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Decreased Macrophage Autophagy Promotes Liver Injury and Inflammation from Alcohol
Author(s) -
Ilyas Ghulam,
Cingolani Francesca,
Zhao Enpeng,
Tanaka Kathryn,
Czaja Mark J.
Publication year - 2019
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/acer.14041
Subject(s) - autophagy , inflammation , macrophage , liver injury , alcohol , medicine , chemistry , immunology , biochemistry , apoptosis , in vitro
Background One mechanism underlying the development of alcoholic liver disease is overactivation of the innate immune response. Recent investigations indicate that the lysosomal pathway of autophagy down‐regulates the inflammatory state of hepatic macrophages, suggesting that macrophage autophagy may regulate innate immunity in alcoholic liver disease. The function of macrophage autophagy in the development of alcoholic liver disease was examined in studies employing mice with a myeloid‐specific decrease in autophagy. Methods Littermate control and Atg5 Δmye mice lacking Atg5 ‐dependent myeloid autophagy were administered a Lieber–DeCarli control ( CD ) or ethanol diet ( ED ) alone or together with lipopolysaccharide ( LPS ) and examined for the degree of liver injury and inflammation. Results Knockout mice with decreased macrophage autophagy had equivalent steatosis but increased mortality and liver injury from ED alone. Increased liver injury and hepatocyte death also occurred in Atg5 Δmye mice administered ED and LPS in association with systemic inflammation as indicated by elevated serum levels of proinflammatory cytokines. Hepatic macrophage and neutrophil infiltration were unaffected by decreased autophagy, but levels of proinflammatory cytokine gene induction were significantly increased in the livers but not adipose tissue of knockout mice treated with ED and LPS . Inflammasome activation was increased in ED / LPS ‐treated knockout mice resulting in elevated interleukin ( IL )‐1β production. Increased IL ‐1β promoted alcoholic liver disease as liver injury was decreased by the administration of an IL ‐1 receptor antagonist. Conclusions Macrophage autophagy functions to prevent liver injury from alcohol. This protection is mediated in part by down‐regulation of inflammasome‐dependent and inflammasome‐independent hepatic inflammation. Therapies to increase autophagy may be effective in this disease through anti‐inflammatory effects on macrophages.