Role of SF1 neurons in adipose tissue inflammation

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Just as there are different types of fat in food, there are different types of adipose tissue in your body. White adipose tissue (WAT) is the most abundant form of fat, whereas brown adipose tissue (BAT) plays an important role in thermogenesis, the process by which heat is generated by burning calories. Recent studies have shown that the difference in association between WAT depot volume and cardiovascular disease may result from differences in the characteristics of subcutaneous and abdominal WAT. Subcutaneous WAT is less inflammatory than abdominal WAT. Inflammation in areas containing WAT may influence how obesity affects overall metabolic and cardiovascular health. However, it is unclear whether the nervous system controls inflammation differently in different regions of fat. Japanese researchers have shed new light on a type of neuron in the brain that plays a key role in this type of inflammation within fat.

In a new study published in Cell Reports, researchers led by the National Institute for Physiological Sciences (NIPS) used a mouse model fed a high-fat diet to study neurons that express a protein called steroidogenic factor 1 (SF1). demonstrated how it affects inflammation in different areas. Or a “depot” of fat.

SF1-expressing neurons were previously shown to reside in the hypothalamus, a region of the brain that controls hunger and peripheral metabolism. A NIPS-led research team will investigate the effects of SF1 neurons on various fat depots, including WAT, found in the inguinal (subcutaneous) and epididymal (abdominal) regions of mice fed a high-fat diet. started.

“We first investigated the effects of inactivating SF1-expressing neurons in the hypothalamus,” says Yasuhiko Minokoshi, the lead author of the study. “We found that mice without SF1-expressing neurons gained significantly more weight on both normal and high-fat diets. Although epididymal WAT weight was indeed reduced, no significant changes were seen in BAT, suggesting that SF1 neurons regulate fat metabolism differently in different regions of the mouse body. I have shown that there seems to be

The researchers found that inflammatory and immune cell marker expression and immune cell infiltration were elevated in inguinal WAT of mice lacking SF1-expressing neurons and fed a high-fat diet, whereas epididymal WAT found that those markers showed high values. Values ​​for both mice lacking and not lacking SF1-expressing neurons. In BAT, markers of thermogenesis were greatly reduced in mice lacking SF1-expressing neurons. Conversely, activation of SF1 neurons in mice fed a high-fat diet resulted in reduced levels of inflammatory gene expression in inguinal, but not epididymal WAT, and increased thermogenic function in BAT. brought

“Our results show that SF1 neurons in the hypothalamus help suppress the inflammatory response induced in the inguinal WAT by a high-fat diet,” said one of the co-corresponding authors. Mr. Kunio Kondo says:

“These neurons also activate thermogenic activity of BAT, but do not appear to affect the inflammatory response or thermogenesis of epididymal WAT,” said lead author Misbah Rashid.

The researchers further found that SF1 neurons exert their effects through sympathetic nerve connections to the inguinal WAT. Some specific SF1 neurons appear to modulate inflammatory responses and thermogenesis differently in individual depots of fat, via tissue innervating sympathetic nerves. The research team’s work has provided a better understanding of SF1 neurons and how they regulate inflammation, one of the drivers of obesity-related diseases.

reference: Rashid M, Kondo K, Parfarbi G, Nakashima K Ichiro, Minokoshi Y. Inhibition of high-fat diet-induced inflammatory response in adipose tissue by SF1-expressing neurons in the ventromedial hypothalamus. cell report. 2023;42(6):112627. Doi: 10.1016/j.cellrep.2023.112627

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