Human cytomegalovirus replication and modulation of apoptosis in astrocytes.
OBJECTIVE
To characterize replication patterns and cytopathic effects during human cytomegalovirus (HCMV) infection of brain cells.


METHODS
Primary human mixed glial/neuronal cells, as well as purified microglial, astroglial, and enriched neuronal cell cultures, were infected with HCMV strains AD169 and RC256 to determine the ability of the different brain cell types to support viral replication.


RESULTS
Mixed glial/neuronal cell cultures were fully permissive for viral replication. Based on previous studies, we hypothesized that human microglial cells would preferentially support productive HCMV replication. However, HCMV did not replicate or display genomic expression in microglial cells. In contrast, primary astrocytes were fully permissive and displayed HCMV-induced cytopathic effects resulting in cell death. In highly enriched neuronal cultures, productive infection and viral expression occurred only in scattered astrocytes. Early in the infection, apoptotic plasma membrane changes were induced in astrocytes. However, nuclear fragmentation was not apparent until later during the course of infection.


CONCLUSIONS
These results suggest that HCMV possesses astrocytotropic properties that confer preferential expression and cytopathic replication in astrocytes over microglia or neuronal cells. Apoptotic cell death, which is a result of HCMV infection, appears to be delayed until peak viral replication has occurred.
Lokensgard
J R
JR
Institute for Brain and Immune Disorders, Minneapolis Medical Research Foundation, Minnesota 55404, USA. jlokensg@biosci.cbs.umn.edu
Cheeran
M C
MC
Gekker
G
G
Hu
S
S
Chao
C C
CC
Peterson
P K
PK
D000956:Antigens, Viral / Q000276:immunology / Q000378:metabolism; D017209:Apoptosis; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism / Q000821:virology*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D018920:Coculture Techniques; D003587:Cytomegalovirus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D003588:Cytopathogenic Effect, Viral; D053938:DNA Fragmentation; D015967:Gene Expression Regulation, Viral; D006801:Humans; D017874:Immediate-Early Proteins / Q000276:immunology / Q000378:metabolism; D007158:Immunologic Techniques; D017628:Microglia / Q000166:cytology / Q000378:metabolism / Q000821:virology; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000821:virology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014779:Virus Replication
D000956:Antigens, Viral; D017874:Immediate-Early Proteins; D016159:Tumor Suppressor Protein p53