EurekAlert
July 26, 2010
JUPITER, FL - In a startling new study that involved research on both sides of the Atlantic, scientists from The Scripps Research Institute in Florida and the University College London (UCL) Institute of Neurology in England have shown for the first time that abnormal prions, bits of infectious protein devoid of DNA or RNA that can cause fatal neurodegenerative disease, can suddenly erupt from healthy brain tissue.
The catalyst in the study was the metallic surface of simple steel wires. Previous research showed that prions bind readily to these types of surfaces and can initiate infection with remarkable efficiency. Surprisingly, according to the new research, wires coated with uninfected brain homogenate could also initiate prion disease in cell culture, which was transmissible to mice.
The findings are being published the week of July 26, 2010, in an advance, online edition of the journal Proceedings of the National Academy of Sciences (PNAS).
"Prion diseases such as sporadic Creutzfeldt-Jakob disease in humans or atypical bovine spongiform encephalopathy, a form of mad cow disease, occur rarely and at random," said Charles Weissmann, M.D., Ph.D., chair of Scripps Florida's Department of Infectology, who led the study with John Collinge, head of the Department of Neurodegenerative Disease at UCL Institute of Neurology. "It has been proposed that these events reflect rare, spontaneous formation of prions in brain. Our study offers experimental proof that prions can in fact originate spontaneously, and shows that this event is promoted by contact with steel surfaces."
Infectious prions, which are composed solely of protein, are classified by distinct strains, originally characterized by their incubation time and the disease they cause. These toxic prions have the ability to reproduce, despite the fact that they contain no nucleic acid genome.
Mammalian cells normally produce harmless cellular prion protein (PrPC). Following prion infection, the abnormal or misfolded prion protein (PrPSc) converts PrPC into a likeness of itself, by causing it to change its conformation or shape. The end-stage consists of large aggregates of these misfolded proteins, which cause massive tissue and cell damage.
Full text:
http://www.eurekalert.org/pub_releases/2010-07/sri-srs072610.php
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