LAMP2A Upregulation to Enhance Chaperone-Mediated Autophagy for Tau Clearance in Alzheimer's Disease

Age-related decline in chaperone-mediated autophagy (CMA) contributes to the selective accumulation of hyperphosphorylated tau species in Alzheimer’s disease, particularly in cortical and hippocampal neurons where CMA dysfunction precedes amyloid pathology. This hypothesis proposes that targeted upregulation of LAMP2A (Lysosome Associated Membrane Protein 2A) can restore selective protein degradation capacity specifically for tau clearance in Alzheimer’s disease-affected neurons. LAMP2A serves as the rate-limiting component and sole lysosomal receptor for CMA, a highly selective autophagy pathway that recognizes proteins containing KFERQ-like motifs through HSC70 chaperone binding. During aging and neurodegeneration, LAMP2A expression declines while its degradation by lysosomal proteases increases, creating a bottleneck for CMA substrate translocation. By enhancing LAMP2A stability through cathepsin inhibition, promoting its transcriptional upregulation via retinoic acid receptor activation, or direct LAMP2A gene delivery, we can restore the lysosomal translocation complex that includes HSC70, HSP90, and LAMP2A multimers. This enhanced CMA capacity will selectively target monomeric and oligomeric tau species bearing CMA recognition motifs, preventing their aggregation into neurofibrillary tangles while preserving physiological tau functions. The intervention targets the earliest stages of tau pathology before fibril formation renders tau inaccessible to CMA degradation. Evidence will be gathered through stereotaxic delivery of LAMP2A vectors to hippocampi of P301S tau transgenic mice, measuring tau clearance kinetics using pulse-chase proteomics, CMA flux assays with fluorescent tau reporters, and cognitive assessments. Biomarker validation will track tau oligomer levels in cerebrospinal fluid and assess regional tau burden using tau-PET imaging in early-stage Alzheimer’s patients.