Insulin/insulin-like growth factor-1 signalling (IIS) based regulation of lifespan across species

An organism's well-being is facilitated by numerous molecular and biochemical pathways that ensure homeostasis within cells and tissues. Aging causes a gradual let-down in the maintenance of homeostasis due to various endogenous and environmental challenges, leading to amassing of damages, functional deterioration of different tissues and vulnerability to ailments. Nutrient sensing pathways that maintain glucose homeostasis in body are involved in regulation of aging. Insulin/insulin-like growth factor-1 (IGF-1) signalling (IIS) pathway was the first nutrient sensing pathway discovered to affect the aging process. This pathway is highly conserved and the most studied among different organisms. Epigenetic machineries that include DNA and histone modifying enzymes and various non-coding RNAs have been identified as important contributors to nutrition-related longevity and aging control. In this report, we present the homology and differences in IIS pathway of various organisms including worm, fly, rodent and human. We also discuss how epigenome remodelling, chromatin based strategies, small and long non-coding RNA are involved to regulate multiple steps of aging or age-related insulin homeostasis. Enhanced study of the role of IIS pathway and epigenetic mechanisms that regulate aging may facilitate progressive prevention and treatment of human age-related diseases.