# Microvesicles from quiescent and TGF-β1 stimulated hepatic stellate cells: Divergent impact on hepatic vascular injury

## TL;DR

This study shows that microvesicles from resting liver cells protect blood vessels, while those from TGF-β1-stimulated cells worsen liver injury.

## Contribution

The study reveals divergent effects of microvesicles from quiescent versus TGF-β1-stimulated hepatic stellate cells on vascular injury.

## Key findings

- Quiescent HSC-MVs protect endothelial cells and reduce liver injury in rats.
- TGF-β1-stimulated HSC-MVs increase cytotoxicity and worsen liver damage.
- Effects are mediated through pathways like PI3K/AKT/VEGF and MEK/ERK/eNOS.

## Abstract

This study evaluated the effect of microvesicles(MVs) from quiescent and TGF-β1 stimulated hepatic stellate cells (HSC-MVs, TGF-β1HSC-MVs) on H2O2-induced human umbilical vein endothelial cells (HUVECs) injury and CCl4-induced rat hepatic vascular injury.

HUVECs were exposed to hydrogen peroxide (H2O2) to establish a model for vascular endothelial cell injury. HSC-MVs or TGF-β1HSC-MVs were co-cultured with H2O2-treated HUVECs, respectively. Indicators including cell survival rate, apoptosis rate, oxidative stress, migration, invasion, and angiogenesis were measured. Simultaneously, the expression of proteins such as PI3K, AKT, MEK1+MEK2, ERK1+ERK2, VEGF, eNOS, and CXCR4 was assessed, along with activated caspase-3. SD rats were intraperitoneally injected with CCl4 twice a week for 10 weeks to induce liver injury models. HSC-MVs or TGF-β1HSC-MVs were injected into the tail vein of rats. Liver and hepatic vascular damage were also detected.

In H2O2-treated HUVECs, HSC-MVs increased cell viability, reduced cytotoxicity and apoptosis, improved oxidative stress, migration, and angiogenesis, and upregulated protein expression of PI3K, AKT, MEK1/2, ERK1/2, VEGF, eNOS, and CXCR4. Conversely, TGF-β1HSC-MVs exhibited opposite effects. CCl4- induced rat hepatic injury model, HSC-MVs reduced the release of ALT and AST, hepatic inflammation, fatty deformation, and liver fibrosis. HSC-MVs also downregulated the protein expression of CD31 and CD34. Conversely, TGF-β1HSC-MVs demonstrated opposite effects.

HSC-MVs demonstrated a protective effect on H2O2-treated HUVECs and CCl4-induced rat hepatic injury, while TGF-β1HSC-MVs had an aggravating effect. The effects of MVs involve PI3K/AKT/VEGF, CXCR4, and MEK/ERK/eNOS pathways.