Idiopathic Pulmonary Fibrosis (IPF): An Overview

Baccatin III ameliorates bleomycin-induced pulmonary fibrosis via suppression of TGF-β1 production and TGF-β1-induced fibroblast differentiation

Idiopathic pulmonary fibrosis (IPF) is a progressive and generally lethal lung disease with a high mortality rate. Current therapeutic drugs exhibit limited efficacy but severe adverse effects. Paclitaxel has been identified to exert both anti-inflammatory and anti-fibrosis activity. Baccatin III (BAC), an important precursor of paclitaxel, has been identified as exhibiting immunomodulatory activity with decisively lower toxicity. However, its effects on pulmonary fibrosis remain unknown. In this study, the role of BAC in bleomycin (BLM)-induced pulmonary fibrosis and inflammation in mice was investigated in addition to elucidation of its mechanism of action. Our results demonstrated that administration of BAC in a dose-dependent manner reduced inflammatory infiltration, secretion of the pro-fibrotic mediator TGF-β1 and deposition of collagen and other components of the extracellular matrix (ECM), including alpha smooth muscle actin (α-SMA) and fibronectin. Administration of BAC to treat isolated macrophages stimulated with IL-13, known to activate macrophages, the principal source of TGF-β1, resulted in markedly reduced TGF-β1 expression from macrophages. The AKT/STAT6 signaling pathway was shown to be involved in this process. In addition, we have provided in vitro evidence that BAC inhibits TGF-β1-induced fibroblast differentiation via the Smad2/3 signaling pathway. Furthermore, intratracheal injection of rTGF-β1 significantly exacerbated the degree of fibrosis which was down-regulated by treatment with BAC. Taken together, our data suggest that BAC exerts a protective effect against lung fibrosis and may serve as a potential therapeutic strategy for IPF.

Peptide PD29 treats bleomycin-induced pulmonary fibrosis by inhibiting the TGF-β/smad signaling pathway

Pulmonary fibrosis (PF) is an end-stage change in lung disease characterized by fibroblast proliferation, massive extracellular matrix (ECM) aggregation with inflammatory damage, and severe structural deterioration. PD29 is a 29-amino acid peptide which has the potential to alleviate PF pathogenesis via three mechanisms: anti-angiogenesis, inhibition of matrix metalloproteinase activities, and inhibition of integrins. In this study, fibrotic lung injuries were induced in SD rats by a single intratracheal instillation of 5 mg/kg bleomycin (BLM). Then, these rats were administered 7.5, 5, or 2.5 mg/kg PD29 daily for 30 days. BLM induced-syndromes including structure distortion, excessive deposition of ECM, excessive inflammatory infiltration, and pro-inflammatory cytokine release were used to evaluate the protective effect of PD-29. Oxidative stress damage in lung tissues was attenuated by PD29 in a dose-dependent manner. The expression of TGF-β1 and the phosphorylation of Smad-2/-3-its downstream targets-were enhanced by BLM and weakened by PD29. In vitro, PD29 inhibited TGF-β1-induced epithelial-mesenchymal transition (EMT) and transformation in A549 cells and mouse primary fibroblasts into myofibroblasts. In summary, PD29 reversed EMT and transformation of fibroblasts into myofibroblasts in vitro and prevented PF in vivo possibly by suppressing the TGF-β1/Smad pathway.

Single versus bilateral lung transplantation for idiopathic pulmonary fibrosis

BACKGROUND

Lung transplantation, either single or bilateral, serves as the only effective treatment for end-stage idiopathic pulmonary fibrosis (IPF), but their superiority is still being debated, and its application in Chinese patients has not been data analysed.

METHODS

We reviewed 109 IPF patients who received lung transplantation at our centre between January 1, 2015 and December 31, 2017. The patients were divided into single lung transplantation (SLT) group and bilateral lung transplantation (BLT) group. We compared the two groups' demographic characteristics and clinical indexes (intraoperative conditions, postoperative complications, follow-ups and life qualities).

RESULTS

Patients in BLT group were significantly younger than those in SLT group (P < 0.001), and had more pretransplant infections (P = 0.007). The total ischemic time (P < 0.001) was shorter and intraoperative blood loss was less (P = 0.001) in SLT group. No significant difference was found in the proportion of patients in using anti-fibrosis drugs, pulmonary artery pressure, extracorporeal membrane oxygenation during the surgery; the length of intensive care unit stay; the incidence of complication; and the overall survival rate between two groups. However, the hierarchical analysis found that patients aged > 60 years showed a better survival in SLT group (P = 0.008). Both groups got normal MOS 36-item Short Form (SF-36) scores, and the scores of BLT were higher than those of SLT. The BLT group had better lung function than SLT group 1 year post-lung transplantation.

CONCLUSIONS

Both SLT and BLT are effective and SLT is more favourable for the patients of > 60 years.

The Effects of Epigallocatechin Gallate (EGCG) on Pulmonary Fibroblasts of Idiopathic Pulmonary Fibrosis (IPF)-A Next-Generation Sequencing and Bioinformatic Approach

Idiopathic pulmonary fibrosis (IPF) is a disabling and lethal chronic progressive pulmonary disease. Epigallocatechin gallate (EGCG) is a polyphenol, which is the major biological component of green tea. The anti-oxidative, anti-inflammatory, and anti-fibrotic effects of EGCG have been shown in some studies, whereas its effects in altering gene expression in pulmonary fibroblasts have not been systematically investigated. This study aimed to explore the effect of EGCG on gene expression profiles in fibroblasts of IPF. The pulmonary fibroblasts from an IPF patient were treated with either EGCG or water, and the expression profiles of mRNAs and microRNAs were determined by next-generation sequencing (NGS) and analyzed with the bioinformatics approach. A total of 61 differentially expressed genes and 56 differentially expressed microRNAs were found in EGCG-treated IPF fibroblasts. Gene ontology analyses revealed that the differentially expressed genes were mainly involved in the biosynthetic and metabolic processes of cholesterol. In addition, five potential altered microRNA-mRNA interactions were found, including hsa-miR-939-5p-PLXNA4, hsa-miR-3918-CTIF, hsa-miR-4768-5p-PDE5A, hsa-miR-1273g-3p-VPS53, and hsa-miR-1972-PCSK9. In summary, differentially expressed genes and microRNAs in response to EGCG treatment in IPF fibroblasts were identified in the current study. Our findings provide a scientific basis to evaluate the potential benefits of EGCG in IPF treatment, and warrant future studies to understand the role of molecular pathways underlying cholesterol homeostasis in the pathogenesis of IPF.

Gene Expression Changes Associated with Nintedanib Treatment in Idiopathic Pulmonary Fibrosis Fibroblasts: A Next-Generation Sequencing and Bioinformatics Study

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal interstitial lung disease. Therapeutic options for IPF remain limited. Nintedanib, a tyrosine kinase inhibitor approved for IPF treatment, is known to inhibit fibroblasts proliferation, migration and transformation to myofibroblasts. However, how nintedanib changes gene regulations in IPF has never been systematically investigated. We conducted a next-generation sequencing and bioinformatics study to evaluate the changes of mRNA and miRNA profiles in IPF fibroblasts treated with 2 µM and 4 µM nintedanib, compared to those without treatment. We identified 157 upregulated and 151 downregulated genes and used STRING and DAVID databases for analysis of protein⁻protein interactions, biological pathways, and molecular functions. We found strong protein⁻protein interactions within these dysregulated genes, mostly involved in the pathways of cell cycle and mitotic cell cycle. We also discovered 13 potential miRNA⁻mRNA interactions associated with nintedanib treatment. After validation using miRDB, TargetScan, and RT-qPCR, we identified 4 downregulated genes (DDX11, E2F1, NPTX1, and PLXNA4) which might be repressed by the upregulated hsa-miR-486-3p. According to the proposed functions of DDX11, E2F1, and PLXNA4 reported in previous studies, these gene expression changes together might contribute to decreased proliferation of fibroblasts and decreased angiogenesis in the microenvironment of IPF. Our findings need further studies to confirm.

Bioinformatic analysis of next‑generation sequencing data to identify dysregulated genes in fibroblasts of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lethal fibrotic lung disease with an increasing global burden. It is hypothesized that fibroblasts have a number of functions that may affect the development and progression of IPF. However, the present understanding of cellular and molecular mechanisms associated with fibroblasts in IPF remains limited. The present study aimed to identify the dysregulated genes in IPF fibroblasts, elucidate their functions and explore potential microRNA (miRNA)-mRNA interactions. mRNA and miRNA expression profiles were obtained from IPF fibroblasts and normal lung fibroblasts using a next-generation sequencing platform, and bioinformatic analyses were performed in a step-wise manner. A total of 42 dysregulated genes (>2 fold-change of expression) were identified, of which 5 were verified in the Gene Expression Omnibus (GEO) database analysis, including the upregulation of neurotrimin (NTM), paired box 8 (PAX8) and mesoderm development LRP chaperone, and the downregulation of ITPR interacting domain containing 2 and Inka box actin regulator 2 (INKA2). Previous data indicated that PAX8 and INKA2 serve roles in cell growth, proliferation and survival. Gene Ontology analysis indicated that the most significant function of these 42 dysregulated genes was associated with the composition and function of the extracellular matrix (ECM). A total of 60 dysregulated miRNAs were also identified, and 1,908 targets were predicted by the miRmap database. The integrated analysis of mRNA and miRNA expression data, combined with GEO verification, finally identified Homo sapiens (hsa)-miR-1254-INKA2 and hsa-miR-766-3p-INKA2 as the potential miRNA-mRNA interactions in IPF fibroblasts. In summary, the results of the present study suggest that dysregulation of PAX8, hsa-miR-1254-INKA2 and hsa-miR-766-3p-INKA2 may promote the proliferation and survival of IPF fibroblasts. In the functional analysis of the dysregulated genes, a marked association between fibroblasts and the ECM was identified. These data improve the current understanding of fibroblasts as key cells in the pathogenesis of IPF. As a screening study using bioinformatics approaches, the results of the present study require additional validation.

The Role of Occupational and Environmental Exposures in the Pathogenesis of Idiopathic Pulmonary Fibrosis: A Narrative Literature Review

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease characterised by a progressive and irreversible decline in lung function, which is associated with poor long-term survival. The pathogenesis of IPF is incompletely understood. An accumulating body of evidence, obtained over the past three decades, suggests that occupational and environmental exposures may play a role in the development of IPF. This narrative literature review aims to summarise current understanding and the areas of ongoing research into the role of occupational and environmental exposures in the pathogenesis of IPF.