A recent study conducted at UC Riverside has discovered that female mice are more resistant to obesity compared to their male counterparts, thanks to the presence of the immune protein RELMalpha. The study, which used a mouse model of high-fat diet-induced obesity, found that when the protein was deleted, female mice became susceptible to obesity, similar to male mice.
These findings have significant implications for potential new treatments for obesity, as well as highlighting the importance of considering sex differences in addressing metabolic diseases. Currently, obesity is a growing public health concern in the United States, with over 30% of American adults classified as obese. This condition is also a risk factor for various diseases, including diabetes, cardiovascular disease, and even COVID-19.
RELMalpha is part of a family of proteins that are highly expressed in infectious and inflammatory diseases. The study discovered that RELMalpha regulates two types of immune cells: anti-inflammatory macrophages and eosinophils. Female mice expressed higher levels of RELMalpha and had higher levels of eosinophils, which protected them against obesity and inflammation.
However, when RELMalpha was deleted in female mice, they lost their protection against obesity and inflammation. The study also found that treating female mice with eosinophils or RELMalpha reduced obesity. On the other hand, male mice expressed less RELMalpha and had fewer eosinophils, leading to inflammatory macrophages that promoted obesity.
Although the effects of RELMalpha deficiency were significant in males as well, they were not as pronounced as in females. This study underscores the importance of considering sex differences when addressing metabolic diseases such as obesity.
The researchers suggest that promoting the RELMalpha-eosinophil-macrophage axis could offer novel therapies for combating obesity. The study was supported by grants from the National Institutes of Health and was published in the journal eLife.
These findings provide valuable insights into the complex mechanisms of obesity and offer hope for potential future treatments. By understanding the role of RELMalpha and its interaction with immune cells, researchers can further explore targeted interventions to combat this growing public health concern.