Nav: Home

Unraveling the mystery of stem cells

March 24, 2016

How do neurons become neurons? They all begin as stem cells, undifferentiated and with the potential to become any cell in the body.

Until now, however, exactly how that happens has been somewhat of a scientific mystery. New research conducted by UC Santa Barbara neuroscientists has deciphered some of the earliest changes that occur before stems cells transform into neurons and other cell types.

Working with human embryonic stems cells in petri dishes, postdoctoral fellow Jiwon Jang discovered a new pathway that plays a key role in cell differentiation. The findings appear in the journal Cell.

"Jiwon's discovery is very important because it gives us a fundamental understanding of the way stem cells work and the way they begin to undergo differentiation," said senior author Kenneth S. Kosik, the Harriman Professor of Neuroscience Research in UCSB's Department of Molecular, Cellular, and Developmental Biology. "It's a very fundamental piece of knowledge that had been missing in the field."

When stem cells begin to differentiate, they form precursors: neuroectoderms that have the potential to become brain cells, such as neurons; or mesendoderms, which ultimately become cells that comprise organs, muscles, blood and bone.

Jang discovered a number of steps along what he and Kosik labeled the PAN (Primary cilium, Autophagy Nrf2) axis. This newly identified pathway appears to determine a stem cell's final form.

"The PAN axis is a very important player in cell fate decisions," explained Jang. "G1 lengthening induces cilia protrusion and the longer those cellular antennae are exposed, the more signals they can pick up."

For some time, scientists have known about Gap 1 (G1), the first of four phases in the cell cycle, but they weren't clear about its role in stem cell differentiation. Jang's research demonstrates that in stem cells destined to become neurons, the lengthening phase of G1 triggers other actions that cause stem cells to morph into neuroectoderms.

During this elongated G1 interval, cells develop primary cilia, antennalike protrusions capable of sensing their environment. The cilia activate the cells' trash disposal system in a process known as autophagy.

Another important factor is Nrf2, which monitors cells for dangerous molecules such as free radicals -- a particularly important job for healthy cell formation.

"Nrf2 is like a guardian to the cell and makes sure the cell is functioning properly," said Kosik, co-director of the campus's Neuroscience Research Institute. "Nrf2 levels are very high in stem cells because stem cells are the future. Without Nrf2 watching out for the integrity of the genome, future progeny are in trouble."

Jang's work showed that levels of Nrf2 begin to decline during the elongated G1 interval. This is significant, Kosik noted, because Nrf2 doesn't usually diminish until the cell has already started to differentiate.

"We thought that, under the same conditions if the cells are identical, that both would differentiate the same way, but that is not what we found," Jang said. "Cell fate is controlled by G1 lengthening, which extends cilia's exposure to signals from their environment. That is one cool concept."
-end-


University of California - Santa Barbara

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

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.