TRPV1 Research Articles

Flow-dependent regulation of rat mesenteric lymphatic vessel contractile response requires activation of endothelial TRPV4 channels.

The objective of our study is to evaluate the involvement of the transient receptor potential vanilloid 4 (TRPV4) in the alteration of lymphatic pumping in response to flow and determine the signaling pathways involved. We used immunofluorescence imaging and western blotting to assess TRPV4 expression in rat mesenteric lymphatic vessels. We examined inhibition of TRPV4 with HC067047, nitric oxide synthase (NOS) with L-NNA and cyclooxygenases (COXs) with indomethacin on the contractile response of pressurized lymphatic vessels to flow changes induced by a stepwise increase in pressure gradients, and the functionality of endothelial TRPV4 channels by measuring the intracellular Ca2+ response of primary lymphatic endothelial cell cultures to the selective agonist GSK1016790A. TRPV4 protein was expressed in both the endothelial and the smooth muscle layer of rat mesenteric lymphatics with high endothelial expression around the valve sites. When maintained under constant transmural pressure, most lymphatic vessels displayed a decrease in contraction frequency under conditions of flow and this effect was ablated through inhibition of NOS, COX or TRPV4. Our findings demonstrate a critical role for TRPV4 in the decrease in contraction frequency induced in lymphatic vessels by increases in flow rate via the production and action of nitric oxide and dilatory prostanoids.

Osteochondrodysplasia and the c.1024G>T variant of TRPV4 gene in Scottish Fold cats: genetic and radiographic evaluation.

The objectives of this study were to investigate the c.1024G>T SNP in the TRPV4 gene in Scottish Straight and Fold cats, and to evaluate the pattern of skeletal phenotype and the evolution of radiological signs of Scottish Fold osteochondrodysplasia (SFOCD) over time in heterozygous subjects. DNA was obtained from blood samples of 17 cats (Scottish Fold: n = 12; Scottish Straight: n = 5) and subsequently genotyped by sequencing in a 249 bp region of the TRPV4 gene (exon 6), including the known c.1024G>T causative mutation for osteochondrodysplasia. Orthopaedic and radiographic analyses were performed on animals carrying the mutant allele. Genotyping by sequencing confirmed that all and only the Scottish Fold cats carried the mutant allele in a heterozygous asset. Furthermore, two other exon variants, already described in the literature as silent variants, were found in some of the sampled cats. Comparative orthogonal radiographic views of the shoulder, elbow, carpus, hip, stifle and tarsus were obtained. A mediolateral projection of the thoracic and lumbar column was also performed. Three out of four cats were clinically and radiographically examined again 1.5 years later. Although the presence of the mutant allele in all the tested Scottish Fold cats was confirmed, only 1/12 showed clinical signs of SFOCD. Furthermore, no cats in the 1.5-year follow-up showed skeletal changes. Although significant, the c.1024G>T mutation in the TRPV4 gene, supposedly, is not the only cause or risk of developing SFOCD.

Piperine Attenuates Bmal1-Mediated Glucose Metabolism Disorder in a Trpv1-Dependent Manner in HepG2 Cells.

Piperine (PIP), a pungent alkaloid found in black pepper, has various pharmacological effects by activating the transient receptor potential vanilloid 1 (TRPV1) receptor. In this study, the regulating effect of PIP on glucose metabolism and the underlying mechanism were examined using an insulin-resistant cell model. Results showed that PIP alleviated glucosamine (GlcN)-induced glucose metabolism disorder (from 59.19 ± 1.90 to 88.36 ± 6.57%), restored cellular redox balance (from 148.43 ± 3.52 to 110.47 ± 3.52%), improved mitochondrial function (from 63.76 ± 4.87 to 85.98 ± 5.12%), and mitigated circadian disruption in HepG2 cells via the mediation of circadian clock gene Bmal1. After the knockdown of the Trpv1 gene, the modulating effect of PIP on Bmal1-mediated glucose metabolism was weakened, indicating that PIP alleviated Bmal1-involved insulin resistance and circadian misalignment in a Trpv1-dependent manner in HepG2 cells.

A Novel Flp Reporter Mouse Shows That TRPA1 Expression Is Largely Limited to Sensory Neuron Subsets.

Transient receptor potential ankyrin 1 (TRPA1) is a polymodal cation channel that is activated by electrophilic irritants, oxidative stress, cold temperature, and GPCR signaling. TRPA1 expression has been primarily identified in subsets of nociceptive sensory afferents and is considered a target for future analgesics. Nevertheless, TRPA1 has been implicated in other cell types including keratinocytes, epithelium, enterochromaffin cells, endothelium, astrocytes, and CNS neurons. Here, we developed a knock-in mouse that expresses the recombinase FlpO in TRPA1-expressing cells. We crossed the TRPA1Flp mouse with the R26ai65f mouse that expresses tdTomato in a Flp-sensitive manner. We found tdTomato expression correlated well with TRPA1 mRNA expression and sensitivity to TRPA1 agonists in subsets of TRPV1 (transient receptor potential vanilloid receptor type 1)-expressing neurons in the vagal ganglia and dorsal root ganglia (DRGs), although tdTomato expression efficiency was limited in DRG. We observed tdTomato-expressing afferent fibers centrally (in the medulla and spinal cord) and peripherally in the esophagus, gut, airways, bladder, and skin. Furthermore, chemogenetic activation of TRPA1-expressing nerves in the paw evoked flinching behavior. tdTomato expression was very limited in other cell types. We found tdTomato in subepithelial cells in the gut mucosa but not in enterochromaffin cells. tdTomato was also observed in supporting cells within the cochlea, but not in hair cells. Lastly, tdTomato was occasionally observed in neurons in the somatomotor cortex and the piriform area, but not in astrocytes or vascular endothelium. Thus, this novel mouse strain may be useful for mapping and manipulating TRPA1-expressing cells and deciphering the role of TRPA1 in physiological and pathophysiological processes.

Inhibition of cutaneous heat-sensitive Ca2+ -permeable transient receptor potential vanilloid 3 channels alleviates UVB-induced skin lesions in mice.

Ultraviolet B (UVB) radiation causes skin injury by trigging excessive calcium influx and signaling cascades in the skin keratinocytes. The heat-sensitive Ca2+ -permeable transient receptor potential vanilloid 3 (TRPV3) channels robustly expressed in the keratinocytes play an important role in skin barrier formation and wound healing. Here, we report that inhibition of cutaneous TRPV3 alleviates UVB radiation-induced skin lesions. In mouse models of ear swelling and dorsal skin injury induced by a single exposure of weak UVB radiation, TRPV3 genes and proteins were upregulated in quantitative real-time PCR and Western blot assays. In accompany with TRPV3 upregulations, the expressions of proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were also increased. Knockout of the TRPV3 gene alleviates UVB-induced ear swelling and dorsal skin inflammation. Furthermore, topical applications of two selective TRPV3 inhibitors, osthole and verbascoside, resulted in a dose-dependent attenuation of skin inflammation and lesions. Taken together, our findings demonstrate the causative role of overactive TRPV3 channel function in the development of UVB-induced skin injury. Therefore, topical inhibition of TRPV3 may hold potential therapy or prevention of UVB radiation-induced skin injury.

Angiotensin II induces endothelial dysfunction and vascular remodeling by downregulating TRPV4 channels

Angiotensin II (Ang II) is a potent vasoconstrictor of vascular smooth muscle cells (VSMC) and is implicated in hypertension, but it's role in the regulation of endothelial function is not well known. We and others have previously shown that mechanically activated ion channel, Transient Receptor Potential Vanilloid 4 (TRPV4) mediates flow- and/or receptor-dependent vasodilation via nitric oxide (NO) production in endothelial cells. Ang II was demonstrated to crosstalk with TRPV4 via angiotensin 1 receptor (AT1R) and β-arrestin signaling in epithelial and immortalized cells, however, the role of this crosstalk in endothelial cell function is not fully explored. Ang II treatment significantly downregulated TRPV4 protein expression and TRPV4-mediated Ca2+ influx in human EC without altering TRPV4 mRNA levels. Further, TRPV4-induced eNOS phosphorylation and NO production were significantly reduced in Ang II-treated human EC. Importantly, Ang II infusion in mice revealed that, TRPV4/p-eNOS expression and colocalization was reduced in endothelium in vivo. Finally, Ang II infusion induced vascular remodeling as evidenced by decreased lumen to wall ratio in resistant mesenteric arteries. These findings suggest that Ang II induces endothelial dysfunction and vascular remodeling via downregulation of TRPV4/eNOS pathway and may contribute to hypertension, independent of or in addition to its effect on vascular smooth muscle contraction.

Apoptosis Induction Through Increased TRPV1 Activation by Synergic Effect of Melatonin and Doxorubicin in Human Osteosarcoma and Chondrosarcoma Cell Lines

Aim: We aimed to reveal the role of doxorubicin (Dox), melatonin (Mel) and transient receptor potential Vanilloid 1 (TRPV1) channels in bone and cartilage cancer cells during the treatment process. Human Bone Osteosarcoma (Saos-2/An1) and Human Chondrosarcoma (Hs 819.T) cell lines were used to prepare in-vitro experiment models. Methods: Both cell lines were cultured at 37°C. We have separated each cell line into five groups as follows: Controls, Dox, Dox+Capsazepine (Cpz), Dox+Melatonin (Mel), and combined Dox+Mel+Cpz given group. Capsaicin and capsazepine were added to cell culture mediums to activate or inactivate the TRPV1 channels, respectively. Cytosolic calcium, apoptosis, intracellular reactive oxygen, mitochondrial depolarization, caspase-3 and caspase-9 levels were measured. Results: Increased apoptotic activity was detected in doxorubicin given cell lines (Group II) when compared with the controls (p˂0.001). There was also a significantly higher apoptotic level in Dox+Mel group (Group IV), when compared with only Dox given group (p˂0.001). TRPV1 inhibition applied groups (Group III and V) have had lower apoptotic levels than other drug administered groups (p˂0.001). Conclusion: This study has indicated that apoptotic effects of Dox and Mel on both osteosarcoma and chondrosarcoma were strictly associated to TRPV1 channels, and that TRPV1 channels played an important role in whole mitochondria dependent pathways of apoptosis, which in turn may lead to increased intracellular Ca+2 levels and mitochondrial depolarization.

TRPV4 differentially controls inflammatory cytokine networks during static and dynamic compression of the intervertebral disc.

The ion channel transient receptor potential vanilloid 4 (TRPV4) critically transduces mechanical forces in the IVD, and its inhibition can prevent IVD degeneration due to static overloading. However, it remains unknown whether different modes of loading signals through TRPV4 to regulate the expression of inflammatory cytokines. We hypothesized that TRPV4 signaling is essential duringstatic and dynamic loading to mediate homeostasis and mechanotransduction. Mouse functional spine units were isolated and either cyclically compressed for 5 days (1 Hz, 1 h, 10% strain) or statically compressed (24 h, 0.2 MPa). Conditioned media were monitored at 6 h, 24 h, 2 days, and 5 days, with and without TRPV4 inhibition. Effects of TRPV4 activation was also evaluated without loading. The media was analyzed for a panel of 44 cytokines using a microbead array and then a correlative network was constructed to explore the regulatory relationships during loading and TRPV4 inhibition. After the loading regimen, the IVDs were evaluated histologically for degeneration. Activation of TRPV4 led to an increase interleukin-6 (IL-6) family of cytokines (IL-6, IL-11, IL-16, and leukemia inhibitory factor [LIF]) and decreased the T-cell (CCL3, CCL4, CCL17, CCL20, CCL22, and CXCL10) and monocyte (CCL2 and CCL12) recruiting chemokines by the IVD. Dynamic and static loading each provoked unique chemokine correlation networks. The inhibition of TRPV4 during dynamic loading dysregulated the relationship between LIF and other cytokines, while the inhibition of TRPV4 during static loading disrupted the connectivity of IL-16 and VEGFA. We demonstrated that TRPV4 critically mediates the cytokine production following dynamic and static loading. The activation of TRPV4 upregulated a diverse set of cytokines that may suppress the chemotaxis of T-cells and monocytes, implicating the role of TRPV4 in maintaining the immune privilege of healthy IVD.

Functional knockout of the TRPV1 channel has no effect on the exercise pressor reflex in rats.

The role played by the transient receptor potential vanilloid 1 (TRPV1) channel on the thin fibre afferents evoking the exercise pressor reflex is controversial. To shed light on this controversy, we compared the exercise pressor reflex between newly developed TRPV1+/+ , TRPV1+/- and TRPV1-/- rats. Carotid arterial injection of capsaicin (0.5μg), evoked significant pressor responses in TRPV1+/+ and TRPV1+/- rats, but not in TRPV1-/- rats. In acutely isolated dorsal root ganglion neurons innervating the gastrocnemius muscles, capsaicin evoked inward currents in neurons isolated from TRPV1+/+ and TRPV1+/- rats but not in neurons isolated from TRPV1-/- rats. The reflex was evoked by stimulating the tibial nerve in decerebrated rats whose femoral artery was either freely perfused or occluded. We found no difference between the reflex in the three groups of rats regardless of the patency of the femoral artery. For example, the peak pressor responses to contraction in TRPV1+/+ , TRPV1+/- and TRPV1-/- rats with patent femoral arteries averaged 17.1 ± 7.2, 18.9 ± 12.4 and 18.4 ± 8.6mmHg, respectively. Stimulation of the tibial nerve after paralysis with pancuronium had no effect on arterial pressure, findings which indicated that the pressor responses to contraction were not caused by electrical stimulation of afferent tibial nerve axons. We also found that expression levels of acid-sensing ion channel 1 and endoperoxide 4 receptor in the L4 and 5 dorsal root ganglia were not upregulated in the TRPV1-/- rats. We conclude that TRPV1 is not needed to evoke the exercise pressor reflex in rats whose contracting muscles have either a patent or an occluded arterial blood supply. KEY POINTS: A reflex arising in contracting skeletal muscle contributes to the increases in arterial blood pressure, cardiac output and breathing evoked by exercise. The sensory arm of the reflex comprises both mechanoreceptors and metaboreceptors, of which the latter signals that blood flow to exercising muscle is not meeting its metabolic demand. The nature of the channel on the metaboreceptor sensing a mismatch between supply and demand is controversial; some believe that it is the transient receptor potential vanilloid 1 (TRPV1) channel. Using genetically engineered rats in which the TRPV1 channel is rendered non-functional, we have shown that it is not needed to evoke the metaboreflex.

Effect of Yiyuan moxibustion on urodynamics and TRPV4/ATP/P2X5 signal pathway of bladder tissue in rats with neurogenic bladder after sacral cord injury.

To observe the effect of Yiyuan moxibustion on urodynamics and the expressions of transient receptor potential vanilloid 4 (TRPV4), adenosine triphosphate (ATP), tyrosine protein kinase KIT (C-Kit) and adenosine triphosphate receptor P2X5 in bladder tissue of rats with detrusor reflex-free neurogenic bladder (NB) after sacral cord injury (SCI), so as to explore its mechanism in promoting the recovery of urination function of NB rats. Female SD rats were randomly divided into sham operation, model, Yiyuan moxibustion, Yiyuan moxibustion+inhibitor (combination) and inhibitor groups, with 12 rats in each group. The model of detruser reflex-free NB after sacral SCI was established by modified Hassan Shaker spinal cord transection method. The behavioral score of Basso Beasttie Bresnahan (BBB) and urodynamic indexes were used to evaluate the model of rats after operation. Fifteen days after modeling, Yiyuan moxibustion was applied to "Shenque" (CV8) and "Guanyuan" (CV4) for 20 min, once daily for 14 days. Rats of the inhibitor and combination groups were given intravesical instillation of HC067047 (1 mL, 1 μmol/L, 30 min). After the interventions, urodynamics was used to evaluate the bladder function of rats. HE staining was used to observe the morphology of bladder tissue. ATP content in bladder tissue was detected by colorimetric method. The positive expression rates of C-Kit and their receptor P2X5 in bladder tissue were observed by immunofluorescence double labeling method, and TRPV4, C-Kit, and P2X5 protein expression levels in bladder tissue were detected by Western blot. Compared with the sham operation group, the maximum bladder capacity and bladder compliance of rats in the model group were increased (P<0.01), the leak point pressure, ATP content, the possitive expression rates of C-Kit and P2X5, and the protein expression levels of TRPV4, C-Kit, P2X5 in bladder tissue were decreased (P<0.01). In comparison with the model and combination groups, the Yiyuan moxibustion group showed a decrease in maximum bladder capacity and bladder compliance (P<0.01), an increase in leakage point pressure, ATP content, the possitive expression rates of C-Kit and P2X5, and TRPV4, C-Kit, and P2X5 protein expression levels (P<0.01, P<0.05)；However, these indicators showed opposite trends in the inhibitor group (P<0.01, P<0.05). Yiyuan moxibustion can improve the urodynamics and bladder function in rats with bladder detrusor nonreflective after SCI, which may be related to its effect in activating the TRPV4 channel in bladder tissue, promoting the release of ATP from bladder epithelium, thus increasing the expression of bladder Cajal interstitial cells and their purinergic P2X5 receptors.

Aging is associated with impaired triggering of TRPV3-mediated cutaneous vasodilation: a crucial process for local heat exposure.

Sensing temperature is vitally important to adapt our body to environmental changes. Local warm detection is required to initiate regulation of cutaneous blood flow, which is part of the peripheral thermoregulatory mechanisms, and thus avoid damage to surrounding tissues. The mechanisms mediating cutaneous vasodilation during local heat stress are impaired with aging. However, the impact of aging on the ability of the skin to detect subtle thermal changes is unknown. Among heat-activated cation channels, transient receptor potential vanilloid 3 (TRPV3) is a thermo-sensor predominantly expressed on keratinocytes and involved in local vascular thermoregulatory mechanisms of the skin in young mice. In the present study, using a murine in vivo model of local heat exposure of the skin, we showed that heat-induced vasodilation was reduced in old mice associated with reduced expression of TRPV3 channels. We also found a decrease in expression and activity of TRPV3 channel, as well as reduced TRPV3-dependent adenosine tri-phosphate release in human primary keratinocytes from old donors. This study shows that aging alters the epidermal TRPV3 channels, which might delay the detection of changes in skin temperature, thereby limiting the mechanisms triggered for local vascular thermoregulation in the old skin.

Simulated microgravity-induced oxidative stress and loss of osteogenic potential of osteoblasts can be prevented by protection of primary cilia.

Oxidative stress has been considered to be closely related to spaceflight-induced bone loss; however, mechanism is elusive and there are no effective countermeasures. Using cultured rat calvarial osteoblasts exposed to microgravity simulated by a random positioning machine, this study addressed the hypotheses that microgravity-induced shortening of primary cilia leads to oxidative stress and that primary cilium protection prevents oxidative stress and osteogenesis loss. Microgravity was found to induce oxidative stress (as represented by increased levels of reactive oxygen species (ROS) and malondialdehyde production, and decreased activities of antioxidant enzymes), which was perfectly replicated in osteoblasts growing in NG with abrogated primary cilia (created by transfection of an interfering RNA), suggesting the possibility that shortening of primary cilia leads to oxidative stress. Oxidative stress was accompanied by mitochondrial dysfunction (represented by increased mitochondrial ROS and decreased mitochondrial membrane potential) and intracellular Ca2+ overload, and the latter was found to be caused by increased activity of Ca2+ channel transient receptor potential vanilloid 4 (TRPV4), as also evidenced by TRPV4 agonist GSK1016790A-elicited Ca2+ influx. Supplementation of HC-067047, a specific antagonist of TRPV4, attenuated microgravity-induced mitochondrial dysfunction, oxidative stress, and osteogenesis loss. Although TRPV4 was found localized in primary cilia and expressed at low levels in NG, microgravity-induced shortening of primary cilia led to increased TRPV4 levels and Ca2+ influx. When primary cilia were protected by miR-129-3p overexpression or supplementation with a natural flavonoid moslosooflavone, microgravity-induced increased TRPV4 expression, mitochondrial dysfunction, oxidative stress, and osteogenesis loss were all prevented. Our data revealed a new mechanism that primary cilia function as a controller for TRPV4 expression. Microgravity-induced injury on primary cilia leads to increased expression and overactive channel of TRPV4, causing intracellular Ca2+ overload and oxidative stress, and primary cilium protection could be an effective countermeasure against microgravity-induced oxidative stress and loss of osteogenic potential of osteoblasts.

A case of vitamin-D dependent type-1A rickets

Abstract Rickets is a disease of growing bones characterized by softening of bones as a result of defective mineralization of cartilage in the epiphyseal growth plate. The predominant cause is a deficiency or impaired metabolism of vitamin D. Some forms of rickets do not respond to regular doses of cholecalciferol, which leads to suspicion of vitamin D-dependent rickets (VDDR). VDDR is of two types: type I is due to defective renal tubular 25-hydroxyvitamin D 1-α hydroxylase, and type II is due to end-organ resistance to the active metabolite of vitamin D. Here, we describe a child with seizures and calcipenic rickets with biochemical profile suggestive of VDDR type 1 worsened by phenytoin which responded completely to calcium and calcitriol supplementation. Whole exome sequencing revealed a heterozygous missense mutation in exon 7 of the TRPV4 gene (chromosome 12,c.1292C&gt;A), whereas no mutations in CYP2R1, CYP27B1, VDR, and CYP3A4 were detected.

Novel marine natural products as effective TRPV1 channel blockers

Chronic pain management poses a formidable challenge to healthcare, exacerbated by current analgesic options' limitations and adverse effects. Transient receptor potential vanilloid 1 (TRPV1), a non-selective cation channel, has emerged as a promising target for novel analgesics. However, safety and tolerability concerns have constrained the development of TRPV1 modulators. In this study, we explored marine-derived natural products as a source of potential TRPV1 modulators using high-throughput dye-uptake assays. We identified chrexanthomycins, a family of hexacyclic xanthones, exhibited potent TRPV1 inhibitory effects, with compounds cC and cF demonstrating the most significant activity. High-resolution patch-clamp assays confirmed the direct action of these compounds on the TRPV1 channel. Furthermore, in vivo assays revealed that cC and cF effectively suppressed capsaicin-induced pain sensation in mice, comparable to the known TRPV1 inhibitor, capsazepine. Structural-activity relationship analysis highlighted the importance of specific functional groups in modulating TRPV1 activity. Our findings underscore the therapeutic potential of chrexanthomycins and pave the way for further investigations into marine-derived TRPV1 modulators for pain management.

The effect of &lt;i&gt;TRPV1&lt;/i&gt; gene polymorphism on the development of progressive course of chronic obstructive pulmonary disease

Introduction. It is known that the course of chronic obstructive pulmonary disease (COPD) may vary depending on the rate of bronchial obstruction progression. It has been shown that TRPV1 channels play an important role in the formation of some pathological syndromes typical for COPD.Aim. To study the effect of single nucleotide polymorphisms (SNPs) of TRPV1 gene on the rate of bronchial obstruction progression in COPD patients.Materials and methods. We examined 103 patients with COPD, including 47 with rapid progression of bronchial obstruction (decrease in FEV1≥50 ml/year). SNPs rs460716, rs222749, rs222747, and rs8065080 were genotyped by LATE-PCR.Results. We established that rs460716 SNP had a significant effect on the development of progressive bronchial obstruction in COPD. The CC+TT genotypes were more common among patients with progressive disease (48.9% versus 23.2%), while the heterozygous genotype was protective (p=0.006). Differences remained significant after adjusting for sex, age, pack-year index and baseline FEV1 (OR 3.2; 95%CI [1.32; 7.57], p=0.009).Conclusion. The obtained results indicate a negative influence of the homozygous genotypes carriage for TRPV1 rs460716 SNP on the course of COPD.

掌跖角化症1家系TRPV3基因突变报告

掌跖角化症1家系TRPV3基因突变报告

Physiological effects of fatty acid amides in experimental peripheral neuropathy with pharmacological blockade of GPR55 receptors

Objective. To study the effect of fatty acid amides during pharmacologic blockade of GPR55 receptors on nociceptive sensitivity and gait patterns in rats in normal and experimental peripheral neuropathy.Materials and methods. The study was carried out on male Wister rats (n=125), divided into 18 groups. The role of fatty acid amides in blockade of GPR55 receptors by administration of the antagonist O-1918 on nociceptive responses and gait parameters in healthy rats and in animals after the formation of neuropathy (NP) was studied.Results. It was found that administration of O-1918 to healthy rats and rats with neuropathy at a dose of 1 mg/kg resulted in a statistically significant decrease in the values of nociceptive reactions and gait parameters. In healthy rats and animals after ligation of the sciatic nerve against the background of blockade of GPR55 receptors PGlyA had a pronounced antinociceptive effect, which was confirmed by a significant increase in the values of nociceptive sensitivity, as well as normalization of gait.Conclusion. The analgesic effect after administration of PEA and SEA is probably the result of the interaction of the above FAAs with membrane orphan receptors. At the same time, the antinociceptive effect of PGlyA probably results from the activation of receptors belonging to another class, presumably vanilloid receptors of the first type.

TRPV4 Activation and its Intracellular Modulation Mediated by Kinin Receptors Contribute to Painful Symptoms Induced by Anastrozole.

Anastrozole, an aromatase inhibitor, induces painful musculoskeletal symptoms, which affect patients' quality of life and lead to therapy discontinuation. Efforts have been made to understand the mechanisms involved in these painful symptoms to manage them better. In this context, we explored the role of the Transient Receptor Potential Vanilloid 4 (TRPV4), a potential transducer of several nociceptive mechanisms, in anastrozole-induced musculoskeletal pain in mice. Besides, we evaluated the possible sensibilization of TRPV4 by signalling pathways downstream, PLC, PKC and PKCε from kinin B2 (B2R) and B1 (B1R) receptors activation in anastrozole-induced pain. Anastrozole caused mechanical allodynia and muscle strength loss in mice. HC067047, TRPV4 antagonist, reduced the anastrozole-induced mechanical allodynia and muscle strength loss. In animals previously treated with anastrozole, the local administration of sub-nociceptive doses of the TRPV4 (4α-PDD or hypotonic solution), B2R (Bradykinin) or B1R (DABk) agonists enhanced the anastrozole-induced pain behaviours. The sensitizing effects induced by local injection of the TRPV4, B2R and B1R agonists in animals previously treated with anastrozole were reduced by pre-treatment with TRPV4 antagonist. Furthermore, inhibition of PLC, PKC or PKCε attenuated the mechanical allodynia and muscle strength loss induced by TRPV4, B2R and B1R agonists. The generation of painful conditions caused by anastrozole depends on direct TRPV4 activation or indirect, e.g., PLC, PKC and PKCε pathways downstream from B2R and B1R activation. Thus, the TRPV4 channels act as sensors of extracellular and intracellular changes, making them potential therapeutic targets for alleviating pain related to aromatase inhibitors use, such as anastrozole.

TRPV1 Channels Are New Players in the Reticulum-Mitochondria Ca2+ Coupling in a Rat Cardiomyoblast Cell Line.

The Ca2+ release in microdomains formed by intercompartmental contacts, such as mitochondria-associated endoplasmic reticulum membranes (MAMs), encodes a signal that contributes to Ca2+ homeostasis and cell fate control. However, the composition and function of MAMs remain to be fully defined. Here, we focused on the transient receptor potential vanilloid 1 (TRPV1), a Ca2+-permeable ion channel and a polymodal nociceptor. We found TRPV1 channels in the reticular membrane, including some at MAMs, in a rat cardiomyoblast cell line (SV40-transformed H9c2) by Western blotting, immunostaining, cell fractionation, and proximity ligation assay. We used chemical and genetic probes to perform Ca2+ imaging in four cellular compartments: the endoplasmic reticulum (ER), cytoplasm, mitochondrial matrix, and mitochondrial surface. Our results showed that the ER Ca2+ released through TRPV1 channels is detected at the mitochondrial outer membrane and transferred to the mitochondria. Finally, we observed that prolonged TRPV1 modulation for 30 min alters the intracellular Ca2+ equilibrium and influences the MAM structure or the hypoxia/reoxygenation-induced cell death. Thus, our study provides the first evidence that TRPV1 channels contribute to MAM Ca2+ exchanges.

Role of TRPV1 in electroacupuncture-mediated signal to the primary sensory cortex during regulation of the swallowing function.

Electroacupuncture (EA) at the Lianquan (CV23) could alleviate swallowing dysfunction. However, current knowledge of its neural modulation focused on the brain, with little evidence from the periphery. Transient receptor potential channel vanilloid subfamily 1 (TRPV1) is an ion channel predominantly expressed in sensory neurons, and acupuncture can trigger calcium ion (Ca2+ ) wave propagation through active TRPV1 to deliver signals. The present study aimed to investigate whether TRPV1 mediated the signal of EA to the primary sensory cortex (S1) during regulation of swallowing function. Blood perfusion was evaluated by laser speckle contrast imaging (LSCI), and neuronal activity was evaluated by fiber calcium recording and c-Fos staining. The expression of TRPV1 was detected by RNA-seq analysis, immunofluorescence, and ELISA. In addition, the swallowing function was assessed by in vivo EMG recording and water consumption test. EA treatment potentiated blood perfusion and neuronal activity in the S1, and this potentiation was absent after injecting lidocaine near CV23. TRPV1 near CV23 was upregulated by EA-CV23. The blood perfusion at CV23 was decreased in the TRPV1 hypofunction mice, while the blood perfusion and the neuronal activity of the S1 showed no obvious change. These findings were also present in post-stroke dysphagia (PSD) mice. The TRPV1 at CV23 after EA treatment might play a key role in mediating local blood perfusion but was not involved in transferring EA signals to the central nervous system (CNS). These findings collectively suggested that TRPV1 may be one of the important regulators involved in the mechanism of EA treatment for improving swallowing function in PSD.