Defining mechanisms that regulate plasma membrane rupture

About This Grant

PROJECT SUMMARY/ABSTRACT Plasma membrane rupture (PMR) is the terminal step of pyroptosis, a form of programmed cell death that plays a critical role in host defense and inflammation. Pyroptotic cell death is especially important in macrophages, where PMR facilitates the release of pro-inflammatory cytokines and danger-associated molecular patterns (DAMPs) that initiate and propagate immune responses. However, dysregulated PMR contributes to the pathology of numerous chronic inflammatory diseases, including Crohn’s disease, systemic lupus erythematosus, and rheumatoid arthritis. Although gasdermin D (GSDMD) pores initiate membrane permeabilization, recent studies have identified ninjurin1 (NINJ1) as a key executor of PMR by oligomerizing into discs and cutting out sections of the cell membrane. Despite this discovery, the molecular mechanisms that regulate NINJ1 activity remain poorly understood. NINJ1 is subjected to glycosylation on asparagine 60 (N60) and can also be cleaved by matrix metalloproteinase 9 (MMP9). However, the functional outcomes of these modifications concerning PMR are unknown. This proposal aims to define how post-translational modifications regulate NINJ1-mediated PMR. I hypothesize that NINJ1 glycosylation and MMP9-mediated cleavage of NINJ1 regulate PMR. In Aim 1, I will investigate how interferon (IFN)-driven glycosylation of NINJ1 promotes its oligomerization. In Aim 2, I will determine how IFN signaling restricts MMP9- mediated NINJ1 cleavage to sustain PMR. These studies will employ a combination of biochemistry, mass spectrometry, microscopy, and genetic models to dissect NINJ1 regulation at a molecular level. This research will provide novel insights into the control of inflammatory cell death and may identify new targets for therapeutic intervention in inflammatory diseases. This proposed training will equip me with expertise in innate immunology, membrane biology, and translational inflammation research, supporting my long-term goal of being an independent investigator in immunology. In addition to the scientific advances made in this project, I will expand my technical skill set and scientific knowledge in the cell death and immunology fields, refine my career development plan and build my resume, and develop my translation research abilities. Together, the work I conduct during this fellowship will support my development to pursue a research career.