Project description:Osteoarthritis (OA) treatment is limited by the lack of effective non-surgical interventions to slow disease progression. Here, we examined the contributions of the subchondral bone properties to OA development. We used parathyroid hormone (PTH) to modulate bone mass prior to OA initiation and alendronate (ALN) to inhibit bone remodeling during OA progression. We examined the spatiotemporal progression of joint damage by combining histopathological and transcriptomic analyses across joint tissues. The additive effect of PTH pretreatment prior to OA initiation and ALN treatment during OA progression most effectively attenuated load-induced OA pathology. Individually, PTH directly improved cartilage health and slowed the development of cartilage damage, whereas ALN primarily attenuated subchondral bone changes associated with OA progression. Joint damage reflected early transcriptomic changes. With both treatments the structural changes were associated with early modulation of immunoregulation and -response pathways that may contribute to disease mechanisms. Overall, our results demonstrate the potential of subchondral bone-modifying therapies to slow the progression of OA.
Project description:Astrocytes are crucial to brain homeostasis, yet their changes along the spatiotemporal progression of Alzheimer’s disease (AD) neuropathology remain largely unexplored. Here, we performed single- nucleus RNA-sequencing of 628,943 astrocytes from five brain regions representing the stereotypical progression of AD pathology, across 32 donors spanning the entire normal aging-to-severe AD continuum. We discovered astrocyte gene expression trajectories that are differentially activated or suppressed at various regions and disease stages. We mapped out several unique astrocyte subclusters that exhibited varying responses to neuropathology across the AD-vulnerable neural network (spatial axis) or AD pathology stage (temporal axis). The proportion of homeostatic, intermediate, and reactive astrocytes changed solely along the spatial axis, whereas two other unique subclusters changed along the temporal axis. One of these, a trophic factor-rich subcluster, declined along pathology stage, whereas the other, defined by proteostasis and metabolic genes, increased in late-stage but unexpectedly returned to baseline levels in end-stage, suggesting exhaustion of response with chronic exposure to neuropathology. Our study underscores the complex and dynamic nature of astrocytic responses in AD and our findings are available at https://ad-progression-atlas.partners.org
Project description:Proliferation of microglia represents a physiologically process which is accelerated in several neurodegenerative disorders including Alzheimer disease. The effect of such neurodegeneration-associated microglial proliferation on function and disease progression remains unclear. We hypothesized that microglial proliferation into a neurodegenerative environment generates subpopulations displaying transcriptional and functional changes that may contribute to the transition from acute to chronic neuroinflammation. Here, we show that proliferation results in profound alterations of cellular function by providing evidence that newly proliferated microglia show impaired beta-amyloid clearance in vivo. Through sorting of proliferating microglia of APP/PS1 mice and subsequent transcriptome analysis, we define unique proliferation-associated transcriptomic signatures that change with age and beta-amyloid accumulation and are characterized by an enrichment of immune system-related pathways.
Project description:Cancer forms a local tumor that subsequently metastasizes to distant organs. In prostate cancer, the latter part of the trajectory is influenced by the inhibition of the androgen receptor (AR). The study of proteomic changes along disease progression may reveal insights into how prostate cancer evolves and open new therapeutic avenues. Here, we profile changes in protein abundance and post-translational modifications (PTMs) along the disease trajectory in patient-derived xenograft models. Our results suggest a key involvement of the RTK-RAS-MAPK pathway during disease progression. We highlight multiple alterations within this pathway including the tumor suppressors NF1 and ERF. Enhanced activity of cyclin-dependent kinases results in the engagement of various DNA repair pathways. Specific PTMs suggest changes in mitochondrial ATP synthesis, proteasomal activity, gene splicing, and TGF beta signaling. Finally, we show how different transcription factors engage with disease progression. A web resource is provided enabling the investigation of dynamic proteomic perturbations.
Project description:Late-onset Alzheimer disease (LOAD) is the most common neurodegenerative disorder worldwide. Recent studies have shown that differential expression in genes (DEG) related to inflammatory response may result associated with disease onset and progression. This study aimed to explore the molecular pathogenesis of LOAD-related inflammation through next-generation sequencing, to assess RNA expression profiles in Alzheimer's disease patients and healthy controls.
Project description:We performed next-generation RNA sequencing (RNA-seq) using brain tissue from 23 months old non-transgenic (NTG), non-treated and CP2 (mitochondrial complex I inhibitor)-treated APP/PS1 (mouse model of Alzheimer`s disease). By comparing transcriptomic data of NTG and vehicle-treated APP/PS1 mice, we found processes affected by the disease in APP/PS1 such as impaired ATP metabolism, ion transport, nervous system development, synaptic transmission, and inflammation. CP2-treatment in APP/PS1 positively affected genes related to immune system, axonogenesis, dendritic spine morphology, synaptic function, among the others. These data demonstrate that pathways improved by CP2 treatment in APP/PS1 mice comprise major pathways essential for therapeutic efficacy in Alzheimer`s disease.
Project description:Microglia activation is a hallmark in Alzheimer Disease. Non-active and Active microglia were isolated from young and aged WT mice and before- and after- pathology mouse models of Alzheimer Disease. Microarray analysis was used to determine the global gene expression programe in microglia during pathological (Abeta or TAU pathology) versus control state.
Project description:RNA samples from the cerebral cortex of APP/PS1 and WT mouse littermates aged 3, 6 and 12 months were analyzed using the Affymetrix Genechip Mouse Gene 1.1 ST Array. The APP-PS1 transgenic mouse express the human mutated forms APPswe and PS1dE9. This is a good model of familial Alzheimer Disease because it reproduces several features of the disease as β-amyloid deposits throughout the brain and exhibit memory impairment by the end of the sixth month and is a simple model to study the molecular pathways. The aim of this study is to identify dysregulation of inflammation pathways in order to understand shifts of inflammation responses with disease progression.