Myeloid CD40 deficiency reduces atherosclerosis by impairing macrophages' transition into a pro-inflammatory state

The immune checkpoint regulator CD40 potentiates myocardial inflammation

Immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1, PD-L1 and CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here we leverage genetic mouse models, single-cell sequencing and cell depletion studies to show that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2+ macrophages and subsequent recruitment of effector memory CD8+ T cells. We identify a positive feedback loop between CCR2+ macrophages (positive for the chemokine receptor CCR2) and CD8+ T cells driven by IL-12b, TNF and IFNγ signaling that promotes myocardial inflammation and show that previous exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates left ventricular remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.

CD40-TRAF6 inhibition suppresses cardiovascular inflammation, oxidative stress and functional complications in a mouse model of arterial hypertension

Cardiovascular disease is the leading cause of disease burden and death worldwide and is fueled by vascular inflammation. CD40L-CD40-TRAF signaling is involved in the progression of atherosclerosis and drives the development of coronary heart disease (CHD). The present study investigates whether the CD40L-CD40-TRAF6 signaling pathway with focus on immune cells and adipocytes could be a therapeutic target in arterial hypertension. Arterial hypertension was induced in WT (C57BL6/J) and cell-specific CD40(L) knockout mice (AdipoqCre x CD40 fl/fl, CD4Cre x CD40 fl/fl, CD19Cre x CD40 fl/fl, and GP1baCre x CD40L fl/fl) via angiotensin (AT-II) infusion (1 mg/kg/d) for seven days. Hypertensive WT mice were also treated with a CD40-TRAF6 inhibitor (2.5 mg/kg/d, for 7d). The TRAF6 inhibitor treatment normalized endothelial dysfunction and reduced blood pressure in hypertensive wild type animals. Reactive oxygen species production was decreased by TRAF6 inhibition in blood, aorta, heart, kidney, and perivascular fat tissue. Additionally, FACS analysis revealed that TRAF6 inhibition prevents immune cell migration into the aortic vessel wall observed by reduced CD45+ leukocyte, Ly6G+/Ly6C+ neutrophil, and Ly6Chigh inflammatory monocyte content. The hypertensive cell type-specific CD40(L) knockout animals showed only a minor effect on endothelial function, blood pressure, and oxidative stress. Therefore, we conclude that targeting CD40 directly on adipocytes, B-cells, T-cells, or CD40L on platelets is not a promising target to prevent hypertension complications. In summary, TRAF6 inhibition but not adipocyte, B-cell, or T-cell-specific CD40 or platelet-specific CD40L deficiency reduces pathophysiological vascular inflammation in hypertensive mice, suggesting TRAF6 inhibition as a potential therapeutic target in hypertensive patients.

Unravelling molecular mechanisms in atherosclerosis using cellular models and omics technologies

Despite the discovery and prevalent clinical use of potent lipid-lowering therapies, including statins and PCSK9 inhibitors, cardiovascular diseases (CVD) caused by atherosclerosis remain a large unmet clinical need, accounting for frequent deaths worldwide. The pathogenesis of atherosclerosis is a complex process underlying the presence of modifiable and non-modifiable risk factors affecting several cell types including endothelial cells (ECs), monocytes/macrophages, smooth muscle cells (SMCs) and T cells. Heterogeneous composition of the plaque and its morphology could lead to rupture or erosion causing thrombosis, even a sudden death. To decipher this complexity, various cell model systems have been developed. With recent advances in systems biology approaches and single or multi-omics methods researchers can elucidate specific cell types, molecules and signalling pathways contributing to certain stages of disease progression. Compared with animals, in vitro models are economical, easily adjusted for high-throughput work, offering mechanistic insights. Hereby, we review the latest work performed employing the cellular models of atherosclerosis to generate a variety of omics data. We summarize their outputs and the impact they had in the field. Challenges in the translatability of the omics data obtained from the cell models will be discussed along with future perspectives.

Macrophages Unmasked: Their Pivotal Role in Driving Atherosclerosis in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that significantly increases the risk of cardiovascular diseases, particularly atherosclerosis (AS). Understanding the shared pathogenic mechanisms underlying SLE and AS is crucial for developing effective therapeutic strategies. Macrophages, as pivotal immune cells, play a critical role in the initiation and progression of atherosclerotic plaques within the context of SLE. This review delves into the molecular and cellular mechanisms governing macrophage activation and differentiation in response to SLE-related inflammatory mediators, highlighting their roles in lipid metabolism, plaque stability, and immune regulation. Additionally, we discussed the current treatment modalities for SLE and their impact on macrophage functionality, exploring these effects for atherosclerotic progression. By elucidating the intricate relationship between macrophages, SLE pathophysiology, and AS progression, this review underscores the need for a multidisciplinary approach in managing SLE and its cardiovascular complications, aiming to improve patient survival and quality of life through tailored therapeutic interventions addressing both autoimmune and cardiovascular pathologies.

SOX11 silence inhibits atherosclerosis progression in ApoE-deficient mice by alleviating endothelial dysfunction

SRY-Box Transcription Factor-11 (SOX11) is a transcriptional regulatory factor that plays a crucial role in inflammatory responses. However, its involvement in atherosclerosis (AS), a cardiovascular disease driven by endothelial cell inflammation, remains unknown. This study aims to elucidate the role of SOX11 in AS. The expression of SOX11 was found to be elevated in the aortic tissue of AS mice induced by feeding ApoE-deficient mice a high-fat diet. Knockdown of SOX11 using lentiviral-mediated SOX11-specific shRNA via tail vein injection resulted in a reduction in plaque area and lipid deposition within plaques at the aortic root. Furthermore, silencing SOX11 led to decreased expression of cell adhesion factors Intercellular Cell Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1, as well as reduced levels of inflammatory factors Interleukin (IL)-6, IL-1β, and chemokine Monocyte Chemotactic Protein-1. In the human umbilical vein endothelial cells (HUVECs) induced by Tumor Necrosis Factor (TNF)-α, increased inflammation was observed at the cellular level, along with enhanced monocyte adhesion. Infection of HUVECs with lentivirus carrying specific shRNA targeting SOX11 inhibited inflammatory response. Mechanistically, chromatin immunoprecipitation (ChIP)-PCR results revealed that SOX11 bound to the promoters of downstream target genes Tumor Necrosis Factor Receptor-Associated Factor-1 (TRAF1), Cluster of Differentiation (CD)40, and CD36, positively regulating their transcription. In conclusion, SOX11 plays a pivotal role in promoting endothelial cell inflammation. Suppression of SOX11 reduces endothelial cell inflammation by inhibiting the transcription of TRAF1, CD40, and CD36, thereby impeding the progression of atherosclerosis.

Advancements in adoptive CAR immune cell immunotherapy synergistically combined with multimodal approaches for tumor treatment

Adoptive immunotherapy, notably involving chimeric antigen receptor (CAR)-T cells, has obtained Food and Drug Administration (FDA) approval as a treatment for various hematological malignancies, demonstrating promising preclinical efficacy against cancers. However, the intricate and resource-intensive autologous cell processing, encompassing collection, expansion, engineering, isolation, and administration, hamper the efficacy of this therapeutic modality. Furthermore, conventional CAR T therapy is presently confined to addressing solid tumors due to impediments posed by physical barriers, the potential for cytokine release syndrome, and cellular exhaustion induced by the immunosuppressive and heterogeneous tumor microenvironment. Consequently, a strategic integration of adoptive immunotherapy with synergistic multimodal treatments, such as chemotherapy, radiotherapy, and vaccine therapy etc., emerges as a pivotal approach to surmount these inherent challenges. This collaborative strategy holds the key to addressing the limitations delineated above, thereby facilitating the realization of more precise personalized therapies characterized by heightened therapeutic efficacy. Such synergistic strategy not only serves to mitigate the constraints associated with adoptive immunotherapy but also fosters enhanced clinical applicability, thereby advancing the frontiers of therapeutic precision and effectiveness.

Role of the NOD1/Rip2 Signaling Pathway in Macrophage Inflammatory Activation Induced by ox-LDL

Aim: This study aimed to investigate the impact of the NOD1/Rip2 signaling pathway on macrophage inflammatory activation and polarity switching in ox-LDL-induced THP-1-derived macrophages. Methods: THP-1-derived macrophages were stimulated with various concentrations (10, 25, or 50 mg/L) of ox-LDL for different durations (8, 16, or 24 h). Quantitative real-time PCR was used to measure the mRNA expression of NOD1, Rip2, IL-10, IL-12, iNOS, and Arg-1. Western blotting was used to determine the protein levels of NOD1 and Rip2. The secretion of TNF-α and MCP-1 in the cell culture supernatants was measured via ELISA. Rip2 siRNA was used to inhibit the NOD1/Rip2 signaling pathway. Oil Red O staining was employed to visualize foam cell formation. CD86, CD80, and CD163 membrane molecules were analyzed via FACS. Results: After exposure to ox-LDL, the expression levels of NOD1 and Rip2 mRNAs and proteins in THP-1-derived macrophages increased in a dose- and time-dependent manner. This upregulation was accompanied by increased concentrations of TNF-α and MCP-1 in the cell culture supernatants. The effects of NOD1 and Rip2 expression upregulation were mitigated by Rip2 siRNA, as evidenced by decreased concentrations of TNF-α and MCP-1. Furthermore, ox-LDL downregulated the expression of M2 macrophage markers CD163, IL-12, and Arg-1 and upregulated the expression of M1 macrophage markers CD86, CD80, IL-10, and iNOS. The inhibition of Rip2 by siRNA reversed these effects and prevented the formation of foam cells. Conclusion: Our data show that the NOD1/RIP2 signaling pathway regulates the inflammatory activation of macrophages induced by ox-LDL and controls the macrophage polarity switch.

Costimulatory and Coinhibitory Immune Checkpoints in Atherosclerosis: Therapeutic Targets in Atherosclerosis?

The benefits of current state-of-the-art treatments to combat atherosclerotic cardiovascular disease (ASCVD) have stagnated. Treatments are mostly based on controlling cardiovascular risk factors, especially hyperlipidemia. Although the most recent advances with PCSK-9 inhibitors support the hyperlipidemia aspect of ASCVD, several lines of experimental evidence have outlined that atherosclerosis is also driven by inflammation. In the past years, phase 1, 2, and 3 clinical trials targeting inflammation to combat ASCVD have revealed that patients do tolerate such immune therapies, show decreases in inflammatory markers, and/or have reductions in cardiovascular endpoints. However, the search for the optimal anti-inflammatory or immune-modulating strategy and the stratification of patients who would benefit from such treatments and appropriate treatment regimens to combat ASCVD is only just beginning. In this review, we focus on immune checkpoint-based therapeutics (costimulation and coinhibition), many of which are already approved by the U.S. Food and Drug Administration for the treatment of cancer or autoimmune diseases, and discuss their use as a novel immunotherapeutic strategy to treat ASCVD.

Co-stimulators CD40-CD40L, a potential immune-therapy target for atherosclerosis: A review

The interaction between CD40 and CD40 ligand (CD40L) a crucial co-stimulatory signal for activating adaptive immune cells, has a noteworthy role in atherosclerosis. It is well-known that atherosclerosis is linked to immune inflammation in blood vessels. In atherosclerotic lesions, there is a multitude of proinflammatory cytokines, adhesion molecules, and collagen, as well as smooth muscle cells, macrophages, and T lymphocytes, particularly the binding of CD40 and CD40L. Therefore, research on inhibiting the CD40-CD40L system to prevent atherosclerosis has been ongoing for more than 30 years. However, it's essential to note that long-term direct suppression of CD40 or CD40L could potentially result in immunosuppression, emphasizing the critical role of the CD40-CD40L system in atherosclerosis. Thus, specifically targeting the CD40-CD40L interaction on particular cell types or their downstream signaling pathways may be a robust strategy for mitigating atherosclerosis, reducing potential side effects. This review aims to summarize the potential utility of the CD40-CD40L system as a viable therapeutic target for atherosclerosis.

CD40 is an immune checkpoint regulator that potentiates myocardial inflammation through activation and expansion of CCR2 + macrophages and CD8 T-cells

Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.

Photodynamic Therapy for Atherosclerosis

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.

Par3L, a polarity protein, promotes M1 macrophage polarization and aggravates atherosclerosis in mice via p65 and ERK activation

Proinflammatory M1 macrophages are critical for the progression of atherosclerosis. The Par3-like protein (Par3L) is a homolog of the Par3 family involved in cell polarity establishment. Par3L has been shown to maintain the stemness of mammary stem cells and promote the survival of colorectal cancer cells. In this study, we investigated the roles of the polar protein Par3L in M1 macrophage polarization and atherosclerosis. To induce atherosclerosis, Apoe-/- mice were fed with an atherosclerotic Western diet for 8 or 16 weeks. We showed that Par3L expression was significantly increased in human and mouse atherosclerotic plaques. In primary mouse macrophages, oxidized low-density lipoprotein (oxLDL, 50 μg/mL) time-dependently increased Par3L expression. In Apoe-/- mice, adenovirus-mediated Par3L overexpression aggravated atherosclerotic plaque formation accompanied by increased M1 macrophages in atherosclerotic plaques and bone marrow. In mouse bone marrow-derived macrophages (BMDMs) or peritoneal macrophages (PMs), we revealed that Par3L overexpression promoted LPS and IFNγ-induced M1 macrophage polarization by activating p65 and extracellular signal-regulated kinase (ERK) rather than p38 and JNK signaling. Our results uncover a previously unidentified role for the polarity protein Par3L in aggravating atherosclerosis and favoring M1 macrophage polarization, suggesting that Par3L may serve as a potential therapeutic target for atherosclerosis.

Tissue-specific Cre driver mice to study vascular diseases

Vascular diseases, including atherosclerosis and abdominal aneurysms, are the primary cause of mortality and morbidity among the elderly worldwide. The life quality of patients is significantly compromised due to inadequate therapeutic approaches and limited drug targets. To expand our comprehension of vascular diseases, gene knockout (KO) mice, especially conditional knockout (cKO) mice, are widely used for investigating gene function and mechanisms of action. The Cre-loxP system is the most common method for generating cKO mice. Numerous Cre driver mice have been established to study the main cell types that compose blood vessels, including endothelial cells, smooth muscle cells, and fibroblasts. Here, we first discuss the characteristics of each layer of the arterial wall. Next, we provide an overview of the representative Cre driver mice utilized for each of the major cell types in the vessel wall and their most recent applications in vascular biology. We then go over Cre toxicity and discuss the practical methods for minimizing Cre interference in experimental outcomes. Finally, we look into the future of tissue-specific Cre drivers by introducing the revolutionary single-cell RNA sequencing and dual recombinase system.

Elevated circulating inflammatory biomarker levels in the SIRT1-NF-κB-sCD40L pathway in patients with acute myocardial infarction: a case-control study

BACKGROUND

Inflammation plays a key role in atherosclerosis development and progression. However, the role of novel inflammatory biomarker pathways, namely the SIRT1-NF-κB-sCD40L, in the etiopathogenesis of human atherosclerosis remains undefined. This study was designed to evaluate the changes and clinical implications of these inflammatory mediators in the plasma of patients with acute myocardial infarction (AMI).

METHODS

The peripheral arterial blood of 88 participants (68 patients with AMI and 20 age-matched controls), was drawn prior to performing coronary angiography (CAG). The SIRT1, NF-κB, and sCD40L plasma levels were quantified using ELISA. Spearman's analysis was used to evaluate the correlation between the three inflammatory markers, while Pearson's test assessed their potential correlation with cardiac troponin T (TNT) levels. Sensitivity, specificity, and area under the ROC curve (AUC) were calculated as measures of diagnostic accuracy.

RESULTS

Patients with AMI showed higher levels of circulating SIRT1, NF-κB, and sCD40L compared to the age-matched controls (p < 0.05). However, the plasma concentrations of these three inflammatory mediators did not differ between the ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) patients. Additionally, in patients with AMI, the SIRT1 level was positively correlated with NF-κB and sCD40L levels (p < 0.001). Likewise, the levels of SIRT1, NF-κB and sCD40L were positively correlated with TNT levels (p < 0.001). More importantly, the ROC analysis showed that the diagnostic accuracy of AMI was significantly higher when NF-κB or sCD40L level was used in combination with TNT levels (p < 0.05).

CONCLUSIONS

The levels of the circulating inflammatory biomarkers, including SIRT1, NF-κB, and sCD40L, were significantly elevated in patients with AMI. These novel biomarkers can improve the diagnostic accuracy of AMI when combined with TNT.KEY MESSAGESAMI is a potentially lethal CAD and is the leading cause of mortality and morbidity worldwide. Inflammation plays a key role in atherosclerosis development and progression. The levels of the circulating novel inflammatory biomarkers, including SIRT1, NF-κB, and sCD40L, were significantly elevated in patients with AMI.The SIRT1 level was positively correlated with NF-κB and sCD40L levels in patients with AMI.The levels of SIRT1, NF-κB and sCD40L were positively correlated with TNT levels.The ROC analysis showed that the diagnostic accuracy of AMI was significantly higher when NF-κB or sCD40L level was used in combination with TNT levels.SIRT1/NF-κB/sCD40L axis inhibition is a potential new target for AMI treatment.

Recent Advances in Folates and Autoantibodies against Folate Receptors in Early Pregnancy and Miscarriage

Though firstly identified in cerebral folate deficiency, autoantibodies against folate receptors (FRAbs) have been implicated in pregnancy complications such as miscarriage; however, the underlying mechanism needs to be further elaborated. FRAbs can be produced via sensitization mediated by folate-binding protein as well as gene mutation, aberrant modulation, or degradation of folate receptors (FRs). FRAbs may interfere with folate internalization and metabolism through blocking or binding with FRs. Interestingly, different types of FRs are expressed on trophoblast cells, decidual epithelium or stroma, and macrophages at the maternal-fetal interface, implying FRAbs may be involved in the critical events necessary for a successful pregnancy. Thus, we propose that FRAbs may disturb pregnancy establishment and maintenance by modulating trophoblastic biofunctions, placental development, decidualization, and decidua homeostasis as well as the functions of FOLR2+ macrophages. In light of these findings, FRAbs may be a critical factor in pathological pregnancy, and deserve careful consideration in therapies involving folic acid supplementation for pregnancy complications.

Membrane contact sites orchestrate cholesterol homeostasis that is central to vascular aging

Chronological age causes structural and functional vascular deterioration and is a well-established risk factor for the development of cardiovascular diseases, leading to more than 40% of all deaths in the elderly. The etiology of vascular aging is complex; a significant impact arises from impaired cholesterol homeostasis. Cholesterol level is balanced through synthesis, uptake, transport, and esterification, the processes executed by multiple organelles. Moreover, organelles responsible for cholesterol homeostasis are spatially and functionally coordinated instead of isolated by forming the membrane contact sites. Membrane contact, mediated by specific protein-protein interaction, pulls opposing organelles together and creates the hybrid place for cholesterol transfer and further signaling. The membrane contact-dependent cholesterol transfer, together with the vesicular transport, maintains cholesterol homeostasis and has intimate implications in a growing list of diseases, including vascular aging-related diseases. Here, we summarized the latest advances regarding cholesterol homeostasis by highlighting the membrane contact-based regulatory mechanism. We also describe the downstream signaling under cholesterol homeostasis perturbations, prominently in cholesterol-rich conditions, stimulating age-dependent organelle dysfunction and vascular aging. Finally, we discuss potential cholesterol-targeting strategies for therapists regarding vascular aging-related diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology.

T Cells in Atherosclerosis: Key Players in the Pathogenesis of Vascular Disease

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipid-rich plaques within arterial walls. T cells play a pivotal role in the pathogenesis of atherosclerosis in which they help orchestrate immune responses and contribute to plaque development and instability. Here, we discuss the recognition of atherosclerosis-related antigens that may trigger T cell activation together with additional signaling from co-stimulatory molecules and lesional cytokines. Although few studies have indicated candidates for the antigen specificity of T cells in atherosclerosis, further research is needed. Furthermore, we describe the pro-atherogenic and atheroprotective roles of diverse subsets of T cells such as CD4+ helper, CD8+ cytotoxic, invariant natural killer, and γδ T cells. To classify and quantify T cell subsets in atherosclerosis, we summarize current methods to analyze cellular heterogeneity including single cell RNA sequencing and T cell receptor (TCR) sequencing. Further insights into T cell biology will help shed light on the immunopathology of atherosclerosis, inform potential therapeutic interventions, and pave the way for precision medicine approaches in combating cardiovascular disease.

Adipocytes control hematopoiesis and inflammation through CD40 signaling

The co-stimulatory CD40-CD40L dyad plays an important role in chronic inflammatory diseases associated with aging. Although CD40 is mainly expressed by immune cells, CD40 is also present on adipocytes. We aimed to delineate the role of adipocyte CD40 in the aging hematopoietic system and evaluated the effects of adipocyte CD40 deficiency on cardiometabolic diseases. Adult adipocyte CD40-deficient mice (AdiCD40KO) mice had a decrease in bone marrow hematopoietic stem cells (Lin-Sca+cKit+, LSK) and common lymphoid progenitors, which was associated with increased bone marrow adiposity and T-cell activation, along with elevated plasma corticosterone levels, a phenotype that became more pronounced with age. Atherosclerotic AdiCD40koApoE-/- (CD40AKO) mice also displayed changes in the LSK population, showing increased myeloid and lymphoid multipotent progenitors, and augmented corticosterone levels. Increased T-cell activation could be observed in bone marrow, spleen, and adipose tissue, while the numbers of B cells were decreased. Although atherosclerosis was reduced in CD40AKO mice, plaques contained more activated T cells and larger necrotic cores. Analysis of peripheral adipose tissue in a diet-induced model of obesity revealed that obese AdiCD40KO mice had increased T-cell activation in adipose tissue and lymphoid organs, but decreased weight gain and improved insulin sensitivity, along with increased fat oxidation. In conclusion, adipocyte CD40 plays an important role in maintaining immune cell homeostasis in bone marrow during aging and chronic inflammatory diseases, particularly of the lymphoid populations. Although adipocyte CD40 deficiency reduces atherosclerosis burden and ameliorates diet-induced obesity, the accompanying T-cell activation may eventually aggravate cardiometabolic diseases.

Novel mechanisms and therapeutic targets in atherosclerosis: inflammation and beyond

This review based on the ESC William Harvey Lecture in Basic Science 2022 highlights recent experimental and translational progress on the therapeutic targeting of the inflammatory components in atherosclerosis, introducing novel strategies to limit side effects and to increase efficacy. Since the validation of the inflammatory paradigm in CANTOS and COLCOT, efforts to control the residual risk conferred by inflammation have centred on the NLRP3 inflammasome-driven IL-1β-IL6 axis. Interference with the co-stimulatory dyad CD40L-CD40 and selective targeting of tumour necrosis factor-receptor associated factors (TRAFs), namely the TRAF6-CD40 interaction in macrophages by small molecule inhibitors, harbour intriguing options to reduce established atherosclerosis and plaque instability without immune side effects. The chemokine system crucial for shaping immune cell recruitment and homoeostasis can be fine-tuned and modulated by its heterodimer interactome. Structure-function analysis enabled the design of cyclic, helical, or linked peptides specifically targeting or mimicking these interactions to limit atherosclerosis or thrombosis by blunting myeloid recruitment, boosting regulatory T cells, inhibiting platelet activity, or specifically blocking the atypical chemokine MIF without notable side effects. Finally, adventitial neuroimmune cardiovascular interfaces in advanced atherosclerosis show robust restructuring of innervation from perivascular ganglia and employ sensory neurons of dorsal root ganglia to enter the central nervous system and to establish an atherosclerosis-brain circuit sensor, while sympathetic and vagal efferents project to the celiac ganglion to create an atherosclerosis-brain circuit effector. Disrupting this circuitry by surgical or chemical sympathectomy limited disease progression and enhanced plaque stability, opening exciting perspectives for selective and tailored intervention beyond anti-inflammatory strategies.

Deficiency of germinal center kinase TRAF2 and NCK-interacting kinase (TNIK) in B cells does not affect atherosclerosis

Background

Atherosclerosis is the underlying cause of many cardiovascular diseases, such as myocardial infarction or stroke. B cells, and their production of pro- and anti-atherogenic antibodies, play an important role in atherosclerosis. In B cells, TRAF2 and NCK-interacting Kinase (TNIK), a germinal center kinase, was shown to bind to TNF-receptor associated factor 6 (TRAF6), and to be involved in JNK and NF-κB signaling in human B cells, a pathway associated with antibody production.

Objective

We here investigate the role of TNIK-deficient B cells in atherosclerosis.

Results

ApoE^-/-TNIK^fl/fl (TNIK^BWT) and ApoE^-/-TNIK^fl/flCD19-cre (TNIK^BKO) mice received a high cholesterol diet for 10 weeks. Atherosclerotic plaque area did not differ between TNIK^BKO and TNIK^BWT mice, nor was there any difference in plaque necrotic core, macrophage, T cell, α-SMA and collagen content. B1 and B2 cell numbers did not change in TNIK^BKO mice, and marginal zone, follicular or germinal center B cells were unaffected. Total IgM and IgG levels, as well as oxidation specific epitope (OSE) IgM and IgG levels, did not change in absence of B cell TNIK. In contrast, plasma IgA levels were decreased in TNIK^BKO mice, whereas the number of IgA⁺ B cells in intestinal Peyer's patches increased. No effects could be detected on T cell or myeloid cell numbers or subsets.

Conclusion

We here conclude that in hyperlipidemic ApoE^-/- mice, B cell specific TNIK deficiency does not affect atherosclerosis.

Atherosclerosis With Immune Checkpoint Inhibitor Therapy: Evidence, Diagnosis, and Management: JACC: CardioOncology State-of-the-Art Review

As the clinical applications of immune checkpoint inhibitors (ICIs) expand, our knowledge of the potential adverse effects of these drugs continues to broaden. Emerging evidence supports the association between ICI therapy with accelerated atherosclerosis and atherosclerotic cardiovascular (CV) events. We discuss the biological plausibility and the clinical evidence supporting an effect of inhibition of these immune checkpoints on atherosclerotic CV disease. Further, we provide a perspective on potential diagnostic and pharmacological strategies to reduce atherosclerotic risk in ICI-treated patients. Our understanding of the pathophysiology of ICI-related atherosclerosis is in its early stages. Further research is needed to identify the mechanisms linking ICI therapy to atherosclerosis, leverage the insight that ICI therapy provides into CV biology, and develop robust approaches to manage the expanding cohort of patients who may be at risk for atherosclerotic CV disease.

Antibodies in action: the role of humoral immunity in the fight against atherosclerosis

The sequestering of oxidation-modified low-density lipoprotein by macrophages results in the accumulation of fatty deposits within the walls of arteries. Necrosis of these cells causes a release of intercellular epitopes and the activation of the adaptive immune system, which we predict leads to robust autoantibody production. T cells produce cytokines that act in the plaque environment and further stimulate B cell antibody production. B cells in atherosclerosis meanwhile have a mixed role based on subclass. The current model is that B-1 cells produce protective IgM antibodies in response to oxidation-specific epitopes that work to control plaque formation, while follicular B-2 cells produce class-switched antibodies (IgG, IgA, and IgE) which exacerbate the disease. Over the course of this review, we discuss further the validation of these protective antibodies while evaluating the current dogma regarding class-switched antibodies in atherosclerosis. There are several contradictory findings regarding the involvement of class-switched antibodies in the disease. We hypothesize that this is due to antigen-specificity, and not simply isotype, being important, and that a closer evaluation of these antibodies' targets should be conducted. We propose that specific antibodies may have therapeutical potential in preventing and controlling plaque development within a clinical setting.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

Atherosclerosis and its clinical manifestations, coronary and cerebral artery diseases, are the most common cause of death worldwide. The main pathophysiological mechanism for these complications is the rupture of vulnerable atherosclerotic plaques and subsequent thrombosis. Pathological studies of the vulnerable lesions showed that more frequently, plaques rich in lipids and with a high level of inflammation, responsible for mild or moderate stenosis, are more prone to rupture, leading to acute events. Identifying the vulnerable plaques helps to stratify patients at risk of developing acute vascular events. Traditional imaging methods based on plaque appearance and size are not reliable in prediction the risk of rupture. Intravascular imaging is a novel technique able to identify vulnerable lesions, but it is invasive and an operator-dependent technique. This review aims to summarize the current data from literature regarding the main biomarkers involved in the attempt to diagnose vulnerable atherosclerotic lesions. These biomarkers could be the base for risk stratification and development of the new therapeutic drugs in the treatment of patients with vulnerable atherosclerotic plaques.

Role of CD40(L)-TRAF signaling in inflammation and resolution-a double-edged sword

Cardiovascular diseases (CVD) and cardiovascular risk factors are the leading cause of death in the world today. According to the Global Burden of Disease Study, hypertension together with ischemic heart and cerebrovascular diseases is responsible for approximately 40% of all deaths worldwide. The major pathomechanism underlying almost all CVD is atherosclerosis, an inflammatory disorder of the vascular system. Recent large-scale clinical trials demonstrated that inflammation itself is an independent cardiovascular risk factor. Specific anti-inflammatory therapy could decrease cardiovascular mortality in patients with atherosclerosis (increased markers of inflammation). Inflammation, however, can also be beneficial by conferring so-called resolution, a process that contributes to clearing damaged tissue from cell debris upon cell death and thereby represents an essential step for recovery from, e.g., ischemia/reperfusion damage. Based on these considerations, the present review highlights features of the detrimental inflammatory reactions as well as of the beneficial process of immune cell-triggered resolution. In this context, we discuss the polarization of macrophages to either M1 or M2 phenotype and critically assess the role of the CD40L-CD40-TRAF signaling cascade in atherosclerosis and its potential link to resolution. As CD40L can bind to different cellular receptors, it can initiate a broad range of inflammatory processes that may be detrimental or beneficial. Likewise, the signaling of CD40L downstream of CD40 is mainly determined by activation of TRAF1-6 pathways that again can be detrimental or beneficial. Accordingly, CD40(L)-based therapies may be Janus-faced and require sophisticated fine-tuning in order to promote cardioprotection.