Activation and transforming growth factor-beta production in eosinophils by hyaluronan

Structures, Properties, and Bioengineering Applications of Alginates and Hyaluronic Acid

In recent years, polymeric materials have been used in a wide range of applications in a variety of fields. In particular, in the field of bioengineering, the use of natural biomaterials offers a possible new avenue for the development of products with better biocompatibility, biodegradability, and non-toxicity. This paper reviews the structural and physicochemical properties of alginate and hyaluronic acid, as well as the applications of the modified cross-linked derivatives in tissue engineering and drug delivery. This paper summarizes the application of alginate and hyaluronic acid in bone tissue engineering, wound dressings, and drug carriers. We provide some ideas on how to replace or combine alginate-based composites with hyaluronic-acid-based composites in tissue engineering and drug delivery to achieve better eco-economic value.

Different molecular weights of hyaluronan research in knee osteoarthritis: A state-of-the-art review

Osteoarthritis (OA), the most common form of arthritis, is characterized by progressive cartilage destruction, concomitant adaptive osteogenesis, and loss of joint function. The progression of OA with aging is associated with a decrease in native hyaluronan (HA, hyaluronate or hyaluronic acid) with a high molecular weight (HMW) in synovial fluid and a subsequent increase in lower MW HA and fragments. As HMW HA possesses numerous biochemical and biological properties, we review new molecular insights into the potential of HA to modify OA processes. Different MWs in the formulation of products appear to have varying effects on knee OA (KOA) pain relief, improved function, and postponing surgery. In addition to the safety profile, more evidence indicates that intraarticular (IA) HA administration may be an effective option to treat KOA, with a particular emphasis on the use of HA with fewer injections of higher MW, including potential applications of HA of very HMW. We also analyzed published systemic reviews and meta-analyses of IA HA in treating KOA in order to discuss their conclusions and consensus statements. According to its MW, HA may offer a simple way to refine therapeutic information in selective KOA.

The effects of female sexual hormones on the endothelial glycocalyx

The glycocalyx is a layer composed of carbohydrate side chains bound to core proteins that lines the vascular endothelium. The integrity of the glycocalyx is essential for endothelial cells' performance and vascular homeostasis. The neuroendocrine and immune systems influence the composition, maintenance, activity and degradation of the endothelial glycocalyx. The female organism has unique characteristics, and estrogen and progesterone, the main female hormones are essential to the development and physiology of the reproductive system and to the ability to develop a fetus. Female sex hormones also exert a wide variety of effects on other organs, including the vascular endothelium. They upregulate nitric oxide synthase expression and activity, decrease oxidative stress, increase vasodilation, and protect from vascular injury. This review will discuss how female hormones and pregnancy, which prompts to high levels of estrogen and progesterone, modulate the endothelial glycocalyx. Diseases prevalent in women that alter the glycocalyx, and therapeutic forms to prevent glycocalyx degradation and potential treatments that can reconstitute its structure and function will also be discussed.

Everolimus targeted nanotherapy reduces inflammation and fibrosis in scleroderma-related interstitial lung disease (SSc-ILD) developed by PSGL-1 deficient mice

BACKGROUND AND PURPOSE

Interstitial lung disease (ILD) is the main cause of mortality in systemic sclerosis (SSc) and current therapies available are of low efficacy or high toxicity. Thus, the identification of innovative less toxic and high efficacy therapeutic approaches to ILD treatment is a crucial point. P-selectin Glycoprotein Ligand-1 (PSGL-1) interaction with P-selectin initiates leukocyte extravasation and the lack of its expression brings to SSc-like syndrome with high incidence of ILD in aged mice.

EXPERIMENTAL APPROACH

Aged PSGL-1^-/- mice were used to assay the therapeutic efficacy of an innovative nanotherapy with everolimus (Ev), included in liposomes decorated with high MW hyaluronic acid (LipHA+Ev) and administrated intratracheally to specifically target CD44-expressing lung cells.

KEY RESULTS

PSGL-1^-/- mice had increased number of CD45+ and CD45- cells, including alveolar and interstitial macrophages, eosinophils, granulocytes and NK cells, and elevated number of myofibroblasts in broncoalveolar lavage (BAL). CD45+ and CD45- cells expressing proinflammatory and profibrotic cytokines were also increased. PSGL-1^-/- mice lung histopathology showed increased immune cell infiltration and apoptosis and exacerbated interstitial and peribronchial fibrosis. Targeted nanotherapy with LipHA+Ev reduced BAL number of myofibroblast, cells producing proinflammatory and profibrotic cytokines, and the degree of lung inflammation at histology. LipHA+Ev treatment also provided an important decrease in severity of peribronchial and interstitial lung fibrosis from moderate to mild injury score.

CONCLUSIONS AND IMPLICATIONS

Our preclinical study in PSGL-1^-/- mice indicates that targeted nanotherapy with LipHA+Ev represents an effective treatment for SSc-ILD, reducing the number of inflammatory and fibrotic cells in BAL and reducing inflammation and fibrosis in lungs.

Quantitative assessment of tumor-associated tissue eosinophilia and nuclear organizing region activity to validate the significance of the pattern of invasion in oral squamous cell carcinoma: A retrospective study

Introduction:

Pattern of invasion (POI) in scoring system of oral squamous cell carcinoma (OSCC) can predict local recurrence and overall survival rate. Argyrophilic nucleolar organizer region (AGNOR) counts are considered to reflect the biosynthetic and nucleolar activity of a cell and thus serve as an indicator of the rapidity of the cell cycle thereby indicating the proliferative index of the tumor. It is implied that higher tumor associated tissue eosinophilia (TATE) showed lesser venous invasion, lymph node metastasis and clinical recurrence. The aim of the study was to assess and evaluate the following criteria's: POI-1 to POI-4 as defined by Bryne et al. in OSCC, proliferative index by AgNOR stain and TATE with carbol chromotrope stain in OSCC, validity of POI by correlating the AgNOR proliferative index and TATE.

Materials and Methods:

Forty samples of formalin fixed paraffin embedded tissue blocks diagnosed of OSCC were taken for the study. Three sections were taken from a single block and then the tissues were stained differently with H & E Stain, AgNOR stain and Carbol chromotrope stain. First section stained with H & E was observed for POI and grading was done according to Bryne's criteria. The second and third sections were stained with AgNOR stain and Carbol chromotrope stain for proliferative index and TATE. One way analysis of variance was used to test the significance.

Results:

Mean AgNORs count increases gradually from type 1 to type 4, depicting the increase in the nucleolar proliferative index of the cells and was statistically significant. In the case of the mean eosinophilic count, type 1 shows the highest mean eosinophilic count and the count shows drastic decrease till type 3 and from type 3 to type 4 the decrease is more gradual and was statistically significant.

Conclusion:

The study validated that POI is a good predictor for prognosis and also can be included in grading OSCC along with routine histopathological criteria.

Hyaluronan and Its Receptors as Regulatory Molecules of the Endothelial Interface

On the surface of endothelial cells (ECs) lies the glycocalyx, a barrier of polysaccharides that isolates the ECs from the blood. The role of the glycocalyx is dynamic and complex, thanks to not only its structure, but its vast number of components, one being hyaluronan (HA). HA is a critical component of the glycocalyx, having been found to have a wide variety of functions depending on its molecular weight, its modification, and receptor-ligand interactions. As HA and viscous blood are in constant contact, HA can transmit mechanosensory information directly to the cytoskeleton of the ECs. The degradation and synthesis of HA directly alters the permeability of the EC barrier; HA modulation not only alters the physical barrier but also can signal the initiation of other pathways. EC proliferation and angiogenesis are in part regulated by HA fragmentation, HA-dependent receptor binding, and downstream signals. The interaction between the CD44 receptor and HA is a driving force behind leukocyte recruitment, but each class of leukocyte still interacts with HA in unique ways during inflammation. HA regulates a diverse repertoire of EC functions.

Role of CD44 in breast cancer

Breast cancer (BC) is among the most prevalent type of malignancy affecting females worldwide. BC is classified into different types according to the status of the expression of receptors such as estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), and progesterone receptor (PR). Androgen receptor (AR) appears to be a promising therapeutic target of BC. Binding of 5α-dihydrotestosterone (DHT) to AR controls the expression of microRNA (miRNA) molecules in BC, consequently, affecting protein expression. One of these proteins is the transmembrane glycoprotein cluster of differentiation 44 (CD44). Remarkably, CD44 is a common marker of cancer stem cells in BC. It functions as a co-receptor for a broad diversity of extracellular matrix ligands. Several ligands, primarily hyaluronic acid (HA), can interact with CD44 and mediate its functions. CD44 promotes a variety of functions independently or in cooperation with other cell-surface receptors through activation of varied signaling pathways like Rho GTPases, Ras-MAPK, and PI3K/AKT pathways to regulate cell adhesion, migration, survival, invasion, and epithelial-mesenchymal transition. In this review, we present the relations between AR, miRNA, and CD44 and their roles in BC.

Hyaluronic Acid-Mediated Drug Delivery System Targeting for Inflammatory Skin Diseases: A Mini Review

Hyaluronic acid (HA), a major component of extracellular matrix has been widely applied in pharmaceutical and cosmetic industries due to its reported pharmacological properties. Various types of HA drug delivery system including nanoparticles, cryogel-based formulations, microneedle patches, and nano-emulsions were developed. There are studies reporting that several HA-based transdermal delivery systems exhibit excellent biocompatibility, enhanced permeability and efficient localized release of anti-psoriasis drugs and have shown to inhibit psoriasis-associated skin inflammation. Similarly HA is found in abundant at epidermis of atopic dermatitis (AD) suggesting its role in atopic AD pathology. Anti-allergenic effect of atopic eczema can be achieved through the inhibition of CD44 and protein kinase C alpha (PKCα) interaction by HA. Herein, we aim to evaluate the current innovation on HA drug delivery system and the other potential applications of HA in inflammatory skin diseases, focusing on atopic dermatitis and psoriasis. HA is typically integrated into different delivery systems including nanoparticles, liposomes, ethosomes and microneedle patches in supporting drug penetration through the stratum corneum layer of the skin. For instance, ethosomes and microneedle delivery system such as curcumin-loaded HA-modified ethosomes were developed to enhance skin retention and delivery of curcumin to CD44-expressing psoriatic cells whereas methotrexate-loaded HA-based microneedle was shown to enhance skin penetration of methotrexate to alleviate psoriasis-like skin inflammation. HA-based nanoparticles and pluronic F-127 based dual responsive (pH/temperature) hydrogels had been described to enhance drug permeation through and into the intact skin for AD treatment.

Effect of Prostaglandin D2 on mRNA Expression of Three Isoforms of Hyaluronic Acid Synthase in Nasal Polyp Fibroblasts

BACKGROUND

Hyaluronan is one of the major extracellular matrixes in chronic rhinosinusitis (CRS) associated with tissue remodeling. Prostaglandin D₂ (PGD₂) is also associated with the pathogenesis of CRS. However, little is known about whether PGD₂ regulates hyaluronan production by human airway fibroblasts.

OBJECTIVE

We sought to determine the effect of PGD₂ on the mRNA expression of three isoforms of membrane-bound hyaluronic acid synthase (HAS1, HAS2 and HAS3) in fibroblasts, the major source of hyaluronan production, derived from CRS patients.

METHODS

Nasal polyp-derived fibroblasts (NPDF) and uncinate tissue-derived fibroblasts (UTDF) were established from CRS patients with nasal polyps and those without, respectively. These fibroblasts were stimulated with PGD₂ or PGD₂ receptor (DP/CRTH2)-selective agonists in the presence or absence of receptor-selective antagonists. mRNA levels for HAS1, HAS2 and HAS3 were determined by real-time quantitative PCR.

RESULTS

PGD₂ (1 µM) significantly enhanced HAS1 but not HAS2 or HAS3 mRNA expression by NPDF. Enhanced HAS1 mRNA expression was also obtained by stimulation with a DP receptor-selective agonist, but not with a CRTH2 receptor-selective agonist. In addition, PGD₂-induced HAS1 mRNA expression was significantly inhibited by pre-treatment with DP receptor-selective antagonists. Similar induction of PGD₂-induced HAS1 mRNA expression was seen in UTDF.

CONCLUSION

PGD₂ selectively stimulates HAS1 mRNA expression in local fibroblasts in CRS via DP, but not CRTH2, receptors.

Low Molecular Weight Hyaluronan Induces an Inflammatory Response in Ovarian Stromal Cells and Impairs Gamete Development In Vitro

The ovarian stroma, the microenvironment in which female gametes grow and mature, becomes inflamed and fibrotic with age. Hyaluronan is a major component of the ovarian extracellular matrix (ECM), and in other aging tissues, accumulation of low molecular weight (LMW) hyaluronan fragments can drive inflammation. Thus, we hypothesized that LMW hyaluronan fragments contribute to female reproductive aging by stimulating an inflammatory response in the ovarian stroma and impairing gamete quality. To test this hypothesis, isolated mouse ovarian stromal cells or secondary stage ovarian follicles were treated with physiologically relevant (10 or 100 μg/mL) concentrations of 200 kDa LMW hyaluronan. In ovarian stromal cells, acute LMW hyaluronan exposure, at both doses, resulted in the secretion of a predominantly type 2 (Th2) inflammatory cytokine profile as revealed by a cytokine antibody array of conditioned media. Additional qPCR analyses of ovarian stromal cells demonstrated a notable up-regulation of the eotaxin receptor Ccr3 and activation of genes involved in eosinophil recruitment through the IL5-CCR3 signaling pathway. These findings were consistent with an age-dependent increase in ovarian stromal expression of Ccl11, a major CCR3 ligand. When ovarian follicles were cultured in 10 or 100 μg/mL LMW hyaluronan for 12 days, gametes with compromised morphology and impaired meiotic competence were produced. In the 100 μg/mL condition, LMW hyaluronan induced premature meiotic resumption, ultimately leading to in vitro aging of the resulting eggs. Further, follicles cultured in this LMW hyaluronan concentration produced significantly less estradiol, suggesting compromised granulosa cell function. Taken together, these data demonstrate that bioactive LMW hyaluronan fragments may contribute to reproductive aging by driving an inflammatory stromal milieu, potentially through eosinophils, and by directly compromising gamete quality through impaired granulosa cell function.

Eosinophils in Inflammatory Bowel Disease

Clinical investigations in inflammatory bowel disease (IBD) patients have provided increasing evidence that eosinophils contribute to chronic intestinal inflammation. Accumulation of eosinophils in the gastrointestinal tract correlates with the variations of eosinophil regulatory molecules; however, their role in gastrointestinal dysfunction in IBD has not been fully elucidated. This review will describe the development and characterization of gastrointestinal eosinophils, mechanisms of eosinophil recruitment to the gastrointestinal tract. Moreover, the eosinophil-induced changes to the enteric nervous system associated with disease severity and gastrointestinal dysfunction will be analyzed with suggestive molecular pathways for enteric neuronal injury. Current and potential therapeutic interventions targeting eosinophils will be discussed.

Tissue specific human fibroblast differential expression based on RNAsequencing analysis

Background

Physical forces, such as mechanical stress, are essential for tissue homeostasis and influence gene expression of cells. In particular, the fibroblast has demonstrated sensitivity to extracellular matrices with assumed adaptation upon various mechanical loads. The purpose of this study was to compare the vocal fold fibroblast genotype, known for its unique mechanically stressful tissue environment, with cellular counterparts at various other anatomic locales to identify differences in functional gene expression profiles.

Results

By using RNA-seq technology, we identified differentially expressed gene programs (DEseq2) among seven normal human fibroblast primary cell lines from healthy cadavers, which included: vocal fold, trachea, lung, abdomen, scalp, upper gingiva, and soft palate. Unsupervised gene expression analysis yielded 6216 genes differentially expressed across all anatomic sites. Hierarchical cluster analysis revealed grouping based on anatomic site origin rather than donor, suggesting global fibroblast phenotype heterogeneity. Sex and age-related effects were negligible. Functional enrichment analyses based on separate post-hoc 2-group comparisons revealed several functional themes within the vocal fold fibroblast related to transcription factors for signaling pathways regulating pluripotency of stem cells and extracellular matrix components such as cell signaling, migration, proliferation, and differentiation potential.

Conclusions

Human fibroblasts display a phenomenon of global topographic differentiation, which is maintained in isolation via in vitro assays. Epigenetic mechanical influences on vocal fold tissue may play a role in uniquely modelling and maintaining the local environmental cellular niche during homeostasis with vocal fold fibroblasts distinctly specialized related to their anatomic positional and developmental origins established during embryogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5682-5) contains supplementary material, which is available to authorized users.

Epithelial Expression of an Interstitial Lung Disease-Associated Mutation in Surfactant Protein-C Modulates Recruitment and Activation of Key Myeloid Cell Populations in Mice

Patients with idiopathic pulmonary fibrosis (IPF) often experience precipitous deteriorations, termed "acute exacerbations" (AE), marked by diffuse alveolitis and altered gas exchange, resulting in a significant loss of lung function or mortality. The missense isoleucine to threonine substitution at position 73 (I73T) in the alveolar type 2 cell-restricted surfactant protein-C (SP-C) gene (SFTPC) has been linked to clinical IPF. To better understand the sequence of events that impact AE-IPF, we leveraged a murine model of inducible SP-C^I73T (SP-C^I73T/I73TFlp^+/- ) expression. Following administration of tamoxifen to 8-12-wk-old mice, an upregulation of Sftpc^I73T initiated a diffuse lung injury marked by increases in bronchoalveolar lavage fluid (BALF) protein and histochemical evidence of CD45⁺ and CD11b⁺ cell infiltrates. Flow cytometry of collagenase-digested lung cells revealed a transient, early reduction in SiglecF^hiCD11b^lowCD64^hiCD11c^hi macrophages, countered by the sequential accumulation of SiglecF^loCD11b⁺CD64^-CD11c^-CCR2⁺Ly6C⁺ immature macrophages (3 d), Ly6G⁺ neutrophils (7 d), and SiglecF^hiCD11b^hiCD11c^lo eosinophils (2 wk). By mRNA analysis, BALF cells demonstrated a time-dependent phenotypic shift from a proinflammatory (3 d) to an anti-inflammatory/profibrotic activation state, along with serial elaboration of monocyte and eosinophil recruitment factors. The i.v. administration of clodronate effectively reduced total BALF cell numbers, CCR2⁺ immature macrophages, and eosinophil influx while improving survival. In contrast, resident macrophage depletion from the intratracheal delivery of clodronate liposomes enhanced Sftpc^I73T -induced mortality. These results using Sftpc^I73T mice provide a detailed ontogeny for AE-IPF driven by alveolar epithelial dysfunction that induces a polycellular inflammation initiated by the early influx of proinflammatory CCR2⁺Ly6C^hi immature macrophages.

Regulation of Innate and Adaptive Immunity by TGFβ

Immune regulation by cytokines is crucial in maintaining immune homeostasis, promoting responses to infection, resolving inflammation, and promoting immunological memory. Additionally, cytokine responses drive pathology in immune-mediated disease. A crucial cytokine in the regulation of all aspects of an immune response is transforming growth factor beta (TGFβ). Although best known as a crucial regulator of T cell responses, TGFβ plays a vital role in regulating responses mediated by virtually every innate and adaptive immune cell, including dendritic cells, B cells, NK cells, innate lymphoid cells, and granulocytes. Here, we review our current knowledge of how TGFβ regulates the immune system, highlighting the multifunctional nature of TGFβ and how its function can change depending on location and context of action.

Interplay of extracellular matrix and leukocytes in lung inflammation

During inflammation, leukocytes influx into lung compartments and interact with extracellular matrix (ECM). Two ECM components, versican and hyaluronan, increase in a range of lung diseases. The interaction of leukocytes with these ECM components controls leukocyte retention and accumulation, proliferation, migration, differentiation, and activation as part of the inflammatory phase of lung disease. In addition, bronchial epithelial cells from asthmatic children co-cultured with human lung fibroblasts generate an ECM that is adherent for monocytes/macrophages. Macrophages are present in both early and late lung inflammation. Matrix metalloproteinase 10 (MMP10) is induced in alveolar macrophages with injury and infection and modulates macrophage phenotype and their ability to degrade collagenous ECM components. Collectively, studies outlined in this review highlight the importance of specific ECM components in the regulation of inflammatory events in lung disease. The widespread involvement of these ECM components in the pathogenesis of lung inflammation make them attractive candidates for therapeutic intervention.

Hyaluronic Acid--an "Old" Molecule with "New" Functions: Biosynthesis and Depolymerization of Hyaluronic Acid in Bacteria and Vertebrate Tissues Including during Carcinogenesis

Hyaluronic acid is an evolutionarily ancient molecule commonly found in vertebrate tissues and capsules of some bacteria. Here we review modern data regarding structure, properties, and biological functions of hyaluronic acid in mammals and Streptococcus spp. bacteria. Various aspects of biogenesis and degradation of hyaluronic acid are discussed, biosynthesis and degradation metabolic pathways for glycosaminoglycan together with involved enzymes are described, and vertebrate and bacterial hyaluronan synthase genes are characterized. Special attention is given to the mechanisms underlying the biological action of hyaluronic acid as well as the interaction between polysaccharide and various proteins. In addition, all known signaling pathways involving hyaluronic acid are outlined. Impaired hyaluronic acid metabolism, changes in biopolymer molecular weight, hyaluronidase activity, and enzyme isoforms often accompany carcinogenesis. The interaction between cells and hyaluronic acid from extracellular matrix that may be important during malignant change is discussed. An expected role for high molecular weight hyaluronic acid in resistance of naked mole rat to oncologic diseases and the protective role of hyaluronic acid in bacteria are discussed.

COPD Exacerbations Are Associated With Proinflammatory Degradation of Hyaluronic Acid

BACKGROUND

COPD is characterized by chronic airway inflammation and remodeling, with serious modifications of the extracellular matrix (ECM). Hyaluronic acid (HA) is an abundant ECM molecule in the lung with various biologic functions that depend on its molecular weight (MW). High-MW HA exhibits antiinflammatory and immunosuppressive effects, whereas low-MW HA is proinflammatory. In this study, we investigated whether acute exacerbations of COPD (AECOPDs), which affect patient quality of life and survival, are associated with altered HA turnover in BAL.

METHODS

We used BAL from patients with stable COPD (n = 53) or during AECOPD (n = 44) matched for demographics and clinical characteristics and BAL from control subjects (n = 15). HA, HA synthase-1 (HAS-1), and hyaluronidase (HYAL) values were determined by enzyme-linked immunosorbent assay, and HYAL activity was determined by HA zymography. The MW of HA was analyzed by agarose electrophoresis.

RESULTS

Levels of HA, HAS-1, and HYAL were significantly increased in BAL of patients with stable COPD and during exacerbations compared with control subjects. HYAL activity was significantly increased in BAL of patients with AECOPD, resulting in an increase of low-MW HA during exacerbations. In patients with AECOPD, we also observed a significant negative correlation of HA and HYAL levels with FEV1 % predicted but not with diffusing capacity of lung for carbon monoxide % predicted, indicating that increased HA degradation may be more associated with airway obstruction than with emphysema.

CONCLUSIONS

AECOPDs are associated with increased HYAL activity in BAL and subsequent degradation of HA, which may contribute to airway inflammation and subsequent lung function decline during exacerbations.

Hyaluronan as a therapeutic target in human diseases

Accumulation and turnover of extracellular matrix is a hallmark of tissue injury, repair and remodeling in human diseases. Hyaluronan is a major component of the extracellular matrix and plays an important role in regulating tissue injury and repair, and controlling disease outcomes. The function of hyaluronan depends on its size, location, and interactions with binding partners. While fragmented hyaluronan stimulates the expression of an array of genes by a variety of cell types regulating inflammatory responses and tissue repair, cell surface hyaluronan provides protection against tissue damage from the environment and promotes regeneration and repair. The interactions of hyaluronan and its binding proteins participate in the pathogenesis of many human diseases. Thus, targeting hyaluronan and its interactions with cells and proteins may provide new approaches to developing therapeutics for inflammatory and fibrosing diseases. This review focuses on the role of hyaluronan in biological and pathological processes, and as a potential therapeutic target in human diseases.

Crohn's Disease Fibroblasts Overproduce the Novel Protein KIAA1199 to Create Proinflammatory Hyaluronan Fragments

BACKGROUND & AIMS

Crohn's Disease (CD) is a chronic inflammatory disease of the gastrointestinal tract. Fibrosis, a serious complication of CD, occurs when activated intestinal fibroblasts deposit excessive amounts of extracellular matrix (ECM) in affected areas. A major component of the ECM is high-molecular-weight hyaluronan (HA) that, when depolymerized to low-molecular-weight fragments, becomes proinflammatory and profibrotic. Mechanisms for HA degradation are incompletely understood, but the novel protein KIAA1199 recently was discovered to degrade HA. We hypothesized that KIAA1199 protein is increased in CD colon fibroblasts and generates HA fragments that foster inflammation and fibrosis.

METHODS

Fibroblasts were isolated from explants of surgically resected colon tissue from CD and non-inflammatory bowel disease control (ND) patients. Protein levels and tissue distribution of KIAA1199 were assessed by immunoblot and immunostaining, and functional HA degradation was measured biochemically.

RESULTS

Increased levels of KIAA1199 protein were produced and deposited in the ECM by cultured CD fibroblasts compared with controls. Treatment of fibroblasts with the proinflammatory cytokine interleukin (IL) 6 increased deposition of KIAA1199 in the ECM. CD fibroblasts also produce significantly higher levels of IL6 compared with controls, and antibody blockade of IL6 receptors in CD colon fibroblasts decreased the level of KIAA1199 protein in the ECM. Colon fibroblasts degrade HA, however, small interfering RNA silencing of KIAA1199 abrogated that ability.

CONCLUSIONS

CD fibroblasts produce increased levels of KIAA1199 primarily through an IL6-driven autocrine mechanism. This leads to excessive degradation of HA and the generation of proinflammatory HA fragments, which contributes to maintenance of gut inflammation and fibrosis.

The role of hyaluronan in the pathobiology and treatment of respiratory disease

Hyaluronan, a ubiquitous naturally occurring glycosaminoglycan, is a major component of the extracellular matrix, where it participates in biological processes that include water homeostasis, cell-matrix signaling, tissue healing, inflammation, angiogenesis, and cell proliferation and migration. There are emerging data that hyaluronan and its degradation products have an important role in the pathobiology of the respiratory tract. We review the role of hyaluronan in respiratory diseases and present evidence from published literature and from clinical practice supporting hyaluronan as a novel treatment for respiratory diseases. Preliminary data show that aerosolized exogenous hyaluronan has beneficial activity against airway inflammation, protects against bronchial hyperreactivity and remodeling, and disrupts the biofilm associated with chronic infection. This suggests a role in airway diseases with a predominant inflammatory component such as rhinosinusitis, asthma, chronic obstructive pulmonary disease, cystic fibrosis, and primary ciliary dyskinesia. The potential for hyaluronan to complement conventional therapy will become clearer when data are available from controlled trials in larger patient populations.

Allergic Inflammation in Aspergillus fumigatus-Induced Fungal Asthma

Although fungi are pervasive in many environments, few cause disease in humans. Of these, Aspergillus fumigatus is particularly well suited to be a pathogen of the human lung. Its physical and biological characteristics combine to provide an organism that can cause tremendous morbidity and high mortality if left unchecked. Luckily, that is rarely the case. However, repeated exposure to inhaled A. fumigatus spores often results in an immune response that carries significant immunopathology, exacerbating asthma and changing the structure of the lung with chronic impacts to pulmonary function. This review focuses on the current understanding of the mechanisms that are associated with fungal exposure, sensitization, and infection in asthmatics, as well as the function of various inflammatory cells associated with severe asthma with fungal sensitization.

RNA Seq profiling reveals a novel expression pattern of TGF-β target genes in human blood eosinophils

Despite major advances in our understanding of TGF-β signaling in multiple cell types, little is known about the direct target genes of this pathway in human eosinophils. These cells constitute the major inflammatory component present in the sputum and lung of active asthmatics and their numbers correlate well with disease severity. During the transition from acute to chronic asthma, TGF-β levels rise several fold in the lung which drives fibroblasts to produce extracellular matrix (ECM) and participate in airway and parenchymal remodeling. In this report, we use purified blood eosinophils from healthy donors and analyze baseline and TGF-β responsive genes by RNA Seq, and demonstrate that eosinophils (PBE) express 7981 protein-coding genes of which 178 genes are up-regulated and 199 genes are down-regulated by TGF-β. While 18 target genes have been previously associated with asthma and eosinophilic disorders, the vast majority have been implicated in cell death and survival, differentiation, and cellular function. Ingenuity pathway analysis revealed that 126 canonical pathways are activated by TGF-β including iNOS, TREM1, p53, IL-8 and IL-10 signaling. As TGF-β is an important cytokine for eosinophil function and survival, and pulmonary inflammation and fibrosis, our results represent a significant step toward the identification of novel TGF-β responsive genes and provide a potential therapeutic opportunity by selectively targeting relevant genes and pathways.

Interactions between Hyaluronan and Its Receptors (CD44, RHAMM) Regulate the Activities of Inflammation and Cancer

The glycosaminoglycan hyaluronan (HA), a major component of extracellular matrices, and cell surface receptors of HA have been proposed to have pivotal roles in cell proliferation, migration, and invasion, which are necessary for inflammation and cancer progression. CD44 and receptor for HA-mediated motility (RHAMM) are the two main HA-receptors whose biological functions in human and murine inflammations and tumor cells have been investigated comprehensively. HA was initially considered to be only an inert component of connective tissues, but is now known as a “dynamic” molecule with a constant turnover in many tissues through rapid metabolism that involves HA molecules of various sizes: high molecular weight HA (HMW HA), low molecular weight HA, and oligosaccharides. The intracellular signaling pathways initiated by HA interactions with CD44 and RHAMM that lead to inflammatory and tumorigenic responses are complex. Interestingly, these molecules have dual functions in inflammations and tumorigenesis. For example, the presence of CD44 is involved in initiation of arthritis, while the absence of CD44 by genetic deletion in an arthritis mouse model increases rather than decreases disease severity. Similar dual functions of CD44 exist in initiation and progression of cancer. RHAMM overexpression is most commonly linked to cancer progression, whereas loss of RHAMM is associated with malignant peripheral nerve sheath tumor growth. HA may similarly perform dual functions. An abundance of HMW HA can promote malignant cell proliferation and development of cancer, whereas antagonists to HA-CD44 signaling inhibit tumor cell growth in vitro and in vivo by interfering with HMW HA-CD44 interaction. This review describes the roles of HA interactions with CD44 and RHAMM in inflammatory responses and tumor development/progression, and how therapeutic strategies that block these key inflammatory/tumorigenic processes may be developed in rodent and human diseases.

Hyaluronan stimulates ex vivo B lymphocyte chemotaxis and cytokine production in a murine model of fungal allergic asthma

Allergic asthma is a chronic inflammatory disease of the airways characterized by excessive eosinophilic and lymphocytic inflammation with associated changes in the extracellular matrix (ECM) resulting in airway wall remodeling. Hyaluronan (HA) is a nonsulfated glycosaminoglycan ECM component that functions as a structural cushion in its high molecular mass (HMM) but has been implicated in metastasis and other disease processes when it is degraded to smaller fragments. However, relatively little is known about the role HA in mediating inflammatory responses in allergy and asthma. In the present study, we used a murine Aspergillus fumigatus inhalational model to mimic human disease. After observing in vivo that a robust B cell recruitment followed a massive eosinophilic egress to the lumen of the allergic lung and corresponded with the detection of low molecular mass HA (LMM HA), we examined the effect of HA on B cell chemotaxis and cytokine production in the ex vivo studies. We found that LMM HA functioned through a CD44-mediated mechanism to elicit chemotaxis of B lymphocytes, while high molecular mass HA (HMM HA) had little effect. LMM HA, but not HMM HA, also elicited the production of IL-10 and TGF-β1 in these cells. Taken together, these findings demonstrate a critical role for ECM components in mediating leukocyte migration and function which are critical to the maintenance of allergic inflammatory responses.

Hyaluronan fragments as mediators of inflammation in allergic pulmonary disease

Asthma is frequently caused and/or exacerbated by sensitization to allergens, which are ubiquitous in many indoor and outdoor environments. Severe asthma is characterized by airway hyperresponsiveness and bronchial constriction in response to an inhaled allergen, leading to a disease course that is often very difficult to treat with standard asthma therapies. As a result of interactions among inflammatory cells, structural cells, and the intercellular matrix of the allergic lung, patients with sensitization to allergens may experience a greater degree of tissue injury followed by airway wall remodeling and progressive, accumulated pulmonary dysfunction as part of the disease sequela. In addition, turnover of extracellular matrix (ECM) components is a hallmark of tissue injury and repair. This review focuses on the role of the glycosaminoglycan hyaluronan (HA), a component of the ECM, in pulmonary injury and repair with an emphasis on allergic asthma. Both the synthesis and degradation of the ECM are critical contributors to tissue repair and remodeling. Fragmented HA accumulates during tissue injury and functions in ways distinct from the larger native polymer. There is gathering evidence that HA degradation products are active participants in stimulating the expression of inflammatory genes in a variety of immune cells at the injury site. In this review, we will consider recent advances in the understanding of the mechanisms that are associated with HA accumulation and inflammatory cell recruitment in the asthmatic lung.

Asthmatic airway epithelial cells differentially regulate fibroblast expression of extracellular matrix components

BACKGROUND

Airway remodeling might explain lung function decline among asthmatic children. Extracellular matrix (ECM) deposition by human lung fibroblasts (HLFs) is implicated in airway remodeling. Airway epithelial cell (AEC) signaling might regulate HLF ECM expression.

OBJECTIVES

We sought to determine whether AECs from asthmatic children differentially regulate HLF expression of ECM constituents.

METHODS

Primary AECs were obtained from well-characterized atopic asthmatic (n = 10) and healthy (n = 10) children intubated during anesthesia for an elective surgical procedure. AECs were differentiated at an air-liquid interface for 3 weeks and then cocultured with HLFs from a healthy child for 96 hours. Collagen I (COL1A1), collagen III (COL3A1), hyaluronan synthase (HAS) 2, and fibronectin expression by HLFs and prostaglandin E2 synthase (PGE2S) expression by AECs were assessed by using RT-PCR. TGF-β1 and TGF-β2 concentrations in media were measured by using ELISA.

RESULTS

COL1A1 and COL3A1 expression by HLFs cocultured with AECs from asthmatic patients was greater than that by HLFs cocultured with AECs from healthy subjects (2.2-fold, P < .02; 10.8-fold, P < .02). HAS2 expression by HLFs cocultured with AECs from asthmatic patients was 2.5-fold higher than that by HLFs cocultured with AECs from healthy subjects (P < .002). Fibronectin expression by HLFs cocultured with AECs from asthmatic patients was significantly greater than that by HLFs alone. TGF-β2 activity was increased in cocultures of HLFs with AECs from asthmatic patients (P < .05), whereas PGES2 was downregulated in AEC-HLF cocultures (2.2-fold, P < .006).

CONCLUSIONS

HLFs cocultured with AECs from asthmatic patients showed differential expression of the ECM constituents COL1A1 and COL3A1 and HAS2 compared with HLFs cocultured with AECs from healthy subjects. These findings support a role for altered ECM production in asthmatic airway remodeling, possibly regulated by unbalanced AEC signaling.

J, Losonczy G, Vásárhelyi B, Tamási L. Relationship of circulating hyaluronic acid levels to disease control in asthma and asthmatic pregnancy

Uncontrolled asthma is a risk factor for pregnancy-related complications. Hyaluronic acid (HA), a potential peripheral blood marker of tissue fibrosis in various diseases, promotes eosinophil survival and plays a role in asthmatic airway inflammation as well as in physiological processes necessary to maintain normal pregnancy; however the level of circulating HA in asthma and asthmatic pregnancy is unknown. We investigated HA levels in asthmatic patients (N = 52; asthmatic pregnant (AP) N = 16; asthmatic non-pregnant (ANP) N = 36) and tested their relationship to asthma control. Serum HA level was lower in AP than in ANP patients (27 [24.7-31.55] vs. 37.4 [30.1-66.55] ng/mL, p = 0.006); the difference attenuated to a trend after its adjustment for patients' age (p = 0.056). HA levels and airway resistance were positively (r = 0.467, p = 0.004), HA levels and Asthma Control Test (ACT) total score inversely (r = -0.437, p = 0.01) associated in ANP patients; these relationships remained significant even after their adjustments for age. The potential value of HA in the determination of asthma control was analyzed using ROC analysis which revealed that HA values discriminate patients with ACT total score ≥20 (controlled patients) and <20 (uncontrolled patients) with a 0.826 efficacy (AUC, 95% CI: 0.69-0.97, p = 0.001) when 37.4 ng/mL is used as cut-off value in ANP group, and with 0.78 efficacy (AUC, 95% CI: 0.65-0.92, p = 0.0009) in the whole asthmatic cohort. In conclusion circulating HA might be a marker of asthma control, as it correlates with airway resistance and has good sensitivity in the detection of impaired asthma control. Decrease of HA level in pregnancy may be the consequence of pregnancy induced immune tolerance.

Hyaluronan deposition and co-localization with inflammatory cells and collagen in a murine model of fungal allergic asthma

OBJECTIVE

Allergic asthma is a chronic inflammatory disease of the airways characterized by excessive inflammation and remodeling of the extracellular matrix (ECM) and associated cells of the airway wall. Under inflammatory conditions, hyaluronan (HA), a major component of the ECM, undergoes dynamic changes, which may in turn affect the recruitment and activation of inflammatory cells leading to acute and chronic immunopathology of allergic asthma.

METHODS

In the present study, we measured the changes in HA levels generated at sites of inflammation, and examined its effect on inflammatory responses and collagen deposition in an Aspergillus fumigatus murine inhalational model of allergic asthma.

RESULTS

We found that HA levels are elevated in allergic animals and that the increase correlated with the influx of inflammatory cells 5 days after the second allergen challenge. This increase in HA levels appeared largely due to upregulation of hyaluronidase-1 (HYAL1) and hyaluronidase-2 (HYAL2). Furthermore, HA co-localizes with areas of new collagen synthesis and deposition.

CONCLUSIONS

Overall, our findings contribute to the growing literature that focuses on the components of ECM as inflammatory mediators rather than mere structural support products. The evidence of HA localization in fungal allergic asthma provides the impetus to study HA more closely with allergic leukocytes in murine models. Further studies examining HA's role in mediating cellular responses may help to develop targets for treatment in patients with severe asthma due to fungal sensitization.

CD14+CD33+ myeloid cell-CCL11-eosinophil signature in ulcerative colitis

This study tested the hypothesis that eotaxins (CCL11, CCL24, and CCL26) and IL-5 contribute to eosinophil recruitment to the intestine in UC and that intestinal macrophages are important producers of CCL11 in this disease. Peripheral blood and rectal biopsy samples were obtained from patients with active (n=18) and quiescent UC (n=9), and control patients (n=7). Eosinophil and macrophage levels and activation were analyzed by flow cytometry. Rectal mRNA levels of CCL11, CCL24, CCL26, and IL-5 were determined by qRT-PCR. The cellular source of CCL11 was visualized by immunofluorescence analyses. Eosinophil numbers were elevated in the blood and rectum of active and quiescent UC patients compared with controls. Levels of activated eosinophils (CD66b(high)) correlated with disease severity. Rectal CCL11, CCL24, and CCL26 mRNA levels were increased in active UC, whereas only CCL11 was elevated in quiescent UC. Levels of CCL11, but not CCL24 and CCL26, positively correlated with eosinophil numbers. Numbers of CD14(+)CD33(+) cells correlated with CCL11 and eosinophil levels. Immunofluorescence analyses revealed the presence of CD14(+)CCL11(+) mononuclear cells in colonic biopsies in UC. These results support the hypothesis that CCL11 contributes to eosinophil recruitment in UC and that intestinal myeloid cells are a source of CCL11. Interestingly, rectal levels of CCL24, CCL26, and IL-5 only increase during active UC, coinciding with further elevation of eosinophil numbers and with the activation of rectal eosinophils. In conclusion, there is a link among CD14(+)CD33(+) myeloid cells, CCL11, and eosinophils in adult UC.

Eosinophils in fungus-associated allergic pulmonary disease

Asthma is frequently caused and/or exacerbated by sensitization to fungal allergens, which are ubiquitous in many indoor and outdoor environments. Severe asthma with fungal sensitization is characterized by airway hyperresponsiveness and bronchial constriction in response to an inhaled allergen that is worsened by environmental exposure to airborne fungi and which leads to a disease course that is often very difficult to treat with standard asthma therapies. As a result of complex interactions among inflammatory cells, structural cells, and the intercellular matrix of the allergic lung, patients with sensitization to fungal allergens may experience a greater degree of airway wall remodeling and progressive, accumulated pulmonary dysfunction as part of the disease sequela. From their development in the bone marrow to their recruitment to the lung via chemokine and cytokine networks, eosinophils form an important component of the inflammatory milieu that is associated with this syndrome. Eosinophils are recognized as complex multi-factorial leukocytes with diverse functions in the context of allergic fungal asthma. In this review, we will consider recent advances in our understanding of the molecular mechanisms that are associated with eosinophil development and migration to the allergic lung in response to fungal inhalation, along with the eosinophil’s function in the immune response to and the immunopathology attributed to fungus-associated allergic pulmonary disease.

Eosinophils in infection and intestinal immunity

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBDs, e.g., Crohn's disease and ulcerative colitis) are thought to be a consequence of an uncontrolled inflammatory response against luminal antigens, including commensal bacteria. The observed link between eosinophil levels and severity and remission rates in IBD has led to speculation that eosinophils may contribute to the antimicrobial inflammatory response in IBD.

RECENT FINDINGS

Eosinophils express the necessary cellular machinery (innate immune receptors, proinflammatory cytokines, antibacterial proteins, and DNA traps) to mount an efficient antibacterial response; however, the rapid decline in eosinophil numbers following acute systemic bacterial infection suggests a very limited role for eosinophils in bacterial responses.

SUMMARY

We describe the clinical evidence of eosinophil involvement in IBD, summarize the in-vitro and in-vivo evidence of eosinophil antibacterial activity and the biology of eosinophils focusing on eosinophil-mediated bactericidal mechanisms and the involvement of eosinophil-derived granule proteins in this response, and conceptualize the contribution of eosinophils to a response against commensal bacteria in IBD.

Correlation of hyaluronan deposition with infiltration of eosinophils and lymphocytes in a cockroach-induced murine model of asthma

Asthma is a chronic inflammatory disease that exhibits airway remodeling with changes in the extracellular matrix (ECM). The role of the ECM in mediating these changes is poorly understood. Hyaluronan (HA), a major component of the ECM, has been implicated in many biological processes in diseases. This study investigates the processes involved in HA synthesis, deposition and localization during the propagation of cockroach-induced asthma. Mice were sensitized and challenged with cockroach antigen, and sacrificed at various time points during an 8-week challenge protocol. Analysis of bronchoalveolar lavage (BAL) fluid revealed an increase in total nucleated cells as early as 6h, which peaked at 6 days. Histopathologic analysis of the lung tissue revealed an influx of inflammatory cells at the peribronchial and perivascular regions starting at 12 h, which peaked at 6 days and persisted to 8 weeks. Eosinophils predominated in the early time points while lymphocytes predominated during the late time points. Quantitative polymerase chain reaction (PCR) data showed that hyaluronan synthase 1 (HAS1) mRNA peaked within 6 h and then declined. HAS2 mRNA also peaked within 6 h but remained elevated throughout the 8-week exposure course. HA levels in lung tissue and BAL increased at 12 h and peaked by 6 and 8 days, respectively. Inflammatory cells and new collagen formation localized in areas of HA deposition. Taken together, these data support a role for HA in the pathogenesis in asthma.

Hyaluronan as an immune regulator in human diseases

Accumulation and turnover of extracellular matrix components are the hallmarks of tissue injury. Fragmented hyaluronan stimulates the expression of inflammatory genes by a variety of immune cells at the injury site. Hyaluronan binds to a number of cell surface proteins on various cell types. Hyaluronan fragments signal through both Toll-like receptor (TLR) 4 and TLR2 as well as CD44 to stimulate inflammatory genes in inflammatory cells. Hyaluronan is also present on the cell surface of epithelial cells and provides protection against tissue damage from the environment by interacting with TLR2 and TLR4. Hyaluronan and hyaluronan-binding proteins regulate inflammation, tissue injury, and repair through regulating inflammatory cell recruitment, release of inflammatory cytokines, and cell migration. This review focuses on the role of hyaluronan as an immune regulator in human diseases.

Hyaluronan deposition and correlation with inflammation in a murine ovalbumin model of asthma

Asthma is a chronic inflammatory disease of the airways characterized by airway remodeling, which includes changes in the extracellular matrix (ECM). However the role of the ECM in mediating these changes is poorly understood. Hyaluronan (HA), a major component of the ECM, has been implicated in asthma as well as in many other biological processes. Our study investigates the processes involved in HA synthesis, deposition, localization and degradation during an acute and chronic murine model of ovalbumin (OVA)-induced allergic pulmonary inflammation. Mice were sensitized, challenged to OVA and sacrificed at various time points during an 8-week challenge protocol. Bronchoalveolar lavage (BAL) fluids, blood, and lung tissue were collected for study. RNA, HA, protein and histopathology were analyzed. Analyses of lung sections and BAL fluids revealed an early deposition and an increase in HA levels within 24 h of antigen exposure. HA levels peaked at day 8 in BAL, while inflammatory cell recovery peaked at day 6. Hyaluronan synthase (HAS)1 and HAS2 on RNA levels peaked within 2 h of antigen exposure, while hyaluronidase (HYAL)1 and HYAL2 on RNA levels decreased. Both inflammatory cell infiltrates and collagen deposition co-localized with HA deposition within the lungs. These data support a role for HA in the pathogenesis of inflammation and airway remodeling in a murine model of asthma. HA deposition appears largely due to up regulation of HAS1 and HAS2. In addition, HA appears to provide the scaffolding for inflammatory cell accumulation as well as for new collagen synthesis and deposition.

Nodular basal cell carcinoma is associated with increased hyaluronan homeostasis

BACKGROUND

Basal cell carcinoma (BCC) is one of the most frequent forms of malignancy in humans. Although BCC is a tumour of low degree of malignancy, if left untreated, it can be locally aggressive, eat away at tissues and cause ulceration. Nodular is the most common subtype of BCC (>50%). Although apparently non-invasive, micronodular, a certain subgroup of nodular, is likely to recur. Glycosaminoglycans (GAGs), such as hyaluronic acid (HA), are extracellular matrix molecules of high importance in malignant transformation, metastasis and other complex remodelling processes.

OBJECTIVES

To investigate the expression of GAGs and their metabolizing enzymes in nodular BCC, when compared with adjacent healthy human skin tissue specimens.

METHODS

Total GAGs were isolated and purified from nodular BCC and normal adjacent human skin tissue specimens. GAGs were subsequently fractionated by electrophoresis on cellulose acetate membranes and characterized using specific GAG-degrading enzymes. The content of HA in total GAGs was measured using ELISA and the expression of HA synthases (HAS), hyaluronidases (HYAL) and HA receptors (CD44 and receptor hyaluronic acid-mediated motility (RHAMM) was assessed using RT-PCR.

RESULTS

Nodular BCC is associated with increased levels of HA concomitant with upregulation of gene expression of HAS3, HYAL3 and RHAMM, when compared with normal adjacent skin.

CONCLUSION

These results indicate that HA homeostasis in nodular BCC shows distinct features which may be helpful in understanding the complex behaviour of nodular subtype of BCC, thus eventually leading to new treatment strategies.

Increase effect of transforming growth factor on eotaxin production by normal cultured dermal fibroblasts stimulated with interleukin-4: inhibitory effect of suplatast tosilate on eotaxin production

Eotaxin plays a central role in the development of allergic disease, including atopic dermatitis, asthma, and nasal allergy. Interleukin (IL)-4 induces eotaxin production in normal human dermal fibroblasts. On the other hands, Transforming growth factor-beta (TGF-beta), a multifunctional regulatory cytokine, affects many biological functions, including fibroblast growth and differentiation and Th2 cytokine regulation. In this study, we investigated the effect of TGF-beta on IL-4-induced eotaxin production by normal human fibroblasts, as well as the effect of suplatast tosilate, an antiallergic drug that selectively inhibits Th2 cytokine production. Dermal fibroblast treatment with IL-4 and TGF-beta for 24 h increased eotaxin production and expression of eotaxin mRNA, as measured by enzyme-linked immunosorbent assay (ELISA) and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. TGF-beta synergistically up-regulated eotaxin production and eotaxin mRNA expression when stimulated with IL-4. Suplatast tosilate dose-dependently inhibited eotaxin production induced by IL-4 or IL-4 plus TGF-beta. These results suggest that TGF-beta may regulate skin allergic inflammation by up-regulating eotaxin production in dermal fibroblasts. Suplatast tosilate might suppress this inflammation by inhibiting eotaxin production.

Role of eosinophils and their clinical significance in allergic inflammation

Eosinophils are believed to play roles in the pathophysiology of allergic inflammation, such as bronchial asthma. However, recent studies on anti-interleukin-5 monoclonal antibody treatment of asthmatic patients raised the possibility that eosinophils may play only a limited role. More recent studies established that eosinophils are essentially involved in the development of airway remodeling. Moreover, it is theoretically conceivable that eosinophils are a cellular source of lipid mediators, such as cysteinyl leukotrienes or platelet-activating factor in asthma. Even in the absence of interleukin-5, it is likely that the 'T-helper Type 2 network', including a cascade of vascular cell adhesion molecule-1, intercellular cell adhesion molecule-1, CC chemokines, granulocyte-macrophage colony-stimulating factor, for example, can maintain sufficient eosinophilic infiltration and effector functions, such as superoxide anion generation and degranulation. Long-term studies, wherein tissue eosinophils are eliminated effectively will be required to establish the exact roles of these cells in asthma. Finally, the authors will demonstrate that eosinophils have the potential for not only playing detrimental roles but also beneficial ones.

Deficiency in the serum-derived hyaluronan-associated protein-hyaluronan complex enhances airway hyperresponsiveness in a murine model of asthma

BACKGROUND

Serum-derived hyaluronan (HA)-associated proteins (SHAPs), the heavy chains of inter-α-trypsin inhibitor, covalently bind to HA to form the SHAP-HA complex. The SHAP-HA complex is involved in the pathophysiology of inflammatory diseases, including rheumatoid arthritis. We investigated whether this complex is also involved in airway allergy.

METHODS

SHAP-HA-deficient (bikunin knockout, KO) mice and wild-type (WT) mice were immunized twice by intraperitoneal injection of ovalbumin (OVA) and exposed to aerosol OVA for 30 min each day for 2 weeks. Twenty-four hours after the final OVA challenge, airway responsiveness to inhaled methacholine (MCh) was measured, and analysis of bronchoalveolar lavage fluid (BALF) and lung histological studies were done.

RESULTS

Compared to WT mice, KO mice showed higher airway hyperresponsiveness to inhaled MCh and higher late-phase responses to OVA whereas the early-phase responses were similar. Cell differentials of BALF showed an increased number of macrophages and neutrophils in KO mice. Furthermore, decreased concentrations of soluble tumor necrosis factor receptor-1 (sTNFR1) were found in BALF from KO mice whereas the levels of Th1 and Th2 cytokines were not different from WT mice. Immunochemical study of the lung tissues revealed stronger staining of sTNFR1 in KO than in WT mice.

CONCLUSIONS

Our results suggest that in this murine asthma model, the SHAP-HA complex has an inhibitory role in the development of airway hyperresponsiveness and allergic airway inflammation which may be attributed, at least in part, to negative feedback mechanisms exerted by sTNFR1, the shedding of which from the cell surface might also be promoted by the SHAP-HA complex.

Extrinsic ageing in the human skin is associated with alterations in the expression of hyaluronic acid and its metabolizing enzymes

Extrinsic skin ageing or 'photoageing', as opposed to intrinsic skin ageing, is the result of exposure to external factors, mainly ultraviolet irradiation. Glycosaminoglycans (GAG) and particularly hyaluronic acid (HA) are major components of the cutaneous extracellular matrix involved in tissue repair. However, their involvement in extrinsic skin ageing remains elusive. In this study, we investigated the expression of HA and its metabolizing enzymes in photoexposed and photoprotected human skin tissue specimens, obtained from the same patient. Total GAG were isolated, characterized using specific GAG-degrading enzymes and separated by electrophoresis on cellulose acetate membranes and polyacrylamide gels. Quantitation of HA in total GAG was performed using ELISA. Gene expression of hyaluronan synthases (HAS), hyaluronidases (HYAL) and HA receptors CD44 and receptor for HA-mediated motility (RHAMM) was assessed by RT-PCR. We detected a significant increase in the expression of HA, of lower molecular mass, in photoexposed skin as compared with photoprotected skin. This increase was associated with a significant decrease in the expression of HAS1 and an increase in the expression of HYAL1-3. Furthermore, the expression of HA receptors CD44 and RHAMM was significantly downregulated in photoexposed as compared with photoprotected skin. These findings indicate that extrinsic skin ageing is characterized by distinct homoeostasis of HA. The elucidation of the role of HA homoeostasis in extrinsic skin ageing may offer an additional approach in handling cutaneous ageing.

Hyaluronic acid modulates gene expression of connective tissue growth factor (CTGF), transforming growth factor-beta1 (TGF-beta1), and vascular endothelial growth factor (VEGF) in human fibroblast-like synovial cells from advanced-stage osteoarthritis in vitro

Intraarticular injection of hyaluronan (hyaluronic acid; HA) is the common way to treat osteoarthritis (OA) of knees. This treatment cannot only maintain the viscoelastic properties of knee but also release the OA pain. However, the exact molecular mechanism is unknown. In this study, after human synovial cells were stimulated with HA and Hylan (Synvisc) for 24 h, real-time polymerase chain reaction (real-time PCR) was used to detect the alteration of connective tissue growth factor (CTGF), transforming growth factor-beta1 (TGF-beta1), and vascular endothelial growth factor (VEGF) gene expression, which were specific genes related to pathogenesis of OA knees. Our results illustrated that both HA and Hylan might not cause cytotoxicity or apoptosis of synovial cells in serum deprivation environment. The gene expressions of TGF-beta1 and VEGF were significantly increased at the concentration of 0.1 mg/mL HA and 0.1 mg/mL Hylan, respectively (alpha < 0.05). The synovial cells with treatment of 0.1 mg/mL Hylan decreased the CTGF gene expression (0.66-fold) and VEGF (0.78-fold) compared to 0.1 mg/mL HA (alpha < 0.05). We suggested that the profile of CTGF, TGF-beta1, and VEGF gene expressions in our study might provide the rational mechanism for the therapeutic effect of hyaluronan on OA knees.

Functional role of eosinophils in gastrointestinal inflammation

Eosinophilic gastrointestinal (GI) diseases (EGIDs) are characterized by a rich eosinophilic inflammation of the GI tract. Clinical and experimental studies suggest that eosinophils have a pathogenic role in EGIDs; however, the function of eosinophils in these diseases remains an enigma. This article describes eosinophil immunoregulatory and effector function and discusses the possible involvement of these pathways in EGIDs.

The 'sweet' and 'bitter' involvement of glycosaminoglycans in lung diseases: pharmacotherapeutic relevance

The extracellular matrix (ECM) plays a significant role in the structure and function of the lung. The ECM is a three-dimensional fibre mesh, comprised of various interconnected and intercalated macromolecules, among which are the glycosaminoglycans (GAG). GAG are long, linear and highly charged, heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units (macromolecular sugars) and most of them, as their name implies, have a sweet taste. In the lung, GAG support the structure of the interstitium, the subepithelial tissue and the bronchial walls, and are secreted in the airway secretions. Besides maintaining lung tissue structure, GAG also play an important role in lung function as they regulate hydration and water homeostasis, modulate the inflammatory response and influence lung tissue repair and remodelling. However, depending on their size and/or degree of sulphation, and their immobilization or solubilization in the ECM, specific GAG in the lung either live up to their sweet taste/name, supporting normal lung physiology, or they are associated to 'bitter' effects, related to lung pathology. The present review discusses the biological role of GAG in the lung as well as the involvement of these molecules in various respiratory diseases. Given the great structural diversity of GAG, understanding the changes in GAG expression that occur in lung diseases may lead to novel targets for pharmacological intervention in order to prevent and/or to treat a range of lung diseases.

The role of the extracellular matrix and specific growth factors in the regulation of inflammation and remodelling in asthma

Asthma is a disease characterised by persistent inflammation and structural changes in the airways, referred to as airway remodelling. The mechanisms underlying these processes may be interdependent or they may be separate processes that are driven by common factors. The levels of a variety of growth factors (including transforming growth factor beta, granulocyte macrophage colony stimulating factor, and vascular endothelial growth factor) are known to be changed in the asthmatic airway. These and other growth factors can contribute to the development and persistence of inflammation and remodelling. One of the prominent features of the structural changes of the airways is the increased deposition and alterations in the composition of the extracellular matrix proteins. These proteins include fibronectin, many different collagen types and hyaluronan. There is a dynamic relationship between the extracellular matrix proteins and the airway mesenchymal cells such that the changes in the extracellular matrix proteins can also contribute to the persistence of inflammation and the airway remodelling. This review aims to summarise the role growth factors and extracellular matrix proteins play in the regulation of inflammation and airway remodelling in the asthmatic airway.