Exosomes from Bone Marrow Mesenchymal Stem Cells with Overexpressed Nrf2 Inhibit Cardiac Fibrosis in Rats with Atrial Fibrillation

Hypoxic extracellular vesicles from hiPSCs protect cardiomyocytes from oxidative damage by transferring antioxidant proteins and enhancing Akt/Erk/NRF2 signaling

BACKGROUND

Stem cell-derived extracellular vesicles (EVs) are an emerging class of therapeutics with excellent biocompatibility, bioactivity and pro-regenerative capacity. One of the potential targets for EV-based medicines are cardiovascular diseases (CVD). In this work we used EVs derived from human induced pluripotent stem cells (hiPSCs; hiPS-EVs) cultured under different oxygen concentrations (21, 5 and 3% O2) to dissect the molecular mechanisms responsible for cardioprotection.

METHODS

EVs were isolated by ultrafiltration combined with size exclusion chromatography (UF + SEC), followed by characterization by nanoparticle tracking analysis, atomic force microscopy (AFM) and Western blot methods. Liquid chromatography and tandem mass spectrometry coupled with bioinformatic analyses were used to identify differentially enriched proteins in various oxygen conditions. We directly compared the cardioprotective effects of these EVs in an oxygen-glucose deprivation/reoxygenation (OGD/R) model of cardiomyocyte (CM) injury. Using advanced molecular biology, fluorescence microscopy, atomic force spectroscopy and bioinformatics techniques, we investigated intracellular signaling pathways involved in the regulation of cell survival, apoptosis and antioxidant response. The direct effect of EVs on NRF2-regulated signaling was evaluated in CMs following NRF2 inhibition with ML385.

RESULTS

We demonstrate that hiPS-EVs derived from physiological hypoxia at 5% O2 (EV-H5) exert enhanced cytoprotective function towards damaged CMs compared to EVs derived from other tested oxygen conditions (normoxia; EV-N and hypoxia 3% O2; EV-H3). This resulted from higher phosphorylation rates of Akt kinase in the recipient cells after transfer, modulation of AMPK activity and reduced apoptosis. Furthermore, we provide direct evidence for improved calcium signaling and sustained contractility in CMs treated with EV-H5 using AFM measurements. Mechanistically, our mass spectrometry and bioinformatics analyses revealed differentially enriched proteins in EV-H5 associated with the antioxidant pathway regulated by NRF2. In this regard, EV-H5 increased the nuclear translocation of NRF2 protein and enhanced its transcription in CMs upon OGD/R. In contrast, inhibition of NRF2 with ML385 abolished the protective effect of EVs on CMs.

CONCLUSIONS

In this work, we demonstrate a superior cardioprotective function of EV-H5 compared to EV-N and EV-H3. Such EVs were most effective in restoring redox balance in stressed CMs, preserving their contractile function and preventing cell death. Our data support the potential use of hiPS-EVs derived from physiological hypoxia, as cell-free therapeutics with regenerative properties for the treatment of cardiac diseases.

The role and mechanism of heme oxygenase-1 in arrhythmias

The global incidence and prevalence of arrhythmias are continuously increasing. However, the precise mechanisms of underlying arrhythmogenesis and the optimal measures for effective treatment remain incompletely understood. The inducible form of heme oxygenase, known as heme oxygenase-1 (HO-1), is recognized as a potent antioxidant molecule capable of exerting anti-inflammatory and anti-apoptotic effects. Recent research indicates that HO-1 plays a role in preventing arrhythmias by mitigating cardiac remodeling, including electrical remodeling, ion remodeling, and structural remodeling. This review aimed to consolidate current knowledge regarding the involvement of HO-1 in arrhythmias and elucidate its underlying mechanisms of action.

Amplification of Cardioprotective Response of Remote Ischemic Preconditioning in Rats by Quercetin: Potential Role of Activation of mTOR-dependent Autophagy and Nrf2

OBJECTIVES

Noninvasive remote ischemic preconditioning (RIPC) is a practical, acceptable, and feasible conditioning technique reported to provide cardioprotection in myocardial ischemia-reperfusion injury (MIRI). It has been well-reported that quercetin possesses antioxidant and anti-inflammatory properties. This study investigates the modification of the cardioprotective response of RIPC by quercetin.

METHODS

Adult Wistar rats were randomized into 12 groups of six animals each. MIRI was induced by subjecting the isolated hearts of Wistar rats to global ischemia for 30 min, succeeded by reperfusion of 120 min after mounting on the Langendorff PowerLab apparatus. Hind limb RIPC was applied in four alternate cycles of ischemia and reperfusion of 5 min each by tying the pressure cuff before isolation of hearts.

RESULTS

MIRI was reflected by significantly increased infarct size, LDH-1, and CK-MB, TNF-α, TBARS, and decreased GSH, catalase, and hemodynamic index, and modulated Nrf2. Pretreatment of quercetin (25 and 50 mg/kg; i.p.) significantly attenuated the MIRI-induced cardiac damage and potentiated the cardioprotective response of RIPC at the low dose. Pretreatment of ketamine (10 mg/kg; i.p.), an mTOR-dependent autophagy inhibitor, significantly abolished the cardioprotective effects of quercetin and RIPC.

CONCLUSIONS

The findings highlight the modification of the cardioprotective effect of RIPC by quercetin and that quercetin protects the heart against MIRI through multiple mechanisms, including mTOR-dependent activation of autophagy and Nrf-2 activation.

Regulation of the Nrf2/HO-1 axis by mesenchymal stem cells-derived extracellular vesicles: implications for disease treatment

This comprehensive review inspects the therapeutic potential of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) across multiple organ systems. Examining their impact on the integumentary, respiratory, cardiovascular, urinary, and skeletal systems, the study highlights the versatility of MSC-EVs in addressing diverse medical conditions. Key pathways, such as Nrf2/HO-1, consistently emerge as central mediators of their antioxidative and anti-inflammatory effects. From expediting diabetic wound healing to mitigating oxidative stress-induced skin injuries, alleviating acute lung injuries, and even offering solutions for conditions like myocardial infarction and renal ischemia-reperfusion injury, MSC-EVs demonstrate promising therapeutic efficacy. Their adaptability to different administration routes and identifying specific factors opens avenues for innovative regenerative strategies. This review positions MSC-EVs as promising candidates for future clinical applications, providing a comprehensive overview of their potential impact on regenerative medicine.

Neferine mitigates angiotensin II-induced atrial fibrillation and fibrosis via upregulation of Nrf2/HO-1 and inhibition of TGF-β/p-Smad2/3 pathways

BACKGROUND

Atrial fibrillation (AF) is often associated with atrial fibrosis and oxidative stress. Neferine, a bisbenzylisoquinoline alkaloid, has been reported to exert an antiarrhythmic effect. However, its impact on Angiotensin II (Ang II) infusion-induced AF and the underlying mechanism remains unclear. This study aimed to investigate whether neferine alleviates Ang II-induced AF and explore the underlying mechanisms.

METHODS

Mice subjected to Ang II infusion to induce AF were concurrently treated with neferine or saline. AF incidence, myocardial cell size, fibrosis, and oxidative stress were then examined.

RESULTS

Neferine treatment inhibited Ang II-induced AF, atrial size augmentation, and atrial fibrosis. Additionally, we observed that Ang II increased reactive oxygen species (ROS) generation, induced mitochondrial membrane potential depolarization, and reduced glutathione (GSH) and superoxide dismutase (SOD) levels, which were reversed to some extent by neferine. Mechanistically, neferine activated the Nrf2/HO-1 signaling pathway and inhibited TGF-β/p-Smad2/3 in Ang II-infused atria. Zinc Protoporphyrin (ZnPP), an HO-1 inhibitor, reduced the anti-oxidative effect of neferine to some extent and subsequently abolished the beneficial effect of neferine on Ang II-induced AF.

CONCLUSIONS

These findings provide hitherto undocumented evidence that the protective role of neferine in Ang II-induced AF is dependent on HO-1.

BMSC-derived Exosomes Ameliorate Peritoneal Dialysis-associated Peritoneal Fibrosis via the Mir-27a-3p/TP53 Pathway

OBJECTIVE

Peritoneal fibrosis (PF) is the main cause of declining efficiency and ultrafiltration failure of the peritoneum, which restricts the long-term application of peritoneal dialysis (PD). This study aimed to investigate the therapeutic effects and mechanisms of bone marrow mesenchymal stem cells-derived exosomes (BMSC-Exos) on PF in response to PD.

METHODS

Small RNA sequencing analysis of BMSC-Exos was performed by second-generation sequencing. C57BL/6J mice were infused with 4.25% glucose-based peritoneal dialysis fluid (PDF) for 6 consecutive weeks to establish a PF model. A total of 36 mice were randomly divided into 6 groups: control group, 1.5% PDF group, 2.5% PDF group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to measure the expression level of miR-27a-3p in BMSC-Exos and peritoneum of mice treated with different concentrations of PDF. HE and Masson staining were performed to evaluate the extent of PF. The therapeutic potential of BMSC-Exos for PF was examined through pathological examination, RT-qPCR, Western blotting, and peritoneal function analyses. Epithelial-mesenchymal transition (EMT) of HMrSV5 was induced with 4.25% PDF. Cells were divided into control group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Cell Counting Kit-8 assay was used to measure cell viability, and transwell migration assay was used to verify the capacity of BMSC-Exos to inhibit EMT in HMrSV5 cells.

RESULTS

Small RNA sequencing analysis showed that miR-27a-3p was highly expressed in BMSC-derived exosomes compared to BMSCs. The RT-qPCR results showed that the expression of miR-27a-3p was upregulated in BMSC-Exos, but decreased in PD mice. We found that PF was glucose concentration-dependently enhanced in the peritoneum of the PD mice. Compared with the control mice, the PD mice showed high solute transport and decreased ultrafiltration volume as well as an obvious fibroproliferative response, with markedly increased peritoneal thickness and higher expression of α-SMA, collagen-I, fibronectin, and ECM1. The mice with PD showed decreased miR-27a-3p. Peritoneal structural and functional damage was significantly attenuated after BMSC-Exos treatment, while PF and mesothelial damage were significantly ameliorated. Additionally, markers of fibrosis (α-SMA, collagen-I, fibronectin, ECM1) and profibrotic cytokines (TGF-β1, PDGF) were downregulated at the mRNA and protein levels after BMSC-Exos treatment. In HMrSV5 cells, BMSC-Exos reversed the decrease in cell viability and the increase in cell migratory capacity caused by high-glucose PDF. Western blotting and RT-qPCR analysis revealed that BMSC-Exos treatment resulted in increased expression of E-cadherin (epithelial marker) and decreased expression of α-SMA, Snail, and vimentin (mesenchymal markers) compared to those of the 4.25% PDF-treated cells. Importantly, a dual-luciferase reporter assay showed that TP53 was a target gene of miR-27a-3p. TP53 overexpression significantly reversed the decreases in PF and EMT progression induced by BMSC-Exos.

CONCLUSION

The present results demonstrate that BMSC-Exos showed an obvious protective effect on PD-related PF and suggest that BMSC-derived exosomal miR-27a-3p may exert its inhibitory effect on PF and EMT progression by targeting TP53.

Unraveling the Signaling Dynamics of Small Extracellular Vesicles in Cardiac Diseases

Effective intercellular communication is essential for cellular and tissue balance maintenance and response to challenges. Cellular communication methods involve direct cell contact or the release of biological molecules to cover short and long distances. However, a recent discovery in this communication network is the involvement of extracellular vesicles that host biological contents such as proteins, nucleic acids, and lipids, influencing neighboring cells. These extracellular vesicles are found in body fluids; thus, they are considered as potential disease biomarkers. Cardiovascular diseases are significant contributors to global morbidity and mortality, encompassing conditions such as ischemic heart disease, cardiomyopathies, electrical heart diseases, and heart failure. Recent studies reveal the release of extracellular vesicles by cardiovascular cells, influencing normal cardiac function and structure. However, under pathological conditions, extracellular vesicles composition changes, contributing to the development of cardiovascular diseases. Investigating the loading of molecular cargo in these extracellular vesicles is essential for understanding their role in disease development. This review consolidates the latest insights into the role of extracellular vesicles in diagnosis and prognosis of cardiovascular diseases, exploring the potential applications of extracellular vesicles in personalized therapies, shedding light on the evolving landscape of cardiovascular medicine.

HACE1 expression in heart failure patients might promote mitochondrial oxidative stress and ferroptosis by targeting NRF2

BACKGROUND

Heart failure is a prevalent and life-threatening medical condition characterized by abnormal atrial electrical activity, contributing to a higher risk of ischemic stroke. Atrial remodelling, driven by oxidative stress and structural changes, plays a central role in heart failure progression. Recent studies suggest that HACE1, a regulatory gene, may be involved in cardiac protection against heart failure.

METHODS

Clinical data analysis involved heart failure patients, while an animal model utilized C57BL/6J mice. RT-PCR, microarray analysis, histological examination, ELISA, and Western blot assays were employed to assess gene and protein expression, oxidative stress, and cardiac function. Cell transfection and culture of mouse atrial fibroblasts were performed for in-vitro experiments.

RESULTS

HACE1 expression was reduced in heart failure patients and correlated negatively with collagen levels. In mouse models, HACE1 up-regulation reduced oxidative stress, mitigated fibrosis, and improved cardiac function. Conversely, HACE1 knockdown exacerbated oxidative stress, fibrosis, and cardiac dysfunction. HACE1 also protected against ferroptosis and mitochondrial damage. NRF2, a transcription factor implicated in oxidative stress, was identified as a target of HACE1, with HACE1 promoting NRF2 activity through ubiquitination.

CONCLUSIONS

HACE1 emerges as a potential therapeutic target and diagnostic marker for heart failure. It regulates oxidative stress, mitigates cardiac fibrosis, and protects against ferroptosis and mitochondrial damage. The study reveals that HACE1 achieves these effects, at least in part, through NRF2 activation via ubiquitination, offering insights into novel mechanisms for heart failure pathogenesis and potential interventions.

Exosomes and their derivatives as biomarkers and therapeutic delivery agents for cardiovascular diseases: Situations and challenges

Microvesicles known as exosomes have a diameter of 40 to 160 nm and are derived from small endosomal membranes. Exosomes have attracted increasing attention over the past ten years in part because they are functional vehicles that can deliver a variety of lipids, proteins, and nucleic acids to the target cells they encounter. Because of this function, exosomes may be used for the diagnosis, prognosis and treatment of many diseases. All throughout the world, cardiovascular diseases (CVDs) continue to be a significant cause of death. Because exosomes are mediators of communication between cells, which contribute to many physiological and pathological aspects, they may aid in improving CVD therapies as biomarkers for diagnosing and predicting CVDs. Many studies demonstrated that exosomes are associated with CVDs, such as coronary artery disease, heart failure, cardiomyopathy and atrial fibrillation. Exosomes participate in the progression or inhibition of these diseases mainly through the contents they deliver. However, the application of exosomes in diferent CVDs is not very mature. So further research is needed in this field.

Advances in the study of exosomes derived from mesenchymal stem cells and cardiac cells for the treatment of myocardial infarction

Acute myocardial infarction has long been the leading cause of death in coronary heart disease, which is characterized by irreversible cardiomyocyte death and restricted blood supply. Conventional reperfusion therapy can further aggravate myocardial injury. Stem cell therapy, especially with mesenchymal stem cells (MSCs), has emerged as a promising approach to promote cardiac repair and improve cardiac function. MSCs may induce these effects by secreting exosomes containing therapeutically active RNA, proteins and lipids. Notably, normal cardiac function depends on intracardiac paracrine signaling via exosomes, and exosomes secreted by cardiac cells can partially reflect changes in the heart during disease, so analyzing these vesicles may provide valuable insights into the pathology of myocardial infarction as well as guide the development of new treatments. The present review examines how exosomes produced by MSCs and cardiac cells may influence injury after myocardial infarction and serve as therapies against such injury. Video Abstract.

Biogenesis, Composition and Potential Therapeutic Applications of Mesenchymal Stem Cells Derived Exosomes in Various Diseases

Exosomes are nanovesicles with a wide range of chemical compositions used in many different applications. Mesenchymal stem cell-derived exosomes (MSCs-EXOs) are spherical vesicles that have been shown to mediate tissue regeneration in a variety of diseases, including neurological, autoimmune and inflammatory, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells due to the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. MSCs-EXOs exhibit cytokine storm-mitigating properties in response to COVID-19. This review discussed the potential function of MSCs-EXOs in a variety of diseases including neurological, notably epileptic encephalopathy and Parkinson's disease, cancer, angiogenesis, autoimmune and inflammatory diseases. We provided an overview of exosome biogenesis and factors that regulate exosome biogenesis. Additionally, we highlight the functions and potential use of MSCs-EXOs in the treatment of the inflammatory disease COVID-19. Finally, we covered a strategies and challenges of MSCs-EXOs. Finally, we discuss conclusion and future perspectives of MSCs-EXOs.

Analysis of the Research Hotspot of Exosomes in Cardiovascular Disease: A Bibliometric-based Literature Review

OBJECTIVE

To investigate the current status and development trend of research on exosomes in cardiovascular disease (CVD) using bibliometric analysis and to elucidate trending research topics.

METHODS

Research articles on exosomes in CVD published up to April 2022 were retrieved from the Web of Science database. Data were organized using Microsoft Office Excel 2019. CiteSpace 6.1 and VOSviewer 1.6.18 were used for bibliometric analysis and result visualization.

RESULTS

Overall, 256 original research publications containing 190 fundamental research publications and 66 clinical research publications were included. "Extracellular vesicle" was the most frequent research keyword, followed by "microrna," "apoptosis," and "angiogenesis." Most publications were from China (187, 73.05%), followed by the United States (57, 22.27%), the United Kingdom (7, 2.73%), and Japan (7, 2.73%). A systematic review of the publications revealed that myocardial infarction and stroke were the most popular topics and that exosomes and their contents, such as microRNAs (miRNAs), play positive roles in neuroprotection, inhibition of autophagy and apoptosis, promotion of angiogenesis, and protection of cardiomyocytes.

CONCLUSION

Research on exosomes in CVD has attracted considerable attention, with China having the most published studies. Fundamental research has focused on CVD pathogenesis; exosomes regulate the progression of CVD through biological processes, such as the inflammatory response, autophagy, and apoptosis. Clinical research has focused on biomarkers for CVD; studies on using miRNAs in exosomes as disease markers for diagnosis could become a future trend.

Effect of miR-499-5p/SOX6 axis on atrial fibrosis in rats with atrial fibrillation

Atrial fibrosis is involved in the progression of atrial fibrillation (AF). miR-499-5p is the most downregulated microRNA in arrhythmogenic cardiomyopathy hearts. Sry-related high-mobility-group box 6 (SOX6) is associated with apoptosis, inflammatory responses, and fibrosis. This study investigated the mechanism of miR-499-5p in ameliorating AF rats by regulating SOX6. AF rat models were established by injecting Ach-CaCl₂ mixture, and the rats were treated with Lv-miR-499-5p/oe-SOX6/si-SOX6 before modeling. AF duration was recorded using electrocardiogram. miR-499-5p and SOX6 expression levels in the myocardium were determined by reverse transcription-quantitative polymerase chain reaction. The binding of miR-499-5p and SOX6 was validated. The atrial fibrosis degree and cardiomyocyte apoptosis were assessed using the Masson and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining methods. Levels of SOX6, atrial fibrosis markers (collage I/α-SMA/TGFβ1), cell cycle-related proteins (p21/CDC25/Cyclin B1), and cell senescence markers (SA-β-gal/γ-H2AX) were measured using Western blotting and immunohistochemistry. miR-499-5p was downregulated and SOX6 was upregulated in AF rats. miR-499-5p overexpression shortened the AF duration, alleviated atrial fibrosis, and decreased collage I/α-SMA/TGFβ1. miR-499-5p targeted SOX6 to ameliorate atrial fibrosis. AF rats exhibited increased p21/CDC25/Cyclin B1/SA-β-gal/γ-H2AX levels and raised cardiomyocyte apoptosis. SOX6 silencing downregulated p21 and alleviated cardiomyocyte cycle arrest, cell senescence, and apoptosis in AF rats. Shortly, miR-499-5p suppresses atrial fibrosis and cardiomyocyte senescence by targeting SOX6 and downregulating p21, thus mitigating AF in rats.

Can Extracellular Vesicles as Drug Delivery Systems Be a Game Changer in Cardiac Disease?

Cardiac diseases such as myocardial infarction and heart failure have been the leading cause of death worldwide for more than 20 years, and new treatments continue to be investigated. Heart transplantation, a curative treatment for severe cardiac dysfunction, is available to only a small number of patients due to the rarity of donors and high costs. Cardiac regenerative medicine using embryonic stem cells and induced pluripotent stem cells is expected to be a new alternative to heart transplantation, but it has problems such as induction of immune response, tumor formation, and low survival rate of transplanted cells. On the other hand, there has been a focus on cell-free therapy using extracellular vesicles (EVs) due to their high biocompatibility and target specificity. Exosomes, one type of EV, play a role in the molecular transport system in vivo and can be considered a drug delivery system (DDS) innate to all living things. Exosomes contain nucleic acids and proteins, which are transported from secretory cells to recipient cells. Molecules in exosomes are encapsulated in a lipid bilayer, which allows them to exist stably in body fluids without being affected by nuclease degradation enzymes. Therefore, the therapeutic use of exosomes as DDSs has been widely explored and is being used in clinical trials and other clinical settings. This review summarizes the current topics of EVs as DDSs in cardiac disease.

Research progress on the role of ferroptosis in cardiovascular disease

The cardiovascular disease pathogenesis is extremely complex and seriously threatens human health. Cardiomyocyte death plays a significant role in cardiovascular disease occurrence and development. In addition to the previously revealed modes of cell death (apoptosis, autophagy, and pyroptosis), ferroptosis is highly related to the development of cardiovascular diseases, including arrhythmia, atherosclerosis, and myocardial ischemia/reperfusion. Ferroptosis is a novel cell death pathway driven by lipid peroxidation and iron overload. Lipid, amino acid, and iron metabolism regulate the ferroptosis pathway. Small molecule compounds (iron chelators, antioxidants, and ferroptosis inhibitors) and genetic programming can alleviate or prevent cardiovascular disease by inhibiting the ferroptosis pathway. Ferroptosis plays a key role in various cardiovascular disease occurrence and development, and inhibiting ferroptosis in cardiomyocytes is expected to become a feasible treatment method. In this mini-review, we systematically summarize the molecular mechanisms of ferroptosis in different cardiovascular diseases, delineate the regulatory network between ferroptosis and cardiovascular diseases, and highlight its potential therapeutic targets.

Extracellular Vesicles in Atrial Fibrillation—State of the Art

Extracellular vesicles are particles released from cells and delimited by a lipid bilayer. They have been widely studied, including extensive investigation in cardiovascular diseases. Many scientists have explored their role in atrial fibrillation. Patients suffering from atrial fibrillation have been evidenced to present altered levels of these particles as well as changed amounts of their contents such as micro-ribonucleic acids (miRs). Although many observations have been made so far, a large randomized clinical trial is needed to assess the previous findings. This review aims to thoroughly summarize current research regarding extracellular vesicles in atrial fibrillation.