Idiopathic pulmonary fibrosis: an update

Formononetin-Loaded PLGA Large Porous Microparticles via Intratracheal Instillation for Bleomycin-Induced Pulmonary Fibrosis Treatment

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease of unknown cause, with few effective therapies available and high mortality rates. Our preceding research indicated that formononetin (FMN) could improve the symptoms of the bleomycin-induced pulmonary fibrosis and be a promising drug against IPF. In this study, an inhalable formononetin-loaded poly(lactic-co-glycolic) acid (PLGA) large porous microspheres (FMN-PLGA-MSs) was prepared by the method of emulsion solvent evaporation. SEM showed that FMN-PLGA-MSs were loose particles existing many pores on the surfaces, and the measured mean geometric diameter was more than 10 µm. The encapsulation efficiency (EE) and drug loading efficiency (DL) were 87.72 ± 6.34% and 4.18 ± 0.30%. FMN in FMN-PLGA-MSs could be rapidly released within 2 h and sustainably released for 21 d. Cell tests and q-RT-PCR tests showed that FMN could inhibit the activation of fibroblasts and the deposition of extracellular matrix (ECM) by acting on the TGF-β1/Smad3 signaling pathway. FMN-PLGA-MSs showed higher antifibrotic effects than free FMN oral administration in the pulmonary fibrosis models of mice, remarkably improving pulmonary function, decreasing hydroxyproline levels, and attenuating lung injuries. By formulating formononetin into microsphere preparations, its solubility can be significantly enhanced, enabling effective pulmonary drug delivery. This approach not only improves lung targeting but also reduces systemic toxicity. Additionally, it facilitates superior lung deposition and extends the retention time of the formononetin within the lungs. Taken together, FMN-PLGA-MSs may be a promising inhaled medication for the treatment of IPF.

Idiopathic Pulmonary Fibrosis Mortality by Industry and Occupation - United States, 2020-2022

Idiopathic pulmonary fibrosis (IPF), a progressive lung disease characterized by scarring and worsening lung function, has a poor prognosis. A recent systematic review estimated that 21% of IPF deaths might be attributable to occupational exposures. To describe IPF mortality among U.S. residents aged ≥15 years who were ever employed, by industry and occupation, CDC conducted an exploratory analysis of 2020-2022 multiple cause-of-death data. During 2020-2022, a total of 67,843 (39,712 [59%] male and 28,131 [41%] female) decedents had IPF, suggesting that during this 3-year period, 8,340 IPF deaths in males and 5,908 deaths in females might have been associated with occupational exposures. By industry group, the highest proportionate mortality ratios among males were among those employed in utilities (1.15) and among females, were among those employed in public administration (1.12). By occupation group, the highest IPF mortality rates among males were among community and social services workers (1.23) and among females among farming, fishing, and forestry workers (1.24). Estimates of elevated IPF mortality among workers in specific industries and occupations warrant confirmation, control of known exposure-related risk factors, and continued surveillance to better understand the full range of occupational exposures that might increase risk for developing IPF.

Nonmalignant respiratory disease mortality among dentists in the United States from 1979 through 2018

BACKGROUND

Dentists can be exposed to dust and nanoparticles from teeth, dental composites, and metal alloys generated during dental procedures, and exposure to dust can cause respiratory diseases, including pulmonary fibrosis. The authors describe mortality from nonmalignant respiratory diseases (NMRDs) among dentists in the United States.

METHODS

The authors submitted information on US dentists who died from 1979 through 2018 to a centralized US death records database to obtain underlying causes of death. Decedent data that met records-matching criteria were analyzed using the Life Table Analysis System software (National Institute for Occupational Safety and Health) to calculate proportionate mortality ratios (PMRs), indirectly standardized for age, sex, race, and 5-year calendar period with 95% CIs, for NMRD and a group of International Classification of Diseases, Ninth and Tenth Revision codes approximating idiopathic pulmonary fibrosis.

RESULTS

Among 21,928 dentist decedents with complete race information, 1,583 deaths (7.2%) resulted from NMRD. Proportionate mortality for dentist decedents was significantly lower than the general population for NMRD overall (PMR, 0.66; 95% CI, 0.62 to 0.69), chronic obstructive pulmonary disease (PMR, 0.44; 95% CI, 0.41 to 0.48), and pneumonia (PMR, 0.73; 95% CI, 0.67 to 0.81) but significantly higher than the general population for the pulmonary fibrosis group (PMR, 1.57; 95% CI, 1.37 to 1.80).

CONCLUSIONS

Dentists had decreased proportionate mortality for most NMRD and increased proportionate mortality for underlying causes of death associated with pulmonary fibrosis.

PRACTICAL IMPLICATIONS

Existing engineering controls that reduce inhalational exposures during dental procedures might be inadequate. Improved characterization of these exposures could help inform more effective engineering controls.

Anti-oxidants as therapeutic agents for oxidative stress associated pathologies: future challenges and opportunities

Free radicals have been implicated in the pathogenesis of cancer along with cardiovascular, neurodegenerative, pulmonary and inflammatory disorders. Further, the relationship between oxidative stress and disease is distinctively established. Clinical trials using anti-oxidants for the prevention of disease progression have indicated some beneficial effects. However, these trials failed to establish anti-oxidants as therapeutic agents due to lack of efficacy. This is attributed to the fact that living systems are under dynamic redox control wherein their redox behavior is compartmentalized and simple aggregation of redox couples, distributed throughout the system, is of miniscule importance while determining their overall redox state. Further, free radical metabolism is intriguingly complex as they play plural roles segregated in a spatio-temporal manner. Depending on quality, quantity and site of generation, free radicals exhibit beneficial or harmful effects. Use of nonspecific, non-targeted, general ROS scavengers lead to systemic elimination of all types of ROS and interferes in cellular signaling. Failure of anti-oxidants to act as therapeutic agents lies in this oversimplification of extremely dynamic cellular redox environment as a static and non-compartmentalized redox state. Rather than generalizing the term "oxidative stress" if we can identify the "type of oxidative stress" in different types of diseases, a targeted and more specific anti-oxidant therapy may be developed. In this review, we discuss the concept of redox dynamics, role and type of oxidative stress in disease conditions, and current status of anti-oxidants as therapeutic agents. Further, we probe the possibility of developing novel, targeted and efficacious anti-oxidants with drug-like properties.

Investigating the Potential of Ufasomes Laden with Nintedanib as an Optimized Targeted Lung Nanoparadigm for Accentuated Tackling of Idiopathic Pulmonary Fibrosis

Background/objectives: Idiopathic pulmonary fibrosis (IPF) is a prevalent interstitial lung disease that typically progresses gradually, leading to respiratory failure and ultimately death. IPF can be treated with the tyrosine kinase inhibitor, nintedanib (NTD), owing to its anti-fibrotic properties, which ameliorate the impairment of lung function. This study aimed to formulate, optimize, and assess NTD-loaded ufasomes (NTD-UFSs) as a nanosystem for its pulmonary targeting to snowball the bioavailability and therapeutic efficacy of the drug. Methods: To investigate the influence of numerous factors on NTD-UFSs assembly and to determine the optimal formulation, Box-Behnken statistical design was implemented with the assistance of Design-Expert® software. The thin-film hydration strategy was employed to fabricate NTD-UFSs. The optimum NTD-UFSs formulation was subsequently selected and subjected to additional evaluations. Also, using a rat model, a comparative pharmacokinetic analysis was scrutinized. Results: The optimal NTD-UFSs elicited an accumulative release of 65.57% after 24 h, an encapsulation efficiency of 62.51%, a zeta potential of -36.07 mV, and a vesicular size of 364.62 nm. In addition, it disclosed remarkable stability and a continuous cumulative release pattern. In vivo histopathological studies ascertained the tolerability of NTD-UFSs administered intratracheally. According to the pharmacokinetic studies, intratracheal NTD-UFSs administration manifested a significantly higher AUC0-∞ value than oral and intratracheal NTD suspensions, by approximately 5.66- and 3.53-fold, respectively. Conclusions: The findings of this study proposed that UFSs might be a promising nanoparadigm for the non-invasive pulmonary delivery of NTD.

STATs, promising targets for the treatment of autoimmune and inflammatory diseases

Cytokines play a crucial role in the pathophysiology of autoimmune and inflammatory diseases, with over 50 cytokines undergoing signal transduction through the Signal Transducers and Activators of Transcription (STAT) signaling pathway. Recent studies have solidly confirmed the pivotal role of STATs in autoimmune and inflammatory diseases. Therefore, this review provides a detailed summary of the immunological functions of STATs, focusing on exploring their mechanisms in various autoimmune and inflammatory diseases. Additionally, with the rapid advancement of structural biology in the field of drug discovery, many STAT inhibitors have been identified using structure-based drug design strategies. In this review, we also examine the structures of STAT proteins and compile the latest research on STAT inhibitors currently being tested in animal models and clinical trials for the treatment of immunological diseases, which emphasizes the feasibility of STATs as promising therapeutic targets and provides insights into the design of the next generation of STAT inhibitors.

Idiopathic pulmonary fibrosis (IPF): disease pathophysiology, targets, and potential therapeutic interventions

Idiopathic pulmonary fibrosis (IPF) is a progressive, degenerative pulmonary condition. Transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), and tumor necrosis factor-α (TNF-α) are the major modulators of IPF that mediate myofibroblast differentiation and promote fibrotic remodeling of the lung. Cigarette smoke, asbestos fiber, drugs, and radiation are known to favor fibrotic remodeling of the lungs. Oxidative stress in the endoplasmic reticulum (ER) also leads to protein misfolding and promotes ER stress, which is predominant in IPF. This phenomenon further results in excess reactive oxygen species (ROS) aggregation, increasing oxidative stress. During protein folding in the ER, thiol groups on the cysteine residue are oxidized and disulfide bonds are formed, which leads to the production of hydrogen peroxide (H2O2) as a by-product. With the accumulation of misfolded proteins in the ER, multiple signaling cascades are initiated by the cell, collectively termed as the unfolded protein response (UPR). UPR also induces ROS production within the ER and mitochondria and promotes both pro-apoptotic and pro-survival pathways. The prevalence of post-COVID-19 pulmonary fibrosis (PCPF) is 44.9%, along with an alarming increase in "Coronavirus Disease 2019" (COVID-19) comorbidities. Fibrotic airway remodeling and declined lung function are the common endpoints of SARS-CoV-2 infection and IPF. Flavonoids are available in our dietary supplements and exhibit medicinal properties. Apigenin is a flavonoid found in plants, including chamomile, thyme, parsley, garlic, guava, and broccoli, and regulates several cellular functions, such as oxidative stress, ER stress, and fibrotic responses. In this study, we focus on the IPF and COVID-19 pathogenesis and the potential role of Apigenin in addressing disease progression.

Therapeutic Strategies for Idiopathic Pulmonary Fibrosis - Thriving Present and Promising Tomorrow

Idiopathic pulmonary fibrosis (IPF) is a continuous, progressive, and lethal age-related respiratory disease. It is characterized by condensed and rigid lung tissue, which leads to a decline in the normal functioning of the lungs. The pathophysiology of IPF has still not been completely elucidated, so current strategies are lagging behind with respect to improving the condition of patients with IPF and increasing their survival rate. The desire for a better understanding of the pathobiology of IPF and its early detection has led to the identification of various biomarkers associated with IPF. The use of drugs such as pirfenidone and nintedanib as a safe and effective treatment alternative have marked a new chapter in the treatment of IPF. However, nonpharmacological therapies, involving long-term oxygen therapy, transplantation of the lungs, pulmonary rehabilitation, ventilation, and palliative care for cough and dyspnea, are still considered to be beneficial as supplementary methods for IPF therapy. A major risk factor for IPF is aging, with associated hallmarks such as telomere attrition, senescence, epigenetic drift, stem cell exhaustion, loss of proteostasis, and mitochondrial dysfunction. These are promising earmarks for the development of potential therapy for the disease. In this review, we have discussed current and emerging novel therapeutic strategies for IPF, especially for targets associated with age-related mechanisms.

Enhanced Detection of Early Pulmonary Fibrosis Disease Using 68Ga-FAPI-LM3 PET

Early detection of pulmonary fibrosis is a critical yet insufficiently met clinical necessity. This study evaluated the effectiveness of FAPI-LM3, a 68Ga-radiolabeled heterobivalent molecular probe that targets fibroblast activating protein (FAP) and somatostatin receptor 2 (SSTR2), in the early detection of pulmonary fibrosis, leveraging its potential for early disease identification. A bleomycin-induced early pulmonary fibrosis model was established in C57BL/6 mice for 7 days. FAP and SSTR2 expression levels were quantitatively assessed in human idiopathic pulmonary fibrosis lung tissue samples and bleomycin-treated mouse lung tissues by using western blotting, real-time quantitative PCR (RT-qPCR), and immunofluorescence techniques. The diagnostic performance of FAPI-LM3 was investigated by synthesizing monomeric radiotracers 68Ga-FAPI-46 and 68Ga-DOTA-LM3 alongside the heterobivalent probe 68Ga-FAPI-LM3. These imaging radiopharmaceuticals were used in small-animal PET to compare their uptake in fibrotic and normal lung tissues. Results indicated significant upregulation of FAP and SSTR2 at both RNA and protein levels in fibrotic lung tissues compared with that in normal controls. PET imaging demonstrated significantly enhanced uptake of the 68Ga-FAPI-LM3 probe in fibrotic lung tissues, with superior visual effects compared to monomeric tracers. At 60 min postinjection, early stage fibrotic tissues (day 7) demonstrated low-to-medium uptake of monomeric probes, including 68Ga-DOTA-LM3 (0.45 ± 0.04% ID/g) and 68Ga-FAPI-46 (0.78 ± 0.09% ID/g), whereas the uptake of the heterobivalent probe 68Ga-FAPI-LM3 (1.90 ± 0.10% ID/g) was significantly higher in fibrotic lesions than in normal lung tissue. Blockade experiments confirmed the specificity of 68Ga-FAPI-LM3 uptake, which was attributed to synergistic targeting of FAP and SSTR2. This study demonstrates the potential of 68Ga-FAPI-LM3 for early pulmonary fibrosis detection via molecular imaging, offering significant benefits over monomeric tracers 68Ga-FAPI-46 and 68Ga-DOTA-LM3. This strategy offers new possibilities for noninvasive and precise early detection of pulmonary fibrosis.

Network pharmacology and in silico approaches to uncover multitargeted mechanism of action of Zingiber zerumbet rhizomes for the treatment of idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a disease with high mortality, and there are only two specific drugs available for therapeutic management with limitations. The study aims to identify comprehensive therapeutic mechanisms of Zingiber zerumbet rhizomes (ZZR) to treat IPF by using network pharmacology followed battery of in silico studies.

Methods

The protein-protein interaction network was developed using Cytoscape to obtain core disease targets involved in IPF and their interactive molecules of ZZR. Based on the pharmacophore properties of phytomolecules from ZZR, the drug targets in IPF were explored. Protein-protein interaction network was built in Cytoscape to screen potential targets and components of ZZR. Molecular docking and dynamics were conducted as an empirical study to investigate the mechanism explored through network pharmacology in relation to the hub targets.

Results

The network analysis conferred kaempferol derivatives that had demonstrated a promising therapeutic effect on the perturbed, robust network hubs of TGF-β1, EGFR, TNF-α, MMP2 & MMP9 reported to alter the biological process of mesenchymal transition, myofibroblast proliferation, and cellular matrix deposition in pulmonary fibrosis. The phytomolecules of ZZR act on two major significant pathways, namely the TGF-β-signaling pathway and the FOXO-signaling pathway, to inhibit IPF. Confirmational molecular docking and dynamics simulation studies possessed good stability and interactions of the protein-ligand complexes by RMSD, RMSF, rGyr, SASA, and principal component analysis (PCA). Validated molecular docking and dynamics simulations provided new insight into exploring the mechanism and multi-target effect of ZZR to treat pulmonary fibrosis by restoring the alveolar phenotype through cellular networking.

Conclusions

Network pharmacology and in silico studies confirm the multitargeted activity of ZZR in the treatment of IPF. Further in vitro and in vivo studies are to be conducted to validate these findings.

Sumatriptan mitigates bleomycin-induced lung fibrosis in male rats: Involvement of inflammation, oxidative stress and α-SMA

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a fibrotic lung condition that produces symptoms including coughing which may cause by excessive accumulation of scar tissue inflammatory and oxidative stress exacerbation. Sumatriptan, utilized for migraine treatment as a selective 5-HT1B/1D receptor agonist, has demonstrated significant anti-inflammatory and antioxidant properties in multiple preclinical investigations. Operating primarily on serotonin receptors, sumatriptan leverages the diverse physiological functions of serotonin, playing a pivotal role in regulating both inflammation and oxidative stress which is particularly relevant in the context of IPF.

MATERIALS & METHODS

Thirty-five male Wistar rats were divided to five group, including: Sham (without IPF induction), control (BLM 5 mg/kg, intraperitoneally), and three fibrosis group with sumatriptan (0.5, 1, and 3 mg/kg, i.p. for 2 weeks) administration. IPF was induced by injection of BLM (single dose, 5 mg/kg intratracheally). Lung tissues were separated for measurement of myeloperoxidase (MPO) as an oxidative stress hallmark, and tumor necrosis factor-α (TNF-α), interleukin-1β (IL-β), and transforming growth factor-β (TGF-β) as inflammatory markers as well as alpha smooth muscle actin (α-SMA). Also, for histological investigations, tissue damages were assessed by Hematoxylin-eosin (H&E) and Masson's trichrome staining method.

RESULTS

BLM-induced fibrosis could increase α-SMA, MPO, TNF-α, IL-1β, and TGF-β, while treatment with sumatriptan has reversed the α-SMA, MPO, and IL-1β levels. Moreover, the results of H&E and Masson's trichrome staining indicated that sumatriptan (1 and 3 mg/kg) reduced tissue damages, alveolar wall thickness, collagen accumulation, and pulmonary fibrosis induced by BLM.

CONCLUSION

According to the data achieved from this study, Sumatriptan appears to have therapeutic benefits in IPF, possibly via reducing α-SMA as well as inflammation and the toxicity caused by oxidative stress.

Ivermectin ameliorates bleomycin-induced lung fibrosis in male rats by inhibiting the inflammation and oxidative stress

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a pulmonary fibrotic disease characterized by a poor prognosis, which its pathogenesis involves the accumulation of abnormal fibrous tissue, inflammation, and oxidative stress. Ivermectin, a positive allosteric modulator of GABAA receptor, exerts anti-inflammatory and antioxidant properties in preclinical studies. The present study investigates the potential protective effects of ivermectin treatment in rats against bleomycin-induced IPF.

MATERIALS AND METHODS

The present study involved 42 male Wistar rats, which were divided into five groups: control (without induction of IPF), bleomycin (IPF-induced by bleomycin 2.5 mg/kg, by intratracheal administration), and three fibrosis groups receiving ivermectin (0.5, 1, and 3 mg/kg). lung tissues were harvested for measurement of oxidative stress [via myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione (GSH)] and inflammatory markers (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β], and transforming growth factor-β [TGF-β]). Histological assessments of tissue damage were performed using hematoxylin-eosin (H&E) and Masson's trichrome staining methods.

RESULTS

The induction of fibrosis via bleomycin was found to increase levels of MPO as well as TNF-α, IL-1β, and TGF-β while decrease SOD activity and GSH level. Treatment with ivermectin at a dosage of 3 mg/kg was able to reverse the effects of bleomycin-induced fibrosis on these markers. In addition, results from H&E and Masson's trichrome staining showed that ivermectin treatment at this same dose reduced tissue damage and pulmonary fibrosis.

CONCLUSION

The data obtained from this study indicate that ivermectin may have therapeutic benefits for IPF, likely due to its ability to reduce inflammation and mitigate oxidative stress-induced toxicity.

Circulating biomarker analyses in a longitudinal cohort of patients with IPF

Idiopathic pulmonary fibrosis (IPF) is an incurable interstitial lung disease characterized by fibrosis. Two FDA-approved drugs, pirfenidone and nintedanib, only modestly prolong survival. In this study, we asked whether levels of select circulating biomarkers in patients with IPF demonstrated changes in response to treatment over time and whether treatment with pirfenidone and nintedanib led to differential biomarker expression. Serial plasma samples from 48 patients with IPF on usual treatment and six healthy volunteers were analyzed to identify differentially expressed blood protein. Hypothesis-driven potential biomarker selection was based on recent literature, internal preclinical data, and the PROLIFIC Consortium (Schafer P. 6th Annual IPF Summit. Boston, MA, 2022) proposed biomarkers of pulmonary fibrosis. We compared our findings to public databases to provide insights into relevant signaling pathways in IPF. Of the 26 proteins measured, we found that 11 (SP-D, TIMP1, MMP7, CYFRA21-1, YKL40, CA125, sICAM, IP-10, MDC, CXCL13) were significantly elevated in patients with IPF compared with healthy volunteers but their levels did not significantly change over time. In the IPF samples, seven proteins were elevated in the treatment group compared with the no-treatment group. However, protein profiles were not distinguishable between patients on pirfenidone versus nintedanib. We demonstrated that most proteins differentially detected in our samples were predicted to be secreted from the lung epithelial or interstitial compartments. However, a significant minority of the proteins are not known to be transcriptionally expressed by lung cells, suggesting an ongoing systemic response. Understanding the contributions of the systemic response in IPF may be important as new therapeutics are developed.NEW & NOTEWORTHY In this study, we confirmed protein expression differences in only a subset of predicted biomarkers from IPF and control subjects. Most differentially expressed proteins were predicted to be secreted from lung cells. However, a significant minority of the proteins are not known to be transcriptionally expressed by lung cells, suggesting an ongoing systemic response. The contributions of the systemic response in IPF may be important as new therapeutics are developed.

Protective effects and mechanism of curcumin in animal models of pulmonary fibrosis: a preclinical systematic review and meta-analysis

Introduction: At present, there is a lack of effective treatment for pulmonary fibrosis (PF), and a number of studies have confirmed that curcumin (CUR) has a good effect on PF. Research Qusetion: Is CUR effective in preclinical trials for PF and what is its mechanism of action? Methods: Animal reports of PF treated with CUR were searched from Pubmed, Embase, Web of Science and Cochrane Library from 1 January 2000 to 19 April 2023 to compare CUR treatment of PF with a no-intervention model group. A previous registration (nsply registration number: INPLASY202360084) of this review protocol was undertaken. Results: The meta-analysis included 27 publications and 29 studies involving 396 animals. CUR significantly improved the degree of fibrosis, levels of inflammation, and oxidative imbalances in lung tissue in animal models of PF. In terms fibrosis, such as HYP content (SMD = -4.96; 95% CI = -6.05 to -3.87; p = 0.000).In terms of inflammatory indicators, such as MPO activity (SMD = -2.12; 95% CI = -4.93 to 0.69; p = 0.000). In terms of oxidation index, such as MDA (SMD = -5.63; 95% CI = -9.66 to -1.6; p = 0.000). Conclusion: CUR significantly improved the degree of fibrosis, levels of inflammation, and oxidative imbalances in lung tissue in animal models of PF. Due to the quantitative and qualitative limitations of current research, more high-quality studies are needed to verify the above conclusion.

ErbB4 promotes M2 activation of macrophages in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common and fatal diffuse fibrotic lung disease accompanied by macrophage M2 activation. ErbB4 is involved in and affects the process of inflammation. In this study, we determined that the mRNA level and protein expression of ErbB4 and M2 cytokine members were increased in the serum of IPF patients. In mouse alveolar macrophage MH-S cells, after knocking down ErbB4 by siRNA, the mRNA level and protein expression of M2 activator induced by interleukin (IL)-4 were decreased compared with the control group. Activating by ErbB4 agonist neuromodulatory protein (NRG)-1, IL-4-induced M2 program was promoted. Mechanistically, treated with NRG-1 in MH-S cells, the phosphorylation level of Akt did not change, while the phosphorylation level of ERK increased. Using SCH772984 to inhibit ERK pathway, the increasing IL-4-induced M2 activation by NRG-1 was inhibited, and the high level of M2 activator protein expression and mRNA expression was restored. Collectively, our data support that ErbB4 and M2 programs are implicated in IPF, and ErbB4 participates in the regulation of M2 activation induced by IL-4 through the ERK pathway.

Monocytes and macrophages: emerging mechanisms and novel therapeutic targets in pulmonary fibrosis

Pulmonary fibrosis results from a plethora of abnormal pathogenetic events. In idiopathic pulmonary fibrosis (IPF), inhalational, environmental, or occupational exposures in genetically and epigenetically predisposed individuals trigger recurrent cycles of alveolar epithelial cell injury, activation of coagulation pathways, chemoattraction, and differentiation of monocytes into monocyte-derived alveolar macrophages (Mo-AMs). When these events happen intermittently and repeatedly throughout the individual's life cycle, the wound repair process becomes aberrant leading to bronchiolization of distal air spaces, fibroblast accumulation, extracellular matrix deposition, and loss of the alveolar-capillary architecture. The role of immune dysregulation in IPF pathogenesis and progression has been underscored in the past mainly after the disappointing results of immunosuppressant use in IPF patients; however, recent reports highlighting the prognostic and mechanistic roles of monocytes and Mo-AMs revived the interest in immune dysregulation in IPF. In this review, we will discuss the role of these cells in the onset and progression of IPF, as well as potential targeted therapies.

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.

Discovery of the novel Benzo[b]thiophene 1,1-dioxide derivatives as a potent STAT3 inhibitor against idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease of unknown aetiology with limited treatment options. Currently, only two drugs, nintedanib and pirfenidone, are approved for the clinical treatment of IPF, but their efficacies are not satisfactory. Previous studies have shown that STAT3 might be a promising therapeutic target for IPF. Here, we designed several series of compounds and finally synthesized a total of 48 novel compounds as potential STAT3 inhibitors. Notably, compound 10K was the most promising compound with excellent inhibitory activity against STAT3 phosphorylation. Subsequently, the anti-pulmonary fibrosis effect of 10K was further investigated by TGF-β1-stimulated in vitro cell assay and bleomycin (BLM)-induced pulmonary fibrosis animal models. Specifically, compound 10K inhibited the TGF-β1 induced fibrotic response and blocked the epithelial-mesenchymal transition (EMT) of A549 cells, and its inhibitory effect was significantly better than that of Stattic. In addition, after oral administration of 10K, the symptoms of IPF in the lung tissue in the prevention and treatment mouse models were significantly reversed, and the efficacy was comparable to that of nintedanib. Moreover, 10K improved BLM-induced imbalance of immune microenvironment in lung tissue. Taken together, these results suggest that 10K could be a potential STAT3 inhibitor for the treatment of IPF.

The Challenging Diagnosis of Interstitial Lung Disease in Children-One Case Report and Literature Review

Childhood interstitial lung disease (chILD) includes a heterogeneous spectrum of rare respiratory disorders in children associated with substantial morbi-mortality. Interstitial tissue, and other pulmonary structures, epithelium, blood vessels, or pleura are involved, resulting in a restrictive lung disfunction. Respiratory symptoms set in progressively and are often subtle, making thorough clinical history and physical examination fundamental. The etiology often is obscure. The clinical presentation mimics pneumonia or asthma, leading to a diagnostic delay. Challenging diagnosis may require genetic tests, bronchoalveolar lavage, or lung biopsy. Alongside general supportive therapeutic measures, anti-inflammatory, immunosuppressive or antifibrotic agents may be used, based on data derived from adult studies. However, if accurate diagnosis and treatment are delayed, irreversible chronic respiratory failure may ensue, impacting prognosis. The most frequent chILD is hypersensitivity pneumonitis (HP), although it is rare in children. HP is associated with exposure to an environmental antigen, resulting in inflammation of the airways. Detailed antigen exposure history and identification of the inciting trigger are the cornerstones of diagnostic. This article provides the current state of chILD, revealing specific features of HP, based on a clinical case report of a patient admitted in our clinic, requiring extensive investigations for diagnosis, with a favorable long-term outcome.

Idiopathic Pulmonary Fibrosis: What do we Know about the Role of Occupational and Environmental Determinants? A Systematic Literature Review and Meta-Analysis

The objectives of this systematic review of original articles published up until August 2021 and meta-analyses were to identify the links between occupational and non-occupational environmental exposures, types of occupations and idiopathic pulmonary fibrosis (IPF). Sixteen selected case-control studies were qualified as good level with Newcastle-Ottawa quality assessment scale. Sensitivity analyses highlighted the role of choice of control group, tobacco adjustment and diagnostic tools. Significantly increased risks of IPF were observed (OR (95%CI): for metals (1.42(1.05-1.92)), wood (OR:1.32(1.02-1.71)), and general dust (OR:1.32(1.08-1.63)) exposures. Subgroup analyses found a significantly elevated risk for: hardwood (OR:1.75 (1.13-2.70)), organic dusts (OR:1.72 (1.20-2.46)) and pesticides (OR:2.30 (1.30-4.08)), while no significant change was noted for softwoods and solvents. Smoking adjustments: general dust (1.45 (1.04-2.03)/organic dust (2.5 (1.49-4.22)/metals (1.87 (1.16-3)/wood dust OR: 1.16 (0.86-1.61)/pesticide exposure 2.4 (0.84-6.9) were calculated. Among agricultural workers, the risk was also increased (OR:2.06 (1.02-4.16)). Few environmental data were available and no significant associations detected. Thus, these meta-analyses highlighted the role of some occupational exposures in IPF occurrence. A more accurate and thorough assessment of exposures over the entire working life as well as on the duration and intensity of exposure and complex of multi-pollutant exposure is needed in future research and clinical practice.

Disturbance of serum lipid metabolites and potential biomarkers in the Bleomycin model of pulmonary fibrosis in young mice

Background

Altered metabolic pathways have recently been considered as potential drivers of idiopathic pulmonary fibrosis (IPF) for the study of drug therapeutic targets. However, our understanding of the metabolite profile during IPF formation is lacking.

Methods

To comprehensively characterize the metabolic disorders of IPF, a mouse IPF model was constructed by intratracheal injection of bleomycin into C57BL/6J male mice, and lung tissues from IPF mice at 7 days, 14 days, and controls were analyzed by pathology, immunohistochemistry, and Western Blots. Meanwhile, serum metabolite detections were conducted in IPF mice using LC–ESI–MS/MS, KEGG metabolic pathway analysis was applied to the differential metabolites, and biomarkers were screened using machine learning algorithms.

Results

We analyzed the levels of 1465 metabolites and found that more than one-third of the metabolites were altered during IPF formation. There were 504 and 565 metabolites that differed between M7 and M14 and controls, respectively, while 201 differential metabolites were found between M7 and M14. In IPF mouse sera, about 80% of differential metabolite expression was downregulated. Lipids accounted for more than 80% of the differential metabolite species with down-regulated expression. The KEGG pathway enrichment analysis of differential metabolites was mainly enriched to pathways such as the metabolism of glycerolipids and glycerophospholipids. Eight metabolites were screened by a machine learning random forest model, and receiver operating characteristic curves (ROC) assessed them as ideal diagnostic tools.

Conclusions

In conclusion, we have identified disturbances in serum lipid metabolism associated with the formation of pulmonary fibrosis, contributing to the understanding of the pathogenesis of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01972-6.

Management of musculoskeletal pain in patients with idiopathic pulmonary fibrosis: a review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic, and fatal interstitial lung disease (ILD) of unknown etiology that primarily affects the elderly. Patients with IPF suffer from a heavy symptom burden and usually have a poor quality of life. Dyspnea and dry cough are predominant symptoms of IPF. Although pain is not considered one of the main symptoms of IPF, it can occur for a variety of reasons, such as hypoxia, coughing, muscle and nerve damage, deconditioning, and steroid use. The prevalence of pain in IPF patients varies greatly, ranging from around 30 to 80%, with the prevalence being estimated mostly among patients in the end-of-life period. It manifests itself in the form of muscle pain, joint discomfort, or back and chest pain. Approaches to the treatment of chronic musculoskeletal pain in patients with IPF include pharmacological and non-pharmacological measures that are also important to optimize the treatment of other symptoms (dyspnea and cough) and the optimal treatment of comorbidities. Given the scarcity of data on this symptom in the literature, this article summarizes what is currently known about the etiology and treatment of musculoskeletal pain in IPF.

Fibro-CoSANet: pulmonary fibrosis prognosis prediction using a convolutional self attention network

Idiopathic pulmonary fibrosis (IPF) is a restrictive interstitial lung disease that causes lung function decline by lung tissue scarring. Although lung function decline is assessed by the forced vital capacity (FVC), determining the accurate progression of IPF remains a challenge. To address this challenge, we proposed Fibro-CoSANet, a novel end-to-end multi-modal learning based approach, to predict the FVC decline. Fibro-CoSANet utilized computed tomography images and demographic information in convolutional neural network frameworks with a stacked attention layer. Extensive experiments on the OSIC Pulmonary Fibrosis Progression Dataset demonstrated the superiority of our proposed Fibro-CoSANet by achieving new state-of-the-art modified Laplace log-likelihood score of -6.68. This network may benefit research areas concerned with designing networks to improve the prognostic accuracy of IPF. The source-code for Fibro-CoSANet is available at: https://github.com/zabir-nabil/Fibro-CoSANet.

Stable Long-Term Culture of Human Distal Airway Stem Cells for Transplantation

There is a population of p63⁺/Krt5⁺ distal airway stem cells (DASCs) quiescently located in the airway basal epithelium of mammals, responding to injury and airway epithelial regeneration. They hold the ability to differentiate into multiple pulmonary cell types and can repopulate the epithelium after damage. The current study aims at gaining further insights into the behavior and characteristics of the DASCs isolated from the patient lung and exploring their clinical translational potential. Human DASCs were brushed off through the bronchoscopic procedure and expanded under the pharmaceutical-grade condition. Their phenotype stability in long-term cell culture was analyzed, followed by safety evaluation and tumorigenic analysis using multiple animal models including rodents and nonhuman primate. The chimerism of the human-mouse lung model indicated that DASC pedigrees could give rise to multiple epithelial types, including type I alveolar cells as well as bronchiolar secretory cells, to regenerate the distal lung. Taken together, the results suggested that DASC transplantation could be a promising therapeutic approach for unmet needs in respiratory medicine including the COVID-19-related diseases.

Pterostilbene alleviates pulmonary fibrosis by regulating ASIC2

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a serious chronic disease of the respiratory system, but its current treatment has certain shortcomings and adverse effects. In this study, we evaluate the antifibrotic activity of pterostilbene (PTE) using an in vitro IPF model induced by transforming growth factor (TGF)-β1.

METHODS

A549 and alveolar epithelial cells (AECs) were incubated with 10 ng/ml TGF-β1 to induce lung fibroblast activation. Then, 30 μmol/L of PTE was used to treat these cells. The epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) accumulation, and autophagy in cells were evaluated by western blot. Apoptosis was validated by flow cytometry analysis and western blot. Transcriptome high-throughput sequencing was performed on A549 cells incubated with TGF-β1 alone or TGF-β1 and PTE (TGF-β1 + PTE), and differentially expressed genes in PTE-treated cells were identified. The acid sensing ion channel subunit 2 (ASIC2) overexpression plasmid was used to rescue the protein levels of ASIC2 in A549 and AECs.

RESULTS

TGF-β1 caused EMT and ECM accumulation, and blocked the autophagy and apoptosis of A549 and AECs. Most importantly, 30 μmol/L of PTE inhibited pulmonary fibrosis induced by TGF-β1. Compared with TGF-β1, PTE inhibited EMT and ECM accumulation and rescued cell apoptosis and autophagy. The results of transcriptome high-throughput sequencing revealed that PTE greatly reduced the protein level of ASIC2. Compared with the TGF-β1 + PTE group, the transfection of ASIC2 overexpression plasmid stimulated the EMT and ECM accumulation and inhibited apoptosis and autophagy, suggesting that PTE inhibited pulmonary fibrosis by downregulating ASIC2.

CONCLUSIONS

This study suggests that PTE and ASIC2 inhibitors may have potential as IPF treatments in the future.

Adipose Stromal Cell-Secretome Counteracts Profibrotic Signals From IPF Lung Matrices

Introduction: Idiopathic pulmonary fibrosis (IPF) is a fibrotic lung disease characterized by excess deposition and altered structure of extracellular matrix (ECM) in the lungs. The fibrotic ECM is paramount in directing resident cells toward a profibrotic phenotype. Collagens, an important part of the fibrotic ECM, have been shown to be structurally different in IPF. To further understand the disease to develop better treatments, the signals from the ECM that drive fibrosis need to be identified. Adipose tissue-derived stromal cell conditioned medium (ASC-CM) has demonstrated antifibrotic effects in animal studies but has not been tested in human samples yet. In this study, the collagen structural integrity in (fibrotic) lung tissue, its interactions with fibroblasts and effects of ASC-CM treatment hereon were studied. Methods: Native and decellularized lung tissue from patients with IPF and controls were stained for denatured collagen using a collagen hybridizing peptide. Primary lung fibroblasts were seeded into decellularized matrices from IPF and control subjects and cultured for 7 days in the presence or absence of ASC-CM. Reseeded matrices were fixed, stained and analyzed for total tissue deposition and specific protein expression. Results: In both native and decellularized lung tissue, more denatured collagen was observed in IPF tissue compared to control tissue. Upon recellularization with fibroblasts, the presence of denatured collagen was equalized in IPF and control matrices, whereas total ECM was higher in IPF matrices than in the control. Treatment with ASC-CM resulted in less ECM deposition, but did not alter the levels of denatured collagen. Discussion: Our data showed that ASC-CM can inhibit fibrotic ECM-induced profibrotic behavior of fibroblasts. This process was independent of collagen structural integrity. Our findings open up new avenues for ASC-CM to be explored as treatment for IPF.

The development of HEC-866 and its analogues for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with a typical survival time between three to five years. Two drugs, pirfenidone and nintedanib have been approved for the treatment of IPF, but they have limited efficacy. Thus, the development of new drugs to treat IPF is an urgent medical need. In this paper we report the discovery of a series of orally active pyrimidin-4(3H)-one analogs which exhibit potent activity in in vitro assays. Among them, HEC-866 showed promising efficacy in rat IPF models. Since HEC-866 also had good oral bioavailability, a long half-life and favorable long-term safety profiles, it was selected for further clinical evaluation.

Andrographolide alleviates bleomycin-induced NLRP3 inflammasome activation and epithelial-mesenchymal transition in lung epithelial cells by suppressing AKT/mTOR signaling pathway

Background

Andrographolide (Andro), a diterpenoid extracted from Andrographis paniculata, has been shown to attenuate pulmonary fibrosis in rodents; however, the potential mechanisms remain largely unclear. This study investigated whether and how Andro alleviates bleomycin (BLM)-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation and epithelial-mesenchymal transition (EMT) in the lung epithelial cells.

Methods

The in vivo effects of Andro were evaluated in a rat model of BLM-induced pulmonary fibrosis. The roles of Andro in BLM-induced NLRP3 inflammasome activation, EMT and AKT/mTOR signaling were investigated using human alveolar epithelial A549 cells.

Results

We found that Andro significantly alleviated pulmonary edema and histopathological changes, decreased weight loss, and reduced collagen deposition. Andro downregulated the levels of NLRP3, the adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC), and Caspase-1 in the lungs of BLM-treated rats, suggesting the inhibitory effect of Andro on NLRP3 inflammasome activation in vivo. Additionally, the symptoms of BLM-mediated EMT phenotype in the lung were also attenuated after Andro administration. In vitro, Andro also markedly inhibited BLM-induced NLRP3 inflammasome activation and EMT in A549 cells. Moreover, Andro inhibited BLM-induced phosphorylation of AKT and mTOR in A549 cells, suggesting that AKT/mTOR inactivation mediates Andro-induced effects on BLM-induced NLRP3 inflammasome activation and EMT.

Conclusions

These data indicate that Andro can reduce BLM-induced pulmonary fibrosis through suppressing NLRP3 inflammasome activation and EMT in lung epithelial cells via AKT/mTOR signaling pathway.

The Protective Effects of Nebulized Nano-Curcumin Against Bleomycin-Induced Pulmonary Fibrosis in Rats

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fatal disease affecting the lung, and currently there is no efficient therapy for this condition. Curcumin, as a natural anti-inflammatory and antioxidant agent, could repress the pulmonary fibrosis (PF) caused by Bleomycin (BLM). Objectives: The aim of the research was to evaluate the protective activity of a nano-formulation of curcumin administered by inhalation on BLM-induced PF in rats. Methods: Eighty rats were randomly divided into eight experimental groups. Group one (control) that received saline intratracheally (IT) and subjected to vehicle inhalation. Group two to eight each received a single dose of BLM (5 IU/kg, IT) along with vehicle inhalation, oral prednisolone, oral curcumin, curcumin inhalation, and nano-curcumin inhalation with the doses of 50, 100, and 200 µg/kg, respectively. In the control and other groups, BLM was injected intratracheally on the first day of the experiment. In the treatment groups, curcumin suspension was prepared in distilled water and applied through nebulization for 21 consecutive days after BLM intratracheal administration. Then the rats were euthanized, and inflammatory cytokines (TNF-α, TGF-β, PDGF), hydroxyproline, and IL-10 (as a protective cytokine) were measured. Also, lung histopathological features were examined. Results: The synthesized nano-formulation reduced the overall hydroxyproline content of lungs in BLM-treated rats (P < 0.002). In addition, TNF-α, TGF-β, and PDGF levels significantly increased in the lungs of BLM-instilled rats (P < 0.001). However, the nano-formulation of curcumin (200 µg/kg) significantly decreased the levels of these inflammatory cytokines (P < 0.001) and increased IL-10 level (P = 0.0144) compared with the control group. Conclusions: The nebulization of nano-curcumin is suggested as a novel approach for the treatment of PF induced by BLM in rats. Our findings revealed that the inhalation (as a safe local drug delivery system approach) of the nano-curcumin at a dose of 200 µg/kg (formulated by cyclodextrin) could effectively protect the lung against PF.

Human antigen R promotes lung fibroblast differentiation to myofibroblasts and increases extracellular matrix production

Idiopathic pulmonary fibrosis (IPF) is a disease of progressive scarring caused by excessive extracellular matrix (ECM) deposition and activation of α-SMA-expressing myofibroblasts. Human antigen R (HuR) is an RNA binding protein that promotes protein translation. Upon translocation from the nucleus to the cytoplasm, HuR functions to stabilize messenger RNA (mRNA) to increase protein levels. However, the role of HuR in promoting ECM production, myofibroblast differentiation, and lung fibrosis is unknown. Human lung fibroblasts (HLFs) treated with transforming growth factor β1 (TGF-β1) showed a significant increase in translocation of HuR from the nucleus to the cytoplasm. TGF-β-treated HLFs that were transfected with HuR small interfering RNA had a significant reduction in α-SMA protein as well as the ECM proteins COL1A1, COL3A, and FN1. HuR was also bound to mRNA for ACTA2, COL1A1, COL3A1, and FN. HuR knockdown affected the mRNA stability of ACTA2 but not that of the ECM genes COL1A1, COL3A1, or FN. In mouse models of pulmonary fibrosis, there was higher cytoplasmic HuR in lung structural cells compared to control mice. In human IPF lungs, there was also more cytoplasmic HuR. This study is the first to show that HuR in lung fibroblasts controls their differentiation to myofibroblasts and consequent ECM production. Further research on HuR could assist in establishing the basis for the development of new target therapy for fibrotic diseases, such as IPF.

Non-invasive IGFBP1, IGFBP2 biomarkers as predictors and outcomes of usual interstitial pneumonia (UIP) therapeutic response

Background

Usual interstitial pneumonia (UIP) is a fatal disease that is associated with poor prognosis and survival. Several growth factors such as IGFs (insulin-like growth factors) and IGFBPs (insulin-like growth factor binding proteins) seem to take part to this pathogenesis.

Pirfenidone is an immunosuppressant drug that is thought to have anti-inflammatory and anti-fibrotic effects both in vitro and in vivo.

Objective

To assess IGFBP1 and IGFBP2 as non-invasive biomarkers for prediction and outcomes of UIP clinical activity and therapeutic response to the anti-fibrotic pirfenidone.

Results

Serum levels of IGFBP1 and IGFBP2 were significantly higher in the UIP group than in the healthy subjects (p ≤ 0.005). After 6 months therapy, UIP patients were divided into 2 groups according to improvement in MRC dyspnea grading into clinically improved and non-improved groups. 6MWT and SPaO2 were significantly improved in the clinically improved group compared to the non-improved one with no differences as regards other parameters (p < 0.0001). Both IGFBP1 and IGFBP2 were significantly decreased in serum while only IGFBP2 was decreased in BAL of all UIP after completing 12 months therapy.

Conclusion

IGFBP1 and IGFBP2 were increased in active UIP patients and reduced after 12 months anti-fibrosing therapy. IGFBPs may be promising biomarkers and predictors of response to therapy in UIP.

Role of various imbalances centered on alveolar epithelial cell/fibroblast apoptosis imbalance in the pathogenesis of idiopathic pulmonary fibrosis

There have been recent extensive studies and rapid advancement on the pathogenesis underlying idiopathic pulmonary fibrosis (IPF), and intricate pathogenesis of IPF has been suggested. The purpose of this study was to clarify the logical relationship between these mechanisms. An extensive search was undertaken of the PubMed using the following keywords: “etiology,” “pathogenesis,” “alveolar epithelial cell (AEC),” “fibroblast,” “lymphocyte,” “macrophage,” “epigenomics,” “histone,” acetylation,” “methylation,” “endoplasmic reticulum stress,” “mitochondrial dysfunction,” “telomerase,” “proteases,” “plasminogen,” “epithelial-mesenchymal transition,” “oxidative stress,” “inflammation,” “apoptosis,” and “idiopathic pulmonary fibrosis.” This search covered relevant research articles published up to April 30, 2020. Original articles, reviews, and other articles were searched and reviewed for content; 240 highly relevant studies were obtained after screening. IPF is likely the result of complex interactions between environmental, genetic, and epigenetic factors: environmental exposures affect epigenetic marks; epigenetic processes translate environmental exposures into the regulation of chromatin; epigenetic processes shape gene expression profiles; in turn, an individual's genetic background determines epigenetic marks; finally, these genetic and epigenetic factors act in concert to dysregulate gene expression in IPF lung tissue. The pathogenesis of IPF involves various imbalances including endoplasmic reticulum, telomere length homeostasis, mitochondrial dysfunction, oxidant/antioxidant imbalance, Th1/Th2 imbalance, M1–M2 polarization of macrophages, protease/antiprotease imbalance, and plasminogen activation/inhibition imbalance. These affect each other, promote each other, and ultimately promote AEC/fibroblast apoptosis imbalance directly or indirectly. Excessive AEC apoptosis and impaired apoptosis of fibroblasts contribute to fibrosis. IPF is likely the result of complex interactions between environmental, genetic, and epigenetic factors. The pathogenesis of IPF involves various imbalances centered on AEC/fibroblast apoptosis imbalance.

The ER Stress/UPR Axis in Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis

Cellular protein homeostasis in the lungs is constantly disrupted by recurrent exposure to various external and internal stressors, which may cause considerable protein secretion pressure on the endoplasmic reticulum (ER), resulting in the survival and differentiation of these cell types to meet the increased functional demands. Cells are able to induce a highly conserved adaptive mechanism, known as the unfolded protein response (UPR), to manage such stresses. UPR dysregulation and ER stress are involved in numerous human illnesses, such as metabolic syndrome, fibrotic diseases, and neurodegeneration, and cancer. Therefore, effective and specific compounds targeting the UPR pathway are being considered as potential therapies. This review focuses on the impact of both external and internal stressors on the ER in idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) and discusses the role of the UPR signaling pathway activation in the control of cellular damage and specifically highlights the potential involvement of non-coding RNAs in COPD. Summaries of pathogenic mechanisms associated with the ER stress/UPR axis contributing to IPF and COPD, and promising pharmacological intervention strategies, are also presented.

Toward Regulatory Effects of Curcumin on Transforming Growth Factor-Beta Across Different Diseases: A Review

Immune response, proliferation, migration and angiogenesis are juts a few of cellular events that are regulated by transforming growth factor-β (TGF-β) in cells. A number of studies have documented that TGF-β undergoes abnormal expression in different diseases, e.g., diabetes, cancer, fibrosis, asthma, arthritis, among others. This has led to great fascination into this signaling pathway and developing agents with modulatory impact on TGF-β. Curcumin, a natural-based compound, is obtained from rhizome and roots of turmeric plant. It has a number of pharmacological activities including antioxidant, anti-inflammatory, anti-tumor, anti-diabetes and so on. Noteworthy, it has been demonstrated that curcumin affects different molecular signaling pathways such as Wnt/β-catenin, Nrf2, AMPK, mitogen-activated protein kinase and so on. In the present review, we evaluate the potential of curcumin in regulation of TGF-β signaling pathway to corelate it with therapeutic impacts of curcumin. By modulation of TGF-β (both upregulation and down-regulation), curcumin ameliorates fibrosis, neurological disorders, liver disease, diabetes and asthma. Besides, curcumin targets TGF-β signaling pathway which is capable of suppressing proliferation of tumor cells and invading cancer cells.

DNA Methylation in Pulmonary Fibrosis

DNA methylations, including global methylation pattern and specific gene methylation, are associated with pathogenesis and progress of pulmonary fibrosis. This chapter illustrates alteration of DNA methylation in pulmonary fibrosis as a predictive or prognostic factor. Treatment with the DNA methylation inhibitors will be an emerging anti-fibrosis therapy, although we are still in the pre-clinical stage of using epigenetic markers as potential targets for biomarkers and therapeutic interventions.

Schisandra Inhibit Bleomycin-Induced Idiopathic Pulmonary Fibrosis in Rats via Suppressing M2 Macrophage Polarization

Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause and limited to the lungs. Schisandrae chinensis fructus (Wuweizi, Schisandra) is commonly used traditional Chinese medicines (TCM) for the treatment of pulmonary fibrosis, bronchitis, and other lung diseases in China. In this study, we investigated the therapeutic effect of Schisandra on IPF which is induced by bleomycin (BLM) in rats and the inhibition of alternatively activated macrophage (M2) polarization. Bleomycin-induced pulmonary fibrosis was used as a model for IPF, and rats were given drug interventions for 7 and 28 days to evaluate the role of Schisandra in the early oxidative phase and late fibrotic phases of BLM-induced pulmonary injury. The data showed that Schisandra exerted protective effects on BLM-induced pulmonary injury in two phases, which were improving inflammatory cell infiltration and severe damages of lung architectures and decreasing markers of M2 subtype. In order to prove the inhibitory effect of Schisandra on M2 polarization, in vitro experiments, we found that Schisandra downregulated the M2 ratio, which confirmed that the polarization of M2 was suppressed. Moreover, Schisandra blocked TGF-β1 signaling in AMs by reducing the levels of Smad3 and Smad4; meanwhile, the upregulation of Smad7 by Schisandra also promoted the effect of inhibition on the TGF-β1/Smad pathway. These results demonstrate that suppression of M2 polarization by Schisandra is associated with the development of IPF in rats.

CMH-Small Molecule Docks into SIRT1, Elicits Human IPF-Lung Fibroblast Cell Death, Inhibits Ku70-deacetylation, FLIP and Experimental Pulmonary Fibrosis

Regenerative capacity in vital organs is limited by fibrosis propensity. Idiopathic pulmonary fibrosis (IPF), a progressive lung disease linked with aging, is a classic example. In this study, we show that in flow cytometry, immunoblots (IB) and in lung sections, FLIP levels can be regulated, in vivo and in vitro, through SIRT1 activity inhibition by CMH (4-(4-Chloro-2-methylphenoxy)-N-hydroxybutanamide), a small molecule that, as we determined here by structural biology calculations, docked into its nonhistone substrate Ku70-binding site. Ku70 immunoprecipitations and immunoblots confirmed our theory that Ku70-deacetylation, Ku70/FLIP complex, myofibroblast resistance to apoptosis, cell survival, and lung fibrosis in bleomycin-treated mice, are reduced and regulated by CMH. Thus, small molecules associated with SIRT1-mediated regulation of Ku70 deacetylation, affecting FLIP stabilization in fibrotic-lung myofibroblasts, may be a useful strategy, enabling tissue regeneration.

Shedding light on developmental drugs for idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is an age-related disease of unknown cause. The disease is characterized by relentless scarring of the lung parenchyma resulting in respiratory failure and death. Two antifibrotic drugs (pirfenidone and nintedanib) are approved for the treatment of IPF worldwide, but they do not offer a cure and are associated with tolerability issues. Owing to its high unmet medical need, IPF is an area of dynamic research activity.

AREAS COVERED

There is a growing portfolio of novel therapies that target different pathways involved in the complex pathogenesis of IPF. In this review, we discuss the mechanisms of action and available data for compounds in the most advanced stages of clinical development. We searched PubMed for articles on this topic published from 1 January 2000, to 6 June 2020.

EXPERT OPINION

The approval of pirfenidone and nintedanib has fueled IPF drug discovery and development. New drugs are likely to reach the clinic in the near future. However, numerous challenges remain; the lack of animal models that reproduce the complexity of human disease and the poor translation of preclinical and early-phase positive effects to late stage clinical trials must be tackled.

Historical database cohort study addressing the clinical patterns prior to idiopathic pulmonary fibrosis (IPF) diagnosis in UK primary care

OBJECTIVE

To explore the clinical pathways, including signs and symptoms, and symptom progression patterns preceding idiopathic pulmonary fibrosis (IPF) diagnosis.

DESIGN AND SETTING

A historical cohort study was conducted using primary care patient records from the Optimum Patient Care Research Database.

PARTICIPANTS

Patients included were at least 30 years, had IPF diagnosis, identified via clinical-coding and free-text records and had a consultation with a chest specialist prior to IPF diagnosis.

OUTCOME MEASURES

The signs and symptoms in the year prior to IPF diagnosis from clinical codes and free-text in primary care electronic records included: cough, dyspnoea, dry cough, weight loss, fatigue/malaise, loss of appetite, crackles and clubbed fingers. The time course of presentations of clinical features and investigations in the years prior to IPF diagnosis were mapped.

RESULTS

Within 462 patients identified, the majority (77.9%) had a respiratory consultation within 365 days prior to the chest specialist visit preceding the IPF diagnosis recorded in their primary care records. The most common symptoms recorded in the 1 year prior to IPF diagnosis were dyspnoea (48.7%) and cough (40.9%); other signs and symptoms were rarely recorded (<5%). The majority of patients with cough (58.0%) and dyspnoea (55.0%) in the 1 year before IPF diagnosis had multiple recordings of the respective symptoms. Both cough and dyspnoea were recorded in 23.4% of patients in the year prior to diagnosis. Consultation rates for cough, dyspnoea and both, but not other signs or symptoms, began to increase 4 to 5 years prior diagnosis, with the sharpest increase in the last year. Cough and dyspnoea were often preceded by a reduction in measured weight over 5 years leading to IPF diagnosis.

CONCLUSION

Prolonged cough and/or progressive dyspnoea, especially if accompanied with weight loss, should signal for a referral to specialist assessment at the earliest opportunity.

IL-25/IL-33/TSLP contributes to idiopathic pulmonary fibrosis: Do alveolar epithelial cells and (myo)fibroblasts matter?

IMPACT STATEMENT

We suggest a novel modality in terms of IL-25/IL-33/TSLP's pro-fibrotic role in IPF. First, IL-25/IL-33/TSLP fully activates (myo)fibroblasts in fibroblastic foci (FF) in a paracrine-dependent manner. (IL-25/IL-33/TSLP)⁺alveolar epithelial cells-(IL-25R/IL-33R/TSLPR)⁺ (myo)fibroblasts axis may contribute greatly to the abnormal epithelial-mesenchymal crosstalk and lung fibrosis. Second, IL-25/IL-33/TSLP causes significant injury and phenotypic changes of alveolar epithelial cells in an autocrine-dependent manner. By acting directly on the two most important cells in the fibrotic process, i.e. alveolar epithelial cells and (myo)fibroblasts, we support the notion that biological therapies targeting IL-25/IL-33/TSLP will shed new light on the cure of IPF patients.

Highlights of high-resolution computed tomography imaging in evaluation of complications and co-morbidities in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) represents a condition included in the heterogeneous group of interstitial lung diseases without known causes. The recent ATS/ERS/JRS/ALAT guidelines and the white paper published by the Fleischner Society have well-defined diagnosis and management of idiopathic pulmonary fibrosis. Idiopathic pulmonary fibrosis management is complex because it is also influenced by several co-morbidities and complications. The new frontier in idiopathic pulmonary fibrosis is represented by the effort to understand the complex mechanism of the pathogenesis and progression of disease in order to predict several consequences and co-morbidities. In our review, we tried to distinguish co-morbidities from complications of idiopathic pulmonary fibrosis. In each complication, we have reviewed the existing literature and we have emphasized the complex pathobiological pathway which links the progression of idiopathic pulmonary fibrosis to the development of the complication itself. For every co-morbidity, we tried to identify share common risk factors which explain the coexistence of idiopathic pulmonary fibrosis with its co-morbidities. We then analyzed high-resolution computed tomography (CT) aspects of co-morbidities and complications of idiopathic pulmonary fibrosis that the radiologist should be aware of. In this review, we focused on the role of high-resolution CT imaging in the evaluation of co-morbidities and complications in idiopathic pulmonary fibrosis because their early diagnosis and treatment could change the prognosis in patients with idiopathic pulmonary fibrosis. We have also pointed out that in some cases the final combined quantitative CT tools and conventional visual CT score would allow to get an accurate analysis and quantification of disease progression, co-morbidities, and complications of idiopathic pulmonary fibrosis in order to improve staging systems in idiopathic pulmonary fibrosis.

Synthesis and discovery of new compounds bearing coumarin scaffold for the treatment of pulmonary fibrosis

Idiopathic pulmonary fibrosis, characterized by excess accumulation of extracellular matrix, involved in many chronic diseases or injuries, threatens human health greatly. We have reported a series of compounds bearing coumarin scaffold which potently inhibited TGF-β-induced total collagen accumulation in NRK-49F cell line and migration of macrophages. Compound 9d also suppressed the TGF-β-induced protein expression of COL1A1, α-SMA, and p-Smad3 in vitro. Meanwhile, 9d at a dose of 100 mg/kg/day through oral administrations for 4 weeks effectively alleviated infiltration of inflammatory cells in lung tissue and fibrotic degree in bleomycin-induced pulmonary fibrosis model, which may related to its inhibition of TGF-β/Smad3 pathway and anti-inflammation efficacy. In addition, 9d demonstrated decent bioavailability (F = 39.88%) and suitable eliminated half-life time (T_1/2 = 13.09 h), suggesting that 9d could be a potential drug candidate for the treatment of fibrotic diseases.

Effect of positron range on PET quantification in diseased and normal lungs

The impact of positron range on PET image reconstruction has often been investigated as a blurring effect that can be partly corrected by adding an element to the PET system matrix in the reconstruction, usually based on a Gaussian kernel constructed from the attenuation values. However, the physics involved in PET is more complex. In regions where density does not vary, positron range indeed involves mainly blurring. However, in more heterogeneous media it can cause other effects. This work focuses on positron range in the lungs and its impact on quantification, especially in the case of pathologies such as cancer or pulmonary fibrosis, for which the lungs have localised varying density. Using Monte Carlo simulations, we evaluate the effects of positron range for multiple radionuclides (¹⁸F, ¹⁵O, ⁶⁸Ga, ⁸⁹Zr, ⁸²Rb, ⁶⁴Cu and ¹²⁴I) as, for novel radiotracers, the choice of the labelling radionuclide is important. The results demonstrate quantification biases in highly heterogeneous media, where the measured uptake of high-density regions can be increased by the neighbouring radioactivity from regions of lower density, with the effect more noticeable for radionuclides with high-energy positron emission. When the low-density regions are considered to have less radioactive uptake (e.g. due to the presence of air), the effect is less severe.

Role of dual-specificity protein phosphatase DUSP10/MKP-5 in pulmonary fibrosis

Mitogen-activated protein kinase (MAPK) phosphatase 5 (MKP-5) is a member of the dual-specificity family of protein tyrosine phosphatases that negatively regulates p38 MAPK and the JNK. MKP-5-deficient mice exhibit improved muscle repair and reduced fibrosis in an animal model of muscular dystrophy. Here, we asked whether the effects of MKP-5 on muscle fibrosis extend to other tissues. Using a bleomycin-induced model of pulmonary fibrosis, we found that MKP-5-deficient mice were protected from the development of lung fibrosis, expressed reduced levels of hydroxyproline and fibrogenic genes, and displayed marked polarization towards an M1-macrophage phenotype. We showed that the profibrogenic effects of the transforming growth factor-β1 (TGF-β1) were inhibited in MKP-5-deficient lung fibroblasts. MKP-5-deficient fibroblasts exhibited enhanced p38 MAPK activity, impaired Smad3 phosphorylation, increased Smad7 levels, and decreased expression of fibrogenic genes. Myofibroblast differentiation was attenuated in MKP-5-deficient fibroblasts. Finally, we found that MKP-5 expression was increased in idiopathic pulmonary fibrosis (IPF)-derived lung fibroblasts but not in whole IPF lungs. These data suggest that MKP-5 plays an essential role in promoting lung fibrosis. Our results couple MKP-5 with the TGF-β1 signaling machinery and imply that MKP-5 inhibition may serve as a therapeutic target for human lung fibrosis.

Critical reappraisal of underlying histological patterns in patients with suspected idiopathic pulmonary fibrosis

PURPOSE OF REVIEW

Usual interstitial pneumonia (UIP) pattern is the histologic marker of idiopathic pulmonary fibrosis (IPF), but usefulness of ancillary histologic findings may discriminate idiopathic from secondary UIP.

RECENT FINDINGS

Alternative less invasive procedures may identify UIP pattern preventing conventional surgical lung biopsy, whereas genomic analysis may recognize UIP pattern from otherwise poorly diagnostic samples.

SUMMARY

High-resolution computed tomography identifies a 'definite' UIP pattern in about half of cases, failing to recognize UIP in the absence of honeycombing or in limited disease. Although radiologic criteria for UIP need redefinition to improve their diagnostic yield, histologic features of UIP did not significantly change from the 1960s but continue to represent a major diagnostic tool, particularly in challenging interstitial lung diseases. A careful recognition of some histologic ancillary findings in UIP (e.g., cellular/follicular bronchiolitis with germinal centers, chronic pleuritis, interstitial granulomas/giant cells, bridging fibrosis) may be helpful in supporting secondary forms (e.g., connective tissue disease, chronic hypersensitivity pneumonia) from IPF. Cryobiopsy and awake-biopsy are promising approaches to obtain representative lung tissue preventing conventional surgical lung biopsy. Genomic techniques have recently demonstrated good-to-high sensitivity and specificity to disclose UIP pattern starting from RNA obtained in transbronchial biopsy, possibly replacing and/or flanking soon traditional histology.

Apoptosis Resistance in Fibroblasts Precedes Progressive Scarring in Pulmonary Fibrosis and Is Partially Mediated by Toll-Like Receptor 4 Activation

Inhalation of environmental toxicants such as cigarette smoke, metal or wood dust, silica, or asbestos is associated with increased risk for idiopathic pulmonary fibrosis (IPF). IPF involves progressive scarring of lung tissue, which interferes with normal respiration and is ultimately fatal; however, the complex cellular mechanisms of IPF pathogenesis remain unclear. Fibroblast apoptosis is essential in normal wound healing but is dysregulated in IPF. Recent studies suggest that Toll-like receptor 4 (TLR4) is key in the onset of IPF. Here, radiation-induced PF was used as a model for IPF because it very closely mimics the progressive and intractable nature of IPF. Female C57BL/6J (C57) and C57BL/6J TLR4-/- mice were exposed to a single dose of 13 Gy whole-thorax ionizing radiation. Although both strains showed similar levels of immediate radiation-induced damage, C57 mice exhibited more extensive fibrosis at 22-week postirradiation (PI) than TLR4-/- mice. Isolated C57 primary 1° MLFs showed decreased apoptosis susceptibility as early as 8-week postirradiation, a phenotype that persisted for the remainder of the radiation response. TLR4-/- 1° mouse lung fibroblasts did not exhibit significant apoptosis resistance at any point. Systemic release of high mobility group box 1, a TLR4 agonist, during the pneumonitis phase of the radiation response may act through TLR4 to contribute to fibroblast apoptosis resistance and thus interfere with wound resolution. These findings demonstrate that apoptosis resistance occurs earlier in pulmonary fibrosis pathogenesis than previously assumed, and that TLR4 signaling is a key mediator in this process.