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Aims: Activation of transient receptor potential vanilloid 1 (TRPV1) ion channels inhibits inflammation, enhance cytotoxic immune response, and may have therapeutic potential in treatment of cancer characterized by increased systemic inflammation. We here determined how activation of TRPV1 alters immune response of tumor-bearing mice., Main Methods: Three different metastatic subset of 4 T1 breast carcinoma cells were used to induce tumors in Balb-c mice. Mix leukocyte cultures (MLCs) using spleens and draining lymph nodes were prepared and stimulated with various challenges. Effects TRPV1 agonists including capsaicin, antagonist (AMG9810) and Gambogic Amide (GA), a TrkA agonist that sensitizes TRPV1, on secreted levels of cytokines were determined., Key Findings: MLCs of tumor-bearing mice secreted markedly higher levels of IL-6 and lower levels of IFN-γ compared to control mice. We observed differential effects of TRPV1 agonists in control and mice bearing different subset of metastatic cells. TRPV1 increased IFN-γ and IL-17 secretion in control mice while they markedly increased IL-6 secretion and suppressed IFN--γ secretion in tumor-bearing mice. Unexpectedly, AMG9810 acted as an inverse agonist and did not antagonize the effects of TRPV1 agonists., Significance: Our results demonstrate constitutive activity of TRPV1 in immune cells, suggesting cross activation. To prevent excessive chronic activation of TRPV1 in immune cells in the presence of metastatic breast carcinoma, lower doses of TRPV1 agonist should be considered. Unexpected findings further document that a drug can have multiple intrinsic activities depending on surrounding factors can act on the same receptor as an agonist, antagonist or inverse agonist., (Copyright © 2021. Published by Elsevier Inc.)

Dry skin is a symptom of skin barrier dysfunction that evokes pruritus; however, the cutaneous neuroimmune interactions underlying dry skin-induced pruritus remain unclear. Therefore, we aimed to elucidate the mechanisms underlying dry skin-induced pruritus. To this end, an acetone/ethanol/water (AEW)-induced mouse model of dry skin was used in this study. We observed that the production of thymic stromal lymphopoietin (TSLP) significantly increased in the keratinocytes of AEW mice. Importantly, treatment with an antagonist of transient receptor potential cation channel subfamily V member 4 (TRPV4), HC067047, ameliorated dry skin conditions in AEW mice. The symptoms of dry skin were significantly reduced in Trpv4 knockout (KO) mice following treatment with AEW. The increase in the intracellular calcium levels by TSLP in the dorsal root ganglia (DRG) of Trpv4 KO mice was also significantly attenuated. The spontaneous scratching bouts were significantly decreased in both the HC067047-treated and Trpv4 KO AEW mice. Importantly, the TSLP-dependent release of tryptase from the mast cells was significantly reduced in both the HC067047-treated mice and Trpv4 KO AEW mice. Notably, inhibition of the TSLP-induced signaling pathway in DRG selectively reduced the spontaneous scratching bouts in AEW mice. Overall, the results demonstrated that the cutaneous neuroimmune interactions of TSLP and TRPV4 play pivotal roles in dry skin-induced pruritus., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Lee and Shim.)

The importance of innate immune cells to sense and respond to their physical environment is becoming increasingly recognized. Innate immune cells (e.g. macrophages and neutrophils) are able to receive mechanical signals through several mechanisms. In this review, we discuss the role of mechanosensitive ion channels, such as Piezo1 and transient receptor potential vanilloid 4 (TRPV4), and cell adhesion molecules, such as integrins, selectins, and cadherins in biology and human disease. Furthermore, we explain that these mechanical stimuli activate intracellular signaling pathways, such as MAPK (p38, JNK), YAP/TAZ, EDN1, NF-kB, and HIF-1α, to induce protein conformation changes and modulate gene expression to drive cellular function. Understanding the mechanisms by which immune cells interpret mechanosensitive information presents potential targets to treat human disease. Important areas of future study in this area include autoimmune, allergic, infectious, and malignant conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Orsini, Perelas, Southern, Grove, Olman and Scheraga.)

The endocannabinoid system is a promising target to mitigate pain as the endocannabinoids are endogenous ligands of the pain-mediating receptors-cannabinoid receptors 1 and 2 (CB1 and CB2) and TRPV1. Herein, we report on a class of lipids formed by the epoxidation of N-arachidonoyl-dopamine (NADA) and N-arachidonoyl-serotonin (NA5HT) by epoxygenases. EpoNADA and epoNA5HT are dual-functional rheostat modulators of the endocannabinoid-TRPV1 axis. EpoNADA and epoNA5HT are stronger modulators of TRPV1 than either NADA or NA5HT, and epoNA5HT displays a significantly stronger inhibition on TRPV1-mediated responses in primary afferent neurons. Moreover, epoNA5HT is a full CB1 agonist. These epoxides reduce the pro-inflammatory biomarkers IL-6, IL-1β, TNF-α and nitrous oxide and raise anti-inflammatory IL-10 cytokine in activated microglial cells. The epoxides are spontaneously generated by activated microglia cells and their formation is potentiated in the presence of anandamide. Detailed kinetics and molecular dynamics simulation studies provide evidence for this potentiation using the epoxygenase human CYP2J2. Taken together, inflammation leads to an increase in the metabolism of NADA, NA5HT and other eCBs by epoxygenases to form the corresponding epoxides. The epoxide metabolites are bioactive lipids that are potent, multi-faceted molecules, capable of influencing the activity of CB1, CB2 and TRPV1 receptors.

In this article, we propose that differences in COVID-19 morbidity may be associated with transient receptor potential ankyrin 1 (TRPA1) and/or transient receptor potential vanilloid 1 (TRPV1) activation as well as desensitization. TRPA1 and TRPV1 induce inflammation and play a key role in the physiology of almost all organs. They may augment sensory or vagal nerve discharges to evoke pain and several symptoms of COVID-19, including cough, nasal obstruction, vomiting, diarrhea, and, at least partly, sudden and severe loss of smell and taste. TRPA1 can be activated by reactive oxygen species and may therefore be up-regulated in COVID-19. TRPA1 and TRPV1 channels can be activated by pungent compounds including many nuclear factor (erythroid-derived 2) (Nrf2)-interacting foods leading to channel desensitization. Interactions between Nrf2-associated nutrients and TRPA1/TRPV1 may be partly responsible for the severity of some of the COVID-19 symptoms. The regulation by Nrf2 of TRPA1/TRPV1 is still unclear, but suggested from very limited clinical evidence. In COVID-19, it is proposed that rapid desensitization of TRAP1/TRPV1 by some ingredients in foods could reduce symptom severity and provide new therapeutic strategies., (© 2021 S. Karger AG, Basel.)

The orchestration of host immune responses to enteric bacterial pathogens is a complex process involving the integration of numerous signals, including from the nervous system. Despite the recent progress in understanding the contribution of neuroimmune interactions in the regulation of inflammation, the mechanisms and effects of this communication during enteric bacterial infection are only beginning to be characterized. As part of this neuroimmune communication, neurons specialized to detect painful or otherwise noxious stimuli can respond to bacterial pathogens. Highlighting the complexity of these systems, the immunological consequences of sensory neuron activation can be either host adaptive or maladaptive, depending on the pathogen and organ system. These are but one of many types of neuroimmune circuits, with the vagus nerve and sympathetic innervation of numerous organs now known to modulate immune cell function and therefore dictate immunological outcomes during health and disease. Here, we review the evidence for neuroimmune communication in response to bacterial pathogens, and then discuss the consequences to host morbidity and mortality during infection of the gastrointestinal tract., (Copyright © 2020 American Society for Microbiology.)

The airway epithelium plays a critical role in innate responses to airborne allergens by secreting IL-1 family cytokines such as IL-1α and IL-33 as alarmins that subsequently orchestrate appropriate immune responses. Previous studies revealed that epithelial IL-33 secretion by allergens such as Alternaria alternata or house dust mite involves Ca 2+ -dependent signaling, via initial activation of ATP-stimulated P2YR2 (type 2 purinoceptor) and subsequent activation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase DUOX1. We sought to identify proximal mechanisms by which epithelial cells sense these allergens and here highlight the importance of PAR2 (protease-activated receptor 2) and TRP (transient receptor potential) Ca 2+ channels such as TRPV1 (TRP vanilloid 1) in these responses. Combined studies of primary human nasal and mouse tracheal epithelial cells, as well as immortalized human bronchial epithelial cells, indicated the importance of both PAR2 and TRPV1 in IL-33 secretion by both Alternaria alternata and house dust mite, based on both pharmacological and genetic approaches. TRPV1 was also critically involved in allergen-induced ATP release, activation of DUOX1, and redox-dependent activation of EGFR (epidermal growth factor receptor). Moreover, genetic deletion of TRPV1 dramatically attenuated allergen-induced IL-33 secretion and subsequent type 2 responses in mice in vivo . TRPV1 not only contributed to ATP release and P2YR2 signaling but also was critical in downstream innate responses to ATP, indicating potentiating effects of P2YR2 on TRPV1 activation. In aggregate, our studies illustrate a complex relationship between various receptor types, including PAR2 and P2YR2, in epithelial responses to asthma-relevant airborne allergens and highlight the central importance of TRPV1 in such responses.

As obligate parasites, viruses highjack, modify and repurpose the cellular machinery for their own replication. Viral proteins have, therefore, evolved biological functions, such as signalling potential, that alter host cell physiology in ways that are still incompletely understood. Retroviral envelope glycoproteins interact with several host proteins, extracellularly with their cellular receptor and anti-envelope antibodies, and intracellularly with proteins of the cytoskeleton or sorting, endocytosis and recirculation pathways. Here, we examined the impact of endogenous retroviral envelope glycoprotein expression and interaction with host proteins, particularly antibodies, on the cell, independently of retroviral infection. We found that in the commonly used C57BL/6 substrains of mice, where murine leukaemia virus (MLV) envelope glycoproteins are expressed by several endogenous MLV proviruses, the highest expressed MLV envelope glycoprotein is under the control of an immune-responsive cellular promoter, thus linking MLV envelope glycoprotein expression with immune activation. We further showed that antibody ligation induces extensive internalisation from the plasma membrane into endocytic compartments of MLV envelope glycoproteins, which are not normally subject to constitutive endocytosis. Importantly, antibody binding and internalisation of MLV envelope glycoproteins initiates signalling cascades in envelope-expressing murine lymphocytic cell lines, leading to cellular activation. Similar effects were observed by MLV envelope glycoprotein ligation by its cellular receptor mCAT-1, and by overexpression in human lymphocytic cells, where it required an intact tyrosine-based YXXΦ motif in the envelope glycoprotein cytoplasmic tail. Together, these results suggest that signalling potential is a general property of retroviral envelope glycoproteins and, therefore, a target for intervention., Competing Interests: The authors have declared that no competing interests exist.

Chronic obstructive pulmonary disease (COPD) is a chronic, progressive lung disease with few successful treatments, and is strongly associated with cigarette smoking (CS). Since the novel coronavirus has spread worldwide seriously, there is growing concern that patients who have chronic respiratory conditions like COPD can easily be infected and are more prone to having severe illness and even mortality because of lung dysfunction. Loquat leaves have long been used as an important material for both pharmaceutical and functional applications in the treatment of lung disease in Asia, especially in China and Japan. Total flavonoids (TF), the main active components derived from loquat leaves, showed remarkable anti-inflammatory and antioxidant activities. However, their protective activity against CS-induced COPD airway inflammation and oxidative stress and its underlying mechanism still remain not well-understood. The present study uses a CS-induced mouse model to estimate the morphological changes in lung tissue. The results demonstrated that TF suppressed the histological changes in the lungs of CS-challenged mice, as evidenced by reduced generation of pro-inflammatory cytokines including interleukin 6 (IL-6), IL-1β, tumor necrosis factor α (TNF-α), nitric oxide (NO), and inducible nitric oxide synthase (iNOS) and diminished the protein expression of transient receptor potential vanilloid 1 (TRPV1). Moreover, TF also inhibited phosphorylation of IKK, IκB and NFκB and increased p-Akt. Interestingly, TF could inhibit CS-induced oxidative stress in the lungs of COPD mice. TF treatment significantly inhibited the level of malondialdehyde (MDA) and increased the activity of superoxide dismutase (SOD). In addition, TF markedly downregulated TRPV1 and cytochrome P450 2E1 (CYP2E1) and upregulated the expression of SOD-2, while the p-JNK level was observed to be inhibited in COPD mice. Taken together, our findings showed that the protective effect and putative mechanism of the action of TF resulted in the inhibition of inflammation and oxidative stress through the regulation of TRPV1 and the related signal pathway in lung tissues. It suggested that TF derived from loquat leaves could be considered to be an alternative or a new functional material and used for the treatment of CS-induced COPD.

Mechanical cell-matrix interactions can drive the innate immune responses to infection; however, the molecular underpinnings of these responses remain elusive. This study was undertaken to understand the molecular mechanism by which the mechanosensitive cation channel, transient receptor potential vanilloid 4 (TRPV4), alters the in vivo response to lung infection. For the first time, to our knowledge, we show that TRPV4 protects the lung from injury upon intratracheal Pseudomonas aeruginosa in mice. TRPV4 functions to enhance macrophage bacterial clearance and downregulate proinflammatory cytokine secretion. TRPV4 mediates these effects through a novel mechanism of molecular switching of LPS signaling from predominant activation of the MAPK, JNK, to that of p38. This is accomplished through the activation of the master regulator of inflammation, dual-specificity phosphatase 1. Further, TRPV4's modulation of the LPS signal is mechanosensitive in that both upstream activation of p38 and its downstream biological consequences depend on pathophysiological range extracellular matrix stiffness. We further show the importance of TRPV4 on LPS-induced activation of macrophages from healthy human controls. These data are the first, to our knowledge, to demonstrate new roles for macrophage TRPV4 in regulating innate immunity in a mechanosensitive manner through the modulation of dual-specificity phosphatase 1 expression to mediate MAPK activation switching., (Copyright © 2020 by The American Association of Immunologists, Inc.)

Calcium entry is central to the functional processes in mast cells and basophils that contribute to the induction and maintenance of inflammatory responses. Mast cells and basophils express an array of calcium channels, which mediate responses to diverse stimuli triggered by small bioactive molecules, physicochemical stimuli and immunological inputs including antigens and direct immune cell interactions. These cells are also highly responsive to certain venoms (such as Hymenoptera envenomations), which cause histamine secretion, cytokine release and an array of pro-inflammatory functional responses. There are gaps in our understanding of the coupling of venom exposure to specific signaling pathways such as activation of calcium channels. In the present study, we performed a current survey of a model mast cell line selected for its pleiotropic responsiveness to multiple pro-inflammatory inputs. As a heterogenous stimulus, Hymenoptera venom activates multiple classes of conductance at the population level but tend to lead to the measurement of only one type of conductance per cell, despite the cell co-expressing multiple channel types. The data show that I CRAC , I ARC, and TRPV-like currents are present in the model mast cell populations and respond to venom exposure. We further assessed individual venom components, specifically secretagogues and arachidonic acid, and identified the conductances associated with these stimuli in mast cells. Single-cell calcium assays and immunofluorescence analysis show that there is heterogeneity of channel expression across the cell population, but this heterogeneity does not explain the apparent selectivity for specific channels in response to exposure to venom as a composite stimulus.

Trichomoniasis is a common sexually transmitted infection caused by Trichomonas vaginalis, which actually does not exist a vaccine for control or prevention. Thus, the identification of new and potent immunogens in T. vaginalis, which can contribute to the development of a vaccine against this parasite, is necessary. Therefore, the aim of this work was to evaluate the potential of a recombinant Transient Receptor Potential-like channel of T. vaginalis (TvTRPV), as a promising immunogen in BALB/c mice. First, TvTRPV was cloned and expressed as a recombinant protein in Escherichia coli BL21 cells and purified by nickel affinity. Next, BALB/c mice were immunized and the antibody levels in mice serum and cytokines from the supernatant of macrophages and from co-culture systems were evaluated. Recombinant TvTRPV triggered high levels of specific total IgG in sera from the immunized mice. Also, a statistically significant increase of cytokines: IL-1β, IL-6, and TNF-α after stimulation with the corresponding antigens in vitro, was identified. Moreover, co-cultures using CD4+ T cells from immunized mice were able to identify higher levels of IL-10 and IFN-γ. These results were useful to validate the immunogenicity of TvTRPV in BALB/c mice, where IL-10-IFN-γ-secreting cells could play a role in infection control, supporting the potential of TvTRPV as a promising target for vaccine against T. vaginalis.

Studying TRP channel expressing nociceptors requires the identification of the respective subpopulations as well as the quantification of dynamic cellular events. However, the heterogeneity of sensory neurons and associated nonneuronal cells demands the analysis of large numbers of cells to reflect the distribution of entire populations. Here we report a detailed workflow how to apply high-content screening (HCS) microscopy to signaling events in TRPV1-positive neurons as well as an approach to use the selective elimination of TRPV1 positive cells from dissociated rat sensory ganglia as base for transcriptomic analysis of TRPV1-positive cells and/or as control for TRPV1 antibody specificity.

A sensitive and highly efficient approach to monitor the expression of proteins on live cells was urgently needed to demonstrate its factor and mechanism and most important for clinical diagnostics and molecular biology. Herein, we developed a simple and highly efficient strategy, nonlinear hybridization chain reaction (nonlinear HCR), for the sensitive determination of proteins on live cells with transient receptor potential vanilloid 4 (TRPV4) and RAW264.7 cells as a model. Unlike the normal hybridization chain reaction (HCR) with multiplicative amplification, an exponential amplified fluorescent response could be obtained in theory based on the proposed nonlinear HCR. As a result, the nonlinear HCR generated a significant enhancement about 3 times compared with the normal HCR and 10 times compared with the directly immunofluorescence assay. Based on the proposed nonlinear HCR, the fluorescent signals increased with the concentration of TRPV4 in the range from 10 pg/mL to 100 ng/mL with a detection limit of 2.8 pg/mL, which would be useful for the sensitive detection of proteins in cell lysis or on cell surface. At the same time, the significant improvements via nonlinear HCR were achieved in the fluorescent imaging system compared with traditional immunofluorescence staining and normal HCR, proving the significant value of nonlinear HCR-based amplification strategy. Success in the establishment of the highly efficient nonlinear HCR strategy offered a simple and sensitive approach to demonstrate the concentration of special proteins on cell and other proteins and nucleotide potentially, revealing a simple and efficient technology for research fields of clinical diagnostics and molecular biology., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Immunological interdependence between the two eyes has been reported for the cornea and the retina but not for the ocular mucosal surface. Intriguingly, patients frequently report ocular surface-related symptoms in the other eye after unilateral ocular surgery. Here we show how unilateral eye injuries in mice affect the mucosal immune response of the opposite ocular surface. We report that, despite the lack of lymphatic cross-drainage, a neurogenic inflammatory reflex in the contralateral conjunctiva is sufficient to increase, first, epithelial nuclear factor kappa B signaling, then, dendritic cell maturation, and finally, expansion of effector, instead of regulatory, T cells in the draining lymph node, leading to disrupted ocular mucosal tolerance. We also show that damage to ocular surface nerves is required. Using pharmacological inhibitors and agonists, we identified transient receptor potential vanilloid 1 (TRPV1) channel as the receptor sensing tissue damage in the injured eye and substance P released in the opposite ocular surface as the effector of the sympathetic response. Finally, blocking either step prevented subsequent ocular allergic reactions in the opposite eye in a unilateral corneal alkali burn model. This study demonstrates that both ocular surfaces are immunologically linked and suggests potential therapeutic targets for intervention.

This study revealed the modulatory role of transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) cation channels in the Aldara-induced (5% imiquimod) murine psoriasis model using selective antagonists and genetically altered animals. We have also developed a refined localized model to enable internal controls and reduce systemic effects. Skin pathology was quantified by measuring skin thickness, scaling, blood flow, and analyzing dermal cellular infiltrate, whereas nocifensive behaviors were also observed. Cytokine gene expression profiles were measured ex vivo. Psoriasiform dermatitis was significantly enhanced in TRPA1 knockout mice and with TRPA1 antagonist (A967079) treatment. By comparison, symptoms were decreased when TRPV1 function was inhibited. Imiquimod induced Ca 2+ influx in TRPA1-, but not in TRPV1-expressing cell lines. Immunohistochemical studies revealed that CD4+ T helper cells express TRPA1 but not TRPV1 ion channels in mice skin. Compared with the TRPV1 knockout animals, additional elimination of the TRPA1 channels in the TRPV1/TRPA1 double knockout mice did not modify the outcome of the imiquimod-induced reaction, further supporting the dominant role of TRPV1 in the process. Our results suggest that the protective effects in psoriasiform dermatitis can be mediated by the activation of neuronal and nonneuronal TRPA1 receptors., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

PAR2 activation in basal keratinocytes stimulates inflammation via the Ca 2+ -dependent production of mediators such as IL-1β, TNF-α, and TSLP. In this study, we investigated PAR2 calcium signaling and the consequent production of inflammatory mediators in differentiated human primary keratinocytes (DhPKs). Stimulation with the PAR2-activating peptide SLIGKV promoted Ca 2+ store depletion in both undifferentiated human primary keratinocytes and DhPKs. SLIGKV-evoked Ca 2+ store depletion did not trigger the store-operated Ca 2+ entry (i.e., SOCE) through ORAI1 in DhPKs compared with undifferentiated human primary keratinocytes. The inhibition of phospholipase C and the concomitant inhibition of TRPV1 and inositol triphosphate receptor in DhPKs abrogated the SLIGKV-evoked Ca 2+ store depletion; NF-κB activity; and the production of inflammatory mediators such as IL-1β, TNF-α, and TSLP. Taken together, these results indicate a key role for both InsP3R and TRPV1 in Ca 2+ internal stores in the PAR2-evoked Ca 2+ release and consequent skin inflammation in DhPKs. These findings may provide clues to understanding the pathological role of DhPKs in skin disorders in which PAR2 is known to be involved, such as atopic dermatitis, Netherton syndrome, and psoriasis., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Transient receptor potential (TRP) ion channels were first characterized on neurons, where they are classically implicated in sensory functions; however, research in recent decades has shown that many of these channels are also expressed on nonneuronal cell types. Emerging findings have highlighted the role of TRP channels in the skin, where they have been shown to be important in numerous cutaneous functions. Of particular interest is TRPV3, which was first described on keratinocytes. Its functional importance was supported when its gain-of-function mutation was linked to Olmsted syndrome, which is characterized by palmoplantar keratoderma, periorifacial hyperkeratosis, diffuse hypotrichosis and alopecia, and itch. Despite these exciting results, we have no information about the role and functionality of TRPV3 on keratinocytes at the cellular level. In this study, we identified TRPV3 expression both on human skin and cultured epidermal keratinocytes. TRPV3 stimulation was found to function as a Ca 2+ -permeable ion channel that suppresses proliferation of epidermal keratinocytes and induces cell death. Stimulation of the channel also triggers a strong proinflammatory response via the NF-κB pathway. Collectively, our data show that TRPV3 is functionally expressed on human epidermal keratinocytes and that it plays a role in cutaneous inflammatory processes., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Chronic itch is a highly debilitating symptom that underlies many medical disorders with no universally effective treatments. Although unique neuronal signaling cascades in the sensory ganglia and spinal cord have been shown to critically promote the pathogenesis of chronic itch, the role of skin-associated cells remains poorly understood., Objective: We sought to examine the cutaneous mechanisms underlying transient receptor potential vanilloid 4 (TRPV4)-mediated allergic and nonallergic chronic itch., Methods: Expression of TRPV4 in chronic itch and healthy control skin preparations was examined by using real-time RT-PCR. Trpv4 eGFP mice were used to study the expression and function of TRPV4 in the skin by means of immunofluorescence staining, flow cytometry, calcium imaging, and patch-clamp recordings. Genetic and pharmacologic approaches were used to examine the role and underlying mechanisms of TRPV4 in mouse models of dry skin-associated chronic itch and spontaneous scratching associated with squaric acid dibutylester-induced allergic contact dermatitis., Results: TRPV4 is selectively expressed by dermal macrophages and epidermal keratinocytes in mice. Lineage-specific deletion of TRPV4 in macrophages and keratinocytes reduces allergic and nonallergic chronic itch in mice, respectively. Importantly, TRPV4 expression is significantly increased in skin biopsy specimens from patients with chronic idiopathic pruritus in comparison with skin from healthy control subjects. Moreover, TRPV4-dependent chronic itch requires 5-hydroxytryptamine (5-HT) signaling secondary to activation of distinct 5-HT receptors in mice with allergic and those with nonallergic chronic itch conditions., Conclusion: Our study reveals previously unrecognized mechanisms by which TRPV4-expressing epithelial and immune cells in the skin critically and dynamically mediate chronic itch and unravels novel targets for therapeutics in the setting of chronic itch., (Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Atherosclerosis is characterized by the accumulation of lipids within the arterial wall. Although activation of TRPV1 cation channels by capsaicin may reduce lipid storage and the formation of atherosclerotic lesions, a clinical use for capsaicin has been limited by its chronic toxicity. Here we show that coupling of copper sulfide (CuS) nanoparticles to antibodies targeting TRPV1 act as a photothermal switch for TRPV1 signaling in vascular smooth muscle cells (VSMCs) using near-infrared light. Upon irradiation, local increases of temperature open thermo-sensitive TRPV1 channels and cause Ca 2+ influx. The increase in intracellular Ca 2+ activates autophagy and impedes foam cell formation in VSMCs treated with oxidized low-density lipoprotein. In vivo, CuS-TRPV1 allows photoacoustic imaging of the cardiac vasculature and reduces lipid storage and plaque formation in ApoE - / - mice fed a high-fat diet, with no obvious long-term toxicity. Together, this suggests CuS-TRPV1 may represent a therapeutic tool to locally and temporally attenuate atherosclerosis.

Although both persistent itch and inflammation are commonly associated with allergic contact dermatitis (ACD), it is not known if they are mediated by shared or distinct signaling pathways. Here we show that both TRPA1 and TRPV1 channels are required for generating spontaneous scratching in a mouse model of ACD induced by squaric acid dibutylester (SADBE), a small molecule hapten, through directly promoting the excitability of pruriceptors. TRPV1 but not TRPA1 channels protect the skin inflammation, as genetic ablation of TRPV1 function or pharmacological ablation of TRPV1-positive sensory nerves promotes cutaneous inflammation in the SADBE-induced ACD. Our results demonstrate that persistent itch and inflammation are mediated by distinct cellular and molecular mechanisms in a mouse model of ACD. Identification of distinct roles of TRPA1 and TRPV1 in regulating itch and inflammation may provide new insights into the pathophysiology and treatment of chronic itch and inflammation in ACD patients.

Transient receptor potential vanilloid type 1 channel (TRPV1), as a ligand-gated non-selective cation channel, has recently been demonstrated to have wide expression in the neuro-immune axis, where its multiple functions occur through regulation of both neuronal and non-neuronal activities. Growing evidence has suggested that TRPV1 is functionally expressed in glial cells, especially in the microglia and astrocytes. Glial cells perform immunological functions in response to pathophysiological challenges through pro-inflammatory or anti-inflammatory cytokines and chemokines in which TRPV1 is involved. Sustaining inflammation might mediate a positive feedback loop of neuroinflammation and exacerbate neurological disorders. Accumulating evidence has suggested that TRPV1 is closely related to immune responses and might be recognized as a molecular switch in the neuroinflammation of a majority of seizures and neurodegenerative diseases. In this review, we evidenced that inflammation modulates the expression and activity of TRPV1 in the central nervous system (CNS) and TRPV1 exerts reciprocal actions over neuroinflammatory processes. Together, the literature supports the hypothesis that TRPV1 may represent potential therapeutic targets in the neuro-immune axis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Candida albicans can enter skeletal tissue through a skin wound in an immunocompromised host or by contamination during orthopedic surgery. Such Candida osteomyelitis is accompanied by severe pain and bone destruction. It is established that nociceptor innervation occurs in skin and bone, but the mechanisms of nociceptive modulation in fungal inflammation remain unclear. In this study, we show that C. albicans stimulates Nav1.8-positive nociceptors via the β-glucan receptor Dectin-1 to induce calcitonin gene-related peptide (CGRP). This induction of CGRP is independent of Bcl-10 or Malt-1 but dependent on transient receptor potential cation channel subfamily V member 1 (TRPV1)/transient receptor potential cation channel subfamily A member 1 (TRPA1) ion channels. Hindpaw β-glucan injection after Nav1.8-positive nociceptor ablation or in TRPV1/TRPA1 deficiency showed dramatically increased osteoinflammation accompanied by impaired CGRP production. Strikingly, CGRP suppressed β-glucan-induced inflammation and osteoclast multinucleation via direct suppression of nuclear factor-κB (NF-κB) p65 by the transcriptional repressor Jdp2 and inhibition of actin polymerization, respectively. These findings clearly suggest a role for Dectin-1-mediated sensocrine pathways in the resolution of fungal osteoinflammation., (Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.)

Flow cytometric analysis of calcium mobilisation has been in use for many years in the study of specific receptor engagement or isolated cell:cell communication. However, calcium mobilisation/signaling is key to many cell functions including apoptosis, mobility and immune responses. Here we combine multiplex surface staining of whole spleen with Indo-1 AM to visualise calcium mobilisation and examine calcium signaling in a mixed immune cell culture over time. We demonstrate responses to a TRPV1 agonist in distinct cell subtypes without the need for cell separation. Multi parameter staining alongside Indo-1 AM to demonstrate calcium mobilization allows the study of real time calcium signaling in a complex environment., (Copyright © 2017. Published by Elsevier Inc.)

Sepsis is a systemic inflammatory response syndrome triggered by lipopolysaccharide (LPS), an outer membrane component of gram-negative bacteria, and cytokine production via LPS-induced macrophage activation is deeply involved in its pathogenesis. Effective therapy of sepsis has not yet been established. However, it was reported that transient receptor potential vanilloid 1 (TRPV1) channel antagonist capsazepine (CPZ; a capsaicin analogue) attenuates sepsis in a murine model [Ang et al., PLoS ONE 6(9) (2011) e24535; J. Immunol. 187 (2011) 4778-4787]. Here, we profiled the effects of four TRPV1 channel antagonists, AMG9810, SB366791, BCTC and CPZ, on the release of IL-6, IL-1β and IL-18, and on expression of cyclooxygenase 2 (COX-2) in LPS-activated macrophages. Treatment of murine macrophage J774.1 cells or BALB/c mouse-derived intraperitoneal immune cells with LPS induced pro-inflammatory cytokines production and COX-2 expression. Pretreatment with AMG9810 or CPZ significantly suppressed the release of IL-6, IL-1β and IL-18, and COX-2 expression, whereas SB366791 and BCTC were less effective. These results support a role of TRPV1 channel in macrophage activation, but also indicate that only a subset of TRPV1 channel antagonists may be effective in suppressing inflammatory responses. These results suggest that at least some TRPV1 channel antagonists, such as AMG9810 and CPZ, may be candidate anti-inflammatory agents for treatment of sepsis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Interleukin-6 (IL-6) is released from skeletal muscle cells and induced by exercise, heat, catecholamine, glucose, lipopolysaccharide, reactive oxygen species, and inflammation. However, the mechanism that induces release of IL-6 from skeletal muscle cells remains unknown. Thermosensitive transient receptor potential (TRP) proteins such as TRPV1-4 play vital roles in cellular functions. In this study we hypothesized that TRPV1 senses heat, transmits a signal into the nucleus, and produces IL-6. The purpose of the present study is to investigate the underlying mechanisms whereby skeletal muscle cells sense and respond to heat. When mouse myoblast cells were exposed to 37-42°C for 2 h, mRNA expression of IL-6 increased in a temperature-dependent manner. Heat also increased IL-6 secretion in myoblast cells. A fura 2 fluorescence dual-wavelength excitation method showed that heat increased intracellular calcium flux in a temperature-dependent manner. Intracellular calcium flux and IL-6 mRNA expression were increased by the TRPV1 agonists capsaicin and N -arachidonoyldopamine and decreased by the TRPV1 antagonists AMG9810 and SB366791 and siRNA-mediated knockdown of TRPV1. TRPV2, 3, and 4 agonists did not change intracellular calcium flux. Western blotting with inhibitors demonstrated that heat increased phosphorylation levels of TRPV1, followed by PKC and cAMP response element-binding protein (CREB). PKC inhibitors, Gö6983 and staurosporine, CREB inhibitors, curcumin and naphthol AS-E, and knockdown of CREB suppressed the heat-induced increases in IL-6. These results indicate that heat increases IL-6 in skeletal muscle cells through the TRPV1, PKC, and CREB signal transduction pathway. NEW & NOTEWORTHY Heat increases the release of interleukin-6 (IL-6) from skeletal muscle cells. IL-6 has been shown to serve immune responses and metabolic functions in muscle. It can be anti-inflammatory as well as proinflammatory. However, the mechanism that induces release of IL-6 from skeletal muscle cells remains unknown. Here we show that heat increases IL-6 in skeletal muscle cells through the transient receptor potential vannilloid 1, PKC, and cAMP response element-binding protein signal transduction pathway., (Copyright © 2017 the American Physiological Society.)

Sequestration of nerve growth factor has been used successfully in the management of pain in animal models of bone disease and in human osteoarthritis. However, the mechanisms of nerve growth factor-induced bone pain and its role in modulating inflammatory bone pain remain to be determined. In this study, we show that nerve growth factor receptors (TrkA and p75) and some other nerve growth factor-signaling molecules (TRPV1 and Nav1.8, but not Nav1.9) are expressed in substantial proportions of rat bone nociceptors. We demonstrate that nerve growth factor injected directly into rat tibia rapidly activates and sensitizes bone nociceptors and produces acute behavioral responses with a similar time course. The nerve growth factor-induced changes in the activity and sensitivity of bone nociceptors we report are dependent on signaling through the TrkA receptor, but are not affected by mast cell stabilization. We failed to show evidence for longer term changes in expression of TrkA, TRPV1, Nav1.8 or Nav1.9 in the soma of bone nociceptors in a rat model of inflammatory bone pain. Thus, retrograde transport of NGF/TrkA and increased expression of some of the common nerve growth factor signaling molecules do not appear to be important for the maintenance of inflammatory bone pain. The findings are relevant to understand the basis of nerve growth factor sequestration and other therapies directed at nerve growth factor signaling, in managing pain in bone disease.

Autoimmune diseases refer to a spectrum of diseases characterized by an active immune response against the host, which frequently involves increased autoantibody production. The pathogenesis of autoimmune diseases is multifactorial and the exploitation of novel effective treatment is urgent. Capsaicin is a nutritional factor, the active component of chili peppers, which is responsible for the pungent component of chili pepper. As a stimuli, capsaicin selectively activate transient receptor potential vanilloid subfamily 1(TRPV1) and exert various biological effects. This review discusses the effect of capsaicin through its receptor on the development and modulation of autoimmune diseases, which may shed light upon potential therapies in capsaicin-targeted approaches., (Copyright © 2016. Published by Elsevier B.V.)

Neuro-immune interactions, particularly those driven by neuropeptides, are increasingly implicated in immune responses. For instance, triggering calcium-channel transient receptor potential vanilloid 1 (TRPV1) on sensory nerves induces the release of calcitonin-gene-related peptide (CGRP), a neuropeptide known to moderate dendritic cell activation and T helper cell type 1 polarization. Despite observations that CGRP is not confined to the nervous system, few studies have addressed the possibility that immune cells can respond to well-documented 'neural' ligands independently of peripheral nerves. Here we have identified functionally relevant TRPV1 on primary antigen-presenting cells of the spleen and have demonstrated both calcium influx and CGRP release in three separate strains of mice using natural agonists. Furthermore, we have shown down-regulation of activation markers CD80/86 on dendritic cells, and up-regulation of interleukin-6 and interleukin-10 in response to CGRP treatment. We suggest that dendritic cell responses to neural ligands can amplify neuropeptide release, but more importantly that variability in CGRP release across individuals may have important implications for immune cell homeostasis., (© 2015 John Wiley & Sons Ltd.)

As an organism is exposed to pathogens during very early development, specific defense mechanisms must take effect. In this study, we used a germ-free zebrafish embryo model to show that osmotic stress regulates the activation of immunity and host protection in newly hatched embryos. Mechanistically, skin keratinocytes were responsible for both sensing the hyposmolarity of the aquatic environment and mediating immune effector mechanisms. This occurred through a transient potential receptor vanilloid 4/Ca(2+)/TGF-β-activated kinase 1/NF-κB signaling pathway. Surprisingly, the genes encoding antimicrobial effectors, which do not have the potential to cause tissue damage, are constitutively expressed during development, independently of both commensal microbes and osmotic stress. Our results reveal that osmotic stress is associated with the induction of developmental immunity in the absence of tissue damage and point out to the embryo skin as the first organ with full capacities to mount an innate immune response., (Copyright © 2016 by The American Association of Immunologists, Inc.)

Transient receptor potential vanilloid 1 (TRPV1), which has been identified as a molecular target for the activation of sensory neurons by various painful stimuli, was reported to regulate the signaling and activation of CD4+ T cells. However, the role of TRPV1 in CD4+ T cell in allergic rhinitis remains poorly understood. In this study, TRPV1 expression was localized in CD4+ T cells. Both knockout and chemical inhibition of TRPV1 suppressed Th2/Th17 cytokine production in CD4 T cells and Jurkat T cells, respectively, and can suppress T cell receptor signaling pathways including NF-κB, MAP kinase, and NFAT. In TRPV1 knockout allergic rhinitis (AR) mice, eosinophil infiltration, Th2/Th17 cytokines in the nasal mucosa, and total and ova-specific IgE levels in serum decreased, compared with wild-type AR mice. The TRPV1 antagonists, BCTC or theobromine, showed similar inhibitory immunologic effects on AR mice models. In addition, the number of TRPV1+/CD4+ inflammatory cells increased in the nasal mucosa of patients with AR, compared with that of control subjects. Thus, TRPV1 activation on CD4+ T cells is involved in T cell receptor signaling, and it could be a novel therapeutic target in AR.

Macrophage phagocytosis of particles and pathogens is an essential aspect of innate host defense. Phagocytic function requires cytoskeletal rearrangements that depend on the interaction between macrophage surface receptors, particulates/pathogens, and the extracellular matrix. In the present study we determine the role of a mechanosensitive ion channel, transient receptor potential vanilloid 4 (TRPV4), in integrating the LPS and matrix stiffness signals to control macrophage phenotypic change for host defense and resolution from lung injury. We demonstrate that active TRPV4 mediates LPS-stimulated murine macrophage phagocytosis of nonopsonized particles (Escherichia coli) in vitro and opsonized particles (IgG-coated latex beads) in vitro and in vivo in intact mice. Intriguingly, matrix stiffness in the range seen in inflamed or fibrotic lung is required to sensitize the TRPV4 channel to mediate the LPS-induced increment in macrophage phagocytosis. Furthermore, TRPV4 is required for the LPS induction of anti-inflammatory/proresolution cytokines. These findings suggest that signaling through TRPV4, triggered by changes in extracellular matrix stiffness, cooperates with LPS-induced signals to mediate macrophage phagocytic function and lung injury resolution. These mechanisms are likely to be important in regulating macrophage function in the context of pulmonary infection and fibrosis., (Copyright © 2015 by The American Association of Immunologists, Inc.)

The importance of Ca(2+) signalling and temperature in the context of T cell activation is well known. However, the molecular identities of key players involved in such critical regulations are still unknown. In this work we explored the endogenous expression of transient receptor potential vanilloid (TRPV) channels, a group of thermosensitive and non-selective cation channels, in T cells. Using flow cytometry and confocal microscopy, we demonstrate that members belonging to the TRPV subfamily are expressed endogenously in the human T cell line Jurkat, in primary human T cells and in primary murine splenic T cells. We also demonstrate that TRPV1- and TRPV4-specific agonists, namely resiniferatoxin and 4α-phorbol-12,13-didecanoate, can cause Ca(2+) influx in T cells. Moreover, our results show that expression of these channels can be upregulated in T cells during concanavalin A-driven mitogenic and anti-CD3/CD28 stimulated TCR activation of T cells. By specific blocking of TRPV1 and TRPV4 channels, we found that these TRPV inhibitors may regulate mitogenic and T cell receptor mediated T cell activation and effector cytokine(s) production by suppressing tumour necrosis factor, interleukin-2 and interferon-γ release. These results may have broad implications in the context of cell-mediated immunity, especially T cell responses and their regulations, neuro-immune interactions and molecular understanding of channelopathies., (© 2015 FEBS.)

The transient receptor potential vanilloid type 1 (TRPV1) channel, a ligand-gated cation channel of the TRP subfamily, can be activated by multiple stimuli, including capsaicin. Currently, cumulative studies have demonstrated an interesting link between TRPV1 and cardiovascular diseases, including hypertension. Additionally, the protective effect of TRPV1 against hypertension and its related disorders has been proved to be partly involved with the improved action of vascular smooth muscle cells (VSMCs). This review focuses on the current knowledge of TRPV1 in improving VSMC function and attenuating hypertension., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The relationship between elements of the immune system and the nervous system in the presence of bacteria has been addressed recently. In particular, the sensory vanilloid receptor 1 (transient receptor potential cation channel subfamily V member 1 (TRPV1)) and the neuropeptide calcitonin gene-related peptide (CGRP) have been found to modulate cytokine response to lipopolysaccharide (LPS) independently of adaptive immunity. In this review we discuss mucosal homeostasis in the gastrointestinal tract where bacterial concentration is high. We propose that the Gram-negative bacterial receptor Toll-like receptor 4 (TLR4) can activate TRPV1 via intracellular signaling, and thereby induce the subsequent release of anti-inflammatory CGRP to maintain mucosal homeostasis.

Objective: To compare the intervention effects of four traditional Chinese medicines (TCMs) with typical cold or hot property on body temperature and temperature-sensitive transient receptor potential ion channel proteins (TRPs) of rats with yeast-induced fever., Method: The pyrexia model was induced by injecting yeast suspension subcutaneously. Totally 108 male SD rats were randomly divided into the normal group, the model group, the Rhei Radix et Rhizoma treated group, the Coptidis Rhizoma treated group, the Euodiae Fructus treated group, and the Alpiniae Officinarum Rhizoma treated group, with 18 rats in each group. At the 4 h, 8 h and 12 h after injection of yeast, the rats were sacrificed to collect their hypothalamus and dorsal root ganglion. The expressions of TRPV1 and TRPM8 were detected by immunohistochemistry and Western blot method., Result: Compared with the normal group, after injection of yeast, the temperature of rats in the model group notably increased, and reached the peak at 8 h (P < 0.01). The TRPV1 level in hypothalamus and dorsal root ganglia (DRG) of the model group significantly increased, whereas the TRPM8 level significantly reduced. Compared with the model group, the Rhei Radix et Rhizoma group and the Coptidis Rhizoma group showed significant decrease in the high body temperature of rats caused by yeast, down-regulation in the expression of TRPV1, and up-regulation in the expression of TRPM8 (P < 0.05 or P < 0.01). Euodiae Fructus and Alpiniae Officinarum Rhizoma had no significant effect on either temperature or TRPs of fever rats., Conclusion: Rhei Radix et Rhizoma and Coptidis Rhizoma, both are TCMs with cold property, can reduce the temperature of fever rats induced by yeast, which may be related to their effective regulation of TRPV1 and TRPM8 in hypothalamus and DRG, while Euodiae Fructus and Alpiniae Officinarum Rhizoma had no relevant effect.

On the basis of the electrophysiological research carried out with immunohystochemical methods on rats, it is found, that introduction of products of mast cell degranulation into blood as well as endogenous release of mast cell mediators with either the compound 48/80 or introduction of egg albumin to presensitized rats, enhances activity of mesenteric afferent nerve fibers. The obtained data provide evidence that intestinal afferents contribute an early signal to the brain regarding potential pathogens. The question of whether or not the intrinsic enteric neurons are involved in these processes, however, has not been carefully studied. So we investigated this problem and found that the enteric neurons express receptor of innate immunity TLR4 and nociceptive vanilloid receptor TRPV1, by means ofimmunohistochemical method. The analysis of neurons distribution revealed that vanilloid receptors are expressed by neurons localized mainly in myenteric plexus whereas TLR4-immunoreactive neurons generally are present in submucous plexus. It is also established coexpression of both receptors in the single intrinsic enteric neuron. In conclusion, our findings indicate that sensory terminals of external afferent fibers as well as intrinsic neurons of intestine can modulate reactions of the organism to endotoxins and thus may be involved in reception of inflammatory and immune responses.

Chronic inflammatory diseases are accompanied by a systemic response of the body, necessary to redirect energy-rich fuels to the activated immune system and to induce volume expansion. The systemic response is switched on by two major pathways: (a) circulating cytokines enter the brain, and (b) signals via sensory nerve fibers are transmitted to the brain. Concerning item b, sensory nerve terminals are equipped with a multitude of receptors that sense temperature, inflammation, osmolality, and pain. Thus, they can be important to inform the brain about peripheral inflammation. Central to these sensory modalities are transient receptor potential channels (TRP channels) on sensory nerve endings. For example, TRP vanilloid 1 (TRPV1) can be activated by heat, inflammatory factors (e.g., protons, bradykinin, anandamide), hyperosmolality, pungent irritants, and others. TRP channels are multimodal switches that transmit peripheral signals to the brain, thereby inducing a systemic response. It is demonstrated how and why these TRP channels (TRPV1, TRP ankyrin type 1 (TRPA1), and TRP melastatin type 8 (TRPM8)) are important to start up a systemic response of energy expenditure, energy allocation, and water retention and how this is linked to a continuously activated immune system in chronic inflammatory diseases.

A subgroup of the transient receptor potential (TRP) channels, including vanilloid 1 (TRPV1), TRPV2, TRPV3, TRPV4, and TRP ankyrin 1 (TRPA1), is expressed in cutaneous peptidergic somatosensory neurons, and has been found in skin non-neuronal cells, such as keratinocytes. Different cancer cells express TRPs, where they may exert either pro- or antitumorigenic roles. Expression and function of TRPs in skin cancers have been, however, poorly investigated. Here, we have studied the distribution and expression of TRPs by immunohistochemistry and messenger RNA (mRNA) in human healthy skin and human keratinocytic tumors, including intraepidermal proliferative disorders (solar keratosis (SK) and Bowen's disease), and non-melanoma skin cancer (NMSC; basal cell and squamous cell carcinomas). Similar TRPV1, TRPV2, and TRPV3 staining was found in keratinocytes from healthy and tumor tissues. TRPA1 staining was increased solely in SK samples. However, the marked TRPV4 staining and TRPV4 mRNA expression, observed in healthy or inflamed skin, was abrogated both in premalignant lesions and NMSC. In a human keratinocyte cell line (HaCaT), TRPV4 stimulation released IL-8, which in turn downregulated TRPV4 expression. Selective reduction in TRPV4 expression could represent an early biomarker of skin carcinogenesis. Whether the cytokine-dependent, autocrine pathway that results in TRPV4 downregulation contributes to NMSC mechanism remains to be determined.

Background: Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear., Objective: We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch., Methods: We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects., Results: Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo., Conclusion: IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma., (Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Transient receptor potential vanilloid 2 (TRPV2) is a Ca(2+)-permeable nonselective cation channel proposed to play a critical role in a wide array of cellular processes. Although TRPV2 surface expression was originally determined to be sensitive to growth factor signaling, regulated trafficking of TRPV2 has remained controversial. TRPV2 has proven difficult to study due to the lack of specific pharmacological tools to modulate channel activity; therefore, most studies of the cellular function of TRPV2 rely on immuno-detection techniques. Polyclonal antibodies against TRPV2 have not been properly validated and characterized, which may contribute to conflicting results regarding its function in the cell. Here, we developed monoclonal antibodies using full-length TRPV2 as an antigen. Extensive characterization of these antibodies and comparison to commonly used commercially available TRPV2 antibodies revealed that while monoclonal antibodies generated in our laboratory were suitable for detection of endogenous TRPV2 by western blot, immunoprecipitation and immunocytochemistry, the commercially available polyclonal antibodies we tested were not able to recognize endogenous TRPV2. We used our newly generated and validated TRPV2 antibodies to determine the effects of insulin-like growth factor 1 (IGF-1) on TRPV2 surface expression in heterologous and endogenous expression systems. We found that IGF-1 had little to no effect on trafficking and plasma membrane expression of TRPV2. Overall, these new TRPV2 monoclonal antibodies served to dispel the controversy of the effects of IGF-1 on TRPV2 plasma membrane expression and will clarify the role TRPV2 plays in cellular function. Furthermore, our strategy of using full-length tetrameric TRP channels may allow for the generation of antibodies against other TRP channels of unclear function.

The universality of anti-inflammation in moxibustion is analyzed in this article from its adaptation disease and ancient documentary records. The specificity of anti-inflammation in moxibustion is pointed out from its disease series research and scientific fact that moxibustion could be used for heat syndrome. The integrity of anti-inflammation in moxibustion is explained by series research result that four basic circulations of moxibustion for chronic inflammation are all effective. The two-way characteristic of moxibustion anti-inflammation is explained from the fact that moxibustion has regulation function both for excess and insufficiency of inflammation to demonstrate the effect mechanism of warming-dredging in moxibustion lies in its anti-inflammation. At last, the relevant possible mechanism between moxibustion anti-inflammation and transient receptor potential vanilloid (TRPV) is proposed. The effect mechanism of warming-dredging in moxibustion lies in anti-inflammation, which could provide theoretic basis for prevention and treatment of moxibustion for serious diseases.

The expression of transient receptor potential vanilloid type 1 channel (TRPV1) in the enteric nervous system is still the subject of debate. Although a number of studies have reported that TRPV1 is limited to extrinsic afferent fibers, other studies argue for an intrinsic expression of TRPV1. In the present study, reverse transcriptase PCR was employed to establish the expression of TRPV1 mRNA throughout the gastrointestinal tract. Using two antibodies directed against different epitopes of TRPV1, we were able to show at the protein level that the observed distribution pattern of TRPV1 is dependent on the antibody used in the immunohistochemical staining. A first antibody indeed mainly stained neuronal fibers, whereas a second antibody exclusively stained perikarya of enteric neurons throughout the mouse gastrointestinal tract. We argue that these different distribution patterns are due to the antibodies discriminating between different modulated forms of TRPV1 that influence the recognition of the targeted immunogen and as such distinguish intracellular from plasmalemmal forms of TRPV1. Our study is the first to directly compare these two antibodies within the same species and in identical conditions. Our observations underline that detailed knowledge of the epitope that is recognized by the antibodies employed in immunohistochemical procedures is a prerequisite for correctly interpreting experimental results.

Background: The presence of transient receptor potential vanilloid 2 (TRPV2) in human peripheral blood cells may suggest a role under pathological conditions. The aim of this study was to explore the relationship between the expression profile of TRPV2 gene and childhood asthma in the north of China. The effects of allergens exposure on the expression of TRPV2 gene were also investigated., Methods: Sixty asthmatics children confirmed by physician diagnosis and 60 healthy children as a control group were recruited. Serum total IgE and specific IgE were measured. Using quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR), TRPV2 was detected in total RNA extracted from peripheral blood lymphocytes. Student's t-test and chi-square test were used to analyze the relationship between TRPV2 transcript and different parameter variables on susceptibility of childhood asthma. Multiple logistic regression was used to analyze the associations between TRPV2 gene and allergens., Results: The expression level of TRPV2 gene was increased 2.6 times in asthmatic children compared with controls (p < .01). The up-regulation of TRPV2 gene and sensitization to one of three the allergens-spring pollen, dust mite, and dog and cat hair-were correlated with childhood asthma. In addition, the hypersensitivity to spring pollen, cockroach, and dust mite and up-regulation of TRPV2 gene expression may be the risk factors for the childhood asthma in Beijing., Conclusions: The increased expression of TRPV2 gene in peripheral lymphocytes is closely correlated with childhood asthma in the north of China. This study provides a potential new biomarker of childhood asthma and lays the basis for further clarification of the pathogenesis underlying asthma.

Autophagy is a highly conserved process involved in lymphocyte development and differentiation. Herein, we demonstrated for the first time that triggering of TRPV1 by the specific agonist CPS induces autophagy in mouse thymocytes. TRPV1-dependent autophagy required [Ca(2+)](i) and ROS generation, resulting in AMPK activation. CPS specifically increased Atg4C mRNA expression and induced oxidation of Atg4C protein by ROS generation. TRPV1-triggered autophagy was Atg6/Beclin-1-dependent, as demonstrated by the use of Beclin-1(+/-) transgenic mice, and involved ROS- and AMPK-mediated up-regulation of Beclin-1 expression. Autophagy is activated as a prosurvival process, as its inhibition triggered apoptosis of thymocytes: this effect was accompanied by down-regulation of Atg4C, Bcl-X(L), and Irgm1 mRNA expression, decreased Bcl-X(L) and Beclin-1 protein levels, and caspase-3 activation, suggesting the existence of a molecular interplay between autophagic and apoptotic programs. TRPV1 activation by CPS altered the expression of CD4 and CD8α antigens, inducing the development of DP(dull). Interestingly, we found that CPS induces autophagy of DP(dull) cells, and inhibition of CPS-induced autophagy by the 3-MA autophagic inhibitor induces apoptosis of DP(dull) cells, suggesting the presence of an interplay between autophagic survival and apoptotic cell death. Overall, our findings suggest that DP(dull) cells constitute a distinct thymocyte subpopulation involved in the homeostatic control of cellularity and in the responses to chemical stress signals during thymocyte maturation, via regulating autophagy and apoptosis in a TRPV1-dependent manner.

Medical applications of nanotechnology typically focus on drug delivery and biosensors. Here, we combine nanotechnology and bioengineering to demonstrate that nanoparticles can be used to remotely regulate protein production in vivo. We decorated a modified temperature-sensitive channel, TRPV1, with antibody-coated iron oxide nanoparticles that are heated in a low-frequency magnetic field. When local temperature rises, TRPV1 gates calcium to stimulate synthesis and release of bioengineered insulin driven by a Ca(2+)-sensitive promoter. Studying tumor xenografts expressing the bioengineered insulin gene, we show that exposure to radio waves stimulates insulin release from the tumors and lowers blood glucose in mice. We further show that cells can be engineered to synthesize genetically encoded ferritin nanoparticles and inducibly release insulin. These approaches provide a platform for using nanotechnology to activate cells.

TRPV1 and TRPV3 are two heat-sensitive ion channels activated at distinct temperature ranges perceived by human as hot and warm, respectively. Compounds eliciting human sensations of heat or warmth can also potently activate these channels. In rodents, TRPV3 is expressed predominantly in skin keratinocytes, whereas in humans TRPV1 and TRPV3 are co-expressed in sensory neurons of dorsal root ganglia and trigeminal ganglion and are known to form heteromeric channels with distinct single channel conductances as well as sensitivities to TRPV1 activator capsaicin and inhibitor capsazepine. However, how heteromeric TRPV1/TRPV3 channels respond to heat and other stimuli remains unknown. In this study, we examined the behavior of heteromeric TRPV1/TRPV3 channels activated by heat, capsaicin, and voltage. Our results demonstrate that the heteromeric channels exhibit distinct temperature sensitivity, activation threshold, and heat-induced sensitization. Changes in gating properties apparently originate from interactions between TRPV1 and TRPV3 subunits. Our results suggest that heteromeric TRPV1/TRPV3 channels are unique heat sensors that may contribute to the fine-tuning of sensitivity to sensory inputs.

Vanilloid receptor 1 (VR1) is expressed on immune cells as well as on sensory neurons. Here we report that VR1 can regulate immunological events in the gut in response to its ligand Capsaicin (CP), a nutritional factor, the pungent component of chili peppers. Oral administration of CP attenuates the proliferation and activation of autoreactive T cells in pancreatic lymph nodes (PLNs) but not other lymph nodes, and protects mice from development of type 1 diabetes (T1D). This is a general phenomenon and not restricted to one particular strain of mice. Engagement of VR1 enhances a discreet population of CD11b(+)/F4/80(+) macrophages in PLN, which express anti-inflammatory factors interleukin (IL)-10 and PD-L1. This population is essential for CP-mediated attenuation of T-cell proliferation in an IL-10-dependent manner. Lack of VR1 expression fails to inhibit proliferation of autoreactive T cells, which is partially reversed in (VR1(+/+) → VR1(-/-)) bone marrow chimeric mice, implying the role of VR1 in crosstalk between neuronal and immunological responses in vivo. These findings imply that endogenous ligands of VR1 can have profound effect on gut-mediated immune tolerance and autoimmunity by influencing the nutrient-immune interactions.