IL-4 stimulates the expression of CXCL-8, E-selectin, VEGF, and inducible nitric oxide synthase mRNA by equine pulmonary artery endothelial cells

Impact of dual neutralization of TNF-α and IL-1β along with Gentamicin treatment on the functions of blood and splenic neutrophils and its role on improvement of S. aureus induced septic arthritis

Researches of recent past years have emphasized potential of antibiotics to improve septic arthritis but as multi-drug resistant strains like MRSA are emerging fast, new alternative therapeutic advances are high in demand. This study aims to figure out the role of neutrophils in regulating inflammatory responses of S. aureus induced septic arthritis while using TNF-α Ab or IL-1β Ab along with antibiotic gentamicin or both in combination. In this study, role of anti-oxidant enzymes were investigated and correlated with generated ROS level. While expression of TLR2, TNFR2, MMP2, RANKL, SAPK/JNK in the spleen were evaluated through western blot. Serum activity of IL-8, IL-10, IL-12, OPG, OPN, CRP was assessed using ELISA. Flow cytometry study evaluated inflamed neutrophil population. Results have shown TNF-α neutralization along with gentamicin was able to reduce arthritic swelling prominently. While combination therapy effectively reduced blood neutrophil ROS activity, arginase activity, MPO activity along with spleen bacterial burden. Serum OPG, CRP, IL-10 level got reduced while serum OPN, IL-8 and IL-12 level enhanced in treatment groups, showing mitigation of inflammatory damage. Overall, it is a novel work that observed how antibiotic and antibody therapy enhanced neutrophil function positively to combat sepsis. This study may not be fully applicable in clinical trials as it is performed with animal model. Clinical trials include crystalline and inflammatory arthritides, trauma, neoplasm. Interdisciplinary collaboration between radiology, orthopaedic surgery and knowledge of animal system responses may give better idea to find proper therapeutic approach in future research works.

IL-4-loaded alginate/chitosan multilayer films for promoting angiogenesis through both direct and indirect means

Vascularization remains a major challenge in tissue engineering. In tissue repair with the involvement of biomaterials, both the material properties and material-induced immune response can affect angiogenesis. However, there is a scarcity of research on biomaterials that modulate angiogenesis simultaneously from both perspectives. Meanwhile, the effects and mechanisms of biomaterial-induced macrophages on angiogenesis remain controversial. In this study, a cytokine-controlled release system from our previous work was employed, and the effects thereof on angiogenesis through both direct and indirect means were investigated. Alginate/chitosan multilayer films were fabricated on interleukin (IL)-4-loaded titania nanotubes to achieve a sustained release of IL-4. The released IL-4 and the multilayers synergistically promoted angiogenic behaviors of endothelial cells (ECs), while up-regulating the expression of early vascular markers. Furthermore, polarized macrophages (both M1 and M2) notably elevated the expression of late vascular markers in ECs via the high expression of pro-maturation factor angiogenin-1. After subcutaneous implantation, the IL-4-loaded implants induced increased neovascularization in a short period, with the surrounding tissue returning to normal at the later stage. Therefore, the proposed IL-4-loaded implants exhibited superior pro-angiogenic capability in vitro and in vivo through both direct stimulation of ECs and the indirect induction of a suitable immune microenvironment.

Glucocorticoid treatment in horses with asthma: A narrative review

Despite substantial research efforts to improve the treatment and outcome of horses with asthma, glucocorticoids (GC) remain the cornerstone of drug treatment of this prevalent disease. The high efficacy of GC to relieve airway obstruction explains their extensive use despite potential deleterious effects. However, much is yet to be uncovered concerning GC use in horses with asthma, including the comparative efficacy of the different drugs, the determination of minimal effective doses and the mechanisms underlying their variable modulation of airway inflammation. The objectives of this structured review were to report and compare the plethora of effects of the various GC used in asthmatic horses with a focus on impact on lung function, airway inflammation, and bronchial remodeling. Adverse effects are also briefly described, with an emphasis on those that have been specifically reported in horses with asthma. Ultimately, we aimed to highlight gaps in the literature and to identify future research areas.

Bronchial angiogenesis in horses with severe asthma and its response to corticosteroids

Background

Severe asthma in horses is characterized by structural changes that thicken the lower airway wall, a change that is only partially reversible by current treatments. Increased vascularization contributes to the thickening of the bronchial wall in humans with asthma and is considered a potential new therapeutic target.

Objective

To determine the presence of angiogenesis in the bronchi of severely asthmatic horses, and if present, to evaluate its reversibility by treatment with corticosteroids.

Animals

Study 1: Bronchial samples from asthmatic horses in exacerbation (7), in remission (7), and aged‐matched healthy horses. Study 2: Endobronchial biopsy samples from asthmatic horses in exacerbation (6) and healthy horses (6) before and after treatment with dexamethasone.

Methods

Blinded, randomized controlled study. Immunohistochemistry was performed using collagen IV as a marker for vascular basement membranes. Number of vessels, vascular area, and mean vessel size in the bronchial lamina propria were measured by histomorphometry. Reversibility of vascular changes in Study 2 was assessed after 2 weeks of treatment with dexamethasone.

Results

The number of vessels and vascular area were increased in the airway walls of asthmatic horses in exacerbation (P = .01 and P = .02, respectively) and in remission (P = .02 and P = .04, respectively) when compared to controls. In Study 2, the differences observed between groups disappeared after 2 weeks of treatment with corticosteroids because of the increased number of vessels in healthy horses.

Conclusions and Clinical Importance

Angiogenesis contributes to thickening of the airway wall in asthmatic horses and was not reversed by a 2‐week treatment with corticosteroids.

Cytokines and Exhaled Nitric Oxide Are Risk Factors in Preterm Infants for Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common complication of extremely preterm birth. This study was aimed at detecting cytokine and fractional exhaled nitric oxide (FeNO) levels to evaluate their mechanisms and predicted significance for BPD. Preterm infants born at gestational age ≤ 32 weeks were recruited, and clinical data were collected. We detected ten cytokines, including IFN-γ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8, and TNF-α on Days 1–3, Days 7–14, and Days 21–28 after birth by using the Meso Scale Discovery (MSD) technology. The FeNO levels of infants were measured when they met the discharge criteria. A total of 46 preterm infants were enrolled, consisting of 14 infants in BPD group and 32 infants in the control group. The gestational age (27.5 ± 1.3 vs. 29.9 ± 1.3 weeks) and birth weight (1021 ± 261 g vs. 1489 ± 357 g) were lower in the BPD group. The following were high-risk factors for BPD, as determined by multivariate logistic regression analysis: gestational age < 30 weeks, birth weight < 1000 g, PDA, longer mechanical ventilation, and higher FeNO. The cytokines of IL-6 and IL-8 on Days 7–14 and IL-4, IL-6, IL-8, and TNF-α on Days 21–28 were also high-risk factors for BPD. IL-6 contributed to BPD disease severity. Conclusion. The preterm infants with PDA and prolonged mechanical ventilation tended to develop BPD. The IL-6 and IL-8 were significantly increased on Days 7–14 and were high-risk factors for BPD. Moreover, the IL-6 level was associated with BPD disease severity. We speculated that NO was related to BPD via Th2 cell-mediated inflammatory responses such as IL-4 and IL-6. Cytokines might predict the occurrence of BPD.

Endothelial cells and angiogenesis in the horse in health and disease-A review

The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.

Use of a biopolymer delivery system to investigate the influence of interleukin-4 on recruitment of neutrophils in equids

OBJECTIVE

To use a biopolymer delivery system to investigate the ability of interleukin (IL)-4 to recruit neutrophils into subcutaneous tissues of equids.

ANIMALS

16 horses and 2 ponies.

PROCEDURES

Animals were assigned to 3 experiments (6/experiment). Effects of recombinant equine (Req) IL-4 (100, 250, or 500 ng/site) versus a positive control (ReqIL-8; 100 ng, 250 ng, or 1 μg/site) and a negative control (Dulbecco PBSS or culture medium) on neutrophil chemotaxis were assessed after SC injection into the neck with an injectable biopolymer used as the vehicle. Tissue samples including the biopolymer plug were collected by biopsy at various time points from 3 hours to 7 days after injection. Neutrophil infiltration was evaluated by histologic scoring (experiments 1, 2, and 3) or flow cytometry (experiment 3).

RESULTS

Histologic neutrophil infiltration scores did not differ significantly among treatments at most evaluated time points. On flow cytometric analysis, log-transformed neutrophil counts in biopsy specimens were significantly greater for the ReqIL-8 treatment (1 μg/site) than the negative control treatment at 3 but not 6 hours after injection; results did not differ between ReqIL-4 and control treatments at either time point. Negative control treatments induced an inflammatory response in most equids in all experiments.

CONCLUSIONS AND CLINICAL RELEVANCE

Flow cytometry was a more reliable method to estimate neutrophil migration than histologic score analysis. The ReqIL-4 treatment did not induce a detectable neutrophil response, compared with the negative control treatment in this study. Evidence of inflammation in negative control samples suggested the biopolymer is not a suitable vehicle for use in equids.

Fractional Exhaled Nitric Oxide (FENO) in the management of asthma: a position paper of the Italian Respiratory Society (SIP/IRS) and Italian Society of Allergy, Asthma and Clinical Immunology (SIAAIC)

Asthma prevalence in Italy is on the rise and is estimated to be over 6% of the general population. The diagnosis of asthma can be challenging and elusive, especially in children and the last two decades has brought evidences that asthma is not a single disease but consists of various phenotypes. Symptoms can be underestimated by the patient or underreported to the clinician and physical signs can be scanty. Usual objective measures, like spirometry, are necessary but sometimes not significant. Despite proper treatment, asthma can be a very severe condition (even leading to death), however new drugs have recently become available which can be very effective in its control. Since asthma is currently thought to be caused by inflammation, a direct measure of the latter can be of paramount importance. For this purpose, the measurement of Fractional Exhaled Nitric Oxide (FE_NO) has been used since the early years of the current century as a non-invasive, easy-to-assess tool useful for diagnosing and managing asthma. This SIP-IRS/SIAAIC Position Paper is a narrative review which summarizes the evidence behind the usefulness of FE_NO in the diagnosis, management and phenotypization of asthma.

Immunomodulatory asthma therapy in the equine animal model: A dose-response study and evaluation of a long-term effect

INTRODUCTION

Equine asthma represents a naturally occurring animal model for human allergic neutrophilic asthma. Inhalative nanoparticle-bound cytosine-phosphate-guanosine (CpG-GNP) immunotherapy, independent of specific allergens, has already shown promising clinical and immunological results in previous studies and offers the possibility to treat the underlying cause of the disease. This study analyses the relationship between dose and response, and evaluates a possible long-term effect.

METHODS

In the prospective, randomised, double-blind clinical field study, 29 horses suffering from equine asthma received 10 inhalation treatments with either 187.5 µg CpG-GNP (CpG single dose [CpGsd]; n = 11), 375 µg CpG-GNP double dose (CpG double dose [CpGdd]; n = 9) (q48h for 20 days) or 1600 µg beclomethasone (n = 9) (q24h for 10 days). Each horse was examined three times: before the treatment (I), immediately after the 10 inhalations (II), and 8 weeks after the final inhalation (III). The three groups were compared according to clinical and laboratory parameters. The study examined the sustainability of the long-term effect of the treatment after 8 weeks, as well as the tolerability of the formula as a double dose.

RESULTS

The CpGsd resulted in a significant improvement in 82% of the parameters, the CpGdd in 72%. In the long-term evaluation, the CpGsd showed a significant improvement in 100% of the parameters in comparison to the initial values, the CpGdd in 67%. On the immunological level, the bronchoalveolar lavage revealed a significant reduction of IL-4, IL-8, and interferon-γ.

CONCLUSION

Both CpG groups displayed significant improvements in clinical and laboratory parameters, especially regarding the long-term effect of CpGsd. Doubling the CpG dose did not result in any improvement in comparison to the original single dose. On the immunological level, an anti-inflammatory, as well as an immunomodulatory effect, apart from a Th2-dominated immune response, could be observed. This immunomodulatory inhalation treatment could indicate a new possibility for human allergic asthma therapy.

The associations between serum vascular endothelial growth factor, tumor necrosis factor and interleukin 4 with the markers of blood-brain barrier breakdown in patients with paraneoplastic neurological syndromes

The blood–brain barrier (BBB) disruption is a critical step in paraneoplastic neurological syndrome (PNS) development. Several cytokines have been implicated in BBB breakdown. However, the exact step-by-step mechanism in which PNS develops is unknown, and the relationship between a systemic neoplasm and BBB is multilevel. The aim of the present study was to examine serum markers of BBB breakdown (S100B protein, neuron-specific enolase, NSE) and concentrations of proinflammatory (TNF-alpha, VEGF) and anti-inflammatory/immunosuppressive cytokines (IL-4), and to establish their interrelationship in patients with PNS. We analyzed 84 patients seropositive for onconeural antibodies that originated from a cohort of 250 cases with suspected PNS. Onconeural antibodies were estimated with indirect immunofluorescence and confirmed with Western blotting. Serum S-100B was estimated using electrochemiluminescence immunoassay. NSE, VEGF, TNF-alpha and IL-4 were analyzed with ELISA. We found that S-100B protein and NSE serum concentrations were elevated in PNS patients without diagnosed malignancy, and S-100B additionally in patients with peripheral nervous system manifestation of PNS. Serum VEGF levels showed several abnormalities, including a decrease in anti-Hu positive patients and increase in PNS patients with typical manifestation and/or central nervous system involvement. Increase in TNF-alpha was observed in patients with undetermined antibodies. To conclude, the presence of paraneoplastic neurological syndrome in seropositive patients does not affect serum markers of BBB breakdown, with the exception of the group without clinically demonstrated malignancy and patients with peripheral manifestation of PNS. S-100B and NSE might increase during early phase of PNS. VEGF may be involved in typical PNS pathophysiology.

Effect of Cytokines on the Formation Tube-Like Structures by Endothelial Cells in the Presence of Trophoblast Cells

Despite ample data on cytokine secretion in the uteroplacental interface, the influence of microenvironment cells, in particular, trophoblast cells on angiogenesis and the role of cytokines in this process remain poorly studied. We studied the influence of cytokines on the formation of tube-like structures by endothelial cells in the presence of trophoblast cells and showed that trophoblast cells suppressed the angiogenic potential of endothelial cells. Antiangiogenic cytokines IFN-γ, IL-10, TNF-α, and TGFβ via modulation of trophoblast cells stimulated the formation of tube-like structures by endothelial cells. In the co-culture of endothelial and trophoblast cells, the effects of cytokines changed and they gained additional regulatory functions.

Identification and Expression Analysis of Zebrafish (Danio rerio) E-Selectin during Embryonic Development

In this study, we cloned the full-length cDNA of E-selectin of zebrafish (Danio rerio), analyzed its expression pattern and preliminarily explored its biological function. Zebrafish E-selectin cDNA is 3146 bp and encodes a putative 871 amino acid protein. All structural domains involved in E-selectin function are conserved in the putative protein. Whole-mount in situ hybridization of zebrafish at 24 and 48 h post-fertilization (hpf) revealed E-selectin expression mainly in vascular/endothelial progenitor cells in the posterior trunk and blood cells in the intermediate cell mass and posterior cardinal vein regions. Real-time quantitative RT-PCR analysis detected E-selectin expression at 0.2, 24 and 48 hpf and significantly decreased from 48 to 72 hpf. The expression of E-selectin, tumor necrosis factor-α and interleukin-1β was significantly upregulated at 22 to 72 h after induction with bacterial lipopolysaccharide. Thus, the structure of E-selectin protein is highly conserved among species, and E-selectin may be involved in embryonic development and essential for hematopoiesis and angiogenesis during embryonic development in zebrafish. Furthermore, we provide the first evidence of inflammatory mediators inducing E-selectin expression in non-mammalian vertebrates, which suggests that zebrafish E-selectin may be involved in inflammation and probably has similar biological function to mammalian E-selectin.

The expression of vascular endothelial growth factor in pterygium tissue of atopic patients

The exact pathogenesis of pterygium has not been completely elucidated. Growth factors have been considered to play a role in pterygium formation. Vascular endothelial growth factor (VEGF) is one of the principal mediators of angiogenesis, fibroblast stimulation and tissue remodeling in allergic conditions. The aim of this study was to compare the association between pterygium and VEGF gene expression between atopic and non-atopic individuals. At first visit, all patients with pterygium underwent blood tests, serum immunoglobulin E (IgE), serum cytokines including interleukin-4 (IL-4) and interferon-γ (IFN-γ) and peripheral blood eosinophil count. After obtaining informed consents, questionnaires were used to obtain demographic and clinical data from patients who underwent pterygium excision surgery. Skin prick test was performed to confirm or rule out atopy in 30 patients with (case group) and 30 patients without (control group) atopy. Pterygium tissues were then removed by surgery. A semi-quantitative reverse transcriptase polymerase chain reaction was performed to determine VEGF gene expression in all patients. Our results illustrated that VEGF mRNA expression in atopic patients was significantly higher than in the non-atopic group (P = 0.01). Eosinophil count, serum IgE and IL-4 were also significantly higher in atopic patients than in the non-atopic group (P = 0.03, 0.001 and 0.001, respectively). However, no significant difference was noted in serum IFN-γ between the two groups (P = 0.06). The excessive expression of VEGF gene in pterygium tissue of patients with atopy suggests that growth factors may play a role in the pathogenesis of pterygium or accelerate its formation.

Nitric oxide in cancer metastasis

Cancer metastasis is the spread and growth of tumor cells from the original neoplasm to further organs. This review analyzes the role of nitric oxide (NO), a signaling molecule, in the regulation of cancer formation, progression, and metastasis. The action of NO on cancer relies on multiple factors including cell type, metastasis stage, and organs involved. Various chemotherapy drugs cause cells to release NO, which in turn induces cytotoxic death of breast, liver, and skin tumors. However, NO has also been clinically connected to a poor cancer prognosis because of its role in angiogenesis and intravasation. This supports the claim that NO can be characterized as both pro-metastatic and anti-metastatic, depending on specific factors. The inhibition of cell proliferation and anti-apoptosis pathways by NO donors has been proposed as a novel therapy to various cancers. Studies suggest that NO-releasing non-steroidal anti-inflammatory drugs act on cancer cells in several ways that may make them ideal for cancer therapy. This review summarizes the biological significance of NO in each step of cancer metastasis, its controversial effects for cancer progression, and its therapeutic potential.

iNOS expression and NO production contribute to the direct effects of BCG on urothelial carcinoma cell biology

OBJECTIVES

Evidence suggests that oxidative stress occurring as a consequence of inducible nitric oxide synthase/nitric oxide (iNOS/NO) contributes to the biologic effects of bacille Calmette-Guérin (BCG). Objective of this study is to examine iNOS expression, NO production, and the biologic effect of NO on established intermediate end points for the human urothelial carcinoma cell response to BCG.

MATERIALS AND METHODS

Quantitative reverse transcriptase-polymerase chain reaction and real-time measurement of NO was used to assess iNOS and NO production, respectively, in 2 human urothelial carcinoma (UC) cell lines, in response to BCG. The effect of blocking NO production using the specific iNOS inhibitor 1400W was determined for multiple intermediate end points characterizing BCG's direct effects on tumor cell biology. Activation of nuclear factor kappa B and nuclear factor (erythroid-derived 2)-like 2 signaling pathways, transactivation of genes, including p21, CD54, IL6, IL8, CXCL1, CXCL3, CCL20, and cytotoxicity, as measured by vital dye exclusion, lactate dehydrogenase release, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were measured in response to BCG with and without iNOS inhibition.

RESULTS

Exposure of UC cells to BCG significantly increased both iNOS expression and NO production. Inhibition of iNOS activity with 1400W significantly inhibited BCG's direct biologic effect on UC cells for all of the end points evaluated.

CONCLUSIONS

iNOS expression, NO production, and the associated oxidative stress play a central role in the response of UC cells to BCG exposure. Manipulation of oxidative stress may afford an opportunity to enhance the antitumor effects of BCG.

Interleukin (IL)-4 induces production of cytokine-induced neutrophil chemoattractants (CINCs) and intercellular adhesion molecule (ICAM)-1 in lungs of asthmatic rats

The present study aimed to examine the effect of interleukin (IL)-4 on neutrophil chemotaxis in airway inflammation in asthmatic rats and the possible mechanism. Male Wistar rats were intranasally instilled with recombinant rat (rr) IL-4 (rrIL-4) at different doses [2, 4 or 8 μg/animal, dissolved in 200 μL normal saline (NS)] or rrIL-4 at 4 μg/animal (dissolved in 200 μL NS). NS (200 μL) and LPS (6 mg/kg/animal, dissolved in 200 μL NS) were intranasally given respectively in the negative and positive control groups. Moreover, the asthmatic lung inflammation was induced in rats which were then intranasally treated with rrIL-4 (4 μg/animal) or LPS (6 mg/kg/animal). The normal rats treated with different doses of rrIL-4 and those asthmatic rats were sacrificed 6 h later. And animals instilled with rrIL-4 at 4 μg were sacrificed 6, 12 or 24 h later. The bronchoalveolar lavage fluid (BALF) and lungs were harvested for detection of leukocyte counts by Wright-Giemsa staining and lung histopathology by haematoxylin-eosin (HE) staining. The levels of cytokine-induced neutrophil chemoattractant (CINC)-1 and intercellular adhesion molecule (ICAM)-1 in BALF were determined by ELISA. Real-time PCR was used to measure the mRNA expression of CINCs (CINC-1, CINC-2α, CINC-2β, CINC-3) and ICAM-1 in lung tissues. The results showed that the intranasal instillation of IL-4 did not induce a recruitment of neutrophils in BALF in rats. However, IL-4 could increase the CINC-1 level in BALF in a dose-dependent manner at 6 h. But the mRNA expression levels of CINC-1, CINC-2α, CINC-2β, CINC-3 were not significantly increased in lungs of IL-4-treated rats relative to NS negative control group. Moreover, IL-4 was found to augment the mRNA expression of ICAM-1 in lungs and the ICAM-1 level in BALF at 6 h. However, the increase in CINC-1 and ICAM-1 levels in BALF of IL-4-treated asthmatic rats was not significantly different from that in untreated asthmatic rats. These findings indicate that IL-4 does not directly recruit neutrophils in the rat lungs, but it may contribute to airway neutrophilia through up-regulation of CINC-1 and ICAM-1.

The immunopathology of sepsis: pathogen recognition, systemic inflammation, the compensatory anti-inflammatory response, and regulatory T cells

Sepsis, the systemic inflammatory response to infection, represents the major cause of death in critically ill veterinary patients. Whereas important advances in our understanding of the pathophysiology of this syndrome have been made, much remains to be elucidated. There is general agreement on the key interaction between pathogen-associated molecular patterns and cells of the innate immune system, and the amplification of the host response generated by pro-inflammatory cytokines. More recently, the concept of immunoparalysis in sepsis has also been advanced, together with an increasing recognition of the interplay between regulatory T cells and the innate immune response. However, the heterogeneous nature of this syndrome and the difficulty of modeling it in vitro or in vivo has both frustrated the advancement of new therapies and emphasized the continuing importance of patient-based clinical research in this area of human and veterinary medicine.

Heaves, an asthma-like disease of horses

Animal models have been developed to investigate specific components of asthmatic airway inflammation, hyper-responsiveness or remodelling. However, all of these aspects are rarely observed in the same animal. Heaves is a naturally occurring disease of horses that combines these features. It is characterized by stable dust-induced inflammation, bronchospasm and remodelling. The evaluation of horses during well-controlled natural antigen exposure and avoidance in experimental settings allows the study of disease mechanisms in the asymptomatic and symptomatic stages, an approach rarely feasible in humans. Also, the disease can be followed over several years to observe the cumulative effect of repeated episodes of clinical exacerbation or to evaluate long-term treatment, contrasting most murine asthma models. This model has shown complex gene and environment interactions, the involvement of both innate and adaptive responses to inflammation, and the contribution of bronchospasm and tissue remodelling to airway obstruction, all occurring in a natural setting. Similarities with the human asthmatic airways are well described and the model is currently being used to evaluate airway remodelling and its reversibility in ways that are not possible in people for ethical reasons. Tools including antibodies, recombinant proteins or gene arrays, as well as methods for sampling tissues and assessing lung function in the horse are constantly evolving to facilitate the study of this animal model. Research perspectives that can be relevant to asthma include the role of neutrophils in airway inflammation and their response to corticosteroids, systemic response to pulmonary inflammation, and maintaining athletic capacities with early intervention.

Role of IL-4 in an experimental model of encephalitis induced by intracranial inoculation of herpes simplex virus-1 (HSV-1)

Herpes simplex virus-1 (HSV-1) is a pathogen that may cause severe encephalitis in humans. In this study, we aimed to investigate the role of interleukin-4 (IL-4) in a model of HSV-1 brain infection. IL-4 knockout (IL-4-/-) and wild type (WT) C57BL/6 mice were inoculated with 10(4) plaque-forming units of HSV-1 by the intracranial route. Histopathologic analysis revealed a distinct profile of infiltrating cells at 3 days post-infection (dpi). Infected WT mice presented mononuclear inflammatory cells while IL-4-/- mice developed meningoencephalitis with predominance of neutrophils. IL-4-/- mice had diminished leukocyte adhesion at 3 dpi when compared to infected WT animals in intravital microscopy study. Conversely no differences were found in cerebral levels of CXCL1, CXCL9, CCL3, CCL5 and TNF-α between WT and IL-4-/- infected mice. IL-4 may play a role in the recruitment of cells into central nervous system in this acute model of severe encephalitis caused by HSV-1.

Interleukin(IL)-4 promotion of CXCL-8 gene transcription is mediated by ERK1/2 pathway in human pulmonary artery endothelial cells

Interleukin-4 is central to allergic pulmonary inflammatory responses, but its contribution to airway neutrophilia remains controversial. The endothelium plays a critical role in regulating leukocyte recruitment and migration during inflammation. However, its response to IL-4 is reported to either increase or decrease the production of neutrophil chemotactic factors. We hypothesized that these conflicting findings may be due to the tissue and the size of the vessels from which endothelial cells have been derived. The expression of CXCL-8 by human primary culture umbilical veins endothelial cells (HUVECs), human pulmonary artery endothelial cells (HPAECs), and human pulmonary microvascular endothelial cells (HPMECs) when stimulated with recombinant human IL-4 (rhIL-4) was studied. The chemoattractant property of the cells' supernatants for neutrophils was evaluated using Boyden chambers. The role of the nuclear factor-κB (NF-κB), and mitogen-activated protein kinases (MAPK) in IL-4-induced HPAECs was studied using Western blotting and electrophoretic mobility shift assay (EMSA). We demonstrated that IL-4 increased the mRNA expression and the protein production of CXCL-8 in HPAECs, but not in HUVECs and HPMECs. The supernatants of HAPECs stimulated by IL-4 significantly promoted neutrophils migration in a dose-dependent manner, and was significantly attenuated by an inhibitor of CXCL-8. We also found that extracellular-regulated protein kinase1/2 (ERK1/2) is activated by IL-4 in HPAECs, but not JUN-N-terminal protein kinase (JNK) or p38 MAPK pathway. Furthermore, NF-κB-DNA binding activity, phosphorylation of IκBα and p65 levels were not affected by rhIL-4 in HAPECs. These findings indicate marked functional differences in the response of micro and macro-ECs to IL-4. ERK1/2, rather than NF-κB, JNK and p38 MAPK signaling, plays a role in IL-4 induced chemokine activation. Our results suggest that inhibition of ERK1/2 may be a possible target for airway neutrophilia in allergic lung diseases.

Alternative activation of macrophages by IL-4 requires SHIP degradation

Alternatively activated macrophages are critical in host defense against parasites and are protective in inflammatory bowel disease, but contribute to pathology in asthma and solid tumors. The mechanisms underlying alternative activation of macrophages are only partially understood and little is known about their amenability to manipulation in pathophysiological conditions. Herein, we demonstrate that Src homology 2-domain-containing inositol-5'-phosphatase (SHIP)-deficient murine macrophages are more sensitive to IL-4-mediated skewing to an alternatively activated phenotype. Moreover, SHIP levels are decreased in macrophages treated with IL-4 and in murine GM-CSF-derived and tumor-associated macrophages. Loss of SHIP and induction of alternatively activated macrophage markers, Ym1 and arginase I (argI), were dependent on phosphatidylinositol 3-kinase (PI3K) activity and argI induction was dependent on the class IA PI3Kp110δ isoform. STAT6 was required to reduce SHIP protein levels, but reduced SHIP levels did not increase STAT6 phosphorylation. STAT6 transcription was inhibited by PI3K inhibitors and enhanced when SHIP was reduced using siRNA. Importantly, reducing SHIP levels enhanced, whereas SHIP overexpression or blocking SHIP degradation reduced, IL-4-induced argI activity. These findings identify SHIP and the PI3K pathway as critical regulators of alternative macrophage activation and SHIP as a target for manipulation in diseases where macrophage phenotype contributes to pathology.

Inhalation of Stachybotrys chartarum evokes pulmonary arterial remodeling in mice, attenuated by Rho-kinase inhibitor

Stachybotrys chartarum, a ubiquitous fungus in our environment, has been suspected of causing respiratory symptoms in humans, such as acute infant pulmonary hemorrhage and asthma. We previously established a mouse model in which repeated inhalation of Stachybotrys chartarum spores caused pulmonary hypertension. To further investigate the model, particularly in the pulmonary circulation, mice were intra-tracheally injected with spores, 18 times over 12 weeks. Severe muscularization was observed in the small- to medium-sized pulmonary arteries. Bronchoalveolar lavage fluid revealed an increase in eosinophils accompanied by high concentrations of Th2-associated cytokines, IL-4, IL-5, but not Th1-associated IFN-γ. The remodeling was temporary, resolving after cessation of spore inhalation. Chronic inhibition of the RhoA/Rho-kinase pathway by fasudil attenuated pulmonary arterial remodeling. These data suggest that Stachybotrys-mediated remodeling is caused by Th2-associated inflammation and can be resolved by Rho-kinase inhibition, either through direct effects on smooth muscle hypertrophy or through indirect effects on vascular inflammation. These data also show that extensive pulmonary vascular remodeling, often thought of as a fixed lesion, will spontaneously resolve in the absence of underlying molecular etiology.

Genome-wide approaches reveal functional interleukin-4-inducible STAT6 binding to the vascular cell adhesion molecule 1 promoter

Endothelial cell activation and dysfunction underlie many vascular disorders, including atherosclerosis and inflammation. Here, we show that interleukin-4 (IL-4) markedly induced vascular cell adhesion molecule 1 (VCAM-1), both in cultured endothelial cells and in the intact endothelium in mice. Combined treatment with IL-4 and tumor necrosis factor alpha (TNF-α) resulted in further, sustained induction of VCAM-1 expression. IL-4-mediated induction of VCAM-1 and secondary monocyte adhesion was predominantly regulated by the transcription factor STAT6. Genome-wide survey of IL-4-mediated STAT6 binding from sequential chromatin-immunoprecipitation with deep sequencing (chromatin immunoprecipitation sequencing [ChIP-seq]) in endothelial cells revealed regions of transient and sustained transcription factor binding. Through the combination of DNA microarrays and ChIP-seq at the same time points, the majority of IL-4-responsive genes were shown to be STAT6 dependent and associated with direct STAT6 binding to their promoter. IL-4-mediated stable binding of STAT6 led to sustained target gene expression. Moreover, our strategy led to the identification of a novel functionally important STAT6 binding site within 16 kb upstream of the VCAM-1 gene. Taken together, these findings support a critical role for STAT6 in mediating IL-4 signal transduction in endothelial cells. Identification of a novel IL-4-mediated VCAM-1 enhancer may provide a foundation for targeted therapy in vascular disease.

Modulation of chicken macrophage effector function by T(H)1/T(H)2 cytokines

Regulation of macrophage activity by T(H)1/2 cytokines is important to maintain the balance of immunity to provide adequate protective immunity while avoiding excessive inflammation. IFN-γ and IL-4 are the hallmark T(H)1 and T(H)2 cytokines, respectively. In avian species, information concerning regulation of macrophage activity by T(H)1/2 cytokines is limited. Here, we investigated the regulatory function of chicken T(H)1 cytokines IFN-γ, IL-18 and T(H)2 cytokines IL-4, IL-10 on the HD11 macrophage cell line. Chicken IFN-γ stimulated nitric oxide (NO) synthesis in HD11 cells and primed the cells to produce significantly greater amounts of NO when exposed to microbial agonists, lipopolysaccharide, lipoteichoic acid, peptidoglycan, CpG-ODN, and poly I:C. In contrast, chicken IL-4 exhibited bi-directional immune regulatory activity: it activated macrophage NO synthesis in the absence of inflammatory agonists, but inhibited NO production by macrophages in response to microbial agonists. Both IFN-γ and IL-4, however, enhanced oxidative burst activity of the HD11 cells when exposed to Salmonella enteritidis. IL-18 and IL-10 did not affect NO production nor oxidative burst in HD11 cells. Phagocytosis and bacterial killing by the HD11 cells were not affected by the treatments of these cytokines. Infection of HD11 cells with S.enteritidis was shown to completely abolish NO production regardless of IFN-γ treatment. This study has demonstrated that IFN-γ and IL-4 are important T(H)1 and T(H)2 cytokines that regulate macrophage function in chickens.

IL-4 activates equine neutrophils and induces a mixed inflammatory cytokine expression profile with enhanced neutrophil chemotactic mediator release ex vivo

Neutrophils are potent contributors to the lung pathophysiological changes occurring in allergic airway inflammation, which typically involve T helper type 2 (Th2) cytokine overexpression. We have previously reported that equine pulmonary endothelial cells are activated by the Th2 cytokine IL-4 and express chemotactic factors for neutrophils after stimulation. We have further explored the possible mechanisms linking Th2-driven inflammation and neutrophilia by studying the effects of recombinant equine IL-4, a prototypical Th2 cytokine, on peripheral blood neutrophils (PBN) isolated from normal animals and from horses with asthmatic airway inflammation (equine heaves). We found that IL-4 induced morphological changes in PBN, dose- and time-dependent expression of IL-8 mRNA, as well as the release of chemotactic factors for neutrophils in culture supernatants. Also, IL-4 induced a mixed inflammatory response in PBN from control and asthmatic-animals with increased expression of proinflammatory IL-8 and TNF-α but a marked inhibition of IL-1β. IL-4 type I receptor (IL-4Rα) and CD23 (FcεRII) expression were also upregulated by IL-4. Importantly, disease as well as chronic antigenic exposure modified gene expression by PBN. Finally, we found that activation of equine neutrophils with IL-4 involved STAT6 phosphorylation and p38 MAPK and phosphatidylinositol 3-kinase (PI3K); the pharmacological inhibitors, SB-203580 and LY-294002, respectively, significantly reversed IL-4-induced gene modulation in PBN. Overall, results from this study add to the link between Th2-driven inflammation and neutrophilia in the equine model and further extend the characterization of IL-4 effects on neutrophils.

Combinatorial effects of interleukin 10 and interleukin 4 determine the progression of hepatic inflammation following murine enteric parasitic infection

Mice lacking the immunoregulatory cytokine interleukin 10 (IL-10) develop necrotizing hepatitis after infection with Trichinella spiralis, and inflammation is dependent on the migration of intestinally activated CD4(+) T cells into the liver. Hepatic production of IL-4 is elevated in these mice, and we hypothesized that it plays a role in the development of hepatic pathology. Wild-type (WT), IL-10 knockout (KO), IL-4 KO, and IL-10/IL-4 KO mice were orally infected, and disease progression was followed by histological examination, alanine aminotransferase assays, and flow cytometric analysis of hepatocellular content. Both IL-10 KO and IL-10/IL-4 KO mice experienced hepatocellular injury, but only IL-10 KO mice advanced to a necrotic phase. Hepatic CD4(+) T cells were the major source of IL-4, and IL-10 regulated the number of intestinally-derived CD4(+)IL-4(+) cells. Sequestration of activated neutrophils in the liver required IL-4, and neutrophil depletion prevented progression to overt necrosis. Adoptive transfer of intestinal WT CD4(+) T cells inhibited neutrophil accumulation and inflammation, but their regulatory effects did not require IL-10 signaling.

CONCLUSION

The absence of IL-10 led to hepatocyte injury during infection, but IL-4 was necessary for the development of neutrophil-dependent necrosis. These studies provide new insight into the combinatorial role of these cytokines and their targets in the generation and progression of hepatic inflammation.

Interleukin-4, Oxidative Stress, Vascular Inflammation and Atherosclerosis

The pro-oxidative and pro-inflammatory pathways in vascular endothelium have been implicated in the initiation and progression of atherosclerosis. In fact, inflammatory responses in vascular endothelium are primarily regulated through oxidative stress-mediated signaling pathways leading to overexpression of pro-inflammatory mediators. Enhanced expression of cytokines, chemokines and adhesion molecules in endothelial cells and their close interactions facilitate recruiting and adhering blood leukocytes to vessel wall, and subsequently stimulate transendothelial migration, which are thought to be critical early pathologic events in atherogenesis. Although interleukin-4 (IL-4) was traditionally considered as an anti-inflammatory cytokine, recent in vitro and in vivo studies have provided robust evidence that IL-4 exerts pro-inflammatory effects on vascular endothelium and may play a critical role in the development of atherosclerosis. The cellular and molecular mechanisms responsible for IL-4-induced atherosclerosis, however, remain largely unknown. The present review focuses on the distinct sources of IL-4-mediated reactive oxygen species (ROS) generation as well as the pivotal role of ROS in IL-4-induced vascular inflammation. These studies will provide novel insights into a clear delineation of the oxidative mechanisms of IL-4-mediated stimulation of vascular inflammation and subsequent development of atherosclerosis. It will also contribute to novel therapeutic approaches for atherosclerosis specifically targeted against pro-oxidative and pro-inflammatory pathways in vascular endothelium.

Role of NADPH oxidase in interleukin-4-induced monocyte chemoattractant protein-1 expression in vascular endothelium

OBJECTIVE AND DESIGN

The pro-oxidative and pro-inflammatory pathways in vascular endothelium have been implicated in the development of atherosclerosis. In the present study, we investigated effect of interleukin-4 (IL-4) on monocyte chemoattractant protein-1 (MCP-1) expression in vascular endothelium and examined the role of distinct sources of reactive oxygen species (ROS) in this process.

METHODS AND RESULTS

Real-time reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay showed that IL-4 significantly up-regulated mRNA and protein expression of MCP-1 in human aortic endothelial cells (HAEC) and C57BL/6 mice. A significant and dose-dependent inhibition of IL-4-induced MCP-1 expression was observed in HAEC pre-treated with antioxidants, such as pyrrolidine dithiocarbamate and epigallocatechin gallate, indicating that IL-4-induced MCP-1 expression is mediated via a ROS-dependent mechanism. Additionally, pharmacological inhibitors of NADPH oxidase (NOX) significantly attenuated IL-4-induced MCP-1 expression in HAEC. Furthermore, the disruption of the NOX gene dramatically reduced IL-4-induced MCP-1 expression in NOX knockout mice (B6.129S6-Cybb(tm1Din)/J). In contrast, overexpression of MCP-1 in IL-4-stimulated HAEC was not affected by inhibiting other ROS generating pathways, such as xanthine oxidase and the mitochondrial electron transport chain.

CONCLUSIONS

These results demonstrate that IL-4 up-regulates MCP-1 expression in vascular endothelium through NOX-mediated ROS generation.

Oxidative mechanisms of IL-4-induced IL-6 expression in vascular endothelium

The present study is designed to investigate the effects of interleukin-4 (IL-4) on expression of interleukin-6 (IL-6), as well as to examine the role of distinct sources of reactive oxygen species (ROS) in this process. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) showed that IL-4 significantly up-regulated the mRNA and protein expression of IL-6 in human aortic endothelial cells (HAEC) and C57BL/6 mice. Dihydroethidium (DHE) and dichlorofluorescein (DCF) fluorescence staining demonstrated that IL-4 significantly increased ROS generation in HAEC. A significant and dose-dependent inhibition of IL-4-induced IL-6 expression was observed in HAEC pre-treated with antioxidants, such as pyrrolidine dithiocarbamate (PDTC) and epigallocatechin gallate (EGCG), indicating that IL-4-induced IL-6 expression is mediated via an ROS-dependent mechanism. Additionally, pharmacological inhibitor of NADPH oxidase (NOX) significantly attenuated IL-4-induced ROS generation and IL-6 expression in HAEC. Furthermore, the disruption of NOX gene dramatically and significantly reduced IL-4-induced IL-6 expression in NOX knockout mice (B6.129S6-Cybb(tm1Din)/J). In contrast, overexpression of IL-6 in IL-4-activated HAEC was not affected by inhibiting other ROS generating pathways, such as xanthine oxidase, arachidonic acid metabolism, and the mitochondrial electron transport chain. These results demonstrate that IL-4 up-regulates IL-6 expression in vascular endothelium through NOX-mediated ROS generation.

Intra-arterial transplantation of adult bone marrow cells restores blood flow and regenerates skeletal muscle in ischemic limbs

OBJECTIVE

Bone marrow cell therapy promotes angiogenesis, but the cellular fate of bone marrow cells (BMCs) in the absence of immunosuppressant interventions is unclear. We created a model of severe hind limb ischemia to address whether BMCs form new blood vessels or differentiate into other tissues.

METHODS AND RESULTS

After ligating the common femoral artery in ApoE knockout mice, we injected either phosphate buffered saline (PBS) or 5 x 10(7) adult unfractionated BMCs obtained from green fluorescent protein-positive mice. Laser Doppler imaging of the ischemic limbs revealed that intra-arterial BMCs significantly increased blood flow recovery in ischemic limbs beginning 21 days after surgery and peaking at 27 days (61.8% +/- 15% vs. 41.9% +/- 13.9%, respectively, for BMCs and PBS, P < .05). The BMCs differentiated into small blood vessels, skeletal myofibers, and supporting membranes, and these changes were associated with increased serum levels of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF-2), transforming growth factor beta (TGFbeta), interleukin 4 (IL-4), and tumor necrosis factor alpha (TNF-alpha).

CONCLUSIONS

Adult BMCs injected into ischemic limbs without immunosuppressant therapy differentiated into blood vessels and skeletal myofibers, and this was associated with accelerated blood flow restoration and increased serum levels of VEGF, FGF-2, TGF-beta, IL-4, and TNF-alpha. Skeletal muscle formation may provide benefits beyond angiogenesis to patients with chronic peripheral arterial disease or to patients with low cardiac output states who also suffer from skeletal muscle atrophy.

Cholinergic stimulation attenuates the IL-4 induced expression of E-selectin and vascular endothelial growth factor by equine pulmonary artery endothelial cells

The endothelium plays a critical role in regulating leukocyte recruitment and migration during inflammation. Recent studies provide evidence that acetylcholine (ACh) and other cholinergic mediators block endothelial cells activation and leukocyte recruitment during inflammation. We thus postulated that the non-neuronal cholinergic system might modulate the recruitment of neutrophils during allergic pulmonary inflammation. In the present study, we examined the effects of cholinergic stimulation on the expression of neutrophil chemokines and adhesion molecules by endothelial cells stimulated by recombinant equine (re) IL-4. Using primary equine pulmonary artery endothelial cells culture and real-time RT-PCR method, we observed that ACh, nicotine, and muscarine inhibit the expression of E-selectin and vascular endothelial growth factor by endothelial cells stimulated by reIL-4. The expression of CXCL-8, a potent neutrophil chemotactic cytokine, remained unaffected however. These findings suggest that the cholinergic anti-inflammatory pathway may modulate pulmonary allergic inflammation and remodeling by the inhibition of selected adhesion molecules and growth factors.