miR-20a regulates pressure overload-induced cardiac hypertrophy / 中国组织工程研究

BACKGROUND:Cardiac hypertrophy is an adaptive response of the heart to physiological and pathological stimuli such as pressure overload.It is of compensatory significance in the early stage,but if the stimulation continues,it can cause cardiomyopathy leading to heart failure.MicroRNAs are involved in the regulation of cardiac hypertrophy.However,the role of miR-20a in pressure overload-induced cardiac hypertrophy has not been reported. OBJECTIVE:To investigate the role of miR-20a in pressure overload-induced cardiac hypertrophy and the underlying mechanisms. METHODS:Transverse aortic constriction was used to induce cardiac hypertrophy in vivo and angiotensin Ⅱ was used to induce H9c2 cell models of cardiac hypertrophy in vitro.MiR-20a was overexpressed in vivo by intramyocardial injection of miR-20a overexpressing adenovirus and in vitro by transfecting miR-20a mimic into H9c2 cells.Cardiac hypertrophy was assessed by measuring heart weight/body weight ratio,cell surface area,and myocardial fibrosis.The expression levels of atrial natriuretic peptide,brain natriuretic peptide,β-myosin heavy chain and miR-20a were detected by real-time fluorescence quantitative PCR.Mitochondrial fission was detected by MitoTracker.The downstream target genes of miR-20a were predicted by RNAhybrid software. RESULTS AND CONCLUSION:(1)The expression level of miR-20a was significantly decreased in both hypertrophic cardiomyocytes and hearts(P<0.05).(2)At the animal level,overexpression of miR-20a significantly inhibited transverse aortic constriction-induced cardiac hypertrophy,including decreasing the upregulated expression level of hypertrophic marker genes(P<0.05),reduced the enlarged heart volume,reducing the increased heart weight/body weight ratio(P<0.01),reducing the increased myocardial cross-sectional area(P<0.05),and attenuating fibrosis(P<0.01).(3)At the cellular level,overexpression of miR-20a significantly inhibited angiotensin Ⅱ-induced cardiomyocyte hypertrophy,including decreasing the upregulated expression levels of atrial natriuretic peptide(P<0.05),brain natriuretic peptide(P<0.01)and β-myosin heavy chain(P<0.05),reducing the increased protein/DNA ratio(P<0.01),and suppressing the increased cell surface area(P<0.05).(4)Overexpression of miR-20a significantly inhibited angiotensin Ⅱ-induced mitochondrial fission(P<0.05).(5)The results of RNAhybrid software analysis showed that miR-20a and the mRNA 3'untranslated region of cAMP-dependent protein kinase inhibitor alpha were well complementary and the predicted binding sites were highly conserved.(6)In conclusion,miR-20a is significantly down-regulated in pressure overload-induced cardiac hypertrophy.Overexpression of miR-20a inhibits cardiac hypertrophy at both the cellular level and animal level and attenuates angiotensin Ⅱ-induced mitochondrial fission.

The repressing effect of fenoldopam on the development of thoracic aortic aneurysm in mice / 安徽医科大学学报

Objective @#To investigate whether fenoldopam (FNDP) ( an agonist of type 1 dopamine receptor) has a protective effect on thoracic aortic aneurysm ( TAA) in mice .@*Methods @#Three-week-old male C57BL/6J mice were treated with β-aminopropionitrile (BAPN) to induce TAA . The mice were divided into three groups : the con- trol group , the BAPN group , and the BAPN + FNDP group (FNDP inj ected intraperitoneally) . The incidence and survival rate of TAA were recorded . Gross anatomy of the whole aortae was ob served . Elastin staining was per- formed to assess morphological change , while immunohistochemistry was employed to evaluate the expressions of matrix metalloproteinase 2(MMP2) , matrix metalloproteinase 9( MMP9) and cluster of differentiation 68( CD68) respectively. Gelatin zymography was conducted to assess MMP2 and MMP9 activity. Reverse transcription-poly- merase chain reaction (RT-PCR) was performed to measure the mRNA expression levels of dopamine receptor D1(D1DR) , dopamine receptor d2 (D2DR) , dopamine receptor d3 (D3DR) , dopamine receptor d5 (D5DR) , in- terleukin-1β(IL-1β) , interleukin-6 (IL-6) , tumour necrosis factor-α (TNF-α) , monocyte chemoattractant pro- tein-1 (MCP-1) , alpha-smooth muscle actin ( α-SMA) and smooth muscle protein 22 -alpha (SM22α) .@*Results@#Compared to the control group , the BAPN group exhibited significant formation of TAA . Elastic fiber disruption was also ob served in the thoracic aortic wall , along with a significant decrease in the mRNA levels of D1DR and D5DR. The BAPN + FNDP group showed a significant reduction in the incidence of TAA formation and the rate of aneu- rysm rupture compared to the BAPN group . The disruption and rupture of elastic fibers in the thoracic aortic wall were significantly improved in the BAPN + FNDP group . The levels of MMP2 and MMP9 in the thoracic aortic wall significantly decreased , and the enzymatic activity of MMP2 in the serum was significantly reduced . Moreover , macrophage infiltration in the thoracic aortic wall was significantly reduced and the mRNA levels of IL-1β, IL-6 , TNF-αand MCP-1 also significantly decreased after FNDP treatment. There was no statistically significant differ- ence in the mRNA levels of α-SMA and SM22α.@*Conclusion @#FNDP shows an inhibitory effect on TAA progres- sion in mice , suggesting a potential of FNDP as a therapeutic agent for TAA .

Transcriptome analysis of Salix matsudana under cadmium stress / 生物工程学报

With the expanded application of heavy metal cadmium, soil cadmium pollution is more and more serious. In this study, using Salix matsudana as a phytoremediation candidate, we observed changes of gene expression and metabolic pathway after 1, 7 and 30 days under 2.5 mg/L and 50 mg/L cadmium stress. The result of transcriptome sequencing showed that we obtained 102 595 Unigenes; 26 623 and 32 154 differentially expressed genes (DEG) in the same concentration and different stress time; 8 550, 3 444 and 11 428 DEG with different concentrations at the same time; 25 genes closely related to cadmium stress response were screened. The changes of genes expression (such as metallothionein, ABC transporter, zinc and manganese transporter) depended on both concentration of cadmium and exposure time. The expression of several genes was obviously up-regulated after cadmium stress, for example 3,6-deoxyinosinone ketolase (ROT3) in brassinolide synthesis pathway and flavonoid synthase (FLS), flavanone-3-hydroxylase (F3H) in the synthesis pathway of brassinolide. In addition, GO analysis shows that GO entries were mainly enriched in metabolic processes including cellular processes, membranes, membrane fractions, cells, cellular fractions, catalytic activation and binding proteins in response to cadmium stress, whose number would increase along with cadmium concentration and exposure time. The reliability of transcriptome information was verified by qPCR and physiological experimental data. Response mechanisms of S. matsudana after cadmium stress were analyzed by transcriptome sequencing, which provided theoretical guidance for remediation of cadmium pollution in soil by S. matsudana.

To Explore the Double-labeling Method of Monitoring the GHRP Regulatory Function on [Ca~(2+)]i and NO on Real Time in Cardiomyocytes Under LSCM / 医学研究杂志

Objective To explore the double-labeling method of monitoring the GHRP regulatory function on [Ca2+]i and NO in cardiomyocytes of rats on real time under LSCM.Methods The reformed constant-flow Langendorff system and enzyme-dissociated was used to isolate cardiomyocytes.[Ca2+]i and NO in the cardiomyocytes of SD rats were double-labeled by their molecular probe Rhod-2/AM and DAF-FM/DA,respectively to monitor the regulatory function of GHRP on [Ca2+]i and NO on real time by LSCM.Results Ca2+ signal showed a red fluorescence and NO showed a green fluorescence while the overlapping of the two signals showed a yellow-green fluorescence by this system,and the similar effect presents in both double-labeled state and the single labeled one:GHRP induced a transient[Ca2+]i increase then followed by a plateau phase while there was not significant change in NO signal system after GHRP stimulation under the LSCM in the cardiomyocytes of rats.Conclusions After having established the double-labeling method we monitored the GHRP regulatory function on [Ca2+]i and NO on real time in cardiomyocytes of rats under LSCM causing the [Ca2+]i biphasic increase while no significant change in NO signal system.

Research on Nonlinear Characteristic of ECG Signals and Tone of Autonomic Nervous System during Water-immersion Restraint Stress in Rats / 航天医学与医学工程

Objective To definite the status of tone of autonomic nervous system during water immersion process by analyzing the nonlinear characteristic of ECG signals;To explore the relation of approximate entropy(ApEn),scaling exponent(?) changes and modulation function status of autonomic nervous system.Methods The ECG signals of rats during the process of restraint stress(RS),water-immersion restraint stress(WRS) and Vagotomy and Water-immersion restraint stress(vagotomy-WRS) were recorded.The ApEn and ? of RR intervals were calculated.Results After the stress,the differences of the value of ApEn and ? of RR intervals between RS and vagotomy-WRS groups and between different periods in vagotomy-WRS group were not significant.The value of ApEn increased in WRS group and decreased in RS group significantly.Compared with pre-stress,? showed decreased trend,all of the values smaller than 0.5 in WRS group and increased obviously,most values larger than 0.5 in RS group.Conclusion The increased ApEn and decreased ? indicates a higher intensity of parasympathetic activity.The parasympathetic activity is the predominant response of autonomic nervous system during water immersion process.