Macrophage Polarization, Metabolic Reprogramming, and Inflammatory Effects in Ischemic Heart Disease

Myeloid deficiency of Z-DNA binding protein 1 restricts septic cardiomyopathy via promoting macrophage polarisation towards the M2-subtype

BACKGROUND

Septic cardiomyopathy is a frequent complication in patients with sepsis and is associated with a high mortality rate. Given its clinical significance, understanding the precise underlying mechanism is of great value.

METHODS AND RESULTS

Our results unveiled that Z-DNA binding protein 1 (ZBP1) is upregulated in myocardial tissues of lipopolysaccharide (LPS)-treated mice. Single-cell mRNA sequencing (scRNA-seq) and single-nucleus mRNA sequencing (snRNA-seq) indicated that Zbp1 mRNA in endothelial cells, fibroblasts and macrophages appeared to be elevated by LPS, which is partially consistent with the results of immunofluorescence. Through echocardiography, we identified that global deletion of ZBP1 improves cardiac dysfunction and the survival rate of LPS-treated mice. Mechanistically, snRNA-seq showed that ZBP1 is mainly expressed in macrophages and deletion of ZBP1 promotes the macrophage polarisation towards M2-subtype, which reduces inflammatory cell infiltration. Notably, myeloid-specific deficiency of ZBP1 also promotes M2 macrophage polarisation and improves cardiac dysfunction, validating the role of macrophage-derived ZBP1 in septic myocardial dysfunction. Finally, we revealed that LPS increases the transcription and expression of ZBP1 through signal transducer and activator of transcription 1 (STAT1). Fludarabine, the inhibitor of STAT1, could also promote M2 macrophage polarisation and improve cardiac dysfunction of LPS-treated mice.

CONCLUSIONS

Our study provides evidence of a novel STAT1-ZBP1 axis in macrophage promoting septic cardiomyopathy, and underscores the potential of macrophage-derived ZBP1 as a therapeutic target for septic cardiomyopathy.

KEY POINTS

Macrophage-derivedZBP1 exacerbates LPS-induced myocardial dysfunction and inflammatory cellinfiltration. Deletionof ZBP1 promotes macrophage polarisation from M1 to M2. STAT1-ZBP1axis promotes septic cardiomyopathy. ZBP1has emerged as a potential therapeutic target for inflammationand septic cardiomyopathy.

Polychlorinated biphenyls induce immunometabolic switch of antiinflammatory macrophages toward an inflammatory phenotype

Polychlorinated biphenyls (PCBs) are a group of environmental toxicants associated with increased risk of diabetes, obesity, and metabolic syndrome. These metabolic disorders are characterized by systemic and local inflammation within adipose tissue, the primary site of PCB accumulation. These inflammatory changes arise when resident adipose tissue macrophages undergo phenotypic plasticity-switching from an antiinflammatory to an inflammatory phenotype. Thus, we sought to assess whether PCB exposure drives macrophage phenotypic switching. We investigated how human monocyte-derived macrophages polarized toward an M1, M2a, or M2c phenotype were impacted by exposure to Aroclor 1254, a PCB mixture found at high levels in school air. We showed that PCB exposure not only exacerbates the inflammatory phenotype of M1 macrophages but also shifts both M2a and M2c cells toward a more inflammatory phototype in both a dose- and time-dependent manner. Additionally, we show that PCB exposure leads to significant metabolic changes. M2 macrophages exposed to PCBs exhibit increased reliance on aerobic glycolysis and reduced capacity for fatty acid and amino acid oxidation-both indicators of an inflammatory macrophage phenotype. Collectively, these results demonstrate that PCBs promote immunometabolic macrophage plasticity toward a more M1-like phenotype, thereby suggesting that PCBs exacerbate metabolic diseases by altering the inflammatory environment in adipose tissue.

O-linked β-N-acetylglucosamine transferase regulates macrophage polarization in diabetic periodontitis: In vivo and in vitro study

BACKGROUND

Periodontitis, when exacerbated by diabetes, is characterized by increased M1 macrophage polarization and decreased M2 polarization. O-linked β-N-acetylglucosamine (O-GlcNAcylation), catalyzed by O-GlcNAc transferase (OGT), promotes inflammatory responses in diabetic periodontitis (DP). Additionally, p38 mitogen-activated protein kinase regulates macrophage polarization. However, the interplay between OGT, macrophage polarization, and p38 signaling in the progression of DP remains unexplored.

AIM

To investigate the effect of OGT on macrophage polarization in DP and its role in mediating O-GlcNAcylation of p38.

METHODS

For in vivo experiments, mice were divided into four groups: Control, DP model, model + short hairpin (sh) RNA-negative control, and model + sh-OGT. Diabetes was induced by streptozotocin, followed by ligation and lipopolysaccharide (LPS) administration to induce periodontitis. The impact of OGT was assessed by injecting sh-OGT lentivirus. Maxillary bone destruction was evaluated using micro-computed tomography analysis and tartrate-resistant acid phosphatase staining, while macrophage polarization was determined through quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry. For in vitro experiments, RAW264.7 cells were treated with LPS and high glucose (HG) (25 mmol/L D-glucose) to establish a cell model of DP. OGT was inhibited by OGT inhibitor (OSMI4) treatment and knocked down by sh-OGT transfection. M1/M2 polarization was analyzed using qPCR, immunofluorescence, and flow cytometry. Levels of O-GlcNAcylation were measured using immunoprecipitation and western blotting.

RESULTS

Our results demonstrated that M1 macrophage polarization led to maxillary bone loss in DP mice, associated with elevated O-GlcNAcylation and OGT levels. Knockdown of OGT promoted the shift from M1 to M2 macrophage polarization in both mouse periodontal tissues and LPS + HG-induced RAW264.7 cells. Furthermore, LPS + HG enhanced the O-GlcNAcylation of p38 in RAW264.7 cells. OGT interacted with p38 to promote its O-GlcNAcylation at residues A28, T241, and T347, as well as its phosphorylation at residue Y221.

CONCLUSION

Inhibition of OGT-mediated p38 O-GlcNAcylation deactivates the p38 pathway by suppressing its self-phosphorylation, thereby promoting M1 to M2 macrophage polarization and mitigating DP. These findings suggested that modulating macrophage polarization through regulation of O-GlcNAcylation may represent a novel therapeutic strategy for treating DP.

Itaconate: A Nexus Metabolite Fueling Leishmania Survival Through Lipid Metabolism Modulation

Leishmaniasis, caused by the Leishmania parasite, is a neglected public health issue. Leishmania mainly infects macrophages, where metabolic reprogramming shapes their plasticity (M1/M2), affecting the host's resistance or susceptibility to infection. The development of this infection is influenced by immune responses, with an excessive anti-inflammatory reaction linked to negative outcomes through the modulation of various mediators. Itaconate, produced by the Acod1 gene, is recognized for its anti-inflammatory effects, but its function in leishmaniasis is not well understood. This study aimed to investigate the potential role of itaconate in leishmaniasis. Using transcriptomic data from L. major-infected BMDMs, we assessed the expression dynamics of Il1b and Acod1 and performed pathway enrichment analysis to determine the profile of genes co-expressed with Acod1. Early Acod1 upregulation followed by later Il1b downregulation was noted, indicating a shift towards an anti-inflammatory response. Among the genes co-expressed with Acod1, Ldlr, Hadh, and Src are closely associated with lipid metabolism and the polarization of macrophages towards the M2 phenotype, thereby creating a favorable environment for the survival of Leishmania. Overall, these findings suggest that Acod1 and its co-expressed genes may affect the outcome of Leishmania infection by modulating host metabolism. Accordingly, targeting itaconate-associated pathways could provide a novel therapeutic strategy for leishmaniasis.

Bacterial-Mediated In Situ Engineering of Tumour-Associated Macrophages for Cancer Immunotherapy

BACKGROUND/OBJECTIVES

Tumour-associated macrophages (TAMs) are critical components of the tumour microenvironment (TME), significantly influencing cancer progression and treatment resistance. This review aims to explore the innovative use of engineered bacteria to reprogram TAMs, enhancing their anti-tumour functions and improving therapeutic outcomes.

METHODS

We conducted a systematic review following a predefined protocol. Multiple databases were searched to identify relevant studies on TAMs, their phenotypic plasticity, and the use of engineered bacteria for reprogramming. Inclusion and exclusion criteria were applied to select studies, and data were extracted using standardised forms. Data synthesis was performed to summarise the findings, focusing on the mechanisms and therapeutic benefits of using non-pathogenic bacteria to modify TAMs.

RESULTS

The review summarises the findings that engineered bacteria can selectively target TAMs, promoting a shift from the tumour-promoting M2 phenotype to the tumour-fighting M1 phenotype. This reprogramming enhances pro-inflammatory responses and anti-tumour activity within the TME. Evidence from various studies indicates significant tumour regression and improved immune responses following bacterial therapy.

CONCLUSIONS

Reprogramming TAMs using engineered bacteria presents a promising strategy for cancer therapy. This approach leverages the natural targeting abilities of bacteria to modify TAMs directly within the tumour, potentially improving patient outcomes and offering new insights into immune-based cancer treatments. Further research is needed to optimise these methods and assess their clinical applicability.

Probiotic-Derived Metabolites from Lactiplantibacillus plantarum OC01 Reprogram Tumor-Associated Macrophages to an Inflammatory Anti-Tumoral Phenotype: Impact on Colorectal Cancer Cell Proliferation and Migration

Background: Tumor-associated macrophages (TAMs) are key players in the colorectal cancer (CRC) tumor microenvironment (TME), representing the most abundant immune cells within it. The interplay between the intestinal microbiota, macrophages, and cancer cells significantly impacts tumor progression by driving macrophage polarization. Particularly, the polarization into the pro-tumoral M2-like TAM phenotype promotes the extracellular matrix remodeling, cancer cell proliferation, metastasis, immune suppression, and therapy resistance. Probiotic metabolites can disrupt this crosstalk, possibly reverting the TAM polarization toward a pro-inflammatory anti-tumoral phenotype, thus potentially benefiting the intestinal mucosa and opposing CRC progression. Previously, we showed that Lactiplantibacillus plantarum OC01 metabolites counter interleukin (IL)-6-induced CRC proliferation and migration. Methods: Here, we explore how probiotics affect CRC secretome and how this influences TAM polarization, which then impacts CRC malignancy. Results: The conditioning medium (CM) from CRC cells indeed promoted the polarization of macrophage toward the M2-like phenotype, whereas the CM from CRC pre-treated with L. plantarum OC01 metabolites induced a pro-inflammatory macrophage phenotype, characterized by NLRP3 inflammasome activation and reactive oxygen species (ROS) production, and by decreased expression of the M2 phenotype markers CD206 and CD163. Consistently, the expression of tumor growth factor (TGF)-β, a promoter of M2 macrophage polarization, was reduced in CRC cells treated with L. plantarum OC01. The pro-inflammatory macrophages inhibited CRC proliferation and migration. Conclusions: Overall, our study highlights the potential of metabolites from L. plantarum OC01 to reprogram the metabolism in cancer cells and thus reshape the TME by shifting TAMs toward a more inflammatory and anti-tumoral phenotype, emphasizing the promise of probiotics in advancing novel therapeutic approaches for CRC.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end-stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T-lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell-based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell-targeted therapy for IHD.

Comprehensive macro and micro views on immune cells in ischemic heart disease

Ischemic heart disease (IHD) is a prevalent cardiovascular condition that remains the primary cause of death due to its adverse ventricular remodelling and pathological changes in end‐stage heart failure. As a complex pathologic condition, it involves intricate regulatory processes at the cellular and molecular levels. The immune system and cardiovascular system are closely interconnected, with immune cells playing a crucial role in maintaining cardiac health and influencing disease progression. Consequently, alterations in the cardiac microenvironment are influenced and controlled by various immune cells, such as macrophages, neutrophils, dendritic cells, eosinophils, and T‐lymphocytes, along with the cytokines they produce. Furthermore, studies have revealed that Gata6+ pericardial cavity macrophages play a key role in regulating immune cell migration and subsequent myocardial tissue repair post IHD onset. This review outlines the role of immune cells in orchestrating inflammatory responses and facilitating myocardial repair following IHD, considering both macro and micro views. It also discusses innovative immune cell‐based therapeutic strategies, offering new insights for further research on the pathophysiology of ischemic heart disease and immune cell‐targeted therapy for IHD.

Macrophage polarization and metabolic reprogramming in abdominal aortic aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) is a macrovascular disease with high morbidity and mortality in the elderly. The limitation of the current management is that most patients can only be followed up until the AAA diameter increases to a threshold, and surgical intervention is recommended. The development of preventive and curative drugs for AAA is urgently needed. Macrophage-mediated immune inflammation is one of the key pathological links in the occurrence and development of AAA.

AIMS

This review article aims to evaluate the impact of immunometabolism on macrophage biology and its role in AAA.

METHODS

We analyze publications focusing on the polarization and metabolic reprogramming in macrophages as well as their potential impact on AAA, and summarize the potential interventions that are currently available to regulate these processes.

RESULTS

The phenotypic and functional changes in macrophages are accompanied by significant alterations in metabolic pathways. The interaction between macrophage polarization and metabolic pathways significantly influences the progression of AAA.

CONCLUSION

Macrophage polarization is a manifestation of the gross dichotomy of macrophage function into pro-inflammatory killing and tissue repair, that is, classically activated M1 macrophages and alternatively activated M2 macrophages. Macrophage functions are closely linked to metabolic changes, and the emerging field of immunometabolism is providing unique insights into the role of macrophages in AAA. It is essential to further investigate the precise metabolic changes and their functional consequences in AAA-associated macrophages.

Cardiac macrophages in maintaining heart homeostasis and regulating ventricular remodeling of heart diseases

Macrophages are most important immune cell population in the heart. Cardiac macrophages have broad-spectrum and heterogeneity, with two extreme polarization phenotypes: M1 pro-inflammatory macrophages (CCR2-ly6Chi) and M2 anti-inflammatory macrophages (CCR2-ly6Clo). Cardiac macrophages can reshape their polarization states or phenotypes to adapt to their surrounding microenvironment by altering metabolic reprogramming. The phenotypes and polarization states of cardiac macrophages can be defined by specific signature markers on the cell surface, including tumor necrosis factor α, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), C-C chemokine receptor type (CCR)2, IL-4 and arginase (Arg)1, among them, CCR2+/- is one of most important markers which is used to distinguish between resident and non-resident cardiac macrophage as well as macrophage polarization states. Dedicated balance between M1 and M2 cardiac macrophages are crucial for maintaining heart development and cardiac functional and electric homeostasis, and imbalance between macrophage phenotypes may result in heart ventricular remodeling and various heart diseases. The therapy aiming at specific target on macrophage phenotype is a promising strategy for treatment of heart diseases. In this article, we comprehensively review cardiac macrophage phenotype, metabolic reprogramming, and their role in maintaining heart health and mediating ventricular remodeling and potential therapeutic strategy in heart diseases.

Wharton's Jelly mesenchymal stem cell-derived extracellular vesicles induce liver fibrosis-resolving phenotype in alternatively activated macrophages

The potential of extracellular vesicles (EVs) isolated from mesenchymal stromal cells in guiding macrophages toward anti-inflammatory immunophenotypes, has been reported in several studies. In our study, we provided experimental evidence of a distinctive effect played by Wharton Jelly mesenchymal stromal cell-derived EVs (WJ-EVs) on human macrophages. We particularly analyzed their anti-inflammatory effects on macrophages by evaluating their interactions with stellate cells, and their protective role in liver fibrosis. A three-step gradient method was used to isolate monocytes from umbilical cord blood (UCB). Two subpopulations of WJ-EVs were isolated by high-speed (20,000 g) and differential ultracentrifugation (110,000 g). Further to their characterization, they were designated as EV20K and EV110K and incubated at different concentrations with UCB-derived monocytes for 7 days. Their anti-fibrotic effect was assessed by studying the differentiation and functional levels of generated macrophages and their potential to modulate the survival and activity of LX2 stellate cells. The EV20K triggers the polarization of UCB-derived monocytes towards a peculiar M2-like functional phenotype more effectively than the M-CSF positive control. The EV20K treated macrophages were characterized by a higher expression of scavenger receptors, increased phagocytic capacity and production level of interleukin-10 and transforming growth factor-β. Conditioned medium from those polarized macrophages attenuated the proliferation, contractility and activation of LX2 stellate cells. Our data show that EV20K derived from WJ-MSCs induces activated macrophages to suppress immune responses and potentially play a protective role in the pathogenesis of liver fibrosis by directly inhibiting HSC's activation.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

The effect of macrophages and their exosomes in ischemic heart disease

Ischemic heart disease (IHD) is a leading cause of disability and death worldwide, with immune regulation playing a crucial role in its pathogenesis. Various immune cells are involved, and as one of the key immune cells residing in the heart, macrophages play an indispensable role in the inflammatory and reparative processes during cardiac ischemia. Exosomes, extracellular vesicles containing lipids, nucleic acids, proteins, and other bioactive molecules, have emerged as important mediators in the regulatory functions of macrophages and hold promise as a novel therapeutic target for IHD. This review summarizes the regulatory mechanisms of different subsets of macrophages and their secreted exosomes during cardiac ischemia over the past five years. It also discusses the current status of clinical research utilizing macrophages and their exosomes, as well as strategies to enhance their therapeutic efficacy through biotechnology. The aim is to provide valuable insights for the treatment of IHD.

Excretory/secretory products from Trichinella spiralis adult worms ameliorate myocardial infarction by inducing M2 macrophage polarization in a mouse model

BACKGROUND

Ischemia-induced inflammatory response is the main pathological mechanism of myocardial infarction (MI)-caused heart tissue injury. It has been known that helminths and worm-derived proteins are capable of modulating host immune response to suppress excessive inflammation as a survival strategy. Excretory/secretory products from Trichinella spiralis adult worms (Ts-AES) have been shown to ameliorate inflammation-related diseases. In this study, Ts-AES were used to treat mice with MI to determine its therapeutic effect on reducing MI-induced heart inflammation and the immunological mechanism involved in the treatment.

METHODS

The MI model was established by the ligation of the left anterior descending coronary artery, followed by the treatment of Ts-AES by intraperitoneal injection. The therapeutic effect of Ts-AES on MI was evaluated by measuring the heart/body weight ratio, cardiac systolic and diastolic functions, histopathological change in affected heart tissue and observing the 28-day survival rate. The effect of Ts-AES on mouse macrophage polarization was determined by stimulating mouse bone marrow macrophages in vitro with Ts-AES, and the macrophage phenotype was determined by flow cytometry. The protective effect of Ts-AES-regulated macrophage polarization on hypoxic cardiomyocytes was determined by in vitro co-culturing Ts-AES-induced mouse bone marrow macrophages with hypoxic cardiomyocytes and cardiomyocyte apoptosis determined by flow cytometry.

RESULTS

We observed that treatment with Ts-AES significantly improved cardiac function and ventricular remodeling, reduced pathological damage and mortality in mice with MI, associated with decreased pro-inflammatory cytokine levels, increased regulatory cytokine expression and promoted macrophage polarization from M1 to M2 type in MI mice. Ts-AES-induced M2 macrophage polarization also reduced apoptosis of hypoxic cardiomyocytes in vitro.

CONCLUSIONS

Our results demonstrate that Ts-AES ameliorates MI in mice by promoting the polarization of macrophages toward the M2 type. Ts-AES is a potential pharmaceutical agent for the treatment of MI and other inflammation-related diseases.

Insights into the tumor-stromal-immune cell metabolism cross talk in ovarian cancer

The ovarian cancer tumor microenvironment (TME) consists of a constellation of abundant cellular components, extracellular matrix, and soluble factors. Soluble factors, such as cytokines, chemokines, structural proteins, extracellular vesicles, and metabolites, are critical means of noncontact cellular communication acting as messengers to convey pro- or antitumorigenic signals. Vast advancements have been made in our understanding of how cancer cells adapt their metabolism to meet environmental demands and utilize these adaptations to promote survival, metastasis, and therapeutic resistance. The stromal TME contribution to this metabolic rewiring has been relatively underexplored, particularly in ovarian cancer. Thus, metabolic activity alterations in the TME hold promise for further study and potential therapeutic exploitation. In this review, we focus on the cellular components of the TME with emphasis on 1) metabolic signatures of ovarian cancer; 2) understanding the stromal cell network and their metabolic cross talk with tumor cells; and 3) how stromal and tumor cell metabolites alter intratumoral immune cell metabolism and function. Together, these elements provide insight into the metabolic influence of the TME and emphasize the importance of understanding how metabolic performance drives cancer progression.

M1/M2 macrophages and their overlaps - myth or reality?

Macrophages represent heterogeneous cell population with important roles in defence mechanisms and in homoeostasis. Tissue macrophages from diverse anatomical locations adopt distinct activation states. M1 and M2 macrophages are two polarized forms of mononuclear phagocyte in vitro differentiation with distinct phenotypic patterns and functional properties, but in vivo, there is a wide range of different macrophage phenotypes in between depending on the microenvironment and natural signals they receive. In human infections, pathogens use different strategies to combat macrophages and these strategies include shaping the macrophage polarization towards one or another phenotype. Macrophages infiltrating the tumours can affect the patient's prognosis. M2 macrophages have been shown to promote tumour growth, while M1 macrophages provide both tumour-promoting and anti-tumour properties. In autoimmune diseases, both prolonged M1 activation, as well as altered M2 function can contribute to their onset and activity. In human atherosclerotic lesions, macrophages expressing both M1 and M2 profiles have been detected as one of the potential factors affecting occurrence of cardiovascular diseases. In allergic inflammation, T2 cytokines drive macrophage polarization towards M2 profiles, which promote airway inflammation and remodelling. M1 macrophages in transplantations seem to contribute to acute rejection, while M2 macrophages promote the fibrosis of the graft. The view of pro-inflammatory M1 macrophages and M2 macrophages suppressing inflammation seems to be an oversimplification because these cells exploit very high level of plasticity and represent a large scale of different immunophenotypes with overlapping properties. In this respect, it would be more precise to describe macrophages as M1-like and M2-like.

Immune cells drive new immunomodulatory therapies for myocardial infarction: From basic to clinical translation

The high incidence of heart failure secondary to myocardial infarction (MI) has been difficult to effectively address. MI causes strong aseptic inflammation, and infiltration of different immune cells and changes in the local inflammatory microenvironment play a key regulatory role in ventricular remodeling. Therefore, the possibility of improving the prognosis of MI through targeted immunity has been of interest and importance in MI. However, previously developed immune-targeted therapies have not achieved significant success in clinical trials. Here, we propose that the search for therapeutic targets from different immune cells may be more precise and lead to better clinical translation. Specifically, this review summarizes the role and potential therapeutic targets of various immune cells in ventricular remodeling after MI, especially monocytes/macrophages and neutrophils, as a way to demonstrate the importance and potential of immunomodulatory therapies for MI. In addition, we analyze the reasons for the failure of previous immunomodulatory therapies and the issues that need to be addressed, as well as the prospects and targeting strategies of using immune cells to drive novel immunomodulatory therapies, hoping to advance the development of immunomodulatory therapies by providing evidence and new ideas.

SARS-CoV-2 infection of phagocytic immune cells and COVID-19 pathology: Antibody-dependent as well as independent cell entry

Our review summarizes the evidence that COVID-19 can be complicated by SARS-CoV-2 infection of immune cells. This evidence is widespread and accumulating at an increasing rate. Research teams from around the world, studying primary and established cell cultures, animal models, and analyzing autopsy material from COVID-19 deceased patients, are seeing the same thing, namely that some immune cells are infected or capable of being infected with the virus. Human cells most vulnerable to infection include both professional phagocytes, such as monocytes, macrophages, and dendritic cells, as well as nonprofessional phagocytes, such as B-cells. Convincing evidence has accumulated to suggest that the virus can infect monocytes and macrophages, while data on infection of dendritic cells and B-cells are still scarce. Viral infection of immune cells can occur directly through cell receptors, but it can also be mediated or enhanced by antibodies through the Fc gamma receptors of phagocytic cells. Antibody-dependent enhancement (ADE) most likely occurs during the primary encounter with the pathogen through the first COVID-19 infection rather than during the second encounter, which is characteristic of ADE caused by other viruses. Highly fucosylated antibodies of vaccinees seems to be incapable of causing ADE, whereas afucosylated antibodies of persons with acute primary infection or convalescents are capable. SARS-CoV-2 entry into immune cells can lead to an abortive infection followed by host cell pyroptosis, and a massive inflammatory cascade. This scenario has the most experimental evidence. Other scenarios are also possible, for which the evidence base is not yet as extensive, namely productive infection of immune cells or trans-infection of other non-immune permissive cells. The chance of a latent infection cannot be ruled out either.