Insulin injections can control diabetes, but patients still experience serious complications such as kidney disease and skin infections. Transplanting pancreatic tissues containing functional insulin-producing beta cells is of limited use, because donors are scarce and patients must take immunosuppressant drugs afterward.
Now, scientists at Washington University in St. Louis have developed a way to use gene editing system CRISPR-Cas9 to edit a mutation in human-induced pluripotent stem cells (iPSCs) and then turn them into beta cells. When transplanted into mice, the cells reversed preexisting diabetes in a lasting way, according to results published in the journal Science Translational Medicine.
While the researchers used cells from patients with Wolfram syndrome—a rare childhood diabetes caused by mutations in the WFS1 gene—they argue that the combination of a gene therapy with stem cells could potentially treat other forms of diabetes as well.
“One of the biggest challenges we faced was differentiating our patient cells into beta cells. Previous approaches do not allow for this robust differentiation. We use our new differentiation protocol targeting different development and signaling pathways to generate our cells,” the study’s lead author, Kristina Maxwell, explained in a video statement.
Making pancreatic beta cells from patient-derived stem cells requires precise activation and repression of specific pathways, and at the right times, to guide the development process. In a recent Nature Biotechnology study, the team described a successful method that leverages the link between a complex known as actin cytoskeleton and the expression of transcription factors that drive pancreatic cell differentiation.
This time, the researchers applied the technology to iPSCs from two patients with Wolfram syndrome. They used CRISPR to correct the mutated WFS1 gene in the cells and differentiated the edited iPSCs into fully functional beta cells.
After transplanting the corrected beta cells into diabetic mice, the animals saw their blood glucose drop quickly, suggesting the disease had been reversed. The effect lasted for the entire six-month observation period, the scientists reported. By comparison, those receiving unedited cells from patients were unable to achieve glycemic control.
The idea of editing stem cells with CRISPR has already attracted interest in the biopharma industry. Back in 2018, CRISPR Therapeutics penned a deal with ViaCyte to develop off-the-shelf, gene-editing stem cell therapies for diabetes. Rather than editing iPSCs from particular patients themselves to correct a faulty gene, the pair’s lead project used CRISPR to edit healthy cells so that they lacked the B2M gene and expressed PD-L1 to protect against immune attack. The two companies unveiled positive preclinical data in September.
Other research groups working on gene therapy or stem cells for diabetes include a Harvard University scientist and his startup Semma Therapeutics, which developed a method for selecting beta cells out of a mixture of cells developed from PSCs. Scientists at the University of Wisconsin-Madison recently proposed that removing the IRE1-alpha gene in beta cells could prevent immune T cells from attacking them in mice with Type 1 diabetes.
The Washington University team hopes its technology may help Type 1 diabetes patients whose disease is caused by multiple genetic and environmental factors as well as the Type 2 form linked to obesity and insulin resistance.
“We can generate a virtually unlimited number of beta cells from patients with diabetes to test and discover new drugs to hopefully stop or even reverse this disease,” Jeffrey Millman, the study’s co-senior author, said in the video statement. “Perhaps most importantly, this technology now allows for the potential use of gene therapy in combination with the patient’s own cells to treat their own diabetes by transplantation of lab-grown beta cells.”