Signal relay in C. elegans: A tissue-perspective on coordinating organismal proteostasis and its impact on aging

As the global demographics shifts towards an increasingly aging population, understanding the effects and molecular mechanisms underlying aging becomes more and more important within biomedical research. A hallmark of aging is the progressive deterioration of protein homeostasis (proteostasis), characterized by the accumulation of misfolded protein aggregates within the cell. The proteostasis network is essential in mitigating the harmful effects of proteotoxic aggregates by activating stress response and degradation pathways. Significant discoveries in aging research are often inherently intertwined with proteostasis, many of which were made using the invertebrate Caenorhabditis elegans. Many longevity pathways, such as the insulin-like signaling pathway, initially identified in C. elegans, are mediated through inter-tissue stress signaling from the nervous system, intestine, or gonad. These cell nonautonomous signaling pathways not only enhance lifespan and stress resilience but also limit age-related accumulation of protein aggregates that exacerbate age-associated diseases. Thus, findings from aging research were often key to providing new insights into cell nonautonomous regulation of stress responses and organismal proteostasis. In this review, we outline key discoveries made using C. elegans as a model system and highlight their contributions that led to our current understanding of inter-tissue communication in organismal proteostasis regulation. We furthermore highlight emerging concepts and discuss the translational relevance of conserved cell nonautonomous proteostasis regulation in mammals. We emphasize the importance of mammalian research to support the research done in C. elegans, with the future goal of developing potential therapeutic interventions targeting these inter-tissue proteostasis signaling pathways to combat aging.