Distribution of the Alpha-Synuclein in the Brain and the Primary Organs of the Rhesus Monkey

Previous studies have shown that abnormal aggregation of alpha-synuclein (alpha-syn) protein is a major trigger of neurodegenerative diseases. The expression level of alpha-syn in different brain regions and the disease-susceptible regions varies with the development of the disease. The expression pattern of the alpha-syn protein in mouse brain has been precisely described in the literature. Some studies have also reported the ubiquitous expression of the alpha-syn protein in the central and peripheral in nonhuman primates (NHPs). However, little is known about the expression pattern of alpha-syn in the brain or in the primary organs of NHPs. Here, we investigated the expression profile of alpha-syn in different brain regions and the primary organs of NHPs. The alpha-syn protein was mainly distributed in layers III and V of the cerebral cortex and the hippocampus. In addition, strong immunofluorescent signals were detected in the striatum and the substantia nigra, especially in the globus pallidus and the substantia nigra pars compacta, where the expression was significantly and particularly strong, compared with that in the cerebellum or the cortex. In the cerebellum, intense alpha-syn signal was observed in the molecular layer, where it was significantly higher than in the nucleus or the medulla. In the brain, the alpha-syn was always detected both in the cytoplasm and the synapses. Additionally, the alpha-syn was widely expressed in primary organs. The alpha-syn signal was higher in the liver and small intestine than in the spleen. Thus, the regions displaying the highest alpha-syn expression are also those affected during the progression of neurodegenerative diseases. These results may provide basic reference data for the study of multi-systemic mechanism of neurodegenerative diseases.

Automated summary

Research has shown that alpha-synuclein protein is widely expressed in different brain regions and primary organs of nonhuman primates. The areas with the highest expression of alpha-synuclein are also the regions affected during the progression of neurodegenerative diseases.