Biology subjects

Chang, T. S.

Publications and source records attributed to Chang, T. S..

3 recordsLinked to original sources

bioRxiv2021

Tau interactome mapping reveals dynamic processes in synapses and mitochondria associated with neurodegenerative disease

Tau (MAPT) drives neuronal dysfunction in Alzheimers disease (AD) and other tauopathies. To dissect the underlying mechanisms, we combined an engineered ascorbic acid peroxidase (APEX) approach with quantitative affinity purification mass spectrometry (AP-MS) followed by proximity ligation assay (PLA) to characterize Tau interactomes modified by neuronal activity and mutations that cause frontotemporal dementia (FTD) in human induced pluripotent stem cell (iPSC)-derived neurons. We established activity-dependent interactions of Tau with presynaptic vesicle proteins during Tau secretion and mapped the exact APEX-tau-induced biotinylated tyrosines to the cytosolic domains of the interacting vesicular proteins. We showed that FTD mutations impair bioenergetics and markedly diminished Taus interaction with mitochondria proteins, which were downregulated in AD brains of multiple cohorts and correlated with disease severity. These multi-modal and dynamic Tau interactomes with unprecedented spatiotemporal resolution shed novel insights into Taus role in neuronal function and disease-related processes with potential therapeutic targets to block Tau-mediated pathogenesis.

neuroscience↗

bioRxiv2019

Identification of conserved proteomic networks in neurodegenerative dementia

Data-driven analyses of human brain across neurodegenerative diseases possess the potential for identifying disease-specific and shared biological processes. We integrated functional genomics data from postmortem brain, including label-free quantitative proteomics and RNA-seq based transcriptomics in an unprecedented dataset of over 1000 individuals across 5 cohorts representing Alzheimers disease (AD), asymptomatic AD, Progressive Supranuclear Palsy (PSP), and control patients, as a core analysis of the Accelerating Medicines Project - Alzheimers Disease (AMP-AD) consortium. We identified conserved, high confidence proteomic changes during the progression of dementias that were absent in other neurodegenerative disorders. We defined early changes in asymptomatic AD cases that included microglial, astrocyte, and immune response modules and later changes related to synaptic processes and mitochondria, many, but not all of which were conserved at the transcriptomic level. This included a novel module C3, which is enriched in MAPK signaling, and only identified in proteomic networks. To understand the relationship of core molecular processes with causal genetic drivers, we identified glial, immune, and cell-cell interaction processes in modules C8 and C10, which were robustly preserved in multiple independent data sets, up-regulated early in the disease course, and enriched in AD common genetic risk. In contrast to AD, PSP genetic risk was enriched in module C1, which represented synaptic processes, clearly demonstrating that despite shared pathology such as synaptic loss and glial inflammatory changes, AD and PSP have distinct causal drivers. These conserved, high confidence proteomic changes enriched in genetic risk represent new targets for drug discovery.\n\nHighlightsO_LIWe distinguish robust early and late proteomic changes in AD in multiple cohorts.\nC_LIO_LIWe identify changes in dementias that are not preserved in other neurodegenerative diseases.\nC_LIO_LIAD genetic risk is enriched in early up-regulated glial-immune modules and PSP in synaptic modules.\nC_LIO_LIAlmost half of the variance in protein expression reflects gene expression, but an equal fraction is post-transcriptional or -translational.\nC_LI

neuroscience↗

bioRxiv2019

Dementia risk genes engage gene networks poised to tune the immune response towards chronic inflammatory states

An emerging challenge in neurodegenerative dementia is understanding how immune-associated genes and pathways contribute to disease. To achieve a refined view of neuroinflammatory signaling across neurodegeneration, we took an integrative functional genomics approach to consider neurodegeneration from the perspective of microglia and their interactions with other cells. Using large-scale gene expression and perturbation data, regulatory motif analysis, and gene knockout studies, we identify and characterize a microglial-centric network involving distinct gene co-expression modules associated with progressive stages of neurodegeneration. These modules, which are conserved from mouse to human, differentially incorporate specific immune sensors of cellular damage and pathways that are predicted to eventually tune the immune response toward chronic inflammation and immune suppression. Notably, common genetic risk for Alzheimers disease (AD), Frontotemporal dementia (FTD) and Progressive Supranuclear Palsy (PSP) resides in specific modules that distinguish between the disorders, but also show convergence on pathways related to anti-viral defense mechanisms. These results suggest a model wherein combinatorial microglial-immune signaling integrate specific immune activators and disease genes that lead to the establishment of chronic states of simultaneous inflammation and immunosuppression involving type 1 interferon in these dementias.

neuroscience↗