There is increasing evidence that Parkinson’s disease (PD) might start in the gut, thus involving and compromising also the enteric nervous system (ENS). At the clinical onset of the disease the majority of dopaminergic neurons in the midbrain is already destroyed, so that the lack of early biomarkers for the disease represents a major challenge for developing timely treatment interventions. Here, we use a transgenic A30P-α-synuclein-overexpressing PD mouse model to identify appropriate candidate markers in the gut before hallmark symptoms begin to manifest. Based on a gait analysis and striatal dopamine levels, we defined 2-month-old A30P mice as pre-symptomatic (psA30P), since they are not showing any motoric impairments of the skeletal neuromuscular system and no reduced dopamine levels, but an intestinal α-synuclein pathology. Mice at this particular age were further used to analyze functional and molecular alterations in both, the gastrointestinal tract and the ENS, to identify early pathological changes. We examined the gastrointestinal motility, the molecular composition of the ENS, as well as the expression of regulating miRNAs. Moreover, we applied A30P-α-synuclein challenges in vitro to simulate PD in the ENS. A retarded gut motility and early molecular dysregulations were found in the myenteric plexus of psA30P mice. We found that i.e. neurofilament light chain, vesicle-associated membrane protein 2 and calbindin 2, together with the miRNAs that regulate them, are significantly altered in the psA30P, thus representing potential biomarkers for early PD. Many of the dysregulated miRNAs found in the psA30P mice are reported to be changed in PD patients as well, either in blood, cerebrospinal fluid or brain tissue. Interestingly, the in vitro approaches delivered similar changes in the ENS cultures as seen in the transgenic animals, thus confirming the data from the mouse model. These findings provide an interesting and novel approach for the identification of appropriate biomarkers in men.

中文翻译：

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帕金森小鼠在运动疾病发作之前很久就表现出肠道功能和分子变化

越来越多的证据表明帕金森病 (PD) 可能始于肠道，因此也涉及并损害肠神经系统 (ENS)。在疾病临床发作时，中脑中的大多数多巴胺能神经元已经被破坏，因此缺乏该疾病的早期生物标志物对制定及时的治疗干预措施构成了重大挑战。在这里，我们使用转基因 A30P-α-突触核蛋白过表达 PD 小鼠模型，在标志性症状开始显现之前鉴定肠道中适当的候选标记。基于步态分析和纹状体多巴胺水平，我们将 2 个月大的 A30P 小鼠定义为症状前小鼠 (psA30P)，因为它们没有表现出任何骨骼神经肌肉系统运动障碍，也没有表现出多巴胺水平降低，但肠道 α -突触核蛋白病理学。该特定年龄的小鼠被进一步用于分析胃肠道和 ENS 的功能和分子变化，以识别早期病理变化。我们检查了胃肠运动、ENS 的分子组成以及调节 miRNA 的表达。此外，我们在体外应用 A30P-α-突触核蛋白挑战来模拟 ENS 中的 PD。在 psA30P 小鼠的肌间神经丛中发现了肠道运动迟缓和早期分子失调。我们发现，神经丝轻链、囊泡相关膜蛋白 2 和钙结合蛋白 2 以及调节它们的 miRNA 在 psA30P 中显着改变，因此代表了早期 PD 的潜在生物标志物。据报道，在 psA30P 小鼠中发现的许多失调的 miRNA 在 PD 患者中也发生了变化，无论是在血液、脑脊液还是脑组织中。有趣的是，体外方法在 ENS 培养物中产生了与转基因动物中相似的变化，从而证实了小鼠模型的数据。这些发现为识别男性适当的生物标志物提供了一种有趣且新颖的方法。