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
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.