Abstract Body: BACKGROUND: Atherosclerosis is driven by endothelial dysfunction, vascular inflammation, and endothelial-to-mesenchymal transition (EndMT), which contribute to plaque progression and instability. We previously identified angiopoietin-like protein 4 (ANGPTL4) as an endothelial-protective factor that suppresses inflammatory and TGF-β–driven EndMT through restoration of KLF2 signaling, thereby preserving vascular integrity in experimental models and human atherosclerotic lesions. However, human-relevant platforms that recapitulate immune–vascular interactions during atherosclerosis remain limited.
METHODS: We previously investigated the endothelial-protective effects of ANGPTL4 using murine atherosclerosis models, primary human endothelial cells, iPSC-derived endothelial cells, and patient-derived samples. To extend these findings, we are developing a human iPSC-derived atheroid platform by integrating vascular spheroids composed of endothelial cells, smooth muscle cells, and cardiac fibroblasts with iPSC-derived monocytes under inflammatory stimulation induced by TNF-α and oxidized LDL.
RESULTS: ANGPTL4 suppressed endothelial inflammation and inhibited TGF-β–Smad2–mediated EndMT through restoration of KLF2 signaling, preserving endothelial identity across experimental systems. To extend these findings in a human-relevant context, we established an iPSC-derived atheroid platform integrating vascular spheroids with iPSC-derived monocytes under inflammatory stimulation. This model exhibited early endothelial activation characterized by reduced CD31 and increased VCAM1 expression. It supported monocyte recruitment and formation of lipid-laden macrophage-like cells marked by BODIPY and CD68 staining. Smooth muscle cells displayed decreased SM22α expression, suggesting a contractile-to-synthetic phenotypic shift, together with increased COL1A1 and fibronectin deposition. Importantly, these pathological features developed without significant apoptosis, indicating disease-relevant stress rather than cytotoxicity.
CONCLUSIONS: Together, our previous findings establish ANGPTL4 as a key regulator of endothelial homeostasis in atherosclerosis. The development of a human iPSC-derived atheroid platform is expected to recapitulate the cellular and inflammatory microenvironment of human atherosclerotic lesions and provide a human-relevant system to investigate immune–vascular interactions and endothelial-protective mechanisms during disease progression.