Adipose dysfunction with aging increases risk to insulin resistance and other chronic metabolic diseases. We previously showed functional changes in microRNAs involved in pre-adipocyte differentiation with aging resulting in adipose dysfunction. However, the mechanisms leading to this dysfunction in microRNAs in adipose tissue (adipomiRs) during aging are not well understood. We determined the longitudinal changes in expression of adipomiRs and studied their regulatory mechanisms, such as miRNA biogenesis and editing, in an aging rodent model, with Fischer344 × Brown-Norway hybrid rats at ages ranging from 3 to 30 months (male/females, n > 8). Expression of adipomiRs and their edited forms were determined by small-RNA sequencing. RT-qPCR was used to measure the mRNA expression of biogenesis and editing enzymes. Sanger sequencing was used to validate editing with aging. Differential expression of adipomiRs involved in adipocyte differentiation and insulin signaling was altered with aging. Sex- and age-specific changes in edited adipomiRs were observed. An increase in miRNA biogenesis and editing enzymes (ADARs and their splice variants) were observed with increasing age, more so in female than male rats. The adipose dysfunction observed with age is attributed to differences in editing of adipomiRs, suggesting a novel regulatory pathway in aging.

Obesity is a major crisis in the Appalachian region. Being obese not only increases risk to heart disease and diabetes, but also promotes behavior modifications. Behavior changes such as excess food consumption, stress, depression is very commonly observed among obese individuals. We hypothesized, lower redox stress by modulating appetite regulation will decrease obesity associated behavioral stress. Behavior changes and appetite regulation were determined in C57Bl6 mice (control) and Bob-Cat mice that express high antioxidant catalase in an obese (Ob/Ob) background (stress-less mouse) (n=6-8) fed either normal chow (NC) or high-fat (HF-45% lard-TD06415) diet for eight weeks. Weekly body weights were monitored. Fat mass changes were determined using ECHO-MRI. Comprehensive lab animal monitoring system (CLAMS) was used to determine energy expenditure. Motor and anxiety-like behavior was tested using Open Field (locomotor behavior) and Rota-Rod (motor coordination and strength) testing systems at baseline and 8 weeks. Changes in appetite regulating genes in the hypothalamus were determined using real time PCR. The C57Bl6 mice on the NC stayed longer on the Rota-Rod as the weeks progressed compared to the mice on HF, where the effect was more dependent on the trials (learning) rather on endurance. The Open Field test showed that the C57Bl6 mice on HF diet were more anxious (spent more time in the edges rather than center) compared to the mice on NC. Catalase overexpression lowered levels of anxiety but had less endurance levels in the HF fed mice. CLAMS showed heat production was higher in stress-less mice vs C57Bl6. Catalase overexpression showed an induction in anorexigenic POMC, and decrease in orexigenic Npy vs C57Bl6. Redox regulation in the stress-less mice modulated both hypothalamic appetite regulation and behavior changes associated with obesity. These findings suggest that redox modulation, may be regulating metabolic pathways that lower obesity and improve the overall behavioral and nutritive state.