# Hepsin as a potential therapeutic target for alleviating acetaminophen-induced hepatotoxicity via gap-junction regulation and oxidative stress modulation

## TL;DR

This study shows that hepsin, a type of protease, can protect against liver damage caused by acetaminophen overdose by regulating gap junctions and reducing oxidative stress.

## Contribution

The study identifies hepsin as a novel therapeutic target for treating acetaminophen-induced liver injury through gap-junction regulation and oxidative stress modulation.

## Key findings

- Hepsin deficiency in mice worsens acetaminophen toxicity, causing severe liver damage and higher mortality.
- Hepsin reduces liver injury by modulating gap junctions and oxidative stress, offering protection against acetaminophen-induced hepatotoxicity.

## Abstract

Acetaminophen (APAP) overdose is a leading cause of drug-induced liver damage, highlighting the limitations of current emergency treatments that primarily involve administering the glutathione precursor N-acetylcysteine and supportive therapy. This study highlights the essential protective role of the type II transmembrane serine protease (TTSP), hepsin, in mitigating acetaminophen-induced liver injury, particularly through its regulation of gap junction (GJ) abundance in response to reactive oxygen stress in the liver. We previously reported that reduced levels of activated hepatocyte growth factor and the c-Met receptor tyrosine kinase—both of which are vital for maintaining cellular redox balance—combined with increased expression of GJ proteins in hepsin-deficient mice. Here, we show that hepsin deficiency in mice exacerbates acetaminophen toxicity compared to wild-type mice, leading to more severe liver pathology, elevated oxidative stress, and greater mortality within 6 h after exposure. Administering hepsin had a protective effect in both mouse models, reducing hepatotoxicity by modulating GJ abundance. Additionally, transcriptome analysis and a functional GJ inhibitor have highlighted hepsin's mechanism for managing oxidative stress. Combining hepsin with relatively low doses of N-acetylcysteine had a synergistic effect that was more efficacious than high-dose N-acetylcysteine alone. Our results illustrate the crucial role of hepsin in modulating the abundance of hepatic GJs and reducing oxidative stress, thereby offering early protection against acetaminophen-induced hepatotoxicity and a new, combination approach. Emerging as a promising therapeutic target, hepsin holds potential for combination therapy with N-acetylcysteine, paving the way for novel approaches in managing drug-induced liver injury.

1. Hepsin−/− mice exhibit exacerbated APAP toxicity, resulting in more severe liver damage, elevated oxidative stress, and higher mortality.

2. Hepsin is crucial in protecting against APAP-induced liver injury by regulating gap junctions and reducing oxidative stress.

3. Combining hepsin with low doses of N-acetylcysteine provides greater protection against APAP-induced hepatotoxicity than high-dose NAC alone.

The online version contains supplementary material available at 10.1007/s10565-024-09915-z.