TRIM33 prevents pulmonary fibrosis by impairing TGF-β1 signalling

Epigenetic targets and their inhibitors in the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a deadly lung disease characterized by fibroblast proliferation, excessive extracellular matrix buildup, inflammation, and tissue damage, resulting in respiratory failure and death. Recent studies suggest that impaired interactions among epithelial, mesenchymal, immune, and endothelial cells play a key role in IPF development. Advances in bioinformatics have also linked epigenetics, which bridges gene expression and environmental factors, to IPF. Despite the incomplete understanding of the pathogenic mechanisms underlying IPF, recent preclinical studies have identified several novel epigenetic therapeutic targets, including DNMT, EZH2, G9a/GLP, PRMT1/7, KDM6B, HDAC, CBP/p300, BRD4, METTL3, FTO, and ALKBH5, along with potential small-molecule inhibitors relevant for its treatment. This review explores the pathogenesis of IPF, emphasizing epigenetic therapeutic targets and potential small molecule drugs. It also analyzes the structure-activity relationships of these epigenetic drugs and summarizes their biological activities. The objective is to advance the development of innovative epigenetic therapies for IPF.

13-Methylpalmatine alleviates bleomycin-induced pulmonary fibrosis by suppressing the ITGA5/TGF-β/Smad signaling pathway

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an irreversible lung disease for which there is a lack of effective and safe therapeutic drugs. 13-Methylpalmatine (13-Me-PLT) is an active compound from Coptis chinensis, and no study has yet been reported on its pharmacological effects in pulmonary fibrotic diseases. The group has previously demonstrated the antimyocardial fibrosis efficacy of 13-Me-PLT but its effect on pulmonary fibrosis and its potential mechanism has not yet been investigated.

PURPOSE

The present research is designed to clarify the therapeutic potential and mechanism of action of 13-Me-PLT in IPF using a bleomycin (BLM)-induced mouse model of IPF.

METHODS

In vivo, mice were administrated with BLM to establish the IPF model, and IPF mice were treated with 13-Me-PLT (5, 10, and 20 mg/kg) and pirfenidone (PFD, 300 mg/kg) by gavage. In vitro, we employed TGF-β1 (10 ng/ml)-induced MRC5 cells, which were then treated with 13-Me-PLT (5, 10, 20 μM) and PFD (500 μM). High-throughput transcriptome sequencing, molecular dynamics simulations, molecular docking and Surface plasmon resonance (SPR) were employed to elucidate the underlying mechanisms of 13-Me-PLT in mitigating IPF.

RESULT

In vivo experiments showed that 13-Me-PLT significantly ameliorated BLM-induced lung fibrosis in mice. In vitro studies, 13-Me-PLT showed good antifibrotic potential by inhibiting fibroblast differentiation. Transcriptomic analysis of mouse lung tissues identified ITGA5 and TGF-β/Smad signaling pathways as key targets for the antifibrotic effects of 13-Me-PLT. Molecular docking and kinetic analyses further supported these findings. Functional studies involving ITGA5 silencing and overexpression confirmed that 13-Me-PLT down-regulated ITGA5 expression and inhibited the activation of the TGF-β/Smad signaling pathway, confirming its mechanism of action.

CONCLUSION

To our best knowledge, these results provide the first insight that 13-Me-PLT is protective against BLM-induced IPF in mice. Unlike existing antifibrotic drugs, 13-Me-PLT specifically targets the ITGA5/TGF-β/Smad signaling pathway, offering a novel and potentially more effective therapeutic approach. This study not only validates the antifibrotic efficacy of 13-Me-PLT but also elucidates its unique mechanism of action, these findings may provide an opportunity to develop new drugs to treat IPF.

Phosphatase PHLPP1 is an alveolar-macrophage-intrinsic transcriptional checkpoint controlling pulmonary fibrosis

Alveolar macrophages (AMs) are crucial for lung homeostasis, and their dysfunction causes uncontrolled fibrotic responses and pulmonary disorders. Protein phosphatases control multiple cellular events. However, whether nuclear phosphatases cooperate with histone modifiers to affect pulmonary fibrosis progress remains obscure. Here, we identified pleckstrin homology domain and leucine-rich repeat protein phosphatase 1 (PHLPP1) as a key protective factor for pulmonary fibrosis. Transcriptomics and epigenomics data confirmed that PHLPP1 selectively targeted Kruppel-like factor 4 (KLF4) for transcriptional inhibition in AMs. Nuclear PHLPP1 directly bound and dephosphorylated histone deacetylase 8 (HDAC8) at serine 39, thereby enhancing its deacetylase enzyme activity and subsequently suppressing KLF4 expression via the decreased histone acetylation and chromatin accessibility. Thus, loss of PHLPP1 amplified KLF4-centric profibrotic transcriptional program in AMs, while intratracheal administration of Klf4-short hairpin RNA (shRNA) adeno-associated virus ameliorated lung fibrosis in PHLPP1-deficient mice. Our study implies that targeting decreased PHLPP1 in AMs might be a promising therapeutic strategy for pulmonary fibrosis.

Gut microbe-derived betulinic acid alleviates sepsis-induced acute liver injury by inhibiting macrophage NLRP3 inflammasome in mice

Sepsis-induced acute liver injury (SALI) is a prevalent and life-threatening complication associated with sepsis. The gut microbiota plays a crucial role in the maintenance of health and the development of diseases. The impact of physical exercise on gut microbiota modulation has been well-documented. However, the potential impact of gut microbiome on exercise training-induced protection against SALI remains uncertain. Here, we discovered exercise training ameliorated SALI and systemic inflammation in septic mice. Notably, gut microbiota pre-depletion abolished the protective effects of exercise training in SALI mice. Fecal microbiota transplantation treatment revealed that exercise training-associated gut microbiota contributed to the beneficial effect of exercise training on SALI. Exercise training modulated the metabolism of Ligilactobacillus and enriched betulinic acid (BA) levels in mice. Functionally, BA treatment conferred protection against SALI by inhibiting the hepatic inflammatory response in mice. BA bound and inactivated hnRNPA2B1, thus suppressing NLRP3 inflammasome activation in macrophages. Collectively, this study reveals gut microbiota is involved in the protective effects of exercise training against SALI, and gut microbiota-derived BA inhibits the hepatic inflammatory response via the hnRNPA2B1-NLRP3 axis, providing a potential therapeutic strategy for SALI.

IMPORTANCE

Sepsis is characterized by a dysregulated immune response to an infection that leads to multiple organ dysfunction. The occurrence of acute liver injury is frequently observed during the initial stage of sepsis and is directly linked to mortality in the intensive care unit. The preventive effect of physical exercise on SALI is well recognized, yet the underlying mechanism remains poorly elucidated. Exercise training alters the gut microbiome in mice, increasing the abundance of Ligilactobacillus and promoting the generation of BA. Additionally, BA supplementation can suppress the NLRP3 inflammasome activation in macrophages by directly binding to hnRNPA2B1, thereby mitigating SALI. These results highlight the beneficial role of gut microbiota-derived BA in inhibiting the hepatic inflammatory response, which represents a crucial stride toward implementing microbiome-based therapeutic strategies for the clinical management of sepsis.

[Targeting the TGF-β pathway in pulmonary fibrosis: Is it still a relevant strategy?]

Idiopathic pulmonary fibrosis (IPF) is a rare, progressive and fatal disease without pharmacologic curative treatments for the patients. TGF-β is a crucial cytokine in the fibrotic process, and its intracellular signaling pathways are complex and rely on the activation of its receptor. This review summarizes our knowledge on the regulatory checkpoints of the TGF-β signaling. In addition, the main strategies and key potential therapeutic targets identified over recent years are presented, with particular emphasis laid on how they can be used to develop new treatments for pulmonary fibrosis.

Phosphorylation of FOXN3 by NEK6 promotes pulmonary fibrosis through Smad signaling

The transcriptional repressor FOXN3 plays a key role in regulating pulmonary inflammatory responses, which are crucial in the development of pulmonary fibrosis. However, its specific regulatory function in lung fibrosis remains unclear. Here, we show that FOXN3 suppresses pulmonary fibrosis by inhibiting Smad transcriptional activity. FOXN3 targets a substantial number of Smad response gene promoters, facilitating Smad4 ubiquitination, which disrupts the association of the Smad2/3/4 complex with chromatin and abolishes its transcriptional response. In response to pro-fibrotic stimuli, NEK6 phosphorylates FOXN3 at S412 and S416, leading to its degradation. The loss of FOXN3 inhibits β-TrCP-mediated ubiquitination of Smad4, stabilizing the Smad complex's association with its responsive elements and promoting transcriptional activation, thus contributing to the development of pulmonary fibrosis. Notably, we found a significant inverse expression pattern between FOXN3 and Smad4 in clinical pulmonary fibrosis cases, underscoring the importance of the NEK6-FOXN3-Smad axis in the pathological process of pulmonary fibrosis.

Beyond Tumors: The Pivotal Role of TRIM Proteins in Chronic Non-Tumor Lung Diseases

While TRIM proteins are extensively studied in the context of lung tumors, their roles in non-tumor chronic lung diseases remain underexplored. This review delves into the emerging significance of TRIM family proteins in the pathogenesis of idiopathic pulmonary fibrosis (IPF), asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension (PH). TRIM proteins modulate key pathological processes, including inflammation, fibrosis, and cellular remodeling, contributing to disease progression. We highlight their potential as biomarkers and therapeutic targets, offering promising avenues for drug development in these debilitating respiratory disorders. However, the translation of these findings into clinical applications faces significant challenges. These include the dual functional nature of TRIM proteins, their context-dependent roles, the complexity of their downstream signaling networks, and the limitations of current therapeutic strategies in achieving tissue-specific targeting with minimal off-target effects. Addressing these challenges will require innovative approaches and interdisciplinary efforts to unlock the therapeutic potential of TRIM proteins in non-tumor chronic lung diseases.

C2C12 myoblasts differentiate into myofibroblasts via the TGF-β1 signaling pathway mediated by Fibulin2

Myoblasts play a critical role in the regeneration of skeletal muscle following injury. It has been reported that local elevation of transforming growth factor-β1 (TGF-β1) after skeletal muscle injury induces differentiation of myoblasts into myofibroblasts. However, the mechanisms underlying this differentiation process remain incompletely understood. In this study, we found that Fibulin2 expression significantly increases in myoblasts in response to TGF-β1 stimulation. Elevated Fibulin2 levels enhance the expression of fibrotic markers. Conversely, downregulation of Fibulin2 in myoblasts inhibits the upregulation of fibrotic markers induced by TGF-β1 stimulation. Extracellular secretion of Fibulin2 activates the TGF-β1-Smad2 pathway, thereby promoting the upregulation of fibrotic markers. Hence, Fibulin2 and TGF-β1 form a positive feedback loop that facilitates differentiation of myoblasts into myofibroblasts.

An FGF2-Derived Short Peptide Attenuates Bleomycin-Induced Pulmonary Fibrosis by Inhibiting Collagen Deposition and Epithelial-Mesenchymal Transition via the FGFR/MAPK Signaling Pathway

Following the COVID-19 pandemic, the prevalence of pulmonary fibrosis has increased significantly, placing patients at higher risk and presenting new therapeutic challenges. Current anti-fibrotic drugs, such as Nintedanib, can slow the decline in lung function, but their severe side effects highlight the urgent need for safer and more targeted alternatives. This study explores the anti-fibrotic potential and underlying mechanisms of an endogenous peptide (P5) derived from fibroblast growth factor 2 (FGF2), developed by our research team. Using a bleomycin-induced pulmonary fibrosis mouse model, we observed that P5 alleviated fibrosis by inhibiting collagen deposition, as confirmed by CT scans and histological staining. In TGF-β-induced cell models, P5 effectively suppressed collagen deposition and epithelial-mesenchymal transition (EMT). Transcriptome analysis highlighted pathways related to receptor binding, extracellular matrix organization, and cell adhesion, with KEGG analysis confirming FGFR/MAPK signaling inhibition as the primary mechanism underlying its anti-fibrotic effects. In summary, our study demonstrates that P5 significantly attenuates pulmonary fibrosis through the inhibition of EMT, collagen deposition, and FGFR/MAPK signaling, providing a promising therapeutic approach for fibrosis.

Ubiquitin proteasome system in cardiac fibrosis

BACKGROUND

Cardiac fibrosis, including reactive fibrosis and replacement fibrosis, is a common pathological process in most cardiovascular diseases. The ubiquitin proteasome system (UPS) plays an important role in the development of fibrosis by mediating the degradation and synthesis of proteins involved in transforming growth factor-β (TGF-β)-dependent and TGF-β-independent fibrous pathways.

AIM OF REVIEW

This review aims to provide an overview of ubiquitinated and deubiquitinated molecules that participating in cardiac fibrosis, with the ultimate purpose to identify promising targets for therapeutic strategies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The UPS primarily impacts cardiac fibrosis through modulation of the TGF-β signaling pathway targeting key molecules involved, including the TGF-β receptors, Smad2/3/4 complexes, and inhibitory Smad7, thereby influencing fibrotic processes. In addition to its effect on TGF-β signaling, UPS also regulates pro-fibrotic pathways independent of TGF-β, including p53, AKT1-p38, and JNK1/2. Understanding these pathways is critical due to their involvement in diverse fibrotic mechanisms. The interplay between ubiquitination and deubiquitination of crucial pathways and molecules is pivotal in cardiac fibrosis and represents a promising area for identifying novel therapeutic targets. Different types of cardiac fibrosis involve distinct fibrotic pathways, leading to differential effects of ubiquitin ligases (E3 ligases) and deubiquitinating enzymes (DUBs) across various cardiac fibrotic diseases. Insights into UPS-mediated regulation of cardiac fibrosis provide potential anti-fibrotic therapeutic strategies, emphasizing the importance of targeting UPS components specific to the heart for effective therapy against cardiac fibrosis.

Celastrol-Ligustrazine compound proven to be a novel drug candidate for idiopathic pulmonary fibrosis by intervening in the TGF-β1 mediated pathways-an experimental in vitro and vivo study

Idiopathic Pulmonary Fibrosis (IPF) is a disease characterized by pulmonary interstitial fibrosis and collagen proliferation, currently lacking effective therapeutic options. The combined use of Celastrol and Ligustrazine has been proved to synergistically improve the pathological processes of inflammation and fibrosis. In earlier studies, we designed and synthesized a Celastrol-Ligustrazine compound CL-001, though its role in IPF remains unclear. Here, the effects and mechanisms of CL-001 in bleomycin (BLM)-induced IPF were investigated. In vivo, CL-001 significantly improved lung function, reduced pulmonary inflammation, and decreased collagen deposition, thereby preventing the progression of IPF. In vitro, CL-001 concurrently inhibited both Smad-dependent and Smad-independent pathways, thereby suppressing TGF-β1-induced epithelial-mesenchymal transition (EMT) and epithelial cell migration. This inhibitory effect was superior to that of Celastrol or Ligustrazine administered alone. Additionally, CL-001 significantly increased the level of apoptosis and promoted the expression of apoptosis-related proteins (Caspase-8 and PARP), ultimately leading to widespread apoptosis in activated lung epithelial cells. In summary, CL-001 exhibits excellent anti-IPF effects both in vitro and in vivo, suggesting its potential as a novel candidate drug for IPF, warranting further development.

Injectable, degradable, and mechanically adaptive hydrogel induced by L-serine and allyl-functionalized chitosan with platelet-rich plasma for treating intrauterine adhesions

The integration of barrier materials with pharmacological therapy is a promising strategy to treat intrauterine adhesions (IUAs). However, most of these materials are surgically implanted in a fixed shape and incongruence with the natural mechanical properties of the uterus, causing poor adaptability and significant discomfort to the patients. Herein, an injectable, biodegradable, and mechanically adaptive hydrogel loaded with platelet-rich plasma (PRP) is created by L‑serine and allyl functionalized chitosan (ACS) to achieve efficient, comfortable, and minimally invasive treatment of IUAs. L‑serine induces fast gelation and mechanical reinforcement of the hydrogel, while ACS introduces, imparting a good injectability and complaint yet strong feature to the hydrogel. This design enables the hydrogel to adapt to the complex geometry and match the mechanical properties of the uterine. Moreover, the hydrogel exhibits proper degradability, sustained growth factors (GFs) of PRP release ability, and good biocompatibility. Consequently, the hydrogel shows promising therapeutic efficacy by reducing collagen fiber deposition and facilitating endometrium cell proliferation, thereby restoring the fertility function of the uterus in an IUAs model of rats. Accordingly, the combination of L‑serine and ACS-induced hydrogel with such advantages holds great potential for treating IUAs. STATEMENT OF SIGNIFICANCE: This research introduces a breakthrough in the treatment of intrauterine adhesions (IUAs) with an injectable, biodegradable and mechanically adaptive hydrogel using L‑serine and allyl functionalized chitosan (ACS). Unlike traditional surgical treatments, this hydrogel uniquely conforms to the uterus's geometry and mechanical properties, offering a minimally invasive, comfortable, and more effective solution. The hydrogel is designed to release growth factors from platelet-rich plasma (PRP) sustainably, promoting tissue regeneration by enhancing collagen fiber deposition and endometrium cell proliferation. Demonstrated efficacy in a rat model of IUAs indicates its great potential to significantly improve fertility restoration treatments. This advancement represents a significant leap in reproductive medicine, promising to transform IUAs treatment with its innovative approach to achieving efficient, comfortable, and minimally invasive therapy.

Advances in common in vitro cellular models of pulmonary fibrosis

The development of in vitro models is essential for a comprehensive understanding and investigation of pulmonary fibrosis (PF) at both cellular and molecular levels. This study presents a literature review and an analysis of various cellular models used in scientific studies, specifically focusing on their applications in elucidating the pathogenesis of PF. Our study highlights the importance of taking a comprehensive approach to studing PF, emphasizing the necessity of considering multiple cell types and organs and integrating diverse analytical perspectives. Notably, primary cells demonstrate remarkable cell growth characteristics and gene expression profiles; however, their limited availability, maintenance challenges, inability for continuous propagation and susceptibility to phenotypic changes over time significantly limit their utility in scientific investigation. By contrast, immortalized cell lines are easily accessible, cultured and continuously propagated, although they may have some phenotypic differences from primary cells. Furthermore, in vitro coculture models offer a more practical and precise method to explore complex interactions among cells, tissues and organs. Consequently, when developing models of PF, researchers should thoroughly assess the advantages, limitations and relevant mechanisms of different cell models to ensure their selection is consistent with the research objectives.

Regulation of myofibroblast dedifferentiation in pulmonary fibrosis

Idiopathic pulmonary fibrosis is a lethal, progressive, and irreversible condition that has become a significant focus of medical research due to its increasing incidence. This rising trend presents substantial challenges for patients, healthcare providers, and researchers. Despite the escalating burden of pulmonary fibrosis, the available therapeutic options remain limited. Currently, the United States Food and Drug Administration has approved two drugs for the treatment of pulmonary fibrosis-nintedanib and pirfenidone. However, their therapeutic effectiveness is limited, and they cannot reverse the fibrosis process. Additionally, these drugs are associated with significant side effects. Myofibroblasts play a central role in the pathophysiology of pulmonary fibrosis, significantly contributing to its progression. Consequently, strategies aimed at inhibiting myofibroblast differentiation or promoting their dedifferentiation hold promise as effective treatments. This review examines the regulation of myofibroblast dedifferentiation, exploring various signaling pathways, regulatory targets, and potential pharmaceutical interventions that could provide new directions for therapeutic development.

Network pharmacology and experimental verification to decode the action of Qing Fei Hua Xian Decotion against pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis (PF) is a common interstitial pneumonia disease, also occurred in post-COVID-19 survivors. The mechanism underlying the anti-PF effect of Qing Fei Hua Xian Decotion (QFHXD), a traditional Chinese medicine formula applied for treating PF in COVID-19 survivors, is unclear. This study aimed to uncover the mechanisms related to the anti-PF effect of QFHXD through analysis of network pharmacology and experimental verification.

METHODS

The candidate chemical compounds of QFHXD and its putative targets for treating PF were achieved from public databases, thereby we established the corresponding "herb-compound-target" network of QFHXD. The protein-protein interaction network of potential targets was also constructed to screen the core targets. Furthermore, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to predict targets, and pathways, then validated by in vivo experiments.

RESULTS

A total of 188 active compounds in QFHXD and 50 target genes were identified from databases. The key therapeutic targets of QFHXD, such as PI3K/Akt, IL-6, TNF, IL-1β, STAT3, MMP-9, and TGF-β1 were identified by KEGG and GO analysis. Anti-PF effects of QFHXD (in a dose-dependent manner) and prednisone were confirmed by HE, Masson staining, and Sirius red staining as well as in vivo Micro-CT and immunohistochemical analysis in a rat model of bleomycin-induced PF. Besides, QFXHD remarkably inhibits the activity of PI3K/Akt/NF-κB and TGF-β1/Smad2/3.

CONCLUSIONS

QFXHD significantly attenuated bleomycin-induced PF via inhibiting inflammation and epithelial-mesenchymal transition. PI3K/Akt/NF-κB and TGF-β1/Smad2/3 pathways might be the potential therapeutic effects of QFHXD for treating PF.

Kynurenine acts as a signaling molecule to attenuate pulmonary fibrosis by enhancing the AHR-PTEN axis

INTRODUCTION

Pulmonary fibrosis (PF) is a fatal fibrotic lung disease without any options to halt disease progression. Feasible evidence suggests that aberrant metabolism of amino acids may play a role in the pathoetiology of PF. However, the exact impact of kynurenine (Kyn), a metabolite derived from tryptophan (Trp) on PF is yet to be addressed.

OBJECTIVES

This study aims to elucidate the role of kynurenine in both the onset and advancement of PF.

METHODS

Liquid chromatography-tandem mass spectrometry was employed to assess Kyn levels in patients with idiopathic PF and PF associated with Sjögren's syndrome. Additionally, a mouse model of PF induced by bleomycin was utilized to study the impact of Kyn administration. Furthermore, cell models treated with TGF-β1 were used to explore the mechanism by which Kyn inhibits fibroblast functions.

RESULTS

We demonstrated that high levels of Kyn are a clinical feature in both idiopathic PF patients and primary Sjögren syndrome associated PF patients. Further studies illustrated that Kyn served as a braking molecule to suppress fibroblast functionality, thereby protecting mice from bleomycin-induced lung fibrosis. The protective effects depend on AHR, in which Kyn induces AHR nuclear translocation, where it upregulates PTEN expression to blunt TGF-β mediated AKT/mTOR signaling in fibroblasts. However, in fibrotic microenviroment, the expression of AHR is repressed by methyl-CpG-binding domain 2 (MBD2), a reader interpreting the effect of DNA methylation, which results in a significantly reduced sensitivity of Kyn to fibroblasts. Therefore, exogenous administration of Kyn substantially reversed established PF.

CONCLUSION

Our studies not only highlighted a critical role of Trp metabolism in PF pathogenesis, but also provided compelling evidence suggesting that Kyn could serve as a promising metabolite against PF.

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

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

Multi-omics integration highlights the role of ubiquitination in endometriosis fibrosis

BACKGROUND

Endometriosis, characterized by the presence of active endometrial-like tissues outside the uterus, causes symptoms like dysmenorrhea and infertility due to the fibrosis of endometrial cells, which involves excessive deposition of extracellular matrix (ECM) proteins. Ubiquitination, an important post-transcriptional modification, regulates various biological processes in human diseases. However, its role in the fibrosis process in endometriosis remains unclear.

METHODS

We employed multi-omics approaches on two cohorts of endometriosis patients with 39 samples. GO terms and KEGG pathways enrichment analyses were used to investigate the functional changes involved in endometriosis. Pearson's correlation coefficient analysis was conducted to explore the relationship between global proteome and ubiquitylome in endometriosis. The protein expression levels of ubiquitin-, fibrosis-related proteins, and E3 ubiquitin-protein ligase TRIM33 were validated via Western blot. Transfecting human endometrial stroma cells (hESCs) with TRIM33 small interfering RNA (siRNA) in vitro to explore how TRIM33 affects fibrosis-related proteins.

RESULTS

Integration of proteomics and transcriptomics showed genes with concurrent change of both mRNA and protein level which involved in ECM production in ectopic endometria. Ubiquitylomics distinguished 1647 and 1698 ubiquitinated lysine sites in the ectopic (EC) group compared to the normal (NC) and eutopic (EU) groups, respectively. Further multi-omics integration highlighted the essential role of ubiquitination in key fibrosis regulators in endometriosis. Correlation analysis between proteome and ubiquitylome showed correlation coefficients of 0.32 and 0.36 for ubiquitinated fibrosis proteins in EC/NC and EC/EU groups, respectively, indicating positive regulation of fibrosis-related protein expression by ubiquitination in ectopic lesions. We identified ubiquitination in 41 pivotal proteins within the fibrosis-related pathway of endometriosis. Finally, the elevated expression of TGFBR1/α-SMA/FAP/FN1/Collagen1 proteins in EC tissues were validated across independent samples. More importantly, we demonstrated that both the mRNA and protein levels of TRIM33 were reduced in endometriotic tissues. Knockdown of TRIM33 promoted TGFBR1/p-SMAD2/α-SMA/FN1 protein expressions in hESCs but did not significantly affect Collagen1/FAP levels, suggesting its inhibitory effect on fibrosis in vitro.

CONCLUSIONS

This study, employing multi-omics approaches, provides novel insights into endometriosis ubiquitination profiles and reveals aberrant expression of the E3 ubiquitin ligase TRIM33 in endometriotic tissues, emphasizing their critical involvement in fibrosis pathogenesis and potential therapeutic targets.

Amorphous curcumin-based hydrogels to reduce the incidence of post-surgical intrauterine adhesions

The incidence of intrauterine adhesions (IUA) has increased with the rising utilization of intrauterine surgery. The postoperative physical barrier methods commonly used, such as balloons and other fillers, have limited effectiveness and may even cause further damage to the remaining endometrial tissue. Herein, we developed an injectable thermosensitive hydrogel using Pluronic F127/F68 as pharmaceutical excipients and curcumin as a natural active molecule. The hydrogel effectively addresses solubility and low bioavailability issues associated with curcumin. In vitro, drug release assays revealed that the amorphous curcumin hydrogel promotes dissolution and sustained release of curcumin. In vitro experiments reveal high biocompatibility of the hydrogel and its ability to enhance vascular formation while inhibiting the expression of fibrotic factor TGF-β1. To assess the effectiveness of preventing IUAs, in vivo experiments were conducted using IUA rats and compared with a class III medical device, a new-crosslinked hyaluronic acid (NCHA) gel. According to the study, curcumin hydrogel is more effective than the NCHA group in improving the regeneration of the endometrium, increasing the blood supply to the endometrium and reducing the abnormal deposition of fibrin, thus preventing IUA more effectively. This study provides a promising strategy for treating and preventing IUA.

A novel fatty acid analogue triggers CD36-GPR120 interaction and exerts anti-inflammatory action in endotoxemia

Inflammation is a mediator of a number of chronic pathologies. We synthesized the diethyl (9Z,12Z)-octadeca-9,12-dien-1-ylphosphonate, called NKS3, which decreased lipopolysaccharide (LPS)-induced mRNA upregulation of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) not only in primary intraperitoneal and lung alveolar macrophages, but also in freshly isolated mice lung slices. The in-silico studies suggested that NKS3, being CD36 agonist, will bind to GPR120. Co-immunoprecipitation and proximity ligation assays demonstrated that NKS3 induced protein-protein interaction of CD36 with GPR120in RAW 264.7 macrophage cell line. Furthermore, NKS3, via GPR120, decreased LPS-induced activation of TAB1/TAK1/JNK pathway and the LPS-induced mRNA expression of inflammatory markers in RAW 264.7 cells. In the acute lung injury model, NKS3 decreased lung fibrosis and inflammatory cytokines (IL-1β, IL-6 and TNF-α) and nitric oxide (NO) production in broncho-alveolar lavage fluid. NKS3 exerted a protective effect on LPS-induced remodeling of kidney and liver, and reduced circulating IL-1β, IL-6 and TNF-α concentrations. In a septic shock model, NKS3 gavage decreased significantly the LPS-induced mortality in mice. In the last, NKS3 decreased neuroinflammation in diet-induced obese mice. Altogether, these results suggest that NKS3 is a novel anti-inflammatory agent that could be used, in the future, for the treatment of inflammation-associated pathologies.

CD109 identified in circulating proteomics mitigates postoperative recurrence in chronic rhinosinusitis with nasal polyps by suppressing TGF-β1-induced epithelial-mesenchymal transition

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common inflammatory disorder with a high rate of recurrence. This study aimed to explore biomarkers for identifying patients with recurrent CRSwNP (rCRSwNP).

METHODS

We recruited two independent cohorts. In the discovery cohort, rCRSwNP patients and non-recurrent CRSwNP (non-rCRSwNP) patients were recruited, and the serum proteomic profile was characterized. The top 5 upregulated and downregulated proteins were confirmed in the validation cohort by ELISA, WB, and qRT-PCR, and their predictive values for postoperative recurrence were assessed. In vitro, human nasal epithelial cells (HNEpCs) were employed to assess the ability of candidate proteins to induce epithelial-mesenchymal transition (EMT).

RESULTS

Serum proteomics identified 53 different proteins, including 30 increased and 23 decreased, between the rCRSwNP and non-rCRSwNP groups. ELISA results revealed that serum levels of CD163 and TGF-β1 were elevated, CD109 and PRDX2 were decreased in the rCRSwNP group compared to the non-rCRSwNP group, and serum CD163, TGF-β1, and CD109 levels were proved to be associated with the risk of postoperative recurrence. In addition, qRT-PCR and WB revealed that tissue CD163, TGF-β1, and CD109 expressions in rCRSwNP patients were enhanced compared to those non-rCRSwNP patients. Kaplan-Meier analysis showed that increased CD163 and TGF-β1 expression and decreased CD109 expression are associated with the risk of recurrence in CRSwNP patients. Receiver operating characteristic curves showed that TGF-β1 and CD109 had superior diagnostic performances for rCRSwNP. In vitro experiments showed that TGF-β1 promoted EMT in HNEpCs, and overexpression of CD109 reversed this effect. Functional recovery experiments confirmed that CD109 could attenuate EMT in HNEpCs by inhibiting the TGF-β1/Smad signaling pathway, attenuating EMT in epithelial cells.

CONCLUSION

Our data suggested that TGF-β1 and CD109 might serve as promising predictors of rCRSwNP. The TGF-β1/Smad pathway was implicated in fostering EMT in epithelial cells, particularly those exhibiting low expression of CD109. Consequently, the absence of CD109 expression in epithelial cells could be a potential mechanism underlying rCRSwNP.

The Effects of Budesonide Inhalation Treatment on the Expression Levels of Serum IL-6, TGF-β1, and IgE and Pulmonary Function in Patients with Cough Variant Asthma and an Evaluation of Treatment Efficacy

Objective

To retrospectively study the effects of budesonide inhalation combined with conventional symptomatic treatment on serum inflammatory factor expression levels and pulmonary function in patients with cough variant asthma (CVA) and to evaluate treatment efficacy.

Methods

This retrospective cohort study included 200 patients diagnosed with CVA at the Second Hospital of Jiaxing between January 2022 and June 2023 and given conventional symptomatic treatment plus budesonide inhalation were included in this study. Patients were divided into a no remission group, a partial remission group and a complete remission group based on treatment effect. The expression levels of serum inflammatory factors, cough symptom scores, and small airway function indicators in the three groups of patients at different time points were compared.

Results

In the three groups of CVA patients, after receiving budesonide inhalation combined with conventional symptomatic treatment, the expression levels of serum IL-5, IL-6, IL-8, TNF-α, TGF-β1, and IgE and number of eosinophils significantly decreased (P <0.05). There were statistically significant differences in the IL-6 and TGF-β1 levels among the three groups of CVA patients at T1, T2 and T3. There were statistically significant differences in IgE levels, number of eosinophils, cough symptom scores, and small airway function indicators between T2 and T3 (P<0.05). The receiver operating characteristic (ROC) curve prediction analysis revealed significant differences in the expression of IL-6 and TGF-β1 at T1, T2, and T3.

Conclusion

Budesonide inhalation combined with conventional symptomatic treatment can significantly reduce the levels of serum inflammatory factors in patients with CVA to reduce inflammation and the allergic response, thereby reducing the cough symptom score, improving pulmonary function, and improving therapeutic efficacy. In addition, IL-6 and TGF-β1 can be used as early predictors of budesonide inhalation efficacy.

circGRHPR inhibits aberrant epithelial-mesenchymal transformation progression of lung epithelial cells associated with idiopathic pulmonary fibrosis

Air pollution has greatly increased the risk of idiopathic pulmonary fibrosis (IPF). Circular RNAs (circRNAs) have been found to play a significant role in the advancement of IPF, but there is limited evidence of correlation between circRNAs and lung epithelial cells (LECs) in IPF. This research aimed to explore the influence of circRNAs on the regulation of EMT progression in LECs, with the objective of elucidating its mechanism and establishing its association with IPF. Our results suggested that the downregulation of circGRHPR in peripheral blood of clinical cases was associated with the diagnosis of IPF. Meanwhile, we found that circGRHPR was downregulated in transforming growth factor-beta1 (TGF-β1)-induced A549 and Beas-2b cells. It is a valid model to study the abnormal EMT progression of IPF-associated LECs in vitro. The overexpression of circGRHPR inhibited the abnormal EMT progression of TGF-β1-induced LECs. Furthermore, as the sponge of miR-665, circGRHPR released the expression of E3 ubiquitin-protein ligase NEDD4-like (NEDD4L), thus promoting its downstream transforming growth factor beta receptor 2 (TGFBR2) ubiquitination. It is helpful to reduce the response of LECs to TGF-β1 signaling. In summary, circGRHPR/miR-665/NEDD4L axis inhibited the abnormal EMT progression of TGF-β1-induced LECs by promoting TGFBR2 ubiquitination, which provides new ideas and potential targets for the treatment of IPF.

Inhibitor of PD-1/PD-L1: a new approach may be beneficial for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a globally prevalent, progressive disease with limited treatment options and poor prognosis. Because of its irreversible disease progression, IPF affects the quality and length of life of patients and imposes a significant burden on their families and social healthcare services. The use of the antifibrotic drugs pirfenidone and nintedanib can slow the progression of the disease to some extent, but it does not have a reverse effect on the prognosis. The option of lung transplantion is also limited owing to contraindications to transplantation, possible complications after transplantation, and the risk of death. Therefore, the discovery of new, effective treatment methods is an urgent need. Over recent years, various studies have been undertaken to investigate the relationship between interstitial pneumonia and lung cancer, suggesting that some immune checkpoints in IPF are similar to those in tumors. Immune checkpoints are a class of immunosuppressive molecules that are essential for maintaining autoimmune tolerance and regulating the duration and magnitude of immune responses in peripheral tissues. They can prevent normal tissues from being damaged and destroyed by the immune response. While current studies have focused on PD-1/PD-L1 and CTLA-4, PD-1/PD-L1 may be the only effective immune checkpoint IPF treatment. This review discusses the application of PD-1/PD-L1 checkpoint in IPF, with the aim of finding a new direction for IPF treatment.

Cytokines as drivers: Unraveling the mechanisms of epithelial-mesenchymal transition in COVID-19 lung fibrosis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), like other viruses, can induce proliferation of myofibroblasts and even lead to fibrosis in the lung. Epithelial-mesenchymal transition (EMT) is thought to play an essential role in the pathogenesis of Coronavirus disease 19 (COVID-19). EMT is originally a critical process that regulates the development of different tissues in the embryo, but in inflammatory situations, EMT tries to be activated again to control inflammation or even heal inflammatory damage. However, in pathological situations, such as chronic viral infections (e.g., COVID-19) or pulmonary fibrosis initiation, this benign healing transforms into sinister nature, pushing the lung into the fibrotic process. Notably, the cytokines released by inflammatory cells and the chronic inflammatory microenvironment shared by fibrotic cells promote each other as critical factors in the induction of pathological EMT. In the induction of SARS-CoV-2 virus, cytokines are an essential mediator of EMT transformation, and a summary of whether COVID-19 patients, during the infection phase, have many persistent inflammatory mediators (cytokines) that are a causative factor of EMT has not yet appeared. The following common signaling drivers, including Transforming growth factor beta (TGF-β), cytokines, Notch signaling pathway, Wnt and hypoxia signaling pathways, drive the regulation of EMT. In this review, we will focus on 3 key EMT signaling pathways: TGF-β, Leucine zipper transcription factor like 1 (LZTFL1) and the common interleukin family expressed in the lung. TGF-β-induced SNAIL and LZTFL1 were identified as regulatory EMT in COVID-19. For cytokines, the interleukin family is a common inducer of EMT and plays an essential role in the formation of the microenvironment of fibrosis. We sought to demonstrate that cytokines act as "communicators" and build the "microenvironment" of fibrosis together with EMT as a "bridge" to induce EMT in fibrosis. The mechanisms utilized by these two pathways could serve as templates for other mesenchymal transformations and provide new potential 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.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Clinical features of dermatomyositis patients with anti-TIF1 antibodies: A case based comprehensive review

BACKGROUND AND OBJECTIVES

Dermatomyositis is chronic autoimmune disease primarily affecting skin and muscles. Antibodies are key players of pathogenesis and are in strong correlation with distinct clinical phenotypes. We present a case and a comprehensive review of the literature on dermatomyositis patients with Anti TIF1 antibodies.

METHODS

PubMed and Web of Science databases were reviewed. 166 articles were identified; 95 of them were evaluated; 79 of them included to the study. 45 of the included articles were case reports 9 were case series and 25 were research articles. In total 1065 patients were identified but number of patients with available information for different clinical features varied.

RESULTS

69.6% of the patients with Anti TIF1-γ were female. Prevalence of malignancy was 42.6% among patients with Anti TIF1-γ. Muscle weakness (83%), Gottron sign (82.2%), heliotrope rash (73.7%), nailfold capillary changes (67.7%), dysphagia (38.4%), and joint involvement (31.1%) were the most common clinical features seen in patients with Anti TIF1-γ. Interstitial lung disease (ILD) was reported among 8.7% of patients with Anti TIF1-γ. Advanced age, male gender, dysphagia, and V-neck rash were significant risk factors for malignancy, whereas juvenile age, ILD, TIF1-β antibodies and joint involvement were associated with a decreased risk for malignancy. Advanced age, malignancy, dysphagia, and muscle involvement were associated with an increased risk for mortality.

CONCLUSIONS

Patients with advanced age, male gender, dysphagia, and V-neck rash require strict cancer screening. Patients with advanced age, malignancy, dysphagia, and muscle involvement have poor prognosis and should receive aggressive treatment.

ADRB2 inhibition combined with antioxidant treatment alleviates lung fibrosis by attenuating TGFβ/SMAD signaling in lung fibroblasts

Idiopathic pulmonary fibrosis is a progressive and fatal interstitial lung disease with a poor prognosis and limited therapeutic options, which is characterized by aberrant myofibroblast activation and pathological remodeling of the extracellular matrix, while the mechanism remains elusive. In the present investigation, we observed a reduction in ADRB2 expression within both IPF and bleomycin-induced fibrotic lung samples, as well as in fibroblasts treated with TGF-β1. ADRB2 inhibition blunted bleomycin-induced lung fibrosis. Blockage of the ADRB2 suppressed proliferation, migration, and invasion and attenuated TGF-β1-induced fibroblast activation. Conversely, the enhancement of ADRB2 expression or functionality proved capable of inducing fibroblast-to-myofibroblast differentiation. Subsequent mechanistic investigation revealed that inhibition of ADRB2 suppressed the activation of SMAD2/3 in lung fibroblasts and increased phos-SMAD2/3 proteasome degradation, and vice versa. Finally, ADRB2 inhibition combined with antioxidants showed increased efficacy in the therapy of bleomycin-induced lung fibrosis. In short, these data indicate that ADRB2 is involved in lung fibroblast differentiation, and targeting ADRB2 could emerge as a promising and innovative therapeutic approach for pulmonary fibrosis.

Nuclear translocation of PKM2 mediates keratinocyte metabolic reprogramming in psoriasis

PKM2 mediates the Warburg effects and is crucial for tumorigenesis, but its role in hyperplastic skin disorders remains elusive. In this study, we investigated the function of PKM2 in psoriatic keratinocytes. We found that PKM2 expression and its nuclear translocation were induced in the epidermis of psoriasis patients, contributing to aerobic glycolysis and cell growth. Moreover, mass spectrometry combined with immunoprecipitation analysis revealed that PKM2 could interact with TRIM33, an E3 ubiquitin ligase in the nucleus, and this interaction is critical for the nuclear retention of PKM2. As a result of TRIM33-mediated ubiquitination, PKM2 nuclear protein kinase function is promoted, thus leading to the phosphorylation of STAT3. In addition, blocking PKM2 nuclear translocation abrogated TRIM33-triggered glycolysis and cell proliferation in keratinocytes. Taken together, our experiments demonstrate that ubiquitination regulates the nuclear retention of PKM2 in keratinocytes. Moreover, our results highlight a novel mechanism accounting for the metabolic reprogramming of keratinocytes in psoriasis patients.

Tubular cell transcriptional intermediary factor 1γ deficiency exacerbates kidney injury-induced tubular cell polyploidy and fibrosis

Tubulointerstitial fibrosis is considered the final convergent pathway of progressive chronic kidney diseases (CKD) regardless of etiology. However, mechanisms underlying kidney injury-induced fibrosis largely remain unknown. Recent studies have indicated that transcriptional intermediary factor 1γ (TIF1γ) inhibits the progression of fibrosis in other organs. Here, we found that TIF1γ was highly expressed in the cytoplasm and nucleus of the kidney proximal tubule. Interestingly, we found tubular TIF1γ expression was decreased in patients with CKD, including those with diabetes, hypertension, and IgA nephropathy, and in mouse models with experimental kidney fibrosis (unilateral ureteral obstruction [UUO], folic acid nephropathy [FAN], and aristolochic acid-induced nephrotoxicity). Tubule-specific knock out of TIF1γ in mice exacerbated UUO- and FAN-induced tubular cell polyploidy and subsequent fibrosis, whereas overexpression of kidney TIF1γ protected mice against kidney fibrosis. Mechanistically, in tubular epithelial cells, TIF1γ exerted an antifibrotic role via transforming growth factor-β (TGF-β)-dependent and -independent signaling. TIF1γ hindered TGF-β signaling directly by inhibiting the formation and activity of the transcription factor Smad complex in tubular cells, and we discovered that TIF1γ suppressed epidermal growth factor receptor (EGFR) signaling upstream of TGF-β signaling in tubular cells by ubiquitylating EGFR at its lysine 851/905 sites thereby promoting EGFR internalization and lysosomal degradation. Pharmacological inhibition of EGFR signaling attenuated exacerbated polyploidization and the fibrotic phenotype in mice with tubule deletion of TIF1γ. Thus, tubular TIF1γ plays an important role in kidney fibrosis by suppressing profibrotic EGFR and TGF-β signaling. Hence, our findings suggest that maintaining homeostasis of tubular TIF1γ may be a new therapeutic option for treating tubulointerstitial fibrosis and subsequent CKD.

Epigenetic hallmarks in pulmonary fibrosis: New advances and perspectives

Epigenetics indicates that certain phenotypes of an organism can undergo heritable changes in the absence of changes in the genetic DNA sequence. Many studies have shown that epigenetic patterns play an important role in the lung and lung diseases. Pulmonary fibrosis (PF) is also a type of lung disease. PF is an end-stage change of a large group of lung diseases, characterized by fibroblast proliferation and massive accumulation of extracellular matrix, accompanied by inflammatory injury and histological destruction, that is, structural abnormalities caused by abnormal repair of normal alveolar tissue. It causes loss of lung function in patients with multiple complex diseases, leading to respiratory failure and subsequent death. However, current treatment options for IPF are very limited and no drugs have been shown to significantly prolong the survival of patients. Therefore, based on a systematic understanding of the disease mechanisms of PF, this review integrates the role of epigenetics in the development and course of PF, describes preventive and potential therapeutic targets for PF, and provides a theoretical basis for further exploration of the mechanisms of PF.

Macrophage Implication in IPF: Updates on Immune, Epigenetic, and Metabolic Pathways

Idiopathic pulmonary fibrosis (IPF) is a lethal interstitial lung disease of unknown etiology with a poor prognosis. It is a chronic and progressive disease that has a distinct radiological and pathological pattern from common interstitial pneumonia. The use of immunosuppressive medication was shown to be completely ineffective in clinical trials, resulting in years of neglect of the immune component. However, recent developments in fundamental and translational science demonstrate that immune cells play a significant regulatory role in IPF, and macrophages appear to be among the most crucial. These highly plastic cells generate multiple growth factors and mediators that highly affect the initiation and progression of IPF. In this review, we will provide an update on the role of macrophages in IPF through a systemic discussion of various regulatory mechanisms involving immune receptors, cytokines, metabolism, and epigenetics.

Rapidly progressive interstitial lung disease combined with pneumocystis jiroveci pneumonia in a patient with single anti-TIF-1γ antibody positive dermatomyositis in the context of an underlying tumor

BACKGROUND

Interstitial lung disease (ILD) is a frequently observed comorbidity in autoimmune diseases such as dermatomyositis/polymyositis (DM/PM), and it is significantly associated with specific autoantibody types. One unique antibody type is the anti-transcription intermediate factor-1γ antibody (anti-TIF-1γ Ab), which has a positive rate of only 7%. It is often found in combination with malignancy and rarely with ILD, particularly rapidly progressive ILD (RPILD). In some cases, the presence of ILD in individuals with DM may indicate a paraneoplastic syndrome. Pneumocystis jiroveci pneumonia (PJP) typically occurs due to intensive immunosuppressive therapy, human immunodeficiency virus (HIV) infection, or malignancy, and rarely as an isolated condition.

CASE PRESENTATION

A 52-year-old man with a history of rapid weight loss but non-HIV infected and not immunosuppressed who presented with fever, cough, dyspnea, weakness of the extremities, characteristic rash and mechanic's hand. Pathogenic tests suggested PJP, laboratory tests suggested a single anti-TIF-1γ Ab positive DM, imaging suggested ILD, and pathology revealed no malignancy. RPILD and acute respiratory distress syndrome (ARDS) developed after anti-infection and steroid hormone therapy. After mechanical support therapy such as Extracorporeal Membrane Oxygenation (ECMO), the patient developed late-onset cytomegalovirus pneumonia (CMVP), complicated bacterial infection, and ultimately death. Additionally, we discuss the potential causes of rapid weight loss, the mechanisms by which anti-TIF-1γ Ab may lead to ILD, and the possible connection between anti-TIF-1γ Ab positivity, rapid weight loss, immune abnormalities, and opportunistic infections.

CONCLUSIONS

This case emphasizes the importance of early recognition of malignant tumors and pulmonary lesions, assessment of the body's immune status, prompt initiation of immunosuppressive treatment, and prevention of opportunistic infections in individuals with single anti-TIF-1γ Ab positive DM presenting with rapid weight loss.

Two-Pore-Domain Potassium Channel TREK-1 Mediates Pulmonary Fibrosis through Macrophage M2 Polarization and by Direct Promotion of Fibroblast Differentiation

Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by myofibroblast proliferation and abnormal accumulation of extracellular matrix in the lungs. After lung injury, M2 macrophages mediate the pathogenesis of pulmonary fibrosis by secreting fibrotic cytokines that promote myofibroblast activation. The TWIK-related potassium channel (TREK-1, also known as KCNK2) is a K2P channel that is highly expressed in cardiac, lung, and other tissues; it worsens various tumors, such as ovarian cancer and prostate cancer, and mediates cardiac fibrosis. However, the role of TREK-1 in lung fibrosis remains unclear. This study aimed to examine the effects of TREK-1 on bleomycin (BLM)-induced lung fibrosis. The results show that TREK-1 knockdown, mediated by the adenovirus or pharmacological inhibition of TREK-1 with fluoxetine, resulted in diminished BLM-induced lung fibrosis. TREK-1 overexpression in macrophages remarkably increased the M2 phenotype, resulting in fibroblast activation. Furthermore, TREK-1 knockdown and fluoxetine administration directly reduced the differentiation of fibroblasts to myofibroblasts by inhibiting the focal adhesion kinase (FAK)/p38 mitogen-activated protein kinases (p38)/Yes-associated protein (YAP) signaling pathway. In conclusion, TREK-1 plays a central role in the pathogenesis of BLM-induced lung fibrosis, which serves as a theoretical basis for the inhibition of TREK-1 as a potential therapy protocol for lung fibrosis.

Quercetin Alleviates Pulmonary Fibrosis in Silicotic Mice by Inhibiting Macrophage Transition and TGF-β-Smad2/3 Pathway

Silicosis is a pulmonary disease caused by the inhalation of silica. There is a lack of early and effective prevention, diagnosis, and treatment methods, and addressing silicotic fibrosis is crucial. Quercetin, a flavonoid with anti-carcinogenic, anti-inflammatory, and antiviral properties, is known to have a suppressive effect on fibrosis. The present study aimed to determine the therapeutic effect of quercetin on silicotic mice and macrophage polarity. We found that quercetin suppressed silicosis in mice. It was observed that SiO₂ activated macrophage polarity and the macrophage-to-myofibroblast transition (MMT) by transforming the growth factor-β (TGF-β)-Smad2/3 signaling pathway in silicotic mice and MH-S cells. Quercetin also attenuated the MMT and the TGF-β-Smad2/3 signaling pathway in vivo and in vitro. The present study demonstrated that quercetin is a potential therapeutic agent for silicosis, which acts by regulating macrophage polarity and the MMT through the TGF-β-Smad2/3 signaling pathway.

TREM2 Insufficiency Protects against Pulmonary Fibrosis by Inhibiting M2 Macrophage Polarization

Rationale Idiopathic pulmonary fibrosis (IPF) is a lung disease with high mortality, limited treatment options and an unknown aetiology. M2 macrophages play a critical role in the pathological process of IPF. Triggering receptor expressed on myeloid cells-2 (TREM2) participates in the regulation of macrophages, although its role in IPF remains elusive.

METHODS

This study examined the role of TREM2 in macrophage regulation using a well-established bleomycin (BLM)-induced pulmonary fibrosis (PF) mouse model. TREM2 insufficiency was induced by intratracheal treatment with TREM2-specific siRNA. The effects of TREM2 on IPF were evaluated using histological staining and molecular biological methods.

RESULTS

TREM2 expression levels were significantly elevated in the lungs of IPF patients and mice with BLM-induced pulmonary fibrosis mice. Bioinformatics analysis revealed that IPF patients with higher TREM2 expression had a shorter survival time, and that TREM2 expression was closely associated with fibroblasts and M2 macrophages. Gene Ontology (GO) enrichment analysis showed that found TREM2-related differentially expressed genes (DEGs) were associated with inflammatory responses, extracellular matrix (ECM) and collagen formation. Single-cell RNA sequencing analysis revealed that TREM2 was predominantly expressed in macrophages. TREM2 insufficiency inhibited BLM-induced pulmonary fibrosis and M2 macrophage polarization. Mechanistic studies showed that TREM2 insufficiency suppressed the activation of STAT6 and the expression of fibrotic factors such as Fibronectin (Fib), Collagen I (Col I) and α- smooth muscle actin (α-SMA).

CONCLUSION

Our study showed that TREM2 insufficiency might alleviate pulmonary fibrosis possibly through macrophage polarization regulation via STAT6 activation, providing a promising macrophage-related approach for the clinical therapy of pulmonary fibrosis.

Immune Mechanisms of Pulmonary Fibrosis with Bleomycin

Fibrosis and structural remodeling of the lung tissue can significantly impair lung function, often with fatal consequences. The etiology of pulmonary fibrosis (PF) is diverse and includes different triggers such as allergens, chemicals, radiation, and environmental particles. However, the cause of idiopathic PF (IPF), one of the most common forms of PF, remains unknown. Experimental models have been developed to study the mechanisms of PF, and the murine bleomycin (BLM) model has received the most attention. Epithelial injury, inflammation, epithelial-mesenchymal transition (EMT), myofibroblast activation, and repeated tissue injury are important initiators of fibrosis. In this review, we examined the common mechanisms of lung wound-healing responses after BLM-induced lung injury as well as the pathogenesis of the most common PF. A three-stage model of wound repair involving injury, inflammation, and repair is outlined. Dysregulation of one or more of these three phases has been reported in many cases of PF. We reviewed the literature investigating PF pathogenesis, and the role of cytokines, chemokines, growth factors, and matrix feeding in an animal model of BLM-induced PF.

HSPB5 Inhibition by NCI-41356 Reduces Experimental Lung Fibrosis by Blocking TGF-β1 Signaling

Idiopathic pulmonary fibrosis is a chronic, progressive and lethal disease of unknown etiology that ranks among the most frequent interstitial lung diseases. Idiopathic pulmonary fibrosis is characterized by dysregulated healing mechanisms that lead to the accumulation of large amounts of collagen in the lung tissue that disrupts the alveolar architecture. The two currently available treatments, nintedanib and pirfenidone, are only able to slow down the disease without being curative. We demonstrated in the past that HSPB5, a low molecular weight heat shock protein, was involved in the development of fibrosis and therefore was a potential therapeutic target. Here, we have explored whether NCI-41356, a chemical inhibitor of HSPB5, can limit the development of pulmonary fibrosis. In vivo, we used a mouse model in which fibrosis was induced by intratracheal injection of bleomycin. Mice were treated with NaCl or NCI-41356 (six times intravenously or three times intratracheally). Fibrosis was evaluated by collagen quantification, immunofluorescence and TGF-β gene expression. In vitro, we studied the specific role of NCI-41356 on the chaperone function of HSPB5 and the inhibitory properties of NCI-41356 on HSPB5 interaction with its partner SMAD4 during fibrosis. TGF-β1 signaling was evaluated by immunofluorescence and Western Blot in epithelial cells treated with TGF-β1 with or without NCI-41356. In vivo, NCI-41356 reduced the accumulation of collagen, the expression of TGF-β1 and pro-fibrotic markers (PAI-1, α-SMA). In vitro, NCI-41356 decreased the interaction between HSPB5 and SMAD4 and thus modulated the SMAD4 canonical nuclear translocation involved in TGF-β1 signaling, which may explain NCI-41356 anti-fibrotic properties. In this study, we determined that inhibition of HSPB5 by NCI-41356 could limit pulmonary fibrosis in mice by limiting the synthesis of collagen and pro-fibrotic markers. At the molecular level, this outcome may be explained by the effect of NCI-41356 inhibiting HSPB5/SMAD4 interaction, thus modulating SMAD4 and TGF-β1 signaling. Further investigations are needed to determine whether these results can be transposed to humans.

Senescent AECⅡ and the implication for idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) is a chronic and lethal lung disease with limited treatment options. The onset of IPF increases with age, indicating that aging is a major risk factor for IPF. Among the hallmarks of aging, cellular senescence is the primordial driver and primary etiological factor for tissue and organ aging, and an independent risk factor for the progression of IPF. In this review, we focus on the senescence of alveolar type II epithelial cells (AECIIs) and systematically summarize abnormal changes in signal pathways and biological process and implications of senescent AECIIs during IPF progression. Meanwhile, we objectively analyze current medications targeting the elimination of senescent cells or restoration of vitality such as senolytics, senomorphics, autophagy regulators, and stem cell therapy. Finally, we dialectically discuss the feasibility and limitation of targeting senescent AECIIs for IPF treatment. We hope that the understanding will provide new insights to the development of senescent AECII-based approaches for the prevention and mitigation of IPF.

KLF9 positively regulates TRIM33 to inhibit abnormal synovial fibroblast proliferation, migration as well as inflammation in rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) can cause irreversible joint injury and serious disability. This study aimed to investigate how TRIM33 regulated by KLF9 affects the aggressive behaviors of synovial fibroblasts induced by tumor necrosis factor-α (TNF-α).

MATERIALS AND METHODS

TNF-α-induced MH7A cells were used to simulate the in vitro model of RA. TRIM33 and KLF9 expression in TNF-α-challenged MH7A cells and transfection efficiency were analyzed via real-time reverse transcription polymerase chain reaction together with western blot. The viability, proliferation, invasion, and migration of TNF-α-induced MH7A cells after transfection was respectively detected by CCK-8, EdU staining, transwell, and wound-healing assays. The expression of invasion and migration-related proteins and inflammation-related proteins was determined by western blot and the levels of inflammatory factors were detected by enzyme-linked immunosorbent assay. The combination between TRIM33 and KLF9 was substantiated through dual-luciferase reporter assay and chromatin immunoprecipitation.

RESULTS

TRIM33 and KLF9 expression in TNF-α-challenged MH7A cells was downregulated. TRIM33 elevation inhibited TNF-α-elicited proliferation, metastasis as well as inflammation of MH7A cells. Moreover, KLF9 was combined with TRIM33 and KLF9 promoted transcription of TRIM33. The inhibitory effect of TRIM33 overexpression on proliferation, invasion and migration and inflammation of MH7A cells induced by TNF-α was alleviated by the downregulation of KLF9.

CONCLUSION

KLF9 positively regulates TRIM33 to suppress the abnormal MH7A cell proliferation, migration, and reduce inflammation upon exposure to TNF-α, which was reversed by inhibiting KLF9.

The gut-lung axis: Gut microbiota changes associated with pulmonary fibrosis in mouse models induced by bleomycin

The main objective of this study was to investigate the alterations in the gut microbiota (GM) of pulmonary fibrosis (PF) mice induced by bleomycin (BLM) with its underlying mechanisms. BLM was docked with the targets of TGF-β/SMAD and caspase-3 pathways using the molecular docking technique. HE staining and Masson staining were applied to observe the histopathological changes in the pulmonary tissues. Detection of the apoptotic signals was conducted by flow cytometry and TUNEL staining. The mRNA expression of targets involved in the TGF-β/SMAD and caspase-3 signaling pathways in lungs was determined by qPCR. Immunohistochemistry (IHC) assay was used to detect the expression levels of cleaved caspase-3 and BAX proteins in mice lung tissues. 16S rDNA sequencing analysis was used to investigate the changes of GM in the fecal samples of mice in each group. The results showed that the apoptosis rate of pulmonary cells in the BLM group distinctly increased, with the expression levels of crucial target pro-apoptotic gene caspase-3, BAX with the corresponding protein, cleaved caspase-3, BAX were apparently elevated. This was accompanied by a significant increase in pro-fibrotic targets level such as TGF-β, fibronectin, collagen I, and collagen III. The mechanisms of PF induced by BLM were related to apoptosis of lung tissue cells such as alveolar epithelial cells and destroyed alveolar structure and excessive production of extracellular matrix (ECM), which may be bound up with activating TGF-β/SMAD and caspase-3 pathways. As for the GM, it was found that, after BLM induced PF in mice, the micro ecological balance of the GM was destroyed; the distance of PCo1 and Pco2 was significantly elongated, and the relative abundance of some intestinal probiotics like Catenibacterium and Lactobacillus (L. johnsonii and L. gasseri) dramatically lowered while the relative abundance of Verrucomicrobiales and Enterobacteriales substantially increased. Therefore, GM changes associated with PF in mouse models induced by BLM and the concept of "gut-lung axis" might provide an optional therapeutic strategy for PF.

E3 ubiquitin ligase Trim33 ubiquitylates Annexin A2 to promote NF-κB induced skin inflammation in psoriasis

BACKGROUND

Tripartite motif-containing protein 33, a member of the TRIM E3 ligase family, is shown to be involved in tumorigenesis, cell proliferation and inflammation. Alteration of several TRIM family proteins in psoriatic epidermis has been shown to participate in psoriasis pathogenesis. However, little is known about Trim33 expression and its role in psoriasis.

OBJECTIVES

To examine the expression and biological roles of Trim33 in psoriatic process, with a focus on identifying its novel substrates in psoriatic keratinocytes.

METHODS

Gene expression of Trim33 in biopsies from psoriasis patients compared with healthy volunteers was analysed by quantitative real-time polymerase chain reaction (qPCR) and immunofluorescence (IF). Identification of Trim33 substrates were performed using immunoprecipitation combined with mass spectrometry. Protein expression and localization were assessed by immunoblotting and immunofluorescence. Expression of cytokines was analysed with qPCR.

RESULTS

qPCR and IF analysis revealed increased expression of Trim33 in psoriatic epidermis. Overexpression of Trim33 promoted the expression of psoriasis-related proinflammatory cytokines IL-6, IL-1β and NLRP3 inflammasome. Intriguingly, Trim33 induced lysine 63 (K63)-linked ubiquitination of Annexin A2 (Anxa2), which promoted its interaction with p50/p65 subunits of NF-κB, favoured the retention of p50/p65 in the nucleus and promoted the expression of inflammation-related NF-κB downstream genes.

CONCLUSIONS

Our study highlights the upregulation of Trim33 in psoriatic epidermis and its pivotal role in promoting the inflammation of keratinocytes by Anxa2/NF-κB pathway. Our findings imply that Trim33 might be further explored as potential target for psoriasis treatment.

The methyl-CpG-binding domain 2 facilitates pulmonary fibrosis by orchestrating fibroblast to myofibroblast differentiation

Although DNA methylation has been recognised in the pathogenesis of idiopathic pulmonary fibrosis (IPF), the exact mechanisms are yet to be fully addressed. Herein, we demonstrate that lungs originated from IPF patients and mice after bleomycin (BLM)-induced pulmonary fibrosis are characterised by altered DNA methylation along with overexpression in myofibroblasts of methyl-CpG-binding domain 2 (MBD2), a reader responsible for interpreting DNA methylome-encoded information. Specifically, depletion of Mbd2 in fibroblasts or myofibroblasts protected mice from BLM-induced pulmonary fibrosis coupled with a significant reduction of fibroblast differentiation. Mechanistically, transforming growth factor (TGF)-β1 induced a positive feedback regulatory loop between TGF-β receptor I (TβRI), Smad3 and Mbd2, and erythroid differentiation regulator 1 (Erdr1). TGF-β1 induced fibroblasts to undergo a global DNA hypermethylation along with Mbd2 overexpression in a TβRI/Smad3 dependent manner, and Mbd2 selectively bound to the methylated CpG DNA within the Erdr1 promoter to repress its expression, through which it enhanced TGF-β/Smad signalling to promote differentiation of fibroblast into myofibroblast and exacerbate pulmonary fibrosis. Therefore, enhancing Erdr1 expression strikingly reversed established pulmonary fibrosis. Collectively, our data support that strategies aimed at silencing Mbd2 or increasing Erdr1 could be viable therapeutic approaches for prevention and treatment of pulmonary fibrosis in clinical settings.

TGF-β1/Smad3 upregulates UCA1 to promote liver fibrosis through DKK1 and miR18a

TGF-β1 is the strongest cytokine known to promote liver fibrosis. It has been previously demonstrated that the activation of TGF-β1 initiates a temporary collagen accumulation program, which is important for wound repair in several organs. Furthermore, temporary extracellular matrix enhancement often leads to progressive fibrosis, which is accountable for cases of severe morbidity and mortality worldwide. However, its action mechanism has not been fully explored. It was previously reported that UCA1 could promote its occurrence and development in various tumors. Importantly, it was reported that TGF-β1 could activate the expression of UCA1 in liver cancer, gastric cancer, and breast cancer. However, the role of UCA1 in organ fibrosis, including liver fibrosis, remains unreported. The present study reported for the first time that TGF-β1/Smad3 could promote liver fibrosis by upregulating UCA1, which further affected DKK1 and collagen, such as COL1A1, COL1A2, and COL3A1. Meanwhile, UCA1 could competitively bind with miR18a to stabilize Smad3 to constitute a positive feedback pathway, which played a significant role in the promotion of liver fibrosis. Altogether, the present study provides a theoretical basis for devising promising treatment strategies for liver fibrosis. KEY MESSAGES : UCA1 was found to promote the progression of liver fibrosis in vitro. UCA1 is regulated by TGF-β1 and promotes liver fibrosis through the canonical Smad pathway. UCA1 can competitively bind with miR18a, promote liver fibrosis by stabilizing Smad3, and form a UCA1-miR18a/Smad3 positive feedback. UCA1 binds EZH2 to inhibit the DKK1 expression and promote liver fibrosis.

Identification of Hub Genes in Idiopathic Pulmonary Fibrosis and NSCLC Progression:Evidence From Bioinformatics Analysis

Background: Lung cancer is the most common comorbidity of idiopathic pulmonary fibrosis. Thus there is an urgent need for the research of IPF and carcinogenesis

Objective: The objective of this study was to explore hub genes which are common in pulmonary fibrosis and lung cancer progression through bioinformatic analysis.

Methods: All the analysis was performed in R software. Differentially expressed genes (DEGs) were explored by comparing gene expression profiles between IPF tissues and healthy lung tissues from GSE24206, GSE53845, GSE101286 and GSE110147 datasets. Venn Diagram analysis was used to identify the overlapping genes, while GO and KEGG pathway enrichment analysis were used to explore the biological functions of the DEGs using clusterprofiler package. Hub genes were identified by analyzing protein-protein interaction networks using Cytoscape software. Nomogram was constructed using the rms package. Tumor immune dysfunction and exclusion (TIDE) and Genomics of Drug Sensitivity in Cancer (GDSC) analysis was used to quantify the immunotherapy and chemotherapy sensitivity of non-small cell lung cancer (NSCLC) patients.

Results:COL1A1, COL3A1, MMP1, POSTN1 and TIMP3 were identified as the top five hub genes. The five hub genes were used to construct a diagnostic nomogram that was validated in another IPF dataset. Since the hub genes were also associated with lung cancer progression, we found that the nomogram also had diagnostic value in NSCLC patients. These five genes achieved a statistically difference of overall survival in NSCLC patients (p < 0.05). The expression of the five hub genes was mostly enriched in fibroblasts. Fibroblasts and the hub genes also showed significant ability to predict the susceptibility of NSCLC patients to chemotherapy and immunotherapy.

Conclusion: We identified five hub genes as potential biomarkers of IPF and NSCLC progression. This finding may give insight into the underlying molecular mechanisms of IPF and lung cancer progression and provides potential targets for developing new therapeutic agents for IPF patients.

The crystallin alpha B (HSPB5)-tripartite motif containing 33 (TRIM33) axis mediates myocardial fibrosis induced by angiotensinogen II through transforming growth factor-β (TGF-β1)-Smad3/4 signaling

Myocardial fibrosis, a common pathological manifestation of cardiac remodeling (CR), often leads to heart failure (HF) and even death. The underlying molecular mechanism of the role of TRIM33 in Ang II–induced myocardial fibrosis is not fully understood. We found that TRIM33 was specifically upregulated in CFs and myocardial tissue after Ang II stimulation. Adult mice induced by Ang II were used as in vivo models, and Ang II–induced neonatal mouse primary cardiac fibroblasts (CFs) were used as in vitro models. The level of CF fibrosis in vitro was assessed by CF proliferation, migration, activation and extracellular matrix (ECM) synthesis. In addition, Masson staining, the heart weight/body weight (HW/BW) ratio and echocardiography were used to evaluate the in vivo effect of TRIM33. TRIM33 expression was specifically upregulated in CFs and myocardial tissue after Ang II stimulation. In in vitro experiments, we found that TRIM33 knockdown promoted Ang II–induced CF proliferation, while TRIM33 overexpression weakened Ang II–induced CF proliferation, migration, activation and collagen synthesis. Mechanistically, we showed that TRIM33, negatively regulated by HSPB5, mediated its antifibrotic effect by inhibiting the activation of TGF-β1 and its downstream genes, Smad3 and Smad4. Finally, TRIM33 overexpression suppressed fibrosis and promoted cardiac repair and functional recovery in Ang II–induced mice. Our results clearly establish that TRIM33 limits cardiac fibrosis by hindering CF proliferation, migration, activation and collagen synthesis. Enhancing these beneficial functions of TRIM33 by a targeting vector might be a novel therapeutic strategy for CR.