IL-17 receptor signaling in megakaryocytes and the implications for oral mucosal immune responses during oropharyngeal candidiasis

The role of megakaryocytes (megs) in oral- and craniofacial-related diseases is almost entirely unknown. Recent studies established that megs have immune functions unrelated to platelet biogenesis. While megs are normally found in the bone marrow, populations have been detected in the lungs and we have now found them in the oral cavity. The goal of this project is to investigate the how megs in the oral mucosa respond to cytokine signals during health and oropharyngeal candidiasis (OPC) caused by Candida albicans. Oral meg populations expand during OPC, and this expansion requires the proinflammatory cytokine interleukin-17 (IL-17), but how the cytokine influences the process of megakaryopoiesis in the oral cavity is unknown. IL-17 is a central immune hub in the oral mucosa and critical for protection during OPC. The long-term goal is to elucidate the role of IL-17 receptor (IL-17R, subunits RA and RC) signaling in megs which would establish a new paradigm form IL-17 signaling in hematopoietic cells in mediating protection against OPC. This is a critical to understand since OPC infections are a major complication for the immunocompromised including cancer and HIV+ patients. The overall objective of is to determine how megs contribute to IL-17R-mediated oral mucosal immune responses. The central hypothesis is that is that IL-17R signaling specifically in megs is immunologically relevant during OPC. This hypothesis is based in part on preliminary data produced in the PI’s laboratory. The rationale that underlies the proposed study is that once it is known how megs participate in oral mucosal immunity, therapeutics involving megs can be developed to effectively treat Candida infections and vascular diseases. This hypothesis will be tested in the following Aims: 1A) To assess the responses of human meg cell line (MEG-01) to IL-17; 1B) To determine the components important in signaling downstream of the IL-17R in MEG-01 cells. RNA-Seq and qPCR analysis will elucidate the genes expressed when cells are stimulated with IL-17 alone or in combination with other agonists. We will assess signaling components downstream of IL-17R through siRNA knockdown. In Aim 2A and B we will define meg-specific IL-17RA signaling during OPC by crossing platelet-factor 4-Cre recombinase mice (PF4-Cre; expressed by megs) with Il17rafl/fl mice. We will expand our studies to also focus on the noncanonical NF-kB transcription factor Ikbz (encoded by Nfkbiz) which is activated by IL-17. To understand the role of IkBz in megs, we will target the Nfkbiz gene selectively in megs using the PF4-Cre mice crossed with the Nfkbizfl/fl mice. We hypothesize that IL-17RA through activation of IkBz contributes to immune responses specifically mediated by megs during OPC, and mice deficient in these signaling components will be susceptible to OPC. Understanding the immune functions of oral megs will have a transforming effect on the field of meg/platelet biology and oral mucosal immunity. This proposal opens the potential for the oral health field to reevaluate the contribution of megs in other oral inflammatory conditions that IL-17R signaling is using the tools we will generate. Project Number: 1R15DE034954-01 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Dental and Craniofacial Research (NIDCR) | Principal Investigator: Heather Conti | Institution: UNIVERSITY OF TOLEDO, TOLEDO, OH | Award Amount: $473,632 | Activity Code: R15 | Study Section: Special Emphasis Panel[ZRG1 MSOS-Q (80)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11123685