AQP4 water channels have been shown to play an important role in development of brain edema following stroke, hyponatremia. However the physiological role of this protein is still controversial.We have evidence showing that AQP4 may be involved in the pathophysiology of several neurodegenerative disorders. Based on a newly described human mutation in the AQP4 gene, we have generated a mouse model with the same single mutation in AQP4 gene (generated by Transgensenteret, IMB) using CRISPR CAS9 technology. This animal model is the first model of a human disease causing mutation in the Aqp4 gene, where the one known patient internationally exhibits intellectual disability, ataxia and progressive motor loss. The gene affected encodes a water channel highly expressed in brain and is of relevance to a number of neurological conditions. Interestingly, it has been shown that the mutation does not affect the water permeability of AQP4, and thus modeling this mutation enables us to study the potential non-channel functions of AQP4, which are involved in neuroinflammation, possibly through an interaction with other brain cell types such as microglia. We are currently performing transcript and protein analysis. The preliminary results show that the mutation affects the protein expression level of AQP4, and also affects the expression of other proteins. We plan to analyze data from both young and aged animals, as the patient has a progressive clinical course. We want to continue heterozygous breeding and investigating this model the following years. We will use organs from the animals ex-vivo, either post perfusion fixation or post decapitation for protein and mRNA expression studies. The main aim of this project is: animal breeding and study on brain and other organs ex-vivo (immunohistochemistry, Western blotting and qPCR).

Either deep anesthesia through i.p. injection of ZRF-cocktail prior to transcardial perfusion fixation, or cervical dislocation and decapitation. We will send additional information or separate applications when in vivo experiments (where surgery or other experiments on live animals is needed)

In order to study the effect of the mutation on the mammalian nervous system, the use of experimental animals cannot currently be replaced. We have considered other model organisms, however in order to study the mutation on a evolutionary level relevant to humans, a mammalian model is necessary. Mice are the most suitable alternative.