OBJECTIVETo investigate the effect of KN93, a calmodulin-dependent protein kinase II (CaMK II) inhibitor, on SH-SY5Y cell injury induced by bupivacaine hydrochloride.

METHODSSH-SY5Y cells exposed for 24 h to 1 mmol/L KN93, 1 mmol/L bupivacaine hydrochloride, or both were examined for morphological changes and Cav3.1 protein expressions using Western blotting. The vitality and apoptosis rate of the cells at different time points during the exposures were assessed with MTT assay and flow cytometry, respectively.

RESULTSBupivacaine hydrochloride exposure caused obvious cell morphologial changes, reduced cell viability, increased cell apoptosis, and enhanced Cav3.1 protein expression. All these changes were partly reversed by treatment of the cells with 1 mmol/L KN93.

CONCLUSIONSCaMKII may play a role in bupivacaine hydrochloride-induced SH-SY5Y cells injury, which is related with upregulated Cav3.1 protein expression.

Apoptosis ; Bupivacaine ; adverse effects ; Calcium Channels, T-Type ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; antagonists & inhibitors ; metabolism ; Cell Line ; Cell Survival ; Humans ; Up-Regulation

Abnormal enhanced transmural dispersion of repolarization (TDR) plays an important role in the maintaining of the severe ventricular arrhythmias such as torsades de pointes (TDP) which can be induced in long-QT (LQT) syndrome. Taking advantage of an in vitro rabbit model of LQT2, we detected the effects of KN-93, a CaM-dependent kinase (CaMK) II inhibitor on repolarization heterogeneity of ventricular myocardium. Using the monophasic action potential recording technique, the action potentials of epicardium and endocardium were recorded in rabbit cardiac wedge infused with hypokalemic, hypomagnesaemic Tyrode's solution. At a basic length (BCL) of 2000 ms, LQT2 model was successfully mimicked with the perfusion of 0.5 μmol/L E-4031, QT intervals and the interval from the peak of T wave to the end of T wave (Tp-e) were prolonged, and Tp-e/QT increased. Besides, TDR was increased and the occurrence rate of arrhythmias like EAD, R-on-T extrasystole, and TDP increased under the above condition. Pretreatment with KN-93 (0.5 μmol/L) could inhibit EAD, R-on-T extrasystole, and TDP induced by E-4031 without affecting QT interval, Tp-e, and Tp-e/QT. This study demonstrated KN-93, a CaMKII inhibitor, can inhibit EADs which are the triggers of TDP, resulting in the suppression of TDP induced by LQT2 without affecting TDR.
Action Potentials ; drug effects ; Animals ; Anti-Arrhythmia Agents ; pharmacology ; Arrhythmias, Cardiac ; etiology ; physiopathology ; prevention & control ; Benzylamines ; pharmacology ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; antagonists & inhibitors ; metabolism ; Electrocardiography ; Electrophysiologic Techniques, Cardiac ; Endocardium ; drug effects ; physiopathology ; Heart ; drug effects ; physiopathology ; In Vitro Techniques ; Long QT Syndrome ; complications ; Pericardium ; drug effects ; physiopathology ; Piperidines ; pharmacology ; Protein Kinase Inhibitors ; pharmacology ; Pyridines ; pharmacology ; Rabbits ; Sulfonamides ; pharmacology ; Torsades de Pointes ; etiology ; physiopathology ; prevention & control

BACKGROUNDVolatile anesthetics (VAs) may affect varied and complex physiology processes by manipulating Ca(2+)-calmodulin (CaM). However, the detailed mechanism about the action of VAs on CaM has not been elucidated. This study was undertaken to examine the effects of VAs on the conformational change, hydrophobic site, and downstream signaling pathway of CaM, to explore the possible mechanism of anesthetic action of VAs.

METHODSReal-time second-harmonic generation (SHG) was performed to monitor the conformational change of CaM in the presence of VAs, each plus 100 µmol/L Ca(2+). A hydrophobic fluorescence indicator, 8-anilinonaphthalene-1-sulfonate (ANS), was utilized to define whether the VAs would interact with CaM at the hydrophobic site or not. High-performance liquid chromatography (HPLC) was carried out to analyze the activity of CaM-dependent phosphodiesterase (PDE1) in the presence of VAs. The VAs studied were ether, enflurane, isoflurane, and sevoflurane, with their aqueous concentrations 7.6, 9.5, 11.4 mmol/L; 0.42, 0.52, 0.62 mmol/L; 0.25, 0.31, 0.37 mmol/L and 0.47, 0.59, 0.71 mmol/L respectively, each were equivalent to their 0.8, 1.0 and 1.2 concentration for 50% of maximal effect (EC50) for general anesthesia.

RESULTSThe second-harmonic radiation of CaM in the presence of Ca(2+) was largely inhibited by the VAs. The fluorescence intensity of ANS, generated by binding of Ca(2+) to CaM, was reversed by the VAs. HPLC results also showed that AMP, the product of the hydrolysis of cAMP by CaM-dependent PDE1, was reduced by the VAs.

CONCLUSIONSOur findings demonstrate that the above VAs interact with the hydrophobic core of Ca(2+)-CaM and the interaction results in the inhibition of the conformational change and activity of CaM. This in vitro study may provide us insight into the possible mechanism of anesthetic action of VAs in vivo.

Adenosine Monophosphate ; analysis ; Anesthetics, Inhalation ; pharmacology ; Anilino Naphthalenesulfonates ; Calmodulin ; antagonists & inhibitors ; chemistry ; physiology ; Cyclic Nucleotide Phosphodiesterases, Type 1 ; analysis ; Fluorescence ; Humans ; Hydrophobic and Hydrophilic Interactions

Auto-transplantation of adipose tissue is commonly used for the treatment of tissue defects in plastic surgery. The survival of the transplanted adipose tissue is not always constant, and one of reasons is the accelerated apoptosis of the implanted preadipocytes. We have recently established highly homogeneous preadipocytes, named ccdPAs. The aim of the current study was to evaluate the regulation of the potency of platelet-rich plasma (PRP) on the apoptosis of ccdPAs in vitro. PRP stimulated the proliferation of the preadipocytes in a dose-dependent manner, and the stimulatory activity of 2% PRP was significantly higher than that of 2% FBS or 2% platelet-poor plasma (PPP). The presence of 2% PRP significantly inhibited serum starvation- or TNF-alpha/cycloheximide-induced apoptosis in comparison to 2% FBS or 2% PPP. DAPK1 and Bcl-2-interacting mediator of cell death (BIM) mRNAs were reduced in the preadipocytes cultured with 2% PRP in comparison to those cultured in 2% FBS. The gene expression levels were significantly higher in cells cultured without serum in comparison to cells cultured with 2% FBS, and the levels in the cells with 2% PRP were reduced to 5-10% of those in the cells without serum. These results indicated that ccdPAs exhibit anti-apoptotic activities, in addition to increased proliferation, when cultured in 2% PRP in comparison to the same concentration of FBS, and that this was accompanied with reduced levels of DAPK1 and BIM mRNA expression in in vitro culture. PRP may improve the outcome of transplantation of adipose tissue by enhancing the anti-apoptotic activities of the implanted preadipocytes.
Adipocytes/*cytology ; Adipose Tissue/cytology/metabolism ; Apoptosis/*physiology ; Apoptosis Regulatory Proteins/antagonists & inhibitors/metabolism ; Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors/metabolism ; Cell Culture Techniques/*methods ; *Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Gene Expression Regulation ; Humans ; Membrane Proteins/antagonists & inhibitors/metabolism ; *Platelet-Rich Plasma/metabolism/physiology ; Proto-Oncogene Proteins/antagonists & inhibitors/metabolism ; Tissue Transplantation

Cardiac hypertrophy is an independent risk factor for sudden cardiac death in clinical settings and the incidence of sudden cardiac death and ventricular arrhythmias are closely related. The aim of this study was to determine the effects of the calmodulin-dependent protein kinase (CaMK) II inhibitor, KN-93, on L-type calcium current (I(Ca, L)) and early after-depolarizations (EADs) in hypertrophic cardiomyocytes. A rabbit model of myocardial hypertrophy was constructed through abdominal aortic coarctation (LVH group). The control group (sham group) received a sham operation, in which the abdominal aortic was dissected but not coarcted. Eight weeks later, the degree of left ventricular hypertrophy (LVH) was evaluated using echocardiography. Individual cardiomyocyte was isolated through collagenase digestion. Action potentials (APs) and I(Ca, L) were recorded using the perforated patch clamp technique. APs were recorded under current clamp conditions and I(Ca, L) was recorded under voltage clamp conditions. The incidence of EADs and I(ca, L) in the hypertrophic cardiomyocytes were observed under the conditions of low potassium (2 mmol/L), low magnesium (0.25 mmol/L) Tyrode's solution perfusion, and slow frequency (0.25-0.5 Hz) electrical stimulation. The incidence of EADs and I(ca, L) in the hypertrophic cardiomyocytes were also evaluated after treatment with different concentrations of KN-92 (KN-92 group) and KN-93 (KN-93 group). Eight weeks later, the model was successfully established. Under the conditions of low potassium, low magnesium Tyrode's solution perfusion, and slow frequency electrical stimulation, the incidence of EADs was 0/12, 11/12, 10/12, and 5/12 in sham group, LVH group, KN-92 group (0.5 μmol/L), and KN-93 group (0.5 μmol/L), respectively. When the drug concentration was increased to 1 μmol/L in KN-92 group and KN-93 group, the incidence of EADs was 10/12 and 2/12, respectively. At 0 mV, the current density was 6.7±1.0 and 6.3±0.7 PA·PF(-1) in LVH group and sham group, respectively (P>0.05, n=12). When the drug concentration was 0.5 μmol/L in KN-92 and KN-93 groups, the peak I(Ca, L) at 0 mV was decreased by (9.4±2.8)% and (10.5±3.0)% in the hypertrophic cardiomyocytes of the two groups, respectively (P>0.05, n=12). When the drug concentration was increased to 1 μmol/L, the peak I(Ca, L) values were lowered by (13.4±3.7)% and (40±4.9)%, respectively (P<0.01, n=12). KN-93, a specific inhibitor of CaMKII, can effectively inhibit the occurrence of EADs in hypertrophic cardiomyocytes partially by suppressing I(Ca, L), which may be the main action mechanism of KN-93 antagonizing the occurrence of ventricular arrhythmias in hypertrophic myocardium.
Animals ; Benzylamines ; pharmacology ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; antagonists & inhibitors ; metabolism ; Cardiomegaly ; metabolism ; physiopathology ; Female ; Myocytes, Cardiac ; drug effects ; metabolism ; physiology ; Rabbits ; Sulfonamides ; pharmacology

OBJECTIVETo investigate the effects of the calmodulin inhibitor W-7 on the expression of the key marker of ERS GRP78 and neuronal apoptosis in the immature rat hippocampus after status convulsion (SC).

METHODSOne hundred and seventeen male Sprague-Dawley rats aged 19-21 days were randomly divided into three groups: normal saline control (control), SC with and without W-7 pretreatment. Each of the 3 groups was further subdivided into subgroups sacrificed at 4, 24 and 48 hrs. SC model was prepared using lithium-pilocarpine. GRP78 mRNA expression in the hippocampus was detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). GRP78 protein was ascertained by immunohistochemistry. Neuronal apoptosis was observed with TdT-mediated dUTP nick end labeling (TUNEL).

RESULTSThe expression of GRP78 mRNA was significantly increased in the non-pretreated SC group compared with the control group 24 hrs after injection of saline or lithium-pilocarpine (P<0.01), and the expression of GRP78 protein also increased markedly in the seizure group compared with the control group 24 and 48 hrs after the injection (P<0.01). The expression of GRP78 mRNA and protein in the W-7 pretreatment group was significantly higher than both the control and the non-pretreated seizure groups 24 and 48 hrs after injection. The TUNEL positive cells in the hippocampus CA1 in the non-pretreated SC group 24 and 48 hrs after injection (21.0 ± 2.5 and 29.4 ± 2.8, respectively) were increased compared to the control group (7.1 ± 1.4 and 7.3 ± 1.6, respectively; P<0.01). W-7 pretreatment decreased TUNEL positive cells to 15.0 ± 2.5 and 20.0 ± 2.9 at 24 and 48 hrs after injection compared to the non-pretreated seizure group (P<0.01), but the number of TUNEL positive cells in the W-7 pretreatment group remained significantly greater than in the control group (P<0.01).

CONCLUSIONSW-7 may up-regulate the expression of GRP78 and reduce the number of apoptotic neurons, thus provides a neuroprotective effect against brain damage following SC.

Animals ; Apoptosis ; drug effects ; Calcium-Calmodulin-Dependent Protein Kinase Kinase ; antagonists & inhibitors ; Heat-Shock Proteins ; genetics ; Hippocampus ; metabolism ; In Situ Nick-End Labeling ; Male ; Neurons ; drug effects ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Status Epilepticus ; metabolism ; Sulfonamides ; pharmacology

OBJECTIVETo investigate the effect of calmodulin antagonist O-(4-ethoxyl-butyl)-berbamine (EBB) on proliferation of human breast cancer cell MCF-7 and its possible mechanism.

METHODSMTT assay was used to analyze the effect of EBB on tumor cells growth. Flow cytometry was used to detect its impact on the cell cycle of MCF-7 cells. Immunofluoresce labeling technique and laser scanning confocal microscope were used to reveal the changes of the microtubule, microfilament, mitochondrion, and endoplasmic reticulum in the cells.

RESULTSThe IC50 value of EBB in MCF-7 cells was (13.0 +/- 3.7) micromol/L. MCF-7 cells were arrested at S phase after EBB treatment. Meanwhile, depolymerization of the microtubule and microfilament, impairment of the mitochondrion and swelling of endoplasmic reticulum were observed.

CONCLUSIONEBB arrests MCF-7 cells at S phase by inhibiting the growth of MCF-7 cells, which may be related to the changes of structures and functions of the microtubule, microfilament, mitochondrion, and endoplasmic reticulum.

Benzylisoquinolines ; pharmacology ; Breast Neoplasms ; pathology ; Calmodulin ; antagonists & inhibitors ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Female ; Humans

OBJECTIVETo investigate the methylation status of the promoter of resion death associated protein kinase (DAPK) gene in bladder cancer cell (T24), and study the effect of 5-aza-2'-deoxycytidine (5-aza-dc) on DAPK gene reactive expression in T24 and its inhibitory effect on T24.

METHODSThe bladder cancer cell T24 was treated with different doses of 5-aza-dc. The inhibitory effect and apoptosis rate were detected by MTT and flow cytometry, and the changes of DAPK mRNA and protein expression and the methylation status of DAPK promoter were assessed by RT-PCR, Western blotting, and methylation specific PCR, respectively.

RESULTSThe growth of bladder cancer cell was inhibited significantly and the maximal apoptosis rate detected by flow cytometry was (24.12-/+1.4)%. DAPK mRNA was not expressed in bladder cancer cell T24 in normal conditions. DAPK mRNA and protein re-expressed after 5-aza-dc (12.5 micromol/L) treatment in cell line T24 for 24 h, and DAPK promoter became unmethylated.

CONCLUSIONSThe promoter methylation can be an important factor for silencing the expression of DAPK in bladder cancer cell. 5-aza-dc can inhibit the growth and induce apoptosis of bladder cancer cells through reversing unmethylation status of DAPK promoter.

Apoptosis Regulatory Proteins ; genetics ; metabolism ; Azacitidine ; analogs & derivatives ; pharmacology ; Calcium-Calmodulin-Dependent Protein Kinases ; genetics ; metabolism ; Cell Line, Tumor ; DNA Methylation ; DNA Modification Methylases ; antagonists & inhibitors ; Death-Associated Protein Kinases ; Humans ; Promoter Regions, Genetic ; genetics ; RNA, Messenger ; genetics ; metabolism ; Transcriptional Activation ; drug effects ; Urinary Bladder Neoplasms ; metabolism ; pathology

Calcium-Calmodulin-Dependent Protein Kinases ; antagonists & inhibitors ; Carcinoma ; pathology ; Cell Cycle ; drug effects ; Cell Line ; Cell Line, Tumor ; Enzyme Inhibitors ; pharmacology ; Female ; Flavonoids ; pharmacology ; Gene Expression Regulation ; drug effects ; Humans ; Ovarian Neoplasms ; pathology ; Proto-Oncogene Proteins c-fos ; genetics ; metabolism

OBJECTIVETo investigate the possible involvement of calmodulin in mouse sperm capacitation.

METHODSCalmodulin antagonists W7 at the concentrations of 50, 100 and 200 micromol/L and calmidazolium (CZ) at the concentrations of 10, 20 and 30 micromol/ L, were coincubated with mouse sperm for 2 hours, respectively. The percentage of pattern B sperm was measured by chlorotetracycline staining. Then the sperm were coincubated with 100 micromol/L W7 or 10 micromol/L calmidazolium (CZ) before acrosome reaction was induced by 5 micromol/L progesterone and evaluated by the same method.

RESULTSAfter the treatment of the sperm with different concentrations of CZ or W7, the percentages of pattern B sperm decreased in a dose-dependent manner, significantly different from the control (P < 0.05). There was a statistic difference in the rate of acrosome reaction between the experiment and the control group (P < 0.01).

CONCLUSIONCalmodulin is a key protein involved in mouse sperm capacitation.

Animals ; Calmodulin ; antagonists & inhibitors ; Enzyme Inhibitors ; pharmacology ; Imidazoles ; pharmacology ; Male ; Mice ; Mice, Inbred ICR ; Sperm Capacitation ; drug effects ; Sperm Count ; Sperm Motility ; drug effects ; Spermatids ; cytology ; drug effects ; physiology