Dissertation
Lytic Cell Death Mechanisms in Human Respiratory Syncytial Virus-infected Macrophages
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005437
Handle:
https://hdl.handle.net/2376/119194
Abstract
Human respiratory syncytial virus (RSV) is a common cause of pneumonia in children and immunocompromised people worldwide with no effective vaccine or antiviral treatments to date. RSV-infected alveolar macrophages induce an exaggerated, pro-inflammatory pulmonary immune response that becomes counter-productive to viral clearance. Infected macrophages undergo cell lysis, releasing cellular components known as Danger Associated Molecular Patterns (DAMPs) into the extracellular space which recruit additional inflammatory cells and create a positive feedback loop of unregulated inflammation. Cell death mechanisms are either nonlytic (a physiologic, non-inflammatory type of cell death best characterized by the mechanism of apoptosis) or lytic (a pathologic type of cell death that elicits a potent pro-inflammatory response and is best characterized by the mechanisms of either pyroptosis or necroptosis). Lying within the spectrum of cell death is a process known as autophagy, a cellular organelle degradation and recycling process that can induce lytic or nonlytic cell death depending on the cell type and a variety of internal and external stimuli. All cell death mechanisms have specific molecular signatures that define each death pathway, and identification of which pathways are induced in RSV-infected macrophages provides valuable information for targeted immunotherapeutic drug development in RSV-associated lung disease. Quantitative assessment of lytic cell death is best determined by analyzing the amount of the cytosolic enzyme lactate dehydrogenase released into the surrounding extracellular fluid, a distinguishing feature of lytic forms of cell death. In these in vitro studies, differentiated THP-1 monocytes are used to replicate the response of infected alveolar macrophages. Cells are infected with RSV, subjected to single and tandem chemical inhibition of key molecular apoptotic, pyroptotic, necroptotic, and autophagic targets, and quantitatively assessed for lytic cell death using a lactate dehydrogenase assay on the supernatant. The results of these studies indicate that both pyroptosis and necroptosis are involved in lytic cell death in RSV-infected alveolar macrophages, and autophagy is a driver of lytic cell death during RSV infection. In addition, these studies highlight the extensive cross-talk between the mechanisms that may complicate the design of pharmacologic therapy for a specific pathway target.
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Details
- Title
- Lytic Cell Death Mechanisms in Human Respiratory Syncytial Virus-infected Macrophages
- Creators
- Lori Ellen Bedient
- Contributors
- Santanu Bose (Advisor)Joshua Ramsay (Committee Member)Anthony Nicola (Committee Member)Troy Bankhead (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Veterinary Medicine
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 52
- Identifiers
- 99900591957301842
- Language
- English
- Resource Type
- Dissertation