Differential Regulation of Tau Exon 2 and 10 Isoforms in Huntington's Disease Brain.

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expansion of CAG repeats in the Huntingtin (HTT) gene. Accumulating evidence suggests that the microtubule-associated tau protein participates in the pathogenesis of HD. Recently, we have identified changes in tau alternative splicing of exons 2, 3 and 10 in the putamen of HD patients (St-Amour et al, 2018). In this study, we sought to determine whether tau mis-splicing events were equally observed in other brain regions that are less prone to neurodegeneration. Using Western blot and PCR, we characterized the relationship between MAPT splicing of exons 2, 3 and 10, tauopathy and Htt pathologies, as well as neurodegeneration markers in matching putamen and cortical samples from HD (N = 48) and healthy control (N = 25) subjects. We first show that levels of 4R-tau (exon 10 inclusion) isoforms are higher in both the putamen and the cortex of individuals with HD, consistent with earlier findings. On the other hand, higher 0N-tau (exclusion of exons 2 and 3) and lower 1N-tau (exclusion of exon 3) isoforms were seen exclusively in the putamen of HD individuals. Interestingly, investigated splicing factors were deregulated in both regions whereas exon 2 differences coincided with increased tau hyperphosphorylation, aggregation and markers of neurodegeneration. Overall, these results imply a differential regulation of tau exon 2 and exon 10 alternative splicing in HD putamen that could provide a useful biomarker or therapeutic target.

Widespread alterations in microRNA biogenesis in human Huntington's disease putamen.

Altered microRNA (miRNA) expression is a common feature of Huntington's disease (HD) and could participate in disease onset and progression. However, little is known about the underlying causes of miRNA disruption in HD. We and others have previously shown that mutant Huntingtin binds to Ago2, a central component of miRNA biogenesis, and disrupts mature miRNA levels. In this study, we sought to determine if miRNA maturation per se was compromised in HD. Towards this end, we characterized major miRNA biogenesis pathway components and miRNA maturation products (pri-miRNA, pre-miRNA, and mature) in human HD (N = 41, Vonsattel grades HD2-4) and healthy control (N = 25) subjects. Notably, the striatum (putamen) and cortex (BA39) from the same individuals were analyzed in parallel. We show that Ago2, Drosha, and Dicer were strongly downregulated in human HD at the early stages of the disease. Using a panel of HD-related miRNAs (miR-10b, miR-196b, miR-132, miR-212, miR-127, miR-128), we uncovered various types of maturation defects in the HD brain, the most prominent occurring at the pre-miRNA to mature miRNA maturation step. Consistent with earlier findings, we provide evidence that alterations in autophagy could participate in miRNA maturation defects. Notably, most changes occurred in the striatum, which is more prone to HTT aggregation and neurodegeneration. Likewise, we observed no significant alterations in miRNA biogenesis in human HD cortex and blood, strengthening tissue-specific effects. Overall, these data provide important clues into the underlying mechanisms behind miRNA alterations in HD-susceptible tissues. Further investigations are now required to understand the biological, diagnostic, and therapeutic implications of miRNA/RNAi biogenesis defects in HD and related neurodegenerative disorders.

miR-574, miR-499, miR-125b, miR-106a, and miR-9 potentially target TGFBR-1 and TGFBR-2 genes involving in inflammatory response pathway: Potential novel biomarkers for chronic lymphocytic leukemia.

MicroARNAs (miRNAs) are linked to a variety of cancers, which resulted in molecular pathway dysregulation in chronic lymphocytic leukemia (CLL). Using five dysregulated miRNAs identified by literature mining and in silico analysis, we were able to demonstrate the critical role that the TGFBR1 and TGFB receptor signaling pathways play in the state of CLL. Assays using real-time PCR were run on 30 patients and 30 healthy controls. This study showed that patient samples have considerably higher levels of miR-574 and miR-499. Notably, the same groups had lower expression levels of miR-125b, miR-106a, and miR-9. Furthermore, we suggested that TGFBR1 and TGFBR2 expression levels were decreased in patients, and we suggested that these genes could be targets for our profile miRNAs. In the current study, we hypothesized that miR-574, miR-499, miR-125b, miR-106a, and miR-9 are likely five new potential biomarkers for early diagnosis. Our research also showed that these profile miRNAs have a role in the formation of CLL, possibly through controlling the TGFBR1 and TGFBR2 pathways. This suggests that these profile miRNAs could serve as biomarkers for the diagnosis and prognosis of CLL.

Study of The Correlation between miR-106a, miR-125b, and miR-330 on Multiple Sclerosis Patients by Targeting TNFSF4 and SP1 in NF-кb/TNF-α Pathway: A Case-Control Study.

OBJECTIVE: Multiple sclerosis (MS) is a complex multifactorial neuro-inflammatory disorder. This complexity arises from the evidence suggesting that MS is developed by interacting with environmental and genetic factors. This study aimed to evaluate the miR-106a, miR-125b, and miR330- expression levels in relapsing-remitting multiple sclerosis (RRMS) patients. The miRNAs' impact on TNFSF4 and Sp1 genes through the NF-кB/TNF-α signaling pathway was analyzed by measuring the expression levels in case and controls. MATERIALS AND METHODS: In this in silico-experimental study, we evaluated the association of miR-106a, miR- 125b, and miR330- with TNFSF4 and SP1 gene expression levels in 60 RRMS patients and 30 healthy controls by real-time polymerase chain reaction (PCR). RESULTS: The expression levels of miR-330, miR-106a, and miR125-b in blood samples of RRMS patients were predominantly reduced. The expression of TNFSF4 in patients demonstrated a significant enhancement, in contrast to the diminishing Sp1 gene expression level in controls. CONCLUSION: Our findings indicated an association between miR-106a and miR-330 and miR125-b expression and RRMS in our study population. Our data suggested that the miR106-a, miR125-b, and mir330- expression are correlated with TNFSF4 and Sp1 gene expression levels.