Smoking effect on the ultrastructural properties of cultured lung myofibroblasts.

This study aimed at an ultrastructural characterization of myofibroblasts cultured from different compartments of lung from never-smokers and smokers with or without COPD. In addition, we evaluated the expression of alpha smooth muscle actin (α-SMA), a marker for myofibroblasts, and contractile properties. Stromal cells cultured from central and corresponding peripheral or only from peripheral lung of never-smokers, smokers without COPD and COPD patients were analyzed by transmission electron microscopy (TEM), immunoelectron microscopy (IEM), Western analysis and/or by collagen gel contraction assay. TEM revealed that myofibroblasts cultured from smokers and COPD had less prominent intracellular actin filaments. We also examined fibronexus (FNX), which is a typical ultrastructural feature of myofibroblasts, and observed that patients with COPD more frequently had tandem-like FNX as compared to other samples. Western analysis showed that the samples derived from the central lung of never-smokers expressed higher levels of α-SMA than those of smokers and COPD patients. Cells from central lung were less contractile than those from peripheral lung. We conclude that myofibroblasts have variable ultrastructural and functional properties based on their localization in the lung and, moreover, these properties are affected by both smoking history and COPD.

Cadherin-11-mediated adhesion of macrophages to myofibroblasts establishes a profibrotic niche of active TGF-ß.

Macrophages contribute to the activation of fibroblastic cells into myofibroblasts, which secrete collagen and contract the collagen matrix to acutely repair injured tissue. Persistent myofibroblast activation leads to the accumulation of fibrotic scar tissue that impairs organ function. We investigated the key processes that turn acute beneficial repair into destructive progressive fibrosis. We showed that homotypic cadherin-11 interactions promoted the specific binding of macrophages to and persistent activation of profibrotic myofibroblasts. Cadherin-11 was highly abundant at contacts between macrophages and myofibroblasts in mouse and human fibrotic lung tissues. In attachment assays, cadherin-11 junctions mediated specific recognition and strong adhesion between macrophages and myofibroblasts. One functional outcome of cadherin-11-mediated adhesion was locally restricted activation of latent transforming growth factor-ß (TGF-ß) between macrophage-myofibroblast pairs that was not observed in cocultures of macrophages and myofibroblasts that were not in contact with one another. Our data suggest that cadherin-11 junctions maintain latent TGF-ß-producing macrophages and TGF-ß-activating myofibroblasts in close proximity to one another. Inhibition of homotypic cadherin-11 interactions could be used to cause macrophage-myofibroblast separation, thereby destabilizing the profibrotic niche.

Mucin-1 correlates with survival, smoking status, and growth patterns in lung adenocarcinoma.

Mucin-1 (MUC1) affects cancer progression in lung adenocarcinoma, and its aberrant expression pattern has been correlated with poor tumor differentiation and impaired prognosis. In this study, the immunohistochemical expression of MUC1 and Mucin-4 (MUC4) was analyzed in a series of 106 surgically operated stage I-IV pulmonary adenocarcinomas. MUC1 immunohistochemistry was evaluated according to the Nagai classification, and the immunohistochemical profile of the tumors was correlated with detailed clinical and histological data. The effect of cigarette smoke on MUC1 expression in lung cancer cell lines was examined using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunoelectron microscopy (IEM). In contrast to the normal apical localization of MUC1, a basolateral and cytoplasmic (depolarized) MUC1 expression pattern was frequently encountered in the high-grade subtypes, i.e., solid predominant adenocarcinoma and the cribriform variant of acinar predominant adenocarcinoma (p < 0.001), and was rarely observed in tumors containing a non-predominant lepidic component (p < 0.001). Furthermore, the altered staining pattern of MUC1 correlated with stage (p = 0.002), reduced overall survival (p = 0.031), and was associated with smoking (p < 0.001). When H1650 adenocarcinoma cells were exposed to cigarette smoke and analyzed by RT-qPCR and IEM, the levels of the MUC1 transcript and protein were elevated (p = 0.042). In conclusion, MUC1 participates in the pathogenesis of lung adenocarcinoma and associates with smoking both in vitro and in vivo. In lung adenocarcinoma, depolarized MUC1 protein expression correlated with histological growth patterns, stage, and patient outcome.

Pirfenidone and nintedanib modulate properties of fibroblasts and myofibroblasts in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an incurable lung disease with a poor prognosis. Fibroblasts and myofibroblasts are the key cells in the fibrotic process. Recently two drugs, pirfenidone and nintedanib, were approved for clinical use as they are able to slow down the disease progression. The mechanisms by which these two drugs act in in vitro cell systems are not known. The aim of this study was therefore to examine the effects of pirfenidone and nintedanib on fibroblasts and myofibroblasts structure and function established from patients with or without IPF. METHODS: Stromal cells were collected and cultured from control lung (n = 4) or IPF (n = 7). The cells were treated with pirfenidone and/or nintedanib and the effect of treatment was evaluated by measuring cell proliferation, alpha smooth muscle actin (α-SMA) and fibronectin expression by Western analysis and/or immunoelectron microscopy, ultrastructural properties by transmission electron microscopy and functional properties by collagen gel contraction and invasion assays. RESULTS: Both pirfenidone and nintedanib reduced in vitro proliferation of fibroblastic cells in a dose dependent manner. The number of cells from control lung was reduced to 47 % (p = 0.04) and of IPF cells to 42 % (p = 0.04) by 1 mM pirfenidone and correspondingly to 67 % (p = 0.04) and 68 % (p = 0.04), by 1 µM nintedanib. If both drugs were used together, a further reduced proliferation was observed. Both pirfenidone and nintedanib were able to reduce the amount of α-SMA and the myofibroblastic appearance although the level of reduction was cell line dependent. In functional assays, the effect of both drugs was also variable. CONCLUSIONS: We conclude that the ultrastructure and function of fibroblasts and myofibroblasts are affected by pirfenidone and nintedanib. Combination of the drugs reduced cell proliferation more than either of them individually. Human lung derived cell culture systems represent a potential platform for screening and testing drugs for fibrotic diseases.

Stromal cells can be cultured and characterized from diagnostic bronchoalveolar fluid samples obtained from patients with various types of interstitial lung diseases.

Increased proliferation of stromal cells is a typical feature encountered in several lung diseases. The objective of this study was to evaluate the success of standardized process for culturing stromal cells from small volumes of diagnostic bronchoalveolar lavage (BAL) fluid samples collected from various patients and to characterize the cultured cells. Small volumes (average 15 mL) of BAL fluid samples were collected from 98 patients who underwent bronchoscopy and BAL for diagnostic purposes. The cells were cultured in vitro and characterized by immunohistochemistry, electron microscopy, flow cytometry and differentiation tests. Cells could be cultured from 62% of samples with the success rate varying with the disease (p = 0.003). Cultures from samples of the patients with idiopathic pulmonary fibrosis, non-specific interstitial pneumonia, connective tissue disorder associated interstitial lung disease and allergic alveolitis had a higher success rate than samples derived from control lung (p < 0.001, 0.03, 0.03 and 0.044, respectively). Smokers had a higher success rate compared with non-smokers (p = 0.035). The cultured cells were fibroblasts or myofibroblasts, but shared also similarities with progenitor-type cells. The study shows that mesenchymal cells can be cultured and studied from small volumes of diagnostic BAL fluid samples from patients with several different types of lung diseases.

Lung cancer-associated myofibroblasts reveal distinctive ultrastructure and function.

BACKGROUND: Cancer-associated stromal cells interact with carcinoma cells and thus participate in tumor growth. Our aim was to characterize the ultrastructure and contractile properties of stromal cells in collagen gel cultured from lung cancer of various histological types and from tumor-free lung. METHODS: Cells cultured from lung cancer (13 adenocarcinomas, six squamous cell carcinomas, one adenosquamous carcinoma, and one pleomorphic carcinoma) and tumor-free lung were analyzed by transmission electron microscopy and three-dimensional collagen gel contraction assays. The expression of α-smooth muscle actin (α-SMA), a recognized myofibroblast marker, was examined by immunoelectron microscopy from individual cells and by Western blotting from the whole cultured cell population. RESULTS: According to their ultrastructure, the cell lines were composed of fibroblastic and myofibroblastic cells. In electron microscopy, cells of lung cancer exhibited more myofibroblastic features displaying higher amounts of actin belts (p = 0.057) and α-SMA labeling (p = 0.010) than cells from tumor-free lung. Myofibroblasts cultured from lung cancer of smokers expressed less α-SMA labeling (p = 0.013) than counterparts from nonsmokers. Western blotting revealed that cancer-associated fibroblasts expressed more α-SMA (p = 0.006) than cells from tumor-free lung, whereas cells from tumor-free central lung of smokers showed less α-SMA (p = 0.039) than counterparts from nonsmokers. Cells cultured from cancer contracted more in collagen gel than those from tumor-free lung. The contractile capacity in collagen gel correlated with the frequency of extracellular component of fibronexus by transmission electron microscopy. CONCLUSIONS: Lung cancer-associated myofibroblasts are different both ultrastructurally and functionally when compared with cells cultured from tumor-free lung. Smoking altered myofibroblastic phenotype, regardless of their origin.

Myofibroblast expression in airways and alveoli is affected by smoking and COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by structural changes in alveoli and airways. Our aim was to analyse the numbers of alpha-smooth muscle actin (α-SMA) positive cells, as a marker of myofibroblasts, in different lung compartments in non-smokers and smokers with normal lung function or COPD. METHODS: α-SMA, tenascin-C (Tn-C) and EDA-fibronectin in alveolar level and airways were assayed by immunohistochemistry and quantified by image analysis. Immunohistochemical findings were correlated with clinical data. α-SMA protein was also analysed by Western blotting from fibroblastic cells cultured from peripheral lung of non-smokers, smokers without COPD and smokers with COPD. RESULTS: In many cases, the endings of the detached alveolar walls were widened, the structures of which were named as widened alveolar tips. Widened alveolar tips contained α-SMA positive cells, which were obviously myofibroblasts. There were less alveolar tips containing positive cells for α-SMA in alveoli and α-SMA positive cells in bronchioles in smokers and in COPD compared to non-smokers. The quantity of α-SMA positive cells was increased in bronchi in COPD. Tn-C was elevated in bronchi in COPD and smokers' lung. The α-SMA protein level was 1.43-fold higher in stromal cells cultured from non-smokers than in those of smokers. CONCLUSIONS: Myofibroblasts are localized variably in normal and diseased lung. This indicates that they have roles in both regeneration of lung and pathogenesis of COPD. The widened alveolar tips, these newly characterized histological structures, seemed to be the source of myofibroblasts at the alveolar level.

Myofibroblasts in interstitial lung diseases show diverse electron microscopic and invasive features.

The characteristic features of myofibroblasts in various lung disorders are poorly understood. We have evaluated the ultrastructure and invasive capacities of myofibroblasts cultured from small volumes of diagnostic bronchoalveolar lavage (BAL) fluid samples from patients with different types of lung diseases. Cells were cultured from samples of BAL fluid collected from 51 patients that had undergone bronchoscopy and BAL for diagnostic purposes. The cells were visualized by transmission electron microscopy and immunoelectron microscopy to achieve ultrastructural localization of alpha-smooth muscle actin (α-SMA) and fibronectin. The levels of α-SMA protein and mRNA and fibronectin mRNA were measured by western blot and quantitative real-time reverse transcriptase polymerase chain reaction. The invasive capacities of the cells were evaluated. The cultured cells were either fibroblasts or myofibroblasts. The structure of the fibronexus, and the amounts of intracellular actin, extracellular fibronectin and cell junctions of myofibroblasts varied in different diseases. In electron and immunoelectron microscopy, cells cultured from interstitial lung diseases (ILDs) expressed more actin filaments and α-SMA than normal lung. The invasive capacity of the cells obtained from patients with idiopathic pulmonary fibrosis was higher than that from patients with other type of ILDs. Cells expressing more actin filaments had a higher invasion capacity. It is concluded that electron and immunoelectron microscopic studies of myofibroblasts can reveal differential features in various diseases. An analysis of myofibroblasts cultured from diagnostic BAL fluid samples may represent a new kind of tool for diagnostics and research into lung diseases.

Effect of alpha-linolenic acid-rich Camelina sativa oil on serum fatty acid composition and serum lipids in hypercholesterolemic subjects.

Camelina sativa-derived oil (camelina oil) is a good source of alpha-linolenic acid. The proportion of alpha-linolenic acid in serum fatty acids is associated with the risk of cardiovascular diseases. We studied the effects of camelina oil on serum lipids and on the fatty acid composition of total lipids in comparison to rapeseed and olive oils in a parallel, double-blind setting. Sixty-eight hypercholesterolemic subjects aged 28 to 65 years were randomly assigned after a 2-week pretrial period to 1 of 3 oil groups: camelina oil, olive oil, and rapeseed oil. Subjects consumed daily 30 g (actual intake, approximately 33 mL) of test oils for 6 weeks. In the camelina group, the proportion of alpha-linolenic acid in fatty acids of serum lipids was significantly higher (P <.001) compared to the 2 other oil groups at the end of the study: 2.5 times higher compared to the rapeseed oil group and 4 times higher compared to the olive oil group. Respectively the proportions of 2 metabolites of alpha-linolenic acid (eicosapentaenoic and docosapentaenoic acids) increased and differed significantly in the camelina group from those in other groups. During the intervention, the serum low-density lipoprotein (LDL) cholesterol concentration decreased significantly by 12.2% in the camelina oil group, 5.4% in the rapeseed oil group, and 7.7% in the olive oil group. In conclusion, camelina oil significantly elevated the proportions of alpha-linolenic acid and its metabolites in serum of mildly or moderately hypercholesterolemic subjects. Camelina oil's serum cholesterol-lowering effect was comparable to that of rapeseed and olive oils.