Identification of T Cell-Signaling Pathways That Stimulate Latent HIV in Primary Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS 2003-10, Vol.100 (22), p.12955-12960
• Main Authors: Brooks, David G., Arlen, Philip A., Gao, Lianying, Christina M. R. Kitchen, Zack, Jerome A.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Biological Sciences; CD4 Antigens - analysis; Cell cycle; Cell Cycle - immunology; Cell lines; Fetal Tissue Transplantation - immunology; HIV; HIV - physiology; Human immunodeficiency virus; Humans; Immune system; Infections; Liver Transplantation; Medical research; Mice; Mice, SCID; NF-^KB protein; nuclear factor; RNA; Signal Transduction - immunology; Signal Transduction - physiology; T lymphocytes; T-Lymphocytes - immunology; Thymocytes; Thymus Gland - immunology; Transcription factors; Transplantation, Heterologous - immunology; Virus Activation - immunology; Virus Latency - immunology; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2233345100

Eradication of HIV infection depends on the elimination of a small, but stable population of latently infected T cells. After the discontinuation of therapy, activation of latent virus can rekindle infection. To purge this reservoir, it is necessary to define cellular signaling pathways that lead to activation of latent HIV. We used the SCID-hu (Thy/Liv) mouse model of HIV latency to analyze a broad array of T cell-signaling pathways and show in primary, quiescent cells that viral induction depends on the activation of two primary intracellular signaling pathways, protein kinase C or nuclear factor of activated T cells (NF-AT). In contrast, inhibition or activation of other important T cell stimulatory pathways (such as mitogen-activated protein kinase, calcium flux, or histone deacetylation) do not significantly induce virus expression. We found that the activation of NF-κB is critical to viral reactivation; however, all pathways that stimulate NF-κB do not reactivate latent virus. Our studies further show that inhibition of NF-κB does not prevent activation of HIV by NF-AT, indicating that these pathways can function independently to activate the HIV LTR. Thus, we define several molecular pathways that trigger HIV reactivation from latency and provide evidence that latent HIV infection is maintained by the functional lack of particular transcription factors in quiescent cells.