Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chlamydia: How bacteria take over control

28.03.2017

To survive in human cells, chlamydiae have a lot of tricks in store. Researchers of the University of Würzburg have now discovered that the bacterial pathogens also manipulate the cells' energy suppliers in the process.

When Chlamydia trachomatis infects a human cell, it faces a huge challenge: It must prevent the cell from triggering programmed cell death to prevent the bacteria from replicating and spreading throughout the body.


Zwei Zellen, links nach einer Infektion mit Chlamydia-Bakterien, rechts ohne. Obwohl beide Zellen mit einer Substanz behandelt wurden, die das mitochondriale Netzwerk zerstört, bleibt das Netzwerk in der infizierten Zelle intakt. (Abbildung: Suvagata Roy Chowdhury)

Since numerous metabolic processes are either missing or fragmented in the pathogen, it is reliant on the host cell to supply the vital nutrients on a permanent basis.

Research projects worldwide focus on how the bacteria manage to keep the cell alive and working for it. Scientists from the University of Würzburg have now uncovered a new detail of these processes.

They identified a mechanism with which Chlamydia trachomatis influences the mitochondria, the cells' power plants, thereby preventing the cells from committing suicide. In the scientific journal Journal of Cell Biology, the scientists present the results of their work.

The role of mitochondria

The study was led by Professor Thomas Rudel, who holds the Chair of Microbiology at the University of Würzburg. Already three years ago, Rudel and his team showed that chlamydiae disable the tumour suppressor protein p53 in infected cells and initiate a process which repairs DNA damages resulting from chlamydia infection. By blocking p53, the bacteria prevent the cell from knocking itself out in the worst case, thereby winning time for replication.

In their new study, the microbiologists took a closer look at the mitochondria. "Mitochondria play a crucial role in energy supply and programmed cell death," Thomas Rudel explains. He sees strong evidence that changes in their architecture and dynamics are closely related to the cells' general metabolic processes.

Focus on small RNA molecules

What impact does a chlamydia infection have on mitochondria? To answer this question, Rudel's team scrutinized another actor in the goings-on inside cells: the so-called miRNAs or microRNAs. These small RNA molecules control vital processes inside cells by regulating complex networks of genes.

High-throughput sequencing allowed Rudel and his team to study in depth how a chlamydia infection impacts the miRNA expression of the infected cell. The most striking finding is a greatly increased production of the miR-30c-5p microRNA. A high concentration of these tiny RNA molecules is beneficial for the bacteria: "They cause the tumour suppressor protein to be downregulated permanently," Thomas Rudel explains.

In return, blocking miR-30c causes the chlamydia trouble, because the cell increases its production of Drp1, a protein that fragments the mitochondria in cells under stress. As its concentration inside cells increases, so does the stress-related mitochondrial division rate while the infected cell's chances of surviving the bacterial attack improve. This is because chlamydial growth is inhibited significantly by the fragmented mitochondria that supply less energy and starve the pathogens.

Chlamydia: Resourceful invaders

Bacteria of the strain Chlamydia trachomatis are responsible for a number of serious diseases in humans. Chlamydia infections are the most frequent sexually transmitted diseases worldwide. Up to ten percent of the population worldwide are estimated to be infected with the bacteria depending on the age group.

Untreated, chlamydia infection can cause fallopian tubes blockage in women which can result in tubal pregnancy or infertility. Newer findings even suggest that chlamydia infections promote ovarian cancer. Men can become infertile after an infection.

Another consequence of chlamydia infection occurs especially in tropical countries: The bacteria infect the eyes and may cause blindness. It is estimated that around 150 million people are affected by the disease. Other strains may trigger pneumonia and are suspected to cause arteriosclerosis and Alzheimer's.

Chlamydia preserves the mitochondrial network necessary for replication via microRNA-dependent inhibition of fission. Suvagata Roy Chowdhury, Anastasija Reimer, Malvika Sharan, Vera Kozjak Pavlovic, Ana Eulalio, Bhupesh K. Prusty, Martin Fraunholz, Karthika Karunakaran, and Thomas Rudel The Journal of Cell Biology. https://doi.org/10.1083/jcb.201608063

Contact

Prof. Dr. Thomas Rudel, Department of Microbiology, T +49 931 31-84401, Thomas.Rudel@biozentrum.uni-wuerzburg.de

Gunnar Bartsch | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-wuerzburg.de

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

NSF-supported researchers to present new results on hurricanes and other extreme events

19.07.2018 | Earth Sciences

Scientists uncover the role of a protein in production & survival of myelin-forming cells

19.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>