Type I collagen formation in rat type II alveolar cells immortalised by viral gene products

Assessment of viral RNA in idiopathic pulmonary fibrosis using RNA-seq

Background

Numerous publications suggest an association between herpes virus infection and idiopathic pulmonary fibrosis (IPF). These reports have employed immunohistochemistry, in situ hybridization and/or PCR, which are susceptible to specificity artifacts.

Methods

We investigated the possible association between IPF and viral RNA expression using next-generation sequencing, which has the potential to provide a high degree of both sensitivity and specificity. We quantified viral RNA expression for 740 viruses in 28 IPF patient lung biopsy samples and 20 controls. Key RNA-seq results were confirmed using Real-time RT-PCR for select viruses (EBV, HCV, herpesvirus saimiri and HERV-K).

Results

We identified sporadic low-level evidence of viral infections in our lung tissue specimens, but did not find a statistical difference for expression of any virus, including EBV, herpesvirus saimiri and HERV-K, between IPF and control lungs.

Conclusions

To the best of our knowledge, this is the first publication that employs RNA-seq to assess whether viral infections are linked to the pathogenesis of IPF. Our results do not address the role of viral infection in acute exacerbations of IPF, however, this analysis patently did not support an association between herpes virus detection and IPF.

Regulation of silicosis formation by lysophosphatidic acid and its receptors

Silicosis is a serious occupational disease characterized by lung fibrosis that is caused by long-term inhalation of silica-containing fine particles. Lysophosphatidic acid (LPA) and LPA1/3 plays a role in lung fibrosis. Until recently, there has been little research investigating the role of LPA and LPA receptors (LPAR) in silica-induced development of pulmonary fibrosis. In this study, we evaluated the hypothesis that LPA and LPA1/3 may play a role in silicosis pathogenesis using rat silicosis models induced by intratracheal instillation of silica, and randomly divided into control, silica, and VPC-12249 groups. LPA serum and bronchoalveolar lavage fluid (BALF) levels were quantified by ELISA. α-smooth muscle actin (α-SMA), type I and III collagen protein expression was quantified by western blotting (WB), and type I and III collagen mRNAs detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Lung hydroxyproline (HYP) levels were detected using alkaline hydrolysis, with hematoxylin and eosin (H&E) and picrosirius red staining used for pathological examination. In vitro experiments showed that LPA stimulated fibroblasts proliferated in a time and dose-dependent manner and promoted expression of α-SMA, and type I and III collagen. Moreover, LPA serum and BALF levels increased in silica-instilled rats. In vivo and in vitro experiments revealed that α-SMA expression and collagen deposition reduced significantly after VPC-12249 treatment, and histopathological results show VPC-12249 alleviates silicosis progression. In conclusion, our findings suggest that LPA promotes the proliferation, transformation, and collagen synthesis of fibroblasts, and that LPA-LPA1/3 are involved in the development of silicosis and may serve as novel therapeutic targets for treatment.

Regulatory effect of caffeic acid phenethyl ester on type I collagen and interferon-gamma in bleomycin-induced pulmonary fibrosis in rat

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown etiology. Recent investigations have demonstrated that the impaired immune response is a common characteristic feature of IPF. Unfortunately, no definitive and effective drug treatment is available that could improve or at least inhibit the progressive course of this fatal disease. That is why one of the main priorities of pulmonary fibrosis investigations is to identify novel and effective molecular targets for preventive and therapeutic interventions. caffeic acid phenethyl ester (CAPE) is one of the most interesting bioactive compounds extracted from bee propolis. It has been shown that CAPE has an antioxidant activity and modulatory impact on immune system. Accordingly, the aim of the present study was to investigate the regulatory effects of CAPE on the levels of type I collagen (COL-1) and Interferon-gamma (IFN-γ) in bleomycin (BLM)-induced pulmonary fibrosis. Immunohistochemistry procedure was employed to assess the effects of CAPE on lung tissue. In this study, male Sprague-Dawley rats were divided into 5 groups (n=8) included 1: Positive control group: bleomycin (BLM). 2: Negative (saline) control group. 3, 4: Treatment groups of 1 and 2: BLM+CAPE (5 and 10 μmol/kg/day, respectively). (5: Sham group: CAPE (10 μmol/kg/day). BLM application resulted in significant changes in the level of studied parameters as compared to the controls. CAPE could decrease type I collagen concentration, modulate IFN-γ level, increase the animals' body weight and decrease the lung index dose-dependently, compared with model group. In conclusion, CAPE may provide a novel therapeutic target for treating pulmonary fibrosis.

Issues to be considered when studying cancer in vitro

Various cancer treatment approaches have shown promising results when tested preclinically. The results of clinical trials, however, are often disappointing. While searching for the reasons responsible for their failures, the relevance of experimental and preclinical models has to be taken into account. Possible factors that should be considered, including cell modifications during in vitro cultivation, lack of both the relevant interactions and the structural context in vitro have been summarized in the present review.

Tissue factor expression and fibrin deposition in the lungs of patients with idiopathic pulmonary fibrosis and systemic sclerosis

Although abnormalities of alveolar fibrin turnover have been reported to play a role in the development of idiopathic pulmonary fibrosis (IPF), the pathophysiological relevance remains unclear. We therefore investigated the localization of tissue factor (TF) and fibrin deposition in patients with IPF using immunohistochemistry and compared the results with those from patients who had interstitial pneumonia associated with systemic sclerosis (IP-SSc) and idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP). Expression of TF-mRNA was also assessed, using in situ hybridization with a digoxigenin-labeled cRNA probe. In patients with IPF, IP-SSc, and idiopathic BOOP, the TF antigen was positively stained in type II pneumocytes and in some alveolar macrophages. The fibrin antigen was stained in the type II pneumocytes and the adjacent area. Tissue factor-mRNA was expressed in the type II pneumocytes and in some alveolar macrophages. Neither TF antigens nor TF-mRNA were detected in the normal lung. These results indicate that type II pneumocytes are a major source of TF, suggesting that TF production in these cells is closely related to fibrin deposition in the lungs of people with these diseases.

Epstein-Barr virus replication within pulmonary epithelial cells in cryptogenic fibrosing alveolitis

BACKGROUND

Cryptogenic fibrosing alveolitis (synonymous with idiopathic pulmonary fibrosis) is a clinically heterogeneous condition in which the precipitating factor is unclear. Both environmental and infective factors have been implicated. An association between Epstein-Barr virus (EBV) and cryptogenic fibrosing alveolitis was suggested over a decade ago by a study based on EBV serology, but the significance of this has been unclear.

METHODS

Lung tissue obtained surgically from patients (n = 20) with cryptogenic fibrosing alveolitis was investigated for evidence of EBV replication and compared with lung tissue from 21 control patients. Fourteen of the 20 patients had received no specific therapy for cryptogenic fibrosing alveolitis at the time of biopsy. Monoclonal antibodies directed against the EBV viral antigens, EBV viral capsid antigen (VCA) and gp 340/220 antigen, which are expressed during the lytic phase of the EBV life cycle, were studied.

RESULTS

Fourteen (70%) of the 20 patients with cryptogenic fibrosing alveolitis were positive for both EBV VCA and gp 340/220 compared with two (9%) of the 21 controls. In the patients with cryptogenic fibrosing alveolitis viral replication was localised to pulmonary epithelial cells using epithelial cell markers, and immunohistochemical analysis confirmed the staining to be within type II alveolar cells.

CONCLUSIONS

This is the first report of in vivo EBV replication within epithelial cells of the lower respiratory tract in an immunocompetent human host. Furthermore, this suggests that EBV may be an immune trigger or contribute to lung injury in cryptogenic fibrosing alveolitis, thus offering a potential new avenue of treatment.