Modulation of Liver Inflammation and Fibrosis by Interleukin-37.

Abstract

Background and Aims: Chronic inflammation induces liver fibrosis, cirrhosis and potentially liver cancer. Kupffer cells modulate hepatic stellate cells by secreting immunologically active proteins as TGF-β. TGF-β promotes liver fibrosis via the activation of Sma- and Mad-related protein 3. IL-37 broadly suppresses innate and adaptive immune responses. Intracellular IL-37 interacts with Smad3. We hypothesize that IL-37 downregulates the activation of hepatic Kupffer and stellate cells and interferes with the TGF-β signaling cascade to modulate liver fibrogenesis. Methods: The role of IL-37 on liver inflammation and fibrogenesis was assessed in three mouse models as well as isolated Kupffer- and stellate cells. Serum IL-37 was tested by ELISA in a clinical cohort and correlated with liver disease severity. Results: Transgene expression of IL-37 in mice extends survival, reduces hepatic damage, expression of early markers of fibrosis and histologically assessed liver fibrosis after bile duct ligation. IL-37tg mice were protected against CCl4-induced liver inflammation. Colitis-associated liver inflammation and fibrosis was less severe in IL-10 knockout IL-37tg mice. Spontaneous and LPS/TGF-β-induced cytokine release and profibrogenic gene expression was lower in HSC and KC isolated from IL-37tg mice and IL-37 overexpressing, IL-1β stimulated human LX-2 stellate cells. However, administration of recombinant human IL-37 did not modulate fibrosis pathways after BDL in mice, LX2 cells or murine HSCs. In a large clinical cohort, we observed a positive correlation of serum IL-37 levels with disease severity in liver cirrhosis. Conclusions: Predominantly intracellular IL-37 downregulates liver inflammation and fibrosis. The correlation of serum IL-37 with disease severity in cirrhosis suggests its potential as a novel target modulating the course of liver fibrosis.

• Authors: Steffeni Mountford, Maria Effenberger, Heidi Noll-Puchta, Lucas Griessmair, Andrea Ringleb, Sonja Haas, Gerald Denk, Florian P Reiter, Doris Mayr, Charles A Dinarello, Herbert Tilg, Philip Bufler
• Journal: Frontiers in immunology (Front Immunol) Vol. 12 Pg. 603649 ( 2021) ISSN: 1664-3224 [Electronic] Switzerland
• PMID: 33746950 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 Mountford, Effenberger, Noll-Puchta, Griessmair, Ringleb, Haas, Denk, Reiter, Mayr, Dinarello, Tilg and Bufler.

Chemical References

• IL37 protein, human
• Interleukin-1
• Transforming Growth Factor beta

Topics

• Animals
• Disease Models, Animal
• Hepatitis (genetics, immunology, pathology)
• Humans
• Inflammation (genetics, immunology, pathology)
• Interleukin-1 (genetics, immunology)
• Kupffer Cells (immunology, pathology)
• Liver Cirrhosis (genetics, immunology, pathology)
• Mice
• Mice, Knockout
• Transforming Growth Factor beta (genetics, immunology)