HADHA, the alpha subunit of the mitochondrial trifunctional protein, is involved in long-chain fatty acid-induced autophagy in intestinal epithelial cells.
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.
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Chiaki
C
Maeyashiki
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address: soshima.gast@tmd.ac.jp.
Shigeru
S
Oshima
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Kana
K
Otsubo
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Masanori
M
Kobayashi
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Yoichi
Y
Nibe
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Yu
Y
Matsuzawa
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan; Department of Advanced Therapeutics for GI Diseases, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Michio
M
Onizawa
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Yasuhiro
Y
Nemoto
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Takashi
T
Nagaishi
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan; Center for Stem Cell and Regenerative Medicine, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Ryuichi
R
Okamoto
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Kiichiro
K
Tsuchiya
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan; Department of Advanced Therapeutics for GI Diseases, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Tetsuya
T
Nakamura
Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Mamoru
M
Watanabe
D000818:Animals; D001343:Autophagy / Q000502:physiology*; D001600:Berberine Alkaloids / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D005227:Fatty Acids / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D063991:Mitochondrial Trifunctional Protein / Q000378:metabolism*; D021122:Protein Subunits
D001600:Berberine Alkaloids; D005227:Fatty Acids; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D021122:Protein Subunits; D063991:Mitochondrial Trifunctional Protein; C005413:palmatine
Autophagy; Cell death; HADHA; Inflammatory bowel disease; Long-chain fatty acids