Scientists uncover mechanism by which chronic stress causes brain disease

Chronic stress has long been linked with neurodegeneration. Scientists at USC now think they may know why.

The study, which has tremendous implications for understanding and treating Alzheimer's disease, was published in the June issue of The .

Corresponding author Kelvin J. A. Davies, the James E. Birren Chair at the USC Davis School of , and Professor of Molecular & Computational Biology in the USC Dornsife College, examined the brains of rats that had experienced psychological stresses and found high levels of the RCAN1 gene. Davies and his colleagues suggest that — physical or mental — causes overexpression of RCAN1, in turn leading to neurodegenerative disease.

Think of a gene as a pattern or mold that generates specific proteins. For example, if 200 RCAN1 proteins are built where only 100 were needed, scientists would describe this as "overexpression" of the RCAN1 gene.

In a healthy person, the RCAN1 gene helps cells cope with stress. Overproduction, however, can eventually damage neurons, preventing the brain's signals from traveling and causing disease.

Chronic overproduction of RCAN1 causes hyper-phosphorylation of tau proteins in the brain.

Tau proteins stabilize microtubules, which are like the scaffolding used to build the brain's neurons. Previous research has shown that when the tau binds too much phosphate — a process called hyperphosphorylation — it forms snarls that prevent the brain's signals from effectively traveling.

"One can imagine that it becomes sticky and makes tangled scaffolding," Davies said.

These neurofibrillary tangles eventually choke the life out of neurons, killing off brain function a tiny piece at a time in what is outwardly recognized as degenerative disease.

Currently, there are two competing theories about the leading cause of neurodegeneration in Alzheimer's disease: overproduction of the Amyloid Beta peptide and tau hyperphosphorylation. Research in the Davies lab suggests that overexpression of RCAN1 is connected to both, and appears to unite the Amyloid Beta and tau theories of neurodegeneration.

"Both are clearly important, and RCAN1 could be the link," Davies said.

RCAN1 has been shown to be chronically overexpressed from birth in the brains of patients with Down syndrome. These patients develop neurofibrillary tangles and typically start to experience the onset of Alzheimer's disease around age 40.

Davies' lab has also shown a connection between too little RCAN1 production and Huntington's disease. "Our results suggest that the cellular levels of RCAN1 proteins must be kept within a fairly narrow range in order to avoid serious dysfunction," Davies said.

"By publishing this hypothesis, we hope to stimulate more research on the subject," he said.


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Jun 29, 2011
"Our results suggest that the cellular levels of RCAN1 proteins must be kept within a fairly narrow range in order to avoid serious dysfunction,"

One more extremely serious problem for evolutionary ideas.

Jun 29, 2011
"Our results suggest that the cellular levels of RCAN1 proteins must be kept within a fairly narrow range in order to avoid serious dysfunction,"

One more extremely serious problem for evolutionary ideas.

You're kidding right? So God keeps these proteins in check, most of the time, unless he doesn't, in which case we get disease? Where exactly is the "extremely serious problem for evolution" here? Are you saying that evolution cannot possibly explain this amazing balance of brain proteins? LOL

Jun 29, 2011
"Our results suggest that the cellular levels of RCAN1 proteins must be kept within a fairly narrow range in order to avoid serious dysfunction,"

One more extremely serious problem for evolutionary ideas.


Start explaining yourself, retard. The only things you ever contribute to this site are your drive-by, singular posts that get torn apart within hours and you never come back.

Troll.

Jul 05, 2011
And anything contrary to that "fine tuning" would be evidence of The Fall, right?

Besides the obvious things like aging you would obviously attribute to the fall (I'll give you some slack), what about fundamental design flaws?

Humans have a defective GULO gene, which prevents us from manufacturing our own vitamin c. Almost all living organisms can manufacture their own vitamin c, regardless of whether they age or how fast.

Why would humans have a detective GULO gene? It doesn't make sense that it's a consequence of the fall. We'd still be plenty vulnerable with it. Also a large chunk of the primate family has the same problem. Why would god have have done this to the primates, which are supposedly totally unrelated to humans, but not done this to other families of animals?

The answer is there was no fall and humans and GULO deficient primates evolved from a common ancestor with the same problem.

Jul 05, 2011
On the flip side, what about an organism that seemingly escaped the fall?

Everyone has heard about the immortal jellyfish. They must have been out of town during Genesis.

Jul 07, 2011
Kevin, Johan? Yoohoo

Jul 10, 2011
Keep em coming, scientists! A million thanks! My family needs ya!

Now. On to talking about cranks. ;P

Cowardly drive-by number 768 and counting.........

I was thinking, not one of these creationists have EVER thanked even one of us for our generous enlightenment. Maybe a "thanks for the post," once in a blue moon, but that's not the same, is it? Yeah, we usually ridicule them at the same time, but we didn't at first, and even still we don't always do it. WTF? That's evidence of some serious sociopathy right there. Right? I mean, they should be forgiving us for past ridicule, then thanking us for the knowledge, right? How /DO/ they deal with the whole love your enemy thing? I'm sure they see us as a form of enemy, so why no love and appreciation?

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