Análise das alterações transcricionais envolvidas no processo neurodegenerativo provocadas por 6-hidroxidopamina (6-ohda)

Abstract

Parkinson's disease (PD) is the most common neurodegenerative disorder of movement which has precedence to function of the age. This disease is considered a multifactorial disorder caused by genetic mutations and environmental factors that influence disease progression. Most cases of idiopathic PD are sporadic and probably resulting from a combination of polygenic inheritance, environmental exposures and gene/environment interactions complex, causing neural dysfunction combined with slow aging. Despite decades of intensive studies, pathophysiological and molecular mechanisms of this disease are not yet fully understood, especially in animal models. However, molecular biology have led to significant advances in the understanding of the pathways involved in the degenerative process. This is due to the emergence of sequencing techniques and continuous improvement of algorithms and bioinformatics programs. Coupled to this, this study aimed to identify transcriptional changes related to micro RNAs noncoding (miRNAs) and Alternative Splicing in striatum of Rattus norvegicus Albinus submitted to Parkinsonian model induced by unilateral injection of 6-OHDA (6-hydroxydopamine). The analysis was made from two groups (n = 10): one sham group underwent the surgical stress and the second was made to the model of Parkinson's disease induced by 6-OHDA. From the confirmation of Parkinsonism through behavioral tests, it was extracted the RNA followed by sequencing of transcripts using the Ilumina Hi-Seq2000 platform. Analyses in silico were made by calculating the relative expression by FPKM (reads per kilobase transcripts per million mapped reads) that normalized genes found and measured the count obtained reads. From these data, the analysis of relative expression was made (FPKM relative) of miRNAs with qualitative differences and splicings variants of the BDNF gene (Brain Derived Neurotrophic Factor) which showed lower expression values than 0.25 and greater than 4. In the present study, we identified 62 miRNAs and 96,970 readings isoforms mapped in 6-OHDA and sham groups. Among the main findings obtained, it is suggested, the involvement of miRNAs, Mir6314 and Mir6333 in neurodegeneration mechanism induced by 6-OHDA. In addition, it was verified the transcript variants of BDNF gene and the expression level thereof. It was noticed that, regardless of the resulting protein product, the level of BDNF transcriptional expression can vary, and one of the factors that contribute to this difference are the noncoding regions such as 5 'UTR region, suggesting that miRNAs can work in this area. Therefore, these results represent innovative findings in the area of neurotranscriptomic, focusing to parkinsonian model induced by 6-OHDA.