scholarly journals Subclinical Prion Disease Induced by Oral Inoculation

2003 ◽  
Vol 77 (14) ◽  
pp. 7991-7998 ◽  
Author(s):  
Alana M. Thackray ◽  
Michael A. Klein ◽  
Raymond Bujdoso
Keyword(s):  
Nervous System ◽  
Protein Expression ◽  
Prion Disease ◽  
Clinical Signs ◽  
Oral Route ◽  
Wild Type ◽  
Subclinical Disease ◽  
Oral Inoculation ◽  
The Central Nervous System ◽  
Peripheral Infection

ABSTRACT Natural transmission of prion disease is believed to occur by peripheral infection such as oral inoculation. Following this route of inoculation, both the peripheral nervous system and the lymphoreticular system may be involved in the subsequent neuroinvasion of the central nervous system by prions, which may not necessarily result in clinical signs of terminal disease. Subclinical prion disease, characterized by the presence of infectivity and PrPSc in the absence of overt clinical signs, may occur. It is not known which host factors contribute to whether infection with prions culminates in a terminal or subclinical disease state. We have investigated whether the level of host PrPc protein expression is a factor in the development of subclinical prion disease. When RML prion inoculum was inoculated by either the i.c. or intraperitoneal route, wild-type and tga20 mice both succumbed to terminal prion disease. In contrast, orally inoculated tga20 mice succumbed to terminal prion disease, whereas wild-type mice showed no clinical signs. However, wild-type mice sacrificed 375 or 525 days after oral inoculation harbored significant levels of brain PrPSc and infectivity. These data show that same-species transmission of prions by the oral route in animals that express normal levels of PrPc can result in subclinical prion disease. This indicates that the level of host PrPc protein expression is a contributing factor to the regulation of development of terminal prion disease. Events that increase PrPc expression may predispose a prion-infected animal to the more deleterious effects of prion pathology.

scholarly journals Microglia Are Critical in Host Defense against Prion Disease

2018 ◽  
Vol 92 (15) ◽  
Author(s):  
James A. Carroll ◽  
Brent Race ◽  
Katie Williams ◽  
James Striebel ◽  
Bruce Chesebro
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Prion Disease ◽  
Host Defense ◽  
Clinical Signs ◽  
Clinical Disease ◽  
Oral Drug ◽  
Early Event ◽  
Prion Infection ◽  
The Central Nervous System

ABSTRACT Microglial cells in the central nervous system play important roles in neurodevelopment and resistance to infection, yet microglia can become neurotoxic under some conditions. An early event during prion infection is the activation of microglia and astrocytes in the brain prior to damage or death of neurons. Previous prion disease studies using two different strategies to manipulate signaling through the microglial receptor CSF-1R reported contrary effects on survival from prion disease. However, in these studies, reductions of microglial numbers and function were variable, thus confounding interpretation of the results. In the present work, we used oral treatment with a potent inhibitor of CSF-1R, PLX5622, to eliminate 78 to 90% of microglia from cortex early during the course of prion infection. Oral drug treatment early after infection with the RML scrapie strain significantly accelerated vacuolation, astrogliosis, and deposition of disease-associated prion protein. Furthermore, drug-treated mice had advanced clinical disease requiring euthanasia 31 days earlier than untreated control mice. Similarly, PLX5622 treatment during the preclinical phase at 80 days postinfection with RML scrapie also accelerated disease and resulted in euthanasia of mice 33 days earlier than infected controls. PLX5622 also accelerated clinical disease after infection with scrapie strains ME7 and 22L. Thus, microglia are critical in host defense during prion disease. The early accumulation of PrPSc in the absence of microglia suggested that microglia may function by clearing PrPSc, resulting in longer survival. IMPORTANCE Microglia contribute to many aspects of health and disease. When activated, microglia can be beneficial by repairing damage in the central nervous system (CNS) or they can turn harmful by becoming neurotoxic. In prion and prionlike diseases, the involvement of microglia in disease is unclear. Previous studies suggest that microglia can either speed up or slow down disease. In this study, we infected mice with prions and depleted microglia from the brains of mice using PLX5622, an effective CSF-1R tyrosine kinase inhibitor. Microglia were markedly reduced in brains, and prion disease was accelerated, so that mice needed to be euthanized 20 to 33 days earlier than infected control mice due to advanced clinical disease. Similar results occurred when mice were treated with PLX5622 at 80 days after infection, which was just prior to the start of clinical signs. Thus, microglia are important for removing prions, and the disease is faster when microglia are depleted.

scholarly journals Distribution of the prion protein in sheep terminally affected with BSE following experimental oral transmission

2001 ◽  
Vol 82 (10) ◽  
pp. 2319-2326 ◽  
Author(s):  
J. D. Foster ◽  
D. W. Parnham ◽  
N. Hunter ◽  
M. Bruce
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Experimental Infection ◽  
Oral Route ◽  
Similar Distribution ◽  
Peripheral Tissues ◽  
Oral Transmission ◽  
Wide Range ◽  
Direct Contrast ◽  
The Central Nervous System

This study has examined the distribution of PrPSc in sheep by immunocytochemistry of tissues recovered from terminally affected animals following their experimental infection by the oral route with BSE. Despite a wide range of incubation period lengths, affected sheep showed a similar distribution of high levels of PrPSc throughout the central nervous system. PrPSc was also found in the lymphoid system, including parts of the digestive tract, and some components of the peripheral nervous system. These abundant PrPSc deposits in sheep in regions outside the central nervous system are in direct contrast with cattle infected with BSE, which show barely detectable levels of PrPSc in peripheral tissues. A number of genetically susceptible, challenged animals appear to have survived.

Degeneration of skeletal muscle, peripheral nerves, and the central nervous system in transgenic mice overexpressing wild-type prion proteins

Cell ◽  
1994 ◽  
Vol 76 (1) ◽  
pp. 117-129 ◽  
Author(s):  
David Westaway ◽  
Stephen J. DeArmond ◽  
Juliana Cayetano-Canlas ◽  
Darlene Groth ◽  
Dallas Foster ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Peripheral Nerves ◽  
Prion Proteins ◽  
Wild Type ◽  
The Central Nervous System

scholarly journals Delayed development of specific thyroid hormone-regulated events in transthyretin null mice

2013 ◽  
Vol 304 (1) ◽  
pp. E23-E31 ◽  
Author(s):  
Julie A. Monk ◽  
Natalie A. Sims ◽  
Katarzyna M. Dziegielewska ◽  
Roy E. Weiss ◽  
Robert G. Ramsay ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
Thyroid Hormone ◽  
Bone Growth ◽  
Circulatory System ◽  
Goblet Cells ◽  
Wild Type ◽  
The Central Nervous System ◽  
Delayed Growth

Thyroid hormones (THs) are vital for normal postnatal development. Extracellular TH distributor proteins create an intravascular reservoir of THs. Transthyretin (TTR) is a TH distributor protein in the circulatory system and is the only TH distributor protein synthesized in the central nervous system. We investigated the phenotype of TTR null mice during development. Total and free 3′,5′,3,5-tetraiodo-l-thyronine (T4) and free 3′,3,5-triiodo-l-thyronine (T3) in plasma were significantly reduced in 14-day-old (P14) TTR null mice. TTR null mice also displayed a delayed suckling-to-weaning transition, decreased muscle mass, delayed growth, and retarded longitudinal bone growth. In addition, ileums from postnatal day 0 (P0) TTR null mice displayed disordered architecture and contained fewer goblet cells than wild type. Protein concentrations in cerebrospinal fluid from P0 and P14 TTR null mice were higher than in age-matched wild-type mice. In contrast to the current literature based on analyses of adult TTR null mice, our results demonstrate that TTR has an important and nonredundant role in influencing the development of several organs.

The Neuroimmune Interface in Prion Diseases

Physiology ◽  
2000 ◽  
Vol 15 (5) ◽  
pp. 250-255
Author(s):  
Michael A. Klein ◽  
Adriano Aguzzi
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Immune System ◽  
Prion Disease ◽  
Neurodegenerative Disorders ◽  
Prion Diseases ◽  
The Central Nervous System

Prion diseases are fatal neurodegenerative disorders of animals and humans. Here we address the role of the immune system in the spread of prions from peripheral sites to the central nervous system and its potential relevance to iatrogenic prion disease.

scholarly journals Presence of amastigotes in the central nervous system of hamsters infected with Leishmania sp.

2011 ◽  
Vol 20 (2) ◽  
pp. 97-102 ◽  
Author(s):  
Elisangela de Oliveira ◽  
Elisa Teruya Oshiro ◽  
Rebeca Vieira Pinto ◽  
Bruna Corrêa de Castro ◽  
Karla Borges Daniel ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Clinical Signs ◽  
Direct Examination ◽  
Mato Grosso ◽  
The Central Nervous System ◽  
Animal House ◽  
Immunohistochemical Studies ◽  
Negative Controls ◽  
The Brain

Visceral leishmaniasis (VL) is a severe chronic disease caused by Leishmania (Leishmania) infantum chagasi. Better knowledge on the effects caused by this disease can help develop adequate clinical management and treatment. Parasitological and immunohistochemical studies were performed golden hamsters Mesocricetus auratus infected with bone marrow from individuals with VL in the State of Mato Grosso do Sul, central-west Brazil. The effects of parasitism in the spleen, liver, kidneys, lungs, heart and brain of the animals were examined. Eighteen hamsters were inoculated intraperitoneally, and six healthy animals were used as negative controls. The animals were kept in the animal house and checked for clinical signs. Specimens of each organ were examined for the presence of amastigotes. Immunohistochemical technique was performed in all brain specimens and organs negative on the direct examination of parasites. Direct examination of amastigotes was positive in the spleen and liver of all infected animals; 33.3% showed the parasite in the kidneys and lungs, and 16.7% in the heart. Parasitic forms were seen in 83.3% (15/18) of the brain examined. Immunohistochemistry confirmed the results of the direct examination, except in two specimens of lung tissue and in the brain specimens. Other studies are needed to further clarify the effect of the parasite in the central nervous system.

scholarly journals Chronic Subclinical Prion Disease Induced by Low-Dose Inoculum

2002 ◽  
Vol 76 (5) ◽  
pp. 2510-2517 ◽  
Author(s):  
Alana M. Thackray ◽  
Michael A. Klein ◽  
Adriano Aguzzi ◽  
Raymond Bujdoso
Keyword(s):  
Brain Tissue ◽  
Prion Disease ◽  
Low Dose ◽  
Clinical Signs ◽  
Rocky Mountain ◽  
Rapid Onset ◽  
Distinct Pattern ◽  
High Dose ◽  
Terminal Disease ◽  
Subclinical Disease

ABSTRACT We have compared the transmission characteristics of the two mouse-adapted scrapie isolates, ME7 and Rocky Mountain Laboratory (RML), in tga20 mice. These mice express elevated levels of PrP protein compared to wild-type mice and display a relatively short disease incubation period following intracerebral prion inoculation. Terminal prion disease in tga20 mice induced by ME7 or RML was characterized by a distinct pattern of clinical signs and different incubation times. High-dose RML inoculated intracerebrally into tga20 mice induced the most rapid onset of clinical signs, with mice succumbing to terminal disease after only 58 ± 3 days. In contrast, high-dose ME7 gave a mean time to terminal disease of 74 ± 0 days. Histological examination of brain sections from prion-inoculated tga20 mice at terminal disease showed that ME7 gave rise to a more general and extensive pattern of vacuolation than RML. Low-dose inoculum failed to induce terminal disease but did cause preclinical symptoms, including the appearance of reversible clinical signs. Some mice oscillated between showing no clinical signs and early clinical signs for many months but never progressed to terminal disease. Brain tissue from these mice with chronic subclinical prion disease, sacrificed at >200 days postinoculation, contained high levels of infectivity and showed the presence of PrPSc. Parallel analysis of brain tissue from mice with terminal disease showed similar levels of infectivity and detectable PrPSc. These results show that high levels of infectivity and the presence of the abnormal isomer of PrP can be detected in mice with subclinical disease following low-dose prion inoculation.

scholarly journals Borna Disease Virus Accelerates Inflammation and Disease Associated with Transgenic Expression of Interleukin-12 in the Central Nervous System

2002 ◽  
Vol 76 (23) ◽  
pp. 12223-12232 ◽  
Author(s):  
Susanna Freude ◽  
Jürgen Hausmann ◽  
Markus Hofer ◽  
Ngan Pham-Mitchell ◽  
Iain L. Campbell ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Disease Virus ◽  
Biologically Active ◽  
Interleukin 12 ◽  
Wild Type ◽  
Borna Disease Virus ◽  
The Central Nervous System ◽  
Borna Disease

ABSTRACT Targeted expression of biologically active interleukin-12 (IL-12) in astrocytes of the central nervous system (CNS) results in spontaneous neuroimmunological disease of aged mice. Borna disease virus (BDV) can readily multiply in the mouse CNS but does not trigger disease in most strains. Here we show that a large percentage of IL-12 transgenic mice developed severe ataxia within 5 to 10 weeks after infection with BDV. By contrast, no disease developed in mock-infected IL-12 transgenic and wild-type mice until 4 months of age. Neurological symptoms were rare in infected wild-type animals, and if they occurred, these were milder and appeared later. Histological analyses showed that the cerebellum of infected IL-12 transgenic mice, which is the brain region with strongest transgene expression, contained large numbers of CD4+ and CD8+ T cells as well as lower numbers of B cells, whereas other parts of the CNS showed only mild infiltration by lymphocytes. The cerebellum of diseased mice further showed severe astrogliosis, calcifications and signs of neurodegeneration. BDV antigen and nucleic acids were present in lower amounts in the inflamed cerebellum of infected transgenic mice than in the noninflamed cerebellum of infected wild-type littermates, suggesting that IL-12 or IL-12-induced cytokines exhibited antiviral activity. We propose that BDV infection accelerates the frequency by which immune cells such as lymphocytes and NK cells enter the CNS and then respond to IL-12 present in the local milieu causing disease. Our results illustrate that infection of the CNS with a virus that is benign in certain hosts can be harmful in such normally disease-resistant hosts if the tissue is unfavorably preconditioned by proinflammatory cytokines.

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