Bronchial Remodeling Research Articles

Severe Reduction in Number and Function of Peripheral T Cells Does Not Afford Protection toward Emphysema and Bronchial Remodeling Induced in Mice by Cigarette Smoke

The protein Lck (p56(Lck)) is a Src family tyrosine kinase expressed at all stages of thymocyte development and is required for maturation of T cells. The targeted disruption of Lck gene in mice results in severe block in thymocyte maturation with substantial reduction in the development of CD4(+)CD8(+) thymocytes, severe reduction of peripheral T cells, and disruption of T-cell receptor signaling with defective function of T-cell responses. To investigate the role of T lymphocyte in the development of cigarette smoke-induced pulmonary changes, Lck(-/-) mice and corresponding congenic wild-type mice were chronically exposed to cigarette smoke, and their lungs were analyzed by biochemical, immunologic, and morphometric methods. Smoking mice from both genotypes showed disseminated foci of emphysema and large areas of goblet cell metaplasia in bronchial and bronchiolar epithelium. Morphometric evaluation of lung changes and lung elastin determination confirmed that mice from both genotypes showed the same degree of emphysematous lesions. Thus, cigarette smoke exposure in the presence of severe reduction in number and function of peripheral T cells does not influence the development of pulmonary changes induced by cigarette smoke. The data obtained suggest that innate immunity is a leading actor in the early development of pulmonary changes in smoking mice and that the adaptive immune response may play a role at later stages.

Protection from Cigarette Smoke-Induced Lung Dysfunction and Damage by H2 Relaxin (Serelaxin).

Cigarette smoke (CS) is the major etiologic factor of chronic obstructive pulmonary disease (COPD), which is characterized by airway remodeling, lung inflammation and fibrosis, emphysema, and respiratory failure. The current therapies can improve COPD management but cannot arrest its progression and reduce mortality. Hence, there is a major interest in identifying molecules susceptible of development into new drugs to prevent or reduce CS-induced lung injury. Serelaxin (RLX), or recombinant human relaxin-2, is a promising candidate because of its anti-inflammatory and antifibrotic properties highlighted in lung disease models. Here, we used a guinea pig model of CS-induced lung inflammation, and remodeling reproducing some of the hallmarks of COPD. Animals exposed chronically to CS (8 weeks) were treated with vehicle or RLX, delivered by osmotic pumps (1 or 10 μg/day) or aerosol (10 μg/ml/day) during CS treatment. Controls were nonsmoking animals. RLX maintained airway compliance to a control-like pattern, likely because of its capability to counteract lung inflammation and bronchial remodeling. In fact, treatment of CS-exposed animals with RLX reduced the inflammatory recruitment of leukocytes, accompanied by a significant reduction of the release of proinflammatory cytokines (tumor necrosis factor α and interleukin-1β). Moreover, RLX was able to counteract the adverse bronchial remodeling and emphysema induced by CS exposure by reducing goblet cell hyperplasia, smooth muscle thickening, and fibrosis. Of note, RLX delivered by aerosol has shown a comparable efficacy to systemic administration in reducing CS-induced lung dysfunction and damage. In conclusion, RLX emerges as a new molecule to counteract CS-induced inflammatory lung diseases.

Bronchial asthma and chronic kidney disease: possible pathogenetic role of inflammatory cytokines

The aim is analysis of possible influence of pro- and antiinflammatory cytokine having key pathogenetic value on the glomerular filtration rate in bronchial asthma (BA). Material and methods. We examined 51 patients with BA. Glomerular filtration rate (eGFR) by CKD-EPI was estimated. The content of IL-4, IL-6, IL-10 and TNF-α in plasma were determined using enzyme immunoassay method (ELISA). Factor analysis using the program SPSS for Windows, version 21.0 was performed. Results. In allergic BA (ABA) factor analysis identified 3 factors that characterize the role of IL-6 in the development of both the key characteristics of BA (bronchial obstruction), and key features of CKD (eGFR), as well as the failure of the system of regulation of proinflammatory/anti-inflammatory cytokines balance. In nonallergic BA (NABA) factor analysis identified 4 factors that characterize in particular the influence of the TNF-α expression on the severity of the disease and the value of eGFR. The more severe BA the greater the decrease in eGFR. Conclusion. Possible pathogenetic relationship between the expression of key proinflammatory cytokines (IL-6, TNF-α) and glomerular filtration rate in BA is discussed. In ABA the IL-6 expression has probably common pathogenetic value when forming bronchial obstruction and CKD, on the other hand in NABA the TNF-α overexpression has likely common pathogenetic value when forming bronchial obstruction (possibly due to influence on bronchial remodeling) and CKD.

Bronchial Smooth Muscle Remodeling in Nonsevere Asthma.

Increased bronchial smooth muscle (BSM) mass is a key feature of airway remodeling that classically distinguishes severe from nonsevere asthma. Proliferation of BSM cells involves a specific mitochondria-dependent pathway in individuals with severe asthma. However, BSM remodeling and mitochondrial biogenesis have not been examined in nonsevere asthma. We aimed to assess whether an increase in BSM mass was also implicated in nonsevere asthma and its relationship with mitochondria and clinical outcomes. We enrolled 34 never-smoker subjects with nonsevere asthma. In addition, we recruited 56 subjects with nonsevere asthma and 19 subjects with severe asthma as comparative groups (COBRA cohort [Cohorte Obstruction Bronchique et Asthme; Bronchial Obstruction and Asthma Cohort; sponsored by the French National Institute of Health and Medical Research, INSERM]). A phenotypic characterization was performed using questionnaires, atopy and pulmonary function testing, exhaled nitric oxide measurement, and blood collection. Bronchial biopsy specimens were processed for immunohistochemistry and electron microscopy analysis. After BSM remodeling assessment, subjects were monitored over a 12-month period. We identified characteristic features of remodeling (BSM area >26.6%) and increased mitochondrial number within BSM in a subgroup of subjects with nonsevere asthma. The number of BSM mitochondria was positively correlated with BSM area (r = 0.78; P < 0.001). Follow-up analysis showed that subjects with asthma with high BSM had worse asthma control and a higher rate of exacerbations per year compared with subjects with low BSM. This study reveals that BSM remodeling and mitochondrial biogenesis may play a critical role in the natural history of nonsevere asthma (Mitasthme study). Clinical trial registered with www.clinicaltrials.gov (NCT00808730).

Obstructive Sleep Apnoea Modulates Airway Inflammation and Remodelling in Severe Asthma.

BackgroundObstructive sleep apnoea (OSA) is frequently observed in severe asthma but the causal link between the 2 diseases remains hypothetical. The role of OSA-related systemic and airway neutrophilic inflammation in asthma bronchial inflammation or remodelling has been rarely investigated. The aim of this study was to compare hallmarks of inflammation in induced sputum and features of airway remodelling in bronchial biopsies from adult patients with severe asthma with and without OSA.Materials and MethodsAn overnight polygraphy was performed in 55 patients referred for difficult-to-treat asthma, who complained of nocturnal respiratory symptoms, poor sleep quality or fatigue. We compared sputum analysis, reticular basement membrane (RBM) thickness, smooth muscle area, vascular density and inflammatory cell infiltration in bronchial biopsies.ResultsIn total, 27/55 patients (49%) had OSA diagnosed by overnight polygraphy. Despite a moderate increase in apnoea-hypopnoea index (AHI; 14.2±1.6 event/h [5–35]), the proportion of sputum neutrophils was higher and that of macrophages lower in OSA than non-OSA patients, with higher levels of interleukin 8 and matrix metalloproteinase 9. The RBM was significantly thinner in OSA than non-OSA patients (5.8±0.4 vs. 7.8±0.4 μm, p<0.05). RBM thickness and OSA severity assessed by the AHI were negatively correlated (rho = -0.65, p<0.05). OSA and non-OSA patients did not differ in age, sex, BMI, lung function, asthma control findings or treatment.ConclusionMild OSA in patients with severe asthma is associated with increased proportion of neutrophils in sputum and changes in airway remodelling.

The extracellular matrix of the lung and airway responsiveness in asthma

The extracellular matrix is the main determinant of the structure and of mechanical behaviour of the lung. The extracellular matrix is also responsible for the mechanical interdependence between airway and parenchyma due to the alveolar attachments to the airways. Asthma is characterized by bronchial hyperresponsiveness, airway remodelling and inflammation, and an altered extracellular matrix may play a role in all these functional and structural abnormalities. The excessive airway narrowing observed in asthma may be related to the altered viscoelastic properties of lung parenchyma and airway wall, determining a decrease in the mechanical load opposing the airways' smooth muscle contraction. Indeed, an altered extracellular matrix deposition in asthma in humans, has been demonstrated. In addition, in the asthmatic lung, the matrix seems to contribute to airway inflammation, airway remodelling, and to those alterations of the smooth muscle function of the airway and morphology typical of asthma.

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

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

High mobility group box 1-induced epithelial mesenchymal transition in human airway epithelial cells.

Epithelial–mesenchymal transition (EMT) is implicated in bronchial remodeling and loss of lung function in chronic inflammatory airway diseases. Previous studies showed the involvement of the high mobility group box 1 (HMGB1) protein in the pathology of chronic pulmonary inflammatory diseases. However, the role of HMGB1 in EMT of human airway epithelial cells is still unclear. In this study, we used RNA sequencing to show that HMGB1 treatment regulated EMT-related gene expression in human primary-airway epithelial cells. The top five upregulated genes were SNAI2, FGFBP1, VIM, SPARC (osteonectin), and SERPINE1, while the downregulated genes included OCLN, TJP1 (ZO-1), FZD7, CDH1 (E-cadherin), and LAMA5. We found that HMGB1 induced downregulation of E-cadherin and ZO-1, and upregulation of vimentin mRNA transcription and protein translation in a dose-dependent manner. Additionally, we observed that HMGB1 induced AKT phosphorylation, resulting in GSK3β inactivation, cytoplasmic accumulation, and nuclear translocation of β-catenin to induce EMT in human airway epithelial cells. Treatment with PI3K inhibitor (LY294006) and β-catenin shRNA reversed HMGB1-induced EMT. Moreover, HMGB1 induced expression of receptor for advanced glycation products (RAGE), but not that of Toll-like receptor (TLR) 2 or TLR4, and RAGE shRNA inhibited HMGB1-induced EMT in human airway epithelial cells. In conclusion, we found that HMGB1 induced EMT through RAGE and the PI3K/AKT/GSK3β/β-catenin signaling pathway.

Expression of M3 acetylcholine receptor in asthmatic mice and bronchial airway remodeling prediction.

This study aimed to investigate the role of M3 acetylcholine receptor (M3-AChR) expression in airway remodeling. Additionally, we aimed to evaluate the effects of ipratropium bromide solution inhaled in an early phase of asthma on airway remodeling in ovalbumin (OVA)-sensitized and challenged mice. Thirty BALB/c mice were divided into three groups, namely, control group (saline sensitized/challenged mice), asthma group (OVA sensitized/challenged mice), and treatment group (OVA sensitized/challenged mice treated by ipratropium bromide). Pathological changes were detected by histological staining in the bronchopulmonary tissue of mice. WAt/Pbm (the airway wall area /basement membrane perimeter) ratio of the asthma group (25.37 ± 4.25) increased significantly (P < 0.05) when compared with that of the control (12.89 ± 1.71) and treatment group (15.82 ± 2.91). WAm/Pbm (smooth muscle wall area / basement membrane perimeter) ratio of the asthma group (7.58 ± 2.16) increased significantly (P < 0.05) when compared with that of the control (2.55 ± 0.72) and treatment group (3.36 ± 1.69). M3-AChR concentration increased in the treatment group (29.24 ± 3.59) and was significantly different (P < 0.05) from that of the control group (25.50 ± 1.83). During asthma treatment, SAMA can alleviate airway remodeling in murine model by lessening the thickness of bronchial walls and inhibiting the proliferation of smooth muscle cells. There were no obvious changes in M3-AChR density in the murine model of asthma characterized by airway remodeling. However, ipratropium bromide may up-regulate the expression of M3-AChR in bronchial walls of asthmatic murine model.

Morphometric characteristics of the bronchial tree in smokers with and without chronic obstructive pulmonary disease

To reveal the tissue, cellular, and molecular predictors leading to the development of chronic obstructive pulmonary disease (COPD) in smokers on the basis of a morphometric analysis of bronchial biopsy specimens. A cross-sectional study was conducted in 115 smokers aged 40 to 60 years (58.3±3.24 years) with a male predominance of 90.9%. Morphological examination of bronchial biopsy specimens was first made in the smoking patients with and without COPD. The smokers with COPD versus those without this condition were found to have a statistically significant increase in a number of indicators: the specific volume (SV) of the surface epithelium (p=0.017), SV of basal epitheliocytes (p=0.008), the height of the epithelium (p=0.001), and the thickness of the basal membrane (p=0.006) due to impaired regeneration processes in the bronchial epithelium and to fibrosis of the lamina propria of the bronchi with a concurrent increase in the total number of fibroblasts. The group of smokers with COPD, unlike the comparison group, showed signs of vascular remodeling and microcirculatory disorders as the increased connective tissue volumetric density of the lamina propria of the bronchi with predominant perivascular localization. This was followed by reductions in the relative volume of capillaries (p=0.016), in the SV of micropinocytic vesicles (p=0.005), and the size of Weibel-Palade bodies (p=0.004) in the endotheliocytes. In the COPD patients, the total density of cell infiltrate per mm2 of the lamina propria of the bronchi was statistically significantly (p<0.001) greater than that in the comparison group at the expense of neutrophils, lowly and moderately granulated basophils, macrophages, plasma cells with a simultaneous rise in their interepithelial forms. Compensatory structural changes without signs of bronchial wall remodeling were recorded in the smokers without signs of bronchial disease. The smokers with the examined nosological entity were observed to have morphological signs of hemodynamic disorders, as well as perivascular fibrosis, atrophy, and squamous cell metaplasia of the bronchial epithelial lining.

Endobronchial Ultrasound Reliably Quantifies Airway Smooth Muscle Remodeling in an Equine Asthma Model.

Endobronchial ultrasonography (EBUS) revealed differences in the thickness of the layer representing subepithelial tissues (L2) between human asthmatics and controls, but whether this measurement correlates with airway smooth muscle (ASM) remodeling in asthma is unknown. In this study, we sought to determine the ability of EBUS to predict histological ASM remodeling in normal and equine asthmatic airways. We studied 109 isolated bronchi from the lungs of 13 horses. They underwent EBUS examination using a 30 MHz radial probe before being processed for histology. ASM remodeling parameters were evaluated in EBUS images (L2 thickness, L2 area, L2 area/internal perimeter [Pi] and L2 area/Pi2) and histological cuts (ASM area/Pi2), and compared. EBUS was then performed ex vivo on the lungs of 4 horses with heaves, an asthma-like condition of horses, and 7 controls to determine whether central bronchial remodeling could be detected with this technique. An optimized approach was developed based on data variability within airways, subjects, and groups, and then validated in 7 horses (3 controls, 4 with heaves) that underwent EBUS in vivo. L2 area was significantly associated to ASM area in isolated lungs (p<0.0001), in the absence of significant bias related to the airway size. Bronchial size significantly affected EBUS ASM-related parameters, except for L2 area/Pi2. L2 area/Pi2 was increased in the airways of asthmatic horses compared to controls, both ex vivo and in vivo (p<0.05). Bronchial histology confirmed our findings (AASM/Pi2 was increased in asthmatic horses compared to controls, p<0.05). In both horses with heaves and controls, L2 was composed of ASM for the outer 75% of its thickness and by ECM for the remaining inner 25%. In conclusion, EBUS reliably allows assessment of asthma-associated ASM remodeling of central airways in a non-invasive way.

Platelets from Asthmatic Individuals Show Less Reliance on Glycolysis.

Asthma, a chronic inflammatory airway disease, is typified by high levels of TH2-cytokines and excessive generation of reactive nitrogen and oxygen species, which contribute to bronchial epithelial injury and airway remodeling. While immune function plays a major role in the pathogenesis of the disease, accumulating evidence suggests that altered cellular metabolism is a key determinant in the predisposition and disease progression of asthma. Further, several studies demonstrate altered mitochondrial function in asthmatic airways and suggest that these changes may be systemic. However, it is unknown whether systemic metabolic changes can be detected in circulating cells in asthmatic patients. Platelets are easily accessible blood cells that are known to propagate airway inflammation in asthma. Here we perform a bioenergetic screen of platelets from asthmatic and healthy individuals and demonstrate that asthmatic platelets show a decreased reliance on glycolytic processes and have increased tricarboxylic acid cycle activity. These data demonstrate a systemic alteration in asthma and are consistent with prior reports suggesting that oxidative phosphorylation is more efficient asthmatic individuals. The implications for this potential metabolic shift will be discussed in the context of increased oxidative stress and hypoxic adaptation of asthmatic patients. Further, these data suggest that platelets are potentially a good model for the monitoring of bioenergetic changes in asthma.

Evaluation of vascular endothelial growth factor-A and Endostatin levels in induced sputum and relationship to bronchial hyperreactivity in patients with persistent allergic rhinitis monosensitized to house dust

Studies about the pathogenesis of bronchial hyperreactivity (BHR) in patients with persistent allergic rhinitis (PAR) and its relationship with lower airway remodeling are extremely limited. This study evaluated bronchial vascular remodeling via the measurement of angiogenic factor, vascular endothelial growth factor-A (VEGF-A), and anti-angiogenic factor, Endostatin, and evaluated their relationship with BHR in patients with PAR. The study group consisted of 30 patients with PAR monosensitized to house dust mites and 14 non-allergic healthy controls. All subjects underwent induced sputum and methacholine (M) bronchial provocation tests. VEGF-A and Endostatin levels were measured by ELISA in induced sputum supernatants. The percentages of eosinophils in induced sputum were significantly increased in patients with PAR compared with healthy controls. There were no significant differences between patients with PAR and healthy controls in terms of levels of VEGF (37.9pg/ml, min-max: 5-373pg/ml vs. 24.9, min-max: 8-67pg/ml, p=0.8 respectively), Endostatin (532.5pg/ml, min-max: 150-2125pg/ml vs. 644, min-max: 223-1123pg/ml, p=0.2 respectively) and VEGF/Endostatin ratio (0.057 vs. 0.045, p=0.8 respectively). In addition, there were no significant differences between patients who are BHR positive (n=8), or negative to M (n=22) in terms of levels of VEGF, Endostatin and VEGF/Endostatin ratio and no correlations among value of PD20 to M and levels of VEGF, Endostatin and VEGF/Endostatin ratio. We conclude that VEGF-A and Endostatin did not differ between patients with PAR and healthy controls regardless of BHR to M.

Characteristics of IL-25 and allergen-induced airway fibrosis in a murine model of asthma.

Interleukin (IL)-25 has been implicated in the pathogenesis of human asthma by inducing a Th2 cytokine response, but its possible role in the development of airway remodelling is less clear. We developed a murine surrogate of chronic airway inflammation induced by intranasal application of IL-25 alone. Comparison was with the 'classical' surrogate of ovalbumin (OVA) intranasal instillation into previously sensitized animals. Airway fibrotic biomarkers were analysed by immunohistochemistry and enzyme-linked immunosorbent assay. Additionally, proliferation assay and real-time polymerase chain reaction analysis were performed to assess IL-25's effects on primary human bronchial fibroblasts in vitro. In Balb/c mice, intranasal instillation of IL-25 alone induced florid airway fibrosis, including increased lay down of extracellular matrix proteins such as collagen I, III, V and fibronectin, increased numbers of fibroblasts/myofibroblasts, a profibrotic imbalance in matrix metalloproteinase/tissue inhibitor of metalloproteinase production and increased expression of profibrotic mediators including connective tissue growth factor and transforming growth factor-β1. These changes broadly reproduced those seen with classical intranasal OVA challenge in OVA-sensitized animals. Furthermore, IL-25 induced proliferation and expression of collagen I and III and smooth muscle α-actin in primary human lung fibroblasts. We conclude that chronic exposure of the airways to IL-25 alone is sufficient to cause functionally relevant airway remodelling, with the corollary that targeting of IL-25 may attenuate bronchial remodelling and fibrosis in human asthmatics.

House dust mites induce proliferation of severe asthmatic smooth muscle cells via an epithelium-dependent pathway.

Asthma is a frequent airway disease, and asthma control determinants have been associated with indoor allergen sensitization. The most frequent allergens are house dust mites (HDM), which act in vivo on the bronchial epithelial layer. Severe asthma has also been associated with bronchial remodeling and more specifically with increased mass of bronchial smooth muscle (BSM). However, the relationship between HDM stimulation of the bronchial epithelial layer and BSM remodeling is unknown. To evaluate whether epithelial stimulation with HDM induces BSM cell proliferation in subjects with severe asthma. A total of 22 subjects with severe asthma and 27 subjects with no asthma were recruited. We have developed an in vitro culture model combining an epithelium layer in air-liquid interface (ALI) interacting with BSM. We assessed BSM proliferation using BrdU incorporation. We explored the role of epithelium-derived mediators using reverse-transcriptase polymerase chain reaction (RT-PCR) and ELISA in vitro and in vivo. Finally, leukotrienes receptor expression was assessed in vitro by flow cytometry and RT-PCR and ex vivo by laser microdissection and RT-PCR. We found that epithelial stimulation by HDM selectively increased the proliferation of asthmatic BSM cells and not that of nonasthmatic cells. The mechanism involved epithelial protease-activated receptor-2-dependent production of leukotrienes C4 associated with an overexpression of leukotrienes receptor CysLTR1 by asthmatic BSM cells in vitro and ex vivo. This work demonstrates the selective role of HDM on BSM remodeling in patients with severe asthma and points out different therapeutic targets at epithelial and smooth muscle levels.

House dust mites induce asthmatic smooth muscle cell proliferation through epithelium- and leukotrienes-dependent pathways

Introduction Asthma is a very frequent airway disease that affects 5 to 20% of the whole population worldwide. Whereas the mortality of asthma has been dramatically decreased within the last 10 years, uncontrolled asthma still induces major consequences on morbidity, quality of life, and economic burden. Asthma control determinants have been associated to indoor allergens sensitization. The most frequent indoor allergen is the house dust mites (HDM), which act in vivo on bronchial epithelial layer. Uncontrolled asthma has also been associated with bronchial remodeling and more specifically to the increased mass of bronchial smooth muscle (BSM). It is now well admitted that, BSM remodeling is related with an increase of asthmatic BSM cell proliferation both in vitro and in vivo. However, the relationship between HDM stimulation of the bronchial epithelial layer and BSM remodeling is unknown. Methods We have developed an in vitro culture model of epithelium in air liquid interface (ALI) and BSM interaction. We assessed BSM proliferation using BrdU incorporation. We explored the role of leukotrienes in such a proliferation. We assessed the expression of enzymes involved in the leukotrienes synthesis pathway using RT-PCR. Leukotrienes release was assessed by Elisa in vitro on epithelial cell supernatant and in vivo in mouse broncho-alveolar lavage fluid. Finally, leukotrienes receptor expression was assessed both in vitro by flow cytometry and ex vivo by laser microdissection and RT-PCR. Results We found that epithelial stimulation by HDM increased the proliferation of asthmatic BSM cells and not that of non-asthmatics. The mechanisms involved an epithelial production of leukotrienes C4 and an over-expression of leukotrienes receptor CysLTR1 by asthmatic BSM cells both in vitro and in vivo. Conclusions This work demonstrates the role of HDM on BSM remodeling that occurs only in asthmatic patients and highlights different therapeutic targets at both epithelial and smooth muscle levels.

Bronchial smooth muscle increase proliferation is associated to p53 dysfunction in asthma

Introduction Asthma is a frequent respiratory disease characterized by bronchial hyperresponsiveness, inflammation and remodeling. Bronchial remodeling corresponds to structural modification of the bronchial wall. Increase of smooth muscle mass is a crucial feature of such a remodeling in asthma. Indeed, it correlates with the decrease in lung function and bronchial thermoplasty, which is supposed to decrease BSM mass, was associated with a decrease in exacerbation rate. The mechanisms of such an increased BSM mass are complex and remain controversial. However, increased proliferation of asthmatic BSM cells has been proposed and largely documented both in vitro and in vivo. We previously demonstrated that such an increased BSM cell proliferation involved an increased mitochondrial biogenesis and mitochondrial mass through the increase of PGC-1α and Tfam expression. Major tumor suppressor protein p53 is a key cell regulator involved in cell proliferation and has also been implicated in mitochondrial biogenesis. However, the role of p53 in BSM cell proliferation and mitochondrial biogenesis has not been investigated so far. We thus hypothesized that, p53 can modulate BSM cell mitochondrial biogenesis and proliferation and that this modulation is disrupted in asthmatic cells. Methods Using shRNA lentivirus targeting p53, we assessed the role of p53 in both asthmatic and control BSM cells proliferation using both BrdU and cell counting. We analyzed the effect of the down-regulation of p53 protein on the regulation of p21, Bax, TFAM and PGC-1α mRNA. Finally, we assessed the expression of p53 in vitro using flow cytometry and western blot but also ex vivo using laser microdissection and RT-PCR. Results We found that, p53 is unable to inhibit the transcription of Tfam and PGC1α in asthmatic BSM. As a consequence, p53 cannot slow down the increased mitochondrial biogenesis and the subsequent increased proliferation of asthmatic BSM cells. We also found that p53 expression was increased in asthmatic BSM, which was related with a loss of Mdm2 activation by p53. Conclusions In conclusion, this work highlights p53 as a new potential therapeutic target against BSM remodeling in asthma.

Роль факторов роста и провоспалительных цитокинов в процессе ремоделлинга слизистой оболочки бронхов при респираторном дистресс-синдроме новорожденных

Роль факторов роста и провоспалительных цитокинов в процессе ремоделлинга слизистой оболочки бронхов при респираторном дистресс-синдроме новорожденных

Undifferentiated bronchial fibroblasts derived from asthmatic patients display higher elastic modulus than their non-asthmatic counterparts.

During asthma development, differentiation of epithelial cells and fibroblasts towards the contractile phenotype is associated with bronchial wall remodeling and airway constriction. Pathological fibroblast-to-myofibroblast transition (FMT) can be triggered by local inflammation of bronchial walls. Recently, we have demonstrated that human bronchial fibroblasts (HBFs) derived from asthmatic patients display some inherent features which facilitate their FMT in vitro. In spite of intensive research efforts, these properties remain unknown. Importantly, the role of undifferentiated HBFs in the asthmatic process was systematically omitted. Specifically, biomechanical properties of undifferentiated HBFs have not been considered in either FMT or airway remodeling in vivo. Here, we combine atomic force spectroscopy with fluorescence microscopy to compare mechanical properties and actin cytoskeleton architecture of HBFs derived from asthmatic patients and non-asthmatic donors. Our results demonstrate that asthmatic HBFs form thick and aligned ‘ventral’ stress fibers accompanied by enlarged focal adhesions. The differences in cytoskeleton architecture between asthmatic and non-asthmatic cells correlate with higher elastic modulus of asthmatic HBFs and their increased predilection to TGF-β-induced FMT. Due to the obvious links between cytoskeleton architecture and mechanical equilibrium, our observations indicate that HBFs derived from asthmatic bronchi can develop considerably higher static tension than non-asthmatic HBFs. This previously unexplored property of asthmatic HBFs may be potentially important for their myofibroblastic differentiation and bronchial wall remodeling during asthma development.

Effect of angioprotectors on morphological changes in the lungs in COPD model

The aim of this study was to investigate morphological changes in the bronchi and the pulmonary arteries in the natural course of COPD and under treatment with angioprotective agents. Methods. COPD was modelled in rats by intermittent nitrogen dioxide inhalations for 60 days. Agents with angioprotective activity, such as rosuvastatin or sulodexide, were administered after the 30 th day of the exposure. Histological examination included morphometry. Results. The vascular wall thickness due to the media and the intima area enlargement was seen during COPD development without change in the vessel lumen. The Intima / media index also increased that is a typical sign of atherosclerotic lesion of the vascular wall. Pulmonary arteries diameter and the lumen size reduced under the treatment with sulodexide and rosuvastatin without any change in the vascular wall thickness but the intima / media index approached to the normal value. Conclusion. Ventilatory disorder progression in COPD is thought to be due to bronchial wall and lung remodeling such as sclerosis of the bronchial smooth muscle layer and occurrence of panacinar emphysema. Rosuvastatin improved pulmonary circulation and reduced lymphocytic infiltration of the large bronchi wall and the interalveolar septae. Positive effect of sulodexide on the pulmonary artery wall could be related to the presence of highly active heparin fraction in the drug structure that can improve the endothelial cell function. Agents with antithrombotic and angioprotective activity could slow COPD progression and of severe complication development.