Increased risk of fibrosing alveolitis associated with interleukin-1 receptor antagonist and tumor necrosis factor-alpha gene polymorphisms

Tetrahedral DNA loaded siCCR2 restrains M1 macrophage polarization to ameliorate pulmonary fibrosis in chemoradiation-induced murine model

Idiopathic pulmonary fibrosis (IPF) is a chronic lethal disease in the absence of demonstrated efficacy for preventing progression. Although macrophage-mediated alveolitis is determined to participate in myofibrotic transition during disease development, the paradigm of continuous macrophage polarization is still under-explored due to lack of proper animal models. Here, by integrating 2.5 U/kg intratracheal Bleomycin administration and 10 Gy thorax irradiation at day 7, we generated a murine model with continuous alveolitis-mediated fibrosis, which mimics most of the clinical features of our involved IPF patients. In combination with data from scRNA-seq of patients and a murine IPF model, a decisive role of CCL2/CCR2 axis in driving M1 macrophage polarization was revealed, and M1 macrophage was further confirmed to boost alveolitis in leading myofibroblast activation. Multiple sticky-end tetrahedral framework nucleic acids conjunct with quadruple ccr2-siRNA (FNA-siCCR2) was synthesized in targeting M1 macrophages. FNA-siCCR2 successfully blocked macrophage accumulation in pulmonary parenchyma of the IPF murine model, thus preventing myofibroblast activation and leading to the disease remitting. Overall, our studies lay the groundwork to develop a novel IPF murine model, reveal M1 macrophages as potential therapeutic targets, and establish new treatment strategy by using FNA-siCCR2, which are highly relevant to clinical scenarios and translational research in the field of IPF.

The Plastic Interplay between Lung Regeneration Phenomena and Fibrotic Evolution: Current Challenges and Novel Therapeutic Perspectives

Interstitial lung diseases (ILDs) are a heterogeneous group of pulmonary disorders characterized by variable degrees of inflammation, interstitial thickening, and fibrosis leading to distortion of the pulmonary architecture and gas exchange impairment. Among them, idiopathic pulmonary fibrosis (IPF) displays the worst prognosis. The only therapeutic options consist of the two antifibrotic drugs, pirfenidone and nintedanib, which limit fibrosis progression but do not reverse the lung damage. The shift of the pathogenetic paradigm from inflammatory disease to epithelium-derived disease has definitively established the primary role of type II alveolar cells, which lose their epithelial phenotype and acquire a mesenchymal phenotype with production of collagen and extracellular matrix (EMC) deposition. Some predisposing environmental and genetic factors (e.g., smoke, pollution, gastroesophageal reflux, variants of telomere and surfactant genes) leading to accelerated senescence set a pro-fibrogentic microenvironment and contribute to the loss of regenerative properties of type II epithelial cells in response to pathogenic noxae. This review provides a complete overview of the different pathogenetic mechanisms leading to the development of IPF. Then, we summarize the currently approved therapies and the main clinical trials ongoing. Finally, we explore the potentialities offered by agents not only interfering with the processes of fibrosis but also restoring the physiological properties of alveolar regeneration, with a particular focus on potentialities and concerns about cell therapies based on mesenchymal stem cells (MSCs), whose anti-inflammatory and immunomodulant properties have been exploited in other fibrotic diseases, such as graft versus host disease (GVHD) and COVID-19-related ARDS.

Distinct TNF-alpha and HLA polymorphisms associate with fibrotic and non-fibrotic subtypes of hypersensitivity pneumonitis

INTRODUCTION

Since Hypersensitivity Pneumonitis (HP) categorization in fibrotic and nonfibrotic/inflammatory types seems to be more consistent with the distinctive clinical course and outcomes, recent international guidelines recommended the use of this classification. Moreover, fibrotic subtype may share immunogenetic and pathophysiological mechanisms with other fibrotic lung diseases.

AIM

To investigate HLA -A, -B, -DRB1 and TNF-α -308 gene polymorphisms among fibrotic and nonfibrotic HP patients due to avian exposure, also in comparison with asymptomatic exposed controls.

METHODS

We prospectively enrolled 40 HP patients, classified as fibrotic or nonfibrotic/inflammatory, and 70 exposed controls. HLA and TNF-α polymorphisms were determined by polymerase chain reaction-sequence specific primer amplification.

RESULTS

While HLA alleles were not associated to HP susceptibility, fibrotic HP patients showed increased frequencies of HLA A*02 (46.7% vs 25.7%; OR=2.53, p = 0.02) and HLA DRB1*14 (10.0% vs 0.7%; OR=15.44, p=0.02) alleles when compared with exposed controls, although not statistically significant after correction for multiple comparisons. TNF-α G/G genotype (associated with low TNF-α production) frequencies were significantly increased among the non-fibrotic/inflammatory HP patients comparatively to fibrotic presentations (88% vs 60%; RR=0.44; p=0.04) and controls (88% vs 63%, OR 4.33, p=0.037). Also, these patients had a significantly increased frequency of the G allele (94.0% vs 73.3%, RR=0.44, p=0.01), while fibrotic HP patients predominantly presented the A allele (26.7% vs 6.0%, RR=2.28, p=0.01).

CONCLUSIONS

Our results support the hypothesis that fibrotic and non-fibrotic HP subtypes exhibit a distinct profile of TNF-α and HLA polymorphisms, which may be relevant to predict disease course and better define treatment strategies.

Precision medicine advances in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a highly heterogeneous, unpredictable and ultimately lethal chronic lung disease. Over the last decade, two anti-fibrotic agents have been shown to slow disease progression, however, both drugs are administered uniformly with minimal consideration of disease severity and inter-individual molecular, genetic, and genomic differences. Advances in biological understanding of disease endotyping and the emergence of precision medicine have shown that "a one-size-fits-all approach" to the management of chronic lung diseases is no longer appropriate. While precision medicine approaches have revolutionized the management of other diseases such as lung cancer and asthma, the implementation of precision medicine in IPF clinical practice remains an unmet need despite several reports demonstrating a large number of diagnostic, prognostic and theragnostic biomarker candidates in IPF. This review article aims to summarize our current knowledge of precision medicine in IPF and highlight barriers to translate these research findings into clinical practice.

A novel quantification method of lung fibrosis based on Micro-CT images developed with the optimized pulmonary fibrosis mice model induced by bleomycin

Background and aims

Idiopathic pulmonary fibrosis (IPF) is a fibrosing lung disease with unknown etiology, leading to cough and dyspnoea, which is also one of the most common sequelae affecting the quality of life of COVID-19 survivors. There is no cure for IPF patients. We aim to develop a reliable IPF animal model with quantification of fibrosis based on Micro-Computer Tomography (micro-CT) images for the new drug discovery, because different bleomycin administration routes, doses, and intervals are reported in the literature, and there is no quantitative assessment of pulmonary fibrosis based on micro-CT images in animal studies.

Methods

We compared three dosages (1.25 mg/kg, 2.5 mg/kg, and 5 mg/kg) of intratracheal bleomycin administration and experiment intervals (14 and 21 days) in C57BL/6 mice by investigating survival rates, pulmonary histopathology, micro-CT, peripheral CD4⁺ & CD8⁺ cells, and cytokines. Moreover, a simple and reliable new method was developed for scoring fibrosis in live mice based on Micro-CT images by using Image J software, which transfers the dark sections in pulmonary Micro-CT images to light colors on a black background.

Results

The levels of hydroxyproline, inflammation cytokine, fibrotic pathological changes, and collagen deposition in the lungs of mice were bleomycin dose-dependent and time-dependent as well as the body weight loss. Based on the above results, the mice model at 21 days after being given bleomycin at 1.25 mg/kg has optimal pulmonary fibrosis with a high survival rate and low toxicity. There is a significant decrease in the light area (gray value at 9.86 ± 0.72) in the BLM mice, indicating that a significant decrease in the alveolar air area was observed in BLM injured mice compared to normal groups (###p < 0.001), while the Pirfenidone administration increased the light area (gray value) to 21.71 ± 2.95 which is close to the value observed in the normal mice (gray value at 23.23 ± 1.66), which is consistent with the protein levels of Col1A1, and α-SMA. Notably, the standard deviations for the consecutive six images of each group indicate the precision of this developed quantitation method for the micro-CT image taken at the fifth rib of each mouse.

Conclusion

Provided a quantifying method for Micro-CT images in an optimal and repeatable pulmonary fibrosis mice model for exploring novel therapeutic interventions.

Mesenchymal Stem Cell-Derived Extracellular Vesicles as Idiopathic Pulmonary Fibrosis Microenvironment Targeted Delivery

Idiopathic pulmonary fibrosis (IPF) affects an increasing number of people globally, yet treatment options remain limited. At present, conventional treatments depending on drug therapy do not show an ideal effect in reversing the lung damage or extending the lives of IPF patients. In recent years, more and more attention has focused on extracellular vesicles (EVs) which show extraordinary therapeutic effects in inflammation, fibrosis disease, and tissue damage repair in many kinds of disease therapy. More importantly, EVs can be modified or used as a drug or cytokine delivery tool, targeting injury sites to enhance treatment efficiency. In light of this, the treatment strategy of mesenchymal stem cell-extracellular vesicles (MSC-EVs) targeting the pulmonary microenvironment for IPF provides a new idea for the treatment of IPF. In this review, we summarized the inflammation, immune dysregulation, and extracellular matrix microenvironment (ECM) disorders in the IPF microenvironment in order to reveal the treatment strategy of MSC-EVs targeting the pulmonary microenvironment for IPF.

Research Progress in the Molecular Mechanisms, Therapeutic Targets, and Drug Development of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease. Recent studies have identified the key role of crosstalk between dysregulated epithelial cells, mesenchymal, immune, and endothelial cells in IPF. In addition, genetic mutations and environmental factors (e.g., smoking) have also been associated with the development of IPF. With the recent development of sequencing technology, epigenetics, as an intermediate link between gene expression and environmental impacts, has also been reported to be implicated in pulmonary fibrosis. Although the etiology of IPF is unknown, many novel therapeutic targets and agents have emerged from clinical trials for IPF treatment in the past years, and the successful launch of pirfenidone and nintedanib has demonstrated the promising future of anti-IPF therapy. Therefore, we aimed to gain an in-depth understanding of the underlying molecular mechanisms and pathogenic factors of IPF, which would be helpful for the diagnosis of IPF, the development of anti-fibrotic drugs, and improving the prognosis of patients with IPF. In this study, we summarized the pathogenic mechanism, therapeutic targets and clinical trials from the perspective of multiple cell types, gene mutations, epigenetic and environmental factors.

Targeting Growth Factor and Cytokine Pathways to Treat Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease of unknown origin that usually results in death from secondary respiratory failure within 2–5 years of diagnosis. Recent studies have identified key roles of cytokine and growth factor pathways in the pathogenesis of IPF. Although there have been numerous clinical trials of drugs investigating their efficacy in the treatment of IPF, only Pirfenidone and Nintedanib have been approved by the FDA. However, they have some major limitations, such as insufficient efficacy, undesired side effects and poor pharmacokinetic properties. To give more insights into the discovery of potential targets for the treatment of IPF, this review provides an overview of cytokines, growth factors and their signaling pathways in IPF, which have important implications for fully exploiting the therapeutic potential of targeting cytokine and growth factor pathways. Advances in the field of cytokine and growth factor pathways will help slow disease progression, prolong life, and improve the quality of life for IPF patients in the future.

Development and Validation of a Novel Gene Signature for Predicting the Prognosis of Idiopathic Pulmonary Fibrosis Based on Three Epithelial-Mesenchymal Transition and Immune-Related Genes

Background: Increasing evidence has revealed that epithelial–mesenchymal transition (EMT) and immunity play key roles in idiopathic pulmonary fibrosis (IPF). However, correlation between EMT and immune response and the prognostic significance of EMT in IPF remains unclear.

Methods: Two microarray expression profiling datasets (GSE70866 and GSE28221) were downloaded from the Gene Expression Omnibus (GEO) database. EMT- and immune-related genes were identified by gene set variation analysis (GSVA) and the Estimation of STromal and Immune cells in MAlignant Tumors using Expression data (ESTIMATE) algorithm. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to investigate the functions of these EMT- and immune-related genes. Cox and least absolute shrinkage and selection operator (LASSO) regression analyses were used to screen prognostic genes and establish a gene signature. Gene Set Enrichment Analysis (GSEA) and Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts (CIBERSORT) were used to investigate the function of the EMT- and immune-related signatures and correlation between the EMT- and immune-related signatures and immune cell infiltration. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to investigate the mRNA expression of genes in the EMT- and immune-related signatures.

Results: Functional enrichment analysis suggested that these genes were mainly involved in immune response. Moreover, the EMT- and immune-related signatures were constructed based on three EMT- and immune-related genes (IL1R2, S100A12, and CCL8), and the K–M and ROC curves presented that the signature could affect the prognosis of IPF patients and could predict the 1-, 2-, and 3-year survival well. Furthermore, a nomogram was developed based on the expression of IL1R2, S100A12, and CCL8, and the calibration curve showed that the nomogram could visually and accurately predict the 1-, 2-, 3-year survival of IPF patients. Finally, we further found that immune-related pathways were activated in the high-risk group of patients, and the EMT- and immune-related signatures were associated with NK cells activated, macrophages M0, dendritic cells resting, mast cells resting, and mast cells activated. qRT-PCR suggested that the mRNA expression of IL1R2, S100A12, and CCL8 was upregulated in whole blood of IPF patients compared with normal samples.

Conclusion: IL1R2, S100A12, and CCL8 might play key roles in IPF by regulating immune response and could be used as prognostic biomarkers of IPF.

Advancing the Adverse Outcome Pathway for PPARγ Inactivation Leading to Pulmonary Fibrosis Using Bradford-Hill Consideration and the Comparative Toxicogenomics Database

Pulmonary fibrosis is regulated by transforming growth factor-β (TGF-β) and peroxisome proliferator-activated receptor-gamma (PPARγ). An adverse outcome pathway (AOP) for PPARγ inactivation leading to pulmonary fibrosis has been previously developed. To advance the development of this AOP, the confidence of the overall AOP was assessed using the Bradford-Hill considerations as per the recommendations from the Organisation for Economic Co-operation and Development (OECD) Users' Handbook. Overall, the essentiality of key events (KEs) and the biological plausibility of key event relationships (KERs) were rated high. In contrast, the empirical support of KERs was found to be moderate. To experimentally evaluate the KERs from the molecular initiating event (MIE) and KE1, PPARγ (MIE) and TGF-β (KE1) inhibitors were used to examine the effects of downstream events following inhibition of their upstream events. PPARγ inhibition (MIE) led to TGF-β activation (KE1), upregulation in vimentin expression (KE3), and an increase in the fibronectin level (KE4). Similarly, activated TGF-β (KE1) led to an increase in vimentin (KE3) and fibronectin expression (KE4). In the database analysis using the Comparative Toxicogenomics Database, 31 genes related to each KE were found to be highly correlated with pulmonary fibrosis, and the top 21 potential stressors were suggested. The AOP for pulmonary fibrosis evaluated in this study will be the basis for the screening of inhaled toxic substances in the environment.

Molecular pathways and role of epigenetics in the idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with unknown etiological factors that can progress to other dangerous diseases like lung cancer. Environmental and genetic predisposition are the two major etiological or risk factors involved in the pathology of the IPF. Among the environmental risk factors, smoking is one of the major causes for the development of IPF. Epigenetic pathways like nucleosomes remodeling, DNA methylation, histone modifications and miRNA mediated genes play a crucial role in development of IPF. Mutations in the genes make the epigenetic factors as important drug targets in IPF. Transcriptional changes due to environmental factors are also involved in the progression of IPF. The mutations in human telomerase reverse transcriptase (hTERT) have shown decreased life expectancy in IPF patients. The TERT-gene is highly expressed in chronic smokers and makes the role of epigenetics evident. Drug like nintedanib acts through vascular endothelial growth factor receptors (VEGFR), while drug pirfenidone acts through transforming growth factor (TGF), which is useful in IPF. Gefitinib, a tyrosine kinase inhibitor of EGFR, is useful as an anti-fibrosis agent in preclinical models. Newer drugs such as Celgene-CC90001 and FibroGen-FG-3019 are currently under investigations acts through the modulating epigenetic mechanisms. Thus, the study on epigenetics opens a wide window for the discovery of newer drugs. This study provides an elementary analysis of multiple regulators of epigenetics and their roles associated with the pathology of IPF. Further, this review also includes epigenetic drugs under development in preclinical and clinical stages.

Immune dysregulation as a driver of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) affects hundreds of thousands of people worldwide, reducing their quality of life and leading to death from respiratory failure within years of diagnosis. Treatment options remain limited, with only two FDA-approved drugs available in the United States, neither of which reverse the lung damage caused by the disease or prolong the life of individuals with IPF. The only cure for IPF is lung transplantation. In this review, we discuss recent major advances in our understanding of the role of the immune system in IPF that have revealed immune dysregulation as a critical driver of disease pathophysiology. We also highlight ways in which an improved understanding of the immune system's role in IPF may enable the development of targeted immunomodulatory therapies that successfully halt or potentially even reverse lung fibrosis.

The roles of signaling pathways in SARS-CoV-2 infection; lessons learned from SARS-CoV and MERS-CoV

The number of descriptions of emerging viruses has grown at an unprecedented rate since the beginning of the 21^st century. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is the third highly pathogenic coronavirus that has introduced itself into the human population in the current era, after SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV). Molecular and cellular studies of the pathogenesis of this novel coronavirus are still in the early stages of research; however, based on similarities of SARS-CoV-2 to other coronaviruses, it can be hypothesized that the NF-κB, cytokine regulation, ERK, and TNF-α signaling pathways are the likely causes of inflammation at the onset of COVID-19. Several drugs have been prescribed and used to alleviate the adverse effects of these inflammatory cellular signaling pathways, and these might be beneficial for developing novel therapeutic modalities against COVID-19. In this review, we briefly summarize alterations of cellular signaling pathways that are associated with coronavirus infection, particularly SARS-CoV and MERS-CoV, and tabulate the therapeutic agents that are currently approved for treating other human diseases.

Genomics of Human Fibrotic Diseases: Disordered Wound Healing Response

Fibrotic disease, which is implicated in almost half of all deaths worldwide, is the result of an uncontrolled wound healing response to injury in which tissue is replaced by deposition of excess extracellular matrix, leading to fibrosis and loss of organ function. A plethora of genome-wide association studies, microarrays, exome sequencing studies, DNA methylation arrays, next-generation sequencing, and profiling of noncoding RNAs have been performed in patient-derived fibrotic tissue, with the shared goal of utilizing genomics to identify the transcriptional networks and biological pathways underlying the development of fibrotic diseases. In this review, we discuss fibrosing disorders of the skin, liver, kidney, lung, and heart, systematically (1) characterizing the initial acute injury that drives unresolved inflammation, (2) identifying genomic studies that have defined the pathologic gene changes leading to excess matrix deposition and fibrogenesis, and (3) summarizing therapies targeting pro-fibrotic genes and networks identified in the genomic studies. Ultimately, successful bench-to-bedside translation of observations from genomic studies will result in the development of novel anti-fibrotic therapeutics that improve functional quality of life for patients and decrease mortality from fibrotic diseases.

T. gondii infection induces IL-1R dependent chronic cachexia and perivascular fibrosis in the liver and skeletal muscle

Cachexia is a progressive muscle wasting disease that contributes to death in a wide range of chronic diseases. Currently, the cachexia field lacks animal models that recapitulate the long-term kinetics of clinical disease, which would provide insight into the pathophysiology of chronic cachexia and a tool to test therapeutics for disease reversal. Toxoplasma gondii (T. gondii) is a protozoan parasite that uses conserved mechanisms to infect rodents and human hosts. Infection is lifelong and has been associated with chronic weight loss and muscle atrophy in mice. We have recently shown that T. gondii-induced muscle atrophy meets the clinical definition of cachexia. Here, the longevity of the T. gondii-induced chronic cachexia model revealed that cachectic mice develop perivascular fibrosis in major metabolic organs, including the adipose tissue, skeletal muscle, and liver by 9 weeks post-infection. Development of cachexia, as well as liver and skeletal muscle fibrosis, is dependent on intact signaling through the type I IL-1R receptor. IL-1α is sufficient to activate cultured fibroblasts and primary hepatic stellate cells (myofibroblast precursors in the liver) in vitro, and IL-1α is elevated in the sera and liver of cachectic, suggesting a mechanism by which chronic IL-1R signaling could be leading to cachexia-associated fibrosis.

Citrus alkaline extracts prevent fibroblast senescence to ameliorate pulmonary fibrosis via activation of COX-2

Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal lung disease with a poor prognosis and limited treatment options. The incidence of IPF increases with age, and the mechanisms related to aging such as cellular senescence have been strongly implicated in disease pathology. Therefore, a better understanding of fibroblasts senescence might provide a new therapeutic strategy to prevent and treat pulmonary fibrosis. In this study, we aimed to explore the effects of citrus alkaline extracts (CAE) on the fibroblasts senescence, and elucidate the underlying mechanism to ameliorate pulmonary fibrosis. We demonstrated that CAE mitigated the collagen deposition by the initial early treatment, suggesting a potential preventive effect of CAE on pulmonary fibrosis. The expression of senescence biomarkers P16^INK4a and P21, concomitant with down-regulation of the myofibroblasts marker α-SMA, and the number of senescence-associated β-galactosidase (SA-β-Gal) positive cells were decreased by CAE treatment, indicating a significant inhibitory effect of CAE on fibroblast senescence. Additionally, CAE down-regulated the expression of the senescence-associated secretory phenotype (SASP) in etoposide-induced senescent fibroblasts. Further studies indicated that COX-2 activation was required for CAE to inhibit the lung fibroblast senescence through a P53-dependent pathway. Results showed that the anti-senescence effect of CAE was abrogated when COX-2 was knocked down or inhibited by COX-2 inhibitor NS-398 or indomethacin in lung fibroblasts. Meanwhile, the anti-fibrotic and anti-senescence effect of CAE were abolished due to disruption of COX-2 in vivo. Collectively, our results provided a novel insight into the potential mechanism of CAE to inhibit the fibroblasts activation through preventing cellular senescence.

Tuberculosis and lung damage: from epidemiology to pathophysiology

A past history of pulmonary tuberculosis (TB) is a risk factor for long-term respiratory impairment. Post-TB lung dysfunction often goes unrecognised, despite its relatively high prevalence and its association with reduced quality of life. Importantly, specific host and pathogen factors causing lung impairment remain unclear. Host immune responses probably play a dominant role in lung damage, as excessive inflammation and elevated expression of lung matrix-degrading proteases are common during TB. Variability in host genes that modulate these immune responses may determine the severity of lung impairment, but this hypothesis remains largely untested. In this review, we provide an overview of the epidemiological literature on post-TB lung impairment and link it to data on the pathogenesis of lung injury from the perspective of dysregulated immune responses and immunogenetics.

Host factors driving lung injury in TB likely contribute to variable patterns of pulmonary impairment after TBhttp://ow.ly/a3of30hBsxB

Inflammasome in the Pathogenesis of Pulmonary Diseases

Lung diseases are common and significant causes of illness and death around the world. Inflammasomes have emerged as an important regulator of lung diseases. The important role of IL-1 beta and IL-18 in the inflammatory response of many lung diseases has been elucidated. The cleavage to turn IL-1 beta and IL-18 from their precursors into the active forms is tightly regulated by inflammasomes. In this chapter, we structurally review current evidence of inflammasome-related components in the pathogenesis of acute and chronic lung diseases, focusing on the "inflammasome-caspase-1-IL-1 beta/IL-18" axis.

Pharmacogenetics and interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease (ILD) is comprised of a heterogeneous group of disorders with highly variable natural histories and response to therapies. Pharmacogenetics focuses on the variability in drug response because of the presence of genetic factors that influence drug metabolism or disease activity. In this article, we review relevant drug-specific and disease-specific polymorphisms that may influence therapeutic response, and then highlight a recently identified drug-gene interaction in patients with idiopathic pulmonary fibrosis (IPF).

RECENT FINDINGS

The emergence of high-throughput genomic technology has allowed for identification of gene polymorphisms associated with susceptibility to specific disease states, including IPF and several connective tissue diseases known to cause ILD. IPF risk loci span a diverse group of genes, while most associated with connective tissue disease are critical to immune signaling. A recent pharmacogenetic analysis of patients enrolled in an IPF clinical trial identified a variant within TOLLIP to be associated with differential response to N-acetylcysteine therapy.

SUMMARY

Though few pharmacogenetic investigations have been conducted in patients with ILD to date, ample opportunities for pharmacogenetic exploration exist in this patient population. Such exploration will advance our understanding of specific ILDs and help usher in an era of personalized medicine.

Effect of a feeder layer composed of mouse embryonic and human foreskin fibroblasts on the proliferation of human embryonic stem cells

The aim of the present study was to investigate the effects of feeder layers composed of various ratios of mouse embryonic fibroblasts (MEFs) and human foreskin fibroblasts (hFFs) on the growth of human embryonic stem cells (hESCs). In addition, the secretion levels of basic fibroblast growth factor (bFGF) by the feeder layers was detected. MEFs and hFFs were treated with mitomycin C and seeded onto gelatin-coated plates at a density of 1×10⁸ cells/l. The hFFs and MEFs were combined and plated at the following ratios: 0:1, 1:2, 1:1, 2:1 and 1:0. The secretion of bFGF by the various hFF/MEF ratio feeder layers was detected using an enzyme-linked immunosorbent assay. Subsequently, hESCs were cultured on top of the various feeder layers. The differences in the cellular morphology of the hESCs were observed using microscopy, and the expression levels alkaline phosphatase (AKP) and octamer-binding transcription factor 4 (OCT-4) were detected using immunohistochemical analysis as indicators of differentiation status. The results showed that the hFFs secreted substantial quantities of bFGF, while no bFGF was secreted by the MEFs. The clones of hESC growing on the feeder layer containing MEF or hFF alone were flat. By contrast, hESC clones grown on a mixed feeder layer containing hFFs + MEFs at a ratio of 1:1 exhibited an accumulated growth with a clear edge, as compared with the other ratios. In addition, hESCs growing on the feeder layer were positive for the expression of AKP and OCT-4. In summary, feeder layer hFFs secreted bFGF, while MEFs did not, indicating that bFGF is not the only factor that supports the growth and differentiation of hESCs. The optimal growth of hESCs was achieved using a mixed feeder layer composed of hFFs + MEFs at a ratio of 1:1.

WISP1 mediates IL-6-dependent proliferation in primary human lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease. IPF is characterized by epithelial cell injury and reprogramming, increases in (myo)fibroblasts, and altered deposition of extracellular matrix. The Wnt1-inducible signaling protein 1 (WISP1) is involved in impaired epithelial-mesenchymal crosstalk in pulmonary fibrosis. Here, we aimed to further investigate WISP1 regulation and function in primary human lung fibroblasts (phLFs). We demonstrate that WISP1 is directly upregulated by Transforming growth factor β1 (TGFβ1) and Tumor necrosis factor α (TNFα) in phLFs, using a luciferase-based reporter system. WISP1 mRNA and protein secretion increased in a time- and concentration-dependent manner by TGFβ1 and TNFα in phLFs, as analysed by qPCR and ELISA, respectively. Notably, WISP1 is required for TGFβ1- and TNFα-dependent induction of interleukin 6 (IL-6), a mechanism that is conserved in IPF phLFs. The siRNA-mediated WISP1 knockdown led to a significant IL-6 reduction after TGFβ1 or TNFα stimulation. Furthermore, siRNA-mediated downregulation or antibody-mediated neutralization of WISP1 reduced phLFs proliferation, a process that was in part rescued by IL-6. Taken together, these results strongly indicate that WISP1-induced IL-6 expression contributes to the pro-proliferative effect on fibroblasts, which is likely orchestrated by a variety of profibrotic mediators, including Wnts, TGFβ1 and TNFα.

Polymorphisms in host immune response associated genes and risk of nasopharyngeal carcinoma development in Portugal

BACKGROUND

Host genetic susceptibility markers in immune response associated genes may contribute to identify individuals with high risk of developing viral infection and viral-associated cancers. We aimed to characterize different polymorphisms in immune response associated genes and evaluate its association with nasopharyngeal carcinoma (NPC) development.

METHODS

We have developed a hospital-based case-control study selecting 134 patients with NPC (cases) and 732 healthy individuals (controls) from the Northern Region of Portugal. Eight single nucleotide polymorphisms (SNP) were selected: -56C>T IFNGR1 (rs2234711), +4854G>T IL1A (rs17561), +3954C>T IL1B (rs1143634), +1902A>G IL4RA (rs1801275), -1082G>A IL10 (rs1800896), +2018T>C IL1RN (rs419598), HLA-A locus A>T (rs2530388), HCGA9 locus A>T (rs6457110). All polymorphisms were analysed by real-time methodology using TaqMan(®) SNP Genotyping Assays.

RESULTS

The overall analysis revealed no statistical significant differences between genotypes distributions in all of studied polymorphisms (p>0.05). However, the results for HCGA9 rs6457110 polymorphism showed a tendency for an increased risk of NPC development among TT carriers with an almost of 2-fold increased risk (OR=1.86; 95%CI 1.00-3.65).

CONCLUSIONS

This is the first study to characterize these polymorphisms in NPC patients in Portugal. Our study indicates that HCGA9 rs6457110 polymorphism might represent a risk marker for NPC development in our population and that other SNPs should be further studied in larger populations to clarify the evidences. This data reinforces the need for more studies, especially in NPC low-prevalent populations.

Understanding Idiopathic Interstitial Pneumonia: A Gene-Based Review of Stressed Lungs

Pulmonary fibrosis is the main cause of severe morbidity and mortality in idiopathic interstitial pneumonias (IIP). In the past years, there has been major progress in the discovery of genetic factors that contribute to disease. Genes with highly penetrant mutations or strongly predisposing common risk alleles have been identified in familial and sporadic IIP. This review summarizes genes harbouring causative rare mutations and replicated common predisposing alleles. To date, rare mutations in nine different genes and five risk alleles fulfil this criterion. Mutated genes represent three genes involved in surfactant homeostasis and six genes involved in telomere maintenance. We summarize gene function, gene expressing cells, and pathological consequences of genetic alterations associated with disease. Consequences of the genetic alteration include dysfunctional surfactant processing, ER stress, immune dysregulation, and maintenance of telomere length. Biological evidence shows that these processes point towards a central role for alveolar epithelial type II cell dysfunction. However, tabulation also shows that function and consequence of most common risk alleles are not known. Most importantly, the predisposition of the MUC5B risk allele to disease is not understood. We propose a mechanism whereby MUC5B decreases surface tension lowering capacity of alveolar surfactant at areas with maximal mechanical stress.

Genetics of Interstitial Lung Disease: Vol de Nuit (Night Flight)

Interstitial lung disease (ILD) is a chronic, progressive fibrotic lung disease with a dismal prognosis. ILD of unknown etiology is referred to as idiopathic interstitial pneumonia (IIP), which is sporadic in the majority of cases. ILD is frequently accompanied by rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), and other autoimmune diseases, and is referred to as collagen vascular disease-associated ILD (CVD-ILD). Susceptibility to ILD is influenced by genetic and environmental factors. Recent advances in radiographic imaging techniques such as high-resolution computed tomography (CT) scanning as well as high-throughput genomic analyses have provided insights into the genetics of ILD. These studies have repeatedly revealed an association between IIP (sporadic and familial) and a single nucleotide polymorphism (SNP) in the promoter region of the mucin 5B (MUC5B). HLA-DRB1*11 alleles have been reported to correlate with ILD in European patients with SSc, whereas in Japanese patients with RA, the HLA-DR2 serological group was identified. The aim of this review is to describe the genetic background of sporadic IIP, CVD-ILD, drug-induced-ILD (DI-ILD), pneumoconiosis, and hypersensitivity pneumonitis. The genetics of ILD is still in progress. However, this information will enhance the understanding of the pathogenesis of ILD and aid the identification of novel therapeutic targets for personalized medicine in future.

The genetic basis of idiopathic pulmonary fibrosis

Throughout the past decade, there have been substantial advances in understanding the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recently, several large genome-wide association and linkage studies have identified common genetic variants in more than a dozen loci that appear to contribute to IPF risk. In addition, family-based studies have led to the identification of rare genetic variants in genes related to surfactant function and telomere biology, and mechanistic studies suggest pathophysiological derangements associated with these rare genetic variants are also found in sporadic cases of IPF. Current evidence suggests that rather than existing as distinct syndromes, sporadic and familial cases of IPF (familial interstitial pneumonia) probably reflect a continuum of genetic risk. Rapidly evolving bioinformatic and molecular biology techniques, combined with next-generation sequencing technologies, hold great promise for developing a comprehensive, integrated approach to defining the fundamental molecular mechanisms that underlie IPF pathogenesis.

Genetic susceptibility and pulmonary fibrosis

PURPOSE OF REVIEW

Recent genetic findings have identified new targets of investigation in the field of pulmonary fibrosis and have the potential to change clinical care.

RECENT FINDINGS

These findings implicate alterations in host defense, cell-to-cell adhesion, and aging and senescence in the pathophysiology of pulmonary fibrosis. At least one common genetic variant strongly associated with pulmonary fibrosis appears to have prognostic implications for patients.

SUMMARY

The inherited risk for pulmonary fibrosis is substantial, and recent data suggest that genetic risk for familial and sporadic forms of the disease are similar. Further characterizing this genetic risk will influence clinical practice in terms of categorization, diagnosis, and screening of individuals for this disease.

Epithelium-dependent profibrotic milieu in the pathogenesis of idiopathic pulmonary fibrosis: current status and future directions

BACKGROUND AND AIM

Idiopathic pulmonary fibrosis (IPF) is characterized by hyperplasia of type II alveolar epithelial cells, aggregation of activated (myo)fibroblasts and excessive deposition of extracellular matrix, which will ultimately lead to lung architecture destruction with no proven effective therapies. Despite a significant increase in our understanding on the etiology and pathogenesis of IPF, the real triggers that initiate epithelial cell injury and promote fibrosis evolution are still elusive. We wanted to discuss the evolution of hypothesis on IPF pathogenesis and to suggest some new directions which need to be further elucidated.

METHODS

We have done a literature search in PubMed database by using the term 'idiopathic pulmonary fibrosis' AND (pathogenesis OR inflammation OR wound healing OR apoptosis OR extracellular matrix OR animal model).

RESULTS

Inflammatory hypothesis had been the dominant idea for several decades which suggests that chronic inflammation drives the onset and advance of the fibrotic process. However, it is seriously challenged nowadays because lung tissues from IPF patients exhibit little inflammatory lesions. Also, anti-inflammation therapy failed to exert a beneficial effect to IPF patients. Furthermore, experimental lung fibrosis can be realized independent of inflammation. Today, modern paradigm suggests that IPF is mainly driven by the profibtic milieu formed by epithelial injury/ disability and dysregulated epithelial mesenchymal interaction.

CONCLUSIONS

Epithelium-dependent profibrotic milieu formation and mesenchymal activation is the current view on the pathogenesis of IPF. New evidence from more analogous animal models may emerge and shift our thinking to a new and more faithful concept in the future.

Locally instilled tumor necrosis factor α antisense oligonucleotide contributes to inhibition of TH 2-driven pulmonary fibrosis via induced CD4+ CD25+ Foxp3+ regulatory T cells

BACKGROUND

Anti-tumor necrosis factor α therapeutics has the potential to alleviate pulmonary fibrosis. However, the systemic administration of anti-tumor necrosis factor α agents has brought about contradictory results and frequent adverse effects, such as infections, immunogenicity and malignancies, amongst others. In the present study, we attempted the local administration of tumor necrosis factor α antisense oligonucleotide and evaluated the treatment effects on pulmonary fibrosis in a bleomycin-induced pulmonary fibrosis mouse model.

METHODS

Flow cytometry for regulatory T cells, reverse transcriptase-polymerase chain reaction for crucial gene expression, western blotting for crucial protein products, immunofluorescent analysis for T(H)2 cells and myofibroblasts, as well as histology analysis for pathological examination, were used.

RESULTS

By local administration of tumor necrosis factor α antisense oligonucleotide, we investigated whether tumor necrosis factor α expression in epithelial cells was significantly inhibited and extracellular matrix overexpression was dramatically reduced. These treatment effects were associated with induced regulatory T cells, reduced T(H)2 cells and generally decreased T(H)2-type cytokine expression. Systemic immunosuppression was not triggered by local antisense oligonucleotide administration because the proportion of regulatory T cells in the blood, thymus or spleen was not affected.

CONCLUSIONS

These findings demonstrate that local administration of tumor necrosis factor α antisense oligonucleotide contributes to anti-fibrotic action via a sustained up-regulated level of regulatory T cells, which inhibits T(H)2-biased responses, pro-fibrotic mediator production and extracellular matrix deposition, with no systemic immunosupression associated with systemically induced regulatory T cells.

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.

Cytokine gene polymorphisms and serum cytokine levels in patients with idiopathic pulmonary fibrosis

Background

Studies have demonstrated associations between cytokine gene polymorphisms and the risk of idiopathic pulmonary fibrosis (IPF). We therefore examined polymorphisms in the genes encoding interleukin (IL)-6, IL-10, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and transforming growth factor-beta 1 (TGF-β₁), and compared the serum levels of these cytokines in IPF patients and healthy controls. Furthermore, we examined the association of the studied genotypes and serum cytokine levels with physiological parameters and the extent of parenchymal involvement determined by high-resolution computed tomography (HRCT).

Methods

Sixty patients with IPF and 150 healthy controls were included. Cytokine genotyping was performed using the polymerase chain reaction sequence specific primer (PCR-SSP) method. In a subset of patients and controls, serum cytokine levels were determined by enzyme-linked immunosorbent assay.

Results

There was no difference between IPF patients and controls in the genotype and allele distributions of polymorphisms in TNF-α, IFN-γ, IL-6, IL-10, and TGF-β₁ (all p > 0.05). The TNF-α (−308) GG, IL-6 (−174) GG and CG, and IL-10 (−1082, -819, -592) ACC ATA genotypes were significantly associated with HRCT scores (all p < 0.05). IL-10 (−1082, -819, -592) ACC haplotype was associated with the diffusion capacity of the lung for carbon monoxide, and ATA haplotype was associated with the partial pressure of oxygen (PaO₂) (all p < 0.05). The TGF-β₁ (codons 10 and 25) TC GG, TC GC, CC GG and CC GC genotypes were significantly associated with the PaO₂ and HRCT scores (p < 0.05). The TGF-β₁ (codons 10 and 25) CC GG genotype (5 patients) was significantly associated with higher PaO₂ value and less parenchymal involvement (i.e., a lower total extent score) compared to the other TGF-β₁ genotypes (81.5 ± 11.8 mm Hg vs. 67.4 ± 11.1 mm Hg, p = 0.009 and 5.60 ± 1.3 vs. 8.51 ± 2.9, p = 0.037, respectively). Significant differences were noted between patients (n = 38) and controls (n = 36) in the serum levels of IL-6 and IL-10 (both, p < 0.0001), but not in the levels of TNF-α and TGF-β₁ (both, p > 0.05).

Conclusion

The studied genotypes and alleles do not predispose to the development of IPF but appear to play an important role in disease severity. Our results suggest that the TGF-β₁ (codons 10 and 25) CC GG genotype could be a useful genetic marker for identifying a subset of IPF patients with a favorable prognosis; however, validation in a larger sample is required.

Familial idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease of unknown etiology, with an appearance of usual interstitial pneumonia on lung biopsy. To-date, about a 100 families diagnosed with IPF have been described. Familial IPF is defined as histologically confirmed IPF occurring in two or more members of a family. Familial pulmonary fibrosis is hereditary, most probably as a feature which is autosomal dominant with variable penetration. Since 2002, we have been following two families with IPF, referred to in the present article as A and B. The patients in Family A included brother, sister, and sister's daughter. We examined two closest relatives of the patients in family A who are healthy. The patients in Family B included father and his two children. In Family B, we examined six other closest relatives, all of whom proved healthy. In all cases, IPF diagnosis was confirmed histologically. We examined human leukocyte antigen (HLA) alleles in both families, including antigens Class I (locus A, B, and C) and Class II (locus DR). On the basis of the results obtained it is impossible to determine the relation between major histocompatibility complex (MHC) polymorphisms and the incidence of the disease.

Molecular mechanisms in progressive idiopathic pulmonary fibrosis

There is clear evidence that environmental exposures and genetic predisposition contribute to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Cigarette smoking increases the risk of developing IPF several-fold, as do other exposures such as metal-fume and wood-dust exposure. Occupations that increase the risk of IPF are agricultural work, hairdressing, and stone polishing, supporting the role of environmental exposure in disease pathogenesis. Genetic predisposition to IPF is evident from its familial aggregation and the fact that pulmonary fibrosis develops in several rare genetic disorders. Mutations in surfactant proteins lead to pulmonary fibrosis and are associated with endoplasmic reticulum stress in alveolar type II epithelial cells. Mutations in telomerase have been found in several families with IPF, and shortened telomeres are found in sporadic cases of IPF. A common variant in mucin 5B predisposes to both familial and sporadic IPF and is present in the majority of cases, indicating sporadic IPF occurs in those with genetic predisposition.

HLA-A and HLA-B gene polymorphism and idiopathic pulmonary fibrosis in a Han Chinese population

Idiopathic pulmonary fibrosis (IPF) is a progressive diffuse interstitial lung disease with poor prognosis of unknown etiology that leading ultimately to death. Predisposing factors are thought to have environmental and genetic inputs.

OBJECTIVE

We investigated the relationship between HLA-A, B gene polymorphism and idiopathic pulmonary fibrosis (IPF) in a Han Chinese population.

PATIENTS AND METHODS

The gene frequency of 36 patients with IPF was detected using a PCR-SSP grouping method. These values were compared with those a Bone Marrow Bank (Shanghai, China) of healthy subjects of identical racial origin as the patient group.

RESULTS

The gene frequency of HLA-A*3 (3.5%), HLA-B*14 (1.4%), -B*15 (10.2%), and -B*40 (5.0%)of the IPF group increased significantly (Pc < 0.05) compared with that in the control group HLA-A*3 (1.0%), HLA-B*14 (0.1%) and -B*15 (1.1%) and -B*40 (0.8%). Investigation of the link between the HLA-A and -B gene showed the gene frequency of HLA-A2B15 to be 5.0% as well as -A2B40 (4.3%), -A11B15 (5.0%), -A24B48 (2.8%) and -A30B40 (2.8%), which were significantly higher than those of the control group (Pc < 0.05).

CONCLUSION

These data suggest that the gene frequency of HLA-A*3, HLA-B*14, -B*15, -B*40, and the linked gene frequency of HLA-A2B15, -A2B40, -A11B15, -A24B58, -A30B40 is associated with IPF pathogenesis.

Disease severity in patients infected with Leishmania mexicana relates to IL-1β

Leishmania mexicana can cause both localized (LCL) and diffuse (DCL) cutaneous leishmaniasis, yet little is known about factors regulating disease severity in these patients. We analyzed if the disease was associated with single nucleotide polymorphisms (SNPs) in IL-1β (−511), CXCL8 (−251) and/or the inhibitor IL-1RA (+2018) in 58 Mexican mestizo patients with LCL, 6 with DCL and 123 control cases. Additionally, we analyzed the in vitro production of IL-1β by monocytes, the expression of this cytokine in sera of these patients, as well as the tissue distribution of IL-1β and the number of parasites in lesions of LCL and DCL patients. Our results show a significant difference in the distribution of IL-1β (−511 C/T) genotypes between patients and controls (heterozygous OR), with respect to the reference group CC, which was estimated with a value of 3.23, 95% CI = (1.2, 8.7) and p-value = 0.0167), indicating that IL-1β (−511 C/T) represents a variable influencing the risk to develop the disease in patients infected with Leishmania mexicana. Additionally, an increased in vitro production of IL-1β by monocytes and an increased serum expression of the cytokine correlated with the severity of the disease, since it was significantly higher in DCL patients heavily infected with Leishmania mexicana. The distribution of IL-1β in lesions also varied according to the number of parasites harbored in the tissues: in heavily infected LCL patients and in all DCL patients, the cytokine was scattered diffusely throughout the lesion. In contrast, in LCL patients with lower numbers of parasites in the lesions, IL-1β was confined to the cells. These data suggest that IL-1β possibly is a key player determining the severity of the disease in DCL patients. The analysis of polymorphisms in CXCL8 and IL-1RA showed no differences between patients with different disease severities or between patients and controls.

Leishmania mexicana is an intracellular parasite that causes two polarly opposed diseases: One is a self-limited disease, characterized by ulcerative lesions associated with a low infectious load, as found in patients with localized cutaneous leishmaniasis (LCL). And the other pole is characterized by a progressive disease where abundant parasites spread uncontrollably throughout the skin inside heavily infected phagocytic cells, as occurs in patients with diffuse cutaneous leishmaniasis (DCL). The cause of this severe form of the disease is unknown, although the early encounter between the parasite and the inflammatory response of the host possibly plays a decisive role in the disease outcome. We here show that polymorphism in the gene encoding IL-1β (−511 C/T) represents a variable influencing the risk to develop the disease for patients infected with Leishmania mexicana. In vitro experiments showed that monocytes of DCL patients secreted significantly higher levels of the proinflammatory cytokine IL-1β as compared to LCL patients. DCL patients also had augmented levels of IL-1β in serum, and the cytokine was diffusely distributed throughout lesions, which was correlated with the numbers of parasites in the lesions. We propose that IL-1β possibly plays a key role in establishing the disease severity in patients infected with Leishmania mexicana.

Smoking and idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology with considerable morbidity and mortality. Cigarette smoking is one of the most recognized risk factors for development of IPF. Furthermore, recent work suggests that smoking may have a detrimental effect on survival of patients with IPF. The mechanism by which smoking may contribute to the pathogenesis of IPF is largely unknown. However, accumulating evidence suggests that increased oxidative stress might promote disease progression in IPF patients who are current and former smokers. In this review, potential mechanisms by which cigarette smoking affects IPF, the effects of cigarette smoking on accelerated loss of lung function in patients with IPF, key genetic studies evaluating the potential candidate genes and gene-environment (smoking) interaction, diagnosis, and treatment with emphasis on recently closed and ongoing clinical trials are presented.

IL1RN genetic variations and risk of IPF: a meta-analysis and mRNA expression study

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating lung disease of unknown aetiology. Genetic variations in the IL1RN gene, encoding the interleukin-1 receptor antagonist (IL-1Ra), have been associated with IPF susceptibility. Several studies investigated the variable number tandem repeat (VNTR) or single nucleotide polymorphisms rs408392, rs419598 and rs2637988, with variable results. The aim of this study was to elucidate the influence of polymorphisms in IL1RN on IPF susceptibility and mRNA expression. We performed a meta-analysis of the five case–control studies that investigated an IL1RN polymorphism in IPF in a Caucasian population. In addition, we investigated whether IL1RN mRNA expression was influenced by IL1RN polymorphisms. The VNTR, rs408392 and rs419598 were in tight linkage disequilibrium, with D′ > 0.99. Furthermore, rs2637988 was in linkage disequilibrium with the VNTR (D′ = 0.90). A haploblock of VNTR*2 and the minor alleles of rs408392and rs419598 was constructed. Meta-analysis revealed that this VNTR*2 haploblock is associated with IPF susceptibility both with an allelic model (odds ratio = 1.42, p = 0.002) and a carriership model (odds ratio = 1.60, p = 0.002). IL1RN mRNA expression was significantly influenced by rs2637988, with lower levels found in carriers of the (minor) GG genotype (p < 0.001). From this meta-analysis, we conclude that the VNTR*2 haploblock is associated with susceptibility to IPF. In addition, polymorphisms in IL1RN influence IL-1Ra mRNA expression, suggesting that lower levels of IL-1Ra predispose to developing IPF. Together these findings demonstrate that the cytokine IL-1Ra plays a role in IPF pathogenesis.

Genetic variability in the IL1RN gene and the balance between interleukin (IL)-1 receptor agonist and IL-1β in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rapidly progressive interstitial lung disease of unknown aetiology. Interleukin (IL)-1β plays an important role in inflammation and has been associated with fibrotic remodelling. We investigated the balance between IL-1β and IL-1 receptor antagonist (IL-1Ra) in bronchoalveolar lavage fluid (BALF) and serum as well as the influence of genetic variability in the IL1B and IL1RN gene on disease susceptibility and cytokine levels. In 77 IPF patients and 349 healthy controls, single nucleotide polymorphisms (SNPs) in the IL1RN and IL1B genes were determined. Serum and BALF IL-1Ra and IL-1β levels were measured using a multiplex suspension bead array system and were correlated with genotypes. Both in serum and BALF a significantly decreased IL-1Ra/IL-1β ratio was found in IPF patients compared to healthy controls. In the IL1RN gene, one SNP was associated with both the susceptibility to IPF and reduced IL-1Ra/IL-1β ratios in BALF. Our results show that genetic variability in the IL1RN gene may play a role in the pathogenesis of IPF and that this role may be more important than thought until recently. The imbalance between IL-1Ra and IL-1β might contribute to a proinflammatory and pro-fibrotic environment in their lungs.

Gene polymorphisms and pharmacogenetics in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic, chronic and inflammatory disease of unknown etiology with genetic predisposition. The advent of new biological agents, as well as the more traditional disease-modifying antirheumatic drugs, has resulted in highly efficient therapies for reducing the symptoms and signs of RA; however, not all patients show the same level of response in disease progression to these therapies. These variations suggest that RA patients may have different genetic regulatory mechanisms. The extensive polymorphisms revealed in non-coding gene-regulatory regions in the immune system, as well as genetic variations in drug-metabolizing enzymes, suggest that this type of variation is of functional and evolutionary importance and may provide clues for developing new therapeutic strategies. Pharmacogenetics is a rapidly advancing area of research that holds the promise that therapies will soon be tailored to an individual patient’s genetic profile.

Novel therapeutic approaches for pulmonary fibrosis

Pulmonary fibrosis represents the end stage of a number of heterogeneous conditions and is, to a greater or lesser degree, the hallmark of the interstitial lung diseases. It is characterized by the excessive deposition of extracellular matrix proteins within the pulmonary interstitium leading to the obliteration of functional alveolar units and in many cases, respiratory failure. While a small number of interstitial lung diseases have known aetiologies, most are idiopathic in nature, and of these, idiopathic pulmonary fibrosis is the most common and carries with it an appalling prognosis - median survival from the time of diagnosis is less than 3 years. This reflects the lack of any effective therapy to modify the course of the disease, which in turn is indicative of our incomplete understanding of the pathogenesis of this condition. Current prevailing hypotheses focus on dysregulated epithelial-mesenchymal interactions promoting a cycle of continued epithelial cell injury and fibroblast activation leading to progressive fibrosis. However, it is likely that multiple abnormalities in a myriad of biological pathways affecting inflammation and wound repair - including matrix regulation, epithelial reconstitution, the coagulation cascade, neovascularization and antioxidant pathways - modulate this defective crosstalk and promote fibrogenesis. This review aims to offer a pathogenetic rationale behind current therapies, briefly outlining previous and ongoing clinical trials, but will focus on recent and exciting advancements in our understanding of the pathogenesis of idiopathic pulmonary fibrosis, which may ultimately lead to the development of novel and effective therapeutic interventions for this devastating condition.

An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management

This document is an international evidence-based guideline on the diagnosis and management of idiopathic pulmonary fibrosis, and is a collaborative effort of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association. It represents the current state of knowledge regarding idiopathic pulmonary fibrosis (IPF), and contains sections on definition and epidemiology, risk factors, diagnosis, natural history, staging and prognosis, treatment, and monitoring disease course. For the diagnosis and treatment sections, pragmatic GRADE evidence-based methodology was applied in a question-based format. For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. It is emphasized that clinicians must spend adequate time with patients to discuss patients' values and preferences and decide on the appropriate course of action.

Gastroesophageal reflux and idiopathic pulmonary fibrosis: a review

The histological counterpart of idiopathic pulmonary fibrosis is usual interstitial pneumonia, in which areas of fibrosis of various ages are interspersed with normal lung. This pattern could be explained by repeated episodes of lung injury followed by abnormal wound healing responses. The cause of the initiating alveolar epithelial injury is unknown, but postulated mechanisms include immunological, microbial, or chemical injury, including aspirated gastric refluxate. Reflux is promoted by low basal pressure in the lower oesophageal sphincter and frequent relaxations, potentiated by hiatus hernia or oesophageal dysmotility. In susceptible individuals, repeated microaspiration of gastric refluxate may contribute to the pathogenesis of IPF. Microaspiration of nonacid or gaseous refluxate is poorly detected by current tests for gastroesophageal reflux which were developed for investigating oesophageal symptoms. Further studies using pharyngeal pH probes, high-resolution impedance manometry, and measurement of pepsin in the lung should clarify the impact of reflux and microaspiration in the pathogenesis of IPF.

Fcγ receptor IIIb (CD16b) polymorphisms are associated with susceptibility to idiopathic pulmonary fibrosis

An excess of neutrophils in the alveoli and lung interstitium has been described in idiopathic pulmonary fibrosis (IPF). Engagement of neutrophil Fcγ receptors with IgG complexes may contribute to the pathogenesis of IPF. The neutrophil FcγRIIIb receptor occurs in two codominantly expressed allelic variants, NA1 and NA2, which exhibit different binding affinities for IgG1 and IgG3 subclasses. The aim of this study was to investigate whether FcγRIIIb genotype is associated with IPF susceptibility or disease progression. In a case-control study we compared the distribution of FcγRIIIb NA1/2 polymorphisms in 142 patients with IPF and in 218 controls using allele-specific PCR amplification. Significant skewing in the distribution of FcγRIIIb genotypes was observed between patients with IPF and control subjects. In the IPF cohort, there was higher frequency of the NA1/NA1 genotype (0.19 vs. 0.07), and lower NA2/NA2 frequency (0.31 vs. 0.50; χ(2) = 17.71, df = 2, P < 0.001). The overall frequency of the NA1 allele was increased in IPF patients compared to controls (0.44 vs. 0.29; P < 0.0001, odds ratio [OR] = 1.93, 95% confidence interval [CI] = 1.42-2.64). Heterozygotes and homozygotes of the NA1 allele were at higher risk of developing IPF (OR = 2.19, 95% CI = 1.40-3.41, P = 0.0005), whereas the NA2 allele was protective against IPF (OR = 0.34, 95% CI = 0.17-0.65, P = 0.0014). There was no association of FcγRIIIb genotype with disease progression as assessed by serial lung function measurements. FcγRIIIb NA1/2 polymorphisms are associated with IPF disease susceptibility. These results support a role for immunological mechanisms contributing to IPF pathogenesis.

Tumour necrosis factor-alpha gene polymorphisms in asbestos-induced diseases

BACKGROUND

Tumour necrosis factor (TNF)-alpha influences the pathogenesis of lung fibrosis and carcinogenesis in normal cells. Polymorphisms of this gene have been suggested to be associated with susceptibility to lung diseases.

METHODS

Association studies were performed in German subjects, using control subjects (n = 177), pulmonary fibrosis patients (n = 612) and bronchial carcinoma patients (n = 374).

RESULTS

Compared with a healthy (control) group, a significant result could be obtained for the asbestosis (patient) group (crude odds ratio (OR(crude)) = 1.57; 95% confidence interval (CI) 1.05-2.36; p = 0.03), especially with severe lung asbestosis (OR(crude) = 4.15; 95% CI 1.06-16.16; p = 0.04). A significant association was revealed when comparing asbestosis patients (OR(crude) = 4.08; 95% CI 1.53-10.54; p = 0.004 and OR(adjusted) = 3.89; 95% CI 1.49-10.17; p = 0.006) with asbestos-induced lung cancer patients.

CONCLUSION

The results confirm the hypothesis that TNF-alpha polymorphisms are associated with asbestos-induced fibrotic or malignant lung diseases in Germans.

Association of FcγRIIa R131H polymorphism with idiopathic pulmonary fibrosis severity and progression

Background

A significant genetic component has been described for idiopathic pulmonary fibrosis (IPF). The R131H (rs1801274) polymorphism of the IgG receptor FcγRIIa determines receptor affinity for IgG subclasses and is associated with several chronic inflammatory diseases. We investigated whether this polymorphism is associated with IPF susceptibility or progression.

Methods

In a case-control study, we compared the distribution of FcγRIIa R131H genotypes in 142 patients with IPF and in 218 controls using allele-specific PCR amplification.

Results

No differences in the frequency of FcγRIIa genotypes were evident between IPF patients and control subjects. However, significantly impaired pulmonary function at diagnosis was observed in HH compared to RR homozygotes, with evidence of more severe restriction (reduced forced vital capacity (FVC)) and lower diffusing capacity for carbon monoxide (DL_CO). Similarly, increased frequency of the H131 allele was observed in patients with severe disease (DL_CO < 40% predicted) (0.53 vs. 0.38; p = 0.03). Furthermore, the H131 allele was associated with progressive pulmonary fibrosis as determined by > 10% drop in FVC and/or > 15% fall in DL_CO at 12 months after baseline (0.48 vs. 0.33; p = 0.023).

Conclusions

These findings support an association between the FcγRIIa R131H polymorphism and IPF severity and progression, supporting the involvement of immunological mechanisms in IPF pathogenesis.