Extra-cellular matrix proteins induce matrix metalloproteinase-1 (MMP-1) activity and increase airway smooth muscle contraction in asthma

Association of Matrix Metalloproteinase-1 Promoter Polymorphisms With Asthma Risk

BACKGROUND/AIM

Matrix metalloproteinase-1 (MMP-1) expression has been documented as an influential contributor to the intricate milieu of allergic airway inflammation, tissue remodeling, and the exacerbation of asthma's severity. However, the genetic role underlying MMP-1 in the context of asthma has remained enigmatic, with its full implications yet to be unveiled. Considering this, our research was designed to investigate the association of MMP-1 -1607 rs1799750 and the propensity for asthma severity.

PATIENTS AND METHODS

As a case-control investigation, our study enrolled 198 individuals diagnosed with asthma and age- and sex-matched 453 non-asthmatic controls. The genotypes of MMP-1 rs1799750 were determined utilizing the polymerase chain reaction-restriction fragment length polymorphism methodology.

RESULTS

The frequency distributions of 2G/2G, 1G/2G and 1G/1G genotypes at MMP-1 rs1799750 were 49, 42.9, and 8.1%, respectively, among the patients with asthma. This pattern was not different from that of controls (43.7, 46.8, and 9.5%, respectively) (p for trend=0.4486). The allelic frequency pertaining to the variant 1G allele within the asthma group was 29.5%, with a non-significant disparity compared to the 32.9% in the control group (p=0.2596). Noticeably, there was a positive association between MMP-1 rs1799750 2G/1G and 1G/1G genotypes with asthma severity (p=0.0060).

CONCLUSION

Our research indicated that the presence of MMP-1 rs1799750 1G allele might not be the sole arbiter of an individual's susceptibility to asthma, yet its potential to function as a discerning prognostic marker for the severity of asthma emerged as a noteworthy finding deserving attention and further exploration.

Comparing Effects of Short- and Long-Term Exposure of Cigarette Smoke Extract on Human Vocal Fold Fibroblasts

OBJECTIVES

To explore the effects of short- and long-term cigarette smoke extract (CSE) stimulation on the expression of extracellular matrix (ECM) components and inflammatory cytokines in an in vitro model for studying Reinke's edema using human vocal fold fibroblasts (hVFF).

STUDY DESIGN

Experimental pilot study using intervention with CSE in vitro.

METHODS

Immortalized hVFF were pretreated with 5% CSE or control medium over a period of 2 or 8 weeks, followed by a final 3-day incubation time. We evaluated cell proliferation and examined gene and protein expression of control- and CSE-treated cells using quantitative polymerase chain reaction, Western Blot and enzyme linked immunosorbent assay.

RESULTS

Cell numbers of CSE-treated hVFF strongly decreased after 8 weeks and limited the overall duration of the experiment. We observed significant upregulations in gene expression and protein levels of inflammatory markers (cyclooxygenase COX1, COX2) and ECM components (decorin, matrix metalloproteinase 1, transglutaminase 2, gremlin 2) induced by CSE after 2 and 8 weeks. Interleukin 1 receptor 1, prostaglandin I2 synthase, collagen- and hyaluronan-related gene expression showed minor upregulations. The majority of the observed genes were similarly regulated at both time points. However, the CSE-induced mRNA level of COX1 was ablated after 8 weeks.

CONCLUSION

Long-term treatment did not yield results significantly different from the short-term protocol. Therefore, we propose that prolonged CSE exposure is not superior to short-term settings, which save both time and materials.

A tri-layer decellularized, dehydrated human amniotic membrane scaffold supports the cellular functions of human tenocytes in vitro

Differences in scaffold design have the potential to influence cell-scaffold interactions. This study sought to determine whether a tri-layer design influences the cellular function of human tenocytes in vitro. The single-layer decellularized, dehydrated human amniotic membrane (DDHAM) and the tri-layer DDHAM (DDHAM-3L) similarly supported tenocyte function as evidenced by improved cell growth and migration, reduced dedifferentiation, and an attenuated inflammatory response. The tri-layer design provides a mechanically more robust scaffold without altering biological activity.

Cytokine profile in childhood asthma

Childhood asthma is a chronic airway disease, which pathogenesis is markedly heterogeneous–with multiple phenotypes defining visible characteristics and endotypes defining molecular mechanisms. Cytokines and chemokines released during inflammatory responses are key immune mediators. The cytokine response can largely determine the susceptibility to childhood asthma and its severity. The purpose of this study was to characterize the immune profile of childhood asthma. The study involved 26 children (3–18 years old), who were divided into 2 groups: study–with childhood asthma; control–without asthma. The innovative Bio-Plex method was used to determine the serum concentration of 37 inflammatory proteins in one experiment. The results were analyzed using univariate statistical tests. In the study group, the level of the 10 tested markers increased, while the level of the remaining 9 decreased compared to the control; a statistically significant reduction in concentration was obtained only for the MMP-1(p<0.05). According to the ROC curve, MMP-1 can be considered an effective discriminator of childhood asthma (p<0.05; AUC=0.752). Cytokines/chemokines may be useful in the diagnosis of childhood asthma and may also become a prognostic target in determining the phenotype/endotype of this condition. This study should be a prelude to and an incentive for more complex proteomic analyzes.

Hedgehog Signaling: Linking Embryonic Lung Development and Asthmatic Airway Remodeling

The development of the embryonic lung demands complex endodermal–mesodermal interactions, which are regulated by a variety of signaling proteins. Hedgehog (Hh) signaling is vital for lung development. It plays a key regulatory role during several morphogenic mechanisms, such as cell growth, differentiation, migration, and persistence of cells. On the other hand, abnormal expression or loss of regulation of Hh signaling leads to airway asthmatic remodeling, which is characterized by cellular matrix modification in the respiratory system, goblet cell hyperplasia, deposition of collagen, epithelial cell apoptosis, proliferation, and activation of fibroblasts. Hh also targets some of the pathogens and seems to have a significant function in tissue repairment and immune-related disorders. Similarly, aberrant Hh signaling expression is critically associated with the etiology of a variety of other airway lung diseases, mainly, bronchial or tissue fibrosis, lung cancer, and pulmonary arterial hypertension, suggesting that controlled regulation of Hh signaling is crucial to retain healthy lung functioning. Moreover, shreds of evidence imply that the Hh signaling pathway links to lung organogenesis and asthmatic airway remodeling. Here, we compiled all up-to-date investigations linked with the role of Hh signaling in the development of lungs as well as the attribution of Hh signaling in impairment of lung expansion, airway remodeling, and immune response. In addition, we included all current investigational and therapeutic approaches to treat airway asthmatic remodeling and immune system pathway diseases.

Asthmatic Eosinophils Alter the Gene Expression of Extracellular Matrix Proteins in Airway Smooth Muscle Cells and Pulmonary Fibroblasts

The impaired production of extracellular matrix (ECM) proteins by airway smooth muscle cells (ASMC) and pulmonary fibroblasts (PF) is a part of airway remodeling in asthma. This process might be influenced by eosinophils that migrate to the airway and abundantly secrete various cytokines, including TGF-β. We aimed to investigate the effect of asthmatic eosinophils on the gene expression of ECM proteins in ASMC and PF. A total of 34 study subjects were recruited: 14 with allergic asthma (AA), 9 with severe non-allergic eosinophilic asthma (SNEA), and 11 healthy subjects (HS). All AA patients underwent bronchial allergen challenge with D. pteronyssinus. The peripheral blood eosinophils were isolated using high-density centrifugation and magnetic separation. The individual cell cultures were made using hTERT ASMC and MRC-5 cell lines and the subjects’ eosinophils. The gene expression of ECM and the TGF-β signaling pathway was analyzed using qRT-PCR. We found that asthmatic eosinophils significantly promoted collagen I, fibronectin, versican, tenascin C, decorin, vitronectin, periostin, vimentin, MMP-9, ADAM33, TIMP-1, and TIMP-2 gene expression in ASMC and collagen I, collagen III, fibronectin, elastin, decorin, MMP-2, and TIMP-2 gene expression in PF compared with the HS eosinophil effect. The asthmatic eosinophils significantly increased the gene expression of several canonical and non-canonical TGF-β signaling pathway components in ASMC and PF compared with the HS eosinophil effect. The allergen-activated AA and SNEA eosinophils had a greater effect on these changes. In conclusion, asthmatic eosinophils, especially SNEA and allergen-activated eosinophils, imbalanced the gene expression of ECM proteins and their degradation-regulating proteins. These changes were associated with increased gene expression of TGF-β signaling pathway molecules in ASMC and PF.

Serum Proteomic Profile of Asthmatic Patients after Six Months of Benralizumab and Mepolizumab Treatment

Severe eosinophilic asthma is characterized by chronic airway inflammation, oxidative stress, and elevated proinflammatory cytokines, especially IL-5. Mepolizumab and benralizumab are both humanized IgG antibodies directed against IL-5 signaling, directly acting on eosinophils count. Together with the complexity of severe asthma classification and patient selection for the targeted treatment, there is also the urgency to clarify the follow-up of therapy to identify biomarkers, in addition to eosinophils, for the optimal duration of treatment, persistence of effectiveness, and safety. To this purpose, here we performed a follow-up study using differential proteomic analysis on serum samples after 1 and 6 months of both therapies and sera from healthy patients. Statistical analysis by PCA and heatmap analyses were performed, and identified proteins were used for enrichment analysis by MetaCore software. The analysis highlighted 82 differences among all considered conditions. In particular, 30 referred to benralizumab time point (T0, T1B, T6B) and 24 to mepolizumab time point (T0, T1M, T6M) analyses. t-SNE and heatmap analyses evidence that the differential serum protein profile at 6 months of both treatments is more similar to that of the healthy subjects. Among the identified proteins, APOAI, APOC-II, and APOC-III are upregulated principally after 6 months of benralizumab treatment, plasminogen is upregulated after 6 months of both treatments and ceruloplasmin, upregulated already after 1 month of benralizumab, becoming higher after 6 months of mepolizumab. Using enrichment analysis, identified proteins were related to lipid metabolism and transport, blood coagulation, and ECM remodeling.

Matrix Metalloproteinases Inhibition by Doxycycline Rescues Extracellular Matrix Organization and Partly Reverts Myofibroblast Differentiation in Hypermobile Ehlers-Danlos Syndrome Dermal Fibroblasts: A Potential Therapeutic Target?

Hypermobile Ehlers-Danlos syndrome (hEDS) is the most frequent type of EDS and is characterized by generalized joint hypermobility and musculoskeletal manifestations which are associated with chronic pain, and mild skin involvement along with the presence of more than a few comorbid conditions. Despite numerous research efforts, no causative gene(s) or validated biomarkers have been identified and insights into the disease-causing mechanisms remain scarce. Variability in the spectrum and severity of symptoms and progression of hEDS patients’ phenotype likely depend on a combination of age, gender, lifestyle, and the probable multitude of genes involved in hEDS. However, considering the clinical overlap with other EDS forms, which lead to abnormalities in extracellular matrix (ECM), it is plausible that the mechanisms underlying hEDS pathogenesis also affect the ECM to a certain extent. Herein, we performed a series of in vitro studies on the secretome of hEDS dermal fibroblasts that revealed a matrix metalloproteinases (MMPs) dysfunction as one of the major disease drivers by causing a detrimental feedback loop of excessive ECM degradation coupled with myofibroblast differentiation. We demonstrated that doxycycline-mediated inhibition of MMPs rescues in hEDS cells a control-like ECM organization and induces a partial reversal of their myofibroblast-like features, thus offering encouraging clues for translational studies confirming MMPs as a potential therapeutic target in hEDS with the expectation to improve patients’ quality of life and alleviate their disabilities.

Effects of Tenascin C on the Integrity of Extracellular Matrix and Skin Aging

Tenascin C (TNC) is an element of the extracellular matrix (ECM) of various tissues, including the skin, and is involved in modulating ECM integrity and cell physiology. Although skin aging is apparently associated with changes in the ECM, little is known about the role of TNC in skin aging. In this study, we found that the Tnc mRNA level was significantly reduced in the skin tissues of aged mice compared with young mice, consistent with reduced TNC protein expression in aged human skin. TNC-large (TNC-L; 330-kDa) and -small (TNC-S; 240-kDa) polypeptides were observed in conditional media from primary dermal fibroblasts. Both recombinant TNC polypeptides, corresponding to TNC-L and TNC-S, increased the expression of type I collagen and reduced the expression of matrix metalloproteinase-1 in fibroblasts. Treatment of fibroblasts with a recombinant TNC polypeptide, corresponding to TNC-L, induced phosphorylation of SMAD2 and SMAD3. TNC increased the level of transforming growth factor-β1 (TGF-β1) mRNA and upregulated the expression of type I collagen by activating the TGF-β signaling pathway. In addition, TNC also promoted the expression of type I collagen in fibroblasts embedded in a three-dimensional collagen matrix. Our findings suggest that TNC contributes to the integrity of ECM in young skin and to prevention of skin aging.

Genomics of asthma, allergy and chronic rhinosinusitis: novel concepts and relevance in airway mucosa

Genome wide association studies (GWASs) have revealed several airway disease-associated risk loci. Their role in the onset of asthma, allergic rhinitis (AR) or chronic rhinosinusitis (CRS), however, is not yet fully understood. The aim of this review is to evaluate the airway relevance of loci and genes identified in GWAS studies. GWASs were searched from databases, and a list of loci associating significantly (p < 10-8) with asthma, AR and CRS was created. This yielded a total of 267 significantly asthma/AR-associated loci from 31 GWASs. No significant CRS -associated loci were found in this search. A total of 170 protein coding genes were connected to these loci. Of these, 76/170 (44%) showed bronchial epithelial protein expression in stained microscopic figures of Human Protein Atlas (HPA), and 61/170 (36%) had a literature report of having airway epithelial function. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation analyses were performed, and 19 functional protein categories were found as significantly (p < 0.05) enriched among these genes. These were related to cytokine production, cell activation and adaptive immune response, and all were strongly connected in network analysis. We also identified 15 protein pathways that were significantly (p < 0.05) enriched in these genes, related to T-helper cell differentiation, virus infection, JAK-STAT signaling pathway, and asthma. A third of GWAS-level risk loci genes of asthma or AR seemed to have airway epithelial functions according to our database and literature searches. In addition, many of the risk loci genes were immunity related. Some risk loci genes also related to metabolism, neuro-musculoskeletal or other functions. Functions overlapped and formed a strong network in our pathway analyses and are worth future studies of biomarker and therapeutics.

Tunable bioactivity and mechanics of collagen-based tissue engineering constructs: A comparison of EDC-NHS, genipin and TG2 crosslinkers

Due to its ubiquity and versatility in the human body, collagen is an ideal base material for tissue-engineering constructs. Chemical crosslinking treatments allow precise control of the biochemical and mechanical properties through macromolecular modifications to the structure of collagen. In this work, three key facets regarding the collagen crosslinking process are explored. Firstly, a comparison is drawn between the carbodiimide-succinimide (EDC-NHS) system and two emerging crosslinkers utilising alternate chemistries: genipin and tissue transglutaminase (TG2). By characterising the chemical changes upon treatment, the effect of EDC-NHS, genipin and TG2 crosslinking mechanisms on the chemical structure of collagen, and thus the mechanical properties conferred to the substrate is explored. Secondly, the relative importance of mechanical and biochemical cues on cellular phenomena are investigated, including cell viability, integrin-specific attachment, spreading and proliferation. Here, we observe that for human dermal fibroblasts, long-term, stable proliferation is preconditioned by the availability of suitable binding sites, irrespective of the substrate modulus post-crosslinking. Finally, as seen in the graphical abstract we show that by choosing the appropriate crosslinker chemistries, a materials selection map can be drawn for collagen films, encompassing both a range of tensile modulus and fibroblast proliferation which can be modified independently. Thus, in addition to a range of parameters that can be modified in collagen constructs, we demonstrate a route to obtaining tunable bioactivity and mechanics in collagen constructs is uncovered, that is exclusively driven by the crosslinking process.

Sustained exposure to prostaglandin D2 augments the contraction induced by acetylcholine via a DP1 receptor-mediated activation of p38 in bronchial smooth muscle of naive mice

Prostaglandin D₂ (PGD₂), one of the key lipid mediators of allergic airway inflammation, is increased in the airways of asthmatics. However, the role of PGD₂ in the pathogenesis of asthma is not fully understood. In the present study, effects of PGD₂ on smooth muscle contractility of the airways were determined to elucidate its role in the development of airway hyperresponsiveness (AHR). In a murine model of allergic asthma, antigen challenge to the sensitized animals caused a sustained increase in PGD₂ levels in bronchoalveolar lavage (BAL) fluids, indicating that smooth muscle cells of the airways are continually exposed to PGD₂ after the antigen exposure. In bronchial smooth muscles (BSMs) isolated from naive mice, a prolonged incubation with PGD₂ (10⁻⁵ M, for 24 h) induced an augmentation of contraction induced by acetylcholine (ACh): the ACh concentration-response curve was significantly shifted upward by the 24-h incubation with PGD₂. Application of PGD₂ caused phosphorylation of ERK1/2 and p38 in cultured BSM cells: both of the PGD₂-induced events were abolished by laropiprant (a DP₁ receptor antagonist) but not by fevipiprant (a DP₂ receptor antagonist). In addition, the BSM hyperresponsiveness to ACh induced by the 24-h incubation with PGD₂ was significantly inhibited by co-incubation with SB203580 (a p38 inhibitor), whereas U0126 (a ERK1/2 inhibitor) had no effect on it. These findings suggest that prolonged exposure to PGD₂ causes the BSM hyperresponsiveness via the DP₁ receptor-mediated activation of p38. A sustained increase in PGD₂ in the airways might be a cause of the AHR in allergic asthmatics.

Asthma and Lung Mechanics

This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.

Tunable bioactivity and mechanics of collagen-based tissue engineering constructs: A comparison of EDC-NHS, genipin and TG2 crosslinkers

Due to its ubiquity and versatility in the human body, collagen is an ideal base material for tissue-engineering constructs. Chemical crosslinking treatments allow precise control of the biochemical and mechanical properties through macromolecular modifications to the structure of collagen. In this work, three key facets regarding the collagen crosslinking process are explored. Firstly, a comparison is drawn between the carbodiimide-succinimide (EDC-NHS) system and two emerging crosslinkers utilising alternate chemistries: genipin and tissue transglutaminase (TG2). By characterising the chemical changes upon treatment, the effect of EDC-NHS, genipin and TG2 crosslinking mechanisms on the chemical structure of collagen, and thus the mechanical properties conferred to the substrate is explored. Secondly, the relative importance of mechanical and biochemical cues on cellular phenomena are investigated, including cell viability, integrin-specific attachment, spreading and proliferation. Here, we observe that for human dermal fibroblasts, long-term, stable proliferation is preconditioned by the availability of suitable binding sites, irrespective of the substrate modulus post-crosslinking. Finally, as seen in the graphical abstract we show that by choosing the appropriate crosslinker chemistries, a materials selection map can be drawn for collagen films, encompassing both a range of tensile modulus and fibroblast proliferation which can be modified independently. Thus, in addition to a range of parameters that can be modified in collagen constructs, we demonstrate a route to obtaining tunable bioactivity and mechanics in collagen constructs is uncovered, that is exclusively driven by the crosslinking process.

Mast Cell-Mediated Orchestration of the Immune Responses in Human Allergic Asthma: Current Insights

Improving the lung function after experimental allergen challenge by blocking of mast cell (MC) mediators and the capability of MC mediators (including histamine, prostaglandin (PG) D2, and leukotriene (LT) C4) in induction of mucosal edema, bronchoconstriction, and mucus secretion provide evidence that MCs play a key role in pathophysiology of asthma. In asthma, the number of MCs increases in the airways and infiltration of MCs in a variety of anatomical sites including the epithelium, the submucosal glands, and the smooth muscle bundles occurs. MC localization within the ASM is accompanied with the hypertrophy and hyperplasia of the layer, and smooth muscle dysfunction that is mainly observed in forms of bronchial hyperresponsiveness, and variable airflow obstruction. Owing to the expression of a wide range of surface receptors and releasing various cytoplasmic mediators, MCs orchestrate the pathologic events of the disease. MC-released preformed mediators including chymase, tryptase, and histamine and de novo synthesized mediators such as PGD2, LTC4, and LTE4 in addition of cytokines mainly TGFβ1, TSLP, IL-33, IL-4, and IL-13 participate in pathogenesis of asthma. The release of MC mediators and MC/airway cell interactions during remodeling phase of asthma results in persistent cellular and structural changes in the airway wall mainly epithelial cell shedding, goblet cell hyperplasia, hypertrophy of ASM bundles, fibrosis in subepithelial region, abnormal deposition of extracellular matrix (ECM), increased tissue vascularity, and basement membrane thickening. We will review the current knowledge regarding the participation of MCs in each stage of asthma pathophysiology including the releasing mediators and their mechanism of action, expression of receptors by which they respond to stimuli, and finally the pharmaceutical products designed based on the strategy of blocking MC activation and mediator release.

Characterization of a subgroup of non-type 2 asthma with cow's milk hypersensitivity in young subjects

Background

Asthma with atopy is often characterized by type 2 inflammation but less progress has been made in defining non-type 2 asthma. We have previously identified a subgroup of young non-atopic asthmatics with perceived food hypersensitivity and poor asthma control.

Objective

Our aim was to further characterize this subgroup of non-type 2 asthmatics, including the use of a broad panel of inflammation-related proteins.

Methods

Sex- and age-matched subjects (10–35 years old) were divided into three groups with regard to history of asthma and atopy: non-atopic asthmatics with perceived cow’s milk hypersensitivity but with IgE antibodies < 0.35 kU_A/L (NAA; n = 24), non-atopic controls with IgE < 0.35 kU_A/L (NAC; n = 24), and atopic asthmatics with IgE ≥ 0.35 kU_A/L (AA; n = 29). Serum or plasma were analysed using the multi-allergen tests Phadiatop and fx5 (ImmunoCAP), a multiplex immunoassay comprising 92 inflammation-related proteins (Proseek Inflammation), and an ELISA for human neutrophil lipocalin (S-HNL). Fraction of exhaled nitric oxide (FeNO), blood eosinophil (B-Eos) count, C-reactive protein (CRP), airway responsiveness to methacholine (PD₂₀), and asthma-related quality of life (mAQLQ) were also measured.

Results

NAA had lower FeNO (p < 0.001) and B-Eos count (p < 0.001), but scored worse on mAQLQ (p = 0.045) compared with AA. NAA displayed higher levels of matrix metalloproteinase-1 (MMP-1) compared with both NAC (p = 0.011) and AA (p = 0.001), and lower PD₂₀ compared with NAC (p < 0.001). In NAA, S-HNL correlated negatively with PD₂₀ (rho = − 0.048, p < 0.05) and CRP correlated negatively with mAQLQ (rho = − 0.439, p < 0.05).

Conclusion

In a subgroup of non-atopic young asthmatics with perceived cow’s milk hypersensitivity we observed poor asthma-related quality of life, airway hyperresponsiveness, and clinically relevant non-type 2 inflammation. MMP-1 was elevated in this group, which deserves further studies.

Electronic supplementary material

The online version of this article (10.1186/s13601-019-0250-2) contains supplementary material, which is available to authorized users.

German Cockroach Extract Induces Matrix Metalloproteinase-1 Expression, Leading to Tight Junction Disruption in Human Airway Epithelial Cells

PURPOSE

Cockroach exposure is a pivotal cause of asthma. Tight junctions are intercellular structures required for maintenance of the barrier function of the airway epithelium, which is impaired in this disease. Matrix metalloproteinases (MMPs) digest extracellular matrix components and are involved in asthma pathogenesis: MMP1 is a collagenase with a direct influence on airway obstruction in asthmatics. This study aimed to investigate the mechanism by which German cockroach extract (GCE) induces MMP1 expression and whether MMP1 release alters cellular tight junctions in human airway epithelial cells (NCI-H292).

MATERIALS AND METHODS

mRNA and protein levels were determined using real-time PCR and ELISA. Tight junction proteins were detected using immunofluorescence staining. Epithelial barrier function was measured by transepithelial electrical resistance (TEER). The binding of a transcription factor to DNA molecules was determined by electrophoretic mobility shift assay, while the levels of tight junction proteins and phosphorylation were determined using Western blotting.

RESULTS

GCE was shown to increase MMP1 expression, TEER, and tight junction degradation. Both an inhibitor and small interfering RNA (siRNA) of MMP1 significantly decreased GCE-induced tight junction disruption. Furthermore, transient transfection with ETS1 and SP1 siRNA, and anti-TLR2 antibody pretreatment prevented MMP1 expression and tight junction degradation. An extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) inhibitor also blocked MMP1 release, ETS1/SP1 DNA binding, and tight junction alteration.

CONCLUSION

GCE treatment increases MMP1 expression, leading to tight junction disruption, which is transcriptionally regulated and influenced by the ERK/MAPK pathway in airway epithelial cells. These findings may contribute to developing novel therapeutic strategies for airway diseases.

Fibroblast-to-myofibroblast transition in bronchial asthma

Bronchial asthma is a chronic inflammatory disease in which bronchial wall remodelling plays a significant role. This phenomenon is related to enhanced proliferation of airway smooth muscle cells, elevated extracellular matrix protein secretion and an increased number of myofibroblasts. Phenotypic fibroblast-to-myofibroblast transition represents one of the primary mechanisms by which myofibroblasts arise in fibrotic lung tissue. Fibroblast-to-myofibroblast transition requires a combination of several types of factors, the most important of which are divided into humoural and mechanical factors, as well as certain extracellular matrix proteins. Despite intensive research on the nature of this process, its underlying mechanisms during bronchial airway wall remodelling in asthma are not yet fully clarified. This review focuses on what is known about the nature of fibroblast-to-myofibroblast transition in asthma. We aim to consider possible mechanisms and conditions that may play an important role in fibroblast-to-myofibroblast transition but have not yet been discussed in this context. Recent studies have shown that some inherent and previously undescribed features of fibroblasts can also play a significant role in fibroblast-to-myofibroblast transition. Differences observed between asthmatic and non-asthmatic bronchial fibroblasts (e.g., response to transforming growth factor β, cell shape, elasticity, and protein expression profile) may have a crucial influence on this phenomenon. An accurate understanding and recognition of all factors affecting fibroblast-to-myofibroblast transition might provide an opportunity to discover efficient methods of counteracting this phenomenon.

Integrin α2β1 Expression Regulates Matrix Metalloproteinase-1-Dependent Bronchial Epithelial Repair in Pulmonary Tuberculosis

Pulmonary tuberculosis (TB) is caused by inhalation of Mycobacterium tuberculosis, which damages the bronchial epithelial barrier to establish local infection. Matrix metalloproteinase-1 plays a crucial role in the immunopathology of TB, causing breakdown of type I collagen and cavitation, but this collagenase is also potentially involved in bronchial epithelial repair. We hypothesized that the extracellular matrix (ECM) modulates M. tuberculosis-driven matrix metalloproteinase-1 expression by human bronchial epithelial cells (HBECs), regulating respiratory epithelial cell migration and repair. Medium from monocytes stimulated with M. tuberculosis induced collagenase activity in bronchial epithelial cells, which was reduced by ~87% when cells were cultured on a type I collagen matrix. Matrix metalloproteinase-1 had a focal localization, which is consistent with cell migration, and overall secretion decreased by 32% on type I collagen. There were no associated changes in the specific tissue inhibitors of metalloproteinases. Decreased matrix metalloproteinase-1 secretion was due to ligand-binding to the α2β1 integrin and was dependent on the actin cytoskeleton. In lung biopsies, samples from patients with pulmonary TB, integrin α2β1 is highly expressed on the bronchial epithelium. Areas of lung with disrupted collagen matrix showed an increase in matrix metalloproteinases-1 expression compared with areas where collagen was comparable to control lung. Type I collagen matrix increased respiratory epithelial cell migration in a wound-healing assay, and this too was matrix metalloproteinase-dependent, since it was blocked by the matrix metalloproteinase inhibitor GM6001. In summary, we report a novel mechanism by which α2β1-mediated signals from the ECM modulate matrix metalloproteinase-1 secretion by HBECs, regulating their migration and epithelial repair in TB.

Casticin inhibits PDGF-induced proliferation and migration of airway smooth muscle cells

Casticin (3', 5-dihydroxy-3, 4', 6, 7-tetramethoxyflavone), one of the main components from Vitex rotundifolia L., was reported to possess several pharmacological properties, including anti-inflammatory, hepatoprotective, anticancer, anti-asthma activities. However, the effects of casticin on airway smooth muscle cells (ASMCs) proliferation and migration have not been explored. This study aimed to evaluate the effects of casticin on the proliferation and migration of ASMCs, and study the possible molecular mechanism. Our results demonstrated that casticin significantly suppressed the proliferation and migration of ASMCs exposed to platelet-derived growth factor (PDGF), as well as reversed the PDGF-induced inhibition of the expression of contractile phenotype markers in ASMCs. In addition, casticin also inhibited PDGF-induced the expression of type I collagen and fibronectin in ASMCs induced by PDGF. Furthermore, casticin significantly prevented the activation of ERK1/2 and NF-κB pathways in PDGF-stimulated ASMCs. Taken together, these data demonstrated that casticin inhibits PDGF-induced human ASMC proliferation and migration through suppressing the activation of ERK1/2 and NF-κB signaling pathways.

Gene expression analysis in asthma using a targeted multiplex array

Background

Gene expression changes in the structural cells of the airways are thought to play a role in the development of asthma and airway hyperresponsiveness. This includes changes to smooth muscle contractile machinery and epithelial barrier integrity genes. We used a targeted gene expression arrays to identify changes in the expression and co-expression of genes important in asthma pathology.

Methods

RNA was isolated from the airways of donor lungs from 12 patients with asthma (8 fatal) and 12 non-asthmatics controls and analyzed using a multiplexed, hypothesis-directed platform to detect differences in gene expression. Genes were grouped according to their role in airway dysfunction: airway smooth muscle contraction, cytoskeleton structure and regulation, epithelial barrier function, innate and adaptive immunity, fibrosis and remodeling, and epigenetics.

Results

Differential gene expression and gene co-expression analyses were used to identify disease associated changes in the airways of asthmatics. There was significantly decreased abundance of integrin beta 6 and Ras-Related C3 Botulinum Toxin Substrate 1 (RAC1) in the airways of asthmatics, genes which are known to play an important role in barrier function. Significantly elevated levels of Collagen Type 1 Alpha 1 (COL1A1) and COL3A1 which have been shown to modulate cell proliferation and inflammation, were found in asthmatic airways. Additionally, we identified patterns of differentially co-expressed genes related to pathways involved in virus recognition and regulation of interferon production. 7 of 8 pairs of differentially co-expressed genes were found to contain CCCTC-binding factor (CTCF) motifs in their upstream promoters.

Conclusions

Changes in the abundance of genes involved in cell-cell and cell-matrix interactions could play an important role in regulating inflammation and remodeling in asthma. Additionally, our results suggest that alterations to the binding site of the transcriptional regulator CTCF could drive changes in gene expression in asthmatic airways. Several asthma susceptibility loci are known to contain CTCF motifs and so understanding the role of this transcription factor may expand our understanding of asthma pathophysiology and therapeutic options.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0545-9) contains supplementary material, which is available to authorized users.

Tenascin-C induces migration and invasion through JNK/c-Jun signalling in pancreatic cancer

Tenascin-C (TNC), a large extracellular matrix glycoprotein, has been reported to be associated with metastasis and poor prognosis in pancreatic cancer. However, the effects and mechanisms of TNC in pancreatic cancer metastasis largely remain unclear. We performed Transwell assays to investigate the effects of TNC on Capan-2, AsPC-1 and PANC-1 cells. In addition, western blot and RT-qPCR assays were used to examine potential TNC metastasis-associated targets, such as JNK/c-Jun, Paxillin/FAK, E-cadherin, N-cadherin, Vimentin, and MMP9/2. Lastly, we utilized a variety of methods, such as immunofluorescence, gelatin zymography and immunoprecipitation, to determine the molecular mechanisms of TNC in pancreatic cancer cell motility. The present study showed that TNC induced migration and invasion in pancreatic cancer cells and regulated a number of metastasis-associated proteins, including the EMT markers, MMP9 and Paxillin. Moreover, our data showed that TNC induced pancreatic cancer cells to generate an EMT phenotype and acquire motility potential through the activation of JNK/c-Jun signalling. In addition, TNC increased the DNA binding activity of c-Jun to the MMP9 promoter, an action likely resulting in increased MMP9 expression and activity. TNC/JNK also markedly induced the phosphorylation of Paxillin on serine 178, which is critical for the association between FAK and Paxillin and promoted the formation of focal adhesions. TNC/JNK initiates cell migration and invasion of pancreatic cancer cells through the promotion of EMT, the transactivation of MMP9 and the phosphorylation of Paxillin on serine 178. TNC may be a potential therapeutic target for treating pancreatic cancer metastasis.

Matrix Metalloproteinase-1 Activation Contributes to Airway Smooth Muscle Growth and Asthma Severity

RATIONALE

Matrix metalloproteinase-1 (MMP-1) and mast cells are present in the airways of people with asthma.

OBJECTIVES

To investigate whether MMP-1 could be activated by mast cells and increase asthma severity.

METHODS

Patients with stable asthma and healthy control subjects underwent spirometry, methacholine challenge, and bronchoscopy, and their airway smooth muscle cells were grown in culture. A second asthma group and control subjects had symptom scores, spirometry, and bronchoalveolar lavage before and after rhinovirus-induced asthma exacerbations. Extracellular matrix was prepared from decellularized airway smooth muscle cultures. MMP-1 protein and activity were assessed.

MEASUREMENTS AND MAIN RESULTS

Airway smooth muscle cells generated pro-MMP-1, which was proteolytically activated by mast cell tryptase. Airway smooth muscle treated with activated mast cell supernatants produced extracellular matrix, which enhanced subsequent airway smooth muscle growth by 1.5-fold (P < 0.05), which was dependent on MMP-1 activation. In asthma, airway pro-MMP-1 was 5.4-fold higher than control subjects (P = 0.002). Mast cell numbers were associated with airway smooth muscle proliferation and MMP-1 protein associated with bronchial hyperresponsiveness. During exacerbations, MMP-1 activity increased and was associated with fall in FEV₁ and worsening asthma symptoms.

CONCLUSIONS

MMP-1 is activated by mast cell tryptase resulting in a proproliferative extracellular matrix. In asthma, mast cells are associated with airway smooth muscle growth, MMP-1 levels are associated with bronchial hyperresponsiveness, and MMP-1 activation are associated with exacerbation severity. Our findings suggest that airway smooth muscle/mast cell interactions contribute to asthma severity by transiently increasing MMP activation, airway smooth muscle growth, and airway responsiveness.

Genetic variants associated with angiotensin-converting enzyme inhibitor-induced cough: a genome-wide association study in a Swedish population

Aim: We conducted a genome-wide association study on angiotensin-converting enzyme inhibitor-induced cough and used our dataset to replicate candidate genes identified in previous studies. Patients & methods: A total of 124 patients and 1345 treated controls were genotyped using Illumina arrays. The genome-wide significance level was set to p < 5 × 10-8. Results: We identified nearly genome-wide significant associations in CLASP1, PDE11A, KCNMB2, TGFA, SLC38A6 and MMP16. The strongest association was with rs62151109 in CLASP1 (odds ratio: 3.97; p = 9.44 × 10-8). All top hits except two were located in intronic or noncoding DNA regions. None of the candidate genes were significantly associated in our study. Conclusion: Angiotensin-converting enzyme inhibitor-induced cough is potentially associated with genes that are independent of bradykinin pathways.

Interstitial collagen turnover during airway remodeling in acute and chronic experimental asthma

Asthma airway remodeling is characterized by the thickening of the basement membrane (BM) due to an increase in extracellular matrix (ECM) deposition, which contributes to the irreversibility of airflow obstruction. Interstitial collagens are the primary ECM components to be increased during the fibrotic process. The aim of the present study was to examine the interstitial collagen turnover during the course of acute and chronic asthma, and 1 month after the last exposure to the allergen. Guinea pigs sensitized to ovalbumin (OVA) and exposed to 3 further OVA challenges (acute model) or 12 OVA challenges (chronic model) were used as asthma experimental models. A group of animals from either model was sacrificed 1 h or 1 month after the last OVA challenge. Collagen distribution, collagen content, interstitial collagenase activity and matrix metalloproteinase (MMP)-1, MMP-13 and tissue inhibitor of metalloproteinase (TIMP)-1 protein expression levels were measured in the lung tissue samples from both experimental models. The results revealed that collagen deposit in bronchiole BM, adventitial and airway smooth muscle layers was increased in both experimental models as well as lung tissue collagen concentration. These structural changes persisted 1 month after the last OVA challenge. In the acute model, a decrease in collagenase activity and in MMP-1 concentration was observed. Collagenase activity returned to basal levels, and an increase in MMP-1 and MMP-13 expression levels along with a decrease in TIMP-1 expression levels were observed in animals sacrificed 1 month after the last OVA challenge. In the chronic model, there were no changes in collagenase activity or in MMP-13 concentration, although MMP-1 expression levels increased. One month later, an increase in collagenase activity was observed, although MMP-1 and TIMP-1 levels were not altered. The results of the present study suggest that even when the allergen challenges were discontinued, and collagenase activity and MMP-1 expression increased, fibrosis remained, contributing to the irreversibility of bronchoconstriction.

Mechanisms of airway hyper-responsiveness in asthma: the past, present and yet to come

Airway hyper-responsiveness (AHR) has long been considered a cardinal feature of asthma. The development of the measurement of AHR 40 years ago initiated many important contributions to our understanding of asthma and other airway diseases. However, our understanding of AHR in asthma remains complicated by the multitude of potential underlying mechanisms which in reality are likely to have different contributions amongst individual patients. Therefore, the present review will discuss the current state of understanding of the major mechanisms proposed to contribute to AHR and highlight the way in which AHR testing is beginning to highlight distinct abnormalities associated with clinically relevant patient populations. In doing so we aim to provide a foundation by which future research can begin to ascribe certain mechanisms to specific patterns of bronchoconstriction and subsequently match phenotypes of bronchoconstriction with clinical phenotypes. We believe that this approach is not only within our grasp but will lead to improved mechanistic understanding of asthma phenotypes and we hoped to better inform the development of phenotype-targeted therapy.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.