M2 Macrophage-Derived sEV Regulate Pro-Inflammatory CCR2+ Macrophage Subpopulations to Favor Post-AMI Cardiac Repair

Small extracellular vesicles from adipose derived stem cells alleviate microglia activation and improve motor deficit of Parkinson's disease via miR-100-5p/DTX3L/STAT1 signaling axis

Dopaminergic neuron loss caused by microglia activation is an important pathological factor of Parkinson's disease (PD). Previously, we reported that small extracellular vesicle from adipose derived stem cells (ADSC-sEVs) could inhibit the activation of microglia and protect neuron apoptosis from microglia activation. However, whether ADSC-sEVs have protective effect on the motor deficit of PD mouse and the exact mechanism remains unknown. In this study, ADSC-sEVs were delivered to experimental model of Parkinson's disease by tail vein injection to explore the in vivo effect of ADSC-sEVs on PD. Next, the potential key microRNA in ADSC-sEVs was screened by RNA sequencing (RNA-seq), and the exact mechanism was further explored. We found that ADSC-sEVs greatly alleviated the activation of microglia and reduced the loss of dopaminergic neurons in the substantia nigra of PD mice, the motor deficit was also significantly improved. By RNA-seq analysis, miR-100-5p was verified as a potential microRNA in this process, because knockdown of miR-100-5p in ADSC-sEVs weakened the protective effect of ADSC-sEVs on PD mouse as well as the anti-inflammatory effect on microglia activation. Finally, we found that miR-100-5p could target Deltex E3 ubiquitin ligase 3 L (DTX3L) and suppress its expression, which then decreased the expression and phosphorylation of Signal Transducers and Activators of Transcription 1 (STAT1), as well as alleviating the activation of microglia. Our findings illustrate that ADSC-sEVs are an effective therapy for PD, and it could be a promising therapy for the treatment of PD.

M2 macrophage derived exosomal miR-20a-5p ameliorates trophoblast pyroptosis and placental injuries in obstetric antiphospholipid syndrome via the TXNIP/NLRP3 axis

AIM

Obstetric antiphospholipid syndrome (OAPS) is a pregnancy-related complication characterized by trophoblast pyroptosis and placental injury induced by antiphospholipid antibodies (aPLs). M2-polarized macrophage-derived exosomes (M2-exos) exert anti-inflammatory, immunomodulatory, and growth-promoting effects in various autoimmune diseases and tumors. However, their role in OAPS is not yet clear. Therefore, in this study, we isolated M2-exos from M2 macrophages and investigated their effects on trophoblast proliferation, death, migration, invasion, and pyroptosis following stimulation using aPLs.

MAIN METHODS

First, we established an animal model of OAPS and thereafter treated the OAPS mice with exogenous M2-exos via injection through the tail vein. Then to clarify the roles of miR-20a-5p and thioredoxin-interacting protein (TXNIP) in OAPS, we performed gain- or loss-of-function assays, and used GraphPad Prism software to analyze the collected data with statistical significance set at P < 0.05.

KEY FINDINGS

MicroRNAs (miRNAs) sequencing revealed the enrichment of miR-20a-5p in M2-exos, and these M2-exos significantly alleviated aPLs-induced trophoblast dysfunction. Our results also indicated that M2-exos delivered miR-20a-5p to trophoblast cells directly targeted thioredoxin-interacting protein (TXNIP), and thus suppressed the TXNIP/NLRP3 pathway, reduced pyroptosis and inflammation in trophoblast cells, and improved placental function and fetal development.

SIGNIFICANCE

M2-exos improve pregnancy outcomes in OAPS via the miR-20a-5p/TXNIP/NLRP3 axis, and thus represent as a novel therapeutic approach for aPLs-induced OAPS.

Macrophage-Derived Extracellular Vesicles: A Novel Therapeutic Alternative for Diabetic Wound

Diabetic wounds represent a significant clinical and economic challenge owing to their chronicity and susceptibility to complications. Dysregulated macrophage function is a key factor in delayed wound healing. Recent studies have emphasized the therapeutic potential of macrophage-derived extracellular vesicles (MDEVs), which are enriched with bioactive molecules such as proteins, lipids, and nucleic acids that mirror the state of their parent cells. MDEVs influence immune modulation, angiogenesis, extracellular matrix remodeling, and intercellular communication. In this review, we summarize and discuss the biological properties and therapeutic mechanisms of MDEVs in diabetic wound healing, highlighting strategies to enhance their efficacy through bioengineering and advanced delivery systems. We also explore the integration of MDEVs into innovative wound care technologies. Addressing current limitations and advancing clinical translation of MDEVs could advance diabetic wound management, offering a precise, effective, and versatile therapeutic option.

Macrophage-driven exosomes regulate the progression of cardiovascular disease

Exosomes, as vital mediators of intercellular communication, play a critical role in the progression of cardiovascular disease (CVD). Recently, macrophage-derived exosomes (Mφ-Exos) have garnered increasing attention because of their significant potential in early diagnosis, pathological processes, and therapeutic applications for CVD. Exosomes contain diverse nucleic acids (e.g., miRNAs, mRNAs, and long noncoding RNAs (lncRNAs)) and proteins, which serve as specific biomarkers that regulate various stages of CVD. For example, miRNAs encapsulated within exosomes (e.g., miR-21, miR-133a, and miR-155) are closely associated with atherosclerosis, myocardial infarction, coronary artery disease, and stroke, and changes in their abundance can serve as diagnostic and prognostic indicators. Additionally, the composition of Mφ-Exos, including miRNAs, lipids, and proteins, plays a significant role in the initiation, progression, and inflammation of CVD. Research on Mφ-Exos provides new directions for early diagnosis, mechanistic exploration, and novel therapeutic targets in CVD. However, challenges remain regarding exosome isolation and identification technologies. Future studies need to further explore the biological properties of exosomes and develop more efficient, economical, and straightforward isolation methods. This review summarizes the multifaceted regulatory roles of Mφ-Exos in CVD, encompassing key processes such as inflammation, angiogenesis, metabolism, and cell death. Research has shown that M1-Exos promote the progression and exacerbation of CVD through pro-inflammatory and pro-fibrotic mechanisms, while M2-Exos demonstrate significant therapeutic potential via anti-inflammatory, pro-angiogenic, and metabolic reprogramming pathways. These findings not only reveal the complex mechanisms of Mφ-Exos in CVD but also provide new perspectives and potential targets for early diagnosis and precision treatment of the disease.

M2 Macrophage-Derived Extracellular Vesicles Reprogram Immature Neutrophils into Anxa1hi Neutrophils to Enhance Inflamed Bone Regeneration

Periodontitis is a microbiome-related inflammation that can lead to irreversible bone reduction and even tooth loss. This study reveals that macrophage polarization states significantly influence periodontal homeostasis, with M2 macrophage-derived extracellular vesicles (M2-EVs) playing a pivotal role in mitigating periodontitis-induced bone loss. Single-cell RNA sequencing of periodontal tissues treated with M2-EVs uncovered a unique Anxa1hi neutrophil subpopulation exhibiting pro-reparative properties. This subpopulation is characterized by immaturity and demonstrated osteogenic and angiogenic capabilities in vivo, partially mediated through the secretion of oncostatin M (OSM) signals. The findings suggest that this functional heterogeneity arises from M2-EVs disrupting the neutrophil maturation trajectory, with pivotal reprogramming genes, such as Acvrl1 and Fpr2, driving the differentiation of the Anxa1hi reparative subpopulation. This work underscores the potential of targeting M2 macrophage-neutrophil interactions to promote the regeneration of inflamed bone tissues.

Cardiac resident macrophages in cardiovascular disease: from physiology to pathology

Cardiovascular disease (CVD) is the leading cause of death and disease burden worldwide. Macrophages are important components of the internal immune cells, which profoundly affects the internal environmental homeostasis and repair after injury. Cardiac resident macrophages have been shown to regulate a variety of myocardial physiology and pathological activities. Homeostatic resident macrophages in the heart promote angiogenesis, remove ageing and dying cells and participate in cardiac electrical conduction. However, the role of cardiac resident macrophages is still not fully understood despite the growing attention they have received. This review provides an overview of macrophage biology and highlights prominent and emerging interrelationships and functions between cardiac resident macrophages and CVD, aiming to prove a description of the functional diversity of cardiac resident macrophages in different CVD to explore potential options to regulate them. This may provide opportunities for successful therapeutic interventions to improve the prognosis of patients with CVD.

Atomic Artificial Enzyme for Acute and Chronic Pneumonia

Pneumonia involves complex immunological and pathological processes leading to pulmonary dysfunction, which can be life-threatening yet lacks effective specialized medications. Natural enzymes can be used as biological agents for the treatment of oxidative stress-related diseases, but limiting to catalytic and environmental stability as well as high cost. Herein, an artificial enzyme, gold nanoclusters (Au NCs) with excellent stability, bioactivity, and renal clearance can be used as the next-generation biological agents for acute lung injury (ALI) and allergic lung disease (ALD). The Au25 clusters can mimic catalase (CAT) and glutathione peroxidase (GPx), and the Km of Au24Er1 with H2O2 reaches 1.28 mM, about 22 times higher than natural CAT (≈28.8 mM). The clusters inhibit the oxidative stress in the mitochondria and promote the synthesis of adenosine triphosphate (ATP). The molecular mechanism shows that the TLR4/MyD88/NF-κB pathway and M1 macrophage-mediated inflammatory response are suppressed in ALI and the Th1/Th2 imbalance in ovalbumin (OVA)-induced ALD is rescued. Further, the clusters can notably improve lung function in both ALI and ALD models which paves the way for immunomodulation and intervention for lung injury and can be used as a substitute for natural enzymes and potential biopharmaceuticals in the treatment of various types of pneumonia.

Dual-driven selenium Janus single-atom nanomotors for autonomous regulating mitochondrial oxygen imbalance to catalytic therapy of rheumatoid arthritis

O2 deficiency and excessive reactive oxygen and nitrogen species (RONS) in macrophage mitochondria is a key factor causing oxygen imbalance in rheumatoid arthritis microenvironment (RAM). Although nanocatalytic therapy that simultaneously produce O2 and eliminate RONS offer a novel strategy for RA therapy, the therapeutic efficacy of nanozymes is limited by the lack of autonomous targeting into mitochondria. Herein, we constructed a Janus-structured nanomotor (Pd@MSe) with autonomous targeting ability by embedding Pd single-atom nanozymes into mesoporous selenium (MSe) nanozymes, and obtained a composite nanomotor (Pd@MSe-TPP) with dual-driven forces by modifying with triphenylphosphine (TPP) in MSe hemisphere. In RAM, Pd@MSe-TPP nanomotor achieved autonomously target into macrophages mitochondria with the driven of generation O2 and TPP targeting effect, moreover under the single-atom effect of the Pd nanozymes enhanced electronic transfer between nanozymes, which significantly boosted GPx catalytic activity further effectively enhanced the diffusion of Pd@MSe-TPP nanomotor, thus quickly resorted the oxygen balance. Additionally, while regulating oxygen imbalance, Pd@MSe-TPP nanomotor enable rapidly blocked the inflammatory cascade, restored mitochondrial function and alleviated inflammation, further prevented cartilage degradation and effectively inhibited RA progression. Therefore, the exquisitely designed nanoplatform to regulation arthritic microenvironment provides a new direction for the RA therapy and the clinical translation of nanomedicine.

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Augmenting Antitumor Immune Effects through the Coactivation of cGAS-STING and NF-κB Crosstalk in Dendritic Cells and Macrophages by Engineered Manganese Ferrite Nanohybrids

The specific activation of dendritic cells (DCs) and tumor-associated macrophages (TAMs) can activate innate and adaptive immune responses to reverse the tumor immunosuppressive microenvironment. In this study, manganese ferrite nanohybrid MnFe5O8@(M1M-DOX) is synthesized to activate cGAS-STING and NF-κB crosstalk in DCs and TAMs. MnFe5O8, as the source of Fe2+/Fe3+ and Mn2+, is encapsulated with a microdose of doxorubicin (DOX) using an M1 macrophage cytomembrane. Fe2+/Fe3+ and DOX can cooperatively induce tumorous ferroptosis, triggering immunogenic cell death (ICD) that exposes tumor antigens. The release of Fe2+/Fe3+ and Mn2+ has intrinsic dual-immunomodulatory effects on the activation of DCs and the reprogramming of TAMs from the M2 to M1 phenotype. Briefly, Fe2+/Fe3+ activates the NF-κB signaling pathway to trigger the activation of STING signaling. Meanwhile, Mn2+ further enhances the activation of STING and stimulates NF-κB in a cascade-activating manner. Thus, the mutually reinforcing dual activation of cGAS-STING and NF-κB crosstalk prompts the strong maturation of DCs and TAMs, synergistically promoting the infiltration of T cells to inhibit primary tumor growth and localized recurrence. This work proposes a strategy for delivering immunomodulatory metal ions in nanoalloy and harnessing the activation of multisignaling pathways in antigen-presenting cells (APCs) to provide perspectives for tumor immunotherapy.

Anti-pyroptosis biomimetic nanoplatform loading puerarin for myocardial infarction repair: From drug discovery to drug delivery

Pyroptosis is a critical pathological mechanism implicated in myocardial damage following myocardial infarction (MI), and the crosstalk between macrophages and pyroptotic cardiomyocytes presents a formidable challenge for anti-pyroptosis therapies of MI. However, as single-target pyroptosis inhibitors frequently fail to address this crosstalk, the efficacy of anti-pyroptosis treatment post-MI remains inadequate. Therefore, the exploration of more potent anti-pyroptosis approaches is imperative for improving outcomes in MI treatment, particularly in addressing the crosstalk between macrophages and pyroptotic cardiomyocytes. Here, in response to this crosstalk, we engineered an anti-pyroptosis biomimetic nanoplatform (NM@PDA@PU), employing polydopamine (PDA) nanoparticles enveloped with neutrophil membrane (NM) for targeted delivery of puerarin (PU). Notably, network pharmacology is deployed to discern the most efficacious anti-pyroptosis drug (puerarin) among the 7 primary active monomers of TCM formulations widely applied in clinical practice and reveal the effect of puerarin on the crosstalk. Additionally, targeted delivery of puerarin could disrupt the malignant crosstalk between macrophages and pyroptotic cardiomyocytes, and enhance the effect of anti-pyroptosis by not only directly inhibiting cardiomyocytes pyroptosis through NLRP3-CASP1-IL-1β/IL-18 signal pathway, but reshaping the inflammatory microenvironment by reprogramming macrophages to anti-inflammatory M2 subtype. Overall, NM@PDA@PU could enhance anti-pyroptosis effect by disrupting the crosstalk between M1 macrophages and pyroptotic cardiomyocytes to protect cardiomyocytes, ameliorate cardiac function and improve ventricular remodeling, which providing new insights for the efficient treatment of MI.

Myocardia-Injected Synergistically Anti-Apoptotic and Anti-Inflammatory Poly(amino acid) Hydrogel Relieves Ischemia-Reperfusion Injury

Reperfusion therapy is the most effective treatment for acute myocardial infarction, but its efficacy is frequently limited by ischemia-reperfusion injury (IRI). While antioxidant and anti-inflammatory therapies have shown significant potential in alleviating IRI, these strategies have not yielded satisfactory clinical outcomes. For that, a thermo-sensitive myocardial-injectable poly(amino acid) hydrogel of methoxy poly(ethylene glycol)45-poly(L-methionine20-co-L-alanine10) (mPEG45-P(Met20-co-Ala10), PMA) loaded with FTY720 (PMA/FTY720) is developed to address IRI through synergistic anti-apoptotic and anti-inflammatory effects. Upon injection into the ischemic myocardium, the PMA aqueous solution undergoes a sol-to-gel phase transition and gradually degrades in response to reactive oxygen species (ROS), releasing FTY720 on demand. PMA acts synergistically with FTY720 to inhibit cardiomyocyte apoptosis and modulate pro-inflammatory M1 macrophage polarization toward anti-inflammatory M2 macrophages by clearing ROS, thereby mitigating the inflammatory response and promoting vascular regeneration. In a rat IRI model, PMA/FTY720 reduces the apoptotic cell ratio by 81.8%, increases vascular density by 34.0%, and enhances left ventricular ejection fraction (LVEF) by 12.8%. In a rabbit IRI model, the gel-based sustained release of FTY720 enhanced LVEF by an additional 7.2% compared to individual treatment. In summary, the engineered PMA hydrogel effectively alleviates IRI through synergistic anti-apoptosis and anti-inflammation actions, offering valuable clinical potential for treating myocardial IRI.

Exploration of M2 macrophage membrane as a biotherapeutic agent and strong synergistic therapeutic effects in ischemic stroke

The macrophage-derived membrane is widely applied in the targeting nanocarrier for its inflammatory tendency and long circulation ability due to the preservation of membrane protein. Few studies reported the application of macrophage membranes as biotherapeutic agents. To verify the ability of macrophage membrane as a biotherapeutic agent, ischemic stroke was selected as the model disease. Inspired by the features of macrophages infiltrating the ischemic core and the talent of M2 macrophages in modulating the inflammatory microenvironment, an M2 macrophage membrane (M2M)-disguised poly lactic-co-glycolic acid nanoparticles loaded with baicalin (BA) (M2M@BANPs) is developed. The results in vivo and in vitro indicate that M2M@BANPs could efficiently and actively target ischemic brain tissue and accumulate in microglia and neurons due to the coating of M2M. Furthermore, M2M and M2M@BANPs exhibit significant therapeutic effects in salvaging brain tissue damage and neurological functional recovery by reprogramming microglia from M1 to M2, reducing neutrophil infiltration and inhibiting neuronal apoptosis. Together, our fabrication provides a new insight and an applicative perspective for M2M in the therapy of ischemic stroke.

Harnessing Extracellular Vesicles for Stabilized and Functional IL-10 Delivery in Macrophage Immunomodulation

Extracellular vesicles (EVs) are gaining recognition as promising therapeutic carriers for immune modulation. We investigated the potential of EVs derived from HEK293FT cells to stabilize and deliver interleukin-10 (IL-10), a key anti-inflammatory cytokine. Using minicircle (MC) DNA vectors, we achieved IL-10 overexpression and efficient incorporation into EVs, yielding superior stability compared to free, recombinant IL-10 protein. Detailed biophysical and functional analyses revealed that IL-10+ EVs contain both monomeric and oligomeric forms of IL-10 on their external surface and encapsulated within vesicles. IL-10+ EVs suppressed inflammatory cytokine expression in pro-inflammatory macrophages (from two to 14-fold compared to naïve EVs) without inducing anti-inflammatory polarization, demonstrating a distinct immunosuppressive mechanism. Interestingly, naïve EVs from non-transfected cells also exhibited significant anti-inflammatory effects, suggesting that the intrinsic bioactive cargo of EVs substantially contributes to their function, complicating the interpretation of IL-10-specific effects. Size-based fractionation analyses of IL-10+ large EVs (lEVs), small EVs (sEVs), and non-vesicular extracellular particles (NVEPs) revealed IL-10 presence across all fractions, predominantly in monomeric form, with anti-inflammatory activity distributed among subpopulations. Anion exchange chromatography successfully enriched IL-10+ exosomes while retaining immunomodulatory effects. However, the shared properties of naïve and IL-10+ exosomes underscore the complexity of their immunomodulatory functions. These findings highlight the therapeutic potential of EVs while emphasizing the need to disentangle the contributions of engineered cytokines from endogenous vesicular components.

Macrophage-derived extracellular vesicles as new players in chronic non-communicable diseases

Macrophages are innate immune cells present in all tissues and play an important role in almost all aspects of the biology of living organisms. Extracellular vesicles (EVs) are released by cells and transport their contents (micro RNAs, mRNA, proteins, and long noncoding RNAs) to nearby or distant cells for cell-to-cell communication. Numerous studies have shown that macrophage-derived extracellular vesicles (M-EVs) and their contents play an important role in a variety of diseases and show great potential as biomarkers, therapeutics, and drug delivery vehicles for diseases. This article reviews the biological functions and mechanisms of M-EVs and their contents in chronic non-communicable diseases such as cardiovascular diseases, metabolic diseases, cancer, inflammatory diseases and bone-related diseases. In addition, the potential application of M-EVs as drug delivery systems for various diseases have been summarized.

Role of macrophage polarization in diabetic foot ulcer healing: A bibliometric study

BACKGROUND

Diabetic foot ulcers (DFUs) are a significant contributor to disability and mortality in diabetic patients. Macrophage polarization and functional regulation are promising areas of research and show therapeutic potential in the field of DFU healing. However, the complex mechanism, the difficulty in clinical translation, and the large heterogeneity present significant challenges. Hence, this study was to comprehensively analyze the publication status and trends of studies on macrophage polarization and DFU healing.

AIM

To examine the relevant literature on macrophage polarization in DFU healing.

METHODS

A bibliometric analysis was conducted using the Web of Science database. Relevant literature was retrieved from the Web of Science Core Collection database between 2013 to 2023 using literature visualization and analysis software (VOSviewer and CiteSpace) and bibliometric online platforms. The obtained literature was then subjected to visualization and analysis of different countries/regions, institutions, journals, authors, and keywords to reveal the research's major trends and focus.

RESULTS

The number of publications on the role of macrophage polarization in DFU healing increased rapidly from 2013 to 2023, especially in the latter period. Chinese researchers were the most prolific in this field, with 217 publications, while American researchers had been engaged in this field for a longer period. Qian Tan of Nanjing Drum Tower Hospital and Qian Ding of Nanjing University were the first to publish in this field. Shanghai Jiao Tong University was the institution with the most publications (27). The keywords "bone marrow", "adjustment, replacement, response, tissue repair", and "activation, repair, differentiation" appeared more frequently. The study of macrophage polarization in DFU healing focused on the regulatory mechanism, gene expression, and other aspects.

CONCLUSION

This study through the bibliometric method reveals the research trends and development trends in this field of macrophage polarization in DFU healing from 2013 to 2023 in the Web of Science Core Collection database. The key hotspots in this field mainly include the regulation of macrophage activation, gene expression, wound tissue repair, and new wound materials. This study provides references for future research directions.

Neonatal heart tissue-derived EVs alleviate adult ischemic cardiac injury via regulating the function of macrophages and cardiac regeneration in murine models

Previous studies confirmed the regenerative capacity of the mammalian neonatal heart. We recently found that adult heart tissue-derived EVs can protect the heart from myocardial ischemia-reperfusion (I/R). However, the role of EVs from neonatal heart tissue in cardiac healing post-ischemia remains unclear. In the present study, we revealed that intramyocardial administration of neonatal cardiac tissue-derived EVs (ncEVs) alleviated cardiac inflammation, mitigated reperfusion injury, and improved cardiac function in murine I/R models. In vitro, ncEVs inhibited M1 polarization of macrophages induced by LPS while up-regulated their phagocytic function via the miR-133a-3p-Ash1l signaling pathway. Moreover, the administration of ncEVs contributed to cardiac angiogenesis and improved cardiac function in murine myocardial infarction models. Collectively, these results suggested that neonatal heart-derived EVs can regulate the function of macrophages and contribute to cardiac regeneration and function recovery in murine cardiac ischemic models. Therefore, the derivatives in neonatal heart tissue-derived EVs might serve as a potential therapeutic strategy in ischemic diseases.

Reprogramming macrophage metabolism following myocardial infarction: A neglected piece of a therapeutic opportunity

Given the global prevalence of myocardial infarction (MI) as the leading cause of mortality, there is an urgent need to devise novel strategies that target reducing infarct size, accelerating cardiac tissue repair, and preventing detrimental left ventricular (LV) remodeling. Macrophages, as a predominant type of innate immune cells, undergo metabolic reprogramming following MI, resulting in alterations in function and phenotype that significantly impact the progression of MI size and LV remodeling. This article aimed to delineate the characteristics of macrophage metabolites during reprogramming in MI and elucidate their targets and functions in cardioprotection. Furthermore, we summarize the currently proposed regulatory mechanisms of macrophage metabolic reprogramming and identify the regulators derived from endogenous products and natural small molecules. Finally, we discussed the challenges of macrophage metabolic reprogramming in the treatment of MI, with the goal of inspiring further fundamental and clinical research into reprogramming macrophage metabolism and validating its potential therapeutic targets for MI.

Pathophysiology of Angiotensin II-Mediated Hypertension, Cardiac Hypertrophy, and Failure: A Perspective from Macrophages

Heart failure is a complex syndrome characterized by cardiac hypertrophy, fibrosis, and diastolic/systolic dysfunction. These changes share many pathological features with significant inflammatory responses in the myocardium. Among the various regulatory systems that impact on these heterogeneous pathological processes, angiotensin II (Ang II)-activated macrophages play a pivotal role in the induction of subcellular defects and cardiac adverse remodeling during the progression of heart failure. Ang II stimulates macrophages via its AT1 receptor to release oxygen-free radicals, cytokines, chemokines, and other inflammatory mediators in the myocardium, and upregulates the expression of integrin adhesion molecules on both monocytes and endothelial cells, leading to monocyte-endothelial cell-cell interactions. The transendothelial migration of monocyte-derived macrophages exerts significant biological effects on the proliferation of fibroblasts, deposition of extracellular matrix proteins, induction of perivascular/interstitial fibrosis, and development of hypertension, cardiac hypertrophy and heart failure. Inhibition of macrophage activation using Ang II AT1 receptor antagonist or depletion of macrophages from the peripheral circulation has shown significant inhibitory effects on Ang II-induced vascular and myocardial injury. The purpose of this review is to discuss the current understanding in Ang II-induced maladaptive cardiac remodeling and dysfunction, particularly focusing on molecular signaling pathways involved in macrophages-mediated hypertension, cardiac hypertrophy, fibrosis, and failure. In addition, the challenges remained in translating these findings to the treatment of heart failure patients are also addressed.

The immune regulatory role of exosomal miRNAs and their clinical application potential in heart failure

Heart failure (HF) is a complex and debilitating condition characterized by the heart's inability to pump blood effectively, leading to significant morbidity and mortality. The abnormality of immune response is a key factor in the progression of HF, contributing to adverse cardiac remodeling and dysfunction. Exosomal microRNAs (miRNAs) play a pivotal role in regulating gene expression and cellular function, which are integral to the crosstalk between cardiac and immune cells, influencing immune cell functions, such as macrophage polarization, T cell activity, and cytokine production, thereby modulating various pathological processes of HF, such as inflammation, fibrosis, and cardiac dysfunction. This review emphasizes the immune-regulatory role of exosomal miRNAs in HF and highlights their clinical potential as diagnostic biomarkers and therapeutic agents.

Engineered macrophages: an "Intelligent Repair" cellular machine for heart injury

Macrophages are crucial in the heart's development, function, and injury. As part of the innate immune system, they act as the first line of defense during cardiac injury and repair. After events such as myocardial infarction or myocarditis, numerous macrophages are recruited to the affected areas of the heart to clear dead cells and facilitate tissue repair. This review summarizes the roles of resident and recruited macrophages in developing cardiovascular diseases. We also describe how macrophage phenotypes dynamically change within the cardiovascular disease microenvironment, exhibiting distinct pro-inflammatory and anti-inflammatory functions. Recent studies reveal the values of targeting macrophages in cardiovascular diseases treatment and the novel bioengineering technologies facilitate engineered macrophages as a promising therapeutic strategy. Engineered macrophages have strong natural tropism and infiltration for cardiovascular diseases aiming to reduce inflammatory response, inhibit excessive fibrosis, restore heart function and promote heart regeneration. We also discuss recent studies highlighting therapeutic strategies and new approaches targeting engineered macrophages, which can aid in heart injury recovery.

Evaluating the Reparative Potential of Secretome from Patient-Derived Induced Pluripotent Stem Cells during Ischemia-Reperfusion Injury in Human Cardiomyocytes

During a heart attack, ischemia causes losses of billions of cells; this is especially concerning given the minimal regenerative capability of cardiomyocytes (CMs). Heart remuscularization utilizing stem cells has improved cardiac outcomes despite little cell engraftment, thereby shifting focus to cell-free therapies. Consequently, we chose induced pluripotent stem cells (iPSCs) given their pluripotent nature, efficacy in previous studies, and easy obtainability from minimally invasive techniques. Nonetheless, using iPSC secretome-based therapies for treating injured CMs in a clinical setting is ill-understood. We hypothesized that the iPSC secretome, regardless of donor health, would improve cardiovascular outcomes in the CM model of ischemia-reperfusion (IR) injury. Episomal-generated iPSCs from healthy and dilated cardiomyopathy (DCM) donors, passaged 6-10 times, underwent 24 h incubation in serum-free media. Protein content of the secretome was analyzed by mass spectroscopy and used to treat AC16 immortalized CMs during 5 h reperfusion following 24 h of hypoxia. IPSC-derived secretome content, independent of donor health status, had elevated expression of proteins involved in cell survival pathways. In IR conditions, iPSC-derived secretome increased cell survival as measured by metabolic activity (p < 0.05), cell viability (p < 0.001), and maladaptive cellular remodelling (p = 0.052). Healthy donor-derived secretome contained increased expression of proteins related to calcium contractility compared to DCM donors. Congruently, only healthy donor-derived secretomes improved CM intracellular calcium concentrations (p < 0.01). Heretofore, secretome studies mainly investigated differences relating to cell type rather than donor health. Our work suggests that healthy donors provide more efficacious iPSC-derived secretome compared to DCM donors in the context of IR injury in human CMs. These findings illustrate that the regenerative potential of the iPSC secretome varies due to donor-specific differences.

Polarization of Macrophages in Tumor Microenvironment Using High-Throughput Single-Cell Metabolomics

Macrophages consist of a heterogeneous population of functionally distinct cells that participate in many physiological and pathological processes. They exhibit prominent plasticity by changing their different functional phenotypes represented by proinflammatory (M1) and anti-inflammatory (M2) in response to different environmental stimuli. Emerging evidence illustrates the importance of intracellular metabolic pathways in macrophage polarizations and functions. In the tumor microenvironment (TME), macrophages tend to M2 polarization, which promotes tumor growth and leads to adverse physiological effects. Due to the lack of highly specific antigens in M1 and M2 macrophages, significant challenges present in isolating these subtypes from clinical samples or in vitro coculture models of tumor-immune cells. In reverse, the single-cell technique provides the possibility to investigate the factors influencing macrophage polarization in the TME. In this research, we employed inertial microfluidic chip-mass spectrometry (IMC-MS) to conduct single-cell metabolomics analysis of macrophages polarized into the two major phenotypes, respectively, and 213 metabolites were identified in total. Subsequently, differential metabolites between macrophage phenotypes were analyzed using volcano plots and binary logistic regression models. Glutamine was pinpointed as a key metabolite for the M1 and M2 phenotypes. Experimental results from both monoculture and coculture cell models demonstrated that M1 polarization is more reliant on the presence of glutamine in the culture environment than M2 polarization. Glutamine deficiency resulted in failed M1 polarization, while its absence had a less pronounced effect on M2 polarization. Replenishing an appropriate amount of glutamine during the intermediate stages of coculture models significantly enhanced the proportion of M1 polarization and suppressed the growth of tumor cells. This research elucidated glutamine as a key factor influencing macrophage polarization in the TME via single-cell metabolomics based on IMC-MS, offering promising insights and targets for tumor therapies.

Bioderived Nanoparticles for Cardiac Repair

Biobased therapy represents a promising strategy for myocardial repair. However, the limitations of using live cells, including the risk of immunogenicity of allogeneic cells and inconsistent therapeutic efficacy of autologous cells together with low stability, result in an unsatisfactory clinical outcomes. Therefore, cell-free strategies for cardiac tissue repair have been proposed as alternative strategies. Cell-free strategies, primarily based on the paracrine effects of cellular therapy, have demonstrated their potential to inhibit apoptosis, reduce inflammation, and promote on-site cell migration and proliferation, as well as angiogenesis, after an infarction and have been explored preclinically and clinically. Among various cell-free modalities, bioderived nanoparticles, including adeno-associated virus (AAV), extracellular vesicles, cell membrane-coated nanoparticles, and exosome-mimetic nanovesicles, have emerged as promising strategies due to their improved biological function and therapeutic effect. The main focus of this review is the development of existing cellular nanoparticles and their fundamental working mechanisms, as well as the challenges and opportunities. The key processes and requirements for cardiac tissue repair are summarized first. Various cellular nanoparticle modalities are further highlighted, together with their advantages and limitations. Finally, we discuss various delivery approaches that offer potential pathways for researchers and clinicians to translate cell-free strategies for cardiac tissue repair into clinical practice.

Reactive oxide species and ultrasound dual-responsive bilayer microneedle array for in-situ sequential therapy of acute myocardial infarction

Acute myocardial infarction (AMI) resulting from coronary artery occlusion stands as the predominant cause of cardiovascular disability and mortality worldwide. An all-encompassing treatment strategy targeting pathological processes of oxidative stress, inflammation, proliferation and fibrotic remodeling post-AMI is anticipated to enhance therapeutic outcomes. Herein, an up-down-structured bilayer microneedle (Ce-CLMs-BMN) with reactive oxygen species (ROS) and ultrasound (US) dual-responsiveness is proposed for AMI in-situ sequential therapy. The upper-layer microneedle is formulated by crosslinking ROS-sensitive linker with polyvinyl alcohol loaded with cerium dioxide nanoparticles (CeNPs) featuring versatile enzyme-mimetic activities. During AMI acute phase, prompted by ischemia-induced microenvironmental redox imbalance, this layer swiftly releases CeNPs, which aid in eliminating excessive ROS and catalyzing oxygen gas (O2) production through multiple enzymatic pathways, thereby alleviating oxidative stress-induced damage and modulating inflammation. In AMI chronic repair phase, micro-nano reactors (CLMs) situated in the lower-layer microneedle undergo cascade reactions with the assistance of US irradiation to generate nitric oxide (NO). As a bioactive molecule with pro-angiogenic and anti-fibrotic effects, NO expedites cardiac repair while attenuating adverse remodeling. Additionally, its antiplatelet-aggregating properties contribute to thromboprophylaxis. In-vitro and in-vivo results substantiate the efficacy of this integrated healing approach in AMI management, showcasing promising prospects for advancing infarcted heart repair.

The immunomodulatory of interleukin-33 in rheumatoid arthritis: A systematic review

Rheumatoid arthritis (RA) is a systemic chronic autoimmune disease that primarily affects the joints and surrounding soft tissues, characterized by chronic inflammation and proliferation of the synovium. Various immune cells are involved in the pathophysiology of RA. The complex interplay of factors such as chronic inflammation, genetic susceptibility, dysregulation of serum antibody levels, among others, contribute to the complexity of the disease mechanism, disease activity, and treatment of RA. Recently, the cytokine storm leading to increased disease activity in RA has gained significant attention. Interleukin-33 (IL-33), a member of the IL-1 family, plays a crucial role in inflammation and immune regulation. ST2 (suppression of tumorigenicity 2 receptor), the receptor for IL-33, is widely expressed on the surface of various immune cells. When IL-33 binds to its receptor ST2, it activates downstream signaling pathways to exert immunoregulatory effects. In RA, IL-33 regulates the progression of the disease by modulating immune cells such as circulating monocytes, tissue-resident macrophages, synovial fibroblasts, mast cells, dendritic cells, neutrophils, T cells, B cells, endothelial cells, and others. We have summarized and analyzed these findings to elucidate the pathways through which IL-33 regulates RA. Furthermore, IL-33 has been detected in the synovium, serum, and synovial fluid of RA patients. Due to inconsistent research results, we conducted a meta-analysis on the association between serum IL-33, synovial fluid IL-33, and the risk of developing RA in patients. The pooled SMD was 1.29 (95% CI: 1.15-1.44), indicating that IL-33 promotes the onset and pathophysiological progression of RA. Therefore, IL-33 may serve as a biomarker for predicting the risk of developing RA and treatment outcomes. As existing drugs for RA still cannot address drug resistance in some patients, new therapeutic approaches are needed to alleviate the significant burden on RA patients and healthcare systems. In light of this, we analyzed the potential of targeting the IL-33/ST2-related signaling pathway to modulate immune cells associated with RA and alleviate inflammation. We also reviewed IL-33 and RA susceptibility-related single nucleotide polymorphisms, suggesting potential involvement of IL-33 and macrophage-related drug-resistant genes in RA resistance therapy. Our review elucidates the role of IL-33 in the pathophysiology of RA, offering new insights for the treatment of RA.

IL-1 signaling pathway, an important target for inflammation surrounding in myocardial infarction

Acute myocardial infarction is an important cardiovascular disease worldwide. Although the mortality rate of myocardial infarction (MI) has improved dramatically in recent years due to timely treatment, adverse remodeling of the left ventricle continues to affect cardiac function. Various immune cells are involved in this process to induce inflammation and amplification. The infiltration of inflammatory cells in the infarcted myocardium is induced by various cytokines and chemokines, and the recruitment of leukocytes further amplifies the inflammatory response. As an increasing number of clinical anti-inflammatory therapies have achieved significant success in recent years, treating myocardial infarction by targeting inflammation may become a novel therapeutic option. In particular, successful clinical trials of canakinumab have demonstrated the important role of the inflammatory factor interleukin-1 (IL-1) in atherosclerosis. Targeted IL-1 therapy may decrease inflammation levels and improve cardiac function in patients after myocardial infarction. This article reviews the complex series of responses after myocardial infarction, including the involvement of inflammatory cells and the role of cytokines and chemokines, focusing on the progression of the IL-1 family in myocardial infarction as well as the performance of current targeted therapy drugs in experiments.

Self-Adapting Biomass Hydrogel Embodied with miRNA Immunoregulation and Long-Term Bacterial Eradiation for Synergistic Chronic Wound Therapy

Chronic wound rescue is critical for diabetic patients but is challenging to achieve with a specific and long-term strategy. The prolonged bacterial inflammation is particularly prevalent in hyperglycemia-induced wounds, usually leading to severe tissue damage. Such a trend could further suffer from an environmental suitability provided by macrophages for persisting Staphylococcus aureus (S. aureus) and even deteriorate by their mutual reinforcement. However, the strategy of both suppressing bacteria growth and immunoreprogramming the inflammatory type of macrophages to break their vicious harm to wound healing is still lacking. Here, a self-adapting biomass carboxymethyl chitosan (CMC) hydrogel comprising immunomodulatory nanoparticles is reported to achieve Gram-negative/Gram-positive bacteria elimination and anti-inflammatory cytokines induction to ameliorate the cutaneous microenvironment. Mechanistically, antibacterial peptides and CMCs synergistically result in a long-term inhibition against methicillin-resistant S. aureus (MRSA) over a period of 7 days, and miR-301a reprograms the M2 macrophage via the PTEN/PI3Kγ/mTOR signaling pathway, consequently mitigating inflammation and promoting angiogenesis for diabetic wound healing in rats. In this vein, immunoregulatory hydrogel is a promising all-biomass dressing ensuring biocompatibility, providing a perspective to regenerate cutaneous damaged tissue, and repairing chronic wounds on skin.

The role and research progress of macrophages after heart transplantation

Since the 60s of the 20th century, heart transplantation has been the best treatment for patients with end-stage heart failure. Due to the increasing number of patients, how to expand the number of donor organs and enhance immune compatibility has become an urgent problem to be solved at this stage. Although current immunosuppression is effective, its side effects are also quite obvious, such as opportunistic infections and malignant tumors. In this review, we focus on the important role in macrophages after heart transplantation and their potential targets for achieving allogeneic graft tolerance, in order to improve effective graft survival and reduce infection and the occurrence of malignant tumors.

Decoding cellular plasticity and niche regulation of limbal stem cells during corneal wound healing

BACKGROUND

Dysfunction or deficiency of corneal epithelium results in vision impairment or blindness in severe cases. The rapid and effective regeneration of corneal epithelial cells relies on the limbal stem cells (LSCs). However, the molecular and functional responses of LSCs and their niche cells to injury remain elusive.

METHODS

Single-cell RNA sequencing was performed on corneal tissues from normal mice and corneal epithelium defect models. Bioinformatics analysis was performed to confirm the distinct characteristics and cell fates of LSCs. Knockdown of Creb5 and OSM treatment experiment were performed to determine their roles of in corneal epithelial wound healing.

RESULTS

Our data defined the molecular signatures of LSCs and reconstructed the pseudotime trajectory of corneal epithelial cells. Gene network analyses characterized transcriptional landmarks that potentially regulate LSC dynamics, and identified a transcription factor Creb5, that was expressed in LSCs and significantly upregulated after injury. Loss-of-function experiments revealed that silencing Creb5 delayed the corneal epithelial healing and LSC mobilization. Through cell-cell communication analysis, we identified 609 candidate regeneration-associated ligand-receptor interaction pairs between LSCs and distinct niche cells, and discovered a unique subset of Arg1+ macrophages infiltrated after injury, which were present as the source of Oncostatin M (OSM), an IL-6 family cytokine, that were demonstrated to effectively accelerate the corneal epithelial wound healing.

CONCLUSIONS

This research provides a valuable single-cell resource and reference for the discovery of mechanisms and potential clinical interventions aimed at ocular surface reconstruction.

Modulation of cardiac resident macrophages immunometabolism upon high-fat-diet feeding in mice

Background

A high-fat diet (HFD) contributes to various metabolic disorders and obesity, which are major contributors to cardiovascular disease. As an essential regulator for heart homeostasis, cardiac resident macrophages may go awry and contribute to cardiac pathophysiology upon HFD. Thus, to better understand how HFD induced cardiac dysfunction, this study intends to explore the transcriptional and functional changes in cardiac resident macrophages of HFD mice.

Methods

C57BL/6J female mice that were 6 weeks old were fed with HFD or normal chow diet (NCD) for 16 weeks. After an evaluation of cardiac functions by echocardiography, mouse hearts were harvested and cardiac resident CCR2- macrophages were sorted, followed by Smart sequencing. Bioinformatics analysis including GO, KEGG, and GSEA analyses were employed to elucidate transcriptional and functional changes.

Results

Hyperlipidemia and obesity were observed easily upon HFD. The mouse hearts also displayed more severe fibrosis and diastolic dysfunction in HFD mice. Smart sequencing and functional analysis revealed metabolic dysfunctions, especially lipid-related genes and pathways. Besides this, antigen-presentation-related gene such as Ctsf and inflammation, particularly for NF-κB signaling and complement cascades, underwent drastic changes in cardiac resident macrophages. GO cellular compartment analysis was also performed and showed specific organelle enrichment trends of the involved genes.

Conclusion

Dysregulated metabolism intertwines with inflammation in cardiac resident macrophages upon HFD feeding in mice, and further research on crosstalk among organelles could shed more light on potential mechanisms.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

Deciphering the Enigma of Intramyocardial Hemorrhage Following Reperfusion Therapy in Acute ST-Segment Elevation Myocardial Infarction: A Comprehensive Exploration from Mechanisms to Therapeutic Strategies

Acute ST-segment elevation myocardial infarction (STEMI) is a formidable challenge in cardiovascular medicine, demanding advanced reperfusion strategies such as emergency percutaneous coronary intervention. While successful revascularization is pivotal, the persistent "no-reflow" phenomenon remains a clinical hurdle, often intertwined with microvascular dysfunction. Within this intricate scenario, the emergence of intramyocardial hemorrhage (IMH) has garnered attention as a significant contributor. This review offers a detailed exploration of the multifaceted relationship between IMH and the "no-reflow" phenomenon, delving into the mechanisms governing IMH occurrence, state-of-the-art diagnostic modalities, predictive factors, clinical implications, and the evolving landscape of preventive and therapeutic strategies. The nuanced examination aims to deepen our comprehension of IMH, providing a foundation for the identification of innovative therapeutic avenues and enhanced clinical outcomes for STEMI patients.

Fenofibrate Induces a Resolving Profile in Heart Macrophage Subsets and Attenuates Acute Chagas Myocarditis

Chagas disease, caused by Trypanosoma cruzi, stands as the primary cause of dilated cardiomyopathy in the Americas. Macrophages play a crucial role in the heart's response to infection. Given their functional and phenotypic adaptability, manipulating specific macrophage subsets could be vital in aiding essential cardiovascular functions including tissue repair and defense against infection. PPARα are ligand-dependent transcription factors involved in lipid metabolism and inflammation regulation. However, the role of fenofibrate, a PPARα ligand, in the activation profile of cardiac macrophages as well as its effect on the early inflammatory and fibrotic response in the heart remains unexplored. The present study demonstrates that fenofibrate significantly reduces not only the serum activity of tissue damage biomarker enzymes (LDH and GOT) but also the circulating proportions of pro-inflammatory monocytes (CD11b+ LY6Chigh). Furthermore, both CD11b+ Ly6Clow F4/80high macrophages (MΦ) and recently differentiated CD11b+ Ly6Chigh F4/80high monocyte-derived macrophages (MdMΦ) shift toward a resolving phenotype (CD206high) in the hearts of fenofibrate-treated mice. This shift correlates with a reduction in fibrosis, inflammation, and restoration of ventricular function in the early stages of Chagas disease. These findings encourage the repositioning of fenofibrate as a potential ancillary immunotherapy adjunct to antiparasitic drugs, addressing inflammation to mitigate Chagas disease symptoms.

CCR2 antagonist attenuates calcium oxalate-induced kidney oxidative stress and inflammation by regulating macrophage activation

C-C chemokine receptor type 2 (CCR2) is a monocyte chemokine associated with oxidative stress and inflammation. Kidney stones (KS) are composed of calcium oxalate (CaOx), which trigger renal oxidative stress and inflammatory. This study aims to evaluate the effects of CCR2 on KS in vivo and in vitro. Eight-week-old male C57BL/6J mice were intraperitoneally injected with glyoxylate (GOX) daily to establish a KS model, and along with CCR2 antagonist (INCB3344) treatment on days 2, 4, and 6. The results showed that CCR2 antagonist reduced renal injury markers (blood urea nitrogen and serum creatinine), alleviated renal tubular injury and CaOx crystal deposition. CCR2 antagonist also decreased CCR2 expression induced by GOX treatment and increased Nrf2 expression. GOX treatment promoted malondialdehyde (MDA) production, decreased glutathione (GSH) content, and inhibited catalase (CAT) and superoxide dismutase (SOD) activity, however, CCR2 antagonist attenuated the above effects of GOX. CCR2 antagonist had inhibitory effects on GOX-induced inflammatory cytokine expression (IL1B, IL6 and MCP1), and inhibited apoptosis by increasing Bcl-2 expression and decreasing Bax and cleaved-caspase 3 expression. In vitro experiments were performed by co-culture model of CaOx-induced damaged HK-2 cells and macrophage-like THP-1 cells. CCR2 antagonist inhibited CaOx-induced THP-1 cell M1 polarization by decreasing the TNF-α, IL6 and iNOS levels, and further alleviated CaOx-induced oxidative stress damage, inflammatory response and apoptosis of HK-2 cells. The study suggests that CCR2 antagonist may be resistant to CaOx crystals-induced oxidative stress and inflammation by inhibiting macrophage M1 polarization.

Engineered M2 macrophage-derived extracellular vesicles with platelet membrane fusion for targeted therapy of atherosclerosis

Atherosclerosis is featured as chronic low-grade inflammation in the arteries, which leads to the formation of plaques rich in lipids. M2 macrophage-derived extracellular vesicles (M2EV) have significant potential for anti-atherosclerotic therapy. However, their therapeutic effectiveness has been hindered by their limited targeting capability in vivo. The objective of this study was to create the P-M2EV (platelet membrane-modified M2EV) using the membrane fusion technique in order to imitate the interaction between platelets and macrophages. P-M2EV exhibited excellent physicochemical properties, and microRNA (miRNA)-sequencing revealed that the extrusion process had no detrimental effects on miRNAs carried by the nanocarriers. Remarkably, miR-99a-5p was identified as the miRNA with the highest expression level, which targeted the mRNA of Homeobox A1 (HOXA1) and effectively suppressed the formation of foam cells in vitro. In an atherosclerotic low-density lipoprotein receptor-deficient (Ldlr-/-) mouse model, the intravenous injection of P-M2EV showed enhanced targeting and greater infiltration into atherosclerotic plaques compared to regular extracellular vesicles. Crucially, P-M2EV successfully suppressed the progression of atherosclerosis without causing systemic toxicity. The findings demonstrated a biomimetic platelet-mimic system that holds great promise for the treatment of atherosclerosis in clinical settings.

A paintable and adhesive hydrogel cardiac patch with sustained release of ANGPTL4 for infarcted heart repair

The infarcted heart undergoes irreversible pathological remodeling after reperfusion involving left ventricle dilation and excessive inflammatory reactions in the infarcted heart, frequently leading to fatal functional damage. Extensive attempts have been made to attenuate pathological remodeling in infarcted hearts using cardiac patches and anti-inflammatory drug delivery. In this study, we developed a paintable and adhesive hydrogel patch using dextran-aldehyde (dex-ald) and gelatin, incorporating the anti-inflammatory protein, ANGPTL4, into the hydrogel for sustained release directly to the infarcted heart to alleviate inflammation. We optimized the material composition, including polymer concentration and molecular weight, to achieve a paintable, adhesive hydrogel using 10% gelatin and 5% dex-ald, which displayed in-situ gel formation within 135 s, cardiac tissue-like modulus (40.5 kPa), suitable tissue adhesiveness (4.3 kPa), and excellent mechanical stability. ANGPTL4 was continuously released from the gelatin/dex-ald hydrogel without substantial burst release. The gelatin/dex-ald hydrogel could be conveniently painted onto the beating heart and degraded in vivo. Moreover, in vivo studies using animal models of acute myocardial infarction revealed that our hydrogel cardiac patch containing ANGPTL4 significantly improved heart tissue repair, evaluated by echocardiography and histological evaluation. The heart tissues treated with ANGPTL4-loaded hydrogel patches exhibited increased vascularization, reduced inflammatory macrophages, and structural maturation of cardiac cells. Our novel hydrogel system, which allows for facile paintability, appropriate tissue adhesiveness, and sustained release of anti-inflammatory drugs, will serve as an effective platform for the repair of various tissues, including heart, muscle, and cartilage.

Mesenchymal Stem Cell Transplantation: Neuroprotection and Nerve Regeneration After Spinal Cord Injury

Spinal Cord Injury (SCI), with its morbidity characteristics of high disability rate and high mortality rate, is a disease that is highly destructive to both the physiology and psychology of the patient, and for which there is still a lack of effective treatment. Following spinal cord injury, a cascade of secondary injury reactions known as ischemia, peripheral inflammatory cell infiltration, oxidative stress, etc. create a microenvironment that is unfavorable to neural recovery and ultimately results in apoptosis and necrosis of neurons and glial cells. Mesenchymal stem cell (MSC) transplantation has emerged as a more promising therapeutic options in recent years. MSC can promote spinal cord injury repair through a variety of mechanisms, including immunomodulation, neuroprotection, and nerve regeneration, giving patients with spinal cord injury hope. In this paper, it is discussed the neuroprotection and nerve regeneration components of MSCs' therapeutic method for treating spinal cord injuries.

Macrophage-driven cardiac inflammation and healing: insights from homeostasis and myocardial infarction

Early and prompt reperfusion therapy has markedly improved the survival rates among patients enduring myocardial infarction (MI). Nonetheless, the resulting adverse remodeling and the subsequent onset of heart failure remain formidable clinical management challenges and represent a primary cause of disability in MI patients worldwide. Macrophages play a crucial role in immune system regulation and wield a profound influence over the inflammatory repair process following MI, thereby dictating the degree of myocardial injury and the subsequent pathological remodeling. Despite numerous previous biological studies that established the classical polarization model for macrophages, classifying them as either M1 pro-inflammatory or M2 pro-reparative macrophages, this simplistic categorization falls short of meeting the precision medicine standards, hindering the translational advancement of clinical research. Recently, advances in single-cell sequencing technology have facilitated a more profound exploration of macrophage heterogeneity and plasticity, opening avenues for the development of targeted interventions to address macrophage-related factors in the aftermath of MI. In this review, we provide a summary of macrophage origins, tissue distribution, classification, and surface markers. Furthermore, we delve into the multifaceted roles of macrophages in maintaining cardiac homeostasis and regulating inflammation during the post-MI period.

Extracellular Vesicles from Immune Cells: A Biomedical Perspective

Research on the role of extracellular vesicles (sEV) in physiology has demonstrated their undoubted importance in processes such as the transportation of molecules with significance for cell metabolism, cell communication, and the regulation of mechanisms such as cell differentiation, inflammation, and immunity. Although the role of EVs in the immune response is actively investigated, there is little literature revising, in a comprehensive manner, the role of small EVs produced by immune cells. Here, we present a review of studies reporting the release of sEV by different types of leukocytes and the implications of such observations on cellular homeostasis. We also discuss the function of immune cell-derived sEV and their relationship with pathological states, highlighting their potential application in the biomedical field.

Melatonin Engineering M2 Macrophage-Derived Exosomes Mediate Endoplasmic Reticulum Stress and Immune Reprogramming for Periodontitis Therapy

Periodontitis is a chronic infectious disease caused by bacterial irritation. As an essential component of the host immunity, macrophages are highly plastic and play a crucial role in inflammatory response. An appropriate and timely transition from proinflammatory (M1) to anti-inflammatory (M2) macrophages is indispensable for treating periodontitis. As M2 macrophage-derived exosomes (M2-exos) can actively target inflammatory sites and modulate immune microenvironments, M2-exos can effectively treat periodontitis. Excessive endoplasmic reticulum stress (ER stress) and unfolded protein response (UPR) are highly destructive pathological characteristics during inflammatory periodontal bone loss. Although melatonin has antioxidant and anti-inflammatory effects, studies focusing on melatonin ER stress modulation remain limited. This study fabricates engineered M2-exos loading with melatonin (Mel@M2-exos) for treating periodontitis. As a result, M2-exos drive an appropriate and timely macrophage reprogramming from M1 to M2 type, which resolves chronic inflammation and accelerated periodontal healing. Melatonin released from Mel@M2-exos rescues the osteogenic and cementogenic differentiation capacity in inflammatory human periodontal ligament cells (hPDLCs) by reducing excessive ER stress and UPR. Injectable gelatin methacryloyl (GelMA) hydrogels with sustained-release Mel@M2-exos accelerate periodontal bone regeneration in rats with ligation-induced periodontitis. Taken together, melatonin engineering M2 macrophage-derived exosomes are promising candidates for inflammatory periodontal tissue regeneration.

Biologic Mechanisms of Macrophage Phenotypes Responding to Infection and the Novel Therapies to Moderate Inflammation

Pro-inflammatory and anti-inflammatory types are the main phenotypes of the macrophage, which are commonly notified as M1 and M2, respectively. The alteration of macrophage phenotypes and the progression of inflammation are intimately associated; both phenotypes usually coexist throughout the whole inflammation stage, involving the transduction of intracellular signals and the secretion of extracellular cytokines. This paper aims to address the interaction of macrophages and surrounding cells and tissues with inflammation-related diseases and clarify the crosstalk of signal pathways relevant to the phenotypic metamorphosis of macrophages. On these bases, some novel therapeutic methods are proposed for regulating inflammation through monitoring the transition of macrophage phenotypes so as to prevent the negative effects of antibiotic drugs utilized in the long term in the clinic. This information will be quite beneficial for the diagnosis and treatment of inflammation-related diseases like pneumonia and other disorders involving macrophages.