Biology subjects

Bowen, J. J.

Publications and source records attributed to Bowen, J. J..

3 recordsLinked to original sources

bioRxiv2025

Functional Genomic Profiling of Schizophrenia-Associated Genes Reveals Key Microglial Regulators

Microglia are increasingly recognized as key regulators of neural circuit development and putative contributors to the pathophysiology of neuropsychiatric disorders such as schizophrenia (SCZ). However, the functional impact of SCZ-associated genes in microglia remains largely unexplored. Here, we performed an arrayed CRISPR targeting screen of 30 schizophrenia-associated genes predicted to be differentially expressed in human microglia-like cells. Target genes were prioritized based on post-mortem transcriptomic relevance and predicted ontology-based roles in phagocytosis pathways. We quantified phagocytic activity and morphological changes following gene targeting using high-content confocal imaging. Key targets, including CYFIP1, MSR1, TREM2, SYK, ITGB2, ITGAM and IRF8, modulated phagocytosis and altered morphological properties consistent with activation states, validating their functional roles in microglia. To elucidate transcriptional impact, we further applied a multiplexed RNA sequencing platform across gene targets. These analyses revealed gene-specific transcriptional signatures, implicating divergent pathways related to phagocytic, activation, cytoskeletal, and lysosomal function. Together, these findings demonstrate the utility of CRISPR-based functional genomics in characterizing microglia function and identifying new target genes and mechanisms that may underlie their contributions to schizophrenia pathophysiology.

neuroscience↗

bioRxiv2025

Atypical antipsychotics alter microglial functions via astrocyte-derived extracellular vesicles

A limited understanding of the underlying molecular mechanisms of atypical antipsychotics has hindered efforts to develop the next generation of treatments for schizophrenia. In particular, there has been little investigation of how medications like clozapine and olanzapine modulate human non-neuronal cells, including astrocytes and microglia. Recent postmortem and serum-based studies suggest that schizophrenia etiology involves dysregulated cellular communication through extracellular vesicles (EVs). Astrocytes are a major source of these EVs and are strongly implicated in the etiology of schizophrenia by convergent data from human postmortem, brain imaging, RNA-sequencing, and genome-wide association studies. We hypothesized that clozapine and olanzapine can affect microglia biology indirectly via astrocytic secretion of EVs. We used in vitro cellular models with primary human astrocytes and PBMC-derived microglial-like cells to investigate the downstream impact of isolated astrocyte-derived EVs (ADEVs) on microglial phenotypes relevant to schizophrenia, including microglial phagocytosis, motility, and morphology. To model microglia-mediated synaptic pruning in vitro, we utilized image-based quantification of microglia engulfment of isolated human synaptosomes. We found that treatment with ADEVs reduced microglial synaptosome phagocytosis in a dose-dependent manner. This reduction was reversed upon addition of ADEVs isolated from astrocytes treated with norclozapine or olanzapine. ADEVs isolated from clozapine-treated astrocytes increased microglial motility, indicating that clozapine alters microglial surveillance activity without affecting phagocytosis through these ADEVs. Together, these results suggest that atypical antipsychotics have distinct and indirect impact on microglia biology mediated by ADEVs. These results highlight a potentially critical role for ADEVs in regulating glial cell communication and suggest they may be promising therapeutic targets for next-generation antipsychotic development.

neuroscience↗

bioRxiv2024

Identifying brain-penetrant small molecule modulators of human microglia using a cellular model of synaptic pruning

Microglia dysregulation is implicated across a range of neurodevelopmental and neurodegenerative disorders, making their modulation a promising therapeutic target. Using PBMC-derived induced microglia-like cells (piMGLCs) in a scalable assay, we screened 489 CNS-penetrant compounds for modulation of microglial phagocytosis of human synaptosomes in a validated assay for microglia-mediated synaptic pruning. Compounds from the library that reduced phagocytosis by [≥]2 standard deviations across the library without cytotoxicity were validated in secondary screens, with 28 of them further confirmed to reduce phagocytosis by 50% or more. Image-based morphological measurements were calculated to measure the degree of ramified vs. amoeboid morphotype as an indicator of activation state. Additionally, transcriptomic profiling indicated divergent effects on cell signaling, metabolism, activation, and actin dynamics across confirmed compounds. In particular, multiple CNS-penetrant small molecules with prior FDA approval or demonstration of safety in vivo demonstrated modulatory effects on microglia. These potential disease-modifying agents represent high-priority candidates for repositioning studies in neurodevelopmental, neuroinflammatory, or neurodegenerative disorders.

neuroscience↗