Human Cellular Model of Hypoxic Brain Injury of Prematurity

Extremely premature birth is associated with an increased risk for hypoxic brain injury due to lung immaturity and this results in severe long-term neurodevelopmental impairments. The susceptible cell types in the cerebral cortex at this critical developmental time point and the molecular mechanisms underlying associated gray matter defects in premature infants are not known. Here, we used a human three-dimensional (3D) cellular system to study the effect of changes in oxygen tension on the mid-gestation human cerebral cortex. We identified specific defects in intermediate progenitors, a cortical cell type associated with the expansion of the human cerebral cortex, and show that these are related to the unfolded protein response (UPR) and cell cycle changes. Moreover, we verify these findings in human primary cortical tissue and demonstrate that a modulator of the UPR pathway can prevent the reduction in intermediate progenitors following hypoxia. We anticipate that this human cellular platform will be useful in studying other environmental and genetic factors underlying brain injury in premature infants. We investigated the transcriptional changes associated with exposure to <1% O2 by performing RNA sequencing. Overall design: RNA-seq, 101 bp singlepaired-end reads; minimum of 40 million high quality reads per sample) at 24 and 48 hours (middle and end of <1% O2 for hypoxic condition), as well as after 72 hours of re-oxygenation at 21% O2.