The environmental pollutant BDE-47 modulates immune responses in invitro and in vivo murine models.

2,2',4,4'-tetra-bromodiphenyl ether (BDE-47) is widespread in the environment and biological samples. Its association with health risks is an increasing concern, yet information on BDE-47 immunotoxicity remains limited. This study investigated the impact of BDE-47 on innate and adaptive immune responses through in vitro and in vivo approaches. BDE-47's capacity to directly induce cell responses and modulate responses induced by known stimuli was studied in vitro using the RAW 264.7 murine macrophage cell line and spleen-derived lymphocytes, and in vivo using keyhole limpet hemocyanin (KLH)-immunized BALB/c mice orally administered (28 d) at dose levels (7.5, 15.0 and 30 mg/kg/bw/d) derived from relevant toxicokinetic data from rodent models. RAW 264.7 cells stimulated with lipopolysaccharide (LPS) and exposed to BDE-47 exhibited unchanged cell viability but decreased release of interleukin (IL)-6. Primary splenocytes from naïve mice stimulated with anti-CD3/anti-CD28 antibodies and exposed to BDE-47 showed a significant decrease of IL-17 A and IFNγ production. In vivo data showed that BDE-47 significantly reduced the KLH-specific antibody response. A generally decreasing trend of IFNγ, IL-10 and IL-5 production was observed after in vitro antigen-specific restimulation of spleen cells. Histopathological effects on liver, spleen, small intestine and thyroid were detected at the highest dose in the absence of general toxicity. In addition, the expression of Mm_mir155 and Mm_let7a was induced in livers of exposed mice. The data obtained in this study suggest that exposure to BDE-47 may perturb innate and adaptive immune responses, thus possibly decreasing resistance to bacterial and viral infections.

Effects of sub-chronic oral exposure to pyrogenic synthetic amorphous silica (NM-203) in male and female Sprague-Dawley rats: focus on reproductive systems.

Synthetic amorphous silica (SAS) consists of agglomerates and aggregates of primary particles in the nanorange (<100 nm) and it is the E551 authorized food additive. The potential risks for human health associated to dietary exposure to SAS are not completely assessed; in particular, data on male and female reproductive systems are lacking. A 90-day oral toxicity study with pyrogenic SAS nanomaterial NM-203 was carried out on the basis of the OECD test guideline 408 in the frame of the NANoREG project. Adult Sprague-Dawley rats of both sexes were orally treated for 90 days with 0, 2, 5, 10, 20 and 50 mg SAS/kg bw per day. Dose levels were selected to be as close as possible to the expected human exposure to food additive E551. The present paper provides specific information on potential effects on male and female reproductive systems, through the evaluation of serum biomarkers, sperm count, histopathological analysis of testis, epididymis, ovary and uterus and real-time PCR on uterus; potential genotoxic alterations were evaluated by comet assay on testis, sperm and ovary. NM-203 did not induce histophatological and genotoxic effects in male reproductive system. In female rats, ovary is not target of NM-203 and only tissue-specific effects on uterus were recorded up to 10 mg/kg bw per day. To our best knowledge, this is the first study providing data on male and female reproductive systems after long-term, repeated oral exposure at dose levels close to dietary human exposure, which identifies a limited concern only for female reproductive health.

Use of a common European approach for nanomaterials' testing to support regulation: a case study on titanium and silicon dioxide representative nanomaterials.

The European Union (EU) continuously takes ensuring the safe use of manufactured nanomaterials (MNMs) in consumer products into consideration. The application of a common approach for testing MNMs, including the use of optimized protocols and methods' selection, becomes increasingly important to obtain reliable and comparable results supporting the regulatory framework. In the present study, we tested four representative MNMs, two titanium dioxides (NM100 and NM101) and two silicon dioxides (NM200 and NM203), using the EU FP7-NANoREG approach, starting from suspension and dispersion preparations, through to their characterization and final evaluation of biological effects. MNM dispersions were prepared following a refined NANOGENOTOX protocol and characterized by dynamic light scattering (DLS) in water/bovine serum albumin and in media used for in vitro testing. Potential genotoxic effects were evaluated on human bronchial BEAS-2B cells using micronucleus and Comet assays, and pro-inflammatory effects by cytokines release. Murine macrophages RAW 264.7 were used to detect potential innate immune responses using two functional endpoints (pro-inflammatory cytokines and nitric oxide [NO] production). The interaction of MNMs with RAW 264.7 cells was studied by electron microscopy. No chromosomal damage and slight DNA damage and an oxidative effect, depending on MNMs, were observed in bronchial cells. In murine macrophages, the four MNMs directly induced tumor necrosis factor α or interleukin 6 secretion, although at very low levels; lipopolysaccharide-induced NO production was significantly decreased by the titania and one silica MNM. The application of this approach for the evaluation of MNM biological effects could be useful for both regulators and industries.

In vitro exposure to 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) impairs innate inflammatory response.

Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants that are added to numerous products to prevent accidental fires. PBDEs are present in the environment and they bio-accumulate in human and animal tissues. Recently, their presence has been correlated to several pathologies but little is known about their effect on the human innate immune system activity. In this study we investigated the effect of the congener 2,2',4,4'-Tetrabromodiphenyl ether (PBDE-47) on the functional activity of the THP-1 human macrophages cell line and on ex vivo freshly isolated human basophils. Cytotoxicity and genotoxicity studies showed that PBDE-47 was able to induce toxic effects on the THP-1 cell line viability at concentrations ≥25 µM. Immune function of THP-1 was studied after stimulation with bacterial lipopolysaccharide (LPS) and PBDE-47 exposure at concentrations granting macrophage viability. Two dimensional electrophoresis showed modification of the proteome in the 3 µM PBDE-47 treated sample and Real Time PCR and ELISA demonstrated a statistically significant reduction in the expression of IL-1ß, IL-6 and TNF-α cytokines. Furthermore, PBDE-47 was able to perturbate genes involved in cell motility upregulating CDH-1 and downregulating MMP-12 expressions. Finally, basophil activation assay showed reduced CD63 activation in PBDE-47 treated samples. In conclusion, our study demonstrated that PBDE-47 may perturb the activities of cells involved in innate immunity dampening the expression of macrophage pro-inflammatory cytokines (IL-1ß, IL-6 and TNF-α) and genes involved in cell motility (MMP-12 and E-cadherin) and interfering with basophil activation suggesting that this compound can impair innate immune response.

Voacamine modulates the sensitivity to doxorubicin of resistant osteosarcoma and melanoma cells and does not induce toxicity in normal fibroblasts.

In previous studies it has been demonstrated that the plant alkaloid voacamine (1), used at noncytotoxic concentrations, enhanced the cytotoxicity of doxorubicin and exerted a chemosensitizing effect on cultured multidrug-resistant (MDR) U-2 OS-DX osteosarcoma cells. The in vitro investigations reported herein gave the following results: (i) the chemosensitizing effect of 1, in terms of drug accumulation and cell survival, was confirmed using SAOS-2-DX cells, another MDR osteosarcoma cell line; (ii) compound 1 enhanced the cytotoxic effect of doxorubicin also on the melanoma cell line Me30966, intrinsically drug resistant and P-glycoprotein-negative; (iii) at the concentrations used to sensitize tumor cells, 1 was not cytotoxic to normal cells (human fibroblasts). These findings suggest possible applications of voacamine (1) in integrative oncologic therapies against resistant tumors.

Prevalence of self-perceived allergic diseases and risk factors in Italian adolescents.

The aim of the study was to assess the symptoms prevalence of allergic diseases in a population of 11-15 yr old schoolchildren, to evaluate the associations between asthma and other symptoms and identify risk factors for asthma, rhinitis and eczema syndromes. A sample of 481 students was studied using an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Prevalence of different kind of self-reported symptoms was calculated. Using a logistic regression approach, we tried to identify risk factors for three syndromes - rhinitis, eczema and asthma. The highest and the lowest prevalence rates of self-reported symptoms were recorded for rhinitis (43.6%) and for eczema (8.1%), respectively. The prevalence of asthma was 15.7%. Univariate analysis showed a mutual association between wheeze and rhinitis symptoms. Multivariate logistic regression model for eczema syndrome revealed female gender as a significant risk factor. The polytomic logistic multivariate regression revealed female gender and family history of allergy as significant risk factors for rhinitis syndrome only, and maternal smoking and familial allergy for rhinitis and asthma together. In particular, familial allergy yields a 400% higher chance of developing asthma and rhinitis together. The synergistic effect of familial allergy on rhinitis and asthma syndromes suggests the implementation of preventive measures in children with family history of these diseases.

CTLA-4 regulates allergen response by modulating GATA-3 protein level per cell.

T helper type 2 (Th2) cell differentiation requires the expression of GATA-3, a transcription factor that allows transcriptional activation of Th2 cytokine genes through chromatin remodelling. We investigated the role of the negative costimulatory receptor cytotoxic T-lymphocyte antigen 4 (CTLA-4) in the regulation of GATA-3 expression, Th2 differentiation and immunoglobulin production during the immune response to allergens. BALB/c mice were immunized with a recombinant major allergenic component of Parietaria judaica pollen, rPar j I, and treated with blocking anti-CTLA-4 or control antibodies. Results showed that in vivo CTLA-4 blockade enhanced the Par j I-specific immunoglobulin E (IgE) serum level. In contrast, Par j I-specific IgG2a serum level was reduced, suggesting that CTLA-4 blockade skewed immunoglobulin production towards interleukin-4 (IL-4) -dependent immunoglobulin isotypes. Consistently, CTLA-4 blockade increased the frequency of Par j I-specific Th2 cells but not Th1 cells, as well as IL-4 and IL-5 but not interferon-gamma production. Our data also showed that CTLA-4 blockade enhanced the GATA-3 : T-bet messenger RNA ratio. Interestingly, in vivo CTLA-4 blockade did not increase the frequency of GATA-3 protein-expressing cells. In contrast, it enhances GATA-3 protein level per cell. Further, in vitro results show that the anti-CTLA-4 monoclonal antibody, by competing with CD80 for CTLA-4 binding, induced an enhancement in the frequency of IL-4-producing cells that correlates with the increase in GATA-3 protein level per cell. In conclusion, CTLA-4, by affecting the level of GATA-3 per cell, contributes to keeping this factor under the threshold required to become a Th2 effector cell. Consequently, it affects IgE/IgG2a production and contributes to the outcome of allergen-specific immune responses.