Past, Present and Potential Future Prion Disease Treatment Strategies

The prion diseases are rare and invariably fatal neurodegenerative diseases characterized by a unique, protein‐only pathogenesis. Mechanistically, the prion diseases result from the coerced conversion of a protease‐sensitive form of the cellular prion protein (PrPC) into a protease‐resistant infectious form (PrPres). This chapter reviews the past, present, and potentially future prion disease treatment strategies. This chapter begins with an introduction to prion diseases, the misfolding of prion proteins and what is known about this process, and then proceeds to discuss approaches for treatments. Regarding approaches to treat prion diseases, we discuss (1) small molecule inhibitors, (2) antiprion protein antibodies, (3) prion gene disruption, (4) targeting of the unfolded protein response, and (5) heterologous prion proteins. We elaborate on using heterologous prion proteins to treat prion diseases, as this is an area that we are pursuing. The chapter ends with thoughts on the future direction of prion disease treatment strategies and how these strategies might be applicable to other neurodegenerative diseases involving protein misfolding. The increasing awareness of the role of protein misfolding in many neurodegenerative processes makes the development of an effective treatment strategy for prion diseases a high priority

Neurobehavioral Testing in Prion Disease Studies

The prion diseases are neurodegenerative diseases characterized by progressive neurocognitive decline and terminal dementia. In this review, we will discuss the role of neurobehavioral testing in mammalian prion disease model systems, including (1) a review of the clinical phenotype of the major prion diseases in natural disease, (2) an evidence-based summary of the benefits and shortcomings of commonly used behavioral assays, and (3) a review of the neurobehavioral testing in rodent prion models. Based upon this review, and in light of the established importance of model systems in studies of prion pathogenesis and the proven role of behavioral testing in nonprion disease neurodegenerative diseases, it is vital that prion researchers consider the clinical consequences of prion infection so as to maximize the impact of their work

A reassessment of Antarctic plateau reactive nitrogen based on ANTCI 2003 airborne and ground based measurements

The first airborne measurements of nitric oxide (NO) on the Antarctic plateau have demonstrated that the previously reported elevated levels of this species extend well beyond the immediate vicinity of South Pole. Although the current database is still relatively weak and critical laboratory experiments are still needed, the findings here suggest that the chemical uniqueness of the plateau may be substantially greater than first reported. For example, South Pole ground-based findings have provided new evidence showing that the dominant process driving the release of nitrogen from the snowpack during the spring/summer season (post-depositional loss) is photochemical in nature with evaporative processes playing a lesser role. There is also new evidence suggesting that nitrogen, in the form of nitrate, may undergo multiple recycling within a given photochemical season. Speculation here is that this may be a unique property of the plateau and much related to its having persistent cold temperatures even during summer. These conditions promote the efficient adsorption of molecules like HNO3 (and very likely HO2NO2) onto snow-pack surface ice where we have hypothesized enhanced photochemical processing can occur, leading to the efficient release of NOx to the atmosphere. In addition, to these process-oriented tentative conclusions, the findings from the airborne studies, in conjunction with modeling exercises suggest a new paradigm for the plateau atmosphere. The near-surface atmosphere over this massive region can be viewed as serving as much more than a temporary reservoir or holding tank for imported chemical species. It defines an immense atmospheric chemical reactor which is capable of modifying the chemical characteristics of select atmospheric constituents. This reactor has most likely been in place over geological time, and may have led to the chemical modulation of some trace species now found in ice cores. Reactive nitrogen has played a critical role in both establishing and in maintaining this reactor. © 2007 Elsevier Ltd. All rights reserved

Detection of CWD Prions in Urine and Saliva of Deer by Transgenic Mouse Bioassay

Chronic wasting disease (CWD) is a prion disease affecting captive and free-ranging cervids (e.g. deer, elk, and moose). The mechanisms of CWD transmission are poorly understood, though bodily fluids are thought to play an important role. Here we report the presence of infectious prions in the urine and saliva of deer with chronic wasting disease (CWD). Prion infectivity was detected by bioassay of concentrated, dialyzed urine and saliva in transgenic mice expressing the cervid PrP gene (Tg[CerPrP] mice). In addition, PrP(CWD) was detected in pooled and concentrated urine by protein misfolding cyclic amplification (PMCA). The concentration of abnormal prion protein in bodily fluids was very low, as indicated by: undetectable PrP(CWD) levels by traditional assays (western blot, ELISA) and prolonged incubation periods and incomplete TSE attack rates in inoculated Tg(CerPrP) mice (373(+/-)3 days in 2 of 9 urine-inoculated mice and 342(+/-)109 days in 8 of 9 saliva-inoculated mice). These findings help extend our understanding of CWD prion shedding and transmission and portend the detection of infectious prions in body fluids in other prion infections

Ionizing Radiation Increases Type I Collagen Matrix Production and May Contribute to Pulmonary Fibrosis

Faculty advisor: Richard NhoThis research was supported by the Undergraduate Research Opportunities Program (UROP)

Mother to offspring transmission of chronic wasting disease in Reeves' Muntjac deer

The horizontal transmission of prion diseases has been well characterized in bovine spongiform encephalopathy (BSE), chronic wasting disease (CWD) of deer and elk and scrapie of sheep, and has been regarded as the primary mode of transmission. Few studies have monitored the possibility of vertical transmission occurring within an infected mother during pregnancy. To study the potential for and pathway of vertical transmission of CWD in the native cervid species, we used a small cervid model-the polyestrous breeding, indoor maintainable, Reeves' muntjac deer-and determined that the susceptibility and pathogenesis of CWD in these deer reproduce that in native mule and white-tailed deer. Moreover, we demonstrate here that CWD prions are transmitted from doe to fawn. Maternal CWD infection also appears to result in lower percentage of live birth offspring. In addition, evolving evidence from protein misfolding cyclic amplification (PMCA) assays on fetal tissues suggest that covert prion infection occurs in utero. Overall, our findings demonstrate that transmission of prions from mother to offspring can occur, and may be underestimated for all prion diseases

Spectroscopic studies as a toolbox for biophysical and chemical characterization of lipid-based nanotherapeutics

The goal of this study is to provide tools to minimize trial-and-error in the development of novel lipid-based nanotherapeutics, in favor of a rational design process. For this purpose, we present case-study examples of biophysical assays that help addressing issues of lipid-based nanotherapeutics' profiling and assist in the design of lipid nanocarriers for therapeutic usage. The assays presented are rooted in spectroscopic methods (steady-state and time-resolved fluorescence; UV-Vis derivative spectroscopy; fluorescence anisotropy and fluorescence lifetime image microscopy) and allow accessing physical-chemical interactions between drugs and lipid nanocarriers, as well as studying interactions between lipid-based nanotherapeutics and membranes and/or proteins, as this is a key factor in predicting their therapeutic and off target effects. Derivative spectroscopy revealed Naproxen's high distribution (LogD ≈ 3) in different lipid-based nanocarriers (micelles and unilamellar or multilamellar vesicles) confirming the adequacy of such systems for encapsulating this anti-inflammatory drug. Fluorescence quenching studies revealed that the anti-inflammatory drugs Acemetacin and Indomethacin can reach an inner location at the lipid nanocarrier while being anchored with its carboxylic moiety at the polar headgroup. The least observed quenching effect suggested that Tolmetin is probably located at the polar headgroup region of the lipid nanocarriers and this superficial location may translate in a fast drug release from the nanocarriers. Fluorescent anisotropy measurements indicated that the drugs deeply buried within the lipid nanocarrier where the ones that had a greater fluidizing effect which can also translate in a faster drug release. The drug binding strength to serum albumin was also compared for a free drug (Clonixin) or for the same drug after encapsulation in a lipid nanocarrier DSPC:DODAP (2:1). Under both conditions there is a strong binding to serum albumin, at one binding site, suggesting the need to produce a stealth nanosystem. Finally the cellular uptake of lipid nanocarriers loaded with Daunorubicin was investigated in cancer cells using fluorescence lifetime imaging microscopy. From the images obtained it was possible to conclude that even at short incubation times (15 min) there was a distribution of the drug in the cytoplasm, whereas for longer incubation periods (4 h) the drug has reached the nucleus.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and in the ambit of the project IF/00498/2012