AgCenter Scientists Advance Theory On Fat Cells

JOHNNY MORGAN

 BATON ROUGE, LOUISIANA

 LSU AgCenter animal scientists studying adipose tissue in cattle say their findings could have human health implications.

AgCenter animal scientist Xing Fu currently manages two research programs. The first one is a biomedical research program using mice as a model to conduct health-related research, and the second is an agricultural research program primarily focusing on the improvement of beef cattle meat quality.

Fu and his graduate student, Qianglin Liu, are working on a project that promises to reduce the amount of visceral fat an animal produces.

Fu said visceral fat is not what we want. It creates waste in meat and fat in people.

The two are exploring ways to control fat development in all stages of growth in animals and humans.

Several factors control how a body manufactures these fats and other components. One controller of visceral fat is a protein called Tcf21.

The two are working with laboratory mice in search of a way to manipulate the body’s production of visceral fat. So far, they have found a potential way to control this process by manipulating Tcf21 expression.

White adipose tissue is distributed throughout the bodies of animals and humans, and it can be categorized into three types based on its anatomical location, also known as depots: visceral fat, subcutaneous fat and intramuscular fat. 

“In beef cattle, the amount of intramuscular fat is positively correlated with meat quality,” Liu said. “Conversely, excessive accumulation of subcutaneous and visceral fat in cattle reduces feed efficiency.” 

In humans, there is a stronger correlation between visceral fat accumulation and metabolic disorders such as diabetes than when compared to subcutaneous fat, Fu said. 

Therefore, it is crucial to develop strategies that can manipulate fat accumulation in a depot-specific manner.

“In our recent study, we discovered a gene called Tcf21, which is specifically expressed in adipogenic progenitor cells of visceral fat,” he said. “We found that Tcf21 plays an inhibitory role in the differentiation of adipogenic progenitor cells into fat cells.”

“By knocking out this gene from visceral adipogenic progenitor cells in neonatal mice,” he added, “we observed enhanced development of visceral fat, characterized by a greater number of visceral fat cells.”

Importantly, compared to wild mice, Tcf21 knockout mice showed protection against metabolic disorders when exposed to a Western, high-fat diet. 

After the high-fat diet challenge, visceral fat cells in the knockout mice remained relatively small, likely due to the larger population of fat cells. 

“The smaller size of fat cells made them less susceptible to hypoxia-induced cell death, resulting in reduced inflammation and insulin resistance,” Liu said. “So, in summary, our findings indicate that targeting Tcf21 can enhance the healthy expansion of visceral fat.”

Liu recently identified a similar expression pattern of Tcf21 in cattle adipose tissue. 

“We are currently investigating the possibility of manipulating fat accumulation specifically in different depots of beef cattle by targeting Tcf21 and other regulatory genes that exhibit depot-specific expressions,” he said. ∆

JOHNNY MORGAN: LSU AgCenter