HADHA, the alpha subunit of the mitochondrial trifunctional protein, is involved in long-chain fatty acid-induced autophagy in intestinal epithelial cells

Biochem Biophys Res Commun. 2017 Mar 11;484(3):636-641. doi: 10.1016/j.bbrc.2017.01.159. Epub 2017 Jan 30.


Genome-wide association studies have identified autophagy-related susceptibility genes for inflammatory bowel disease (IBD); however, whether autophagy regulators can be utilized as therapeutic targets remains unclear. To identify novel microtubule-associated protein 1 light chain 3 (LC3)-interacting proteins in intestinal epithelial cells (IECs), we isolated primary IECs from green fluorescent protein (GFP)-LC3 mice. We performed immunoprecipitation with a GFP antibody and then analyzed co-immunoprecipitates by mass spectrometry. HADHA was identified as an LC3-interacting protein from primary IECs. The HADHA gene encodes the alpha subunit of the mitochondrial trifunctional protein. Given that HADHA catalyzes the last three steps of mitochondrial beta-oxidation of long-chain fatty acids, we investigated whether long-chain fatty acids induce autophagy in IECs. We found that palmitic acid induced autophagy in DLD-1, HT29, and HCT116 cells. HADHA was expressed in not only the mitochondria but also the cytosol. LC3 puncta co-localized with HADHA, which were enhanced by palmitic acid stimulation. However, LC3 puncta did not co-localize with Tom20, suggesting that HADHA was induced to associate with LC3 puncta at sites other than the mitochondria. Thus, HADHA may have extra-mitochondrial functions. Furthermore, we found that palmitic acid induced cell death in IECs, which was accelerated by bafilomycin A and chloroquine. These findings suggested that palmitic acid-induced autophagy supports the survival of IECs. Taken together, these results suggested that HADHA is involved in long-chain fatty acid-induced autophagy in IECs, thus providing new insights into the pathology of IBD and revealing novel therapeutic targets of IBD.

Keywords: Autophagy; Cell death; HADHA; Inflammatory bowel disease; Long-chain fatty acids.

MeSH terms

  • Animals
  • Autophagy / physiology*
  • Berberine Alkaloids / pharmacology
  • Epithelial Cells / metabolism
  • Epithelial Cells / pathology
  • Fatty Acids / metabolism*
  • Intestinal Mucosa / metabolism*
  • Intestinal Mucosa / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Microtubule-Associated Proteins / metabolism*
  • Mitochondrial Trifunctional Protein / metabolism*
  • Protein Subunits


  • Berberine Alkaloids
  • Fatty Acids
  • Map1lc3b protein, mouse
  • Microtubule-Associated Proteins
  • Protein Subunits
  • Mitochondrial Trifunctional Protein
  • palmatine