de novo generation of infectious prions in vitro produces a new disease phenotype新创一代感染朊病毒在体外产生一种新的疾病表型.pdf

De Novo Generation of Infectious Prions In Vitro Produces a New Disease Phenotype Marcelo A. Barria1,2, Abhisek Mukherjee1,2, Dennisse Gonzalez-Romero1,2, Rodrigo Morales 1,2,3, Claudio Soto1,2* 1 George and Cynthia Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America, 2 Department of Neurology, University of Texas Houston Medical School, Houston, Texas, United States of America, 3 Facultad de Ciencias, University of Chile, Santiago, Chile Abstract Prions are the proteinaceous infectious agents responsible for Transmissible Spongiform Encephalopathies. Compelling evidence supports the hypothesis that prions are composed exclusively of a misfolded version of the prion protein (PrPSc) that replicates in the body in the absence of nucleic acids by inducing the misfolding of the cellular prion protein (PrPC). The most common form of human prion disease is sporadic, which appears to have its origin in a low frequency event of spontaneous misfolding to generate the first PrPSc particle that then propagates as in the infectious form of the disease. The main goal of this study was to mimic an early event in the etiology of sporadic disease by attempting de novo generation of infectious PrPSc in vitro. For this purpose we analyzed in detail the possibility of spontaneous generation of PrPSc by the protein misfolding cyclic amplification (PMCA) procedure. Under standard PMCA conditions, and taking precautions to avoid cross-contamination, de novo generation of PrPSc was never observed, supporting the use of the technology for diagnostic applications. However, we report that PMCA can be modified to generate PrPSc in the absence of pre-existing PrPSc in different animal species at a low and variable rate. De novo generated PrPS