Identification of Emerging Macrophage-Tropic HIV-1 R5 Variants in Brain Tissue of AIDS Patients without Severe Neurological Complications

• Published in: Journal of virology Vol. 91; no. 20
• Main Authors: Gonzalez-Perez, Maria Paz, Peters, Paul J, O'Connell, Olivia, Silva, Nilsa, Harbison, Carole, Cummings Macri, Sheila, Kaliyaperumal, Saravanan, Luzuriaga, Katherine, Clapham, Paul R
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 15-10-2017
• Subjects: Acquired Immunodeficiency Syndrome - complications; Acquired Immunodeficiency Syndrome - drug therapy; Acquired Immunodeficiency Syndrome - virology; Blood-Brain Barrier; Brain - virology; Genes, env; HIV-1 - genetics; HIV-1 - isolation & purification; HIV-1 - physiology; Humans; Macrophages - virology; Viral Tropism; Virion - genetics; Virus Replication; Virus-Cell Interactions; human immunodeficiency virus; tropism; neurotropism; macrophage tropism; brain; envelope glycoprotein
• DOI: 10.1128/JVI.00755-17
• EISSN: 1098-5514
• ISSN: 0022-538X

Untreated HIV-positive (HIV-1
) individuals frequently suffer from HIV-associated neurocognitive disorders (HAND), with about 30% of AIDS patients suffering severe HIV-associated dementias (HADs). Antiretroviral therapy has greatly reduced the incidence of HAND and HAD. However, there is a continuing problem of milder neurocognitive impairments in treated HIV
patients that may be increasing with long-term therapy. In the present study, we investigated whether envelope (
) genes could be amplified from proviral DNA or RNA derived from brain tissue of 12 individuals with normal neurology or minor neurological conditions (N/MC individuals). The tropism and characteristics of the brain-derived Envs were then investigated and compared to those of Envs derived from immune tissue. We showed that (i) macrophage-tropic R5 Envs could be detected in the brain tissue of 4/12 N/MC individuals, (ii) macrophage-tropic Envs in brain tissue formed compartmentalized clusters distinct from non-macrophage-tropic (non-mac-tropic) Envs recovered from the spleen or brain, (iii) the evidence was consistent with active viral expression by macrophage-tropic variants in the brain tissue of some individuals, and (iv) Envs from immune tissue of the N/MC individuals were nearly all tightly non-mac-tropic, contrasting with previous data for neuro-AIDS patients where immune tissue Envs mediated a range of macrophage infectivities, from background levels to modest infection, with a small number of Envs from some patients mediating high macrophage infection levels. In summary, the data presented here show that compartmentalized and active macrophage-tropic HIV-1 variants are present in the brain tissue of individuals before neurological disease becomes overt or serious.
The detection of highly compartmentalized macrophage-tropic R5 Envs in the brain tissue of HIV patients without serious neurological disease is consistent with their emergence from a viral population already established there, perhaps from early disease. The detection of active macrophage-tropic virus expression, and probably replication, indicates that antiretroviral drugs with optimal penetration through the blood-brain barrier should be considered even for patients without neurological disease (neuro-disease). Finally, our data are consistent with the brain forming a sanctuary site for latent virus and low-level viral replication in the absence of neuro-disease.