Macrophage phenotypes in atherosclerosis

Dual-targeted microbubbles for atherosclerosis therapy: Inducing M1 macrophage apoptosis by inhibiting telomerase activity

The progression of atherosclerosis (AS) is closely associated with M1 macrophages. Although the activation of macrophage telomerase during plaque formation has been documented, targeted modulation strategies remain challenging. In this study, we developed a dual-target microbubble-delivery system (Ab-MMB1532) encapsulating BIBR1532, a telomerase inhibitor, for the targeted therapy of AS. This system exhibited remarkable targeting capabilities towards M1 macrophages, with its targeting advantage notably accentuated under high shear forces. Mechanistically, Ab-MMB1532 inhibited telomerase activity by downregulating telomerase reverse transcriptase (TERT) expression, subsequently inducing caspase-3-mediated apoptosis. Integrated multi-omics profiling revealed that the inhibition of the NF-κB pathway served as the central regulatory hub. In vivo studies further confirmed that Ab-MMB1532 effectively targets and accumulates within AS lesions, promoting M1 macrophage apoptosis through the inhibition of the TERT/NF-κB signaling axis, and significantly reducing plaque burden (25.4 % reduction vs. controls, p < 0.001). In summary, our findings suggest a novel approach for telomerase-targeted therapy in AS.

Immune Checkpoint Inhibitors and Immunosuppressive Tumor Microenvironment: Current Challenges and Strategies to Overcome Resistance

Immune checkpoint inhibitors (ICIs) are shown to improve cancer treatment effectiveness by boosting the immune system of the patient. Nevertheless, the unique and highly suppressive TME poses a significant challenge, causing heterogeneity of response or resistance in a considerable number of patients. This review focuses on the evasive attributes of the TME. Immune evasion mechanism in TME include immunosuppressive cells, cytokine and chemokine signaling, metabolic alterations and overexpression of immune checkpoint molecules such as PD-1, CTLA-4, LAG-3, TIM-3, TIGIT, BTLA and their interactions within the TME. In addition, this review focuses on the overcoming resistance by targeting immunosuppressive cells, normalizing tumor blood vessels, blocking two or three checkpoints simultaneously, combining vaccines, oncolytic viruses and metabolic inhibitors with ICIs or other therapies. This review also focuses on the necessity of finding predictive markers for the stratification of patients and to check response of ICIs treatment. It remains to be made certain by new research and intelligent innovations how these discoveries of the TME and its interplay facilitate ICI treatment and change the face of cancer treatment.

Advancements in the study of short-chain fatty acids and their therapeutic effects on atherosclerosis

Atherosclerosis (AS) remains a leading cause of cardiovascular disease and mortality globally. This chronic condition is characterized by inflammation, lipid accumulation, and the deposition of cellular components within arterial walls. Emerging evidence has highlighted the multifaceted therapeutic potential of short-chain fatty acids (SCFAs) in mitigating AS progression. SCFAs have demonstrated anti-inflammatory properties and the ability to regulate immune responses, metabolic pathways, vascular integrity, and intestinal barrier function in animal models of AS. Consequently, SCFAs have garnered significant attention as a promising approach for the prevention and treatment of AS. However, further clinical trials and studies are necessary to fully elucidate the underlying mechanisms and effects of SCFAs. Additionally, different types of SCFAs may exert distinct impacts, necessitating more in-depth investigation into their specific roles and mechanisms. This review provides an overview of the diverse cellular mechanisms contributing to AS formation, as well as a discussion of the significance of SCFAs in AS pathogenesis and their multifaceted therapeutic potential. Nonetheless, additional research is warranted to comprehensively understand and harness the potential of various SCFAs in the context of AS.

Iron-dependent lysosomal LDL oxidation induces the expression of scavenger receptor A in human THP-1 monocytes

Atherosclerosis leading to cardiovascular diseases remains a dominant medical problem. In the early stages of this disease, the interaction between circulating monocytes and the endothelium is crucial. Monocytes and macrophages express scavenger receptor A (SR-A), which mediates cell adhesion and subsequently uptake of oxidized low-density lipoproteins (LDL). High iron stores in monocytes or macrophages are known to predispose individuals to atherosclerosis, however the reasons remain poorly understood. We hypothesized that a combination of iron and LDL may induce proatherogenic changes in circulating monocytes. Here, we treated a human monocytic cell line THP-1 with isolated LDL and/or iron. A limited uptake of native LDL, but not iron or oxidized LDL, markedly induced expression of SR-A in these cells. Both SR-AI and SR-AII isoforms were upregulated. The increased SR-A was also seen at the protein level, and LDL treatment increased cellular adhesion. The induction of SR-A by LDL was inhibited by the lysosomotropic thiol WR-1065 and by the chain-breaking lipophilic antioxidant butylated hydroxytoluene (BHT). The fluorescent probe BODIPY C11 exhibited increased lipid peroxidation inside lysosomes after LDL administration. The induction of SR-A by LDL was blocked by two silencing RNAs directed against the nuclear coactivator receptor NCOA4, the cargo receptor necessary for the autophagy of ferritin. These results may point to a new pathogenetic mechanism of early-stage atherosclerosis, in which high iron stores in circulating monocytes, through increased lysosomal lipid peroxidation, may lead to an upregulated expression of SR-A, which makes the cells more adhesive and hence more atherogenic.

SNHG16 suppression enhances M2 macrophage polarization and inhibits VSMC migration in atherosclerosis

Atherosclerosis (AS) significantly impacts both cardiovascular and cerebrovascular health, making it an important area of research for potential therapeutic interventions. This study investigates the role of lncRNA SNHG16 in macrophage polarization and its effects on the progression of AS. We assessed the expression of SNHG16 in macrophages and vascular smooth muscle cells (VSMCs) treated with oxidized low-density lipoprotein (ox-LDL) using qPCR. Cell proliferation was evaluated via EdU assay and western blotting, while flow cytometry and immunofluorescence were employed to analyze the polarization of macrophages. Foam cell formation was examined using Oil Red O staining. In a co-culture system, VSMCs treated with ox-LDL were cultured alongside macrophages pretreated with sh-SNHG16, and VSMC viability, migration, and motility were assessed using CCK-8, migration, and scratch assays. The levels of inflammatory cytokines, including IL-6, IL-10, TGFβ, and TNFα, were quantified by ELISA. Our results show that SNHG16 expression is upregulated in ox-LDL-treated cells, which correlates with enhanced macrophage proliferation. Inhibition of SNHG16 promoted M1-to-M2 macrophage polarization, reducing foam cell formation and inflammation. Furthermore, SNHG16 knockdown limited VSMC viability and motility, while attenuating ox-LDL-induced inflammatory responses. In conclusion, suppression of SNHG16 favors M2 macrophage polarization and presents a potential therapeutic target for AS management.

Advances in biomimetic hydrogel for articular cartilage defect repair: Enabling immunomodulation and chondrogenesis

Articular cartilage defects, as a core pathologic feature in the progression of osteoarthritis, and their irreversible degenerative changes lead to functional impairment and socioeconomic burden for tens of millions of patients worldwide. Hydrogels have become key biomaterials in cartilage regeneration with the three-dimensional network structure, programmable mechanical properties, and cell-adaptive microenvironment of biomimetic extracellular matrix. In recent years, several hydrogel systems with in vitro/in vivo repair potential have been developed by modulating the material topology, dynamic mechanical response, and delivery of bioactive factors, and some of them have entered the clinical translation stage. This review systematically explains the biomimetic design principles of hydrogels. It analyzes the immunomodulation and chondrogenic mechanisms mediated by hydrogels, providing a theoretical framework for the development of next-generation smart cartilage repair materials.

Cellular crosstalk in fibrosis: insights into macrophage and fibroblast dynamics

Pathological fibrosis, the excessive deposition of extracellular matrix and tissue stiffening that causes progressive organ dysfunction, underlies diverse chronic diseases. The fibrotic microenvironment is driven by the dynamic microenvironmental interaction between various cell types; macrophages and fibroblasts play central roles in fibrotic disease initiation, maintenance, and progression. Macrophage functional plasticity to microenvironmental stimuli modulates fibroblast functionality by releasing pro-inflammatory cytokines, growth factors, and matrix remodeling enzymes that promote fibroblast proliferation, activation, and differentiation into myofibroblasts. Activated fibroblasts and myofibroblasts serve as the fibrotic effector cells, secreting extracellular matrix components and initiating microenvironmental contracture. Fibroblasts also modulate macrophage function through the release of their own pro-inflammatory cytokines and growth factors, creating bidirectional crosstalk that reinforces the chronic fibrotic cycle. The intricate interplay between macrophages and fibroblasts, including their secretomes and signaling interactions, leads to tissue damage and pathological loss of tissue function. In this review, we examine macrophage-fibroblast reciprocal dynamic interactions in pathological fibrotic conditions. We discuss the specific lineages and functionality of macrophages and fibroblasts implicated in fibrotic progression, with focus on their signal transduction pathways and secretory signalling that enables their pro-fibrotic behaviour. We then finish with a set of recommendations for future experimentation with the goal of developing a set of potential targets for anti-fibrotic therapeutic candidates. Understanding the cellular interactions between macrophages and fibroblasts provides valuable insights into potential therapeutic strategies to mitigate fibrotic disease progression.

Cardiomyocyte proliferation: Advances and insights in macrophage-targeted therapy for myocardial injury

In the mammalian heart, cardiomyocytes undergo a transient window of proliferation that leads to regenerative impairment, limiting cardiomyocyte proliferation and myocardial repair capacity. Cardiac developmental patterns exacerbate the progression of heart disease characterized by myocardial cell loss, ultimately leading to cardiac dysfunction and heart failure. Myocardial infarction causes the death of partial cardiomyocytes, which triggers an immune response to remove debris and restore tissue integrity. Interestingly, when transient myocardial injury triggers irreversible loss of cardiomyocytes, the subsequent macrophages responsible for proliferation and regeneration have a unique immune phenotype that promotes the formation of pre-existing new cardiomyocytes. During mammalian regeneration, mononuclear-derived macrophages and self-renewing resident cardiac macrophages provide multiple cytokines and molecular signals that create a regenerative environment and cellular plasticity capacity in postnatal cardiomyocytes, a pivotal strategy for achieving myocardial repair. Consistent with other human tissues, cardiac macrophages originating from the embryonic endothelium produce a hierarchy of contributions to monocyte recruitment and fate specification. In this review, we discuss the novel functions of macrophages in triggering cardiac regeneration and repair after myocardial infarction and provide recent advances and prospective insights into the phenotypic transformation and heterogeneous features involving cardiac macrophages. In conclusion, macrophages contribute critically to regeneration, repair, and remodeling, and are challenging targets for cardiovascular therapeutic interventions.

Expansion of Drosophila haemocytes using a conditional GeneSwitch driver affects larval haemocyte function, but does not modulate adult lifespan or survival after severe infection

Macrophages are responsible for diverse and fundamental functions in vertebrates. Drosophila blood cells (haemocytes) are dominated by cells bearing a striking homology to vertebrate macrophages (plasmatocytes). The importance of haemocytes has been demonstrated previously, with immune and developmental phenotypes observed upon haemocyte ablation. Here, we show that we can increase Hemolectin (Hml)-positive cell numbers using a constitutively active form of ras and ablate Hml-positive cell numbers using the pro-apoptotic transgene bax. However, compared with larvae, total blood cell numbers in adults were not significantly affected by experimental expansion or ablation, implying the existence of feedback mechanisms regulating haemocyte numbers. No effect on lifespan was observed from driving ras and bax in Hml-positive cells via a conditional approach (Hml-GeneSwitch). Using constitutive expression, we observed differences in lifespan; however, we attribute this to differences in genetic background. Additionally, no effect of either transgene was observed upon infection with a high dose of two different bacterial species, although pupal lethality was observed upon expansion of Hml-positive cells in a self-encapsulation mutant genetic background. The latter confirms that changes in Hml-positive cell numbers can result in phenotypes. The lack of adult phenotypes could be due to the strength of experimental manipulations or compensation via feedback mechanisms operating to regulate total blood cell numbers. Our study demonstrates the importance of conditional approaches to modulate haemocyte cell numbers, allowing for more precise study of innate immune function. This strategy could be especially fruitful to uncover mechanisms regulating total blood cell numbers across development and ageing.

Scalable Fabrication of High-Payload Dendrimer-Based Nanoparticles for Targeted Atherosclerosis Therapy

Nanoparticle-based therapeutics hold promise for the treatment of atherosclerosis, but challenges such as low drug-loading capacity and a lack of scalable, controllable production hinder their clinical translation. Flash nanoprecipitation, a continuous synthesis method, offers a potential solution for scalable and reproducible nanoparticle production. In this study, we employed a custom-designed multi-inlet vortex mixer to perform cross-linking reaction-enabled flash nanoprecipitation, facilitating controlled and scalable synthesis of cross-linked polyamidoamine (PAMAM) dendrimer nanoparticles. Notably, this approach allows simultaneous nanoparticle cross-linking and drug loading in a single step. The mannose moiety enabled specific targeting of macrophages via mannose receptors, enhancing the localization of the nanoparticles to atherosclerotic plaques. Atorvastatin calcium, a widely used clinical drug for atherosclerosis treatment, was selected as the model drug. This approach achieved both high production rates and high drug-loading capacities, with an output flow rate of 9.6 L/h and a nanoparticle concentration of approximately 0.4 g/L. The optimized formulation exhibited a drug-loading capacity of 37% and an encapsulation efficiency of 76%. In vitro and in vivo experiments demonstrated effective macrophage and plaque targeting, leading to significant therapeutic benefits. Treatment with these nanoparticles resulted in approximately 40% inhibition of aortic root plaque progression compared to the free drug-treated group. This scalable and efficient nanoparticle platform is a promising strategy for improving atherosclerosis treatment.

Macrophage polarization regulates the pathogenesis and progression of autoimmune diseases

Macrophages are integral components of the innate immune system, present in nearly all tissues and organs throughout the body. They exhibit a high degree of plasticity and heterogeneity, participating in immune responses to maintain immune homeostasis. When the immune system loses tolerance, macrophages rapidly proliferate and polarize in response to various signaling pathways within a disrupted microenvironment. The direction of macrophage polarization can be regulated by a variety of factors, including transcription factors, non-coding RNAs, and metabolic reprogramming. Autoimmune diseases arise from the immune system's activation against host cells, with macrophage polarization playing a critical role in the pathogenesis of numerous chronic inflammatory and autoimmune conditions, such as rheumatoid arthritis, systemic lupus erythematosus, immune thrombocytopenic purpura, and type 1 diabetes. Consequently, elucidating the molecular mechanisms underlying macrophage development and function presents opportunities for the development of novel therapeutic targets. This review outlines the functions of macrophage polarization in prevalent autoimmune diseases and the underlying mechanisms involved. Furthermore, we discuss the immunotherapeutic potential of targeting macrophage polarization and highlight the characteristics and recent advancements of promising therapeutic targets. Our aim is to inspire further strategies to restore macrophage balance in preventing and treating autoimmune diseases.

Key role of the CSE/transsulfuration pathway in macrophage phenotypic change under iron overload

BACKGROUND

Iron homeostasis has a significant impact on the phenotypic transformation of macrophages and is implicated in various diseases. In this study, we evaluated the effect of cystathionine-gamma-lyase (CSE)/transsulfuration pathway in iron-overload induced macrophage phenotype change.

METHODS

The biochemical parameters, such as qRT-PCR, western blot, fluorescence staining, were assessed both in vitro and in vivo.

RESULTS

Iron overload disrupts iron metabolism and alters the expression of genes involved in iron transport, resulting in the polarization of macrophages towards the M1 phenotype and an alternating activation state of M2. Meanwhile, excessive iron led to an increase in lipid peroxidation levels and disrupted cysteine metabolism. By utilizing erastin to inhibit SLC7A11 activity and block exogenous cysteine uptake, we were able to observe the exacerbation of the proinflammatory state in macrophages under conditions of cysteine deprivation. The CSE/transsulfuration pathway, serves as the primary route for endogenous cysteine synthesis. In the presence of iron overload, the expression of CSE was upregulated and further enhanced by cysteine deprivation. Deletion of CSE in CSE-knockout mice exacerbated the inflammatory transition of iron-overloaded macrophages by impacting cysteine metabolism and ferritinophagy.

CONCLUSION

The CSE/transsulfuration pathway regulated macrophage phenotype change under iron-overload, which may offer novel insights into potential therapeutic strategies for iron overload-related disorders.

Dysregulated cholesterol uptake and efflux of bone marrow-derived α-SMA+ macrophages contribute to atherosclerotic plaque formation

Macrophages play differential roles in the pathogenesis of atherosclerosis due to their different phenotypes. Although α-SMA+ macrophages have been found to present in bone marrow and atherosclerotic plaques, their role in atherosclerosis remains unclear. By performing partial carotid ligation (PCL) on monocyte/macrophage lineage-tracked mice, we observed bone marrow-derived α-SMA+ macrophages in the subendothelium and atherosclerotic plaques under disturbed flow conditions. The functional role of α-SMA+ macrophages in atherosclerotic plaque formation was examined using macrophage-specific Acta2 knockout (Acta2MKO) mice generated by crossing Acta2f/f transgenic mice with LysM-Cre mice. The size of the aortic plaques was 77.43% smaller in Acta2MKO mice than in Acta2f/f mice following adeno-associated virus-mutant PCSK9 injection and high-fat diet (HFD) feeding for 12 weeks. A significant reduction in lipid deposition, macrophage infiltration and the α-SMA+ area was observed in the aortic roots of Acta2MKO mice compared with Acta2f/f mice. Mechanistically, using Acta2-overexpressing Raw264.7 cells (Acta2hi cells) and bone marrow-derived macrophages (BMDMs) from Acta2MKO mice (Acta2MKO BMDMs), we showed that macrophage α-SMA increased the expression of the scavenger receptor SR-A, induced Ox-LDL binding and uptake, and reduced the level of the cholesterol transporter ABCA1, potentially via the AKT pathway. Together, our results indicate that bone marrow-derived α-SMA+ macrophages contribute to atherosclerotic plaque formation due to dysregulated cholesterol uptake and efflux, providing potential targets for the prevention and treatment of atherosclerosis.

Vascular inflammation in chronic kidney disease: the role of uremic toxins in macrophage activation

Chronic kidney disease (CKD) is a progressive condition characterized by the gradual loss of kidney function, leading to the accumulation of uremic toxins in the bloodstream. These toxins play a pivotal role in mediating vascular inflammation, a key contributor to the high cardiovascular morbidity and mortality observed in CKD patients. This review article explores the intricate mechanisms by which uremic toxins accelerate vascular inflammation. Macrophages, as versatile immune cells, are central to the inflammatory response. Evidence suggests that the uremic milieu influences macrophage biology. In this review article, we focus on the signaling through which uremic toxins, particularly indoxyl sulfate-an independent risk factor for cardiovascular complications in CKD patients, modulate macrophage activation and function, and how these changes contribute to vascular inflammation, leading to the increased cardiovascular risk. Investigation of such mechanisms provide molecular bases for the development of new therapies that retard the development of cardiovascular disorders in CKD patients.

Neuropathological features of cerebrovascular diseases

Optimal blood flow through a patent cerebral circulation is critical for supply of oxygen and nutrients for brain function. The integrity of vascular elements within arterial vessels of any calibre can be compromised by various disease processes. Pathological changes in the walls of veins and the venous system may also alter the dynamics of cerebral perfusion. The consequences of both systemic vascular and cerebrovascular diseases range from acute focal changes to irreversible chronic restructuring of the brain parenchyma. Cerebral infarcts of different sizes may instigate a cascade of programmed cell death mechanisms including autophagy and mitophagy and processes that range from necroptosis to ferroptosis. Recent advances also emphasise the role of the vascular inflammasome in the pathology of cerebral infarction. Here, we summarise current knowledge on frequencies, epidemiological features and the neuropathology of common cerebrovascular disorders among which cerebral small vessel diseases have become of particular interest. We also highlight the current spectrum of monogenic and polygenic genetic disorders affecting the intracranial vasculature. With the advent of DNA screening technologies, it is now realised that several cerebrovascular disorders exhibit strong genetic traits. Whilst several gene defects and their aberrant products are identified, the precise role or mechanisms of how they influence angiogenesis, vasculogenesis, vessel integrity or the extracellular matrix remain largely unclear. Despite such genetic advances, histopathological examination remains the gold standard for diagnosis and characterisation of most cerebrovascular disorders.

Study on the use of black phosphorus quantum dots in the treatment of atherosclerosis

Atherosclerosis is the pathological basis of cardiovascular disease, and there are no clinical drugs that can safely and efficiently remove atherosclerotic plaques. In this study, black phosphorus quantum dots (BPQDs) were applied to the treatment of atherosclerosis in high fat diet ApoE-/- model mice that BPQDs were given every other day for 3 weeks without changing the high-fat diet. 45.3% atherosclerotic plaque was cleared efficiently within 3 weeks in BPQDs intravenous administration way every other day. The treatment was more effective than traditional statins. The findings suggest that BPQDs have great potential to be applied for clinical prevention and treatment of AS that does not require dietary changes.

Engineered Strategies to Interfere with Macrophage Fate in Myocardial Infarction

Myocardial infarction (MI), a severe cardiovascular condition, is typically triggered by coronary artery disease, resulting in ischemic damage and the subsequent necrosis of the myocardium. Macrophages, known for their remarkable plasticity, are capable of exhibiting a range of phenotypes and functions as they react to diverse stimuli within their local microenvironment. In recent years, there has been an increasing number of studies on the regulation of macrophage behavior based on tissue engineering strategies, and its regulatory mechanisms deserve further investigation. This review first summarizes the effects of key regulatory factors of engineered biomaterials (including bioactive molecules, conductivity, and some microenvironmental factors) on macrophage behavior, then explores specific methods for inducing macrophage behavior through tissue engineering materials to promote myocardial repair, and summarizes the role of macrophage-host cell crosstalk in regulating inflammation, vascularization, and tissue remodeling. Finally, we propose some future challenges in regulating macrophage-material interactions and tailoring personalized biomaterials to guide macrophage phenotypes.

The role of natural products targeting macrophage polarization in sepsis-induced lung injury

Sepsis-induced acute lung injury (SALI) is characterized by a dysregulated inflammatory and immune response. As a key component of the innate immune system, macrophages play a vital role in SALI, in which a macrophage phenotype imbalance caused by an increase in M1 macrophages or a decrease in M2 macrophages is common. Despite significant advances in SALI research, effective drug therapies are still lacking. Therefore, the development of new treatments for SALI is urgently needed. An increasing number of studies suggest that natural products (NPs) can alleviate SALI by modulating macrophage polarization through various targets and pathways. This review examines the regulatory mechanisms of macrophage polarization and their involvement in the progression of SALI. It highlights how NPs mitigate macrophage imbalances to alleviate SALI, focusing on key signaling pathways such as PI3K/AKT, TLR4/NF-κB, JAK/STAT, IRF, HIF, NRF2, HMGB1, TREM2, PKM2, and exosome-mediated signaling. NPs influencing macrophage polarization are classified into five groups: terpenoids, polyphenols, alkaloids, flavonoids, and others. This work provides valuable insights into the therapeutic potential of NPs in targeting macrophage polarization to treat SALI.

Application of therapeutical nanoparticles with neutrophil membrane camouflaging for inflammatory plaques targeting against atherosclerosis

Atherosclerosis is the leading cause of cardiovascular disease and myocardial infarction. Precise and effective plaque targeting is a major objective for therapeutic outcomes throughout various stages of atherosclerosis. Inspired by the natural recruitment of neutrophils in atherosclerotic plaques, we fabricated a simvastatin (ST)-loaded and neutrophil membrane-cloaked nanoplatform (NNPST) for enhancing localized payload delivery and atherosclerosis management. The resulting NNPST mimicked neutrophil function and significantly decreased macrophage-mediated phagocytosis to prolong its own circulation time in the blood. Compared to pristine nanoparticles (NPST) without a membrane coating, NNPST achieved better plaque targeting in ApoE-/- mice, as indicated by neutrophils actively recruited in atherosclerotic lesions. The higher plaque homing with NNPST was monitored by dynamic fluorescence/magnetic resonance (MR) dual-modality imaging. The results further showed that NNPST efficiently prevented atherosclerosis development mainly by suppressing local inflammatory macrophages, and the percentage of plaques in the entire aortic area was reduced to 4.75 ± 1.48 % following NNPST treatment. A biosafety assessment indicated that the biomimetic NNPST induced no noticeable toxicity in the body. This approach of neutrophil membrane-camouflaged nanoparticles offers new opportunities to various therapeutic agents for on-demand delivery in neutrophil-involved inflammatory diseases.

Kupffer cells, the limelight in the liver regeneration

Kupffer cells are pivotal in initiating hepatocyte proliferation and establishing connections between different cell types during liver regeneration following partial hepatectomy. As resident macrophages within the liver, Kupffer cells collaborate with hepatocytes and non-parenchymal cells to release various inflammatory mediators that promote hepatocyte proliferation through induction signals like STAT3 phosphorylation. Additionally, the regeneration and replenishment of Kupffer cells themselves are integral components of liver regeneration. The supplementation of the Kupffer cell pool primarily occurs through two pathways: one involves local proliferation of Kupffer cells in their original location, while the other entails infiltration of circulating monocytes into the liver, followed by acquiring Kupffer cell phenotypes under the combined influence of multiple inducing factors. Extensive research has focused on intercellular crosstalk among various types of liver cells during liver regeneration, highlighting the crucial role played by Kupffer cells. This article aims to introduce Kupffer cells and their involvement in liver regeneration, as well as discuss the steady-state balance of Kupffer cell pools during this process.

Lysosome Functions in Atherosclerosis: A Potential Therapeutic Target

Lysosomes in mammalian cells are recognized as key digestive organelles, containing a variety of hydrolytic enzymes that enable the processing of both endogenous and exogenous substrates. These organelles digest various macromolecules and recycle them through the autophagy-lysosomal system. Recent research has expanded our understanding of lysosomes, identifying them not only as centers of degradation but also as crucial regulators of nutrient sensing, immunity, secretion, and other vital cellular functions. The lysosomal pathway plays a significant role in vascular regulation and is implicated in diseases such as atherosclerosis. During atherosclerotic plaque formation, macrophages initially engulf large quantities of lipoproteins, triggering pathogenic responses that include lysosomal dysfunction, foam cell formation, and subsequent atherosclerosis development. Lysosomal dysfunction, along with the inefficient degradation of apoptotic cells and the accumulation of modified low-density lipoproteins, negatively impacts atherosclerotic lesion progression. Recent studies have highlighted that lysosomal dysfunction contributes critically to atherosclerosis in a cell- and stage-specific manner. In this review, we discuss the mechanisms of lysosomal biogenesis and its regulatory role in atherosclerotic lesions. Based on these lysosomal functions, we propose that targeting lysosomes could offer a novel therapeutic approach for atherosclerosis, shedding light on the connection between lysosomal dysfunction and disease progression while offering new insights into potential anti-atherosclerotic strategies.

ALKBH5 alleviates lower extremity arteriosclerosis by regulating ITGB1 demethylation and influencing macrophage polarization

Objective

M6A methylation-regulated macrophages play an important role in the occurrence and development of arteriosclerosis. However, their role in lower extremity arteriosclerosis remains unclear. Therefore, this study aims to explore the key factors that regulate arteriosclerosis methylation in the lower extremities and the mechanism by which they affect arteriosclerosis by influencing macrophage polarization.

Methods

The m6A methylation levels in peripheral blood mononuclear cells (PBMCs) of patients with lower extremity atherosclerosis was investigated using the Dot blot method. Additionally, the expression levels of RNA methyltransferases and demethylases were examined using ELISA and Western blotting. Inflammatory macrophages were established using RAW264.7 cells stimulated with LPS (100 ng/mL), and the expression of ALKBH5 and ITGB1 was evaluated using Western blotting. Immunofluorescence staining was conducted to assess the expression of M1 macrophage markers (F4/80+CD86) and M2 macrophage markers (F4/80+CD206) in renal tissue. ELISA was employed to measure the levels of cytokines (IL-6, IL-1β, TNF-a, IL-10, and TGF-β) and plasma lipid levels in mice. An atherosclerosis model was established in ApoE-/- mice through balloon pull surgery and high-fat feeding. Oil Red O staining and hematoxylin and eosin (HE) staining were performed to measure the area of atherosclerotic plaques and the size of the necrotic core in mouse femoral artery, respectively. Additionally, Starbase2.0 was used for downstream target gene prediction of ALKBH5. The half-life of ITGB1 was evaluated using RT-qPCR.

Results

The m6A methylation levels were significantly increased in PBMCs of patients with lower extremity atherosclerosis. Among them, the expression of the RNA demethylase ALKBH5 was the lowest in PBMCs of patients with lower extremity atherosclerosis. Further analysis revealed that ALKBH5 can alleviate the progression of lower extremity atherosclerosis and promote the polarization of M2 macrophages. ALKBH5 can reduce the stability of ITGB1 through demethylation. Mechanistically, ALKBH5 influences macrophage polarization and mitigates lower extremity atherosclerosis by affecting the demethylation of ITGB1.

Conclusion

ALKBH5 promotes M2 macrophage polarization and alleviates lower extremity atherosclerosis by regulating the demethylation of ITGB1. A deeper understanding of this process not only helps elucidate the molecular mechanisms of atherosclerosis but also provides possibilities for the development of new therapeutic strategies.

Vitamin D, immune function, and atherosclerosis. Where are we now?

The role of vitamin D in regulating calcium metabolism and skeletal growth and disease is widely recognized. Indeed, current recommendations for serum vitamin D concentrations are based on these parameters. A serum vitamin D <20 ng/mL is considered deficient, concentrations between 20 and 30 ng/mL are insufficient, and >30 ng/mL is adequate. However, over the past number of years, epidemiological studies, randomized clinical trials, and preclinical animal and cell culture-based research have demonstrated that vitamin D modulates immune function. Cardiovascular disease (CVD), the leading cause of morbidity and mortality in the United States and in industrialized nations, is mediated in part by chronic inflammation as well as by other well-established risk factors including dyslipidemia, hypertension, obesity, and diabetes. Vitamin D deficiency (<20 ng/mL or <50 nM) is associated with increased CVD risk. As described in this review, several recent systematic reviews and meta-analyses provide some evidence that vitamin D administration to individuals with vitamin D deficiency may have little effect on CVD-related mortality. Many well-designed randomized clinical trials in the general population as well as in people at risk for CVD-related complication later in life provide evidence that treatment may be beneficial. These latter studies as well as the paucity of information regarding the optimal vitamin D concentration required for optimizing immune function in patients indicate that more research is needed to address whether vitamin D supplements may be a cost-effective intervention for preventing CVD.

Immunologic role of macrophages in sepsis-induced acute liver injury

Sepsis-induced acute liver injury (SALI), a manifestation of sepsis multi-organ dysfunction syndrome, is associated with poor prognosis and high mortality. The diversity and plasticity of liver macrophage subpopulations explain their different functional responses in different liver diseases. Kupffer macrophages, liver capsular macrophages, and monocyte-derived macrophages are involved in pathogen recognition and clearance and in the regulation of inflammatory responses, exacerbating the progression of SALI through different pathways of pyroptosis, ferroptosis, and autophagy. Concurrently, they play an important role in maintaining hepatic homeostasis and in the injury and repair processes of SALI. Other macrophages are recruited to diseased tissues under pathological conditions and are polarized into various phenotypes (mainly M1 and M2 types) under the influence of signaling molecules, transcription factors, and metabolic reprogramming, thereby exerting different roles and functions. This review provides an overview of the immune role of macrophages in SALI and discusses the multiple roles of macrophages in liver injury and repair to provide a reference for future studies.

Single-cell analysis identified key macrophage subpopulations associated with atherosclerosis

Background

Atherosclerosis is a lipid-driven inflammatory disease characterized by plaque formation in major arteries. These plaques contain lipid-rich macrophages that accumulate through monocyte recruitment, local macrophage differentiation, and proliferation.

Objective

We identify the macrophage subsets that are closely related to atherosclerosis and reveal the key pathways in the progression of atherosclerotic disease.

Materials and methods

In this study, we characterize the single-cell landscape of atherosclerosis, identifying macrophage subsets closely related to the disease and revealing key pathways in its progression. Using analytical methods like CytoTRACE, Monocle2, Slingshot, and CellChat, we study macrophage differentiation and infer cell trajectory.

Results

The 8,417 macrophages were divided into six subtypes, macrophages: C0 C1QC+ macrophages, C1 SPP1+ macrophages, C2 FCN1+ macrophages, C3 IGKC+ macrophages, C4 FCER1A+ macrophages, C5CALD1+ macrophages. The results of gene set enrichment analysis, Monocle2, and Slingshot suggest that C2 FCN1+ macrophages may play an important role in the progression of atherosclerosis. C2 FCN1+ macrophages interact with endothelial cells via CCL, CXCL, APP, and other pathways to regulate the progression of atherosclerosis.

Conclusion

We identify a key macrophage subgroup (C2 FCN1+ macrophages) associated with atherosclerosis, which interacts with endothelial cells via CCL, CXCL, APP, and other pathways to regulate disease progression.

Screening and regulatory mechanism exploration of M1 macrophage polarization and efferocytosis-related biomarkers in coronary heart disease

Background

Macrophage polarization and efferocytosis have been implicated in CHD. However, the underlying mechanisms remain elusive. This study aimed to identify CHD-associated biomarkers using transcriptomic data.

Methods

This study examined 74 efferocytosis-related genes (ERGs) and 17 M1 macrophage polarization-related genes (MRGs) across two CHD-relevant datasets, GSE113079 and GSE42148. Differential expression analysis was performed separately on each dataset to identify differentially expressed genes (DEGs1 and DEGs2). The intersection of upregulated and downregulated genes from both sets was then used to define the final DEGs. Subsequently, MRG and ERG scores were calculated within the GSE113079 dataset, followed by weighted gene co-expression network analysis (WGCNA) to identify key module genes. The overlap between these module genes and the DEGs yielded candidate biomarkers, which were further evaluated through machine learning, receiver operating characteristic (ROC) curve analysis, and expression profiling. These biomarkers were subsequently leveraged to explore immune infiltration patterns and to construct a molecular regulatory network. To further validate their expression, quantitative reverse transcriptase PCR (qRT-PCR) was performed on clinical CHD samples, confirming the relevance and expression patterns of these biomarkers in the disease.

Results

A total of 93 DEGs were identified by intersecting the upregulated and downregulated genes from DEGs1 and DEGs2. WGCNA of the MRG and ERG scores identified 15,936 key module genes in the GSE113079 dataset. Machine learning and ROC analysis highlighted four biomarkers: C5orf58, CTAG1A, ZNF180, and IL13RA1. Among these, C5orf58, and ZNF180 were downregulated in CHD cases, while CTAG1A and IL13RA1 was upregulated. qRT-PCR results validated these findings for C5orf58, CTAG1A, ZNF180, and IL13RA1 showed inconsistent expression trends. Immune infiltration analysis indicated IL13RA1 all had a positive correlation with M0 macrophage, while had a negative correlation with. NK cells activated. The molecular regulatory network displayed that GATA2 and YY1 could regulate CTAG1A and ZNF180.

Conclusions

These results suggest that C5orf58, CTAG1A, ZNF180, and IL13RA1 serve as biomarkers linking M1 macrophage polarization and efferocytosis to CHD, providing valuable insights for CHD diagnosis and therapeutic strategies.

Long-term expanded hepatic progenitor cells ameliorate D-GalN/LPS-induced acute liver failure through repolarizing M1 macrophage to M2-Like phenotype via activation of the IL-10/JAK2/STAT3 signaling pathway

Acute liver failure (ALF) is a devastating liver disease characterized by the rapid deterioration of hepatocytes, which causes a series of clinical complications, including hepatic dysfunction, coagulopathy, encephalopathy, and multiorgan failure. Cell-based therapy is a promising alternative as it can bridge patients until their livers regenerate, releasing immunomodulatory molecules to suppress inflammation. This study reports an iPSCs-derived long-term expanded hepatic progenitor cell (LTHepPCs), which can differentiate into hepatocyte-like cells (HLCs) in vivo. When introduced into drug-induced ALF models, LTHepPCs mitigate liver damage by modulating the local immune microenvironment. This is achieved by shifting macrophages/Kupffer cells towards an anti-inflammatory state, resulting in a decrease in the expression of inflammatory cytokines such as TNF-a, IL-1β, and IL-8, and an increase in the expression of anti-inflammatory cytokines such as IL-10 and ARG-1. In vitro co-culturing of THP-1 or mBMDMs with LTHepPCs suggested that LTHepPCs could activate the anti-inflammatory state of macrophages/Kupffer cells via the IL-10/JAK2/STAT3 signaling pathway. Therefore, LTHepPC transplantation is a promising therapy for ALF patients.

Biological functions and molecular mechanisms of exosome-derived circular RNAs and their clinical implications in digestive malignancies: the vintage in the bottle

BACKGROUND

Circular RNAs (circRNAs) are identified as a novel family of endogenous RNA molecules through 'back-splicing' and covalently linked at the 5' and 3' ends. Emerging researches have demonstrated circRNAs are stable and abundant in exosomes called exosomal circRNAs (exo-circRNA).

MATERIALS AND METHODS

We searched recent studies and references to summary the research progress of exosomal circRNA.

RESULTS

Recent studies have revealed that exosome-derived circRNAs including exo-CDR1as, exo-circRanGAP1, exo-circIAR play vital roles in cell proliferation and apoptosis, epithelial mesenchymal transition, invasion and metastasis, angiogenesis, immune evasion, cellular crosstalk, cancer cachexia through a variety of biological mechanisms, such as serving as microRNA sponges, interacting with RNA binding proteins, regulating gene transcription, N6-Methyladenosine modification and so on. Due to their characteristics of origin, structure, properties and biological functions, exo-circRNAs are expected to apply in precious diagnosis and prognostic indicators, improving drug and radiation resistance and sensitivity, becoming biological therapeutic targets.

CONCLUSION

We summarize the update of digestive malignancies associated exo-circRNAs in biogenesis, biological functions, molecular mechanisms, clinical implications, potential applications and experimental technique in order to effectively promote transformation and application in the future.

Current status of research on the mechanisms of tumor-associated macrophages in esophageal cancer progression

Esophageal carcinoma (EC) is one of the most common tumors in China and seriously affects patient survival and quality of life. In recent years, increasing studies have shown that the tumor microenvironment is crucial in promoting tumor progression and metastasis. Tumor-associated macrophages (TAM) are key components of the tumor immune microenvironment and promote both tumor growth and antitumor immunity. Much evidence suggests that TAMs are closely associated with esophageal tumors. However, understanding of the clinical value and mechanism of action of TAM in esophageal cancer remains limited. Therefore, we reviewed the status of research on the role and mechanism of action of TAM in EC progression and summarized its potential clinical application value to provide a theoretical basis for the clinical treatment of EC.

Pharmacological therapy targeting the immune response in atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease characterized by the formation of atherosclerotic plaques that consist of numerous cells including smooth muscle cells, endothelial cells, immune cells, and foam cells. The most abundant innate and adaptive immune cells, including neutrophils, monocytes, macrophages, B cells, and T cells, play a pivotal role in the inflammatory response, lipoprotein metabolism, and foam cell formation to accelerate atherosclerotic plaque formation. In this review, we have discussed the underlying mechanisms of activated immune cells in promoting AS and reviewed published clinical trials for the treatment of AS by suppressing immune cell activation. We have also presented some crucial shortcomings of current clinical trials. Lastly, we have discussed the therapeutic potential of novel compounds, including herbal medicine and dietary food, in alleviating AS in animals. Despite these limitations, further clinical trials and experimental studies will enhance our understanding of the mechanisms modulated by immune cells and promote widespread drug use to treat AS by suppressing immune system-induced inflammation.

Identification of iron metabolism-related genes in coronary heart disease and construction of a diagnostic model

Background

Coronary heart disease is a common cardiovascular disease, yferroptosiset its relationship with iron metabolism remains unclear.

Methods

Gene expression data from peripheral blood samples of patients with coronary heart disease and a healthy control group were utilized for a comprehensive analysis that included differential expression analysis, weighted gene co-expression network analysis, gene enrichment analysis, and the development of a logistic regression model to investigate the associations and differences between the groups. Additionally, the CIBERSORT algorithm was employed to examine the composition of immune cell types within the samples.

Results

Eight central genes were identified as being both differentially expressed and related to iron metabolism. These central genes are mainly involved in the cellular stress response. A logistic regression model based on the central genes achieved an AUC of 0.64-0.65 in the diagnosis of coronary heart disease. A higher proportion of M0 macrophages was found in patients with coronary heart disease, while a higher proportion of CD8T cells was observed in the normal control group.

Conclusion

The study identified important genes related to iron metabolism in the pathogenesis of coronary heart disease and constructed a robust diagnostic model. The results suggest that iron metabolism and immune cells may play a significant role in the development of coronary heart disease, providing a basis for further research.

Unraveling Macrophage Polarization: Functions, Mechanisms, and "Double-Edged Sword" Roles in Host Antiviral Immune Responses

Numerous viruses that propagate through the respiratory tract may be initially engulfed by macrophages (Mφs) within the alveoli, where they complete their first replication cycle and subsequently infect the adjacent epithelial cells. This process can lead to significant pathological damage to tissues and organs, leading to various diseases. As essential components in host antiviral immune systems, Mφs can be polarized into pro-inflammatory M1 Mφs or anti-inflammatory M2 Mφs, a process involving multiple signaling pathways and molecular mechanisms that yield diverse phenotypic and functional features in response to various stimuli. In general, when infected by a virus, M1 macrophages secrete pro-inflammatory cytokines to play an antiviral role, while M2 macrophages play an anti-inflammatory role to promote the replication of the virus. However, recent studies have shown that some viruses may exhibit the opposite trend. Viruses have evolved various strategies to disrupt Mφ polarization for efficient replication and transmission. Notably, various factors, such as mechanical softness, the altered pH value of the endolysosomal system, and the homeostasis between M1/M2 Mφs populations, contribute to crucial events in the viral replication cycle. Here, we summarize the regulation of Mφ polarization, virus-induced alterations in Mφ polarization, and the antiviral mechanisms associated with these changes. Collectively, this review provides insights into recent advances regarding Mφ polarization in host antiviral immune responses, which will contribute to the development of precise prevention strategies as well as management approaches to disease incidence and transmission.

Regulatory T cells and macrophages in atherosclerosis: from mechanisms to clinical significance

Atherosclerosis is a complex pathological process, which causes diseases that threaten the health of an increasing number of people. Studies have found that the original view of lipid accumulation is not comprehensive because the use of lipid-lowering drugs alone cannot effectively treat atherosclerosis. As the study of the pathogenesis of atherosclerosis develops in-depth, the impact of immune-inflammatory response on atherosclerosis has garnered a great deal of attention. Some new advances have been made in the role of regulatory T cells (Tregs) and macrophages with unique immunomodulatory functions in atherosclerosis. Herein, the role of Tregs, macrophages, the mechanisms of Tregs-regulated macrophages, and the effects of potential factors on Tregs and macrophages in atherosclerosis are overviewed. Targeting Tregs and macrophages may provide new research strategies for the treatment of atherosclerosis in the clinic.

Efferocytosis in atherosclerosis

Cardiovascular disease is the leading cause of death worldwide, and it commonly results from atherosclerotic plaque progression. One of the increasingly recognized drivers of atherosclerosis is dysfunctional efferocytosis, a homeostatic mechanism responsible for the clearance of dead cells and the resolution of inflammation. In atherosclerosis, the capacity of phagocytes to participate in efferocytosis is hampered, leading to the accumulation of apoptotic and necrotic tissue within the plaque, which results in enlargement of the necrotic core, increased luminal stenosis and plaque inflammation, and predisposition to plaque rupture or erosion. In this Review, we describe the different forms of programmed cell death that can occur in the atherosclerotic plaque and highlight the efferocytic machinery that is normally implicated in cardiovascular physiology. We then discuss the mechanisms by which efferocytosis fails in atherosclerosis and other cardiovascular and cardiometabolic diseases, including myocardial infarction and diabetes mellitus, and discuss therapeutic approaches that might reverse this pathological process.

Atherosis-associated lnc_000048 activates PKR to enhance STAT1-mediated polarization of THP-1 macrophages to M1 phenotype

JOURNAL/nrgr/04.03/01300535-202419110-00029/figure1/v/2024-03-08T184507Z/r/image-tiff Our previous study has demonstrated that lnc_000048 is upregulated in large-artery atherosclerotic stroke and promotes atherosclerosis in ApoE-/- mice. However, little is known about the role of lnc_000048 in classically activated macrophage (M1) polarization. In this study, we established THP-1-derived testing state macrophages (M0), M1 macrophages, and alternately activated macrophages (M2). Real-time fluorescence quantitative PCR was used to verify the expression of marker genes and the expression of lnc_000048 in macrophages. Flow cytometry was used to detect phenotypic proteins (CD11b, CD38, CD80). We generated cell lines with lentivirus-mediated upregulation or downregulation of lnc_000048. Flow cytometry, western blot, and real-time fluorescence quantitative PCR results showed that down-regulation of lnc_000048 reduced M1 macrophage polarization and the inflammation response, while over-expression of lnc_000048 led to the opposite effect. Western blot results indicated that lnc_000048 enhanced the activation of the STAT1 pathway and mediated the M1 macrophage polarization. Moreover, catRAPID prediction, RNA-pull down, and mass spectrometry were used to identify and screen the protein kinase RNA-activated (PKR), then catRAPID and RPIseq were used to predict the binding ability of lnc_000048 to PKR. Immunofluorescence (IF)-RNA fluorescence in situ hybridization (FISH) double labeling was performed to verify the subcellular colocalization of lnc_000048 and PKR in the cytoplasm of M1 macrophage. We speculate that lnc_000048 may form stem-loop structure-specific binding and activate PKR by inducing its phosphorylation, leading to activation of STAT1 phosphorylation and thereby enhancing STAT1 pathway-mediated polarization of THP-1 macrophages to M1 and inflammatory factor expression. Taken together, these results reveal that the lnc_000048/PKR/STAT1 axis plays a crucial role in the polarization of M1 macrophages and may be a novel therapeutic target for atherosclerosis alleviation in stroke.

Macrophage and chondrocyte phenotypes in inflammation

Inflammation is a complex biological process protecting the body from diverse external threats. Effectively performing this task requires an intricate, well-regulated interplay of different cells and tissues. Furthermore, several cells participating in inflammation can assume diverse phenotypes. A classic and relatively well-studied example of phenotypic diversity in inflammation is macrophage polarization. Based on the TH1/TH2 phenotypes of T helper cells, this scheme has proinflammatory "classical/M1" activation contrasted with the anti-inflammatory and healing-promoting "alternative/M2" phenotype. Some authors have extended the concept into an M17 phenotype induced by the classic TH17 cytokine IL-17. Phenotypic changes in chondrocytes have also been studied especially in the context of osteoarthritis (OA), and there are indications that these cells can also assume polarized phenotypes at least partly analogous to those of TH cells and macrophages. The therapeutic success of biological agents targeting TH1/TH2/TH17 inductor and/or effector cytokines displays the utility of the concept of polarization. The aim of this focused review is to survey the internal and external factors affecting macrophage and chondrocyte phenotypes (such as inflammatory cytokines, widely used medications and natural products) and to explore the possibility of ameliorating pathological states by modulating these phenotypes.

Gene-Engineered Cerium-Exosomes Mediate Atherosclerosis Therapy Through Remodeling of the Inflammatory Microenvironment and DNA Damage Repair

The pro-inflammatory immune microenvironment in the localized lesion areas and the absence of DNA damage repair mechanisms in endothelial cells serve as essential accelerating factors in the development of atherosclerosis. The lack of targeted therapeutic strategies represents a significant limitation in the efficacy of therapeutic agents for atherosclerosis. In this study, Genetically engineered SNHG12-loaded cerium-macrophage exosomes (Ce-Exo) are designed as atherosclerosis-targeting agents. In vivo studies demonstrated that Ce-Exo exhibited multivalent targeting properties for macrophages, with a 4.1-fold higher atherosclerotic plaque-aggregation ability than that of the control drugs. This suggests that Ce-Exo has a higher homing capacity and deeper penetration into the atherosclerotic plaque. In apolipoprotein E-deficient mice, Ce-Exo found to effectively remodel the immune microenvironment in the lesion area, repair endothelial cell damage, and inhibit the development of atherosclerosis. This study provides a novel approach to the treatment of atherosclerosis and demonstrates the potential of cell-derived drug carriers in biomedicine.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

The axis of tumor-associated macrophages, extracellular matrix proteins, and cancer-associated fibroblasts in oncogenesis

The extracellular matrix (ECM) is a complex, dynamic network of multiple macromolecules that serve as a crucial structural and physical scaffold for neighboring cells. In the tumor microenvironment (TME), ECM proteins play a significant role in mediating cellular communication between cancer-associated fibroblasts (CAFs) and tumor-associated macrophages (TAMs). Revealing the ECM modification of the TME necessitates the intricate signaling cascades that transpire among diverse cell populations and ECM proteins. The advent of single-cell sequencing has enabled the identification and refinement of specific cellular subpopulations, which has substantially enhanced our comprehension of the intricate milieu and given us a high-resolution perspective on the diversity of ECM proteins. However, it is essential to integrate single-cell data and establish a coherent framework. In this regard, we present a comprehensive review of the relationships among ECM, TAMs, and CAFs. This encompasses insights into the ECM proteins released by TAMs and CAFs, signaling integration in the TAM-ECM-CAF axis, and the potential applications and limitations of targeted therapies for CAFs. This review serves as a reliable resource for focused therapeutic strategies while highlighting the crucial role of ECM proteins as intermediates in the TME.

Macrophages regulate plaque progression in diabetic Apoe-/- mice dependent on Pi4p/Nlrp3 signaling pathway

BACKGROUND AND AIMS

Atherosclerotic cardiovascular disease complicated by diabetes mellitus (DM) is the leading cause of death in diabetic patients, and it is strongly associated with macrophages and inflammasomes. It has been found that activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome is closely associated with phosphatidylinositol 4-phosphate (PI4P) on the trans-Golgi. However, how PI4P and NLRP3 regulate macrophage function and its role in diabetic atherosclerotic plaques is unclear.

METHODS

The expression of Pi4p and Nlrp3-inflammasome-related proteins in atherosclerosis in apolipoprotein E-deficient (Apoe-/-) and Apoe-/- DM mice was investigated. Then, Pi4p levels were affected by shRNA-Pi4kb or cDNA-Sac1 plasmid to investigate the effects of changes in Pi4p-related metabolic enzymes on macrophage function. Finally, genetically modified macrophages were injected into diabetic Apoe-/- mice to explore the effects on atherosclerosis.

RESULTS

DM promoted plaque progression in atherosclerotic mice and increased expression of Pi4p and Nlrp3 in plaques. In addition, impaired macrophage function induced by high glucose was reversed by transfected shRNA-Pi4kb or cDNA-Sac1 plasmid. Furthermore, decreased levels of Pi4p reduced plaque area in diabetic Apoe-/- mice.

CONCLUSIONS

Our data suggests that Pi4p/Nlrp3 in macrophages play an important role in the exacerbation of atherosclerosis in diabetic mice. Pi4p-related metabolizing enzymes (PI4KB and SAC1) may be a potential therapeutic strategy for diabetic atherosclerosis, and macrophage therapy is also a potential treatment.

PDIA3 defines a novel subset of adipose macrophages to exacerbate the development of obesity and metabolic disorders

Adipose tissue macrophages (ATMs) play important roles in maintaining adipose tissue homeostasis and orchestrating metabolic inflammation. Given the extensive functional heterogeneity and phenotypic plasticity of ATMs, identification of the authentically pathogenic ATM subpopulation under obese setting is thus necessitated. Herein, we performed single-nucleus RNA sequencing (snRNA-seq) and unraveled a unique maladaptive ATM subpopulation defined as ATF4hiPDIA3hiACSL4hiCCL2hi inflammatory and metabolically activated macrophages (iMAMs), in which PDIA3 is required for the maintenance of their migratory and pro-inflammatory properties. Mechanistically, ATF4 serves as a metabolic stress sensor to transcribe PDIA3, which then imposes a redox control on RhoA activity and strengthens the pro-inflammatory and migratory properties of iMAMs through RhoA-YAP signaling. Administration of Pdia3 small interfering RNA (siRNA)-loaded liposomes effectively repressed adipose inflammation and high-fat diet (HFD)-induced obesity. Together, our data support that strategies aimed at targeting iMAMs by suppressing PDIA3 expression or activity could be a viable approach against obesity and metabolic disorders in clinical settings.

Targeting Macrophage Phenotypes and Metabolism as Novel Therapeutic Approaches in Atherosclerosis and Related Cardiovascular Diseases

PURPOSE OF THE REVIEW

Macrophage accumulation and activation function as hallmarks of atherosclerosis and have complex and intricate dynamics throughout all components and stages of atherosclerotic plaques. In this review, we focus on the regulatory roles and underlying mechanisms of macrophage phenotypes and metabolism in atherosclerosis. We highlight the diverse range of macrophage phenotypes present in atherosclerosis and their potential roles in progression and regression of atherosclerotic plaque. Furthermore, we discuss the challenges and opportunities in developing therapeutic strategies for preventing and treating atherosclerotic cardiovascular disease.

RECENT FINDINGS

Dysregulation of macrophage polarization between the proinflammatory M1 and anti-inflammatory M2 phenotypealters the immuno-inflammatory response during atherosclerosis progression, leading to plaque initiation, growth, and ultimately rupture. Altered metabolism of macrophage is a key feature for their function and the subsequent progression of atherosclerotic cardiovascular disease. The immunometabolism of macrophage has been implicated to macrophage activation and metabolic rewiring of macrophages within atherosclerotic lesions, thereby shifting altered macrophage immune-effector and tissue-reparative function. Targeting macrophage phenotypes and metabolism are potential therapeutic strategies in the prevention and treatment of atherosclerosis and atherosclerotic cardiovascular diseases. Understanding the precise function and metabolism of specific macrophage subsets and their contributions to the composition and growth of atherosclerotic plaques could reveal novel strategies to delay or halt development of atherosclerotic cardiovascular diseases and their associated pathophysiological consequences. Identifying biological stimuli capable of modulating macrophage phenotypes and metabolism may lead to the development of innovative therapeutic approaches for treating patients with atherosclerosis and coronary artery diseases.

Phenotypic, Metabolic, and Functional Characterization of Experimental Models of Foamy Macrophages: Toward Therapeutic Research in Atherosclerosis

Different types of macrophages (Mφ) are involved in atherogenesis, including inflammatory Mφ and foamy Mφ (FM). Our previous study demonstrated that two-photon excited fluorescence (TPEF) imaging of NADH and FAD autofluorescence (AF) could distinguish experimental models that mimic the different atherosclerotic Mφ types. The present study assessed whether optical differences correlated with phenotypic and functional differences, potentially guiding diagnostic and therapeutic strategies. Phenotypic differences were investigated using three-dimensional principal component analysis and multi-color flow cytometry. Functional analyses focused on cytokine production, metabolic profiles, and cellular oxidative stress, in LDL dose-dependent assays, to understand the origin of AF in the FAD spectrum and assess FM ability to transition toward an immunoregulatory phenotype and function. Phenotypic studies revealed that FM models generated with acetylated LDL (Mac) were closer to immunoregulatory Mφ, while those generated with oxidized LDL (Mox) more closely resembled inflammatory Mφ. The metabolic analysis confirmed that inflammatory Mφ primarily used glycolysis, while immunoregulatory Mφ mainly depended on mitochondrial respiration. FM models employed both pathways; however, FM models generated with high doses of modified LDL showed reduced mitochondrial respiration, particularly Mox FM. Thus, the high AF in the FAD spectrum in Mox was not linked to increased mitochondrial respiration, but correlated with the dose of oxidized LDL, leading to increased production of reactive oxygen species (ROS) and lysosomal ceroid accumulation. High FAD-like AF, ROS, and ceroid accumulation were reduced by incubation with α-tocopherol. The cytokine profiles supported the phenotypic analysis, indicating that Mox FM exhibited greater inflammatory activity than Mac FM, although both could be redirected toward immunoregulatory functions, albeit to different degrees. In conclusion, in the context of immunoregulatory therapies for atherosclerosis, it is crucial to consider FM, given their prevalence in plaques and our results, as potential targets, regardless of their inflammatory status, alongside non-foamy inflammatory Mφ.

Single-cell RNA sequencing identifies interferon-inducible monocytes/macrophages as a cellular target for mitigating the progression of abdominal aortic aneurysm and rupture risk

AIMS

Abdominal aortic aneurysm (AAA) represents a life-threatening condition characterized by medial layer degeneration of the abdominal aorta. Nevertheless, knowledge regarding changes in regulators associated with aortic status remains incomplete. A thorough understanding of cell types and signalling pathways involved in the development and progression of AAAs is essential for the development of medical therapy.

METHODS AND RESULTS

We harvested specimens of the abdominal aorta with different pathological features in Angiotensin II (AngII)-infused ApoE-/- mice, conducted scRNA-seq, and identified a unique population of interferon-inducible monocytes/macrophages (IFNICs), which were amply found in the AAAs. Gene set variation analysis revealed that activation of the cytosolic DNA sensing cGAS-STING and JAK-STAT pathways promoted the secretion of type I interferons in monocytes/macrophages and differentiated them into IFNICs. We generated myeloid cell-specific deletion of Sting1 (Lyz2-Cre+/-; Sting1flox/flox) mice and performed bone marrow transplantation and found that myeloid cell-specific deletion of Sting1 or Ifnar1 significantly reduced the incidence of AAA, aortic rupture rate, and diameter of the abdominal aorta. Mechanistically, the activated pyroptosis- and inflammation-related signalling pathways, regulated by IRF7 in IFNICs, play critical roles in the developing AAAs.

CONCLUSION

IFNICs are a unique monocyte/macrophage subset implicated in the development of AAAs and aortic rupture.

Natural plant-derived polysaccharides targeting macrophage polarization: a promising strategy for cancer immunotherapy

Tumor associated macrophages (TAMs) are the predominant innate immune cells in the tumor microenvironment (TME). Cytokines induce the differentiation of macrophages into distinct types of TAMs, primarily characterized by two phenotypes: M1-polarized and M2-polarized. Cancer growth is suppressed by M1-polarized macrophages and promoted by M2-polarized macrophages. The regulation of macrophage M1 polarization has emerged as a promising strategy for cancer immunotherapy. Polysaccharides are important bioactive substances found in numerous plants, manifesting a wide range of noteworthy biological actions, such as immunomodulation, anti-tumor effects, antioxidant capabilities, and antiviral functions. In recent years, there has been a significant increase in interest regarding the immunomodulatory and anti-tumor properties of polysaccharides derived from plants. The regulatory impact of polysaccharides on the immune system is mainly associated with the natural immune response, especially with the regulation of macrophages. This review provides a thorough analysis of the regulatory effects and mechanisms of plant polysaccharides on TAMs. Additionally, an analysis of potential opportunities for clinical translation of plant polysaccharides as immune adjuvants is presented. These insights have greatly advanced the research of plant polysaccharides for immunotherapy in tumor-related applications.

Exploring the relationship between lipid metabolism and cognition in individuals living with stable-phase Schizophrenia: a small cross-sectional study using Olink proteomics analysis

BACKGROUND

Cognitive impairment is a core symptom of schizophrenia. Metabolic abnormalities impact cognition, and although the influence of blood lipids on cognition has been documented, it remains unclear. We conducted a small cross-sectional study to investigate the relationship between blood lipids and cognition in patients with stable-phase schizophrenia. Using Olink proteomics, we explored the potential mechanisms through which blood lipids might affect cognition from an inflammatory perspective.

METHODS

A total of 107 patients with stable-phase schizophrenia and cognitive impairment were strictly included. Comprehensive data collection included basic patient information, blood glucose, blood lipids, and body mass index. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and the MATRICS Consensus Cognitive Battery (MCCB). After controlling for confounding factors, we identified differential metabolic indicators between patients with mild and severe cognitive impairment and conducted correlation and regression analyses. Furthermore, we matched two small sample groups of patients with lipid metabolism abnormalities and used Olink proteomics to analyze inflammation-related differential proteins, aiming to further explore the association between lipid metabolism abnormalities and cognition.

RESULTS

The proportion of patients with severe cognitive impairment (SCI) was 34.58%. Compared to patients with mild cognitive impairment (MCI), those with SCI performed worse in the Attention/Alertness (t = 2.668, p = 0.009) and Working Memory (t = 2.496, p = 0.014) cognitive dimensions. Blood lipid metabolism indicators were correlated with cognitive function, specifically showing that higher levels of TG (r = -0.447, p < 0.001), TC (r = -0.307, p = 0.002), and LDL-C (r = -0.607, p < 0.001) were associated with poorer overall cognitive function. Further regression analysis indicated that TG (OR = 5.578, P = 0.003) and LDL-C (OR = 5.425, P = 0.001) may be risk factors for exacerbating cognitive impairment in individuals with stable-phase schizophrenia. Proteomics analysis revealed that, compared to individuals with stable-phase schizophrenia and normal lipid metabolism, those with hyperlipidemia had elevated levels of 10 inflammatory proteins and decreased levels of 2 inflammatory proteins in plasma, with these changes correlating with cognitive function. The differential proteins were primarily involved in pathways such as cytokine-cytokine receptor interaction, chemokine signaling pathway, and IL-17 signaling pathway.

CONCLUSION

Blood lipids are associated with cognitive function in individuals with stable-phase schizophrenia, with higher levels of TG, TC, and LDL-C correlating with poorer overall cognitive performance. TG and LDL-C may be risk factors for exacerbating cognitive impairment in these patients. From an inflammatory perspective, lipid metabolism abnormalities might influence cognition by activating or downregulating related proteins, or through pathways such as cytokine-cytokine receptor interaction, chemokine signaling pathway, and IL-17 signaling pathway.

Cholesterol and Cytokines: Molecular Links to Atherosclerosis and Carcinogenesis

An increase of cholesterol concentration within the artery obstructs arterial blood flow once it deposits alongside the arterial wall. This results in atherosclerosis. Carcinogenesis causes a quicker clearance of vascular cholesterol to meet the demands of tumour cell development. Both illnesses have an increased concentration of pro-inflammatory cytokines in the blood. To search the comparative characteristics of cholesterol and pro-inflammatory cytokines in the pathogenesis of atherosclerosis and carcinogenesis, a comprehensive online survey using MEDLINE, Scopus, PubMed, and Google Scholar was conducted for relevant journals with key search term cholesterol and cytokines in atherosclerotic and cancerous patients. According to reports, hypercholesterolaemia related dyslipidemia causes atherosclerosis in blood arteries and hypercholesterolaemia in cell nucleus is a reason for developing carcinogenesis. It is also noted that pro-inflammatory cytokines are involved in both of the aforementioned pathogenesis. Changes in anti-inflammatory cytokines are only the characteristic features of each kind. Thus, Cholesterol and pro-inflammatory cytokines are intensely interlinked in the genesis of atherosclerotic and carcinogenic consequences.

In Vitro Modulation of Human Foam Cell Formation and Adhesion Molecules Expression by Ginger Extracts Points to Potential Cardiovascular Preventive Agents

Recent findings from the World Heart Federation (WHF) reported a significant increase in cardiovascular disease (CVD)-related deaths, highlighting the urgent need for effective prevention strategies. Atherosclerosis, a key precursor to CVD, involves the accumulation of low-density lipoprotein (LDL) and its oxidation within the endothelium, leading to inflammation and foam cell formation. Ginger extracts, known for their antioxidative and anti-inflammatory properties, show promise in preventing CVD initiation by inhibiting LDL oxidation and reducing foam cell formation. Our results revealed that the active fractions in ginger extracts had antioxidative effects, particularly fractions D and E. Further research is needed to identify the active compounds in these fractions and understand their mechanisms of action. In this context, microfluidic models could offer insights into the effects of ginger on monocyte recruitment in a more physiologically relevant context. Overall, ginger extracts represent a potential novel treatment for preventing CVD initiation, but additional studies are necessary to identify the active molecules in these fractions.

T-Cell Metabolic Reprogramming in Atherosclerosis

Atherosclerosis is a key pathological basis for cardiovascular diseases, significantly influenced by T-cell-mediated immune responses. T-cells differentiate into various subtypes, such as pro-inflammatory Th1/Th17 and anti-inflammatory Th2/Treg cells. The imbalance between these subtypes is critical for the progression of atherosclerosis (AS). Recent studies indicate that metabolic reprogramming within various microenvironments can shift T-cell differentiation towards pro-inflammatory or anti-inflammatory phenotypes, thus influencing AS progression. This review examines the roles of pro-inflammatory and anti-inflammatory T-cells in atherosclerosis, focusing on how their metabolic reprogramming regulates AS progression and the associated molecular mechanisms of mTOR and AMPK signaling pathways.

Comprehensive Insights into Keloid Pathogenesis and Advanced Therapeutic Strategies

Keloid scars, characterized by abnormal fibroproliferation and excessive extracellular matrix (ECM) production that extends beyond the original wound, often cause pruritus, pain, and hyperpigmentation, significantly impacting the quality of life. Keloid pathogenesis is multifactorial, involving genetic predisposition, immune response dysregulation, and aberrant wound-healing processes. Central molecular pathways such as TGF-β/Smad and JAK/STAT are important in keloid formation by sustaining fibroblast activation and ECM deposition. Conventional treatments, including surgical excision, radiation, laser therapies, and intralesional injections, yield variable success but are limited by high recurrence rates and potential adverse effects. Emerging therapies targeting specific immune pathways, small molecule inhibitors, RNA interference, and mesenchymal stem cells show promise in disrupting the underlying mechanisms of keloid pathogenesis, potentially offering more effective and lasting treatment outcomes. Despite advancements, further research is essential to fully elucidate the precise mechanisms of keloid formation and to develop targeted therapies. Ongoing clinical trials and research efforts are vital for translating these scientific insights into practical treatments that can markedly enhance the quality of life for individuals affected by keloid scars.