A research team has unlocked a potential alternative approach to manufacturing induced pluripotent stem cells (IPSCs).
Scientists at The Scripps Research Institute (TSRI) found a way to harness antibodies that were able to help “reprogram” ordinary adult cells into this type of stem cell.
The team screened a library of 100 million antibodies and discovered several that could initiate this reprogramming process by eliminating three of the steps typically involved in creating IPSCs.
The standard procedure for IPSC induction involves the insertion into adult cells of genes for four transcription factor proteins: Oct4, Sox2, Klf4 and c-Myc. Activating these genes makes the transcription factor proteins they encode start production and, in turn, change these cells into IPSCs.
However, this approach carries risks, including overproduction of the nuclear reprogramming factors, which could damage cell DNA. IPSCs that are manufactured can have variable properties.
Here’s how the experiment was done.
The scientists started their journey searching for antibodies that could replace both Sox2 and c-Myc. A large population of mouse fibroblast cells was cultivated and scientists inserted the genes for the other two transcription factors, Oct4 and Klf4.
Next, they added the massive library of antibody genes to the cell population so each one contained the genes of one or more of the antibodies.
This move helped the team observe which of the cells started forming stem cell colonies , which led them to identify identify viable antibodies that could duplicate the functions of Sox2 and c-Myc. Performing more tests revealed two additional antibodies that could replace Oct4.
“This result suggests that ultimately we might be able to make IPSCs without putting anything in the cell nucleus, which potentially means that these stem cells will have fewer mutations and overall better properties,” said Kristen Baldwin, senior study author and associate professor in TSRI’s department of neuroscience, in a statement.
Ultimately, these findings indicate a new way to not only pinpoint antibodies that can replace these transcription factors, but also provide a way to study the natural signaling pathways through which these antibodies work.
More tests need to be done in order to find a replacement for Klf4. Baldwin and her colleagues will also launch a larger, more complex antibody-screening process using human cells instead of mouse ones.
The results of this investigation appeared in the journal Nature Biotechnology.