Abstract: TH-OR056
Tubular Extracellular Vesicles Mediate Vascular Calcification in CKD via Complement C3
Session Information
- New Developments in Bones, Stones, and Mineral Metabolism
November 06, 2025 | Location: Room 370A, Convention Center
Abstract Time: 04:40 PM - 04:50 PM
Category: Bone and Mineral Metabolism
- 501 Bone and Mineral Metabolism: Basic
Authors
- Zhang, Yu-xia, Southeast University School of Medicine, Nanjing, Jiangsu, China
- Tang, Tao-Tao, Southeast University School of Medicine, Nanjing, Jiangsu, China
- Tang, Ri-ning, Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital, Nanjing, Jiangsu, China
- Liu, Bi-Cheng, Southeast University School of Medicine, Nanjing, Jiangsu, China
Background
Chronic kidney disease (CKD) often leads to vascular calcification (VC), a severe complication recognized as a major cardiovascular risk factor. The molecular mechanisms underlying CKD-VC remain unclear. This study investigates the role of tubular extracellular vesicles (EVs) in mediating CKD-VC through the transport of complement C3.
Methods
A CKD-VC mouse model was established using adenine combined with a high-phosphate diet. VC was assessed via VonKossa staining in CKD-VC mice treated with GW4869, renal EVs, or C3aR inhibitor. Tubular EV trafficking was visualized in aorta using immunofluorescence in tubular EV-tracing mice(Slc34a1 Cre/+;CD63-PAGFP fl/+ mice). Complement activation and localization in renal tubules were evaluated in CKD-VC mice via WB, PCR, and immunofluorescence. EVs isolated from renal tissues and plasma were analyzed for C3 and tubular markers by WB and ELISA. Single-molecule imaging and nanoflow cytometry determined the C3 distribution in renal and plasma EVs. Tubular-specific C3 knockdown mice was achieved using adeno-associated virus to assess VC. In vitro, VSMC treated with high-phosphate were treated with tubular EVs or the C3aR inhibitor, and then osteogenic differentiation markers and C3aR were analyzed by PCR and WB, with calcification visualized via Alizarin Red staining. Plasma EVs from 30 CKD patients with VC and healthy controls were assayed for C3.
Results
Renal EVs exacerbated VC in CKD mice, while GW4869 attenuated calcification. Proteomics revealed high C3 expression in renal EVs. CKD-VC mice exhibited tubular complement activation and EV-mediated C3 secretion into circulation. Plasma EVs from CKD showed significantly elevated C3 levels compared to controls. Immunofluorescence confirmed uptake of tubular EVs by calcified aorta. In vitro, tubular EVs enhanced VSMC osteogenic differentiation and upregulated C3aR, mimicking C3a effects, while C3aR inhibition reversed these outcomes. Tubular C3 knockdown in vivo reduced VC severity. Clinically, plasma EV C3 levels correlated positively with abdominal aortic calcification scores in CKD-VC patients.
Conclusion
This study demonstrates that tubule-derived EVs mediate vascular smooth muscle osteogenic transdifferentiation and CKD-VC via C3 transport. Targeting EV-C3 signaling may represent a novel therapeutic strategy for CKD-VC.