Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stanford researchers isolate protein needed for stem cell maintenance

28.04.2003


Scientists have finally laid hands on the first member of a recalcitrant group of proteins called the Wnts two decades after their discovery. Important regulators of animal development, these proteins were suspected to have a role in keeping stem cells in their youthful, undifferentiated state - a suspicion that has proven correct, according to research carried out in two laboratories at Stanford University Medical Center. The ability to isolate Wnt proteins could help researchers grow some types of stem cells for use in bone marrow transplants or other therapies.



The gene coding for a protein usually reveals clues about how that protein will react in the lab and how best to isolate it from other molecules. The Wnts are unusual, however, because the way they behave in the lab differs from what the gene suggests. Roeland Nusse, PhD, professor of developmental biology at the School of Medicine and one of the first to isolate a Wnt (pronounced "wint") gene, reports how his lab members overcame these hurdles in the April 27 advance online edition of the journal Nature.

"We found that the protein is modified, explaining why it has been difficult to isolate," said Nusse, who is also an investigator at the Howard Hughes Medical Institute. Although the protein’s structure suggests it should dissolve easily in water, Karl Willert, PhD, a postdoctoral fellow in Nusse’s lab, found that an attached fat molecule makes the protein shun water and prefer the company of detergents instead.


With a Wnt in hand, researchers could finally confirm previous hints that the protein helps stem cells maintain their youthful state. This work, led by Irving Weissman, MD, the Karel and Avice Beekhuis Professor of Cancer Biology, involved cells in the bone marrow called hematopoietic stem cells that generate all blood cells throughout a person’s life. When these cells divide, some offspring go on to become red blood cells, immune cells and other blood components, while other offspring continue the stem cell line.

Experiments carried out by Tannishtha Reya, PhD, a former postdoctoral fellow in Weissman’s lab and now at Duke University, and graduate student Andrew Duncan showed that Wnt protein could cause hematopoietic stem cells to divide. After a week in an environment containing Wnt, mouse hematopoietic stem cells were about six times more likely to be dividing than cells grown in control conditions. What’s more, the majority of cells in the Wnt-containing environment were still stem cells, whereas their counterparts had blossomed into a potpourri of other blood cell types.

Additional experiments by Reya showed that other components of the Wnt pathway also trigger stem cell growth and that the pathway is required for stem cell maintenance. Reya describes these studies in a second Nature paper published alongside Nusse’s work.

"It’s a big deal to understand how these hematopoietic stem cells expand their numbers," Weissman said. With the ability to grow more stem cells in the lab, researchers would have a pool of cells available for research or potential therapies. Many molecules called growth factors cause stem cells to divide, but the new cells all go on to become other blood cell types.

"Whenever we would add these growth factors, at the end of the day we would have many different types of blood cells but no more stem cells than we started with," Weissman said.

The ability to grow hematopoietic stem cells would help doctors who need large numbers of these cells for use in bone marrow transplants. In Nusse’s paper, the researchers led by Reya reported that mouse hematopoietic stem cells grown in the presence of Wnt were better able to replenish the bone marrow of transplant recipients than stem cells grown without the protein.

In addition to the effects on hematopoietic stem cells, members of the Wnt family of proteins may nudge stem cells from other tissues to divide, making them easier to use in potential therapies. What’s more, knowing how stem cells self-renew could lead to ways of blocking self-renewal in the cancer stem cells that populate tumors. "We are now actively looking at whether any mouse or human cancers are using the Wnt pathway," Weissman said.



Additional Stanford researchers who participated in the work include Jeff Brown, PhD, a postdoctoral fellow; Esther Danenberg, a technician; and Laurie Ailles, a graduate student.

Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children’s Hospital at Stanford. For more information, please visit the Web site of the medical center’s Office of Communication & Public Affairs at http://mednews.stanford.edu.

Amy Adams | EurekAlert!
Further information:
http://mednews.stanford.edu
http://med-www.stanford.edu/MedCenter/MedSchool/

More articles from Life Sciences:

nachricht Rising water temperatures could endanger the mating of many fish species
03.07.2020 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Moss protein corrects genetic defects of other plants
03.07.2020 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

 
Latest News

Rising water temperatures could endanger the mating of many fish species

03.07.2020 | Life Sciences

Risk of infection with COVID-19 from singing: First results of aerosol study with the Bavarian Radio Chorus

03.07.2020 | Studies and Analyses

Efficient, Economical and Aesthetic: Researchers Build Electrodes from Leaves

03.07.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>