» Articles » PMID: 38919611

Profibrogenic Role of IL-15 Through IL-15 Receptor Alpha-mediated Trans-presentation in the Carbon Tetrachloride-induced Liver Fibrosis Model

Overview
Journal Front Immunol
Date 2024 Jun 26
PMID 38919611
Authors
Affiliations
Soon will be listed here.
Abstract

Background: Inflammatory cytokines play key pathogenic roles in liver fibrosis. IL-15 is a proinflammatory cytokine produced by myeloid cells. IL-15 promotes pathogenesis of several chronic inflammatory diseases. However, increased liver fibrosis has been reported in mice lacking IL-15 receptor alpha chain (IL-15Rα), suggesting an anti-fibrogenic role for IL-15. As myeloid cells are key players in liver fibrosis and IL-15 signaling can occur independently of IL-15Rα, we investigated the requirement of IL-15 and IL-15Rα in liver fibrosis.

Methods: We induced liver fibrosis in , and wildtype C57BL/6 mice by the administration of carbon tetrachloride (CCl). Liver fibrosis was evaluated by Sirius red and Mason's trichrome staining and α-smooth muscle acting immunostaining of myofibroblasts. Gene expression of collagens, matrix modifying enzymes, cytokines and chemokines was quantified by RT-qPCR. The phenotype and the numbers of intrahepatic lymphoid and myeloid cell subsets were evaluated by flow cytometry.

Results: Both and mice developed markedly reduced liver fibrosis compared to wildtype control mice, as revealed by reduced collagen deposition and myofibroblast content. mice showed further reduction in collagen deposition compared to mice. However, and genes were similarly induced in the fibrotic livers of wildtype, and mice, although notable variations were observed in the expression of matrix remodeling enzymes and chemokines. As expected, and mice showed markedly reduced numbers of NK cells compared to wildtype mice. They also showed markedly less staining of CD45 immune cells and CD68 macrophages, and significantly reduced inflammatory cell infiltration into the liver, with fewer pro-inflammatory and anti-inflammatory monocyte subsets compared to wildtype mice.

Conclusion: Our findings indicate that IL-15 exerts its profibrogenic role in the liver by promoting macrophage activation and that this requires trans-presentation of IL-15 by IL-15Rα.

References
1.
Bobbala D, Chen X, Leblanc C, Mayhue M, Stankova J, Tanaka T . Interleukin-15 plays an essential role in the pathogenesis of autoimmune diabetes in the NOD mouse. Diabetologia. 2012; 55(11):3010-20. DOI: 10.1007/s00125-012-2675-1. View

2.
Koda Y, Teratani T, Chu P, Hagihara Y, Mikami Y, Harada Y . CD8 tissue-resident memory T cells promote liver fibrosis resolution by inducing apoptosis of hepatic stellate cells. Nat Commun. 2021; 12(1):4474. PMC: 8298513. DOI: 10.1038/s41467-021-24734-0. View

3.
Devocelle A, Lecru L, Francois H, Desterke C, Gallerne C, Eid P . Inhibition of TGF-1 Signaling by IL-15: A Novel Role for IL-15 in the Control of Renal Epithelial-Mesenchymal Transition: IL-15 Counteracts TGF-1-Induced EMT in Renal Fibrosis. Int J Cell Biol. 2019; 2019:9151394. PMC: 6642769. DOI: 10.1155/2019/9151394. View

4.
Pellicoro A, Ramachandran P, Iredale J, Fallowfield J . Liver fibrosis and repair: immune regulation of wound healing in a solid organ. Nat Rev Immunol. 2014; 14(3):181-94. DOI: 10.1038/nri3623. View

5.
Kautzman A, Mobulakani J, Marrero Cofino G, Quenum A, Cayarga A, Asselin C . Interleukin 15 in murine models of colitis. Anat Rec (Hoboken). 2022; 306(5):1111-1130. DOI: 10.1002/ar.25044. View