Naoxintong capsule decreases circulating exosomes of miR-382-5p to protect LPS-induced vascular endothelial cell injury by targeting STC1 in vitro.

BACKGROUND: Cardiovascular and cerebrovascular diseases, major health threats in aging populations, involve vascular endothelial injury as a key pathological factor. Circulating exosomes, a type of extracellular vesicles involved in substance transport and signal transduction, serve as regulatory mediators in vascular diseases. Naoxintong Capsule (NXT), a traditional Chinese medicine with 3 decades of clinical application, protects vascular diseases via multifaceted mechanisms, yet its circulating exosome-mediated endothelial protection remains unclear. METHODS: Circulating exosomes were isolated from NXT-treated (NXT-Exo) and saline-treated (Ctl-Exo) SD rats. The effect of NXT-Exo and Ctl-Exo on lipopolysaccharide (LPS) induced human microvascular endothelial cells (HMEC-1) injury was studied using molecular biology experiments. RNA-seq and miRNA-omics analysis were performed to elucidate the mechanisms of NXT-Exo. Western blot and enzyme linked immunosorbent assay (ELISA) were used to validate the therapeutic target of NXT-Exo. RESULTS: NXT-Exo attenuated LPS-induced HMEC-1 injury by suppressing apoptosis, inflammation, oxidative stress, and endothelial dysfunction, while Ctl-Exo showed no effect. RNA-seq revealed the TLR4/TRIF/NF-κB signaling pathway might play a crucial role in NXT-Exo's effect. miRNA-omics suggested miR-382-5p as a pivotal mediator, and ELISA confirmed that its downregulation contributes to the protective effect of NXT-Exo. Integrated analysis indicated Stanniocalcin-1 (STC1) may be a miR-382-5p target. Western blot results showed that STC1 silencing aggravated the pro-injury effects of miR-382-5p. CONCLUSION: Our findings elucidated that NXT protected HMEC-1 from injury and dysfunction by downregulating miR-382-5p in circulating exosomes, potentially via targeting STC1 and inhibiting the TLR4/TRIF/NF-κB pathway.