The Transcriptomic Profiles of Microglia from Respiratory Control Centers in Adult Offspring Exposed to Gestational Intermittent Hypoxia Differ by Sex and CNS Region

Abstract

The in utero environment is well‐known to influence CNS development and microglial function, effects that can last into adulthood. However, fetal brain reprogramming has never been evaluated in the context of sleep‐disordered breathing (SDB) during pregnancy, despite its alarming increase in recent years and the detrimental consequences to the newborn. Here, we tested the hypothesis that maternal exposure to intermittent hypoxia during pregnancy would alter the microglial transcriptome of the adult offspring in CNS regions critical for respiratory neural control. To do this, we utilized a rat model of gestational intermittent hypoxia (GIH) in which dams received intermittent hypoxia (2 min alternating 10.5%/21% O2) or normoxia (2 min alternating 21% O2/21% O2; GNX) for 8 hrs/day from gestational days 10–21. Male and female offspring were grown to adulthood (8–12 wks old) and then challenged with vehicle (HBSS) or lipopolysaccharide (LPS; 1mg/kg, 3h) in order to assess transcriptional responses in both basal and inflammatory conditions. Microglia were immunomagnetically isolated from adult brainstem and cervical spinal cord and total RNA harvested. Sequencing libraries were generated using NEBNext Ultra RNA Library Prep Kit and Illumina paired‐end RNA‐sequencing was performed. The reference genome was built using Bowtie and clean reads were aligned to the reference genome using TopHat. FPKM quantification, differential gene expression levels, and gene ontology analyses in brainstem and spinal cord microglia from GNX and GIH male and female offspring were performed using the DESeq or GOSeq R packages, respectively. Preliminary bioinformatics analyses indicate strong differences in the normal transcriptomes of GNX brainstem and cervical spinal cord microglia. Further, we observed significant sex differences both in basal and LPS‐stimulated microglial gene expression in adult GNX microglia from both CNS regions. Interestingly, GIH potently up and down‐regulated more genes in female spinal cord microglia than in male, and effects of GIH were not detected in the brainstem in either sex. Together, these data suggest that the offspring microglial transcriptome can be changed by maternal exposure to intermittent hypoxia and that these effects can persist into adulthood. Given the importance of microglia‐neuron communication in the neural control of breathing, these microglial gene alterations may impact respiratory and brain immune function in the adult offspring.Support or Funding InformationSupported by NS085226, HL105511 and Wisconsin Alumni Research Foundation UW2020 grant.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.