Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discovery helps mice beat urinary tract infections

19.06.2012
Scientists at Washington University School of Medicine in St. Louis have found new clues to why some urinary tract infections recur persistently after multiple rounds of treatment.

Their research, conducted in mice, suggests that the bacteria that cause urinary tract infections take advantage of a cellular waste disposal system that normally helps fight invaders. In a counterintuitive finding, they learned that when the disposal system was disabled, the mice cleared urinary tract infections much more quickly and thoroughly.

"This could be the beginning of a paradigm shift in how we think about the relationship between this waste disposal system, known as autophagy, and disease-causing organisms," says senior author Indira Mysorekar, PhD, assistant professor of obstetrics and gynecology and of pathology and immunology. "There may be other persistent pathogens that have found ways to exploit autophagy, and that information will be very useful for identifying new treatments."

The results will be published the week of June 18, 2012, in the early online edition of The Proceedings of the National Academy of the Sciences.

Urinary tract infections are very common, particularly in women. In the United States alone, annual treatment costs are estimated to run as high as $1.6 billion. Scientists believe 80 percent to 90 percent of these infections are caused by the bacterium Escherichia coli (E. coli).

Data from the new study and earlier results have led Mysorekar and her colleagues to speculate that E. coli that cause recurrent urinary tract infections may hide in garbage-bin-like compartments within the cells that line the urinary tract.

These compartments, found in nearly all cells, are called autophagosomes. They sweep up debris within the cell, including harmful bacteria and worn-out cell parts. Then, they merge with other compartments in the cell that are filled with enzymes that break down the contents of autophagosomes.

"We think, but can't yet prove, that the bacteria have found a way to block this final step, " Myosrekar says. "This would transform the autophagosome from a death trap into a safe haven where the bacteria can wait, hidden from the immune system, for their next chance to start an infection."

In the new research, Mysorekar teamed with colleagues at the School of Medicine who had developed mice in which both copies of an important autophagy gene, Atg16L1, were impaired. Co-author Herbert W. Virgin, MD, PhD, Edward Mallinckrodt Professor and head of the Department of Pathology and Immunology, and others created the mice to study Crohn's disease, a chronic bowel inflammation associated with mutations in Atg16L1.

Co-lead authors Caihong Wang, DVM, PhD, a staff scientist, and Jane Symington, an MD/PhD student in the Mysorekar group, infected the mice with E. coli. The researchers found that bacteria levels in the urinary tracts of the modified mice decreased much more rapidly after infection than they did in normal mice. Cells lining the urinary tract in mice with the mutated gene also had significantly fewer dormant reservoirs of E. coli than in normal mice.

The scientists identified structural changes in urinary tract cells of the mice with Atg16L1 mutations that may help explain their unexpected results. These changes may have made it much more difficult for the bacteria to find and break into autophagosomes, Mysorekar says.

The altered gene also was associated with changes in the immune system. In the modified mice, E. coli infections in the urinary tract led cells to produce more inflammatory immune factors and prompted additional bacteria-fighting immune cells to come to the site of the infection.

"The immune system appears to be primed to attack at the slightest provocation in the mice with mutations," Mysorekar says. "This may be why mutations in Atg16L1 are also connected with Crohn's disease, which involves immune cells erroneously attacking beneficial microorganisms in the gut."

Mutations in Atg16L1 are quite common, according to Virgin, although not everyone who has a mutated form of the gene will get Crohn's disease.

"These new results may help explain why the mutations have persisted for so long in the general population," he says. "They don't just put the carrier at risk of Crohn's disease, they also may have a protective effect that helps fight infections."

Mysorekar plans to investigate how E. coli takes advantage of a fully functioning autophagy system in mice with urinary tract infections.

Wang C, Mendonsa GR, Symington JW, Zhang Q, Cadwell K, Virgin HW, Mysorekar IU. Atg16L1 deficiency confers protection from uropathogenic Escherichia coli infection in vivo. The Proceedings of the National Academy of Sciences, early online edition, week of June 18, 2012.

Funding from National Institute of Child Health and Human Development Grant T32-54560 (to G.R.M.), U54AI057160, Project 5 (to H.W.V.) and K99/R00 Pathway to Independence Award DK080643 (to I.U.M.) supported this research.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked sixth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Michael C. Purdy | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Routing gene therapy directly into the brain
07.12.2017 | Boston Children's Hospital

nachricht New Hope for Cancer Therapies: Targeted Monitoring may help Improve Tumor Treatment
01.12.2017 | Berliner Institut für Gesundheitsforschung / Berlin Institute of Health (BIH)

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

Im Focus: A transistor of graphene nanoribbons

Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."

Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

Blockchain is becoming more important in the energy market

05.12.2017 | Event News

 
Latest News

Making fuel out of thick air

08.12.2017 | Life Sciences

Rules for superconductivity mirrored in 'excitonic insulator'

08.12.2017 | Information Technology

Smartphone case offers blood glucose monitoring on the go

08.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>