Beryllium-specific immune response in primary cells from healthy individuals

Hydrogen sulfide alleviates beryllium sulfate-induced ferroptosis and ferritinophagy in 16HBE cells

Beryllium sulfate (BeSO₄ ) can result to lung injuries, such as leading to lipid peroxidation and autophagy, and the treatment of beryllium disease has not been well improved. Ferroptosis is a regulated cell death process driven by iron-dependent and lipid peroxidation, while ferritinophagy is a process mediated by nuclear receptor coactivator 4 (NCOA4), combined with ferritin heavy chain 1 (FTH1) degradation and release Fe²⁺ , which regulated intracellular iron metabolism and ferroptosis. Hydrogen sulfide (H₂ S) has the effects of antioxidant, antiautophagy, and antiferroptosis. This study aimed to investigate the effect of H₂ S on BeSO₄ -induced ferroptosis and ferritinophagy in 16HBE cells and the underlying mechanism. In this study, BeSO₄ -induced 16HBE cell injury model was established based on cellular level and pretreated with deferoxamine (DFO, a ferroptosis inhibitor), sodium hydrosulfide (NaHS, a H₂ S donor), or NCOA4 siRNA and, subsequently, performed to detect the levels of lipid peroxidation and Fe²⁺ and the biomarkers of ferroptosis and ferritinophagy. More importantly, our research found that DFO, NaHS, or NCOA4 siRNA alleviated BeSO₄ -induced ferroptosis and ferritinophagy by decreasing the accumulation of Fe²⁺ and lipid peroxides. Furthermore, the relationship between ferroptosis, ferritinophagy, H₂ S, and beryllium disease is not well defined; therefore, our research is innovative. Overall, our results provided a new theoretical basis for the prevention and treatment of beryllium disease and suggested that the application of H₂ S, blocking ferroptosis, and ferritinophagy may be a potential therapeutic direction for the prevention and treatment of beryllium disease.

Beryllium-induced lung disease exhibits expression profiles similar to sarcoidosis

A subset of beryllium-exposed workers develop beryllium sensitisation (BeS) which precedes chronic beryllium disease (CBD). We conducted an in-depth analysis of differentially expressed candidate genes in CBD.We performed Affymetrix GeneChip 1.0 ST array analysis on peripheral blood mononuclear cells (PBMCs) from 10 CBD, 10 BeS and 10 beryllium-exposed, nondiseased controls stimulated with BeSO4 or medium. The differentially expressed genes were validated by high-throughput real-time PCR in this group and in an additional group of cases and nonexposed controls. The functional roles of the top candidate genes in CBD were assessed using a pharmacological inhibitor. CBD gene expression data were compared with whole blood and lung tissue in sarcoidosis from the Gene Expression Omnibus.We confirmed almost 450 genes that were significantly differentially expressed between CBD and controls. The top enrichment of genes was for JAK (Janus kinase)-STAT (signal transducer and activator of transcription) signalling. A JAK2 inhibitor significantly decreased tumour necrosis factor-α and interferon-γ production. Furthermore, we found 287 differentially expressed genes overlapped in CBD/sarcoidosis. The top shared pathways included cytokine-cytokine receptor interactions, and Toll-like receptor, chemokine and JAK-STAT signalling pathways.We show that PBMCs demonstrate differentially expressed gene profiles relevant to the immunnopathogenesis of CBD. CBD and sarcoidosis share similar differential expression of pathogenic genes and pathways.

Beryllium increases the CD14(dim)CD16+ subset in the lung of chronic beryllium disease

CD14^dimCD16+ and CD14^brightCD16+ cells, which compose a minor population of monocytes in human peripheral blood mononuclear cells (PBMC), have been implicated in several inflammatory diseases. The aim of this study was to investigate whether this phenotype was present as a subset of lung infiltrative alveolar macrophages (AMs) in the granulomatous lung disease, chronic beryllium disease (CBD). The monocytes subsets was determined from PBMC cells and bronchoalveolar lavage (BAL) cells from CBD, beryllium sensitized Non-smoker (BeS-NS) and healthy subjects (HS) using flow cytometry. The impact of smoking on the AMs cell phenotype was determined by using BAL cells from BeS smokers (BeS-S). In comparison with the other monocyte subpopulations, CD14^dimCD16+ cells were at decreased frequency in PBMCs of both BeS-NS and CBD and showed higher HLA-DR expression, compared to HS. The AMs from CBD and BeS-NS demonstrated a CD14^dimCD16+phenotype, while CD14^brightCD16+ cells were found at increased frequency in AMs of BeS, compared to HS. Fresh AMs from BeS-NS and CBD demonstrated significantly greater CD16, CD40, CD86 and HLA-DR than HS and BeS-S. The expression of CD16 on AMs from both CBD and BeS-NS was downregulated significantly after 10μM BeSO₄ stimulation. The phagocytic activity of AMs decreased after 10μM BeSO₄ treatment in both BeS-NS and CBD, although was altered or reduced in HS and BeS-S. These results suggest that Be increases the CD14^dimCD16+ subsets in the lung of CBD subjects. We speculate that Be-stimulates the compartmentalization of a more mature CD16+ macrophage phenotype and that in turn these macrophages are a source of Th1 cytokines and chemokines that perpetuate the Be immune response in CBD. The protective effect of cigarette smoking in BeS-S may be due to the low expression of co-stimulatory markers on AMs from smokers as well as the decreased phagocytic function.

p38 Mitogen-Activated Protein Kinase in beryllium-induced dendritic cell activation

Dendritic cells (DC) play a role in the regulation of immune responses to haptens, which in turn impact DC maturation. Whether beryllium (Be) is able to induce DC maturation and if this occurs via the MAPK pathway is not known. Primary monocyte-derived DCs (moDCs) models were generated from Be non-exposed healthy volunteers as a non-sensitized cell model, while PBMCs from BeS (Be sensitized) and CBD (chronic beryllium disease) were used as disease models. The response of these cells to Be was evaluated. The expression of CD40 was increased significantly (p<0.05) on HLA-DP Glu69+ moDCs after 100 μM BeSO₄-stimulation. BeSO₄ induced p38MAPK phosphorylation, while IκB-α was degraded in Be-stimulated moDCs. The p38 MAPK inhibitor SB203580 blocked Be-induced NF-κB activation in moDCs, suggesting that p38MAPK and NF-κB are dependently activated by BeSO₄. Furthermore, in BeS and CBD subjects, SB203580 downregulated Be-stimulated proliferation in a dose-dependent manner, and decreased Be-stimulated TNF-α and IFNγ cytokine production. Taken together, this study suggests that Be-induces non-sensitized Glu69+ DCs maturation, and that p38MAPK signaling is important in the Be-stimulated DCs activation as well as subsequent T cell proliferation and cytokine production in BeS and CBD. In total, the MAPK pathway may serve as a potential therapeutic target for human granulomatous lung diseases.

Effects of beryllium on human serum immunoglobulin and lymphocyte subpopulation

To investigate the effects of short-term exposure of beryllium on the human immune system, the proportion of T-lymphocytes such as CD3+, CD4+, CD8+, CD95, and NK cells, andthe proportion of B cells and TNFα level in peripheral blood and immunoglobulins in the serum of 43 exposed workers and 34 healthy control subjects were studied. External exposure to beryllium was measured by atomic absorption spectrometer as recommended by the NIOSH analytical method 7300. T lymphocyte subpopulation analysis was carried out with flow cytometer. The working duration of exposed workers was less than 3 months and the mean ambient beryllium level was 3.4 μg/m(3), 112.3 μg/m(3), and 2.3 μg/m(3) in molding (furnace), deforming (grinding), and sorting processes, respectively (cited from Kim et al., 2008). However, ambient beryllium level after process change was non-detectable (< 0.1 μg/m(3)). The number of T lymphocytes and the amount of immunoglobulins in the beryllium-exposed workers and control subjects were not significantly different, except for the total number of lymphocytes and CD95 (APO1/FAS). The total number of lymphocytes was higher in the beryllium-exposed individuals than in the healthy control subjects. Multiple logistic regression analysis showed lymphocytes to be affected by beryllium exposure (odd ratio = 7.293; p < 0.001). These results show that short-term exposure to beryllium does not induce immune dysfunction but is probably associated with lymphocytes proliferation.

Search for chronic beryllium disease among sarcoidosis patients in Ontario, Canada

Chronic beryllium disease (CBD) is clinically similar to other granulomatous diseases such as sarcoidosis. It is often misdiagnosed if a thorough occupational history is not taken. When appropriate, a beryllium lymphocyte proliferation tests (BeLPT) need to be performed. We aimed to search for CBD among currently diagnosed pulmonary sarcoidosis patients and to identify the occupations and exposures in Ontario leading to CBD. Questionnaire items included work history and details of possible exposure to beryllium. Participants who provided a history of previous work with metals underwent BeLPTs and an ELISPOT on the basis of having a higher pretest probability of CBD. Among 121 sarcoid patients enrolled, 87 (72%) reported no known previous metal dust or fume exposure, while 34 (28%) had metal exposure, including 17 (14%) with beryllium exposure at work or home. However, none of these 34 who underwent testing had positive test results. Self-reported exposure to beryllium or metals was relatively common in these patients with clinical sarcoidosis, but CBD was not confirmed using blood assays in this population.

Chronic beryllium disease: an updated model interaction between innate and acquired immunity

During the last decade, there have been concerted efforts to reduce beryllium (Be) exposure in the workplace and thereby reduce potential cases of this occupational lung disorder. Despite these efforts, it is estimated that there are at least one million Be-exposed individuals in the U.S. who are potentially at risk for developing chronic beryllium disease (CBD). Previously, we reviewed the current CBD literature and proposed that CBD represents a model interaction between innate and acquired immunity (Sawyer et al., Int Immunopharmacol 2:249-261, 2002). We closed this review with a section on "future directions" that identified key gaps in our understanding of the pathogenesis of CBD. In the intervening period, progress has been made to fill in some of these gaps, and the current review will provide an update on that progress. Based on recent findings, we provide a new hypothesis to explain how Be drives sustained chronic inflammation and granuloma formation in CBD leading to progressive compromised lung function in CBD patients. This paradigm has direct implications for our understanding of the development of an immune response to Be, but is also likely applicable to other immune-mediated lung diseases of known and unknown etiology.

Beryllium alters lipopolysaccharide-mediated intracellular phosphorylation and cytokine release in human peripheral blood mononuclear cells

Beryllium exposure in susceptible individuals leads to the development of chronic beryllium disease, a lung disorder marked by release of inflammatory cytokine and granuloma formation. We have previously reported that beryllium induces an immune response even in blood mononuclear cells from healthy individuals. In this study, we investigate the effects of beryllium on lipopolysaccharide-mediated cytokine release in blood mononuclear and dendritic cells from healthy individuals. We found that in vitro treatment of beryllium sulfate inhibits the secretion of lipopolysaccharide-mediated interleukin 10, while the release of interleukin 1beta is enhanced. In addition, not all lipopolysaccharide-mediated responses are altered, as interleukin 6 release in unaffected upon beryllium treatment. Beryllium sulfate-treated cells show altered phosphotyrosine levels upon lipopolysaccharide stimulation. Significantly, beryllium inhibits the phosphorylation of signal transducer and activator of transducer 3, induced by lipopolysaccharide. Finally, inhibitors of phosphoinositide-3 kinase mimic the effects of beryllium in inhibition of interleukin 10 release, while they have no effect on interleukin 1beta secretion. This study strongly suggests that prior exposures to beryllium could alter host immune responses to bacterial infections in healthy individuals, by altering intracellular signaling.

Mercury induces an unopposed inflammatory response in human peripheral blood mononuclear cells in vitro

BACKGROUND

The human immune response to mercury is not well characterized despite the body of evidence that suggests that Hg can modulate immune responses, including the induction of autoimmune disease in some mouse models. Dysregulation of cytokine signaling appears to play an important role in the etiology of Hg-induced autoimmunity in animal models.

OBJECTIVES

In this study, we systematically investigated the human immune response to Hg in vitro in terms of cytokine release.

METHODS

Human peripheral blood mononuclear cells (PBMCs) were isolated from 20 volunteers who donated blood six separate times. PBMCs were cultured with lipopolysaccharide and concentrations of mercuric chloride (HgCl(2)) up to 200 nM. Seven cytokines representing important pathways in physiologic and pathologic immune responses were measured in supernatants. We used multilevel models to account for the intrinsic clustering in the cytokine data due to experimental design.

RESULTS

We found a consistent increase in the release of the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha, and concurrent decrease in release of the antiinflammatory cytokines interleukin 1-receptor antagonist (IL-1Ra) and IL-10 in human PBMCs treated with subcytotoxic concentrations of HgCl(2). IL-4, IL-17, and interferon-gamma increased in a concentration-response manner. These results were replicated in a second, independently recruited population of 20 different volunteers.

CONCLUSIONS

Low concentrations of HgCl(2) affect immune function in human cells by dysregulation of cytokine signaling pathways, with the potential to influence diverse health outcomes such as susceptibility to infectious disease or risk of autoimmunity.

Recent advances in understanding the biomolecular basis of chronic beryllium disease: a review

In this review we summarize the work conducted over the past decade that has advanced our knowledge of pulmonary diseases associated with exposure to beryllium that has provided a molecular-based understanding of the chemistry, immunopathology, and immunogenetics of beryllium toxicity. Beryllium is a strong and lightweight metal that generates and reflects neutrons, resists corrosion, is transparent to X-rays, and conducts electricity. Beryllium is one of the most toxic elements on the periodic table, eliciting in susceptible humans (a) an allergic immune response known as beryllium sensitization (BeS); (b) acute beryllium disease, an acutely toxic, pneumonitis-like lung condition resulting from exposure to high beryllium concentrations that are rarely seen in modern industry; and (c) chronic beryllium disease (CBD) following either high or very low levels of exposure. Because of its exceptional strength, stability, and heat-absorbing capability, beryllium is used in many important technologies in the modern world. In the early 1940s, beryllium was recognized as posing an occupational hazard in manufacturing and production settings. Although acute beryllium disease is now rare, beryllium is an insidious poison with a latent toxicity and the risk of developing CBD persists. Chronic beryllium disease-a systemic granulomatous lung disorder caused by a specific delayed immune response to beryllium within a few months to several decades after exposure-has been called the "unrecognized epidemic". Although not a disease in itself, BeS, the innate immune response to beryllium identified by an abnormal beryllium lymphocyte proliferation test result, is a population-based predictor of CBD. Genetic susceptibility to CBD is associated with alleles of the major histocompatibility gene, human leukocyte antigen DP (HLA-DP) containing glutamic acid at the 69th position of the beta chain (HLA-DPbeta-E69). Other genes are likely to be involved in the disease process, and research on this issue is in progress. The current Occupational Safety & Health Administration permissible exposure limit of 2 microg/m3 has failed to protect workers from BeS/CBD. As a safe exposure limit that will not lead to BeS or CBD has not yet been determined, the realization that the risk of CBD persists has led to a renaissance in research on the effects of the metal on human health. Current data support further reductions in exposure levels to help minimize the incidence of CBD. Steps that would directly impact both the power of epidemiologic studies and the cost of surveillance would be to develop and validate improved screening and diagnostic tests, and to identify more genetic factors that affect either sensitization or disease process. The major focus of this review is the recent research on the cellular and molecular basis of beryllium sensitization and disease, using a multidisciplinary approach of bioinorganic chemistry and immunology. First we present a historical background of beryllium exposure and disease, followed by occurrence of beryllium in the environment, toxicokinetics, biological effects, beryllium lung disease, and other human health effects.

The bioinorganic chemistry and associated immunology of chronic beryllium disease

Chronic beryllium disease (CBD) is a debilitating, incurable, and often fatal disease that is caused by the inhalation of beryllium particulates. The growing use of beryllium in the modern world, in products ranging from computers to dental prosthetics (390 tons of beryllium in the US in the year 2000) necessitates a molecular based understanding of the disease in order to prevent and cure CBD. We have investigated the molecular basis of CBD at Los Alamos National Laboratory during the past six years, employing a multidisciplinary approach of bioinorganic chemistry and immunology. The results of this work, including speciation, inhalation and dissolution, and immunology will be discussed.

Activation pathways implicate anti-HLA-DP and anti-LFA-1 antibodies as lead candidates for intervention in chronic berylliosis

CD4(+) T cells play a key role in granulomatous inflammation in the lung of patients with chronic beryllium disease. The goal of this study was to characterize activation pathways of beryllium-responsive bronchoalveolar lavage (BAL) CD4(+) T cells from chronic beryllium disease patients to identify possible therapeutic interventional strategies. Our results demonstrate that in the presence of APCs, beryllium induced strong proliferation responses of BAL CD4(+) T cells, production of superoptimal concentrations of secreted proinflammatory cytokines, IFN-gamma, TNF-alpha,and IL-2, and up-regulation of numerous T cell surface markers that would promote T-T Ag presentation. Ab blocking experiments revealed that anti-HLA-DP or anti-LFA-1 Ab strongly reduced proliferation responses and cytokine secretion by BAL CD4(+) T cells. In contrast, anti-HLA-DR or anti-OX40 ligand Ab mainly affected beryllium-induced proliferation responses with little impact on cytokines other than IL-2, thus implying that nonproliferating BAL CD4(+) T cells may still contribute to inflammation. Blockade with CTLA4-Ig had a minimal effect on proliferation and cytokine responses, confirming that activation was independent of B7/CD28 costimulation. These results indicate a prominent role for HLA-DP and LFA-1 in BAL CD4(+) T cell activation and further suggest that specific Abs to these molecules could serve as a possible therapy for chronic beryllium disease.