Lutgens, Esther

ABSTRACT The advent of immunological therapies has revolutionized the treatment of solid and haematological cancers over the last decade. Licensed therapies which activate the immune system to target cancer cells can be broadly divided into two classes. The first class are antibodies that inhibit immune checkpoint signalling, known as immune checkpoint inhibitors (ICIs). The second class are cell-based immune therapies including chimeric antigen receptor T lymphocyte (CAR-T) cell therapies, natural killer (NK) cell therapies, and tumour infiltrating lymphocyte (TIL) therapies. The clinical efficacy of all these treatments generally outweighs the risks, but there is a high rate of immune-related adverse events (irAEs), which are often unpredictable in timing with clinical sequalae ranging from mild (e.g. rash) to severe or even fatal (e.g. myocarditis, cytokine release syndrome) and reversible to permanent (e.g. endocrinopathies).The mechanisms underpinning irAE pathology vary across different irAE complications and syndromes, reflecting the broad clinical phenotypes observed and the variability of different individual immune responses, and are poorly understood overall. Immune-related cardiovascular toxicities have emerged, and our understanding has evolved from focussing initially on rare but fatal ICI-related myocarditis with cardiogenic shock to more common complications including less severe ICI-related myocarditis, pericarditis, arrhythmias, including conduction system disease and heart block, non-inflammatory heart failure, takotsubo syndrome and coronary artery disease. In this scientific statement on the cardiovascular toxicities of immune therapies for cancer, we summarize the pathophysiology, epidemiology, diagnosis, and management of ICI, CAR-T, NK, and TIL therapies. We also highlight gaps in the literature and where future research should focus.

The CD40-CD40L co-stimulatory dyad has been identified as critical player in atherosclerosis. Our previous work has shown that CD40 and CD40L have cell divergent effects on atherosclerosis. Deficiency of the CD40-CD40L dendritic cell-T cell axis decreased atherosclerosis via reducing T helper 1 responses, whereas deficiency of macrophages CD40 reduced atherosclerosis by enhancing efferocytosis and reducing necrotic core content. CD40 is highly expressed on B cells and interacts with CD40L on T cells to induce antibody production and T follicular helper cell responses. We therefore hypothesize that deletion of CD40 will reduce atherosclerosis. We aim to unravel the role of B cell CD40 in atherosclerosis. CD40 expression on B cell subsets was determined on peripheral blood mononuclear cells of patients and correlated with severity of coronary artery disease (CAD). Atherosclerosis was analyzed in CD19 Cre CD40 flfl ApoE -/- mice that were fed an atherogenic diet for 14 weeks. Patients with CAD showed a decrease in CD40 on their putative B1 cells, which was associated with increased plaque burden and decreased plaque fibrosis as detected by coronary intravascular ultrasound. Depletion of CD40 on B cells in ApoE -/- mice resulted in a decreased germinal center formation and inadequate IgM production as expected. However, in line with our patient data, absence of B cell-CD40 increased atherosclerosis. This was caused by a reduction in B1 cells and consequently a reduction in atheroprotective anti-oxidation specific epitope (OSE) IgMs. Transfer of CD40-competent B1b cells in B cell-CD40-deficient mice restored anti-OSE IgM levels and prevented the increase in atherosclerosis. CD40-deficient B1b cells have an altered mTOR signaling pathway, impaired mitochondrial function, excessive uptake of lipids, increased cellular stress and accelerated cell death. Data indicate that CD40-deficiency promotes phosphorylation of RAPTOR and protein kinase B (AKT). We have identified a novel function of CD40 on B1b cells. B1b cell-CD40 exerts an anti-atherogenic role by regulating B1b cell metabolic homeostasis via mTOR pathway. Further mechanistic insights into how CD40 mounts adequate atheroprotective anti-OSE IgM production are currently being investigated.

Background Atherosclerosis is highly prevalent in people with chronic kidney disease (CKD), including those receiving peritoneal dialysis (PD). Although it is lifesaving, PD induces profound systemic inflammation, which may aggravate atherosclerosis. Therefore, the hypothesis is that this PD‐induced inflammation aggravates atherosclerosis via immune cell activation. Methods and Results ApoE −/− mice were subjected to a 5/6 nephrectomy to induce CKD. Three weeks later, mice were fed a high‐cholesterol diet. Half of the nephrectomized mice then received daily peritoneal infusions of 3.86% Physioneal for 67 further days (CKD+PD) until the end of the experiment, and were compared with mice without CKD. Sham operated and PD‐only mice were additional controls. CKD+PD mice displayed more severe atherosclerotic disease than control mice. Plaque area increased, and plaques were more advanced with a vulnerable phenotype typified by decreased collagen content and decreased fibrous cap thickness. Increased CD3 + T‐cell numbers were present in plaques and perivascular adipose tissue of CKD and CKD+PD mice. Plaques of CKD+PD mice contained more iNOS + immune cells. Spleens of CKD+PD mice showed more CD4 + central memory, terminally differentiated type 1 T‐helper (Th1), Th17, and CX3C motif chemokine receptor 1 + (CX3CR1) CD4 + T‐cells with less regulatory and effector T‐cells. Conclusions PD‐fluid exposure in uremic mice potentiates systemic and vascular T‐cell‐driven inflammation and aggravates atherosclerosis. PD polarized CD4 + T‐cells toward an inflammatory Th1/Th17 phenotype, and increased CX3CR1 + CD4 + T‐cells, which are associated with vascular homing in CKD‐associated atherosclerosis. Targeting CD4 + T‐cell activation and CX3CR1 + polarization has the potential to attenuate atherosclerosis in PD patients.

The single-cell platform mass cytometry (CyTOF) enables detection of significant changes in one million of renal cells, especially in subsets of immune cells in ischemic human kidneys distal to renal artery stenosis (RAS). We found that pro-repair cell types such as scattered tubular-progenitor-like cells, aged neutrophils, and regulatory B cells show a compensatory increase in RAS. Immune cell phenotype changes may reflect ongoing inflammation and impaired immune defense capability in the kidneys.

Abstract Introduction Immune checkpoint (IC) targeting is an attractive way to combat atherosclerosis, since ICs regulate the immune response by activating or inhibiting inflammatory pathways. We have shown that ICs exert cell-divergent functions and that cell-specific IC-based treatments can limit immune-related side effects. To design tailored IC-based immunotherapies for atherosclerosis, a detailed single-cell atlas of IC expression during atherogenesis is required. Purpose To obtain cell-type- and atherosclerosis-stage-specific expression profiles of ICs and assess the transcriptome of IC+ cells during atherosclerosis. Methods ApoE-/- mice were fed normal chow diet (NCD) for 10, 20 or 30 weeks, or high-cholesterol diet (HCD) for 6, 10, 14 (study 1) or 20 weeks (study 2). Using mass-cytometry by time of flight (CyTOF), we assessed the cell-type-specific aortic expression of ICs during atheroprogression (study 1). Using cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq), we assessed the transcriptome of aortic IC+ and IC- cells (study 2). Results Using CyTOF, we identified 21 immune cell clusters, including T and B cells, Ly6C- and Ly6C+ monocytes and macrophage (mφ) subsets. On T cell subsets, IC expression remained relatively constant in early plaques independent of the type of diet, apart from an increase in CD40-CD40L and decrease in CD28 and PD-L1 in HCD-fed mice. In advanced plaques from NCD-fed mice, most T cell subsets showed increased PD-L1, GITRL and CD27, while in HCD-fed mice, CD40L was decreased and PD-L1, PD-L2, CD27, CD86-CD28 and GITR-GITRL were induced on these T cell subsets. On myeloid cells, IC expression changed during early atherogenesis. Specifically, in NCD-fed mice, CD11c+MHCII+ mφ upregulated CD40 and PD-L1 and downregulated CD27 and PD-L2, while dendritic cells increased GITR and decreased PD-L2. Additional ICs, such as GITRL, CD40L and CD86-CD28, were induced in advanced plaques from NCD-fed mice. In HCD-fed mice, numerous ICs, i.e. CD40-CD40L, GITR-GITRL, CD86-CD28 and PD-L2, were increased in myeloid subsets in both early and advanced plaques. Using CITE-Seq, we further studied ICs that were strongly regulated during atherogenesis, e.g. GITR. Gene Ontology enrichment analysis of GITR+ and GITR- cells within the myeloid and T cell subsets identified the regulation of various pathways: When compared to their GITR- counterparts, both CD25- and CD25+ CD4+GITR+ T cell subsets showed upregulated pathways of death receptor activity, while CD25+ cells also showed induction of pathways involved in transmembrane lipid transporter activity. In mφ, GITR+ mφ showed upregulated pathways of cell adhesion and cytokine activity compared to GITR- mφ. Conclusion We have identified the expression pattern of numerous ICs on aortic immune cell subsets at various atherosclerosis stages. These data will pave the way towards the development of selective IC-based therapies to combat atherosclerosis.

Abstract Background The co-stimulatory CD40–CD40 ligand axis is central in atherogenesis. Upon activation, CD40 recruits tumor necrosis factor receptor-associated factors (TRAFs) to induce downstream signaling. Murine studies with mutated CD40-TRAF binding sites in macrophages have shown that the CD40-TRAF6, rather than CD40-TRAF2/3/5, axis is crucial for atherosclerosis. We thus synthesized the small molecule inhibitor TRAF-STOP 6877002, that selectively blocks CD40-TRAF6 signaling. 6877002 successfully reduced the onset and development of atherosclerosis by reducing monocyte recruitment and macrophage activation in ApoE-/- mice without having immunosuppressive side effects. Purpose To assess whether 6877002 is a suitable candidate to pass the translational pipeline towards a clinical application. Methods Elaborate in vitro and in vivo assays evaluating the pharmacological properties and potential toxicity of 6877002. Results Together with Cyprotex, we performed in vitro assays examining the ADME profile of 6877002. In an intestinal permeability assay, 6877002 had low to moderate resorption with no significant efflux, suggesting it is not a substrate for the efflux transporters Pgp/BCRP or MRP2. A plasma protein binding assay showed very low unbound 6877002 fractions, indicating that it is highly bound to plasma proteins. The potential to inhibit cytochrome P450 enzymes was assessed using human liver microsomes in the presence of enzyme-specific probe substrates. While 6877002 inhibited CYP1A2 (IC50=4.01 µM), no potential for inhibiting other CYP isoforms was detected, suggesting low drug-drug interaction potential. To screen for putative cardiovascular risks, hERG ion channel inhibition was assessed and no IC50 could be determined. Hepatic clearance was rapid in mice, rats and dogs, while minipig and human hepatocytes had lower intrinsic clearance. Together with Aptuit, we developed suitable formulations for oral and i.v. administration. In vivo pharmacokinetics studies in rats showed low bioavailability (8.43%) and rapid clearance of orally administered 6877002 compared to i.v. injected 6877002, likely – and in line with our in vitro data – due to fast first-past effect in mouse hepatocytes and uptake by macrophages. To explain the high efficacy of 6877002 despite its rapid metabolism, we assessed whether 6877002 has active metabolites that bind the CD40-TRAF6 pocket and performed an LC-MS/MS-based metabolite profiling. We detected 17 metabolites. Further MD simulations confirmed that Metabolite (M)4, the most abundant metabolite, binds the CD40-TRAF6 pocket, reflected by the highest binding mode (-19.6; defined as Binding Free Energy derived from 40-50 ns of MD run as compared to -16.5 for 6877002). Similar to 6877002, M4 reduced atherosclerosis by 54% in Western diet-fed ApoE-/- mice, indicative of M4 being an active metabolite. Conclusion CD40-TRAF6 inhibitors are an attractive strategy to combat atherosclerosis with high translational potential.

Abstract Background Atherosclerosis is a chronic inflammatory disease, characterized by the formation of luminal plaques in arteries. Atheroprogression is accompanied by strong immune activation, during which T cells play a pivotal role. Genes driving T-cell activation are regulated by the polycomb repressive complex 2(PRC2), whose major component is the Enhancer of Zeste Homolog 2(EZH2), responsible for the methylation of Histone 3 Lysine 27(H3K27me3) epigenetic mark. Purpose We hypothesize that EZH2 mediates T-cell activation and modulates T-helper (Th) cell polarization, thus atherogenesis. Methods To study the effect of EZH2 in atherosclerosis, we backcrossed mice with Ezh2 flanked by loxP-sites sensitive to Cre-mediated inactivation in T cells to apolipoprotein E (Apoe-/-)mice and fed a high cholesterol diet to have hyperlipidemic Ezh2fl/flCd4CreApoe-/-mice and controls. Atherosclerotic plaque progression and immune cell phenotyping were assessed by histology, flow cytometry (FC), gene and protein expression analysis and single cell (sc)RNA-sequencing (Seq) as well as by functional in vitro assays. Results T cell-specific EZH2 deficiency resulted in a significant reduction in H3K27me3 in T-cells. Female Ezh2fl/flCd4Cre mice developed 34% less atherosclerotic plaques in the aortic root compared to wildtype (WT) littermates. FC analysis of spleen and lymph nodes of Ezh2fl/flCd4Cre mice revealed a shift from naive to effector CD4+ T cells, and the majority were Th2 cells (p<0.0001). Accordingly, plasma levels of lL4 and aortic IL4 transcripts were increased in Ezh2fl/flCd4Cre mice(p=0.05 and p=0.0079, respectively). Functional analysis revealed that splenic CD4+ T cells from Ezh2fl/flCd4Cre mice showed decreased migratory capacity towards the chemokines CXCL10, CCL17, CCL22, CCL19. To unravel mechanisms driving the type 2 immune response, bulk RNA-Seq of CD4+ T cells and scRNA-Seq of splenic CD3+ T cells from Ezh2fl/flCd4Cre and WT mice revealed that CD4+ T cell EZH2 deficiency caused upregulation of promyelocytic leukemia zinc finger (Plzf), a transcription factor of NKT cells of the NKT2 subtype, characterized by high IL4 production. Via FC we confirmed the increase in splenic NKT cells in Ezh2fl/flCd4Cre mice. Likewise, Plzf aortic mRNA levels were also significantly increased(p=0.002). To exploit the translational potential of T cell-specific EZH2 targeting, we treated Jurkat T cells with EZH2 inhibitors, the FDA-approved drug Tazemetostat and GSK126. Corroborating our in vivo data, EZH2 inhibitor-treated cells showed decreased H3K27me3 and 70% reduced migration towards the chemokine CXCL12. Conclusions Our study demonstrates that CD4+ T-cell specific EZH2 deficiency impairs T cell-migration and skews the immune response towards a type 2 response, resulting in protection against atherosclerosis. We aim at investigating whether the epigenetic mark H3K27me3 in T cells may be a promising therapeutic target for future cardiovascular immunotherapies.

Abstract Cardiovascular disease is the leading cause of death in women and men globally, with most due to atherosclerotic cardiovascular disease (ASCVD). Despite progress during the last 30 years, ASCVD mortality is now increasing, with the fastest relative increase in middle-aged women. Missed or delayed diagnosis and undertreatment do not fully explain this burden of disease. Sex-specific factors, such as hypertensive disorders of pregnancy, premature menopause (especially primary ovarian insufficiency), and polycystic ovary syndrome are also relevant, with good evidence that these are associated with greater cardiovascular risk. This position statement from the European Atherosclerosis Society focuses on these factors, as well as sex-specific effects on lipids, including lipoprotein(a), over the life course in women which impact ASCVD risk. Women are also disproportionately impacted (in relative terms) by diabetes, chronic kidney disease, and auto-immune inflammatory disease. All these effects are compounded by sociocultural components related to gender. This panel stresses the need to identify and treat modifiable cardiovascular risk factors earlier in women, especially for those at risk due to sex-specific conditions, to reduce the unacceptably high burden of ASCVD in women.

Abstract Background and Aims Inflammation is an established contributor to accelerated atherosclerosis, which is highly prevalent in people with chronic kidney disease (CKD) and even more so in those treated with peritoneal dialysis (PD). We therefore hypothesised that PD-induced systemic inflammation is essential in the development of atherosclerosis. To study this we developed a novel mouse model of CKD and PD accelerated atherosclerosis. Method We performed a 5/6ths nephrectomy in ApoE deficient “black 6” mice, fed these mice a high-cholesterol diet (HCD), and intraperitoneally administered 3.86% Physioneal daily for 67 days. There were three groups of mice: control (HCD-only), CKD+HCD, and CKD+HCD+PD, with relevant shams. Tissues were harvested twelve weeks after the nephrectomy. Assessments of residual kidney function, atherosclerotic plaque pathology and immunology, and systemic immune responses were performed. Results Atherosclerotic plaque size in the aortic arch was larger in the PD group compared to the control, increasing from 83,779 μm2 ±18,430 to 109,973 μm2 ±25,602 (p = 0.0349), whilst plaque size was unchanged in the CKD group. In contrast, both the CKD and PD groups displayed altered plaque stability. There was less collagen in the plaque vs control, decreasing from 43.54% ±10.65 to 29.71% ±9.43 and 29.73% ±10.18 respectively. Additionally, fibrous cap thickness decreased in both groups vs control. The plaques from only the PD group showed infiltration by T-cells compared to control, with no changes in macrophage content in either the CKD or PD group. In the spleen in the CKD and PD groups, naïve CD4 cells increased and effector CD4 cells decreased compared to control, with the latter change also occurring in the circulation. Central memory CD4 cells, terminally differentiated Th1 cells, Th17 cells, and ‘vascular homing’ cells all increased in the PD group compared to control mice. These homing cells also increased in circulation. The PD group showed decreases in the spleen of regulatory T-cells, effector Th1 cells, and effector CD8 cells. Notably, all of these changes were absent from the mesenteric lymph node. There was a large drop in monocytes in the spleen and a loss of immature and mature dendritic cells in the PD group. Conclusion Combining CKD, a high-cholesterol diet, and exposure to PD fluids in ApoE−/-mice successfully generated a new model for cardiovascular disease in human PD patients. This new model is in a widespread and well-understood mouse line representative of human atherosclerosis. Here we demonstrate the pronounced effects of CKD and PD on the innate and adaptive immune response which increases atherosclerotic burden and leads to larger more vulnerable plaques