Abstract
Major illnesses, including heart attack and sepsis, can cause cognitive impairments, depression, and progressive memory decline that persist long after recovery from the original illness. In rodent models of sepsis or subchronic immune challenge, memory deficits also persist for weeks or months, even in the absence of ongoing neuroimmune activation. This raises the question of what mechanisms in the brain mediate such persistent changes in neural function. Here, we used RNA-sequencing as a large-scale, unbiased approach to identify changes in hippocampal gene expression long after a subchronic immune challenge previously established to cause persistent memory impairments in both males and females. We observed enduring dysregulation of gene expression three months after the end of a subchronic immune challenge, Surprisingly, we also found striking sex differences in both the magnitude of changes and the specific genes and pathways altered, where males showed persistent changes in both immune- and plasticity-related genes three months after immune challenge, whereas females showed few such changes. In contrast, females showed striking differential gene expression in response to a subsequent immune challenge. Thus, immune activation has enduring and sex-specific consequences for hippocampal gene expression and the transcriptional response to subsequent stimuli. Together with findings of long-lasting memory impairments after immune challenge, these data suggest that illnesses can cause enduring vulnerability to, cognitive decline, affective disorders, and memory impairments via dysregulation of transcriptional processes in the brain.
Footnotes
(dtchessa{at}umich.edu)
Funding and Disclosures: NIH/NIMH R00 MH0934509 to NCT. The authors declare no conflicts of interest.
Data availability: This data is also publicly available on the following databases: Gene Expression Omnibus (GEO), with GEO accession number GSE126678, and Sequence Read Archive (SRA), with SRA number SRP186132 and BioProject number PRJNA522922
More information on differentially expressed genes in each condition; Reorganization of the analyses/ manuscript
https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE126678
https://www.ncbi.nlm.nih.gov/Traces/study/?acc=SRP186132&go=go