HIF-1α regulates EMT via the Snail and β-catenin pathways in paraquat poisoning-induced early pulmonary fibrosis

Metabolic landscape of human alveolar type II epithelial cells undergoing epithelial-mesenchymal transition induced directly by silica exposure

Epithelial-mesenchymal transition (EMT) plays an irreplaceable role in the development of silicosis. However, molecular mechanisms of EMT induced by silica exposure still remain to be addressed. Herein, metabolic profiles of human alveolar type II epithelial cells (A549 cells) exposed directly to silica were characterized using non-targeted metabolomic approaches. A total of 84 differential metabolites (DMs) were identified in silica-treated A549 cells undergoing EMT, which were mainly enriched in metabolisms of amino acids (e.g., glutamate, alanine, aspartate), purine metabolism, glycolysis, etc. The number of DMs identified in the A549 cells obviously increased with the elevated exposure concentration of silica. Remarkably, glutamine catabolism was significantly promoted in the silica-treated A549 cells, and the levels of related metabolites (e.g., succinate) and enzymes (e.g., α-ketoglutarate (α-KG) dehydrogenase) were substantially up-regulated, with a preference to α-KG pathway. Supplementation of glutamine into the cell culture could substantially enhance the expression levels of both EMT-related markers and Snail (zinc finger transcription factor). Our results suggest that the EMT of human alveolar epithelial cells directly induced by silica can be essential to the development of silicosis.

Interleukin-9 promotes EMT-mediated PM2.5-induced pulmonary fibrosis by activating the STAT3 pathway

This study investigated the impact of PM2.5 on promoting EMT in PM2.5-induced pulmonary fibrosis (PF) development and explored molecular mechanisms of the IL-9/STAT3/Snail/TWIST1 signaling pathway in PF owing to PM2.5. Four groups of male SD rats were formed: control (0 mg/kg.bw), low (1 mg/kg.bw), medium (5 mg/kg.bw), and high-dose (25 mg/kg.bw) PM2.5 groups. Experimental rats were subjected to PM2.5 exposure via intratracheal instillation, given once weekly for 16 weeks. 24 h after the final exposure, blood, BALF, and lung tissues were collected. Pulmonary epithelial cells underwent cultivation and exposure to varying PM2.5 concentrations with/without inhibitors for 24 h, after which total protein was extracted for relevant protein assays. The findings demonstrated that PM2.5 damaged lung tissue to different degrees and led to PF in rats. Rats subjected to PM2.5 exposure exhibited elevated concentrations of IL-9 protein in both serum and BALF, and elevated levels of IL-9 and its receptor, IL-9R, in lung tissues, compared to control counterparts. Furthermore, PM2.5-exposed groups demonstrated significantly augmented protein levels of p-STAT3, Snail, TWIST1, Vimentin, COL-I, and α-SMA, while displaying notably diminished levels of E-Cadherin compared to control group. The same findings were observed in PM2.5-treated cells. In BEAS-2B cells co-treated with Stattic (STAT3 inhibitor) and PM2.5, the opposite results occurred. Similar results were obtained for cells co-treated with IL-9-neutralizing antibody and PM2.5. Our findings suggest PM2.5 mediates PF development by promoting IL-9 expression, leading to STAT3 phosphorylation and upregulation of Snail and TWIST1 expression, triggering EMT occurrence and progression in lung epithelial cells.

The role of HIF-1α/BNIP3/mitophagy in acrylonitrile-induced neuronal death in HT22 cells and mice: A potential neuroprotection target

Acrylonitrile (AN) is a widely utilized organic compound in the production of diverse industrial synthetic materials. While acute exposure to AN can cause neurotoxicity, the precise mechanism remains unclear. Hypoxia-inducible factor 1 alpha (HIF-1α) is a pivotal transcription factor that coordinates and orchestrates multiple physiological processes to adapt to hypoxic conditions, ensuring cellular survival and homeostasis. In this study, we used in vitro (cultured mouse hippocampal neuronal cell line, HT22) and in vivo (AN exposed mice) approaches to investigate the potential modulator effects of HIF-1α in AN-induced neurotoxicity. In vitro, AN exposure caused concentration-dependent toxicity in HT22 cells, which was paralleled by increased Bax levels while decreasing Bcl-2. Exposure to AN resulted in reduced protein levels of HIF-1α, Bcl-2 19-kDa interacting protein 3 (BNIP3), microtubule-associated protein 1 light chain 3 beta (LC3B) and Beclin1, while increased the protein levels of the translocase of outer mitochondrial membrane 20 (TOM20). Furthermore, mitochondrial morphology and function were compromised, suggesting that AN impaired HIF-1α/BNIP3-mediated mitochondrial autophagy and promoted apoptosis. Treatment with a HIF-1α activator, cobalt chloride (CoCl2), reversed these effects, while pretreatment with a HIF-1α inhibitor, 2-methoxyestradiol (2-MeOE2), augmented them. In BNIP3 overexpressing HT22 cells, enhanced cell viability and reduced apoptosis rates were observed. Furthermore, the HIF-1α/BNIP3 pathway was activated by the prolyl hydroxylase (PHD2) inhibitor, deferoxamine (DFO), which increased HT22 cell viability. Similarly, the activation of HIF-1α by administering 20 mg/kg of CoCl2 was found to alleviate neurotoxicity in mice. This treatment enhanced elevations of autophagy protein expression and co-localization of BNIP3 and LC3B. In summary, under normoxia, AN induced neurotoxicity by promoting PHD2-mediated HIF-1α degradation, disrupted the BNIP3-mediated mitophagy pathway, and enhanced apoptosis. Our findings underscore the effect of the HIF-1α/BNIP3-mediated mitochondrial autophagy in AN-induced neurotoxicity and suggest potential therapeutic strategies involving HIF-1α activation or BNIP3 overexpression for AN poisoning treatment.

Integrin-β1 aggravates paraquat-induced pulmonary fibrosis by activation of FAK/ ERK1/2 pathway depending on fibrotic ECM

BACKGROUND

Irreversible pulmonary fibrosis induced by paraquat is the most prevalent cause of death in patients with paraquat poisoning. Pulmonary fibrosis is characterized by abnormal deposition of extracellular matrix (ECM). Currently, the role of fibrotic ECM microenvironment in paraquat-induced pulmonary fibrosis has not been established.

METHODS

Rat pulmonary fibrosis model was induced by paraquat, ATN-161 (an integrin-β1 antagonist) was given to investigate their effect on Rat survival and pulmonary fibrosis. Lungs were decellularized to generate normal and fibrotic acellular ECM scaffolds using Triton and SDS. Fibroblasts were cocultured with ECM scaffolds to established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts. Then we explored the effect of fibrotic ECM microenvironment systematically promoting on integrin-β1/FAK/ERK1/2 pathway and established 3D culture systems to investigate the relationship between fibrotic ECM and the differentiation of fibroblasts.

RESULTS

Antagonism of integrin-β1 could alleviate paraquat-induced pulmonary fibrosis and ameliorate survival status of rats. Compared to normal ECM, fibrotic extracellular microenvironment promoted the differentiation of fibroblasts to myofibroblasts. Antagonism of integrin-β1 could also ameliorate the promotion of fibrotic extracellular microenvironment on differentiation of fibroblasts to myofibroblasts. Fibrotic ECM microenvironment promotes fibroblasts transforming into myofibroblasts through integrin-β1/FAK/ERK1/2 signaling pathway. Moreover, this phenomenon holds independent on exogenous integrin-β1.

CONCLUSIONS

Activation of integrin-β1/FAK/ERK1/2 pathway aggravates paraquat-induced pulmonary fibrosis depend on fibrotic ECM and integrin-β1 may be a prospective therapeutic target for paraquat-induced pulmonary fibrosis in the future.

Integrative analysis of the efficacy and pharmacological mechanism of Xuefu Zhuyu decoction in idiopathic pulmonary fibrosis via evidence-based medicine, bioinformatics, and experimental verification

Objective

We used evidence-based medicine, bioinformatics and experimental verification to comprehensively analyze the efficacy and pharmacological mechanism of Xuefu Zhuyu decoction (XFZYD) in the treatment of idiopathic pulmonary fibrosis (IPF).

Methods

Major databases were retrieved for randomized controlled trials (RCTs) of XFZYD treating IPF to perform meta-analysis. Active ingredients and target genes of XFZYD were identified from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). IPF-related differentially expressed genes (DEGs) were identified from the Gene Expression Omnibus (GEO) database. The RGUI software was utilized for Gene Ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The ingredient-target and protein-protein interaction (PPI) networks were achieved through Cytoscape software and the STRING database to identify the key compounds and target proteins. Molecular docking was performed using AutoDockTool and AutoDock Vina software. The effect between key compounds and target proteins was verified in animal experiments.

Results

Six RCTs were included for meta-analysis, which uncovered that the total effective rate of clinical efficacy was higher in the experimental group than control group. Then, 156 active ingredients and 254 target genes of XFZYD, and 1,566 IPF-related DEGs were identified. The intersection analysis identified 48 target genes correlating with 130 active ingredients of XFZYD treating IPF. GO functional enrichment, KEGG pathway enrichment, ingredient-target network and PPI network were achieved. Following the identification of key compounds and target proteins, we performed molecular docking. Ultimately, our research focused on the key compound quercetin for experimental validation to assess its interactions with two key target proteins, JUN and PTGS2.

Conclusion

The effectiveness of XFZYD on IPF has been substantiated through evidence-based medicine. The pharmacological mechanism of XFZYD for IPF treatment involves a complex interplay of various compounds and targets, with quercetin exerting pronounced impacts on JUN and PTGS2 proteins.

A spotlight on the role of copper in the epithelial to mesenchymal transition

The complex process known as epithelial to mesenchymal transition (EMT) plays a fundamental role in several biological settings, encompassing embryonic development, wound healing, and pathological conditions such as cancer and fibrosis. In recent years, a bulk of research has brought to light the key role of copper, a trace element with essential functions in cellular metabolism, cancer initiation and progression. Indeed, copper, besides functioning as cofactor of enzymes required for essential cellular processes, such as energy production and oxidation reactions, has emerged as an allosteric regulator of kinases whose activity is required to fulfill cancer dissemination through the EMT. In this comprehensive review, we try to describe the intricate relationship between the transition metal copper and EMT, spanning from the earliest foundational studies to the latest advancements. Our aim is to shed light on the multifaceted roles undertaken by copper in EMT in cancer and to unveil the diverse mechanisms by which copper homeostasis exerts its influence over EMT regulators, signaling pathways, cell metabolic reprogramming and transcription factors ultimately contributing to the spread of cancer. Therefore, this review not only may contribute to a deeper comprehension of copper-mediated mechanisms in EMT but also supports the hypothesis that targeting copper may contribute to counteract the progression of EMT-associated pathologies.

Triple negative breast cancer cells exposed to aryl hydrocarbon receptor ligands hexachlorobenzene and chlorpyrifos activate endothelial cells

Breast cancer is currently one of the most prevalent cancers worldwide. The mechanisms by which pesticides can increase breast cancer risk are multiple and complex. We have previously observed that two aryl hydrocarbon receptor (AhR) agonists ‒pesticides hexachlorobenzene (HCB) and chlorpyrifos (CPF)‒ act on tumor progression, stimulating cell migration and invasion in vitro and tumor growth in animal models. Elevated levels of hypoxia inducible factor-1α (HIF-1α) are found in malignant breast tumors, and HIF-1α is known to induce proangiogenic factors such as vascular endothelial growth factor (VEGF), nitric oxide synthase-2 (NOS-2) and cyclooxygenase-2 (COX-2), which are fundamental in breast cancer progression. In this work, we studied HCB (0.005, 0.05, 0.5 and 5 μM) and CPF (0.05, 0.5, 5 and 50 μM) action on the expression of these proangiogenic factors in triple negative breast cancer cells MDA-MB-231, as well as the effect of their conditioned medium (CM) on endothelial cells. Exposure to pesticides increased HIF-1α and VEGF protein expression in an AhR-dependent manner. In addition, HCB and CPF boosted NOS-2 and COX-2 content and VEGF secretion in MDA-MB-231 cells. The treatment of endothelial cells with CM from tumor cells exposed to pesticides increased cell proliferation, migration, and tubule formation, enhancing both tubule length and branching points. Of note, these effects were VEGF-dependent, as they were blocked in the presence of a VEGF receptor-2 (VEGFR-2) inhibitor. In sum, our results highlight the harmful impact of HCB and CPF in modulating the interaction between breast cancer and endothelial cells and promoting angiogenesis.

Circular RNA MKLN1 promotes epithelial-mesenchymal transition in pulmonary fibrosis by regulating the miR-26a/b-5p/CDK8 axis in human alveolar epithelial cells and mice models

Pulmonary fibrosis involves destruction of the lung parenchyma and extracellular matrix deposition. Effective treatments for pulmonary fibrosis are lacking and its pathogenesis is still unclear. Studies have found that epithelial-mesenchymal transition (EMT) of alveolar epithelial cells (AECs) plays an important role in progression of pulmonary fibrosis. Thus, an in-depth exploration of its mechanism might identify new therapeutic targets. In this study, we revealed that a novel circular RNA, MKLN1 (circMKLN1), was significantly elevated in two pulmonary fibrosis models (intraperitoneally with PQ, 50 mg/kg for 7 days, and intratracheally with BLM, 5 mg/kg for 28 days). Additionally, circMKLN1 was positively correlated with the severity of pulmonary fibrosis. Inhibition of circMKLN1 expression significantly reduced collagen deposition and inhibited EMT in AECs. EMT was aggravated after circMKLN1 overexpression in AECs. MiR-26a-5p/miR-26b-5p (miR-26a/b), the targets of circMKLN1, were confirmed by luciferase reporter assays. CircMKLN1 inhibition elevated miR-26a/b expression. Significantly decreased expression of CDK8 (one of the miR-26a/b targets) was observed after inhibition of circMKLN1. EMT was exacerbated again, and CDK8 expression was significantly increased after circMKLN1 inhibition and cotransfection of miR-26a/b inhibitors in AECs. Our research indicated that circMKLN1 promoted CDK8 expression through sponge adsorption of miR-26a/b, which regulates EMT and pulmonary fibrosis. This study provides a theoretical basis for finding new targets or biomarkers in pulmonary fibrosis.

E3 ubiquitin ligase NEDD4L inhibits epithelial-mesenchymal transition by suppressing the β-catenin/HIF-1α positive feedback loop in chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyp (CRSwNP) is a refractory inflammatory disease with epithelial-mesenchymal transition (EMT) as one of the key features. Since ubiquitin modification has been shown to regulate the EMT process in other diseases, targeting ubiquitin ligases may be a potential strategy for the treatment of CRSwNP. In this study we investigated whether certain E3 ubiquitin ligases could regulate the EMT process in CRSwNP, and whether these regulations could be the potential drug targets as well as the underlying mechanisms. After screening the potential drug target by bioinformatic analyses, the expression levels of three potential E3 ubiquitin ligases were compared among the control, eosinophilic nasal polyp (ENP) and non-eosinophilic nasal polyp (NENP) group in clinical samples, and the significant decrement of the expression level of NEDD4L was found. Then, IP-MS, bioinformatics and immunohistochemistry studies suggested that low NEDD4L expression may be associated with the EMT process. In human nasal epithelial cells (hNECs) and human nasal epithelial cell line RPMI 2650, knockdown of NEDD4L promoted EMT, while upregulating NEDD4L reversed this effect, suggesting that NEDD4L inhibited EMT in nasal epithelial cells. IP-MS and Co-IP studies revealed that NEDD4L mediated the degradation of DDR1. We demonstrated that NEDD4L inhibited the β-catenin/HIF-1α positive feedback loop either directly (degrading β-catenin and HIF-1α) or indirectly (mediating DDR1 degradation). These results were confirmed in a murine NP model in vivo. This study for the first time reveals the regulatory role of ubiquitin in the EMT process of nasal epithelial cells, and identifies a novel drug target NEDD4L, which has promising efficacy against both ENP and NENP by suppressing β-catenin/HIF-1α positive feedback loop.

Bisphenol A exposure stimulates prostatic fibrosis via exosome-triggered epithelium changes

Fibrosis is the pathological basis for the clinical progression of benign prostatic hyperplasia (BPH). Prostatic fibrosis is an important risk factor in patients with BPH who experience lower urinary tract symptoms. Bisphenol A (BPA) is an environmental endocrine disruptor (EED) that causes prostate defects. The effects of BPA on the prostate were investigated in this study using mouse and human prostate cell models. BPA-induced mouse prostatic fibrosis is characterized by collagen deposition and an increase in hydroxyproline concentration. Furthermore, BPA-exposed prostatic stromal fibroblasts exosomes promote the epithelial-mesenchymal transition of epithelial cells. High-throughput RNA sequencing and functional enrichment analyses show that substantially altered mRNAs, lncRNAs and circRNAs play roles in cellular interactions and the hypoxia-inducible factor-1 signaling pathway. The results showed that exosomes participated in the pro-fibrogenic effects of BPA on the prostate by mediating communication between stromal and epithelial cells and triggering epithelial changes.

27-Hydroxycholesterol activates the GSK-3β/β-catenin signaling pathway resulting in intestinal fibrosis by inducing oxidative stress: effect of dietary interventions

OBJECTIVE

Intestinal fibrosis, a common and serious complication of inflammatory bowel disease (IBD), results from chronic inflammation. A high-cholesterol diet may be a risk factor for IBD and 27-hydroxylcholesterol (27HC) is the main human cholesterol metabolite. This study investigated whether 27HC can induce intestinal fibrosis.

METHODS

The effects of cholesterol and 27HC on intestinal fibrosis were assessed in zebrafish and human intestinal epithelial Caco-2 cells.

RESULTS

Cholesterol and 27HC induced intestinal inflammation and collagen deposition, inhibited E-cadherin (E-ca) expression in the intestinal epithelium, and promoted nuclear translocation of β-catenin in zebrafish. Cholesterol and 27HC up-regulated expression of COL-1, α-SMA, CTGF, TIMP1, N-cadherin, vimentin, glycogen synthesis kinase-3β (GSK-3β) and β-catenin, but inhibited E-ca, in Caco-2 cells. The expression of these proteins was inhibited by CYP27A1 knockdown and β-catenin knockdown. 27HC-induced nuclear translocation of β-catenin occurs in Caco-2 cells. p38, ERK, and AKT activate β-catenin and thereby participate in 27HC-induced epithelia-mesenchymal transition (EMT) and fibrosis. 27HC-increased oxidative stress and the fibrosis and EMT markers, the nuclear translocation of β-catenin, and the up-regulation of p-cell kinase proteins promoted by 27HC were inhibited by N-acetyl-L-cysteine (NAC). Folic acid (FA), resveratrol (RES), and NAC all ameliorated the 27HC-induced effects in Caco-2 cells and zebrafish.

CONCLUSION

A high-cholesterol diet caused intestinal fibrosis in zebrafish, mediated by a major cholesterol metabolite, 27HC. 27HC increased oxidative stress and activated p38, ERK, AKT, and β-catenin, leading to EMT of epithelial cells and intestinal fibrosis. FA and RES both ameliorated intestinal fibrosis by restraining 27HC-induced β-catenin activation.

Glycolysis Reprogramming in Idiopathic Pulmonary Fibrosis: Unveiling the Mystery of Lactate in the Lung

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease characterized by excessive deposition of fibrotic connective tissue in the lungs. Emerging evidence suggests that metabolic alterations, particularly glycolysis reprogramming, play a crucial role in the pathogenesis of IPF. Lactate, once considered a metabolic waste product, is now recognized as a signaling molecule involved in various cellular processes. In the context of IPF, lactate has been shown to promote fibroblast activation, myofibroblast differentiation, and extracellular matrix remodeling. Furthermore, lactate can modulate immune responses and contribute to the pro-inflammatory microenvironment observed in IPF. In addition, lactate has been implicated in the crosstalk between different cell types involved in IPF; it can influence cell-cell communication, cytokine production, and the activation of profibrotic signaling pathways. This review aims to summarize the current research progress on the role of glycolytic reprogramming and lactate in IPF and its potential implications to clarify the role of lactate in IPF and to provide a reference and direction for future research. In conclusion, elucidating the intricate interplay between lactate metabolism and fibrotic processes may lead to the development of innovative therapeutic strategies for IPF.

Effect of WISP1 on paraquat-induced EMT

BACKGROUND

Paraquat (PQ) can induce pulmonary fibrosis (PF) by modulating epithelial-mesenchymal transition (EMT) of alveolar epithelial cells, but the molecular mechanism is unknown. In this paper, the role of Wnt-inducible signaling protein-1 (WISP1) in PQ-induced EMT was inspected.

METHODS

The morphology, apoptosis, and mortality of A549 cells were observed through a microscope. The mRNA and protein levels of WISP1, E-cadherin, and Vimentin were confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot.

RESULTS

With the increase of PQ concentration, the morphology of A549 cells was apparently changed, cell apoptosis and mortality were enhanced. Besides, the E-cadherin abundance was reduced (p < 0.01), however, WISP1 and Vimentin contents were boosted after PQ treatment (p < 0.01). With the increase of PQ treatment time, the epithelial index of cells first increased and then decreased. The expression of WISP1 gene increased significantly with the increase of PQ treatment time (p < 0.01). Silence of WISP1 abolished the effect of PQ treatment on E-cadherin and Vimentin levels (p < 0.01). Downregulation of WISP1 curbed morphology change and PQ-induced EMT in A549 cells.

CONCLUSION

Knockdown of WISP1 inhibited PQ-induced EMT in A549 cells. This conclusion might provide a new therapeutic target for PQ poisoning treatment.

A novel 2D g-C3N4 material applied for Paraquat adsorbing and detoxifying in vitro and in vivo

In the environmental safety area, the widespread use of the herbicide Paraquat (PQ) poses a great threat to hydrobionts and mammals. Due to the lack of specific antidote, it may lead to irreversible pulmonary fibrosis with a mortality rate of 60%. Therefore, it is necessary to develop an effective and specific PQ antidote. The g-C3N4 (HPCN) with excellent surface physicochemical properties was prepared by a two-step calcination method using urea and dicyandiamide as raw materials, showing a significant photocatalyst against environmental PQ pollution. The SEM results showed that HPCN possesses a porous layered structure. X-ray diffraction and infrared spectroscopy indicated that the conjugated aromatic rings were orderly stacked, forming a 2D layered structure of g-C3N4. The HPCN had a larger specific surface area (56.84 m2 g-1) and pore volume (0.2718 cm3 g-1), which enhanced its adsorption capacity and photocatalytic activity. HPCN exhibited an effective adsorption rate of 38.25% for PQ in water under light. Compared with the PQ group (54.8%), the cell viability of the HPCN group (91.4%) significantly increased by 36.6%, and the SEM observation revealed the restoration of normal cell morphology. The HPCN effectively reduced PQ content in zebrafish and mice in vivo, resulting in an approximately 70% increase in survival rate. The UV-Vis results indicated that the adsorption rate of HPCN for PQ in zebrafish was 43.5%. The enhanced catalytic performance of HPCN provides a promising solution for the detoxification of PQ and of other environmental pollutants.

Astragaloside IV protects against lung injury and pulmonary fibrosis in COPD by targeting GTP-GDP domain of RAS and downregulating the RAS/RAF/FoxO signaling pathway

BACKGROUND

Pulmonary fibrosis is a chronic progressive interstitial lung disease characterized by the replacement of lung parenchyma with fibrous scar tissue, usually as the final stage of lung injury like COPD. Astragaloside IV (AST), a bioactive compound found in the Astragalus membranaceus (Fisch.) used in traditional Chinese medicine, has been shown to improve pulmonary function and exhibit anti-pulmonary fibrosis effects. However, the exact molecular mechanisms through which it combats pulmonary fibrosis, especially in COPD, remain unclear.

PURPOSE

This study aimed to identify the potential therapeutic target and molecular mechanisms for AST in improving lung injury especially treating COPD type pulmonary fibrosis both in vivo and in vitro.

METHODS

Multi lung injury models were established in mice using lipopolysaccharide (LPS), cigarette smoke (CS), or LPS plus CS to simulate the processes of pulmonary fibrosis in COPD. The effect of AST on lung function protection was evaluated, and proteomic and metabolomic analysis were applied to identify the signaling pathway affected by AST and to find potential targets of AST. The interaction between AST and wild-type and mutant RAS proteins was studied. The RAS/RAF/FoxO signaling pathway was stimulated in BEAS-2B cells and in mice lung tissues by LPS plus CS to investigate the anti-pulmonary fibrosis mechanism of AST analyzed by western blotting. The regulatory effects of AST on the RAS/RAF/FoxO pathway dependent on RAS were further confirmed using RAS siRNA.

RESULTS

RAS was predicted and identified as the target protein of AST in anti-pulmonary fibrosis in COPD and improving lung function. The administration of AST was observed to impede the conversion of fibroblasts into myofibroblasts, reduce the manifestation of inflammatory factors and extracellular matrix, and hinder the activation of epithelial mesenchymal transition (EMT). Furthermore, AST significantly suppressed the RAS/RAF/FoxO signaling pathway in both in vitro and in vivo settings.

CONCLUSION

AST exhibited lung function protection and anti-pulmonary fibrosis effect by inhibiting the GTP-GDP domain of RAS, which downregulated the RAS/RAF/FoxO signaling pathway. This study revealed AST as a natural candidate molecule for the protection of pulmonary fibrosis in COPD.

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

AIMS

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

MAIN METHODS

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

KEY FINDINGS

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

SIGNIFICANCE

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

Predicting acute paraquat toxicity using physiologically based kinetic modelling incorporating in vitro active renal excretion via the OCT2 transporter

Including active renal excretion in physiologically based kinetic (PBK) models can improve their use in quantitative in vitro- in vivo extrapolation (QIVIVE) as a new approach methodology (NAM) for predicting the acute toxicity of organic cation transporter 2 (OCT2) substrates like paraquat (PQ). To realise this NAM, kinetic parameters Vmax and Km for in vitro OCT2 transport of PQ were obtained from the literature. Appropriate scaling factors were applied to translate the in vitro Vmax to an in vivo Vmax. in vitro cytotoxicity data were defined in the rat RLE-6TN and L2 cell lines and the human A549 cell line. The developed PQ PBK model was used to apply reverse dosimetry for QIVIVE translating the in vitro cytotoxicity concentration-response curves to predicted in vivo toxicity dose-response curves after which the lower and upper bound benchmark dose (BMD) for 50% lethality (BMDL50 and BMDU50) were derived by applying BMD analysis. Comparing the predictions to the in vivo reported LD50 values resulted in a conservative prediction for rat and a comparable prediction for human showing proof of principle on the inclusion of active renal excretion and prediction of PQ acute toxicity for the developed NAM.

Overexpression of KLF4 Suppresses Pulmonary Fibrosis through the HIF-1α/Endoplasmic Reticulum Stress Signaling Pathway

The hypoxia-inducible factor-1α/endoplasmic reticulum stress signaling pathway (HIF-1α/ERS) has a crucial role in the pathogenetic mechanism of pulmonary fibrosis (PF). However, the upstream regulatory mediators of this pathway remain unclear. In the present study, by conducting bioinformatics analysis, we found that Krüppel-like factor 4 (KLF4) expression was decreased in the lung tissues of patients with idiopathic pulmonary fibrosis (IPF) as compared to that in patients with non-IPF. Furthermore, KLF4 expression was significantly reduced (p = 0.0331) in bleomycin-induced fibrotic HFL-1 cells. Moreover, in mice with bleomycin-induced PF, the degree of fibrosis was significantly reduced in mice overexpressing KLF4 as compared to that in wild-type mice. In mice and HFL-1 cells, KLF4 overexpression significantly reduced bleomycin-induced protein expression of HIF-1α (p = 0.0027) and ERS markers, particularly p-IRE1α (p = 0.0255) and ATF6 (p = 0.0002). By using the JASPAR database, we predicted that KLF4 has five binding sites for the HIF-1α promoter. The results of in vitro and in vivo studies suggest that KLF4 may inhibit PF through the HIF-1α/ERS pathway. This finding could guide the development of future therapies for PF and facilitate the identification of appropriate biomarkers for routine clinical diagnosis of PF.

IDENTIFICATION AND CLINICAL VALIDATION OF HYPOXIA-INDUCIBLE FACTOR 1α PROTEIN AS THE POTENTIAL BIOMARKER IN PATIENTS WITH SEPSIS

ABSTRACT

Objective: Sepsis is a complex disease characterized by an inflammatory response and tissue hypoxia. Hypoxia-inducible factor 1α (HIF-1α) expression level is regulated by hypoxia and inflammation. This study aimed to explore the correlation between HIF-1α expression level and sepsis by bioinformatics analysis and clinical investigation. Methods: Bioinformatics tools were used to identify differentially expressed genes between sepsis and nonsepsis groups using the Gene Expression Omnibus data set. A clinical investigation was carried out to validate HIF-1α protein level in 54 nonseptic patients and 173 septic patients who were followed up for 28 days. Results: Bioinformatics analysis revealed that HIF-1α messenger RNA level was significantly different between septic and nonseptic patients ( P < 0.05). Consistent with the study hypothesis, higher HIF-1α levels in plasma were found in septic patients compared with those in nonseptic patients. The diagnostic accuracy for sepsis, as quantified by the area under the curve, was 0.926 (0.885-0.968) for HIF-1α expression level combined with oxygen saturation to fraction of inspired oxygen (SpO 2 /FiO 2 ), white blood cell, and blood urea nitrogen. The HIF-1α expression level was also significantly correlated with the severity of the disease. The results of the restricted cubic splines model indicated a U-shaped relationship between HIF-1α expression level and intensive care unit (ICU) mortality. Univariate and multivariate linear regression analyses indicated that septic patients with the elevated HIF-1α expression levels had shorter length of ICU stay versus those with the lower HIF-1α expression levels. Conclusion: Hypoxia-inducible factor 1α expression level can be used for diagnosing disease, assessing severity, and predicting length of ICU stay in septic patients.

Understanding and targeting resistance mechanisms in cancer

Resistance to cancer therapies has been a commonly observed phenomenon in clinical practice, which is one of the major causes of treatment failure and poor patient survival. The reduced responsiveness of cancer cells is a multifaceted phenomenon that can arise from genetic, epigenetic, and microenvironmental factors. Various mechanisms have been discovered and extensively studied, including drug inactivation, reduced intracellular drug accumulation by reduced uptake or increased efflux, drug target alteration, activation of compensatory pathways for cell survival, regulation of DNA repair and cell death, tumor plasticity, and the regulation from tumor microenvironments (TMEs). To overcome cancer resistance, a variety of strategies have been proposed, which are designed to enhance the effectiveness of cancer treatment or reduce drug resistance. These include identifying biomarkers that can predict drug response and resistance, identifying new targets, developing new targeted drugs, combination therapies targeting multiple signaling pathways, and modulating the TME. The present article focuses on the different mechanisms of drug resistance in cancer and the corresponding tackling approaches with recent updates. Perspectives on polytherapy targeting multiple resistance mechanisms, novel nanoparticle delivery systems, and advanced drug design tools for overcoming resistance are also reviewed.

The Role of Histone Deacetylases in Acute Lung Injury-Friend or Foe

Acute lung injury (ALI), caused by intrapulmonary or extrapulmonary factors such as pneumonia, shock, and sepsis, eventually disrupts the alveolar-capillary barrier, resulting in diffuse pulmonary oedema and microatasis, manifested by refractory hypoxemia, and respiratory distress. Not only is ALI highly lethal, but even if a patient survives, there are also multiple sequelae. Currently, there is no better treatment than supportive care, and we urgently need to find new targets to improve ALI. Histone deacetylases (HDACs) are epigenetically important enzymes that, together with histone acetylases (HATs), regulate the acetylation levels of histones and non-histones. While HDAC inhibitors (HDACis) play a therapeutic role in cancer, inflammatory, and neurodegenerative diseases, there is also a large body of evidence suggesting the potential of HDACs as therapeutic targets in ALI. This review explores the unique mechanisms of HDACs in different cell types of ALI, including macrophages, pulmonary vascular endothelial cells (VECs), alveolar epithelial cells (AECs), and neutrophils.

Role of HIF-1α in pathogenic mechanisms of keloids

BACKGROUDS AND OBJECTIVE

Keloids are defined as overrepairing products that develop after skin lesions. Keloids are characterized by the proliferation of fibroblasts and the overaccumulation of extracellular matrix components (mainly collagen), leading to a locally hypoxic microenvironment. Hence, this article was aimed to review hypoxia in pathogenesis of keloids.

METHODS

We reviewed and summarized the relevant published studies.

RESULTS

Hypoxia results in the accumulation of hypoxia-inducible factor 1α (HIF-1α) in keloids, contributing to overactivation of the fibrotic signaling pathway, epithelial-mesenchymal transition, and changes in metabolism, eventually leading to aggravated fibrosis, infiltrative growth, and radiotherapy resistance.

CONCLUSION

It is, therefore, essential to understand the role of HIF-1α in the pathogenic mechanisms of keloids in order to develop new therapeutic approaches.

HIF-1α promotes paraquat induced acute lung injury and implicates a role NF-κB and Rac2 activity

Paraquat (PQ) is a bipyridine herbicide and oral exposure is the main way of PQ exposure with a very high mortality. At present, it is believed that large number of oxygen free radicals are generated and cause lipid peroxidation of tissue and organ cell membranes after PQ is absorbed. PQ exposure could cause multiple organ dysfunction, among which acute lung injury is the most common and most serious. However, its specific mechanism is still unclear. In this study, the C57BL/6J mouse (alveolar epithelial cell-specific knockout HIF-1α) model of acute lung injury (40 mg/kg PQ) at several time pointes and a model of acute type II alveolar epithelial cell (A549, 800 μM PQ) injury constructed. The oxidative stress (ROS, MDA) and inflammatory response (IL-1β, IL-6, TNF-α) were significantly inhibited in the alveolar epithelial cell-specific knockout of HIF-1α mice and siRNA technology to inhibit HIF-1α in alveolar epithelial cells. Further proteomic analysis showed that the expression of Rac2 protein, which is closely related to oxidative stress, was significantly increased after PQ exposure. And the inhibition of Rac2 expression in vitro significantly alleviated PQ-induced oxidative stress and inflammatory response. The expression of Rac2 protein was regulated by HIF-1α. The above suggests that HIF-1α may promote oxidative stress and inflammatory response in alveolar epithelial cells by regulating the expression of Rac2, and then participate in the promotion of PQ exposure-induced acute lung injury.

Inositol Alleviates Pulmonary Fibrosis by Promoting Autophagy via Inhibiting the HIF-1α-SLUG Axis in Acute Respiratory Distress Syndrome

The effective remission of acute respiratory distress syndrome- (ARDS-) caused pulmonary fibrosis determines the recovery of lung function. Inositol can relieve lung injuries induced by ARDS. However, the mechanism of myo-inositol in the development of ARDS is unclear, which limits its use in the clinic. We explored the role and mechanism of myo-inositol in the development of ARDS by using an in vitro lipopolysaccharide- (LPS-) established alveolar epithelial cell inflammation model and an in vivo ARDS mouse model. Our results showed that inositol can alleviate the progression of pulmonary fibrosis. More significantly, we found that inositol can induce autophagy to inhibit the progression pulmonary fibrosis caused by ARDS. In order to explore the core regulators of ARDS affected by inositol, mRNA-seq sequencing was performed. Those results showed that transcription factor HIF-1α can regulate the expression of SLUG, which in turn can regulate the key gene E-Cadherin involved in cell epithelial-mesenchymal transition (EMT) as well as N-cadherin expression, and both were regulated by inositol. Our results suggest that inositol activates autophagy to inhibit EMT progression induced by the HIF-1α/SLUG signaling pathway in ARDS, and thereby alleviates pulmonary fibrosis.

Hypoxia-Induced HIF-1α Expression Promotes Neurogenic Bladder Fibrosis via EMT and Pyroptosis

BACKGROUND

Neurogenic bladder (NB) patients exhibit varying degrees of bladder fibrosis, and the thickening and hardening of the bladder wall induced by fibrosis will further affect bladder function and cause renal failure. Our study aimed to investigate the mechanism of bladder fibrosis caused by a spinal cord injury (SCI).

METHODS

NB rat models were created by cutting the bilateral lumbar 6 (L6) and sacral 1 (S1) spinal nerves. RNA-seq, Western blotting, immunofluorescence, cell viability and ELISA were performed to assess the inflammation and fibrosis levels.

RESULTS

The rats showed bladder dysfunction, upper urinary tract damage and bladder fibrosis after SCI. RNA-seq results indicated that hypoxia, EMT and pyroptosis might be involved in bladder fibrosis induced by SCI. Subsequent Western blot, ELISA and cell viability assays and immunofluorescence of bladder tissue confirmed the RNA-seq findings. Hypoxic exposure increased the expression of HIF-1α and induced EMT and pyroptosis in bladder epithelial cells. Furthermore, HIF-1α knockdown rescued hypoxia-induced pyroptosis, EMT and fibrosis.

CONCLUSION

EMT and pyroptosis were involved in the development of SCI-induced bladder fibrosis via the HIF-1α pathway. Inhibition of the HIF-1α pathway may serve as a potential target to alleviate bladder fibrosis caused by SCI.

Value of biomarkers in epithelial-mesenchymal transition models of liver cancer under different interventions: a meta-analysis

Aim: A meta-analysis was conducted to evaluate the effectiveness of crucial biomarkers in HepG2 cells during epithelial-mesenchymal transformation induced by multiple interventions. Methods: PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wan Fang Data and VIP databases were systematically searched from inception to 14 June 2020, by two independent reviewers. Results: A total of 58 studies were included in the meta-analysis. E-cadherin, N-cadherin and vimentin performed well under medicinal interventions. E-cadherin worked well under genetic interventions. E-cadherin and N-cadherin also performed significantly well under tumor microenvironment interventions. Under ncRNA interventions, the expression of E-cadherin significantly changed. Conclusion: Different sets of biomarkers should be selected under various interventions based on their performance.

Paraquat is an agonist of STIM1 and increases intracellular calcium levels

Paraquat (PQ) is an efficient herbicide but leads to high mortality with no antidote in mammals. PQ produces reactive oxygen species (ROS), leading to epithelial-mesenchymal transition (EMT) for pulmonary fibrosis in type II alveolar (AT II) cells. Intriguingly, strategies reducing ROS exhibit limited therapeutic effects, indicating other targets existing for PQ toxicity. Herein we report that PQ is also an agonist for STIM1 that increases intracellular calcium levels. Particularly, PQ promotes STIM1 puncta formation and association with TRPC1 or ORAI for extracellular calcium entry and thus intracellular calcium influx. Further studies reveal the importance of P584&Y586 residues in STIM1 for PQ association that facilitates STIM1 binding to TRPC1. Consequently, the STIM1-TRPC1 route facilitates PQ-induced EMT for pulmonary fibrosis as well as cell death. Our results demonstrate that PQ is an agonist of STIM1 that induces extracellular calcium entry, increases intracellular calcium levels, and thus promotes EMT in AT II cells.

Melatonin through blockade of Hif-1α signaling mediates the anti-fibrosis under hypoxia in canine Sertoli cells

The hypoxic microenvironment of cryptorchidism is an important factor in the impairment and fibrosis of Sertoli cells which result in blood-testis barrier (BTB) destruction and spermatogenesis loss. Recent studies have shown that melatonin, a well-known pineal hormone exerts beneficial effects against pathological fibrosis in a various of organs. However, it is still unknown whether melatonin can regulate hypoxia-induced fibrosis of Sertoli cells. In this study we evaluate melatonin levels, and its synthesizing enzymes, AANAT and HIOMT expression patterns in canine cryptorchidism and contralateral normal testis. Results show abdominal testes presented low melatonin levels and AANAT and HIOMT expression compared with testes located in the scrotum. Moreover, we established a hypoxia-induced fibrosis model in canine Sertoli cells induced by cobalt chloride (CoCl₂) and found that melatonin inhibited the EMT markers expression and ECM production as well as Hif-1α expression of Sertoli cells in a dose-dependent manner. Furthermore, use of Lificiguat (synonyms YC-1, Hif-1α inhibitor) to interfere with the Hif-1α pathway showed a similar effect with melatonin suppression of the fibrosis in Sertoli cells. The results indicate that melatonin supplementation can alleviate the fibrosis process of Sertoli cells caused by hypoxia, which is associated with regulating the inhibition of Hif-1α signaling.

Regulating the Expression of HIF-1α or lncRNA: Potential Directions for Cancer Therapy

Previous studies have shown that tumors under a hypoxic environment can induce an important hypoxia-responsive element, hypoxia-induced factor-1α (HIF-1α), which can increase tumor migration, invasion, and metastatic ability by promoting epithelial-to-mesenchymal transition (EMT) in tumor cells. Currently, with the deeper knowledge of long noncoding RNAs (lncRNAs), more and more functions of lncRNAs have been discovered. HIF-1α can regulate hypoxia-responsive lncRNAs under hypoxic conditions, and changes in the expression level of lncRNAs can regulate the production of EMT transcription factors and signaling pathway transduction, thus promoting EMT progress. In conclusion, this review summarizes the regulation of the EMT process by HIF-1α and lncRNAs and discusses their relationship with tumorigenesis. Since HIF-1α plays an important role in tumor progression, we also summarize the current drugs that inhibit tumor progression by modulating HIF-1α.

Contribution of Adiponectin/Carnitine Palmityl Transferase 1A-Mediated Fatty Acid Metabolism during the Development of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that leads rapidly to death. The present study is aimed at discovering the in-depth pathogenesis of IPF, exploring the role of adiponectin/carnitine palmityl transferase 1A- (APN/CPT1A-) mediated fatty acid metabolism during the development of IPF, and excavating its potential mechanism. Here, THP-1 cells were differentiated into M0 macrophages, followed by polarization to M1 macrophages upon hypoxia. Subsequently, lung fibroblast HFL-1 cells were stimulated by M1 macrophages to simulate hypoxia-related IPF condition in vitro. It was discovered that the stimulation of M1 macrophages promoted fibroblast proliferation and fibrosis formation in vitro, accompanied with a disorder of the APN/CPT1A pathway, an overproduction of lipid peroxides, and a low level of autophagy in HFL-1 cells. Thereafter, APN treatment or CPT1A overexpression greatly suppressed above lipid peroxide accumulation, fibroblast proliferation, and fibrosis but activated autophagy in vitro. Furthermore, an in vivo IPF rat model was established by injection of bleomycin (BLM). Consistently, CPT1A overexpression exerted a protective role against pulmonary fibrosis in vivo; however, the antifibrosis property of CPT1A was partly abolished by 3-methyladenine (an autophagy inhibitor). In summary, APN/CPT1A-mediated fatty acid metabolism exerted its protective role in IPF partly through activating autophagy, shedding a new prospective for the treatment of IPF.

Panax Notoginseng Saponins Regulate Transforming Growth Factor-β1 through MAPK and Snail/TWIST1 Signaling Pathway to Inhibit Epithelial-Mesenchymal Transition of Pulmonary Fibrosis in A549 Cells

Panaxnotoginseng saponins (PNS) is one of the active components of traditional Chinese medicine Panax notoginseng which has the function of reducing oxygen consumption, expansion of the cerebrovascular system, and is antithrombotic. PNS also plays a role in the treatment of pulmonary fibrosis. In this study, we found that PNS suppresses fibroblast-like changes in A549 cells through epithelial-mesenchymal transition (EMT). PNS promoted E-cadherin (E-cad) in epithelial cells and decreased Fibronectin (FN) and Vimentin (Vim) expression in myofibroblasts in a dose-dependent manner. Further mechanism studies have shown that PNS inhibits the EMT process by regulating p38, JNK, and Erk signaling factors in the MAPK signaling pathway and then blocking Snail and TWIST1 transcription factors from entering the nucleus. This indicates that PNS can regulate epithelial-mesenchymal transition through MAPK and the Snail/TWIST1 signaling pathway, thereby exerting its antipulmonary fibrosis effect.

Histone deacetylase 3 promotes alveolar epithelial-mesenchymal transition and fibroblast migration under hypoxic conditions

Epithelial–mesenchymal transition (EMT), a process by which epithelial cells undergo a phenotypic conversion that leads to myofibroblast formation, plays a crucial role in the progression of idiopathic pulmonary fibrosis (IPF). Recently, it was revealed that hypoxia promotes alveolar EMT and that histone deacetylases (HDACs) are abnormally overexpressed in the lung tissues of IPF patients. In this study, we showed that HDAC3 regulated alveolar EMT markers via the AKT pathway during hypoxia and that inhibition of HDAC3 expression by small interfering RNA (siRNA) decreased the migration ability and invasiveness of diseased human lung fibroblasts. Furthermore, we found that HDAC3 enhanced the migratory and invasive properties of fibroblasts by positively affecting the EMT process, which in turn was affected by the increased and decreased levels of microRNA (miR)-224 and Forkhead Box A1 (FOXA1), respectively. Lastly, we found this mechanism to be valid in an in vivo system; HDAC3 siRNA administration inhibited bleomycin-induced pulmonary fibrosis in mice. Thus, it is reasonable to suggest that HDAC3 may accelerate pulmonary fibrosis progression under hypoxic conditions by enhancing EMT in alveolar cells through the regulation of miR-224 and FOXA1. This entire process, we believe, offers a novel therapeutic approach for pulmonary fibrosis.

Inhibiting an enzyme that boosts the invasiveness of fibrosis-related cells could prove to be a novel therapeutic strategy for treating idiopathic lung fibrosis. Lung fibrosis progresses via the transition of epithelial cells into myofibroblasts, which are migratory invasive cell types that secrete collagen and deposit excessive extracellular material. Low oxygen conditions (hypoxia) accelerate this transition process. Scientists recently identified a group of histone deacetylases (HDACs) that are significantly overexpressed in the lung tissues of patients with fibrosis. In experiments on mice and human cell lines, Jeong-Woong Park and Se-Hee Kim at Gachon University Gil Medical Center, Incheon, South Korea, and co-workers demonstrated that under hypoxic conditions, HDAC3 increases the cellular transition to myofibroblasts by regulating the expression of a key microRNA and its target gene. Inhibiting HDAC3 suppresses the migration and invasiveness of lung myofibroblasts.

Hypoxia-inducible factors: master regulators of hypoxic tumor immune escape

Hypoxia, a common feature of the tumor microenvironment in various types of cancers, weakens cytotoxic T cell function and causes recruitment of regulatory T cells, thereby reducing tumoral immunogenicity. Studies have demonstrated that hypoxia and hypoxia-inducible factors (HIFs) 1 and 2 alpha (HIF1A and HIF2A) are involved in tumor immune escape. Under hypoxia, activation of HIF1A induces a series of signaling events, including through programmed death receptor-1/programmed death ligand-1. Moreover, hypoxia triggers shedding of complex class I chain-associated molecules through nitric oxide signaling impairment to disrupt immune surveillance by natural killer cells. The HIF-1-galactose-3-O-sulfotransferase 1-sulfatide axis enhances tumor immune escape via increased tumor cell-platelet binding. HIF2A upregulates stem cell factor expression to recruit tumor-infiltrating mast cells and increase levels of cytokines interleukin-10 and transforming growth factor-β, resulting in an immunosuppressive tumor microenvironment. Additionally, HIF1A upregulates expression of tumor-associated long noncoding RNAs and suppresses immune cell function, enabling tumor immune escape. Overall, elucidating the underlying mechanisms by which HIFs promote evasion of tumor immune surveillance will allow for targeting HIF in tumor treatment. This review discusses the current knowledge of how hypoxia and HIFs facilitate tumor immune escape, with evidence to date implicating HIF1A as a molecular target in such immune escape. This review provides further insight into the mechanism of tumor immune escape, and strategies for tumor immunotherapy are suggested.

Inhibition of HIF-1α Attenuates Silica-Induced Pulmonary Fibrosis

Background: Excessive accumulation of extracellular matrix is a key feature of pulmonary fibrosis (PF), and myofibroblasts are the main producers of extracellular matrix. Fibroblasts are the major source of myofibroblasts, but the mechanisms of transdifferentiation are unclear. Methods: In vitro, transforming growth factor-β1 was used to induce NIH-3T3 cell transdifferentiation. DMOG was used to increase hypoxia-inducible factor-1α subunit (HIF-1α) expression. KC7F2 and siRNA decreased HIF-1α expression. In vivo, silica particles were used to induce PF in C57BL/6N mice, and KC7F2 was used to reduce HIF-1α expression in C57BL/6N mice. Western blot was used to detect the expression of collagen type 1 alpha 1(COL1A1), α-smooth muscle actin (α-SMA), SMAD family member (SAMD) 3, Phospho-SMAD3 (PSMAD3), and HIF-1α. PCR was used to detect the expression of COL1A1, α-SMA, and HIF-1α. Immunohistochemistry was used to detect the expression of COL1A1 and HIF-1α. Results: In vitro, compared to the control group, COL1A1, α-SMA, PSMAD3, and HIF-1α expression were elevated in the DMOG group, and COL1A1, α-SMA, PSMAD3, and HIF-1α expression were decreased in the KC7F2 group and siRNA group. Compared to the DMOG group, COL1A1, α-SMA, and PSMAD3 expression were decreased in the DMOG + SIS3 group. In vivo, compared to the saline group, COL1A1, α-SMA, PSMAD3, and HIF-1α expression were increased in the pulmonary tissue of C57BL/6N mice in the silica group. Compared to the silica group, COL1A1, α-SMA, PSMAD3, and HIF-1α expression and the degree of PF were decreased in the silica + KC7F2 group. Conclusion: Inhibition of HIF-1α reduced α-SMA, decreased COL1A1 expression, and attenuated the degree of PF in C57BL/6N mice. Therefore, HIF-1α may be a new target for the treatment of silica-induced PF.

Wnt-induced secreted proteins-1 play an important role in paraquat-induced pulmonary fibrosis

Background

The objective of this article is to observe the expression of Wnt-induced secreted proteins-1 (WISP1) in paraquat (PQ)-induced pulmonary fibrosis (PF) to explore the role of WISP1.

Methods

Healthy individuals were included in the control group. Patients who had acute lung injury or PF were included in the PF group. Venous blood samples were collected from the patients on days 1 and 3 following PQ poisoning to detect the expression levels of the WISP1 gene and protein concentration. Any changes in the patients’ blood gas analysis index were reviewed. In addition, chest computed tomography (CT) and x-ray images were observed to evaluate the relationship between WISP1 expression and disease severity.

Results

The expression of the WISP1 gene and the serum WISP1 protein concentration were higher in patients with PQ poisoning combined with PF than in patients without PF (P < 0.01). Serum PQ concentration was positively correlated with WISP1 gene expression (r = 0.621, P < 0.01), and serum WISP1 protein concentration (r = 0.596, P < 0.01) was considered a risk factor [odds ratio (OR) = 4.356, P < 0.05] for PQ-induced PF. Concurrently, the results of the adjusted and non-adjusted OR value for WISP1 gene expression and WISP1 protein concentration on day 1 was, respectively, as follows: OR = 12.797, 95% confidence interval (CI) (2.478–66.076), P = 0.002, OR’ = 11.353, P = 0.005; and OR = 1.545, 95% CI (1.197–1.995), P = 0.001, OR’ = 1.487, P = 0.003. The CT scan of a 20-year-old male with PQ-induced PF (20 ml) was observed, and it showed a typical hyaline-like lesion in the lungs on day 22 after poisoning; on day 33 after poisoning, the lungs showed localised consolidation combined with air bronchography.

Conclusion

The expression of WISP1 was higher in the patients with PQ-induced PF compared with the patients without PF. Accordingly, WISP1 plays an important role in PQ-induced PF.

Endothelial plasticity drives aberrant vascularization and impedes cardiac repair after myocardial infarction

Myocardial infarction (MI) is a leading cause of death worldwide, largely because efficient interventions to restore cardiac function after MI are currently lacking. Here, we characterize vascular aberrancies induced by MI, and propose to target acquired endothelial cell (EC) changes to normalize vessels and promote cardiac repair after MI. Single-cell transcriptome analyses of MI-associated ECs indicates that ECs acquire mesenchymal gene signature that result in phenotypic and functional changes and lead to vessel abnormalities. We identify a PDGF/NF-κB/HIF-1α axis that induces Snail expression and mesenchymal phenotypes in ECs under hypoxia, altogether causing aberrant vascularization. EC-specific knockout of PDGFR-β, pharmacological PDGFR inhibition or nanoparticle-based targeted PDGFR-β siRNA delivery in mice attenuates vascular abnormalities in the infarcted tissue and improves cardiac repair after MI. These findings illustrate a mechanism controlling aberrant neovascularization after ischemia, and suggest that targeting PDGF/Snail-mediated endothelial plasticity may offer opportunities for normalizing vasculature and treating ischemic heart diseases.

Efficacy of Qingfei oral liquid for idiopathic pulmonary fibrosis in rats and related network pharmacology study

To investigate the therapeutic effect and mechanism of Qingfei oral liquid in idiopathic pulmonary fibrosis. Seventy-two male SD rats were divided into control group, model group, pirofenidone group and Qingfei group with 18 animals in each group. The idiopathic pulmonary fibrosis was induced in last three groups by intratracheal injection of bleomycin; pirofenidone group was given oral administration of pirofenidone b.i.d for 21 d, and Qingfei group was given Qingfei oral liquid 3.6 mL/kg q.d for Lung tissues were obtained for HE staining, Masson staining and transforming growth factor (TGF)-β immunohistochemical staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were detected in tissue homogenates. The BATMAN-TCM database was used to retrieve the chemical components and their corresponding targets of Qingfei oral solution by network pharmacology method, and then the component-target-disease network diagram was constructed. Finally, the pathway enrichment analysis was carried out to explore the molecular mechanism of Qingfei oral liquid against idiopathic fibrosis. Histopathology results showed that Qingfei oral liquid had a similar relieving effect on pulmonary fibrosis as the positive drug pirfenidone; TGF-β secretion had a significant reduction in lung tissues of Qingfei group; and Qingfei oral liquid had better regulatory effect on SOD, MDA and GSH than pirfenidone. The results of component-target-disease network and pathway enrichment analysis showed that the related molecular pathways were concentrated in inflammation, extracellular matrix and cytokines. Qingfei oral liquid has a good therapeutic effect on idiopathic pulmonary fibrosis in rats via regulation of inflammation, extracellular matrix and cytokines.

A Preconception Paternal Fish Oil Diet Prevents Toxicant-Driven New Bronchopulmonary Dysplasia in Neonatal Mice

New bronchopulmonary dysplasia is a developmental lung disease associated with placental dysfunction and impaired alveolarization. Risk factors for new BPD include prematurity, delayed postnatal growth, the dysregulation of epithelial-to-mesenchymal transition (EMT), and parental exposure to toxicants. Our group previously reported that a history of paternal toxicant exposure increased the risk of prematurity and low birth weight in offspring. A history of paternal toxicant exposure also increased the offspring's risk of new BPD and disease severity was increased in offspring who additionally received a supplemental formula diet, which has also been linked to poor lung development. Risk factors associated with new BPD are well-defined, but it is unclear whether the disease can be prevented. Herein, we assessed whether a paternal fish oil diet could attenuate the development of new BPD in the offspring of toxicant exposed mice, with and without neonatal formula feeding. We investigated the impact of a paternal fish oil diet preconception because we previously reported that this intervention reduces the risk of TCDD associated placental dysfunction, prematurity, and low birth weight. We found that a paternal fish oil diet significantly reduced the risk of new BPD in neonatal mice with a history of paternal toxicant exposure regardless of neonatal diet. Furthermore, our evidence suggests that the protective effects of a paternal fish oil diet are mediated in part by the modulation of small molecules involved in EMT.

Long Non-Coding RNAs in Oral Submucous Fibrosis: Their Functional Mechanisms and Recent Research Progress

Many studies have shown that most genomes are transcribed into non-coding RNAs (ncRNAs), including microRNAs (miRs) and long non-coding RNAs (lncRNAs), which can affect different cell characteristics. LncRNAs are long heterologous RNAs that regulate gene expression and various signaling pathways during homeostasis and development. Studies have shown that a lncRNA is an important regulatory molecule that can be targeted to change the physiology and function of cells. Expression or dysfunction of lncRNAs is closely related to various genetic, autoimmune, and metabolic diseases. The importance of ncRNAs in oral submucosal fibrosis (OSF) has garnered much attention in recent years. However, most research has focused on miRs. The role of these molecules in OSF is incompletely understood. This review focuses on the emerging role and function of lncRNAs in OSF as novel regulators. Finally, the potential functional role of lncRNAs as biomarkers for OSF diagnosis is also described. LncRNAs are expected to become a new therapeutic target, but more research is needed to understand their biological functions more deeply.

Channeling the Force: Piezo1 Mechanotransduction in Cancer Metastasis

Cancer metastasis is one of the leading causes of death worldwide, motivating research into identifying new methods of preventing cancer metastasis. Recently there has been increasing interest in understanding how cancer cells transduce mechanical forces into biochemical signals, as metastasis is a process that consists of a wide range of physical forces. For instance, the circulatory system through which disseminating cancer cells must transit is an environment characterized by variable fluid shear stress due to blood flow. Cancer cells and other cells can transduce physical stimuli into biochemical responses using the mechanosensitive ion channel Piezo1, which is activated by membrane deformations that occur when cells are exposed to physical forces. When active, Piezo1 opens, allowing for calcium flux into the cell. Calcium, as a ubiquitous second-messenger cation, is associated with many signaling pathways involved in cancer metastasis, such as angiogenesis, cell migration, intravasation, and proliferation. In this review, we discuss the roles of Piezo1 in each stage of cancer metastasis in addition to its roles in immune cell activation and cancer cell death.

A new paradigm for leprosy diagnosis based on host gene expression

Transcriptional profiling is a powerful tool to investigate and detect human diseases. In this study, we used bulk RNA-sequencing (RNA-Seq) to compare the transcriptomes in skin lesions of leprosy patients or controls affected by other dermal conditions such as granuloma annulare, a confounder for paucibacillary leprosy. We identified five genes capable of accurately distinguishing multibacillary and paucibacillary leprosy from other skin conditions. Indoleamine 2,3-dioxygenase 1 (IDO1) expression alone was highly discriminatory, followed by TLR10, BLK, CD38, and SLAMF7, whereas the HS3ST2 and CD40LG mRNA separated multi- and paucibacillary leprosy. Finally, from the main differentially expressed genes (DEG) and enriched pathways, we conclude that paucibacillary disease is characterized by epithelioid transformation and granuloma formation, with an exacerbated cellular immune response, while multibacillary leprosy features epithelial-mesenchymal transition with phagocytic and lipid biogenesis patterns in the skin. These findings will help catalyze the development of better diagnostic tools and potential host-based therapeutic interventions. Finally, our data may help elucidate host-pathogen interplay driving disease clinical manifestations.

MEN1 silencing aggravates tumorigenic potential of AR-independent prostate cancer cells through nuclear translocation and activation of JunD and β-catenin

Background

Recent studies highlighted the increased frequency of AR-low or -negative prostate cancers (PCas) and the importance of AR-independent mechanisms in driving metastatic castration-resistant PCa (mCRPC) development and progression. Several previous studies have highlighted the involvement of the MEN1 gene in PCa. In the current study, we focused on its role specifically in AR-independent PCa cells.

Methods

Cell tumorigenic features were evaluated by proliferation assay, foci formation, colony formation in soft agar, wound healing assay and xenograft experiments in mice. Quantitative RT-PCR, Western blot and immunostaining were performed to determine the expression of different factors in human PCa lines. Different ChIP-qPCR-based assays were carried out to dissect the action of JunD and β-catenin.

Results

We found that MEN1 silencing in AR-independent cell lines, DU145 and PC3, resulted in an increase in anchorage independence and cell migration, accompanied by sustained MYC expression. By searching for factors known to positively regulate MYC expression and play a relevant role in PCa development and progression, we uncovered that MEN1-KD triggered the nuclear translocation of JunD and β-catenin. ChIP and 3C analyses further demonstrated that MEN1-KD led to, on the one hand, augmented binding of JunD to the MYC 5′ enhancer and increased formation of loop structure, and on the other hand, increased binding of β-catenin to the MYC promoter. Moreover, the expression of several molecular markers of EMT, including E-cadherin, BMI1, Twist1 and HIF-1α, was altered in MEN1-KD DU145 and PC3 cells. In addition, analyses using cultured cells and PC3-GFP xenografts in mice demonstrated that JunD and β-catenin are necessary for the altered tumorigenic potential triggered by MEN1 inactivation in AR-independent PCa cells. Finally, we observed a significant negative clinical correlation between MEN1 and CTNNB1 mRNA expression in primary PCa and mCRPC datasets.

Conclusions

Our current work highlights an unrecognized oncosuppressive role for menin specifically in AR-independent PCa cells, through the activation of JunD and β-catenin pathways.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02058-7.

Long noncoding RNA HOTAIR functions as ceRNA to regulate MMP2 in paraquat induced lung epithelial-mesenchymal transition

Paraquat (PQ) poisoning induces epithelial-mesenchymal transition (EMT) in the lungs, resulting in pulmonary fibrosis with a poor prognosis. Although competitive endogenous RNA (ceRNA) networks are known to exert post-transcriptional regulatory effects, the roles of such networks in PQ-induced EMT remain unknown. We explored the potential ceRNA network involved in PQ-induced pulmonary EMT. The male BALB/c mice were injected with 10 mg/kg PQ intraperitoneally and the lungs were harvested at 21^st day. The A549 cells were treated with 60 μmol/L PQ for 6 days. We determined the expression level of epithelia cadherin (E-cadherin) and α-smooth muscle actin (α-SMA) in the lungs and A549 cells after PQ exposure. We also detected the expression level of the long noncoding RNA (lncRNA) HOX transcript antisense intergenic RNA (HOTAIR), microRNA-17-5p (miR-17-5p), and matrix metalloproteinase 2 (MMP2). We used specific siRNA to determine the influence of HOTAIR on MMP2. We also transfected a mimic or inhibitor of miR-17-5p to explore its role. Moreover, we used the luciferase reporter gene assay to confirm the relationship between miR-17-5p and HOTAIR or MMP2. In this study, we found that MMP2 and HOTAIR were upregulated and miR-17-5p was downregulated in PQ-induced EMT. The knockdown of HOTAIR decreased the expression of MMP2, and the upregulation of miR-17-5p suppressed HOTAIR and MMP2. Apparently, the downregulation of miR-17-5p increased the expression of HOTAIR and MMP2. The expression of α-SMA was negatively regulated by miR-17-5p after PQ exposure. In addition, the luciferase reporter gene assay confirmed that HOTAIR and MMP2 had direct binding sites with miR-17-5p. In conclusion, this study showed that the HOTAIR could act as a ceRNA for miR-17-5p to regulate MMP2 expression in PQ-induced pulmonary EMT.

NEDD4L-induced β-catenin ubiquitination suppresses the formation and progression of interstitial pulmonary fibrosis via inhibiting the CTHRC1/HIF-1α axis

Interstitial pulmonary fibrosis (IPF) is a severe progressive lung disease with limited therapeutic options and poor prognosis. Initially, we found the downregulated level of neural precursor cell expressed developmentally down-regulated 4-like protein (NEDD4L) in IPF-related expression microarray dataset, and this study was thus performed to explore the molecular mechanism of NEDD4L in IPF. The expression of NEDD4L was subsequently validated in lung tissues of IPF patients and mouse models. Then, mouse primary lung fibroblasts (LFs) were collected for in vitro functional experiments, with CCK-8, Transwell, and immunofluorescence assays used to examine the viability, migration, and differentiation of LFs. The in vitro findings were further assessed using in vivo mouse models. The expression of NEDD4L was down-regulated in lung tissues of IPF patients and mouse models. Overexpression of NEDD4L restricted the formation and progression of IPF in mice and attenuated the proliferative, invasive and differentiative abilities of LFs. Further, NEDD4L halted LFs activity by enhancing β-catenin ubiquitination and down-regulating the CTHRC1/HIF-1α axis. Also, in vivo experiments then validated that NEDD4L silencing repressed β-catenin ubiquitination and activated the CTHRC1/HIF-1α axis, thereby aggravating IPF in mice. NEDD4L may suppress the formation and progression of IPF through augmenting β-catenin ubiquitination and inhibiting the CTHRC1/HIF-1α axis.

Downregulation of miR‑483‑5p inhibits TGF‑β1‑induced EMT by targeting RhoGDI1 in pulmonary fibrosis

Transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) serves a significant role in pulmonary fibrosis (PF). Increasing evidence indicates that microRNAs (miRNAs or miRs) contribute to PF pathogenesis via EMT regulation. However, the role of miR-483-5p in PF remains unclear. Therefore, the present study investigated the potential effect of miR-483-5p on TGF-β1-induced EMT in PF. It was found that the expression of miR-483-5p was upregulated in both PF tissue and A549 cells treated with TGF-β1, whereas expression of Rho GDP dissociation inhibitor 1 (RhoGDI1) was downregulated. miR-483-5p mimic transfection promoted TGF-β1-induced EMT; by contrast, miR-483-5p inhibitor inhibited TGF-β1-induced EMT. Also, miR-483-5p mimic decreased RhoGDI1 expression, whereas miR-483-5p inhibitor increased RhoGDI1 expression. Furthermore, dual-luciferase reporter gene assay indicated that miR-483-5p directly regulated RhoGDI1. Moreover, RhoGDI1 knockdown eliminated the inhibitory effect of the miR-483-5p inhibitor on TGF-β1-induced EMT via the Rac family small GTPase (Rac)1/PI3K/AKT pathway. In conclusion, these data indicated that miR-483-5p inhibition ameliorated TGF-β1-induced EMT by targeting RhoGDI1 via the Rac1/PI3K/Akt signaling pathway in PF, suggesting a potential role of miR-483-5p in the prevention and treatment of PF.

Fluorofenidone attenuates paraquat‑induced pulmonary fibrosis by regulating the PI3K/Akt/mTOR signaling pathway and autophagy

Paraquat (PQ) is a widely used herbicide that is severely toxic to humans and animals. Pulmonary fibrosis is a disorder that can result from PQ poisoning. Fluorofenidone (AKF‑PD) is a novel small molecule pyridone drug with a widespread and clear anti‑organ fibrosis effect; however, its mechanism of action on PQ poisoning‑induced pulmonary fibrosis is not clear. The purpose of the present study was to investigate the protective effect and underlying mechanism of AKF‑PD on PQ poisoning‑induced pulmonary fibrosis. Human alveolar epithelial cells (HPAEpiC) and Sprague‑Dawley rats were treated with AKF‑PD in the presence or absence of PQ. Hematoxylin‑eosin and Masson staining were used to observe the morphological changes in lung tissue. Cell Counting Kit‑8 and lactate dehydrogenase assays were used to evaluate the viability of HPAEpiC cells. ELISA was used to detect inflammatory factors and the collagen content. Finally, the effects of AKF‑PD on pulmonary fibrosis, as well as the underlying mechanisms, were evaluated via western blotting, reverse transcription‑quantitative PCR and immunofluorescence analysis. AKF‑PD effectively alleviated PQ‑induced pulmonary fibrosis and reduced the expression of oxidative stress and inflammatory factors. Moreover, AKF‑PD treatment effectively inhibited the PI3K/Akt/mTOR signaling pathway and upregulated autophagy. Overall, these findings suggested that AKF‑PD can alleviate PQ‑induced inflammation and pulmonary fibrosis by inhibiting the PI3K/Akt/mTOR signaling pathway and by upregulating autophagy.

Endoplasmic reticulum stress promotes epithelial‑mesenchymal transition via the PERK signaling pathway in paraquat‑induced pulmonary fibrosis

Pulmonary fibrosis is the primary reason for mortality in patients with paraquat (PQ) poisoning. Our previous study demonstrated that epithelial-mesenchymal transition (EMT) had a role in PQ-induced pulmonary fibrosis. However, the role of endoplasmic reticulum (ER) stress in PQ-induced EMT remains clear. The present study aimed to determine the role of ER stress in EMT in PQ-induced pulmonary fibrosis. A549 and RLE-6TN cells were incubated with LY294002 (a PI3K inhibitor) or transfected with protein kinase RNA-like ER kinase (PERK) small interfering RNA (si) for 24 h prior to being exposed to PQ. Next, the expression levels of ER stress-related proteins, PI3K/AKT/GSK-3β signaling pathway-related proteins and EMT-related markers were analyzed by performing western blotting, reverse transcription-quantitative PCR and immunofluorescence assays. The results of the present study revealed that the protein expression levels of PERK, phosphorylated (p)-PERK, p-eukaryotic initiation factor 2 (eIF2)α were significantly upregulated in the PQ group, whereas p-PI3K, p-AKT and p-GSK-3β were significantly upregulated in the sicontrol + PQ group compared with the sicontrol group. In vitro, following transfection with siPERK or treatment with the PI3K inhibitor, the protein expression levels of E-cadherin (an epithelial marker) were upregulated, whereas the protein expression levels of α-SMA (a mesenchymal marker) were downregulated. Immunofluorescence analysis revealed that the levels of E-cadherin were markedly upregulated, whereas the levels of α-SMA were notably downregulated following transfection with siPERK compared with the sicontrol group. The results of wound healing assay demonstrated that cell migration in the siPERK + PQ group was markedly decreased compared with the sicontrol + PQ group. These indicated that PQ-induced EMT was suppressed after silencing PERK. The expression levels of p-GSK-3β, p-AKT and p-PI3K were also markedly downregulated in the siPERK + PQ group compared with the sicontrol + PQ group. In conclusion, the findings of the present study suggested that ER stress may promote EMT through the PERK signaling pathway in PQ-induced pulmonary fibrosis. Thus, ER stress may represent a potential therapeutic target for PQ-induced pulmonary fibrosis.

Ubiquinone Metabolism and Transcription HIF-1 Targets Pathway Are Toxicity Signature Pathways Present in Extracellular Vesicles of Paraquat-Exposed Human Brain Microvascular Endothelial Cells

Over the last decade, the knowledge in extracellular vesicles (EVs) biogenesis and modulation has increasingly grown. As their content reflects the physiological state of their donor cells, these “intercellular messengers” progressively became a potential source of biomarker reflecting the host cell state. However, little is known about EVs released from the human brain microvascular endothelial cells (HBMECs). The current study aimed to isolate and characterize EVs from HBMECs and to analyze their EVs proteome modulation after paraquat (PQ) stimulation, a widely used herbicide known for its neurotoxic effect. Size distribution, concentration and presence of well-known EV markers were assessed. Identification and quantification of PQ-exposed EV proteins was conducted by data-independent acquisition mass spectrometry (DIA-MS). Signature pathways of PQ-treated EVs were analyzed by gene ontology terms and pathway enrichment. Results highlighted that EVs exposed to PQ have modulated pathways, namely the ubiquinone metabolism and the transcription HIF-1 targets. These pathways may be potential molecular signatures of the PQ-induced toxicity carried by EVs that are reflecting their cell of origin by transporting with them irreversible functional changes.