Influenza A virus modulates the severity of relapsing-experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis

Soto-Diaz, Katiria

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https://hdl.handle.net/2142/117561 Copy

Description

Title

Influenza A virus modulates the severity of relapsing-experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis

Author(s)

Soto-Diaz, Katiria

Issue Date

2022-12-01

Director of Research (if dissertation) or Advisor (if thesis)

Steelman, Andrew J

Doctoral Committee Chair(s)

Steelman, Andrew J

Committee Member(s)

• Llano, Daniel A
• Inoue, Makoto
• Johnson, Rodney W

Department of Study

Neuroscience Program

Discipline

Neuroscience

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

multiple sclerosis, EAE, infection, influenza A virus, relapses, neuroinflammation

Abstract

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS) that affects young people. Disease is typically presented in a relapsing-remitting form, where the majority of persons with MS (pwMS) experience periods of loss of function that are interspersed by periods of disease remission. In some instances, pwMS can experience worsening of symptoms, known as relapses. Importantly, number of relapses can be used as a predictor of poor disease outcome and a faster transition to a secondary progressive disease (SPMS) that is refractory to current therapeutics (Thompson et al. 2022). Thus, understanding how relapses occurs can be used to prevent patients with RRMS to transition to SPMS. Since 1965, several studies had connected infections with the incidence of relapses in these patients. Of interest, around 20-40% of pwMS suffer a relapse after contracting upper respiratory infections such as the one caused by influenza A virus (IAV). Thus, the goal of this dissertation was to understand how the non-neurotrophic influenza A virus (IAV) infection led to increased number of relapses and exacerbation of symptoms in murine models of relapsing-remitting multiple sclerosis. Data collected from four major experiments indicated that IAV caused glia activation, that we can inhibit microglia activation with pharmacological inhibitors, causes neuroinflammmation, increased number of immune cell surveillance into the brain and meninges, and changes T cells encephalitogenecity. Influenza infection is a contagious virus that infect the respiratory tract and affect millions of people every year. Previous studies have identified influenza virus as a potential trigger of multiple sclerosis exacerbation and relapses. To better understand how influenza infection lead to glia activation, single cell RNA-sequencing was performed from IAV infected C57BL/6J mice day 8 p.IAV. We were the first in report that influenza infection causes glia activation at a single cell level. Ontology of differentially expressed genes between global populations analysis indicated that IAV not only affect the glia cells but also other cells from the brain. Finally, we noticed that influenza infection could be modulating glia activation by altering colony stimulating factor receptor (CSFR)1 signal pathway, and confirmed that inhibition of this receptor using GW2580 can mitigate some of these changes in a region specific matter. Microglia activation and proliferation are hallmarks of many neurodegenerative disorders and may contribute to disease pathogenesis. Several studies suggest that this can be modulated by using CSFR1 antagonists. However, it is not known how treatment with non-penetrant CSF1R antagonists, such as GW2580, affect the normal physiology of microglia. To determine how GW2580 affects microglia function, mice were orally gavage, and then body weights, burrowing behavior, circulating leukocyte populations, brain microglia morphology, and the transcriptome of magnetically isolated adult brain microglia were determined. Body weights, burrowing behavior, and circulating leukocytes were not affected by treatment. However microglia morphology was altered without affecting cell viability. Analysis of RNA-sequencing data indicated that genes related to reactive oxygen species (ROS) regulation and survival were suppressed by treatment. In vitro data indicated that microglia viability is affected by treatment when cells are concurrently stimulated with LPS, an inducer of ROS. Pre-treatment with the ROS inhibitor reverted this effects. Together, these data suggest that partial CSF1R antagonism may render microglia more susceptible to reactive oxygen and nitrogen species. Next, we tested the ability of IAV infection to influence disease progression using various murine experimental autoimmune encephalomyelitis (EAE) models of MS. We found that IAV inoculation administered after peak symptoms of EAE exacerbated disease in a mouse strain-independent manner which was associated with increased inflammation occurring within the brain and meninges. Characterization of immune cell infiltrates by flow cytometry revealed virus-inoculated mice had increased numbers of IFN-γ and GM-CSF producing T cells, as well as myeloid cells in the brain and Likewise, peripheral lymphocytes from IAV-inoculated mice produced more GM-CSF and IFN-γ following auto-antigenic stimulation. In agreement with these findings, IAV-pulsed bone marrow derived dendritic cells secreted IL-12p70, IL-1β and IFN-γ in a dose-dependent manner, but did not produce either IL-6 or IL-23. Myelin-specific T cells primed by IAV-pulsed dendritic cells upregulated GM-CSF and were found to be more encephalitogenic upon adoptive transfer into naïve Rag1-/- recipients than those primed by dendritic cells under control conditions. Taken together, these data show that respiratory IAV infection can exacerbate EAE and does so in a manner that is, in part, attributable to actions occurring outside of the brain. Finally, we tested the ability of glycyrrhizin treatment, a triterpenoid compound with anti-HMGB1 properties to influence IAV infection-induced relapses in an EAE model. Treatment with glycyrrhizin could serve as a potential therapy to prevent relapses after infection in patients with RRMS. We found that treatment did not altered disease progression in IAV infected mice, or reduced the number of relapses. Characterization of immune cell infiltrates by flow cytometry in the lung, CNS tissue, spleen and cervical lymph nodes showed that treatment with glycyrrhizin did not altered the number of T cells or myeloid cells in the CNS, but it did in the lung of IAV infected mice. Similarly, peripheral lymphocytes stimulated with autoantigenic myelin peptide from IAV-inoculated mice produced more GM-CSF and IFN-γ and it was ameliorated by treatment. Taken together, these data show that respiratory IAV infection can exacerbate EAE and glycyrrhizin treatment cannot prevent changes in the CNS, even though it does in the peripheral tissues.

Graduation Semester

2022-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Katiria Soto-Diaz

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