Project Abstracts - OPP

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Abstract

Long-term and functional studies of human islets require the use of immunodeficient mice as the transplant
recipient. The study of human beta-cell replication in the transplant setting requires a hyperglycemic hosts.
A reliable, highly reproducible, and easy to use murine transplant host will benefit many HIRN investigators
and the entire field. Current models are not ideal. Because the availability of human islets for
experimentation is unpredictable, preparing NSG mice with STZ just prior to transplant bears the risk of not
having established stable hyperglycemia. In addition, the glycemia in STZ treated mice is variable, adding a
confounding factor to the study. NSG-Akita mice are difficult to breed, as evidenced by the fact that they
are only rarely available from Jackson Labs. The model to be developed here promises to be robust,
viable, and free of severe diabetic symptoms.

The current models, either STZ treatment or NRG-Akita mice, have limitations with the stability of the
hyperglycemic phenotype and/or morbidity of the mouse strain. We propose to derive a stable, highly
reproducible immunodeficient transplant recipient by CRISPR-Cas9 mediated gene targeting of a wellcharacterized
mutation in the GCK gene, encoding glucokinase, directly in NSG zygotes. The new strain of
mice will have stable hyperglycemia (260mg/dl), and is not expected to develop the severe morbidity seen
in Akita mice. The mutation to be generated is a Arg345->stop variant described by Inoue et al. (2004). By
performing targeted mutagenesis in NSG zygotes, we will save 2 to 3 years of backcrossing.

Opportunity Pool Project Sponsored by CTAR.
Awarded: 2018