Featured Research

from universities, journals, and other organizations

Fat clue to triggering latent tuberculosis

Date:
April 5, 2010
Source:
Society for General Microbiology
Summary:
The factors instrumental in triggering latent tuberculosis infection to progress into active disease have long remained elusive to researchers. New insight into the mystery is provided by research that could help develop innovative strategies for treating the disease.

Macrophages infected with Mycobacterium tuberculosis that have been transformed to express the red fluorescent protein (constitutively), and the green fluorescent protein in response to stress from low pH. The macrophages are loaded with a lysosomal tracer (cyan) The picture was taken shortly after infection when the bacteria are stressed and trying to establish the infection. These bacterial strains allow one to probe bacterial fitness during in vivo infections and to evaluate the efficacy of drug treatments and immune therapy.
Credit: Robert Abramovitch and David G. Russell

The factors instrumental in triggering latent tuberculosis (TB) infection to progress into active disease have long remained elusive to researchers. New insight into the mystery is provided by Professor David Russell, speaking at the Society for General Microbiology's spring meeting in Edinburgh. His work could help develop innovative strategies for treating the disease.

Professor Russell and his group at Cornell University in New York, USA, have demonstrated that TB-causing bacteria are able to hijack fat metabolism in the host to drive the progression of the disease. The team's research shows that Mycobacterium tuberculosis (Mtb) is able to stimulate macrophages -- the immune cells the bacterium infects -- to accumulate fat droplets, turning them into "foamy" cells. This cellular transformation can trigger a reawakening of the TB infection from its latent state.

Following initial infection by Mtb, the infected immune cells in the body can clump together in the lungs in a cellular mass that is surrounded by a fibrous cuff. This containing structure, called a tubercle, physically protects the bacteria from being destroyed by the immune system. This allows them to persist inside the host for years during a latent period in which the host shows no symptoms. The respiratory infection is reactivated only in a small percentage of individuals (often those who are immunosuppressed) in whom it progressively destroys lung tissue. Very little is known about the exact causes of reactivation and the relative roles of the host and the pathogen.

Professor Russell's group discovered that inside the tubercle, surface molecules of Mtb prompted host macrophage cells to take up vast quantities of cholesterol-type lipids from the surrounding blood vessels. "We think that the lipids in the newly-formed foamy cell are then expelled into the cellular environment, which contributes to the collapse of the tubercle," he said.

Once freed from their containing structure, the infectious bacteria are able to leak out into the airways where they can progressively destroy lung tissue. "If our model is correct, it has huge implications for vaccines and chemotherapy programmes. A more detailed knowledge of the bacterium's life cycle and its host interactions will allow us to spot new targets for drugs -- opening up new possibilities for treatment," said Professor Russell.


Story Source:

The above story is based on materials provided by Society for General Microbiology. Note: Materials may be edited for content and length.


Cite This Page:

Society for General Microbiology. "Fat clue to triggering latent tuberculosis." ScienceDaily. ScienceDaily, 5 April 2010. <www.sciencedaily.com/releases/2010/03/100329075917.htm>.
Society for General Microbiology. (2010, April 5). Fat clue to triggering latent tuberculosis. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2010/03/100329075917.htm
Society for General Microbiology. "Fat clue to triggering latent tuberculosis." ScienceDaily. www.sciencedaily.com/releases/2010/03/100329075917.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