Ciliary Beat Frequency Research Articles

Inflammation Increases the Opening State of Channels in the Epithelium, Releasing High Levels of ATP that Resulted in a Decrease on Mucociliary Transport Velocity in the Airways

ATP is one of the chemical signals locally released by the airway epithelium associated with an autocrine/paracrine mechanism to control basal ciliary beat frequency (CBF). A recent study has reported that ATP has a dual effect on CBF, since ATP (μM) increases CBF, but high levels of ATP (mM) significantly decreases CBF in cultures of mouse tracheal epithelial cell. This nucleotide can be released by different mechanisms that include hemichannels of connexins (Cx43) and pannexins (Panx1), and more recently the Calhm1 channel. In several cell types it has recently reported that in pathophysiological conditions, connexins and pannexins channels could modify their opening state. Furthermore, high levels of ATP have been measured in the bronchoalveolar fluid of asthmatic patients and ovoalbumin‐induced asthmatic mouse model (OVA). The asthmatic patients also have infiltration of inflammatory cells in the pulmonary epithelium, reduced CBF and mucociliary transport effectiveness. Mucociliary transport is the first defense mechanism in the airways, where particles are trapped in the mucus and removed by the ciliary beating to the pharynx. We proposed the following objective: Determine the relation between levels of ATP of an asthmatic OVA mouse model, the opening state of the channels that control the release of this nucleotide and the effectiveness of mucociliary transport in the airways. The protocols used in this study were approved, by the ethics committee of the university that follow international guidelines for animal care. We measured extracellular ([ATP]e) with a luminometric assay and evaluated the infiltration of inflammatory cells in the lung parenchyma by histochemistry (H&E). The ethidium bromide (5μM) capture was recorded with a camera mounted on an Olympus upright microscope. The microspheres (6μm) velocity on the surface of the trachea epithelium was registered with a videomicroscopy system and analyzed with the ImageJ program. We observed greater infiltration of inflammatory cells in the pulmonary parenchyma of the asthmatic mouse, compared with the control mouse. Also, we established that high levels of ATP were present in asthmatic mice trachea lavage compared to control animals. The microspheres velocity was diminished in OVA mouse model compare to control mice and addition of 1mM of ATP in control or asthmatic mice transiently stopped the microspheres movement. Furthermore, we observed a significant increase in the percentage of ethidium bromide capture by the epithelium of asthmatic mice compare to controls. These results demonstrated that in an inflammatory condition, channels involved in the ATP release increased their opening state in the airways epithelium. This effect could be associated to high levels of ATP measured in asthma, condition that resulted in a deleterious effect on mucociliary transport effectiveness.Support or Funding InformationCONICYT 21160416, LL.A. Millennium Institute on Immunology and Immunotherapy (P09/016‐F) MV.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Interleukin-13 Stimulation Reveals the Cellular and Functional Plasticity of the Airway Epithelium.

About 50% of patients with asthma exhibit chronic airway inflammation driven by the type 2 cytokines interleukin (IL)-4, IL-5, and IL-13. These patients with type 2-high asthma experience more allergic symptoms, greater airway hyperresponsiveness, and more severe mucus obstruction than patients with type 2-low asthma. Mouse models of asthma have shown that much of the airway dysfunction in these models can be generated by IL-13 stimulation of the airway epithelium alone. Both in vivo mouse model studies and in vitro studies of human mucociliary airway epithelial cultures have shown that IL-13 induces cellular remodeling of the airway epithelium through proliferation-independent transdifferentiation processes. In both humans and mice, IL-13 stimulation of the airway epithelium results in generation of hypersecretory mucin 5AC (MUC5AC)-expressing mucus cells. Whereas club cells have been shown to be the source of these mucin 5AC-positive mucus cells in mice, the origin of these mucus cells in humans is unclear. In humans, chronic IL-13 stimulation appears to result in loss of ciliated cells. Moreover, IL-13 stimulation can block ciliated cell differentiation from human basal airway epithelial cells. Coincident with IL-13 cellular remodeling are reported decreases in mucociliary transport and ciliary beat frequency. These IL-13-mediated changes in mucociliary function are accompanied by disorganization of cilia, a decrease in the ratio of mucin 5B (MUC5B) to mucin 5AC, and mucus gel tethering to the epithelial surface by mucin 5AC. These airway epithelial responses to IL-13 are mediated by multiple transcription factors, including signal transducer and activator of transcription-6 (STAT6), SAM pointed domain-containing Ets transcription factor (SPDEF), Forkhead box A2 (FOXA2), and Forkhead box J1 (FOXJ1). In addition, analysis of RNA-sequencing data derived from airway epithelial cells shows how IL-13 stimulation promotes broad changes in gene expression across the transcriptome. These results reveal the plastic nature of airway epithelial cells that enables the epithelium to undergo remodeling and functional shifts in response to IL-13 stimulation. With use of new technology, future studies should lead to greater understanding of how IL-13 and other stimuli of disease bring about airway epithelial remodeling, which may aid in the development of therapies that ameliorate airway dysfunction in asthma and other diseases.

Low Dose Carbon Black Nanoparticle Exposure Does Not Aggravate Allergic Airway Inflammation in Mice Irrespective of the Presence of Surface Polycyclic Aromatic Hydrocarbons.

Exposure to exogenous noxae, such as particulate matter, can trigger acute aggravations of allergic asthma—a chronic inflammatory airway disease. We tested whether Carbon Black nanoparticles (CBNP) with or without surface polycyclic aromatic hydrocarbons (PAH) aggravate an established allergic airway inflammation in mice. In an ovalbumin mouse model, Printex®90 (P90), P90 coated with benzo[a]pyrene (P90-BaP) or 9-nitroanthracene (P90-9NA), or acetylene soot exhibiting a mixture of surface PAH (AS-PAH) was administered twice (70 µL, 100 µg/mL) during an established allergic airway inflammation. We analyzed the immune cell numbers and chemokine/cytokine profiles in bronchoalveolar lavages, the mRNA expressions of markers for PAH metabolism (Cyp1a1, 1b1), oxidative stress (HO-1, Gr, Gpx-3), inflammation (KC, Mcp-1, IL-6, IL-13, IL-17a), mucin synthesis (Muc5ac, Muc5b), the histology of mucus-producing goblet cells, ciliary beat frequency (CBF), and the particle transport speed. CBNP had a comparable primary particle size, hydrodynamic diameter, and ζ-potential, but differed in the specific surface area (P90 > P90-BaP = P90-9NA = AS-PAH) and surface chemistry. None of the CBNP tested increased any parameter related to inflammation. The unmodified P90, however, decreased the tracheal CBF, decreased the Muc5b in intrapulmonary airways, but increased the tracheal Muc5ac. Our results demonstrated that irrespective of the surface PAH, a low dose of CBNP does not acutely aggravate an established allergic airway inflammation in mice.

The Role of Quinine-Responsive Taste Receptor Family 2 in Airway Immune Defense and Chronic Rhinosinusitis.

Bitter (T2R) and sweet (T1R) taste receptors in the airway are important in innate immune defense, and variations in taste receptor functionality in one T2R (T2R38) correlate with disease status and disease severity in chronic rhinosinusitis (CRS). Quinine is a bitter compound that is an agonist for several T2Rs also expressed on sinonasal cells, but not for T2R38. Because of this property, quinine may stimulate innate immune defense mechanisms in the airway, and functional differences in quinine perception may be reflective of disease status in CRS. Demographic and taste intensity data were collected prospectively from CRS patients and non-CRS control subjects. Sinonasal tissue from patients undergoing rhinologic surgery was also collected and grown at an air-liquid interface (ALI). Nitric oxide (NO) production and dynamic regulation of ciliary beat frequency in response to quinine stimulation were assessed in vitro. Quinine reliably increased ciliary beat frequency and NO production in ALI cultures in a manner consistent with T2R activation (p < 0.01). Quinine taste intensity rating was performed in 328 CRS patients and 287 control subjects demonstrating that CRS with nasal polyps (CRSwNP) patients rated quinine as significantly less intense than did control subjects. Quinine stimulates airway innate immune defenses by increasing ciliary beat frequency and stimulating NO production in a manner fitting with T2R activation. Patient variability in quinine sensitivity is observed in taste intensity ratings, and gustatory quinine "insensitivity" is associated with CRSwNP status. Thus, taste tests for quinine may be a biomarker for CRSwNP, and topical quinine has therapeutic potential as a stimulant of innate defenses.

Differential antiviral activities of respiratory syncytial virus (RSV) inhibitors in human airway epithelium

ObjectivesWe report the use of reconstituted 3D human airway epithelium cells (HuAECs) of bronchial origin in an air–liquid interface to study respiratory syncytial virus (RSV) infection and to assess the efficacy of RSV inhibitors in (pre-)clinical development.MethodsHuAECs were infected with RSV-A Long strain (0.01 CCID50/cell, where CCID50 represents 50% cell culture infectious dose in HEp2 cells) on the apical compartment of the culture. At the time of infection or at 1 or 3 days post-infection, selected inhibitors were added and refreshed daily on the basal compartment of the culture. Viral shedding was followed up by apical washes collected daily and quantifying viral RNA by RT-qPCR.ResultsRSV-A replicates efficiently in HuAECs and viral RNA is shed for weeks after infection. RSV infection reduces the ciliary beat frequency of the ciliated cells as of 4 days post-infection, with complete ciliary dyskinesia observed by day 10. Treatment with RSV fusion inhibitors resulted in an antiviral effect only when added at the time of infection. In contrast, the use of replication inhibitors (both nucleoside and non-nucleoside) elicited a marked antiviral effect even when the start of treatment was delayed until 1 day or even 3 days after infection. Levels of the inflammation marker RANTES (mRNA) increased ∼200-fold in infected, untreated cultures (at 3 weeks post-infection), but levels were comparable to those of uninfected cultures in the presence of PC786, an RSV replication inhibitor, suggesting that an efficient antiviral treatment might inhibit virus-induced inflammation in this model.ConclusionsOverall, HuAECs offer a robust and physiologically relevant model to study RSV replication and to assess the efficacy of antiviral compounds.

INVESTIGATION OF THE TRACHEAL MUCOCILIARY CLEARANCE IN SNAKES WITH AND WITHOUT BOID INCLUSION BODY DISEASE AND LUNG PATHOLOGY.

Pneumonia is a common complication of boid inclusion body disease (BIBD) in snakes. The tracheal mucociliary apparatus of eight boas ( Boa constrictor) and two pythons ( Python regius, Morelia viridis) was examined to assess whether absent or reduced mucociliary clearance could be a predisposing factor. Nine of the examined snakes were positive for BIBD by detection of inclusion bodies and three had lung pathologies other than the formation of inclusion bodies. A considerable individual variation of ciliary beat frequency (CBF, 3.0 ± 0.75 Hz to 7.8 ± 1.27 Hz), transport speed (23.1 ± 12.56 μm/sec to 189.2 ± 41.17 μm/sec), and transport direction (-12.5° ± 11.43° to 36.1° ± 7.53°) was found. CBFs of the BIBD-affected snakes with or without lung pathologies were markedly lower than ranges published for birds or mammals, but the net transport speeds and directions lay well within. The present investigation does therefore not reveal any signs of an inadequate mucociliary clearance in BIBD-affected snakes.

Does Heating up Saline for Nasal Irrigation Improve Mucociliary Function in Chronic Rhinosinusitis?

Background Mucociliary function is affected by temperature. Exposure to cold air may impair ciliary beat frequency. While saline nasal irrigation improves in ciliary beat activity, there is no evidence supporting the use of heated saline irrigation in treating patients with chronic rhinosinusitis. Objective To compare the effects of heated saline to room-temperature saline nasal irrigation on mucociliary clearance in chronic rhinosinusitis patients. Methods Adult patients with chronic rhinosinusitis were randomized into two groups receiving either heated saline or room-temperature saline nasal irrigation. Healthy subjects were included as control. Saccharin transit time was measured before and after nasal irrigation. Nasal patency was assessed by peak nasal inspiratory flow, anterior rhinomanometry, acoustic rhinometry, nasal obstruction score, and breathe-comfort score. Any adverse events were reported. Results Twenty-three patients with chronic rhinosinusitis and nine healthy subjects were enrolled. Saccharin transit time was decreased after nasal irrigation in both heated saline subgroup (baseline 12.3 ± 4.5 min vs. postirrigation 8.4 ± 4.9 min, p = 0.05) and room-temperature subgroup (baseline 12.8 ± 5.0 min vs. postirrigation 8.9 ± 4.2 min, p = 0.01). The saccharin transit time improvement was not different between heated saline (3.8 ± 6.2 min) and room-temperature saline (3.8 ± 4.0 min), p = 0.13. Postheated saline irrigation saccharin transit time of chronic rhinosinusitis patients (8.4 ± 4.9 min) was not different to healthy subjects (9.2 ± 3.7 min), p = 0.69. Nasal patency was not different between groups. There was no adverse event reported. Conclusion Nasal saline irrigation is beneficial to patients with chronic rhinosinusitis on mucociliary improvement. Warming saline is not necessary and adds no additional benefit to room-temperature saline irrigation.

Seihai-to (TJ-90)-Induced Activation of Airway Ciliary Beatings of Mice: Ca2+ Modulation of cAMP-Stimulated Ciliary Beatings via PDE1.

Sei-hai-to (TJ-90, Qing Fei Tang), a Chinese traditional medicine, increases ciliary beat frequency (CBF) and ciliary bend angle (CBA) mediated via cAMP (3′,5′-cyclic adenosine monophosphate) accumulation modulated by Ca2+-activated phosphodiesterase 1 (PDE1A). A high concentration of TJ-90 (≥40 μg/mL) induced two types of CBF increases, a transient increase (an initial increase, followed by a decrease) and a sustained increase without any decline, while it only sustained the CBA increase. Upon inhibiting increases in intracellular Ca2+ concentration ([Ca2+]i) by 10 μM BAPTA-AM (Ca2+-chelator, 1,2-Bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetrakis(acetoxymethyl ester) or Ca2+/calmodulin-dependent PDE1 by 8MmIBMX (a selective PDE1 inhibitor), TJ-90 (400 μg/mL) induced only the sustained CBF increase without any transient CBF increase. The two types of the CBF increase (the transient increase and the sustained increase) induced by TJ-90 (≥40 μg/mL) were mimicked by the stimulation with both procaterol (100 pM) and ionomycin (500 nM). Thus, TJ-90 stimulates small increases in the intracellular cAMP concentration ([cAMP]i) and [Ca2+]i in airway ciliary cells of mice. These small increases in [cAMP]i and [Ca2+]i cause inducing a transient CBF increase or a sustained CBF increase in an airway ciliary cells, depending on the dominant signal, Ca2+-signal, or cAMP-signal.

Clinical guidelines for diagnosis of primary ciliary dyskinesia

The diagnosis of primary ciliary dyskinesia is often confirmed with standard, albeit complex and expensive, tests. In many cases, however, the diagnosis remains difficult despite the array of sophisticated diagnostic tests. There is no “gold standard” reference test. Hence, a Task Force supported by the European Respiratory Society has developed this guideline to provide evidence-based recommendations on diagnostic testing, especially in light of new developments in such tests, and the need for robust diagnoses of patients who might enter randomised controlled trials of treatments. The guideline is based on pre-defined questions relevant for clinical care, a systematic review of the literature, and assessment of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. It focuses on clinical presentation, nasal nitric oxide, analysis of ciliary beat frequency and pattern by high-speed video-microscopy analysis, transmission electron microscopy, genotyping and immunofluorescence. It then used a modified Delphi survey to develop an algorithm for the use of diagnostic tests to definitively confirm and exclude the diagnosis of primary ciliary dyskinesia; and to provide advice when the diagnosis was not conclusive. Finally, this guideline proposes a set of quality criteria for future research on the validity of diagnostic methods for primary ciliary dyskinesia. This article has supplementary material available from erj.ersjournals.com Adopted from: Lucas J.S., Barbato A., Collins S.A., Goutaki M., Behan L., Caudri D., Dell Sh., Eber E., Escudier E., Hirst R.A., Hogg C., Jorissen M., Latzin Ph., Legendre M., Leigh M.W., Midulla F., Nielsen K.G., Omran H., Papon J.-F., Pohunek P., Redfern B., Rigau D., Rindlisbacher B., Santamaria F., Shoemark A., Snijders D., Tonia Th., Titieni A., Walker W.T., Werner C., Bush A., Kuehni C.E.. European Respiratory Society guidelines for the diagnosis of primary ciliary dyskinesia. Eur. Respir. J. 2017; 49 (1): 1601090. DOI: 10.1183/13993003.01090-2016.

A Systematic Review of the Association between Cigarette Smoke Exposure and Chronic Rhinosinusitis.

Objectives Cigarette smoking and passive smoke exposure have been associated with chronic rhinosinusitis (CRS). Our goal in this systematic review was to (1) determine if there was a strong correlative effect in large population studies between cigarette smoke exposure and the prevalence of CRS, (2) investigate pathogenic mechanisms of cigarette smoke in the upper airway, and (3) determine if a history of cigarette smoking affects the medical and surgical outcomes of CRS. Data Sources MEDLINE, Embase, Cochrane CENTRAL, Web of Science SCI and CPCI-S, and websites. Methods A comprehensive literature review and quantitative meta-analysis of studies based on the PRISMA protocol and examining the relationship between cigarette smoke exposure and CRS was performed. A search strategy was developed using various terms such as sinusitis, rhinitis, rhinosinusitis, and smoking. The articles were categorized by (1) epidemiology, (2) pathophysiology, and (3) outcomes. Data regarding study design, population/setting, methods, and bias were collected. Results The initial search generated 2621 titles/abstracts with 309 articles undergoing secondary review and 112 articles for final review. We determined that there is a strong correlation between active and passive cigarette smoke with the prevalence of CRS. Cigarette smoke challenge to sinonasal epithelia results in the release of inflammatory mediators and altered ciliary beat frequency. Pediatric patients exposed to secondhand smoke appear to have particularly poor outcomes. Conclusion There is clear evidence that cigarette smoke is related to CRS, but longitudinal and mechanistic studies are required to determine a causative effect. This information is critical for greater understanding of CRS health outcomes.

Ca2+ ]i modulation of cAMP-stimulated ciliary beat frequency via PDE1 in airway ciliary cells of mice.

What is the central question of this study? The ciliary beat frequency (CBF) of the airway is controlled by [Ca2+ ]i . However, the effects of a reduction in [Ca2+ ]i on CBF are still controversial (an increase, a decrease or no change). What is the main finding and its importance? This study demonstrated that [Ca2+ ]i directly regulates CBF (direct action) and also indirectly regulates CBF via cAMP accumulation controlled by Ca2+ -dependent PDE1 activity (indirect action). The final CBF is determined by the balance of direct and indirect actions. PDE1 plays crucial roles in the regulation of airway CBF. ABSTRACT: [Ca2+ ]i plays crucial roles in the regulation of ciliary beat frequency (CBF) and ciliary bend angle (CBA) of airway cilia. Moreover, Ca2+ -dependent PDE1A existing in the CBF-regulating metabolon of cilia modifies the CBF by regulating the cAMP accumulation. This study demonstrated that the CBF is regulated by a direct and an indirect action of [Ca2+ ]i ; the direct action changes CBF mediated via [Ca2+ ]i , and the indirect action changes CBF mediated via cAMP, the accumulation of which is controlled by PDE1 activity. Upon reducing [Ca2+ ]i to various levels, the direct action decreases CBF and the indirect action increases CBF. The final CBF is determined by the extent of cAMP accumulation, which is determined by the amount of inhibition of PDE1 activity, dependent on a reduction in [Ca2+ ]i ; a slight decrease induced by a nominally Ca2+ -free solution (no cAMP accumulation via PDE1) decreases CBF, and an extreme decrease induced by 50μm BAPTA-AM increases CBF via cAMP accumulation by inhibiting PDE1 in a similar manner to a PDE1 inhibitor (8MmIBMX). The increase in CBA in response to a reduction in [Ca2+ ]i is smaller than the increase in CBF, because no PDE1A exists in the CBA-regulating metabolon. On the contrary, an increase in [Ca2+ ]i induced by ionomycin, which decreases cAMP accumulation by PDE1A activation, caused a slower procaterol-stimulated increase in CBF than that decreased by a Ca2+ -free solution. A decrease in [Ca2+ ]i stimulates cAMP accumulation, whereas an increase in [Ca2+ ]i inhibits cAMP accumulation in airway ciliary cells. Thus, changes in [Ca2+ ]i modulate CBF and CBA via cAMP accumulation by controlling the activity of PDE1.

Motile cilia of human airway epithelia contain hedgehog signaling components that mediate noncanonical hedgehog signaling

Differentiated airway epithelia produce sonic hedgehog (SHH), which is found in the thin layer of liquid covering the airway surface. Although previous studies showed that vertebrate HH signaling requires primary cilia, as airway epithelia mature, the cells lose primary cilia and produce hundreds of motile cilia. Thus, whether airway epithelia have apical receptors for SHH has remained unknown. We discovered that motile cilia on airway epithelial cells have HH signaling proteins, including patched and smoothened. These cilia also have proteins affecting cAMP-dependent signaling, including Gαi and adenylyl cyclase 5/6. Apical SHH decreases intracellular levels of cAMP, which reduces ciliary beat frequency and pH in airway surface liquid. These results suggest that apical SHH may mediate noncanonical HH signaling through motile cilia to dampen respiratory defenses at the contact point between the environment and the lung, perhaps counterbalancing processes that stimulate airway defenses.

Sinus Microanatomy and Microbiota in a Rabbit Model of Rhinosinusitis.

Background: Rabbits are useful for preclinical studies of sinusitis because of similar physiologic features to humans. The objective of this study is to develop a rabbit model of sinusitis that permits assessment of microanatomy and sampling for evaluating shifts in the sinus microbiota during the development of sinusitis and to test how the mucociliary clearance (MCC) defect might lead to dysbiosis and chronic rhinosinusitis (CRS).Methods: Generation of CRS was accomplished with an insertion of a sterile sponge into the left middle meatus of New Zealand white rabbits (n = 9) for 2 weeks. After sponge removal, 4 rabbits were observed for another 10 weeks and evaluated for CRS using endoscopy, microCT, visualization of the functional micro-anatomy by micro-optical coherence tomography (μOCT), and histopathological analysis of the sinus mucosa. Samples were taken from the left middle meatus and submitted for microbiome analysis.Results: CT demonstrated opacification of all left sinuses at 2 weeks in all rabbits (n = 9), which persisted in animals followed for another 12 weeks (n = 4). Histology at week 2 showed mostly neutrophils. On week 14, significant infiltration of plasma cells and lymphocytes was noted with increased submucosal glands compared to controls (p = 0.02). Functional microanatomy at 2 weeks showed diminished periciliary layer (PCL) depth (p < 0.0001) and mucus transport (p = 0.0044) compared to controls despite a thick mucus layer. By 12 weeks, the thickened mucus layer was resolved but PCL depletion persisted in addition to decreased ciliary beat frequency (CBF; p < 0.0001). The mucin fermenting microbes (Lactobacillales, Bacteroidales) dominated on week 2 and there was a significant shift to potential pathogens (e.g., Pseudomonas, Burkholderia) by week 14 compared to both controls and the acute phase (p < 0.05).Conclusion: We anticipate this reproducible model will provide a means for identifying underlying mechanisms of airway-surface liquid (ASL) depletion and fundamental changes in sinus microbial communities that contribute to the development of CRS. The rabbit model of sinusitis exhibited diminished PCL depth with delayed mucus transport and significant alterations and shift in the sinus microbiome during the development of chronic inflammation.

Nitric oxide activation by progesterone suppresses ATP-induced ciliary activity in oviductal ciliated cells.

Ciliary beat frequency (CBF) regulates the oviductal transport of oocytes and embryos, which are important components of the reproductive process. Local release of ATP transiently increases CBF by increasing [Ca2+]i. Ovarian hormones also regulate ciliary activity and oviductal transport. Progesterone (P4) induces nitric oxide (NO) production and high P4 concentrations induce ciliary dysfunction. However, the mechanism by which P4 affects CBF has not been elucidated. To evaluate the role of P4 in NO production and its effect on ATP-induced increases in CBF, we measured CBF, NO concentrations and [Ca2+]i in cultures of oviductal ciliated cells treated with P4 or NO signalling-related molecules. ATP induced a [Ca2+]i peak, followed by an increase in NO concentrations that were temporally correlated with the decreased phase of the transiently increased CBF. Furthermore, P4 increased the expression of nitric oxide synthases (iNOS and nNOS) and reduced the ATP-induced increase in CBF via a mechanism that involves the NO signalling pathway. These results have improved our knowledge about intracellular messengers controlling CBF and showed that NO attenuates oviduct cell functions. Furthermore, we showed that P4 regulates neurotransmitter (ATP) actions on CBF via the NO pathway, which could explain pathologies where oviductal transport is altered and fertility decreased.

ЦИЛИАРНАЯ АКТИВНОСТЬ МЕРЦАТЕЛЬНОГО ЭПИТЕЛИЯ БРОНХОВ ПРИ ХОЛОДОВОМ ВОЗДЕЙСТВИИ В ЭКСПЕРИМЕНТЕ IN VITRO

To date, the role of dysfunction of the bronchial ciliated epithelium (BCE) in the formation of mucociliary disorders during cold exposure has not been fully established. The aim of the study was to investigate the nature and severity of changes in the ciliary motility of the BCE under the influence of a cold stimulus in vitro. Ten volunteers with asthma underwent a bronchoscopy with biopsy of the lobar bronchus mucosa. The biopsy specimens were placed in a Hank’s balanced salt solution (HBSS) on a slide, located on the thermal stage, used to simulate the effect of various temperature on the BCE. Ciliary beat frequency (CBF, Hz) was recorded using a microscope, high-sensitivity digital camera and computer with specially developed software. The initial recording of CBF was performed at 24ºC, after which the temperature of HBSS was gradually increased to physiological level and repeated recording was made at the control points (28ºC and 36ºC). Then, the temperature of the solution was lowered and CBF was registered again at 28ºC, 21ºC and 17ºC. The initial CBF of the BCE varied from 6.74 to 3.77 Hz with average of 5.25±1.48 Hz (M±m). There was a statistically significant increase in CBF when the solution was heated: at 28ºC it was 6.33±1.36 Hz (p=0.004) and remained at this level up to 36ºC – 7.14±1.33 Hz (p=0.002). A gradual decrease in the solution temperature produced a reduction in CBF in comparison with the physiological conditions: 28ºC – 6.12±1.31 Hz (p=0.121), 21ºC – 5.27±1.32 Hz (p=0.001) and 17ºC – 3.95±1.18 Hz (p=0.0001). By the end of the experiment, CBF of the BCE decreased almost 2-fold in comparison with the physiological conditions. A mathematical model that characterizes the behavior of BCE cilia under cold stress was developed. Thus, the results of the study demonstrate a marked decrease in the motor activity of the BCE cilia under cold stress, which underlines a significant contribution of the functional disturbance of BCE to the pathophysiological mechanisms of hypersecretory disorders induced by inhalation of cold air.

Characterization of pediatric cystic fibrosis airway epithelial cell cultures at the air-liquid interface obtained by non-invasive nasal cytology brush sampling

BackgroundIn vitro systems of primary cystic fibrosis (CF) airway epithelial cells are an important tool to study molecular and functional features of the native respiratory epithelium. However, undifferentiated CF airway cell cultures grown under submerged conditions do not appropriately represent the physiological situation. A more advanced CF cell culture system based on airway epithelial cells grown at the air-liquid interface (ALI) recapitulates most of the in vivo-like properties but requires the use of invasive sampling methods. In this study, we describe a detailed characterization of fully differentiated primary CF airway epithelial cells obtained by non-invasive nasal brushing of pediatric patients.MethodsDifferentiated cell cultures were evaluated with immunolabelling of markers for ciliated, mucus-secreting and basal cells, and tight junction and CFTR proteins. Epithelial morphology and ultrastructure was examined by histology and transmission electron microscopy. Ciliary beat frequency was investigated by a video-microscopy approach and trans-epithelial electrical resistance was assessed with an epithelial Volt-Ohm meter system. Finally, epithelial permeability was analysed by using a cell layer integrity test and baseline cytokine levels where measured by an enzyme-linked immunosorbent assay.ResultsPediatric CF nasal cultures grown at the ALI showed a differentiation into a pseudostratified epithelium with a mucociliary phenotype. Also, immunofluorescence analysis revealed the presence of ciliated, mucus-secreting and basal cells and tight junctions. CFTR protein expression was observed in CF (F508del/F508del) and healthy cultures and baseline interleukin (IL)-8 and IL-6 release were similar in control and CF ALI cultures. The ciliary beat frequency was 9.67 Hz and the differentiated pediatric CF epithelium was found to be functionally tight.ConclusionIn summary, primary pediatric CF nasal epithelial cell cultures grown at the ALI showed full differentiation into ciliated, mucus-producing and basal cells, which adequately reflect the in vivo properties of the human respiratory epithelium.

A 3D Human Airway Model Enables Prediction of Respiratory Toxicity of Inhaled Drugs In Vitro.

Respiratory tract toxicity represents a significant cause of attrition of inhaled drug candidates targeting respiratory diseases. One of the key issues to allow early detection of respiratory toxicities is the lack of reliable and predictive in vitro systems. Here, the relevance and value of a physiologically relevant 3D human airway in vitro model (MucilAir) were explored by repeated administration of a set of compounds with (n = 8) or without (n = 7) respiratory toxicity following inhalation in vivo. Predictability for respiratory toxicity was evaluated by readout of cytotoxicity, barrier integrity, viability, morphology, ciliary beating frequency, mucociliary clearance and cytokine release. Interestingly, the data show that in vivo toxicity can be predicted in vitro by studying cell barrier integrity by transepithelial electrical resistance (TEER), and cell viability determined by the Resazurin method. Both read-outs had 88% sensitivity and 100% specificity, respectively, while the former was more accurate with receiver operating characteristic (ROC) AUC of 0.98 (p = .0018) compared with ROC AUC of 0.90 (p = .0092). The loss of cell barrier integrity could mainly, but not fully, be attributed to a loss of cell coverage in 6 out of 7 compounds with reduced TEER. Notably, these effects occurred only at 400 µM, at concentration levels significantly above primary target cell potency, suggesting that greater attention to high local lung concentrations should be taken into account in safety assessment of inhaled drugs. Thus, prediction of respiratory toxicity in 3D human airway in vitro models may result in improved animal welfare and reduced attrition in inhaled drug discovery projects.

Effects of organic and inorganic compounds of diesel exhaust particles on the mucociliary epithelium: An experimental study on the frog palate preparation

The toxic actions of acute exposition to different diesel exhaust particles (DEPA) fractions on the mucociliary epithelium are not yet fully understood due to different concentrations of organic and inorganic elements. These chemicals elements produce damage to the respiratory epithelium and exacerbate pre-existent diseases. In our study we showed these differences in two experimental studies. Study I (dose-response curve - DRCS): Forty frog-palates were exposed to the following dilutions: frog ringer, intact DEPA diluted in frog-ringer at 3mg/L, 6mg/L and 12mg/L. Study II (DEPF) (DEPA fractions diluted at 12mg/L): Fifty palates - Frog ringer, intact DEPA, DEPA treated with hexane, nitric acid and methanol. Variables analyzed: relative time of mucociliary transport (MCT), ciliary beating frequency (CBF) and morphometric analysis for mucin profile (neutral/acid) and vacuolization. The Results of DRCS: Group DEPA-12mg/L presented a significant increase in the MCT (p<0.05), proportional volume of acid mucus (p<0.05) and decreased proportional volume of neutral mucus and vacuoles (p<0.05). In relation of DEPF: A significant increase in the MCT associated to a decrease in the proportional volume of neutral mucus was founded in nitric acid group. In addition, a significant increase in the proportional volume of acid mucus was found in methanol group. We concluded that: 1) Increasing concentrations of intact DEPA can progressively increase MCT and promote an acidification of intra-epithelial mucins associated to a depletion of neutral mucus. 2) Intact DEPA seem to act as secretagogue substance, promoting mucus extrusion and consequently reducing epithelial thickness. 3) Organic fraction of low polarity seems to play a pivotal role on the acute toxicity to the mucociliary epithelium, by promoting a significant increase in the MCT associated to changes in the chemical profile of the intracellular mucins.

PLACE OF MUKOACTIVE THERAPY OF RINOSINUSITIS IN INTERNATIONAL AND RUSSIAN GUIDELINES

Excessive accumulation of mucous secretions in the nasal cavity and paranasal sinuses is key drivers in the pathogenesis of rhinosinusitis. Mucoactive drugs are actively used to combat this phenomenon. Mucoactive drugs promote mucosal secretion clearance due to increase of ciliary beat frequency in ciliated epithelium and decrease in the viscosity of secretion by means of hydrolysis of disulfide bonds and increased mucus moisture. The lack of clinical trials that meet the requirements of evidencebased medicine did not allow to include this class of drugs in the official guidelines for a long time. However, thanks to the latest results, phytopreparations including a mucoactive plant preparation Myrtol standardized have been introduced into the European position paper on rhinosinusitis and nasal polyps (EPOS 2012). A large randomized double-blind multicenter study involving more than 300 patients with acute rhinosinusitis showed that administration of Mirtol standardized facilitates acceleration of the regression of the disease symptoms, reduces the need for antibiotic therapy and reduces the period of disability as compared to taking placebo. The results of this and other clinical studies allowed Myrtol to take a rightful place in the international and domestic guidelines.

Silica nanoparticles inhibit the cation channel TRPV4 in airway epithelial cells

BackgroundSilica nanoparticles (SiNPs) have numerous beneficial properties and are extensively used in cosmetics and food industries as anti-caking, densifying and hydrophobic agents. However, the increasing exposure levels experienced by the general population and the ability of SiNPs to penetrate cells and tissues have raised concerns about possible toxic effects of this material. Although SiNPs are known to affect the function of the airway epithelium, the molecular targets of these particles remain largely unknown. Given that SiNPs interact with the plasma membrane of epithelial cells we hypothesized that they may affect the function of Transient Receptor Potential Vanilloid 4 (TRPV4), a cation-permeable channel that regulates epithelial barrier function. The main aims of this study were to evaluate the effects of SiNPs on the activation of TRPV4 and to determine whether these alter the positive modulatory action of this channel on the ciliary beat frequency in airway epithelial cells.ResultsUsing fluorometric measurements of intracellular Ca2+ concentration ([Ca2+]i) we found that SiNPs inhibit activation of TRPV4 by the synthetic agonist GSK1016790A in cultured human airway epithelial cells 16HBE and in primary cultured mouse tracheobronchial epithelial cells. Inhibition of TRPV4 by SiNPs was confirmed in intracellular Ca2+ imaging and whole-cell patch-clamp experiments performed in HEK293T cells over-expressing this channel. In addition to these effects, SiNPs were found to induce a significant increase in basal [Ca2+]i, but in a TRPV4-independent manner. SiNPs enhanced the activation of the capsaicin receptor TRPV1, demonstrating that these particles have a specific inhibitory action on TRPV4 activation. Finally, we found that SiNPs abrogate the increase in ciliary beat frequency induced by TRPV4 activation in mouse airway epithelial cells.ConclusionsOur results show that SiNPs inhibit TRPV4 activation, and that this effect may impair the positive modulatory action of the stimulation of this channel on the ciliary function in airway epithelial cells. These findings unveil the cation channel TRPV4 as a primary molecular target of SiNPs.