PMCA for ultrasensitive detection of prions and to study disease biology

Abstract

The emergence of a novel class of infectious agent composed exclusively of a misfolded protein (termed prions) has been a challenge in modern biomedicine. Despite similarities on the behavior of prions with respect to conventional pathogens, the many uncertainties regarding the biology and virulence of prions make them a worrisome paradigm. Since prions do not contain nucleic acids and rely on a very different way of replication and spreading, it was necessary to invent a novel technology to study them. In this article, we provide an overview of such a technology, termed protein misfolding cyclic amplification (PMCA), and summarize its many applications to detect prions and understand prion biology.

Detection of prions in the urine of patients affected by sporadic Creutzfeldt–Jakob disease

“…Detection of sCJD prions by PMCA has usually yielded a rather low rate of amplification, contrasting the ultrasensitive detection of vCJD by this technique 4,5 . Thus, first we tested several modifications of the PMCA procedure to increase amplification efficiency.…”

“…Despite impressive advances in the knowledge about the molecular and cellular basis of CJD, the disease remains incurable and without any treatment option to offer to patients. One of largest problems to develop an efficient treatment is that when prion diseases manifest clinically, a substantial part of the brain is severely and irreversibly damaged, making very difficult to produce a therapeutic benefit 4 . It is likely that the best option would be to identify people on the way to develop CJD before they develop clinical symptoms and substantial damage in the brain.…”

“…Here, we used an ultrasensitive test for prion detection, termed protein misfolding cyclic amplification (PMCA), 4,16 to study whether PrP Sc is detectable in urine samples from patients affected by six common subtypes of sCJD.…”

New developments in prion disease research

“…Protein misfolding cyclic amplification, or short PMCA, was the first ultrasensitive prion amplification method to be established. Claudio Soto, the inventor of this technology, and his colleagues provide an overview of the technology and summarize its applications to detect prions for diagnostic and research purposes (Wang et al 2022). Finally, Standke and Kraus provide a state-of-the-art overview on how RT-QuIC can be used to detect disease-specific protein seeds in other neurodegenerative diseases, with a focus on diagnostic RT-QuIC assays and the insights these readouts provide into seed structures and strain differences (Standke and Kraus 2022).…”