Double-stranded RNA (dsRNA) is a key molecule that initiates the immune response to viral infection, but increasingly endogenous (self) dsRNA has been found to be central to the pathology of diverse non-infectious diseases, from neurodegenerative disease to autoimmunity to cancers. Therefore, it is critical to understand the mechanisms that regulate endogenous dsRNA and the pattern recognition receptors that sense dsRNA.
In this dissertation, I address three main questions pertaining to this. First, why is the brain so prone to dsRNA-mediated non-infectious disease, especially considering that dsRNA sensors are expressed in almost all tissues. Using stem cell differentiation, gene expression manipulation, and microscopy, I determined that neurons are a special cell type that express high levels of endogenous dsRNA. This high dsRNA burden in neurons is driven by global lengthening of 3`untranslated regions (3`UTRs) and induces tonic inflammation.
Second, I examined the mechanism through which the dsRNA regulator ADAR1 controls endogenous dsRNA levels. I employed heavy use of tissue culture and visualization of dsRNA by confocal microscopy to determine that both the dsRNA-binding and dsRNA-editing activities of ADAR1 are required to suppress global endogenous dsRNA levels. Third, after identifying the existence of transcript isoforms of the key dsRNA sensor PKR, I explored their regulatory potential on the PKR protein itself. By genetically altering human cells, I identify that 3`UTR isoforms of PKR regulate transcript localization, translation efficiency, and PKR protein activatability. Overall, the studies described herein demonstrate novel regulatory roles of endogenous dsRNA and underscore the importance of dsRNA in neurological disease.
| Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/jy20-3k11 |
| Date | January 2024 |
| Creators | Dorrity, Tyler Johnathon |
| Source Sets | Columbia University |
| Language | English |
| Detected Language | English |
| Type | Theses |
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