Protein Clumps Spread Inflammation ASC specks—protein aggregations that drive inflammation—are released from dying immune cells, expanding the reach of a defense response.
Research teams based in Germany and Spain have independently discovered that cells transmit inflammation by releasing ASC specks, bacteria-sized clumps of protein key for cytokines’ maturation, according to two papers appearing today (June 22) in Nature Immunology. The protein aggregations are a component of inflammasomes, which sense pathogens and cell damage and set off innate immune inflammation. Researchers previously thought inflammasomes acted only inside single cells, but this latest work has found that the ASC specks can effect extracellular inflammation. The teams also found that macrophages can take up released ASC specks, perpetuating the immune response.
ASC specks are prevalent in the tissues of people with some inflammatory diseases, and could be drug targets for reducing inflammation or diagnostic markers of these diseases, the researchers noted.
Their findings help explain the mystery of how relatively localized contact between a cell and a pathogen or product of cell damage can lead to widespread inflammation, explained George Dubyak, a cell physiologist at Case Western Reserve University in Cleveland, Ohio, who was not involved in the study. “The inflammasome specks can become carriers for intracellular signaling,” he said.
“I think this is much-needed information on how inflammation may actually spread after inflammasome activation and offers a whole host of activities for intervention now that have been unexplored,” saidRobert Keane, a professor of physiology and biophysics at the University of Miami Miller School of Medicine who was not involved in the study.