Mapping_of_ENU_mutants_with_defective_resolution_of_neutrophilic_inflammation

Neutrophilic inflammation causes damage to a range of tissues and organs, and is responsible for much suffering and death, particularly in the developed world. There are currently no therapies that lead to “resolution” of inflammation, by targeting the neutrophil for removal. Much is now known about how neutrophils are attracted into sites of inflammation, but much less is known about how they are removed. It is known that neutrophils undergo apoptosis and these apoptotic cells are then cleared by macrophages. However, the molecular controls of this process, and the alternative fates for neutrophils have not been fully characterised. In order to better understand the molecular controls of inflammation resolution, our laboratory has performed the first genetic screen to look at dynamic neutrophil function. In the laboratory of Professor Christiane Nüssein-Volhard, we screened a collection of genetic mutants for persisting neutrophilic inflammation following injury. Tailfin injury at day 3 causes neutrophiic inflammation, which resolves spontaneously by 48 hours. Screening at 48 hours for mutants with persisting inflammation, we identified approx. 50 mutants with defective resolution of inflammation. Each of these, if confirmed, will be mutated in a gene that is non-redundantly required for the resolution of inflammation. Identification of these genes will help elucidate the molecular controls of inflammation resolution and bring us closer to finding a cure for these conditions. Currently, 12 mutant lines are being maintained in Sheffield, and 5 lines are ready for mapping now. Detailed characterisation of one such line has revealed a mutant with increased neutrophil numbers, defects in host defence and a pro-inflammatory phenotype. A mapping panel has been generated, and similar panels are soon to be generated from another 4 lines. We propose to use exome capture and deep sequencing to identify the mutation site in these mutants.