Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CiberNed), National Institute of Health Carlos III, 28029 Madrid, Spain.
Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, 08028 Barcelona, Spain.
Cells. 2023 Jan 11;12(2):283. doi: 10.3390/cells12020283.
The N-methyl-D-aspartate receptor (NMDAR) is a target in current treatments for Alzheimer's disease (AD). The human prion protein (PrPC) has an important role in the pathophysiology of AD. We hypothesized that PrPC modulates NMDA signaling, thus being a process associated with Alzheimer's disease.
NMDAR signaling was characterized in the absence or presence of PrPC in cAMP level determination, mitogen-activated protein kinase (MAPK) pathway and label-free assays in homologous and heterologous systems. Bioluminescence resonance energy transfer was used to detect the formation of NMDAR-PrPC complexes. AXIS™ Axon Isolation Devices were used to determine axonal transport of Tau and pTau proteins in cortical primary neurons in the absence or presence of PrPC. Finally, proximity ligation assays were used to quantify NMDA-PrPC complex formation in neuronal primary cultures isolated from APP transgenic mice, an Alzheimer's disease model expressing the Indiana and Swedish mutated version of the human amyloid precursor protein (APP).
We discovered a direct interaction between the PrPC and the NMDAR and we found a negative modulation of NMDAR-mediated signaling due to the NMDAR-PrPC interaction. In mice primary neurons, we identified NMDA-PrPC complexes where PrPC was capable of blocking NMDAR-mediated effects. In addition, we observed how the presence of PrPC results in increased neurotoxicity and neuronal death. Similarly, in microglial primary cultures, we observed that PrPC caused a blockade of the NMDA receptor link to the MAPK signaling cascade. Interestingly, a significant increase in NMDA-PrPC macromolecular complexes was observed in cortical neurons isolated from the APP transgenic model of AD.
PrPC can interact with the NMDAR, and the interaction results in the alteration of the receptor functionality. NMDAR-PrPC complexes are overexpressed in neurons of APP mouse brain. In addition, PrPC exacerbates axonal transport of Tau and pTau proteins.
N-甲基-D-天冬氨酸受体（NMDAR）是当前阿尔茨海默病（AD）治疗的靶点。人类朊蛋白（PrPC）在 AD 的病理生理学中具有重要作用。我们假设 PrPC 调节 NMDA 信号转导，因此是与阿尔茨海默病相关的过程。
在有无 PrPC 的情况下，通过 cAMP 水平测定、丝裂原活化蛋白激酶（MAPK）途径和同源和异源系统中的无标记测定来表征 NMDAR 信号转导。使用生物发光共振能量转移来检测 NMDAR-PrPC 复合物的形成。使用 AXIS™Axon Isolation Devices 在有无 PrPC 的情况下确定皮质原代神经元中 Tau 和 pTau 蛋白的轴突运输。最后，使用邻近连接测定来定量来自 APP 转基因小鼠（表达人淀粉样前体蛋白的印第安纳和瑞典突变版本的阿尔茨海默病模型）的神经元原代培养物中 NMDA-PrPC 复合物的形成。
我们发现 PrPC 与 NMDAR 之间存在直接相互作用，并且由于 NMDAR-PrPC 相互作用，发现了对 NMDAR 介导的信号转导的负调节。在小鼠原代神经元中，我们鉴定了能够阻断 NMDAR 介导的效应的 NMDA-PrPC 复合物。此外，我们观察到 PrPC 的存在如何导致神经毒性和神经元死亡增加。同样，在原代小胶质细胞培养物中，我们观察到 PrPC 导致 NMDA 受体与 MAPK 信号级联的连接受阻。有趣的是，在从 AD 的 APP 转基因模型分离的皮质神经元中观察到 NMDA-PrPC 大分子复合物的显著增加。
PrPC 可以与 NMDAR 相互作用，并且相互作用导致受体功能的改变。NMDAR-PrPC 复合物在 AD 的 APP 小鼠大脑的神经元中过度表达。此外，PrPC 加剧了 Tau 和 pTau 蛋白的轴突运输。
