Glucose or Altered Ceramide Biosynthesis Mediate Oxygen Deprivation Sensitivity Through Novel Pathways Revealed by Transcriptome Analysis in Caenorhabditis elegans

Individuals with type 2 diabetes display metabolic abnormalities, such as hyperglycemia, increased free fatty acids, insulin resistance, and altered ceramide levels, that contribute to vascular dysfunctions and compromised oxygen delivery. Caenorhabditis elegans fed a glucose-supplemented diet or with altered ceramide metabolism, due to a hyl-2 mutation, are sensitive to oxygen deprivation (anoxia). Our experiments showed that the combination of these factors further decreased the anoxia survival. RNA-sequencing analysis was performed to assess how a glucose-supplemented diet and/or a hyl-2 mutation altered the transcriptome. Comparison analysis of transcripts associated with anoxia-sensitive animals [hyl-2(tm2031) mutation or a glucose diet] revealed 199 common transcripts encoded by genes with known or predicted functions involving innate immunity, cuticle function (collagens), or xenobiotic and endobiotic phase I and II detoxification system. Use of RNA interference (RNAi) to target gene products of the xenobiotic and endobiotic phase I and II detoxification system (UDP-glycosyltransferase and Cytochrome p450 genes; ugt-15, ugt-18, ugt-19, ugt-41, ugt-63, cyp-13A12, cyp-25A1, and cyp-33C8) increased anoxia survival in wild-type animals fed a standard diet. Anoxia sensitivity of the hyl-2(tm2031) animals was suppressed by RNAi of cyp-25A1 or cyp-33C8 genes. A glucose diet fed to the P0 hermaphrodite decreased the anoxia survival of its F1 embryos; however, the RNAi of ugt-63 and cyp-33C8 suppressed anoxia sensitivity. These studies provide evidence that the detoxification system impacts oxygen deprivation responses and that C. elegans can be used to model the conserved detoxification system.