The Role of Immune Cells within Maternal Immune Activation-Induced Behavioral Deficits - PROJECT SUMMARY 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. The proposed training plan for the PI is sponsored by Dr. Shin-ichi Kano, MD, PhD, and Dr. Farah Lubin, PhD. Included in the training plan are experiences that will help Jana develop in three major areas: (1) rigorous neuroimmunological research in neuro-immune interactions, which includes developing familiarity with existing literature, critical evaluation of data, and training in responsible conduct of research; (2) rigorous training in advanced bioinformatics, high dimensional data analysis, and scRNA-sequencing analysis; and (3) career and professional development, including grant and manuscript writing, scientific communications, and the translation of research findings to clinical applications. This proposal drives the development of skills required for rigorous scientific research in immunology, neuroscience, and bioinformatics necessary for the PI’s future career as a clinician-scientist focused on neuropsychiatry and immunotherapy.
