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Abstract Increasing scRNA-seq data in cardiovascular research have substantially improved our knowledge on the development of the cardiovascular system and the mechanisms underlying cardiovascular diseases. However, the single-cell transcriptome datasets were dispersed in literature and no resource for cardiovascular systems and diseases. Here, we constructed an organized resource CardioAtlas, which provides comprehensive analysis results for > 1,929,000 cells in 27 human data sets and > 1,088,000 cells in 39 mouse data sets. Through large-scale literature retrieval and manual annotation, we constructed 12 and 15 scRNA-seq reference atlas for common human and mouse cardiovascular systems and diseases, covering 43 and 39 cell types. In particular, CardioAtlas provides five analytic modules, including cell-type prediction, identification of marker genes, functional enrichment analysis, identification of cell-type-specific transcription regulons, and cell-cell communication analysis. In addition, users can upload scRNA-seq data for personalized analysis. CardioAtlas is available at http://bio-bigdata.hrbmu.edu.cn/CardioAtlas . CardioAtlas provides the first comprehensive and well-crafted reference atlas of cardiovascular systems and diseases and describes in detail previously unrecognized cell populations across a large number of humans and mice.

Abstract Arteriovenous fistulas (AVFs) are the most common vascular access points for hemodialysis (HD), but they have a high incidence of postoperative dysfunction, mainly due to excessive neointimal hyperplasia (NIH). Our previous studies have revealed a highly conserved LncRNA-LncDACH1 as an important regulator of cardiomyocyte and fibroblast proliferation. Herein, we find that LncDACH1 regulates NIH in AVF in male mice with conditional knockout of smooth muscle cell-specific LncDACH1 and in male mice model of AVF with LncDACH1 overexpression by adeno-associated virus. Mechanistically, silence of LncDACH1 activates p-AKT through promoting the expression of heat shock protein 90 (HSP90) and serine/arginine-rich splicing factor protein kinase 1 (SRPK1). Moreover, LncDACH1 is transcriptionally activated by transcription factor KLF9 that binds directly to the promoter region of the LncDACH1 gene. In this work, during AVF NIH, LncDACH1 is downregulated by KLF9 and promotes NIH through the HSP90/ SRPK1/ AKT signaling axis.

Abstract Translational control is crucial for protein production in various biological contexts. Here, we use Ribo-seq and RNA-seq to show that genes related to oxidative phosphorylation are translationally downregulated during heart regeneration. We find that Nat10 regulates the expression of Uqcr11 and Uqcrb mRNAs in mouse and human cardiomyocytes. In mice, overexpression of Nat10 in cardiomyocytes promotes cardiac regeneration and improves cardiac function after injury. Conversely, treating neonatal mice with Remodelin—a Nat10 pharmacological inhibitor—or genetically removing Nat10 from their cardiomyocytes both inhibit heart regeneration. Mechanistically, Nat10 suppresses the expression of Uqcr11 and Uqcrb independently of its ac4C enzyme activity. This suppression weakens mitochondrial respiration and enhances the glycolytic capacity of the cardiomyocytes, leading to metabolic reprogramming. We also observe that the expression of Nat10 is downregulated in the cardiomyocytes of P7 male pig hearts compared to P1 controls. The levels of Nat10 are also lower in female human failing hearts than non-failing hearts. We further identify the specific binding regions of Nat10, and validate the pro-proliferative effects of Nat10 in cardiomyocytes derived from human embryonic stem cells. Our findings indicate that Nat10 is an epigenetic regulator during heart regeneration and could potentially become a clinical target.

Abstract Cardiomyocyte maturation is the final stage of heart development, and abnormal cardiomyocyte maturation will lead to serious heart diseases. CXXC zinc finger protein 1 (Cfp1), a key epigenetic factor in multi‐lineage cell development, remains underexplored in its influence on cardiomyocyte maturation. This study investigates the role and mechanisms of Cfp1 in this context. Cardiomyocyte‐specific Cfp1 knockout (Cfp1‐cKO) mice died within 4 weeks of birth. Cardiomyocytes derived from Cfp1‐cKO mice showed an inhibited maturation phenotype, characterized by structural, metabolic, contractile, and cell cycle abnormalities. In contrast, cardiomyocyte‐specific Cfp1 transgenic (Cfp1‐TG) mice and human induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) overexpressing Cfp1 displayed a more mature phenotype. Mechanistically, deficiency of Cfp1 led to a reduction in trimethylation on lysine 4 of histone H3 (H3K4me3) modification, accompanied by the formation of ectopic H3K4me3. Furthermore, Cfp1 deletion decreased the level of H3K4me3 modification in adult genes and increased the level of H3K4me3 modification in fetal genes. Collectively, Cfp1 modulates the expression of genes crucial to cardiomyocyte maturation by regulating histone H3K4me3 modification, thereby intricately influencing the maturation process. This study implicates Cfp1 as an important molecule regulating cardiomyocyte maturation, with its dysfunction strongly linked to cardiac disease.

Summary: Long non-coding RNAs (lncRNAs) play widespread roles in various processes. However, there is still limited understanding of the precise mechanisms through which they regulate early stage cardiomyocyte differentiation. In this study, we identified a specific lncRNA called LHX1-DT, which is transcribed from a bidirectional promoter of LIM Homeobox 1 (LHX1) gene. Our findings demonstrated that LHX1-DT is nuclear-localized and transiently elevated expression along with LHX1 during early differentiation of cardiomyocytes. The phenotype was rescued by overexpression of LHX1 into the LHX1-DT−/− hESCs, indicating LHX1 is the downstream of LHX1-DT. Mechanistically, we discovered that LHX1-DT physically interacted with RNA/histone-binding protein PHF6 during mesoderm commitment and efficiently replaced conventional histone H2A with a histone variant H2A.Z at the promoter region of LHX1. In summary, our work uncovers a novel lncRNA, LHX1-DT, which plays a vital role in mediating the exchange of histone variants H2A.Z and H2A at the promoter region of LHX1.

Myocardial infarction (MI), the most serious of the ischemic heart diseases, is accompanied by myocardial metabolic disorders and the loss of cardiomyocytes. Increasing evidence has shown that long noncoding RNAs (lncRNAs) are involved in various pathological conditions such as cancer and cardiovascular diseases (CVDs), and are emerging as a novel biomarker for these disorders. This study aims to investigate the regulatory role and mechanisms of lncRNAs in myocardial remodeling in the setting of MI. We find that post-infarcted hearts exhibit a reduction of adenosine triphosphate (ATP) and an alteration of the glucose and lipid metabolism genes cluster of differentiation 36 (CD36), hexokinase 1 (HK1), and clucose transporter 4 (GLUT4), accompanied by cardiomyocyte pyroptosis. We then identify a previously unknown conserved lncRNA, AK009126 (cardiomyocyte pyroptosis-associated lncRNA, CPAL), which is remarkably upregulated in the myocardial border zone of MI mice. Importantly, the adeno-associated virus 9 (AAV9)-mediated silencing of endogenous CPAL by its short hairpin RNA (shRNA) partially abrogates myocardial metabolic alterations and cardiomyocyte pyroptosis during MI in mice. Mechanistically, CPAL is shown to bind directly to nuclear factor kappa B (NFκB) and to act as an activator of NFκB to induce NFκB phosphorylation in cardiomyocytes. We also find that CPAL upregulates caspase-1 expression at the transcriptional level and consequently promotes the release of interleukin (IL)-18 and IL-1β from cardiomyocytes. Collectively, our findings reveal the conserved lncRNA CPAL as a new regulator of cardiac metabolic abnormalities and cardiomyocyte pyroptosis in the setting of MI and suggest CPAL as a new therapeutic target to protect cardiomyocytes against ischemic injury in infarcted hearts.

Introduction: The principal voltage-gated Na+ channel, NaV1.5 governs heart excitability and conduction. NaV1.5 dysregulation is responsible for ventricular arrhythmias and subsequent sudden cardiac death (SCD) in post-infarct hearts. The transcription factor Meis1 performs a significant role in determining differentiation fate and regenerative capability of cardiomyocytes. However, the functions of Meis1 in ischemic arrhythmias following myocardial infarction (MI) are still largely undefined. Objectives: Here we aimed to study whether Meis1 could act as a key regulator to mediate cardiac Na+ channel and its underlying mechanisms. Methods: Heart-specific Meis1 overexpression was established by AAV9 virus injection in C57BL/6 mice. The QRS duration, the incidence of ventricular arrhythmias and cardiac conduction velocity were evaluated by ECG, programmed electrical stimulation and optical mapping techniques respectively. The conventional patch clamp technique was performed to explore the INa characteristics of isolated mouse ventricular myocytes. In vitro, Meis1 was also overexpressed in hypoxic-treated neonatal cardiomyocytes. The analysis of immunoblotting and immunofluorescence were used to detect the changes in the expression of NaV1.5 in each group. Results: We found that forced expression of Meis1 rescued the prolongation of QRS complex, produced anti-arrhythmic activity and improved epicardial conduction velocity in infarcted mouse hearts. In terms of mechanisms, cardiac electrophysiological changes of MI mice can be ameliorated by the recovery of Meis1, which is characterized by the restoration of INa current density and NaV1.5 expression level of cardiomyocytes in the marginal zone of MI mouse hearts. Furthermore, in vitro studies showed that Meis1 was also able to rescue hypoxia-induced decreased expression and dysfunction of NaV1.5 in ventricular myocytes. We further revealed that E3 ubiquitin ligase CDC20 led to the ubiquitination and degradation of Meis1, which blocked the transcriptional regulation of SCN5A by Meis1 and ultimately led to the electrophysiological remodeling in ischemic-hypoxic cardiomyocytes. Conclusion: CDC20 mediates ubiquitination of Meis1 to govern the transcription of SCN5A and cardiac electrical conduction in mouse cardiomyocytes. This finding uncovers a new mechanism of NaV1.5 dysregulation in infarcted heart, and provides new therapeutic strategies for malignant arrhythmias and sudden cardiac death following MI.

Introduction: While acute Coronavirus disease 2019 (COVID-19) affects the cardiovascular (CV) system according to recent data, an increased CV risk has been reported also during long-term follow-up (FU). In addition to other CV pathologies in COVID-19 survivors, an enhanced risk for arrhythmic events and sudden cardiac death (SCD) has been observed. While recommendations on post-discharge thromboprophylaxis are conflicting in this population, prophylactic short-term rivaroxaban therapy after hospital discharge showed promising results. However, the impact of this regimen on the incidence of cardiac arrhythmias has not been evaluated to date.Methods: To investigate the efficacy of this therapy, we conducted a single center, retrospective analysis of 1804 consecutive, hospitalized COVID-19 survivors between April and December 2020. Patients received either a 30-day post-discharge thromboprophylaxis treatment regimen using rivaroxaban 10 mg every day (QD) (Rivaroxaban group (Riva); n = 996) or no thromboprophylaxis (Control group (Ctrl); n = 808). Hospitalization for new atrial fibrillation (AF), new higher-degree Atrioventricular-block (AVB) as well as incidence of SCD were investigated in 12-month FU [FU: 347 (310/449) days].Results: No differences in baseline characteristics (Ctrl vs Riva: age: 59.0 (48.9/66.8) vs 57 (46.5/64.9) years, p = n.s.; male: 41.5% vs 43.7%, p = n.s.) and in the history of relevant CV-disease were observed between the two groups. While hospitalizations for AVB were not reported in either group, relevant rates of hospitalizations for new AF (0.99%, n = 8/808) as well as a high rate of SCD events (2.35%, n = 19/808) were seen in the Ctrl. These cardiac events were attenuated by early post-discharge prophylactic rivaroxaban therapy (AF: n = 2/996, 0.20%, p = 0.026 and SCD: n = 3/996, 0.30%, p < 0.001) which was also observed after applying a logistic regression model for propensity score matching (AF: χ2-statistics = 6.45, p = 0.013 and SCD: χ2-statistics = 9.33, p = 0.002). Of note, no major bleeding complications were observed in either group.Conclusion: Atrial arrhythmic and SCD events are present during the first 12 months after hospitalization for COVID-19. Extended prophylactic Rivaroxaban therapy after hospital discharge could reduce new onset of AF and SCD in hospitalized COVID-19 survivors.

N6-methyladenosine (m6A), as the most abundant modification of mammalian messenger RNAs, is essential for tissue development and pathogenesis. However, the biological significance of m6A methylation in cardiac differentiation and development remains largely unknown. Here, we identify that the downregulation of m6A demethylase ALKBH5 is responsible for the increase of m6A methylation and cardiomyocyte fate determination of human embryonic stem cells (hESCs) from mesoderm cells (MESs). In contrast, ALKBH5 overexpression remarkably blocks cardiomyocyte differentiation of hESCs. Mechanistically, KDM5B and RBBP5, the components of H3K4 modifying enzyme complexes, are identified as downstream targets for ALKBH5 in cardiac-committed hESCs. Loss of function of ALKBH5 alters the expression of KDM5B and RBBP5 through impairing stability of their mRNAs, which in turn promotes the transcription of GATA4 by enhancing histone H3 Lys4 trimethylation (H3K4me3) at the promoter region of GATA4. Taken together, we reveal a previously unidentified role of m6A demethylase ALKBH5 in determining cardiac lineage commitment of hESCs.

Abstract Cardiovascular diseases such as myocardial infarction (MI) is a major contributor to human mortality and morbidity. The mammalian adult heart almost loses its plasticity to appreciably regenerate new cardiomyocytes after injuries, such as MI and heart failure. The neonatal heart exhibits robust proliferative capacity when exposed to varying forms of myocardial damage. The ability of the neonatal heart to repair the injury and prevent pathological left ventricular remodeling leads to preserved or improved cardiac function. Therefore, promoting cardiomyocyte proliferation after injuries to reinitiate the process of cardiomyocyte regeneration, and suppress heart failure and other serious cardiovascular problems have become the primary goal of many researchers. Here, we review recent studies in this field and summarize the factors that act upon the proliferation of cardiomyocytes and cardiac repair after injury and discuss the new possibilities for potential clinical treatment strategies for cardiovascular diseases.

IntroductionCardiovascular events are common in COVID-19. While the use of anticoagulation during hospitalization has been established in current guidelines, recommendations regarding antithrombotic therapy in the post-discharge period are conflicting.MethodsTo investigate this issue, we conducted a retrospective follow-up (393 ± 87 days) of 1,746 consecutive patients, hospitalized with and surviving COVID-19 pneumonia at a single tertiary medical center between April and December 2020. Survivors received either 30-day post-discharge antithrombotic treatment regime using prophylactic direct oral anticoagulation (DOAC; n = 1,002) or dipyridamole (n = 304), or, no post-discharge antithrombotic treatment (Ctrl; n = 440). All-cause mortality, as well as cardiovascular mortality (CVM) and further cardiovascular outcomes (CVO) resulting in hospitalization due to pulmonary embolism (PE), myocardial infarction (MI) and stroke were investigated during the follow-up period.ResultsWhile no major bleeding events occured during follow-up in the treatment groups, Ctrl showed a high but evenly distributed rate all-cause mortality. All-cause mortality (CVM) was attenuated by prophylactic DOAC (0.6%, P < 0.001) and dipyridamole (0.7%, P < 0.001). This effect was also evident for both therapies after propensity score analyses using weighted binary logistic regression [DOAC: B = −3.33 (0.60), P < 0.001 and dipyridamole: B = −3.04 (0.76), P < 0.001]. While both treatment groups displayed a reduced rate of CVM [DOAC: B = −2.69 (0.74), P < 0.001 and dipyridamole: B = −17.95 (0.37), P < 0.001], the effect in the DOAC group was driven by reduction of both PE [B−3.12 (1.42), P = 0.012] and stroke [B = −3.08 (1.23), P = 0.028]. Dipyridamole significantly reduced rates of PE alone [B = −17.05 (1.01), P < 0.001].ConclusionLate cardiovascular events and all-cause mortality were high in the year following hospitalization for COVID-19. Application of prophylactic DOAC or dipyridamole in the early post-discharge period improved mid- and long-term CVO and all-cause mortality in COVID-19 survivors.

Abstract With the high morbidity and mortality rates, cardiovascular diseases have become one of the most concerning diseases worldwide. The heart of adult mammals can hardly regenerate naturally after injury because adult cardiomyocytes have already exited the cell cycle, which subseqently triggers cardiac remodeling and heart failure. Although a series of pharmacological treatments and surgical methods have been utilized to improve heart functions, they cannot replenish the massive loss of beating cardiomyocytes after injury. Here, we summarize the latest research progress in cardiac regeneration and heart repair through altering cardiomyocyte fate plasticity, which is emerging as an effective strategy to compensate for the loss of functional cardiomyocytes and improve the impaired heart functions. First, residual cardiomyocytes in damaged hearts re-enter the cell cycle to acquire the proliferative capacity by the modifications of cell cycle-related genes or regulation of growth-related signals. Additionally, non-cardiomyocytes such as cardiac fibroblasts, were shown to be reprogrammed into cardiomyocytes and thus favor the repair of damaged hearts. Moreover, pluripotent stem cells have been shown to transform into cardiomyocytes to promote heart healing after myocardial infarction (MI). Furthermore, in vitro and in vivo studies demonstrated that environmental oxygen, energy metabolism, extracellular factors, nerves, non-coding RNAs, etc. play the key regulatory functions in cardiac regeneration. These findings provide the theoretical basis of targeting cellular fate plasticity to induce cardiomyocyte proliferation or formation, and also provide the clues for stimulating heart repair after injury.

Cardiac ischemia–reperfusion (I/R) injury represents a key threat to human health. This study reveals that the long noncoding RNA lncRNA-CIRBIL is protective against I/R injury by inhibiting the nuclear translocation of Bclaf1.

AimsWhile COVID-19 affects the cardiovascular system, the potential clinical impact of cardiovascular biomarkers on predicting outcomes in COVID-19 patients is still unknown. Therefore, to investigate this issue we analyzed the prognostic potential of cardiac biomarkers on in-hospital and long-term post-discharge mortality of patients with COVID-19 pneumonia.MethodsSerum soluble ST2, VCAM-1, and hs-TnI were evaluated upon admission in 280 consecutive patients hospitalized with COVID-19-associated pneumonia in a single, tertiary care center. Patient clinical and laboratory characteristics and the concentration of biomarkers were correlated with in-hospital [Hospital stay: 11 days (10; 14)] and post-discharge all-cause mortality at 1 year follow-up [FU: 354 days (342; 361)].Results11 patients died while hospitalized for COVID-19 (3.9%), and 11 patients died during the 1-year post-discharge follow-up period (n = 11, 4.1%). Using multivariate analysis, VCAM-1 was shown to predict mortality during the hospital period (HR 1.081, CI 95% 1.035;1.129, p = 0.017), but not ST2 or hs-TnI. In contrast, during one-year FU post hospital discharge, ST2 (HR 1.006, 95% CI 1.002;1.009, p < 0.001) and hs-TnI (HR 1.362, 95% CI 1.050;1.766, p = 0.024) predicted mortality, although not VCAM-1.ConclusionIn patients hospitalized with Covid-19 pneumonia, elevated levels of VCAM-1 at admission were associated with in-hospital mortality, while ST2 and hs-TnI might predict post-discharge mortality in long term follow-up.

The coronavirus disease 2019 (COVID-19), a pneumonia caused by a novel coronavirus, was reported in December 2019. COVID-19 is highly contagious and has rapidly developed from a regional epidemic into a global pandemic. As yet, no effective drugs have been found to treat this virus. This study, an ongoing multicenter and blind randomized controlled trial (RCT), is being conducted at ten study sites in Heilongjiang Province, China, to investigate the efficacy and safety of Triazavirin (TZV) versus its placebo in COVID-19 patients. A total of 240 participants with COVID-19 are scheduled to be enrolled in this trial. Participants with positive tests of throat swab virus nucleic acid are randomized (1:1) into two groups: standard therapy plus TZV or standard therapy plus placebo for a 7-day treatment with a 21-day follow-up. The primary outcome is the time to clinical improvement of the subjects. Secondary outcomes include clinical improvement rate, time to alleviation of fever, mean time and proportion of obvious inflammatory absorption in the lung, conversion rate of repeated negative virus nucleic acid tests, mortality rate, and conversion rate to severe and critically severe patients. Adverse events, serious adverse events, liver function, kidney function, and concurrent treatments will be monitored and recorded throughout the trial. The results of this trial should provide evidence-based recommendations to clinicians for the treatment of COVID-19.

No therapeutics have been proven effective yet for the treatment of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To assess the efficacy and safety of Triazavirin therapy for COVID-19, we conducted a randomized, double-blinded controlled trial involving hospitalized adult patients with COVID-19. Participants were enrolled from ten sites, and were randomized into two arms of the study with a ratio of 1:1. Patients were treated with Triazavirin 250 mg versus a placebo three or four times a day for 7 d. The primary outcome was set as the time to clinical improvement, defined as normalization of body temperature, respiratory rate, oxygen saturation, cough, and absorption of pulmonary infection by chest computed tomography (CT) until 28 d after randomization. Secondary outcomes included individual components of the primary outcome, the mean time and proportion of inflammatory absorption in the lung, and the conversion rate to a repeated negative SARS-CoV-2 nucleic acid test of throat swab sampling. Concomitant therapeutic treatments, adverse events, and serious adverse events were recorded. Our study was halted after the recruitment of 52 patients, since the number of new infections in the participating hospitals decreased greatly. We randomized 52 patients for treatment with Triazavirin (n = 26) or a placebo (n = 26). We found no differences in the time to clinical improvement (median, 7 d versus 12 d; risk ratio (RR), 2.0; 95% confidence interval (CI), 0.7–5.6; p = 0.2), with clinical improvement occurring in ten patients in the Triazavirin group and six patients in the placebo group (38.5% versus 23.1%; RR, 2.1; 95% CI, 0.6–7.0; p = 0.2). All components of the primary outcome normalized within 28 d, with the exception of absorption of pulmonary infection (Triazavirin 50.0%, placebo 26.1%). Patients in the Triazavirin group used less frequent concomitant therapies for respiratory, cardiac, renal, hepatic, or coagulation supports. Although no statistically significant evidence was found to indicate that Triazavirin benefits COVID-19 patients, our observations indicated possible benefits from its use to treat COVID-19 due to its antiviral effects. Further study is required for confirmation.

Heart failure (HF) is the common consequences of various cardiovascular diseases, often leading to severe cardiac output deficits with a high morbidity and mortality. In recent years, light emitting diodes-based therapy (LEDT) has been widely used in multiple cardiac diseases, while its modulatory effects on cardiac function with HF still remain unclear. Therefore, the objective of this study was to investigate the effects of LED-Red irradiation on cardiac function in mice with HF and to reveal its mechanisms. In this study, we constructed a mouse model of HF. We found that LED-Red (630 nm) was an effective wavelength for the treatment of HF. Meanwhile, the application of LED-Red therapy to treat HF mice improved cardiac function, ameliorate heart morphology, reduced pulmonary edema, as well as inhibited collagen deposition. Moreover, LED-Red therapy attenuated the extent of perivascular fibrosis. Besides, LED-Red irradiation promoted calcium transients in cardiomyocytes as well as upregulated ATP synthesis, which may have positive implications for contractile function in mice with HF. Collectively, we identified that LED-Red exerts beneficial effects on cardiac function in HF mice possibly by promoting the synthesis of ATP.

Bone marrow-derived mesenchymal stem cells (BMSCs) have been suggested to possess the capacity to differentiate into different cell lineages. Maintaining a balanced stem cell differentiation program is crucial to the bone microenvironment and bone development. MicroRNAs (miRNAs) have played a critical role in regulating the differentiation of BMSCs into particular lineage. However, the role of miR-149-3p in the adipogenic and osteogenic differentiation of BMSCs has not been extensively discovered. In this study, we aimed to detect the expression levels of miR-149-3p during the differentiation of BMSCs and investigate whether miR-149-3p participated in the lineage choice of BMSCs or not. Compared with mimic-negative control (NC), miR-149-3p mimic decreased the adipogenic differentiation potential of BMSCs and increased the osteogenic differentiation potential. Further analysis revealed that overexpression of miR-149-3p repressed the expression of fat mass and obesity-associated (FTO) gene through binding to the 3ʹ UTR of the FTO mRNA. Also, the role of miR-149-3p mimic in inhibiting adipogenic lineage differentiation and potentiating osteogenic lineage differentiation was mainly through targeting FTO, which also played an important role in regulating body weight and fat mass. In addition, BMSCs treated with miR-149-3p anti-miRNA oligonucleotide (AMO) exhibited higher potential to differentiate into adipocytes and lower tendency to differentiate into osteoblasts compared with BMSCs transfected with NC. In summary, our results detected the effects of miR-149-3p in cell fate specification of BMSCs and revealed that miR-149-3p inhibited the adipogenic differentiation of BMSCs via a miR-149-3p/FTO regulatory axis. This study provided cellular and molecular insights into the observation that miR-149-3p was a prospective candidate gene for BMSC-based bone tissue engineering in treating osteoporosis. Keywords: miRNA, osteoporosis, osteogenesis, adipogenesis, BMSC, differentiation, FTO

BackgroundJ-waves represent a common finding in routine ECGs (5-6%) and are closely linked to ventricular tachycardias. While arrhythmias and non-specific ECG alterations are a frequent finding in COVID-19, an analysis of J-wave incidence in acute COVID-19 is lacking.MethodsA total of 386 patients consecutively, hospitalized due to acute COVID-19 pneumonia were included in this retrospective analysis. Admission ECGs were analyzed, screened for J-waves and correlated to clinical characteristics and 28-day mortality.ResultsJ-waves were present in 12.2% of patients. Factors associated with the presence of J-waves were old age, female sex, a history of stroke and/or heart failure, high CRP levels as well as a high BMI. Mortality rates were significantly higher in patients with J-waves in the admission ECG compared to the non-J-wave cohort (J-wave: 14.9% vs. non-J-wave 3.8%, p = 0.001). After adjusting for confounders using a multivariable cox regression model, the incidence of J-waves was an independent predictor of mortality at 28-days (OR 2.76 95% CI: 1.15-6.63; p = 0.023). J-waves disappeared or declined in 36.4% of COVID-19 survivors with available ECGs for 6-8 months follow-up.ConclusionJ-waves are frequently and often transiently found in the admission ECG of patients hospitalized with acute COVID-19. Furthermore, they seem to be an independent predictor of 28-day mortality.

Background/Aims: Melatonin possesses many biological activities such as antioxidant and anti-aging. Cardiac progenitor cells (CPCs) have emerged as a promising therapeutic strategy for myocardial infarction (MI). However, the low survival of transplanted CPCs in infarcted myocardium limits the successful use in treating MI. In the present study, we aimed to investigate if melatonin protects against oxidative stress-induced CPCs damage and enhances its therapeutic efficacy for MI. Methods: TUNEL assay and EdU assay were used to detect the effects of melatonin and miR-98 on H2O2-induced apoptosis and proliferation. MI model was used to evaluate the potential cardioprotective effects of melatonin and miR-98. Results: Melatonin attenuated H2O2-induced the proliferation reduction and apoptosis of c-kit+ CPCs in vitro, and CPCs which pretreated with melatonin significantly improved the functions of post-infarct hearts compared with CPCs alone in vivo. Melatonin was capable to inhibit the increase of miR-98 level by H2O2 in CPCs. The proliferation reduction and apoptosis of CPCs induced by H2O2 was aggravated by miR-98. In vivo, transplantation of CPCs with miR-98 silencing caused the more significant improvement of cardiac functions in MI than CPCs. MiR-98 targets at the signal transducer and activator of the transcription 3 (STAT3), and thus aggravated H2O2-induced the reduction of Bcl-2 protein. Conclusions: Pre-treatment with melatonin protects c-kit+ CPCs against oxidative stress-induced damage via downregulation of miR-98 and thereby increasing STAT3, representing a potentially new strategy to improve CPC-based therapy for MI.

Therapeutic efficiency of cardiac progenitor cells (CPCs) transplantation is limited by its low survival and retention in infarcted myocardium. Autophagy plays a critical role in regulating cell death and apoptosis, but the role of microRNAs (miRNAs) in oxidative stress-induced autophagy of CPCs remains unclear. This study aimed to explore if miRNAs mediate autophagy of c-kit+ CPCs. We found that the silencing of miR-143 promoted the autophagy of c-kit+ CPCs in response to H2O2, and the protective effect of miR-143 inhibitor was abrogated by autophagy inhibitor 3-methyladenine (3-MA). Furthermore, autophagy-related gene 7 (Atg7) was identified as the target gene of miR-143 by dual luciferase reporter assays. In vivo, after transfection with miR-143 inhibitor, c-kit+ CPCs from green fluorescent protein transgenic mice were more observed in infarcted mouse hearts. Moreover, transplantation of c-kit+ CPCs with miR-143 inhibitor improved cardiac function after myocardial infarction. Take together, our study demonstrated that miR-143 mediates oxidative stress-induced autophagy to enhance the survival of c-kit+ CPCs by targeting Atg7, which will provide a complementary approach for improving CPC-based heart repair. Keywords: Autophagy, Atg7, Cardiac progenitor cells, MicroRNAs, MI

Abstract In the past years, cardiac mortality has decreased, but cardiac diseases are still responsible for millions of deaths every year worldwide. Bone-marrow mesenchymal stem cells (BMSCs) transplantation may be a promising therapeutic strategy because of its capacity to differentiate into cardiac cells. Current research indicates that chemical substances, microRNAs, and cytokines have biological functions that regulate the cardiomyocytes differentiation of BMSCs. In this review, we chiefly summarize the regulatory factors that induce BMSCs to differentiate into cardiomyocytes.

Advances in developmental cardiology have increased our understanding of the early aspects of heart differentiation. However, understanding noncoding RNA (ncRNA) transcription and regulation during this process remains elusive. Here, we constructed transcriptomes for both long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in four important developmental stages ranging from early embryonic to cardiomyocyte based on high-throughput sequencing datasets, which indicate the high stage-specific expression patterns of two ncRNA types. Additionally, higher similarities of samples within each stage were found, highlighting the divergence of samples collected from distinct cardiac developmental stages. Next, we developed a method to identify numerous lncRNA and circRNA regulators whose expression was significantly stage-specific and shifted gradually and continuously during heart differentiation. We inferred that these ncRNAs are important for the stages of cardiac differentiation. Moreover, transcriptional regulation analysis revealed that the expression of stage-specific lncRNAs is controlled by known key stage-specific transcription factors (TFs). In addition, circRNAs exhibited dynamic expression patterns independent from their host genes. Functional enrichment analysis revealed that lncRNAs and circRNAs play critical roles in pathways that are activated specifically during heart differentiation. We further identified candidate TF-ncRNA-gene network modules for each differentiation stage, suggesting the dynamic organization of lncRNAs and circRNAs collectively controlled cardiac differentiation, which may cause heart-related diseases when defective. Our study provides a foundation for understanding the dynamic regulation of ncRNA transcriptomes during heart differentiation and identifies the dynamic organization of novel key lncRNAs and circRNAs to collectively control cardiac differentiation.

Background/Aims: Blue light emitting diodes (LEDs) have been proven to affect the growth of several types of cells. The effects of blue LEDs have not been tested on bone marrow-derived mesenchymal stem cells (BMSCs), which are important for cell-based therapy in various medical fields. Therefore, the aim of this study was to determine the effects of blue LED on the proliferation, apoptosis and osteogenic differentiation of BMSCs. Methods: BMSCs were irradiated with a blue LED light at 470 nm for 1 min, 5 min, 10 min, 30 min and 60 min or not irradiated. Cell proliferation was measured by performing cell counting and EdU staining assays. Cell apoptosis was detected by TUNEL staining. Osteogenic differentiation was evaluated by ALP and ARS staining. DCFH-DA staining and γ-H2A.X immunostaining were used to measure intracellular levels of ROS production and DNA damage. Results: Both cell counting and EdU staining assays showed that cell proliferation of BMSCs was significantly reduced upon blue LED irradiation. Furthermore, treatment of BMSCs with LED irradiation was followed by a remarkable increase in apoptosis, indicating that blue LED light induced toxic effects on BMSCs. Likewise, BMSC osteogenic differentiation was inhibited after exposure to blue LED irradiation. Further, blue LED irradiation was followed by the accumulation of ROS production and DNA damage. Conclusions: Taken together, our study demonstrated that blue LED light inhibited cell proliferation, inhibited osteogenic differentiation, and induced apoptosis in BMSCs, which are associated with increased ROS production and DNA damage. These findings may provide important insights for the application of LEDs in future BMSC-based therapies.

Background/Aims: Bone marrow-derived mesenchymal stem cells (BMSCs) have the ability to differentiate into multilineage cells such as osteoblasts, chondrocytes, and cardiomyocytes. Dysfunction of BMSCs in response to pathological stimuli participates in the development of diseases such as osteoporosis. Astragalus polysaccharide (APS) is a major active ingredient of Astragalus membranaceus, a commonly used anti-aging herb in traditional Chinese medicine. The aim of this study was to investigate whether APS protects against iron overload-induced dysfunction of BMSCs and its underlying mechanisms. Methods: BMSCs were exposed to ferric ammonium citrate (FAC) with or without different concentrations of APS. The viability and proliferation of BMSCs were assessed by CCK-8 assay and EdU staining. Cell apoptosis, senescence and pluripotency were examined utilizing TUNEL staining, β-galactosidase staining and qRT-PCR respectively. The reactive oxygen species (ROS) level was assessed in BMSCs with a DCFH-DA probe and MitoSOX Red staining. Results: Firstly, we found that iron overload induced by FAC markedly reduced the viability and proliferation of BMSCs, but treatment with APS at 10, 30 and 100 μg/mL was able to counter the reduction of cell proliferation. Furthermore, exposure to FAC led to apoptosis and senescence in BMSCs, which were partially attenuated by APS. The pluripotent genes Nanog, Sox2 and Oct4 were shown to be downregulated in BMSCs after FAC treatment, however APS inhibited the reduction of Nanog, Sox2 and Oct4 expression. Further study uncovered that APS treatment abrogated the increase of intracellular and mitochondrial ROS level in FAC-treated BMSCs. Conclusion: Treatment of BMSCs with APS to impede mitochondrial ROS accumulation can remarkably inhibit apoptosis, senescence, and the reduction of proliferation and pluripotency of BMSCs caused by FAC-induced iron overload.

The stem cell-based therapy has emerged as the promising therapeutic strategies for cardiovascular diseases (CVDs). Recently, increasing evidence suggest stem cell-derived active exosomes are important communicators among cells in the heart via delivering specific substances to the adjacent/distant target cells. These exosomes and their contents such as certain proteins, miRNAs and lncRNAs exhibit huge beneficial effects on preventing heart damage and promoting cardiac repair. More importantly, stem cell-derived exosomes are more effective and safer than stem cell transplantation. Therefore, administration of stem cell-derived exosomes will expectantly be an alternative stem cell-based therapy for the treatment of CVDs. Furthermore, modification of stem cell-derived exosomes or artificial synthesis of exosomes will be the new therapeutic tools for CVDs in the future. In addition, stem cell-derived exosomes also have been implicated in the diagnosis and prognosis of CVDs. In this review, we summarize the current advances of stem cell-derived exosome-based treatment and prognosis for CVDs, including their potential benefits, underlying mechanisms and limitations, which will provide novel insights of exosomes as a new tool in clinical therapeutic translation in the future.

Background/Aims: Low ambient temperature is an important risk factor for cardiovascular diseases, and has been shown to lead to cardiac hypertrophy. In this study, we aim to investigate if Resveratrol may inhibit cold exposure-induced cardiac hypertrophy in mice, and if so to clarify its molecular mechanism. Methods: Adult male mice were randomly assigned to Control group (kept at room temperature), Cold group (kept at low air temperature range from 3°C to 5°C) and Resveratrol treatment group (100mg/kg/day) for eight weeks. HE staining, Masson staining and Transmission electron microscopy were employed to detect cardiac structure, fibrosis and myocardial ultrastructure, respectively. Echocardiogram was used to measure myocardial functions. Western blot was used to detect the expression of MAPK pathway and apoptotic proteins. TUENL assay was performed to evaluate cardiomyocyte apoptosis. qRT-PCR was employed to measure the mRNA level. Results: Cold-treated mice showed a higher heart/body weight ratio and heart weight/tibia length ratio compared with control mice, and Resveratrol treatment may suppress these changes in cold-treated mice. Myocardial cross-section area and cardiac collagen volume were larger in cold group than control group, which also can be attenuated by Resveratrol treatment. Also, Resveratrol improved the ultrastructure damage of myocardium such as myofibril disarray in cold group. Echocardiogram measurement showed that EF and FS values in cold group declined apparently as compared to control group, and Resveratrol may improve the reduction of heart functions. The expression of p-JNK, p-p38 and p-ERK relative to total JNK, p38 and ERK in cold group was not altered in cold group and Resveratrol group as compared to control group. Cold-treated mouse hearts also showed the upregulation of hypertrophy-related miRNA-miR-328 but not miR-23a, and Resveratrol treatment can inhibit the increase of miR-328. Finally, Resveratrol treatment also may suppress apoptosis of myocardium in cold-treated mouse hearts via inhibiting Bax and caspase-3 activation. Conclusion: In summary, low ambient temperature can cause enlarged heart, ultrastructure damage of myocardium and weakened functions, and Resveratrol treatment effectively suppressed these changes at least partially via inhibiting cardiomyocyte apoptosis.

Background/Aims: Doxorubicin is a widely used chemotherapeutic agent, but its clinical use is restricted because of a high risk of cardiotoxicity. Bone marrow-derived mesenchymal stem cells (BMSCs) may repair ischaemically damaged myocardium through transdifferentiation and paracrine action. The aim of this study is to investigate if doxorubicin causes the apoptosis of BMSCs and in turn impairs its healing ability. Methods: BMSCs were exposed to doxorubicin, and cell apoptosis was determined by western blot and stainings. Results: Doxorubicin reduced the survival ratio and caused the apoptosis of BMSCs, with the increase of intracellular ROS level and depolarization of mitochondrial membrane potential. The ROS scavenger NAC abrogated these consequences. Moreover, doxorubicin markedly activated phosphorylated ERK, p38 and JNK proteins in BMSCs. The specific inhibitors for p38 (SB203580) and JNK (SP600125) may abolish doxorubicin-induced apoptosis of BMSCs but the specific ERK inhibitor (PD98059) not, indicating p38 and JNK activation contribute to BMSCs apoptosis. Also, the phosphorylated and total p53 proteins were increased in doxorubicin-treated BMSCs. Proapoptotic cleaved caspases-3 was upregulated and antiapoptotic Bcl-2 protein was reduced in doxorubicin-treated BMSCs. At last, ELISA assay showed that doxorubicin treatment reduced the VEGF and IGF-1 released by BMSCs. Conclusion: Taken together, doxorubicin caused BMSCs apoptosis associated with p38, JNK and p53 pathways.

Voltage-gated calcium currents and potassium currents were shown to undergo developmental changes in postnatal human and animal cardiomocytes. However, so far, there is no evidence whether sodium currents also presented the developmental changes in postnatal human atrial cells. The aim of this study was to observe age-related changes of sodium currents between pediatric and adult atrial myocytes. Human atrial myocytes were acutely isolated and the whole-cell patch clamp technique was used to record sodium currents isolated from pediatric and adult atrial cardiomocytes. The peak amplitude of sodium currents recorded in adult atrial cells was significantly larger than that in pediatric atrial myocytes. However, there was no significant difference of the activation voltage for peak sodium currents between two kinds of atrial myocytes. The time constants for the activation and inactivation of sodium currents were smaller in adult atria than pediatric atria. The further study revealed that the voltage-dependent inactivation of sodium currents were more slow in adult atrial cardiomyocytes than pediatric atrial cells. A significant difference was also observed in the recovery process of sodium channel from inactivation. In summary, a few significant differences were demonstrated in sodium currents characteristics between pediatric and adult atrial myocytes, which indicates that sodium currents in human atria also undergo developmental changes.

Bone marrow mesenchymal stem cells (BMSCs) are capable of homing to and repair damaged myocardial tissues. Apoptosis of BMSCs in response to various pathological stimuli leads to the attenuation of healing ability of BMSCs. Plenty of evidence has shown that elevated homocysteine level is a novel independent risk factor of cardiovascular diseases. The present study was aimed to investigate whether homocysteine may induce apoptosis of BMSCs and its underlying mechanisms. Here we uncovered that homocysteine significantly inhibited the cellular viability of BMSCs. Furthermore, TUNEL, AO/EB, Hoechst 333342 and Live/Death staining demonstrated the apoptotic morphological appearance of BMSCs after homocysteine treatment. A distinct increase of ROS level was also observed in homocysteine-treated BMSCs. The blockage of ROS by DMTU and NAC prevented the apoptosis of BMSCs induced by homocysteine, indicating ROS was involved in the apoptosis of BMSCs. Moreover, homocysteine also caused the depolarization of mitochondrial membrane potential of BMSCs. Furthermore, apoptotic appearance and mitochondrial membrane potential depolarization in homocysteine-treated BMSCs was significantly reversed by JNK inhibitor but not p38 MAPK and ERK inhibitors. Western blot also confirmed that p-JNK was significantly activated after exposing BMSCs to homocysteine. Homocysteine treatment caused a significant reduction of BMSCs-secreted VEGF and IGF-1 in the culture medium. Collectively, elevated homocysteine induced the apoptosis of BMSCs via ROS-induced the activation of JNK signal, which provides more insight into the molecular mechanisms of hyperhomocysteinemia-related cardiovascular diseases.

Background: Phototherapies based on sunlight, infrared, ultraviolet, visible, and laser-based treatments present advantages like high curative effects, small invasion, and negligible adverse reactions in cancer treatment. We aimed to explore the potential therapeutic effects of blue light emitting diode (LED) in human hepatoma cells and decipher the underlying cellular and molecular mechanisms. Methods: Wound healing and transwell assays were employed to probe the inhibition of the invasion and migration of hepatocellular carcinoma cells in the presence of blue LED. The sphere-forming test was used to evaluate the effect of LED blue light irradiation on cancer stem cell properties. Immunofluorescence and western blotting were used to detect the changes in γ-H2AX. The Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine staining, and colony formation assay were used to detect the combined effect of blue LED and sorafenib on cell proliferation inhibition. Results: We demonstrated that the irradiation of blue LED light in hepatoma cells could lead to cell proliferation reduction along with the increase of cell apoptosis. Simultaneously, blue LED irradiation also markedly suppressed the migration and invasion ability of human hepatoma cells. Sphere formation analysis further revealed the decreased cancer stemness of hepatoma cells upon blue LED irradiation. Mechanistically, blue LED irradiation significantly promoted the expression of the phosphorylation of the core histone protein H2AX (γ-H2AX), a sensitive molecular marker of DNA damage. In addition, we found that the combined treatment of blue LED irradiation and sorafenib increased cancer cell sensitivity to sorafenib. Conclusion: Collectively, we demonstrated that blue LED irradiation exhibited anti-tumor effects on liver cancer cells by inducing DNA damage and could enhance chemosensitivity of cancer cells, which represents a potential approach for human hepatoma treatment. [ABSTRACT FROM AUTHOR]

Introduction: While acute Coronavirus disease 2019 (COVID-19) affects the cardiovascular (CV) system according to recent data, an increased CV risk has been reported also during long-term follow-up (FU). In addition to other CV pathologies in COVID-19 survivors, an enhanced risk for arrhythmic events and sudden cardiac death (SCD) has been observed. While recommendations on postdischarge thromboprophylaxis are conflicting in this population, prophylactic short-term rivaroxaban therapy after hospital discharge showed promising results. However, the impact of this regimen on the incidence of cardiac arrhythmias has not been evaluated to date. Methods: To investigate the efficacy of this therapy, we conducted a single center, retrospective analysis of 1804 consecutive, hospitalized COVID-19 survivors between April and December 2020. Patients received either a 30-day postdischarge thromboprophylaxis treatment regimen using rivaroxaban 10 mg every day (QD) (Rivaroxaban group (Riva); n = 996) or no thromboprophylaxis (Control group (Ctrl); n = 808). Hospitalization for new atrial fibrillation (AF), newhigher-degree Atrioventricular-block (AVB) as well as incidence of SCD were investigated in 12-month FU [FU: 347 (310/449) days]. Results: No differences in baseline characteristics (Ctrl vs Riva: age: 59.0 (48.9/66.8) vs 57 (46.5/64.9) years, p = n.s.; male: 41.5% vs 43.7%, p = n.s.) and in the history of relevant CV-disease were observed between the two groups. While hospitalizations for AVB were not reported in either group, relevant rates of hospitalizations for new AF (0.99%, n = 8/808) as well as a high rate of SCD events (2.35%, n = 19/808) were seen in the Ctrl. These cardiac events were attenuated by early post-discharge prophylactic rivaroxaban therapy (AF: n = 2/996, 0.20%, p = 0.026 and SCD: n = 3/996, 0.30%, p < 0.001) which was also observed after applying a logistic regression model for propensity score matching (AF: χ2-statistics = 6.45, p = 0.013 and SCD: χ²-statistics = 9.33, p = 0.002). Of note, no major bleeding complications were observed in either group. Conclusion: Atrial arrhythmic and SCD events are present during the first 12 months after hospitalization for COVID-19. Extended prophylactic Rivaroxaban therapy after hospital discharge could reduce new onset of AF and SCD in hospitalized COVID-19 survivors. [ABSTRACT FROM AUTHOR]