Expression of inflammatory cytokines and inducible nitric oxide synthase in brains of SIV-infected rhesus monkeys: applications to HIV-induced central nervous system disease.
BACKGROUND
Human immunodeficiency virus type 1 (HIV-1) infection of the central nervous system (CNS) can lead to severe impairments in cognition, behavior, and motor skills. The mechanism(s) by which HIV-1 induces CNS disease are not well understood. Recent evidence suggests that expression of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) may contribute to HIV-1-induced neurologic disease. We sought to determine if these factors were present in the CNS of rhesus monkeys with simian immunodeficiency virus (SIV)-induced CNS disease.


METHODS
Total NO production in cerebral spinal fluid (CSF) from infected monkeys was determined by measuring nitrite (NO2-) and nitrate (NO3-) (stable NO degradation products) utilizing Greiss reagents. In situ hybridization revealed iNOS, interferon-gamma (IFNgamma), and interleukin 1 beta (IL-1 beta) mRNA in the brains of SIV-infected monkeys. Microglia were isolated from animals infected with SIV. Following stimulation with LPS, induction of iNOS mRNA in isolated microglia was analyzed by reverse transcriptase-polymerase chain reaction.


RESULTS
Serial CSF samples from an SIV-infected monkey reveal increased levels of NO2-/NO3-. In situ hybridization demonstrated iNOS, IFN gamma, and IL-1 beta mRNAs in post-mortem brain tissue of SIV-infected monkeys. Furthermore, stimulated microglia from an SIV-infected monkey could produce iNOS mRNA.


CONCLUSIONS
The presence of iNOS in the brain and NO2-/NO3- in the CSF indicates that NO is produced in the CNS of SIV-infected monkeys. The data suggest that iNOS and NO may be contributing to SIV-induced CNS disease.
Department of Neuropharmacology, Scripps Research Institute, La Jolla, California 92037, USA.
T E
TE
Lane
M J
MJ
Buchmeier
D D
DD
Watry
H S
HS
Fox
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology / Q000821:virology; D002490:Central Nervous System / Q000378:metabolism / Q000821:virology; D003001:Cloning, Molecular; D005786:Gene Expression Regulation / Q000235:genetics; D006678:HIV / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods; D007371:Interferon-gamma / Q000032:analysis; D007375:Interleukin-1 / Q000032:analysis; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000378:metabolism; D008969:Molecular Sequence Data; D009566:Nitrates / Q000134:cerebrospinal fluid / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D009573:Nitrites / Q000134:cerebrospinal fluid / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D016415:Sequence Alignment; D017421:Sequence Analysis; D015302:Simian Immunodeficiency Virus / Q000378:metabolism*
D007375:Interleukin-1; D008070:Lipopolysaccharides; D009566:Nitrates; D009573:Nitrites; D012333:RNA, Messenger; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase