METTL3-m6A methylation inhibits the proliferation and viability of type II alveolar epithelial cells in acute lung injury by enhancing the stability and translation efficiency of Pten mRNA.

BACKGROUND: The pathogenesis of acute lung injury (ALI) involves a severe inflammatory response, leading to significant morbidity and mortality. N6-methylation of adenosine (m6A), an abundant mRNA nucleotide modification, plays a crucial role in regulating mRNA metabolism and function. However, the precise impact of m6A modifications on the progression of ALI remains elusive. METHODS: ALI models were induced by either intraperitoneal injection of lipopolysaccharide (LPS) into C57BL/6 mice or the LPS-treated alveolar type II epithelial cells (AECII) in vitro. The viability and proliferation of AECII were assessed using CCK-8 and EdU assays. The whole-body plethysmography was used to record the general respiratory functions. M6A RNA methylation level of AECII after LPS insults was detected, and then the "writer" of m6A modifications was screened. Afterwards, we successfully identified the targets that underwent m6A methylation mediated by METTL3, a methyltransferase-like enzyme. Last, we evaluated the regulatory role of METTL3-medited m6A methylation at phosphatase and tensin homolog (Pten) in ALI, by assessing the proliferation, viability and inflammation of AECII. RESULTS: LPS induced marked damages in respiratory functions and cellular injuries of AECII. The m6A modification level in mRNA and the expression of METTL3, an m6A methyltransferase, exhibited a notable rise in both lung tissues of ALI mice and cultured AECII cells subjected to LPS treatment. METTL3 knockdown or inhibition improved the viability and proliferation of LPS-treated AECII, and also reduced the m6A modification level. In addition, the stability and translation of Pten mRNA were enhanced by METTL3-mediated m6A modification, and over-expression of PTEN reversed the protective effect of METTL3 knockdown in the LPS-treated AECII. CONCLUSIONS: The progression of ALI can be attributed to the elevated levels of METTL3 in AECII, as it promotes the stability and translation of Pten mRNA through m6A modification. This suggests that targeting METTL3 could offer a novel approach for treating ALI.

POLR1D silencing suppresses lung cancer cells proliferation and migration via inhibition of PI3K-Akt pathway.

AIM: The most common type of cancer that leads to death worldwide is lung cancer. Despite significant surgery and chemotherapy improvements, lung cancer patient's survival rate is still poor. The RNA polymerase I subunit D (POLR1D) gene can induce various cancers. A current study reported that POLR1D plays a vital role in cancer prognosis. However, its biological function in the development of lung cancer remains unclear. METHODS: Reverse transcription PCR (RT-PCR) measured the relative POLR1D protein expression level in lung cancer cell lines. Lung cancer cell proliferation, migration, and invasion were analyzed by performing cell counting kit-8 (CCK-8), and transwell. The phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/AKT) signaling pathway-related protein expressions were examined by Western blotting assay. RESULTS: POLR1D protein expression was elevated in lung cancer. Lung cancer cell loss-of-function tests showed that POLR1D silencing could attenuate cell viability both in SK-MES-1 and in H2170 cells. Furthermore, silencing POLR1D inhibited SK-MES-1 and H2170 cells proliferation, migration, and invasion. Moreover, SK-MES-1 and H2170 cells' migration and invasion capacity were potentially suppressed by the knockdown of POLR1D. The progression of multiple cancers has been implicated in the PI3K/AKT pathway. Here, we observed that POLR1D silencing suppressed lung cancer progression by inhibition of the PI3K-Akt pathway. CONCLUSIONS: The study speculated that POLR1D might provide a new potential therapeutic possibility for treating lung cancer patients via targeting PI3K/AKT.

Methylprednisolone alleviates lung injury in sepsis by regulating miR-151-5p/USP38 pathway.

BACKGROUND: Acute lung injury (ALI) is manifested by increased blood vessel permeability within the lungs and subsequent impairment of alveolar gas exchange. Methylprednisolone (MP) is commonly used as a treatment for ALI to reduce inflammation, yet its molecular mechanism remains unclear. This study aims to explore the underlying mechanisms of MP on ALI in a model induced by lipopolysaccharide (LPS). MATERIAL AND METHODS: The proliferation, viability, apoptosis, and miR-151-5p expression of alveolar type II epithelial cells (AECII) were detected using the cell EdU assay, Annexin V/PI Apoptosis Kit, counting kit-8 (CCK-8) assay, and RT-qPCR. Western blot analysis was used to detect the Usp38 protein level. IL-6 and TNF-α were measured by ELISA. The combination of miR-151-5p and USP38 was determined by chromatin immunoprecipitation (ChIP)-PCR and dual-luciferase reporter assay. RESULTS: MP greatly improved pulmonary function in vivo, reduced inflammation, and promoted the proliferation of the alveolar type II epithelial cells (AECII) in vitro. By comparing the alterations of microRNAs in lung tissues between MP treatment and control groups, we found that miR-151-5p exhibited a significant increase after LPS-treated AECII, but decreased after MP treatment. Confirmed by a luciferase reporter assay, USP38, identified as a downstream target of miR-151-5p, was found to increase after MP administration. Inhibition of miR-151-5p or overexpression of USP38 in AECII significantly improved the anti-inflammatory, anti-apoptotic, and proliferation-promotive effects of MP. CONCLUSION: In summary, our data demonstrated that MP alleviates the inflammation and apoptosis of AECII induced by LPS, and promotes the proliferation of AECII partially via miR-151-5p suppression and subsequent USP38 activation.

Machine learning reveals ferroptosis features and a novel ferroptosis classifier in patients with sepsis.

OBJECTIVE: Sepsis is an organ malfunction disease that may become fatal and is commonly accompanied by severe complications such as multiorgan dysfunction. Patients who are already hospitalized have a high risk of death due to sepsis. Even though early diagnosis is very important, the technology and clinical approaches that are now available are inadequate. Hence, there is an immediate necessity to investigate biological markers that are sensitive, specific, and reliable for the prompt detection of sepsis to reduce mortality and improve patient prognosis. Mounting research data indicate that ferroptosis contributes to the occurrence, development, and prevention of sepsis. However, the specific regulatory mechanism of ferroptosis remains to be elucidated. This research evaluated the expression profiles of ferroptosis-related genes (FRGs) and the diagnostic significance of the ferroptosis-related classifiers in sepsis. METHODS AND RESULTS: We collected three peripheral blood data sets from septic patients, integrated the clinical examination data and mRNA expression profile of these patients, and identified 13 FRGs in sepsis through a co-expression network and differential analysis. Then, an optimal classifier tool for sepsis was constructed by integrating a variety of machine learning algorithms. Two key genes, ATG16L1 and SRC, were shown to be shared between the algorithms, and thus were identified as the FRG signature of classifier. The tool exhibited satisfactory diagnostic efficiency in the training data set (AUC = 0.711) and two external verification data sets (AUC = 0.961; AUC = 0.913). In the rat cecal ligation puncture sepsis model, in vivo experiments verified the involvement of ATG16L1 and SRC in the early sepsis process. CONCLUSION: These findings confirm that FRGs may participate in the development of sepsis, the ferroptosis related classifiers can provide a basis for the development of new strategies for the early diagnosis of sepsis and the discovery of new potential therapeutic targets for life-threatening infections.

Irf7 regulates the expression of Srg3 and ferroptosis axis aggravated sepsis-induced acute lung injury.

OBJECTIVE: To investigate the mechanism of action of Srg3 in acute lung injury caused by sepsis. METHODS: First, a sepsis-induced acute lung injury rat model was established using cecal ligation and puncture (CLP). RNA sequencing (RNA-seq) was used to screen for highly expressed genes in sepsis-induced acute lung injury (ALI), and the results showed that Srg3 was significantly upregulated. Then, SWI3-related gene 3 (Srg3) was knocked down using AAV9 vector in vivo, and changes in ALI symptoms in rats were analyzed. In vitro experiments were conducted by establishing a cell model using lipopolysaccharide (LPS)-induced BEAS-2B cells and coculturing them with phorbol 12-myristate 13-acetate (PMA)-treated THP-1 cells to analyze macrophage polarization. Next, downstream signaling pathways regulated by Srg3 and transcription factors involved in regulating Srg3 expression were analyzed using the KEGG database. Finally, gain-of-loss functional validation experiments were performed to analyze the role of downstream signaling pathways regulated by Srg3 and transcription factors involved in regulating Srg3 expression in sepsis-induced acute lung injury. RESULTS: Srg3 was significantly upregulated in sepsis-induced acute lung injury, and knocking down Srg3 significantly improved the symptoms of ALI in rats. Furthermore, in vitro experiments showed that knocking down Srg3 significantly weakened the inhibitory effect of LPS on the viability of BEAS-2B cells and promoted alternative activation phenotype (M2) macrophage polarization. Subsequent experiments showed that Srg3 can regulate the activation of the NF-κB signaling pathway and promote ferroptosis. Specific activation of the NF-κB signaling pathway or ferroptosis significantly weakened the effect of Srg3 knockdown. It was then found that Srg3 can be transcriptionally activated by interferon regulatory factor 7 (Irf7), and specific inhibition of Irf7 significantly improved the symptoms of ALI. CONCLUSIONS: Irf7 transcriptionally activates the expression of Srg3, which can promote ferroptosis and activate classical activation phenotype (M1) macrophage polarization by regulating the NF-κB signaling pathway, thereby exacerbating the symptoms of septic lung injury.

Long-term SARS-CoV-2 neutralizing antibody level prediction using multimodal deep learning: A prospective cohort study on longitudinal data in Wuhan, China.

The ongoing epidemic of SARS-CoV-2 is taking a substantial financial and health toll on people worldwide. Assessing the level and duration of SARS-CoV-2 neutralizing antibody (Nab) would provide key information for government to make sound healthcare policies. Assessed at 3-, 6-, 12-, and 18-month postdischarge, we described the temporal change of IgG levels in 450 individuals with moderate to critical COVID-19 infection. Moreover, a data imputation framework combined with a novel deep learning model was implemented to predict the long-term Nab and IgG levels in these patients. Demographic characteristics, inspection reports, and CT scans during hospitalization were used in this model. Interpretability of the model was further validated with Shapely Additive exPlanation (SHAP) and Gradient-weighted Class Activation Mapping (GradCAM). IgG levels peaked at 3 months and remained stable in 12 months postdischarge, followed by a significant decline in 18 months postdischarge. However, the Nab levels declined from 6 months postdischarge. By training on the cohort of 450 patients, our long-term antibody prediction (LTAP) model could predict long-term IgG levels with relatively high area under the receiver operating characteristic curve (AUC), accuracy, precision, recall, and F1-score, which far exceeds the performance achievable by commonly used models. Several prognostic factors including FDP levels, the percentages of T cells, B cells and natural killer cells, older age, sex, underlying diseases, and so forth, served as important indicators for IgG prediction. Based on these top 15 prognostic factors identified in IgG prediction, a simplified LTAP model for Nab level prediction was established and achieved an AUC of 0.828, which was 8.9% higher than MLP and 6.6% higher than LSTM. The close correlation between IgG and Nab levels making it possible to predict long-term Nab levels based on the factors selected by our LTAP model. Furthermore, our model identified that coagulation disorders and excessive immune response, which indicate disease severity, are closely related to the production of IgG and Nab. This universal model can be used as routine discharge tests to identify virus-infected individuals at risk for recurrent infection and determine the optimal timing of vaccination for general populations.

Lower Serum Angiotensin-Converting Enzyme Level in Relation to Hyperinflammation and Impaired Antiviral Immune Response Contributes to Progression of COVID-19 Infection.

INTRODUCTION: As a homologue of the angiotensin-converting enzyme (ACE), angiotensin-converting enzyme 2 (ACE2) has been identified as the main receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) invasion. We aimed to investigate the role of serum ACE in predicting the coronavirus disease 2019 (COVID-19) disease progression and the underlying mechanisms. METHODS: We retrospectively enrolled 120 patients with confirmed COVID-19 who underwent serum ACE detection on admission. The clinical characteristics and laboratory findings during hospitalization were evaluated dynamically to identify the potential risk factors for disease progression. RESULTS: ACE level was demonstrated as one of the independent risk factors. Patients with ACE level ≤ 33.5 U/L showed a higher cumulative virus RNA detection rate, elevated pro-inflammatory mediators levels, declined lymphocyte count, and decreased SARS-CoV-2-specific antibodies than those with ACE level > 33.5 U/L. CONCLUSION: Lower serum ACE levels in relation to delayed virus elimination, hyperinflammatory condition, and impaired host antiviral immune responses contribute to disease progression of COVID-19.

Local intramyocardial delivery of bioglass with alginate hydrogels for post-infarct myocardial regeneration.

Heart failure (HF) is a common and serious manifestation after myocardial infarction (MI). Despite their clinical importance, current treatments for MI still have several limitations. Revascularization has been proven to have positive effects on MI-induced damage. Currently biomaterial-based angiogenesis strategies represent potential candidates for MI treatment. Bioglass (BG) is a commercially available family of bioactive glasses. BG has angiogenic properties and thus might be an attractive alternative for MI treatments. Here, we loaded BG in sodium alginate (BGSA), locally injected it into peri-infarct myocardial tissue and examined its suitability for inducing cardiac angiogenesis and eventually improving cardiac function following MI. Cardiac function was evaluated via echocardiography. Infarct morphometry, angiogenesis, apoptosis and angiogenic protein expression were all analysed 4 weeks after BGSA injection. Compared with the control treatment, BGSA was sufficient to prompt angiogenesis, suppress apoptosis, up-regulate the expression of angiogenic proteins, attenuate infarct size, preserve wall thickness and eventually improve cardiac function. Our results demonstrate the feasibility and effectiveness of BGSA in myocardial regeneration via angiogenesis, suggesting that BGSA is a potential therapeutic strategy for post-infarct myocardial regeneration.

Pericardial fluid levels of growth differentiation factor 15 in patients with or without coronary artery disease: a prospective study.

BACKGROUND: Growth differentiation factor 15 (GDF15) has already been reported as a novel efficient biomarker in patients with coronary artery diseases (CAD). However, very little is demonstrated about the potential impact of pericardial fluid GDF-15 accumulation on CAD. The aim of this study was to evaluate pericardial fluid and plasma GDF15 levels in patients with ischemic heart disease. METHODS: In this study, 42 consecutive patients (21 patients with significant CAD; 21 patients without CAD) undergoing open heart surgery were recruited in this study. Pericardial fluid were obtained at the time of surgery, and GDF15 levels in the samples were measured by enzyme-linked immunosorbent assay. Plasma glucose, creatinine, CK-MB, cTnI and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements were performed. RESULTS: The plasma GDF15 levels were markedly higher than the pericardial fluid levels both in the CAD group and non-CAD group (1,174.0±148.7 vs. 677.8±77.2 pg/mL, P<0.01; 925.8±127.4 vs. 617.4±76.2 pg/mL, P<0.01). The levels of pericardial fluid GDF15, was not statistically different between the CAD and non-CAD groups (P>0.05). An obvious correlation was observed between plasma and pericardial fluid GDF15 concentration both in the CAD group and non-CAD group (R=0.53, P<0.01; R=0.54, P<0.01). An obvious positive correlation was found between pericardial fluid GDF15 and plasma creatinine levels in CAD patients but not in non-CAD patients (R=0.65, P<0.01). In the CAD group, an obvious correlation was also observed between pericardial fluid GDF15 levels and NT-ProBNP (R=0.63, P<0.01), while no relationship was found in non-CAD group. There was a positive correlation between pericardial fluid GDF15 and LVEF in non-CAD group but not in CAD group patients (R=-0.44, P<0.05). CONCLUSIONS: Our study first revealed an association between pericardial fluid GDF15 and baseline characteristics. Pericardial fluid GDF15 levels are associated with cardiac and kidney function in patients with coronary artery disease and may be a valuable marker for assessing CAD severity and predicting its complications.

Quantitative flow ratio-guided surgical intervention in symptomatic myocardial bridging.

BACKGROUND: Patients with myocardial bridging (MB) are associated with adverse cardiovascular events, but a decision to perform surgical intervention, especially for patients with systolic intermediate stenosis, is a difficult clinical issue. Fractional flow reserve (FFR) represents a novel method for the functional evaluation of coronary stenosis, but the relationship between FFR and MB remains controversial because of the cyclic dynamic stenosis of MB. Quantitative flow ratio (QFR) is a novel index allowing fast assessment of FFR from a diagnostic coronary angiography. This study aimed to investigate the relationship between QFR and MB patients and to further develop a prediction model of QFR-guided surgical intervention for these patients. METHODS: Forty-five symptomatic lone MB patients who had undergone coronary angiography were consecutively enrolled in this study. MB was located in the middle of left anterior descending artery with intermediate stenosis during systole. The patients were retrospectively divided into a medical therapy group or a surgical therapy group. Systolic geometry based QFR (SG-QFR) and diastolic geometry based QFR (DG-QFR) were calculated based on three-dimensional quantitative coronary angiography and patient-specific flow velocity. Subsequently, time-averaged QFR (TA-QFR) is defined as the average of SG-QFR and DG-QFR. RESULTS: Receiver operating characteristic curve analysis revealed that TA-QFR (AUC = 0.91; 95% CI: 0.79-0.98) was found to be the best pre-operative index for surgical intervention to MB, when compared with DG-QFR (AUC = 0.69; 95% CI: 0.53-0.82; difference: 0.22; 95% CI: 0.04-0.41; p = 0.02) and SG-QFR (AUC = 0.87; 95% CI: 0.74-0.95; difference: 0.04; 95% CI: 0.00-0.08; p = 0.03). CONCLUSIONS: TA-QFR improved the performance of functional evaluation in MB patients with intermediate stenosis during systole and is useful for guiding surgical intervention.

Injectable Citrate-Based Hydrogel as an Angiogenic Biomaterial Improves Cardiac Repair after Myocardial Infarction.

Implanted medical biomaterials are closely in contact with host biological systems via biomaterial-cell/tissue interactions, and these interactions play pivotal roles in regulating cell functions and tissue regeneration. However, many biomaterials degrade over time, and these degradation products also have been shown to interact with host cells/tissue. Therefore, it may prove useful to specifically design implanted biomaterials with degradation products which greatly improve the performance of the implant. Herein, we report an injectable, citrate-containing polyester hydrogel which can release citrate as a cell regulator via hydrogel degradation and simultaneously show sustained release of an encapsulated growth factor Mydgf. By coupling the therapeutic effect of the hydrogel degradation product (citrate) with encapsulated Mydgf, we observed improved postmyocardial infarction (MI) heart repair in a rat MI model. Intramyocardial injection of our Mydgf-loaded citrate-containing hydrogel was shown to significantly reduce scar formation and infarct size, increase wall thickness and neovascularization, and improve heart function. This bioactive injectable hydrogel-mediated combinatorial approach offers myriad advantages including potential adjustment of delivery rate and duration, improved therapeutic effect, and minimally invasive administration. Our rational design combining beneficial degradation product and controlled release of therapeutics provides inspiration toward the next generation of biomaterials aiming to revolutionize regenerative medicine.

Elastic 3D-Printed Hybrid Polymeric Scaffold Improves Cardiac Remodeling after Myocardial Infarction.

Myocardial remodeling, including ventricular dilation and wall thinning, is an important pathological process caused by myocardial infarction (MI). To intervene in this pathological process, a new type of cardiac scaffold composed of a thermoset (poly-[glycerol sebacate], PGS) and a thermoplastic (poly-[ε-caprolactone], PCL) is directly printed by employing fused deposition modeling 3D-printing technology. The PGS-PCL scaffold possesses stacked construction with regular crisscrossed filaments and interconnected micropores and exhibits superior mechanical properties. In vitro studies demonstrate favorable biodegradability and biocompatibility of the PGS-PCL scaffold. When implanted onto the infarcted myocardium, this scaffold improves and preserves heart function. Furthermore, the scaffold improves several vital aspects of myocardial remodeling. On the morphological level, the scaffold reduces ventricular wall thinning and attenuated infarct size, and on the cellular level, it enhances vascular density and increases M2 macrophage infiltration, which might further contribute to the mitigated myocardial apoptosis rate. Moreover, the flexible PGS-PCL scaffold can be tailored to any desired shape, showing promise for annular-shaped restraint device application and meeting the demands for minimal invasive operation. Overall, this study demonstrates the therapeutic effects and versatile applications of a novel 3D-printed, biodegradable and biocompatible cardiac scaffold, which represents a promising strategy for improving myocardial remodeling after MI.

Human Neonatal Thymus Mesenchymal Stem/Stromal Cells and Chronic Right Ventricle Pressure Overload.

Right ventricle (RV) failure secondary to pressure overload is associated with a loss of myocardial capillary density and an increase in oxidative stress. We have previously found that human neonatal thymus mesenchymal stem cells (ntMSCs) promote neovascularization, but the ability of ntMSCs to express the antioxidant extracellular superoxide dismutase (SOD3) is unknown. We hypothesized that ntMSCs express and secrete SOD3 as well as improve survival in the setting of chronic pressure overload. To evaluate this hypothesis, we compared SOD3 expression in ntMSCs to donor-matched bone-derived MSCs and evaluated the effect of ntMSCs in a rat RV pressure overload model induced by pulmonary artery banding (PAB). The primary outcome was survival, and secondary measures were an echocardiographic assessment of RV size and function as well as histological studies of the RV. We found that ntMSCs expressed SOD3 to a greater degree as compared to bone-derived MSCs. In the PAB model, all ntMSC-treated animals survived to the study endpoint whereas control animals had significantly decreased survival. Treatment animals had significantly less RV fibrosis and increased RV capillary density as compared to controls. We conclude that human ntMSCs demonstrate a therapeutic effect in a model of chronic RV pressure overload, which may in part be due to their antioxidative, antifibrotic, and proangiogenic effects. Given their readily available source, human ntMSCs may be a candidate cell therapy for individuals with congenital heart disease and a pressure-overloaded RV.

Advanced glycation end products of bovine serum albumin affect the cell growth of human umbilical vein endothelial cells via modulation of MEG3/miR-93/p21 pathway.

Advanced glycation end products of BSA (AGE-BSA) contribute to the pathogenesis of diabetic vascular diseases. However, the roles and underlying mechanisms of AGE-BSA in diabetic vascular diseases remain largely unclear. Long non-coding RNAs (lncRNAs) are widely identified and known as gene regulators. However, the roles of lncRNAs in diabetic vascular disease are still vague. In this study, we sought to investigate the contributions of lncRNAs in human umbilical vein endothelial cells (HUVECs) treated with AGE-BSA. We first demonstrated that AGE-BSA reduced the cell viability and inhibited the cell proliferation of HUVECs. Then, we found that lncRNA MEG3 was up-regulated in HUVECs treated with AGE-BSA. Furthermore, inhibition of MEG3 restored the AGE-BSA-induced repression of cell viability and proliferation. In addition, our results revealed that MEG3 played its role via modulation of miR-93 expression in HUVECs treated with AGE-BSA. Furthermore, we illustrated that miR-93 played its role via regulation of p21 in HUVECs treated with AGE-BSA. Ultimately, our study displayed that AGE-BSA exerted its function via modulation of MEG3/miR-93/p21 pathway in HUVECs. Thus, for the first time, we identified the MEG3/miR-93/p21 axis in HUVECs treated with AGE-BSA, which might be a novel regulatory network in diabetic vascular cells, and possess the potential therapeutic value for diabetes mellitus.

Human Neonatal Thymus Mesenchymal Stem Cells Promote Neovascularization and Cardiac Regeneration.

Newborns with critical congenital heart disease are at significant risk of developing heart failure later in life. Because treatment options for end-stage heart disease in children are limited, regenerative therapies for these patients would be of significant benefit. During neonatal cardiac surgery, a portion of the thymus is removed and discarded. This discarded thymus tissue is a good source of MSCs that we have previously shown to be proangiogenic and to promote cardiac function in an in vitro model of heart tissue. The purpose of this study was to further evaluate the cardiac regenerative and protective properties of neonatal thymus (nt) MSCs. We found that ntMSCs expressed and secreted the proangiogenic and cardiac regenerative morphogen sonic hedgehog (Shh) in vitro more than patient-matched bone-derived MSCs. We also found that organoid culture of ntMSCs stimulated Shh expression. We then determined that ntMSCs were cytoprotective of neonatal rat cardiomyocytes exposed to H2O2. Finally, in a rat left coronary ligation model, we found that scaffoldless cell sheet made of ntMSCs applied to the LV epicardium immediately after left coronary ligation improved LV function, increased vascular density, decreased scar size, and decreased cardiomyocyte death four weeks after infarction. We conclude that ntMSCs have cardiac regenerative properties and warrant further consideration as a cell therapy for congenital heart disease patients with heart failure.

17ß-estradiol promotes recovery after myocardial infarction by enhancing homing and angiogenic capacity of bone marrow-derived endothelial progenitor cells through ERα-SDF-1/CXCR4 crosstalking.

17ß-estradiol (E2) has been shown to mediate endothelial progenitor cells (EPCs) to repair infarcted myocardium. Both estrogen receptor α (ERα) and stromal derived factor-1 (SDF-1)/CXCR4 signaling pathways may play a critical role in regulating homing and angiogenesis of EPCs in this process. However, the interaction between ERα and SDF-1/CXCR4 signaling pathways remains unclear. In response to E2, the expression of SDF-1 and CXCR4 in EPCs from ovariectomized BALB/C mice was obviously up-regulated, in addition, the migration and tube formation of EPCs in vitro were also significantly enhanced. However, ERα antagonist (MMP) and CXCR4 inhibitor (AMD3100) significantly decreased the migration and tube length of EPCs, even if mediated by E2. The combined treatment of MMP and AMD3100 exerted more inhibitory effects on migration and tube formation of EPCs induced by E2. In in vivo studies, ovariectomized mice were induced acute myocardial infarction (AMI), and divided into four groups (n = 6): non-preconditioned EPCs (3 × 106) group, E2-preconditioned EPCs group, MMP + AMD3100 preconditioned EPCs group, and EPCs pretreated with E2 + MMP + AMD3100 group. E2 group displayed a greater number of homing EPCs, increased capillary density in infarcted myocardium, decreased left ventricular (LV) fibrosis. Nevertheless, these effects of E2 were almost completely blocked by the combined treatment of MMP and AMD3100. E2 can produce cardiovascular protective effects in AMI setting by enhancing homing and angiogenic capacity of EPCs through ERα and CXCR4 signaling pathways, which means that ERα and CXCR4 pathways are effective targets for the development of treatment strategies for AMI.

Long non-coding RNA H19 contributes to hypoxia-induced CPC injury by suppressing Sirt1 through miR-200a-3p.

Cardiomyocyte death is the chief obstacle that prevents the heart function recovery in myocardial infarction (MI)-induced heart failure (HF). Cardiac progenitor cells (CPCs)-based myocardial regeneration has provided a promising method for heart function recovery after MI. However, CPCs can easily lose their proliferation ability due to oxygen deficiency in infarcted myocardium. Revealing the underlying molecular mechanism for CPC proliferation is critical for effective MI therapy. In the present study, we set up a CoCl2-induced hypoxia model in CPCs. We found that the expression of long non-coding RNA H19 was significantly down-regulated in CPCs after hypoxia stimuli. In addition, H19 suppression attenuated the proliferation and migration of CPCs under hypoxia stress. Furthermore, we discovered that H19 regulated the proliferation and migration of CPCs through mediating the expression of Sirt1 which is a target of miR-200a-3p under hypoxia. In conclusion, our findings demonstrate a novel regulatory mechanism for the proliferation and migration of CPCs under hypoxia condition, which provides useful information for the development of new therapeutic targets for MI therapy.

LncRNA-MALAT1 promotes CPC proliferation and migration in hypoxia by up-regulation of JMJD6 via sponging miR-125.

The death of cardiomyocytes after myocardial infarction (MI) often leads to ventricular remodeling as well as heart failure (HF). The cardiac progenitor cells (CPCs) have the ability to regenerate functional heart muscle in patients after MI, which provides a promising method for MI-induced HF therapy. However, to date, CPCs can easily lose their proliferation ability in the infarcted myocardium. Therefore, exploring the mechanism for CPC proliferation is essential for CPC-based therapy in MI-induced HF. A previous study indicated that a hypoxic environment is essential for CPC proliferation, but the mechanism is not yet clear. In this work, we discovered that CoCl2-induced hypoxia can promote CPC proliferation and migration. Additionally, long non-coding RNA MALAT1 expression was significantly up-regulated in the CoCl2-induced hypoxia CPC model. MALAT1 suppression inhibited CPC proliferation and migration under hypoxic conditions. In addition, MALAT1 acted as a sponge for miR-125. The miR-125 inhibitor restored the proliferation and migration potentials of CPCs after a MALAT1 knockdown in hypoxia. A further study demonstrated that JMJD6 was a target of miR-125 whose expression was negatively regulated by miR-125. JMJD6 knockdown blocked miR-125 inhibitor's protective effect on CPC function in hypoxia. Ultimately, our finding demonstrated that MALAT1 can modulate CPC proliferation and migration potential through the miR-125/JMJD6 axis in hypoxia. Our finding provided a new regulatory mechanism for CPC proliferation in hypoxia, which provided a new target for MI-induced HF therapy.

MicroRNA-532 protects the heart in acute myocardial infarction, and represses prss23, a positive regulator of endothelial-to-mesenchymal transition.

AIMS: Acute myocardial infarction (MI) leads to cardiac remodelling and development of heart failure. Insufficient myocardial capillary density after MI is considered a critical determinant of this process. MicroRNAs (miRs), negative regulators of gene expression, have emerged as important players in MI. We previously showed that miR-532-5p (miR-532) is up-regulated by the ß-arrestin-biased ß-adrenergic receptor antagonist (ß-blocker) carvedilol, which activates protective pathways in the heart independent of G protein-mediated second messenger signalling. Here, we hypothesize that ß2-adrenergic receptor/ß-arrestin-responsive miR-532 confers cardioprotection against MI. METHODS AND RESULTS: Using cultured cardiac endothelial cell (CEC) and in vivo approaches, we show that CECs lacking miR-532 exhibit increased transition to a fibroblast-like phenotype via endothelial-to-mesenchymal transition (EndMT), while CECs over-expressing miR-532 display decreased EndMT. We also demonstrate that knockdown of miR-532 in mice causes abnormalities in cardiac structure and function as well as reduces CEC proliferation and cardiac vascularization after MI. Mechanistically, cardioprotection elicited by miR-532 is in part attributed to direct repression of a positive regulator of maladaptive EndMT, prss23 (a protease serine 23) in CECs. CONCLUSIONS: In conclusion, these findings reveal a pivotal role for miR-532-prss23 axis in regulating CEC function after MI, and this novel axis could be suitable for therapeutic intervention in ischemic heart disease.