Glutathione and N-acetylcysteine suppression of human immunodeficiency virus replication in human monocyte/macrophages in vitro

Molecular Mechanisms of N-Acetylcysteine in RSV Infections and Air Pollution-Induced Alterations: A Scoping Review

N-acetylcysteine (NAC) is a mucolytic agent with antioxidant and anti-inflammatory properties. The respiratory syncytial virus (RSV) is one of the most important etiological factors of lower respiratory tract infections, and exposure to air pollution appears to be additionally associated with higher RSV incidence and disease severity. We aimed to systematically review the existing literature to determine which molecular mechanisms mediate the effects of NAC in an RSV infection and air pollution, and to identify the knowledge gaps in this field. A search for original studies was carried out in three databases and a calibrated extraction grid was used to extract data on the NAC treatment (dose, timing), the air pollutant type, and the most significant mechanisms. We identified only 28 studies conducted in human cellular models (n = 18), animal models (n = 7), and mixed models (n = 3). NAC treatment improves the barrier function of the epithelium damaged by RSV and air pollution, and reduces the epithelial permeability, protecting against viral entry. NAC may also block RSV-activated phosphorylation of the epidermal growth factor receptor (EGFR), which promotes endocytosis and facilitates cell entry. EGFR also enhances the release of a mucin gene, MUC5AC, which increases mucus viscosity and causes goblet cell metaplasia; the effects are abrogated by NAC. NAC blocks virus release from the infected cells, attenuates the cigarette smoke-induced shift from necrosis to apoptosis, and reverses the block in IFN-γ-induced antiviral gene expression caused by the inhibited Stat1 phosphorylation. Increased synthesis of pro-inflammatory cytokines and chemokines is induced by both RSV and air pollutants and is mediated by the nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways that are activated in response to oxidative stress. MCP-1 (monocyte chemoattractant protein-1) and RANTES (regulated upon activation, expressed and secreted by normal T cells) partially mediate airway hyperresponsiveness (AHR), and therapeutic (but not preventive) NAC administration reduces the inflammatory response and has been shown to reduce ozone-induced AHR. Oxidative stress-induced DNA damage and cellular senescence, observed during RSV infection and exposure to air pollution, can be partially reversed by NAC administration, while data on the emphysema formation are disputed. The review identified potential common molecular mechanisms of interest that are affected by NAC and may alleviate both the RSV infection and the effects of air pollution. Data are limited and gaps in knowledge include the optimal timing or dosage of NAC administration, therefore future studies should clarify these uncertainties and verify its practical use.

Protective role of N-acetylcysteine and Sulodexide on endothelial cells exposed on patients' serum after SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus-2 causes hyperinflammation and activation of coagulation cascade and, as a result, aggravates endothelial cell dysfunction. N-acetylcysteine and Sulodexide have been found to mitigate endothelial damage. The influence on coronary artery endothelial cells of serum collected after 4 ± 1 months from coronavirus infection was studied. The concentrations of serum samples of interleukin 6, von Willebrand Factor, tissue Plasminogen Activator, and Plasminogen Activator Inhibitor-1 were studied. The cultures with serum of patients after coronavirus infection were incubated with N-acetylcysteine and Sulodexide to estimate their potential protective role. The blood inflammatory parameters were increased in the group of cultures incubated with serum from patients after coronavirus infection. Supplementation of the serum from patients after coronavirus infection with N-acetylcysteine or Sulodexide reduced the synthesis of interleukin 6 and von Willebrand Factor. No changes in the synthesis of tissue Plasminogen Activator were observed. N-acetylcysteine reduced the synthesis of Plasminogen Activator Inhibitor-1. N-acetylcysteine and Sulodexide increased the tPA/PAI-1 ratio. N-acetylcysteine may have a role in reducing the myocardial injury occurring in the post-COVID-19 syndrome. Sulodexide can also play a protective role in post-COVID-19 patients.

Does the use of cysteine-rich whey protein supplements (Inmunocal®) improve the health well-being of COVID-19 patients? A qualitative study

<b>Introduction:</b> In the context of SARS-CoV-2 infection, it has been proposed that oxidative stress may contribute to the management of COVID-19 severity. The impact on the well-being of patients with COVID-19 using cysteine-providing supplements has not yet been evaluated and there is a need to understand the benefits and limitations they may offer.<br /> <b>Aim:</b> The aim of this study is to understand the experiences of improved well-being with cysteine-rich whey protein supplementation (Immunocal®) in patients with COVID-19.<br /> <b>Methods:</b> A qualitative study was conducted by conducting semi-structured interviews with four participants taking Immunocal® while they had COVID-19. Participants were randomly recruited through internet networking. Ethical approval was obtained from the University ethics committee. Participants were informed of the study objectives two days in advance and consent was obtained before interviews began. We used the 16-item “Use of Immunocal supplement for COVID-19” (USIC-19) questionnaire to inquire about COVID-19 behavior (time of illness, symptoms, and severity of illness) and the experience of using the supplement during illness. Confidentiality was maintained throughout this study.<br /> <b>Results:</b> All participants presented mild discomfort such as headache, weakness, and tiredness when they had COVID-19 impacting most of them emotionally. The use of Immunocal® produced a partial improvement in all patients as only two continued to experience fatigue. Immunocal® improved the mood (50%) and physical health of the participants. In addition, participants reported that the supplement was recommended and dosed primarily by a consultant and that they did not feel hesitant to use it because of previous experiences of friends and family. The daily dosage of half of the participants was two sachets and all felt the need to consume the supplement which resulted in daily use.<br /> <b>Conclusion:</b> Following the daily dosage indications of the consultants, the participants who have consumed Inmunocal® have presented a partial improvement of the symptoms related to COVID-19, however, they feel the need to consume the supplement daily to improve their quality of life.

Role of miR-2392 in driving SARS-CoV-2 infection

MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation that have a major impact on many diseases and provide an exciting avenue toward antiviral therapeutics. From patient transcriptomic data, we determined that a circulating miRNA, miR-2392, is directly involved with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) machinery during host infection. Specifically, we show that miR-2392 is key in driving downstream suppression of mitochondrial gene expression, increasing inflammation, glycolysis, and hypoxia, as well as promoting many symptoms associated with coronavirus disease 2019 (COVID-19) infection. We demonstrate that miR-2392 is present in the blood and urine of patients positive for COVID-19 but is not present in patients negative for COVID-19. These findings indicate the potential for developing a minimally invasive COVID-19 detection method. Lastly, using in vitro human and in vivo hamster models, we design a miRNA-based antiviral therapeutic that targets miR-2392, significantly reduces SARS-CoV-2 viability in hamsters, and may potentially inhibit a COVID-19 disease state in humans.

The role of oxidative stress in HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) are a leading cause of morbidity in up to 50% of individuals living with HIV, despite effective treatment with antiretroviral therapy (ART). Current evidence suggests that chronic inflammation associated with HIV is especially attributed to the dysregulated production of reactive oxygen species (ROS) that contribute to neurodegeneration and poor clinical outcomes. While ROS have beneficial effects in eliciting immune responses to infection, chronic ROS production causes damage to macromolecules such as DNA and lipids that has been linked to altered redox homeostasis associated with antioxidant dysregulation. As a result, this disruption in the balance between antioxidant-dependent mechanisms of ROS inactivation and ROS production by enzymes such as the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family, as well as from the electron transport chain of the mitochondria can result in oxidative stress. This is particularly relevant to the brain, which is exquisitely susceptible to oxidative stress due to its inherently high lipid concentration and ROS levels that have been linked to many neurodegenerative diseases that have similar stages of pathogenesis to HAND. In this review, we discuss the possible role and mechanisms of ROS production leading to oxidative stress that underpin HAND pathogenesis even when HIV is suppressed by current gold-standard antiretroviral therapies. Furthermore, we highlight that pathological ROS can serve as biomarkers for HIV-dependent HAND, and how manipulation of oxidative stress and antioxidant-dependent pathways may facilitate novel strategies for HIV cure.

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Production of reactive oxygen species has been linked to neurodegenerative diseases.

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ROS production contributes to HIV-associated neurocognitive disorders.

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ROS may be used as a biomarker for HIV-associated neurocognitive disorders.

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Manipulation of antioxidant pathways may present novel HIV cure strategies.

The Great Deceiver: miR-2392's Hidden Role in Driving SARS-CoV-2 Infection

MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional gene regulation that have a major impact on many diseases and provides an exciting avenue towards antiviral therapeutics. From patient transcriptomic data, we have discovered a circulating miRNA, miR-2392, that is directly involved with SARS-CoV-2 machinery during host infection. Specifically, we show that miR-2392 is key in driving downstream suppression of mitochondrial gene expression, increasing inflammation, glycolysis, and hypoxia as well as promoting many symptoms associated with COVID-19 infection. We demonstrate miR-2392 is present in the blood and urine of COVID-19 positive patients, but not detected in COVID-19 negative patients. These findings indicate the potential for developing a novel, minimally invasive, COVID-19 detection method. Lastly, using in vitro human and in vivo hamster models, we have developed a novel miRNA-based antiviral therapeutic that targets miR-2392, significantly reduces SARS-CoV-2 viability in hamsters and may potentially inhibit a COVID-19 disease state in humans.

Drug Repurposing Approach, Potential Drugs, and Novel Drug Targets for COVID-19 Treatment

Novel coronavirus first appeared in Wuhan, China, in December 2019, and it speedily expanded globally. Some medications which are used to treat other diseases seem to be effective in treating COVID-19 even without explicit support. The existing drugs that are summarized in this review primarily focused on therapeutic agents that possessed activity against other RNA viruses such as MERS-CoV and SARS-CoV. Drug repurposing or repositioning is a promising field in drug discovery that identifies new therapeutic opportunities for existing drugs such as corticosteroids, RNA-dependent RNA polymerase inhibitors, interferons, protease inhibitors, ivermectin, melatonin, teicoplanin, and some others. A search for new drug/drug targets is underway. Thus, blocking coronavirus structural protein, targeting viral enzyme, dipeptidyl peptidase 4, and membrane fusion blocker (angiotensin-converting enzyme 2 and CD147 inhibitor) are major sites based on molecular targets for the management of COVID-19 infection. The possible impact of biologics for the management of COVID19 is promising and includes a wide variety of options such as cytokines, nucleic acid-based therapies targeting virus gene expression, bioengineered and vectored antibodies, and various types of vaccines. This review demonstrates that the available data are not sufficient to suggest any treatment for the eradication of COVID-19 to be used at the clinical level. This article aims to review the roles of existing drugs and drug targets for COVID-19 treatment.

Intracellular Redox-Modulated Pathways as Targets for Effective Approaches in the Treatment of Viral Infection

Host-directed therapy using drugs that target cellular pathways required for virus lifecycle or its clearance might represent an effective approach for treating infectious diseases. Changes in redox homeostasis, including intracellular glutathione (GSH) depletion, are one of the key events that favor virus replication and contribute to the pathogenesis of virus-induced disease. Redox homeostasis has an important role in maintaining an appropriate Th1/Th2 balance, which is necessary to mount an effective immune response against viral infection and to avoid excessive inflammatory responses. It is known that excessive production of reactive oxygen species (ROS) induced by viral infection activates nuclear factor (NF)-kB, which orchestrates the expression of viral and host genes involved in the viral replication and inflammatory response. Moreover, redox-regulated protein disulfide isomerase (PDI) chaperones have an essential role in catalyzing formation of disulfide bonds in viral proteins. This review aims at describing the role of GSH in modulating redox sensitive pathways, in particular that mediated by NF-kB, and PDI activity. The second part of the review discusses the effectiveness of GSH-boosting molecules as broad-spectrum antivirals acting in a multifaceted way that includes the modulation of immune and inflammatory responses.

N-Acetylcysteine to Combat COVID-19: An Evidence Review

The novel coronavirus disease (COVID-19) is caused by a virus (SARS-Cov-2) and is known for inducing multisystem organ dysfunction associated with significant morbidity and mortality. Current therapeutic strategies for COVID-19 have failed to effectively reduce mortality rate, especially for elderly patients. A newly developed vaccine against SARS-Cov-2 has been reported to induce the production of neutralizing antibodies in young volunteers. However, the vaccine has shown limited benefit in the elderly, suggesting an age-dependent immune response. As a result, exploring new applications of existing medications could potentially provide valuable treatments for COVID-19. N-acetylcysteine (NAC) has been used in clinical practice to treat critically ill septic patients, and more recently for COVID-19 patients. NAC has antioxidant, anti-inflammatory and immune-modulating characteristics that may prove beneficial in the treatment and prevention of SARS-Cov-2. This review offers a thorough analysis of NAC and discusses its potential use for treatment of COVID-19.

Rationale for the use of N-acetylcysteine in both prevention and adjuvant therapy of COVID-19

COVID‐19 may cause pneumonia, acute respiratory distress syndrome, cardiovascular alterations, and multiple organ failure, which have been ascribed to a cytokine storm, a systemic inflammatory response, and an attack by the immune system. Moreover, an oxidative stress imbalance has been demonstrated to occur in COVID‐19 patients. N‐ Acetyl‐L‐cysteine (NAC) is a precursor of reduced glutathione (GSH). Due to its tolerability, this pleiotropic drug has been proposed not only as a mucolytic agent, but also as a preventive/therapeutic agent in a variety of disorders involving GSH depletion and oxidative stress. At very high doses, NAC is also used as an antidote against paracetamol intoxication. Thiols block the angiotensin‐converting enzyme 2 thereby hampering penetration of SARS‐CoV‐2 into cells. Based on a broad range of antioxidant and anti‐inflammatory mechanisms, which are herein reviewed, the oral administration of NAC is likely to attenuate the risk of developing COVID‐19, as it was previously demonstrated for influenza and influenza‐like illnesses. Moreover, high‐dose intravenous NAC may be expected to play an adjuvant role in the treatment of severe COVID‐19 cases and in the control of its lethal complications, also including pulmonary and cardiovascular adverse events.

Micronutrients as immunomodulatory tools for COVID-19 management

COVID-19 rapidly turned to a global pandemic posing lethal threats to overwhelming health care capabilities, despite its relatively low mortality rate. The clinical respiratory symptoms include dry cough, fever, anosmia, breathing difficulties, and subsequent respiratory failure. No known cure is available for COVID-19. Apart from the anti-viral strategy, the supports of immune effectors and modulation of immunosuppressive mechanisms is the rationale immunomodulation approach in COVID-19 management. Diet and nutrition are essential for healthy immunity. However, a group of micronutrients plays a dominant role in immunomodulation. The deficiency of most nutrients increases the individual susceptibility to virus infection with a tendency for severe clinical presentation. Despite a shred of evidence, the supplementation of a single nutrient is not promising in the general population. Individuals at high-risk for specific nutrient deficiencies likely benefit from supplementation. The individual dietary and nutritional status assessments are critical for determining the comprehensive actions in COVID-19.

IFN- protects primary macrophages against HIV infection

IFN-ε is a unique type I IFN that is not induced by pattern recognition response elements. IFN-ε is constitutively expressed in mucosal tissues, including the female genital mucosa. Although the direct antiviral activity of IFN-ε was thought to be weak compared with IFN-α, IFN-ε controls Chlamydia muridarum and herpes simplex virus 2 in mice, possibly through modulation of immune response. We show here that IFN-ε induces an antiviral state in human macrophages that blocks HIV-1 replication. IFN-ε had little or no protective effect in activated CD4⁺ T cells or transformed cell lines unless activated CD4⁺ T cells were infected with replication-competent HIV-1 at a low MOI. The block to HIV infection of macrophages was maximal after 24 hours of treatment and was reversible. IFN-ε acted on early stages of the HIV life cycle, including viral entry, reverse transcription, and nuclear import. The protection did not appear to operate through known type I IFN-induced HIV host restriction factors, such as APOBEC3A and SAMHD1. IFN-ε-stimulated immune mediators and pathways had the signature of type I IFNs but were distinct from IFN-α in macrophages. IFN-ε induced significant phagocytosis and ROS, which contributed to the block to HIV replication. These findings indicate that IFN-ε induces an antiviral state in macrophages that is mediated by different factors than those induced by IFN-α. Understanding the mechanism of IFN-ε-mediated HIV inhibition through immune modulation has implications for prevention.

Inhibition of rotavirus ECwt infection in ICR suckling mice by N-acetylcysteine, peroxisome proliferator-activated receptor gamma agonists and cyclooxygenase-2 inhibitors

Live attenuated vaccines have recently been introduced for preventing rotavirus disease in children. However, alternative strategies for prevention and treatment of rotavirus infection are needed mainly in developing countries where low vaccine coverage occurs. In the present work, N-acetylcysteine (NAC), ascorbic acid (AA), some nonsteroidal anti-inflammatory drugs (NSAIDs) and peroxisome proliferator-activated receptor gamma (PPARγ) agonists were tested for their ability to interfere with rotavirus ECwt infectivity as detected by the percentage of viral antigen-positive cells of small intestinal villi isolated from ECwt-infected ICR mice. Administration of 6 mg NAC/kg every 8 h for three days following the first diarrhoeal episode reduced viral infectivity by about 90%. Administration of AA, ibuprofen, diclofenac, pioglitazone or rosiglitazone decreased viral infectivity by about 55%, 90%, 35%, 32% and 25%, respectively. ECwt infection of mice increased expression of cyclooxygenase-2, ERp57, Hsc70, NF-κB, Hsp70, protein disulphide isomerase (PDI) and PPARγ in intestinal villus cells. NAC treatment of ECwt-infected mice reduced Hsc70 and PDI expression to levels similar to those observed in villi from uninfected control mice. The present results suggest that the drugs tested in the present work could be assayed in preventing or treating rotaviral diarrhoea in children and young animals.

N-Acetylcysteine treatment of rotavirus-associated diarrhea in children

Rotaviruses are the leading cause of severe, acute, and dehydrating diarrhea affecting children under 5 years of age worldwide. Despite an important reduction in rotavirus-caused deaths as a consequence of the rotavirus vaccine, alternative or complementary strategies for preventing or treating rotavirus-associated diarrhea are needed mainly in the poorest countries. We describe the cases of four rotavirus-unvaccinated 12-13-month-old girls and a 5-year-old boy who developed rotavirus-associated diarrhea confirmed by enzyme-linked immunosorbent assay, Western blotting, and immunochemistry analyses. After the first day of diarrheal episodes, three of the five patients were immediately administered oral N-acetylcysteine (NAC) 60 mg/kg daily, divided into three equal doses every 8 hours. The other two patients did not receive NAC and served as controls. Administration of NAC resulted in a decreased number of diarrheal episodes, excretion of fecal rotavirus antigen, and resolution of symptoms after 2 days of treatment. Our results suggest that NAC treatment after the first diarrheal episode could be an efficient strategy for treating rotavirus-affected children and preventing the associated severe life-threatening accompanying dehydration.

Thimerosal exposure and the role of sulfation chemistry and thiol availability in autism

Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of the children experience a developmental regression characterized by a loss of previously acquired skills and abilities. Typically reported are losses of verbal, nonverbal, and social abilities. Several recent studies suggest that children diagnosed with an ASD have abnormal sulfation chemistry, limited thiol availability, and decreased glutathione (GSH) reserve capacity, resulting in a compromised oxidation/reduction (redox) and detoxification capacity. Research indicates that the availability of thiols, particularly GSH, can influence the effects of thimerosal (TM) and other mercury (Hg) compounds. TM is an organomercurial compound (49.55% Hg by weight) that has been, and continues to be, used as a preservative in many childhood vaccines, particularly in developing countries. Thiol-modulating mechanisms affecting the cytotoxicity of TM have been identified. Importantly, the emergence of ASD symptoms post-6 months of age temporally follows the administration of many childhood vaccines. The purpose of the present critical review is provide mechanistic insight regarding how limited thiol availability, abnormal sulfation chemistry, and decreased GSH reserve capacity in children with an ASD could make them more susceptible to the toxic effects of TM routinely administered as part of mandated childhood immunization schedules.

Inhibition of rotavirus infection in cultured cells by N-acetyl-cysteine, PPARγ agonists and NSAIDs

Although the current rotavirus vaccines have shown good tolerance and significant efficacy, it would be useful to develop alternative or complementary strategies aimed at preventing or treating acute diarrhoeal disease caused by this viral agent. A variety of antiviral strategies other than vaccines have been assayed for rotavirus infection management. The recently demonstrated sensitivity of rotavirus infectivity to thiol/disulfide reagents prompted assays for screening drugs that potentially affect cellular redox reactions. MA104 or Caco-2 cells were inoculated with the rotavirus strains RRV, Wa, Wi or M69 and then incubated with different concentrations of drugs belonging to a selected group of 60 drugs that are currently used in humans for purposes other than rotavirus infection treatment. Eighteen of these drugs were able to inhibit rotavirus infectivity to different extents. A more systematic evaluation was performed with drugs that could be used in children such as N-acetylcysteine and ascorbic acid, in addition to ibuprofen, pioglitazone and rosiglitazone, all of which affecting cellular pathways potentially needed by the rotavirus infection process. Evidence is provided here that rotavirus infectivity is significantly inhibited by NAC in different cell-culture systems. These findings suggest that NAC has the potential to be used as a therapeutic tool for treatment and prevention of rotavirus disease in children.

HIV-1, reactive oxygen species, and vascular complications

Over 1 million people in the United States and 33 million individuals worldwide suffer from HIV/AIDS. Since its discovery, HIV/AIDS has been associated with an increased susceptibility to opportunistic infection due to immune dysfunction. Highly active antiretroviral therapies restore immune function and, as a result, people infected with HIV-1 are living longer. This improved survival of HIV-1 patients has revealed a previously unrecognized risk of developing vascular complications, such as atherosclerosis and pulmonary hypertension. The mechanisms underlying these HIV-associated vascular disorders are poorly understood. However, HIV-induced elevations in reactive oxygen species (ROS), including superoxide and hydrogen peroxide, may contribute to vascular disease development and progression by altering cell function and redox-sensitive signaling pathways. In this review, we summarize the clinical and experimental evidence demonstrating HIV- and HIV antiretroviral therapy-induced alterations in reactive oxygen species and how these effects are likely to contribute to vascular dysfunction and disease.

N-acetylcysteine reverses cardiac myocyte dysfunction in HIV-Tat proteinopathy

HIV cardiomyopathy remains highly prevalent among the estimated 33 million HIV-infected individuals worldwide. This is particularly true in developing countries. Potential mechanisms responsible for myocardial dysfunction following HIV infection include direct effects of HIV proteins. We have previously reported that cardiac myocyte-specific expression of HIV-Tat (Tat) results in a murine cardiomyopathy model. We now report that Tat exhibits decreased myocardial ATP [wild type (WT) vs. Tat transgenic (TG), P < 0.01] and myocyte GSH levels (WT vs. TG, P < 0.01), decreased GSH/GSSG ratio (WT vs. TG, P < 0.01), increased H(2)O(2) levels (WT vs. TG, P < 0.05), and increased catalase (TG vs. WT, P < 0.05) and GPX1 (glutathione peroxidase 1) activities (WT vs. TG, P < 0.05), blunted cardiac myocyte positive inotropy (% peak shortening, WT vs. TG, P < 0.01; +dl/dt, WT vs. TG, P < 0.01) and negative inotropy (-dl/dt, WT vs. TG, P < 0.01), and blunted inotropic responses to Ca(2+) (P < 0.01, for each) and shortened anatomical and functional survival in vitro (P < 0.01). The sulfhydryl donor, N-acetylcysteine (NAC; 10(-4) M), completely reversed both the positive and negative inotropic defects in Tat; increased GSH (P < 0.01) and GSH/GSSG (P < 0.01); reversed H(2)O(2) level (P < 0.05) and GPX1 activity (P < 0.05); and normalized the blunted inotropic response to Ca(2+) (P < 0.01). NAC (10(-7)) M normalized duration of contractile function from <40 min to >120 min (P < 0.01), with no effect on GSH and GSH/GSSG. NAC (10(-4) M) reverses cardiac myocyte dysfunction and markers of oxidative stress. NAC (10(-7) M) enhances myocyte function independent of changes in glutathione. Elucidating the molecular mechanisms involved in the GSH-dependent and GSH-independent salutary effects of NAC should identify novel therapeutic targets for myocardial proteinopathies recently appreciated in human cardiomyopathies.

Obesity, longevity, quality of life: alteration by dietary 2-mercaptoethanol

Previous investigations demonstrated that optimization of murine immunological reactivity in tissue culture required a sulfhydryl compound; the most effective being 2-mercaptoethanol (2-Me). Since these reports, 2-Me was found beneficial for both growth/function of other cell-types in vitro, including those of other species, and when fed orally, it impeded and/or reversed some in situ physiological changes associated with aging. More recently, thiol-containing compounds possessing oxidation-reduction potentials weaker than 2-Me were found to impart beneficial effects for many other, including human, diseases. Based on these effects, the research herein addressed the question: What consequences might dietary 2-Me impart on health and disease of mice other than those associated with aging? The main parameters monitored over the lifetime of individual animals exposed to dietary 10⁻³ M 2-Me in their drinking water were: quality of life (obesity and development of recumbent, emaciated and/or cachectic health); longevity; and appearance of tumors. Instead of anticipated toxic attributes, the following unique benefits were found; mean survival of a moderately-lived strain (A/J) was increased 40.8%, high-fat-diet obesity was curtailed in C57BL/10 mice, and a goal of aging intervention protocols, namely preventing loss of quality of life during aging (recumbent, emaciated and/or cachectic) was achieved. Various mechanisms are discussed as they pertain to these findings.

Antiretroviral activity of the aminothiol WR1065 against Human Immunodeficiency virus (HIV-1) in vitro and Simian Immunodeficiency virus (SIV) ex vivo

Background

WR1065 is the free-thiol metabolite of the cytoprotective aminothiol amifostine, which is used clinically at very high doses to protect patients against toxicity induced by radiation and chemotherapy. In an earlier study we briefly reported that the aminothiol WR1065 also inhibits HIV-1 replication in phytohemagglutinin (PHA)-stimulated human T-cell blasts (TCBs) infected in culture for 2 hr before WR1065 exposure. In this study we expanded the original observations to define the dose-response curve for that inhibition, and address the question of additive effects for the combination of WR1065 plus Zidovudine (AZT). Here we also explored the effect of WR1065 on SIV by examining TCBs taken from macaques with well-established infections several months with SIV.

Results

TCBs from healthy human donors were infected for 2 hr with HIV-1, and viral replication (p24) was measured after 72 hr of incubation with or without WR1065, AZT, or both drugs. HIV-1 replication, in HIV-1-infected human TCBs, was inhibited by 50% at 13 μM WR1065, a dose at which 80% of the cells were viable. Cell cycle parameters were the same or equivalent at 0, 9.5 and 18.7 μM WR1065, showing no drug-related toxicity. Combination of AZT with WR1065 showed that AZT retained antiretroviral potency in the presence of WR1065. Cultured CD8⁺ T cell-depleted PHA-stimulated TCBs from Macaca mulatta monkeys chronically infected with SIV were incubated 17 days with WR1065, and viral replication (p27) and cell viability were determined. Complete inhibition (100%) of SIV replication (p27) was observed when TCBs from 3 monkeys were incubated for 17 days with 18.7 μM WR1065. A lower dose, 9.5 μM WR1065, completely inhibited SIV replication in 2 of the 3 monkeys, but cells from the third macaque, with the highest viral titer, only responded at the high WR1065 dose.

Conclusion

The study demonstrates that WR1065 and the parent drug amifostine, the FDA-approved drug Ethyol, have antiretroviral activity. WR1065 was active against both an acute infection of HIV-1 and a chronic infection of SIV. The data suggest that the non-toxic drug amifostine may be a useful antiretroviral agent given either alone or in combination with other drugs as adjuvant therapy.

Evidence of toxicity, oxidative stress, and neuronal insult in autism

According to the Autism Society of America, autism is now considered to be an epidemic. The increase in the rate of autism revealed by epidemiological studies and government reports implicates the importance of external or environmental factors that may be changing. This article discusses the evidence for the case that some children with autism may become autistic from neuronal cell death or brain damage sometime after birth as result of insult; and addresses the hypotheses that toxicity and oxidative stress may be a cause of neuronal insult in autism. The article first describes the Purkinje cell loss found in autism, Purkinje cell physiology and vulnerability, and the evidence for postnatal cell loss. Second, the article describes the increased brain volume in autism and how it may be related to the Purkinje cell loss. Third, the evidence for toxicity and oxidative stress is covered and the possible involvement of glutathione is discussed. Finally, the article discusses what may be happening over the course of development and the multiple factors that may interplay and make these children more vulnerable to toxicity, oxidative stress, and neuronal insult.

L-methionine as immune supportive supplement: a clinical evaluation

The objective of the study was to test L-methioinine as a possible immune supportive supplement in HIV infected patients by means of a clinical study. A double-blind, placebo-controlled study was designed. The patients (n = 253) from four different trial centres were randomly divided into two groups, active and placebo, and regularly assessed by clinical and safety parameters. After six months from commencement, clinically and statistically significant differences were observed. The females of the active treatment group presented with a decreased level of decline in their CD4 counts (p = 0.0027), so also the patients of Centre 1 (p = 0.0377). All patients were placed onto active treatment after 12 months and were followed up for 48 months after the trial started. The same tendencies could be observed in the group as a whole, with no serious side effects directly associated to treatment. The study confirmed the supportive role of L-methionine in immune-compromised or deficient patients.

HIV-dementia, Tat-induced oxidative stress, and antioxidant therapeutic considerations

Oxidative stress is thought to play a role in the onset of dementia. HIV-dementia has recently been demonstrated to be associated with oxidative stress as indexed by increased protein and lipid peroxidation in the brain and cerebrospinal fluid compared to HIV non-demented patients. The HIV protein Tat induces neurotoxicity, and, more recently, Tat was found to induce oxidative stress directly and indirectly. The role of Tat in HIV-dementia and possible therapeutic strategies involving endogenous and exogenous antioxidants are discussed.

Redox imbalance and its control in HIV infection

Human immunodeficiency virus (HIV)-infected individuals are suffering from systemic oxidative stress. Reactive oxygen species act as second messengers for the activation of nuclear factor-kappaB (NF-kappaB), which augments the replication of HIV. Intracellular levels of glutathione (GSH), a major cytosolic antioxidant, in T cells decrease during the disease progression. Another redox-regulating molecule, thioredoxin (TRX), is also transiently down-regulated in the cells by acute HIV infection. In contrast, plasma levels of TRX are elevated in the late stage of HIV infection. Intracellular GSH and plasma TRX can be biomarkers to predict the prognosis of the disease. N-Acetylcysteine (NAC), a prodrug of cysteine that is necessary for GSH synthesis, has been used for HIV infection to prevent the activation of NF-kappaB and the replication of HIV. NAC shows some beneficial effects for HIV-infected individuals, although the intracellular GSH levels in lymphocytes are not significantly restored. The control of imbalanced redox status by antioxidants may be beneficial for the quality of life in HIV infection even in the era after the effective therapy with protease inhibitors has been applied. Redox control will be an important therapeutic strategy for oxidative stress-associated disorders including HIV infection.

Polyphenolic antioxidant (-)-epigallocatechin-3-gallate from green tea as a candidate anti-HIV agent

Epigallocatechin-3-gallate (EGCG), one of the components of green tea, has been suggested to have antiviral activity. To determine the effects of EGCG on HIV infection, peripheral blood lymphocytes were incubated with either LAI/IIIB or Bal HIV strains and increasing concentrations of EGCG. EGCG strongly inhibited the replication of both virus strains as determined by reverse transcriptase and p24 assays on the cell supernatants.

NAC/MEA conjugate: a new potent antioxidant which increases the GSH level in various cell lines

I-152 is a prodrug of NAC and MEA with potent pro-GSH effects in human macrophages, astrocytes and lymphocytes. This molecule could be of interest in HIV infection in respect to its antioxidant and anti-HIV activities, but also in other diseases to counteract oxidative stress, that is, inflammation, cardiovascular diseases, and neurodegenerative diseases.

Additive effect of tunicamycin and dextran sulfate on the binding of monoclonal antibody to the V2 domain of the envelope glycoprotein 120 of human immunodeficiency virus type 1

Using flow cytometry or immunoprecipitation analysis in cells chronically infected with HIV-1 IIIB Supt-1, we noticed an additive effect of tunicamycin and low molecular weight dextran (LMDS) on the binding of the G3-4 monoclonal antibody to monomeric and oligomeric forms of glycoprotein 120 (gp120). The inhibition of glycosylation by tunicamycin reduced the number of monomeric and oligomeric forms of gp120. The inhibition of the binding of the G3-4 antibody to monomeric and oligomeric forms of gp120 was more pronounced in the presence of LMDS. We also found that the G3-4 antibody can not recognise the nascent polypeptide chain of the envelope glycoprotein.

Virological and immunological effects of antioxidant treatment in patients with HIV infection

BACKGROUND

Intracellular oxidative stress in CD4+ lymphocytes due to disturbed glutathione homeostasis may lead to impaired lymphocyte functions and enhanced HIV replication in patients with HIV infection, especially in those with advanced immunodeficiency. The aim of the present study was to assess whether short-term, high-dose antioxidant treatment might have effects on immunological and virological parameters in patients with HIV infection.

MATERIALS AND METHODS

In this pilot study, we examined virological and immunological effects of antioxidant combination treatment for 6 days with high doses of N-acetylcysteine (NAC) and vitamin C in 8 patients with HIV infection. The following were assayed before, during and after antioxidant treatment: HIV RNA plasma levels; numbers of CD4+, CD8+, and CD14+ leukocytes in blood; plasma thiols; intracellular glutathione redox status in CD4+ lymphocytes and CD14+ monocytes; lymphocyte proliferation; lymphocyte apoptosis and plasma levels of tumour necrosis factor (TNF)alpha; soluble TNF receptors and neopterin in plasma.

RESULTS

No significant changes in HIV RNA plasma levels or CD4+ lymphocyte counts in blood were noted during antioxidant treatment in the patient group. However, in the 5 patients with the most advanced immunodeficiency (CD4+ lymphocyte counts < 200 x 106 L(-1)), a significant rise in CD4+ lymphocyte count, a reduction in HIV RNA plasma level of 0.8 log, an enhanced lymphocyte proliferation and an increased level of intracellular glutathione in CD4+ lymphocytes were found. No change in lymphocyte apoptosis was noted.

CONCLUSIONS

Short-term, high-dose combination treatment with NAC and vitamin C in patients with HIV infection and advanced immunodeficiency lead to immunological and virological effects that might be of therapeutic value.

Chloroquine exerts an additive in vitro anti-HIV type 1 effect when associated with didanosine and hydroxyurea

Several groups, including ours, have reported that chloroquine (CQ) or its analog hydroxychloroquine has anti-HIV-1 activity both in vitro and in vivo. We studied in vitro whether the addition of CQ to the combination of hydroxyurea (HU) plus didanosine (ddI) had an additive effect in inhibiting the replication of HIV-1. Therefore both the H-9 T lymphocytic cell line and the U-937 promonocytic cell line as well as primary T cells and monocytes were infected with HIV-1 and then treated with HU at 0.2 mM and ddI at 1 microM and varying concentrations of CQ. Addition of CQ resulted in an additional inhibition of HIV-1 replication, as assessed by reverse transcriptase (RT) activity, with a CQ EC50 of 0.4-0.9 microM for the cell lines and of 0.2-0.9 microM for the primary cells. Similarly, addition of CQ further inhibited HIV-1 replication in U-1 cells stimulated either with LPS or H2O2 and in ACH-2 cells stimulated either with PMA or H2O2, with CQ EC50 values of 0.1 and 1 microM, respectively. Under the experimental conditions used, CQ induced neither toxicity nor apoptosis in the H-9 and U-937 cells. This in vitro additive anti-HIV-1 activity of CQ, in combination with HU + ddI, supports the idea that this triple regimen should be studied in clinical trials. It may become of particular interest to HIV-1-infected individuals from the developing world, in view of the low cost of both CQ and HU.

A simple colorimetric method for the simultaneous determination of N-acetylcysteine and cysteine

The widespread use of N-acetylcysteine as an antioxidant and a precursor for tissue cysteine creates a need for a simple method that measures both and distinguishes them from one another. We describe a procedure based on the use of the enzyme acylase, which hydrolyzes N-acetylcysteine to cysteine. Cysteine is subsequently measured with a specific colorimetric procedure. Unhydrolyzed N-acetylcysteine gives only a weak colorimetric response (11.5% that for cysteine); after hydrolysis, however, the two are equivalent. Hence, N-acetylcysteine can be distinguished by the enhanced response after hydrolysis.

Antioxidant defenses influence HIV-1 replication and associated cytopathic effects

HIV-infected cells often exhibit reduced levels of antioxidant enzymes and thiols. To investigate the role of cellular antioxidant defenses in the progression of an acutely spreading HIV-1 infection, human Sup-T1 T cells were engineered to overexpress the selenium-dependent glutathione peroxidase, GSHPx-1. This enzyme represents a major cellular defense mechanism against toxicity associated with reactive oxygen species (ROS). T cells engineered to produce elevated GSHPx-1 activity displayed accelerated viral replication and associated cytopathic effects compared to control cells. Conversely, the inhibition of the synthesis of glutathione with buthione sulfoximine (BSO) resulted in the attenuation of viral replication in Sup-T1 cells. Similarly, exposure of human peripheral blood lymphocytes (PBLs) to low, nontoxic levels of BSO resulted in an approximately 80% decline in HIV-1 replication as indicated by Western blot analysis of viral proteins.

Sodium selenite and N-acetylcysteine in antiretroviral-naive HIV-1-infected patients: a randomized, controlled pilot study

BACKGROUND

The aim of this work was to study the effects of combined oral administration of N-acetylcysteine (NAC) and sodium selenite (Se) on plasma glutathione (GSH), lymphocyte subpopulations and viral load in asymptomatic human immunodeficiency virus (HIV)-infected patients.

METHODS

We used a prospective, randomized and controlled therapy trial with partial crossover. Twenty-four antiretroviral-naive HIV-infected outpatients at Centers for Disease Control (CDC)'93 stages I and II were randomized to receive the antioxidant combination NAC 600 mg t.i.d. and Se 500 micrograms per day for either 24 weeks (group A, n = 13) or from the end of week 12 (group B, n = 11) until the end of week 24. Thus, group B served as untreated control during the first 12 weeks.

RESULTS

There was (a) a trend towards an increase in the percentage of CD4+ lymphocytes after 6 weeks (P = 0.08); (b) an increase in the CD4/CD8 ratio after 6 and 12 weeks (P = 0.02 and P = 0.04 respectively); and (c) a decrease in the absolute CD8/CD38 count and percentage of lymphocytes after 6 weeks (P = 0.002 and P = 0.033 respectively) and 12 weeks (P = 0.033, P = 0.1 respectively) in group A compared with the control period of group B. The effects observed in group A were, however, not paralleled to the same extent by group B after crossing-over to treatment after 12 weeks. In addition, erythrocyte glutathione peroxidase (GSH-Px) activity and GSH, glutathionedisulphide (GSSG) concentrations and the reduced/total GSH ratio were not affected by the treatment. Serum selenium levels increased significantly (P < 0.001) upon treatment. Viral load was not altered.

CONCLUSIONS

The changes in lymphocyte subsets after NAC/Se treatment were not comparable to those after standard antiretroviral drug therapy. This, however, does not preclude per se possible benefits of antioxidant supplementation in HIV disease.

Secretion of extracellular factor(s) induced by X-irradiation activates the HIV type 1 long terminal repeat through its kappaB motif

X-irradiation has been used in the treatment of several human diseases, including AIDS-related-malignancies. X-irradiation might induce the transcription and the replication of human immunodeficiency virus type 1 (HIV-1) and enhance nuclear factor kappa B (NF-kappaB). In the present article we show that the activation of the HIV-1 long terminal repeat (LTR) by direct X-irradiation can be mimicked by coculture of transfected cells with X-irradiated nontransfected (HIV-1-negative) cells. In the human colonic carcinoma cell line HT29, the activation seems to depend on an extracellular factor(s) released by a cell line treated with X-rays. The HIV-1 LTR cis-acting element conferring X-indirect responsiveness was identified as the kappaB tandem motif. The two main nuclear HIV-1 kappaB-binding complexes activated by X-direct and -indirect irradiation were the NF-kappaB p50/p65 and c-Rel/p65 heterodimers. Nuclear NF-kappaB activation was dependent on protein neosynthesis. It was partially inhibited by 100 microM pyrrolidine dithiocarbamate, a potent antioxidant drug, but was not correlated with a significant decrease in cellular IkappaBalpha. Furthermore, X-irradiation induces the expression of several cytokine genes generally associated with stress response and antibodies against interleukin 6 and TNF-alpha partially inhibited the X-indirect activation of the HIV-1 LTR. The use of protein kinase C (PKC)-specific inhibitor and of forskolin, an adenylate cyclase activator, suggests that a PKC-dependent pathway and the cAMP intracellular concentration could play a role in the X-indirect enhancement of HIV-1 LTR transcription in the HT29 cell line. In addition, supernatants of an X-irradiated HT29 cell culture activated the HIV-1 stimulation in infected peripheral blood monocytes.

Selenium supplementation suppresses tumor necrosis factor alpha-induced human immunodeficiency virus type 1 replication in vitro

Selenium is a nutritionally essential trace element that is important for optimal function of the immune system. It is incorporated into selenoproteins as the amino acid selenocysteine and it is known to inhibit the expression of some viruses. In this study, we show that selenium supplementation for 3 days prior to exposure to tumor necrosis factor alpha (TNF-alpha) partially suppresses the induction of human immunodeficiency virus type 1 (HIV-1) replication in both chronically infected T lymphocytic and monocytic cell lines. In acute HIV-1 infection of T lymphocytes and monocytes in the absence of exogenous TNF-alpha, the suppressive effect of selenium supplementation was not observed. However, selenium supplementation did suppress the enhancing effect of TNF-alpha on HIV-1 replication in vitro in acutely infected human monocytes, but not in T lymphocytes. Selenium supplementation also increased the activities of the selenoproteins, glutathione peroxidase (GPx) and thioredoxin reductase (TR), which serve as cellular antioxidants. Taken together, these results suggest that selenium supplementation may prove beneficial as an adjuvant therapy for AIDS through reinforcement of endogenous antioxidative systems.

L-2-oxothiazolidine-4-carboxylic acid inhibits human immunodeficiency virus type 1 replication in mononuclear phagocytes and lymphocytes

We investigated the effects of L-2-oxothiazolidine-4-carboxylic acid (OTC; Procysteine), a cysteine prodrug, on human immunodeficiency virus type 1 (HIV-1) expression in both adult peripheral and cord blood mononuclear phagocytes and lymphocytes. OTC suppressed HIV-1 expression in monocyte-derived macrophages (MDM) and lymphocytes in a dose-dependent fashion as determined by HIV-1 reverse transcriptase (RT) activity. This inhibitory effect of OTC occurred with three HIV-1 strains (two laboratory-adapted strains and one primary isolate). Addition of OTC to chronically HIV-1-infected MDM cultures also suppressed RT activity by 40 to 50% in comparison to untreated controls. The inhibitory effects of OTC on HIV-1 were not caused by toxicity to MDM or lymphocytes because there was no change in cell viability or cellular DNA synthesis, as evaluated by trypan blue dye exclusion and [3H]thymidine incorporation, at doses of OTC that inhibit virus replication. These observations indicate that OTC has the potential to limit HIV-1 replication in mononuclear phagocytes and lymphocytes and may be useful in the treatment of HIV-1 infection and AIDS.

Regulation of cellular thiols in human lymphocytes by alpha-lipoic acid: a flow cytometric analysis

Modulation of cellular thiols is an effective therapeutic strategy, particularly in the treatment of AIDS. Lipoic acid, a metabolic antioxidant, functions as a redox modulator and has proven clinically beneficial effects. It is also used as a dietary supplement. We utilized the specific capabilities of N-ethylmaleimide to block total cellular thiols, phenylarsine oxide to block vicinal dithiols, and buthionine sulfoximine to deplete cellular GSH to flow cytometrically investigate how these thiol pools are influenced by exogenous lipoate treatment. Low concentrations of lipoate and its analogue lipoamide increased Jurkat cell GSH in a dose-dependent manner between 10 (25 microM for lipoamide) to 100 microM. This was also observed in mitogenically stimulated peripheral blood lymphocytes (PBL). Studies with Jurkat cells and its Wurzburg subclone showed that lipoate dependent increase in cellular GSH was similar in CD4+ and - cells. Chronic (16 week) exposure of cells to lipoate resulted in further increase of total cellular thiols, vicinal dithiols, and GSH. High concentration (2 and 5 mM) of lipoate exhibited cell shrinkage, thiol depletion, and DNA fragmentation effects. Based on similar effects of octanoic acid, the cytotoxic effects of lipoate at high concentration could be attributed to its fatty acid structure. In certain diseases such as AIDS and cancer, elevated plasma glutamate lowers cellular GSH by inhibiting cystine uptake. Low concentrations of lipoate and lipoamide were able to bypass the adverse effect of elevated extracellular glutamate. A heterogeneity in the thiol status of PBL was observed. Lipoate, lipoamide, or N-acetylcysteine corrected the deficient thiol status of cell subpopulations. Hence, the favorable effects of low concentrations of lipoate treatment appears clinically relevant.

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.

Impact of oxidative stress on human cytomegalovirus replication and on cytokine-mediated stimulation of endothelial cells

Transplantation-related pathogenic factors such as ischemia or allograft-directed inflammation are associated with oxidative changes that might lead to cellular oxidative stress. The aim of this study was to investigate the impact of oxidative stress on: (1) CMV replication in cultured human endothelial cells and (2) the stimulation of endothelial cells by proinfiammatory cytokines. Both pathomechanisms are known to contribute to graft rejection crises in vivo. Oxidative stress was induced in endothelial cell cultures with 10-200 microM buthionine sulfoximine. Western blotting showed a significant increase in the production of CMV-specific immediate early and late proteins in buthionine sulfoximine-treated cultures. Immunocytochemical staining suggested that this effect was caused by increased numbers of CMV antigen expressing cells (66% immediate early; 78%, late). Quantitative polymerase chain reaction for CMV-specific DNA and virus titration revealed that enhanced viral replication levels correlated with increased virion production. As a measure for the endothelial cell activation status, the surface expression of HLA-ABC and HLA-DR and adhesion molecules (ICAM-1, ELAM-1, VCAM-1) was quantified by fluorometric methods. Whereas oxidative stress alone did not modulate any surface molecule expression, the IFN-gamma-mediated expression of HLA-ABC and HLA-DR and the IL-1-mediated expression of ICAM-1, but not of ELAM-1 and VCAM-1 (IL-1 + TNF-alpha), was amplified. Interestingly, the amplification of HLA molecule expression was even higher in CMV-infected endothelial cells. This study provides evidence that oxidative stress contributes to the regulation of CMV replication, virus shedding, and the activation of endothelial cells by proinflammatory cytokines as it is observed in transplant recipients.

Iron chelation decreases NF-kappa B and HIV type 1 activation due to oxidative stress

An important aspect of human immunodeficiency virus (HIV-1) infection is the regulation of its expression by nuclear factor kappa B (NF-kappa B) through redox-controlled signal transduction pathways. In this study, we demonstrate that iron chelation by deferoxamine (DFO) protects against the cytotoxic and reactivating effects of hydrogen peroxide (H2O2). These protective effects were observed both in lymphocytic (ACH-2) and promonocytic (U1) cells latently infected by HIV-1. Concomitantly, NF-kappa B activation by H2O2, when followed by gel retardation assay, was decreased in the DFO-treated U1 and ACH-2 cells. This latter DFO-mediated effect was specific, as DFO did not clearly affect AP-1 DNA-binding activity when studied after H2O2-induced stress. More importantly, DFO protected against the H2O2-induced activation of HIV-1 as evidenced by reverse transcriptase activity in the supernatant. DFO also protected against PMA-induced NF-kappa B activation as well as TNF-alpha-induced HIV-1 activation. Furthermore, DFO attenuated the p24 response in PBMC infected with HIV-1 and stimulated with IL-2. These different effects of DFO were obtained at DFO concentrations lower than 5 microM. Other chemically unrelated iron chelators also provided protection against cytotoxicity, NF-kappa B activation, and HIV-1 activation in U1 cells challenged with H2O2.

Cystamine inhibits HIV type 1 replication in cells of monocyte/macrophage and T cell lineages

The effects of cysteamine (2-aminoethanethiol, MEA) and its disulfide, cystamine, on the human immunodeficiency virus (HIV-1) expression in chronically infected promonocytic cells (U1), T cell line (ACH-2), and peripheral blood monocyte-derived macrophages (MDM) were investigated. U1 and ACH-2 cells constitutively express low levels of virus, which is increased by the addition of tumor necrosis factor (TNF-alpha), interleukin 6 (IL-6), granulocyte-macrophage-colony-stimulating factor (GM-CSF), and other inducers. Cystamine, in noncytotoxic doses, suppressed in a concentration-dependent fashion the induction of HIV-1 expression mediated by TNF-alpha, IL-6, GM-CSF, and monokine-enriched monocyte culture supernatants in both U1 and ACH-2 cells as determined by HIV-1 reverse transcriptase (RT) activity. Similarly, HIV-1 expression was substantially reduced in the cystamine-treated primary MDM cultures compared with the untreated control cultures. The addition of cystamine into HIV-1 chronically infected MDM (12 days after infection was established) also suppressed 80-90% of RT activity in comparison to the untreated controls. HIV-1 (Bal) infected MDM cultures (without cystamine treatment) demonstrated giant syncytium formation, whereas cystamine-treated cultures lacked the giant syncytia induced by HIV-1 infection. Cystamine also inhibited LPS-induced TNF production in MDM. In contrast to cystamine, cysteamine showed no significant effects on either the monokine-induced HIV-1 expression in U1 or ACH-2 or acute and chronic HIV-1 infection in MDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of glutathione peroxidase activity decreases HIV type 1 activation after oxidative stress

Am important aspect of human immunodeficiency virus (HIV-1) infection is the regulation of its expression by nuclear factor kappa B (NF-kappa B) by redox-controlled signal transduction pathways. In this study, we demonstrate that selenium supplementation can effectively increase glutathione peroxidase (GPx) activity in latently infected T lymphocytes. The Se-supplemented cells exhibited an important protection against the cytotoxic and reactivating effects of hydrogen peroxide (H2O2). Concomitantly, NF-kappa B activation by H2O2 was also decreased in Se-supplemented cells. Selenium stimulation of GPx activity also induces a protective effect against cell activation by tumor necrosis factor alpha (TNF-alpha) but less significantly by phorbol esters such as PMA. These Se-mediated effects were specific because they were not found when AP-1 DNA-binding activity was studied after H2O2-induced stress. Hyperthermia was also studied because it could promote intracellular electron leakage in electron transport chains. Elevating the temperature to 42 degrees C did not induce NF-kappa B directly. Rather, it sensitized infected cells to subsequent oxidative stress by H2O2, demonstrating the importance of hyperthermia, often associated with opportunistic infections in the development of immunodeficiency. In this case, Se induced partial protection against the sensitizing effect of hyperthermia.

Oltipraz, an inhibitor of human immunodeficiency virus type 1 replication

Glutathione depletion may play a pivotal role in the pathogenesis of human immunodeficiency virus type-1 (HIV-1) infection. Since certain compounds prevent experimental carcinogenesis by elevating the levels of glutathione and phase II detoxication enzymes, we compared the potencies of several inducers with their ability to inhibit basal levels of HIV-1 replication in H9 cutaneous T-cell lymphoma cells. All monofunctional inducers tested elevated the levels of glutathione and quinone reductase, a marker for phase II enzyme induction. However, only oltipraz [4-methyl-5-(2-pyrazinyl)-1,2-dithiole-3-thione] was effective at inhibiting HIV-1 replication (IC50 = 14.8 +/- 3.1 microM). The antiviral effect of oltipraz was potentiated by 3'-azido-3'-deoxythymidine. Thus, 1,2-dithiole-3-thiones represent a hitherto unrecognized class of anti-HIV-1 agents. Oltipraz behaves kinetically as an irreversible inhibitor of HIV-1 reverse transcriptase in the template-primer binding domain. Oltipraz has been used to treat schistosomiasis in humans and is undergoing clinical evaluation as an anticarcinogen. Thus, oltipraz (and other 1,2-dithiole-3-thiones) may have therapeutic utility in HIV-1-infected individuals, not only because of their antiretroviral activity, but also by preventing the development of HIV-1-associated neoplasms.

Thiol suppression of human immunodeficiency virus type 1 replication in primary cord blood monocyte-derived macrophages in vitro

We investigated the effects of glutathione (GSH), the major naturally occurring thiol, and a pharmacologic thiol precursor of GSH, N-acetyl cysteine (NAC), on the expression of human immunodeficiency type 1 (HIV-1) in primary cord blood and adult donor monocyte-derived macrophages (MDM). HIV-1 infection of cord blood and adult MDM was accomplished after incubating 10-15-d-old cultures for 4 h with a monocyte-tropic strain of HIV-1 (Bal). After 1 wk in culture cell supernatants were tested for reverse transcriptase (RT) activity. MDM were exposed to 5, 10 and 20 mM concentrations of both GSH and NAC before infection, during infection, and after infection was established. GSH and NAC suppressed the replication of HIV-1 in both primary cord blood and adult donor MDM in a concentration dependent fashion. These suppressive effects were more pronounced in cord-derived cells than in adult-derived cells. In cells treated with GSH or NAC before infection, there was no significant rise in RT activity as compared with controls. Similarly, when cells were treated with GSH and NAC and simultaneously infected, there was also no significant rise in RT activity after 1 wk in culture. In cells treated after infection was established, RT values were suppressed 80-90% that of untreated controls. This effect persisted for 1-2 wk after exposure to GSH and NAC. Untreated controls demonstrated syncytium formation and lost characteristics of spreading and elongation 2 wk after HIV-1 infection, whereas most of the treated cells remained free of syncytium and retained cytoplasmic spreading, adherence, and elongation. These data are consistent with other studies of thiol suppression of HIV-1 replication and demonstrate a similar observation for primary cultured cord MDM. These results may offer new approaches toward cellular protection after infection with HIV-1.