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

## TL;DR

Naoxintong Capsule protects blood vessel cells from injury by reducing harmful exosomes and targeting specific molecules.

## Contribution

The study reveals a novel mechanism by which Naoxintong Capsule protects endothelial cells via miR-382-5p and STC1.

## Key findings

- NXT-Exo reduced LPS-induced endothelial injury by suppressing apoptosis and inflammation.
- miR-382-5p downregulation in NXT-Exo contributes to its protective effect by targeting STC1.
- The TLR4/TRIF/NF-κB pathway is involved in NXT-Exo's protective mechanism.

## Abstract

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.

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.

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.

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.

Scientific workflow diagram showing experimental design beginning with mice treated with saline or a medication, exosome extraction, cell models exposed to LPS, and experimental analyses including endothelium, apoptosis, inflammation, and oxidation markers, as well as RNA sequencing and miRNA-omics visualized with plots, heatmaps, and Venn diagram.