Amyotrophic lateral sclerosis (ALS) is a progressive adult onset neurodegenerative disease characterized by selective death of the upper and lower motor neurons of the brain and spinal cord. Neuromuscular synapses are lost leading to paralysis and ultimately death. Non-neuronal cells, such as astrocytes, oligodendrocytes, and microglia, have been shown to contribute to ALS disease progression in mouse models. Microglia, the innate immune cells of the central nervous system, have been shown to be activated in ALS and contribute to disease progression. Hundreds of mRNAs have shown to be dysregulated in a variety of ALS cell types and tissues, including total spinal cord, acutely isolated microglia, and in vitro differentiated motor neurons. These mRNAs can be regulated post-transcriptionally by microRNAs (miRNAs), which are small endogenous non-coding RNAs with important regulatory roles in a wide range of cellular processes. This dissertation examines the contribution of miRNAs to ALS disease progression in microglia. I acutely isolated primary microglia from the spinal cords of transgenic mice overexpressing human wild type (WT) SOD1 and human G93A SOD1. I used small RNA sequencing to profile the miRNAs that are expressed during disease progression, and identified miRNAs that are differentially expressed. I confirmed these results by quantitative PCR and examined the expression changes of predicted targets in a microglia RNA-seq dataset. Here I show that miRNAs are dysregulated in acutely isolated microglia from SOD1 G93A transgenic mice, and that miR-155, a pro-inflammatory miRNA, and miR-210, a hypoxia-inducible miRNA, are significantly upregulated during disease progression. In addition, miR-1198-5p,
miR-182, miR-503, and miR-668 are also dysregulated, and predicted mRNA targets of all six of these miRNAs are differentially expressed during disease progression. To my knowledge, this is the first analysis of miRNA expression in microglia during ALS disease progression. This work contributes to the understanding of the contribution of a non-neuronal cell type to ALS disease progression and serves as a paradigm for studies in other non-neuronal cell types, such as astrocytes and oligodendrocytes, and other ALS mouse models.
| Identifer | oai:union.ndltd.org:harvard.edu/oai:dash.harvard.edu:1/9295166 |
| Date | 21 June 2014 |
| Creators | Morimoto, Emiko |
| Contributors | Maniatis, Thomas P., Melton, Douglas A. |
| Publisher | Harvard University |
| Source Sets | Harvard University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Rights | open |
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