Researchers are conducting two separate studies that could lead to the development of new treatments for autoimmune diseases.

Dr. Chen, professor of molecular biology and a Howard Hughes Medical Institute (HHMI) investigator at UTSW, is senior author of both studies available online and published in today's print edition of Science. Although the immune-boosting response of DNA has long been recognized, the mechanism underlying that response remained a mystery, he said.
"In his 1908 Nobel acceptance speech, Ilya Mechnikov noted that surgeons in Europe treated patients with nucleic acids – the building blocks of DNA – to boost their patients' immune responses. That observation came four decades before scientists showed that DNA was the carrier of genetic information," Dr. Chen said.
Dr. Chen credits a uniquely biochemical approach for solving the longstanding puzzle. The approach used classical protein purification combined with a modern technology called quantitative mass spectrometry to identify the mysterious compound at the heart of the discovered process.
Under normal conditions, DNA is contained within membrane-bound structures such as the nucleus and mitochondria that are suspended within the cell's soupy interior, called the cytoplasm, he said. DNA in the cytoplasm is a danger signal that triggers immune responses, including production of type-1 interferons (IFN).
"Foreign DNA in the cytoplasm is a sign of attack by a virus, bacteria, or parasite," Dr. Chen said. "Host DNA that somehow leaks into the cytoplasm can trigger autoimmune conditions, like lupus, Sjogren's syndrome, and Aicardi-Goutiere's syndrome in humans."
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The cGAMP functions as a second messenger that binds to an adaptor protein called STING, which activates a cell signaling cascade that in turn produces agents of inflammation: interferons and cytokines.
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Source-Eurekalert