Suppression of the Inhibitory Effect of circ_0036176-Translated Myo9a-208 on Cardiac Fibroblast Proliferation by miR-218-5p

Increasing evidence has shown that circular RNAs (circRNAs) participate in the process of cardiac remodeling. CircRNA circ_0036176 originating from the back-splicing of exon 2 to exon4 of myosin IXA (Myo9a) gene was shown to be increased in the myocardium of patients with heart failure (HF) and riched in exosomes from human AC16 cardiomyocytes with overexpression of circ_0036176. Proliferation activity was inhibited in mCFs subjected to exosomal circ_0036176 treatment and in mCFs with overexpression of circ_0036176. Interestingly, circ_0036176 contains an IRES element and an ORF of 627 nt encoding a 208-amino acid protein (termed as Myo9a-208). Myo9a-208 was shown to mediate the inhibitory effect of circ_0036176 on CFs proliferation, and miR-218-5p could inhibit Myo9a-208 expression by binding to circ_0036176, resulting in abolishing the effect of circ_0036176 on inactivating cyclin/Rb signal and suppressing CFs proliferation. Our findings suggest that circ_0036176 inhibits mCFs proliferation by translating Myo9a-208 protein to suppress cyclin/Rb pathway.

Diverging targets mediate the pathological roleof miR-199a-5p and miR-199a-3p by promoting cardiac hypertrophy and fibrosis

MicroRNA-199a-5p (miR-199a-5p) and -3p are enriched in the myocardium, but it is unknown whether miR-199a-5p and -3p are co-expressed in cardiac remodeling and what roles they have in cardiac hypertrophy and fibrosis. We show that miR-199a-5p and -3p are co-upregulated in the mouse and human myocardium with cardiac remodeling and in Ang-II-treated neonatal mouse ventricular cardiomyocytes (NMVCs) and cardiac fibroblasts (CFs). miR-199a-5p and -3p could aggravate cardiac hypertrophy and fibrosis in vivo and in vitro. PPAR gamma coactivator 1 alpha (Ppargc1a) and sirtuin 1 (Sirt1) were identified as target genes to mediate miR-199a-5p in promoting both cardiac hypertrophy and fibrosis. However, miR-199a-3p aggravated cardiac hypertrophy and fibrosis through targeting RB transcriptional corepressor 1 (Rb1) and Smad1, respectively. Serum response factor and nuclear factor κB p65 participated in the upregulation of miR-199a-5p and -3p in Ang-II-treated NMVCs and mouse CFs, and could be conversely elevated by miR-199a-5p and -3p. Together, Ppargc1a and Sirt1, Rb1 and Smad1 mediated the pathological effect of miR-199a-5p and -3p by promoting cardiac hypertrophy and fibrosis, respectively. This study suggests a possible new strategy for cardiac remodeling therapy by inhibiting miR-199a-5p and -3p.

Dickkopf 3: a Novel Target Gene of miR-25-3p in Promoting Fibrosis-Related Gene Expression in Myocardial Fibrosis

Increasing evidence has shown that microRNAs (miRNAs) participate in cardiac fibrosis. We aimed to elucidate the effect of miRNA miR-25-3p on cardiac fibrosis. MiRNA microarray was used to profile miRNAs in the myocardium of angiotensin-II (Ang-II)-infused mice. Effect of miR-25-3p on expression of fibrosis-related genes, including Col1a1, Col3a1, and Acta2, was investigated both in vitro and in vivo. MiR-25-3p was shown increased in the myocardium of Ang-II-infused mice and patients with heart failure. MiR-25-3p enhanced fibrosis-related gene expression in mouse cardiac fibroblasts (mCFs) and in the myocardium of Ang-II-infused mice. Dickkopf 3 (Dkk3) was identified as a target gene of miR-25-3p, and Dkk3 could ameliorate Smad3 activation and fibrosis-related gene expression via enhancing Smad7 expression in mCFs. Additionally, NF-κB signal was proven to mediate upregulation of miR-25-3p in cardiac fibrosis. Our findings suggest that miR-25-3p enhances cardiac fibrosis by suppressing Dkk3 to activate Smad3 and fibrosis-related gene expression.

Circular RNA circRNA_000203 aggravates cardiac hypertrophy via suppressing miR-26b-5p and miR-140-3p binding to Gata4

Aims

Circular RNAs (circRNAs) are involved in gene regulation in a variety of physiological and pathological processes. The present study aimed to investigate the effect of circRNA_000203 on cardiac hypertrophy and the potential mechanisms involved.

Methods and results

CircRNA_000203 was found to be up-regulated in the myocardium of Ang-II-infused mice and in the cytoplasma of Ang-II-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Enforced expression of circRNA_000203 enhances cell size and expression of atrial natriuretic peptide and β-myosin heavy chain in NMVCs. In vivo, heart function was impaired and cardiac hypertrophy was aggravated in Ang-II-infused myocardium-specific circRNA_000203 transgenic mice (Tg-circ203). Mechanistically, we found that circRNA_000203 could specifically sponge miR-26b-5p, -140-3p in NMVCs. Further, dual-luciferase reporter assay showed that miR-26b-5p, -140-3p could interact with 3′-UTRs of Gata4 gene, and circRNA_000203 could block the above interactions. In addition, Gata4 expression is transcriptionally inhibited by miR-26b-5p, -140-3p mimic in NMVCs but enhanced by over-expression of circRNA_000203 in vitro and in vivo. Functionally, miR-26b-5p, -140-3p, and Gata4 siRNA, could reverse the hypertrophic growth in Ang-II-induced NMVCs, as well as eliminate the pro-hypertrophic effect of circRNA_000203 in NMVCs. Furthermore, we demonstrated that NF-κB signalling mediates the up-regulation of circRNA_000203 in NMVCs exposed to Ang-II treatment.

Conclusions

Our data demonstrated that circRNA_000203 exacerbates cardiac hypertrophy via suppressing miR-26b-5p and miR-140-3p leading to enhanced Gata4 levels.

Targeting EZH1 and EZH2 contributes to the suppression of fibrosis-associated genes by miR-214-3p in cardiac myofibroblasts

The role of microRNA-214-3p (miR-214-3p) in cardiac fibrosis was not well illustrated. The present study aimed to investigate the expression and potential target of miR-214-3p in angiotensin II (Ang-II)-induced cardiac fibrosis. MiR-214-3p was markedly decreased in the fibrotic myocardium of a mouse Ang-II infusion model, but was upregulated in Ang-II-treated mouse myofibroblasts. Cardiac fibrosis was shown attenuated in Ang-II-infused mice received tail vein injection of miR-214-3p agomir. Consistently, miR-214-3p inhibited the expression of Col1a1 and Col3a1 in mouse myofibroblasts in vitro. MiR-214-3p could bind the 3'-UTRs of enhancer of zeste homolog 1 (EZH1) and -2, and suppressed EZH1 and -2 expressions at the transcriptional level. Functionally, miR-214-3p mimic, in parallel to EZH1 siRNA and EZH2 siRNA, could enhance peroxisome proliferator-activated receptor-γ (PPAR-γ) expression and inhibited the expression of Col1a1 and Col3a1 in myofibroblasts. In addition, enforced expression of EZH1 and -2, and knockdown of PPAR-γ resulted in the increase of Col1a1 and Col3a1 in myofibroblasts. Moreover, the NF-κB signal pathway was verified to mediate Ang-II-induced miR-214-3p expression in myofibroblasts. Taken together, our results revealed that EZH1 and -2 were novel targets of miR-214-3p, and miR-214-3p might be one potential miRNA for the prevention of cardiac fibrosis.

Targeting myocyte-specific enhancer factor 2D contributes to the suppression of cardiac hypertrophic growth by miR-92b-3p in mice

The role of microRNA-92b-3p (miR-92b-3p) in cardiac hypertrophy was not well illustrated. The present study aimed to investigate the expression and potential target of miR-92b-3p in angiotensin II (Ang-II)-induced mouse cardiac hypertrophy. MiR-92b-3p was markedly decreased in the myocardium of Ang-II-infused mice and of patients with cardiac hypertrophy. However, miR-92b-3p expression was revealed increased in Ang-II-induced neonatal mouse cardiomyocytes. Cardiac hypertrophy was shown attenuated in Ang-II-infused mice received tail vein injection of miR-92b-3p mimic. Moreover, miR-92b-3p inhibited the expression of atrial natriuretic peptide (ANP), skeletal muscle α-actin (ACTA1) and β-myosin heavy chain (MHC) in Ang-II-induced mouse cardiomyocytes in vitro. Myocyte-specific enhancer factor 2D (MEF2D), which was increased in Ang-II-induced mouse hypertrophic myocardium and cardiomyocytes, was identified as a target gene of miR-92b-3p. Functionally, miR-92b-3p mimic, consistent with MEF2D siRNA, inhibited cell size increase and protein expression of ANP, ACTA1 and β-MHC in Ang-II-treated mouse cardiomyocytes. Taken together, we demonstrated that MEF2D is a novel target of miR-92b-3p, and attenuation of miR-92b-3p expression may contribute to the increase of MEF2D in cardiac hypertrophy.

Role of tumour necrosis factor-a in the regulation of T-type calcium channel current in HL-1 cells

Increasing evidence indicates that inflammation contributes to the initiation and perpetuation of atrial fibrillation (AF). Although tumour necrosis factor (TNF)-α levels are increased in patients with AF, the role of TNF-α in the pathogenesis of AF remains unclear. Besides L-type Ca(2+) currents (IC a,L ), T-type Ca(2+) currents (IC a,T ) also plays an important role in the pathogenesis of AF. This study was designed to use the whole-cell voltage-clamp technique and biochemical assays to explore if TNF-α is involved in the pathogenesis of AF through regulating IC a,T in atrial myocytes. It was found that compared with sinus rhythm (SR) controls, T-type calcium channel (TCC) subunit mRNA levels were decreased, while TNF-α expression levels were increased, in human atrial tissue from patients with AF. In murine atrial myocyte HL-1 cells, after culturing for 24 h, 12.5, 25 and 50 ng/mL TNF-α significantly reduced the protein expression levels of the TCC α1G subunit in a concentration-dependent manner. The peak current was reduced by the application of 12.5 or 25 ng/mL TNF-α in a concentration-dependent manner (from -15.08 ± 1.11 pA/pF in controls to -11.89 ± 0.83 pA/pF and -8.54 ± 1.55 pA/pF in 12.5 or 25 ng/mL TNF-α group respectively). TNF-α application also inhibited voltage-dependent inactivation of IC a,T, shifted the inactivation curve to the left. These results suggest that TNF-α is involved in the pathogenesis of AF, probably via decreasing IC a,T current density in atrium-derived myocytes through impaired channel function and down-regulation of channel protein expression. This pathway thus represents a potential pathogenic mechanism in AF.

[Retrospect of Chinese herbs taken as tea drinking]

Tea and wine are time-honored drinks in China. Along with coffee and cocoa, tea, as one of the non-alcoholic plant beverages, is prevailing the world. Tea and Chinese medicine has a very close relationship. Chinese herbs taken as tea forming the tea-like medicinal tea, can be taken frequently at anytime. The application of Chinese herbs taken as tea drinking begins from the Tang Dynasty, flourishes in the Song Dynasty and matures in the Qing Dynasty. The review of its history provides ample evidence of Chinese herbs taken as tea drinking in treating and preventing diseases, as well as providing the clues and references of developing new Chinese herbs taking as tea.

Species-specific differences in the role of L-type Ca²⁺ channels in the regulation of coronary arterial smooth muscle contraction

The L-type calcium channel (LCC) plays a regulatory role in various physical and pathological processes. In the vasculature, LCCs mediate agonist-induced vascular smooth muscle contraction. However, whether LCC-mediated vessel responses to certain vasoconstrictors vary among species remains unclear. The coronary arteries were dissected from the hearts of rats and mice. Coronary arterial ring contraction was measured using the Multi Myograph system. High K+ (60 mM)-induced coronary artery contractions were stronger in rats than in mice, whereas CaCl2-induced contraction curves did not differ significantly between the two groups. Endothelin-1, U46619 (thromboxane A2 receptor agonist), and 5-hydroxytryptamine (5-HT) induced concentration-dependent vasoconstriction of coronary arterial rings in rats and mice. The vessel rings of mice were more sensitive to ET-1 and U46619 and less sensitive to 5-HT than those of rats. The LCC blocker nifedipine significantly inhibited coronary artery contractions induced by ET-1, U46619, and 5-HT. The inhibitory effect of 1 μM nifedipine on ET-1- and 5-HT-induced coronary artery contractions was stronger in mice than in rats, whereas its effect on U46619-induced vessel contractions was weaker in mice than in rats. The 5-HT2A receptor and LCC mRNA levels were higher in the coronary arteries of rats than in those of mice, whereas the expressions of the ETA and TXA2 receptors and Orai1 mRNA levels were comparable between the two groups. LCC plays an important role in coronary arterial contraction. Rats and mice show different responses to vasoconstrictors and LCC blockers, suggesting that the coronary arteries of rats and mice have different biological characteristics.

Left ventricular deformation associated with cardiomyocyte Ca(2+) transients delay in early stage of low-dose of STZ and high-fat diet induced type 2 diabetic rats

Background

In the early stage of diabetes, the cardiac ejection fraction is preserved, despite the existence of the subclinical cardiac dysfunction to some extent. However, the detailed phenotype of this dysfunction and the underlying mechanism remain unclear. To improve our understanding of this issue, we used low-dose STZ and high-fat diet to induce type 2 diabetic models in rats. The effects and the mechanism associated with the early stages of the disease were analyzed.

Methods

The type 2 diabetic mellitus (T2DM) in SD rats were induced through 30 mg/kg STZ and high-fat diet. Two-dimensional spackle-tracking echocardiography (STE) and the dobutamine test were performed to examine the cardiac function. Calcium transients of left ventricular myocytes were detected and the related intracellular signalling factors were analyzed by western blotting.

Results

After 6-weeks, T2DM rats in left ventricular (LV) diastole showed decreased global and segment strain(S) levels (P < 0.05), both in the radial and circumferential directions. Strain rate (Sr) abatement occurred in three segments in the radial and circumferential directions (P < 0.05), and the radial global Sr also decreased (P < 0.05). In the systolic LV, radial Sr was reduced, except the segment of the anterior septum, and the Sr of the lateral wall and post septum decreased in the circumferential direction (P < 0.05). Conventional M-mode echocardiography failed to detect significant alterations of cardiac performance between the two groups even after 12 weeks, and the decreased ejection fraction (EF%), fractional shortening (FS%) and end-systolic diameters (ESD) could be detected only under stress conditions induced by dobutamine (P < 0.05). In terms of calcium transients in cardiac myocytes, the T_peak in model rats at 6 weeks was not affected, while the T_decay1/2 was higher than that of the controls (P < 0.05), and both showed a dose-dependent delay after isoproterenol treatment (P < 0.05). Western blot analysis showed that in 6-week T2DM rats, myocardial p-PLB expression was elevated, whereas p-CaMKII, p-AMPK and Sirt1 were significantly down-regulated (P < 0.05).

Conclusion

A rat model of T2DM was established by low dose STZ and a high-fat diet. LV deformation was observed in the early stages of T2DM in association with the delay of Ca²⁺ transients in cardiomyocytes due to the decreased phosphorylation of CaMKII. Myocardial metabolism remodeling might contribute to the early LV function and calcium transportation abnormalities.

Attenuation of microRNA-16 derepresses the cyclins D1, D2 and E1 to provoke cardiomyocyte hypertrophy

Cyclins/retinoblastoma protein (pRb) pathway participates in cardiomyocyte hypertrophy. MicroRNAs (miRNAs), the endogenous small non-coding RNAs, were recognized to play significant roles in cardiac hypertrophy. But, it remains unknown whether cyclin/Rb pathway is modulated by miRNAs during cardiac hypertrophy. This study investigates the potential role of microRNA-16 (miR-16) in modulating cyclin/Rb pathway during cardiomyocyte hypertrophy. An animal model of hypertrophy was established in a rat with abdominal aortic constriction (AAC), and in a mouse with transverse aortic constriction (TAC) and in a mouse with subcutaneous injection of phenylephrine (PE) respectively. In addition, a cell model of hypertrophy was also achieved based on PE-promoted neonatal rat ventricular cardiomyocyte and based on Ang-II-induced neonatal mouse ventricular cardiomyocyte respectively. We demonstrated that miR-16 expression was markedly decreased in hypertrophic myocardium and hypertrophic cardiomyocytes in rats and mice. Overexpression of miR-16 suppressed rat cardiac hypertrophy and hypertrophic phenotype of cultured cardiomyocytes, and inhibition of miR-16 induced a hypertrophic phenotype in cardiomyocytes. Expressions of cyclins D1, D2 and E1, and the phosphorylated pRb were increased in hypertrophic myocardium and hypertrophic cardiomyocytes, but could be reversed by enforced expression of miR-16. Cyclins D1, D2 and E1, not pRb, were further validated to be modulated post-transcriptionally by miR-16. In addition, the signal transducer and activator of transcription-3 and c-Myc were activated during myocardial hypertrophy, and inhibitions of them prevented miR-16 attenuation. Therefore, attenuation of miR-16 provoke cardiomyocyte hypertrophy via derepressing the cyclins D1, D2 and E1, and activating cyclin/Rb pathway, revealing that miR-16 might be a target to manage cardiac hypertrophy.

Involvement of Src tyrosine kinase and protein kinase C in the expression of macrophage migration inhibitory factor induced by H2O2 in HL-1 mouse cardiac muscle cells

Macrophage migration inhibitory factor (MIF), a pleiotropic cytokine, plays an important role in the pathogenesis of atrial fibrillation; however, the upstream regulation of MIF in atrial myocytes remains unclear. In the present study, we investigated whether and how MIF is regulated in response to the renin-angiotensin system and oxidative stress in atrium myocytes (HL-1 cells). MIF protein and mRNA levels in HL-1 cells were assayed using immunofluorescence, real-time PCR, and Western blot. The result indicated that MIF was expressed in the cytoplasm of HL-1 cells. Hydrogen peroxide (H₂O₂), but not angiotensin II, stimulated MIF expression in HL-1 cells. H₂O₂-induced MIF protein and gene levels increased in a dose-dependent manner and were completely abolished in the presence of catalase. H₂O₂-induced MIF production was completely inhibited by tyrosine kinase inhibitors genistein and PP1, as well as by protein kinase C (PKC) inhibitor GF109203X, suggesting that redox-sensitive MIF production is mediated through tyrosine kinase and PKC-dependent mechanisms in HL-1 cells. These results suggest that MIF is upregulated by HL-1 cells in response to redox stress, probably by the activation of Src and PKC.

MicroRNA 16 enhances differentiation of human bone marrow mesenchymal stem cells in a cardiac niche toward myogenic phenotypes in vitro

AIM

Upregulation of microRNA 16 (miR-16) contributed to the differentiation of human bone marrow mesenchymal stem cells (hMSCs) toward myogenic phenotypes in a cardiac niche, the present study aimed to determine the role of miR-16 in this process.

MAIN METHODS

hMSCs and neonatal rat ventricular myocytes were co-cultured indirectly in two chambers to set up a cardiac microenvironment (niche). miRNA expression profile in cardiac-niche-induced hMSCs was detected by miRNA microarray. Cardiac marker expression and cell cycle analysis were determined in different treatment hMSCs. Quantitative real-time PCR and Western blot were used to identify the expression of mRNA, mature miRNA and protein of interest.

KEY FINDINGS

miRNA dysregulation was shown in hMSCs after cardiac niche induction. miR-16 was upregulated in cardiac-niche-induced hMSCs. Overexpression of miR-16 significantly increased G1-phase arrest of the cell cycle in hMSCs and enhanced the expression of cardiac marker genes, including GATA4, NK2-5, MEF2C and TNNI3. Differentiation-inducing factor 3 (DIF-3), a G0/G1 cell cycle arrest compound, was used to induce G1 phase arrest in cardiac-niche-induced hMSCs, and the expression of cardiac marker genes was up-regulated in DIF-3-treated hMSCs. The expression of CCND1, CCND2 and CDK6 was suppressed by miR-16 in hMSCs. CDK6, CCND1 or CCND2 knockdown resulted in G1 phase arrest in hMSCs and upregulation of cardiac marker gene expression in hMSCs in a cardiac niche.

SIGNIFICANCE

miR-16 enhances G1 phase arrest in hMSCs, contributing to the differentiation of hMSCs toward myogenic phenotypes when in a cardiac niche. This mechanism provides a novel strategy for pre-modification of hMSCs before hMSC-based transplantation therapy for severe heart diseases.

Induced bone marrow mesenchymal stem cells improve cardiac performance of infarcted rat hearts

We investigated whether transplantation of bone marrow mesenchymal stem cells (BMSC) with induced BMSC (iBMSC) or uninduced BMSC (uBMSC) into the myocardium could improve the performance of post-infarcted rat hearts. BMSCs were specified by flowcytometry. IBMSCs were cocultured with rat cardiomyocyte before transplantation. Cells were injected into borders of cardiac scar tissue 1 week after experimental infarction. Cardiac performance was evaluated by echocardiography at 1, 2, and 4 weeks after cellular or PBS injection. Langendorff working-heart and histological studies were performed 4 weeks after treatment. Myogenesis was detected by quantitative PCR and immunofluorescence. Echocardiography showed a nearly normal ejection fraction (EF) in iBMSC-treated rats and all sham control rats but a lower EF in all PBS-treated animals. The iBMSC-treated heart, assessed by echocardiography, improved fractional shortening compared with PBS-treated hearts. The coronary flow (CF) was decreased obviously in PBS and uBMSC-treated groups, but recovered in iBMSC-treated heart at 4 weeks (P < 0.01). Immunofluorescent microscopy revealed co-localization of Superparamagnetic iron oxide (SPIO)-labeled transplanted cells with cardiac markers for cardiomyocytes, indicating regeneration of damaged myocardium. These data provide strong evidence that iBMSC implantation is of more potential to improve infarcted cardiac performance than uBMSC treatment. It will open new promising therapeutic opportunities for patients with post-infarction heart failure.

Effect of impaired glucose tolerance on cardiac dysfunction in a rat model of prediabetes

BACKGROUND

The effect of impaired glucose tolerance (IGT) on cardiac function during the chronic prediabetes state is complicated and plays an important role in clinical outcome. However, the molecular mechanisms are not fully understood. This study was designed to observe cardiac dysfunction in prediabetic rats with IGT and to determine whether glucose metabolic abnormalities, inflammation and apoptosis are linked to it.

METHODS

The IGT rat models were induced by streptozocin, and the heart functions were assessed by echocardiography. Myocardial glucose metabolism was analyzed by glycogen periodic acid-Schiff staining, and the pro-apoptotic effect of IGT was evaluated by TUNEL staining. Additionally, caspase-3 activation, macrophage migration inhibitory factor (MIF) and G-protein coupled receptor kinase 2 (GRK2) were detected by Western blotting in cardiac tissue lysates.

RESULTS

Area-under-the-curve of blood glucose in rats injected with streptozotocin was higher than that in controls, increased by 16.28%, 38.60% and 38.61% at 2, 4 and 6 weeks respectively (F = 15.370, P = 0.003). Abnormal cardiac functions and apoptotic cardiomyocytes were observed in the IGT rats, the ejection fraction (EF) being (68.59 ± 6.62)% in IGT rats vs. (81.07 ± 4.59)% in controls (t = 4.020, P = 0.002). There was more glucose which was converted to glycogen in the myocardial tissues of IGT rats, especially in cardiac perivascular tissues. Compared to controls, the cleaved caspase-3, MIF and GRK2 were expressed at higher levels in the myocardial tissues of IGT rats.

CONCLUSIONS

IGT in the prediabetes period resulted in cardiac dysfunction linked to abnormal glycogen storage and apoptosis. Additionally, MIF and GRK2 may be involved in the pathogenesis of cardiac dysfunction in prediabetes and their regulation may contribute to the design of novel diagnostic and therapeutic strategies for those who have potential risks for diabetic cardiovascular complications.

Transcription factor Ap-1 mediates proangiogenic MIF expression in human endothelial cells exposed to Angiotensin II

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine associated with the atherosclerotic process and atherosclerotic plaque stability. MIF was shown to be highly expressed in advanced atherosclerotic lesions. Neutralizing MIF with a blocking antibody induced a regression of established atherosclerotic lesions. In this study, we investigated the mechanism underlying the proangiogenic effect of MIF in human umbilical vein endothelial cells (HUVECs). We showed that MIF induced the expression of angiogenesis-related genes in HUVECs. We also showed that MIF induced tube formation of HUVECs in vitro and in vivo. Angiotensin II (Ang II) could specifically up-regulate MIF expression in HUVECs. Using a luciferase reporter assay, we demonstrated that the AP-1 response element in the 5'-UTR of the MIF gene played a role in Ang II-induced MIF expression. Small hairpin RNA (shRNA) targeting c-Jun, a component of AP-1, and the AP-1 inhibitor CHX both efficiently inhibited MIF expression. The consistent result of electrophoretic mobility shift assay (EMSA) showed that Ang II specifically increased AP-1 activation in HUVECs. Our results suggest that AP-1 mediates Ang II-induced MIF expression which contributes to atherosclerotic plaque destabilization in human endothelial cells.

miR-1/miR-206 regulate Hsp60 expression contributing to glucose-mediated apoptosis in cardiomyocytes

Hsp60 is an important component of defense mechanisms against diabetic myocardial injury; however, the cause of Hsp60 reduction in the diabetic myocardium remains unknown. After stimulation of cardiomyocytes with high glucose in vivo and in vitro, significant up-regulation of miR-1/miR-206 and post-transcriptional modulation of Hsp 60 were observed. Serum response factor (SRF) and the MEK1/2 pathway were involved in miR-1 and miR-206 expression in cardiomyocytes. miR-1 and miR-206 regulated Hsp60 expression post-transcriptionally and accelerated cardiomyocyte apoptosis through Hsp60. These results revealed that miR-1 and miR-206 regulate Hsp60 expression, contributing to high glucose-mediated apoptosis in cardiomyocytes.

Comparison of approaches for efficient gene silencing induced by microRNA-based short hairpin RNA and indicator gene expression

MicroRNA-based short hairpin RNAs (shRNAs) are natural inducers of RNA interference and have been increasingly used in shRNA expression strategies. In the present study, we compared the efficiencies of exogenous green fluorescence protein (GFP) and endogenous glyceraldehyde-3-phosphate dehydrogenase (GAPDH) knockdown and red fluorescent protein (RFP) indicator expression mediated by three differently designed plasmids. RFP was introduced either at the 5' end, at the 3' end of the human mir155-based target gene (TG) (e.g., GFP or GAPDH) shRNA expression cassette (EC), or at the 3' end of the chimeric intron-containing TG shRNA EC. Comparisons with the control vector showed an obvious reduction of GFP or GAPDH expression with the various shRNA expression plasmids (P < 0.05). When RFP was located at the 5' end or at the 3' end of the TG shRNA EC, RFP expression was low; whereas when RFP was connected with the chimeric intron-containing TG shRNA EC, RFP expression was high. Taken together, this study demonstrated an efficient plasmid design for both TG silencing induced by microRNA-based shRNA and indicator gene expression in vitro.

Upregulated expression of miR-1/miR-206 in a rat model of myocardial infarction

MicroRNAs (miRNAs) have been increasingly reported to have important roles in diverse biological and pathological processes. We investigated miR-1 and miR-206 expression and their potential roles in a rat model of myocardial infarction (MI). miR-1 and miR-206 expression were significantly increased, and insulin-like growth factor 1 (IGF-1) protein was markedly reduced without obvious change of its mRNA level after MI induction. Position 175-196 of rat IGF-1 3'-untranslated region was identified to be required for efficient downregulation by miR-1/miR-206. IGF-1 level was reduced without changing its transcript level in rat H9C2 myoblast cells modified with miR-1 (H9C2-miR-1). In the serum withdrawal and hypoxic condition, caspase-3 activity and mitochondrial potential were significantly increased in H9C2-miR-1 cells compared with the control group, respectively (p<0.05, p<0.01). Together, our results indicate that miR-1 and miR-206 are involved in apoptotic cell death in MI by post-transcriptional repression of IGF-1.

[Reinforcing qi and promoting blood circulation to prevent hepatic fibrosis due to bovine serum albumin immunologic injury]

44 Wistar female rats were divided randomly into 4 groups--normal control(I), case control (II), reinforcing Qi and promoting blood circulation(III) and nourishing Yin and promoting blood circulation(IV). After 4 times of bovine serum albumin (BSA) shock injection, the group III and the group IV were medicated through gastric intubation for 40 days respectively with 300% mixture of reinforcing Qi and promoting blood circulation and 300% mixture of nourishing Yin and promoting blood circulation. The results suggest the mixture of reinforcing Qi and promoting blood circulation has the function of alleviating pathological changes of liver, reducing the content of liver collagen, improving erythrocytic function of clearing away immune complexes and regulating humoral immune response.

Endovesical instillation of mitomycin-C in preventing recurrence of superficial bladder carcinoma

It is now clear that MMC can be used as endovesical instillation after TUR, partial cystectomy or transurethral laser treatment and at the same time it has chemo-resection and chemoprophylactic efficacy. The success of treatment seems out of question on dosage but with the continuation of the instillation program. Recently, we have adopted 20 mg per instillation once every week for 40 times in the first year and once for 2-4 weeks for the second year, the overall recurrent rate was 17%. Such dosage used is more better than 2 mg, 10 mg or even 40 mg with acceptable side effects.