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Access Type
WSU Access
Date of Award
January 2024
Degree Type
Dissertation
Degree Name
Ph.D.
Department
Anatomy and Cell Biology
First Advisor
Susmit D. Suvas
Abstract
Herpes Stromal Keratitis is chronic immunoinflammatory condition caused by recurrent HSV-1 infection. This condition, characterized by severe ocular inflammation and tissue damage, poses substantial clinical burdens, necessitating a deeper understanding of its underlying immunopathology for effective therapeutic interventions. Despite significant advancements in elucidating the pathogenesis of HSK, several critical gaps persist in our understanding of the complex immune mechanisms driving disease progression.We standardized an approach to study the differential immune cell infiltration in HSV-1 infected corneal epithelium and stroma using flow cytometry. This technique enabled us to study localization of both innate and adaptive cells during lytic as well as clinical phase of disease. Our analysis of leukocyte dynamics in HSV-1-infected corneas reveals a biphasic influx of immune cells, particularly in the corneal epithelium, underscoring the tissue-specific immune responses underlying HSK. Furthermore, our study investigates the functional significance of innate immune cell infiltration, highlighting involvement of monocytes in preventing viral dissemination to leukocytes during lytic phase and heterogeneity in role of epithelial and stromal neutrophils in wound healing during clinical phase of HSK. Additionally, our study explores the localization and abundance of tissue resident memory T cells (TRMs) within the HSV-1 infected cornea, comparing their presence in the epithelium versus the stroma and between non-HSK and HSK corneas. While the corneal epithelium serves as a primary site for TRM localization, corneas developing HSK exhibit diminished TRM pools, potentially due to functional exhaustion mediated by persistent antigenic stimulation. These findings hold great clinical significance as it might explain as to why patients with history of stromal keratitis are at higher risk of recurrent stromal keratitis. Moreover, the indiscriminate use of topical corticosteroids may compromise HSV-1-induced TRM function, exacerbating viral reactivation and disease recurrence. Our research also examines the prevalence of senescent cells in the corneal epithelium and stroma following HSV-1 infection. It explores the possibility of a two-step senescence pattern within the epithelium and investigates the potential of senescence as an antiviral defense mechanism that limits viral replication by restricting the ability of corneal epithelial cells to proliferate. Furthermore, the presence of senescent monocytes in the corneal stroma might possibly be involved in secretion of pro inflammatory cytokines linking these monocytes with inflamm-aging. Moreover, these monocytes can affect the effectiveness of adaptive immune response by altering the dendritic cells’ antigen presentation capacity.
Next, our study reveals a significant upregulation of F10, the gene encoding Factor X, at both the gene and protein level. The research delves into the potential role of FX in driving the inflammatory response associated with HSK, considering its known link between blood coagulation and inflammatory pathways. Furthermore, the investigation suggests a systemic impact of HSV-1 infection by observing elevated levels of activated Factor Xa in the corneas and plasma samples of infected mice. Finally, the study examines the role of FXa, the activated form of Factor X, as a critical mediator of the inflammatory response, potentially triggering cellular responses through the activation of protease-activated receptors (PARs) and inducing the production of pro-inflammatory cytokines. Immunohistochemistry findings revealed increased localization of F10 and receptor PAR-2 in the anterior stroma in HSK corneas, highlighting its potential role in the disease process. Future investigation is warranted to comment on the pathogenic or beneficial role of F10 in HSK.
Recommended Citation
Setia, Mizumi, "Impact Of Differential Localization Of Immune Cell Subsets In Two Prominent Layers Of Hsv-1 Infected Cornea On The Development Of Herpes Stromal Keratitis" (2024). Wayne State University Dissertations. 4085.
https://digitalcommons.wayne.edu/oa_dissertations/4085