Hydroxychloroquine Attenuates hERG Channel by Promoting the Membrane Channel Degradation: Computational Simulation and Experimental Evidence for QT-Interval Prolongation with Hydroxychloroquine Treatment.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic has led to millions of confirmed cases and deaths worldwide and has no approved therapy. Currently, more than 700 drugs are tested in the COVID-19 clinical trials, and full evaluation of their cardiotoxicity risks is in high demand. METHODS: We mainly focused on hydroxychloroquine (HCQ), one of the most concerned drugs for COVID-19 therapy, and investigated the effects and underlying mechanisms of HCQ on hERG channel via molecular docking simulations. We further applied the HEK293 cell line stably expressing hERG-wild-type channel (hERG-HEK) and HEK293 cells transiently expressing hERG-p.Y652A or hERG-p.F656A mutants to validate our predictions. Western blot analysis was used to determine the hERG channel, and the whole-cell patch clamp was utilized to record hERG current (IhERG). RESULTS: HCQ reduced the mature hERG protein in a time- and concentration-dependent manner. Correspondingly, chronic and acute treatment of HCQ decreased the hERG current. Treatment with brefeldin A (BFA) and HCQ combination reduced hERG protein to a greater extent than BFA alone. Moreover, disruption of the typical hERG binding site (hERG-p.Y652A or hERG-p.F656A) rescued HCQ-mediated hERG protein and IhERG reduction. CONCLUSION: HCQ can reduce the mature hERG channel expression and IhERG via enhancing channel degradation. The QT prolongation effect of HCQ is mediated by typical hERG binding sites involving residues Tyr652 and Phe656.

Prognosis and subtype analysis of left ventricular noncompaction in adults: A retrospective multicenter study.

BACKGROUND: Left ventricular noncompaction (LVNC) is a heterogeneous myocardial disorder with an uncertain prognosis. There was a lack of studies on LVNC subtypes at present. This study sought to identify the prognosis of the overall population of LVNC and to describe the distribution of different subtypes and compare their prognosis. HYPOTHESIS: Patients with different subtypes of LVNC may have different prognoses. METHODS: Patients who fulfilled the Jenni criteria and/or Petersen criteria were included. Major adverse cardiovascular events (MACE) were defined as a combination of heart failure (HF) hospitalization and all-cause mortality. RESULTS: A total of 200 patients from four hospitals were included. The mean age at diagnosis was 48.2 years, and 61.5% of the patients were male. Left ventricular ejection fraction (LVEF) < 50% was present in 54% of the patients. Over a mean retrospective time period of 22.2 months, 47 (23.5%) patients experienced MACE. Age (hazard ratio [HR] 1.03; 95% confidence interval [CI] 1.01-1.06; p = .004), LVEF < 50% (HR 2.32; 95% CI 1.09-4.91; p = .028) and ventricular tachycardia/ventricular fibrillation (HR 2.17; 95% CI 1.08-4.37; p = .03) were significantly associated with the risk of MACE. The most common subtype was dilated LVNC (51.3%), followed by benign LVNC (21.3%) and LVNC with arrhythmias (10.5%). Patients with dilated LVNC had significantly increased cumulative incidence of MACE, HF hospitalization, and all-cause mortality (p < .05). CONCLUSIONS: Age, LVEF < 50%, and ventricular tachycardia/ventricular fibrillation were independent risk factors for prognosis of LVNC. The most common subtype was dilated LVNC, which had a worse prognosis.

Paracondylar process combined with persistent first intersegmental vertebral artery: an anatomic case report and literature review.

The paracondylar process (PCP) and the persistent first intersegmental vertebral artery (PFIA) are both rare variations at the craniovertebral junction. We report the above two variations coexisting in one cadaveric head during the training of far lateral approach in our skull base lab. The specimen simultaneously had a left occipitalized atlas associated with a PFIA and a right PCP. The previous reports, the embryogenesis, and the clinical implications of the two variations were also reviewed. Preoperative recognition of the rare variations is essential to a safe far lateral approach.

The burden of cardiovascular diseases attributable to metabolic risk factors and its change from 1990 to 2019: a systematic analysis and prediction.

Background: Metabolic disorders are the most important risk factors for cardiovascular diseases (CVDs). The purpose of this study was to systematically analyze and summarize the most recent data by age, sex, region, and time, and to forecast the future burden of diseases. Methods: Data on the burden of CVDs associated with metabolic risk factors were obtained from the Global Burden of Disease (GBD) Study 2019; and then the burden of disease was assessed using the numbers and age-standardized rates (ASR) of deaths, years of life lost (YLLs), years of life lived with disability (YLDs), and disability-adjusted life-years (DALYs) and analyzed for temporal changes, differences in age, region, sex, and socioeconomic aspects; finally, the burden of disease was predicted using an autoregressive integrated moving average (ARIMA) model. Results: From 1990 to 2019, the numbers of deaths, DALYs, YLDs, and YLLs attributed to metabolic risk factors increased by 59.3%, 51.0%, 104.6%, and 47.8%, respectively. The ASR decreased significantly. The burden of metabolic risk factor-associated CVDs was closely related to socioeconomic position and there were major geographical variations; additionally, men had a significantly greater disease burden than women, and the peak shifted later based on the age group. We predicted that the numbers of deaths and DALYs would reach 16.5 million and 324.8 million, respectively, by 2029. Conclusions: The global burden of CVDs associated with metabolic risk factors is considerable and still rising, and more effort is needed to intervene in metabolic disorders.

Left ventricular non-compaction cardiomyopathy associated with the PRKAG2 mutation.

Left ventricular non-compaction cardiomyopathy (LVNC) is one of the most common inherited cardiovascular diseases. The genetic backgrounds of most LVNC patients are not fully understood. We collected clinical data, family histories, and blood samples and performed genetic analysis using next-generation sequencing (NGS) from a Chinese family of 15 subjects. Clinically LVNC affected subjects showed marked cardiac phenotype heterogeneity. We found that these subjects with LVNC carried a missense heterozygous genetic mutation c.905G>A (p.R302Q) in γ2 subunit of AMP-activated protein kinase (PRKAG2) gene through NGS. Individuals without this mutation showed no symptoms or cardiac structural abnormalities related to LVNC. One subject was the victim of sudden cardiac death. To sum up, PRKAG2 mutation c.905G>A (p.R302Q) caused familial LVNC. Our results described a potentially pathogenic mutation associated with LVNC, which may further extend the spectrum of LVNC phenotypes related to PRKAG2 gene mutations.

Endoscopic-Assisted Trans-Lateral Ventricular Transchoroidal Fissure Trans-Aqueductal Approach for Evacuation of Severe Intraventricular Hemorrhage.

BACKGROUND: Intraventricular hemorrhage (IVH) is one of the most fatal types of intracerebral hemorrhage (ICH), especially when the third and the fourth ventricles are involved. The use of external ventricular drainage is limited for evacuation of hemorrhage in the lateral ventricles. Endoscopic surgery can provide visualized evacuation of the hemorrhage in the lateral and third ventricles. However, it is usually challenging to access the fourth ventricle using a routine endoscopic approach. METHODS: We have reported 3 cases of severe IVH with cast fourth ventricles treated using an endoscopic-assisted trans-lateral ventricular transchoroidal fissure trans-aqueductal approach. RESULTS: The average preoperative Graeb score was 11, and the average IVH volume was 75.12 mL. The IVH evacuation rate was 97.5%-100%. The average Glasgow coma scale score had increased to 12 at discharge from 6.6 at admission. At 3 months after surgery, the average modified Rankin scale score was 3. No cerebrospinal fluid shunt had been required and no surgery-related complication had occurred in any patient. CONCLUSIONS: Our results have shown that the endoscopic-assisted trans-lateral ventricular transchoroidal fissure trans-aqueductal approach is a feasible and safe endoscopic option that can achieve one-off complete removal of clots in all 4 ventricles in patients with severe IVH.

The burden of alcoholic cardiomyopathy in China and different regions around the world.

Background: Alcoholic cardiomyopathy (ACM) remains a significant public health issue with a growing global burden. The burden of ACM in China and different regions remains poorly understood. Methods: Data on ACM deaths, disability-adjusted life years (DALYs), the corresponding global age-standardized death rate (ASDR), age-standardized DALY rate and estimated annual percentage change (EAPC) were analysed based on age, sex, socio-demographic index (SDI) quintiles, different regions and in China from the Global Burden of Disease (GBD) study 2019. Results: Globally, the death rate and DALYs due to ACM were 71 723 and 2 441 108 in 2019, 33.06% and 38.79% increase from 1990, respectively. The corresponding ASDR and age-standardized DALY rate decreased with EAPC of -1.52 (95% uncertainty interval (UI) = -2.39, -0.65) and -1.12 (95% UI = -2.14, -0.10). The high-middle SDI regions, especially Eastern Europe, showed the highest number of ACM-related deaths and DALYs. The ACM-related deaths and DALYs were 2545 and 87823 in China in 2019, 171.03% and 147.17% increase from 1990, respectively. Unlike the world level, ASDR and age-standardized DALY rate also increased in China. The ACM burden is higher in men, and people with 50 to 69 years old accounted for the most. Conclusions: ACM burden in China and across the world increased substantially from 1990 to 2019. The greatest burden was borne by the high-middle SDI regions, especially by men aged 50-69 years old. Geographically and gender-age tailored strategies were needed to prevent ACM.

The LDL/HDL ratio predicts long-term risk of coronary revascularization in ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: a cohort study.

Clinical indicators do not adequately predict the long-term prognosis of patients with ST-segment elevation myocardial infarction (STEMI) following percutaneous coronary intervention (PCI). The low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio is expected to be a reliable predictor of the long-term prognosis of these patients. This study aimed to explore the correlation between the LDL/HDL ratio and long-term prognosis in STEMI patients undergoing PCI. Patients with confirmed STEMI who underwent PCI in 7 hospitals in China from January 2009 to December 2011 were enrolled. Information about clinical endpoints, including all-cause death and major adverse cardiovascular events, was collected. Overall, 915 patients were included for analysis, the average follow-up time was 112.2 months. According to the LDL/HDL ratio, the patients were divided into 3 groups using the three-quantile method: low (LDL/HDL≤1.963), medium (1.963

Cardiovascular disease burden attributable to dietary risk factors from 1990 to 2019: A systematic analysis of the Global Burden of Disease study.

BACKGROUND AND AIMS: Dietary risks have always been a major risk factor for cardiovascular diseases (CVDs), especially in young people. This article aimed to provide an updated and comprehensive view of the spatial, temporal and sexual heterogeneity in diet-attributable CVD burdens from 1990 to 2019. METHODS AND RESULTS: Data on diet-attributable CVD burdens were extracted from the Global Burden of Disease (GBD) Study 2019. Numbers and age-standardized rates (ASRs) of deaths, disability-adjusted life years (DALYs) and corresponding estimated annual percentage change (EAPC) were determined. Globally, the number of diet-attributable CVD deaths and DALYs in 2019 were 6.9 million and 153.2 million, marking 43.8% and 34.3% increases since 1990, respectively. However, ASRs of death and DALYs have declined over time. The regions with the highest ASRs of diet-related CVD deaths and DALYs were in Central Asia, whereas the lowest ASRs of CVD deaths and DALYs were observed in the high-income Asia Pacific region. Globally, men suffered higher death and DALY burdens than women. Ischemic heart disease and stroke were the leading causes of CVD deaths and DALYs, globally. Regarding the specific diet group, diets low in whole grains, high in sodium, low in fruits, low in nuts and seeds, low in vegetables and low in seafood omega-3 fatty acids contributed to CVD deaths and DALYs the most. Dietary risks accounted for a higher proportion in people aged less than 65 years old. CONCLUSIONS: Diet-attributable CVDs threaten public health, particularly in low SDI countries and younger generations. As diet-related CVDs are nation-specific, the prioritization of public health interventions should be evidence-based.

The LDL/HDL ratio predicts long-term risk of coronary revascularization in ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention: a cohort study

Clinical indicators do not adequately predict the long-term prognosis of patients with ST-segment elevation myocardial infarction (STEMI) following percutaneous coronary intervention (PCI). The low-density lipoprotein (LDL)/high-density lipoprotein (HDL) ratio is expected to be a reliable predictor of the long-term prognosis of these patients. This study aimed to explore the correlation between the LDL/HDL ratio and long-term prognosis in STEMI patients undergoing PCI. Patients with confirmed STEMI who underwent PCI in 7 hospitals in China from January 2009 to December 2011 were enrolled. Information about clinical endpoints, including all-cause death and major adverse cardiovascular events, was collected. Overall, 915 patients were included for analysis, the average follow-up time was 112.2 months. According to the LDL/HDL ratio, the patients were divided into 3 groups using the three-quantile method: low (LDL/HDL≤1.963), medium (1.963<LDL/HDL<2.595), and high (LDL/HDL≥2.595) LDL/HDL groups. The rate of coronary revascularization was higher in the high LDL/HDL group (28.52%) than in the low (17.38%, P=0.001) and medium (19.34%, P=0.010) LDL/HDL groups. The hazard ratio of coronary revascularization was significantly higher in the high LDL/HDL group than in the low (P=0.007) and medium (P=0.004) LDL/HDL groups. Increased LDL/HDL ratio was an independent risk factor for long-term coronary revascularization in STEMI patients undergoing PCI (HR=1.231, 95%CI: 1.023-1.482, P=0.028). These findings suggest that an increased LDL/HDL ratio was an independent risk factor for long-term coronary revascularization in STEMI patients undergoing PCI. The risk of coronary revascularization was significantly increased in patients with LDL/HDL≥2.595.

Cerebral cysticercosis mimicking subarachnoid hemorrhage: a case report.

BACKGROUND: Dense exudate during the calcification of cerebral cysticercosis in basal subarachnoid space was easy to be misdiagnosed as subarachnoid hemorrhage (SAH); clinical evaluation and MRI can help differentiate SAH from pseudo-SAH. CASE PRESENTATION: A case of ventricular expansion accompanied by high-density shadows in cisterna circinata cerebri was taken to the hospital for treatment due to sudden faint. This patient was diagnosed as subarachnoid hemorrhage according to computed tomography (CT) in another hospital. We believe that the high density in cisterna circinata cerebri was misdiagnosed as subarachnoid hemorrhage (SAH) 1 year ago. The main etiology of SAH is aneurysm; non-aneurysmal SAH associated with cerebral cysticercosis is extremely rare. Only 5 patients have been reported. CONCLUSION: This case indicated that although the specificity of CT for SAH is very high, the physicians should be aware of rare false positive findings, called pseudo-SAH.

Global burden of cardiovascular diseases attributable to hypertension in young adults from 1990 to 2019.

BACKGROUND: Hypertension grows into a serious public health problem among young adults, linking to a set of life-threatening cardiovascular diseases (CVDs). Young adults are not well represented in current knowledge about the CVDs burden attributable to hypertension. METHODS: In this analysis of data from the GBD (Global Burden of Disease) study 2019, we focus on young adults and provide the first comprehensive and comparative assessment of the hypertension attributable CVDs burden, in terms of its mortality and years of living with disability (YLD) from 1990 to 2019, stratified by location, sex, and development status. RESULTS: Globally in 2019, the death and YLD numbers caused by hypertension-related CVDs were 640 239 and 2 717 474 in young adults, marking a 43.0 and 86.6% increase from 1990, respectively. The corresponding mortality rate dropped by 10.5%, whereas the YLD rate increased by 16.8% during the same period. V-shaped association between CVDs burden and social development status was observed. The largest burden and the most pronounced increase were borne by middle-income countries, while high-income countries had the lowest death/YLD rate with a quicker annual decline. Men largely outpaced women in hypertension attributable CVDs mortality. Ischemic heart disease and stroke were the leading cause for death and YLD burden, correspondingly. CONCLUSIONS: Hypertension attributable CVDs burden in young adults has greatly increased from 1990 to 2019, with considerably spatiotemporal and sexual heterogeneity. The largest burden was borne by middle-income countries, especially by men. Establishment of geographically and sexually tailored strategies were needed to prevent hypertension-related CVDs in young adults.

Global Burden of Aortic Aneurysm and Attributable Risk Factors from 1990 to 2017.

Background: To date, our understanding of the global aortic aneurysm (AA) burden distribution is very limited. Objective: To assess a full view of global AA burden distribution and attributable risk factors from 1990 to 2017. Methods: We extracted data of AA deaths, disability-adjusted life years (DALYs), and their corresponding age-standardized rates (ASRs), in general and by age/sex from the 2017 Global Burden of Disease (GBD) study. The current AA burden distribution in 2017 and its changing trend from 1990 to 2017 were separately showed. The spatial divergence was discussed from four levels: global, five social-demographic index regions, 21 GBD regions, and 195 countries and territories. We also estimated the risk factors attributable to AA related deaths. Results: Globally, the AA deaths were 167,249 with an age-standardized death rate (ASDR) of 2.19/100,000 persons in 2017, among which the elderly and the males accounted for the majority. Although reductions in ASRs were observed in developed areas, AA remained an important health issue in those relatively underdeveloped areas and might be much more important in the near future. AA may increasingly affect the elderly and the female population. Similar patterns of AA DALYs burden were noted during the study period. AA burden attributable to high blood pressure and smoking decreased globally and there were many heterogeneities in their distribution. Discussion: AA maintained an incremental public health issue worldwide. The change pattern of AA burden was heterogeneous across locations, ages, and sexes and it is paramount to improve resource allocation for more effective and targeted prevention strategies. Also, prevention of tobacco consumption and blood pressure control should be emphasized.

Kv1.5 channels are regulated by PKC-mediated endocytic degradation.

The voltage-gated potassium channel Kv1.5 plays important roles in the repolarization of atrial action potentials and regulation of the vascular tone. While the modulation of Kv1.5 function has been well studied, less is known about how the protein levels of Kv1.5 on the cell membrane are regulated. Here, through electrophysiological and biochemical analyses of Kv1.5 channels heterologously expressed in HEK293 cells and neonatal rat ventricular myocytes, as well as native Kv1.5 in human induced pluripotent stem cell (iPSC)-derived atrial cardiomyocytes, we found that activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate (PMA, 10 nM) diminished Kv1.5 current (IKv1.5) and protein levels of Kv1.5 in the plasma membrane. Mechanistically, PKC activation led to monoubiquitination and degradation of the mature Kv1.5 proteins. Overexpression of Vps24, a protein that sorts transmembrane proteins into lysosomes via the multivesicular body (MVB) pathway, accelerated, whereas the lysosome inhibitor bafilomycin A1 completely prevented PKC-mediated Kv1.5 degradation. Kv1.5, but not Kv1.1, Kv1.2, Kv1.3, or Kv1.4, was uniquely sensitive to PMA treatment. Sequence alignments suggested that residues within the N terminus of Kv1.5 are essential for PKC-mediated Kv1.5 reduction. Using N-terminal truncation as well as site-directed mutagenesis, we identified that Thr15 is the target site for PKC that mediates endocytic degradation of Kv1.5 channels. These findings indicate that alteration of protein levels in the plasma membrane represents an important regulatory mechanism of Kv1.5 channel function under PKC activation conditions.

Identifying the Specific Subtype of Intracerebral Hemorrhage that is Indicated for Minimally Invasive Craniopuncture.

BACKGROUND: Surgeries for intracerebral hemorrhage (ICH) remain controversial. Our previous study found that postoperative cerebrospinal fluid (CSF) outflow was associated with high hematoma evacuation efficiency in ICH cases with intraventricular involvement (ICHV) treated with minimally invasive craniopuncture (MIC). This study was designed to identify factors that predict postoperative CSF outflow and the specific subtype of ICHV that may benefit from MIC. METHODS: A total of 189 MIC needles applied to 125 ICHV patients were retrospectively analyzed. Univariate and multivariate analyses were used to identify independent predictive factors of postoperative CSF outflow. RESULTS: A density of the whole hematoma of ≤ 59 HU [odds ratio (OR) = 8.572, 95% confidence interval (CI) 3.235-22.714, P < 0.001, standardization regression coefficients B' = 0.576] and a distance between the needle tip and the ventricular tear (tip-tear distance) of 21.79-34.15 mm (OR = 25.566, 95% CI 8.707-75.074, P < 0.001, B' = 0.883) were identified as independent predictive factors of postoperative CSF outflow. The density of the hematoma within 34.15 mm of the tear (clot 3.4) showed no statistical difference from that of the whole hematoma (P = 0.571). A density of clot 3.4 ≤ 60 HU was also a predictive factor of postoperative CSF outflow (area under curve: 0.771). CONCLUSIONS: ICHV patients who meet the following conditions may benefit from MIC: (1) The MIC needle tip can be placed in the hematoma 21.79-34.15 mm from the ventricular tear; (2) the density of the whole hematoma is low (≤ 59 HU); and (3) the density of clot 3.4 is also low (≤ 60 HU). Future perspective studies should be conducted on this specific patient subtype.

Endoscopic-Assisted Translateral Ventricular Transchoroidal Fissure Approach for Evacuation of Medial-Type Thalamic Hemorrhage: Case Series.

BACKGROUND: Although surgeries for intracerebral hemorrhage remain controversial, endoscopic surgery is considered a promising surgical treatment. The most fatal type of thalamic hemorrhage is the medial type, which is always combined with expansion of the hematoma into the third ventricle. The current endoscopic approach to this lesion involves injury to the mediodorsal nucleus of the thalamus (MDT). CASE DESCRIPTION: We report 5 cases of medial thalamic hemorrhage with third intraventricular involvement treated by an endoscopic-assisted translateral ventricular transchoroidal fissure approach. The preoperative average volume of the parenchymal hematomas was 9.63 mL, while the preoperative average volume of the intraventricular hematomas was 23.35 mL. The average surgical duration was 80.6 minutes. No intraoperative MDT incision was needed in any patient. The evacuation rates of parenchymal and intraventricular hematomas were 74.21%-98.84% and 85.89%-99.51%, respectively. Three months after the surgery, the average Glasgow Coma Scale scores improved to 13.8 from 7.2 preoperatively. No ventriculoperitoneal shunt was needed in any patient. CONCLUSIONS: The endoscopic-assisted translateral ventricular transchoroidal fissure approach is a safe and effective approach for evacuation of a medial thalamic hemorrhage with third intraventricular involvement. This approach allows parenchymal hematoma evacuation through the rupture of the third ventricle without incising the MDT in the lateral ventricle.

Exendin-4 reverses high glucose-induced endothelial progenitor cell dysfunction via SDF-1ß/CXCR7-AMPK/p38-MAPK/IL-6 axis.

AIM: Exendin-4, a glucagon-like peptide-1 (GLP-1) analog, has been used for treating diabetes mellitus (DM). However, its effects on improving the dysfunction of high glucose (HG)-induced endothelial progenitor cells (EPCs) remain unclear. The present study explored the effects of Exendin-4 on improving dysfunction of EPCs and the underlying mechanism. METHODS: EPCs were isolated from SD rats and identified by flow cytometry. Next, the EPCs were treated by HG and high or low concentration of Exendin-4, and cell viability, migration and tube formation were, respectively, examined by performing MTT assay, wound-healing assay and tube formation assay. Interleukin-6 (IL-6) secretion was measured by enzyme-linked immunosorbent assay (ELISA). The protein expressions of relative stromal-derived growth factor-1ß (SDF-1ß), C-X-C chemokine receptor type 7 (CXCR7), AMP-activated protein kinase (AMPK), p38 and expressions of CXCR7 and IL-6 in EPCs were measured by Western blot. The cell behaviors of EPCs treated by HG and Exendin-4 with or without silencing of CXCR7 and IL-6 were detected. RESULTS: Exendin-4 reversed the inhibitory effects of HG on viability, migration and tube formation of EPCs and on SDF-1ß/CXCR7-AMPK pathway in EPCs in a dose-dependent manner. Moreover, Exendin-4 promoted the effects of HG on IL-6 level in EPCs through the promotion of p38-MAPK phosphorylation and reduction of cleaved caspase-3 protein expressions in EPCs. However, silencing of CXCR7 and IL-6 reversed the effects of Exendin-4 on cell behaviors, inactivated SDF-1ß/CXCR7-AMPK pathway and increased cleaved caspase-3 expression in EPCs. CONCLUSIONS: Exendin-4 could ameliorate HG-induced EPC dysfunction through regulating the production of IL-6 via SDF-1ß/CXCR7-AMPK/p38-MAPK axis.

Circular RNA circPITX1 knockdown inhibits glycolysis to enhance radiosensitivity of glioma cells by miR-329-3p/NEK2 axis.

BACKGROUND: Numerous circular RNAs (circRNAs) have been recognized as vital modulators of human malignancies, including glioma. Whereas, the functional role of circRNA Pituitary Homeo Box 1 (circPITX1) in the radioresistance of glioma cells remains largely uncertain. METHODS: Quantitative real-time PCR (qRT-PCR) or western blot analysis was employed to examine the expression of circPITX1, microRNA (miR)-329-3p and NIMA-related kinase 2 (NEK2). 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to determine cell viability. Glycolysis was assessed by commercial kits and western blot analysis. Colony formation assay was conducted to analyze cell survival and clonogenicity capacity. The relationship among circPITX1, miR-329-3p and NEK2 was confirmed via dual-luciferase reporter assay. The in vivo function of circPITX1 was evaluated by tumor xenograft assay. RESULTS: Expression of circPITX1 and NEK2 was up-regulated in glioma tissues and cells, while miR-329-3p exhibited reverse trend. CircPITX1 knockdown repressed viability, glycolysis and colony formation, but promoted radiosensitivity of glioma cells, as well as inhibited tumor growth in vivo. MiR-329-3p was a target miRNA of circPITX1 and miR-329-3p deficiency reversed knockdown of circPITX1-mediated glycolysis inhibition and radioresistance reduction. MiR-329-3p exerted inhibitory effects on glycolysis and radioresistance of glioma cells by targeting NEK2. CircPITX1 facilitated NEK2 expression by sponging miR-329-3p. Glycolytic inhibitor 2-deoxy-d-glucose (2-DG) disposition weakened the promoted impact on glycolysis caused by circPITX1. CONCLUSION: CircPITX1 knockdown reduced glycolysis to contribute to radiosensitivity in glioma through miR-329-3p/NEK2 axis, providing a possible mechanism of circPITX1 in the development of glioma.

Mechanical stretch increases Kv1.5 current through an interaction between the S1-S2 linker and N-terminus of the channel.

The voltage-gated potassium channel Kv1.5 plays important roles in atrial repolarization and regulation of vascular tone. In the present study, we investigated the effects of mechanical stretch on Kv1.5 channels. We induced mechanical stretch by centrifuging or culturing Kv1.5-expressing HEK 293 cells and neonatal rat ventricular myocytes in low osmolarity (LO) medium and then recorded Kv1.5 current (IKv1.5) in a normal, isotonic solution. We observed that mechanical stretch increased IKv1.5, and this increase required the intact, long, proline-rich extracellular S1-S2 linker of the Kv1.5 channel. The low osmolarity-induced IKv1.5 increase also required an intact intracellular N terminus, which contains the binding motif for endogenous Src tyrosine kinase that constitutively inhibits IKv1.5 Disrupting the Src-binding motif of Kv1.5 through N-terminal truncation or mutagenesis abolished the mechanical stretch-mediated increase in IKv1.5 Our results further showed that the extracellular S1-S2 linker of Kv1.5 communicates with the intracellular N terminus. Although the S1-S2 linker of WT Kv1.5 could be cleaved by extracellularly applied proteinase K (PK), an N-terminal truncation up to amino acid residue 209 altered the conformation of the S1-S2 linker and made it no longer susceptible to proteinase K-mediated cleavage. In summary, the findings of our study indicate that the S1-S2 linker of Kv1.5 represents a mechanosensor that regulates the activity of this channel. By targeting the S1-S2 linker, mechanical stretch may induce a change in the N-terminal conformation of Kv1.5 that relieves Src-mediated tonic channel inhibition and results in an increase in IKv1.5.

Exendin-4 regulates endoplasmic reticulum stress to protect endothelial progenitor cells from high-glucose damage.

BACKGROUND: High glucose affects the function of endothelial cells by increasing oxidative stress. Studies have found that exendin-4 can improve wound healing in diabetic mice and mice with normal blood glucose. However, the mechanism of exendin-4 in endothelial progenitor cells under high-glucose condition has not been fully elucidated. METHODS: Diabetic mouse models were established to investigate the effects of exendin-4 on endothelial progenitor cells in diabetic mice. Serum superoxide dismutase (SOD) and malondialdehyde (MDA) were determined by WST-8 and thiobarbituric acid (TBA) colorimetry, respectively. Cell viability, apoptosis and reactive oxygen species (ROS) were detected by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry. Gene and protein expressions were determined by Quantitative reverse transcription PCR (qRT-PCR) assay and Western blot (WB). RESULTS: The results showed that in diabetic mice, exendin-4 did not affect blood glucose or body weight, moreover, it improved aortic diastolic function, increased SOD activity and down-regulated malondialdehyde (MDA) level in the mice. In addition, exendin-4 also increased endothelial progenitor cell (EPCs) viability and reduced cell apoptosis through inhibiting p38 MAPK pathway and reducing endoplasmic reticulum stress and ROS. CONCLUSION: Exndin-4 can alleviate diabetes-caused damage to mice, moreover, it reduced endoplasmic reticulum stress and ROS through inhibiting p38 MAPK pathway in MPCs cells under high-glucose condition, thus increasing cell viability and reducing cell apoptosis.