Nav: Home

NUS researchers confine mature cells to turn them into stem cells

July 09, 2018

Stem cells are the blank slate on which all specialised cells in our bodies are built and they are the foundation for every organ and tissue in the body.

Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute (MBI) at the National University of Singapore (NUS) and the FIRC Institute of Molecular Oncology (IFOM) in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification - by confining them to a defined geometric space for an extended period of time.

"Our breakthrough findings will usher in a new generation of stem cell technologies for tissue engineering and regenerative medicine that may overcome the negative effects of geonomic manipulation," said Prof Shivashankar.

Turning back the cellular clock

It has been over a decade since scientists first showed that mature cells can be reprogrammed in the lab to become pluripotent stem cells that are capable of being developed into any cell type in the body. In those early studies, researchers genetically modified mature cells by introducing external factors that reset the genomic programmes of the cells, essentially turning back the clock and returning them to an undifferentiated or unspecialised state. The resultant lab-made cells, known as induced pluripotent stem cells (iPSCs) can then be programmed into different cell types for use in tissue repair, drug discovery and even to grow new organs for transplant. Importantly, these cells did not need to be harvested from embryos.

However, a major obstacle is the tendency for any specialised cell that is developed from iPSCs, to form tumours after being introduced into the body. To understand why this occurred, researchers turned their focus to understanding how stem cell differentiation and growth is regulated in the body, and in particular, how cells naturally revert to an immature stem cell-like state, or convert to another cell type, during development, or in tissue maintenance.

Prof Shivashankar's team of researchers has shown that mature cells can be reprogrammed, in vitro, into pluripotent stem cells without genetically modifying the mature cells, simply by confining the cells to a defined area for growth.

Resetting mature cells

When fibroblast cells (a type of mature cell found in connective tissue such as tendons and ligaments) were confined to rectangular areas, they quickly assumed the shape of the substrate (the surface or medium that the cells are attached to). Based on previous work from the Shivashankar lab, this indicated that the cells were measuring and responding to the physical properties of their environment, and conveying this information to the nucleus where DNA packaging and genome programmes would adapt accordingly.

The team grew the cells over 10 days until they formed spherical clusters of cells. Genetic analysis of the cells within these clusters revealed that specific characteristics of chromatin (the condensed form of packaged DNA) normally associated with mature fibroblasts were lost by the sixth day. By the 10th day, the cells expressed genes normally associated with embryonic stem cells and iPSCs. The researchers have now learnt that by confining the mature cells for an extended period of time, mature fibroblasts can be turned into pluripotent stem cells.

To confirm that the fibroblasts had indeed been reprogrammed into stem cells, the researchers then directed their growth, with high efficiency, into two different specialised cell types. Some cells were also directed back into fibroblasts.

Stem cell technologies redefined

The physical parameters used in the study are reflective of the transient geometric constraints that cells can be exposed to in the body. For example, during development, the establishment of geometric patterns and niches are essential in the formation of functional tissues and organs. Similarly, when tissue is damaged, either through injury or disease, cells will experience sudden alterations to their environment. In each case, mature cells may revert back to a pluripotent, stem cell-like state, before being redeployed as specialised cells for the repair or maintenance of the tissue.

"While it is well established that confining stem cells to defined geometric patterns and substrate properties can direct their differentiation into specialised cells, this study shows for the first time that mechanical cues can reset the genomic programmes of mature cells and return them to a pluripotent state," Prof Shivashankar explained.

He added, "The use of geometric constraints to reprogramme mature cells may better reflect the process occurring naturally within the body. More importantly, our findings allow researchers to generate stem cells from mature cells with high efficiency and without genetically modifying them."
-end-
The team's research findings were published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) in May 2018.

National University of Singapore

Related Stem Cells Articles:

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.
First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.
Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.
The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.
Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.
New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.
NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.
Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.
In mice, stem cells seem to work in fighting obesity! What about stem cells in humans?
This release aims to summarize the available literature in regard to the effect of Mesenchymal Stem Cells transplantation on obesity and related comorbidities from the animal model.
TSRI researchers identify gene responsible for mesenchymal stem cells' stem-ness'
Researchers at The Scripps Research Institute recently published a study in the journal Cell Death and Differentiation identifying factors crucial to mesenchymal stem cell differentiation, providing insight into how these cells should be studied for clinical purposes.
More Stem Cells News and Stem Cells Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Dispatch 3: Shared Immunity
More than a million people have caught Covid-19, and tens of thousands have died. But thousands more have survived and recovered. A week or so ago (aka, what feels like ten years in corona time) producer Molly Webster learned that many of those survivors possess a kind of superpower: antibodies trained to fight the virus. Not only that, they might be able to pass this power on to the people who are sick with corona, and still in the fight. Today we have the story of an experimental treatment that's popping up all over the country: convalescent plasma transfusion, a century-old procedure that some say may become one of our best weapons against this devastating, new disease.   If you have recovered from Covid-19 and want to donate plasma, national and local donation registries are gearing up to collect blood.  To sign up with the American Red Cross, a national organization that works in local communities, head here.  To find out more about the The National COVID-19 Convalescent Plasma Project, which we spoke about in our episode, including information on clinical trials or plasma donation projects in your community, go here.  And if you are in the greater New York City area, and want to donate convalescent plasma, head over to the New York Blood Center to sign up. Or, register with specific NYC hospitals here.   If you are sick with Covid-19, and are interested in participating in a clinical trial, or are looking for a plasma donor match, check in with your local hospital, university, or blood center for more; you can also find more information on trials at The National COVID-19 Convalescent Plasma Project. And lastly, Tatiana Prowell's tweet that tipped us off is here. This episode was reported by Molly Webster and produced by Pat Walters. Special thanks to Drs. Evan Bloch and Tim Byun, as well as the Albert Einstein College of Medicine.  Support Radiolab today at Radiolab.org/donate.