Intranasal tat alters gene expression in the mouse brain.
Intranasal (IN) delivery of HIV-1 Tat in aging mice was investigated as a possible model for HIV-1 infection in the brain. After IN administration, the distribution of [(125)I]-labeled Tat in the brains of Swiss Webster mice was evaluated by autoradiography and gamma counting. [(125)I]-labeled Tat was detected at the highest concentrations in the olfactory bulb, cervical nodes, and trigeminal nerve tract. In another experiment, APPSw transgenic mice were used to model chronic Tat exposure. The mice were treated intranasally with 6 mug Tat (n = 4) or vehicle (n = 4) three times per week for 4 weeks. Total RNA was isolated from the frontal cortex, and differential gene expression analysis was performed using gene microarrays. Gene ontology profiles indicated innate immunity, inflammatory and apoptotic responses. Five genes of interest in the Tat-treated mice that were significantly elevated in the microarrays were validated by RT-PCR. One gene, the Toll-like receptor 9 (Tlr9), has previously been shown to activate signaling cascades leading to innate immunity and enhanced HIV-1 gene expression. A second gene, Fas, plays a key role in neuroinflammation. Two cysteine-rich cytokines associated with chemotaxis were elevated: MCP-1 (Ccl2), which is chemotactic for monocytes, and Ccl17 (TARC), which is chemotactic for lymphocytes. Finally, the gene sestrin was significantly elevated and has been associated with oxidative stress, in particular amyloid beta-induced oxidative stress. This IN Tat model of neuroinflammation may be useful to study HIV-1-induced neurodegeneration.
Department of Laboratory Medicine, Veterans Affairs Medical Center, 4150 Clement St. (113A), San Francisco, CA 94121, USA. lynn.pulliam@ucsf.edu
Lynn
L
Pulliam
Bing
B
Sun
Hans
H
Rempel
Paula M
PM
Martinez
John D
JD
Hoekman
Reshma J
RJ
Rao
William H
WH
Frey
Leah R
LR
Hanson
D000281:Administration, Intranasal; D000818:Animals; D001812:Blood-Brain Barrier / Q000502:physiology; D001921:Brain / Q000378:metabolism* / Q000821:virology; D020869:Gene Expression Profiling; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D015696:Gene Products, tat / Q000008:administration & dosage* / Q000378:metabolism / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology; D007457:Iodine Radioisotopes / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D014018:Tissue Distribution / Q000235:genetics
D015696:Gene Products, tat; D007457:Iodine Radioisotopes