Featured Research

from universities, journals, and other organizations

Stem cells poised to self-destruct for the good of the embryo

Date:
May 3, 2012
Source:
University of North Carolina at Chapel Hill School of Medicine
Summary:
Embryonic stem cells are primed to kill themselves if damage to their DNA makes them a threat to the developing embryo. Researchers can reveal how they do it.

This is an image depicting active Bax (red) located at Golgi of human embryonic stem cells. Nuclei are stained in blue.
Credit: Deshmukh Lab, UNC-Chapel Hill

Embryonic stem cells -- those revered cells that give rise to every cell type in the body -- just got another badge of honor. If they suffer damage that makes them a threat to the developing embryo, they swiftly fall on their swords for the greater good, according to a study published online May 3, 2012 in the journal Molecular Cell.

The finding offers a new glimpse into the private lives of stem cells that could help scientists use them to grow new neurons or other cells to replace those that have been lost in patients with Parkinson's and other diseases. "Despite the huge potential of stem cells for therapeutic use, very few people have actually investigated their basic biology," said study senior researcher Mohanish Deshmukh, PhD, professor of cell and developmental biology at the University of North Carolina at Chapel Hill. "These results could have significant implications from a therapeutic perspective."

Of all the important things our bodies' cells do, staying alive is clearly key. But a cell's ability to die when something goes wrong is equally critical. For example, a faulty self-destruct button is one factor that allows cancer cells to proliferate unchecked and cause tumors.

Deshmukh and his colleagues discovered stem cells are extremely sensitive to DNA damage, which can be caused by factors like chemicals, radiation or viruses. The experiment showed that virtually 100 percent of human embryonic stem cells treated with a DNA-damaging drug killed themselves within 5 hours, as compared to 24 hours for other types of cells. "That's an incredibly rapid rate of death," said Deshmukh, who also is a member of the UNC Neuroscience Center and Lineberger Comprehensive Cancer Center.

The hair-trigger suicidal response is an important adaptation for embryonic stem cells, said the UNC School of Medicine researcher, because a slower response could allow DNA damage to proliferate and harm the embryo. "Mutations that develop in these cells could be catastrophic for the developing organism, so it would make sense for these cells to be rapidly eliminated."

The key to the stem cells' quick response is that they pre-activate a critical protein called Bax, the researchers found. In most cells, Bax is is kept in an inactive form, waiting for a long chain of events to rouse it into action if the cell becomes damaged enough to kill itself. In human embryonic stem cells, the team found Bax standing at attention in its active form in the Golgi apparatus, a part of the cell that processes and modifies proteins.

"What these cells do is very clever," said Deshmukh. "They have activated Bax, but they've also parked it in a safe little compartment -- the Golgi." If the cell detects DNA damage, Bax zips over to the mitochondrion (the cell's power plant), where it signals other proteins to shut the cell down.

It's like starting a 100-yard race at the 80-yard line, said Deshmukh. You're guaranteed to get to the finish line first because you did most of the work before the race began. However, there are built-in safeguards against a hair trigger activation of death. Pre-activated Bax is housed in the Golgi keeping the protein from accidentally triggering cell death when it's not warranted.

This extreme sensitivity to DNA damage lasts only a few days during early development. After the embryonic stem cells begin differentiating into early progenitors that give rise to specific cell types (like heart cells or skin cells), Bax reverts to its inactive state.

UNC Co-first authors of this study are -- Raluca Dumitru and Vivian Gama. Other UNC Co-authors include B. Matthew Fagan, Jacquelyn J Bower, Vijay Swahari and Larysa H Pevny. The study was funded by grants from the National Institutes of Health (National Institute of General Medical Sciences) and UNC's University Cancer Research Fund.


Story Source:

The above story is based on materials provided by University of North Carolina at Chapel Hill School of Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Raluca Dumitru, Vivian Gama, B.Matthew Fagan, JacquelynJ. Bower, Vijay Swahari, LarysaH. Pevny, Mohanish Deshmukh. Human Embryonic Stem Cells Have Constitutively Active Bax at the Golgi and Are Primed to Undergo Rapid Apoptosis. Molecular Cell, 2012; DOI: 10.1016/j.molcel.2012.04.002

Cite This Page:

University of North Carolina at Chapel Hill School of Medicine. "Stem cells poised to self-destruct for the good of the embryo." ScienceDaily. ScienceDaily, 3 May 2012. <www.sciencedaily.com/releases/2012/05/120503125645.htm>.
University of North Carolina at Chapel Hill School of Medicine. (2012, May 3). Stem cells poised to self-destruct for the good of the embryo. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2012/05/120503125645.htm
University of North Carolina at Chapel Hill School of Medicine. "Stem cells poised to self-destruct for the good of the embryo." ScienceDaily. www.sciencedaily.com/releases/2012/05/120503125645.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Liberia Pleads for Help to Fight Ebola

Liberia Pleads for Help to Fight Ebola

AP (Sep. 22, 2014) Liberia's finance minister is urging the international community to quickly follow through on pledges of cash to battle Ebola. Bodies are piling up in the capital Monrovia as the nation awaits more help. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Ebola Doctor Says Border Controls Critical

Ebola Doctor Says Border Controls Critical

AP (Sep. 22, 2014) A Florida doctor who helped fight the expanding Ebola outbreak in West Africa says the disease can be stopped, but only if nations quickly step up their response and make border control a priority. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Global Ebola Aid Increasing But Critics Say It's Late

Global Ebola Aid Increasing But Critics Say It's Late

Newsy (Sep. 21, 2014) More than 100 tons of medical supplies were sent to West Africa on Saturday, but aid workers say the global response is still sluggish. Video provided by Newsy
Powered by NewsLook.com
Sierra Leone in Lockdown to Control Ebola

Sierra Leone in Lockdown to Control Ebola

AP (Sep. 21, 2014) Sierra Leone residents remained in lockdown on Saturday as part of a massive effort to confine millions of people to their homes in a bid to stem the biggest Ebola outbreak in history. (Sept. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins