Rapamycin enhances survival in a<i>Drosophila</i>model of mitochondrial disease

// Adrienne Wang 1 , Jacob Mouser 1 , Jason Pitt 1 , Daniel Promislow 1,2 and Matt Kaeberlein 1 1 University of Washington, Department of Pathology, Seattle, WA, USA 2 University of Washington, Department of Biology, Seattle, WA, USA Correspondence to: Matt Kaeberlein, email: // Keywords : mitochondria, leigh syndrome, mTOR(definition)-inhibiting drug studied for extending healthspan and lifespan." style="text-decoration:underline dotted; text-underline-offset:2px; cursor:help;">rapamycin(definition), Drosophila, complex I Received : August 08, 2016 Accepted : September 27, 2016 Published : October 11, 2016 Abstract Pediatric mitochondrial disorders are a devastating category of diseases caused by deficiencies in mitochondrial function. Leigh Syndrome (LS) is the most common of these diseases with symptoms typically appearing within the first year of birth and progressing rapidly until death, usually by 6-7 years of age. Our lab has recently shown that genetic inhibition of the mechanistic target of rapamycin (TOR) rescues the short lifespan of yeast mutants with defective mitochondrial function, and that pharmacological inhibition of TOR by administration of rapamycin significantly rescues the shortened lifespan, neurological symptoms, and neurodegeneration in a mouse model of LS. However, the mechanism by which TOR inhibition exerts these effects, and the extent to which these effects can extend to other models of mitochondrial deficiency, are unknown. Here, we probe the effects of TOR inhibition in a Drosophila model of complex I deficiency. Treatment with rapamycin robustly suppresses the lifespan defect in this model of LS, without affecting behavioral phenotypes. Interestingly, this increased lifespan in response to TOR inhibition occurs in an autophagy(definition)-independent manner. Further, we identify a fat storage defect in the ND2 mutant flies that is rescued by rapamycin, supporting a model that rapamycin exerts its effects on mitochondrial disease in these animals by altering metabolism.