Featured Research

from universities, journals, and other organizations

Notch signaling pathway keeps immature T cells on the right track

Date:
November 22, 2013
Source:
Perelman School of Medicine at the University of Pennsylvania
Summary:
One protein called Notch, which has well-known roles in the development of multiple tissues, plays an essential role in triggering T-cell development. Notch signaling induces expression of genes that promote the maturation of T cells and discourage alternative cell fates. Deficiency of the Notch target gene Hes1 in blood stem cells results in extremely low T-cell numbers, and could shed light on how normal cells are transformed in the context of cancer.

The lab of Avinash Bhandoola, PhD, professor of Pathology and Laboratory Medicine, has studied the origins of T cells for many years. One protein called Notch, which has well-known roles in the development of multiple tissues, plays an essential role in triggering T-cell development. T cells are immune cells that are made in the thymus, a small organ situated under the breastbone near the heart. However, T cells, like all blood-cell types, originate from blood-producing stem cells in the bone marrow. Immature T-cell progenitors leave the bone marrow, settle within the thymus, and eventually give rise to T cells.

With graduate student Maria Elena De Obaldia, Bhandoola describes in Nature Immunology this month how Notch signaling induces expression of genes that promote the maturation of T cells and discourage alternative cell fates. Deficiency of the Notch target gene Hes1 in blood stem cells results in extremely low T-cell numbers, but the underlying mechanism is unknown. Keeping in mind that Notch signaling gone awry induces leukemia, De Obaldia notes that "understanding the Notch pathway on a molecular level can shed light on how normal cells are transformed in the context of cancer."

The current study describes the mechanism of action of Hes1, a repressor protein that acts in the nucleus of immature T cells in the thymus. De Obaldia and Bhandoola found that Hes1 turns off genes such as C/EBPalpha, which promote the myeloid-cell fate and antagonize the T-cell fate. Whereas Hes1-deficient mice show severe T-cell defects, deleting the myeloid gene C/EBPalpha could restore normal T-cell development. This provided evidence that Hes1 keeps immature T cells on track by preventing them from defaulting to a myeloid developmental pathway, which controls non-lymphocyte cell maturation.

Because of this "policing" function, De Obaldia likens Hes1 to the traffic cop of T-cell development: "T-cell leukemias are addicted to Hes1, perhaps because it keeps progenitor cells on the path to producing more T cells, as opposed to myeloid cells. Bhandoola adds, "Our findings establish the importance of constraining myeloid developmental programs early in T-cell development, and this knowledge may provide clues about how to stop T-cell leukemias." Future studies will address whether Hes1 serves a similar function in Notch-dependent, T-cell leukemias by repressing myeloid genes, as it does during normal T-cell development.


Story Source:

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


Journal Reference:

  1. Maria Elena De Obaldia, J Jeremiah Bell, Xinxin Wang, Christelle Harly, Yumi Yashiro-Ohtani, Jonathan H DeLong, Daniel A Zlotoff, Dil Afroz Sultana, Warren S Pear, Avinash Bhandoola. T cell development requires constraint of the myeloid regulator C/EBP-α by the Notch target and transcriptional repressor Hes1. Nature Immunology, 2013; 14 (12): 1277 DOI: 10.1038/ni.2760

Cite This Page:

Perelman School of Medicine at the University of Pennsylvania. "Notch signaling pathway keeps immature T cells on the right track." ScienceDaily. ScienceDaily, 22 November 2013. <www.sciencedaily.com/releases/2013/11/131122165451.htm>.
Perelman School of Medicine at the University of Pennsylvania. (2013, November 22). Notch signaling pathway keeps immature T cells on the right track. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2013/11/131122165451.htm
Perelman School of Medicine at the University of Pennsylvania. "Notch signaling pathway keeps immature T cells on the right track." ScienceDaily. www.sciencedaily.com/releases/2013/11/131122165451.htm (accessed April 20, 2014).

Share This



More Health & Medicine News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. 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