In Lou Gehrig's Disease (ALS) and other neurodegenerative diseases, nerve cells usually die in stages, with axons deteriorating first and the cells themselves perishing later. Axon degeneration may represent a turning point for patients, after which so much nerve damage has accumulated that treatments won't work.
A JCB study shows how the protein CNTF activates the transcription factor STAT3 (green), which lingers in the axon (blue) and helps stabilize microtubules by inhibiting a protein called stathmin (magenta). STAT3 and stathmin colocalize in axonal branch points (arrowheads) and growth cones (arrow).
Credit: Selvaraj, B.T., et al. 2012. J. Cell Biol. doi:10.1083/jcb.201203109
Researchers have tested several proteins for their ability to save axons. One of these molecules, CNTF, rescues axons in rodents and extends their lives. But it caused severe side effects in patients during clinical trials. "Acting on the same pathway but farther downstream could be an ideal way to improve the situation for motor neuron disease" and possibly for other neurodegenerative diseases, says senior author Michael Sendtner from the University of Wuerzburg in Germany.
To discover how CNTF works, Sendtner and his colleagues studied mice with a mutation that mimics ALS. The researchers found that CNTF not only prevented shrinkage of the rodents' motor neurons, it also reduced the number of swellings along the axon that are markers of degeneration. It is known that CNTF indirectly turns on the transcription factor STAT3, so the researchers wanted to determine if STAT3 is behind CNTF's protective powers. They tested whether CNTF helps motor neurons that lack STAT3 and discovered that, in the mutant mice, axons lacking STAT3 were half as long as those from a control group after CNTF treatment
Once it has been activated, STAT3 typically travels to the nucleus of the neuron to switch on genes. But the researchers were surprised to find that most of the axonal STAT3 did not move to the nucleus and instead had a local effect in the axon. Specifically, the team found that activated STAT3 inhibited stathmin, a protein that normally destabilizes microtubules. When the team removed stathmin in motor neurons from the mutant mice, the axons grew at the same rate as axons from normal mice but didn't elongate any faster after doses of CNTF. These results indicate that CNTF mainly stimulates axon growth by thwarting stathmin and suggests that drugs to block stathmin could slow neuron breakdown in patients with neurodegenerative diseases.
About The Journal of Cell Biology (JCB)
JCB is published by The Rockefeller University Press. All editorial decisions on manuscripts submitted are made by active scientists in conjunction with our in-house scientific editors. JCB content is posted to PubMed Central, where it is available to the public for free six months after publication. Authors retain copyright of their published works, and third parties may reuse the content for non-commercial purposes under a creative commons license. For more information, please visit www.jcb.org.
Selvaraj, B.T., et al. 2012. J. Cell Biol. doi:10.1083/jcb.201203109
Bolstering fat cells offers potential new leukemia treatment
17.10.2017 | McMaster University
Ocean atmosphere rife with microbes
17.10.2017 | King Abdullah University of Science & Technology (KAUST)
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Life Sciences
17.10.2017 | Earth Sciences