NHR-8 regulated P-glycoproteins uncouple xenobiotic stress resistance from longevity in chemosensory C. elegans mutants
AbstractLongevity is often associated with stress resistance, but whether they are causally linked is incompletely understood. Here we investigate chemosensory defective Caenorhabditis elegans mutants that are long-lived and stress resistant. We find that mutants in the intraflagellar transport protein gene osm-3 were significantly protected from tunicamycin-induced ER stress. While osm-3 lifespan extension is dependent on the key longevity factor DAF-16/FOXO, tunicamycin resistance was not. osm-3 mutants are protected from bacterial pathogens, which is pmk-1 p38 MAP kinase dependent while TM resistance was pmk-1 independent. Inhibition of P-glycoproteins with verapamil suppressed tunicamycin resistance and expression of P-glycoprotein xenobiotic detoxification genes was elevated in osm-3 mutants. The nuclear hormone receptor nhr-8 was necessary and sufficient to regulate P-glycoproteins and tunicamycin resistance in a cholesterol-dependent fashion. We thus identify a cell-nonautonomous regulation of xenobiotic detoxification and show that separate pathways are engaged to mediate longevity, pathogen resistance, and xenobiotic detoxification in osm-3 mutants.