Navigation Links
UC Davis researchers discover molecular target for the bacterial infection brucellosis
Date:8/15/2013

(SACRAMENTO, Calif.) UC Davis scientists have uncovered a potential drug target for the development of an effective therapy against the debilitating, chronic form of the bacterial disease brucellosis, which primarily afflicts people in Mediterranean and Middle Eastern countries.

Brucellosis, which affects about 500,000 people worldwide each year, typically is caused by ingestion of unsterilized milk or close contact with body secretions from infected animals. Symptoms include intermittent or irregular fever of variable duration, headache, weakness, profuse sweating, chills, weight loss and generalized aching. It can also cause long-lasting or chronic symptoms such as recurrent fevers, joint pain and fatigue.

In a paper published online this week in the journal Cell Host & Microbe, the researchers reported that they have identified the cells that harbor the B. abortus bacteria during the persistent phase of the brucellosis. The cells, known as alternatively activated macrophages (AAMs), are a recently identified category of immune defense cells.

The researchers also determined that the biological pathway peroxisome proliferator activated receptor γ, abbreviated as PPARγ, is responsible for altering the metabolism of AAMs so that they supply B. abortus with the energy in the form of glucose that enables bacteria to survive and replicate and thereby sustain the chronic phase of the infectious disease. Other labs also have shown that PPARγ control a cell's metabolism.

"We found that PPARγ induces a metabolic shift in these cells that causes them to generate glucose," said Renee Tsolis, associate professor of medical microbiology and immunology at UC Davis who led the study.

"Starving the B. abortus bacteria by inhibiting the PPARγ pathway may be a new approach to eradicating the chronic, difficult-to-treat form of Brucellosis infection that usually occurs because antibiotic therapy was not used during the acute, or early, phase of the infection," said Tsolis.

Tsolis and her collaborators were the first to discover PPARγ's role in brucellosis and to determine that AAMs harbor the bacteria during the chronic stage of the disease. The identification of the bacteria's niche is another important clue for the development of a more effective treatment, she said.

In a series of experiments, Tsolis and collaborators found that the gene encoding PPARγ is very active during chronic Brucellosis infection, but not during acute infection, and that the B. abortus bacteria did not survive in AAMs when deprived of glucose.

When the researchers inactivated the protein that normally transports glucose, the bacteria stopped reproducing, and the infection no longer was chronic, she said.

In mice infected with B. abortus, Tsolis and collaborators treated the animals with GW9662, a PPAR inhibitor. The researchers administered the inhibitor before the infection became chronic, or long lasting. The inhibitor significantly reduced the amount of AAMs and B. abortus bacteria in the mice.

"These results suggested that inhibition of PPARreduced the bacteria's survival by reducing the abundance of AAMs during chronic infection," said Tsolis.

Conversely, when the researchers treated the B. abortus-infected mice with Rosiglitazone, a drug that boosts PPAR activity, the bacteria increased by two-fold during the acute phase and four-fold during the chronic phase of infection. Rosiglitazone and other drugs that boost PPARare used to treat type 2 diabetes because they lower blood glucose by increasing cellular glucose uptake.

In other experiments, the researchers showed that AAMs, one of two categories of macrophages, are abundant in the spleen during chronic brucellosis but not during the acute, or initial, phase of the infection, which is dominated by classically activated macrophages (CAM), the second category of these immune cells.

In addition to profuse sweating, symptoms of brucellosis infection include joint and muscle pain. Among the complications of chronic infection are arthritis and endocarditis, a serious inflammation of one of the four heart valves. Brucellosis rarely occurs in the U.S., with about 100 to 200 cases reported each year, according to the U.S. Centers for Disease Control and Prevention.


'/>"/>

Contact: Carole Gan
carole.gan@ucdmc.ucdavis.edu
916-734-9047
University of California - Davis Health System
Source:Eurekalert

Related biology news :

1. UC Davis study deflates notion that pear-shaped bodies more healthy than apples
2. UC Davis researchers aid effort to sequence the complex wheat genome
3. UC Davis researchers develop new drug delivery system for bladder cancer using nanoparticles
4. UC Davis study finds that above-normal weight alone does not increase the short-term risk of death
5. UC Davis scientists find new role for P53 genetic mutation -- initiation of prostate cancer
6. Researchers report a critical role for the complement system in early macular degeneration
7. Researchers study seleniums effects on horses
8. Researchers discover protein that helps plants tolerate drought, flooding, other stresses
9. Fresh analysis of dinosaur skulls by penn researchers finds 3 species are 1
10. HSCI researchers extend human epigenomic map
11. Researchers re-evaluate swine nutrition
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/2/2016)... , Feb. 2, 2016 Technology Enhancements Accelerate Growth ... analysis of the digital and computed radiography markets in ... , and Indonesia (TIM). It ... market size, as well as regional market drivers and ... discusses market penetration and market attractiveness, both for digital ...
(Date:2/1/2016)... , Feb. 1, 2016  Wocket® smart wallet ( www.wocketwallet.com ) announces ... personality, Joey Fatone . Las Vegas , ... --> Las Vegas , where Joey appeared ... The new video ad was filmed at the Consumer Electronics Show ... the Wocket booth to meet and greet fans. ...
(Date:1/22/2016)... 22, 2016 ... of the  "Global Behavioral Biometric Market ... --> http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) has announced ... Biometric Market 2016-2020"  report to their ... Markets ( http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) has announced the ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... 11, 2016  Vermillion, Inc. (NASDAQ: VRML ), ... announced the formation of the Steering Committee for its ... --> Pelvic masses can present physicians and ... Once pregnancy is ruled out, pelvic masses may include ... endometriosis, benign ovarian tumors and gastrointestinal and urinary tract ...
(Date:2/11/2016)... -- Wellcentive today announced it has been selected by FamilyCare ... community care organization (CCO) with more than 130,000 ... and care management solutions and services. Wellcentive,s capabilities ... managers, analysts and care managers while providing insight ... members. Oregon . ...
(Date:2/11/2016)... Feb. 11, 2016   BioInformant announces the ... Cell Research Products, Opportunities, Tools, and Technologies – Market ... The first ... stem cell industry, BioInformant has more than a decade ... cell market, by stem cell type. This powerful 175 ...
(Date:2/10/2016)... MONTREAL , Febr. 10, 2016 /PRNewswire/ - BioAmber Inc. ... is pleased to announce that Mitsui & Co. Ltd., ... bio-based succinic acid plant, is investing an additional CDN$25 ... equity, increasing its stake from 30% to 40%.  Mitsui ... of bio-succinic acid produced in Sarnia ...
Breaking Biology Technology: