Identification of Microglia Stem Cell Markers Through Single-cell RNA Sequencing Analysis in the Postnatal Brain
Parastoo Amlashi¹, Victoria Neckles¹, Dr. David Feliciano¹
¹ Department of Biological Sciences; Clemson University, Clemson SC
Although microglia cells have been characterized for their innate and adaptive functions in brain development and CNS maintenance, little is known about the specific region diversity as the brain ages. Studies on microglia on a single-cell level have been carried out to look at the heterogeneity across different regions of the brain during development. Single-cell RNA sequencing is a useful genomic technique that detects spatiotemporal heterogeneity and assesses gene expression in a sample of cells in tissue. This technique has revealed that microglia have unique transcriptomes in early postnatal timepoints with rising regional heterogeneity and decreasing cellular heterogeneity throughout the lifespan. Understanding microglial heterogeneity through single cell RNA sequencing will give a comprehensive view of microglia and their relationship to other immune cells. By identifying markers that are pertinent for microglia function, we will have more insight on how cell populations iare affected by neurodegenerative diseases. Differential gene expression on the RNA-seq data will allow us to seek a population of markers that can be used for in vivo experiments using a transgenic mouse model. The markers that are currently being used are Iba1 (Aif1) and Cd11b (ITGAM). The IBA1 gene is found within round and stellate microglia that may or may not be immunologically active. Meanwhile, the CD11B marker represents microglia that are immunologically active and are therefore considered a marker for stem cells, which are immature. Cell imaging using fluorescence microscopy demonstrates that microglia cells that are high in CD11B are round cells and stellate cells are rich in IBA1. The aim of this project is to find a subset of microglia markers in early time embryonic development which can be used for further investigation into immune system development in the neonatal brain.