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

One advantageous reflection of iron metabolism in context of normal physiology and pathological phases

PURPOSE (BACKGROUND)

The presented review is an updating of Iron metabolism in context of normal physiology and pathological phases. Iron is one of the vital elements in humans and associated into proteins as a component of heme (e.g. hemoglobin, myoglobin, cytochromes proteins, myeloperoxidase, nitric oxide synthetases), iron sulfur clusters (e.g. respiratory complexes I-III, coenzyme Q10, mitochondrial aconitase, DNA primase), or other functional groups (e.g. hypoxia inducible factor prolyl hydroxylases). All these entire iron-containing proteins ar e needed for vital cellular and organismal functions together with oxygen transport, mitochondrial respiration, intermediary and xenobiotic metabolism, nucleic acid replication and repair, host defense, and cell signaling.

METHODS (METABOLIC STRATEGIES)

Cells have developed metabolic strategies to import and employ iron safely. Regulatory process of iron uptake, storage, intracellular trafficking and utilization is vital for the maintenance of cellular iron homeostasis. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. The predominant organs, which are associated in the metabolism of iron, are intestine, liver, bone marrow and spleen. Iron is conserved, recycled and stored. The reduced bioavailability of iron in humans has developed extremely efficient mechanisms for iron conservation. Prominently, the losses of iron cannot considerably enhance through physiologic mechanisms, even if iron intake and stores become excessive. Loss of iron is balanced or maintained from dietary sources.

RESULTS (OUTCOMES)

Numerous physiological abnormalities are associated with impaired iron metabolism. These abnormalities are appeared in the form of several diseases. There are duodenal ulcer, inflammatory bowel disease, sideroblastic anaemia, congenital dyserythropoietic anemias and low-grade myelodysplastic syndromes. Hereditary hemochromatosis and anaemia are two chronic diseases, which are responsible for disturbing the iron metabolism in various tissues, including the spleen and the intestine. Impairment in hepatic hepcidin synthesis is responsible for chronic liver disease, which is grounding from alcoholism or viral hepatitis. This condition directs to iron overload that can cause further hepatic damage. Iron has important role in several infectious diseases are tuberculosis, malaria trypanosomatid diseases and acquired immunodeficiency syndrome (AIDS). Iron is also associated with Systemic lupus erythematosus [SLE], cancer, Alzheimer's disease (AD) and post-traumatic epilepsy.

CONCLUSION

Recently, numerous research studies are gradually more dedicated in the field of iron metabolism, but a number of burning questions are still waiting for answer. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. Increased information of the physiology of iron homeostasis will support considerate of the pathology of iron disorders and also make available the support to advance treatment.

Infection metallomics for critical care in the post-COVID era

Infection metallomics is a mass spectrometry (MS) platform we established based on the central concept that microbial metallophores are specific, sensitive, noninvasive, and promising biomarkers of invasive infectious diseases. Here we review the in vitro, in vivo, and clinical applications of metallophores from historical and functional perspectives, and identify under-studied and emerging application areas with high diagnostic potential for the post-COVID era. MS with isotope data filtering is fundamental to infection metallomics; it has been used to study the interplay between "frenemies" in hosts and to monitor the dynamic response of the microbiome to antibiotic and antimycotic therapies. During infection in critically ill patients, the hostile environment of the host's body activates secondary bacterial, mycobacterial, and fungal metabolism, leading to the production of metallophores that increase the pathogen's chance of survival in the host. MS can reveal the structures, stability, and threshold concentrations of these metal-containing microbial biomarkers of infection in humans and model organisms, and can discriminate invasive disease from benign colonization based on well-defined thresholds distinguishing proliferation from the colonization steady state.

Functionalized gold nanoparticles: promising and efficient diagnostic and therapeutic tools for HIV/AIDS

Functionalized gold nanoparticles are recognized as promising vehicles in the diagnosis and treatment of human immunodeficiency virus (HIV) owing to their excellent biocompatibility with biomolecules (like DNA or RNA), their potential for multivalency and their unique optical and structural properties. In this context, this review article focuses on the diverse detection abilities and delivery and uptake methodologies of HIV by targeting genes and proteins using gold nanoparticles on the basis of different shapes and sizes in order to promote its effective expression. In addition, recent trends in gold nanoparticle mediated HIV detection, delivery and uptake and treatment are highlighted considering their cytotoxic effects on healthy human cells.

Hydroxypyridinone-Based Iron Chelators with Broad-Ranging Biological Activities

Iron plays an essential role in all living cells because of its unique chemical properties. It is also the most abundant trace element in mammals. However, when iron is present in excess or inappropriately located, it becomes toxic. Excess iron can become involved in free radical formation, resulting in oxidative stress and cellular damage. Iron chelators are used to treat serious pathological disorders associated with systemic iron overload. Hydroxypyridinones stand out for their outstanding chelation properties, including high selectivity for Fe³⁺ in the biological environment, ease of derivatization, and good biocompatibility. Herein, we overview the potential for multifunctional hydroxypyridinone-based chelators to be used as therapeutic agents against a wide range of diseases associated either with systemic or local elevated iron levels.

Iron Pathways and Iron Chelation Approaches in Viral, Microbial, and Fungal Infections

Iron is an essential element required to support the health of organisms. This element is critical for regulating the activities of cellular enzymes including those involved in cellular metabolism and DNA replication. Mechanisms that underlie the tight control of iron levels are crucial in mediating the interaction between microorganisms and their host and hence, the spread of infection. Microorganisms including viruses, bacteria, and fungi have differing iron acquisition/utilization mechanisms to support their ability to acquire/use iron (e.g., from free iron and heme). These pathways of iron uptake are associated with promoting their growth and virulence and consequently, their pathogenicity. Thus, controlling microorganismal survival by limiting iron availability may prove feasible through the use of agents targeting their iron uptake pathways and/or use of iron chelators as a means to hinder development of infections. This review will serve to assimilate findings regarding iron and the pathogenicity of specific microorganisms, and furthermore, find whether treating infections mediated by such organisms via iron chelation approaches may have potential clinical benefit.

Iron overload down-regulates the expression of the HIV-1 Rev cofactor eIF5A in infected T lymphocytes

BACKGROUND

Changes in iron metabolism frequently accompany HIV-1 infection. However, while many clinical and in vitro studies report iron overload exacerbates the development of infection, many others have found no correlation. Therefore, the multi-faceted role of iron in HIV-1 infection remains enigmatic.

METHODS

RT-qPCR targeting the LTR region, gag, Tat and Rev were performed to measure the levels of viral RNAs in response to iron overload. Spike-in SILAC proteomics comparing i) iron-treated, ii) HIV-1-infected and iii) HIV-1-infected/iron treated T lymphocytes was performed to define modifications in the host cell proteome. Data from quantitative proteomics were integrated with the HIV-1 Human Interaction Database for assessing any viral cofactors modulated by iron overload in infected T lymphocytes.

RESULTS

Here, we demonstrate that the iron overload down-regulates HIV-1 gene expression by decreasing the levels of viral RNAs. In addition, we found that iron overload modulates the expression of many viral cofactors. Among them, the downregulation of the REV cofactor eIF5A may correlate with the iron-induced inhibition of HIV-1 gene expression. Therefore, we demonstrated that eiF5A downregulation by shRNA resulted in a significant decrease of Nef levels, thus hampering HIV-1 replication.

CONCLUSIONS

Our study indicates that HIV-1 cofactors influenced by iron metabolism represent potential targets for antiretroviral therapy and suggests eIF5A as a selective target for drug development.

Mutual interaction between iron homeostasis and obesity pathogenesis

Obesity is identified as an important medical problem. One of the pathologic conditions observed in obesity is systemic iron deficiency and hypoferremia. Along with a large number of studies indicating disturbed iron homeostasis in obesity, recent data indicate a cause-effect relationship between iron status and obesity-related pathologies. The primary objective of the article is to consider two aspects of the iron-obesity interplay: (1) the mechanisms leading to impaired iron balance, and (2) the pathways of iron participation in obesity-related pathogenesis. While considering disturbance of iron homeostasis in obesity, a number of potential mechanisms of hypoferremia are proposed. At the same time, the inflammation of obesity and obesity-related hepcidin and lipocalin 2 hyperproduction seem to be the most probable reasons of obesity-related hypoferremia. Oversecretion of these proteins leads to iron sequestration in reticuloendothelial system cells. The latter also leads to increased adipose tissue iron content, thus producing preconditions for adverse effects of local iron overload. Being a redox-active metal, iron is capable of inducing oxidative stress as well as endoplasmic reticulum stress, inflammation and adipose tissue endocrine dysfunction. Iron-mediated mechanisms of toxicity may influence aspects of obesity pathogenesis possibly even leading to obesity aggravation. Thus, a mutual interaction between disturbance in iron homeostasis and obesity pathogenesis is proposed. All sides of this interaction should be considered to design new therapeutic approaches to the treatment of disturbed iron homeostasis in obesity.

Short communication: high cellular iron levels are associated with increased HIV infection and replication

HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4(+) T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV.

Serum hepcidin levels in women infected with HIV-1 under antiviral therapy

Accumulating data suggest that iron may have a role in the regulation of HIV-infection. In the present study, we determined by radioimmunoassay the levels of hepcidin, a key regulator of iron homeostasis, in sera of 182 women infected with HIV-1 under highly active antiretroviral therapy (HAART). In the total cohort, hepcidin levels were lower in individuals infected with HIV than in controls (3.20 ± 3.06 vs. 5.68 ± 3.66 nmol/L, P = 0.009). Serum hepcidin concentrations were strongly correlated positively with iron, ferritin, urea, and uric acid. In the total cohort of patients with abnormal viral load and CD4 cell count <500 cells/mm(3) , a strong positive correlation was found between hepcidin and viral load. Hepcidin level was significantly higher in HIV-patients with high viremia than in patients with undetectable viral load. Iron level was significantly lower in HIV-patients with high viral load compared with patients with undetectable viral load. This study suggests that hepcidin controls serum iron, especially in response of iron utilization by HIV for viral replication. The possibility of using inhibitors of hepcidin expression as adjunct therapy for HIV-patients is discussed.

Inhibition of replication of porcine reproductive and respiratory syndrome virus by hemin is highly dependent on heme oxygenase-1, but independent of iron in MARC-145 cells

Current vaccines against porcine reproductive and respiratory syndrome virus (PRRSV) have failed to provide sustainable disease control, and development of new antiviral strategies is of great importance. The present study investigated the mechanism of the antiviral effect of hemin during PRRSV infection in MARC-145 cells. Hemin, a commercial preparation of heme, is used as an iron donor or heme oxygenase 1 (HO-1) inducer, and has been shown to provide antiviral activity in many studies. In the current study, the anti-PRRSV activity of hemin was identified through suppressing PRRSV propagation. The 50% inhibitory concentration (IC50) of hemin antiviral activity was estimated to be 32μM, and the 50% cytotoxic concentration (CC50) of hemin was found to be higher than 125μM. Further study showed that the antiviral activity of hemin is independent of iron. In addition, after treatment with Protoporphyrin IX zinc (II) (ZnPP) or Sn (IV) Protoporphyrin IX dichloride (SnPP), inhibitors of HO-1, the inhibition of viral replication by hemin was partially reversed. Additionally, it was confirmed that hemin and N-acetyl cysteine were able to significantly reduce reactive oxygen species (ROS) in MARC-145 cells infected with virus. N-acetyl-L-cysteine (NAC), however, did not produce a reduction in viral load or promote expression of HO-1. Taken together, these data indicate that the effect of hemin on the inhibition of PRRSV propagation via HO-1 induction, as well as the antiviral mechanism of HO-1, is not dependent on decreased levels of ROS. In conclusion, these data demonstrate that hemin had antiviral activity against PRRSV and may serve as a useful antiviral agent inhibiting PRRSV replication.

Lentiviral Nef suppresses iron uptake in a strain specific manner through inhibition of Transferrin endocytosis

BACKGROUND

Increased cellular iron levels are associated with high mortality in HIV-1 infection. Moreover iron is an important cofactor for viral replication, raising the question whether highly divergent lentiviruses actively modulate iron homeostasis. Here, we evaluated the effect on cellular iron uptake upon expression of the accessory protein Nef from different lentiviral strains.

RESULTS

Surface Transferrin receptor (TfR) levels are unaffected by Nef proteins of HIV-1 and its simian precursors but elevated in cells expressing Nefs from most other primate lentiviruses due to reduced TfR internalization. The SIV Nef-mediated reduction of TfR endocytosis is dependent on an N-terminal AP2 binding motif that is not required for downmodulation of CD4, CD28, CD3 or MHCI. Importantly, SIV Nef-induced inhibition of TfR endocytosis leads to the reduction of Transferrin uptake and intracellular iron concentration and is accompanied by attenuated lentiviral replication in macrophages.

CONCLUSION

Inhibition of Transferrin and thereby iron uptake by SIV Nef might limit viral replication in myeloid cells. Furthermore, this new SIV Nef function could represent a virus-host adaptation that evolved in natural SIV-infected monkeys.

Does venesection reduce HIV viral load in patients with hereditary haemochromatosis?

It is recognized that iron overload is associated with excess mortality in HIV/AIDS, and that this may be due to iron acting as an HIV-1 transcriptional activator. In vitro evidence using iron chelators suggests that therapeutic iron depletion may be beneficial in HIV-1 infection. We describe the clinical course of a Caucasian man with hereditary haemochromatosis and HIV infection where a significant drop in HIV viral load accompanied venesection over an 18-month period in the absence of HAART. We propose that further research should be undertaken to explore the relationship between HIV viral load and serum iron markers in hereditary haemochromatosis, with a view to evaluating the therapeutic benefit of venesection on HIV viral load in this setting.

Transferrin polymorphism and opportunistic infections in HIV-infected women in Rwanda

OBJECTIVE

We investigated the prevalence of opportunistic infections in HIV-infected women according to transferrin (TF) phenotype.

METHODS

We conducted a cross-sectional study among 200 HIV-positive women in the Butare University Teaching Hospital in Rwanda. TF phenotypes were determined using starch gel electrophoresis.

RESULTS

Phenotype frequencies of TF CD, CB and CC were 14.5, 3 and 82.5%, respectively. The homozygous TF DD phenotype was not found. Subjects with TF CD phenotype had a significantly higher prevalence of opportunistic infections than subjects with TF CC phenotype, 76 and 52%, respectively (p = 0.026). In logistic regression, there was a significant correlation between TF phenotypes and opportunistic infections (p = 0.012). Subjects with TF CD phenotype had significantly lower values for TF (p = 0.006) than TF CC subjects. Hematological parameters (RBC, RBC indices, hemoglobin, hematocrit, WBC, neutrophils, lymphocytes, platelets and erythrocyte sedimentation rate), iron, ferritin, TF saturation, C-reactive protein and CD4 count did not differ according to TF phenotype.

CONCLUSION

Subjects with TF CC phenotype have a lower prevalence of opportunistic infections. Iron status may play a role in this association.

The prevalence and etiology of anemia among HIV-infected children in India

In this report, the prevalence and multifactorial etiology of anemia among Indian human immunodeficiency virus (HIV)-infected children are described. HIV-infected children aged 2-12 years were prospectively enrolled in 2007-2008. Measured parameters included serum ferritin, vitamin B(12), red-cell folate, soluble transferrin receptor, and C-reactive protein. Children received antiretroviral therapy (ART), iron and, folate supplements as per standard of care. Among 80 enrolled HIV-infected children (mean age 6.8 years), the prevalence of anemia was 52.5%. Etiology of anemia was found to be iron deficiency alone in 38.1%, anemia of inflammation alone in 38.1%, combined iron deficiency and anemia of inflammation alone in 7.1%, vitamin B(12) deficiency in 7.1%, and others in 9.5%. Median iron intake was 5.7 mg/day (recommended dietary allowance 18-26 mg/day). Compared to nonanemic children, anemic children were more likely to be underweight (weight Z-score -2.5 vs. -1.9), stunted (height Z-score -2.6 vs. -1.9), with lower CD4 counts (18% vs. 24%, p < 0.01), and higher log viral load (11.1 vs. 7.1, p < 0.01). Hemoglobin (Hb) improved significantly among those who started ART (baseline Hb 11.6 g/dl, 6-month Hb 12.2 g/dl, p = 0.03). Children taking ART combined with iron supplements experienced a larger increase in Hb compared to those receiving neither ART nor iron supplements (mean Hb change 1.5 g/dl, p < 0.01).

CONCLUSION

Anemia, particularly iron deficiency anemia and anemia of inflammation, is highly prevalent among children with HIV infection. Micronutrient supplements combined with ART improved anemia in HIV-infected children.

Iron metabolism and the innate immune response to infection

Host antimicrobial mechanisms reduce iron availability to pathogens. Iron proteins influencing the innate immune response include hepcidin, lactoferrin, siderocalin, haptoglobin, hemopexin, Nramp1, ferroportin and the transferrin receptor. Numerous global health threats are influenced by iron status and provide examples of our growing understanding of the connections between infection and iron metabolism.

The initial step in human immunodeficiency virus type 1 GagProPol processing can be regulated by reversible oxidation

Background

Maturation of human immunodeficiency virus type 1 (HIV-1) occurs upon activation of HIV-1 protease embedded within GagProPol precursors and cleavage of Gag and GagProPol polyproteins. Although reversible oxidation can regulate mature protease activity as well as retrovirus maturation, it is possible that the effects of oxidation on viral maturation are mediated in whole, or part, through effects on the initial intramolecular cleavage event of GagProPol. In order assess the effect of reversible oxidation on this event, we developed a system to isolate the first step in protease activation involving GagProPol.

Methodology/Principal Findings

To determine if oxidation influences this step, we created a GagProPol plasmid construct (pGPfs-1C) that encoded mutations at all cleavage sites except p2/NC, the initial cleavage site in GagProPol. pGPfs-1C was used in an in vitro translation assay to observe the behavior of this initial step without interference from subsequent processing events. Diamide, a sulfhydral oxidizing agent, inhibited processing at p2/NC by >60% for pGPfs-1C and was readily reversed with the reductant, dithiothreitol. The ability to regulate processing by reversible oxidation was lost when the cysteines of the embedded protease were mutated to alanine. Unlike mature protease, which requires only oxidation of cys95 for inhibition, both cysteines of the embedded protease contributed to this inhibition.

Conclusions/Significance

We developed a system that can be used to study the first step in the cascade of HIV-1 GagProPol processing and show that reversible oxidation of cysteines of HIV-1 protease embedded in GagProPol can block this initial GagProPol autoprocessing. This type of regulation may be broadly applied to the majority of retroviruses.

Treating cofactors can reverse the expansion of a primary disease epidemic

BACKGROUND

Cofactors, "nuisance" conditions or pathogens that affect the spread of a primary disease, are likely to be the norm rather than the exception in disease dynamics. Here we present a "simplest possible" demographic model that incorporates two distinct effects of cofactors: that on the transmission of the primary disease from an infected host bearing the cofactor, and that on the acquisition of the primary disease by an individual that is not infected with the primary disease but carries the cofactor.

METHODS

We constructed and analyzed a four-patch compartment model that accommodates a cofactor. We applied the model to HIV spread in the presence of the causal agent of genital schistosomiasis, Schistosoma hematobium, a pathogen commonly co-occurring with HIV in sub-Saharan Africa.

RESULTS

We found that cofactors can have a range of effects on primary disease dynamics, including shifting the primary disease from non-endemic to endemic, increasing the prevalence of the primary disease, and reversing demographic growth when the host population bears only the primary disease to demographic decline. We show that under parameter values based on the biology of the HIV/S. haematobium system, reduction of the schistosome-bearing subpopulations (e.g. through periodic use of antihelminths) can slow and even reverse the spread of HIV through the host population.

CONCLUSIONS

Typical single-disease models provide estimates of future conditions and guidance for direct intervention efforts relating only to the modeled primary disease. Our results suggest that, in circumstances under which a cofactor affects the disease dynamics, the most effective intervention effort might not be one focused on direct treatment of the primary disease alone. The cofactor model presented here can be used to estimate the impact of the cofactor in a particular disease/cofactor system without requiring the development of a more complicated model which incorporates many other specific aspects of the chosen disease/cofactor pair. Simulation results for the HIV/S. haematobium system have profound implications for disease management in developing areas, in that they provide evidence that in some cases treating cofactors may be the most successful and cost-effective way to slow the spread of primary diseases.

Micronutrients and HIV infection

The immune system requires several essential micronutrients to maintain an effective immune response. HIV infection destroys the immune system and promotes nutritional deficiencies, which further impair immunity. This article reviews the role of several micronutrients (vitamins A, C, E and D, the B vitamins, and minerals, selenium, iron and zinc) that are relevant for maintaining immune function. In addition, the deficiencies of these micronutrients have been associated with faster progression of HIV-1 disease. This review examines the evidence from observational studies of an association between micronutrient status and HIV disease, as well as the effectiveness of micronutrient supplementation on HIV-disease progression, pregnancy outcomes and nutritional status, among others, utilizing randomized clinical trials. Each micronutrient is introduced with a summary of its functions in human physiology, followed by the presentation of studies conducted in HIV-infected patients in relation to this specific micronutrient. Overall findings and recommendations are then summarized.

Inhibition of HIV-1 gene expression by Ciclopirox and Deferiprone, drugs that prevent hypusination of eukaryotic initiation factor 5A

BACKGROUND

Eukaryotic translation initiation factor eIF5A has been implicated in HIV-1 replication. This protein contains the apparently unique amino acid hypusine that is formed by the post-translational modification of a lysine residue catalyzed by deoxyhypusine synthase and deoxyhypusine hydroxylase (DOHH). DOHH activity is inhibited by two clinically used drugs, the topical fungicide ciclopirox and the systemic medicinal iron chelator deferiprone. Deferiprone has been reported to inhibit HIV-1 replication in tissue culture.

RESULTS

Ciclopirox and deferiprone blocked HIV-1 replication in PBMCs. To examine the underlying mechanisms, we investigated the action of the drugs on eIF5A modification and HIV-1 gene expression in model systems. At early times after drug exposure, both drugs inhibited substrate binding to DOHH and prevented the formation of mature eIF5A. Viral gene expression from HIV-1 molecular clones was suppressed at the RNA level independently of all viral genes. The inhibition was specific for the viral promoter and occurred at the level of HIV-1 transcription initiation. Partial knockdown of eIF5A-1 by siRNA led to inhibition of HIV-1 gene expression that was non-additive with drug action. These data support the importance of eIF5A and hypusine formation in HIV-1 gene expression.

CONCLUSION

At clinically relevant concentrations, two widely used drugs blocked HIV-1 replication ex vivo. They specifically inhibited expression from the HIV-1 promoter at the level of transcription initiation. Both drugs interfered with the hydroxylation step in the hypusine modification of eIF5A. These results have profound implications for the potential therapeutic use of these drugs as antiretrovirals and for the development of optimized analogs.

Micronutrient status indicators in individuals single- or double-infected with HIV and Wuchereria bancrofti before and after DEC treatment

OBJECTIVE

To identify possible associations between selected micronutrient status indicators (serum ferritin, retinol, beta-carotene, alpha-tocopherol, and the acute phase reactant alpha-1 antichymotrypsin) and infection with human immunodeficiency virus (HIV) or Wuchereria bancrofti, and to assess the effect of the antifilarial drug diethylcarbamazine (DEC) on the micronutrient status indicators in individuals positive for one or both of the two infections.

METHODS

Serum concentrations of ferritin, retinol, beta-carotene, alpha-tocopherol and the acute phase reactant alpha-1 antichymotrypsin were examined in 59 individuals with HIV, W. bancrofti infection, or both, in Tanga Region, Tanzania, before and 12 weeks after treatment with DEC.

RESULTS

HIV infection, but not W. bancrofti infection, was associated with higher serum ferritin concentrations and lower beta-carotene and alpha-tocopherol. Neither HIV infection nor W. bancrofti infection was associated with serum retinol. The four micronutrient status indicators and alpha-1 antichymotrypsin were generally lower at 12 weeks after treatment both in the DEC and the placebo groups.

CONCLUSIONS

The negative association between HIV infection and the antioxidant vitamins beta-carotene and alpha-tocopherol may be due to infection-induced oxidative stress, whereas W. bancrofti infection seemed not to be associated with oxidative stress. The drop in antioxidant vitamin concentrations after treatment may be due to oxidative stress induced by HIV progression (HIV infected) and inflammation around dead adult worms and microfilariae (W. bancrofti infected) rather than to an effect of DEC.

Viral infection and iron metabolism

Fundamental cellular operations, including DNA synthesis and the generation of ATP, require iron. Viruses hijack cells in order to replicate, and efficient replication needs an iron-replete host. Some viruses selectively infect iron-acquiring cells by binding to transferrin receptor 1 during cell entry. Other viruses alter the expression of proteins involved in iron homeostasis, such as HFE and hepcidin. In HIV-1 and hepatitis C virus infections, iron overload is associated with poor prognosis and could be partly caused by the viruses themselves. Understanding how iron metabolism and viral infection interact might suggest new methods to control disease.

The regulation of HIV-1 transcription: molecular targets for chemotherapeutic intervention

The regulation of transcription of the human immunodeficiency virus (HIV) is a complex event that requires the cooperative action of both viral and cellular components. In latently infected resting CD4⁺ T cells HIV‐1 transcription seems to be repressed by deacetylation events mediated by histone deacetylases (HDACs). Upon reactivation of HIV‐1 from latency, HDACs are displaced in response to the recruitment of histone acetyltransferases (HATs) by NF‐κB or the viral transcriptional activator Tat and result in multiple acetylation events. Following chromatin remodeling of the viral promoter region, transcription is initiated and leads to the formation of the TAR element. The complex of Tat with p‐TEFb then binds the loop structures of TAR RNA thereby positioning CDK9 to phosphorylate the cellular RNA polymerase II. The Tat‐TAR‐dependent phosphorylation of RNA polymerase II plays an important role in transcriptional elongation as well as in other post‐transcriptional events. As such, targeting of Tat protein (and/or cellular cofactors) provide an interesting perspective for therapeutic intervention in the HIV replicative cycle and may afford lifetime control of the HIV infection. © 2006 Wiley Periodicals, Inc. Med Res Rev, 26, No. 5, 595–625, 2006

Iron status is an important cause of anemia in HIV-infected Tanzanian women but is not related to accelerated HIV disease progression

In HIV-infected populations from developing countries, it is unclear what proportion of anemia is attributable to iron deficiency (ID) and whether high body iron stores worsen HIV disease progression. We therefore evaluated these research questions in 584 HIV-infected Tanzanian women. Hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (sTfR), and C-reactive protein (CRP) concentrations were evaluated between 13 and 43 wk after women gave birth. ID was defined as SF or sTfR outside normal ranges, and ID anemia (IDA) as ID plus low Hb. In multivariate Cox regression models, the association between SF and HIV disease progression was assessed. Participants received iron + folate supplements during pregnancy. Hb (r = -0.159; P = 0.0001), SF (r = 0.355; P < 0.0001), and sTfR/log SF index (r = -0.119; P = 0.004) were related to CRP, whereas sTfR (r = 0.029; P = 0.48) was not. Prevalence estimates were 39.7% for ID and 23.6% for IDA. ID was associated with 48.9% of anemia cases. Categories of SF were not significantly associated with HIV-related mortality or progression to stage 4. Nevertheless, SF > 150.0 microg/L was related to a nonsignificantly elevated risk of progression to stage 4 (rate ratio = 1.78; 95% CI = 0.68-4.64; P = 0.24) compared with SF < 12.0 microg/L. In HIV-infected, parous women from sub-Saharan Africa, ID is of moderately high prevalence and is an important underlying cause of anemia. High storage iron does not appear to be related to HIV disease progression in this population, but more research on the role of iron during HIV disease is needed.

Micronutrients in HIV-positive persons receiving highly active antiretroviral therapy

In HIV-infected persons, low serum concentrations of vitamins and minerals, termed micronutrients, are associated with an increased risk of HIV disease progression and mortality. Micronutrient supplements can delay HIV disease progression and reduce mortality in HIV-positive persons not receiving highly active antiretroviral therapy (HAART). With the transition to more universal access to HAART, a better understanding of micronutrient deficiencies and the role of micronutrient supplements in HIV-positive persons receiving HAART has become a priority. The provision of simple, inexpensive micronutrient supplements as an adjunct to HAART may have several cellular and clinical benefits, such as a reduction in mitochondrial toxicity and oxidative stress and an improvement in immune reconstitution. We reviewed observational and trial evidence on micronutrients in HIV-positive persons receiving HAART to summarize the current literature and suggest future research priorities. A small number of observational studies have suggested that some, but not all, micronutrients may become replete after HAART initiation, and few intervention studies have found that certain micronutrients may be a beneficial adjunct to HAART. However, most of these studies had some major limitations, including a small sample size, a short duration of follow-up, a lack of adjustment for inflammatory markers, and an inadequate assessment of HIV-related outcomes. Therefore, few data are available to determine whether HAART ameliorates micronutrient deficiencies or to recommend or refute the benefit of providing micronutrient supplements to HIV-positive persons receiving HAART. Because micronutrient supplementation may cause harm, randomized placebo-controlled trials are needed. Future research should determine whether HAART initiation restores micronutrient concentrations, independent of inflammatory markers, and whether micronutrient supplements affect HIV-related outcomes in HIV-positive persons receiving HAART.

Iron chelators may help prevent photoaging

For years, cosmetic ingredients for anti-aging treatments have attracted consumers. Skin aging is accelerated by reactive oxygen species (ROS), generated by exposure to solar ultraviolet radiation (UVR), in a process known as photoaging. Because cutaneous iron catalyses ROS generation, it is thought to play a key role in photoaging. Iron is essential to almost all forms of life. However, excess iron is potentially toxic as its catalytic activity induces the generation of ROS. Iron-catalysed ROS generation is involved in numerous pathological conditions, including cutaneous damage. When skin is directly exposed to UVR, cutaneous intracellular catalytic iron levels increase because of the release of iron from iron-binding proteins such as ferritin. Consequently, the subsequent ROS generation may overwhelm cutaneous defense systems such as the cellular iron sequestration and ROS scavenging capacity. The harmful role of excess cutaneous iron implies that there may be a potential for topical iron chelator treatments. We now consider cutaneous photodamage skin photoaging as the result of iron-catalysed ROS generation and discuss preventative strategies based on iron chelators.

Iron and infection: effects of host iron status and the iron-regulatory genes haptoglobin and NRAMP1 (SLC11A1) on host-pathogen interactions in tuberculosis and HIV

There are many lines of evidence illustrating that iron plays a pivotal role in modulating the battle for survival between mammalian hosts and their pathogens. Each displays considerable genetic investment in a wide range of mechanisms for acquiring and maintaining iron. These competitive mechanisms are highly complex, existing within an interacting matrix of absorption, transport, storage and detoxification systems, each of which are iron-responsive and thus able to adapt to the different phases of infection. Considerable genetic polymorphism in some of these systems, with signals of geographic selection in the hosts, and niche selection in the pathogens, indicates that they are critical for species survival. In this review we briefly summarize the role of iron in host immune function before reviewing the available evidence that iron modulates susceptibility and disease outcomes in HIV and TB (tuberculosis). We then examine the putative role of iron-related host genes by focussing on two candidate genes, haptoglobin and NRAMP1, for which there are common polymorphic variants in humans with strong evidence of functionally distinct biochemical phenotypes that would be predicted to influence the course of HIV and TB infections. Finally, we examine the limited evidence so far available that nutrient-gene interactions are likely to influence the way in which gene variants can protect against infection. We conclude that there is a wealth of evidence associating alterations in iron balance and in iron-regulatory systems with disease progression, but that many issues related to the direction of causality, mechanisms of action and sensitivity to pharmacological intervention remain to be elucidated. Since iron is probably the most widely prescribed compound throughout the world, used in both preventative and treatment regimens, a deeper understanding of the host-pathogen interactions relating to iron constitutes an important area for both basic and clinical research.

Synthesis and Antiviral Evaluation of Cyclic and Acyclic 2-Methyl-3-hydroxy-4-pyridinone Nucleoside Derivatives

A series of cyclic and acyclic nucleoside analogues derived from 3-hydroxy-4-pyridinone were synthesized using the Vorbrüggen reaction. Iron chelation studies, and antiviral evaluation against a broad panel of viruses, were performed. The pK(a) value of ligand 25 and the stability constant of the corresponding iron(III) complex were compared to those of deferiprone. The pFe(3+) values were found to be similar. Some compounds showed moderate activity against both wild-type HSV-1 and HSV-2, as well as against a thymidine kinase deficient strain of HSV-1. These results suggest a novel mode of action for this group of nucleoside analogues.

The effect of iron overload on in vitro HIV-1 infection

BACKGROUND

It has been shown that Fe is required by HIV-infected cells for production of viral particles. Excess iron in the cell is detrimental to the host but beneficial to the pathogen.

OBJECTIVES

Here, we investigated the effect of excess Fe (overload) and chelation of the metal on in vitro HIV infection by assessing host cell responses (viability/death, stress protein expression and cytokine production) as well as virus replication (core protein content and enzyme activity).

RESULTS AND CONCLUSION

Excess iron decreased viability (21%, P<0.01) of HIV-infected cells, increased p24 levels by 8.6% (P=0.32) and elevated reverse transcriptase (RT) activity (81.7%, P<0.01). The stimulation of viral replication was decreased when Fe was first complexed to desferrioxamine (DFO). DFO alone (in the absence of excess Fe), lowered cell viability (35%, P=0.039) and in the presence of virus lowered both p24 levels (66%, P=0.054) and RT activity (43%, P<0.01) and unexpectedly increased cell viability (25%, P=0.01047). Interleukin-2 (IL-2) production of infected cells was completely inhibited by DFO and excess iron while stress protein (Hsp70) levels were lowered in the presence of HIV in combination with excess iron (37%, P<0.01) or DFO (47.2%, P<0.01) when compared to untreated cells. According to flow cytometric data, HIV infection caused a two-fold increase in the numbers of necrotic (P=0.006) and decreased apoptotic cells (28.5%, P=0.15) cells. These findings indicate that Fe overload associated with HIV infection is detrimental to host cell responses against viral infection and that chelation can prevent and/or reverse this effect.

Mechanism of inhibition of the human immunodeficiency virus type 1 by the oxygen radical generating agent bleomycin

Alternative targets of attack of the human immunodeficiency virus (HIV) are necessary in light of infection persistence due to onset of resistance after conventional reverse transcriptase and protease inhibitor therapy. We have recently shown that the cancer chemotherapeutic agent bleomycin (BLM) dose-dependently inhibits HIV-1 replication. The mechanism of this viral inhibition in vitro was investigated. Cell-free wild-type virions were affected directly by BLM in the presence of H2O2, as shown by a 38% decrease of viral infectivity. Viral inhibition by BLM did not proceed via NF-kappaB inhibition. The viral R/U5 DNA product was reduced by 70% without any effect on reverse transcriptase activity. In both a cell-free system as well as two-cell systems the antiviral dependence of BLM on iron and oxidant species was demonstrated. Bleomycin seems to inhibit HIV-1 replication through the same properties that make it a suitable anti-cancer agent. The results presented in this study describe a novel mechanism of HIV-1 inhibition with potential application in viral infections. The anti-HIV effects of BLM in patients receiving this drug in combination with HAART should be carefully monitored in order to evaluate the clinical significance of the findings described in this study.

Synthesis and antiviral evaluation of 3-hydroxy-2-methylpyridin-4-one dideoxynucleoside derivatives

We describe the synthesis and the antiviral evaluation of novel alpha and beta dideoxynucleoside derivatives in which the base has been replaced by a 3-hydroxy-2-methylpyridin-4-one. The syntheses were successfully achieved by the use of the standard Vorbrüggen coupling conditions. Moderate activity of these compounds were found on herpes simplex virus (HSV) type 1 and type 2.

Changes in function of iron-loaded alveolar macrophages after in vivo administration of desferrioxamine and/or chloroquine

Both desferrioxamine (DFO) and chloroquine can significantly reduce hepatic iron in experimental animals with iron overload by chelating iron from the low-molecular-weight pool or decreasing iron uptake by the transferrin-transferrin receptor cycle, respectively. However, no previous studies have investigated whether combination therapy of these two drugs would further decrease the tissue iron overload as well as iron-induced toxicity. Chloroquine administration, 15 mg/kg, 5x/week, to rats during the iron loading regime, 10 mg/kg, 3x/week for 4 weeks, significantly decreased both hepatic (54%) and macrophage iron content (24%). However when administered in combination with desferrioxamine, 10 mg/kg, 3x/week for 2 weeks at the cessation of iron loading, no further reduction of hepatic iron content was noted while the iron content of the macrophages significantly increased, possibly indicating the flux of ferrioxamine through these cells. Further studies are warranted to investigate the speciation of iron within these macrophages. Macrophages isolated from chloroquine-treated iron loaded rats showed a reduction in latent NFkappaB activation and a significant increase in lipopolysaccharide-stimulated nitrite release by comparison to these parameters in iron loaded macrophages. Co-administration of chloroquine and desferrioxamine normalised the latent activity of NFkappaB to that of control macrophages as well as increasing LPS-stimulated NO release towards control values. However, DFO alone did not have any significant effect upon either of these parameters. Such results may have important relevance for the reduced immune function of iron loaded macrophages isolated from thalassaemia patients receiving chelation therapy and their propensity to increased infection.

In vitro effects of ascorbate and Trolox on the biocompatibility of dental restorative materials

Previous in vitro studies on the cytotoxicity of eight dental restorative materials including composites, compomers, resin-modified glass ionomer cements and glass ionomer cements have demonstrated a depletion of intracellular glutathione in gingival fibroblasts incubated with eluates of these materials and a protective effect of N-acetylcysteine. In the present study, we investigate the effects of two other antioxidants: ascorbate and Trolox. It was found that Trolox reduced the cytotoxicity induced by resin-based biomaterial eluates. In contrast, ascorbate increased in a dose-dependent manner the toxic effect of all eluates except for Z100 MP and Tetric flow (composites). The effect of D-mannitol was studied for GC FUJI II and was found to neutralize the additional toxic effect of ascorbate. Ascorbate increased the depletion of intracellular glutathione of these dental material eluates (between 17% and 24%, depending on the material). Quantification of metal ions in the dental material eluates showed the presence of significant amounts of aluminum and iron in GC FUJI II > photac fil > GC FUJI II LC > F2000. The mechanism of this increased cytotoxicity could be explained by the Fenton reaction resulting from the pro-oxidant effect of ascorbate in the presence of iron (transition metal ions) and/or aluminum.

Ferritin and desferrioxamine attenuate xanthine oxidase-dependent leak in isolated perfused rat lungs

Iron, through its participation in reactions that generate reactive oxygen species, may contribute to the oxidative lung injury observed in patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). A number of investigators have shown that the endogenous iron storage protein ferritin increases in the blood of patients with and at-risk for ALI and ARDS, but the significance of these increases are not known. In the present investigation, we measured lung tissue levels of thiobarbituric acid reactive substances (TBARS) and lung leak in isolated rat lungs perfused with xanthine oxidase (XO) and purine, an enzymatic system which generates reactive oxygen species. We found that adding ferritin (100 ng/mL) or desferrioxamine (DFO, 10 mM), an iron chelator, to the vascular perfusate solution decreased oxidant-induced leak in isolated rat lungs perfused with XO and purine. Addition of ferritin or DFO also decreased TBARS in isolated rat lungs perfused with XO and purine; neither ferritin nor DFO, however, decreased XO activity in vitro. Our results suggest that oxidative lung leak may be altered by the availability of reactive iron and that ferritin may contribute to protection against oxidative lung injury.

Human immunodeficiency virus type 1 replication inhibition by the bidentate iron chelators CP502 and CP511 is caused by proliferation inhibition and the onset of apoptosis

BACKGROUND

The iron chelators deferoxamine (DF) and deferiprone (CP20) have been shown to inhibit human immunodeficiency virus type 1 (HIV-1) replication in human peripheral blood lymphocytes (PBL). The orally active bidentate chelators CP502 and CP511, which also belong to the 3-hydroxypyridin-4-one family, but with higher affinities for iron than CP20, were monitored for their antiviral properties by checking for p24 antigen production and nuclear factor (NF)-kappaB activation, and their ability to induce apoptosis.

MATERIALS AND METHODS

Human PBLs were isolated from HIV-1 seronegative donors and subsequently infected with HIV-1(Ba-L) for 2 h. After 5 days' incubation, HIV-1 replication was monitored by p24 antigen production. Cellular proliferation as well as caspase-3 activity were monitored in uninfected cells after a period of 5 days and after 1 day infection, respectively. NF-kappaB activity was also monitored by electromobility shift assays (EMSA) performed on nuclear extracts of Jurkat cells treated with the different chelators for 4 h.

RESULTS

CP502 and CP511 decrease HIV-1 replication by decreasing cellular proliferation in a similar manner to DF and CP20. CP511 seemed to be more potent than either CP502 or CP20. Due to the reduction in cellular proliferation, there was an increase in caspase-3 activity after 24 h incubation. NF-kappaB activity was not affected by any of the chelators.

CONCLUSIONS

Iron chelators with high affinities for iron, which are under development for the treatment of iron overload, could contribute to the reduction of HIV-1 replication in infected patients by cellular proliferation inhibition rather than by a direct antiviral action.

The potential place of chloroquine in the treatment of HIV-1-infected patients

BACKGROUND

Chloroquine has been reported to be endowed with anti-HIV-1 activity. We previously found its anti-HIV-1 activity to be additive to that of of the hydroxyurea plus didanosine combination.

OBJECTIVES

Here we wish to present reported data on chloroquine's effects other than its antiretroviral activity, that may be of benefit in the therapy of HIV-1-infected individuals.

RESULTS

(1) Chloroquine exerts an inhibitory effect on several AIDS-opportunistic pathogens, at least in vitro and, in some cases, in murine infections. (2) The drug exerts an inhibitory effect on the synthesis of several pro-inflammatory cytokines that may play a pathogenic role in the progression of HIV infection. (3) The drug has the potential to restrict tissular iron accumulation that may play a negative role in HIV infection. (4) The drug has practical advantages, as it is widely distributed, inexpensive and not stigmatizing. (5) We hypothesized that the drug, if given to HIV-positive breast-feeding mothers, may be of potential benefit in decreasing the rate of mother-to-child transmission of HIV-1.

CONCLUSION

in view of the above-given data, combination therapy with chloroquine warrants clinical studies in HIV-1-infected patients, mainly in the setting of resource-poor countries.

Anti-HIV effect of iron chelators: different mechanisms involved

BACKGROUND

Drugs for the treatment of AIDS have been directed to specific events in the human immunodeficiency virus (HIV-1) life cycle, aimed to stop viral replication by inhibition of reverse transcriptase or protease activity. Studies showing that oxidative stress and iron may be important in the activation of HIV-1 have focused attention on the potential therapeutic use of iron chelators.

OBJECTIVES

The goal of this review is to describe several possibilities as to how iron is involved in the replication of HIV and how iron chelation may interfere in this process.

STUDY DESIGN

First some physico-chemical properties of iron concerning solubility, oxidation-reduction potential, catalysis, and chelation will be discussed. In the second part, the role of iron in various biochemical systems is explained.

RESULTS

Nuclear factor kappa B (NF-kappaB) activation, regulating proviral transcription, can be influenced by iron through the production of reactive oxygen species. A second route by which iron chelation could influence HIV replication, is by inhibition of DNA synthesis through inactivation of iron-dependent ribonucleotide reductase. Another strategy which can be employed in targeting iron chelators against HIV-1, is direct oxidative viral RNA/DNA attack. This could be achieved by bleomycin, a cytostatic agent with the ability to form a complex with DNA and RNA.

CONCLUSION

Chelation may withhold iron from viral metabolism but on the other hand may also favor catalysis of reactive oxygen species directed to viral constituents. In combination with existing antivirals, iron chelation could add to improve the treatment of HIV-disease.

Human Immunodeficiency Virus Type 1 Tat Protein Impairs Selenoglutathione Peroxidase Expression and Activity by a Mechanism Independent of Cellular Selenium Uptake: Consequences on Cellular Resistance to UV-A Radiation

The expression of the HIV-1 Tat protein in HeLa cells resulted in a 2.5-fold decrease in the activity of the antioxidant enzyme glutathione peroxidase (GPX). This decrease seemed not to be due to a disturbance in selenium (Se) uptake. Indeed, the intracellular level of Se was similar in parental and tat-transfected cells. A Se enrichment of the medium did not lead to an identical GPX activity in both cell lines, suggesting a disturbance in Se utilization. Total intracellular 75Se selenoproteins were analyzed. Several quantitative differences were observed between parental and tat-transfected cells. Mainly, cytoplasmic glutathione peroxidase and a 15-kDa selenoprotein were decreased in HeLa-tat cells, while phospholipid hydroperoxide glutathione peroxidase and low-molecular-mass selenocompounds were increased. Thioredoxin reductase activity and total levels of 75Se-labeled proteins were not different between the two cell types. The effect of Tat on GPX mRNA levels was also analyzed. Northern blots revealed a threefold decrease in the GPX/glyceraldehyde phosphate dehydrogenase mRNA ratio in HeLa-tat versus wild type cells. By deregulating the intracellular oxidant/antioxidant balance, the Tat protein amplified UV sensitivity. The LD50 for ultraviolet radiation A was 90 J/cm2 for HeLa cells and only 65 J/cm2 for HeLa-tat cells. The oxidative stress occurring in the Tat-expressing cells and demonstrated by the diminished ratio of reduced glutathione/oxidized glutathione was not correlated with the intracellular metal content. Cellular iron and copper levels were significantly decreased in HeLa-tat cells. All these disturbances, as well as the previously described decrease in Mn superoxide dismutase activity, are part of the viral strategy to modify the redox potential of cells and may have important consequences for patients.

Trace elements in regulation of NF-kappaB activity

In recent years several studies have shown that NF-kappaB might be a very important therapeutic target in the treatment ot various chronic inflammatory, degenerative and tumour diseases. Trace elements play essential roles in the regulation ot cell signaling mechanisms via transcription tactors and a large number of genes. An important aspect of the present review is the description ot the mechanisms by which trace elements might influence transcription factor NF-kappaB. DNA-binding activity of NF-kappaB is regulated by the redox state of the cysteine residue (Gys-62) in the DNA binding domain of the p50 subunit and impaired by different metals (Go, Cr, Ni, Cd, Pb). It has been hypothesised that the broad speciticity of interrelationships between NF-kappaB. AP-1 and various metals results from interactions of metals with specific moieties of transcription factors and IkappaB-kinases, as well as trom the existence of a metal-governed redox system. The hypothetical targets in the NF-kappaB signaling pathway affected by metals are: IkappaB-kinases, IkappaBs, NF-kappaB, proteasome degradation of NF-kappaB, kappaB-sites in DNA. Possibly, this system is required by the cell for adequate regulation ot the transcription machinery in response to changes in intracellular and intranuclear fluxes of metals and radicals and is very ancient evolutionary mechanism of stress adaptation. The role of the NF-kappaB-mediated mechanism in induction or prevention of chronic intlammatory, allergic, degenerative and tumor diseases by zinc, vanadium, manganese, copper, silica, iodine and other trace elements is discussed.

Development of brain injury in mice by Angiostrongylus cantonensis infection is associated with the induction of transcription factor NF-kappaB, nuclear protooncogenes, and protein tyrosine phosphorylation

Eosinophilic meningitis or meningoencephalitis caused by Angiostrongylus cantonensis is endemic to the Pacific area of Asia, especially Taiwan, Thailand, and Japan. Although eosinophilia is an important clinical manifestation of A. cantonensis infection, the role of eosinophils in the progress of the infection remains to be elucidated. In this experiment, we showed that A. cantonensis-caused eosinoplia and inflammation might lead to the induction of NF-kappaB and protooncogene expression via activation of the tyrosine phosphorylation signal pathway. After mice were infected daily with 30 third-stage larvae of A. cantonensis by oral adminstration for 6 weeks, no significant differences PKC-alpha, MEK-1, ERK-2, JNK, and p38 protein expression were found between the control and infected mice. However, the protein tyrosine phosphorylation levels, NF-kappaB, and iNOS protein products were significantly increased by 3.5-, 3.3-, and 6.3-fold, respectively, after 3 weeks of A. cantonensis infection. The same pattern was found for c-Myc, c-Jun, and c-Fos proteins, which were elevated by 3.2-, 2.3-, and 3.4-fold, respectively, compared to control animals after 3 weeks. The expression potency of these proteins started increasing in week 1, reaching maximal induction in week 3, and then declining in week 5 after A. cantonensis infection. Another consistent result was noted in the pathological observations, including eosinophilia, leukocyte infiltration, granulomatous reactions, and time responses in brain tissues of infected mice. These data suggest that the development of brain injury by eosinophlia of A. cantonensis infection is associated with NF-kappaB and/or nuclear protooncogenes expression, which is activated by the tyrosine phosphorylation pathway.

The pivotal role of iron in NF-kappa B activation and nigrostriatal dopaminergic neurodegeneration. Prospects for neuroprotection in Parkinson's disease with iron chelators

R-Apomorphine (APO) the catechol-derived dopamine D1-D2 receptor agonist has been shown to be highly potent iron chelator and radical scavenger and inhibitor of membrane lipid peroxidation in vitro, in vivo and in cell culture employing PC12 cells. Its potency has been compared to the prototype iron chelator desferrioxamine (desferal), dopamine, nifedipine and dopamine D2 receptor agonists, bromocriptine, lisuride, pergolide and pramipexole. APO also inhibits brain and mitochondrial protein oxidation. In vivo APO protects against MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)- induced striatal dopaminergic neurodegeneration in C57 black mice with as low as 5 mg/kg. APO is a reversible competitive inhibitor of monoamine oxidase (MAO) A and B with IC50 values of 93 and 214 uM, respectively. The iron chelating and radical scavenging actions of desferal and APO explains their ability to inhibit iron and 6-hydroxydopamine (6-OHDA)-induced neurodegeneration and activation of redox-sensitive transcription factor NF-kappa B and the subsequent transactivation of promoters of genes involved in inflammatory cytokines. Iron is thought to play a pivotal role in neurodegeneration, and APO may be an ideal drug to investigate neuroprotection in Parkinson's disease where iron and oxidative stress have been implicated in the pathogenesis of nigrostriatal dopamine neuron degeneration.

Antiviral and immunomodulatory effects of desferrioxamine in cytomegalovirus-infected rat liver allografts with rejection

BACKGROUND

Cytomegalovirus (CMV) infection is associated with acute and chronic allograft rejection. We have recently shown that rat CMV increases portal inflammation and bile duct destruction in a model of rat liver allograft rejection. Desferrioxamine (DFO), an iron chelator and antioxidant, has recently been demonstrated to have antiviral as well as immunomodulatory effects in vitro. We therefore investigated whether DFO inhibits (a) CMV infection and (b) graft destruction in our rat model.

METHOD

One day after liver transplantation, PVG (RT1c) into BN(RT1n), the rats were infected with rat CMV (RCMV, Maastricht strain; 10(5) plaque-forming units i.p.). The effects of 100 mg/kg body weight and 200 mg/kg body weight DFO were examined.

RESULTS

In the untreated group, the grafts were uniformly RCMV culture-positive. In the group receiving 200 mg/kg DFO, RCMV replication was effectively inhibited. Inflammatory response in the graft, and especially the number of macrophages, was significantly reduced by DFO. Portal inflammation and bile duct destruction were also significantly reduced. In the untreated group, the bile duct epithelial cells were found to be strongly positive for tumor necrosis factor-alpha and this expression was clearly decreased by DFO. In addition, DFO significantly inhibited vascular cell adhesion molecule-1 expression on sinusoidal endothelial cells.

CONCLUSIONS

Our in vivo transplant study strongly supports the inhibitory effects of metal chelators on CMV infection and their possible usefulness in the treatment of CMV-induced pathogenic changes.