Work

Endothelial senescence impairs efferocytosis and alters macrophage responses: insights into APP-CD74 signaling

Year: 2026

Type: article

Abstract: Background Endothelial cell senescence contributes to vascular aging and chronic inflammation, yet its impact on endothelial–macrophage interactions remains poorly understood. Here, we combined functional assays, global proteomics, 3D co-culture spheroid models, and single-cell transcriptomics to elucidate how senescent endothelial cells modulate macrophage phenotype and intercellular communication. Methods Replicative senescence in human umbilical vein endothelial cells (HUVEC) was achieved via their extended passages. Human monocyte-derived macrophages (MDM) were obtained via differentiation of peripheral blood mononuclear cells. Results Senescent endothelial cells (sEC) exhibited classical morphological and molecular markers of senescence. In addition, sEC underwent apoptosis less frequently than control endothelial cells (cEC) under detachment stress. Apoptotic sEC retained higher levels of the “don’t-eat-me” signal CD47 and were cleared less efficiently by human MDMs, indicating increased resistance to efferocytosis. Proteomic profiling revealed more than 1,000 proteins differentially expressed in sECs, with enrichment of pathways related to lysosomal function, immune activation, antigen presentation, and TNF signaling. In 3D EC–macrophage spheroids, single-cell RNA sequencing identified heterogeneous EC populations (KLF2⁺, SERPINE1⁺, and MEOX2⁺) and three macrophage subsets (FOLR2⁺, CHI3L1⁺, and MKI67⁺). KEGG pathway analysis indicated consistent enrichment of the Phagosome pathway across macrophage populations, with additional changes in inflammatory and antigen-processing programs in FOLR2⁺ and CHI3L1⁺ macrophages. Ligand–receptor analysis using CellChat highlighted APP–CD74 signaling as a key senescence-enhanced communication axis. sECs showed increased APP expression and stronger predicted signaling to CD74-expressing FOLR2⁺ and MKI67⁺ macrophage subsets, whereas hypoxia-adapted CHI3L1⁺ macrophages exhibited reduced CD74 levels. Functional validation in a paracrine transwell model did not show significant changes in macrophage CD74 abundance following APP knockdown in endothelial cells, although recombinant APP770 reduced IL-10 expression and secretion by macrophages. Conclusions Together, these findings reveal that endothelial senescence impairs efferocytic clearance and alters macrophage responses, potentially contributing to immune dysregulation associated with vascular aging.

Source: Cell Communication and Signaling

DOI: 10.1186/s12964-026-03275-3