Superoxide enhances the spread of HIV-1 infection by cell-to-cell transmission

Conditional Human Immunodeficiency Virus Transactivator of Transcription Protein Expression Induces Depression-like Effects and Oxidative Stress

BACKGROUND

The prevalence of major depression in those with HIV/AIDS is substantially higher than in the general population. Mechanisms underlying this comorbidity are poorly understood. HIV-transactivator of transcription (Tat) protein, produced and excreted by HIV, could be involved. We determined whether conditional Tat protein expression in mice is sufficient to induce depression-like behaviors and oxidative stress. Further, as oxidative stress is associated with depression, we determined whether decreasing or increasing oxidative stress by administering methylsulfonylmethane (MSM) or diethylmaleate (DEM), respectively, altered depression-like behavior.

METHODS

GT-tg bigenic mice received intraperitoneal saline or doxycycline (Dox, 25-100 mg/kg/day) to induce Tat expression. G-tg mice, which do not express Tat protein, also received Dox. Depression-like behavior was assessed with the tail suspension test (TST) and the two-bottle saccharin/water consumption task. Reactive oxygen/nitrogen species (ROS/RNS) were assessed ex vivo. Medial frontal cortex (MFC) oxidative stress and temperature were measured in vivo with 9.4-Tesla proton magnetic resonance spectroscopy (MRS).

RESULTS

Tat expression increased TST immobility time in an exposure-dependent manner and reduced saccharin consumption. MSM decreased immobility time while DEM increased it in saline-treated GT-tg mice. Tat and MSM behavioral effects persisted for 28 days. Tat and DEM increased while MSM decreased ROS/RNS levels. Tat expression increased MFC glutathione levels and temperature.

CONCLUSIONS

Tat expression induced rapid and enduring depression-like behaviors and oxidative stress. Increasing/decreasing oxidative stress increased/decreased, respectively, depression-like behavior. Thus, Tat produced by HIV may contribute to the high depression prevalence among those with HIV. Further, mitigation of oxidative stress could reduce depression severity.

Oxidative Stress Markers in Tuberculosis and HIV/TB Co-Infection

INTRODUCTION

Dysfunction of redox homeostasis has been implicated in many pathological conditions. An imbalance of pro- and anti-oxidants have been observed in Tuberculosis (TB) and its co-morbidities especially HIV/AIDS. The pro inflammatory milieu in either condition aggravates the physiological balance of the redox mechanisms. The present study therefore focuses on assessing the redox status of patients suffering from TB and HIV-TB co-infection.

AIM

To assess the oxidative stress markers in the HIV-TB and TB study cohort.

MATERIALS AND METHODS

The current prospective study was conducted in Haffkine Institute, Parel, Maharashtra, India, during January 2013 to December 2015. Blood samples from 50 patients each suffering from active TB and HIV-TB co-infection were collected from Seth G.S.Medical College and KEM Hospital Mumbai and Group of Tuberculosis Hospital, Sewree Mumbai. Samples were processed and the experiments were carried out at the Department of Biochemistry, Haffkine Institute. Samples from 50 healthy volunteers were used as controls. Serum was assessed for pro-oxidant markers such as Nitric Oxide (NO), Thiobarbituric Acid Reactive Species (TBARS), C-Reactive Protein (CRP), superoxide anion. Antioxidant markers such as catalase and Superoxide Dismutase (SOD) were assessed. Total serum protein, was also assessed.

RESULTS

Among the pro-oxidants, serum NO levels were decreased in TB group while no change was seen in HIV-TB group. TBARS and CRP levels showed significant increase in both groups; superoxide anion increased significantly in HIV-TB group. Catalase levels showed decreased activities in TB group. SOD activity significantly increased in HIV-TB but not in TB group. The total serum proteins were significantly increased in HIV-TB and TB groups. The values of Control cohort were with the normal reference ranges.

CONCLUSION

In the present study, we found the presence of oxidative stress to be profound in the TB and HIV-TB co-infection population.

The Effectiveness of Mangosteen Peels Extract Against The Total of T Lymphocytes in HIV Patients

Introduction: The Province of West Java is one of the highest HIV sufferers in Indonesia that has increased accumulatively in 2013 to 2014. This condition was proven that in 2014 West Java ranked 4th among the provinces with the highest HIV sufferers in Indonesia. HIV has main target to infect a cell that contains of receptor, CD4. CD4 examination routinely is very important to decide HIV replication process. Meanwhile, CD4 test in the laboratory is quite expensive and not always available in every health facilities. Mangosteen peels extract contains of xanthones as an antioxidant, which is needed for body as a prooxidant that can inhibit the replication of HIV and the activity was seen from the total number of lymphocyte.Method:  The human experimental research has been done by Randomized Control Group Pretest-Post Test Design. There were 20 patients sample for each group. In group 1, HIV patients with ARV therapy were given mangosteen peels extract and in group 2, they were given placebo capsule. Wilcoxon Smith test and Mann Whitney U test were used to determine the difference between group 1 and group 2.Result: There is no significant difference between lymphocytes (p: 0.102) to HIV patients with ARV in each group examination. Discussion: The ineffectiveness is caused by the phagocytocity and cytoxity of TNF through the increasing of free radicals in HIV patients.

Nutrition- and Virus-Induced Stress Represses the Expression of Manganese Superoxide Dismutase in Vitro

The relationship between oxidative stress and neuronal cell death has been suggested for many years. To understand the influence of oxidative stress on neuronal cell death, we investigated the influence of oxidative stress on DEV cells, a human glial cell line. Using enterovirus infection and/or malnutrition to induce oxidative stress, our results demonstrate that those stressors severely influence the antioxidant defense system in DEV cells. Although the expression of mitochondrial manganese superoxide dismutase (MnSOD) in DEV cells was significantly increased in acute infection with viral and nutritional stress, in persistent infection and nutritional stress, the expression of the MnSOD was drastically downregulated. We believe that this downregulation of MnSOD expression in the chronic stress model is due to repression of antioxidant defense. The downregulation of the MnSOD expression may lead to an increase of free-radical production and thus explain why the cells in the chronic stress model were more vulnerable to other oxidative stress influences. The vulnerability of DEV cells to additional stress factors resulted in progressive cell death, which may be analogous to the cell death in neurodegenerative diseases.

Chronic Effects of Ethanol and/or Darunavir/Ritonavir on U937 Monocytic Cells: Regulation of Cytochrome P450 and Antioxidant Enzymes, Oxidative Stress, and Cytotoxicity

BACKGROUND

Our recent study has shown that acute treatment with ethanol (EtOH) increases oxidative stress and cytotoxicity through cytochrome P450 2E1 (CYP2E1)-mediated pathway in U937 monocytic cells. U937 cells are derived from blood monocytes and are considered as the model system for HIV-related study. Since the prevalence of alcohol use in HIV-infected population is high, and HIV+ patients are on antiretroviral therapy (ART) soon after they are diagnosed, it is important to study the interactions between EtOH and ART in monocytes.

METHODS

This study examined the chronic effects of EtOH and ART (darunavir/ritonavir), alone and in combination, on expression/levels of cytochrome P450 enzymes (CYPs), antioxidant enzymes (AOEs), reactive oxygen species (ROS), and cytotoxicity in U937 cells. The mRNA and protein levels were measured using quantitative reverse transcription polymerase chain reaction and Western blot, respectively. ROS and cytotoxicity were measured using flow cytometry and cell viability assay, respectively.

RESULTS

While chronic ART treatment increased CYP2E1 protein expression by 2-fold, EtOH and EtOH+ART increased CYP2E1 by ~5-fold. In contrast, ART and EtOH treatments decreased CYP3A4 protein expression by 38 ± 17% and 74 ± 15%, respectively, and the combination additively decreased CYP3A4 level by 90 ± 8%. Expressions of superoxide dismutase 1 (SOD1) and peroxiredoxin (PRDX6) were decreased by both EtOH and ART, however, the expressions of SOD2 and catalase were unaltered. These results suggested increased EtOH metabolism, increased ART accumulation, and decreased defense against ROS. Therefore, we determined the effects of EtOH and ART on ROS and cytotoxicity. While ART showed a slight increase, EtOH and EtOH+ART displayed significant increase in ROS and cytotoxicity. Moreover, the combination showed additive effects on ROS and cytotoxicity.

CONCLUSIONS

These results suggest that chronic EtOH, in the absence and presence of ART, increases ROS and cytotoxicity in monocytes, perhaps via CYP- and AOE-mediated pathways. This study has clinical implications in HIV+ alcohol users who are on ART.

Enhanced oxidative stress by alcohol use in HIV+ patients: possible involvement of cytochrome P450 2E1 and antioxidant enzymes

Background

Alcohol consumption is prevalent amongst HIV positive population. Importantly, chronic alcohol use is reported to exacerbate HIV pathogenesis. Although alcohol is known to increase oxidative stress, especially in the liver, there is no clinical evidence that alcohol increases oxidative stress in HIV positive patients. The mechanism by which alcohol increases oxidative stress in HIV positive patients is also unknown.

Methods

To examine the effects of alcohol use on oxidative stress we recruited HIV+ patients who reported mild-to-moderate alcohol use. Strict inclusion and exclusion criteria were applied to reduce the effect of other therapeutic drugs metabolized via the hepatic system as well as the effect of co-morbidities such as active tuberculosis on the interaction between alcohol and HIV infection, respectively. Blood samples were collected from HIV-negative alcohol-users and HIV positive alcohol-users followed by collection of plasma and isolation and fractionation of monocytes from peripheral blood. We then determined oxidative DNA damage, glutathione level, alcohol level, transcriptional level of cytochrome P450 2E1 (CYP2E1) and several antioxidant enzymes, and plasma level of cytokines.

Results

Compared to HIV-negative alcohol users, HIV-positive alcohol users demonstrated an increase in oxidative DNA damage in both plasma and CD14+ monocytes, as well as, a relative increase in oxidized/reduced glutathione (GSSG/GSH) in plasma samples. These results suggest an increase in oxidative stress in HIV-positive alcohol users compared with HIV-negative alcohol users. We also examined whether alcohol metabolism, perhaps by CYP2E1, and antioxidant enzymes are involved in alcohol-mediated increased oxidative stress in HIV-positive patients. The results showed a lower plasma alcohol level, which was associated with an increased level of CYP2E1 mRNA in monocytes, in HIV-positive alcohol users compared with HIV-negative alcohol users. Furthermore, the transcription of major antioxidants enzymes (catalase, SOD1, SOD2, GSTK1), and their transcription factor, Nrf2, were reduced in monocytes obtained from HIV positive alcohol users compared to the HIV-negative alcohol user group. However, no significant change in levels of five major cytokines/chemokines were observed between the two groups.

Conclusions

The data suggests that alcohol increases oxidative stress in HIV+ patients, perhaps through CYP2E1- and antioxidant enzymes-mediated pathways. The enhanced oxidative stress is accompanied by a failure of cellular antioxidant mechanisms to maintain redox homeostasis. Overall, the enhanced oxidative stress in monocytes may exacerbate HIV pathogenesis in HIV positive alcohol users.

HIV-1 infection is blocked at an early stage in cells devoid of mitochondrial DNA

Human immunodeficiency virus type I (HIV-1) exploits various host cellular pathways for efficient infection. Here we report that the absence of mitochondrial DNA (mtDNA) in ρ(0) cells markedly attenuates HIV-1 infection. Importantly, reduced infection efficiency in ρ(0) cells is not simply the result of impaired oxidative phosphorylation (OXPHOS) because pharmacological OXPHOS inhibition did not inhibit HIV-1 infection. Analysis of the early steps of virus infection by real-time PCR quantification of stage-specific HIV-1 DNA products in the infected ρ(0) and parental cell line have allowed us to conclude that HIV-1 infection in ρ(0) cells is blocked at the steps that occur after reverse transcription and prior to nuclear import. Additionally, confocal fluorescence microscope analysis showed that the majority of viral complexes containing HIV-1 p24 co-localize with mitochondria in target cells, suggesting an interaction between the two. Collectively, our data strongly indicate that mitochondria play an important role during early stages of HIV-1 infection, probably through direct association with HIV-1 intracellular complexes.

HIV-1 infection of T cells and macrophages are differentially modulated by virion-associated Hck: a Nef-dependent phenomenon

The proline repeat motif (PxxP) of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages confirmed the presence of a Nef:Hck complex which was dependent on the Nef proline repeat motif. The proline repeat motif of Nef also enhanced both HIV-1 infection and replication in macrophages, and was required for incorporation of Hck into viral particles. Unexpectedly, wild-type Hck inhibited infection of macrophages, but Hck was shown to enhance infection of primary T lymphocytes. These results indicate that the interaction between Nef and Hck is important for Nef-dependent modulation of viral infectivity. Hck-dependent enhancement of HIV-1 infection of T cells suggests that Nef-Hck interaction may contribute to the spread of HIV-1 infection from macrophages to T cells by modulating events in the producer cell, virion and target cell.

Selenium deficiency and HIV infection

Selenium is a non-metallic chemical element of great important to human health. Low selenium levels in humans are associated with several pathological conditions and are a common finding in HIV infected individuals. We conducted a review of the literature to assess if selenium deficiency or selenium supplementation could play a role in modifying the clinical course of HIV disease. Several studies investigated the role of selenium in disease progression, morbidity and mortality in HIV infected individuals. Larger studies were conducted in countries with poor economic resources and limited access to HAART. According to the majority of published studies low selenium levels appear to have an association with mortality, and selenium supplementation appears to play a beneficial role on survival or on slowing disease progression among HIV infected individuals. The role of selenium supplementation on preventing hospital admission among HIV outpatients was also noticed. The literature suggests an association between selenium deficiency and development of HIV associated cardiomyopathy and furthermore, selenium supplementation appears to improve the cardiac function in HIV infected individuals with cardiomyopathy. However, there is conflicting evidence regarding the role selenium in modifying HIV viral load and immune status in HIV infection.

Genetic variants in nuclear-encoded mitochondrial genes influence AIDS progression

BACKGROUND

The human mitochondrial genome includes only 13 coding genes while nuclear-encoded genes account for 99% of proteins responsible for mitochondrial morphology, redox regulation, and energetics. Mitochondrial pathogenesis occurs in HIV patients and genetically, mitochondrial DNA haplogroups with presumed functional differences have been associated with differential AIDS progression.

METHODOLOGY/PRINCIPAL FINDINGS

Here we explore whether single nucleotide polymorphisms (SNPs) within 904 of the estimated 1,500 genes that specify nuclear-encoded mitochondrial proteins (NEMPs) influence AIDS progression among HIV-1 infected patients. We examined NEMPs for association with the rate of AIDS progression using genotypes generated by an Affymetrix 6.0 genotyping array of 1,455 European American patients from five US AIDS cohorts. Successfully genotyped SNPs gave 50% or better haplotype coverage for 679 of known NEMP genes. With a Bonferroni adjustment for the number of genes and tests examined, multiple SNPs within two NEMP genes showed significant association with AIDS progression: acyl-CoA synthetase medium-chain family member 4 (ACSM4) on chromosome 12 and peroxisomal D3,D2-enoyl-CoA isomerase (PECI) on chromosome 6.

CONCLUSIONS

Our previous studies on mitochondrial DNA showed that European haplogroups with presumed functional differences were associated with AIDS progression and HAART mediated adverse events. The modest influences of nuclear-encoded mitochondrial genes found in the current study add support to the idea that mitochondrial function plays a role in AIDS pathogenesis.

Mitochondrial DNA haplogroups influence AIDS progression

OBJECTIVE

Mitochondrial function plays a role in both AIDS progression and HAART toxicity; therefore, we sought to determine whether mitochondrial DNA variation revealed novel AIDS restriction genes, particularly as mitochondrial DNA single-nucleotide polymorphisms are known to influence regulation of oxidative phosphorylation, reactive oxygen species production, and apoptosis.

DESIGN

This is a retrospective cohort study.

METHODS

We performed an association study of mitochondrial DNA haplogroups among 1833 European American HIV-1 patients from five US cohorts: the Multicenter AIDS Cohort Study, the San Francisco City Clinic Study, Hemophilia Growth and Development Study, the Multicenter Hemophilia Cohort Study, and the AIDS Linked to Intravenous Experiences cohort to determine whether the mitochondrial DNA haplogroup correlated with AIDS progression rate.

RESULTS

Mitochondrial DNA haplogroups J and U5a were elevated among HIV-1 infected people who display accelerated progression to AIDS and death. Haplogroups Uk, H3, and IWX appeared to be highly protective against AIDS progression.

CONCLUSION

The associations found in our study appear to support a functional explanation by which mitochondrial DNA variation among haplogroups, influencing ATP production, reactive oxygen species generation, and apoptosis, is correlated to AIDS disease progression; however, repeating these results in cohorts with different ethnic backgrounds would be informative. These data suggest that mitochondrial genes are important indicators of AIDS disease progression in HIV-1 infected persons.

Regulation of oxidative phosphorylation, the mitochondrial membrane potential, and their role in human disease

Thirty years after Peter Mitchell was awarded the Nobel Prize for the chemiosmotic hypothesis, which links the mitochondrial membrane potential generated by the proton pumps of the electron transport chain to ATP production by ATP synthase, the molecular players involved once again attract attention. This is so because medical research increasingly recognizes mitochondrial dysfunction as a major factor in the pathology of numerous human diseases, including diabetes, cancer, neurodegenerative diseases, and ischemia reperfusion injury. We propose a model linking mitochondrial oxidative phosphorylation (OxPhos) to human disease, through a lack of energy, excessive free radical production, or a combination of both. We discuss the regulation of OxPhos by cell signaling pathways as a main regulatory mechanism in higher organisms, which in turn determines the magnitude of the mitochondrial membrane potential: if too low, ATP production cannot meet demand, and if too high, free radicals are produced. This model is presented in light of the recently emerging understanding of mechanisms that regulate mammalian cytochrome c oxidase and its substrate cytochrome c as representative enzymes for the entire OxPhos system.

Micronutrient supplementation increases CD4 count in HIV-infected individuals on highly active antiretroviral therapy: a prospective, double-blinded, placebo-controlled trial

OBJECTIVE

To examine the immunologic, metabolic, and clinical effects of broad spectrum micronutrient supplementation in HIV-infected patients taking highly active antiretroviral therapy (HAART).

DESIGN

A prospective, randomized, double-blinded, placebo-controlled trial.

METHODS

Forty HIV-infected patients taking a stavudine and/or didanosine-based HAART regimen were prospectively randomized to receive micronutrients or placebo twice daily for 12 weeks. Data were collected at 4-week intervals including immunologic, metabolic, and clinical measurements. The study examined the effect of micronutrient supplementation on immunologic parameters as the primary end point. The secondary end points were metabolic and clinical effects and distal symmetrical polyneuropathy.

RESULTS

The mean absolute CD4 count increased by an average of 65 cells in the micronutrient group versus a 6-cell decline in the placebo group at 12 weeks (P = 0.029). The absolute CD4 count increased by an average of 24% in the micronutrient group versus a 0% change in the placebo group (P = 0.01). The mean HIV-1 RNA decreased in the micronutrient supplementation group, although not significantly. Neuropathy scores improved in the micronutrient group by 42% compared with a 33% improvement in the placebo arm. This difference did not reach statistical significance. Fasting serum glucose, insulin, and lipids were not adversely affected in the patients taking the micronutrients.

CONCLUSIONS

Micronutrient supplementation can significantly improve CD4 cell count reconstitution in HIV-infected patients taking HAART. The micronutrient supplement tested was well tolerated and may hold promise as an adjuvant therapy in the treatment of HIV. Further investigation is warranted.

Does measurement of oxidative damage to DNA have clinical significance?

Oxidative damage to DNA is the seemingly inevitable consequence of cellular metabolism. Furthermore, despite protective mechanisms, cellular levels of damage may increase under conditions of oxidative stress, arising from exposure to a variety of physical or chemical insults. Elevated levels of oxidatively damaged DNA have been measured in numerous diseases, and as a result, it has been hypothesised that such damage plays an integral role in the aetiology of that disease. This review examines the validity of this hypothesis, exploring the mechanisms by which oxidative DNA damage may lead to disease. We conclude that further validation of biomarkers of oxidative DNA damage, along with further elucidation of the role of damage in disease, may allow these biomarkers to become potentially useful clinical tools.

A clinical review of micronutrients in HIV infection

This article reviews current literature on the role of micronutrients in human immunodeficiency virus (HIV) infection. Deficiencies of micronutrients are common in HIV-infected persons. They occur due to malabsorption, altered metabolism, gut infection, and altered gut barrier function. There is a compelling association of deficiencies of micronutrients in HIV-infection with immune deficiency, rapid disease progression, and mortality. Also, there is increased risk of vertical HIV transmission from mother to child with deficiency of vitamin A, and of neurological impairment with vitamin B12. The last five years have been exciting in micronutrient research, and there is promise that some micronutrients may be key factors in maintaining health in HIV immunodeficiency, and in reducing mortality. Selenium appears important in reducing virulence of HIV and slowing disease progression. Vitamin A supplementation in pregnant women with HIV may reduce maternal mortality and improve birth outcomes. Supplementation in children with HIV may accelerate growth. Carotenoid supplementation is being evaluated. Vitamin B12 may slow HIV immune deficiency disease progression, and reverse neurological compromise. Clinical benefit of supplementation with some micronutrients may be measurable in the presence of pre-existing deficiency. Apart from improved general nutrition, the impact of micronutrient supplements on health and their optimal use in HIV infection is controversial because there are so few controlled clinical trials. Further research is needed to elucidate the role of micronutrient deficiencies on the course of HIV infection, and the preventive and therapeutic role of supplementation in its clinical management. Nevertheless, current knowledge supports the use of routine multivitamin and trace element supplementation as adjuvant to conventional antiretroviral drug treatment as a relatively low-cost intervention.

Oxidative DNA damage: assessment of the role in carcinogenesis, atherosclerosis, and acquired immunodeficiency syndrome

Free radical attack upon DNA generates a multiplicity of DNA damage, including modified bases. Some of these modifications have considerable potential to damage the integrity of the genome. This article reviews recent data that suggest the involvement of oxidative DNA damage in carcinogenesis, atherosclerosis, and acquired immunodeficiency syndrome (AIDS). There is evidence that oxidative DNA damage may play a causative role in atherosclerosis. Oxidative DNA damage may lead to apoptotic cell death of patients infected with human immunodeficiency virus (HIV) and may influence the progression of AIDS. While many details regarding the role of reactive oxygen species-induced DNA damage in the etiology of complex multifactorial diseases like cancer are yet to be discovered, evidence suggests that oxidants act at several stages in the malignant transformation of cells. However, the quantitative relationship between the measured DNA damage and the development of cancer is still lacking.

Supplementation with antioxidant vitamins prevents oxidative modification of DNA in lymphocytes of HIV-infected patients

There is evidence suggesting that patients infected with human immunodeficiency virus (HIV) are under chronic oxidative stress. In the present study, the level of oxidatively modified bases in lymphocyte DNA and some other parameters of oxidative stress were measured in HIV-infected patients (n = 30), as well as in control groups (10 healthy volunteers and 15 HIV-seronegative injected drug users). Additional experiments were conducted using lymphocyte DNA samples from asymptomatic seropositive, HIV-infected patients who were supplemented with antioxidant vitamins A, C, and E or received placebo. Significant increases in the amount of the modified DNA bases were observed in HIV-infected patients when compared with the control group. The concentration of thiobarbituric acid reactive substances (TBARS) was higher and activities of antioxidant enzymes (superoxide dismutase and catalase) were lower in the group of HIV-infected patients in comparison to the control group. Vitamin supplementation resulted in the significant decrease in the levels of all modified DNA bases when compared to the patients who received placebo. The reduction of TBARS and the restoration of the activity of the enzymes were also observed. Our data suggest that people infected with HIV can benefit from treatment with antioxidant vitamins.

Oxidative modifications of kynostatin-272, a potent human immunodeficiency virus type 1 protease inhibitor: potential mechanism for altered activity in monocytes/macrophages

Previous studies have indicated that human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) are less active at blocking viral replication in HIV-1 infected peripheral blood monocytes/macrophages (M/M) than in HIV-1-infected T cells. We explored the hypothesis that oxidative modification and/or metabolism of the PIs in M/M might account for this reduced potency. We first tested the susceptibility of several PIs (kynostatin-272 [KNI-272], saquinavir, indinavir, ritonavir, or JE-2147) to oxidation after exposure to hydrogen peroxide (H(2)O(2)): only KNI-272 was highly susceptible to oxidation. Treatment of KNI-272 with low millimolar concentrations of H(2)O(2) resulted in mono-oxidation of the sulfur in the S-methyl cysteine (methioalanine) moiety, as determined by reversed-phase high-performance liquid chromatography and mass spectrometry (RP-HPLC/MS). Higher concentrations of H(2)O(2) led to an additional oxidation of the sulfur in the thioproline moiety of KNI-272. None of the PIs were metabolized or oxidized when added to T cells and cultured for up to 12 days. However, when KNI-272 was added to M/M, the concentration of the original KNI-272 steadily decreased with a corresponding increase in the production of three KNI-272 metabolites as identified by RP-HPLC/MS. The structures of these metabolites were different from those produced by H(2)O(2) treatment. The two major products of M/M metabolism of KNI-272 were identified as isomeric forms of KNI-272 oxidized solely on the thioproline ring. Both metabolites had reduced capacities to inhibit HIV-1 protease activity when tested in a standard HIV-1 protease assay. These studies demonstrate that antiviral compounds can be susceptible to oxidative modification in M/M and that this can affect their antiviral potency.

Placental morphogenesis in pregnancies with Down's syndrome might provide a clue to pre-eclampsia

Insufficient perfusion of placenta in pre-eclampsia is commonly associated with oxidative stress leading to increased superoxide formation and reduced invasion of uterine spiral arteries by differentiated migratory cytotrophoblasts. The superoxide dismutase (SOD) level, responsible for eliminating toxic superoxides, drops significantly in pre-eclampsia. On the contrary, the SOD synthesis increases dramatically, compared to that of normal placenta, in pregnancies with trisomy 21 (T21) fetus. However, despite a low level of placental hypoplasia, the overall perfusion of T21 placentae is comparable to that of normal pregnancy. In the light of recent reports on alternative modes of SOD function and factors regulating pathways of cytotrophoblast differentiation, here we have attempted to reconcile the two seemingly disparate pregnancy conditions and suggest that trisomy 21 pregnancies might provide new insight into our understanding of placental morphogenesis in pre-eclampsia.

Protective effects of the lipophilic redox conjugate tocopheryl succinyl-ethyl ferulate on HIV replication

Previously, we demonstrated that ferulate ethyl and tocopherol reduced HIV replication. In this study, we investigate whether the conjugation of both compounds (O-tocopheryl succinyl O-ethyl ferulate) can increase HIV inhibition. We show here for the first time that O-tocopheryl succinyl O-ethyl ferulate inhibits 80% of HIV replication (HIV-1 acute infection and HIV transmission), inhibits cell lipoperoxidation and prevents cellular glutathione consumption. Compared to ferulate ethyl and tocopheryl succinyl, O-tocopheryl succinyl O-ethyl ferulate inhibits more HIV replication. This may be due in part to the great increase in the lipophilicity of this compound.

Clastogenic factors in plasma of HIV-1 infected patients activate HIV-1 replication in vitro: inhibition by superoxide dismutase

The frequent neoplastic disorders present in HIV-infected patients and the implication of oxidative stress in AIDS-Kaposi's sarcoma pathogenesis prompted us to study whether the mechanisms implicated in genotoxic effects of clastogenic factors (CFs) (i.e., chromosome damaging materials released by cells under conditions of oxidant stress) can play a role in HIV-1 expression and whether exogenous superoxide dismutase can inhibit the clastogenic and HIV-inducing effects of CFs. CFs were found in the plasma of all HIV-1 infected patients (n = 21) of this study group, in asymptomatic (CDC II) as well as in symptomatic patients (CDC IV). In addition to their chromosome damaging effect, CFs are able to upregulate HIV-1 expression in U1 cells and in PBMCs activated with PHA and IL2 at all time points (p < .05). Their formation, therefore, is an early event in the disease. It occured despite antiviral medication in these patients. Superoxide dismutase inhibited the clastogenic and the viral inducing effects (p < .05). On the basis of our findings, association of SOD mimetics or superoxide scavengers with antiviral drugs may be a new therapeutic approach. This polytherapy, if started early enough after infection, may prolong the latency period and limit the emergence of drug-resistant viral strains.

Intracellular glutathione as a possible direct blocker of HIV type 1 reverse transcription

In AIDS patients, chronic inflammation and elevated levels of cytokines seem to be associated with reduced levels of glutathione (GSH). GSH has been proposed to inhibit the activation of NF-kB, which results in the inhibition of HIV-1 replication. Here, we show the evidence that GSH and N-acetylcysteine, but not L-cysteine or dithiothreitol, could inhibit the reverse transcriptase (RT) process of HIV-1. Such inhibition was not observed with the RT of murine leukemia virus.

Stimulation of human immunodeficiency virus type 1 infected cells with superoxide enhances the chemotactic motile response of CD4+ human T cells: implication for virus transmission by cell-to-cell interaction

We previously showed that superoxide (O2-) significantly enhanced human immunodeficiency virus type 1 (HIV-1)-induced syncytia formation in co-cultured infected and uninfected human T cells. In this study, we describe a novel chemotactic response of uninfected CD4+ T cells by stimulating infected T cells with O2-. Syncytia formation was amplified only when persistently infected cells were stimulated by O2-. When the infected cells in lower well of microplate were cultured with uninfected cells in the upper well of a Boyden chamber with 8.0 microns pores, uninfected cell migration to the porous membrane was significantly amplified by stimulating infected cells with O2-. In contrast, similar functions were slight under the same assay conditions in the presence of known chemokines such as human RANTES and macrophage inflammatory protein 1 (MIP-1 alpha and beta), which all activate T lymphocytes. In addition, it is unlikely that the O2(-)-induced chemotactic response is due to soluble HIV-1 proteins from infected cells or to amplified expression levels of cell surface functional molecules such as CD4 and LFA-1 (CD11a and CD18) as well as HIV-1 Env gp120 on uninfected and/or infected cells. Thus, an unknown chemotactic factor could be generated from infected T cells by stimulation with O2- and it might contribute to viral transmission by activating cell-to-cell interactions.

High susceptibility of U937-derived subclones to infection with human immunodeficiency virus type 1 is correlated with virus-induced cell differentiation and superoxide generation

The promonocytic human leukemic cell line U937, when infected with lymphotropic human immunodeficiency virus type 1 (HIV-1), becomes a continuous virus producer. A total of 46 U937-derived subclones in suspension was isolated and classified into three (2 high, 42 middle, and 2 low) types based on their susceptibility to the infection. By analyzing subclones before infection, we found that the high-type subclones expressed LFA-1 antigens at a relatively low level. In addition, the ability of these subclones to induce adherence after exposure to phorbol 12-myristate 13-acetate (PMA) was reduced. In contrast, a transition by HIV-1 infection to adherent macrophage-like cells was induced only in the high-type, but not in the low-type subclones. The high-type adherent cells obtained by HIV-1 infection were followed by further lineage to become retrodifferentiated suspension cells showing reduced syncytia formation ability. Superoxide was generated in the high-type subclones, without PMA-mediated differentiation, from the early stage of infection before HIV-1 replication, as well as during undifferentiated, differentiated and retrodifferentiated stages. In contrast, it was only transiently generated at acute phase of HIV-1 replication in low-type subclones. Long-term culture of the low-type subclones decreased the expression of major structural viral protein Gag and also virus production. Thus, the mechanism by which PMA differentiates U937 cells is not the same as that induced by HIV-1 infection. The latter mechanism results in high susceptibility to infection. The HIV-1 phenotypes of finally obtained persistently infected cells were also affected by the cell stages at the time of infection.

Viral activation from latency during retrodifferentiation of U937 cells exposed to phorbol ester followed by infection with human immunodeficiency virus type 1

To determine the mechanism underlying the human immunodeficiency virus type 1 (HIV-1) latency and its activation in monocyte/macrophage lineage, the human promonocytic cell line U937 was infected with HIV-1 after differentiation with varied doses of phorbol 12-myristate 13-acetate (PMA). Variously differentiated intermediate stages were generated in U937 cells in a dose-dependent manner. When these cells were infected with lymphotropic HIV-1, the kinetics of the production of HIV-1 DNA, the appearance of HIV-1 antigen-positive cells, and viral production in the conditioned media were slower at higher doses of PMA. This different susceptibility to the infection was not due to the rate of HIV-1 adsorption. Viral replication from latency in the differentiated cells was activated in proportion with the retrodifferentiation observed in long-term cultures of the host cells. Thus, our data demonstrate the close correlation between the regulation of HIV-1 replication and the differentiation stage of monocyte/macrophage lineage cells at the time of HIV-1 infection. The retrodifferentiation phenomenon in infected cells seems to be particularly important for understanding the mechanisms for HIV-1 activation from latency.