The chemokine CCL1 triggers an AMFR-SPRY1 pathway that promotes differentiation of lung fibroblasts into myofibroblasts and drives pulmonary fibrosis

VISTA Deficiency Exacerbates the Development of Pulmonary Fibrosis by Promoting Th17 Differentiation

Background

Interstitial lung disease (ILD), characterized by pulmonary fibrosis (PF), represents the end-stage of various ILDs. The immune system plays an important role in the pathogenesis of PF. V-domain immunoglobulin suppressor of T-cell activation (VISTA) is an immune checkpoint with immune suppressive functions. However, its specific role in the development of PF and the underlying mechanisms remain to be elucidated.

Methods

We assessed the expression of VISTA in CD4 T cells from patients with connective tissue disease-related interstitial lung disease (CTD-ILD). Spleen cells from wild-type (WT) or Vsir -/- mice were isolated and induced for cell differentiation in vitro. Additionally, primary lung fibroblasts were isolated and treated with interleukin-17A (IL-17A). Mice were challenged with bleomycin (BLM) following VISTA blockade or Vsir knockout. Moreover, WT or Vsir -/- CD4 T cells were transferred into Rag1 -/- mice, which were then challenged with BLM.

Results

VISTA expression was decreased in CD4 T cells from patients with CTD-ILD. Vsir deficiency augmented T-helper 17 (Th17) cell differentiation in vitro. Furthermore, IL-17A enhanced the production of inflammatory cytokines, as well as the differentiation and migration of lung fibroblasts. Both VISTA blockade and knockout of Vsir increased the percentage of IL-17A-producing Th17 cells and promoted BLM-induced PF. In addition, mice receiving Vsir -/- CD4 T cells exhibited a higher percentage of Th17 cells and more severe PF compared to those receiving WT CD4 T cells.

Conclusion

These findings demonstrate the significant role of VISTA in modulating the development of PF by controlling Th17 cell differentiation. These insights suggest that targeting VISTA could be a promising therapeutic strategy for PF.

Bortezomib restrains M2 polarization and reduces CXCL16-associated CXCR6+CD4 T cell chemotaxis in bleomycin-induced pulmonary fibrosis

BACKGROUND

The development of pulmonary fibrosis involves a cascade of events, in which inflammation mediated by immune cells plays a pivotal role. Chemotherapeutic drugs have been shown to have dual effects on fibrosis, with bleomycin exacerbating pulmonary fibrosis and bortezomib alleviating tissue fibrotic processes. Understanding the intricate interplay between chemotherapeutic drugs, immune responses, and pulmonary fibrosis is likely to serve as the foundation for crafting tailored therapeutic strategies.

METHODS

A model of bleomycin-induced pulmonary fibrosis was established, followed by treatment with bortezomib. Tissue samples were collected for analysis of immune cell subsets and functional assessment by flow cytometry and in vitro cell experiments. Additionally, multi-omics analysis was conducted to further elucidate the expression of chemokines and chemokine receptors, as well as the characteristics of cell populations.

RESULTS

Here, we observed that the expression of CXCL16 and CXCR6 was elevated in the lung tissue of a pulmonary fibrosis model. In the context of pulmonary fibrosis or TGF-β1 stimulation in vitro, macrophages exhibited an M2-polarized phenotype and secreted more CXCL16 than those of the control group. Moreover, flow cytometry revealed increased expression levels of CD69 and CXCR6 in pulmonary CD4 T cells during fibrosis progression. The administration of bortezomib alleviated bleomycin-induced pulmonary fibrosis, accompanied by reduced ratio of M2-polarized macrophages and decreased accumulation of CD4 T cells expressing CXCR6.

CONCLUSIONS

Our findings provide insights into the key immune players involved in bleomycin-induced pulmonary fibrosis and offer preclinical evidence supporting the repurposing strategy and combination approaches to reduce lung fibrosis.

Nanoparticle/Engineered Bacteria Based Triple-Strategy Delivery System for Enhanced Hepatocellular Carcinoma Cancer Therapy

Background

New treatment modalities for hepatocellular carcinoma (HCC) are desperately critically needed, given the lack of specificity, severe side effects, and drug resistance with single chemotherapy. Engineered bacteria can target and accumulate in tumor tissues, induce an immune response, and act as drug delivery vehicles. However, conventional bacterial therapy has limitations, such as drug loading capacity and difficult cargo release, resulting in inadequate therapeutic outcomes. Synthetic biotechnology can enhance the precision and efficacy of bacteria-based delivery systems. This enables the selective release of therapeutic payloads in vivo.

Methods

In this study, we constructed a non-pathogenic Escherichia coli (E. coli) with a synchronized lysis circuit as both a drug/gene delivery vehicle and an in-situ (hepatitis B surface antigen) Ag (ASEc) producer. Polyethylene glycol (CHO-PEG2000-CHO)-poly(ethyleneimine) (PEI25k)-citraconic anhydride (CA)-doxorubicin (DOX) nanoparticles loaded with plasmid encoded human sulfatase 1 (hsulf-1) enzyme (PNPs) were anchored on the surface of ASEc (ASEc@PNPs). The composites were synthesized and characterized. The in vitro and in vivo anti-tumor effect of ASEc@PNPs was tested in HepG2 cell lines and a mouse subcutaneous tumor model.

Results

The results demonstrated that upon intravenous injection into tumor-bearing mice, ASEc can actively target and colonise tumor sites. The lytic genes to achieve blast and concentrated release of Ag significantly increased cytokine secretion and the intratumoral infiltration of CD4/CD8+T cells, initiated a specific immune response. Simultaneously, the PNPs system releases hsulf-1 and DOX into the tumor cell resulting in rapid tumor regression and metastasis prevention.

Conclusion

The novel drug delivery system significantly suppressed HCC in vivo with reduced side effects, indicating a potential strategy for clinical HCC therapy.

Loss of ZNF451 mediates fibroblast activation and promotes lung fibrosis

BACKGROUND

No effective therapies for pulmonary fibrosis (PF) exist because of the unclear molecular pathogenesis and the lack of effective therapeutic targets. Zinc finger protein 451 (ZNF451), a transcriptional regulator, plays crucial roles in the pathogenesis of several diseases. However, its expression pattern and function in PF remain unknown. This study was designed to investigate the role of ZNF451 in the pathogenesis of lung fibrosis.

METHODS

GEO dataset analysis, RT‒PCR, and immunoblot assays were used to examine the expression of ZNF451 in PF; ZNF451 knockout mice and ZNF451-overexpressing lentivirus were used to determine the importance of ZNF451 in PF progression; and migration assays, immunofluorescence staining, and RNA-seq analysis were used for mechanistic studies.

RESULTS

ZNF451 is downregulated and negatively associated with disease severity in PF. Compared with wild-type (WT) mice, ZNF451 knockout mice exhibited much more serious PF changes. However, ZNF451 overexpression protects mice from BLM-induced pulmonary fibrosis. Mechanistically, ZNF451 downregulation triggers fibroblast activation by increasing the expression of PDGFB and subsequently activating PI3K/Akt signaling.

CONCLUSION

These findings uncover a critical role of ZNF451 in PF progression and introduce a novel regulatory mechanism of ZNF451 in fibroblast activation. Our study suggests that ZNF451 serves as a potential therapeutic target for PF and that strategies aimed at increasing ZNF451 expression may be promising therapeutic approaches for PF.

Comprehensive review of potential drugs with anti-pulmonary fibrosis properties

Pulmonary fibrosis is a chronic and progressive lung disease characterized by the accumulation of scar tissue in the lungs, which leads to impaired lung function and reduced quality of life. The prognosis for idiopathic pulmonary fibrosis (IPF), which is the most common form of pulmonary fibrosis, is generally poor. The median survival for patients with IPF is estimated to be around 3-5 years from the time of diagnosis. Currently, there are two approved drugs (Pirfenidone and Nintedanib) for the treatment of IPF. However, Pirfenidone and Nintedanib are not able to reverse or cure pulmonary fibrosis. There is a need for new pharmacological interventions that can slow or halt disease progression and cure pulmonary fibrosis. This review aims to provide an updated overview of current and future drug interventions for idiopathic pulmonary fibrosis, and to summarize possible targets of potential anti-pulmonary fibrosis drugs, providing theoretical support for further clinical combination therapy or the development of new drugs.

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.

Arginine methylation and respiratory disease

Arginine methylation, a vital post-translational modification, plays a pivotal role in numerous cellular functions such as signal transduction, DNA damage response and repair, regulation of gene transcription, mRNA splicing, and protein interactions. Central to this modification is the role of protein arginine methyltransferases (PRMTs), which have been increasingly recognized for their involvement in the pathogenesis of various respiratory diseases. This review begins with an exploration of the biochemical underpinnings of arginine methylation, shedding light on the intricate molecular regulatory mechanisms governed by PRMTs. It then delves into the impact of arginine methylation and the dysregulation of arginine methyltransferases in diverse pulmonary disorders. Concluding with a focus on the therapeutic potential and recent advancements in PRMT inhibitors, this article aims to offer novel perspectives and therapeutic avenues for the management and treatment of respiratory diseases.

IRF4 Participates in Pulmonary Fibrosis Induced by Silica Particles through Regulating Macrophage Polarization and Fibroblast Activation

Long-term exposure to silica dust can cause silicosis, which is characterized by chronic progressive inflammatory injury, fibroblast activation, and the deposition of extracellular matrix. IRF4 is involved in immune response. However, the potential regulation of IRF4 in silicosis and pulmonary fibrosis remains largely unexplored. In this study, RNA-seq analysis identified the upregulated expression of IRF4 in fibrotic lung tissues of mice exposed to silica particles. And we verified the increased expression of IRF4 in SiO2-treated macrophages and TGF-β1-treated fibroblasts. We further found that the down-regulation of IRF4 impeded the macrophage polarization and the release of pro-fibrotic factors. Moreover, the down-regulation of IRF4 alleviated the migration, invasion, and the expression of fibrotic molecules in fibroblasts. Using ChIP-qPCR assay, we confirmed that IRF4 regulated the transcriptional activity of the IL-17A promoter, thus stimulated fibroblast activation, migration and invasion. In vivo experiment, the AAV-siIRF4 was designed to interfere with the expression of IRF4 in lung tissues of mice exposed to silica particles. Whole blood, bronchoalveolar lavage fluid and lung tissues were obtained from mice at 7, 14, 28 and 56 days after silica exposure. The results showed that the leukocyte content and inflammatory factors reached a peak at day 14 and remained peak for a long time after IRF4 knockdown. Furthermore, the fibrotic responses of mouse lung tissues were alleviated after IRF4 knockdown. Our study explored the important roles of IRF4 in inflammatory and fibrotic responses, which provided a new target for the treatment of silicosis and pulmonary fibrosis.

Pulmonary Surfactant Homeostasis Dysfunction Mediates Multiwalled Carbon Nanotubes Induced Lung Fibrosis via Elevating Surface Tension

Multiwalled carbon nanotubes (MWCNTs) have been widely used in many disciplines and raised great concerns about their negative health impacts, especially environmental and occupational exposure. MWCNTs have been reported to induce fibrotic responses; however, the underlying mechanisms remain largely veiled. Here, we reported that MWCNTs inhalation induced lung fibrosis together with decreased lung compliance, increased elastance in the mice model, and elevated surface tension in vitro. Specifically, MWCNTs increased surface tension by impairing the function of the pulmonary surfactant. Mechanistically, MWCNTs induced lamellar body (LB) dysfunction through autophagy dysfunction, which then leads to surface tension elevated by pulmonary surfactant dysfunction in the context of lung fibrosis. This is a study to investigate the molecular mechanism of MWCNTs-induced lung fibrosis and focus on surface tension. A direct mechanistic link among impaired LBs, surface tension, and fibrosis has been established. This finding elucidates the detailed molecular mechanisms of lung fibrosis induced by MWCNTs. It also highlights that pulmonary surfactants are expected to be potential therapeutic targets for the prevention and treatment of lung fibrosis induced by MWCNTs.

Standigm ASK™: knowledge graph and artificial intelligence platform applied to target discovery in idiopathic pulmonary fibrosis

Standigm ASK™ revolutionizes healthcare by addressing the critical challenge of identifying pivotal target genes in disease mechanisms-a fundamental aspect of drug development success. Standigm ASK™ integrates a unique combination of a heterogeneous knowledge graph (KG) database and an attention-based neural network model, providing interpretable subgraph evidence. Empowering users through an interactive interface, Standigm ASK™ facilitates the exploration of predicted results. Applying Standigm ASK™ to idiopathic pulmonary fibrosis (IPF), a complex lung disease, we focused on genes (AMFR, MDFIC and NR5A2) identified through KG evidence. In vitro experiments demonstrated their relevance, as TGFβ treatment induced gene expression changes associated with epithelial-mesenchymal transition characteristics. Gene knockdown reversed these changes, identifying AMFR, MDFIC and NR5A2 as potential therapeutic targets for IPF. In summary, Standigm ASK™ emerges as an innovative KG and artificial intelligence platform driving insights in drug target discovery, exemplified by the identification and validation of therapeutic targets for IPF.

Tolerogenic dendritic cells in radiation-induced lung injury

Radiation-induced lung injury is a common complication associated with radiotherapy. It is characterized by early-stage radiation pneumonia and subsequent radiation pulmonary fibrosis. However, there is currently a lack of effective therapeutic strategies for radiation-induced lung injury. Recent studies have shown that tolerogenic dendritic cells interact with regulatory T cells and/or regulatory B cells to stimulate the production of immunosuppressive molecules, control inflammation, and prevent overimmunity. This highlights a potential new therapeutic activity of tolerogenic dendritic cells in managing radiation-induced lung injury. In this review, we aim to provide a comprehensive overview of tolerogenic dendritic cells in the context of radiation-induced lung injury, which will be valuable for researchers in this field.

Autocrine motility factor receptor promotes the malignancy of glioblastoma by regulating cell migration and invasion

OBJECTIVE

One of the important causes of death in cancer patients is malignant metastasis, invasion, and metastasis of tumor cells. Metastasis is also the most basic physiological characteristics and pathogenesis of various tumors. Previously published studies have suggested that autocrine motor factor receptor (AMFR) is the key regulator of tumor cell migration and invasion. Meanwhile, AMFR is highly expressed in esophageal tumors, gastrointestinal tumors, and bladder cancer, and it is also involved in its pathogenesis. However, the role of AMFR in glioblastoma has not been reported.

METHODS

In order to study the role of AMFR in the cell migration and invasion of glioblastoma, AMFR was silenced using siRNA and overexpressed using cDNA. Immunoblotting analysis and real-time quantitative polymerase chain reaction (PCR) were employed to assess the expression of AMFR. We conducted wound healing assay, cell migration assay, and tumorsphere formation assay to detect the invasion and metastatic ability of glioblastoma.

RESULTS

This study found that the level of AMFR expression was significantly correlated with the malignant degree of glioma tissue in clinic samples. AMFR silencing decreased cell migration and invasion of LN229. Overexpression of AMFR significantly increased cell migration and invasion of U251.

CONCLUSION

This study suggests that AMFR could be used as a therapeutic strategy for the clinical treatment of glioblastoma.

Mechanisms of fibrosis in iatrogenic laryngotracheal stenosis: New discoveries and novel targets

Iatrogenic laryngotracheal stenosis (iLTS) is a pathological condition characterized by the narrowing of the laryngeal and tracheal structures due to the formation of abnormal scar tissue. The core of iLTS lies in the fibrosis of the laryngotracheal tissue, and recent research has unveiled novel discoveries regarding the underlying mechanisms of fibrosis. This review provides an overview of the recent advancements in understanding the mechanisms of fibrosis in iLTS. It encompasses various aspects, such as immune system dysregulation, changes in the extracellular matrix (ECM), metabolic alterations, and the role of microbial flora. The review also explores the interplay and relationships between these new mechanisms, establishing a theoretical foundation for the development of multi-target therapies and combination therapies for iLTS.

Identification and Validation of Genes Exhibiting Dynamic Alterations in Response to Bleomycin-Induced Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) carries a high mortality rate and has a poor prognosis. The pathogenesis of pulmonary fibrosis (PF) is highly related to dysregulation of multiple RNAs. This study aims to identify and validate dysregulated RNAs that exhibited dynamic alterations in response to bleomycin (BLM)-induced PF. The results will provide therapeutic targets for patients suffering from IPF. Whole transcriptomic profiles of BLM-induced PF were obtained through high-throughput RNA sequencing. miRNA profiling was downloaded from GSE45789 database in the Gene Expression Omnibus (GEO). We identified the differentially expressed RNAs (DERNAs) that exhibited dynamic alterations in response to BLM-induced PF. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway enrichment analysis were conducted to discovery regulatory processes of PF. Weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI) analysis, and co-expression analysis were performed to identify key genes and pathogenic pattern during the progression of PF. MiRanda, miRcode, and TargetScan were utilized to predict target relationships in the potential competing endogenous RNA (ceRNA) network. The results were verified by qRT-PCR analysis. In the context of BLM-induced PF, this study identified a total of 167 differentially expressed messenger RNAs (DEmRNAs), 115 differentially expressed long non-coding RNAs (DElncRNAs), 45 differentially expressed circular RNAs (DEcircRNAs), and 87 differentially expressed microRNAs (DEmiRNAs). These RNA molecules showed dynamic alterations in response to BLM-induced PF. These DEmRNAs exhibited a predominant association with the biological processes pertaining to the organization of extracellular matrix. A regulatory network was built in PF, encompassing 31 DEmRNAs, 18 DE lncRNAs, 13 DEcircRNAs, and 13 DEmiRNAs. Several DERNA molecules were subjected to validate using additional BLM-induced PF model. The outcomes of this validation process shown a strong correlation with the results obtained from RNA sequencing analysis. The GSE213001 dataset was utilized to validate the expression levels and diagnostic efficacy of four specific hub mRNAs (CCDC80, CLU, COL5A1, and COL6A3) in individuals diagnosed with PF. In this study, we identified and validated several RNA molecules that exhibited dynamic alternations in response to BLM-induced PF. These dysregulated RNAs participated in the pathogenesis of PF and can be used as therapeutic targets for early-stage IPF. Although more work must be done to confirm the results, our study may provide directions for future studies.

Loss of SETD2 aggravates colorectal cancer progression caused by SMAD4 deletion through the RAS/ERK signalling pathway

BACKGOUND

Colorectal cancer (CRC) is a complex, multistep disease that arises from the interplay genetic mutations and epigenetic alterations. The histone H3K36 trimethyltransferase SET domain-containing 2 (SETD2), as an epigenetic signalling molecule, has a 5% mutation rate in CRC. SETD2 expression is decreased in the development of human CRC and mice treated with Azoxymethane /Dextran sodium sulfate (AOM/DSS). Loss of SETD2 promoted CRC development. SMAD Family member 4 (SMAD4) has a 14% mutation rate in CRC, and SMAD4 ablation leads to CRC. The co-mutation of SETD2 and SMAD4 predicted advanced CRC. However, little is known on the potential synergistic effect of SETD2 and SMAD4.

METHODS

CRC tissues from mice and SW620 cells were used as research subjects. Clinical databases of CRC patients were analyzed to investigate the association between SETD2 and SMAD4. SETD2 and SMAD4 double-knockout mice were established to further investigate the role of SETD2 in SMAD4-deficient CRC. The intestinal epithelial cells (IECs) were isolated for RNA sequencing and chromatin immunoprecipitation sequencing (ChIP-seq) to explore the mechanism and the key molecules resulting in CRC. Molecular and cellular experiments were conducted to analyze the role of SETD2 in SMAD4-deficient CRC. Finally, rescue experiments were performed to confirm the molecular mechanism of SETD2 in the development of SMAD4-dificient CRC.

RESULTS

The deletion of SETD2 promotes the malignant progression of SMAD4-deficient CRC. Smad4Vil-KO ; Setd2Vil-KO mice developed a more severe CRC phenotype after AOM/DSS induction, with a larger tumour size and a more vigorous epithelial proliferation rate. Further mechanistic findings revealed that the loss of SETD2 resulted in the down-regulation of DUSP7, which is involved in the inhibition of the RAS/ERK signalling pathway. Finally, the ERK1/2 inhibitor SCH772984 significantly attenuated the progression of CRC in Smad4Vil-KO ;Setd2Vil-KO mice, and overexpression of DUSP7 significantly inhibited the proliferation rates of SETD2KO ; SMAD4KO SW620 cells.

CONCLUSIONS

Our results demonstrated that SETD2 inhibits the RAS/ERK signaling pathway by facilitating the transcription of DUSP7 in SMAD4-deficient CRC, which could provide a potential therapeutic target for the treatment of advanced CRC.

Inflammatory Cytokine Elaboration Following Secondhand Smoke (SHS) Exposure Is Mediated in Part by RAGE Signaling

The receptor for advanced glycation end products (RAGE) is a key contributor to immune and inflammatory responses in myriad diseases. RAGE is a transmembrane pattern recognition receptor with a special interest in pulmonary anomalies due to its naturally abundant pulmonary expression. Our previous studies demonstrated an inflammatory role for RAGE following acute 30-day exposure to secondhand smoke (SHS), wherein immune cell diapedesis and cytokine/chemokine secretion were accentuated in part via RAGE signaling. However, the chronic inflammatory mechanisms associated with RAGE have yet to be fully elucidated. In this study, we address the impact of long-term SHS exposure on RAGE signaling. RAGE knockout (RKO) and wild-type (WT) mice were exposed to SHS using a nose-only delivery system (Scireq Scientific, Montreal, Canada) for six months. SHS-exposed animals were compared to mice exposed to room air (RA) only. Immunoblotting was used to assess the phospho-AKT and phospho-ERK activation data, and colorimetric high-throughput assays were used to measure NF-kB. Ras activation was measured via ELISAs. Bronchoalveolar lavage fluid (BALF) cellularity was quantified, and a mouse cytokine antibody array was used to screen the secreted cytokines. The phospho-AKT level was decreased, while those of phospho-ERK, NF-kB, and Ras were elevated in both groups of SHS-exposed mice, with the RKO + SHS-exposed mice demonstrating significantly decreased levels of each intermediate compared to those of the WT + SHS-exposed mice. The BALF contained increased levels of diverse pro-inflammatory cytokines in the SHS-exposed WT mice, and diminished secretion was detected in the SHS-exposed RKO mice. These results validate the role for RAGE in the mediation of chronic pulmonary inflammatory responses and suggest ERK signaling as a likely pathway that perpetuates RAGE-dependent inflammation. Additional characterization of RAGE-mediated pulmonary responses to prolonged exposure will provide a valuable insight into the cellular mechanisms of lung diseases such as chronic obstructive pulmonary disease.

Voluntary wheel-running improved pulmonary fibrosis by reducing epithelial mesenchymal transformation

AIMS

Pulmonary fibrosis seriously affects the health and life quality of patients. Exercise has been shown to have anti-inflammatory and antioxidant effects, but its effect on pulmonary fibrosis is unclear. In this study, the effect and mechanism of exercise on pulmonary fibrosis induced by paraquat were detected.

MAIN METHODS

Three data sets were retrieved from GEO data. The biological significance of DEGs generation was determined by GO, KEGG, GSEA, and PPI. Thirty male BALB/C mice were randomly divided into control group, model group and exercise group. H&E staining, Masson staining, Immunohistochemistry and Western blot were used to explore the results. The levels of SOD, CAT, MDA, and GSH in lung tissue were analyzed with detection kits. The levels of inflammatory factors in serum and BALF were measured by ELISA.

KEY FINDINGS

Compared with the control group, the infiltration of inflammatory cells and fibrotic lesions were increased in the model group. Compared with the model group, voluntary wheel-running reducing the EMT of alveolar epithelial cells, the activation of the Wnt/β-catenin signaling pathway and the level of oxidative distress. Moreover, compared to model group, the serum IL-4, IL-10 and IFN-γ were increased, while the serum CXCL1 were decreased, while the levels of CXCL1, IL-6, IL-10, TNF-α and IFN-γ in the bronchoalveolar lavage fluid were decreased in exercise group.

SIGNIFICANCE

Voluntary wheel-running reduced inflammatory infiltration and upregulated the expression of antioxidative distress proteins, further to improve the degree of EMT, and ultimately alleviated paraquat induced pulmonary fibrosis.

Increased expression of OPN contributes to idiopathic pulmonary fibrosis and indicates a poor prognosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is fibrotic lung disease with no effective treatment. It is characterized by destruction of alveolar structure and pulmonary interstitial fibrosis, leading to dyspnea and even asphyxia death of patients. Epithelial-mesenchymal transition (EMT) is considered to be a driving factor in the pathogenesis of IPF. Osteopontin (OPN) is a secreted protein widely present in the extracellular matrix and involved in the occurrence and development of a variety of diseases.

METHODS

The original datasets were obtained from NCBI GEO databases analyzed with the online tool GEO2R and EasyGEO. Bleomycin induced mouse pulmonary fibrosis model and OPN/OPN-biotin treated mouse model were established to investigate the role of OPN in mouse pulmonary fibrosis and the target cells of OPN. A549 cells and HBE cells were used to explore the mechanism of OPN-induced epithelial-mesenchymal transition (EMT) in epithelial cells and mass spectrometry was used to detect OPN downstream receptors. Precision-cut lung slices and lentivirus-treated mice with pulmonary fibrosis were used to examine the therapeutic effect of OPN and its downstream pathways on pulmonary fibrosis.

RESULTS

We demonstrate that the content of OPN in IPF bronchoalveolar lavage fluid (BALF) is high compared to the normal groups, and its expression level is correlated with prognosis. At the animal level, OPN was highly expressed at all stages of pulmonary fibrosis in mice, and the bronchoalveolar lavage fluid (BALF) could accurately reflect its expression in the lung. Next, we reveal that OPN was mainly expressed by macrophages and the main target cells of OPN were epithelial cells. Mice developed pulmonary fibrosis accompanied after treating the mice with OPN. Both in vitro and in vivo experiments confirmed that OPN could induce EMT of alveolar epithelial cells. Mechanistically, OPN binding triggered phosphorylation of FAK by CD44, thus activating snail1-mediated profibrotic protein synthesis. Inhibition of FAK phosphorylation and its downstream pathways can effectively alleviate pulmonary fibrosis in precision sections of lung tissue (PCLS) assay. OPN knockdown in bleomycin-induced lung fibrosis mice led to significantly less fibrosis.

CONCLUSION

Our data suggest that OPN mediates lung fibrosis through EMT, implicating its potential therapeutic target and prognostic indicator role for IPF. OPN may be a target for the diagnosis and treatment of IPF.

What role does PDL1 play in EMT changes in tumors and fibrosis?

Epithelial-mesenchymal transformation (EMT) plays a pivotal role in embryonic development, tissue fibrosis, repair, and tumor invasiveness. Emerging studies have highlighted the close association between EMT and immune checkpoint molecules, particularly programmed cell death ligand 1 (PDL1). PDL1 exerts its influence on EMT through bidirectional regulation. EMT-associated factors, such as YB1, enhance PDL1 expression by directly binding to its promoter. Conversely, PDL1 signaling triggers downstream pathways like PI3K/AKT and MAPK, promoting EMT and facilitating cancer cell migration and invasion. Targeting PDL1 holds promise as a therapeutic strategy for EMT-related diseases, including cancer and fibrosis. Indeed, PDL1 inhibitors, such as pembrolizumab and nivolumab, have shown promising results in clinical trials for various cancers. Recent research has also indicated their potential benefit in fibrosis treatment in reducing fibroblast activation and extracellular matrix deposition, thereby addressing fibrosis. In this review, we examine the multifaceted role of PDL1 in immunomodulation, growth, and fibrosis promotion. We discuss the challenges, mechanisms, and clinical observations related to PDL1, including the limitations of the PD1/PDL1 axis in treatment and PD1-independent intrinsic PDL1 signaling. Our study highlights the dynamic changes in PDL1 expression during the EMT process across various tumor types. Through interplay between PDL1 and EMT, we uncover co-directional alterations, regulatory pathways, and diverse changes resulting from PDL1 intervention in oncology. Additionally, our findings emphasize the dual role of PDL1 in promoting fibrosis and modulating immune responses across multiple diseases, with potential implications for therapeutic approaches. We particularly investigate the therapeutic potential of targeting PDL1 in type II EMT fibrosis: strike balance between fibrosis modulation and immune response regulation. This analysis provides valuable insights into the multifaceted functions of PDL1 and contributes to our understanding of its complex mechanisms and therapeutic implications.

Relaxin-Loaded Inhaled Porous Microspheres Inhibit Idiopathic Pulmonary Fibrosis and Improve Pulmonary Function Post-Bleomycin Challenges

Idiopathic pulmonary fibrosis (IPF) causes worsening pulmonary function, and no effective treatment for the disease etiology is available now. Recombinant Human Relaxin-2 (RLX), a peptide agent with anti-remodeling and anti-fibrotic effects, is a promising biotherapeutic candidate for musculoskeletal fibrosis. However, due to its short circulating half-life, optimal efficacy requires continuous infusion or repeated injections. Here, we developed the porous microspheres loading RLX (RLX@PMs) and evaluated their therapeutic potential on IPF by aerosol inhalation. RLX@PMs have a large geometric diameter as RLX reservoirs for a long-term drug release, but smaller aerodynamic diameter due to their porous structures, which were beneficial for higher deposition in the deeper lungs. The results showed a prolonged release over 24 days, and the released drug maintained its peptide structure and activity. RLX@PMs protected mice from excessive collagen deposition, architectural distortion, and decreased compliance after a single inhalation administration in the bleomycin-induced pulmonary fibrosis model. Moreover, RLX@PMs showed better safety than frequent gavage administration of pirfenidone. We also found RLX-ameliorated human myofibroblast-induced collagen gel contraction and suppressed macrophage polarization to the M2 type, which may be the reason for reversing fibrosis. Hence, RLX@PMs represent a novel strategy for the treatment of IPF and suggest clinical translational potential.

Distribution and chemotactic mechanism of CD4+ T cells in traumatic tracheal stenosis

A systemic and local inflammatory immune imbalance is thought to be the cause of traumatic tracheal stenosis (TS). However, with CD4+ T lymphocytes being the predominant immune cells in TS, the mechanism of action and recruitment has not been described. In our research, using flow cytometry, ELISA, immunofluorescence, and Transwell chamber assays, the expression, distribution, and potential chemotactic function of CD4+ T cells in TS patients were examined before and after treatment. The results showed that the untreated group had significantly more CD4+ T cells and their secreted TGF-β1 than the treated group. Additionally, the untreated group's CD4+ T cells showed a significant rise in CCL22 and CCL1, as well as a larger proportion of CCR4 and CCR8. CD4+ T cells and CD68+ macrophages located in TS also expressed CCL1 and CCL22. In vitro, anti-CCL1 and anti-CCL22 can partially block the chemoattractant effect of TS bronchoalveolar lavage (BAL) on purified CD4+ T cells. The findings of this study indicated that TS contained unbalanced CD4 immune cells that were actively recruited locally by CCR4/CCL22 and CCR8/CCL1. As a result, it is anticipated that CD4 immune rebalancing can serve as a novel treatment for TS.

PRDX1 negatively regulates bleomycin-induced pulmonary fibrosis via inhibiting the epithelial-mesenchymal transition and lung fibroblast proliferation in vitro and in vivo

BACKGROUND

Pulmonary fibrosis is a major category of end-stage changes in lung diseases, characterized by lung epithelial cell damage, proliferation of fibroblasts, and accumulation of extracellular matrix. Peroxiredoxin 1 (PRDX1), a member of the peroxiredoxin protein family, participates in the regulation of the levels of reactive oxygen species in cells and various other physiological activities, as well as the occurrence and development of diseases by functioning as a chaperonin.

METHODS

Experimental methods including MTT assay, morphological observation of fibrosis, wound healing assay, fluorescence microscopy, flow cytometry, ELISA, western blot, transcriptome sequencing, and histopathological analysis were used in this study.

RESULTS

PRDX1 knockdown increased ROS levels in lung epithelial cells and promoted epithelial-mesenchymal transition (EMT) through the PI3K/Akt and JNK/Smad signalling pathways. PRDX1 knockout significantly increased TGF-β secretion, ROS production, and cell migration in primary lung fibroblasts. PRDX1 deficiency also increased cell proliferation, cell cycle circulation, and fibrosis progression through the PI3K/Akt and JNK/Smad signalling pathways. BLM treatment induced more severe pulmonary fibrosis in PRDX1-knockout mice, mainly through the PI3K/Akt and JNK/Smad signalling pathways.

CONCLUSIONS

Our findings strongly suggest that PRDX1 is a key molecule in BLM-induced lung fibrosis progression and acts through modulating EMT and lung fibroblast proliferation; therefore, it may be a therapeutic target for the treatment of BLM-induced lung fibrosis.

The chemokine CCL1 facilitates pulmonary fibrosis by promoting macrophage migration and M2 polarization

Macrophage M2 polarization has been identified in the pathogenesis of pulmonary fibrosis (PF), but the mediators that drive the macrophage M2 program in PF need to be clarified. We showed that the expression of AMFR and CCR8, two known receptors of CCL1, was increased in macrophages from lungs of mice with bleomycin (BLM)-induced PF. Deficiency in either AMFR or CCR8 in macrophages protected mice from BLM-induced PF. In vitro experiments revealed that CCL1 recruited macrophages by binding to its classical receptor CCR8 and drove the macrophage M2 phenotype via its interaction with the recently identified receptor AMFR. Mechanistic studies revealed that the CCL1-AMFR interaction enhanced CREB/C/EBPβ signaling to promote the macrophage M2 program. Together, our findings reveal that CCL1 acts as a mediator of macrophage M2 polarization and could be a therapeutic target in PF.

Transcription factor Dmrt1 triggers the SPRY1-NF-κB pathway to maintain testicular immune homeostasis and male fertility

Bacterial or viral infections, such as Brucella, mumps virus, herpes simplex virus, and Zika virus, destroy immune homeostasis of the testes, leading to spermatogenesis disorder and infertility. Of note, recent research shows that SARS-CoV-2 can infect male gonads and destroy Sertoli and Leydig cells, leading to male reproductive dysfunction. Due to the many side effects associated with antibiotic therapy, finding alternative treatments for inflammatory injury remains critical. Here, we found that Dmrt1 plays an important role in regulating testicular immune homeostasis. Knockdown of Dmrt1 in male mice inhibited spermatogenesis with a broad inflammatory response in seminiferous tubules and led to the loss of spermatogenic epithelial cells. Chromatin immunoprecipitation sequencing (ChIP-seq) and RNA sequencing (RNA-seq) revealed that Dmrt1 positively regulated the expression of Spry1, an inhibitory protein of the receptor tyrosine kinase (RTK) signaling pathway. Furthermore, immunoprecipitation-mass spectrometry (IP-MS) and co-immunoprecipitation (Co-IP) analysis indicated that SPRY1 binds to nuclear factor kappa B1 (NF-κB1) to prevent nuclear translocation of p65, inhibit activation of NF-κB signaling, prevent excessive inflammatory reaction in the testis, and protect the integrity of the blood-testis barrier. In view of this newly identified Dmrt1- Spry1-NF-κB axis mechanism in the regulation of testicular immune homeostasis, our study opens new avenues for the prevention and treatment of male reproductive diseases in humans and livestock.

The alcohol extracts of Sceptridium ternatum (Thunb.) Lyon exert anti-pulmonary fibrosis effect through targeting SETDB1/STAT3/p-STAT3 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Pulmonary fibrosis (PF) is a pathological process of irreversible scarring of lung tissues, with limited treatment means. Sceptridium ternatum (Thunb.) Lyon (STE) is a traditional Chinese herbal medicine that has a traditional use in relieving cough and asthma, resolving phlegm, clearing heat, and detoxicating in China. However, its role in PF has not been reported.

AIM OF THE STUDY

This study aims to investigate the protective role of STE in PF and the underlying mechanisms.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats were divided into control group, PF model group, positive drug (pirfenidone) group and STE group. After 28 days of STE administration in bleomycin (BLM)-induced PF rats, living Nuclear Magnetic Resonance Imaging (NMRI) was used to observe the structural changes of lung tissues. H&E and Masson's trichrome staining were used to observe PF-associated pathological alteration, and immunohistochemistry (IHC) staining, western blotting, and qRT-PCR were used to detect the expression of PF-related marker proteins in the lung tissues. ELISA was used to detect PF-associated biochemical criteria in the lung tissue homogenates. The proteomics technology was used to screen the different proteins. Co-immunoprecipitation, western blotting, and IHC staining were used to confirm the underlying targets of STE as well as its downstream signaling. UPLC-Triple-TOF/MS assay was used to explore the effective components in the alcohol extracts of STE. Autodock vina was used to detect the potential binding between the above effective components and SETDB1.

RESULTS

STE prevented PF by inhibiting the activation of lung fibroblasts and ECM deposition in BLM-induced PF rats. Mechanism analyses demonstrated that STE could inhibit the up-regulation of SETDB1 induced by BLM and TGF-β1, which further blocked the binding of SETDB1 and STAT3 as well as the phosphorylation of STAT3, ultimately preventing the activation and proliferation of lung fibroblasts.

CONCLUSION

STE played a preventive role in PF by targeting the SETBD1/STAT3/p-STAT3 pathway, which may be a potential therapeutic agent for PF.

CCL17 drives fibroblast activation in the progression of pulmonary fibrosis by enhancing the TGF-β/Smad signaling

Pulmonary fibrosis (PF) is a type of fatal respiratory diseases with limited therapeutic options and poor prognosis. The chemokine CCL17 plays crucial roles in the pathogenesis of immune diseases. Bronchoalveolar lavage fluid (BALF) CCL17 levels are significantly higher in patients with idiopathic PF (IPF) than in healthy volunteers. However, the source and function of CCL17 in PF remain unclear. Here, we demonstrated that the levels of CCL17 were increased in the lungs of IPF patients and mice with bleomycin (BLM)-induced PF. In particular, CCL17 were upregulated in alveolar macrophages (AMs) and antibody blockade of CCL17 protected mice against BLM-induced fibrosis and significantly reduced fibroblast activation. Mechanistic studies revealed that CCL17 interacted with its receptor CCR4 on fibroblasts, thereby activating the TGF-β/Smad signaling pathway to promote fibroblast activation and tissue fibrosis. Moreover, the knockdown of CCR4 by CCR4-siRNA or blockade by CCR4 antagonist C-021 was able to ameliorate PF pathology in mice. In summary, the CCL17-CCR4 axis is involved in the progression of PF, and targeting of CCL17 or CCR4 inhibits fibroblast activation and tissue fibrosis and may benefit patients with fibroproliferative lung diseases.

Evaluation of an ex vivo fibrogenesis model using human lung slices prepared from small tissues

BACKGROUND

In recent years, there have been breakthroughs in the preclinical research of respiratory diseases, such as organoids and organ tissue chip models, but they still cannot provide insight into human respiratory diseases well. Human lung slices model provides a promising in vitro model for the study of respiratory diseases because of its preservation of lung structure and major cell types.

METHODS

Human lung slices were manually prepared from small pieces of lung tissues obtained from lung cancer patients subjected to lung surgery. To evaluate the suitability of this model for lung fibrosis research, lung slices were treated with CdCl₂ (30 μM), TGF-β1 (1 ng/ml) or CdCl₂ plus TGF-β1 for 3 days followed by toxicity assessment, gene expression analysis and histopathological observations.

RESULTS

CdCl₂ treatment resulted in a concentration-dependent toxicity profile evidenced by MTT assay as well as histopathological observations. In comparison with the untreated group, CdCl₂ and TGF-β1 significantly induces MMP2 and MMP9 gene expression but not MMP1. Interestingly, CdCl₂ plus TGF-β1 significantly induces the expression of MMP1 but not MMP2, MMP7 or MMP9. Microscopic observations reveal the pathogenesis of interstitial lung fibrosis in the lung slices of all groups; however, CdCl₂ plus TGF-β1 treatment leads to a greater alveolar septa thickness and the formation of fibroblast foci-like pathological features. The lung slice model is in short of blood supply and the inflammatory/immune-responses are considered minimal.

CONCLUSIONS

The results are in favor of the hypothesis that idiopathic pulmonary fibrosis (IPF) is mediated by tissue damage and abnormal repair. Induction of MMP1 gene expression and fibroblast foci-like pathogenesis suggest that this model might represent an early stage of IPF.

CC chemokines family in fibrosis and aging: From mechanisms to therapy

Fibrosis is a universal aging-related pathological process in the different organ, but is actually a self-repair excessive response. To date, it still remains a large unmet therapeutic need to restore injured tissue architecture without detrimental side effects, due to the limited clinical success in the treatment of fibrotic disease. Although specific organ fibrosis and the associated triggers have distinct pathophysiological and clinical manifestations, they often share involved cascades and common traits, including inflammatory stimuli, endothelial cell injury, and macrophage recruitment. These pathological processes can be widely controlled by a kind of cytokines, namely chemokines. Chemokines act as a potent chemoattractant to regulate cell trafficking, angiogenesis, and extracellular matrix (ECM). Based on the position and number of N-terminal cysteine residues, chemokines are divided into four groups: the CXC group, the CX3C group, the (X)C group, and the CC group. The CC chemokine classes (28 members) is the most numerous and diverse subfamily of the four chemokine groups. In this Review, we summarized the latest advances in the understanding of the importance of CC chemokine in the pathogenesis of fibrosis and aging and discussed potential clinical therapeutic strategies and perspectives aimed at resolving excessive scarring formation.

CC Chemokines in Idiopathic Pulmonary Fibrosis: Pathogenic Role and Therapeutic Potential

Idiopathic pulmonary fibrosis (IPF), characterized by progressive worsening of dyspnea and irreversible decline in lung function, is a chronic and progressive respiratory disease with a poor prognosis. Chronic or repeated lung injury results in inflammation and an excessive injury-repairing response that drives the development of IPF. A number of studies have shown that the development and progression of IPF are associated with dysregulated expression of several chemokines and chemokine receptors, several of which have been used as predictors of IPF outcome. Chemokines of the CC family play significant roles in exacerbating IPF progression by immune cell attraction or fibroblast activation. Modulating levels of detrimental CC chemokines and interrupting the corresponding transduction axis by neutralizing antibodies or antagonists are potential treatment options for IPF. Here, we review the roles of different CC chemokines in the pathogenesis of IPF, and their potential use as biomarkers or therapeutic targets.

Neutrophil extracellular traps and pulmonary fibrosis: an update

Pulmonary fibrosis (PF) is a serious and often fatal illness that occurs in various clinical settings and represents a significant unmet medical need. Increasing evidence indicates that neutrophil extracellular traps (NETs) contribute significantly to the progression of PF. Therefore, understanding the pathways by which NETs contribute to the disease is crucial for developing effective treatments. This review focuses on the formation of NETs and the common mechanisms of NETs in PF.

Identification and validation of chemokine system-related genes in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with limited therapeutic options. Recent studies have demonstrated that chemokines play a vital role in IPF pathogenesis. In the present study, we explored whether the gene signature associated with chemokines could be used as a reliable biological marker for patients with IPF.

Methods

Chemokine-related differentially expressed genes (CR-DEGs) in IPF and control lung tissue samples were identified using data from the Gene Expression Omnibus database. A chemokine-related signature of the diagnostic model was established using the LASSO-Cox regression. In addition, unsupervised cluster analysis was conducted using consensus-clustering algorithms. The CIBERSORT algorithm was used to calculate immune cell infiltration across patient subgroups. Finally, we established a mouse model of bleomycin-induced pulmonary fibrosis and a model of fibroblasts treated with TGFβ1. Expression levels of chemokine-related signature genes were determined using real-time quantitative polymerase chain reaction (RT-qPCR).

Results

We established a chemokine-related eleven-gene signature of a diagnostic model consisting of CXCL2, CCRL2, ARRB1, XCL1, GRK5, PPBP, CCL19, CCL13, CCL11, CXCL6, and CXCL13, which could easily distinguish between IPF patients and controls. Additionally, we identified two subtypes of IPF samples based on chemokine-related gene expression. Pulmonary function parameters and stromal scores were significantly higher in subtype 1 than in subtype 2. Several immune cell types, especially plasma cells and macrophages, differ significantly between the two subtypes. RT-qPCR results showed that the expression levels of Cxcl2 and Ccl2 increased considerably in bleomycin-induced mice. Meanwhile, Arrb1, Ccrl2, Grk5, and Ppbp expression was significantly reduced. Furthermore, multiple chemokine-related genes were altered in TGFβ1 or TNFα-induced fibroblast cells.

Conclusions

A novel chemokine-related eleven-signature of diagnostic model was developed. These genes are potential biomarkers of IPF and may play essential roles in its pathogenesis.

Enhanced MCM5 Level Predicts Bad Prognosis in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a fatal heterogeneous hematologic malignancy. There is an urgent need to identify potential biomarkers to better classify sufferers with bad outcomes that might need more advanced treatment. The objective of this study was to investigate prognostic indicators that predict the outcome of sufferers with AML. The datasets of AML sufferers including mRNA sequencing data and clinical information were acquired from GEO datasets (GSE38865) and TCGA datasets. Kaplan–Meier curves and Cox regression analysis to screen genes correlated to survival. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses biological process analysis were utilized in verifying the function of various genes. Sufferers with elevated MCM5 level exhibited a worse prognosis, according to the survival analysis. It was indicated through multivariate and univariate analysis that MCM5 level was an independent adverse prognostic element for over survival in AML sufferers based on GEO and TCGA datasets. Meanwhile, MCM5 level in AML samples was higher than in normal samples. Additionally, it was indicated through PPI network and functional enrichment analyses that through accelerating cell cycle and DNA replication, MCM5 promoted AML progression. In conclusions, MCM5 level was an independent poor prognostic element in AML sufferers based on GEO and TCGA datasets. This is the first time that MCM5 is reported to be a biomarker of poor prognosis in AML.

The role of PD-1/PD-L1 axis in idiopathic pulmonary fibrosis: Friend or foe?

Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease with a bleak prognosis. Mounting evidence suggests that IPF shares bio-molecular similarities with lung cancer. Given the deep understanding of the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway in cancer immunity and the successful application of immune checkpoint inhibitors (ICIs) in lung cancer, recent studies have noticed the role of the PD-1/PD-L1 axis in IPF. However, the conclusions are ambiguous, and the latent mechanisms remain unclear. In this review, we will summarize the role of the PD-1/PD-L1 axis in IPF based on current murine models and clinical studies. We found that the PD-1/PD-L1 pathway plays a more predominant profibrotic role than its immunomodulatory role in IPF by interacting with multiple cell types and pathways. Most preclinical studies also indicated that blockade of the PD-1/PD-L1 pathway could attenuate the severity of pulmonary fibrosis in mice models. This review will bring significant insights into understanding the role of the PD-1/PD-L1 pathway in IPF and identifying new therapeutic targets.

Role of Mesenchymal Stem Cells and Extracellular Vesicles in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial fibrotic disease that leads to disability and death within 5 years of diagnosis. Pulmonary fibrosis is a disease with a multifactorial etiology. The concept of aberrant regeneration of the pulmonary epithelium reveals the pathogenesis of IPF, according to which repeated damage and death of alveolar epithelial cells is the main mechanism leading to the development of progressive IPF. Cell death provokes the migration, proliferation and activation of fibroblasts, which overproduce extracellular matrix, resulting in fibrotic deformity of the lung tissue. Mesenchymal stem cells (MSCs) and extracellular vesicles (EVs) are promising therapies for pulmonary fibrosis. MSCs, and EVs derived from MSCs, modulate the activity of immune cells, inhibit the expression of profibrotic genes, reduce collagen deposition and promote the repair of damaged lung tissue. This review considers the molecular mechanisms of the development of IPF and the multifaceted role of MSCs in the therapy of IPF. Currently, EVs-MSCs are regarded as a promising cell-free therapy tool, so in this review we discuss the results available to date of the use of EVs-MSCs for lung tissue repair.

Macrophage derived miR-7219-3p-containing exosomes mediate fibroblast trans-differentiation by targeting SPRY1 in silicosis

Silicosis is one of the most serious occupational diseases with the main feature of inflammatory cell infiltration, fibroblasts activation, and large deposition of extracellular matrix in the lung. Increasing evidence indicates that macrophage-derived exosomes may play an important role in the development of silicosis by transferring their loaded microRNAs (miRNAs). Hence we carried out high-throughput sequencing to identify the expression of exosomal miRNA from macrophages exposed to silica or not in the previous study. Then we verified that miR-7219-3p was significantly up-regulated in macrophages and their exosomes after silica-exposure, as well as in the silicotic mice model by qRT-PCR, subsequent experiments confirmed that the increase of miR-7219-3p facilitated fibroblast to myofibroblast trans-differentiation (FMT), as well as cell proliferation and migration. Spouty1 (SPRY1), which served as a negative modulator of the Ras/ERK/MAPK signaling pathway, was verified as the target gene of miR-7219-3p, the knockdown or over-expression of SPRY1 apparently promoted or inhibited FMT via the Ras/ERK/MAPK signaling pathway. Furthermore, the inhibition of exosomal miR-7219-3p partially suppressed FMT and silica-induced pulmonary fibrosis in vitro and in vivo. In brief, our results demonstrated that exosomal miR-7219-3p played an important role in FMT and might be a novel therapeutic target of silicosis.

The Role of Nrf2 in Pulmonary Fibrosis: Molecular Mechanisms and Treatment Approaches

Pulmonary fibrosis is a chronic, progressive, incurable interstitial lung disease with high mortality after diagnosis and remains a global public health problem. Despite advances and breakthroughs in understanding the pathogenesis of pulmonary fibrosis, there are still no effective methods for the prevention and treatment of pulmonary fibrosis. The existing treatment options are imperfect, expensive, and have considerable limitations in effectiveness and safety. Hence, there is an urgent need to find novel therapeutic targets. The nuclear factor erythroid 2-related factor 2 (Nrf2) is a central regulator of cellular antioxidative responses, inflammation, and restoration of redox balance. Accumulating reports reveal that Nrf2 activators exhibit potent antifibrosis effects and significantly attenuate pulmonary fibrosis in vivo and in vitro. This review summarizes the current Nrf2-related knowledge about the regulatory mechanism and potential therapies in the process of pulmonary fibrosis. Nrf2 orchestrates the activation of multiple protective genes that target inflammation, oxidative stress, fibroblast–myofibroblast differentiation (FMD), and epithelial–mesenchymal transition (EMT), and the mechanisms involve Nrf2 and its downstream antioxidant, Nrf2/HO−1/NQO1, Nrf2/NOX4, and Nrf2/GSH signaling pathway. We hope to indicate potential for Nrf2 system as a therapeutic target for pulmonary fibrosis.

Integrated analysis of single-cell and bulk RNA sequencing reveals pro-fibrotic PLA2G7high macrophages in pulmonary fibrosis

Pulmonary fibrosis (PF) is the pathological change of end-stage interstitial lung diseases with high mortality and limited therapeutic options. Lung macrophages have distinct subsets with divergent functions, and play critical roles in the pathogenesis of PF. In this study, integrative analysis of lung single-cell and bulk RNA-seq data from patients with fibrotic hypersensitivity pneumonitis and idiopathic pulmonary fibrosis was utilized to identify particular macrophage subsets during the development of PF. We find a specific macrophage subpopulation highly expressing PLA2G7 in fibrotic lungs. We performed additional single-cell RNA-seq analysis to identify analogous macrophage population in bleomycin (BLM)-induced mouse pulmonary fibrosis models. By in vitro and in vivo experiments, we further reveal the pro-fibrotic role for this PLA2G7^high macrophage subset in fibroblast-to-myofibroblast transition (FMT) during pulmonary fibrosis. PLA2G7 promotes FMT via LPC/ATX/LPA/LPA2 axis in macrophages. Moreover, PLA2G7 is regulated by STAT1, and pharmacological inhibition of PLA2G7 by Darapladib ameliorates pulmonary fibrosis in BLM-induced mice. The results of this study support the view that PLA2G7^high macrophage subpopulation contributes importantly to the pathogenesis of PF, which provides a potential way for targeted therapy.

Role of chemokine systems in cancer and inflammatory diseases

Chemokines are a large family of small secreted proteins that have fundamental roles in organ development, normal physiology, and immune responses upon binding to their corresponding receptors. The primary functions of chemokines are to coordinate and recruit immune cells to and from tissues and to participate in regulating interactions between immune cells. In addition to the generally recognized antimicrobial immunity, the chemokine/chemokine receptor axis also exerts a tumorigenic function in many different cancer models and is involved in the formation of immunosuppressive and protective tumor microenvironment (TME), making them potential prognostic markers for various hematologic and solid tumors. In fact, apart from its vital role in tumors, almost all inflammatory diseases involve chemokines and their receptors in one way or another. Modulating the expression of chemokines and/or their corresponding receptors on tumor cells or immune cells provides the basis for the exploitation of new drugs for clinical evaluation in the treatment of related diseases. Here, we summarize recent advances of chemokine systems in protumor and antitumor immune responses and discuss the prevailing understanding of how the chemokine system operates in inflammatory diseases. In this review, we also emphatically highlight the complexity of the chemokine system and explore its potential to guide the treatment of cancer and inflammatory diseases.

TRAF6 Suppresses the Development of Pulmonary Fibrosis by Attenuating the Activation of Fibroblasts

Pulmonary fibrosis (PF) has a high mortality rate, and its pathogenesis is unknown. TNF receptor-associated factor 6 (TRAF6), a signal transducer for inflammatory signaling, plays crucial roles in the pathogenesis of immune diseases. However, its function in PF remains unknown. Herein, we demonstrated that lungs from mice with bleomycin (BLM)-induced PF were characterized by decreased expression of TRAF6 in lung fibroblasts. Enhancing TRAF6 expression protected mice from BLM-induced PF coupled with a significant reduction in fibroblast differentiation. Furthermore, we demonstrated that overexpression of TRAF6 reversed the activation of myofibroblasts from PF mice by reducing the expression of Wnt3a and subsequently suppressing Wnt/β-catenin signaling. Additionally, the abundance of Tribbles pseudokinase 3 (TRIB3), a stress sensor, was negatively correlated with the abundance of TRAF6 in lung fibroblasts. TRIB3 overexpression decreased TRAF6 abundance by reducing TRAF6 stability in lung fibroblasts during PF. Mechanistic studies revealed that TRIB3 bound to TRAF6 and accelerated basal TRAF6 ubiquitination and degradation. Collectively, our data indicate that reduced TRAF6 expression in fibroblasts is essential for the progression of PF, and therefore, genetically increasing TRAF6 expression or disrupting the TRIB3-TRAF6 interaction could be potential therapeutic strategies for fibroproliferative lung diseases in clinical settings.

AMFR drives allergic asthma development by promoting alveolar macrophage-derived GM-CSF production

Alveolar macrophages (AMs) are specialized tissue-resident macrophages that orchestrate the immune response in allergic inflammation and asthma. However, what signals direct AMs to cross talk with other immune cells remains unclear. Here, we report that autocrine motility factor receptor (AMFR), an endoplasmic reticulum-resident E3 ubiquitin ligase, is upregulated in AMs of asthma and is critical for this condition. AMFR deficiency significantly decreased allergy-induced T helper 2 (Th2) and eosinophilic inflammation, with less granulocyte-macrophage colony-stimulating factor (GM-CSF) production in AMs. Mechanistically, following thymic stromal lymphopoietin (TSLP) stimulation, AMFR associated directly with cytokine-inducible SH2-containing protein (CIS), induced the ubiquitination of Lys48-linked polyubiquitination of CIS, and consequently blocked the inhibitory effect of CIS on signal transducer and activator of transcription 5 (STAT5) phosphorylation and the downstream pathway activation in AMs. In conclusion, our results demonstrate that AMFR serves a crucial role in promoting inflammation in asthma through regulating AM function, and may emerge as a new potential drug target for asthma therapy.

Anti-Inflammatory and Anti-Fibrotic Effect of Immortalized Mesenchymal-Stem-Cell-Derived Conditioned Medium on Human Lung Myofibroblasts and Epithelial Cells

Idiopathic pulmonary fibrosis (IPF) is caused by progressive lung tissue impairment due to extended chronic fibrosis, and it has no known effective treatment. The use of conditioned media (CM) from an immortalized human adipose mesenchymal stem cell line could be a promising therapeutic strategy, as it can reduce both fibrotic and inflammatory responses. We aimed to investigate the anti-inflammatory and anti-fibrotic effect of CM on human pulmonary subepithelial myofibroblasts (hPSM) and on A549 pulmonary epithelial cells, treated with pro-inflammatory or pro-fibrotic mediators. CM inhibited the proinflammatory cytokine-induced mRNA and protein production of various chemokines in both hPSMs and A549 cells. It also downregulated the mRNA expression of IL-1α, but upregulated IL-1β and IL-6 mRNA production in both cell types. CM downregulated the pro-fibrotic-induced mRNA expression of collagen Type III and the migration rate of hPSMs, but upregulated fibronectin mRNA production and the total protein collagen secretion. CM's direct effect on the chemotaxis and cell recruitment of immune-associated cells, and its indirect effect on fibrosis through the significant decrease in the migration capacity of hPSMs, makes it a plausible candidate for further development towards a therapeutic treatment for IPF.