Lysosomal cholesterol overload in macrophages promotes liver fibrosis in a mouse model of NASH.

Abstract

Accumulation of lipotoxic lipids, such as free cholesterol, induces hepatocyte death and subsequent inflammation and fibrosis in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms remain unclear. We have previously reported that hepatocyte death locally induces phenotypic changes in the macrophages surrounding the corpse and remnant lipids, thereby promoting liver fibrosis in a murine model of NASH. Here, we demonstrated that lysosomal cholesterol overload triggers lysosomal dysfunction and profibrotic activation of macrophages during the development of NASH. β-cyclodextrin polyrotaxane (βCD-PRX), a unique supramolecule, is designed to elicit free cholesterol from lysosomes. Treatment with βCD-PRX ameliorated cholesterol accumulation and profibrotic activation of macrophages surrounding dead hepatocytes with cholesterol crystals, thereby suppressing liver fibrosis in a NASH model, without affecting the hepatic cholesterol levels. In vitro experiments revealed that cholesterol-induced lysosomal stress triggered profibrotic activation in macrophages predisposed to the steatotic microenvironment. This study provides evidence that dysregulated cholesterol metabolism in macrophages would be a novel mechanism of NASH.

• Authors: Michiko Itoh, Atsushi Tamura, Sayaka Kanai, Miyako Tanaka, Yohei Kanamori, Ibuki Shirakawa, Ayaka Ito, Yasuyoshi Oka, Isao Hidaka, Taro Takami, Yasushi Honda, Mitsuyo Maeda, Yasuyuki Saito, Yoji Murata, Takashi Matozaki, Atsushi Nakajima, Yosky Kataoka, Tomoo Ogi, Yoshihiro Ogawa, Takayoshi Suganami
• Journal: The Journal of experimental medicine (J Exp Med) Vol. 220 Issue 11 (11 06 2023) ISSN: 1540-9538 [Electronic] United States
• PMID: 37725372 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2023 Itoh et al.

Chemical References

• polyrotaxane
• Cholesterol

Topics

• Animals
• Mice
• Non-alcoholic Fatty Liver Disease
• Disease Models, Animal
• Liver Cirrhosis
• Macrophages
• Cholesterol
• Lysosomes