Science Note
New Mechanisms of Lysosomal Dysfunction in Neurons [Jan. 27, 2025]
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Lysosomal function in neurons is essential for maintaining cellular homeostasis and degradative capacity, and its impairment contributes to the pathology of Alzheimer’s disease and other neurodegenerative disorders. Therefore, identifying factors that disrupt lysosomal function is important for developing new therapeutic strategies. Recent studies show that oligodendrocyte precursor cells promote lysosomal exocytosis by contacting neuronal somata, and that disruption of this cell-to-cell interaction leads to loss of lysosomal homeostasis. In a separate study, an APOE4 driven lysosomal remodeling program was shown to impair lysosomal acidification through TMED5 accumulation and LGALS3BP depletion in neuronal models and human Alzheimer’s disease brains. Together, these findings indicate that neuronal lysosomal dysfunction is regulated by both intercellular interactions and neuron intrinsic programs, providing new insight into Alzheimer’s disease pathology. |
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1. Oligodendrocyte precursor cells facilitate neuronal lysosome release (Nature Communications, 2025) Summary: Oligodendrocyte precursor cells (OPCs) are a major population of glial cells that give rise to myelinating oligodendrocytes, and they contact neuronal somata to promote the exocytosis of neuronal lysosomes at these contact sites. Impairment of OPC–neuron contacts leads to lysosome accumulation, disrupted lipid metabolism, and increased neuronal senescence, suggesting that breakdown of OPC–neuron interactions may contribute to Alzheimer’s disease–related neurodegeneration. Highlighted technique: To directly detect neuronal lysosome exocytosis in real time, the authors added Alexa Fluor 647–conjugated anti-LAMP1 antibodies to the culture medium before live imaging. Primary neurons cultured alone or co-cultured with OPCs were imaged by confocal microscopy using fluorescent labeling of neurons, OPCs, and lysosomes, and Alexa647-positive puncta within neuronal somata were quantified and analyzed based on their distance from OPC contact sites. |
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Summary: This study establishes a previously unrecognized APOE4-driven lysosomal remodeling program in neurons that directly impairs lysosomal acidification and degradative capacity. Quantitative lysosomal proteomics identifies TMED5 accumulation and LGALS3BP depletion as key drivers of APOE4-associated lysosomal dysfunction, with these alterations conserved across neuronal models and human Alzheimer’s disease brains. Highlighted technique: To assess changes in lysosomal function in neurons, the authors quantified lysosomal acidity and proteolytic activity in APOE-expressing neuronal cells. Specifically, they measured lysosomal pH using LysoTracker staining and ratiometric OregonGreen–dextran imaging, and assessed lysosomal protease activity by measuring Cathepsin B activity. Recommended tools |
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Application Note (click to open/close)
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With existing reagents, it was difficult to determine whether lysosomal mass or their function (pH) fluctuated because the discussion was based on changes in the fluorescence brightness of a single dye. This kit contains pHLys Green, which is highly specific to lysosomes and shows pH-dependent changes in fluorescence, and pH-resistant LysoPrime Deep Red. Using these two dyes, lysosomal pH and volume of the same sample can be measured for a detailed analysis of lysosomal function.
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| Existing lysosomal pH detection reagents have issues with dye localization, pH sensitivity, and retention. pHLys Green is a dye that solves these issues. The improved dye retention and localization enable detection of normal lysosomes, and the improved pH sensitivity enables detection of slight pH changes. | |||
| 1. High sensitive pH detection Comparison of pH response of cells treated with low concentrations of lysosomal acidification inhibitor Bafilomycin A1 |
2. High specificity for lysosomes Comparison of specificity for lysosomes using lysosomal marker protein LAMP1-GFP expressing cells |
3. High retention in lysosomes Comparison of intracellular retention |
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Lysosomes are essential for maintaining cell homeostasis by degrading and recycling biomolecules, regulating organelle quality control, and facilitating intracellular signaling. Lysosomal function is closely linked to the Golgi apparatus, endoplasmic reticulum, mitochondria, and nucleus, coordinating cellular metabolism and stress responses. When lysosomal function is impaired, damaged proteins and organelles accumulate, metabolic processes are disrupted, and cell membrane integrity is compromised, leading to various diseases. For example, in neurodegenerative diseases, lysosomal dysfunction leads to the accumulation of toxic aggregates, resulting in neuronal damage and cognitive decline. Understanding lysosomal regulation and its interactions with other organelles is critical for developing therapies to slow disease progression and promote cellular longevity.









