fhl2b expression ameliorates muscular dystrophy [5dpf trunk]

In muscle dystrophies, muscle fibers loose integrity and die, leading to significant suffering and a shorter life. Strikingly, the extraocular muscles (EOMs), controlling eye movements, are spared and function well despite the disease progression. Although EOMs have been shown to have important differences compared to body musculature the mechanisms underlying this inherent resistance to muscle dystrophies remain largely unknown. Here, we demonstrate important differences in gene expression as a response to muscle dystrophies between the EOMs and trunk muscle in zebrafish via transcriptomic profiling. We show that the LIM-protein Fhl2 is upregulated in response to knockout of desmin, plectin and obscurin, intermediate filament proteins causing different muscle dystrophies, and contributes to disease protection of the EOMs. Moreover, we show that ectopic expression of fhl2b can partially rescue the muscle phenotype in the zebrafish Duchenne muscular dystrophy model sapje, significantly improving their survival rate. Therefore, fhl2 is a protective agent and a candidate target gene for therapy of muscle dystrophies. Overall design: To examine the effect of fhl2b overexpression in muscle in the background of the dmd/sapje mutant line at 5 dpf