Impact of Pax-8 gene interference on mitochondrial function and cardiomyocyte apoptosis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the effects of paired box gene 8 (Pax-8) silencing by RNA interference on mitochondrial function and cardiomyocytes apoptosis.</p><p><b>METHODS</b>The cultured H9C2 (2-1) myocytes were divided into 3 groups: short interference RNA targeting Pax-8 (Pax-8 siRNA) group, non-specific siRNA group as the negative control (NC siRNA), and blank control group (BC siRNA). Fluorescence spectrophotometry was used to detect the activity of caspase-3. RT-PCR was performed to detect mRNA expression of Bcl2 and Bax. The protein expression of Bcl2, Bax and cytoplasm of Cytochrome was examined by Western blot. Changes of ΔΨm were detected by flow cytometry.ΔΨm with JC-1 monomer/polymer ratio was calculated for measuring mitochondrial depolarization proportion.</p><p><b>RESULTS</b>Compared to NC siRNA and BC siRNA group (0.075 ± 0.021, 0.072 ± 0.019), the activity of caspase-3 in Pax-8 siRNA group (0.167 ± 0.012) was significantly increased (P < 0.05); Bcl2 mRNA and protein expression in Pax-8 siRNA group (0.61 ± 0.06, 0.94 ± 0.11) were significantly downregulated compared with NC siRNA group (0.90 ± 0.070, 1.39 ± 0.15) and BC siRNA group (0.94 ± 0.087, 1.49 ± 0.20) (P < 0.05); Bax mRNA and protein expression in Pax-8 siRNA group (1.05 ± 0.10, 1.25 ± 0.12) were markedly upregulated compared with NC siRNA group (0.72 ± 0.03, 0.99 ± 0.12) and BC siRNA group (0.64 ± 0.03, 0.92 ± 0.06), P < 0.05; cytosolic cytochrome expression in Pax-8 siRNA group (0.75 ± 0.14) was significantly upregulated compared with NC siRNA group (0.51 ± 0.06) and BC siRNA group (0.48 ± 0.07) (P < 0.05); JC-1 monomer/polymer ratio in Pax-8 siRNA group (0.163 ± 0.011) was significantly increased compared with NC siRNA group (0.092 ± 0.015) and BC siRNA group (0.072 ± 0.025) (P < 0.05) indicating mitochondrial membrane potential was significantly reduced in Pax-8 siRNA group. Above parameters were similar between NC siRNA group and BC siRNA group (P > 0.05).</p><p><b>CONCLUSION</b>Inhibiting Pax-8 results in enhanced cardiomyocytes apoptosis through the mitochondrial pathway.</p>

MicroRNA-144 over-expression induced myocytes apoptosis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of microRNA-144 (miR-144) expression on H9C2 (2-1) myocytes.</p><p><b>METHODS</b>MiR-144 was up-regulated in primary cultured H9C2 (2-1) myocytes through transfection. Cells transfected with Lipofectamine(TM) 2000 and its mixture with miRNA synthesized randomly as blank control and negative control respectively. The up-regulation of miR-144 was confirmed by real-time PCR. Cell apoptosis was evaluated by means of CCK-8, Caspase-3 and flow cytometry.</p><p><b>RESULTS</b>Real-time PCR results showed that the miR-144 expression was obviously increased in miR-144 up-regulation group (2178.84 ± 838.52) compared with negative (2.06 ± 0.73) and blank (1.00 ± 0.00) control group (all P < 0.01). The proliferation was lower, the activity of Caspase-3 was elevated and the apoptosis rates were significantly increased in miR-144 up-regulation group compared with negative and blank control group, while no significant difference was found between the latter 2 groups.</p><p><b>CONCLUSION</b>MiR-144 mimics may selectively up-regulate the expression of miR-144 in myocardial cells and consequently promote apoptosis and inhibit proliferation in myocardial cells.</p>

Ryanodine downregulates the expression of p-eNOS (Thr495) and improves the functions of rapamycin treated endothelial outgrowth cells / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the effects of ryanodine on rapamycin treated endothelial outgrowth cells (EOCs).</p><p><b>METHODS</b>The mononuclear cells were harvested from umbilical cord blood by Ficoll density gradient centrifugation, then induced into EOCs and expanded in vitro. The endothelial characteristics of EOCs were identified by immunostaining and fluorescent staining. The EOCs were pretreated with or without ryanodine (10 µmol/L) for 1 h, and then treated with or without rapamycin (10 nmol/L) for 24 h. Proliferation was evaluated by CCK8 and migration was measured by Transwell. The protein expression of EOCs was evaluated by immunobloting technique with total eNOS antibody and phospho-eNOS (Thr495) antibody.</p><p><b>RESULTS</b>Compared with control group, the proliferation and migration capacities of EOCs were significantly reduced while the phosphorylation of eNOS (Thr495) protein was significantly upregulated in rapamycin group (P < 0.05), expression of total eNOS was not affected by rapamycin (P > 0.05). Compared with rapamycin group, the proliferation and migration capacities of EOCs were significantly increased and the phosphorylation of eNOS (Thr495) protein was significantly downregulated in ryanodine + rapamycin group (P < 0.05). The proliferation and migration capacities, the phosphorylation of eNOS (Thr495) protein and the expression of total eNOS were not affected by ryanodine alone (P > 0.05).</p><p><b>CONCLUSIONS</b>Rapamycin reduced proliferation and migration capacities while upregulated the phosphorylation of eNOS (Thr495) protein of EOCs and these effects could be partly reversed by cotreatment with ryanodine.</p>

Effects of compound Salvia injection on number and activity of endothelial progenitor cells / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effects of Compound Salvia injection (CSI) on the number and activity of endothelial progenitor cells (EPCs).</p><p><b>METHOD</b>Mononuclear fraction of human umbilical cord blood was obtained by density gradient centrifugation and plated on fibronectin coated culture dishes. Cells were divided in to five groups: group control, group VEGF, group CSI 50, group CSI 10 and group CSI 2 (supplemented with none cytokine, VEGF 10 ng x mL(-1), CSI 50, 10, 2 microg x mL(-1), respectively). After six days in culture, cell clusters were viewed with an inverted microscope, fluorescence-activated cell sorting (FACS) analysis of PE-CD34 and FITC-VE-Cadherin was performed to detect number of EPCs, adhesion assay was performed by replating cells on fibronectin coated dishes, and then counting adherent cells.</p><p><b>RESULT</b>Numbers of EPCs of group VEGF, group CSI 10 and group CSI 2 were significantly increased as compared with those of group control ( P < 0.01, P < 0.05, P < 0.01, respectively), and numbers of EPCs of group CSI 2 were more than those of group CSI 10 and group V (P < 0.01). Compared with group control, number of EPCs of group CSI 50 was significantly decreased (P < 0.01). Compared with group control, numbers of clusters and adhesive EPCs of group CSI 10 and group CSI 2 were significantly increased, while those of group CSI 50 were significantly decreased.</p><p><b>CONCLUSION</b>Low concentration CSI can significantly promote EPCs augmentation and enhance its functional activity, while high concentration CSI significantly restrains it.</p>

Preliminary study of ALK3 downstream genes related to ventricular septum defect / 生物工程学报

To investigate the function of ALK3 gene, the gene regulation and the signaling pathway related to ventricular septum defect during heart development. The model mice with ALK3 gene knock-out via alpha-MHC-Cre/lox P system were bred. The mRNA expression level of control group was compared with that of experiment group and ALK3 downstream genes were screened using PCR-select cDNA subtraction microarray. The mRNA of control group was extracted from E11.5 normal mouse hearts, and that of experiment group, from E11.5 hearts of mice with alpha-MHC Cre(+/-) ALK3(F/+) genotype. It was found that the mice with ALK3 gene knock-out produced heart defects involving the interventricular septum. The platelet-activating factors acetylhydrolase and the transcription factor Pax-8 and so on, were down-regulated. However, the Protein Tyrosine Kinase (PTK) of Focal Adhesion Kinase (FAK) subfamily and beta subtype protein 14-3-3 were up-regulated in the alpha-MHC Cre(+/-) ALK3(F/-) mice. These data provide support that ALK3 gene played an important role during heart development. The platelet-activating factors acetylhydrolase and Pax-8 genes could be important ALK3 downstream genes in the BMP signaling pathway during interventricular septum development. PTK and beta subtype protein 14-3-3 might be regulatory factors in this pathway.

A study on myocardial Pax-8 gene / 中华儿科杂志

<p><b>OBJECTIVE</b>Conventional deletion of ALK3, also termed as bone morphogenetic protein (BMP) receptor IA, in mice might result in early embryonic lethality. To investigate the function of ALK3 in cardiac development, the cardiac-specific deletion of ALK3 in mice was made by Dr. Schneider, using Cre recombinase driven by the alpha-MHC promoter that Dr. Fukushipe worked out. Such specific deletion of ALK3 caused death in mid-gestation with defects in the trabeculae, interventricular septum, and endocardial cushion. Since ALK3 is not a cardiac-specific gene, it is extremely important to identify ALK3 downstream genes.</p><p><b>METHODS</b>Alpha-MHC Cre+/-, ALK3 F/- and alpha-MHC Cre+/-, ALK3 F/+ embryos were obtained after 20 alpha-MHC Cre+/-, ALK3 +/- mice and 20 ALK3 F/F mice were mating. The ALK3 downstream genes were screened using microarray made in Germany that could identify 25000 genes in mouse. Two populations of mRNA, one derived from the embryonic heart (11.5 days) of alpha-MHC Cre+/-, ALK3 F/- mice, and the other derived from the alpha-MHC Cre+/-, ALK3 F/+ mice, were compared. Cardiac-specific ALK3 downstream genes were identified using real time quantitative RT-PCR and in situ hybridization.</p><p><b>RESULTS</b>The expression of 12 genes, such as Pax-8 and Hox-3.5 were down-regulated in alpha-MHC Cre+/-, ALK3 F/- mouse heart. The expression of 16 genes including Ras-related protein Rab-5b and EPS-8 protein was up-regulated in the group of alpha-MHC Cre+/-, ALK3 F/-. It was found that the Box protein Pax-8 gene was down-regulated by 7.1 fold (P < 0.001) in the alpha-MHC Cre+/-, ALK3 F/- mice by real time quantitative RT-PCR. It was also revealed that the Box protein Pax-8 gene was expressed stronger in alpha-MHC Cre+/-, ALK3 F/+ than alpha-MHC Cre+/-, ALK3 F/- E11.5 days mouse heart by means of in situ hybridization.</p><p><b>CONCLUSION</b>The Box protein Pax-8 gene is an important and cardiac-specific ALK3 downstream gene in the BMP signaling pathway during inter-ventricular septum development.</p>