المؤلفون: Ralf Seidel, Anika Gonsberg, Sebastian Jung, Anna Dorothee Engelke, Michael Baier, Jörg Tatzelt, Sarah Ulbrich, Hermann M. Schätzl, Shaon Basu, Martin Engelhard, Konstanze F. Winklhofer, Gerd Multhaup, Simrika Thapa

مصطلحات موضوعية: 0301 basic medicine, Genetically modified mouse, Gene isoform, Amyloid, animal diseases, Scrapie, Mice, Transgenic, Biochemistry, Prion Proteins, Pathogenesis, 03 medical and health sciences, Mice, Neuroblastoma, 0302 clinical medicine, mental disorders, Tumor Cells, Cultured, Animals, Humans, Molecular Biology, Transition (genetics), Chemistry, Wild type, Molecular Bases of Disease, Cell Biology, Cell biology, nervous system diseases, Protein Transport, 030104 developmental biology, Protein Multimerization, 030217 neurology & neurosurgery, Intracellular, HeLa Cells

الوصف: A central step in the pathogenesis of prion diseases is the conformational transition of the cellular prion protein (PrP(C)) into the scrapie isoform, denoted PrP(Sc). Studies in transgenic mice have indicated that this conversion requires a direct interaction between PrP(C) and PrP(Sc); however, insights into the underlying mechanisms are still missing. Interestingly, only a subfraction of PrP(C) is converted in scrapie-infected cells, suggesting that not all PrP(C) species are suitable substrates for the conversion. On the basis of the observation that PrP(C) can form homodimers under physiological conditions with the internal hydrophobic domain (HD) serving as a putative dimerization domain, we wondered whether PrP dimerization is involved in the formation of neurotoxic and/or infectious PrP conformers. Here, we analyzed the possible impact on dimerization of pathogenic mutations in the HD that induce a spontaneous neurodegenerative disease in transgenic mice. Similarly to wildtype (WT) PrP(C), the neurotoxic variant PrP(AV3) formed homodimers as well as heterodimers with WTPrP(C). Notably, forced PrP dimerization via an intermolecular disulfide bond did not interfere with its maturation and intracellular trafficking. Covalently linked PrP dimers were complex glycosylated, GPI-anchored, and sorted to the outer leaflet of the plasma membrane. However, forced PrP(C) dimerization completely blocked its conversion into PrP(Sc) in chronically scrapie-infected mouse neuroblastoma cells. Moreover, PrP(C) dimers had a dominant-negative inhibition effect on the conversion of monomeric PrP(C). Our findings suggest that PrP(C) monomers are the major substrates for PrP(Sc) propagation and that it may be possible to halt prion formation by stabilizing PrP(C) dimers.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e622e1b6731705d2eafce9f32264c7ffTest
https://europepmc.org/articles/PMC5971439Test/

المؤلفون: Li Lu, Dalia H. A. Abdelaziz, Basant Abdulrahman, Alexander Zukiwski, Hermann M. Schätzl, Sabine Gilch, Simrika Thapa, Stefan Proniuk, Shubha Jain

المصدر: Scientific Reports
Scientific Reports, Vol 7, Iss 1, Pp 1-12 (2017)

مصطلحات موضوعية: 0301 basic medicine, Gene isoform, PrPSc Proteins, animal diseases, lcsh:Medicine, Stimulation, Article, Pathogenesis, 03 medical and health sciences, Mice, In vivo, Cell Line, Tumor, Autophagy, Animals, lcsh:Science, Neurons, Sulfonamides, Multidisciplinary, Chemistry, lcsh:R, In vitro, 3. Good health, Cell biology, nervous system diseases, 030104 developmental biology, Cell culture, Celecoxib, Pyrazoles, Protein folding, lcsh:Q

الوصف: Prion diseases are fatal infectious neurodegenerative disorders that affect both humans and animals. The autocatalytic conversion of the cellular prion protein (PrPC) into the pathologic isoform PrPSc is a key feature in prion pathogenesis. AR-12 is an IND-approved derivative of celecoxib that demonstrated preclinical activity against several microbial diseases. Recently, AR-12 has been shown to facilitate clearance of misfolded proteins. The latter proposes AR-12 to be a potential therapeutic agent for neurodegenerative disorders. In this study, we investigated the role of AR-12 and its derivatives in controlling prion infection. We tested AR-12 in prion infected neuronal and non-neuronal cell lines. Immunoblotting and confocal microscopy results showed that AR-12 and its analogue AR-14 reduced PrPSc levels after only 72 hours of treatment. Furthermore, infected cells were cured of PrPSc after exposure of AR-12 or AR-14 for only two weeks. We partially attribute the influence of the AR compounds on prion propagation to autophagy stimulation, in line with our previous findings that drug-induced stimulation of autophagy has anti-prion effects in vitro and in vivo. Taken together, this study demonstrates that AR-12 and the AR-14 analogue are potential new therapeutic agents for prion diseases and possibly protein misfolding disorders involving prion-like mechanisms.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c6ddae9b6f9daf9789254e13b49e292aTest
https://pubmed.ncbi.nlm.nih.gov/29242534Test