Role of the adiponectin binding protein, T-cadherin (Cdh13), in allergic airways responses in mice

Serum levels of HMW adiponectin and its receptors are associated with cytokine levels and clinical characteristics in chronic obstructive pulmonary disease

We aimed to investigate the changes in the levels of high-molecular-weight (HMW) adiponectin, adiponectin receptors, and cytokines in patients with chronic obstructive pulmonary disease (COPD), as well as their potential relationships. Forty-one patients who underwent lobectomy for lung lesions and had a clear postoperative pathological diagnosis were divided into the non-COPD (N = 23) and COPD (N = 18) groups. HMW adiponectin, cytokine, and T-cadherin levels in serum and tissues were detected by enzyme-linked immunosorbent assay. The levels of HMW adiponectin and cytokine (interleukin [IL]-6, IL-10, surfactant protein D, 4-hydroxynonenal, tumor necrosis factor-α, and C reactive protein) in the serum and tissues increased in the COPD group compared to those in the non-COPD group. Patients with COPD exhibited AdipoR1 upregulation and AdipoR2 downregulation. Although T-cadherin did not differ significantly between patients with and those without COPD, its expression was elevated during the progression from COPD with benign lung lesions to combined lung cancer. Furthermore, the HMW adiponectin levels were significantly correlated with the cytokine levels and the clinical characteristics of COPD. HMW adiponectin and its receptors affect the inflammatory process in COPD and may further contribute to the progression of the disease to malignancy.

Therapeutic ketosis decreases methacholine hyperresponsiveness in mouse models of inherent obese asthma

Obese asthmatics tend to have severe, poorly controlled disease and exhibit methacholine hyperresponsiveness manifesting in proximal airway narrowing and distal lung tissue collapsibility. Substantial weight loss in obese asthmatics or in mouse models of the condition decreases methacholine hyperresponsiveness. Ketone bodies are rapidly elevated during weight loss, coinciding with or preceding relief from asthma-related comorbidities. As ketone bodies may exert numerous potentially therapeutic effects, augmenting their systemic concentrations is being targeted for the treatment of several conditions. Circulating ketone body levels can be increased by feeding a ketogenic diet or by providing a ketone ester dietary supplement, which we hypothesized would exert protective effects in mouse models of inherent obese asthma. Weight loss induced by feeding a low-fat diet to mice previously fed a high-fat diet was preceded by increased urine and blood levels of the ketone body β-hydroxybutyrate (BHB). Feeding a ketogenic diet for 3 wk to high-fat diet-fed obese mice or genetically obese db/db mice increased BHB concentrations and decreased methacholine hyperresponsiveness without substantially decreasing body weight. Acute ketone ester administration decreased methacholine responsiveness of normal mice, and dietary ketone ester supplementation of high-fat diet-fed mice decreased methacholine hyperresponsiveness. Ketone ester supplementation also transiently induced an "antiobesogenic" gut microbiome with a decreased Fermicutes/Bacteroidetes ratio. Dietary interventions to increase systemic BHB concentrations could provide symptom relief for obese asthmatics without the need for the substantial weight loss required of patients to elicit benefits to their asthma through bariatric surgery or other diet or lifestyle alterations.

Regulatory Peptides in Asthma

Numerous regulatory peptides play a critical role in the pathogenesis of airway inflammation, airflow obstruction and hyperresponsiveness, which are hallmarks of asthma. Some of them exacerbate asthma symptoms, such as neuropeptide Y and tachykinins, while others have ameliorating properties, such as nociception, neurotensin or β-defensin 2. Interacting with peptide receptors located in the lungs or on immune cells opens up new therapeutic possibilities for the treatment of asthma, especially when it is resistant to available therapies. This article provides a concise review of the most important and current findings regarding the involvement of regulatory peptides in asthma pathology.

The Secretome of Human Neonatal Mesenchymal Stem Cells Modulates Doxorubicin-Induced Cytotoxicity: Impact in Non-Tumor Cells

Doxorubicin (Dox) is one of the most widely used treatments for breast cancer, although limited by the well-documented cardiotoxicity and other off-target effects. Mesenchymal stem cell (MSC) secretome has shown immunomodulatory and regenerative properties, further potentiated under 3D conditions. This work aimed to uncover the effect of the MSC-derived secretome from 3D (CM3D) or 2D (CM2D) cultures, in human malignant breast cells (MDA-MB-231), non-tumor breast epithelial cells (MCF10A) and differentiated AC16 cardiomyocytes, co-treated with Dox. A comprehensive proteomic analysis of CM3D/CM2D was also performed to unravel the underlying mechanism. CM3D/CM2D co-incubation with Dox revealed no significant differences in MDA-MB-231 viability when compared to Dox alone, whereas MCF10A and AC16 viability was consistently improved in Dox+CM3D-treated cells. Moreover, neither CM2D nor CM3D affected Dox anti-migratory and anti-invasive effects in MDA-MB-231. Notably, Ge-LC-MS/MS proteomic analysis revealed that CM3D displayed protective features that might be linked to the regulation of cell proliferation (CAPN1, CST1, LAMC2, RANBP3), migration (CCN3, MMP8, PDCD5), invasion (TIMP1/2), oxidative stress (COX6B1, AIFM1, CD9, GSR) and inflammation (CCN3, ANXA5, CDH13, GDF15). Overall, CM3D decreased Dox-induced cytotoxicity in non-tumor cells, without compromising Dox chemotherapeutic profile in malignant cells, suggesting its potential use as a chemotherapy adjuvant to reduce off-target side effects.

Adiponectin and Asthma: Knowns, Unknowns and Controversies

Adiponectin is an adipokine associated with the healthy obese phenotype. Adiponectin increases insulin sensitivity and has cardio and vascular protection actions. Studies related to adiponectin, a modulator of the innate and acquired immunity response, have suggested a role of this molecule in asthma. Studies based on various asthma animal models and on the key cells involved in the allergic response have provided important insights about this relation. Some of them indicated protection and others reversed the balance towards negative effects. Many of them described the cellular pathways activated by adiponectin, which are potentially beneficial for asthma prevention or for reduction in the risk of exacerbations. However, conclusive proofs about their efficiency still need to be provided. In this article, we will, briefly, present the general actions of adiponectin and the epidemiological studies supporting the relation with asthma. The main focus of the current review is on the mechanisms of adiponectin and the impact on the pathobiology of asthma. From this perspective, we will provide arguments for and against the positive influence of this molecule in asthma, also indicating the controversies and sketching out the potential directions of research to complete the picture.

Compensation of Adiponectin-Induced Adenosine Monophosphate-Activated Protein Kinase and p38 Mitogen-Activated Protein Kinase Signaling in Rheumatoid Arthritis Synovial Fibroblasts

Rheumatoid arthritis (RA) is a chronic inflammatory disorder marked by synovitis, ultimately leading to cartilage and bone destruction. In RA, adiponectin levels are increased in serum and synovial fluid. Adiponectin belongs to the adipokines, a group of highly bioactive substances secreted by adipocytes and other cell types. It has been shown to induce the production of proinflammatory and prodestructive factors by human RA synovial fibroblasts (RASF), suggesting a role in the pathophysiology of the disease. Although adenosine monophosphate-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase (MAPK) are known to be involved in adiponectin signaling in RASF, no literature is available about whether the different adiponectin isoforms affect AMPK and p38 MAPK signaling in the same manner. In this study, we elucidated the signaling mechanisms in RASF, activated in response to selective stimulation with the 2 biologically most potent adiponectin isoforms, and possible approaches to inhibit adiponectin-mediated effects in RASF. All adiponectin isoforms induced p38 MAPK and AMPK phosphorylation to various degrees. Blocking AMPK activation increased p38 MAPK phosphorylation, while blocking p38 MAPK activation increased AMPK phosphorylation, both independent of the effect of adiponectin. Neither AMPKα1 nor AMPKα2 knockdown reduced interleukin (IL)-6/IL-8 release. Targeting transforming growth factor-activated kinase 1 (TAK1), a signaling molecule upstream of p38 MAPK, reduced the IL-6/IL-8 release. Taken together, our study showed that, in the case of adiponectin isoforms, inhibiting the p38 MAPK or the AMPK signaling pathway individually is not sufficient, probably due to compensatory interactions between these pathways. TAK1 might provide an alternative approach by ameliorating the proinflammatory effects of adiponectin in RA. Our results do not suggest that targeting individual adiponectin isoforms specifically in RA would provide a benefit over targeting adiponectin as a whole. However, whether targeting individual adiponectin isoforms would allow minimizing the loss of the beneficial effects of adiponectin within the metabolic and cardiovascular system still needs further investigation.

RNA-Seq Expression Analysis of Chronic Asthmatic Mice with Bu-Shen-Yi-Qi Formula Treatment and Prediction of Regulated Gene Targets of Anti-Airway Remodeling

Airway remodeling is one of the typical pathological characteristics of asthma, while the structural changes of the airways in asthma are complex, which impedes the development of novel asthma targeted therapy. Our previous study had shown that Bu-Shen-Yi-Qi formula (BSYQF) could ameliorate airway remodeling in chronic asthmatic mice by modulating airway inflammation and oxidative stress in the lung. In this study, we analysed the lung transcriptome of control mice and asthmatic mouse model with/without BSYQF treatment. Using RNA-sequencing (RNA-seq) analysis, we found that 264/1746 (15.1%) of transcripts showing abnormal expression in asthmatic mice were reverted back to completely or partially normal levels by BSYQF treatment. Additionally, based on previous results, we identified 21 differential expression genes (DEGs) with fold changes (FC) > (±) 2.0 related to inflammatory, oxidative stress, mitochondria, PI3K/AKT, and MAPK signal pathways which may play important roles in the mechanism of the anti-remodeling effect of BSYQF treatment. Through inputting 21 DEGs into the IPA database to construct a gene network, we inferred Adipoq, SPP1, and TNC which were located at critical nodes in the network may be key regulators of BSYQF's anti-remodeling effect. In addition, the quantitative real-time polymerase chain reaction (qRT-PCR) result for the selected four DEGs matched those of the RNA-seq analysis. Our results provide a preliminary clue to the molecular mechanism of the anti-remodeling effect of BSYQF in asthma.

Contentious role of 'Good Adiponectin' in pulmonary and cardiovascular diseases: Is adiponectin directed therapy a boon or a bane?

After two decades of its discovery, numerous facts of adiponectin (APN) biology has been uncovered, yet, APN remains an elusive adipokine. Findings from clinical studies and animal models established APN's ameliorative role in cardiovascular disease (CVD) and pulmonary disease (PD) but the same condition is prognostic for mortality in the same set of patients which cornered APN towards a dubious state. A repertoire of mechanisms associated with the positive association of APN in both lean/cachectic or obese CVD and PD patients from past publications are evaluated. Newer pharmacological agent may be explored to regulate elevated blood APN concentration in COPD or CHF patients whereas administration of recombinant APN as well as growth hormone may augment blood APN concentration in obese subjects associated with low blood and intracellular APN concentration. However, some APN directed therapy in clinical as well as in pre-clinical setup has pronounced some contentious effects. After reviewing the mechanisms of the contentious role of APN functioning in pathologic conditions of CVD and PD in both lean and obese conditions, the authors came to conclusion that APN directed therapy may be utilized with caution keeping in mind the different age group, sex and the different CVD as well as pulmonary diseases they are suffering from.

Admixture mapping of asthma in southwestern Europeans with North African ancestry influences

The prevalence of asthma symptoms in Canary Islanders, a southwestern European population from Spain, is almost three times higher than the country average. Because the genetic risks identified so far explain <5% of asthma heritability, here we aimed to discover new asthma loci by completing the first admixture mapping study in Canary Islanders leveraging their distinctive genetic makeup, where significant northwest African influences coexist in the European genetic diversity landscape. A 2-stage study was conducted in 1,491 unrelated individuals self-declaring having a Canary Islands origin for the 4 grandparents. Local ancestry estimates were obtained for the shared positions with reference data from putative ancestral populations from Europe, North Africa, and sub-Saharan Africa. Case-control deviations in local ancestry were tested for each ancestry separately using logistic regressions adjusted for principal components, followed by fine-mapping analyses based on imputed genotypes and analyses of the likely deleterious exonic variants. The admixture mapping analysis of asthma detected that local North African ancestry in a locus spanning 365 kb of chromosome 16q23.3 was associated with asthma risk at study-wide significance [lowest P = 1.12 × 10^-4; odds ratio (OR) = 2.05; 95% confidence interval (CI) = 1.41-3.00]. Fine-mapping studies identified a variant associated with asthma, and results were replicated in independent samples (rs3852738, OR = 1.34; 95% CI = 1.13-1.59, P = 7.58 × 10^-4). Whole exome sequencing data from a subset of individuals revealed an enrichment of likely deleterious variants among asthma cases in 16q23.3, particularly in the phospholipase Cγ2 (PLCG2) gene (P = 3.67 × 10^-4). By completing the first mapping study of asthma in admixed populations from Europe, our results revealed a new plausible asthma locus.

[Obesity and asthma: Mechanisms and therapeutic options]

Asthma and obesity are both common conditions, which lead to a substantial public health burden. The obese-asthma phenotype is characterized by poor asthma control, impaired lung function and decreased efficacy of inhaled treatment. However, this phenotype is highly heterogeneous and involves numerous mechanisms, including systemic inflammation and adipokines. A role for microbiota modifications and genetics has been suggested. Obese-asthma patient management currently consists in weight loss and usual anti-asthmatic treatment. New therapeutic options are being evaluated.

Targeting cell signaling in allergic asthma

Asthma is chronic inflammation of the airways characterized by airway hyper-responsiveness, wheezing, cough, and dyspnea. Asthma affects >350 million people worldwide. The Th2 immune response is a major contributor to the pathophysiology of asthma. Targeted therapy modulating cell signaling pathways can be a powerful strategy to design new drugs to treat asthma. The potential molecular pathways that can be targeted include IL-4-IL-13-JAK-STAT-MAP kinases, adiponectin-iNOS-NF-κB, PGD2-CRTH2, IFNs-RIG, Wnt/β-catenin-FAM13A, FOXC1-miR-PI3K/AKT, JNK-Gal-7, Nrf2-ROS, Foxp3-RORγt, CysLTR, AMP, Fas-FasL, PTHrP/PPARγ, PAI-1, FcɛRI-LAT-SLP-76, Tim-3-Gal-9, TLRs-MyD88, PAR2, and Keap1/Nrf2/ARE. Therapeutic drugs can be designed to target one or more of these pathways to treat asthma.

Exome-Derived Adiponectin-Associated Variants Implicate Obesity and Lipid Biology

Circulating levels of adiponectin, an adipocyte-secreted protein associated with cardiovascular and metabolic risk, are highly heritable. To gain insights into the biology that regulates adiponectin levels, we performed an exome array meta-analysis of 265,780 genetic variants in 67,739 individuals of European, Hispanic, African American, and East Asian ancestry. We identified 20 loci associated with adiponectin, including 11 that had been reported previously (p < 2 × 10^-7). Comparison of exome array variants to regional linkage disequilibrium (LD) patterns and prior genome-wide association study (GWAS) results detected candidate variants (r² > .60) spanning as much as 900 kb. To identify potential genes and mechanisms through which the previously unreported association signals act to affect adiponectin levels, we assessed cross-trait associations, expression quantitative trait loci in subcutaneous adipose, and biological pathways of nearby genes. Eight of the nine loci were also associated (p < 1 × 10^-4) with at least one obesity or lipid trait. Candidate genes include PRKAR2A, PTH1R, and HDAC9, which have been suggested to play roles in adipocyte differentiation or bone marrow adipose tissue. Taken together, these findings provide further insights into the processes that influence circulating adiponectin levels.

Pharmacogenomics of chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition, which presents the opportunity for precision therapy based on genetics or other biomarkers. Areas covered: Alpha-1 antitrypsin deficiency, a genetic form of emphysema, provides an example of this precision approach to diagnosis and therapy. To date, research in COPD pharmacogenomics has been limited by small sample sizes, lack of accessible target tissue, failure to consider COPD subtypes, and different outcomes relevant for various medications. There have been several published genome-wide association studies and other omics studies in COPD pharmacogenomics; however, clinical implementation remains far away. There is a growing evidence base for precision prescription of inhaled corticosteroids in COPD, based on clinical phenotypes and blood biomarkers, but not yet based on pharmacogenomics. Expert opinion: At this time, there is insufficient evidence for clinical implementation of COPD pharmacogenomics. Additional genome-wide studies will be required to discover predictors of drug response and to identify genomic biomarkers of COPD subtypes, which could be targeted with subtype-directed therapies.

Adiponectin alleviates exacerbation of airway inflammation and oxidative stress in obesity-related asthma mice partly through AMPK signaling pathway

Adiponectin plays a role in asthma and obesity, but its effects and mechanism in obesity-related asthma remain elusive. This study aimed to evaluate the effects of adiponectin on airway inflammation and oxidative stress and to determine its mechanism in obesity-related asthma. Male C57BL6/J mice fed with a high-fat diet to induce obesity were sensitized and challenged with ovalbumin to induce asthma, and treated with adiponectin (1 mg/kg) and AMP-activated protein kinase (AMPK) inhibitor compound C (20 mg/kg) twice before the first ovalbumin challenge. We found exogenous adiponectin significantly reduced airway resistance, inflammatory infiltration in lung tissue, and cell counts in bronchoalveolar lavage fluid. Adiponectin inhibited great levels of eotaxin, myeloperoxidase, tumor necrosis factor-α, 8‑hydroxy‑2'‑deoxyguanosine, and nitric oxide in obesity-related asthma mice. Moreover, we found increased nuclear factor kappa B p65, inducible nitric oxide synthase and B-cell lymphoma 2 protein expression were down-regulated with adiponectin administration. Additionally, adiponectin elevated the lower levels of pAMPK and AMPK activity in lung tissue. These protective effects of adiponectin were reversed after treatment with the AMPK inhibitor compound C. Thus, we conclude that adiponectin alleviates exacerbation of airway inflammation and oxidative stress in a murine model of obesity-related asthma partly through AMPK signaling pathway.

Mechanisms of Asthma in Obesity. Pleiotropic Aspects of Obesity Produce Distinct Asthma Phenotypes

The majority of patients with severe or difficult-to-control asthma in the United States are obese. Epidemiological studies have clearly established that obese patients tend to have worse asthma control and increased hospitalizations and do not respond to standard controller therapy as well as lean patients with asthma. Less clear are the mechanistic underpinnings for the striking clinical differences between lean and obese patients with asthma. Because obesity is principally a disorder of metabolism and energy regulation, processes fundamental to the function of every cell and system within the body, it is not surprising that it affects the respiratory system; it is perhaps surprising that it has taken so long to appreciate how dysfunctional metabolism and energy regulation lead to severe airway disease. Although early investigations focused on identifying a common factor in obesity that could promote airway disease, an appreciation has emerged that the asthma of obesity is a manifestation of multiple anomalies related to obesity affecting all the different pathways that cause asthma, and likely also to de novo airway dysfunction. Consequently, all the phenotypes of asthma currently recognized in lean patients (which are profoundly modified by obesity), as well as those unique to one's obesity endotype, likely contribute to obese asthma in a particular individual. This perspective reviews what we have learned from clinical studies and animal models about the phenotypes of asthma in obesity, which show how specific aspects of obesity and altered metabolism might lead to de novo airway disease and profoundly modify existing airway disease.

Integrative information theoretic network analysis for genome-wide association study of aspirin exacerbated respiratory disease in Korean population

BACKGROUND

Aspirin Exacerbated Respiratory Disease (AERD) is a chronic medical condition that encompasses asthma, nasal polyposis, and hypersensitivity to aspirin and other non-steroidal anti-inflammatory drugs. Several previous studies have shown that part of the genetic effects of the disease may be induced by the interaction of multiple genetic variants. However, heavy computational cost as well as the complexity of the underlying biological mechanism has prevented a thorough investigation of epistatic interactions and thus most previous studies have typically considered only a small number of genetic variants at a time.

METHODS

In this study, we propose a gene network based analysis framework to identify genetic risk factors from a genome-wide association study dataset. We first derive multiple single nucleotide polymorphisms (SNP)-based epistasis networks that consider marginal and epistatic effects by using different information theoretic measures. Each SNP epistasis network is converted into a gene-gene interaction network, and the resulting gene networks are combined as one for downstream analysis. The integrated network is validated on existing knowledgebase of DisGeNET for known gene-disease associations and GeneMANIA for biological function prediction.

RESULTS

We demonstrated our proposed method on a Korean GWAS dataset, which has genotype information of 440,094 SNPs for 188 cases and 247 controls. The topological properties of the generated networks are examined for scale-freeness, and we further performed various statistical analyses in the Allergy and Asthma Portal (AAP) using the selected genes from our integrated network.

CONCLUSIONS

Our result reveals that there are several gene modules in the network that are of biological significance and have evidence for controlling susceptibility and being related to the treatment of AERD.

Role of ROCK2 in CD4+ cells in allergic airways responses in mice

BACKGROUND

Rho kinases (ROCKs) contribute to allergic airways disease. ROCKs also play a role in lymphocyte proliferation and migration.

OBJECTIVE

To determine the role of ROCK2 acting within CD4+ cells in allergic airways responses.

METHODS

ROCK2-haploinsufficient (ROCK2+/- ) and wild-type mice were sensitized with ovalbumin (OVA). ROCK2+/- mice then received either CD4+ cells from ROCK2-sufficient OVA TCR transgenic (OT-II) mice or saline i.v. 48 h before challenge with aerosolized OVA. Wild-type mice received saline before challenge. Allergic airways responses were measured 48 h after the last challenge. Allergic airways responses were also assessed in mice lacking ROCK2 only in CD4+ cells (ROCK2CD4Cre mice) vs. control (CD4-Cre and ROCK2flox/flox ) mice.

RESULTS

OVA-induced increases in bronchoalveolar lavage lymphocytes, eosinophils, IL-13, IL-5, and eotaxin were reduced in ROCK2+/- vs. wild-type mice, as were airway hyperresponsiveness and mucous hypersecretion. In ROCK2+/- mice, adoptive transfer with CD4+ cells from OT-II mice restored effects of OVA on lymphocytes, eosinophils, IL-13, IL-5, and mucous hypersecretion to wild-type levels, whereas eotaxin and airway hyperresponsiveness were not affected. ROCK2 inhibitors reduced IL-13-induced release of eotaxin from airway smooth muscle (ASM), similar to effects of these inhibitors on ASM contractility. Despite the ability of adoptive transfer to restore allergic airways inflammation in ROCK2-insufficient mice, allergic inflammation was not different in ROCK2CD4Cre vs. control mice.

CONCLUSION

ROCK2 contributes to allergic airways responses likely via effects within ASM cells and within non-lymphocyte cells involved in lymphocyte activation and migration into the airways.

The burden of obesity in asthma and COPD: Role of adiponectin

The influence of obesity on development, severity and prognosis of both asthma and COPD is attracting growing interest. The impact of obesity on the respiratory system ranges from structural modifications (decline of total lung capacity) to humoral alterations. Adipose tissue strongly contributes to the establishment of an inflammatory state being an important source of adipokines. Amongst adipokines, adiponectin is an important component of organ cross talk with adipose tissue exerting protective effects on a variety of pathophysiological processes. Adiponectin is secreted in serum where it abundantly circulates as complexes of different molecular weight. Adiponectin properties are mediated by specific receptors that are widely expressed with AdipoR1, AdipoR2, and T-cadherin being present on epithelial and endothelial pulmonary cells indicating a functional role on lung physiology. In COPD, mild to moderate obesity has been shown to have protective effects on patient's survival, while a higher mortality rate has been observed in patients with low BMI. A specific cluster of obese patients has been identified; in this group, asthma features are particularly severe and difficult to treat. Better understanding of the molecular mechanisms at the base of cross talk among different tissues and organs will lead to identification of new targets for both diagnosis and treatment of asthma and COPD.

Cadherin 13: human cis-regulation and selectively-altered addiction phenotypes and cerebral cortical dopamine in knockout mice

The cadherin 13 (CDH13) gene encodes a cell adhesion molecule likely to influence development and connections of brain circuits that modulate addiction, locomotion and cognition, including those that involve midbrain dopamine neurons. Human CDH13 mRNA expression differs by more than 80% in postmortem cerebral cortical samples from individuals with different CDH13 genotypes, supporting examination of mice with altered Cdh13 expression as models for common human variation at this locus. Constitutive cdh13 knockout mice display evidence for changed cocaine reward: shifted dose response relationship in tests of cocaine-conditioned place preference using doses that do not alter cocaine conditioned taste aversion. Reduced adult Cdh13 expression in conditional knockouts also alters cocaine reward in ways that correlate with individual differences in cortical Cdh13 mRNA levels. In control and comparison behavioral assessments, knockout mice display modestly-quicker acquisition of rotarod and water maze tasks, with a trend toward faster acquisition of 5 choice serial reaction time tasks that otherwise displayed no genotype-related differences. They display significant differences in locomotion in some settings, with larger effects in males. In assessments of brain changes that might contribute to these behavioral differences, there are selective alterations of dopamine levels, dopamine/metabolite ratios, dopaminergic fiber densities and mRNA encoding the activity dependent transcription factor npas4 in cerebral cortex of knockout mice. These novel data and previously reported human associations of CDH13 variants with addiction, individual differences in responses to stimulant administration and attention deficit hyperactivity disorder (ADHD) phenotypes suggest that levels of CDH13 expression, through mechanisms likely to include effects on mesocortical dopamine, influence stimulant reward and may contribute modestly to cognitive and locomotor phenotypes relevant to ADHD.

IL-13 Augments Compressive Stress-Induced Tissue Factor Expression in Human Airway Epithelial Cells

Tissue factor (TF) is best known as a cellular initiator of coagulation, but it is also a multifunctional protein that has been implicated in multiple pathophysiologic conditions, including asthma. In the lung, airway epithelial cells express TF, but it is unknown how TF expression is regulated by asthma-associated mediators. We investigated the role of IL-13, a type 2 cytokine, alone and in combination with compressive stress, which mimics asthmatic bronchoconstriction, on TF expression and release of TF-positive extracellular vesicles from primary normal human bronchial epithelial cells. Well-differentiated normal human bronchial epithelial cells were treated with IL-13 and compressive stress, alone and in combination. TF mRNA, protein and activity were measured in the cells and conditioned media. TF was also measured in the bronchoalveolar lavage (BAL) fluid of allergen-challenged mice and patients with asthma. IL-13 and compressive stress increased TF expression, but only compressive stress induced TF-positive extracellular vesicle release. Pretreatment with IL-13 augmented compressive stress-induced TF expression and release. TF protein and activity in BAL fluid were increased in allergen-sensitized and -challenged mice. TF was elevated in the BAL fluid of patients with mild asthma after an allergen challenge. Our in vitro and in vivo data indicate close cooperation between mechanical and inflammatory stimuli on TF expression and release of TF-positive extracellular vesicles in the lungs, which may contribute to pathophysiology of asthma.

A genome-wide analysis of the response to inhaled β2-agonists in chronic obstructive pulmonary disease

Short-acting β2-agonist bronchodilators are the most common medications used in treating chronic obstructive pulmonary disease (COPD). Genetic variants determining bronchodilator responsiveness (BDR) in COPD have not been identified. We performed a genome-wide association study (GWAS) of BDR in 5789 current or former smokers with COPD in one African-American and four white populations. BDR was defined as the quantitative spirometric response to inhaled β2-agonists. We combined results in a meta-analysis. In the meta-analysis, single-nucleotide polymorphisms (SNPs) in the genes KCNK1 (P=2.02 × 10(-7)) and KCNJ2 (P=1.79 × 10(-7)) were the top associations with BDR. Among African Americans, SNPs in CDH13 were significantly associated with BDR (P=5.1 × 10(-9)). A nominal association with CDH13 was identified in a gene-based analysis in all subjects. We identified suggestive association with BDR among COPD subjects for variants near two potassium channel genes (KCNK1 and KCNJ2). SNPs in CDH13 were significantly associated with BDR in African Americans.The Pharmacogenomics Journal advance online publication, 27 October 2015; doi:10.1038/tpj.2015.65.

AdipoR-increased intracellular ROS promotes cPLA2 and COX-2 expressions via activation of PKC and p300 in adiponectin-stimulated human alveolar type II cells

Adiponectin, an adipokine, accumulated in lung system via T-cadherin after allergens/ozone challenge. However, the roles of adiponectin on lung pathologies were controversial. Here we reported that adiponectin stimulated expression of inflammatory proteins, cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), and production of reactive oxygen species (ROS) in human alveolar type II A549 cells. AdipoR1/2 involved in adiponectin-activated NADPH oxidase and mitochondria, which further promoted intracellular ROS accumulation. Protein kinase C (PKC) may involve an adiponectin-activated NADPH oxidase. Similarly, p300 phosphorylation and histone H4 acetylation occurred in adiponectin-challenged A549 cells. Moreover, adiponectin-upregulated cPLA2 and COX-2 expression was significantly abrogated by ROS scavenger (N-acetylcysteine) or the inhibitors of NADPH oxidase (apocynin), mitochondrial complex I (rotenone), PKC (Ro31-8220, Gö-6976, and rottlerin), and p300 (garcinol). Briefly, we reported that adiponectin stimulated cPLA2 and COX-2 expression via AdipoR1/2-dependent activation of PKC/NADPH oxidase/mitochondria resulting in ROS accumulation, p300 phosphorylation, and histone H4 acetylation. These results suggested that adiponectin promoted lung inflammation, resulting in exacerbation of pulmonary diseases via upregulating cPLA2 and COX-2 expression together with intracellular ROS production. Understanding the adiponectin signaling pathways on regulating cPLA2 and COX-2 may help develop therapeutic strategies on pulmonary diseases.

Obesity shifts house dust mite-induced airway cellular infiltration from eosinophils to macrophages: effects of glucocorticoid treatment

Although classically characterized by chronic airway inflammation with eosinophil infiltration, asthma is a complex and multifactorial condition with numerous clinical phenotypes. Epidemiological studies strongly support the link between obesity and asthma and suggest that obesity precedes and promotes asthma development, increases asthma severity, and reduces steroid responsivity. Using a house dust mite (HDM) model of airway hyperresponsiveness in C57BL/6 mice, we examined the effects of diet-induced obesity on allergic airway inflammation and its treatment with dexamethasone. When compared to lean mice treated with HDM, obese-HDM mice had reduced plasma adiponectin, an anti-inflammatory adipokine, lower eosinophil and higher macrophage infiltration into the lungs and bronchoalveolar lavage (BAL) fluid, increased expression of total, M1, and M2 macrophage markers in the lungs, and enhanced Th2 and non-Th2 cytokine expression in the lungs. While Th2-associated responses in obese-HDM mice were suppressed by systemic dexamethasone, several Th2-independent responses, including total and M1 macrophage markers in the lungs, and lung CXC-motif ligand 1 (CXCL1) levels, were not improved following dexamethasone treatment. Thus, HDM combined with obesity promotes mixed localized inflammatory responses (e.g., M1, M2, Th1, and Th2) and shifts the cellular infiltration from eosinophils to macrophages, which are less sensitive to dexamethasone regulation. Because obese asthmatics exhibit more severe symptoms, lack a predominance of Th2 biomarkers, and are predicted to experience more steroid resistance when compared to lean asthmatics, this model could be used to study blunted steroid responses in obese-HDM mice and to define the macrophages found in the lungs.

A pilot randomized controlled trial of pioglitazone for the treatment of poorly controlled asthma in obesity

BACKGROUND

Obese asthmatics tend to have poorly controlled asthma, and resistance to standard asthma controller medications. The purpose of this study was to determine the efficacy of pioglitazone, an anti-diabetic medication which can alter circulating adipokines and have direct effects on asthmatic inflammation, in the treatment of asthma in obesity.

METHODS

A two-center, 12-week, randomized, placebo-controlled, double-blinded trial. Treatments were randomly assigned with concealment of allocation. The primary outcome was difference in change in airway reactivity between participants assigned to pioglitazone versus placebo at 12 weeks.

RESULTS

Twenty-three participants were randomized to treatment, 19 completed the study. Median airway reactivity, measured by PC20 to methacholine was 1.99 (IQR 3.08) and 1.60 (5.91) mg/ml in placebo and pioglitazone group at baseline, and 2.37 (15.22) and 5.08 (7.42) mg/ml after 12 weeks, p = 0.38. There was no difference in exhaled nitric oxide, asthma control or lung function between treatment groups over the 12 week trial. Participants assigned to pioglitazone gained a significant amount more weight than those assigned to placebo (pioglitazone group mean weight 113.6, CI 94.5-132.7 kg at randomization and 115.9, CI 96.9-135.1 at 12 weeks; placebo mean weight 127.5, CI 108.4 - 146.6 kg at randomization and 124.5, CI 105.4 - 143.6 kg at 12 weeks; p = 0.04).

CONCLUSIONS

This pilot study suggests limited efficacy for pioglitazone in the treatment of poorly controlled asthma in obesity, and also the potential for harm, given the weight gain in those assigned to active treatment, and the association between increased weight and worse outcomes in asthma.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT00634036).

Differential Associations between CDH13 Genotypes, Adiponectin Levels, and Circulating Levels of Cellular Adhesive Molecules

CDH13 gene variants with lower adiponectin levels are paradoxically associated with a more favorable metabolic profile. We investigated the statistical association between CDH13 locus variants and adiponectin levels by examining 12 circulating inflammation marker levels and adiposity status in 530 Han Chinese people in Taiwan. After adjustments for clinical covariates, adiponectin levels were positively associated with soluble vascular cell adhesion molecule-1 (sVCAM1) levels and negatively associated with adiposity status and levels of C-reactive protein (CRP), soluble E-selectin (sE-selectin), and soluble intercellular adhesion molecule-1 (sICAM1). In addition, minor alleles of the CDH13 rs12051272 polymorphism were found to have lower adiponectin levels and higher CRP, sE-selectin, sICAM1, and sVCAM1 levels as well as higher body mass indices and waist circumferences in participants (all P < 0.05). In a subgroup analysis stratified by sex, significant associations between CDH13 genotypes and sE-selectin levels occurred only in men (P = 3.9 × 10⁻⁴ and interaction P = 0.005). CDH13 locus variants and adiponectin levels are associated with circulating levels of cellular adhesion molecules and adiposity status in a differential manner that interacts with sex. These results provide further evidence for the crucial role of adiponectin levels and CDH13 gene variants in immune-mediated and inflammatory diseases.

ROCK insufficiency attenuates ozone-induced airway hyperresponsiveness in mice

Ozone causes airway hyperresponsiveness (AHR) and pulmonary inflammation. Rho kinase (ROCK) is a key regulator of smooth muscle cell contraction and inflammatory cell migration. To determine the contribution of the two ROCK isoforms ROCK1 and ROCK2 to ozone-induced AHR, we exposed wild-type, ROCK1(+/-), and ROCK2(+/-) mice to air or ozone (2 ppm for 3 h) and evaluated mice 24 h later. ROCK1 or ROCK2 haploinsufficiency did not affect airway responsiveness in air-exposed mice but significantly reduced ozone-induced AHR, with a greater reduction in ROCK2(+/-) mice despite increased bronchoalveolar lavage (BAL) inflammatory cells in ROCK2(+/-) mice. Compared with wild-type mice, ozone-induced increases in BAL hyaluronan, a matrix protein implicated in ozone-induced AHR, were lower in ROCK1(+/-) but not ROCK2(+/-) mice. Ozone-induced increases in other inflammatory moieties reported to contribute to ozone-induced AHR (IL-17A, osteopontin, TNFα) were not different in wild-type vs. ROCK1(+/-) or ROCK2(+/-) mice. We also observed a dose-dependent reduction in ozone-induced AHR after treatment with the ROCK1/ROCK2 inhibitor fasudil, even though fasudil was administered after induction of inflammation. Ozone increased pulmonary expression of ROCK2 but not ROCK1 or RhoA. A ROCK2 inhibitor, SR3677, reduced contractile forces in primary human airway smooth muscle cells, confirming a role for ROCK2 in airway smooth muscle contraction. Our results demonstrate that ozone-induced AHR requires ROCK. Whereas ROCK1-dependent changes in hyaluronan may contribute to ROCK1's role in O3-induced AHR, the role of ROCK2 is downstream of inflammation, likely at the level of airway smooth muscle contraction.

Obesity and asthma: beyond T(H)2 inflammation

Obesity is a major risk factor for asthma. Likewise, obesity is known to increase disease severity in asthmatic subjects and also to impair the efficacy of first-line treatment medications for asthma, worsening asthma control in obese patients. This concept is in agreement with the current understanding that some asthma phenotypes are not accompanied by detectable inflammation, and may not be ameliorated by classical anti-inflammatory therapy. There are growing evidences suggesting that the obesity-related asthma phenotype does not necessarily involve the classical T(H)2-dependent inflammatory process. Hormones involved in glucose homeostasis and in the pathogeneses of obesity likely directly or indirectly link obesity and asthma through inflammatory and non-inflammatory pathways. Furthermore, the endocrine regulation of the airway-related pre-ganglionic nerves likely contributes to airway hyperreactivity (AHR) in obese states. In this review, we focused our efforts on understanding the mechanism underlying obesity-related asthma by exploring the T(H)2-independent mechanisms leading to this disease.

Modification of the association between PM10 and lung function decline by cadherin 13 polymorphisms in the SAPALDIA cohort: a genome-wide interaction analysis

BACKGROUND

Both air pollution and genetic variation have been shown to affect lung function. Their interaction has not been studied on a genome-wide scale to date.

OBJECTIVES

We aimed to identify, in an agnostic fashion, genes that modify the association between long-term air pollution exposure and annual lung function decline in an adult population-based sample.

METHODS

A two-stage genome-wide interaction study was performed. The discovery (n = 763) and replication (n = 3,896) samples were derived from the multi-center SAPALDIA cohort (Swiss Cohort Study on Air Pollution and Lung Disease in Adults). Annual rate of decline in the forced mid-expiratory flow (FEF25-75%) was the main end point. Multivariate linear regression analyses were used to identify potential multiplicative interactions between genotypes and 11-year cumulative PM10 exposure.

RESULTS

We identified a cluster of variants intronic to the CDH13 gene as the only locus with genome-wide significant interactions. The strongest interaction was observed for rs2325934 (p = 8.8 × 10(-10)). Replication of the interaction between this CDH13 variant and cumulative PM10 exposure on annual decline in FEF25-75% was successful (p = 0.008). The interaction was not sensitive to adjustment for smoking or body weight.

CONCLUSIONS

CDH13 is functionally linked to the adipokine adiponectin, an inflammatory regulator. Future studies need to confirm the interaction and assess how the result relates to previously observed interactions between air pollution and obesity on respiratory function.

Specific metabolic biomarkers as risk and prognostic factors in colorectal cancer

Advances in genomics, molecular pathology and metabolism have generated many candidate biomarkers of colorectal cancer with potential clinical value. Epidemiological and biological studies suggest a role for adiposity, dyslipidaemia, hyperinsulinemia, altered glucose homeostasis, and elevated expression of insulin-like growth factor (IGF) axis members in the risk and prognosis of cancer. This review discusses some recent past and current approaches being taken by researches in obesity and metabolic disorders. The authors describe three main systems as the most studied metabolic candidates of carcinogenesis: dyslipidemias, adipokines and insulin/IGF axis. However, each of these components is unsuccessful in defining the diseases risk and progression, while their co-occurrence increases cancer incidence and mortality in both men and women.

Assembly of adiponectin oligomers

Adiponectin is among the most studied adipokines, the collection of molecules secreted from adipose tissue. It is also one of the most architecturally complex adipokines with its various oligomeric states that include trimers, hexamers, nonamers (9mers), dodecamers (12mers), and octadecamers (18mers). The importance of adiponectin in metabolic regulation is underscored by its strong positive associations with improvement in insulin action and also decreased risks for developing type 2 diabetes. Understanding the mechanisms involved in maintaining the steady-state concentrations of adiponectin oligomers in circulation is therefore likely to provide important insight into the development of insulin resistance. This review will discuss the current state of knowledge regarding the biochemical composition of adiponectin oligomers, the commonly used techniques to analyze them, and the known post-translational modifications that affect their assembly. Evidence based on in vitro oligomer assembly reactions in support of a "cystine ratchet" model of adiponectin oligomer formation will be considered along with limitations of the evidence. Secretory pathway proteins that have been shown to affect the distribution of adiponectin oligomers will also be discussed along with hypotheses regarding their potential involvement in the cystine ratchet model of adiponectin oligomerization.

Scleroderma-related lung disease: are adipokines involved pathogenically?

Scleroderma is a systemic autoimmune disease of unknown etiology whose characteristic features include endothelial cell dysfunction, fibroblast proliferation, and immune dysregulation. Although almost any organ can be pathologically involved in scleroderma, lung complications including interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are the leading cause of death in patients with this condition. Currently, the molecular mechanisms leading to development of scleroderma-related lung disease are poorly understood; however, the systemic nature of this condition has led many to implicate circulating factors in the pathogenesis of some of its organ impairment. In this article we focus on a new class of circulating factors derived from adipose-tissue called adipokines, which are known to be altered in scleroderma. Recently, the adipokines adiponectin and leptin have been found to regulate biological activity in endothelial, fibroblast, and immune cell types in lung and in many other tissues. The pleiotropic nature of these circulating factors and their functional activity on many cell types implicated in the pathogenesis of ILD and PAH suggest these hormones may be mechanistically involved in the onset and/or progression of scleroderma-related lung diseases.

Adiponectin, Leptin, and Resistin in Asthma: Basic Mechanisms through Population Studies

Adipokines, factors produced by adipose tissue, may be proinflammatory (such as leptin and resistin) or anti-inflammatory (such as adiponectin). Effects of these adipokines on the lungs have the potential to evoke or exacerbate asthma. This review summarizes basic mechanistic data through population-based and clinical studies addressing the potential role of adipokines in asthma. Augmenting circulating concentrations of adiponectin attenuates allergic airway inflammation and airway hyperresponsiveness in mice. Murine data is supported by human data that suggest that low serum adiponectin is associated with greater risk for asthma among women and peripubertal girls. Further, higher serum total adiponectin may be associated with lower clinical asthma severity among children and women with asthma. In contrast, exogenous administration of leptin results in augmented allergic airway hyperresponsiveness in mice. Alveolar macrophages obtained from obese asthmatics are uniquely sensitive to leptin in terms of their potential to augment inflammation. Consistent with this basic mechanistic data, epidemiologic studies demonstrate that higher serum leptin is associated with greater asthma prevalence and/or severity and that these associations may be stronger among women, postpubertal girls, and prepubertal boys. The role of adipokines in asthma is still evolving, and it is not currently known whether modulation of adipokines may be helpful in asthma prevention or treatment.

Adiponectin in inflammatory and immune-mediated diseases

Circulating levels of adiponectin (APN) are reduced in obesity and associated comorbidities, with inflammation playing an important role in downregulating APN production. In contrast to obesity and metabolic disease, elevated systemic and local levels of APN are present in patients with inflammatory and immune-mediated diseases, including autoimmune and pulmonary conditions, heart and kidney failure, viral hepatitis, organ transplantation and perhaps critical illness. A positive association between inflammation and APN is usually reported in inflammatory/immune pathologies, in contrast with the negative correlation typical of metabolic disease. This review discusses the role of APN in modulation of inflammation and immunity and the potential mechanisms leading to increased levels of APN in inflammatory/immune diseases, including modification of adipose tissue physiology; relative contribution of different tissues and adipose depots; hormonal, pharmacological, nutritional and life style factors; the potential contribution of the microbiota as well as the role of altered APN clearance and release from T-cadherin-associated tissue reservoirs. Potential reasons for some of the apparently contradictory findings on the role of APN as a modulator of immunity and inflammation are also discussed, including a comparison of types of recombinant APN used for in vitro studies and strain-dependent differences in the phenotype of APN KO mice.

Role of the adiponectin binding protein, T-cadherin (cdh13), in pulmonary responses to subacute ozone

Adiponectin, an adipose derived hormone with pleiotropic functions, binds to several proteins, including T-cadherin. We have previously reported that adiponectin deficient (Adipo(-/-)) mice have increased IL-17A-dependent neutrophil accumulation in their lungs after subacute exposure to ozone (0.3 ppm for 72 hrs). The purpose of this study was to determine whether this anti-inflammatory effect of adiponectin required adiponectin binding to T-cadherin. Wildtype, Adipo(-/-) , T-cadherin deficient (T-cad(-/-) ), and bideficient (Adipo(-/-)/T-cad(-/-) ) mice were exposed to subacute ozone or air. Compared to wildtype mice, ozone-induced increases in pulmonary IL-17A mRNA expression were augmented in T-cad(-/-) and Adipo(-/-) mice. Compared to T-cad(-/-) mice, there was no further increase in IL-17A in Adipo(-/-)/T-cad(-/-) mice, indicating that adiponectin binding to T-cadherin is required for suppression of ozone-induced IL-17A expression. Similar results were obtained for pulmonary mRNA expression of saa3, an acute phase protein capable of inducing IL-17A expression. Comparison of lung histological sections across genotypes also indicated that adiponectin attenuation of ozone-induced inflammatory lesions at bronchiolar branch points required T-cadherin. BAL neutrophils and G-CSF were augmented in T-cad(-/-) mice and further augmented in Adipo(-/-)/T-cad(-/-) mice. Taken together with previous observations indicating that augmentation of these moieties in ozone exposed Adipo(-/-) mice is partially IL-17A dependent, the results indicate that effects of T-cadherin deficiency on BAL neutrophils and G-CSF are likely secondary to changes in IL-17A, but that adiponectin also acts via T-cadherin independent pathways. Our results indicate that T-cadherin is required for the ability of adiponectin to suppress some but not all aspects of ozone-induced pulmonary inflammation.

Impact of adiponectin overexpression on allergic airways responses in mice

Obesity is an important risk factor for asthma. Obese individuals have decreased circulating adiponectin, an adipose-derived hormone with anti-inflammatory properties. We hypothesized that transgenic overexpression of adiponectin would attenuate allergic airways inflammation and mucous hyperplasia in mice. To test this hypothesis, we used mice overexpressing adiponectin (Adipo Tg). Adipo Tg mice had marked increases in both serum adiponectin and bronchoalveolar lavage (BAL) fluid adiponectin. Both acute and chronic ovalbumin (OVA) sensitization and challenge protocols were used. In both protocols, OVA-induced increases in total BAL cells were attenuated in Adipo Tg versus WT mice. In the acute protocol, OVA-induced increases in several IL-13 dependent genes were attenuated in Adipo Tg versus WT mice, even though IL-13 per se was not affected. With chronic exposure, though OVA-induced increases in goblet cells numbers per millimeter of basement membrane were greater in Adipo Tg versus WT mice, mRNA abundance of mucous genes in lungs was not different. Also, adiponectin overexpression did not induce M2 polarization in alveolar macrophages. Our results indicate that adiponectin protects against allergen-induced inflammatory cell recruitment to the airspaces, but not development of goblet cell hyperplasia.