New aspects of the epigenetic regulation of EMT related to pulmonary fibrosis.

Pulmonary fibrosis is a chronic and progressive fibrotic disease that results in impaired gas exchange, ventilation, and eventual death. The pro-fibrotic environment is instigated by various factors, leading to the transformation of epithelial cells into myofibroblasts and/or fibroblasts that trigger fibrosis. Epithelial mesenchymal transition (EMT) is a biological process that plays a critical role in the pathogenesis of pulmonary fibrosis. Epigenetic regulation of tissue-stromal crosstalk involving DNA methylation, histone modifications, non-coding RNA, and chromatin remodeling plays a key role in the control of EMT. The review investigates the epigenetic regulation of EMT and its significance in pulmonary fibrosis.

IGFBP3 epigenetic promotion induced by METTL3 boosts cardiac fibroblast activation and fibrosis.

Cardiac fibrosis remains an unresolved problem in heart disease. Its etiology is directly caused by the activation and proliferation of cardiac fibroblasts (CFs). However, there is limited information regarding the biological role of cardiac fibroblasts in cardiac fibrosis. Herein, we screened out a gene, IGFBP3, whose expression significantly increased in TGF-ß1-stimulated human primary CFs by mining RNA-Seq data for differential and WGCNA. We verified the IGFBP3's expression in transverse aortic constriction (TAC) surgery, isoproterenol (ISO)-induced cardiac fibrosis models, and TGFß1-stimulated mouse primary CFs. We also found that the knockdown of IGFBP3 could inhibit the migration and proliferation ability of CFs. Furthermore, we found that aberrant N6-methyladenosine(m6A) mRNA modifications in the animal model and activated CFs may regulate the expression of IGFBP3 in developing cardiac fibrosis. Silencing METTL3 could downregulate the expression of IGFBP3 and inhibit the activation of CFs and the degree of cardiac fibrosis both in vitro and in vivo. Indeed, we also verified the expression of METTL3 and IGFBP3 in the atrial tissues of patients with atrial fibrillation (AF). Thus, METTL3 may regulate IGFBP3's expression and CFs activation via RNA epigenetic modifications, laying the foundation for a specific and novel therapeutic target in cardiac fibrosis.

Epigenetic control of LncRNA NEAT1 enables cardiac fibroblast pyroptosis and cardiac fibrosis.

Cardiac fibroblasts (CFs) drive extracellular matrix remodeling after inflammatory injury, leading to cardiac fibrosis and diastolic dysfunction. Recent studies described the role of epigenetics in cardiac fibrosis. Nevertheless, detailed reports on epigenetics regulating CFs pyroptosis and describing their implication in cardiac fibrosis are still unclear. Here, we found that DNMT3A reduces the expression of lncRNA Neat1 and promotes the NLRP3 axis leading to CFs pyroptosis, using cultured cells, animal models, and clinical samples to shed light on the underlying mechanism. We report that pyroptosis-related genes are increased explicitly in cardiac fibrosis tissue and LPS-treated CFs, while lncRNA Neat1 decreased. Mechanistically, we show that loss of DNMT3A or overexpression of lncRNA Neat1 in CFs after LPS treatment significantly enhances CFs pyroptosis and the production of pyroptosis-related markers in vitro. It has been demonstrated that DNMT3A can decrease lncRNA Neat1, promoting NLRP3 axis activation in CFs treated with LPS. In sum, this study is the first to identify that DNMT3A methylation decreases the expression of lncRNA Neat1 and promotes CFs pyroptosis and cardiac fibrosis, suggesting that DNMT3A and NEAT1 may function as an anti-fibrotic therapy target in cardiac fibrosis.

DNMT1-Induced miR-152-3p Suppression Facilitates Cardiac Fibroblast Activation in Cardiac Fibrosis.

Novel insights into epigenetic control of cardiac fibrosis are now emerging. Cardiac fibroblasts (CFs) activation into myofibroblasts and the production of extracellular matrix (ECM) is the key to cardiac fibrosis development, but the specific mechanism is not fully understood. In the present study, we found that DNMT1 hypermethylation reduces the expression of microRNA-152-3p (miR-152-3p) and promotes Wnt1/ß-catenin signaling pathway leading to CFs proliferation and activation. Cardiac fibrosis was produced by ISO, and the ISO was carried out according to the method described. CFs were harvested and cultured from SD neonatal rats and stimulated with TGF-ß1. Importantly, DNMT1 resulted in the inhibition of miR-152-3p in activated CFs and both DNMT1 and miR-152-3p altered Wnt/ß-catenin downstream protein levels. Over expression of DNMT1 and miR-152-3p inhibitors promotes proliferation of activating CFs. In addition, decreased methylation levels and over expression of miR-152-3p inhibited CFs proliferation. We determined that DNMT1 can methylate to miR-152-3p and demonstrated that expression of miR-152-3p inhibits CFs proliferation by inhibiting the Wnt1/ß-catenin pathway. Our results stand out together DNMT1 methylation regulates miR-152-3p to slow the progression of cardiac fibrosis by inhibiting the Wnt1/ß-catenin pathway.

DNMT1 Methylation of LncRNA GAS5 Leads to Cardiac Fibroblast Pyroptosis via Affecting NLRP3 Axis.

Cell death and inflammation play critical roles in cardiac fibrosis. During the fibrosis process, inflammation and tissue injury were triggered; however, the mechanisms initiating cardiac fibrosis and driving fibroblast pyroptosis remained largely unknown. In this study, we identified long non-coding RNA (LncRNA)-GAS5 as the key onset of cardiac fibroblast pyroptosis and cardiac fibrosis. Here, we detected ISO-induced cardiac fibrosis models and cardiac fibroblast pyroptosis model by stimulating with LPS. We found that the expression of pyroptosis-related proteins such as caspase 1, NLRP3, and DNMT1 was increased in cardiac fibrosis tissue, while the expression of GAS5 was decreased. The overexpressing of LncRNA GAS5 was shown to increase and inhibit cardiac fibroblast pyroptosis, as well as attenuate caspase 1 and NLRP3 expression in cardiac fibroblast. However, the silencing of GAS5 was also observed; it shows the opposite situation. Furthermore, further studies revealed that treatment of DNMT inhibitor, 5-aza-2-deoxycytidine, or downregulation of DNMT1 led to increased GAS5 expression by reversion of promoter hypermethylation in cardiac fibroblast. Importantly, we have demonstrated that DNMT1 methylation of LncRNA GAS5 leads to cardiac fibroblast pyroptosis via affecting NLRP3 axis. Our findings indicate a new regulatory mechanism for cardiac fibroblast pyroptosis under LPS stress, providing a novel therapeutic target for cardiac fibrosis. Graphical Abstract.

Repair of Hemitruncus With Irreversible Pulmonary Hypertension.

Anomalous origin of the pulmonary artery from the ascending aorta can lead to congestive heart failure in infancy, and with advancing age many patients will experience severe pulmonary hypertension. Surgical intervention has high mortality and morbidity risks if this happens. Strategies to manage these patients seem only limited to heart-lung transplantation or lung transplantation. Here, we successfully performed surgical intervention in an adult patient who had anomalous origin of the right pulmonary artery from the ascending aorta with high pressures in the ascending aorta and normally originating pulmonary artery.

Epigenetic aberrations of miR-369-5p and DNMT3A control Patched1 signal pathway in cardiac fibrosis.

Modulation of epigenetic marks has promised efficacy for treating fibrosis. Cardiac fibroblast is the primary source of activated myofibroblasts that produce extracellular matrix (ECM) in cardiac fibrosis, but the mechanisms underlying this process are incompletely understood. Here we show that microRNA-369-5p (miR-369-5p) through DNMT3A hypermethylation and suppression of the Patched1 pathway leads to fibroblast proliferation in cardiac fibrosis. Forty adult male Sprague-Dawley (SD) rats were randomly divided into two groups (sham and AAC group), cardiac fibrosis was produced by abdominal aortic constriction, and the operation of abdominal aortic constriction was carried out according to the method described. Cardiac fibroblasts (CFs) were harvested from SD neonate rats and cultured. Importantly, miR-369-5p bind directly to DNMT3A with high affinity. MiR-369-5p leads to inhibition of DNMT3A enzyme activity. Exogenous miR-369-5p in cells induces aberrant DNA methylation of the Patched1, resulting in hypermethylation of low to moderately methylated regions. Moreover, Overexpression of miR-369-5p in cardiac fibroblast cells inhibits proliferation. We identify DNMT3A as miR-369-5p target genes and demonstrate that inhibition of miR-369-5p expression augments cell proliferation by activating DNMT3A and suppression of the Patched1 pathway. Together, our results highlight miR-369-5p mediated DNMT3A epigenetic silencing of Patched1 as a mechanism of fibroblast proliferation in cardiac fibrosis.

DNMT3A controls miR-200b in cardiac fibroblast autophagy and cardiac fibrosis.

AIM AND OBJECTIVE: Regulation of microRNA gene expression by DNA methylation may represent a key mechanism to drive cardiac fibrosis progression. Cardiac fibroblast autophagy is the primary source of cardiac fibrosis, but the mechanisms underlying this process are incompletely understood. Here we found that DNMT3A suppression of the microRNA-200b (miR-200b) through pathway leads to cardiac fibroblast autophagy in cardiac fibrosis. METHODS: To understand the impact of DNMT3A on miR-200b at cardiac fibrosis, the rat cardiac fibrosis model was established via the abdominal aortic coarctation. Cardiac fibroblasts (CFs) were harvested from SD neonate rats and cultured. The expression of DNMT3A, miR-200b, collagen I was measured by western blotting, immunohistochemistry and qRT-PCR. Gain- or loss-of-function approaches were used to manipulate DNMT3A and miR-200b. RESULTS: DNMT3A level was upregulated and negatively correlated with miR-200b expression in fibrosis tissues and cardiac fibroblast. We found that autophagy was activated by miR-200b inhibitor and inactivated by miR-200b mimic in the rat cardiac fibroblast. Knockdown of DNMT3A notably increased the expression of miR-200b. CONCLUSIONS: Taken together, these findings indicate that DNMT3A regulation of miR-200b controls cardiac fibroblast autophagy during cardiac fibrosis and provide a basis for the development of therapies for cardiac fibrosis.

Surgical repair of an aortico-left ventricular tunnel with acute infective endocarditis.

Aortic-left ventricular tunnel is a rare congenital cardiac anomaly, which always arises from the right coronary sinus and enters the left ventricle, occasionally the right ventricle and right atrium. However, aortic and left ventricular tunnel associated with infective endocarditis is rarely seen in literatures. Here, we present a case of aortic and left ventricular tunnel associated with infective endocarditis in a 47-year-old man.

DNMT3A silencing RASSF1A promotes cardiac fibrosis through upregulation of ERK1/2.

Cardiac fibrosis contributes to the pathogenesis of atrial fibrillation (AF). The molecular mechanisms underlying the cardiac fibrosis remain unclear. However, Ras association domain family 1 isoform A (RASSF1A) is a regulatory tumor suppressor, which is important for pathogenesis of cardiac fibrosis and fibroblasts activation. Moreover, DNA methylation plays a central role in the maintenance of cardiac fibrosis. DNA methyltransferases 3A (DNMT3A) is a critical participant in the epigenetic silencing of regulatory genes. Here, we report that the downregulation of RASSF1A in cardiac fibrosis is associated with DNMT3A. Treatment of cardiac fibroblasts with DNMT3A inhibitor 5-AzadC blocked proliferation. 5-AzadC also prevented the loss of RASSF1A expression that occurs during activated cardiac fibroblasts. To determine the underlying molecular mechanisms, we hypothesized that cardiac fibrosis is controlled by DNMT3A. We demonstrated that downregulation of RASSF1A is associated with cardiac fibrosis and fibroblasts activation. Knockdown of DNMT3A elevated RASSF1A expression in activated cardiac fibroblasts. Moreover, we investigated the effect of RASSF1A on the Ras/ERK pathway. Upregulation of p-ERK1/2 was detected in activated cardiac fibroblasts with decreased RASSF1A expression. Our results have shown that DNMT3A likely plays an essential role in RASSF1A mediated upregulation of ERK1/2 in rat cardiac fibrosis. DNMT3A and RASSF1A may serve as a new mechanism for cardiac fibrosis.

Role of microRNAs in atrial fibrillation: new insights and perspectives.

MicroRNAs (miRNAs) are small non-coding RNA molecules that negatively regulate gene expression of their targets at the post-transcriptional levels. They typically affect the mRNA stability or translation finally leading to the repression of target gene expression. Notably, it is thought that miRNAs are crucial for regulating gene expression during heart diseases, such as atrial fibrillation (AF). Numerous studies identify specific miRNA expression profiles associated to different histological features of AF, both in animal models and in patients. Therefore, we review the latest experimental approaches from the perspective of understanding miRNA gene expression regulatory networks in AF. In addition, miRNAs have also emerged as possible therapeutic targets for the treatment of AF. In this review, we discuss the experimental evidence about miRNAs both as potential non-invasive early diagnostic markers and as novel therapeutic targets in AF.

Pulmonary lobectomy on delayed inhaled foreign body in adult: a case report.

We present the case of a 51 years old female who experienced foreign body aspiration 3 years before. The foreign body, which should be removed by bronchoscopy before, was lodged at the bifurcation of the right inferior bronchus and could only be removed via right lower lobectomy. The patient experienced a swift recovery and was well at follow-up 8 months later.

Evolution of tricuspid regurgitation after mitral valve surgery for patients with moderate-or-less functional tricuspid regurgitation.

OBJECTIVES: The purpose of this study was to evaluate the impact of moderate-or-less functional tricuspid regurgitation (TR) treatment on the clinical outcome of patients with mitral valve (MV) surgery. METHODS: From October 2001 to January 2005, 167 patients in our hospital with MV surgery and without organic tricuspid valve (TV) disease or pulmonary hypertension (PH) showed moderate-or-less functional TR preoperatively, and 41.9% of these patients were treated with TR (group T), compared with 58.1% untreated with TR (group no-T). According to tricuspid annulus dimension (TAD)/body surface area (BSA), these 167 patients were further divided into another 2 groups (A and B): group A (70 patients) represented TAD/BSA ≤ 21 mm/m2 with 32 patients from group T and 38 from group no-T, and group B (97 patients) represented TAD/BSA > 21 mm/m2 with 38 patients from group T and 59 patients from group no-T. There was no statistical difference in preoperative and operative variables between the 2 groups. Meanwhile, among the 167 patients with MV surgery, 157 patients were replaced with MV and 10 patients were repaired with MV, and De Vega technique was constantly used for TR treatment. All the results were estimated by multivariate analysis. RESULTS: The median follow-up time was 63 months (25th and 75th percentiles are 53 and 94 months, respectively); 30-day mortality was 3% (1.4% in group T versus 4.1% in group no-T; P = .31). Adjusted 5-year survival was 70.7% (66.6%-80.4%) with 85.3% (83.0%-93.4%) in group T and 64.7% (33.7%-58.3%) in group no-T, P = .001. Among the 70 patients with TAD/BSA ≤ 21 mm/m2, patients who received treatment of moderate-or-less TR and those who did not showed similar secondary TR grade at postoperative period (0.5 ± 0.6 in group T versus 0.9 ± 0.9 in group no-T; P = .2) and follow-up (1.3 ± 1.1 in group T versus 1.8 ± 1.1 in group no-T; P = .06). In subgroup B (TAD/BSA > 21 mm/m2), patients who received tricuspid valvoplasty manifested more significantly improved outcome than patients without functional TR at postoperative period (0.8 ± 0.8 in group T versus 1.6 ± 1.3 in group no-T; P = .03) and follow-up (2.0 ± 1.2 in group T versus 3.0 ± 1.1 in group no-T; P = .005). The multivariate analysis identified TAD/BSA > 21 mm/m2 and preoperative atrial fibrillation (AF) as the risk factors for lower survival at follow-up period. CONCLUSIONS: Patients with MV surgery have better midterm outcome when they receive either more aggressive and effective surgical treatment for functional TR or moderate-or-less TR preoperatively. Indexed TAD (TAD/BSA > 21 mm/m2) is a more reliable surgical guideline for the treatment of TR. Preoperative tricuspid annulus dilation and AF might be predictors of late lower survival.