OBJECTIVETo investigate the negative regulation of microRNA-1 (miR-1) on L-type calcium channel beta2 subunit (Cavbeta 2) during cardiomyocyte hypertrophy and its mechanism.

METHODSCardiomyocyte hypertrophy was induced by isoproterenol (ISO). The cell surface area was measured by image analysis system (HJ2000). The targets of miR-1 were predicted by online database microCosm. The 3' untranslated region sequence of Cavbeta 2 was cloned into luciferase reporter vector and then transiently transfected into HEK293 cells. The luciferase activities of samples were measured to verify the expression of luciferase reporter vector. The expression of atrial natriuretic peptide (ANP), beta-myosin heavy chain (beta-MHC), miR-1 and the Cavbeta 2 mRNA were detected by qRT-PCR. The protein expression of Cavbeta 2 was detected by Western blot. The level of miR-1 was up-regulated by miR-1 mimic transfection and the expression level of Cavbeta 2 was down-regulated by RNAi, then effects of which on cardiomyocyte hypertrophy were investigated.

RESULTS(1) The expression of miR-1 was significantly reduced in cardiomyocyte hypertrophy. Upregulating the miR-1 level could suppress the increase of cell surface area, the expression of ANP and beta-MHC mRNA (P < 0.05). (2) Cavbeta 2 was the one of potential targets of miR-1 by prediction using online database microCosm. The luciferase activities of HEK293 cells with the plasmid containing miR-1 and wide type Cavbeta 3' UTR sequence was significantly decreased when compared with that of control group (P < 0.01). Up-regulation of the miR-1 level could suppress the protein expression of Cavbeta 2. (3) The expression of Cavbeta 2 was significantly increased in cardiomyocyte hypertrophy induced by ISO. Downregulation of Cavbeta by RNAi could markedly inhibit the increase of cell surface area, the expression of ANP and beta-MHC mRNA.

CONCLUSIONCavbeta2 is one of potential targets of miR-1 by bioinformatics prediction. The experiment data confirms that Cavbeta2 is truly the target of miR-1. MiR-1 can negatively regulate the expression of Cavbeta 2, resulting in the decrease of intracellular Ca2+ content and the attenuation of cardiomyocyte hypertrophy.

Animals ; Atrial Natriuretic Factor ; metabolism ; Calcium Channels, L-Type ; genetics ; Cardiomegaly ; genetics ; Gene Expression Regulation ; HEK293 Cells ; Humans ; MicroRNAs ; genetics ; Rats ; Rats, Sprague-Dawley ; Transfection ; Ventricular Myosins ; metabolism

OBJECTIVETo investigate the role of miRNA-199a on cardiac hypertrophy.

METHODS(1) Male Sprague-Dawley rats were subjected to pressure overload induced by abdominal aortic constriction (AAC, n = 6) and quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the change of microRNAs (miRNAs). (2) Neonatal rat ventricular myocytes were isolated from 2-day old Sprague-Dawley rats. The myocytes were divided into two groups: adenovirus miRNA-199a (Ad-miRNA-199a) or adenovirus vector (Ad-vector). They were transfected in cardiomyocytes for 48 h using Lipofectamine 2000. qRT-PCR was used to detect the change of myocardial hypertrophy markers α-myosin heavy chain (αMHC, myh6), β-myosin heavy chain (βMHC, myh7) and atrial natriuretic peptide (ANP, Nppa). Software Axio Vision was used to detect the change of cardiomyocytes surface areas. (3) Neonatal rat ventricular myocytes were divided into two groups: antisense oligonucleotide-miRNA-199a (As-miRNA-199a) and scramble oligonucleotides (As-ctl). They were transfected to cardiomyocytes respectively for 48 h. qRT-PCR was used to detect the change of miRNA-199a. (4) Neonatal rat ventricular myocytes were divided into four groups: A: control (ctl), B: phenylephrine (PE), C: PE + As-ctl, D: PE + As-miRNA-199a. qRT-PCR was used to detect the change of myh6, myh7 and Nppa. Software Axio Vision was used to detect the change of cardiomyocytes surface areas.

RESULTS(1) qRT-PCR results showed that miRNA-1, miRNA-133, miRNA-181a and miRNA-499 were significantly decreased, while the miRNA-199a was significantly increased at 1 week post AAC hearts compared with the sham group. (2) qRT-PCR results showed that miRNA-199a and myh7 were increased and myh6 was decreased significantly in Ad-miRNA-199a group compared with Ad-vector group. The cardiomyocytes surface area was increased in Ad-miRNA-199a group detected by immunofluorescence. (3) qRT-PCR results showed that miRNA-199a was significantly decreased in As-miRNA-199a group compared with Ad-vector group. (4) The Nppa and myh7 were significantly increased and myh6 was decreased in cardiomyocytes stimulated by PE for 48 h. The cardiomyocytes surface area determined by immunofluorescence was increased in PE + As-miRNA-199a groups compared with PE + As-ctl groups.

CONCLUSIONmiRNA-199a may play a regulatory role in cardiac hypertrophy.

Animals ; Animals, Newborn ; Atrial Natriuretic Factor ; metabolism ; Cardiomegaly ; metabolism ; pathology ; Male ; MicroRNAs ; Myosin Heavy Chains ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

In order to improve the expression of recombinant human atrial natriuretic peptide (ANP), a new plasmid (pET28a(+)/ANP₃) containing 3 tandem ANP genes with lysine codon as the interval linker, was constructed. Target gene was transformed into Escherichia coli BL21 (DE3) and induced by IPTG, about 60% of the total-cell-protein was the target protein, His₆-ANP₃. After denaturation and refolding, it was digested by Endoproteinase Lys-C and Carboxypeptidase B (CPB) and then purified by a series of purification processes, about 16 mg purified ANP monomer could be obtained from one liter bacteria broth of shaking culture. Ultimately, the purity of protein was above 90% determined by UPLC and Tricine SDS-PAGE, its molecular weight was 3 080 Da according to LC-MS identification and it was proved to be equivalent to the reference product by ELISA. The use of tandem gene expression can provide a new possible model for the expression of other peptide drugs.
Atrial Natriuretic Factor ; biosynthesis ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; metabolism ; Gene Expression ; Humans ; Metalloendopeptidases ; Peptides ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis

OBJECTIVETo construct the folic acid deficient model in zebrafish and observe the abnormal cardiac phenotypes, to find the optimal period for supplementing folic acid that can most effectively prevent the heart malformation induced by folic acid deficiency, and to investigate the possible mechanisms by which folic acid deficiency induces malformations of heart.

METHODThe folic acid deficient zebrafish model was constructed by using both the folic acid antagonist methotrexate (MTX) and knocking-down dhfr (dihydrofolate reductase gene). Exogenous tetrahydrofolic acid rescue experiment was performed. Folic acid was given to folic acid deficient groups in different periods. The percent of cardiac malformation, the cardiac phenotypes, the heart rate and the ventricular shortening fraction (VSF) were recorded. The out flow tract (OFT) was observed by using fluorescein micro-angiography. Whole-mount in situ hybridization and real-time PCR were performed to detect vmhc, amhc, tbx5 and nppa expressions.

RESULTAbout (78.00 ± 3.74)% embryos in MTX treated group and (68.00 ± 6.32)% embryos in dhfr knocking-down group had heart malformations, including the abnormal cardiac shapes, the hypogenesis of OFT and the reduced heart rate and VSF. Giving exogenous tetrahydrofolic acid rescued the above abnormalities. Given the folic acid on 8 - 12 hours post-fertilization (hpf), both the MTX treated group (20.20% ± 3.77%) and dhfr knocking-down group (43.40% ± 4.51%) showed the most significantly reduced percent of cardiac malformation and the most obviously improved cardiac development. In folic acid deficient group, the expressions of tbx5 and nppa were reduced while the expressions of vmhc and amhc appeared normal. After being given folic acid to MTX treated group and dhfr knocking-down group, the expressions of tbx5 and nppa were increased.

CONCLUSIONSThe synthesis of tetrahydrofolic acid was decreased in our folic acid deficient model. Giving folic acid in the middle period, which is the early developmental stage, can best prevent the abnormal developments of hearts induced by folic acid deficiency. Folic acid deficiency did not disrupt the differentiations of myosins in ventricle and atrium. The cardiac malformations caused by folic acid deficiency were related with the reduced expressions of tbx5 and nppa.

Animals ; Atrial Natriuretic Factor ; metabolism ; Cell Differentiation ; drug effects ; Folic Acid ; metabolism ; Folic Acid Deficiency ; genetics ; metabolism ; Gene Knockdown Techniques ; Heart ; drug effects ; embryology ; growth & development ; T-Box Domain Proteins ; metabolism ; Zebrafish ; embryology ; genetics

Hypertension and anemia may be causes of left ventricular hypertrophy (LVH) in uremia but the molecular mechanism is not known. Uremia was induced in male Spraugue Dawley rats by 5/6 nephrectomy. The following groups of rats were studied for 6 weeks; uremic rats (U) fed ad. lib., control rats (C) pair-fed with U, U rats given hydralazine (100 mg/kg/day) (UH), U rats given erythropoietin (48U/kg/week, i.p.) (UE). Both diastolic and mean arterial pressures are higher (P<0.01) in U and UE compared with C whereas both pressures in UH were normalized. Hemoglobin in U was lower than in C, and was normalized in UE. U, UH and UE had higher heart weight/body weight ratios (HW/BW) as well as left ventricular weight/body weight ratios (LV/BW) compared with C (P<0.01). Compared with U, UH has lower HW/BW and LV/BW (P <0.05) and UE has normal HW/BW but lower LV/BW than U (P<0.05). To see if the gene expression in uremic LVH is similar to that described in pressure overload LVH in which mRNA levels of angiotensin converting enzyme (ACE), transforming growth factor-beta1 (TGF-beta1), atrial natriuretic factors (ANF) and skeletal alpha-actin were increased, we measured these mRNA levels by Northern analysis. TGF-beta, ACE and alpha-actin mRNA levels were not changed in all 4 groups. ANF mRNA in U and UE was increased 3 fold over C, and normalized in UH. Treatment of anemia with erythropoietin improved uremic LVH but did not change ANF mRNA; whereas treatment of hypertension with hydralazine normalized ANF mRNA but did not completely correct uremic LVH. Thus, gene expression in uremic LVH is distinct from that in pressure- overload LVH, suggesting that other unidentified factor(s) might be involved in uremic LVH.
Actins/genetics/metabolism ; Anemia/*complications/drug therapy/metabolism ; Animals ; Atrial Natriuretic Factor/genetics/metabolism ; Erythropoietin/pharmacology/therapeutic use ; *Gene Expression ; Heart Ventricles/chemistry/drug effects/pathology ; Hydralazine/pharmacology/therapeutic use ; Hypertension/*complications/drug therapy/metabolism ; Hypertrophy, Left Ventricular/etiology/*genetics/metabolism ; Male ; Peptidyl-Dipeptidase A/genetics/metabolism ; RNA, Messenger/analysis/metabolism ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta/genetics/metabolism ; Uremia/etiology/*genetics/metabolism

OBJECTIVETo study the effect of Danshensu (DSS) and Ligustrazine (TMZ), the extracts of Chinese herbs for promoting blood circulation, on angiotensin II (Ang II) induced myocardial hypertrophy and its related genes, and to explore the mechanisms of inhibitory effect.

METHODSAdopting one-step method, the total RNA of myocardial cells was extracted by TRIzol reagent. Then the expression of ANP and beta-actin mRNA, as symbol of myocardial cells, were detected by RT-PCR.

RESULTSMolecular biological research showed that Ang II could significantly increase the expression of ANP mRNA in myocardial cells (P < 0.01), which could be significantly inhibited by Losartan (P < 0.01), both DSS and TMZ had the inhibitory effect (P < 0.05). Ang II could increase beta-actin mRNA expression in myocardial cells simultaneously, Losartan, DSS and TMZ could also significantly inhibit it (P < 0.05).

CONCLUSIONThe effective ingredients of Chinese herbs for promoting blood circulation, DSS and TMZ, have the effect of inhibiting the hyper-expression of ANP and beta-actin induced by Ang II, and preventing myocardial hypertrophy, therefore, it could be used to prevent and treat cardiomegaly.

Angiotensin II ; Animals ; Animals, Newborn ; Atrial Natriuretic Factor ; biosynthesis ; genetics ; Cardiomegaly ; chemically induced ; metabolism ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Female ; Lactates ; pharmacology ; Male ; Myocytes, Cardiac ; cytology ; metabolism ; Pyrazines ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Wistar

To investigate the potential of gene therapy for the treatment of chronic diseases such as hypertension, chronic heart failure, and chronic renal failure, we established the neonatal rat fibroblast line engineered to secrete the mutant human atrial natriuretic peptide (mhANP), and then transplanted the cell line into young spontaneously hypertensive rats (SHR) subcutaneously. We found that a single transplantation of the cell line caused an obvious rise in the concentration of mhANP in serum 7 d after transplantation ((135 +/- 8) vs (106 +/- 7) pg/mL, P < 0.01). The animals' blood pressure in test group was always remarkably lower than that of empty vector group within 42 d after transplantation, even though the blood pressure in all groups was constantly increasing in the process of ontogeny ((175 +/- 10) mm Hg vs (189 +/- 12) mm Hg, P < 0.05). A maximal blood pressure reduction of 33 mm Hg ((157 +/- 9) mm Hg vs (124 +/- 112) mm Hg, P < 0.01) was observed 14 d post cell transplantation. There was a marked increase in urine volume in test group from second week after treatment beginning ((5.9 +/- 0.7) mL/6 h vs (4.3 +/- 0.8) mL/6 h, P < 0.01) and the effect lasted 14 d ((6.1 +/- 1.1) mL/6 h vs (4.0 +/- 0.8) mL/6 h, P < 0.01), however the statistical difference in concentration of K+ and Na+ in serum and urine was not observed. The results suggested that subcutaneous implantation of fibroblasts-expressing mhANP significantly reduced blood pressure in young SHR during the period of ontogeny and efficiently improved their renal function and the somatic gene transfer of mhANP may have potential value in the treatment of human chronic diseases such as hypertension, chronic heart failure, and chronic renal failure.
Animals ; Atrial Natriuretic Factor ; genetics ; physiology ; Cell Line ; Fibroblasts ; cytology ; metabolism ; transplantation ; Gene Expression ; Genetic Therapy ; methods ; Humans ; Hypertension ; genetics ; physiopathology ; therapy ; Male ; Mutation ; Rats ; Rats, Inbred SHR ; Transfection ; Urination

The present study was aimed at investigating the regulation of atrial natriuretic peptide (ANP) system in association with either enhanced or attenuated activity of the renin-angiotensin system (RAS). The cardiac tissue mRNA and peptide levels of ANP were measured in rats with two-kidney, one clip (2K1C) or deoxycorticosterone acetate (DOCA)-salt hypertension. Plasma renin concentration was increased in 2K1C hypertension along with increases of renin mRNA and protein contents in the clipped kidney. On the contrary, it was suppressed in DOCA-salt hypertension along with decreases of renin mRNA and protein contents in the remaining kidney. The plasma ANP concentration was similarly increased in both models of hypertension. The cardiac tissue ANP contents were not significantly changed, but the tissue ANP mRNA levels were upregulated in the hypertrophied heart in these two models of hypertension. It is suggested that the cardiac ANP system is transcriptionally enhanced by cardiac hypertrophy associated with hypertension, independent of the systemic RAS.
Animal ; Atrial Natriuretic Factor/metabolism* ; Desoxycorticosterone ; Gene Expression Regulation ; Hypertension/metabolism* ; Hypertension/chemically induced ; Male ; Myocardium/pathology ; Organ Weight ; Peptides ; RNA, Messenger/analysis ; Rats ; Rats, Sprague-Dawley ; Renin/genetics* ; Renin/blood* ; Renin-Angiotensin System/physiology

AIMTo investigate the effects of pioglitazone on cardiac hypertrophy in vitro and in vivo.

METHODSAngiotensin II was used to establish hypertrophy of cardiac myocytes and pioglitazone was applied to these myocytes in various dosages in vitro. ANP and BNP mRNA expression was evaluated by RT-PCR, and the rate of protein synthesis in CM by 3H-leucine incorporation in cardiac myocytes. Left ventricular hypertrophy was induced by incomplete ligation of abdominal aorta of rats and pioglitazone (20 mg x kg(-1). day(-1)) was administrated one week prior to the operation until 4 weeks after the operation. Cytokines mRNA expression in left ventricle was measured by RT-PCR, left ventricular wall thickness and myocyte diameter were determined by pathological method.

RESULTSPioglitazone inhibited ANP and BNP mRNA expression and 3H-leucine incorporation in neonatal rat cardiac myocytes induced by angiotensin II in a dose-dependent manner in vitro. Furthermore, pioglitazone reduced the mRNA expression of proinflammatory cytokines, including interleukin-1 beta and cardiotrophin-1, and inhibited the pressure overload-induced increase in the ratio of heart weight to body weight, left ventricular wall thickness and myocyte diameter of rats in vivo.

CONCLUSIONPioglitazone inhibits cardiac hypertrophy of rats in vitro and in vivo, and may play a role in prevention and treatment of cardiovascular diseases characterized by cardiac hypertrophy in future.

Animals ; Atrial Natriuretic Factor ; metabolism ; Cardiomegaly ; metabolism ; pathology ; prevention & control ; Cell Line ; Cytokines ; metabolism ; Disease Models, Animal ; Interleukin-1beta ; metabolism ; Male ; Myocytes, Cardiac ; drug effects ; metabolism ; Natriuretic Peptide, Brain ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Thiazolidinediones ; pharmacology ; therapeutic use

OBJECTIVETo investigate the effects of evodiamine (Evo), a component of Evodiaminedia rutaecarpa (Juss.) Benth, on cardiomyocyte hypertrophy induced by angiotensin II (Ang II) and further explore the potential mechanisms.

METHODSCardiomyocytes from neonatal Sprague Dawley rats were isolated and characterized, and then the cadiomyocyte cultures were randomly divided into control, model (Ang II 0.1 μmol/L), and Evo (0.03, 0.3, 3 μmol/L) groups. The cardiomyocyte surface area, protein level, intracellular free calcium ([Ca]) concentration, activity of nitric oxide synthase (NOS) and content of nitric oxide (NO) were measured, respectively. The mRNA expressions of atrial natriuretic factor (ANF), calcineurin (CaN), extracellular signal-regulated kinase-2 (ERK-2), and endothelial nitric oxide synthase (eNOS) of cardiomyocytes were analyzed by real-time reverse transcriptionpolymerase chain reaction. The protein expressions of calcineurin catalytic subunit (CnA) and mitogen-activated protein kinase phosphatase-1 (MKP-1) were detected by Western blot analysis.

RESULTSCompared with the control group, Ang II induced cardiomyocytes hypertrophy, as evidenced by increased cardiomyocyte surface area, protein content, and ANF mRNA expression; increased intracellular free calcium ([Ca]) concentration and expressions of CaN mRNA, CnA protein, and ERK-2 mRNA, but decreased MKP-1 protein expression (P<0.05 or P<0.01). Compared with Ang II, Evo (0.3, 3 μmol/L) significantly attenuated Ang II-induced cardiomyocyte hypertrophy, decreased the [Ca] concentration and expressions of CaN mRNA, CnA protein, and ERK-2 mRNA, but increased MKP-1 protein expression (P<0.05 or P<0.01). Most interestingly, Evo increased the NOS activity and NO production, and upregulated the eNOS mRNA expression (P<0.05).

CONCLUSIONEvo signifificantly attenuated Ang II-induced cardiomyocyte hypertrophy, and this effect was partly due to promotion of NO production, reduction of [Ca]i concentration, and inhibition of CaN and ERK-2 signal transduction pathways.

Angiotensin II ; Animals ; Atrial Natriuretic Factor ; metabolism ; Calcineurin ; genetics ; metabolism ; Calcium ; metabolism ; Dual Specificity Phosphatase 1 ; genetics ; metabolism ; Extracellular Signal-Regulated MAP Kinases ; genetics ; metabolism ; Hypertrophy ; Myocytes, Cardiac ; drug effects ; metabolism ; pathology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Quinazolines ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Rats, Sprague-Dawley