UV activation of human immunodeficiency virus gene expression in transgenic mice

Activation of HIV in human skin by ultraviolet B radiation and its inhibition by NFkappaB blocking agents

To determine whether ultraviolet B (UVB) irradiation leads to activation of HIV in human skin, we conducted prospective and controlled studies in two academic medical centers in Texas from July 1995 to April 1999. HIV-positive patients with UV-treatable skin diseases were enrolled at each center, 18 subjects at one and 16 at the other. In one center, specimens from lesional and nonlesional skin biopsies were taken before and after sham- or UVB-irradiation administered in vivo or in vitro. In the other center, UVB phototherapy was administered three times weekly and specimens from skin biopsies were taken before and after 2 weeks (six treatments). Cutaneous HIV load was assessed using reverse transcriptase-polymerase chain reaction and reverse transcriptase-polymerase chain reaction in situ hybridization. UVB irradiation led to a 6-10-fold increase in the number of HIV in skin. To ascertain a role for nuclear factor kappa B (NFkappaB) in UVB-inducible HIV activation, two types of blockers, NFkappaB oligonucleotide decoy and sodium salicylate, were tested; each inhibited UVB-inducible HIV activation in skin partially. We conclude that UVB irradiation leads to increased numbers of HIV in human skin via processes that include release of cytoplasmic NFkappaB.

Lipopolysaccharide-induced HIV-1 expression in transgenic mice is mediated by tumor necrosis factor-alpha and interleukin-1, but not by interferon-gamma nor interleukin-6

BACKGROUND

As serum HIV-1 load correlates well with the prognosis of the disease, it is suggested that the viral load is one of the major determinants of the disease progression of AIDS. Accordingly, HIV-1 activation mechanisms were extensively studied in vitro, and involvement of cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6 and interferon (IFN)-gamma has been suggested in this process. However, so far the roles of these cytokines in the HIV-1 expression in vivo have not been well elucidated because of the lack of appropriate animal disease models.

OBJECTIVE

To elucidate the roles of cytokines in HIV-1 activation in vivo.

DESIGN AND METHODS

Transgenic mice carrying a defective HIV-1 genome were used as a model for HIV-1 carriers. In order to examine the possible involvement of cytokines in HIV-1 expression, TNF-alpha-, IL-1-, IL-6- and IFN-gamma-deficient HIV-1 transgenic mice, were produced and HIV-1 expression was analyzed after activation with bacterial lipopolysaccharides (LPS).

RESULTS

HIV-1 expression in the transgenic mouse spleen was activated 10- to 20-fold by LPS, and the serum p24 Gag protein levels reached 400 pg/ml, which is nearly equal to the levels that occur in AIDS patients. However, this augmentation was suppressed by 60% in TNF-alpha-deficient mice and by 40% in IL-1alpha/beta-deficient mice. In contrast, no suppression was observed in either IL-6-, IFN-gamma-, IL-1alpha, or IL-1beta-deficient mice.

CONCLUSIONS

Results suggest that TNF-alpha and IL-1 play important roles in HIV-1 gene activation and selective suppression of these cytokines could improve clinical prognosis and potentially slow progression of the disease.

HIV and AIDS in inpatient dermatology. Approach to the consultation

In the inpatient setting, the dermatologic consultant is called on to address the whole spectrum of cutaneous disease seen in HIV/AIDS patients, with severity varying from severe life-threatening to less serious conditions that dramatically affect quality of life. Rather than reviewing a "laundry list" of conditions associated with HIV/AIDS or the most severe conditions, this article aims to demonstrate a systematic approach to inpatient dermatology consultation in HIV/AIDS patients and to briefly review several common and interesting topics frequently addressed in the inpatient setting (e.g., medications issues, and phototherapy in HIV-infected patients).

Transcriptional activation of endogenous retroviral sequences in human epidermal keratinocytes by UVB irradiation

Ultraviolet radiation is a pathogenic factor in various diseases, e. g., autoimmune disorders such as lupus erythematosus. On the other hand, endogenous retroviruses are discussed as etiologic agents in lupus erythematosus. Therefore, we investigated the influence of ultraviolet irradiation on expression of human endogenous retroviral sequences and human endogenous retroviral sequence promoter-driven transcription of cellular genes using human epidermal keratinocytes as a model system. First, conserved sequences of endogenous retroviral pol genes were amplified from cellular mRNA by reverse transcriptase polymerase chain reaction with degenerate oligonucleotide primers. Polymerase chain reaction products were hybridized in a reverse dot blot hybridization assay to a representative number of distinct cloned human endogenous retroviral pol fragments. Using this method, we could show that irradiation with 30 mJ per cm2 ultraviolet B activates transcription of various endogenous retroviral pol sequences in primary epidermal keratinocytes as well as in a spontaneously immortalized keratinocyte cell line (HaCaT). Interestingly, some of these sequences were found to be closely related to pol sequences of human endogenous retroviral sequences which have been shown to be expressed in autoimmune patients. Analysis of human endogenous retroviral pol expression in vivo using skin biopsies of lupus erythematosus patients revealed similar activation patterns. In a second approach, ultraviolet B- induced chimeric transcripts were isolated which are initiated by human endogenous retroviral promoters and proceed into cellular sequences using a newly established modified differential display polymerase chain reaction technique. The activation of human endogenous retroviral sequence transcription by ultraviolet B may contribute to the pathogenesis of lupus erythematosus, where inappropriate antigenic presentation of ultraviolet B-induced viral and cellular proteins could stimulate autoantibody production.

Pathogenesis of non-AIDS-defining cancers: a review

As the AIDS epidemic advances, the number of HIV-infected subjects developing AIDS-related neoplasms is rapidly increasing, and the spectrum of malignancies encountered is expanding. Several non-AIDS-defining cancers are being reported at an increasing incidence in HIV-infected individuals, including anal, skin, oral mucosa, head and neck and lung carcinomas, testicular tumors, and pediatric soft-tissue sarcoma. There appears to be an emerging role for various concurrent viral infections in the HIV-infected host that are likely implicated in the pathogenesis of some nondefining-AIDS neoplasms. Our recent findings in HIV-associated lung cancers and in the precursor lesions of cervical carcinoma suggest that wide-spread genomic instability, as manifested by the development of increased numbers of microsatellite alterations (MAs), may occur frequently in HIV-associated tumors and they may play an important role in the pathogenesis of those neoplasms. Although the mechanism underlying the development of increased MAs is unknown, it may play a crucial role in the development of many HIV-associated tumors. It will be important to track the epidemiological and biological features of non-AIDS-defining cancers in HIV-infected patients, and compare them to those tumors in the general population. It is likely that further clues about malignant transformation and oncogenesis unraveled in the HIV setting will have broad clinical implications.

HIV, UV and immunosuppression

Cutaneous diseases are common manifestations of infection with human immunodeficiency virus (HIV). Phototherapy with ultraviolet B (UVB) and photochemotherapy with 8-methoxypsoralen plus UVA (PUVA) have been used successfully to treat several of these skin conditions, including psoriasis, folliculitis, pruritus, and eczema. However, in view of the known immunosuppressive effects of UV radiation, concerns have been raised about potential adverse effects of UV on persons infected with HIV. In the following report, we review the effects of UV in HIV-infected cell lines in vitro, in animal models, as well as in human studies. Based on currently available data, UV radiation, as used in phototherapy and photochemotherapy, appears to have no adverse effects in HIV-infected individuals.

Viral spread within ageing bacterial populations

The viral spread within isolated host populations has been studied throughout the growth of P22-infected Salmonella cell colonies. By using an integration mutant of this bacteriophage, horizontal and vertical transmission have been analyzed independently. The data obtained show that both strategies are not simultaneous but consecutive during the colony development. Lytic cycles are tightly repressed during the exponential cell growth but stimulated in independent colonies with remarkable synchrony when the cell division rate decreases. The coincidence of the viral outburst and the decay of bacterial replicative fitness is a new example of the extreme viral competence in exploiting the host cells as dissemination vehicles for viral genomes.

Solar ultraviolet radiation exposure does not appear to exacerbate HIV infection in homosexual men. The Multicenter AIDS Cohort Study

OBJECTIVE

To determine the effect of sun exposure on HIV progression.

DESIGN

Cross-sectional survey nested within a longitudinal cohort study.

SETTING

The Multicenter AIDS Cohort Study.

PARTICIPANTS

A total of 1155 white HIV-seronegative and 496 white HIV-seropositive homosexual men, of whom 142 seroconverted during the study.

MAIN OUTCOME MEASURES

T-helper lymphocyte decline and AIDS.

RESULTS

No positive correlation was found between the development of AIDS or loss of T-helper lymphocytes and (i) phenotypic characteristics associated with enhanced ultraviolet radiation (UVR) sensitivity (hair or eye color, skin type), or (ii) reported UVR exposure (sun lamp/tanning bed use, frequency of beach vacations, sunscreen use), or (iii) composite score of UVR sensitivity and exposure history. The composite scores and individual measures of risk were not correlated with rate of T-helper lymphocyte decline (slope) based upon rank correlation (correlation coefficient, 0.04; P = 0.32). In fact, individuals purposefully seeking the sun had slower T-helper lymphocyte declines. Sensitivity to UVR was also not significantly associated with AIDS [odds ratio (OR), 1.11 per unit of higher composite score; 95% confidence interval (CI), 0.66-1.88; P = 0.63]. Among individuals who were HIV-infected at baseline, those who have been purposely seeking sun exposure were less likely to have AIDS (OR, 0.67; 95% CI, 0.39-1.11; P = 0.12).

CONCLUSIONS

These data suggest that phenotypic characteristics of high UVR sensitivity and exposure are not highly correlated with decline in T-helper lymphocyte count or with progression to AIDS.

Transgenic and null mutant animals for psychosomatic research

OBJECTIVE

Progress in the use of genetically altered animals for psychosomatic research is reviewed.

METHOD

Analysis of the strengths and weaknesses of these models, particularly from a developmental and behavioral prospective is used to assess the validity of these models.

RESULTS

Genetically altered animals can be used to create models of the estimated 5000 human diseases in which genetic predispositions play a role, as well as models for diseases that do not involve gene defects, such as human immunodeficiency virus (HIV) infection. In addition, these models have already contributed immensely to our understanding of basic biology and the biology of behavior. Replication of human gene defects in mice has provided direct models of human disease, but there are various factors that sometimes prevent the gene defect from producing the human disease in mice. However, even in this case, the models can contribute to understanding the basic biology of the disease.

CONCLUSIONS

While genetically altered animals have revolutionized the understanding of single gene disorders, their promise has not yet been fulfilled for multigenic behavioral disorders. Newer techniques to allow control of the tissue and stage of development at which a gene is expressed are likely to enhance the usefulness of these models for psychosomatic research. New models of disease for testing psychological impacts on illness and specific ways altering neurotransmitter function will be discovered. While these models will be extremely useful to psychosomatic medicine, the nature of this discipline of necessity involves emphasis on individual experience, and thus will never be amenable to exclusively genetic analysis.

Is phototherapy safe for HIV-infected individuals?

Patients infected with human immunodeficiency virus (HIV) have a high prevalence of UV radiation-responsive skin diseases including psoriasis, pruritus, eosinophilic folliculitis and eczemas. On the other hand, UV has been shown to suppress T cell-mediated immune responses and to induce activation and replication of HIV. These developments have prompted clinicians and investigators to question whether phototherapy is safe for HIV-infected individuals. We have reviewed these issues and hereby provide a summary and critique of relevant laboratory and clinical evidence.

Influence of hydrogen peroxide on the in vitro infectivity of human immunodeficiency virus

The object of this study was to investigate the influence of reactive oxygen intermediates (ROI), such as H2O2, on HIV-1 infection of cell cultures. The CD4+ HeLa human epithelial carcinoma cell line clone pBKTRLac was infected with HIV-1MN that had been treated with 0.01-5mM H2O2. Virus infectivity was detected by 3 methods: (a) using transactivation of LTR-linked beta-Galactosidase, (b) viral core p24 antigen enzyme-linked immunoasorbent assay (ELISA), and (c) reverse transcriptase activity assay. Treatment of HIV-1MN cell free virus particles with 0.01 mM H2O2 resulted in a significant increase in virus infection. This effect declined with increasing H2O2 concentrations from 0.05 to 0.1 mM. Further increases in H2O2 concentration up to 5 mM resulted in significant suppression in virus infection. These observations indicate that H2O2 may play a role in affecting the course of HIV infection.

Transgenic models of human immunodeficiency virus type-1

Transgenic models have provided significant insights into HIV-1 pathogenesis, particularly with regards to Kaposi's sarcoma. HIV-associated nephropathy, the tissue-restricted expression of CNS strains of HIV-1, and the function of Nef in vivo. Both multigenic and single gene constructs have contributed to our understanding of HIV-1-induced diseases. While failing to provide models suitable for vaccine development, these transgenic models have provided great insight into HIV pathogenesis and may yet provide a means for the development and testing of molecular based therapies for AIDS.

Human immunodeficiency virus and the skin: selected controversies

Acquired immunodeficiency syndrome was first recognized as a new disease in 1981 because of the unusual association of Kaposi's sarcoma and Pneumocystis carinii pneumonia in young men. The skin remains one of the most important clinical markers for acquired immunodeficiency syndrome, now recognized as the end stage of infection with the human immunodeficiency virus (HIV). Indeed, an urticarial viral exanthem appearing during seroconversion may allow early identification of newly infected individuals who might benefit from administration of antiviral therapy during plasma viremia. The "asymptomatic HIV infection" is often accompanied by multiple skin complaints, which commonly include xerosis, pruritus, psoriasis/seborrheic dermatitis, and pruritic papular eruptions, the cause of which remains controversial. Psoriasis and Kaposi's sarcoma lesions share features including angiogenesis, dermal dendrocytes infected with HIV, and epidermal hyperproliferation, and are manifested by mice transgenic for HIV provirus or Tat-ltr. Changes in the immune system including T-cell function, antigen response, and shifting cytokine expression as well as a propensity for autoimmune reactions must underlie the skin immunodysfunction occurring in the setting of HIV infection. One of the most unsettling controversies suggested by in vitro data is that ultraviolet light, an effective therapy for HIV-related skin disorders, may actually activate the virus.

Ultraviolet irradiation and cytokines as regulators of HIV latency and expression

The ability of the human immunodeficiency virus (HIV) to persist and replicate in human CD4+ T lymphocytes and mononuclear phagocytes is under the control of both virally encoded proteins and a variety of host-related factors. Ultraviolet (UV) light has been shown to induce transcription and expression of HIV. Both DNA damage and repair and DNA damage/repair-independent pathways caused by UV irradiation lead to expression of proviral HIV genomes via activation of the cellular transcription factor NF-kappa B. Transgenic mice that contain either long terminal repeat (LTR)-reporter genes or HIV genomes, either full length or deleted in the gag-pol region, express RNA and proteins at the epidermal level, particularly after UV irradiation. Furthermore, UV-triggered release of soluble factors capable of inducing expression of HIV in non-irradiated cells has been observed. Among other host factors, the functional network of pro-inflammatory and immunoregulatory cytokines has been demonstrated to act as a potent regulator of HIV replication, at least in different in vitro systems of infection.

Reassessment of the differential effects of ultraviolet and ionizing radiation on HIV promoter: the use of cell survival as the basis for comparisons

Effects of different radiation treatments on the human immunodeficiency virus-1 (HIV) promoter were reassessed for exposures comparable to those encountered in clinical or cosmetic practice, using survival of the host cell as a basis for comparisons. The exposures were performed with two ultraviolet radiation sources commonly used as medical or cosmetic devices (UVASUN 2000 and FS20 lamps), a germicidal (G15T8) lamp and an X-ray machine. The UVC component of the FS20 lamp was filtered out. The emission spectra of the lamps were determined. The characteristics of these sources allowed us to discriminate among effects of UVA1 (340-400 nm), UVB + UVA2 (280-340 nm) and UVC (254 nm) radiations. Effects of irradiation were ascertained using cultures of HeLa cells stably transfected with the HIV promoter linked to a reporter-chloramphenicol acetyl transferase-gene. The exposures used caused at least two logs of cell killing. In this cytotoxicity range, UVA1 or X radiations had no effect on the HIV promoter, whereas UVB + UVA2 or UVC radiations activated the HIV promoter in a fluence-dependent manner. Survivals following exposure to UVB + UVA2 or UVC radiation were (1) at the lowest measurable HIV promoter activation, 30 and 20%, respectively, (2) at one-half maximal activation, 6 and 3%, respectively and (3) at the maximal activation, 0.5 and 0.2%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of ultraviolet light irradiation on viral infections

Exposure to ultraviolet radiation is associated with the development of cutaneous carcinomas, and with suppression of immune responses to a variety of antigens, including those of fungal, bacterial and parasitic origin, and contact sensitizers. UV irradiation also influences viral infections. It can affect viral mutation, the photolocalization of viral exanthems, viral oncogenesis, activation of viral genomes, and the suppression of immune responses to viruses. The evidence for, and mechanisms involved in, each of these categories is presented, and the effect of UV radiation on the virus-host interaction, particularly during persistent infections, is discussed.

General purpose lamps induce polyoma DNA replication in H3 cells

We have previously demonstrated the ability of UVC (254 nm) radiation to induce asynchronous polyoma replication in rat fibroblast cells (H3 line) that contain an integrated copy of polyoma virus. In the present study we show that general purpose lamps can induce polyoma replication in these cells as well. The amount of UV radiation emitted by three different light sources was determined and the effects of each source on the replication of polyoma DNA was assessed. Our findings indicate that a 100 W incandescent lamp had a minimal effect on replication, whereas a 90 s exposure to a halogen lamp or a 160 W mercury vapor lamp induced replication 1.5-fold and 2-fold, respectively, in comparison with nontreated controls. We have previously shown that asynchronous polyoma replication in H3 cells involves UV-inducible cellular protein factors. Our present results indicate that these factors are also activated by exposure to commonly used lamps that emit comparable doses of UV radiation.

Cyclobutane pyrimidine dimers in UV-DNA induce release of soluble mediators that activate the human immunodeficiency virus promoter

Ultraviolet (UV) irradiation of human cells induced expression of a stably maintained fusion gene consisting of the human immunodeficiency virus long terminal repeat promoter controlling the bacterial chloramphenicol acetyltransferase gene. Two experiments demonstrated that DNA damage can initiate induction: UV induction was greater in DNA repair-deficient cells from a xeroderma pigmentosum patient than in repair-proficient cells, and transfection of UV-irradiated DNA into unirradiated cells activated gene expression. Increased repair of cyclobutane pyrimidine dimers by T4 endonuclease V abrogated viral gene activation, suggesting that dimers in DNA are one signal leading to increased gene expression. This signal was spread from UV-irradiated cells to unirradiated cells by co-cultivation, implicating the release of soluble factors. Irradiation of cells from DNA repair-deficiency diseases resulted in greater release of soluble factors than irradiation of cells from unaffected individuals. These results suggest that UV-induced cyclobutane pyrimidine dimers can activate the human immunodeficiency virus promoter at least in part by a signal-transduction pathway that includes secretion of soluble mediators.

Cutaneous disorders and viral gene expression in HIV-1 transgenic mice

Patients infected with HIV-1 experience several hyperproliferative skin disorders, including seborrheic dermatitis, ichthyosis, and psoriasis. Transgenic mice carrying a subgenomic HIV-1 proviral construct lacking the gag and pol genes were found to develop proliferative epidermal lesions, manifested as diffuse epidermal hyperplasia in homozygous transgenic mice and benign papillomas in heterozygous transgenic mice. Nonpapillomatous skin from both homozygotes and heterozygotes expressed viral RNA, and the viral envelope protein gp120 was localized to the suprabasal keratinocyte. Papillomas contained increased amounts of both viral mRNA and envelope glycoprotein. Exposure of transgenic mice to doses of ultraviolet B (UV-B) irradiation that induced cutaneous injury increased viral gene expression and resulted in the development of papillomas within 14-21 days. Cutaneous injury induced by phenol and liquid nitrogen had similar effects. These data support a role for HIV-1 gene products in the pathogenesis of proliferative epidermal disorders associated with HIV-1 infection. Further, they suggest that the process of wound repair increases HIV-1 gene expression in this transgenic mouse model.

Animal models for anti-AIDS therapy

Primate and non-primate species have been used to study the pathobiology of the simian immunodeficiency virus (SIV) and of the human immunodeficiency virus type 1 (HIV-1), respectively, and to develop new therapeutic regimes. Transgenic mice which express either the entire HIV-1 provirus or subgenomic fragments have been used to analyze viral gene products in vivo and may serve as models for the development of agents targeted to select viral functions. Chimeric mice which were created by transplanting human hematolymphoid cells into mice suffering from congenital severe combined immunodeficiency (scid/scid or so called SCID mice), can be infected with HIV-1 and allow one to study the entire HIV-1 replicative cycle. Type C murine leukemia virus models have been used to develop new prophylactic and therapeutic strategies but their use is restricted to the evaluation of select antiviral drug inhibition, targeted to retroviral genes common to both Lentivirinae and Oncovirinae. The role of various animal model systems in the development of anti-HIV-1 and anti-AIDS therapies is summarized.