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Sonic hedgehoc, (No really!),wakes up stem cells

PostPosted: Sat Jun 07, 2008 7:12 am
by TwistedHelix
I'm not sure if this has been covered elsewhere, but I find this story remarkably encouraging: the whole concept of triggering our brains' own repair mechanisms overcomes so many of the hurdles facing other therapies that it sounds like a dream come true…
[ Back to EurekAlert! ] Public release date: 6-Jun-2008
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Contact: Patti Jacobs
Schepens Eye Research Institute
Brain stem cells can be awakened, say Schepens scientists
Study findings promise to help in treatment of brain diseases

Boston, MA-Scientists at Schepens Eye Research Institute have identified specific molecules in the brain that are responsible for awakening and putting to sleep brain stem cells, which, when activated, can transform into neurons (nerve cells) and repair damaged brain tissue. Their findings are published online this week in the Proceedings of the National Academy of Science (PNAS).

An earlier paper (published in the May issue of Stem Cells) by the same scientists laid the foundation for the PNAS study findings by demonstrating that neural stem cells exist in every part of the brain, but are mostly kept silent by chemical signals from support cells known as astrocytes.

³The findings from both papers should have a far-reaching impact,² says principal investigator, Dr. Dong Feng Chen, who is an associate scientist at Schepens Eye Research Institute and an assistant professor of ophthalmology at Harvard Medical School. Chen believes that tapping the brain¹s dormant, but intrinsic, ability to regenerate itself is the best hope for people suffering from brain-ravaging diseases such as Parkinson¹s or Alzheimer¹s disease or traumatic brain or spinal cord injuries.

Until these studies, which were conducted in the adult brains of mice, scientists assumed that only two parts of the brain contained neural stem cells and could turn them on to regenerate brain tissue-- the subgranular zone (SGZ) of the hippocampus and the subventricular zone (SVZ). The hippocampus is responsible for learning and memory, while the SVZ is a brain structure situated throughout the walls of lateral ventricles (part of the ventricular system in the brain) and is responsible for generating neurons reponsible for smell. So scientists believed that when neurons died in other areas of the brain, they were lost forever along with their functions.

In the first study, Chen¹s team learned that stem cells existed everywhere in the brain by testing tissue from different parts of adult mice brains in cultures containing support cells (known as astrocytes) from the hippocampus, where stem cells do regenerate.

In the cultures the stem cells from other brain regions came to life and turned into neurons.

When they compared the chemical makeup of the areas known to generate new neurons in the hippocampus with other parts of the brain, the team discovered that astrocytes in the hippocampus were sending one signal to the stem cells and that those from the rest of the brain were sending a different signal to stem cells.

In the second (PNAS) study, the team went on to discover the exact nature of those different chemical signals. They learned that in the areas where stem cells were sleeping, astrocytes were producing high levels of two related molecules--ephrin-A2 and ephrin-A3. They also found that removing these molecules (with a genetic tool) activated the sleeping stem cells.

The team also found that astrocytes in the hippocampus produce not only much lower levels of ephrin-A2 and ephrin-A3, but also release a protein named sonic hedghoc that, when added in culture or injected into the brain, stimulates neural stem cells to divide and become new neurons.

³These findings identify a key pathway that controls neural stem cell growth in the adult brain and suggest that it may be possible to reactivate the dormant regenerative potential by adding sonic hedgehoc, or blocking ephrin-A2 or ephrin-A3,² says Dr. Jianwei Jiao, the first author of the two papers.

The next step for the team will be to stimulate the sleeping stem cells in animals who are models of neurodegenerative disorders, such as Parkinson's disease, to see if the brains can repair themselves and restore their damaged functions.


Schepens Eye Research Institute is an affiliate of Harvard Medical School and the largest independent eye research institute in the country.

PostPosted: Sat Jun 07, 2008 7:55 am
by cheerleader
Thanks for sharing this, Dom.
I've become quite the science geek this year. I love the elegance.
We, in fact, contain all the answers we need. Or, the Kingdom of Heaven is truly within us!
Now, let's unlock it.



Re: Sonic hedgehoc, (No really!),wakes up stem cells

PostPosted: Sat Jun 07, 2008 9:18 am
by gwa
TwistedHelix wrote:I'm not sure if this has been covered elsewhere, but I find this story remarkably encouraging: the whole concept of triggering our brains' own repair mechanisms overcomes so many of the hurdles facing other therapies that it sounds like a dream come true…

I agree with your optimistic statement here, Dom. Great article!


PostPosted: Sat Jun 07, 2008 2:14 pm
by jimmylegs
if anyone's going looking further, "hedgehoc" is, i believe, a typo - it's really, truly, sonic hedgehog. as in the mammalian homologue. no jokes. unless the scientists are starting to go really insane with naming protocols and naming two different proteins sonic hedgehoc and sonic hedgehog?? omg, easy typo - i just had to fix one myself lol

PostPosted: Sat Jun 07, 2008 3:09 pm
by cheerleader
looks like it's different protein, JL!
2,120 google listings for sonic hegdgehoC 8O
Maybe they did run out of names????

PostPosted: Sat Jun 07, 2008 3:46 pm
by jimmylegs
yea it's weird before i had posted i did have a quick look, but many of those listings are typos related to the gaming character "sonic the hedgehog" which is repeatedly spelt "hedgehoc" on game sites... odd...

many of the other listings seem to be duplicates of the article above on various different news sites, perhaps quoting the same source.

a google search with the term protein filters out the game results.

hedgehog protein has over 300,000 results
hedgehoc protein has 169 results (including this thread hehe)

hedgehoc seems to appear on news sites, patent sites, and websites where english may be a second language - all highly typo-suspect. any road it seems to be a pretty common typo considering how often hedgehoc appears in use on the gaming sites, where there can only be one "sonic" ;)

PostPosted: Sat Jun 07, 2008 4:08 pm
by cheerleader
Yeah, my 13 year old son just informed me the game is hedgehoG!!!
We're laughing over this one....


PostPosted: Sat Jun 07, 2008 4:34 pm
by Lyon

PostPosted: Sat Jun 07, 2008 4:57 pm
by jimmylegs
lol! well i tried to find a little clip with this old jingle i can hear in my head but no luck :(