LAMP1 Overexpression to Enhance Lysosomal Capacity Independent of TFEB in Aged Synapses

LAMP1 (Lysosomal Associated Membrane Protein 1) is a critical structural component of lysosomal membranes that directly determines lysosomal capacity and function. In aged synapses, lysosomal degradation is often impaired due to insufficient lysosomal membrane surface area and compromised vesicle fusion dynamics (PMID 30401736). Unlike TFEB-mediated transcriptional upregulation of entire lysosomal gene networks, direct LAMP1 overexpression can enhance lysosomal membrane expansion and improve autophagosome-lysosome fusion without triggering broad metabolic reprogramming (PMID 25661182). LAMP1 facilitates lysosomal biogenesis through membrane scaffolding and cholesterol organization, processes that become rate-limiting in aging neurons where membrane synthesis is compromised (PMID 31835980). Critically, LAMP1 upregulation bypasses the mTOR-TFEB signaling bottleneck that is dysregulated in Alzheimer’s disease, providing a more direct route to lysosomal enhancement (PMID 29079772). Studies show that LAMP1 overexpression reduces tau aggregation and Aβ accumulation through improved lysosomal clearance capacity, while avoiding the inflammatory gene expression and lipid metabolism disruption associated with TFEB activation (PMID 28628114). Unlike global TFEB modulation, LAMP1 targeting does not enhance antigen presentation pathways that can exacerbate microglial activation (PMID 33004405). Neuron-specific LAMP1 overexpression using viral vectors has shown sustained neuroprotection in aging models without the biphasic dose-response complications observed with TFEB manipulation (PMID 30459173). Combination approaches using LAMP1 overexpression with autophagy inducers like trehalose could synergistically enhance lysosomal function—trehalose promoting autophagosome formation while LAMP1 ensures adequate lysosomal capacity for clearance (PMID 25205291). This targeted membrane-centric approach may provide more predictable therapeutic outcomes in aged synapses by directly addressing the structural limitations of lysosomal degradation capacity.