Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny RNA molecule may have role in polycystic ovary syndrome, insulin resistance

20.03.2013
A group of tiny RNA molecules with a big role in regulating gene expression also appear to have a role in causing insulin resistance in woman with polycystic ovary syndrome and, perhaps, in all women, researchers report.

Research in the journal Diabetes, indicates that high activity levels of a microRNA called miR-93 in fat cells impedes insulin's use of glucose, contributing to PCOS as well as insulin resistance, said Dr. Ricardo Azziz, reproductive endocrinologist and PCOS expert at the Medical College of Georgia at Georgia Regents University.

"This is one of the first reports of a defect that may occur both in women who are insulin resistant and, in particular, in women with PCOS," said Azziz, the study's corresponding author. "Identifying this molecular mechanism helps us understand these common conditions better and points us toward targeted therapies to correct these problems in women."

PCOS affects about 10 percent of women and is characterized by excess male hormone, irregular ovulation and menstruation and is associated with an increased risk for insulin resistance, which can lead to diabetes and heart disease.

Researchers looked at fat cells from the lower abdomen of 21 women with PCOS and 20 controls. In all the women with PCOS, they found over expression of miR-93 and decreased expression of GLUT4, a key protein that regulates fat's use of glucose for energy. Fat, a large organ in even a thin individual, is where a lot of glucose usage via insulin occurs.

GLUT4 expression was lowest in the women with PCOS who also were insulin resistant. They also found the expression was low in members of the control group who were insulin resistant.

"Low levels of GLUT4 in fat appear to be affecting insulin resistance in general and to have a more dramatic impact in PCOS," Azziz said. MiR-93 was known to impact GLUT4 in other cell types and to have a role in reproduction, infertility and lipid metabolism. "There has been no clear mechanism to describe insulin resistance in PCOS and we believe this is one of the pathways," said Dr. Yen-Hao Chen, cell biologist at MCG and the study's first author.

Interestingly, the investigators found that two other microRNAS - miR-133 and miR-223, which are known to regulate GLUT4 expression in heart muscle cells - also were over expressed but only in the fat cells of PCOS patients, Chen said. This exclusivity implicates the tiny molecules in the underlying condition of PCOS, Chen said. The researchers don't know yet if the two are related to miR-93. "We are just beginning to understand the role of these small molecules in PCOS and insulin resistance and much work remains to be done," Azziz said.

Follow up studies include better understanding just how microRNAs impact GLUT4, identifying other microRNAS that do – including looking further at miR-133 and 223 – and identifying what factors impact the tiny RNA molecules.

Humans use both insulin and non-insulin related mechanisms to use blood sugar, or glucose, as an energy source.

Azziz and his colleagues recently showed in Journal of Clinical Endocrinology & Metabolism that women with PCOS have defects in both mechanisms. In fact, PCOS women who had the most difficulty controlling glucose via insulin were also the ones with the greatest declines in their ability to use non-insulin approaches. More typically, when insulin resistance increases, the body's non-insulin dependent usage increases, apparently to help compensate.

The studies were funded by the National Institutes of Health and Helping Hand of Los Angeles Inc. Study participants were from the Los Angeles area. Co-authors include scientists from the Catholic University of Korea and the University of California, Los Angeles.

Toni Baker | EurekAlert!
Further information:
http://www.gru.edu

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>