UMDNJ-Robert Wood Johnson Medical Sschool Professor
Co-authors Article Identifying Likely Cause of
Immune Deficiency After Chronic Stress
NEW BRUNSWICK—Osteopontin (OPN), a protein molecule involved in a variety of cellular processes, contributes significantly to immune deficiency and lymphoid organ atrophy following prolonged physiological stress, according to studies conducted jointly by University of Medicine and Dentistry of New Jersey and Rutgers University researchers.
Dr. Yufang Shi, Professor of Molecular Genetics, Microbiology and Immunology at UMDNJ - Robert Wood Johnson Medical School and investigator on the National Space Biomedical Research Institute’s Radiation Effects Team, co-authored the paper with Dr. David T. Denhardt, one of the discoverers of OPN and 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.
Their research findings are discussed in an article, which appeared in the September 11 print issue of the Proceedings of the National Academy of Sciences of the United States of America.
The article also was published in the September 4 online edition of the Proceedings of the National Academy of Sciences of the United States of America. To view the article click on the following link:
According to Shi, "OPN plays a key role in stress-induced loss of infection-fighting white blood cells, called lymphocytes, after extended periods of physical stress."
Immune system organs include the thymus, the spleen, lymph nodes and bone marrow.
Shi and his colleagues are interested in understanding why people under stressful situations, such as astronauts during spaceflight, experience increased rates of infections. Their breakthrough research revealed an important function of OPN in this process.
"This new finding is expected to lead to the development of therapies to prevent damage to the immune system for people under stress, including astronauts in space," Shi said.
It also may help, clinically, in the prevention and treatment of malignancy and infections.
Through an animal study, Shi and colleagues simulated spaceflight conditions to investigate its effects on the immune system. They found that infection-fighting white blood cells inappropriately die off in large numbers, through a process called apoptosis, leading to immune-organ atrophy and the decreased ability of the immune system to protect the body from illness.
Researchers discovered that the group with the normal OPN gene experienced weight loss, spleen and thymus atrophy, and a reduced number of white blood cells. In addition, increased levels of corticosterone, a steroid that contributes to the death of white blood cells, were found only in the group with normal OPN.
By contrast, the group lacking the OPN gene showed statistically insignificant changes in weight and the levels of corticosterone and were more similar to the control group.
The team determined that under chronic physical stress, OPN must be present for the increase in corticosterone, which leads to atrophy and white blood cell death.
"Since stress is a major factor affecting human health in modern society, this finding will lead to a better understanding and preventative measures and clinical treatments for various diseases in the future," Shi said.
Their research continues to be supported by the National Space Biomedical Research Institute (NSBRI). NSBRI is a NASA-funded consortium of institutions studying the health risks related to long-duration spaceflight. The Institute’s science, technology and education projects take place at more than 70 institutions across the United States.
To interview Dr. Yufang Shi, contact Zenaida Mendez at (973) 972-3000.
UMDNJ is the nation's largest free-standing public health sciences university with more than 5,700 students attending the state's three medical schools, its only dental school, a graduate school of biomedical sciences, a school of health related professions, a school of nursing and a school of public health on five campuses. Annually, there are more than two million patient visits at UMDNJ facilities and faculty practices at campuses in Newark, New Brunswick/Piscataway, Scotch Plains, Camden and Stratford. UMDNJ operates University Hospital, a Level I Trauma Center in Newark, and University Behavioral HealthCare, a statewide mental health and addiction services network.