New protein discovery could improve treatments for diseases

Scientists have made a significant discovery that could lead to new treatments for autoimmune diseases, including COVID-19 and Alzheimer’s. They identified a previously unknown protein called ArfGAP2, which is essential for triggering immune responses. This breakthrough came from studying a rare condition known as STING-associated vasculopathy (SAVI). This disease affects one in a million births and causes the immune system to attack healthy tissues, mainly in the lungs and limbs. SAVI is caused by an overactive protein called STING that keeps the immune system permanently activated, leading to serious tissue damage. To understand how this works, researchers at Washington University and the University of Pennsylvania focused on the role of ArfGAP2 in immune cells. They found that ArfGAP2 helps release proteins called cytokines, which are vital for immune responses. Without ArfGAP2, the release of these immune proteins could not occur, meaning the immune response could be uncontrolled. Scientists compared this to a train station, where ArfGAP2 acts as a conductor that directs the release of important molecules. If ArfGAP2 and STING don’t work together, the immune response is halted. To explore potential treatments, researchers tested genetically modified mice lacking ArfGAP2. They found that these mice did not experience the harmful immune responses typical of SAVI, showing that blocking this protein could stop overactive immune reactions. The researchers believe that targeting ArfGAP2 could be effective for other diseases like COVID-19 and Alzheimer’s, where excessive immune responses cause damage. Autoimmune diseases currently affect more than 15 million people in the U.S. The study's findings have been published in the journal Cell.