Protective role of overexpressed MUC5AC against fibrosis in MHV-68-induced combined pulmonary fibrosis and emphysema mouse model

Mucins have long been regarded to play a role as a barrier to prevent mucosal infections; however, some studies report that overexpression of mucins induces obstruction and inflammation of airways. We investigated whether the secretion of overexpressed mucin, mucin5ac (MUC5AC), could improve protection against pathogens. To examine the possible roles of mucin hypersecretion in augmenting host defense against disease-promoting muco-obstructive lung disease, a mouse model that overexpressed MUC5AC was generated. We had previously proved that murine gammaherpesvirus-68 (MHV-68) infection could induce emphysema in mice, which later developed into combined pulmonary fibrosis and emphysema (CPFE). We further explored whether increased MUC5AC secretion could provide benefits against MHV-68 induced fibrosis. We initially developed a pcDNA3.1-MUC5AC mouse model. Next, the experimental mice were randomly divided into five groups: normal control, pcDNA3.1 control, pcDNA3.1-MUC5AC, CPFE, and pcDNA3.1- MUC5AC + CPFE. Morphometric analysis of each group was performed by hematoxylin and eosin staining and Masson trichrome staining. MUC5AC levels in lung tissues were analyzed by immunohistochemical staining, real-time polymerase chain reaction, and Western blot analysis. The airway inflammation was determined by differential cell counts of bronchoalveolar lavage fluid (BALF) and measurement of cytokines and chemokines in BALF by enzyme-linked immunosorbent assay. MUC5AC hypersecretion alone was not sufficient to drive goblet cell metaplasia to induce obvious mucus plugging and airway inflammation. However, MUC5AC overexpression served as a protective barrier against MHV-68 virus infection in vivo. Infectivity of MHV-68 was decreased in the pcDNA3.1-MUC5AC + CPFE group compared with that in CPFE group. Meanwhile, a reduction of MHV-68 virus attenuated the expressions of chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-X-C motif) ligand 5 (CXCL5), interleukin-13 (IL-13), and transforming growth factor-β1 (TGF-β1), and weakened airway inflammation and fibrosis in the pcDNA3.1-MUC5AC + CPFE group. Overexpression of MUC5AC appears to exhibit a protective role against MHV-68 infection in mice with emphysema that subsequently developed into CPFE and to further decrease airway inflammation and fibrosis induced by MHV-68 by decreasing the expressions of CCL2, CXCL5, IL-13, and TGF-β1.     

Pathogenesis of idiopathic pulmonary fibrosis and its clinical implications

Idiopathic pulmonary fibrosis (IPF) is the most common and lethal form of idiopathic interstitial pneumonia. The disease is thought to arise following an aberrant reparative response to recurrent alveolar epithelial cell injury leading to progressive loss of function. The median survival time is 3–5 years from diagnosis. Cigarette smoking, exposure to organic and inorganic dust and genetic factors have been shown to increase the risk of disease, although the cause of IPF remains elusive and its pathogenesis incompletely understood. In the last decade, several clinical trials evaluating novel therapies for IPF have been conducted but the results have been mostly disappointing. Conversely, compounds that target anti-fibrotic and growth factor pathways have been proven effective in slowing functional decline and disease progression. These promising results notwithstanding, truly effective therapeutic strategies will likely require combinations of drugs in order to target the multitude of pathways involved in disease pathogenesis.     

特发性肺纤维化患者血硫化氢水平下降

目的探讨特发性肺纤维化(IPF)患者疾病过程中内源性硫化氢(H2S)的变化和意义,及其与IPF疾病严重程度的关系。方法将研究对象分为IPF组和对照组,检测各组血浆H2S含量。对IPF组行动脉血氧分压、红细胞沉降率(ESR)、C反应蛋白(CRP)、乳酸脱氢酶(LDH)、肺功能及高分辨CT(HRCT)检查;测定IPF组患者在症状急性加重和缓解时血浆H2S含量。结果(1)IPF组血浆H2S含量明显低于对照组(P<0.01);(2)IPF组血浆H2S含量在急性加重时明显高于症状缓解时(P<0.01);(3)随影像学病变进展,IPF组患者血浆H2S含量无明显下降。结论内源性H2S可能参与了IPF的疾病过程,可能与疾病的严重程度相关。     

Targeted resequencing reveals genetic risks in patients with sporadic idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a genetic heterogeneous disease with high mortality and poor prognosis. However, a large fraction of genetic cause remains unexplained, especially in sporadic IPF (～80% IPF). By systemically reviewing related literature and potential pathogenic pathways, 92 potentially IPF‐related genes were selected and sequenced in genomic DNAs from 253 sporadic IPF patients and 125 matched health controls using targeted massively parallel next‐generation sequencing. The identified risk variants were confirmed by Sanger sequencing. We identified two pathogenic and 10 loss‐of‐function (LOF) candidate variants, accounting for 4.74% (12 out of 253) of all the IPF cases. In burden tests, rare missense variants in three genes (CSF3R, DSP, and LAMA3) were identified that have a statistically significant relationship with IPF. Four common SNPs (rs3737002, rs2296160, rs1800470, and rs35705950) were observed to be statistically associated with increased risk of IPF. In the cumulative risk model, high risk subjects had 3.47‐fold (95%CI: 2.07–5.81, P = 2.34 × 10^?6) risk of developing IPF compared with low risk subjects. We drafted a comprehensive map of genetic risks (including both rare and common candidate variants) in patients with IPF, which could provide insights to help in understanding mechanisms, providing genetic diagnosis, and predicting risk for IPF.     

Reduced expression of cyclooxygenase (COX) in idiopathic pulmonary fibrosis and sarcoidosis

AIMS: To test the hypothesis that cyclooxygenase (COX)-1 or COX-2 expression is defective in lungs in idiopathic pulmonary fibrosis (IPF) and to characterize the cellular distribution. IPF is a progressive inflammatory lung disorder with an adverse prognosis. Previous work has shown that prostaglandin E2 (PGE2) regulates collagen deposition and fibroblast proliferation and a defect in COX regulation may contribute to the fibrosis that occurs in IPF. METHODS: Immunohistochemistry was utilized to determine COX immunoreactivity in lung sections from 25 IPF, six sarcoidosis and 14 control subjects. RESULTS: COX-1 and COX-2 expression in bronchiolar epithelial cells was significantly lower in IPF and sarcoidosis than in controls. No significant difference was found in COX-2 expression between macrophages in IPF and control sections, but COX-2 was reduced in macrophages in sarcoidosis compared with controls. CONCLUSIONS: These studies confirm COX-2 loss in bronchial epithelial cells but not macrophages in IPF, and show for the first time reduced constitutive COX-1 expression in epithelial cells and macrophages. Similar abnormalities were observed in sarcoidosis.     

A meta-analysis examining the association between the MUC5B rs35705950 T/G polymorphism and susceptibility to idiopathic pulmonary fibrosis

Inflammation Research - To explore whether the mucin (MUC) 5B rs35705950 T/G polymorphism confers susceptibility to idiopathic pulmonary fibrosis (IPF). A meta-analysis was conducted to determine...     

内源性气体信号分子和调节肽在特发性肺纤维化发病中的作用

特发性肺纤维化是一种病因不明的慢性进行性肺疾病,以纤维增殖、肺实质的破坏及细胞外基质的沉积为特征,其发病机制尚不明确。近几年的研究发现内源性气体信号分子(一氧化氮、一氧化碳和硫化氢)及调节肽(血管紧张素II、松弛素和尾加压素等)在调节肺纤维化,参与特发性肺纤维化的发病中发挥重要的作用。     

In vitro production of B cell growth factor and B cell differentiation factor by peripheral blood mononuclear cells and bronchoalveolar lavage T lymphocytes from patients with idiopathic pulmonary fibrosis.

The activation of B lymphocytes and formation of immune complexes have been suggested to play an important role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). To investigate the mechanisms of activation of B lymphocytes, we studied the production of B cell growth factor (BCGF) and B cell differentiation factor (BCDF) in patients with IPF and those with interstitial pneumonia associated with collagen vascular diseases (IP-CVD), in comparison with healthy controls. Culture supernatants of peripheral blood mononuclear cells from patients with IPF induced more IgM and IgA production by B lymphocytes than those from healthy controls, indicating a higher production of BCDF in the patients. Culture supernatants of T lymphocytes obtained from bronchoalveolar lavage fluids (BALF) of patients with IPF induced higher proliferation of B lymphocytes than those from healthy controls, indicating a higher production of BCGF. An increase in production of BCGF and BCDF was not observed in patients with IP-CVD. In the light of these results, it was suggested that there may be an imbalance in T lymphocyte subsets that release lymphokines like BCGF and BCDF in patients with IPF, and that the subsets may differ between blood and BALF. It remains to be elucidated whether the activation of B lymphocytes depending on T lymphocytes determines the development of disease in IPF.     

From bad to worse: when lung cancer complicates idiopathic pulmonary fibrosis

Patients with idiopathic pulmonary fibrosis have a significantly increased risk for the development of lung cancer. The morbidity and mortality of this disease combination are substantial, and, unfortunately, there are currently few data to help guide clinicians in its diagnosis and treatment. In a recent issue of this journal, Hwang et al presented one of the first studies to evaluate lung cancer in patients with idiopathic pulmonary fibrosis at the molecular level. They demonstrate variants in regulators of the cell cycle, which are known to be important in malignant transformation and may also be important in the pathogenesis of idiopathic pulmonary fibrosis. Further understanding of the pathogenic overlap between lung cancer and idiopathic pulmonary fibrosis could help point the direction to specific diagnostic modalities and targeted treatment of both conditions in the future. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

PAI-1基因4G/5G多态性与特发性肺纤维化的相关性研究

目的探讨纤溶酶原激活剂抑制物-1（plasminogen activator inhibitor-1,PAI-1）基因启动子区4G/5G多态性与特发性肺纤维化（IPF）的相关性。方法应用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）分析,检测42例IPF患者和164例正常对照组人群PAI-1基因4G/5G多态性。结果PAI-1基因4G/4G、4G/5G、5G/5G基因型频率分布,IPF组分别为31.0%、50.0%、19.0%,对照组分别为17.1%、54.9%、28.0%;4G和5G等位基因频率,IPF组分别为0.560和0.440,对照组分别为0.445和0.555;4G/4G基因型频率IPF组显著高于对照组（P〈0.05）。与4G/5G和5G/5G基因型比较,携带4G/4G型个体发生IPF的风险增加2.18倍,95%CI：1.02～4.68（P〈0.05）。结论PAI-1基因4G/5G多态性与IPF的发病相关,纯合子4G/4G基因型可能是IPF发病的重要危险因素之一。     

Detection of antivimentin antibody in sera of patients with idiopathic pulmonary fibrosis and non-specific interstitial pneumonia

It has been suggested that the humoral immune system plays a role in the pathogenesis of non-specific interstitial pneumonia (NSIP). Although some circulating autoantibodies to cytoskeletal protein(s) have been suggested, the antimyofibroblast antibody has not been investigated in patients with idiopathic pulmonary fibrosis (IPF) and NSIP. The purpose of this study is to evaluate the existence of antimyofibroblast antibody in the sera of patients with IPF and NSIP. The MRC5 cell line was used as a model of myofibroblast. The anti-MRC5 cell antibody was characterized in a patient with NSIP using Western blotting. Since we found that one of the anti-MRC5 antibodies was an antivimentin antibody, we established an enzyme-linked immunosorbent assay (ELISA) to measure the levels of antivimentin antibody in the sera of patients with IPF (n = 12) and NSIP (n = 23). Initially, two anti-MRC5 cell antibodies were detected in the sera of patients with NSIP, one of which was characterized as the antivimentin antibody by Western blotting. The other was characterized as an antivimentin fragment antibody. We established an ELISA to measure the antivimentin antibody and found significantly higher levels in patients with IPF and NSIP than in normal volunteers. One of the anti-MRC5 cell antibodies in the serum of a patient with NSIP was against vimentin. The serum levels of antivimentin antibody were increased in patients with IPF and NSIP compared with that of normal volunteers. These results suggest that the antivimentin antibody may be involved in the process of lung injury in IPF and NSIP.     

Genomic profiles of lung cancer associated with idiopathic pulmonary fibrosis

Little is known about the pathogenesis or molecular profiles of idiopathic pulmonary fibrosis‐associated lung cancer (IPF‐LC). This study was performed to investigate the genomic profiles of IPF‐LC and to explore the possibility of defining potential therapeutic targets in IPF‐LC. We assessed genomic profiles of IPF‐LC by using targeted exome sequencing (OncoPanel version 2) in 35 matched tumour/normal pairs surgically resected between 2004 and 2014. Germline and somatic variant calling was performed with GATK HaplotypeCaller and MuTect with GATK SomaticIndelocator, respectively. Copy number analysis was conducted with CNVkit, with focal events determined by Genomic Identification of Significant Targets in Cancer 2.0, and pathway analysis (KEGG) with DAVID. Germline mutations in TERT (rs2736100, n = 33) and CDKN1A (rs2395655, n = 27) associated with idiopathic pulmonary fibrosis risk were detected in most samples. A total of 410 somatic mutations were identified, with an average of 11.7 per tumour, including 69 synonymous, 177 missense, 17 nonsense, 1 nonstop and 11 splice‐site mutations, and 135 small coding indels. Spectra of the somatic mutations revealed predominant C > T transitions despite an extensive smoking history in most patients, suggesting a potential association between APOBEC‐related mutagenesis and the development of IPF‐LC. TP53 (22/35, 62.9%) and BRAF (6/35, 17.1%) were found to be significantly mutated in IPF‐LC. Recurrent focal amplifications in three chromosomal loci (3q26.33, 7q31.2, and 12q14.3) and 9p21.3 deletion were identified, and genes associated with the JAK–STAT signalling pathway were significantly amplified in IPF‐LC (P = 0.012). This study demonstrates that IPF‐LC is genetically characterized by the presence of somatic mutations reflecting a variety of environmental exposures on the background of specific germline mutations, and is associated with potentially targetable alterations such as BRAF mutations. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.