Intestinal Cgi-58 deficiency reduces postprandial lipid absorption

PLoS One. 2014 Mar 11;9(3):e91652. doi: 10.1371/journal.pone.0091652. eCollection 2014.

Abstract

Comparative Gene Identification-58 (CGI-58), a lipid droplet (LD)-associated protein, promotes intracellular triglyceride (TG) hydrolysis in vitro. Mutations in human CGI-58 cause TG accumulation in numerous tissues including intestine. Enterocytes are thought not to store TG-rich LDs, but a fatty meal does induce temporary cytosolic accumulation of LDs. Accumulated LDs are eventually cleared out, implying existence of TG hydrolytic machinery in enterocytes. However, identities of proteins responsible for LD-TG hydrolysis remain unknown. Here we report that intestine-specific inactivation of CGI-58 in mice significantly reduces postprandial plasma TG concentrations and intestinal TG hydrolase activity, which is associated with a 4-fold increase in intestinal TG content and large cytosolic LD accumulation in absorptive enterocytes during the fasting state. Intestine-specific CGI-58 knockout mice also display mild yet significant decreases in intestinal fatty acid absorption and oxidation. Surprisingly, inactivation of CGI-58 in intestine significantly raises plasma and intestinal cholesterol, and reduces hepatic cholesterol, without altering intestinal cholesterol absorption and fecal neutral sterol excretion. In conclusion, intestinal CGI-58 is required for efficient postprandial lipoprotein-TG secretion and for maintaining hepatic and plasma lipid homeostasis. Our animal model will serve as a valuable tool to further define how intestinal fat metabolism influences the pathogenesis of metabolic disorders, such as obesity and type 2 diabetes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 1-Acylglycerol-3-Phosphate O-Acyltransferase / deficiency*
  • 1-Acylglycerol-3-Phosphate O-Acyltransferase / genetics
  • Animals
  • Cholesterol / blood
  • Cholesterol / metabolism
  • Enterocytes / metabolism
  • Fatty Acids / metabolism
  • Female
  • Hydrolysis
  • Intestinal Absorption / genetics*
  • Intestinal Mucosa / metabolism*
  • Intestine, Small / metabolism
  • Intestine, Small / pathology
  • Intestines / pathology
  • Lipase / metabolism
  • Lipid Metabolism / genetics*
  • Male
  • Mice
  • Mice, Knockout
  • Oxidation-Reduction
  • Postprandial Period*
  • Triglycerides / metabolism

Substances

  • Fatty Acids
  • Triglycerides
  • Cholesterol
  • 1-Acylglycerol-3-Phosphate O-Acyltransferase
  • Abhd5 protein, mouse
  • Lipase