转录因子EB(TFEB)是参与自噬和溶酶体稳态维持的基因的主要调节因子,与GBA相关和散发性帕金森病(PD)发病机制有关的过程,和路易体痴呆(DLB)。TFEB活化导致其从胞质溶胶易位到细胞核。这里,我们研究了TFEB亚细胞定位及其与偶发路易体病(iLBD)个体死后人脑中细胞内α-突触核蛋白(aSyn)积累的关系,GBA相关PD/DLB(GBA-PD/DLB)或散发性PD/DLB(sPD/DLB),与对照组相比。我们使用高分辨率共聚焦和受激发射损耗(STED)显微镜分析了黑质多巴胺能神经元,并对TFEB亚细胞定位模式进行了半定量评分。与对照组相比,我们观察到PD/DLB患者的核TFEB免疫反应性降低,在零星和GBA相关病例中,以及在iLBD病例中。在所有组中具有Ser129磷酸化(pSer129)aSyn积累的神经元中,TFEB的核耗竭更为明显。重要的是,我们在人类多巴胺能神经元中观察到先前未发现的TFEB免疫阳性核周簇,位于高尔基体。这些TFEB簇在iLBD中更常见且更严重,sPD/DLB和GBA-PD/DLB与对照组相比,特别是在pSer129aSyn阳性神经元中,而且在缺乏可检测的aSyn积累的神经元中也是如此。在aSyn阴性细胞中,在GBA-PD/DLB和iLBD患者中更频繁地观察到细胞质TFEB簇,并与GBA酶活性降低以及BraakLB阶段增加相关。TFEB分布的改变伴随着所选TFEB调节基因的整体mRNA表达水平的降低,表明溶酶体调节可能的早期功能障碍。总的来说,我们在iLBD和PD/DLB患者中观察到胞浆TFEB在高尔基体的保留和积累,而没有明显的pSer129aSyn积累。这表明在细胞疾病的早期阶段有潜在的TFEB损伤,并强调TFEB是突触核蛋白病的有希望的治疗靶标。
Transcription factor EB (TFEB) is a master regulator of genes involved in the maintenance of autophagic and lysosomal homeostasis, processes which have been implicated in the pathogenesis of
GBA-related and sporadic Parkinson\'s disease (PD), and dementia with Lewy bodies (DLB). TFEB activation results in its translocation from the cytosol to the nucleus. Here, we investigated TFEB subcellular localization and its relation to intracellular alpha-synuclein (aSyn) accumulation in post-mortem human brain of individuals with either incidental Lewy body disease (iLBD), GBA-related PD/DLB (
GBA-PD/DLB) or sporadic PD/DLB (sPD/DLB), compared to control subjects. We analyzed nigral dopaminergic neurons using high-resolution confocal and stimulated emission depletion (STED) microscopy and semi-quantitatively scored the TFEB subcellular localization patterns. We observed reduced nuclear TFEB immunoreactivity in PD/DLB patients compared to controls, both in sporadic and GBA-related cases, as well as in iLBD cases. Nuclear depletion of TFEB was more pronounced in neurons with Ser129-phosphorylated (pSer129) aSyn accumulation in all groups. Importantly, we observed previously-unidentified TFEB-immunopositive perinuclear clusters in human dopaminergic neurons, which localized at the Golgi apparatus. These TFEB clusters were more frequently observed and more severe in iLBD, sPD/DLB and
GBA-PD/DLB compared to controls, particularly in pSer129 aSyn-positive neurons, but also in neurons lacking detectable aSyn accumulation. In aSyn-negative cells, cytoplasmic TFEB clusters were more frequently observed in
GBA-PD/DLB and iLBD patients, and correlated with reduced
GBA enzymatic activity as well as increased Braak LB stage. Altered TFEB distribution was accompanied by a reduction in overall mRNA expression levels of selected TFEB-regulated genes, indicating a possible early dysfunction of lysosomal regulation. Overall, we observed cytoplasmic TFEB retention and accumulation at the Golgi in cells without apparent pSer129 aSyn accumulation in iLBD and PD/DLB patients. This suggests potential TFEB impairment at the early stages of cellular disease and underscores TFEB as a promising therapeutic target for synucleinopathies.