Deficiency of extracellular vesicles miR-32 from bone marrow mesenchymal stem cells alleviates vascular calcification in type 2 diabetes by inhibiting endothelial ferroptosis

The development of vascular calcification (VC) in diabetes is closely related to the endothelial-to-mesenchymal transition (EndMT). We found that microRNA-32-5p (miR-32) was elevated in the plasma of calcification patients. However, it is unclear whether miR-32 mediates the function of bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) in type 2 diabetes (T2D) VC. BMSC-EVs were characterized by TEM, NTA, Western blotting, and confocal microscopy. Alizarin Red and ALP staining assessed the severity of VC. qRT-PCR and Western blotting evaluated the expression of BMP2, RUNX2, GPX4, SLC7A11, VE-cadherin, and N-cadherin, while immunofluorescence was used for detecting VE-cadherin and N-cadherin. In vivo validation was performed using miR-32 –/– and ApoE –/– mice. RNA sequencing (RNA-seq) and bioinformatics analysis was conducted to explore underlying mechanisms. We demonstrated that BMSC-EVs attenuate VC in endothelial cells (ECs) and inhibit EndMT. In vivo, histological analysis showed that treatment with BMSC-EVs significantly reduced the severity of VC associated with T2D. Notably, knockout of miR-32 further enhanced the inhibitory effect of BMSC-EVs on VC. Mechanistically, transcriptomic and functional analyses suggest that the protective effect of BMSC-EVs on VC is associated with regulation of the MAPK/FoxO signaling pathway, potentially mediated by modulation of ferroptosis. These findings demonstrate that BMSC-EVs attenuate T2D-associated VC, partially through miR-32-mediated suppression of EC ferroptosis.