# HepG2 cells stimulated by THP-1-conditioned medium: a potential in vitro model of systemic inflammation–induced hepatic alterations

## TL;DR

This study creates an in vitro model using HepG2 cells and THP-1-conditioned medium to study how systemic inflammation affects liver metabolism and lipoprotein changes.

## Contribution

A novel in vitro model is developed to study inflammation-induced hepatic metabolic changes under conditions mimicking systemic inflammation.

## Key findings

- Short-term exposure to THP-1-conditioned medium altered inflammatory gene and transcription factor mRNA expression in HepG2 cells.
- Lipoprotein-associated gene expression was significantly modified at different time points following exposure.
- The model showed no effect on HepG2 cell viability after 24 hours of exposure.

## Abstract

Chronic inflammatory diseases are associated with qualitative and quantitative changes in lipid and lipoprotein metabolism, including high density lipoproteins (HDLs), increasing patients´ susceptibility to atherosclerosis and cardiovascular mortality. Given the liver’s central role in lipoprotein metabolism and systemic inflammation, we aimed to develop and investigate an in vitro model of inflammation-induced hepatic metabolic changes.

To better approximate in vivo conditions, where systemic inflammation exposes the liver to a complex environment rich in cytokines and inflammatory mediators, we exposed human hepatocarcinoma HepG2 cells to conditioned media (CM) from THP-1-derived macrophages using phorbol-12-myristate-13-acetate (PMA) and lipopolysaccharide (LPS). The effect of CM on mRNA expression in HepG2 was tested by quantitative real-time PCR or protein expression by Western blot analysis. Even short-term exposure to CM (2–4 h) led to a significant change in the mRNA expression of inflammatory genes and several transcription factors (e.g., TNF-α, NF-κB, PPARα, and LRH-1). This change was accompanied by alternations in the expression of lipoprotein-associated genes at different time points (e.g. SAA, LDLr, ApoA1, ABCA1, PON1, and PCSK9). After 24 h of exposure, no effect on HepG2 viability was observed.

In our model, we observed several significant inflammation-induced changes in hepatic lipoprotein metabolism, making it a valuable in vitro system for further mechanistic studies.

The online version contains supplementary material available at 10.1007/s11033-026-11641-0.