The TRPC family consists of multiple important cationic channels in mammals that participate in a variety of physiological and pathological processes. Our previous studies have shown that transforming growth factor-β1 (TGF-β1) increases the expression of TRPC6 in podocytes, but the roles of other members of the TRPC family in podocytes require further investigation. In this study, we investigated the effect of TGF-β1 on the expression of the TRPC family and the role of the TRPC family in the changes of the intracellular Ca²⁺ concentration ([Ca²⁺]_i) in podocytes induced by TGF-β1. The model of podocyte injury was established by treatment with TGF-β1 in immortalized glomerular podocytes (MPC5) in vitro. qRT-PCR and Western blot were used to detect the effect of TGF-β1 on the mRNA and protein expression of each TRPC family member. After the expression of each TRPC family member was knocked down by a siRNA-based approach and blocked by SKF96365, respectively, free cytosolic Ca²⁺ was measured using the fluorescent Ca²⁺ indicator Fluo-3/AM, and the dynamic change of [Ca²⁺]_i in podocytes was detected by a dynamic high-speed calcium imaging system. The results showed that TGF-β1 increased the protein expression of TRPC1/3/6 in podocytes, but had no effects on the protein expression of TRPC4. The protein expression levels of TRPC5/7 were only affected by 4 ng/mL and 8 ng/mL TGF-β1, respectively. TGF-β1 increased TRPC1/3/6 mRNA levels in podocytes, however had no effects on TRPC4/5/7 mRNA. TGF-β1 significantly increased [Ca²⁺]_i in podocytes. Knockdown of TRPC1/4/5/7 in podocytes had no significant effect on the [Ca²⁺]_i induced by TGF-β1, but TRPC3/6 knockdown significantly decreased the [Ca²⁺]_i. There was no significant difference in the [Ca²⁺]_i between the TRPC6 siRNA-treated group and SKF96365-treated group, but the [Ca²⁺]_i of the TRPC3 siRNA-treated group was significantly higher than that of SKF96365-treated group. These results demonstrate that TGF-β1 increases the expression of the TRPC1/3/6 in podocytes. TGF-β1 increases [Ca²⁺]_i in podocytes, which is dependent on the TRPC3/6 expression. Our results also suggest that the effect of TRPC6 on [Ca²⁺]_i in podocytes may be greater than that of TRPC3.
Animals ; TRPC6 Cation Channel/metabolism* ; Calcium/metabolism* ; TRPC Cation Channels/metabolism* ; Podocytes/metabolism* ; Transforming Growth Factor beta1/metabolism* ; RNA, Small Interfering/metabolism* ; RNA, Messenger/metabolism* ; Mammals/metabolism*

Transient receptor potential (TRP) A1, a member of TRP channel family, is activated by noxious cold. The aims of this study were to determine if TRPA1 contributed to cold-induced contractions in the isolated rat colon preparations and explore the potential mechanisms. The colon smooth muscle layers were surgically isolated from the male Wistar rats and changes in isotonic tension of longitudinal muscle under various treatments were recorded as colonic motilities. Cold stimuli were obtained by the reperfusion with Krebs-Henseleit solution at given temperature using Constant Flow Pump. The mRNA expressions of TRPA1, TRPV1 and TRPM8 in rat colon smooth muscle layer were examined by using reverse transcription-polymerase chain reaction (RT-PCR) techniques. The results showed that the contractions induced by cold stimuli (from 37 degrees C to 12 degrees C stepwise) were inversely proportional to the temperature with a maximum contraction at 17 degrees C in both proximal and distal colons (P<0.01). RT-PCR analysis revealed the expression of TRPA1, but not TRPM8 and TRPV1, in the rat proximal and distal colon smooth muscle layers. Cold-induced colonic contractions were specially inhibited by TRPA1 blocker, ruthenium red (30 μmol/L), in the proximal and distal colon (P<0.05). The cold-induced contractions of proximal (P<0.01, P<0.05) and distal colons (both P<0.001) were almost abolished or inhibited by the pretreatments of TRPA1 agonists, Allyl isothiocyanate (AITC, 300 μmol/L) and cinnamaldehyde (CA, 1 mmol/L). Extracellular calcium removal (EGTA, 1 mmol/L), PLC blocker (U73122, 10 μmol/L) and IP(3) receptor blocker (2-aminoethoxydiphenyl borate, 2-APB, 30 μmol/L) all decreased the contractions evoked by the cooling at 17 degrees C in the proximal and distal colon (P<0.001, P<0.05, P<0.001). Atropine (1 μmol/L) had no effects on these contractions. L-type Ca(2+) channels blocker nifedipine (1 μmol/L) and neurotoxin tetrodotoxin (TTX, 2 μmol/L) decreased the contractile response in the distal colon (P<0.01, P<0.05), but not in the proximal colon. In conclusion, TRPA1 contributes to cold-induced contractions of the rat colon smooth muscle, and the mechanism of TRPA1 activation involves PLC/IP(3)/Ca(2+) pathway. L-type Ca(2+) channel and neurogenic mechanism other than muscarinic receptor might be partially involved in cold-induced contraction of the distal colon, which probably resulted in higher contraction of distal colon compared with that of proximal colon.
Animals ; Calcium Channels, L-Type ; metabolism ; Cold Temperature ; Colon ; metabolism ; physiology ; In Vitro Techniques ; Male ; Muscle Contraction ; physiology ; Muscle, Smooth ; metabolism ; physiology ; Physical Stimulation ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; TRPA1 Cation Channel ; TRPC Cation Channels ; genetics ; metabolism

OBJECTIVETo detect the expression of transient receptor potential canonical 1 (TRPC1) in a mouse model of ozone-induced lung inflammation and explore its role in lung inflammation.

METHODSIn a mouse model of lung inflammation established by ozone exposure, the expression of TRPC1 in the inflammatory lung tissues was detected by RT-PCR, Wstern blotting and immunohistochemistry.

RESULTSCompared to the control mice, the mice exposed to ozone showed significantly increased expression level of TRPC1 mRNA and protein in the inflammatory lung tissues (P<0.05). Immunohistochemistry showed increased TRPC1 protein expressions in the alveolar epithelial cells, bronchial epithelial cells, and inflammatory cells in the inflammatory lung tissues (P<0.05). The mRNA and protein expression levels of TRPC1 were positively correlated with the counts of white blood cells, macrophages, neutrophils and lymphocytes in the bronchoalveolar lavage fluid of the exposed mice (P<0.01).

CONCLUSIONTRPC1 may play a role in ozone-induced lung inflammation in mice.

Animals ; Bronchoalveolar Lavage Fluid ; Disease Models, Animal ; Gene Expression ; Inflammation ; pathology ; Lung ; metabolism ; pathology ; Mice ; Ozone ; adverse effects ; Pneumonia ; metabolism ; pathology ; RNA, Messenger ; TRPC Cation Channels ; metabolism

BACKGROUND AND OBJECTIVETransient receptor potential canonical (TRPC) proteins, a group of Ca2' permeable nonselective cation channels, are thought to constitute store-operated calcium channels (SOCC) and mediate store-operated calcium entry (SOCE) in various cell types. Members of TRPC have been found to be involved in abnormal proliferation, differentiation, and growth of cancer cells. The aim of this study is to detect the mRNA and protein expression of TRPC in non-small cell lung cancer (NSCLC).

METHODSReal-time quantitative PCRwas performed to screen the expression of TRPC mRNA in NSCLC tissue. Protein expression of TRPC was detected by Western blot.

RESULTSAmong the seven family members of TRPC so far identified (TRPC1-7), we detected the expression ofTRPC1, TRPC3, TRPC4, TRPC6 mRNA in 24 cases of NSCLC tissue; TRPC2, TRPC5 and TRPC7 mRNA were not detectable. The relative abundance of the expressed TRPC was TRPC1 approximately equal TRPC6 > TRPC3 > TRPC4. Western blot confirmed the protein expression of TRPC1, TRPC3, TRPC4 and TRPC6 in NSCLC tissue.

CONCLUSIONOut of the seven members of TRPC, we found TRPC1, TRPC3, TRPC4, TRPC6 mRNA and protein were selectively expressed in human NSCLC tissue. This study could provide a basis for future exploration of the individual role of these TRPC proteins in mediating SOCE and in the progression of lung cancer.

Adult ; Aged ; Blotting, Western ; Calcium ; metabolism ; Carcinoma, Non-Small-Cell Lung ; metabolism ; Female ; Humans ; Lung Neoplasms ; metabolism ; Male ; Middle Aged ; RNA, Messenger ; analysis ; TRPC Cation Channels ; genetics ; physiology

OBJECTIVETo study the roles of stromal interaction molecule 2 (STIM2) and transient receptor potential canonical 3 (TRPC3) in extracellular Ca(2+)-sensing receptor (CaR)-induced extracellular Ca2+ influx and the production of nitric oxide (NO) in human umbilical vein endothelial cells (HUVEC).

METHODS(1) The interaction of STIM2 and TRPC3 was determined using the immunofluorescence technique. (2) The expressions of STIM2 and TRPC3 genes were silenced in HUVEC by transfection constructed STIM2 and TRPC3 RNA interference plasmids. The interference efficiency of STIM2, TRPC3 protein and mRNA levels were determined by Western blot and real time RT-PCR, respectively. (3) The second to fifth passage of HUVEC were divided into: STIM2-002 short hairpin RNA (STIM2-002 shRNA ) + spermine + Ca2+ group and TRPC3-004 short hairpin RNA (TRPC3-004 shRNA ) + spermine + Ca2+ group; control group (spermine + Ca2+ group) and vehicle+ spermine + Ca2+ group. The four groups of cells were incubated with CaR agonist spermine, the intracellular Ca2+ concentration ([Ca2+]i) was detected using the fluorescence Ca2+ indicator Fura-2/AM, and the production of NO was determined by DAF-FM (NO fluorescent probe) of each group in HUVEC.

RESULTS(1) Immunofluorescence technique results showed that STIM2 and TRPC3 proteinswere present in the cytoplasm of HUVEC. (2) The results of transfection constructed STIM2 and TRPC3 RNA interference plasmids demonstrated that shRNA targeted to the STIM2 and TRPC3 genes decreased STIM2 and TRPC3 mRNA levels by 88.2% and 74.0%, respectively (P < 0.05), simultaneously, the STIM2 and TRPC3 protein levels were decreased by 79.9% and 71.8%, respectively (P < 0.05). (3) Compared with spermine + Ca2+ group, the [Ca2+]i and the net NO fluorescence intensity of spermine + Ca(2+) + ShSTIM2-002 group, spermine + Ca(2+) + ShTRPC3-004 group and spermine + Ca2+ Vehicle group were not changed (P > 0.05).

CONCLUSIONSTIM2 and TRPC3 do not participate in CaR-mediated Ca2+ influx and NO production individually.

Calcium ; metabolism ; Cell Adhesion Molecules ; physiology ; Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; physiology ; Humans ; Nitric Oxide ; metabolism ; Stromal Interaction Molecule 2 ; TRPC Cation Channels ; physiology

Pulmonary arterial hypertension is associated with profound vascular remodeling and alterations in Ca2+ homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Recent studies show that canonical transient receptor potential channel 6 (TRPC6) genes, which encode receptor-operated cation channels (ROCC) in PASMCs, play an important role in Ca2+ regulation and cell proliferation. The aim of the present study was to investigate the role of TRPC6 in monocrotaline (MCT)-induced pulmonary artery hypertension. Sprague-Dawley rats were randomly divided into normal control group and MCT group. In MCT group, pulmonary arterial hypertension was induced by a single intraperitoneal injection of MCT at a dose of 60 mg/kg. After 3 weeks, the right ventricular systolic pressure (RVSP) and the right ventricular mass index (RVMI) were measured. The lung sections were stained by HE and observed under light microscope. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot were performed to detect the expression of TRPC6 in rat pulmonary arteries. The 1-oleoyl-2-acetyl-sn-glycerol (OAG)-induced contractile tension of pulmonary arteries were measured by vascular ring tension analysis and the intracellular Ca2+ concentration ([Ca2+](i))of PASMCs was monitored using Fluo3-AM assay. The results showed that RVSP and RVMI markedly elevated in MCT group (P<0.01) in comparison to CON group. The thickness of pulmonary vascular smooth muscles was increased and the inner diameter of pulmonary arteries was diminished in MCT group. Though there was no significant difference in the levels of mRNA and protein of TRPC6 between CON and MCT groups, the application of OAG, which can directly activate ROCC, induced greater contraction tension of pulmonary arteries (P<0.01) and more Ca2+ entries in PASMCs (P<0.05) in MCT group compared to those in control group. These results indicate that MCT induces pulmonary artery hypertension and thus remodeling of the right ventricle and pulmonary arteries in rats. The expression of mRNA and protein of TRPC6 is not potentiated by MCT, but the TRPC6/ROCC-mediated Ca2+ entry in PASMCs and vascular tone of pulmonary arteries are significantly increased with MCT treatment.
Animals ; Calcium ; metabolism ; Hypertension, Pulmonary ; chemically induced ; metabolism ; physiopathology ; Male ; Monocrotaline ; pharmacology ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Myocytes, Smooth Muscle ; cytology ; metabolism ; Pulmonary Artery ; cytology ; metabolism ; physiopathology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; TRPC Cation Channels ; genetics ; metabolism

OBJECTIVETo explore the role of transient receptor potential canonical 1 (TRPC1) in airway remodeling and the effect of budesonide intervention on its expression in the lungs of guinea pigs with ovalbumin-induced asthma.

METHODSFifty male guinea pigs were randomized into 5 equal groups, including a blank control group, ovalbumin group, ovalbumin+TRPC1 siRNA group, ovalbumin+luciferase siRNA group, and ovalbumin+budesonide group. After corresponding treatments, bronchoalveolar lavage was collected from the guinea pigs for eosinophils analysis and detection of IL-5 and IL-13 levels using ELISA. The lung tissues were stained with HE and Masson's trichrome to observe the bronchial wall thickness, smooth muscle hypertrophy, subepithelial collagen deposition, and lung inflammations. Immunohistochemistry and real-time quantitative PCR were performed to detect TRPC1 protein and mRNA expressions in the lungs, respectively.

RESULTSThe guinea pig models of ovalbumin-induced asthma showed significantly increased thickness of the bronchial wall, smooth muscle hypertrophy, collagen deposition and inflammatory cell infiltration, but these pathologies were obviously alleviated by treatment with TRPC1 siRNA or budesonide (P/0.05). Immunohistochemstry showed that TRPC1 protein was distributed mainly on the cell membrane and in the nuclei of the basal cells or columnar epithelial cells.

CONCLUSIONThe up-regulated expression of TRPC1 ion channel is closely associated with the occurrence and progression of airway remodeling and chronic airway inflammation in asthma. Budesonide can partially suppress airway remodeling and inflammation by regulating the expression of TRPC1.

Airway Remodeling ; Animals ; Asthma ; drug therapy ; metabolism ; Bronchi ; pathology ; Budesonide ; pharmacology ; Disease Models, Animal ; Guinea Pigs ; Inflammation ; metabolism ; Interleukin-13 ; metabolism ; Interleukin-5 ; metabolism ; Leukocyte Count ; Lung ; drug effects ; metabolism ; Male ; Ovalbumin ; TRPC Cation Channels ; metabolism

During membrane depolarization associated with skeletal excitation-contraction (EC) coupling, dihydropyridine receptor [DHPR, a L-type Ca2+ channel in the transverse (t)-tubule membrane] undergoes conformational changes that are transmitted to ryanodine receptor 1 [RyR1, an internal Ca2+-release channel in the sarcoplasmic reticulum (SR) membrane] causing Ca2+ release from the SR. Canonical-type transient receptor potential cation channel 3 (TRPC3), an extracellular Ca2+-entry channel in the t-tubule and plasma membrane, is required for full-gain of skeletal EC coupling. To examine additional role(s) for TRPC3 in skeletal muscle other than mediation of EC coupling, in the present study, we created a stable myoblast line with reduced TRPC3 expression and without alpha1SDHPR (MDG/TRPC3 KD myoblast) by knock-down of TRPC3 in alpha1SDHPR-null muscular dysgenic (MDG) myoblasts using retrovirus-delivered small interference RNAs in order to eliminate any DHPR-associated EC coupling-related events. Unlike wild-type or alpha1SDHPR-null MDG myoblasts, MDG/TRPC3 KD myoblasts exhibited dramatic changes in cellular morphology (e.g., unusual expansion of both cell volume and the plasma membrane, and multi-nuclei) and failed to differentiate into myotubes possibly due to increased Ca2+ content in the SR. These results suggest that TRPC3 plays an important role in the maintenance of skeletal muscle myoblasts and myotubes.
Animals ; Calcium/metabolism ; Calcium Channels/metabolism ; Calcium Channels, L-Type/genetics/metabolism ; Cations/metabolism ; *Cell Differentiation ; *Cell Proliferation ; Cells, Cultured ; Excitation Contraction Coupling ; Gene Knockdown Techniques ; Membrane Potentials ; Mice ; Muscle Fibers, Skeletal/*metabolism ; Muscle Proteins/metabolism ; Myoblasts, Skeletal/*metabolism ; Ryanodine Receptor Calcium Release Channel/metabolism ; Sarcoplasmic Reticulum/*physiology ; Synaptophysin/metabolism ; TRPC Cation Channels/genetics/*metabolism ; Transient Receptor Potential Channels/metabolism

The present study was to investigate the role of TRPC6 in pulmonary artery smooth muscle cells (PASMCs) proliferation and apoptosis under hypoxia and hypercapnia. PASMCs were isolated from chloral hydrate-anesthetized male Sprague-Dawley (SD) rats. Cellular purity was assessed by immunofluorescence staining for smooth muscle α-actin under fluorescence microscopy. Passage 4-6 PASMCs were starved for 24 h in serum-free DMEM and divided into 5 groups randomly: normoxia, hypoxia and hypercapnia, DMSO, TRPC6 inhibitor SKF-96365 and TRPC6 activator OAG groups. The normoxic group was incubated under normoxia (5% CO, 21% O, 37 °C) for 24 h, and the others were incubated with corresponding drugs under hypoxic and hypercapnic (6% CO, 5% O, 37 °C) atmosphere for 24 h. TRPC6 mRNA was detected by reverse transcription-PCR. TRPC6 protein was detected by Western blotting. The proliferation of PASMCs was performed by CCK-8 kit. Apoptosis of the PASMCs was detected using TUNEL assay. The [Ca]in the PASMCs was measured using Fura 2-AM fluorescence. The results showed that the expressions of TRPC6 mRNA and protein, and [Ca]were upregulated under hypoxic and hypercapnic conditions. Hypoxia and hypercapnia promoted cellular proliferation and inhibited apoptosis in the PASMCs. OAG enhanced the above-mentioned effects of hypoxia and hypercapnia, whereas SKF-96365 reversed these effects. These results suggest that TRPC6 may play a role in PASMCs proliferation and apoptosis under hypoxia and hypercapnia by regulating [Ca].
Actins ; Animals ; Apoptosis ; Calcium ; metabolism ; Cell Hypoxia ; Cell Proliferation ; Cells, Cultured ; Hypercapnia ; physiopathology ; Imidazoles ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; metabolism ; Pulmonary Artery ; cytology ; Rats ; Rats, Sprague-Dawley ; TRPC Cation Channels ; metabolism

This study was aimed to construct eukaryotic expression vectors carrying the small hairpin RNA (shRNA) targeting TRPC6 gene and investigate the effect of TRPC6 knockdown on puromucin aminonucleoside (PAN)-induced podocyte injury. Two DNA sequences containing the small hairpin structure targeting TRPC6 were designed, synthesized and then inserted into the green fluorescence protein (GFP)-contained plasmids (pGC) to establish the plasmids pGCsi-TRPC6A and pGCsi-TRPC6B. Plasmids expressing scrambled shRNA were used as negative control and named pGCsi-NC. These plasmids were transfected into a conditionally immortalized murine podocyte cell line by using liposome. Flow cytometry was used to examine the transfection efficiency. TRPC6 mRNA and protein expression levels were detected by RT-PCR and Western blotting. Cultured podocytes were divided into four groups: control group, PAN treatment group, PAN+TRPC6 shRNA transfected group and PAN+scrambled shRNA transfected group. The paracelluar permeability to BSA was evaluated by Millicell-PCF Inserts and cell viability was measured by the trypan blue assay. Immunofluorescent assay was used to observe the distribution of α-actinin-4 and α-tubulin. The results showed that the transfection efficiency of the shRNA expression vector was about 45%. Expression levels of TRPC6 mRNA and protein were downregulated after transfection with pGCsi-TRPC6A and pGCsi-TRPC6B. Knocking down TRPC6 gene could effectively reverse the PAN-induced increase in the paracelluar permeability to BSA. The distribution of α-actinin-4 and α-tubulin was disrupted after treatment with PAN, which was reversed by knocking down TRPC6 gene. It was concluded that knocking down TRPC6 gene could effectively prevent podocytes from the permeability increase induced by PAN, which may be related to the regulation of podocyte cytoskeleton.
Animals ; Cell Membrane Permeability ; drug effects ; physiology ; Cell Survival ; drug effects ; physiology ; Cells, Cultured ; Gene Knockdown Techniques ; Mice ; Mice, Knockout ; Podocytes ; drug effects ; physiology ; Puromycin Aminonucleoside ; pharmacology ; TRPC Cation Channels ; genetics ; metabolism