National Institute of Mental Health 1F30MH139313-01A1

The Role of Immune Cells within Maternal Immune Activation-Induced Behavioral Deficits

This award supports a three-year mentored research project investigating the role of GR-1+ non-microglial myeloid cells in brain development and behavioral deficits caused by maternal immune activation, with implications for neurodevelopmental disorders such as schizophrenia and autism.

Description

This NIH F30 application describes a three-year plan for mentored research and career development for the PI, Jana Badrani. The scientific premise of this proposal is focused on the role of GR-1+ non-microglial myeloid cells (NMCs) on brain development and adulthood behaviors under normal conditions and following maternal immune activation (MIA). MIA encompasses any pro-inflammatory response within the mother during pregnancy and can be caused by infectious and non-infectious stimuli. MIA is a known risk factor for psychiatric and neurodevelopmental disorders, like schizophrenia and autism, in offspring. MIA is also implicated in hematopoietic changes and disruptions in immune cell development and differentiation. Here, we will elucidate the cellular and molecular mechanisms of meningeal and brain non-microglial immune cell interactions with neurons during normal brain development and following a representative MIA model of maternal systemic challenge with polyI:C (PIC). Our preliminary flow cytometric data identifies a prominent GR-1+ NMC population that increases within the brains of male MIA offspring. scRNA-seq analysis identified GR-1+ neutrophil populations in the brain, with significant gene expression changes in PIC offspring compared to vehicle offspring. Male MIA offspring also demonstrated behavioral deficits in the elevated plus maze (EPM). Systemic depletion of GR-1+ cells improved the EPM behavioral deficits in PIC male offspring. Thus, our central hypothesis is that GR-1+ neutrophils in the brain impair neuronal function and behaviors via MMP in male PIC offspring. We will test this hypothesis through immunohistochemistry, flow cytometry, single-cell transcriptomics, and a variety of in vivo experiments, including the use of anti-GR1 depleting antibodies and MMP inhibitors. Understanding the involvement of GR-1+ non-microglial myeloid cells in brain development and following MIA will have a significant impact on our understanding of immune-brain interactions underlying brain homeostasis.

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