Wang Bing, Gannon Mary, Pattanayak Rudradip, Scholz Kasandra, Pair Frank Sanders, Stone William J, Ekkatine Roschongporn, Liu Zhongyu, Yacoubian Talene A
Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America.
Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL 35294, United States of America.
Neurobiol Dis. 2025 Mar;206:106801. doi: 10.1016/j.nbd.2025.106801. Epub 2025 Jan 11.
Aggregation of alpha-synuclein (αsyn) plays an integral role in Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). 14-3-3θ is a highly expressed brain protein with chaperone-like activity that regulates αsyn folding. 14-3-3θ overexpression reduces αsyn aggregation, transmission between cells, and neuronal loss, while 14-3-3 inhibition promotes αsyn pathology. We previously observed increased 14-3-3θ phosphorylation at serine 232 in human PD and DLB brains. Here we examine 14-3-3θ phosphorylation's effects on αsyn aggregation and toxicity. Using a paracrine αsyn model, we found that the non-phosphorylatable S232A 14-3-3θ protected while the phosphomimetic S232D 14-3-3θ failed to protect against αsyn paracrine toxicity. The S232A mutant reduced oligomerization of released αsyn while the S232D mutant did not. The S232D mutant showed significant reduction in αsyn binding compared to wildtype or S232A 14-3-3θ. Using knock-in mouse models expressing the S232A or S232D mutation in the cortex and hippocampus, we examined the impact of S232 phosphorylation on αsyn aggregation in the αsyn preformed fibril (PFF) model. Primary neurons from S232D mice showed increased αsyn inclusion formation compared to neurons from Cre control mice upon PFF treatment. In contrast, neurons from S232A mice showed reduced αsyn inclusions. αSyn PFF injection into the dorsolateral striatum induced higher αsyn inclusion numbers in the sensorimotor cortex of S232D mice compared to Cre control mice. In conclusion, 14-3-3θ phosphorylation at S232 interrupts the ability of 14-3-3θ to bind and regulate αsyn aggregation. Increased 14-3-3θ phosphorylation observed in human PD and DLB likely accelerates neurodegeneration in these disorders.
α-突触核蛋白（αsyn）的聚集在帕金森病（PD）和路易体痴呆（DLB）中起着不可或缺的作用。14-3-3θ是一种在大脑中高表达的蛋白质，具有伴侣样活性，可调节αsyn的折叠。14-3-3θ的过表达可减少αsyn的聚集、细胞间传递以及神经元损失，而抑制14-3-3则会促进αsyn病理变化。我们之前观察到在人类PD和DLB大脑中，14-3-3θ在丝氨酸232处的磷酸化增加。在此，我们研究14-3-3θ磷酸化对αsyn聚集和毒性的影响。使用旁分泌αsyn模型，我们发现非磷酸化的S232A 14-3-3θ具有保护作用，而模拟磷酸化的S232D 14-3-3θ未能预防αsyn旁分泌毒性。S232A突变体减少了释放的αsyn低聚物的形成，而S232D突变体则没有。与野生型或S232A 14-3-3θ相比，S232D突变体显示出αsyn结合的显著减少。使用在皮层和海马中表达S232A或S232D突变的基因敲入小鼠模型，我们在αsyn预形成纤维（PFF）模型中研究了S232磷酸化对αsyn聚集的影响。与经PFF处理的Cre对照小鼠的神经元相比，来自S232D小鼠的原代神经元显示出αsyn包涵体形成增加。相反，来自S232A小鼠的神经元显示出αsyn包涵体减少。与Cre对照小鼠相比，向S232D小鼠的背外侧纹状体注射αsyn PFF在感觉运动皮层中诱导出更高的αsyn包涵体数量。总之，14-3-3θ在S232处的磷酸化中断了14-3-3θ结合和调节αsyn聚集的能力。在人类PD和DLB中观察到的14-3-3θ磷酸化增加可能会加速这些疾病中的神经退行性变。
