Deciphering Common Long QT Syndrome Using CRISPR/Cas9 in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes

From carrying potentially pathogenic genes to severe clinical phenotypes, the basic research in the inherited cardiac ion channel disease such as long QT syndrome (LQTS) has been a significant challenge in explaining gene-phenotype heterogeneity. These have opened up new pathways following the parallel development and successful application of stem cell and genome editing technologies. Stem cell-derived cardiomyocytes and subsequent genome editing have allowed researchers to introduce desired genes into cells in a dish to replicate the disease features of LQTS or replace causative genes to normalize the cellular phenotype. Importantly, this has made it possible to elucidate potential genetic modifiers contributing to clinical heterogeneity and hierarchically manage newly identified variants of uncertain significance (VUS) and more therapeutic options to be tested in vitro. In this paper, we focus on and summarize the recent advanced application of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) combined with clustered regularly interspaced short palindromic repeats/CRISPR-associated system 9 (CRISPR/Cas9) in the interpretation for the gene-phenotype relationship of the common LQTS and presence challenges, increasing our understanding of the effects of mutations and the physiopathological mechanisms in the field of cardiac arrhythmias.

Chronic Administration of COVID-19 Drugs Fluvoxamine and Lopinavir Shortens Action Potential Duration by Inhibiting the Human Ether-à-go-go-Related Gene and Cav1.2

Background: Old drugs for new indications in the novel coronavirus disease of 2019 (COVID-19) pandemic have raised concerns regarding cardiotoxicity, especially the development of drug-induced QT prolongation. The acute blocking of the cardiac hERG potassium channel is conventionally thought to be the primary mechanism of QT prolongation induced by COVID-19 drugs fluvoxamine (FLV) and lopinavir (LPV). The chronic impact of these medications on the hERG expression has yet to be determined. Methods: To investigate the effect of long-term incubation of FLV and LPV on the hERG channel, we used electrophysiological assays and molecular experiments, such as Western blot, RT-qPCR, and immunofluorescence, in HEK-293 cells stably expressing hERG and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Results: Compared to the acute effects, chronic incubation for FLV and LPV generated much lower half-maximal inhibitory concentration (IC50) values, along with a left-shifted activation curve and retarded channel activation. Inconsistent with the reduction in current, we unexpectedly found that the chronic effects of drugs promoted the maturation of hERG proteins, accompanied by the high expression of Hsp70 and low expression of Hsp90. Targeting Hsp70 using siRNA was able to reverse the effects of these drugs on hERG proteins. In addition, FLV and LPV resulted in a significant reduction of APD90 and triggered the early after-depolarizations (EADs), as well as inhibited the protein level of the L-type voltage-operated calcium channel (L-VOCC) in hiPSC-CMs. Conclusion: Chronic incubation with FLV and LPV produced more severe channel-blocking effects and contributed to altered channel gating and shortened action potential duration by inhibiting hERG and Cav1.2.

[Analysis of the effect of preventive intervention on occupational exposure of nurses after tumor particle implantation in thoracic surgery]

Objective: To study the effect of preventive intervention on occupational exposure of nurses after tumor particle implantation in thoracic surgery. Methods: In March 2020, 99 nurses who were engaged in postoperative nursing of tumor particle implantation in thoracic surgery department of our hospital from February 2019 to February 2020 were selected as the research objects. According to different preventive interventions, they were divided into observation group (51 cases) and control group (48 cases) . The observation group received preventive intervention, while the control group received routine intervention. The differences of radiation dose, psychological state and abnormal rate of important organ function between the two groups were analyzed. Results: Compared with the control group, the radiation dose of the observation group was significantly less, and the scores of anxiety and depression were lower after the intervention, the difference were statistically significant (P<0.05) . There was no significant difference of the abnormal rate of important organ function between the two groups (P>0.05) . Conclusion: Preventive intervention can reduce the risk of occupational exposure and improve the psychological status of nurses after tumor particle implantation in thoracic surgery.

LINC00641 induces the malignant progression of colorectal carcinoma through the miRNA-424-5p/PLSCR4 feedback loop

OBJECTIVE

To illustrate the role of LINC00641 in inducing the malignant progression of colorectal cancer (CRC) through the miRNA-424-5p/PLSCR4 feedback loop.

PATIENTS AND METHODS

LINC00641 levels in paired CRC and non-tumoral tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Its prognostic potential in CRC was assessed by Kaplan-Meier method. Changes in proliferative and migratory abilities of HCT116 and SW620 cells transfected with si-LINC00641 were evaluated by 5-Ethynyl-2'- deoxyuridine (EdU), cell counting kit-8 (CCK-8) and transwell assay. The feedback loop LINC00641/miRNA-424-5p/PLSCR4 was identified through Dual-Luciferase reporter assay and its involvement in CRC progression was finally explored by rescue experiments.

RESULTS

LINC00641 was upregulated in CRC tissues, which was an unfavorable factor to the overall survival of CRC. Proliferative and migratory abilities of HCT116 and SW620 cells were inhibited by knockdown of LINC00641. LINC00641 could competitively bind miRNA-424-5p, thereby abolishing its inhibitory effect on PLSCR4 expression. Knockdown of PLSCR4 could inhibit proliferative and migratory abilities of HCT116 and SW620 cells.

CONCLUSIONS

LINC00641 stimulates proliferative and migratory abilities of CRC through the miRNA-424-5p/PLSCR4 feedback loop.

[HIV infection and related factors among men who have sex with men aged 50 and above]

Objectives: To explore the HIV prevalence and related factors among MSM aged 50 and above and provide evidence on the prevention and control of HIV/AIDS. Methods: Based on an MSM social application software Blued 7.1.6, we recruited participants through online convenience sampling to collect demographic variables, behavioral and self-reported HIV infection status, etc. Univariate χ2 test and multivariate logistic regression were used to analyze the related factors of self-reported HIV infection. Results: Self-reported HIV infection rate was 17.6%(126/714) among the participants. In multivariable analysis, participants who got divorced or widowed had a 2.07(95%CI: 1.34-3.21) times greater risk of self-reported HIV-positive than those who were married. Participants unaware of HIV-related knowledge showed a 1.92(95%CI:1.21-3.04) times greater risk of self-reported HIV-positive than those with better HIV-related knowledge. Participants who have ever been diagnosed with sexually transmitted disease (STD) showed a 3.17(95%CI:2.09-4.83) times greater risk of self-reported HIV-positive than those without STD infection history. Conclusion: Our findings indicated that the self-reported HIV infection rate was high among MSM aged 50 and above. Being divorced or widowed, being unaware of HIV-related knowledge and STD infection history was proved related with self-reported HIV infection.

[Role of Orai 1-mediated store-operated calcium entry in the immune function of CD4+ T cells in septic mice]

Objective: To investigate the role of Orai1-mediated store-operated calcium entry in the immune damage of CD4⁺ T cells in septic mice. Methods: Sepsis mouse model was established by cecal ligation and puncture(CLP). Balb/c mice of clean grade were sacrificed 1, 3, and 5 days after operation. Spleen samples were harvested at given intervals. Splenic CD4⁺ T cells were selected by immunomagnetic beads and the expression of Orai1 protein was detected by western blotting, the storage operated calcium entry (SOCE) was detected by flow cytometry, the apoptosis of CD4⁺ T cells was detected by flow cytometry, the proliferation of CD4⁺ T cells was detected by CCK-8, and the IFN-γ and IL-4 were detected by enzyme-linked immunosorbent assay (ELISA). Then the expression of Orai1 protein was regulated to further detect the SOCE and immune function of splenic CD4⁺ T cells in mice. The experiment was divided into 4 groups, sham group, CLP3 group, Orai1 down group (Orai1-down group) and Orai1 up regulation group (Orai1-up group). Results: The relative expression of Orai1 protein in splenic CD4⁺ T cells in sham group was 1.03±0.16. Compared with sham group, Orai1 protein levels in CLP Group were all significantly lower (F=19.64, P=0.000 5). The increased value of splenic CD4⁺ T cells fluorescence intensity in sham group was 494±41. Compared with sham group, the levels of SOCE in CLP Group were all lower (F=30.01, P=0.001). The ratio of early and late apoptosis of CD4⁺ T cells in sham group was 8.7%±1.5%. Compared with sham group, the early and late apoptosis rates of CLP Group were significantly higher (F=32.29, P=0.000 1). The OD of sham group was 0.81±0.10 at 450 nm. Compared with sham group, the proliferation ability of splenic CD4⁺ T cells in CLP Group were significantly decreased (F=7.26, P=0.001 8). Compared with sham group, the secretion of IFN-γ and IL-4 by CD4⁺ T cells and the ratio of IFN-γ/IL-4 in CLP Group were all significantly decreased (F=19.690, 6.183, 11.230, all P<0.05). Compared with CLP3 group, the increased value of fluorescence intensity of CD4⁺ T cells was significantly decreased, the early and late apoptosis ratio of CD4⁺ T cells was significantly increased, the OD450 nm value of CD4⁺ T cells was decreased, the multiplication capacity of splenic CD4⁺ T cells were decreased, the level of IFN-γ and IL-4 secreted by T cells were decreased, and the value of IFN-γ/IL-4 in orai1-down group was decreased (t=4.819, 7.952, 2.988, 28.760, 3.140, 7.670, all P<0.05). However, Orail-up group showed the opposite trend. Conclusion: Orai1-mediated store-operated calcium entry can alleviate the immune dysfunction of CD4⁺ T cells in septic mice.

The Association of Syntax Score with Levels of Lipoprotein(a) and Inflammatory Biomarkers in Patients with Stable Coronary Artery Disease and Different Low-Density Lipoprotein Cholesterol Levels

INTRODUCTION

Lipoprotein(a) (Lp(a)) is associated with the severity of coronary lesions evaluated using Syntax score in patients with stable coronary artery disease (CAD). However, the effect of low-density lipoprotein cholesterol (LDL-C) levels on the association of Lp(a) levels with Syntax score remains unclear.

METHODS

A total of 646 patients with stable CAD were enrolled in the present study. Lp(a) levels were measured with an AU5800 Chemistry Analyzer. Syntax scores were calculated by two advanced interventional cardiologists. SPSS 22.0 was used for statistical analyses.

RESULTS

The concentration of Lp(a) ranged from 1 to 192 mg/dL. Pearson's correlation analysis showed a positive correlation between Syntax score and the level of Lp(a) (r = 0.108, p = 0.006). The LDL-C ≥100 mg/dL group presented with a higher Lp(a) level, 16 (9-29) vs 13 (7-24). Pearson's correlation analysis identified a correlation between Lp(a) level and Syntax score (r = 0.249, p < 0.001) only in the LDL-C ≥100 mg/dL group. Multivariate logistic regression analysis revealed the positive predictive value of an Lp(a) level >30 mg/dL for a Syntax score ≥23 only in the LDL-C ≥100 mg/dL group, adjusted odds ratio 2.895, p = 0.010. A receiver operating characteristic curve analysis confirmed the predictive value of Lp(a) levels for a Syntax score ≥23 in the LDL-C ≥100 mg/dL group with a cutoff value for Lp(a) >30 mg/dL.

DISCUSSION

The association between Lp(a) level and Syntax score was only maintained in the LDL-C ≥100 mg/dL group. An Lp(a) level >30 mg/dL was an independent predictor of a Syntax score ≥23 only in the LDL-C ≥100 mg/dL group. The effect of LDL-C levels on the association of Lp(a) levels with Syntax score requires further investigations.

[Baicalin regulates STIM1-mediated calcium overload and reduces apoptosis of cardiomyocytes induced by lipopolysaccharide]

Objective: To investigate the protective effect of Baicalin on apoptosis induced by lipopolysaccharide in H9C2 cardiomyocytes and its possible mechanism. Methods: In order to establish apoptosis model of H9C2 cardiomyocytes, H9C2 cardiomyocytes were cultured and divided into four groups: the control group; the baicalin group was treated with baicalin at the final concentration of 10μmol/L for 12 hours; the LPS group was stimulated with LPS at the final concentration of 1 μg/ml for 6 hours; The LPS+baicalin group was stimulated with LPS at the final concentration of 1 μg/ml for 6 hours within treated with baicalin at the final concentration of 10μmol/L for 12 hours. Collecting cell samples, CCK-8 (The Cell Counting Kit-8) was used to detect cell activity, and Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) was used to detect the expression levels of apoptosis. Laser Scanning Confocal Microscopy was used to detect the expression levels of store-operated calcium entry in H9C2 cardiomyocytes. Western blot was used to detect the protein expression levels of STIM1, cleaved-caspase3, Bax and Bcl-2. Fluorogenic quantitative PCR was used to detect the mRNA expression level of STIM1. Results: Compared with the control group, LPS-induced H9C2 cardiomyocyte survival rate decreased (P<0.05), the expression level of apoptosis increased (P<0.05), the internal flow of calcium increased (P<0.05), the expression levels of cleaved-caspase3, Bax protein levels increased (P<0.05), Bcl-2 protein level decreased (P<0.05), the expression of STIM1 mRNA and protein level increased (P<0.05). Compared with LPS group, the survival rate of H9C2 cardiomyocytes in baicalin intervention group increased (P<0.05), the expression level of apoptosis decreased (P<0.05), the internal flow of calcium decreased (P<0.05), the expression levels of cleaved-caspase3, Bax protein decreased (P<0.05), and the level of Bcl-2 protein increased (P<0.05), the expression of STIM1 mRNA and protein level decreased (P<0.05). Conclusion: Baicalin may alleviate LPS-induced cardiomyocyte apoptosis by alleviating calcium overload, and improve cell survival.

Sex-specific association of monocyte count to high-density lipoprotein ratio with SYNTAX score in patients with suspected stable coronary artery disease

Recently, the monocyte count to high-density lipoprotein cholesterol ratio (MHR) was found to be associated with the SYNTAX score in patients with both stable coronary artery disease (CAD) and acute coronary syndrome (ACS). The MHR was significantly higher in male patients. However, the sex-specific association of MHR with SYNTAX score in stable CAD was not well explored. Thus, the present study aimed to investigate the association of MHR and presence and severity of CAD evaluated by coronary angiography and the SYNTAX score in males and females.In total, 873 patients who received selective coronary angiography between March 2017 and July 2018 were included in the present study. Patients were divided into 3 groups according to MHR tertiles. The MHR was calculated by dividing the monocyte count by the high-density lipoprotein cholesterol level. CAD was defined as at least 50% diameter stenosis of a major coronary artery, including the right coronary, left main coronary, left anterior descending, and left circumflex arteries. The SYNTAX score was calculated by 2 experienced interventional cardiologists. SYNTAX score ≥23 was defined as a high SYNTAX score.Males showed a significantly higher MHR (12.2 [8.9-15.5] vs 9.3 [6.2-12.1], P < .001), accompanied by a higher prevalence of CAD (68.1% vs 53.4%, P < .001). Male sex remained an independent predictor of elevated MHR after correction for confounding factors (adjusted odds ratio [OR] 3.102, P = .001). The association between MHR and SYNTAX score was confirmed only in male stable patients with CAD (r = 0.113, P = .036). Multivariate logistic regression analysis showed that MHR was an independent predictor of SYNTAX score ≥23 only in male patients with CAD. The receiver-operating characteristic curve showed a predictive value of MHR for high SYNTAX score only in males.A higher MHR in males and a positive correlation of MHR with SYNTAX score were observed only in male stable patients with CAD. Such an easily obtained index may help interventional cardiologists detect high-risk patients before coronary catheterization, but its application may be restricted to males.

An Adiponectin Receptor Agonist Reduces Type 2 Diabetic Periodontitis

Periodontitis is twice as prevalent in diabetics as in nondiabetics, and type 2 diabetes (T2D)-associated periodontitis is severe in many cases due to the altered and aberrant functions of bone cells in hyperglycemic conditions. Therefore, developing an effective method to halt the disease process, as well as restore and regenerate lost alveolar bone to reserve the natural teeth in diabetics, is critically important. In the current study, we applied a newly discovered adiponectin receptor agonist AdipoRon (APR) in experimental periodontitis in diabetic animal models and demonstrated the underlying molecular mechanisms. We found that when APR systemically quenched the blood sugar level in diet-induced obesity (DIO) diabetic mice, it reduced osteoclast numbers and alveolar bone loss significantly due to APR's inhibition on osteoclast differentiation shown in our in vitro studies. APR also decreased the production of proinflammatory molecules CC chemokine ligand 2 and interleukin 6 in diseased gingival tissues. On the other hand, APR promoted alveolar bone regeneration through enhancing osteogenic differentiation and decreasing stromal cell-derived factor 1 in the bone marrow that facilitates stem cell migration. Same results were achieved by APR treatment of periodontitis induced in adiponectin (APN) knockout mice, indicating the ability of APR to activate the endogenous APN receptors to exert osteoanabolic effects. In summary, our study supports the notion that APR could be used as an effective multipronged approach to target T2D-associated periodontitis.

Preliminary study of the relationship between promoter methylation of the ANGPTL2 gene and coronary heart disease

BACKGROUND

Coronary heart disease (CHD) is primarily caused by atherosclerosis of coronary arteries. It is largely an inflammatory disease of the vascular wall. The inflammation is related to DNA methylation. Angiopoietin-like protein 2 (ANGPTL2) has various functions in several chronic inflammatory diseases. Macrophage-derived ANGPTL2 was reported to accelerate CHD development. It is reported that DNA hypomethylation in the promoter region of ANGPTL2 gene was associated with acute coronary syndrome (ACS), a type of CHD. Our objective was to explore the correlation between promoter methylation of the ANGPTL2 gene and CHD, and to investigate the association between methylation status and clinical characteristics of CHD patients.

METHODS

Firstly, we collected 122 CHD patients and 58 non-CHD participants from Han Chinese population and purified the peripheral blood DNA. The purified DNA was subjected to bisulfite modification. After bisulfite conversion, the target DNA locus was amplified using polymerase chain reaction (PCR), and the PCR products were measured by pyrosequencing. Finally, the methylation level was calculated according to the sequencing result, and the data were analyzed using xx software.

RESULTS

CHD patients had a relatively lower methylation levels (P50: 7.67% [P25: 6.22%, P75: 10.43%]) in the ANGPTL2 promoter region than did controls (P50: 8.25% [P25: 5.46%, P75: 17.98%], P = 0.001), indicating an association between ANGPTL2 promoter methylation and CHD (OR: 0.890; 95% CI, 0.832-0.953; adjusted P = 0.001). A breakdown analysis by gender showed that ANGPTL2 promoter methylation was associated with CHD in females (adjusted P = 0.002) but not in males (adjusted P = 0.404). We found no correlation between gene methylation and other clinical characteristics.

CONCLUSIONS

The present work provides evidence to support an association between ANGPTL2 promoter DNA methylation status and the risk profile of CHD in females. Our data indicated that in females, promoter DNA hypomethylation of the ANGPTL2 gene is associated with an increased risk of CHD.

IL6 derived from cancer-associated fibroblasts promotes chemoresistance via CXCR7 in esophageal squamous cell carcinoma

Various factors and cellular components in the tumor microenvironment are key drivers associated with drug resistance in many cancers. Here, we analyzed the factors and molecular mechanisms involved in chemoresistance in patients with esophageal squamous cell carcinoma (ESCC). We found that interleukin 6 (IL6) derived mainly from cancer-associated fibroblasts played the most important role in chemoresistance by upregulating C-X-C motif chemokine receptor 7 (CXCR7) expression through signal transducer and activator of transcription 3/nuclear factor-κB pathway. CXCR7 knockdown resulted in the inhibition of IL6-induced proliferation and chemoresistance. In addition, CXCR7 silencing significantly decreased gene expression associated with stemness, chemoresistance and epithelial-mesenchymal transition and suppressed the proliferation ability of ESCC cells in three-dimensional culture systems and angiogenesis assay. In clinical samples, ESCC patients with high expression of CXCR7 and IL6 presented a significantly worse overall survival and progression-free survival upon receiving cisplatin after operation. These results suggest that the IL6-CXCR7 axis may provide a promising target for the treatment of ESCC.

Cortical Potential Imaging of Brain Electrical Activity by Means of Parametric Projection Filter

Objectives: The objective of this study was to explore suitable spatial filters for inverse estimation of cortical potentials from the scalp electroencephalogram. The effect of incorporating noise covariance into inverse procedures was examined by computer simulations and tested in human experiment.

Methods: The parametric projection filter, which allows inverse estimation with the presence of information on the noise, was applied to an inhomogeneous three-concentric-sphere model under various noise conditions in order to estimate the cortical potentials from the scalp potentials. The method for determining the optimum regularization parameter, which can be applied for parametric inverse techniques, is also discussed.

Results: Human visual evoked potential experiment was carried out to examine the performance of the proposed restoration method. The parametric projection filter gave more localized inverse solution of cortical potential distribution than the truncated SVD and Tikhonov regularization.

Conclusion: The present simulation results suggest that incorporation of information on the noise covariance allows better estimation of cortical potentials, than inverse solutions without knowledge about the noise covariance, when the correlation between the signal and noise is low.

Mechanism of iodine release from iodoapatite in aqueous solution

Incongruent release of iodine from iodoapatite (Pb₅(VO₄)₃I) for immobilization of¹²⁹iodine, controlled by exchange of iodide and hydroxide in solution.

Are we making good use of our public resources? The false-positive rate of screening by fundus photography for diabetic macular oedema

INTRODUCTION

A large proportion of patients diagnosed with diabetic maculopathy using fundus photography and hence referred to specialist clinics following the current screening guidelines adopted in Hong Kong and United Kingdom are found to be false-positive, implying that they did not have macular oedema. This study aimed to evaluate the false-positive rate of diabetic maculopathy screening using the objective optical coherence tomography scan.

METHODS

This was a cross-sectional observational study. Consecutive diabetic patients from the Hong Kong West Cluster Diabetic Retinopathy Screening Programme with fundus photographs graded R1M1 were recruited between October 2011 and June 2013. Spectral-domain optical coherence tomography imaging was performed. Central macular thickness of ≥300 μm and/or the presence of optical coherence tomography signs of diabetic macular oedema were used to define the presence of diabetic macular oedema. Patients with conditions other than diabetes that might affect macular thickness were excluded. The mean central macular thickness in various subgroups of R1M1 patients was calculated and the proportion of subjects with central macular thickness of ≥300 μm was used to assess the false-positive rate of this screening strategy.

RESULTS

A total of 491 patients were recruited during the study period. Of the 352 who were eligible for analysis, 44.0%, 17.0%, and 38.9% were graded as M1 due to the presence of foveal 'haemorrhages', 'exudates', or 'haemorrhages and exudates', respectively. The mean (±standard deviation) central macular thickness was 265.1±55.4 μm. Only 13.4% (95% confidence interval, 9.8%-17.0%) of eyes had a central macular thickness of ≥300 μm, and 42.9% (95% confidence interval, 37.7%-48.1%) of eyes had at least one optical coherence tomography sign of diabetic macular oedema. For patients with retinal haemorrhages only, 9.0% (95% confidence interval, 4.5%-13.5%) had a central macular thickness of ≥300 μm; 23.2% (95% confidence interval, 16.6%-29.9%) had at least one optical coherence tomography sign of diabetic macular oedema. The false-positive rate of the current screening strategy for diabetic macular oedema was 86.6%.

CONCLUSION

The high false-positive rate of the current diabetic macular oedema screening adopted by the United Kingdom and Hong Kong may lead to unnecessary psychological stress for patients and place a financial burden on the health care system. A better way of screening is urgently needed. Performing additional spectral-domain optical coherence tomography scans on selected patients fulfils this need.

miRNAs Regulate hERG

BACKGROUND

The human ether-a-go-go-related gene (hERG) is the major molecular component of the rapidly activating delayed rectifier K⁺ current (I_kr ). Impairment of hERG function is believed to be a mechanism causing long-QT syndromes (LQTS). Growing evidences have shown that microRNAs (miRNAs) are involved in functional modulation of the hERG pathway. The purpose of this study was to screen and validate miRNAs that regulate the hERG pathway. The miRNAs identified in this study will provide new tools to assess the mechanism of LQTS.

METHODS

Six miRNAs were selected by algorithm predictions based on potential interaction with hERG. The effects of each miRNA on hERG were assessed by use of the Dual-Luciferase Reporter assay system, qRT-PCR, Western blotting, and confocal fluorescence microscopy. Furthermore, whole-cell patch clamp technique was used to validate the effect of miR-103a-1 on the electrophysiological characteristic of the I_kr of the hERG protein channel.

RESULTS

miR-134, miR-103a-1, miR-143, and miR-3619 significantly downregulated luciferase activity (P < 0.05) in a reporter test system. These 4 miRNAs significantly suppressed expression of hERG mRNA and protein in U2OS cells (P < 0.05).Corresponding AMOs rescued expression of hERG mRNA and protein. Confocal microscopy showed that all 4 miRNAs reduced the expression of both immature and mature hERG protein. miR-103a-1 decreased the maximum current and tail current amplitudes of hERG channel.

CONCLUSIONS

Expression and functions of hERG are regulated by specific miRNAs.