New study discovers how Gram-negative bacterial infections cause random symptoms

UC Berkley researchers recently discovered how lipopolysaccharide, a disease-causing component of a Gram-negative bacteria's outer wall, induces various symptoms, according to a study published in Nature Communications.

The researchers discovered that LPS invade the membrane surrounding sensory nerve endings, which causes an abnormality that TRPA1 proteins detect, leading to an influx of positively-charged ions and the firing of electric signals to sensory nerve endings, which is perceived as pain. The influx of calcium ions through TRPA1 proteins also causes the expansion of blood vessels and tissue inflammation, which can lead to a change in blood pressure.

The study was led by Victor M. Meseguer of UC Berkley, who wanted to understand how a bacterial infection caused his toothache. Gram-negative bacterial infections can cause a number of symptoms, including low blood pressure, body aches, inflammation and acute pain. The process by which the symptoms arise, however, was unknown until Meseguer's discovery.

TRPA1 proteins are known detectors of harmful molecules found in a number of substances, including mustard, wasabi and tobacco. The new study adds LPS to the list.

"The identification of TRPA1 as a molecular determinant of direct LPS effects on pain-sensing neurons offers new insights into the pathogenesis of pain and neurovascular responses during bacterial infections and opens novel avenues for their treatment," Karel Talavera, the senior author of the study, said.