myelin-basic-protein and Cytomegalovirus-Infections

Cytomegalovirus (CMV) is the most common opportunistic viral pathogen associated with HIV/AIDS or immunosuppressive therapy. Systemic pathology may be caused either through direct virus-mediated infection or by indirect mechanisms such as 'by-stander' apoptosis. CMV infection of the central nervous system (CNS) occurs late in disease progression and understanding of pathology in the brain is fundamental for selection of appropriate therapies.. Using a model of disseminated neurotropic CMV disease, these experiments are designed to identify cellular predilection of murine CMV (MCMV) within mature brain and to determine, if CMV induces apoptosis within CNS cells.. Adult immunodeficient (SCID) and normal BALB/c mice were infected via the tail vein with 4.5 x 10(5)pfu recombinant MCMV expressing a green fluorescent protein reporter. Animals were perfused at various time periods from 3 to 35 days post inoculation and tissues were stained for MCMV, GFAP, NEU-N, MBP, TUNEL, and caspase-3.. CMV infection within brain was observed in multiple, independent foci affecting several different cell types, including neurons, glial cells, meninges, ependymal cells, and cerebral vessels. Cellular changes included nuclear karyopyknosis and karyorrhexis, and associated meningitis, choroiditis, encephalitis, vasculitis, and necrosis. TUNEL and caspase-3 staining of brain-demonstrated apoptosis of nearby 'by-stander' meningial, glial, and neuronal cells, but only in immunodeficient mice lacking T- and B-lymphocytes. Generally, only large CMV infection foci were associated with apoptosis of non-infected adjacent cells.. These results indicate that MCMV may cause both direct and indirect pathology to brain and that T-cell independent apoptosis of surrounding cells of the CNS may be an important mechanism of disease in the pathogenesis of neurotropic CMV.

Topics: Animals; Apoptosis; Brain; Brain Diseases; Caspase 3; Caspases; Cytomegalovirus; Cytomegalovirus Infections; Female; Glial Fibrillary Acidic Protein; Immunocompromised Host; In Situ Nick-End Labeling; Mice; Mice, Inbred BALB C; Mice, SCID; Myelin Basic Protein; Severe Combined Immunodeficiency; T-Lymphocytes

Cytomegalovirus (CMV) is the most significant infectious cause of congenital infection and fatal diseases in immunocompromised patients. We have previously described a transgenic mouse model of the murine CMV (MCMV) immediate-early (IE) gene promoter fused with the lacZ reporter gene (MCMV-IE-pro1) for the analysis of spatiotemporal changes of the promoter activity during brain development. Since expression of the IE genes play a pivotal role in latency and reactivation, we transplanted the transgene-expressing neural stem cells (NSCs) into neonatal mouse brains after labeling with bromodeoxyuridine (BrdU). The activation of MCMV-IE pro1 was detected in the subventricular zone (SVZ) soon after transplantation, and the number of MCMV IE pro1-activated cells was decreased as the development proceeded. Cells that were MCMV IE pro1-activated and glial fibrillary acidic protein positive, but not stained with BrdU, were found in the cortex 4 weeks after transplantation, while BrdU-positive but not MCMV IE pro1-activated cells still existed in the SVZ. MCMV IE promoter activity tended to be easily detected in the cortex after allogenic transplantation in BALB/c mouse. These results suggest that the SVZ is the most susceptible site for activation of the MCMV IE promoter in neonatal mice in the early period after transplantation and that the cerebral cortex is also susceptible to the activation in the late period after transplantation. It may be important to avoid the use of NSCs latently infected with CMV as donor cells.

Topics: Animals; Animals, Newborn; Cells, Cultured; Cerebral Cortex; Cytomegalovirus Infections; Embryo, Mammalian; Galactosides; Glial Fibrillary Acidic Protein; Immunohistochemistry; In Situ Hybridization; Indoles; Lac Operon; Mice; Mice, Transgenic; Muromegalovirus; Myelin Basic Protein; Neurons; Phosphopyruvate Hydratase; Promoter Regions, Genetic; Stem Cell Transplantation; Stem Cells; Time Factors