Cardiac fibrosis: Myofibroblast-mediated pathological regulation and drug delivery strategies

Role of macrophages in peritoneal dialysis-associated peritoneal fibrosis

Peritoneal dialysis (PD) can be used as renal replacement therapy when chronic kidney disease (CKD) progresses to end-stage renal disease. However, peritoneal fibrosis (PF) is a major cause of PD failure. Studies have demonstrated that PD fluid contains a significantly larger numbers of macrophages compared with the healthy individuals. During PD, macrophages can secrete cytokines to keep peritoneal tissue in sustained low-grade inflammation, and participate in the regulation of fibrosis-related signaling pathways, such as NF-κB, TGF-β/Smad, IL4/STAT6, and PI3K/AKT. A series of basic pathological changes occurs in peritoneal tissues, including epithelial mesenchymal transformation, overgeneration of neovasculature, and abnormal deposition of extracellular matrix. This review focuses on the role of macrophages in promoting PF during PD, summarizes the targets of macrophage-related inhibition of fibrosis, and provides new ideas for clinical research on delaying PF, maintaining the function and integrity of peritoneum, prolonging duration of PD as a renal replacement modality, and achieving longer survival in CKD patients.

Systematic identification of SNCA as a key gene in ischemic cardiomyopathy via integrated weighted gene co-expression network analysis and experimental validation

Ischemic cardiomyopathy (ICM) is associated with high mortality and hospitalization rates, and current treatments are suboptimal. The aim of this research was to identify novel therapeutic targets for ICM. The datasets GSE57338 and GSE5406 were obtained from the Gene Expression Omnibus (GEO) database. Gene modules were constructed using weighted gene co-expression network analysis (WGCNA), and the three relevant modules associated with ICM were identified. The biological functions and signaling pathways of the genes in these modules were further explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Protein-protein interaction (PPI) networks were employed to identify hub genes within these modules. Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression was performed to establish gene models, and 16 genes associated with left ventricular ejection fraction (LVEF) in ICM were identified. The genes were validated in heart tissues from human using quantitative real-time polymerase chain reaction (qRT-PCR). Among them, growth factor receptor-bound protein 14 (GRB14), ubiquitin C-terminal hydrolase L1 (UCHL1), and synuclein alpha (SNCA) were identified as key genes significantly associated with ICM. Additionally, key genes correlated with immune and stromal cell-related types were screened using xCell. In vivo and in vitro experiments demonstrated that inhibiting SNCA could improve cardiac dysfunction, inflammatory infiltration, and fibrosis in ICM. In conclusion, this study identified 16 genes closely related to LVEF and revealed that SNCA was a key gene in ICM, providing potential biomarkers and therapeutic targets for ICM.

Fibroblast activation protein-targeted chimeric antigen-receptor-modified NK cells alleviate cardiac fibrosis

Cardiac fibrosis (CF) is a common pathophysiological process in the development of various cardiovascular diseases, during which many cardiac fibroblasts undergo myofibroblast transdifferentiation. Fibroblast activation protein (FAP) can serve as a specific target for myofibroblasts, and chimeric antigen receptor (CAR)-based therapy is a promising immunotherapy strategy. In this study, we attempted to construct CAR natural killer (NK) cells that target FAP and explored their potential therapeutic role in CF. Our results suggested FAP CAR-NK-92 cells can specifically recognize and kill FAP+ cells in vitro. In addition, compared with parental NK-92 cells, FAP CAR-NK cells cocultured with FAP HEK-293 T cells presented increased cytotoxicity, cytokine secretion, and degranulation, indicating an effect-to-target ratio dependence. Coculturing FAP CAR-NK cells with mouse cardiac fibroblast lines (MCFs) eliminated the activated fibroblasts, reduced fibrosis-related protein secretion, and significantly reversed the contractile phenotype of myofibroblasts, which is characterized by alpha-smooth muscle actin (α-SMA) and stress fiber formation. Intravenous injection of FAP CAR-NK cells in mice 7 days after Ang II/PE-induced injury significantly improved cardiac function and reduced fibrosis. In terms of the killing mechanism, the early apoptosis rate of target cells was significantly increased, the antiapoptotic protein Bcl-2 was significantly decreased, and the proapoptotic proteins Bax and Caspase 3 were markedly increased. Our findings demonstrate that FAP CAR-NK-92 cells can specifically recognize FAP+ target cells and exert potent anti-fibrotic effects both in vitro and in vivo. Therefore, FAP CAR-NK-92 cells could be considered an effective therapeutic option for CF patients.

The theatrics of collagens in the myocardium: the supreme architect of the fibrotic heart

Heart failure (HF) mediated by cardiac fibrosis (CF) is characterized by an excessive accumulation of collagen-based extracellular matrix (ECM) in the myocardium. CF is a common pathophysiological condition in many heart diseases and can be distinctly categorized into two types: replacement and interstitial. In ischemic heart diseases, sudden loss of cardiomyocytes leads to the replacement of CF to prevent ventricular rupture. In contrast, excessive collagen deposition in the interstitial space between cardiomyocytes (often in response to pressure overload, chronic cardiac stress, hypertension, etc.) is termed interstitial CF. The progression of HF due to cardiac fibrosis is mainly driven by compromised diastolic function, resulting from increased stiffness of the heart wall muscle due to collagen-based scar formation. Increased myocardial stiffness is primarily catalyzed by the differential cross linking of deposited collagens forming the scar in the fibrotic heart. Although collagen deposition remained a hallmark of fibrosis, the pathophysiological progression due to biochemical alterations and mechanistic discrepancy of collagens across cardiac fibrosis subtypes remains elusive. With the advent of next-generation RNA sequencing and high-resolution mass spectrometry, mechanistic insights into collagen-mediated scar maturation have gained impetus. A deeper understanding of the spatiocellular transcriptional heterogeneity and site-specific collagen posttranslational modifications (PTMs) in maneuvering ECM remodeling is gaining attention. The unexplored mechanisms of posttranslational modifications and subsequent collagen cross linking in various cardiac fibrosis may provide the prime target for therapeutic interventions. This review comprehensively summarizes the detailed pattern, role, signaling, and mechanical contributions of different collagens and their PTMs, including cross-linking patterns as newer therapeutic regimens during cardiac fibrosis.

Long-term prognostic value of CRP-albumin-lymphocyte index in elderly patients with heart failure with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a complex and heterogeneous clinical condition characterized by the interplay of malnutrition and immune inflammation, especially in elderly patients. The CRP-Albumin-Lymphocyte (CALLY) index, a novel composite indicator reflecting immune inflammation and nutritional status, has not yet been validated as a prognostic tool in elderly patients with HFpEF.

METHODS

This retrospective study included 320 elderly patients hospitalized at the Air Force Medical Center from October 2016 to April 2019 due to HFpEF. Patients were stratified into the all-cause mortality and the survival groups according to follow-up outcomes. Kaplan-Meier analysis and Cox regression were performed to identify risk factors associated with poor prognosis. Additionally, we constructed and evaluated a nomogram based on the CALLY index to predict survival rates.

RESULTS

During the follow-up period, 137 cases (42.81 %) of patients experienced all-cause mortality. Kaplan-Meier survival curves and Cox regression analysis revealed that a lower CALLY index (HR 0.811, 95 % CI 0.714-0.921, P = 0.001) was independently associated with adverse prognosis in elderly patients with HFpEF. The nomogram incorporating the CALLY index exhibited robust predictive performance for predicting 1-year, 3-year, and 5-year survival outcomes.

CONCLUSION

Our findings demonstrate that the CALLY index is an independent predictor of long-term mortality in elderly patients with HFpEF. The developed nomogram incorporating the CALLY index could effectively predict survival probabilities.

Cardiotoxicity Beyond Cardiomyocytes-Focus on the Role of Cardiac Fibroblasts and Endothelial Cells

INTRODUCTION

Anti-cancer treatments frequently have serious adverse effects on the cardiovascular system. Understanding the mechanisms underlying these cancer therapy-related cardiovascular toxicities is essential for their prevention and potential treatment. While research often centres on cardiomyocyte damage as the primary cause of cardiac injury, the roles of cardiac fibroblasts and endothelial cells are often neglected. In this study, we aimed to investigate the direct toxicity in cardiac fibroblast and endothelial cells of 35 FDA-approved anti-cancer drugs, of which the effects previously only had been explored in cardiomyocytes.

METHODS AND RESULTS

Metabolic cell viability in cardiac fibroblasts and endothelial cells was first determined using the CellTiter-Glo luminescence assay. If metabolic cell viability was reduced, lactate dehydrogenase was measured in the supernatant to assess cytotoxicity. Interestingly, certain anti-cancer treatments were able to increase metabolic cell viability. For these drugs, gene expression analysis assessing for myofibroblast differentiation and endothelial-to-mesenchymal transition was performed.

CONCLUSION

Our study demonstrates that anti-cancer therapies indeed exhibited different toxicity profiles in cardiac fibroblasts and endothelial cells compared to cardiomyocytes and triggers specific pathophysiological transformations in response to anti-cancer drug exposure.

GSTM1 suppresses cardiac fibrosis post-myocardial infarction through inhibiting lipid peroxidation and ferroptosis

BACKGROUND

Cardiac fibrosis following myocardial infarction (MI) drives adverse ventricular remodeling and heart failure, with cardiac fibroblasts (CFs) playing a central role. GSTM1 is an important member of the glutathione S-transferase (GSTs) family, which plays an important role in maintaining cell homeostasis and detoxification. This study investigated the role and mechanism of GSTM1 in post-MI fibrosis.

METHODS

Multi-omics approaches (proteomics/scRNA-seq) identified GSTM1 as a dysregulated target in post-MI fibroblasts. Using a murine coronary ligation model, we assessed GSTM1 dynamics via molecular profiling, such as Western blotting, immunofluorescence, and real-time quantitative polymerase chain reaction. AAV9-mediated cardiac-specific GSTM1 overexpression was achieved through systemic delivery. In vitro studies employed transforming growth factor-β (TGF-β)-stimulated primary fibroblasts with siRNA/plasmid interventions. Mechanistic insights were derived from transcriptomics and lipid peroxidation assays.

RESULTS

The expression of GSTM1 in mouse CFs after MI was significantly down-regulated at both transcriptional and protein levels. In human dilated cardiomyopathy (DCM) patients with severe heart failure, GSTM1 expression was decreased alongside aggravated fibrosis. Overexpression of GSTM1 in post-MI mice improved cardiac function, while significantly reducing infarct size and fibrosis compared with the control group. In vitro models demonstrated that GSTM1 markedly attenuated collagen secretion and activation of fibroblasts, as well as suppressed their proliferation and migration. Further studies revealed that GSTM1 overexpression significantly inhibited the generation of intracellular and mitochondrial reactive oxygen species (ROS) under pathological conditions, suggesting that GSTM1 exerts an antioxidative stress effect in post-infarction fibroblasts. Further investigation of molecular mechanisms indicated that GSTM1 may suppress the initiation and progression of fibrosis by modulating lipid metabolism and ferroptosis-related pathways. Overexpression of GSTM1 significantly reduced lipid peroxidation and free ferrous iron levels in fibroblasts and mitochondria, markedly decreased ferroptosis-related indicators, and alleviated oxidative lipid levels [such as 12-hydroxyeicosapentaenoic acid (HEPE) and 9-, 10-dihydroxy octadecenoic acid (DHOME)] under fibrotic conditions. GSTM1 enhanced the phosphorylation of STAT3, thereby upregulating the downstream expression of glutathione peroxidase 4 (GPX4), reducing ROS production, and mitigating fibroblast activation and phenotypic transformation by inhibiting lipid peroxidation.

CONCLUSIONS

This study identifies GSTM1 as a key inhibitor of fibroblast activation and cardiac fibrosis, highlighting its ability to target ferroptosis through redox regulation. AAV-mediated GSTM1 therapy demonstrates significant therapeutic potential for improving outcomes post-MI.

Autophagy in cardiac pathophysiology: Navigating the complex roles and therapeutic potential in cardiac fibrosis

Cardiac fibrosis is a critical factor in cardiac structural remodeling and dysfunction, closely associated with the progression of various cardiovascular diseases (CVDs), including heart failure and myocardial infarction (MI). It is characterized by excessive extracellular matrix (ECM) deposition, which disrupts normal cardiac architecture and impairs cardiac function. Autophagy, a cellular degradation and recycling mechanism, is essential for maintaining cardiac homeostasis, mitigating stress responses, and preventing cellular damage. Recent studies have revealed a significant link between autophagy and cardiac fibrosis, suggesting that autophagic dysregulation can exacerbate fibrosis by promoting fibroblast activation and ECM accumulation. Conversely, proper autophagic activity may attenuate cardiac fibrosis by removing damaged cellular components and regulating fibrotic signaling pathways. This review examines the role of autophagy in cardiac fibrosis. It also emphasizes potential pharmacological strategies that can be used to modulate autophagic processes. These strategies may serve as therapeutic approaches for treating cardiac fibrosis, with the ultimate goal of preventing excessive fibrosis and enhancing cardiac function.

Myocardial Fibrosis: Assessment, Quantification, Prognostic Signification, and Anti-Fibrosis Targets: A State-of-the-Art Review

Myocardial fibrosis (MF) is the excessive deposition of extracellular matrix (ECM) from myofibroblasts and is crucial in patients with heart failure (HF). Much work is still needed to fully understand its features and clinical role. This review aims to summarize the state-of-the-art of MF knowledge, focusing on assessment, quantification, predictive value, and future therapies. We performed a literature search about MF studies published between 2014 and 2024, including clinical studies on MF assessment or quantification, the role of MF as a prognostic factor in patients with HF, basic science studies on fibrosis assessment, and the role of the main mechanisms involved in MF. We identified 5161 potentially relevant articles. After excluding non-appropriate ones, we had 186 potentially suitable studies. After full reading and a review of references, 40 articles were included in our review: 8 were about MF assessment, 5 about quantification, and 27 about fibrosis as a prognostic factor. MF is a crucial process in patients with cardiac diseases and leads to HF and arrhythmias. Assessment and quantification have taken great steps forward, but more research is needed to strengthen MF's role as a prognostic factor in the future. Basic science will play a key role in anti-fibrosis treatment.

Network pharmacology and experimental validation to investigate the mechanism of action of Zhilong Huoxue Tongyu capsule in the prevention and treatment of diabetic cardiomyopathy

BACKGROUND

Diabetes cardiomyopathy (DCM) is a prevalent complication of diabetes, characterized by a multifaceted pathogenesis. Zhilong Huoxue Tongyu Capsule (ZL), a traditional Chinese medicine, is extensively employed for the treatment of cardiovascular diseases. Thus, this study aimed to comprehensively explore the mechanism of action of ZL on DCM.

METHOD

Network pharmacology approaches were applied to predict the potential pathways and targets of ZL on DCM. Then, a DCM model mouse was constructed and divided into a control group, DCM group, DCM + ZL group, SB203580 group, and DCM + R group. The DCM + ZL group was administered 6.24g/kg/d ZL via gavage, the SB203580 group was given 1 mg/kg/d SB203580 (p38MAPK inhibitor) via intraperitoneal injection, the DCM + R group received 4 mg/kg/d rosiglitazone via gavage, and the control group and DCM group were given equal volume of physiological saline by gavage. The intervention period lasted for 6 weeks to verify these key targets.

RESULT

Network pharmacology analyses identified 45 active ingredients in ZL linked to 719 potential targets, forming an herbal compound-target network. Screening of databases revealed 1032 DCM-related targets, with MAPK14, TNF, FOS, AKT1, and IL-10 emerging as key hub genes from PPI network analysis. Additionally, enrichment analysis indicated that the candidate targets were enriched in response to the MAPK signaling pathway. Finally, in vivo studies in DCM mice demonstrated that ZL significantly mitigated myocardial fibrosis and down-regulated the expression of p-P38MAPK, TNF-α, α-SMA, and Collagen-I proteins in myocardial tissue.

CONCLUSION

Our results collectively indicated that ZL can effectively ameliorate diabetes cardiomyopathy, possibly by modulating the P38MAPK signaling pathway.

AEBP1 or ACLP, which is the key factor in inflammation and fibrosis?

Adipocyte enhancer-binding protein 1 (AEBP1) and Aortic carboxypeptidase-like protein (ACLP) are two protein isoforms produced by the AEBP1 gene. AEBP1, originally discovered in preadipocytes, functions as a transcriptional repressor and is involved in promoting inflammation, proliferation, and migration through various signaling pathways. ACLP is an extracellular matrix protein linked to Ehlers-Danlos syndrome, a genetic disorder characterized by defective connective tissue development. Structurally, AEBP1 and ACLP share many similarities, and both participate in critical physiological or pathological processes, such as cancer and fibrosis, by influencing pathways like NK-κB, WNT, and TGF-β. In recent years, research on AEBP1 and ACLP has expanded to include major organs such as the brain, kidneys, and lungs, with a particular focus on the cardiovascular system, where they show potential as novel drug targets. However, most studies do not clearly distinguish between AEBP1 and ACLP. For instance, AEBP1 is implicated in myocardial fibrosis in hypertrophic cardiomyopathy models, whereas ACLP is associated with fibrosis in other organs. Additionally, literature on the relationship between AEBP1 and fibrosis is often contradictory. Clarifying the distinct roles of AEBP1 and ACLP and their different functions in various cell types would greatly benefit further research. Current research suggests that the AEBP1 gene encodes two proteins, AEBP1 and ACLP, which have been reported to exhibit distinct functions in different studies. However, many studies do not differentiate between these two proteins, potentially leading to misconceptions. Therefore, we have conducted a comprehensive review of the existing literature to elucidate the functions of the AEBP1 gene and its encoded proteins in detail.

YTHDF3-mediated FLCN/cPLA2 axis improves cardiac fibrosis via suppressing lysosomal function

Cardiac fibrosis characterized by aberrant activation of cardiac fibroblasts impairs cardiac contractile and diastolic functions, inducing the progression of the disease towards its terminal phase, resulting in the onset of heart failure. Therefore, the inhibition of cardiac fibrosis has become a promising treatment for cardiac diseases. The ovarian follicle-stimulating hormone folliculin (FLCN) plays a significant role in various biological processes, such as lysosome function, mitochondrial synthesis, angiogenesis, ciliogenesis and autophagy. Severe heart failure was observed in FLCN knockout mice. In this study, we investigated the role of FLCN in cardiac fibrosis and its potential mechanisms. The mice were subjected to transverse aortic constriction (TAC) surgery. Myocardial fibrosis developed in the mice 8 weeks after surgery. We showed that the protein and mRNA expression levels of FLCN were significantly decreased in TAC mice. Similar results were observed in primary mouse cardiac fibroblasts treated with Ang-II, an in vitro cardiac fibrosis model, suggesting that FLCN is involved in the pathological process of cardiac fibrosis. We demonstrated that overexpression of FLCN inhibited lysosome function in cardiac fibroblasts. Furthermore, overexpression of FLCN protected the heart from TAC-induced pathological cardiac fibrosis. We revealed that FLCN bound to the cPLA2 protein, increased its activity, regulated lysosomal function, and promoted membrane permeabilisation in cardiac fibroblasts during cardiac fibrosis. Knockdown of cPLA2 blocked the antifibrotic effect of FLCN in cardiac fibrosis. In addition, we found that the reduced expression of FLCN in cardiac fibrosis resulted from the modulation of YTHDF3-regulated m6A methylation of FLCN mRNA. The overexpression of YTHDF3 alleviated the production of collagens and improved cardiac structure and function in TAC mice. YTHDF3 inhibited proliferation and differentiation and regulated lysosomal function in mouse cardiac fibroblasts, whereas these effects were abolished by FLCN knockdown. We conclude that FLCN undergoes YTHDF3-regulated m6A modification and interacts with cPLA2 to improve lysosomal function in cardiac fibroblasts, highlighting its role in myocardial fibrosis therapy. These results suggest that FLCN and YTHDF3 could serve as potential therapeutic targets for cardiac fibroblast treatment.

Discovering genetically-supported drug targets for multisite chronic pain through multi-omics Mendelian randomization and single-cell RNA-sequencing

Multisite chronic pain (MCP) is a highly prevalent disorder with substantial unmet therapeutic needs.We conducted multi-omics Mendelian randomization and Bayesian colocalization to identify potential therapeutic targets for MCP. Summary-level data of gene expressions and protein abundance levels were obtained from corresponding quantitative trait loci studies, respectively. Summary-level data for MCP was leveraged from the UK Biobank. The transcriptome-wide association study (TWAS), Mendelian randomization, and Bayesian colocalization approaches were applied to investigate the potential causal effects of gene expressions and protein levels on MCP in both blood and brain tissues. Phenome-wide Mendelian randomization analysis (MR-PheWAS), single-cell sequencing data, protein-protein interaction (PPI), and reaction pathway analysis were further conducted to digging the underlying mechanisms. Our analysis identified and validated two plasma targets for MCP, namely KLC1 and LANCL1, at both gene expression levels and protein levels across multi-methodologies. Moreover, MR-PheWAS observed additional benefits associated with these two targets. Through analyses based on single-cell sequencing data, we identified critical cell types for KLC1, primarily megakaryocytes, and neurons, notably linked to the axon guidance pathway, while LANCL1 showed associations with B lymphocytes, neurons, and the electron transport pathway. In dorsal root ganglions, we identified enrichments of both LANCL1 and KLC1 in putative silent nociceptors. The effects are possibly mediated through axonal transport and the activation of NMDARs, supported by PPI and reaction pathway analysis. Our multi-dimensional analysis suggests that genetically determined KLC1 and LANCL1 are causally linked to MCP risk, holding promise as appealing drug targets for MCP.

Hesperidin improves cardiac fibrosis induced by β-adrenergic activation through modulation of gut microbiota

Cardiac fibrosis is a prevalent characteristic of various cardiovascular diseases and poses a significant global health challenge. Recent research has established a robust correlation between gut microbiota and cardiovascular diseases. Hesperidin has been shown to possess cardioprotective properties to some extent. Furthermore, studies suggest that hesperidin may enhance overall health by regulating intestinal flora. However, there is a lack of reports regarding the effects of hesperidin on cardiac fibrosis. This study aimed to investigate the mechanisms by which hesperidin ameliorates cardiac fibrosis through the regulation of gut microbiota and associated metabolites. Cardiac fibrosis was induced in C57BL/6 mice via subcutaneous injection of isoproterenol (5 mg/kg per day) for a duration of 7 days. Echocardiography was used to assess cardiac function, while Masson staining, western blot analysis, and real-time polymerase chain reaction were used to evaluate fibrosis-related indicators. Changes in gut microbiota were analyzed through 16S ribosomal RNA gene sequencing. Our findings indicate that hesperidin significantly mitigates cardiac fibrosis in mice. These beneficial effects are associated with improvements in the dysbiosis of intestinal microbiota observed in fibrotic mouse models. The involvement of gut microbiota in cardiac fibrosis was further corroborated by administering hesperidin therapy to mice depleted of gut microbiota. To our knowledge, this study provides the first evidence that the modulation of gut microbiota by hesperidin contributes to improved outcomes in cardiac fibrosis. The use of traditional Chinese medicine to modulate gut microbiota presents a promising strategy for the treatment of cardiac fibrosis. SIGNIFICANCE STATEMENT: The work is extremely interesting because it acts on a frontier of science that relates the influence of the intestinal microbiota with human physiological systems and associated pathologies. This study provides the first evidence that the modulation of gut microbiota by hesperidin contributes to improved outcomes in cardiac fibrosis.

Chrysophanol Attenuates Cardiac Fibrosis and Arrhythmia by Suppressing the Endoplasmic Reticulum Stress/Pyroptosis Axis and Inflammation

Chrysophanol (CHR), one of the principal bioactive compounds extracted from the rhizome of Rheum palmatum L., is known for its anti-inflammatory, antioxidative, anti-cancer, and cardioprotective effects. However, the effect of CHR on cardiac fibrosis remains elusive. In this study, mice were administered isoproterenol (ISO) to induce cardiac fibrosis in vivo, and cardiac fibroblasts were pretreated with transforming growth factor-β1 (TGF-β1) to induce the transformation of fibroblasts into myofibroblasts in vitro. Western blot and reverse transcription-quantitative polymerase chain reaction analyses were performed to evaluate the endoplasmic reticulum (ER) stress and pyroptosis. Immunohistochemistry staining and ELISA analyses were used to detect the inflammation level. In vivo electrophysiological studies were conducted to assess arrhythmia susceptibility. Our findings revealed that CHR treatment ameliorated cardiac dysfunction and fibrosis in ISO-challenged mice. Moreover, CHR reduced susceptibility to ventricular fibrillation by reducing ventricular electrical remodeling and increasing the expression of gap junction proteins and ion channels. Additionally, CHR inhibited the TGF-β1-stimulated transformation of cardiac fibroblasts into myofibroblasts in vitro. CHR inhibited ER stress, pyroptosis, and inflammation in vivo and in vitro. Furthermore, tunicamycin (TM)-induced activation of ER stress abolished the protective effects of CHR. CHR treatment attenuates cardiac fibrosis and arrhythmia by suppressing the ER stress/pyroptosis axis and inflammation.

Acacetin as a natural cardiovascular therapeutic: mechanisms and preclinical evidence

Globally, cardiovascular disease (CVD) has emerged as a leading cause of mortality and morbidity. As the world's population ages, CVD incidence is on the rise, and extensive attention has been drawn to optimizing the therapeutic regimens. Acacetin, a natural flavonoid derived from various plants, has been demonstrated to have a wide spectrum of pharmacological properties, such as antioxidant, anti-inflammatory, anti-bacterial, and anti-tumor activities, as well as protective effects on diverse tissues and organs. Recently, increasing numbers of studies (mostly preclinical) have indicated that acacetin has potential cardiovascular protective effects and might become a novel therapeutic strategy for CVDs. The importance of acacetin in CVD treatment necessitates a systematic and comprehensive review of its protective effects on the cardiovascular system and the underlying mechanisms involved. Here, we first provide an overview of some basic properties of acacetin. Subsequently, the protective effects of acacetin on multiple CVDs, like arrhythmias, cardiac ischemia/reperfusion injury, atherosclerosis, myocardial hypertrophy and fibrosis, drug-induced cardiotoxicity, diabetic cardiomyopathy, hypertension, and cardiac senescence, are discussed in detail. The underlying mechanisms by which acacetin exhibits cardiovascular protection appear to involve suppressing oxidative stress, reducing inflammation, preventing cardiomyocyte apoptosis and endothelial cell injury, as well as regulating mitochondrial autophagy and lipid metabolism. Meanwhile, several critical signaling pathways have also been found to mediate the protection of acacetin against CVDs, including phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K/Akt/mTOR), sirtuin 1/AMP-activated protein kinase/peroxisome proliferator-activated receptor-γ coactivator-1α (Sirt1/AMPK/PGC-1α), transforming growth factor-β1/small mothers against decapentaplegic 3 (TGF-β1/Smad3), protein kinase B/endothelial nitric oxide synthase (Akt/eNOS), and others. Finally, we highlight the existing problems associated with acacetin that need to be addressed, such as the requirement for clinical evidence and enhanced bioavailability, as well as its potential as a promising cardiovascular drug candidate.

Regulatory roles of PIWI-interacting RNAs in cardiovascular disease

Cardiovascular disease remains the number one cause of death worldwide. Across the spectrum of cardiovascular pathologies, all are accompanied by changes in gene expression profiles spanning a variety of cellular components of the myocardium. Alterations in gene expression are regulated by small noncoding RNAs (sncRNAs), with P-element-induced WImpy testis (PIWI)-interacting RNAs (piRNAs) being the most abundant of the sncRNAs in the human genome. Composed of 21-35 nucleotides in length with a protective methyl group at the 3' end, piRNAs complex with highly conserved RNA-binding proteins termed PIWI proteins to recruit enzymes used for histone, DNA, RNA, and protein modifications. Thus, specific piRNA expression patterns can be exploited for early clinical diagnosis of cardiovascular disease and the development of novel RNA therapeutics that may improve cardiac health outcomes. This review summarizes the latest progress made on understanding how piRNAs regulate cardiovascular health and disease progression, including a discussion of their potential in the development of biomarkers and therapeutics.

Research Progress on the Antifibrotic Activity of Traditional Chinese Medicine Polysaccharides

Fibrosis is a pathological process characterized by excessive extracellular matrix (ECM) deposition and proliferation fibrous tissue, a condition associated with various chronic diseases, such as liver cirrhosis, inflammation of the lungs, and myocarditis. Clinical treatment options for fibrotic diseases are currently limited and have poor efficacy. However, recent studies have increasingly demonstrated that polysaccharides exhibit significant antifibrotic activity by modulating cell proliferation and migration, inhibiting inflammation and oxidative stress associated fibrosis and regulating gut microbiota. This review provides an overview of recent advances in polysaccharide research for antifibrosis and offers new perspectives on the treatment of fibrotic diseases.

Myocardial infarction serum preconditioning bone marrow mesenchymal stem cell-derived exosomes enhance anti-fibrosis in rat myocardial infarction hearts

Mesenchymal stem cells (MSCs) have been shown to attenuate myocardial fibrosis after myocardial infarction by secreting various bioactive molecules that positively affect the failing heart. We hypothesized that serum factors play an active role in the activation of bone marrow MSCs after myocardial infarction and explored the effect of differential exocytosis on cardiac repair after infarct serum preconditioning by examining whether exosomes derived from MSCs have a positive effect on cardiac fibrosis. Bone marrow MSCs were pretreated by collecting rat myocardial infarction serum, followed by the collection of myocardial infarction serum exosomes (MIS-EXO). In vivo, intramyocardial injection of exosomes was performed 30 min after permanent ligation of the anterior descending branches of Sprague Dawley rats, and echocardiography was performed at different time intervals to evaluate cardiac function. Hearts were sampled 4 weeks later, and the degree of myocardial fibrosis and inflammatory response were evaluated using hematoxylin and eosin and Masson's trichrome staining. Treatment with common culture-derived exosomes (CON-EXO) improved cardiac function and myocardial fibrosis after myocardial infarction in rats compared with the myocardial infarction group. In vitro, the antifibrotic effects of different exosomes on tumor growth factor-β-induced fibroblast fibrosis model were assessed by protein blotting, qPCR, and immunofluorescence. Compared with CON-EXO, MIS-EXO exerted superior therapeutic effects in terms of anti-inflammation, improvement of left ventricular function, and reduction of fibrosis. Infarct serum pretreatment with bone marrow mesenchymal stem cell-derived exosomes enhances the anti-cardiac fibrosis effect in rats after myocardial infarction.

Decoding the regulatory roles of circular RNAs in cardiac fibrosis

Cardiovascular diseases (CVDs) are the primary cause of death globally. The evolution of nearly all types of CVDs is characterized by a common theme: the emergence of cardiac fibrosis. The precise mechanisms that trigger cardiac fibrosis are still not completely understood. In recent years, a type of non-coding regulatory RNA molecule known as circular RNAs (circRNAs) has been reported. These molecules are produced during back splicing and possess significant biological capabilities, such as regulating microRNA activity, serving as protein scaffolds and recruiters, competing with mRNA, forming circR-loop structures to modulate transcription, and translating polypeptides. Furthermore, circRNAs exhibit a substantial abundance, notable stability, and specificity of tissues, cells, and time, endowing them with the potential as biomarkers, therapeutic targets, and therapeutic agents. CircRNAs have garnered growing interest in the field of CVDs. Recent investigations into the involvement of circRNAs in cardiac fibrosis have yielded encouraging findings. This study aims to provide a concise overview of the existing knowledge about the regulatory roles of circRNAs in cardiac fibrosis.

Targeting cardiac fibrosis with Chimeric Antigen Receptor-Engineered Cells

Cardiac fibrosis poses a significant challenge in cardiovascular diseases due to its intricate pathogenesis, and there is currently no standardized and effective treatment approach. The fibrotic process entails the involvement of various cell types and molecular mechanisms, such as fibroblast activation and proliferation, increased collagen synthesis, and extracellular matrix rearrangement. Traditional therapies often fall short in efficacy or carry substantial side effects. However, recent studies have shown that Chimeric Antigen Receptor T (CAR-T) cells can selectively target and eliminate activated cardiac fibroblasts (CFs) in mice, leading to reduced cardiac fibrosis and improved myocardial tissue compliance. This breakthrough presents a new and promising avenue for treating cardiac fibrosis. Currently, CAR-T cell-based therapy for cardiac fibrosis is undergoing animal experimentation, indicating ample scope for enhancement. Future investigations could explore the application of CAR cell therapy in cardiac fibrosis treatment, including the potential of CAR-natural killer (CAR-NK) cells and CAR macrophages (CAR-M), offering novel insights and strategies for combating cardiac fibrosis.

Immunoengineered mitochondria for efficient therapy of acute organ injuries via modulation of inflammation and cell repair

Acute organ injuries represent a major public health concern, driven by inflammation and mitochondrial dysfunction, leading to cell damage and organ failure. In this study, we engineered neutrophil membrane-fused mitochondria (nMITO), which combine the injury-targeting and anti-inflammatory properties of neutrophil membrane proteins with the cell repairing function of mitochondria. nMITO effectively blocked inflammatory cascades and restored mitochondrial function, targeting both key mechanisms in acute organ injuries. In addition, nMITO selectively targeted damaged endothelial cells via β-integrins and were delivered to injured tissues through tunneling nanotubes, enhancing their regulatory effects on inflammation and cell damage. In mouse models of acute myocardial injury, liver injury, and pancreatitis, nMITO notably reduced inflammatory responses and repaired tissue damage. These findings suggest that nMITO is a promising therapeutic strategy for managing acute organ injuries.

PD-1 inhibition disrupts collagen homeostasis and aggravates cardiac dysfunction through endothelial-fibroblast crosstalk and EndMT

Introduction

Cardiac immune-related adverse events (irAEs) from PD-1-targeting immune check-point inhibitors (ICIs) are an increasing concern due to their high mortality rate. Collagen plays a crucial role in maintaining cardiac structure, elasticity, and signal transduction; however, the effects and mechanisms of PD-1 inhibitor on cardiac collagen remodeling remain poorly understood.

Methods

C57BL/6 mice were injected with anti-mouse PD-1 antibody to create a PD-1 inhibitor-treated model. Cardiac function was measured by echocardiography, and collagen distribution was analyzed with Masson's trichrome staining and Sirius Red staining. Single-nucleus RNA sequencing was performed to examine the effects of PD-1 inhibition on gene expression in cardiac fibroblasts (CFs) and endothelial cells (ECs). EC-CF crosstalk was assessed using co-culture experiments and ELISA. ChIP assay was performed to analyze the regulation of TCF12 on TGF-β1 promoter. Western blot, qRT-PCR, and immunofluorescence staining were used to detect the expression of TCF12, TGF-β1, and endothelial-to-mesenchymal transition (EndMT) markers. Reactive oxygen species (ROS) levels were evaluated by DHE staining, MDA content, and SOD activity assays.

Results

We report a newly discovered cardiotoxic effect of PD-1 inhibitor, which causes aberrant collagen distribution in the heart, marked by a decrease in interstitial collagen and an increase in perivascular collagen deposition. Mechanistically, PD-1 inhibitor does not directly affect CFs but instead impact them through EC-CF crosstalk. PD-1 inhibitor reduces TGF-β1 secretion in ECs by downregulating TCF12, which we identify as a transcriptional promoter of TGF-β1. This subsequently decreases CF activity, leading to reduced interstitial collagen deposition. Additionally, PD-1 inhibitor induces EndMT, increasing perivascular collagen deposition. The endothelial dysfunction induced by PD-1 inhibitor results from ROS accumulation in ECs. Inhibiting ROS with N-acetylcysteine (NAC) preserves normal collagen distribution and cardiac function in PD-1 inhibitor-treated mice by reversing TCF12 downregulation and EndMT in ECs.

Conclusion

Our results suggest that PD-1 inhibitor causes ROS accumulation in cardiac ECs, leading to imbalanced collagen distribution (decrease in interstitial collagen and increase in perivascular collagen) in the heart by modulating TCF12/TGF-β1-mediated EC-CF crosstalk and EndMT. NAC supplementation could be an effective clinical strategy to mitigate PD-1 inhibitor-induced imbalanced collagen distribution and cardiac dysfunction.

The Application and Molecular Mechanisms of Mitochondria-Targeted Antioxidants in Chemotherapy-Induced Cardiac Injury

Chemotherapeutic agents play a crucial role in cancer treatment. However, their use is often associated with significant adverse effects, particularly cardiotoxicity. Drugs such as anthracyclines (e.g., doxorubicin) and platinum-based agents (e.g., cisplatin) cause mitochondrial damage, which is one of the main mechanisms underlying cardiotoxicity. These drugs induce oxidative stress, leading to an increase in reactive oxygen species (ROS), which in turn damage the mitochondria in cardiomyocytes, resulting in impaired cardiac function and heart failure. Mitochondria-targeted antioxidants (MTAs) have emerged as a promising cardioprotective strategy, offering a potential solution. These agents efficiently scavenge ROS within the mitochondria, protecting cardiomyocytes from oxidative damage. Recent studies have shown that MTAs, such as elamipretide, SkQ1, CoQ10, and melatonin, significantly mitigate chemotherapy-induced cardiotoxicity. These antioxidants not only reduce oxidative damage but also help maintain mitochondrial structure and function, stabilize mitochondrial membrane potential, and prevent excessive opening of the mitochondrial permeability transition pore, thus preventing apoptosis and cardiac dysfunction. In this review, we integrate recent findings to elucidate the mechanisms of chemotherapy-induced cardiotoxicity and highlight the substantial therapeutic potential of MTAs in reducing chemotherapy-induced heart damage. These agents are expected to offer safer and more effective treatment options for cancer patients in clinical practice.

Variations in ECM Topography, Fiber Alignment, Mechanical Stiffness, and Cellular Composition Between Ventral and Dorsal Ligamentum Flavum Layers: Insights Into Hypertrophy Pathogenesis

Background

Previous studies have suggested that changes in the composition of the extracellular matrix (ECM) play a significant role in the development of ligamentum flavum hypertrophy (LFH) and the histological differences between the ventral and dorsal layers of the hypertrophied ligamentum flavum. Although LFH is associated with increased fibrosis in the dorsal layer, comprehensive research exploring the characteristics of the ECM and its mechanical properties in both regions is limited. Furthermore, the distribution of fibrosis-associated myofibroblasts within LFH remains poorly understood. This study aimed to bridge the existing knowledge gap concerning the intricate relationships between ECM characteristics, mechanical properties, and myofibroblast expression in LFH.

Methods

Histological staining, scanning electron microscopy, and atomic force microscopy were used to analyze the components, alignment, and mechanical properties of the ECM. Immunostaining and western blot analyses were performed to assess the distribution of myofibroblasts in LF tissues.

Results

There were notable differences between the dorsal and ventral layers of the hypertrophic ligamentum flavum. Specifically, the dorsal layer exhibited higher collagen content and disorganized fibrous alignment, resulting in reduced stiffness. Immunohistochemistry analysis revealed a significantly greater presence of α-smooth muscle actin (αSMA)-stained cells, a marker for myofibroblasts, in the dorsal layer.

Conclusions

This study offers comprehensive insights into LFH by elucidating the distinctive ECM characteristics, mechanical properties, and cellular composition disparities between the ventral and dorsal layers. These findings significantly enhance our understanding of the pathogenesis of LFH and may inform future research and therapeutic strategies.

Direct fibroblast reprogramming: an emerging strategy for treating organic fibrosis

Direct reprogramming has garnered considerable attention due to its capacity to directly convert differentiated cells into desired cells. Fibroblasts are frequently employed in reprogramming studies due to their abundance and accessibility. However, they are also the key drivers in the progression of fibrosis, a pathological condition characterized by excessive extracellular matrix deposition and tissue scarring. Furthermore, the initial stage of reprogramming typically involves deactivating fibrotic pathways. Hence, direct reprogramming offers a valuable method to regenerate target cells for tissue repair while simultaneously reducing fibrotic tendencies. Understanding the link between reprogramming and fibrosis could help develop effective strategies to treat damaged tissue with a potential risk of fibrosis. This review summarizes the advances in direct reprogramming and reveals their anti-fibrosis effects in various organs such as the heart, liver, and skin. Furthermore, we dissect the mechanisms of reprogramming influenced by fibrotic molecules including TGF-β signaling, mechanical signaling, inflammation signaling, epigenetic modifiers, and metabolic regulators. Innovative methods for fibroblast reprogramming like small molecules, CRISPRa, modified mRNA, and the challenges of cellular heterogeneity and senescence faced by in vivo direct reprogramming, are also discussed.

Efficacy of Colchicine in Reducing NT-proBNP, Caspase-1, TGF-β, and Galectin-3 Expression and Improving Echocardiography Parameters in Acute Myocardial Infarction: A Multi-Center, Randomized, Placebo-Controlled, Double-Blinded Clinical Trial

Background: Caspase-1 (reflects NOD-like receptor protein 3 inflammasome activity), transforming growth factor-β (TGF-β), and Galectin-3 play significant roles in post-AMI fibrosis and inflammation. Recently, colchicine was shown to dampen inflammation after AMI; however, its direct benefit remains controversial. Objectives: This study aimed to analyze the benefit of colchicine in reducing NT-proBNP, Caspase-1, TGF-β,and Galectin-3 expression and improving systolic-diastolic echocardiography parameters among AMI patients. Methods: A double-blinded, placebo-controlled, randomized, multicenter clinical trial was conducted at three hospitals in East Java, Indonesia: Dr. Saiful Anwar Hospital Malang, Dr. Soebandi Hospital Jember, and Dr. Iskak Hospital Tulungagung, between 1 June and 31 December 2023. A total of 161 eligible AMI subjects were randomly allocated 1:1 to colchicine (0.5 mg daily) or standard treatment for 30 days. Caspase-1, TGF-β, and Galectin-3 were tested on day 1 and day 5 by ELISA, while NT-proBNP was tested on days 5 and 30. Transthoracic echocardiography was also performed on day 5 and day 30. Results: By day 30, no significant improvements in systolic-diastolic echocardiography parameters had been shown in the colchicine group. However, colchicine reduced the level of NT-proBNP on day 30 more than placebo (ΔNT-proBNP: -73.74 ± 87.53 vs. -75.75 ± 12.44 pg/mL; p < 0.001). Moreover, colchicine lowered the level of Caspase-1 expression on day 5 and the levels of TGF-β and Galectin-3 expression on day 1. Conclusions: Colchicine can reduce NT-proBNP, Caspase-1, TGF-β, and Galectin-3 expression significantly among AMI patients. Colchicine administration was capable of reducing post-AMI inflammation, ventricular dysfunction, and heart failure but did not improve systolic-diastolic echocardiography parameters (ClinicalTrials.gov identifier: NCT06426537).

Spiny mice (Acomys) have evolved cellular features to support regenerative healing

Spiny mice (Acomys spp.) are warm-blooded (homeothermic) vertebrates whose ability to restore missing tissue through regenerative healing has coincided with the evolution of unique cellular and physiological adaptations across different tissue types. This review seeks to explore how these bizarre rodents deploy unique or altered injury response mechanisms to either enhance tissue repair or fully regenerate excised tissue compared to closely related, scar-forming mammals. First, we examine overall trends in healing Acomys tissues, including the cellular stress response, the ability to activate and maintain cell cycle progression, and the expression of certain features in reproductive adults that are normally associated with embryos. Second, we focus on specific cell types that exhibit precisely regulated proliferation to restore missing tissue. While Acomys utilize many of the same cell types involved in scar formation, these cells exhibit divergent activation profiles during regenerative healing. Considered together, current lines of evidence support sustained deployment of proregenerative pathways in conjunction with transient activation of fibrotic pathways to facilitate regeneration and improve tissue repair in Acomys.

Extracellular vesicle therapeutics for cardiac repair

Extracellular vesicles (EVs) are cell-secreted heterogeneous vesicles that play crucial roles in intercellular communication and disease pathogenesis. Due to their non-tumorigenicity, low immunogenicity, and therapeutic potential, EVs are increasingly used in cardiac repair as cell-free therapy. There exist multiple steps for the design of EV therapies, and each step offers many choices to tune EV properties. Factors such as EV source, cargo, loading methods, routes of administration, surface modification, and biomaterials are comprehensively considered to achieve specific goals. PubMed and Google Scholar were searched in this review, 89 articles related to EV-based cardiac therapy over the past five years (2019 Jan - 2023 Dec) were included, and their key steps in designing EV therapies were counted and analyzed. We aim to provide a comprehensive overview that can serve as a reference guide for researchers to design EV-based cardiac therapies.

A Cross-talk between Nanomedicines and Cardiac Complications: Comprehensive View

Background:

Cardiovascular Diseases (CVDs) are the leading cause of global morbidity and mortality, necessitating innovative approaches for both therapeutics and diagnostics. Nanoscience has emerged as a promising frontier in addressing the complexities of CVDs.

Objective:

This study aims to explorethe interaction of CVDs and Nanomedicine (NMs), focusing on applications in therapeutics and diagnostics.

Observations:

In the realm of therapeutics, nanosized drug delivery systems exhibit unique advantages, such as enhanced drug bioavailability, targeted delivery, and controlled release. NMs platform, including liposomes, nanoparticles, and carriers, allows the precise drug targeting to the affected cardiovascular tissues with minimum adverse effects and maximum therapeutic efficacy. Moreover, nanomaterial (NM) enables the integration of multifunctional components, such as therapeutic agents and target ligands, into a single system for comprehensive CVD management. Diagnostic fronts of NMs offer innovative solutions for early detection and monitoring of CVDs. Nanoparticles and nanosensors enable highly sensitive and specific detection of Cardiac biomarkers, providing valuable insights into a disease state, its progression, therapeutic outputs, etc. Further, nano-based technology via imaging modalities offers high high-resolution imaging, aiding in the vascularization of cardiovascular structures and abnormalities. Nanotechnology-based imaging modalities offer high-resolution imaging and aid in the visualization of cardiovascular structures and abnormalities.

Conclusion:

The cross-talk of CVDs and NMs holds tremendous potential for revolutionizing cardiovascular healthcare by providing targeted and efficient therapeutic interventions, as well as sensitive and early detection for the improvement of patient health if integrated with Artificial Intelligence (AI).

Epidermal stem cell derived exosomes-induced dedifferentiation of myofibroblasts inhibits scarring via the miR-203a-3p/PIK3CA axis

Hypertrophic scar (HS) is a common fibroproliferative disorders with no fully effective treatments. The conversion of fibroblasts to myofibroblasts is known to play a critical role in HS formation, making it essential to identify molecules that promote myofibroblast dedifferentiation and to elucidate their underlying mechanisms. In this study, we used comparative transcriptomics and single-cell sequencing to identify key molecules and pathways that mediate fibrosis and myofibroblast transdifferentiation. Epidermal stem cell-derived extracellular vesicles (EpiSC-EVs) were isolated via ultracentrifugation and filtration, followed by miRNA sequencing to identify miRNAs targeting key molecules. After in vitro and in vivo treatment with EpiSC-EVs, we assessed antifibrotic effects through scratch assays, collagen contraction assays, Western blotting, and immunofluorescence. Transcriptomic sequencing and rescue experiments were used to investigate the molecular mechanism by which miR-203a-3p in EpiSC-EVs induces myofibroblast dedifferentiation. Our results indicate that PIK3CA is overexpressed in HS tissues and positively correlates with fibrosis. EpiSC-EVs were absorbed by scar-derived fibroblasts, promoting dedifferentiation from myofibroblasts to quiescent fibroblasts. Mechanistically, miR-203a-3p in EpiSC-EVs plays an essential role in inhibiting PIK3CA expression and PI3K/AKT/mTOR pathway hyperactivation, thereby reducing scar formation. In vivo studies confirmed that EpiSC-EVs attenuate excessive scarring through the miR-203a-3p/PIK3CA axis, suggesting EpiSC-EVs as a promising therapeutic approach for HS.

Active ingredients of traditional Chinese medicine inhibit NOD-like receptor protein 3 inflammasome: a novel strategy for preventing and treating heart failure

Heart failure (HF) has emerged as a significant global public health challenge owing to its high rates of morbidity and mortality. Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome is regarded as a pivotal factor in the onset and progression of HF. Therefore, inhibiting the activation of the NLRP3 inflammasome may represent a promising therapeutic approach for preventing and treating HF. The active ingredients serve as the foundation for the therapeutic effects of traditional Chinese medicine (TCM). Recent research has revealed significant advantages of TCM active ingredients in inhibiting the activation of the NLRP3 inflammasome and enhancing cardiac structure and function in HF. The study aimed to explore the impact of NLRP3 inflammasome activation on the onset and progression of HF, and to review the current advancements in utilizing TCM active ingredients to inhibit the NLRP3 inflammasome for preventing and treating HF. This provides a novel perspective for the future development of precise intervention strategies targeting the NLRP3 inflammasome to prevent and treat HF.

VASN knockout induces myocardial fibrosis in mice by downregulating non-collagen fibers and promoting inflammation

Myocardial fibrosis (MF) is an important cause of heart failure and cardiac arrest. Vasorin knockout (VASN-/-) leads to pathological cardiac hypertrophy (PCH); however, it is not yet clear whether this PCH transitions to MF in mice. VASN-knockout mice showed typical pathological, imaging, and molecular features of MF upon hematoxylin and eosin staining, Masson staining, Sirius red staining, quantitative polymerase chain reaction (qPCR), immunohistochemistry-paraffin (IHC-P), and immunofluorescence analyses. RNA was extracted from mouse heart tissue, identified, and sequenced in vitro. Differential analysis of the genes showed that the extracellular matrix (ECM) genes (COL6A1, COL9A1, and FRAS1) had strong correlations while their expression levels were significantly reduced by qPCR, IHC-P, and Western blotting. The expression levels of the ECM genes were significantly reduced but those of the inflammatory factors (IL1β and IL6) were significantly upregulated in the heart tissues of VASN-knockout mice. These preliminary results reveal that VASN knockout induces MF by regulating the non-collagen fibers and inflammation.

Nerol attenuates doxorubicin-induced heart failure by inhibiting cardiomyocyte apoptosis in rats

BACKGROUND

As a broad-spectrum anti-tumour drug, the clinical application of DOX is often limited owing to its cardiotoxicity. Nerol is a naturally occurring compound with both anti-inflammatory and antioxidant properties. However, the ability of Nerol to improve DOX-induced heart failure and its underlying mechanisms remain unclear.

METHODS

Rat models of DOX-induced heart failure were established and rats were treated with various doses of Nerol. Apoptosis in cardiomyocytes was detected using TUNEL staining and the expression levels of apoptosis-related proteins were detected using western blotting and immunofluorescence. In addition, mitochondrial structure was observed using electron microscopy, mitochondrial membrane potential was detected using a JC-1 fluorescent probe, and superoxide dismutase were detected to comprehensively evaluate the regulatory effect of Nerol on mitochondrial function and oxidative stress.

RESULTS

Analysis showed that the number of apoptotic cardiomyocytes was significantly reduced after Nerol treatment, accompanied by the downregulation of Bax protein expression and upregulation of Bcl-2 protein expression, suggesting that Nerol may inhibit the apoptotic process of cardiomyocytes by regulating the balance of Bcl-2 family proteins. In addition, the mitochondrial function of Nerol-treated rats was protected, as indicated by the stability of the mitochondrial membrane potential, integrity of mitochondrial morphology. These changes suggest that Nerol may reduce the severity of heart failure by improving mitochondrial function.

CONCLUSIONS

Nerol plays a positive role in alleviating DOX-induced heart failure in rats, possibly by inhibiting cardiomyocyte apoptosis. These findings provide novel evidence and potential targets for developing new cardioprotective drugs.

A Vaccine Against Fibroblast Activation Protein Improves Murine Cardiac Fibrosis by Preventing the Accumulation of Myofibroblasts

BACKGROUND

Myofibroblasts are primary cells involved in chronic response-induced cardiac fibrosis. Fibroblast activation protein (FAP) is a relatively specific marker of activated myofibroblasts and a potential target molecule. This study aimed to clarify whether a vaccine targeting FAP could eliminate myofibroblasts in chronic cardiac stress model mice and reduce cardiac fibrosis.

METHODS

We coadministered a FAP peptide vaccine with a cytosine-phosphate-guanine (CpG) K3 oligonucleotide adjuvant to male C57/BL6J mice and confirmed an elevation in the anti-FAP antibody titer. After continuous angiotensin II and phenylephrine administration for 28 days, we evaluated the degree of cardiac fibrosis and the number of myofibroblasts in cardiac tissues.

RESULTS

We found that cardiac fibrosis was significantly decreased in the FAP-vaccinated mice compared with the angiotensin II and phenylephrine control mice (3.45±1.11% versus 8.62±4.79%; P=4.59×10-3) and that the accumulation of FAP-positive cells was also significantly decreased, as indicated by FAP immunohistochemical staining (4077±1746 versus 7327±1741 cells/mm2; FAP vaccine versus angiotensin II and phenylephrine control; P=6.67×10-3). No systemic or organ-specific inflammation due to antibody-dependent cell cytotoxicity induced by the FAP vaccine was observed. Although the transient activation of myofibroblasts has an important role in maintaining the structural robustness in the process of tissue repair, the FAP vaccine showed no adverse effects in myocardial infarction and skin injury models.

CONCLUSIONS

Our study demonstrates the FAP vaccine can be a therapeutic tool for cardiac fibrosis.

Targeting Fibrosis: From Molecular Mechanisms to Advanced Therapies

As the final stage of disease-related tissue injury and repair, fibrosis is characterized by excessive accumulation of the extracellular matrix. Unrestricted accumulation of stromal cells and matrix during fibrosis impairs the structure and function of organs, ultimately leading to organ failure. The major etiology of fibrosis is an injury caused by genetic heterogeneity, trauma, virus infection, alcohol, mechanical stimuli, and drug. Persistent abnormal activation of "quiescent" fibroblasts that interact with or do not interact with the immune system via complicated signaling cascades, in which parenchymal cells are also triggered, is identified as the main mechanism involved in the initiation and progression of fibrosis. Although the mechanisms of fibrosis are still largely unknown, multiple therapeutic strategies targeting identified molecular mechanisms have greatly attenuated fibrotic lesions in clinical trials. In this review, the organ-specific molecular mechanisms of fibrosis is systematically summarized, including cardiac fibrosis, hepatic fibrosis, renal fibrosis, and pulmonary fibrosis. Some important signaling pathways associated with fibrosis are also introduced. Finally, the current antifibrotic strategies based on therapeutic targets and clinical trials are discussed. A comprehensive interpretation of the current mechanisms and therapeutic strategies targeting fibrosis will provide the fundamental theoretical basis not only for fibrosis but also for the development of antifibrotic therapies.

Maintenance of Cardiac Microenvironmental Homeostasis: A Joint Battle of Multiple Cells

Various cells such as cardiomyocytes, fibroblasts and endothelial cells constitute integral components of cardiac tissue. The health and stability of cardiac ecosystem are ensured by the action of a certain type of cell and the intricate interactions between multiple cell types. The dysfunctional cells exert a profound impact on the development of cardiovascular diseases by involving in the pathological process. In this paper, we introduce the dynamic activity, cell surface markers as well as biological function of the various cells in the heart. Besides, we discuss the multiple signaling pathways involved in the cardiac injury including Hippo/YAP, TGF-β/Smads, PI3K/Akt, and MAPK signaling. The complexity of different cell types poses a great challenge to the disease treatment. By characterizing the roles of various cell types in cardiovascular diseases, we sought to discuss the potential strategies for preventing and treating cardiovascular diseases.

Gene Therapy for Inflammatory Cascade in Intrauterine Injury with Engineered Extracellular Vesicles Hybrid Snail Mucus-enhanced Adhesive Hydrogels

Early hyper-inflammation caused by intrauterine injury triggered subsequent intrauterine adhesion (IUA). STAT1-mediated M1 macrophages are confirmed to secrete pro-inflammatory cytokines to accelerate inflammatory cascade and IUA formation by multi-omics analysis and experimental verification. However, clinically used hyaluronic acid (HA) hydrogels are prone to slip out of injury sites due to poor bio-adhesion properties. Therefore, there are still challenges in applying hydrogels for M1 macrophage intervention in IUA treatment. Herein, an engineered extracellular vesicles (EVs) hybrid snail mucus (SM)-enhanced adhesive hydrogels to improve bio-adhesion property is fabricated and M1 macrophage intervention through targeting delivery and STAT1 silencing is achieved. First, inspired by the high bio-adhesion capacity of SM, SM and gelatin methacrylate (GelMA) solution are mixed to construct GelMA/SM (GS) hydrogel. Then, folic acid-modified extracellular vesicles (FA-EVs) are synthesized for targeting the delivery of STAT1-siRNA. Upon injection of FA-EVs hybrid GS hydrogel into the uterine cavity, a protective hydrogel layer forms on the surface of injury sites and sustains the release of STAT1-siRNA-loaded FA-EVs to curtail M1 macrophages generation through inhibiting STAT1 phosphorylation, resulting in reduction of myofibroblasts activation and collagen deposition. In addition, the pregnancy rate and the number of fetuses in rats treated with this hydrogel were much higher than those in other groups, suggesting that the hydrogel could promote functional endometrial regeneration and restore fertility. Overall, this study presents a promising strategy for employing FA-EVs hybrid adhesive hydrogel with superior bio-adhesion properties and M1 macrophage targeting delivery for IUA treatment and uterus recovery.

Trajectory of Cardiogenic Dementia: A New Perspective

The functions of the heart and brain are closely linked and essential to support human life by the heart-brain axis, which is a complex interconnection between the heart and brain. Also, cardiac function and cerebral blood flow regulate the brain's metabolism and function. Therefore, deterioration of cardiac function may affect cognitive function and may increase the risk of dementia. Cardiogenic dementia is defined as a cognitive deterioration due to heart diseases such as heart failure, myocardial infarction, and atrial fibrillation. The prevalence of cognitive impairment in patients with heart failure was 29%. In addition, coronary artery disease (CAD) is also associated with the development of cognitive impairment. CAD and reduction of myocardial contractility reduced cerebral blood flow and increased the risk of dementia in CAD patients. Furthermore, myocardial infarction and subsequent systemic haemodynamic instability promote the development and progression of cardiogenic dementia. These findings indicated that many cardiac diseases are implicated in the development and progression of cognitive impairment. Nevertheless, the underlying mechanism for the development of cardiogenic dementia was not fully elucidated. Consequently, this review aims to discuss the potential mechanisms involved in the pathogenesis of cardiogenic dementia.

Design, synthesis, and biological evaluation of novel 3-naphthylthiophene derivatives as potent SIRT2 inhibitors for the treatment of myocardial fibrosis

SIRT2 (sirtuin2) is a NAD+-dependent deacetylase implicated in fibrosis and inflammation of the liver, kidney, and heart. In this study, we designed and synthesized a series of 3-naphthylthiophene derivatives and evaluated their inhibitory activity against the SIRT2 enzyme. Among them, Z18 demonstrated outstanding SIRT2 inhibitory activity and selectivity. It significantly inhibited both the proliferation of cardiac fibroblasts (CFs) and the activity and expression of SIRT2 in CFs. Moreover, compound Z18 effectively suppressed TGF-β1-induced increases in α-SMA and CoL-1A1 protein expression, as well as hydroxyproline levels. Pharmacological mechanism tests demonstrated that Z18 inhibited SIRT2, thereby suppressing the TGF-β1-induced autocrine production of TGF-β1 and the phosphorylation of Smad2/3 in CFs. In MTT assays, Z18 exhibited a significant inhibitory effect on the proliferation of CFs induced by TGF-β1. In vivo, Z18 effectively ameliorated TAC- and ISO-induced declines in cardiac function, histopathological morphological changes, and collagen deposition. It also inhibited SIRT2 activity and reduced the expression of α-SMA and p-Smad2/3. In hepatorenal toxicity assays, Z18 exhibited an excellent safety profile. These results support the further development of the selective SIRT2 inhibitor Z18 as a potential lead compound for the treatment of myocardial fibrosis.

A Cross-talk between Nanomedicines and Cardiac Complications: Comprehensive View

BACKGROUND

Cardiovascular Diseases (CVDs) are the leading cause of global morbidity and mortality, necessitating innovative approaches for both therapeutics and diagnostics. Nanoscience has emerged as a promising frontier in addressing the complexities of CVDs.

OBJECTIVE

This study aims to explore the interaction of CVDs and Nanomedicine (NMs), focusing on applications in therapeutics and diagnostics.

OBSERVATIONS

In the realm of therapeutics, nanosized drug delivery systems exhibit unique advantages, such as enhanced drug bioavailability, targeted delivery, and controlled release. NMs platform, including liposomes, nanoparticles, and carriers, allows the precise drug targeting to the affected cardiovascular tissues with minimum adverse effects and maximum therapeutic efficacy. Moreover, Nanomaterial (NM) enables the integration of multifunctional components, such as therapeutic agents and target ligands, into a single system for comprehensive CVD management. Diagnostic fronts of NMs offer innovative solutions for early detection and monitoring of CVDs. Nanoparticles and nanosensors enable highly sensitive and specific detection of Cardiac biomarkers, providing valuable insights into a disease state, its progression, therapeutic outputs, etc. Further, nano-based technology via imaging modalities offers high high-resolution imaging, aiding in the vascularization of cardiovascular structures and abnormalities. Nanotechnology-based imaging modalities offer high-resolution imaging and aid in the visualization of cardiovascular structures and abnormalities.

CONCLUSION

The cross-talk of CVDs and NMs holds tremendous potential for revolutionizing cardiovascular healthcare by providing targeted and efficient therapeutic interventions, as well as sensitive and early detection for the improvement of patient health if integrated with Artificial Intelligence (AI).

Interleukin-38 ameliorates myocardial Ischemia-Reperfusion injury via inhibition of NLRP3 inflammasome activation in fibroblasts through the IL-1R8/SYK axis

OBJECTIVE

Although IL-38 is recognized for its regulatory role in a spectrum of chronic inflammatory diseases, investigations into its cardiac physiological and pathophysiological functions are nascent. Our aim was to delineate the biological impact of IL-38 in the context of myocardial ischemia-reperfusion injury (MIRI) and to uncover the mechanisms through which it exerts its effects.

METHODS AND RESULTS

In this study, we used an MIRI mouse model, LPS/ATP stimulation, and a hypoxia/reoxygenation cell model to determine the regulatory influence of IL-38 on MIRI. We observed that the administration of recombinant IL-38 to mice led to a reduction in infarct size, an enhancement in cardiac function, and a suppression of NLRP3 inflammasome activation. In contrast, genetic deletion of IL-38 was associated with an increase in infarct size, worsening of cardiac function, and upregulation of NLRP3 inflammasome activity. The detrimental effects associated with the absence of IL-38 were mitigated by the administration of a specific NLRP3 inhibitor, suggesting that the inhibition of NLRP3 is a critical component of the protective effect mediated by IL-38 in MIRI. In vitro assays revealed that IL-38 inhibited NLRP3 inflammasome activation in cardiac fibroblasts through the engagement of IL-1R8 and the modulation of SYK phosphorylation. Silencing of IL-1R8 negated the suppressive effect of IL-38 on the NLRP3 inflammasome.

CONCLUSION

IL-38 acts as a potent negative regulator of inflammasome activation after MIRI. It achieves this regulatory effect within cardiac fibroblasts by inhibiting SYK phosphorylation, a process mediated by IL-1R8.

Relaxin Inhibits Angiotensin II-Induced Cardiac Fibrosis by Activating NO/cGMP Signaling Pathway

BACKGROUND

Cardiac fibrosis, a key contributor to heart failure, is driven by the activation of cardiac fibroblasts (CFs), often induced by angiotensin II (Ang II). Relaxin, a peptide hormone, has been reported to counteract fibrotic processes. This study aims to investigate the antifibrotic effects of relaxin on Ang II-induced CF activation, with a focus on the involvement of the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling pathway.

METHODS

Primary CFs were isolated and treated with Ang II to induce fibrotic activation. Relaxin was used to assess its antifibrotic effects. Inhibitors of the NO/cGMP pathway, NG-nitro-L-arginine methyl ester (L-NAME) (a nitric oxide synthase inhibitor) and 1H-(1 ,2,4) -Oxadiazolo-(4, 3-a) quinoxalin-1-one (ODQ) (a guanylyl cyclase inhibitor), were co-administered to examine their effects on relaxin-mediated inhibition. Proliferation and migration were assessed using 5-Ethynyl-2'-de oxyur idine incorporation and Transwell assays. Western blot analysis was conducted to measure the expression of alpha-smooth muscle actin (α-SMA), collagen I, and collagen III, key markers of fibroblast activation. Nitric oxide, cGMP, total nitric oxide synthase (TNOS), and inducible nitric oxide synthase (iNOS) levels were measured in the culture media.

RESULTS

Ang II significantly increased CF proliferation, migration, and the expression of fibrosis markers α-SMA, collagen I, and collagen III. Relaxin treatment markedly reduced these effects. Inhibition of the NO/cGMP pathway by L-NAME or ODQ partially reversed relaxin's suppressive effects on CF proliferation and migration. Relaxin restored Ang II-induced reductions in NO, cGMP, and TNOS levels, while iNOS levels remained largely unchanged, except for a reduction in the L-NAME group.

CONCLUSION

Relaxin attenuates Ang II-induced cardiac fibroblast activation and fibrosis primarily through the NO/cGMP signaling pathway.

Transcriptome-wide RNA 5-methylcytosine profiles of human iPSCs and iPSC-derived cardiomyocytes

Cardiac regenerative therapy has recently progressed by reprogramming somatic cells into induced pluripotent stem cells (iPSCs) and advanced by large-scale differentiation-derived cardiomyocytes (hiPSC-CMs). However, repairing damaged cardiac tissues with hiPSC-CMs remains limited due to immune rejection, cardiac arrhythmias, and concerns over tumor formation after hiPSC-CM transplantation. Despite efforts in profiling epigenomic changes during cardiac differentiation, regulatory mechanisms underlying 5-methylcytosine (m5C) deposition in RNA m5C epitranscriptomic landscape during hiPSC-to-cardiomyocyte differentiation remain unclear. Herein, bisulfite RNA-sequencing analysis was conducted in human pluripotent stem cells (hPSCs) from three independent cellular origins, and their derived cardiomyocytes (hPSC-CM), metabolic-maturation of derived cardiomyocytes (hPSC-CM-lac) and biochemical-enhanced derived cardiomyocytes (hPSC-CM-TDI). Integrated analysis of differentially methylated RNA m5C profiles and transcriptome-wide expression facilitated the identification of m5C sites coupled to the cardiomyocyte differentiation and RNA-dependent regulatory mechanisms of stem cell pluripotency. The RNA m5C profiles in this dataset allow the evaluations of the m5C level and distribution of specific m5C loci and facilitate understanding of the m5C epitranscriptomic landscape in biological functions of hPSC-CM beyond in vivo transplantation barriers.

Multiscale drug screening for cardiac fibrosis identifies MD2 as a therapeutic target

Cardiac fibrosis impairs cardiac function, but no effective clinical therapies exist. To address this unmet need, we employed a high-throughput screening for antifibrotic compounds using human induced pluripotent stem cell (iPSC)-derived cardiac fibroblasts (CFs). Counter-screening of the initial candidates using iPSC-derived cardiomyocytes and iPSC-derived endothelial cells excluded hits with cardiotoxicity. This screening process identified artesunate as the lead compound. Following profibrotic stimuli, artesunate inhibited proliferation, migration, and contraction in human primary CFs, reduced collagen deposition, and improved contractile function in 3D-engineered heart tissues. Artesunate also attenuated cardiac fibrosis and improved cardiac function in heart failure mouse models. Mechanistically, artesunate targeted myeloid differentiation factor 2 (MD2) and inhibited MD2/Toll-like receptor 4 (TLR4) signaling pathway, alleviating fibrotic gene expression in CFs. Our study leverages multiscale drug screening that integrates a human iPSC platform, tissue engineering, animal models, in silico simulations, and multiomics to identify MD2 as a therapeutic target for cardiac fibrosis.

Exogenous H2S targeting PI3K/AKT/mTOR pathway alleviates chronic intermittent hypoxia-induced myocardial damage through inhibiting oxidative stress and enhancing autophagy

AIMS

Hydrogen sulfide (H2S) is a novel gas signaling molecule that has been researched in several physiological and pathological conditions, indicating that strategies targeting H2S may provide clinical benefits in diseases such as chronic cardiomyopathy. Here, we reveal the effect of H2S on chronic intermittent hypoxia (CIH)-related myocardial damage and its mechanistic relevance to phosphoinositol-3 kinase (PI3K).

MATERIALS

Mice were subjected to a 4-week CIH process to induce myocardial damage, which was accompanied by daily administration of NaHS (a H2S donor) and LY294002 (an inhibitor of PI3K). Changes in heart function were evaluated via echocardiography. Histological examination was applied to assess heart tissue lesions. Myocardial apoptosis was detected by TUNEL staining and apoptosis-associated protein expression. Furthermore, the effects of NaHS on autophagy and the PI3K/AKT/mTOR pathway were investigated. Finally, the level of inflammation is also affected by related proteins.

KEY FINDINGS

The CIH group presented increased myocardial dysfunction and heart tissue lesions. Echocardiography and histological analysis revealed that, compared with control mice, CIH-treated mice presented significantly more severe left ventricular remodeling and decreased myocardial contractile function. In addition, the apoptosis index and oxidative markers were significantly elevated in the CIH group compared with those in the control group. The autophagy marker Beclin-1 was decreased, while p62 was elevated by CIH treatment. H2S supplementation with NaHS significantly improved cardiac function and alleviated fibrosis, oxidative stress, and apoptosis but upregulated autophagy in CIH mice, and these effects were also observed in animals that underwent only PI3K blockade. Furthermore, PI3K/AKT pathway-mediated inhibition of the mammalian target of rapamycin (mTOR) pathway, the Nrf2/HO-1 pathway and proinflammatory NF-κB activity were shown to play a role in the therapeutic effect of NaHS after CIH stimulation.

Myocardial fibrosis from the perspective of the extracellular matrix: Mechanisms to clinical impact

Fibrosis is defined by the excessive accumulation of extracellular matrix (ECM) and constitutes a central pathophysiological process that underlies tissue dysfunction, across organs, in multiple chronic diseases and during aging. Myocardial fibrosis is a key contributor to dysfunction and failure in numerous diseases of the heart and is a strong predictor of poor clinical outcome and mortality. The excess structural and matricellular ECM proteins deposited by cardiac fibroblasts, is found between cardiomyocytes (interstitial fibrosis), in focal areas where cardiomyocytes have died (replacement fibrosis), and around vessels (perivascular fibrosis). Although myocardial fibrosis has important clinical prognostic value, access to cardiac tissue biopsies for histological evaluation is limited. Despite challenges with sensitivity and specificity, cardiac magnetic resonance imaging (CMR) is the most applicable diagnostic tool in the clinic, and the scientific community is currently actively searching for blood biomarkers reflecting myocardial fibrosis, to complement the imaging techniques. The lack of mechanistic insights into specific pro- and anti-fibrotic molecular pathways has hampered the development of effective treatments to prevent or reverse myocardial fibrosis. Development and implementation of anti-fibrotic therapies is expected to improve patient outcomes and is an urgent medical need. Here, we discuss the importance of the ECM in the heart, the central role of fibrosis in heart disease, and mechanistic pathways likely to impact clinical practice with regards to diagnostics of myocardial fibrosis, risk stratification of patients, and anti-fibrotic therapy.

Advances in the study of exosomes in cardiovascular diseases

BACKGROUND

Cardiovascular disease (CVD) has been the leading cause of death worldwide for many years. In recent years, exosomes have gained extensive attention in the cardiovascular system due to their excellent biocompatibility. Studies have extensively researched miRNAs in exosomes and found that they play critical roles in various physiological and pathological processes in the cardiovascular system. These processes include promoting or inhibiting inflammatory responses, promoting angiogenesis, participating in cell proliferation and migration, and promoting pathological progression such as fibrosis.

AIM OF REVIEW

This systematic review examines the role of exosomes in various cardiovascular diseases such as atherosclerosis, myocardial infarction, ischemia-reperfusion injury, heart failure and cardiomyopathy. It also presents the latest treatment and prevention methods utilizing exosomes. The study aims to provide new insights and approaches for preventing and treating cardiovascular diseases by exploring the relationship between exosomes and these conditions. Furthermore, the review emphasizes the potential clinical use of exosomes as biomarkers for diagnosing cardiovascular diseases.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Exosomes are nanoscale vesicles surrounded by lipid bilayers that are secreted by most cells in the body. They are heterogeneous, varying in size and composition, with a diameter typically ranging from 40 to 160 nm. Exosomes serve as a means of information communication between cells, carrying various biologically active substances, including lipids, proteins, and small RNAs such as miRNAs and lncRNAs. As a result, they participate in both physiological and pathological processes within the body.

Profiling of collagen and extracellular matrix deposition from cell culture using in vitro ExtraCellular matrix mass spectrometry imaging (ivECM-MSI)

While numerous approaches have been reported towards understanding single cell regulation, there is limited understanding of single cell production of extracellular matrix phenotypes. Collagens are major proteins of the extracellular microenvironment extensively used in basic cell culture, tissue engineering, and biomedical applications. However, identifying compositional regulation of collagen remains challenging. Here, we report the development of In vitro ExtraCellular Matrix Mass Spectrometry Imaging (ivECM-MSI) as a tool to rapidly and simultaneously define collagen subtypes from coatings and basic cell culture applications. The tool uses the mass spectrometry imaging platform with reference libraries to produce visual and numerical data types. The method is highly integrated with basic in vitro strategies as it may be used with conventional cell chambers on minimal numbers of cells and with minimal changes to biological experiments. Applications tested include semi-quantitation of collagen composition in culture coatings, time course collagen deposition, deposition altered by gene knockout, and changes induced by drug treatment. This approach provides new access to proteomic information on how cell types respond to and change the extracellular microenvironment and provides a holistic understanding of both the cell and extracellular response.

Circ_0079480 facilitates proliferation, migration and fibrosis of atrial fibroblasts in atrial fibrillation by sponing miR-338-3p to activate the THBS1/TGF-β1/Smad3 signaling

BACKGROUND

Atrial fibrosis is associated with the pathogenesis of atrial fibrillation (AF). This study aims to discuss the function of circ_0079480 in atrial fibrosis and its underlying mechanism.

METHODS

In vitro and in vivo models of atrial fibrosis were established by using angiotensin II (Ang II) to treat human atrial fibroblasts (HAFs) and C57/B6J mice. qRT-PCR and western blot were used to examine the mRNA and protein expression levels. CCK-8, EdU, cell strach, and transwell assays were performed to determine the proliferation and migration of HAFs. Dual-luciferase reporter and RIP/RNA pull-down assays were explored to identify the interaction of miR-338-3p and circ_0079480/THBS1. HE and Masson's trichrome staining experiments were performed to analyze the histopathological change in mice atrial tissues.

RESULTS

Circ_0079480 expression was increased in AF patients' atrial tissues and Ang II-treated HAFs. Silencing circ_0079480 inhibited cell proliferation and migration and reduced fibrosis-associated gene expression in Ang II-treated HAFs. Circ_0079480 could target miR-338-3p to repress its expression. MiR-338-3p inhibitor blocked the inhibitory effects of circ_0079480 knockdown on HAFs proliferation, migration, and fibrosis. Thrombospondin-1 (THBS1) was confirmed as a downstream target of miR-338-3p, and circ_0079480 could sponge miR-338-3p to upregulate THBS1 expression. Moreover, silencing THBS1 suppressed Ang II-induced proliferation, migration, and fibrosis in HAFs. More importantly, depletion of circ_0079480 inactivated the THBS1/TGF-β1/Smad3 signaling by upregulating miR-338-3p. Mice experiments also confirmed the suppression of circ_0079480 knockdown on atrial fibrosis.

CONCLUSION

Circ_0079480 acts as a sponge of miR-338-3p to upregulate THBS1 expression and activate the TGF-β1/Smad3 signaling, finally promoting Ang II-induced atrial fibrosis.