Comparison of inhibitory activities of zinc oxide ultrafine and fine particulates on IgE-induced mast cell activation

Anticancer activity of zinc oxide nanoparticles on prostate and colon cancer cell line

Introduction

Considering the numerous drug resistance in cancer and the advancement of science in nanomedicines, it was decided to compare the effectiveness of zinc oxide nanoparticles in colon and prostate cell lines. Considering the importance of factors and Oxidative stress pathways in cancer prevention, the aim of the study is based on oxidative stress mechanisms.

Methodes

In order to evaluate the effects of zinc oxide nanoparticles on colon and prostate cell lines, oxidative stress factors ROS, MDA, and GSH and mitochondrial function were evaluated. The data was analyzed with Prism v8 software, and the significance level was considered to be P < 0.05.

Results

The results showed that nanoparticles induce ROS and reduce intracellular glutathione by destroying and disrupting mitochondrial function, and by increasing ROS production, damage to the lipid membrane and an increase in MDA were also evident. This effect was dose-dependent and the greatest at a concentration of 25 μg/mL. Also, ZnO nanoparticles performed better in the HT29 cell line than in the PC3 cell line.

Conclusion

This study showed that exposure of HT29 and PC3 cancer cells to zinc oxide nanoparticles at different concentrations inhibited growth by cytotoxic effects.

Antimicrobial mechanism of cuprous oxide (Cu2O) coatings

Some very effective antimicrobial coatings exploit copper or cuprous oxide (Cu2O) as the active agent. The aim of this study is to determine which species is the active antimicrobial - dissolved ions, the Cu2O solid, or reactive oxygen species. Copper ions were leached from Cu2O into various solutions and the leachate tested for both dissolved copper and the efficacy in killing Pseudomonas aeruginosa. The concentration of copper species leached from Cu2O into aqueous solution varied greatly with the composition of the aqueous solution. For a range of solution buffers, killing of P. aeruginosa was highly correlated with the concentration of copper in the leachate. Further, 10 µL bacterial suspension droplets were placed on Cu2O coatings, with or without a polymer barrier layer, and tested for bacterial kill. Killing occurred without contact between bacterium and solid, demonstrating that contact with Cu2O is not necessary. We therefore conclude that soluble copper species are the antimicrobial agent, and that the most potent species is Cu+. The solid quickly raises and sustains the concentration of soluble copper species near the bacterium. Killing via soluble copper ions rather than contact should allow copper coatings to kill bacteria even when fouled, which is an important practical consideration.

Immunomodulatory zinc-based materials for tissue regeneration

Zinc(Zn)-based materials have contributed greatly to the rapid advancements in tissue engineering. The qualities they possess that make them so beneficial include their excellent biodegradability, biocompatibility, anti-bacterial activity, among and several others. Biomedical materials that act as a foreign body, will inevitably cause host immune response when introduced to the human body. As the osteoimmunology develops, the immunomodulatory characteristics of biomaterials have become an appealing concept to improve implant-tissue interaction and tissue restoration. Recently, Zn-based materials have also displayed immunomodulatory functions, especially macrophage polarization states. It can promote the transformation of M1 macrophages into M2 macrophages to enhance the tissue regeneration and reconstruction. This review covers mainly Zn-based materials and their characteristics, including metallic Zn alloys and Zn ceramics. We highlight the current advancements in the type of immune responses, as well as the mechanisms, that are induced by Zn-based biomaterials, most importantly the regulation of innate immunity and the mechanism of promoting tissue regeneration. To this end, we discuss their applications in biomedicine, and conclude with an outlook on future research challenges.

The Possible Uses and Challenges of Nanomaterials in Mast Cell Research

Mast cells are tissue-resident immune cells that are involved in inflammation and fibrosis but also serve beneficial roles, including tissue maintenance, angiogenesis, pathogen clearance, and immunoregulation. Their multifaceted response and the ability of their mediators to target multiple organs and tissues means that mast cells play important roles in numerous conditions, including asthma, atopic dermatitis, drug sensitivities, ischemic heart disease, Alzheimer disease, arthritis, irritable bowel syndrome, infections (parasites, bacteria and viruses), and cancer. As a result, mast cells have become an important target for drug discovery and diagnostic research. Recent work has focused on applying novel nanotechnologies to explore cell biology. In this brief review, we will highlight the use of nanomaterials to modify mast cell functions and will discuss the potential of these technologies as research tools for understanding mast cell biology.

Metal nanomaterials: Immune effects and implications of physicochemical properties on sensitization, elicitation, and exacerbation of allergic disease

The recent surge in incorporation of metallic and metal oxide nanomaterials into consumer products and their corresponding use in occupational settings have raised concerns over the potential for metals to induce size-specific adverse toxicological effects. Although nano-metals have been shown to induce greater lung injury and inflammation than their larger metal counterparts, their size-related effects on the immune system and allergic disease remain largely unknown. This knowledge gap is particularly concerning since metals are historically recognized as common inducers of allergic contact dermatitis, occupational asthma, and allergic adjuvancy. The investigation into the potential for adverse immune effects following exposure to metal nanomaterials is becoming an area of scientific interest since these characteristically lightweight materials are easily aerosolized and inhaled, and their small size may allow for penetration of the skin, which may promote unique size-specific immune effects with implications for allergic disease. Additionally, alterations in physicochemical properties of metals in the nano-scale greatly influence their interactions with components of biological systems, potentially leading to implications for inducing or exacerbating allergic disease. Although some research has been directed toward addressing these concerns, many aspects of metal nanomaterial-induced immune effects remain unclear. Overall, more scientific knowledge exists in regards to the potential for metal nanomaterials to exacerbate allergic disease than to their potential to induce allergic disease. Furthermore, effects of metal nanomaterial exposure on respiratory allergy have been more thoroughly-characterized than their potential influence on dermal allergy. Current knowledge regarding metal nanomaterials and their potential to induce/exacerbate dermal and respiratory allergy are summarized in this review. In addition, an examination of several remaining knowledge gaps and considerations for future studies is provided.

A review on anti-inflammatory activity of green synthesized zinc oxide nanoparticle: Mechanism-based approach

Inflammation plays a very important role in the pathogenesis of various diseases like atherosclerosis, rheumatoid arthritis, asthma, and cancer. Lack of anti-inflammatory drugs and vectors provokes the need for developing new molecules for the management of inflammatory disorders. Nanotechnology has emerged as a wonderful research area in the past decade owing to its enhanced properties than bulk counterparts. This paper discusses the green synthesis of zinc oxide nanoparticle (ZnO NPs) and various characterization tools employed to comprehend the physiochemical properties of nanoparticles. ZnO NPs interaction with cells and its pharmacokinetic behavior inside the cells has also been discussed. The anti-inflammatory activity of ZnO NPs has been elucidated with the mechanism-based approach. A concise literature review has been included which summarizes the size, shape of ZnO NPs and the inflammatory model used for analyzing the anti-inflammatory activity of ZnO NPs. ZnO NPs potential offering towards anti-inflammatory activity like stable nature, selective targeting has been discussed briefly. The present study highlights the potential of ZnO NPs as an anti-inflammatory drug molecule or a vector for drug delivery.

Mechanism of Anti-bacterial Activity of Zinc Oxide Nanoparticle Against Carbapenem-Resistant Acinetobacter baumannii

Acinetobacter baumannii is a multi-drug resistant opportunistic pathogen, which causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Carbapenems (beta-lactam) are most effective antibiotics till now against A. baumannii, but the development of resistance against it may lead to high mortality. Therefore, it is of utmost importance to develop an alternative drug against A. baumannii. In the present study, we have synthesized ZnO nanoparticle (ZnO-NP) and characterized by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and UV-Visible spectroscopy. Prepared ZnO-NPs have the size of 30 nm and have different characteristics of ZnO-NPs. Growth kinetics and disk diffusion assay showed that ZnO-NP demonstrated good antibacterial activity against carbapenem resistant A. baumannii. We have also investigated the mechanism of action of ZnO-NPs on the carbapenem resistant strain of A. baumannii. The proposed mechanism of action of ZnO involves the production of reactive oxygen species, which elevates membrane lipid peroxidation that causes membrane leakage of reducing sugars, DNA, proteins, and reduces cell viability. These results demonstrate that ZnO-NP could be developed as alternative therapeutics against A. baumannii.

Low toxicity and accumulation of zinc oxide nanoparticles in mice after 270-day consecutive dietary supplementation

The toxicity and accumulation of zinc oxide nanoparticles (ZnO-NPs), ZnO microparticles (ZnO-MPs) and Zn ions were evaluated after long-term feeding with zinc-replenished food (1600 mg zinc equivalent per kg food) for 270 consecutive days. It was difficult for ZnO-NPs, ZnO-MPs and Zn ions were difficult to pass through the intestine barrier, and most of them were excreted mainly through feces. The distribution results showed that there was no noticeable difference among the distribution profiles of ZnO-NPs, ZnO-MPs and Zn ions in mice. Zn accumulated only in the digestive tract organs after the exposure to all three samples. However, the biomedical parameters and pathological investigations showed liver lesions induced by ZnO-MPs, but fewer by ZnO-NPs or Zn ions. The reason for the remarkably low in vivo toxicity of ZnO-NPs is discussed. Our findings suggest that ZnO-NPs are relatively biocompatible as the nutritional additive at the commonly used dose.

Aluminum-doped zinc oxide nanoparticles attenuate the TSLP levels via suppressing caspase-1 in activated mast cells

Zinc oxide nanoparticles (ZO-NPs) are used as antimicrobials, anti-inflammatories, and to treat cancer. However, although ZO-NPs have excellent efficiency and specificity, their cytotoxicity is higher than that of micron-sized zinc oxide. Doping ZO-NPs with aluminum can improve therapeutic efficacy, but the biological effects and mechanisms involved have not been elucidated. Here, we reported the efficacy of aluminum-doped ZO-NP (AZO) on thymic stromal lymphopoietin (TSLP) production and caspase-1 activation in human mast cell line, HMC-1 cells. AZO significantly reduced TSLP levels as well as interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α without inducing cytotoxicity. Furthermore, AZO more effectively reduced TSLP, IL-6, IL-8, and TNF-α levels than ZO-NP. The levels of inflammatory cytokine mRNA were also reduced by AZO treatment. AZO blocked production of IL-1β and activations of caspase-1 and nuclear factor-κB by inhibiting IκB kinase β and receptor interacting protein 2. In addition, AZO attenuated phosphorylation of mitogen-activated protein kinases, such as extracellular signal-regulated kinase, c-Jun N-terminal kinases, and p38. These findings provide evidence that AZO improves anti-inflammatory properties and offer a safe and effective potential treatment option.

Establishment of a Mouse Anti-ovalbumin IgE Monoclonal Antibody That Induces FcɛRII (CD23)-dependent Activation Without FcɛRI-Dependent Activation

IgE mainly activates cells via two receptors, FcɛRI and FcɛRII. Blocking antibodies against and animals genetically targeted for these receptors have been successfully used to distinguish between these two activating pathways. In the present study, we investigated whether our newly established anti-ovalbumin (OVA) monoclonal IgE OE-2 induced FcɛRII-dependent activation, but not FcɛRI-dependent activation in vivo and in vitro, in contrast to the previously established anti-OVA IgE OE-1, which stimulated FcɛRI and FcɛRII. The FcɛRI-mediated degranulation of RBL2H3 cells and passive systemic anaphylaxis in mice were induced by OE-1 but not OE-2. On the other hand, the production of nitric oxide by rat peritoneal macrophages and the primary antibody response in mice against co-injected OVA, which were mediated through FcɛRII, were induced and enhanced by OE-1 and OE-2. Differences in the epitopes recognized by OE-1 and OE-2 may partially explain why OE-1, but not OE-2, triggered FcɛRI-dependent activation. OE-1 bridged FcɛRI through effective aggregation with OVA, whereas OE-2 crosslinked the receptor strongly and only moderately upon the addition of an anti-kappa antibody and polymerized OVA, namely, an OVA-conjugated resin, respectively, resulting in degranulation. Our results offer a novel approach for determining the relative importance of FcɛRI and FcɛRII in various IgE-dependent responses by using OE-1 and OE-2.

Biological reactivity of zinc oxide nanoparticles with mammalian test systems: an overview

Zinc oxide nanoparticles (ZnO NPs) have useful physicochemical advantages, and are used extensively. This has raised concerns regarding their potential toxicity. ZnO NP attributes that contribute to cytotoxicity and immune reactivity, however, seem to vary across literature considerably. Largely, dissolution and generation of reactive oxygen species appear to be the most commonly reported paradigms. Moreover, ZnO NP size and shape may also contribute toward their overall nano-bio interactions. Analysis is further complicated by factors such as adsorption of proteins on the NP surface, which may influence their bioreactivity. The main aim of this review is to give a systematic overview of the postulates explaining cytotoxic, inflammatory and genotoxic effects of ZnO NPs when exposed to different types of cells in vitro and in vivo.

Therapeutic Potential of Monoclonal IgA Antibodies in Allergic Diseases: Suppressive Effect of IgA on Immune Responses Induced By Re-exposure to Antigen in Sensitized Mice by Monoclonal IgE Antibody That Binds to a Different Epitope of the Same Antigen

Repeated exposure to an allergen induces allergic symptoms by activating mast cells that express anti-allergen IgE, which results in further sensitization to an allergen. Considering that additional sensitization elicits more severe allergic reactions upon the next allergen challenge, suppression of the boosting phase represents an efficacious way to prevent and ameliorate allergic diseases. In this study, we investigated the therapeutic potential of allergen-specific monoclonal IgA on allergic diseases. This antibody acts by decreasing immune responses upon exposure to allergens in mice previously sensitized by a monoclonal IgE that recognizes the allergen. The lack of inhibitory effects of anti-ovalbumin monoclonal IgA (OA-4) on either the binding of anti-ovalbumin monoclonal IgE (OE-1) to ovalbumin by ELISA or on ovalbumin-induced degranulation of rat basophilic leukemia RBL2H3 cells sensitized with OE-1 indicated that OA-4 and OE-1 recognized different epitopes on ovalbumin. Immune responses (anti-ovalbumin IgG1 production and cytokine release from splenocytes) induced by intravenous ovalbumin challenge in DBA/1J mice passively sensitized with OE-1 were inhibited by intravenous injection of OA-4 15 min before challenge without affecting anaphylaxis. Moreover, OA-4 injection 1 h after ovalbumin challenge also effectively suppressed immune responses. The achievement of immunosuppression by IgA injection occurred even after allergen challenge in mice in an epitope-independent fashion. These findings suggest that monoclonal IgA administered at the time of hospitalization of a patient with allergic symptoms, who was already exposed to the allergen in the presence of IgE recognizing an undefined epitope(s) on the allergen, should effectively relieve allergic disease through its immunosuppressive effects.

Influence of physicochemical properties of silver nanoparticles on mast cell activation and degranulation

Silver nanoparticles (AgNPs) are increasingly being incorporated into products for their antimicrobial properties. This has resulted in increased human exposures and the possibility of adverse health effects. Mast cells orchestrate allergic immune responses through degranulation and release of pre-formed mediators. Little data exists on understanding interactions of AgNPs with mast cells and the properties that influence activation and degranulation. Using bone marrow-derived mast cells and AgNPs of varying physicochemical properties we tested the hypothesis that AgNP physicochemical properties influence mast cell degranulation and osteopontin production. AgNPs evaluated included spherical 20 nm and 110 nm suspended in either polyvinylpyrrolidone (PVP) or citrate, Ag plates suspended in PVP of diameters between 40–60 nm or 100–130 nm, and Ag nanowires suspended in PVP with thicknesses <100 nm and length up to 2 μm. Mast cell responses were found to be dependent on the physicochemical properties of the AgNP. Further, we determined a role for scavenger receptor B1 in AgNP-induced mast cell responses. Mast cell degranulation was not dependent on AgNP dissolution but was prevented by tyrosine kinase inhibitor pretreatment. This study suggests that exposure to AgNPs may elicit adverse mast cell responses that could contribute to the initiation or exacerbation of allergic disease.

Engineered nanomaterial exposure and the risk of allergic disease

PURPOSE OF REVIEW

Although the production and use of engineered nanomaterials (ENMs) is rapidly increasing, we lack sufficient knowledge regarding their capacity to induce and/or promote allergic disease. As novel ENMs are being developed and used for biomedical applications, such as drug delivery, it will be critical to understand the relationship between physicochemical properties of ENMs and possible mechanisms of immunomodulation.

RECENT FINDINGS

Cellular studies and a few animal studies have begun to examine the immunomodulatory effects of ENM exposure that may be predictive of developing allergic reactions. Specifically, the effects of direct ENM exposure on key immune cells recognized to facilitate allergic disease has been evaluated and will be discussed. However, few studies have reported specific physicochemical properties of ENMs that initiate allergic immune responses. Although limited, these descriptive studies point to the induction of cellular mechanisms that are well known to promote allergic disease.

SUMMARY

The limited data currently available suggest that there is a potential risk for the development of allergic responses following exposure to ENMs. As more ENMs are developed for consumer products and nanomedicines, further study on their potential for adverse immune interactions will be necessary for safe implementation of these novel materials.

Remission of food allergy by the Janus kinase inhibitor ruxolitinib in mice

To clarify the role of Janus kinase (JAK) in and the efficacy of JAK inhibitors on food allergy, we investigated the effect of the clinically available JAK inhibitor ruxolitinib on mouse food allergy and the functions of cultured mast cells in vitro. Anaphylactic symptoms including diarrhea and decreases in body temperature pursuant to oral ovalbumin (OVA) challenges in food allergy mice were attenuated by the daily oral administration of ruxolitinib. This drug inhibited increases in mouse mast cell protease-1 concentrations in the serum and mast cell numbers in the intestines of these mice as well as degranulation, IL-13 production, and the spontaneous and IL-9-dependent survival of mouse bone marrow-derived mast cells in spite of the absence of an effect of ruxolitinib on passive systemic anaphylaxis. Anti-OVA IgG2a, IgE, and IgG1 serum levels and the release of IFN-γ, IL-4, IL-9, and IL-10 from the OVA-restimulated splenocytes of food allergy mice were also decreased by the treatment. Moreover, ruxolitinib administration to mice that had already exhibited anaphylactic responses to previous challenges reduced anaphylactic responses to further oral OVA challenges, which suggested that ruxolitinib has a therapeutic potential on food allergy. Our results showed that ruxolitinib remitted food allergy in mice mainly through immunosuppression and the prevention of mast cell hyperplasia, and partially through the inhibition of mast cell activation. We consider JAK inhibition to be a promising strategy for the prevention of food allergy, and ruxolitinib along with its derivatives inhibiting JAK as good candidates for therapeutic drugs to treat food allergy.

Manufactured and airborne nanoparticle cardiopulmonary interactions: a review of mechanisms and the possible contribution of mast cells

Human inhalation exposures to manufactured nanoparticles (NP) and airborne ultrafine particles (UFP) continues to increase in both occupational and environmental settings. UFP exposures have been associated with increased cardiovascular mortality and morbidity, while ongoing research supports adverse systemic and cardiovascular health effects after NP exposures. Adverse cardiovascular health effects include alterations in heart rate variability, hypertension, thrombosis, arrhythmias, increased myocardial infarction, and atherosclerosis. Exactly how UFP and NP cause these negative cardiovascular effects is poorly understood, however a variety of mediators and mechanisms have been proposed. UFP and NP, as well as their soluble components, are known to systemically translocate from the lung. Translocated particles could mediate cardiovascular toxicity through direct interactions with the vasculature, blood, and heart. Recent study suggests that sensory nerve stimulation within the lung may also contribute to UFP- and NP-induced acute cardiovascular alterations. Activation of sensory nerves, such as C-fibers, within the lung may result in altered cardiac rhythm and function. Lastly, release of pulmonary-derived mediators into systemic circulation has been proposed to facilitate cardiovascular effects. In general, these proposed pulmonary-derived mediators include proinflammatory cytokines, oxidatively modified macromolecules, vasoactive proteins, and prothrombotic factors. These pulmonary-derived mediators have been postulated to contribute to the subsequent prothrombotic, atherogenic, and inflammatory effects after exposure. This review will evaluate the potential contribution of individual mediators and mechanisms in facilitating cardiopulmonary toxicity following inhalation of UFP and NP. Lastly, we will appraise the literature and propose a hypothesis regarding the possible role of mast cells in contributing to these systemic effects.

Complement C3a-induced IL-17 plays a critical role in an IgE-mediated late-phase asthmatic response and airway hyperresponsiveness via neutrophilic inflammation in mice

Allergen-specific IgE plays an essential role in the pathogenesis of allergic asthma. Although there has been increasing evidence suggesting the involvement of IL-17 in the disease, the relationship between IL-17 and IgE-mediated asthmatic responses has not yet been defined. In this study, we attempted to elucidate the contribution of IL-17 to an IgE-mediated late-phase asthmatic response and airway hyperresponsiveness (AHR). BALB/c mice passively sensitized with an OVA-specific IgE mAb were challenged with OVA intratracheally four times. The fourth challenge caused a late-phase increase in airway resistance associated with elevated levels of IL-17(+)CD4(+) cells in the lungs. Multiple treatments with a C3a receptor antagonist or anti-C3a mAb during the challenges inhibited the increase in IL-17(+)CD4(+) cells. Meanwhile, a single treatment with the antagonist or the mAb at the fourth challenge suppressed the late-phase increase in airway resistance, AHR, and infiltration by neutrophils in bronchoalveolar lavage fluid. Because IL-17 production in the lungs was significantly repressed by both treatments, the effect of an anti-IL-17 mAb was examined. The late-phase increase in airway resistance, AHR, and infiltration by neutrophils in bronchoalveolar lavage fluid was inhibited. Furthermore, an anti-Gr-1 mAb had a similar effect. Collectively, we found that IgE mediated the increase of IL-17(+)CD4(+) cells in the lungs caused by repeated Ag challenges via C3a. The mechanisms leading to the IgE-mediated late-phase asthmatic response and AHR are closely associated with neutrophilic inflammation through the production of IL-17 induced by C3a.

Tyrosine kinase inhibitor sunitinib relieves systemic and oral antigen-induced anaphylaxes in mice

BACKGROUND

  Systemic and oral antigen-induced anaphylaxes are mediated by immunoglobulin (Ig) E and mast cells, but there is no satisfactory treatment for the life-threatening allergic reaction. We investigated the potential of the multitargeted receptor tyrosine kinase inhibitor sunitinib to relieve anaphylactic reactions in food allergy and systemic anaphylaxis.

METHODS

  Efficacy of oral sunitinib on oral and parenteral antigen-induced anaphylaxes in Balb/c mice was evaluated. IgE-dependent degranulation and growth of rat basophilic leukemia RBL2H3 and bone marrow-derived mast cells (BMMCs) in response to sunitinib were investigated.

RESULTS

  Daily administration of sunitinib throughout antigen challenges prevented oral antigen-induced anaphylaxis including diarrhea, anaphylactic symptoms, and hypothermia. The mouse mast cell protease (MMCP)-1 concentration in serum and mast cell number in intestinal tissue after challenge were also decreased by the treatment. Spleen cells from sunitinib-treated mice contained smaller numbers of antigen-specific IgG-producing cells and secreted lower amounts of both Th1 and Th2 cytokines than those of the control mice, whereas the levels of antigen-specific antibodies in serum were not decreased. The reactions and MMCP-1 release in oral antigen-induced anaphylaxis and passive systemic anaphylaxis were attenuated even by a single predose of sunitinib. Degranulation and growth of RBL2H3 cells and BMMCs were greatly reduced by sunitinib.

CONCLUSION

  These results suggested that sunitinib relieves systemic and oral antigen-induced anaphylaxes by the prevention of mast cell activation and hyperplasia in intestinal tissue directly and indirectly through an immunosuppressive effect. Sunitinib and its related kinase inhibitors might be potential drugs for the treatment of food allergy and systemic anaphylaxis.

Aspergillus oryzae lectin induces anaphylactoid oedema and mast cell activation through its interaction with fucose of mast cell-bound non-specific IgE

We investigated whether Aspergillus oryzae lectin (AOL), a fucose-specific lectin, induces anaphylactoid reactions and mast cell activation. The injection of AOL into footpads of mice produced a dose-related acute paw oedema. The AOL-induced oedema was attenuated by predose of histamine H1 receptor blocker or pretreatment of the lectin with fucose before injection and was not observed in SCID and mast cell-deficient WBB6F1-W/Wv mice. These results suggested that the AOL-induced anaphylactoid reaction was mediated by histamine released from mast cells. In addition, the activation of mast cells was seemed to be induced by the crosslinking of IgE on the cell surface following the binding of AOL to fucose residues in IgE. Consistent with the in vivo results, AOL induced the degranulation of the rat mast cell line RBL2H3 sensitized with monoclonal IgE. As AOL induced the increase in intracellular Ca(2+) concentration of IgE-sensitized RBL2H3 cells as well as antigen stimulation, AOL could input signals from FcεRI. The degranulation of IgE-sensitized RBL2H3 cells by AOL was diminished by pretreatment of AOL with fucose. Defucosylated IgE did not induce degranulation of RBL2H3 cells in response to AOL stimulation, in spite of its ability to induce degranulation by antigen stimulation as intact IgE. These results indicated that AOL bound to fucose residue of IgE causing antigen-independent IgE-mediated mast cell activation and anaphylactoid reactions in vitro and in vivo, respectively. AOL bound to human IgE as well as to mouse IgE, suggesting the possible implication of AOL in the allergic response to Aspergillus oryzae in humans.

Establishment and characterization of a murine model for allergic asthma using allergen-specific IgE monoclonal antibody to study pathological roles of IgE

Allergen-specific IgE has long been regarded as a major molecular component of allergic asthma. Although IgE plays a central role in the early asthmatic response, its roles in the chronic phase, such as the late asthmatic response, airway hyperresponsiveness (AHR), and airway remodeling (goblet cell hyperplasia and subepithelial fibrosis) have not yet been defined well. In this study, we investigated the hypothesis that chronic responses could be induced by IgE-dependent mechanisms. BALB/c mice passively sensitized with an ovalbumin (OVA)-specific IgE monoclonal antibody (mAb) were repeatedly challenged with intratracheal administration of OVA. The first challenge induced early phase airway narrowing without any late response, but the fourth challenge caused not only an early but also a late phase response, AHR, and goblet cell hyperplasia. Macrophages, lymphocytes and neutrophils, but not eosinophils, were significantly increased in the lung 24h after the fourth challenge. Interestingly, levels of OVA-specific IgG1 in serum increased by multiple antigen challenges. A C3a receptor antagonist inhibited the late asthmatic response, AHR, and infiltration by neutrophils. In contrast, no late response, goblet cell hyperplasia, inflammatory cells, or production of IgG1 was observed in severe combined immunodeficient mice. On the other hand, seven challenges in BALB/c mice induced subepithelial fibrosis associated with infiltration by eosinophils. In conclusion, the allergic asthmatic responses induced by passive sensitization with IgE mAb can provide a useful model system to study the pathological roles of IgE in acute and chronic phases of allergic asthma.

Zinc oxide nanoparticles for selective destruction of tumor cells and potential for drug delivery applications

IMPORTANCE OF THE FIELD

Metal oxide nanoparticles, including zinc oxide, are versatile platforms for biomedical applications and therapeutic intervention. There is an urgent need to develop new classes of anticancer agents, and recent studies demonstrate that ZnO nanomaterials hold considerable promise.

AREAS COVERED IN THIS REVIEW

This review analyzes the biomedical applications of metal oxide and ZnO nanomaterials under development at the experimental, preclinical and clinical levels. A discussion regarding the advantages, approaches and limitations surrounding the use of metal oxide nanoparticles for cancer applications and drug delivery is presented. The scope of this article is focused on ZnO, and other metal oxide nanomaterial systems, and their proposed mechanisms of cytotoxic action, as well as current approaches to improve their targeting and cytotoxicity against cancer cells.

WHAT THE READER WILL GAIN

This review aims to give an overview of ZnO nanomaterials in biomedical applications.

TAKE HOME MESSAGE

Through a better understanding of the mechanisms of action and cellular consequences resulting from nanoparticles interactions with cells, the inherent toxicity and selectivity of ZnO nanoparticles against cancer may be improved further to make them attractive new anticancer agents.

Zinc in innate and adaptive tumor immunity

Zinc is important. It is the second most abundant trace metal with 2-4 grams in humans. It is an essential trace element, critical for cell growth, development and differentiation, DNA synthesis, RNA transcription, cell division, and cell activation. Zinc deficiency has adverse consequences during embryogenesis and early childhood development, particularly on immune functioning. It is essential in members of all enzyme classes, including over 300 signaling molecules and transcription factors. Free zinc in immune and tumor cells is regulated by 14 distinct zinc importers (ZIP) and transporters (ZNT1-8). Zinc depletion induces cell death via apoptosis (or necrosis if apoptotic pathways are blocked) while sufficient zinc levels allows maintenance of autophagy. Cancer cells have upregulated zinc importers, and frequently increased zinc levels, which allow them to survive. Based on this novel synthesis, approaches which locally regulate zinc levels to promote survival of immune cells and/or induce tumor apoptosis are in order.

Enhancement of FcɛRI-mediated degranulation response in the rat basophilic leukemia cell line RBL2H3 by the fluorosurfactants perfluorooctanoic acid and perfluorooctane sulfonate

The effect of two fluorosurfactants, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), on degranulation of rat basophilic leukemia RBL2H3 cells was investigated. PFOA and PFOS promoted IgE-mediated release of granule components of RBL2H3 cells at 10-300μM. At low concentrations (<30μM), the fluorosurfactants failed to induce degranulation, but promoted IgE-mediated degranulation without affecting cell viability. The absence of extracellular Ca(2+) removed the promoting effect of the fluorosurfactants on IgE-mediated degranulation. On the other hand, the fluorosurfactants at high concentrations (>100μM) induced release of granule components without IgE-mediated activation in parallel with cell death. Pretreatment of tetradecanoyl-phorbol-acetate, a protein kinase C activator, inhibited both the promoting effect of the fluorosurfactants at low concentration on IgE-mediated degranulation and cell death-associated granule component release by high concentration of the fluorosurfactants. These findings indicate that PFOA and PFOS affect granule component release of mast cells by two different mechanisms, namely enhancement of active degranulation machinery at low concentrations and cell lysis at high concentrations.