Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How Chlamydia gain access to human cells

31.10.2019

Publication in Nature Communications

Chlamydia are bacteria that can infect human and animal cells. Human health is particularly affected by Chlamydia pneumoniae (Cpn) and Chlamydia trachomatis. Chlamydia pneumoniae attacks the upper and lower respiratory tract and causes bronchitis, sinusitis and chest infections. Importantly, infections with this bacterium are associated with many chronic diseases such as chronic bronchitis, asthma, atherosclerosis and Alzheimer's disease.


A Chlamydia pneumoniae cell uses its surface protein LIPP (red) to bind to the outside of a human cell. The LIPP protein permeates the cell membrane and transports the cell's own phospholipid PS (green) from the interior to the exterior. Localisation of the PS molecule on the outer membrane leaflet helps the Chlamydium to enter the viable human cell. In the event of chlamydial infection, the PS on the outer membrane thus fulfils a different function than in dying human cells.

Credit: HHU / Jan Galle

Chlamydia multiply only inside of human cells. To do so, they first have to bind to the host cell from the outside and then enter the cell in a second step. Understanding these two mechanisms is one of the key research areas at the Institute of Functional Genome Research of Microorganisms headed up by Prof. Dr. Johannes Hegemann.

Each cell is surrounded by a membrane known as the 'plasma membrane'. This membrane comprises lots of individual molecules called 'phospholipids'. There are also membrane proteins, which are responsible for transporting materials between the cell interior and the outer environment as well as for intercellular communication. One component of the membrane is the phospholipid phosphatidylserine, or 'PS' for short. In healthy cells, it is located on the inner membrane leaflet, but if the cell is diseased, it is transported to the external membrane leaflet. Here, PS serves as a marker for programmed cell death (apoptosis).

In the working group of Prof. Hegemann, a protein called LIPP was discovered in Cpn that plays a key role in the binding of the bacterium to a human cell. This protein is located on the surface of the bacterium. In earlier studies, the researchers in Düsseldorf found that a chlamydial infection with Cpn is increased substantially if LIPP is added artificially.

This finding was the start of the present study.

One of their findings was that the LIPP protein binds directly to the plasma membrane and traverses the membrane after binding. Several LIPP molecules then form a pore in the plasma membrane.

Next, however, the bound LIPP transports the PS molecule, normally located on the inner membrane leaflet, to the outside. LIPP was the first protein to be identified that transports a component of the inner membrane leaflet to the surface of the cell when added externally. Surprisingly, this does not trigger cell death. Instead, the cell remains viable. This applies both to cells confronted only with the LIPP proteins and to those also infected with Chlamydia.

The research team proposes that it is beneficial for the Chlamydium to transport the PS molecule of the host cell outward using its LIPP protein. Possibly, at the place where the PS with the LIPP protein is located on the membrane, the membrane is so deformed that the Chlamydium can enter the cell more easily. It is also possible that the PS molecules transported to the outer membrane leaflet of the human cell serve as a receptor for the bacterium.

Dr. Jan Galle, first author of the study, had this to say about the prospects arising from these findings: "The LIPP protein has now become a possible target to prevent a chlamydial infection. If we succeed in coming up with a drug that restricts the function of the LIPP protein, it may be possible to prevent the infection." Likewise it is now possible to examine whether other pathogens have a tool similar to Chlamydia that they use to enter human cells. "If this were the case, it could form the basis for an extensive strategy against pathogenic bacteria," emphasises Prof. Hegemann.

###

Funding by the Jürgen Manchot Foundation and the SFB 1208

The LIPP protein was discovered as part of the research carried out in the "MOI - Molecules of Infection" Graduate School funded by the Jürgen Manchot Foundation and was further characterised within the framework of a Manchot PhD scholarship. This resulted in the sub-project A5 in the DFG-funded special research area 1208 "Identity and Dynamics of Membrane Systems" at HHU, where the key discoveries around the LIPP function were then made.

Original publication

Galle JN, Fechtner T, Eierhoff T, Römer W, Hegemann JH, A Chlamydia pneumoniae adhesin induces phosphatidylserine exposure on host cells, Nature Communications 2019 Oct 11;10(1):4644

DOI: 10.1038/s41467-019-12419-8

Media Contact

Dr. Arne Claussen
arne.claussen@hhu.de
49-021-181-10896

http://www.uni-duesseldorf.de/ 

Dr. Arne Claussen | EurekAlert!
Further information:
http://dx.doi.org/10.1038/s41467-019-12419-8

More articles from Life Sciences:

nachricht Programmable nests for cells
20.01.2020 | Karlsruher Institut für Technologie (KIT)

nachricht Obesity, heart disease or diabetes could be transmissible
20.01.2020 | Christian-Albrechts-Universität zu Kiel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Programmable nests for cells

KIT researchers develop novel composites of DNA, silica particles, and carbon nanotubes -- Properties can be tailored to various applications

Using DNA, smallest silica particles, and carbon nanotubes, researchers of Karlsruhe Institute of Technology (KIT) developed novel programmable materials....

Im Focus: Miniature double glazing: Material developed which is heat-insulating and heat-conducting at the same time

Styrofoam or copper - both materials have very different properties with regard to their ability to conduct heat. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the University of Bayreuth have now jointly developed and characterized a novel, extremely thin and transparent material that has different thermal conduction properties depending on the direction. While it can conduct heat extremely well in one direction, it shows good thermal insulation in the other direction.

Thermal insulation and thermal conduction play a crucial role in our everyday lives - from computer processors, where it is important to dissipate heat as...

Im Focus: Fraunhofer IAF establishes an application laboratory for quantum sensors

In order to advance the transfer of research developments from the field of quantum sensor technology into industrial applications, an application laboratory is being established at Fraunhofer IAF. This will enable interested companies and especially regional SMEs and start-ups to evaluate the innovation potential of quantum sensors for their specific requirements. Both the state of Baden-Württemberg and the Fraunhofer-Gesellschaft are supporting the four-year project with one million euros each.

The application laboratory is being set up as part of the Fraunhofer lighthouse project »QMag«, short for quantum magnetometry. In this project, researchers...

Im Focus: How Cells Assemble Their Skeleton

Researchers study the formation of microtubules

Microtubules, filamentous structures within the cell, are required for many important processes, including cell division and intracellular transport. A...

Im Focus: World Premiere in Zurich: Machine keeps human livers alive for one week outside of the body

Researchers from the University Hospital Zurich, ETH Zurich, Wyss Zurich and the University of Zurich have developed a machine that repairs injured human livers and keep them alive outside the body for one week. This breakthrough may increase the number of available organs for transplantation saving many lives of patients with severe liver diseases or cancer.

Until now, livers could be stored safely outside the body for only a few hours. With the novel perfusion technology, livers - and even injured livers - can now...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

„Advanced Battery Power“- Conference, Contributions are welcome!

07.01.2020 | Event News

 
Latest News

Molecules move faster on a rough terrain

20.01.2020 | Physics and Astronomy

Spider-Man-style robotic graspers defy gravity

20.01.2020 | Physics and Astronomy

Laser diode emits deep UV light

20.01.2020 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>