AAV8 Ins1-Cre Can Produce Efficient β-Cell Recombination but Requires Consideration of Off-Target Effects
This week we profile a recent publication in Scientific Reports from Adam Ramzy
(pictured below) in the laboratory of Dr. Timothy Kieffer at the UBC Life Sciences Institute.
Can you provide a brief overview of your lab’s current research focus?
Diabetes is a chronic disease that affects over 400 million people worldwide and bears a significant morbidity and mortality cost. Patients with diabetes face an insufficiency of the hormone called insulin that is produced by beta-cells in the pancreas which leads to elevated blood sugar levels. Though replacement of insulin by injections has saved millions of lives, patients still face times of frustrating high blood sugar levels that cause heart disease, kidney disease, and eye disease as well as dangerous low blood sugar levels that can cause coma or death. The work in the Kieffer lab centers around the critical observation that by replacing beta-cells in patients with diabetes using donor cells from extremely limited organ donors, patients become insulin independent and largely avoid the complications of diabetes. The Kieffer lab undertakes a broad field of research aimed at better understanding how beta-cells normally develop and function. Through a better understanding of how beta-cells develop and function, we can better develop and study gene therapies aimed at restoring beta-cell function and cell-therapies aimed at replacing beta-cells using a stem cell source of beta-cells.
What is the significance of the findings in this publication?
By selectively and specifically manipulating genes in beta-cells, researchers can interrogate the role of individual genes in the function and development of beta-cells. In order to delete or activate genes, the most prevalent technology uses a tool borrowed from viruses that is a two-part system – a protein called “cre recombinase” that cuts DNA, and a DNA sequence called a “loxP site” that is the cutting target of cre recombinase. By placing loxP sites at specific places in the genome and expressing Cre in specific cells, Cre expressing cells will cut the genome at target sites to activate or inactivate gene expression. Conventionally, expression of Cre in specific cells has required use of special genetically modified mice that are extremely costly and time consuming to generate. As an alternative, we have designed and developed a novel gene therapy tool that can act as a “trojan horse” to selectively deliver Cre to beta-cells in the pancreas. We demonstrate the utility of the tool by studying the impact of loss of the insulin gene on beta-cell identity.
What are the next steps for this research?
This tool will be broadly useful to researchers in the field of diabetes. We have multiple ongoing projects within the lab that will use this tool and we suggest that other research groups consider it as a new option for the study of the role of genes of interest in beta-cells.
This work was funded by:
1. Canadian Diabetes Association (CDA)
2. Canadian Institutes of Health Research (CIHR)3. Studentship support from the CIHR (Vanier Canada Graduate Scholarship) and Vancouver Coastal Health (CIHR-UBC MD/PhD Studentship)
This work was supported by grants from the Canadian Diabetes Association (CDA) and the Canadian Institutes of Health Research (CIHR). Adam Ramzy gratefully acknowledges studentship support from the CIHR (Vanier Canada Graduate Scholarship) and Vancouver Coastal Health (CIHR-UBC MD/PhD Studentship). Eva Tuduri received a fellowship from the CDA.