Emerging evidence suggests that some of the earliest events contributing to neurodegeneration may occur upstream of classical proteinopathies, underscoring the urgency of identifying molecular pathways that link age-associated genomic instability to chronic neuroinflammation. Among these, DNA sensing through the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) axis has emerged as an important mechanism by which nuclear and mitochondrial stress may promote innate immune activation. In aging and Alzheimer's disease (AD), oxidative stress, impaired DNA repair, and mitochondrial dysfunction can lead to the accumulation of cytosolic DNA and activation of cGAS-STING, contributing to sustained inflammatory signaling, cellular senescence, and synaptic dysfunction. In this review, we synthesize emerging mechanistic and translational insights linking cGAS-STING to genomic instability and neuroinflammation. We highlight the expanding roles of this pathway beyond classical immunity, including its influence on autophagy, cellular senescence, microglial activation, and neurovascular integrity as well as its interactions with key pathological features of age-related neurodegenerative disorders, particularly AD. Finally, we highlight recent advances in pharmacological and genetic modulation of cGAS-STING that support its potential as a therapeutic target for age-related neurodegenerative diseases. By reframing neurodegeneration through the lens of DNA sensing, this review provides an updated perspective on the potential role of cGAS-STING in age-related neurodegenerative diseases.
