Transient receptor potential channels as predictive marker and potential indicator of chemoresistance in colon cancer

Transient receptor potential(TRP)channels are strongly associated with colon cancer development and progression.This study leveraged a multivariate Cox regression model on publicly available datasets to construct a TRP channels-associated gene signature,with further validation of signature in real world samples from our hospital treated patient samples.Kaplan-Meier(K-M)survival analysis and receiver operating characteristic(ROC)curves were employed to evaluate this gene signature’s predictive accuracy and robustness in both training and testing cohorts,respectively.Additionally,the study utilized the CIBERSORT algorithm and single-sample gene set enrichment analysis to explore the signature’s immune infiltration landscape and underlying functional implications.The support vector machine algorithm was applied to evaluate the signature’s potential in predicting chemotherapy outcomes.The findings unveiled a novel three TRP channels-related gene signature(MCOLN1,TRPM5,and TRPV4)in colon adenocarcinoma(COAD).The ROC and K-M survival curves in the training dataset(AUC=0.761;p=1.58e-05)and testing dataset(AUC=0.699;p=0.004)showed the signature’s robust predictive capability for the overall survival of COAD patients.Analysis of the immune infiltration landscape associated with the signature revealed higher immune infiltration,especially an increased presence of M2 macrophages,in high-risk group patients compared to their low-risk counterparts.High-risk score patients also exhibited potential responsiveness to immune checkpoint inhibitor therapy,evident through increased CD86 and PD-1 expression profiles.Moreover,the TRPM5 gene within the signature was highly expressed in the chemoresistance group(p=0.00095)and associated with poor prognosis(p=0.036)in COAD patients,highlighting its role as a hub gene of chemoresistance.Ultimately,this signature emerged as an independent prognosis factor for COAD patients(p=6.48e-06)and expression of model gene are validated by public data and real-world patients.Overall,this bioinformatics study provides valuable insights into the prognostic implications and potential chemotherapy resistance mechanisms associated with TRPs-related genes in colon cancer.

New perspectives in prognostication of hepatocellular carcinoma:The role and clinical implications of transient receptor potential family genes

The study titled“Transient receptor potential-related risk model predicts prognosis of hepatocellular carcinoma patients”is a significant contribution to hepatocellular carcinoma(HCC)research,highlighting the role of transient receptor potential(TRP)family genes in the disease’s progression and prognosis.Utilizing data from The Cancer Genome Atlas database,it establishes a new risk assessment model,emphasizing the interaction of TRP genes with tumor proliferation pathways,key metabolic reactions like retinol metabolism,and the tumor immune microenvironment.Notably,the overexpression of the TRPC1 gene in HCC correlates with poorer patient survival outcomes,suggesting its potential as a prognostic biomarker and a target for personalized therapy,particularly in strategies combining immunotherapy and anti-TRP agents.

Transient receptor potential-related risk model predicts prognosis of hepatocellular carcinoma patients

BACKGROUND Members of the transient receptor potential(TRP)protein family shape oncogenic development,but the specific relevance of TRP-related genes in hepatocellular carcinoma(HCC)has yet to be defined.AIM To investigate the role of TRP genes in HCC,their association with HCC development and treatment was examined.METHODS HCC patient gene expression and clinical data were downloaded from The Cancer Genome Atlas database,and univariate and least absolute shrinkage and selection operator Cox regression models were employed to explore the TRP-related risk spectrum.Based on these analyses,clinically relevant TRP family genes were selected,and the association between the key TRP canonical type 1(TRPC1)gene and HCC patient prognosis was evaluated.RESULTS In total,28 TRP family genes were screened for clinical relevance,with multivariate analyses ultimately revealing three of these genes(TRPC1,TRP cation channel subfamily M member 2,and TRP cation channel subfamily M member 6)to be significantly associated with HCC patient prognosis(P<0.05).These genes were utilized to establish a TRP-related risk model.Patients were separated into low-and high-risk groups based on the expression of these genes,and high-risk patients exhibited a significantly poorer prognosis(P=0.001).Functional analyses highlighted pronounced differences in the immune status of patients in these two groups and associated enriched immune pathways.TRPC1 was identified as a candidate gene in this family worthy of further study,with HCC patients expressing higher TRPC1 levels exhibiting poorer survival outcomes.Consistently,quantitative,immunohistochemistry,and western blot analyses revealed increased TRPC1 expression in HCC.CONCLUSION These three TRP genes help determine HCC patient prognosis,providing insight into tumor immune status and immunological composition.These findings will help design combination therapies including immunotherapeutic and anti-TRP agents.

The transient receptor potential melastatin 2:a new therapeutical target for Parkinson's disease?

The transient receptor potential melastatin 2 is a calcium-permeable cation channel member of the TRP family. Also known as an oxidative stress-activated channel, the transient receptor potential melastatin 2 gating mechanism is dependent on reactive oxygen species. In pathological conditions, transient receptor potential melastatin 2 is overactivated, leading to a Ca~(2+) influx that alters cell homeostasis and promotes cell death. The role of transient receptor potential melastatin 2 in neurodegenerative diseases, including Alzheimer's disease and ischemia, has already been described and reviewed. However, data on transient receptor potential melastatin 2 involvement in Parkinson's disease pathology has emerged only in recent years and the issue lacks review studies that focus specifically on this topic. The present review aims to elucidate the role of the transient receptor potential melastatin 2 channel in Parkinson's disease by reviewing, summarizing, and discussing the in vitro, in vivo, and human studies published until August 2022. Here we describe fourteen studies that evaluated the transient receptor potential melastatin 2 channel in Parkinson's disease. The Parkinson's disease model used, transient receptor potential melastatin 2 antagonist and genetic approaches, and the main outcomes reported were discussed. The studies described transient receptor potential melastatin 2 activation and enhanced expression in different Parkinson's disease models. They also evidenced protective and restorative effects when using transient receptor potential melastatin 2 antagonists, knockout, or silencing. This review provides a literature overview and suggests where there is a need for more research. As a perspective point, this review shows evidence that supports transient receptor potential melastatin 2 as a pharmacological target for Parkinson's disease in the future.

Distribution of transient receptor potential vanilloid-1 channels in gastrointestinal tract of patients with morbid obesity

BACKGROUND Transient receptor potential vanilloid-1(TRPV1),a nonselective cation channel,is activated by capsaicin,a pungent ingredient of hot pepper.Previous studies have suggested a link between obesity and capsaicin-associated pathways,and activation of TRPV1 may provide an alternative approach for obesity treatment.However,data on the TRPV1 distribution in human gastric mucosa are limited,and the degree of TRPV1 distribution in the gastric and duodenal mucosal cells of obese people in comparison with normal-weight individuals is unknown.AIM To clarify gastric and duodenal mucosal expression of TRPV1 in humans and compare TRPV1 expression in obese and healthy individuals.METHODS Forty-six patients with a body mass index(BMI)of>40 kg/m^(2) and 20 patients with a BMI between 18-25 kg/m^(2) were included.Simultaneous biopsies from the fundus,antrum,and duodenum tissues were obtained from subjects between the ages of 18 and 65 who underwent esophagogastroduodenoscopy.Age,sex,history of alcohol and cigarette consumption,and past medical history regarding chronic diseases and medications were accessed from patient charts and were analyzed accordingly.Evaluation with anti-TRPV1 antibody was performed separately according to cell types in the fundus,antrum,and duodenum tissues using an immunoreactivity score.Data were analyzed using SPSS 17.0.RESULTS TRPV1 expression was higher in the stomach than in the duodenum and was predominantly found in parietal and chief cells of the fundus and mucous and foveolar cells of the antrum.Unlike foveolar cells in the antrum,TRPV1 was relatively low in foveolar cells in the fundus(4.92±0.49 vs 0.48±0.16,P<0.01,Mann-Whitney U test).Additionally,the mucous cells in the duodenum also had low levels of TRPV1 compared to mucous cells in the antrum(1.33±0.31 vs 2.95±0.46,P<0.01,Mann-Whitney U test).TRPV1 expression levels of different cell types in the fundus,antrum,and duodenum tissues of the morbidly obese group were similar to those of the control group.Staining with TRPV1 in fundus chief cells and antrum and duodenum mucous cells was higher in patients aged≥45 years than in patients<45 years(3.03±0.42,4.37±0.76,2.28±0.55 vs 1.9±0.46,1.58±0.44,0.37±0.18,P=0.03,P<0.01,P<0.01,respectively,Mann-Whitney U test).The mean staining levels of TRPV1 in duodenal mucous cells in patients with diabetes and hypertension were higher than those in patients without diabetes and hypertension(diabetes:2.11±0.67 vs 1.02±0.34,P=0.04;hypertension:2.42±0.75 vs 1.02±0.33,P<0.01 Mann-Whitney U test).CONCLUSION The expression of TRPV1 is unchanged in the gastroduodenal mucosa of morbidly obese patients demonstrating that drugs targeting TRPV1 may be effective in these patients.

Distribution profiles of transient receptor potential melastatin-related and vanilloid-related channels in prostatic tissue in rat

Aim： To investigate the expression and distribution of the members of the transient receptor potential （TRP） channel members of TRP melastatin （TRPM） and TRP vanilloid （TRPV） subfamilies in rat prostatic tissue. Methods： Prostate tissue was obtained from male Sprague-Dawley rats. Reverse transcription polymerase chain reaction （RT-PCR） and quantitative real-time polymerase chain reaction （PCR） were used to check the expression of all TRPM and TRPV channel members with specific primers. Immunohistochemistry staining for TRPM8 and TRPV1 were also performed in rat tissues. Results： TRPM2, TRPM3, TRPM4, TRPM6, TRPM7, TRPMS, TRPV2 and TRPV4 mRNA were detected in all rat prostatic tissues. Very weak signals for TRPM1, TRPVI and TRPV3 were also detected. The mRNA of TRPM5, TRPV5 and TRPV6 were not detected in all RT-PCR experiments. Quantitative real-time RT-PCR showed that TRPM2, TRPM3, TRPM4, TRPMS, TRPV2 and TRPV4 were the most abundantly expressed TRPM and TRPV subtypes, respectively. Fluorescence immunohistochemistry indicated that TRPM8 and TRPV 1 are highly expressed in both epithelial and smooth muscle cells. Conclusion： Our results demonstrate that mRNA or protein for TRPM1, TRPM2, TRPM3, TRPM4, TRPM6, TRPM7, TRPMS, TRPV1, TRPV2, TRPV3 and TRPV4 exist in rat prostatic tissue. The data presented here assists in elucidating the physiological function of TRPM and TRPV channels.

Transient receptor potential channel A1 involved in calcitonin gene-related peptide release in neurons

Transient receptor potential channel A1 is one of the important transducers of noxious stimuli in the primary afferents, which may contribute to generation of neurogenic inflammation and hyperalgesia. The present study was designed to investigate if activation of transient receptor potential channel A1 may induce calcitonin gene-related peptide release from the primary afferent neurons. We found that application of allyl isothiocyanate, a transient receptor potential channel A1 activator, caused calcitonin gene-related peptide release from the cultured rat dorsal root ganglion neurons. Knock- down of transient receptor potential channel A1 with an antisense oligodeoxynucleotide prevented calcitonin gene-related peptide release by allyl isothiocyanate application in cultured dorsal root ganglion neurons. Thus, we concluded that transient receptor potential channel A1 activation caused calcitonin gene-related peptide release in sensory neurons.

Roles of transient receptor potential channel 6 in glucose-induced cardiomyocyte injury

BACKGROUND Diabetic cardiomyopathy(DCM) is a serious complication of end-stage diabetes that presents symptoms such as cardiac hypertrophy and heart failure. The transient receptor potential channel 6(TRPC6) protein is a very important selective calcium channel that is closely related to the development of various cardiomyopathies.AIM To explore whether TRPC6 affects cardiomyocyte apoptosis and proliferation inhibition in DCM.METHODS We compared cardiac function and myocardial pathological changes in wild-type mice and mice injected with streptozotocin(STZ), in addition to comparing the expression of TRPC6 and P-calmodulin-dependent protein kinase Ⅱ(P-CaMKⅡ) in them. At the same time, we treated H9C2 cardiomyocytes with high glucose and then evaluated the effects of addition of SAR, a TRPC6 inhibitor, and KN-93, a CaMKⅡ inhibitor, to such H9C2 cells in a high-glucose environment.RESULTS We found that STZ-treated mice had DCM, decreased cardiac function, necrotic cardiomyocytes, and limited proliferation. Western blot and immunofluorescence were used to detect the expression levels of various appropriate proteins in the myocardial tissue of mice and H9C2 cells. Compared to those in the control group, the expression levels of the apoptosis-related proteins cleaved caspase 3 and Bax were significantly higher in the experimental group, while the expression of the proliferation-related proteins proliferating cell nuclear antigen(PCNA) and CyclinD1 was significantly lower. In vivo and in vitro, the expression of TRPC6 and P-CaMKⅡ increased in a high-glucose environment. However, addition of inhibitors to H9C2 cells in a high-glucose environment resulted in alleviation of both apoptosis and proliferation inhibition.CONCLUSION The inhibition of apoptosis and proliferation of cardiomyocytes in a high-glucose environment may be closely related to activation of the TRPC6/P-CaMKⅡ pathway.

Increased gene and protein expressions of the transient receptor potential vanilloid receptor 4 following sustained pure mechanical pressure on rat dorsal root ganglion neurons

Dorsal root ganglion （DRG） neurons from newborn Wistar rats cultured in vitro were pressurized with 20, 40, 80 or 120 mm Hg compressive Ioadings （1 mm Hg = 0.133 kPa） for 12, 24, 48 or 72 hours, respectively. The 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide test showed that pressures less than 80 mm Hg had no obvious impact on the activity of DRG neurons. The protein expression levels of transient receptor potential vanilloid receptor 4 （TRPV4）, transient receptor potential vanilloid receptor 1, transient receptor potential channel of melastatin type 8, and transient receptor potential subtype ankyrin 1 were assessed by western blot analysis. The mRNA expression of TRPV4 was assessed by real-time PCR. The results showed that sustained mechanical compression up-regulated TRPV4 mRNA and protein expression in the rat DRG neurons, in a time-dependent fashion. Similar changes were not found in the protein expression of transient receptor potential vanilloid receptor 1, transient receptor potential channel of melastatin type 8, and transient receptor potential subtype ankyrin 1. Images of cells using a laser scanning confocal microscope showed that the sustained mechanical pressure increased the number of responsive DRG neurons and was synergistic on the enhanced Ca^2＋ responses to the TRPV4 phorbol ester agonist 4a-phorbo112, 13-didecanoate and hypotonic solutions. These findings demonstrate that sustained mechanical compressive loading in vitro increases the expression of TRPV4 mRNA and protein in DRG neurons and sensitizes TRPV4 Ca^2＋ signals. Mechanical compression does not impact other ion channels in the transient receptor potential family.

Molecular characteristics and temperature tolerance function of the transient receptor potential in the native Bemisia tabaci AsiaII3 cryptic species

Insects are poikilothermic animals,and temperature is one of the most important abiotic factors affecting their spread and distribution.For example,differences in thermal tolerance may underlie the significant differences in geographical distributions between the native AsiaII3 and invasive MED(Mediterranean)cryptic Bemisia tabaci species in China.Transient receptor potential(TRP)channels are key components of the insect temperature perception system and act as molecular thermometers since they can be activated by specific changes in temperature.In this study,we cloned and characterized the AsiaII3 BtTRP gene and revealed its functions in the response to thermal stress.The full-length cDNA of BtTRP was 3821 bp,with a 3501-bp open reading frame encoding a 132.05-kDa protein.Comparing the deduced amino acid sequences of AsiaII3 BtTRP and MED TRP revealed five amino acid differences.In situ hybridization indicated that BtTRP might be widely expressed throughout the AsiaII3 adult body.BtTRP mRNA expression reached the highest levels after exposure to mild thermal stimuli(12 and 35°C),showing that BtTRP expression can be induced by temperature stress.Furthermore,the thermal tolerance of AsiaII3 after BtTRP dsRNA feeding was significantly lower than that of the control.Taken together,the present study highlights the importance of TRP channels for B.tabaci thermal resistance,and allows us to infer that the differences in amino acids between AsiaII3 and MED might cause the differences in thermal tolerance of these two cryptic species.This study provides a new direction for investigating geographic distribution differences between invasive and native insects.

Melastatin-related transient receptor potential 2 channel in Aβ_(42)-induced neuroinflammation: implications to Alzheimer's disease mechanism and development of therapeutics

Alzheimer’s disease （AD） is an age-related eurodegenerative disease that represents the most common cause of dementia among the elderly people. With the increasingly aging population, AD has presented an overwhelming healthcare challenge to modern society; the World Alzheimer Report 2015 has estimated that 46.8 million people worldwide lived with dementia in 2015 and this number will rise to 74.7 million in 2030 and that the total cost of dementia was 818 billion in US$ in 2015 and will reach two trillion in 2030. Post-mortem studies have identified two histopathological hallmarks in the brains of AD patients; extracellular senile plaque with elevated deposition of amyloid β （Aβ） peptides, and intracellular neurofibrillary tangle composed of hyper-phosphorylated microtubule-associated protein tau.Etiologically, progressive neuronal loss within the cerebral cortex and hippocampus regions of the brain leads to irreversible decline in, and eventually complete loss of, memory and other cognitive functions that afflict AD patients. The widely-accepted amyloid cascade hypothesis for AD pathogenesis holds that accumulation and aggregation of neurotoxic Aβ peptides, due to imbalance of their generation and clearance as a result of changes in genetic makeup, aging and/or exposure to environmental risk factors, is a major and early trigger of AD. This hypothesis has continuously gained support by preclinical and clinical studies （Selkoe and Hardy, 2016）. However, the intensive and costly drug discovery efforts over the past decades based on such a hypothesis have proved extremely frustrating in developing effective therapeutics to treat or slow down the progress of AD, highlighting the need for more research to improve our understanding towards the cellular and molecular mechanisms by which Aβ peptides bring about neurotoxicity and cognitive dysfunction.

Baicalein and Salvia officinalis Extract Upregulate Transglutaminase 1 mRNA Expression via the Activation of Transient Receptor Potential Channel V4

Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. Similar to extracellular lipids, the cornified envelope, which is a structure formed beneath the plasma membrane, contributes to the skin barrier function as a scaffold for extracellular lipids. Therefore, in this study, we focused on transglutaminase 1 (TGM1) which is the key enzyme for formation of the cornified envelope Objective: The objectives of this study were to identify compounds that could upregulate the expression of TGM1 and evaluate their underlying action mechanisms. Methods: Expression of the transient receptor potential channel vanilloid subfamily member 4 (TRPV4) at the mRNA and protein levels was estimated by PCR and western blotting. Effects of baicalein and Salvia officinalis (SO) extract on TGM1 mRNA expression were measured by PCR. The involvement of TRPV4 in TGM1 mRNA expression was evaluated by the inhibition and silencing of TRPV4. Results: TRPV4 was expressed in both basal cell-like HaCaT cells and suprabasal cell-like HaCaT cells. Baicalein and SO extract upregulated TGM1 mRNA expression in basal cell-like HaCaT cells. However, inhibition and silencing of TRPV4 abrogated the effects of baicalein and SO extract. Conclusion: Baicalein and SO extract upregulated the expression of TGM1 mRNA via the activation of TRPV4, suggesting that it may improve the skin barrier function by enhancing cornified envelope formation.

Blockade of transient receptor potential cation channel subfamily V member 1 promotes regeneration after sciatic nerve injury

The transient receptor potential cation channel subfamily V member 1（TRPV1） provides the sensation of pain（nociception）. However, it remains unknown whether TRPV1 is activated after peripheral nerve injury, or whether activation of TRPV1 affects neural regeneration. In the present study, we established rat models of unilateral sciatic nerve crush injury, with or without pretreatment with AMG517（300 mg/kg）, a TRPV1 antagonist, injected subcutaneously into the ipsilateral paw 60 minutes before injury. At 1 and 2 weeks after injury, we performed immunofluorescence staining of the sciatic nerve at the center of injury, at 0.3 cm proximal and distal to the injury site, and in the dorsal root ganglia. Our results showed that Wallerian degeneration occurred distal to the injury site, and neurite outgrowth and Schwann cell regeneration occurred proximal to the injury. The number of regenerating myelinated and unmyelinated nerve clusters was greater in the AMG517-pretreated rats than in the vehicle-treated group, most notably 2 weeks after injury. TRPV1 expression in the injured sciatic nerve and ipsilateral dorsal root ganglia was markedly greater than on the contralateral side. Pretreatment with AMG517 blocked this effect. These data indicate that TRPV1 is activated or overexpressed after sciatic nerve crush injury, and that blockade of TRPV1 may accelerate regeneration of the injured sciatic nerve.

Identification of transient receptor potential channel genes and functional characterization of TRPA1 in Spodoptera frugiperda

Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion channel family,play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.In this study,we identified 15 TRP gene loci encoding 26 transcripts in the genome of S.frugiperda and analyzed their expression profiles at different developmental stages.The results revealed that S.frugiperda possesses four TRPC genes,six TRPA genes,one TRPM gene,two TRPV genes,one TRPN gene,and one TRPML gene,while a canonical TRPP is absent.Moreover,the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45℃,and there is no significant desensitization after repeated stimuli within the same temperature range.Additionally,SfruTRPA1 is activated by certain natural chemicals,including allyl isothiocyanate(AITC)and cinnamaldehyde(CA).These findings provide valuable insights to the TRP genes in S.frugiperda.

Zhenxin Anshen formula(镇心安神方)ameliorates atopic der-matitis-like skin dysfunction in mice and in vitro via regulation of transient receptor potential vanilloid 1 and transient receptor potential ankyrin 1 in Neural pathways

OBJECTIVE:To investigate the efficacy of Zhenxin Anshen formula(镇心安神方,ZXAS)on atopic dermatitis(AD)by transient receptor potential vanilloid 1(TRPV1)and transient receptor potential ankyrin 1(TRPA1)signalling pathway in mice and in vitro.METHODS:AD-like lesions were induced by 1-chloro-2,4-dinitrobenzene(DNCB)to the shaved dorsal skin of BALB/c mice.BALB/c mice were divided into five groups:normal control,model control,cetirizine,low-,medium-,and high-dose of ZXAS.After ZXAS in-tervention,the skin lesions and blood samples were collected for hematoxylin and eosin-stained and measuring the concentrations of inflammatory cytokines.Immunoglobulin E(IgE),interleukin(IL)-4,IL-5,IL-13,and thymic stromal lymphopoietin(TSLP)were de-tected by Enzyme-linked immunosorbent assay(ELISA).The spinal cords were collected for measuring the expression of gastrin-releasing peptide receptor(GRPR),TRPV1,and TRPA1 by using immunohistochemistry,western blotting,and quantitative real-time polymerase chain reaction(qR T-PCR)analyses.In addition,3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide(MTT)assay,flow cytometry,ELISA,and Western blotting were conducted for analysis of primary dorsal root ganglia(DRG)neurons in vitro.RESULTS:ZXAS treatment improved DNCB-induced AD-like lesions through reducing dermatitis score,number of scratching and epidermal thickness,accompanied by the de-creased IgE and Th2 inflammatory cytokines.ZXAS also supressed the mRNA and protein expression of GRPR,TRPV1,and TRPA1 in the spinal cord.The medicated sera of ZXAS decreased capsaicin-induced Ca^(2+)influx and downregulated the expression of TRPV1,TRPA1,and phospholipase C in DRG neurons.CONCLUSIONS:The therapeutic effect of ZXAS on AD may be related to the regulation of TRPV1 and TRPA1 and inhibition of Ca^(2+)signals in neurons.

Role of transient receptor potential vanilloid-1 in behavioral thermoregulation of the Mongolian gerbil Meriones unguiculatus

Ambient temperature considerably affects the physiology and behavior of mammals.Thermosensory and thermoregulatory abilities play an important role in the response to changing ambient temperature in endotherms.However,the molecular mechanisms of behavioral thermoregulation remain poorly understood.Transient receptor potential vanilloid-1(TRPV1)is activated by changes in ambient temperature and is involved in acute thermoregulation.Here,we aimed to determine whether TRPV1 is involved in behavioral thermoregulation in wild rodents by conducting 2 experiments.In the first,42 adult Mongolian gerbils(Meriones unguiculatus;14 per treatment)were randomly assigned to 3 housing temperatures(4,23,and 36℃for 4 weeks.In the second,20 gerbils(10 per treatment)were randomly injected with capsaicin(TRPV1 agonist)or AMG517(TRPV1 antagonist).The results showed a significant decrease in food intake and non-shivering thermogenesis in the gerbils housed at 36℃.Additionally,there was a significant increase in the preference of gerbils housed at 4℃ to low temperatures.The expression of TRPV1 protein in the brown adipose tissue(BAT)and liver was significantly positively correlated with that of protein kinase A(PKA).The expression of TRPV1 and PKA proteins in the BAT was positively correlated with the temperature preference of the gerbils.The gerbils injected with capsaicin preferred significantly lower temperatures than the control group gerbils.These findings suggest that TRPV1 and PKA are involved in behavioral thermoregulation in Mongolian gerbils.

Serotonin receptor 2B induces visceral hyperalgesia in rat model and patients with diarrhea-predominant irritable bowel syndrome

BACKGROUND Serotonin receptor 2B(5-HT2B receptor)plays a critical role in many chronic pain conditions.The possible involvement of the 5-HT2B receptor in the altered gut sensation of irritable bowel syndrome with diarrhea(IBS-D)was investigated in the present study.AIM To investigate the possible involvement of 5-HT2B receptor in the altered gut sensation in rat model and patients with IBS-D.METHODS Rectosigmoid biopsies were collected from 18 patients with IBS-D and 10 patients with irritable bowel syndrome with constipation who fulfilled the Rome IV criteria and 15 healthy controls.The expression level of the 5-HT2B receptor in colon tissue was measured using an enzyme-linked immunosorbent assay and correlated with abdominal pain scores.The IBS-D rat model was induced by intracolonic instillation of acetic acid and wrap restraint.Alterations in visceral sensitivity and 5-HT2B receptor and transient receptor potential vanilloid type 1(TRPV1)expression were examined following 5-HT2B receptor antagonist adminis-tration.Changes in visceral sensitivity after administration of the TRPV1 antago-INTRODUCTION Irritable bowel syndrome(IBS)is a chronic functional bowel disorder characterized by recurrent abdominal pain with altered bowel habits that affects approximately 15%of the population worldwide[1].IBS significantly impacts the quality of life of patients.Although the pathogenesis of IBS is not completely understood,the role of abnormal visceral sensitivity in IBS has recently emerged[2,3].5-Hydroxytryptamine(5-HT)is known to play a key role in the physiological states of the gastrointestinal tract.Plasma 5-HT levels in IBS with diarrhea(IBS-D)patients were greater than those in healthy controls[4],suggesting a possible role of 5-HT in the pathogenesis of IBS-D.The serotonin receptor 2(5-HT2 receptor)family comprises three subtypes:5-HT2A,5-HT2B,and 5-HT2c.All 5-HT2 receptors exhibit 46%-50%overall sequence identity,and all of these receptors preferentially bind to Gq/11 to increase inositol phosphates and intracellular calcium mobilization[5].5-HT2B receptors are widely expressed throughout the gut,and experimental evidence suggests that the primary function of 5-HT2B receptors is to mediate contractile responses to 5-HT through its action on smooth muscle[6].The 5-HT2B receptor is localized to both neurons of the myenteric nerve plexus and smooth muscle in the human colon.The 5-HT2B receptor mediates 5-HT-evoked contraction of longitudinal smooth muscle[6].These findings suggest that the 5-HT2B receptor could play an important role in modulating colonic motility,which could affect sensory signaling in the gut.Other laboratories have shown that the 5-HT2B receptor participates in the development of mechanical and formalin-induced hyperalgesia[7,8].A 5-HT2B receptor antagonist reduced 2,4,6-trinitrobenzene sulfonic acid(TNBS)and stress-induced visceral hyperalgesia in rats[9,10].However,the role of the 5-HT2B receptor in IBS-D patients and in acetic acid-and wrap restraint-induced IBS-D rat models was not investigated.

Polymodal roles of transient receptor potential channels in the control of ocular function

Maintenance of intracellular Ca^(2+)levels at orders of magnitude below those in the extracellular environment is a requisite for preserving cell viability.Membrane channels contribute to such control through modulating their time-dependent opening and closing behaviour.Such regulation requires Ca^(2+)to serve as a second messenger mediating receptor control of numerous life-sustaining responses.Transient receptor potential(TRP)channels signal transduce a wide variety of different sensory stimuli to induce responses modulating cellular function.These channels are non-selective cation channels with variable Ca^(2+)selectivity having extensive sequence homology.They constitute a superfamily made up of 28 different members that are subdivided into 7 different subfamilies based on differences in sequence homology.Some of these TRP channel isotypes are expressed in the eye and localized to both neuronal and non-neuronal cell membranes.Their activation generates intracellular Ca^(2+)transients and other downstream-linked signalling events that affect numerous responses required for visual function.As there is an association between changes in functional TRP expression in various ocular diseases,there are efforts underway to determine if these channels can be used as drug targets to reverse declines in ocular function.We review here our current knowledge about the expression,function and regulation of TRPs in different eye tissues in health and disease.Furthermore,some of the remaining hurdles are described to developing safe and efficacious TRP channel modulators for use in a clinical setting.

Effects of Honokiol on Activation of Transient Receptor Potential Channel V1 and Secretion of Thymic Stromal Lymphopoietin in HaCaT Keratinocytes

Objective::This study was performed to investigate the effects of honokiol on the activation of transient receptor potential channel V1(TRPV1)and the secretion of thymic stromal lymphopoietin(TSLP)in a human benign epidermal keratinocyte line(HaCaT).Methods::HaCaT keratinocytes were cultivated and divided into six groups:capsaicin-induced model control group,capsazepine control group,solvent control group,and three honokiol treatment groups(7.81,15.63,and 31.25 mg/L of honokiol).The effect of honokiol on calcium(Ca^(2+))influx was measured by a Ca^(2+)fluorescence imaging system.The fluorescence intensity(F)of cells was measured.The rate of change in F(ΔF/F0)was calculated,and theΔF/F0-time curve was constructed.HaCaT keratinocytes were stimulated with polyinosinic:polycytidylic acid,recombinant human tumor necrosis factorα,and recombinant human interleukin 4.Different concentrations of honokiol(15.63,7.81,and 3.91 mg/L)were added to the cells in the respective honokiol groups;20 mg/L of dexamethasone or 0.5%dimethyl sulfoxide was added to the cells in the positive control group or solvent control group.The TSLP concentration in the HaCaT keratinocytes of each group was detected by enzyme-linked immunosorbent assay.Statistical analysis was performed by one-way analysis of variance and Dunnett t test.Results::The capsaicin-induced Ca^(2+)fluorescence intensity in HaCaT keratinocytes was significantly inhibited in the 31.25 mg/L honokiol group;ΔF/F0 at 45 second was 0.76 in the model control group and 0 in the 31.25 mg/L honokiol group.The TSLP level in the 15.63 and 7.81 mg/L honokiol groups was lower than that in the solvent control group(t=7.382,P=0.003,and t=2.766,P=0.023,respectively),while the TSLP level in the 3.91 mg/L honokiol group was not significantly different from that in the solvent control group(t=1.872,P=0.124).Conclusions::Honokiol inhibited the Ca^(2+)influx induced by capsaicin(TRPV1 agonist)in HaCaT keratinocytes.Honokiol has an inhibitory effect on TSLP secretion in HaCaT keratinocytes.

The relationship between the expression of transient receptor potential vanilloid 1 and the airway remodeling in elderly patients with chronic obstructive pulmonary disease

Objective To investigate the relationship between the expression of trannsient receptor potential vanilloid(TRPV1)and the severity of airway remodeling in elderly patients with chronic obstructive pulmonary disease(COPD).Methods According to airflow obstruction severity,totally 100 cases of elderly patients with