Activation of Human Immunodeficiency Virus Type 1 by Oxidative Stress

Abstract

An important aspect of the infection by the human immunodeficiency virus (HIV-1) type 1 is its clinical latency, suggesting that the virus itself or the provirus may remain latent for extended periods of time after primary infection. Certain heterologous viral proteins or chemical and physical agents are able to reactivate latent virus. Since a common denominator shared by these agents is the ability to cause stress response in cells, we have examined the effects of oxidative stress mediated by hydrogen peroxide (H2O2) on HIV-1 latently infected promonocytic cell line termed U1. After exposure to H2O2 in concentrations ranging from 0.1 to 2 mM, the viability of the U1 cells decreased during 24 h before recovery. At 24 h post stress, the U1 cells began to express virus as assessed by elevated reverse transcriptase activities in culture supernatants. Immunofluorescence carried out on stressed U1 cells using anti-HIV-1 polyclonal antibodies showed that H2O2 leads to HIV-1 gene expression activation, but not to a release of viral particles from damaged cells. Additionally, using a HeLa cell line containing integrated the bacterial chloramphenicol acetyl transferase (CAT) gene under the control of the HIV-1 long terminal repeat (LTR), we have shown that oxidative stress mediated by H2O2 allows transactivation of the viral LTR revealed by intracellular CAT activity. A stimulation factor of around 4 of CAT activity can be reached when these cells are treated with 0.5 mM H2O2.(ABSTRACT TRUNCATED AT 250 WORDS)

HIV-1 promoter activation following an oxidative stress mediated by singlet oxygen

“…In our work, we have unambiguously shown that singlet oxygen generated through RB, either free in solution or bound to beads, can lead to the induction of heterologous genes controlled by a viral promoter-leader sequence such as that involved in HIV-1 LTR. This transactivation of HIV-1 LTR has also been reported following oxidative stress mediated by hydrogen peroxide on epithelial cells [20] and human T cells [25]. In addition, UVmediated stress on epithelial cells [38] and transgenic mice [39] and psoralen adducts induced by 8-methoxypsoralen plus UVA in the skin of transgenic mice [40] can promote the transcriptional activation of a gene controlled by HIV-1 LTR.…”

“…This situation of oxidative stress is especially relevant to in vivo situations where HIV-1 latently infected T cells may be proximal to activated phagocytes during inflammatory reactions. Previous work from our laboratory has shown that oxidative stress produced by hydrogen peroxide can induce the reactivation of latent HIV-1 [20]. This virus predominantly infects T-helper cells, macrophages and monocytes [21].…”

“…Factors triggering HIV-1 reactivation are those, such as cytokines, which achieve the increase in regulatory factors over a certain critical level to promote viral gene expression. Because inflammatory cytokines [24] and hydrogen peroxide [20,25] have been shown to promote HIV-1 reactivation, we attempted to determine whether or not 1 O 2 is capable of mediating HIV-1 promoter activation and HIV-1 reactivation.…”

Dithiocarbamates as potent inhibitors of nuclear factor kappa B activation in intact cells.

“…[20][21][22][23][24][25][26][27][28][29][30] mM N-acetyl-I.-cysteine (NAC) (8,7) or 0.5 mM t-cysteine (9) could block NF-KB induction upon PMA or TNF treatment of cells. The chemical basis for the inhibiting effect of the compounds seemed to lie in an oxygen radical-scavenging effect of the thiol groups.…”

“…The molecular basis for this activity of DDTC is unknown, but thought to be related to the previously described radicalscavenging, antioxidative properties ofdithiocarbamates (22)(23)(24). The recent observation that exposure to oxidative stress of cell cultures latently infected with HIV-1 induces activation of the provirus and viral replication (7,25,26) would explain the antiviral effect of antioxidants. Also consistent with an important role of oxidative stress in the progression of AIDS are the observations that HIV-infected patients have decreased levels of plasma cysteine (27, and reviewed in reference 28), and that antioxidants, such as vitamin C (29), NAC (30), and glutathione (and esters) (31), suppress HIV-1 replication.…”