G Protein-Coupled Receptors as Targets to Slow Aging
Researchers here propose that greater efforts should be devoted to considering the variety of G-protein coupled receptors (GPCRs) as a regulatory network in the matter of aging and age-related disease. Aging produces sweeping changes in protein levels, gene expression, protein function and interactions, and one can thus make similar arguments for many different classes of molecule found in cells. The question is always whether one can justify intervention in a given mechanism on the basis of its importance to aging: where does it sit in the interacting network of cause and consequence? Is it causing a great deal of downstream harm, or is it more of an end stage consequence? How close is it to root causes of aging? This is a lot harder to answer than whether or not a mechanism has a role at all, but it is the crux of the matter, determining whether targeting that mechanism is a good choice or not.
G protein-coupled receptors (GPCRs) are arguably the most important class of signal transducers discovered to date. GPCRs are heptahelical transmembrane proteins that mediate responses to, among others, hormones, neurotransmitters, steroids, and immune modulators, many of which undergo dysregulation with age. GPCRs efficiently modulate a wide variety of signaling processes that underpin nearly all the mechanisms responsible for chronic age-related disease. Given their vital physiological role, dysfunction of GPCR signaling networks may represent a potential driver of aging pathophysiology. For example, age-related alterations in GPCR signaling contribute to chronic, low-grade inflammation (inflammaging), as seen in the increased activity of chemokine and cytokine receptors that results in immune system dysfunction. Additionally, GPCRs involved in metabolic regulation, such as adrenergic and insulin-sensitizing receptors, become less responsive with age, exacerbating metabolic disorders and insulin resistance. Mitochondrial dysfunction, another profound hallmark of aging, is also influenced by GPCR signaling through pathways that regulate oxidative stress and cellular energy homeostasis.
Therefore, GPCRs represent promising new therapeutic targets for mitigating - at both tissue-specific and systemic levels - age-associated diseases, which could work toward extending a person's healthspan. We posit that, while many diseases possess a specific genomic basis in their later stages, they may share a common feature in their genesis: the loss of cellular homeostasis. In this article, we evaluate the "GPCR-ome" as a central, "mega-trophic" regulator of human healthspan. We begin by examining the structural and functional vulnerabilities across major GPCR classes that render them susceptible to age-dependent decline. We then detail how these receptors functionally integrate with the fundamental hallmarks of aging (e.g., inflammaging, mitochondrial failure, and cellular senescence) to drive multisystemic disease. Finally, we propose a transformative therapeutic framework to transition from treating individual symptoms to targeting aging itself as a manageable, tunable process.