www.checkbiotech.org ; www.raupp.info ; www.czu.cz

It sounds like science fiction: simply swallowing a pill, or eating a
specific food supplement, could permanently change your behaviour for the
better, or reverse diseases such as schizophrenia, Huntington's or cancer,
November 2005 by Alison Motluk.

Yet such treatments are looking increasingly plausible. In the latest
development, normal rats have been made to behave differently just by
injecting them with a specific amino acid. The change to their behaviour was
permanent. The amino acid altered the way the rat's genes were expressed,
raising the idea that drugs or dietary supplements might permanently halt
the genetic effects that predispose people to mental or physical illness.

It is not yet clear whether such interventions could work in humans. But
there is good reason to believe they could, as evidence mounts that a range
of simple nutrients might have such effects.

Two years ago, researchers led by Randy Jirtle of Duke University Medical
Center in Durham, North Carolina, showed that the activity of a mouse's
genes can be influenced by food supplements eaten by its mother just prior
to, or during, very early pregnancy (New Scientist, 9 August 2003, p 14).
Then last year, Moshe Szyf, Michael Meaney and colleagues at McGill
University in Montreal, Canada, showed that mothers could influence the way
a rat's genes are expressed after it has been born. If a rat is not licked,
groomed and nursed enough by its mother, chemical tags known as methyl
groups are added to the DNA of a particular gene.

The affected gene codes for the glucocorticoid receptor gene, expressed in
the hippocampus of the brain. The gene helps mediate the animal's response
to stress, and in poorly raised rats, the methylation damped down the gene's
activity. Such pups produced higher levels of stress hormones and were less
confident exploring new environments. The effect lasted for life (Nature
Neuroscience, vol 7, p 847).

Now the team has shown that a food supplement can have the same effect on
well-reared rats at 90 days old - well into adulthood. The researchers
injected L-methionine, a common amino acid and food supplement, into the
brains of well-reared rats. The amino acid methylated the glucocorticoid
gene, and the animals' behaviour changed. "They were almost exactly like the
poorly raised group," says Szyf, who announced his findings at a small
meeting on environmental epigenomics earlier this month in Durham, North
Carolina.

Though the experiment impaired well-adjusted animals, the opposite should be
possible, and Szyf has already shown that a chemical called TSA that is
designed to strip away methyl groups can turn a badly raised rat into a more
normal one.

No one is envisaging injecting supplements into people's brains, but Szyf
says his study shows how important subtle nutrients and supplements can be.
"Food has a dramatic effect," he says. "But it can go both ways," he
cautions. Methionine, for instance, the supplement he used to make healthy
rats stressed, is widely available in capsule form online or in health-food
stores - and the molecules are small enough to get into the brain via the
bloodstream.

Rob Waterland from Baylor College of Medicine in Houston, Texas, who
attended the meeting, says Szyf's ideas are creating a buzz, as they suggest
that methylation can influence our DNA well into adulthood. A huge number of
diseases are caused by changes to how our DNA is expressed, and this opens
up new ways of thinking about how to prevent and treat them, he says.

But Waterland points out there is still much work to be done. Substances
like methionine and TSA are, he says, a "sledgehammer approach", in that
they are likely to demethylate lots of genes, and we don't even know which
they will affect. But he speculates that techniques such as "RNA-directed
DNA methylation", so far tested only in plants but theoretically possible in
mammals, may allow us to target such methylation much more precisely.

[www.newscientist.com]

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