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.

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.

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.

Daikenchuto (Da-Jian-Zhong-Tang) ameliorates intestinal fibrosis by activating myofibroblast transient receptor potential ankyrin 1 channel

AIM To investigate the anti-fibrotic effects of the traditional oriental herbal medicine Daikenchuto(DKT) associated with transient receptor potential ankyrin 1(TRPA1) channels in intestinal myofibroblasts. METHODS Inflammatory and fibrotic changes were detected in a2,4,6-trinitrobenzenesulfonic acid(TNBS) chronic colitis model of wild-type and TRPA1-knockout(TRPA1-KO) mice via pathological staining and immunoblotting analysis.Ca^(2+) imaging experiments examined the effects of DKT and its components/ingredients on intestinal myofibroblast(In Myo Fib) cell TRPA1 channel function.Profibrotic factors and transforming growth factor (TGF) -β1-associated signaling were tested in an In Myo Fib cell line by q PCR and immunoblotting experiments.Samples from non-stenotic and stenotic regions of the intestines of patients with Crohn’s disease (CD) were used for pathological analysis. RESULTS Chronic treatment with TNBS caused more severe inflammation and fibrotic changes in TRPA1-KO than in wild-type mice.A one-week enema administration of DKT reduced fibrotic lesions in wild-type but not in TRPA1-KO mice.The active ingredients of DKT,i.e.,hydroxyα-sanshool and 6-shogaol,induced Ca^(2+) influxes in In Myo Fib,and this was antagonized by co-treatment with a selective TRPA1 channel blocker,HC-030031.DKT counteracted TGF-β1-induced expression of TypeⅠcollagen andα-smooth muscle actin (α-SMA) ,which were accompanied by a reduction in the phosphorylation of Smad-2 and p38-mitogen-activated protein kinase (p38-MAPK) and the expression of myocardin.Importantly,24-h incubation with a DKT active component Japanese Pepper increased the m RNA and protein expression levels of TRPA1 in In Myo Fibs,which in turn negatively regulated collagen synthesis.In the stenotic regions of the intestines of CD patients,TRPA1 expression was significantly enhanced.CONCLUSION The effects of DKT on the expression and activation of the TRPA1 channel could be advantageous for suppressing intestinal fibrosis,and benefit inflammatory bowel disease treatment.

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.

2-aminoethoxydiphenyl borate or lanthanum potentiates transient receptor potential-like channels in rat CA1 hippocampal neurons

Expression of transient receptor potential （TRP） channels is widespread with transcripts distributed throughout the brain. All TRP channel subunits are activated following phospholipase C activation and form cation-selective ion channels. Previous studies examining the existence of TRP channels in hippocampal CA1 pyramidal neurons were based on cultured neurons. Therefore, their relevance for living tissue remains unclear. In the present study, patch-clamp recordings were conducted from CA1 pyramidal neurons in hippocampal slices from 7-day-old rats. Whole-cell currents were obtained from CA1 hippocampal neurons with potentiation effects of 2-aminoethoxydiphenyl borate and lanthanum, revealing that recorded experimental currents were characteristic TRP-like channel currents. Identification of rat hippocampal mRNA transcripts of TRPC4, TRPC5, TRPV1, TRPV2, and TRPV3 channels further verified the expression of characteristic TRP-like channels on rat CA1 hippocampal neurons.

Transient Receptor Potential Ankyrin 1 Ion Channel Facilitates Acute Inflammation Induced by Surgical Incision in Mice

Background: Transient receptor potential ankyrin (TRPA) 1 is known as a peripheral initiator of acute inflammation and hyperalgesia. However, its role in the facilitation of innate immune responses followed by resolution of the inflammation triggered by a surgical incision has not been fully investigated. Therefore, we evaluated the mechanism by which TRPA1 regulates the inflammatory responses mainly facilitated by neutrophils and macrophages in the early course of wound repair after an incision. Methods: Plantar incision was performed in wild-type and TRPA1-/- mice. The infiltration of polymorphonuclear neutrophils, macrophage phenotype, and induction of inflammatory mediators were assessed for 7 days postoperatively. Results: TRPA1-/-?mice exhibited decreased infiltration of polymorphonuclear neutrophilscompared with wild-type mice on day 1. Consistently, the influx of F4/80+ iNOS+ proinflammatory M1 macrophages to incised sites was markedly decreased on day 2. Similarly, F4/80+ CD206+M2 macrophages, which regulate the resolution of inflammation and promote wound healing in the later phase of acute inflammation, were significantly decreased in TRPA1-/- compared with those in wild-type mice on day 7. In addition, the induction of heme oxygenase-1, which promotes wound healing by switching phenotype of macrophages, was decreased in the early phase of acute inflammation, whereas the expression of proinflammatory mediators such as tumor necrosis factor and cyclooxygenase-2, and 15-lipoxygenase, which are involved in the resolution of inflammation was increased in the late phase in TRPA1-/- mice. Conclusions: Early innate immune responses including neutrophil infiltration and macrophage polarization at incised sites were inhibited in TRPA1-/- mice, associated with increased pro-inflammatory mediators in later phase. Peripheral TRPA1 may facilitate the acute inflammatory process, leading to the promotion of macrophage-mediated resolution of inflammation and wound repair after a surgical incision.

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.

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.

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.

Transient receptor potential vanilloid 4-dependent calcium influx and ATP release in mouse and rat gastric epithelia

AIM: To explore the expression of transient receptor potential vanilloid 4(TRPV4) and its physiological meaning in mouse and rat gastric epithelia. METHODS: RT-PCR and immunochemistry were used to detect TRPV4 m RNA and protein expression in mouse stomach and a rat normal gastric epithelial cell line(RGE1-01), while Ca2+-imaging and electrophysiology were used to evaluate TRPV4 channel activity. ATP release was measured by a luciferin-luciferase assay. Gastric emptying was also compared between WT and TRPV4 knockout mice. RESULTS: TRPV4 m RNA and protein were detected in mouse tissues and RGE1-01 cells. A TRPV4-specific agonist(GSK1016790A) increased intracellular Ca2+ concentrations and/or evoked TRPV4-like current activities in WT mouse gastric epithelial cells andRGE1-01 cells, but not TRPV4 KO cells. GSK1016790 A or mechanical stimuli induced ATP release from RGE1-01 cells while TRPV4 knockout mice displayed delayed gastric emptying in vivo. CONCLUSION: TRPV4 is expressed in mouse and rat gastric epithelium and contributes to ATP release and gastric emptying.

Transient Receptor Potential Ion Channels in the Etiology and Pathomechanism of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disabling condition of unknown cause having multi-system manifestations. Our group has investigated the potential role of transient receptor potential (TRP) ion channels in the etiology and pathomechanism of this illness. Store-operated calcium entry (SOCE) signaling is the primary intracellular calcium signaling mechanism in non-excitable cells and is associated with TRP ion channels. While the sub-family (Canonical) TRPC has been traditionally associated with this important cellular mechanism, a member of the TRPM sub-family group (Melastatin), TRPM3, has also been recently identified as participating in SOCE in white matter of the central nervous system. We have identified single nucleotide polymorphisms (SNPs) in TRP genes in natural killer (NK) cells and peripheral blood mononuclear cells (PBMCs) in CFS/ME patients. We also describe biochemical pathway changes and calcium signaling perturbations in blood cells from patients. The ubiquitous distribution of TRP ion channels and specific locations of sub-family group members such as TRPM3 suggest a contribution to systemic pathology in CFS/ME.

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.

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.

Transient receptor potential vanilloid 1 involved in the analgesic effects of total flavonoids extracted from Longxuejie(Resina Dracaenae Cochinchinensis)

OBJECTIVE: To evaluate the analgesic effects of total flavonoids of Longxuejie(Resina Dracaenae Cochinchinensis)(TFDB) and explore the possible analgesic mechanism associated with transient receptor potential vanilloid 1(TRPV1).METHODS: Whole-cell patch clamp technique was used to observe the effects of TFDB on capsaicin-induced TRPV1 currents. Rat experiments in vivo were used to observe the analgesic effects of TFDB. Western blot and immunofluorescence experiments were used to test the change of TRPV1 expression in DRG neurons induced by TFDB.RESULTS: Results showed that TFDB inhibited capsaicin-induced TRPV1 receptor currents in acutely isolated dorsal root ganglion(DRG) neurons of rats and the half inhibitory concentration was(16.7 ± 1.6) mg/L.TFDB(2-20 mg/kg) showed analgesic activity in the phase Ⅱ of formalin test and(0.02-2 mg per paw)reduced capsaicin-induced licking times of rats. TFDB(20 mg/kg) was fully efficacious on complete Freund's adjuvant(CFA)-induced inflammatory thermal hyperalgesia and capsaicin could weaken the analgesic effects. The level of TRPV1 expressions of DRG neurons was also decreased in TFDB-treated CFA-inflammatory pain rats.CONCLUSION: All these results indicated that the analgesic effect of TFDB may contribute to their modulations on both function and expression of TRPV1 channels in DRG neurons.

TRPC1与BK-α的表达对大鼠糖尿病肾病的影响

目的 探究瞬时受体电位C1(transient receptor potential channel 1,TRPC1)蛋白和大电导钙离子激活钾通道α亚单位(large conductance Ca^(2+)-activated K^(+)channel α subunit,BK-α)蛋白对大鼠糖尿病肾病(diabetic kidney disease,DKD)的影响。方法 将SD大鼠随机分为对照组(n=15)和模型组(n=15)。利用高脂饲料和链脲佐菌素(streptozocin,STZ)构建DKD模型。采用血糖分析仪检测大鼠血糖变化;采用全自动生化分析仪检测大鼠肾功能水平;HE染色检测肾组织的病理变化以确定造模成功。实时荧光定量PCR(RT-qPCR)和蛋白免疫印迹分别检测肾组织TRPC1和BK-α的mRNA和蛋白表达水平;免疫组化检测TRPC1和BK-α的分布和表达情况。结果 模型组大鼠空腹血糖(fasting plasma glucose,FPG)、尿白蛋白排泄率(urinary albumin excretion rates,UAER)、血尿素氮(blood urea nitrogen,BUN)和肌酐(creatinine,Cr)均显著高于对照组(P <0.01);模型组大鼠肾小管内壁细胞出现膨胀现象,部分细胞脱离;可见肾小管发生病变或死亡;此外,在许多肾小管及肾间质区域发现有中性白细胞及其残骸;以上HE染色结果提示,DKD模型复制成功。TRPC1和BK-α在肾小球部位最为丰富,且模型组大鼠肾组织中TRPC1和BK-α的mRNA和蛋白水平都显著高于对照组(P <0.05)。结论 大鼠糖尿病肾病影响TRPC1和BK-α在肾组织中的分布和表达。