The study proposed a new model to explain how mammalian cells establish the sense of direction necessary to move, as well as the mechanism that a disease-causing form of E. coli bacteria employ to hijack that ability. Cells need to orient themselves for several basic processes, such as keeping biochemical reactions separated in space and, in the case of immune cells, pursuing pathogens. Importantly, disruption of the cell's sense of direction often leads to human disease.
"This is a great example of scientists from different fields of research coming together to solve a complex and important biological problem," said Dr. Neal Alto, assistant professor of microbiology and senior author of the study, published Feb. 17 in Cell.
Systems biology aims to discover and understand a "circuit theory" for biology – a set of powerful and predictive principles that will reveal how networks of biological components are wired to display the complex properties of living things. The rapidly emerging field requires experts in several scientific disciplines – including biology, physics, mathematics and computer science – to come together to create models of biological systems that consider both the individual parts and how these parts react to each other and to changes in their environment.
Scientists from UT Southwestern's microbiology department and the newly expanded Cecil H. and Ida Green Comprehensive Center for Molecular, Computational and Systems Biology teamed up to examine the problem collaboratively. They initially conceived a mathematical model for their hypothesis of how the cell would respond during an E. coli-induced infection and then tested their computational predictions in living cells.
"Bacteria inject protein molecules into human cells with a needle-and-syringe action," Dr. Alto said. "The human cell responds by producing a local actin-rich membrane protrusion at the spot where the bacteria attaches to the cell."
For healthy cells to move normally, these actin polymers push against a cell's membrane, protruding and propelling the cell in one direction or another. When E. coli molecules are injected, however, actin polymers rush to the site infection and help bacterial molecules both move within the cell and establish an internal site of infection.
Robert Orchard, graduate student of microbiology and the study's lead author, said: "By asking 'How does a bacterial pathogen from outside the cell regulate the host cells' actin dynamics within the cell?' we have uncovered a fundamentally new molecular circuit involved in mammalian cell polarity and bacterial infection. These findings provide new insight into the regulatory mechanisms that control both disease-causing agents and normal mammalian cell behavior."
Other UT Southwestern researchers from the Green Center involved in the work were Dr. Steven Altschuler and Dr. Lani Wu, both associate professors of pharmacology; Dr. Gürol Süel, assistant professor of pharmacology; and Mark Kittisopikul, a student in the Medical Scientist Training Program.
The National Institutes of Health, the James S. McDonnell Foundation and The Welch Foundation supported the study. The researchers also received assistance from the UT Southwestern Live Cell Imaging Facility, which is supported in part by the National Cancer Institute.
This news release is available on our World Wide Web home page at www.utsouthwestern.edu/home/news/index.html
To automatically receive news releases from UT Southwestern via email, subscribe at www.utsouthwestern.edu/receivenews
Deborah Wormser | EurekAlert!
Cnidarians remotely control bacteria
21.09.2017 | Christian-Albrechts-Universität zu Kiel
Immune cells may heal bleeding brain after strokes
21.09.2017 | NIH/National Institute of Neurological Disorders and Stroke
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine