Augur Zachary M, Fogo Garrett M, Arbery Mason R, Stern Andrew M, Benoit Courtney R, Hsieh Yi-Chen, Young-Pearse Tracy L
Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, 60 Fenwood Rd, Boston, MA, 02115, USA.
Acta Neuropathol Commun. 2025 Sep 2;13(1):188. doi: 10.1186/s40478-025-02103-y.
Optineurin (OPTN) is an autophagy adaptor protein involved in selective autophagy, including aggrephagy and mitophagy. Pathogenic mutations in OPTN have also been linked to amyotrophic lateral sclerosis, frontotemporal dementia, and glaucoma, supporting its role in the etiology of neurodegenerative diseases. Despite its established biological roles, knowledge about its potential contribution to Alzheimer's disease (AD) pathology and neuronal functioning is lacking. AD is characterized by the accumulation of extracellular amyloid-β plaques and intracellular phosphorylated tau (pTau) tangles, with dysfunction in the autophagy-lysosomal pathway exacerbating tau pathology and impairing proteostasis. To investigate the role of OPTN in neuronal proteostasis and AD, we utilized induced pluripotent stem cell-derived neuron (iN) and astrocyte (iA) models. Analyses revealed a significant negative correlation between OPTN and specific pTau epitopes in neurons, as well as a decrease in OPTN protein abundance in brain tissues of individuals with AD. Given these findings, we generated OPTN knockout (KO), heterozygous, and wildtype iNs and iAs using CRISPR/Cas9 editing of iPSCs in two genetic backgrounds. Loss of OPTN in iNs increased specific pTau proteoforms without substantially affecting autophagy processes or mitochondrial respiration. Despite no clear effect on mitochondrial function, several mitochondrial proteins, including OXCT1, were enriched in an unbiased analysis of the OPTN interactome in iNs, as well as proteins involved in intracellular trafficking. Proteomic analyses further identified intracellular clusterin, an AD risk gene, as significantly upregulated in OPTN KO iNs, suggesting OPTN may influence its intracellular processing. Our model system demonstrates modest roles for OPTN in certain neuronal biological processes and potential implications for AD pathogenesis. These findings also suggest that OPTN may exhibit functional redundancy with other autophagy adaptor proteins in human neurons, leading to relatively mild phenotypic changes with complete loss of OPTN.
视神经萎缩蛋白（OPTN）是一种自噬衔接蛋白，参与选择性自噬，包括聚集体自噬和线粒体自噬。OPTN的致病突变也与肌萎缩侧索硬化症、额颞叶痴呆和青光眼有关，这支持了其在神经退行性疾病病因学中的作用。尽管其生物学作用已得到确立，但关于其对阿尔茨海默病（AD）病理和神经元功能的潜在贡献的了解仍很缺乏。AD的特征是细胞外淀粉样β斑块和细胞内磷酸化tau（pTau）缠结的积累，自噬-溶酶体途径功能障碍会加剧tau病理并损害蛋白质稳态。为了研究OPTN在神经元蛋白质稳态和AD中的作用，我们利用了诱导多能干细胞衍生的神经元（iN）和星形胶质细胞（iA）模型。分析显示，OPTN与神经元中特定的pTau表位之间存在显著的负相关，以及AD患者脑组织中OPTN蛋白丰度的降低。鉴于这些发现，我们在两种遗传背景下使用CRISPR/Cas9编辑iPSC生成了OPTN基因敲除（KO）、杂合和野生型iN和iA。iN中OPTN的缺失增加了特定的pTau蛋白亚型，但对自噬过程或线粒体呼吸没有实质性影响。尽管对线粒体功能没有明显影响，但在对iN中OPTN相互作用组的无偏分析中，包括OXCT1在内的几种线粒体蛋白以及参与细胞内运输的蛋白都得到了富集。蛋白质组学分析进一步确定，AD风险基因细胞内簇蛋白在OPTN KO iN中显著上调，这表明OPTN可能影响其细胞内加工。我们的模型系统证明了OPTN在某些神经元生物学过程中的适度作用以及对AD发病机制的潜在影响。这些发现还表明，OPTN可能与人类神经元中的其他自噬衔接蛋白表现出功能冗余，导致OPTN完全缺失时出现相对较轻的表型变化。
