Research progress of cathepsin B in brain aging and Alzheimer's diseases.

Cathepsin B (CatB), a cysteine protease derived from lysosomes, was initially thought to non-selectively degrade proteins from phagocytosis and autophagy in lysosomes. However, CatB has been demonstrated to selectively degrade and specifically activate target proteins, thereby regulating the process of physiological and pathological responses. The expression, enzymatic activity, and cellular localization of CatB are significantly altered in brain aging and age-related neurodegenerative diseases. Therefore, the pathological function of CatB has attracted much attention in neuroscience research. In this review, we systematically summarize the molecular functions of CatB in brain aging and Alzheimer's disease and discuss the current problems in neuropathological studies of CatB, which lay a foundation for a comprehensive understanding of the pathogenesis of aging and Alzheimer's disease.