An inducible model of chronic hyperglycemia

Transgene driven expression of Escherichia coli nitroreductase (NTR1.0) renders animal cells susceptible to the antibiotic metronidazole (MTZ). Many NTR1.0/MTZ ablation tools have been reported in zebrafish, which have significantly impacted regeneration studies. However, NTR1.0-based tools are not appropriate for modeling chronic cell loss as prolonged application of the required MTZ dose (10 mM) is deleterious to zebrafish health. We established that this dose corresponds to the median lethal dose (LD50) of MTZ in larval and adult zebrafish and that it induced intestinal pathology. NTR2.0 is a more active nitroreductase engineered from Vibrio vulnificus NfsB that requires substantially less MTZ to induce cell ablation. Here, we report on the generation of two new NTR2.0-based zebrafish lines in which acute & beta;-cell ablation can be achieved without MTZ-associated intestinal pathology. For the first time, we were able to sustain & beta;-cell loss and maintain elevated glucose levels (chronic hyperglycemia) in larvae and adults. Adult fish showed significant weight loss, consistent with the induction of a diabetic state, indicating that this paradigm will allow the modeling of diabetes and associated pathologies.

Automated summary

Expression of Escherichia coli nitroreductase (NTR1.0) driven by a transgene makes animal cells susceptible to metronidazole (MTZ). Although NTR1.0/MTZ tools have been used in zebrafish studies, they are not suitable for chronic cell loss modeling due to the harmful effects of prolonged MTZ application. By using a more active nitroreductase (NTR2.0) that requires lower MTZ dose, the researchers established two new zebrafish lines for acute & beta;-cell ablation without MTZ-associated intestinal pathology. This study paves the way for modeling diabetes and related pathologies.