Key roles of autophagosome/endosome maturation mediated by Syntaxin17 in methamphetamine-induced neuronal damage in mice.

BACKGROUND: Autophagic defects are involved in Methamphetamine (Meth)-induced neurotoxicity. Syntaxin 17 (Stx17), a member of the SNARE protein family, participating in several stages of autophagy, including autophagosome-late endosome/lysosome fusion. However, the role of Stx17 and potential mechanisms in autophagic defects induced by Meth remain poorly understood. METHODS: To address the mechanism of Meth-induced cognitive impairment, the adenovirus (AV) and adeno-associated virus (AAV) were injected into the hippocampus for stereotaxis to overexpress Stx17 in vivo to examine the cognitive ability via morris water maze and novel object recognition. In molecular level, the synaptic injury and autophagic defects were evaluated. To address the Meth induced neuronal damage, the epidermal growth factor receptor (EGFR) degradation assay was performed to evaluate the degradability of the "cargos" mediated by Meth, and mechanistically, the maturation of the vesicles, including autophagosomes and endosomes, were validated by the Co-IP and the GTP-agarose affinity isolation assays. RESULTS: Overexpression of Stx17 in the hippocampus markedly rescued the Meth-induced cognitive impairment and synaptic loss. For endosomes, Meth exposure upregulated Rab5 expression and its guanine-nucleotide exchange factor (GEF) (immature endosome), with a commensurate decreased active form of Rab7 (Rab7-GTP) and impeded the binding of Rab7 to CCZ1 (mature endosome); for autophagosomes, Meth treatment elicited a dramatic reduction in the overlap between Stx17 and autophagosomes but increased the colocalization of ATG5 and autophagosomes (immature autophagosomes). After Stx17 overexpression, the Rab7-GTP levels in purified late endosomes were substantially increased in parallel with the elevated mature autophagosomes, facilitating cargo (Aß42, p-tau, and EGFR) degradation in the vesicles, which finally ameliorated Meth-induced synaptic loss and memory deficits in mice. CONCLUSION: Stx17 decrease mediated by Meth contributes to vesicle fusion defects which may ascribe to the immature autophagosomes and endosomes, leading to autophagic dysfunction and finalizes neuronal damage and cognitive impairments. Therefore, targeting Stx17 may be a novel therapeutic strategy for Meth-induced neuronal injury.

Effects of exposure to 3,6-DBCZ on neurotoxicity and AhR pathway during early life stages of zebrafish (Danio rerio).

Polyhalogenated carbazoles (PHCZs) are emerging environmental pollutants, yet limited information is available on their embryotoxicity and neurotoxicity. Therefore, the current work was performed to investigate the adverse effects of 3,6-dibromocarbazole (3,6-DBCZ), a typical PHCZs homolog, on the early life stages of zebrafish larvae. It revealed that the 96-hour post-fertilization (hpf) median lethal concentration (LC50) value of 3,6-DBCZ in zebrafish larvae was determined to be 0.7988 mg/L. Besides, 3,6-DBCZ reduced survival rates at concentrations ≥ 1 mg/L and decreased hatching rates at ≥ 0.25 mg/L at 48 hpf. In behavior tests, it inhibited locomotor activities and reduced the frequency of recorded acceleration states in response to optesthesia (a sudden bright light stimulus) at concentrations ≥ 160 µg/L. Meanwhile, 3,6-DBCZ exposure decreased the frequency of recorded acceleration states in the startle response (tapping mode) at concentrations ≥ 6.4 µg/L. Pathologically, with the transgenic zebrafish model (hb9-eGFP), we observed a strikingly decreased axon length and number in motor neurons after 3,6-DBCZ treatment, which may be ascribed to the activation of the AhR signaling pathway, as evidenced by the molecular docking analysis and Microscale thermophoresis (MST) assay suggested that 3,6-DBCZ binding to AhR-ARNT2 compound proteins. Through interaction with AhR-ARNT, a striking reduction of the anti-oxidative stress (sod1/2, nqo1, nrf2) and neurodevelopment-related genes (elavl3, gfap, mbp, syn2a) were observed after 3,6-DBCZ challenge, accompanied by a marked increased inflammatory genes (TNFß, IL1ß, IL6). Collectively, our findings reveal a previously unrecognized adverse effect of 3,6-DBCZ on zebrafish neurodevelopment and locomotor behaviors, potentially mediated through the activation of the AhR pathway. Furthermore, it provides direct evidence for the toxic concentrations of 3,6-DBCZ and the potential target signaling in zebrafish larvae, which may be beneficial for the risk assessment of the aquatic ecosystems.

Failure of intravenous nifekalant cardioversion as an independent predictor for persistent atrial fibrillation recurrence after catheter ablation.

AIMS: Nifekalant is a class III antiarrhythmic drug that exerts antiarrhythmic effects by inhibiting rapid rectifying potassium channels and extending the effective refractory period of cardiomyocytes. It has a high success rate in converting atrial fibrillation (AF) to sinus rhythm. Whether the failure of intravenous nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation has not been reported. METHODS: A total of 92 patients with drug-refractory persistent AF were retrospectively enrolled. After all ablations, intravenous nifekalant was administrated. Patients were assigned to the success group (group 1) and failure group (group 2) based on nifekalant cardioversion results and followed for 12 months to note any episode of atrial arrhythmia recurrence. RESULTS: Each group included 46 patients. After 12 months of follow-up, nine (19.6%) patients from group 1 and 23 (50.0%) patients from group 2 had a recurrence of atrial tachyarrhythmia (P = 0.002). AF duration and type 2 diabetes were strongly associated with failure of intravenous nifekalant cardioversion. Univariable Cox proportional hazard regression showed that failure of intravenous nifekalant cardioversion, AF duration, and type 2 diabetes were potential risk factors. Multivariable Cox proportional hazard regression showed that failure of nifekalant cardioversion was statistically associated with AF recurrence (adjusted RR = 2.257, 95% CI: 1.006-5.066, P = 0.048). Failure of intravenous nifekalant cardioversion could bring a positive effect on the prognostic differentiation when added into the multivariable model (0.767 ± 0.042 vs. 0.774 ± 0.045, P = 0.025). CONCLUSION: Failure of nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation.

Mystery of bisphenol F-induced nonalcoholic fatty liver disease-like changes: Roles of Drp1-mediated abnormal mitochondrial fission in lipid droplet deposition.

As one of the major substitutes for bisphenol A (BPA), bisphenol F (BPF) has been widely used. Our previous study demonstrated that BPF exposure facilitates lipid droplet deposition in hepatic cells, contributing to nonalcoholic fatty liver disease (NAFLD)-like changes. However, the underlying mechanisms remain poorly understood. Here, with a metabolic cage system, we observed the perturbation of energy metabolism in mice treated with BPF. BPF obviously suppressed metabolic capacity, which manifested as decreased energy expenditure, low O2 consumption and CO2 levels in mice. Consistent with the in vivo results, a Seahorse XF Cell Mito Stress Test showed significant reductions in mitochondrial ATP production capacity, maximum respiratory capacity, and residual respiratory capacity after BPF treatment in an in vitro study. Electron microscopy revealed a striking increase in mitochondrial fission that was synchronous with excessive expression and activation of dynamin-related protein 1 (Drp1). Intriguingly, chemical inhibition of Drp1 by Mdivi-1 and/or silencing of Drp1 dramatically hampered mitochondrial fission and ameliorated BPF-induced lipid droplet deposition both in mouse liver and human hepatic cells. Mechanistically, mitochondrial dynamics imbalance played prominent roles in these processes, since suppression of Drp1 by chemical inhibition or knockdown substantially reversed BPF-induced mitochondrial fission and ameliorated the suppression of mitochondrial metabolism as well as excessive mitochondrial ROS, which was verified to be key to lipid droplet deposition. Collectively, the findings of the current study reveal previously unrecognized effects involving Drp1-mediated mitochondrial injury in BPF-induced lipid droplet deposition. Therefore, targeted intervention against mitochondrial dysfunction may be a promising therapeutic strategy for BPF-induced NAFLD-like changes.

Left atrial appendage occlusion combined with cryoballoon or radiofrequency ablation: One-year follow-up comparison.

Background: A one-stop procedure involving catheter ablation and left atrial appendage occlusion (LAAO) is an option for high-risk atrial fibrillation patients. Few studies have reported the efficacy and safety of cryoballoon ablation (CBA) combined with LAAO, and no studies have compared the combination of LAAO with CBA or radiofrequency ablation (RFA). Methods: A total of 112 patients were enrolled in the present study; 45 patients received CBA combined with LAAO (group 1), and 67 patients received RFA combined with LAAO (group 2). Patient follow-up was performed for 1 year to detect peri-device leaks (PDLs) and safety outcomes (defined as a composite of peri-procedural and follow-up adverse events). Results: The number of PDLs at the median 59 days follow-up was comparable between the two groups (33.3% in group 1 vs. 37.3% in group 2, p = 0.693). Safety outcomes were also comparable between the two groups (6.7% in group 1 vs. 7.5% in group 2, p = 1.000). Multivariable regression showed that PDLs risk and safety outcomes were all similar between the two groups. Subgroup analysis of PDLs indicated no significant differences. Follow-up safety outcomes were related to anticoagulant medication, and patients without PDLs were more likely to discontinue antithrombotic therapy. The total procedure and ablation times were all significantly shorter for group 1. Conclusion: When compared with left atrial appendage occlusion combined with radiofrequency, left atrial appendage occlusion combined with cryoballoon ablation has the same risk of peri-device leaks and safety outcomes, but the procedure time was significantly reduced.

Clinical Influence of Ethanol Infusion in the Vein of Marshall on Left Atrial Appendage Occlusion: Results of Feasibility and Safety during Implantation and at 60-Day Follow-Up.

BACKGROUND: Ethanol infusion in the vein of Marshall (EI-VOM) has the advantages of reducing the burden of atrial fibrillation (AF), decreasing AF recurrence, and facilitating left pulmonary vein isolation and mitral isthmus bidirectional conduction block. Moreover, it can lead to prominent edema of the coumadin ridge and atrial infarction. Whether these lesions will affect the efficacy and safety of left atrial appendage occlusion (LAAO) has not yet been reported. OBJECTIVES: To explore the clinical outcome of EI-VOM on LAAO during implantation and after 60 days of follow-up. METHODS: A total of 100 consecutive patients who underwent radiofrequency catheter ablation combined with LAAO were enrolled in this study. Patients who also underwent EI-VOM at the same period of LAAO were assigned to group 1 (n = 26), and those who did not undergo EI-VOM were assigned to group 2 (n = 74). The feasibility outcomes included intra-procedural LAAO parameters and follow-up LAAO results involving device-related thrombus, a peri-device leak (PDL), and adequate occlusion (defined as a PDL ≤ 5 mm). Safety outcomes were defined as the composites of severe adverse events and cardiac function. Outpatient follow-up was performed 60 days post-procedure. RESULTS: Intra-procedural LAAO parameters, including the rate of device reselection, rate of device redeployment, rate of intra-procedural PDLs, and total LAAO time, were comparable between groups. Furthermore, intra-procedural adequate occlusion was achieved in all patients. After a median of 68 days, 94 (94.0%) patients received their first radiographic examination. Device-related thrombus was not detected in the follow-up populations. The incidence of follow-up PDLs was similar between the two groups (28.0% vs. 33.3%, p = 0.803). The incidence of adequate occlusion was comparable between groups (96.0% vs. 98.6%, p = 0.463). In group 1, none of the patients experienced severe adverse events. Ethanol infusion significantly reduced the right atrial diameter. CONCLUSIONS: The present study showed that undergoing an EI-VOM procedure did not impact the operation or effectiveness of LAAO. Combining EI-VOM with LAAO was safe and effective.

Explainable machine learning model reveals its decision-making process in identifying patients with paroxysmal atrial fibrillation at high risk for recurrence after catheter ablation.

BACKGROUND: A number of models have been reported for predicting atrial fibrillation (AF) recurrence after catheter ablation. Although many machine learning (ML) models were developed among them, black-box effect existed widely. It was always difficult to explain how variables affect model output. We sought to implement an explainable ML model and then reveal its decision-making process in identifying patients with paroxysmal AF at high risk for recurrence after catheter ablation. METHODS: Between January 2018 and December 2020, 471 consecutive patients with paroxysmal AF who had their first catheter ablation procedure were retrospectively enrolled. Patients were randomly assigned into training cohort (70%) and testing cohort (30%). The explainable ML model based on Random Forest (RF) algorithm was developed and modified on training cohort, and tested on testing cohort. In order to gain insight into the association between observed values and model output, Shapley additive explanations (SHAP) analysis was used to visualize the ML model. RESULTS: In this cohort, 135 patients experienced tachycardias recurrences. With hyperparameters adjusted, the ML model predicted AF recurrence with an area under the curve of 66.7% in the testing cohort. Summary plots listed the top 15 features in descending order and preliminary showed the association between features and outcome prediction. Early recurrence of AF showed the most positive impact on model output. Dependence plots combined with force plots showed the impact of single feature on model output, and helped determine high risk cut-off points. The thresholds of CHA2DS2-VASc score, systolic blood pressure, AF duration, HAS-BLED score, left atrial diameter and age were 2, 130 mmHg, 48 months, 2, 40 mm and 70 years, respectively. Decision plot recognized significant outliers. CONCLUSION: An explainable ML model effectively revealed its decision-making process in identifying patients with paroxysmal atrial fibrillation at high risk for recurrence after catheter ablation by listing important features, showing the impact of every feature on model output, determining appropriate thresholds and identifying significant outliers. Physicians can combine model output, visualization of model and clinical experience to make better decision.

Role of the Peli1-RIPK1 Signaling Axis in Methamphetamine-Induced Neuroinflammation.

Severe neurological inflammation is one of the main symptoms of methamphetamine (meth)-induced brain injury. Studies have demonstrated that meth exposure facilitates neuroinflammation via Pellino E3 ubiquitin protein ligase 1 (Peli1)-mediated signaling. However, the involved mechanisms remain incompletely understood. Herein, we used Peli1-/- mice and Peli1-knockdown microglial BV2 cells to decipher the roles of Peli1 and downstream signaling in meth-induced neuroinflammation. After meth administration for seven consecutive days, Peli1-/- mice exhibited better learning and memory behavior and dramatically lower interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, and IL-6 levels than wild-type mice. Moreover, in vitro experiments revealed that Peli1 knockdown significantly attenuated the meth-induced upregulation of cytokines. Besides, meth markedly activated and increased the levels of receptor-interacting protein kinase 1 (RIPK1), and Peli1 knockout or knockdown prevented these effects, indicating that RIPK1 participated in meth-induced Peli1-mediated inflammation. Specifically, treating the cells with necrostatin-1(Nec-1), an antagonist of RIPK1, remarkably inhibited the meth-induced increase in IL-1ß, TNF-α, and IL-6 expression, confirming the involvement of RIPK1 in Peli1-mediated neuroinflammation. Finally, meth induced a dramatic transfer of the mixed lineage kinase domain-like protein, a downstream effector of RIRK1, to the cell membrane, disrupting membrane integrity and causing cytokine excretion. Therefore, targeting the Peli1-RIPK1 signaling axis is a potentially valid therapeutic approach against meth-induced neuroinflammation.

Methamphetamine-mediated dissemination of ß-amyloid: Disturbances in endocytosis, transport and clearance of ß-amyloid in microglial BV2 cells.

Methamphetamine (Meth) abuse can cause neurodegenerative-like changes, such as those observed in Alzheimer's disease (AD), characterized by extracellular amyloid-ß (Aß) deposition. The "spreading hypothesis" suggests that pathological Aß spreads over the entire brain, which depends on Aß endocytosis, transport and clearance. However, whether Meth exposure impacts these effects remains poorly understood. Microglia play an important role in the clearance of Aß. Therefore, the effects of microglia on Aß ingestion, degradation, and efflux under Meth challenge were investigated. Meth significantly engulfed and elicited a massive accumulation of Aß42 when extracellular administration of FAM-Aß42, accompanied by an increase in endocytosis-associated mRNA and protein expression, including TREM2 and VSP35. Meanwhile, FAM-Aß42 degradation was obviously retarded, since the colocalization of Aß42 and LDL, Aß42 and lysosomes was decreased, and syntaxin 17 might be involved in this process. Intriguingly, Meth dramatically facilitated FAM-Aß42 dissemination in microglia, characterized by the massive overlap between FAM-Aß42 and transferrin, which is destined to be excreted out of the cells. The facilitation of FAM-Aß42 spreading was further validated by the increased colocalization of FAM-Aß42 and CD63. Mechanistically, Meth mediated Aß42 spreading through the exosomal pathway, since an exosomal inhibitor remarkably hindered this process. Therefore, the current study elucidated a novel mechanism of Meth-induced accelerated progression in neurodegenerative disease, and targeting the inhibition of Aß1-42 efflux in microglia might provide beneficial effects for Meth-induced neural damage.

Targeting Aß and p-Tau Clearance in Methamphetamine-Induced Alzheimer's Disease-Like Pathology: Roles of Syntaxin 17 in Autophagic Degradation in Primary Hippocampal Neurons.

Methamphetamine (Meth), a central nervous system (CNS) stimulant with strong neurotoxicity, causes progressive cognitive impairment with characterized neurodegenerative changes. However, the mechanism underlying Meth-induced pathological changes remains poorly understood. In the current study, Meth elicited a striking accumulation of the pathological proteins hyperphosphorylated tau (p-tau) and amyloid beta (Aß) in primary hippocampal neurons, while the activation of autophagy dramatically ameliorated the high levels of these pathological proteins. Interestingly, after the Meth treatment, Aß was massively deposited in autophagosomes, which were remarkably trapped in early endosomes. Mechanistically, syntaxin 17 (Stx17), a key soluble n-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptor (SNARE) protein responsible for autophagosome and mature endosome/lysosome fusion, was significantly downregulated and hindered in combination with autophagosomes. Notably, adenovirus overexpression of Stx17 in primary neurons facilitated autophagosome-mature endosome/lysosome fusion, which dramatically reversed the Meth-induced increases in the levels of p-tau, Aß, beta-secretase (Bace-1), and C-terminal fragments (CTFs). Immunofluorescence assays showed that Stx17 retarded the Meth-induced Aß, p-tau, and Bace-1 accumulation in autophagosomes and facilitated the translocation of these pathological proteins to lysosomes, which indicated the importance of Stx17 via enhanced autophagosome-mature endosome/lysosome fusion. Therefore, the current study reveals a novel mechanism involving Meth-induced high levels of pathological proteins in neurons. Targeting Stx17 may provide a novel therapeutic strategy for Meth-induced neurodegenerative changes.

MicroRNA-4487 regulates vascular smooth muscle cell proliferation, migration and apoptosis by targeting RAS p21 protein activator 1.

BACKGROUND: Dysregulation of microRNA (miRNA) is involved in the pathogenesis of a variety of diseases, including atherosclerosis (AS). However, the role of miRNA-4487 (miR-4487) in the development of AS is not fully clarified. This study is intended to investigate the regulatory effects of miR-4487 on the proliferation, migration and apoptosis of vascular smooth muscle cells (VSMCs) and the related mechanisms. METHODS: Oxidized low-density lipoprotein (ox-LDL) was employed to induce the dysfunction of VSMCs. Subsequently, miR-4487 expression was detected by quantitative real-time PCR. Afterward, the expression levels of RAS p21 protein activator 1 (RASA1) and apoptosis-related proteins (Bcl-2, Bax, Cleaved caspase 3, Cleaved caspase 9) were detected by Western blotting. The proliferation, migration and apoptosis of VSMCs were then detected by CCK-8, BrdU, Transwell and flow cytometry assays, respectively. Moreover, a dual-luciferase reporter gene assay was executed to verify the targeting between miR-4487 to the RASA1 3'-untranslated region (3'-UTR). RESULTS: ox-LDL treatment increased miR-4487 expression and decreased RASA1 expression in VSMCs. Additionally, ox-LDL treatment promoted the proliferation and migration of VSMCs, but inhibited apoptosis. Besides, the effects of ox-LDL treatment on the proliferation, migration and apoptosis of VSMCs were attenuated by the transfection of miR-4487 inhibitors. Furthermore, miR-4487 directly targeted the 3'-UTR of RASA1 mRNA and repressed the expression level of RASA1. Also, RASA1 knockdown reversed the effects of miR-4487 inhibition on VSMCs. CONCLUSION: MiR-4487 promotes VSMCs viability and migration and inhibits apoptosis by targeting RASA1 in VSMCs, by which it promotes the pathogenesis of AS.

Mystery of methamphetamine-induced autophagosome accumulation in hippocampal neurons: loss of syntaxin 17 in defects of dynein-dynactin driving and autophagosome-late endosome/lysosome fusion.

Methamphetamine (METH), a psychoactive-stimulant facilitates massive accumulation of autophagosomes and causes autophagy-associated neuronal death. However, the underlying mechanisms involving METH-induced auto-phagosome accumulation remain poorly understood. In the current study, autophagic flux was tracked by mRFP-GFP-LC3 adenovirus, 900 µM METH treatment was found to significantly disrupt autophagic flux, which was further validated by remarkable increase of co-localized of LC3 and SQSTM1/p62, enhancement of LC3-II and SQSTM1/p62 protein levels, and massive autophagosome puncta aggregation. With the cycloheximide (CHX) treatment, METH treatment was displayed a significant inhibition of SQSTM1/p62 degradation. Therefore, the mRNAs associated with vesicle degradation were screened, and syntaxin 17 (Stx17) and dynein-dynactin mRNA levels significantly decreased, an effect was proved in protein level as well. Intriguingly, METH induced autophagosome accumulation and autophagic flux disturbance was incredibly retarded by overexpression of Stx17, which was validated by the restoration of the fusion autophagosome-late endosome/lysosome fusion. Moreover, Stx17 overexpression obviously impeded the METH-induced decrease of co-localization of the retrograded motor protein dynein/dynactin and autophagosome-late endosome, though the dynein/dynactin proteins were not involved in autophagosome-late endosome/lysosome fusion. Collectively, our findings unravel the mechanism of METH-induced autophagosome accumulation involving autophagosome-late endosome/lysosome fusion deficiency and that autophagy-enhancing mechanisms such as the overexpression of Stx17 may be therapeutic strategies for the treatment of METH-induced neuronal damage.

Prevalence of subcutaneous implantable cardioverter-defibrillator based on template ECG screening and ineligible surface ECG predicting factors in patients with hypertrophic cardiomyopathy in China.

The subcutaneous implantable cardioverter-defibrillator (S-ICD) may provide comparable protection while avoiding the disadvantage of transvenous lead, but the abnormal features of the hypertrophic cardiomyopathy (HCM) electrocardiogram (ECG) make it a challenge for S-ICD template screening. We aimed to investigate S-ICD eligibility according to the S-ICD manufacturer's surface ECG screening template in China, and further analyze its corresponding ineligible predicting factors in 12-lead suface ECG. A total of 179 HCM patients (114 males; mean age: 45 ± 14 years) underwent S-ICD screening at rest and on exercise, among which 91 patients (50.8%) were eligible for S-ICD. Among the patients who passed screening, 43 (47.3%) had 3 vectors eligibility; 64 (70.3%) screening qualified on both sides; 10 patients (11.0%) passed the screening while the electrodes located only on the left parasternal line versus 17 patients (18.7%) moved to the right line. The secondary sensing vector (Lead III) was mostly appropriate (53.6%), followed by the primary sensing vector (lead II, 53.1%) and the alternate sensing vector (Lead I, 46.9%). Higher R wave was the major cause, accounted for 70.5%, for screening failure. There existed significant difference in T wave in lead II, aVF, V5 and V6, adds R/T ratio in lead V5 and V6, between the screening success group (group A) and screening failure group (group B) at rest and on exercise. A multivariable logistic regression analysis was performed to identify that R/T ≤ 3.5 in lead V5 was the independent factor to predict the screening ineligibility, with odds ratio 3.648. S-ICD screening success is 50.8% in HCM patients, which is much lower than that in other studies. R/T ≤ 3.5 in lead V5 in 12-lead surface ECG was an independent predicting factor for screening failure.

Circular RNA expression profiles of persistent atrial fibrillation in patients with rheumatic heart disease.

OBJECTIVE: To investigate the expression profile of circular RNAs (circRNAs) and proposed circRNA-microRNA (miRNA) regulatory network in atrial fibrillation (AF). METHODS: Atrial tissues from patients with persistent AF with rheumatic heart disease and non-AF myocardium with normal hearts were collected for circRNA differential expression analyses by high-throughput sequencing. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to predict the potential functions of the differentially expressed genes and AF-related pathways. Co-expression networks of circRNA-miRNA were constructed based on the correlation analyses between the differentially expressed RNAs. Quantitative reverse transcription polymerase chain reaction (PCR) was performed to validate the results. RESULTS: A total of 108 circRNAs were found to be differentially expressed in AF. Among them, 51 were up-regulated, and 57 were down-regulated. Dysregulated circRNAs were validated by quantitative real-time PCR. The GO and KEGG pathway enrichment analyses were executed to determine the principal functions of the significantly deregulated genes. Furthermore, we constructed correlated expression networks between circRNAs and miRNAs. circRNA19591, circRNA19596, and circRNA16175 interacted with 36, 28, and 18 miRNAs, respectively; miR-29b-1-5p and miR-29b-2-5p were related to 12 down-regulated circRNAs, respectively. CONCLUSION: Our findings provide a novel perspective on circRNAs involved in AF due to rheumatic heart disease and establish the foundation for future research of the potential roles of circRNAs in AF.

Intramyocardial delivery of bFGF with a biodegradable and thermosensitive hydrogel improves angiogenesis and cardio-protection in infarcted myocardium.

Basic fibroblast growth factor (bFGF), a known angiogenic factor, may provide a potential strategy for the treatment of myocardial infarction (MI), but it is limited by a relatively short half-life. Dex-PCL-HEMA/PNIPAAm hydrogel provides a reservoir for the controlled release of growth factors. The aim of the current study was to evaluate the effects of bFGF incorporated into a Dex-PCL-HEMA/PNIPAAm hydrogel on angiogenesis and cardiac health in a rat model of acute MI, induced by coronary artery ligation. Phosphate-buffered solution (PBS group), Dex-PCL-HEMA/PNIPAAm hydrogel (Gel group), bFGF in phosphate-buffered solution (bFGF group) or bFGF in hydrogel (Gel + bFGF group) was injected into a peri-infarcted area of cardiac tissue immediately following MI. On day 30 post-surgery, cardiac function was assessed by echocardiography, apoptosis index by terminal deoxynucleotidyl transferase dUTP nick-end labeling assessment and vascular development by immunohistochemical staining. The findings demonstrated that injection of bFGF along with hydrogel induced angiogenesis, reduced collagen content, MI area and cell apoptosis and improved cardiac function compared with the injection of either bFGF or hydrogel alone. bFGF incorporated with Dex-PCL-HEMA/PNIPAAm hydrogel injection induces angiogenesis, attenuates cardiac remodeling and improves cardiac function following MI.

Intramyocardial delivery of VEGF165 via a novel biodegradable hydrogel induces angiogenesis and improves cardiac function after rat myocardial infarction.

Vascular endothelial growth factor (VEGF), an independent mitogen, has been reported to induce angiogenesis and thus attenuates the damage induced by myocardial infarction (MI). VEGF165 is the most abundant and predominant isoform of VEGF. This study investigates whether this effect could be strengthened by local intramyocardial injection of VEGF165 along with a novel biodegradable Dex-PCL-HEMA/PNIPAAm hydrogel and ascertains its possible mechanism of action. Rat models of myocardial infarction were induced by coronary artery ligation. Phosphate-buffered saline (PBS group), Dex-PCL-HEMA/PNIPAAm hydrogel (Gel group), phosphate-buffered saline containing VEGF165 (VP group), and hydrogel containing VEGF165 (VPG group) were injected into a peri-infarcted area of cardiac tissue immediately after myocardial infarction, respectively. The sham group was thoracic but without myocardial infarction. The injection of VEGF165 along with a hydrogel induced angiogenesis, reduced collagen content and MI area, inhibited cell apoptosis, increased the level of VEGF165 protein and the expression of flk-1 and flt-1, and improved cardiac function compared with the injection of either alone after MI in rats. The results suggest that injection of VEGF165 along with a hydrogel acquires more cardioprotective effects than either alone in rat with MI by sustained release of VEGF165, then may enhance the feedback between VEGF and its receptors flk-1 and flt-1.