Biology subjects

McCrea, L. T.

Publications and source records attributed to McCrea, L. T..

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↗

bioRxiv2020

Umbilical cord blood derived microglia-like cells to model COVID-19 exposure

Microglia, the resident brain immune cells, play a critical role in normal brain development, and are impacted by the intrauterine environment, including maternal immune activation and inflammatory exposures. The COVID-19 pandemic presents a potential developmental immune challenge to the fetal brain, in the setting of maternal SARS-CoV-2 infection with its attendant potential for cytokine production and, in severe cases, cytokine storming. There is currently no biomarker or model for in utero microglial priming and function that might aid in identifying the neonates and children most vulnerable to neurodevelopmental morbidity, as microglia remain inaccessible in fetal life and after birth. This study aimed to generate patient-derived microglial-like cell models unique to each neonate from reprogrammed umbilical cord blood mononuclear cells, adapting and extending a novel methodology previously validated for adult peripheral blood mononuclear cells. We demonstrate that umbilical cord blood mononuclear cells can be used to create microglial-like cell models morphologically and functionally similar to microglia observed in vivo. We illustrate the application of this approach by generating microglia from cells exposed and unexposed to maternal SARS-CoV-2 infection. Our ability to create personalized neonatal models of fetal brain immune programming enables non-invasive insights into fetal brain development and potential childhood neurodevelopmental vulnerabilities for a range of maternal exposures, including COVID-19.

neuroscience↗