ISLAMABAD: A newly discovered "survival protein" protects the brain
against the effects of stroke by interfering with a particular kind of
brain cell death that is often found in cases of Parkinson’s disease
and heart attack.
Scientists from Johns Hopkins University in
the US say they exploited the fact that when brain tissue is subjected
to a stressful but not lethal effect, a defence response occurs that
protects cells from subsequent effects.
The scientists
dissected this preconditioning pathway to identify the most critical
molecular players, one of which is the newly identified protein
protector called Iduna, reports the journal Nature Medicine.
Named
for a mythological Norwegian goddess who guards a tree full of golden
apples used in restoring health to sick and injured gods, the Iduna
protein increased three-to four-fold in preconditioned mouse brain
tissue, according to the scientists.
"Apparently, what doesn’t
kill you makes you stronger," says Valina Dawson, professor of
neurology and neuroscience at the Johns Hopkins Institute of Cell
Engineering.
"This protective response was broad in its defence
of neurons and glia and blood vessels - the entire brain. It’s not just
a delay of death, but real protection that lasts for about 72 hours,"
adds Dawson, according to a Johns Hopkins statement.
The team
noted that Iduna works by interrupting a cascade of molecular events
that result in a common and widespread type of brain cell death called
parthanatos often found in cases of stroke, Parkinson’s disease,
diabetes and heart attack.
By binding with a molecule known as
PAR polymer, Iduna prevents the movement of cell-death-inducing factor
(AIF) into a cell’s nucleus.
In some of the experiments, Dawson
and her team exposed mouse brain cells to short bursts of a toxic
chemical, and then screened these "preconditioned" cells for genes that
turned on as a result.
Focusing on Iduna, the researchers
turned up the gene’s activity in the cells during exposure to the toxic
chemical that induced preconditioning.
Cells deficient in Iduna did not survive, but those with more Iduna did. Online
