Bacterial Induced Calcium Dynamics in Dendritic Cells In Vivo 2225

Abstract Description Dendritic cells (DCs) are sentinels that orchestrate immune responses to infections, cancer, and tissue damage. DCs play a crucial role bridging the innate and adaptive immune systems, eliciting tailored adaptive immune responses. Manipulation of DCs is critical for vaccination, DC-based immunotherapies have been tested in clinical trials as anti-cancer therapeutics and for treatment of infectious diseases. Calcium, a ubiquitous secondary messenger, regulates many critical effector functions of DCs like phagocytosis, maturation, migration, and cytokine production. However, calcium’s dynamics in DCs remains poorly understood. To decipher calcium signals induced by bacterial stimuli in DCs intravitally, we generated CD11c-Salsa6f reporter mice that express the fluorescent protein (FP) construct tdTomato fused to GCaMP6f in CD11c expressing cells. Expression of tdTomato, a red FP, highlights cell shape, and GCaMP6f, which fluoresces green upon calcium binding, visualizes intracellular calcium levels. Using intravital microscopy on mice intravenously injected with bacteria, we discovered oscillatory calcium signaling in splenic that are specific to the type and viability of bacteria. Additionally, the intensity of calcium signal correlated with reactive oxygen species production. This intravital study on splenic DCs underscores the crucial role of calcium homeostasis in response to bacteria, and how it affects downstream pathways crucial for control of bacterial infections. Funding Sources Krieger Klein Alzheimer’s Research Center Pilot Award in collaboration with Dr. Max Tischfield, “Piezo1 restoration of glymphatic waste clearance in aging and Alzheimer’s disease” Topic Categories Antigen and Dendritic Cell Processing, Presentation, and Biology (AGDC)