Altered machinery of protein synthesis is region- and stage-dependent and is associated with α-synuclein oligomers in Parkinson's disease.
Altered machinery of protein synthesis is region- and stage-dependent and is associated with α-synuclein oligomers in Parkinson's disease.
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DOI：
10.1186/s40478-015-0257-4
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发表时间：
2015-12-01
影响因子：
7.1
通讯作者：
Ferrer I
中科院分区：
文献类型：
--
作者：
Garcia-Esparcia P;Hernández-Ortega K;Koneti A;Gil L;Delgado-Morales R;Castaño E;Carmona M;Ferrer I
帕金森病（PD）的特征是异常α-突触核蛋白在大脑特定区域的积累，随着疾病的进展，其严重程度呈梯度。这是否伴随着全球蛋白质合成的改变，文献记载很少。本研究是在Braak和中年（MA）个体的PD 1-6期进行的，在大脑的黑质、额叶皮质区8、角回、楔前叶和壳核没有改变。核仁蛋白nucleolin （NCL）、核磷蛋白（NPM1）、核溶酶3 （NPM3）和上游结合转录因子（UBF） mRNA表达降低，NPM1免疫染色降低，NPM3免疫染色不降低；18S rRNA、28S rRNA减少；编码核糖体蛋白（RP）亚基的mrna表达减少；PD患者黑质中蛋白合成起始因子eIF3和延伸因子eEF2的蛋白水平随着疾病进展而改变。虽然这些变化中的许多可能与黑质神经元的丢失有关，但某些因素的选择性改变表明，退化的黑质中mrna、rRNAs和蛋白质的易损性程度是不同的。5 ~ 6期额叶皮质8区NPM1 mRNA和18S rRNA表达增加；角回和楔前叶的变化不太明显，且与区域相关。在PD中，额叶皮质8区和楔前叶区有几个RP异常调节，而角回区只有一个RP异常调节。PD患者额叶皮层eIF3和eIF1蛋白水平改变，eEF1A和eEF2蛋白水平降低。在研究的任何时候，壳核中都没有发现任何修饰，除了28S rRNA的短暂修饰和5-6期只有一个RP mRNA的修饰。这些观察结果进一步表明，PD患者的大脑皮层存在明显的区域依赖性和阶段依赖性改变。用抗α-突触核蛋白寡聚物特异性抗体印迹的总匀浆分数评估，PD患者的黑质和额叶皮层出现了溶解度和α-突触核蛋白寡聚物形成的改变，但壳核没有。在PD患者额叶皮层荧光活化细胞分选器（FACS）分离的核中α-突触核蛋白寡聚物也显著增加。PD患者的黑质和大脑皮层的蛋白质合成机制发生改变，其中额叶皮质区8比角回和楔前叶受影响更大；相反，蛋白质合成的途径显然保存在壳核中。这与总匀浆中α-突触核蛋白寡聚物的存在有关；α-突触核蛋白低聚物在黑质和额叶皮层中富集，但带型不同，而在壳核中未发现α-突触核蛋白低聚物。本文的在线版本（doi:10.1186/s40478-015-0257-4）包含补充材料，可供授权用户使用。
Parkinson’s disease (PD) is characterized by the accumulation of abnormal α-synuclein in selected regions of the brain following a gradient of severity with disease progression. Whether this is accompanied by globally altered protein synthesis is poorly documented. The present study was carried out in PD stages 1-6 of Braak and middle-aged (MA) individuals without alterations in brain in the substantia nigra, frontal cortex area 8, angular gyrus, precuneus and putamen. Reduced mRNA expression of nucleolar proteins nucleolin (NCL), nucleophosmin (NPM1), nucleoplasmin 3 (NPM3) and upstream binding transcription factor (UBF), decreased NPM1 but not NPM3 nucleolar protein immunostaining in remaining neurons; diminished 18S rRNA, 28S rRNA; reduced expression of several mRNAs encoding ribosomal protein (RP) subunits; and altered protein levels of initiation factor eIF3 and elongation factor eEF2 of protein synthesis was found in the substantia nigra in PD along with disease progression. Although many of these changes can be related to neuron loss in the substantia nigra, selective alteration of certain factors indicates variable degree of vulnerability of mRNAs, rRNAs and proteins in degenerating sustantia nigra. NPM1 mRNA and 18S rRNA was increased in the frontal cortex area 8 at stage 5-6; modifications were less marked and region-dependent in the angular gyrus and precuneus. Several RPs were abnormally regulated in the frontal cortex area 8 and precuneus, but only one RP in the angular gyrus, in PD. Altered levels of eIF3 and eIF1, and decrease eEF1A and eEF2 protein levels were observed in the frontal cortex in PD. No modifications were found in the putamen at any time of the study except transient modifications in 28S rRNA and only one RP mRNA at stages 5-6. These observations further indicate marked region-dependent and stage-dependent alterations in the cerebral cortex in PD. Altered solubility and α-synuclein oligomer formation, assessed in total homogenate fractions blotted with anti-α-synuclein oligomer-specific antibody, was demonstrated in the substantia nigra and frontal cortex, but not in the putamen, in PD. Dramatic increase in α-synuclein oligomers was also seen in fluorescent-activated cell sorter (FACS)-isolated nuclei in the frontal cortex in PD. Altered machinery of protein synthesis is altered in the substantia nigra and cerebral cortex in PD being the frontal cortex area 8 more affected than the angular gyrus and precuneus; in contrast, pathways of protein synthesis are apparently preserved in the putamen. This is associated with the presence of α-synuclein oligomeric species in total homogenates; substantia nigra and frontal cortex are enriched, albeit with different band patterns, in α-synuclein oligomeric species, whereas α-synuclein oligomers are not detected in the putamen. The online version of this article (doi:10.1186/s40478-015-0257-4) contains supplementary material, which is available to authorized users.