Friday, May 3, 2024
5/3/2024
PROJECT SUMMARY Alzheimer’s disease (AD) is the leading cause of age-related dementia, in which neuroinflammation is highlighted to play a critical role in driving neurodegeneration. Emerging evidence has demonstrated crucial roles for peripheral immune cells in AD pathology by direct infiltration into brains and regulating brain-resident immune cells, including microglia. However, many critical questions remain unaddressed. Previously, our team developed a three-dimensional (3D) triculture model of AD with human microglia to study the interactions between microglia and AD neural cells. Although our 3D triculture model with microglial cells recapitulates robust neuroinflammation and neurodegeneration, it lacks another critical player in AD pathogenesis, peripheral immune cells. Therefore, we recently developed a unique 3D multicellular human Peripheral immune Chip (PiChip) model to overcome this limitation. This 3D neuroimmune axis model faithfully recapitulates AD pathology with innate and adaptive immune components. Our preliminary data from the PiChip model demonstrated a dramatic increase in the number of human T cells (but not B cells) selectively infiltrating into AD cultures versus control. Infiltration of CD8+ T cells into AD cultures led to microglial activation and it plays a critical role in exacerbating neuroinflammation and neurodegeneration in 3D AD PiChip models. In addition, we discovered key roles for the C-X-C motif chemokine ligand 10 (CXCL10) and its receptor, CXCR3, in regulating T-cell infiltration into AD cultures. Modulating this T cell CXCL10/CXCR3 signaling pathway largely prevented neuronal damage in AD neural-glial cultures. Based on these preliminary results, we proposed a comprehensive study underlying mechanisms of AD-specific T-cell recruitment, CD8+ T-cell mediated neural cell death, and their therapeutic implications, using 3D human cellular models, as well as relevant AD mouse models AD models. The overarching goal of this proposal is to use our unique multicellular PiChip system to gain a greater understanding of the crosstalk between CD8+ T cells and brain resident cells (mainly glial cells) in driving AD pathogenesis. We will achieve this goal by addressing the following aims: Aim 1. to study roles and therapeutic applications for blocking T-cell mediated neuronal deficits in AD; Aim 2. to study how CD8+ T cells trigger neurodegeneration via activating glial cells; Aim 3. to explore the roles of T cell activation and clonal expansion in AD pathogenesis. Successful completion of these aims will provide a better understanding of AD-specific mechanisms underlying the interaction of adaptive immune cells and brain resident cells in driving neurodegeneration, addressing a knowledge gap that promises to yield novel insights into better interventions and biomarkers.
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