Inhibition of microRNA-155 attenuates sympathetic neural remodeling following myocardial infarction via reducing M1 macrophage polarization and inflammatory responses in mice

Zhen-wu-tang protects against myocardial fibrosis by inhibiting M1 macrophage polarization via the TLR4/NF-κB pathway

BACKGROUND

Myocardial fibrosis is a risk factor that contributes to the increase in the incidence of cardiovascular disease and death, posing a significant threat to human health. Zhen-wu-tang (ZWT) is a classical Chinese medicinal recipe that has been extensively used to manage cardiovascular disorders throughout history. However, the fundamental processes involved in its effects were not clear.

OBJECTIVE

This study examined the therapeutic effects of ZWT on myocardial fibrosis induced by isoproterenol (ISO) in mice, the effect of regulation and underlying mechanism on the polarization of M1 macrophage.

METHODS

In vivo, a myocardial fibrosis mouse model was induced via intraperitoneal infusion of isoproterenol (ISO). ZWT or captopril (CAP) was administered intragastrically for 30 days. Cardiac function was evaluated by electrocardiogram (ECG) and echocardiography. By analysing myocardial fibrosis pathomorphologically and identifying fibrosis-related indicators, the protective effect of the ZWT on the heart was evaluated. A model of macrophage polarization was established in vitro by activating RAW264.7 cells with lipopolysaccharide (LPS). The regulatory effects of ZWT on macrophage polarization and the signalling pathways involved were examined by immunofluorescence staining, Western blotting (WB), quantitative real-time PCR (qRT-PCR) and siRNA transfection.

RESULTS

ZWT improved cardiac function; reduced fibrotic deposition in cardiac tissues; decreased α-SMA, collagen I, and collagen III levels; and inhibited myocardial fibrosis in mice with ISO-induced myocardial fibrosis. Furthermore, the results showed that ZWT could suppress M1 macrophage polarization by downregulating the expression of CD86 and iNOS in vitro and in vivo. Finally, the results confirmed that ZWT could significantly reduce TLR4/NF-κB signalling pathway activation.

CONCLUSION

ZWT showed therapeutic effects on ISO-induced myocardial fibrosis mice, and reduced M1 macrophages polarization through inhibiting TLR4/NF-κB pathway, suggesting that ZWT is a promising drug for myocardial fibrosis treatment.

Macrophage-mediated heart repair and remodeling: A promising therapeutic target for post-myocardial infarction heart failure

Heart failure (HF) remains prevalent in patients who survived myocardial infarction (MI). Despite the accessibility of the primary percutaneous coronary intervention and medications that alleviate ventricular remodeling with functional improvement, there is an urgent need for clinicians and basic scientists to further reveal the mechanisms behind post-MI HF as well as investigate earlier and more efficient treatment after MI. Growing numbers of studies have highlighted the crucial role of macrophages in cardiac repair and remodeling following MI, and timely intervention targeting the immune response via macrophages may represent a promising therapeutic avenue. Recently, technology such as single-cell sequencing has provided us with an updated and in-depth understanding of the role of macrophages in MI. Meanwhile, the development of biomaterials has made it possible for macrophage-targeted therapy. Thus, an overall and thorough understanding of the role of macrophages in post-MI HF and the current development status of macrophage-based therapy will assist in the further study and development of macrophage-targeted treatment for post-infarction cardiac remodeling. This review synthesizes the spatiotemporal dynamics, function, mechanism and signaling of macrophages in the process of HF after MI, as well as discusses the emerging bio-materials and possible therapeutic agents targeting macrophages for post-MI HF.

Electroacupuncture Improves Cardiac Function via Inhibiting Sympathetic Remodeling Mediated by Promoting Macrophage M2 Polarization in Myocardial Infarction Mice

Electroacupuncture (EA) at the Neiguan acupoint (PC6) has shown significant cardioprotective effects. Sympathetic nerves play an important role in maintaining cardiac function after myocardial infarction (MI). Previous studies have found that EA treatment may improve cardiac function by modulating sympathetic remodeling after MI. However, the mechanism in how EA affects sympathetic remodeling and improves cardiac function remains unclear. The aim of this study is to investigate the cardioprotective mechanism of EA after myocardial ischemic injury by improving sympathetic remodeling and promoting macrophage M2 polarization. We established a mouse model of MI by occluding coronary arteries in male C57/BL6 mice. EA treatment was performed at the PC6 with current intensity (1 mA) and frequency (2/15 Hz). Cardiac function was evaluated using echocardiography. Heart rate variability in mice was assessed via standard electrocardiography. Myocardial fibrosis was evaluated by Sirius red staining. Levels of inflammatory factors were assessed using RT-qPCR. Sympathetic nerve remodeling was assessed through ELISA, western blotting, immunohistochemistry, and immunofluorescence staining. Macrophage polarization was evaluated using flow cytometry. Our results indicated that cardiac systolic function improved significantly after EA treatment, with an increase in fractional shortening and ejection fraction. Myocardial fibrosis was significantly mitigated in the EA group. The sympathetic nerve marker tyrosine hydroxylase and the nerve sprouting marker growth-associated Protein 43 were significantly reduced in the EA group, indicating that sympathetic remodeling was significantly reduced. EA treatment also promoted macrophage M2 polarization, reduced levels of inflammatory factors TNF-α, IL-1β, and IL-6, and decreased macrophage-associated nerve growth factor in myocardial tissue. To sum up, our results suggest that EA at PC6 attenuates sympathetic remodeling after MI to promote macrophage M2 polarization and improve cardiac function.

Pharmacological and molecular mechanisms of miRNA-based therapies for targeting cardiovascular dysfunction

Advances in understanding gene expression regulation through epigenetic mechanisms have contributed to elucidating the regulatory mechanisms of noncoding RNAs as pharmacological targets in several diseases. MicroRNAs (miRs) are a class of evolutionarily conserved, short, noncoding RNAs regulating in a concerted manner gene expression at the post-transcriptional level by targeting specific sequences of the 3'-untranslated region of mRNA. Conversely, mechanisms of cardiovascular disease (CVD) remain largely elusive due to their life-course origins, multifactorial pathophysiology, and co-morbidities. In this regard, CVD treatment with conventional medications results in therapeutic failure due to progressive resistance to monotherapy, which overlooks the multiple factors involved, and reduced adherence to poly-pharmacology approaches. Consequently, considering its role in regulating complete gene pathways, miR-based drugs have appreciably progressed into preclinical and clinical testing. This review summarizes the current knowledge about the mechanisms of miRs in cardiovascular disease, focusing specifically on describing how clinical chemistry and physics have improved the stability of the miR molecule. In addition, a comprehensive review of the main miRs involved in cardiovascular disease and the clinical trials in which these molecules are used as active pharmacological molecules is provided.

MicroRNA-155 and exosomal microRNA-155: Small pieces in the cardiovascular diseases puzzle

MicroRNAs (miRs, miRNAs) are known to have a part in various human illnesses, such as those related to the heart. One particular miRNA, miR-155, has been extensively studied and has been found to be involved in hematopoietic lineage differentiation, immunity, viral infections, inflammation, as well as vascular remodeling. These processes have all been connected to cardiovascular diseases, including heart failure, diabetic heart disease, coronary artery disease, and abdominal aortic aneurysm. The impacts of miR-155 depend on the type of cell it is acting on and the specific target genes involved, resulting in different mechanisms of disease. Although, the exact part of miR-155 in cardiovascular illnesses is yet not fully comprehended, as some studies have shown it to promote the development of atherosclerosis while others have shown it to prevent it. As a result, to comprehend the underlying processes of miR-155 in cardiovascular disorders, further thorough study is required. It has been discovered that exosomes that could be absorbed by adjacent or distant cells, control post-transcriptional regulation of gene expression by focusing on mRNA. Exosomal miRNAs have been found to have a range of functions, including participating in inflammatory reactions, cell movement, growth, death, autophagy, as well as epithelial-mesenchymal transition. An increasing amount of research indicates that exosomal miRNAs are important for cardiovascular health and have a major role in the development of a number of cardiovascular disorders, including pulmonary hypertension, atherosclerosis, acute coronary syndrome, heart failure, and myocardial ischemia-reperfusion injury. Herein the role of miR-155 and its exosomal form in heart diseases are summarized.

Recent advances in mechanistic studies of heart failure with preserved ejection fraction and its comorbidities-Role of microRNAs

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology commonly associated with comorbidities such as diabetes mellitus, obesity, hypertension and renal disease. Various diseases induce systemic, chronic and low-grade inflammation; microvascular dysfunction; metabolic stress; tissue ischemia; and fibrosis, leading to HFpEF. An effective treatment for HFpEF is lacking, largely owing to its pathophysiological heterogeneity. Recent studies have revealed that microRNAs (miRNAs) play crucial roles in regulating the pathogenesis of HFpEF and its comorbidities.

METHODS

This narrative review included original articles and reviews published over the past 20 years found through 'PubMed' and 'Web of Science'. The search terms included "HFpEF," "MicroRNAs," "comorbidities," "Microvascular Dysfunction (MVD)," "inflammation," "pathophysiology," "endothelial dysfunction," "energy metabolism abnormalities" "cardiac fibrosis" and "treatment."

RESULTS

Inflammation, MVD, abnormal energy metabolism, myocardial hypertrophy and myocardial fibrosis are important pathophysiological mechanisms underlying HFpEF. As gene expression regulators, miRNAs may contribute to the pathophysiology of HFpEF and are expected to serve in the stratification of patients with HFpEF and as prognostic indicators for monitoring treatment responses.

CONCLUSIONS

A customized strategy based on miRNAs has emerged as an effective treatment for HFpEF. In this review, we discuss recent research surrounding miRNAs and HFpEF and propose potential miRNA targets for the pathophysiology of HFpEF and its comorbidities. Although current research concerning miRNAs and their therapeutic potential is in its early stages, miRNA-based diagnostics and therapeutics hold great promise in the future.

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.

Bone marrow mesenchymal stem cells to ameliorate experimental autoimmune encephalomyelitis via modifying expression patterns of miRNAs

INTRODUCTION

Clinical and experimental studies highlighted the significant therapeutic role of Mesenchymal stem cells (MSCs) in neurodegenerative diseases. MSCs possess potent immunomodulatory properties by releasing exosomes, which generate a suitable microenvironment. microRNAs (miRNAs), as one of several effective bioactive molecules of exosomes, influence cellular communication and activities in recipient cells. Recent studies revealed that miRNAs could control the progression of multiple sclerosis (MS) via differentiation and function of T helper cells (Th).

METHODS

Here, we investigated the therapeutic effects of syngeneic-derived BM-MSC in experimental autoimmune encephalomyelitis (EAE) mouse model of MS by evaluating expression profile of miRNAs, pro- and anti-inflammatory in serum and brain tissues. Three-time scheme groups (6th day, 6th & 12th days, and 12th day, of post-EAE induction) were applied to determine the therapeutic effects of intraperitoneally received 1*106 of BM-MSCs.

RESULTS

The expression levels of mature isoforms of miR-193, miR-146a, miR-155, miR-21, and miR-326 showed that BM-MSCs treatment attenuated the EAE clinical score and reduced clinical inflammation as well as demyelination. The improved neurological functional outcome associated with enhanced expression of miR-193 and miR-146a, but decreased expression levels of miR-155, miR-21, and miR-326 were followed by suppressing effects on Th1/Th17 immune responses (reduced levels of IFN-γand IL-17 cytokine expression) and induction of Treg cells, immunoregulatory responses (increase of IL-10, TGF-β, and IL-4) in treatment groups.

CONCLUSION

Our findings suggest that BM-MSCs administration might change expression patterns of miRNAs and downstream interactions followed by immune system modulation. However, there is a need to carry out future human clinical trials and complementary experiments.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

lncRNA LOC100911717-targeting GAP43-mediated sympathetic remodeling after myocardial infarction in rats

Objective

Sympathetic remodeling after myocardial infarction (MI) is the primary cause of ventricular arrhythmias (VAs), leading to sudden cardiac death (SCD). M1-type macrophages are closely associated with inflammation and sympathetic remodeling after MI. Long noncoding RNAs (lncRNAs) are critical for the regulation of cardiovascular disease development. Therefore, this study aimed to identify the lncRNAs involved in MI and reveal a possible regulatory mechanism.

Methods and results

M0- and M1-type macrophages were selected for sequencing and screened for differentially expressed lncRNAs. The data revealed that lncRNA LOC100911717 was upregulated in M1-type macrophages but not in M0-type macrophages. In addition, the lncRNA LOC100911717 was upregulated in heart tissues after MI. Furthermore, an RNA pull-down assay revealed that lncRNA LOC100911717 could interact with growth-associated protein 43 (GAP43). Essentially, immunofluorescence assays and programmed electrical stimulation demonstrated that GAP43 expression was suppressed and VA incidence was reduced after lncRNA LOC100911717 knockdown in rat hearts using an adeno-associated virus.

Conclusions

We observed a novel relationship between lncRNA LOC100911717 and GAP43. After MI, lncRNA LOC100911717 was upregulated and GAP43 expression was enhanced, thus increasing the extent of sympathetic remodeling and the frequency of VA events. Consequently, silencing lncRNA LOC100911717 could reduce sympathetic remodeling and VAs.

Study on Maslinic Acid Inhibiting Cardiomyocyte Pyrolysis by Regulating TLR4/NFκB/NLRP3 Signaling Pathway

Background: The paper aimed to investigate the effects of Maslinic acid on myocardial injury caused by ischemia and hypoxia after acute myocardial infarction, and to explore the mechanism of Maslinic acid inhibiting local inflammation and myocardial cell pyrolysis, slowing down the synthesis of extracellular matrix, improving myocardial fibrosis and remodeling ventricle. Materials and Methods: Wistar rats with acute myocardial infarction were used. The serum levels of TNF-α, IL-1β, CRP, and LDH were detected by ELISA. The expressions of inflammation-related proteins such as TLR4, NFκB, NLRP3, IL-10, and TGF-β in myocardial infarction were detected by Western-blot. TUNEL method was employed to detect myocardial cell pyrolysis. Masson staining was used to detect myocardial fibrosis. Immunohistochemical method was applied to detect the expressions of CD206 and CD11C to understand the polarization of macrophages. Results: Maslinic acid can inhibit the levels of inflammatory factors such as CRP, TNF-α and IL-1β, and reduce the expression of myocardial TLR4, NFκB, NLRP3 and other inflammation-related proteins after myocardial infarction. The release of LDH is significantly reduced. The expression of TUNEL positive cells in myocardium is obviously reduced after myocardial infarction. Maslinic acid can increase the expression of CD206-positive cells and reduce the expression of CD11C-positive cells, thus regulate and promote polarization into M2 macrophages. Conclusion: Maslinic acid may inhibit myocardial cell pyrolysis and inflammatory response by regulating the TLR4/NFκB/NLRP3 signaling pathway. Maslinic acid can improve myocardial fibrosis by inhibiting myocardial cell pyrolysis and regulating the polarization of macrophages.

MiR-155-5p-SOCS1/JAK1/STAT1 participates in hepatic lymphangiogenesis in liver fibrosis and cirrhosis by regulating M1 macrophage polarization

BACKGROUND

The role and underlying mechanism of liver macrophages and their derived miR-155-5p in hepatic lymphangiogenesis in liver fibrosis remain unclear. Here, we investigated the mechanism by which macrophages and miR-155-5p were involved in lymphangiogenesis during liver fibrosis and cirrhosis.

METHODS

In vivo, hepatic lymphatic vessel expansion was evaluated; the liver macrophage subsets, proportion of peripherally-derived macrophages and expressions of CCL25, MCP-1, VAP-1 and MAdCAM-1 were documented; and miR-155-5p in the peripheral blood and liver was detected. In vitro, macrophages with miR-155-5p overexpression and inhibition were used to clarify the effect of miR-155-5p on regulation of macrophage polarization and the possible signalling pathway.

RESULTS

Hepatic lymphangiogenesis was observed in mice with liver fibrosis and cirrhosis challenged with carbon tetrachloride (CCl4). In the liver, the number of M1 macrophages was associated with lymphangiogenesis and the degree of fibrosis. The liver recruitment of peripherally-derived macrophages occurred during liver fibrosis. The levels of miR-155-5p in the liver and peripheral blood gradually increased with aggravation of liver fibrosis. In vitro, SOCS1, a target of miR-155-5p, regulated macrophage polarization into the M1 phenotype through the JAK1/STAT1 pathway.

CONCLUSION

MiR-155-5p-SOCS1/JAK1/STAT1 pathway participates in hepatic lymphangiogenesis in mice with liver fibrosis and cirrhosis induced by CCl4 by regulating the polarization of macrophages into the M1 phenotype.

Butyrate suppresses atherosclerotic inflammation by regulating macrophages and polarization via GPR43/HDAC-miRNAs axis in ApoE-/- mice

Chronic low-grade inflammation is regarded to an important signature of atherosclerosis (AS). Macrophage (Mψ) and related polarization have been demonstrated to play a crucial role in the occurrence and development of AS inflammation. Butyrate, a bioactive molecule produced by the intestinal flora, has been increasingly demonstrated to exhibit a vital role for regulating the inflammation in chronic metabolic diseases. However, the effectiveness and multiple anti-inflammation mechanisms of butyrate on AS still need to be further understood. ApoE-/- mice fed with high-fat diet as AS model were administered with sodium butyrate (NaB) for 14 weeks of treatment. Our results showed that the atherosclerotic lesion in the AS group was dramatically reduced after NaB intervention. Moreover, deteriorated routine parameters of AS including body weights (BWs), low-density lipoprotein (LDL-C), triglyceride (TG), total cholesterol (TC) were significantly reversed by NaB administration. Abnormal elevated plasma and aorta pro-inflammatory indicators including interleukin (IL)-1β, IL-6, IL-17A, tumor necrosis factor (TNF)-α and lipopolysaccharide (LPS), as well as reduced anti-inflammatory IL-10 in plasma were respectively rectified after NaB administration. Consistently, accumulated Mψ and associated imbalance of polarization in the arota were attenuated with NaB treatment. Importantly, we demonstrated that the suppression of Mψ and associated polarization of NaB was dependent on binding G-protein coupled receptor (GPR) and inhibiting histone deacetylase HDAC3. Moreover, we found that intestinal butyrate-producing bacteria, anti-inflammatory bacteria and intestinal tight junction protein zonula occludens-1 (ZO)-1 may contribute to this effectiveness. Intriguingly, according to transcriptome sequencing of atherosclerotic aorta, 29 elevated and 24 reduced miRNAs were found after NaB treatment, especially miR-7a-5p, suggesting that non-coding RNA may possess a potential role in the protection of NaB against AS. Correlation analysis showed that there were close complicated interactions among gut microbiota, inflammation and differential miRNAs. Collectively, this study revealed that dietary NaB may ameliorate atherosclerotic inflammation by regulating Mψ polarization via GPR43/HDAC-miRNAs axis in ApoE-/- mice.

Deregulated RNAs involved in sympathetic regulation of sepsis-induced acute lung injury based on whole transcriptome sequencing

Sympathetic nerves play essential roles in the regulation of lung inflammation, and we investigated the effect of sympathetic denervation (SD) on sepsis-induced acute lung injury (ALI) in mice. Mice were randomized to the control, SD, ALI and SD + ALI, groups. SD and ALI were established through intratracheal 6-hydroxydopamine and intraperitoneal lipopolysaccharide, respectively. Models and gene expressions levels were evaluated by HE staining, ELISA, Western blotting and RT-qPCR. RNA extraction, whole transcriptome sequencing and subsequent biostatistical analysis were performed. Sympathetic denervation in the lungs significantly attenuated lung TNF-ɑ and norepinephrine expression, alleviated sepsis-induced acute lung injury and inhibited NF-κB signaling. Compared with the ALI group, the SD + ALI group exhibited 629 DE circRNAs, 269 DE lncRNAs,7 DE miRNAs and 186 DE mRNAs, respectively. Some DE RNAs were validated by RT-qPCR. CircRNA-miRNA-mRNA regulatory networks in the SD + ALI group revealed enrichment of the B-cell receptor signaling pathway, IL-17 signaling pathway, neuroactive ligand-receptor interaction, CAM, primary immunodeficiency, and cytokine-cytokine receptor interaction terms. The lncRNA-miRNA-mRNA network also revealed inflammation-related signaling pathways. Taken together, based on the successfully established models of SD and ALI, we show here that sympathetic nerves may regulate sepsis-induced ALI supposedly by affecting the expression of circRNAs, lncRNAs, miRNAs, and mRNAs in the lungs. These results may allow for further exploration of the roles of pulmonary sympathetic nerves in sepsis-induced ALI.

A Review of Molecular Interplay between Neurotrophins and miRNAs in Neuropsychological Disorders

Various neurotrophins (NTs), including nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4, promote cellular differentiation, survival, and maintenance, as well as synaptic plasticity, in the peripheral and central nervous system. The function of microRNAs (miRNAs) and other small non-coding RNAs, as regulators of gene expression, is pivotal for the appropriate control of cell growth and differentiation. There are positive and negative loops between NTs and miRNAs, which exert modulatory effects on different signaling pathways. The interplay between NTs and miRNAs plays a crucial role in the regulation of several physiological and pathological brain procedures. Emerging evidence suggests the diagnostic and therapeutic roles of the interactions between NTs and miRNAs in several neuropsychological disorders, including epilepsy, multiple sclerosis, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, schizophrenia, anxiety disorders, depression, post-traumatic stress disorder, bipolar disorder, and drug abuse. Here, we review current data regarding the regulatory interactions between NTs and miRNAs in neuropsychological disorders, for which novel diagnostic and/or therapeutic strategies are emerging. Targeting NTs-miRNAs interactions for diagnostic or therapeutic approaches needs to be validated by future clinical studies.

Role of resveratrol in inhibiting pathological cardiac remodeling

Cardiovascular disease is a group of diseases with high mortality in clinic, including hypertension, coronary heart disease, cardiomyopathy, heart valve disease, heart failure, to name a few. In the development of cardiovascular diseases, pathological cardiac remodeling is the most common cardiac pathological change, which often becomes a domino to accelerate the deterioration of the disease. Therefore, inhibiting pathological cardiac remodeling may delay the occurrence and development of cardiovascular diseases and provide patients with greater long-term benefits. Resveratrol is a non-flavonoid polyphenol compound. It mainly exists in grapes, berries, peanuts and red wine, and has cardiovascular protective effects, such as anti-oxidation, inhibiting inflammatory reaction, antithrombotic, dilating blood vessels, inhibiting apoptosis and delaying atherosclerosis. At present, the research of resveratrol has made rich progress. This review aims to summarize the possible mechanism of resveratrol against pathological cardiac remodeling, in order to provide some help for the in-depth exploration of the mechanism of inhibiting pathological cardiac remodeling and the development and research of drug targets.

Cardiac Macrophages and Their Effects on Arrhythmogenesis

Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.

MicroRNA-155 inhibition attenuates myocardial infarction-induced connexin 43 degradation in cardiomyocytes by reducing pro-inflammatory macrophage activation

BACKGROUND

Degradation of pro-inflammatory macrophage-mediated connexin 43 (Cx43) plays an important role in post-myocardial infarction (MI) arrhythmogenesis, microRNA (miR)-155 produced by macrophages has been shown to mediate post-MI effects. We hypothesized that miR-155 inhibition attenuated MI-induced Cx43 degradation by reducing pro-inflammatory macrophage activation.

METHODS

MI was induced by permanent ligation of the left anterior descending coronary artery in male C57BL/6 mice. Lipopolysaccharide (LPS)-stimulated mice bone marrow-derived macrophages (BMDMs) and hypoxia-induced neonatal rat cardiomyocytes (NRCMs) were used in vitro models. qRT-PCR, Western-blot and immunofluorescence were used to analyze relevant indicators.

RESULTS

The expression levels of miR-155, interleukin-1 beta (IL-1β), and matrix metalloproteinase (MMP)7 were higher in MI mice and LPS-treated BMDMs than in the sham/control groups, treatment with a miR-155 antagomir reversed these effects. Moreover, miR-155 inhibition reduced ventricular arrhythmias incidence and improved cardiac function in MI mice. Cx43 expression was decreased in MI mice and hypoxia-exposed NRCMs, and hypoxia-induced Cx43 degradation in NRCMs was reduced by application of conditioned medium from LPS-induced BMDMs treated with the miR-155 antagomir, but increased by conditioned medium from BMDMs treated with a miR-155 agomir. Importantly, NRCMs cultured in conditioned medium from LPS-induced BMDMs transfected with small interfering RNA against IL-1β and MMP7 showed decreased hypoxia-mediated Cx43 degradation, and this effect also was diminished by BMDM treatment with the miR-155 agomir. Additionally, siRNA-mediated suppressor of cytokine signaling 1 (SOCS1) knockdown in LPS-induced BMDMs promoted Cx43 degradation in hypoxia-exposed NRCMs, and the effect was reduced by the miR-155 inhibition.

CONCLUSIONS

MiR-155 inhibition attenuated post-MI Cx43 degradation by reducing macrophage-mediated IL-1β and MMP7 expression through the SOCS1/nuclear factor-κB pathway.

Impact of Yiqi Huoxue Decoction on the Relationship between Remodeling of Cardiac Nerves and Macrophages after Myocardial Infarction in Rats

Sympathetic nerve remodeling after myocardial infarction (MI) has an indispensable role in cardiac remodeling. Numerous works have shown that sympathetic nerve remodeling can be delayed by inhibition of inflammatory response. Earlier studies have shown improvement in ventricular remodeling and inhibited chronic stage neural remodeling by Yiqi Huoxue decoction (YQHX). Therefore, the current study looked at the inhibitory effect of YQHX prescription on proinflammatory mediators and macrophages and the effect on neural remodeling at 3 and 7 days after MI. YQHX inhibited the expression of Toll-like receptor 4 (TLR4) and nuclear factor kappa B (NF-κB) proteins and macrophage infiltration within 7 days after myocardial infarction. YQHX could decrease Th-positive nerve fiber density in the area around infarction and reduce the expression of growth-associated protein 43 (GAP43), nerve growth factor (NGF), and tyrosine hydroxylase (TH) proteins, which was associated with the remodeling of sympathetic nerves. Thus, the nerve remodeling inhibition after MI due to YQHX may be through its anti-inflammatory action. These data provide direct evidence for the potential application of traditional Chinese medicine (TCM) in the remodeling of sympathetic nerves after MI.

Macrophage Polarization and Its Role in Liver Disease

Macrophages are important immune cells in innate immunity, and have remarkable heterogeneity and polarization. Under pathological conditions, in addition to the resident macrophages, other macrophages are also recruited to the diseased tissues, and polarize to various phenotypes (mainly M1 and M2) under the stimulation of various factors in the microenvironment, thus playing different roles and functions. Liver diseases are hepatic pathological changes caused by a variety of pathogenic factors (viruses, alcohol, drugs, etc.), including acute liver injury, viral hepatitis, alcoholic liver disease, metabolic-associated fatty liver disease, liver fibrosis, and hepatocellular carcinoma. Recent studies have shown that macrophage polarization plays an important role in the initiation and development of liver diseases. However, because both macrophage polarization and the pathogenesis of liver diseases are complex, the role and mechanism of macrophage polarization in liver diseases need to be further clarified. Therefore, the origin of hepatic macrophages, and the phenotypes and mechanisms of macrophage polarization are reviewed first in this paper. It is found that macrophage polarization involves several molecular mechanisms, mainly including TLR4/NF-κB, JAK/STATs, TGF-β/Smads, PPARγ, Notch, and miRNA signaling pathways. In addition, this paper also expounds the role and mechanism of macrophage polarization in various liver diseases, which aims to provide references for further research of macrophage polarization in liver diseases, contributing to the therapeutic strategy of ameliorating liver diseases by modulating macrophage polarization.

Targeting monocytes/macrophages in fibrosis and cancer diseases: Therapeutic approaches

Over almost 140 years since their identification, the knowledge about macrophages has unbelievably evolved. The 'big eaters' from being thought of as simple phagocytic cells have been recognized as master regulators in immunity, homeostasis, healing/repair and organ development. Long considered to originate exclusively from bone marrow-derived circulating monocytes, macrophages have been also demonstrated to be the first immune cells colonizing tissues in the developing embryo and persisting in adult life by self-renewal, as long-lived tissue resident macrophages. Therefore, heterogeneous populations of macrophages with different ontogeny and functions co-exist in tissues. Macrophages act as sentinels of homeostasis and are intrinsically programmed to lead the wound healing and repair processes that occur after injury. However, in certain pathological circumstances macrophages get dysfunctional, and impaired or aberrant macrophage activities become key features of diseases. For instance, in both fibrosis and cancer, that have been defined 'wounds that do not heal', dysfunctional monocyte-derived macrophages overall play a key detrimental role. On the other hand, due to their plasticity these cells can be 're-educated' and exert anti-fibrotic and anti-cancer functions. Therefore macrophages represent an important therapeutic target in both fibrosis and cancer diseases. The current review will illustrate new insights into the role of monocytes/macrophages in these devastating diseases and summarize new therapeutic strategies and applications of macrophage-targeted drug development in their clinical setting.

Effects of Yiqi Huoxue Decoction on Post-Myocardial Infarction Cardiac Nerve Remodeling and Cardiomyocyte Hypertrophy in Rats

Myocardial infarction can lead to ventricular remodeling and arrhythmia, which is closely related to nerve remodeling. Our previous study found that Yiqi Huoxue decoction (YQHX) can improve ventricular remodeling and reduce myocardial damage. Therefore, in this study, we observed the effect of YQHX on cardiac neural remodeling and cardiomyocyte hypertrophy and its possible mechanism. This research is composed of two parts: animal and H9c2 cells experiments. The animal model of acute myocardial infarction was established by ligating the left anterior descending coronary artery in Sprague Dawley (SD) rats. H9c2 cells were placed in 94% N₂, 5% CO₂, and 1% O₂ hypoxic environment for 12 hours to replicate the hypoglycemic hypoxia model. The experimental results showed that, compared with the MI group, YQHX can significantly improve heart function after myocardial infarction and reduce nerve remodeling and myocardial hypertrophy. Pathological structure observation demonstrated reducing myocardial tissue damage and decreasing of cell cross-sectional area, diameter, and circumference. The positive rate of TH declined apparently, and the sympathetic nerve density was lower than that of the MI group. After YQHX was given for 28 days, the proneural remodeling factors TH, NGF, and GAP43 in the marginal zone of infarction and stellate ganglion decreased obviously while the inhibitory nerve remodeling factor Sema-3A increased. The myocardial hypertrophic protein ANP and β-MHC were also significantly inhibited with p-ERK1/2 protein expression level prominently reduced. There was no difference between the YQHX group and the Meto group. After myocardial infarction, nerve remodeling was seen in the marginal area of infarction and stellate ganglion, and the neuropeptides released by which promoted myocardial hypertrophy. The mechanism may be related to the ERK1/2 signaling pathway. YQHX could regulate the ERK1/2 signaling pathway, inhibit the release of nerve remodeling factors and myocardial hypertrophy protein to reduce nerve remodeling, and relieve myocardial hypertrophy.

Exercising immune cells: The immunomodulatory role of exercise on atrial fibrillation

Exercise training is generally beneficial for cardiovascular health, improving stroke volume, cardiac output, and aerobic capacity. Despite these benefits, some evidence indicates that endurance training may increase the risk of atrial fibrillation (AF), particularly in highly trained individuals. Among multiple mechanisms, autonomic tone changes and atrial remodeling have been proposed as main contributors for exercise-induced AF. However, the contribution of local and systemic immunity is poorly understood in the development of atrial arrhythmogenic substrates. Here we aim to update the field of immunomodulation in the context of exercise and AF by compiling and reconciling the most recent evidence from preclinical and human studies and rationalize the applicability of "lone" AF terminology in athletes.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

Nerve-macrophage interactions in cardiovascular disease

The heart is highly innervated by autonomic neurons, and dynamic autonomic regulation of the heart and blood vessels is essential for animals to carry out the normal activities of life. Cardiovascular diseases, including heart failure and myocardial infarction, are often characterized in part by an imbalance in autonomic nervous system activation, with excess sympathetic and diminished parasympathetic activation. Notably, however, this is often accompanied by chronic inflammation within the cardiovascular tissues, which suggests there are interactions between autonomic dysregulation and inflammation. Recent studies have been unraveling the mechanistic links between autonomic nerves and immune cells within cardiovascular disease. The autonomic nervous system and immune system also act in concert to coordinate the actions of multiple organs that not only maintain homeostasis but also likely play key roles in disease-disease interactions, such as cardiorenal syndrome and multimorbidity. In this review, we summarize the physiological and pathological interactions between autonomic nerves and macrophages in the context of cardiovascular disease.

The Long Non-coding RNA NEAT1/miR-224-5p/IL-33 Axis Modulates Macrophage M2a Polarization and A1 Astrocyte Activation

To identify potential regulators and investigate the molecular mechanism of macrophage polarization affecting astrocyte activation from the perspective of non-coding RNA regulation, we isolated mouse bone marrow mononuclear cells (BMMNCs)-induced macrophages toward M1 or M2a polarization. Long non-coding RNA NEAT1 and IL-33 expression levels were significantly upregulated in M2a macrophages; NEAT1 knockdown in M2a macrophages markedly reduced the protein levels of IL-33 and M2a markers, IL-4 and IL-13 concentrations, and the bacterial killing capacity of M2a macrophages. NEAT1 acted as a competing endogenous RNA (ceRNA) to regulate IL-33 expression by sponging miR-224-5p in M2a macrophages; NEAT1 knockdown upregulated miR-224-5p expression, while miR-224-5p inhibition increased the protein content and concentration of IL-33. miR-224-5p inhibition exerted the opposite effects on the protein levels of IL-33 and M2a markers, IL-4 and IL-13 concentrations, and the bacterial killing capacity of M2a macrophages compared to NEAT1 knockdown; the effects of NEAT1 knockdown were significantly reversed by miR-224-5p inhibition. M2a macrophage conditioned medium (CM) significantly suppressed the activation of A1 astrocytes. NEAT1 knockdown M2a macrophage CM led to enhanced A1 astrocyte activation while miR-224-5p-silenced M2a macrophage CM led to a blockade of A1 astrocyte activation; the effects of NEAT1 knockdown M2a macrophage CM on A1 astrocyte activation were significantly reversed by miR-224-5p inhibition in M2a macrophages. The NEAT1/miR-224-5p/IL-33 axis modulates macrophage M2a polarization, therefore affecting A1 astrocyte activation.

Electroacupuncture improves cardiac function and reduces infarct size by modulating cardiac autonomic remodeling in a mouse model of myocardial ischemia

BACKGROUND

Sympathetic and parasympathetic nerve remodeling play an important role in cardiac function after myocardial ischemia (MI) injury. Increasing evidence indicates that electroacupuncture (EA) can regulate cardiac function by modulating the autonomic nervous system (ANS), but little is known about its effectiveness on neural remodeling post-MI.

OBJECTIVES

To investigate the role of EA in ANS remodeling post-MI.

METHODS

Adult male C57/BL6 mice were equally divided into the Control (Ctrl), MI and EA groups after generating the MI model by ligating the left anterior descending (LAD) coronary artery. Echocardiography and 2,3,5-triphenyltetrazolium (TTC) staining were employed to evaluate cardiac function and infarct size after EA treatment for five consecutive days. Serum norepinephrine (NE) levels were measured by ELISA to quantify sympathetic activation. Then, ANS remodeling was detected by immunohistochemistry (IHC), RT-qPCR, and Western blotting.

RESULTS

Our preliminary findings showed that EA increased ejection fraction and fractional shortening and reduced infarct area after MI injury. Serum NE levels in the EA group were significantly decreased compared with those in the MI group. IHC staining results demonstrated that the density of growth associated protein (GAP)43 and tyrosine hydroxylase (TH) positive nerve fibers in the EA group were decreased with increased choline acetyltransferase (CHAT) and vesicular acetylcholine transporter (VACHT). Meanwhile, the results verified that mRNA and protein expression of GAP43 and TH were significantly inhibited by EA treatment in the MI mice, accompanied by elevated CHAT and VACHT.

CONCLUSIONS

EA treatment could improve cardiac function and reduce infarct size by modulating sympathetic and parasympathetic nerve remodeling post-MI, thus helping the cardiac ANS reach a new balance to try to protect the heart from further possible injury.

miR-23a/b suppress cGAS-mediated innate and autoimmunity

Cyclic GMP-AMP synthase (cGAS), a key sensor of intracellular DNA, is essential for eliciting innate immunity against infection, whereas aberrant activation of cGAS by endogenous DNA promotes severe autoimmune diseases. However, it is largely unknown how cGAS expression is regulated during pathogen infection and autoimmunity. Here, we report that during herpes simplex virus type 1 (HSV-1) infection, two microRNAs (miR-23a and miR-23b) whose levels significantly decrease due to their interaction with the lncRNA Oasl2-209 directly regulate the expression of cGAS. Overexpression of miR-23a/b markedly dampens cytosolic DNA-induced innate immune responses, whereas inhibition of miR-23a/b enhances these responses. Mice treated with miR-23a/b agomirs exhibit increased susceptibility to HSV-1 infection. Moreover, cGAS is significantly upregulated in the Trex1-/- mouse autoimmune disease model. Administration of miR-23a/b blunts self DNA-induced autoinflammatory responses in Trex1-/- mice. Collectively, our study not only reveals a novel regulatory mechanism of cGAS expression by miRNAs but also identifies a potential therapy for cGAS-related autoimmune diseases.

Rian/miR-210-3p/Nfkb1 Feedback Loop Promotes Hypoxia-Induced Cell Apoptosis in Myocardial Infarction Through Deactivating the PI3K/Akt Signaling Pathway

Myocardial infarction (MI) is a severe disease that could lead to reversible or irreversible ischemic heart damage. A previous study has revealed that microRNA mmu-miR-210-3p expression is downregulated in fat-1 transgenic mice post-MI. Nevertheless, the specific mechanism of miR-210-3p in MI remains obscure. In this study, we observed that miR-210-3p expression was downregulated in the mice's left ventricle post-MI, and miR-210-3p expression was suppressed while cell apoptosis was promoted in H9c2 cells under hypoxia condition. Besides, miR-210-3p overexpression could enhance cell proliferation and inhibit cell apoptosis in hypoxia-treated H9c2 cells. Then, molecular mechanism assays revealed that miR-210-3p overexpression could activate the PI3K/Akt pathway, and nuclear factor of kappa light polypeptide gene enhancer in B cells 1 (Nfkb1) was the target of miR-210-3p. In addition, RNA imprinted and accumulated in nucleus (Rian), a long noncoding RNA, could sponge miR-210-3p to upregulate Nfkb1 expression. Besides, Nfkb1 was verified to facilitate the transcription of Rian by binding with a Rian promoter. Furthermore, rescue assays revealed that both Nfkb1 and PI3K/Akt pathway are engaged in the Rian-mediated cell proliferation and apoptosis in hypoxia-treated H9c2 cells. In conclusion, a Rian/miR-210-3p/Nfkb1 feedback loop enhances hypoxia-induced cell apoptosis in MI through deactivating the PI3K/Akt pathway.

MiR-155/GSK-3β mediates anti-inflammatory effect of Chikusetsusaponin IVa by inhibiting NF-κB signaling pathway in LPS-induced RAW264.7 cell

It has been demonstrated that Chikusetsusaponin IVa (CsIVa) possesses abundant biological activities. Herein, using LPS to establish acute inflammation model of mouse liver and cell line inflammation model, we investigated whether miR-155/GSK-3β regulated NF-κB signaling pathway, and CsIVa exerted anti-inflammatory effects by regulating miR-155/GSK-3β signaling pathway. Our results showed that LPS induced high expression of miR-155 and miR-155 promoted macrophage activation through GSK-3β. In addition, CsIVa inhibited inflammatory responses in LPS-induced mouse liver and RAW264.7 cells. Furthermore, we demonstrated that CsIVa improved the inflammatory response in LPS-induced RAW264.7 cells by inhibiting miR-155, increasing GSK-3β expression, and inhibiting NF-κB signaling pathway. In conclusion, our study reveals that CsIVa suppresses LPS-triggered immune response by miR-155/GSK-3β-NF-κB signaling pathway.

Harnessing noncoding RNA-based macrophage polarization: Emerging therapeutic opportunities for fibrosis

Aim

Organ fibrosis is a common pathological outcome of persistent tissue injury correlated with organ failure and death. Although current antifibrotic therapies have led to unprecedented successes, only a minority of patients with fibrosis benefit from these treatments. There is an urgent need to identify new targets and biomarkers that could be exploited in the diagnosis and treatment of fibrosis.

Methods

Macrophages play a dual role in the fibrogenesis across different organs either by promoting pro‐inflammatory or anti‐inflammatory responses. Noncoding RNAs (ncRNAs) have been demonstrated to play key roles in macrophage functions by manipulating macrophage polarization. Therefore, understanding the mechanism of ncRNA‐associated macrophage polarization is important to move toward therapeutic interventions.

Results

In this review, we provide an overview of recent insights into the role of ncRNAs in different fibrotic diseases by modulating macrophage phenotypic plasticity and functional heterogeneity. We also discuss the potential mechanisms of different ncRNAs integrate heterogeneous macrophages in fibrogenesis,including regulatory signatures, networks, and reciprocal interactions.

Conclusions

A broader understanding of how ncRNA‐directed macrophage phenotype transition in immunity and fibrosis might promote the development of a novel strategy for antifibrotic treatment.

Autotaxin inhibition reduces cardiac inflammation and mitigates adverse cardiac remodeling after myocardial infarction

OBJECTIVE

Acute myocardial infarction (AMI) initiates pathological inflammation which aggravates tissue damage and causes heart failure. Lysophosphatidic acid (LPA), produced by autotaxin (ATX), promotes inflammation and the development of atherosclerosis. The role of ATX/LPA signaling nexus in cardiac inflammation and resulting adverse cardiac remodeling is poorly understood.

APPROACH AND RESULTS

We assessed autotaxin activity and LPA levels in relation to cardiac and systemic inflammation in AMI patients and C57BL/6 (WT) mice. Human and murine peripheral blood and cardiac tissue samples showed elevated levels of ATX activity, LPA, and inflammatory cells following AMI and there was strong correlation between LPA levels and circulating inflammatory cells. In a gain of function model, lipid phosphate phosphatase-3 (LPP3) specific inducible knock out (Mx1-Plpp3^Δ) showed higher systemic and cardiac inflammation after AMI compared to littermate controls (Mx1-Plpp3^fl/fl); and a corresponding increase in bone marrow progenitor cell count and proliferation. Moreover, in Mx1- Plpp3^Δ mice, cardiac functional recovery was reduced with corresponding increases in adverse cardiac remodeling and scar size (as assessed by echocardiography and Masson's Trichrome staining). To examine the effect of ATX/LPA nexus inhibition, we treated WT mice with the specific pharmacological inhibitor, PF8380, twice a day for 7 days post AMI. Inhibition of the ATX/LPA signaling nexus resulted in significant reduction in post-AMI inflammatory response, leading to favorable cardiac functional recovery, reduced scar size and enhanced angiogenesis.

CONCLUSION

ATX/LPA signaling nexus plays an important role in modulating inflammation after AMI and targeting this mechanism represents a novel therapeutic target for patients presenting with acute myocardial injury.

Long non-coding RNA HCG18 promotes M1 macrophage polarization through regulating the miR-146a/TRAF6 axis, facilitating the progression of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most important complications in diabetes mellitus (DM), which has been reported to be modulated by long non-coding RNAs (lncRNAs). The purpose of the current study is to explore the regulatory mechanism of lncRNA HCG18 on DPN in vitro. The expression of lncRNA HCG18, miR-146a, TRAF6, CD11c, and iNOS was detected by qRT-PCR. Through Enzyme-linked immunosorbent assay, the levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were determined. M1 macrophage polarization was measured by flow cytometry analysis. The interactions between miR-146a and HCG18/TRAF6 were predicted by Starbase/Targetscan software and verified by the dual luciferase reporter assay. Western blot assay was performed to determine the protein expression of TRAF6. LncRNA HCG18 was highly expressed in DPN model and HG-induced macrophages. The levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were elevated in DPN model. The expression of M1 markers (CD11c and iNOS) was visibly up-regulated in DPN model and was positively correlated with HCG18 expression. LncRNA HCG18 facilitated M1 macrophage polarization. In addition, miR-146a was identified as a target of lncRNA HCG18. Overexpression of miR-146a reversed the promoting effect of HCG18 on M1 macrophage polarization. Simultaneously, TRAF6 was a target gene of miR-146a TRAF6 expression was positively modulated by HCG18 and was negatively modulated by miR-146a. Down-regulation of TRAF6 reversed the promoting effect of HCG18 on M1 macrophage polarization. LncRNA HCG18 promotes M1 macrophage polarization via regulating the miR-146a/TRAF6 axis, facilitating the progression of DPN. This study provides a possible therapeutic strategy for DPN.

The Role of Cardiac Macrophage and Cytokines on Ventricular Arrhythmias

In the heart, cardiac macrophages have widespread biological functions, including roles in antigen presentation, phagocytosis, and immunoregulation, through the formation of diverse cytokines and growth factors; thus, these cells play an active role in tissue repair after heart injury. Recent clinical studies have indicated that macrophages or elevated inflammatory cytokines secreted by macrophages are closely related to ventricular arrhythmias (VAs). This review describes the role of macrophages and macrophage-secreted inflammatory cytokines in ventricular arrhythmogenesis.

The Role of Non-coding RNAs in Ischemic Myocardial Reperfusion Injury

MicroRNAs (miRNA) are non-coding RNAs that regulate gene expression in up to 90% of the human genome through interactions with messenger RNA (mRNA). The expression of miRNAs varies and changes in diseased and healthy states, including all stages of myocardial ischemia-reperfusion and subsequent ischemia-reperfusion injury (IRI). These changes in expression make miRNAs an attractive potential therapeutic target. Herein, we review the differences in miRNA expression prior to ischemia (including remote ischemic conditioning and ischemic pre-conditioning), the changes during ischemia-reperfusion, and the changes in miRNA expression after IRI, with an emphasis on inflammatory and fibrotic pathways. Additionally, we review the effects of manipulating the levels of certain miRNAs on changes in infarct size, inflammation, remodeling, angiogenesis, and cardiac function after either ischemia-reperfusion or permanent coronary ligation. Levels of target miRNA can be increased using molecular mimics ("agomirs"), or can be decreased by using "antagomirs" which are antisense molecules that act to bind and thus inactivate the target miRNA sequence. Other non-coding RNAs, including long non-coding RNAs and circular RNAs, also regulate gene expression and have a role in the regulation of IRI pathways. We review the mechanisms and downstream effects of the miRNAs that have been studied as therapy in both permanent coronary ligation and ischemia-reperfusion models.

Resveratrol prevents ISO-induced myocardial remodeling associated with regulating polarization of macrophages through VEGF-B/AMPK/NF-kB pathway

Macrophage expansion and inflammatory responses are involved in induction of cardiac remodeling. Resveratrol has strong anti-inflammatory effects, however its effect on macrophage infiltration and polarization is unknown. This study aimed to investigate the anti-inflammatory effects of RSV on ISO-induced myocardial remodeling in mice and its regulatory role in macrophage polarization. BALB/c mice were orally administered with RSV (100 mg/kg) daily for one week, then were subcutaneously injected with ISO (50 mg/kg) daily for another week. ISO injections to mouse caused cardiac dysfunction evidenced by cardiac hypertrophy and cardiomyocyte fibrosis. Meanwhile, macrophage M1 polarization was found in ISO treated mice, which was evidenced by increased percentage of Ly6C^low macrophages in the heart, levels of M1 cytokines and expression of CD68, and decreased percentage of Ly6C^high macrophage, levels of M2 cytokines and expression of CD206. All these changes in cardiac and macrophage M1 polarization were ameliorated when mice were pretreated with RSV. The effect of RSV on macrophage polarization was also tested in RAW264.7 cells. It was found that pre-treatment with RSV decreased the levels of M1 marker or proinflammatory cytokines, while increased the levels of M2 markers in ISO treated cells. In addition, it was found that RSV could upregulate the expression of VEGF-B and the activity of AMPK, while it downregulated the expression of phosphorylated NF-κB p65 both in RAW264.7 cells and in mice. Furthermore, pretreatment with VEGF-B siRNA greatly reversed changes in almost all above parameters evoked by RSV in RAW264.7 cells. Therefore, our findings suggest RSV has potential therapeutic effects in ISO-induced myocardial injury, which may be by inhibiting the M1 polarization of macrophages through VEGFB/AMPK/NF-кB pathway.

Macrophages: First guards in the prevention of cardiovascular diseases

Cardiovascular diseases (CVD) remain one of the leading causes of mortality worldwide, especially in developing countries. It is widely known that severe inflammation can lead to atherosclerosis, which can cause various downstream pathologies, including myocardial injury and viral myocarditis. To date, several strategies have been proposed to prevent and cure CVD. The use of targeting macrophages has emerged as one of the most effective therapeutic approaches. Macrophages play a crucial role in eliminating senescent and dead cells while maintaining myocardial electrical activity and repairing myocardial injury. They also contribute to tissue repair and remodeling and plaque stabilization. Targeting macrophage pathways can, therefore, be advantageous in CVD care since it can lead to decreased aggregation of mononuclear cells at the injured site in the heart. Furthermore, it inhibits the development of pro-inflammatory factors, facilitates cholesterol outflow, and reduces the lipid concentration. More in-depth studies are still needed to formulate a comprehensive classification of phenotypes for different macrophages and determine their roles in the pathogenesis of CVD. In this review, we summarize the recent advances in the understanding of the role of macrophages in the prevention and cure of CVD.

Nerve growth factor promotes ASIC1a expression via the NF-κB pathway and enhances acid-induced chondrocyte apoptosis

Nerve growth factor (NGF) is a neurotrophic factor that is thought to have a broad role in the nervous system and tumors, and has recently been described as a mediator of inflammation. It is not clear whether or not NGF participates in apoptosis of articular chondrocytes. In this study, we determined if NGF affects ASIC1a expression and NF-κB P65 activation in rat chondrocytes, and measured the effectiveness of NGF on apoptotic protein expression in acid-induced chondrocytes. NGF was shown to up-regulate the level of ASIC1a in a dose- and time-dependent fashion. Simultaneously, NGF activated NF-κB P65 in chondrocytes. Additionally, the elevated ASIC1a expression induced by NGF was eliminated by the NF-κB inhibitor (PDTC) in chondrocytes. Moreover, NGF reduced cell viability and induced LDH release under the premise of acid-induced articular chondrocytes. Furthermore, NGF could enhance cleaved-caspase 9 and cleaved-PARP expression in acid-pretreated chondrocytes, and which could be inhibited by using psalmotoxin 1(PcTX1) or PDTC. Together, these results indicated that NGF may up-regulate ASIC1a expression through the NF-κB signaling pathway, and further promote acid-induced apoptosis of chondrocytes.

M1-like macrophage-derived exosomes suppress angiogenesis and exacerbate cardiac dysfunction in a myocardial infarction microenvironment

The roles and the underlying mechanisms of M1-type macrophages in angiogenesis and postmyocardial infarction (MI) cardiac repair have remained unclear. In this study, we investigated the role of M1-like macrophage-derived exosomes in a MI microenvironment. We found that the proinflammatory M1-like-type macrophages released an extensive array of proinflammatory exosomes (M1-Exos) after MI. M1-Exos exerted an anti-angiogenic effect and accelerated MI injury. They also exhibited highly expressed proinflammatory miRNAs, such as miR-155. miR-155 was transferred to endothelial cells (ECs), leading to the inhibition of angiogenesis and cardiac dysfunction by downregulating its novel target genes, including Rac family small GTPase 1 (RAC1), p21 (RAC1)-activated kinase 2 (PAK2), Sirtuin 1 (Sirt1), and protein kinase AMP-activated catalytic subunit alpha 2 (AMPKα2). M1-Exos depressed Sirt1/AMPKα2-endothelial nitric oxide synthase and RAC1-PAK2 signaling pathways by simultaneously targeting the five molecule nodes (genes), reduced the angiogenic ability of ECs, aggravated myocardial injury, and restrained cardiac healing. The elucidation of this mechanism provides novel insights into the functional significance of M1 macrophages and their derived exosomes on angiogenesis and cardiac repair. This mechanism can be used as a novel potential therapeutic approach for the prevention and treatment of MI.

Butyrate improves cardiac function and sympathetic neural remodeling following myocardial infarction in rats

Increased inflammation is found in cardiac sympathetic neural remodeling with malignant ventricular arrhythmia (VA) following myocardial infarction (MI). Butyrate, as a microbiota-derived short-chain fatty acid, can inhibit inflammation and myocardial hypertrophy. However, the role of butyrate in sympathetic neural remodeling after MI is unknown. This study aimed to investigate whether butyrate could improve cardiac dysfunction and VA following MI by regulating inflammation and sympathetic neural remodeling. MI rats were randomized to administrate the butyrate or vehicle through intraperitoneal injection to undergo the study. Our data demonstrated that butyrate treatment preserved the partial cardiac function at 7 days post-MI. Butyrate downregulated the expression of essential for inflammatory response in the infarct border zone at 3 days post-MI. Particularly, butyrate promoted expression of M2 macrophage markers. Increased expressions of nerve growth factor and norephinephrine at 7 days after MI were inhibited in butyrate-treated rats. Furthermore, butyrate significantly decreased the density of nerve fibers for growth-associated protein-43 and tyrosine hydroxylase and resulted in fewer episodes of inducible VA. In conclusion, butyrate administration ameliorated cardiac function and VA after MI possibly through promoting M2 macrophage polarization to suppress inflammatory responses and inhibit sympathetic neural remodeling and may present an effective pharmacological strategy for the prevention of MI-related remodeling.

Drug delivery to macrophages: A review of targeting drugs and drug carriers to macrophages for inflammatory diseases

Macrophages play a key role in defending against foreign pathogens, healing wounds, and regulating tissue homeostasis. Driving this versatility is their phenotypic plasticity, which enables macrophages to respond to subtle cues in tightly coordinated ways. However, when this coordination is disrupted, macrophages can aid the progression of numerous diseases, including cancer, cardiovascular disease, and autoimmune disease. The central link between these disorders is aberrant macrophage polarization, which misguides their functional programs, secretory products, and regulation of the surrounding tissue microenvironment. As a result of their important and deterministic roles in both health and disease, macrophages have gained considerable attention as targets for drug delivery. Here, we discuss the role of macrophages in the initiation and progression of various inflammatory diseases, summarize the leading drugs used to regulate macrophages, and review drug delivery systems designed to target macrophages. We emphasize strategies that are approved for clinical use or are poised for clinical investigation. Finally, we provide a prospectus of the future of macrophage-targeted drug delivery systems.