In vivo regulation of neutrophil function by hypoxic signalling. (360G-Wellcome-082909_Z_07_Z)

The unique combination of optical transparency and genetic manipulability make Zebrafish larvae an ideal model for the in vivo study of neutrophil behaviour. Hypoxic signalling is important in determining the outcome of neutrophilic inflammation, but much is unknown about how hypoxic signalling influences inflammation at a molecular level. Using well established transgenic Zebrafish models of inflammation, we will study multiple aspects of neutrophil behaviour during experimentally-induced infla mmation in vivo, and observe the effects of physical, pharmacological and genetic activators of the hypoxic signalling pathway on neutrophil behaviour. Having validated the system for the study of hypoxic signalling, we will study the effect of various gene manipulations on neutrophil behaviour in vivo, and on gene expression profiles. Firstly, we will use mutants in vhl1, the Zebrafish homologue of human vhl, and study in vivo inflammation in heterozygotes and homozygotes. We will compare these mutants to FIH mutants, and to combination mutant/morphants to determine key control points. Finally, we will address the question of the degree of HIF dependence of different neutrophil responses to hypoxic signalling, by using a myeloid specific DN-expressing transgenic line to block the HIF component of hypoxic signalling in the various models described above.