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The response of cardiac fibroblast proliferation to detrimental stimuli is one of the main pathological factors causing heart remodeling. Reactive oxygen species (ROS) mediate the proliferation of cardiac fibroblasts. However, the exact molecular mechanism remains unclear. In vivo, we examined the oxidative modification of miRNAs with miRNA immunoprecipitation with O8G in animal models of cardiac fibrosis induced by Ang II injection or ischemia‒reperfusion injury. Furthermore, in vitro, we constructed oxidation-modified miR-30c and investigated its effects on the proliferation of cardiac fibroblasts. Additionally, luciferase reporter assays were used to identify the target of oxidized miR-30c. We found that miR-30c oxidation was modified by Ang II and PDGF treatment and mediated by excess ROS. We demonstrated that oxidative modification of G to O8G occurred at positions 4 and 5 of the 5′ end of miR-30c (4,5-oxo-miR-30c), and this modification promoted cardiac fibroblast proliferation. Furthermore, CDKN2C is a negative regulator of cardiac fibroblast proliferation. 4,5-oxo-miR-30c misrecognizes CDKN2C mRNA, resulting in a reduction in protein expression. Oxidized miR-30c promotes cardiac fibroblast proliferation by mismatch mRNA of CDKN2C. [ABSTRACT FROM AUTHOR]

Objective: Sodium glucose cotransporter 2 (SGLT2) inhibitors significantly improve cardiovascular outcomes in diabetic patients; however, the mechanism is unclear. We hypothesized that dapagliflozin improves cardiac outcomes via beneficial effects on systemic and cardiac inflammation and cardiac fibrosis. Research and design methods: This randomized placebo-controlled clinical trial enrolled 62 adult patients (mean age 62, 17% female) with type 2 diabetes (T2D) without known heart failure. Subjects were randomized to 12 months of daily 10 mg dapagliflozin or placebo. For all patients, blood/plasma samples and cardiac magnetic resonance imaging (CMRI) were obtained at time of randomization and at the end of 12 months. Systemic inflammation was assessed by plasma IL-1B, TNFα, IL-6 and ketone levels and PBMC mitochondrial respiration, an emerging marker of sterile inflammation. Global myocardial strain was assessed by feature tracking; cardiac fibrosis was assessed by T1 mapping to calculate extracellular volume fraction (ECV); and cardiac tissue inflammation was assessed by T2 mapping. Results: Between the baseline and 12-month time point, plasma IL-1B was reduced (− 1.8 pg/mL, P = 0.003) while ketones were increased (0.26 mM, P = 0.0001) in patients randomized to dapagliflozin. PBMC maximal oxygen consumption rate (OCR) decreased over the 12-month period in the placebo group but did not change in patients receiving dapagliflozin (− 158.9 pmole/min/106 cells, P = 0.0497 vs. − 5.2 pmole/min/106 cells, P = 0.41), a finding consistent with an anti-inflammatory effect of SGLT2i. Global myocardial strain, ECV and T2 relaxation time did not change in both study groups. Clinical Trial.gov Registration: NCT03782259. [ABSTRACT FROM AUTHOR]

Small nucleolar RNAs (snoRNAs) have extremely versatile functions. They regulate cardiac-relevant signaling pathways, oxidative and metabolic cellular stress, gene expression, and intercellular communication. Global downregulation of snoRNA expression was uncovered in patients with congenital heart disease and resembles the expression profiles of developing hearts. A broad snoRNA-tRNA-tRNA fragments (tRF) network regulates cellular transcriptome, translatome, and cardiovascular biology. Cardioprotective effects of cortical bone stem cell-derived exosomes on fibroblast activation are largely mediated by snoRNAs. An association between levels of circulating snoRNAs and myocardial infarction and heart failure has been found, indicating the potential of these snoRNAs as biomarkers. Small nucleolar RNAs (snoRNAs) are emerging as important regulators of cardiovascular (patho)biology. Several roles of snoRNAs have recently been identified in heart development and congenital heart diseases, as well as their dynamic regulation in hypertrophic and dilated cardiomyopathies, coronary heart disease (CHD), myocardial infarction (MI), cardiac fibrosis, and heart failure. Furthermore, reports of changes in vesicular snoRNA expression and altered levels of circulating snoRNAs in response to cardiac stress suggest that snoRNAs also function in cardiac signaling and intercellular communication. In this review, we summarize and discuss key findings and outline the clinical potential of snoRNAs considering current challenges and gaps in the field of cardiovascular diseases (CVDs). [ABSTRACT FROM AUTHOR]

Myocardial infarction is one of the leading causes of mortality globally. Currently, the pleiotropic inflammatory cytokine interleukin-6 (IL-6) is considered to be intimately related to the severity of myocardial injury during myocardial infarction. Interventions targeting IL-6 are a promising therapeutic option for myocardial infarction, but the underlying molecular mechanisms are not well understood. Here, we report the novel role of IL-6 in regulating adverse cardiac remodeling mediated by fibroblasts in a mouse model of myocardial infarction. It was found that the elevated expression of IL-6 in myocardium and cardiac fibroblasts was observed after myocardial infarction. Further, fibroblast-specific knockdown of Il6 significantly attenuated cardiac fibrosis and adverse cardiac remodeling and preserved cardiac function induced by myocardial infarction. Mechanistically, the role of Il6 contributing to cardiac fibrosis depends on signal transduction and activation of transcription (STAT)3 signaling activation. Additionally, Stat3 binds to the Il11 promoter region and contributes to the increased expression of Il11, which exacerbates cardiac fibrosis. In conclusion, these results suggest a novel role for IL-6 derived from fibroblasts in mediating Stat3 activation and substantially augmented Il11 expression in promoting cardiac fibrosis, highlighting its potential as a therapeutic target for cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Excessive extracellular matrix (ECM) deposition is a defining feature of cardiac fibrosis. Most notably, it is characterized by a significant change in the concentration and volume fraction of collagen I, a disproportionate deposition of collagen subtypes, and a disturbed ECM network arrangement, which directly affect the systolic and diastolic functions of the heart. Immune cells that reside within or infiltrate the myocardium, including macrophages, play important roles in fibroblast activation and consequent ECM remodeling. Through both direct and indirect connections to fibroblasts, monocyte-derived macrophages and resident cardiac macrophages play complex, bidirectional, regulatory roles in cardiac fibrosis. In this review, we discuss emerging interactions between fibroblasts and macrophages in physiology and pathologic conditions, providing insights for future research aimed at targeting macrophages to combat cardiac fibrosis. [ABSTRACT FROM AUTHOR]

The leading cause of death among patients with metabolic dysfunction‐associated steatotic liver disease (MASLD) is cardiovascular disease. A significant percentage of MASLD patients develop heart failure driven by functional and structural alterations in the heart. Previously, we observed cardiac dysfunction in hepatocyte‐specific peroxisome proliferator‐activated receptor alpha knockout (PparaHepKO), a mouse model that exhibits hepatic steatosis independent of obesity and insulin resistance. The goal of the present study was to determine mechanisms that underlie hepatic steatosis‐induced cardiac dysfunction in PparaHepKO mice. Experiments were performed in 30‐week‐old PparaHepKO and littermate control mice fed regular chow. We observed decreased cardiomyocyte contractility (0.17 ± 0.02 vs. 0.24 ± 0.02 μm, p < 0.05), increased cardiac triglyceride content (0.96 ± 0.13 vs. 0.68 ± 0.06 mM, p < 0.05), collagen type 1 (4.65 ± 0.25 vs. 0.31 ± 0.01 AU, p < 0.001), and collagen type 3 deposition (1.32 ± 0.46 vs. 0.05 ± 0.03 AU, p < 0.05). These changes were associated with increased apoptosis as indicated by terminal deoxynucleotidyl transferase dUTP nick end labeling staining (30.9 ± 4.7 vs. 13.1 ± 0.8%, p < 0.006) and western blots showing increased cleaved caspase‐3 (0.27 ± 0.006 vs. 0.08 ± 0.01 AU, p < 0.003) and pro‐caspase‐3 (5.4 ± 1.5 vs. 0.5 ± 0.3 AU, p < 0.02), B‐cell lymphoma protein 2‐associated X (0.68 ± 0.07 vs. 0.04 ± 0.04 AU, p < 0.001), and reduced B‐cell lymphoma protein 2 (0.29 ± 0.01 vs. 1.47 ± 0.54 AU, p < 0.05). We further observed elevated circulating natriuretic peptides and exercise intolerance in PparaHepKO mice when compared to controls. Our data demonstrated that lipotoxicity, and fibrosis underlie cardiac dysfunction in MASLD. [ABSTRACT FROM AUTHOR]

Background: Diabetic cardiomyopathy (DCM) is a serious health-threatening complication of diabetes mellitus characterized by myocardial fibrosis and abnormal cardiac function. Human umbilical cord mesenchymal stromal cells (hUC-MSCs) are a potential therapeutic tool for DCM and myocardial fibrosis via mechanisms such as the regulation of microRNA (miRNA) expression and inflammation. It remains unclear, however, whether hUC-MSC therapy has beneficial effects on cardiac function following different durations of diabetes and which mechanistic aspects of DCM are modulated by hUC-MSC administration at different stages of its development. This study aimed to investigate the therapeutic effects of intravenous administration of hUC-MSCs on DCM following different durations of hyperglycemia in an experimental male model of diabetes and to determine the effects on expression of candidate miRNAs, target mRNA and inflammatory mediators. Methods: A male mouse model of diabetes was induced by multiple low-dose streptozotocin injections. The effects on severity of DCM of intravenous injections of hUC-MSCs and saline two weeks previously were compared at 10 and 18 weeks after diabetes induction. At both time-points, biochemical assays, echocardiography, histopathology, polymerase chain reaction (PCR), immunohistochemistry and enzyme-linked immunosorbent assays (ELISA) were used to analyze blood glucose, body weight, cardiac structure and function, degree of myocardial fibrosis and expression of fibrosis-related mRNA, miRNA and inflammatory mediators. Results: Saline-treated diabetic male mice had impaired cardiac function and increased cardiac fibrosis after 10 and 18 weeks of diabetes. At both time-points, cardiac dysfunction and fibrosis were improved in hUC-MSC-treated mice. Pro-fibrotic indicators (α-SMA, collagen I, collagen III, Smad3, Smad4) were reduced and anti-fibrotic mediators (FGF-1, miRNA-133a) were increased in hearts of diabetic animals receiving hUC-MSCs compared to saline. Increased blood levels of pro-inflammatory cytokines (IL-6, TNF, IL-1β) and increased cardiac expression of IL-6 were also observed in saline-treated mice and were reduced by hUC-MSCs at both time-points, but to a lesser degree at 18 weeks. Conclusion: Intravenous injection of hUC-MSCs ameliorated key functional and structural features of DCM in male mice with diabetes of shorter and longer duration. Mechanistically, these effects were associated with restoration of intra-myocardial expression of miRNA-133a and its target mRNA COL1AI as well as suppression of systemic and localized inflammatory mediators. [ABSTRACT FROM AUTHOR]

Background and Purpose Experimental Approach Key Results Conclusions and Implications Excessive fibrogenesis is associated with adverse cardiac remodelling and heart failure. The myofibroblast, primarily derived from resident fibroblast, is the effector cell type in cardiac fibrosis. Megakaryocytic leukaemia 1 (MKL1) is considered the master regulator of fibroblast–myofibroblast transition (FMyT). The underlying transcriptional mechanism is not completely understood. Our goal was to identify novel transcriptional targets of MKL1 that might regulate FMyT and contribute to cardiac fibrosis.RNA sequencing (RNA‐seq) performed in primary cardiac fibroblasts identified insulin‐like growth factor binding protein 5 (IGFBP5) as one of the genes most significantly up‐regulated by constitutively active (CA) MKL1 over‐expression. IGFBP5 expression was detected in heart failure tissues using RT‐qPCR and western blots.Once activated, IGFBP5 translocated to the nucleus to elicit a pro‐FMyT transcriptional programme. Consistently, IGFBP5 knockdown blocked FMyT in vitro and dampened cardiac fibrosis in mice. Of interest, IGFBP5 interacted with nuclear factor of activated T‐cell 4 (NFAT4) to stimulate the transcription of microfibril‐associated protein 5 (MFAP5). MFAP5 contributed to FMyT and cardiac fibrosis by enabling sterol response element binding protein 2 (SREBP2)‐dependent cholesterol synthesis.Our data unveil a previously unrecognized transcriptional cascade, initiated by IGFBP5, that promotes FMyT and cardiac fibrosis. Screening for small‐molecule compounds that target this axis could yield potential therapeutics against adverse cardiac remodelling. [ABSTRACT FROM AUTHOR]

Background: Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro‐inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear. Methods: Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3‐AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme‐linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT‐PCR) were performed to quantify inflammatory factors (IL‐1β, IL‐6, TNF‐α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase‐myocardial band (CK‐MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α‐SMA, TGF‐β1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining. Results: In vivo, CVB3‐AMG487 reduced cardiac injury, α‐SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL‐1β, IL‐6, and TNF‐α). In vitro, CXCL4/CXCR3B axis activation TGF‐β1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation. Conclusion: CXCL4 acts as a profibrotic factor in TGF‐β1/Smad2/3 pathway‐induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC. [ABSTRACT FROM AUTHOR]

Altered cardiac innate immunity is highly associated with the progression of cardiac disease states and heart failure. S100A8/A9 is an important component of damage-associated molecular patterns (DAMPs) that is critically involved in the pathogenesis of heart failure, thus considered a promising target for pharmacological intervention. In the current study, initially, we validated the role of S100A8/A9 in contributing to cardiac injury and heart failure via the overactivation of the β-adrenergic pathway and tested the potential use of paquinimod as a pharmacological intervention of S100A8/A9 activation in preventing cardiac dysfunction, collagen deposition, inflammation, and immune cell infiltration in β-adrenergic overactivation–mediated heart failure. This finding was further confirmed by the cardiomyocyte-specific silencing of S100A9 via the use of the adeno-associated virus (AAV) 9-mediated short hairpin RNA (shRNA) gene silencing system. Most importantly, in the assessment of the underlying cellular mechanism by which activated S100A8/A9 cause aggravated progression of cardiac fibrosis and heart failure, we discovered that the activated S100A8/A9 can promote fibroblast-macrophage interaction, independent of inflammation, which is likely a key mechanism leading to the enhanced collagen production. Our results revealed that targeting S100A9 provides dual beneficial effects, which is not only a strategy to counteract cardiac inflammation but also preclude cardiac fibroblast-macrophage interactions. The findings of this study also indicate that targeting S100A9 could be a promising strategy for addressing cardiac fibrosis, potentially leading to future drug development. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are a leading cause of morbidity and mortality world-wide. While many factors like smoking, hypertension, diabetes, dyslipidaemia, a sedentary lifestyle, and genetic factors can predispose to cardiovascular diseases, the natural process of aging is by itself a major determinant of the risk. Cardiac aging is marked by a conglomerate of cellular and molecular changes, exacerbated by age-driven decline in cardiac regeneration capacity. Although the phenotypes of cardiac aging are well characterised, the underlying molecular mechanisms are far less explored. Recent advances unequivocally link cardiovascular aging to the dysregulation of critical signalling pathways in cardiac fibroblasts, which compromises the critical role of these cells in maintaining the structural and functional integrity of the myocardium. Clearly, the identification of cardiac fibroblast-specific factors and mechanisms that regulate cardiac fibroblast function in the senescent myocardium is of immense importance. In this regard, recent studies show that Discoidin domain receptor 2 (DDR2), a collagen-activated receptor tyrosine kinase predominantly located in cardiac fibroblasts, has an obligate role in cardiac fibroblast function and cardiovascular fibrosis. Incisive studies on the molecular basis of cardiovascular aging and dysregulated fibroblast function in the senescent heart would pave the way for effective strategies to mitigate cardiovascular diseases in a rapidly growing elderly population. [ABSTRACT FROM AUTHOR]

Objective(s): Slit guidance ligand 3 (SLIT3) has been identified as a potential therapeutic regulator against fibroblast activity and fibrillary collagen production in an autocrine manner. However, this research aims to investigate the potential role of SLIT3 in cardiac fibrosis and fibroblast differentiation and its underlying mechanism. Materials and Methods: C57BL/6 mice (male, 8-10 weeks, n=47) were subcutaneously infused with Ang II (2.0 mg/kg/day) for 4 weeks. One to two-day-old Sprague-Dawley (SD) rats were anesthetized by intraperitoneal injection of 1% pentobarbital sodium (60 mg/kg) and ketamine (50 mg/kg) and the cardiac fibroblast was isolated aseptically. The mRNA and protein expression were analyzed using RT-qPCR and Western blotting. Results: The SLIT3 expression level was increased in Ang II-induced mice models and cardiac fibroblasts. SLIT3 significantly increased migrated cells and α-smooth muscle actin (α-SMA) expression in cardiac fibroblasts. Ang II-induced increases in mRNA expression of collagen I (COL1A1), and collagen III (COL3A1) was attenuated by SLIT3 inhibition. SLIT3 knockdown attenuated the Ang II-induced increase in mRNA expression of ACTA2 (α-SMA), Fibronectin, and CTGF. SLIT3 suppression potentially reduced DHE expression and decreased malondialdehyde (MDA) content, and the superoxide dismutase (SOD) and catalase (CAT) levels were significantly increased in cardiac fibroblasts. Additionally, SLIT3 inhibition markedly decreased RhoA and ROCK1 protein expression, whereas ROCK inhibitor Y-27632 (10 μM) markedly attenuated the migration of cardiac fibroblasts stimulated by Ang II and SLIT3. Conclusion: The results speculate that SLIT3 could significantly regulate cardiac fibrosis and fibroblast differentiation via the RhoA/ROCK1 signaling pathway. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) stands as the foremost cause of patient mortality, and the lack of early diagnosis and defined treatment targets significantly contributes to the suboptimal prevention and management of CVD. Myocardial fibrosis (MF) is not only a complex pathogenic process with no effective treatment currently available but also exerts detrimental effects on the progression of various cardiovascular diseases, thereby escalating their mortality rates. Exosomes are nanoscale biocommunication vehicles that facilitate intercellular communication by transporting bioactive substances, such as nucleic acids and proteins, from specific cell types. Numerous studies have firmly established that microRNAs (miRNAs), as non-coding RNAs, wield post-transcriptional regulatory mechanisms and exhibit close associations with various CVDs, including coronary heart disease (CHD), atrial fibrillation (AF), and heart failure (HF). MiRNAs hold significant promise in the diagnosis and treatment of cardiovascular diseases. In this review, we provide a concise introduction to the biological attributes of exosomes and exosomal miRNAs. We also explore the roles and mechanisms of distinct cell-derived exosomal miRNAs in the context of myocardial fibrosis. These findings underscore the pivotal role of exosomes in the diagnosis and treatment of cardiac fibrosis and emphasize their potential as biotherapies and drug delivery vectors for cardiac fibrosis treatment. [ABSTRACT FROM AUTHOR]

Objective： To explore the effect and mechanism of neuropeptide Y (NPY)/Y1 receptor signaling in myocardial injury. Methods： The C57BL/6J mice model of cardiac injury was established by subcutaneous injection with isoproterenol (ISO), which was subsequently treated with the specific NPY/Y1 receptor antagonist BIBO3304 by intraperitoneal injection. C57BL/6J mice were randomly divided into 4 groups： control group (Saline), ISO group[20 mg/ (kg · d)ISO], BIBO3304 + ISO group[0.1 mg/ (kg · d) BIBO3304+20 mg/ (kg·d)ISO], and BIBO3304 group[0.1 mg/ (kg·d)BIBO3304]. All the drug was administered continuously for 14 days. The expression of NPY mRNA and protein in the heart of mice were detected by qPCR and Western blot, respectively. The change of myocardial fiber structure and myocardial fibrosis were observed by HE and Masson staining. Levels of cardiac hypertrophy related gene, atrial natriuretic peptide (ANP)and β-myosin heavy chain (β-MHC)mRNA in the heart of mice were also estimated by qPCR.[Leu31, Pro34]-NPY, a specific Y1 receptor agonist, was used to directly treat H9C2 cells in vitro. The mRNA levels of ANP and β-MHC in the cardiomyocytes were detected by qPCR, and the cell viability of H9C2 was measured by CCK-8. The expressions of active β-catenin, phospho-glycogen synthesis kinase 3β (p-GSK3β)and total glycogen synthesis kinase 3β (t-GSK3β)in the heart and H9C2 cells were analyzed by Western blot. Nuclear β- catenin accumulation was estimated by immunofluorescence staining. ICG001, a specific β-catenin inhibitor, was used to treat H9C2, and the cardiomyocyte hypertrophy and cell viability induced by[Leu31, Pro34]- NPY were further examined. Results： Compared with the control group, cardiac NPY mRNA and protein expressions were increased significantly in ISO group (P < 0.05), in which it exhibited myocardial fiber arrangement disorder, high degree of myocardial fibrosis and increased expression of cardiac hypertrophy related gene. Compared with the ISO group, the myocardial damage and fibrosis were effectively alleviated in BIBO3304+ISO group, and the expression of cardiac hypertrophy related gene were decreased (P < 0.01). Compared with the control group, [Leu31, Pro34]-NPY increased ANP and β-MHC mRNA levels, and decreased cell viability in H9C2 cardiomyocytes (P < 0.01). Compared with the control group, the protein expressions of active β- catenin and p-GSK3β/t-GSK3β were increased in the heart of mice from ISO group (P < 0.05). Compared with the ISO group, the expressions of active β-catenin and p-GSK3β were decreased in BIBO3304+ISO group (P < 0.05). Compared with the control group, [Leu31, Pro34]-NPY increased expressions of active β-catenin and p-GSK3β, as well as facilitated nuclear β-catenin accumulation in the cardiomyocytes (P < 0.05). Compared with[Leu31, Pro34]-NPY group, BIBO3304 decreased β-catenin expression in the nucleus, and ICG001 effectively alleviated cardiomyocyte hypertrophy and cell viability reduction (P < 0.01). Conclusion：NPY/Y1 receptor mediates cardiomyocyte injury and fibrosis through β-catenin pathway. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is a pathological reparative process that follows myocardial infarctionand is associated with compromised cardiac systolic and reduced cardiac compliance. The Wnt signaling pathway is closely implicated in organ fibrosis, and Notum, a highly conserved secreted inhibitor, modulates Wnt signaling. The objective of this study was to explore the role and mechanism of Notum in cardiac fibrosis. A mouse model of cardiac remodeling was established through left coronary artery ligation surgery, with the addition of Notum injection following myocardial infarction surgery. The protective effect of Notum on myocardial infarction was assessed by evaluating cardiac function, including survival rate, echocardiographic assessment, and cardiac contraction analyses. Inflammatory cell necrosis and infiltration were confirmed through H&E and Masson staining. The expression of fibrosis-related genes and β-catenin pathway markers was detected using Western blot quantificational RT-PCR (qRT-PCR). Additionally, EdU, wound healing, and immunofluorescence staining analyses were performed to detect the effect of Notum's in transforming growth factor beta-1 (TGF-β1) induced myofibroblast transformation. The administration of Notum treatment resulted in enhanced survival rates, improved cardiac function, and decreased necrosis and infiltration of inflammatory cells in mice subjected to left coronary artery ligation. Furthermore, Notum effectively impeded the senescence of cardiac fibroblasts and hindered their pathological transformation into cardiac fibroblasts. Additionally, it significantly reduced collagen production and attenuated the activation of the Wnt/β-catenin pathway. Our preliminary investigations successfully demonstrated the therapeutic potential of Notum in both fibroblasts in vitro and in a mouse model of myocardial infarction-induced cardiac fibrosis in vivo. Notum inhibition of the Wnt/β-catenin signaling pathway and cardiac fibroblast senescence ultimately hampers the onset of cardiac fibrosis. Our findings suggest that Notum could represent a new therapeutic strategy for the treatment of cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Cardiovascular and metabolic diseases such as hypertension, type 2 diabetes, and obesity develop long-term fibrotic processes in the heart, promoting pathological cardiac remodeling, including after myocardial infarction, reparative fibrotic processes also occur. These processes are regulated by many intracellular signaling pathways that have not yet been completely elucidated, including those associated with microRNA (miRNA) expression. miRNAs are small RNA transcripts (18-25 nucleotides in length) that act as posttranscriptionally regulators of gene expression, inhibiting or degrading one or more target messenger RNAs (mRNAs), and proven to be involved in many biological processes such as cell cycle, differentiation, proliferation, migration, and apoptosis, directly affecting the pathophysiology of several diseases, including cardiac fibrosis. Exercise training can modulate the expression of miRNAs and it is known to be beneficial in various cardiovascular diseases, attenuating cardiac fibrosis processes. However, the signaling pathways modulated by the exercise associated with miRNAs in cardiac fibrosis were not fully understood. Thus, this review aims to analyze the expression of miRNAs that modulate signaling pathways in cardiac fibrosis processes that can be regulated by exercise training. [ABSTRACT FROM AUTHOR]

Radiotherapy-induced cardiac toxicity and consequent diseases still represent potential severe late complications for many cancer survivors who undergo therapeutic thoracic irradiation. We aimed to assess the phenotypic and paracrine features of resident cardiac mesenchymal stromal cells (CMSCs) at early follow-up after the end of thoracic irradiation of the heart as an early sign and/or mechanism of cardiac toxicity anticipating late organ dysfunction. Resident CMSCs were isolated from a rat model of fractionated thoracic irradiation with accurate and clinically relevant heart dosimetry that developed delayed dose-dependent cardiac dysfunction after 1 year. Cells were isolated 6 and 12 weeks after the end of radiotherapy and fully characterized at the transcriptional, paracrine, and functional levels. CMSCs displayed several altered features in a dose- and time-dependent trend, with the most impaired characteristics observed in those exposed in situ to the highest radiation dose with time. In particular, altered features included impaired cell migration and 3D growth and a and significant association of transcriptomic data with GO terms related to altered cytokine and growth factor signaling. Indeed, the altered paracrine profile of CMSCs derived from the group at the highest dose at the 12-week follow-up gave significantly reduced angiogenic support to endothelial cells and polarized macrophages toward a pro-inflammatory profile. Data collected in a clinically relevant rat model of heart irradiation simulating thoracic radiotherapy suggest that early paracrine and transcriptional alterations of the cardiac stroma may represent a dose- and time-dependent biological substrate for the delayed cardiac dysfunction phenotype observed in vivo. [ABSTRACT FROM AUTHOR]

Heart diseases remain the primary cause of human mortality in the world. Although conventional therapeutic opportunities fail to halt or recover cardiac fibrosis, the promising clinical results and therapeutic efficacy of engineered chimeric antigen receptor (CAR) T cell therapy show several advancements. However, the current models of CAR‐T cells need further improvement since the T cells are associated with the triggering of excessive inflammatory cytokines that directly affect cardiac functions. Thus, the current study highlights the critical function of heart immune cells in tissue fibrosis and repair. The study also confirms CAR‐T cell as an emerging therapeutic for treating cardiac fibrosis, explores the current roadblocks to CAR‐T cell therapy, and considers future outlooks for research development. Significance statement: The necessity and importance of chimeric antigen receptor (CAR) T cells and their therapeutic efficiency in treating diseases other than cancer, mainly cardiovascular diseases, have emerged in recent years. However, there is still room for advancement in the current models of CAR‐T cell therapy. This paper highlights the evolution and roadblocks of CAR‐T technology at different levels, from technical concerns to clinical outcomes, in an attempt to improve the therapeutic efficiency of CAR‐T cell therapy in this area. [ABSTRACT FROM AUTHOR]

Developing effective anti-fibrotic therapies for heart diseases holds the potential to address unmet needs in several cardiac conditions, including heart failure with preserved ejection fraction, hypertrophic cardiomyopathy, and cardiotoxicity induced by cancer therapy. The inhibition of the primary fibrotic regulator, transforming growth factor (TGF) β, represents an efficient strategy for mitigating fibrosis in preclinical models. However, translating these findings into clinical benefits faces challenges due to potential adverse effects stemming from TGF-β's physiological actions in inflammation and tissue homeostasis. Various strategies exist for inhibiting TGF-β, each associated with a distinct risk of adverse effects. Targeting TGF-β directly or through its signaling pathway proves efficient in reducing fibrosis. However, direct TGF-β blockade may lead to uncontrolled inflammation, especially following myocardial infarction, while interference with the signaling pathway may compromise structural integrity, resulting in issues like insufficient wound healing or ventricular dilatation. Influencing TGF-β activity through interacting signaling pathways, for instance by inhibitors of the renin–angiotensin–aldosterone-system, is insufficiently potent in reducing fibrosis. Targeting activators of latent TGF-β, including ADAMTS enzymes, thrombospondin, and integrins, emerges as a potentially safer strategy to reduce TGF-β-induced fibrosis but it requires the identification of appropriate targets. Encouragement is drawn from promising agents developed for fibrosis in other organs, fueling hope for similar breakthroughs in treating cardiac fibrosis. Such advances depend on overcoming obstacles for the implementation of anti-fibrotic strategies in patients with heart disease, including fibrosis quantification. In this review, insights garnered from interventional and mechanistic studies, obtained through a non-systemic search spanning preclinical and clinical evidence, are summarized to pinpoint the most promising targets for further exploration and development. [ABSTRACT FROM AUTHOR]

Sphingolipids (SLs) are vital constituents of the plasma membrane of animal cells and concurrently regulate numerous cellular processes. An escalating number of research have evinced that SLs assume a crucial part in the progression of tissue fibrosis, a condition for which no efficacious cure exists as of now. Cardiac fibrosis, and in particular, atrial fibrosis, is a key factor in the emergence of atrial fibrillation (AF). AF has become one of the most widespread cardiac arrhythmias globally, with its incidence continuing to mount, thereby propelling it to the status of a major public health concern. This review expounds on the structure and biosynthesis pathways of several pivotal SLs, the pathophysiological mechanisms of AF, and the function of SLs in cardiac fibrosis. Delving into the influence of sphingolipid levels in the alleviation of cardiac fibrosis offers innovative therapeutic strategies to address cardiac fibrosis and AF. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is a common consequence of different types of cardiac injury. Reprogramming of lipid metabolism has a key role in cardiac fibrosis. Multiple lipid categories have been shown to exert diverse effects in cardiac fibrosis. Several pharmacological interventions targeting lipid metabolism reprogramming and ferroptosis are under investigation for the management of cardiac fibrosis. Cardiac fibrosis is a critical pathophysiological process that occurs with diverse types of cardiac injury. Lipids are the most important bioenergy substrates for maintaining optimal heart performance and act as second messengers to transduce signals within cardiac cells. However, lipid metabolism reprogramming is a double-edged sword in the regulation of cardiomyocyte homeostasis and heart function. Moreover, lipids can exert diverse effects on cardiac fibrosis through different signaling pathways. In this review, we provide a brief overview of aberrant cardiac lipid metabolism and recent progress in pharmacological research targeting lipid metabolism alterations in cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Background: Heart failure due to myocardial infarction (MI) involves fibrosis driven by epicardium‐derived cells (EPDCs) and cardiac fibroblasts, but strategies to inhibit and provide cardio‐protection remains poor. The imprinted gene, non‐canonical NOTCH ligand 1 (Dlk1), has previously been shown to mediate fibrosis in the skin, lung and liver, but very little is known on its effect in the heart. Methods: Herein, human pericardial fluid/plasma and tissue biopsies were assessed for DLK1, whereas the spatiotemporal expression of Dlk1 was determined in mouse hearts. The Dlk1 heart phenotype in normal and MI hearts was assessed in transgenic mice either lacking or overexpressing Dlk1. Finally, in/ex vivo cell studies provided knowledge on the molecular mechanism. Results: Dlk1 was demonstrated in non‐myocytes of the developing human myocardium but exhibited a restricted pericardial expression in adulthood. Soluble DLK1 was twofold higher in pericardial fluid (median 45.7 [34.7 (IQR)) μg/L] from cardiovascular patients (n = 127) than in plasma (median 26.1 μg/L [11.1 (IQR)]. The spatial and temporal expression pattern of Dlk1 was recapitulated in mouse and rat hearts. Similar to humans lacking Dlk1, adult Dlk1−/− mice exhibited a relatively mild developmental, although consistent cardiac phenotype with some abnormalities in heart size, shape, thorax orientation and non‐myocyte number, but were functionally normal. However, after MI, scar size was substantially reduced in Dlk1−/− hearts as compared with Dlk1+/+ littermates. In line, high levels of Dlk1 in transgenic mice Dlk1fl/flxWT1GFPCre and Dlk1fl/flxαMHCCre/+Tam increased scar size following MI. Further mechanistic and cellular insight demonstrated that pericardial Dlk1 mediates cardiac fibrosis through epithelial to mesenchymal transition (EMT) of the EPDC lineage by maintaining Integrin β8 (Itgb8), a major activator of transforming growth factor β and EMT. Conclusions: Our results suggest that pericardial Dlk1 embraces a, so far, unnoticed role in the heart augmenting cardiac fibrosis through EMT. Monitoring DLK1 levels as well as targeting pericardial DLK1 may thus offer new venues for cardio‐protection. [ABSTRACT FROM AUTHOR]

Cardiac fibroblasts are essential for the homeostasis of the extracellular matrix, whose remodeling in many cardiovascular diseases leads to fibrosis. Long noncoding RNAs (lncRNAs) are associated with cardiac pathologies, but their functions in cardiac fibroblasts and contributions to cardiac fibrosis remain unclear. Here, we aimed to identify fibroblast-enriched lncRNAs essential in myocardial infarction (MI)-induced fibrosis and explore the molecular mechanisms responsible for their functions. Global lncRNA profiling was performed in post-MI mouse heart ventricles and transforming growth factor-β (TGF-β)-treated primary cardiac fibroblasts and confirmed in published data sets. We identified the cardiac fibroblast-enriched lncPostn, whose expression is stimulated in cardiac fibrosis induced by MI and the extracellular growth factor TGF-β. The promoter of lncPostn contains a functional TGF-β response element, and lncPostn knockdown suppresses TGF-β-stimulated cardiac fibroblast activation and improves cardiac functions post-MI. LncPostn stabilizes and recruits EP300 to the profibrotic periostin’s promoter, representing a major mechanism for its transcriptional activation. Moreover, both MI and TGF-β enhance lncPostn expression while suppressing the cellular growth gatekeeper p53. TGF-β and p53 knockdown-induced profibrotic gene expression and fibrosis occur mainly through lncPostn and show additive effects. Finally, levels of serum lncPostn are significantly increased in patients’ postacute MI and show a strong correlation with fibrosis markers, revealing a potential biomarker of cardiac fibrosis. Our findings identify the fibroblast-enriched lncPostn as a potent profibrotic factor, providing a transcriptional link between TGF-β and p53 signaling pathways to regulate fibrosis in cardiac fibroblasts. NEW & NOTEWORTHY Cardiac fibroblasts are essential for the homeostasis of the extracellular matrix, whose remodeling in many cardiovascular diseases leads to fibrosis. Long noncoding RNAs are functional and contribute to the biological processes of cardiovascular development and disorders. Our findings identify the fibroblast-enriched lncPostn as a potent profibrotic factor and demonstrate that serum lncPostn level may serve as a potential biomarker of human cardiac fibrosis postacute myocardial infarction. [ABSTRACT FROM AUTHOR]

Introduction: There is still no effective treatment for heart failure with preserved left ventricular ejection fraction (HFpEF), and therapies to improve prognosis are urgently needed. Clinical studies in patients with HFpEF have shown that statins and HMG-CoA reductase inhibitors may reduce their mortality rate. However, the mechanisms underlying the effects of statins on HFpEF remain unknown. In the present study, we examined whether simvastatin administration inhibits the development of cardiac fibrosis in HFpEF model mice. We further examined the contribution of the Smad and mitogen-activated protein (MAP) kinase pathways to the transforming growth factor-β (TGF-β) signaling pathway in the development of HFpEF. Methods: HFpEF animals were prepared by feeding C57BL/6 N mice a high-fat diet and providing water containing N[w]-nitro-l-arginine methyl ester hydrochloride (l-NAME) for 15 weeks. Simvastatin (30 mg/kg/day) or vehicle was administered orally daily during the experimental period. Cardiac function was measured by echocardiography, and cardiac fibrosis was evaluated by Masson's trichrome staining. Changes in the TGF-β signaling proteins in myocardial tissue were examined by Western blotting. Results: A high-fat diet and l-NAME solution load induced cardiac diastolic dysfunction with cardiac fibrosis. Simvastatin treatment markedly attenuated cardiac fibrosis and reduced cardiac diastolic dysfunction. In addition, simvastatin prevented the increase in phosphorylation levels of Smad (Smad2 and Smad3) and MAPK (c-Raf, Erk1/2) pathway proteins downstream of the TGF-β receptor in cardiac tissue. Conclusions: Our present study demonstrated that simvastatin attenuated diastolic dysfunction by reducing cardiac fibrosis in HFpEF hearts. Furthermore, our findings suggest that the mechanisms by which simvastatin attenuates HFpEF development involve, at least in part, inhibition of the TGF-β signaling pathway, which is activated in the HFpEF heart. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is the cause of physical infirmity and thousands of deaths annually. Typically, during heart failure, cardiomyocyte mitochondria falter in terms of energy production and metabolic processing. Additionally, inflammation and the accumulation of non-contractile fibrous tissue contribute to cardiac malfunction. Melatonin, an endogenously produced molecule, experimentally reduces the initiation and progression of atherosclerotic lesions, which are often the basis of coronary artery disease. The current review critically analyzes published data related to the experimental use of melatonin to forestall coronary artery pathologies. Collectively, these studies document melatonin's anti-atherosclerotic actions in reducing LDL oxidation and triglyceride levels, lowering endothelial malfunction, limiting adhesion molecule formation, preventing macrophage polarization to the M1 pro-inflammatory phenotype, changing cellular metabolism, scavenging destructive reactive oxygen species, preventing the proliferation and invasion of arterial smooth muscle cells into the lesioned area, restricting the ingrowth of blood vessels from the vasa vasorum, and solidifying the plaque cap to reduce the chance of its rupture. Diabetic hyperglycemia, which aggravates atherosclerotic plaque formation, is also inhibited by melatonin supplementation in experimental animals. The potential value of non-toxic melatonin as a possible inhibitor of cardiac pathology in humans should be seriously considered by performing clinical trials using this multifunctional molecule. [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

The SLIT family (SLIT1-3) of highly conserved glycoproteins was originally identified as ligands for the Roundabout (ROBO) family of single-pass transmembrane receptors, serving to provide repulsive axon guidance cues in the nervous system. Intriguingly, studies involving SLIT3 mutant mice suggest that SLIT3 might have crucial biological functions outside the neural context. Although these mutant mice display no noticeable neurological abnormalities, they present pronounced connective tissue defects, including congenital central diaphragmatic hernia, membranous ventricular septal defect, and osteopenia. We recently hypothesized that the phenotype observed in SLIT3-deficient mice may be tied to abnormalities in fibrillar collagen-rich connective tissue. Further research by our group indicates that both SLIT3 and its primary receptor, ROBO1, are expressed in fibrillar collagen-producing cells across various nonneural tissues. Global and constitutive SLIT3 deficiency not only reduces the synthesis and content of fibrillar collagen in various organs but also alleviates pressure overload-induced fibrosis in both the left and right ventricles. This review delves into the known phenotypes of SLIT3 mutants and the debated role of SLIT3 in vasculature and bone. Present evidence hints at SLIT3 acting as an autocrine regulator of fibrillar collagen synthesis, suggesting it as a potential antifibrotic treatment. However, the precise pathway and mechanisms through which SLIT3 regulates fibrillar collagen synthesis remain uncertain, presenting an intriguing avenue for future research. [ABSTRACT FROM AUTHOR]

Andrographolide (Andr) is a bioactive Andr diterpenoid extracted from herbaceous Andrographis paniculata (Burm. F.) Wall. ex Nees (Acanthaceae). Andr can relieve cardiac dysfunction in mice by inhibiting the mitogen-activated protein kinases (MAPK) pathway. This study investigates the efficacy and underlying mechanism of Andr on cardiac hypertrophy in mice. Male C57 mice (20–25 g, 6–8 weeks) were divided into four groups (n = 10 mice/group) as sham group (sham operation), transverse aortic constriction (TAC) model group, TAC + Andr 100 mg/kg group and TAC + Andr 200 mg/kg group. Andr groups were given intragastric administration of Andr (100 and 200 mg/kg) once a day for 14 consecutive days. An in vitro hypertrophy model was established by adding 1 μM of Ang II to H9c2 cells for 48 h induction. In TAC-mice, Andr improved echocardiographic indices [reduced LVESD (30.4% or 37.1%) and LVEDD (24.8% or 26.4%), increased EF (22.9% or 42.6%) and FS (25.4% or 52.2%)], reduced BNP (11.5% or 23.6%) and Ang II levels (10.3% or 32.8%), attenuates cardiac fibrosis and reduces cardiac cell apoptosis in TAC mice. In vitro, Andr attenuated cardiomyocyte hypertrophy and decreased the protein expression of GRP78 (67.8%), GRP94 (47.6%), p-PERK (44.9%) and CHOP (66.8%) in Ang-II-induced H9c2 cells and reversed after endoplasmic reticulum (ER) stress agonist Tunicamycin (TN) treatment. Andr was found to be an anti-hypertrophic regulator, which could attenuate cardiac hypertrophy by suppressing ER stress. It may be a new therapeutic drug for cardiac hypertrophy. [ABSTRACT FROM AUTHOR]

We investigated the effects of pravastatin (PRAVA) on isoprenaline (ISP) induced cardiac fibrosis using four groups of mice: untreated control, PRAVA, ISP, ISP + PRAVA groups. ISP, 20 mg/kg, was administered subcutaneously daily for 14 days. PRAVA, 20 mg/kg, was administered orally daily for 14 days. Mice were sacrificed on day15 and heart and blood samples were collected to investigate cardiac injury markers. The mean body weight for the ISP group on day 15 was decreased significantly compared to day 0; PRAVA increased the mean body weight slightly on day 15 of treatment compared to day 0. The heart:body weight ratio was increased in the ISP group compared to the control group, but the ratio was returned to near control ratio in the PRAVA + ISP group. The serum creatine kinase-myocardial band (CK-MB) level was reduced significantly in the PRAVA + ISP group compared to the ISP group. Serum triglyceride level was decreased significantly in ISP + PRAVA group compared to the ISP group. PRAVA administration significantly reduced tissue collagen I and III levels in the ISP + PRAVA group compared to the ISP group. Lipid oxidation was decreased and reduced glutathione activity was increased in the PRAVA + ISP group compared to the ISP group. IL-6, α-SMA, CTGF, TGF-β and SMAD-3 gene expressions were decreased in the PRAVA + ISP group compared to the ISP group. We found fewer inflammatory cells and less fibrosis in heart tissue in the PRAVA + ISP group compared to the ISP group. PRAVA decreased ISP induced cardiac fibrosis by reducing oxidative stress, collagen deposition and inflammation, as well as by decreasing expression of TGF-β, SMAD-3 and CTGF genes. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis contributes to adverse ventricular remodeling and is associated with loss of miR-29b. Overexpression of miR-29b via plasmid or intravenous injection of microRNA mimic has blunted fibrosis, but these are inefficient and non-targeted delivery strategies. In this study, we tested the hypothesis that delivery of microRNA-29b (miR-29b) using ultrasound-targeted microbubble cavitation (UTMC) of miR-29b-loaded microbubbles would attenuate cardiac fibrosis and preserve left ventricular (LV) function. Lipid microbubbles were loaded with miR-29b mimic (miR-29b-MB) or negative control (NC) mimic (NC-MB), placed with cardiac fibroblasts (CFs) and treated with pulsed ultrasound. Cells were harvested to measure downstream fibrotic mediators. Mice received angiotensin II (ANG II) infusion causing afterload increase and direct ANG II-induced cardiac fibrosis. UTMC of miRNA-loaded microbubbles was administered to the heart at days 0, 3 and 7. Serial echocardiography was performed, and hearts were harvested on day 10. UTMC treatment of CFs with miR-29b-MB increased miR-29b and decreased fibrotic transcripts compared with NC-MB treatment. In vivo UTMC + NC-MB led to increased LV mass, reduction in cardiac function and increase in fibrotic markers, demonstrating ANGI II-induced adverse cardiac remodeling. Mice treated with UTMC + miR-29b-MB had preservation of cardiac function, downregulation of cardiac fibrillin and trends of lower COL1A1, COL1A2 and COL3 mRNA and decreased cardiac α-smooth muscle protein. UTMC-mediated delivery of miR-29b mimic blunts expression of fibrosis markers and preserves LV function in ANG II-induced cardiac fibrosis. [ABSTRACT FROM AUTHOR]

The aim of the present study is to investigate the ameliorative potential of the aqueous extract of Indigofera tinctoria (IT) in aging-induced inflammation and its associated cardiac hypertrophy and fibrosis. Young (3-month-old) and aged (24–26-month-old) male Wistar albino rats were grouped into young control, aged control, aged + IT, and young + IT. The animals in the supplementary groups received 200 mg/kg BWT of aqueous extract of IT orally once a day for 21 days. Aged animals showed prolonged QT interval and increased weight and volume of the heart with a thickening ventricular wall. Infiltration of leukocytes and increased cardiomyocyte diameter and decreased numerical density along with cardiomyocyte apoptosis and increased collagen accumulation were also seen in aged myocardium when compared to the young. The expression profile of various pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α, NFκB, and iNOS was increased with a concomitant reduction in IL-10 expression in the aged compared to the young. In addition, a marked increase in ROS generation, TGF-β, and α-SMA levels is evident in the aged myocardium. These pathological changes were greatly reversed in aged animals supplemented with IT. Furthermore, the aged + IT group showed repression of pro-inflammatory markers with a subsequent increase in IL-10 expression. Contrarily, no marked changes were observed between young and young + IT groups. Taken together, it is concluded that the aqueous extract of Indigofera tinctoria suppresses cardiac fibrosis and hypertrophy by repressing the inflammation and its associated activation of TGFβ and myofibroblast conversion. [ABSTRACT FROM AUTHOR]

Background: Tumour necrosis factor superfamily protein 14 (TNFSF14), also called LIGHT, is an important regulator of immunological and fibrosis diseases. However, its specific involvement in cardiac fibrosis and atrial fibrillation (AF) has not been fully elucidated. The objective of this study is to examine the influence of LIGHT on the development of myocardial fibrosis and AF. Methods: PCR arrays of peripheral blood mononuclear cells (PBMCs) from patients with AF and sinus rhythm was used to identify the dominant differentially expressed genes, followed by ELISA to evaluate its serum protein levels. Morphological, functional, and electrophysiological changes in the heart were detected in vivo after the tail intravenous injection of recombinant LIGHT (rLIGHT) in mice for 4 weeks. rLIGHT was used to stimulate bone marrow-derived macrophages (BMDMs) to prepare a macrophage-conditioned medium (MCM) in vitro. Then, the MCM was used to culture mouse cardiac fibroblasts (CFs). The expression of relevant proteins and genes was determined using qRT-PCR, western blotting, and immunostaining. Results: The mRNA levels of LIGHT and TNFRSF14 were higher in the PBMCs of patients with AF than in those of the healthy controls. Additionally, the serum protein levels of LIGHT were higher in patients with AF than those in the healthy controls and were correlated with left atrial reverse remodelling. Furthermore, we demonstrated that rLIGHT injection promoted macrophage infiltration and M2 polarisation in the heart, in addition to promoting atrial fibrosis and AF inducibility in vivo, as detected with MASSON staining and atrial burst pacing respectively. RNA sequencing of heart samples revealed that the PI3Kγ/SGK1 pathway may participate in these pathological processes. Therefore, we confirmed the hypothesis that rLIGHT promotes BMDM M2 polarisation and TGB-β1 secretion, and that this process can be inhibited by PI3Kγ and SGK1 inhibitors in vitro. Meanwhile, increased collagen synthesis and myofibroblast transition were observed in LIGHT-stimulated MCM-cultured CFs and were ameliorated in the groups treated with PI3Kγ and SGK1 inhibitors. Conclusion: LIGHT protein levels in peripheral blood can be used as a prognostic marker for AF and to evaluate its severity. LIGHT promotes cardiac fibrosis and AF inducibility by promoting macrophage M2 polarisation, wherein PI3Kγ and SGK1 activation is indispensable. [ABSTRACT FROM AUTHOR]

The aim of the present study is to investigate the ameliorative potential of the aqueous extract of Indigofera tinctoria (IT) in aging-induced inflammation and its associated cardiac hypertrophy and fibrosis. Young (3-month-old) and aged (24–26-month-old) male Wistar albino rats were grouped into young control, aged control, aged + IT, and young + IT. The animals in the supplementary groups received 200 mg/kg BWT of aqueous extract of IT orally once a day for 21 days. Aged animals showed prolonged QT interval and increased weight and volume of the heart with a thickening ventricular wall. Infiltration of leukocytes and increased cardiomyocyte diameter and decreased numerical density along with cardiomyocyte apoptosis and increased collagen accumulation were also seen in aged myocardium when compared to the young. The expression profile of various pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α, NFκB, and iNOS was increased with a concomitant reduction in IL-10 expression in the aged compared to the young. In addition, a marked increase in ROS generation, TGF-β, and α-SMA levels is evident in the aged myocardium. These pathological changes were greatly reversed in aged animals supplemented with IT. Furthermore, the aged + IT group showed repression of pro-inflammatory markers with a subsequent increase in IL-10 expression. Contrarily, no marked changes were observed between young and young + IT groups. Taken together, it is concluded that the aqueous extract of Indigofera tinctoria suppresses cardiac fibrosis and hypertrophy by repressing the inflammation and its associated activation of TGFβ and myofibroblast conversion. [ABSTRACT FROM AUTHOR]

A significant cardiac complication of diabetes is cardiomyopathy, a form of ventricular dysfunction that develops independently of coronary artery disease, hypertension and valvular diseases, which may subsequently lead to heart failure. Several structural features underlie the development of diabetic cardiomyopathy and eventual diabetes‐induced heart failure. Pathological cardiac fibrosis (interstitial and perivascular), in addition to capillary rarefaction and myocardial apoptosis, are particularly noteworthy. Sex differences in the incidence, development and presentation of diabetes, heart failure and interstitial myocardial fibrosis have been identified. Nevertheless, therapeutics specifically targeting diabetes‐associated cardiac fibrosis remain lacking and treatment approaches remain the same regardless of patient sex or the co‐morbidities that patients may present. This review addresses the observed anti‐fibrotic effects of newer glucose‐lowering therapies and traditional cardiovascular disease treatments, in the diabetic myocardium (from both preclinical and clinical contexts). Furthermore, any known sex differences in these treatment effects are also explored. LINKED ARTICLES: This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc [ABSTRACT FROM AUTHOR]

Aims Cardiac fibrosis drives the progression of heart failure in ischaemic and hypertrophic cardiomyopathy. Therefore, the development of specific anti-fibrotic treatment regimens to counteract cardiac fibrosis is of high clinical relevance. Hence, this study examined the presence of persistent fibroblast activation during longstanding human heart disease at a single-cell resolution to identify putative therapeutic targets to counteract pathological cardiac fibrosis in patients. Methods and results We used single-nuclei RNA sequencing with human tissues from two samples of one healthy donor, and five hypertrophic and two failing hearts. Unsupervised sub-clustering of 7110 nuclei led to the identification of 7 distinct fibroblast clusters. De-convolution of cardiac fibroblast heterogeneity revealed a distinct population of human cardiac fibroblasts with a molecular signature of persistent fibroblast activation and a transcriptional switch towards a pro-fibrotic extra-cellular matrix composition in patients with established cardiac hypertrophy and heart failure. This sub-cluster was characterized by high expression of POSTN , RUNX1 , CILP , and a target gene adipocyte enhancer-binding protein 1 (AEBP1) (all P < 0.001). Strikingly, elevated circulating AEBP1 blood level were also detected in a validation cohort of patients with confirmed cardiac fibrosis and hypertrophic cardiomyopathy by cardiac magnetic resonance imaging (P < 0.01). Since endogenous AEBP1 expression was increased in patients with established cardiac hypertrophy and heart failure, we assessed the functional consequence of siRNA-mediated AEBP1 silencing in human cardiac fibroblasts. Indeed, AEBP1 silencing reduced proliferation, migration, and fibroblast contractile capacity and α-SMA gene expression, which is a hallmark of fibroblast activation (all P < 0.05). Mechanistically, the anti-fibrotic effects of AEBP1 silencing were linked to transforming growth factor-beta pathway modulation. Conclusion Together, this study identifies persistent fibroblast activation in patients with longstanding heart disease, which might be detected by circulating AEBP1 and therapeutically modulated by its targeted silencing in human cardiac fibroblasts. [ABSTRACT FROM AUTHOR]

Background: Myocardial fibrosis has recently been proposed as one of the contributing factors to the diverse pathogenicity of cardiomyopathy in sickle cell disease. Objective: In this study, cardiac fibrosis and subclinical cardiac changes in children with sickle cell disease were evaluated using cardiac magnetic resonance imaging (MRI), tissue Doppler echocardiography and serum galectin-3. Materials and methods: The study included 34 children with sickle cell disease who were compared with a similar number of healthy controls. Cardiac MRI was used to evaluate late gadolinium enhancement, native T1 mapping, extracellular volume, and T2* for estimation of iron load. Cardiac function and myocardial performance index (MPI, evaluated by tissue Doppler echocardiography) and serum galectin-3 were compared to controls. Results: The mean age of the included patients was 13.3 ± 3.2 years. Myocardial iron load by T2* was normal. The mean level of extracellular volume (35.41 ± 5.02%) was significantly associated with the frequency of vaso-occlusive crises (P = 0.017) and negatively correlated with hemoglobin levels (P = 0.005). Galectin-3 levels were significantly higher among cases than controls (P = 0.00), at a cutoff value on the receiver operating characteristic curve of 6.5 ng/ml, sensitivity of 82.5% and specificity of 72.8%. The extracellular volume was significantly higher in cases, with a MPI > 0.4. Conclusion: Diffuse interstitial myocardial fibrosis can be detected early in children with sickle cell disease using T1 mapping and is associated with a high frequency of vaso-occlusive crisis. MPI of the left ventricle and serum galectin-3 are recommended screening tools for subclinical cardiac abnormalities. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is a remodeling process of the cardiac interstitium, characterized by abnormal metabolism of the extracellular matrix, excessive accumulation of collagen fibers, and scar tissue hyperplasia. Persistent activation and transdifferentiation into myofibroblasts of cardiac fibroblasts promote the progression of fibrosis. Transforming growth factor-β1 (TGF-β1) is a pivotal factor in cardiac fibrosis. Latency-associated peptide (LAP) is essential for activating TGF-β1 and its binding to the receptor. Thus, interference with TGF-β1 and the signaling pathways using LAP may attenuate cardiac fibrosis. Recombinant full-length and truncated LAP were previously constructed, expressed, and purified. Their effects on cardiac fibrosis were investigated in isoproterenol (ISO)-induced cardiac fibroblasts (CFs) and C57BL/6 mice. The study showed that LAP and tLAP inhibited ISO-induced CF activation, inflammation, and fibrosis, improved cardiac function, and alleviated myocardial injury in ISO-induced mice. LAP and tLAP alleviated the histopathological alterations and inhibited the elevated expression of inflammatory and fibrosis-related markers in cardiac tissue. In addition, LAP and tLAP decreased the ISO-induced elevated expression of TGF-β, αvβ3, αvβ5, p-Smad2, and p-Smad3. The study indicated that LAP and tLAP attenuated ISO-induced cardiac fibrosis via suppressing TGF-β/Smad pathway. This study may provide a potential approach to alleviate cardiac fibrosis. Key points: • LAP and tLAP inhibited ISO-induced CF activation, inflammation, and fibrosis. • LAP and tLAP improved cardiac function and alleviated myocardial injury, inflammation, and fibrosis in ISO-induced mice. • LAP and tLAP attenuated cardiac fibrosis via suppressing TGF-β/Smad pathway. [ABSTRACT FROM AUTHOR]

Diosmetin‐7‐O‐β‐D‐glucopyranoside (Diosmetin‐7‐O‐glucoside) is a natural flavonoid glycoside known to have a therapeutic application for cardiovascular diseases. Cardiac fibrosis is the main pathological change in the end stage of cardiovascular diseases. Endothelial‐mesenchymal transformation (EndMT) induced by endoplasmic reticulum stress (ER stress) via Src pathways is involved in the process of cardiac fibrosis. However, it is unclear whether and how diosmetin‐7‐O‐glucoside regulates EndMT and ER stress to treat cardiac fibrosis. In this study, molecular docking results showed that diosmetin‐7‐O‐glucoside bound well to ER stress and Src pathway markers. Diosmetin‐7‐O‐glucoside suppressed cardiac fibrosis induced by isoprenaline (ISO) and reduced the levels of EndMT, ER stress in mice heart. Primary cardiac microvascular endothelial cells (CMECs) were induced by transforming growth factor‐β1 (TGF‐β1) to perform EndMT. Diosmetin‐7‐O‐glucoside could effectively regulate EndMT and diminish the accumulation of collagen I and collagen III. We also showed that the tube formation in CMECs was restored, and the capacity of migration was partially inhibited. Diosmetin‐7‐O‐glucoside also ameliorated ER stress through the three unfolded protein response branches, as evidenced by organelle structure in transmission electron microscopy images and the expression of protein biomarkers like the glucose‐regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP). Further analysis showed that diosmetin‐7‐O‐glucoside could suppress the expression level of Src phosphorylation, then block EndMT with the maintenance of endothelial appearance and endothelial marker expression. These results suggested that the diosmetin‐7‐O‐glucoside can regulate EndMT through ER stress, at least in part via Src‐dependent pathways. [ABSTRACT FROM AUTHOR]

Background: Aortic stenosis (AS) is one of the most common cardiac diseases and major cause of morbidity and mortality in the elderly. Transcatheter aortic valve implantation (TAVI) is performed in such patients with symptomatic severe AS and reduces mortality for the majority of these patients. However, a significant percentage dies within the first two years after TAVI, such that there is an interest to identify parameters, which predict outcome and could guide pre-TAVI patient selection. High levels of cardiac fibrosis have been identified as such independent predictor of cardiovascular mortality after TAVI. Promoter hypermethylation commonly leads to gene downregulation, and the Iroquois homeobox 3 (IRX3) gene was identified in a genome-wide transcriptome and methylome to be hypermethylated and downregulated in AS patients. In a well-described cohort of 100 TAVI patients in which cardiac fibrosis levels were quantified histologically in cardiac biopsies, and which had a follow-up of up to two years, we investigated if circulating methylated DNA of IRX3 in the peripheral blood is associated with cardiac fibrosis and/or mortality in AS patients undergoing TAVI and thus could serve as a biomarker to add information on outcome after TAVI. Results: Patients with high levels of methylation in circulating IRX3 show a significantly increased survival as compared to patients with low levels of IRX3 methylation indicating that high peripheral IRX3 methylation is associated with an improved outcome. In the multivariable setting, peripheral IRX3 methylation acts as an independent predictor of all-cause mortality. While there is no significant correlation of levels of IRX3 methylation with cardiac death, there is a significant but very weak inverse correlation between circulating IRX3 promoter methylation level and the amount of cardiac fibrosis. Higher levels of peripheral IRX3 methylation further correlated with decreased cardiac IRX3 expression and vice versa. Conclusions: High levels of IRX3 methylation in the blood of AS patients at the time of TAVI are associated with better overall survival after TAVI and at least partially reflect myocardial IRX3 expression. Circulating methylated IRX3 might aid as a potential biomarker to help guide both pre-TAVI patient selection and post-TAVI monitoring. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Galectin-3 is a cardiac biomarker for heart failure in humans. However, it has not been investigated in dogs with naturally occurring heart disease. This study aimed to compare plasma galectin-3 concentration in healthy dogs and those with myxomatous mitral valve disease (MMVD) and explore the potential association of galectin-3 with other cardiac biomarkers, inflammatory cytokines, echocardiographic estimates, and dog characteristics. ANIMALS: 10 healthy dogs and 30 dogs with MMVD were prospectively recruited. PROCEDURES: In this case-control study, plasma galectin-3, inflammatory cytokines, echocardiographic estimates, and other cardiac biomarkers were measured, and dog characteristics were recorded. RESULTS: Plasma galectin-3 concentration was significantly higher in dogs with MMVD (2.94 [interquartile range, 1.61 to 5.20] ng/mL) than in healthy controls (1.56 [0.69 to 1.84] ng/mL, P = .009). Logistic regression analysis revealed that galectin-3 concentration and age predicted the presence of MMVD (predictive accuracy = 90.0%, P < .05). A cut-off value = 1.9 ng/mL for galectin-3 differentiated healthy dogs from dogs with MMVD (70% sensitivity; 90% specificity AUC, 0.77; P = .01). CLINICAL RELEVANCE: Plasma galectin-3 concentration was higher in dogs with MMVD than in healthy dogs, indicating that it is a novel cardiac biomarker in dogs with MMVD although there was no significant difference between MMVD stages. [ABSTRACT FROM AUTHOR]

The increasing burden of heart failure with preserved ejection fraction (HFpEF) has become a global health problem. HFpEF is characterized by systematic inflammation, cardiac metabolic remodeling, and fibrosis. Eosinophils act as an essential but generally overlooked subgroup of white blood cells, which participate in cardiac fibrosis, as reported in several recent studies. Herein, we explored the role of eosinophils in a "two‐hit" preclinical HFpEF model. The peripheral eosinophil counts were comparable between the normal chow and HFpEF mice. Deficiency of eosinophils failed to alter the phenotype of HFpEF. Conclusively, the development of HFpEF is independent of eosinophils in terms of the functional, biochemical, and histological results. [ABSTRACT FROM AUTHOR]

Cardiac fibrosis is closely associated with multiple heart diseases, which are a prominent health issue in the global world. Neurohormones and cytokines play indispensable roles in cardiac fibrosis. Many signaling pathways participate in cardiac fibrosis as well. Cardiac fibrosis is due to impaired degradation of collagen and impaired fibroblast activation, and collagen accumulation results in increasing heart stiffness and inharmonious activity, leading to structure alterations and finally cardiac function decline. Herbal plants have been applied in traditional medicines for thousands of years. Because of their naturality, they have attracted much attention for use in resisting cardiac fibrosis in recent years. This review sheds light on several extracts from herbal plants, which are promising therapeutics for reversing cardiac fibrosis. [ABSTRACT FROM AUTHOR]

Chronic intermittent hypoxia (CIH) mimicking obstructive sleep apnea elicits divergent outcomes in the cardiovascular systems. The effect of renal denervation (RDN) on the heart during CIH remains unclear. We aimed to explore the effect of RDN on cardiac remodelling in rats exposed to CIH and to discuss the underlying mechanisms. Adult Sprague Dawley rats were divided into four groups: control, control+RDN, CIH (CIH exposure for 6 weeks, nadir of 5%–7% to peak of 21% O2, 20 cycles/h, 8 h/day) and CIH+ RDN group. Echocardiography, cardiac fibrosis, left ventricle (LV) expressions of nuclear factor‐E2‐related factor 2 (Nrf2)/heme oxygenase‐1 (HO‐1) pathway and inflammatory factors were tested at the end of the study. Cardiac structural remodelling and dysfunction were induced by CIH and attenuated by RDN. Myocardial fibrosis was more severe in the CIH group than in the control group and improved in the CIH + RDN group. Sympathetic activity reflected by tyrosine hydroxylase (TH) expression and noradrenaline were significantly elevated after CIH but blunted by RDN. CIH downregulated LV protein expressions of Nrf2 and HO‐1, which was activated by RDN. The downstream of Nrf2/HO‐1, such as NQO1 and SOD expression, elevated following RDN. RDN also decreased the mRNA expression of IL‐1β and IL‐6. Notably, control+RDN did not affect cardiac remodelling and Nrf2/HO‐1 compared with the control. Taken together, we found that RDN exerted cardio‐protective effects in a rat model of CIH involving Nrf2/HO‐1 pathway and inflammation. [ABSTRACT FROM AUTHOR]

Introduction: Thymoquinone (TQ) is one of the active ingredients in herbal plants such as Nigella sativa which has antioxidant and anti-inflammatory properties thus may inhibits cardiac fibrosis formation. This study aims to determine the effectiveness of Thymoquinone as a cardioprotective agent in suppressing the extent of fibrosis in Wistar rats induced with lipopolysaccharide (LPS). Methods: This post-test only control study used 30 Wistar rats which were divided into 5 groups: saline, LPS-induced cardiac fibrosis, LPS-induced cardiac fibrosis treated with TQ 10 mg/mL, LPS-induced cardiac fibrosis treated with TQ 20 mg/mL, and LPS-induced cardiac fibrosis treated with TQ 40 mg/mL. Serum IL-6, GSH, and cTnT levels were measured using ELISA, and Mason's trichrome staining was used to assess myocardial fibrosis. Results: The LPS10+TQ20 and LPS10+TQ40 groups exhibited significantly lower levels of IL-6 compared to the LPS10+TQ10 group (p < 0.05). GSH levels did not show a significant decrease in the TQ groups across different doses (p=0.771). The TQ-treated group demonstrated lower cTnT levels compared to the LPS-only group (p<0.05). Thymoquinone treatment resulted in reduced fibrosis area compared to the LPS10 group (p<0.05). Conclusions: TQ has a promising cardioprotective effect on the formation of cardiac fibrosis in Wistar rats induced with LPS. [ABSTRACT FROM AUTHOR]

Introduction: Attenuating cardiac fibroblasts activation contributes to reducing excessive extracellular matrix deposition and cardiac structural remodeling in hypertensive hearts. Acacetin plays a protective role in doxorubicin-induced cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to investigate the potential molecular mechanisms underlying the protective role of acacetin on hypertension-induced cardiac fibrosis. Methods: Echocardiography, histopathological methods, and Western blotting techniques were used to evaluate the anti-fibrosis effects in spontaneous hypertensive rat (SHR) which were daily intragastrically administrated with acacetin (10 mg/kg and 20 mg/kg) for 6 weeks. Angiotensin II (Ang II) was used to induce cellular fibrosis in human cardiac fibroblasts (HCFs) in the absence and presence of acacetin treatment for 48 h. Results: Acacetin significantly alleviated hypertension-induced increase in left ventricular (LV) posterior wall thickness and LV mass index in SHR. The expressions of collagen-1, collagen-III, and alpha-smooth muscle actin (α-SMA) were remarkedly decreased after treatment with acacetin (n = 6, p < 0.05). In cultured HCFs, acacetin significantly attenuated Ang II-induced migration and proliferation (n = 6, p < 0.05). Moreover, acacetin substantially inhibited Ang II-induced upregulation of collagen-1 and collagen-III (n = 6, p < 0.05) and downregulated the expression of alpha-SMA in HCFs. Additionally, acacetin decreased the expression of TGF-β1, p-Smad3/Smad3, and p-AKT and p-mTOR but increased the expression of Smad7 (n = 6, p < 0.05). Further studies found that acacetin inhibited TGF-β1 agonist SRI and AKT agonist SC79 caused fibrotic effect. Conclusion: Acacetin inhibits the hypertension-associated cardiac fibrotic processes through regulating TGF-β/Smad3, AKT/mTOR signal transduction pathways. [ABSTRACT FROM AUTHOR]

Epigenetic mechanisms and cell crosstalk have been shown to play important roles in the initiation and progression of cardiac fibrosis. This review article aims to provide a thorough overview of the epigenetic mechanisms involved in fibroblast regulation. During fibrosis, fibroblast epigenetic regulation encompasses a multitude of mechanisms, including DNA methylation, histone acetylation and methylation, and chromatin remodeling. These mechanisms regulate the phenotype of fibroblasts and the extracellular matrix composition by modulating gene expression, thereby orchestrating the progression of cardiac fibrosis. Moreover, cardiac fibrosis disrupts normal cardiac function by imposing myocardial mechanical stress and compromising cardiac electrical conduction. This review article also delves into the intricate crosstalk between cardiomyocytes and non-cardiomyocytes in the heart. A comprehensive understanding of the mechanisms governing epigenetic regulation and cell crosstalk in cardiac fibrosis is critical for the development of effective therapeutic strategies. Further research is warranted to unravel the precise molecular mechanisms underpinning these processes and to identify potential therapeutic targets. [ABSTRACT FROM AUTHOR]

(1) Background: Heart failure (HF) is the final stage of multiple cardiac diseases, which have now become a severe public health problem worldwide. β-Adrenergic receptor (β-AR) overactivation is a major pathological factor associated with multiple cardiac diseases and mediates cardiac fibrosis and inflammation. Previous research has demonstrated that Bruton's tyrosine kinase (BTK) mediated cardiac fibrosis by TGF-β related signal pathways, indicating that BTK was a potential drug target for cardiac fibrosis. Zanubrutinib, a second-generation BTK inhibitor, has shown anti-fibrosis effects in previous research. However, it is unclear whether Zanubrutinib can alleviate cardiac fibrosis induced by β-AR overactivation; (2) Methods: In vivo: Male C57BL/6J mice were treated with or without the β-AR agonist isoproterenol (ISO) to establish a cardiac fibrosis animal model; (3) Results: In vivo: Results showed that the BTK inhibitor Zanubrutinib (ZB) had a great effect on cardiac fibrosis and inflammation induced by β-AR. In vitro: Results showed that ZB alleviated β-AR-induced cardiac fibroblast activation and macrophage pro-inflammatory cytokine production. Further mechanism studies demonstrated that ZB inhibited β-AR-induced cardiac fibrosis and inflammation by the BTK, STAT3, NF-κB, and PI3K/Akt signal pathways both in vivo and in vitro; (4) Conclusions: our research provides evidence that ZB ameliorates β-AR-induced cardiac fibrosis and inflammation. [ABSTRACT FROM AUTHOR]

Aims Heart failure is a condition with high mortality rates, and there is a lack of therapies that directly target maladaptive changes in the extracellular matrix (ECM), such as fibrosis. We investigated whether the ECM enzyme known as A disintegrin and metalloprotease with thrombospondin motif (ADAMTS) 4 might serve as a therapeutic target in treatment of heart failure and cardiac fibrosis. Methods and results The effects of pharmacological ADAMTS4 inhibition on cardiac function and fibrosis were examined in rats exposed to cardiac pressure overload. Disease mechanisms affected by the treatment were identified based on changes in the myocardial transcriptome. Following aortic banding, rats receiving an ADAMTS inhibitor, with high inhibitory capacity for ADAMTS4, showed substantially better cardiac function than vehicle-treated rats, including ∼30% reduction in E/e′ and left atrial diameter, indicating an improvement in diastolic function. ADAMTS inhibition also resulted in a marked reduction in myocardial collagen content and a down-regulation of transforming growth factor (TGF)-β target genes. The mechanism for the beneficial effects of ADAMTS inhibition was further studied in cultured human cardiac fibroblasts producing mature ECM. ADAMTS4 caused a 50% increase in the TGF-β levels in the medium. Simultaneously, ADAMTS4 elicited a not previously known cleavage of TGF-β-binding proteins, i.e. latent-binding protein of TGF-β and extra domain A-fibronectin. These effects were abolished by the ADAMTS inhibitor. In failing human hearts, we observed a marked increase in ADAMTS4 expression and cleavage activity. Conclusion Inhibition of ADAMTS4 improves cardiac function and reduces collagen accumulation in rats with cardiac pressure overload, possibly through a not previously known cleavage of molecules that control TGF-β availability. Targeting ADAMTS4 may serve as a novel strategy in heart failure treatment, in particular, in heart failure with fibrosis and diastolic dysfunction. [ABSTRACT FROM AUTHOR]

Cardiac hypertrophy is an adaptive response to various pathological insults, including hypertension. However, sustained hypertrophy can cause impaired calcium regulation, cardiac dysfunction, and remodeling, accompanied by cardiac fibrosis. Our previous study identified miR-25 as a regulator of SERCA2a, and found that the inhibition of miR-25 improved cardiac function and reduced fibrosis by restoring SERCA2a expression in a murine heart failure model. However, the precise mechanism underlying the reduction in fibrosis following miR-25 inhibition remains unclear. Therefore, we postulate that miR-25 may have additional targets that contribute to regulating cardiac fibrosis. Using in silico analysis, Krüppel-like factor 4 (KLF4) was identified as an additional target of miR-25. Further experiments confirmed that KLF4 was directly targeted by miR-25 and that its expression was reduced by long-term treatment with Angiotensin II, a major hypertrophic inducer. Subsequently, treatment with an miR-25 inhibitor alleviated the cardiac dysfunction, fibrosis, and inflammation induced by Angiotensin II (Ang II). These findings indicate that inhibiting miR-25 not only enhances calcium cycling and cardiac function via SERCA2a restoration but also reduces fibrosis by restoring KLF4 expression. Therefore, targeting miR-25 may be a promising therapeutic strategy for treating hypertensive heart diseases. [ABSTRACT FROM AUTHOR]

Background: Genetics evidences have long linked mosaic loss of Y-chromosome (mLOY) in peripheral leukocytes with a wide range of male age-associated diseases. However, a lack of cellular and molecular mechanistic explanations for this link has limited further investigation into the relationship between mLOY and male age-related disease. Excitingly, Sano et al. have provided the first piece of evidence directly linking mLOY to cardiac fibrosis through mLOY enriched profibrotic transforming growth factor β1 (TGF-β1) regulons in hematopoietic macrophages along with suppressed interleukin-1β (IL-1β) proinflammatory regulons. The results of this novel finding can be extrapolated to other disease related to mLOY, such as cancer, cardiac disease, and age-related macular degeneration. Results: Sano et al. used a CRISPR-Cas9 gRNAs gene editing induced Y-chromosome ablation mouse model to assess results of a UK biobank prospective analysis implicating the Y-chromosome in male age-related disease. Using this in vivo model, Sano et al. showed that hematopoietic mLOY accelerated cardiac fibrosis and heart failure in male mice through profibrotic pathways. This process was linked to monocyte-macrophage differentiation during hematopoietic development. Mice confirmed to have mLOY in leukocytes, by loss of Y-chromosome genes Kdm5d, Uty, Eif2s3y, and Ddx3y, at similar percentages to the human population were shown to have accelerated rates of interstitial and perivascular fibrosis and abnormal echocardiograms. These mice also recovered poorly from the transverse aortic constriction (TAC) model of heart failure and developed left ventricular dysfunction at higher rates. This was attributed to aberrant proliferation of cardiac MEF-SK4 + fibroblasts promoted by mLOY macrophages enriched in profibrotic regulons and lacking in proinflammatory regulons. These pro-fibrotic macrophages localized to heart and eventually resulted in cardiac fibrosis via enhanced TGF-β1 and suppressed IL-1β signaling. Furthermore, treatment of mLOY mice with TGFβ1 neutralizing antibody was able to improve their cardiac function. This study by Sano et al. was able to provide a causative link between the known association between mLOY and male cardiac disease morbidity and mortality for the first time, and thereby provide a new target for improving human health. Conclusions: Using a CRISPR-Cas9 induced Y-chromosome ablation mouse model, Sano et al. has proven mosaic loss of Y-chromosome in peripheral myeloid cells to have a causative effect on male mobility and mortality due to male age-related cardiac disease. They traced the mechanism of this effect to hyper-expression of the profibrotic TGF-β1 and reduced pro-inflammatory IL-1β signaling, attenuation of which could provide another potential strategy in improving outcomes against age-related diseases in men. [ABSTRACT FROM AUTHOR]