Common mechanisms for calorie restriction and adenylyl cyclase type 5 knockout models of longevity

Summary Adenylyl cyclase type 5 knockout mice ( AC 5 KO ) live longer and are stress resistant, similar to calorie restriction ( CR ). AC 5 KO mice eat more, but actually weigh less and accumulate less fat compared with WT mice. CR applied to AC 5 KO results in rapid decrease in body weight, metabolic deterioration, and death. These data suggest that despite restricted food intake in CR , but augmented food intake in AC 5 KO , the two models affect longevity and metabolism similarly. To determine shared molecular mechanisms, m RNA expression was examined genome‐wide for brain, heart, skeletal muscle, and liver. Significantly more genes were regulated commonly rather than oppositely in all the tissues in both models, indicating commonality between AC 5 KO and CR . Gene ontology analysis identified many significantly regulated, tissue‐specific pathways shared by the two models, including sensory perception in heart and brain, muscle function in skeletal muscle, and lipid metabolism in liver. Moreover, when comparing gene expression changes in the heart under stress, the glutathione regulatory pathway was consistently upregulated in the longevity models but downregulated with stress. In addition, AC 5 and CR shared changes in genes and proteins involved in the regulation of longevity and stress resistance, including S irt1, A po D , and olfactory receptors in both young‐ and intermediate‐age mice. Thus, the similarly regulated genes and pathways in AC 5 KO and CR mice, particularly related to the metabolic phenotype, suggest a unified theory for longevity and stress resistance.