Generation of an Alexander disease zebrafish model carrying the R239C mutation: transgenesis to omics analysis and validation using multiple experimental approaches

Alexander disease (AxD) is a rare leukodystrophy caused by heterozygous mutations in the GFAP gene. Various in vitro and in vivo models have been developed so far in an effort to uncover the key mechanisms driving this complex. However, none of these models is suitable for investigating the global dysregulation caused by AxD. To address this shortcoming, I have generated a stable transgenic zebrafish line (zAxD) carrying the human GFAP p.R239C mutation, that is associated with severe phenotypes of AxD type I patients. Then, I performed transcriptomics and proteomics analyses on the whole larvae of our zAxD model, confirming the involvement of several pathways such as the immune system response and inflammation, oxidative stress, extracellular matrix, lipoxidation and lipid metabolism, which have previously emerged in more limited omic studies. Interestingly, new pathways emerged as well, including tyrosine and butanoate metabolic processes, and angiogenesis. Biochemical assays confirmed alterations in cell respiration and lipid metabolism as well as elevated oxidative stress. These findings confirm the reliability of the zAxD model to apply a whole-organism approach not only to investigate the molecular basis of the disease. but also, to search for drugs effective in counteracting the emerging pathogenetic pathways.