Progressive supranuclear palsy (PSP) is a sporadic neurodegenerative tauopathy variably affecting brainstem and cortical structures, and characterized by tau inclusions in neurons and glia. The precise mechanism whereby these protein aggregates lead to cell death remains unclear. To investigate the contribution of these different cellular abnormalities to PSP pathogenesis, we performed single-nucleus RNA sequencing (snRNA-seq) and analyzed 50,708 high quality nuclei targeting the diencephalon, including the subthalamic nucleus and adjacent structures, from human post-mortem PSP brains with varying degrees of pathology compared to controls. Cell-type-specific differential expression and pathway analysis identified both common and discrete changes in numerous pathways previously implicated in PSP and other neurodegenerative disorders. This included EIF2 signaling, an adaptive pathway activated in response to diverse stressors, which was activated in multiple vulnerable cell types and validated in independent snRNA-seq and bulk RNA-seq datasets. Using immunohistochemistry, we found that activated eIF2α was positively correlated with tau pathology burden in vulnerable brain regions. Multiplex immunofluorescence localized activated eIF2α positivity to hyperphosphorylated tau (p-tau) positive neurons and ALDH1L1-positive astrocytes, supporting the increased transcriptomic EIF2 activation observed in these vulnerable cell types. In conclusion, these data provide insights into cell-type-specific pathological changes in PSP and support the hypothesis that failure of adaptive stress pathways play a mechanistic role in the pathogenesis and progression of PSP.

进行性核上性麻痹 （PSP） 是一种散发性神经退行性 tau 蛋白病，可不同程度地影响脑干和皮质结构，其特征是神经元和神经胶质细胞中有 tau 包涵体。这些蛋白质聚集体导致细胞死亡的确切机制尚不清楚。为了研究这些不同细胞异常对 PSP 发病机制的贡献，我们进行了单核 RNA 测序 （snRNA-seq） 并分析了 50,708 个靶向间脑的高质量细胞核，包括丘脑底核和邻近结构，来自人类死后 PSP 大脑与对照组相比具有不同程度的病理学。细胞类型特异性差异表达和通路分析确定了以前与 PSP 和其他神经退行性疾病相关的许多通路的常见和离散变化。这包括 EIF2 信号传导，这是一种响应不同压力源而激活的适应性通路，在多种脆弱的细胞类型中被激活，并在独立的 snRNA-seq 和批量 RNA-seq 数据集中得到验证。使用免疫组化，我们发现激活的 eIF2α 与脆弱脑区的 tau 病理负荷呈正相关。多重免疫荧光将激活的 eIF2α 阳性定位于过度磷酸化的 tau （p-tau） 阳性神经元和 ALDH1L1 阳性星形胶质细胞，支持在这些脆弱细胞类型中观察到的转录组 EIF2 激活增加。总之，这些数据提供了对 PSP 细胞类型特异性病理变化的见解，并支持适应性应激途径失败在 PSP 的发病机制和进展中起机械作用的假设。