Activation of human immunodeficiency virus type 1 by DNA damage in human cells

Abstract

Recent studies indicate that human immunodeficiency virus type 1 (HIV) gene expression can be dramatically enhanced by certain heterologous viral and chemical agents, implicating these as potential reactivating agents of latent virus infection. A common denominator shared by these agents is their ability to cause stress responses in cells. In an effort to determine whether stress responses affect HIV gene expression, we examined the effects of ultraviolet light (UV) and mitomycin C, on HIV gene expression as well as on viral growth and development. We demonstrate that these agents enhance HIV gene expression up to 150-fold. These levels are similar to those obtained by the tat gene product, the HIV trans-activating factor responsible for enhancing viral gene expression. The increase in gene expression after UV irradiation appears to require transcription but not de novo protein synthesis, and correlates with an accumulation of stable mRNA. Most importantly, UV irradiation of human T-cells prior to viral infection significantly shortens the viral growth cycle. Apparently, UV-induced cellular stress is highly conducive for viral replication and growth. We further demonstrate that even direct sunlight can activate HIV gene expression. These results demonstrate that DNA damaging agents, and perhaps other agents which elicit SOS-like stress responses in mammalian cells, can activate HIV expression thereby enhancing viral replication and development.

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

“…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. Heterologous promoter-leader sequence activation is a normal response to various stresses induced by oxygen activated species or by physical agents.…”

Mood‐Enhancing Antidepressant St. John's Wort Inhibits the Activation of Human Immunodeficiency Virus Gene Expression by Ultraviolet Light

“…Nuclear extracts from HIVcat/HeLa cells were prepared from confluent 100-mm dishes as described (14)(15)(16)(17)(18). Briefly, cells from a 100-mm dish were washed and scraped in PBS and collected by slow-speed centrifugation.…”

“…The HIVcat/HeLa (−485/+80) cells, carrying the HIVcat transcriptional units, have been described previously (14)(15)(16)(17). Cells were maintained in DMEM (high glucose) and supplemented with 10% fetal bovine serum (Irvine Scientific from Irvine, CA), penicillin (100 U/ml), and streptomycin (100 µg/ml).…”

“…The same blot was used to probe for equal loading of protein using antibodies to p38 MAP kinase or JNK or p44/42 MAP kinase as described (14,17 ). CAT assays were carried out as described (14)(15)(16)(17).…”

“…Our laboratory has been concerned with the signal transduction pathways induced by UV and ionizing radiation and the transcriptional regulation of HIV-LTR in HeLa cells (14)(15)(16)(17)(18)(19). The gene expression of HIV can be dramatically enhanced by the exposure of HIV-infected or stably transfected HIV reporter gene cell constructs to specific chemical agents, like cytokines or environmental stress, including UV and ionizing radiation, implicating these as potential activating agents of latent virus infection that may influence the course of HIV pathogenesis.…”