Recombinant IGFBP-3 inhibits allergic lung inflammation, VEGF production, and vascular leak in a mouse model of asthma

The Role of Eosinophil-Derived Neurotoxin and Vascular Endothelial Growth Factor in the Pathogenesis of Eosinophilic Asthma

Asthma is a chronic complex pulmonary disease characterized by airway inflammation, remodeling, and hyperresponsiveness. Vascular endothelial growth factor (VEGF) and eosinophil-derived neurotoxin (EDN) are two significant mediators involved in the pathophysiology of asthma. In asthma, VEGF and EDN levels are elevated and correlate with disease severity and airway hyperresponsiveness. Diversity in VEGF polymorphisms results in the variability of responses to glucocorticosteroids and leukotriene antagonist treatment. Targeting VEGF and eosinophils is a promising therapeutic approach for asthma. We identified lichochalcone A, bevacizumab, azithromycin (AZT), vitamin D, diosmetin, epigallocatechin gallate, IGFBP-3, Neovastat (AE-941), endostatin, PEDF, and melatonin as putative add-on drugs in asthma with anti-VEGF properties. Further studies and clinical trials are needed to evaluate the efficacy of those drugs. AZT reduces the exacerbation rate and may be considered in adults with persistent symptomatic asthma. However, the long-term effects of AZT on community microbial resistance require further investigation. Vitamin D supplementation may enhance corticosteroid responsiveness. Herein, anti-eosinophil drugs are reviewed. Among them are, e.g., anti-IL-5 (mepolizumab, reslizumab, and benralizumab), anti-IL-13 (lebrikizumab and tralokinumab), anti-IL-4 and anti-IL-13 (dupilumab), and anti-IgE (omalizumab) drugs. EDN over peripheral blood eosinophil count is recommended to monitor the asthma control status and to assess the efficacy of anti-IL-5 therapy in asthma.

MicroRNA-205-5p plays a suppressive role in the high-fat diet-induced atrial fibrosis through regulation of the EHMT2/IGFBP3 axis

Objective

MicroRNAs (miRNAs) targeting has been revealed to be an appealing strategy for the treatment and management of atrial fibrillation (AF). In this research, we aimed to explore the mechanisms of miR-205-5p in reducing the high-fat diet (HFD)-induced atrial fibrosis through the EHMT2/IGFBP3 axis.

Methods

Expression levels of miR-205-5p, IGFBP3 and EHMT2 were determined in AF patients, cell fibrosis models and mouse atrial fibrosis models. Luciferase activity and RIP assays were performed to detect the binding between miR-205-5p and EHMT2, and ChIP assays were implemented to detect the enrichment of H3K9me2 and H3K4me3 in the promoter region of IGFBP3 in cells. The related experiments focusing on the inflammatory response, atrial fibrosis, mitochondrial damage, and metabolic abnormalities were performed to figure out the roles of miR-205-5p, IGFBP3, and EHMT2 in cell and mouse atrial fibrosis models.

Results

Low expression levels of miR-205-5p and IGFBP3 and a high expression of EHMT2 were found in AF patients, cell fibrosis models and mouse atrial fibrosis models. Upregulation of miR-205-5p reduced the expression of TGF-β1, α-SMA, Col III and other fibrosis-related proteins. miR-205-5p overexpression targeted EHMT2 to regulate the methylation of H3 histones to promote IGFBP3 expression, which in turn affected the fibrosis of atrial muscle cells. In HFD-induced atrial fibrosis mice, upregulated miR-205-5p or elevated IGFBP3 alleviated atrial fibrosis, mitochondrial damage, and metabolic abnormalities.

Conclusion

This study suggests that miR-205-5p attenuates HFD-induced atrial fibrosis via modulating the EHMT2/IGFBP3 axis.

Graphical Abstract

miR-205-5p alleviates high-fat diet-induced atrial fibrosis in mice via EHMT2/IGFBP3.

Aggravation of pulmonary fibrosis after knocking down the Aryl hydrocarbon receptor in the Insulin-like growth factor 1 receptor pathway

BACKGROUND AND PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a devastating disease with multiple contributing factors. Insulin-like growth factor 1 receptor (IGF1R), with a reciprocal function to Aryl hydrocarbon receptor (AhR), is known to be involved in the development of airway inflammation. However, the exact relationship between IGF1R and AhR in lung fibrogenesis is unclear. This study aimed to investigate the cascade pathway involving IGF1R and AhR in IPF.

EXPERIMENTAL APPROACH

The AhR and IGF1R expressions were determined in the lungs of IPF patients and in a rodent fibrosis model. Pulmonary fibrosis was evaluated in bleomycin (BLM)-induced lung injury in wild type and AhR knockout (AhR^-/- ) mice. The effects of IGF1R inhibition and AhR activation in vitro on TGF-β1-induced epithelial-mesenchymal transition (EMT) in Beas2B cells and in vivo on BLM-exposed mice were also examined.

KEY RESULTS

There were increased IGF1R levels but diminished AhR expression in the lung tissues of IPF patients and BLM-induced mice. Knockout of AhR aggravated lung fibrosis, while the use of IGF1R inhibitor and AhR agonist significantly attenuated such effects and inhibited TGF-β1-induced EMT in Beas2B cells. Both TGF-β1 and BLM markedly suppressed AhR expression through endoplasmic reticulum (ER) stress and consequently, IGF1R activation. The IGF1R inhibitor and specific knockdown of IGF1R reversed the activation of the TGF-β1 signal pathway.

CONCLUSION AND IMPLICATIONS

In the development of IPF, AhR and IGF1R play opposite roles via the TGF-β/Smad/STAT signaling cascade. The AhR/IGF1R axis is a potential target for the treatment of lung injury and fibrosis.

Novel Aspects of Insulin-like Growth Factor 1/insulin Network in Chronic Inflammatory Airway Disease

At least a proportion of patients suffering from chronic inflammatory airway diseases respond poorly to the bronchodilator and corticosteroid therapies. There is a need for the development of improved anti-inflammatory treatment. Insulin Growth Factor 1 (IGF1) and insulin participate in not only metabolism and glucose homeostasis, but also many other physiological and pathophysiological processes, including growth and inflammation. Recently, it was shown that not only the classical IGF1 and IGF1 Receptor (IGF1R), but also the other molecules in the IGF1/insulin network, including insulin, insulin-like growth factor-binding protein (IGFBP), and IGFBP protease, have roles in chronic inflammatory airway diseases. This review aims to provide a comprehensive insight into recent endeavors devoted to the role of the IGF1/insulin network in chronic inflammatory airway diseases. Its participation in airway inflammation, remodeling, and hyper-responsiveness (AHR), as well as acute exacerbation, has been conclusively demonstrated. Its possible relation to glucocorticoid insensitivity has also been indicated. A better understanding of the IGF1/insulin network by further bench-to-bedside research may provide us with rational clinical therapeutic approaches against chronic inflammatory airway diseases.

DM-induced Hypermethylation of IR and IGF1R attenuates mast cell activation and airway responsiveness in rats

Diabetes has been reported to modulate the airway smooth muscle reactivity and lead to attenuation of allergic inflammatory response in the lungs. In this study, we aimed to study the effect of insulin on cell activation and airway responsiveness in patients with diabetes mellitus (DM). The airway contraction in rat model groups including a non‐DM group, a non‐DM+INDUCTION group, a DM+INDUCTION group and a DM+INDUCTION+INSULIN group was measured to observe the effect of insulin on airway responsiveness. Radioenzymatic assay was conducted to measure the levels of histamine, and ELISA assay was conducted to measure bronchial levels of interleukin (IL)‐1b, tumour necrosis factor (TNF)‐a, cytokine‐induced neutrophil chemoattractant (CINC)‐1, P‐selectin and β‐hexosaminidase. The tension in the main and intrapulmonary bronchi of DM+INDUCTION rats was lower than that of the non‐DM+INDUCTION rats, whereas the treatment of insulin partly restored the normal airway responsiveness to OA in DM rats. The release of histamine was remarkably suppressed in DM+INDUCTION rats but was recovered by the insulin treatment. Also, OA significantly increased the levels of IL‐1b, TNF‐a, CINC‐1 and P‐selectin in non‐DM rats, whereas insulin treatment in DM+INDUCTION rats partly restored the normal levels of IL‐1b, TNF‐a, CINC‐1 and P‐selectin in DM rats. Moreover, the expression of IR and IGF1R was evidently suppressed in DM rats, with the methylation of both IR and IGF1R promoters was aggravated in DM rats. Therefore, we demonstrated that DM‐induced hypermethylation inhibited mast cell activation and airway responsiveness, which could be reversed by insulin treatment.

Alzheimer's Disease: Protective Effects of Mycobacterium vaccae, a Soil-Derived Mycobacterium with Anti-Inflammatory and Anti-Tubercular Properties, on the Proteomic Profiles of Plasma and Cerebrospinal Fluid in Rats

BACKGROUND

Alzheimer's disease (AD) is an inflammatory neurodegenerative disease that may be associated with prior bacterial infections. Microbial "old friends" can suppress exaggerated inflammation in response to disease-causing infections or increase clearance of pathogens such as Mycobacterium tuberculosis, which causes tuberculosis (TB). One such "old friend" is Mycobacterium vaccae NCTC 11659, a soil-derived bacterium that has been proposed either as a vaccine for prevention of TB, or as immunotherapy for the treatment of TB when used alongside first line anti-TB drug treatment.

OBJECTIVE

The goal of this study was to use a hypothesis generating approach to explore the effects of M. vaccae on physiological changes in the plasma and cerebrospinal fluid (CSF).

METHODS

Liquid chromatography-tandem mass spectrometry-based proteomics were performed in plasma and CSF of adult male rats after immunization with a heat-killed preparation of M. vaccae NCTC 11659 or borate-buffered saline vehicle. Gene enrichment analysis and analysis of protein-protein interactions were performed to integrate physiological network changes in plasma and CSF. We used RT-qPCR to assess immune and metabolic gene expression changes in the hippocampus.

RESULTS

In both plasma and CSF, immunization with M. vaccae increased proteins associated with immune activation and downregulated proteins corresponding to lipid (including phospholipid and cholesterol) metabolism. Immunization with M. vaccae also increased hippocampal expression of interleukin-4 (IL-4) mRNA, implicating anti-inflammatory effects in the central nervous system.

CONCLUSION

M. vaccae alters host immune activity and lipid metabolism. These data are consistent with the hypothesis that microbe-host interactions may protect against possible infection-induced, inflammation-related cognitive impairments.

ncRNAs in Type-2 Immunity

Immunological diseases, including asthma, autoimmunity and immunodeficiencies, affect a growing percentage of the population with significant unmet medical needs. As we slowly untangle and better appreciate these complex genetic and environment-influenced diseases, new therapeutically targetable pathways are emerging. Non-coding RNA species, which regulate epigenetic, transcriptional and translational responses are critical regulators of immune cell development, differentiation and effector function, and may represent one such new class of therapeutic targets. In this review we focus on type-2 immune responses, orchestrated by T_H2 cell-derived cytokines, IL-4, IL-5 and IL-13, which stimulate a variety of immune and tissue responses- commonly referred to as type-2 immunity. Evolved to protect us from parasitic helminths, type-2 immune responses are observed in individuals with allergic diseases, including Asthma, atopic dermatitis and food allergy. A growing number of studies have identified the involvement of various RNA species, including microRNAs (miRNA) and long non-coding (lncRNA), in type-2 immune responses and in both clinical and pre-clinical disease settings. We highlight these recent findings, identify gaps in our understanding and provide a perspective on how our current understanding can be harnessed for novel treat opportunities to treat type-2 immune-mediated diseases.

Hypoxia enhances CD8+ TC2 cell-dependent airway hyperresponsiveness and inflammation through hypoxia-inducible factor 1α

BACKGROUND

CD8+ type 2 cytotoxic T (TC2) cells undergo transcriptional reprogramming to IL-13 production in the presence of IL-4 to become potent, steroid-insensitive, pathogenic effector cells in asthmatic patients and in mice in a model of experimental asthma. However, no studies have described the effects of hypoxia exposure on TC2 cell differentiation.

OBJECTIVE

We determined the effects of hypoxia exposure on IL-13-producing CD8+ TC2 cells.

METHODS

CD8+ transgenic OT-1 cells differentiated with IL-2 and IL-4 (TC2 cells) were exposed to normoxia (21% oxygen) or hypoxia (3% oxygen), and IL-13 production in vitro was monitored. After differentiation under these conditions, cells were adoptively transferred into CD8-deficient mice, and lung allergic responses, including airway hyperresponsiveness to inhaled methacholine, were assessed. The effects of pharmacologic inhibitors of hypoxia-inducible factor (HIF) 1α and HIF-2α were determined, as were responses in HIF-1α-deficient OT-1 cells.

RESULTS

Under hypoxic conditioning, CD8+ TC2 cell differentiation was significantly enhanced, with increased numbers of IL-13+ T cells and increased production of IL-13 in vitro. Adoptive transfer of TC2 cells differentiated under hypoxic conditioning restored lung allergic responses in sensitized and challenged CD8-deficient recipients to a greater degree than seen in recipients of TC2 cells differentiated under normoxic conditioning. Pharmacologic inhibition of HIF-1α or genetic manipulation to reduce HIF-1α expression reduced the hypoxia-enhanced differentiation of TC2 cells, IL-13 production, and the capacity of transferred cells to restore lung allergic responses in vivo. IL-4-dependent, hypoxia-mediated increases in HIF-1α and TC2 cell differentiation were shown to be mediated through activation of Janus kinase 1/3 and GATA-3.

CONCLUSIONS

Hypoxia enhances CD8+ TC2 cell-dependent airway hyperresponsiveness and inflammation through HIF-1α activation. These findings coupled with the known insensitivity of CD8+ T cells to corticosteroids suggests that activation of the IL-4-HIF-1α-IL-13 axis might play a role in the development of steroid-refractory asthma.

Apolipoprotein E is a concentration-dependent pulmonary danger signal that activates the NLRP3 inflammasome and IL-1β secretion by bronchoalveolar fluid macrophages from asthmatic subjects

BACKGROUND

House dust mite (HDM)-challenged Apoe^-/- mice display enhanced airway hyperreactivity and mucous cell metaplasia.

OBJECTIVE

We sought to characterize the pathways that induce apolipoprotein E (APOE) expression by bronchoalveolar lavage fluid (BALF) macrophages from asthmatic subjects and identify how APOE regulates IL-1β secretion.

METHODS

Macrophages were isolated from asthmatic BALF and derived from THP-1 cells and human monocytes.

RESULTS

HDM-derived cysteine and serine proteases induced APOE secretion from BALF macrophages through protease-activated receptor 2. APOE at concentrations of less than 2.5 nmol/L, which are similar to levels found in epithelial lining fluid from healthy adults, did not induce IL-1β release from BALF macrophages. In contrast, APOE at concentrations of 25 nmol/L or greater induced nucleotide-binding oligomerization domain, leucine-rich repeat-containing protein (NLRP) 3 and pro-IL-1β expression by BALF macrophages, as well as the caspase-1-mediated generation of mature IL-1β secreted from cells. HDM acted synergistically with APOE to both prime and activate the NLRP3 inflammasome. In a murine model of neutrophilic airway inflammation induced by HDM and polyinosinic-polycytidylic acid, APOE reached a concentration of 32 nmol/L in epithelial lining fluid, with associated increases in BALF IL-1β levels. APOE-dependent NLRP3 inflammasome activation in macrophages was primarily mediated through a potassium efflux-dependent mechanism.

CONCLUSION

APOE can function as an endogenous, concentration-dependent pulmonary danger signal that primes and activates the NLPR3 inflammasome in BALF macrophages from asthmatic subjects to secrete IL-1β. This might represent a mechanism through which APOE amplifies pulmonary inflammatory responses when concentrations in the lung are increased to greater than normal levels, which can occur during viral exacerbations of HDM-induced asthma characterized by neutrophilic airway inflammation.

MBD2 regulates differentiation and function of Th17 cells in neutrophils- dominant asthma via HIF-1α

Background

T helper 17 (Th17) cells have proven to be crucial in the pathogenesis of neutrophils-dominant asthma. Hypoxia inducible factor-1α (HIF-1α) is involved in allergic responses in asthma. Our previous studies indicated that Methtyl-CpG binding domain protein 2 (MBD2) expression was increased in asthma patients. The aim of the present study is to understand how MBD2 interacts with HIF-1α to regulate Th17 cell differentiation and IL-17 expression in neutrophils-dominant asthma.

Methods

A neutrophils-dominant asthma mouse model was established using female C57BL/6 mice to investigate Th17 cell differentiation and MBD2 and HIF-1α expression regulation using flow cytometry, western blot or qRT-PCR. MBD2 and HIF-1α genes were silenced or overexpressed through lentiviral transduction to explore the roles of MBD2 in Th17 cell differentiation and IL-17 release in neutrophils-dominant asthma.

Results

A neutrophilic inflammatory asthma phenotype model was established successfully. This was characterized by airway hyperresponsiveness (AHR), increased BALF neutrophil granulocytes, activated Th17 cell differentiation, and high IL-17 levels. MBD2 and HIF-1α expression were significantly increased in the lung and spleen cells of mice with neutrophils-dominant asthma. Through overexpression or silencing of MBD2 and HIF-1α genes, we have concluded that MBD2 and HIF-1α regulate Th17 cell differentiation and IL-17 secretion. Moreover, MBD2 was also found to regulate HIF-1α expression.

Conclusions

Our findings have uncovered new roles for MBD2 and HIF-1α, and provide novel insights into the epigenetic regulation of neutrophils-dominant asthma.

Electronic supplementary material

The online version of this article (10.1186/s12950-018-0191-x) contains supplementary material, which is available to authorized users.

Insulin-Like Growth Factor-1 Signaling in Lung Development and Inflammatory Lung Diseases

Insulin-like growth factor-1 (IGF-1) was firstly identified as a hormone that mediates the biological effects of growth hormone. Accumulating data have indicated the role of IGF-1 signaling pathway in lung development and diseases such as congenital disorders, cancers, inflammation, and fibrosis. IGF-1 signaling modulates the development and differentiation of many types of lung cells, including airway basal cells, club cells, alveolar epithelial cells, and fibroblasts. IGF-1 signaling deficiency results in alveolar hyperplasia in humans and disrupted lung architecture in animal models. The components of IGF-1 signaling pathways are potentiated as biomarkers as they are dysregulated locally or systemically in lung diseases, whereas data may be inconsistent or even paradoxical among different studies. The usage of IGF-1-based therapeutic agents urges for more researches in developmental disorders and inflammatory lung diseases, as the majority of current data are collected from limited number of animal experiments and are generally less exuberant than those in lung cancer. Elucidation of these questions by further bench-to-bedside researches may provide us with rational clinical diagnostic approaches and agents concerning IGF-1 signaling in lung diseases.

Characterization of the acute inflammatory profile and resolution of airway inflammation after Igf1r-gene targeting in a murine model of HDM-induced asthma

Asthma is a chronic inflammatory disease characterized by bronchial hyperresponsiveness, mucus overproduction and airway remodeling. Notably, we have recently demonstrated that insulin-like growth factor 1 receptor (IGF1R) deficiency in mice attenuates airway hyperresponsiveness and mucus secretion after chronic house dust mite (HDM) exposure. On this basis, inbred C57BL/6 and Igf1r-deficient mice were given HDM extract to study the acute inflammatory profile and implication of Igf1r in acute asthma pathobiology. Additionally, Igf1r-deficiency was therapeutically induced in mice to evaluate the resolution of HDM-induced inflammation. Acute HDM exposure in inbred C57BL/6 mice led to a progressive increase in inflammation, airway remodeling and associated molecular indicators. Preventively-induced Igf1r-deficiency showed reduced neutrophil and eosinophil numbers in BALF and bone marrow, a significant reduction of airway remodeling and decreased levels of related markers. In addition, therapeutic targeting of Igf1r promoted the resolution of HDM-induced-inflammation. Our results demonstrate for the first time that Igf1r is important in acute asthma pathobiology and resolution of HDM-induced inflammation. Thus, IGF1R is suggested to be a promising candidate for future therapeutic approaches for the treatment and prevention of asthma.

Attenuated airway hyperresponsiveness and mucus secretion in HDM-exposed Igf1r-deficient mice

BACKGROUND

Asthma is a common chronic lung disease characterized by airflow obstruction, airway hyperresponsiveness (AHR), and airway inflammation. IGFs have been reported to play a role in asthma, but little is known about how the insulin-like growth factor 1 receptor (IGF1R) affects asthma pathobiology.

METHODS

Female Igf1r-deficient and control mice were intranasally challenged with house dust mite (HDM) extract or PBS five days per week for four weeks. Lung function measurements, and bronchoalveolar lavage fluid (BALF), serum, and lungs were collected on day 28 for further cellular, histological, and molecular analysis.

RESULTS

Following HDM exposure, the control mice responded with a marked AHR and airway inflammation. The Igf1r-deficient mice exhibited an increased expression of the IGF system and surfactant genes, which were decreased in a similar manner for control and Igf1r-deficient mice after HDM exposure. On the other hand, the Igf1r-deficient mice exhibited no AHR, and a selective decrease in blood and BALF eosinophils, lung Il13 levels, collagen, and smooth muscle, as well as a significant depletion of goblet cell metaplasia and mucus secretion markers after HDM exposure. The Igf1r-deficient mice displayed a distinctly thinner epithelial layer than control mice, but this was not altered by HDM.

CONCLUSIONS

Herein, we demonstrate by the first time that the Igf1r plays an important role in murine asthma, mediating both AHR and mucus secretion after HDM exposure. Thus, our study identifies IGF1R as a potential therapeutic target, not only for asthma but also for hypersecretory airway diseases.

MicroRNA-34/449 targets IGFBP-3 and attenuates airway remodeling by suppressing Nur77-mediated autophagy

Autophagy plays critical roles in airway inflammation and fibrosis-mediated airway remodeling and many factors including proinflammatory cytokines and inflammation related pathways are involved in the process. The aim of the present study was to examine the role of epithelial microRNAs (miRNAs) in autophagy-mediated airway remodeling and to identify the factors involved and the underlying mechanisms. Serum miR-34/449, inflammatory factors, and autophagy and fibrosis-related proteins were determined by real-time PCR, enzyme-linked immunosorbent assay and western blotting in 46 subjects with asthma and 10 controls and in the lung epithelial cell line BEAS-2B induced with IL-13 and treated with miRNA mimics. Luciferase assays were used to verify IGFBP-3 as a target of miR-34/449, and immunohistochemistry, immunofluorescence and co-immunoprecipitation were used in vitro and in vivo study. miR-34/449 were downregulated in patients with asthma in parallel with the upregulation of autophagy-related proteins. Proinflammatory factors and fibrosis-related proteins were significantly higher in asthma patients than in healthy controls. IL-13 induction promoted autophagy and upregulated miR-34/449 in BEAS-2B cells, and these effects were restored by IGFBP-3 silencing. miR-34/449 overexpression suppressed autophagy, decreased fibrosis, activated Akt, downregulated fibrosis-related factors, and downregulated proinflammatory cytokines and nuclear factor κB by targeting IGFBP-3. In vivo experiments showed that miR-34/449 overexpression was associated with Nur77 nuclear translocation and IGFBP-3 downregulation in parallel with decreased airway remodeling by decreased autophagy. miR-34/449 are potential biomarkers and therapeutic targets in asthma. miR-34/449 may contribute to airway inflammation and fibrosis by modulating IGFBP-3 mediated autophagy activation.

A phenotype of IGFBP-3 knockout mice revealed by dextran sulfate-induced colitis

BACKGROUND AND AIM

Insulin-like growth factor-1 (IGF-1) bioactivity has been shown to be attenuated by insulin-like growth factor binding protein-3 (IGFBP-3), one of six IGF-binding proteins. While prior work revealed no major phenotype associated with IGFBP-3 knockout mice, we explored the possibility that a phenotype could be revealed under specific conditions of gastrointestinal stress.

METHODS

The dextran sodium sulfate (DSS) murine model of ulcerative colitis was used for this study.

RESULTS

Insulin-like growth factor binding protein-3 knockout mice had significantly reduced colitis on exposure to DSS as measured by lower levels of pro-inflammatory cytokines IL-6 (P < 0.0001), TNF-α (P = 0.0035), and IL-1β (P = 0.0112), reduced weight loss (P < 0.0001), reduced myeloperoxidase activity (P = 0.0025), and maintenance of colorectal length (P < 0.05), all relative to wild-type mice exposed to DSS. IGFBP-3 knockout mice also exhibited increased colon epithelial cell proliferation (P < 0.0001) following DSS exposure. Semi-quantitative immunohistochemistry showed greater IGF-1 receptor activation in colon epithelial cells of IGFBP-3 knockout mice compared with control mice following DSS exposure.

CONCLUSION

Our data demonstrate that IGFBP-3 influences severity of DSS-induced colitis. The observations suggest that in the absence of IGFBP-3, enhanced IGF bioactivity leads to increased epithelial proliferation and mucosal barrier repair, thereby lessening inflammation.

Involvement of Igf1r in Bronchiolar Epithelial Regeneration: Role during Repair Kinetics after Selective Club Cell Ablation

Regeneration of lung epithelium is vital for maintaining airway function and integrity. An imbalance between epithelial damage and repair is at the basis of numerous chronic lung diseases such as asthma, COPD, pulmonary fibrosis and lung cancer. IGF (Insulin-like Growth Factors) signaling has been associated with most of these respiratory pathologies, although their mechanisms of action in this tissue remain poorly understood. Expression profiles analyses of IGF system genes performed in mouse lung support their functional implication in pulmonary ontogeny. Immuno-localization revealed high expression levels of Igf1r (Insulin-like Growth Factor 1 Receptor) in lung epithelial cells, alveolar macrophages and smooth muscle. To further understand the role of Igf1r in pulmonary homeostasis, two distinct lung epithelial-specific Igf1r mutant mice were generated and studied. The lack of Igf1r disturbed airway epithelial differentiation in adult mice, and revealed enhanced proliferation and altered morphology in distal airway club cells. During recovery after naphthalene-induced club cell injury, the kinetics of terminal bronchiolar epithelium regeneration was hindered in Igf1r mutants, revealing increased proliferation and delayed differentiation of club and ciliated cells. Amid airway restoration, lungs of Igf1r deficient mice showed increased levels of Igf1, Insr, Igfbp3 and epithelial precursor markers, reduced amounts of Scgb1a1 protein, and alterations in IGF signaling mediators. These results support the role of Igf1r in controlling the kinetics of cell proliferation and differentiation during pulmonary airway epithelial regeneration after injury.

Drug Signature-based Finding of Additional Clinical Use of LC28-0126 for Neutrophilic Bronchial Asthma

In recent decades, global pharmaceutical companies have suffered from an R&D innovation gap between the increased cost of a new drug’s development and the decreased number of approvals. Drug repositioning offers another opportunity to fill the gap because the approved drugs have a known safety profile for human use, allowing for a reduction of the overall cost of drug development by eliminating rigorous safety assessment. In this study, we compared the transcriptional profile of LC28-0126, an investigational drug for acute myocardial infarction (MI) at clinical trial, obtained from healthy male subjects with molecular activity profiles in the Connectivity Map. We identified dyphilline, an FDA-approved drug for bronchial asthma, as a top ranked connection with LC28-0126. Subsequently, we demonstrated that LC28-0126 effectively ameliorates the pathophysiology of neutrophilic bronchial asthma in OVA_LPS-OVA mice accompanied with a reduction of inflammatory cell counts in the bronchoalveolar lavage fluid (BALF), inhibition of the release of proinflammatory cytokines, relief of airway hyperactivity, and improvement of histopathological changes in the lung. Taken together, we suggest that LC28-0126 could be a potential therapeutic for bronchial asthma. In addition, this study demonstrated the potential general utility of computational drug repositioning using clinical profiles of the investigational drug.

Targeting insulin-like growth factor-I and insulin-like growth factor-binding protein-3 signaling pathways. A novel therapeutic approach for asthma

Insulin-like growth factor (IGF)-I has been recognized to play critical roles in the pathogenesis of asthma, whereas IGF-binding protein (IGFBP)-3 blocks crucial physiologic manifestations of asthma. IGF-I enhances subepithelial fibrosis, airway inflammation, airway hyperresponsiveness, and airway smooth muscle hyperplasia by interacting with various inflammatory mediators and complex signaling pathways, such as intercellular adhesion molecule-1, and the hypoxia-inducible factor/vascular endothelial growth factor axis. On the other hand, IGFBP-3 decreases airway inflammation and airway hyperresponsiveness through IGFBP-3 receptor-mediated activation of caspases, which subsequently inhibits NF-κB signaling pathway. It also inhibits the IGF-I/hypoxia-inducible factor/vascular endothelial growth factor axis via IGF-I-dependent and/or IGF-I-independent mechanisms. This Translational Review summarizes the role of IGF-I and IGFBP-3 in the context of allergic airway disease, and discusses the therapeutic potential of various strategies targeting the IGF-I and IGFBP-3 signaling pathways for the management of asthma.

Immunomodulatory factors and infectious agents associated with the hepatic gene expression of the IGF system in nursery pigs

Recent findings suggest there is a complex interaction between the IGF system and the inflammatory immune response. The objective of this study was to determine whether gene expression of growth factors (IGF-1, IGF-binding protein-3 (IGFBP-3) and growth hormone receptors (GHR)) in the liver is associated with gene expression of immunomodulators in the liver, including C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp), interferon-α (IFN-α), IFN-γ, tumour necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-10 and IL-18, as well as with the presence of Salmonella spp., Lawsonia intracellularis, Brachyspira spp., enterotoxigenic Escherichia coli, methicillin-resistant Staphylococcus aureus, swine influenza virus, and porcine reproductive and respiratory syndrome virus (PRRSV) in nursery pigs (n=74) from commercial farms (n=4). Gene expression was quantified using reverse transcription quantitative-PCR (RT-qPCR) and the data were modelled using logistic regression methods. Pigs with elevated IGF-1 expression were less likely to have increased expression of TNF-α (odds ratio (OR)=0.14, P<0.01) and IL-18 (OR=0.19, P<0.05), and less likely to be colonized with PRRSV (OR=0.03, P<0.01). Pigs with increased expression of IGFBP-3 were more likely to have elevated IL-6 expression (OR=8.5, P<0.05). It was also observed that IGFBP-3 and IGF-1 were significantly associated when Hp expression was low (OR=30, P<0.05), but this association was not significant when Hp expression was high (P=0.54). Pigs with increased expression of GHR were less likely to have elevated expression of SAA (OR=0.01, P<0.05) and IL-1β (OR=0.03, P<0.05), but more likely to have increased expression of CRP (OR=290, P<0.01). Overall, there appears to be an inverse association between the hepatic expression of the IGF system (IGF-1, IGFBP-3, GHR) and certain cytokines (IL-1β, IL-18, TNF-α) and acute-phase proteins (SAA, Hp).

Neuroimmune semaphorin 4A as a drug and drug target for asthma

Neuroimmune semaphorin 4A (Sema4A) has been shown to play an important costimulatory role in T cell activation and regulation of Th1-mediated diseases such as multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE), and experimental autoimmune myocarditis (EAM). Sema4A has three functional receptors, Tim-2 expressed on CD4+ T cells, Th2 cells in particular, and Plexin B1 and D1 predominantly expressed on epithelial and endothelial cells, correspondingly. We recently showed that Sema4A has a complex expression pattern in lung tissue in a mouse model of asthma. We and others have shown that corresponding Plexin expression can be found on immune cells as well. Moreover, we demonstrated that Sema4A-deficient mice displayed significantly higher lung local and systemic allergic responses pointing to its critical regulatory role in the disease. To determine the utility of Sema4A as a novel immunotherapeutic, we introduced recombinant Sema4A protein to the allergen-sensitized WT and Sema4A(-/-) mice before allergen challenge. We observed significant reductions in the allergic inflammatory lung response in Sema4A-treated mice as judged by tissue inflammation including eosinophilia and mucus production. Furthermore, we demonstrated that in vivo administration of anti-Tim2 Ab led to a substantial upregulation of allergic inflammation in WT mouse lungs. These data highlight the potential to develop Sema4A as a new therapeutic for allergic airway disease.

Link between epigenomic alterations and genome-wide aberrant transcriptional response to allergen in dendritic cells conveying maternal asthma risk

We investigated the link between epigenome-wide methylation aberrations at birth and genomic transcriptional changes upon allergen sensitization that occur in the neonatal dendritic cells (DC) due to maternal asthma. We previously demonstrated that neonates of asthmatic mothers are born with a functional skew in splenic DCs that can be seen even in allergen-naïve pups and can convey allergy responses to normal recipients. However, minimal-to-no transcriptional or phenotypic changes were found to explain this alteration. Here we provide in-depth analysis of genome-wide DNA methylation profiles and RNA transcriptional (microarray) profiles before and after allergen sensitization. We identified differentially methylated and differentially expressed loci and performed manually-curated matching of methylation status of the key regulatory sequences (promoters and CpG islands) to expression of their respective transcripts before and after sensitization. We found that while allergen-naive DCs from asthma-at-risk neonates have minimal transcriptional change compared to controls, the methylation changes are extensive. The substantial transcriptional change only becomes evident upon allergen sensitization, when it occurs in multiple genes with the pre-existing epigenetic alterations. We demonstrate that maternal asthma leads to both hyper- and hypomethylation in neonatal DCs, and that both types of events at various loci significantly overlap with transcriptional responses to allergen. Pathway analysis indicates that approximately 1/2 of differentially expressed and differentially methylated genes directly interact in known networks involved in allergy and asthma processes. We conclude that congenital epigenetic changes in DCs are strongly linked to altered transcriptional responses to allergen and to early-life asthma origin. The findings are consistent with the emerging paradigm that asthma is a disease with underlying epigenetic changes.

Vascular endothelial growth factor as a key inducer of angiogenesis in the asthmatic airways

Asthma is a chronic inflammatory disease of the airways characterized by structural airway changes, which are known as airway remodeling, including smooth muscle hypertrophy, goblet cell hyperplasia, subepithelial fibrosis, and angiogenesis. Vascular remodeling in asthmatic lungs results from increased angiogenesis, which is mainly mediated by vascular endothelial growth factor (VEGF). VEGF is a key regulator of blood vessel growth in the airways of asthma patients by promoting proliferation and differentiation of endothelial cells and inducing vascular leakage and permeability. In addition, VEGF induces allergic inflammation, enhances allergic sensitization, and has a role in Th2 type inflammatory responses. Specific inhibitors of VEGF and blockers of its receptors might be useful to control chronic airway inflammation and vascular remodeling, and might be a new therapeutic approach for chronic inflammatory airway disease like asthma.

Chronic activation of vasopressin V2 receptor signalling lowers renal medullary oxygen levels in rats

AIM

In the present study, we aimed to elucidate the effects of chronic vasopressin administration on renal medullary oxygen levels.

METHODS

Adult Sprague Dawley or vasopressin-deficient Brattleboro rats were treated with the vasopressin V2 receptor agonist, desmopressin (5 ng/h; 3d), or its vehicle via osmotic minipumps. Immunostaining for pimonidazole and the transcription factor HIF-1α (hypoxia-inducible factor-1α) were used to identify hypoxic areas. Activation of HIF-target gene expression following desmopressin treatment was studied by microarray analysis.

RESULTS

Pimonidazole staining was detected in the outer and inner medulla of desmopressin-treated rats, whereas staining in control animals was weak or absent. HIF-1α immunostaining demonstrated nuclear accumulation in the papilla of desmopressin-treated animals, whereas no staining was observed in the controls. Gene expression analysis revealed significant enrichment of HIF-target genes in the group of desmopressin-regulated gene products (P = 2.6*10(-21) ). Regulated products included insulin-like growth factor binding proteins 1 and 3, angiopoietin 2, fibronectin, cathepsin D, hexokinase 2 and cyclooxygenase 2.

CONCLUSION

Our results demonstrate that an activation of the renal urine concentrating mechanism by desmopressin causes renal medullary hypoxia and an upregulation of hypoxia-inducible gene expression.

Novel insights into mechanisms of food allergy and allergic airway inflammation using experimental mouse models

Over the last decades, considerable efforts have been undertaken in the development of animal models mimicking the pathogenesis of allergic diseases occurring in humans. The mouse has rapidly emerged as the animal model of choice, due to considerations of handling and costs and, importantly, due to the availability of a large and increasing arsenal of genetically modified mouse strains and molecular tools facilitating the analysis of complex disease models. Here, we review latest developments in allergy research that have arisen from in vivo experimentation in the mouse, with a focus on models of food allergy and allergic asthma, which constitute major health problems with increasing incidence in industrialized countries. We highlight recent novel findings and controversies in the field, most of which were obtained through the use of gene-deficient or germ-free mice, and discuss new potential therapeutic approaches that have emerged from animal studies and that aim at attenuating allergic reactions in human patients.