Arsenic trioxide, a potent inhibitor of NF-kappaB, abrogates allergen-induced airway hyperresponsiveness and inflammation

Meta-analysis of TLR4 pathway-related protein alterations induced by arsenic exposure

Arsenic is a toxic metal, which ultimately leads to cell apoptosis. TLR4 signaling pathway played a key role in immunomodulatory. Therefore, alterations in related proteins on the TLR4 signaling pathway induced by arsenic exposure was systematically reviewed and analyzed by meta-analysis. Some databases were searched including PubMed, Web of Science, China National Knowledge Infrastructure (CNKI), and WANFANG MED ONLINE. The results of NF-κB, IKK, NF-κBp65, phospho-NF-κBp65, and TLR4 expressions were analyzed by Review Manage 5.3. In the arsenic intervention group, NF-κB, phospho-NF-κBp65, and TLR4 expression levels were higher than the control group, respectively. SMD and 95%CI were 11.29 (6.34, 16.24), 4.71(1.73, 7.68), and 5.79 (-4.22, 15.80). Compared to controls, in the exposed group, IKK levels were found to be 38.11-fold higher (Z = 0.97; P = 0.33); NF-κBp65 levels were found to be 0.92-fold higher (Z = 3.33; P = 0.0009) for normal cells and tissue, while IKK levels were found to be 5.18-fold lower (Z = 5.34; P < 0.0001); NF-κBp65 levels were found to be 2.01-fold lower (Z = 3.87; P = 0.0001) for abnormal cells. With comparing of low dose, high dose of arsenic exposure was found to reduce the expression of NF-κB, but increase the expression of NF-κBp65. This review supports the alterations in related proteins on the TLR4 signaling pathway induced by arsenic exposure, which is helpful to provide theoretical basis for the mechanism of toxicity of arsenic-induced immune system damage.

Herbo-metallic ethnomedicine 'Malla Sindoor' ameliorates lung inflammation in murine model of allergic asthma by modulating cytokines status and oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Asthma is the leading inflammatory disease of the airways with inadequate therapeutic options. 'Malla Sindoor' (MS) is a metal-based ethnomedicinal formulation that has been prescribed in the ancient traditional medicinal system for treating chronic inflammations.

AIM OF THE STUDY

Here, we validated the anti-inflammatory and anti-asthmatic properties of traditional metallic medicine MS in asthmatic mice model and in LPS stimulated human monocytic THP-1 cells, by examining the relevant cellular, biochemical and molecular intermediates.

MATERIALS AND METHODS

Scanning Electron Microscope (SEM), Electron Dispersive X-ray (EDX), and X-Ray Diffraction (XRD) were performed to characterize MS particles. Allergic asthma was induced in Balb/c mice through intraperitoneal ovalbumin (OVA) injection. Experimental groups include, normal control, disease control, Dexamethasone (2 mg/kg) and three MS treated groups: 4.3 mg/kg, 13 mg/kg, and 39 mg/kg. Quantitative PCR, inflammatory cytokines and anti-oxidant enzymes, and histological analysis were performed, in the treated mice and LPS stimulated human monocytic THP-1 cells for determining the MS efficacy.

RESULTS

SEM image analysis showed the MS to be heterogenous in shape with a particle size distribution between 100 nm-1 μm. Elemental composition showed the presence of mercury (Hg), arsenic (As), and sulphur (S) along with other elements in the forms of mercury sulfide, arsenic trioxide, and their alloy crystals. OVA-challenge of the Balb/c mice resulted in the development of overt pathological features for allergic asthma including smooth muscle thickening and collagen deposition. Mice receiving MS-exhibited alleviation of allergic asthma features. BAL fluid analysis showed a decrease in the total cell count and decreases in neutrophils, monocytes, lymphocytes, and eosinophils. Further, the stimulated levels of interleukin (IL)-1β, -6, and TNF-α cytokines and antioxidant levels were also reduced upon MS-treatment. At the molecular level, MS-treatment reduced stimulated mRNA expression levels for IL-4, -5, -10, -13, -33, and IFN-γ cytokines. Histological analysis following MS-treatment of OVA-stimulated mice lungs showed a reduction in mucus accumulation in airways, decreases in peribronchial collagen deposition, bronchial smooth muscle thickening, and attenuation of inflammatory cell infiltration. In addition, under in-vitro conditions, MS-treatment attenuated the LPS induced secretion of IL-1β, -6, and TNF-α from THP-1 cells.

CONCLUSION

Collectively, the results suggest that MS acts as an effective anti-asthmatic and anti-inflammatory agent, by regulating various cellular, biochemical and molecular intermediates.

Counteracting arsenic toxicity: Curcumin to the rescue?

Arsenicosis leads to various irreversible damages in several organs and is considered to be a carcinogen. The effects of chronic arsenic poisoning are a result of an imbalance between pro- and antioxidant homeostasis, oxidative stress, as well as DNA and protein damage. Curcumin, the polyphenolic pigment extracted from the rhizome of Curcuma longa, is well-known for its pleiotropic medicinal effects. Curcumin has been shown to have ameliorative effects in arsenic-induced genotoxicity, nephrotoxicity, hepatotoxicity, angiogenesis, skin diseases, reproductive toxicity, neurotoxicity, and immunotoxicity. This review aims to summarize the scientific evidence on arsenic toxicity in various organs and the ameliorative effects of curcumin on the arsenic toxicity.

Old dog, new trick: Trivalent arsenic as an immunomodulatory drug

Trivalent arsenic (As(III)) is recently found to be an immunomodulatory agent. As(III) has therapeutic potential in several autoimmune and inflammatory diseases in vivo. In vitro, it selectively induces apoptosis of immune cells due to different sensitivity. At a non-toxic level, As(III) shows its multifaceted nature by inducing either pro- or anti-inflammatory functions of immune subsets. These effects are exerted by either As(III)-protein interactions or as a consequence of As(III)-induced homeostasis imbalance. The immunomodulatory properties also show synergistic effects of As(III) with cancer immunotherapy. In this review, we summarize the immunomodulatory effects of As(III), focusing on the effects of As(III) on immune subsets in vitro, on mouse models of immune-related diseases, and the role of As(III) in cancer immunotherapy. Updates of the mechanisms of action, the pioneer clinical trials, dosing, and adverse events of therapeutic As(III) are also provided.

Paclitaxel alleviated sepsis-induced acute lung injury by activating MUC1 and suppressing TLR-4/NF-κB pathway

Purpose

It has been reported that approximately 40% of ALI (acute lung injury) incidence resulted from sepsis. Paclitaxel, as a classic anti-cancer drug, plays an important role in the regulation of inflammation. However, we do not know whether it has a protective effect against CLP (cecal ligation and puncture)-induced septic ALI. Our study aims to illuminate the mitigative effects of paclitaxel on sepsis-induced ALI and its relevant mechanisms.

Materials and methods

The survival rates and organ injuries were used to evaluate the effects of paclitaxel on CLP mice. The levels of inflammatory cytokines were tested by ELISA. MUC1 siRNA pre-treatment was used to knockdown MUC1 expression in vitro. GO203 was used to inhibit the homodimerization of MUC1-C in vivo. The expression levels of MUC1, TLR 4 and p-NF-κB/p65 were detected by Western blot.

Results

Our results showed that paclitaxel improved the survival rates and ameliorated organ injuries especially lung injury in CLP-induced septic mice. These were accompanied by reduced inflammatory cytokines in sera and BALF (bronchoalveolar lavage fluid). We also found paclitaxel could attenuate TLR 4-NF-κB/p65 activation both in lung tissues of septic mice and LPS-stimulated lung type II epithelial cell line A549. At the upstream level, paclitaxel-upregulated expression levels of MUC1 in both in vivo and in vitro experiments. The inhibitory effects of paclitaxel on TLR 4-NF-κB/p65 activation were reversed in lung tissues of septic mice pre-treated with MUC1 inhibitor and in MUC1-knockdown A549 cells. Protection of paclitaxel on sepsis-induced ALI and decrease of inflammatory cytokines were also abolished by inhibition of MUC1.

Conclusion

Collectively, these results indicated paclitaxel could significantly alleviate acute lung injury in CLP-induced septic mice and LPS-stimulated lung type II epithelial cell line A549 by activating MUC1 and suppressing TLR-4/NF-κB pathway.

Stressed: The Unfolded Protein Response in T Cell Development, Activation, and Function

The unfolded protein response (UPR) is a highly conserved pathway that allows cells to respond to stress in the endoplasmic reticulum caused by an accumulation of misfolded and unfolded protein. This is of great importance to secretory cells because, in order for proteins to traffic from the endoplasmic reticulum (ER), they need to be folded appropriately. While a wealth of literature has implicated UPR in immune responses, less attention has been given to the role of UPR in T cell development and function. This review discusses the importance of UPR in T cell development, homeostasis, activation, and effector functions. We also speculate about how UPR may be manipulated in T cells to ameliorate pathologies.

Double-Sided Personality: Effects of Arsenic Trioxide on Inflammation

In 1992, arsenic trioxide (As₂O₃, ATO) was demonstrated to be an effective therapeutic agent against acute promyelocytic leukemia (APL), rekindling attention to ATO applications in U.S. Food and Drug Administration clinical trials for the treatment of cancers, such as leukemia, lymphomas, and solid tumors. ATO is a potent chemotherapeutic drug that can also be used to treat other diseases, such as autoimmune diseases, because it affects multiple pathways including apoptosis induction, differentiation stimulation, and proliferation inhibition. As inflammation is a critical component of disease progression, ATO is a feasible treatment option based on its ability to protect against inflammation. However, ATO is also a well-known carcinogen because of its pro-inflammatory effect. This review will focus on the double-sided effects of ATO on inflammation as well as the relevant mechanisms underlying these effects, aiming to provide a rational understanding of how ATO effects the immune system. We especially aim to provide a comprehensive overview of our current knowledge of how ATO influences inflammation.

Application of the adverse outcome pathway (AOP) approach to inform mode of action (MOA): A case study with inorganic arsenic

The aim of this study was to establish a process for deriving a chemical-specific mode of action (MOA) from chemical-agnostic adverse outcome pathway (AOPs), using inorganic arsenic (iAs) as a case study. The AOP developed for this case study are related to disruption of cellular signaling by chemicals that strongly bind to vicinal dithiols in cellular proteins, leading to disruption of inflammatory and oxidative stress signaling along with inhibition of the DNA damage responses. The proposed MOA for iAs incorporates this AOP, overlaid on a background of increasing oxidative stress and/or co-exposure to mutagenic chemicals or radiation. The most challenging aspect of developing a MOA from AOP is the incorporation of metabolism and dose-response, neither of which may be considered in the development of an AOP. The cellular responses to relatively low concentrations (below 100 parts per billion) of iAs in drinking water appear to be secondary to binding of trivalent arsenite and its trivalent metabolite, monomethyl arsenous acid to key cellular vicinal dithiols in target tissues, resulting in a co-carcinogenic MOA. The proposed AOP may also be applied to non-cancer endpoints, enabling an integrated approach to conducting a risk assessment for iAs.

The Cell Research Trends of Asthma: A Stem Frequency Analysis of the Literature

Objective

This study summarized asthma literature indexed in the Medical Literature Analysis and Retrieval System Online (MEDLINE) and explored the history and present trends of asthma cell research by stem frequency ranking to forecast the prospect of future work.

Methods

Literature was obtained from MEDLINE for the past 30 years and divided into three groups by decade as the retrieval time. The frequency of stemmed words in each group was calculated using Python with Apache Spark and the Natural Language Tool Kit for ranking. The unique stems or shared stems of 3 decades were summarized.

Results

A total of 1331, 4393, and 7215 records were retrieved from 3 decades chronologically, and the stem ranking of the top 50 were listed by frequency. The number of stems shared with 3 decades was 26 and with the first and last 2 decades was 5 and 13.

Conclusions

The number of cell research studies of asthma has increased rapidly, and scholars have paid more attentions on experimental research, especially on mechanistic research. Eosinophils, mast cells, and T cells are the hot spots of immunocyte research, while epithelia and smooth muscle cells are the hot spots of structural cell research. The research trend is closely linked with the development of experimental technology, including animal models. Early studies featured basic research, but immunity research has dominated in recent decades. The distinct definition of asthma phenotypes associated with genetic characteristics, immunity research, and the introduction of new cells will be the hot spots in future work.

MicroRNA‑16 inhibits interleukin‑13‑induced inflammatory cytokine secretion and mucus production in nasal epithelial cells by suppressing the IκB kinase β/nuclear factor‑κB pathway

Chronic inflammation of the nasal mucosal tissue plays important roles in the pathogenesis of allergic rhinitis (AR). Aberrantly expressed microRNAs (miRNAs) have been found to have strong associations with inflammatory reactions in allergic diseases; however, its functional significance and molecular mechanism underlying in AR remains unclear. The aim of the present study was to investigate the biological functions of miRNA and reveal its underlying molecular mechanisms in AR. miRNA microarray was performed to analyze miRNAs expression levels in 3 paired nasal mucosal samples from patients with AR and a control group. Subsequently, human nasal epithelial cells (JME/CF15) were used as an in vitro model to further explore the functions of miRNAs. Microarray data revealed that miR‑16 was one of the miRNAs being most significantly downregulated. Interleukin (IL)‑13 stimulation gradually decreased the levels of miR‑16 in JME/CF15 cells. Moreover, upregulation of miR‑16 inhibited inflammatory cytokines, including granulocyte‑macrophage colony‑stimulating factor (GM‑CSF), eotaxin, IL‑1β, IL‑6 and IL‑10 in IL‑13‑treated JME/CF15 cells. Furthermore, overexpression of miR‑16 significantly decreased the mRNA and protein expression levels of mucin 5AC (MUC5AC). IκB kinase β (IKKβ) was identified as a direct target of miR‑16 and its expression was negatively regulated by miR‑16 at mRNA and protein levels. Notably, forced expression of miR‑16 blocked NF‑κB signaling by decreasing the expression of nuclear p‑p65 and p‑IκB‑α, as well as increasing the expression of IκB‑α in IL‑13‑treated nasal epithelial cells. Moreover, enhanced IKKβ reactivated the NF‑κB pathway that was blocked by miR‑16 mimics and then effectively suppressed the miR‑16‑mediated inhibitory effects on inflammatory response. These findings suggested that miR‑16 suppressed the inflammatory response by inhibiting the activation of IKKβ/NF‑κB signaling pathways.

IL-17A Monoclonal Antibody Partly Reverses the Glucocorticoids Insensitivity in Mice Exposed to Ozonec

Exposure to ozone has been associated with airway inflammation and glucocorticoid insensitivity. This study aimed to observe the capacity of anti-murine interleukin-17A monoclonal antibody (IL-17mAb) to reverse ozone-induced glucocorticoid insensitivity and to detect its effects with glucocorticoids in protecting against airway inflammation. After C57/BL6 mice were exposed to ozone (2.5 ppm; 3 h) for 12 times over 6 weeks, PBS, IL-17mAb (50 ug/ml), dexamethasone (2 mg/kg), and combination administration of IL-17mAb (50 ug/ml) and dexamethasone (2 mg/kg) were intraperitoneally injected into mice at a dose of 0.1 ml, respectively, for 10 times over 5 weeks. At sacrifice, lung histology, airway inflammatory cells, levels of related cytokines in bronchoalveolar lavage fluid (BALF), and serum were analyzed, airway inflammatory cell infiltration density and mean linear intercept (Lm) were measured, the expression of IL-17A mRNA, glucocorticoid receptors (GR), NF-κB, and p38 mitogen-activated protein kinase (MAPK) phosphorylation were determined. We found that combination administration markedly reduced ozone-induced total inflammatory cells, especially neutrophils; inhibited levels of cytokines, including IL-8, IL-17A, and TNF-α in BALF; and suppressed airway inflammatory cell infiltration density and Lm. Additionally, combination administration significantly elevated levels of IFN-γ in BALF, decreased the dexamethasone-induced increase of IL-17A mRNA, and increased the expression of GR and decrement of NF-κB and p38MAPK phosphorylation, which are also related to glucocorticoids insensitivity. Collectively, combination administration shows profound efficacy in inhibiting certain cytokines, and IL-17 mAb partly improved the glucocorticoids insensitivity via modulating the enhanced production rate and improving expression of IL-17A induced by glucocorticoids administration and p38MAPK, NF-κB signaling pathway.

Unique pulmonary immunotoxicological effects of urban PM are not recapitulated solely by carbon black, diesel exhaust or coal fly ash

BACKGROUND

Exposure to particulate matter (PM) is increasing worldwide as a result of increased human activity, the rapid industrialization of developing countries, and effects of climate change. Adverse effects of PM on human health are well documented, and because PM exposure occurs mostly through the airways, PM has especially deleterious impact on the lungs.

OBJECTIVE

We investigated whether surrogate PM particles like carbon black (CB), diesel exhaust particle (DEP), coal fly ash (CFA) can recapitulate the allergic airway inflammatory response induced by urban particulate matter.

METHODS

We compared the pro-inflammatory potential of urban PM collected from New York (NYC) and Baltimore (Balt) with CB, DEP and CFA surrogate PM particles. Eight to ten weeks old BALB/cJ mice were exposed through the airways to particulate material, and markers of airway inflammation were determined. Specifically, we assessed cellular influx, mucus production, lung function, cytokine levels as well as immune cell profiling of the lungs.

RESULTS

Herein, we demonstrate that exposure to equivalent mass of stand-alone surrogate PM particles like CB, DEP and CFA, fails to induce significant airway inflammatory response seen after similar exposure to urban PMs. Specifically, we observe that PM collected from New York (NYC) and Baltimore city (Balt) triggers a mixed Th2/Th17 response accompanied by eosinophilic and neutrophilic influx, mucus production and airway hyperresponsiveness (AHR). Although the immune profile of NYC and Baltimore PMs are similar, they demonstrate considerable differences in their potency. Baltimore PM induced more robust airway inflammation, AHR, and Th2 cytokine production, possibly due to the greater metal content in Baltimore PM.

CONCLUSIONS

Urban particulate matter with its unique physiochemical properties and heterogeneous composition elicits a mixed Th2/Th17 allergic airway response that is not seen after similar exposures to surrogate PM particles.

Cortisol inhibits NF-κB and MAPK pathways in LPS activated bovine endometrial epithelial cells

The bovine uterus is subject to infection after calving, which may lead to endometritis. Elevated cortisol levels have been observed in postpartum cattle. However, the role of cortisol in the inflammatory response of the uterus has not been reported. The aim of this study was to investigate the anti-inflammatory effects of cortisol on lipopolysaccharide (LPS)-induced primary bovine endometrial epithelial cells (BEECs). BEECs were treated with various concentrations of cortisol (5, 15 and 30 ng/mL) in the presence of LPS. The mRNA expression of TLR4 and proinflammatory cytokines was measured with qPCR. The activation of NF-κB and MAPK signalling pathways was detected with Western blotting and immunofluorescence. Cortisol induced the down-regulation of the mRNA expression of toll-like receptor 4 (TLR4) and proinflammatory cytokines, including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS). Cortisol inhibited the activity of nuclear factor-κB (NF-κB) via blocking the phosphorylation and degradation of IκB. Cortisol suppressed the phosphorylation of mitogen-activated protein kinase (MAPK), including extracellular signal-regulated kinase (ERK1/2), p38MAPK and c-Jun N-terminal kinase/stress-activated protein kinase (JNK). These results demonstrated that cortisol may exert its anti-inflammatory actions by regulating NF-κB activation and MAPK phosphorylation.

Paclitaxel alleviated liver injury of septic mice by alleviating inflammatory response via microRNA-27a/TAB3/NF-κB signaling pathway

Excessive inflammatory response and apoptosis play an important role in the sepsis-induced liver injury. Paclitaxel, a diterpene alkaloid of Taxus brevifolia, is widely used as an anti-tumor drug and shows protective effects on acute lung and kidney injury. However, whether it has a protective effect against sepsis-induced liver injury has not been reported. The objective of this study was to investigate the protective effects of paclitaxel in septic liver injury in mice and associated molecular mechanisms. Our results showed that paclitaxel treatment improved LPS-induced liver injury, as evidenced by the reduced aminotransferase activity, histological scores and apoptosis in the liver tissues. This was accompanied by the alleviating of inflammation and oxidative stress, such as decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and malondialdehyde (MDA) and increased levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) in serum and liver tissues. Subsequent microarray and qRT-PCR analysis further showed that miR-27a was significantly decreased in mice with sepsis, which was recovered by paclitaxel pretreatment. Antagomir-miR-27a suppressed the therapeutic effects of paclitaxel in mice liver injury model via promoting inflammatory response. Of note, TAB3, which participated in the activation of the NF-κB signaling pathway, was identified as a direct target of miR-27 by luciferase reporter gene assays. Then, we revealed a reverse relationship between miR-27a expression levels and TAB3 mRNA levels in liver tissues from septic mice. Furthermore, paclitaxel treatment significantly decreased the expression of NF-κB p65, but increased inhibitor of nuclear factor-κB-α (IκBα) protein levels in septic mice, suggesting the inactivation of NF-κB signaling pathway. Notably, the inhibitory effects of paclitaxel on NF-κB signaling pathway were reversed by antagomir-miR-27a. Our data indicated that paclitaxel significantly attenuated septic induced liver injury through reducing inflammatory response via miR-27a/TAB3/NF-κB signaling pathway.

Activating transcription factor 4 underlies the pathogenesis of arsenic trioxide-mediated impairment of macrophage innate immune functions

Chronic arsenic exposure to humans is considered immunosuppressive with augmented susceptibility to several infectious diseases. The exact molecular mechanisms, however, remain unknown. Earlier, we showed the involvement of unfolded protein response (UPR) signaling in arsenic-mediated impairment of macrophage functions. Here, we show that activating transcription factor 4 (ATF4), a UPR transcription factor, regulates arsenic trioxide (ATO)-mediated dysregulation of macrophage functions. In ATO-treated ATF4(+/+) wild-type mice, a significant down-regulation of CD11b expression was associated with the reduced phagocytic functions of peritoneal and lung macrophages. This severe immuno-toxicity phenotype was not observed in ATO-treated ATF4(+/-) heterozygous mice. To confirm these observations, we demonstrated in Raw 264.7 cells that ATF4 knock-down rescues ATO-mediated impairment of macrophage functions including cytokine production, bacterial engulfment and clearance of engulfed bacteria. Sustained activation of ATF4 by ATO in macrophages induces apoptosis, while diminution of ATF4 expression protects against ATO-induced apoptotic cell death. Raw 264.7 cells treated with ATO also manifest dysregulated Ca(++) homeostasis. ATO induces Ca(++)-dependent calpain-1 and caspase-12 expression which together regulated macrophage apoptosis. Additionally, apoptosis was also induced by mitochondria-regulated pathway. Restoring ATO-impaired Ca(++) homeostasis in ER/mitochondria by treatments with the inhibitors of inositol 1,4,5-trisphosphate receptor (IP3R) and voltage-dependent anion channel (VDAC) attenuate innate immune functions of macrophages. These studies identify a novel role for ATF4 in underlying pathogenesis of macrophage dysregulation and immuno-toxicity of arsenic.

Association between polymorphisms in arsenic metabolism genes and urinary arsenic methylation profiles in girls and boys chronically exposed to arsenic

Disease manifestations or susceptibilities often differ among individuals exposed to the same concentrations of arsenic (As). These differences have been associated with several factors including As metabolism, sex, age, genetic variants, nutritional status, smoking, and others. This study evaluated the associations between four As metabolism-related gene polymorphisms/null genotypes with urinary As methylation profiles in girls and boys chronically exposed to As. In a total of 332 children aged 6-12 years, the frequency of AS3MT, GSTO1, GSTT1, and GSTM1 polymorphisms/null genotypes and As urinary metabolites were measured. The results revealed that total As and monomethyl metabolites of As (MMA) levels were higher in boys than in girls. No differences in the frequency of the evaluated polymorphisms were found between girls and boys. In AS3MT-Met287Thr carriers, %MMA levels were higher and second methylation levels (defined as dimethylarsinic acid divided by MMA) were lower. In children with the GSTM1 null genotype, second methylation levels were higher. In boys, a positive association between the AS3MT-Met287Thr polymorphism with %MMA and between the GSTO1-Glu155del and As(v) was found; whereas, a negative relationship was identified between AS3MT-Met287Thr and second methylation profiles. In girls, a positive association was found between the GSTO1-Ala140Asp polymorphism with second methylation levels. In conclusion, our data indicate that gender, high As exposure levels, and polymorphisms in the evaluated genes negatively influenced As metabolism. Environ. Mol. Mutagen. 57:516-525, 2016. © 2016 Wiley Periodicals, Inc.

Modification of association between prior lung disease and lung cancer by inhaled arsenic: A prospective occupational-based cohort study in Yunnan, China

Arsenic and prior lung diseases have been shown to increase lung cancer risk; however, little is known about their joint effects. The aim of our study was to analyze the joint effects of inhaled arsenic and prior lung diseases on lung cancer risk within a occupational cohort. The interactions of prior lung diseases and inhaled arsenic were analyzed based on multiplicative and additive scales in the Cox proportional hazards model. Compared with low arsenic exposure and no history of asthma, the hazard ratios (HRs) of high arsenic exposure with asthma, high arsenic exposure without asthma and low arsenic exposure with asthma were 2.61 (95% CI: 1.71-4.00), 2.60 (95% CI: 1.93-3.51) and 2.49 (95% CI: 1.53-4.06), respectively. Based on the multiplicative scale in the Cox proportional hazards model, the HR of the interaction of asthma and arsenic on lung cancer risk was 0.45 (95% CI: 0.25-0.80). Based on the additive scale, the relative excess risk due to interaction between asthma and arsenic was -1.41 (95% CI: -2.81 to -0.02). Our study provides strong evidence that arsenic exposure is associated with lung cancer risk. A significant negative interaction between asthma and arsenic on lung cancer risk is observed.

Arsenic inhibits mast cell degranulation via suppression of early tyrosine phosphorylation events

Exposure to arsenic is a global health concern. We previously documented an inhibitory effect of inorganic Arsenite on IgE-mediated degranulation of RBL-2H3 mast cells (Hutchinson et al., 2011; J. Appl. Toxicol. 31: 231-241). Mast cells are tissue-resident cells that are positioned at the host-environment interface, thereby serving vital roles in many physiological processes and disease states, in addition to their well-known roles in allergy and asthma. Upon activation, mast cells secrete several mediators from cytoplasmic granules, in degranulation. The present study is an investigation of Arsenite's molecular target(s) in the degranulation pathway. Here, we report that arsenic does not affect degranulation stimulated by either the Ca(2) (+) ionophore A23187 or thapsigargin, which both bypass early signaling events. Arsenic also does not alter degranulation initiated by another non-IgE-mediated mast cell stimulant, the G-protein activator compound 48/80. However, arsenic inhibits Ca(2) (+) influx into antigen-activated mast cells. These results indicate that the target of arsenic in the degranulation pathway is upstream of the Ca(2) (+) influx. Phospho-Syk and phospho-p85 phosphoinositide 3-kinase enzyme-linked immunosorbent assays data show that arsenic inhibits early phosphorylation events. Taken together, this evidence indicates that the mechanism underlying arsenic inhibition of mast cell degranulation occurs at the early tyrosine phosphorylation steps in the degranulation pathway. Copyright © 2016 John Wiley & Sons, Ltd.

Divergent Effects of Arsenic on NF-κB Signaling in Different Cells or Tissues: A Systematic Review and Meta-Analysis

Arsenic is ubiquitously present in human lives, including in the environment and organisms, and has divergent effects between different cells and tissues and between different exposure times and doses. These observed effects have been attributed to the nuclear transcription factor kappa B(NF-κB) signaling pathway. Herein, a meta-analysis was performed by independently searching databases including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze effects of arsenic exposure on NF-κB signaling. Compared to controls, in the exposed group, p-IκB levels were found to be 8.13-fold higher (95% CI, 2.40-13.85; Z = 2.78; p = 0.005), IκB levels were 16.19-fold lower (95% CI, -27.44--4.94; Z = 2.78; p = 0.005), and NF-κBp65 levels were 0.77-fold higher (95% CI, 0.13-1.42; Z = 2.34; p = 0.02) for normal cells and tissue, while NF-κBp65 levels were 4.90-fold lower (95% CI, -8.49-1.31; Z = 2.62; p = 0.009), NF-κB activity was 2.45-fold lower (95% CI, -3.66-1.25; Z = 4.00; p < 0.0001), and DNA-binding activity of NF-κB was 9.75-fold lower (95% CI, -18.66-4.54; Z = 2.15; p = 0.03) for abnormal cells and tissue. Short exposure to high arsenic doses activated the NF-κB signaling pathway, while long exposure to low arsenic doses suppressed NF-κB signaling pathway activation. These findings may provide a theoretical basis for injurious and therapeutic mechanisms of divergent effects of arsenic.

Long-term azithromycin ameliorates not only airway inflammation but also remodeling in a murine model of chronic asthma

OBJECTIVES

We investigated the effect of long-term treatment with azithromycin on the pathogenesis of chronic asthma with airway remodeling.

METHODS

Six-week-old-BALB/c mice were sensitized with ovalbumin (OVA) combined with lipopolysaccharide (LPS) for 1 month, then challenged with OVA for 3 months. Azithromycin at 75 mg/kg was administered via oral gavage five times a week during the challenge period. Inflammatory cells, T helper 2 cytokines in bronchoalveolar lavage fluid (BAL) fluid, and airway hyperresponsiveness (AHR) were measured. Parameters related to airway remodeling were evaluated. The levels of neutrophil elastase, Interleukin (IL)-8, and BRP-39 (human homologue YKL-40) were assessed. The expression of MAPK and NF-κB signaling were investigated.

RESULTS

Long-term treatment with azithromycin improved AHR and airway inflammation compared with the OVA and the OVA/LPS groups. The concentrations of IL-5 and IL-13 in the OVA/LPS group decreased significantly after azithromycin administration. The levels of neutrophil elastase and IL-8, as surrogate markers of neutrophil activation, were reduced in the azithromycin group compared with the OVA/LPS group. Goblet cell hyperplasia and the smooth muscle thickening of airway remodeling were attenuated after azithromycin treatment. The expression of MAPK/NF-kappaB signal and the level of BRP-39 in the lung decreased remarkably in the OVA/LPS with azithromycin-treated group.

CONCLUSIONS

This study suggests that in a murine model of chronic asthma, long-term azithromycin treatment ameliorates not only airway inflammation but also airway remodeling by influencing on neutrophilc-related mediators, BRP-39 and MAPK/NF-κB signal pathways. Macrolide therapy might be an effective adjuvant therapy in a chronic, severe asthma with remodeling airway.

Evaluation of Arsenic Trioxide Potential for Lung Cancer Treatment: Assessment of Apoptotic Mechanisms and Oxidative Damage

Background

Lung cancer is one of the most lethal and common cancers in the world, causing up to 3 million deaths annually. The chemotherapeutic drugs that have been used in treating lung cancer include cisplatin-pemetrexed, cisplastin-gencitabinoe, carboplatin-paclitaxel and crizotinib. Arsenic trioxide (ATO) has been used in the treatment of acute promyelocytic leukemia. However, its effects on lung cancer are not known. We hypothesize that ATO may also have a bioactivity against lung cancer, and its mechanisms of action may involve apoptosis, DNA damage and changes in stress-related proteins in lung cancer cells.

Methods

To test the above stated hypothesis, lung carcinoma (A549) cells were used as the test model. The effects of ATO were examined by performing 6-diamidine-2 phenylindole (DAPI) nuclear staining for morphological characterization of apoptosis, flow cytometry analysis for early apoptosis, and western blot analysis for stress-related proteins (Hsp70 and cfos) and apoptotic protein expressions. Also, the single cell gel electrophoresis (Comet) assay was used to evaluate the genotoxic effect.

Results

ATO-induced apoptosis was evidenced by chromatin condensation and formation of apoptotic bodies as revealed by DAPI nuclear staining. Cell shrinkage and membrane blebbing were observed at 4 and 6 µg/ml of ATO. Data from the western blot analysis revealed a significant dose-dependent increase (p < 0.05) in the Hsp 70, caspase 3 and p53 protein expression, and a significant (p < 0.05) decrease in the cfos, and bcl-2 protein expression at 4 and 6 µg/ml of ATO. There was a slight decrease in cytochrome c protein expression at 4 and 6 µg/ ml of ATO. Comet assay data revealed significant dose-dependent increases in the percentages of DNA damage, Comet tail lengths, and Comet tail moment.

Conclusion

Taken together our results indicate that ATO is cytotoxic to lung cancer cells and its bioactivity is associated with oxidative damage, changes in cellular morphology, and apoptosis.

Impact of ozone exposure on the response to glucocorticoid in a mouse model of asthma: involvements of p38 MAPK and MKP-1

Background

Molecular mechanisms involved in the oxidative stress induced glucocorticoids insensitivity remain elusive. The mitogen-activated protein kinase phosphatase (MKP) 1 mediates a part of glucocorticoids action and can be modified by exogenous oxidants. Whether oxidant ozone (O₃) can affect the function of MKP-1 and hence blunt the response to corticotherapy is not clear.

Methods

Here we employed a murine model of asthma established with ovalbumin (OVA) sensitization and challenge to evaluate the influence of O₃ on the inhibitory effect of dexamethasone on AHR and airway inflammation, and by administration of SB239063, a selective p38 MAPK inhibitor, to explore the underlying involvements of the activation of p38 MAPK and the expression of MKP-1.

Results

Ozone exposure not only aggravated the pulmonary inflammation and AHR, but also decreased the inhibitory effects of dexamethasone, accompanied by the elevated oxidative stress, airway neutrophilia, enhanced phosphorylation of p38 MAPK, and upregulated expression of IL-17. Administration of SB239063 caused significant inhibition of the p38 MAPK phosphorylation, alleviation of the airway neutrophilia, and decrement of the ozone-induced IL-17 expression, and partly restored the ozone-impaired effects of dexamethasone. Ozone exposure not only decreased the protein expression of MKP-1, but also diminished the dexamethasone-mediated induction process of MKP-1 mRNA and protein expression.

Conclusions

The glucocorticoids insensitivity elicited by ozone exposure on current asthma model may involve the enhanced phosphorylation of p38 MAPK and disturbed expression of MKP-1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0126-x) contains supplementary material, which is available to authorized users.

Unfolded protein response (UPR) signaling regulates arsenic trioxide-mediated macrophage innate immune function disruption

Arsenic exposure is known to disrupt innate immune functions in humans and in experimental animals. In this study, we provide a mechanism by which arsenic trioxide (ATO) disrupts macrophage functions. ATO treatment of murine macrophage cells diminished internalization of FITC-labeled latex beads, impaired clearance of phagocytosed fluorescent bacteria and reduced secretion of pro-inflammatory cytokines. These impairments in macrophage functions are associated with ATO-induced unfolded protein response (UPR) signaling pathway characterized by the enhancement in proteins such as GRP78, p-PERK, p-eIF2α, ATF4 and CHOP. The expression of these proteins is altered both at transcriptional and translational levels. Pretreatment with chemical chaperon, 4-phenylbutyric acid (PBA) attenuated the ATO-induced activation in UPR signaling and afforded protection against ATO-induced disruption of macrophage functions. This treatment also reduced ATO-mediated reactive oxygen species (ROS) generation. Interestingly, treatment with antioxidant N-acetylcysteine (NAC) prior to ATO exposure, not only reduced ROS production and UPR signaling but also improved macrophage functions. These data demonstrate that UPR signaling and ROS generation are interdependent and are involved in the arsenic-induced pathobiology of macrophage. These data also provide a novel strategy to block the ATO-dependent impairment in innate immune responses.

Geniposide inhibits airway inflammation and hyperresponsiveness in a mouse model of asthma

Our group recently reported the strong anti-inflammatory effects of geniposide (Gen), a bioactive iridoid glucoside derived from gardenia jasminoides, in a mouse acute lung injury model. Herein, we hypothesized that Gen might also have potential therapeutic benefits in treatment of asthma, which was tested in a mouse model of ovalbumin (Ova)-induced allergic airway inflammation. Ova-sensitized and -challenged BALB/c mice, as compared with control animals, displayed airway hyperresponsiveness (AHR), bronchoalveolar lavage eosinophilia, mucus hypersecretion, and increased T help 2 (Th2)-associated cytokine and chemokine amounts, as well as serum Ova-specific immunoglobulin E (IgE) level. Being compared with the Ova-induced hallmarks of asthma, intraperitoneal Gen treatment prevented eosinophilic pulmonary infiltration, attenuated the increases in interleukin (IL)-4, IL-5, and IL-13, and reduced eotaxin and vascular cell adhesion molecule 1 (VCAM-1) expression. Also, Gen significantly ameliorated the Ova-driven airway hyperresponsiveness, mucus hypersecretion, and allergen-specific IgE level, which are the cardinal pathophysiological symptoms in allergic airway diseases. In addition, the efficacy of Gen was comparable to that of dexamethasone (Dex), a currently available anti-asthmatic drug. Collectively, our findings reveal that the development of immunoregulatory strategies based on Gen may be considered as an effective adjuvant therapy for allergic asthma.

Effect of therapeutic arsenic exposure on pulmonary function

AIM

Arsenic-contaminated drinking water has been associated with respiratory diseases and lung function impairment. Oral arsenic trioxide (ATO) is a standard treatment for acute promyelocytic leukaemia. This study aimed to explore the effect of therapeutic exposure to arsenic on lung function.

PATIENTS AND METHOD

This was a case-control cross-sectional study on patients with haematological malignancies with or without exposure to ATO. Full lung function tests and serum Clara cell protein 16 (CC16) were measured.

RESULTS

There were 57 cases (arsenic exposed) and 57 matched controls (arsenic non-exposed) recruited. Among cases, the median duration of ATO exposure was 519 (194-1259) days. The mean FEV(1)/FVC ratio, FEV(1) (% predicted), and RV/TLC (%), as well as % subjects with FEV(1)/FVC below lower limits of normal (LLN), were similar in the two groups with or without arsenic exposure. However the mean TLC (% predicted) and DLCO/VA were significantly higher in arsenic-exposed versus non-exposed group (p = 0.01 and p = 0.008 respectively). There were mildly reduced FEV(1)/FVC ratio and FEF(25-75) (% predicted), largely within normal limits, among high level arsenic exposure compared with non-exposure (p = 0.01 and p = 0.05 respectively). Serum CC16 was comparable among both arsenic exposed and non-exposed groups.

CONCLUSION

Therapeutic use of oral ATO for a median of around 1.5 years was not associated with clinically significant lung function impairment.

Arsenic trioxide alleviates airway hyperresponsiveness and promotes apoptosis of CD4+ T lymphocytes: evidence for involvement of the ER stress-CHOP pathway

BACKGROUND

Asthma is a chronic inflammatory disorder of the airway. Arsenic trioxide (ATO) is an ancient Chinese medicine, which is used to treat psoriasis, asthma, and acute promyelocytic leukemia.

AIM

We wanted to research the effect of arsenic trioxide on asthma.

METHODS

Using a murine model of asthma, the airway hyperresponsiveness was conducted by the Buxco pulmonary function apparatus. Total cell counts of BALF were counted with a counting chamber. Histopathological analysis of lung tissues was conducted by hematoxylin-eosin or periodic acid-schiff stain. CD4+T cells were purified from the spleen by positive selection, using immunomagnetic beads. Apoptosis measurements were done with Annexin-V/PI staining. Western blot analysis and real time-PCR were performed to assess the expression of C/EBP-homologous protein (CHOP) and glucose-regulated protein 78 (GRP78), respectively. RNA interference was conducted to inhibit the expression of CHOP.

RESULTS

We found that arsenic trioxide treatment alleviated airway hyperresponsiveness and reduced inflammation of the lung in asthmatic mice. Furthermore, arsenic trioxide treatment promoted apoptosis of CD4+T cells in vivo and in vitro. When CD4+T cells were cultured with arsenic trioxide for 5 h at a concentration of 5 μM, the expression of GRP78 and CHOP was increased. Treatment of CD4+T cells with CHOP siRNA, provided partial resistance to arsenic trioxide-induced apoptosis of CD4+T cells

CONCLUSIONS

These data demonstrated that arsenic trioxide can reduce the severity of asthma attacks and induce the apoptosis of CD4+ T cell which the ER stress-CHOP pathway involved.

Effects of arsenic trioxide (As(2)O(3)) on airway remodeling in a murine model of bronchial asthma

We investigated the effects of arsenic trioxide (As(2)O(3)) as a possible approach for preventing airway remodeling in a murine model of bronchial asthma induced by ovalbumin (OVA) challenge. Forty Balb/c mice were randomly assigned to 1 of 4 groups (10 mice/group) as follows: controls (challenged with sterile saline inhalation only); OVA-challenged, no treatment; OVA-challenged, treated with dexamethasone; and OVA-challenged, treated with As(2)O(3). All mice were sensitized by intraperitoneal injection with 10% OVA at 2 weeks prior to saline or OVA inhalation challenge. Challenges were for 8 weeks. After OVA challenge, typical asthma-like morphology changes in the bronchi and lung tissues were observed by hematoxylin-eosin staining and pulmonary function indices were reduced compared with controls. Changes in pulmonary indices and lung tissues were similar in the dexamethasone and As(2)O(3) groups and were in between those of the untreated and control groups. Compared with the untreated group, transforming growth factor β1, vascular endothelial growth factor, and matrix metalloproteinase-9 protein levels and mRNA expression were decreased in lung tissues of the dexamethasone and As(2)O(3) groups. Our results suggest that steroids and As(2)O(3) can inhibit airway remodeling in chronic asthma by mechanisms related to inhibiting the expression of the 3 aforementioned mediators.

Mucin 5 Subtype AC Expression and Upregulation in the Nasal Mucosa of Allergic Rhinitis Rats

Objective

To elucidate the functions of nuclear factor kappa B (NF-κB) in mucin hypersecretion in allergic rhinitis (AR), we examined the in vivo effects of an NF-κB inhibitor, ammonium pyrrolidine dithiocarbamate (PDTC), on mucin 5 subtype AC ( MUC5AC) expression in the nasal mucosa of ovalbumin-sensitized rats.

Study Design

Randomized animal study.

Setting

Academic medical center.

Subjects and Methods

Sprague Dawley rats were randomized into a control group (group A), an AR model group (group B), and an AR model treated with an NF-κB inhibitor (group C). Rats in groups B and C were sensitized systemically and locally by ovalbumin injection and inhalation, whereas group A was treated with normal saline in place of ovalbumin. Pyrrolidine dithiocarbamate (100 mg/kg/d) was given to group C by intraperitoneal injection for 5 days. NF-κBp65, MUC5AC, tumor necrosis factor (TNF)–α, and interleukin (IL)–6 were detected by immunohistochemistry, Western blotting, enzyme-linked immunosorbent assay, or real-time polymerase chain reaction.

Results

NF-κB was activated in group B, and significant NF-κBp65 protein was expressed in the nucleus of cells from the nasal mucosa, resulting in upregulated transcription from TNF-α and IL-6 genes, as well as increased contents of TNF-α and IL-6 in the nasal lavage fluids. Pyrrolidine dithiocarbamate inhibited nuclear localization of NF-κBp65 and subsequent downregulation of the transcription and secretion of TNF-α and IL-6. MUC5AC was upregulated in group B but reduced in a time-dependent manner after inhibition of NF-κB activation.

Conclusion

NF-κB activation might induce MUC5AC hypersecretion in AR rats by inflammatory cytokines TNF-α and IL-6.

Thymic stromal lymphopoietin: a promising therapeutic target for allergic diseases

Thymic stromal lymphopoietin (TSLP), an interleukin 7-like cytokine, can trigger dendritic cell (DC)-mediated T-helper type 2 (Th2) inflammatory responses. Recent evidence demonstrates that cytokines TSLP and OX40 (CD134)/OX40 ligand seem to be important players in the maintenance of Th2 memory pool in the pathogenesis of asthma. Accumulating data reveal that the pathogenic T cells involved in asthma are likely to be inflammatory Th2 cells. TSLP is involved in the development of asthma through crosstalk with nuclear factor NF-ĸB. Progression of skin fibrosis in atopic dermatitis occurs via TSLP/TSLP receptor. TSLP-mediated dermal inflammation aggravates experimental allergic asthma. Also, TSLP polymorphisms are associated with susceptibility to asthma, atopic dermatitis, and eczema herpeticum. These findings suggest a master switch of TSLP in the initiation of allergic and adaptive inflammation through innate pathways at the epithelial cell-DC interface. The TSLP pathway is therefore a promising target for immunotherapy of allergic diseases.

Short-term roxithromycin treatment attenuates airway inflammation via MAPK/NF-κB activation in a mouse model of allergic asthma

OBJECTIVE

We investigated whether roxithromycin reduces ovalbumin-specific allergic asthma symptoms in mice, and we further investigated the inhibitory mechanism of roxithromycin in ovalbumin-specific allergic asthma.

METHODS

Mice were divided into five groups (n = 10 for each): control group, roxithromycin-treated groups (5, 20 and 40 mg/kg) and ovalbumin-challenged group. We measured the recruitment of inflammatory cells into the bronchoalveolar lavage fluid (BALF) or the lung tissues by Kwik-Diff and hematoxylin and eosin (H&E) staining, goblet cell hyperplasia by alcian blue-periodic acid-Schiff (AB-PAS) staining, airway hyperresponsiveness (AHR) by whole-body plethysmograph chamber, cytokine and immunoglobulin E (IgE) levels by ELISA, and the activation of mitogen-activated protein (MAP) kinases and nuclear factor-kappa B (NF-κB) in the lung tissues by Western blotting.

RESULTS

Treatment with roxithromycin resulted in fewer inflammatory cells in the BALF and peribronchial areas, and decreased AHR, goblet cell hyperplasia, IgE levels and inflammatory cytokines, as well as MAP kinases and NF-κB activation, which are increased in lung tissues of mice with ovalbumin-induced allergic asthma.

CONCLUSIONS

Our data suggest that oral administration of roxithromycin suppresses ovalbumin-induced airway inflammation and AHR by regulating the inflammatory cytokines via MAP kinases/NF-κB pathway in inflammatory cells. Based on these results, we suggest that roxithromycin may be used as a therapeutic agent for allergy-induced asthma.

Effects of (±)-praeruptorin A on airway inflammation, airway hyperresponsiveness and NF-κB signaling pathway in a mouse model of allergic airway disease

The root of Peucedanum praeruptorum Dunn is a traditional Chinese medicine commonly used to treat asthma in China. (±)-praeruptorin A (PA) is the most abundant constituent of P. praeruptorum Dunn, the effects of which on asthma were investigated using a murine model of allergic airway disease. BALB/c mice were sensitized and challenged by ovalbumin to induce airway inflammation. PA was administered intragastrically before every OVA challenge. Airway responsiveness was measured by a lung function analysis system. The number of total leukocytes in bronchoalveolar lavage fluid was counted using a hemocytometer, and differential cell counts were determined using Diff-Quick-stained smears. Histopathology of lung tissue was analyzed by hematoxylin-eosin and Congo red staining. Levels of inflammatory mediators in bronchoalveolar lavage fluid and immunoglobulins in serum were measured by enzyme-linked immunosorbent assay. The expression of pulmonary eotaxin was detected by immunohistochemistry and reverse transcription polymerase chain reaction. The activation of NF-κB was evaluated by electrophoretic mobility shift assay and western blot analysis. Compared with model group, PA significantly reduced airway hyperresponsiveness and airway eosinophilic inflammation, improved pathologic lesion of the lungs, reduced levels of interleukin (IL)-4, IL-5, IL-13 and LTC₄ in bronchoalveolar lavage fluid and immunoglobulin (Ig) E in serum, and inhibited eotaxin protein and mRNA expression, IκBα degradation, NF-κB nuclear translocation, NF-κB DNA-binding activity and RelA/p65 phosphorylation in lung, which suggested that PA can significantly suppress OVA-induced airway inflammation and airway hyperresponsiveness in mice, showing great therapeutic potential for the treatment of allergic asthma.

Astragalin attenuates lipopolysaccharide-induced inflammatory responses by down-regulating NF-κB signaling pathway

Astragalin (AG), a flavonoid from many traditional herbs and medicinal plants, has been described to exhibit in vitro anti-inflammatory activity. The present study aimed to determine the protective effects and the underlying mechanisms of astragalin on lipopolysaccharide-induced endotoxemia and lung injury in mice. Mice were injected intraperitoneally (i.p.) with lipopolysaccharide (LPS) (dose range: 5-40 mg/kg). We observed mice on mortality for 7 days twice a day and recorded survival rates. In drug testing, we examined the therapeutic effects of astragalin (25, 50 or 75 mg/kg) on LPS- induced endotoxemia by dosing orally astragalin 1 hour before LPS challenge. Using an experimental model of LPS-induced acute lung injury (ALI), we examined the effect of astragalin in resolving lung injury. The investigations revealed that pretreatment with astragalin can improve survival during lethal endotoxemia and attenuate inflammatory responses in a murine model of lipopolysaccharide-induced acute lung injury. The mechanisms by which Astragalin exerts its anti-inflammatory effect are correlated with inhibition of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) production via inactivation of NF-κB.

Mechanism of acute lung injury due to phosgene exposition and its protection by cafeic acid phenethyl ester in the rat

The mechanism of phosgene-induced acute lung injury (ALI) remains unclear and it is still lack of effective treatments. Previous study indicated that oxidative stress was involved in phosgene-induced ALI. Caffeic acid phenethyl ester (CAPE) has been proved to be an anti-inflammatory agent and a potent free radical scavenger. The purpose of this study was to investigate the protective effects of CAPE on phosgene-induced ALI and identify the mechanism, in which oxidative stress and inflammation were involved. The phosgene was used to induce ALI in rats. The results showed that after phosgene exposure, total protein content in BALF was not significantly changed. The increase of MDA level and SOD activity induced by phosgene was significantly reduced by CAPE administration, and the decrease of GSH level in BALF and lung were significantly reversed by CAPE. CAPE also partially blocked the translocation of NF-κB p65 to the nucleus, but it had little effect on the phosphorylation of p38 MAPK. In conclusion, CAPE showed protective effects on lung against phosgene-induced ALI, which may be related with a combination of the antioxidant and anti-inflammatory functions of CAPE.

Evidences of protective potentials of microdoses of ultra-high diluted arsenic trioxide in mice receiving repeated injections of arsenic trioxide

The present study was undertaken to examine if microdoses of ultra-high diluted arsenic trioxide (a potentized homeopathic remedy, Arsenicum Album 200C, diluted 10(-400) times) have hepatoprotective potentials in mice subjected to repeated injections of arsenic trioxide. Arsenic intoxicated mice were divided into: (i) those receiving Arsenicum Album-200C daily, (ii) those receiving the same dose of diluted succussed alcohol (Alc 200C) and (iii) another group receiving neither drug nor succussed alcohol. Two other control groups were also maintained: one fed normal diet only and the other receiving normal diet and Alc-200C. Toxicity biomarkers like aspartate and alanine aminotransferases, glutathione reductase, catalase, succinate dehydrogenase, superoxide dismutase and reduced glutathione contents were periodically assayed keeping the observer "blinded". Additionally, electron microscopic studies and gelatin zymography for matrix metalloproteinases of liver tissues were made at day 90 and 120. Blood glucose, hemoglobin, estradiol and testosterone contents were also studied. Compared to controls, Arsenicum Album-200C fed mice showed positive modulations of all parameters studied, thereby providing evidence of protective potentials of the homeopathic drug against chronic arsenic poisoning.

The effect of interleukin-18 on airway inflammation in asthmatic murine models and its mechanisms

In order to investigate the effect of interleukin-18 (IL-18) on airway inflammation in asthmatic murine models and its mechanisms, BALB/C mice were randomly divided into three groups (n=10 in each group): group A (control group); group B (asthmatic model group); group C (IL-18-treated group). The asthmatic model was established in groups B and C by respiratory syncytial virus (RSV) killed by ultraviolet. Saline solution (0.1 mL) and IL-18 (0.1 mL, 1 microg) were intraperitoneally injected respectively in groups B and C at 7 time points (day 1, 2, 7, 8, 9, 21, 22). The number of eosinophils (EOS) and plasmacytes in the airway was observed. The levels of interferon gamma (IFN-gamma) in bronchoalveolar lavage fluid (BALF) were measured by ELISA. The results showed that symptoms of asthma in group C were more severe than in groups A and B. In group A, there were no EOS and plasmacytes in the airway submucosa. The number of EOS [15+/-3 (average cell counts per microscopic visual field, the same below)] and plasmacytes (10+/-2) in group B were increased significantly. However, the number of EOS and plasmacytes in group C (6+/-2 and 2+/-1, respectively) was decreased significantly as compared with group B (both P<0.05). The levels of IFN-gamma in groups A, B and C were 31+/-3, 40+/-5 and 63+/-5 pg/mL respectively, and those in group C were significantly higher than in groups A and B (both P<0.05). It was suggested that the mechanism by which IL-18 inhibited the airway inflammation in asthmatic mice might be contributed to the fact that IL-18 could induce the induction of IFN-gamma.

Arsenic trioxide reduces 2,4,6-trinitrobenzene sulfonic acid-induced murine colitis via nuclear factor-κB down-regulation and caspase-3 activation

Arsenic trioxide, As 2O3, already used in human anti-cancer therapy, is also an efficient agent against the autoimmune and inflammatory diseases developed in MRL/lpr mice. Inflammatory bowel diseases (IBDs), notably Crohn’s disease, which remain without efficient treatment, display autoimmune and inflammatory components. We, therefore, hypothesized that As2O 3 may be active on IBDs. Using the 2,4,6-trinitrobenzene sulfonic acid-induced murine model of colitis, we demonstrate that As2O3 used either in a preventive or a curative mode markedly reduced the induced colitis as assessed by macroscopic and microscopic scores, leading to prolonged mice survival. In addition, As2O3 was able to inhibit NF-κB expression and DNA-binding in colon extracts leading to decreased cytokine gene expression (i.e. tumor necrosis factor-α, interleukin(IL)-1β, IL-12, IL-17, IL-18, and IL-23). Interestingly, As2O3 also reduced keratinocyte-derived chemokine (KC), inducible nitric oxide synthase (iNOS) mRNA levels, and myeloperoxidase (MPO) protein expression suggesting an impairment of neutrophils. This was associated with a marked increase of procaspase-3 and induced caspase-3 activation. This caspase-3 co-localized with MPO in the remaining neutrophils suggesting that As2O 3 might have eliminated inflamed cells probably by inducing their apoptosis. These results assessed the potent anti-inflammatory effect of As2O 3, that targets both NF-κB and caspase-3 pathways, and suggests a therapeutic potential for Crohn’s disease and other severe IBDs.

Arsenic trioxide alleviates airway hyperresponsiveness and eosinophilia in a murine model of asthma

Asthma is one of the most common chronic airway inflammatory diseases. The clinical hallmarks of asthma include elevated serum levels of immunoglobulin E (IgE), eosinophilic inflammation and airway hyper-responsiveness (AHR). Arsenic trioxide (As2O3) is considered a carcinogen; however, it has also been used to treat diseases, such as syphilis, in traditional Chinese and Western medicine. Today, As2O3 is used as one of the standard therapies for acute promyelocytic leukemia (APL). Previous studies have indicated that As2O3 can induce apoptosis in eosinophils. However, the effect of As2O3 on asthma has not been investigated. We used ovalbumin (OVA)-immunized mice as a model for asthma and treated mice with As2O3 at doses of 2.5 and 5 mg/kg. The mice were then monitored for OVA-specific IgE production, airway inflammatory cell infiltration and AHR. We found that administration of As2O3 in OVA-immunized mice abrogated airway eosinophil recruitment by downregulating eotaxin expression but did not alter serum IgE or IL-5 levels in bronchoalveolar lavage fluid (BALF). Furthermore, the development of AHR and cellular infiltration into the airway were reduced by treating mice with As2O3. In vitro data suggested that low concentrations of As2O3 could induce only a small degree of apoptosis in primary pulmonary cells but could significantly inhibit the secretion of eotaxin by these cells. These results indicate that the administration of As2O3 to OVA-immunized mice can suppress lung allergic inflammatory responses. As2O3 might therefore have therapeutic potential in treating allergic airway inflammatory diseases.

Nuclear factor kappa B pathway down-regulates aquaporin 5 in the nasal mucosa of rats with allergic rhinitis

Nuclear factor kappa B (NF-κB) induces gene transcription by binding CREB-binding protein (CBP). The aim of the study was to detect the mechanisms by which NF-κB pathway regulated aquaporin 5 (AQP5) in the nasal mucosa of rats with allergic rhinitis (AR). Rats were divided into control (group C), model (group M), low-dose proline dithiocarbamate (PDTC) (group L) and high-dose PDTC (group H) groups. AR model was established by the sensitization with ovalbumin, then groups L and H were treated with PDTC (50 or 100 mg/kg/day) for 5 days. AQP5, interleukin-1β, NF-κBp65 and phosphorylated cAMP-response element binding protein (p-CREB) were detected by immunohistochemistry, Western blotting or real-time PCR. AQP5 expression in group M was lower than in group C, but in groups L and H it increased. NF-κBp65 expression in group M was higher than group C, but in groups L and H it reduced. p-CREB expression in group M was lower than group C, but in groups L and H it increased. Interleukin-1β gene level in group M was higher than group C, but in groups L and H it was lower. These data show that the NF-κB pathway could down-regulate AQP5 by interleukin-1β which inhibited CREB phosphorylation or by NF-κBp65 which competitively bound CBP.

Effects of arsenic trioxide on the cerulein-induced AR42J cells and its gene regulation

OBJECTIVES

To study the molecular mechanism of arsenic trioxide-induced cell death on cerulein-stimulated AR42J cells.

METHODS

AR42J cells were incubated for 24 hours, and cerulein (10 nmol/L) and different concentrations of arsenic trioxide were added for another 24 hours. The cells were collected and analyzed for apoptosis and oncosis by using rhodamine 123 and propidium iodide staining, and the changes in the genes that related to cell death were detected by a gene chip.

RESULTS

After cerulein stimulation, apoptosis was significantly increased in the AR42J cells. The addition of arsenic trioxide increased the number of apoptotic cells, and the apoptotic index reached its peak in the 1-micromol/L group. Regarding oncosis, low concentrations of arsenic trioxide (0.5, 1, 2, and 4 micromol/L) reduced the development of oncosis, and in the 2-micromol/L group, it was most significant, whereas high concentration of arsenic trioxide (8 micromol/L) promoted the development of oncosis. A total of 96 genes related to apoptosis were detected, and 36 genes were differentially expressed.

CONCLUSIONS

Appropriate concentrations of arsenic trioxide can induce apoptosis in AR42J cells that were induced by cerulein and lead to changes in the expressions of certain genes.

Low-dose arsenic compromises the immune response to influenza A infection in vivo

BACKGROUND

Arsenic exposure is a significant worldwide environmental health concern. We recently reported that 5-week exposure to environmentally relevant levels (10 and 100 ppb) of As in drinking water significantly altered components of the innate immune response in mouse lung, which we hypothesize is an important contributor to the increased risk of lung disease in exposed human populations.

OBJECTIVES

We investigated the effects of As exposure on respiratory influenza A (H1N1) virus infection, a common and potentially fatal disease.

METHODS

In this study, we exposed C57BL/6J mice to 100 ppb As in drinking water for 5 weeks, followed by intranasal inoculation with a sub lethal dose of influenza A/PuertoRico/8/34 (H1N1) virus. Multiple end points were assessed postinfection.

RESULTS

Arsenic was associated with a number of significant changes in response to influenza, including an increase in morbidity and higher pulmonary influenza virus titers on day 7 post-infection. We also found many alterations in the immune response relative to As-unexposed controls, including a decrease in the number of dendritic cells in the mediastinal lymph nodes early in the course of infection.

CONCLUSIONS

Our data indicate that chronic As exposure significantly compromises the immune response to infection. Alterations in response to repeated lung infection may also contribute to other chronic illnesses, such as bronchiectasis, which is elevated by As exposure in epidemiology studies.

Targeted NF-kappaB inhibition of asthmatic serum-mediated human monocyte-derived dendritic cell differentiation in a transendothelial trafficking model

Transendothelial trafficking model mimics in vivo differentiation of monocytes into dendritic cells (DC). The serum from patients with systemic lupus erythematosus promotes the differentiation of monocytes into mature DC. We have shown that selective inhibition of NF-kappaB by adenoviral gene transfer of a novel mutated IkappaBalpha (AdIkappaBalphaM) in DC contributes to T cell tolerance. Here we demonstrated for the first time that asthmatic serum facilitated human monocyte-derived DC (MDDC) maturation associated with increased NF-kappaB activation in this model. Furthermore, selective blockade of NF-kappaB by AdIkappaBalphaM in MDDC led to increased apoptosis, and decreased levels of CD80, CD83, CD86, and IL-12 p70 but not IL-10 in asthmatic serum-stimulated MDDC, accompanied by reduced proliferation of T cells. These results suggest that AdIkappaBalphaM-transferred MDDC are at a more immature stage which is beneficial to augment the immune tolerance in asthma.

Tumor necrosis factor-alpha (TNF-alpha) induces upregulation of RhoA via NF-kappaB activation in cultured human bronchial smooth muscle cells

RhoA plays an important role in Ca(2+) sensitization of bronchial smooth muscle in antigen-induced airway hyperresponsiveness (AHR). Tumor necrosis factor-alpha (TNF-alpha), a major proinflammatory cytokine, is capable of inducing AHR, but the mechanisms for this are still unknown. In the present study, the effect of TNF-alpha on RhoA protein expression was examined in cultured human bronchial smooth muscle cells (hBSMCs). To investigate the role of NF-kappaB in the TNF-alpha-induced upregulation of RhoA, the effects of an inhibitor of IkappaB kinase (IKK), BMS-345541, were also determined. Both immunoblot and immunocytochemical analyses revealed that incubation of the hBSMCs with TNF-alpha caused an activation of NF-kappaB (determined by a translocation of p65 proteins to nuclei): the peak response was observed when cells were incubated with 10 ng/mL of TNF-alpha for 30 min. An upregulation of RhoA protein was also observed at 12 - 24 h after the incubation with TNF-alpha (10 ng/mL). Both the activation of NF-kappaB and upregulation of RhoA were concentration-dependently inhibited by the co-incubation with BMS-345541. These results suggest that TNF-alpha-induced upregulation of RhoA might be mediated by an activation of NF-kappaB in hBSMCs.

Chronic exposure to arsenic in the drinking water alters the expression of immune response genes in mouse lung

BACKGROUND

Chronic exposure to drinking water arsenic is a significant worldwide environmental health concern. Exposure to As is associated with an increased risk of lung disease, which may make it a unique toxicant, because lung toxicity is usually associated with inhalation rather than ingestion.

OBJECTIVES

The goal of this study was to examine mRNA and protein expression changes in the lungs of mice exposed chronically to environmentally relevant concentrations of As in the food or drinking water, specifically examining the hypothesis that As may preferentially affect gene and protein expression related to immune function as part of its mechanism of toxicant action.

METHODS

C57BL/6J mice fed a casein-based AIN-76A defined diet were exposed to 10 or 100 ppb As in drinking water or food for 5-6 weeks.

RESULTS

Whole genome transcriptome profiling of animal lungs revealed significant alterations in the expression of many genes with functions in cell adhesion and migration, channels, receptors, differentiation and proliferation, and, most strikingly, aspects of the innate immune response. Confirmation of mRNA and protein expression changes in key genes of this response revealed that genes for interleukin 1beta, interleukin 1 receptor, a number of toll-like receptors, and several cytokines and cytokine receptors were significantly altered in the lungs of As-exposed mice.

CONCLUSIONS

These findings indicate that chronic low-dose As exposure at the current U.S. drinking-water standard can elicit effects on the regulation of innate immunity, which may contribute to altered disease risk, particularly in lung.