The Emerging Pro-Algesic Profile of Transient Receptor Potential Vanilloid Type 4.

Transient receptor potential vanilloid type 4 (TRPV4) channels are Ca2+-permeable non-selective cation channels which mediate a wide range of physiological functions and are activated and modulated by a diverse array of stimuli. One of this ion channel's least discussed functions is in relation to the generation and maintenance of certain pain sensations. However, in the two decades which have elapsed since the identification of this ion channel, considerable data has emerged concerning its function in mediating pain sensations. TRPV4 is a mediator of mechanical hyperalgesia in the various contexts in which a mechanical stimulus, comprising trauma (at the macro-level) or discrete extracellular pressure or stress (at the micro-level), results in pain. TRPV4 is also recognised as constituting an essential component in mediating inflammatory pain. It also plays a role in relation to many forms of neuropathic-type pain, where it functions in mediating mechanical allodynia and hyperalgesia.Here, we review the role of TRPV4 in mediating pain sensations.

Combination therapy of a TRPV2 agonist with a TNF inhibitor achieves sustained suppression of disease severity and reduced joint damage.

We aimed to compare a transient receptor potential vanilloid 2 (TRPV2) agonist with a TNF inhibitor, and to test the potential of their combination in collagen-induced arthritis (CIA) as a potential future strategy for rheumatoid arthritis (RA). Following the onset of CIA DBA1/j mice were started on treatment with either vehicle, etanercept (8 mg/kg three times a week), the TRPV2 agonist O1821 (20-30 mg/kg/day), or a combination of both. Mice were scored over a 61-day period. Synovial tissues were obtained for RNA sequencing. Mice on monotherapy with either O1821 or etanercept developed milder clinical disease. The O1821 protection was observed at an earlier time-point than in the etanercept group. The combination therapy group achieved a more robust and sustained reduction in disease severity than either monotherapy group. All treatment groups had reduced scores for synovial inflammation, synovial hyperplasia, and erosive changes, compared with controls, with the combination group achieving the most significant protection. RNA sequencing and pathway analyses of synovial tissues identified pathways and processes regulated by the TRPV2 agonist, such as chemotaxis and cytokine receptor signaling, including IL6R. The combination therapy affected additional pathways not seen in the monotherapy groups. In conclusion, the TRPV2 agonist achieved an overall similar reduction in arthritis severity and histology scores as etanercept, but the combination therapy achieved a more sustained disease control and more pronounced reduction in joint damage, suggesting a potential future option for improving disease control in RA. RNA sequencing analyses identified new pathways regulated by TRPV2, and also by the combination treatment.

A systematic review and in silico study of potential genetic markers implicated in cases of overactive bladder.

OBJECTIVE: The contribution of genetic factors to the presence of an overactive bladder is recognized. This study aimed to (1) assemble and synthesize available data from studies assessing differential gene expression in patients with overactive bladder vs controls without overactive bladder and (2) determine possible correlations and functional pathways between genes. DATA SOURCES: We searched PubMed, Ovid or Medline, and Wiley Cochrane Central Register of Controlled Trials databases between January 1, 2000, and December 15, 2021. STUDY ELIGIBILITY CRITERIA: Studies were included if gene expression was detected and quantified using molecular approaches performed on human bladder tissue specimens directly and excluded if the gene expression analysis was carried out from blood and urine specimens alone. METHODS: A systematic review was completed to identify publications that reported differently expressed gene candidates among patients with overactive bladder vs healthy individuals. Gene networking connections and pathway analysis were performed employing Metascape software, where inputs were identified from our systematic review of differentially expressed genes in overactive bladder. RESULTS: A total of 9 studies were included in the final analysis and 11 genes were identified as being up-regulated (purinergic receptor P2X 2 [P2RX2], smoothelin [SMTN], growth-associated protein 43 [GAP43], transient receptor potential cation channel subfamily M member 8 [TRPM8], cadherin 11 [CDH1], gap junction protein gamma 1 [GJC1], cholinergic receptor muscarinic 2 [CHRM2], cholinergic receptor muscarinic 3 [CHRM3], and transient receptor potential cation channel subfamily V member 4 [TRPV4]) or down-regulated (purinergic receptor P2X 2 [P2RX3] and purinergic receptor P2X 5 [P2RX5]) in patients with overactive bladder. Gene network analysis showed that genes are involved in chemical synaptic transmission, smooth muscle contraction, blood circulation, and response to temperature stimulus. Network analysis demonstrated a significant genetic interaction between TRPV4, TRPM8, P2RX3, and PR2X2 genes. CONCLUSION: Outcomes of this systematic review highlighted potential biomarkers for treatment efficacy and have laid the groundwork for developing future gene therapies for overactive bladder in clinical settings.

Colonic TRPV4 overexpression is related to constipation severity.

BACKGROUND: Chronic constipation is prevalent and involves both colon sensitivity and various changes in intestinal bacteria, particularly mucosa-associated microflora. Here we examined regulatory mechanisms of TRPV4 expression by co-culturing colon epithelial cell lines with intestinal bacteria and their derivatives. We also investigated TRPV4 expression in colon epithelium from patients with constipation. METHODS: Colon epithelial cell lines were co-cultured with various enterobacteria (bacterial components and supernatant), folate, LPS, or short chain fatty acids. TRPV4 expression levels and promoter DNA methylation were assessed using pyrosequencing, and microarray network analysis. For human samples, correlation coefficients were calculated and multiple regression analyses were used to examine the association between clinical background, rectal TRPV4 expression level and mucosa-associated microbiota. RESULTS: Co-culture of CCD841 cells with P. acnes, C. perfringens, or S. aureus transiently decreased TRPV4 expression but did not induce methylation. Co-culture with clinical isolates and standard strains of K. oxytoca, E. faecalis, or E. coli increased TRPV4 expression in CCD841 cells, and TRPV4 and TNF-alpha expression were increased by E. coli culture supernatants but not bacterial components. Although folate, LPS, IL-6, TNF-alpha, or SCFAs alone did not alter TRPV4 expression, TRPV4 expression following exposure to E. coli culture supernatants was inhibited by butyrate or TNF-alphaR1 inhibitor and increased by p38 inhibitor. Microarray network analysis showed activation of TNF-alpha, cytokines, and NOD signaling. TRPV4 expression was higher in constipated patients from the terminal ileum to the colorectum, and multiple regression analyses showed that low stool frequency, frequency of defecation aids, and duration were associated with TRPV4 expression. Meanwhile, incomplete defecation, time required to defecate, and number of defecation failures per 24 h were associated with increased E. faecalis frequency. CONCLUSIONS: Colon epithelium cells had increased TRPV4 expression upon co-culture with K. oxytoca, E. faecalis, or E. coli supernatants, as well as TNFα-stimulated TNFαR1 expression via a pathway other than p38. Butyrate treatment suppressed this increase. Epithelial TRPV4 expression was increased in constipated patients, suggesting that TRPV4 together with increased frequency of E. faecalis may be involved in the pathogenesis of various constipation symptoms.

The role of topical capsaicin gel in pain management during microfocused ultrasound treatment for neck laxity.

BACKGROUND: The transient receptor potential vanilloid 1 (TRPV1) provides a heat and pain sensation (nociception). Capsaicin, a TRPV1 agonist, has been shown to induce a refractory period in the nerve terminal expressing TRPV1 and create long-term nerve terminal defunctionalization. OBJECTIVE: To evaluate the efficacy of capsaicin for pain reduction during microfocused ultrasound with visualization (MFU-V) treatment. METHODS AND MATERIALS: A randomized, split-side study including 24 subjects was conducted. A combined 0.025% capsaicin gel and topical anesthetic were randomly applied on one side of the neck, and a topical anesthetic monotherapy was applied on the contralateral side for 30 min before MFU-V treatment. Pain score (visual analog scale, 0-10) was evaluated at T1 (before MFU-V), T2a (after the 4.5-mm transducer treatment), T2b (after the 3.0-mm transducer treatment), and T3 (after the entire treatment). Side effects were recorded. RESULTS: Mean pain scores at T2a for combined and single regimens were 5.19 (±2.26) and 6.91 (±1.72), respectively (p < 0.001). The capsaicin-treated side had a lower pain score at T2b and T3 (p < 0.001). Redness was longer on the capsaicin-treated side (112.67 vs. 10.68 min, p < 0.001). No other adverse events including contact dermatitis were reported. CONCLUSION: A single application of a combined 0.025% capsaicin gel with topical anesthesia produces a significantly lesser pain score during the MFU-V treatment. Defunctionalization of TRPV1 may explain the alleviation of painful sensations caused by heat from MFU-V.

Co-exposure to particulate matter and humidity increases blood pressure in hypertensive mice via the TRPV4-cPLA2-COX2 pathway.

Epidemiological studies have demonstrated that particulate matter (PM) can induce or exacerbate hypertension. High relative humidity has been associated with elevated blood pressure in certain regions. However, the coupling effect of humidity and PM on elevated blood pressure and the underlying mechanisms remain unknown. Herein, we aimed to explore the effects of exposure to PM and/or high relative humidity on hypertension, as well as elucidate underlying mechanisms. Male C57/BL6 mice were intraperitoneally administered NG-nitro-L-arginine methyl ester (L-NAME) to establish a hypertensive mouse model. The hypertensive mice were exposed to PM (0.15 mg/kg/day) and/or different relative humidities (45/90%) for eight weeks. Histopathological changes, systolic blood pressure (SBP), endothelial-derived contracting factors (thromboxane B2 [TXB2], Prostaglandin F2α [PGF2α], endothelin-1 [ET-1], and angiotensin II [Ang II]), and relaxing factors (prostaglandin I2 [PGI2] and nitric oxide [NO]) were measured to assess the effects of PM exposure and humidity on hypertension in mice. Levels of transient receptor potential vanilloid 4 (TRPV4), cytosolic phospholipase A2 (cPLA2), and cyclooxygenase 2 (COX2) were measured to explore their potential mechanisms. Herein, exposure to 90% relative humidity or PM alone had a slight but insignificant effect on hypertension. However, pathological changes and elevated blood pressure were markedly exacerbated following exposure to PM and 90% relative humidity. Levels of PGF2α, TXB2, and ET-1 were significantly increased, whereas the PGI2 level was substantially decreased. HC-067047-mediated blockade of TRPV4 suppressed TRPV4, cPLA2, and COX2 expression and effectively alleviated the increased blood pressure induced by exposure to PM and 90% relative humidity. These results indicate that 90% relative humidity and PM can activate the TRPV4-cPLA2-COX2 ion channel in the aorta, altering the endothelial-derived contracting and relaxing factors and enhancing blood pressure in hypertensive mice.

[Baicalin treats cerebral ischemia reperfusion-induced brain edema in rats by inhibiting TRPV4 and AQP4 of astrocytes].

This study aims to explore the pharmacodynamic effect of baicalin on rat brain edema induced by cerebral ischemia reperfusion injury and discuss the mechanism from the perspective of inhibiting astrocyte swelling, which is expected to serve as a refe-rence for the treatment of cerebral ischemia with Chinese medicine. To be specific, middle cerebral artery occlusion(suture method) was used to induce cerebral ischemia in rats. Rats were randomized into normal group, model group, high-dose baicalin(20 mg·kg~(-1)) group, and low-dose baicalin(10 mg·kg~(-1)) group. The neurobehavior, brain index, brain water content, and cerebral infarction area of rats were measured 6 h and 24 h after cerebral ischemia. Brain slices were stained with hematoxylin and eosin(HE) for the observation of pathological morphology of cerebral cortex after baicalin treatment. Enzyme-linked immunosorbent assay(ELISA) was employed to determine the content of total L-glutathione(GSH) and glutamic acid(Glu) in brain tissue, Western blot to measure the content of glial fibrillary acidic protein(GFAP), aquaporin-4(AQP4), and transient receptor potential vanilloid type 4(TRPV4), and immunohistochemical staining to observe the expression of GFAP. The low-dose baicalin was used for exploring the mechanism. The experimental results showed that the neurobehavioral scores(6 h and 24 h of cerebral ischemia), brain water content, and cerebral infarction area of the model group were increased, and both high-dose and low-dose baicalin can lower the above three indexes. The content of GSH dropped but the content of Glu raised in brain tissue of rats in the model group. Low-dose baicalin can elevate the content of GSH and lower the content of Glu. According to the immunohistochemical staining result, the model group demonstrated the increase in GFAP expression, and swelling and proliferation of astrocytes, and the low-dose baicalin can significantly improve this situation. The results of Western blot showed that the expression of GFAP, TRPV4, and AQP4 in the cerebral cortex of the model group increased, and the low-dose baicalin reduce their expression. The cerebral cortex of rats in the model group was severely damaged, and the low-dose baicalin can significantly alleviate the damage. The above results indicate that baicalin can effectively relieve the brain edema caused by cerebral ischemia reperfusion injury in rats, possibly by suppressing astrocyte swelling and TRPV4 and AQP4.

Simultaneous hyperbaric oxygen therapy during systemic chemotherapy reverses chemotherapy-induced peripheral neuropathy by inhibiting TLR4 and TRPV1 activation in the central and peripheral nervous system.

BACKGROUND AND OBJECTIVES: Chemotherapy-induced peripheral neuropathy (CIPN) is considered one of the most common sequelae in patients with cancer who experience consistent abnormal sensations or pain symptoms during or after paclitaxel (PAC) chemotherapy. Transient receptor potential vanilloid 1 (TRPV1) and toll-like receptor 4 (TLR4) have been reported to interact in the nervous system in patients with CIPN. The antinociceptive effects of hyperbaric oxygen therapy (HBOT) on CIPN was demonstrated in this study through behavior tests. Using a CIPN rat model, we examined the effects of simultaneous HBOT (SHBOT) administration during chemotherapy and discovered that SHBOT achieved better reversal effects than chemotherapy alone. MATERIALS AND METHODS: Twenty-four rats were randomly allocated to four groups: control, PAC, SHBOT, and HBOT after PAC groups. Behavior tests were performed to evaluate mechanical allodynia and thermal hyperalgesia status. Tissues from the spinal cord and dorsal root ganglions were collected, and TLR4 and TRPV1 expression and microglial activation were investigated through immunofluorescence (IF) staining. RESULTS: The mechanical and thermal behavior tests revealed that HBOT intervention during PAC treatment led to the early alleviation of CIPN symptoms and inhibited CIPN deterioration. IF staining revealed that TLR4, TRPV1, and microglial activation were all upregulated in PAC-injected rats and exhibited early and significant downregulation in SHBOT-treated rats. CONCLUSION: This study is the first to demonstrate that the use of SHBOT during PAC treatment has potential for the early suppression of CIPN initiation and deterioration, indicating that it can alleviate CIPN symptoms and may reverse CIPN in patients undergoing systemic chemotherapy.

XEN-D0501, a Novel Transient Receptor Potential Vanilloid 1 Antagonist, Does Not Reduce Cough in Patients with Refractory Cough.

RATIONALE: Heightened cough responses to inhaled capsaicin, a transient receptor potential vanilloid 1 (TRPV1) agonist, are characteristic of patients with chronic cough. However, previously, a TRPV1 antagonist (SB-705498) failed to improve spontaneous cough frequency in these patients, despite small reductions in capsaicin-evoked cough. OBJECTIVES: XEN-D0501 (a potent TRPV1 antagonist) was compared with SB-705498 in preclinical studies to establish whether an improved efficacy profile would support a further clinical trial of XEN-D0501 in refractory chronic cough. METHODS: XEN-D0501 and SB-705498 were profiled against capsaicin in a sensory nerve activation assay and in vivo potency established against capsaicin-induced cough in the guinea pig. Twenty patients with refractory chronic cough participated in a double-blind, randomized, placebo-controlled crossover study evaluating the effect of 14 days of XEN-D0501 (oral, 4 mg twice daily) versus placebo on awake cough frequency (primary outcome), capsaicin-evoked cough, and patient-reported outcomes. MEASUREMENTS AND MAIN RESULTS: XEN-D0501 was more efficacious and 1,000-fold more potent than SB-705498 at inhibiting capsaicin-induced depolarization of guinea pig and human isolated vagus nerve. In vivo XEN-D0501 completely inhibited capsaicin-induced cough, whereas 100 times more SB-705498 was required to achieve the same effect. In patients, XEN-D0501 substantially reduced maximal cough responses to capsaicin (mean change from baseline, XEN-D0501, -19.3 ± 16.4) coughs; placebo, -1.8 ± 5.8 coughs; P < 0.0001), but not spontaneous awake cough frequency (mean change from baseline, XEN-D0501, 6.7 ± 16.9 coughs/h; placebo, 0.4 ± 13.7 coughs/h; P = 0.41). CONCLUSIONS: XEN-D0501 demonstrated superior efficacy and potency in preclinical and clinical capsaicin challenge studies; despite this improved pharmacodynamic profile, spontaneous cough frequency did not improve, ruling out TRPV1 as an effective therapeutic target for refractory cough. Clinical trial registered with www.clinicaltrialsregister.eu (2014-000306-36).

Drug-like dietary vanilloids induce anticancer activity through proliferation inhibition and regulation of bcl-related apoptotic proteins.

In this study, a series of 20 structurally similar vanilloids (Vn) were tested for their antiproliferative effects against 12 human cancer cells: human breast (MCF-7 and MDA-MB-231), cervical (HeLa), ovarian (Caov-3), lung (A549), liver (HepG2), colorectal (HT-29 and HCT116), nasopharyngeal (CNE-1 and HK-1), and leukemic (K562 and CEM-SS) cancer cells. Among all the tested vanilloids, Vn16 (6-shogaol) exhibited the most potent cytotoxic effects against human colorectal cancer cells (HT-29). The apoptotic induction effects exhibited by Vn16 on HT-29 cells were confirmed using dual staining fluorescence microscopy and enzyme-linked immunosorbent assay. The effects of Vn16 on regulation of 43 apoptotic-related markers were determined in HT-29. The results suggested that 8 apoptotic markers (caspase 8, BAD, BAX, second mitochondrial-derived activator, caspase 3, survivin, bcl-2, and cIAP-2) were either upregulated or downregulated. These results further support the chemopreventive properties of foods that contain vanilloids.

First-in-human phase I study of SOR-C13, a TRPV6 calcium channel inhibitor, in patients with advanced solid tumors.

Introduction This was an open-label, dose escalation (3 + 3 design), Phase I study of SOR-C13 in patients with advanced tumors of epithelial origin. Primary objectives were to assess safety/tolerability and pharmacokinetics. Secondary goals were to assess pharmacodynamics and efficacy of SOR-C13. Methods SOR-C13 was administered IV QD on days 1-3 and 8-10 of a 21-day cycle. Doses were 2.75 and 5.5 mg/kg (20-min infusion) and 1.375, 2.75, 4.13 and 6.2 mg/kg (90-min infusion). Toxicity was assessed by National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Dose limiting toxicity (DLT) was assessed within the first treatment cycle. Tumors were evaluated, using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, after two cycles. Results Twenty-three patients were treated. No drug-related serious adverse events occurred. DLTs occurred in six patients: asymptomatic, drug-related, transient Grade 2 hypocalcemia (4 patients), and unrelated Grade 3 anemia and Grade 3 atrial fibrillation, 1 patient each. Calcium and vitamin D supplementation eliminated further Grade 2 hypocalcemia. One Grade 3 treatment emergent adverse event, urticaria, was definitely related to SOR-C13. Four possibly drug-related, Grade 3 events (alanine aminotransferase and aspartate aminotransferase elevation, headache, and hypokalemia) were observed. Of 22 evaluable patients, 54.5% showed stable disease ranging from 2.8 to 12.5 months. The best response was a 27% reduction in a pancreatic tumor with a 55% reduction in CA19-9 levels at 6.2 mg/kg. Conclusion SOR-C13 was safe and tolerated up to 6.2 mg/kg. The Maximal Tolerated Dose (MTD) was not established. Stable disease suggested antitumor activity.

Topical Ocular TRPV1 Antagonist SAF312 (Libvatrep) for Postoperative Pain After Photorefractive Keratectomy.

Purpose: Evaluation of safety and efficacy of topical ocular SAF312 (Libvatrep) in post-photorefractive keratectomy (PRK) pain. Methods: In this placebo (vehicle)-controlled, participant- and investigator-masked study, 40 participants were randomized (1:1) to two treatment sequences in a bilateral PRK crossover design (SAF312 2.5% followed by vehicle [or vice versa], one eye drop, four times daily for 72 hours after PRK). Primary endpoints were visual analog scale (VAS) pain scores at 6 hours after first drop of study drug and average VAS scores over 0 to 12 hours postoperatively. Secondary endpoints included postoperative oral rescue medication (ORM) use and adverse events (AEs). Results: All 40 participants completed the study. Both primary endpoints were met; mean difference in VAS pain scores between SAF312- and vehicle-treated eyes was -11.13 (P = 0.005, -25%) at 6 hours postoperatively and -8.56 (P = 0.017, -22%) over 0 to 12 hours. Mean VAS pain scores with SAF312 were consistently lower than with vehicle from 1 hour postoperatively up to 30 hours (P ≤ 0.10 observed in 8/11 time points). Less ORM was taken with SAF312 up to 0 to 72 hours postoperatively, with a trend of fewer participants taking ORM at 0 to 24 hours postoperatively with SAF312 versus vehicle. No serious AEs were reported. All ocular AEs were mild and transient, and none were drug related. SAF312-treated eyes showed no delay in wound healing and had a lower grade 4 conjunctival hyperemia 24 hours postoperatively versus vehicle-treated eyes. Conclusions: SAF312 was well tolerated and effective in reducing ocular pain post-PRK. Translational Relevance: Topical SAF312 presents a new therapeutic option for patients undergoing PRK.

Total alkaloids of Fritillaria unibracteata var. wabuensis bulbus ameliorate chronic asthma via the TRPV1/Ca2+/NFAT pathway.

BACKGROUND: Asthma is a chronic inflammatory disease that is challenging to treat. Fritillaria unibracteata var. wabuensis (FUW) is the plant origin for the famous Chinese antitussive medicine Fritillaria Cirrhosae Bulbus. The total alkaloids of Fritillaria unibracteata var. wabuensis bulbus (TAs-FUW) have anti-inflammatory properties and may be used to treat asthma. PURPOSE: To explore whether TAs-FUW have bioactivity against airway inflammation and a therapeutic effect on chronic asthma. METHODS: The alkaloids were extracted via ultrasonication in a cryogenic chloroform-methanol solution after ammonium-hydroxide percolation of the bulbus. UPLC-Q-TOF/MS was used to characterize the composition of TAs-FUW. An ovalbumin (OVA)-induced asthmatic mouse model was established. We used whole-body plethysmography, ELISA, western blotting, RT-qPCR, and histological analyses to assess the pulmonary pathological changes in these mice after TAs-FUW treatment. Additionally, TNF-α/IL-4-induced inflammation in BEAS-2B cells was used as an in vitro model, whereby the effects of various doses of TAs-FUW on the TRPV1/Ca2+-dependent NFAT-induced expression of TSLP were assessed. Stimulation and inhibition of TRPV1 receptors by capsaicin (CAP) and capsazepine (CPZ), respectively, were used to validate the effect of TAs-FUW. RESULTS: The UPLC-Q-TOF/MS analysis revealed that TAs-FUW mainly contain six compounds (peiminine, peimine, edpetiline, khasianine, peimisine, and sipeimine). TAs-FUW improved airway inflammation and obstruction, mucus secretion, collagen deposition, and leukocyte and macrophage infiltration, and downregulated TSLP by inhibiting the TRPV1/NFAT pathway in asthmatic mice. In vitro, the application of CPZ demonstrated that the TRPV1 channel is involved in TNF-α/IL-4-mediated regulation of TSLP. TAs-FUW suppressed TNF-α/IL-4-induced TSLP generation expression by regulating the TRPV1/Ca2+/NFAT pathway. Furthermore, TAs-FUW reduced CAP-induced TSLP release by inhibiting TRPV1 activation. Notably, sipeimine and edpetiline each were sufficient to block the TRPV1-mediated Ca2+ influx. CONCLUSION: Our study is the first to demonstrate that TNF-α/IL-4 can activate the TRPV1 channel. TAs-FUW can alleviate asthmatic inflammation by suppressing the TRPV1 pathway and thereby preventing the increase in cellular Ca2+ influx and the subsequent NFAT activation. The alkaloids in FUW may be used for complementary or alternative therapies in asthma.

Are TRPA1 and TRPV1 channel-mediated signalling cascades involved in UVB radiation-induced sunburn?

Burn injuries are underappreciated injuries associated with substantial morbidity and mortality. Overexposure to ultraviolet (UV) radiation has dramatic clinical effects in humans and is a significant public health concern. Although the mechanisms underlying UVB exposure are not fully understood, many studies have made substantial progress in the pathophysiology of sunburn in terms of its molecular aspects in the last few years. It is well established that the transient receptor potential ankyrin 1 (TRPA1), and vanilloid 1 (TRPV1) channels modulate the inflammatory, oxidative, and proliferative processes underlying UVB radiation exposure. However, it is still unknown which mechanisms underlying TRPV1/A1 channel activation are elicited in sunburn induced by UVB radiation. Therefore, in this review, we give an overview of the TRPV1/A1 channel-mediated signalling cascades that may be involved in the pathophysiology of sunburn induced by UVB radiation. These data will undoubtedly help to explain the various features of sunburn and contribute to the development of novel therapeutic approaches to better treat it.

Natural Products and some Semi-synthetic Analogues as Potential TRPV1 Ligands for Attenuating Neuropathic Pain.

Natural products and leads inspired by them have acted as a probe for successful drug discovery for many decades. Pain is an obnoxious sensory and emotional experience associated with potential tissue damage. It affects the quality of life of patients to a greater extent. Despite the availability of several agents targeting TRP receptors, none of them can proficiently alleviate neuropathic pain. TRPV1 is a prospective target for treating neuropathic pain as it is recognized to modulate the pain circuitry at the periphery and the central level. In this review, we have discussed several natural molecules, such as Capsaicinoids, Capsinoids, Piperine, Eugenol, Scutigeral, Ginsenosides, Cinnamaldehyde, Camphor, Shogaol, Gingerols, Zingerone, Allicin, Evodiamine, Allylisothiocyanate, Cannabidiol, Ricinoleic acid, Isovelleral, Capsazepine, Thapsigargin, Pellitorine, Yohimbine, Curcumin and some semi-synthetic analogues that activate TRPV1 channels and consequently, can be further harnessed for the treatment of neuropathic pain.

[Involvement of TRPV1 in CNS signaling has opened up the possibility to develop TRPV1 drug therapies]. / TRPV1 har viktig roll i hjärnan.

The discovery of TRPV1 as a receptor for capsaicin, the pungent ingredient in chili pepper, and noxious heat has triggered immense research on the role of TRP channels as polymodal receptors in sensory neuronal signaling. The rich abundance of TRPV1 in nociceptive primary afferents and its involvement in inflammatory and neuropathic pain encouraged the development of analgesics acting on TRPV1. However, the development of TRPV1 antagonists has been hampered by hyperthermia and insensitivity to noxious hot temperatures. Notably, the involvement of TRPV1 and endovanilloids in CNS signaling has opened up the possibility to develop TRPV1 drug therapies for treatment of pain alongside various CNS diseases and mental health conditions.

Review article: visceral hypersensitivity in irritable bowel syndrome: molecular mechanisms and therapeutic agents.

BACKGROUND: Although development of visceral pain is an important defensive mechanism, hypersensitivity results in a significant clinical problem and is likely to be one of the major factors involved in the pathogenesis of abdominal and chest pain in functional bowel disorders (FBDs). Understanding of the molecular mechanisms involved in peripheral sensitization of visceral nociceptors has advanced as a result of the experimental studies, especially in animal models, which have led to knowledge and identification of key mediators and receptors. AIM: To provide a comprehensive review focused on the peripheral mechanisms believed to be responsible for sensitization and potential molecular targets for a disorder which is common, distressing and has sub-optimal treatment options. METHODS: Literature review using Ovid and Pubmed from 1966. RESULTS: There is substantial interest in the development of new drugs for treatment of FBDs in the background of advances in understanding the molecular and physiological mechanisms of visceral hypersensitivity. The potential drug targets include TPRV1, ASICs, voltage-gated sodium channels, ATP, PAR-2, cannabinoid, prostaglandin, tachykinin and 5HT(3) receptors. CONCLUSION: It is anticipated that with advancing molecular understanding of the basis of visceral hypersensitivity, the next decade will see accelerated development of new molecules for treatment of functional bowel diseases.