Senescence- and Immunity-Related Changes in the Central Nervous System: A Comprehensive Review

Senescence is a cellular state characterized by an irreversible halt in the cell cycle, accompanied by alterations in cell morphology, function, and secretion. Senescent cells release a plethora of inflammatory and growth factors, extracellular matrix proteins, and other bioactive substances, collectively known as the senescence-associated secretory phenotype (SASP). These excreted substances serve as crucial mediators of senescent tissues, while the secretion of SASP by senescent neurons and glial cells in the central nervous system modulates the activity of immune cells. Senescent immune cells also influence the physiological activities of various cells in the central nervous system. Further, the interaction between cellular senescence and immune regulation collectively affects the physiological and pathological processes of the central nervous system. Herein, we explore the role of senescence in the physiological and pathological processes underlying embryonic development, aging, degeneration, and injury of the central nervous system, through the immune response. Further, we elucidate the role of senescence in the physiological and pathological processes of the central nervous system, proposing a new theoretical foundation for treating central nervous system diseases.