Nav: Home

Stop eating! You are full

March 28, 2017

Researchers have identified a molecule sent by fat cells to the fly brain that senses when they have had enough food and inhibits feeding, according to a study publishing March 28 in the open access journal PLOS Biology by Walton Jones of the Korea Advanced Institute of Science and Technology in Daejeon, and colleagues.

Fat is the primary long-term energy storage molecule in animals, and the control of fat levels is critical for survival. In mammals, the hormone leptin induces eating in response to fat loss, but so far, no corresponding signal has been identified, either in mammals or any other animal, that inhibits eating in response to fat gain. Because fruit flies replicate many of the feeding-related regulatory mechanisms and genes known to operate in humans, they make a good model for the search for such an inhibitory signal.

To conduct their search, the authors focused on short non-coding RNAs or microRNAs, which are well-known inhibitors of gene expression. They first searched for microRNAs that, when overexpressed in fat tissue, affected feeding behavior, and second for the gene targets of those microRNAs. They identified a microRNA called miR-iab-4, which increased feeding by more than 27%, and a target gene called purple, which was expressed in fat bodies.

Reducing purple expression enhanced feeding, suggesting its normal function was to inhibit it. Purple is known to be one of two fat-body enzymes that build a molecule called PTP, which is released by fat bodies and circulates in the fly brain. There, a third enzyme converts PTP into a well-known enzyme cofactor, called tetrahydrobiopterin (BH4). BH4 is required in the neurons that produce NPF, a neuropeptide that regulates feeding. The authors showed that loss of purple in the fat body, or loss of BH4 in neurons, led to increased release of NPF and increased feeding. Conversely, increasing BH4 in neurons reduced NPF release and decreased feeding. Finally, they showed that feeding flies a low-calorie diet reduced expression of the fat body enzymes that control BH4 production, and led to increased feeding.

The results in this study suggest that BH4 plays a key role in suppressing appetite in flies, and that PTP released from fat bodies delivers a signal to the brain indicating that energy stores are sufficient and that feeding can stop. While these results apply only to flies currently, the identification of this appetite-suppression mechanism will surely spur research into related pathways in humans.

"Our study indicates fat tissue sends a molecular signal to the fly brain to regulate feeding behavior," said Jones. "Further studies will be needed to determine if a similar system acts in mammals, and if so, whether it can be safely manipulated to help achieve weight loss, or gain, in people."
-end-
In your coverage please use this URL to provide access to the freely available article in PLOS Biology: http://dx.doi.org/10.1371/journal.pbio.2000532

Citation: Kim D-H, Shin M, Jung S-H, Kim Y-J, Jones WD (2017) A fat-derived metabolite regulates a peptidergic feeding circuit in Drosophila. PLoS Biol 15(3): e2000532. doi:10.1371/journal.pbio.2000532

Funding: KAIST High-Risk High-Return Project http://www.kaist.edu (grant number N10150061). Received by WDJ. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. National Research Foundation of the Republic of Korea http://www.nrf.re.kr (grant number 2013R1A1A2011339). Received by WDJ. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. National Research Foundation of the Republic of Korea http://www.nrf.re.kr (grant number 2010-0006217). Received by WDJ. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

PLOS

Related Neurons Articles:

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.
Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.
How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.
A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.
Shaping the social networks of neurons
Identification of a protein complex that attracts or repels nerve cells during development.
With these neurons, extinguishing fear is its own reward
The same neurons responsible for encoding reward also form new memories to suppress fearful ones, according to new research by scientists at The Picower Institute for Learning and Memory at MIT.
How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
More Neurons News and Neurons Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.