Inhibition of eosinophil migration by lactoferrin

Bamboo salt reduces allergic responses by modulating the caspase-1 activation in an OVA-induced allergic rhinitis mouse model

Bamboo salt (BS) is a specially processed salt according to the traditional recipe using sun-dried salt (SDS) and bamboo in Korea. The present study investigated the effects and mechanism of BS, SDS, NaCl, or mineral mixture (containing zinc, magnesium, and potassium) on ovalbumin (OVA)-induced allergic rhinitis (AR) animal model. The increased number of rubs was inhibited by the oral administration of BS, SDS, NaCl, mineral mixture, or nose inhalation of BS. The increased levels of IgE, histamine, and interleukin (IL)-1β in serum were reduced by BS. The level of interferon-γ was increased, whereas the level of IL-4 was reduced on the spleen tissue of BS-treated mice. In the BS-treated mice, the number of eosinophils and mast cells infiltration increased by OVA-sensitization were also decreased. Protein levels of inflammatory cytokines were reduced by BS or NaCl administration in the nasal mucosa of the AR mice. In addition, BS inhibited caspase-1 activity in the nasal mucosa tissue. In activated human mast cells, BS significantly inhibited the production of IL-1β and thymic stromal lymphopoietin and activation of caspase-1. Our data indicate that BS has anti-allergic and anti-inflammatory effects by regulating of caspase-1 activation in AR mice and in vitro models.

Lactoferrin regulates an axis involving CD11b and CD49d integrins and the chemokines MIP-1α and MCP-1 in GM-CSF-treated human primary eosinophils

Eosinophils are multifunctional immune cells that contribute to innate and adaptive immune/repair responses. Lactoferrin (LF) is an iron-binding protein indicated to alter cell adhesion and immune function by receptor-mediated interactions or by participating in redox mechanisms. The eosinophil adhesion molecules, αMβ2 and α4β1, are differentially expressed following exposure to the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) and various redox agents. We hypothesized that LF can alter the function and production of proteins involved in adhesion/migration. Utilizing eosinophil peroxidase activity or fluorescent labeling adhesion assays, LF reduced GM-CSF-induced eosinophil adhesion in the presence of fibronectin or vascular adhesion molecule-1 compared with GM-CSF treatment alone. Flow cytometric analysis of eosinophil αM (CD11b) and α4 (CD49d) integrins revealed that cotreatments (24 h) with LF plus GM-CSF induced a significant increase in CD11b compared with control and GM-CSF treatments but a significant decrease in CD49d compared with control and GM-CSF treatments. These changes in CD11b and CD49d levels were significantly correlated with the increased production of chemokines (macrophage inflammatory Protein-1α, monocyte chemotactic protein-1) and an identified increase in S100A9 production. Thus, LF release at sites of inflammation may alter eosinophil recruitment/activation and possibly the progression of diseases such as cancer and asthma where significant eosinophil influx has been described.

Association of the -33C/G OSF-2 and the 140A/G LF gene polymorphisms with the risk of chronic rhinosinusitis with nasal polyps in a Polish population

Nasal polyps are strongly associated with a risk of chronic rhinosinusitis development as well as other obstruction including asthma and allergy. The following study tested the association of the 140A/G polymorphism of lactoferine (LF) encoding gene and the -33C/G polymorphism of osteoblast-specific factor-2 (OSF-2) encoding gene with a risk of chronic rhinosinusitis with nasal polyps in a Polish population. One hundred ninety five patients of chronic rhinosinusitis with nasal polyps as well as 200 sex, age and ethnicity matched control subjects without chronic sinusitis and nasal polyps were enrolled in this study. Among the group of patients 63 subjects were diagnosed with allergy and 65 subjects with asthma, respectively. DNA was isolated from peripheral blood lymphocytes of patients as well as controls and gene polymorphisms were analyzed by restriction fragments length polymorphism polymerase chain reaction (RFLP-PCR). We reported that the 140A/G LF (OR 4.78; 95% CI 3.07-7.24), the -33C/G OSF-2 OR 3.48; 95% CI 2.19-5.52) and the -33G/G OSF-2 (OR 16.45; 95% CI 6.71-40.30) genotypes were associated with an increased risk of chronic rhinosinusitis with nasal polyps among analyzed group of patients. Moreover, the group of patients without allergy or asthma indicated the association of the -33C/G (OR 3.72; 95% CI 2.24-6.19 and OR 15.11; 95% CI 5.91-38.6) and -33G/G (OR 3.73; 95% CI 2.24-6.19 and OR 14.07; 95% CI 5.47-36.16) genotypes of the OSF-2 as wells as 140A/G (OR 3.89; 95% CI 2.40-6.31 and OR 3.62; 95% CI 2.45-5.34) genotype of OSF-2 with an increased risk of chronic rhinosinusitis with nasal polyps. Finally, it was also found that the selected group of patients with allergy or asthma indicated a very strong association of the -33C/G (OR 2.40; 95% CI 1.23-4.69 and OR 2.40; 95% CI 1.23-4.69, respectively) and -33G/G (OR 16.01; 95% CI 5.77-44.41 and OR 17.90; 95% CI 6.53-49.05, respectively) genotypes of the OSF-2 as wells as 140A/G (OR 3.22; 95% CI 1.74-6.11 and OR 3.25; 95% CI 1.75-6.04, respectively) genotypes with an increased risk of chronic rhinosinusitis with nasal polyps. Thus, our results suggest that LF and OSF-2 gene polymorphisms may have deep impact on the risk of rhinosinusitis nasal polyps' formation which may also depend on asthma or allergy. Our results showed that the 140A/G polymorphism of LF gene and the -33C/G polymorphism of the OSF-2 gene may be associated with the risk of chronic rhinosinusitis with nasal polyps in a Polish population.

Lactoferrin, a key molecule in immune and inflammatory processes

Lactoferrin (Lf) belongs to the family of antimicrobial molecules that constitute the principal defense line of nonvertebrate organisms. In human immunity, their roles are considerably extended, and actually exceed mere direct antimicrobial properties. As a result, Lf is involved in both innate and adaptive immunities where its modulating effects not only help the host fight against microbes but also protect the host against harmful effects of inflammation. Such beneficial effects have been noticed in studies using dietary Lf, without the experimenters always explaining the exact modes of action of Lf. Effects on mucosal and systemic immunities are indeed often observed, which make the roles of Lf tricky to decipher. It is now known that the immunomodulatory properties of Lf are due to its ability to interact with numerous cellular and molecular targets. At the cellular level, Lf modulates the migration, maturation, and functions of immune cells. At the molecular level, in addition to iron binding, interactions of Lf with a plethora of compounds, either soluble or cell-surface molecules, account for its modulatory properties. This paper reviews our current understanding of the mechanisms that explain the regulatory properties of Lf in immune and inflammatory processes.

Lactoferrin inhibits the growth of nasal polyp fibroblasts

The aim of this study was to evaluate the effects of lactoferrin (LF) on the growth of fibroblasts derived from nasal polyps. We showed that the proliferation of fibroblasts was inhibited in a dose-dependent manner by both native and recombinant LF. The greatest inhibition of proliferation was caused by human milk-derived, iron-saturated LF. The inhibition of fibroblast proliferation was not species specific because bovine LF also was active. The interaction between LFs and a putative cell receptor did not depend on the sugar composition of the glycan moiety of the LF molecule because lactoferrins of different origins were active and the addition of monosaccharides to the cultures did not block proliferation. However, the treatment of fibroblasts with sodium chlorate (an inhibitor of glycosaminoglycan sulfation) or the addition of heparin abolished the inhibitory effect of LF, suggesting that LF binds heparan sulfate-containing proteoglycans. The significance of LF in nasal excretions in controlling polyp formation is discussed.

Distinct effects of imperatorin on allergic rhinitis: imperatorin inhibits caspase-1 activity in vivo and in vitro

Because imperatorin (IPT), the furanocoumarins exhibits anti-inflammatory activity, we reasoned that IPT might modulate the allergic rhinitis (AR). The aim of this study was to analyze the regulation of AR by IPT. Here, we show the effect and mechanism of IPT in an ovalbumin (OVA)-induced AR model. The number of rubs after the OVA challenge in the OVA-sensitized mice was significantly higher than that in the OVA-unsensitized mice. The increased number of rubs was inhibited by the oral administration of IPT. The increased levels of IgE and histamine in the OVA-sensitized mice were reduced by IPT administration. The levels of interferon-γ were enhanced, whereas the levels of interleukin (IL)-4 were reduced on the spleen tissue of the IPT-administered AR mice. Protein levels of IL-1β, macrophage inflammatory protein-2, intercellular adhesion molecule-1, and cyclooxygenase-2 were reduced by IPT administration in the nasal mucosa of the OVA-sensitized mice. In the IPT-administered mice, the number of eosinophils and mast cells infiltration increased by OVA-sensitization were also decreased. In addition, IPT inhibited caspase-1 activity in the same nasal mucosa tissue. In activated human mast cells, the receptor-interacting protein 2 (RIP2), IκB kinase (IKK)-β, nuclear factor-κB (NF-κB)/RelA, and caspase-1 activation were increased, but increased RIP2, IKK-β, NF-κB/RelA, and caspase-1 activation were inhibited by the treatment of IPT. In addition, IPT inhibited caspase-1 activity and IL-1β production in IgE-stimulated bone marrow-derived mast cells. We can conclude that IPT exerts significant effects by regulating of caspase-1 activation in AR animal and in vitro models.

Leukocyte migratory responses to apoptosis: the attraction and the distraction

An expanding body of evidence demonstrates that cells undergoing apoptosis send out a selection of molecular navigational signals including proteins, lipids and nucleotides that serve to recruit phagocytes to the dying targets which are subsequently engulfed and removed. This homeostatic process is essentially non-phlogistic, contrasting markedly with the acute inflammatory responses elicited in phagocytes by damaging or infectious agents. The "professional" scavengers of apoptotic cells are mononuclear phagocytes-the macrophages-and sites of high-rate apoptosis are clearly characterized by macrophages associated with the apoptotic cells. By contrast, members of the other class of professional phagocytes-the granulocytes-are not recruited to sites of apoptosis as a direct consequence of the cell-death program. Indeed, recent work indicates that apoptotic cells release a mixture of migratory cues to leukocytes in order to selectively attract mononuclear phagocytes but not granulocytes through functional balancing of positive and negative signals. Here we discuss these molecular mechanisms which not only serve as migratory cues but also may activate responding phagocytes to engulf apoptotic cells effectively. Finally, we speculate upon new therapeutic opportunities these mechanisms offer for a range of pathological conditions, including inflammatory disorders and cancer.

Alleviation of allergic rhinitis symptoms with Pyeongwee-San extract (KMP6)

CONTEXT

Allergy is characterized by the overreaction of the immune system. Pyeongwee-San is a traditional Korean medicine which has been used for the treatment of the allergic disorder but the mechanism of action is not clear.

OBJECTIVE

To investigate the effect of Pyeongwee-San extract (KMP6) and its component, hesperidin (HES) in the allergic rhinitis (AR) animal model.

METHOD

We sensitized mice on 1, 5, and 14 days by intraperitoneal injections of 100 μg ovalbumin (OVA) emulsified in 20 mg of aluminum hydroxide and we challenged mice with 1.5 mg OVA. Mice received KMP6 and HES before the intranasal OVA challenge for 10 days.

RESULTS

The number of nose rubs after the OVA challenge in the OVA-sensitized mice was significantly higher than that in the OVA-unsensitized mice. The increased number of nose rub was inhibited by the oral administration of KMP6 or HES. The increased levels of IgE and histamine level in serum of the OVA-sensitized mice were reduced by KMP6 or HES administration. The level of interferon-γ was enhanced while the level of IL-4 was reduced on the spleen tissue of the KMP6 or HES-administered AR mice. Inflammatory proteins level was reduced by KMP6 or HES administration in the nasal mucosa tissue of the OVA-sensitized mice. In the KMP6 or HES-administered mice, mast cells and eosinophils infiltration increased by OVA-sensitization was decreased.

CONCLUSION

These results indicate that KMP6 and HES ameliorate the allergic inflammatory reactions such as AR.

Effect of Perilla frutescens var. acuta Kudo and rosmarinic acid on allergic inflammatory reactions

Allergy is characterized by an overreaction of the immune system. Perilla frutescens leaf extract has been reported to exhibit antiallergic inflammatory activity. To investigate precisely the effect and mechanism of 30% ethanol extract powder of P. frutescens var. acuta Kudo (EPPF) and rosmarinic acid (RA), a component of EPPF in allergic rhinitis and rhinoconjunctivitis, the antiallergic effects of EPPF and RA were analyzed using in vivo and in vitro models. Cytokine production was analyzed by means of an enzyme-linked immunosorbent assay. Cytokine expression was analyzed via reverse transcription-polymerase chain reaction and Western blotting. Transcription factor and caspase-1 activity were analyzed by a luciferase assay and caspase-1 assay, respectively. The number of nasal, ear and eye rubs after an ovalbumin (OVA) challenge in OVA-sensitized mice was significantly higher than that in OVA-unsensitized mice. Increased number of rubs was inhibited by administration of EPPF or RA. Increased levels of IgE in the serum, spleen and nasal mucosa of OVA-sensitized mice were reduced by EPPF or RA administration. The histamine level was also reduced by EPPF or RA administration in the serum of OVA-sensitized mice. Protein levels and mRNA expressions of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α were inhibited by EPPF or RA administration in the nasal mucosa tissue or spleen of OVA-sensitized mice. In EPPF or RA-administered mice, the mast cell and eosinophil infiltration increase as caused by OVA-sensitization was decreased. In addition, EPPF or RA inhibited both cyclooxygenase-2 protein expression and caspase-1 activity in the same nasal mucosa tissue. In activated human mast cells, nuclear factor-kappa B (NF-κB)/Rel A and caspase-1 activation increased, whereas NF-κB/Rel A and caspase-1 activation was inhibited after a treatment of EPPF or RA. These results indicate that EPPF and RA ameliorate allergic inflammatory reactions such as allergic rhinitis and allergic rhinoconjunctivitis.

Microenvironmental influences of apoptosis in vivo and in vitro

The apoptosis program of physiological cell death elicits a range of non-phlogistic homeostatic mechanisms-"recognition, response and removal"-that regulate the microenvironments of normal and diseased tissues via multiple modalities operating over short and long distances. The molecular mechanisms mediate intercellular signaling through direct contact with neighboring cells, release of soluble factors and production of membrane-delimited fragments (apoptotic bodies, blebs and microparticles) that allow for interaction with host cells over long distances. These processes effect the selective recruitment of mononuclear phagocytes and the specific activation of both phagocytic and non-phagocytic cells. While much evidence is available concerning the mechanisms underlying the recognition and responses of phagocytes that culminate in the engulfment and removal of apoptotic cell bodies, relatively little is yet known about the non-phagocytic cellular responses to the apoptosis program. These responses regulate inflammatory and immune cell activation as well as cell fate decisions of proliferation, differentiation and death. Here, we review current knowledge of these processes, considering especially how apoptotic cells condition the microenvironments of normal and malignant tissues. We also discuss how apoptotic cells that persist in the absence of phagocytic clearance exert inhibitory effects over their viable neighbors, paying particular attention to the specific case of cell cultures and highlighting how new cell-corpse-clearance devices-Dead-Cert Nanoparticles-can significantly improve the efficacy of cell cultures through effective removal of non-viable cells in the absence of phagocytes in vitro.

Targeting granulocyte apoptosis: mechanisms, models, and therapies

The inflammatory process is a complex series of tightly controlled cellular and biochemical events initiated by the immune system, which has evolved to eliminate or contain infectious agents and to repair damaged tissue. Apoptosis is essential for the clearance of potentially injurious inflammatory cells, such as neutrophils, eosinophils, and basophils, and the subsequent efficient resolution of inflammation. In this review, we aim to cover key features of the granulocyte life-cycle ranging from their differentiation within the bone marrow to their maturation and ultimate clearance, with a focus on granulocyte apoptosis and macrophage efferocytosis. We further aim to discuss current and emerging models of inflammation and suggest novel ways of terminating or resolving deleterious inflammatory responses with a specific view to the translation of these strategies into fully realized, pro-resolution therapies.

Cell death in the neighbourhood: direct microenvironmental effects of apoptosis in normal and neoplastic tissues

Here we consider the impact of the physiological cell-death programme on normal tissue homeostasis and on disease pathogenesis, with particular reference to evolution and progression of neoplasia. We seek to describe the direct contributions played by apoptosis in creating the microenvironments of normal and malignant tissues and to discuss the molecular mechanisms underlying the elements of the '3Rs' that define the meaning of apoptosis: recognition, response, and removal. Apoptotic cells elicit responses in other cell types-both phagocytic and non-phagocytic-through short- and long-range signalling modes that range from direct contact to intercellular communication via membrane-bound microparticles. Such cellular responses include migration, proliferation, and differentiation, as well as production of immunomodulatory and anti-inflammatory mediators together with, in the case of phagocytes, engulfment, and breakdown of apoptotic cells. In normal tissues, the removal of apoptotic cells is rapid and typically non-phlogistic. We discuss the importance of this clearance process in tissue homeostasis and the consequences of its failure in disease pathogenesis. Using the typical cell culture environment in vitro as an illustrative example in which apoptosis occurs commonly in the absence of the removal mechanisms, we also discuss the inhibitory effects of persistent apoptotic cells on their otherwise viable neighbours. Since apoptosis is a common and sustained event in high-grade malignancies, we hypothesize on its purposeful role in conditioning the tumour microenvironment. We propose that apoptosis subserves several pro-tumour functions-trophic, anti-inflammatory, and immunomodulatory-and we identify strategies targeting host responses to apoptotic cells as promising modes of future therapies that could be applied to multiple cancer types in which tumour-cell apoptosis is active.

Beneficial effects of chelidonic acid on a model of allergic rhinitis

Chelidonic acid (CA) is known as an inhibitor of the rat brain glutamate decarboxylase. However, the pharmacological effects of CA in allergic reactions have not yet been defined. Here, we show the effects and the mechanism of CA in the ovalbumin (OVA)-sensitized allergic rhinitis (AR) model. CA significantly decreased the number of nasal/ear rubs and increment of IgE levels in the AR mice. The level of interferon-γ was enhanced while the level of IL-4 was reduced on the spleen tissue of the CA-administered AR mice. Expressions of IL-1β and cyclooxygenase-2 were inhibited by CA administration in the nasal mucosa tissues. Infiltration of eosinophils and mast cells was decreased in the CA-administered AR mice. Furthermore, CA decreased the caspase-1 activity in the same nasal mucosa tissue and human mast cell line, HMC-1. Our results indicate that CA may attenuate allergic reaction by inhibition of caspase-1 activity.

Human lactoferrin stimulates skin keratinocyte function and wound re-epithelialization

BACKGROUND

Human lactoferrin (hLF), a member of the transferrin family, is known for its antimicrobial and anti-inflammatory effects. Recent studies on various nonskin cell lines indicate that hLF may have a stimulatory effect on cell proliferation.

OBJECTIVES

To study the potential role of hLF in wound re-epithelialization.

MATERIALS AND METHODS

The effects of hLF on cell growth, migration, attachment and survival were assessed, with a rice-derived recombinant hLF (holo-rhLF), using proliferation analysis, scratch migration assay, calcein-AM/propidium iodide staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) method, respectively. The mechanisms of hLF on cell proliferation and migration were explored using specific pathway inhibitors. The involvement of lactoferrin receptor low-density lipoprotein receptor-related protein 1 (LRP1) was examined with RNA interference technique. An in vivo swine second-degree burn wound model was also used to assess wound re-epithelialization.

RESULTS

Studies revealed that holo-rhLF significantly stimulated keratinocyte proliferation which could be blocked by mitogen-activated protein kinase (MAPK) kinase 1 inhibitor. Holo-rhLF also showed strong promoting effects on keratinocyte migration, which could be blocked by either inhibition of the MAPK, Src and Rho/ROCK pathways, or downregulation of the LRP1 receptor. With cells under starving or 12-O-tetradecanoylphorbol-13-acetate exposure, the addition of holo-rhLF was found greatly to increase cell viability and inhibit cell apoptosis. Additionally, holo-rhLF significantly increased the rate of wound re-epithelialization in swine second-degree burn wounds.

CONCLUSIONS

Our studies demonstrate the direct effects of holo-rhLF on wound re-epithelialization including the enhancement of keratinocyte proliferation and migration as well as the protection of cells from apoptosis. The data strongly indicate its potential therapeutic applications in wound healing.

A critical review of the roles of host lactoferrin in immunity

Lactoferrin (Lf) is an essential element of innate immunity, which refers to antigen-nonspecific defense mechanisms that a host uses immediately or within hours after exposure to an antigen. Following infection, Lf is released from neutrophils (PMNs) in blood and inflamed tissues and, such as other soluble pattern-recognition receptors of the innate immunity, Lf recognizes unique microbial molecules called pathogen-associated molecular patterns (PAMPs): LPS from the gram-negative cell wall and bacterial unmethylated CpG DNA. However, unlike classical PAMPs receptors involved in the activation of immune cells, Lf may act either as a competitor for these receptors or as a partner molecule, depending on the physiological status of the organism. These immunomodulatory properties are explained by the ability of Lf to interact with proteoglycans and receptors on the surface of mammalian cells: cells of the innate (NK cells, neutrophils, macrophages, basophils, neutrophils and mast cells) and adaptive [lymphocytes and antigen-presenting cells (APCs)] immune systems, and also epithelial and endothelial cells. Through these interactions, Lf is able to modulate the migration, maturation and functions of immune cells, and thus to influence both adaptive and innate immunities. The understanding of the roles of the host-expressed Lf in immunity comes from in vivo and in vitro studies with exogenous Lf which, although informative, rarely reflect the pathological, or non-pathological, conditions in the organism. In this review, the data from the literature will be critically analyzed in order to present a real picture of the regulatory roles of host Lf in immunity.