Cell Service: Gene Therapy Causes β-Cell Growth and Reversal of Type 1 Diabetes in Mice
What to Know
Type 1 diabetes is a disease that causes the body’s immune system to destroy insulin producing β-cells in the pancreas. So far, efforts to cure type 1 diabetes have been limited because there is a need for cells that can be transplanted to replace lost β-cells. Transplanting islets, which are clusters of pancreas cells that contain β-cells, has also run into difficulties. Researchers in this study attempted a different method, in mice.
The researchers transferred two types of genes into mice bred to have diabetes: Ngn3, a gene that helps the body to form islet cells, and Btc, a gene that encourages islet cells to grow. They then monitored the mice for 14 weeks to see whether they made new β-cells and whether those new cells affected their diabetes. The researchers injected some of the mice with another substance called PD-L1, a protein that affects the immune system, to see if it may help the process to succeed.
The gene transfer caused new islets to form in the mice’s livers, not in their pancreases. The immune system quickly destroyed them unless PD-L1 was also transferred. The islets in three-fourths of the PD- L1 treated mice survived for more than 14 weeks and performed just like pancreatic islets. These mice had normal blood glucose levels within 1 to 2 weeks of receiving the genes. This means that their diabetes was reversed. PD-L1 also appeared to suppress the immune system in a targeted way, protecting the new islets without affecting the way the immunes system functions throughout the body.
This study demonstrates that gene therapy may eventually be able to cure type 1 diabetes. However, the research is in very early stages. Also, the method used by the researchers was performed on mice. Whether it will be effective in people remains unknown.
PD-L1–driven tolerance protects neurogenin3-induced islet neogenesis to reverse established type 1 diabetes in NOD mice, by Li and colleagues. Diabetes 2015;64:529–540 https://doi.org/10.2337/db13-1737