Overexpression of matrix metalloproteinases in lung tissue of patients with primary spontaneous pneumothorax

IL11 (Interleukin-11) Causes Emphysematous Lung Disease in a Mouse Model of Marfan Syndrome

BACKGROUND

Marfan Syndrome (MFS) is an inherited connective tissue disorder caused by mutations in the FBN1 (fibrillin-1) gene. Lung abnormalities are common in MFS, but their pathogenesis is poorly understood. IL11 (interleukin-11) causes aortic disease in a mouse model of MFS and was studied here in the lung.

METHODS

We examined histological and molecular phenotypes in the lungs of Fbn1C1041G/+ mice (mouse model of Marfan Syndrome [mMFS]), an established mouse model of MFS. To identify IL11-expressing cells, we used immunohistochemistry on lungs of 4- and 16-week-old Fbn1C1041G/+:Il11EGFP/+ reporter mice. We studied the effects of IL11 inhibition by RT-qPCR, immunoblots and histopathology in lungs from genetic or pharmacologic models: (1) 16-week-old IL11 receptor (IL11RA) knockout mMFS mice (Fbn1C1041G/+:Il11ra1-/- mice) and (2) in mMFS mice administered IgG control or interleukin-11 receptor antibodies twice weekly from 4 to 24 weeks of age.

RESULTS

mMFS lungs showed progressive loss and enlargement of distal airspaces associated with increased proinflammatory and profibrotic gene expression as well as matrix metalloproteinases 2, 9, and 12. IL11 was increased in mMFS lungs and localized to smooth muscle and endothelial cells in young mMFS mice in the Fbn1C1041G/+:Il11EGFP/+ reporter strain and in fibroblasts, in older mice. In mMFS mice, genetic (Fbn1C1041G/+:Il11ra1-/-) or pharmacologic (anti-interleukin-11 receptor) inhibition of IL11 signaling reduced lung emphysema, fibrosis, and inflammation. This protective effect was associated with reduced pathogenic ERK1/2 signaling and lower metalloproteinase 2, 9, and 12 expression.

CONCLUSIONS

IL11 causes lung disease in mMFS. This reveals a shared IL11-driven disease mechanism in lung and aorta in MFS and suggests inhibition of IL11 signaling as a holistic approach for treating multiorgan morbidity in MFS.

The miRNA-24, miRNA-21 expressions and matrix metalloproteinase-7 level in exhaled breath condensate of children with primary spontaneous pneumothorax

Bullous lung diseases may cause primary spontaneous pneumothorax (PSP) in children. The microRNAs (miRNAs) are non-coding RNAs that participate in regulation of inflammation and cancer. We hypothesized that children with bullous lung disease and PSP may have altered miRNA expressions in their exhaled breath condensates (EBCs). Therefore, a prospective study was performed to evaluate the miRNA-24 and 21 expression, and the matrix metalloproteinase-7 (MMP-7) levels in EBC of children with PSP. Children with PSP were evaluated for age, gender, clinical features and results of surgical treatment. EBC samples (500-1000 ml) were collected to evaluate the miRNA-21, 24 expressions, and MMP-7, and tissue-inhibitor-MMP-1 (TIMP-1) levels. miRNA expressions and MMP levels of patients were compared with healthy controls (control group (CG),n= 12). Subjects (n= 16) with a mean age of 15 years (10-19 years), and a male-to-female ratio of 14:2 were enrolled in this study. The most common presenting symptom was sudden chest pain (n= 14). In 62.5% of the cases an underlying bullous lung disease were detected. During an average of 16.6 months (1-60 months) follow up period, four subjects relapsed. The mean MMP-7 (1.74-1.57 ng ml^-1), and TIMP-1 (1.92-1.84 ng ml^-1) levels were similar between both groups (p> 0.05). miRNA-24 expression was significantly decreased in the PSP group, when compared to the CG (0.16-1 2^-ΔΔCT,p< 0.05). In addition, the miRNA-21 expression was not different between the two groups (p> 0.05). In conclusion, the miRNA-24 levels were significantly decreased in children with PSP. Taken together, children with PSP, especially those with bullous disease, should be closely monitored in the long-term period.

Aetiology of Primary Spontaneous Pneumothorax

Air in the pleural cavity is termed pneumothorax. When this occurs in the absence of trauma or medical intervention, it is called spontaneous pneumothorax. Primary spontaneous pneumothorax typically occurs in young patients without known lung disease. However, the idea that these patients have “normal” lungs is outdated. This article will review evidence of inflammation and respiratory bronchiolitis on surgical specimens, discuss the identification of emphysema-like change (i.e., blebs and bullae), the concept of pleural porosity and review recent data on the overexpression of matrix metalloproteinases in the lungs of patients who have had pneumothorax.

Pneumothorax: Classification and Etiology

Pneumothorax is a common problem worldwide. Pneumothorax develops secondary to diverse aetiologies; in many cases, there may be no recognizable lung abnormality. The pathogenetic mechanism(s) causing spontaneous pneumothorax may be related to an interplay between lung-related abnormalities and environmental factors such as smoking. Tobacco smoking is a major risk factor for primary spontaneous pneumothorax; chronic obstructive pulmonary disease is most frequently associated with secondary spontaneous pneumothorax. This review article provides an overview of the historical perspective, epidemiology, classification, and aetiology of pneumothorax. It also aims to highlight current knowledge and understanding of underlying risks and pathophysiological mechanisms in pneumothorax development.

Overexpression of matrix metalloproteinase-9 in adolescents with primary spontaneous pneumothorax for surgical intervention

OBJECTIVE

To determine gene expression profiles associated with bullae formation in patients with primary spontaneous pneumothorax and to identify candidate genes associated with surgical intervention.

METHODS

Twenty-four adolescents with primary spontaneous pneumothorax were enrolled prospectively. A global gene expression analysis of 9 paired lung biopsies (lesion and normal adjacent sites) was performed to identify differentially expressed genes associated with spontaneous pneumothorax. Pathway and network analysis was performed using the Database for Annotation, Visualization and Integrated Discovery web tool. Candidate genes and encoding proteins were assessed in blood samples and compared between patients with pneumothorax and healthy control patients.

RESULTS

A total of 1519 differentially expressed transcripts corresponding to known genes were identified comparing the lesion lung with paired adjacent normal lung. The altered genes were mainly associated with focal adhesion and extracellular matrix-receptor interaction pathways. Genes involved in proteolysis and peptidase activity were up-regulated predominantly, especially matrix metalloproteinase-1 and -9 genes. Compared with the recovery stage, blood levels of matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 were increased at the acute stage in patients with pneumothorax and, when compared between patients treated operatively with those treated nonoperatively, were also significantly greater. In addition, ratios of their serum levels were significantly greater in patients with pneumothorax compared with healthy control patients. Furthermore, matrix metalloproteinase-9 was predominantly overexpressed in neutrophils, alveolar macrophages, and mesothelial cells of lung biopsies.

CONCLUSIONS

An imbalance of cell-extracellular matrix interactions appears to be associated with primary spontaneous pneumothorax. Matrix metalloproteinase-9 overexpression may particularly play a role in contributing to pleural porosity for surgical intervention.

Identification of genes associated with matrix metalloproteinases in invasive lung adenocarcinoma

The aim of the present study was to identify genes with similar function to that of matrix metalloproteinases (MMPs) in invasive lung adenocarcinoma (AC) and to screen the transcription factors that regulate MMPs. The gene expression dataset GSE2514, including 20 invasive lung AC samples and 19 adjacent normal lung samples, was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened using the limma package in R. Genes with similar function to MMPs were identified by K-means clustering. Their correlations with MMPs were validated using Pearson correlation analysis. The expression of MMPs in lung cancer and normal tissues was evaluated by western blot analysis. Protein-protein interaction (PPI) network and transcriptional regulatory network analyses were performed with Retrieval of Interacting Genes and Database for Annotation, Visualization and Integrated Discovery, respectively. As a result, 269 DEGs were identified between invasive lung AC samples and normal lung samples, including 78 upregulated and 191 downregulated genes. Four MMPs (MMP1, MMP7, MMP9 and MMP12), which were upregulated in lung AC, were clustered into one group with other genes, including NAD(P)H quinone oxidoreductase 1, claudin 3 (CLDN3), S100 calcium-binding protein P, serine protease inhibitor Kazal type 1, collagen type XI α 1 chain, periostin and desmoplakin (DSP), following cluster analysis. Pearson correlation analysis further confirmed correlations between MMP9-CLDN3, MMP9-DSP and MMP12-DSP. PPI network analysis also indicated multiple interactions between MMPs-associated genes. Furthermore, MMPs were commonly regulated by CCAAT/enhancer binding protein α transcription factor. These findings may provide further insight into the mechanisms of MMPs in invasive lung AC.

Association of MMP-2 and MMP-9 expression with recurrences in primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) is a common benign problem. However, PSP recurrence is still a troublesome complication for most patients. This study intended to determine the role of matrix metalloproteinase-2 (MMP-2) and MMP-9 in type II pneumocytes of patients with PSP and its relation with recurrence. Ninety-one patients who had undergone needlescopic video-assisted thoracoscopic surgery wedge resection of lung with identifiable blebs for PSP were included in this study. Immunohistochemical (IHC) staining was used to measure the expression of MMP-2 and MMP-9 in lung tissues of PSP patients. The results were further correlated with clinicopathological parameters and recurrence rates using chi-square or Fisher's exact test. The value of MMP-2 and MMP-9 for overall recurrence was analyzed by univariate and multivariable Cox regression model. IHC data revealed that MMP-2 and MMP-9 staining was predominantly observed in type II pneumocytes of patients with PSP. We found that MMP-2 and MMP-9 expression in PSP, especially male PSP patients, was significantly correlated with recurrence. In the univariate and multivariate analyses, MMP-2 and MMP-9 were statistically significant risk factors for overall recurrence in PSP patients. Therefore, high expression levels of MMP-2 and MMP-9 in type II pneumocytes show a positive correlation with PSP recurrence risk. Further studies are needed to validate whether reduction of MMP-2 and MMP-9 expression may be a promising way for decreasing the risk of PSP recurrence in the future.

Correlation of matrix metalloproteinase-2 and -9 expression with recurrences in primary spontaneous pneumothorax patients

BACKGROUND

Primary spontaneous pneumothorax (PSP) is a common benign disorder. However, unpredictable recurrence is a major concern for most patients. The aim of the present study was to assess the role of matrix metalloproteinase-2 (MMP-2) and MMP-9 in alveolar macrophages of patients with PSP and its relationship with recurrence.

METHODS

Ninety-two patients who received needlescopic video-assisted thoracoscopic surgery (NVATS) wedge resection of lung with identifiable blebs for PSP were enrolled for the study. Immunohistochemistry was performed to evaluate the expression of MMP-2 and MMP-9 in lung tissues of patients with PSP. The result was correlated with clinicopathological variables and recurrence rates by the chi-square test. The value of MMP-2 and MMP-9 for overall recurrence was evaluated by univariate and multivariable Cox regression analyses.

RESULTS

The MMP-2 and MMP-9 staining was predominantly observed in alveolar macrophages of patients with PSP. We found that MMP-2 (recurrence: P<0.001; smoking status: P=0.029) and MMP-9 (recurrence: P=0.001; smoking status: P=0.045) expression in PSP, especially male patients, was significantly correlated with recurrence and smoking status. In the multivariate analyses, MMP-2 [hazard ratio (HR) =2.83; 95% confidence interval (CI): 1.37-5.85, P=0.005) and MMP-9 (HR =2.25; 95% CI: 1.19-4.24, P=0.013) were statistically significant risk factors for overall recurrence in PSP patients.

CONCLUSIONS

High expression levels of MMP-2 and MMP-9 showed a positive correlation with recurrence in PSP patients. Further studies are required to test whether inhibition of MMP-2 and MMP-9 expression renders a promising approach for reducing the risk of PSP recurrence in the future.

Abnormal bone mineral density and bone turnover marker expression profiles in patients with primary spontaneous pneumothorax

BACKGROUND

To examine the bone mineral density (BMD) and the role of bone biomarkers, including bone formation marker procollagen type I aminoterminal propeptide (PINP) and N-terminal midmolecule fragment osteocalcin (N-MID), bone resorption marker b-C-telopeptides of type I collagen (b-CTX) and tartrate-resistant acid phosphatase 5b (TRACP5b) in the pathogenesis of PSP.

METHODS

Eighty-three consecutive primary spontaneous pneumothorax (PSP) patients (PSP group) and 87 healthy individuals (control group) were enrolled in this study. General data, including gender, age, height, weight, and body mass index (BMI), were recorded. Dual-energy X-ray absorptiometry, electrochemiluminescence immunoassay (ECLIA), and ELISA were used to evaluate bone mineral density and expression levels of bone metabolism markers, including PINP, b-CTX, TRACP5b, N-MID, and 25-hydroxyvitamin D (25-OH VD).

RESULTS

Mean height was significantly greater in the PSP group compared with the control group, whereas weight and BMI were lower. Patients in the PSP group had significantly lower average bone mineral density, which mainly manifested as osteopenia (11/12, 91.7%); however, only one patient (8.3%) developed osteoporosis. Serum overexpression of PINP, b-CTX, TRACP5b, and N-MID were found in PSP patients. Expression of 25-OH VD was low in PSP patients. Bone resorption markers showed positive linear relationships with bone formation markers in all participants; whereas only TRACP5b expression negatively correlated with 25-OH VD. Expression levels of all bone turnover markers negatively correlated with BMI. Regression analysis identified risk factors of PSP as age, height, weight, and TRACP5b and 25-OH VD expression levels; whereas gender and PINP, b-CTX, and N-MID expression levels were not significantly associated with the onset of PSP.

CONCLUSIONS

It had lower bone mineral density in PSP patients. Bone formation marker PINP, N-MID and bone resorption marker b-CTX, TRACP5b were upregulated in PSP patients. 25-OH VD expression was relatively low in this population of PSP patients. Age, height, weight, and expression levels of TRACP5b and 25-OH VD may be risk factors for PSP.