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Blood has been shown to contain disease-associated misfolded prion protein (PrP TSE ) in animals naturally and experimentally infected with various transmissible spongiform encephalopathy (TSE) agents, and in humans infected with variant Creutzfeldt–Jakob disease (vCJD). Recently, we have demonstrated PrP TSE in extracellular vesicle preparations (EVs) containing exosomes from plasma of mice infected with mouse-adapted vCJD by Protein Misfolding Cyclic Amplification (PMCA). Here we report the detection of PrP TSE by PMCA in EVs from plasma of mice infected with Fukuoka-1 (FU), an isolate from a Gerstmann–Sträussler–Scheinker disease patient. We used Tga20 transgenic mice that over-express mouse cellular prion protein, to assay by intracranial injections the level of infectivity in a FU-infected brain homogenate from wild-type mice (FU-BH), and in blood cellular components (BCC), consisting of red blood cells, white blood cells and platelets, plasma EVs, and plasma EVs subjected to multiple rounds of PMCA. Only FU-BH and plasma EVs from FU-infected mice subjected to PMCA that contained PrP TSE transmitted disease to Tga20 mice. Plasma EVs not subjected to PMCA and BCC from FU-infected mice failed to transmit disease. These findings confirm the high sensitivity of PMCA for PrP TSE detection in plasma EVs and the efficiency of this in vitro method to produce highly infectious prions. The results of our study encourage further research to define the role of EVs and, more specifically exosomes, as blood-borne carriers of PrP TSE . [ABSTRACT FROM AUTHOR]

Transmissible spongiform encephalopathies (TSEs) most commonly known as prion diseases are invariably fatal neurological disorders that affect humans and animals. These disorders differ from other neurodegenerative conformational diseases caused by the accumulation in the brain of misfolded proteins, sometimes with amyloid properties, in their ability to infect susceptible species by various routes. While the infectious properties of amyloidogenic proteins, other than misfolded prion protein (PrP TSE ), are currently under scrutiny, their potential to transmit from cell to cell, one of the intrinsic properties of the prion, has been recently shown in vitro and in vivo . Over the decades, various cell culture and laboratory animal models have been developed to study TSEs. These assays have been widely used in a variety of applications but showed to be time consuming and entailed elevated costs. Novel economic and fast alternatives became available with the development of in vitro assays that are based on the property of conformationally abnormal PrP TSE to recruit normal cellular PrP C to misfold. These include the cell-free conversion assay, protein misfolding cyclic amplification (PMCA) and quaking induced conversion assay (QuIC), of which the PMCA has been the only technology shown to generate infectious prions. Moreover, it allows indefinite amplification of PrP TSE with strain-specific biochemical and biological properties of the original molecules and under certain conditions may give rise to new spontaneously generated prions. The method also allows addressing the species barrier phenomena and assessing possible risks of animal-to-animal and animal-to-human transmission. Additionally, its unprecedented sensitivity has made possible the detection of as little as one infectious dose of PrP TSE and the biochemical identification of this protein in different tissues and biological fluids, including blood, cerebral spinal fluid (CSF), semen, milk, urine and saliva during the pre-clinical and clinical phases of the disease. The mechanistic similarities between TSEs and other conformational disorders have resulted in the adaptation of the PMCA to the amplification and detection of various amyloidogenic proteins. Here we provide a compelling discussion of the different applications of this technology to the study of TSEs and other neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the difference between the transmissible spongiform encephalopathies (TSEs), the risk of blood transfusion, and the surveillance for TSE-0implicated blood donors.

Transmissible spongiform encephalopathy (TSE) agents have contaminated human tissue-derived medical products, human blood components, and animal vaccines. The objective of this study was to determine the potential susceptibility to infection of 5 cell lines used or proposed for manufacture of biological products, as well as other lines. Cell lines were exposed to the infectious agents of sporadic and variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy (BSE). Exposed cultures were tested for TSE-associated prion protein (PrP[sup TSE]) and TSE infectivity by assay in rodents and nonhuman primates. No PrPTSE or infectivity has been detected in any exposed cell line under study so far. Animals inoculated with BSE brain homogenate developed typical spongiform encephalopathy. In contrast, animals inoculated with cells exposed to the BSE agent remained asymptomatic. All cell lines we studied resisted infection with 3 TSE agents, including the BSE agent. [ABSTRACT FROM AUTHOR]

BACKGROUND: The possible risk of iatrogenic transmissible spongiform encephalopathies (TSEs, prion diseases) from transplantation of marrow-derived mesenchymal stem cells (MSCs) is uncertain. While most cell lines resist infection, a few propagate TSE agents. STUDY DESIGN AND METHODS: We generated MSC-like (MSC-L) cell cultures from bone marrow (BM) of mice inoculated with the human-derived Fukuoka-1 (Fu) strain of TSE agent. Cultured cells were characterized for various markers and cellular prion protein (PrPC) by fluorescence-activated cell sorting and for PrPC and its pathologic TSE-associated form (PrPTSE) by Western blotting (WB). Cell cultures were tested for their susceptibility to infection with Fu in vitro. The infectivity of one Fu-infected cell culture was assayed in mice. RESULTS: BM cells from Fu-infected mice expressed neither PrPC nor PrPTSE after 3 days in culture as demonstrated by WB. Cells adherent to plastic and maintained under two different culture conditions became spontaneously immortalized and began to express PrPC at about the same time. One culture became transformed shortly after exposure to Fu in vitro and remained persistently infected, continuously generating PrPTSE through multiple passages; the infectivity of cultured cells was confirmed by intracerebral inoculation of lysates into mice. Both persistently TSE-infected and uninfected cells expressed a number of typical MSC markers. CONCLUSION: BM-derived MSC-L cells of mice became persistently infected with the Fu agent under certain conditions in culture-conditions that differ substantially from those currently used to develop investigational human stem cell therapies. [ABSTRACT FROM AUTHOR]

Background: The possible transmission of variant CJD (vCJD) through blood transfusion or use of plasma-derived products prompted this study comparing infectivity in murine models of vCJD and Gerstmann-Sträussler-Scheinker (GSS) disease, a non-vCJD form of transmissible spongiform encephalopathy (TSE).Study Design and Methods: RIII/Fa/Dk (RIII) or Swiss-Webster (Swiss) mice were inoculated intracerebrally (IC) with mouse-adapted strains of vCJD or GSS (Fukuoka-1) of similar infectivity. Groups of RIII mice were euthanized 17 weeks after inoculation (during the incubation period), and another 23 weeks after inoculation (when symptomatic). Blood was collected, separated into components, and inoculated into groups of healthy mice; brains and spleens from all mice were harvested and tested for the presence of PrPres by Western blot using 6H4 MoAb.Results: Levels of 20-30 infectious doses per mL were present in buffy coat and plasma during both the incubation and symptomatic stages of disease; PLT pellet infectivity was lower (10 ID/mL) and RBCs were not infectious. The disease was transmitted more efficiently by IV than IC inoculation of plasma, but there was no difference observed with inoculation of buffy coat. The incubation period was shorter after IC inoculation of GSS- than vCJD-brain inocula. The amount of PrPres in spleens was similar for both TSE agents, but was slightly lower in brains of vCJD than GSS mice.Conclusion: Infectivity was detected in blood components of mice infected with a human-derived strain of vCJD during both the preclinical and clinical phases of disease in a similarly low range of concentrations as in mice infected with a human-derived nonvariant strain (GSS, Fukuoka-1). Other measures of virulence, including brain infectivity titers, incubation periods, and the accumulation of PrPres in spleens and brains, were also comparable in both experimental models. [ABSTRACT FROM AUTHOR]

We have compared the induced expression of E-selectin in primary cultures of rat brain microvascular endothelial cells (EC), pericytes and in non-CNS microvascular endothelium stimulated with the cytokines, IL-1β (20 ng/ml), and tumor necrosis factor (TNF)-α (75 ng/ml). Expression was studied at both the protein and mRNA levels. Fluorescence in-situ hybridization (FISH) was used to examine de novo synthesis of E-selectin mRNA. Laser cytometric analysis was used as a novel approach to the quantitaion of FISH. In-situ hybridization was performed using two PCR-generated probes. The first probe (517 bp) spanned the lectin and epidermal growth factor (EGF)-like domain. The second probe (562 bp) spanned the CR3, 4, and 6 domains. E-selectin-specific mRNA was localized to the perinuclear regions of the EC. Both cytokines, IL-1β and TNF-α significantly increased E-selectin gene expression in CNS EC but not pericytes. IL-1β induced higher E-selectin mRNA levels than TNF-α. The maximum number of mRNA-positive cells was observed after stimulation for 4–6 h. Surface protein expression was sustained for up to 48 h following addition of cytokine. This was in contrast to the transient expression in non-CNS EC indicating that pure primary CNS EC display slightly different kinetics of E-selectin expression than non-CNS EC. [Copyright &y& Elsevier]

We report protease-resistant prion protein (PrPres) in spontaneous lymphoreticular tumors of mice infected with the agent of variant Creutzfeldt-Jakob disease (vCJD). PrPres may accumulate in lymphoreticular system tumors of asymptomatic persons with vCJD. The statistical power of estimates of vCJD prevalence might be increased by expanding screening to include samples of lymphoreticular neoplasms. [ABSTRACT FROM AUTHOR]

Presents information on phenotype-genotype studies in kuru, the prototype human transmissible spongiform encephalopathy (TSE). Discussion on the a variant of the Creutzfeldt-Jakob disease (nvCJD); Methodology used in conducting the study; Distribution of homozygous methionine, homozygous valine and heterozygous genotypes.

Presents a letter to the editor about acronyms used for proteinaceous-infectious particles.

Although the literature on convalescent plasma treatment of COVID-19 is scarce, a few recent publications described positive outcomes in a small number of patients (27 total cases), mainly in critical conditions, who received convalescent plasma from COVID-19 recovered persons [4-8]. DOI: 10.1111/voxs.12571 Industry call for COVID-19 convalescent plasma collections Amy Chevalier Efantis, Brenna Raines & Larisa Cervenakova Plasma Protein Therapeutics Association, Annapolis, MD, USA To the Editor The treatment of COVID-19 patients, especially in severe conditions, presents a challenge to medical professionals. [Extracted from the article]

To assess the risk of the de novo emergence of the agent of transmissible spongiform encephalopathies in cultured cells, we examined the stability of the prion protein-encoding (PRNP) gene in HeLa cells and in cultures contaminated with HeLa cells that have been passaged extensively for over 50 years. Various sub-lineages of HeLa cells showed that some contained a mixture of a truncated PRNP gene (R3–R4 deletion) and a full-length PRNP gene, while others were homozygous for the R3–R4 deletion. That finding suggests that the progenitor of several popular sub-lineages of HeLa must have lost part or all of chromosome 20 early in the history of HeLa cells. No mutations were found in the PRNP genes. We conclude that the spontaneous appearance of mutations leading to expression of abnormal prion proteins in continuously passaged heteroploid cell lines is unlikely to pose a substantial risk for the safe production of biologicals in such cells. [Copyright &y& Elsevier]

Studies the ancestral origins and worldwide distribution of the PRNP 200K mutation causing familial Creutzfeldt-Jakob disease (CDJ). Selection of microsatellite markers on the PRNP gene on chromosome 20p12-pter and an intragenic single-nucleotide polymorphism at the PRNP codon 129; Role of founder effect and independent mutational events for the geographic distribution of heridatary CJD associated with the 200K mutation.

Background information: Cellular prion protein (PrPC) is infamous for its role in prion diseases. The physiological function of PrPC remains enigmatic, but several studies point to its involvement in cell differentiation processes. To test this possibility, we monitored PrPC changes during the differentiation of prion‐susceptible CAD 5 cells, and then we analysed the effect of PrPC ablation on the differentiation process. Results: Neuronal CAD 5 cells differentiate within 5 days of serum withdrawal, with the majority of the cells developing long neurites. This process is accompanied by an up to sixfold increase in PrPC expression and enhanced N‐terminal β‐cleavage of the protein, which suggests a role for the PrPC in the differentiation process. Moreover, the majority of PrPC in differentiated cells is inside the cell, and a large proportion of the protein does not associate with membrane lipid rafts. In contrast, PrPC in proliferating cells is found mostly on the cytoplasmic membrane and is predominantly associated with lipid rafts. To determine the importance of PrPC in cell differentiation, a CAD 5 PrP−/− cell line with ablated PrPC expression was created using the CRISPR/Cas9 system. We observed no considerable difference in morphology, proliferation rate or expression of molecular markers between CAD 5 and CAD 5 PrP−/− cells during the differentiation initiated by serum withdrawal. Conclusions: PrPC characteristics, such as cell localisation, level of expression and posttranslational modifications, change during CAD 5 cell differentiation, but PrPC ablation does not change the course of the differentiation process. Significance: Ablation of PrPC expression does not affect CAD 5 cell differentiation, although we observed many intriguing changes in PrPC features during the process. Our study does not support the concept that PrPC is important for neuronal cell differentiation, at least in simple in vitro conditions. [ABSTRACT FROM AUTHOR]

The development of variant Creutzfeldt-Jakob disease (vCJD) in three recipients of non-leukoreduced red blood cells from asymptomatic donors who subsequently developed the disease has confirmed existing concerns about the possible spread of transmissible spongiform encephalopathies (TSEs) via blood products. In addition, the presence of disease-associated misfolded prion protein (PrPTSE), generally associated with infectivity, has been demonstrated in the blood of vCJD patients. However, its origin and distribution in this biological fluid are still unknown. Various studies have identified cellular prion protein (PrPC) among the protein cargo in human blood-circulating extracellular vesicles released from endothelial cells and platelets, and exosomes isolated from the conditioned media of TSE-infected cells have caused the disease when injected into experimental mice. In this study, we demonstrate the detection of PrPTSE in extracellular vesicles isolated from plasma samples collected during the preclinical and clinical phases of the disease from mice infected with mouse-adapted vCJD and confirm the presence of the exosomal marker Hsp70 in these preparations. [ABSTRACT FROM AUTHOR]

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy, or prion disease, that affects deer, elk, and moose. Human susceptibility to CWD remains unproven despite likely exposure to CWD-infected cervids. We used 2 nonhuman primate species, cynomolgus macaques and squirrel monkeys, as human models for CWD susceptibility. CWD was inoculated into these 2 species by intracerebral and oral routes. After intracerebral inoculation of squirrel monkeys, 7 of 8 CWD isolates induced a clinical wasting syndrome within 33-53 months. The monkeys' brains showed spongiform encephalopathy and proteaseresistant prion protein (PrPres) diagnostic of prion disease. After oral exposure, 2 squirrel monkeys had PrPres in brain, spleen, and lymph nodes at 69 months postinfection. In contrast, cynomolgus macaques have not shown evidence of clinical disease as of 70 months postinfection. Thus, these 2 species differed in susceptibility to CWD. Because humans are evolutionarily closer to macaques than to squirrel monkeys, they may also be resistant to CWD. [ABSTRACT FROM AUTHOR]

BACKGROUND: The long-standing goal of a preclinical diagnostic test for transmissible spongiform encephalopathy (TSE) has recently become urgent because of the discovery that humans with variant Creutzfeldt-Jakob disease can transmit disease via blood transfusions. STUDY DESIGN AND METHODS: The misfolded protein diagnostic (MPD) assay employs a pyrene-labeled palindromic sequence of prion peptides that undergoes a cascade of coil to β-sheet conversion in the presence of the misfolded prion protein (PrPTSE). The ability of the assay to detect PrPTSE in brain, serum, and plasma was tested. The basic protocol involved a several-hour incubation of 200-µL sample volumes with the peptide reagent in 96-well plates, after which fluorescence was monitored by a fluorescence plate reader with an excitation wavelength of 350 nm and emission scanning wavelength range of 365 to 600 nm. RESULTS: Target specificity for PrPTSE was documented by correlation of assay signal with Western blot signals in brain tissue from TSE-infected, normal, and knockout mice and negative assay signals by use of reagents with different peptide sequences. When applied to plasma or serum, the assay discriminated between samples from a variety of experimental and natural TSE infections compared to uninfected controls, with a sensitivity threshold of approximately 1 infectious dose per mL in pooled plasma from TSE-infected mice. CONCLUSIONS: The MPD assay is a sensitive and specific test for the detection of PrPTSE that may be useful in both preclinical and clinical diagnosis of TSE diseases of animals and humans. [ABSTRACT FROM AUTHOR]

Kuru reached epidemic proportions by the mid-twentieth century among the Fore people of New Guinea and disappeared after the abolition of cannibalistic rituals. To determine susceptibility to kuru and its role in the spread and elimination of the epidemic, we analyzed the PRNP gene coding sequences in 5 kuru patients; no germline mutations were found. Analysis of the PRNP 129 methionine (M)/valine (V) polymorphism in 80 patients and 95 unaffected controls demonstrated that the kuru epidemic preferentially affected individuals with the M/M genotype. A higher representation of M/M carriers was observed among the affected young Fore males entering the age of risk, whereas a lower frequency of M/M homozygotes was found among the survivors. M/V and V/V genotypes predisposed to a lower risk of disease development and longer incubation times. These findings are relevant to the current outbreak of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom, because all vCJD patients tested thus far have been M/M carriers. [ABSTRACT FROM AUTHOR]

The transmission of variant Creutzfeldt-Jakob disease (vCJD) through blood transfusions has created new concerns about the iatrogenic spread of transmissible spongiform encephalopathies (TSEs)/prion diseases through blood and plasma-derived products and has increased the need to develop efficient methods for detection of the agent in biologics. Here, we report the first successful generation of spleen-derived murine stromal cell cultures that persistently propagate two mouse-adapted isolates of human TSE agents, mouse-adapted vCJD, and Fukuoka 1. These new cell cultures can be used efficiently for studies of the pathogenesis of the disease, for development of diagnostics and therapeutics, and as a rapid ex vivo assay for TSE inactivation/removal procedures. [ABSTRACT FROM AUTHOR]