I recently saw a program, that said that austic people have TOO MANY cells in the prefrontal cortest, thus they misfire and cause cells confusion.
Thanks,
Tamar
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It is not our differences that divide us.
It is our inability to recognize, accept, and celebrate those differences.
~ Audre Lorde
________________________________
From: Meir Weiss <[log in to unmask]>
To: [log in to unmask]
Sent: Monday, November 28, 2011 2:28 PM
Subject: FW: NEURONS GROWN FROM SKIN CELLS MAY HOLD CLUES TO AUTISM
-----Original Message-----
From: NIH news releases and news items [mailto:[log in to unmask]] On
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Sent: November 28, 2011 16:35
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Subject: NEURONS GROWN FROM SKIN CELLS MAY HOLD CLUES TO AUTISM
U.S. Department of Health and Human Services NATIONAL INSTITUTES OF HEALTH
NIH News National Institute of Mental Health (NIMH)
<http://www.nimh.nih.gov/> Embargoed for Release: Sunday, November 27, 2011,
1 p.m. EST
CONTACT: Jules Asher, NIMH press office,
301-443-4536,<e-mail:[log in to unmask]>
NEURONS GROWN FROM SKIN CELLS MAY HOLD CLUES TO AUTISM Rare syndrome's
workings could help explain how brain wiring goes awry -- NIH-funded study
Potential clues to how autism miswires the brain are emerging from a study
of a rare, purely genetic form of the disorders that affects fewer than 20
people worldwide. Using cutting-edge "disease-in
a-dish"(http://www.nimh.nih.gov/about/director/2011/skin-cells-to-neurons-di
sease-in-a-dish-promises-shortcut-to-discovery.shtml) technology,
researchers funded by the National Institutes of Health have grown patients'
skin cells into neurons to discover what goes wrong in the brain in Timothy
Syndrome (http://ghr.nlm.nih.gov/condition/timothy-syndrome). Affected
children often show symptoms of autism spectrum disorders
(http://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-pervasive-d
evelopmental-disorders/index.shtml) along with a constellation of physical
problems.
Abnormalities included changes in the composition of cells in the cortex,
the largest brain structure in humans, and of neurons that secrete two key
chemical messengers. Neurons that make long-distance connections between
the brain's hemispheres tended to be in short supply.
Most patients with Timothy Syndrome meet diagnostic criteria for an autism
spectrum disorder. Yet, unlike most cases of autism, Timothy syndrome is
known to be caused by a single genetic mutation.
"Studying the consequences of a single mutation, compared to multiple genes
with small effects, vastly simplifies the task of pinpointing causal
mechanisms," explained Ricardo Dolmetsch, Ph.D.
(http://www.nimh.nih.gov/media/video/dolmetsch.shtml), of Stanford
University, a National Institute of Mental Health (NIMH) grantee
(http://projectreporter.nih.gov/project_info_description.cfm?aid=8206064&icd
e=1032931) who led the study. His work was partially funded by a NIH
Director's Pioneer Award
(http://projectreporter.nih.gov/project_info_description.cfm?aid=8136230&icd
e=10319997).
Dolmetsch, and colleagues, report on their findings Nov. 27, 2011 in the
journal Nature Medicine.
"Unlike animal research, the cutting-edge technology employed in this study
makes it possible to pinpoint molecular defects in a patient's own brain
cells," said NIMH Director Thomas R. Insel, M.D. "It also offers a way to
screen more rapidly for medications that act on the disordered process."
Prior to the current study, researchers knew that Timothy syndrome is caused
by a tiny glitch in the gene that codes for a calcium channel protein in
cell membranes. The mutation results in too much calcium entering cells,
causing a tell-tale set of abnormalities throughout the body. Proper
functioning of the calcium channel is known to be particularly critical for
proper heart rhythm -- many patients die in childhood of arrhythmias -- but
its role in brain cells was less well understood.
To learn more, Dolmetsch and colleagues used a new technology called induced
pluripotent stem cells (iPSCs)
(http://stemcells.nih.gov/info/basics/basics10.asp). They first converted
skin cells from Timothy Syndrome patients into stem cells and then coaxed
these to differentiate into neurons.
"Remarkable reproducibility" observed across multiple iPSC lines and
individuals confirmed that the technique can reveal defects in neuronal
differentiation -- such as whether cells assume the correct identity as the
brain gets wired-up in early development, said the researchers. Compared to
those from controls, fewer neurons from Timothy Syndrome patients became
neurons of the lower layers of the cortex and more became upper layer
neurons. The lower layer cells that remained were more likely to be the
kind that project to areas below the cortex. In contrast, there were
fewer-than-normal neurons equipped to form a structure, called the corpus
callosum, which makes possible communications between the left and right
hemispheres.
Many of these defects were also seen in parallel studies of mice with the
same genetic mutation found in Timothy syndrome patients. This supports the
link between the mutation and the developmental abnormalities.
Several genes previously implicated in autism were among hundreds found to
be expressed abnormally in Timothy Syndrome neurons. Excess cellular calcium
levels also caused an overproduction of neurons that make key chemical
messengers. Timothy Syndrome neurons secreted 3.5 times more norepinephrine
and 2.3 times more dopamine than control neurons. Addition of a drug that
blocks the calcium channel reversed the abnormalities in cultured neurons,
reducing the proportion of catecholamine-secreting cells by 68 percent.
The findings in Timothy Syndrome patient iPSCs follow those in Rett
Syndrome, another single gene disorder that often includes autism-like
symptoms. About a year ago, Alysson Muotri, Ph.D., and colleagues at
University of California, San Diego, reported deficits
(http://www.eurekalert.org/pub_releases/2010-11/uoc--urc_1110410.php) in the
protrusions of neurons, called spines, that help form connections, or
synapses. The Dolmetsch team's discovery of earlier (neuronal fate) and
later (altered connectivity) defects suggest that disorders on the autism
spectrum affect multiple stages in early brain development.
"Most of these abnormalities are consistent with other emerging evidence
that ASDs arise from defects in connectivity between cortex areas and show
decreased size of the corpus callosum," said Dolmetsch. "Our study reveals
how these might be traceable to specific mechanisms set in motion by poor
regulation of cellular calcium. It also demonstrates that neurons derived
from iPSCs can be used to identify the cellular basis of a
neurodevelopmental disorder."
The mechanisms identified in this study may become potential targets for
developing new therapies for Timothy Syndrome and may also provide insights
into the neural basis of deficits in other forms of autism, said Dolmetsch.
The mission of the NIMH is to transform the understanding and treatment of
mental illnesses through basic and clinical research, paving the way for
prevention, recovery and cure. For more information, visit the NIMH website
<http://www.nimh.nih.gov/index.shtml>.
About the National Institutes of Health (NIH): NIH, the nation's medical
research agency, includes 27 Institutes and Centers and is a component of
the U.S. Department of Health and Human Services. NIH is the primary federal
agency conducting and supporting basic, clinical, and translational medical
research, and is investigating the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and its programs,
visit <www.nih.gov>.
--------------------------------------
REFERENCE:
Using iPS cell-derived neurons to uncover cellular phenotypes associated
with Timothy Syndrome. Pasca SP, Portmann T, Voineagu I, Yazawa M,
Shcheglovitov O, Pasca AM, Cord B, Palmer TD, Chikahisa S, Seiji N,
Bernstein JA, Hallmayer J, Geschwind DH, Dolmetsch RE. November 27, 2011.
Nature Medicine.
--------------------------------------
The html version of this release contains images of:
--a catecholamine-producing neurons at
<http://www.nimh.nih.gov/images/news-items/dolmetsch-timothy-iPSC-catechol.j
pg>
-- a corpus collosum at:
<http://www.nimh.nih.gov/images/news-items/dolmetsch-timothy-iPS-collosum.jp
g>
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