Human atherosclerotic plaque alternative macrophages display low cholesterol handling but high phagocytosis because of distinct activities of the PPARγ and LXRα pathways

ZeXieYin formula alleviates atherosclerosis by inhibiting the MAPK/NF-κB signaling pathway in APOE-/- mice to attenuate vascular inflammation and increase plaque stability

ETHNOPHARMACOLOGICAL RELEVANCE

Zexieyin formula (ZXYF), a traditional Chinese herbal formula recorded in the Huangdi Neijing to have efficacy in relieving spleen dampness and heat accumulation syndrome, which is also the key pathogenesis of atherosclerosis (AS). The efficacy has demonstrated by our previous studies. However, the intrinsic mechanism of ZXYF for treating vascular inflammation and the effect of inflammatory response on plaque are not known. Currently, plaque stabilization is crucial for the prognosis of AS.

AIM OF THE STUDY

Our study mainly focused on the therapeutic effects of ZXYF on high-fat diet (HFD)-induced vascular inflammation and vulnerable plaques (VP) in mice and explored its underlying mechanism.

METHODS AND MATERIALS

Male apolipoprotein E knockout (APOE-/-) mice were fed HFD for 8 weeks to establish a VP model. During this period, the mice were also administered ZXYF, while atorvastatin (ATO) was used as a positive control. Aortic plaque area and morphology were detected by oil red staining and HE staining. Aortic plaque collagen content was detected by Masson staining. M1/M2 type macrophages were detected using immunofluorescence (IF). The study analyzed the levels of inflammation-related cytokines (IL-1β, IL-10, IL-6), MAPK/NF-κB pathway proteins, and NLRP3 inflammasomes (NLRP3, Caspase-1) using Western blot. Additionally, the levels of matrix metalloproteinase (MMP)-2 and MMP-9 and α-smooth muscle actin (α-SMA) in the aorta were analyzed using immunohistochemistry (IHC). The plaque instability index was calculated for each group using the vulnerable plaque formula.

RESULTS

In this study, APOE-/- mice were fed high-fat diet for 8 weeks. The results of oil-red and HE staining indicated a significant increase in the aortic plaque area of the mice, which exhibited a typical VP phenotype. ZXYF and ATO significantly improved AS plaques and prevented plaque rupture. HFD exacerbated vascular inflammation, stimulated macrophage conversion to M1-type through the MAPK/NF-κB signaling pathway, and released pro-inflammatory factors such as interleukin (IL)-1β, IL-1α, and IL-6. These factors activated NLRP3 inflammasome, leading to cellular death. However, ZXYF could reverse this trend and promote the conversion of macrophages to the anti-inflammatory M2 type. The anti-inflammatory effect of ATO was not significant. Moreover, HFD promoted the release of MMP-2 and MMP-9 from macrophages, which degraded plaque collagen, and induced a decrease in plaque SMC content, resulting in a thinning of the plaque fibrous cap. In contrast, ZXYF inhibited the decomposition of plaque collagen and increased the content of plaque smooth muscle cells (SMC) by reducing macrophage secretion of MMPs, thereby stabilizing plaques. Although ATO could reverse the decrease in plaque collagen and SMC content, its effect on MMPs was not significant. Finally, we calculated the vulnerability index to assess the overall risk of the plaque vulnerability phenotype. In line with these findings, ZXYF and ATO were able to effectively reverse the increase in the vulnerability index caused by HFD and lower the risk of adverse cardiovascular events.

CONCLUSION

Our results suggested that ZXYF could reduce inflammation and increase plaque stability by inhibiting the MAPK/NF-κB signaling pathway, which provided a theoretical basis for clinical application and subsequent research.

The role of macrophage polarization in vascular calcification

Vascular calcification is an important factor in the high morbidity and mortality of Cardiovascular and cerebrovascular diseases. Vascular damage caused by calcification of the intima or media impairs the physiological function of the vascular wall. Inflammation is a central factor in the development of vascular calcification. Macrophages are the main inflammatory cells. Dynamic changes of macrophages with different phenotypes play an important role in the occurrence, progression and stability of calcification. This review focuses on macrophage polarization and the relationship between macrophages of different phenotypes and calcification environment, as well as the mechanism of interaction, it is considered that macrophages can promote vascular calcification by releasing inflammatory mediators and promoting the osteogenic transdifferentiation of smooth muscle cells and so on. In addition, several therapeutic strategies aimed at macrophage polarization for vascular calcification are described, which are of great significance for targeted treatment of vascular calcification.

Interactions between macrophage membrane and lipid mediators during cardiovascular diseases with the implications of scavenger receptors

The onset and progression of cardiovascular diseases with the major underlying cause being atherosclerosis, occur during chronic inflammatory persistence in the vascular system, especially within the arterial wall. Such prolonged maladaptive inflammation is driven by macrophages and their key mediators are generally attributed to a disparity in lipid metabolism. Macrophages are the primary cells of innate immunity, endowed with expansive membrane domains involved in immune responses with their signalling systems. During atherosclerosis, the membrane domains and receptors control various active organisations of macrophages. Their scavenger/endocytic receptors regulate the trafficking of intracellular and extracellular cargo. Corresponding influence on lipid metabolism is mediated by their dynamic interaction with scavenger membrane receptors and their integrated mechanisms such as pinocytosis, phagocytosis, cholesterol export/import, etc. This interaction not only results in the functional differentiation of macrophages but also modifies their structural configurations. Here, we reviewed the association of macrophage membrane biomechanics and their scavenger receptor families with lipid metabolites during the event of atherogenesis. In addition, the membrane structure of macrophages and the signalling pathways involved in endocytosis integrated with lipid metabolism are detailed. This article establishes future insights into the scavenger receptors as potential targets for cardiovascular disease prevention and treatment.

Correlation Analysis of Macrophage Distribution and Pathological Features of Carotid Atherosclerotic Plaque

BACKGROUND

Macrophages play an important role in maintaining the chronic inflammatory of atherosclerosis (AS) and are hallmark of atherosclerotic plaques. They differentiate into different subpopulations under the influence of oxidized lipids and cytokines and play different roles in the formation and development of plaque. To explore the differences in the amount and distribution of different macrophage subpopulations around different carotid plaque pathological features in human AS, and based on these results, to explore the correlation between some macrophage subpopulations and AS pathological features.

METHODS

First, we analyzed the single cells RNA-sequence data from the Gene Expression Omnibus DataSets (GSE159677). Second, we investigated the distribution difference of macrophage subpopulations in 61 surgically resected AS plaques by markers staining include CD68, inducible nitric oxide synthase, Arg-1, CD163 and HO-1.

RESULTS

The result of single cells RNA-Sequence analysis showed that there were a large number of macrophages infiltrated in AS and they can be categorized into different subpopulations with different transcriptional features and functions; moreover in different part of AS (calcified AS core versus proximal adjacent), the total number and subpopulation ratios were all different. The result of staining analysis showed that macrophages mainly distributed in some pathological lesions such as necrosis, fibrous tissue degeneration, cholesterol crystallization etc., and different subpopulations were distributed differently in these lesions.

CONCLUSIONS

This study confirmed that macrophages were heavily infiltrated in atherosclerotic plaques, and there existed subtype variability in different pathological lesions; meanwhile, these results suggested that different macrophage subpopulations may contribute differently in different pathological lesions.

An exploratory human study investigating the influence of type 2 diabetes on macrophage phenotype after myocardial infarction

Background

Myocardial infarction (MI) is the primary cause of death in subjects with type 2 diabetes (T2D) and their in-hospital mortality after MI is still elevated compared with those without T2D. Therefore, it is of crucial importance to identify possible mechanisms of worse clinical outcomes and mortality in T2D subjects. Monocyte/macrophage-mediated immune response plays an important role in heart remodelling to limit functional deterioration after MI. Indeed, first pro-inflammatory macrophages digest damaged tissue, then anti-inflammatory macrophages become prevalent and promote tissue repair. Here, we hypothesize that the worse clinical outcomes in patients with T2D could be the consequence of a defective or a delayed polarization of macrophages toward an anti-inflammatory phenotype.

Methods and results

In an exploratory human study, circulating monocytes from male patients with or without T2D at different time-points after MI were in vitro differentiated toward pro- or anti-inflammatory macrophages. The results of this pilot study suggest that the phenotype of circulating monocytes, as well as the pro- and anti-inflammatory macrophage polarization, or the kinetics of the pro- and anti-inflammatory polarization, is not influenced by T2D.

Conclusion

Further studies will be necessary to understand the real contribution of macrophages after MI in humans.

The association and application of sonodynamic therapy and autophagy in diseases

Sonodynamic therapy (SDT) is a new non-invasive treatment method proposed based on photodynamic therapy (PDT). It has advantages such as high precision, strong tissue penetration, minimal side effects, and good patient compliance. With the maturation of nanomedicine, the application of nanosonosensitizers has further propelled the development of SDT. In recent years, people have developed many new types of sonosensitizers and explored the mechanisms of SDT. Among them, the studies about the relationship between autophagy and SDT have attracted increasing attention. After the SDT, cells usually undergo autophagy as a self-protective mechanism to resist external stimuli and reduce cell damage, which is beneficial for the treatment of atherosclerosis (AS), diabetes, and myocardial infarction but counterproductive in cancer treatment. However, under certain treatment conditions, excessive upregulation of autophagy can also promote cell death, which is beneficial for cancer treatment. This article reviews the latest research progress on the relationship between SDT and autophagy in cancers, AS, diabetes, and myocardial infarction. We also discuss and propose the challenges and prospects in enhancing SDT efficacy by regulating autophagy, with the hope of promoting the development of this promising therapeutic approach.

The role and mechanisms of mesenchymal stem cells regulating macrophage plasticity in spinal cord injury

Spinal Cord Injury (SCI) is a devastating neurological disorder comprising primary mechanical injury and secondary inflammatory response-mediated injury for which an effective treatment is still unavailable. It is well known that secondary inflammatory responses are a significant cause of difficulties in neurological recovery. An immune imbalance between M1/M2 macrophages at the sites of injury is involved in developing and progressing the secondary inflammatory response. Recently, Mesenchymal Stem Cells (MSCs) have shown significant therapeutic potential in tissue engineering and regenerative medicine due to their potential multidirectional differentiation and immunomodulatory properties. Accumulating evidence shows that MSCs can regulate the balance of M1/M2 macrophage polarization, suppress downstream inflammatory responses, facilitate tissue repair and regeneration, and improve the prognosis of SCI. This article briefly overviews the impact of macrophages and MSCs on SCI and repair. It discusses the mechanisms by which MSCs regulate macrophage plasticity, including paracrine action, release of exosomes and apoptotic bodies, and metabolic reprogramming. Additionally, the article summarizes the relevant signaling pathways of MSCs that regulate macrophage polarization.

Myeloid BAF60a deficiency alters metabolic homeostasis and exacerbates atherosclerosis

Atherosclerosis, a leading health concern, stems from the dynamic involvement of immune cells in vascular plaques. Despite its significance, the interplay between chromatin remodeling and transcriptional regulation in plaque macrophages is understudied. We discovered the reduced expression of Baf60a, a component of the switch/sucrose non-fermentable (SWI/SNF) chromatin remodeling complex, in macrophages from advanced plaques. Myeloid-specific Baf60a deletion compromised mitochondrial integrity and heightened adhesion, apoptosis, and plaque development. BAF60a preserves mitochondrial energy homeostasis under pro-atherogenic stimuli by retaining nuclear respiratory factor 1 (NRF1) accessibility at critical genes. Overexpression of BAF60a rescued mitochondrial dysfunction in an NRF1-dependent manner. This study illuminates the BAF60a-NRF1 axis as a mitochondrial function modulator in atherosclerosis, proposing the rejuvenation of perturbed chromatin remodeling machinery as a potential therapeutic target.

QiShenYiQi pill inhibits atherosclerosis by promoting reverse cholesterol transport PPARγ-LXRα/β-ABCA1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

QiShenYiQi pill (QSYQ), a Chinese compound medicine, originate from BuYangHuanWu decoction in the Qing dynasty, and has been used to treat ischemic cardiovascular diseases for more than two hundred years in China. Multi-central randomized double-blind controlled studies have proved that QSYQ has similar efficacy as enteric coated aspirin in the secondary prevention of myocardial infarction.

AIM OF STUDY

The aim of study was to explore the effect of QSYQ on reverse cholesterol transport (RCT) pathway during atherosclerosis.

MATERIALS AND METHODS

Eight-week-old male apoE-/- mice (on the gene background of C57BL/6J) were fed with a high-fat western diet and treated with low dose and high dose of QSYQ, as well as the positive control agent, liver X receptor-α (LXR-α) agonist GW3965. Eight weeks later, mice were sacrificed and the aorta was collected for atherosclerotic analysis. The aortic root was stained with Oil red O to evaluate the area of atherosclerotic lesion, and stained with immunohistochemistry to analyze the intra-plaque component and RCT protein in atherosclerotic plaque. The thoracic aorta was used to detect differentially expressed genes by comparative transcriptome RNA-seq and the protein expression of RCT pathway by western blotting.

RESULTS

After eight weeks of treatment, we found that both of QSYQ and LXR-α agonist reduced atherosclerotic plaque area significantly, and decreased the intra-plaque component, including the lipid, the smooth muscle cell and the macrophage. Compared with the control group, there were 49 differentially expressed genes in low-dose QSYQ group, including 21 up-regulated genes and 28 down-regulated genes. The results of GO and KEGG analysis showed that the differentially expressed genes mainly concentrated in the negative regulation of lipid biosynthesis, positive regulation of lipid metabolism, cell response to lipids, negative regulation of lipid storage, fatty acid degradation, and glycerol ester metabolism. Both of QSYQ and LXR-α agonist reduced the protein expression of CD36 and increased the protein expression of PPARγ-LXRα/β-ABCA1 in atherosclerotic plaque.

CONCLUSION

The anti-atherosclerotic mechanism of QSYQ was involved in inhibiting lipid phagocytosis and promoting reverse cholesterol transport, therefore reducing lipid deposition and inflammatory cells in plaque.

Reno- and cardioprotective molecular mechanisms of SGLT2 inhibitors beyond glycemic control: from bedside to bench

Large placebo-controlled clinical trials have shown that sodium-glucose cotransporter-2 inhibitors (SGLT2i) delay the deterioration of renal function and reduce cardiovascular events in a glucose-independent manner, thereby ultimately reducing mortality in patients with chronic kidney disease (CKD) and/or heart failure. These existing clinical data stimulated preclinical studies aiming to understand the observed clinical effects. In animal models, it was shown that the beneficial effect of SGLT2i on the tubuloglomerular feedback (TGF) improves glomerular pressure and reduces tubular workload by improving renal hemodynamics, which appears to be dependent on salt intake. High salt intake might blunt the SGLT2i effects on the TGF. Beyond the salt-dependent effects of SGLT2i on renal hemodynamics, SGLT2i inhibited several key aspects of macrophage-mediated renal inflammation and fibrosis, including inhibiting the differentiation of monocytes to macrophages, promoting the polarization of macrophages from a proinflammatory M1 phenotype to an anti-inflammatory M2 phenotype, and suppressing the activation of inflammasomes and major proinflammatory factors. As macrophages are also important cells mediating atherosclerosis and myocardial remodeling after injury, the inhibitory effects of SGLT2i on macrophage differentiation and inflammatory responses may also play a role in stabilizing atherosclerotic plaques and ameliorating myocardial inflammation and fibrosis. Recent studies suggest that SGLT2i may also act directly on the Na+/H+ exchanger and Late-INa in cardiomyocytes thus reducing Na+ and Ca2+ overload-mediated myocardial damage. In addition, the renal-cardioprotective mechanisms of SGLT2i include systemic effects on the sympathetic nervous system, blood volume, salt excretion, and energy metabolism.

A Comparative Study of Ultrasmall Calcium Carbonate Nanoparticles for Targeting and Imaging Atherosclerotic Plaque

Atherosclerosis is a complex disease that can lead to life-threatening events, such as myocardial infarction and ischemic stroke. Despite the severity of this disease, diagnosing plaque vulnerability remains challenging due to the lack of effective diagnostic tools. Conventional diagnostic protocols lack specificity and fail to predict the type of atherosclerotic lesion and the risk of plaque rupture. To address this issue, technologies are emerging, such as noninvasive medical imaging of atherosclerotic plaque with customized nanotechnological solutions. Modulating the biological interactions and contrast of nanoparticles in various imaging techniques, including magnetic resonance imaging, is possible through the careful design of their physicochemical properties. However, few examples of comparative studies between nanoparticles targeting different hallmarks of atherosclerosis exist to provide information about the plaque development stage. Our work demonstrates that Gd (III)-doped amorphous calcium carbonate nanoparticles are an effective tool for these comparative studies due to their high magnetic resonance contrast and physicochemical properties. In an animal model of atherosclerosis, we compare the imaging performance of three types of nanoparticles: bare amorphous calcium carbonate and those functionalized with the ligands alendronate (for microcalcification targeting) and trimannose (for inflammation targeting). Our study provides useful insights into ligand-mediated targeted imaging of atherosclerosis through a combination of in vivo imaging, ex vivo tissue analysis, and in vitro targeting experiments.

Silica nanoparticles promoted pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling

Experimental evidence has pointed out silica nanoparticles (SiNPs) possessing a proatherogenic capability. However, the interplay between SiNPs and macrophages in the pathogenesis of atherosclerosis was poorly understood. Here, we demonstrated SiNPs could promote macrophage adhesion to endothelial cells, accompanied by elevated Vcam1 and Mcp1. Upon SiNPs stimuli, macrophages manifested enhanced phagocytic activity and a pro-inflammatory phenotype, as reflected by the transcriptional determination of M1/M2-related biomarkers. In particular, our data certified the increased macrophage M1 subset facilitated more lipid accumulation and resultant foam cell transformation in comparison to the M2 phenotype. More importantly, the mechanistic investigations revealed ROS-mediated PPARγ/NF-κB signaling was a key contributor to the above phenomena. That was, SiNPs caused ROS accumulation in macrophages, resulting in the deactivation of PPARγ, nuclear translocation of NF-κB, ultimately contributing to macrophage phenotype shift toward M1 and foam cell transformation. Collectively, we first revealed SiNPs facilitated pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling. These data would provide new insight into the atherogenic property of SiNPs in a macrophage model.

Macrophage death in atherosclerosis: potential role in calcification

Cell death is an important aspect of atherosclerotic plaque development. Insufficient efferocytosis of death cells by phagocytic macrophages leads to the buildup of a necrotic core that impacts stability of the plaque. Furthermore, in the presence of calcium and phosphate, apoptotic bodies resulting from death cells can act as nucleation sites for the formation of calcium phosphate crystals, mostly in the form of hydroxyapatite, which leads to calcification of the atherosclerotic plaque, further impacting plaque stability. Excessive uptake of cholesterol-loaded oxidized LDL particles by macrophages present in atherosclerotic plaques leads to foam cell formation, which not only reduces their efferocytosis capacity, but also can induce apoptosis in these cells. The resulting apoptotic bodies can contribute to calcification of the atherosclerotic plaque. Moreover, other forms of macrophage cell death, such as pyroptosis, necroptosis, parthanatos, and ferroptosis can also contribute by similar mechanisms to plaque calcification. This review focuses on macrophage death in atherosclerosis, and its potential role in calcification. Reducing macrophage cell death and/or increasing their efferocytosis capacity could be a novel therapeutic strategy to reduce the formation of a necrotic core and calcification and thereby improving atherosclerotic plaque stability.

Shear stress and plaque microenvironment induce heterogeneity: A multiscale microenvironment evolution model

BACKGROUND

Both clinical images and in vivo observations have demonstrated the heterogeneity in atherosclerotic plaque composition. However, the quantitative mechanisms that contribute to the heterogeneity, such as the wall shear stress (WSS) and the interplays among microenvironmental factors are still unclear.

METHODS

We develop a multiscale model coupling computational fluid dynamics, interactions of microenvironmental factors and evolutions of cellular behaviors to investigate the formation of plaque heterogeneity in a three-dimensional vessel segment. The model involves WSS, lipid deposition and inflammatory response to reveal the dynamic balance existed between the lipid metabolism and the phagocytosis of macrophages.

RESULTS

The dynamic balance in microenvironment is influenced by both the WSS and the interactions with microenvironmental factors, and consequently results in the longitudinal heterogeneity observed in plaque pathology. In addition, plaque heterogeneity can be reduced by decreasing low WSS area at downstream, as well as by altering the phagocytic abilities of macrophage on lipoproteins, which may be used to develop future plaque regression strategies.

CONCLUSIONS

This multiscale modeling provides a framework to understand the mechanisms in dynamics of plaque composition and also provides quantitative information to better risk stratification of plaque vulnerability in future clinical practice.

Constructing Mal-Efferocytic Macrophage Model and Its Atherosclerotic Spheroids and Rat Model for Therapeutic Evaluation

Efferocytosis, responsible for apoptotic cell clearance, is an essential factor against atherosclerosis. It is reported that efferocytosis is severely impaired in fibroatheroma, especially in vulnerable thin cap fibroatheroma. However, there is a shortage of studies on efferocytosis defects in cell and animal models. Here, the impacts of oxidized low density lipoprotein (ox-LDL) and glut 1 inhibitor (STF31) on efferocytosis of macrophages are studied, and an evaluation system is constructed. Through regulating the cell ratios and stimulus, three types of atherosclerotic spheroids are fabricated, and a necrotic core emerges with surrounding apoptotic cells. Rat models present a similar phenomenon in that substantial apoptotic cells are uncleared in time in vulnerable plaque, and the model period is shortened to 7 weeks. Mechanism studies reveal that ox-LDL, through mRNA and miRNA modulation, downregulates efferocytosis receptor (PPARγ/LXRα/MerTK), internalization molecule (SLC29a1), and upregulates the competitive receptor CD300a that inhibits efferocytosis receptor-ligand binding process. The foam cell differentiation has also confirmed that CD36 and Lp-PLA2 levels are significantly elevated, and macrophages present an interesting transition into prothrombic phenotype. Collectively, the atherosclerotic models featured by efferocytosis defect provide a comprehensive platform to evaluate the efficacy of medicine and biomaterials for atherosclerosis treatment.

Targeting mitochondrial function in macrophages: A novel treatment strategy for atherosclerotic cardiovascular disease?

Atherosclerotic cardiovascular disease is a major cause of morbidity and mortality due to chronic arterial injury caused by hyperlipidemia, hypertension, inflammation and oxidative stress. Recent studies have shown that the progression of this disease is associated with mitochondrial dysfunction and with the accumulation of mitochondrial alterations within macrophages of atherosclerotic plaques. These alterations contribute to processes of inflammation and oxidative stress. Among the many players involved, macrophages play a pivotal role in atherogenesis as they can exert both beneficial and deleterious effects due to their anti- and pro-inflammatory properties. Their atheroprotective functions, such as cholesterol efflux and efferocytosis, as well as the maintenance of their polarization towards an anti-inflammatory state, are particularly dependent on mitochondrial metabolism. Moreover, in vitro studies have demonstrated deleterious effects of oxidized LDL on macrophage mitochondrial function, resulting in a switch to a pro-inflammatory state and to a potential loss of atheroprotective capacity. Therefore, preservation of mitochondrial function is now considered a legitimate therapeutic strategy. This review focuses on the potential therapeutic strategies that could improve the mitochondrial function of macrophages, enabling them to maintain their atheroprotective capacity. These emerging therapies could play a valuable role in counteracting the progression of atherosclerotic lesions and possibly inducing their regression.

Nonnegative matrix factorization analysis and multiple machine learning methods identified IL17C and ACOXL as novel diagnostic biomarkers for atherosclerosis

BACKGROUND

Atherosclerosis is the common pathological basis for many cardiovascular and cerebrovascular diseases. The purpose of this study is to identify the diagnostic biomarkers related to atherosclerosis through machine learning algorithm.

METHODS

Clinicopathological parameters and transcriptomics data were obtained from 4 datasets (GSE21545, GSE20129, GSE43292, GSE100927). A nonnegative matrix factorization algorithm was used to classify arteriosclerosis patients in GSE21545 dataset. Then, we identified prognosis-related differentially expressed genes (DEGs) between the subtypes. Multiple machine learning methods to detect pivotal markers. Discrimination, calibration and clinical usefulness of the predicting model were assessed using area under curve, calibration plot and decision curve analysis respectively. The expression level of the feature genes was validated in GSE20129, GSE43292, GSE100927.

RESULTS

2 molecular subtypes of atherosclerosis was identified, and 223 prognosis-related DEGs between the 2 subtypes were identified. These genes are not only related to epithelial cell proliferation, mitochondrial dysfunction, but also to immune related pathways. Least absolute shrinkage and selection operator, random forest, support vector machine- recursive feature elimination show that IL17C and ACOXL were identified as diagnostic markers of atherosclerosis. The prediction model displayed good discrimination and good calibration. Decision curve analysis showed that this model was clinically useful. Moreover, IL17C and ACOXL were verified in other 3 GEO datasets, and also have good predictive performance.

CONCLUSION

IL17C and ACOXL were diagnostic genes of atherosclerosis and associated with higher incidence of ischemic events.

Surface modification of biodegradable magnesium alloy with poly (L-lactic acid) and sulfonated hyaluronic acid nanoparticles for cardiovascular application

Magnesium (Mg) and its alloys have attracted extensive attention of researchers in the field of cardiovascular implants due to their good mechanical properties and biosafety. Constructing a multifunctional hybrid coating seems to be an effective strategy to address the insufficient endothelialization and poor corrosion resistance of Mg alloy vascular stents. In this study, a dense layer of magnesium fluoride (MgF₂) was prepared on the surface of Mg alloy aiming at better corrosion resistance; Thereafter, sulfonated hyaluronic acid (S-HA) was made into small sized nanoparticles (NP) which were deposited on the MgF₂ surface by self-assembly method, followed with poly-L-lactic acid (PLLA) coating preparation by one-step pulling method. The blood and cell tests showed that the composite coating had good blood compatibility, pro-endothelial, anti-hyperplasia and anti-inflammatory functions. Compared to current clinical PLLA@ Rapamycin coating, our PLLA/NP@S-HA coating showed better functions of promoting endothelial cells growth. These results strongly furnished a promising and feasible strategy for the surface modification of Mg-based degradable cardiovascular stents.

Lipid Droplet Protein PLIN1 Regulates Inflammatory Polarity in Human Macrophages and is Involved in Atherosclerotic Plaque Development by Promoting Stable Lipid Storage

AIM

Perilipins (PLINs), peripheral lipid droplet (LD) proteins, play important roles in lipid accumulation and maturation in adipocytes. The relationship between PLIN family proteins and macrophage polarization in atherosclerosis has not been elucidated.

METHODS

The experiments used tissues from human arteries of 65 patients who had undergone a carotid endarterectomy, and cultured macrophages generated from healthy human peripheral blood mononuclear cells.

RESULTS

Plaque immunohistochemistry demonstrated co-expression of PLIN1 and PLIN2 in both symptomatic (n=31) and asymptomatic patients (n=34). PLIN2 mRNA expression increased 3.38-fold in the symptomatic group compared with those from asymptomatic. PLIN1 was not expressed on small LDs at a shorter incubation but was on large LDs at longer incubation with oxidized LDL and VLDL, while PLIN2 was observed after 24 h and increased with a longer incubation in cultured M1 macrophage. In M2 macrophages, PLIN1 was seen as early as 24 h following incubation with VLDL, and LD size increased with longer incubation. PLIN1 overexpression increased the size of LDs in M1 macrophages, even after a short incubation, and reduced the RNA expression of TNFA, MMP2, ABCA1, and ABCG1 versus the M1 control. Conversely, silencing of PLIN1 in M2 macrophages had the opposite effects on LD size and RNA expression.

CONCLUSION

There was a relationship between macrophage polarity, cytosolic LD size, and PLIN1/PLIN2 expression levels. PLIN2 was mainly expressed in arterial plaques in symptomatic stroke patients, and associated with the inflammatory phenotype of human macrophages, while PLIN1 expression is closely associated with plaque stability and the anti-inflammatory phenotype.

Role of prostaglandin E2 in macrophage polarization: Insights into atherosclerosis

Atherosclerosis, a trigger of cardiovascular disease, poses grave threats to human health. Although atherosclerosis depends on lipid accumulation and vascular wall inflammation, abnormal phenotypic regulation of macrophages is considered the pathological basis of atherosclerosis. Macrophage polarization mainly refers to the transformation of macrophages into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes, which has recently become a much-discussed topic. Increasing evidence has shown that M2 macrophage polarization can alleviate atherosclerosis progression. PGE₂ is a bioactive lipid that has been observed to be elevated in atherosclerosis and to play a pro-inflammatory role, yet recent studies have reported that PGE₂ promotes anti-inflammatory M2 macrophage polarization and mitigates atherosclerosis progression. However, the mechanisms by which PGE₂ acts remain unclear. This review summarizes current knowledge of PGE₂ and macrophages in atherosclerosis. Additionally, we discuss potential PGE₂ mechanisms of macrophage polarization, including CREB, NF-κB, and STAT signaling pathways, which may provide important therapeutic strategies based on targeting PGE₂ pathways to modulate macrophage polarization for atherosclerosis treatment.

Tuning macrophages for atherosclerosis treatment

Atherosclerosis is a chronic inflammatory vascular disease and a leading cause of death worldwide. Macrophages play an important role in inflammatory responses, cell-cell communications, plaque growth and plaque rupture in atherosclerotic lesions. Here, we review the sources, functions and complex phenotypes of macrophages in the progression of atherosclerosis, and discuss the recent approaches in modulating macrophage phenotype and autophagy for atherosclerosis treatment. We then focus on the drug delivery strategies that target macrophages or use macrophage membrane-coated particles to deliver therapeutics to the lesion sites. These biomaterial-based approaches that target, modulate or engineer macrophages have broad applications for disease therapies and tissue regeneration.

Opuntia dillenii Haw. Polysaccharide Promotes Cholesterol Efflux in THP-1-Derived Foam Cells via the PPARγ-LXRα Signaling Pathway

There is increasing evidence supporting a role for enhanced macrophage cholesterol efflux in ameliorating atherosclerosis. Opuntia dillenii Haw. polysaccharide (ODP-Ia), the most important functional component obtained from Opuntia dillenii Haw. stem, has anti-atherosclerosis effects. Therefore, we propose that ODP-Ia could promote cholesterol efflux via the PPARγ-LXRα signaling pathway. In this study, THP-1 foam cells derived from macrophages were treated with different concentrations of ODP-Ia, GGPP (antagonist of LXRα) and GW9662 (antagonist of PPARγ), with or without 15 nmol ODP-Ia. The total cholesterol content in the cells was measured. The mRNA of ABCA1, ABCG1, PPARγ, LXRα and their protein levels in the foam cells were detected by RT−PCR and Western blot, respectively. The results showed that ODP-Ia plays a role in significantly promoting cholesterol efflux (p < 0.05) by upregulating the expression of ABCA1, ABCG1, SR-BI, PPARγ, PPARα and LXRα. Meanwhile, PPARγ and LXRα antagonists dramatically interfered the cholesterol efflux mediated by ODP-Ia (p < 0.05) and dramatically inhibited the upregulating effect of ODP-Ia on the expression of PPARγ, LXRα, ABCA1 and ABCG1 at both protein and mRNA levels (p < 0.05). In conclusion, ODP-Ia promotes cholesterol efflux in the foam cells through activating the PPARγ-LXRα signaling pathway. This bioactivity suggested that ODP-Ia may be of benefit in treating atherosclerosis.

Functions and therapeutic interventions of non-coding RNAs associated with TLR signaling pathway in atherosclerosis

Nowadays, emerging data demonstrate that the toll-like receptor (TLR) signaling pathway plays an important role in the progression of inflammatory atherosclerosis. Indeed, dysregulated TLR signaling pathway could be a cornerstone of inflammation and atherosclerosis, which contributes to the development of cardiovascular diseases. It is interesting to note that this pathway is heavily controlled by several mechanisms, such as epigenetic factors in which the role of non-coding RNAs (ncRNAs), particularly microRNAs and long noncoding RNAs as well as circular RNAs in the pathogenesis of atherosclerosis has been well studied. Recent years have seen a significant surge in the amount of research exploring the interplay between ncRNAs and TLR signaling pathway downstream targets in the development of atherosclerosis; however, there is still considerable room for improvement in this field. The current study was designed to review underlying mechanisms of TLR signaling pathway and ncRNA interactions to shed light on therapeutic implications in patients with atherosclerosis.

The intracellular signaling pathways governing macrophage activation and function in human atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by lipid accumulation and plaque formation in arterial vessel walls. Atherosclerotic plaques narrow the arterial lumen to increase the risk of heart attacks, ischemic stroke and peripheral vascular disease, which are major and worldwide health and economic burdens. Macrophage accumulation within plaques is characteristic of all stages of atherosclerosis and their presence is a potential marker of disease activity and plaque stability. Macrophages engulf lipids and modified lipoproteins to form foam cells that express pro-inflammatory and chemotactic effector molecules, stress inducing factors and reactive oxygen species. They control plaque stability and rupture through secretion of metalloproteinases and extracellular matrix degradation. Although macrophages can worsen disease by propagating inflammation, they can stabilize atherosclerotic plaques through tissue remodeling, promoting the formation of a fibrous cap, clearing apoptotic cells to prevent necrotic core formation and through vascular repair. In atherosclerosis, macrophages respond to dyslipidaemia, cytokines, dying cells, metabolic factors, lipids, physical stimuli and epigenetic factors and exhibit heterogeneity in their activation depending on the stimuli they receive. Understanding these signals and the pathways driving macrophage function within developing and established plaques and how they can be pharmacologically modulated, represents a strategy for the prevention and treatment of atherosclerosis. This review focusses on the current understanding of factors controlling macrophage heterogeneity and function in atherosclerosis. Particular attention is given to the macrophage intracellular signaling pathways and transcription factors activated by biochemical and biophysical stimuli within plaques, and how they are integrated to regulate plaque formation and stability.

Macrophage-, Dendritic-, Smooth Muscle-, Endothelium-, and Stem Cells-Derived Foam Cells in Atherosclerosis

Atherosclerosis is an inflammatory disease depending on the buildup, called plaque, of lipoproteins, cholesterol, extracellular matrix elements, and various types of immune and non-immune cells on the artery walls. Plaque development and growth lead to the narrowing of the blood vessel lumen, blocking blood flow, and eventually may lead to plaque burst and a blood clot. The prominent cellular components of atherosclerotic plaque are the foam cells, which, by trying to remove lipoprotein and cholesterol surplus, also participate in plaque development and rupture. Although the common knowledge is that the foam cells derive from macrophages, studies of the last decade clearly showed that macrophages are not the only cells able to form foam cells in atherosclerotic plaque. These findings give a new perspective on atherosclerotic plaque formation and composition and define new targets for anti-foam cell therapies for atherosclerosis prevention. This review gives a concise description of foam cells of different pedigrees and describes the main mechanisms participating in their formation and function.

Exosome-Loaded Pro-efferocytic Vascular Stent with Lp-PLA2-Triggered Release for Preventing In-Stent Restenosis

The efferocytosis defect is regarded as a pivotal event of atherosclerosis. The failure to clear apoptotic cells in atherosclerotic plaques under vascular stents causes a failure to resolve the inflammation underneath. However, efferocytosis repair is still confined to nonstenting therapeutics. Here, we identified a pro-efferocytotic agent and accordingly developed a bioresponsive pro-efferocytotic vascular stent aimed for poststenting healing. Exosomes derived from mesenchymal stem cells were found to be able to regulate efferocytosis via SLC2a1, STAT3/RAC1, and CD300a pathways and modulate foam cell formation processes through a CD36-mediated pathway. Pro-efferocytotic exosomes were encapsulated into liposome-based multivesicular chambers and grafted onto vascular stents. The multivesicular vesicles were able to release exosomes under the Lp-PLA₂ environment. Compared to bare metal stents, exosome-stents in the presence of Lp-PLA₂ enhanced the ratio of apoptotic cell clearance and reduced the neointimal thickness in the mal-efferocytotic rat model. Overall, we identified a pro-efferocytic agent─exosomes that are able to regulate target cells via multiple signaling pathways and are good candidates to serve complex pathological environments, and this bioresponsive pro-efferocytotic vascular stent is an attractive approach for prevention of poststenting complications.

Synergistic Hypolipidemic Effects and Mechanisms of Phytochemicals: A Review

Hyperlipidemia, a chronic disorder of abnormal lipid metabolism, can induce obesity, diabetes, and cardiovascular and cerebrovascular diseases such as coronary heart disease, atherosclerosis, and hypertension. Increasing evidence indicates that phytochemicals may serve as a promising strategy for the prevention and management of hyperlipidemia and its complications. At the same time, the concept of synergistic hypolipidemic and its application in the food industry is rapidly increasing as a practical approach to preserve and improve the health-promoting effects of functional ingredients. The current review focuses on the effects of single phytochemicals on hyperlipidemia and its mechanisms. Due to the complexity of the lipid metabolism regulatory network, the synergistic regulation of different metabolic pathways or targets may be more effective than single pathways or targets in the treatment of hyperlipidemia. This review summarizes for the first time the synergistic hypolipidemic effects of different combinations of phytochemicals such as combinations of the same category of phytochemicals and combinations of different categories of phytochemicals. In addition, based on the different metabolic pathways or targets involved in synergistic effects, the possible mechanisms of synergistic hypolipidemic effects of the phytochemical combination are illustrated in this review. Hence, this review provides clues to boost more phytochemical synergistic hypolipidemic research and provides a theoretical basis for the development of phytochemicals with synergistic effects on hyperlipidemia and its complications.

Mechanoimmunology: Are inflammatory epigenetic states of macrophages tuned by biophysical factors?

Many inflammatory diseases that are responsible for a majority of deaths are still uncurable, in part as the underpinning pathomechanisms and how to combat them is still poorly understood. Tissue-resident macrophages play pivotal roles in the maintenance of tissue homeostasis, but if they gradually convert to proinflammatory phenotypes, or if blood-born proinflammatory macrophages persist long-term after activation, they contribute to chronic inflammation and fibrosis. While biochemical factors and how they regulate the inflammatory transcriptional response of macrophages have been at the forefront of research to identify targets for therapeutic interventions, evidence is increasing that physical factors also tune the macrophage phenotype. Recently, several mechanisms have emerged as to how physical factors impact the mechanobiology of macrophages, from the nuclear translocation of transcription factors to epigenetic modifications, perhaps even DNA methylation. Insight into the mechanobiology of macrophages and associated epigenetic modifications will deliver novel therapeutic options going forward, particularly in the context of increased inflammation with advancing age and age-related diseases. We review here how biophysical factors can co-regulate pro-inflammatory gene expression and epigenetic modifications and identify knowledge gaps that require urgent attention if this therapeutic potential is to be realized.

ROS responsive nanoparticles loaded with lipid-specific AIEgen for atherosclerosis-targeted diagnosis and bifunctional therapy

Atherosclerosis, which is triggered by endothelial damage, progressive local inflammation and excessive lipid accumulation, is one of the most common cardiovascular diseases in recent years. Drug delivery systems have shown great potential for the accurate diagnosis and effective treatment of early atherosclerosis, but are accompanied by disadvantages such as poor stability, lack of active targeting and non-specific recognition capabilities, which still need to be further developed. In our work, a multifunctional nanoparticle (LFP/PCDPD) with reactive oxygen species (ROS) responsive drug release, lipid removal, and lipid-specific AIE fluorescence imaging was constructed. Cyclodextrin structure with lipid removal function and PMEMA blocks with ROS-response-mediated hydrophobic to hydrophilic conversion were simultaneously introduced into the structure of LFP/PCDPD to load the anti-inflammatory drug prednisolone (Pred) and lipid-specific AIEgen (LFP). The active targeting function of LFP/PCDPD was conferred by the high affinity of dextran to the vascular adhesion molecule-1 (VCAM-1) and CD44 receptor on the surface of broken endothelial cells. After intravenous injection into ApoE^-/- mice, LFP/PCDPD actively enriched in the microenvironment of local ROS overexpression and rich lipids in atherosclerosis. Pred and LFP were released while lipids were removed, thus enabling proactive targeting of atherosclerosis and efficient "two-pronged" treatment.

Understanding the role of alternative macrophage phenotypes in human atherosclerosis

INTRODUCTION

Atherosclerosis-based ischemic heart disease is still the primary cause of death throughout the world. Over the past decades there has been no significant changes in the therapeutic approaches to atherosclerosis, which are mainly based on lipid lowering therapies and management of comorbid conditions such as diabetes and hypertension. The involvement of macrophages in atherosclerosis has been recognized for decades. More recently, a more detailed and sophisticated understanding of their various phenotypes and roles in the atherosclerotic process has been recognized. This new data is revealing how specific subtypes of macrophage-induced inflammation may have distinct effects on atherosclerosis progression and may provide new approaches for treatment, based upon targeting of specific macrophage subtypes.

AREAS COVERED

We will comprehensively review the spectrum of macrophage phenotypes and how they contribute to atherosclerotic plaque development and progression.

EXPERT OPINION

Various signals derived from atherosclerotic lesions drive macrophages into complex subsets with different gene expression profiles, phenotypes, and functions, not all of which are understood. Macrophage phenotypes include those that enhance, heal, and regress the atherosclerotic lesions though various mechanisms. Targeting of specific macrophage phenotypes may provide a promising and novel approach to prevent atherosclerosis progression.

New insights into macrophage subsets in atherosclerosis

Macrophages in atherosclerotic patients are notably plastic and heterogeneous. Single-cell RNA sequencing (Sc RNA-seq) can provide information about all the RNAs in individual cells, and it is used to identify cell subpopulations in atherosclerosis (AS) and reveal the heterogeneity of these cells. Recently, some findings from Sc RNA-seq experiments have suggested the existence of multiple macrophage subsets in atherosclerotic plaque lesions, and these subsets exhibit significant differences in their gene expression levels and functions. These cells affect various aspects of plaque lesion development, stabilization, and regression, as well as plaque rupture. This article aims to review the content and results of current studies that used RNA-seq to explore the different types of macrophages in AS and the related molecular mechanisms as well as to identify the potential roles of these macrophage types in the pathogenesis of atherosclerotic plaques. Also, this review listed some new therapeutic targets for delaying atherosclerotic lesion progression and treatment based on the experimental results.

Regulation of microglia phagocytosis and potential involvement of exercise

Microglia are considered the main phagocytic cells in the central nervous system, remodeling neural circuits by pruning synapses during development. Microglial phagocytosis is also a crucial process in maintaining adult brain homeostasis and clearing potential toxic factors, which are recognized to be associated with neurodegenerative and neuroinflammatory disorders. For example, microglia can engulf amyloid-β plaques, myelin debris, apoptotic cells, and extracellular harmful substances by expressing a variety of specific receptors on the cell surface or by reprogramming intracellular glucose and lipid metabolism processes. Furthermore, physical exercise has been implicated to be one of the non-pharmaceutical treatments for various nervous system diseases, which is closely related to neuroplasticity and microglia functions including proliferation, activation, and phagocytosis. This review focuses on the central regulatory mechanisms related to microglia phagocytosis and the potential role of exercise training in this process.

The Long Non-coding RNA AC148477.2 Is a Novel Therapeutic Target Associated With Vascular Smooth Muscle Cells Proliferation of Femoral Atherosclerosis

Arteriosclerosis obliterans (ASO) is a limb manifestation of large vessel atherosclerosis. Phenotype switching of vascular smooth muscle cells (VSMCs) occurs in the course of the pathological process. The underlying mechanism of SMCs proliferation remains unclear. Several studies have demonstrated that the dysregulation of long non-coding RNA (lncRNAs) plays a pivotal part in the progression of ASO by exacerbating the proliferation of VSMCs. Based on the endogenous competitive RNA (ceRNA) hypothesis, the mechanism of lncRNAs involved in the pathology of VSMCs was exposed, while the entire map of the regulatory network remains to be elucidated. In the current study, genes and the lncRNAs modules that are relevant to the clinical trait were confirmed through weighted gene co-expression network analysis (WGCNA). In this study, we comprehensively constructed a specific lncRNAs-mediated ceRNA and RBP network. The three lncRNAs, HMGA1P4, C5orf66, and AC148477.2, influenced the proliferation of VSMCs and were found to be associated with the immune landscape, thus they were ultimately screened out. Further verification revealed that AC147488.2 was significantly down-regulated in both ASO arteries and all stages of proliferative VSMCs, which implied that AC147488.2 might have a significant impact on ASO. This finding would improve our understanding of the epigenetic regulation of ASO and unravel novel diagnostic and therapeutic targets.

Identification and Validation of Candidate Gene Module Along With Immune Cells Infiltration Patterns in Atherosclerosis Progression to Plaque Rupture via Transcriptome Analysis

Objective

To explore the differentially expressed genes (DEGs) along with infiltrating immune cells landscape and their potential mechanisms in the progression of atherosclerosis from onset to plaque rupture.

Methods

In this study, three atherosclerosis-related microarray datasets were downloaded from the NCBI-GEO database. The gene set enrichment analysis (GSEA) was performed for interpreting the biological insights of gene expression data. The CIBERSORTx algorithm was applied to infer the relative proportions of infiltrating immune cells of the atherosclerotic samples. DEGs of the datasets were screened using R. The protein interaction network was constructed via STRING. The cluster genes were analyzed by the Cytoscape software. Gene ontology (GO) enrichment was performed via geneontology.org. The least absolute shrinkage and selection operator (LASSO) logistic regression algorithm and receiver operating characteristics (ROC) analyses were performed to build machine learning models for differentiating atherosclerosis status. The Pearson correlation analysis was carried out to illustrate the relationship between cluster genes and immune cells. The expression levels of the cluster genes were validated in two external cohorts. Transcriptional factors and drug-gene interaction analysis were performed to investigate the promising targets for atherosclerosis intervention.

Results

Pathways related to immunoinflammatory responses were identified according to GSEA analysis, and the detailed fractions infiltrating immune cells were compared between the early and advanced atherosclerosis. Additionally, we identified 170 DEGs in atherosclerosis progression (|log2FC|≥1 and adjusted p < 0.05). They were mainly enriched in GO terms relating to inflammatory response and innate immune response. A cluster of nine genes, such as ITGB2, C1QC, LY86, CTSS, C1QA, CSF1R, LAPTM5, VSIG4, and CD163, were found to be significant, and their correlations with infiltrating immune cells were calculated. The cluster genes were also validated to be upregulated in two external cohorts. Moreover, C1QA and ITGB2 may exert pathogenic functions in the entire process of atherogenesis.

Conclusions

We reanalyzed the transcriptomic signature of atherosclerosis development from onset to plaque rupture along with the landscape of the immune cell, as well as revealed new insights and specific prospective DEGs for the investigation of disease-associated dynamic molecular processes and their regulations with immune cells.

A Bibliometric and Knowledge-Map Analysis of Macrophage Polarization in Atherosclerosis From 2001 to 2021

In recent years, studies of macrophage polarization in atherosclerosis have become an intense area of research. However, there are few bibliometric analyses regarding this area. In this review, we used CiteSpace 5.8.R3 and VOSviewer 1.6.16 software to perform text mining and knowledge-map analysis. We explored the development process, knowledge structure, research hotspots, and potential trends using a bibliometric and knowledge-map analysis to provide researchers with a macroscopic view of this field. The studies concerning macrophage polarization in atherosclerosis were downloaded from the Web of Science Core Collection. A total of 781 studies were identified and published by 954 institutions from 51 countries/regions. The number of studies of macrophage polarization in atherosclerosis increased over time. Arteriosclerosis Thrombosis and Vascular Biology published the highest number of articles and was the top co-cited journal. De Winther was the most prolific researcher, and Moore had the most co-citations. The author co-occurrence map illustrated that there was active cooperation among researchers. The most productive countries were the United States and China. Amsterdam University, Harvard University, and Maastricht University were the top three productive institutions in the research field. Keyword Co-occurrence, Clusters, and Burst analysis showed that “inflammation,” “monocyte,” “NF kappa B,” “mechanism,” and “foam cell” appeared with the highest frequency in studies. “Oxidative stress,” “coronary heart disease,” and “prevention” were the strongest citation burst keywords from 2019 to 2021.

Cholesterol accumulation induced by acetylated LDL exposure modifies the enzymatic activities of the TCA cycle without impairing the respiratory chain functionality in macrophages

The unregulated uptake of modified low-density lipoproteins (LDL) by macrophages leads to foam cell formation, promoting atherosclerotic plaque progression. The cholesterol efflux capacity of macrophages by the ATP-Binding Cassette transporters depends on the ATP mitochondrial production. Therefore, the mitochondrial function maintenance is crucial in limiting foam cell formation. Thus, we aimed to investigate the mechanisms involved in the mitochondrial dysfunction that may occur in cholesterol-laden macrophages. We incubated THP-1 macrophages with acetylated LDL (acLDL) to obtain cholesterol-laden cells or with mildly oxidized LDL (oxLDL) to generate cholesterol- and oxidized lipids-laden cells. Cellular cholesterol content was measured in each condition. Mitochondrial function was evaluated by measurement of several markers of energetic metabolism, oxidative phosphorylation, oxidative stress, mitochondrial biogenesis and dynamics. OxLDL-exposed macrophages exhibited a significantly reduced mitochondrial respiration and complexes I and III activities, associated to an oxidative stress state and a reduced mitochondrial DNA copy number. Meanwhile, acLDL-exposed macrophages featured an efficient oxidative phosphorylation despite the decreased activities of aconitase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. Our study revealed that mitochondrial function was differently impacted according to the nature of modified LDL. Exposure to cholesterol and oxidized lipids carried by oxLDL leads to a mitochondrial dysfunction in macrophages, affecting the mitochondrial respiratory chain functional capacity, whereas the cellular cholesterol enrichment induced by acLDL exposure results in a tricarboxylic acid cycle shunt while maintaining mitochondrial energetic production, reflecting a metabolic adaptation to cholesterol intake. These new mechanistic insights are of direct relevance to the understanding of the mitochondrial dysfunction in foam cells.

Molecular Pharmacology of Inflammation Resolution in Atherosclerosis

Atherosclerosis is one of the most important problems of modern medicine as it is the leading cause of hospitalizations, disability, and mortality. The key role in the development and progression of atherosclerosis is the imbalance between the activation of inflammation in the vascular wall and the mechanisms of its control. The resolution of inflammation is the most important physiological mechanism that is impaired in atherosclerosis. The resolution of inflammation has complex, not fully known mechanisms, in which lipid mediators derived from polyunsaturated fatty acids (PUFAs) play an important role. Specialized pro-resolving mediators (SPMs) represent a group of substances that carry out inflammation resolution and may play an important role in the pathogenesis of atherosclerosis. SPMs include lipoxins, resolvins, maresins, and protectins, which are formed from PUFAs and regulate many processes related to the active resolution of inflammation. Given the physiological importance of these substances, studies examining the possibility of pharmacological effects on inflammation resolution are of interest.

The Immunomodulatory Effects of Statins on Macrophages

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors used worldwide to manage dyslipidaemia and thus limit the development of atherosclerotic disease and its complications. These atheroprotective drugs are now known to exert pleiotropic actions outside of their cholesterol-lowering activity, including altering immune cell function. Macrophages are phagocytic leukocytes that play critical functional roles in the pathogenesis of atherosclerosis and are directly targeted by statins. Early studies documented the anti-inflammatory effects of statins on macrophages, but emerging evidence suggests that these drugs can also enhance pro-inflammatory macrophage responses, creating an unresolved paradox. This review comprehensively examines the in vitro, in vivo, and clinical literature to document the statin-induced changes in macrophage polarization and immunomodulatory functions, explore the underlying mechanisms involved, and offer potential explanations for this paradox. A better understanding of the immunomodulatory actions of statins on macrophages should pave the way for the development of novel therapeutic approaches to manage atherosclerosis and other chronic diseases and conditions characterised by unresolved inflammation.

Cadherin-11 Regulates Macrophage Development and Function

Cadherin-11 (CDH11) is a cell-cell adhesion protein that has previously been reported to play an important role in the pathogenesis of pulmonary fibrosis. It is expressed on macrophages in the fibrotic lung. However, the role of CDH11 on macrophage biology has not yet been studied. We show using immunophenotypic analyses that Cdh11^-/- mice have fewer recruited monocyte-derived macrophages and Ly6C^hi monocytes in the lungs compared to wild-type mice in the intraperitoneal bleomycin-induced pulmonary fibrosis model. Additionally, fewer Ly6C^hi monocytes were detected in the bone marrow and peripheral blood of naive Cdh11^-/- mice. Given that macrophages are derived from monocytes, we investigated the precursors of the monocyte/macrophage lineage in the bone marrow. We found increased numbers of CMPs and reduced numbers of GMPs and MPs/cMoPs in Cdh11^-/- mice compared to wild-type mice, suggesting decreased differentiation towards the myeloid lineage in Cdh11^-/- mice. Furthermore, we show using bone marrow cells that loss of CDH11 impaired monocyte to macrophage differentiation. We also demonstrate that CDH11 deficiency repressed the M2 program and impaired the phagocytic function of bone marrow-derived macrophages. Overall, our findings demonstrate a role for CDH11 in macrophage development, M2 polarization, and phagocytic function.

Engineering nanobodies for next-generation molecular imaging

In recent years, nanobodies have emerged as ideal imaging agents for molecular imaging. Molecular nanobody imaging combines the specificity of nanobodies with the sensitivity of state-of-the-art molecular imaging modalities, such as positron emission tomography (PET). Given that modifications of nanobodies alter their pharmacokinetics (PK), the engineering strategies that combine nanobodies with radionuclides determine the effectiveness, reliability, and safety of the molecular imaging probes. In this review, we introduce conjugation strategies that have been applied to nanobodies, including random conjugation, ^99mTc tricarbonyl chemistry, sortase A-mediated site-specific conjugation, maleimide-cysteine chemistry, and click chemistries. We also summarize the latest advances in nanobody tracers, emphasizing their preclinical and clinical use. In addition, we elaborate on nanobody-based near-infrared fluorescence (NIRF) imaging and image-guided surgery.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

miRNA-29a inhibits atherosclerotic plaque formation by mediating macrophage autophagy via PI3K/AKT/mTOR pathway

Background: miR-29a plays a vital role in AS, but the relationship between the miR-29a-targeted PI3K signaling pathway and AS remains unclear. Therefore, this study was carried out.

Methods: Gene expression profiles from the GEO database containing AS samples were analyzed. ApoE^−/− mice and RAW264.7 cells were treated with miR-29a negative control (NC), miR-29a mimic and miR-29a inhibitor to establish the AS model. Then MOVAT staining, TEM, Western blotting, and immunofluorescence staining were adopted for testing target proteins.

Results: DEGs were identified from GSE137578, GSE132651, GSE113969, GSE43292, and GSE97210 datasets. It was found that there were targeted binding sites between miR-29a and PIK3CA. Besides, GO and KEGG analysis demonstrated that autophagy was an enriched pathway in AS. Later, PPI network was depicted, and hub genes were then determined. The results revealed that miR-29a suppressed the areas of plaques and lesional macrophages, but had no impact on VSMCs. TEM results showed the organelles pyknosis of lesional macrophages damaged morphological changes. Furthermore, miR-29a amplified the M2-like macrophages but suppressed the polarization of M1-like macrophages in atherosclerotic plaques. According to mouse and RAW 264.7 cell experiments, miR-29a significantly inhibited the protein expressions of PI3K, p-PI3K, p-AKT, and p-mTOR, which were consistent with the increased expressions of autophagy-related proteins, Beclin 1 and LC3II. However, the miR-29a suppression exhibited the contrary results.

Conclusion: MiR-29a elevation induces the increase of autophagy by down-regulating the PI3K/AKT/mTOR pathway in the progression of AS, indicating that miR-29a is a novel therapeutic strategy for AS.

Stroke induces disease-specific myeloid cells in the brain parenchyma and pia

Inflammation triggers secondary brain damage after stroke. The meninges and other CNS border compartments serve as invasion sites for leukocyte influx into the brain thus promoting tissue damage after stroke. However, the post-ischemic immune response of border compartments compared to brain parenchyma remains poorly characterized. Here, we deeply characterize tissue-resident leukocytes in meninges and brain parenchyma and discover that leukocytes respond differently to stroke depending on their site of residence. We thereby discover a unique phenotype of myeloid cells exclusive to the brain after stroke. These stroke-associated myeloid cells partially resemble neurodegenerative disease-associated microglia. They are mainly of resident microglial origin, partially conserved in humans and exhibit a lipid-phagocytosing phenotype. Blocking markers specific for these cells partially ameliorates stroke outcome thus providing a potential therapeutic target. The injury-response of myeloid cells in the CNS is thus compartmentalized, adjusted to the type of injury and may represent a therapeutic target.

Functional Phenotypes of Intraplaque Macrophages and Their Distinct Roles in Atherosclerosis Development and Atheroinflammation

Macrophages are the key inflammatory cell type involved in all stages of atherosclerosis development and progression, as demonstrated by numerous studies. Correspondingly, macrophages are currently regarded as a promising therapeutic target for the development of new treatment approaches. The macrophage population is heterogeneous and dynamic, as these cells can switch between a number of distinct functional states with pro- and anti-atherogenic activity in response to various stimuli. An atherosclerotic plaque microenvironment defined by cytokine levels, cell-to-cell interactions, lipid accumulation, hypoxia, neoangiogenesis, and intraplaque haemorrhage may guide local macrophage polarization processes within the lesion. In this review, we discuss known functional phenotypes of intraplaque macrophages and their distinct contribution to ahteroinflammation.

Lipid Droplet Accumulation Promotes RPE Dysfunction

Non-exudative age-related macular degeneration (AMD) is an irreversibly progressive retinal degenerative disease characterized by dysfunction and loss of retinal pigment epithelium (RPE). It has been suggested that impaired phagocytosis of the RPE is involved in the progression of non-exudative AMD, but the mechanism is not fully clear. In this study, we investigated the effect of lipid droplet accumulation on RPE function. Compared to young mice, the expression of lipid droplet-associated proteins increased in the RPE-choroidal complex, and lipid droplet in the RPE was observed in aged pigmented mice (12-month-old). Repeated treatment of the photoreceptor outer segment against ARPE-19 resulted in lipid droplets in ARPE-19 cells in vitro. Oleic acid treatment for ARPE-19 cells to form intracellular lipid droplet reduced the POS uptake into the ARPE-19 cells without causing a decrease in cell viability. The suppression of the POS uptake by lipid droplet formation improved by inhibiting lipid droplet formation using triacsin C. Moreover, the amount of intracellular reactive oxygen species was suppressed by the triacsin C treatment. These results indicate that lipid droplet is involved in the RPE dysfunction, and inhibiting lipid droplet formation may be a target for preventing and treating non-exudative AMD.

Macrophage-targeted nanomedicine for the diagnosis and treatment of atherosclerosis

Nanotechnology could improve our understanding of the pathophysiology of atherosclerosis and contribute to the development of novel diagnostic and therapeutic strategies to further reduce the risk of cardiovascular disease. Macrophages have key roles in atherosclerosis progression and, therefore, macrophage-associated pathological processes are important targets for both diagnostic imaging and novel therapies for atherosclerosis. In this Review, we highlight efforts in the past two decades to develop imaging techniques and to therapeutically manipulate macrophages in atherosclerotic plaques with the use of rationally designed nanoparticles. We review the latest progress in nanoparticle-based imaging modalities that can specifically target macrophages. Using novel molecular imaging technology, these modalities enable the identification of advanced atherosclerotic plaques and the assessment of the therapeutic efficacy of medical interventions. Additionally, we provide novel perspectives on how macrophage-targeting nanoparticles can deliver a broad range of therapeutic payloads to atherosclerotic lesions. These nanoparticles can suppress pro-atherogenic macrophage processes, leading to improved resolution of inflammation and stabilization of plaques. Finally, we propose future opportunities for novel diagnostic and therapeutic strategies and provide solutions to challenges in this area for the purpose of accelerating the clinical translation of nanomedicine for the treatment of atherosclerotic vascular disease.

Inflammation, Oxidative Stress, Senescence in Atherosclerosis: Thioredoxine-1 as an Emerging Therapeutic Target

Atherosclerosis is a leading cause of cardiovascular diseases (CVD) worldwide and intimately linked to aging. This pathology is characterized by chronic inflammation, oxidative stress, gradual accumulation of low-density lipoproteins (LDL) particles and fibrous elements in focal areas of large and medium arteries. These fibrofatty lesions in the artery wall become progressively unstable and thrombogenic leading to heart attack, stroke or other severe heart ischemic syndromes. Elevated blood levels of LDL are major triggering events for atherosclerosis. A cascade of molecular and cellular events results in the atherosclerotic plaque formation, evolution, and rupture. Moreover, the senescence of multiple cell types present in the vasculature were reported to contribute to atherosclerotic plaque progression and destabilization. Classical therapeutic interventions consist of lipid-lowering drugs, anti-inflammatory and life style dispositions. Moreover, targeting oxidative stress by developing innovative antioxidant agents or boosting antioxidant systems is also a well-established strategy. Accumulation of senescent cells (SC) is also another important feature of atherosclerosis and was detected in various models. Hence, targeting SCs appears as an emerging therapeutic option, since senolytic agents favorably disturb atherosclerotic plaques. In this review, we propose a survey of the impact of inflammation, oxidative stress, and senescence in atherosclerosis; and the emerging therapeutic options, including thioredoxin-based approaches such as anti-oxidant, anti-inflammatory, and anti-atherogenic strategy with promising potential of senomodulation.