The Inflammasome NLR Family Pyrin Domain-Containing Protein 3 (NLRP3) as a Novel Therapeutic Target for Idiopathic Pulmonary Fibrosis

Plasma genome-wide mendelian randomization identifies potentially causal genes in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a complex lung disease with a very poor prognosis. Existing drugs for the treatment of IPF are still insufficient. Therefore, there is still a need to explore new drug targets for preventing and treating IPF.

METHODS

We included quantitative trait loci (QTL) for genes, DNA methylation, and proteins in plasma, as well as the summary statistics for IPF. Genetic variants located within 500 kb of the gene and strongly associated with plasma exposure were used as instrumental variables. The causal association between plasma exposures and IPF was primarily estimated using summary-data-based Mendelian randomization (SMR) analysis. Five other MR methods and sensitivity analyses were employed to validate the SMR results. Bayesian tests for colocalization between QTL and IPF risk loci further strengthen the MR results.

RESULTS

We identified three genes and five DNA methylation sites causally associated with IPF by SMR analysis, validation of MR analysis, sensitivity analysis, and colocalization analysis. BTRC and LINC01252 were negatively associated with IPF risk (OR: 0.30, 95% CI: 0.17-0.54, FDRSMR = 0.029; OR: 0.85, 95% CI: 0.78-0.92, FDRSMR = 0.043), and RIPK4 was positively associated with IPF risk (OR: 2.60, 95% CI: 1.64-4.12, FDRSMR = 0.031). cg00045227 (OR8U8, OR: 1.16, 95% CI: 1.08-1.24, FDRSMR = 0.010), cg00577578 (GBAP1, OR: 1.23, 95% CI: 1.12-1.36, FDRSMR = 0.014), cg14222479 (ARPM1, OR: 3.17, 95% CI: 1.98-5.08, FDRSMR = 0.001), and cg19263494 (PMF1, OR: 1.20, 95% CI: 1.10-1.30, FDRSMR = 0.012) were positively associated with the risk of IPF, whereas cg07163735 (MAPT, OR: 0.22, 95% CI: 0.11-0.45, FDRSMR = 0.013) was negatively correlated with the risk of IPF.

CONCLUSIONS

This study demonstrated that genetically determined plasma levels of the BTRC, RIPK4, and LINC01252 genes, as well as methylation levels of cg00045227 (OR8U8), cg00577578 (GBAP1), cg07163735 (MAPT), cg14222479 (ARPM1), and cg19263494 (PMF1), have causal influences on the risk of IPF.

The involvement of HDAC3 in the pathogenesis of lung injury and pulmonary fibrosis

Acute lung injury (ALI) and its severe counterpart, acute respiratory distress syndrome (ARDS), are critical respiratory conditions with high mortality rates due primarily to acute and intense pulmonary inflammation. Despite significant research advances, effective pharmacological treatments for ALI and ARDS remain unavailable, highlighting an urgent need for therapeutic innovation. Notably, idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease characterized by the irreversible progression of fibrosis, which is initiated by repeated damage to the alveolar epithelium and leads to excessive extracellular matrix deposition. This condition is further complicated by dysregulated tissue repair and fibroblast dysfunction, exacerbating tissue remodeling processes and promoting progression to terminal pulmonary fibrosis. Similar to that noted for ALI and ARDS, treatment options for IPF are currently limited, with no specific drug therapy providing a cure. Histone deacetylase 3 (HDAC3), a notable member of the HDAC family with four splice variants (HD3α, -β, -γ, and -δ), plays multiple roles. HDAC3 regulates gene transcription through histone acetylation and adjusts nonhistone proteins posttranslationally, affecting certain mitochondrial and cytoplasmic proteins. Given its unique structure, HDAC3 impacts various physiological processes, such as inflammation, apoptosis, mitochondrial homeostasis, and macrophage polarization. This article explores the intricate role of HDAC3 in ALI/ARDS and IPF and evaluates its therapeutic potential the treatment of these severe pulmonary conditions.

Decidual Cells Block Inflammation-Mediated Inhibition of 15-Hydroxyprostaglandin Dehydrogenase in Trophoblasts

Chorioamnionitis generates prostaglandin (PG) E2 and F2α, promoting fetal membrane rupture, cervical ripening, and uterine contractions. 15-Hydroxyprostaglandin dehydrogenase (HPGD) contributes to pregnancy maintenance by inactivating PGs. Herein, the role of decidual cells in the regulation of HPGD expression at the maternal-fetal interface was investigated. HPGD immunostaining was primarily detected in anchoring villi and choriodecidual extravillous trophoblasts (EVTs) during pregnancy. Chorionic EVTs adjacent to the decidua parietalis exhibited significantly higher HPGD levels than those adjacent to the amnion. HPGD histologic score levels were significantly lower in choriodecidua from chorioamnionitis versus gestational age-matched controls (means ± SEM, 132.6 ± 3.8 versus 31.2 ± 7.9; P < 0.05). Conditioned media supernatant (CMS) from in vitro decidualized term decidual cells (TDCs) up-regulated HPGD levels in differentiated EVTs, primary trophoblasts, and HTR8/SVneo cells. However, CMS from 5 μg/mL lipopolysaccharide or 10 ng/mL IL-1β pretreated TDC cultures down-regulated HPGD levels in HTR8/SVneo cultures. Similarly, direct treatment of HTR8/SVneo with lipopolysaccharide or IL-1β significantly reduced HPGD levels versus control (P < 0.05) but not in TDC-CMS pretreated HTR8/SVneo cultures. Collectively, these results uncover a novel decidual cell-mediated paracrine mechanism that stimulates levels of trophoblastic HPGD, whose function is to inactivate labor-inducing PGs, thereby promoting uterine quiescence during pregnancy. However, infectious/inflammatory stimuli in decidual cells cause a paracrine inhibition of trophoblastic HPGD expression, increasing PGE2/PGF2α levels, thereby contributing to preterm birth.

Uncovering novel mechanisms of chitinase-3-like protein 1 in driving inflammation-associated cancers

Chitinase-3-like protein 1 (CHI3L1) is a secreted glycoprotein that is induced and regulated by multiple factors during inflammation in enteritis, pneumonia, asthma, arthritis, and other diseases. It is associated with the deterioration of the inflammatory environment in tissues with chronic inflammation caused by microbial infection or autoimmune diseases. The expression of CHI3L1 expression is upregulated in several malignant tumors, underscoring the crucial role of chronic inflammation in the initiation and progression of cancer. While the precise mechanism connecting inflammation and cancer is unclear, the involvement of CHI3L1 is involved in chronic inflammation, suggesting its role as a contributing factor to in the link between inflammation and cancer. CHI3L1 can aggravate DNA oxidative damage, induce the cancerous phenotype, promote the development of a tumor inflammatory environment and angiogenesis, inhibit immune cells, and promote cancer cell growth, invasion, and migration. Furthermore, it participates in the initiation of cancer progression and metastasis by binding with transmembrane receptors to mediate intracellular signal transduction. Based on the current research on CHI3L1, we explore introduce the receptors that interact with CHI3L1 along with the signaling pathways that may be triggered during chronic inflammation to enhance tumorigenesis and progression. In the last section of the article, we provide a brief overview of anti-inflammatory therapies that target CHI3L1.

The mitigating effect of para-hydroxycinnamic acid in bleomycin-induced pulmonary fibrosis in mice through targeting oxidative, inflammatory and fibrotic pathways

This study investigated the therapeutic benefits of para-hydroxycinnamic acid in mice with bleomycin-induced lung fibrosis. Forty male BALB/c mice were randomly assigned to four groups: normal, which received 0.9% normal saline; induced, which received a single dose of bleomycin (5 mg/kg) by oropharyngeal challenge; pirfenidone-treated; and para-hydroxycinnamic acid-treated, which challenged with bleomycin and received a daily oral dose of 300 and 50 mg/kg, respectively, from day 7 to day 21. Tissue pro-fibrotic and inflammatory cytokines, oxidative indicators, pulmonary histopathology, immunohistochemistry of fibrotic proteins and the assessment of gene expression by RT-qPCR were evaluated on day 22 after euthanizing animals. Pirfenidone and para-hydroxycinnamic acid managed to alleviate the fibrotic endpoints by statistically improving the weight index, histopathological score and reduced expression of fibrotic-related proteins in immune-stained lung sections, as well as fibrotic markers measured in serum samples. They also managed to alleviate tissue levels of oxidative stress and inflammatory and pro-fibrotic mediators. para-Hydroxycinnamic acid enhanced the expression of crucial genes associated with oxidative stress, inflammation and fibrosis in vivo. para-Hydroxycinnamic acid has demonstrated similar effectiveness to pirfenidone, suggesting it could be a promising treatment for fibrotic lung conditions by inhibiting the TGF-β1/Smad3 pathway or through its anti-inflammatory and antioxidant properties.

Vinpocetine alleviated alveolar epithelial cells injury in experimental pulmonary fibrosis by targeting PPAR-γ/NLRP3/NF-κB and TGF-β1/Smad2/3 pathways

This study aimed to investigate the potential anti-fibrotic activity of vinpocetine in an experimental model of pulmonary fibrosis by bleomycin and in the MRC-5 cell line. Pulmonary fibrosis was induced in BALB/c mice by oropharyngeal aspiration of a single dose of bleomycin (5 mg/kg). The remaining induced animals received a daily dose of pirfenidone (as a standard anti-fibrotic drug) (300 mg/kg/PO) and vinpocetine (20 mg/kg/PO) on day 7 of the induction till the end of the experiment (day 21). The results of the experiment revealed that vinpocetine managed to alleviate the fibrotic endpoints by statistically improving (P ≤ 0.05) the weight index, histopathological score, reduced expression of fibrotic-related proteins in immune-stained lung sections, as well as fibrotic markers measured in serum samples. It also alleviated tissue levels of oxidative stress and inflammatory and pro-fibrotic mediators significantly elevated in bleomycin-only induced animals (P ≤ 0.05). Vinpocetine managed to express a remarkable attenuating effect in pulmonary fibrosis both in vivo and in vitro either directly by interfering with the classical TGF-β1/Smad2/3 signaling pathway or indirectly by upregulating the expression of Nrf2 enhancing the antioxidant system, activating PPAR-γ and downregulating the NLRP3/NF-κB pathway making it a candidate for further clinical investigation in cases of pulmonary fibrosis.

MicroRNA transcriptome analysis reveals the immune regulatory mechanism of Crassostrea hongkongesis against Vibrio harveyi infection

MicroRNAs (miRNAs) are small non-coding RNA molecules that modulate target-genes expression and play crucial roles in post-transcriptional regulation and immune system regulation. The Hong Kong oyster (Crassostrea hongkongesis), as the main marine aquaculture shellfish in the South China Sea, not only has high economic and ecological value, but also is an ideal model for conducting research on pathogen host interaction. Vibrio harveyi, a Gram negative luminescent marine bacterium, is widely distributed in coastal water environments and can cause large-scale death of C. hongkongesis. However, little in formation is available on the immune regulatory mechanisms of C. hongkongesis infected with V. harveyi. Therefore, we performed microRNA transcriptome analysis for elucidating the immunoregulation mechanism of C. hongkongesis infected with V. harveyi. The results show that a total of 308468208 clean reads and 288371159 clean tags were obtained. 222 differentially expressed miRNAs were identified. A total of 388 target genes that were differentially expressed and negatively correlated with miRNA expression were predicted by 222 DEmiRs. GO enrichment analysis of 388 DETGs showed that they were mainly enriched in the immune-related term of membrane-bounded vesicle, endocytic vesicle lumen, antigen processing and presentation of exogenous peptide antigen via MHC class I, antigen processing and presentation of peptide antigen via MHC class I, and other immune-related term. KEGG enrichment analysis showed that DETGs were mainly enriched in the Complement and coagulation cascades, Herpes simplex virus 1 infection, Bacterial invasion of epithelial cells, Antigen processing and presentation and NOD-like receptor signaling pathway. The 16 key DEmiRs and their target genes form a regulatory network for seven immune-related pathways. These results suggest that V. harveyi infection induces a complex miRNA response with wide-ranging effects on immune gene expression in the C. hongkongesis. This study explored the immune response of C. hongkongesis to V. harveyi infection at the level of miRNAs, which provides new ideas for the healthy culture and selective breeding of C. hongkongesis.

Linking NLRP3 inflammasome and pulmonary fibrosis: mechanistic insights and promising therapeutic avenues

Pulmonary fibrosis is a devastating disorder distinguished by redundant inflammation and matrix accumulation in the lung interstitium. The early inflammatory cascade coupled with recurring tissue injury orchestrates a set of events marked by perturbed matrix hemostasis, deposition of matrix proteins, and remodeling in lung tissue. Numerous investigations have corroborated a direct correlation between the NLR family pyrin domain-containing 3 (NLRP3) activation and the development of pulmonary fibrosis. Dysregulated activation of NLRP3 within the pulmonary microenvironment exacerbates inflammation and may incite fibrogenic responses. Nevertheless, the precise mechanisms through which the NLRP3 inflammasome elicits pro-fibrogenic responses remain inadequately defined. Contemporary findings suggest that the pro-fibrotic consequences stemming from NLRP3 signaling primarily hinge on the action of interleukin-1β (IL-1β). IL-1β instigates IL-1 receptor signaling, potentiating the activity of transforming growth factor-beta (TGF-β). This signaling cascade, in turn, exerts influence over various transcription factors, including SNAIL, TWIST, and zinc finger E-box-binding homeobox 1 (ZEB 1/2), which collectively foster myofibroblast activation and consequent lung fibrosis. Here, we have connected the dots to illustrate how the NLRP3 inflammasome orchestrates a multitude of signaling events, including the activation of transcription factors that facilitate myofibroblast activation and subsequent lung remodeling. In addition, we have highlighted the prominent role played by various cells in the formation of myofibroblasts, the primary culprit in lung fibrosis. We also provided a concise overview of various compounds that hold the potential to impede NLRP3 inflammasome signaling, thus offering a promising avenue for the treatment of pulmonary fibrosis.

Pyroptosis-related signatures predict immune characteristics and prognosis in IPF

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

Betanin protects against bleomycin-induced pulmonary fibrosis by regulating the NLRP3/IL-1β/TGF-β1 pathway-mediated epithelial-to-mesenchymal transition

Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease that leads to dyspnea and progressive loss of lung function. This study aimed to investigate the protective effect of betanin (BET), the major pigment in red beetroot, on pulmonary fibrosis induced by bleomycin (BLM) in rats and to assess the underlying mechanisms. In this view, total and differential cell counts and LDH activity in bronchoalveolar lavage fluid were estimated. Furthermore, MDA and GSH contents in the lungs were colorimetrically measured, while hydroxyproline, NLRP3, ASC, caspase-1, TGF-β1, and vimentin levels in lung tissue were evaluated using the ELISA technique. Moreover, IL-1β, E-cadherin, and α-SMA expressions were analyzed by immunostaining of lung specimens. BET treatment protects against pulmonary fibrosis as indicated by the reduction in total and differential cell counts, LDH activity, hydroxyproline, NLRP3, ASC, caspase-1, IL-1β, and TGF-β1 levels. MDA content was also decreased following BET administration, while GSH content was elevated. Additionally, BET suppressed the EMT process as evidenced by an increase in E-cadherin expression besides the reduction in vimentin and α-SMA expressions. To conclude, these results revealed the protective effect of BET against pulmonary fibrosis that might be attributed to the attenuation of the NLRP3/IL-1β/TGF-β1 signaling pathway and EMT process.

NXC736 Attenuates Radiation-Induced Lung Fibrosis via Regulating NLRP3/IL-1β Signaling Pathway

Radiation-induced lung fibrosis (RILF) is a common complication of radiotherapy in lung cancer. However, to date no effective treatment has been developed for this condition. NXC736 is a novel small-molecule compound that inhibits NLRP3, but its effect on RILF is unknown. NLRP3 activation is an important trigger for the development of RILF. Thus, we aimed to evaluate the therapeutic effect of NXC736 on lung fibrosis inhibition using a RILF animal model and to elucidate its molecular signaling pathway. The left lungs of mice were irradiated with a single dose of 75 Gy. We observed that NXC736 treatment inhibited collagen deposition and inflammatory cell infiltration in irradiated mouse lung tissues. The damaged lung volume, evaluated by magnetic resonance imaging, was lower in NXC736-treated mice than in irradiated mice. NXC736-treated mice exhibited significant changes in lung function parameters. NXC736 inhibited inflammasome activation by interfering with the NLRP3-ASC-cleaved caspase-1 interaction, thereby reducing the expression of IL-1β and blocking the fibrotic pathway. In addition, NXC736 treatment reduced the expression of epithelial-mesenchymal transition markers such as α-SMA, vimentin, and twist by blocking the Smad 2,3,4 signaling pathway. These data suggested that NXC736 is a potent therapeutic agent against RILF.

Rutin alleviates ventilator-induced lung injury by inhibiting NLRP3 inflammasome activation

Whether rutin relieves ventilator-induced lung injury (VILI) remains unclear. Here, we used network pharmacology, bioinformatics, and molecular docking to predict the therapeutic targets and potential mechanisms of rutin in the treatment of VILI. Subsequently, a mouse model of VILI was established to confirm the effects of rutin on VILI. HE staining showed that rutin alleviated VILI. TUNEL staining showed that rutin reduced apoptosis in the lung tissue of mice with VILI, and the same change was observed in the ratio of Bax/Bcl2. Furthermore, rutin reduced the expression of NLRP3, ASC, Caspase1, IL1β, and IL18 in the lung tissues of mice with VILI. Mechanistically, rutin suppressed the TLR4/NF-κB-P65 pathway, which promoted the M1 to M2 macrophage transition and alleviated inflammation in mice with VILI. Rutin relieved NLRP3 inflammasome activation by regulating M1/M2 macrophage polarization and inhibiting the activation of the TLR4/NF-κB-P65 pathway, resulting in the amelioration of VILI in mice.

GATA6 promotes fibrotic repair of tracheal injury through NLRP3 inflammasome-mediated epithelial pyroptosis

Tracheal injury is a challenging emergency condition that is characterized by the abnormal repair of the trachea. GATA6, a well-established transcription factor, plays a crucial role in tissue injury and epithelial regenerative repair. This study aims to evaluate the role of GATA6 in NF-κB-mediated NLRP3 inflammasome activation and pyroptosis after tracheal injury. Tracheal tissues and serum samples were collected from clinical patients and a rat model of tracheal injury. Upon GATA6 knockdown or overexpression, BEAS-2B and rat tracheal epithelial (RTE) cells were treated with lipopolysaccharides and nigericin before being co-cultured with primary tracheal fibroblasts. The changes of NLRP3 inflammasome activation and pyroptosis and their underlying mechanisms were detected. Additionally, the role of GATA6 downregulation in tracheal injury was verified in rats. GATA6 expression and NLRP3 inflammasome activation were upregulated following tracheal injury in the epithelium of granulation tissues. GATA6 silencing inhibited NLRP3 priming, NLRP3 inflammasome activation, and pyroptosis in BEAS-2B and RTE cells. Mechanistically, GATA6 was determined to have bound to the promoter region of NLRP3 and synergistically upregulated NLRP3 promoter activity with NF-κB. Furthermore, GATA6 overexpression promoted epithelial-mesenchymal transition via modulating the NF-κB/NLRP3 pathway. Epithelial NLRP3 inflammasome activation triggered ECM production in fibroblasts, which was suppressed by GATA6 knockdown and induced by GATA6 overexpression. Finally, the downregulation of GATA6 alleviated NLRP3 inflammasome-mediated pyroptosis induced by tracheal injury in rats, thereby reducing tracheal stenosis, inflammation, and fibrosis. GATA6 promotes fibrotic repair in tracheal injury through NLRP3 inflammasome-mediated epithelial pyroptosis, making it a potential biological therapeutic target for tracheal injury.

Advances in the Use of N-Acetylcysteine in Chronic Respiratory Diseases

N-acetylcysteine (NAC) is widely used because of its mucolytic effects, taking part in the therapeutic protocols of cystic fibrosis. NAC is also administered as an antidote in acetaminophen (paracetamol) overdosing. Thanks to its wide antioxidative and anti-inflammatory effects, NAC may also be of benefit in other chronic inflammatory and fibrotizing respiratory diseases, such as chronic obstructive pulmonary disease, bronchial asthma, idiopathic lung fibrosis, or lung silicosis. In addition, NAC exerts low toxicity and rare adverse effects even in combination with other treatments, and it is cheap and easily accessible. This article brings a review of information on the mechanisms of inflammation and oxidative stress in selected chronic respiratory diseases and discusses the use of NAC in these disorders.

Regulatory Cues in Pulmonary Fibrosis-With Emphasis on the AIM2 Inflammasome

Pulmonary fibrosis (PF) is a chronic lung disorder characterized by the presence of scarred and thickened lung tissues. Although the Food and Drug Administration approved two antifibrotic drugs, pirfenidone, and nintedanib, that are currently utilized for treating idiopathic PF (IPF), the clinical therapeutic efficacy remains unsatisfactory. It is crucial to develop new drugs or treatment schemes that combine pirfenidone or nintedanib to achieve more effective outcomes for PF patients. Understanding the complex mechanisms underlying PF could potentially facilitate drug discovery. Previous studies have found that the activation of inflammasomes, including nucleotide-binding and oligomerization domain (NOD)-like receptor protein (NLRP)1, NLRP3, NOD-like receptor C4, and absent in melanoma (AIM)2, contributes to lung inflammation and fibrosis. This article aims to summarize the cellular and molecular regulatory cues that contribute to PF with a particular emphasis on the role of AIM2 inflammasome in mediating pathophysiologic events during PF development. The insights gained from this research may pave the way for the development of more effective strategies for the prevention and treatment of PF.

Identification and immunological characterization of cuproptosis-related molecular clusters in idiopathic pulmonary fibrosis disease

Background

Idiopathic pulmonary fibrosis (IPF) has attracted considerable attention worldwide and is challenging to diagnose. Cuproptosis is a new form of cell death that seems to be associated with various diseases. However, whether cuproptosis-related genes (CRGs) play a role in regulating IPF disease is unknown. This study aims to analyze the effect of CRGs on the progression of IPF and identify possible biomarkers.

Methods

Based on the GSE38958 dataset, we systematically evaluated the differentially expressed CRGs and immune characteristics of IPF disease. We then explored the cuproptosis-related molecular clusters, the related immune cell infiltration, and the biological characteristics analysis. Subsequently, a weighted gene co-expression network analysis (WGCNA) was performed to identify cluster-specific differentially expressed genes. Lastly, the eXtreme Gradient Boosting (XGB) machine-learning model was chosen for the analysis of prediction and external datasets validated the predictive efficiency.

Results

Nine differentially expressed CRGs were identified between healthy and IPF patients. IPF patients showed higher monocytes and monophages M0 infiltration and lower naive B cells and memory resting T CD4 cells infiltration than healthy individuals. A positive relationship was found between activated dendritic cells and CRGs of LIPT1, LIAS, GLS, and DBT. We also identified cuproptosis subtypes in IPF patients. Go and KEGG pathways analysis demonstrated that cluster-specific differentially expressed genes in Cluster 2 were closely related to monocyte aggregation, ubiquitin ligase complex, and ubiquitin-mediated proteolysis, among others. We also constructed an XGB machine model to diagnose IPF, presenting the best performance with a relatively lower residual and higher area under the curve (AUC= 0.700) and validated by external validation datasets (GSE33566, AUC = 0.700). The analysis of the nomogram model demonstrated that XKR6, MLLT3, CD40LG, and HK3 might be used to diagnose IPF disease. Further analysis revealed that CD40LG was significantly associated with IPF.

Conclusion

Our study systematically illustrated the complicated relationship between cuproptosis and IPF disease, and constructed an effective model for the diagnosis of IPF disease patients.

Mirtazepine, an atypical antidepressant, mitigates lung fibrosis by suppressing NLPR3 inflammasome and fibrosis-related mediators in endotracheal bleomycin rat model

Idiopathic pulmonary fibrosis (IPF) is a progressive and irreversible lung disease with a poor prognosis. There is currently no definitive cure for IPF. The present study establishes a platform for the development of a novel therapeutic approach for the treatment of PF using the atypical antidepressant, mirtazapine. In the endotracheal bleomycin rat model, mirtazapine interfered with the activation of NLRP3 inflammasome via downregulating the NLRP3 on the gene and protein expression levels. Accordingly, the downstream mediators IL-1β and IL-18 were repressed. Such observation is potentially a direct result of the reported improvement in oxidative stress. Additionally, mirtazapine corrected the bleomycin-induced disparities in the levels of the fibrogenic mediators TGF-β, PDGF-BB, and TIMP-1, in consequence, the lung content of hydroxyproline and the expression of α-SMA were reduced. Besides, mirtazapine curbed the ICAM-1 and the chemotactic cytokines MCP-1 and CXCL4. This protective property of mirtazapine resulted in improving the BALF total and differential cell counts, diminishing LDH activity, and reducing the BALF total protein. Moreover, the inflammation and fibrosis scores were accordingly lower. To conclude, we reveal for the first time the efficacy of mirtazapine as a potential treatment for PF. The combination of social isolation, sleep problems, breathing difficulties, and fear of death can lead to psychological distress and depression in patients with IPF. Hence, mirtazapine is a promising treatment option that may improve the prognosis for IPF patients due to its antifibrotic effects, as well as its ability to alleviate depressive episodes.

YAP1 protects against PM2.5-induced lung toxicity by suppressing pyroptosis and ferroptosis

Pollution from fine particulate matter (PM2.5) has become a major threat to public health and has been related to lung toxicity. One of the key regulators of the Hippo signaling system, Yes-associated protein 1 (YAP1), is speculated to play a role in ferroptosis development. Here, we focused on investigating the function of YAP1 in pyroptosis and ferroptosis, aiming to explore its therapeutic potential in PM2.5-induced lung toxicity. PM2.5-induced lung toxicity was induced in Wild-type WT and conditional YAP1-knockout mice, and lung epithelial cells were stimulatd by PM2.5 in vitro. We used western blot, transmission electron microscopy, and fluorescence microscopy to investigate pyroptosis- and ferroptosis-related characteristics. We found that PM2.5 leads to lung toxicity using mechanisms involving pyroptosis and ferroptosis. YAP1 knockdown impeded pyroptosis, ferroptosis, and PM2.5-induced lung damage, as shown by increased histopathology, higher levels of proinflammatory cytokines, GSDMD protein, lipid peroxidation, and iron accumulation, as well as increased NLRP3 inflammasome activation and decreased SLC7A11 expression. YAP1 silencing consistently promoted NLRP3 inflammasome activation and reduced SLC7A11 levels, aggravating PM2.5-induced cellular damage. In contrast, YAP1-overexpressing cells inhibited NLRP3 inflammasome activation and increased SLC7A11 levels, preventing pyroptosis and ferroptosis. Overall, our data suggest that YAP1 ameliorates PM2.5-induced lung injury by inhibiting NLRP3-mediated pyroptosis and SL7A11-dependent ferroptosis.

Perspectives of PDE inhibitor on treating idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease (ILD) without an identifiable cause. If not treated after diagnosis, the average life expectancy is 3-5 years. Currently approved drugs for the treatment of IPF are Pirfenidone and Nintedanib, as antifibrotic drugs, which can reduce the decline rate of forced vital capacity (FVC) and reduce the risk of acute exacerbation of IPF. However these drugs can not relieve the symptoms associated with IPF, nor improve the overall survival rate of IPF patients. We need to develop new, safe and effective drugs to treat pulmonary fibrosis. Previous studies have shown that cyclic nucleotides participate in the pathway and play an essential role in the process of pulmonary fibrosis. Phosphodiesterase (PDEs) is involved in cyclic nucleotide metabolism, so PDE inhibitors are candidates for pulmonary fibrosis. This paper reviews the research progress of PDE inhibitors related to pulmonary fibrosis, so as to provide ideas for the development of anti-pulmonary fibrosis drugs.

Russian Registry of Idiopathic Pulmonary Fibrosis: Clinical Features, Treatment Management, and Outcomes

A registry of patients with idiopathic pulmonary fibrosis (IPF) was founded in Russia in 2016. The aim of this study was to analyze the demographic, clinical, functional, radiological, and morphological data of the patients included in this registry.

METHODS

This was a prospective multicenter, observational, non-interventional study. Patients' risk factors, demographics, clinical data, results of high-resolution computed tomography (HRCT) of the chest and pulmonary function testing, and lung tissue biopsy findings were analyzed. We also analyzed the exercise tolerance (6-min walking test) of patients, serological markers of systemic connective tissue diseases, treatment, clinical course, and outcomes of the disease. Multidisciplinary discussion (MDD) was used as needed.

RESULTS

One thousand three hundred and fifty-three patients were included in the registry from 2016 to 2020. The mean age was 64.4 ± 10.7 years, most patients were active smokers or ex-smokers. Antifibrotic therapy was administered to 90 of 948 patients (9.5%). Since starting the registry in 2016, the incidences of IPF have increased and the time period from manifestation of the disease to making the diagnosis has shortened, the number of patients on antifibrotic therapy has increased and the number of patients taking systemic steroids decreased.

CONCLUSION

The registry of patients with IPF was helpful to improve IPF diagnosis and to implement antifibrotic agents in clinical practice. Further analysis of the clinical course and prognostic markers of IPF in the Russian population is needed. An analysis of the long-term efficacy of antifibrotic therapy in this population is also important.

The Effects of Curcumin on Inflammasome: Latest Update

Curcumin, a traditional Chinese medicine extracted from natural plant rhizomes, has become a candidate drug for the treatment of different diseases due to its anti-inflammatory, anticancer, antioxidant, and antibacterial activities. Curcumin is generally beneficial to improve human health with anti-inflammatory and antioxidative properties as well as antitumor and immunoregulatory properties. Inflammasomes are NLR family, pyrin domain-containing 3 (NLRP3) proteins that are activated in response to a variety of stress signals and that promote the proteolytic conversion of pro-interleukin-1β and pro-interleukin-18 into active forms, which are central mediators of the inflammatory response; inflammasomes can also induce pyroptosis, a type of cell death. The NLRP3 protein is involved in a variety of inflammatory pathologies, including neurological and autoimmune disorders, lung diseases, atherosclerosis, myocardial infarction, and many others. Different functional foods may have preventive and therapeutic effects in a wide range of pathologies in which inflammasome proteins are activated. In this review, we have focused on curcumin and evidenced its therapeutic potential in inflammatory diseases such as neurodegenerative diseases, respiratory diseases, and arthritis by acting on the inflammasome.

Optimizing antidotal treatment with the oral HSP90 inhibitor TAS-116 against hydrochloric acid-induced pulmonary fibrosis in mice

Exposure to high concentrations of hydrochloric acid (HCl) can lead to severe acute and chronic lung injury. In the aftermath of accidental spills, victims may be treated for the acute symptoms, but the chronic injury is often overlooked. We have developed a mouse model of acute and chronic lung injury, in which the peak of acute lung injury occurs on the day 4 after HCl exposure. We have also demonstrated that HSP90 inhibitors are effective antidotes when administered starting 24 h after HCl. In this study we examined the hypothesis that the novel oral HSP90 inhibitor TAS-116 can effectively ameliorate HCl-induced lung injury even when treatment starts at the peak of the acute injury, as late as 96 h after HCl. C57BI/6J mice were intratracheally instilled with 0.1N HCl. After 24 or 96 h, TAS-116 treatment began (3.5, 7 or 14 mg/kg, 5 times per week, p. o.) for either 2,3 or 4 or weeks. TAS-116 moderated the HCl-induced alveolar inflammation, as reflected in the reduction of white blood cells and total protein content in bronchoalveolar lavage fluid (BALF), overexpression of NLRP3 inflammasome, and inhibited the activation of pro-fibrotic pathways. Furthermore, TAS-116 normalized lung mechanics and decreased the deposition of extracellular matrix proteins in the lungs of mice exposed to HCl. Delayed and shortened treatment with TAS-116, successfully blocked the adverse chronic effects associated with acute exposure to HCl.

Pyroptosis and respiratory diseases: A review of current knowledge

Pyroptosis is a relatively newly discovered programmed cell death accompanied by an inflammatory response. In the classical view, pyroptosis is mediated by caspases-1,-4,-5,-11 and executed by GSDMD, however, recently it was demonstrated that caspase-3 and-8 also participate in the process of pyroptosis, by cleaving GSDMD/E and GSDMD respectively. Different from autophagy and apoptosis, many pores are formed on the cell membrane during pyroptosis, which makes the cell membrane lose its integrity, eventually leading to the release of cytokines interleukin(IL)-1β and IL-18. When the body is infected with pathogens or exposed to some stimulations, pyroptosis could play an immune defense role. It is found that pyroptosis exists widely in infectious and inflammatory respiratory diseases such as acute lung injury, bronchial dysplasia, chronic obstructive pulmonary disease, and asthma. Excessive pyroptosis may accompany airway inflammation, tissue injury, and airway damage, and induce an inflammatory reaction, leading to more serious damage and poor prognosis of respiratory diseases. This review summarizes the relationship between pyroptosis and related respiratory diseases.