Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Our muscles measure the time of day

02.10.2017

Researchers funded by the SNSF have discovered a biological clock at work in our muscle cells. It could be a factor in regulating our metabolism and play a role in diabetes.

Biological clocks are ticking everywhere throughout our body. They trigger the release of the hormone melatonin during sleep, favour the secretion of digestive enzymes at lunchtime or keep us awake at the busiest moments of the day.


Source: SNF

A "master clock" in the brain synchronises all the subsidiary ones in various organs. For the first time, researchers funded by the Swiss National Science Foundation (SNSF) found that such a circadian clock is at work in our muscles. Perturbations of this machinery might be important for type 2 diabetes development. Their work has just been published in the magazine PNAS (*).

Sampling muscle tissue around the clock

Researchers from the University of Geneva, the University of Bath, the Université Claude Bernard in Lyon, EPFL, the University of Surrey, and the Nestlé Institute of Health Sciences discovered that levels of the various types of fat (lipids) contained in our muscle cells vary during the day, sometimes favouring one kind of lipid over another. Could a biological clock be at play?

The international team has tested the hypothesis with volunteer subjects. They synchronised every subject's master clock by asking them to adhere to a daily eating and sleeping routine one week prior to the experiment. Every four hours, researchers would take a very small sample of thigh muscle tissue and analyse its lipid composition.

The team observed a clear correlation between the muscle cell's lipid composition and the time of day, explains Howard Riezman, who co-directed the study in Geneva with colleague Charna Dibner. "As the combination of lipids varied substantially from one individual to another, we needed further evidence to corroborate these findings," he explains.

In a second step, the researchers switched to an in-vitro experiment. They cultivated human muscle cells and artificially synchronised them in the absence of a master clock, using a signal molecule normally secreted in the body. The researchers observed a periodic variation in the cell's lipid composition, similar to what they noticed in human subjects. But when they disrupted the clock mechanism by inhibiting the responsible genes, the periodically changing variations in the lipids were mostly lost.

Diabetes and sleep disorders are linked

"We have clearly shown that this variation of lipid types in our muscles is due to our circadian rhythm," explains first author Ursula Loizides-Mangold. "But the main question is still to be answered: what is this mechanism for?" Riezman thinks that the biological clock in the muscle, with its impact on the lipids, could help in regulating the cells' sensitivity to insulin. Indeed, lipids – being a component of the cell membrane – influence the molecules' ability to travel into and out of the muscle cells. Changes in its composition could tune the muscle's sensitivity to the hormone as well as its ability to take in blood sugar.

A low sensitivity of the muscle to insulin leads to a condition called insulin resistance, which is known to be a cause of type 2 diabetes. "Studies strongly suggest a link between circadian clocks, insulin resistance and diabetes development," explains Charna Dibner, the co-director of the study. "If we establish a link between circadian mechanisms and type 2 diabetes via lipid metabolism, this could have important therapeutic implications. Thanks to our new tools for studying human muscle cellular clocks in vitro, we now have the possibility to investigate this hypothesis in our next study."

(*) U. Loizides-Mangold et al.: Lipidomics reveals diurnal lipid oscillations in human skeletal muscle persisting in cellular myotubes cultured in vitro. PNAS (2017). DOI: 10.1073/pnas.1705821114

Contact

Dr. Charna Dibner
Department of Internal Medicine Specialties
Faculty of Medicine
University of Geneva
Phone: +41 (0)22 372 93 18
E-Mail: charna.dibner@hcuge.ch

Prof. Howard Riezman
Biochemistry Department
Faculty of Sciences
University of Geneva
Phone: +41 (0)22 379 64 69
E-Mail: howard.riezman@unige.ch

Dr. Ursula Loizides-Mangold
Department of Internal Medicine Specialties
Faculty of medicine
University of Geneva
Phone: +41 (0)22 379 5339
E-Mail: Ursula.Loizides-Mangold@unige.ch

Weitere Informationen:

http://www.snsf.ch/press-releases

Media Abteilung Kommunikation | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Rochester scientists discover gene controlling genetic recombination rates
23.04.2018 | University of Rochester

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>