title: Role of cyclophilin A from brains of prion-infected mice in stimulation of cytokine release by microglia and astroglia in vitro.
abstract: Prion diseases or transmissible spongiform encephalopathy diseases are typically characterized by deposition of abnormally folded partially protease-resistant host-derived prion protein (PrPres), which is associated with activated glia and increased release of cytokines. This neuroinflammatory response may play a role in transmissible spongiform encephalopathy pathogenesis. We previously reported that brain homogenates from prion-infected mice induced cytokine protein release in primary astroglial and microglial cell cultures. Here we measured cytokine release by cultured glial cells to determine what factors in infected brain contributed to activation of microglia and astroglia. In assays analyzing IL-12p40 and CCL2 (MCP-1), glial cells were not stimulated in vitro by either PrPres purified from infected mouse brains or prion protein amyloid fibrils produced in vitro. However, significant glial stimulation was induced by clarified scrapie brain homogenates lacking PrPres. This stimulation was greatly reduced both by antibody to cyclophilin A (CyPA), a known mediator of inflammation in peripheral tissues, and by cyclosporine A, a CyPA inhibitor. In biochemical studies, purified truncated CyPA fragments stimulated a pattern of cytokine release by microglia and astroglia similar to that induced by scrapie-infected brain homogenates, whereas purified full-length CyPA was a poor stimulator. This requirement for CyPA truncation was not reported in previous studies of stimulation of peripheral macrophages, endothelial cell cardiomyocytes, and vascular smooth muscle cells. Therefore, truncated CyPA detected in brain following prion infection may have an important role in the activation of brain-derived primary astroglia and microglia in prion disease and perhaps other neurodegenerative or neuroinflammatory diseases.
authors.affiliation: From the Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, National Institutes of Health, Hamilton, Montana 59840.
authors.forename: Déborah
authors.initials: D
authors.lastname: Tribouillard-Tanvier
authors.forename: James A
authors.initials: JA
authors.lastname: Carroll
authors.forename: Roger A
authors.initials: RA
authors.lastname: Moore
authors.forename: James F
authors.initials: JF
authors.lastname: Striebel
authors.forename: Bruce
authors.initials: B
authors.lastname: Chesebro
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001253:Astrocytes / Q000201:enzymology* / Q000473:pathology; D001921:Brain / Q000201:enzymology*; D018932:Chemokine CCL2 / Q000378:metabolism*; D021984:Cyclophilin A / Q000378:metabolism*; D053762:Interleukin-12 Subunit p40 / Q000378:metabolism*; D051379:Mice; D017628:Microglia / Q000201:enzymology* / Q000473:pathology; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D017096:Prion Diseases / Q000201:enzymology*; D011328:Prions / Q000378:metabolism*
chemical_list: D000906:Antibodies; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D053762:Interleukin-12 Subunit p40; D009419:Nerve Tissue Proteins; D011328:Prions; D021984:Cyclophilin A