Matrix metalloproteinase-9 deficiency impairs host defense mechanisms against Streptococcus pneumoniae in a mouse model of bacterial meningitis

Recent reports of human immunodeficiency virus-1 (HIV-1) infection of astrocytes suggest a role for astrocytes in HIV encephalitis. In this study, we infected a human astrocytoma cell line with a pathogenic simian HIV (SHIV_50OLNV) and examined growth patterns and immunomodulatory genes. Approximately 1% of uninfected cells in culture expressed glial fibrillary acid protein (GFAP) whereas 40% of the cells expressed GFAP at 7 days post-inoculation along altered growth patterns. Using targeted cytokine cDNA arrays, we found that SHIV_50OLNV infection resulted in the up-regulation of several genes including metalloproteinase bone morphogenic protein 1 and chemokines monocyte chemoattractant protein 1 and stromal cell derived factor 1. These data suggest that astrocytic activation, altered morphology and up-regulation of immunomodulatory genes in response to SHIV infection may participate in initiation of inflammation and trafficking of infected monocytes/macrophages into the central nervous system, potentiating the development of HIV encephalitis.