Blood-derived macrophages prone to accumulate lysosomal lipids trigger oxLDL-dependent murine hepatic inflammation

Sci Rep. 2017 Oct 2;7(1):12550. doi: 10.1038/s41598-017-13058-z.

Abstract

Despite the consistent rise of non-alcoholic steatohepatitis (NASH) worldwide, the mechanisms that govern the inflammatory aspect of this disease remain unknown. Previous research showed an association between hepatic inflammation and lysosomal lipid accumulation in blood-derived hepatic macrophages. Additionally, in vitro findings indicated that lipids, specifically derived from the oxidized low-density lipoprotein (oxLDL) particle, are resistant to removal from lysosomes. On this basis, we investigated whether lysosomal lipid accumulation in blood-derived hepatic macrophages is causally linked to hepatic inflammation and assessed to what extent increasing anti-oxLDL IgM autoantibodies can affect this mechanism. By creating a proof-of-concept mouse model, we demonstrate a causal role for lysosomal lipids in blood-derived hepatic macrophages in mediating hepatic inflammation and initiation of fibrosis. Furthermore, our findings show that increasing anti-oxLDL IgM autoantibody levels reduces inflammation. Hence, therapies aimed at improving lipid-induced lysosomal dysfunction and blocking oxLDL-formation deserve further investigation in the context of NASH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autoantibodies / biosynthesis
  • Autoantibodies / immunology
  • Autoantibodies / therapeutic use
  • Cholesterol / metabolism
  • Disease Models, Animal
  • Humans
  • Immunoglobulin M / biosynthesis
  • Immunoglobulin M / immunology
  • Inflammation / blood
  • Inflammation / complications
  • Inflammation / metabolism*
  • Inflammation / therapy
  • Kupffer Cells / metabolism
  • Lipids / blood
  • Lipoproteins, LDL / antagonists & inhibitors
  • Lipoproteins, LDL / immunology
  • Lipoproteins, LDL / metabolism*
  • Liver / metabolism
  • Liver / pathology
  • Lysosomes / metabolism
  • Macrophages / metabolism*
  • Macrophages / pathology
  • Mice
  • Non-alcoholic Fatty Liver Disease / blood
  • Non-alcoholic Fatty Liver Disease / metabolism*
  • Non-alcoholic Fatty Liver Disease / pathology
  • Non-alcoholic Fatty Liver Disease / therapy

Substances

  • Autoantibodies
  • Immunoglobulin M
  • Lipids
  • Lipoproteins, LDL
  • oxidized low density lipoprotein
  • Cholesterol