Featured Research

from universities, journals, and other organizations

Adult cell self-renewal without stem cells?

Date:
November 23, 2009
Source:
CNRS (Délégation Paris Michel-Ange)
Summary:
Is the indefinite self-renewal of adult cells possible without recourse to stem cell intermediates? Scientists have shown that it is possible, by achieving the ex vivo regeneration of macrophages, specialized cells in the immune system, over several months.

Bacteria (in green) "eaten" by dividing macrophages.
Credit: Copyright M.Sieweke / CNRS

Is the indefinite expansion of adult cells possible without recourse to stem cell intermediates? The team led by Michael Sieweke at the Centre d'immunologie de Marseille Luminy (Université Aix-Marseille 2 / CNRS / INSERM) has shown that this is the case by achieving the ex vivo regeneration of macrophages, specialized cells in the immune system, over several months.

Published in Science on November 6, 2009, this discovery could be applied to other cell types. This research enables a clearer understanding of the mechanisms underlying cell differentiation, but above all raises many hopes for potential therapeutic applications.

The regenerative medicine of the future will be based on replacing damaged cells and repairing deficient organs, notably through the use of stem cells. Indeed, these cells are able not only to proliferate indefinitely but, in theory, to supply all types of cells to the human body. However, the processes that allow the passage from adult (rather than embryonic) cells to stem cells ("reprogramming") are complex and full of risk, as are the processes necessary for the "retransformation" of stem cells into adult cells. The question then arises: might it not be more simple to generate the cells required without passing through the stem cell stage?

Scientists at the Centre d'immunologie de Marseille Luminy (Université Aix-Marseille 2 / CNRS / INSERM) have studied a specific cell type: the macrophages(1). In most cases, when cells have acquired a specialized function (e.g. brain neurons, muscle cells, macrophages for the immune system, etc.) they cease to proliferate and normally remain "blocked" in this state until they die. Thus macrophages, which are key actors in the immune response, are usually incapable of proliferation. The team of CNRS and INSERM researchers led by Michael Sieweke has nonetheless been able to generate mouse macrophages in vitro thanks to a genetic modification that inactivates the transcription factors(2) called MafB and c-Maf. Furthermore, once reinjected into the animal, these modified cells behave normally: they do not form a tumor, and they perfectly perform the tasks expected of an adult macrophage, such as ingesting bacteria and secreting the chemical agents capable of killing them.

This CNRS and INSERM team in Marseilles has thus found how to re-initiate the division of specialized cells. In addition, they discovered that MafB and cMaf inactivation led to the activation of two of the four transcription factors (c-Myc and KLF4) recently identified as being able to convert almost all adult cells in the body into stem cells. Although this study provides a clearer understanding of the mechanisms of cell differentiation, above all it provides hope in the application of this method for the amplification of specialized cells to other cell types. These findings suggest that a passage via stem cells may not be necessary to enable the regeneration of cells and the repair of damaged tissue.

Notes:

(1) Macrophages are large cells that intervene in immune processes by destroying cell debris and microorganisms by means of a process called phagocytosis, an immune defense mechanism that notably allows macrophages to "eat" foreign particles such as bacteria, cell debris, dust particles, etc.

(2) Transcription factors are proteins that regulate the expression of genes by activating or inhibiting them. During embryonic development, cells diversify and specialize into different cell types; this is the process of cell differentiation.


Story Source:

The above story is based on materials provided by CNRS (Délégation Paris Michel-Ange). Note: Materials may be edited for content and length.


Journal Reference:

  1. Aziz et al. MafB/c-Maf Deficiency Enables Self-Renewal of Differentiated Functional Macrophages. Science, 2009; 326 (5954): 867 DOI: 10.1126/science.1176056

Cite This Page:

CNRS (Délégation Paris Michel-Ange). "Adult cell self-renewal without stem cells?." ScienceDaily. ScienceDaily, 23 November 2009. <www.sciencedaily.com/releases/2009/11/091116103838.htm>.
CNRS (Délégation Paris Michel-Ange). (2009, November 23). Adult cell self-renewal without stem cells?. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2009/11/091116103838.htm
CNRS (Délégation Paris Michel-Ange). "Adult cell self-renewal without stem cells?." ScienceDaily. www.sciencedaily.com/releases/2009/11/091116103838.htm (accessed October 22, 2014).

Share This



More Health & Medicine News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) — The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Vaccine Trials to Start a in January

WHO: Ebola Vaccine Trials to Start a in January

AP (Oct. 21, 2014) — Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe in soon to start trials, the World Health Organization said Tuesday. (Oct. 21) Video provided by AP
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) — A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) — The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So reports. Video provided by Reuters
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