Cell-specific and divergent roles of the CD40L-CD40 axis in atherosclerotic vascular disease

Abstract

Atherosclerosis is a major underlying cause of cardiovascular disease. Previous studies showed that inhibition of the co-stimulatory CD40 ligand (CD40L)-CD40 signaling axis profoundly attenuates atherosclerosis. As CD40L exerts multiple functions depending on the cell-cell interactions involved, we sought to investigate the function of the most relevant CD40L-expressing cell types in atherosclerosis: T cells and platelets. Atherosclerosis-prone mice with a CD40L-deficiency in CD4+ T cells display impaired Th1 polarization, as reflected by reduced interferon-γ production, and smaller atherosclerotic plaques containing fewer T-cells, smaller necrotic cores, an increased number of smooth muscle cells and thicker fibrous caps. Mice with a corresponding CD40-deficiency in CD11c+ dendritic cells phenocopy these findings, suggesting that the T cell-dendritic cell CD40L-CD40 axis is crucial in atherogenesis. Accordingly, sCD40L/sCD40 and interferon-γ concentrations in carotid plaques and plasma are positively correlated in patients with cerebrovascular disease. Platelet-specific deficiency of CD40L does not affect atherogenesis but ameliorates atherothrombosis. Our results establish divergent and cell-specific roles of CD40L-CD40 in atherosclerosis, which has implications for therapeutic strategies targeting this pathway.

Immuno-PET Imaging of Atherosclerotic Plaques with [89Zr]Zr-Anti-CD40 mAb—Proof of Concept

“…CD40 was our first choice as a proof of concept for detecting vulnerable lesions as CD40 expression is not limited to (activated) macrophages, but can be found on B cells, activated endothelial cells and smooth muscle cells, and repeated experiments in our own group have demonstrated the crucial role CD40 plays in plaque development [13,14,16,26]. The results of this study suggest that the [ 89 Zr]Zr-anti-CD40 mAb has successfully passed its initial preclinical validation phase for detecting CD40 atherosclerotic plaques using PET-CT imaging.…”

“…Both CD40 and CD40L are expressed in human atherosclerotic lesions [12], and showed increased expression when atherosclerosis progresses, with highest expression in vulnerable plaques. Inhibition of CD40L or CD40 signaling, either via genetic deficiency or antibody and small molecule mediated inhibition, strongly decreased atherosclerotic plaque burden and induced a stable atherosclerotic plaque phenotype, showing a direct effect of CD40 in inducing plaque vulnerability [12][13][14]. Therefore, visualizing CD40 by PET in atherosclerosis has the potential to predict plaque vulnerability.…”

Immune Mechanisms of Plaque Instability

“…Enhanced CD40L gene expression and other proinflammatory cues such as IFN-γ, TNF-α, and IL-1 upregulate its major ligand CD40 on lesional APCs and smooth muscle cells (SMCs) ( 152 ). Plaques from hypercholesteremic atherosclerotic mice treated with an anti-CD40L antibody are more matrix-rich and more stable and contain less macrophages and T-cells ( 153 – 155 ), mechanistically explained through decreased VCAM-1 expression ( 154 ) and enhanced TGF-β signaling ( 155 ); specifically, the binding of T-cell-expressed CD40L to surface-CD40 in DCs enhanced T H 1 polarization and increased T H 1-associated IFN-γ production ( 156 ). In a CD4 + T-cell-specific conditional CD40L-KO model, plaques were less proinflammatory and had smaller NCs and thicker caps ( 156 ).…”

“…Plaques from hypercholesteremic atherosclerotic mice treated with an anti-CD40L antibody are more matrix-rich and more stable and contain less macrophages and T-cells ( 153 – 155 ), mechanistically explained through decreased VCAM-1 expression ( 154 ) and enhanced TGF-β signaling ( 155 ); specifically, the binding of T-cell-expressed CD40L to surface-CD40 in DCs enhanced T H 1 polarization and increased T H 1-associated IFN-γ production ( 156 ). In a CD4 + T-cell-specific conditional CD40L-KO model, plaques were less proinflammatory and had smaller NCs and thicker caps ( 156 ). Monocyte-to-macrophage differentiation, T-cell-CD40L interaction with macrophage-CD40 ( 157 ) and a proinflammatory cytokine-milieu all induce macrophages to overproduce a broad spectrum of highly destructive MMPs ( 121 ), which degrade ECM and promote thinning of the fibrous cap.…”

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

“…Therefore, a more targeted therapeutic strategy could lie in the development of cell type specific antibodies or targeted nanopharmaceuticals to avoid negative side effects of a complete or global CD40/CD40L blocking ( Duivenvoorden et al, 2019 ; van de Vyver et al, 2021 ). Several in vivo studies regarding cell type specific deficiency of CD40/CD40L are still ongoing with promising data ( Gissler et al, 2021b ; Lacy et al, 2021 ; Bosmans et al, 2022 ). For example, endothelial-cell specific deletion of CD40 in ApoE −/− mice leads to a more stable plaque phenotype and to reduced leukocyte adhesion compared to control mice when subjected to a high-fat diet.…”