PDF(Pubmed)
Abstract：
Caudo-rostral migration of pathological forms of α-synuclein from the gut to the brain is proposed as an early feature in Parkinson\'s disease pathogenesis, but the underlying mechanisms remain unknown. Intestinal epithelial enteroendocrine cells sense and respond to numerous luminal signals, including bacterial factors, and transmit this information to the brain via the enteric nervous system and vagus nerve. There is evidence that gut bacteria composition and their metabolites change in Parkinson\'s disease patients, and these alterations can trigger α-synuclein pathology in animal models of the disorder. Here, we investigated the effect of toll-like receptor and free fatty acid receptor agonists on the intracellular level of α-synuclein and its release using mouse secretin tumour cell line 1 enteroendocrine cells. Secretin tumour cell line 1 enteroendocrine cells were treated for 24 or 48 h with toll-like receptor agonists (toll-like receptor 4 selective lipopolysaccharide; toll-like receptor 2 selective Pam3CysSerLys4) and the free fatty acid receptor 2/3 agonists butyrate, propionate and acetate. The effect of selective receptor antagonists on the agonists\' effects after 24 hours was also investigated. The level of α-synuclein protein was measured in cell lysates and cell culture media by western blot and enzyme-linked immunosorbent assay. The level of α-synuclein and tumour necrosis factor messenger RNA was measured by quantitative reverse transcription real-time polymerase chain reaction. Stimulation of secretin tumour cell line 1 enteroendocrine cells for 24 and 48 hours with toll-like receptor and free fatty acid receptor agonists significantly increased the amount of intracellular α-synuclein and the release of α-synuclein from the cells into the culture medium. Both effects were significantly reduced by antagonists selective for each receptor. Toll-like receptor and free fatty acid receptor agonists also significantly increased tumour necrosis factor transcription, and this was effectively inhibited by corresponding antagonists. Elevated intracellular α-synuclein increases the likelihood of aggregation and conversion to toxic forms. Factors derived from bacteria induce α-synuclein accumulation in secretin tumour cell line 1 enteroendocrine cells. Here, we provide support for a mechanism by which exposure of enteroendocrine cells to specific bacterial factors found in Parkinson\'s disease gut dysbiosis might facilitate accumulation of α-synuclein pathology in the gut.
摘要：
α-突触核蛋白的病理形式从肠道向大脑的尾端迁移被认为是帕金森病发病机制的早期特征。但是潜在的机制仍然未知。肠上皮肠内分泌细胞感知并响应许多管腔信号，包括细菌因素,并通过肠神经系统和迷走神经将这些信息传递到大脑。有证据表明，帕金森病患者的肠道细菌组成及其代谢产物会发生变化，这些改变可以在该疾病的动物模型中引发α-突触核蛋白病理学。这里,我们使用小鼠促胰液素肿瘤细胞系1肠内分泌细胞研究了toll样受体和游离脂肪酸受体激动剂对细胞内α-突触核蛋白水平及其释放的影响。用Toll样受体激动剂（Toll样受体4选择性脂多糖；Toll样受体2选择性Pam3CysSerLys4）和游离脂肪酸受体2/3激动剂丁酸酯处理分泌素肿瘤细胞系1肠内分泌细胞24或48小时，丙酸盐和乙酸盐。还研究了24小时后选择性受体拮抗剂对激动剂作用的影响。通过蛋白质印迹和酶联免疫吸附测定在细胞裂解物和细胞培养基中测量α-突触核蛋白的水平。通过定量逆转录实时聚合酶链反应测量α-突触核蛋白和肿瘤坏死因子信使RNA的水平。用toll样受体和游离脂肪酸受体激动剂刺激促胰液素肿瘤细胞系1肠内分泌细胞24小时和48小时显著增加了细胞内α-突触核蛋白的量和α-突触核蛋白从细胞释放到培养基中。对每种受体具有选择性的拮抗剂显著降低了两种作用。Toll样受体和游离脂肪酸受体激动剂也显著增加肿瘤坏死因子的转录,这被相应的拮抗剂有效抑制。升高的细胞内α-突触核蛋白增加了聚集和转化为毒性形式的可能性。源自细菌的因子在促胰液素肿瘤细胞系1肠内分泌细胞中诱导α-突触核蛋白积累。这里,我们支持一种机制，通过这种机制，肠内分泌细胞暴露于帕金森病肠道菌群失调中发现的特定细菌因子可能促进肠道中α-突触核蛋白病理的积累。
