Interrupted reprogramming converts adult cells into high yields of progenitor-like cells

November 30, 2017

A modified version of iPS methodology, called interrupted reprogramming, allows for a highly controlled, potentially safer, and more cost-effective strategy for generating progenitor-like cells from adult cells. As demonstrated November 30 in the journal Stem Cell Reports, researchers in Canada converted adult mouse respiratory tract cells called Club cells into large, pure populations of induced progenitor-like (iPL) cells, which retained a residual memory of their parental cell lineage and therefore specifically generated mature Club cells. Moreover, these cells showed potential as a cell replacement therapy in mice with cystic fibrosis.

"A major block in the critical path of regenerative medicine is the lack of suitable cells to restore function or repair damage," says co-senior author Tom Waddell, a thoracic surgeon at the University of Toronto. "Our approach starts with purifying the cell type we want and then manipulating it to give those cell types characteristics of progenitor cells, which can grow rapidly but produce only a few cell types. As such, it is much more direct, more rapid, and the batches of cells are more purified."

In recent years, induced pluripotent stem (iPS) cells have generated a great deal of interest as a potentially unlimited source of various cell types for transplantation. This method involves genetically reprogramming skin cells taken from adult donors to an embryonic stem-cell-like state, growing these immature cells to large numbers, and then converting them into specialized cell types found in different parts of the body. A major advantage of this approach is the ability to generate patient-specific iPS cells for transplantation, thereby minimizing the risk of harmful immune reactions.

Despite significant progress, these protocols remain limited by low yield and purity of the desired mature cell types, as well as the potential of immature cells to form tumors. Moreover, there is no standardized approach applicable to all cell types, and the development of personalized therapies based on patient-derived pluripotent cells remains very expensive and time consuming. "We have pursued cell therapy for lung diseases for many years," Waddell says. "One key issue is how to get the right type of cells and lots of them. To avoid rejection, we need to use cells from the actual patient."

To address these issues, Waddell and co-senior study author Andras Nagy of Mount Sinai Hospital developed an interrupted reprogramming strategy, which is a modified version of the iPS methodology. The researchers started to genetically reprogram adult Club cells isolated from mice, transiently expressing the four iPS reprogramming factors, but interrupted the process early, prior to reaching the pluripotent state, to generate progenitor-like cells, which are more committed to a specific lineage and show more controlled proliferation than pluripotent cells.

"The reprogramming process had previously been considered as an all-or-none process," Waddell says. "We were surprised to the extent that it can be fine-tuned by the timing and dosing of the drug used to activate the reprogramming factors. That is interesting as it gives lots of opportunities for control, but it does mean we have lots of work to do to get it right."

The researchers showed that the resulting Club-iPL cells could give rise to not only Club cells, but also to other respiratory tract cells such as mucus-secreting goblet cells and ciliated epithelial cells that produce the CFTR protein, which is mutated in patients with cystic fibrosis. When the Club-iPL cells were administered to CFTR-deficient mice, the cells incorporated into tissue lining the respiratory tract and partially restored levels of CFTR in the lungs without inducing tumor formation. This technology can theoretically be applied to almost any cell type that can be isolated and purified, and isolation of highly purified populations of adult cells from most organs is already possible with existing techniques.

"To create specialized cell types for use in cell therapy requires only that we insert the genes (or use non-transgenic approaches) and then test the drug dose and timing required for each cell type and each patient, so it should be relatively scalable at low cost compared to other approaches using each patient's own cells," Waddell says. "It should be very easy for other labs to use a similar approach."

According to the authors, the approach could be used for a variety of regenerative medicine practices, including cell replacement therapy, disease modelling, and drug screening for human diseases. But there is still a long way to go before clinical translation. For their own part, the researchers plan to test this approach with other cell types, including human cells. They will also try to determine if there are safe ways to engraft these cells in human lungs. "The study is a proof of principle, the way this concept may ultimately be used in humans could be different, and it will be many years before this will be attempted in humans," Waddell says.
-end-
This work was funded by an Astellas Clinical/Basic Research grant, the Hospital for Sick Children Transplant and Regenerative Medicine Program, the Canadian Institute of Health Research, an Ontario Research Fund Global Leadership Round in Genomics and Life Sciences grant, and a CIHR Foundation grant.

Stem Cell Reports, Guo et al.: "Generation of Induced Progenitor-like Cells from Mature Epithelial Cells Using Interrupted Reprogramming" http://www.cell.com/stem-cell-reports/fulltext/S2213-6711(17)30477-0

Stem Cell Reports, published by Cell Press for the International Society for Stem Cell Research (@ISSCR), is a monthly open-access forum communicating basic discoveries in stem cell research, in addition to translational and clinical studies. The journal focuses on shorter, single-point manuscripts that report original research with conceptual or practical advances that are of broad interest to stem cell biologists and clinicians. Visit http://www.cell.com/stem-cell-reports. To receive Cell Press media alerts, please contact press@cell.com.

Cell Press

Related Cystic Fibrosis Articles from Brightsurf:

Treating cystic fibrosis with mRNA therapy or CRISPR
The potential for treating cystic fibrosis (CF) using mRNA therapies or CRISPR gene editing is possible regardless of the causative mutation.

Cystic fibrosis: why so many respiratory complications?
Cystic fibrosis, one of the most common genetic diseases in Switzerland, causes severe respiratory and digestive disorders.

A newly discovered disease may lead to better treatment of cystic fibrosis
Cystic fibrosis is the most frequent severe inherited disorder worldwide.

New treatment kills off infection that can be deadly to cystic fibrosis patients
The findings, which are published in the journal Scientific Reports, show that scientists from Aston University, Mycobacterial Research Group, combined doses of three antibiotics -- amoxicillin and imipenem-relebactam and found it was 100% effective in killing off the infection which is usually extremely difficult to treat in patients with cystic fibrosis.

Cystic fibrosis carriers are at increased risk for cystic fibrosis-related conditions
A University of Iowa study challenges the conventional wisdom that having just one mutated copy of the cystic fibrosis (CF) gene has no effects on a person's health.

Rare mutations drive cystic fibrosis in Caribbean
Cystic Fibrosis (CF) in the Caribbean is dominated by unusual gene mutations not often observed in previously studied CF populations, according to comprehensive genome sequencing led by physician-scientists at UC San Francisco and Centro de Neumología Pediátrica in San Juan.

Cystic fibrosis carriers at increased risk of digestive symptoms
Researchers have found that carriers of the most common genetic variant that causes cystic fibrosis experience some symptoms similar to those of people with cystic fibrosis.

In cystic fibrosis, lungs feed deadly bacteria
A steady supply of its favorite food helps a deadly bacterium thrive in the lungs of people with cystic fibrosis, according to a new study by Columbia researchers.

Cibio knocks out cystic fibrosis
The fight against cystic fibrosis continues, targeting in particular some of the mutations that cause it.

Hypertonic saline may help babies with cystic fibrosis breathe better
Babies with cystic fibrosis may breathe better by inhaling hypertonic saline, according to a randomized controlled trial conducted in Germany and published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

Read More: Cystic Fibrosis News and Cystic Fibrosis Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.