Involvement of astrocytes in transmissible spongiform encephalopathies: a confocal microscopy study

Abstract

Astroglial proliferation associated with pathological prion protein (PrPsc) deposition is widely described in Transmissible Spongiform Encephalopathies (TSEs). However, little is known of the actual role played by glia in their pathogenesis. The aim of the study has been to determine whether PrPsc is located exclusively in neurons or in both neurons and glial cells present in the central nervous system in a natural Scrapie model. Samples of cerebellum from 25 Scrapie sheep from various flocks were sectioned. Following epitope retrieval with formic acid, proteinase K and heat treatment, primary antibody L42 and primary antibodies against glial fibrillary acidic protein were applied as prion- and astrocytic-specific markers, respectively. For visualization, a suitable mixture of fluorochrome-conjugated secondary antibodies was used. Relevant controls were processed in the same manner. As determined by confocal microscopy, PrPsc deposits co-localized with glial cells in all samples. Our results suggest that these cells can sustain active prion propagation, in agreement with similar findings from other studies of primary cell cultures and inoculated mice. Furthermore, despite ongoing debate regarding whether varied TSE sources show differences in their tropism for different cell lineages in the brains of affected animals, no differences in co-localization results were seen.

Prion Replication Elicits Cytopathic Changes in Differentiated Neurosphere Cultures

“…Thus, it is most likely that prions induced cytopathic changes in astrocyte lineage cells in dNP20 cultures. However, these observations appear to contradict those of previous studies in which astrocytes were observed to be permissive to prion infection in vivo and in vitro (6,(41)(42)(43)(44); nonetheless, there is no evidence to suggest astrocyte loss or degeneration during prion infection in vivo (45) and in slice cultures (46). A possible explanation for this discrepancy is that dNP20 cultures contained immature astrocytes, and these cells may be susceptible to prioninduced cytotoxicity.…”

A comparative study of modified confirmatory techniques and additional immuno-based methods for non-conclusive autolytic Bovine spongiform encephalopathy cases

“…With the purpose of identifying a specific cellular population that seemed to co-localize with PrPsc in several mice, and suggested to be a glial cell due to its morphology and distribution, a confocal microscopy study was carried out following the protocol previously established [28]. …”

Gene and protein patterns of potential prion-related markers in the central nervous system of clinical and preclinical infected sheep

“…In scrapie affected sheep, astrocytosis is one of the most common described histopathological events related with the disease [65]. Thus, glial activation, which is particularly strong in the Mobl and cSc, might partially explain the CAPN6 expression changes.…”