Targeting interferon-gamma to treat atherosclerosis

Molecular fingerprints of cardiovascular toxicities of immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy by unleashing the power of the immune system against malignant cells. However, their use is associated with a spectrum of adverse effects, including cardiovascular complications, which can pose significant clinical challenges. Several mechanisms contribute to cardiovascular toxicity associated with ICIs. First, the dysregulation of immune checkpoints, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein-1 (PD-1) and its ligand (PD-L1), and molecular mimicry with cardiac autoantigens, leads to immune-related adverse events, including myocarditis and vasculitis. These events result from the aberrant activation of T cells against self-antigens within the myocardium or vascular endothelium. Second, the disruption of immune homeostasis by ICIs can lead to autoimmune-mediated inflammation of cardiac tissues, manifesting as cardiac dysfunction and heart failure, arrhythmias, or pericarditis. Furthermore, the upregulation of inflammatory cytokines, particularly tumor necrosis factor-alpha, interferon-γ, interleukin-1β, interleukin-6, and interleukin-17 contributes to cardiac and endothelial dysfunction, plaque destabilization, and thrombosis, exacerbating cardiovascular risk on the long term. Understanding the intricate mechanisms of cardiovascular side effects induced by ICIs is crucial for optimizing patient care and to ensure the safe and effective integration of immunotherapy into a broader range of cancer treatment protocols. The clinical implications of these mechanisms underscore the importance of vigilant monitoring and early detection of cardiovascular toxicity in patients receiving ICIs. Future use of these key pathological mediators as biomarkers may aid in prompt diagnosis of cardiotoxicity and will allow timely interventions.

Association between Immune Checkpoint Inhibitors and Atherosclerotic Cardiovascular Disease Risk: Another Brick in the Wall

In recent years, immune checkpoint inhibitors have significantly changed the field of oncology, emerging as first-line treatment, either alone or in combination with other regimens, for numerous malignancies, improving overall survival and progression-free survival in these patients. However, immune checkpoint inhibitors might also cause severe or fatal immune-related adverse events, including adverse cardiovascular events. Initially, myocarditis was recognized as the main immune checkpoint inhibitor-related cardiac event, but our knowledge of other potential immune-related cardiovascular adverse events continues to broaden. Recently, preclinical and clinical data seem to support an association between immune checkpoint inhibitors and accelerated atherosclerosis as well as atherosclerotic cardiovascular events such as cardiac ischemic disease, stroke, and peripheral artery disease. In this review, by offering a comprehensive overview of the pivotal role of inflammation in atherosclerosis, we focus on the potential molecular pathways underlying the effects of immune checkpoint inhibitors on cardiovascular diseases. Moreover, we provide an overview of therapeutic strategies for cancer patients undergoing immunotherapy to prevent the development of cardiovascular diseases.

Immune checkpoint inhibitors associated cardiovascular immune-related adverse events

Immune checkpoint inhibitors (ICIs) are specialized monoclonal antibodies (mAbs) that target immune checkpoints and their ligands, counteracting cancer cell-induced T-cell suppression. Approved ICIs like cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), its ligand PD-L1, and lymphocyte activation gene-3 (LAG-3) have improved cancer patient outcomes by enhancing anti-tumor responses. However, some patients are unresponsive, and others experience immune-related adverse events (irAEs), affecting organs like the lung, liver, intestine, skin and now the cardiovascular system. These cardiac irAEs include conditions like myocarditis, atherosclerosis, pericarditis, arrhythmias, and cardiomyopathy. Ongoing clinical trials investigate promising alternative co-inhibitory receptor targets, including T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) and T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT). This review delves into the mechanisms of approved ICIs (CTLA-4, PD-1, PD-L1, and LAG-3) and upcoming options like Tim-3 and TIGIT. It explores the use of ICIs in cancer treatment, supported by both preclinical and clinical data. Additionally, it examines the mechanisms behind cardiac toxic irAEs, focusing on ICI-associated myocarditis and atherosclerosis. These insights are vital as ICIs continue to revolutionize cancer therapy, offering hope to patients, while also necessitating careful monitoring and management of potential side effects, including emerging cardiac complications.

Interferon-gamma (IFN-γ): Reviewing its mechanisms and signaling pathways on the regulation of endothelial barrier function

Interferon-gamma (IFN-γ) is a pleiotropic cytokine that plays a critical role in mediating an array of immune responses including promotes antiviral activity, facilitates macrophage activation, controls Th1/Th2 balance, and regulates cellular apoptosis and proliferation. A few articles have previously reviewed the effects of IFN-γ in the regulation of barrier permeability, but none of these articles focuses on barrier function of endothelial cells. This review aims to discuss the regulatory mechanisms of IFN-γ on endothelial barrier function and its underlying signaling pathways. Articles were retrieved from electronic databases such as PubMed and Google Scholar using keywords "Interferon-gamma", "endothelial cells", "barrier function", and "signaling pathway". The articles published between 2000 and 2022 that are related to the aforementioned topics were selected. A few journals published beyond this period were also included due to limited information available. The results showed that IFN-γ modulates endothelial barrier function, mainly involves small GTPases, STAT1-dependent pathway, p38 MAPK and nitric oxide. In conclusion, more in depth cellular and molecular studies are needed to elucidate the pathways of IFN-γ in the regulation of endothelial barrier function.

The role of immune checkpoints in cardiovascular disease

Immune checkpoint inhibitors (ICI) are monoclonal antibodies which bind to immune checkpoints (IC) and their ligands to prevent inhibition of T-cell activation by tumor cells. Currently, multiple ICI are approved targeting Cytotoxic T-lymphocyte antigen 4 (CTLA-4), Programmed Death Protein 1 (PD-1) and its ligand PD-L1, and Lymphocyte-activation gene 3 (LAG-3). This therapy has provided potent anti-tumor effects and improved prognosis for many cancer patients. However, due to systemic effects, patients can develop immune related adverse events (irAE), including possible life threatening cardiovascular irAE, like atherosclerosis, myocarditis and cardiomyopathy. Inhibition of vascular IC is associated with increased atherosclerotic burden and plaque instability. IC protect against atherosclerosis by inhibiting T-cell activity and cytokine production, promoting regulatory T-cell differentiation and inducing T-cell exhaustion. In addition, PD-L1 on endothelial cells might promote plaque stability by reducing apoptosis and increasing expression of tight junction molecules. In the heart, IC downregulate the immune response to protect against cardiac injury by reducing T-cell activity and migration. Here, inhibition of IC could induce life-threatening T-cell-mediated-myocarditis. One proposed purpose behind lymphocyte infiltration is reaction to cardiac antigens, caused by decreased self-tolerance, and thereby increased autoimmunity because of IC inhibition. In addition, there are several reports of ICI-mediated cardiomyopathy with immunoglobulin G expression on cardiomyocytes, indicating an autoimmune response. IC are mostly known due to their cardiotoxicity. However, t his review compiles current knowledge on mechanisms behind IC function in cardiovascular disease with the aim of providing an overview of possible therapeutic targets in prevention or treatment of cardiovascular irAEs.

Immune Checkpoint Therapies and Atherosclerosis: Mechanisms and Clinical Implications: JACC State-of-the-Art Review

Immune checkpoint inhibitor therapy has revolutionized the treatment of advanced malignancies in recent years. Numerous reports have detailed the myriad of possible adverse inflammatory effects of immune checkpoint therapies, including within the cardiovascular system. However, these reports have been largely limited to myocarditis. The critical role of inflammation and adaptive immunity in atherosclerosis has been well characterized in preclinical studies, and several emerging clinical studies indicate a potential role of immune checkpoint targeting therapies in the development and exacerbation of atherosclerosis. In this review, we provide an overview of the role of T-cell immunity in atherogenesis and describe the molecular effects and clinical associations of both approved and investigational immune checkpoint therapy on atherosclerosis. We also highlight the role of cholesterol metabolism in oncogenesis and discuss the implications of these associations on future treatment and monitoring of atherosclerotic cardiovascular disease in the oncologic population receiving immune checkpoint therapy.

Antiatherogenic Effects of Quercetin in the THP-1 Macrophage Model In Vitro, With Insights Into Its Signaling Mechanisms Using In Silico Analysis

Background: Atherosclerosis (AS), a major risk factor for stroke and brain tissue destruction, is an inflammatory disease of the blood vessels, and the underlying pathology is inflammation mediated by various chemokines and cytokines. Quercetin, a natural flavonol, is reported to have both anti-inflammatory and antioxidant properties. As such, in the present study, we evaluated the antiatherogenic effects of quercetin in a human THP-1 cell line in vitro and also the signaling mechanisms using in silico analysis.

Materials and Methods: THP-1 macrophages exposed to different concentrations of quercetin (5–100 μM for 24 h) were tested for cytotoxicity. Real-time gene expression assay for intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) was carried out following treatment with quercetin at 15 and 30 μM for 24 h either in the absence or presence of interferon (IFN-γ) for 3 h to induce inflammation. Monocyte migration and cholesterol efflux were also assessed.

Results: Quercetin did not exert any cytotoxic effects on THP-1 cells at the various concentrations tested. The gene expression assay showed a significant decrease in ICAM-1 (by 3.05 and 2.70) and MCP-1 (by 22.71 and 27.03), respectively. Quercetin at 15 µM decreased THP-1 monocyte migration by 33% compared to the MCP-1-treated cells. It also increased cholesterol efflux significantly by1.64-fold and 1.60-fold either alone or in combination with IFN-γ, respectively. Ingenuity Pathway Analysis of the molecular interactions of quercetin identified canonical pathways directly related to lipid uptake and cholesterol efflux. Furthermore, CD36, SR-A, and LXR-α also demonstrated significant increases by 72.16-, 149.10-, and 29.68-fold, respectively.

Conclusion: Our results from both in vitro and in silico studies identified that quercetin inhibited the THP-1 monocyte migration, MCP-1, and ICAM-1 and increased cholesterol efflux probably mediated via the LXR/RXR signaling pathway. Therefore, quercetin will help prevent cell infiltration in atherosclerotic plaques and reduce the risk of stroke or brain destruction.

Vascular toxic effects of cancer therapies

Cancer therapies can lead to a broad spectrum of cardiovascular complications. Among these, cardiotoxicities remain of prime concern, but vascular toxicities have emerged as the second most common group. The range of cancer therapies with a vascular toxicity profile and the clinical spectrum of vascular toxic effects are quite broad. Historically, venous thromboembolism has received the greatest attention but, over the past decade, the arterial toxic effects, which can present as acute vasospasm, acute thrombosis and accelerated atherosclerosis, of cancer therapies have gained greater recognition. This Review focuses on these types of cancer therapy-related arterial toxicity, including their mechanisms, and provides an update on venous thromboembolism and pulmonary hypertension associated with cancer therapies. Recommendations for the screening, treatment and prevention of vascular toxic effects of cancer therapies are outlined in the context of available evidence and society guidelines and consensus statements. The shift towards greater awareness of the vascular toxic effects of cancer therapies has further unveiled the urgent needs in this area in terms of defining best clinical practices. Well-designed and well-conducted clinical studies and registries are needed to more precisely define the incidence rates, risk factors, primary and secondary modes of prevention, and best treatment modalities for vascular toxicities related to cancer therapies. These efforts should be complemented by preclinical studies to outline the pathophysiological concepts that can be translated into the clinic and to identify drugs with vascular toxicity potential even before their widespread clinical use.

The role of interferon-γ in cardiovascular disease: an update

PURPOSE

Cardiovascular disease (CVD) is the leading cause of death, globally, and its prevalence is only expected to rise due to the increasing incidence of co-morbidities such as obesity and diabetes. Medical treatment of CVD is directed primarily at slowing or reversing the underlying atherosclerotic process by managing circulating lipids with an emphasis on control of low-density lipoprotein (LDL) cholesterol. However, over the past several decades, there has been increasing recognition that chronic inflammation and immune system activation are important contributors to atherosclerosis. This shift in focus has led to the elucidation of the complex interplay between cholesterol and cellular secretion of cytokines involved in CVD pathogenesis. Of the vast array of cytokine promoting atherosclerosis, interferon (IFN)-γ is highly implicated and, therefore, of great interest.

METHODS

Literature review was performed to further understand the effect of IFN-γ on the development of atherosclerotic CVD.

RESULTS

IFN-γ, the sole member of the type II IFN family, is produced by T cells and macrophages, and has been found to induce production of other cytokines and to have multiple effects on all stages of atherogenesis. IFN-γ activates a variety of signaling pathways, most commonly the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, to induce oxidative stress, promote foam cell accumulation, stimulate smooth muscle cell proliferation and migration into the arterial intima, enhance platelet-derived growth factor expression, and destabilize plaque. These are just a few of the contributions of IFN-γ to the initiation and progression of atherosclerotic CVD.

CONCLUSION

Given the pivotal role of IFN-γ in the advancement of CVD, activation of its signaling pathways is being explored as a driver of atherosclerosis. Manipulation of this key cytokine may lead to novel therapeutic avenues for CVD prevention and treatment. A number of therapies are being explored with IFN-γ as the potential target.

Inflammation: A Novel Therapeutic Target/Direction in Atherosclerosis

Over the past two decades, the viewpoint of atherosclerosis has been replaced gradually by a lipid-driven, chronic, low-grade inflammatory disease of the arterial wall. Current treatment of atherosclerosis is focused on limiting its risk factors, such as hyperlipidemia or hypertension. However, treatment targeting the inflammatory nature of atherosclerosis is still very limited and deserves further attention to fight atherosclerosis successfully. Here, we review the current development of inflammation and atherosclerosis to discuss novel insights and potential targets in atherosclerosis, and to address drug discovery based on anti-inflammatory strategy in atherosclerotic disease.

Interferon-γ: Promising therapeutic target in atherosclerosis

Atherosclerosis is a chronic inflammatory disorder of the vasculature and is the primary cause of cardiovascular disease (CVD). CVD is currently the world’s leading cause of death and the numbers are predicted to rise further because of a global increase in risk factors such as diabetes and obesity. Current therapies such as statins have had a major impact in reducing mortality from CVD. However, there is a marked residual CVD risk in patients on statin therapy. It is therefore important to understand the molecular basis of this disease in detail and to develop alternative novel therapeutics. Interferon-γ (IFN-γ) is a pro-inflammatory cytokine that is often regarded as a master regulator of atherosclerosis development. IFN-γ is able to influence several key steps during atherosclerosis development, including pro-inflammatory gene expression, the recruitment of monocytes from the blood to the activated arterial endothelium and plaque stability. This central role of IFN-γ makes it a promising therapeutic target. The purpose of this editorial is to describe the key role IFN-γ plays during atherosclerosis development, as well as discuss potential strategies to target it therapeutically.

Targeting the adaptive immune system: new strategies in the treatment of atherosclerosis

Atherosclerosis is a lipid-driven chronic inflammatory disease of the arterial wall. Current treatment of atherosclerosis is focused on limiting its risk factors, such as hyperlipidemia or hypertension. However, treatments that target the inflammatory nature of atherosclerosis are still under development. Discovery of novel targets involved in the inflammation of the arterial wall creates opportunities to design new therapeutics that successfully modulate atherosclerosis. Here, we review drug targets that have proven to play pivotal roles in the adaptive immune system in atherosclerosis, and we discuss their potential as novel therapeutics.