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Introduction: Endobronchial foreign body aspiration is not common in adults, but it is a life-threatening event. Recurrent pneumonias by chronic retention of foreign body often lead to initial medical presentation of the patient. However, lymphoplasmacellular bronchitis with adenomatous hyperplasia and squamous epithelium metaplasia with complete or partial blockage of lobar bronchus mimicking lung tumor is rare in literature, and this particular condition is often misdiagnosed. Case presentation: we report our experience in the diagnostic and management of two elderly patients with recurrent pneumonia, admitted in hospital for further examination. In both patients, with no history of aspiration, the cherry pit was detected during bronchoscopy and recanalization with flexible cryoprobe, surrounded by purulent secretion, occluding completely the right upper lobe in the first case, and partially the left lower lobe associated with persistent actinomycosis in the second case, with signs of local inflammation, bronchial adenomatous hyperplasia mimicking lung tumor at initial bronchoscopic examination. Histology showed a lymphoplasmacellullar bronchitis with adenomatous hyperplasia and squamous epithelium metaplasia because of chronic retention of foreign body. Conclusion: Bronchoscopy examination should be considered in cases where there is an unresolved chronic cough with recurrent pneumonia or persistent actinomycosis in patients with high risk. Cryoprobe is a safe and feasible approach for treatment of airway obstructions due to chronic foreign body retention. Furthermore, relevant findings are discussed here, along with a review of the pathologic alterations and treatment modalities seen in chronic retention of foreign body and airway injury.
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Idiopathic pulmonary fibrosis (IPF) is a chronic human disease with persistent destruction of lung parenchyma. Transforming growth factor-ß1 (TGF-ß1) signaling plays a pivotal role in the initiation and pathogenesis of IPF. As shown herein, TGF-ß1 signaling down-regulated not only peroxisome biogenesis but also the metabolism of these organelles in human IPF fibroblasts. In vitro cell culture observations in human fibroblasts and human lung tissue indicated that peroxisomal biogenesis and metabolic proteins were significantly down-regulated in the lung of 1-month-old transgenic mice expressing a constitutively active TGF-ß type I receptor kinase (ALK5). The peroxisome biogenesis protein peroxisomal membrane protein Pex13p (PEX13p) as well as the peroxisomal lipid metabolic enzyme peroxisomal acyl-coenzyme A oxidase 1 (ACOX1) and antioxidative enzyme catalase were highly up-regulated in TGF-ß type II receptor and Smad3 knockout mice. This study reports a novel mechanism of peroxisome biogenesis and metabolic regulation via TGF-ß1-Smad signaling: interaction of the Smad3 transcription factor with the PEX13 gene in chromatin immunoprecipitation-on-chip assay as well as in a bleomycin-induced pulmonary fibrosis model applied to TGF-ß type II receptor knockout mice. Taken together, data from this study suggest that TGF-ß1 participates in regulation of peroxisomal biogenesis and metabolism via Smad-dependent signaling, opening up novel strategies for the development of therapeutic approaches to inhibit progression of pulmonary fibrosis patients with IPF.
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Fibrosis Pulmonar Idiopática , Factor de Crecimiento Transformador beta1 , Ratones , Animales , Humanos , Lactante , Factor de Crecimiento Transformador beta1/metabolismo , Ratones Transgénicos , Receptor Tipo II de Factor de Crecimiento Transformador beta/genética , Receptor Tipo II de Factor de Crecimiento Transformador beta/metabolismo , Fibrosis Pulmonar Idiopática/inducido químicamente , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/metabolismo , Pulmón/patología , Bleomicina/efectos adversos , Fibroblastos/metabolismo , Ratones NoqueadosRESUMEN
Despite the important functions of PPARγ in various cell types of the lung, PPARγ-deficiency in club cells induces only mild emphysema. Peroxisomes are distributed in a similar way as PPARγ in the lung and are mainly enriched in club and AECII cells. To date, the effects of PPARγ-deficiency on the overall peroxisomal compartment and its metabolic alterations in pulmonary club cells are unknown. Therefore, we characterized wild-type and club cell-specific PPARγ knockout-mice lungs and used C22 cells to investigate the peroxisomal compartment and its metabolic roles in the distal airway epithelium by means of 1) double-immunofluorescence labelling for peroxisomal proteins, 2) laser-assisted microdissection of the bronchiolar epithelium and subsequent qRT-PCR, 3) siRNA-transfection of PPARγand PPRE dual-luciferase reporter activity in C22 cells, 4) PPARg inhibition by GW9662, 5) GC-MS based lipid analysis. Our results reveal elevated levels of fatty acids, increased expression of PPARα and PPRE activity, a strong overall upregulation of the peroxisomal compartment and its associated gene expression (biogenesis, α-oxidation, ß-oxidation, and plasmalogens) in PPARγ-deficient club cells. Interestingly, catalase was significantly increased and mistargeted into the cytoplasm, suggestive for oxidative stress by the PPARγ-deficiency in club cells. Taken together, PPARα-mediated metabolic induction and proliferation of peroxisomes via a PPRE-dependent mechanism could compensate PPARγ-deficiency in club cells.
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Bronquios/metabolismo , Regulación de la Expresión Génica , PPAR alfa/biosíntesis , PPAR gamma/deficiencia , Peroxisomas/metabolismo , Enfisema Pulmonar/metabolismo , Anilidas/farmacología , Animales , Bronquios/patología , Ratones , Ratones Noqueados , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/genética , PPAR alfa/antagonistas & inhibidores , PPAR alfa/genética , Peroxisomas/genética , Enfisema Pulmonar/genética , Enfisema Pulmonar/patologíaRESUMEN
Club (Clara) cells are nonciliated secretory epithelial cells present in bronchioles of distal pulmonary airways. So far, no information is available on the postnatal differentiation of club cells by a combination of molecular biological, biochemical, and stereological approaches in the murine lung. Therefore, the present study was designed to investigate the changes in the club cell secretory proteins (CC10, surfactant proteins A, B and D) and club cell abundance within the epithelium of bronchioles of distal airways during the postnatal development of the mouse lung. Perfusion-fixed murine lungs of three developmental stages (newborn, 15-day-old and adult) were used. Frozen, unfixed lungs were used for cryosectioning and subsequent laser-assisted microdissection of bronchiolar epithelial cells and RT-PCR analyses. High resolution analyses of the three-dimensional structures and composition of lung airways were obtained by scanning electron microscopy. Finally, using design-based stereology, the total and average club cell volume and the volume of secretory granules were quantified by light and transmission electron microscopy. Our results reveal that murine club cells are immature at birth and differentiate postnatally. Further, increase of the club cell volume and number of intracellular granules are closely correlated to the total lung volume enlargement. However, secretory granule density was only increased within the first 15 days of postnatal development. The differentiation is accompanied by a decrease in glycogen content, and a close positive relationship between CC10 expression and secretory granule abundance. Taken together, our data are consistent with the concept that the morphological and functional differentiation of club cells is a postnatal phenomenon.
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Bronquiolos/citología , Bronquiolos/metabolismo , Animales , Animales Recién Nacidos , Bronquiolos/ultraestructura , Técnica del Anticuerpo Fluorescente , Masculino , Ratones Endogámicos C57BL , Adhesión en Parafina , Regulación hacia Arriba , Uteroglobina/metabolismoRESUMEN
In pulmonary research, temperature-sensitive immortalized cell lines derived from the lung of the "immortomouse" (H-2k(b)-tsA58 transgenic mouse), such as C22 club cells and T7 alveolar epithelial cells type II (AECII), are frequently used cell culture models to study CC10 metabolism and surfactant synthesis. Even though peroxisomes are highly abundant in club cells and AECII and might fulfill important metabolic functions therein, these organelles have never been investigated in C22 and T7 cells. Therefore, we have characterized the peroxisomal compartment and its associated gene transcription in these cell lines. Our results show that peroxisomes are highly abundant in C22 and T7 cells, harboring a common set of enzymes, however, exhibiting specific differences in protein composition and gene expression patterns, similar to the ones observed in club cells and AECII in situ in the lung. C22 cells contain a lower number of larger peroxisomes, whereas T7 cells possess more numerous tubular peroxisomes, reflected also by higher levels of PEX11 proteins. Moreover, C22 cells harbor relatively higher amounts of catalase and antioxidative enzymes in distinct subcellular compartments, whereas T7 cells exhibit higher levels of ABCD3 and plasmalogen synthesizing enzymes as well as nuclear receptors of the PPAR family. This study suggest that the C22 and T7 cell lines of the immortomouse lung are useful models to study the regulation and metabolic function of the peroxisomal compartment and its alterations by paracrine factors in club cells and AECII.
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Bronquios/citología , Técnicas de Cultivo de Célula , Células Epiteliales/citología , Modelos Biológicos , Peroxisomas/metabolismo , Alveolos Pulmonares/citología , Alveolos Pulmonares/metabolismo , Animales , Células Cultivadas , Técnica del Anticuerpo Fluorescente , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
Idiopathic pulmonary fibrosis (IPF) is a devastating disease, and its pathogenic mechanisms remain incompletely understood. Peroxisomes are known to be important in ROS and proinflammatory lipid degradation, and their deficiency induces liver fibrosis. However, altered peroxisome functions in IPF pathogenesis have never been investigated. By comparing peroxisome-related protein and gene expression in lung tissue and isolated lung fibroblasts between human control and IPF patients, we found that IPF lungs exhibited a significant down-regulation of peroxisomal biogenesis and metabolism (e.g., PEX13p and acyl-CoA oxidase 1). Moreover, in vivo the bleomycin-induced down-regulation of peroxisomes was abrogated in transforming growth factor beta (TGF-ß) receptor II knockout mice indicating a role for TGF-ß signaling in the regulation of peroxisomes. Furthermore, in vitro treatment of IPF fibroblasts with the profibrotic factors TGF-ß1 or tumor necrosis factor alpha (TNF-α) was found to down-regulate peroxisomes via the AP-1 signaling pathway. Therefore, the molecular mechanisms by which reduced peroxisomal functions contribute to enhanced fibrosis were further studied. Direct down-regulation of PEX13 by RNAi induced the activation of Smad-dependent TGF-ß signaling accompanied by increased ROS production and resulted in the release of cytokines (e.g., IL-6, TGF-ß) and excessive production of collagen I and III. In contrast, treatment of fibroblasts with ciprofibrate or WY14643, PPAR-α activators, led to peroxisome proliferation and reduced the TGF-ß-induced myofibroblast differentiation and collagen protein in IPF cells. Taken together, our findings suggest that compromised peroxisome activity might play an important role in the molecular pathogenesis of IPF and fibrosis progression, possibly by exacerbating pulmonary inflammation and intensifying the fibrotic response in the patients.