Project description:Here we studied cellular level changes of hippocampal cells by unbiased single cell RNA-seq using AD mouse models bearing amyloid pathology (PS2APP), or amyloid and tau combined pathology (TauPS2APP) by single cell RNA-seq. We identified 16 different cell types and further characterized responses of microglia, oligodendrocytes, astrocytes and T cells to amyloidosis only and amyloid plus tau combined pathology. Both mouse models exhibited robust microglial responses. We also found distinct responses of oligodendrocytes to different AD pathologies. We observed increased T cell numbers in both mouse models. Current dataset presents diverse transcriptomic responses to AD pathology and provides resources to study molecular mechanisms underlying disease onset and progression.
Project description:Non-neuronal responses in neurodegenerative disease have received increasing attention as important contributors to disease pathogenesis and progression. Here we utilize single-cell RNA-sequencing to broadly characterize responses of twelve cell types in three different mouse models of Alzheimer’s Disease, capturing the effects of tau-only, amyloid-only, or combined tau- amyloid pathology. We characterize microglia, oligodendrocyte, astrocyte, and T cell responses and compare them across these models. Notably, we identify two distinct transcriptional states for oligodendrocytes induced during disease and determine their spatial distribution. Furthermore, we explore the impact of Trem2 deletion in the context of combined pathology. Trem2 knockout mice exhibit severely blunted microglial responses to combined tau and amyloid pathology, but responses from non-microglial cell types (oligodendrocytes, astrocytes, and T cells) are relatively unchanged. These results delineate core transcriptional states that are accessible in the degenerating brain and how they are influenced by a key Alzheimer’s Disease risk gene, Trem2.
Project description:Loss-of-function mutations in TREM2 (triggering receptor expressed on myeloid cells 2) strongly increase Alzheimer’s disease (AD) risk. Preclinical models using Trem2 deletion or overexpression have revealed a protective Trem2 function related to β-amyloid accumulation, a process that is most prominent during the pre-diagnosis stages of AD. The role of TREM2 in later AD stages characterized by tau-mediated neurodegeneration is less clear. To understand Trem2 function in the context of both β-amyloid and tau pathologies, we examined Trem2-deficient mice expressing mutant tau alone (pR5-183 model) or in the TauPS2APP model, in which β-amyloid pathology exacerbates tau pathology and neurodegeneration. Single-cell RNA-sequencing in these models revealed robust disease-associated microglia (DAM) activation in TauPS2APP mice that was both amyloid-dependent and Trem2-dependent. In the presence of β-amyloid pathology, Trem2 deletion further exacerbated tau accumulation and spreading and promoted brain atrophy. Without β-amyloid pathology, Trem2 deletion did not affect these processes. Therefore, TREM2 may slow AD progression and reduce tau-driven neurodegeneration by restricting the degree to which β-amyloid facilitates the spreading of pathogenic tau
Project description:Comparing Trem2-KO;PS2APP and Trem2-WT;PS2APP CD11b+ cells reveals the role of Trem2 in microglial gene expression in amyloid-laden brains. The "SAMPLE_ID" sample characteristic is a sample identifier internal to Genentech. The ID of this project in Genentech's ExpressionPlot database is PRJ0014430
Project description:RNA was purified from intact cerebrocortical tissue of female PS2APP or non-transgenic mice, perfused at 7 or 13 months of age. The "SAMPLE_ID" sample characteristic is a sample identifier internal to Genentech. The ID of this project in Genentech's ExpressionPlot database is PRJ0007648
Project description:Control mCherry virus (Lv13) and mouse mCherry NGFR virus (Lv16) were injected in the Wild Type mouse brain and at 3 dpi, the hippocampi of the mouse were dissected, dissociated, and mCherry positve cells were sorted by FACS for single-cell sequencing.