Novel treatment for neuronal reoxygenation injuries

Hypoxic-ischemic encephalopathy (HIE) affects newborns where blood-supply to the brain has been blocked during birth. Similarly, restricted blood flow to parts of the brain is the cause of stroke. In both cases when blood flow is re-established the sudden reoxygenation causes formation of reactive oxygen species (ROS) which oxidize biological macromolecules. The oxidation of cellular components is sensed by cells and required to mount an appropriate cellular response by up- or downregulating genes that governs cellular survival. We are now starting to understand how cells sense oxidative stress and here we propose to develop novel molecular tools to control how genes are regulated in response to reoxygenation. Here, we aim to develop tools to manipulate the activity of the proteins that govern these responses, so that we can control the outcome of reoxygenation-related cellular damage. This will provide new tools to study these processes and could in time also be used as a new therapeutic strategy in stroke and HIE management. We will develop novel assays to measure the activity of these stress-sensing proteins and use them to screen for small-molecule inhibitors. After validation these compounds will then be developed into pharmacologically active tool compounds that can rescue neurons from reoxygenation injuries in e.g. HIE or stroke.

Hypoxic-ischemic encephalopathy (HIE) affects newborns where blood supply to the brain has been blocked during birth. Similarly, restricted blood flow to parts of the brain is the cause of stroke. In both cases when blood flow is re-established the sudden reoxygenation causes formation of reactive oxygen species (ROS) which oxidize bases in DNA and other macromolecules. It is now becoming apparent that cells use oxidized DNA bases as regulatory marks to turn genes on or off, through changes in DNA secondary structure mediated by DNA oxidation, or through blocking access of transcription factors to promoters. In preliminary data we have uncovered that mice knockout for a DNA repair factor that recognize oxidized DNA bases, display cerebral ROS-induced transcriptional changes that in activate pro-survival gene expression and confers cerebral resistance to HIE. Since the knockout mice tolerate HIE, we hypothesize that the corresponding inhibitors may represent a new strategy to treat HIE, by allowing fine-tuning of the cerebral inflammatory response. However, no this enzyme has never before been successfully targeted with small molecules. Thus, the overall project aim is to generate potent and selective inhibitors of the DNA repair factor and use these inhibitors to alleviate damages caused by ROS in HIE. Here we propose to perform a high-throughput screen for inhibitors, perform rigorous in vitro and cellular validation and develop then screening hits into potent, selective, pharmaceutically active inhibitors that can potentially be used to alleviate ROS-mediated brain damage in HIE and stroke. These inhibitors may have a large clinical and scientific impact, as HIE is estimated to be responsible for ~23 % of neonatal mortality, whereas stroke is one of the top three causes of death.