Transient Receptor Potential Vanilloid Subtype Research Articles

Novel polygodial analogs P3 and P27: Efficacious therapeutic agents disrupting mitochondrial function in oral squamous cell carcinoma.

Polygodial, a drimane sesquiterpenoid dialdehyde isolated as a pungent component of the water pepper Persicaria hydropiper, exhibits antifeedant, antimicrobial, anti-inflammatory and anticancer effects. Polygodial also activates transient receptor potential vanilloid subtype 1 (TRPV1) channels. Previously, we described the synthesis of a C12-Wittig derivative of polygodial, termed P3, with significant antiproliferative effects against multiple cancer types including oral squamous cell carcinoma (OSCC). In the present study, a more potent derivative, P27, with superior anti-proliferative effects in vitro and antitumor effects in Cal-27 derived xenografts is described. Polygodial, P3, and P27 all significantly decreased OSCC tumor growth, with P27 being equipotent with polygodial and P3 being the least efficacious. However, neither analog elicited the adverse effect observed with polygodial: Profound transient inflammation. Although P3 and P27 pharmacophores are based on polygodial, novel effects on OSCC cell cycle distribution were identified and shared anticancer effects that are independent of TRPV1 activity were observed. Polygodial elicits an S-phase block, whereas P3 and P27 lead to G2/M phase arrest. Pretreatment of OSCC cells with the TRPV1 antagonist capsazepine does not affect the antiproliferative activity of P3 or P27, indicating that TRPV1 interactions do not regulate OSCC cell proliferation. Indeed, calcium imaging studies identified that the analogs neither activate nor antagonize TRPV1. Behavioral studies using a rat model for orofacial pain confirmed that these analogs fail to induce nocifensive responses, indicating that they are non-noxious in vivo. All compounds induced a significant concentration-dependent decrease in the mitochondrial transmembrane potential and corresponding apoptosis. Considering that P27 is equipotent to polygodial with no TRPV1-associated adverse effects, P27 may serve as an efficacious novel therapy for OSCC.

A9216 Deficiency of transient receptor potential vanilloid subtype 1 and uncoupling protein 1 in brown fat causes obesity-associated hypertension

A9216 Deficiency of transient receptor potential vanilloid subtype 1 and uncoupling protein 1 in brown fat causes obesity-associated hypertension

Oleoylethanolamide and Palmitoylethanolamide Protect Cultured Cortical Neurons Against Hypoxia.

Introduction: Perinatal hypoxic–ischemic (HI) encephalopathy is defined as a neurological syndrome where the newborn suffers from acute ischemia and hypoxia during the perinatal period. New therapies are needed. The acylethanolamides, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), possess neuroprotective properties, and they could be effective against perinatal HI. These lipid mediators act through peroxisome proliferator-activated receptors subtype α (PPARα), or transient receptor potential vanilloid (TRPV), such as TRPV subtype 1 and 4.Materials and Methods: The objectives of this study were to discern: (1) the neuroprotective role of OEA and PEA in parietotemporal cortical neurons of newborn rats and mice subjected to hypoxia, and (2) the role of the receptors, PPARα, TRPV1, and TRPV4, in neuroprotective effects. Cell culture of cortical neurons and the lactate dehydrogenase assay was carried out. The role of receptors was discerned by using selective antagonist and agonist ligands, as well as knockout (KO) PPARα mice.Results: The findings indicate that OEA and PEA exert neuroprotective effects on cultured cortical neurons subjected to a hypoxic episode. These protective effects are not mediated by the receptors, PPARα, TRPV1, or TRPV4, because neither PPARα KO mice nor receptor ligands significantly modify OEA and PEA-induced effects. Blocking TRPV4 with RN1734 is neuroprotective per se, and cotreatment with OEA and PEA is able to enhance neuroprotective effects of the acylethanolamides. Since stimulating TRPV4 was devoid of effects on OEA and PEA-induced protective effects, effects of RN1734 cotreatment seem to be a consequence of additive actions.Conclusion: The lipid mediators, OEA and PEA, exert neuroprotective effects on cultured cortical neurons subjected to hypoxia. Coadministration of OEA or PEA, and the TRPV4 antagonist RN1734 is able to enhance neuroprotective effects. These in vitro results could be of utility for developing new therapeutic tools against perinatal HI.

Design, synthesis, and in silico studies of novel eugenyloxy propanol azole derivatives having potent antinociceptive activity and evaluation of their β-adrenoceptor blocking property.

The design, synthesis, antinociceptive and β-adrenoceptor blocking activities of several eugenyloxy propanol azole derivatives have been described. In this synthesis, the reaction of eugenol with epichlorohydrin provided adducts 3 and 4 which were N-alkylated by diverse azoles to obtain the eugenyloxy propanol azole analogues in good yields. Adducts 3 and 4 were also reacted with azide ion to obtain the corresponding azide 6. The 'Click' Huisgen cycloaddition reaction of 6 with diverse alkynes afforded the title compounds in good yields. The synthesized eugenyloxy propanol azole derivatives were in vivo studied for the acute antinociception on male Spargue Dawley rats using tail-flick test. Compounds 5f, 5g, 7b and 11a exhibited potent analgesic properties in comparison with eugenol as a standard drug. In addition, all compounds were ex vivo tested for β-adrenoceptor blocking properties on isolated left atrium of male rats which exhibited partial antagonist or agonist behaviour compared to the standard drugs. The molecular docking study on the binding site of transient receptor potential vanilloid subtype 1 (TRPV1) has indicated that like capsaicin, eugenyloxy propanol azole analogues exhibited the strong affinity to bind at site of TPRV1 in a "tail-up, head-down" conformation and the presence of triazolyl moieties has played undeniable role in durable binding of these ligands to TRPV1. The in silico pharmacokinetic profile, drug likeness and toxicity predictions carried out for all compounds determined that 5g can be considered as potential antinociceptive drug candidate for future research.

Gastrointestinal Spice Sensors and Their Functions

Capsaicin is a constituent of chili pepper, and induces the burning sensation on the tongue. The site of action for capsaicin has been discovered as transient receptor potential vanilloid receptor subtype 1 (TRPV1) that resides on the membranes of pain- and heat-sensing primary afferent nerves. The immunohistochemical study on the stomach revealed that nerve fibers expressing TRPV1 exist along gastric glands in the mucosa, around blood vessels in the submucosa, in the myenteric plexus, and in the smooth muscle layers. High numbers of TRPV1-immunoreactive axons were observed in the rectum and distal colon. Therefore, capsaicin stimulates TRPV1 not only on the tongue but also in the gut. In this review, the mechanism of gastrointestinal mucosal defense enhanced by capsaicin was summarized. TRPV1 plays a protective role in gastrointestinal mucosal defensive mechanism. Hypersensitivity of afferent fibers occurs during gastrointestinal inflammation. Abnormalities of primary afferent nerve fibers are strongly associated with the visceral hypersensitive state in inflammatory bowel disease (IBD). The alteration of TRPV1 channels in mucosa contributes to the visceral hypersensitivity in colitis model mice. TRPV1-expressing neurons in the gut are thought to be extrinsic sensory afferent neurons that operate to maintain gastrointestinal functions under physiological and inflammatory states.

Decreased Expression of TRPV4 Channels in HEI-OC1 Cells Induced by High Glucose Is Associated with Hearing Impairment.

PurposePrevious reports have shown that hyperglycemia-induced inhibition of transient receptor potential vanilloid sub type 4 (TRPV4), a transient receptor potential ion channel, affects the severity of hearing impairment (HI). In this study, we explored the role of TRPV4 in HI using HEI-OC1 cells exposed to high glucose (HG).Materials and MethodsHEI-OC1 cells were cultured in a HG environment (25 mM D-glucose) for 48 hours, and qRT-PCR and Western blotting were used to analyze the expression of TRPV4 at the mRNA and protein level. TRPV4 agonist (GSK1016790A) or antagonist (HC-067047) in cultured HEI-OC1 cells was used to obtain abnormal TRPV4 expression. Functional TRPV4 activity was assessed in cultured HEI-OC1 cells using the MTT assay and a cell death detection ELISA.ResultsTRPV4 agonists exerted protective effects against HG-induced HI, as evidenced by increased MTT levels and inhibition of apoptosis in HEI-OC1 cells. TRPV4 overexpression significantly increased protein levels of phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK), while TRPV4 antagonists had the opposite effect. Our results indicated that TRPV4 is a hyperglycemia-related factor that can inhibit cell proliferation and promote cell apoptosis by activating the MAPK signaling pathway in HEI-OC1 cells.ConclusionOur results show that the overexpression of TRPV4 can attenuate cell death in HEI-OC1 cells exposed to HG.

Involvement of mGluR5 and TRPV1 in visceral nociception in a rat model of uterine cervical distension.

Metabotropic glutamate receptor 5 (mGluR5) and transient receptor potential vanilloid subtype 1 (TRPV1) have been shown to play critical roles in the transduction and modulation of cutaneous nociception in the central nervous system. However, little is known regarding the possible involvement of mGluR5 and TRPV1 in regulating visceral nociception from the uterine cervix. In this study, we used a rat model of uterine cervical distension to examine the effects of noxious stimuli to the uterine cervix on expression of spinal mGluR5 and TRPV1. Our findings included the following: (1) uterine cervical distension resulted in a stimulus-dependent increase in electromyographic, spinal c-Fos signal, and expression of mGluR5 and TRPV1 in the spinal cord; (2) intrathecal administration of the mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyri-dine significantly reduced the increased TRPV1 and c-Fos expression induced by uterine cervical distension; (3) the TRPV1 inhibitor SB-366791 inhibited increased spinal c-Fos expression but had no effect on the expression of mGluR5 in response to uterine cervical distension. Our findings indicate that the spinal mGluR5-TRPV1 pathway modulates nociceptive transmission in uterine cervical distension-induced pathological visceral pain.

Treatment with methyl-β-cyclodextrin prevents mechanical allodynia in resiniferatoxin neuropathy in a mouse model.

ABSTRACTSpecialized microdomains which have cholesterol-rich membrane regions contain transient receptor potential vanilloid subtype 1 (TRPV1) are involved in pain development. Our previous studies have demonstrated that the depletion of prostatic acid phosphatase (PAP) – a membrane-bound ectonucleotidase ­– and disordered adenosine signaling reduce the antinociceptive effect. The role of membrane integrity in the PAP-mediated antinociceptive effect in small-fiber neuropathy remains unclear, especially with respect to whether TRPV1 and PAP are colocalized in the same microdomain which is responsible for PAP-mediated antinociception. Immunohistochemistry was conducted on the dorsal root ganglion to identify the membrane compositions, and pharmacological interventions were conducted using methyl-β-cyclodextrin (MβC) – a membrane integrity disruptor that works by depleting cholesterol – in pure small-fiber neuropathy with resiniferatoxin (RTX). Immunohistochemical evidence indicated that TRPV1 and PAP were highly colocalized with flotillin 1 (66.7%±9.7%) and flotillin 2 (73.7%±6.0%), which reside in part in the microdomain. MβC mildly depleted PAP, which maintained the ability to hydrolyze phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and delayed the development of mechanical allodynia. MβC treatment had no role in thermal transduction and neuronal injury following RTX neuropathy. In summary, this study demonstrated the following: (1) membrane cholesterol depletion preserves PAP-mediated antinociception through PI(4,5)P2 hydrolysis and (2) pain hypersensitivity that develops after TRPV1(+) neuron depletion-mediated neurodegeneration following RTX neuropathy is attributable to the downregulation of PAP analgesic signaling.

TRPV4 is involved in irisin-induced endothelium-dependent vasodilation

Irisin, an exercise-induced myokine, induces conversion of white into brown adipocytes, promoting mitochondrial biogenesis and energy expenditure. Irisin has a vascular protective effect on endothelial function in animals, including humans. Defects in irisin signaling pathways result in endothelial dysfunction in obesity and diabetes. However, the mechanisms underlying the effects of irisin on endothelial function have not been elucidated. Transient receptor potential vanilloid subtype 4 (TRPV4) channels are one of the most important Ca2+-permeable cation channels in vascular endothelial cells. In this study, we hypothesized that irisin may induce endothelium-dependent vasodilation by activating Ca2+ influx into endothelial cells via TRPV4 channels. In primary cultured rat mesenteric artery endothelial cells, irisin caused an increase in [Ca2+]i due to extracellular Ca2+ influx rather than release from Ca2+ stores. Moreover, irisin-induced increases in [Ca2+]i were completely abolished by a TRPV4 inhibitor. In addition, irisin induced endothelium-dependent vasodilation of rat mesenteric arteries. However, irisin had no effect on endothelium-independent vasodilation. Furthermore, irisin-induced vasodilation was fully abolished in the presence of a TRPV4 inhibitor, indicating the involvement of TRPV4 channels in endothelium-dependent vasodilation. This study provides the first evidence that irisin-induced endothelium-dependent vasodilation is related to the stimulation of extracellular Ca2+ influx via TRPV4 channels in rat mesenteric arteries.

Dual contribution of TRPV4 antagonism in the regulatory effect of vasoinhibins on blood-retinal barrier permeability: diabetic milieu makes a difference

Breakdown of the blood-retinal barrier (BRB), as occurs in diabetic retinopathy and other chronic retinal diseases, results in vasogenic edema and neural tissue damage, causing vision loss. Vasoinhibins are N-terminal fragments of prolactin that prevent BRB breakdown during diabetes. They modulate the expression of some transient receptor potential (TRP) family members, yet their role in regulating the TRP vanilloid subtype 4 (TRPV4) remains unknown. TRPV4 is a calcium-permeable channel involved in barrier permeability, which blockade has been shown to prevent and resolve pulmonary edema. We found TRPV4 expression in the endothelium and retinal pigment epithelium (RPE) components of the BRB, and that TRPV4-selective antagonists (RN-1734 and GSK2193874) resolve BRB breakdown in diabetic rats. Using human RPE (ARPE-19) cell monolayers and endothelial cell systems, we further observed that (i) GSK2193874 does not seem to contribute to the regulation of BRB and RPE permeability by vasoinhibins under diabetic or hyperglycemic-mimicking conditions, but that (ii) vasoinhibins can block TRPV4 to maintain BRB and endothelial permeability. Our results provide important insights into the pathogenesis of diabetic retinopathy that will further guide us toward rationally-guided new therapies: synergistic combination of selective TRPV4 blockers and vasoinhibins can be proposed to mitigate diabetes-evoked BRB breakdown.

TDAG8, TRPV1, and ASIC3 involved in establishing hyperalgesic priming in experimental rheumatoid arthritis

Rheumatoid arthritis (RA), characterized by chronic inflammation of synovial joints, is often associated with ongoing pain and increased pain sensitivity. High hydrogen ion concentration (acidosis) found in synovial fluid in RA patients is associated with disease severity. Acidosis signaling acting on proton-sensing receptors may contribute to inflammation and pain. Previous studies focused on the early phase of arthritis (<5 weeks) and used different arthritis models, so elucidating the roles of different proton-sensing receptors in the chronic phase of arthritis is difficult. We intra-articularly injected complete Freund’s adjuvant into mice once a week for 4 weeks to establish chronic RA pain. Mice with knockout of acid-sensing ion channel 3 (ASIC3) or transient receptor potential/vanilloid receptor subtype 1 (TRPV1) showed attenuated chronic phase (>6 weeks) of RA pain. Mice with T-cell death-associated gene 8 (TDAG8) knockout showed attenuated acute and chronic phases of RA pain. TDAG8 likely participates in the initiation of RA pain, but all three genes, TDAG8, TRPV1, and ASIC3, are essential to establish hyperalgesic priming to regulate the chronic phase of RA pain.

Construction of Prediction Models for the Transient Receptor Potential Vanilloid Subtype 1 (TRPV1)-Stimulating Activity of Ginger and Processed Ginger Based on LC-HRMS Data and PLS Regression Analyses.

To construct a model formula to evaluate the thermogenetic effect of ginger (Zingiber officinale Roscoe) from the ingredient information, we established transient receptor potential vanilloid subtype 1 (TRPV1)-stimulating activity prediction models by using a partial least-squares projections to latent structures (PLS) regression analysis in which the ingredient data from liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and the stimulating activity values for TRPV1 receptor were used as explanatory and objective variables, respectively. By optimizing the peak extraction condition of the LC-HRMS data and the data preprocessing parameters of the PLS regression analysis, we succeeded in the construction of a TRPV1-stimulating activity prediction model with high precision ability. We then searched for the components responsible for the TRPV1-stimulating activity by analyzing the loading plot and s-plot of the model, and we identified [6]-gingerol (1) and hexahydrocurcumin (3) as TRPV1-stimulating activity components.

Heterogeneity of TRPV4 Expression and Function in Endothelial Cells of Different Vascular Beds

IntroductionThe ubiquitously expressed calcium channel transient receptor potential vanilloid subtype 4 (TRPV4) has been implicated in various endothelial functions. Specifically, TRPV4 activation triggers endothelial barrier failure. In the lung, TRPV4‐mediated pulmonary edema formation has been reported in response to various triggers including acid aspiration and positive pressure ventilation. Thus, TRPV4 is a promising target for preventing or treating lung injury, but its ubiquitous expression requires investigating potential off‐target effects during therapeutic modulation.MethodsThe present study is working toward this aim by comparing TRPV4 expression and function in human endothelial cells from five different vascular beds: pulmonary (HPMEC), cerebral (HCMEC) and adipose (HAMEC) microvascular as well as pulmonary artery (HPAEC) and coronary artery (HCAEC). Response to the TRPV4 agonist GSK1016790A was assessed by ratiometric Fura‐2 imaging of intracellular calcium concentration [Ca2+]i, measuring transendothelial electrical resistance (TEER), and fluorescence imaging of cytoskeletal actin and VE‐cadherin. TRPV4 protein expression was densitometrically quantified by Western blot, normalized to GAPDH for comparison between the five cell types.ResultsAgonist treatment increased [Ca2+]i and decreased TEER in all endothelial cell types studied, while vehicle (dimethylsulfoxide) had no effect. Interestingly, there was strong inverse correlation between the [Ca2+]i response and decrease in TEER amongst the three microvascular cell types, HPMEC, HAMEC and HCMEC, with the [Ca2+]i and reduction of TEER increasing in the order HPMEC &lt; HAMEC &lt; HCMEC. This effect was corroborated by fluorescence imaging that showed TRPV4 agonism caused intercellular adherens junctions to become disrupted and gaps to form within the endothelial monolayer. In some cases, endothelial cells significantly contracted and became rounded, losing surface VE‐cadherin and forming actin stress fibers. The degree of this effect varied between microvascular cells, again in the increasing order HPMEC &lt; HAMEC &lt; HCMEC. Furthermore, these observations correlated with quantification of Western blot showing HCMECs had highest expression of TRPV4 protein. Notably, while macrovascular HPAECs and HCAECs showed quantitatively similar responses as microvascular endothelial cells, they did not fit the linear regression between [Ca2+]i and TEER response.ConclusionThese results demonstrate quantitative heterogeneity in endothelial TRPV4 function in different vascular beds, and identify TRPV4 as a major regulator of microvascular endothelial cell permeability, while confirming the established differences in barrier function between micro‐ and macrovascular endothelial cells.Support or Funding InformationCanadian Institutes of Health Research (CIHR)Ontario Research Fund (ORF)

Capsaicin prevents degeneration of dopamine neurons by inhibiting glial activation and oxidative stress in the MPTP model of Parkinson\u2019s disease

The effects of capsaicin (CAP), a transient receptor potential vanilloid subtype 1 (TRPV1) agonist, were determined on nigrostriatal dopamine (DA) neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson’s disease (PD). The results showed that TRPV1 activation by CAP rescued nigrostriatal DA neurons, enhanced striatal DA functions and improved behavioral recovery in MPTP-treated mice. CAP neuroprotection was associated with reduced expression of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and reactive oxygen species/reactive nitrogen species from activated microglia-derived NADPH oxidase, inducible nitric oxide synthase or reactive astrocyte-derived myeloidperoxidase. These beneficial effects of CAP were reversed by treatment with the TRPV1 antagonists capsazepine and iodo-resiniferatoxin, indicating TRPV1 involvement. This study demonstrates that TRPV1 activation by CAP protects nigrostriatal DA neurons via inhibition of glial activation-mediated oxidative stress and neuroinflammation in the MPTP mouse model of PD. These results suggest that CAP and its analogs may be beneficial therapeutic agents for the treatment of PD and other neurodegenerative disorders that are associated with neuroinflammation and glial activation-derived oxidative damage.

Safety, Pharmacokinetics, and Pharmacodynamics Study in Healthy Subjects of Oral NEO6860, a Modality Selective Transient Receptor Potential Vanilloid Subtype 1 Antagonist

This first in human study on NEO6860, showed that an antagonist of TRPV1, blocking only the activation by capsaicin has been identified. This finding paves the way for the development of a new powerful analgesic for many pain conditions, without the fear of the side effects observed with previous TRPV1 antagonists.

Antiallodynic effect of intrathecal resiniferatoxin on neuropathic pain model of chronic constriction injury

Injuries and/or dysfunctions in the somatosensory system can lead to neuropathic pain. Transient receptor potential vanilloid sub‑type 1 (TRPV1) play an important role in the development of allodynia and hyperalgesia following injury and the ensuing inflammatory conditions. Resiniferatoxin (RTX) is an ultrapotent synthetic TRPV1 agonist and many different administration routes are available for different mechanisms and different effects. RTX is used intraperitonially as amodel of neuropathic pain or epidurally and topically to produce prolonged analgesic effects. However, the use of RTX is controversial because its neurotoxicity and margin of safety have not been addressed adequately. The present study evaluates the effect of intrathecal RTX on the induction and allodynia behavior of animals submitted to neuropathic pain by chronic constriction injury (CCI). 160 Swiss mice were randomly distributed into two groups: intrathecal pre‑treatment group (PRE) aiming the effect in induction of allodynia and late intrathecal treatment group (POST) to evaluate the antiallodynic effect of the RTX on mechanical nociceptive threshold evaluated by the Von Frey hair filaments. Additionally, we evaluated the expression of TRPV1 in dorsal root ganglia (DRG) by western blotting after PRE‑ and POST‑treatment with RTX. Our results showed that the CCI mice developed prolonged mechanical allodynia‑like behavior in ipsilateral paw after surgery up to 24hours. The PRE‑ and POST‑treatment groups presented significant antiallodynic effects in ipsilateral paw for 24hours. Only the POST‑treatment group showed asignificant reduction of expression of the TRPV1 receptor after CCI. The presented data demonstrated that both PRE‑ and POST‑treatment with RTX given intrathecally produced potent antiallodynic activities in CCI mice and that POST‑treatment can reduce TRPV1 expression in DRG, suggesting that POST‑treatment RTX can revert central sensitization and its associated allodynia.

Decreases in 15-lipoxygenase metabolites in Olmsted syndrome model rats

BackgroundOlmsted syndrome (OS) is a congenital dermatosis characterized by palmoplantar keratoderma and periorificial keratotic plaque. TRPV3 (transient receptor potential vanilloid subtype 3) encodes a thermosensitive Ca2+ channel and is the causative gene of OS. However, the molecular mechanism that causes the pathological development of OS is unclear. ObjectiveWe aimed to investigate the molecular mechanisms underlying OS pathology from the perspective of lipid metabolism. MethodsComprehensive lipidomics and microarray analyses were conducted on tissue samples from a non-lesional skin area of OS model rats (Ht rats) and from wild type (WT) rats as the control. ResultsInfiltration of leukocytes such as eosinophils and neutrophils and an increase in the fibrotic region were detected in the unaffected skin area of Ht rats compared with the WT rats. Among about 600 lipid species examined, the levels of 15-lipoxygenase (LOX) metabolites, the precursors of anti-inflammatory and pro-resolving lipid mediators, and dihydroceramides decreased by ≥16-fold in Ht rats compared with WT rats. Consistent with the decreases in the 15-LOX metabolites, expression levels of the genes that encode the 15-LOXs, Alox15 and Alox15b, were largely reduced. Conversely, increased expression levels were detected of Il36b, Ccl20, Cxcl1, and Cxcl2, which encode cytokines/chemokines, and S100a8 and S100a9, which encode the Ca2+ binding proteins that are implicated in epidermal proliferation. ConclusionThe pro-inflammatory state in the unaffected skin of Ht rats caused by decreases in 15-LOX metabolites and increases in cytokines/chemokines may contribute to the pathogenesis of OS.

Pharmacological Properties of Propiverine Contribute to Improving Lower Urinary Tract Dysfunctions in Rats with Spinal Cord Injuries.

Patients with spinal cord injury (SCI) usually develop lower urinary tract dysfunctions, including detrusor overactivity which is also known to be a risk factor for upper urinary tract dysfunction. Antimuscarinic agents, such as propiverine, have been used clinically for the treatment of detrusor overactivity. Also, propiverine has been known to possess antagonistic activity against L-type Ca2+ channels and transient receptor potential vanilloid subtype 1 (TRPV1), in addition to activity against muscarinic receptors. These mechanisms of action may contribute to improving detrusor overactivity in SCI. We therefore investigated the effects of antagonists of these mechanisms on non-voiding contraction (NVC) in SCI rats that are similar to clinical cases of detrusor overactivity, and considered whether these action mechanisms contribute to the incidence of NVC in SCI. Cystometry was performed in rats 4 weeks after spinal transection. Urinary functions were evaluated before and after intravenous administration of propiverine and specific antagonists for muscarinic receptors (atropine), L-type Ca2+ channels (verapamil), and TRPV1 (capsazepine). Propiverine markedly decreased the amplitude pressure of NVC in SCI rats, which was partially inhibited by atropine. Verapamil also suppressed the amplitude pressure of NVC to the same degree as propiverine. NVC disappeared almost completely after C-fiber desensitization, although capsazepine exerted no evident effects. These findings suggest that muscarinic receptors, L-type Ca2+ channels, and C-fiber afferent nerves contribute to the incidence of detrusor overactivity in SCI, and a drug that has multiple antagonistic effects, such as propiverine, is very effective for the treatment of lower urinary tract dysfunctions in SCI.

TRPV1 antagonist JNJ-39439335 (mavatrep) demonstrates proof of pharmacology in healthy men: a first-in-human, double-blind, placebo-controlled, randomized, sequential group study.

This double-blind, randomized, placebo-controlled, sequential group, phase 1 study was designed to assess in healthy men, the safety, tolerability, pharmacokinetics, and translational pharmacodynamics of JNJ-39439335 (mavatrep), a transient receptor potential vanilloid subtype 1 antagonist; it was preceded by a translational preclinical study which assessed the ability of JNJ-39439335 to block capsaicin-induced flare in rats, providing predictive pharmacokinetic and pharmacodynamic data that informed the subsequent phase 1 clinical study. The clinical study consisted of 2 parts: part 1 assessed pharmacokinetics and pharmacodynamics, including heat pain detection threshold and heat pain tolerance, of JNJ-39439335, and part 2 assessed pharmacodynamic effect of JNJ-39439335 on capsaicin-induced flare and sensory testing on naïve and UVB-sensitized skin in humans. Plasma concentrations of JNJ-39439335 peaked at approximately 2 to 4 hours postdose, then declined multiexponentially, with a prolonged terminal phase (half-life: 30-86 hours). Renal clearance of JNJ-39439335 was negligible. JNJ-39439335 treatment resulted in clear, consistent dose-related increases in heat pain detection threshold, heat pain tolerance, and heat pain latency. JNJ-39439335 reduced the capsaicin-induced flare area and flare intensity, with complete blocking observed in the 50-mg dose group at 144 hours postdose. This was consistent with the capsaicin flare results observed with JNJ-39439335 in rats. The most common adverse events observed in the clinical study were related to increases in body temperature after JNJ-39439335 treatment; these were predominately mild to moderate in severity with no evidence of exposure dependence up to 225 mg. JNJ-39439335 was well tolerated at single doses up to 225 mg, recommending its suitability for further clinical development.

TRPV4 mediates afferent pathways in the urinary bladder. A spinal c-fos study showing TRPV1 related adaptations in the TRPV4 knockout mouse.

The role of transient receptor potential vanilloid subtype 4 (TRPV4) channels in urinary bladder afferent neural pathways was investigated using spinal c-fos measurements in mice. Anesthetized wild type and TRPV4 knockout (−/−) mice underwent noxious bladder distention and treatment with either intravesical instillation with lipopolysaccharide (LPS), or the TRPV1 agonist resiniferatoxin (RTX), vehicle or an intraperitoneal injected TRPV4 antagonist (HC067047). Mice underwent paraformaldehyde perfusion for rapid fixation and L6-S1 spinal cord sections were removed followed by immunohistochemical staining for c-fos. A number of c-fos expressing neurons in the dorsal horns of L6-S1 spinal cord transections were quantified. Groups were compared using univariate ANOVA. Even with the absence of bladder inflammation on H&E, the TRPV4 −/− mice still have a significant twofold higher c-fos expression (n = 39, SD 2) after noxious bladder distention compared to wild type mice (n = 20, SD 3). A twofold increase in c-fos expression was observed after LPS treatment in wild types (n = 42, SD 5), but no increase was seen in TRPV4 −/− mice (n = 42, SD 2). After desensitization of primary afferent C-nerve fibers with RTX, c-fos expression in TRPV4−/− mice decreased significantly (threefold) (n = 12, SD 4). Results imply that TRPV4 channels are important for bladder afferent signaling. TRPV4 −/− mice bladders generate more noxious sensory output, which is predominantly mediated through TRPV1 expressing high threshold nerve fibers. This study reveals TRPV1 related adaptive changes in afferent pathways of the TRPV4 −/− mouse. We propose that this effect is caused by a congenital impairment of low threshold nerves that mediate normal bladder filling sensations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00424-016-1859-9) contains supplementary material, which is available to authorized users.