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

Abstract

Aims CD40 and its ligand, CD40L, play a critical role in driving atherosclerotic plaque development. Disrupted CD40-signaling reduces experimental atherosclerosis and induces a favourable stable plaque phenotype. We recently showed that small molecule-based inhibition of CD40-TNF Receptor Associated Factor-6 interactions attenuates atherosclerosis in hyperlipidaemic mice via macrophage-driven mechanisms. The present study aims to detail the function of myeloid CD40 in atherosclerosis using myeloid-specific CD40-deficient mice. Method and Results Cd40flox/flox and LysM-cre Cd40flox/flox mice on an Apoe-/- background were generated (CD40wt and CD40mac-/-, respectively). Atherosclerotic lesion size, as well as plaque macrophage content, were reduced in CD40mac-/- compared to CD40wt mice and their plaques displayed a reduction in necrotic core size. Transcriptomics analysis of the CD40mac-/- atherosclerotic aorta revealed downregulated pathways of immune pathways and inflammatory responses. Loss of CD40 in macrophages changed the representation of aortic macrophage subsets. Mass cytometry analysis revealed a higher content of a subset of alternative or resident-like CD206 + CD209b- macrophages in the atherosclerotic aorta of CD40mac-/- compared to CD40wt mice. RNA-sequencing of bone marrow-derived macrophages (BMDMs) of CD40mac-/- mice demonstrated upregulation of genes associated with alternatively activated macrophages (including Folr2, Thbs1, Sdc1 and Tns1). Conclusions We here show that absence of CD40 signalling in myeloid cells reduces atherosclerosis and limits systemic inflammation by preventing a shift in macrophage polarization towards pro-inflammatory states. Our study confirms the merit of macrophage-targeted inhibition of CD40 as a valuable therapeutic strategy to combat atherosclerosis.

Vulnerable Atherosclerotic Plaque: Is There a Molecular Signature?

“…Lack of expression of CD40 in the macrophages resulted in a reduced atherosclerotic plaque and necrotic core and a decreased macrophage content by shifting macrophage activation towards a more antiinflammatory profile. On the contrary, oxidized LDL stimulated CD40 expression and promoted an active immune and inflammatory response [ 84 ]. CD40 found on platelets was involved in platelet-leukocyte aggregation and the release of chemokine ligand 4, but did not affect platelet aggregation [ 85 ].…”

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.…”

“…This phenotype is probably caused by alternative macrophage activation in atherosclerotic aortas which express a more anti-inflammatory profile than CD40-containing macrophages as well as the prevention of CD40 macrophage polarization towards pro-inflammatory states. Taken together, mice with CD40-deficient macrophages show less inflammation in the atherosclerotic aorta ( Bosmans et al, 2022 ). The cell type specific deletion of CD40 is an emerging field, which could lead to a better understanding of the involvement of CD40-CD40L signaling in inflammation and the progression of atherosclerosis.…”

Adipocytes control hematopoiesis and inflammation through CD40 signaling

“…13 Furthermore, T-cell specific CD40L-deficiency decreased atherosclerosis by affecting Th1 polarization and IFNγ production 10 , but did not affect weight gain or insulin resistance (IR) in mice with diet-induced obesity (DIO). 14 The CD40 -/mice showed reduced atherosclerosis 15 , as do macrophage 17 , and dendritic cell 10 specific CD40-deficient mice. However, full body CD40deficient mice displayed aggravated IR and severe AT inflammation during DIO 16,19 , whereas deficiency of macrophage CD40 only causes minor obesity related metabolic dysfunction.…”

“…Deletion of the co-stimulatory immune checkpoints CD40 or CD40L has shown different effects on haematopoiesis, obesity, the metabolic syndrome, and atherosclerosis. 4,[11][12][13][14][15][16][17][18][19] CD40L -/mice that were subjected to an obesogenic diet exhibited less weight gain, improved insulin resistance, and diminished AT inflammation. 13 Furthermore, T-cell specific CD40L-deficiency decreased atherosclerosis by affecting Th1 polarization and IFNγ production 10 , but did not affect weight gain or insulin resistance (IR) in mice with diet-induced obesity (DIO).…”