Decoding senescent drivers in Alzheimer's disease: From bench to bedside

Abstract

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated with dementia. Cellular senescence, widely acknowledged as a key hallmark of aging, has increasingly been recognized as a significant factor in the pathogenesis of AD, although the precise mechanisms underlying this relationship have yet to be fully understood. In the brains of individuals with AD, neurons, glial cells, and cerebrovascular endothelial cells exhibit premature senescence, characterized by irreversible cell cycle arrest, resistance to apoptosis, and the secretion of a diverse range of bioactive molecules collectively referred to as the senescence-associated secretory phenotype (SASP). These senescent cells profoundly influence the neural microenvironment through the release of SASP factors, thus exacerbating Aβ- and tau-induced neurotoxicity, promoting neuroinflammatory responses, and impairing the integrity of the blood-brain barrier (BBB), ultimately giving rise to a self-sustaining "senescence-neurodegeneration" cycle. Despite progress in therapies targeting Aβ and tau pathology, their clinical effectiveness remains limited, highlighting the urgent need for alternative therapeutic strategies. This review presents a comprehensive analysis of the molecular mechanisms connecting AD with cellular senescence, examines how the senescent microenvironment contributes to neurodegeneration, and evaluates the therapeutic potential of senotherapeutic interventions—including senolytics and senomorphics—as novel approaches for the clinical management of AD.