Characterization of immune cell populations in the microenvironment of mice liver during the progression of liver fibrosis to hepatocellular carcinoma
(2024) EASL CONGRESS — Location: Milan, Italie (5.June.2024)
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- Authors
Sokal, Etienne 
- Abstract
- Background and Aims: Around 90% of hepatocellular carcinoma (HCC) cases arise in the background of chronic liver diseases (CLD). Chronic inflammation is the underlying cause of CLD and development of HCC. Thus, dysregulated functions of hepatic immune cell populations are playing important roles in CLD and development. In this study we aim to characterize the different immune cell populations dysregulated during liver fibrosis and HCC development using a combination of Diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) treated mouse model. Method: A single injection of DEN at 4 weeks of age, followed by continuous injections of CCl4 for 6 and 21 weeks were administered respectively, to induce liver fibrosis and HCC in mice. Whole liver was perfused and digested using collagenase, to isolate and characterise single-cell suspensions of the non-parenchymal cell fraction (NPF). The different immune cell populations were then identified and sorted using FACS analysis. In parallel, the tissular hepatic immune cells were identified using specific cell surface and nuclear antibody markers and their spatial localisation evaluated using multiplex immunofluorescence on formalin fixed paraffin embedded (FFPE) liver sections. Results: Based on the FACS analysis results, it was observed that the overall leukocyte population has drastically increased as the disease progressed from liver fibrosis to HCC in comparison to non-treated livers. Among the leukocytes, myeloid cell populations decreased due to a drastic loss of the Kupffer cell (KC) population during the disease progression, while infiltrating monocyte-derived macrophages, monocytes, and granulocyte populations increased. The lymphocyte population increases which seems to be related to an overall increase of the CD4+ T cell population than the one of CD8+ T cells. Our multiplex immunofluorescence results suggest that all the immune cell populations were distributed near the central vein, which is the site of inflammation in fibrotic mice liver. In HCC liver, immune cells like CD8T cells and granulocytes were found more within the tumor tissue, the hepatic macrophages were distributed throughout the liver parenchyma while Tregs, were more abundant in the invasive margin of the tumor and in the remaining tissue. Conclusion: By FACS analysis, we observed that the overall populations of different immune cells had significantly dysregulated. By multiplex fluorescence staining the majority of the immune cells were identified to be distributed at the site of inflammation in fibrosis group. In HCC livers, the different immune cell populations were heterogeneously distributed within the tumor, the invasive margin of the tumor or the remaining parts of the liver tissue based on their specific pro-inflammatory and anti-inflammatory properties.
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Citations
Ajith, A., Smets, F., Sokal, E., & Najimi, M. (2024). Characterization of immune cell populations in the microenvironment of mice liver during the progression of liver fibrosis to hepatocellular carcinoma. EASL CONGRESS, Milan, Italie. https://hdl.handle.net/2078.5/214409