The Drosophila aryl hydrocarbon receptor ortholog, spineless, modulates survival and reproduction.

The aryl hydrocarbon receptor (AhR) is a highly conserved, ligand-activated transcription factor in mammals involved in multiple physiological processes, including development, xenobiotic detoxification, and potentially aging, and some of the most potent activators of AhR are tryptophan metabolites. AhR manipulation across species has been shown to have conflicting results on aging phenotypes that are often tissue specific. To expand our understanding of AhR and aging, we studied AhR affects survival and reproduction in Drosophila melanogaster, whose genome contains an ortholog of AhR, spineless (ss). Our findings indicate that ss-deficient flies have a shorter lifespan than wildtype flies but interestingly exhibit reduced mortality until approximately 40 days of age. Similarly, ss-deficient flies are more stress resistant than wildtype at young ages, but this reverses in later age. Negative lifespan-shortening effects of tryptophan metabolites were mitigated in ss-deficient flies, suggesting that the effects of these metabolites are ss-reliant, similar to AhR in mammals. Overall, our preliminary work demonstrates an evolutionarily conserved role for AhR in the aging process and increases our knowledge of the role of AhR/ss on aging phenotypes.