Uneri Ayse, McArdle Colin J, Deng Zhiyong, Barth Samuel H, Keene Dirk, Craft Suzanne, Raab-Graham Kimberly F
Department of Translational Neuroscience, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA.
Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA.
J Alzheimers Dis. 2024 Dec;102(3):763-777. doi: 10.1177/13872877241291175. Epub 2024 Nov 29.
RNA-binding proteins (RBPs) modulate the synaptic proteome and are instrumental in maintaining synaptic homeostasis. Moreover, aberrant expression of an RBP in a disease state would have deleterious downstream effects on synaptic function. While many underlying mechanisms of synaptic dysfunction in Alzheimer's disease (AD) have been proposed, the contribution of RBPs has been relatively unexplored.
To investigate alterations in RBP-messenger RNA (mRNA) interactions in AD, and its overall impact on the disease-related proteome.
We first utilized RNA-immunoprecipitation to investigate interactions between RBP, DJ-1 (Parkinson's Disease protein 7) and target mRNAs in controls and AD. Surface Sensing of Translation - Proximity Ligation Assay (SUnSET-PLA) and western blotting additionally quantified alterations in mRNA translation and protein expression of DJ-1 targets. Finally, we utilized an unbiased bioinformatic approach that connects AD-related pathways to two RBPs, DJ-1 and FMRP (Fragile X messenger ribonucleoprotein 1).
We find that oligomeric DJ-1 in AD donor synapses were less dynamic in their ability to bind and unbind mRNA compared to synapses from cognitively unimpaired, neuropathologically-verified controls. Furthermore, we find that DJ-1 associates with the mRNA coding for FMRP, , leading to its reduced synaptic expression in AD. Through the construction of protein-protein interaction networks, aberrant expression of DJ-1 and FMRP are predicted to lead to the upregulation of key AD-related pathways, such as thyroid hormone stimulating pathway, autophagy, and ubiquitin mediated proteolysis.
DJ-1 and FMRP are novel targets that may restore established neurobiological mechanisms underlying AD.
RNA结合蛋白（RBPs）可调节突触蛋白质组，并在维持突触稳态中发挥作用。此外，疾病状态下RBP的异常表达会对突触功能产生有害的下游影响。虽然已经提出了许多阿尔茨海默病（AD）突触功能障碍的潜在机制，但RBPs的作用尚未得到充分研究。
研究AD中RBP与信使核糖核酸（mRNA）相互作用的变化及其对疾病相关蛋白质组的总体影响。
我们首先利用RNA免疫沉淀技术研究对照组和AD组中RBP、DJ-1（帕金森病蛋白7）与靶mRNA之间的相互作用。翻译表面传感-邻近连接分析（SUnSET-PLA）和蛋白质印迹法进一步量化了DJ-1靶标的mRNA翻译和蛋白质表达的变化。最后，我们采用了一种无偏倚的生物信息学方法，将AD相关通路与两种RBP，DJ-1和脆性X信使核糖核蛋白1（FMRP）联系起来。
我们发现，与认知未受损、经神经病理学验证的对照组突触相比，AD供体突触中的寡聚DJ-1结合和解离mRNA的能力变化较小。此外，我们发现DJ-1与编码FMRP的mRNA相关联，导致其在AD中的突触表达降低。通过构建蛋白质-蛋白质相互作用网络，预测DJ-1和FMRP的异常表达会导致关键AD相关通路的上调，如甲状腺激素刺激通路、自噬和泛素介导的蛋白水解。
DJ-1和FMRP是可能恢复AD潜在神经生物学机制的新靶点。
