Monocyte Chemoattractant Protein-1, Inflammatory Biomarkers, and Prognosis of Patients With Ischemic Stroke or Transient Ischemic Attack: Fndings From a Nationwide Registry Study

BACKGROUND

Recent Mendelian randomization and meta-analysis highlight the relevance of MCP-1 (monocyte chemoattractant protein-1) in stroke. We aimed to investigate the associations between MCP-1 and clinical outcomes in patients with ischemic stroke or transient ischemic attack and test whether inflammation mediates or jointly contributes to the relationships.

METHODS AND RESULTS

A total of 10 700 patients from the Third China National Stroke Registry study were included. Multivariable Cox regression was used for recurrent stroke and all-cause death, and logistic regression was used for poor functional outcome. Mediation analyses were performed to clarify whether inflammation mediates the associations. After adjusting for potential confounders, low MCP-1 level (<337.6 pg/mL) was associated with a reduced risk of all-cause death (hazard ratio [HR], 0.65 [95% CI, 0.51-0.82]) and poor functional outcome (odds ratio, 0.81 [95% CI, 0.70-0.94]) but was not associated with recurrent stroke (HR, 1.10 [95% CI, 0.95-1.27]), compared with high MCP-1 level (≥337.6 pg/mL). The association between MCP-1 and all-cause death was partially mediated by highly sensitive C-reactive protein, interleukin-6, and YKL-40 (Chitinase-3-like protein 1; mediated proportion: 7.4%, 10.5%, and 7.4%, respectively). The corresponding mediated proportion for poor functional outcome was 9.9%, 17.1%, and 7.1%, respectively. Patients with combined high levels of MCP-1 and inflammatory biomarkers had the highest risks of all-cause death and poor functional outcome.

CONCLUSIONS

Low plasma MCP-1 level was associated with decreased risks of all-cause mortality and poor functional outcome after ischemic stroke or transient ischemic attack. Inflammation partially mediated and jointly contributed to the associations.

Elucidating the role of chemokines in inflammaging associated atherosclerotic cardiovascular diseases

Age-related inflammation or inflammaging is a critical deciding factor of physiological homeostasis during aging. Cardiovascular diseases (CVDs) are exquisitely associated with aging and inflammation and are one of the leading causes of high mortality in the elderly population. Inflammaging comprises dysregulation of crosstalk between the vascular and cardiac tissues that deteriorates the vasculature network leading to development of atherosclerosis and atherosclerotic-associated CVDs in elderly populations. Leukocyte differentiation, migration and recruitment holds a crucial position in both inflammaging and atherosclerotic CVDs through relaying the activity of an intricate network of inflammation-associated protein-protein interactions. Among these interactions, small immunoproteins such as chemokines play a major role in the progression of inflammaging and atherosclerosis. Chemokines are actively involved in lymphocyte migration and severe inflammatory response at the site of injury. They relay their functions via chemokine-G protein-coupled receptors-glycosaminoglycan signaling axis and is a principal part for the detection of age-related atherosclerosis and related CVDs. This review focuses on highlighting the detailed intricacies of the effects of chemokine-receptor interaction and chemokine oligomerization on lymphocyte recruitment and its evident role in clinical manifestations of atherosclerosis and related CVDs. Further, the role of chemokine mediated signaling for formulating next-generation therapeutics against atherosclerosis has also been discussed.

The role of CCL2/CCR2 axis in cancer and inflammation: The next frontier in nanomedicine

The communication between cells and their microenvironment represents an intrinsic and essential attribute that takes place in several biological processes, including tissue homeostasis and tissue repair. Among these interactions, inflammation is certainly a central biological response that occurs through cytokines and the crosstalk with their respective receptors. In particular, the interaction between CCL2 and its main receptor, CCR2, plays a pivotal role in both harmful and protective inflammatory states, including cancer-mediated inflammation. The activation of the CCL2/CCR2 axis was shown to dictate the migration of macrophages with immune-suppressive phenotype and to aggravate the progression of different cancer types. In addition, this interaction mediates metastasis formation, further limiting the potential therapeutic outcome of anti-cancer drugs. Attempts to inhibit pharmacologically the CCL2/CCR2 axis have yet to show its anti-cancer efficacy as a single agent, but it sheds light on its role as a powerful tool to selectively alleviate pro-tumorigenic and anti-repair inflammation. In this review, we will elucidate the role of CCL2/CCR2 axis in promoting cancer inflammation by activating the host pro-tumorigenic phenotype. Moreover, we will provide some insight into the potential therapeutic benefit of targeting the CCL2/CCR2 axis for cancer and inflammation using novel delivery systems, aiming to sensitize non-responders to currently approved immunotherapies and offer new combinatory approaches.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

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

CCL2 is a key regulator and therapeutic target for periodontitis

AIM

Our previous study revealed that the C-C motif chemokine receptor 2 (CCR2) is a promising target for periodontitis prevention and treatment. However, CCR2 is a receptor with multiple C-C motif chemokine ligands (CCLs), including CCL2, CCL7, CCL8, CCL13 and CCL16, and which of these ligands plays a key role in periodontitis remains unclear. The aim of the present study was to explore the key functional ligand of CCR2 in periodontitis and to evaluate the potential of the functional ligand as a therapeutic target for periodontitis.

MATERIALS AND METHODS

The expression levels and clinical relevance of CCR2, CCL2, CCL7, CCL8, CCL13 and CCL16 were studied using human samples. The role of CCL2 in periodontitis was evaluated by using CCL2 knockout mice and overexpressing CCL2 in the periodontium. The effect of local administration of bindarit in periodontitis was evaluated by preventive and therapeutic medication in a mouse periodontitis model. Microcomputed tomography, haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, bead-based immunoassays and flow cytometry were used for histomorphology, molecular biology and cytology analysis.

RESULTS

Among different ligands of CCR2, only CCL2 was significantly up-regulated in periodontitis gingival tissues and was positively correlated with the severity of periodontitis. Mice lacking CCL2 showed milder inflammation and less bone resorption than wild-type mice, which was accompanied by a reduction in monocyte/macrophage recruitment. Adeno-associated virus-2 vectors overexpressing CCL2 in Ccl2-/- mice gingiva reversed the attenuation of periodontitis in a CCR2-dependent manner. In ligation-induced experimental periodontitis, preventive or therapeutic administration of bindarit, a CCL2 synthesis inhibitor, significantly inhibited the production of CCL2, decreased the osteoclast number and bone loss and reduced the expression levels of proinflammatory cytokines TNF-α, IL-6 and IL-1β.

CONCLUSIONS

CCL2 is a pivotal chemokine that binds to CCR2 during the progression of periodontitis, and targeting CCL2 may be a feasible option for controlling periodontitis.

Effect of Flavonoids on MCP-1 Expression in Human Coronary Artery Endothelial Cells and Impact on MCP-1-Dependent Migration of Human Monocytes

The monocyte chemoattractant protein-1 (MCP-1), also known as chemokine (CC motif) ligand 2 (CCL2), is involved in the formation, progression, and destabilization of atheromatous plaques. Flavonoids, found in fruits and vegetables, have been associated with various health-promoting properties, including antioxidant, anti-inflammatory, and cardioprotective effects. In the present study, the flavonoids quercetin, kaempferol, and luteolin, but not cannflavin A, were shown to substantially inhibit interleukin (IL)-1β-induced MCP-1 mRNA and protein expression in human coronary artery endothelial cells (HCAEC). At the functional level, conditioned medium (CM) from IL-1β-stimulated HCAEC caused an increase in the migration of THP-1 monocytes compared with CM from unstimulated HCAEC. However, this induction was suppressed when IL-1β-treated HCAEC were coincubated with quercetin, kaempferol, or luteolin. The functional importance of MCP-1 in IL-1β-induced monocyte migration was supported by experiments showing that neutralization of MCP-1 in the CM of IL-1β-treated HCAEC led to a significant inhibition of migration. In addition, a concentration-dependent induction of monocyte migration in the presence of recombinant MCP-1 was demonstrated. Collectively, the flavonoids quercetin, kaempferol, and luteolin were found to exert potential antiatherogenic effects in HCAEC, challenging further studies with these compounds.

Mural cell-derived chemokines provide a protective niche to safeguard vascular macrophages and limit chronic inflammation

Maladaptive, non-resolving inflammation contributes to chronic inflammatory diseases such as atherosclerosis. Because macrophages remove necrotic cells, defective macrophage programs can promote chronic inflammation with persistent tissue injury. Here, we investigated the mechanisms sustaining vascular macrophages. Intravital imaging revealed a spatiotemporal macrophage niche across vascular beds alongside mural cells (MCs)-pericytes and smooth muscle cells. Single-cell transcriptomics, co-culture, and genetic deletion experiments revealed MC-derived expression of the chemokines CCL2 and MIF, which actively preserved macrophage survival and their homeostatic functions. In atherosclerosis, this positioned macrophages in viable plaque areas, away from the necrotic core, and maintained a homeostatic macrophage phenotype. Disruption of this MC-macrophage unit via MC-specific deletion of these chemokines triggered detrimental macrophage relocalizing, exacerbated plaque necrosis, inflammation, and atheroprogression. In line, CCL2 inhibition at advanced stages of atherosclerosis showed detrimental effects. This work presents a MC-driven safeguard toward maintaining the homeostatic vascular macrophage niche.

The roles of chemokines following intracerebral hemorrhage in animal models and humans

Intracerebral hemorrhage (ICH) is one common yet devastating stroke subtype, imposing considerable burdens on families and society. Current guidelines are limited to symptomatic treatments after ICH, and the death rate remains significant in the acute stage. Thus, it is crucial to promote research to develop new targets on brain injury after ICH. In response to hematoma formation, amounts of chemokines are released in the brain, triggering the infiltration of resident immune cells in the brain and the chemotaxis of peripheral immune cells via the broken blood-brain barrier. During the past decades, mounting studies have focused on the roles of chemokines and their receptors in ICH injury. This review summarizes the latest advances in the study of chemokine functions in the ICH. First, we provide an overview of ICH epidemiology and underlying injury mechanisms in the pathogenesis of ICH. Second, we introduce the biology of chemokines and their receptors in brief. Third, we outline the roles of chemokines in ICH according to subgroups, including CCL2, CCL3, CCL5, CCL12, CCL17, CXCL8, CXCL12, and CX3CL1. Finally, we summarize current drug usage targeting chemokines in ICH and other cardio-cerebrovascular diseases. This review discusses the expressions of these chemokines and receptors under normal or hemorrhagic conditions and cell-specific sources. Above all, we highlight the related data of these chemokines in the progression and outcomes of the ICH disease in preclinical and clinical studies and point to therapeutic opportunities targeting chemokines productions and interactions in treating ICH, such as accelerating hematoma absorption and alleviating brain edema.

Role of the CCL2-CCR2 axis in cardiovascular disease: Pathogenesis and clinical implications

The CCL2-CCR2 axis is one of the major chemokine signaling pathways that has received special attention because of its function in the development and progression of cardiovascular disease. Numerous investigations have been performed over the past decades to explore the function of the CCL2-CCR2 signaling axis in cardiovascular disease. Laboratory data on the CCL2-CCR2 axis for cardiovascular disease have shown satisfactory outcomes, yet its clinical translation remains challenging. In this article, we describe the mechanisms of action of the CCL2-CCR2 axis in the development and evolution of cardiovascular diseases including heart failure, atherosclerosis and coronary atherosclerotic heart disease, hypertension and myocardial disease. Laboratory and clinical data on the use of the CCL2-CCR2 pathway as a targeted therapy for cardiovascular diseases are summarized. The potential of the CCL2-CCR2 axis in the treatment of cardiovascular diseases is explored.

Bindarit Reduces Bone Loss in Ovariectomized Mice by Inhibiting CCL2 and CCL7 Expression via the NF-κB Signaling Pathway

OBJECTIVE

To investigate the changes in proinflammatory cytokines and chemokines, namely, C-C motif ligand (CCL) 2 and CCL7, in postmenopausal osteoporosis (PMOP) and to develop a new drug, bindarit (Bnd), for PMOP in an ovariectomized (OVX) mouse model.

METHODS

Bone marrow macrophages (BMMs) from the femurs of five women with PMOP and five premenopausal women without osteoporosis were detected by RNA sequencing. BMMs from mice were differentiated into osteoclasts and treated with a synthetic inhibitor of CCL2 and CCL7, Bnd, or 17 beta estradiol (E2 ). Mouse BMMs were differentiated into osteoclasts with or without Bnd for 7 days and analyzed by RNA sequencing. Osteoblasts of mice were induced to undergo osteoblastogenesis and treated with Bnd. OVX mice were treated with E2 or Bnd after surgery. The protein and mRNA expression of CCL2 and CCL7 was detected using immunostaining and qPCR, respectively, in OVX and aged mice and in cells cultured in vitro. Osteoclast formation was detected using a tartrate-resistant acid phosphatase (TRAP) assay in vitro and in vivo. Alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN) were detected using immunostaining to evaluate osteogenesis. Microcomputed tomography was conducted to analyze trabecular bone parameters, the structure model index, bone mineral density and other variables. Nuclear factor-κB (NF-κB) signaling pathway-related protein phosphorylation of IKKα/β (p-IKKα/β) and p-NFκB p65 was examined using western blotting.

RESULTS

CCL2, CCL7 and their receptor of C-C chemokine receptor-2 (CCR2), and the NF-κB signaling pathway, were significantly increased in women with PMOP. CCL2 and CCL7 protein and mRNA expression was increased in OVX mice and aged female mice, but the increases were attenuated by E2 and Bnd. E2 and Bnd effectively inhibited osteoclastogenesis and the protein expression of CCL2 and CCL7 both in vitro and in vivo and reduced bone loss in OVX mice. Bnd did not affect the mineralization of osteoblasts directly in vitro but reduced bone turnover in vivo. p-IKKα/β and p-NFκB p65 levels were increased in BMMs of mice after differentiation into osteoclasts but were significantly decreased by Bnd.

CONCLUSION

The proinflammatory cytokines and chemokines CCL2, CCL7 and CCR2 were correlated with PMOP. Bnd attenuated the increases in CCL2 and CCL7 levels to affect osteoporosis in OVX mice via the NFκB signaling pathway. Thus, Bnd may be useful as a new therapeutic for the prevention of PMOP.

Targeting the CCL2-CCR2 axis for atheroprotection

Decades of research have established atherosclerosis as an inflammatory disease. Only recently though, clinical trials provided proof-of-concept evidence for the efficacy of anti-inflammatory strategies with respect to cardiovascular events, thus offering a new paradigm for lowering residual vascular risk. Efforts to target the inflammasome-interleukin-1β-interleukin-6 pathway have been highly successful, but inter-individual variations in drug response, a lack of reduction in all-cause mortality, and a higher rate of infections also highlight the need for a second generation of anti-inflammatory agents targeting atherosclerosis-specific immune mechanisms while minimizing systemic side effects. CC-motif chemokine ligand 2/monocyte-chemoattractant protein-1 (CCL2/MCP-1) orchestrates inflammatory monocyte trafficking between the bone marrow, circulation, and atherosclerotic plaques by binding to its cognate receptor CCR2. Adding to a strong body of data from experimental atherosclerosis models, a coherent series of recent large-scale genetic and observational epidemiological studies along with data from human atherosclerotic plaques highlight the relevance and therapeutic potential of the CCL2-CCR2 axis in human atherosclerosis. Here, we summarize experimental and human data pinpointing the CCL2-CCR2 pathway as an emerging drug target in cardiovascular disease. Furthermore, we contextualize previous efforts to interfere with this pathway, scrutinize approaches of ligand targeting vs. receptor targeting, and discuss possible pathway-intrinsic opportunities and challenges related to pharmacological targeting of the CCL2-CCR2 axis in human atherosclerotic disease.

Highly Selective PPARα (Peroxisome Proliferator-Activated Receptor α) Agonist Pemafibrate Inhibits Stent Inflammation and Restenosis Assessed by Multimodality Molecular-Microstructural Imaging

BACKGROUND

New pharmacological approaches are needed to prevent stent restenosis. This study tested the hypothesis that pemafibrate, a novel clinical selective PPARα (peroxisome proliferator‐activated receptor α) agonist, suppresses coronary stent‐induced arterial inflammation and neointimal hyperplasia.

METHODS AND RESULTS

Yorkshire pigs randomly received either oral pemafibrate (30 mg/day; n=6) or control vehicle (n=7) for 7 days, followed by coronary arterial implantation of 3.5 × 12 mm bare metal stents (2–4 per animal; 44 stents total). On day 7, intracoronary molecular‐structural near‐infrared fluorescence and optical coherence tomography imaging was performed to assess the arterial inflammatory response, demonstrating that pemafibrate reduced stent‐induced inflammatory protease activity (near‐infrared fluorescence target‐to‐background ratio: pemafibrate, median [25th‐75th percentile]: 2.8 [2.5–3.3] versus control, 4.1 [3.3–4.3], P=0.02). At day 28, animals underwent repeat near‐infrared fluorescence–optical coherence tomography imaging and were euthanized, and coronary stent tissue molecular and histological analyses. Day 28 optical coherence tomography imaging showed that pemafibrate significantly reduced stent neointima volume (pemafibrate, 43.1 [33.7–54.1] mm³ versus control, 54.2 [41.2–81.1] mm³; P=0.03). In addition, pemafibrate suppressed day 28 stent‐induced cellular inflammation and neointima expression of the inflammatory mediators TNF‐α (tumor necrosis factor‐α) and MMP‐9 (matrix metalloproteinase 9) and enhanced the smooth muscle differentiation markers calponin and smoothelin. In vitro assays indicated that the STAT3 (signal transducer and activator of transcription 3)–myocardin axes mediated the inhibitory effects of pemafibrate on smooth muscle cell proliferation.

CONCLUSIONS

Pemafibrate reduces preclinical coronary stent inflammation and neointimal hyperplasia following bare metal stent deployment. These results motivate further trials evaluating pemafibrate as a new strategy to prevent clinical stent restenosis.

Key Chemokine Pathways in Atherosclerosis and Their Therapeutic Potential

The search to improve therapies to prevent or treat cardiovascular diseases (CVDs) rages on, as CVDs remain a leading cause of death worldwide. Here, the main cause of CVDs, atherosclerosis, and its prevention, take center stage. Chemokines and their receptors have long been known to play an important role in the pathophysiological development of atherosclerosis. Their role extends from the initiation to the progression, and even the potential regression of atherosclerotic lesions. These important regulators in atherosclerosis are therefore an obvious target in the development of therapeutic strategies. A plethora of preclinical studies have assessed various possibilities for targeting chemokine signaling via various approaches, including competitive ligands and microRNAs, which have shown promising results in ameliorating atherosclerosis. Developments in the field also include detailed imaging with tracers that target specific chemokine receptors. Lastly, clinical trials revealed the potential of various therapies but still require further investigation before commencing clinical use. Although there is still a lot to be learned and investigated, it is clear that chemokines and their receptors present attractive yet extremely complex therapeutic targets. Therefore, this review will serve to provide a general overview of the connection between various chemokines and their receptors with atherosclerosis. The different developments, including mouse models and clinical trials that tackle this complex interplay will also be explored.

Targeting the chemokine network in atherosclerosis

Chemokines and their receptors represent a potential target for immunotherapy in chronic inflammation. They comprise a large family of cytokines with chemotactic activity, and their cognate receptors are expressed on all cells of the body. This network dictates leukocyte recruitment and activation, angiogenesis, cell proliferation and maturation. Dysregulation of chemokine and chemokine receptor expression as well as function participates in many pathologies including cancer, autoimmune diseases and chronic inflammation. In atherosclerosis, a lipid-driven chronic inflammation of middle-sized and large arteries, chemokines and their receptors participates in almost all stages of the disease from initiation of fatty streaks to mature atherosclerotic plaque formation. Atherosclerosis and its complications are the main driver of mortality and morbidity in cardiovascular diseases (CVD). Hence, exploring new fields of therapeutic targeting of atherosclerosis is of key importance. This review gives an overview of the recent advances on the role of key chemokines and chemokine receptors in atherosclerosis, addresses chemokine-based biomarkers at biochemical, imaging and genetic level in human studies, and highlights the clinial trials targeting atherosclerosis.

Complex Interplay of Genes Underlies Invasiveness in Fibrosarcoma Progression Model

Sarcomas are a heterogeneous group of mesenchymal tumours, with a great variability in their clinical behaviour. While our knowledge of sarcoma initiation has advanced rapidly in recent years, relatively little is known about mechanisms of sarcoma progression. JUN-murine fibrosarcoma progression series consists of four sarcoma cell lines, JUN-1, JUN-2, JUN-2fos-3, and JUN-3. JUN-1 and -2 were established from a single tumour initiated in a H2K/v-jun transgenic mouse, JUN-3 originates from a different tumour in the same animal, and JUN-2fos-3 results from a targeted in vitro transformation of the JUN-2 cell line. The JUN-1, -2, and -3 cell lines represent a linear progression from the least transformed JUN-2 to the most transformed JUN-3, with regard to all the transformation characteristics studied, while the JUN-2fos-3 cell line exhibits a unique transformation mode, with little deregulation of cell growth and proliferation, but pronounced motility and invasiveness. The invasive sarcoma sublines JUN-2fos-3 and JUN-3 show complex metabolic profiles, with activation of both mitochondrial oxidative phosphorylation and glycolysis and a significant increase in spared respiratory capacity. The specific transcriptomic profile of invasive sublines features very complex biological relationships across the identified genes and proteins, with accentuated autocrine control of motility and angiogenesis. Pharmacologic inhibition of one of the autocrine motility factors identified, Ccl8, significantly diminished both motility and invasiveness of the highly transformed fibrosarcoma cell. This progression series could be greatly valuable for deciphering crucial aspects of sarcoma progression and defining new prognostic markers and potential therapeutic targets.

C-C motif ligand 8 promotes atherosclerosis via NADPH oxidase 2/reactive oxygen species-induced endothelial permeability increase

Chemokines have been reported to play important roles in atherosclerotic development. Recently, we found C-C motif ligand 8 (CCL8), a rarely studied chemokine in atherosclerosis, was highly expressed in the endothelium of advanced human carotid plaques. We hypothesized whether CCL8 promotes atherosclerosis through endothelial dysfunction. Apolipoprotein E-deficient mice under the Western diet were used to construct atherosclerosis models. Adeno-associated viruses (AAV) with CCL8 and the CCL8-antibody were injected into mice respectively to conduct CCL8 overexpression and suppression. The results showed that atherosclerotic lesions were significantly increased in the AAV-CCL8 group, while, lesions in the aortic sinus were reduced in the CCL8-antibody group. With CCL8 treatment (200 ng/ml, 24 h) in vitro, the permeability of human aortic endothelial cells (HAECs) increased and the expression of junctional proteins Zonula occluden-1, and Vascular endothelial cadherin were decreased. This effect was dependent on reactive oxygen species (ROS) generation, which could be blocked by l-Ascorbic acid and Apocynin. Results showed that NADPH oxidase 2 (NOX2) expression also increased with CCL8 stimulation and the ROS, and permeability increase of HAECs could be inhibited when NOX2 interfered with the specific siRNA. Additionally, we further found ERK1/2, PI3K-AKT, and NF-κB pathways were involved in the activation of CCL8. Our results indicated that CCL8 might also play important roles in atherosclerosis and this effect, at least in part, was caused by NOX2/ROS-induced endothelial permeability increase. This study might contribute to a deeper understanding of the connection between chemokines and atherosclerosis.

Inflammatory Cell Recruitment in Cardiovascular Disease

Atherosclerosis, the main underlying pathology for myocardial infarction and stroke, is a chronic inflammatory disease of middle-sized to large arteries that is initiated and maintained by leukocytes infiltrating into the subendothelial space. It is now clear that the accumulation of pro-inflammatory leukocytes drives progression of atherosclerosis, its clinical complications, and directly modulates tissue-healing in the infarcted heart after myocardial infarction. This inflammatory response is orchestrated by multiple soluble mediators that enhance inflammation systemically and locally, as well as by a multitude of partially tissue-specific molecules that regulate homing, adhesion, and transmigration of leukocytes. While numerous experimental studies in the mouse have refined our understanding of leukocyte accumulation from a conceptual perspective, only a few anti-leukocyte therapies have been directly validated in humans. Lack of tissue-tropism of targeted factors required for leukocyte accumulation and unspecific inhibition strategies remain the major challenges to ultimately translate therapies that modulate leukocytes accumulation into clinical practice. Here, we carefully describe receptor and ligand pairs that guide leukocyte accumulation into the atherosclerotic plaque and the infarcted myocardium, and comment on potential future medical therapies.

Primer on the Pathogenesis of Severe COVID-19: Part Two

In the following continuation article, the author will expand on how the mechanisms discussed in Part One capitalise on host characteristics to produce the organ specific damage seen in severe coronavirus disease (COVID-19), with specific reference to pulmonary and cardiac manifestations. Pneumonia is the primary manifestation of COVID-19; presentation varies from a mild, self-limiting pneumonitis to a fulminant and progressive respiratory failure. Features of disease severity tend to directly correlate with patient age, with elderly populations faring poorest. Advancing age parallels an increasingly pro-oxidative pulmonary milieu, a consequence of increasing host expression of phospholipase A2 Group IID. Virally induced expression of NADPH oxidase intensifies this pro-oxidant environment. The virus avails of the host response by exploiting caveolin-1 to assist in disabling host defenses and adopting a glycolytic metabolic pathway to self-replicate.

Inhibition of CCL2 by bindarit alleviates diabetes-associated periodontitis by suppressing inflammatory monocyte infiltration and altering macrophage properties

Diabetes-associated periodontitis (DP) aggravates diabetic complications and increases mortality from diabetes. DP is caused by diabetes-enhanced host immune-inflammatory responses to bacterial insult. In this study, we found that persistently elevated CCL2 levels in combination with proinflammatory monocyte infiltration of periodontal tissues were closely related to DP. Moreover, inhibition of CCL2 by oral administration of bindarit reduced alveolar bone loss and increased periodontal epithelial thickness by suppressing periodontal inflammation. Furthermore, bindarit suppressed the infiltration of proinflammatory monocytes and altered the inflammatory properties of macrophages in the diabetic periodontium. This finding provides a basis for the development of an effective therapeutic approach for treating DP.

Chemokines as Therapeutic Targets in Cardiovascular Disease

With the incidence and impact of atherosclerotic cardiovascular disease and its clinical manifestations still rising, therapeutic options that target the causal mechanisms of this disorder are highly desired. Since the CANTOS trial (Canakinumab Antiinflammatory Thrombosis Outcome Study) has demonstrated that lowering inflammation can be beneficial, focusing on mechanisms underlying inflammation, for example, leukocyte recruitment, is feasible. Being key orchestrators of leukocyte trafficking, chemokines have not lost their attractiveness as therapeutic targets, despite the difficult road to drug approval thus far. Still, innovative therapeutic approaches are being developed, paving the road towards the first chemokine-based therapeutic against inflammation. In this overview, recent developments for chemokines and for the chemokine-like factor MIF (macrophage migration inhibitory factor) will be discussed.