Biology subjects

Mobley, B. C.

Publications and source records attributed to Mobley, B. C..

7 recordsLinked to original sources

bioRxiv2026

Serpin A3 is Increased in Cerebral Amyloid Angiopathy and ARIA

Vascular pathology is an important contributor to dementia, and astrocyte dysfunction is increasingly recognized as a key mediator of cerebrovascular injury. Serpin A3 is a well-known marker of reactive astrocytes, yet its role in vascular degeneration in cerebral amyloid angiopathy and Alzheimers disease remains poorly defined. We combined analyses of single-nucleus transcriptomic datasets with western blotting and quantitative two- and three-dimensional microscopy of human brain tissue to characterize Serpin A3 expression, distribution, cellular sources, and neuropathological correlates in the human brain. Serpin A3 protein abundance was increased in cases with cerebral amyloid angiopathy and Alzheimers disease compared to neurological controls, both by western blot and quantitative microscopy. The tissue distribution of Serpin A3 was heterogeneous and was predominantly within astrocytes associated with degenerating arterioles. Serpin A3 was also detected around parenchymal beta-amyloid plaques. In a postmortem case of active and severe lecanemab-associated amyloid-related imaging abnormalities, light sheet microscopy revealed prominent Serpin A3 immunoreactivity around inflamed, dilated vessels and microhemorrhages, with Serpin A3 levels higher than those found in the Cerebral Amyloid Angiopathy cases. These findings identify Serpin A3 as a marker of cerebrovascular injury and astrocyte-driven inflammatory responses in cerebral amyloid angiopathy.

neuroscience↗

bioRxiv2026

ATF4 Coordinates Transcriptomic and Structural Adaptations in Aging Muscle

Aging is associated with a progressive loss of skeletal muscle function, known as sarcopenia; however, the molecular mechanisms coordinating cellular stress responses and structural adaptations permissive of sarcopenia remain incompletely understood. In our previous studies, we found aging differentially impacted mitochondrial networks by muscle, suggesting unique stress thresholds and response activation. Here, we investigate the role of activating transcription factor 4 (ATF4), a master regulator of the integrated stress response (ISR), in aged quadriceps muscle using complementary patient and aging mouse models. Older adults exhibited a marked decrease in aerobic capacity, muscle strength, and endurance when compared with young participants. These results paralleled findings in aged mice, with significant loss of muscle mass across multiple hindlimb muscles. Ultrastructural analysis revealed substantial age-related changes in mitochondrial morphology, including increased volume, surface area, and branching index, as well as a shift toward larger, more complex mitochondria. Our data indicate that ATF4 binds directly to the promoter region of the gene encoding TFAM, suggesting a transcriptional regulatory relationship to support DNA stability. These structural and transcriptional changes likely impair oxidative capacity and drive a feed-forward cycle of mitochondrial dysfunction and ISR activation. Our findings indicate that ATF4 coordinates transcriptomic and structural adaptations in aging muscle, identifying the ISR pathway as a potential therapeutic target for preserving muscle function in older adults.

cell biology↗

bioRxiv2025

Amyloid-β-regulated gene circuits for programmable Alzheimer's disease therapy

Alzheimer's disease (AD) is a neurodegenerative disease characterized in part by the accumulation of the protein amyloid-{beta} (A{beta}). Monoclonal antibodies (mAbs) that target A{beta} for clearance from the brain have received FDA approval; however, these therapies are accompanied by serious side effects, and their cognitive benefit for patients remains of tremendous debate. Here, we present a potential engineered cell therapy for AD in which we enlist cells of the central nervous system as programmable agents for sculpting the neurodegenerative niche toward one that mitigates glial reactivity and neuronal loss. We constructed a suite of A{beta}-sensitive synthetic Notch (synNotch) receptors from clinically tested anti-A{beta} mAbs and show that cells expressing these receptors can recognize synthetic A{beta}42 and A{beta}40 with differential sensitivity. We express these receptors in astrocytes, cells native to the brain that are known to become dysfunctional in AD. These synNotch astrocytes, which upregulate selected transgenes upon exposure to synthetic and human brain-derived amyloid, were engineered to express potential therapeutic transgenes in response to A{beta}, including brain-derived neurotrophic factor and antagonists of the cytokines tumor necrosis factor and interleukin-1. SynNotch astrocytes that express such antagonists in response to A{beta} partially attenuate a cytokine-induced reactive astrocyte phenotype and promote barrier properties in brain microvascular endothelial cells. Additionally, engineered A{beta}-synNotch cells potently upregulate transgene expression in response to A{beta} deposited in the 5xFAD mouse brain, demonstrating the capacity to recognize A{beta} in situ. Overall, our work supports A{beta}-synNotch receptors as promising tools to generate a cell-based therapy for AD with targeted functionalities to positively influence the AD niche.

bioengineering↗

bioRxiv2024

IL-8 Instructs Macrophage Identity in Lateral Ventricle Contacting Glioblastoma

Adult IDH-wildtype glioblastoma (GBM) is a highly aggressive brain tumor with no established immunotherapy or targeted therapy. Recently, CD32+ HLA-DRhi macrophages were shown to have displaced resident microglia in GBM tumors that contact the lateral ventricle stem cell niche. Since these lateral ventricle contacting GBM tumors have especially poor outcomes, identifying the origin and role of these CD32+ macrophages is likely critical to developing successful GBM immunotherapies. Here, we identify these CD32+ cells as M_IL-8 macrophages and establish that IL-8 is sufficient and necessary for tumor cells to instruct healthy macrophages into CD32+ M_IL-8 M2 macrophages. In ex vivo experiments with conditioned medium from primary human tumor cells, inhibitory antibodies to IL-8 blocked the generation of CD32+ M_IL-8 cells. Finally, using a set of 73 GBM tumors, IL-8 protein is shown to be present in GBM tumor cells in vivo and especially common in tumors contacting the lateral ventricle. These results provide a mechanistic origin for CD32+ macrophages that predominate in the microenvironment of the most aggressive GBM tumors. IL-8 and CD32+ macrophages should now be explored as targets in combination with GBM immunotherapies, especially for patients whose tumors present with radiographic contact with the ventricular-subventricular zone stem cell niche. - IL-8 is expressed by GBM cells and enriched in lateral ventricle-contacting tumors - M_IL-8 macrophages are CD32+ HLA-DR++ CD163+ CD206+ CD86- PD-L1- - M_IL-8 macrophages instructed with IL-8 or GBM conditioned medium match human glioblastoma associated macrophages - IL-8 is necessary for GBM tumor cells to generate M_IL-8 macrophages

cancer biology↗

bioRxiv2024

Multiparameter Quantitative Analyses of Diagnostic Cells in Brain Tissues from Tuberous Sclerosis Complex

The advent of high-dimensional imaging approaches offers innovative opportunities to molecularly characterize diagnostic cells in disorders that have previously relied on histopathological definitions. One example of such disorders is tuberous sclerosis complex (TSC), a developmental disorder characterized by systemic growth of benign tumors. Within resected brain tissues from patients with TSC, detection of abnormally enlarged balloon cells (BCs) is pathognomonic for this disorder. Though BCs can be identified by an expert neuropathologist, little is known about the specificity and broad applicability of protein markers for these cells, complicating classification of proposed BCs identified in experimental models of this disorder. Here, we report the development of a customized machine-learning workflow (Balloon Identifier; BAIDEN) that was trained to prospectively identify BCs in tissue sections using a histological stain compatible with high-dimensional cytometry. This approach was coupled to a custom antibody panel and 36-parameter imaging mass cytometry (IMC) to explore the expression of multiple previously proposed BC markers and develop a descriptor of BC features conserved across multiple tissue samples from patients with TSC. These findings comprise a toolbox and dataset for understanding the abundance, structure, and signaling activity of these histopathologically abnormal cells, and an example case of how such tools can be developed and applied within human tissues.

neuroscience↗

bioRxiv2022

Immune cell regulation in stem cell niche contacting glioblastomas.

Glioblastomas (GBM) are tumors for which immune-targeted therapies have failed to show clinical benefit and for which few biomarkers provide context for meaningful therapeutic stratification. Radiographic contact of GBM tumors with the lateral ventricle stem cell niche correlates with worse patient prognosis; however, the extent to which proximity to the ventricle impacts antitumor immunity remains unknown. We demonstrate that T cell checkpoint receptor expression is elevated in ventricle-contacting GBM as is the abundance of a specific, suppressive CD32+CD44+HLADhigh myeloid population suggesting a distinct immunoregulatory influence on antitumor immunity in proximity to the lateral ventricle. Phospho-specific mass cytometric profiling revealed extensively impaired immune signaling in ventricle-contacting GBM in response to inflammatory cytokine stimulation, further supporting a suppressive milieu influencing immunity at the lateral ventricle. Collectively, we identify a regulatory impact of ventricle contact on antitumor immunity in the brain, and reveal novel clinically targetable mechanisms of immunomodulation in patients with glioblastoma. Significance StatementWe demonstrate that the immune microenvironment of glioblastoma tumors contacting the lateral ventricle differs from non-contacting tumors. This work connects immune-biology to a radiographically detectable feature, the lateral ventricle, and highlights non-invasive imaging as a means to identify targetable immune features in glioblastoma tumors.

immunology↗

bioRxiv2019

High risk glioblastoma cells revealed by machine learning and single cell signaling profiles

Recent developments in machine learning implemented dimensionality reduction and clustering tools to classify the cellular composition of patient-derived tissue in multi-dimensional, single cell studies. Current approaches, however, require prior knowledge of either categorical clinical outcomes or cell type identities. These algorithms are not well suited for application in tumor biology, where clinical outcomes can be continuous and censored and cell identities may be novel and plastic. Risk Assessment Population IDentification (RAPID) is an unsupervised, machine learning algorithm that identifies single cell phenotypes and assesses clinical risk stratification as a continuous variable. Single cell mass cytometry evaluated 34 different phospho-proteins, transcription factors, and cell identity proteins in tumor tissue resected from patients bearing IDH wild-type glioblastomas. RAPID identified and characterized multiple biologically distinct tumor cell subsets that independently and continuously stratified patient outcome. RAPID is broadly applicable for single cell studies where atypical cancer and immune cells may drive disease biology and treatment responses.

cancer biology↗