The effect of strong static magnetic field on lymphocytes

We investigated whether static electromagnetic fields (EMFs) at a flux density of 4.75 T, generated by an NMR apparatus (NMRF), could promote movements of Ca2+, cell proliferation, and the eventual production of proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC) as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 mg/ml phytohaemagglutinin (PHA). Our results clearly demonstrate that static NMRF exposure has neither proliferative, nor activating, nor proinflammatory effects on both normal and PHA activated PBMC. Moreover, the concentration of interleukin-1beta, interleukin-2, interleukin-6, interferon, and tumour necrosis factor alpha (TNFalpha) remained unvaried in exposed cells. Exposure of Jurkat cells statistically decreased the proliferation and the proliferation indexes, which 24 and 48 h after exposure were 0.7 +/- 0.29 and 0.87 +/- 0.12, respectively. Moreover, in Jurkat cells the [Ca2+]i was higher than in PBMC and was reduced significantly to about one half after exposure. This is consistent with the decrease of proliferation and with the low levels of IL-2 measured. On the whole, our data suggest that NMRF exposure failed to affect the physiologic behaviour of normal lymphomonocytes. Instead in Jurkat cells, by changing the properties of cell membranes, NMRF can influence Ca2+ transport processes, and hence Ca2+ homeostasis with improvement of proliferation.     

Cortisol-induced CXCR4 augmentation mobilizes T lymphocytes after acute physical stress

The aim of this study was to elucidate the mechanism responsible for lymphopenia after exercise. Seven young healthy men volunteered for this study. Peripheral blood mononuclear cells (PBMC) were cultured with cortisol and analyzed for C-X-C motif chemokine receptor 4 (CXCR4) expression by flow cytometry. To determine the effects of exercise, subjects performed exhaustive cycling exercise. PBMC were cultured with plasma obtained before and after the cycling exercise. Alternatively, PBMC obtained before and after exercise were cultured without plasma or glucocorticoid to examine whether PBMC were primed in vivo for CXCR4 expression. We analyzed cortisol- or plasma-treated PBMC to determine their ability to migrate through membrane filters in response to stromal cell-derived factor 1alpha/CXCL12. Cortisol dose- and time-dependently augmented CXCR4 expression on T lymphocytes, with <6 h of treatment sufficient to augment CXCR4 on T lymphocytes. Postexercise plasma also augmented CXCR4 expression. Cortisol or postexercise plasma treatment markedly enhanced migration of T lymphocytes toward CXCL12. Augmentation of CXCR4 on T lymphocytes by cortisol or plasma was effectively blocked by the glucocorticoid receptor antagonist RU-486. Thus exercise-elicited endogenous cortisol effectively augments CXCR4 expression on T lymphocytes, which may account for lymphopenia after exercise.     

Evaluation of functional erythropoietin receptor status in skeletal muscle in vivo: acute and prolonged studies in healthy human subjects

Background

Erythropoietin receptors have been identified in human skeletal muscle tissue, but downstream signal transduction has not been investigated. We therefore studied in vivo effects of systemic erythropoietin exposure in human skeletal muscle.

Methodology/Principal Findings

The protocols involved 1) acute effects of a single bolus injection of erythropoietin followed by consecutive muscle biopsies for 1–10 hours, and 2) a separate study with prolonged administration for 16 days with biopsies obtained before and after. The presence of erythropoietin receptors in muscle tissue as well as activation of Epo signalling pathways (STAT5, MAPK, Akt, IKK) were analysed by western blotting. Changes in muscle protein profiles after prolonged erythropoietin treatment were evaluated by 2D gel-electrophoresis and mass spectrometry. The presence of the erythropoietin receptor in skeletal muscle was confirmed, by the M20 but not the C20 antibody. However, no significant changes in phosphorylation of the Epo-R, STAT5, MAPK, Akt, Lyn, IKK, and p70S6K after erythropoietin administration were detected. The level of 8 protein spots were significantly altered after 16 days of rHuEpo treatment; one isoform of myosin light chain 3 and one of desmin/actin were decreased, while three isoforms of creatine kinase and two of glyceraldehyd-3-phosphate dehydrogenase were increased.

Conclusions/Significance

Acute exposure to recombinant human erythropoietin is not associated by detectable activation of the Epo-R or downstream signalling targets in human skeletal muscle in the resting situation, whereas more prolonged exposure induces significant changes in the skeletal muscle proteome. The absence of functional Epo receptor activity in human skeletal muscle indicates that the long-term effects are indirect and probably related to an increased oxidative capacity in this tissue.     

Oxidatively damaged DNA and its repair after experimental exposure to wood smoke in healthy humans

Particulate matter from wood smoke may cause health effects through generation of oxidative stress with resulting damage to DNA. We investigated oxidatively damaged DNA and related repair capacity in peripheral blood mononuclear cells (PBMC) and measured the urinary excretion of repair products after controlled short-term exposure of human volunteers to wood smoke. Thirteen healthy adults were exposed first to clean air and then to wood smoke in a chamber during 4h sessions, 1 week apart. Blood samples were taken 3h after exposure and on the following morning, and urine was collected after exposure, from bedtime until the next morning. We measured the levels of DNA strand breaks (SB), oxidized purines as formamidopyrimidine-DNA-glycosylase (FPG) sites and activity of oxoguanine glycosylase 1 (hOGG1) in PBMC by the comet assay, whereas mRNA levels of hOGG1, nucleoside diphosphate linked moiety X-type motif 1 (hNUDT1) and heme oxygenase 1 (hHO1) were determined by real-time RT-PCR. The excretion of 8-oxo-7,8-dihydro-oxoguanine (8-oxoGua) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in urine was measured by high performance liquid chromatography purification followed by gas chromatography with mass spectrometry. The morning following exposure to wood smoke the PBMC levels of SB were significantly decreased and the mRNA levels of hOGG1 significantly increased. FPG sites, hOGG1 activity, expression of hNUDT1 and hHO1, urinary excretion of 8-oxodG and 8-oxoGua did not change significantly. Our findings support that exposure to wood smoke causes systemic effects, although we could not demonstrate genotoxic effects, possibly explained by enhanced repair and timing of sampling.     

Proteomic changes in Debaryomyces hansenii upon exposure to NaCl stress

The proteome of the highly NaCl-tolerant yeast Debaryomyces hansenii was investigated by two-dimensional polyacrylamide gel electrophoresis (2D PAGE), and 47 protein spots were identified by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) followed by mass spectrometry (MS). The influence of NaCl on the D. hansenii proteome was investigated during the first 3 h of NaCl exposure. The rate of protein synthesis was strongly decreased by exposure to 8% and 12% (w/v) NaCl, as the average incorporation rates of l-[(35)S]methionine within the first 30 min after addition of NaCl were only 7% and 4% of the rate in medium without NaCl. In addition, the number of protein spots detected on 2D gels prepared from cells exposed to 8% and 12% (w/v) NaCl exceeded less than 28% of the number of protein spots detected on 2D gels prepared from cells without added NaCl. Several proteins were identified as being either induced or repressed upon NaCl exposure. The induced proteins were enzymes involved in glycerol synthesis/dissimilation and the upper part of glycolysis, whereas the repressed proteins were enzymes involved in the lower part of glycolysis, the route to the Krebs cycle, and the synthesis of amino acids. Furthermore, one heat shock protein (Ssa1p) was induced, whereas others (Ssb2p and Hsp60p) were repressed.     

Proteomic methodological recommendations for studies involving human plasma, platelets, and peripheral blood mononuclear cells

This study was designed to develop, optimize and validate protocols for blood processing prior to proteomic analysis of plasma, platelets and peripheral blood mononuclear cells (PBMC) and to determine analytical variation of a single sample of depleted plasma, platelet and PBMC proteins within and between four laboratories each using their own standard operating protocols for 2D gel electrophoresis. Plasma depleted either using the Beckman Coulter IgY-12 proteome partitioning kit or the Amersham albumin and IgG depletion columns gave good quality gels, but reproducibility appeared better with the single-use immuno-affinity column. The use of the Millipore Filter Device for protein concentration gave a 16% ( p < 0.005) higher recovery of protein in flow-through sample compared with acetone precipitation. The use of OptiPrep gave the lowest level of platelet contamination (1:0.8) during the isolation of PBMC from blood. Several proteins (among which are alpha-tropomyosin, fibrinogen and coagulation factor XIII A) were identified that may be used as biomarkers of platelet contamination in future studies. When identifying preselected spots, at least three out of the four centers found similar identities for 10 out of the 10 plasma proteins, 8 out of the 10 platelet proteins and 8 out of the 10 PBMC proteins. The discrepancy in spot identifications has been described before and may be explained by the mis-selection of spots due to laboratory-to-laboratory variation in gel formats, low scores on the peptide analysis leading to no or only tentative identifications, or incomplete resolution of different proteins in what appears as a single abundant spot. The average within-laboratory coefficient of variation (CV) for each of the matched spots after automatic matching using either PDQuest or ProteomWeaver software ranged between 18 and 69% for depleted plasma proteins, between 21 and 55% for platelet proteins, and between 22 and 38% for PBMC proteins. Subsequent manual matching improved the CV with on average between 1 and 16%. The average between laboratory CV for each of the matched spots after automatic matching ranged between 4 and 54% for depleted plasma proteins, between 5 and 60% for platelet proteins, and between 18 and 70% for PBMC proteins. This variation must be considered when designing sufficiently powered studies that use proteomics tools for biomarker discovery. The use of tricine in the running buffer for the second dimension appears to enhance the resolution of proteins especially in the high molecular weight range.     

Effect of metanil yellow and malachite green on DNA synthesis in N-nitrosodiethylamine induced preneoplastic rat livers

Metanil yellow (MY) and malachite green (MG) are textile dyes, which, despite the ban occurs unsrupulously as food colouring agents. Accordingly they constitute a serious public health hazard and are of sufficient environmental concern. We have earlier reported that both MY and MG have tumor enhancing effects on the development of hepatic preneoplastic lesions induced by N-nitrosodiethylamine in rats. In order to understand the possible mechanisms by which MY and MG enhance tumor development, in this study we have tested the effects of MY and MG on DNA synthesis and PCNA expression in preneoplastic hepatic lesions during N-nitrosodiethylamine (DEN) induced hepatocarcinogenesis in male Wistar (WR) rats. Rats were administered 200 ppm DEN through drinking water for a period of one month. Administration of DEN for a period of one month showed an upregulation of cell cycle regulatory proteins namely cyclin D1, CDK4, cyclin E and CDK2. Accordingly, in other experiments, the animals were further administered MY and MG for a period of one month following one month DEN treatment. The effects of MY and MG were monitored on the basis of cell proliferation markers--DNA synthesis and PCNA expression both by immunohistochemical and immunoblotting. Following DEN administration, MY, MG and PB showed stimulation of DNA synthesis and increased PCNA expression when compared with either the corresponding controls or only DEN treated animals. In the present study, enhancing effect of MY, MG and PB on the cell proliferation markers during DEN-induced hepatic preneoplasia in rats was observed.     

A Lower Degree of PBMC L1 Methylation in Women with Lower Folate Status May Explain the MTHFR C677T Polymorphism Associated Higher Risk of CIN in the US Post Folic Acid Fortification Era

Background

Studies in populations unexposed to folic acid (FA) fortification have demonstrated that MTHFR C677T polymorphism is associated with increased risk of higher grades of cervical intraepithelial neoplasia (CIN 2+). However, it is unknown whether exposure to higher folate as a result of the FA fortification program has altered the association between MTHFR C677T and risk of CIN, or the mechanisms involved with such alterations. The current study investigated the following in a FA fortified population: 1) The association between MTHFR C677T polymorphism and risk of CIN 2+; 2) The modifying effects of plasma folate concentrations on this association; and 3) The modifying effects of plasma folate on the association between the polymorphism and degree of methylation of long interspersed nucleotide elements (L1s), in peripheral blood mononuclear cell (PBMC) DNA, a documented biomarker of CIN risk.

Methods

The study included 457 US women diagnosed with either CIN 2+ (cases) or ≤ CIN 1 (non-cases). Unconditional logistic regression models were used to test the associations after adjusting for relevant risk factors for CIN.

Results

The 677CT/TT MTHFR genotypes were not associated with the risk of CIN 2+. Women with CT/TT genotype with lower folate, however, were more likely to be diagnosed with CIN 2+ compared to women with CT/TT genotype with higher folate (OR = 2.41, P = 0.030). Women with CT/TT genotype with lower folate were less likely to have a higher degree of PBMC L1 methylation compared to women with CT/TT genotype with higher folate (OR = 0.28, P = 0.017).

Conclusions

This study provides the first evidence that the MTHFR 677CT/TT genotype-associated lower degree of PBMC L1 methylation increases the risk of CIN 2+ in women in the US post-FA fortification era. Thus, even in the post-FA fortification era, not all women have adequate folate status to overcome MTHFR 677CT/TT genotype-associated lower degree of L1 methylation.     

Proteomic analysis of effect of hyperthermia on spermatogenesis in adult male mice

We characterized cellular and molecular mechanisms involved in spermatogenesis following short-term heat exposure of murine testis. For these studies, we utilized a proteomic approach with two-dimensional gel electrophoresis (2DE) analyses and mass spectroscopic identification of proteins with altered expression in mouse testes at different times after heat shock. We established a proteome reference map from 7-wk-old mouse testis linked to a federated proteome database. We used these tools to analyze quantitative variations in the tissue over a time course of 0.5, 2, 6, and 12 h following heat exposure. We separated 108 protein spots expressed differentially between the heat shock tissues and the control mouse testes. Of these spots, we identified 36 by comparing with the control reference map. We then focused on the heterogeneous nuclear ribonucleoproteins (hnRNPs) and the chaperonins containing t-complex polypeptide-1 (CCT). Further analysis in this heat-shocked model suggests numerous potential mechanisms for heat shock-induced spermatogenic disorder.     

Occult HCV or delayed viral clearance from lymphocytes of Chronic HCV genotype 3 patients after interferon therapy

Background

A recently discovered occult HCV entity reported by various investigators seems to be highly controversial. Especially, the clinical significance of these findings remains uncertain. For optimal outcome of antiviral therapy, investigation of occult HCV needs a broad-based probe in order to investigate the results of viral therapy and its host/viral interaction. The current study was aimed at determining the prevalence of occult HCV in peripheral blood lymphocytes of predominantly genotype 3 HCV-infected patients after completion of antiviral therapy and to investigate long term outcomes in the presence or absence of PBMC positivity.

Method

A total of 151 chronic, antiHCV and serum RNA-positive patients were enrolled in the study. Patients with a complete virological response at the end of treatment were screened for the presence of viral RNA in their PBMCs and were followed for up to one year for the presence of serum and PBMC viral genomic RNA.

Results

Out of 151 patients, 104 (70%) responded to the prescribed interferon treatment and showed viral-clearance from serum. These were screened for the presence of genomic RNA in their PBMCs. Sixteen samples were PBMC-positive for viral RNA at the end of treatment (EOT). All these patients had also cleared the virus from peripheral blood cells after the 6-12 month follow-up study.

Conclusion

True occult hepatitis C virus does not exist in our cohort. Residual viremia at the EOT stage merely reflects a difference in viral kinetics in various compartments that remains a target of immune response even after the end of antiviral therapy and is eventually cleared out at the sustained viral response (SVR).     

The human peripheral blood mononuclear cell proteome responds to a dietary flaxseed-intervention and proteins identified suggest a protective effect in atherosclerosis

Flaxseed is one of the richest sources of lignans that are converted to enterolactone by the intestinal microflora. Enterolactone has been suggested to be the prime active compound mediating atherosclerosis-protective effects that were shown for flaxseed. The effects of a 1-wk intervention with 0.4 g of flaxseed/kg body weight per day on enterolactone plasma levels in seven healthy men revealed that all participants (PAs) responded with enhanced enterolactone plasma levels. Proteome analysis of peripheral blood mononuclear cells (PBMC) from donors before, during, and after the intervention showed that flaxseed consumption affected significantly the steady-state levels of 16 proteins of which four were altered in a similar manner when blood mononuclear cells were exposed ex vivo to enterolactone. Enhanced levels of peroxiredoxin and reduced levels of the long-chain fatty acid beta-oxidation multienzyme complex may be taken as indicators of a reduced oxidative stress whereas reduced levels of glycoprotein IIIa/II could indicate improved protection from thrombotic and inflammatory processes. In conclusion, the blood mononuclear cell proteome responds to dietary flaxseed intake with changes in a number of atherosclerosis-relevant proteins that may be taken as biomarkers of exposure and some of these changes observed can be attributed to the action of the lignan metabolite enterolactone.     

Changes in the blood plasma protein composition in an experiment with seven-day dry immersion

This study was designed to track changes in the blood plasma proteome caused by exposure of healthy humans to dry immersion. The blood plasma specimens of five healthy volunteers aged 23–29 years obtained seven days before immersion, on day 7 of exposure in the immersion bath, and seven days after completion of the experiment were analyzed. After the extraction of major and the concentration of minor proteins, depleted blood plasma fractions were subjected to two-dimensional electrophoresis with the subsequent identification of significantly different protein spots with the method of mass-spectrometric analysis of peptide fragments. A significant change in intensity was observed for 25 protein spots with a coefficient of variation of >60%. Cluster analysis confirmed substantial changes in the blood plasma proteome in the period of readaptation of the body to the conditions of normal vital activity upon completion of immersion. On day 7 of readaptation, the apolipoprotein A-1, A-IV, and E concentrations were significantly higher compared to the baseline data and the measurements on day 7 of immersion. However, the levels of α-, β-fibrinogen, the complement C4B factor, and serum amyloid P were found to be lower.     

Effect of Maraviroc Intensification on HIV-1-Specific T Cell Immunity in Recently HIV-1-Infected Individuals

Background

The effect of maraviroc on the maintenance and the function of HIV-1-specific T cell responses remains unknown.

Methods

Subjects recently infected with HIV-1 were randomized to receive anti-retroviral treatment with or without maraviroc intensification for 48 weeks, and were monitored up to week 60. PBMC and in vitro-expanded T cells were tested for responses to the entire HIV proteome by ELISpot analyses. Intracellular cytokine staining assays were conducted to monitor the (poly)-functionality of HIV-1-specific T cells. Analyses were performed at baseline and week 24 after treatment start, and at week 60 (3 months after maraviroc discontinuation).

Results

Maraviroc intensification was associated with a slower decay of virus-specific T cell responses over time compared to the non-intensified regimen in both direct ex-vivo as well as in in-vitro expanded cells. The effector function profiles of virus-specific CD8⁺ T cells were indistinguishable between the two arms and did not change over time between the groups.

Conclusions

Maraviroc did not negatively impact any of the measured parameters, but was rather associated with a prolonged maintenance of HIV-1-specific T cell responses. Maraviroc, in addition to its original effect as viral entry inhibitor, may provide an additional benefit on the maintenance of virus-specific T cells which may be especially important for future viral eradication strategies.     

Reciprocal osteoblastic and osteoclastic modulation in co-cultured MG63 osteosarcoma cells and human osteoclast precursors

Osteosarcoma is usually associated with a disturbed bone metabolism. The aim of this work was to characterize the reciprocal interactions between MG63 osteosarcoma cells and osteoclasts, in a co-culture system. Co-cultures were characterized throughout 21 days for the osteoclastogenic response and the expression of osteoblastic markers. Monocultures of MG63 cells and peripheral blood mononuclear cell (PBMC) and co-cultures of PBMC + human bone marrow cells (hBMC) were also performed. Compared to PBMC cultures, co-cultures yielded significantly increased gene expression of osteoclast-related markers, tartarate-acid resistant phosphatase (TRAP) activity, TRAP-positive multinucleated cells, cells with actin rings and vitronectin receptors (VNR) and calcitonin receptors (CTR) and calcium phosphate resorbing ability. Results showed that the development of functional osteoclasts required a very low number of MG63 cells, suggesting a high osteoclastogenic-triggering capacity of this cell line. Subjacent mechanisms involved the pathways MEK and NF-kB, although with a lower relevance than that observed on PBMC monocultures or co-cultures of hBMC + PBMC; PGE2 production also had a contribution. Compared to MG63 cell monocultures, the co-culture expressed lower levels of COL1 and ALP, and higher levels of BMP-2, suggesting that PBMC also modulated the osteoblastic behavior. While M-CSF appeared to be involved in the osteoclastogenic response on the MG63 + PBMC co-cultures, RANKL does not seem to be a key player in the process. On the other hand, sphingosine-1-phosphate production might contribute to the modulation of the osteoblastic behavior. Results suggest that the reciprocal modulation between osteosarcoma and osteoclastic cells might contribute to the disturbed bone metabolism associated with bone tumors.     

Application of proteomics for fast identification of species-specific peptides from marine species

In this work, a novel approach based on proteomics is applied for the analysis of the three European marine mussel species: Mytilus edulis (ME), Mytilus galloprovincialis (MG) and Mytilus trossulus (MT), which are of interest in biotechnology and food industry. The proteomes of these species are poorly described in databases, are difficult to diagnose, and have a controversial taxonomy, To characterise species-specific peptides, we compared 51 matrix-assisted laser desorption/ioization-time of flight peptide mass maps generated from 6 random selected prominent spots derived from the two-dimensional electrophoresis analysis of foot protein extracts from several individuals. Minor species-specific differences in the peptide maps were detected in only one of the spots, corresponding to tropomyosin. Two peptides were unique to ME and MG individuals, whereas another peptide was present only in MT individuals. The sequence of these peptides was characterised by, nanoelectrospray ionization-ion trap (nanoESI-IT) tandem mass spectrometry (MS/MS) analysis followed by database searching and de novo sequence interpretation. We detected a single T to D amino acid substitution in MT tropomyosin. Unambiguous and highly-specific species identification was then demonstrated by analysing peptide extracts from tropomyosin spots by micro high-performande liquid chromatography (microHPL) ESI-IT mass spectrometry using the selected ion monitoring configuration, focused on these peptides, in continuous MS/MS operation. Our results suggest that proteomics may be successfully applied for the identification of species whose proteome is not present in databases.     

Methylglyoxal mediates adipocyte proliferation by increasing phosphorylation of Akt1

Methylglyoxal (MG) is a highly reactive metabolite physiologically presented in all biological systems. The effects of MG on diabetes and hypertension have been long recognized. In the present study, we investigated the potential role of MG in obesity, one of the most important factors to cause metabolic syndrome. An increased MG accumulation was observed in the adipose tissue of obese Zucker rats. Cell proliferation assay showed that 5-20 μM of MG stimulated the proliferation of 3T3-L1 cells. Further study suggested that accumulated-MG stimulated the phosphorylation of Akt1 and its targets including p21 and p27. The activated Akt1 then increased the activity of CDK2 and accelerated the cell cycle progression of 3T3-L1 cells. The effects of MG were efficiently reversed by advanced glycation end product (AGE) breaker alagebrium and Akt inhibitor SH-6. In summary, our study revealed a previously unrecognized effect of MG in stimulating adipogenesis by up-regulation of Akt signaling pathway and this mechanism might offer a new approach to explain the development of obesity.     

Human T lymphocyte activation by monoclonal antibodies; OKT3, but not UCHT1, triggers mitogenesis via an interleukin 2-dependent mechanism

OKT3 and UCHT1 monoclonal antibodies, which recognize the same human T cell surface antigen, induce proliferation in T lymphocytes. In this report, we compared the mechanism by which these antibodies trigger DNA synthesis in human peripheral blood mononuclear cell (PBMC) cultures. Whereas PBMC from all donors tested were mitogenically inducible by OKT3, cells from only 25 of 40 donors were responsive to UCHT1 . UCHT1 treatment of PBMC from responders, but not from nonresponders, resulted in the expression by T cells of membrane binding sites reactive with anti-Tac monoclonal antibody, which specifies the human interleukin 2 (IL 2) receptor. UCHT1 -induced PBMC supernatants from nonresponders, but unexpectedly, also from responders, contained no measurable IL 2 activity. In keeping with this finding, anti-Tac monoclonal antibody failed to suppress UCHT1 -triggered [3H]thymidine incorporation into PBMC from responsive donors. By contrast, OKT3 treatment of PBMC from all donors led to the emergence of IL 2 receptors, and substantial IL 2 production, and the resultant DNA synthesis was inhibitable by anti-Tac antibody. These data indicate that the interaction of OKT3 and UCHT1 monoclonal antibodies with the same T cell structure leads to the induction of proliferation via two different mechanisms: one dependent on the availability of IL 2 (OKT3) and one independent on the production and processing of this lymphokine ( UCHT1 ). PBMC unresponsiveness to UCHT1 could therefore not be related to a dysfunction in IL 2 synthesis or IL 2 receptor display.     

Molecular basis underlying the biological effects elicited by extremely low-frequency magnetic field (ELF-MF) on neuroblastoma cells

Extremely low-frequency magnetic fields (ELF-MFs) may affect human health because of the possible associations with leukemia but also with cancer, cardiovascular, and neurological disorders. In the present work, human SH-SY5Y neuroblastoma cells were exposed to a 50 Hz, 1 mT sinusoidal ELF-MF at three different times, that is, 5 days (T5), 10 days (T10), and 15 days (T15) and then the effects of ELF-MF on proteome expression and biological behavior were investigated. Through comparative analysis between treated and control samples, we analyzed the proteome changes induced by ELF-MF exposure. Nine new proteins resolved in sample after a 15-day treatment were involved in a cellular defense mechanism and/or in cellular organization and proliferation such as peroxiredoxin isoenzymes (2, 3, and 6), 3-mercaptopyruvate sulfurtransferase, actin cytoplasmatic 2, t-complex protein subunit beta, ropporin-1A, and profilin-2 and spindlin-1. Our results indicated that ELF-MFs exposure altered the proliferative status and other important cell biology-related parameters, such as cell growth pattern, and cytoskeletal organization. These findings support our hypothesis that ELF radiation could trigger a shift toward a more invasive phenotype.     

Analysis of gene expression in two human-derived cell lines exposed in vitro to a 1.9 GHz pulse-modulated radiofrequency field

There is considerable controversy surrounding the biological effects of radiofrequency (RF) fields, as emitted by mobile phones. Previous work from our laboratory has shown no effect related to the exposure of 1.9 GHz pulse-modulated RF fields on the expression of 22,000 genes in a human glioblastoma-derived cell-line (U87MG) at 6 h following a 4 h RF field exposure period. As a follow-up to this study, we have now examined the effect of RF field exposure on the possible expression of late onset genes in U87MG cells after a 24 h RF exposure period. In addition, a human monocyte-derived cell-line (Mono-Mac-6, MM6) was exposed to intermittent (5 min ON, 10 min OFF) RF fields for 6 h and then gene expression was assessed immediately after exposure and at 18 h postexposure. Both cell lines were exposed to 1.9 GHz pulse-modulated RF fields for 6 or 24 h at specific absorption rates (SARs) of 0.1-10.0 W/kg. In support of our previous results, we found no evidence that nonthermal RF field exposure could alter gene expression in either cultured U87MG or MM6 cells, relative to nonirradiated control groups. However, exposure of both cell-lines to heat-shock conditions (43 degrees C for 1 h) caused an alteration in the expression of a number of well-characterized heat-shock proteins.