Protein found to protect females against obesity

Currently, more than 30% of American adults are classified as obese. A risk factor for several diseases, including diabetes, cardiovascular disease, and COVID-19, obesity is an important and growing public health concern.

RELM, or resistin-like molecules, constitute a family of proteins secreted by mammals that are highly expressed in infectious and inflammatory diseases. One of these proteins, RELMalpha, is quickly triggered in the mouse body following infection and serves to protect the body's tissues. It has a sequence and functions similar to resistin in humans.

Using a mouse model of high-fat diet-induced obesity, a team of scientists at the University of California, Riverside, has found that, compared to males, female mice are protected against obesity and inflammation because they secrete more of an immune protein called RELMalpha. The study is published in eLife.

When the researchers deleted RELMalpha in female mice, they found the mice were no longer protected from obesity, had fewer eosinophils, and had inflammatory macrophages — similar to male mice. The research team found RELMalpha deficiency had significant effects in males also but to a lesser extent than in females.

According to Nair, the study is novel in showing a previously unrecognized role for RELMalpha in modulating metabolic and inflammatory responses during diet-induced obesity that is sex-dependent.

“Our results highlight a critical ‘RELMalpha–eosinophil–macrophage axis’ that functions in females to protect from diet-induced obesity and inflammation,” she said. “Promoting these pathways could, therefore, provide novel therapies for combating obesity.”

Reference: Protein found to protect females against obesity; eLife, DOI: 10.7554/eLife.86001