Their results are described online in the Proceedings of the National Academy of Sciences.
Neutrophils are white blood cells that are activated by chemical cues to move quickly to the site of injury or infection, where they ingest bacteria. When alerted to infection, neutrophils move by changing shape, developing a distinct front and back, sending a "foot" out in front of them, and "crawling" toward the site of infection.
Hoping to better understand the role of a protein called p55 or MPPI that they had previously identified as highly expressed in neutrophils, the UIC researchers bred the first mice that completely lacked this protein.
The "knockout" mice had marked difficulty fighting infection and were slow to heal, according to Athar Chishti, professor of pharmacology and principal investigator in the study.
Instead of forming a single large pseudopod, or foot-like extension, in the direction of the infection, neutrophils from the knockout mice formed a number of small extensions all around the cell, said Chishti.
Neutrophils lacking p55 would follow a meandering path, wandering in circles. "It was as though the neutrophils had lost their sense of direction," said Brendan Quinn, graduate assistant researcher in pharmacology and first author of the study.
Neutrophils are part of the body's innate immunity and its first line of defense, so the speed of the response is key to healing. "The neutrophils eventually get to the infection site, but they would get there late," Quinn said.
The researchers also established how p55 wields its effect on neutrophils, demonstrating that although the cell's ability to reorganize its actin skeleton to produce pseudopods was undisturbed, a signaling lipid known to be important in establishing polarity, called PIP3, failed to localize on the leading edge of the p55-null neutrophils, instead diffusing throughout the cell.
Further, the p55-null neutrophils had a marked reduced activation of another important signaling protein, Akt, which is believed to play an important role in many cancers.
"This study offers clues to an important cell signaling pathway that is critical to cellular polarization processes in neutrophils and many other cells," said Chishti.
Emily J. Welch, Anthony C. Kim, Anwar A. Khan and Shafi M Kuchay of the department of pharmacology at the UIC College of Medicine and Mary A. Lokuta and Anna Huttenlocher of the departments of pediatrics and pharmacology at the University of Wisconsin, Madison, also contributed to the study. The work was funded by grants from the National Institutes of Health and the Department of Defense Neurofibromatosis Research Program Career Development Award.
Jeanne Galatzer-Levy | EurekAlert!
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy