Abstract
Currently no treatments exist for preterm infants with diffuse white matter injury (DWMI) caused by hypoxia. Due to the improved care of preterm neonates and increased recognition by advanced imaging techniques, the prevalence of DWMI is increasing. A better understanding of the pathophysiology of DWMI is therefore of critical importance. The integrated stress response(ISR), a conserved eukaryotic response to myriad stressors including hypoxia, may play a role in hypoxia-induced DWMI and may represent a novel target for much needed therapies. In this study, we use in vitro and in vivo hypoxic models of DWMI to investigate whether the ISR is involved in DWMI. We demonstrate that hypoxia activates the ISR in primary mouse oligodendrocyte precursor cells (OPCs) in vitro and that genetically inhibiting the ISR in differentiating OPCs increases their susceptibility to in vitro hypoxia. We also show that a well established in vivo mild chronic hypoxia (MCH) mouse model and a new severe acute hypoxia (SAH) mouse model of DWMI activates the initial step of the ISR. Nonetheless, genetic inhibition of the ISR has no detectable effect on either MCH- or SAH-induced DWMI. In addition, we demonstrate that genetic enhancement of the ISR does not ameliorate MCH- or SAH-induced DWMI. These studies suggest that, while the ISR protects OPCs from hypoxia in vitro, it does not appear to play a major role in either MCH- or SAH-induced DWMI and is therefore not a likely target for therapies aimed at improving neurological outcome in preterm neonates with hypoxia-induced DWMI.
Original language | English (US) |
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Pages (from-to) | 7465-7480 |
Number of pages | 16 |
Journal | Journal of Neuroscience |
Volume | 37 |
Issue number | 31 |
DOIs | |
State | Published - Aug 2 2017 |
Funding
This work was funded by National Institutes of Health Grant NS-34939 to B.P. We thank Dr. David Gozal for his guidance in setting up and using the hypoxic models, as well as Dr. David Rowitch for providing the Olig2/Cre mice, Dr. Douglas Cavener for providingthe PerkFL/FL mice, andDr. DavidRonfor providingthe GADD34-null mice. We also thank Gloria Wright for her help in preparing the figures.
Keywords
- Diffuse white matter injury
- Hypoxia
- Integrated stress response
- Oligodendrocytes
ASJC Scopus subject areas
- General Neuroscience