Neurons that control obesity in fruit flies seem to have been identified

Researchers from the California Institute of Technology (Caltech) are believed to have identified two groups of neurons in the brains of fruit fly. Apparently, these neurons have the ability to sense and control the fly’s fat stores in much similar way as neurons in the mammalian brain.

Researchers claimed that the existence of this type of control over fat deposition and metabolic rates seems to make the flies a potentially useful model while studying human obesity.

Caltech postdoctoral scholar Bader Al-Anzi claimed that by manipulating neural activity in fruit fly brains via transgenic techniques, the researchers discovered that fly fat-store levels seemed to have been measured and controlled by specific neurons in the brain similar to mammals. Also, silencing these neurons may perhaps create obese flies, while over activating them could lead to production of lean flies.

Mammalian brains seemed to be provided information regarding the body’s fat stores by hormones such as leptin and insulin. In addition, their brains appear to respond to that information by inducing changes in food intake and metabolism in order to maintain a constant body weight.

The researchers discovered that similar behavioral and metabolic changes may perhaps have occurred in the fruit flies. However, changes which occurred depended on which of the two sets of recently identified neurons appear to have been silenced.

For instance, silencing one group of neurons might lead to an increase in food intake and a decrease in metabolism. In addition, there seems to be an increase in the synthesis of fatty acids which are known to be the building blocks of fat.

Furthermore, silencing the other group supposedly led to a similar decrease in metabolism and increase in fatty-acid synthesis and a defect in the flies’ ability to utilize their fat stores.

The findings further revealed that increasing activity in either of the groups of neurons, on the other hand, seemed to have resulted in depletion of fat stores. Apparently, this depletion occurred when the flies’ metabolism was increased as well as their synthesis of fatty acids was decreased.

Lead researcher and professor of biology at Caltech, Kai Zinn stated that, “The next step is to see exactly how neurons regulate fat storage, and how the two different groups of neurons identified in this study work. They clearly regulate fat storage using different mechanisms.”

“The goal was to establish a model system for obesity in humans. This could, at some point, eventually define new drug targets,” elucidates Zinn.

Al-Anzi further said that the search for a model system appears to be critical. With obesity getting higher, statistics revealed that nearly more than one-third of adults in Western society are overweight. However, efforts to discover its roots in human brains or human genes seem to have similarly increased.

Unfortunately, Al-Anzi claimed that, “These efforts have not been extremely successful. While mammalian models such as the mouse have provided progress in the field, they tend to be difficult and expensive research subjects.”

He further continued, “The obesity research field would benefit greatly if another model organism could be used, one that is accessible for easy, fast, and affordable biomedical research methods. We believe the fruit fly can be such an organism.”

“There is a surprising amount of overlap between the simple fruit fly and more complex mammals in many basic biological processes. This is why it’s an excellent model system for exploring such medically relevant issues as Alzheimer’s disease, alcoholism, and addiction. Our results thus far suggest that body-weight regulation will be no different,” adds Al-Anzi.

Researchers have now recognized that fruit flies are certainly similar to mammals in the way they control fat deposition via the brain. Thus, they could perhaps instigate to test antiobesity dietary or drug treatments on flies whose fat-regulating neurons have been silenced.

“Treatments that cause these flies to return to normal body weight could then be retested for their effectiveness in a mammalian obesity model,” states Al-Anzi.

The neurons which were involved in the regulation of fat storage could perhaps also lead to identify the genes which allow for the vital communications between the brain and the fat stores.

“This can be done by identifying the genes that are selectively expressed only in those neurons. This has been shown to be the case for genes that regulate behavioral phenomena like learning and circadian rhythms. And we hope that body-weight and appetite regulation will be no different,” continues Al-Anzi.

Researchers claimed that this research should assist them in determining whether the mechanisms behind appetite and body-weight regulation in fruit flies have been preserved over evolutionary time and throughout the animal kingdom.

This research was called as “Obesity-blocking neurons in Drosophila.” This paper is believed to be the result of research originally led by Caltech biologist Seymour Benzer, a pioneer in the study of genes and behavior. Zinn was known to have continued this research after Benzer’s death in late 2007.

The findings of the research have been published in the journal, Neuron.