Late virus replication events in microglia are required for neurovirulent retrovirus-induced spongiform neurodegeneration: evidence from neural progenitor-derived chimeric mouse brains
| Autor: | Evan Y. Snyder, Louis Qualtiere, William P. Lynch, John L. Portis, Andarlene H. Sharpe |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Central Nervous System
Molecular Sequence Data Retroviridae Proteins Oncogenic Immunology Gene Expression Gene Products gag Virus Replication Microbiology Virus Cell Line Prion Diseases Mice Retrovirus Viral Envelope Proteins Virology medicine Animals Progenitor cell Base Sequence Virulence Microglia biology Neurodegeneration Brain medicine.disease biology.organism_classification Neural stem cell Transplantation Retroviridae medicine.anatomical_structure Viral replication Insect Science DNA Viral Research Article |
| Zdroj: | Journal of Virology. 70:8896-8907 |
| ISSN: | 1098-5514 0022-538X |
| DOI: | 10.1128/jvi.70.12.8896-8907.1996 |
| Popis: | CasBrE is a neurovirulent murine retrovirus which induces a spongiform myeloencephalopathy in susceptible mice. Genetic mapping studies have indicated that sequences responsible for neurovirulence reside within the env gene. To address the question of direct envelope protein neuroxicity in the central nervous system (CNS), we have generated chimeric mice expressing the CasBrE envelope protein in cells of neuroectodermal origin. Specifically, the multipotent neural progenitor cell line C17.2 was engineered to express the CasBrE env gene as either gp70/p15E (CasE) or gp70 alone (CasES). CasE expression in these cells resulted in complete (>10(5)) interference of superinfection with Friend murine leukemia virus clone FB29, whereas CasES expression resulted in a 1.8-log-unit decrease in FB29 titer. Introduction of these envelope-expressing C17.2 cells into the brains of highly susceptible IRW mice resulted in significant engraftment as integral cytoarchitecturally correct components of the CNS. Despite high-level envelope protein expression from the engrafted cells, no evidence of spongiform neurodegeneration was observed. To examine whether early virus replication events were necessary for pathogenesis, C17.2 cells expressing whole virus were transplanted into mice in which virus replication in the host was specifically restricted by Fv-1 to preintegration events. Again, significant C17.2 cell engraftment and infectious virus expression failed to precipitate spongiform lesions. In contrast, transplantation of virus-expressing C17.2 progenitor cells in the absence of the Fv-1 restriction resulted in extensive spongiform neurodegeneration by 2 weeks postengraftment. Cytological examination indicated that infection had spread beyond the engrafted cells, and in particular to host microglia. Spongiform neuropathology in these animals was directly correlated with CasBrE env expression in microglia rather than expression from neural progenitor cells. These results suggest that the envelope protein of CasBrE is not itself neurotoxic but that virus infectious events beyond binding and fusion in microglia are necessary for the induction of CNS disease. |
| Databáze: | OpenAIRE |
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