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

Lactate facilitated mitochondrial fission-derived ROS to promote pulmonary fibrosis via ERK/DRP-1 signaling

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic interstitial lung diseases, which mainly existed in middle-aged and elderly people. The accumulation of reactive oxygen species (ROS) is a common characteristic of IPF. Previous research also shown that lactate levels can be abnormally elevated in IPF patients. Emerging evidence suggested a relationship between lactate and ROS in IPF which needs further elucidation. In this article, we utilized a mouse model of BLM-induced pulmonary fibrosis to detect alterations in ROS levels and other indicators associated with fibrosis. Lactate could induce mitochondrial fragmentation by modulating expression and activity of DRP1 and ERK. Moreover, Increased ROS promoted P65 translocation into nucleus, leading to expression of lung fibrotic markers. Finally, Ulixertinib, Mdivi-1 and Mito-TEMPO, which were inhibitor activity of ERK, DRP1 and mtROS, respectively, could effectively prevented mitochondrial damage and production of ROS and eventually alleviate pulmonary fibrosis. Taken together, these findings suggested that lactate could promote lung fibrosis by increasing mitochondrial fission-derived ROS via ERK/DRP1 signaling, which may provide novel therapeutic solutions for IPF.

Dysregulated bidirectional epithelial-mesenchymal crosstalk: a core determinant of lung fibrosis progression

Progressive lung fibrosis is characterised by dysregulated extracellular matrix (ECM) homeostasis. Understanding of disease pathogenesis remains limited and has prevented the development of effective treatments. While an abnormal wound healing response is strongly implicated in lung fibrosis initiation, factors that determine why fibrosis progresses rather than regular tissue repair occurs are not fully explained. Within human lung fibrosis there is evidence of altered epithelial and mesenchymal lung populations as well as cells undergoing epithelial-mesenchymal transition (EMT), a dynamic and reversible biological process by which epithelial cells lose their cell polarity and down-regulate cadherin-mediated cell-cell adhesion to gain migratory properties. This review will focus upon the role of EMT and dysregulated epithelial-mesenchymal crosstalk in progressive lung fibrosis.

Strengthening pharmacotherapy research for COVID-19-induced pulmonary fibrosis

The global spread of severe acute respiratory syndrome coronavirus 2 has resulted in a significant number of individuals developing pulmonary fibrosis (PF), an irreversible lung injury. This condition can manifest within a short interval following the onset of pneumonia symptoms, sometimes even within a few days. While lung transplantation is a potentially lifesaving procedure, its limited availability, high costs, intricate surgeries, and risk of immunological rejection present significant drawbacks. The optimal timing of medication administration for coronavirus disease 2019 (COVID-19)-induced PF remains controversial. Despite this, it is crucial to explore pharmacotherapy interventions, involving early and preventative treatment as well as pharmacotherapy options for advanced-stage PF. Additionally, studies have demonstrated disparities in anti-fibrotic treatment based on race and gender factors. Genetic mutations may also impact therapeutic efficacy. Enhancing research efforts on pharmacotherapy interventions, while considering relevant pharmacological factors and optimizing the timing and dosage of medication administration, will lead to enhanced, personalized, and fair treatment for individuals impacted by COVID-19-related PF. These measures are crucial in lessening the burden of the disease on healthcare systems and improving patients' quality of life.

Elucidating shared biomarkers in gastroesophageal reflux disease and idiopathic pulmonary fibrosis: insights into novel therapeutic targets and the role of angelicae sinensis radix

Background: The etiological underpinnings of gastroesophageal reflux disease (GERD) and idiopathic pulmonary fibrosis (IPF) remain elusive, coupled with a scarcity of effective therapeutic interventions for IPF. Angelicae sinensis radix (ASR, also named Danggui) is a Chinese herb with potential anti-fibrotic properties, that holds promise as a therapeutic agent for IPF. Objective: This study seeks to elucidate the causal interplay and potential mechanisms underlying the coexistence of GERD and IPF. Furthermore, it aims to investigate the regulatory effect of ASR on this complex relationship. Methods: A two-sample Mendelian randomization (TSMR) approach was employed to delineate the causal connection between gastroesophageal reflux disease and IPF, with Phennoscanner V2 employed to mitigate confounding factors. Utilizing single nucleotide polymorphism (SNPs) and publicly available microarray data, we analyzed potential targets and mechanisms related to IPF in GERD. Network pharmacology and molecular docking were employed to explore the targets and efficacy of ASR in treating GERD-related IPF. External datasets were subsequently utilized to identify potential diagnostic biomarkers for GERD-related IPF. Results: The IVW analysis demonstrated a positive causal relationship between GERD and IPF (IVW: OR = 1.002, 95%CI: 1.001, 1.003; p < 0.001). Twenty-five shared differentially expressed genes (DEGs) were identified. GO functional analysis revealed enrichment in neural, cellular, and brain development processes, concentrated in chromosomes and plasma membranes, with protein binding and activation involvement. KEGG analysis unveiled enrichment in proteoglycan, ERBB, and neuroactive ligand-receptor interaction pathways in cancer. Protein-protein interaction (PPI) analysis identified seven hub genes. Network pharmacology analysis demonstrated that 104 components of ASR targeted five hub genes (PDE4B, DRD2, ERBB4, ESR1, GRM8), with molecular docking confirming their excellent binding efficiency. GRM8 and ESR1 emerged as potential diagnostic biomarkers for GERD-related IPF (ESR1: AUCGERD = 0.762, AUCIPF = 0.725; GRM8: AUCGERD = 0.717, AUCIPF = 0.908). GRM8 and ESR1 emerged as potential diagnostic biomarkers for GERD-related IPF, validated in external datasets. Conclusion: This study establishes a causal link between GERD and IPF, identifying five key targets and two potential diagnostic biomarkers for GERD-related IPF. ASR exhibits intervention efficacy and favorable binding characteristics, positioning it as a promising candidate for treating GERD-related IPF. The potential regulatory mechanisms may involve cell responses to fibroblast growth factor stimulation and steroidal hormone-mediated signaling pathways.

Modelling bronchial epithelial-fibroblast cross-talk in idiopathic pulmonary fibrosis (IPF) using a human-derived in vitro air liquid interface (ALI) culture

Idiopathic Pulmonary Fibrosis (IPF) is a devastating form of respiratory disease with a life expectancy of 3-4 years. Inflammation, epithelial injury and myofibroblast proliferation have been implicated in disease initiation and, recently, epithelial-fibroblastic crosstalk has been identified as a central driver. However, the ability to interrogate this crosstalk is limited due to the absence of in vitro models that mimic physiological conditions. To investigate IPF dysregulated cross-talk, primary normal human bronchial epithelial (NHBE) cells and primary normal human lung fibroblasts (NHLF) or diseased human lung fibroblasts (DHLF) from IPF patients, were co-cultured in direct contact at the air-liquid interface (ALI). Intercellular crosstalk was assessed by comparing cellular phenotypes of co-cultures to respective monocultures, through optical, biomolecular and electrical methods. A co-culture-dependent decrease in epithelium thickness, basal cell mRNA (P63, KRT5) and an increase in transepithelial electrical resistance (TEER) was observed. This effect was significantly enhanced in DHLF co-cultures and lead to the induction of epithelial to mesenchymal transition (EMT) and increased mRNA expression of TGFβ-2, ZO-1 and DN12. When stimulated with exogenous TGFβ, NHBE and NHLF monocultures showed a significant upregulation of EMT (COL1A1, FN1, VIM, ASMA) and senescence (P21) markers, respectively. In contrast, direct NHLF/NHBE co-culture indicated a protective role of epithelial-fibroblastic cross-talk against TGFβ-induced EMT, fibroblast-to-myofibroblast transition (FMT) and inflammatory cytokine release (IL-6, IL-8, IL-13, IL-1β, TNF-α). DHLF co-cultures showed no significant phenotypic transition upon stimulation, likely due to the constitutively high expression of TGFβ isoforms prior to any exogenous stimulation. The model developed provides an alternative method to generate IPF-related bronchial epithelial phenotypes in vitro, through the direct co-culture of human lung fibroblasts with NHBEs. These findings highlight the importance of fibroblast TGFβ signaling in EMT but that monocultures give rise to differential responses compared to co-cultures, when exposed to this pro-inflammatory stimulus. This holds implications for any translation conclusions drawn from monoculture studies and is an important step in development of more biomimetic models of IPF. In summary, we believe this in vitro system to study fibroblast-epithelial crosstalk, within the context of IPF, provides a platform which will aid in the identification and validation of novel targets.

Prognostic significance of peripheral blood S100A12, S100A8, and S100A9 concentrations in idiopathic pulmonary fibrosis

BACKGROUND

S100A12, S100A8, and S100A9 are inflammatory disease biomarkers whose functional significance in idiopathic pulmonary fibrosis (IPF) remains unclear. We evaluated the significance of S100A12, S100A8, and S100A9 levels in IPF development and prognosis.

METHODS

The dataset was collected from the Gene Expression Omnibus (GEO) database and differentially expressed genes were screened using GEO2R. We conducted a retrospective study of 106 patients with IPF to explore the relationships between different biomarkers and poor outcomes. Pearson's correlation coefficient, Kaplan-Meier, Cox regression, and functional enrichment analyses were used to evaluate relationships between these biomarkers' levels and clinical parameters or prognosis.

RESULTS

Serum levels of S100A12, S100A8, and S100A9 were significantly elevated in patients with IPF. The two most significant co-expression genes of S100A12 were S100A8 and S100A9. Patients with levels of S100A12 (median 231.21 ng/mL), S100A9 (median 57.09 ng/mL) or S100A8 (median 52.20 ng/mL), as well as combined elevated S100A12, S100A9, and S100A8 levels, exhibited shorter progression-free survival and overall survival. Serum S100A12 and S100A8, S100A12 and S100A9, S100A9 and S100A8 concentrations also displayed a strong positive correlation (rs2 = 0.4558, rs2 = 0.4558, rs2 = 0.6373; P < 0.001). S100A12 and S100A8/9 concentrations were independent of FVC%, DLCO%, and other clinical parameters (age, laboratory test data, and smoking habit). Finally, in multivariate analysis, the serum levels of S100A12, S100A8, and S100A9 were significant prognostic factors (hazard ratio 1.002, P = 0.032, hazard ratio 1.039, P = 0.001, and hazard ratio 1.048, P = 0.003).

CONCLUSIONS

S100A12, S100A8, and S100A9 are promising circulating biomarkers that may aid in determining IPF patient prognosis. Multicenter clinical trials are needed to confirm their clinical value.

Screening study on significant Chinese herb for anti-idiopathic pulmonary fibrosis by combining clinical experience prescriptions and molecular dynamics simulation technologies

Various techniques such as data mining, network pharmacology, molecular docking and molecular dynamics simulation were used in this study to screen and validate effective herbal medicines for the treatment of idiopathic pulmonary fibrosis (IPF) and to reveal their mechanisms of action at the molecular level. The use of this approach will provide new tools and ideas for future drug screening, especially for the application of herbal medicines in the treatment of complex diseases. Among them, the five identified core targets, including IL6, TP53, AKT1, VEGFA, and TNF, as well as a series of major active compounds, will be important references for future anti-IPF drug development. This information will accelerate the discovery and development of relevant drugs. Meanwhile, this study further confirmed the potential value of four Chinese herbal medicines, including Gancao, Danshen, Huangqin, and Sanqi, in the treatment of IPF. This will promote more clinical trials and practices to confirm and optimise the application of these herbs. Finally, this study is an important theoretical guide to enhance the advantages of Chinese herbal medicines in the prevention and treatment of major and difficult diseases, as well as to understand and utilise the potential efficacy of Chinese herbal medicines. This will further promote the scientific research and clinical application of herbal medicines and provide more possibilities for future disease treatmentCommunicated by Ramaswamy H. Sarma.

Genome-wide DNA methylation analysis of Astragalus and Danshen on the intervention of myofibroblast activation in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF), a chronic progressive interstitial lung disease of unknown etiology, is characterized by continuous damage to alveolar epithelial cells, abnormal repair of alveolar tissue, and alveolar wall scar formation. Currently, the recommended treatment for IPF in Western medicine is relatively limited. In contrast, traditional Chinese medicine and compound prescriptions show advantages in the diagnosis and treatment of IPF, which can be attributed to their multi-channel and multi-target characteristics and minimal side-effects. The purpose of this study was to further corroborate the effectiveness and significance of the traditional Chinese medications Astragalus and Danshen in IPF treatment.

METHODS

We performed whole-genome methylation analysis on nine rat lung tissue samples to determine the epigenetic variation between IPF and non-fibrotic lungs using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses and quantitative reverse transcription polymerase chain reactions.

RESULTS

We identified differentially methylated regions and 105 associated key functional genes in samples related to IPF and Chinese medicine treatment. Based on the methylation levels and gene expression profiles between the Chinese medicine intervention and pulmonary fibrosis model groups, we speculated that Astragalus and Salvia miltiorrhiza (traditionally known as Danshen) act on the Isl1, forkhead box O3, and Sonic hedgehog genes via regulation at transcriptional and epigenetic levels during IPF.

CONCLUSIONS

These findings provide novel insights into the epigenetic regulation of IPF, indicate the effectiveness of Astragalus and Danshen in treating IPF, and suggest several promising therapeutic targets for preventing and treating IPF.

Pulmonary inflammation and fibroblast immunoregulation: from bench to bedside

In recent years, there has been an explosion of interest in how fibroblasts initiate, sustain, and resolve inflammation across disease states. Fibroblasts contain heterogeneous subsets with diverse functionality. The phenotypes of these populations vary depending on their spatial distribution within the tissue and the immunopathologic cues contributing to disease progression. In addition to their roles in structurally supporting organs and remodeling tissue, fibroblasts mediate critical interactions with diverse immune cells. These interactions have important implications for defining mechanisms of disease and identifying potential therapeutic targets. Fibroblasts in the respiratory tract, in particular, determine the severity and outcome of numerous acute and chronic lung diseases, including asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome, and idiopathic pulmonary fibrosis. Here, we review recent studies defining the spatiotemporal identity of the lung-derived fibroblasts and the mechanisms by which these subsets regulate immune responses to insult exposures and highlight past, current, and future therapeutic targets with relevance to fibroblast biology in the context of acute and chronic human respiratory diseases. This perspective highlights the importance of tissue context in defining fibroblast-immune crosstalk and paves the way for identifying therapeutic approaches to benefit patients with acute and chronic pulmonary disorders.

Searching for Novel Candidate Small Molecules for Ameliorating Idiopathic Pulmonary Fibrosis: a Narrative Review

Idiopathic pulmonary fibrosis (IPF) can be defined as a progressive chronic pulmonary disease showing scarring in the lung parenchyma, thereby resulting in increase in mortality and decrease in the quality of life. The pathophysiologic mechanism of fibrosis in IPF is still unclear. Repetitive microinjuries to alveolar epithelium with genetical predisposition and an abnormal restorative reaction accompanied by excessive deposition of collagens are involved in the pathogenesis. Although the two FDA-approved drugs, pirfenidone and nintedanib, are under use for retarding the decline in lung function of patients suffered from IPF, they are not able to improve the survival rate or quality of life. Therefore, a novel therapeutic agent acting on the major steps of the pathogenesis of disease and/or, at least, managing the clinical symptoms of IPF should be developed for the effective regulation of this incurable disease. In the present review, we tried to find a potential of managing the clinical symptoms of IPF by natural products derived from medicinal plants used for controlling the pulmonary inflammatory diseases in traditional Asian medicine. A multitude of natural products have been reported to exert an antifibrotic effect in vitro and in vivo through acting on the epithelial-mesenchymal transition pathway, transforming growth factor (TGF)-β-induced intracellular signaling, and the deposition of extracellular matrix. However, clinical antifibrotic efficacy of these natural products on IPF have not been elucidated yet. Thus, those effects should be proven by further examinations including the randomized clinical trials, in order to develop the ideal and optimal candidate for the therapeutics of IPF.

Update on metabolomic findings in COPD patients

COPD is a heterogeneous disorder that shows diverse clinical presentations (phenotypes and "treatable traits") and biological mechanisms (endotypes). This heterogeneity implies that to carry out a more personalised clinical management, it is necessary to classify each patient accurately. With this objective, and in addition to clinical features, it would be very useful to have well-defined biological markers. The search for these markers may either be done through more conventional laboratory and hypothesis-driven techniques or relatively blind high-throughput methods, with the omics approaches being suitable for the latter. Metabolomics is the science that studies biological processes through their metabolites, using various techniques such as gas and liquid chromatography, mass spectrometry and nuclear magnetic resonance. The most relevant metabolomics studies carried out in COPD highlight the importance of metabolites involved in pathways directly related to proteins (peptides and amino acids), nucleic acids (nitrogenous bases and nucleosides), and lipids and their derivatives (especially fatty acids, phospholipids, ceramides and eicosanoids). These findings indicate the relevance of inflammatory-immune processes, oxidative stress, increased catabolism and alterations in the energy production. However, some specific findings have also been reported for different COPD phenotypes, demographic characteristics of the patients, disease progression profiles, exacerbations, systemic manifestations and even diverse treatments. Unfortunately, the studies carried out to date have some limitations and shortcomings and there is still a need to define clear metabolomic profiles with clinical utility for the management of COPD and its implicit heterogeneity.

HSP47: A Therapeutic Target in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by a progressive decline in lung function and poor prognosis. The deposition of the extracellular matrix (ECM) by myofibroblasts contributes to the stiffening of lung tissue and impaired oxygen exchange in IPF. Type I collagen is the major ECM component and predominant collagen protein deposited in chronic fibrosis, suggesting that type I collagen could be a target of drugs for fibrosis treatment. Heat shock protein 47 (HSP47), encoded by the serpin peptidase inhibitor clade H, member 1 gene, is a stress-inducible collagen-binding protein. It is an endoplasmic reticulum-resident molecular chaperone essential for the correct folding of procollagen. HSP47 expression is increased in cellular and animal models of pulmonary fibrosis and correlates with pathological manifestations in human interstitial lung diseases. Various factors affect HSP47 expression directly or indirectly in pulmonary fibrosis models. Overall, understanding the relationship between HSP47 expression and pulmonary fibrosis may contribute to the development of novel therapeutic strategies.

Lipid metabolism in idiopathic pulmonary fibrosis: From pathogenesis to therapy

Idiopathic pulmonary fibrosis (IPF) is a chronic irreversible interstitial lung disease characterized by a progressive decline in lung function. The etiology of IPF is unknown, which poses a significant challenge to the treatment of IPF. Recent studies have identified a strong association between lipid metabolism and the development of IPF. Qualitative and quantitative analysis of small molecule metabolites using lipidomics reveals that lipid metabolic reprogramming plays a role in the pathogenesis of IPF. Lipids such as fatty acids, cholesterol, arachidonic acid metabolites, and phospholipids are involved in the onset and progression of IPF by inducing endoplasmic reticulum stress, promoting cell apoptosis, and enhancing the expression of pro-fibrotic biomarkers. Therefore, targeting lipid metabolism can provide a promising therapeutic strategy for pulmonary fibrosis. This review focuses on lipid metabolism in the pathogenesis of pulmonary fibrosis.

Nanoengineered mesenchymal stem cell therapy for pulmonary fibrosis in young and aged mice

Pulmonary fibrosis (PF) is an age-related interstitial lung disease that results in notable morbidity and mortality. The Food and Drug Administration-approved drugs can decelerate the progression of PF; however, curing aged patients with severe fibrosis is ineffective because of insufficient accumulation of these drugs and wide necrocytosis of type II alveolar epithelial cells (AEC IIs). Here, we constructed a mesenchymal stem cell (MSC)-based nanoengineered platform via the bioconjugation of MSCs and type I collagenase-modified liposomes loaded with nintedanib (MSCs-Lip@NCAF) for treating severe fibrosis. Specifically, MSCs-Lip@NCAF migrated to fibrotic lungs because of the homing characteristic of MSCs and then Lip@NCAF was sensitively released. Subsequently, Lip@NCAF ablated collagen fibers, delivered nintedanib into fibroblasts, and inhibited fibroblast overactivation. MSCs differentiated into AEC IIs to repair alveolar structure and ultimately promote the regeneration of damaged lungs in aged mice. Our findings indicated that MSCs-Lip@NCAF could be used as a promising therapeutic candidate for PF therapy, especially in aged patients.

Thoracic pain in patients with chronic interstitial lung disease-an underestimated symptom

Introduction

Prevalence and predisposing factors for the development of thoracic pain (TP) in patients with chronic interstitial lung disease (cILD) are largely unknown. Underestimation and insufficient therapy of pain can lead to worsened ventilatory function. Quantitative sensory testing is an established tool for characterization of chronic pain and its neuropathic components. We investigated frequency and intensity of TP in cILD patients and the potential association with lung function and quality of life.

Materials and methods

We prospectively investigated patients with chronic interstitial lung disease to analyze risk factors for the development of thoracic pain and quantify thoracic pain through quantitative sensory testing. In addition, we studied the relationship between pain sensitivity and lung function impairment.

Results

Seventy-eight patients with chronic interstitial lung disease and 36 healthy controls (HCs) were included. Thoracic pain occurred in 38 of 78 patients (49%), most frequently in 13 of 18 (72%, p = 0.02) patients with pulmonary sarcoidosis. The occurrence was mostly spontaneous and not related to thoracic surgical interventions (76%, p = 0.48). Patients with thoracic pain showed a significant impairment of mental well-being (p = 0.004). A higher sensitivity to pinprick stimulation during QST can be observed in patients with thoracic pain (p < 0.001). Steroid treatment was associated with lower sensitivity within thermal (p = 0.034 and p = 0.032) and pressure pain testing (p = 0.046). We observed a significant correlation between total lung capacity and thermal (p = 0.019 and p = 0.03) or pressure pain sensitivity (p = 0.006 and p = 0.024).

Conclusion

This study was performed to investigate prevalence, risk factors and thoracic pain in patients with chronic interstitial lung disease. Thoracic pain mostly occurs spontaneous as a frequent symptom, and seems to be an underestimated symptom in patients with chronic interstitial lung disease, especially those with pulmonary sarcoidosis. Timely identification of thoracic pain may allow starting symptomatic treatment at early stage, before impairment in quality of life occurs.

Clinical Trial Registration

https://www.drks.de/drks_web/, Deutsches Register Klinischer Studien (DRKS) DRKS00022978.

Advances in cellular senescence in idiopathic pulmonary fibrosis (Review)

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible and fatal interstitial lung disease of unknown cause, with a median survival of 2-3 years. Its pathogenesis is unclear and there is currently no effective treatment for IPF. Approximately two-thirds of patients with IPF are >60 years old, with a mean age of 66 years, suggesting a link between aging and IPF. However, the mechanism by which aging promotes development of PF remains unclear. Senescence of alveolar epithelial cells and lung fibroblasts (LFs) and their senescence-associated secretion phenotype (SASP) may be involved in the occurrence and development of IPF. The present review focus on senescence of LFs and epithelial and stem cells, as well as SASP, the activation of profibrotic signaling pathways and potential treatments for pathogenesis of IPF.

Attenuation of Ventilation-Enhanced Epithelial–Mesenchymal Transition through the Phosphoinositide 3-Kinase-γ in a Murine Bleomycin-Induced Acute Lung Injury Model

Mechanical ventilation (MV) used in patients with acute lung injury (ALI) induces lung inflammation and causes fibroblast proliferation and excessive collagen deposition—a process termed epithelial–mesenchymal transition (EMT). Phosphoinositide 3-kinase-γ (PI3K-γ) is crucial in modulating EMT during the reparative phase of ALI; however, the mechanisms regulating the interactions among MV, EMT, and PI3K-γ remain unclear. We hypothesized that MV with or without bleomycin treatment would increase EMT through the PI3K-γ pathway. C57BL/6 mice, either wild-type or PI3K-γ-deficient, were exposed to 6 or 30 mL/kg MV for 5 h after receiving 5 mg/kg AS605240 intraperitoneally 5 days after bleomycin administration. We found that, after bleomycin exposure in wild-type mice, high-tidal-volume MV induced substantial increases in inflammatory cytokine production, oxidative loads, Masson’s trichrome staining level, positive staining of α-smooth muscle actin, PI3K-γ expression, and bronchial epithelial apoptosis (p < 0.05). Decreased respiratory function, antioxidants, and staining of the epithelial marker Zonula occludens-1 were also observed (p < 0.05). MV-augmented bleomycin-induced pulmonary fibrogenesis and epithelial apoptosis were attenuated in PI3K-γ-deficient mice, and we found pharmacological inhibition of PI3K-γ activity through AS605240 (p < 0.05). Our data suggest that MV augmented EMT after bleomycin-induced ALI, partially through the PI3K-γ pathway. Therapy targeting PI3K-γ may ameliorate MV-associated EMT.

Caveolin-1-Related Intervention for Fibrotic Lung Diseases

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease (ILD) for which there are no effective treatments. Lung transplantation is the only viable option for patients with end-stage PF but is only available to a minority of patients. Lung lesions in ILDs, including IPF, are characterized by alveolar epithelial cell (AEC) senescence and apoptosis and accumulation of activated myofibroblasts and/or fibrotic lung (fL) fibroblasts (fLfs). These composite populations of fLfs show a high rate of basal proliferation, resist apoptosis and senescence, and have increased migration and invasiveness. They also more readily deposit ECM proteins. These features eventuate in progressive destruction of alveolar architecture and loss of lung function in patients with PF. The identification of new, safer, and more effective therapy is therefore mandatory for patients with IPF or related ILDs. We found that increased caveolin-1 and tumor suppressor protein, p53 expression, and apoptosis in AECs occur prior to and then with the proliferation of fLfs in fibrotic lungs. AECs with elevated p53 typically undergo apoptosis. fLfs alternatively demonstrate strikingly low basal levels of caveolin-1 and p53, while mouse double minute 2 homolog (mdm2) levels and mdm2-mediated degradation of p53 protein are markedly increased. The disparities in the expression of p53 in injured AECs and fLfs appear to be due to increased basal expression of caveolin-1 in apoptotic AECs with a relative paucity of caveolin-1 and increased mdm2 in fLfs. Therefore, targeting caveolin-1 using a caveolin 1 scaffolding domain peptide, CSP7, represents a new and promising approach for patients with IPF, perhaps other forms of progressive ILD or even other forms of organ injury characterized by fibrotic repair. The mechanisms of action differ in the injured AECs and in fLfs, in which differential signaling enables the preservation of AEC viability with concurrent limitation of fLf expansion and collagen secretion. The findings in three models of PF indicate that lung scarring can be nearly abrogated by airway delivery of the peptide. Phase 1 clinical trial testing of this approach in healthy volunteers has been successfully completed; Phase 1b in IPF patients is soon to be initiated and, if successful, will be followed by phase 2 testing in short order. Apart from the treatment of IPF, this intervention may be applicable to other forms of tissue injury characterized by fibrotic repair.

MicroRNA let-7d attenuates hypertrophic scar fibrosis through modulation of iron metabolism by reducing DMT1 expression

Hypertrophic scar is an unavoidable result of wound healing following burns and trauma, which remains a challenging problem for clinicians. Previously, we demonstrated that exosomal microRNAs (miRs) of human amniotic epithelial cells accelerated wound healing and inhibited scar formation. However, the underlying mechanism is still unclear. In this particular study, we found that miR-let-7d reduced collagen deposition, and this was accompanied by decreased level of iron content in myofibroblasts. Importantly, inhibition of miR-let-7d in myofibroblasts accelerated collagen deposition and promoted cell proliferation. In addition, bioinformatics prediction combined with classical dual-luciferase reporter gene assay demonstrated that the cellular iron importer divalent metal transporter 1 (DMT1) was a target gene of miR-let-7d, and the miR-let-7d mimics inhibited the expression of DMT1 in myofibroblasts. Moreover, silencing of DMT1 with small interfering RNA (siRNA) reduced the deposition of extracellular matrix. Consistent with the results in vitro, the miR-let-7d mimics effectively ameliorated hypertrophic scar fibrosis in a rabbit ear hypertrophic scar model. Taken together, our results indicated for the first time that miR-let-7d attenuated hypertrophic scar fibrosis through modulation of iron metabolism by reducing iron uptake through DMT1, which may provide a novel therapeutic strategy for hypertrophic scar.

Theophylline Attenuates BLM-Induced Pulmonary Fibrosis by Inhibiting Th17 Differentiation

Idiopathic pulmonary fibrosis (IPF) is a chronic and refractory interstitial lung disease. Although there are two approved drugs for IPF, they were not able to completely cure the disease. Therefore, the development of new drugs is required for the effective treatment of IPF. In this study, we investigated the effect of theophylline, which has long been used for the treatment of asthma, on pulmonary fibrosis. The administration of theophylline attenuated the fibrotic changes of lung tissues and improved mechanical pulmonary functions in bleomycin (BLM)-induced pulmonary fibrosis. Theophylline treatment suppressed IL-17 production through inhibiting cytokines controlling Th17 differentiation; TGF-β, IL-6, IL-1β, and IL-23. The inhibition of IL-6 and IL-1β by theophylline is mediated by suppressing BLM-induced ROS production and NF-κB activation in epithelial cells. We further demonstrated that theophylline inhibited TGF-β-induced epithelial-to-mesenchymal transition in epithelial cells through suppressing the phosphorylation of Smad2/3 and AKT. The inhibitory effects of theophylline on the phosphorylation of Smad2/3 and AKT were recapitulated in BLM-treated lung tissues. Taken together, these results demonstrated that theophylline prevents pulmonary fibrosis by inhibiting Th17 differentiation and TGF-β signaling.

B4GALT1 as a New Biomarker of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease characterized by progressive scarring of the lung that involves the pulmonary interstitium. The disease may rapidly progress, leading to respiratory failure, and the long-term survival is poor. There are no accurate biomarkers available so far. Our aim was to evaluate the expression of the B4GALT1 in patients with IPF. Analysis of B4GALT1 gene expression was performed in silico on two gene sets, retrieved from the Gene Expression Omnibus database. Expression of B4GALT1 was then evaluated, both at the mRNA and protein levels, on lung specimens obtained from lung biopsies of 4 IPF patients, on one IPF-derived human primary cell and on 11 cases of IPF associated with cancer. In silico re-analysis demonstrated that the B4GALT1 gene was overexpressed in patients and human cell cultures with IPF (p = 0.03). Network analysis demonstrated that B4GALT1 upregulation was correlated with genes belonging to the EMT pathway (p = 0.01). The overexpression of B4GALT1 was observed, both at mRNA and protein levels, in lung biopsies of our four IPF patients and in the IPF-derived human primary cell, in other fibrotic non-lung tissues, and in IPF associated with cancer. In conclusion, our results indicate that B4GALT1 is overexpressed in IPF and could represent a novel marker of this disease.

The Role of Serum 1,25-Dihydroxy Vitamin D3 and PCT in Idiopathic Pulmonary Fibrosis

OBJECTIVE

Biomarkers for the acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) are urgently needed to provide better patient management. We aimed to investigate whether serum 1,25(OH)2D3 (1,25-dihydroxy vitamin D3) levels predict AE-IPF and whether they could be a potential prognostic biomarker for IPF.

PARTICIPANTS AND METHODS

This prospective study included 72 patients with IPF (31 with stable IPF and 41 with AE-IPF). All participants were recruited during hospitalisation at Tianjin Chest Hospital and were followed up for at least 12 months. Demographics, comorbidities, arterial blood gas, and serum biochemical profile, radiological features, and anti-fibrotic therapy were evaluated. Serum concentrations of 1,25(OH)2D3 and transforming growth factor beta1 (TGFβ1) were detected using enzyme-linked immunosorbent assay (ELISA). Risk factors for AE-IPF were identified using multivariate analysis. Prognostic factors were assessed using Kaplan-Meier and Cox regression analyses.

RESULTS

Baseline values of alveolar-arterial oxygen difference (A-aDO2) (40.85 mmHg vs 29.2 mmHg, p =0.035), white blood cell counts (10.09 ± 4.2×109/L vs 7.46 ± 7.84×109/L, p <0.001), percentage of monocytes (7.36 ± 1.36% vs 6.6 ± 1.2%, p =0.017), C-reactive protein (CRP) (2.1 mg/dL vs 1.12 mg/dL, p =0.015) and procalcitonin (PCT) (36.59% vs 3.23%, p <0.001) were significantly higher in AE-IPF patients than in stable IPF patients. Instead, the mean concentration of serum calcium and 1,25(OH)2D3 at baseline were higher in IPF patients with stable disease than in those with acute exacerbation (2.17 ± 0.13 nmol/L vs 2.09 ± 0.13 nmol/L, p =0.023 and 16.62 pg/mL vs 11.58 pg/mL, p <0.001, respectively). In multivariate analysis, a higher proportion of patients with lower serum 1,25(OH)2D3 levels experienced AE-IPF (OR 0.884, 95% CI 0.791-0.987, p =0.029), and rising serum PCT level (PCT > 0.05 ng/mL) was associated with an increased risk of mortality (HR 3.664, 95% CI 1.010-12.900, p =0.043).

CONCLUSION

Decreased serum 1,25(OH)2D3 is associated with an increased risk of acute exacerbation for patients with IPF. A high serum PCT level is predictive of worse prognosis in IPF patients. 1,25(OH)2D3 may be a potential biomarker for AE-IPF, while PCT could be a prognostic biomarker for IPF.

Positive Autoantibody Is Associated with Malignancies in Patients with Idiopathic Interstitial Pneumonias

Various autoantibodies are associated with clinical outcomes in patients with idiopathic interstitial pneumonias (IIPs). We retrospectively analyzed the association between autoantibodies and malignancies in IIP patients. Comprehensive analyses of autoantibodies were performed using immunoprecipitation and enzyme-linked immunosorbent assays in 193 consecutive IIP patients. Cancer-related factors were analyzed using logistic regression analysis. In total, 22 of 193 patients (11.4%) with IIP had malignant disease. In univariate analysis, positivity for any autoantibody (odds ratio (OR), 3.1; 95% confidence interval (CI), 1.2-7.7; p = 0.017) and antinuclear antibody titer ≥1:320 (OR, 3.4; CI, 1.2-9.8; p = 0.024) were significantly associated with malignancies. Positive anti-aminoacyl tRNA synthetase (ARS) (OR, 3.7; CI, 0.88-15.5; p = 0.074) and anti-Ro52 antibody (OR, 3.2; CI, 0.93-11.2; p = 0.065) tended to be associated with malignancies. In multivariate analysis, independent risk factors were male sex (OR, 3.7; CI, 1.0-13.5; p = 0.029) and positivity for any autoantibody (OR, 3.9; CI, 1.5-10.1; p = 0.004) in model 1, and male sex (OR, 3.9; CI, 1.0-15.3; p = 0.049), antinuclear antibody titer ≥1:320 (OR, 4.2; CI, 1.4-13.3; p = 0.013), and positivity for anti-ARS antibody (OR, 6.5; CI, 1.2-34.1; p = 0.026) in model 2. Positivity for any autoantibody, antinuclear and anti-ARS antibodies, and male sex were independent risk factors for malignancies in IIP patients. Testing autoantibodies in IIP patients might help the early diagnosis of malignancies.

Insights from DOCK2 in cell function and pathophysiology

Dedicator of cytokinesis 2 (DOCK2) can activate the downstream small G protein Rac and regulate cytoskeletal reorganization. DOCK2 is essential for critical physiological processes such as migration, activation, proliferation, and effects of immune cells, including lymphocytes, neutrophils, macrophages, and dendritic cells. For example, DOCK2 is involved in the development and activation of T and B lymphocytes by affecting synapse formation and inhibiting the development of the Th2 lineage by downregulating IL-4Rα surface expression. Not only that, DOCK2 may be a molecular target for controlling cardiac transplant rejection and Alzheimer’s disease (AD). Patients with defects in the DOCK2 gene also exhibit a variety of impaired cellular functions, such as chemotactic responses of lymphocytes and reactive oxygen species (ROS) production by neutrophils. To date, DOCK2 has been shown to be involved in the development of various diseases, including AD, pneumonia, myocarditis, colitis, tumors, etc. DOCK2 plays different roles in these diseases and the degree of inflammatory response has a different impact on the progression of disease. In this paper, we present a review of recent advances in the function of DOCK2 in various immune cells and its role in various diseases.