Featured Research

from universities, journals, and other organizations

Trio Of Signals Converge To Induce Liver And Pancreas Cell Development In The Embryo

Date:
July 7, 2009
Source:
University of Pennsylvania School of Medicine
Summary:
Understanding the molecular signals that guide early cells in the embryo to develop into different organs provides insight into ways that tissues regenerate and how stem cells can be used for new therapies. Researchers have investigated a trio of cell-signaling pathways that work simultaneously, converging to direct pancreas and liver progenitor cells to mature into their final state.

Distribution of the genetic regulatory protein, Smad4, in a mouse embryo at 8.5 days gestation. The green stain in the center is Smad4 expressed in the liver and pancreas progenitor cells. The green on the periphery is Smad4 in the extraembryonic yolk sac tissue.
Credit: Ken Zaret, PhD; Ewa Wandzioch, PhD, University of Pennsylvania School of Medicine

Understanding the molecular signals that guide early cells in the embryo to develop into different organs provides insight into ways that tissues regenerate and how stem cells can be used for new therapies. With regenerated cells, researchers hope to one day fill the acute shortage in pancreatic and liver tissue available for transplantation in cases of type I diabetes and acute liver failure.

Related Articles


Previous studies on pancreas and liver development have focused on individual molecular signals that induce these tissues to mature from a common precursor cell population. In a new study, published this week in Science, researchers investigated a trio of cell-signaling pathways that work simultaneously, converging to direct pancreas and liver progenitor cells to mature into their final state. They looked at how BMP, TGF-beta, and FGF signaling pathways turn on genes that guide cells to ultimately become pancreas or liver tissue.

The structure of the cell-signaling network provides insight into the basis of tissue development and how it can be manipulated to facilitate pancreas and liver-cell regeneration and development from embryonic stem cells.

“For my entire scientific life, I've been intrigued by how cells early in development make ‘decisions’ to turn on one genetic program and exclude others,” says Kenneth S. Zaret, PhD, Professor of Cell and Developmental Biology and Associate Director at the Institute for Regenerative Medicine at the University of Pennsylvania School of Medicine.

The work was conducted while Zaret and co-author Ewa Wandzioch, PhD, Research Associate in the Department of Cell and Developmental Biology, were at the Fox Chase Cancer Center in Philadelphia.

How the developing embryo starts to apportion different functions to different cell types is a key question for developmental biology and regenerative medicine.

Guidance along the correct path is provided by genetic regulatory proteins that attach to chromosomes, marking part of the genome to be turned on or off. But first the two meters of tightly coiled DNA inside the nucleus of every cell must be loosened a bit. The regulatory proteins help with this, exposing a small domain near the target gene. They then act as a landing pad on which other proteins assemble to continue the gene activation process.

The Science paper addresses how chemical signals from neighboring cells in the embryo tell early progenitor cells to activate genes encoding the regulatory proteins. The regulatory proteins, in turn, guide the cells to become a liver cell or a pancreas cell. “In the current study we mapped the signaling pathways being turned on before they connected with the target genes,” explains Zaret. “We monitored these cues before the cell displayed any overt signs of differentiation. While my lab and others had previously looked at individual signals that influence development, in this paper we simultaneously mapped three signal paths that converge to induce liver and pancreas cells. We’re starting to construct a network of the common signals that govern development of these specific cell types. The complexity of this system is somewhat like our 26-letter alphabet being able to encode Shakespeare or a menu at a restaurant.”

Many investigators are now trying to broadly reprogram cells into desired cell fates for potential therapeutic uses. “By better understanding how a cell is normally programmed we will eventually be able to directly reprogram other cells,” notes Zaret. “An analogy I use here is if a watch is broken and you want to know how to reassemble it, the best thing is to go the factory and see how it is assembled in the first place. That may not be the solution to fixing it, but it's a good place to start.”

In the near term, the team also aims to generate liver and pancreas cells for research and to screen drugs that repair defects or facilitate cell growth.

The work was funded by the National Institutes of Health, including the Institute of General Medical Sciences and the Institutes for Diabetes, Digestive, and Kidney Disorders.


Story Source:

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


Cite This Page:

University of Pennsylvania School of Medicine. "Trio Of Signals Converge To Induce Liver And Pancreas Cell Development In The Embryo." ScienceDaily. ScienceDaily, 7 July 2009. <www.sciencedaily.com/releases/2009/06/090626141229.htm>.
University of Pennsylvania School of Medicine. (2009, July 7). Trio Of Signals Converge To Induce Liver And Pancreas Cell Development In The Embryo. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2009/06/090626141229.htm
University of Pennsylvania School of Medicine. "Trio Of Signals Converge To Induce Liver And Pancreas Cell Development In The Embryo." ScienceDaily. www.sciencedaily.com/releases/2009/06/090626141229.htm (accessed March 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, March 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) — Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
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