Scientists have just successfully converted connective tissue cells to neuronal cells. By using a modification of an existing technique called CRISPR, researchers were able to induce the cells to change to a new type. The findings are in a paper just published in the journal Cell Stem Cell.
CRISPR is a genetic engineering technique that allows scientists to add or remove genes in a genome. Adult connective tissue cells can be converted to stem cells using CRISPR, for example. These stem cells can then grow into other cell types. Generally, converting a cell into a new type requires overwhelming the cell with extra copies of a gene. Researchers can add multiple copies of a “master” gene that triggers the conversion to a new cell type. The downside to this method is that it requires the generation of many extra gene copies. Also, most cells will revert back to their original forms once they stop getting bombarded by the extra genes.
A team of researchers from Duke University modified the CRISPR technique. Rather than add gene copies, the team was able to simply switch genes “on”. By directly activating important genes, they could induce a cell to change to a new type without having to generate gene copies. The researchers took mouse fibroblasts, a type of cell found in connective tissue, and activated the Brn2, Ascl1, and Myt1l genes. After the genes were activated, the fibroblasts changed into neuronal cells. The new neuronal cells began to conduct electrical signals and were a genetic match to natural mouse brain cells. The change was permanent; the cells never reverted back to their original type. The modified CRISPR technique allows cells to remain in their new form without needing constant outside signals.
Researchers have now improved CRISPR, allowing scientists to permanently convert cells to new types. The technique has a lot of potential for gene therapy, medical research, and personalized medications. The team hopes to improve on their technique and work with human cells in the future.
Joshua B Black et al. Targeted Epigenetic Remodeling of Endogenous Loci by CRISPR/Cas9-Based Transcriptional Activators Directly Converts Fibroblasts to Neuronal Cells. Cell Stem Cell (2016).