Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers find a potential key to human immune suppression in space

13.10.2005


Artificial microgravity causes suppression of 99 key immune genes, leading to T-cell suppression



Researchers at the San Francisco VA Medical Center have identified a set of key immune-response genes that do not turn on in a weightless environment. The discovery is another clue in the effort to solve an almost 40-year-old mystery: why the human immune system does not function well in the weightlessness of space.

The researchers, led by SFVAMC biochemist and former astronaut Millie Hughes-Fulford, PhD, identified a signaling pathway called PKA that in a gravity field responds to the presence of a pathogen by stimulating the expression of 99 genes that in turn cause the activation of T-cells, which are essential for proper immune function.


Hughes-Fulford found that in the simulated absence of gravity, the PKA pathway did not respond to the pathogen’s presence; as a result, 91 genes were not induced and eight genes were significantly inhibited, severely reducing the activation of T-cells. The paper was published on October 6 in FJ Express, the online rapid-publication section of the Journal of the Federation of American Societies for Experimental Biology.

"This is a specific signal pathway that is not working in the absence of gravity," says Hughes-Fulford, who is also an adjunct professor of medicine at the University of California, San Francisco. "You’re short-circuiting a whole lot of the immune response -- namely, the ability to proliferate T-cells -- which shouldn’t be a surprise, because life evolved in Earth’s gravity field."

Hughes-Fulford points out that there are only two known situations in which T-cell function is so severely compromised: HIV infection and weightlessness.

The research was conducted on human immune cells in culture that were placed in a device called a random positioning machine, which simulates freefall.

The researchers found that three other pathways which regulate immune function -- P13K, PKC, and pLAT -- were not affected by the absence of gravity.

"Why do some pathways work and some not? Perhaps it’s differences in the cytoskeleton – the interior architecture of the cell," speculates Hughes-Fulford. "It’s the infrastructure of the cell, a membrane made of lipid, and maybe without gravity it’s not as well-organized as it should be."

Human immune suppression in space was first observed in the 1960s and 70s during the Apollo missions conducted by the United States. As the researchers note in their paper, "15 of 29 Apollo astronauts reported a bacterial or viral infection during [a mission], immediately after, or within 1 week of landing back on Earth."

In 1991, Hughes-Fulford flew on STS-40, the first United States space shuttle mission dedicated to medical research. During that mission, she participated in experiments that identified T-cells as the particular components of immune function that were compromised. Her current study is the first to identify a specific mechanism for T-cell suppression in a weightless environment.

"It’s a potential key to understanding the lack of immune response in microgravity, thereby giving us a unique target for treatment," Hughes-Fulford says. She notes that the problem of immune function must be solved if human beings are ever to live and work in space for extended periods of time.

Hughes-Fulford will continue her research in September, 2006, when Russian cosmonauts carry a custom-designed container housing the same experiment aboard a Soyuz spacecraft that is scheduled to deliver supplies and experiments to the International Space Station and then return to Earth. "We know how these genes behave in simulated microgravity," she says. "The results from Soyuz should tell us what happens during spaceflight, in real microgravity."

Other authors of the study include J.B. Boonyaratanakornkit, BS, of UCSF; Augusto Cogoli, PhD, of the Swiss Federal Institute of Technology; Chai-Fei Li, BS, of the Northern California Institute for Research and Education; Thomas Schopper, BS, of the Swiss Federal Institute of Technology; and Proto Pippia, PhD, and Graci Galleri, PhD, of the University of Sassari, Italy.

Steve Tokar | EurekAlert!
Further information:
http://www.ucsf.edu/

More articles from Life Sciences:

nachricht Separate brain systems cooperate during learning, study finds
22.02.2018 | Brown University

nachricht Maelstroms in the heart
22.02.2018 | Max-Planck-Institut für Dynamik und Selbstorganisation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Decoding the structure of the huntingtin protein

22.02.2018 | Life Sciences

Camera technology in vehicles: Low-latency image data compression

22.02.2018 | Information Technology

Minimising risks of transplants

22.02.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>