Matrix metalloproteinases as therapeutic targets for idiopathic pulmonary fibrosis

An Allysine-Conjugatable Probe for Fluorogenically Imaging Fibrosis

Allysine, a pivotal biomarker in fibrogenesis, has prompted the development of various radioactive imaging probes. However, fluorogenic probes targeting allysine remain largely unexplored. Herein, by leveraging the equilibrium between the nonfluorescent spirocyclic and the fluorescent zwitterionic forms of rhodamine-cyanine hybrid fluorophores, we systematically fine-tuned the environmental sensitivity of this equilibrium toward the development of fluorogenic probes for fibrosis. The trick lies in modulating the nucleophilicity of the ortho-carboxyl group, which is terminated with a hydrazide group for allysine conjugation. Probe B2 was developed with this strategy, which featured an N-sulfonyl amide group and exhibited superior fibrosis-to-control imaging contrast. Initially presenting as nonfluorescent spirocyclic aggregates in aqueous solutions, B2 displayed a notable fluorogenic response upon conjugation with protein allysine through its hydrazide group, inducing deaggregation and switching to the fluorescent zwitterionic form. Probe B2 outperformed the traditional Masson stain in imaging contrast, achieving an about 260-2600-fold ratio for fibrosis-to-control detection depending on fibrosis severity. Furthermore, it demonstrated efficacy in evaluating antifibrosis drugs. Our results emphasize the potential of this fluorogenic probe as an alternative to conventional fibrosis detection methods. It emerges as a valuable tool for antifibrosis drug evaluation.

Kefir peptides mitigate bleomycin-induced pulmonary fibrosis in mice through modulating oxidative stress, inflammation and gut microbiota

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and life-threatening lung disease with high mortality rates. The limited availability of effective drugs for IPF treatment, coupled with concerns regarding adverse effects and restricted responsiveness, underscores the need for alternative approaches. Kefir peptides (KPs) have demonstrated antioxidative, anti-inflammatory, and antifibrotic properties, along with the capability to modulate gut microbiota. This study aims to investigate the impact of KPs on bleomycin-induced pulmonary fibrosis.

METHODS

Mice were treated with KPs for four days, followed by intratracheal injection of bleomycin for 21 days. Comprehensive assessments included pulmonary functional tests, micro-computed tomography (µ-CT), in vivo image analysis using MMPsense750, evaluation of inflammation- and fibrosis-related gene expression in lung tissue, and histopathological examinations. Furthermore, a detailed investigation of the gut microbiota community was performed using full-length 16 S rRNA sequencing in control mice, bleomycin-induced fibrotic mice, and KPs-pretreated fibrotic mice.

RESULTS

In KPs-pretreated bleomycin-induced lung fibrotic mice, notable outcomes included the absence of significant bodyweight loss, enhanced pulmonary functions, restored lung tissue architecture, and diminished thickening of inter-alveolar septa, as elucidated by morphological and histopathological analyses. Concurrently, a reduction in the expression levels of oxidative biomarkers, inflammatory factors, and fibrotic indicators was observed. Moreover, 16 S rRNA sequencing demonstrated that KPs pretreatment induced alterations in the relative abundances of gut microbiota, notably affecting Barnesiella_intestinihominis, Kineothrix_alysoides, and Clostridium_viride.

CONCLUSIONS

Kefir peptides exerted preventive effects, protecting mice against bleomycin-induced lung oxidative stress, inflammation, and fibrosis. These effects are likely linked to modifications in the gut microbiota community. The findings highlight the therapeutic potential of KPs in mitigating pulmonary fibrosis and advocate for additional exploration in clinical settings.

L-arginine mitigates bleomycin-induced pulmonary fibrosis in rats through regulation of HO-1/PPAR-γ/β-catenin axis

Pulmonary fibrosis is a chronic and progressively deteriorating lung condition that can be replicated in laboratory animals by administering bleomycin, a chemotherapeutic antibiotic known for its lung fibrosis-inducing side effects. L-arginine, a semi-essential amino acid, is recognized for its diverse biological functions, including its potential to counteract fibrosis. This study aimed to evaluate the antifibrotic properties of L-arginine on bleomycin-induced pulmonary fibrosis in rats. The administration of a single intratracheal dose of bleomycin resulted in visible and microscopic damage to lung tissues, an uptick in oxidative stress markers, and an elevation in inflammatory, apoptotic, and fibrotic indicators. A seven-day treatment with L-arginine post-bleomycin exposure markedly improved the gross and histological architecture of the lungs, prevented the rise of malondialdehyde and carbonyl content, and enhanced total antioxidant capacity alongside the activities of antioxidant enzymes. Also, L-arginine attenuated the expression of the pro-fibrotic factors, transforming growth factor-β and lactate dehydrogenase in bronchoalveolar lavage fluid. In the lung tissue, L-arginine reduced collagen deposition, hydroxyproline concentration, and mucus production, along with decreasing expression of α-smooth muscle actin, tumor necrosis factor-α, caspase-3, matrix metalloproteinase-9, and β-catenin. Moreover, it boosted levels of nitric oxide and upregulated the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), heme oxygenase-1 (HO-1), and E-cadherin and downregulating the expression of β-catenin. These findings suggest that L-arginine has preventive activities against bleomycin-induced pulmonary fibrosis. This effect can be attributed to the increased production of nitric oxide, which modulates the HO-1/PPAR-γ/β-catenin axis.

Identification and validation of mutual hub genes in idiopathic pulmonary fibrosis and rheumatoid arthritis-associated usual interstitial pneumonia

Objectives

The study aims at exploring common hub genes and pathways in idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis-associated usual interstitial pneumonia (RA-UIP) through integrated bioinformatics analyses.

Methods

The GSE199152 dataset containing lung tissue samples from IPF and RA-UIP patients was acquired from the Gene Expression Omnibus (GEO) database. The identification of overlapping differentially expressed genes (DEGs) in IPF and RA-UIP was carried out through R language. Protein-protein interaction (PPI) network analysis and module analysis were applied to filter mutual hub genes in the two diseases. Enrichment analyses were also conducted to analyze the possible biological functions and pathways of the overlapped DEGs and hub genes. The diagnostic value of key genes was assessed with R language, and the expressions of these genes in pulmonary cells of IPF and rheumatoid arthritis-associated interstitial lung disease (RA-ILD) patients were analyzed with single cell RNA-sequencing (scRNA-seq) datasets. The expression levels of hub genes were validated in blood samples from patients, specimens of human lung fibroblasts, lung tissue samples from mice, as well as external GEO datasets.

Results

Four common hub genes (THBS2, TIMP1, POSTN, and CD19) were screened. Enrichment analyses showed that the abnormal expressions of DEGs and hub genes may be connected with the onset of IPF and RA-UIP by regulating the progression of fibrosis. ScRNA-seq analyses illustrated that for both IPF and RA-ILD patients, THBS2, TIMP1, and POSTN were mainly expressed in lung fibroblasts, while CD19 was uniquely high-expressed in B cells. The qRT-PCR and immunohistochemistry (IHC) results verified that the expression levels of hub genes were mostly in accordance with the findings obtained from the bioinformatics analyses.

Conclusion

Though IPF and RA-UIP are distinct diseases, they may to some extent have mutual pathogenesis in the development of fibrosis. THBS2, TIMP1, POSTN, and CD19 may be the potential biomarkers of IPF and RA-UIP, and intervention on related pathways of these genes could offer new strategies for the precision treatment of IPF and RA-UIP.

ALKBH5 SUMOylation-mediated FBXW7 m6A modification regulates alveolar cells senescence during 1-nitropyrene-induced pulmonary fibrosis

Our previous study revealed that 1-nitropyrene (1-NP) exposure evoked pulmonary fibrosis in mice. However, the exact mechanism remained elusive. We found that 1-NP induced telomere damage and cellular senescence in mice lungs, and two alveolar epithelial cells lines. 1-NP downregulated telomere repeat binding factor 2 (TRF2), and upregulated FBXW7. Mechanistically, 1-NP-caused TRF2 ubiquitination and proteasomal degradation depended on E3 ubiquitin ligase activity of FBXW7. Moreover, 1-NP upregulated FBXW7 m6A modification via an ALKBH5-YTHDF1-dependent manner. Further analysis suggested 1-NP promoted ALKBH5 SUMOylation and subsequent proteasomal degradation. Additionally, 1-NP evoked mitochondrial reactive oxygen species (mtROS) overproduction. Mito-TEMPO, a mitochondrial-targeted antioxidant, mitigated 1-NP-caused mtROS overproduction, ALKBH5 SUMOylation, FBXW7 m6A modification, TRF2 degradation, cellular senescence, and pulmonary fibrosis. Taken together, mtROS-initiated ALKBH5 SUMOylation and subsequent FBXW7 m6A modification is indispensable for TRF2 degradation and cellular senescence in alveolar epithelial cells during 1-NP-induced pulmonary fibrosis. Our study provides target intervention measures towards 1-NP-evoked pulmonary fibrosis.

Exploring therapeutic targets for molecular therapy of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a chronic and progressive interstitial lung disease with a poor prognosis. Idiopathic pulmonary fibrosis is characterized by repeated alveolar epithelial damage leading to abnormal repair. The intercellular microenvironment is disturbed, leading to continuous activation of fibroblasts and myofibroblasts, deposition of extracellular matrix, and ultimately fibrosis. Moreover, pulmonary fibrosis was also found as a COVID-19 complication. Currently, two drugs, pirfenidone and nintedanib, are approved for clinical therapy worldwide. However, they can merely slow the disease's progression rather than rescue it. These two drugs have other limitations, such as lack of efficacy, adverse effects, and poor pharmacokinetics. Consequently, a growing number of molecular therapies have been actively developed. Treatment options for IPF are becoming increasingly available. This article reviews the research platform, including cell and animal models involved in molecular therapy studies of idiopathic pulmonary fibrosis as well as the promising therapeutic targets and their development progress during clinical trials. The former includes patient case/control studies, cell models, and animal models. The latter includes transforming growth factor-beta, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, lysophosphatidic acid, interleukin-13, Rho-associated coiled-coil forming protein kinase family, and Janus kinases/signal transducers and activators of transcription pathway. We mainly focused on the therapeutic targets that have not only entered clinical trials but were publicly published with their clinical outcomes. Moreover, this work provides an outlook on some promising targets for further validation of their possibilities to cure the disease.

HTRA1-driven detachment of type I collagen from endoplasmic reticulum contributes to myocardial fibrosis in dilated cardiomyopathy

BACKGROUND

The aberrant secretion and excessive deposition of type I collagen (Col1) are important factors in the pathogenesis of myocardial fibrosis in dilated cardiomyopathy (DCM). However, the precise molecular mechanisms underlying the synthesis and secretion of Col1 remain unclear.

METHODS AND RESULTS

RNA-sequencing analysis revealed an increased HtrA serine peptidase 1 (HTRA1) expression in patients with DCM, which is strongly correlated with myocardial fibrosis. Consistent findings were observed in both human and mouse tissues by immunoblotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunohistochemistry, and immunofluorescence analyses. Pearson's analysis showed a markedly positive correlation between HTRA1 level and myocardial fibrosis indicators, including extracellular volume fraction (ECV), native T1, and late gadolinium enhancement (LGE), in patients with DCM. In vitro experiments showed that the suppression of HTRA1 inhibited the conversion of cardiac fibroblasts into myofibroblasts and decreased Col1 secretion. Further investigations identified the role of HTRA1 in promoting the formation of endoplasmic reticulum (ER) exit sites, which facilitated the transportation of Col1 from the ER to the Golgi apparatus, thereby increasing its secretion. Conversely, HTRA1 knockdown impeded the retention of Col1 in the ER, triggering ER stress and subsequent induction of ER autophagy to degrade misfolded Col1 and maintain ER homeostasis. In vivo experiments using adeno-associated virus-serotype 9-shHTRA1-green fluorescent protein (AAV9-shHTRA1-GFP) showed that HTRA1 knockdown effectively suppressed myocardial fibrosis and improved left ventricular function in mice with DCM.

CONCLUSIONS

The findings of this study provide valuable insights regarding the treatment of DCM-associated myocardial fibrosis and highlight the therapeutic potential of targeting HTRA1-mediated collagen secretion.

Pulmonary Fibrosis and Diabetes Mellitus: Two coins with the same face

Idiopathic pulmonary fibrosis (IPF) constitutes a long-term disease with a complex pathophysiology composed of multiple molecular actors that lead to the deposition of extracellular matrix, the loss of pulmonary function and ultimately the patient's death. Despite the approval of pirfenidone and nintedanib for the treatment of the disease, lung transplant is the only long-term solution to fully recover the respiratory capacity and gain quality of life. One of the risk factors for the development of IPF is the pre-existing condition of diabetes mellitus. Both, IPF and diabetes mellitus, share similar pathological damage mechanisms, including inflammation, endoplasmic reticulum stress, mitochondrial failure, oxidative stress, senescence and signaling from glycated proteins through receptors. In this critical review article, we provide information about this interrelationship, examining molecular mediators that play an essential role in both diseases and identify targets of interest for the development of potential drugs. We review the findings of clinical trials examining the progression of IPF and how novel molecules may be used to stop this process. The results highlight the importance of early detection and addressing multiple therapeutic targets simultaneously to achieve better therapeutic efficacy and potentially reverse lung fibrosis.

The role of macrophage polarization and cellular crosstalk in the pulmonary fibrotic microenvironment: a review

Pulmonary fibrosis (PF) is a progressive interstitial inflammatory disease with a high mortality rate. Patients with PF commonly experience a chronic dry cough and progressive dyspnoea for years without effective mitigation. The pathogenesis of PF is believed to be associated with dysfunctional macrophage polarization, fibroblast proliferation, and the loss of epithelial cells. Thus, it is of great importance and necessity to explore the interactions among macrophages, fibroblasts, and alveolar epithelial cells in lung fibrosis, as well as in the pro-fibrotic microenvironment. In this review, we discuss the latest studies that have investigated macrophage polarization and activation of non-immune cells in the context of PF pathogenesis and progression. Next, we discuss how profibrotic cellular crosstalk is promoted in the PF microenvironment by multiple cytokines, chemokines, and signalling pathways. And finally, we discuss the potential mechanisms of fibrogenesis development and efficient therapeutic strategies for the disease. Herein, we provide a comprehensive summary of the vital role of macrophage polarization in PF and its profibrotic crosstalk with fibroblasts and alveolar epithelial cells and suggest potential treatment strategies to target their cellular communication in the microenvironment.

The TIMP protein family: diverse roles in pathophysiology

The tissue inhibitors of matrix metalloproteinases (TIMPs) are a family of four matrisome proteins classically defined by their roles as the primary endogenous inhibitors of metalloproteinases (MPs). Their functions however are not limited to MP inhibition, with each family member harboring numerous MP-independent biological functions that play key roles in processes such as inflammation and apoptosis. Because of these multifaceted functions, TIMPs have been cited in diverse pathophysiological contexts. Herein, we provide a comprehensive overview of the MP-dependent and -independent roles of TIMPs across a range of pathological conditions. The potential therapeutic and biomarker applications of TIMPs in these disease contexts are also considered, highlighting the biomedical promise of this complex and often misunderstood protein family.

Mechanical forces amplify TCR mechanotransduction in T cell activation and function

Adoptive T cell immunotherapies, including engineered T cell receptor (eTCR) and chimeric antigen receptor (CAR) T cell immunotherapies, have shown efficacy in treating a subset of hematologic malignancies, exhibit promise in solid tumors, and have many other potential applications, such as in fibrosis, autoimmunity, and regenerative medicine. While immunoengineering has focused on designing biomaterials to present biochemical cues to manipulate T cells ex vivo and in vivo, mechanical cues that regulate their biology have been largely underappreciated. This review highlights the contributions of mechanical force to several receptor-ligand interactions critical to T cell function, with central focus on the TCR-peptide-loaded major histocompatibility complex (pMHC). We then emphasize the role of mechanical forces in (i) allosteric strengthening of the TCR-pMHC interaction in amplifying ligand discrimination during T cell antigen recognition prior to activation and (ii) T cell interactions with the extracellular matrix. We then describe approaches to design eTCRs, CARs, and biomaterials to exploit TCR mechanosensitivity in order to potentiate T cell manufacturing and function in adoptive T cell immunotherapy.

Novel therapeutic targets, including IGFBP3, of umbilical cord mesenchymal stem-cell-conditioned medium in intrauterine adhesion

Mesenchymal stem cells play important roles in repairing injured endometrium. However, the molecular targets and potential mechanism of the endometrial recipient cells for stem cell therapy in intrauterine adhesion (IUA) are poorly understood. In this study, umbilical cord mesenchymal stem-cell-conditioned medium (UCMSCs-CM) produced positive effects on a Transforming growth factor beta (TGF-β) induced IUA cell model. RNA-sequencing was performed on clinical IUA tissues, and the top 40 upregulated and top 20 downregulated mRNAs were selected and verified using high-throughput (HT) qPCR in both tissues and cell models. Based on a bioinformatic analysis of RNA-sequencing and HT-qPCR results, 11 mRNAs were uncovered to be the intervention targets of UCMSCs-CM on IUA endometrium cell models. Among them, IGFBP3 was striking as a key pathogenic gene and a potential diagnostic marker of IUA, which exhibited the area under the curve (AUC), sensitivity, specificity were 0.924, 93.1% and 80.6%, respectively in 60 endometrial tissues. The silencing of IGFBP3 exerted positive effects on the IUA cell model through partially upregulating MMP1 and KLF2. In conclusion, RNA-sequencing combined with HT qPCR based on clinical tissues and IUA cell models were used in IUA research and our results may provide some scientific ideas for the diagnosis and treatment of IUA.

Advances in the research and application of neurokinin-1 receptor antagonists

Recently, the substance P (SP)/neurokinin-1 receptor (NK-1R) system has been found to be involved in various human pathophysiological disorders including the symptoms of coronavirus disease 2019 (COVID-19). Besides, studies in the oncological field have demonstrated an intricate correlation between the upregulation of NK-1R and the activation of SP/NK-1R system with the progression of multiple carcinoma types and poor clinical prognosis. These findings indicate that the modulation of SP/NK-1R system with NK-1R antagonists can be a potential broad-spectrum antitumor strategy. This review updates the latest potential and applications of NK-1R antagonists in the treatment of human diseases and cancers, as well as the underlying mechanisms. Furthermore, the strategies to improve the bioavailability and efficacy of NK-1R antagonist drugs are summarized, such as solid dispersion systems, nanonization, and nanoencapsulation. As a radiopharmaceutical therapeutic, the NK-1R antagonist aprepitant was originally developed as radioligand receptor to target NK-1R-overexpressing tumors. However, combining NK-1R antagonists with other drugs can produce a synergistic effect, thereby enhancing the therapeutic effect, alleviating the symptoms, and improving patients quality of life in several diseases and cancers.

Deciphering the fibrotic process: mechanism of chronic radiation skin injury fibrosis

This review explores the mechanisms of chronic radiation-induced skin injury fibrosis, focusing on the transition from acute radiation damage to a chronic fibrotic state. It reviewed the cellular and molecular responses of the skin to radiation, highlighting the role of myofibroblasts and the significant impact of Transforming Growth Factor-beta (TGF-β) in promoting fibroblast-to-myofibroblast transformation. The review delves into the epigenetic regulation of fibrotic gene expression, the contribution of extracellular matrix proteins to the fibrotic microenvironment, and the regulation of the immune system in the context of fibrosis. Additionally, it discusses the potential of biomaterials and artificial intelligence in medical research to advance the understanding and treatment of radiation-induced skin fibrosis, suggesting future directions involving bioinformatics and personalized therapeutic strategies to enhance patient quality of life.

Efficient pulmonary fibrosis therapy via regulating macrophage polarization using respirable cryptotanshinone-loaded liposomal microparticles

Lung inflammation and fibrogenesis are the two main characteristics during the development of pulmonary fibrosis (PF), which are particularly associated with pulmonary macrophages. In this context, whether cryptotanshinone (CTS) could alleviate PF through regulating macrophage polarization were preliminarily demonstrated in vitro. Then the time course of PF and its relationship with macrophage polarization was determined in BLM-induced mice based on cytokine levels in bronchoalveolar lavage fluid (BALF), lung histopathology, flow cytometric analysis, mRNA and protein expression. CTS was loaded into macrophage-targeted and responsively released mannose-modified liposomes (Man-lipo), and the liposomes were then embedded into mannitol microparticles (M-MPs) using spray drying to achieve efficient pulmonary delivery. Afterwards, how CTS regulates macrophage polarization in vivo during different time courses of PF was probed. Furthermore, the molecular mechanisms of CTS against PF by regulating macrophage polarization were elucidated in vivo and in vitro. The full-course therapy group could achieve comparable therapeutic effects compared with the positive control drug PFD group. CTS can alleviate PF through regulating macrophage polarization, mainly by inhibiting NLRP3/TGF-β1 pathway during the inflammation course and modulating MMP-9/TIMP-1 balance during the fibrosis development course, providing new insights into chronic PF treatment.

Exhaled nitric oxide is associated with inflammatory biomarkers and risk of acute respiratory exacerbations in children with HIV-associated chronic lung disease

OBJECTIVES

Chronic lung disease is a recognized complication in children with HIV. Acute respiratory exacerbations (ARE) are common among this group and cause significant morbidity. Exhaled nitric oxide (eNO) is a known marker of local airway inflammation. We investigated the association between eNO and ARE, biomarkers of systemic inflammation, and the effect of azithromycin on eNO levels.

METHODS

Individuals aged 6-19 years with HIV-associated chronic lung disease in Harare, Zimbabwe, were enrolled in a placebo-controlled randomized trial investigating the effect of 48-week azithromycin treatment on lung function and ARE. eNO levels and biomarkers were measured at inclusion and after treatment in a consecutively enrolled subset of participants. Linear regression and generalized linear models were used to study associations between eNO and ARE, biomarkers, and the effect of azithromycin on eNO levels.

RESULTS

In total, 172 participants were included in this sub-study, 86 from the placebo group and 86 from the azithromycin group. Participants experiencing at least one ARE during follow-up had significantly higher eNO levels at baseline than participants who did not (geometric mean ratio 1.13, 95% confidence interval [CI] 1.03-1.24, p = 0.015), adjusted for trial arm, age, sex and history of tuberculosis. Matrix metalloproteinase (MMP)-3, -7, and -10 were significantly associated with higher baseline eNO levels. At 48 weeks, azithromycin treatment did not affect eNO levels (geometric mean ratio 0.86, 95% CI 0.72-1.03, p = 0.103).

CONCLUSION

Higher baseline eNO levels were a risk factor for ARE. eNO was associated with proinflammatory biomarkers previously found to contribute to the development of chronic lung disease. The potential use of eNO as a marker of inflammation and risk factor for ARE in HIV-associated chronic lung disease needs further investigation.

MMP14high macrophages orchestrate progressive pulmonary fibrosis in SR-Ag-induced hypersensitivity pneumonitis

Fibrotic hypersensitivity pneumonitis (FHP) is a fatal interstitial pulmonary disease with limited treatment options. Lung macrophages are a heterogeneous cell population that exhibit distinct subsets with divergent functions, playing pivotal roles in the progression of pulmonary fibrosis. However, the specific macrophage subpopulations and underlying mechanisms involved in the disease remain largely unexplored. In this study, a decision tree model showed that matrix metalloproteinase-14 (MMP14) had higher scores for important features in the up-regulated genes in macrophages from mice exposed to the Saccharopolyspora rectivirgula antigen (SR-Ag). Using single-cell RNA sequencing (scRNA-seq) analysis of hypersensitivity pneumonitis (HP) mice profiles, we identified MMP14high macrophage subcluster with a predominant M2 phenotype that exhibited higher activity in promoting fibroblast-to myofibroblast transition (FMT). We demonstrated that suppressing toll-like receptor 2 (TLR2) and nuclear factor kappa-B (NF-κB) could attenuate MMP14 expression and exosome secretion in macrophages stimulation with SR-Ag. The exosomes derived from MMP14-overexpressing macrophages were found to be more effective in regulating the transition of fibroblasts through exosomal MMP14. Importantly, it was observed that the transfer of MMP14-overexpressing macrophages into mice promoted lung inflammation and fibrosis induced by SR-Ag. NSC-405020 binding to the hemopexin domain (PEX) of MMP-14 ameliorated lung inflammation and fibrosis induced by SR-Ag in mice. Thus, MMP14-overexpressing macrophages may be an important mechanism contributing to the exacerbation of allergic reactions. Our results indicated that MMP14 in macrophages has the potential to be a therapeutic target for HP.

Worldwide productivity and research trend of publications concerning extracellular vesicles role in fibrosis: A bibliometric study from 2013 to 2022

Background

Fibrosis is a heavy burden on the global healthcare system. Recently, an increasing number of studies have demonstrated that Extracellular vesicles play an important role in intercellular communication under both physiological and pathological conditions. This study aimed to explore the role of extracellular vesicles' in fibrosis using bibliometric methods.

Methods

Original articles and reviews related to extracellular vesicles and fibrosis were obtained from the Web of Science Core Collection database on November 9, 2022. VOSviewer was used to obtain general information, including co-institution, co-authorship, and co-occurrence visualization maps. The CiteSpace software was used to analyze citation bursts of keywords and references, a timeline view of the top clusters of keywords and cited articles, and the dual map. R package "bibliometrix" was used to analyze annual production, citation per year, collaboration network between countries/regions, thematic evolution map, and historiography network.

Results

In total, 3376 articles related to extracellular vesicles and fibrosis published from 2013 to 2022 were included in this study, with China and the United States being the top contributors. Shanghai Jiao Tong University has the highest number of publications. The main collaborators were Giovanni Camussi, Stefania Bruno, Marta Tepparo, and Cristina Grange. Journals related to molecular, biology, genetics, health, immunology, and medicine tended to publish literature on extracellular vesicles and fibrosis. "Recovery," "heterogeneity," "degradation," "inflammation," and "mesenchymal stem cells" are the keywords in this research field. Literature on extracellular vesicles and fibrosis associated with several diseases, including "kidney disease," "rheumatoid arthritis," and "skin regeneration" may be the latest hot research field.

Conclusions

This study provides a comprehensive perspective on extracellular vesicles and fibrosis through a bibliometric analysis of articles published between 2013 and 2022. We identified the most influential countries, institutions, authors, and journals. We provide information on recent research frontiers and trends for scholars interested in the field of extracellular vesicles and fibrosis. Their role in biological processes has great potential to initiate a new upsurge in future research.

Predictive biomarkers of disease progression in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial disease that cannot be cured, and treatment options for IPF are very limited. Early diagnosis, close monitoring of disease progression, and timely treatment are therefore the best options for patients due to the irreversibility of IPF. Effective markers help doctors judge the development and prognosis of disease. Recent research on traditional biomarkers (KL-6, SP-D, MMP-7, TIMPs, CCL18) has provided novel ideas for predicting disease progression and prognosis. Some emerging biomarkers (HE4, GDF15, PRDX4, inflammatory cells, G-CSF) also provide more possibilities for disease prediction. In addition to markers in serum and bronchoalveolar lavage fluid (BALF), some improvements related to the GAP model and chest HRCT also show good predictive ability for disease prognosis.

Pyroptosis-related signatures predict immune characteristics and prognosis in IPF

The purpose of this work was to use integrated bioinformatics analysis to screen for pyroptosis-related genes (PRGs) and possible immunological phenotypes linked to the development and course of IPF. Transcriptome sequencing datasets GSE70866, GSE47460 and GSE150910 were obtained from GEO database. From the GSE70866 database, 34 PRGs with differential expression were found in IPF as compared to healthy controls. In addition, a diagnostic model containing 4 genes PRGs (CAMP, MKI67, TCEA3 and USP24) was constructed based on LASSO logistic regression. The diagnostic model showed good predictive ability to differentiate between IPF and healthy, with ROC-AUC ranging from 0.910 to 0.997 in GSE70866 and GSE150910 datasets. Moreover, based on a combined cohort of the Freiburg and the Siena cohorts from GSE70866 dataset, we identified ten PRGs that might predict prognosis for IPF. We constructed a prognostic model that included eight PRGs (CLEC5A, TREM2, MMP1, IRF2, SEZ6L2, ADORA3, NOS2, USP24) by LASSO Cox regression and validated it in the Leuven cohort. The risk model divided IPF patients from the combined cohort into high-risk and low-risk subgroups. There were significant differences between the two subgroups in terms of IPF survival and GAP stage. There is a close correlation between leukocyte migration, plasma membrane junction, and poor prognosis in a high-risk subgroup. Furthermore, a high-risk score was associated with more plasma cells, activated NK cells, monocytes, and activated mast cells. Additionally, we identified HDAC inhibitors in the cMAP database that might be therapeutic for IPF. To summarize, pyroptosis and its underlying immunological features are to blame for the onset and progression of IPF. PRG-based predictive models and drugs may offer new treatment options for IPF.

Unraveling the mechanism of ethyl acetate extract from Prismatomeris connata Y. Z. Ruan root in treating pulmonary fibrosis: insights from bioinformatics, network pharmacology, and experimental validation

Introduction

Pulmonary fibrosis is a terminal lung disease characterized by fibroblast proliferation, extracellular matrix accumulation, inflammatory damage, and tissue structure destruction. The pathogenesis of this disease, particularly idiopathic pulmonary fibrosis (IPF), remains unknown. Macrophages play major roles in organ fibrosis diseases, including pulmonary fibrosis. The phenotype and polarization of macrophages are closely associated with pulmonary fibrosis. A new direction in research on anti-pulmonary fibrosis is focused on developing drugs that maintain the stability of the pulmonary microenvironment.

Methods

We obtained gene sequencing data and clinical information for patients with IPF from the GEO datasets GSE110147, GSE15197, GSE24988, GSE31934, GSE32537, GSE35145, GSE53845, GSE49072, GSE70864, and GSE90010. We performed GO, KEGG enrichment analysis and GSEA analysis, and conducted weighted gene co-expression network analysis. In addition, we performed proteomic analysis of mouse lung tissue. To verify the results of bioinformatics analysis and proteomic analysis, mice were induced by intratracheal instillation of bleomycin (BLM), and gavaged for 14 days after modeling. Respiratory function of mice in different groups was measured. Lung tissues were retained for histopathological examination, Western Blot and real-time quantitative PCR, etc. In addition, lipopolysaccharide, interferon-γ and interleukin-4 were used to induce RAW264.7 cells for 12h in vitro to establish macrophage inflammation and polarization model. At the same time, HG2 intervention was given. The phenotype transformation and cytokine secretion of macrophages were investigated by Western Blot, RT-qPCR and flow cytometry, etc.

Results

Through bioinformatics analysis and experiments involving bleomycin-induced pulmonary fibrosis in mice, we confirmed the importance of macrophage polarization in IPF. The analysis revealed that macrophage polarization in IPF involves a change in the phenotypic spectrum. Furthermore, experiments demonstrated high expression of M2-type macrophage-associated biomarkers and inducible nitric oxide synthase, thus indicating an imbalance in M1/M2 polarization of pulmonary macrophages in mice with pulmonary fibrosis.

Discussion

Our investigation revealed that the ethyl acetate extract (HG2) obtained from the roots of Prismatomeris connata Y. Z. Ruan exhibits therapeutic efficacy against bleomycin-induced pulmonary fibrosis. HG2 modulates macrophage polarization, alterations in the TGF-β/Smad pathway, and downstream protein expression in the context of pulmonary fibrosis. On the basis of our findings, we believe that HG2 has potential as a novel traditional Chinese medicine component for treating pulmonary fibrosis.

Macrophage-derived MMP12 promotes fibrosis through sustained damage to endothelial cells

Macrophages are essential for the maintenance of endothelial cell function. However, the potential impact and mechanisms of crosstalk between macrophages and endothelial cells during silicosis progression remain unexplored. To fill this knowledge gap, a mouse model of silicosis was established. Single cell sequencing, spatial transcriptome sequencing, western blotting, immunofluorescence staining, tube-forming and wound healing assays were used to explore the effects of silicon dioxide on macrophage-endothelial interactions. To investigate the mechanism of macrophage-mediated fibrosis, MMP12 was specifically inactivated using siRNA and pharmacological approaches, and macrophages were depleted using disodium chlorophosphite liposomes. Compared to the normal saline group, the silica dust group showed altered macrophage-endothelial interactions. Matrix metalloproteinase family member MMP12 was identified as a key mediator of the altered function of macrophage-endothelial interactions after silica exposure, which was accompanied by pro-inflammatory macrophage activation and fibrotic progression. By using ablation strategies, macrophage-derived MMP12 was shown to mediate endothelial cell dysfunction by accumulating on the extracellular matrix. During the inflammatory phase of silicosis, MMP12 secreted by pro-inflammatory macrophages caused decreased endothelial cell viability, reduced migration, decreased trans-endothelial resistance and increased permeability; while during the fibrotic phase, macrophage-derived MMP12 sustained endothelial cell injury through accumulation on the extracellular matrix.

Human apical-out nasal organoids reveal an essential role of matrix metalloproteinases in airway epithelial differentiation

Extracellular matrix (ECM) assembly/disassembly is a critical regulator for airway epithelial development and remodeling. Airway organoid is widely used in respiratory research, yet there is limited study to indicate the roles and mechanisms of ECM organization in epithelial growth and differentiation by using in vitro organoid system. Moreover, most of current Matrigel-based airway organoids are in basal-out orientation where accessing the apical surface is challenging. We present a human apical-out airway organoid using a biochemically defined hybrid hydrogel system. During human nasal epithelial progenitor cells (hNEPCs) differentiation, the gel gradually degrade, leading to the organoid apical surfaces facing outward. The expression and activity of ECM-degrading enzymes, matrix metalloproteinases (MMP7, MMP9, MMP10 and MMP13) increases during organoid differentiation, where inhibition of MMPs significantly suppresses the normal ciliation, resulting in increased goblet cell proportion. Moreover, a decrease of MMPs is found in goblet cell hyperplastic epithelium in inflammatory mucosa. This system reveals essential roles of epithelial-derived MMPs on epithelial cell fate determination, and provides an applicable platform enabling further study for ECM in regulating airway development in health and diseases.

Associations of MMP9 polymorphism with the risk of severe pneumonia in a Southern Chinese children population

BACKGROUND

Severe pneumonia frequently causes irreversible sequelae and represents a major health burden for children under the age of 5. Matrix Metallopeptidase 9 (MMP9) is a zinc-dependent endopeptidase that is involved in various cellular processes. The correlation between MMP9 and the risk of severe childhood pneumonia remains unclear.

METHODS

Here we assemble a case-control cohort to study the association of genetic variants in MMP9 gene with severe childhood pneumonia susceptibility in a Southern Chinese population (1034 cases and 8426 controls).

RESULTS

Our results indicate that the allele G in rs3918262 SNP was significantly associated with an increased risk of severe pneumonia. Bioinformatic analyses by expression quantitative trait loci (eQTL), RegulomeDB and FORGEdb database analysis showed that rs3918262 SNP has potential regulatory effect on translational efficiency and protein level of MMP9 gene. Furthermore, MMP9 concentrations were significantly up-regulated in the bronchoalveolar lavages (BALs) of children with severe pneumonia.

CONCLUSION

In summary, our findings suggest that MMP9 is a novel predisposing gene for childhood pneumonia.

Strain inhibition of bacterial collagenase is consistent with a collagen fibril uncrimping mechanism in rat tail tendons

Mechanical strain inhibits bacterial collagenase from cleaving collagen. Additionally, the toe region of a soft tissue's force-elongation curve arises from sequentially engaging collagen fibrils as the tissue lengthens. Together, these phenomena suggest that mechanical strain may gradually inhibit collagenase activity through a soft tissue's toe region. Therefore, this investigation sought to test this hypothesis. 92 rat tail tendon fascicles from 3 female sentinel animals underwent preliminary stiffness tests, and their force-elongation curves were fit to a collagen distribution model. This distribution-based model calculated the force magnitude corresponding to p% of collagen fibril engagement. Specimens were separated into one of five levels of p, and that level of force was maintained for two hours while being exposed to 0.054 U/mL of bacterial collagenase from C. histolyticum. The specimens were strained to failure following the creep test, and the relative reduction in stiffness was quantified to estimate the fraction of digested fibrils. Every 10% additional collagen engagement corresponded to a 6.3% (97% highest density interval: 4.3 - 8.4%) retention of stiffness, which indicated collagenase inhibition. The results of this investigation were consistent with a strain-inhibition hypothesis along with the established uncrimping mechanism in the toe region. These results support an interaction between mechanical strain and collagenolysis, which may be valuable for disease prevention or treatment.

Expression and Purification of Active Monomeric MMP7

MMP7 is the smallest member of the MMP family and plays multiple physiological and pathological roles through interaction with a variety of molecules. Purified MMP7 would be beneficial for studying its function and for the development of inhibitors, which could be potential therapeutics. Due to low levels of endogenously produced MMP7, its recombinant expression and purification using E. coli have been established. Here, we describe an effective method to express and purify an active form of MMP7. Our recent discovery is that adding high concentration of CaCl2 during refolding process prevents nonspecific binding of MMP7 to plastic and its aggregation, significantly improving the yield of active monomeric forms of MMP7.

Temporal analysis of lung injury induced by real-ambient PM2 .5 exposure in mice

Fine particulate matter (PM2.5 ) has been shown to induce lung injury. However, the pathophysiological mechanisms of PM2.5 -induced pulmonary injury after different exposure times are poorly understood. In this study, we exposed male ICR mice to a whole-body PM2.5 inhalation system at daily mean concentration range from 92.00 to 862.00 μg/m3 for 30, 60, and 90 days. We found that following prolonged exposure to PM2.5 , pulmonary injury was increasingly evident with significant histopathological alterations. Notably, the pulmonary inflammatory response and fibrosis caused by PM2.5 after different exposure times were closely associated with histopathological changes. In addition, PM2.5 exposure caused oxidative stress, DNA damage and impairment of DNA repair in a time-dependent manner in the lung. Importantly, exposure to PM2.5 eventually caused apoptosis in the lung through upregulation of cleaved-caspase-3 and downregulation of Bcl-2. Overall, our data demonstrated that PM2.5 led to pulmonary injury in a time-dependent manner via upregulation of proinflammatory and fibrosis-related genes, and activation of the DNA damage response. Our findings provided a novel perspective on the pathophysiology of respiratory diseases caused by airborne pollution.

Toosendanin Restrains Idiopathic Pulmonary Fibrosis by Inhibiting ZEB1/CTBP1 Interaction

BACKGROUND

Extensive deposition of extracellular matrix (ECM) in idiopathic pulmonary fibrosis (IPF) is due to hyperactivation and proliferation of pulmonary fibroblasts. However, the exact mechanism is not clear.

OBJECTIVE

This study focused on the role of CTBP1 in lung fibroblast function, elaborated its regulation mechanism, and analyzed the relationship between CTBP1 and ZEB1. Meanwhile, the antipulmonary fibrosis effect and its molecular mechanism of Toosendanin were studied.

METHODS

Human IPF fibroblast cell lines (LL-97A and LL-29) and normal fibroblast cell lines (LL-24) were cultured in vitro. The cells were stimulated with FCS, PDGF-BB, IGF-1, and TGF-β1, respectively. BrdU detected cell proliferation. The mRNA expression of CTBP1 and ZEB1 was detected by QRT-PCR. Western blotting was used to detect the expression of COL1A1, COL3A1, LN, FN, and α-SMA proteins. An animal model of pulmonary fibrosis was established to analyze the effects of CTBP1 silencing on pulmonary fibrosis and lung function in mice.

RESULTS

CTBP1 was up-regulated in IPF lung fibroblasts. Silencing CTBP1 inhibits growth factor-driven proliferation and activation of lung fibroblasts. Overexpression of CTBP1 promotes growth factor-driven proliferation and activation of lung fibroblasts. Silencing CTBP1 reduced the degree of pulmonary fibrosis in mice with pulmonary fibrosis. Western blot, CO-IP, and BrdU assays confirmed that CTBP1 interacts with ZEB1 and promotes the activation of lung fibroblasts. Toosendanin can inhibit the ZEB1/CTBP1protein interaction and further inhibit the progression of pulmonary fibrosis.

CONCLUSION

CTBP1 can promote the activation and proliferation of lung fibroblasts through ZEB1. CTBP1 promotes lung fibroblast activation through ZEB1, thereby increasing excessive deposition of ECM and aggravating IPF. Toosendanin may be a potential treatment for pulmonary fibrosis. The results of this study provide a new basis for clarifying the molecular mechanism of pulmonary fibrosis and developing new therapeutic targets.

Amentoflavone Mitigates Cyclophosphamide-Induced Pulmonary Toxicity: Involvement of -SIRT-1/Nrf2/Keap1 Axis, JAK-2/STAT-3 Signaling, and Apoptosis

Background and objectives: Cyclophosphamide (CPA) is an alkylating agent that is used for the management of various types of malignancies and as an immunosuppressive agent for the treatment of immunological disorders. However, its use is limited by its potential to cause a wide range of pulmonary toxicities. Amentoflavone (AMV) is a flavonoid that had proven efficacy in the treatment of disease states in which oxidative stress, inflammation, and apoptosis may play a pathophysiologic role. This study investigated the potential ameliorative effects of the different doses of AMV on CPA-induced pulmonary toxicity, with special emphasis on its antioxidant, anti-inflammatory, and apoptosis-modulating effects. Materials and methods: In a rat model of CPA-induced pulmonary toxicity, the effect of AMV at two dose levels (50 mg/kg/day and 100 mg/kg/day) was investigated. The total and differential leucocytic counts, lactate dehydrogenase activity, and levels of pro-inflammatory cytokines in the bronchoalveolar lavage fluid were estimated. Also, the levels of oxidative stress parameters, sirtuin-1, Keap1, Nrf2, JAK2, STAT3, hydroxyproline, matrix metalloproteinases 3 and 9, autophagy markers, and the cleaved caspase 3 were assessed in the pulmonary tissues. In addition, the histopathological and electron microscopic changes in the pulmonary tissues were evaluated. Results: AMV dose-dependently ameliorated the pulmonary toxicities induced by CPA via modulation of the SIRT-1/Nrf2/Keap1 axis, mitigation of the inflammatory and fibrotic events, impaction of JAK-2/STAT-3 axis, and modulation of the autophagic and apoptotic signals. Conclusions: AMV may open new horizons towards the mitigation of the pulmonary toxicities induced by CPA.

Progress in Understanding the Role and Therapeutic Targets of Polarized Subtypes of Macrophages in Pulmonary Fibrosis

Pulmonary fibrosis represents the advanced phase of diverse pulmonary ailments, and at present, a definitive cure for these ailments is lacking. Furthermore, underlying mechanisms causative of these ailments remain elusive. Macrophages are immune cells that resist external stimuli in the early stages after birth. These cells can polarize into the classically (M1) and alternatively (M2) activated macrophages. When stimulated owing to the presence of toxic factors, M1 macrophages produce several pro-inflammatory factors, which mediate the inflammatory injury response of the alveolar tissue. The secretion of diverse growth factors by M2 macrophages contributes to the pathogenesis of aberrant alveolar structural fibrosis and remodeling. The abnormal activity of M2 macrophages is considered a critical factor in the formation of pulmonary fibrosis. In this mini-review, to highlight the clinical implications of research studies, we summarize the role and therapeutic targets of polarized subtypes of macrophages in pulmonary fibrosis and the role of targeting macrophages for the treatment of pulmonary fibrosis.

Excessive aggregation of fine particles may play a crucial role in adolescent spontaneous pneumothorax pathogenesis

Background

The pathogenesis of primary spontaneous pneumothorax (PSP) is unclear. Fine particles aggregated in the lung can be phagocytosed by alveolar macrophages (AMs) to induce an inflammatory reaction and damage local pulmonary tissue, which could be a mechanism of PSP. This project aimed to explore the pathological association between fine particulate matter and PSP.

Methods

Thirty pulmonary bullae tissues were obtained from surgery of PSP patients (B group). The adjacent normal tissues of the lungs were defined as the control S group. Another 30 normal lung tissues with nonpneumothorax disease (NPD) were applied as the control N group. Hematoxylin and eosin (H & E), Wright-Giemsa (W-G), Victoria blue, and immunohistochemical (IHC) staining experiments were performed to measure the levels of fine particulate matter, alveolar macrophages (AMs), pulmonary elastic fibers, monocyte chemoattractant protein-1 (MCP-1), and matrix metalloproteinase-9 (MMP-9) in the lung tissues. The serum levels of MCP-1 and MMP-9 were prospectively analyzed as well.

Results

Histopathological examinations revealed obvious deposition of fine particulate matter and inflammatory reactions (proliferation of AMs) in the B group, compared with those in the S group and the N group. These alterations were significantly associated with PSP. The numbers of AMs and pulmonary elastic fibers, the positive area of the H-score, as well as the concentrations of MCP-1 and MMP-9 in the lungs of the experimental group were obviously raised compared with the controls (P < 0.05).

Conclusions

Fine particulate matter aggregation, inflammation (macrophage hyperplasia), and overexpression of MCP-1 and MMP-9 may contribute to the pathogenesis of PSP. The overaccumulation of fine particulate matter may play a crucial part in the occurrence of adolescent and young adult PSP.

Trial registration

This project was enrolled on the Chinese Clinical Trial Registry: ChiCTR2100051460.

Detection of Pulmonary Fibrosis with a Collagen-Mimetic Peptide

Idiopathic pulmonary fibrosis (IPF) is a disease of unknown etiology that is characterized by excessive deposition and abnormal remodeling of collagen. IPF has a mean survival time of only 2-5 years from diagnosis, creating a need to detect IPF at an earlier stage when treatments might be more effective. We sought to develop a minimally invasive probe that could detect molecular changes in IPF-associated collagen. Here, we describe the design, synthesis, and performance of [68Ga]Ga·DOTA-CMP, which comprises a positron-emitting radioisotope linked to a collagen-mimetic peptide (CMP). This peptide mimics the natural structure of collagen and detects irregular collagen matrices by annealing to damaged collagen triple helices. We assessed the ability of the peptide to detect aberrant lung collagen selectively in a bleomycin-induced mouse model of pulmonary fibrosis using positron emission tomography (PET). [68Ga]Ga·DOTA-CMP PET demonstrated higher and selective uptake in a fibrotic mouse lung compared to controls, minimal background signal in adjacent organs, and rapid clearance via the renal system. These studies suggest that [68Ga]Ga·DOTA-CMP identifies fibrotic lungs and could be useful in the early diagnosis of IPF.

Pretreatment of UC-MSCs with IFN-α2 improves treatment of liver fibrosis by recruiting neutrophils

BACKGROUND

The use of umbilical cord mesenchymal stem cells (UC-MSCs) is a burgeoning method for the treatment of liver cirrhosis. However, the secretory phenotype and regulatory ability of UC-MSCs are easily affected by their microenvironment. Ensuring a specific microenvironment to enhance the UC-MSCs phenotype is a potential strategy for improving their therapeutic efficacy. The aim of this study was to explore therapeutic UC-MSCs phenotypes for improving liver fibrosis.

METHODS

RNA-sequencing was used to analyze the response pattern of UC-MSCs after exposure to the serum of cirrhotic patients with HBV. Using immunohistochemistry, quantitative polymerase chain reaction, and immunofluorescence techniques, we evaluated the therapeutic effect of UC-MSCs pretreated with interferon alpha 2 (IFN-α2) (pre-MSCs) in an animal model of cirrhosis. Immunoblotting, ELISA, and other techniques were used to analyze the signaling pathways underlying the IFN-induced changes in UC-MSCs.

RESULTS

UC-MSCs exposed to the serum of patients with hepatitis B-induced cirrhosis showed an enhanced response to type I IFN. The activated type I IFN signal induced the highest secretion of colony-stimulating factor 3 (CSF-3), interleukin (IL)-8, and chemokine (C-C motif) ligand 20 (CCL20) by the UC-MSCs. Pre-MSCs showed a higher therapeutic efficacy than untreated UC-MSCs in an animal model of liver fibrosis. Immunohistochemical analysis revealed that pre-MSCs could recruit neutrophils resulting in an increase in the secretion of matrix metalloprotease 8 that alleviated fibrosis. When neutrophils in animals were depleted, the therapeutic effect of pre-MSCs on fibrosis was inhibited. IFN-α2 altered the secretory phenotype of UC-MSCs by activating phosphorylated signal transducer and activator of transcription 1 and 2 (p-STAT1 and p-STAT2).

CONCLUSIONS

Pre-MSCs exhibited enhanced secretion of CSF-3, IL-8, and CCL20 and recruited neutrophils to alleviate fibrosis. This new strategy can improve cell therapy for liver cirrhosis.

Monoclonal enolase-1 blocking antibody ameliorates pulmonary inflammation and fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal disease with limited therapeutic options. The infiltration of monocytes and fibroblasts into the injured lungs is implicated in IPF. Enolase-1 (ENO1) is a cytosolic glycolytic enzyme which could translocate onto the cell surface and act as a plasminogen receptor to facilitate cell migration via plasmin activation. Our proprietary ENO1 antibody, HL217, was screened for its specific binding to ENO1 and significant inhibition of cell migration and plasmin activation (patent: US9382331B2).

METHODS

In this study, effects of HL217 were evaluated in vivo and in vitro for treating lung fibrosis.

RESULTS

Elevated ENO1 expression was found in fibrotic lungs in human and in bleomycin-treated mice. In the mouse model, HL217 reduced bleomycin-induced lung fibrosis, inflammation, body weight loss, lung weight gain, TGF-β upregulation in bronchial alveolar lavage fluid (BALF), and collagen deposition in lung. Moreover, HL217 reduced the migration of peripheral blood mononuclear cells (PBMC) and the recruitment of myeloid cells into the lungs. In vitro, HL217 significantly reduced cell-associated plasmin activation and cytokines secretion from primary human PBMC and endothelial cells. In primary human lung fibroblasts, HL217 also reduced cell migration and collagen secretion.

CONCLUSIONS

These findings suggest multi-faceted roles of cell surface ENO1 and a potential therapeutic approach for pulmonary fibrosis.

The Role of Immune Cells in the Pathogenesis of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating disease of unknown etiology with limited treatment options. The role of the immune system in IPF has received increasing attention. Uncontrolled immune responses drive the onset and progression of IPF. This article provides an overview of the role of innate immune cells (including macrophages, neutrophils, mast cells, eosinophils, dendritic cells, nature killer cells, nature kill cells and γδ T cells) and adaptive immune cells (including Th1 cells, Th2 cells, Th9 cells, Th17 cells, Th22 cells, cytotoxic T cells, B lymphocytes and Treg cells) in IPF. In addition, we review the current status of pharmacological treatments for IPF and new developments in immunotherapy. A deeper comprehension of the immune system's function in IPF may contribute to the development of targeted immunomodulatory therapies that can alter the course of the disease.

Catch your breath: The protective role of the angiotensin AT2 receptor for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease whereby excessive deposition of extracellular matrix proteins (ECM) ultimately leads to respiratory failure. While there have been advances in pharmacotherapies for pulmonary fibrosis, IPF remains an incurable and irreversible disease. There remains an unmet clinical need for treatments that reverse fibrosis, or at the very least have a more tolerable side effect profile than currently available treatments. Transforming growth factor β1(TGFβ1) is considered the main driver of fibrosis in IPF. However, as our understanding of the role of the pulmonary renin-angiotensin system (PRAS) in the pathogenesis of IPF increases, it is becoming clear that targeting angiotensin receptors represents a potential novel treatment strategy for IPF - in particular, via activation of the anti-fibrotic angiotensin type 2 receptor (AT2R). This review describes the current understanding of the pathophysiology of IPF and the mediators implicated in its pathogenesis; focusing on TGFβ1, angiotensin II and related peptides in the PRAS and their contribution to fibrotic processes in the lung. Preclinical and clinical assessment of currently available AT2R agonists and the development of novel, highly selective ligands for this receptor will also be described, with a focus on compound 21, currently in clinical trials for IPF. Collectively, this review provides evidence of the potential of AT2R as a novel therapeutic target for IPF.

Molecular and Genetic Biomarkers in Idiopathic Pulmonary Fibrosis: Where Are We Now?

Idiopathic pulmonary fibrosis (IPF) represents a chronic progressive fibrotic interstitial lung disease of unknown cause with an ominous prognosis. It remains an unprecedent clinical challenge due to its delayed diagnosis and unpredictable clinical course. The need for accurate diagnostic, prognostic and predisposition biomarkers in everyday clinical practice becomes more necessary than ever to ensure prompt diagnoses and early treatment. The identification of such blood biomarkers may also unravel novel drug targets against IPF development and progression. So far, the role of diverse blood biomarkers, implicated in various pathogenetic pathways, such as in fibrogenesis (S100A4), extracellular matrix remodelling (YKL-40, MMP-7, ICAM-1, LOXL2, periostin), chemotaxis (CCL-18, IL-8), epithelial cell injury (KL-6, SP-A, SP-D), autophagy and unfolded protein response has been investigated in IPF with various results. Moreover, the recent progress in genetics in IPF allows for a better understanding of the underlying disease mechanisms. So far, the causative mutations in pulmonary fibrosis include mutations in telomere-related genes and in surfactant-related genes, markers that could act as predisposition biomarkers in IPF. The aim of this review is to provide a comprehensive overview from the bench to bedside of current knowledge and recent insights on biomarkers in IPF, and to suggest future directions for research. Large-scale studies are still needed to confirm the exact role of these biomarkers.

Triptolide attenuates pulmonary fibrosis by inhibiting fibrotic extracellular matrix remodeling mediated by MMPs/LOX/integrin

BACKGROUND

Fibrotic extracellular matrix (ECM) remodeling characterized different types of pulmonary fibrosis, and its regulation could be a potential shared treatment strategy for pulmonary fibrosis.

PURPOSE

We aimed to investigate the effect of triptolide on pulmonary fibrosis through the inhibition of several important aspects of fibrotic ECM remodeling.

METHODS

Bleomycin-induced pulmonary fibrosis mice and TGF-β1-induced primary lung fibroblasts were used. The effect of triptolide on pulmonary fibrosis was detected using histopathology, immunostaining, RT-qPCR, western blotting, ELISA, and protein activity assay.

RESULTS

Triptolide significantly alleviated bleomycin-induced pulmonary fibrosis in mice. It inhibited the expression of fibrotic genes α-SMA, collagen I, fibronectin, and vimentin and blocked the TGF-β-SMAD signaling pathway both in vivo and in vitro. In addition, triptolide regulated the expression and activity of MMPs during fibrosis. Interestingly, it suppressed the expression of lysyl oxidase, which was responsible for matrix cross-linking and elevated ECM stiffness. Furthermore, triptolide blocked the biomechanical stress transduction pathway integrin-β1-FAK-YAP signaling and attenuated the pro-fibrotic feedback of fibrotic ECM on fibroblasts via integrin inhibition.

CONCLUSION

These findings show that triptolide prevents the key linkages of fibrotic ECM remodeling, including deposition, degradation, cross-linking, and pro-fibrotic feedback and, therefore, has potential therapeutic value for pulmonary fibrosis.

Survival and soluble immune mediators of immune checkpoint inhibitor-induced interstitial lung disease in patients with non-small cell lung cancer

BACKGROUND

Immune checkpoint inhibitor-related interstitial lung disease (ICI-ILD) is a serious adverse event frequently observed in patients with non-small cell lung cancer (NSCLC). We investigated the clinical effects and mechanism of action of ICI-ILD in NSCLC patients treated with ICI.

METHODS

We retrospectively screened patients with advanced or recurrent NSCLC who received PD-1/PD-L1 inhibitor monotherapy and examined the prognostic impact of ICI-ILD. In addition, we analyzed the levels of 72 different soluble immune mediators in pre-treatment plasma to explore possible mechanisms associated with the development of ICI-ILD. Furthermore, the relationships between soluble immune mediators associated with ICI-ILD development and survival were analyzed.

RESULTS

Of 141 patients with NSCLC, 25 (17.7%) developed ICI-ILD. Logistic regression analysis revealed that pre-treatment CXCL9, MMP-1, IL-6, and IL-19 levels were associated with ICI-ILD development. There were no significant differences in progression-free survival (PFS) and overall survival (OS) between patients with or without ICI-ILD. In patients with ICI-ILD, patients with lower grade ICI-ILD had better OS than those with higher-grade ICI-ILD. In ICI-ILD patients, there was a trend for patients with lower-grade ICI-ILD to have better PFS and OS than those with higher-grade ICI-ILD. Among four soluble immune mediators associated with ICI-ILD, a high level of IL-19 was significantly correlated with worse OS and PFS.

CONCLUSION

The identified soluble immune mediators, including CXCL9, MMP-1, IL-6, and IL-19, may be useful as biomarkers to associate with ICI-ILD development. Although we did not detect significant differences in PFS and OS between patients with and without ICI-ILD, PFS and OS were longer in those with lower-grade ICI-ILD than in patients with higher-grade ICI-ILD. Among biomarkers, IL-19 may be a causal and prognostic factor for ICI-ILD.

Fibroblast growth factor 2 acts as an upstream regulator of inhibition of pulmonary fibroblast activation

Fibroblast growth factor (FGF) signaling plays a crucial role in lung development and repair. Fibroblast growth factor 2 (FGF2) can inhibit fibrotic gene expression and suppress the differentiation of pulmonary fibroblasts (PFs) into myofibroblasts in vitro, suggesting that FGF2 is a potential target for inhibiting pulmonary fibrosis. To gain deeper insights into the molecular mechanism underlying FGF2-mediated regulation of PFs, we performed mRNA sequencing analysis to systematically and globally uncover the regulated genes and biological functions of FGF2 in PFs. Gene Ontology analysis revealed that the differentially expressed genes regulated by FGF2 were enriched in multiple cellular functions including extracellular matrix (ECM) organization, cytoskeleton formation, β-catenin-independent Wnt signaling pathway, supramolecular fiber organization, epithelial cell proliferation, and cell adhesion. Gene Set Enrichment Analysis and cellular experiments confirmed that FGF2 can suppress ECM and actin filament organization and increase PFs proliferation. Taken together, these findings indicate that FGF2 acts as an upstream regulator of the inhibition of PFs activation and may play a regulatory role in pulmonary fibrosis.

Circulating biomarkers of extracellular matrix dysregulation are associated with adverse post-stage 2 outcomes in infants with single ventricle heart disease

Children with single ventricle heart disease (SVHD) experience morbidity due to inadequate pulmonary blood flow. Using proteomic screening, our group previously identified members of the matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinase (TIMP), and fibroblast growth factor (FGF) families as potentially dysregulated in SVHD. No prior study has taken a targeted approach to mapping circulating levels of these protein families or their relationship to pulmonary vascular outcomes in SVHD. We performed a prospective cohort study of 70 SVHD infants pre-Stage 2 palliation and 24 healthy controls. We report targeted serum quantification of 39 proteins in the MMP, TIMP, and FGF families using the SomaScan platform. Clinical variables were extracted from the medical record. Twenty of 39 tested proteins (7/14 MMPs, 2/4 TIMPs, and 11/21 FGFs) differed between cases and controls. On single variable testing, 6 proteins and no clinical covariates were associated with both post-Stage 2 hypoxemia and length of stay. Multiple-protein modeling identified increased circulating MMP 7 and MMP 17, and decreased circulating MMP 8 and FGFR2 as most associated with post-Stage 2 hypoxemia; increased MMP 7 and TIMP 4 and decreased circulating MMP 1 and MMP 8 were most associated with post-operation length of stay. The MMP, TIMP, and FGF families are altered in SVHD. Pre-Stage 2 imbalance of extracellular matrix (ECM) proteins-increased MMP 7 and decreased MMP 8-was associated with multiple adverse post-operation outcomes. Maintenance of the ECM may be an important pathophysiologic driver of Stage 2 readiness in SVHD.

Dynamic atlas of immune cells reveals multiple functional features of macrophages associated with progression of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease with a high mortality rate and unclarified aetiology. Immune response is elaborately regulated during the progression of IPF, but immune cells subsets are complicated which has not been detailed described during IPF progression. Therefore, in the current study, we sought to investigate the role of immune regulation by elaborately characterize the heterogeneous of immune cells during the progression of IPF. To this end, we performed single-cell profiling of lung immune cells isolated from four stages of bleomycin-induced pulmonary fibrosis-a classical mouse model that mimics human IPF. The results revealed distinct components of immune cells in different phases of pulmonary fibrosis and close communication between macrophages and other immune cells along with pulmonary fibrosis progression. Enriched signals of SPP1, CCL5 and CXCL2 were found between macrophages and other immune cells. The more detailed definition of the subpopulations of macrophages defined alveolar macrophages (AMs) and monocyte-derived macrophages (mo-Macs)-the two major types of primary lung macrophages-exhibited the highest heterogeneity and dynamic changes in expression of profibrotic genes during disease progression. Our analysis suggested that Gpnmb and Trem2 were both upregulated in macrophages and may play important roles in pulmonary fibrosis progression. Additionally, the metabolic status of AMs and mo-Macs varied with disease progression. In line with the published data on human IPF, macrophages in the mouse model shared some features regarding gene expression and metabolic status with that of macrophages in IPF patients. Our study provides new insights into the pathological features of profibrotic macrophages in the lung that will facilitate the identification of new targets for disease intervention and treatment of IPF.

A construct of adipose-derived mesenchymal stem cells-laden collagen scaffold for fertility restoration by inhibiting fibrosis in a rat model of endometrial injury

Severe endometrium damage causes pathological conditions such as thin endometrium and intrauterine adhesion, resulting in uterine factor infertility. Mesenchymal stem cell (MSC) therapy is a promising strategy in endometrial repair; yet, exogenous MSCs still raise concerns for safety and ethical issues. Human adipose-derived mesenchymal stem cells (ADMSCs) residing in adipose tissue have high translational potentials due to their autologous origin. To harness the high translation potentials of ADMSC in clinical endometrium regeneration, here we constructed an ADMSCs composited porous scaffold (CS/ADMSC) and evaluated its effectiveness on endometrial regeneration in a rat endometrium-injury model. We found that CS/ADMSC intrauterine implantation (i) promoted endometrial thickness and gland number, (ii) enhanced tissue angiogenesis, (iii) reduced fibrosis and (iv) restored fertility. We ascertained the pro-proliferation, pro-angiogenesis, immunomodulating and anti-fibrotic effects of CS/ADMSC in vitro and revealed that the CS/ADMSC influenced extracellular matrix composition and organization by a transcriptomic analysis. Our results demonstrated the effectiveness of CS/ADMSC for endometrial regeneration and provided solid proof for our future clinical study.

NETosis promotes chronic inflammation and fibrosis in systemic lupus erythematosus and COVID-19

Pulmonary fibrosis, a serious complication of systemic lupus erythematosus (SLE) and coronavirus disease 2019 (COVID-19), leads to irreversible lung damage. However, the underlying mechanism of this condition remains unclear. In this study, we revealed the landscape of transcriptional changes in lung biopsies from individuals with SLE, COVID-19-induced pulmonary fibrosis, and idiopathic pulmonary fibrosis (IPF) using histopathology and RNA sequencing, respectively. Despite the diverse etiologies of these diseases, lung expression of matrix metalloproteinase genes in these diseases showed similar patterns. Particularly, the differentially expressed genes were significantly enriched in the pathway of neutrophil extracellular trap formation, showing similar enrichment signature between SLE and COVID-19. The abundance of Neutrophil extracellular traps (NETs) was much higher in the lungs of individuals with SLE and COVID-19 compared to those with IPF. In-depth transcriptome analyses revealed that NETs formation pathway promotes epithelial-mesenchymal transition (EMT). Furthermore, stimulation with NETs significantly up-regulated α-SMA, Twist, Snail protein expression, while decreasing the expression of E-cadherin protein in vitro. This indicates that NETosis promotes EMT in lung epithelial cells. Given drugs that are efficacious in degrading damaged NETs or inhibiting NETs production, we identified a few drug targets that were aberrantly expressed in both SLE and COVID-19. Among these targets, the JAK2 inhibitor Tofacitinib could effectively disrupted the process of NETs and reversed NET-induced EMT in lung epithelial cells. These findings support that the NETs/EMT axis, activated by SLE and COVID-19, contributes to the progression of pulmonary fibrosis. Our study also highlights that JAK2 as a potential target for the treatment of fibrosis in these diseases.

Underlying Molecular Mechanism and Construction of a miRNA-Gene Network in Idiopathic Pulmonary Fibrosis by Bioinformatics

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease, but its pathogenesis is still unclear. Bioinformatics methods were used to explore the differentially expressed genes (DEGs) and to elucidate the pathogenesis of IPF at the genetic level. The microarray datasets GSE110147 and GSE53845 were downloaded from the Gene Expression Omnibus (GEO) database and analyzed using GEO2R to obtain the DEGs. The DEGs were further analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genomes (KEGG) pathway enrichment using the DAVID database. Then, using the STRING database and Cytoscape, a protein-protein interaction (PPI) network was created and the hub genes were selected. In addition, lung tissue from a mouse model was validated. Lastly, the network between the target microRNAs (miRNAs) and the hub genes was constructed with NetworkAnalyst. A summary of 240 genes were identified as DEGs, and functional analysis highlighted their role in cell adhesion molecules and ECM-receptor interactions in IPF. In addition, eight hub genes were selected. Four of these hub genes (VCAM1, CDH2, SPP1, and POSTN) were screened for animal validation. The IHC and RT-qPCR of lung tissue from a mouse model confirmed the results above. Then, miR-181b-5p, miR-4262, and miR-155-5p were predicted as possible key miRNAs. Eight hub genes may play a key role in the development of IPF. Four of the hub genes were validated in animal experiments. MiR-181b-5p, miR-4262, and miR-155-5p may be involved in the pathophysiological processes of IPF by interacting with hub genes.

Advancing Treatment Strategies: A Comprehensive Review of Drug Delivery Innovations for Chronic Inflammatory Respiratory Diseases

Chronic inflammatory respiratory diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis, present ongoing challenges in terms of effective treatment and management. These diseases are characterized by persistent inflammation in the airways, leading to structural changes and compromised lung function. There are several treatments available for them, such as bronchodilators, immunomodulators, and oxygen therapy. However, there are still some shortcomings in the effectiveness and side effects of drugs. To achieve optimal therapeutic outcomes while minimizing systemic side effects, targeted therapies and precise drug delivery systems are crucial to the management of these diseases. This comprehensive review focuses on the role of drug delivery systems in chronic inflammatory respiratory diseases, particularly nanoparticle-based drug delivery systems, inhaled corticosteroids (ICSs), novel biologicals, gene therapy, and personalized medicine. By examining the latest advancements and strategies in these areas, we aim to provide a thorough understanding of the current landscape and future prospects for improving treatment outcomes in these challenging conditions.

Acute Exacerbations of Interstitial Lung Diseases: Focus on Biomarkers

Interstitial lung diseases (ILDs) are a large group of pulmonary disorders characterized histologically by the cardinal involvement of the pulmonary interstitium. The prototype of ILDs is idiopathic pulmonary fibrosis (IPF), an incurable disease characterized by progressive distortion and loss of normal lung architecture through unchecked collagen deposition. Acute exacerbations are dramatic events during the clinical course of ILDs, associated with high morbidity and mortality. Infections, microaspiration, and advanced lung disease might be involved in the pathogenesis of acute exacerbations. Despite clinical scores, the prediction of the onset and outcome of acute exacerbations is still inaccurate. Biomarkers are necessary to characterize acute exacerbations better. We review the evidence for alveolar epithelial cell, fibropoliferation, and immunity molecules as potential biomarkers for acute exacerbations of interstitial lung disease.

Sparganii Rhizoma alleviates pulmonary fibrosis by inhibiting fibroblasts differentiation and epithelial-mesenchymal transition mediated by TGF-β1/ Smad2/3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary fibrosis (PF), a lethal lung disease, can lead to structural destruction of the alveoli until death. Sparganii Rhizoma (SR), primarily distributed in East Asia, has been used clinically for hundreds of years against organ fibrosis and inflammation.

AIM OF THE STUDY

We intended to verify the effect of SR alleviate PF and further explore mechanisms.

METHODS

Murine model of PF was established by endotracheal infusion of bleomycin. We detected the anti-PF effect of SR through lung coefficient, hydroxyproline content, lung function and pathological staining. Then, we used Western Blot and RT-PCR to verify the mechanism. In vitro experiments, MRC-5 and BEAS-2B were induced to phenotypic transformation by TGF-β1 and then RT-PCR, WB and IF were conducted to verify the effect of SR.

RESULTS

SR significantly reduced BLM-induced PF in mice, improved lung function, slowed the degree of lung tissue lesions, and reduced collagen deposition. SR alleviated PF by inhibiting fibroblasts differentiation and epithelial-mesenchymal transition. In vivo studies explored the mechanism and found that it was related to TGF-β1/Smad2/3 pathway.

CONCLUSIONS

Our research proved SR could effectively treat PF, providing a fresh idea and approach for the treatment of PF with traditional Chinese medicine.

Reviewing the Regulators of COL1A1

The collagen family contains 28 proteins, predominantly expressed in the extracellular matrix (ECM) and characterized by a triple-helix structure. Collagens undergo several maturation steps, including post-translational modifications (PTMs) and cross-linking. These proteins are associated with multiple diseases, the most pronounced of which are fibrosis and bone diseases. This review focuses on the most abundant ECM protein highly implicated in disease, type I collagen (collagen I), in particular on its predominant chain collagen type I alpha 1 (COLα1 (I)). An overview of the regulators of COLα1 (I) and COLα1 (I) interactors is presented. Manuscripts were retrieved searching PubMed, using specific keywords related to COLα1 (I). COL1A1 regulators at the epigenetic, transcriptional, post-transcriptional and post-translational levels include DNA Methyl Transferases (DNMTs), Tumour Growth Factor β (TGFβ), Terminal Nucleotidyltransferase 5A (TENT5A) and Bone Morphogenic Protein 1 (BMP1), respectively. COLα1 (I) interacts with a variety of cell receptors including integrinβ, Endo180 and Discoidin Domain Receptors (DDRs). Collectively, even though multiple factors have been identified in association to COLα1 (I) function, the implicated pathways frequently remain unclear, underscoring the need for a more spherical analysis considering all molecular levels simultaneously.

Involvement of Matrix Metalloproteinases in COVID-19: Molecular Targets, Mechanisms, and Insights for Therapeutic Interventions

MMPs are enzymes involved in SARS-CoV-2 pathogenesis. Notably, the proteolytic activation of MMPs can occur through angiotensin II, immune cells, cytokines, and pro-oxidant agents. However, comprehensive information regarding the impact of MMPs in the different physiological systems with disease progression is not fully understood. In the current study, we review the recent biological advances in understanding the function of MMPs and examine time-course changes in MMPs during COVID-19. In addition, we explore the interplay between pre-existing comorbidities, disease severity, and MMPs. The reviewed studies showed increases in different MMP classes in the cerebrospinal fluid, lung, myocardium, peripheral blood cells, serum, and plasma in patients with COVID-19 compared to non-infected individuals. Individuals with arthritis, obesity, diabetes, hypertension, autoimmune diseases, and cancer had higher MMP levels when infected. Furthermore, this up-regulation may be associated with disease severity and the hospitalization period. Clarifying the molecular pathways and specific mechanisms that mediate MMP activity is important in developing optimized interventions to improve health and clinical outcomes during COVID-19. Furthermore, better knowledge of MMPs will likely provide possible pharmacological and non-pharmacological interventions. This relevant topic might add new concepts and implications for public health in the near future.