Mechanism of TRPC in promoting extracellular matrix deposition of glomerular mesangial cells / 西安交通大学学报(医学版)

【Objective】 To explore the role and mechanism of TRPC in promoting extracellular matrix (ECM) deposition in rat glomerular mesangial cells (HBZY-1). Methods Immunofluorescence staining was performed to observe the distribution and expression of TRPC1 and TRPC6 in HBZY-1 cells. After AngⅡ stimulation, qRT-PCR and Western blotting were used to detect the mRNA and protein expressions of Gαq/PLCβ4/TRPC signaling pathway main proteins and ECM deposition indicators (α-SMA, collagenⅢ and fibronectin). By silencing the expressions of TRPC1 and TRPC6 by RNA interference, the expressions of ECM deposition indicators were detected. Changes in [Ca2+]i influx were determined through Fluo-4AM Ca2+ imaging. 【Results】 Both TRPC1 and TRPC6 were expressed in HBZY-1, and were mainly located in cell membrane and cytoplasm. After AngⅡ stimulation, Gαq/PLCβ4/TRPC signaling pathway was activated, and the mRNA and protein expressions of Gαq, PLCβ4, TRPC1 and TRPC6 were all increased (P<0.05). [Ca2+]i influx also increased (P<0.01), and the mRNA and protein expressions of ECM deposition indicators (α-SMA, ColⅢ and Fn) were upregulated (P<0.05). Silencing the expressions of TRPC1 and TRPC6 by RNA interference led to decreased [Ca2+]i influx (P<0.05), and downregulated mRNA and protein expressions of ECM deposition indicators in HBZY-1 cells (P<0.05). The results suggested that inhibition of TRPC expressions could inhibit AngⅡ induced ECM deposition in HBZY-1 cells, which might be associated with decreased [Ca2+]i influx. 【Conclusion】 TRPC may be a novel therapeutic target of renal fibrosis.

TRPC6 involves in endoplasmic reticulum stress induced apoptosis of glomerular mesangial cells / 西安交通大学学报(医学版)

【Objective】 To explore the role and mechanism of TRPC6 in apoptosis of glomerular mesangial cells (HBZY-1) induced by endoplasmic reticulum stress (ERS). 【Methods】 The experiment groups were classified as follows: normal control (NC), thapsigargin (TG), TG+SKF96365, and TG+TRPC6 siRNA groups. Transcription and protein expressions of TRPC6 and ERS related proteins (GRP78 and Caspase12) were detected by qRT-PCR and Western blotting. Additionally, cell apoptosis was measured by flow cytometry and Hoechst33258. Finally, Fluo-4 AM Ca2+ imaging technique was used to determine changes of intracellular calcium ( [Ca2+] i) by laser scanning confocal microscope. 【Results】 Morphological changes of apoptotic cells were characterized by nuclear enrichment or nuclear fragmentation, and the apoptosis rate was increased after TG stimulation. The expressions of TRPC6 and ERS related proteins (GRP78 and Caspase12) were elevated in TG group compared with NC group (P<0.05). Pre-incubation of HBZY-1 cells with SKF96365 and TRPC6 siRNA decreased cell apoptosis (P<0.05). The entry of [Ca2+] i also increased after TG stimulation (P<0.05). The expressions of TRPC6, GRP78 and Caspase12 were downregulated compared with TG group after treatment with SKF96365 and TRPC6 siRNA accompanied by decreased [Ca2+] i (P<0.05). 【Conclusion】 Taken together, this study suggests that inhibition of TRPC6 can alleviate TG-induced HBZY-1 cell apoptosis.

Protective role and mechanism of human umbilical cord mesenchymal stem cell-derived exosome in renal ischemia-reperfusion injury / 器官移植

Objective To investigate the protective effect of human umbilical cord mesenchymal stem cell-derived exosome (hucMSC-Exo) on renal ischemia-reperfusion injury (IRI), and to clarify the critical role and regulating mechanism of transient receptor potential canonical (TRPC) 6/poly adenosine-diphosphate-ribose polymerase (PARP) 1 signaling pathway during this process. Methods The hucMSC-Exo was extracted by ultracentrifugation, and identified by transmission electron microscope (TEM), nanoparticle tracing analysis and Western blot. SD rats were randomly divided into the sham operation group (group S), sham operation+TRPC6 inhibitor SKF96365 group (group SS), renal IRI group (group IRI), exosome treatment group (group EXO) and exosome +TRPC6 inhibitor SKF96365 group (group ES), with 6 rats in each group. Serum creatinine and blood urea nitrogen levels were detected. Pathological changes of renal tissues were observed by hematoxylin-eosin (HE) staining and Paller score was calculated. The expression levels of key molecules of necroptosis in rat renal tissues, including receptor-interacting protein kinase (RIPK)1, RIPK3 and mixed-lineage kinase domain-like protein (MLKL), TRPC6 and PARP1, were detected by Western blot. Results Typical saucer-like structure was observed under TEM. Nanoparticle tracing analysis showed that the average diameter of the extracted substance was 125.9 nm. Western blot revealed that the surface markers of CD9, CD63 and CD81 were positively expressed, confirmed that the extracted substance was exosome. Compared with group S, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was worsened, Paller score was elevated, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group IRI (all P < 0.05). Compared with group IRI, the serum creatinine and blood urea nitrogen levels were down-regulated, the pathological damage of renal tissues was mitigated, Paller score was decreased, the relative expression levels of TRPC6 and PARP1 proteins were up-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were down-regulated in group EXO (all P < 0.05). Compared with group EXO, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was aggravated, Paller score was increased, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group ES (all P < 0.05). Conclusions hucMSC-Exo may alleviate the necroptosis induced by renal IRI in rat models, which is related to the activation of TRPC6/PARP1 signaling pathway.

MicroRNA-26a-5p protects against podocyte injury via inhibiting TRPC6 expression in diabetic kidney disease / 中华肾脏病杂志

Objective:To investigate the protective effect and potential mechanisms of microRNA-26a-5p (miR-26a-5p) on podocyte injury in diabetic kidney disease (DKD).Methods:(1) In vivo experiment: Four-week-old db/db mice were divided into db/db group, db/db+agomir-NC group and db/db+miR-26a-5p agomir group according to random number table method, with 10 mice in each group, and 10 db/m mice of the same week-old were set as normal control group. At the age of 10 weeks, pathological changes were observed through light and electron microscopy. Kidney weight/body weight (KW/BW), urinary albumin to creatinine ratio (ACR), fasting blood glucose (FBG) and other biochemical indicators were also detected. The position and expression of miR-26a-5p in kidney tissue were determined through fluorescence in situ hybridization and quantitative real-time PCR, while the expressions of transient receptor potential cation channel-6 (TRPC6) and Nephrin in kidney tissue were determined by Western blotting and immunohistochemistry. (2) In vitro experiment: The immortalized mouse podocytes (MPC5) were divided into 5 groups: normal glucose group, high mannitol group, high glucose group, high glucose+miR-26a-5p mimic group, and high glucose+mimic-NC group. The expressions of miR-26a-5p, TRPC6 and Nephrin were detected. Luciferase reporter assay was conducted to research the relationship of miR-26a-5p and TRPC6. Results:(1) In vivo experiment: Compared with db/m group, db/db mice exhibited lower KW/BW and disrupted conditions of ACR, FBG, total cholesterol, triglycerides and low density lipoprotein cholesterol (all P<0.01). Increased glomeruli volume, more extracellular matrix deposition, thicker basement membrane and more foot process fusion were observed by light and electron microscope. Increased expression of TRPC6 protein as well as decreased expression of Nephrin protein and miR-26a-5p were detected in kidney tissues of db/db mice ( P<0.05). Compared with db/db+agomir-NC group, db/db mice transfected by miR-26a-5p agomir exhibited less albuminuria, with less protein expression of TRPC6 and more Nephrin in kidney tissue (all P<0.05). (2) In vitro experiment: Compared with normal glucose group, high glucose-treated podocytes exhibited increased expression of TRPC6 ( P<0.05), as well as decreased expression of Nephrin ( P<0.05) and miR-26a-5p ( P<0.01). Compared with high glucose+mimic-NC group, lower expression of TRPC6 and higher expression of Nephrin were detected in podocytes transfected by miR-26a-5p mimic (both P<0.05). Luciferase reporter assay confirmed that miR-26a-5p could regulate the expression of TRPC6 precisely. Conclusions:The expression of miR-26a-5p in podocytes is down-regulated in the context of high glucose and miR-26a-5p protects podocytes from injury via inhibiting the expression of TRPC6 in DKD.

Mitochondrial Reactive Oxygen Species Elicit Acute and Chronic Itch via Transient Receptor Potential Canonical 3 Activation in Mice / 神经科学通报·英文版

Mitochondrial reactive oxygen species (mROS) that are overproduced by mitochondrial dysfunction are linked to pathological conditions including sensory abnormalities. Here, we explored whether mROS overproduction induces itch through transient receptor potential canonical 3 (TRPC3), which is sensitive to ROS. Intradermal injection of antimycin A (AA), a selective inhibitor of mitochondrial electron transport chain complex III for mROS overproduction, produced robust scratching behavior in naïve mice, which was suppressed by MitoTEMPO, a mitochondria-selective ROS scavenger, and Pyr10, a TRPC3-specific blocker, but not by blockers of TRPA1 or TRPV1. AA activated subsets of trigeminal ganglion neurons and also induced inward currents, which were blocked by MitoTEMPO and Pyr10. Besides, dry skin-induced chronic scratching was relieved by MitoTEMPO and Pyr10, and also by resveratrol, an antioxidant. Taken together, our results suggest that mROS elicit itch through TRPC3, which may underlie chronic itch, representing a potential therapeutic target for chronic itch.

Research progress on the role of transient receptor potential canonical 6 in ischemia-reperfusion injury / 器官移植

Ischemia-reperfusion injury (IRI) refers to the reperfusion injury caused by the recovery of blood supply of ischemic tissues or organs, which commonly occurs in organ transplantation and other surgical procedures. IRI may cause a series of severe clinical issues, such as delayed graft function, acute kidney injury, myocardial infarction, ischemic stroke and circulatory arrest, etc. These events yield high incidence and fatality. At present, no effective solution has been available. Transient receptor potential canonical 6 (TRPC6), a member of Ca2+ channel family, is highly expressed in multiple types of cells. It may adjust many physiological functions by regulating intracellular Ca2+ concentration, which has become an important target for developing therapeutic drugs for multiple diseases. In this article, research progresses on the introduction and function of TRPC6, the association between TRPC6 and IRI and the therapeutic prospect of TRPC6 targeted drugs in IRI were reviewed, aiming to provide novel insights into the prevention and treatment of IRI during organ transplantation

Regulation of transient receptor potential channel protein 5 in inflammation in diabetic cardiomyopathy / 中国药理学通报

Aim To investigate the effect of TRPC5 gene on the inflammation of cliabetie cardiomyopathy.Methods The biological functions of TRPC5 and the correlation between TRPC5 gene and other genes were analyzed by bioinformatics.Studies were performed in TRPC5 knockout ( TRPC5 ) and C57 mice.Mice were randomly divided into blank control and T2DM model groups, and the model was established by intraperitoneal injection of STZ (n = 10).The myocardial injury was detected by HE and Masson staining.Hie level of serum IL-1(3, IL-2, IL-6, IFN-7 and creatine kinase was examined by ELISA.Gene and protein expressions of IL-1(3, IL-2, IL-6 and TRPC5 were analysed by RT-PCR and Western blot respectively.Results By constructing the PPI network and analyses.the TRPC5 gene was identified to internet with a variety inflammatory genes and involved in immunity.The result of pathologieal section showed less myocardial damage and infiltrated immune cells in TRPC5 mice than in C57BL/6J mice.RT-PCR and serum results showed a lower expression of inflammatory factors in myocardium and serum obtained from TRPC5 model mice than in those obtained from C57BL/6J model mice.Conclusions TRPC5 participates in the development of dilated cardiomyopathy by regulating cardio- myocyte inflammation.

Research and progression of TRPC6 and proteinuria induced by obesity / 中华内分泌外科杂志

The obesity related glomerulopathology attracts more and more attention due to the proteinuria induced by podocyte injury. TRPC6,which on the slit diaphragm of podocyte, and other factors contain together of the signal translation, cell polarization and cell skeleton structure of podocyte. Therefore the ion channels become the research front filed of kidney disease from the view on electrophysiology. Under this background, we introduce the biological function of TRPC6 and review its role on proteinuria induced by obesity. At last we sum up and outlook the application of TRPC6 as a treated target in proteinuria related obesity in the future.

Protective Mechanism of Danggui Shaoyaosan on Podocytes of Nephrotic Syndrome Rats Based on AngⅡ-TRPC6 Pathway / 中国实验方剂学杂志

Objective:To explore the protective effect and the mechanism of Danggui Shaoyaosan（DSS） on angiotensin Ⅱ （AngⅡ）/transient receptor potential cation channel 6 （TRPC6） pathway in nephrotic syndrome （NS） rats. Method:In animal experiments， doxorubicin （4 mg·kg^-1 for the 1^st week and 2 mg·kg^-1 for the 2^nd week） was injected twice to the tail vein of rats to induce NS model in 160 rats， which were then randomly divided into model group （normal saline）， losartan group （30 mg·kg^-1·d^-1）， and low-（4.3 g·kg^-1·d^-1）， medium-（8.6 g·kg^-1·d^-1）， and high-dose （17.2 g·kg^-1·d^-1） DSS groups. Besides， a normal group was also set. After intervention for four weeks， ultrastructure changes of the kidney were identified by transmission electron microscopy （TEM）. The 24-hour urine protein was detected by kits. Radioimmunoassay was used to detect the content of AngⅡ and Calcineurin （CaN） in plasma. Western blot was used to detect the protein expression of TRPC6， angiotensin Ⅱ type 1 receptor （AT1R）， podocyte slit diaphragm-specific protein （Nephrin）， and cysteine-aspartic acid protease-3 （Caspase-3） in the renal cortex. Immunohistochemistry was used to detect the expression of TRPC6 and AT1R in the slit diaphragm. In cell experiments， AngⅡ stimulated MPC5 podocytes. The cells were randomly divided into a normal group， an AngⅡ group， an AngⅡ+SAR7334 （TRPC6-specific inhibitor） group， an AngⅡ+5%DSS group， an AngⅡ+10%DSS group， and an AngⅡ+15%DSS group. Western blot was used to detect the protein expression of TRPC6， AT1R， Nephrin， and Caspase-3 in podocytes. Result:Compared with the normal group， the model group showed increased 24-hour urine protein content （<italic>P</italic><0.01） and AngⅡ and CaN in plasma （<italic>P</italic><0.01）， incomplete glomerular structure， the extensive fusion of podocyte process with elevated fusion rate （<italic>P</italic><0.01）， increased expression distribution of AT1R and TRPC6 in the renal cortex， and up-regulated protein expression of AT1R， TRPC6， and Caspase-3 in renal tissues （<italic>P</italic><0.01）， and reduced Nephrin protein expression （<italic>P</italic><0.01）. Compared with model group， the losartan group and the high-dose DSS group exhibited decreased 24-hour urine protein content （<italic>P</italic><0.01） and the content of AngⅡ and CaN in plasma （<italic>P</italic><0.01）， improved glomerular structure， reduced fusion rate of podocyte process （<italic>P</italic><0.01）， diminished expression distribution of TRPC6 and AT1R in the renal cortex， declining protein expression of AT1R， TRPC6 and Caspase-3 in renal tissues （<italic>P</italic><0.01）， and elevated Nephrin protein expression （<italic>P</italic><0.01）. Additionally， compared with the normal podocytes， AngⅡ-stimulated podocytes showed increased protein expression of AT1R， TRPC6 and Caspase-3 （<italic>P</italic><0.01）， and decreased expression of Nephrin （<italic>P</italic><0.01）. Compared with the AngⅡ group， the AngⅡ+SAR7334 group displayed reduced protein expression of AT1R， TRPC6， and Caspase-3 （<italic>P</italic><0.01） and increased protein expression of Nephrin （<italic>P</italic><0.01）. Conclusion:DSS can improve the pathological characteristics of NS presumedly by inhibiting the interaction between AngⅡ and TRPC6 in podocytes and improving the structural integrity of podocytes to repair the damage of glomerular molecular barrier and slow down the progression of NS-induced proteinuria.

Pharmacological characterization of the calcium influx pathways involved in nitric oxide production by endothelial cells / Caracterização farmacológica das vias de influxo de cálcio envolvidas na produção de óxido nítrico por células endoteliais

ABSTRACT Objective: To characterize the calcium influx pathways implicated in the sustained elevation of endothelial intracellular calcium concentration, required for the synthesis and release of relaxing factors. Methods: We evaluated the effect of the newly synthesized pyrazole derivatives, described as selective inhibitors for ORAI (BTP2/Pyr2 and Pyr6) and TRPC3 (Pyr3 and Pyr10) channels, upon endothelium- and extracellular calcium-dependent relaxations stimulated by acetylcholine and thapsigargin, in pre-constricted rat thoracic aortic rings. Results: Acetylcholine and thapsigargin responses were completely reverted by Pyr2 and Pyr6 (1 to 3μM). Pyr3 (0.3 to 3μM) caused a rapid reversal of acetylcholine (6.2±0.08mg.s−1) and thapsigargin (3.9±0.25mg.s−1) relaxations, whereas the more selective TRPC3 blocker Pyr10 (1 to 3μM) had no effect. The recently described TRPC4/5 selective blocker, ML204 (1 to 3μM), reverted completely acetylcholine relaxations, but minimally thapsigargin induced ones. Noteworthy, relaxations elicited by GSK1016790A (TRPV4 agonist) were unaffected by pyrazole compounds or ML204. After Pyr2 and Pyr6 pre-incubation, acetylcholine and thapsigargin evoked transient relaxations similar in magnitude and kinetics to those observed in the absence of extracellular calcium. Sodium nitroprusside relaxations as well as phenylephrine-induced contractions (denuded aorta) were not affected by any of pyrazole compounds (1 to 3μM). Conclusion: These observations revealed a previously unrecognized complexity in rat aorta endothelial calcium influx pathways, which result in production and release of nitric oxide. Pharmacologically distinguishable pathways mediate acetylcholine (ORAI/TRPC other than TRPC3/TRPC4 calcium-permeable channels) and thapsigargin (TRPC4 not required) induced calcium influx.

RESUMO Objetivo: Caracterizar as vias do influxo de cálcio envolvidas no aumento sustentado da concentração intracelular de cálcio na célula endotelial, essencial para a síntese e a liberação de fatores relaxantes. Métodos: Analisamos o efeito de derivados pirazólicos sintetizados recentemente, descritos como inibidores seletivos para canais ORAI (BTP2/Pyr2 e Pyr6) e TRPC3 (Pyr3 e Pyr10), nos relaxamentos dependentes de endotélio e cálcio extracelular, produzidos por acetilcolina e tapsigargina, em anéis pré-contraídos da aorta torácica de rato. Resultados: As respostas de acetilcolina e tapsigargina foram completamente revertidas por Pyr2 e Pyr6 (1 a 3μM). Pyr3 (0,3 a 3μM) produziu reversão rápida dos relaxamentos de acetilcolina (6,2±0,08mg.s−1) e tapsigargina (3,9±0,25mg.s−1), enquanto o bloqueador mais seletivo para TRPC3, Pyr10 (1 a 3μM), não apresentou efeito. ML204 (1 a 3μM), bloqueador seletivo de TRPC4, descrito há pouco tempo, reverteu os relaxamentos induzidos por acetilcolina de forma completa, mas afetou minimamente aqueles produzidos por tapsigargina. Os derivados pirazólicos ou ML204 não afetaram os relaxamentos estimulados com GSK1016790A (TRPV4-agonista). Ainda, após pré-incubação com Pyr2 e Pyr6, acetilcolina e tapsigargina provocaram relaxamentos transitórios semelhantes em magnitude e cinética àqueles observados na ausência de cálcio extracelular. Os relaxamentos do nitroprussiato de sódio e as contrações induzidas pela fenilefrina (aorta sem endotélio) não foram afetados pelos compostos pirazólicos (1 a 3μM). Conclusão: Essas observações revelaram uma complexidade desconhecida das vias de influxo de cálcio no endotélio da aorta de rato, que resultam na produção e na liberação de óxido nítrico. Vias distinguíveis farmacologicamente medeiam o influxo estimulado por acetilcolina (ORAI TRPC, diferentes de TRPC3 TRPC4) e tapsigargina (TRPC4 não requerido).

Effects of astragaloside on TRPC6 expression on mouse podocyte induced by TGF-β1 / 中国免疫学杂志

Objective:To explore the possible mechanism of astragaloside involved in the mouse podocytes injury induced by TGF-β1 in vitro.Methods:Mouse podocytes were cultured in vitro and then all cell were divided into 5 groups:normal control group , TGF-β1 treatment group ,TGF-β1 treatment +astragaloside low dose group ,TGF-β1 treatment +astragaloside middle dose group and TGF-β1 treatment +astragaloside high dose group.The proliferation rate of each group was investigated by MTT assay ,the expression of TRPC6 protein and mRNA were measured by Western blot and RT-PCR respectively after 48 hours.Results:TGF-β1 can significantly inhibit the proliferation of podocytes ( P<0.05) ,fusions of foot processes or even effaced of podocytes were observed .TGF-β1 could also increase the expression of TRPC6.Astragaloside could reduce the inhibition of TGF-β1 to the proliferain of podocytes significantly ,make the cell shape tend to be normal,and reduce the expression of TRPC6 mRNA and protein with dose-effect relation.Conclusion:TRPC6 play an impor-tant role in the TGF-β1 induecd podocytes injury .Astragaloside can alleviate podocytes injury by reduce the expression of TRPC 6.

Expressions of transient receptor potential cation channel 6 and integrin-linked kinase in glomerular of proteinuric kidney diseases / 中华肾脏病杂志

Objective To observe the expressions and distribution of transient receptor potential cation channel 6 (TRPC6) and integrin-linked kinase (ILK) in the glomeruli of renal biopsytissue of patients with proteinuric kidney diseases,and to investigate the effect of TRPC6 over-expression on ILK in vitro.Methods The archival histological specimens of patients admitted to Tangdu hospital from 2012 to 2013,with 24-hour urinary protein over 1 g,were collected.The expressions and distribution of TRPC6 and ILK in the glomeruli of renal biopsy tissue were observed by immunohistochemistry.MPC5 podocytes were cultured in vitro and they were stimulated with 10-7 mol/L ADR for 12,24 and 36 h.The pcDNA3.1(+)-TRPC6 plasmid and pcDNA3.1(+) were transfected into MPC5 podocytes by liposome 2000 reagent to establish the TRPC6 overexpression group and the negative control group respectively.Western blotting was used to detect the expressions of TRPC6 and ILK protein.Results There were 14 cases of membranous nephropathy,13 cases of focal segmental glomerulosclerosis (FSGS),15 cases of membranoproliferative glomerulonephritis,12 cases of mesangial proliferative glomerulonephritis,10 cases of hyperplastic sclerosis nephritis,15 cases of IgA nephropathy,13 cases of purpura nephritis,15 cases of lupus nephritis,13 cases of hypertensive renal injury,14 cases of diabetic nephropathy and 9 cases of normal renal tissue included.In glomerulus,TRPC6 was expressed mainly in podocytes,and the expressions of TRPC6 in these renal tissues were higher than that in normal renal tissues (all P ＜ 0.05),except for hypertensive nephropathy.ILK was expressed in podocytes and the mesangial areas.The expressions of ILK in FSGS,lupus nephritis and diabetic nephropathy were higher than that in normal kidney tissue (all P ＜ 0.05),while the other renal tissues was high but showed no statistical difference with normal kidney tissue (all P ＞ 0.05).The expressions of TRPC6 and ILK were positively correlated in renal tissues of FSGS and diabetic nephropathy (r=0.906,P ＜ 0.001;r=0.783,P=0.001 respectively).The expressions of TRPC6 and ILK protein in 24 and 36 h stimulating with ADR were significantly higher than that in the control group (all P ＜ 0.05).The expression of ILK in the TRPC6 overexpression group was significantly higher than that in the normal control group (P ＜ 0.05).Conclusions The expressions of TRPC6 and ILK increase in the glomeruli of patients with kidney diseases with proteinuria being the main manifestation,especially in FSGS and diabetic nephropathy.The up-regulation of TRPC6 can increase the expression of ILK protein,which may be involved in podocyte injury.

Pathological function of transient receptor potential canonical 6 channel in key central nervous system diseases:its prospects as drug targets / 中国药理学与毒理学杂志

Transient receptor potential canonical 6 (TRPC6) is a non-selective cation channel, which is involved in various physiological processes, including neuronal axonal growth cone guidance, promotion of dendritic growth and excitatory synaptic formation.Recent studies have shown that TRPC6 participates in many pathological process of central nervous system (CNS) diseases. Therefore, this review focuses on physiological roles of TRPC6,and its pathological roles in CNS,i.e.stroke,Alzheimer disease and epilepsy. We go on to discuss the research development of TRPC6 as drug targets.Finally,we overview and discuss the problems to be solved in further research, and the prospect of TRPC6 as a promising target for drug development.

Up-regulation of TRPC3 in the Cortex of Rats with Kainic Acid-induced Seizures / 华中科技大学学报(医学版)

Objective To observe the expression change of TRPC3 in cortex of rats with Kainic acid(KA)-induced sei-zures,and to explore the role of TRPC3 in epileptogenesis.Methods Fifty-four adult Sprague Dawley(SD)rats were randomly divided into two groups(18 for control group,36 for epilepsy group).The behavior of rats was observed and recorded.The epi-lepsy group was treated with KA(2 μg/kg,about 7 μL,lateral intracerebroventricular injection),and control group was treated with isotonic Nachloride(equivalent volume with KA,lateral intracerebroventricular injection).For epilepsy group,samples were taken 48 and 72 h after seizure burst.For control group,samples were taken 48 h after isotonic Nachloride injection.The mRNA level of TRPC3 in cortex was detected and recorded by RT-PCR,and the protein level of TRPC3 in cortex was measured by Western blotting,and immunohistochemistry was also used to display the TRPC3 expression in cortex.Results The control group showed no seizure activity,and the epilepsy group showed classical seizure activity(Ⅳ-Ⅴ level)about 5 min after injection and last for several hours.The mRNA and protein levels of TRPC3 in epilepsy group were both higher than those in control group with obvious distinction(P< 0.05).Conclusion The TRPC3 level increases in cortex of rats with KA-induced sei-zures.These results point out that TRPC3 is possibly involved in epilepsy etiopathogenesis and development.

Calcium permeability of transient receptor potential canonical (TRPC) 4 channels measured by TRPC4-GCaMP6s

Conflicting evidence has been obtained regarding whether transient receptor potential cation channels (TRPC) are store-operated channels (SOCs) or receptor-operated channels (ROCs). Moreover, the Ca/Na permeability ratio differs depending on whether the current-voltage (I-V) curve has a doubly rectifying shape or inward rectifying shape. To investigate the calcium permeability of TRPC4 channels, we attached GCaMP6s to TRPC4 and simultaneously measured the current and calcium signals. A TRPC4 specific activator, (–)-englerin A, induced both current and calcium fluorescence with the similar time course. Muscarinic receptor stimulator, carbachol, also induced both current and calcium fluorescence with the similar time course. By forming heteromers with TRPC4, TRPC1 significantly reduced the inward current with outward rectifying I-V curve, which also caused the decrease of calcium fluorescence intensity. These results suggest that GCaMP6s attached to TRPC4 can detect slight calcium changes near TRPC4 channels. Consequently, TRPC4-GCaMP6s can be a useful tool for testing the calcium permeability of TRPC4 channels.

Effect of TRPC6 knock-out on the mouse neuroinflammation induced by MPTP / 中国比较医学杂志

Objective To measure the level of microglia TRPC6 in mouse MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced neuroinflammation model and investigate its role in cytokine production and dopaminergic neuron damages. Methods Microglia were sorted by magnetic beads labeled with CD11b antibody and the level of TRPC6 in MPTP-induced neuroinflammation models was measured by western blotting. The proliferation of microglia and damages of dopaminergic neurons induced by MPTP were analyzed by immunofluorescence in CD11b-TRPC6 -/ - mice. Meanwhile, the expression of cryαB and cytokines in microglia was measured by western blotting and real-time quantitative PCR, respectively. Results The level of microglia TRPC6 in MPTP-induced neuroinflammation model was up-regulated. The expression of cryαB was increased and the cytokine level was down-regulated in the microglia in MPTP-injected CD11b-TRPC6 -/ - mice. Moreover, the dopaminergic neuron survival was improved in the MPTP-induced neuroinflammation model after TRPC6 knock-out in the microglia. Conclusions The expression of TRPC6 in microglia is up-regulated after MPTP injection, while in CD11b-TRPC6 -/ - mice the MPTP-induced cytokine expression is reduced, contributing to the improvement of dopaminergic neuron survival.

Natural modulators of transient receptor potential channels / 药学学报

Transient receptor potential (TRP) channels are non-selective and cation-permeable channels in the cell membrane, widely distributed in tissues and organs of human body. As biosensors, TRP channels can regulate the functions of vision, hearing, taste, pain, and touch, etc. So far, more than 100 different kinds of natural modulators targeting TRP channels have been identified from 70 species of plants or animals. In this review article, we attempt to summarize the effect of known natural active compounds on TRP channels with focuses on their sources, structures, action features and mechanisms. Hopefully this review can provide some useful information that can facilitate discovery of more specific natural modulators, and development of innovative therapeutic drugs targeting TRP channels.

Huangqi Danshen decoction attenuates isoproterenol-induced myocardial remodeling via STIM1, TRPC1, CaN and NFATc3 pathways in rats / 中国中药杂志

To investigate the inhibitory effect of Huangqi Danshen decoction (HDD) on isoproterenol (ISO)-induced myocardial remodeling and explore its effect on STIM1, TRPC1, CaN and NFATc3 expressions. ISO (2.5 mg•kg⁻¹•d⁻¹×14 d) was given by subcutaneous injection to establish myocardial remodeling models in rats, and then were randomly divided into control group, ISO model group, HDD5 group (HDD 5 g•kg⁻¹•d⁻¹+ISO), and HDD10 group (HDD 10 g•kg⁻¹•d⁻¹+ISO). After intervention for 4 weeks, the heart mass index (HW/BW) and the left ventricular mass index (LVW/BW) were calculated; the structure of myocardium was observed by echocardiography; the pathological changes of myocardium were observed by HE staining; levels of BNP, CaN and CaM kinases II in serum were detected by ELISA, and the protein expression levels of STIM1, TRPC1, p-CaN, p-NFATc3, and NFATc3 in left ventricular tissues were detected by Western blot. The results showed that the HW/BW and LVW/BW in ISO group were greater than those in HDD5 group and HDD10 group (P<0.05); Echocardiography showed that HDD inhibited ISO-induced increase in LVEDD and LVESD; ELISA results showed that HDD could significantly inhibit the increase of BNP, CaN and CaM kinases II levels in serum of rats with ISO-induced myocardial remodeling (P<0.01). Western blot results showed that STIM1, TRPC1, p-CaN, p-NFATc3 and NFATc3 expression levels were increased in the myocardial tissues of ISO group rats, and after HDD administration, the above expression levels were decreased in group ISO, HDD for myocardial tissue after administration of STIM1, TRPC1, p-CaN, p-NFATc3 and NFATc3 expression decreased (P<0.05). Our findings indicated that HDD can attenuate the myocardial remodeling induced by ISO, and its mechanism may be related to down-regulating the expression levels of STIM1, TRPC1, CaM kinases II, p-CaN/CaN and p-NFATc3/NFATc3.

Orai1 and Orai3 in Combination with Stim1 Mediate the Majority of Store-operated Calcium Entry in Astrocytes

Astrocytes are non-excitable cells in the brain and their activity largely depends on the intracellular calcium (Ca²⁺) level. Therefore, maintaining the intracellular Ca²⁺ homeostasis is critical for proper functioning of astrocytes. One of the key regulatory mechanisms of Ca²⁺ homeostasis in astrocytes is the store-operated Ca²⁺ entry (SOCE). This process is mediated by a combination of the Ca²⁺-store-depletion-sensor, Stim, and the store-operated Ca²⁺-channels, Orai and TrpC families. Despite the existence of all those families in astrocytes, previous studies have provided conflicting results on the molecular identification of astrocytic SOCE. Here, using the shRNA-based gene-silencing approach and Ca²⁺-imaging from cultured mouse astrocytes, we report that Stim1 in combination with Orai1 and Orai3 contribute to the major portion of astrocytic SOCE. Gene-silencing of Stim1 showed a 79.2% reduction of SOCE, indicating that Stim1 is the major Ca²⁺-store-depletion-sensor. Further gene-silencing showed that Orai1, Orai2, Orai3, and TrpC1 contribute to SOCE by 35.7%, 20.3%, 26.8% and 12.2%, respectively. Simultaneous gene-silencing of all three Orai subtypes exhibited a 67.6% reduction of SOCE. Based on the detailed population analysis, we predict that Orai1 and Orai3 are expressed in astrocytes with a large SOCE, whereas TrpC1 is exclusively expressed in astrocytes with a small SOCE. This analytical approach allows us to identify the store operated channel (SOC) subtype in each cell by the degree of SOCE. Our results propose that Stim1 in combination with Orai1 and Orai3 are the major molecular components of astrocytic SOCE under various physiological and pathological conditions.

Effect of atorvastatin on TRPC5 expression in atherosclerosis of apoli-poprotein E-knockout mice / 中国病理生理杂志

AIM: To observe the changes of transient receptor potential channel 5 (TRPC5) in vascular smooth muscle cells ( VSMCs) of apolipoprotein E-knockout ( ApoE-/-) mice and the effect of atorvastatin interference, and to investigate the mechanism of atorvastatin therapy.METHODS:Male ApoE-/-mice at 6 weeks of age were used to establish the atherosclerosis model by feeding with hyperlipidic diet.The mice were randomly divided into model group and atorvastatin group.The mice in atorvastatin group were lavaged with atorvastatin at 20 mg· kg-1 · d-1 , while the mice in model group received normal saline.The healthy C57BL/6J mice with the same age and the same genetic background, feeding with ordinary food, served as control group.At the time points of 14 and 24 weeks, the mice were sacrificed.The serum was collected for detecting the lipid levels.The aortic roots of the heart were taken to make paraffin sections with HE staining for measuring and comparing the relative atherosclerotic plaque area in each section.The expression of TRPC5 in VSMCs was examined with immunohistochemical staining.The mRNA levels of TRPC5 in the serum and the thoracoabdom-inal aorta were measured by real-time PCR.RESULTS: Compared with model group, blood lipids in atorvastatin group were significantly decreased, and the formation of plaque under aorta intima also decreased.The protein expression of TR-PC5 in atorvastatin group decreased significantly compared with model group.Compared with 20-week model group, TRPC5 in 30-week model group showed increasing tendency, but has no statistical significance.Compared with 20-week atorvasta-tin group, TRPC5 of 30-week atorvastatin group declined.CONCLUSION: Atorvastatin suppresses TRPC5 expression, thus attenuating atherosclerotic development in ApoE-/-mice.