INVESTIGATING MITOCONDRIAL AUTOPHAGY AFTER VOLUNTARY WHEEL RUNNING IN WESTERN DIET FED MICE

Megan E. Rosa, David E. Lee, Jacob L. Brown, Richard A. Perry, Jr, Lemuel A. Brown, Jordyn N. Henry, Tyrone A. Washington & Nicholas P. Greene University of Arkansas, Fayetteville, Arkansas Americans are chronically overfed and underactive, leading to a substantial increase in obesity and metabolic diseases. Mitochondrial function and quality are regulated by several processes. Specifically, damaged mitochondria are removed by autophagy, which has been cited as important mechanism in many metabolic and neuronal diseases. Exercise training has previously been reported to enhance autophagy flux in otherwise healthy animals. PURPOSE: To evaluate the effects of Western Diet and physical activity on autophagy, specifically with regards to mitochondrial autophagy. METHODS: Eight week old wild type C57BL6/J mice were divided into two groups, normal rodent chow (NC) (54% CHO, 17% fat) and Western Diet (WD) (42% fat plus 1.5g cholesterol/kg) and allowed ad libitum consumption of assigned diet for four weeks. After four weeks, animals were further subdivided into Voluntary Wheel Running (VWR) or Sedentary (SED) groups. VWR animals were allowed free access to a running wheel for four weeks, after which all animals were euthanized and gastrocnemius were collected for analysis. Glucose tolerance tests confirmed diabetes in WD-SED animals. Quantitative real-time PCR analysis was used to examine genes of autophagy machinery including Beclin, Atg7 and Bnip3 (mitochondrial autophagy specific). Data were analyzed by 2X2 ANOVA (diet [NC vs. WD] X activity [SED vs. VWR]) with α set at PRESULTS: There were no significant differences in gene expression of the autophagy machinery among groups. CONCLUSIONS: Neither Western diet nor voluntary wheel running appear to have an effect on gene expression of autophagy machinery after eight or four weeks of intervention respectively. Genetic machinery is only one aspect of autophagy, there are other aspects of autophagy, such as autophagy flux, that have yet to be investigated in this type of model and warrant further investigation