Featured Research

from universities, journals, and other organizations

Cell and signaling pathway that regulates the placental blood stem cell niche identified

Date:
March 1, 2012
Source:
University of California, Los Angeles (UCLA), Health Sciences
Summary:
Stem cell researchers have discovered a critical placental niche cell and signaling pathway that prevent blood precursors from premature differentiation in the placenta, a process necessary for ensuring proper blood supply for an individual’s lifetime.

UCLA stem cell researchers have discovered a critical placental niche cell and signaling pathway that prevent blood precursors from premature differentiation in the placenta, a process necessary for ensuring proper blood supply for an individual's lifetime.

The placental niche, a stem cell "safe zone," supports blood stem cell generation and expansion without promoting differentiation into mature blood cells, allowing the establishment of a pool of precursor cells that provide blood cells for later fetal and post-natal life, said study senior author Dr. Hanna Mikkola, an associate professor of molecular cell and developmental biology and a researcher at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA.

Mikkola and her team found that PDGF-B signaling in trophoblasts, specialized cells of the placenta that facilitate embryo implantation and gas and nutrient exchanges between mother and fetus, is vital to maintaining the unique microenvironment needed for the blood precursors. When PDGF-B signaling is halted, the blood precursors differentiate prematurely, creating red blood cells in the placenta, Mikkola said.

The study, done in mouse models, appears March 1, 2012, in the peer-reviewed journal Developmental Cell.

"We had previously discovered that the placenta provides a home for a large supply of blood stem cells that are maintained in an undifferentiated state. We now found that, by switching off one signaling pathway, the blood precursors in the placenta start to differentiate into red blood cells," Mikkola said. "We learned that the trophoblasts act as powerful signaling centers that govern the niche safe zone."

The study found that the PDGF-B signaling in the trophoblasts is suppressing production of Erythropoietin (EPO), a cytokine that controls red blood cell differentiation.

"When PDGF-B signaling is lost, excessive amounts of EPO are produced in the placenta, which triggers differentiation of red blood cells in the placental vasculature," said Akanksha Chhabra, study first author and a post-doctoral fellow in Mikkola's lab.

Mikkola and Chhabra used mouse models in which the placental structure was disrupted so they could observe what cells and signaling pathways were important components of the niche.

"The idea was, if we mess up the home where the blood stem cells live, how do these cells respond to the altered environment," Chhabra said. "We found that it was important to suppress EPO where blood stem cell expansion is desired and to restrict its expression to areas where red blood cell differentiation should occur."

The finding, Chhabra said, was exciting in that one single molecular change "was enough to change the function of an important blood stem cell niche."

Mikkola said the blood stem cells expanded in the placental niche first seed the fetal liver and, ultimately, the bone marrow. The pool of blood stem cells could be compromised if the cells begin to differentiate in the placenta.

"We've been able to learn in the last few years about the niche cells in the adult bone marrow, but we didn't know much about them during fetal development," Mikkola said. "All hematopoietic niches in the embryo are unique in their own way, the stem cells are made in one location, expand in another and differentiate somewhere else. This is the first study that identifies a key niche cell and a signaling pathway in the placenta that allows it to do what it was destined to do, create a safe zone for the blood stem cells."

The three-year study was funded by the National Institutes of Health, the California Institute of Regenerative Medicine, an Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research Innovation Award and the Jonsson Cancer Center Foundation at UCLA.

"The discovery of PDGF-B signaling in the trophoblasts as an important regulator of local EPO levels in the placenta reveals a developmental stage and niche specific mechanism for regulating EPO expression, which is critical for governing the fates of blood stem cells during their developmental journey," the study states. "This work gives new insights into the goal of recreating the different types of hematopoietic niches in vitro as well as furthers our understanding of the etiology of developmental defects originating from the placenta."


Story Source:

The above story is based on materials provided by University of California, Los Angeles (UCLA), Health Sciences. The original article was written by Kim Irwin. Note: Materials may be edited for content and length.


Journal Reference:

  1. Akanksha Chhabra, Andrew J. Lechner, Masaya Ueno, Asha Acharya, Ben Van Handel, Yanling Wang, M. Luisa Iruela-Arispe, Michelle D. Tallquist, Hanna K.A. Mikkola. Trophoblasts Regulate the Placental Hematopoietic Niche through PDGF-B Signaling. Developmental Cell, 2012 DOI: 10.1016/j.devcel.2011.12.022

Cite This Page:

University of California, Los Angeles (UCLA), Health Sciences. "Cell and signaling pathway that regulates the placental blood stem cell niche identified." ScienceDaily. ScienceDaily, 1 March 2012. <www.sciencedaily.com/releases/2012/03/120301143312.htm>.
University of California, Los Angeles (UCLA), Health Sciences. (2012, March 1). Cell and signaling pathway that regulates the placental blood stem cell niche identified. ScienceDaily. Retrieved April 25, 2014 from www.sciencedaily.com/releases/2012/03/120301143312.htm
University of California, Los Angeles (UCLA), Health Sciences. "Cell and signaling pathway that regulates the placental blood stem cell niche identified." ScienceDaily. www.sciencedaily.com/releases/2012/03/120301143312.htm (accessed April 25, 2014).

Share This



More Health & Medicine News

Friday, April 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Companies Ramp Up Wellness to Lower Health Costs

Companies Ramp Up Wellness to Lower Health Costs

AP (Apr. 24, 2014) That little voice telling you to exercise, get in shape and get healthy is probably coming from your boss. More companies are beefing up wellness programs to try and cut down their health care costs. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
FDA Wants To Ban Sales Of E-Cigarettes To Minors

FDA Wants To Ban Sales Of E-Cigarettes To Minors

Newsy (Apr. 24, 2014) The Food and Drug Administration wants to crack down on the use of e-cigarettes, banning the sale of the product to minors. Video provided by Newsy
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:
from the past week

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