Stem Cells Created with Gene Editing

Artist depiction of Cas9 protein editing a gene (Jennifer Doudna, University of California – Berkeley)

19 January 2018. A research lab in San Francisco devised a simpler process for creating stem cells from skin cells in mice with the gene editing technique Crispr. A team from the Gladstone Institute, a medical research center affiliated with University of California in San Francisco, and Stanford University describe the process in yesterday’s issue of the journal Cell Stem Cell (paid subscription required).

Researchers led by Gladstone biochemist Sheng Ding, also a professor of pharmaceutical chemistry at UC San Francisco, are seeking simple and more straightforward methods of generating stem cells for research and regenerative medicine. Producing induced pluripotent stem cells, or iPSCs — also known as adult stem cells since they’re derived from existing tissue — usually requires a collection of transcription factors, proteins that reprogram existing cells into stem cells with many of the same capabilities for regeneration as those from embryos.

Instead of a protein cocktail to generate stem cells, Ding and colleagues use the gene editing technique know as Crispr, clustered regularly interspaced short palindromic repeats. Crispr is based on bacterial defense mechanisms that use RNA to identify and monitor precise locations in DNA. The actual editing of genomes with Crispr employs enzymes that cleave DNA strands at the desired points, with Crispr-associated protein 9, or Cas9, being the enzyme used most often.

In this case, the researchers apply Crispr to remodel the Sox2 and Oct4 genes. Sox2 provides instructions for a protein that regulates binding to other genes during an embryo’s development, much like a transcription factor. Oct4 also produces a protein that plays a role in an embryo’s development, as well as providing instructions for transforming stem cells into mature tissue cells.

The team discovered that Crispr editing of either gene can activate the process for reprogramming into stem cells. Using skin cells from mice, the researchers show edits in only one or two locations in each gene are required to trigger the natural reprogramming process. Tests show the stem cells produced with this method are authentic, functioning similarly to stem cells produced with transcription factors.

Ding believes the Crispr stem-cell technique should help fellow researchers, but can have further medical applications. “Having different options to make iPSCs will be useful when scientists encounter challenges or difficulties with one approach,” says Ding in a Gladstone statement. “Our approach could lead to a simpler method of creating iPSCs or could be used to directly reprogram skin cells into other cell types, such as heart cells or brain cells.”

More from Science & Enterprise:

• Broad Institute in Crispr Licensing Program
• First Agricultural Crispr Products Expected by 2020
• Crispr, Stem Cells Produce Precise Arthritis Therapy
• Crispr-Based Diagnostics System Designed
• Univ. of California to Gain European Crispr-Cas9 Patent

*     *     *