. Cough often presents as the first and most persistent symptom of many respiratory diseases and some non-respiratory disorders, but can also be idiopathic, and is a common respiratory complaint for which medical attention is sought. Chronic cough of various aetiologies is a regular presentation to specialist respiratory clinics, and is reported as a troublesome symptom by a significant proportion of the population. Despite this, the treatment options for cough are limited. The lack of effective anti-tussives likely stems from our incomplete understanding of how the tussive reflex is mediated. However, research over the last decade has begun to shed some light on the mechanisms which provoke cough, and may ultimately provide us with better anti-tussive therapies. This review will focus on the in vitro and in vivo models that are currently used to further our understanding of the sensory innervation of the respiratory tract, and how these nerves are involved in controlling the cough response. Central to this are the Transient Receptor Potential (TRP) ion channels, a family of polymodal receptors that can be activated by such diverse stimuli as chemicals, temperature, osmotic stress, and mechanical perturbation. These ion channels are thought to be molecular pain integrators and targets for novel analgesic agents for the treatment of various pain disorders but some are also being developed as anti-tussives. PMID:23474212

  3. Acid-sensing ion channels and transient-receptor potential ion channels in zebrafish taste buds.

    PubMed

    Levanti, M; Randazzo, B; Viña, E; Montalbano, G; Garcia-Suarez, O; Germanà, A; Vega, J A; Abbate, F

    2016-09-01

    Sensory information from the environment is required for life and survival, and it is detected by specialized cells which together make up the sensory system. The fish sensory system includes specialized organs that are able to detect mechanical and chemical stimuli. In particular, taste buds are small organs located on the tongue in terrestrial vertebrates that function in the perception of taste. In fish, taste buds occur on the lips, the flanks, and the caudal (tail) fins of some species and on the barbels of others. In fish taste receptor cells, different classes of ion channels have been detected which, like in mammals, presumably participate in the detection and/or transduction of chemical gustatory signals. However, since some of these ion channels are involved in the detection of additional sensory modalities, it can be hypothesized that taste cells sense stimuli other than those specific for taste. This mini-review summarizes current knowledge on the presence of transient-receptor potential (TRP) and acid-sensing (ASIC) ion channels in the taste buds of teleosts, especially adult zebrafish. Up to now ASIC4, TRPC2, TRPA1, TRPV1 and TRPV4 ion channels have been found in the sensory cells, while ASIC2 was detected in the nerves supplying the taste buds. PMID:27513962

  4. Plasmin potentiates synaptic N-methyl-D-aspartate receptor function in hippocampal neurons through activation of protease-activated receptor-1.

    PubMed

    Mannaioni, Guido; Orr, Anna G; Hamill, Cecily E; Yuan, Hongjie; Pedone, Katherine H; McCoy, Kelly L; Berlinguer Palmini, Rolando; Junge, Candice E; Lee, C Justin; Yepes, Manuel; Hepler, John R; Traynelis, Stephen F

    2008-07-18

    Protease-activated receptor-1 (PAR1) is activated by a number of serine proteases, including plasmin. Both PAR1 and plasminogen, the precursor of plasmin, are expressed in the central nervous system. In this study we examined the effects of plasmin in astrocyte and neuronal cultures as well as in hippocampal slices. We find that plasmin evokes an increase in both phosphoinositide hydrolysis (EC(50) 64 nm) and Fura-2/AM fluorescence (195 +/- 6.7% above base line, EC(50) 65 nm) in cortical cultured murine astrocytes. Plasmin also activates extracellular signal-regulated kinase (ERK1/2) within cultured astrocytes. The plasmin-induced rise in intracellular Ca(2+) concentration ([Ca(2+)](i)) and the increase in phospho-ERK1/2 levels were diminished in PAR1(-/-) astrocytes and were blocked by 1 microm BMS-200261, a selective PAR1 antagonist. However, plasmin had no detectable effect on ERK1/2 or [Ca(2+)](i) signaling in primary cultured hippocampal neurons or in CA1 pyramidal cells in hippocampal slices. Plasmin (100-200 nm) application potentiated the N-methyl-D-aspartate (NMDA) receptor-dependent component of miniature excitatory postsynaptic currents recorded from CA1 pyramidal neurons but had no effect on alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate- or gamma-aminobutyric acid receptor-mediated synaptic currents. Plasmin also increased NMDA-induced whole cell receptor currents recorded from CA1 pyramidal cells (2.5 +/- 0.3-fold potentiation over control). This effect was blocked by BMS-200261 (1 microm; 1.02 +/- 0.09-fold potentiation over control). These data suggest that plasmin may serve as an endogenous PAR1 activator that can increase [Ca(2+)](i) in astrocytes and potentiate NMDA receptor synaptic currents in CA1 pyramidal neurons.

  5. Transient receptor potential (TRP) channels in the airway: role in airway disease

    PubMed Central

    Grace, M S; Baxter, M; Dubuis, E; Birrell, M A; Belvisi, M G

    2014-01-01

    Over the last few decades, there has been an explosion of scientific publications reporting the many and varied roles of transient receptor potential (TRP) ion channels in physiological and pathological systems throughout the body. The aim of this review is to summarize the existing literature on the role of TRP channels in the lungs and discuss what is known about their function under normal and diseased conditions. The review will focus mainly on the pathogenesis and symptoms of asthma and chronic obstructive pulmonary disease and the role of four members of the TRP family: TRPA1, TRPV1, TRPV4 and TRPM8. We hope that the article will help the reader understand the role of TRP channels in the normal airway and how their function may be changed in the context of respiratory disease. PMID:24286227

  6. Changes in Membrane Receptors and Ion Channels as Potential Biomarkers for Osteoarthritis

    PubMed Central

    Lewis, Rebecca; Barrett-Jolley, Richard

    2015-01-01

    Osteoarthritis (OA), a degenerative joint condition, is currently difficult to detect early enough for any of the current treatment options to be completely successful. Early diagnosis of this disease could increase the numbers of patients who are able to slow its progression. There are now several diseases where membrane protein biomarkers are used for early diagnosis. The numbers of proteins in the membrane is vast and so it is a rich source of potential biomarkers for OA but we need more knowledge of these before they can be considered practical biomarkers. How are they best measured and are they selective to OA or even certain types of OA? The first step in this process is to identify membrane proteins that change in OA. Here, we summarize several ion channels and receptors that change in OA models and/or OA patients, and may thus be considered candidates as novel membrane biomarkers of OA. PMID:26648874

  7. Functionalized Ergot-alkaloids as potential dopamine D3 receptor agonists for treatment of schizophrenia

    NASA Astrophysics Data System (ADS)

    Ivanova, Bojidarka; Spiteller, Michael

    2012-12-01

    The relationship between the molecular structure and physical properties of functionalized naturally occurred Ergot-alkaloids as potential dopamine D3 receptor agonists is presented. The molecular modeling of the ergoline-skeleton is based on the comprehensive theoretical study of the binding affinity of the isolated chemicals towards the active sites of the D3 sub-type receptor (D3R) loops. The studied proton accepting ability under physiological conditions allows classifying four types of monocationics, characterizing with the different binding modes to D3R involving selected amino acid residues to the active sites. These results marked the pharmaceutical potential and clinical usage of the reported compounds as antipsychotic drugs for Schizophrenia treatment, since they allowed evaluating the highlights of the different hypothesizes of the biochemical causes the illness. The applied complex approach for theoretical and experimental elucidation, including quantum chemistry method, electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) mass spectrometric (MS) methods, nuclear magnetic resonance and vibrational IR and Raman spectroscopy on the isolated fifteen novel derivatives (1)-(15) and their different protonated forms (1a)-(15a) evidenced a strong dependence of molecular conformation, physical properties and binding affinity. Thus, the semi-synthetic functionalization of the naturally occurred products (NPs), provided significant possibilities to further molecular drugs-design and development of novel derivatives with wanted biological function, using the established profile of selected classes/families of NPs. The work described chiefly the non-linear (NL) approach for the interpretation of the mass chromatograms on the performed hybrid high performance liquid chromatography (HPLC) tandem MS/MS and MS/MS/MS experiments, discussing the merits and great diversity of instrumentation flexibility, thus achieving fundamental

  8. Transient Receptor Potential Channels in Microglia: Roles in Physiology and Disease.

    PubMed

    Echeverry, Santiago; Rodriguez, María Juliana; Torres, Yolima P

    2016-10-01

    Microglia modulate the nervous system cellular environment and induce neuroprotective and neurotoxic effects. Various molecules are involved in these processes, including families of ion channels expressed in microglial cells, such as transient receptor potential (TRP) channels. TRP channels comprise a family of non-selective cation channels that can be activated by mechanical, thermal, and chemical stimuli, and which contribute to the regulation of intracellular calcium concentrations. TRP channels have been shown to be involved in cellular processes such as osmotic regulation, cytokine production, proliferation, activation, cell death, and oxidative stress responses. Given the significance of these processes in microglial activity, studies of TRP channels in microglia have focused on determining their roles in both neuroprotective and neurotoxic processes. TRP channel activity has been proposed to play an important function in neurodegenerative diseases, ischemia, inflammatory responses, and neuropathic pain. Modulation of TRP channel activity may thus be considered as a potential therapeutic strategy for the treatment of various diseases associated with alterations of the central nervous system (CNS). In this review, we describe the expression of different subfamilies of TRP channels in microglia, focusing on their physiological and pathophysiological roles, and consider their potential use as therapeutic targets in CNS diseases. PMID:27260222

  9. Transient Receptor Potential Channels in Microglia: Roles in Physiology and Disease.

    PubMed

    Echeverry, Santiago; Rodriguez, María Juliana; Torres, Yolima P

    2016-10-01

    Microglia modulate the nervous system cellular environment and induce neuroprotective and neurotoxic effects. Various molecules are involved in these processes, including families of ion channels expressed in microglial cells, such as transient receptor potential (TRP) channels. TRP channels comprise a family of non-selective cation channels that can be activated by mechanical, thermal, and chemical stimuli, and which contribute to the regulation of intracellular calcium concentrations. TRP channels have been shown to be involved in cellular processes such as osmotic regulation, cytokine production, proliferation, activation, cell death, and oxidative stress responses. Given the significance of these processes in microglial activity, studies of TRP channels in microglia have focused on determining their roles in both neuroprotective and neurotoxic processes. TRP channel activity has been proposed to play an important function in neurodegenerative diseases, ischemia, inflammatory responses, and neuropathic pain. Modulation of TRP channel activity may thus be considered as a potential therapeutic strategy for the treatment of various diseases associated with alterations of the central nervous system (CNS). In this review, we describe the expression of different subfamilies of TRP channels in microglia, focusing on their physiological and pathophysiological roles, and consider their potential use as therapeutic targets in CNS diseases.

  10. Interaction Between Helminths and Toll-Like Receptors: Possibilities and Potentials for Asthma Therapy.

    PubMed

    Zakeri, Amin; Borji, Hassan; Haghparast, Alireza

    2016-05-01

    Toll-like receptors (TLRs) are essential components of the innate immune system. They play an important role in the pathogenesis of allergic diseases, especially asthma. Since TLRs significantly orchestrate innate and adaptive immune response, their manipulation has widely been considered as a potential approach to control asthma symptoms. It is well established that helminths have immunoregulatory effects on host immune responses, especially innate immunity. They release bioactive molecules such as excretory-secretory (ES) products manipulating TLRs expression and signaling. Thus, given the promising results derived from preclinical studies, harnessing helminth-derived molecules affecting TLRs can be considered as a potential biological therapy for allergic diseases. Prospectively, the data that are available at present suggest that, in the near future, it is possible that helminth antigens will offer new therapeutic strategies and druggable targets for fighting allergic diseases. This review describes the interactions between helminths and TLRs and discusses the potential possibilities for asthma therapy. In this opinion paper, the authors aimed to review the updated literatures on the interplay between helminths, TLRs, and asthma with a view to proposing helminth-based asthma therapy. PMID:27120222

  11. Long-term potentiation and the role of N-methyl-D-aspartate receptors.

    PubMed

    Volianskis, Arturas; France, Grace; Jensen, Morten S; Bortolotto, Zuner A; Jane, David E; Collingridge, Graham L

    2015-09-24

    N-methyl-D-aspartate receptors (NMDARs) are known for their role in the induction of long-term potentiation (LTP). Here we start by reviewing the early evidence for their role in LTP at CA1 synapses in the hippocampus. We then discuss more recent evidence that NMDAR dependent synaptic plasticity at these synapses can be separated into mechanistically distinct components. An initial phase of the synaptic potentiation, which is generally termed short-term potentiation (STP), decays in an activity-dependent manner and comprises two components that differ in their kinetics and NMDAR subtype dependence. The faster component involves activation of GluN2A and GluN2B subunits whereas the slower component involves activation of GluN2B and GluN2D subunits. The stable phase of potentiation, commonly referred to as LTP, requires activation of primarily triheteromeric NMDARs containing both GluN2A and GluN2B subunits. In new work, we compare STP with a rebound potentiation (RP) that is induced by NMDA application and conclude that they are different phenomena. We also report that NMDAR dependent long-term depression (NMDAR-LTD) is sensitive to a glycine site NMDAR antagonist. We conclude that NMDARs are not synonymous for either LTP or memory. Whilst important for the induction of LTP at many synapses in the CNS, not all forms of LTP require the activation of NMDARs. Furthermore, NMDARs mediate the induction of other forms of synaptic plasticity and are important for synaptic transmission. It is, therefore, not possible to equate NMDARs with LTP though they are intimately linked. This article is part of a Special Issue entitled SI: Brain and Memory.

  12. Long-term potentiation and the role of N-methyl-d-aspartate receptors

    PubMed Central

    Volianskis, Arturas; France, Grace; Jensen, Morten S.; Bortolotto, Zuner A.; Jane, David E.; Collingridge, Graham L.

    2015-01-01

    N-methyl-d-aspartate receptors (NMDARs) are known for their role in the induction of long-term potentiation (LTP). Here we start by reviewing the early evidence for their role in LTP at CA1 synapses in the hippocampus. We then discuss more recent evidence that NMDAR dependent synaptic plasticity at these synapses can be separated into mechanistically distinct components. An initial phase of the synaptic potentiation, which is generally termed short-term potentiation (STP), decays in an activity-dependent manner and comprises two components that differ in their kinetics and NMDAR subtype dependence. The faster component involves activation of GluN2A and GluN2B subunits whereas the slower component involves activation of GluN2B and GluN2D subunits. The stable phase of potentiation, commonly referred to as LTP, requires activation of primarily triheteromeric NMDARs containing both GluN2A and GluN2B subunits. In new work, we compare STP with a rebound potentiation (RP) that is induced by NMDA application and conclude that they are different phenomena. We also report that NMDAR dependent long-term depression (NMDAR-LTD) is sensitive to a glycine site NMDAR antagonist. We conclude that NMDARs are not synonymous for either LTP or memory. Whilst important for the induction of LTP at many synapses in the CNS, not all forms of LTP require the activation of NMDARs. Furthermore, NMDARs mediate the induction of other forms of synaptic plasticity and are important for synaptic transmission. It is, therefore, not possible to equate NMDARs with LTP though they are intimately linked. This article is part of a Special Issue entitled SI: Brain and Memory. PMID:25619552

  13. Antagonism of Lateral Amygdala Alpha1-Adrenergic Receptors Facilitates Fear Conditioning and Long-Term Potentiation

    ERIC Educational Resources Information Center

    Lazzaro, Stephanie C.; Hou, Mian; Cunha, Catarina; LeDoux, Joseph E.; Cain, Christopher K.

    2010-01-01

    Norepinephrine receptors have been studied in emotion, memory, and attention. However, the role of alpha1-adrenergic receptors in fear conditioning, a major model of emotional learning, is poorly understood. We examined the effect of terazosin, an alpha1-adrenergic receptor antagonist, on cued fear conditioning. Systemic or intra-lateral amygdala…

  14. Potentiation of the actions of acetylcholine, epibatidine, and nicotine by methyllycaconitine at fetal muscle-type nicotinic acetylcholine receptors.

    PubMed

    Green, Benedict T; Welch, Kevin D; Cook, Daniel; Gardner, Dale R

    2011-07-15

    Methyllycaconitine (MLA) is a norditerpenoid alkaloid found in high abundance in toxic Delphinium (larkspur) species. It is a potent and selective antagonist of α(7)-nicotinic acetylcholine receptors, but has not been well investigated for activity aside from receptor antagonism. The aim of this study was to investigate the effects of MLA alone and in combination with acetylcholine, epibatidine, nicotine, and neostigmine for actions other than receptor antagonism in TE-671 cells expressing (α(1))(2)β(1)γδ nicotinic acetylcholine receptors. Ligand activity was assessed through measurements of membrane potential changes in TE-671 cells using a fluorescent membrane potential-sensitive dye and normalized to the maximum response to epibatidine (10μM). MLA was ineffective in changing cell membrane potential in the absence of other receptor agonists. However at nanomolar concentrations, it acted as a co-agonist to potentiate TE-671 cell responses to acetylcholine, epibatidine, nicotine, and neostigmine. These results suggest that the poisoning of cattle by norditerpenoid alkaloids found in larkspur may be more complex than previously determined.

  15. Regulation of transient receptor potential channels of melastatin type 8 (TRPM8): effect of cAMP, cannabinoid CB(1) receptors and endovanilloids.

    PubMed

    De Petrocellis, Luciano; Starowicz, Katarzyna; Moriello, Aniello Schiano; Vivese, Marta; Orlando, Pierangelo; Di Marzo, Vincenzo

    2007-05-15

    The transient receptor potential channel of melastatin type 8 (TRPM8), which is gated by low (<25 degrees C) temperature and chemical compounds, is regulated by protein kinase C-mediated phosphorylation in a way opposite to that observed with the transient receptor potential channel of vanilloid type 1 (TRPV1), i.e. by being desensitized and not sensitized. As TRPV1 is sensitized also by protein kinase A (PKA)-mediated phosphorylation, we investigated the effect of two activators of the PKA pathway, 8-Br-cAMP and forskolin, on the activity of menthol and icilin at TRPM8 in HEK-293 cells stably overexpressing the channel (TRPM8-HEK-293 cells). We also studied the effect on TRPM8 of: (1) a series of compounds previously shown to activate or antagonize TRPV1, and (2) co-stimulation of transiently co-expressed cannabinoid CB(1) receptors. Both 8-Br-cAMP (100 microM) and forskolin (10 microM) right-shifted the dose-response curves for the TRPM8-mediated effect of icilin and menthol on intracellular Ca(2+). The inhibitory effects of 8-Br-cAMP and forskolin were attenuated by the selective PKA inhibitor Rp-cAMP-S. Stimulation of human CB(1) receptors transiently co-expressed in TRPM8-HEK-293 cells also inhibited TRPM8 response to icilin. Finally, some TRPV1 agonists and antagonists, but not iodinated antagonists, antagonized icilin- and much less so menthol-, induced TRPM8 activation. Importantly, the endovanilloids/endocannabinoids, anandamide and NADA, also antagonized TRPM8 at submicromolar concentrations. Although these findings need to be confirmed by experiments directly measuring TRPM8 activity in natively TRPM8-expressing cells, they support the notion that the same regulatory events have opposing actions on TRPM8 and TRPV1 receptors and identify anandamide and NADA as the first potential endogenous functional antagonists of TRPM8 channels.

  16. Neutrophil beta-adrenergic receptor responses are potentiated by acute exposure to phorbol ester without changes in receptor distribution or coupling

    SciTech Connect

    Kilfeather, S.A.; Stein, M.; O'Malley, K. )

    1991-01-01

    Exposure to the phorbol ester, phorbol 12-myristate, 13-acetate for 10 minutes enhanced cyclic AMP accumulation in human neutrophils under basal conditions and in response to the beta-adrenergic receptor agonist isoproterenol (ISO, 1{mu}M) and the adenylate cyclase activator forskolin (FSK, 10mM). Potentiation of responses to ISO by PMA was dose-dependent between 0.1 and 100nM PMA. The diacylglycerol analogue, 1-oleoyl-2-actylgylcerol (OAG) (50 {mu}M) also elevated beta-receptor responses, but 4beta-phorbol (100nM), lacking the capacity to activate PMA, was ineffective. Short-term exposure to the peptide n-formylmethionine leucyl-phenylalanine (FMLP, 1 {mu}M) also elevated neutrophil cyclic AMP accumulation. All potentiating effects of PMA on cyclic AMP production were inhibited by the protein kinase inhibitor 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H{sub 7}). PMA had no apparent effect on beta-receptor agonist-affinity, distribution between cell-surface and internalized compartments, or the capacity of ISO to induce beta-receptor internalization. Responses to FSK or ISO in terms of fold-stimulation of basal cyclic AMP accumulation int he presence of PMA were not elevated by PMA.

  17. A subunit-selective potentiator of NR2C- and NR2D-containing NMDA receptors

    PubMed Central

    Mullasseril, Praseeda; Hansen, Kasper B.; Vance, Katie M.; Ogden, Kevin K.; Yuan, Hongjie; Kurtkaya, Natalie L.; Santangelo, Rose; Orr, Anna G.; Le, Phuong; Vellano, Kimberly M.; Liotta, Dennis C.; Traynelis, Stephen F.

    2011-01-01

    NMDA receptors are tetrameric complexes of NR1 and NR2A-D subunits that mediate excitatory synaptic transmission and play a role in neurological disorders. We have identified a novel subunit-selective potentiator of NMDA receptors containing the NR2C or NR2D subunit, which could allow selective modification of circuit function in regions expressing NR2C/D subunits. The substituted tetrahydroisoquinoline CIQ enhances receptor responses two-fold with an EC50 of 3 μM by increasing channel opening frequency without altering mean open time or EC50 values for glutamate or glycine. The actions of CIQ depend on a single residue in the M1 region (NR2D Thr592) and the linker between the amino terminal domain and agonist binding domain. CIQ potentiates native NR2D-containing NMDA receptor currents from subthalamic neurons. Our identification of a subunit-selective NMDA receptor modulator reveals a new class of pharmacological tools with which to probe the role of NR2C- and NR2D-containing NMDA receptors in brain function and disease. PMID:20981015

  18. Alteration of the mu opioid receptor: Ca2+ channel signaling pathway in a subset of rat sensory neurons following chronic femoral artery occlusion.

    PubMed

    Hassan, Bassil; Kim, Joyce S; Farrag, Mohamed; Kaufman, Marc P; Ruiz-Velasco, Victor

    2014-12-15

    The exercise pressor reflex, a crucial component of the cardiovascular response under physiological and pathophysiological states, is activated via metabolic and mechanical mediators that originate from contracting muscles and stimulate group III and IV afferents. We reported previously that stimulation of mu opioid receptors (MOR), expressed in both afferents, led to a significant attenuation of the reflex in rats whose femoral arteries had been occluded for 72 h. The present study examined the effect of arterial occlusion on the signaling components involved in the opioid-mediated modulation of Ca(2+) channels in rat dorsal root ganglion neurons innervating the triceps surae muscles. We focused on neurons that were transfected with cDNA coding for enhanced green fluorescent protein whose expression is driven by the voltage-gated Na(+) channel 1.8 (Na(V)1.8) promoter region, a channel expressed primarily in nociceptive neurons. With the use of a small interference RNA approach, our results show that the pertussis toxin-sensitive Gα(i3) subunit couples MOR with Ca(2+) channels. We observed a significant leftward shift of the MOR agonist [D-Ala2-N-Me-Phe4-Glycol5]-enkephalin concentration-response relationship in neurons isolated from rats with occluded arteries compared with those that were perfused freely. Femoral occlusion did not affect Ca(2+) channel density or the fraction of the main Ca(2+) channel subtype. Furthermore, Western blotting analysis indicated that the leftward shift did not result from either increased Gα(i3) or MOR expression. Finally, all neurons from both groups exhibited an inward current following exposure of the transient potential receptor vanilloid 1 (TRPV1) agonist, 8-methyl-N-vanillyl-6-nonenamide. These findings suggest that sensory neurons mediating the exercise pressor reflex express Na(V)1.8 and TRPV1 channels, and femoral occlusion alters the MOR pharmacological profile. PMID:25231620

  19. Sex Differences in Kappa Opioid Receptor Function and Their Potential Impact on Addiction

    PubMed Central

    Chartoff, Elena H.; Mavrikaki, Maria

    2015-01-01

    Behavioral, biological, and social sequelae that lead to drug addiction differ between men and women. Our efforts to understand addiction on a mechanistic level must include studies in both males and females. Stress, anxiety, and depression are tightly linked to addiction, and whether they precede or result from compulsive drug use depends on many factors, including biological sex. The neuropeptide dynorphin (DYN), an endogenous ligand at kappa opioid receptors (KORs), is necessary for stress-induced aversive states and is upregulated in the brain after chronic exposure to drugs of abuse. KOR agonists produce signs of anxiety, fear, and depression in laboratory animals and humans, findings that have led to the hypothesis that drug withdrawal-induced DYN release is instrumental in negative reinforcement processes that drive addiction. However, these studies were almost exclusively conducted in males. Only recently is evidence available that there are sex differences in the effects of KOR activation on affective state. This review focuses on sex differences in DYN and KOR systems and how these might contribute to sex differences in addictive behavior. Much of what is known about how biological sex influences KOR systems is from research on pain systems. The basic molecular and genetic mechanisms that have been discovered to underlie sex differences in KOR function in pain systems may apply to sex differences in KOR function in reward systems. Our goals are to discuss the current state of knowledge on how biological sex contributes to KOR function in the context of pain, mood, and addiction and to explore potential mechanisms for sex differences in KOR function. We will highlight evidence that the function of DYN-KOR systems is influenced in a sex-dependent manner by: polymorphisms in the prodynorphin (pDYN) gene, genetic linkage with the melanocortin-1 receptor (MC1R), heterodimerization of KORs and mu opioid receptors (MORs), and gonadal hormones. Finally, we

  20. Sex Differences in Kappa Opioid Receptor Function and Their Potential Impact on Addiction.

    PubMed

    Chartoff, Elena H; Mavrikaki, Maria

    2015-01-01

    Behavioral, biological, and social sequelae that lead to drug addiction differ between men and women. Our efforts to understand addiction on a mechanistic level must include studies in both males and females. Stress, anxiety, and depression are tightly linked to addiction, and whether they precede or result from compulsive drug use depends on many factors, including biological sex. The neuropeptide dynorphin (DYN), an endogenous ligand at kappa opioid receptors (KORs), is necessary for stress-induced aversive states and is upregulated in the brain after chronic exposure to drugs of abuse. KOR agonists produce signs of anxiety, fear, and depression in laboratory animals and humans, findings that have led to the hypothesis that drug withdrawal-induced DYN release is instrumental in negative reinforcement processes that drive addiction. However, these studies were almost exclusively conducted in males. Only recently is evidence available that there are sex differences in the effects of KOR activation on affective state. This review focuses on sex differences in DYN and KOR systems and how these might contribute to sex differences in addictive behavior. Much of what is known about how biological sex influences KOR systems is from research on pain systems. The basic molecular and genetic mechanisms that have been discovered to underlie sex differences in KOR function in pain systems may apply to sex differences in KOR function in reward systems. Our goals are to discuss the current state of knowledge on how biological sex contributes to KOR function in the context of pain, mood, and addiction and to explore potential mechanisms for sex differences in KOR function. We will highlight evidence that the function of DYN-KOR systems is influenced in a sex-dependent manner by: polymorphisms in the prodynorphin (pDYN) gene, genetic linkage with the melanocortin-1 receptor (MC1R), heterodimerization of KORs and mu opioid receptors (MORs), and gonadal hormones. Finally, we

  1. Sex Differences in Kappa Opioid Receptor Function and Their Potential Impact on Addiction.

    PubMed

    Chartoff, Elena H; Mavrikaki, Maria

    2015-01-01

    Behavioral, biological, and social sequelae that lead to drug addiction differ between men and women. Our efforts to understand addiction on a mechanistic level must include studies in both males and females. Stress, anxiety, and depression are tightly linked to addiction, and whether they precede or result from compulsive drug use depends on many factors, including biological sex. The neuropeptide dynorphin (DYN), an endogenous ligand at kappa opioid receptors (KORs), is necessary for stress-induced aversive states and is upregulated in the brain after chronic exposure to drugs of abuse. KOR agonists produce signs of anxiety, fear, and depression in laboratory animals and humans, findings that have led to the hypothesis that drug withdrawal-induced DYN release is instrumental in negative reinforcement processes that drive addiction. However, these studies were almost exclusively conducted in males. Only recently is evidence available that there are sex differences in the effects of KOR activation on affective state. This review focuses on sex differences in DYN and KOR systems and how these might contribute to sex differences in addictive behavior. Much of what is known about how biological sex influences KOR systems is from research on pain systems. The basic molecular and genetic mechanisms that have been discovered to underlie sex differences in KOR function in pain systems may apply to sex differences in KOR function in reward systems. Our goals are to discuss the current state of knowledge on how biological sex contributes to KOR function in the context of pain, mood, and addiction and to explore potential mechanisms for sex differences in KOR function. We will highlight evidence that the function of DYN-KOR systems is influenced in a sex-dependent manner by: polymorphisms in the prodynorphin (pDYN) gene, genetic linkage with the melanocortin-1 receptor (MC1R), heterodimerization of KORs and mu opioid receptors (MORs), and gonadal hormones. Finally, we

  2. Transient receptor potential melastatin 4 channel contributes to migration of androgen-insensitive prostate cancer cells

    PubMed Central

    Kilch, Tatiana; Jochum, Marcus Martin; Urban, Sabine Katharina; Jung, Volker; Stöckle, Michael; Rother, Karen; Greiner, Markus; Peinelt, Christine

    2015-01-01

    Impaired Ca2+ signaling in prostate cancer contributes to several cancer hallmarks, such as enhanced proliferation and migration and a decreased ability to induce apoptosis. Na+ influx via transient receptor potential melastatin 4 channel (TRPM4) can reduce store-operated Ca2+ entry (SOCE) by decreasing the driving force for Ca2+. In patients with prostate cancer, gene expression of TRPM4 is elevated. Recently, TRPM4 was identified as a cancer driver gene in androgen-insensitive prostate cancer. We investigated TRPM4 protein expression in cancer tissue samples from 20 patients with prostate cancer. We found elevated TRPM4 protein levels in prostatic intraepithelial neoplasia (PIN) and prostate cancer tissue compared to healthy tissue. In primary human prostate epithelial cells (hPEC) from healthy tissue and in the androgen-insensitive prostate cancer cell lines DU145 and PC3, TRPM4 mediated large Na+ currents. We demonstrated significantly increased SOCE after siRNA targeting of TRPM4 in hPEC and DU145 cells. In addition, knockdown of TRPM4 reduced migration but not proliferation of DU145 and PC3 cells. Taken together, our data identify TRPM4 as a regulator of SOCE in hPEC and DU145 cells, demonstrate a role for TRPM4 in cancer cell migration and suggest that TRPM4 is a promising potential therapeutic target. PMID:26496025

  3. Functional characterization of transient receptor potential channels in mouse urothelial cells.

    PubMed

    Everaerts, Wouter; Vriens, Joris; Owsianik, Grzegorz; Appendino, Giovanni; Voets, Thomas; De Ridder, Dirk; Nilius, Bernd

    2010-03-01

    The bladder urothelium is currently believed to be a sensory structure, contributing to mechano- and chemosensation in the bladder. Transient receptor potential (TRP) cation channels act as polymodal sensors and may underlie some of the receptive properties of urothelial cells. However, the exact TRP channel expression profile of urothelial cells is unclear. In this study, we have performed a systematic analysis of the molecular and functional expression of various TRP channels in mouse urothelium. Urothelial cells from control and trpv4-/- mice were isolated, cultured (12-48 h), and used for quantitative real-time PCR, immunocytochemistry, calcium imaging, and whole cell patch-clamp experiments. At the mRNA level, TRPV4, TRPV2, and TRPM7 were the most abundantly expressed TRP genes. Immunohistochemistry showed a clear expression of TRPV4 in the plasma membrane, whereas TRPV2 was more prominent in the cytoplasm. TRPM7 was detected in the plasma membrane as well as cytoplasmic vesicles. Calcium imaging and patch-clamp experiments using TRP channel agonists and antagonists provided evidence for the functional expression of TRPV4, TRPV2, and TRPM7 but not of TRPA1, TRPV1, and TRPM8. In conclusion, we have demonstrated functional expression of TRPV4, TRPV2, and TRPM7 in mouse urothelial cells. These channels may contribute to the (mechano)sensory function of the urothelial layer and represent potential targets for the treatment of bladder dysfunction. PMID:20015940

  4. Novel role for the transient receptor potential channel TRPM2 in prostate cancer cell proliferation

    PubMed Central

    Zeng, X; Sikka, S C; Huang, L; Sun, C; Xu, C; Jia, D; Abdel-Mageed, A B; Pottle, J E; Taylor, J T; Li, M

    2009-01-01

    We have identified a novel function for a member of the transient receptor potential (TRP) protein super-family, TRPM2, in prostate cancer cell proliferation. TRPM2 encodes a non-selective cation-permeable ion channel. We found that selectively knocking down TRPM2 with the small interfering RNA technique inhibited the growth of prostate cancer cells but not of non-cancerous cells. The subcellular localization of this protein is also remarkably different between cancerous and non-cancerous cells. In BPH-1 (benign), TRPM2 protein is homogenously located near the plasma membrane and in the cytoplasm, whereas in the cancerous cells (PC-3 and DU-145), a significant amount of the TRPM2 protein is located in the nuclei in a clustered pattern. Furthermore, we have found that TRPM2 inhibited nuclear ADP-ribosylation in prostate cancer cells. However, TRPM2 knockdown-induced inhibition of proliferation is independent of the activity of poly(ADP-ribose) polymerases. We conclude that TRPM2 is essential for prostate cancer cell proliferation and may be a potential target for the selective treatment of prostate cancer. PMID:20029400

  5. Modulation of Adult Mesenchymal Stem Cells Activity by Toll-Like Receptors: Implications on Therapeutic Potential

    PubMed Central

    DelaRosa, Olga; Lombardo, Eleuterio

    2010-01-01

    Mesenchymal stem cells (MSCs) are of special interest as therapeutic agents in the settings of both chronic inflammatory and autoimmune diseases. Toll-like receptors (TLR) ligands have been linked with the perpetuation of inflammation in a number of chronic inflammatory diseases due to the permanent exposure of the immune system to TLR-specific stimuli. Therefore, MSCs employed in therapy can be potentially exposed to TLR ligands, which may modulate MSC therapeutic potential in vivo. Recent results demonstrate that MSCs are activated by TLR ligands leading to modulation of the differentiation, migration, proliferation, survival, and immunosuppression capacities. However inconsistent results among authors have been reported suggesting that the source of MSCs, TLR stimuli employed or culture conditions play a role. Notably, activation by TLR ligands has not been reported to modulate the “immunoprivileged” phenotype of MSCs which is of special relevance regarding the use of allogeneic MSC-based therapies. In this review, we discuss the available data on the modulation of MSCs activity through TLR signalling. PMID:20628526

  6. Depletion of serotonin in the basolateral amygdala elevates glutamate receptors and facilitates fear-potentiated startle

    PubMed Central

    Tran, L; Lasher, B K; Young, K A; Keele, N B

    2013-01-01

    Our previous experiments demonstrated that systemic depletion of serotonin (5-hydroxytryptamine, 5-HT), similar to levels reported in patients with emotional disorders, enhanced glutamateric activity in the lateral nucleus of the amygdala (LA) and potentiated fear behaviors. However, the effects of isolated depletion of 5-HT in the LA, and the molecular mechanisms underlying enhanced glutamatergic activity are unknown. In the present study, we tested the hypothesis that depletion of 5-HT in the LA induces increased fear behavior, and concomitantly enhances glutamate receptor (GluR) expression. Bilateral infusions of 5,7-dihydroxytryptamine (4 μg per side) into the LA produced a regional reduction of serotonergic fibers, resulting in decreased 5-HT concentrations. The induction of low 5-HT in the LA elevated fear-potentiated startle, with a parallel increase in GluR1 mRNA and GluR1 protein expression. These findings suggest that low 5-HT concentrations in the LA may facilitate fear behavior through enhanced GluR-mediated mechanisms. Moreover, our data support a relationship between 5-HT and glutamate in psychopathologies. PMID:24002084

  7. Structural and Functional Interactions between Transient Receptor Potential Vanilloid Subfamily 1 and Botulinum Neurotoxin Serotype A

    PubMed Central

    2016-01-01

    Background Botulinum neurotoxins are produced by Clostridium botulinum bacteria. There are eight serologically distinct botulinum neurotoxin isoforms (serotypes A–H). Currently, botulinum neurotoxin serotype A (BoNT⁄A) is commonly used for the treatment of many disorders, such as hyperactive musculoskeletal disorders, dystonia, and pain. However, the effectiveness of BoNT⁄A for pain alleviation and the mechanisms that mediate the analgesic effects of BoNT⁄A remain unclear. To define the antinociceptive mechanisms by which BoNT/A functions, the interactions between BoNT⁄A and the transient receptor potential vanilloid subfamily 1 (TRPV1) were investigated using immunofluorescence, co-immunoprecipitation, and western blot analysis in primary mouse embryonic dorsal root ganglion neuronal cultures. Results 1) Three-week-old cultured dorsal root ganglion neurons highly expressed transient TRPV1, synaptic vesicle 2A (SV2A) and synaptosomal-associated protein 25 (SNAP-25). SV2A and SNAP-25 are the binding receptor and target protein, respectively, of BoNT⁄A. 2) TRPV1 colocalized with both BoNT⁄A and cleaved SNAP-25 when BoNT⁄A was added to dorsal root ganglia neuronal cultures. 3) After 24 hours of BoNT⁄A treatment (1 nmol⁄l), both TRPV1 and BoNT⁄A positive bands were detected in western blots of immunoprecipitated pellets. 4) Blocking TRPV1 with a specific antibody decreased the cleavage of SNAP-25 by BoNT⁄A. Conclusion BoNT/A interacts with TRPV1 both structurally and functionally in cultured mouse embryonic dorsal root ganglion neurons. These results suggest that an alternative mechanism is used by BoNT⁄A to mediate pain relief. PMID:26745805

  8. Synthesis and radioiodination of ergoline derivatives: potential in-vivo dopamine receptor site mapping radiopharmaceuticals

    SciTech Connect

    Mikhail, E.A.

    1985-01-01

    The need of a dopamine-receptor based radiopharmaceutical for brain imaging is apparent. If such an agent is made available to physicians, it could provide means for detecting brain tumors, and diagnose such mental disorders as parkinsonism, schizophrenia and psychosis. Currently, such agents are yet to be discovered. Procedures were developed to synthesize and label four ergoline derivatives which could potentially exhibit affinity to dopamine receptors. Labelling with /sup 125/I was accomplished in some cases by displacing a suitably positioned leaving group with /sup 125/I-anion, while in other cases iodine exchange procedures were utilized. Formulations of the labeled derivatives were achieved via the formation of their water soluble tartarate salts. Biodistribution studies in mature Sprague-Dawley rats showed that of the four radioactive compounds injected, the highest uptake in the brain and adrenals was achieved with 8 ..beta..-(I-125)-iodomethyl-6-propylergoline. In addition, high target/nontarget ratios were obtained with the above mentioned compound. On the other hand, the least brain and adrenal uptake as well as the lowest target/nontarget ratios were exhibited by 8 ..beta..-(I-125)-(p-iodobenzenesulfonyl)-lysergol presumably due to its in-vivo instability. A comparative biodistribution study for ergoline derivatives and N-isopropyl-(I-123)-p-iodoamphetamine was conducted. The biodistribution studies showed that the brain to blood ratio for the ergoline derivative 8 ..beta..-(I-125)-iodomethyl-6-propylergoline to be very close to that for /sup 125/I-IMP at 1 minute after dose administration. However after 15 minutes the brain/blood ratio of compound XLVI was half the value of /sup 123/I-IMP. Different mechanisms of brain influx and efflux are known to occur with the amphetamine and ergoline derivatives.

  9. Calcium regulation by temperature-sensitive transient receptor potential channels in human uveal melanoma cells.

    PubMed

    Mergler, Stefan; Derckx, Raissa; Reinach, Peter S; Garreis, Fabian; Böhm, Arina; Schmelzer, Lisa; Skosyrski, Sergej; Ramesh, Niraja; Abdelmessih, Suzette; Polat, Onur Kerem; Khajavi, Noushafarin; Riechardt, Aline Isabel

    2014-01-01

    Uveal melanoma (UM) is both the most common and fatal intraocular cancer among adults worldwide. As with all types of neoplasia, changes in Ca(2+) channel regulation can contribute to the onset and progression of this pathological condition. Transient receptor potential channels (TRPs) and cannabinoid receptor type 1 (CB1) are two different types of Ca(2+) permeation pathways that can be dysregulated during neoplasia. We determined in malignant human UM and healthy uvea and four different UM cell lines whether there is gene and functional expression of TRP subtypes and CB1 since they could serve as drug targets to either prevent or inhibit initiation and progression of UM. RT-PCR, Ca(2+) transients, immunohistochemistry and planar patch-clamp analysis probed for their gene expression and functional activity, respectively. In UM cells, TRPV1 and TRPM8 gene expression was identified. Capsaicin (CAP), menthol or icilin induced Ca(2+) transients as well as changes in ion current behavior characteristic of TRPV1 and TRPM8 expression. Such effects were blocked with either La(3+), capsazepine (CPZ) or BCTC. TRPA1 and CB1 are highly expressed in human uvea, but TRPA1 is not expressed in all UM cell lines. In UM cells, the CB1 agonist, WIN 55,212-2, induced Ca(2+) transients, which were suppressed by La(3+) and CPZ whereas CAP-induced Ca(2+) transients could also be suppressed by CB1 activation. Identification of functional TRPV1, TRPM8, TRPA1 and CB1 expression in these tissues may provide novel drug targets for treatment of this aggressive neoplastic disease.

  10. Potential for vitamin D receptor agonists in the treatment of cardiovascular disease.

    PubMed

    Wu-Wong, J R

    2009-09-01

    Vitamin D(3) is made in the skin and modified in the liver and kidney to form the active metabolite, 1,25-dihydroxyvitamin D(3) (calcitriol). Calcitriol binds to a nuclear receptor, the vitamin D receptor (VDR), and activates VDR to recruit cofactors to form a transcriptional complex that binds to vitamin D response elements in the promoter region of target genes. During the past three decades the field has focused mainly on the role of VDR in the regulation of parathyroid hormone, intestinal calcium/phosphate absorption and bone metabolism; several VDR agonists (VDRAs) have been developed for the treatment of osteoporosis, psoriasis and hyperparathyroidism secondary to chronic kidney disease (CKD). Emerging evidence suggests that VDR plays important roles in modulating cardiovascular, immunological, metabolic and other functions. For example, data from epidemiological, preclinical and clinical studies have shown that vitamin D and/or 25(OH)D deficiency is associated with increased risk for cardiovascular disease (CVD). However, VDRA therapy seems more effective than native vitamin D supplementation in modulating CVD risk factors. In CKD, where decreasing VDR activation persists over the course of the disease and a majority of the patients die of CVD, VDRA therapy was found to provide a survival benefit in both pre-dialysis and dialysis CKD patients. Although VDR plays an important role in regulating cardiovascular function and VDRAs may be potentially useful for treating CVD, at present no VDRA is approved for CVD, and also no serum markers, beside parathyroid hormone in CKD, exist to indicate the efficacy of VDRA in CVD. PMID:19371337

  11. Cannabinoid receptor signalling in neurodegenerative diseases: a potential role for membrane fluidity disturbance

    PubMed Central

    Maccarrone, M; Bernardi, G; Agrò, A Finazzi; Centonze, D

    2011-01-01

    Type-1 cannabinoid receptor (CB1) is the most abundant G-protein-coupled receptor (GPCR) in the brain. CB1 and its endogenous agonists, the so-called ‘endocannabinoids (eCBs)’, belong to an ancient neurosignalling system that plays important functions in neurodegenerative and neuroinflammatory disorders like Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis. For this reason, research on the therapeutic potential of drugs modulating the endogenous tone of eCBs is very intense. Several GPCRs reside within subdomains of the plasma membranes that contain high concentrations of cholesterol: the lipid rafts. Here, the hypothesis that changes in membrane fluidity alter function of the endocannabinoid system, as well as progression of particular neurodegenerative diseases, is described. To this end, the impact of membrane cholesterol on membrane properties and hence on neurodegenerative diseases, as well as on CB1 signalling in vitro and on CB1-dependent neurotransmission within the striatum, is discussed. Overall, present evidence points to the membrane environment as a critical regulator of signal transduction triggered by CB1, and calls for further studies aimed at better clarifying the contribution of membrane lipids to eCBs signalling. The results of these investigations might be exploited also for the development of novel therapeutics able to combat disorders associated with abnormal activity of CB1. LINKED ARTICLES This article is part of a themed issue on Cannabinoids in Biology and Medicine. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.163.issue-7 PMID:21323908

  12. Enhanced itch elicited by capsaicin in a chronic itch model

    PubMed Central

    Yu, Guang; Yang, Niuniu; Li, Fengxian; Chen, Meijuan; Guo, Changxiong J; Wang, Changming; Hu, Danyou; Yang, Yan; Zhu, Chan; Wang, Zhongli; Shi, Hao; Gegen, Tana; Tang, Ming; He, Qian

    2016-01-01

    Chronic itch (pruritus) is an important clinical problem. However, the underlying molecular basis has yet to be understood. The Transient Receptor Potential Vanilloid 1 channel is a heat-sensitive cation channel expressed in primary sensory neurons and involved in both thermosensation and pain, but its role in chronic itch remains elusive. Here, we for the first time revealed an increased innervation density of Transient Receptor Potential Vanilloid 1-expressing sensory fibers in the skin afflicted with chronic itch. Further analysis indicated that this phenomenon is due to an expansion of Transient Receptor Potential Vanilloid 1-expressing sensory neurons under chronic itch conditions. As a functional correlates of this neuronal expansion, we observed an enhanced neuronal responsiveness to capsaicin under the dry skin conditions. Importantly, the neuronal hypersensitivity to capsaicin results in itch, rather than pain sensation, suggesting that the up-regulated Transient Receptor Potential Vanilloid 1 underlies the pain-to-itch switch under chronic itchy conditions. The study shows that there are different mechanisms of chronic pain and itching, and Transient Receptor Potential Vanilloid 1 plays an important role in chronic itch. PMID:27118771

  13. Muscarinic receptor subtypes as potential targets to modulate oligodendrocyte progenitor survival, proliferation, and differentiation.

    PubMed

    De Angelis, Federica; Bernardo, Antonietta; Magnaghi, Valerio; Minghetti, Luisa; Tata, Ada Maria

    2012-05-01

    Acetylcholine (ACh) is a major neurotransmitter but also an important signaling molecule in neuron-glia interactions. Expression of ACh receptors has been reported in several glial cell populations, including oligodendrocytes (OLs). Nonetheless, the characterization of muscarinic receptors in these cells, as well as the description of the cholinergic effects at different stages of OL development, is still incomplete. In this study, we characterized the pattern of expression of muscarinic receptor subtypes in primary cultures of rat oligodendrocyte progenitor cells (OPC) and mature OLs, at both mRNA and protein levels. We found that muscarinic receptor expression is developmentally regulated. M1, M3, and M4 receptors were the main subtypes expressed in OPC, whereas all receptor subtypes were expressed at low levels in mature OLs. Exposure of OPC to muscarine enhanced cell proliferation, an effect mainly due to M1, M3, and M4 receptor subtypes as demonstrated by pharmacological competition with selective antagonists. Conversely, M2 receptor activation impaired OPC survival. In line with the mitogenic activity, muscarinic receptor activation increased the expression of platelet derived growth factor receptor α. Muscarine stimulation increased CX32 and myelin basic protein expression, left unaffected that of myelin proteolipid protein (PLP), and decreased member of the family of epidermal growth factor receptor (EGFR) ErbB3/ErbB4 receptor expression indicating a predominant role of muscarinic receptors in OPC. These findings suggest that ACh may contribute to the maintenance of an immature proliferating progenitor pool and impair the progression toward mature stage. This hypothesis is further supported by increased expression of Notch-1 in OL on muscarinic activation.

  14. Transient Receptor Potential Vanilloid 4-Induced Modulation of Voltage-Gated Sodium Channels in Hippocampal Neurons.

    PubMed

    Hong, Zhiwen; Jie, Pinghui; Tian, Yujing; Chen, Tingting; Chen, Lei; Chen, Ling

    2016-01-01

    Transient receptor potential vanilloid 4 (TRPV4) is reported to control the resting membrane potential and increase excitability in many types of cells. Voltage-gated sodium channels (VGSCs) play an important role in initiating action potentials in neurons. However, whether VGSCs can be modulated by the activation of TRPV4 in hippocampal pyramidal neurons remains unknown. In this study, we tested the effect of TRPV4 agonists (GSK1016790A and 4α-PDD) on voltage-gated sodium current (I Na) in hippocampal CA1 pyramidal neurons and the protein levels of α/β-subunit of VGSCs in the hippocampus of mice subjected to intracerebroventricular (icv.) injection of GSK1016790A (GSK-injected mice). Herein, we report that I Na was inhibited by acute application of GSK1016790A or 4α-PDD. In the presence of TRPV4 agonists, the voltage-dependent inactivation curve shifted to the hyperpolarization, whereas the voltage-dependent activation curve remained unchanged. The TRPV4 agonist-induced inhibition of I Na was blocked by the TRPV4 antagonist or tetrodotoxin. Moreover, blocking protein kinase A (PKA) markedly attenuated the GSK1016790A-induced inhibition of I Na, whereas antagonism of protein kinase C or p38 mitogen-activated protein kinase did not change GSK1016790A action. Finally, the protein levels of Nav1.1, Nav1.2, and Nav1.6 in the hippocampus increased in GSK-injected mice, whereas those of Nav1.3 and Navβ1 remained nearly unchanged. We conclude that I Na is inhibited by the acute activation of TRPV4 through PKA signaling pathway in hippocampal pyramidal neurons, but protein expression of α-subunit of VGSCs is increased by sustained TRPV4 activation, which may compensate for the acute inhibition of I Na and provide a possibility for hyper-excitability upon sustained TRPV4 activation.

  15. Adropin acts in brain to inhibit water drinking: potential interaction with the orphan G protein-coupled receptor, GPR19.

    PubMed

    Stein, Lauren M; Yosten, Gina L C; Samson, Willis K

    2016-03-15

    Adropin, a recently described peptide hormone produced in the brain and liver, has been reported to have physiologically relevant actions on glucose homeostasis and lipogenesis, and to exert significant effect on endothelial function. We describe a central nervous system action of adropin to inhibit water drinking and identify a potential adropin receptor, the orphan G protein-coupled receptor, GPR19. Reduction in GPR19 mRNA levels in medial basal hypothalamus of male rats resulted in the loss of the inhibitory effect of adropin on water deprivation-induced thirst. The identification of a novel brain action of adropin and a candidate receptor for the peptide should extend and accelerate the study of the potential therapeutic value of adropin or its mimetics for the treatment of metabolic disorders. PMID:26739651

  16. Bimodal concentration-response of nicotine involves the nicotinic acetylcholine receptor, transient receptor potential vanilloid type 1, and transient receptor potential ankyrin 1 channels in mouse trachea and sensory neurons.

    PubMed

    Kichko, Tatjana I; Lennerz, Jochen; Eberhardt, Mirjam; Babes, Ramona M; Neuhuber, Winfried; Kobal, Gerd; Reeh, Peter W

    2013-11-01

    High concentrations of nicotine, as in the saliva of oral tobacco consumers or in smoking cessation aids, have been shown to sensitize/activate recombinant transient receptor potential vanilloid type 1 (rTRPV1) and mouse TRPA1 (mTRPA1) channels. By measuring stimulated calcitonin gene-related peptide (CGRP) release from the isolated mouse trachea, we established a bimodal concentration-response relationship with a threshold below 10 µM (-)-nicotine, a maximum at 100 µM, an apparent nadir between 0.5 and 10 mM, and a renewed increase at 20 mM. The first peak was unchanged in TRPV1/A1 double-null mutants as compared with wild-types and was abolished by specific nicotinic acetylcholine receptor (nAChR) inhibitors and by camphor, discovered to act as nicotinic antagonist. The nicotine response at 20 mM was strongly pHe-dependent, - five times greater at pH 9.0 than 7.4, indicating that intracellular permeation of the (uncharged) alkaloid was required to reach the TRPV1/A1 binding sites. The response was strongly reduced in both null mutants, and more so in double-null mutants. Upon measuring calcium transients in nodose/jugular and dorsal root ganglion neurons in response to 100 µM nicotine, 48% of the vagal (but only 14% of the somatic) sensory neurons were activated, the latter very weakly. However, nicotine 20 mM at pH 9.0 repeatedly activated almost every single cultured neuron, partly by releasing intracellular calcium and independent of TRPV1/A1 and nAChRs. In conclusion, in mouse tracheal sensory nerves nAChRs are 200-fold more sensitive to nicotine than TRPV1/A1; they are widely coexpressed with the capsaicin receptor among vagal sensory neurons and twice as abundant as TRPA1. Nicotine is the major stimulant in tobacco, and its sensory impact through nAChRs should not be disregarded.

  17. A novel human volunteer pain model using contact heat evoked potentials (CHEP) following topical skin application of transient receptor potential agonists capsaicin, menthol and cinnamaldehyde.

    PubMed

    Roberts, K; Shenoy, R; Anand, P

    2011-07-01

    The discovery of transient receptor potential (TRP) receptors has advanced understanding of temperature sensation, and pre-clinical studies have identified TRP as major novel analgesic targets in inflammatory and neuropathic pain states. We systematically investigated the sensory effects and interactions of TRP agonists capsaicin (TRPV1), menthol (TRPM8) and cinnamaldehyde (TRPA1) applied topically to the skin in 14 healthy human participants. Capsaicin lowered heat pain thresholds while warm detection thresholds were unchanged, suggesting an effect purely on nociceptor nerve fibres. The amplitude of contact heat-evoked potentials (CHEP) and evoked pain ratings were negatively correlated after capsaicin, whereas CHEP had been correlated positively without capsaicin in a previous volunteer study. Menthol caused cold hypersensitivity and cinnamaldehyde caused heat hypersensitivity, but neither had an effect on evoked potentials. The CHEP after application of capsaicin show features observed in some patients with painful neuropathy, and could provide a model for development of novel analgesics, particularly TRPV1 antagonists.

  18. Sensitivity of bronchopulmonary receptors to cold and heat mediated by transient receptor potential cation channel subtypes in an ex vivo rat lung preparation.

    PubMed

    Zhou, Yun; Sun, Biying; Li, Qian; Luo, Pin; Dong, Li; Rong, Weifang

    2011-08-15

    Changes in airway temperature can result in respiratory responses such as cough, bronchoconstriction and mucosal secretion after cold exposure and hyperventilation after heat exposure. In the present investigation, we examined the activity of bronchopulmonary receptors in response to activators of thermo-sensitive transient receptor potential (TS-TRP) cation channels using an ex vivo rat lung preparation. Receptive fields in small bronchioles were probed with von Frey hair monofilaments, warm (50°C) or cold (8°C) saline or saline containing TS-TRP agonists. Among 233 fibers tested, 159 (68.2%) responded to heat (50°C). A large proportion of heat-responsive receptors (107/145) were also activated by capsaicin. Heat and capsaicin-evoked responses were both blocked by TRPV1 antagonist, capsazepine. Only 15.3% of airway receptors responded to cold, which was associated with sensitivity to TRPM8 agonist menthol but not to TRPA1 agonist cinnamaldehyde (CA). Moreover, cold-evoked responses was unaffected by TRPA1 antagonist HC-03001. Our observations suggest that TRPV1 and TRPM8 are involved in transducing heat and cold in the lower respiratory tract, respectively.

  19. Dopamine D3 Receptor Antagonist (GSK598809) Potentiates the Hypertensive Effects of Cocaine in Conscious, Freely-Moving Dogs.

    PubMed

    Appel, Nathan M; Li, Shou-Hua; Holmes, Tyson H; Acri, Jane B

    2015-09-01

    The chronic and relapsing nature of addiction presents unique challenges for ensuring the safety of a potential medication. A patient may use cocaine, for example, while taking the medication or take more medication than prescribed. Thus, a potential medication must be safe and not exacerbate the effects of cocaine. Multiple published studies support antagonism of brain dopamine D3 receptor function as a potential mechanism of action for an anti-addiction medication. Dopamine D3 receptors are widely distributed outside the central nervous system, however; for example, dopamine D3 receptors in the kidneys are implicated in regulating blood pressure. The selective dopamine D3 receptor antagonist GSK598809 [1-(2-fluoro-4-trifluoromethyl-phenyl)-3-{3-[4-methyl-5-(4-methyl-oxazol-5-yl)-4H-[1,2,4]triazol-3-ylsulfanyl]-propyl}-3-aza-bicyclo[3.1.0]hexane] has been proposed as a medication to treat cocaine and other substance use disorders. The US Food and Drug Administration has established guidelines recommending safety studies to investigate potential undesirable pharmacodynamic effects of a substance in relation to exposure in the therapeutic range and above. Hence, we assessed the interaction between this selective dopamine D3 receptor antagonist and cocaine on hemodynamics and cardiac function in freely-moving, telemetered dogs before conducting a clinical trial. GSK598809 increased the hemodynamic effect of cocaine in this model. Thus, the increase in blood pressure after intravenous cocaine was greater in animals that had been pretreated with GSK598809 compared with vehicle. This finding suggests that GSK598809 in particular, and perhaps dopamine D3 receptor antagonists as a class, may produce unacceptable cardiovascular risks as medications to treat cocaine use disorder. PMID:26177654

  20. Dopamine D3 Receptor Antagonist (GSK598809) Potentiates the Hypertensive Effects of Cocaine in Conscious, Freely-Moving Dogs

    PubMed Central

    Li, Shou-Hua; Holmes, Tyson H.; Acri, Jane B.

    2015-01-01

    The chronic and relapsing nature of addiction presents unique challenges for ensuring the safety of a potential medication. A patient may use cocaine, for example, while taking the medication or take more medication than prescribed. Thus, a potential medication must be safe and not exacerbate the effects of cocaine. Multiple published studies support antagonism of brain dopamine D3 receptor function as a potential mechanism of action for an anti-addiction medication. Dopamine D3 receptors are widely distributed outside the central nervous system, however; for example, dopamine D3 receptors in the kidneys are implicated in regulating blood pressure. The selective dopamine D3 receptor antagonist GSK598809 [1-(2-fluoro-4-trifluoromethyl-phenyl)-3-{3-[4-methyl-5-(4-methyl-oxazol-5-yl)-4H-[1,2,4]triazol-3-ylsulfanyl]-propyl}-3-aza-bicyclo[3.1.0]hexane] has been proposed as a medication to treat cocaine and other substance use disorders. The US Food and Drug Administration has established guidelines recommending safety studies to investigate potential undesirable pharmacodynamic effects of a substance in relation to exposure in the therapeutic range and above. Hence, we assessed the interaction between this selective dopamine D3 receptor antagonist and cocaine on hemodynamics and cardiac function in freely-moving, telemetered dogs before conducting a clinical trial. GSK598809 increased the hemodynamic effect of cocaine in this model. Thus, the increase in blood pressure after intravenous cocaine was greater in animals that had been pretreated with GSK598809 compared with vehicle. This finding suggests that GSK598809 in particular, and perhaps dopamine D3 receptor antagonists as a class, may produce unacceptable cardiovascular risks as medications to treat cocaine use disorder. PMID:26177654

  1. Blockade of peripheral P2Y1 receptors prevents the induction of thermal hyperalgesia via modulation of TRPV1 expression in carrageenan-induced inflammatory pain rats: involvement of p38 MAPK phosphorylation in DRGs.

    PubMed

    Kwon, Soon-Gu; Roh, Dae-Hyun; Yoon, Seo-Yeon; Moon, Ji-Young; Choi, Sheu-Ran; Choi, Hoon-Seong; Kang, Suk-Yun; Han, Ho-Jae; Beitz, Alvin J; Lee, Jang-Hern

    2014-04-01

    Although previous reports have suggested that P2Y1 receptors (P2Y1Rs) are involved in cutaneous nociceptive signaling, it remains unclear how P2Y1Rs contribute to peripheral sensitization. The current study was designed to delineate the role of peripheral P2Y1Rs in pain and to investigate potential linkages to mitogen-activated protein kinase (MAPK) in DRGs and Transient Receptor Potential Vanilloid 1 (TRPV1) expression in a rodent inflammatory pain model. Following injection of 2% carrageenan into the hind paw, expressions of P2Y1 and TRPV1 and the phosphorylation rates of both p38 MAPK and ERK but not JNK were increased and peaked at day 2 post-injection. Blockade of peripheral P2Y1Rs by the P2Y1R antagonist, MRS2500 injection (i.pl, D0 to D2) significantly reduced the induction of thermal hyperalgesia, but not mechanical allodynia. Simultaneously, MRS2500 injections suppressed upregulated TRPV1 expression and DRG p38 phosphorylation, while pERK signaling was not affected. Furthermore, inhibition of p38 activation in the DRGs by SB203580 (a p38 inhibitor, i.t, D0 to D2) prevented the upregulation of TRPV1 and a single i.t injection of SB203580 reversed the established thermal hyperalgesia, but not mechanical allodynia. Lastly, to identify the mechanism of action of P2Y1Rs, we repeatedly injected the P2Y1 agonist, MRS2365 into the naïve rat's hind paw and observed a dose-dependent increase in TRPV1 expression and p38 MAPK phosphorylation. These data demonstrate a sequential role for P2Y1R, p38 MAPK and TRPV1 in inflammation-induced thermal hyperalgesia; thus, peripheral P2Y1Rs activation modulates p38 MAPK signaling and TRPV1 expression, which ultimately leads to the induction of thermal hyperalgesia. PMID:24333674

  2. Potentiation and suppression of the histamine response by raising and lowering the temperature in canine visceral polymodal receptors in vitro.

    PubMed

    Mizumura, K; Koda, H

    1999-04-30

    It is well known that itch and inflammatory pain are enhanced when tissue is warmed, while they are suppressed when tissue is cooled. To see whether these changed sensations are based on the changed response of sensory receptors, the temperature dependency of the excitation of polymodal receptors induced by histamine, which plays an important role both in itch and inflammatory pain, was studied. Single nerve activities of polymodal receptors were recorded from canine testis-spermatic nerve preparations in vitro. Raising the temperature from 34 to 40 degrees C, a temperature below the threshold for the heat response of polymodal receptors, facilitated the histamine-induced nerve discharge to 268% of that at 34 degrees C, while lowering the temperature to 28 degrees C decreased it to 25%. Facilitation of the histamine response was also observed in the noxious temperature range (48 and 51 degrees C). These results suggest that the potentiation of the histamine-induced sensation by increasing the tissue temperature, as well as its suppression by lowering tissue temperature, can be explained by a temperature-dependent response of peripheral sensory receptors to histamine. However, the suppression of itch by noxious heat reported by Bickford (Bickford, R.G., Experiments relating to the itch sensation, its peripheral mechanism, and central pathways, Clin. Sci. Incorp. Heart, 3 (1937) 377-386) cannot be explained by the noxious heat-induced facilitation of the peripheral receptor response reported in this paper.

  3. Loss of D2 dopamine receptor function modulates cocaine-induced glutamatergic synaptic potentiation in the ventral tegmental area.

    PubMed

    Madhavan, Anuradha; Argilli, Emanuela; Bonci, Antonello; Whistler, Jennifer L

    2013-07-24

    Potentiation of glutamate responses is a critical synaptic response to cocaine exposure in ventral tegmental area (VTA) neurons. However, the mechanism by which cocaine exposure promotes potentiation of NMDA receptors (NMDARs) and subsequently AMPA receptors (AMPARs) is not fully understood. In this study we demonstrate that repeated cocaine treatment causes loss of D2 dopamine receptor functional responses via interaction with lysosome-targeting G-protein-associated sorting protein1 (GASP1). We also show that the absence of D2 downregulation in GASP1-KO mice prevents cocaine-induced potentiation of NMDAR currents, elevation of the AMPA/NMDA ratio, and redistribution of NMDAR and AMPAR subunits to the membrane. As a pharmacological parallel, coadministration of the high-affinity D2 agonist, aripiprazole, reduces not only functional downregulation of D2s in response to cocaine but also potentiation of NMDAR and AMPAR responses in wild-type mice. Together these data suggest that functional loss of D2 receptors is a critical mechanism mediating cocaine-induced glutamate plasticity in VTA neurons.

  4. Loss of D2 Dopamine Receptor Function Modulates Cocaine-Induced Glutamatergic Synaptic Potentiation in the Ventral Tegmental Area

    PubMed Central

    Madhavan, Anuradha; Argilli, Emanuela; Bonci, Antonello

    2013-01-01

    Potentiation of glutamate responses is a critical synaptic response to cocaine exposure in ventral tegmental area (VTA) neurons. However, the mechanism by which cocaine exposure promotes potentiation of NMDA receptors (NMDARs) and subsequently AMPA receptors (AMPARs) is not fully understood. In this study we demonstrate that repeated cocaine treatment causes loss of D2 dopamine receptor functional responses via interaction with lysosome-targeting G-protein-associated sorting protein1 (GASP1). We also show that the absence of D2 downregulation in GASP1-KO mice prevents cocaine-induced potentiation of NMDAR currents, elevation of the AMPA/NMDA ratio, and redistribution of NMDAR and AMPAR subunits to the membrane. As a pharmacological parallel, coadministration of the high-affinity D2 agonist, aripiprazole, reduces not only functional downregulation of D2s in response to cocaine but also potentiation of NMDAR and AMPAR responses in wild-type mice. Together these data suggest that functional loss of D2 receptors is a critical mechanism mediating cocaine-induced glutamate plasticity in VTA neurons. PMID:23884939

  5. Loss of D2 dopamine receptor function modulates cocaine-induced glutamatergic synaptic potentiation in the ventral tegmental area.

    PubMed

    Madhavan, Anuradha; Argilli, Emanuela; Bonci, Antonello; Whistler, Jennifer L

    2013-07-24

    Potentiation of glutamate responses is a critical synaptic response to cocaine exposure in ventral tegmental area (VTA) neurons. However, the mechanism by which cocaine exposure promotes potentiation of NMDA receptors (NMDARs) and subsequently AMPA receptors (AMPARs) is not fully understood. In this study we demonstrate that repeated cocaine treatment causes loss of D2 dopamine receptor functional responses via interaction with lysosome-targeting G-protein-associated sorting protein1 (GASP1). We also show that the absence of D2 downregulation in GASP1-KO mice prevents cocaine-induced potentiation of NMDAR currents, elevation of the AMPA/NMDA ratio, and redistribution of NMDAR and AMPAR subunits to the membrane. As a pharmacological parallel, coadministration of the high-affinity D2 agonist, aripiprazole, reduces not only functional downregulation of D2s in response to cocaine but also potentiation of NMDAR and AMPAR responses in wild-type mice. Together these data suggest that functional loss of D2 receptors is a critical mechanism mediating cocaine-induced glutamate plasticity in VTA neurons. PMID:23884939

  6. Activation of Group II Metabotropic Glutamate Receptors Induces Depotentiation in Amygdala Slices and Reduces Fear-Potentiated Startle in Rats

    ERIC Educational Resources Information Center

    Lin, Chia-Ho; Lee, Chia-Ching; Huang, Ya-Chun; Wang, Su-Jane; Gean, Po-Wu

    2005-01-01

    There is a close correlation between long-term potentiation (LTP) in the synapses of lateral amygdala (LA) and fear conditioning in animals. We predict that reversal of LTP (depotentiation) in this area of the brain may ameliorate conditioned fear. Activation of group II metabotropic glutamate receptors (mGluR II) with DCG-IV induces…

  7. Effect of Maillard Reacted Peptides on Human Salt Taste and the Amiloride-Insensitive Salt Taste Receptor (TRPV1t)

    PubMed Central

    Katsumata, Tadayoshi; Nakakuki, Hiroko; Tokunaga, Chikara; Fujii, Noboru; Egi, Makoto; Phan, Tam-Hao T.; Mummalaneni, Shobha; DeSimone, John A.

    2008-01-01

    Maillard reacted peptides (MRPs) were synthesized by conjugating a peptide fraction (1000–5000 Da) purified from soy protein hydrolyzate with galacturonic acid, glucosamine, xylose, fructose, or glucose. The effect of MRPs was investigated on human salt taste and on the chorda tympani (CT) taste nerve responses to NaCl in Sprague–Dawley rats, wild-type, and transient receptor potential vanilloid 1 (TRPV1) knockout mice. MRPs produced a biphasic effect on human salt taste perception and on the CT responses in rats and wild-type mice in the presence of NaCl + benzamil (Bz, a blocker of epithelial Na+ channels), enhancing the NaCl response at low concentrations and suppressing it at high concentrations. The effectiveness of MRPs as salt taste enhancers varied with the conjugated sugar moiety: galacturonic acid = glucosamine > xylose > fructose > glucose. The concentrations at which MRPs enhanced human salt taste were significantly lower than the concentrations of MRPs that produced increase in the NaCl CT response. Elevated temperature, resiniferatoxin, capsaicin, and ethanol produced additive effects on the NaCl CT responses in the presence of MRPs. Elevated temperature and ethanol also enhanced human salt taste perception. N-(3-methoxyphenyl)-4-chlorocinnamid (a blocker of TRPV1t) inhibited the Bz-insensitive NaCl CT responses in the absence and presence of MRPs. TRPV1 knockout mice demonstrated no Bz-insensitive NaCl CT response in the absence or presence of MRPs. The results suggest that MRPs modulate human salt taste and the NaCl + Bz CT responses by interacting with TRPV1t. PMID:18603652

  8. Interaction of new antidepressants with sigma-1 receptor chaperones and their potentiation of neurite outgrowth in PC12 cells.

    PubMed

    Ishima, Tamaki; Fujita, Yuko; Hashimoto, Kenji

    2014-03-15

    The sigma-1 receptor chaperone located in the endoplasmic reticulum (ER) may be implicated in the mechanistic action of some antidepressants. The present study was undertaken to examine whether new antidepressant drugs interact with the sigma-1 receptor chaperone. First, we examined the effects of selective serotonin reuptake inhibitors (SSRIs) (fluvoxamine, paroxetine, sertraline, citalopram and escitalopram), serotonin and noradrenaline reuptake inhibitors (SNRIs) (duloxetine, venlafaxine, milnacipran), and mirtazapine, a noradrenaline and specific serotonergic antidepressant (NaSSA), on [(3)H](+)-pentazocine binding to rat brain membranes. Then, we examined the effects of these drugs on nerve growth factor (NGF)-induced neurite outgrowth in PC12 cells. The order of potency for drugs at the sigma-1 receptor chaperone was as follows: fluvoxamine>sertraline>fluoxetine>escitalopram>citalopram>paroxetine>duoxetine. Venlafaxine, milnacipran, and mirtazapine showed very weak affinity for this chaperone. Furthermore, fluvoxamine, fluoxetine, escitalopram, and mirtazapine significantly potentiated NGF-induced neurite outgrowth in cell assays, and the effects of all these drugs, excluding mirtazapine, were antagonized by NE-100, a selective antagonist of the sigma-1 receptor chaperone. Moreover, the effects of fluvoxamine and fluoxetine on neurite outgrowth were also antagonized by sertraline, indicating that sertraline may be an antagonist at the sigma-1 receptor chaperone. The effect of mirtazapine on neurite outgrowth was antagonized by the selective 5-hydroxytryptamine1A receptor antagonist WAY-100635. These findings suggest that activation at the sigma-1 receptor chaperone may be involved in the action of some SSRIs, such as fluvoxamine, fluoxetine and escitalopram. In contrast, mirtazapine independently potentiated neurite outgrowth in PC12 cells, indicating that this beneficial effect may mediate its pharmacological effect. PMID:24508523

  9. Dopamine D₁-D₂ receptor heteromer regulates signaling cascades involved in addiction: potential relevance to adolescent drug susceptibility.

    PubMed

    Perreault, Melissa L; O'Dowd, Brian F; George, Susan R

    2014-01-01

    Adolescence is a developmental period that has been associated with heightened sensitivity to psychostimulant-induced reward, thus placing adolescents at increased risk to develop drug addiction. Although alterations in dopamine-induced synaptic plasticity are perhaps the most critical factor in mediating addiction processes, developmental differences in the cell signaling mechanisms that contribute to synaptic plasticity, and their contribution to adolescent reward sensitivity, has been grossly understudied. The most abundant dopamine receptors, the D1 and D2 receptors, as well as the dopamine D1-D2 receptor heteromer, exhibit age-dependent and brain region-specific changes in their expression and function and are responsible for regulating cell signaling pathways known to significantly contribute to the neurobiological mechanisms underlying addiction. The D1-D2 receptor heteromer, for instance, has been associated with calcium calmodulin kinase IIα, brain-derived neurotrophic factor and glycogen synthase kinase 3 (GSK-3) signaling, three proteins highly implicated in the regulation of glutamate transmission and synaptic plasticity and which regulate addiction to amphetamine, opioids and cocaine. Therefore, in this review the importance of these signaling proteins as potential mediators of addiction susceptibility in adolescence will be highlighted, and the therapeutic potential of the D1-D2 receptor heteromer in addiction will be discussed. It is the overall goal of this review to draw attention to the research gap in dopamine-induced cell signaling in the adolescent brain--knowledge that would provide much-needed insights into adolescent addiction vulnerability. PMID:24820626

  10. Corticotropin-releasing factor (CRF) and α 2 adrenergic receptors mediate heroin withdrawal-potentiated startle in rats.

    PubMed

    Park, Paula E; Vendruscolo, Leandro F; Schlosburg, Joel E; Edwards, Scott; Schulteis, Gery; Koob, George F

    2013-09-01

    Anxiety is one of the early symptoms of opioid withdrawal and contributes to continued drug use and relapse. The acoustic startle response (ASR) is a component of anxiety that has been shown to increase during opioid withdrawal in both humans and animals. We investigated the role of corticotropin-releasing factor (CRF) and norepinephrine (NE), two key mediators of the brain stress system, on acute heroin withdrawal-potentiated ASR. Rats injected with heroin (2 mg/kg s.c.) displayed an increased ASR when tested 4 h after heroin treatment. A similar increase in ASR was found in rats 10-20 h into withdrawal from extended access (12 h) to i.v. heroin self-administration, a model that captures several aspects of heroin addiction in humans. Both the α 2 adrenergic receptor agonist clonidine (10 μg/kg s.c.) and CRF1 receptor antagonist N,N-bis(2-methoxyethyl)-3-(4-methoxy-2-methylphenyl)-2,5-dimethyl-pyrazolo[1,5-a] pyrimidin-7-amine (MPZP; 20 mg/kg s.c.) blocked heroin withdrawal-potentiated startle. To investigate the relationship between CRF1 and α 2 adrenergic receptors in the potentiation of the ASR, we tested the effect of MPZP on yohimbine (1.25 mg/kg s.c.)-potentiated startle and clonidine on CRF (2 μg i.c.v.)-potentiated startle. Clonidine blocked CRF-potentiated startle, whereas MPZP partially attenuated but did not reverse yohimbine-potentiated startle, suggesting that CRF may drive NE release to potentiate startle. These results suggest that CRF1 and α 2 receptors play an important role in the heightened anxiety-like behaviour observed during acute withdrawal from heroin, possibly via CRF inducing the release of NE in stress-related brain regions.

  11. Androgen receptor cofactors in prostate cancer: potential therapeutic targets of castration-resistant prostate cancer.

    PubMed

    Shiota, Masaki; Yokomizo, Akira; Fujimoto, Naohiro; Naito, Seiji

    2011-09-01

    Androgens, acting through the androgen receptor (AR), are responsible for many male reproductive and nonreproductive functions. Moreover, aberrant androgen/AR signaling plays a critical role in androgen-dependent prostate cancer (PCa) as well as castration-resistant prostate cancer (CRPC). The formation of a productive AR transcriptional complex requires AR cofactors that interact functionally and structurally with the AR. Since the discovery of the first such cofactor in 1995, an ever increasing number of proteins have been identified as AR coactivators or corepressors. The expression and function of several AR cofactors have been investigated in PCa, and a clear link between AR cofactors and the development and progression of PCa has been identified. Recently, AR splice variants in CRPC were reported, which display significant constitutive activity in the absence of ligand. Then, this discovery revolutionized the concept of AR cofactors in CRPC. The current review aims to provide an overview of AR cofactor proteins in the context of PCa. In addition, we discuss the potential of AR cofactors as novel therapeutic targets for PCa, particularly for CRPC.

  12. Analysis of factors influencing moxibustion efficacy by affecting heat-activated transient receptor potential vanilloid channels.

    PubMed

    Jiang, Jinfeng; Wang, Xinjun; Wu, Xiaojing; Yu, Zhi

    2016-04-01

    Moxibustion is an important component part of Traditional Chinese Medicine (TCM). Among differ- ent kinds of moxibustion methods, thermal stimulation seems to be a pivotal impact factor to the theraputic efficacy. Based on its thermal characteristic and treated area-skin, we hypothesize that the thermosensitive TRPV channels may involve in the mechanism of moxibustion. This study, by referring to various experimental and clinical data, analyzes the properties and features of transient receptor potential vanilloid (TRPV) subfamily 1-4 and the impact of moxibustion on these channels. The factors impacting the efficacy of moxibustion treatment were analyzed on three levels: the independent basic factors of moxibustion (temperature, space and time); moxibustion intensity (a compound factor achieved through comprehensive control of the three individual basic factors mentioned above); and moxibustion quantity (the amount of temperature stimulation applied within a certain unit of time, including the total amount of moxibustion treatment). The results from present study show that the effect of moxibustion therapy appears to be determined by the activation of TRPV1-4, mainly TRPV1 and TRPV2. Temperature (the degree of heat stimulation), time and area (how long the treatment lasts and how many TRPV1-4 channels are activated) affect the intensity of moxibustion treatment to form effective moxibustion quantity; this should be considered in clinical moxibustion application.

  13. Analysis of factors influencing moxibustion efficacy by affecting heat-activated transient receptor potential vanilloid channels.

    PubMed

    Jiang, Jinfeng; Wang, Xinjun; Wu, Xiaojing; Yu, Zhi

    2016-04-01

    Moxibustion is an important component part of Traditional Chinese Medicine (TCM). Among differ- ent kinds of moxibustion methods, thermal stimulation seems to be a pivotal impact factor to the theraputic efficacy. Based on its thermal characteristic and treated area-skin, we hypothesize that the thermosensitive TRPV channels may involve in the mechanism of moxibustion. This study, by referring to various experimental and clinical data, analyzes the properties and features of transient receptor potential vanilloid (TRPV) subfamily 1-4 and the impact of moxibustion on these channels. The factors impacting the efficacy of moxibustion treatment were analyzed on three levels: the independent basic factors of moxibustion (temperature, space and time); moxibustion intensity (a compound factor achieved through comprehensive control of the three individual basic factors mentioned above); and moxibustion quantity (the amount of temperature stimulation applied within a certain unit of time, including the total amount of moxibustion treatment). The results from present study show that the effect of moxibustion therapy appears to be determined by the activation of TRPV1-4, mainly TRPV1 and TRPV2. Temperature (the degree of heat stimulation), time and area (how long the treatment lasts and how many TRPV1-4 channels are activated) affect the intensity of moxibustion treatment to form effective moxibustion quantity; this should be considered in clinical moxibustion application. PMID:27400483

  14. A Novel Homozygous Mutation in the Transient Receptor Potential Melastatin 6 Gene: A Case Report

    PubMed Central

    Altıncık, Ayça; Schlingmann, Karl Peter; Tosun, Mahya Sultan

    2016-01-01

    Hereditary hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease caused by mutations in the transient receptor potential melastatin 6 (TRPM6) gene. Affected individuals present in early infancy with seizures caused by the severe hypocalcemia and hypomagnesemia. By presenting this case report, we also aimed to highlight the need for molecular genetic analysis in inbred or familial cases with hypomagnesemia. A Turkish inbred girl, now aged six years, had presented to another hospital at age two months with seizures diagnosed to be due to hypomagnesemia. She was on magnesium replacement therapy when she was admitted to our clinic with complaints of chronic diarrhea at age 3.6 years. During her follow-up in our clinic, she showed an age-appropriate physical and neurological development. In molecular genetic analysis, a novel homozygous frame-shift mutation (c.3447delT>p.F1149fs) was identified in the TRPM6 gene. This mutation leads to a truncation of the TRPM6 protein, thereby complete loss of function. We present the clinical follow-up findings of a pediatric HSH case due to a novel mutation in the TRPM6 gene and highlight the need for molecular genetic analysis in inbred or familial cases with hypomagnesemia. PMID:26759217

  15. Pathway Analysis Revealed Potential Diverse Health Impacts of Flavonoids that Bind Estrogen Receptors

    PubMed Central

    Ye, Hao; Ng, Hui Wen; Sakkiah, Sugunadevi; Ge, Weigong; Perkins, Roger; Tong, Weida; Hong, Huixiao

    2016-01-01

    Flavonoids are frequently used as dietary supplements in the absence of research evidence regarding health benefits or toxicity. Furthermore, ingested doses could far exceed those received from diet in the course of normal living. Some flavonoids exhibit binding to estrogen receptors (ERs) with consequential vigilance by regulatory authorities at the U.S. EPA and FDA. Regulatory authorities must consider both beneficial claims and potential adverse effects, warranting the increases in research that has spanned almost two decades. Here, we report pathway enrichment of 14 targets from the Comparative Toxicogenomics Database (CTD) and the Herbal Ingredients’ Targets (HIT) database for 22 flavonoids that bind ERs. The selected flavonoids are confirmed ER binders from our earlier studies, and were here found in mainly involved in three types of biological processes, ER regulation, estrogen metabolism and synthesis, and apoptosis. Besides cancers, we conjecture that the flavonoids may affect several diseases via apoptosis pathways. Diseases such as amyotrophic lateral sclerosis, viral myocarditis and non-alcoholic fatty liver disease could be implicated. More generally, apoptosis processes may be importantly evolved biological functions of flavonoids that bind ERs and high dose ingestion of those flavonoids could adversely disrupt the cellular apoptosis process. PMID:27023590

  16. Canonical transient receptor potential 1 channel is involved in contractile function of glomerular mesangial cells.

    PubMed

    Du, Juan; Sours-Brothers, Sherry; Coleman, Rashadd; Ding, Min; Graham, Sarabeth; Kong, De-Hu; Ma, Rong

    2007-05-01

    Contractility of mesangial cells (MC) is tightly controlled by [Ca(2+)](i). Ca(2+) influx across the plasma membrane constitutes a major component of mesangial responses to vasoconstrictors. Canonical transient receptor potential 1 (TRPC1) is a Ca(2+)-permeable cation channel in a variety of cell types. This study was performed to investigate whether TRPC1 takes part in vasoconstrictor-induced mesangial contraction by mediating Ca(2+) entry. It was found that angiotensin II (AngII) evoked remarkable contraction of the cultured MC. Downregulation of TRPC1 using RNA interference significantly attenuated the contractile response. Infusion of AngII or endothelin-1 in rats caused a decrease in GFR. The GFR decline was significantly reduced by infusion of TRPC1 antibody that targets an extracellular domain in the pore region of TRPC1 channel. However, the treatment of TRPC1 antibody did not affect the AngII-induced vasopressing effect. Electrophysiologic experiments revealed that functional or biologic inhibition of TRPC1 significantly depressed AngII-induced channel activation. Fura-2 fluorescence-indicated that Ca(2+) entry in response to AngII stimulation was also dramatically inhibited by TRPC1 antibody and TRPC1-specific RNA interference. These results suggest that TRPC1 plays an important role in controlling contractile function of MC. Mediation of Ca(2+) entry might be the underlying mechanism for the TRPC1-associated MC contraction. PMID:17389736

  17. Antagonism of NMDA receptors as a potential treatment for Down syndrome: a pilot randomized controlled trial

    PubMed Central

    Boada, R; Hutaff-Lee, C; Schrader, A; Weitzenkamp, D; Benke, T A; Goldson, E J; Costa, A C S

    2012-01-01

    Down syndrome (DS) is the most common genetic cause of intellectual disability. The N-methyl-D-aspartate (NMDA) receptor uncompetitive antagonist, memantine hydrochloride (memantine), has been shown to improve learning/memory and rescue one form of hippocampus synaptic plasticity dysfunction in the best-studied mouse model of DS available, the Ts65Dn mouse. Given the status of memantine as a treatment for Alzheimer's disease (AD) approved by the Food and Drug Administration, the preclinical evidence of potential efficacy in Ts65Dn mice, and the favorable safety profile of memantine, we designed a study to investigate whether the findings in the mouse model could be translated to individuals with DS. In this pilot, proof-of-principle study we hypothesized that memantine therapy would improve test scores of young adults with DS on measures of episodic and spatial memory, which are generally considered to be hippocampus dependent. Accordingly, in this randomized, double-blind, placebo-controlled trial, we compared the effect of 16-week treatment with either memantine or placebo on cognitive and adaptive functions of 40 young adults with DS using a carefully selected set of neuropsychological outcome measures. Safety and tolerability were also monitored. Although no significant differences were observed between the memantine and placebo groups on the two primary outcome measures, we found a significant improvement in the memantine group in one of the secondary measures associated with the primary hypothesis. Only infrequent and mild adverse events were noted. PMID:22806212

  18. Antagonism of NMDA receptors as a potential treatment for Down syndrome: a pilot randomized controlled trial.

    PubMed

    Boada, R; Hutaff-Lee, C; Schrader, A; Weitzenkamp, D; Benke, T A; Goldson, E J; Costa, A C S

    2012-01-01

    Down syndrome (DS) is the most common genetic cause of intellectual disability. The N-methyl-D-aspartate (NMDA) receptor uncompetitive antagonist, memantine hydrochloride (memantine), has been shown to improve learning/memory and rescue one form of hippocampus synaptic plasticity dysfunction in the best-studied mouse model of DS available, the Ts65Dn mouse. Given the status of memantine as a treatment for Alzheimer's disease (AD) approved by the Food and Drug Administration, the preclinical evidence of potential efficacy in Ts65Dn mice, and the favorable safety profile of memantine, we designed a study to investigate whether the findings in the mouse model could be translated to individuals with DS. In this pilot, proof-of-principle study we hypothesized that memantine therapy would improve test scores of young adults with DS on measures of episodic and spatial memory, which are generally considered to be hippocampus dependent. Accordingly, in this randomized, double-blind, placebo-controlled trial, we compared the effect of 16-week treatment with either memantine or placebo on cognitive and adaptive functions of 40 young adults with DS using a carefully selected set of neuropsychological outcome measures. Safety and tolerability were also monitored. Although no significant differences were observed between the memantine and placebo groups on the two primary outcome measures, we found a significant improvement in the memantine group in one of the secondary measures associated with the primary hypothesis. Only infrequent and mild adverse events were noted. PMID:22806212

  19. Methylglyoxal Activates Nociceptors through Transient Receptor Potential Channel A1 (TRPA1)

    PubMed Central

    Eberhardt, Mirjam J.; Filipovic, Milos R.; Leffler, Andreas; de la Roche, Jeanne; Kistner, Katrin; Fischer, Michael J.; Fleming, Thomas; Zimmermann, Katharina; Ivanovic-Burmazovic, Ivana; Nawroth, Peter P.; Bierhaus, Angelika; Reeh, Peter W.; Sauer, Susanne K.

    2012-01-01

    Neuropathic pain can develop as an agonizing sequela of diabetes mellitus and chronic uremia. A chemical link between both conditions of altered metabolism is the highly reactive compound methylglyoxal (MG), which accumulates in all cells, in particular neurons, and leaks into plasma as an index of the severity of the disorder. The electrophilic structure of this cytotoxic ketoaldehyde suggests TRPA1, a receptor channel deeply involved in inflammatory and neuropathic pain, as a molecular target. We demonstrate that extracellularly applied MG accesses specific intracellular binding sites of TRPA1, activating inward currents and calcium influx in transfected cells and sensory neurons, slowing conduction velocity in unmyelinated peripheral nerve fibers, and stimulating release of proinflammatory neuropeptides from and action potential firing in cutaneous nociceptors. Using a model peptide of the N terminus of human TRPA1, we demonstrate the formation of disulfide bonds based on MG-induced modification of cysteines as a novel mechanism. In conclusion, MG is proposed to be a candidate metabolite that causes neuropathic pain in metabolic disorders and thus is a promising target for medicinal chemistry. PMID:22740698

  20. Transient receptor potential ion channels in primary sensory neurons as targets for novel analgesics

    PubMed Central

    Sousa-Valente, J; Andreou, A P; Urban, L; Nagy, I

    2014-01-01

    The last decade has witnessed an explosion in novel findings relating to the molecules involved in mediating the sensation of pain in humans. Transient receptor potential (TRP) ion channels emerged as the greatest group of molecules involved in the transduction of various physical stimuli into neuronal signals in primary sensory neurons, as well as, in the development of pain. Here, we review the role of TRP ion channels in primary sensory neurons in the development of pain associated with peripheral pathologies and possible strategies to translate preclinical data into the development of effective new analgesics. Based on available evidence, we argue that nociception-related TRP channels on primary sensory neurons provide highly valuable targets for the development of novel analgesics and that, in order to reduce possible undesirable side effects, novel analgesics should prevent the translocation from the cytoplasm to the cell membrane and the sensitization of the channels rather than blocking the channel pore or binding sites for exogenous or endogenous activators. LINKED ARTICLES This article is part of a themed section on the pharmacology of TRP channels. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-10 PMID:24283624

  1. Role of oxidative stress & transient receptor potential in chronic obstructive pulmonary disease

    PubMed Central

    Bose, Protiti; Bathri, Rashmi; Kumar, Lalit; Vijayan, V.K.; Maudar, K.K.

    2015-01-01

    Chronic obstructive pulmonary disease (COPD) affect millions of people worldwide and is known to be one of the leading causes of death. The highly sensitive airways protect themselves from irritants by cough and sneeze which propel endogenous and exogenous substances to minimize airway noxious effects. One noxious effect of these substances is activation of peripheral sensory nerve endings of nociceptor neurons innervating these airways lining thus transmitting dangerous signals from the environment to the central nervous system (CNS). Nociceptor neurons include transient receptor potential (TRP) ion channels, especially the vanilloid and ankyrin subfamilies, TRPV1/A1 which can be activated by noxious chemical challenges in models of airways disease. As oxidative stress may activate airways sensory neurons and contribute to COPD exacerbations we sought to review the role that TRP channel activation by oxidative signals may have on airway responses. It would be prudent to target the TRP channels with antagonists and lower systemic oxidative stress with agents that can modulate TRP expression and boost the endogenous levels of antioxidants for treatment and management of COPD. PMID:26458340

  2. Upregulation of Transient Receptor Potential Canonical Channels Contributes to Endotoxin-Induced Pulmonary Arterial Stenosis

    PubMed Central

    Chen, Gui-Lan; Jiang, Hongni; Zou, Fangdong

    2016-01-01

    Background Septic shock is a pathologic condition caused by endotoxin-producing bacteria, and often associated with severe pulmonary hypertension. Inflammation is a major systemic response to endotoxin; however, it is unknown whether endotoxin has a direct impact on pulmonary arteries that contributes to pathogenesis of pulmonary hypertension. Material/Methods Rat pulmonary arteries and primary pulmonary arterial smooth muscle cells (PASMCs) were cultured in vitro and treated with lipopolysaccharide (LPS) and blockers of transient receptor potential canonical (TRPC) channels. Neointimal growth and arterial stenosis were observed on cryosections of cultured pulmonary arteries. Proliferation of PASMCs was examined by a WST-1 (water-soluble tetrazolium salt) assay. Expression of TRPC genes in pulmonary arteries and PASMCs were detected and quantified by real-time polymerase chain reaction and Western blotting. Results LPS significantly induced neointimal growth and stenosis of pulmonary arteries and promoted proliferation of PASMCs. TRPC channel blockers 2-aminoethoxydiphenyl borate and SKF-96365 inhibited LPS-induced remodeling of pulmonary arteries and PASMC proliferation. Expression of TRPC1/3/4/6 was detected in pulmonary arteries and PASMCs. LPS treatment dramatically increased the expression of TRPC3 and TRPC4 at both messenger RNA and protein levels. Conclusions LPS stimulates stenosis of pulmonary arteries through enhancement of TRPC-mediated Ca2+ entry into PASMCs, which is caused by upregulation of TRPC3 and TRPC4 channels. PMID:27471122

  3. The insect ecdysone receptor is a good potential target for RNAi-based pest control.

    PubMed

    Yu, Rong; Xu, Xinping; Liang, Yongkang; Tian, Honggang; Pan, Zhanqing; Jin, Shouheng; Wang, Na; Zhang, Wenqing

    2014-01-01

    RNA interference (RNAi) has great potential for use in insect pest control. However, some significant challenges must be overcome before RNAi-based pest control can become a reality. One challenge is the proper selection of a good target gene for RNAi. Here, we report that the insect ecdysone receptor (EcR) is a good potential target for RNAi-based pest control in the brown planthopper Nilaparvata lugens, a serious insect pest of rice plants. We demonstrated that the use of a 360 bp fragment (NlEcR-c) that is common between NlEcR-A and NlEcR-B for feeding RNAi experiments significantly decreased the relative mRNA expression levels of NlEcR compared with those in the dsGFP control. Feeding RNAi also resulted in a significant reduction in the number of offspring per pair of N. lugens. Consequently, a transgenic rice line expressing NlEcR dsRNA was constructed by Agrobacterium- mediated transformation. The results of qRT-PCR showed that the total copy number of the target gene in all transgenic rice lines was 2. Northern blot analysis showed that the small RNA of the hairpin dsNlEcR-c was successfully expressed in the transgenic rice lines. After newly hatched nymphs of N. lugens fed on the transgenic rice lines, effective RNAi was observed. The NlEcR expression levels in all lines examined were decreased significantly compared with the control. In all lines, the survival rate of the nymphs was nearly 90%, and the average number of offspring per pair in the treated groups was significantly less than that observed in the control, with a decrease of 44.18-66.27%. These findings support an RNAi-based pest control strategy and are also important for the management of rice insect pests.

  4. Vitamin D receptor expression is linked to potential markers of human thyroid papillary carcinoma.

    PubMed

    Izkhakov, Elena; Somjen, Dalia; Sharon, Orli; Knoll, Esther; Aizic, Asaf; Fliss, Dan M; Limor, Rona; Stern, Naftali

    2016-05-01

    Genes regulated cell-cell and cell-matrix adhesion and degradation of the extracellular matrix (ECM) have been screened as potential markers of malignant thyroid nodules. The mRNA expression levels of two of them, the ECM protein-1 (ECM1) and the type II transmembrane serine protease-4 (TMPRSS4), were shown to be an independent predictor of an existing thyroid carcinoma. The vitamin D receptor (VDR) is expressed in epithelial cells of the normal thyroid gland, as well as in malignant dividing cells, which respond to the active metabolite of vitamin D by decreased proliferative activity in vitro. We evaluated the relationship between mRNA gene expressions of TMPRSS4, ECM1 and VDR in 21 papillary thyroid carcinoma samples and compared it to 21 normal thyroid tissues from the same patients. Gene expression was considered as up- or down-regulated if it varied by more or less than 2-fold in the cancer tissue relative to the normal thyroid tissue (Ca/N) from the same patient. We found an overall significant adjusted correlation between the mRNA expression ratio (ExR) of VDR and that of ECM1 in Ca/N thyroid tissue (R=0.648, P<0.001). There was a high ExR of VDR between Ca/N thyroid tissue from the same patient (3.06±2.9), which also exhibited a high Ca/N ExR of ECM1 and/or of TMPRSS4 (>2, P=0.05).The finding that increased VDR expression in human thyroid cancer cells is often linked to increased ECM1 and/or TPMRSS4 expression warrants further investigation into the potential role of vitamin D analogs in thyroid carcinoma.

  5. The flavonoid baicalein promotes NMDA receptor-dependent long-term potentiation and enhances memory

    PubMed Central

    Wang, Wei; Wang, Fang; Yang, Yuan-Jian; Hu, Zhuang-Li; Long, Li-Hong; Fu, Hui; Xie, Na; Chen, Jian-Guo

    2011-01-01

    BACKGROUND AND PURPOSE There is growing interest in the physiological functions of flavonoids, especially in their effects on cognitive function and on neurodegenerative diseases. The aim of the current investigation was to evaluate the role of the flavonoid baicalein in long-term potentiation (LTP) in the hippocampal CA1 region and cognitive behavioural performance. EXPERIMENTAL APPROACH Effects of baicalein on LTP in rat hippocampal slices were investigated by electrophysiological methods. Phosphorylation of Akt (at Ser473), the extracellular signal-regulated kinase (ERK1/2) and the transcription factor cAMP response element-binding protein (CREB) (at Ser133) were analysed by Western blot. Fear conditioning was used to determine whether baicalein could improve learning and memory in rats. KEY RESULTS Baicalein enhanced the N-methyl-d-aspartate glutamate receptor-dependent LTP in a bell-shaped concentration-dependent manner. Addition of the lipoxygenase metabolites 12(S)-HETE and 12(S)-HPETE did not reverse these effects of baicalein. Baicalein treatment enhanced phosphorylation of Akt during induction of LTP with the same bell-shaped dose–response curve. LTP potentiation induced by baicalein was blocked by inhibitors of phosphoinositide 3-kinase. CREB phosphorylation was also increased in the CA1 region of baicalein-treated slices. Baicalein-treated rats performed significantly better than controls in a hippocampus-dependent contextual fear conditioning task. Furthermore, baicalein treatment selectively increased the phosphorylation of Akt and CREB in the CA1 region of hippocampus, but not in the prefrontal cortex, after fear conditioning training. CONCLUSIONS AND IMPLICATIONS Our results demonstrate that the flavonoid baicalein can facilitate memory, and therefore it might be useful in the treatment of patients with memory disorders. PMID:21133890

  6. The Insect Ecdysone Receptor is a Good Potential Target for RNAi-based Pest Control

    PubMed Central

    Yu, Rong; Xu, Xinping; Liang, Yongkang; Tian, Honggang; Pan, Zhanqing; Jin, Shouheng; Wang, Na; Zhang, Wenqing

    2014-01-01

    RNA interference (RNAi) has great potential for use in insect pest control. However, some significant challenges must be overcome before RNAi-based pest control can become a reality. One challenge is the proper selection of a good target gene for RNAi. Here, we report that the insect ecdysone receptor (EcR) is a good potential target for RNAi-based pest control in the brown planthopper Nilaparvata lugens, a serious insect pest of rice plants. We demonstrated that the use of a 360 bp fragment (NlEcR-c) that is common between NlEcR-A and NlEcR-B for feeding RNAi experiments significantly decreased the relative mRNA expression levels of NlEcR compared with those in the dsGFP control. Feeding RNAi also resulted in a significant reduction in the number of offspring per pair of N. lugens. Consequently, a transgenic rice line expressing NlEcR dsRNA was constructed by Agrobacterium- mediated transformation. The results of qRT-PCR showed that the total copy number of the target gene in all transgenic rice lines was 2. Northern blot analysis showed that the small RNA of the hairpin dsNlEcR-c was successfully expressed in the transgenic rice lines. After newly hatched nymphs of N. lugens fed on the transgenic rice lines, effective RNAi was observed. The NlEcR expression levels in all lines examined were decreased significantly compared with the control. In all lines, the survival rate of the nymphs was nearly 90%, and the average number of offspring per pair in the treated groups was significantly less than that observed in the control, with a decrease of 44.18-66.27%. These findings support an RNAi-based pest control strategy and are also important for the management of rice insect pests. PMID:25516715

  7. Inhibition of transient receptor potential canonical channels impairs cytokinesis in human malignant gliomas

    PubMed Central

    Bomben, V. C.; Sontheimer, H. W.

    2009-01-01

    Objectives Glial-derived primary brain tumours, gliomas, are among the fastest growing malignancies and present a huge clinical challenge. Research suggests an important, yet poorly understood, role of ion channels in growth control of normal and malignant cells. In this study, we sought to functionally characterize Transient Receptor Potential Canoncial (TRPC) channels in glioma cell proliferation. TRPC channels form non-selective cation channels that have been suggested to represent a Ca2+ influx pathway impacting cellular growth. Materials and Methods Employing a combination of molecular, biochemical and biophysical techniques, we characterized TRPC channels in glioma cells. Results We showed consistent expression of four channel family members (TRPC-1, -3, -5, -6) in glioma cell lines and acute patient-derived tissues. These channels gave rise to small, non-voltage-dependent cation currents that were blocked by the TRPC inhibitors GdCl3, 2-APB, or SKF96365. Importantly, TRPC channels contributed to the resting conductance of glioma cells and their acute pharmacological inhibition caused an ~10 mV hyperpolarization of the cells’ resting potential. Additionally, chronic application of the TRPC inhibitor SKF96365 caused near complete growth arrest. A detailed analysis, by fluorescence-activated cell sorting and time-lapse microscopy, showed that growth inhibition occurred at the G2 + M phase of the cell cycle with cytokinesis defects. Cells underwent incomplete cell divisions and became multinucleate, enlarged cells. Conclusions Nuclear atypia and enlarged cells are histopathological hallmarks for glioblastoma multiforme, the highest grade glioma, suggesting that a defect in TRPC channel function may contribute to cellular abnormalities in these tumours. PMID:18211288

  8. Receptor tyrosine kinase (c-Kit) inhibitors: a potential therapeutic target in cancer cells.

    PubMed

    Abbaspour Babaei, Maryam; Kamalidehghan, Behnam; Saleem, Mohammad; Huri, Hasniza Zaman; Ahmadipour, Fatemeh

    2016-01-01

    c-Kit, a receptor tyrosine kinase, is involved in intracellular signaling, and the mutated form of c-Kit plays a crucial role in occurrence of some cancers. The function of c-Kit has led to the concept that inhibiting c-Kit kinase activity can be a target for cancer therapy. The promising results of inhibition of c-Kit for treatment of cancers have been observed in some cancers such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors, and these results have encouraged attempts toward improvement of using c-Kit as a capable target for cancer therapy. This paper presents the findings of previous studies regarding c-Kit as a receptor tyrosine kinase and an oncogene, as well as its gene targets and signaling pathways in normal and cancer cells. The c-Kit gene location, protein structure, and the role of c-Kit in normal cell have been discussed. Comprehending the molecular mechanism underlying c-Kit-mediated tumorogenesis is consequently essential and may lead to the identification of future novel drug targets. The potential mechanisms by which c-Kit induces cellular transformation have been described. This study aims to elucidate the function of c-Kit for future cancer therapy. In addition, it has c-Kit inhibitor drug properties and their functions have been listed in tables and demonstrated in schematic pictures. This review also has collected previous studies that targeted c-Kit as a novel strategy for cancer therapy. This paper further emphasizes the advantages of this approach, as well as the limitations that must be addressed in the future. Finally, although c-Kit is an attractive target for cancer therapy, based on the outcomes of treatment of patients with c-Kit inhibitors, it is unlikely that Kit inhibitors alone can lead to cure. It seems that c-Kit mutations alone are not sufficient for tumorogenesis, but do play a crucial role in cancer occurrence. PMID:27536065

  9. Receptor tyrosine kinase (c-Kit) inhibitors: a potential therapeutic target in cancer cells

    PubMed Central

    Abbaspour Babaei, Maryam; Kamalidehghan, Behnam; Saleem, Mohammad; Huri, Hasniza Zaman; Ahmadipour, Fatemeh

    2016-01-01

    c-Kit, a receptor tyrosine kinase, is involved in intracellular signaling, and the mutated form of c-Kit plays a crucial role in occurrence of some cancers. The function of c-Kit has led to the concept that inhibiting c-Kit kinase activity can be a target for cancer therapy. The promising results of inhibition of c-Kit for treatment of cancers have been observed in some cancers such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors, and these results have encouraged attempts toward improvement of using c-Kit as a capable target for cancer therapy. This paper presents the findings of previous studies regarding c-Kit as a receptor tyrosine kinase and an oncogene, as well as its gene targets and signaling pathways in normal and cancer cells. The c-Kit gene location, protein structure, and the role of c-Kit in normal cell have been discussed. Comprehending the molecular mechanism underlying c-Kit-mediated tumorogenesis is consequently essential and may lead to the identification of future novel drug targets. The potential mechanisms by which c-Kit induces cellular transformation have been described. This study aims to elucidate the function of c-Kit for future cancer therapy. In addition, it has c-Kit inhibitor drug properties and their functions have been listed in tables and demonstrated in schematic pictures. This review also has collected previous studies that targeted c-Kit as a novel strategy for cancer therapy. This paper further emphasizes the advantages of this approach, as well as the limitations that must be addressed in the future. Finally, although c-Kit is an attractive target for cancer therapy, based on the outcomes of treatment of patients with c-Kit inhibitors, it is unlikely that Kit inhibitors alone can lead to cure. It seems that c-Kit mutations alone are not sufficient for tumorogenesis, but do play a crucial role in cancer occurrence. PMID:27536065

  10. Dopamine-2 receptor blockade potentiates the renal effects of nitric oxide inhibition in humans.

    PubMed

    Montanari, A; Tateo, E; Fasoli, E; Donatini, A; Cimolato, B; Perinotto, P; Dall'Aglio, P

    1998-01-01

    In eight young healthy subjects on a 240 mM Na diet mean arterial pressure (MAP), renal hemodynamics and renal handling of Na and exogenous Li were measured at baseline and during acute nitric oxide (NO) inhibition with 90-minute infusion of 3.0 microg/kg x min(-1) of N(G)-L-arginine methyl ester (L-NAME). The same experiment was repeated with infusion of 50 microg/kg x min(-1) of DA2 receptor blocker L-Sulpiride (L-SULP) alone and, finally, with simultaneous infusion of both L-NAME and L-SULP. L-SULP alone did not elicit any effect. L-NAME alone produced no changes in MAP from 0 to 45 minutes (P1) and a 6.6% increase at 45 to 90 minutes (P2) of infusion. Effective renal plasma flow (ERPF, PAH clearance) and glomerular filtration rate (GFR, inulin clearance) declined by 10.2% and 7.6%, respectively, in P1 and by 15.3% and 11.5% in P2. Filtration Fraction (FF) rose by 4.2% in P2. Calculated renal vascular resistance (RVR) increased by 13.0% to 25.6%. Fractional excretion of Na (FENa) and Li (FELi) fell by 20.0% and by 16.0%, respectively, in P1 and by 40.0% and 25.1% in P2. All these variations, except for MAP and GFR, were significantly greater during coinfusion of L-NAME and L-SULP. ERPF declined by 17.8% to 33.7%, FENa by 26.7% to 53.3%, FELi by 13.8% to 34.8%, while RVR rose by 22.5% to 59.1% and FF by 10.1% to 29.3%. The present data confirm that NO blockade with low-dose systemic infusion of L-NAME produces renal vasoconstriction, reduced GFR with slight increase in FF, and enhanced tubular Li, and Na reabsorption. Since increase in RVR and FF and decrease in FENa and FELi are markedly potentiated by the simultaneous infusion of DA2 blocker L-SULP, which exerts no effects by itself, we suggest that DA interactions between DA system at the level of DA2 receptors and basal NO production play a physiological role in the regulation of renal function in humans.

  11. Potential Involvement of P2 Receptors in the Pathological Processes of Hyperthyroidism: A Pilot Study.

    PubMed

    Hong, Wu; Li, Guodong; Nie, Yijun; Zou, Lifang; Zhang, Xi; Liu, Shuangmei; Li, Guilin; Xu, Hong; Zhang, Chun-Ping; Liang, Shangdong

    2016-05-01

    Symptoms of hyperthyroidism manifest mainly as changes in the nervous and metabolic systems. Whether P2X receptors (ionotropic ATP purinergic receptors, including P2X3 receptor and P2X7 receptor) are involved in the alterations of these disorders still remains unclear. Thus, this study aimed to assess the association of hyperthyroidism with the expression of P2X3 and P2X7 receptors and the concentrations of ATP in blood leukocytes and catecholamine. Twelve healthy subjects and twelve patients diagnosed with hyperthyroidism were recruited. Serum free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) levels had been detected by chemiluminescence method. Meanwhile, the catecholamine levels (including adrenaline, noradrenaline, and dopamine) in plasma, ATP level and P2X receptors (including P2X3 receptor and P2X7 receptor) in peripheral blood had been detected by high performance liquid chromatography, bioluminescence method, and reverse transcription polymerase chain reaction, respectively. Levels of epinephrine and norepinephrine were significantly higher in the hyperthyroidism group compared with the control group. The concentration of ATP in the hyperthyroidism group was significantly higher than its in the control group. The expression of P2X3 mRNA and P2X7 mRNA in hyperthyroidism group were significantly increased compared with those in control group. In a conclusion, there is a relationship between the elevated expression of P2X3 receptor and P2X7 receptor in peripheral blood leukocytes and high serum epinephrine and norepinephrine levels in hyperthyroidism patients. PMID:27312548

  12. Oncogenic Potential of the Nuclear Receptor Coregulator Proline-, Glutamic Acid–, Leucine-Rich Protein 1/Modulator of the Nongenomic Actions of the Estrogen Receptor

    PubMed Central

    Rajhans, Rajib; Nair, Sujit; Holden, Alan H.; Kumar, Rakesh; Tekmal, Rajeshwar Rao; Vadlamudi, Ratna K.

    2009-01-01

    Proline-, glutamic acid–, leucine-rich protein 1 (PELP1), a novel nuclear receptor coactivator, and its expression is deregulated in hormone-dependent cancers, including those of the breast, endometrium, and ovary. PELP1 interacts with estrogen receptor and modulates its genomic and nongenomic functions. In this study, we examined whether PELP1 functions as an oncogene. The overexpression of PELP1 in fibroblasts and epithelial model cells resulted in cellular transformation. PELP1 also enhanced the transformation potential of c-Src kinase in focus formation assays, and PELP1 overexpression potentiated estradiol-mediated cell migratory potential and anchorage-independent growth. Using PELP1-small interfering RNA, we provided evidence that endogenous PELP1 plays an essential role in E2-mediated anchorage-independent growth, cell migration, and cytoskeletal changes. When compared with control vector transfectants, breast cancer cells stably overexpressing PELP1 showed a rapid tumor growth in xenograft studies. Immunohistochemical analysis of PELP1 expression using a tumor progression array of 252 breast carcinomas and normal breast tissue specimens revealed that PELP1 expression is deregulated to a greater degree in higher grade node-positive invasive tumors than in normal breast tissue or ductal carcinoma in situ. Our data suggest that PELP1 is a potential oncogene, that its expression is deregulated during cancer progression, and that PELP1 may play a role in oncogenesis. PMID:17545633

  13. Eph receptor A10 has a potential as a target for a prostate cancer therapy

    SciTech Connect

    Nagano, Kazuya; Yamashita, Takuya; Inoue, Masaki; Higashisaka, Kazuma; Yoshioka, Yasuo; Abe, Yasuhiro; Kamada, Haruhiko; and others

    2014-07-18

    Highlights: • EphA10 mRNA is overexpressed in breast, prostate and colon cancer cell lines. • EphA10 is overexpressed in clinical prostate tumors at mRNA and protein levels. • Anti-EphA10 antibodies were cytotoxic on EphA10-positive prostate cancer cells. - Abstract: We recently identified Eph receptor A10 (EphA10) as a novel breast cancer-specific protein. Moreover, we also showed that an in-house developed anti-EphA10 monoclonal antibody (mAb) significantly inhibited proliferation of breast cancer cells, suggesting EphA10 as a promising target for breast cancer therapy. However, the only other known report for EphA10 was its expression in the testis at the mRNA level. Therefore, the potency of EphA10 as a drug target against cancers other than the breast is not known. The expression of EphA10 in a wide variety of cancer cells was studied and the potential of EphA10 as a drug target was evaluated. Screening of EphA10 mRNA expression showed that EphA10 was overexpressed in breast cancer cell lines as well as in prostate and colon cancer cell lines. Thus, we focused on prostate cancers in which EphA10 expression was equivalent to that in breast cancers. As a result, EphA10 expression was clearly shown in clinical prostate tumor tissues as well as in cell lines at the mRNA and protein levels. In order to evaluate the potential of EphA10 as a drug target, we analyzed complement-dependent cytotoxicity effects of anti-EphA10 mAb and found that significant cytotoxicity was mediated by the expression of EphA10. Therefore, the idea was conceived that the overexpression of EphA10 in prostate cancers might have a potential as a target for prostate cancer therapy, and formed the basis for the studies reported here.

  14. Menthol derivative WS-12 selectively activates transient receptor potential melastatin-8 (TRPM8) ion channels.

    PubMed

    Ma, Sherkheli; G, Gisselmann; Ak, Vogt-Eisele; Jf, Doerner; H, Hatt

    2008-10-01

    Transient receptor potential melastatin-8 (TRPM8), a cationic ion channel is involved in detection of normal cooling-sensation in mammals. TRPM8 activation by cooling or chemical agonists have been shown to produce profound, mechanistically novel analgesia in chronic pain states such as neuropathic pain in rodents. Known TRPM8 agonists such as menthol and icilin have a relatively low potency and cross-activate nociceptors like TRPA1; thus bearing a limited therapeutic usefulness. For that reason, characterising ligands, which selectively activate TRPM8, presents a clinical need. Using Xenopus laevis oocytes as expression system, we evaluated WS-12, a menthol derivative, for its potential interaction with all six thermo-sensitive TRP ion channels. Oocytes were injected with cRNA of gene of interest and incubated for 3-5 days (at 16 degrees C) before testing for functional characterisation of the recombinant ion channels. Oocytes were superfused with the test and standard substances respectively. Responses were measured by two-electrode voltage clamp technique and the amplitudes of evoked currents were compared with baseline values. WS-12 robustly activated TRPM8 in low micromolar concentrations (EC50 12+/-5 microM) thereby displaying a higher potency and efficacy compared to menthol (EC50 196+/-22 microM). Any of the other described thermo-sensitive TRP ion channel including TRPV1, TRPV2, TRPV3, TRPV4 and TRPA1 were not activated at a concentration (1 mM) optimally effective for TRPM8 responses; a characteristic which is in sharp contrast to menthol as it activates TRPA1 and TRPV3 in addition to TRPM8. Unlike icilin (75% reduction; p<0.001, n=6), WS-12 does not induce tachyphylaxis (4+/-2.3% increase in responses; p<0.08, n=6) of TRPM8 mediated currents to repeated exposure of 1 mM doses. In addition, acidosis or variations in extracellular calcium have no influence on potency/efficacy of WS-12 for TRPM8. The selectivity profile of WS-12, its several-fold higher

  15. Scavenger Receptors and Their Potential as Therapeutic Targets in the Treatment of Cardiovascular Disease

    PubMed Central

    Stephen, Sam L.; Freestone, Katie; Dunn, Sarah; Twigg, Michael W.; Homer-Vanniasinkam, Shervanthi; Walker, John H.; Wheatcroft, Stephen B.; Ponnambalam, Sreenivasan

    2010-01-01

    Scavenger receptors act as membrane-bound and soluble proteins that bind to macromolecular complexes and pathogens. This diverse supergroup of proteins mediates binding to modified lipoprotein particles which regulate the initiation and progression of atherosclerotic plaques. In vascular tissues, scavenger receptors are implicated in regulating intracellular signaling, lipid accumulation, foam cell development, and cellular apoptosis or necrosis linked to the pathophysiology of atherosclerosis. One approach is using gene therapy to modulate scavenger receptor function in atherosclerosis. Ectopic expression of membrane-bound scavenger receptors using viral vectors can modify lipid profiles and reduce the incidence of atherosclerosis. Alternatively, expression of soluble scavenger receptors can also block plaque initiation and progression. Inhibition of scavenger receptor expression using a combined gene therapy and RNA interference strategy also holds promise for long-term therapy. Here we review our current understanding of the gene delivery by viral vectors to cells and tissues in gene therapy strategies and its application to the modulation of scavenger receptor function in atherosclerosis. PMID:20981357

  16. Evaluation of Potential PET Imaging Probes for the Orexin 2 Receptors

    PubMed Central

    Wang, Changning; Wilson, Colin M.; Moseley, Christian K.; Carlin, Stephen M.; Hsu, Shirley; Arabasz, Grae; Schroeder, Frederick A.; Sander, Christin Y.; Hooker, Jacob M.

    2013-01-01

    A wide range of central nervous system (CNS) disorders, particularly those related to sleep, are associated with the abnormal function of orexin (OX) receptors. Several orexin receptor antagonists have been reported in recent years, but currently there are no imaging tools to probe the density and function of orexin receptors in vivo. To date there are no published data on the pharmacokinetics (PK) and accumulation of some lead orexin receptor antagonists. Evaluation of CNS pharmacokinetics in the pursuit of positron emission tomography (PET) radiotracer development could be used to elucidate the association of orexin receptors with diseases and to facilitate the drug discovery and development. To this end, we designed and evaluated carbon-11 labeled compounds based on diazepane orexin receptor antagonists previously described. One of the synthesized compounds, [11C]CW4 showed high brain uptake in rats and further evaluated in non-human primate (NHP) using PET-MR imaging. PET scans performed in a baboon showed appropriate early brain uptake for consideration as a radiotracer. However, [11C]CW4 exhibited fast kinetics and high nonspecific binding, as determined after co-administration of [11C]CW4 and unlabeled CW4. These properties indicate that [11C]CW4 has excellent brain penetrance and could be used as a lead compound for developing new CNS-penetrant PET imaging probes of orexin receptors. PMID:23953751

  17. Human eosinophils - potential pharmacological model applied in human histamine H4 receptor research.

    PubMed

    Grosicki, Marek; Kieć-Kononowicz, Katarzyna

    2015-01-01

    Histamine and histamine receptors are well known for their immunomodulatory role in inflammation. In this review we describe the role of histamine and histamine H4 receptor on human eosinophils. In the first part of article we provide short summary of histamine and histamine receptors role in physiology and histamine related therapeutics used in clinics. We briefly describe the human histamine receptor H4 and its ligands, as well as human eosinophils. In the second part of the review we provide detailed description of known histamine effects on eosinophils including: intracellular calcium concentration flux, actin polymerization, cellular shape change, upregulation of adhesion proteins and cellular chemotaxis. We provide proofs that these effects are mainly connected with the activation of histamine H4 receptor. When examining experimental data we discuss the controversial results and limitations of the studies performed on isolated eosinophils. In conclusion we believe that studies on histamine H4 receptor on human eosinophils can provide interesting new biomarkers that can be used in clinical studies of histamine receptors, that in future might result in the development of new strategies in the treatment of chronic inflammatory conditions like asthma or allergy, in which eosinophils are involved.

  18. Kappa-Opioid Receptor Signaling in the Striatum as a Potential Modulator of Dopamine Transmission in Cocaine Dependence

    PubMed Central

    Trifilieff, Pierre; Martinez, Diana

    2013-01-01

    Cocaine addiction is accompanied by a decrease in striatal dopamine signaling, measured as a decrease in dopamine D2 receptor binding as well as blunted dopamine release in the striatum. These alterations in dopamine transmission have clinical relevance, and have been shown to correlate with cocaine-seeking behavior and response to treatment for cocaine dependence. However, the mechanisms contributing to the hypodopaminergic state in cocaine addiction remain unknown. Here we review the positron emission tomography (PET) imaging studies showing alterations in D2 receptor binding potential and dopamine transmission in cocaine abusers and their significance in cocaine-seeking behavior. Based on animal and human studies, we propose that the kappa receptor/dynorphin system, because of its impact on dopamine transmission and upregulation following cocaine exposure, could contribute to the hypodopaminergic state reported in cocaine addiction, and could thus be a relevant target for treatment development. PMID:23760592

  19. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons

    PubMed Central

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation. PMID:27616980

  20. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons

    PubMed Central

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (IGABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited IGABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of IGABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation.

  1. Transient Receptor Potential Vanilloid 4 Inhibits γ-Aminobutyric Acid-Activated Current in Hippocampal Pyramidal Neurons.

    PubMed

    Hong, Zhiwen; Tian, Yujing; Qi, Mengwen; Li, Yingchun; Du, Yimei; Chen, Lei; Liu, Wentao; Chen, Ling

    2016-01-01

    The balance between excitatory and inhibitory neurotransmitter systems is crucial for the modulation of neuronal excitability in the central nervous system (CNS). The activation of transient receptor potential vanilloid 4 (TRPV4) is reported to enhance the response of hippocampal glutamate receptors, but whether the inhibitory neurotransmitter system can be regulated by TRPV4 remains unknown. γ-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the CNS. Here, we show that application of transient receptor potential vanilloid 4 (TRPV4) synthetic (GSK1016790A or 4α-PDD) or endogenous agonist (5,6-EET) inhibited GABA-activated current (I GABA) in hippocampal CA1 pyramidal neurons, which was blocked by specific antagonists of TRPV4 and of GABAA receptors. GSK1016790A increased the phosphorylated AMP-activated protein kinase (p-AMPK) and decreased the phosphorylated protein kinase B (p-Akt) protein levels, which was attenuated by removing extracellular calcium or by a calcium/calmodulin-dependent protein kinase kinase-β antagonist. GSK1016790A-induced decrease of p-Akt protein level was sensitive to an AMPK antagonist. GSK1016790A-inhibited I GABA was blocked by an AMPK antagonist or a phosphatidyl inositol 3 kinase (PI3K) agonist. GSK1016790A-induced inhibition of I GABA was also significantly attenuated by a protein kinase C (PKC) antagonist but was unaffected by protein kinase A or calcium/calmodulin-dependent protein kinase II antagonist. We conclude that activation of TRPV4 inhibits GABAA receptor, which may be mediated by activation of AMPK and subsequent down-regulation of PI3K/Akt signaling and activation of PKC signaling. Inhibition of GABAA receptors may account for the neuronal hyperexcitability caused by TRPV4 activation. PMID:27616980

  2. Enhanced cytotoxicity in triple-negative and estrogen receptor-positive breast adenocarcinoma cells due to inhibition of the transient receptor potential melastatin-2 channel

    PubMed Central

    KOH, DAVID W.; POWELL, DANIEL P.; BLAKE, STEVEN D.; HOFFMAN, JOY L.; HOPKINS, MANDI M.; FENG, XIAOXING

    2015-01-01

    We previously demonstrated a unique protective role for the transient receptor potential, melastatin-2 (TRPM2) cation channel in breast cancer cells. In the present study, we investigated the chemotherapeutic effects elicited by inhibiting this protective role in metastatic breast adenocarcinoma cells. TRPM2 inhibition led to dose-dependent increases in MDA-MB-231 breast adenocarcinoma cell death after treatment with doxorubicin or the DNA-methylating agent, N-methyl-N'-nitro-N-nitrosoguanidine. Similar results were observed after RNAi silencing of TRPM2 in these cells after doxorubicin treatment. However, TRPM2 RNAi silencing also led to increased MCF-7 breast adenocarcinoma cell death after tamoxifen treatment, yet not in non-cancerous human mammary epithelial cells. These results thus revealed that TRPM2 inhibition selectively increased cytotoxicity in a triple-negative and an estrogen receptor-positive breast cancer cell line, with minimal deleterious effects in non-cancerous breast cells. Analysis of DNA damage revealed enhanced DNA damage levels in MCF-7 cells treated with doxorubicin due to TRPM2 inhibition. Analysis of cell death demonstrated that inhibition of apoptosis, caspase-independent cell death or autophagy failed to significantly reduce cell death induced by TRPM2 inhibition and chemotherapy. These results indicate that TRPM2 inhibition activates alternative pathways of cell death in breast cancer cells. Taken together, our results provide significant evidence that TRPM2 inhibition is a potential strategy to induce triple-negative and estrogen receptor-positive breast adenocarcinoma cell death via alternative cell death pathways. This is expected to provide a basis for inhibiting TRPM2 for the improved treatment of breast cancer, which potentially includes treating breast tumors that are resistant to chemotherapy due to their evasion of apoptosis. PMID:26178079

  3. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer.

    PubMed

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-03-22

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  4. Activation of Transient Receptor Potential Ankyrin-1 by Insoluble Particulate Material and Association with Asthma.

    PubMed

    Deering-Rice, Cassandra E; Shapiro, Darien; Romero, Erin G; Stockmann, Chris; Bevans, Tatjana S; Phan, Quang M; Stone, Bryan L; Fassl, Bernhard; Nkoy, Flory; Uchida, Derek A; Ward, Robert M; Veranth, John M; Reilly, Christopher A

    2015-12-01

    Inhaled irritants activate transient receptor potential ankyrin-1 (TRPA1), resulting in cough, bronchoconstriction, and inflammation/edema. TRPA1 is also implicated in the pathogenesis of asthma. Our hypothesis was that particulate materials activate TRPA1 via a mechanism distinct from chemical agonists and that, in a cohort of children with asthma living in a location prone to high levels of air pollution, expression of uniquely sensitive forms of TRPA1 may correlate with reduced asthma control. Variant forms of TRPA1 were constructed by mutating residues in known functional elements and corresponding to single-nucleotide polymorphisms in functional domains. TRPA1 activity was studied in transfected HEK-293 cells using allyl-isothiocynate, a model soluble electrophilic agonist; 3,5-ditert butylphenol, a soluble nonelectrophilic agonist and a component of diesel exhaust particles; and insoluble coal fly ash (CFA) particles. The N-terminal variants R3C and R58T exhibited greater, but not additive, activity with all three agonists. The ankyrin repeat domain-4 single nucleotide polymorphisms E179K and K186N exhibited decreased response to CFA. The predicted N-linked glycosylation site residues N747A and N753A exhibited decreased responses to CFA, which were not attributable to differences in cellular localization. The pore-loop residue R919Q was comparable to wild-type, whereas N954T was inactive to soluble agonists but not CFA. These data identify roles for ankyrin domain-4, cell surface N-linked glycans, and selected pore-loop domain residues in the activation of TRPA1 by insoluble particles. Furthermore, the R3C and R58T polymorphisms correlated with reduced asthma control for some children, which suggest that TRPA1 activity may modulate asthma, particularly among individuals living in locations prone to high levels of air pollution.

  5. Temperature and voltage coupling to channel opening in transient receptor potential melastatin 8 (TRPM8).

    PubMed

    Raddatz, Natalia; Castillo, Juan P; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-12-19

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca(2+)-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol(-1). The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening. PMID:25352597

  6. Evidence for Novel Pharmacological Sensitivities of Transient Receptor Potential (TRP) Channels in Schistosoma mansoni

    PubMed Central

    Bais, Swarna; Churgin, Matthew A.; Fang-Yen, Christopher; Greenberg, Robert M.

    2015-01-01

    Schistosomiasis, caused by parasitic flatworms of the genus Schistosoma, is a neglected tropical disease affecting hundreds of millions globally. Praziquantel (PZQ), the only drug currently available for treatment and control, is largely ineffective against juvenile worms, and reports of PZQ resistance lend added urgency to the need for development of new therapeutics. Ion channels, which underlie electrical excitability in cells, are validated targets for many current anthelmintics. Transient receptor potential (TRP) channels are a large family of non-selective cation channels. TRP channels play key roles in sensory transduction and other critical functions, yet the properties of these channels have remained essentially unexplored in parasitic helminths. TRP channels fall into several (7–8) subfamilies, including TRPA and TRPV. Though schistosomes contain genes predicted to encode representatives of most of the TRP channel subfamilies, they do not appear to have genes for any TRPV channels. Nonetheless, we find that the TRPV1-selective activators capsaicin and resiniferatoxin (RTX) induce dramatic hyperactivity in adult worms; capsaicin also increases motility in schistosomula. SB 366719, a highly-selective TRPV1 antagonist, blocks the capsaicin-induced hyperactivity in adults. Mammalian TRPA1 is not activated by capsaicin, yet knockdown of the single predicted TRPA1-like gene (SmTRPA) in S. mansoni effectively abolishes capsaicin-induced responses in adult worms, suggesting that SmTRPA is required for capsaicin sensitivity in these parasites. Based on these results, we hypothesize that some schistosome TRP channels have novel pharmacological sensitivities that can be targeted to disrupt normal parasite neuromuscular function. These results also have implications for understanding the phylogeny of metazoan TRP channels and may help identify novel targets for new or repurposed therapeutics. PMID:26655809

  7. Potential role of A2A adenosine receptor in traumatic optic neuropathy.

    PubMed

    Ahmad, Saif; Fatteh, Nadeem; El-Sherbiny, Nehal M; Naime, Mohammad; Ibrahim, Ahmed S; El-Sherbini, Ahmed M; El-Shafey, Sally A; Khan, Sohail; Fulzele, Sadanand; Gonzales, Joyce; Liou, Gregory I

    2013-11-15

    In traumatic optic neuropathy (TON), apoptosis of retinal ganglion cells is closely related to the local production of reactive oxygen species and inflammatory mediators from activated microglial cells. Adenosine receptor A2A (A2AAR) has been shown to possess anti-inflammatory properties that have not been studied in TON. In the present study, we examined the role of A2AAR in retinal complications associated with TON. Initial studies in wild-type mice revealed that treatment with the A2AAR agonist resulted in marked decreases in the TON-induced microglial activation, retinal cell death and releases of reactive oxygen species and pro-inflammatory cytokines TNF-α and IL-6. To further assess the role of A2AAR in TON, we studied the effects of A2AAR ablation on the TON-induced retinal abnormalities. A2AAR-/- mice with TON showed a significantly higher mRNA level of TNF-α, Iba1-1 in retinal tissue, and ICAM-1 expression in retinal sections compared with wild-type mice with TON. To explore a potential mechanism by which A2AAR-signaling regulates inflammation in TON, we performed additional studies using hypoxia- or LPS-treated microglial cells as an in vitro model for TON. Activation of A2AAR attenuates hypoxia or LPS-induced TNF-α release and significantly repressed the inflammatory signaling, ERK in the activated microglia. Collectively, this work provides pharmacological and genetic evidence for A2AAR signaling as a control point of cell death in TON and suggests that the retinal protective effect of A2AAR is mediated by attenuating the inflammatory response that occurs in microglia via interaction with MAPKinase pathway.

  8. Transient Receptor Potential Ankyrin 1 Channel Involved in Atherosclerosis and Macrophage-Foam Cell Formation

    PubMed Central

    Zhao, Jin-Feng; Shyue, Song-Kun; Kou, Yu Ru; Lu, Tse-Min; Lee, Tzong-Shyuan

    2016-01-01

    Transient receptor potential ankyrin 1 channel (TRPA1) plays an important role in the pathogenesis of inflammatory diseases, yet its role and the underlying mechanism in atherosclerosis remain unclear. We aimed to investigate the role of TRPA1 in atherosclerosis and foam-cell formation in vivo in mice and in vitro in mouse macrophages. Histopathology was examined by hematoxylin and eosin staining, levels of cytokines and lipid profile were evaluated by assay kits, and protein expression was determined by western blot analysis. TRPA1 expression was increased in macrophage foam cells in atherosclerotic aortas of apolipoprotein E-deficient (apoE-/-) mice. Atherosclerotic lesions, hyperlipidemia and systemic inflammation were worsened with chronic administration of the TRPA1 channel antagonist HC030031 or genetic ablation of TRPA1 (TRPA1-/-) in apoE-/- mice. Treatment with allyl isothiocyanate (AITC, a TRPA1 agonist) retarded the progression of atherosclerosis in apoE-/- mice but not apoE-/-TRPA1-/- mice. Mouse macrophages showed oxidized low-density lipoprotein (oxLDL) activated TRPA1 channels. OxLDL-induced lipid accumulation of macrophages was exacerbated by HC030031 or loss of function of TRPA1. Inhibition of TRPA1 activity did not alter oxLDL internalization but impaired cholesterol efflux by downregulating the ATP-binding cassette transporters. Furthermore, tumor necrosis factor-α-induced inflammatory response was attenuated in AITC-activated macrophages. TRPA1 may be a pivotal regulator in the pathogenesis of atherosclerosis and cholesterol metabolism of macrophage foam cells. PMID:27313495

  9. Transient Receptor Potential Canonical Type 3 Channels Control the Vascular Contractility of Mouse Mesenteric Arteries

    PubMed Central

    Yeon, Soo-In; Kim, Joo Young; Yeon, Dong-Soo; Abramowitz, Joel; Birnbaumer, Lutz; Muallem, Shmuel; Lee, Young-Ho

    2014-01-01

    Transient receptor potential canonical type 3 (TRPC3) channels are non-selective cation channels and regulate intracellular Ca2+ concentration. We examined the role of TRPC3 channels in agonist-, membrane depolarization (high K+)-, and mechanical (pressure)-induced vasoconstriction and vasorelaxation in mouse mesenteric arteries. Vasoconstriction and vasorelaxation of endothelial cells intact mesenteric arteries were measured in TRPC3 wild-type (WT) and knockout (KO) mice. Calcium concentration ([Ca2+]) was measured in isolated arteries from TRPC3 WT and KO mice as well as in the mouse endothelial cell line bEnd.3. Nitric oxide (NO) production and nitrate/nitrite concentrations were also measured in TRPC3 WT and KO mice. Phenylephrine-induced vasoconstriction was reduced in TRPC3 KO mice when compared to that of WT mice, but neither high K+- nor pressure-induced vasoconstriction was altered in TRPC3 KO mice. Acetylcholine-induced vasorelaxation was inhibited in TRPC3 KO mice and by the selective TRPC3 blocker pyrazole-3. Acetylcholine blocked the phenylephrine-induced increase in Ca2+ ratio and then relaxation in TRPC3 WT mice but had little effect on those outcomes in KO mice. Acetylcholine evoked a Ca2+ increase in endothelial cells, which was inhibited by pyrazole-3. Acetylcholine induced increased NO release in TRPC3 WT mice, but not in KO mice. Acetylcholine also increased the nitrate/nitrite concentration in TRPC3 WT mice, but not in KO mice. The present study directly demonstrated that the TRPC3 channel is involved in agonist-induced vasoconstriction and plays important role in NO-mediated vasorelaxation of intact mesenteric arteries. PMID:25310225

  10. Temperature and voltage coupling to channel opening in transient receptor potential melastatin 8 (TRPM8).

    PubMed

    Raddatz, Natalia; Castillo, Juan P; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-12-19

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca(2+)-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol(-1). The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening.

  11. Transient receptor potential channel ankyrin-1 is not a cold sensor for autonomic thermoregulation in rodents.

    PubMed

    de Oliveira, Cristiane; Garami, Andras; Lehto, Sonya G; Pakai, Eszter; Tekus, Valeria; Pohoczky, Krisztina; Youngblood, Beth D; Wang, Weiya; Kort, Michael E; Kym, Philip R; Pinter, Erika; Gavva, Narender R; Romanovsky, Andrej A

    2014-03-26

    The rodent transient receptor potential ankyrin-1 (TRPA1) channel has been hypothesized to serve as a temperature sensor for thermoregulation in the cold. We tested this hypothesis by using deletion of the Trpa1 gene in mice and pharmacological blockade of the TRPA1 channel in rats. In both Trpa1(-/-) and Trpa1(+/+) mice, severe cold exposure (8°C) resulted in decreases of skin and deep body temperatures to ∼8°C and 13°C, respectively, both temperatures being below the reported 17°C threshold temperature for TRPA1 activation. Under these conditions, Trpa1(-/-) mice had the same dynamics of body temperature as Trpa1(+/+) mice and showed no weakness in the tail skin vasoconstriction response or thermogenic response to cold. In rats, the effects of pharmacological blockade were studied by using two chemically unrelated TRPA1 antagonists: the highly potent and selective compound A967079, which had been characterized earlier, and the relatively new compound 43 ((4R)-1,2,3,4-tetrahydro-4-[3-(3-methoxypropoxy)phenyl]-2-thioxo-5H-indeno[1,2-d]pyrimidin-5-one), which we further characterized in the present study and found to be highly potent (IC50 against cold of ∼8 nm) and selective. Intragastric administration of either antagonist at 30 mg/kg before severe (3°C) cold exposure did not affect the thermoregulatory responses (deep body and tail skin temperatures) of rats, even though plasma concentrations of both antagonists well exceeded their IC50 value at the end of the experiment. In the same experimental setup, blocking the melastatin-8 (TRPM8) channel with AMG2850 (30 mg/kg) attenuated cold-defense mechanisms and led to hypothermia. We conclude that TRPA1 channels do not drive autonomic thermoregulatory responses to cold in rodents.

  12. Noninvasive diode laser activation of transient receptor potential proteins and nociceptors

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Cooper, Brian Y.; Nemenov, Michael I.

    2007-02-01

    We investigated diode laser (980 nm) evoked activation of transient receptor potential proteins (TRPV1 and TRPV2). C and A-delta (Aδ) nociceptor families are primarily responsible for pain mediation in the peripheral nervous system. TRPV1 proteins have been associated with heat evoked pain in C fibers while Aδ fibers have been associated with TRPV2. Diode laser stimulation allows a margin of safety between non-invasive activation and damage 19, 22, 34. Laser pulses (20-50 ms, 0.1-10 W, 980 nm) were used to stimulate: A) in vitro: excised patches from HEK293 cells expressing TRPV1; B) in vitro: rat DRG nociceptors expressing either TRPV1 or TRPV2; and C) in vivo: C-fibers of the rat saphenous nerve (SN) trunk. Cell currents were recorded using standard patch clamp methods. The SN was also stimulated electrically with bipolar electrodes. Stimulation (20-50 ms) of HEK and DRG cells expressing TRPV1 was highly reproducible. Activation and peak currents were achieved at estimated peak temperatures of 55°C and 70°C. Threshold activation was also observed in DRG neurons expressing TRPV2. The conduction velocity for laser-activated saphenous nerve afferents was in the C fiber range (0.5-1 m/s). Electrically stimulated nerve contained stimulation artifacts and complex neural components with conduction velocities ranging from 0.3-30 m/s. Diode laser activation of TRPV1 protein is a reproducible and effective means to probe TRP activity in both in vivo and in vitro preparations

  13. Non-invasive diode laser activation of transient receptor potential proteins in nociceptors.

    PubMed

    Jiang, Nan; Cooper, Brian Y; Nemenov, Michael I

    2007-02-21

    We investigated diode laser (980 nm) evoked activation of transient receptor potential proteins (TRPV1 and TRPV2). C and A-delta (Aδ) nociceptor families are primarily responsible for pain mediation in the peripheral nervous system. TRPV1 proteins have been associated with heat evoked pain in C fibers while Aδ fibers have been associated with TRPV2. Diode laser stimulation allows a margin of safety between non-invasive activation and damage (19, 22, 34). Laser pulses (20-50 ms, 0.1-10 W, 980 nm) were used to stimulate: A) in vitro: excised patches from HEK293 cells expressing TRPV1; B) in vitro: rat DRG nociceptors expressing either TRPV1 or TRPV2; and C) in vivo: C-fibers of the rat saphenous nerve (SN) trunk. Cell currents were recorded using standard patch clamp methods. The SN was also stimulated electrically with bipolar electrodes. Stimulation (20-50 ms) of HEK and DRG cells expressing TRPV1 was highly reproducible. Activation and peak currents were achieved at estimated peak temperatures of 55°C and 70°C. Threshold activation was also observed in DRG neurons expressing TRPV2. The conduction velocity for laser-activated saphenous nerve afferents was in the C fiber range (0.5-1 m/s). Electrically stimulated nerve contained stimulation artifacts and complex neural components with conduction velocities ranging from 0.3-30 m/s. Diode laser activation of TRPV1 protein is a reproducible and effective means to probe TRP activity in both in vivo and in vitro preparations.

  14. Temperature and Voltage Coupling to Channel Opening in Transient Receptor Potential Melastatin 8 (TRPM8)*♦

    PubMed Central

    Raddatz, Natalia; Castillo, Juan P.; Gonzalez, Carlos; Alvarez, Osvaldo; Latorre, Ramon

    2014-01-01

    Expressed in somatosensory neurons of the dorsal root and trigeminal ganglion, the transient receptor potential melastatin 8 (TRPM8) channel is a Ca2+-permeable cation channel activated by cold, voltage, phosphatidylinositol 4,5-bisphosphate, and menthol. Although TRPM8 channel gating has been characterized at the single channel and macroscopic current levels, there is currently no consensus regarding the extent to which temperature and voltage sensors couple to the conduction gate. In this study, we extended the range of voltages where TRPM8-induced ionic currents were measured and made careful measurements of the maximum open probability the channel can attain at different temperatures by means of fluctuation analysis. The first direct measurements of TRPM8 channel temperature-driven conformational rearrangements provided here suggest that temperature alone is able to open the channel and that the opening reaction is voltage-independent. Voltage is a partial activator of TRPM8 channels, because absolute open probability values measured with fully activated voltage sensors are less than 1, and they decrease as temperature rises. By unveiling the fast temperature-dependent deactivation process, we show that TRPM8 channel deactivation is well described by a double exponential time course. The fast and slow deactivation processes are temperature-dependent with enthalpy changes of 27.2 and 30.8 kcal mol−1. The overall Q10 for the closing reaction is about 33. A three-tiered allosteric model containing four voltage sensors and four temperature sensors can account for the complex deactivation kinetics and coupling between voltage and temperature sensor activation and channel opening. PMID:25352597

  15. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer

    PubMed Central

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-01-01

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  16. Role of Transient Receptor Potential Vanilloid 4 in Neutrophil Activation and Acute Lung Injury.

    PubMed

    Yin, Jun; Michalick, Laura; Tang, Christine; Tabuchi, Arata; Goldenberg, Neil; Dan, Qinghong; Awwad, Khader; Wang, Liming; Erfinanda, Lasti; Nouailles, Geraldine; Witzenrath, Martin; Vogelzang, Alexis; Lv, Lu; Lee, Warren L; Zhang, Haibo; Rotstein, Ori; Kapus, Andras; Szaszi, Katalin; Fleming, Ingrid; Liedtke, Wolfgang B; Kuppe, Hermann; Kuebler, Wolfgang M

    2016-03-01

    The cation channel transient receptor potential vanilloid (TRPV) 4 is expressed in endothelial and immune cells; however, its role in acute lung injury (ALI) is unclear. The functional relevance of TRPV4 was assessed in vivo, in isolated murine lungs, and in isolated neutrophils. Genetic deficiency of TRPV4 attenuated the functional, histological, and inflammatory hallmarks of acid-induced ALI. Similar protection was obtained with prophylactic administration of the TRPV4 inhibitor, GSK2193874; however, therapeutic administration of the TRPV4 inhibitor, HC-067047, after ALI induction had no beneficial effect. In isolated lungs, platelet-activating factor (PAF) increased vascular permeability in lungs perfused with trpv4(+/+) more than with trpv4(-/-) blood, independent of lung genotype, suggesting a contribution of TRPV4 on blood cells to lung vascular barrier failure. In neutrophils, TRPV4 inhibition or deficiency attenuated the PAF-induced increase in intracellular calcium. PAF induced formation of epoxyeicosatrienoic acids by neutrophils, which, in turn, stimulated TRPV4-dependent Ca(2+) signaling, whereas inhibition of epoxyeicosatrienoic acid formation inhibited the Ca(2+) response to PAF. TRPV4 deficiency prevented neutrophil responses to proinflammatory stimuli, including the formation of reactive oxygen species, neutrophil adhesion, and chemotaxis, putatively due to reduced activation of Rac. In chimeric mice, however, the majority of protective effects in acid-induced ALI were attributable to genetic deficiency of TRPV4 in parenchymal tissue, whereas TRPV4 deficiency in circulating blood cells primarily reduced lung myeloperoxidase activity. Our findings identify TRPV4 as novel regulator of neutrophil activation and suggest contributions of both parenchymal and neutrophilic TRPV4 in the pathophysiology of ALI.

  17. Structural requirements of steroidal agonists of transient receptor potential melastatin 3 (TRPM3) cation channels

    PubMed Central

    Drews, A; Mohr, F; Rizun, O; Wagner, T F J; Dembla, S; Rudolph, S; Lambert, S; Konrad, M; Philipp, S E; Behrendt, M; Marchais-Oberwinkler, S; Covey, D F; Oberwinkler, J

    2014-01-01

    Background and Purpose Transient receptor potential melastatin 3 (TRPM3) proteins form non-selective but calcium-permeable membrane channels, rapidly activated by extracellular application of the steroid pregnenolone sulphate and the dihydropyridine nifedipine. Our aim was to characterize the steroid binding site by analysing the structural chemical requirements for TRPM3 activation. Experimental Approach Whole-cell patch-clamp recordings and measurements of intracellular calcium concentrations were performed on HEK293 cells transfected with TRPM3 (or untransfected controls) during superfusion with pharmacological substances. Key Results Pregnenolone sulphate and nifedipine activated TRPM3 channels supra-additively over a wide concentration range. Other dihydropyridines inhibited TRPM3 channels. The natural enantiomer of pregnenolone sulphate was more efficient in activating TRPM3 channels than its synthetic mirror image. However, both enantiomers exerted very similar inhibitory effects on proton-activated outwardly rectifying anion channels. Epiallopregnanolone sulphate activated TRPM3 almost equally as well as pregnenolone sulphate. Exchanging the sulphate for other chemical moieties showed that a negative charge at this position is required for activating TRPM3 channels. Conclusions and Implications Our data demonstrate that nifedipine and pregnenolone sulphate act at different binding sites when activating TRPM3. The latter activates TRPM3 by binding to a chiral and thus proteinaceous binding site, as inferred from the differential effects of the enantiomers. The double bond between position C5 and C6 of pregnenolone sulphate is not strictly necessary for the activation of TRPM3 channels, but a negative charge at position C3 of the steroid is highly important. These results provide a solid basis for understanding mechanistically the rapid chemical activation of TRPM3 channels. PMID:24251620

  18. Thermosensitive transient receptor potential channels (thermo-TRPs) in human corneal epithelial cells

    PubMed Central

    Mergler, Stefan; Garreis, Fabian; Sahlmüller, Monika; Reinach, Peter S.; Paulsen, Friedrich; Pleyer, Uwe

    2010-01-01

    Thermosensitive transient receptor potential proteins (TRPs) such as TRPV1-TRPV4 are all heat-activated non-selective cation channels that are modestly permeable to Ca2+. TRPV1, TRPV3 and TRPV4 functional expression were previously identified in human corneal epithelial cells (HCEC). However, the membrane currents were not described underlying their activation by either selective agonists or thermal variation. This study characterized the membrane currents and [Ca 2+]i transients induced by thermal and agonist TRPV1 and 4 stimulation. TRPV1 and 4 expressions were confirmed by RT-PCR and TRPV2 transcripts were also detected. In fura2-loaded HCEC, a TRPV1-3 selective agonist, 100 µM 2-aminoethoxydiphenyl borate (2-APB), induced intracellular Ca2+ transients and an increase in non-selective cation outward currents that were suppressed by ruthenium-red (RuR) (10–20 µM), a nonselective TRPV channel blocker. These changes were also elicited by rises in ambient temperature from 25 °C to over 40 °C. RuR (5 µM) and a selective TRPV1 channel blocker capsazepine (CPZ) (10 µM) or another related blocker, lanthanum chloride (La3+) (100 µM) suppressed these temperature-induced Ca2+ increases. Planar patch-clamp technique was used to characterize the currents underlying Ca2+ transients. Increasing the temperature to over 40 °C induced reversible rises in non-selective cation currents. Moreover, a hypotonic challenge (25 %) increased non-selective cation currents confirming TRPV4 activity. We conclude that HCEC possess in addition to thermo-sensitive TRPV3 activity TRPV1, TRPV2 and TRPV4 activity. Their activation confers temperature sensitivity at the ocular surface, which may protect the cornea against such stress. PMID:21506114

  19. Transient receptor potential ankyrin 1 mediates chronic pancreatitis pain in mice.

    PubMed

    Cattaruzza, Fiore; Johnson, Cali; Leggit, Alan; Grady, Eileen; Schenk, A Katrin; Cevikbas, Ferda; Cedron, Wendy; Bondada, Sandhya; Kirkwood, Rebekah; Malone, Brian; Steinhoff, Martin; Bunnett, Nigel; Kirkwood, Kimberly S

    2013-06-01

    Chronic pancreatitis (CP) is a devastating disease characterized by persistent and uncontrolled abdominal pain. Our lack of understanding is partially due to the lack of experimental models that mimic the human disease and also to the lack of validated behavioral measures of visceral pain. The ligand-gated cation channel transient receptor potential ankyrin 1 (TRPA1) mediates inflammation and pain in early experimental pancreatitis. It is unknown if TRPA1 causes fibrosis and sustained pancreatic pain. We induced CP by injecting the chemical agent trinitrobenzene sulfonic acid (TNBS), which causes severe acute pancreatitis, into the pancreatic duct of C57BL/6 trpa1(+/+) and trpa1(-/-) mice. Chronic inflammatory changes and pain behaviors were assessed after 2-3 wk. TNBS injection caused marked pancreatic fibrosis with increased collagen-staining intensity, atrophy, fatty replacement, monocyte infiltration, and pancreatic stellate cell activation, and these changes were reflected by increased histological damage scores. TNBS-injected animals showed mechanical hypersensitivity during von Frey filament probing of the abdomen, decreased daily voluntary wheel-running activity, and increased immobility scores during open-field testing. Pancreatic TNBS also reduced the threshold to hindpaw withdrawal to von Frey filament probing, suggesting central sensitization. Inflammatory changes and pain indexes were significantly reduced in trpa1(-/-) mice. In conclusion, we have characterized in mice a model of CP that resembles the human condition, with marked histological changes and behavioral measures of pain. We have demonstrated, using novel and objective pain measurements, that TRPA1 mediates inflammation and visceral hypersensitivity in CP and could be a therapeutic target for the treatment of sustained inflammatory abdominal pain. PMID:23558009

  20. Role of Transient Receptor Potential Vanilloid 4 in Neutrophil Activation and Acute Lung Injury.

    PubMed

    Yin, Jun; Michalick, Laura; Tang, Christine; Tabuchi, Arata; Goldenberg, Neil; Dan, Qinghong; Awwad, Khader; Wang, Liming; Erfinanda, Lasti; Nouailles, Geraldine; Witzenrath, Martin; Vogelzang, Alexis; Lv, Lu; Lee, Warren L; Zhang, Haibo; Rotstein, Ori; Kapus, Andras; Szaszi, Katalin; Fleming, Ingrid; Liedtke, Wolfgang B; Kuppe, Hermann; Kuebler, Wolfgang M

    2016-03-01

    The cation channel transient receptor potential vanilloid (TRPV) 4 is expressed in endothelial and immune cells; however, its role in acute lung injury (ALI) is unclear. The functional relevance of TRPV4 was assessed in vivo, in isolated murine lungs, and in isolated neutrophils. Genetic deficiency of TRPV4 attenuated the functional, histological, and inflammatory hallmarks of acid-induced ALI. Similar protection was obtained with prophylactic administration of the TRPV4 inhibitor, GSK2193874; however, therapeutic administration of the TRPV4 inhibitor, HC-067047, after ALI induction had no beneficial effect. In isolated lungs, platelet-activating factor (PAF) increased vascular permeability in lungs perfused with trpv4(+/+) more than with trpv4(-/-) blood, independent of lung genotype, suggesting a contribution of TRPV4 on blood cells to lung vascular barrier failure. In neutrophils, TRPV4 inhibition or deficiency attenuated the PAF-induced increase in intracellular calcium. PAF induced formation of epoxyeicosatrienoic acids by neutrophils, which, in turn, stimulated TRPV4-dependent Ca(2+) signaling, whereas inhibition of epoxyeicosatrienoic acid formation inhibited the Ca(2+) response to PAF. TRPV4 deficiency prevented neutrophil responses to proinflammatory stimuli, including the formation of reactive oxygen species, neutrophil adhesion, and chemotaxis, putatively due to reduced activation of Rac. In chimeric mice, however, the majority of protective effects in acid-induced ALI were attributable to genetic deficiency of TRPV4 in parenchymal tissue, whereas TRPV4 deficiency in circulating blood cells primarily reduced lung myeloperoxidase activity. Our findings identify TRPV4 as novel regulator of neutrophil activation and suggest contributions of both parenchymal and neutrophilic TRPV4 in the pathophysiology of ALI. PMID:26222277

  1. A fibrinogen-related protein identified from hepatopancreas of crayfish is a potential pattern recognition receptor.

    PubMed

    Chen, Qiming; Bai, Suhua; Dong, Chaohua

    2016-09-01

    Fibrinogen-related protein (FREP) family is a large group of proteins containing fibrinogen-like (FBG) domain and plays multiple physiological roles in animals. However, their immune functions in crayfish are not fully explored. In the present study, a novel fibrinogen-like protein (designated as PcFBN1) was identified and characterized from hepatopancreas of red swamp crayfish Procambarus clarkii. The cDNA sequence of PcFBN1 contains an open reading frame (ORF) of 1353 bp encoding a protein of 450 amino acids. Sequence and structural analysis indicated that PcFBN1 contains an FBG domain in C-terminal and a putative signal peptide of 19 amino acids in N-terminal. Semi-quantitative PCR revealed that the main expression of PcFBN1 was observed in hepatopancreas and hemocyte. Temporal expression analysis exhibited that PcFBN1 expression could be significantly induced by heat-killed Aeromonas hydrophila. Tissue distribution and temporal change of PcFBN1 suggested that PcFBN1 may be involved in immune responses of red swamp crayfish. Recombinant PcFBN1 protein binds and agglutinates both gram-negative bacteria Escherichia coli and gram-positive bacteria Micrococcus lysodeikticus. Moreover, binding and agglutination is Ca(2+) dependent. Further analysis indicated that PcFBN1 recognizes some acetyl group-containing substance LPS and PGN. RNAi experiment revealed that PcFBN1 is required for bacterial clearance and survival from A. hydrophila infection. Reduction of PcFBN1 expression significantly decreased the survival and enhanced the number of A. hydrophila in the hemolymph. These results indicated that PcFBN1 plays an important role in the innate immunity of red swamp crayfish as a potential pattern recognition receptor. PMID:27417229

  2. Interleukin 6 Receptor Is an Independent Prognostic Factor and a Potential Therapeutic Target of Ovarian Cancer

    PubMed Central

    Isobe, Aki; Sawada, Kenjiro; Kinose, Yasuto; Ohyagi-Hara, Chifumi; Nakatsuka, Erika; Makino, Hiroshi; Ogura, Tomonori; Mizuno, Tomoko; Suzuki, Noriko; Morii, Eiichi; Nakamura, Koji; Sawada, Ikuko; Toda, Aska; Hashimoto, Kae; Mabuchi, Seiji; Ohta, Tsuyoshi; Morishige, Ken-ichirou; Kurachi, Hirohisa; Kimura, Tadashi

    2015-01-01

    Ovarian cancer remains the most lethal gynecologic cancer and new targeted molecular therapies against this miserable disease continue to be challenging. In this study, we analyzed the expressional patterns of Interleukin-6 (IL-6) and its receptor (IL-6R) expression in ovarian cancer tissues, evaluated the impact of these expressions on clinical outcomes of patients, and found that a high-level of IL-6R expression but not IL-6 expression in cancer cells is an independent prognostic factor. In in vitro analyses using ovarian cell lines, while six (RMUG-S, RMG-1, OVISE, A2780, SKOV3ip1 and OVCAR-3) of seven overexpressed IL-6R compared with a primary normal ovarian surface epithelium, only two (RMG-1, OVISE) of seven cell lines overexpressed IL-6, suggesting that IL-6/IL-6R signaling exerts in a paracrine manner in certain types of ovarian cancer cells. Ovarian cancer ascites were collected from patients, and we found that primary CD11b+CD14+ cells, which were predominantly M2-polarized macrophages, are the major source of IL-6 production in an ovarian cancer microenvironment. When CD11b+CD14+ cells were co-cultured with cancer cells, both the invasion and the proliferation of cancer cells were robustly promoted and these promotions were almost completely inhibited by pretreatment with anti-IL-6R antibody (tocilizumab). The data presented herein suggest a rationale for anti-IL-6/IL-6R therapy to suppress the peritoneal spread of ovarian cancer, and represent evidence of the therapeutic potential of anti-IL-6R therapy for ovarian cancer treatment. PMID:25658637

  3. Interleukin 6 receptor is an independent prognostic factor and a potential therapeutic target of ovarian cancer.

    PubMed

    Isobe, Aki; Sawada, Kenjiro; Kinose, Yasuto; Ohyagi-Hara, Chifumi; Nakatsuka, Erika; Makino, Hiroshi; Ogura, Tomonori; Mizuno, Tomoko; Suzuki, Noriko; Morii, Eiichi; Nakamura, Koji; Sawada, Ikuko; Toda, Aska; Hashimoto, Kae; Mabuchi, Seiji; Ohta, Tsuyoshi; Morishige, Ken-ichirou; Kurachi, Hirohisa; Kimura, Tadashi

    2015-01-01

    Ovarian cancer remains the most lethal gynecologic cancer and new targeted molecular therapies against this miserable disease continue to be challenging. In this study, we analyzed the expressional patterns of Interleukin-6 (IL-6) and its receptor (IL-6R) expression in ovarian cancer tissues, evaluated the impact of these expressions on clinical outcomes of patients, and found that a high-level of IL-6R expression but not IL-6 expression in cancer cells is an independent prognostic factor. In in vitro analyses using ovarian cell lines, while six (RMUG-S, RMG-1, OVISE, A2780, SKOV3ip1 and OVCAR-3) of seven overexpressed IL-6R compared with a primary normal ovarian surface epithelium, only two (RMG-1, OVISE) of seven cell lines overexpressed IL-6, suggesting that IL-6/IL-6R signaling exerts in a paracrine manner in certain types of ovarian cancer cells. Ovarian cancer ascites were collected from patients, and we found that primary CD11b+CD14+ cells, which were predominantly M2-polarized macrophages, are the major source of IL-6 production in an ovarian cancer microenvironment. When CD11b+CD14+ cells were co-cultured with cancer cells, both the invasion and the proliferation of cancer cells were robustly promoted and these promotions were almost completely inhibited by pretreatment with anti-IL-6R antibody (tocilizumab). The data presented herein suggest a rationale for anti-IL-6/IL-6R therapy to suppress the peritoneal spread of ovarian cancer, and represent evidence of the therapeutic potential of anti-IL-6R therapy for ovarian cancer treatment. PMID:25658637

  4. Transient receptor potential ankyrin 1 mediates chronic pancreatitis pain in mice.

    PubMed

    Cattaruzza, Fiore; Johnson, Cali; Leggit, Alan; Grady, Eileen; Schenk, A Katrin; Cevikbas, Ferda; Cedron, Wendy; Bondada, Sandhya; Kirkwood, Rebekah; Malone, Brian; Steinhoff, Martin; Bunnett, Nigel; Kirkwood, Kimberly S

    2013-06-01

    Chronic pancreatitis (CP) is a devastating disease characterized by persistent and uncontrolled abdominal pain. Our lack of understanding is partially due to the lack of experimental models that mimic the human disease and also to the lack of validated behavioral measures of visceral pain. The ligand-gated cation channel transient receptor potential ankyrin 1 (TRPA1) mediates inflammation and pain in early experimental pancreatitis. It is unknown if TRPA1 causes fibrosis and sustained pancreatic pain. We induced CP by injecting the chemical agent trinitrobenzene sulfonic acid (TNBS), which causes severe acute pancreatitis, into the pancreatic duct of C57BL/6 trpa1(+/+) and trpa1(-/-) mice. Chronic inflammatory changes and pain behaviors were assessed after 2-3 wk. TNBS injection caused marked pancreatic fibrosis with increased collagen-staining intensity, atrophy, fatty replacement, monocyte infiltration, and pancreatic stellate cell activation, and these changes were reflected by increased histological damage scores. TNBS-injected animals showed mechanical hypersensitivity during von Frey filament probing of the abdomen, decreased daily voluntary wheel-running activity, and increased immobility scores during open-field testing. Pancreatic TNBS also reduced the threshold to hindpaw withdrawal to von Frey filament probing, suggesting central sensitization. Inflammatory changes and pain indexes were significantly reduced in trpa1(-/-) mice. In conclusion, we have characterized in mice a model of CP that resembles the human condition, with marked histological changes and behavioral measures of pain. We have demonstrated, using novel and objective pain measurements, that TRPA1 mediates inflammation and visceral hypersensitivity in CP and could be a therapeutic target for the treatment of sustained inflammatory abdominal pain.

  5. Transient receptor potential ankyrin 1 mediates chronic pancreatitis pain in mice

    PubMed Central

    Cattaruzza, Fiore; Johnson, Cali; Leggit, Alan; Grady, Eileen; Schenk, A. Katrin; Cevikbas, Ferda; Cedron, Wendy; Bondada, Sandhya; Kirkwood, Rebekah; Malone, Brian; Steinhoff, Martin; Bunnett, Nigel

    2013-01-01

    Chronic pancreatitis (CP) is a devastating disease characterized by persistent and uncontrolled abdominal pain. Our lack of understanding is partially due to the lack of experimental models that mimic the human disease and also to the lack of validated behavioral measures of visceral pain. The ligand-gated cation channel transient receptor potential ankyrin 1 (TRPA1) mediates inflammation and pain in early experimental pancreatitis. It is unknown if TRPA1 causes fibrosis and sustained pancreatic pain. We induced CP by injecting the chemical agent trinitrobenzene sulfonic acid (TNBS), which causes severe acute pancreatitis, into the pancreatic duct of C57BL/6 trpa1+/+ and trpa1-/- mice. Chronic inflammatory changes and pain behaviors were assessed after 2–3 wk. TNBS injection caused marked pancreatic fibrosis with increased collagen-staining intensity, atrophy, fatty replacement, monocyte infiltration, and pancreatic stellate cell activation, and these changes were reflected by increased histological damage scores. TNBS-injected animals showed mechanical hypersensitivity during von Frey filament probing of the abdomen, decreased daily voluntary wheel-running activity, and increased immobility scores during open-field testing. Pancreatic TNBS also reduced the threshold to hindpaw withdrawal to von Frey filament probing, suggesting central sensitization. Inflammatory changes and pain indexes were significantly reduced in trpa1-/- mice. In conclusion, we have characterized in mice a model of CP that resembles the human condition, with marked histological changes and behavioral measures of pain. We have demonstrated, using novel and objective pain measurements, that TRPA1 mediates inflammation and visceral hypersensitivity in CP and could be a therapeutic target for the treatment of sustained inflammatory abdominal pain. PMID:23558009

  6. G protein-coupled receptor signaling via Src kinase induces endogenous human transient receptor potential vanilloid type 6 (TRPV6) channel activation.

    PubMed

    Spehr, Jennifer; Gelis, Lian; Osterloh, Markus; Oberland, Sonja; Hatt, Hanns; Spehr, Marc; Neuhaus, Eva M

    2011-04-15

    Ca(2+) homeostasis plays a critical role in a variety of cellular processes. We showed previously that stimulation of the prostate-specific G protein-coupled receptor (PSGR) enhances cytosolic Ca(2+) and inhibits proliferation of prostate cells. Here, we analyzed the signaling mechanisms underlying the PSGR-mediated Ca(2+) increase. Using complementary molecular, biochemical, electrophysiological, and live-cell imaging techniques, we found that endogenous Ca(2+)-selective transient receptor potential vanilloid type 6 (TRPV6) channels are critically involved in the PSGR-induced Ca(2+) signal. Biophysical characterization of the current activated by PSGR stimulation revealed characteristic properties of TRPV6. The molecular identity of the involved channel was confirmed using RNA interference targeting TrpV6. TRPV6-mediated Ca(2+) influx depended on Src kinase activity. Src kinase activation occurred independently of G protein activation, presumably by direct interaction with PSGR. Taken together, we report that endogenous TRPV6 channels are activated downstream of a G protein-coupled receptor and present the first physiological characterization of these channels in situ. PMID:21349844

  7. Human Mu Opioid Receptor (OPRM1A118G) polymorphism is associated with brain mu- opioid receptor binding potential in smokers

    SciTech Connect

    Ray, R.; Logan, J.; Ray, R.; Ruparel, K.; Newberg, A.; Wileyto, E.P.; Loughead, J.W.; Divgi, C.; Blendy, J.A.; Logan, J.; Zubieta, J.-K.; Lerman, C.

    2011-04-15

    Evidence points to the endogenous opioid system, and the mu-opioid receptor (MOR) in particular, in mediating the rewarding effects of drugs of abuse, including nicotine. A single nucleotide polymorphism (SNP) in the human MOR gene (OPRM1 A118G) has been shown to alter receptor protein level in preclinical models and smoking behavior in humans. To clarify the underlying mechanisms for these associations, we conducted an in vivo investigation of the effects of OPRM1 A118G genotype on MOR binding potential (BP{sub ND} or receptor availability). Twenty-two smokers prescreened for genotype (12 A/A, 10 */G) completed two [{sup 11}C] carfentanil positron emission tomography (PET) imaging sessions following overnight abstinence and exposure to a nicotine-containing cigarette and a denicotinized cigarette. Independent of session, smokers homozygous for the wild-type OPRM1 A allele exhibited significantly higher levels of MOR BP{sub ND} than smokers carrying the G allele in bilateral amygdala, left thalamus, and left anterior cingulate cortex. Among G allele carriers, the extent of subjective reward difference (denicotinized versus nicotine cigarette) was associated significantly with MOR BP{sub ND} difference in right amygdala, caudate, anterior cingulate cortex, and thalamus. Future translational investigations can elucidate the role of MORs in nicotine addiction, which may lead to development of novel therapeutics.

  8. CC-chemokine receptors: a potential therapeutic target for Trypanosoma cruzi-elicited myocarditis.

    PubMed

    Marino, A P M P; Silva, A A; Santos, P V A; Pinto, L M O; Gazinelli, R T; Teixeira, M M; Lannes-Vieira, J

    2005-03-01

    The comprehension of the pathogenesis of Trypanosoma cruzi-elicited myocarditis is crucial to delineate new therapeutic strategies aiming to ameliorate the inflammation that leads to heart dysfunction, without hampering parasite control. The augmented expression of CCL5/RANTES and CCL3/MIP-1alpha, and their receptor CCR5, in the heart of T. cruzi-infected mice suggests a role for CC-chemokines and their receptors in the pathogenesis of T. cruzi-elicited myocarditis. Herein, we discuss our recent results using a CC-chemokine receptor inhibitor (Met-RANTES), showing the participation of CC-chemokines in T. cruzi infection and unraveling CC-chemokine receptors as an attractive therapeutic target for further evaluation in Chagas disease.

  9. LASSO-ing Potential Nuclear Receptor Agonists and Antagonists: A New Computational Method for Database Screening

    EPA Science Inventory

    Nuclear receptors (NRs) are important biological macromolecular transcription factors that are implicated in multiple biological pathways and may interact with other xenobiotics that are endocrine disruptors present in the environment. Examples of important NRs include the androg...

  10. The therapeutic potential of histamine receptor ligands in inflammatory bowel disease.

    PubMed

    Neumann, Detlef; Seifert, Roland

    2014-09-01

    In the intestine of patients suffering from inflammatory bowel disease concentrations of histamine are increased compared to healthy controls. Genetic ablation of histamine production in mice ameliorates the course of experimentally induced colitis. These observations and first pharmacological studies indicate a function of histamine in the pathogenesis of inflammatory bowel disease. However, a closer examination reveals that available data are highly heterogeneous, limiting the rational design of strategies addressing specific histamine receptor subtypes as possible target for pharmacological interaction. However, very recently first clinical data indicate that antagonism at the histamine receptor subtype H4 provides a beneficial effect in at least the skin. Here, we discuss the available data on histamine effects and histamine receptor subtype functions in inflammatory bowel disease with a special emphasis on the histamine H4-receptor.

  11. [Influence of GABA(C)-Receptor Antagonist on Formation of Evoked Potentials in Columns of the Rat Somatosensory Cortex].

    PubMed

    Matukhno, A E; Lysenko, L V; Andreeva, Y V; Sukhov, A G

    2015-01-01

    Microelectrode studies of evoked potentials (EP) in neuronal column of rats barrel cortex show activating action of selective GABA(C)-receptor antagonist 1,2,5,6-tetrahydropyridin-4-yl-methylphosphinic acid (TPMPA) mainly on secondary components of EP of supragranular afferent layers of column compared to the efferent infragranular layers. These data suggest localization of GABA(C)-receptors on pre- synaptic terminals of thalamo-cortical glutamatergic afferents and ascending apical dendrites of pyramidal cells. A blockade of GABA(C)-receptors with the selective antagonist TPM PA leads to dose-dependent afferent depolarization with development of presynaptic inhibition and suppression of primary components of EP GABA(C)-receptors blocker produces different effects on secondary components of EP in supragranular layers of the cortex caused by the development of neuronal after hyperpolarization followed by high-amplitude primary response and afterdepolarization followed by low-amplitude primary responses with subsequent activation of different voltage-gated channels and formation of different level of cortical direct current potential gradients.

  12. Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development

    PubMed Central

    Sharma, Charu; Sadek, Bassem; Goyal, Sameer N.; Sinha, Satyesh; Ojha, Shreesh

    2015-01-01

    The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2) which have been explored as potential therapeutic targets for drug discovery and development. Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ9-tetrahydrocannabinol mediates its action through CB1/CB2 receptors. However, these synthetic based Cannabis derived compounds are known to exert adverse psychiatric effect and have also been exploited for drug abuse. This encourages us to find out an alternative and safe drug with the least psychiatric adverse effects. In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems. Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative. The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics. PMID:26664449

  13. [Influence of GABA(C)-Receptor Antagonist on Formation of Evoked Potentials in Columns of the Rat Somatosensory Cortex].

    PubMed

    Matukhno, A E; Lysenko, L V; Andreeva, Y V; Sukhov, A G

    2015-01-01

    Microelectrode studies of evoked potentials (EP) in neuronal column of rats barrel cortex show activating action of selective GABA(C)-receptor antagonist 1,2,5,6-tetrahydropyridin-4-yl-methylphosphinic acid (TPMPA) mainly on secondary components of EP of supragranular afferent layers of column compared to the efferent infragranular layers. These data suggest localization of GABA(C)-receptors on pre- synaptic terminals of thalamo-cortical glutamatergic afferents and ascending apical dendrites of pyramidal cells. A blockade of GABA(C)-receptors with the selective antagonist TPM PA leads to dose-dependent afferent depolarization with development of presynaptic inhibition and suppression of primary components of EP GABA(C)-receptors blocker produces different effects on secondary components of EP in supragranular layers of the cortex caused by the development of neuronal after hyperpolarization followed by high-amplitude primary response and afterdepolarization followed by low-amplitude primary responses with subsequent activation of different voltage-gated channels and formation of different level of cortical direct current potential gradients. PMID:26841661

  14. Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development.

    PubMed

    Sharma, Charu; Sadek, Bassem; Goyal, Sameer N; Sinha, Satyesh; Kamal, Mohammad Amjad; Ojha, Shreesh

    2015-01-01

    The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2) which have been explored as potential therapeutic targets for drug discovery and development. Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ(9)-tetrahydrocannabinol mediates its action through CB1/CB2 receptors. However, these synthetic based Cannabis derived compounds are known to exert adverse psychiatric effect and have also been exploited for drug abuse. This encourages us to find out an alternative and safe drug with the least psychiatric adverse effects. In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems. Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative. The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics. PMID:26664449

  15. Small Molecules from Nature Targeting G-Protein Coupled Cannabinoid Receptors: Potential Leads for Drug Discovery and Development.

    PubMed

    Sharma, Charu; Sadek, Bassem; Goyal, Sameer N; Sinha, Satyesh; Kamal, Mohammad Amjad; Ojha, Shreesh

    2015-01-01

    The cannabinoid molecules are derived from Cannabis sativa plant which acts on the cannabinoid receptors types 1 and 2 (CB1 and CB2) which have been explored as potential therapeutic targets for drug discovery and development. Currently, there are numerous cannabinoid based synthetic drugs used in clinical practice like the popular ones such as nabilone, dronabinol, and Δ(9)-tetrahydrocannabinol mediates its action through CB1/CB2 receptors. However, these synthetic based Cannabis derived compounds are known to exert adverse psychiatric effect and have also been exploited for drug abuse. This encourages us to find out an alternative and safe drug with the least psychiatric adverse effects. In recent years, many phytocannabinoids have been isolated from plants other than Cannabis. Several studies have shown that these phytocannabinoids show affinity, potency, selectivity, and efficacy towards cannabinoid receptors and inhibit endocannabinoid metabolizing enzymes, thus reducing hyperactivity of endocannabinoid systems. Also, these naturally derived molecules possess the least adverse effects opposed to the synthetically derived cannabinoids. Therefore, the plant based cannabinoid molecules proved to be promising and emerging therapeutic alternative. The present review provides an overview of therapeutic potential of ligands and plants modulating cannabinoid receptors that may be of interest to pharmaceutical industry in search of new and safer drug discovery and development for future therapeutics.

  16. Memory recuperative potential of rifampicin in aluminum chloride-induced dementia: role of pregnane X receptors.

    PubMed

    Kaur, P; Sodhi, R K

    2015-03-12

    The present study has been designed to investigate the potential of rifampicin [Pregnane X receptors (PXR) agonist] in experimental dementia. Aluminum chloride (AlCl3) [100mg/kg, p.o. for 42days] was administered to Wistar rats (n=6) to induce dementia. Morris water maze (MWM) test was used to assess learning and memory and rota rod test was used to assess locomotor activity of the animals. A battery of biochemical tests and histopathological evaluation using hematoxylin and eosin (H&E) and Congo Red stains were performed at the end of the study. AlCl3-treated rats demonstrated impaired cognition and locomotor activity on MWM apparatus and rota rod test, respectively. These animals exhibited a significant rise in acetylcholinesterase (AChE) activity (138±3.6), thiobarbituric acid reactive species (TBARS) level (15±1.6), nitrite (56±2.4) level and myeloperoxidase (MPO) activity (4.1±0.9) along with decline in reduced glutathione (GSH) level (22±1.3) in comparison to the control group (p<0.05). Further the H&E and Congo Red-stained cerebral cortex sections of AlCl3-treated rats indicated severe neutrophilic infiltration and amyloid deposition. Rifampicin-treated AlCl3-rats exhibited significant attenuation in memory deficits, biochemical parameters like AChE activity (33±1.4), TBARS level (4.1±1.0), nitrite level (64±2.6), MPO activity (3.6±1.0) and GSH level (53±2.4) along with improved histopathological alterations and locomotor activity when compared with AlCl3-treated rats (p<0.05). Combined administration of ketoconazole (a PXR antagonist) and rifampicin to AlCl3-treated animals reversed the rifampicin-induced protective effects. Therefore the results obtained from the study indicate a defensive role of rifampicin in memory dysfunction which may probably be due to its anti-cholinesterase, anti-oxidative, anti-inflammatory and amyloid lowering effects. Moreover the study speculates the potential of PXR in the pathophysiology of dementia which is subject

  17. Mechanisms of activation of nucleus accumbens neurons by cocaine via sigma-1 receptor-inositol 1,4,5-trisphosphate-transient receptor potential canonical channel pathways.

    PubMed

    Barr, Jeffrey L; Deliu, Elena; Brailoiu, G Cristina; Zhao, Pingwei; Yan, Guang; Abood, Mary E; Unterwald, Ellen M; Brailoiu, Eugen

    2015-08-01

    Cocaine promotes addictive behavior primarily by blocking the dopamine transporter, thus increasing dopamine transmission in the nucleus accumbens (nAcc); however, additional mechanisms are continually emerging. Sigma-1 receptors (σ1Rs) are known targets for cocaine, yet the mechanisms underlying σ1R-mediated effects of cocaine are incompletely understood. The present study examined direct effects of cocaine on dissociated nAcc neurons expressing phosphatidylinositol-linked D1 receptors. Endoplasmic reticulum-located σ1Rs and inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) were targeted using intracellular microinjection. IP3 microinjection robustly elevated intracellular Ca(2+) concentration, [Ca(2+)]i. While cocaine alone was devoid of an effect, the IP3-induced response was σ1R-dependently enhanced by cocaine co-injection. Likewise, cocaine augmented the [Ca(2+)]i increase elicited by extracellularly applying an IP3-generating molecule (ATP), via σ1Rs. The cocaine-induced enhancement of the IP3/ATP-mediated Ca(2+) elevation occurred at pharmacologically relevant concentrations and was mediated by transient receptor potential canonical channels (TRPC). IP3 microinjection elicited a slight, transient depolarization, further converted to a greatly enhanced, prolonged response, by cocaine co-injection. The cocaine-triggered augmentation was σ1R-dependent, TRPC-mediated and contingent on [Ca(2+)]i elevation. ATP-induced depolarization was similarly enhanced by cocaine. Thus, we identify a novel mechanism by which cocaine promotes activation of D1-expressing nAcc neurons: enhancement of IP3R-mediated responses via σ1R activation at the endoplasmic reticulum, resulting in augmented Ca(2+) release and amplified depolarization due to subsequent stimulation of TRPC. In vivo, intra-accumbal blockade of σ1R or TRPC significantly diminished cocaine-induced hyperlocomotion and locomotor sensitization, endorsing a physio-pathological significance of the pathway

  18. Activation of Transient Receptor Potential Canonical 3 (TRPC3)-mediated Ca2+ Entry by A1 Adenosine Receptor in Cardiomyocytes Disturbs Atrioventricular Conduction*

    PubMed Central

    Sabourin, Jessica; Antigny, Fabrice; Robin, Elodie; Frieden, Maud; Raddatz, Eric

    2012-01-01

    Although the activation of the A1-subtype of the adenosine receptors (A1AR) is arrhythmogenic in the developing heart, little is known about the underlying downstream mechanisms. The aim of this study was to determine to what extent the transient receptor potential canonical (TRPC) channel 3, functioning as receptor-operated channel (ROC), contributes to the A1AR-induced conduction disturbances. Using embryonic atrial and ventricular myocytes obtained from 4-day-old chick embryos, we found that the specific activation of A1AR by CCPA induced sarcolemmal Ca2+ entry. However, A1AR stimulation did not induce Ca2+ release from the sarcoplasmic reticulum. Specific blockade of TRPC3 activity by Pyr3, by a dominant negative of TRPC3 construct, or inhibition of phospholipase Cs and PKCs strongly inhibited the A1AR-enhanced Ca2+ entry. Ca2+ entry through TRPC3 was activated by the 1,2-diacylglycerol (DAG) analog OAG via PKC-independent and -dependent mechanisms in atrial and ventricular myocytes, respectively. In parallel, inhibition of the atypical PKCζ by myristoylated PKCζ pseudosubstrate inhibitor significantly decreased the A1AR-enhanced Ca2+ entry in both types of myocytes. Additionally, electrocardiography showed that inhibition of TRPC3 channel suppressed transient A1AR-induced conduction disturbances in the embryonic heart. Our data showing that A1AR activation subtly mediates a proarrhythmic Ca2+ entry through TRPC3-encoded ROC by stimulating the phospholipase C/DAG/PKC cascade provide evidence for a novel pathway whereby Ca2+ entry and cardiac function are altered. Thus, the A1AR-TRPC3 axis may represent a potential therapeutic target. PMID:22692208

  19. Autotaxin and LPA receptors represent potential molecular targets for the radiosensitization of murine glioma through effects on tumor vasculature.

    PubMed

    Schleicher, Stephen M; Thotala, Dinesh K; Linkous, Amanda G; Hu, Rong; Leahy, Kathleen M; Yazlovitskaya, Eugenia M; Hallahan, Dennis E

    2011-01-01

    Despite wide margins and high dose irradiation, unresectable malignant glioma (MG) is less responsive to radiation and is uniformly fatal. We previously found that cytosolic phospholipase A2 (cPLA(2)) is a molecular target for radiosensitizing cancer through the vascular endothelium. Autotaxin (ATX) and lysophosphatidic acid (LPA) receptors are downstream from cPLA(2) and highly expressed in MG. Using the ATX and LPA receptor inhibitor, α-bromomethylene phosphonate LPA (BrP-LPA), we studied ATX and LPA receptors as potential molecular targets for the radiosensitization of tumor vasculature in MG. Treatment of Human Umbilical Endothelial cells (HUVEC) and mouse brain microvascular cells bEND.3 with 5 µmol/L BrP-LPA and 3 Gy irradiation showed decreased clonogenic survival, tubule formation, and migration. Exogenous addition of LPA showed radioprotection that was abrogated in the presence of BrP-LPA. In co-culture experiments using bEND.3 and mouse GL-261 glioma cells, treatment with BrP-LPA reduced Akt phosphorylation in both irradiated cell lines and decreased survival and migration of irradiated GL-261 cells. Using siRNA to knock down LPA receptors LPA1, LPA2 or LPA3 in HUVEC, we demonstrated that knockdown of LPA2 but neither LPA1 nor LPA3 led to increased viability and proliferation. However, knockdown of LPA1 and LPA3 but not LPA2 resulted in complete abrogation of tubule formation implying that LPA1 and LPA3 on endothelial cells are likely targets of BrP-LPA radiosensitizing effect. Using heterotopic tumor models of GL-261, mice treated with BrP-LPA and irradiation showed a tumor growth delay of 6.8 days compared to mice treated with irradiation alone indicating that inhibition of ATX and LPA receptors may significantly improve malignant glioma response to radiation therapy. These findings identify ATX and LPA receptors as molecular targets for the development of radiosensitizers for MG.

  20. Potential involvement of P2Y2 receptor in diuresis of postobstructive uropathy in rats.

    PubMed

    Zhang, Yue; Kohan, Donald E; Nelson, Raoul D; Carlson, Noel G; Kishore, Bellamkonda K

    2010-03-01

    AVP resistance of the medullary collecting duct (mCD) in postobstructive uropathy (POU) has been attributed to increased production of PGE2. P2Y2 receptor activation causes production of PGE2 by the mCD. We hypothesize that increased P2Y2 receptor expression and/or activity may contribute to the diuresis of POU. Sprague-Dawley rats were subjected to bilateral ureteral obstruction for 24 h followed by release (BUO/R, n = 17) or sham operation (SHM/O, n = 15) and euthanized after 1 wk or 12 days. BUO/R rats developed significant polydipsia, polyuria, urinary concentration defect, and increased urinary PGE2 and decreased aquaporin-2 protein abundance in the inner medulla compared with SHM/O rats. After BUO/R, the relative mRNA expression of P2Y2 and P2Y6 receptors was increased by 2.7- and 4.9-fold, respectively, without significant changes in mRNA expression of P2Y1 or P2Y4 receptor. This was associated with a significant 3.5-fold higher protein abundance of the P2Y2 receptor in BUO/R than SHM/O rats. When freshly isolated mCD fractions were challenged with different types of nucleotides (ATPgammaS, ADP, UTP, or UDP), BUO/R and SHM/O rats responded to only ATPgammaS and UTP and released PGE2, consistent with involvement of the P2Y2, but not P2Y6, receptor. ATPgammaS- or UTP-stimulated increases in PGE2 were much higher in BUO/R (3.20- and 2.28-fold, respectively, vs. vehicle controls) than SHM/O (1.68- and 1.30-fold, respectively, vs. vehicle controls) rats. In addition, there were significant 2.4- and 2.1-fold increases in relative mRNA expression of prostanoid EP1 and EP3 receptors, respectively, in the inner medulla of BUO/R vs. SHM/O rats. Taken together, these data suggest that increased production of PGE2 by the mCD in POU may be due to increased expression and activity of the P2Y2 receptor. Increased mRNA expression of EP1 and EP3 receptors in POU may also help accentuate PGE2-induced signaling in the mCD.

  1. Lactate Transport and Receptor Actions in Retina: Potential Roles in Retinal Function and Disease.

    PubMed

    Kolko, Miriam; Vosborg, Fia; Henriksen, Ulrik L; Hasan-Olive, Md Mahdi; Diget, Elisabeth Holm; Vohra, Rupali; Gurubaran, Iswariya Raja Sridevi; Gjedde, Albert; Mariga, Shelton Tendai; Skytt, Dorte M; Utheim, Tor Paaske; Storm-Mathisen, Jon; Bergersen, Linda H

    2016-06-01

    In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions, such as excitability, metabolism and inflammation. Recent publications predict effects of the lactate receptor on neurodegeneration. Neurodegenerative diseases in retina, where the retinal ganglion cells die, notably glaucoma and diabetic retinopathy, may be linked to disturbed lactate homeostasis. Pilot studies reveal high GPR81 mRNA in retina and indicate GPR81 localization in Müller cells and retinal ganglion cells. Moreover, monocarboxylate transporters are expressed in retinal cells. We envision that lactate receptors and transporters could be useful future targets of novel therapeutic strategies to protect neurons and prevent or counteract glaucoma as well as other retinal diseases. PMID:26677077

  2. Immunoglobulin Transporting Receptors Are Potential Targets for the Immunity Enhancement and Generation of Mammary Gland Bioreactor

    PubMed Central

    Jiang, Xuemei; Hu, Jianjun; Thirumalai, Diraviyam; Zhang, Xiaoying

    2016-01-01

    The functions of immunoglobulin transporting receptors (Ig transporting receptors) in immune system encompass from passive immunity to adaptive immunity by transporting immunoglobulins (Igs) and prolonging their half-life as well as enhancing immunosurveillance. Prior to the weaning, Ig transportations from mother to offspring confer the immediate passive immunity for neonates. After the weaning, FcRn and polymeric immunoglobulin receptor on infant intestinal epithelial cells retrieve Ig in intestinal lamina propria into the gut lumen for preventing pathogen invasion. This is not only improving the pathological consequences of infection but also helping the neonates for developing their own immune response; besides it would be the guidance for designing novel vaccines. Moreover, the investigations on Ig transporting receptors over-expressed transgenic animals have been carried out to improve Ig concentrations in serum and milk; thus, it would be a sustainable method to produce antibody-enriched milk-derived colostrum replacer for neonates. In order to generate mammary gland bioreactor, a series of methods have been developed for enhanced regulation of Ig transporting receptors expression and Ig transportation. PMID:27375616

  3. Dopamine D3 Receptor Antagonists as Potential Therapeutics for the Treatment of Neurological Diseases

    PubMed Central

    Maramai, Samuele; Gemma, Sandra; Brogi, Simone; Campiani, Giuseppe; Butini, Stefania; Stark, Holger; Brindisi, Margherita

    2016-01-01

    D3 receptors represent a major focus of current drug design and development of therapeutics for dopamine-related pathological states. Their close homology with the D2 receptor subtype makes the development of D3 selective antagonists a challenging task. In this review, we explore the relevance and therapeutic utility of D3 antagonists or partial agonists endowed with multireceptor affinity profile in the field of central nervous system disorders such as schizophrenia and drug abuse. In fact, the peculiar distribution and low brain abundance of D3 receptors make them a valuable target for the development of drugs devoid of motor side effects classically elicited by D2 antagonists. Recent research efforts were devoted to the conception of chemical templates possibly endowed with a multi-target profile, especially with regards to other G-protein-coupled receptors (GPCRs). A comprehensive overview of the recent literature in the field is herein provided. In particular, the evolution of the chemical templates has been tracked, according to the growing advancements in both the structural information and the refinement of the key pharmacophoric elements. The receptor/multireceptor affinity and functional profiles for the examined compounds have been covered, together with their most significant pharmacological applications. PMID:27761108

  4. Allosteric Modulation of Metabotropic Glutamate Receptors: Structural Insights and Therapeutic Potential

    PubMed Central

    Gregory, Karen J.; Dong, Elizabeth N.; Meiler, Jens; Conn, P. Jeffrey

    2010-01-01

    Allosteric modulation of G protein-coupled receptors (GPCRs) represents a novel approach to the development of probes and therapeutics that is expected to enable subtype-specific regulation of central nervous system target receptors. The metabotropic glutamate receptors (mGlus) are class C GPCRs that play important neuromodulatory roles throughout the brain, as such they are attractive targets for therapeutic intervention for a number of psychiatric and neurological disorders including anxiety, depression, Fragile X Syndrome, Parkinson’s disease and schizophrenia. Over the last fifteen years, selective allosteric modulators have been identified for many members of the mGlu family. The vast majority of these allosteric modulators are thought to bind within the transmembrane-spanning domains of the receptors to enhance or inhibit functional responses. A combination of mutagenesis-based studies and pharmacological approaches are beginning to provide a better understanding of mGlu allosteric sites. Collectively, when mapped onto a homology model of the different mGlu subtypes based on the β2-adrenergic receptor, the previous mutagenesis studies suggest commonalities in the location of allosteric sites across different members of the mGlu family. In addition, there is evidence for multiple allosteric binding pockets within the transmembrane region that can interact to modulate one another. In the absence of a class C GPCR crystal structure, this approach has shown promise with respect to the interpretation of mutagenesis data and understanding structure-activity relationships of allosteric modulator pharmacophores. PMID:20637216

  5. Immunoglobulin Transporting Receptors Are Potential Targets for the Immunity Enhancement and Generation of Mammary Gland Bioreactor.

    PubMed

    Jiang, Xuemei; Hu, Jianjun; Thirumalai, Diraviyam; Zhang, Xiaoying

    2016-01-01

    The functions of immunoglobulin transporting receptors (Ig transporting receptors) in immune system encompass from passive immunity to adaptive immunity by transporting immunoglobulins (Igs) and prolonging their half-life as well as enhancing immunosurveillance. Prior to the weaning, Ig transportations from mother to offspring confer the immediate passive immunity for neonates. After the weaning, FcRn and polymeric immunoglobulin receptor on infant intestinal epithelial cells retrieve Ig in intestinal lamina propria into the gut lumen for preventing pathogen invasion. This is not only improving the pathological consequences of infection but also helping the neonates for developing their own immune response; besides it would be the guidance for designing novel vaccines. Moreover, the investigations on Ig transporting receptors over-expressed transgenic animals have been carried out to improve Ig concentrations in serum and milk; thus, it would be a sustainable method to produce antibody-enriched milk-derived colostrum replacer for neonates. In order to generate mammary gland bioreactor, a series of methods have been developed for enhanced regulation of Ig transporting receptors expression and Ig transportation. PMID:27375616

  6. Lactate Transport and Receptor Actions in Retina: Potential Roles in Retinal Function and Disease.

    PubMed

    Kolko, Miriam; Vosborg, Fia; Henriksen, Ulrik L; Hasan-Olive, Md Mahdi; Diget, Elisabeth Holm; Vohra, Rupali; Gurubaran, Iswariya Raja Sridevi; Gjedde, Albert; Mariga, Shelton Tendai; Skytt, Dorte M; Utheim, Tor Paaske; Storm-Mathisen, Jon; Bergersen, Linda H

    2016-06-01

    In retina, like in brain, lactate equilibrates across cell membranes via monocarboxylate transporters and in the extracellular space by diffusion, forming a basis for the action of lactate as a transmitter of metabolic signals. In the present paper, we argue that the lactate receptor GPR81, also known as HCAR1, may contribute importantly to the control of retinal cell functions in health and disease. GPR81, a G-protein coupled receptor, is known to downregulate cAMP both in adipose and nervous tissue. The receptor also acts through other down-stream mechanisms to control functions, such as excitability, metabolism and inflammation. Recent publications predict effects of the lactate receptor on neurodegeneration. Neurodegenerative diseases in retina, where the retinal ganglion cells die, notably glaucoma and diabetic retinopathy, may be linked to disturbed lactate homeostasis. Pilot studies reveal high GPR81 mRNA in retina and indicate GPR81 localization in Müller cells and retinal ganglion cells. Moreover, monocarboxylate transporters are expressed in retinal cells. We envision that lactate receptors and transporters could be useful future targets of novel therapeutic strategies to protect neurons and prevent or counteract glaucoma as well as other retinal diseases.

  7. Neutrophil Elastase Activates Protease-activated Receptor-2 (PAR2) and Transient Receptor Potential Vanilloid 4 (TRPV4) to Cause Inflammation and Pain*

    PubMed Central

    Zhao, Peishen; Lieu, TinaMarie; Barlow, Nicholas; Sostegni, Silvia; Haerteis, Silke; Korbmacher, Christoph; Liedtke, Wolfgang; Jimenez-Vargas, Nestor N.; Vanner, Stephen J.; Bunnett, Nigel W.

    2015-01-01

    Proteases that cleave protease-activated receptor-2 (PAR2) at Arg36↓Ser37 reveal a tethered ligand that binds to the cleaved receptor. PAR2 activates transient receptor potential (TRP) channels of nociceptive neurons to induce neurogenic inflammation and pain. Although proteases that cleave PAR2 at non-canonical sites can trigger distinct signaling cascades, the functional importance of the PAR2-biased agonism is uncertain. We investigated whether neutrophil elastase, a biased agonist of PAR2, causes inflammation and pain by activating PAR2 and TRP vanilloid 4 (TRPV4). Elastase cleaved human PAR2 at Ala66↓Ser67 and Ser67↓Val68. Elastase stimulated PAR2-dependent cAMP accumulation and ERK1/2 activation, but not Ca2+ mobilization, in KNRK cells. Elastase induced PAR2 coupling to Gαs but not Gαq in HEK293 cells. Although elastase did not promote recruitment of G protein-coupled receptor kinase-2 (GRK2) or β-arrestin to PAR2, consistent with its inability to promote receptor endocytosis, elastase did stimulate GRK6 recruitment. Elastase caused PAR2-dependent sensitization of TRPV4 currents in Xenopus laevis oocytes by adenylyl cyclase- and protein kinase A (PKA)-dependent mechanisms. Elastase stimulated PAR2-dependent cAMP formation and ERK1/2 phosphorylation, and a PAR2- and TRPV4-mediated influx of extracellular Ca2+ in mouse nociceptors. Adenylyl cyclase and PKA-mediated elastase-induced activation of TRPV4 and hyperexcitability of nociceptors. Intraplantar injection of elastase to mice caused edema and mechanical hyperalgesia by PAR2- and TRPV4-mediated mechanisms. Thus, the elastase-biased agonism of PAR2 causes Gαs-dependent activation of adenylyl cyclase and PKA, which activates TRPV4 and sensitizes nociceptors to cause inflammation and pain. Our results identify a novel mechanism of elastase-induced activation of TRPV4 and expand the role of PAR2 as a mediator of protease-driven inflammation and pain. PMID:25878251

  8. Transient Receptor Potential Melastatin 7 Cation Channel Kinase: New Player in Angiotensin II-Induced Hypertension.

    PubMed

    Antunes, Tayze T; Callera, Glaucia E; He, Ying; Yogi, Alvaro; Ryazanov, Alexey G; Ryazanova, Lillia V; Zhai, Alexander; Stewart, Duncan J; Shrier, Alvin; Touyz, Rhian M

    2016-04-01

    Transient receptor potential melastatin 7 (TRPM7) is a bifunctional protein comprising a magnesium (Mg(2+))/cation channel and a kinase domain. We previously demonstrated that vasoactive agents regulate vascular TRPM7. Whether TRPM7 plays a role in the pathophysiology of hypertension and associated cardiovascular dysfunction is unknown. We studied TRPM7 kinase-deficient mice (TRPM7Δkinase; heterozygous for TRPM7 kinase) and wild-type (WT) mice infused with angiotensin II (Ang II; 400 ng/kg per minute, 4 weeks). TRPM7 kinase expression was lower in heart and aorta from TRPM7Δkinase versus WT mice, effects that were further reduced by Ang II infusion. Plasma Mg(2+) was lower in TRPM7Δkinase versus WT mice in basal and stimulated conditions. Ang II increased blood pressure in both strains with exaggerated responses in TRPM7Δkinase versus WT groups (P<0.05). Acetylcholine-induced vasorelaxation was reduced in Ang II-infused TRPM7Δkinase mice, an effect associated with Akt and endothelial nitric oxide synthase downregulation. Vascular cell adhesion molecule-1 expression was increased in Ang II-infused TRPM7 kinase-deficient mice. TRPM7 kinase targets, calpain, and annexin-1, were activated by Ang II in WT but not in TRPM7Δkinase mice. Echocardiographic and histopathologic analysis demonstrated cardiac hypertrophy and left ventricular dysfunction in Ang II-treated groups. In TRPM7 kinase-deficient mice, Ang II-induced cardiac functional and structural effects were amplified compared with WT counterparts. Our data demonstrate that in TRPM7Δkinase mice, Ang II-induced hypertension is exaggerated, cardiac remodeling and left ventricular dysfunction are amplified, and endothelial function is impaired. These processes are associated with hypomagnesemia, blunted TRPM7 kinase expression/signaling, endothelial nitric oxide synthase downregulation, and proinflammatory vascular responses. Our findings identify TRPM7 kinase as a novel player in Ang II-induced hypertension

  9. Transient Receptor Potential Melastatin 7 Cation Channel Kinase: New Player in Angiotensin II-Induced Hypertension.

    PubMed

    Antunes, Tayze T; Callera, Glaucia E; He, Ying; Yogi, Alvaro; Ryazanov, Alexey G; Ryazanova, Lillia V; Zhai, Alexander; Stewart, Duncan J; Shrier, Alvin; Touyz, Rhian M

    2016-04-01

    Transient receptor potential melastatin 7 (TRPM7) is a bifunctional protein comprising a magnesium (Mg(2+))/cation channel and a kinase domain. We previously demonstrated that vasoactive agents regulate vascular TRPM7. Whether TRPM7 plays a role in the pathophysiology of hypertension and associated cardiovascular dysfunction is unknown. We studied TRPM7 kinase-deficient mice (TRPM7Δkinase; heterozygous for TRPM7 kinase) and wild-type (WT) mice infused with angiotensin II (Ang II; 400 ng/kg per minute, 4 weeks). TRPM7 kinase expression was lower in heart and aorta from TRPM7Δkinase versus WT mice, effects that were further reduced by Ang II infusion. Plasma Mg(2+) was lower in TRPM7Δkinase versus WT mice in basal and stimulated conditions. Ang II increased blood pressure in both strains with exaggerated responses in TRPM7Δkinase versus WT groups (P<0.05). Acetylcholine-induced vasorelaxation was reduced in Ang II-infused TRPM7Δkinase mice, an effect associated with Akt and endothelial nitric oxide synthase downregulation. Vascular cell adhesion molecule-1 expression was increased in Ang II-infused TRPM7 kinase-deficient mice. TRPM7 kinase targets, calpain, and annexin-1, were activated by Ang II in WT but not in TRPM7Δkinase mice. Echocardiographic and histopathologic analysis demonstrated cardiac hypertrophy and left ventricular dysfunction in Ang II-treated groups. In TRPM7 kinase-deficient mice, Ang II-induced cardiac functional and structural effects were amplified compared with WT counterparts. Our data demonstrate that in TRPM7Δkinase mice, Ang II-induced hypertension is exaggerated, cardiac remodeling and left ventricular dysfunction are amplified, and endothelial function is impaired. These processes are associated with hypomagnesemia, blunted TRPM7 kinase expression/signaling, endothelial nitric oxide synthase downregulation, and proinflammatory vascular responses. Our findings identify TRPM7 kinase as a novel player in Ang II-induced hypertension

  10. Transient receptor potential vanilloid type-1 (TRPV-1) channels contribute to cutaneous thermal hyperaemia in humans.

    PubMed

    Wong, Brett J; Fieger, Sarah M

    2010-11-01

    The initial, rapid increase in skin blood flow in response to direct application of heat is thought to be mediated by an axon reflex, which is dependent on intact cutaneous sensory nerves. We tested the hypothesis that inhibition of transient receptor potential vanilloid type 1 (TRPV-1) channels, which are putative channels located on sensory nerves, would attenuate the skin blood flow response to local heating in humans. Ten subjects were equipped with four microdialysis fibres which were randomly assigned one of four treatments: (1) vehicle control (90% propylene glycol + 10% lactated Ringer solution); (2) 20 mm capsazepine to inhibit TRPV-1 channels; (3) 10 mm l-NAME to inhibit NO synthase; and (4) combined 20 mm capsazepine + 10 mm l-NAME. Following baseline measurements, the temperature of skin heaters was increased from 33°C to 42°C at a rate of 1.0°C every 10 s and local temperature was held at 42°C for 20-30 min until a stable plateau in skin blood flow was achieved. An index of skin blood flow was measured directly over each microdialysis site via laser-Doppler flowmetry (LDF). Beat-by-beat blood pressure was measured via photoplethysmography and verified via automated brachial auscultation. At the end of the local heating protocol, temperature of the heaters was increased to 43°C and 28 mm nitroprusside was infused to achieve maximal vasodilatation. Cutaneous vascular conductance (CVC) was calculated as LDF/mean arterial pressure and normalized to maximal values (%CVCmax). Initial peak in capsazepine (44 ± 4%CVCmax), l-NAME (56 ± 4%CVCmax) and capsazepine + l-NAME (32 ± 6%CVCmax) sites was significantly attenuated compared to control (87 ± 5%CVCmax; P < 0.001 for all conditions). The plateau phase of thermal hyperaemia was significantly attenuated in capsazepine (73 ± 6%CVCmax), l-NAME (47 ± 5%CVCmax) and capsazepine + l-NAME (31 ± 7%CVCmax) sites compared to control (92 ± 5%CVCmax; P < 0.001 for all conditions). These data suggest TRPV-1

  11. Liver receptor homolog-1 (LRH-1): a potential therapeutic target for cancer

    PubMed Central

    Nadolny, Christina; Dong, Xiaoqun

    2015-01-01

    Liver receptor homolog-1 (LRH-1) is a nuclear receptor involved in various biological processes. This nuclear receptor has critical functions in embryonic development as well as in adult homeostasis. Although the physiological functions of LRH-1 in normal breast, pancreas, and intestine have been widely investigated, the dysregulation that occurs during pathological conditions is not well understood. LRH-1 has been implicated in pancreatic, breast, and gastrointestinal cancer, where it exerts its effect of initiation and progression by promoting cell proliferation and metastasis. In addition to mechanistic studies, LRH-1 agonists and antagonists are being explored. Identification and development of endogenous and synthetic ligands has been pursued using computational-based structural analysis. Through ligand identification and a thorough understanding of the pathological roles of LRH-1, new therapeutic avenues for cancer treatment based upon LRH-1 may be a desirable focus for further research. PMID:25951367

  12. NMDA and GABA receptors as potential targets in cough hypersensitivity syndrome.

    PubMed

    Chung, Kian Fan

    2015-06-01

    Chronic cough is a common symptom that can be difficult to treat. It is proposed to be part of a cough hypersensitivity syndrome characterised by troublesome coughing often triggered by low levels of thermal, mechanical or chemical exposure. Upper airway and laryngeal neural dysfunction may also be present. There is evidence that this hypersensitivity may be due to sensory nerve damage caused by inflammatory, infective and allergic factors. Antitussive therapies based on opioid medications are generally not efficacious. Antagonists of N-methyl-d-aspartate receptors in the brain stem and use of GABAB receptor agonists such as baclofen acting centrally and possibly peripherally may represent novel therapeutic approaches.

  13. Xanthurenic Acid Activates mGlu2/3 Metabotropic Glutamate Receptors and is a Potential Trait Marker for Schizophrenia.

    PubMed

    Fazio, Francesco; Lionetto, Luana; Curto, Martina; Iacovelli, Luisa; Cavallari, Michele; Zappulla, Cristina; Ulivieri, Martina; Napoletano, Flavia; Capi, Matilde; Corigliano, Valentina; Scaccianoce, Sergio; Caruso, Alessandra; Miele, Jessica; De Fusco, Antonio; Di Menna, Luisa; Comparelli, Anna; De Carolis, Antonella; Gradini, Roberto; Nisticò, Robert; De Blasi, Antonio; Girardi, Paolo; Bruno, Valeria; Battaglia, Giuseppe; Nicoletti, Ferdinando; Simmaco, Maurizio

    2015-12-08

    The kynurenine pathway of tryptophan metabolism has been implicated in the pathophysiology of psychiatric disorders, including schizophrenia. We report here that the kynurenine metabolite, xanturenic acid (XA), interacts with, and activates mGlu2 and mGlu3 metabotropic glutamate receptors in heterologous expression systems. However, the molecular nature of this interaction is unknown, and our data cannot exclude that XA acts primarily on other targets, such as the vesicular glutamate transporter, in the CNS. Systemic administration of XA in mice produced antipsychotic-like effects in the MK-801-induced model of hyperactivity. This effect required the presence of mGlu2 receptors and was abrogated by the preferential mGlu2/3 receptor antagonist, LY341495. Because the mGlu2 receptor is a potential drug target in the treatment of schizophrenia, we decided to measure serum levels of XA and other kynurenine metabolites in patients affected by schizophrenia. Serum XA levels were largely reduced in a large cohort of patients affected by schizophrenia, and, in patients with first-episode schizophrenia, levels remained low after 12 months of antipsychotic medication. As opposed to other kynurenine metabolites, XA levels were also significantly reduced in first-degree relatives of patients affected by schizophrenia. We suggest that lowered serum XA levels might represent a novel trait marker for schizophrenia.

  14. Xanthurenic Acid Activates mGlu2/3 Metabotropic Glutamate Receptors and is a Potential Trait Marker for Schizophrenia.

    PubMed

    Fazio, Francesco; Lionetto, Luana; Curto, Martina; Iacovelli, Luisa; Cavallari, Michele; Zappulla, Cristina; Ulivieri, Martina; Napoletano, Flavia; Capi, Matilde; Corigliano, Valentina; Scaccianoce, Sergio; Caruso, Alessandra; Miele, Jessica; De Fusco, Antonio; Di Menna, Luisa; Comparelli, Anna; De Carolis, Antonella; Gradini, Roberto; Nisticò, Robert; De Blasi, Antonio; Girardi, Paolo; Bruno, Valeria; Battaglia, Giuseppe; Nicoletti, Ferdinando; Simmaco, Maurizio

    2015-01-01

    The kynurenine pathway of tryptophan metabolism has been implicated in the pathophysiology of psychiatric disorders, including schizophrenia. We report here that the kynurenine metabolite, xanturenic acid (XA), interacts with, and activates mGlu2 and mGlu3 metabotropic glutamate receptors in heterologous expression systems. However, the molecular nature of this interaction is unknown, and our data cannot exclude that XA acts primarily on other targets, such as the vesicular glutamate transporter, in the CNS. Systemic administration of XA in mice produced antipsychotic-like effects in the MK-801-induced model of hyperactivity. This effect required the presence of mGlu2 receptors and was abrogated by the preferential mGlu2/3 receptor antagonist, LY341495. Because the mGlu2 receptor is a potential drug target in the treatment of schizophrenia, we decided to measure serum levels of XA and other kynurenine metabolites in patients affected by schizophrenia. Serum XA levels were largely reduced in a large cohort of patients affected by schizophrenia, and, in patients with first-episode schizophrenia, levels remained low after 12 months of antipsychotic medication. As opposed to other kynurenine metabolites, XA levels were also significantly reduced in first-degree relatives of patients affected by schizophrenia. We suggest that lowered serum XA levels might represent a novel trait marker for schizophrenia. PMID:26643205

  15. Xanthurenic Acid Activates mGlu2/3 Metabotropic Glutamate Receptors and is a Potential Trait Marker for Schizophrenia

    PubMed Central

    Fazio, Francesco; Lionetto, Luana; Curto, Martina; Iacovelli, Luisa; Cavallari, Michele; Zappulla, Cristina; Ulivieri, Martina; Napoletano, Flavia; Capi, Matilde; Corigliano, Valentina; Scaccianoce, Sergio; Caruso, Alessandra; Miele, Jessica; De Fusco, Antonio; Di Menna, Luisa; Comparelli, Anna; De Carolis, Antonella; Gradini, Roberto; Nisticò, Robert; De Blasi, Antonio; Girardi, Paolo; Bruno, Valeria; Battaglia, Giuseppe; Nicoletti, Ferdinando; Simmaco, Maurizio

    2015-01-01

    The kynurenine pathway of tryptophan metabolism has been implicated in the pathophysiology of psychiatric disorders, including schizophrenia. We report here that the kynurenine metabolite, xanturenic acid (XA), interacts with, and activates mGlu2 and mGlu3 metabotropic glutamate receptors in heterologous expression systems. However, the molecular nature of this interaction is unknown, and our data cannot exclude that XA acts primarily on other targets, such as the vesicular glutamate transporter, in the CNS. Systemic administration of XA in mice produced antipsychotic-like effects in the MK-801-induced model of hyperactivity. This effect required the presence of mGlu2 receptors and was abrogated by the preferential mGlu2/3 receptor antagonist, LY341495. Because the mGlu2 receptor is a potential drug target in the treatment of schizophrenia, we decided to measure serum levels of XA and other kynurenine metabolites in patients affected by schizophrenia. Serum XA levels were largely reduced in a large cohort of patients affected by schizophrenia, and, in patients with first-episode schizophrenia, levels remained low after 12 months of antipsychotic medication. As opposed to other kynurenine metabolites, XA levels were also significantly reduced in first-degree relatives of patients affected by schizophrenia. We suggest that lowered serum XA levels might represent a novel trait marker for schizophrenia. PMID:26643205

  16. Recent Progress on the Identification of Metabotropic Glutamate 4 Receptor Ligands and Their Potential Utility as CNS Therapeutics

    PubMed Central

    2011-01-01

    This Review describes recent activity in the advancement of ligands for the metabotropic glutamate 4 receptor subtype and their potential utility as central nervous system (CNS) therapeutics. Until recently, there was a paucity of compounds with suitable selectivity and druglike properties to elucidate the value of this target. The search for selective entities has led several groups to the investigation of allosteric modulators as a path to optimization of potential ligands. Recent efforts, discussed here, have afforded a variety of derivatives with improvements in potency, solubility, and pharmacokinetic properties that garner support for continued investigation and optimization. PMID:22860170

  17. Discovery and Characterization of Novel Allosteric Potentiators of M1 Muscarinic Receptors Reveals Multiple Modes of Activity

    PubMed Central

    Marlo, Joy E.; Niswender, Colleen M.; Days, Emily L.; Bridges, Thomas M.; Xiang, Yun; Rodriguez, Alice L.; Shirey, Jana K.; Brady, Ashley E.; Nalywajko, Tasha; Luo, Qingwei; Austin, Cheryl A.; Williams, Michael Baxter; Kim, Kwangho; Williams, Richard; Orton, Darren; Brown, H. Alex; Lindsley, Craig W.; Weaver, C. David; Conn, P. Jeffrey

    2009-01-01

    Activators of M1 muscarinic acetylcholine receptors (mAChRs) may provide novel treatments for schizophrenia and Alzheimer's disease. Unfortunately, the development of M1-active compounds has resulted in nonselective activation of the highly related M2 to M5 mAChR subtypes, which results in dose-limiting side effects. Using a functional screening approach, we identified several novel ligands that potentiated agonist activation of M1 with low micromolar potencies and induced 5-fold or greater leftward shifts of the acetylcholine (ACh) concentration-response curve. These ligands did not compete for binding at the ACh binding site, indicating that they modulate receptor activity by binding to allosteric sites. The two most selective compounds, cyclopentyl 1,6-dimethyl-4-(6-nitrobenzo[d][1,3]-dioxol-5-yl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (VU0090157) and (E)-2-(4-ethoxyphenylamino)-N′-((2-hydroxynaphthalen-1-yl)methylene)acetohydrazide (VU0029767), induced progressive shifts in ACh affinity at M1 that were consistent with their effects in a functional assay, suggesting that the mechanism for enhancement of M1 activity by these compounds is by increasing agonist affinity. These compounds were strikingly different, however, in their ability to potentiate responses at a mutant M1 receptor with decreased affinity for ACh and in their ability to affect responses of the allosteric M1 agonist, 1-[1′-(2-tolyl)-1,4′-bipiperidin-4-yl]-1,3-dihydro-2H-benzimidazol-2-one. Furthermore, these two compounds were distinct in their abilities to potentiate M1-mediated activation of phosphoinositide hydrolysis and phospholipase D. The discovery of multiple structurally distinct positive allosteric modulators of M1 is an exciting advance in establishing the potential of allosteric modulators for selective activation of this receptor. These data also suggest that structurally diverse M1 potentiators may act by distinct mechanisms and differentially regulate receptor

  18. Amisulpride-induced seizurogenic effect: a potential role of opioid receptor-linked transduction systems.

    PubMed

    Rehni, Ashish K; Singh, Thakur Gurjeet; Chand, Prem

    2011-05-01

    This study was designed to investigate the role of opioid receptors, gamma-aminobutyric acid (GABA) receptors, mast cells and histamine receptors (H(1) subtype) in the seizurogenic effect of amisulpride on mice. A single injection of amisulpride (180 mg/kg) was employed to evaluate the seizurogenicity of the drug in mice. Seizures were assessed in terms of a composite seizure severity score (SSS), time of the onset of straub-like tail, onset of jerky movements of whole body, convulsions and death. Amisulpride administration (180 mg/kg) induced a significant pro-convulsant effect in mice as measured in terms of the SSS (21.12 ± 2.71) and a significant decrease in the time latency of the onset of straub-like tail (132.45 ± 12.31), jerky movements of whole body (153.28 ± 14.12), convulsions (184.97 ± 13.11) and death (100%). Moreover, prior administration of naloxone, cetrizine, sodium cromoglycate and gabapentin, respectively, attenuated this seizurogenic activity that amisulpride exerted on mice (p < 0.05). Therefore, it may be suggested that amisulpride exerts a seizurogenic effect on mice possibly via an opioid receptor activation-dependent release of histamine from the mast cells and a simultaneous inhibition of GABA release.

  19. ß-Adrenergic Receptor Signaling and Modulation of Long-Term Potentiation in the Mammalian Hippocampus

    ERIC Educational Resources Information Center

    O'Dell, Thomas J.; Connor, Steven A.; Guglietta, Ryan; Nguyen, Peter V.

    2015-01-01

    Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the…

  20. Cross species sensitivity to a novel androgen receptor agonist of potential environmental concern, spironolactone

    EPA Science Inventory

    Spironolactone (SPL) is a pharmaceutical that is used in humans as an androgen receptor (AR) antagonist to treat conditions like hirsutism, various dermatologic afflictions, and female pattern hair loss, in addition to its common usage as a diuretic to treat hypertension. Althoug...

  1. Activation of the Farnesoid X-receptor in breast cancer cell lines results in cytotoxicity but not increased migration potential.

    PubMed

    Alasmael, Noura; Mohan, Rati; Meira, Lisiane B; Swales, Karen E; Plant, Nick J

    2016-01-28

    Breast cancer is the commonest form of cancer in women, but successful treatment is confounded by the heterogeneous nature of breast tumours: Effective treatments exist for hormone-sensitive tumours, but triple-negative breast cancer results in poor survival. An area of increasing interest is metabolic reprogramming, whereby drug-induced alterations in the metabolic landscape of a tumour slow tumour growth and/or increase sensitivity to existing therapeutics. Nuclear receptors are transcription factors central to the expression of metabolic and transport proteins, and thus represent potential targets for metabolic reprogramming. We show that activation of the nuclear receptor FXR, either by its endogenous ligand CDCA or the synthetic GW4064, leads to cell death in four breast cancer cell lines with distinct phenotypes: MCF-10A (normal), MCF-7 (receptor positive), MDA-MB-231 and MDA-MB-468 (triple negative). Furthermore, we show that the mechanism of cell death is predominantly through the intrinsic apoptotic pathway. Finally, we demonstrate that FXR agonists do not stimulate migration in breast cancer cell lines, an important potential adverse effect. Together, our data support the continued examination of FXR agonists as a novel class of therapeutics for the treatment of breast cancer.

  2. Transient receptor potential ankyrin 1 antagonists block the noxious effects of toxic industrial isocyanates and tear gases

    PubMed Central

    Bessac, Bret F.; Sivula, Michael; von Hehn, Christian A.; Caceres, Ana I.; Escalera, Jasmine; Jordt, Sven-Eric

    2009-01-01

    The release of methyl isocyanate in Bhopal, India, caused the worst industrial accident in history. Exposures to industrial isocyanates induce lacrimation, pain, airway irritation, and edema. Similar responses are elicited by chemicals used as tear gases. Despite frequent exposures, the biological targets of isocyanates and tear gases in vivo have not been identified, precluding the development of effective countermeasures. We use Ca2+ imaging and electrophysiology to show that the noxious effects of isocyanates and those of all major tear gas agents are caused by activation of Ca2+ influx and membrane currents in mustard oil-sensitive sensory neurons. These responses are mediated by transient receptor potential ankyrin 1 (TRPA1), an ion channel serving as a detector for reactive chemicals. In mice, genetic ablation or pharmacological inhibition of TRPA1 dramatically reduces isocyanate- and tear gas-induced nocifensive behavior after both ocular and cutaneous exposures. We conclude that isocyanates and tear gas agents target the same neuronal receptor, TRPA1. Treatment with TRPA1 antagonists may prevent and alleviate chemical irritation of the eyes, skin, and airways and reduce the adverse health effects of exposures to a wide range of toxic noxious chemicals.—Bessac, B. F., Sivula, M., von Hehn, C. A., Caceres, A. I., Escalera, J., Jordt, S.-E. Transient receptor potential ankyrin 1 antagonists block the noxious effects of toxic industrial isocyanates and tear gases. PMID:19036859

  3. Radiosynthesis and Evaluation of [11C]EMPA as a potential PET Tracer for Orexin 2 Receptors

    PubMed Central

    Wang, Changning; Moseley, Christian K.; Carlin, Stephen M.; Wilson, Colin M.; Neelamegam, Ramesh; Hooker, Jacob M.

    2013-01-01

    EMPA is a selective antagonist of orexin 2 (OX2) receptors. Previous literature with [3H]-EMPA suggest that it may be used as an imaging agent for OX2 receptors; however, brain penetration is known to be modest. To evaluate the potential of EMPA as a PET radiotracer in non-human primate (as a step to imaging in man), we radiolabeled EMPA with carbon-11. Radiosynthesis of [11C]N-ethyl-2-(N-(6-methoxypyridin-3-yl)-2-methylphenylsulfonamido)-N-(pyridin-3-ylmethyl)acetamide ([11C]EMPA), and evaluation as a potential PET tracer for OX2 receptors is described. Synthesis of an appropriate non-radioactive O-desmethyl precursor was achieved from EMPA with sodium iodide and chlorotrimethylsilane. Selective O-methylation using [11C]CH3I in the presence of cesium carbonate in DMSO at room temp afforded [11C]EMPA in 1.5–2.5% yield (non-decay corrected relative to trapped [11C]CH3I at EOS) with ≥95 % chemical and radiochemical purities. The total synthesis time was 34–36 min from EOB. Studies in rodent suggested that uptake in tissue was dominated by nonspecific binding. However, [11C]EMPA also showed poor uptake in both rats and baboon as measured with PET imaging. PMID:23601709

  4. AMPA receptor potentiation by acetylcholinesterase is age-dependently upregulated at synaptogenesis sites of the rat brain

    PubMed Central

    Olivera, Silvia; Henley, Jeremy M.; Rodriguez-Ithurralde, Daniel

    2012-01-01

    We have used radioligand binding to synaptic membranes from distinct rat brain regions and quantitative autoradiography to investigate the postnatal evolution of acetylcholinesterase (AChE)-evoked up-regulation of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in CNS areas undergoing synaptogenesis. Incubation of synaptosomal membranes or brain sections with purified AChE caused a developmentally modulated enhancement in the binding of [3H]-(S)–AMPA and the specific AMPA receptor ligand [3H]-(S)-5–fluorowillardiine, but did not modify binding to kainate neither N-methyl-D-aspartate receptors. In all postnatal ages investigated (4, 7, 14, 20, 27, 40 days-old and adult rats), AChE effect on binding was concentration-dependent and blocked by propidium, BW 284c51, diisopropylfluorophosphonate and eserine, therefore requiring indemnity of both peripheral and active sites of the enzyme. AChE-mediated enhancement of [3H]-fluorowillardiine binding was measurable in all major CNS areas, but displayed remarkable anatomical selectivity and developmental regulation. Autoradiograph densitometry exhibited distinct temporal profiles and peaks of treated/control binding ratios for different cortices, cortical layers, and nuclei. Within the parietal, occipital and temporal neocortices, hippocampal CA1 field and cerebellum, AChE-potentiated binding ratios peaked in chronological correspondence with synaptogenesis periods of the respective AMPA-receptor containing targets. This modulation of AMPA receptors by AChE is a molecular mechanism able to transduce localized neural activity into durable modifications of synaptic molecular structure and function. It might also contribute to AChE-mediated neurotoxicity, as postulated in Alzheimer’s disease and other CNS disorders. PMID:12565696

  5. The Roles of Rasd1 small G proteins and leptin in the activation of TRPC4 transient receptor potential channels

    PubMed Central

    Wie, Jinhong; Kim, Byung Joo; Myeong, Jongyun; Ha, Kotdaji; Jeong, Seung Joo; Yang, Dongki; Kim, Euiyong; Jeon, Ju-Hong; So, Insuk

    2015-01-01

    TRPC4 is important regulators of electrical excitability in gastrointestinal myocytes, pancreatic β-cells and neurons. Much is known regarding the assembly and function of these channels including TRPC1 as a homotetramer or a heteromultimer and the roles that their interacting proteins play in controlling these events. Further, they are one of the best-studied targets of G protein-coupled receptors and growth factors in general and Gαi/o and Gαq protein coupled receptor or epidermal growth factor and leptin in particular. However, our understanding of the roles of small G proteins and leptin on TRPC4 channels is still rudimentary. We discuss potential roles for Rasd1 small G protein and leptin in channel activation in addition to their known role in cellular signaling. PMID:26083271

  6. Gene Expression of Growth Factors and Growth Factor Receptors for Potential Targeted Therapy of Canine Hepatocellular Carcinoma

    PubMed Central

    IIDA, Gentoku; ASANO, Kazushi; SEKI, Mamiko; SAKAI, Manabu; KUTARA, Kenji; ISHIGAKI, Kumiko; KAGAWA, Yumiko; YOSHIDA, Orie; TESHIMA, Kenji; EDAMURA, Kazuya; WATARI, Toshihiro

    2013-01-01

    ABSTRACT The purpose of this study was to evaluate the gene expression of growth factors and growth factor receptors of primary hepatic masses, including hepatocellular carcinoma (HCC) and nodular hyperplasia (NH), in dogs. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed to measure the expression of 18 genes in 18 HCCs, 10 NHs, 11 surrounding non-cancerous liver tissues and 4 healthy control liver tissues. Platelet-derived growth factor-B (PDGF-B), transforming growth factor-α, epidermal growth factor receptor, epidermal growth factor and hepatocyte growth factor were found to be differentially expressed in HCC compared with NH and the surrounding non-cancerous and healthy control liver tissues. PDGF-B is suggested to have the potential to become a valuable ancillary target for the treatment of canine HCC. PMID:24189579

  7. Potentiation of mGlu5 receptors with the novel enhancer, VU0360172, reduces spontaneous absence seizures in WAG/Rij rats.

    PubMed

    D'Amore, V; Santolini, I; van Rijn, C M; Biagioni, F; Molinaro, G; Prete, A; Conn, P J; Lindsley, C W; Zhou, Y; Vinson, P N; Rodriguez, A L; Jones, C K; Stauffer, S R; Nicoletti, F; van Luijtelaar, G; Ngomba, R T

    2013-03-01

    Absence epilepsy is generated by the cortico-thalamo-cortical network, which undergoes a finely tuned regulation by metabotropic glutamate (mGlu) receptors. We have shown previously that potentiation of mGlu1 receptors reduces spontaneous occurring spike and wave discharges (SWDs) in the WAG/Rij rat model of absence epilepsy, whereas activation of mGlu2/3 and mGlu4 receptors produces the opposite effect. Here, we have extended the study to mGlu5 receptors, which are known to be highly expressed within the cortico-thalamo-cortical network. We used presymptomatic and symptomatic WAG/Rij rats and aged-matched ACI rats. WAG/Rij rats showed a reduction in the mGlu5 receptor protein levels and in the mGlu5-receptor mediated stimulation of polyphosphoinositide hydrolysis in the ventrobasal thalamus, whereas the expression of mGlu5 receptors was increased in the somatosensory cortex. Interestingly, these changes preceded the onset of the epileptic phenotype, being already visible in pre-symptomatic WAG/Rij rats. SWDs in symptomatic WAG/Rij rats were not influenced by pharmacological blockade of mGlu5 receptors with MTEP (10 or 30 mg/kg, i.p.), but were significantly decreased by mGlu5 receptor potentiation with the novel enhancer, VU0360172 (3 or 10 mg/kg, s.c.), without affecting motor behaviour. The effect of VU0360172 was prevented by co-treatment with MTEP. These findings suggest that changes in mGlu5 receptors might lie at the core of the absence-seizure prone phenotype of WAG/Rij rats, and that mGlu5 receptor enhancers are potential candidates to the treatment of absence epilepsy. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'. PMID:22705340

  8. Structure-based design of eugenol analogs as potential estrogen receptor antagonists.

    PubMed

    Anita, Yulia; Radifar, Muhammad; Kardono, Leonardus Bs; Hanafi, Muhammad; Istyastono, Enade P

    2012-01-01

    Eugenol is an essential oil mainly found in the buds and leaves of clove (Syzygium aromaticum (L.) Merrill and Perry), which has been reported to have activity on inhibition of cell proliferation and apoptosis induction in human MCF-7 breast cancer cells. This biological activity is correlated to its activity as an estrogen receptor antagonist. In this article, we present the construction and validation of structure-based virtual screening (SBVS) protocols to identify the potent estrogen receptor α (ER) antagonists. The selected protocol, which gave acceptable enrichment factors as a virtual screening protocol, subsequently used to virtually screen eugenol, its analogs and their dimers. Based on the virtual screening results, dimer eugenol of 4-[4-hydroxy-3-(prop-2-en-1- yl)phenyl]-2-(prop-2-en-1-yl)phenol is recommended to be developed further in order to discover novel and potent ER antagonists. PMID:23144548

  9. Potentiation of Peptide Receptor Radionuclide Therapy by the PARP Inhibitor Olaparib

    PubMed Central

    Nonnekens, Julie; van Kranenburg, Melissa; Beerens, Cecile E.M.T.; Suker, Mustafa; Doukas, Michael; van Eijck, Casper H.J.; de Jong, Marion; van Gent, Dik C.

    2016-01-01

    Metastases expressing tumor-specific receptors can be targeted and treated by binding of radiolabeled peptides (peptide receptor radionuclide therapy or PRRT). For example, patients with metastasized somatostatin receptor-positive neuroendocrine tumors (NETs) can be treated with radiolabeled somatostatin analogues, resulting in strongly increased progression-free survival and quality of life. There is nevertheless still room for improvement, as very few patients can be cured at this stage of disease. We aimed to specifically sensitize replicating tumor cells without further damage to healthy tissues. Thereto we investigated the DNA damaging effects of PRRT with the purpose to enhance these effects through modulation of the DNA damage response. Although PRRT induces DNA double strand breaks (DSBs), a larger fraction of the induced lesions are single strand breaks (expected to be similar to those induced by external beam radiotherapy) that require poly-[ADP-ribose]-polymerase 1 (PARP-1) activity for repair. If these breaks cannot be repaired, they will cause replication fork arrest and DSB formation during replication. Therefore, we used the PARP-1 inhibitor Olaparib to increase the number of cytotoxic DSBs. Here we show that this new combination strategy synergistically sensitized somatostatin receptor expressing cells to PRRT. We observed increased cell death and reduced cellular proliferation compared to the PRRT alone. The enhanced cell death was caused by increased numbers of DSBs that are repaired with remarkably slow kinetics, leading to genome instability. Furthermore, we validated the increased DSB induction after PARP inhibitor addition in the clinically relevant model of living human NET slices. We expect that this combined regimen can thus augment current PRRT outcomes. PMID:27570553

  10. Design and evaluation of xanthine based adenosine receptor antagonists: Potential hypoxia targeted immunotherapies

    PubMed Central

    Thomas, Rhiannon; Lee, Joslynn; Chevalier, Vincent; Sadler, Sara; Selesniemi, Kaisa; Hatfield, Stephen; Sitkovsky, Michail; Ondrechen, Mary Jo; Jones, Graham B.

    2015-01-01

    Molecular modeling techniques were applied to the design, synthesis and optimization of a new series of xanthine based adenosine A2A receptor antagonists. The optimized lead compound was converted to a PEG derivative and a functional in vitro bioassay used to confirm efficacy. Additionally, the PEGylated version showed enhanced aqueous solubility and was inert to photoisomerization, a known limitation of existing antagonists of this class. PMID:24126093

  11. Dopamine receptor modulation of repetitive grooming actions in the rat: potential relevance for Tourette syndrome.

    PubMed

    Taylor, Jennifer L; Rajbhandari, Abha K; Berridge, Kent C; Aldridge, J Wayne

    2010-03-31

    Studies of rodent grooming can provide valuable insight for dopamine contributions to the initiation, organization, and repetition of motor patterns. This information is useful for understanding how brain dysfunctions contribute to movement disorders such as Tourette syndrome and obsessive compulsive disorder, in which patients are driven to reiterate particular movement patterns. In rodents, dopamine D1 receptor stimulation causes a complex behavioral super-stereotypy in the form of excessive production and rigid execution of whole sequences of movements known as syntactic grooming chains. Sequential super-stereotypy of grooming chains may be particularly advantageous for modeling movement sequences and treatments in Tourette syndrome and related disorders. Here, we report that co-administration of haloperidol, one available treatment for Tourette syndrome and primarily a D2 receptor antagonist, prevented D1 stimulation with SKF38393 from inducing sequential super-stereotypy, which manifests as an exaggeration of the tendency to complete all four phases of a syntactic chain in rigid serial order once the first phase has begun. In a separate experiment, we showed that in contrast to acute D1 agonist administration, 39h withdrawal from chronic (3weeks) administration of the D1 antagonist SCH23390 (which has been suggested to increase D1 receptor expression in the basal ganglia) did not elicit sequential super-stereotypy after drug cessation. Instead, rats suddenly removed from repeated SCH23390 spent more time performing simple stereotypies that included intense scratching and biting behaviors. Together, these results have implications for understanding how dopamine receptors facilitate particular stereotypies manifest in animal models of Tourette syndrome and obsessive compulsive disorder.

  12. Potentiation of Peptide Receptor Radionuclide Therapy by the PARP Inhibitor Olaparib.

    PubMed

    Nonnekens, Julie; van Kranenburg, Melissa; Beerens, Cecile E M T; Suker, Mustafa; Doukas, Michael; van Eijck, Casper H J; de Jong, Marion; van Gent, Dik C

    2016-01-01

    Metastases expressing tumor-specific receptors can be targeted and treated by binding of radiolabeled peptides (peptide receptor radionuclide therapy or PRRT). For example, patients with metastasized somatostatin receptor-positive neuroendocrine tumors (NETs) can be treated with radiolabeled somatostatin analogues, resulting in strongly increased progression-free survival and quality of life. There is nevertheless still room for improvement, as very few patients can be cured at this stage of disease. We aimed to specifically sensitize replicating tumor cells without further damage to healthy tissues. Thereto we investigated the DNA damaging effects of PRRT with the purpose to enhance these effects through modulation of the DNA damage response. Although PRRT induces DNA double strand breaks (DSBs), a larger fraction of the induced lesions are single strand breaks (expected to be similar to those induced by external beam radiotherapy) that require poly-[ADP-ribose]-polymerase 1 (PARP-1) activity for repair. If these breaks cannot be repaired, they will cause replication fork arrest and DSB formation during replication. Therefore, we used the PARP-1 inhibitor Olaparib to increase the number of cytotoxic DSBs. Here we show that this new combination strategy synergistically sensitized somatostatin receptor expressing cells to PRRT. We observed increased cell death and reduced cellular proliferation compared to the PRRT alone. The enhanced cell death was caused by increased numbers of DSBs that are repaired with remarkably slow kinetics, leading to genome instability. Furthermore, we validated the increased DSB induction after PARP inhibitor addition in the clinically relevant model of living human NET slices. We expect that this combined regimen can thus augment current PRRT outcomes. PMID:27570553

  13. Characteristics of albumin binding to opossum kidney cells and identification of potential receptors.

    PubMed

    Brunskill, N J; Nahorski, S; Walls, J

    1997-02-01

    Albumin re-absorption in the kidney proximal tubule may be pathophysiological in disease. Opossum kidney (OK) cell monolayers were used to investigate the characteristics of [125I]-labelled albumin binding at 4 degrees C. Two binding sites were identified, one with high affinity (KD 154.8 +/-7 mg/l) and low capacity, the other with low affinity (KD 8300 +/- 1000 mg/l) and high capacity. Binding was sensitive to lectins Glycine max and Ulex europaeus I, but not other lectins, indicating involvement of a glycoprotein(s) in the binding process. Binding was also sensitive to a number of agents known to inhibit binding to scavenger receptors. [125I]-Labelled albumin ligand blotting of OK cell membrane proteins identified several albumin-binding proteins with identical lectin affinities to those proteins mediating albumin binding to OK cell monolayers. These results provide initial evidence of the identity of albumin receptors in kidney tubules, and suggest that they may be members of the family of scavenger receptors. PMID:9000429

  14. A novel GABA(A) alpha 5 receptor inhibitor with therapeutic potential.

    PubMed

    Ling, István; Mihalik, Balázs; Etherington, Lori-An; Kapus, Gábor; Pálvölgyi, Adrienn; Gigler, Gábor; Kertész, Szabolcs; Gaál, Attila; Pallagi, Katalin; Kiricsi, Péter; Szabó, Éva; Szénási, Gábor; Papp, Lilla; Hársing, László G; Lévay, György; Spedding, Michael; Lambert, Jeremy J; Belelli, Delia; Barkóczy, József; Volk, Balázs; Simig, Gyula; Gacsályi, István; Antoni, Ferenc A

    2015-10-01

    Novel 2,3-benzodiazepine and related isoquinoline derivatives, substituted at position 1 with a 2-benzothiophenyl moiety, were synthesized to produce compounds that potently inhibited the action of GABA on heterologously expressed GABAA receptors containing the alpha 5 subunit (GABAA α5), with no apparent affinity for the benzodiazepine site. Substitutions of the benzothiophene moiety at position 4 led to compounds with drug-like properties that were putative inhibitors of extra-synaptic GABAA α5 receptors and had substantial blood-brain barrier permeability. Initial characterization in vivo showed that 8-methyl-5-[4-(trifluoromethyl)-1-benzothiophen-2-yl]-1,9-dihydro-2H-[1,3]oxazolo[4,5-h][2,3]benzodiazepin-2-one was devoid of sedative, pro-convulsive or motor side-effects, and enhanced the performance of rats in the object recognition test. In summary, we have discovered a first-in-class GABA-site inhibitor of extra-synaptic GABAA α5 receptors that has promising drug-like properties and warrants further development.

  15. Potential insight for drug discovery from high fidelity receptor-mediated transduction mechanisms in insects

    PubMed Central

    Raffa, Robert B.; Raffa, Kenneth F.

    2011-01-01

    Introduction There is a pervasive and growing concern about the small number of new pharmaceutical agents. There are many proposed explanations for this trend that do not involve the drug-discovery process per se, but the discovery process itself has also come under scrutiny. If the current paradigms are indeed not working, where are novel ideas to come from? Perhaps it is time to look to novel sources. Areas covered The receptor-signaling and 2nd-messenger transduction processes present in insects are quite similar to those in mammals (involving G proteins, ion channels, etc.). However, a review of these systems reveals an unprecedented degree of high potency and receptor selectivity to an extent greater than that modeled in most current drug-discovery approaches. Expert opinion A better understanding of insect receptor pharmacology could stimulate novel theoretical and practical ideas in mammalian pharmacology (drug discovery) and, conversely, the application of pharmacology and medicinal chemistry principles could stimulate novel advances in entomology (safer and more targeted control of pest species). PMID:21984882

  16. β-arrestin-2-biased agonism of delta opioid receptors sensitizes transient receptor potential vanilloid type 1 (TRPV1) in primary sensory neurons.

    PubMed

    Rowan, Matthew P; Szteyn, Kalina; Doyle, Allison P; Gomez, Ruben; Henry, Michael A; Jeske, Nathaniel A

    2014-01-01

    Despite advances in understanding the signaling mechanisms involved in the development and maintenance of chronic pain, the pharmacologic treatment of chronic pain has seen little advancement. Agonists at the mu opioid receptor (MOPr) continue to be vital in the treatment of many forms of chronic pain, but side-effects limit their clinical utility and range from relatively mild, such as constipation, to major, such as addiction and dependence. Additionally, chronic activation of MOPr results in pain hypersensitivity known as opioid-induced hyperalgesia (OIH), and we have shown recently that recruitment of β-arrestin2 to MOPr, away from transient potential vanilloid eceptor type 1 (TRPV1) in primary sensory neurons contributes to this phenomenon. The delta opioid receptor (DOPr) has become a promising target for the treatment of chronic pain, but little is known about the effects of chronic activation of DOPr on nociceptor sensitivity and OIH. Here we report that chronic activation of DOPr by the DOPr-selective agonist, SNC80, results in the sensitization of TRPV1 and behavioral signs of OIH via β-arrestin2 recruitment to DOPr and away from TRPV1. Conversely, chronic treatment with ARM390, a DOPr-selective agonist that does not recruit β-arrestin2, neither sensitized TRPV1 nor produced OIH. Interestingly, the effect of SNC80 to sensitize TRPV1 is species-dependent, as rats developed OIH but mice did not. Taken together, the reported data identify a novel side-effect of chronic administration of β-arrestin2-biased DOPr agonists and highlight the importance of potential species-specific effects of DOPr agonists.

  17. Fear potentiated startle increases phospholipase D (PLD) expression/activity and PLD-linked metabotropic glutamate receptor mediated post-tetanic potentiation in rat amygdala.

    PubMed

    Krishnan, Balaji; Scott, Michael T; Pollandt, Sebastian; Schroeder, Bradley; Kurosky, Alexander; Shinnick-Gallagher, Patricia

    2016-02-01

    Long-term memory (LTM) of fear stores activity dependent modifications that include changes in amygdala signaling. Previously, we identified an enhanced probability of release of glutamate mediated signaling to be important in rat fear potentiated startle (FPS), a well-established translational behavioral measure of fear. Here, we investigated short- and long-term synaptic plasticity in FPS involving metabotropic glutamate receptors (mGluRs) and associated downstream proteomic changes in the thalamic-lateral amygdala pathway (Th-LA). Aldolase A, an inhibitor of phospholipase D (PLD), expression was reduced, concurrent with significantly elevated PLD protein expression. Blocking the PLD-mGluR signaling significantly reduced PLD activity. While transmitter release probability increased in FPS, PLD-mGluR agonist and antagonist actions were occluded. In the unpaired group (UNP), blocking the PLD-mGluR increased while activating the receptor decreased transmitter release probability, consistent with decreased synaptic potentials during tetanic stimulation. FPS Post-tetanic potentiation (PTP) immediately following long-term potentiation (LTP) induction was significantly increased. Blocking PLD-mGluR signaling prevented PTP and reduced cumulative PTP probability but not LTP maintenance in both groups. These effects are similar to those mediated through mGluR7, which is co-immunoprecipitated with PLD in FPS. Lastly, blocking mGluR-PLD in the rat amygdala was sufficient to prevent behavioral expression of fear memory. Thus, our study in the Th-LA pathway provides the first evidence for PLD as an important target of mGluR signaling in amygdala fear-associated memory. Importantly, the PLD-mGluR provides a novel therapeutic target for treating maladaptive fear memories in posttraumatic stress and anxiety disorders.

  18. Mechano-perception in Chara cells: the influence of salinity and calcium on touch-activated receptor potentials, action potentials and ion transport.

    PubMed

    Shepherd, Virginia A; Beilby, Mary J; Al Khazaaly, Sabah A S; Shimmen, Teruo

    2008-11-01

    This paper investigates the impact of increased salinity on touch-induced receptor and action potentials of Chara internodal cells. We resolved underlying changes in ion transport by current/voltage analysis. In a saline medium with a low Ca(2+) ion concentration [(Ca(2+))(ext)], the cell background conductance significantly increased and proton pump currents declined to negligible levels, depolarizing the membrane potential difference (PD) to the excitation threshold [action potential (AP)(threshold)]. The onset of spontaneous repetitive action potentials further depolarized the PD, activating K(+) outward rectifying (KOR) channels. K(+) efflux was then sustained and irrevocable, and cells were desensitized to touch. However, when [Ca(2+)](ext) was high, the background conductance increased to a lesser extent and proton pump currents were stimulated, establishing a PD narrowly negative to AP(threshold). Cells did not spontaneously fire, but became hypersensitive to touch. Even slight touch stimulus induced an action potential and further repetitive firing. The duration of each excitation was extended when [Ca(2+)](ext) was low. Cell viability was prolonged in the absence of touch stimulus. Chara cells eventually depolarize and die in the saline media, but touch-stimulated and spontaneous excitation accelerates the process in a Ca(2+)-dependent manner. Our results have broad implications for understanding the interactions between mechano-perception and salinity stress in plants.

  19. Potentiation of estrogen receptor activation function 1 (AF-1) by Src/JNK through a serine 118-independent pathway.

    PubMed

    Feng, W; Webb, P; Nguyen, P; Liu, X; Li, J; Karin, M; Kushner, P J

    2001-01-01

    Estrogen receptor (ER) is activated either by ligand or by signals from tyrosine kinase-linked cell surface receptors. We investigated whether the nonreceptor Src tyrosine kinase could affect ER activity. Expression of constitutively active Src or stimulation of the endogenous Src/JNK pathway enhances transcriptional activation by the estrogen-ER complex and strongly stimulates the otherwise weak activation by the unliganded ER and the tamoxifen-ER complex. Src affects ER activation function 1 (AF-1), and not ER AF-2, and does so through its tyrosine kinase activity. This effect of Src is mediated partly through a Raf/mitogen-activated ERK kinase/extracellular signal-regulated kinase (Raf/MEK/ERK) signaling cascade and partly through a MEKK/JNKK/JNK cascade. Although, as previously shown, Src action through activated ERK stimulates AF-1 by phosphorylation at S118, Src action through activated JNK neither leads to phosphorylation of S118 nor requires S118 for its action. We therefore suggest that the Src/JNK pathway enhances AF-1 activity by modification of ER AF-1-associated proteins. Src potentiates activation functions in CREB-binding protein (CBP) and glucocorticoid receptor interacting protein 1 (GRIP1), and we discuss the possibility that the Src/JNK pathway enhances the activity of these coactivators, which are known to mediate AF-1 action. PMID:11145737

  20. The Pyrexia transient receptor potential channel mediates circadian clock synchronization to low temperature cycles in Drosophila melanogaster.

    PubMed

    Wolfgang, Werner; Simoni, Alekos; Gentile, Carla; Stanewsky, Ralf

    2013-10-01

    Circadian clocks are endogenous approximately 24 h oscillators that temporally regulate many physiological and behavioural processes. In order to be beneficial for the organism, these clocks must be synchronized with the environmental cycles on a daily basis. Both light : dark and the concomitant daily temperature cycles (TCs) function as Zeitgeber ('time giver') and efficiently entrain circadian clocks. The temperature receptors mediating this synchronization have not been identified. Transient receptor potential (TRP) channels function as thermo-receptors in animals, and here we show that the Pyrexia (Pyx) TRP channel mediates temperature synchronization in Drosophila melanogaster. Pyx is expressed in peripheral sensory organs (chordotonal organs), which previously have been implicated in temperature synchronization. Flies deficient for Pyx function fail to synchronize their behaviour to TCs in the lower range (16-20°C), and this deficit can be partially rescued by introducing a wild-type copy of the pyx gene. Synchronization to higher TCs is not affected, demonstrating a specific role for Pyx at lower temperatures. In addition, pyx mutants speed up their clock after being exposed to TCs. Our results identify the first TRP channel involved in temperature synchronization of circadian clocks.

  1. Heat Avoidance Is Regulated by Transient Receptor Potential (TRP) Channels and a Neuropeptide Signaling Pathway in Caenorhabditis elegans

    PubMed Central

    Glauser, Dominique A.; Chen, Will C.; Agin, Rebecca; MacInnis, Bronwyn L.; Hellman, Andrew B.; Garrity, Paul A.; Tan, Man-Wah; Goodman, Miriam B.

    2011-01-01

    The ability to avoid noxious extremes of hot and cold is critical for survival and depends on thermal nociception. The TRPV subset of transient receptor potential (TRP) channels is heat activated and proposed to be responsible for heat detection in vertebrates and fruit flies. To gain insight into the genetic and neural basis of thermal nociception, we developed assays that quantify noxious heat avoidance in the nematode Caenorhabditis elegans and used them to investigate the genetic basis of this behavior. First, we screened mutants for 18 TRP channel genes (including all TRPV orthologs) and found only minor defects in heat avoidance in single and selected double and triple mutants, indicating that other genes are involved. Next, we compared two wild isolates of C. elegans that diverge in their threshold for heat avoidance and linked this phenotypic variation to a polymorphism in the neuropeptide receptor gene npr-1. Further analysis revealed that loss of either the NPR-1 receptor or its ligand, FLP-21, increases the threshold for heat avoidance. Cell-specific rescue of npr-1 implicates the interneuron RMG in the circuit regulating heat avoidance. This neuropeptide signaling pathway operates independently of the TRPV genes, osm-9 and ocr-2, since mutants lacking npr-1 and both TRPV channels had more severe defects in heat avoidance than mutants lacking only npr-1 or both osm-9 and ocr-2. Our results show that TRPV channels and the FLP-21/NPR-1 neuropeptide signaling pathway determine the threshold for heat avoidance in C. elegans. PMID:21368276

  2. Potentiation of mGlu5 receptors with the novel enhancer, VU0360172, reduces spontaneous absence seizures in WAG/Rij rats

    PubMed Central

    D’Amore, V.; Santolini, I.; van Rijn, C.M.; Biagioni, F.; Molinaro, G.; Prete, A.; Conn, P.J.; Lindsley, C.W.; Zhou, Y.; Vinson, P.N.; Rodriguez, A.L.; Jones, C.K.; Stauffer, S.R.; Nicoletti, F.; van Luijtelaar, G.; Ngomba, R.T.

    2013-01-01

    Absence epilepsy is generated by the cortico-thalamo-cortical network, which undergoes a finely tuned regulation by metabotropic glutamate (mGlu) receptors. We have shown previously that potentiation of mGlu1 receptors reduces spontaneous occurring spike and wave discharges (SWDs) in the WAG/Rij rat model of absence epilepsy, whereas activation of mGlu2/3 and mGlu4 receptors produces the opposite effect. Here, we have extended the study to mGlu5 receptors, which are known to be highly expressed within the cortico-thalamo-cortical network. We used presymptomatic and symptomatic WAG/Rij rats and aged-matched ACI rats. WAG/Rij rats showed a reduction in the mGlu5 receptor protein levels and in the mGlu5-receptor mediated stimulation of polyphosphoinositide hydrolysis in the ventrobasal thalamus, whereas the expression of mGlu5 receptors was increased in the somatosensory cortex. Interestingly, these changes preceded the onset of the epileptic phenotype, being already visible in pre-symptomatic WAG/Rij rats. SWDs in symptomatic WAG/Rij rats were not influenced by pharmacological blockade of mGlu5 receptors with MTEP (10 or 30 mg/kg, i.p.), but were significantly decreased by mGlu5 receptor potentiation with the novel enhancer, VU0360172 (3 or 10 mg/kg, s.c.), without affecting motor behaviour. The effect of VU0360172 was prevented by co-treatment with MTEP. These findings suggest that changes in mGlu5 receptors might lie at the core of the absence-seizure prone phenotype of WAG/Rij rats, and that mGlu5 receptor enhancers are potential candidates to the treatment of absence epilepsy. PMID:22705340

  3. Allosteric modulators of NR2B-containing NMDA receptors: molecular mechanisms and therapeutic potential.

    PubMed

    Mony, Laetitia; Kew, James N C; Gunthorpe, Martin J; Paoletti, Pierre

    2009-08-01

    N-methyl-D-aspartate receptors (NMDARs) are ion channels gated by glutamate, the major excitatory neurotransmitter in the mammalian central nervous system (CNS). They are widespread in the CNS and are involved in numerous physiological and pathological processes including synaptic plasticity, chronic pain and psychosis. Aberrant NMDAR activity also plays an important role in the neuronal loss associated with ischaemic insults and major degenerative disorders including Parkinson's and Alzheimer's disease. Agents that target and alter NMDAR function may, thus, have therapeutic benefit. Interestingly, NMDARs are endowed with multiple extracellular regulatory sites that recognize ions or small molecule ligands, some of which are likely to regulate receptor function in vivo. These allosteric sites, which differ from agonist-binding and channel-permeation sites, provide means to modulate, either positively or negatively, NMDAR activity. The present review focuses on allosteric modulation of NMDARs containing the NR2B subunit. Indeed, the NR2B subunit confers a particularly rich pharmacology with distinct recognition sites for exogenous and endogenous allosteric ligands. Moreover, NR2B-containing receptors, compared with other NMDAR subtypes, appear to contribute preferentially to pathological processes linked to overexcitation of glutamatergic pathways. The actions of extracellular H+, Mg2+, Zn2+, of polyamines and neurosteroids, and of the synthetic compounds ifenprodil and derivatives ('prodils') are presented. Particular emphasis is put upon the structural determinants and molecular mechanisms that underlie the effects exerted by these agents. A better understanding of how NR2B-containing NMDARs (and NMDARs in general) operate and how they can be modulated should help define new strategies to counteract the deleterious effects of dysregulated NMDAR activity.

  4. [A potential of selective androgen receptor modulator(SARM)for the therapy of osteoporosis].

    PubMed

    Yanase, Toshihiko

    2016-07-01

    In recent years, the drugs, which show anabolic, effect on bone and muscle without stimulating prostate has been developed. They show tissue-specific selective androgen actions and called selective androgen receptor modulators(SARMs). The development of drug targeting bone and muscle in male is very promising as a treatment tool for osteoporosis and sarcopenia in the near future. The clinical study is under going especially in the field of cachexia associated with cancer, but unfortunately there is no drug in the current market at present. The current situation of the development of SARMs will be reviewed.

  5. An alternative Fc gamma-receptor ligand: potential role in T-cell development.

    PubMed Central

    Sandor, M; Galon, J; Takacs, L; Tatsumi, Y; Mueller, A L; Sautes, C; Lynch, R G

    1994-01-01

    Fetal pre-T cells express low-affinity receptors for IgG (Fc gamma R) at a developmental stage prior to the rearrangement and expression of immunoglobulin genes. The present studies investigated the possible functional significance of Fc gamma R on fetal pre-T cells. Between 13 and 17 days of fetal development a subpopulation of T-cell receptor-, Thy-1+ thymocytes express for gamma R. The same cells contain mRNA for several forms of Fc gamma R (Fc gamma RII beta 1, beta 2, and Fc gamma RIII). Concurrently, a Pgp-1-, Thy-1-, surface-immunoglobulin- fetal thymic cell binds recombinant soluble Fc gamma R. In principle this cell can interact with the pre-T cells through this counter-receptor. To test this possibility anti-Fc gamma RII/III antibody (2.4G2) was injected into pregnant mice and then into their offspring for 6 wk postpartum. The injected antibody induced a slight increase in the proportion of CD4 or CD8 single-positive, alpha/beta T cells in the thymus. However, in fetal thymic cultures in the presence of 2.4G2 or the recombinant soluble Fc gamma R there was an accelerated differentiation of thymocytes to single-positive, CD3-bright, heat-stable antigen-dull, alpha/beta T cells. These experiments show that Fc gamma Rs are present on pre-T cells during early fetal thymic development, and that a non-IgG ligand of the Fc gamma R is expressed concurrently on Thy- fetal thymocytes. Furthermore, the presumed interaction of Fc gamma R and the alternative ligand(s) influences T-cell development. IgG binding could be an adapted function of Fc gamma Rs, and, as shown for many members of the Ig super family, these receptors may have originally served as cell-cell recognition/interaction molecules required for hematopoietic development. Images Fig. 2 PMID:7809135

  6. Cleavage of the thrombin receptor: identification of potential activators and inactivators.

    PubMed Central

    Parry, M A; Myles, T; Tschopp, J; Stone, S R

    1996-01-01

    The kinetic parameters were determined for the hydrolysis of a peptide based on the activation site of the thrombin receptor (residues 38-60) by thrombin and 12 other proteases. The kcat and Km values for the cleavage of this peptide (TR39-40) by thrombin were 107 s-1 and 1.3 microM; the kcat/Km of TR39-40 is among the highest observed for thrombin. A model is presented that reconciles the parameters for cleavage of the peptide with the concentration dependence of cellular responses to thrombin. Cleavage of TR39-40 was not specific for thrombin. The pancreatic proteases trypsin and chymotrypsin hydrolysed TR39-40 efficiently (kcat/Km > 10(6) M-1.s-1). Whereas trypsin cleaved TR39-40 at the thrombin activation site (Arg41-Ser42), chymotrypsin hydrolysed the peptide after Phe43. This chymotryptic cleavage would result in inactivation of the receptor. The efficient cleavage of TR39-40 by chymotrypsin (kcat/Km approximately 10(6) M-1.s-1) was predominantly due to a low Km value (2.8 microM). The proteases factor Xa, plasmin, plasma kallikrein, activated protein C and granzyme A also hydrolysed TR39-40 at the Arg41-Ser43 bond, but exhibited kcat/Km values that were at least 10(3)-fold lower than that observed with thrombin. Both tissue and urokinase plasminogen activators as well as granzyme B and neutrophil elastase were unable to cleave TR39-60 at appreciable rates. However, neutrophil cathepsin G hydrolysed the receptor peptide after Phe55. Like the chymotryptic cleavage, this cleavage would lead to inactivation of the receptor, but the cathepsin G reaction was markedly less efficient; the kcat/K(m) value was almost four orders of magnitude lower than that for thrombin. In addition to the above cleavage sites, a secondary site for thrombin and other arginine-specific proteases was identified at Arg46, but the cleavage at this site only occurred at very low rates and is unlikely to be significant in vivo. PMID:8947506

  7. Histamine h3 receptor antagonists potentiate methamphetamine self-administration and methamphetamine-induced accumbal dopamine release.

    PubMed

    Munzar, Patrik; Tanda, Gianluigi; Justinova, Zuzana; Goldberg, Steven R

    2004-04-01

    Methamphetamine administration increases brain levels of histamine and neuronal histamine attenuates several of methamphetamine's behavioral effects. The role of different subtypes of histamine receptors in this negative feedback, however, remains unclear. There is some evidence on possible involvement of histamine H3 receptors in these actions of methamphetamine. The aim of the present study was to evaluate the effects of two histamine H3 receptor antagonists, clobenpropit and thioperamide, on rewarding and neurochemical effects of methamphetamine utilizing three in vivo methodologies, drug self-administration, drug discrimination, and microdialysis in Sprague-Dawley rats. In rats self-administering methamphetamine intravenously under a fixed-ratio schedule, presession treatment with thioperamide (1.0-3.0 mg/kg, subcutaneous, s.c.) or clobenpropit (1.0-3.0 mg/kg, s.c.) potentiated the reinforcing effects of methamphetamine, as indicated by a dose-dependent increase in responding for a low 0.03 mg/kg dose of methamphetamine, that by itself failed to maintain responding above saline substitution levels, and a decrease in responding for a higher 0.06 mg/kg training dose of methamphetamine. In contrast, neither thioperamide nor clobenpropit treatment increased responding during saline substitution. In other rats trained to discriminate intraperitoneal (i.p.) injection of 1.0 mg/kg methamphetamine from i.p. injection of saline, both thioperamide and clobenpropit (0.3-3.0 mg/kg, s.c.) dose dependently increased methamphetamine-appropriate responding when administered with a low 0.3 mg/kg i.p. dose of methamphetamine, which by itself produced predominantly saline-appropriate responding. However, thioperamide and clobenpropit produced only saline-appropriate responding when administered with saline vehicle. Finally, thioperamide and clobenpropit potentiated methamphetamine-induced elevations in extracellular dopamine levels in the shell of the nucleus accumbens, but did

  8. Glutamate receptor δ2 associates with metabotropic glutamate receptor 1 (mGluR1), protein kinase Cγ, and canonical transient receptor potential 3 and regulates mGluR1-mediated synaptic transmission in cerebellar Purkinje neurons.

    PubMed

    Kato, Akihiko S; Knierman, Michael D; Siuda, Edward R; Isaac, John T R; Nisenbaum, Eric S; Bredt, David S

    2012-10-31

    Cerebellar motor coordination and cerebellar Purkinje cell synaptic function require metabotropic glutamate receptor 1 (mGluR1, Grm1). We used an unbiased proteomic approach to identify protein partners for mGluR1 in cerebellum and discovered glutamate receptor δ2 (GluRδ2, Grid2, GluΔ2) and protein kinase Cγ (PKCγ) as major interactors. We also found canonical transient receptor potential 3 (TRPC3), which is also needed for mGluR1-dependent slow EPSCs and motor coordination and associates with mGluR1, GluRδ2, and PKCγ. Mutation of GluRδ2 changes subcellular fractionation of mGluR1 and TRPC3 to increase their surface expression. Fitting with this, mGluR1-evoked inward currents are increased in GluRδ2 mutant mice. Moreover, loss of GluRδ2 disrupts the time course of mGluR1-dependent synaptic transmission at parallel fiber-Purkinje cells synapses. Thus, GluRδ2 is part of the mGluR1 signaling complex needed for cerebellar synaptic function and motor coordination, explaining the shared cerebellar motor phenotype that manifests in mutants of the mGluR1 and GluRδ2 signaling pathways.

  9. Breast density and parenchymal texture measures as potential risk factors for estrogen-receptor positive breast cancer

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Chen, Jinbo; Conant, Emily F.; Kontos, Despina

    2014-03-01

    Accurate assessment of a woman's risk to develop specific subtypes of breast cancer is critical for appropriate utilization of chemopreventative measures, such as with tamoxifen in preventing estrogen-receptor positive breast cancer. In this context, we investigate quantitative measures of breast density and parenchymal texture, measures of glandular tissue content and tissue structure, as risk factors for estrogen-receptor positive (ER+) breast cancer. Mediolateral oblique (MLO) view digital mammograms of the contralateral breast from 106 women with unilateral invasive breast cancer were retrospectively analyzed. Breast density and parenchymal texture were analyzed via fully-automated software. Logistic regression with feature selection and was performed to predict ER+ versus ER- cancer status. A combined model considering all imaging measures extracted was compared to baseline models consisting of density-alone and texture-alone features. Area under the curve (AUC) of the receiver operating characteristic (ROC) and Delong's test were used to compare the models' discriminatory capacity for receptor status. The density-alone model had a discriminatory capacity of 0.62 AUC (p=0.05). The texture-alone model had a higher discriminatory capacity of 0.70 AUC (p=0.001), which was not significantly different compared to the density-alone model (p=0.37). In contrast the combined density-texture logistic regression model had a discriminatory capacity of 0.82 AUC (p<0.001), which was statistically significantly higher than both the density-alone (p<0.001) and texture-alone regression models (p=0.04). The combination of breast density and texture measures may have the potential to identify women specifically at risk for estrogen-receptor positive breast cancer and could be useful in triaging women into appropriate risk-reduction strategies.

  10. Evolution of vertebrate transient receptor potential vanilloid 3 channels: opposite temperature sensitivity between mammals and western clawed frogs.

    PubMed

    Saito, Shigeru; Fukuta, Naomi; Shingai, Ryuzo; Tominaga, Makoto

    2011-04-01

    Transient Receptor Potential (TRP) channels serve as temperature receptors in a wide variety of animals and must have played crucial roles in thermal adaptation. The TRP vanilloid (TRPV) subfamily contains several temperature receptors with different temperature sensitivities. The TRPV3 channel is known to be highly expressed in skin, where it is activated by warm temperatures and serves as a sensor to detect ambient temperatures near the body temperature of homeothermic animals such as mammals. Here we performed comprehensive comparative analyses of the TRPV subfamily in order to understand the evolutionary process; we identified novel TRPV genes and also characterized the evolutionary flexibility of TRPV3 during vertebrate evolution. We cloned the TRPV3 channel from the western clawed frog Xenopus tropicalis to understand the functional evolution of the TRPV3 channel. The amino acid sequences of the N- and C-terminal regions of the TRPV3 channel were highly diversified from those of other terrestrial vertebrate TRPV3 channels, although central portions were well conserved. In a heterologous expression system, several mammalian TRPV3 agonists did not activate the TRPV3 channel of the western clawed frog. Moreover, the frog TRPV3 channel did not respond to heat stimuli, instead it was activated by cold temperatures. Temperature thresholds for activation were about 16 °C, slightly below the lower temperature limit for the western clawed frog. Given that the TRPV3 channel is expressed in skin, its likely role is to detect noxious cold temperatures. Thus, the western clawed frog and mammals acquired opposite temperature sensitivity of the TRPV3 channel in order to detect environmental temperatures suitable for their respective species, indicating that temperature receptors can dynamically change properties to adapt to different thermal environments during evolution.

  11. Transmembrane potential polarization, calcium influx, and receptor conformational state modulate the sensitivity of the imidacloprid-insensitive neuronal insect nicotinic acetylcholine receptor to neonicotinoid insecticides.

    PubMed

    Bodereau-Dubois, Béatrice; List, Olivier; Calas-List, Delphine; Marques, Olivier; Communal, Pierre-Yves; Thany, Steeve H; Lapied, Bruno

    2012-05-01

    Neonicotinoid insecticides act selectively on insect nicotinic acetylcholine receptors (nAChRs). Recent studies revealed that their efficiency was altered by the phosphorylation/dephosphorylation process and the intracellular signaling pathway involved in the regulation of nAChRs. Using whole-cell patch-clamp electrophysiology adapted for dissociated cockroach dorsal unpaired median (DUM) neurons, we demonstrated that intracellular factors involved in the regulation of nAChR function modulated neonicotinoid sensitivity. DUM neurons were known to express two α-bungarotoxin-insensitive nAChR subtypes: nAChR1 and nAChR2. Whereas nAChR1 was sensitive to imidacloprid, nAChR2 was insensitive to this insecticide. Here, we demonstrated that, like nicotine, acetamiprid and clothianidin, other types of neonicotinoid insecticides, acted as agonists on the nAChR2 subtype. Using acetamiprid, we revealed that both steady-state depolarization and hyperpolarization affected nAChR2 sensitivity. The measurement of the input membrane resistance indicated that change in the acetamiprid-induced agonist activity was related to the receptor conformational state. Using cadmium chloride, ω-conotoxin GVIA, and (R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-acetamide (LOE 908), we found that inhibition of calcium influx through high voltage-activated calcium channels and transient receptor potential γ (TRPγ) activated by both depolarization and hyperpolarization increased nAChR2 sensitivity to acetamiprid. Finally, using N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W7), forskolin, and cAMP, we demonstrated that adenylyl cyclase sensitive to the calcium/calmodulin complex regulated internal cAMP concentration, which in turn modulated TRPγ function and nAChR2 sensitivity to acetamiprid. Similar TRPγ-induced modulatory effects were also obtained when clothianidin was tested. These findings bring insights into the signaling pathway modulating

  12. Transmembrane potential polarization, calcium influx, and receptor conformational state modulate the sensitivity of the imidacloprid-insensitive neuronal insect nicotinic acetylcholine receptor to neonicotinoid insecticides.

    PubMed

    Bodereau-Dubois, Béatrice; List, Olivier; Calas-List, Delphine; Marques, Olivier; Communal, Pierre-Yves; Thany, Steeve H; Lapied, Bruno

    2012-05-01

    Neonicotinoid insecticides act selectively on insect nicotinic acetylcholine receptors (nAChRs). Recent studies revealed that their efficiency was altered by the phosphorylation/dephosphorylation process and the intracellular signaling pathway involved in the regulation of nAChRs. Using whole-cell patch-clamp electrophysiology adapted for dissociated cockroach dorsal unpaired median (DUM) neurons, we demonstrated that intracellular factors involved in the regulation of nAChR function modulated neonicotinoid sensitivity. DUM neurons were known to express two α-bungarotoxin-insensitive nAChR subtypes: nAChR1 and nAChR2. Whereas nAChR1 was sensitive to imidacloprid, nAChR2 was insensitive to this insecticide. Here, we demonstrated that, like nicotine, acetamiprid and clothianidin, other types of neonicotinoid insecticides, acted as agonists on the nAChR2 subtype. Using acetamiprid, we revealed that both steady-state depolarization and hyperpolarization affected nAChR2 sensitivity. The measurement of the input membrane resistance indicated that change in the acetamiprid-induced agonist activity was related to the receptor conformational state. Using cadmium chloride, ω-conotoxin GVIA, and (R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-acetamide (LOE 908), we found that inhibition of calcium influx through high voltage-activated calcium channels and transient receptor potential γ (TRPγ) activated by both depolarization and hyperpolarization increased nAChR2 sensitivity to acetamiprid. Finally, using N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W7), forskolin, and cAMP, we demonstrated that adenylyl cyclase sensitive to the calcium/calmodulin complex regulated internal cAMP concentration, which in turn modulated TRPγ function and nAChR2 sensitivity to acetamiprid. Similar TRPγ-induced modulatory effects were also obtained when clothianidin was tested. These findings bring insights into the signaling pathway modulating

  13. Deramciclane improves object recognition in rats: potential role of NMDA receptors.

    PubMed

    Kertész, Szabolcs; Kapus, Gábor; Gacsályi, István; Lévay, György

    2010-02-01

    The cognition-enhancing properties of deramciclane (N,N-dimethyl-2-([(1R,4R,6S)-1,7,7-trimethyl-6-phenyl-6-bicyclo[2.2.1]heptanyl]oxy)ethanamine) and memantine (3,5-dimethyl-tricyclo[3.3.1.1(3,7)]decylamine-3,5-dimethyladamantan-1-amine) were evaluated in the novel object recognition (OR) test in the rat, while their effect in comparison with other N-methyl-D-aspartate (NMDA) receptor blockers such us MK-801 ([+]-5-methyl-10,11-dihydro-5H-dibenzocyclohepten-5,10-imine maleate) and CPP ([+/-]-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid) on NMDA-evoked spreading depression (SD) was investigated in the chicken retina, in vitro. In the OR test, pretreatment of rats with either deramciclane (30 mg/kg p.o.) or memantine (10 and 30 mg/kg, p.o.) resulted in preference for the novel object, compared to the familiar one, indicating procognitive activity of the compounds. In the in vitro studies memantine (10-30 M), or deramciclane (30-100 M) as well as CPP (0.1-1 M), MK-801 (0.3-1 M), concentration-dependently inhibited NMDA evoked SD. Furthermore, the inhibitory effect of memantine, deramciclane and MK-801 was activity-dependent. These results support the role of NMDA receptors in the procognitive effect of deramciclane.

  14. Jasmonate perception by inositol-phosphate-potentiated COI1-JAZ co-receptor

    SciTech Connect

    Sheard, Laura B; Tan, Xu; Mao, Haibin; Withers, John; Ben-Nissan, Gili; Hinds, Thomas R; Kobayashi, Yuichi; Hsu, Fong-Fu; Sharon, Michal; Browse, John; He, Sheng Yang; Rizo, Josep; Howe, Gregg A; Zheng, Ning

    2011-11-07

    Jasmonates are a family of plant hormones that regulate plant growth, development and responses to stress. The F-box protein CORONATINE INSENSITIVE 1 (COI1) mediates jasmonate signalling by promoting hormone-dependent ubiquitylation and degradation of transcriptional repressor JAZ proteins. Despite its importance, the mechanism of jasmonate perception remains unclear. Here we present structural and pharmacological data to show that the true Arabidopsis jasmonate receptor is a complex of both COI1 and JAZ. COI1 contains an open pocket that recognizes the bioactive hormone (3R,7S)-jasmonoyl-l-isoleucine (JA-Ile) with high specificity. High-affinity hormone binding requires a bipartite JAZ degron sequence consisting of a conserved {alpha}-helix for COI1 docking and a loop region to trap the hormone in its binding pocket. In addition, we identify a third critical component of the jasmonate co-receptor complex, inositol pentakisphosphate, which interacts with both COI1 and JAZ adjacent to the ligand. Our results unravel the mechanism of jasmonate perception and highlight the ability of F-box proteins to evolve as multi-component signalling hubs.