The a-synuclein has been implicated in the pathophysiology of Parkinson’s disease (PD), because mutations in the alpha-synuclein gene cause autosomal-dominant hereditary PD and fibrillary aggregates of alpha-synuclein are the major component of Lewy bodies. Since presynaptic accumulation of a-synuclein aggregates may trigger synaptic dysfunction and degeneration, researchers at Boehringer Ingelheim Pharma GmbH have analyzed alterations in synaptosomal proteins in early symptomatic a-synuclein(A30P)-transgenic mice by two-dimensional differential gel electrophoresis. Moreover, they carried out microRNA expression profiling using LC Sciences’ microfluidic chips, as microRNA have recently been shown to regulate synaptic plasticity in rodents and to modulate polyglutamine-induced protein aggregation and neurodegeneration in flies. Differentially expressed proteins in a-synuclein(A30P)-transgenic mice point to alterations in mitochondrial function, actin dynamics, iron transport, and vesicle exocytosis, thus partially resembling findings in PD patients. Oxygen consumption of isolated brain mitochondria, however, was not reduced in mutant mice. Levels of several microRNA (miR-10a, -10b, -212, -132, -495) were significantly altered. One of them (miR-132) has been reported to be highly inducible by growth factors and to be a key regulator of neurite outgrowth. Moreover, miR-132-recognition sequences were detected in the mRNA transcripts of two differentially expressed proteins. MicroRNA may thus represent novel biomarkers for neuronal malfunction and potential therapeutic targets for human neurodegenerative diseases.

(A) Representative measurements of mitochondrial oxygen consumption (oxygen flux is shown in red on the right vertical axis; oxygen concentration is shown in blue). Mitochondria- enriched fractions were prepared from the mouse brainstem and administered into the Oxygraph-2k analytical chamber (mito). Basal respiration after adding malate/pyruvate (mal/pyr) did not significantly differ between a-synuclein(A30P)-transgenic mice (right panel) and wild-type animals (left panel). ADP stimulated state 3 respiration and FCCP triggered uncoupled respiration reflecting mitochondrial respiratory capacity were also unchanged. (B) Representative regions of microRNA chip images. The Cy3 and Cy5 intensity images are color-coded. Red signals indicate miRNA that are highly expressed in the mouse brainstem. In the Cy3/Cy5 ratio image the color is yellow when Cy3 (wild-type mouse microRNA) level is equal to Cy5 (mutant asynuclein- transgenic mouse microRNA) level. The color is green when Cy3 level is higher than Cy5 level. The color is red when Cy3 level is lower than Cy5 level.

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miRNA Microarray Service – LC Sciences provides a microRNA (miRNA) expression profiling service using microarrays based on our in-house developed µParaflo® technology platform. We have standard arrays for all mature miRNAs of all species available in the latest version of the miRBase database (Release 21, July 2014). Our service is comprehensive and includes sample labeling, array hybridization, image data processing and in-depth data analysis. Two-three weeks after receiving your total RNA samples, we’ll send you both the raw and fully analyzed data. [Learn more…]

Reference

Hildebrandt T, Lenter M, Mack M, Rist W, Schnack C, Gillardon F. (2008) MicroRNA and proteome expression profiling in early-symptomatic α-synuclein(A30P)-transgenic mice. Proteomics Clin Appl 2(5), 697-705. [abstract]