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Joseph Larkin in the lab

UF scientists show peptide quiets lupus symptoms in mice

  • Lupus is an autoimmune disease caused by immune cells that attack the body’s own tissues and cause chronic inflammation.
  • UF researchers have tested a new treatment in mice that suppresses signals that tell immune cells to jump into action.
  • While this kind of treatment for humans is still many years away, the researchers say their study can help open new avenues for the treatment of lupus and many other diseases that involve chronic inflammation.

Researchers with the University of Florida have used a peptide — a piece of a protein — to reduce symptoms associated with the autoimmune disease lupus.

This new approach to treating lupus was tested in mice, but the researchers say the findings could one day help human patients.

“Using this peptide, we treated mice that have the characteristics of human lupus, such as extra antibodies, renal disease, skin issues,” said Joseph Larkin III, senior author of the study and an associate professor in the UF/IFAS department of microbiology and cell science. “We saw that this peptide turned down T-cell activity — T-cells are a type of immune cell that drives lupus. We also saw a reduction in antibodies and positive effects in the kidneys and skin.”

The peptide, called the SOCS1 peptide, mimics the SOCS1 protein, which is naturally found in most animals, including humans.

The SOCS1 protein is involved in regulating the body’s immune response. That’s key for people with lupus, whose immune systems run on overdrive.

Normally, the immune system kicks in when it notices something like a virus that can cause you harm, Larkin said. As your body fights the virus, it produces antibodies and inflammation. Once your body gets rid of the invader, inflammation recedes, and you feel better.

“Lupus happens when the immune system turns on the body. Your immune system sees your own nucleic acids — the stuff that’s in DNA — as a threat,” Larkin said. “You are producing antibodies against yourself and inflammation becomes chronic. Chronic inflammation can lead to secondary health issues with the renal system, skin and other tissues.”

This cascade of events starts with the way cells communicate with each other.

“Cells communicate through cytokines, a kind of a protein. Cytokines tell a cell to make something or do something. Some cytokines are pro-inflammatory, and lupus patients have too many of them or a greater response to them,” Larkin said.

Imagine this pro-inflammatory message is like water coming out of a tap, Larkin explained. In people with lupus, the metaphorical bathtub is overflowing.

“SOCS1 intervenes in the communication process. It turns off the tap,” Larkin said.

The SOCS1 peptide mimics the way the SOCS1 protein functions in the body. The peptide was developed by Howard Johnson, one of the study’s co-authors and a professor emeritus in the department of microbiology and cell science.

“When we gave the mice in our study more SOCS1 in the form of the peptide, we saw improvements in their lupus-like symptoms compared to mice who did not receive the treatment,” Larkin said.

While a new treatment for lupus in people is still a long way off, Larkin says that the present research can offer insights into the treatment of other diseases as well.

“Inflammation is involved in many different diseases — rheumatoid arthritis, Chrohn’s Disease, some cancers, even Type II diabetes. Anything that we can gain in understanding how to regulate and control inflammation is really important to many of the diseases that affect us today,” Larkin said.

The study is published in the journal “Nature Scientific Reports.”

The study’s lead authors are current and former students in the UF/IFAS College of Agricultural and Life Sciences: Jatin Sharma, a doctoral student in microbiology and cell science, and Teresa Collins, who earned her doctorate in microbiology and cell science in 2017. The study’s second author, Tracoyia Roach, is also a doctoral student microbiology and cell science.