Forum for Science, Industry and Business

Team discovers how a cancer-causing bacterium spurs cell death

H. pylori are the only bacteria known to survive in the human stomach.

Infection with the bacterium is associated with an increased risk of gastric cancer, the second-leading cause of cancer-related deaths worldwide.

“More than half the world’s population is currently infected with H. pylori,” said University of Illinois microbiology professor Steven Blanke, who led the study. “And we’ve known for a long time that the host doesn’t respond appropriately to clear the infection from the stomach, allowing the bacterium to persist as a risk factor for cancer.”

The new study, in Proceedings of the National Academy of Sciences, is the first to show how a bacterial toxin can disrupt a cell’s mitochondria – its energy-generation and distribution system – to disable the cell and spur apoptosis (programmed cell death).

“One of the hallmarks of long-term infection with H. pylori is an increase in apoptotic cells,” Blanke said. “This may contribute to the development of cancer in several ways.” Apoptosis can damage the epithelial cells that line the stomach, he said, “and chronic damage to any tissue is a risk factor for cancer.” An increase in apoptotic cells may also spur the hyper-proliferation of stem cells in an attempt to repair the damaged tissue, increasing the chance of mutations that can lead to cancer.

The VacA protein was known to target the mitochondrion, an organelle that produces chemical energy where it is needed in the cell. In healthy cells, mitochondria fuse to form elaborate energy-generating networks in response to cellular needs. Mitochondria are important to a lot of other cellular processes; most important to Blanke and his colleagues, they regulate cell death.

While studying how a cell responds to infection, the researchers noticed that H. pylori induced mitochondrial fission. Instead of fusing and forming filamentous networks to respond to the cell’s energy needs, the mitochondria were breaking into smaller, unconnected organelles.

“Fusion and fission are two dynamic and opposing processes that must be balanced to regulate mitochondrial structure and function,” Blanke said. But infection with H. pylori – or with purified VacA toxin alone – was pushing the mitochondria toward fission.

“The link between VacA action at the mitochondria and Bax-dependent cell death had previously been unknown,” Blanke said.

This study provides a first direct link between a bacterial toxin-mediated disruption of mitochondrial dynamics and host cell death, Blanke said. It also opens a new avenue of investigation of other diseases linked to impaired mitochondrial function, he said.

“Hundreds of human diseases and disorders are associated with mitochondrial dysfunction, ranging from cancers to degenerative diseases such as Alzheimer’s disease and Parkinson’s,” Blanke said. “As yet, no one has methodically investigated a potential link between bacterial infections and mitochondrial diseases, despite the fact that several dozen pathogenic bacteria and viruses are known to directly target mitochondria.”

Blanke and his colleagues are beginning to investigate that link.

“To us, finding that a pathogen can disrupt mitochondria in a manner that has striking similarities to what has been observed in known mitochondrial diseases is potentially very exciting,” said Blanke, who also is an affiliate of the Institute for Genomic Biology at Illinois.

Diana Yates | University of Illinois
Further information:
http://www.illinois.edu

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...