Single-cell RNA analysis reveals cell-specific increases in SUR1-related pathway activity with age in murine brain.
Zujian Xiong1, Chaim Sneiderman1, Dhivyaa Rajasundaram1, Dennis Simon1, Joshua Catapano2, Jarrod Rulney2, Sudhanshua Raikwar2, Anupama Rani2, Shima Shahjouei2, Sandra Mihaljevic2, Ethan Winkler2, Keri Janesko-Feldman1, Ria Trivedi1, Vincent Vagni1, Patrick Kochanek1, Ruchira Jha2, Gary Kohanbash1
1University of Pittsburgh, 2Barrow Neurological Institute
Objective:
To explore how age influences sulfonylurea-receptor-1 (SUR1)-related genes and biological processes across cell subtypes of the murine brain by using single cell RNA sequencing (scRNA-Seq).
Background:
SUR1-inhibition therapy is a promising therapeutic strategy being evaluated in a phase-II trial to improve the secondary injuries after traumatic brain injury (TBI). The impact of this therapy may vary with age depending on related differences in gene expression/biological processes.
Design/Methods:
scRNA-Seq was performed on naïve murine brain at two adult ages (12wk=younger, 9mo=older). Individual cell types were annotated and SUR1-related differentially expressed genes (DEGs) were identified (MAST) and pathway activity was predicted (AUCell) based on 202 genes related to SUR1 identified a priori. Biological processes (gene-ontology, GOBP), lineage differentiation/pseudotime (Monocle2), and cell-communication (CellChat) were determined for the SUR1-related pathway.
Results:
55,211 cells were sequenced (25,728=younger, 29,483=older), including 10 cell types and multiple subtypes. Cell subtype distribution varied with age including different subpopulations of microglia, astrocytes, ependymal, endothelial, and mural cells. Neuronal subtypes were similar between ages. Overall, SUR1-pathway activity was higher in older vs. younger mice (all celltypes). A high proportion of astrocytes and endothelial cells had increased SUR1-pathway activity in older mice. Variability in SUR1-pathway activity was seen across cell subtypes. Increased SUR1-pathway activity in microglia and endothelial cells of older mice was associated with alterations in neuronal synaptic plasticity and regulation of neurogenesis contrasting predominantly inflammatory responses in younger mice. Higher SUR1-pathway activity in neurons of older mice was associated with cell death pathways. The number, strength and diversity of cell-communication interactions was greater in younger vs older mice, particularly robust in cells with high levels of SUR1-pathway activity
Conclusions:
There are robust cell-specific age-based biological differences in SUR1-related pathway activity in murine brain. This may facilitate understanding of how this pathway relates to aging, as well as developing age-based therapeutic targets.