Our previous study showed that chronic exposure to caffeine sodium benzoate (CSB) can cause endothelial cell dysfunction, but the specific mechanism is unclear. Endothelial progenitor cells (EPCs), as precursors of endothelial cells, can differentiate into vascular endothelial cells and assist in blood vessel repair. This study aimed to investigate the potential impact of CSB on EPC function. CSB containing serum (CSB-CS) were obtained from patients receiving long-term CSB abuse. RAW264. 7 macrophages were treated with different concentrations of CSB-CS, and the resulting conditioned medium (CSB-CSCM) was applied to EPCs to assess its effects. CSB-CS significantly induced M1 polarization of RAW264. 7 macrophages. Furthermore, CSB-CSCM remarkably led to endothelial dysfunction in EPCs, as evidenced by inhibited angiogenesis, increased cell senescence, and elevated levels of the dysfunction markers ET-1 and VCAM-1. Concurrently, CSB-CSCM also triggered mitochondrial impairment in EPCs, characterized by decreased mitochondrial membrane potential, reduced mitochondrial fusion and increased fission. Notably, these adverse effects on endothelial and mitochondrial function were partially reversed by MASM7, an activator of mitochondrial fusion. Additionally, CSB-CSCM remarkably reduced the levels of the mitochondrial fusion protein OPA1 in EPC. Mechanistically, let-7a-5p, which targets OPA1 mitochondrial dynamin like GTPase (OPA1), was upregulated by CSB-CSCM, leading to OPA1 suppression and subsequent mitochondrial and endothelial dysfunction. Collectively, pro-inflammatory macrophages induced by CSB-CS may contribute to EPC dysfunction by impairing mitochondrial function via the let-7a-5p/OPA1 pathway. These findings could provide a foundation for future treatments aimed at addressing endothelial dysfunction caused by CSB.
Yu et al. (Thu,) studied this question.