Study identifies key player in the body's immune response to chro...( HOUSTON (Sept. 3 2007) Osteopontin (...),Health

HOUSTON (Sept. 3, 2007) Osteopontin (OPN), a protein molecule involved in many different cellular processes, plays a significant role in immune deficiency and organ atrophy following chronic physiological stress, resulting in increased susceptibility to illness. These findings appear in the September 4th issue of the Proceedings of the National Academy of Sciences.

The study is supported by the National Space Biomedical Research Institute (NSBRI), the Busch Biomedical Research Grant, National Multiple Sclerosis Society, and Rutgers Technology Commercialization Fund. Authors on the paper include Dr. Yufang Shi, investigator on NSBRIs Radiation Effects Team and professor of molecular genetics, microbiology and immunology at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Dr. David T. Denhardt, one of the discoverers of OPN, professor of cell biology and neuroscience at Rutgers, the State University of New Jersey, and Kathryn X. Wang, graduate student in the Rutgers Graduate Program in Cell and Developmental Biology.

Following periods of prolonged physical stress such as when astronauts live in microgravity, white blood cells that fight disease, called lymphocytes, die at an increased rate and immune system organs like the thymus and spleen lose mass and begin to atrophy, said Dr. Shi.

Immune system organs include the thymus, spleen, lymph nodes and bone marrow.

By determining the role of lymphocyte death in a stressed immune system, we may be able to develop therapies to maintain a healthy immune system, which can help in space and in clinical settings to prevent and treat malignancy and infections, Shi said.

It is known that spaceflight and long periods of physiological stress cause changes in the immune system. Until now, the role of OPN in the stress response of immune organs has never been examined, Shi said.

Evidence suggests that astronauts may suffer i
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