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.
A Highly Sensitive Test
In the new study, the scientists used the Scrapie Cell Assay, a test originally created by Weissmann that is highly sensitive to minute quantities of prions.
Using the Scrapie Cell Assay to measure infectivity of prion-coated wires, the team observed several unexpected instances of infectious prions in control groups where metal wires had been exposed only to uninfected normal mouse brain tissue. In the current study, this phenomenon was investigated in rigorous and exhaustive control experiments specifically designed to exclude prion contamination. Weissmann and his colleagues in London found that when normal prion protein is coated onto steel wires and brought into contact with cultured cells, a small but significant proportion of the coated wires cause prion infection of the cells – and when transferred to mice, they continue to spawn the disease.
Weissmann noted that an alternative interpretation of the results is that infectious prions are naturally present in the brain at levels not detectable by conventional methods, and are normally destroyed at the same rate they are created. If that is the case, he noted, metal surfaces could be acting to concentrate the infectious prions to the extent that they became quantifiable by the team's testing methods.
The first author of the study, "Spontaneous Generation of Mammalian Prions," is Julie Edgeworth of the UCL Institute of Neurology. Other authors of the study include Nathalie Gros, Jack Alden, Susan Joiner, Jonathan D.F. Wadsworth, Jackie Linehan, Sebastian Brandner, and Graham S. Jackson, also of the UCL Institute of Neurology.
The study was supported by the U.K. Medical Research Council.
About The Scripps Research Institute
The Scripps Research Institute is one of the world's largest independent, non-profit biomedical research organizations, at the forefront of basic biomedical science that seeks to comprehend the most fundamental processes of life. Scripps Research is internationally recognized for its discoveries in immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune, cardiovascular, and infectious diseases, and synthetic vaccine development. Established in its current configuration in 1961, it employs approximately 3,000 scientists, postdoctoral fellows, scientific and other technicians, doctoral degree graduate students, and administrative and technical support personnel. Scripps Research is headquartered in La Jolla, California. It also includes Scripps Florida, whose researchers focus on basic biomedical science, drug discovery, and technology development. Scripps Florida is located in Jupiter, Florida. See www.scripps.edu
Mika Ono | EurekAlert!
Do microplastics harbour additional risks by colonization with harmful bacteria?
05.04.2018 | Leibniz-Institut für Ostseeforschung Warnemünde
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy