Abstract
Aging and age-related diseases occur in almost all organisms. Recently, it was discovered that the inhibition of target of rapamycin complex 1 (TORC1), a conserved complex that mediates nutrient status and cell metabolism, can extend an individual's lifespan and inhibit age-related diseases in many model organisms. However, the mechanism whereby TORC1 affects aging remains elusive. Here, we use a loss-of-function mutation in nprl2, a component of GATOR1 that mediates amino acid levels and inhibits TORC1 activity, to investigate the effect of increased TORC1 activity on the occurrence of age-related digestive dysfunction in Drosophila. We found that the nprl2 mutation decreased Drosophila lifespan. Furthermore, the nprl2 mutant had a distended crop, with food accumulation at an early age. Interestingly, the inappropriate food distribution and digestion along with decreased crop contraction in nprl2 mutant can be rescued by decreasing TORC1 activity. In addition, nprl2-mutant flies exhibited age-related phenotypes in the midgut, including short gut length, a high rate of intestinal stem cell proliferation, and metabolic dysfunction, which could be rescued by inhibiting TORC1 activity. Our findings showed that the gastrointestinal tract aging process is accelerated in nprl2-mutant flies, owing to high TORC1 activity, which suggested that TORC1 promotes digestive tract senescence.
