Cl(-) channel has been identified in heart over more than a decade. It is now known that Cl(-) channel is a super-family. The potentially important roles of cardiac Cl(-) channels have been emerging. Cardiac Cl(-) channels may play multifunctional roles in both physiological and pathophysiological conditions. Since the existence and distribution of cardiac Cl(-) channels vary with species and cardiac tissues, and blockade of Cl (-) channel with putative Cl(-) channel blockers or Cl(-) substitution has profound influence on cardiac electrical properties, it appears that the main role of cardiac Cl(-) channels may be to modulate cation channels or provide an ionic environment suitable for the activities of cation channels. So, to investigate the relationship between Cl(-) channels and cation channels may be of physiological and pathophysiological significance.
Animals ; Calcium Channels ; physiology ; Cations ; metabolism ; Chloride Channels ; physiology ; Heart ; physiology ; Humans ; Potassium Channels ; physiology ; Sodium Channels ; physiology ; TRPM Cation Channels ; physiology

Transient receptor potential (TRP) channel is a superfamily of cation channels located on the cell membrane. TRP channels are classified into seven subfamilies based on the amino acid sequence homology,and transient receptor potential melastatin 2(TRPM2) is the second member of the TRPM subfamily. More evidences have revealed the important roles of TRPM2 in physiological and pathological events such as release of insulin from pancreatic Β-cells,inflammatory cytokines production from cells,and oxidative stress-induced cell death. As a cellular sensor for oxidative stress channel,TRPM2 is activated by a variety of factors. TRPM2 is a potential therapeutic target for oxidative stress-related diseases.
Cell Death ; Cytokines ; Humans ; Insulin ; Oxidative Stress ; TRPM Cation Channels ; physiology

Transient receptor potential (TRP) superfamily is a superfamily of cation channels that can be divided into seven subfamilies. TRPM2 is the second member of the TRPM subfamily, which includes eight members, namely TRPM1-8. TRPM2 is widely expressed in excitable and non-excitable cells, where it forms a Ca(2+)-permeable cation channel and performs diverse cellular functions. TRPM2 channels are activated by ADP-ribose (ADPR), Ca(2+), H2O2 and other reactive oxygen species (ROS). It is established that TRPM2 serves as a cellular sensor for oxidative stress, mediating oxidative stress-induced [Ca(2+)]i increase and contributing to pathological processes in many cell types. Accumulating evidence has indicated that TRPM2 is a potential therapeutic target for oxidative stress-related diseases. This review will highlight recent progress in this field.
Adenosine Diphosphate Ribose ; metabolism ; Calcium ; physiology ; Calcium Channels ; physiology ; Humans ; Hydrogen Peroxide ; metabolism ; Oxidative Stress ; Reactive Oxygen Species ; metabolism ; TRPM Cation Channels ; physiology

As a crucial signaling molecule, calcium plays a critical role in many physiological and pathological processes by regulating ion channel activity. Recently, one study resolved the structure of the transient receptor potential melastatin 2 (TRPM2) channel from Nematostella vectensis (nvTRPM2). This identified a calcium-binding site in the S2-S3 loop, while its effect on channel gating remains unclear. Here, we investigated the role of this calcium-binding site in both nvTRPM2 and human TRPM2 (hTRPM2) by mutagenesis and patch-clamp recording. Unlike hTRPM2, nvTRPM2 cannot be activated by calcium alone. Moreover, the inactivation rate of nvTRPM2 was decreased as intracellular calcium concentration was increased. In addition, our results showed that the four key residues in the calcium-binding site of S2-S3 loop have similar effects on the gating processes of nvTRPM2 and hTRPM2. Among them, the mutations at negatively charged residues (glutamate and aspartate) substantially decreased the currents of nvTRPM2 and hTRPM2. This suggests that these sites are essential for calcium-dependent channel gating. For the charge-neutralizing residues (glutamine and asparagine) in the calcium-binding site, our data showed that glutamine mutating to alanine or glutamate did not affect the channel activity, but glutamine mutating to lysine caused loss of function. Asparagine mutating to aspartate still remained functional, while asparagine mutating to alanine or lysine led to little channel activity. These results suggest that the side chain of glutamine has a less contribution to channel gating than does asparagine. However, our data indicated that both glutamine mutating to alanine or glutamate and asparagine mutating to aspartate accelerated the channel inactivation rate, suggesting that the calcium-binding site in the S2-S3 loop is important for calcium-dependent channel inactivation. Taken together, our results uncovered the effect of four key residues in the S2-S3 loop of TRPM2 on the TRPM2 gating process.
Animals ; Asparagine/physiology* ; Binding Sites ; Calcium/metabolism* ; Glutamine/physiology* ; HEK293 Cells ; Humans ; Ion Channel Gating/physiology* ; Sea Anemones ; TRPM Cation Channels/physiology*

OBJECTIVETo investigate the role of transient receptor potential melastatin 8 (TRPM8) channels in migraine mechanism in rats by measuring the changes in expression of TRPM8 in the trigeminal nerve of rats with migraine.

METHODSTwenty male Sprague-Dawley rats were randomly and equally divided into a blank control group and a model group. Nitroglycerin (10 mg/kg) was injected subcutaneously in the back of the neck once a week for 5 weeks, to prepared a rat model of migraine without aura. Normal saline was injected subcutaneously instead of nitroglycerin in the control group. At 4 hours after the final injection, behavior scoring of all rats was performed, and then the trigeminal nerve ganglions of rats in both groups were collected for measurement of expression of N-methyl-D-aspartate receptor (NMDAR), protein kinase A (PKA), and TRPM8 using immunohistochemical staining, immunofluorescence, and Western blot, respectively.

RESULTSThe behavior score in each week during the rat model preparing was significantly higher in the model group than in the control group (P<0.05). The expression of NMDAR, PKA, and TRPM8 in the model group was significantly higher than in the control group (P<0.01). Both the behavior score and the expression of NMDAR were positively correlated with the expression of TRPM8 (r=0.822 and 0.794 respectively; P<0.01).

CONCLUSIONSTRPM8 may be involved in migraine mechanism probably by activation of the NMDAR pathway.

Animals ; Cyclic AMP-Dependent Protein Kinases ; analysis ; Male ; Migraine Disorders ; etiology ; Rats ; Rats, Sprague-Dawley ; Receptors, N-Methyl-D-Aspartate ; analysis ; physiology ; TRPM Cation Channels ; physiology

To investigate the association between single nucleotide polymorphism (SNP) in the 11th exon of transient receptor potential melastatin 2 (TRPM2) gene with the susceptibility and outcome of sepsis.A total of 119 septic patients and 112 normal subjects were enrolled from the First Affiliated Hospital, Zhejiang University School of Medicine. Among 119 septic patients, 62 died (fatal group) and 57 survived (survival group) within 28 days of disease onset. The genotypes of these individuals were detected using TaqMan allelic discrimination assays, and its correlations with susceptibility and outcome of sepsis were analyzed.There was no significant difference in genotype frequencies and allelic frequencies of TRPM2 SNP rs1556314 between septic patients and the controls (all>0.05). And no significant difference in genotype frequencies and allelic frequencies of TRPM2 SNP rs1556314 was observed between the survivors and fatal cases of septic patients (all>0.05).The TRPM2 SNP rs1556314 does not have significant association with sepsis, but this result need to be confirmed by large scale studies.
Exons ; genetics ; physiology ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; genetics ; Genotype ; Humans ; Male ; Polymorphism, Single Nucleotide ; genetics ; physiology ; Sepsis ; genetics ; mortality ; TRPM Cation Channels ; genetics

We investigated the effects of transient receptor potential M8 (TRPM8) channel on the proliferation and motility of androgen-independent prostate cancer PC-3 cells. After being permanently transfected with an empty vector and cDNA encoding the TRPM8 protein, cells were analysed for cell cycle distribution and motility using flow cytometry and scratch assay. Immunocytochemistry and Ca2+ imaging analysis revealed the overexpression of functional TRPM8 channel on both endoplasmic reticulum and plasma membrane of PC-3-TRPM8 cells. Cell cycle distribution and scratch assay analysis revealed that TRPM8 induced cell cycle arrest at the G0/G1 stage (P < 0.05) and facilitated the cell apoptosis induced by starvation (P < 0.05). Furthermore, TRPM8 inhibited the migration of PC-3-TRPM8 cells (P < 0.01) through the inactivation of focal-adhesion kinase. It appears that TRPM8 was not essential for the survival of PC-3 cells; however, the overexpression of TRPM8 had negative effects on the proliferation and migration of PC-3 cells. Thus, TRPM8 and its agonists may serve as important targets for the treatment of prostate cancer.
Adenocarcinoma ; genetics ; metabolism ; pathology ; Apoptosis ; Calcium ; metabolism ; Cell Cycle ; Cell Line, Tumor ; Cell Movement ; physiology ; Cell Proliferation ; Cell Transformation, Neoplastic ; Cytosol ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Epithelial Cells ; metabolism ; pathology ; Focal Adhesion Protein-Tyrosine Kinases ; antagonists & inhibitors ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Prostatic Neoplasms ; genetics ; metabolism ; pathology ; Starvation ; pathology ; TRPM Cation Channels ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism ; Transfection

Apoptosis ; Cell Cycle ; Cell Line, Tumor ; Cell Movement ; physiology ; Cell Proliferation ; Cell Transformation, Neoplastic ; DNA-Binding Proteins ; genetics ; metabolism ; Epithelial Cells ; metabolism ; pathology ; Focal Adhesion Protein-Tyrosine Kinases ; antagonists & inhibitors ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; Prostatic Neoplasms ; genetics ; metabolism ; pathology ; TRPM Cation Channels ; genetics ; metabolism ; Transcription Factors ; genetics ; metabolism

OBJECTIVE: To construct phosphorylation sites domain (PSD) mutant of myristoylated alaninerich C kinase substrate (MARCKS) and explore the role of transient receptor potential melastatin 8 cation channels (TRPM8) and MARCKS in cold-induced synthesis and exocytosis of mucin (MUC) 5AC. METHODS: Human placental cDNA was used as a template to amplify the full coding region of MARCKS cDNA by PCR. Ser159, Ser 163, Ser 167, Ser 170 in the PSD were mutated to aspartic acids by an overlap PCR method. The resultant PSD mutant cDNA and the wild-type MARCKS cDNA were each subcloned into a mammalian expression vector pcDNA3.0. Recombinant constructs were confirmed by restriction enzyme digestion analysis and DNA sequencing. In intervention experiments, cells were pretreated with the TRPM8 channel antagonist BCTC and transfected with MARCKS-PSD mutant cDNA, and thereafter cold stimulation was applied. The levels of MUC5AC were measured by immunofluorescence and ELISA to clarify the roles of TRPM8 and PSD mutant on the synthesis and secretion of MUC5AC induced by cold, respectively. RESULTS: Restriction enzyme digestion analysis and DNA sequencing revealed that the pcDNA3.0- MARCKS and pcDNA3.0-MARCKS-PSD mutants were successfully constructed. The levels of intracellular and secreted MUC5AC of cold treated group were significantly higher than those of control group (P<0.05). BCTC attenuated the cold-induced synthesis and secretion of MUC5AC when compared with cold treated group (P<0.05). Transfection of 16HBE cells with the MARCKS-PSD mutant cDNA resulted in significant inhibition of mucin secretion in response to cold, and significantly higher level of intracellular MUC5AC than that of control group (P<0.01), whereas transfection with the vector DNA or the wild-type MARCKS cDNA had no effect on the mucin synthesis and secretion in response to cold (P>0.05). CONCLUSION TRPM8 and phosphorylation of MARCKS-PSD mediates the cold-induced exocytosis of MUC5AC by airway epithelial cells.
Base Sequence ; Cell Line ; Cold Temperature ; Epithelial Cells ; cytology ; metabolism ; Exocytosis ; physiology ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Molecular Sequence Data ; Mucin 5AC ; metabolism ; Mutation ; Myristoylated Alanine-Rich C Kinase Substrate ; Phosphorylation ; TRPM Cation Channels ; metabolism ; Trachea ; cytology ; metabolism