April 18 (UPI) -- A compound from immune cells treats psoriasis in mice, and might also be effective against other autoimmune diseases, including multiple sclerosis, rheumatoid arthritis and lupus, according to a study.
Researchers at the Washington University School of Medicine in St. Louis examined how the compound prevents an inflammatory pathway that is overactive in many autoimmune diseases. Their findings were published Wednesday in the journal Nature.
"We are taking advantage of the body's own anti-inflammatory power and showing that it can help in real situations when your own immune system is hurting you," senior author Dr. Maxim Artyomov, an assistant professor of pathology and immunology at Washington University, said in a press release.
When the body's defense system reacts against an infection, cells and molecules respond to an injury, causing inflammation -- such as the redness and swelling around an infected cut. Sometimes, however, inflammation moves toward the body's own healthy tissues and causes autoimmune diseases.
Anti-inflammatory drugs can be effective against many of these diseases, but not all of them.
From previous research, the researchers knew that inflammatory cells produce a compound called itaconate when they detect the presence of bacteria. They also know that, contrary to what should be expected, the compound can counteract inflammation.
"Everyone thought that if it is produced by inflammatory cells it should fight infection, but no -- it's anti-inflammatory," Artyomov said. "Now we know that itaconate compounds can help with autoimmune diseases, specifically in psoriasis and potentially in multiple sclerosis."
For the new study, the researchers treated inflammatory cells from mice and people with a modified form of itaconate called dimethyl itaconate.
The compound reduces levels of a key protein -- known as IkappaBzeta -- in the IL-17 inflammatory pathway. This fights off bacterial infections, but it also is the body's primary way to initiate autoimmune disease.
In past genetic studies, people with psoriasis were linked to variations in the gene for IkappaBzeta. With this in mind, the researchers tested whether the itaconate compound can reduce protein levels in a way to treat psoriasis in mice.
Mice with induced psoriasis-like symptoms in the ears received dimethyl itaconate or a placebo every day for a week.
The ears of mice that had received the placebo were red and swollen, but the ears of others treated with dimethyl itaconate had no signs of psoriasis.
The researchers are now studying whether itaconate compounds can reduce multiple sclerosis in mice after noticing structural similarities between dimethyl itaconate and dimethyl fumarate, which is the active ingredient in a multiple sclerosis drug.
"This small molecule is turning out to be really powerful," Artyomov said.