Micro RNA-124 slows down the progression of Huntington's disease by promoting neurogenesis in the striatum

MicroRNA-124 contributes to neurogenesis through regulating its targets, but its expression both in the brain of Huntington＇s disease mouse models and patients is decreased. However, the effects of microRNA-124 on the progression of Huntington＇s disease have not been reported. Results from this study showed that microRNA-124 increased the latency to fall for each R6/2 Hunting- ton＇s disease transgenic mouse in the rotarod test. 5-Bromo-2＇-deoxyuridine （BrdU） staining of the striatum shows an increase in neurogenesis. In addition, brain-derived neurotrophic factor and peroxisome proliferator-activated receptor gamma coactivator 1-alpha protein levels in the striatum were increased and SRY-related HMG box transcription factor 9 protein level was de- creased. These findings suggest that microRNA-124 slows down the progression of Huntington＇s disease possibly through its important role in neuronal differentiation and survival.

Downregulated miR-18b-5p triggers apoptosis by inhibition of calcium signaling and neuronal cell differentiation in transgenic SOD1(G93A)mice and SOD1(G17S and G86S)ALS patients

Background:MicroRNAs(miRNAs)are endogenous non-coding RNAS that regulate gene expression at the post-transcriptional level and are key modulators in neurodegenerative diseases.Overexpressed miRNAs play an important role in amyotrophic lateral sclerosis(ALS);however,the pathogenic mechanisms of deregulated miRNAS are still unclear.Methods:We aimed to assess the dysfunction of RNAS or miRNAs in fALS(SOD1 mutations).We compared the RNA-seq of subcellular fractions in NSC-34 WT(hSOD1)and MT(hSOD1(G93A))cells to find altered RNAs or miRNAs.We identified that Hif1a and Mef2c were upregulated,and Mctp1 and Rarb were downregulated in the cytoplasm of NSC-34 MT cells.Results:SOD1 mutations decreased the level of miR-18b-5p.Induced Hif1a which is the target for miR-18b increased Mef2c expression as a transcription factor.Mef2c upregulated miR-206 as a transcription factor.Inhibition of Mctp1 and Rarb,which are targets of miR-206,induced intracellular Ca^2+ levels and reduced cell differentiation,respectively.The miR-18b-5p pathway was also observed in G93A Tg mice,fALS(G86S)patient,and iPSC-derived motor neurons from fALS(G17S)patient.Conclusions:Our data indicate that SOD1 mutation decreases miR-18b-5p,which sequentially regulates Hif1a,Mef2c,miR-206,Mctp1 and Rarb in fALS-linked SOD1 mutation.These results provide new insights into the downregulation of miR-18b-5p-dependent pathogenic mechanisms of ALS.