Abstract



MicroRNAs (miRNAs) are small noncoding RNA gene products about 18- to 24-nt-long. Mainly they negatively regulate protein expression of specific mRNA by either translational inhibition or mRNAs degradation .Mature miRNAs are the results of successive processing of primary transcripts (pri-miRNAs)which are facilitated by two RNase III enzymes, Drosha and Dicer with a characteristic hairpin secondary structure. Reporting of the aberrant expressions of miRNAs have been done in respect to different human diseases mainly in concern with cancer viz lung cancer, brain cancer, chronic lymphocytic leukemia, neurodegenerative diseases etc.. It is well established fact that miRNAs defines the expression patterns of the tissue-specificity. Neurodegenerative disease states the physiological nature of the cell, expression of miR-29a, miR-29b-1 and miR-9 are found significantly down regulated in Alzheimer’s disease. Biopsies of tumor from Parkinson’s disease patients exposed association of miR-30b, miR-30c, and miR-26a. Phylogenetic analysis of miRNA of Alzheimer and Huntington diseases gives insight into evolutionary relationship and reveals regulation of Mir-22, Mir 29a, and mir-128-1 in both diseases. Mir-22 shows down-regulation in Parkinson disease and Alzheimer disease while mir-128-1 and mir-29a shows the difference in their regulation pattern .In Alzheimer disease mir-128-1 is up regulated while in Huntington disease it is down regulated. Mir-29a is up regulated in Huntington disease while in Alzheimer disease, it is down regulated. These findings illustrates the importance of miRNA research in Neurodegenerative diseases with reference to novel targets identification which can give a better lead in concern to protective or prophylective approaches.