Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland.
Department of Microbiology, Biochemistry &Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health, Newark, NJ, USA.
J Alzheimers Dis. 2024;101(3):823-834. doi: 10.3233/JAD-240512.
Glyoxalase domain containing protein 4 (GLOD4), a protein of an unknown function, is associated with Alzheimer's disease (AD). Three GLOD4 isoforms are known. The mechanism underlying GLOD4's association with AD was unknown.
To assess GLOD4's role in the central nervous system by studying GLOD4 isoforms expression in human frontal cerebral cortical tissues from AD patients and in brains of Blmh-/-5xFAD mouse AD model of AD.
GLOD4 protein and mRNA were quantified in human and mouse brains by western blotting and RT-qPCR, respectively. Mouse brain amyloid-β (Aβ) was quantified by western blotting. Behavioral assessments of mice were performed by cognitive/neuromotor testing. Glod4 gene in mouse neuroblastoma N2a-APPswe cells was silenced by RNA interference and Glod4, Aβ precursor protein (Aβpp), Atg5, p62, and Lc3 proteins and mRNAs were quantified.
GLOD4 mRNA and protein isoforms were downregulated in cortical tissues from AD patients compared to non-AD controls. Glod4 mRNA was downregulated in brains of Blmh-/-5xFAD mice compared to Blmh+/+5xFAD sibling controls, but not in Blmh-/- mice without the 5xFAD transgene compared to Blmh+/+ sibling controls. The 5xFAD transgene downregulated Glod4 mRNA in Blmh-/- mice of both sexes and in Blmh+/+ males but not females. Attenuated Glod4 was associated with elevated Aβ and worsened memory/sensorimotor performance in Blmh-/-5xFAD mice. Glod4 depletion in N2a-APPswe cells upregulated AβPP, and downregulated autophagy-related Atg5, p62, and Lc3 genes.
These findings suggest that GLOD4 interacts with AβPP and the autophagy pathway, and that disruption of these interactions leads to Aβ accumulation and cognitive/neurosensory deficits.
糖氧还蛋白结构域蛋白 4（GLOD4）是一种功能未知的蛋白，与阿尔茨海默病（AD）有关。已知有三种 GLOD4 同工型。GLOD4 与 AD 相关的机制尚不清楚。
通过研究 AD 患者的人额皮质组织和 AD 模型 Blmh-/-5xFAD 小鼠脑中的 GLOD4 同工型表达，来评估 GLOD4 在中枢神经系统中的作用。
通过 Western blot 和 RT-qPCR 分别定量人脑中的 GLOD4 蛋白和 mRNA，用 Western blot 定量小鼠脑内的淀粉样-β（Aβ）。用认知/神经运动测试对小鼠进行行为评估。用 RNA 干扰沉默小鼠神经母细胞瘤 N2a-APPswe 细胞中的 Glod4 基因，并定量 Glod4、Aβ 前体蛋白（Aβpp）、Atg5、p62 和 Lc3 蛋白和 mRNAs。
与非 AD 对照相比，AD 患者皮质组织中的 GLOD4 mRNA 和蛋白同工型下调。与 Blmh+/+5xFAD 同窝对照相比，Blmh-/-5xFAD 小鼠脑中的 Glod4 mRNA 下调，但与无 5xFAD 转基因的 Blmh-/- 小鼠相比则没有下调，而后者与 Blmh+/+ 同窝对照相比则没有下调。5xFAD 转基因下调了两性 Blmh-/- 小鼠和雄性 Blmh+/+ 小鼠的 Glod4 mRNA，但对雌性没有影响。减弱的 Glod4 与 Blmh-/-5xFAD 小鼠中 Aβ 的增加和记忆/感觉运动表现的恶化有关。N2a-APPswe 细胞中的 Glod4 耗竭会上调 AβPP，并下调自噬相关的 Atg5、p62 和 Lc3 基因。
这些发现表明 GLOD4 与 AβPP 和自噬途径相互作用，这些相互作用的破坏导致 Aβ 的积累和认知/神经感觉缺陷。
