Impact of RGS10 on Microglial Cell Migration and Proliferation

Abstract ID 91855 Poster Board 145 Regulator of G protein signaling 10 protein (RGS10) canonically functions as a GTPase activating protein (GAP) for G αi subunits of heterotrimeric G proteins. In recent years, its non-canonical functions have been explored, particularly as it relates to negative regulation of neuroinflammation originating in microglia. During chronic neuroinflammation, which characterizes aging, Alzheimer's and Parkinson's disease, microglia polarize towards a pro-inflammatory state, leading to a build-up of inflammatory factors and neurodegeneration. RGS10 is silenced during microglial activation, contributing to prolonged inflammation. Reintroduction of RGS10 in RGS10−/− mice reduces expression of pro-inflammatory factors and protects neurons from neurodegeneration. However, the mechanisms by which RGS10 is regulated, its role in neuroinflammation and its non-canonical functions are unknown. To understand the function of RGS10 in resting microglia, we studied the transcriptomic landscape using RNA-Sequencing in the murine microglial cell line (BV-2; WT) and CRISPR generated RGS10 knockout BV-2 cells (RGS10 KO). A total of 5 replicates of each genotype were used. We found 1580 differentially expressed genes, of which 460 genes were upregulated and 1120 genes were downregulated in RGS10 KO cells compared to the BV-2 WT cells. Functional analysis was performed using gene ontology and processes like chemotaxis, migration, synapse organization and proliferation were found to be significantly enriched. KEGG pathway analysis revealed that the differentially expressed genes were enriched in pathways such as cell adhesion, cytokine-cytokine interaction, and Rap1 signaling. Following up on migration and cell adhesion, we found 66 cell migration genes and 31 cell adhesion genes. Genes such as Itgal, itga9, itgb7, pecam1, F11r and Sell were found to be overlapping between the two processes. Gene expression for the above genes was validated using RT-qPCR. RGS10 KO cells displayed enhanced migration at both 24 and 48 hours as compared to BV-2 WT cells. RGS10 KO cells also displayed enhanced cell proliferation, another enriched process identified by the RNA-Seq data. Thus, our data shows that apart from its canonical role as a GAP for G αi, RGS10 is also implicated in cell migration and cell proliferation. Further studies to understand the mechanism by which RGS10 modulates migration and cell proliferation are underway, including how the role of RGS10 impacts migration and cell proliferation under an inflammatory stimulus.