scholarly journals Transforming Growth Factor β Stimulates the Human Immunodeficiency Virus 1 Enhancer and Requires NF-κB Activity

1998 ◽  
Vol 18 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Jian-Ming Li ◽  
Xing Shen ◽  
Patrick Pei-Chih Hu ◽  
Xiao-Fan Wang

ABSTRACT Transforming growth factor β (TGF-β) is the prototype of a large superfamily of signaling molecules involved in the regulation of cell growth and differentiation. In certain patients infected with human immunodeficiency virus type 1 (HIV-1), increased levels of TGF-β promoted the production of virus and also impaired the host immune system. In an effort to understand the signaling events linking TGF-β action and HIV production, we show here that TGF-β can stimulate transcription from the HIV-1 long terminal repeat (LTR) promoter through NF-κB binding sites in both HaCaT and 300.19 pre-B cells. When introduced into a minimal promoter, NF-κB binding sites supported nearly 30-fold activation from the luciferase reporter upon TGF-β treatment. Electrophoretic mobility shift assay indicated that a major factor binding to the NF-κB site is the p50-p65 heterodimeric NF-κB in HaCaT cells. Coexpression of Gal4-p65 chimeric proteins supported TGF-β ligand-dependent gene expression from a luciferase reporter gene driven by Gal4 DNA binding sites. NF-κB activity present in HaCaT cells was not affected by TGF-β treatment as judged by the unchanged DNA binding activity and concentrations of p50 and p65 proteins. Consistently, steady-state levels of IκBα and IκBβ proteins were not changed by TGF-β treatment. Our results demonstrate that TGF-β is able to stimulate transcription from the HIV-1 LTR promoter by activating NF-κB through a mechanism distinct from the classic NF-κB activation mechanism involving the degradation of IκB proteins.

1996 ◽  
Vol 183 (1) ◽  
pp. 99-108 ◽  
Author(s):  
G Zauli ◽  
M Vitale ◽  
D Gibellini ◽  
S Capitani

Human CD34+ hematopoietic progenitor cells, stringently purified from the peripheral blood of 20 normal donors, showed an impaired survival and clonogenic capacity after exposure to either heat-inactivated human immunodeficiency virus (HIV) 1 (strain IIIB) or cross-linked envelope gp120. Cell cycle analysis, performed at different times in serum-free liquid culture, showed an accumulation in G0/G1 in HIV-1- or gp120-treated cells and a progressive increase of cells with subdiploid DNA content, characteristic of apoptosis. In blocking experiments with anti-transforming growth factor (TGF) beta 1 neutralizing serum or TGF-beta 1 oligonucleotides, we demonstrated that the HIV-1- or gp120-mediated suppression of CD34+ cell growth was almost entirely due to an upregulation of endogenous TGF-beta 1 produced by purified hematopoietic progenitors. Moreover, by using a sensitive assay on the CCL64 cell line, increased levels of bioactive TGF-beta 1 were recovered in the culture supernatant of HIV-1/gp120-treated CD34+ cells. Anti-TGF-beta 1 neutralizing serum or TGF-beta 1 oligonucleotides were also effective in inducing a significant increase of the plating efficiency of CD34+ cells, purified from the peripheral blood of three HIV-1-seropositive individuals, suggesting that a similar mechanism may be also operative in vivo. The relevance of these findings to a better understanding of the pathogenesis of HIV-1-related cytopenias is discussed.


1999 ◽  
Vol 73 (2) ◽  
pp. 1331-1340 ◽  
Author(s):  
Koen Verhoef ◽  
Rogier W. Sanders ◽  
Veronique Fontaine ◽  
Shigetaka Kitajima ◽  
Ben Berkhout

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) transcription is regulated by the viral Tat protein and cellular factors, of which the concentration and activity may depend on the cell type. Viral long terminal repeat (LTR) promoter sequences are therefore optimized to suit the specific nuclear environment of the target host cell. In long-term cultures of a Tat-defective, poorly replicating HIV-1 mutant, we selected for a faster-replicating virus with a 1-nucleotide deletion in the upstream copy of two highly conserved NF-κB binding sites. The variant enhancer sequence demonstrated a severe loss of NF-κB binding in protein binding assays. Interestingly, we observed a new binding activity that is specific for the variant NF-κB sequence and is present in the nuclear extract of unstimulated cells that lack NF-κB. These results suggest that inactivation of the NF-κB site coincides with binding of another transcription factor. Fine mapping of the sequence requirements for binding of this factor revealed a core sequence similar to that of Ets binding sites, and supershift assays with antibodies demonstrated the involvement of the GABP transcription factor. Transient transfection experiments with LTR-chloramphenicol acetyltransferase constructs indicated that the variant LTR promoter is specifically inhibited by GABP in the absence of Tat, but this promoter was dramatically more responsive to Tat than the wild-type LTR. Introduction of this GABP site into the LAI virus yielded a specific gain of fitness in SupT1 cells, which contain little NF-κB protein. These results suggest that GABP potentiates Tat-mediated activation of LTR transcription and viral replication in some cell types. Conversion of an NF-κB into a GABP binding site is likely to have occurred also during the worldwide spread of HIV-1, as we noticed the same LTR modification in subtype E isolates from Thailand. This typical LTR promoter configuration may provide these viruses with unique biological properties.


2004 ◽  
Vol 78 (23) ◽  
pp. 13046-13052 ◽  
Author(s):  
Masako Moriuchi ◽  
Hiroyuki Moriuchi

ABSTRACT Breastfeeding plays a substantial role in mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1). Mammary epithelial cells, as well as macrophages and lymphocytes, are thought to serve as sources of the virus in breast milk. Soluble factors in breast milk exert various biological functions, including immune tolerance or immune modulation, and may influence milk-borne infection with HIV-1. In this study we show that transforming growth factor β (TGF-β), a major cytokine in breast milk, inhibited HIV-1 infection of mammary epithelial MCF-7 cells but enhanced that of macrophages. TGF-β downregulated the HIV-1 long terminal repeat (LTR) promoter in MCF-7 cells but upregulated it in macrophages. Stimulation with TGF-β suppressed NF-κB binding to the HIV-1 LTR in MCF-7 cells, at least in part by downregulating induced IκB kinase expression. Cell type-dependent effects of TGF-β on HIV-1 expression may play a role in milk-borne infection with HIV-1.


1991 ◽  
Vol 173 (3) ◽  
pp. 589-597 ◽  
Author(s):  
G Poli ◽  
A L Kinter ◽  
J S Justement ◽  
P Bressler ◽  
J H Kehrl ◽  
...  

The pleiotropic immunoregulatory cytokine transforming growth factor beta (TGF-beta) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected promonocytic cell line U1. TGF-beta significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IL-6). Furthermore, TGF-beta suppressed PMA induction of HIV transcription in U1 cells. In contrast, TGF-beta did not significantly affect the expression of HIV induced by tumor necrosis factor alpha (TNF-alpha). These suppressive effects were not mediated via the induction of interferon alpha (IFN-alpha). TGF-beta also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL-6-stimulated cultures. In contrast, no significant effects of TGF-beta were observed in either a chronically infected T cell line (ACH-2) or in primary T cell blasts infected in vitro. Therefore, TGF-beta may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals.


2004 ◽  
Vol 128 (3) ◽  
pp. 282-291
Author(s):  
Sahnila Enam ◽  
Thersa M. Sweet ◽  
Shohreh Amini ◽  
Kamel Khalili ◽  
Luis Del Valle

Abstract Context.—Progressive multifocal leukoencephalopathy is a fatal demyelinating disease of the central nervous system frequently seen in patients with impaired immune systems, particularly acquired immunodeficiency syndrome. JC virus (JCV), a human neurotropic polyomavirus, is the etiologic infectious agent of this disease. Objective.—The significantly higher incidence of progressive multifocal leukoencephalopathy in patients with acquired immunodeficiency syndrome than in patients with other immunosuppressive conditions suggests that molecular interactions between human immunodeficiency virus 1 and JCV, via the Tat protein, are responsible for the activation of the JCV enhancer/promoter and the development of progressive multifocal leukoencephalopathy. An indirect mechanism through activation of cytokines, such as transforming growth factor β1 and Smads 3 and 4, may also be responsible for the enhancement of JCV gene expression. Design.—Immunohistochemical analysis in progressive multifocal leukoencephalopathy samples and chloramphenicol acetyl transferase assays on cell cultures were performed to corroborate this hypothesis. Results.—The JCV capsid protein VP-1 was found in the nuclei of oligodendrocytes and in the nuclei and cytoplasm of bizarre astrocytes. Human immunodeficiency virus proteins, including p24 and Tat, were detected in the cytoplasm of astrocytes. Tat, but not p24, was detected in oligodendrocytes, suggesting that extracellular Tat accumulates in the nuclei of oligodendrocytes, where JCV gene transcription takes place. High levels of transforming growth factor β1 and Smads 3 and 4 were detected in JCV-infected oligodendrocytes. Results from in vitro studies confirm activation of the JCV early and late promoters by Smads 3 and 4. Conclusions.—These observations support our model, suggesting that the induction of transforming growth factor β1 by human immunodeficiency virus 1 Tat can stimulate its downstream factors, including Smads 3 and 4, which in turn augment transcription of the JCV promoter in glial cells.


1993 ◽  
Vol 13 (8) ◽  
pp. 5057-5069
Author(s):  
V Desai-Yajnik ◽  
H H Samuels

We report that thyroid hormone (T3) receptor (T3R) can activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR). Purified chick T3R-alpha 1 (cT3R-alpha 1) binds as monomers and homodimers to a region in the LTR (nucleotides -104 to -75 [-104/-75]) which contains two tandem NF-kappa B binding sites and to a region (-80/-45) which contains three Sp1 binding sites. In contrast, human retinoic acid receptor alpha (RAR-alpha) and mouse retinoid X receptor beta (RXR-beta) do not bind to these elements. However, RXR-beta binds to these elements as heterodimers with cT3R-alpha 1 and to a lesser extent with RAR-alpha. Gel mobility shift assays also revealed that purified NF-kappa B p50/65 or p50/50 can bind to one but not both NF-kappa B sites simultaneously. Although the binding sites for p50/65, p50/50, and T3R, or Sp1 and T3R, overlap, their binding is mutually exclusive, and with the inclusion of RXR-beta, the major complex is the RXR-beta-cT3R-alpha 1 heterodimer. The NF-kappa B region of the LTR and the NF-kappa B elements from the kappa light chain enhancer both function as T3 response elements (TREs) when linked to a heterologous promoter. The TREs in the HIV-1 NF-kappa B sites appear to be organized as a direct repeat with an 8- or 10-bp gap between the half-sites. Mutations within the NF-kappa B motifs which eliminate binding of cT3R-alpha 1 also abolish stimulation by T3, indicating that cT3R-alpha 1 binding to the Sp1 region does not independently mediate activation by T3. The Sp1 region, however, is converted to a functionally strong TRE by the viral tat factor. These studies indicate that the HIV-1 LTR contains both tat-dependent and tat-independent TREs and reveal the potential for T3R to modulate other genes containing NF-kappa B- and Sp1-like elements. Furthermore, they indicate the importance of other transcription factors in determining whether certain T3R DNA binding sequences can function as an active TRE.


2018 ◽  
Vol 69 (2) ◽  
pp. 295-305 ◽  
Author(s):  
Maia Lesosky ◽  
Molebogeng X Rangaka ◽  
Cara Pienaar ◽  
Anna K Coussens ◽  
Rene Goliath ◽  
...  

Abstract Background The risk of individuals infected with human immunodeficiency virus (HIV)-1 developing tuberculosis (TB) is high, while both prognostic and diagnostic tools remain insensitive. The potential for plasma biomarkers to predict which HIV-1–infected individuals are likely to progress to active disease is unknown. Methods Thirteen analytes were measured from QuantiFERON Gold in-tube (QFT) plasma samples in 421 HIV-1–infected persons recruited within the screening and enrollment phases of a randomized, controlled trial of isoniazid preventive therapy. Blood for QFT was obtained pre-randomization. Individuals were classified into prevalent TB, incident TB, and control groups. Comparisons between groups, supervised learning methods, and weighted correlation network analyses were applied utilizing the unstimulated and background-corrected plasma analyte concentrations. Results Unstimulated samples showed higher analyte concentrations in the prevalent and incident TB groups compared to the control group. The largest differences were seen for C-X-C motif chemokine 10 (CXCL10), interleukin-2 (IL-2), IL-1α, transforming growth factor-α (TGF-α). A predictive model analysis using unstimulated analytes discriminated best between the control and prevalent TB groups (area under the curve [AUC] = 0.9), reasonably well between the incident and prevalent TB groups (AUC > 0.8), and poorly between the control and incident TB groups. Unstimulated IL-2 and IFN-γ were ranked at or near the top for all comparisons, except the comparison between the control vs incident TB groups. Models using background-adjusted values performed poorly. Conclusions Single plasma biomarkers are unlikely to distinguish between disease states in HIV-1 co-infected individuals, and combinations of biomarkers are required. The ability to detect prevalent TB is potentially important, as no blood test hitherto has been suggested as having the utility to detect prevalent TB amongst HIV-1 co-infected persons.


2002 ◽  
Vol 76 (8) ◽  
pp. 3881-3891 ◽  
Author(s):  
Neerja Kaushik ◽  
Amartya Basu ◽  
Paul Palumbo ◽  
Rene L. Myers ◽  
Virendra N. Pandey

ABSTRACT The emergence of drug-resistant variants has posed a significant setback against effective antiviral treatment for human immunodeficiency virus (HIV) infections. The choice of a nonmutable region of the viral genome such as the conserved transactivation response element (TAR element) in the 5′ long terminal repeat (LTR) may potentially be an effective target for drug development. We have earlier demonstrated that a polyamide nucleotide analog (PNA) targeted to the TAR hairpin element, when transfected into cells, can effectively inhibit Tat-mediated transactivation of HIV type 1 (HIV-1) LTR (T. Mayhood et al., Biochemistry 39:11532-11539, 2000). Here we show that this anti-TAR PNA (PNATAR), upon conjugation with a membrane-permeating peptide vector (transportan) retained its affinity for TAR in vitro similar to the unconjugated analog. The conjugate was efficiently internalized into the cells when added to the culture medium. Examination of the functional efficacy of the PNATAR-transportan conjugate in cell culture using luciferase reporter gene constructs resulted in a significant inhibition of Tat-mediated transactivation of HIV-1 LTR. Furthermore, PNATAR-transportan conjugate substantially inhibited HIV-1 production in chronically HIV-1-infected H9 cells. The mechanism of this inhibition appeared to be regulated at the level of transcription. These results demonstrate the efficacy of PNATAR-transportan as a potential anti-HIV agent.


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