NOX2 inhibition stabilizes vulnerable plaques by enhancing macrophage efferocytosis via MertK/PI3K/AKT pathway

Effect of xylitol on low‑density lipoprotein‑stimulated oxidative stress in THP‑1 cells

Atherosclerosis (AS) is a chronic inflammatory disease caused by oxidative stress and the oxidation of low‑density lipoprotein (LDL). Xylitol, a widely used sugar substitute, has antioxidant potential; however, its effects on LDL‑induced oxidative stress in AS remain unclear. Using western blot, reverse transcription‑quantitative PCR, flow cytometry and so on, the present study investigated the role of xylitol in mitigating oxidative stress induced by high levels of LDL in Tohoku Hospital Pediatrics‑1 (THP‑1) human monocytic cell line), a model for studying AS. Xylitol significantly alleviated high LDL‑induced oxidative stress in THP‑1 cells and decreased reactive oxygen species levels, malondialdehyde content and the expression of NADPH oxidase family enzymes. Concurrently, xylitol enhanced the activity and expression of superoxide dismutase and increased the glutathione levels. Mechanistically, xylitol activated the nuclear factor erythroid 2‑related factor 2 (Nrf2)/heme oxygenase‑1 (HO‑1) axis by increasing the NADPH/NADP+ ratio via the regulation of the pentose phosphate pathway via the Nrf2 transcription factor. This led to a decrease in LDL oxidative modification in THP‑1 cells (Figs. 6,7). Overall, xylitol attenuates high LDL level‑induced oxidative stress in THP‑1 cells by modulating the Nrf2‑mediated pentose phosphate pathway and activating the Nrf2/HO‑1 axis, highlighting its potential for the prevention and treatment of AS.

Defining "Vulnerable" in coronary artery disease: predisposing factors and preventive measures

The likelihood of a plaque to cause an acute coronary syndrome (ACS) depends on several factors, both lesion- and patient-related. One of the most investigated and established contributing factors is the presence of high-risk or "vulnerable plaque" characteristics, which have been correlated with increased incidence of major adverse cardiovascular events (MACE). The recognition, however, that a significant percentage of vulnerable plaques do not result in causing clinical events has led the scientific community towards the more multifaceted concept of "vulnerable patients". Incorporating the morphological features of an atherosclerotic plaque into its hemodynamic surroundings can better predict the chance of its disruption, as altered fluid dynamics play a significant role in plaque destabilization. The advances in coronary imaging and the field of computational fluid dynamics (CFD) can contribute to develop more accurate lesion- and patient-related ACS prediction models that take into account both the morphology of a plaque and the forces applied upon it. The aim of this review is to provide the latest data regarding the aforementioned predictive factors as well as relevant preventive measures.

NADPH oxidase 2 inhibitor GSK2795039 prevents against cardiac remodeling after MI through reducing oxidative stress and mitochondrial dysfunction

Myocardial infarction (MI) is the leading cause of mortality in cardiovascular diseases and continues to pose a substantial challenge in clinical management, despite the availability of guideline-directed medical therapy. The present study aimed to investigate the potential protective effects of the NADPH oxidase inhibitor (NI) GSK2795039 on cardiac remodeling following MI, and to elucidate the underlying mechanisms involved. We established the MI model by ligating the left anterior descending artery in mice. Additionally, we replicated this model in vitro by stimulating H9C2 cells with levarterenol (LN). The assessment of cardiac function, cardiomyocyte size, apoptosis, infarct size, and mitochondrial structure was conducted utilizing echocardiography, WGA staining, TUNEL assay, Masson's staining, and electron microscopy, respectively. The investigation of this mechanism utilized colorimetry, Western blotting, flow cytometry, and RT-PCR techniques. Compared to mice with MI or H9C2 cells stimulated by LN, NI treatment significantly improved cardiac dysfunction and hypertrophy. It also resulted in a reduction of cardiomyocyte size and apoptosis, decreased infarct size, alleviated mitochondrial structural damage, lowered levels of malondialdehyde and NOX2, diminished ROS production while inhibiting NOX activity, and enhanced the activities of T-SOD, GSH-PX, as well as mitochondrial complexes I-V. Additionally, it led to an increase in mitochondrial OCR, ATP levels and MMP. These findings indicate that GSK2795039 can mitigate oxidative stress and mitochondrial dysfunction through the inhibition of NOX2, thereby providing a cardioprotective effect against cardiac remodeling induced by MI. This suggests that GSK2795039 may possess therapeutic potential for patients following MI.

Aquaporin 9: Exacerbation of Vulnerable Carotid Plaque Formation

Aquaporin 9 (AQP9) expression is significantly elevated in vulnerable carotid plaque (VCP). Hence, we probed the mechanism of AQP9 in VCP formation. The VCP model was established in ApoE-/- C57BL/6 mice. Dataset GSE163154 was analyzed by R software. Human aortic endothelial cells (HAECs) were incubated with 50 µg/mL oxidized low-density lipoprotein (ox-LDL) and 20 mM l-(+)-lactic acid for 24 h. Mice (AQP9 overexpression plasmid) and HAECs (AQP9 overexpression/dynamin-related protein 1 [DRP1] silencing plasmids) were infected by lentivirus. Mouse plasma lipid level was estimated. The histopathological condition of model mice was observed by oil red lipid staining, hematoxylin-eosin (H&E) staining, and Masson staining. Levels of AQP9 and DRP1 in model mice and HAECs were quantified by quantitative real-time polymerase chain reaction (qRT-PCR). Levels of AQP9, DRP1, and mitochondrial fission-/endothelium-mesenchymal transition (EndMT)-related factors in model mice and HAECs were assayed by western blot. Lactate level in model mice was detected. Promoter histone lactylation level of DRP1 was measured by chromatin immunoprecipitation (ChIP). Behaviors of HAECs were tested by cell counting kit-8 (CCK-8), colony formation test, and scratch test. AQP9 was highly expressed in intraplaque hemorrhage patients. AQP9 overexpression promoted levels of DRP1, lactate, histone lactylation, mitochondrial fission factor, vimentin, and N-cadherin, while inhibiting vascular endothelial (VE)-cadherin level and plaque stability in model mice and facilitating viability, proliferation, and migration of HAECs. DRP1 silencing reversed the impacts of AQP9 overexpression on cell viability, proliferation, migration, and levels of mitochondrial fission-/EndMT-related factors in HAECs. AQP9 enhances DRP1-mediated mitochondrial fission by lactate and thus promotes EndMT to exacerbate the VCP formation.

Suppression of NOX2-Derived Reactive Oxygen Species (ROS) Reduces Epithelial-to-MesEnchymal Transition Through Blocking SiO2-Regulated JNK Activation

(1) Background: Silicosis, a chronic lung fibrosis disorder triggered by the accumulation of silica dust in the deep lung regions, is characterized by intricate molecular mechanisms. Among these, the NOX2 (NADPH oxidase 2) and JNK (C-Jun N-terminal kinase) signaling pathways play pivotal roles in the progression of pulmonary fibrosis. Despite their significance, the precise mechanisms underlying the crosstalk between these pathways remain largely unexplored. (2) Methods: To unravel these interactions, we examined the interplay between JNK and NOX2 in human epithelial cells subjected to silica dust exposure through in vivo assays, followed by validation using single-cell sequencing. Our findings consistently revealed elevated expression levels of key components from both the JNK signaling pathway and NOX2 in the lungs of silicosis-induced mice and silica-treated human epithelial cells. (3) Results: Notably, the activation of these pathways was linked to increased ROS (reactive oxygen species) production, elevated levels of profibrogenic factors, and diminished cell proliferation in silica-exposed human lung epithelial cells. Further mechanistic analyses demonstrated that JNK signaling amplifies NOX2 expression and ROS production induced by silica exposure, while treatment with the JNK inhibitor SP600125 mitigates these effects. Conversely, overexpression of NOX2 enhanced silica-induced JNK activation and the expression of epithelial-mesenchymal transition (EMT)-related factors, whereas NOX2 knockdown exerted the opposite effect. These results suggest a positive feedback loop between JNK and NOX2 signaling, which may drive EMT in lung epithelial cells following silica exposure. (4) Conclusions: This reciprocal interaction appears to play a critical role in lung epithelial cell damage and the pathogenesis of silicosis, shedding light on the molecular mechanisms underlying profibrogenic disease and offering potential avenues for therapeutic intervention.

LGR6 modulates intervertebral disc degeneration through regulation of macrophage efferocytosis

BACKGROUND AND OBJECTIVES

Intervertebral disc degeneration (IVDD) is a leading cause of chronic low back pain, characterized by extracellular matrix (ECM) degradation, excessive inflammation activation, and increased cell apoptosis. LGR6, a receptor known for its role in tissue regeneration, has recently been implicated in modulating macrophage efferocytosis, a process critical for clearing apoptotic cells and maintaining tissue homeostasis. This study aimed to investigate the role of LGR6 in regulating IVDD progression and to focus on its impact on macrophage efferocytosis, ECM regulation, and apoptosis in nucleus pulposus cells (NPCs).

METHODS

A comprehensive bioinformatic analysis was performed using datasets GSE56081 and GSE70362 to identify differentially expressed genes (DEGs) and gene modules associated with IVDD. Principal component analysis (PCA), volcano plots, and hierarchical clustering were utilized to assess gene expression patterns. Weighted Gene Co-Expression Network Analysis (WGCNA) was employed to identify gene modules correlated with IVDD, and integrative analysis pinpointed key genes and pathways. In vitro, LGR6 expression in macrophages was manipulated through shRNA interference and overexpression assay. The effects of LGR6 on macrophage efferocytosis, ECM synthesis, and apoptosis were assessed. An in vivo IVDD model was established in mice via disc puncture to evaluate the impact of LGR6 modulation on disc degeneration.

RESULTS

Bioinformatic analysis revealed distinct gene expression profiles between control and IVDD samples, with key gene modules identified by WGCNA showing strong correlations with IVDD. Integrative analysis highlighted critical pathways, including ECM-receptor interaction and efferocytosis, that are potentially regulated by several key genes including SERPINA1, THBS4, ELMO1, LGR6, and ITGB8. Of those genes, LGR6 appeared to be the gene most closely related to IVDD severity. In addition, the mRNA level and protein level of LGR6 in macrophages co-cultured with IL-1β-treated NPCs were raised significantly, compared to the control group. In vitro, LGR6 overexpression enhanced macrophage efferocytosis. Meanwhile, under co-culturing with IL-1β-treated NPCs, LGR6 overexpression in macrophages led to increased expression of ECM components such as COL2A1 and decreased expression of matrix-degrading enzymes like MMP13, indicating a protective effect against matrix degradation. Additionally, LGR6 overexpression inhibited IL-1β-induced apoptosis in NPCs by upregulating anti-apoptotic proteins (BCL2) and downregulating pro-apoptotic markers (cleaved caspase 3 and BAX). Conversely, LGR6 knockdown impaired macrophage efferocytosis and exacerbated NPCs apoptosis. In the mouse IVDD model, promoting efferocytosis resulted in improved ECM integrity and reduced apoptosis; and suppressing efferocytosis caused opposite effect, further supporting the protective role of LGR6-related efferocytosis in IVDD.

CONCLUSIONS

LGR6 significantly contributes to the protective effects on IVDD by modulating macrophage efferocytosis, enhancing ECM synthesis, and reducing apoptosis in NPCs. These findings highlight that LGR6 could be a promising therapeutic target for IVDD, with its dual role in regulating immune responses and preserving tissue integrity. Future studies are necessary to evaluate the clinical potential of LGR6-based therapies in treating degenerative disc diseases.

Impairment of endothelial MerTK accelerates atherosclerosis development

Objective

Atherosclerosis is a chronic inflammatory disease primarily affecting large arteries and is the leading cause of cardiovascular disease. MER proto-oncogene tyrosine kinase (MerTK) plays a key role in regulating efferocytosis, a process for the clearance of apoptotic cells. This study investigates the specific contribution of endothelial MerTK to atherosclerosis development.

Approach and Results

Big data analytics, human microarray analyses, proteomics, and a unique mouse model with MerTK deficiency in endothelial cells (MerTK flox/flox Tie2 Cre ) were utilized to elucidate the role of endothelial MerTK in atherosclerosis development. Our big data analytics, encompassing approximately 98881 cross analyses including 234 analyses for atherosclerosis in the aortic arch, along with human microarray data, reveal that inflammatory responses play a predominant role in atherosclerosis. In vivo, MerTK flox/flox Tie2 Cre mice and the littermate control MerTK flox/flox mice were used to establish an early stage of atherosclerosis model through a high-fat diet combined with AAV8-PCSK9 treatment. Consistent with big data analytics and human microarray analyses, our proteomics data showed that MerTK flox/flox Tie2 Cre mice demonstrated significantly enhanced proinflammatory signaling, mitochondrial dysfunction, and activated mitogen-activated protein kinase (MAPK) pathway compared to that of MerTK flox/flox mice. Endothelial MerTK deficiency induces endothelial dysfunction (enhanced endothelial inflammation, mitochondrial dysfunction, and activation of NADPH oxidases and MAPK signaling pathways) and subsequently causes smooth muscle cell (SMC) phenotypic alterations, ultimately promoting atherosclerosis development.

Conclusions

Our findings provide strong evidence that endothelial MerTK impairment serves as a novel mechanism in promoting atherosclerosis development.

Immunomodulatory Effects of Symplectoteuthis oualaniensis Protamine and Its PEG Derivative on Macrophages: Involvement of PI3K/Akt Signaling, Redox Regulation, and Cell Cycle Modulation

Protamine is a promising marine-derived bioactive compound that is highly arginine-rich and has demonstrated unique advantages in medical and biological research. This study, for the first time, investigates the molecular mechanisms underlying the immunomodulatory effects of Salmon Protamine Sulfate (SPS), Symplectoteuthis oualaniensis Protamine (SOP), and its polyethylene glycol (PEG) derivative (SOP-PEG) on RAW264.7 macrophages. The results demonstrate that both SOP and SOP-PEG significantly enhance the proliferation of RAW264.7 cells by promoting the secretion of pro-inflammatory cytokines and nitric oxide (NO), increasing ROS production, and improving antioxidant capacity, in comparison to SPS. Elevated ROS levels play a crucial role in enhancing macrophage immune activity, while the enhanced antioxidant defense mechanisms help maintain redox homeostasis and protect against oxidative stress-induced cellular damage. A Western blot analysis reveals that SOP and SOP-PEG notably regulate the expression of key proteins associated with the PI3K/Akt signaling pathway and anti-apoptotic mechanisms. Furthermore, a flow cytometry analysis indicates a significant increase in the G2/M-phase cell population in the treatment groups, which is corroborated by Western blot data showing alterations in critical regulatory proteins. Notably, SOP-PEG exhibits the strongest effects in regulating macrophage immune activity, which can be attributed to the enhanced stability and prolonged bioactivity resulting from the PEGylation of SOP. This comprehensive study reveals how SOP and SOP-PEG enhance macrophage immune function through multiple mechanisms, including PI3K/Akt activation, redox regulation, and cell cycle modulation. It provides valuable insights and a theoretical foundation for their potential applications in immunotherapy and immune regulation.

Macrophage KDM2A promotes atherosclerosis via regulating FYN and inducing inflammatory response

Macrophage inflammatory response is the key driver in atherosclerosis development. However, transcriptional remodeling of macrophage inflammatory response remains largely unknown. In this study, transcriptional regulatory networks were constructed from human plaque microarray datasets. Differential analysis and subsequent machine learning algorithms were used to identify key transcriptional regulons. Multiple immune cell inference methods (including CIBERSORT, ssGSEA, MCP-counter, and xCell), single-cell RNA-seq of human plaques and immunofluorescence of human and mouse plaque samples reveal that the macrophage-specific transcriptional regulator, KDM2A, is critical for inflammatory response. Diagnostic analyses validate KDM2A expression in peripheral monocytes/macrophages is an excellent predictor of atherosclerosis development and progression. RNA-seq of mouse bone marrow-derived macrophages under oxidized low-density lipoprotein stimulation reveal KDM2A knockdown significantly represses pro-inflammatory, oxidative, and lipid uptake pathways. In vitro experiments confirmed KDM2A activates inflammation, oxidative stress and lipid accumulation in macrophages. Mechanistically, FYN was identified as a direct target of KDM2A by chromatin immunoprecipitation followed by sequencing and qPCR analysis. Specific inhibition of FYN restored the inflammatory response, oxidative stress, and intracellular lipid accumulation after transfection with KDM2A overexpression plasmid. Importantly, macrophage-specific knockdown of KDM2A in ApoE-/- mice fed a high-fat diet apparently attenuated plaque progression. Furthermore, the genetic association of KDM2A with atherosclerosis was validated by Mendelian randomization and colocalization analysis. A group of small molecules with the potential to target KDM2A has been identified through virtual screening, offering promising strategies for atherosclerosis treatment. The current study provides the novel role of KDM2A in macrophage inflammatory response of atherosclerosis through transcriptional regulation of FYN.

Sulforaphane promotes diabetic wound healing by regulating macrophage efferocytosis and polarization

BACKGROUND

Delayed wound healing frequently occurs as a complication of diabetes. Diabetic wounds that are difficult to heal are associated with chronic, persistent inflammation, characterized by impaired efferocytosis and a sustained pro-inflammatory state of macrophages at the wound site. Sulforaphane (SFN), a bioactive compound found in cruciferous vegetables, possesses anti-inflammatory and antioxidant activities. Numerous studies have shown that SFN can inhibit various inflammatory diseases such as atherosclerosis and psoriasis; however, its potential in treating diabetic wounds remains unknown.

PURPOSE

This study investigates the effects and potential mechanisms of SFN on diabetic wound healing.

METHODS

Network pharmacology approaches were employed to identify potential targets of SFN for diabetic wound treatment. Additionally, an STZ-induced diabetic mouse model (C57/B6) was used in in vivo studies to examine SFN's impact on diabetic wound healing. Simultaneously, immunofluorescence staining, immunohistochemical staining, Western blotting, and qPCR analysis were employed to detect phenotypes associated with macrophage efferocytosis and M2 polarization. Subsequently, the mechanism underlying SFN treatment was explored through in vitro experiments utilizing the THP-1 human monocyte cell line.

RESULTS

The results demonstrated that topical SFN application accelerated wound healing in diabetic mice, partly through the enhancement of impaired macrophage efferocytosis and the promotion of M2 macrophage polarization, thereby reducing the inflammatory response at the wound site. SFN promoted the phagocytosis of apoptotic Jurkat cells by THP-1 differentiated macrophages, reducing the resulting inflammatory response. Mechanistic studies revealed that SFN promotes macrophage efferocytosis by activating nuclear factor E2-related factor 2 (Nrf2), leading to upregulation of heme oxygenase 1 (HO-1) expression and subsequent enhancement of mer proto-oncogene tyrosine kinase (MERTK), a recognition receptor for efferocytosis. Furthermore, SFN enhanced macrophage polarization toward the M2 phenotype and reduced the lipopolysaccharide (LPS)-induced inflammatory response in vitro.

CONCLUSION

These data suggest that SFN could serve as an effective adjunct or novel therapeutic agent for treating chronic non-healing wounds in diabetes.

Emerging Contaminants: An Important But Ignored Risk Factor for Psoriasis

Industrialization and modernization have changed the environment. A group of emerging contaminants (ECs) has been defined recently. Psoriasis, whose incidence has increased in recent years, is a relapsing immune-mediated disease carrying a heavy disease burden. The erythematous scaly plaque is a typical symptom and occurs on several parts of the body. In addition, psoriasis has many comorbidities, such as psoriatic arthritis, diabetes, and depression, damaging the quality of life of patients. IL-17, IL-12, IL-23, and TNF-alpha are important related cytokines. ECs can influence psoriasis through the immune system and inflammatory responses. Specific mechanisms include increasing pro-inflammatory cytokines such as TNF-α and IL-17, and activating immune cells such as macrophages. And for psoriasis patients, it is suggested to reduce the exposure of most ECs. However, the complex mechanisms involved have not been discussed together and concluded. In this review, we summarize the relationship between ECs and psoriasis, focusing on the immune system, especially the immune cells and cytokines. These results can help guide clinical treatment and long-term management of psoriasis.

Oxidative stress mediated by the NOX2/ROS/NF-κB signaling axis is involved in rosacea

Rosacea is a chronic inflammatory cutaneous disease characterized by a multifaceted pathogenesis. Extensive research has demonstrated that oxidative stress plays a pivotal role in the etiology of rosacea, mediating vascular alterations and inflammation cascades via the generation of reactive oxygen species (ROS). Nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) possesses the capacity to synthesize ROS and exhibits a strong correlation with diverse inflammatory processes. However, the effects of NOX2 in rosacea are unknown. Our findings revealed that NOX2 was highly expressed in rosacea. Inhibition of NOX2 improved markedly rosacea-like manifestations, encompassing reduced skin erythema and downregulated expression of pro-inflammatory cytokines and chemokines. Additionally, knockdown NOX2 in HaCaT keratinocytes significantly rescues TNF-α-induced oxidative stress and inflammation. Our study further elucidated that inhibition of NOX2 suppressed NF-κB activation in LL37-induced skin and LL37/ TNF-α-induced HaCaT keratinocytes. Our results demonstrate that NOX2 plays a proinflammatory role in rosacea by regulating the NF-κB signaling pathway.

The various roles of TREM2 in cardiovascular disease

Triggering receptor expressed on myeloid cells-2 (TREM2) is a transmembrane immune receptor that is expressed mainly on macrophages. As a pathology-induced immune signaling hub, TREM2 senses tissue damage and activates immune remodeling in response. Previous studies have predominantly focused on the TREM2 signaling pathway in Alzheimer's disease, metabolic syndrome, and cancer. Recent research has indicated that TREM2 signaling is also activated in various cardiovascular diseases. In this review, we summarize the current understanding and the unanswered questions regarding the role of TREM2 signaling in mediating the metabolism and function of macrophages in atherosclerosis and various models of heart failure. In the context of atherosclerosis, TREM2 signaling promotes foam cell formation and is crucial for maintaining macrophage survival and plaque stability through efferocytosis and cholesterol efflux. Recent studies on myocardial infarction, sepsis-induced cardiomyopathy, and hypertensive heart failure also implicated the protective role of TREM2 signaling in cardiac macrophages through efferocytosis and paracrine functions. Additionally, we discuss the clinical significance of elevated soluble TREM2 (sTREM2) in cardiovascular disease and propose potential therapies targeting TREM2. The overall aim of this review is to highlight the various roles of TREM2 in cardiovascular diseases and to provide a framework for therapeutic strategies targeting TREM2.

The efferocytosis dilemma: how neutrophil extracellular traps and PI3K/Rac1 complicate diabetic wound healing

AIMS/HYPOTHESIS

The resolution of apoptotic cells (ACs) is crucial for wound healing and tissue remodeling and is often impaired by persistent inflammation. This study aimed to elucidate the impact of neutrophil extracellular traps (NETs) on diabetic wound healing by targeting the phosphoinositide 3-kinase/Ras-related C3 botulinum toxin substrate 1 (PI3K/Rac1) signaling pathway, which is pivotal for macrophage efferocytosis.

METHODS

A streptozotocin-induced diabetic mouse model was used to assess the impact of NETs on efferocytosis in vivo. The effects of NETs on macrophage efferocytosis and wound healing were evaluated using specific inhibitors and agonists targeting the PI3K/Rac1 pathway. In vitro, macrophages from diabetic wounds or cell lines (Raw264.7) were treated with NETs and a panel of pharmacological agents of the PI3K/Rac1 pathway to evaluate macrophage efferocytosis.

RESULTS

NETs were found to inhibit macrophage efferocytosis, resulting in delayed clearance of ACs that accumulate within the wounds. Inhibition of NET formation in diabetic mice rescued impaired efferocytosis, accompanied by reactivation of PI3K and Rac1 in macrophages. Moreover, pharmacological agents targeting the PI3K/Rac1 pathway restored NETs-induced impairment in efferocytosis, leading to rapid wound healing. Raw264.7 cells exhibited elevated activation levels of PI3K and Rac1 when co-cultured with ACs in vitro. Nevertheless, this signaling activation was inhibited when cultured in a NETs-conditioned medium, leading to attenuated efferocytosis.

CONCLUSIONS/INTERPRETATION

Targeting NETs and the PI3K/Rac1 pathway emerges as a potential therapeutic strategy to enhance healing in diabetic wounds by promoting macrophage efferocytosis.

The Role of mtDNA Mutations in Atherosclerosis: The Influence of Mitochondrial Dysfunction on Macrophage Polarization

Atherosclerosis is a complex inflammatory process associated with high-mortality cardiovascular diseases. Today, there is a growing body of evidence linking atherosclerosis to mutations of mitochondrial DNA (mtDNA). But the mechanism of this link is insufficiently studied. Atherosclerosis progression involves different cell types and macrophages are one of the most important. Due to their high plasticity, macrophages can demonstrate pro-inflammatory and pro-atherogenic (macrophage type M1) or anti-inflammatory and anti-atherogenic (macrophage type M2) effects. These two cell types, formed as a result of external stimuli, differ significantly in their metabolic profile, which suggests the central role of mitochondria in the implementation of the macrophage polarization route. According to this, we assume that mtDNA mutations causing mitochondrial disturbances can play the role of an internal trigger, leading to the formation of macrophage M1 or M2. This review provides a comparative analysis of the characteristics of mitochondrial function in different types of macrophages and their possible associations with mtDNA mutations linked with inflammation-based pathologies including atherosclerosis.

Identification of critical endoplasmic reticulum stress-related genes in advanced atherosclerotic plaque

Atherosclerosis (AS) is the principal pathological cause of atherosclerotic cardiovascular diseases. Chronic endoplasmic reticulum stress (ERS) has been implicated in AS aetiopathogenesis, but the underlying molecular interactions remain unclear. This study aims to identify the molecular mechanisms of ERS in AS pathogenesis to inform innovative diagnostic approaches and therapeutic targets for managing AS. GSE28829 and GSE43292-human early and advanced carotid atherosclerotic tissue samples-were obtained from the Gene Expression Omnibus database. Endoplasmic reticulum stress-related genes (ERSRGs) were obtained from GeneCards. Differential gene expression and weighted gene co-expression network analyses were conducted to identify genes associated with atherosclerosis, and intersection with ER-related genes revealed three ERSRGs (i.e. CTSB, LYN, and CYBB) associated with advanced atherosclerotic plaque. These three ERSRGs exhibited associations with various immune cells. Additionally, the three ERSRGs were upregulated in human atherosclerotic tissues, mouse models of progressive atherosclerotic lesions, and in vitro macrophage models. In conclusion, this study identified CTSB, LYN, and CYBB as potentially critical ERSRGs associated with advanced atherosclerotic plaque, demonstrating their good diagnostic utility and offering novel insights into the potential pathobiology of AS progression, paving the way for exploring innovative therapeutic targets.

Interplay between energy metabolism and NADPH oxidase-mediated pathophysiology in cardiovascular diseases

Sustained production of reactive oxygen species (ROS) and an imbalance in the antioxidant system have been implicated in the development of cardiovascular diseases (CVD), especially when combined with diabetes, hypercholesterolemia, and other metabolic disorders. Among them, NADPH oxidases (NOX), including NOX1-5, are major sources of ROS that mediate redox signaling in both physiological and pathological processes, including fibrosis, hypertrophy, and remodeling. Recent studies have demonstrated that mitochondria produce more proteins and energy in response to adverse stress, corresponding with an increase in superoxide radical anions. Novel NOX4-mediated modulatory mechanisms are considered crucial for maintaining energy metabolism homeostasis during pathological states. In this review, we integrate the latest data to elaborate on the interactions between oxidative stress and energy metabolism in various CVD, aiming to elucidate the higher incidence of CVD in individuals with metabolic disorders. Furthermore, the correlations between NOX and ferroptosis, based on energy metabolism, are preliminarily discussed. Further discoveries of these mechanisms might promote the development of novel therapeutic drugs targeting NOX and their crosstalk with energy metabolism, potentially offering efficient management strategies for CVD.

Anti-inflammatory effects of MerTK by inducing M2 macrophage polarization via PI3K/Akt/GSK-3β pathway in gout

Mer tyrosine kinase (MerTK) has been found to regulate the secretion of inflammatory factors and exert immunosuppressive effects, but its role in gout remains unclear. In this study, we aimed to clarify the immnue effects of MerTK in gout. MerTK in synovium or serum of gout patients was determined by immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), and real-time quantitative polymerase chain reaction (RT-qPCR). In monosodium urate (MSU)-induced gout mice, the effect of MerTK inhibitor (UNC2250) on inflammation and polarization was also assessed. After inhibition, knockdown or overexpression of MerTK, inflammatory response and polarization level in THP1-derived macrophages were evaluated by RT-qPCR and flow cytometry. Regulation of MerTK inhibitors on mitochondrial function and downstream pathway in THP1-derived macrophages were detected. MerTK in synovium and serum of gout patients were increased. MerTK inhibitor stimulated the inflammation and M1 polarization in MSU-induced gout mice. MerTK inhibition, knock-down, or overexpression affected inflammatory response, polarization and mitochondrial function in vitro in gout model. The PI3K/Akt/GSK-3β pathway was identified to reduce after MerTK inhibition and the relevant results were as expected, validated by knock-down or overexpressing MerTK. In conclusion, MerTK was detected to increase in both gout patients and model. MerTK influenced inflammatory response and polarization markers through PI3K/Akt/GSK-3β pathway. Interfering MerTK/PI3K/Akt/GSK-3β axis may provide a new therapeutic target for gout.

Therapeutic implication of targeting mitochondrial drugs designed for efferocytosis dysfunction

Efferocytosis refers to the process by which phagocytes remove apoptotic cells and related apoptotic products. It is essential for the growth and development of the body, the repair of damaged or inflamed tissues, and the balance of the immune system. Damaged efferocytosis will cause a variety of chronic inflammation and immune system diseases. Many studies show that efferocytosis is a process mediated by mitochondria. Mitochondrial metabolism, mitochondrial dynamics, and communication between mitochondria and other organelles can all affect phagocytes' clearance of apoptotic cells. Therefore, targeting mitochondria to modulate phagocyte efferocytosis is an anticipated strategy to prevent and treat chronic inflammatory diseases and autoimmune diseases. In this review, we introduced the mechanism of efferocytosis and the pivoted role of mitochondria in efferocytosis. In addition, we focused on the therapeutic implication of drugs targeting mitochondria in diseases related to efferocytosis dysfunction.

Mechanisms and treatment of atherosclerosis: focus on macrophages

Macrophages are the basic mediators and coordinators of various types of chronic inflammation and play a crucial role in the formation and development of atherosclerosis (AS). In the complex microenvironment of atherosclerotic plaques, macrophages of different sources are exposed to different signal stimuli and thus polarized into various subpopulations. Various types of macrophages with predominantly M1 and M2 phenotypes also play different regulatory roles in the initiation and progression of AS. Lipid-lowering drugs, mainly statins, are widely used in clinical practice, but the adverse reactions are obvious and there is a lack of personalized treatment. Emerging targeted macrophage and Traditional Chinese medicine (TCM)-related therapies can regulate the cellular microenvironment, inhibit the polarization of M1 macrophages, and promote the activation of M2 macrophages, providing new ideas for the prevention and treatment of AS.

HuoXueTongFu formula induces M2c macrophages via the MerTK/PI3K/AKT pathway to eliminate NETs in intraperitoneal adhesion in mice

ETHNOPHARMACOLOGICAL RELEVANCE

HuoXueTongFu Formula (HXTF) is a traditional Chinese herbal formula that has been used as a supplement and alternative therapy for intraperitoneal adhesion (IA). However, its specific mechanism of action has not been fully understood.

AIM OF THE STUDY

In surgery, IA presents an inevitable challenge, significantly impacting patients' physical and mental well-being and increasing the financial burden. Our previous research has confirmed the preventive effects of HXTF on IA formation. However, the precise mechanism of its action still needs to be understood.

METHODS

In this study, the IA model was successfully established by using the Ischemic buttons and treated with HXTF for one week with or without Mer Tyrosine Kinase (MerTK) inhibitor. We evaluated the pharmacodynamic effect of HXTF on IA mice. The MerTK/phosphoinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway-associated proteins were detected by Western blotting. Neutrophil extracellular traps (NETs) were detected by immunofluorescence. Macrophage phenotype was assessed by immunohistochemistry and flow cytometry. Inflammatory cytokines were detected by Real Time Quantitative PCR and Western blotting.

RESULTS

HXTF reduced inflammatory response and alleviated IA. HXTF significantly enhanced MerTK expression, increased the number of M2c macrophages, and decreased the formation of NETs. In addition, the MerTK/PI3K/AKT pathway was significantly activated by HXTF. However, after using MerTK inhibitors, the role of HXTF in inducing M2c macrophage through activation of the PI3K/AKT pathway was suppressed and there was no inhibitory effect on NETs formation and inflammatory responses, resulting in diminished inhibition of adhesion.

CONCLUSION

HXTF may improve IA by activating the MerTK/PI3K/AKT pathway to induce M2c polarization, which removes excess NETs and attenuates the inflammatory response.

NADPH Oxidases in Neurodegenerative Disorders: Mechanisms and Therapeutic Opportunities

Significance: The nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzyme family, located in the central nervous system, is recognized as a source of reactive oxygen species (ROS) in the brain. Despite its importance in cellular processes, excessive ROS generation leads to cell death and is involved in the pathogenesis of neurodegenerative disorders. Recent advances: NOX enzymes contribute to the development of neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and stroke, highlighting their potential as targets for future therapeutic development. This review will discuss NOX's contribution and therapeutic targeting potential in neurodegenerative diseases, focusing on PD, AD, ALS, and stroke. Critical issues: Homeostatic and physiological levels of ROS are crucial for regulating several processes, such as development, memory, neuronal signaling, and vascular homeostasis. However, NOX-mediated excessive ROS generation is deeply involved in the damage of DNA, proteins, and lipids, leading to cell death in the pathogenesis of a wide range of diseases, namely neurodegenerative diseases. Future directions: It is essential to understand the role of NOX homologs in neurodegenerative disorders and the pathological mechanisms undergoing neurodegeneration mediated by increased levels of ROS. This further knowledge will allow the development of new specific NOX inhibitors and their application for neurodegenerative disease therapeutics. Antioxid. Redox Signal. 41, 522-541.

Biomarkers That Seem to Have the Greatest Impact on Promoting the Formation of Atherosclerotic Plaque in Current Scientific Research

Atherosclerosis is a chronic inflammatory disease that causes degenerative and productive changes in the arteries. The resulting atherosclerotic plaques restrict the vessel lumen, causing blood flow disturbances. Plaques are formed mainly in large- and medium-sized arteries, usually at bends and forks where there is turbulence in blood flow. Depending on their location, they can lead to various disease states such as myocardial infarction, stroke, renal failure, peripheral vascular diseases, or sudden cardiac death. In this work, we reviewed the literature on the early detection of atherosclerosis markers in the application of photodynamic therapy to atherosclerosis-related diseases. Herein, we described the roles of C-reactive protein, insulin, osteopontin, osteoprotegerin, copeptin, the TGF-β cytokine family, and the amino acid homocysteine. Also, we discuss the role of microelements such as iron, copper, zinc, and Vitamin D in promoting the formation of atherosclerotic plaque. Dysregulation of the administered compounds is associated with an increased risk of atherosclerosis. Additionally, taking into account the pathophysiology of atherosclerotic plaque formation, we believe that maintaining homeostasis in the range of biomarkers mentioned in this article is crucial for slowing down the process of atherosclerotic plaque development and the stability of plaque that is already formed.

In Vivo Fluorescent Labeling of Foam Cell-Derived Extracellular Vesicles as Circulating Biomarkers for In Vitro Detection of Atherosclerosis

Real-time monitoring of the development of atherosclerosis (AS) is key to the management of cardiovascular disease (CVD). However, existing laboratory approaches lack sensitivity and specificity, mostly due to the dearth of reliable AS biomarkers. Herein, we developed an in vivo fluorescent labeling strategy that allows specific staining of the foam cell-derived extracellular vesicles (EVs) in atherosclerotic plaques, which are released into the blood as circulating biomarkers for in vitro detection of AS. This strategy relies on a self-assembled nanoprobe that could recognize foam cells specifically, where the probe is degraded by the intracellular HClO to produce a trifluoromethyl-bearing boron-dipyrromethene fluorophore (termed B-CF3), a lipophilic dye that can be transferred to the exosomal membranes. These circulating B-CF3-stained EVs can be detected directly on a fluorescence spectrometer or microplate reader without resorting to any sophisticated analytical method. This liquid-biopsy format enables early detection and real-time differentiation of lesion vulnerability during AS progression, facilitating effective CVD management.

The Nutritional Intervention of Ingredients from Food Medicine Homology Regulating Macrophage Polarization on Atherosclerosis

The polarization of macrophages plays a crucial regulatory role in a range of physiological and pathological processes involving macrophages. There are numerous concerns with macrophage polarization in atherosclerosis; however, most focus on modulating macrophage polarization to improve the microenvironment, and the mechanism of action remains unknown. In recent years, the advantages of natural and low-toxicity side effects of food medicine homology-derived substances have been widely explored. Few reports have started from ingredients from food medicine homology to regulate the polarization of macrophages so that early intervention can reduce or delay the process of atherosclerosis. This review summarizes the classification of macrophage polarization and related markers in the process of atherosclerosis. It summarizes the regulatory role of ingredients from food medicine homology in macrophage polarization and their possible mechanisms to provide ideas and inspiration for the nutritional intervention in vascular health.