Silica nanoparticles induce oxidative stress and inflammation of human peripheral blood mononuclear cells

In the present study, the effects of 10- or 100-nm silica oxide (SiO₂) NPs on human peripheral blood mononuclear cells (PBMC) were examined. Cytotoxic effects and oxidative stress effects, including glutathione (GSH) depletion, the formation of protein radical species, and pro-inflammatory cytokine responses, were measured. PBMC exposed to 10-nm NP concentrations from 50 to 4,000 ppm showed concentration-response increases in cell death; whereas, for 100-nm NPs, PBMC viability was not lost at <500 ppm. Interestingly, 10-nm NPs were more cytotoxic and induced more oxidative stress than 100-nm NPs. Immunoelectron micrographs show the cellular distribution of GSH and NPs. As expected based on the viability data, the 10-nm NPs disturbed cell morphology to a greater extent than did the 100-nm NPs. Antibody to the radical scavenger, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), was used for Western blot analysis of proteins with radicals; more DMPO proteins were found after exposure to 10-nm NPs than 100-nm NPs. Examination of cytokines (TNF-α, IL-1ra, IL-6, IL-8, IL-1β, and IFN-γ) indicated that different ratios of cytokines were expressed and released after exposure to 10- and 100-nm NPs. IL-1β production was enhanced by 10- and 100-nm NPs;, the cytotoxicity of the NPs was associated with an increase in the IL-1β/IL-6 ratio and 100-nm NPs at concentrations that did not induce loss of cell viability enhanced IL-1β and IL-6 to an extent similar to phytohemagglutinin (PHA), a T cell mitogen. In conclusion, our results indicate that SiO₂ NPs trigger a cytokine inflammatory response and induce oxidative stress in vitro, and NPs of the same chemistry, but of different sizes, demonstrate differences in their intracellular distribution and immunomodulatory properties, especially with regard to IL-1β and IL-6 expression.     

Differential gene expression in normal and transformed human mammary epithelial cells in response to oxidative stress

Oxidative stress plays a key role in breast carcinogenesis. To investigate whether normal and malignant breast epithelial cells differ in their responses to oxidative stress, we examined the global gene expression profiles of three cell types, representing cancer progression from a normal to a malignant stage, under oxidative stress. Normal human mammary epithelial cells (HMECs), an immortalized cell line (HMLER-1), and a tumorigenic cell line (HMLER-5) were exposed to increased levels of reactive oxygen species (ROS) by treatment with glucose oxidase. Functional analysis of the metabolic pathways enriched with differentially expressed genes demonstrated that normal and malignant breast epithelial cells diverge substantially in their response to oxidative stress. Whereas normal cells exhibit the up-regulation of antioxidant mechanisms, cancer cells are unresponsive to the ROS insult. However, the gene expression response of normal HMECs under oxidative stress is comparable to that of the malignant cells under normal conditions, indicating that altered redox status is persistent in breast cancer cells, which makes them resistant to increased generation of ROS. We discuss some of the possible adaptation mechanisms of breast cancer cells under persistent oxidative stress that differentiate them from normal mammary epithelial cells as regards the response to acute oxidative stress.     

Hypoxic preconditioning increases survival and angiogenic potency of peripheral blood mononuclear cells via oxidative stress resistance

Cell-based angiogenesis is a promising treatment for ischemic diseases; however, the survival of implanted cells is impaired by oxidative stress in the ischemic microenvironment. We tested the hypothesis that hypoxic preconditioning of implanted cells enhances their resistance against oxidative stress, increasing cell survival and angiogenic potency after implantation into ischemic tissue. Mouse peripheral blood mononuclear cells (PBMNCs) were collected and subjected to hypoxic preconditioning by culture for 24 h in 2% O(2) at 33 degrees C. Hypoxic preconditioning of PBMNCs increased the expression of various genes related to antioxidant and survival signals remarkably. Compared with cells cultured under normoxia, the hypoxia-preconditioned PBMNCs showed significantly lower reactive oxygen species (ROS) accumulation and higher cell survival under oxidative stress induced by LY-83583 (a superoxide generator). Three days after intramuscular implantation into the ischemic hindlimbs of mice, survival of the hypoxia-preconditioned PBMNCs was high, whereas that of the normoxia-cultured PBMNCs was relatively low. Furthermore, 28 days after treatment microvessel density and blood flow in the ischemic hindlimbs were significantly better in the mice implanted with hypoxia-preconditioned PBMNCs than in those implanted with normoxia-cultured PBMNCs. Hypoxic preconditioning increased the survival and angiogenic potency of PBMNCs, through oxidative stress resistance mechanisms.     

Apoptosis and oxidative status in peripheral blood mononuclear cells of diabetic patients

We have compared the concentrations of intracellular glutathione (GSH), glutathione-dependent antioxidative enzymes, the cell death rate and immunophenotype profile of peripheral blood mononuclear cells (PBMC) from healthy donors and from patients with insulin-dependent type I (IDDM) or non insulin-dependent type II (NIDDM) diabetes mellitus. The IDDM and NIDDM patients had above-normal absolute lymphocyte counts, whereas the percentages of CD3, CD4 and CD8 T lymphocytes were significantly reduced. In contrast, the absolute number and percentage of B lymphocytes was higher in diabetic patients than in healthy donors. The low intracellular reduced glutathione (GSH) and the unbalanced profile of key enzymes involved in GSH metabolism, gamma glutamyltransferase (-GT) and glutathione-S-transferase (GST), account for the increased oxidative status of PBMC from diabetic patients. The plasma membranes of PBMC from diabetic patients were less permeable to propidium iodide than those of PBMC from healthy donors, indicating that the apoptotic cell death rate was lower in the cells from diabetic patients. These differences are potentially useful markers of pathogenic metabolic changes which occur during clinical diabetes and if they are confirmed could be used to identify the onset of diabetes.     

Association between T lymphocyte sub-sets apoptosis and peripheral blood mononuclear cells oxidative stress in systemic lupus erythematosus

Abstract

Increased oxidative stress and lymphocyte apoptosis are a hallmark of the autoimmune disease systemic lupus erythematosus (SLE). However, the association between oxidative stress and T lymphocytes apoptosis has still to be elucidated in SLE. In order to appraise the interaction between oxidative stress and T lymphocyte apoptosis with the severity of disease, oxidative stress profile and T lymphocytes apoptosis were studied. Increased levels of ROS, MDA and CD4⁺ lymphocyte apoptosis were positively associated with disease activity while decreased levels of GSH and percentage expression of CD4⁺ lymphocyte were negatively associated with disease activity. The decrease in intracellular levels of GSH was negatively associated with T lymphocyte, CD4⁺ lymphocyte, CD8⁺ lymphocyte apoptosis and intracellular caspase-3 expression. The present study suggests that increased T lymphocyte sub-sets apoptosis may be mediated by decreased intracellular glutathione concentration and severity of disease might be enhanced together by over-production of ROS in SLE.     

Association between T lymphocyte sub-sets apoptosis and peripheral blood mononuclear cells oxidative stress in systemic lupus erythematosus

Increased oxidative stress and lymphocyte apoptosis are a hallmark of the autoimmune disease systemic lupus erythematosus (SLE). However, the association between oxidative stress and T lymphocytes apoptosis has still to be elucidated in SLE. In order to appraise the interaction between oxidative stress and T lymphocyte apoptosis with the severity of disease, oxidative stress profile and T lymphocytes apoptosis were studied. Increased levels of ROS, MDA and CD4(+) lymphocyte apoptosis were positively associated with disease activity while decreased levels of GSH and percentage expression of CD4(+) lymphocyte were negatively associated with disease activity. The decrease in intracellular levels of GSH was negatively associated with T lymphocyte, CD4(+) lymphocyte, CD8(+) lymphocyte apoptosis and intracellular caspase-3 expression. The present study suggests that increased T lymphocyte sub-sets apoptosis may be mediated by decreased intracellular glutathione concentration and severity of disease might be enhanced together by over-production of ROS in SLE.     

Kinetic study of cytokines production by human peripheral blood mononuclear cells in response to Brucella DNA

In spite of reports on cytokines induction by the Brucella DNA in murine model, there is no comparison between pathogenic and appropriate vaccine strains in human. We investigated the cytokines profile of human peripheral blood mononuclear cells (PBMCs) induced by DNA extracted from pathogenic isolates of Brucella melitensis and B. abortus as well as Rev1 and S19; the appropriate vaccine strains. It was observed that despite differential induction of Interleukin(IL)-12 and IL-10 production, identical IL-12/IL-10 concentration ratio was obtained by all Brucella strains DNAs that was 2 after 24h and 4 after 5 days of incubation. In addition, IL-2 and Interferon(IFN)-gamma production were profoundly increased compared to the medium at day 3 and 5 respectively but IFN-alpha was not induced. Therefore, Brucella strains DNAs are Th1 inducing component with similar pattern in human PBMCs.     

The effects of rosmarinic acid on oxidative stress parameters and inflammatory cytokines in lipopolysaccharide-induced peripheral blood mononuclear cells

Molecular Biology Reports - Rosmarinic acid (RA) is a potential herbal medicine and has received considerable attention due to its strong antioxidant properties. The aim of this study is to...     

Sex as a response to oxidative stress: stress genes co-opted for sex

Despite a great deal of interest, the evolutionary origins and roles of sex remain unclear. Recently, we showed that in the multicellular green alga, Volvox carteri, sex is a response to increased levels of reactive oxygen species (ROS), which could be indicative of the ancestral role of sex as an adaptive response to stress-induced ROS. To provide additional support for the suggestion that sex evolved as a response to oxidative stress, this study addresses the hypothesis that genes involved in sexual induction are evolutionarily related to genes associated with various stress responses. In particular, this study investigates the evolutionary history of genes specific to the sexual induction process in V. carteri--including those encoding the sexual inducer (SI) and several SI-induced extracellular matrix (ECM) proteins. Surprisingly, (i) a highly diversified multigene family with similarity to the V. carteri SI and SI-induced pherophorin family is present in its unicellular relative, Chlamydomonas reinhardtii (which lacks both a SI and an ECM) and (ii) at least half of the 12 identified gene members are induced (as inferred from reported expressed sequence tags) under various stress conditions. These findings suggest an evolutionary connection between sex and stress at the gene level, via duplication and/or co-option.     

Identification of interleukin-13 related biomarkers using peripheral blood mononuclear cells

Asthma is a chronic disorder characterized by airway inflammation, reversible bronchial obstruction, hyper-responsiveness and remodelling. Data from human in vitro studies and experimental in vivo models of asthma has implicated interleukin (IL)-13 in the asthma phenotype suggesting that a therapeutic agent against it could be effective in treating asthma. The role of biomarkers is becoming increasingly important in the clinical development of therapeutics. Here we describe the use of the GeneChip^® DNA microarray technology platform to explore and identify potential response to therapy biomarkers that are associated with the biology of IL-13. Peripheral blood mononuclear cells (PBMCs) from eight healthy donors were cultured in the presence of IL-13, IL-4, an anti-IL-13 monoclonal antibody (mAb) or an isotype control mAb, and RNA from the treated cells was subjected to microarray analysis. The results revealed a number of genes, such as CCL17 (TARC), CCL22 (MDC), CCL23 (MPIF-1), CCL26 (eotaxin 3) and WNT5A (human wingless-type MMTV integration site family member 5A), that showed increased expression in the IL-13 and IL-4 treatment groups. Real-time polymerase chain reaction (PCR) subsequently confirmed these results. A follow-up study in PBMCs from five additional healthy donors showed that the neutralization of IL-13 completely blocked IL-13-induced TARC, MDC and eotaxin 3 production at the protein level. These data suggest that TARC, MDC, eotaxin 3, CCL23 and WNT5A if validated could serve as potential biomarkers for anti-IL-13 therapeutics.     

Identification of interleukin-13 related biomarkers using peripheral blood mononuclear cells

Asthma is a chronic disorder characterized by airway inflammation, reversible bronchial obstruction, hyper-responsiveness and remodelling. Data from human in vitro studies and experimental in vivo models of asthma has implicated interleukin (IL)-13 in the asthma phenotype suggesting that a therapeutic agent against it could be effective in treating asthma. The role of biomarkers is becoming increasingly important in the clinical development of therapeutics. Here we describe the use of the GeneChip^® DNA microarray technology platform to explore and identify potential response to therapy biomarkers that are associated with the biology of IL-13. Peripheral blood mononuclear cells (PBMCs) from eight healthy donors were cultured in the presence of IL-13, IL-4, an anti-IL-13 monoclonal antibody (mAb) or an isotype control mAb, and RNA from the treated cells was subjected to microarray analysis. The results revealed a number of genes, such as CCL17 (TARC), CCL22 (MDC), CCL23 (MPIF-1), CCL26 (eotaxin 3) and WNT5A (human wingless-type MMTV integration site family member 5A), that showed increased expression in the IL-13 and IL-4 treatment groups. Real-time polymerase chain reaction (PCR) subsequently confirmed these results. A follow-up study in PBMCs from five additional healthy donors showed that the neutralization of IL-13 completely blocked IL-13-induced TARC, MDC and eotaxin 3 production at the protein level. These data suggest that TARC, MDC, eotaxin 3, CCL23 and WNT5A if validated could serve as potential biomarkers for anti-IL-13 therapeutics.     

Pleiotrophin induces expression of inflammatory cytokines in peripheral blood mononuclear cells

Pleiotrophin (PTN) is a polypeptide that belongs to a family of heparin-binding growth factor, which displays mitogenic activity for a wide variety of cells. Since PTN induces the proliferation of immune cells the mechanism of action was investigated. In the present study, we show for the first time that PTN induces the expression of inflammatory cytokines including TNF-alpha, IL-1beta and IL-6 in quiescent human peripheral blood mononuclear cells (PBMC). These results emphasize the importance of PTN in the regulation of inflammatory processes. Elucidation of the mechanisms by which a host factor such PTN regulates cytokines production will significantly advance our understanding of endothelium-immunity interactions.     

Pravastatin sodium attenuated TREM-1-mediated inflammation in human peripheral blood mononuclear cells

Pravastatin sodium on triggering receptor expressed on myeloid cell-1 (TREM-1)-mediated inflammation in human peripheral blood mononuclear cells (PBMCs) has been poorly investigated. In this study, we isolated PBMCs from the peripheral blood samples of patients with chronic obstructive pulmonary disease, treated the cells with pravastatin sodium, and determined a concentration at which more than 90% cells could survive. Then we treated cells with 10?ng/ml of lipopolysaccharide, added with 10, 50, 100?μM of pravastatin sodium combined with or without LR-12, a known TREM-1 inhibitor. The expression of TREM-1 was determined by quantitative RT-PCR. The levels of TREM-1, IL-6, and TNF-α in cell culture supernatant were measured with ELISA. Simultaneously, NF-κB signaling pathway-related protein p-p65 and p-IκBα were detected by Western blot assay. Results demonstrated that pravastatin sodium significantly mitigated lipopolysaccharide-stimulated TREM-1 over-expression at mRNA and protein levels dose-dependently. Elevated IL-6 and TNF-α levels changed synchronously. LR-12 inhibited the TREM-1 over-expression and inflammatory factor production but did not show extra synergistic effect to pravastatin. Lipopolysaccharide induced phospho-p65 and -IκBα over-expression was weakened significantly when cells were treated with pravastatin sodium. In conclusion, pravastatin could inhibit TREM-1-medieted inflammation and NF-κB signaling pathway was involved.