title: Fatty-acid metabolism is involved in stress-resistance mechanisms of Caenorhabditis elegans.
abstract: Fatty acids are the major components of the phospholipid bilayer and are involved in several functions of cell membrane. We previously reported that fatty-acid metabolism is involved in the regulation of DAF-2/insulin signal in Caenorhabditis elegans. In this study, we investigate the role of fatty-acid metabolism in stress resistance with respect to daf-16 in nematode. We found that fatty-acid metabolism regulates heat, osmotic, and oxidative-stress resistance in C. elegans. RNA interference (RNAi) of fat-6, fat-7, and elo-2 enhanced heat resistance but decreased oxidative-stress tolerance. RNAi of fat-2 strongly increased osmotic-stress resistance, whereas nhr-49-RNAi remarkably reduced osmotic and oxidative-stress tolerance. In daf-16 mutants (mgDf50), RNAi of fat-2 and fat-7 increased viability under osmotic stress, while RNAi of fat-6, fat-7, and elo-2 enhanced heat resistance. Exposure of saturated fatty acids to RNAi worms of fat-1-, fat-7-, and nhr-49 increased osmotic resistance. On the other hand, polyunsaturated fatty acids (PUFAs) reduced osmotic-stress tolerance in fat-2-RNAi worms, whereas PUFAs enhanced it in nhr-49-RNAi worms. Heat-stress resistance in fat-6- and fat-7-RNAi worms was suppressed by oleic acid. These results suggest that stress-resistance mechanisms are regulated by fatty-acid metabolism with or without DAF-16 activity.
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Horikawa
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors; D018869:Heat-Shock Response; D007328:Insulin / Q000378:metabolism; D009997:Osmotic Pressure; D018384:Oxidative Stress; D034622:RNA Interference; D011972:Receptor, Insulin / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D005227:Fatty Acids; D051858:Forkhead Transcription Factors; D007328:Insulin; D014157:Transcription Factors; C108831:daf-16 protein, C elegans; C107483:DAF-2 protein, C elegans; D011972:Receptor, Insulin