BACKGROUND: Sarcoplasmic reticulum calcium ATPase 2a (SERCA2a) is a key protein that maintains myocardial Ca 2+ homeostasis. The present study aimed to investigate the mechanism underlying the SERCA2a-SUMOylation (small ubiquitin-like modifier) process after ischemia/reperfusion injury (I/RI) in vitro and in vivo . METHODS: Calcium transient and systolic/diastolic function of cardiomyocytes isolated from Serca2a knockout (KO) and wild-type mice with I/RI were compared. SUMO-relevant protein expression and localization were detected by quantitative real-time PCR (RT-qPCR), Western blotting, and immunofluorescence in vitro and in vivo . Serca2a-SUMOylation, infarct size, and cardiac function of Senp1 or Senp2 overexpressed/suppressed adenovirus infected cardiomyocytes, were detected by immunoprecipitation, triphenyltetrazolium chloride (TTC)-Evans blue staining, and echocardiography respectively. RESULTS: The results showed that the changes of Fura-2 fluorescence intensity and contraction amplitude of cardiomyocytes decreased in the I/RI groups and were further reduced in the Serca2a KO + I/RI groups. Senp1 and Senp2 messenger ribose nucleic acid (mRNA) and protein expression levels in vivo and in cardiomyocytes were highest at 6 h and declined at 12 h after I/RI. However, the highest levels in HL-1 cells were recorded at 12 h. Senp2 expression increased in the cytoplasm, unlike that of Senp1. Inhibition of Senp2 protein reversed the I/RI-induced Serca2a-SUMOylation decline, reduced the infarction area, and improved cardiac function, while inhibition of Senp1 protein could not restore the above indicators. CONCLUSION I/RI activated Senp1 and Senp2 protein expression, which promoted Serca2a-deSUMOylation, while inhibition of Senp2 expression reversed Serca2a-SUMOylation and improved cardiac function.
Animals ; Mice ; Calcium/metabolism* ; Cysteine Endopeptidases/metabolism* ; Myocardial Reperfusion Injury/metabolism* ; Myocardium/metabolism* ; Myocytes, Cardiac/metabolism* ; Proteins/metabolism* ; Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics*

The present study is aimed to study the effect of sarcoplasmic reticulum Ca(2+)-ATPase 2a (SERCA2a) gene transfer on the contractile function of isolated cardiomyocytes of canines. The cardiomyocytes were isolated with collagenases. The isolated cardiac cells were divided into untransfected group, empty vector group and SERCA2a-transfected group. Recombinant adenovirus vector carrying enhanced green fluorescent protein gene was used for SERCA2a gene delivery. The expression of SERCA2a protein in cardiomyocytes was determined by Western blot. Contractile function of cardiomyocytes was measured with motion edge-detection system of single cell at 48 h after transfection. The results showed, compared with untransfected group, SERCA2a protein level, percentage of peak contraction amplitude under normal condition, percentages of peak contraction amplitude under Ca(2+) or isoproterenol stimulation, time-to-peak contraction (TTP) and time-to-50% relaxation (R50) in SERCA2a-transfected group all increased significantly. While all the above indices in empty vector group did not show any differences with those in untransfected group. These results suggest that the overexpression of SERCA2a by gene transfer may enhance the contraction function of canine myocardial cells.
Adenoviridae ; genetics ; metabolism ; Animals ; Dogs ; Male ; Myocardial Contraction ; drug effects ; physiology ; Myocytes, Cardiac ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; genetics ; metabolism ; Transfection

AIMTo investigate the changes in the expression of four kinds of calcium regulatory proteins mRNA on the isolated ischemia/ reperfusion (IR) hearts.

METHODSThe rat hearts were divided into two groups: control group and IR group which received 45 min exposure to Krebs-Henseleit solution after 15 min zero-flow global ischemia. The indexes of left ventricular function, such as LVDP, +dp/dt(max), -dp/dt(max), and an arrhythmia scoring system were compared between the two groups. The messenger ribonucleic acid (mRNA) amount of sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA), phospholamban (PLB), inositol 1,4,5-trisphosphate receptor2 (IP3R2) and ryanodine receptor2 (RyR2) was measured by reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA levels of beta-actin.

RESULTSIn the IR group, LVDP, +dp/dt(max) and -dp/dt(min) of the isolated hearts were depressed and the high rate of arrhythmias occurred during reperfusion. The levels of SERCA, IP3R2, RyR2 mRNA were lower in the IR isolated hearts group than those in the control group, while there was no difference in the level of phospholamban.

CONCLUSIONThese data suggest that myocardial ischemia/reperfusion can induce the depression of cardiac performance and an increased risk of arrhythmias, concomitant with the decrease in SERCA, IP3R2, RyR2 mRNA steady state levels.

Animals ; Myocardial Reperfusion Injury ; metabolism ; Myocardium ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; genetics ; metabolism

OBJECTIVETo study the therapy effect of adeno-associated viral gene transfer of sarcoplasmic reticulum Ca(2+)-ATPase 2a (SERCA2a) on chronic congestive heart failure (HF) in 30 days, and the possible mechanism of the therapy effect.

METHODSThe rats were divided into four groups: control group, HF group, Group HF + EGFP, and Group HF + SERCA2a. HF rats were obtained by creating descending aortic constriction. 0.9% sodium chloride solution, recombinant adeno-associated virus carrying enhanced green fluorescent protein gene (rAAV2.eGFP) and recombinant adeno-associated virus carrying SERCA2a gene (rAAV2.SERCA2a), were respectively delivered to pericardium of HF rats in different groups by intrapericardial injection with a trans-diaphragmatic approach. 30 days after gene transfer, hemodynamic parameters, SERCA2a protein expression and SERCA2a activity were analyzed. The proteome difference from rat hearts between Groups HF + SERCA2a and HF was detected by expression proteomics. Electrophoretic separation and quantitation of cardiac myosin heavy chain isoforms of hearts in different groups were performed at 30 days.

RESULTSAt 30 days, left ventricular function improved significantly in HF rats infected with rAAV2.SERCA2a (LVSP 146.52 +/- 13.86 vs 97.91 +/- 12.13, LVEDP 7.88 +/- 2.88 vs 21.15 +/- 3.57, LV +dp/dt 11 206.16 +/- 1730.11 vs 5948.93 +/- 1283.43, LV -dp/dt -8249.54 +/- 1076.09 vs -4497.50 +/- 652.12; P < 0.05). The recovered cardiac function in Group HF + SERCA2a rats was comparable to control rats, and had lower LV-weight/Body-weight ratio (2.46 +/- 0.17 vs 2.71 +/- 0.24, P < 0.05). Overexpression of SERCA2a increased both the protein content (0.39 +/- 0.11 vs 1.11 +/- 0.18, P < 0.05) and activity (228.62 +/- 25.11 vs 82.55 +/- 14.13, P < 0.05) up to nonfailing levels. Expressions of some energy metabolic enzymes in hearts of Group HF + SERCA2a were much higher than those of HF group. They included creatine kinase-muscle, enolase beta, fructose-bisphosphate aldolase, mitochondrial H(+)-ATP synthase alpha subunit, electron transfer flavoprotein alpha-subunit, H(+)-transporting ATP synthase and heart fatty acid binding protein. Downregulation of alpha-MHC and upregulation of beta-MHC in failing hearts were observed. Gene transfer of SERCA2a could increase the expression of alpha-MHC [(74.48 +/- 3.74)% vs (53.57 +/- 2.30)%, P < 0.05], and decrease the expression of beta-MHC [(25.52 +/- 3.74)% vs (46.43 +/- 2.30)%, P < 0.05] in HF rats. The expression profiles of alpha-MHC and beta-MHC and the ratio of alpha-MHC/beta-MHC were similar to those in controls.

CONCLUSIONSAdeno-associated viral gene transfer of SERCA2a can enhance SERCA2a functions, maintain calcium homeostasis, improve cardiac energy metabolism, and normalize the expression of cardiac myosin heavy chain isoforms in HF rats. As a result, the ventricular systolic and diastolic functions can be improved significantly, and the hypertrophy of the heart may be reduced in clinic. Adeno-associated viral gene transfer of SERCA2a demonstrated good therapy effects on HF rats.

Adenoviridae ; genetics ; Animals ; Calmodulin ; metabolism ; Disease Models, Animal ; Gene Transfer Techniques ; Genetic Therapy ; Heart Failure ; therapy ; Male ; Rats ; Rats, Sprague-Dawley ; Sarcoplasmic Reticulum ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; genetics

PURPOSE: The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA), encoded by ATP2A2, is an essential component for G-protein coupled receptor (GPCR)-dependent Ca(2+) signaling. However, whether the changes in Ca(2+) signaling and Ca(2+) signaling proteins in parotid acinar cells are affected by a partial loss of SERCA2 are not known. MATERIALS AND METHODS: In SERCA2(+/-) mouse parotid gland acinar cells, Ca(2+) signaling, expression levels of Ca(2+) signaling proteins, and amylase secretion were investigated. RESULTS: SERCA2(+/-) mice showed decreased SERCA2 expression and an upregulation of the plasma membrane Ca(2+) ATPase. A partial loss of SERCA2 changed the expression level of 1, 4, 5-tris-inositolphosphate receptors (IP(3)Rs), but the localization and activities of IP3Rs were not altered. In SERCA2(+/-) mice, muscarinic stimulation resulted in greater amylase release, and the expression of synaptotagmin was increased compared to wild type mice. CONCLUSION: These results suggest that a partial loss of SERCA2 affects the expression and activity of Ca(2+) signaling proteins in the parotid gland acini, however, overall Ca(2+) signaling is unchanged.
Amylases/metabolism ; Animals ; Blotting, Western ; Calcium/metabolism ; Calcium Signaling/drug effects/genetics/*physiology ; Carbachol/pharmacology ; Immunohistochemistry ; Inositol 1,4,5-Trisphosphate Receptors/metabolism ; Mice ; Mice, Knockout ; Parotid Gland/*metabolism ; Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics/*metabolism ; Signal Transduction/drug effects/genetics/physiology

OBJECTIVETo explore the effects of tumor necrosis factor alpha (TNFalpha) on the expression of phospholamban (PLB) and sarco (endo) plasmic reticulum Ca(2+)-ATPase (SERCA2a) and concentration of intracellular free calcium in myocardiocytes.

METHODSThe neonatal rat myocardiocytes were randomly divided into 6 groups: treatment with different concentrations of TNFalpha (1,10,30,50,and 70 microg/L, respectively) and without TNFalpha (control). The mRNA and protein expression of PLB and SERCA2a were detected with one-step reverse transcription-polymerase chain reaction and Western blotting. The changes of intracellular free calcium concentration ([Ca2+]i) in cultured single neonatal rat cardiomyocyte were determined with Fluo-3/AM loading by laser scanning confocal microscopy. RESULTS TNFalpha significantly increased the expression of PLB mRNA and protein in a dose-dependent fashion. The ratio of PLB/beta-actin mRNA in myocardiocytes incubated with 10,30,50, and 70 microg/L TNFalpha significantly increased by 66%, 106%, 141%, and 189% compared with control (P < 0.05), and protein levels significantly increased by 30%, 48%, 73%, and 114% respectively compared with control (P < 0.001), but there was no significant difference in PLB mRNA expression between the group treated with 1 microg/L TNFalpha and control group. TNFalpha had no effect on the expression of mRNA and protein of SERCA2a. TNFalpha (50 microg/L) incubated with cell for 24 hours diminished delta[Ca2+]i of single neonatal rat cardiomyocyte about 33% stimulated by isoproterenol (P < 0.01), but had no effect on delta [Ca2+]i of cardiomyocyte without isoproterenol stimulation.

CONCLUSIONTNFalpha can increase the expression of PLB and decrease delta[Ca2+]i in cardiomyocytes, which may be related with its negative inotropic effects on cardiomyocytes.

Animals ; Calcium ; metabolism ; Calcium-Binding Proteins ; biosynthesis ; genetics ; Cells, Cultured ; Female ; Male ; Myocytes, Cardiac ; drug effects ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Wistar ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; biosynthesis ; genetics ; Tumor Necrosis Factor-alpha ; pharmacology

BACKGROUNDChronic heart failure (CHF) is associated with calcium transients and calcium handling proteins. Angiotensin converting enzyme (ACE) inhibitor has been demonstrated to have beneficial effect on CHF. Yet studies addressed to the relationship between ACE inhibitor and calcium transients in CHF are rare. The aim of this study was to investigate the influence of ACE inhibitor (perindopril) on the contractility and calcium transients and calcium handling proteins in ventricular myocytes from rats with experimental heart failure.

METHODSMale Wistar rats were randomized to heart failure group treated with perindopril [CHF-T, 3 mg.kg(-1).d(-1)], heart failure group without treatment (CHF-C) and sham-operated group (PS). Heart failure was induced by abdominal aortic constriction. All groups were further followed up for 12 weeks. Left ventricular myocytes were then isolated. Single cell shortening fraction and [Ca(2+)]i were simultaneously measured by laser scanning confocal microscope under the field stimulation (1.0 Hz). Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate the changes of mRNA and protein of Na(+)-Ca(2+) exchanger (NCX1), sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2) and phospholamban (PLB).

RESULTSThe fraction of cell shortening (FS%) and [Ca(2+)]imax (nmol/L) were significantly reduced in group CHF-C compared with group PS (FS%: 7.51 +/- 1.15 vs 13.21 +/- 1.49; [Ca(2+)]i max: 330.85 +/- 50.05 vs 498.16 +/- 14.07; both P < 0.01), and restored at least partially in CHF-T group. In CHF-C group, the left ventricular mRNA of NCX1 and PLB were significantly upregulated in comparing with PS group (RNCX1/beta-Actin: 0.51 +/- 0.12 vs 0.19 +/- 0.06, P < 0.01; RPLB/beta-Actin: 0.26 +/- 0.12 vs 0.20 +/- 0.08, P < 0.05), while SERCA2 mRNA was downregulated (0.48 +/- 0.10 vs 0.80 +/- 0.11, P < 0.01). The mRNA levels of NCX1 and SERCA2 in CHF-T group were between the CHF-C and PS group, and the differences of the latter two groups were significant (all P < 0.05). In CHF-C and CHF-T groups, the protein expression of NCX1 were 1.141 +/- 0.047 and 1.074 +/- 0.081 times of that in PS group respectively (both P < 0.05), and SERCA2 protein levels were 0.803 +/- 0.100 and 0.893 +/- 0.084 times of that in PS group respectively (both P < 0.05). The protein expression of NCX1 and SERCA2 in the CHF-C and CHF-T groups is significantly different (both P < 0.05).

CONCLUSIONACE inhibitor could improve cardiac function of failing heart through directly enhancing the contractility of single cardiomyocyte, and these effects are probably mediated by its roles in preventing the deleterious changes of calcium transients and calcium handling proteins in CHF.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Calcium ; metabolism ; Calcium-Binding Proteins ; genetics ; Calcium-Transporting ATPases ; genetics ; Heart Failure ; drug therapy ; metabolism ; Heart Ventricles ; drug effects ; Male ; Myocytes, Cardiac ; drug effects ; metabolism ; Perindopril ; pharmacology ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; Sodium-Calcium Exchanger ; genetics

OBJECTIVETo study the effect of phospholamban antisense RNA (asPLB) on sarcoplasmic reticulum Ca2+-ATPase activity and cardiac function in rats with diabetes mellitus (DM) mediated by recombinant adeno-associated virus (rAAV) vector.

METHODSSix weeks after the induction of DM by streptozotocin injected intraperitoneally, the rats were divided into three groups, namely: DM-rAAV-asPLB group, DM-saline group and DM group (control group). The rats in the DM-rAAV-asPLB group were intramyocardially injected with rAAV-asPLB, the rats in the DM-saline group were injected with saline, and those in the control group did not receive any treatment. Six weeks after gene transfer, the expressions of PLB protein and PLB phosphorylation were detected by Western-blot, while the activity of sarcoplasmic reticulum (SR) Ca2+-ATPase and left ventricular function were measured.

RESULTSThe PLB protein expression level was significantly higher whereas the PLB phosphorylation, SR Ca2+-ATPase activity and left ventricular function were significantly lower in the DM-saline group than in the control group. No significant difference was found in PLB protein expression level, PLB phosphorylation or SR Ca2+-ATPase activity between the DM-rAAV-asPLB group and the control group. The left ventricular function in the DM-rAAV-asPLB group was poorer than in the control group and was better than in the DM-saline group.

CONCLUSIONrAAV-asPLB can down-regulate PLB protein expression and up-regulate PLB phosphorylation and SR Ca2+-ATPase activity, thus contributing to the improvement of in vivo left ventricular function.

Animals ; Calcium-Binding Proteins ; genetics ; metabolism ; Diabetes Mellitus, Experimental ; metabolism ; Male ; Phosphorylation ; RNA, Antisense ; administration & dosage ; Rats ; Rats, Wistar ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; metabolism ; Ventricular Function, Left ; drug effects

OBJECTIVETo investigate changes in the expression of sarcoplamic reticular Ca(2+)-ATPase (SERCA) and IP(3)-I receptors (IP(3)R(1)) mRNA in patients with atrial fibrillation.

METHODSThirty-eight patients with mitral stenosis undergoing open heart surgery were studied. 100 mg of atrial tissue was obtained during surgery from the right appendage and the right atrium. The amount of messenger ribonucleic acid (mRNA) amount of SERCA and IP(3)R(1) was measured by reverse transcription-polymerase chain reaction (RT-PCR) and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase (GAPDH).

RESULTSLevels of mRNA expression of SERCA in patients with AF, as compared with subjects in sinus rhythm, was lower and that of IP(3)R(1) was higher. The longer AF was sustained, the higher the levels of mRNA. There was no significant difference between right atrial free wall and right appendage.

CONCLUSIONSThe expression changes of SERCA and IP3R mRNA may correlate with the initiation or maintenance of AF.

Adult ; Aged ; Atrial Fibrillation ; genetics ; pathology ; Calcium Channels ; genetics ; Calcium-Transporting ATPases ; genetics ; Female ; Gene Expression ; Humans ; Inositol 1,4,5-Trisphosphate Receptors ; Male ; Middle Aged ; RNA, Messenger ; genetics ; metabolism ; Receptors, Cytoplasmic and Nuclear ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Sarcoplasmic Reticulum Calcium-Transporting ATPases

BACKGROUNDHeart failure (HF) is a major cause of morbidity and mortality worldwide, but current treatment modalities cannot reverse the underlying pathological state of the heart. Gene-based therapies are emerging as promising therapeutic modalities in HF patients. Our previous studies have shown that recombinant adeno-associated viral (rAAV) gene transfer of Sarco-endoplasmic reticulum calcium ATPase (SERCA2a) can be effective in treating rats with chronic heart failure (CHF). The aim of this study was to examine the effects of SERCA2a gene transfer in a large HF animal model.

METHODSHF was induced in beagles by rapid right ventricular pacing (230 beats/min) for 30 days. A reduced rate ventricular pacing (180 beats/min) was continued for another 30 days. The beagles were assigned to four groups: (a) control group (n = 4); (b) HF group (n = 4); (c) enhanced green fluorescent protein group (n = 4); and (d) SERCA2a group (n = 4). rAAV1-EGFP (1 x 10(12) microg) and rAAV1-SERCA2a (1 x 10(12) microg) were delivered intramyocardially. SERCA2a expression was assessed by Western blotting and immunohistochemistry.

RESULTSFollowing 30 days of SERCA2a gene transfer in HF beagles its protein expression was significantly higher than in the HF group than in the control group (P < 0.05). Heart function improved along with the increase in SERCA2a expression. Left ventricular systolic function significantly improved, including the ejection fraction, left ventricular systolic pressure, maximal rate of rise of left ventricular pressure (+dp/dt(max)), and the maximal rate of decline of left ventricular pressure (-dp/dt(max)) (P < 0.05). Left ventricular end-diastole pressure significantly decreased (P < 0.05). The expression of SERCA2a in the myocardial tissue was higher in the SERCA2a group than in the HF group (P < 0.05).

CONCLUSIONSIntramyocardial injection of rAAV1-SERCA2a can improve the cardiac function in beagles induced with HF. We expect further studies on SERCA2a's long-term safety, efficacy, dosage and the optimization before using it in humans with HF.

Animals ; Blotting, Western ; Disease Models, Animal ; Dogs ; Echocardiography ; Genetic Therapy ; methods ; Green Fluorescent Proteins ; genetics ; metabolism ; Heart ; physiology ; Heart Failure ; therapy ; Hemodynamics ; Immunohistochemistry ; Myocardium ; metabolism ; Sarcoplasmic Reticulum Calcium-Transporting ATPases ; genetics ; physiology