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Developmental Biology Jul 2019Mucus secretion and mucociliary clearance are crucial processes required to maintain pulmonary homeostasis. In the trachea and nasal passages, mucus is secreted by...
Mucus secretion and mucociliary clearance are crucial processes required to maintain pulmonary homeostasis. In the trachea and nasal passages, mucus is secreted by submucosal glands (SMGs) that line the airway, with an additional contribution from goblet cells of the surface airway epithelium. The SMG mucus is rich in mucins and antimicrobial enzymes. Defective tracheal SMGs contribute to hyper-secretory respiratory diseases, such as cystic fibrosis, asthma, and chronic obstructive pulmonary disease, however little is known about the signals that regulate their morphogenesis and patterning. Here, we show that Fgf10 is essential for the normal development of murine tracheal SMGs, with gland development arresting at the early bud stage in the absence of FGF10 signalling. As Fgf10 knockout mice are lethal at birth, inducible knockdown of Fgf10 at late embryonic stages was used to follow postnatal gland formation, confirming the essential role of FGF10 in SMG development. In heterozygous Fgf10 mice the tracheal glands formed but with altered morphology and restricted distribution. The reduction in SMG branching in Fgf10 heterozygous mice was not rescued with time and resulted in a reduction in overall tracheal mucus secretion. Fgf10 is therefore a key signal in SMG development, influencing both the number of glands and extent of branching morphogenesis, and is likely, therefore, to play a role in aspects of SMG-dependent respiratory health.
Topics: Animals; Crosses, Genetic; Exocrine Glands; Female; Fibroblast Growth Factor 10; Male; Mice; Morphogenesis; Mucus; Respiratory Mucosa; Trachea
PubMed: 30965042
DOI: 10.1016/j.ydbio.2019.03.017 -
Scientific Reports Aug 2019Replacement of large tracheal defects remains an unmet clinical need. While recellularization of acellular tracheal grafts appeared to be a viable pathway, evidence from...
Replacement of large tracheal defects remains an unmet clinical need. While recellularization of acellular tracheal grafts appeared to be a viable pathway, evidence from the clinic suggests otherwise. In hindsight, complete removal of chondrocytes and repopulation of the tracheal chondroid matrix to achieve functional tracheal cartilage may have been unrealistic. In contrast, the concept of a hybrid graft whereby the epithelium is removed and the immune-privileged cartilage is preserved is a radically different path with initial reports indicating potential clinical success. Here, we present a novel approach using a double-chamber bioreactor to de-epithelialize tracheal grafts and subsequently repopulate the grafts with exogenous cells. A 3 h treatment with sodium dodecyl sulfate perfused through the inner chamber efficiently removes the majority of the tracheal epithelium while the outer chamber, perfused with growth media, keeps most (68.6 ± 7.3%) of the chondrocyte population viable. De-epithelialized grafts support human bronchial epithelial cell (BEAS-2B) attachment, viability and growth over 7 days. While not without limitations, our approach suggests value in the ultimate use of a chimeric allograft with intact donor cartilage re-epithelialized with recipient-derived epithelium. By adopting a brief and partial decellularization approach, specifically removing the epithelium, we avoid the need for cartilage regeneration.
Topics: Allografts; Animals; Cell Survival; Chondrocytes; Extracellular Matrix; Fluorescent Antibody Technique; Mechanical Phenomena; Re-Epithelialization; Regenerative Medicine; Respiratory Mucosa; Swine; Tissue Engineering; Trachea; Transplantation, Homologous
PubMed: 31427611
DOI: 10.1038/s41598-019-48450-4 -
FEBS Letters May 2006Toll-like receptors (TLR) detect pathogen-associated molecular patterns (PAMP) and play a crucial role in triggering immunity. Due to their large surfaces in direct... (Review)
Review
Toll-like receptors (TLR) detect pathogen-associated molecular patterns (PAMP) and play a crucial role in triggering immunity. Due to their large surfaces in direct contact with the environment, mucosal tissues are the major sites of PAMP-TLR signalling. How innate and adaptive immunity are triggered through flagellin-TLR5 interaction is the main focus of the review. In view of recent reports on genetic polymorphism, we will summarize the impact of TLR5 on the susceptibility to mucosal infections and on various immuno-pathologies. Finally, the contribution of TLRs in the induction and maintenance of mucosal homeostasis and commensal discrimination is discussed.
Topics: Bacterial Physiological Phenomena; Flagellin; Intestinal Mucosa; Mucous Membrane; Toll-Like Receptor 5; Trachea
PubMed: 16650409
DOI: 10.1016/j.febslet.2006.04.036 -
Journal of Physiology and Pharmacology... Feb 2019Dexamethasone inhibits mucin secretion considering the primary option for treating acute asthma exacerbation. However, the mechanism underlying dexamethasone-induced...
Dexamethasone inhibits mucin secretion considering the primary option for treating acute asthma exacerbation. However, the mechanism underlying dexamethasone-induced decreased in mucosecretion is unclear. Recent studies have reported that dexamethasone exerts an inhibitory effect on mucosecretion in the lung by modulating the expression of calcium processing genes. However, the expression of the calcium processing genes in the trachea is not examined yet. Thus, the present study is the first to report the localization of calcium processing proteins such as transient receptor potential vanilloid-4 (Trpv4), transient receptor potential vanilloid-6 (Trpv6), calbindin-D (CaBP-9k) and plasma membrane Ca-ATPase 1 (Pmca1) in the mouse trachea and their glucocorticoid-induced response. In this study, mice were subcutaneously injected with dexamethasone for 5 days, and their tracheal samples were collected by dividing the trachea into the cervical, and thoracic sections based on its anatomical structure. The localization of TRPV4, TRPV6, CaBP-9k, and PMCA1 proteins was detected in the tracheal epithelium, submucosal glands, cartilages and muscles. Dexamethasone treatment downregulated the mRNA expression of the four calcium processing genes and mucin producing genes. The dexamethasone-induced decrease in the secretion of mucosubstances in the trachea was determined by performing Alcian blue-periodic acid-Schiff staining. Thus, the findings of the present study suggest that glucocorticoids simultaneously can regulate the expression of calcium processing genes and tracheal mucosecretion.
Topics: Animals; Calcium Channels; Dexamethasone; Female; Glucocorticoids; Male; Mice, Inbred C57BL; Plasma Membrane Calcium-Transporting ATPases; Respiratory Mucosa; S100 Calcium Binding Protein G; TRPV Cation Channels; Trachea
PubMed: 31172971
DOI: 10.26402/jpp.2019.1.12 -
Physiological Research Mar 2020The sinonasal mucosa has an essential role in defense mechanisms of the upper respiratory tract. The innate immune system presents the primary defense against noxious... (Review)
Review
The sinonasal mucosa has an essential role in defense mechanisms of the upper respiratory tract. The innate immune system presents the primary defense against noxious microorganisms followed by induction of the adaptive immune mechanisms as a consequence of the presence of pathogens. This well-known activation of adaptive immune system in response to presence of the antigen on mucosal surfaces is now broadly applicated in vaccinology research. Prevention of infectious diseases belongs to substantial challenges in maintaining the population health. Non-invasive, easily applicable mucosal vaccination purposes various research opportunities that could be usable in daily practice. However, the existence of multiple limitations such as rapid clearance of vaccine from nasal mucosa by means of mucociliary transport represents a great challenge in development of safe and efficient vaccines. Here we give an updated view on nasal functions with focus on nasal mucosal immunity and its potential application in vaccination in nearly future.
Topics: Administration, Intranasal; Animals; Humans; Immunity, Mucosal; Laryngeal Mucosa; Nasal Mucosa; Respiratory Mucosa; Trachea; Vaccines
PubMed: 32228012
DOI: 10.33549/physiolres.934404 -
The Journal of Biological Chemistry Jan 2016Many cells, including murine airway epithelial cells, respond to a variety of inflammatory stimuli by synthesizing leukocyte-adhesive hyaluronan (HA) cables that remain...
Many cells, including murine airway epithelial cells, respond to a variety of inflammatory stimuli by synthesizing leukocyte-adhesive hyaluronan (HA) cables that remain attached to their cell surfaces. This study shows that air-liquid interface cultures of murine airway epithelial cells (AECs) also actively synthesize and release a majority of their HA onto their ciliated apical surfaces to form a heavy chain hyaluronan (HC-HA) matrix in the absence of inflammatory stimuli. These matrices do not resemble the rope-like HA cables but occur in distinct sheets or rafts that can capture and embed leukocytes from cell suspensions. The HC-HA modification involves the transfer of heavy chains from the inter-α-inhibitor (IαI) proteoglycan, which has two heavy chains (HC1 and HC2) on its chondroitin sulfate chain. The transesterification transfer of HCs from chondroitin sulfate to HA is mediated by tumor necrosis factor-induced gene 6 (TSG-6), which is up-regulated in inflammatory reactions. Because the AEC cultures do not have TSG-6 nor serum, the source of IαI, assays for HCs and TSG-6 were done. The results show that AECs synthesize TSG-6 and their own heavy chain donor (pre-IαI) with a single heavy chain 3 (HC3), which are also constitutively expressed by human renal proximal tubular epithelial cells. These leukocyte adhesive HC3-HA structures were also found in the bronchoalveolar lavage of naïve mice and were observed on their apical ciliated surfaces. Thus, these leukocyte-adhesive HA rafts are now identified as HC3-HA complexes that could be part of a host defense mechanism filling some important gaps in our current understanding of murine airway epithelial biology and secretions.
Topics: Alpha-Globulins; Animals; Bronchoalveolar Lavage Fluid; Cell Adhesion; Cell Adhesion Molecules; Cell Line; Cell Polarity; Cells, Cultured; Female; Humans; Hyaluronic Acid; Immunity, Mucosal; Male; Membrane Microdomains; Mice, Inbred BALB C; Mice, Knockout; Molecular Weight; Monocytes; Proteoglycans; Respiratory Mucosa; Trachea
PubMed: 26601955
DOI: 10.1074/jbc.M115.704288 -
The Journal of Thoracic and... Jul 2004
Topics: Animals; Humans; Mouth Mucosa; Prosthesis Design; Prosthesis Implantation; Tissue Engineering; Trachea
PubMed: 15224015
DOI: 10.1016/j.jtcvs.2003.11.069 -
Tissue Engineering and Regenerative... Aug 2020Respiratory mucosa defects result in airway obstruction and infection, requiring subsequent functional recovery of the respiratory epithelium. Because site-specific...
BACKGROUND
Respiratory mucosa defects result in airway obstruction and infection, requiring subsequent functional recovery of the respiratory epithelium. Because site-specific extracellular matrix (ECM) facilitates restoration of organ function by promoting cellular migration and engraftment, previous studies considered decellularized trachea an ideal ECM; however, incomplete cell removal from cartilage and mucosal-architecture destruction are frequently reported. Here, we developed a decellularization protocol and applied it to the respiratory mucosa of separated porcine tracheas.
METHODS
The trachea was divided into groups according to decellularization protocol: native mucosa, freezing-thawing (FT), FT followed by the use of Perasafe-based chemical agents before mucosal separation (wFTP), after mucosal separation (mFTP), and followed by DNase decellularization (mFTD). Decellularization efficacy was evaluated by DNA quantification and hematoxylin and eosin staining, and ECM content of the scaffold was evaluated by histologic analysis and glycosaminoglycan and collagen assays. Biocompatibility was assessed by cell-viability assay and in vivo transplantation.
RESULTS
The mFTP mucosa showed low antigenicity and maintained the ECM to form a proper microstructure. Additionally, tonsil-derived stem cells remained viable when cultured with or seeded onto mFTP mucosa, and the in vivo host response showed a constructive pattern following implantation of the mFTP scaffolds.
CONCLUSION
These results demonstrated that xenogenic acellular respiratory mucosa matrix displayed suitable biocompatibility as a scaffold material for respiratory mucosa engineering.
Topics: Animals; Extracellular Matrix; Respiratory Mucosa; Swine; Tissue Engineering; Tissue Scaffolds; Trachea
PubMed: 32390116
DOI: 10.1007/s13770-020-00260-w -
British Journal of Pharmacology Apr 2012Removal of disease-driving inflammatory leucocytes is central to resolution of inflammation. The current pharmacological dogma teaches leucocyte elimination through... (Review)
Review
Removal of disease-driving inflammatory leucocytes is central to resolution of inflammation. The current pharmacological dogma teaches leucocyte elimination through apoptosis followed by phagocytosis. However, actual resolving roles of apoptotic-phagocytic processes have been difficult to demonstrate in the major diseases that are characterized by mucosal tissue inflammation. Many current in vivo observations rather demonstrate that leucocyte elimination occurs by transepithelial locomotion. Findings in diseased gut and bladder mucosae support this notion. Respiratory disease data are particularly compelling. Eosinophils and neutrophils abound in sputum and tracheal aspirates during treatment-induced recovery from severe asthma. Prolonged sputum neutrophilia, along with clinical improvement, follows upon smoking cessation in COPD. Eosinophils, neutrophils, lymphocytes, mast cells and dendritic cells also move in large numbers into the bronchial lumen at spontaneous inflammation resolution following allergen challenge in allergic rhinitis and asthma. A corresponding reduction of infiltrated cells in the bronchial mucosal tissue demonstrates efficiency of the transepithelial elimination pathway. Underscoring its operational role, drugs impeding transepithelial elimination of leucocytes aggravate mucosal/parenchymal inflammation. Hence, relying on lumen cell data alone can lead to paradoxical conclusions regarding anti-inflammatory drug efficacy. Conversely, drugs promoting non-injurious transepithelial elimination of leucocytes could resolve mucosal inflammatory diseases.
Topics: Animals; Apoptosis; Cell Movement; Drug Discovery; Humans; Inflammation; Leukocytes; Models, Biological; Mucous Membrane
PubMed: 22053825
DOI: 10.1111/j.1476-5381.2011.01772.x -
Infection and Immunity Oct 2017, the primary etiologic agent of chronic respiratory disease (CRD) in poultry, leads to prolonged recruitment and activation of inflammatory cells in the respiratory...
, the primary etiologic agent of chronic respiratory disease (CRD) in poultry, leads to prolonged recruitment and activation of inflammatory cells in the respiratory mucosa. This is consistent with the current model of immune dysregulation that ostensibly allows the organism to evade clearance mechanisms and establish chronic infection. To date, studies using quantitative reverse transcription-PCR (qRT-PCR) and microarrays have shown a significant transient upregulation of cytokines and chemokines from tracheal epithelial cells (TECs) and tracheal tissue in response to virulent strain R that contributes to the infiltration of inflammatory cells into the tracheal mucosa. To expand upon these experiments, RNA was isolated from tracheas of 20 chickens infected with R and 20 mock-infected animals at days 1, 3, 5, and 7 postinoculation, and samples were analyzed for differential gene expression using Illumina RNA sequencing. A rapid host response was observed 24 h postinfection, with over 2,500 significantly differentially expressed genes on day 3, the peak of infection. Many of these genes have immune-related functions involved in signaling pathways, including Toll-like receptor (TLR), mitogen-activated protein kinase, Jak-STAT, and the nucleotide oligomerization domain-like receptor pathways. Of interest was the increased expression of numerous cell surface receptors, including TLR4 and TLR15, which may contribute to the production of cytokines. Metabolic pathways were also activated on days 1 and 3 postinfection, ostensibly due to epithelial cell distress that occurs upon infection. Early perturbations in tissue-wide gene expression, as observed here, may underpin a profound immune dysregulation, setting the stage for disease manifestations characteristic of infection.
Topics: Animals; Chemokines; Chickens; Cytokines; Gene Expression Profiling; Metabolic Networks and Pathways; Mycoplasma Infections; Mycoplasma gallisepticum; Poultry Diseases; Real-Time Polymerase Chain Reaction; Respiratory Mucosa; Sequence Analysis, RNA; Signal Transduction; Toll-Like Receptor 4; Toll-Like Receptors; Trachea
PubMed: 28739827
DOI: 10.1128/IAI.00343-17