MAPK pathway mediates epithelial-mesenchymal transition induced by paraquat in alveolar epithelial cells

The Peptide DHα-(4-pentenyl)-ANPQIR-NH2 Exhibits Antifibrotic Activity in Multiple Pulmonary Fibrosis Models Induced by Particulate and Soluble Chemical Fibrogenic Agents

Interstitial lung diseases (ILDs) are a group of restrictive lung diseases characterized by interstitial inflammation and pulmonary fibrosis. The incidence of ILDs associated with exposure to multiple hazards such as inhaled particles, fibers, and ingested soluble chemicals is increasing yearly, and there are no ideal drugs currently available. Our previous research showed that the novel and low-toxicity peptide DHα-(4-pentenyl)-ANPQIR-NH2 (DR3penA) had a strong antifibrotic effect on a bleomycin-induced murine model. Based on the druggability of DR3penA, we sought to investigate its effects on respirable particulate silicon dioxide (SiO2)- and soluble chemical paraquat (PQ)-induced pulmonary fibrosis in this study by using western blot, quantitative reverse-transcription polymerase chain reaction (RT-qPCR), immunofluorescence, H&E and Masson staining, immunohistochemistry, and serum biochemical assays. The results showed that DR3penA alleviated the extent of fibrosis by inhibiting the expression of fibronectin and collagen I and suppressed oxidative stress and epithelial-mesenchymal transition (EMT) in vitro and in vivo. Further study revealed that DR3penA may mitigate pulmonary fibrosis by negatively regulating the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway and mitogen-activated protein kinase (MAPK) pathway. Unexpectedly, through the conversion of drug bioavailability under different routes of administration, DR3penA exerted antifibrotic effects equivalent to those of the positive control drug pirfenidone (PFD) at lower doses. In summary, DR3penA may be a promising lead compound for various fibrotic ILDs. SIGNIFICANCE STATEMENT: Our study verified that DHα-(4-pentenyl)-ANPQIR-NH2 (DR3penA) exhibited positive antifibrotic activity in pulmonary fibrosis induced by silicon dioxide (SiO2) particles and soluble chemical paraquat (PQ) and demonstrated a low-dose advantage compared to the small-molecule drug pirfenidone (PFD). The peptide DR3penA can be further developed for the treatment of multiple fibrotic lung diseases.

Analysis of abnormal expression of signaling pathways in PQ-induced acute lung injury in SD rats based on RNA-seq technology

Background: Paraquat (PQ) plays an important role in agricultural production due to its highly effective herbicidal effect. However, it has led to multiple organ failure in those who have been poisoned, with damage most notable in the lungs and ultimately leading to death. Because of little research has been performed at the genetic level, and therefore, the specific genetic changes caused by PQ exposure are unclear.Methods: Paraquat poisoning model was constructed in Sprague Dawley (SD) rats, and SD rats were randomly divided into Control group, paraquat (PQ) poisoning group and Anthrahydroquinone-2,6-disulfonate (AH2QDS) treatment group. Then, the data was screened and quality controlled, compared with reference genes, optimized gene structure, enriched at the gene expression level, and finally, signal pathways with significantly different gene enrichment were screened.Results: This review reports on lung tissues from paraquat-intoxicated Sprague Dawley (SD) rats that were subjected to RNA-seq, the differentially expressed genes were mainly enriched in PI3K-AKT, cGMP-PKG, MAPK, Focal adhesion and other signaling pathways.Conclusion: The signaling pathways enriched with these differentially expressed genes are summarized, and the important mechanisms mediated through these pathways in acute lung injury during paraquat poisoning are outlined to identify important targets for AH2QDS treatment of acute lung injury due to paraquat exposure, information that will be used to support a subsequent in-depth study on the mechanism of PQ action.

Ferulic acid grafted into β-cyclodextrin nanosponges ameliorates Paraquat-induced human MRC-5 fibroblast injury

Paraquat (PQ) is a commercially important and effective herbicide in the world. Nevertheless, it has higher toxicity causing acute organ damage and different complications, mainly in the lungs and kidneys. Ferulic acid (FA), 4-hydroxy-3-methoxycinnamic acid imposes multiple pharmacological impacts. No protective effect of FA on PQ poisoning-caused human embryonic lung fibroblast damage has not been reported. Despite their many beneficial effects, FA is characterized by poor water solubility, low bioavailability, and phytochemical instability. To solve the problem, β-cyclodextrin nanosponge (β-CD NSs) was utilized to increase the solubility of FA so that it was grafted into β-CD NSs to establish β-CD@FA NSs. The purpose of this work was to examine for the first time the protective effect of β-CD@FA NS on MRC-5 human lung cells damages induced by PQ poisoning. MTS assay was performed to investigate the viability of MRC-5 cells at different concentrations of FA/β-CD@FA NSs when cells were co-cultured with 0.2 μg/mL PQ. The flow cytometry study was carried out to determine apoptosis. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were detected using appropriate biochemistry kits. Compared with the PQ group, the cell activity, CAT, and SOD levels were significantly increased in the FA and chiefly in β-CD@FA NSs intervention groups, whereas apoptosis and MDA levels were markedly decreased. The inflammatory factors tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and interleukin 22 (IL-22) were detected. The results demonstrate that β-CD@FA NSs can inhibit PQ-induced cell damage by enhancing antioxidant stress capacity and regulation of inflammatory responses.

Human Wharton's Jelly Mesenchymal Stem Cell Secretome Modifies the Processes of Neuroprotection and Epithelial-Mesenchymal Transition in Retinal Pigment Epithelium at Transcriptional Level

BACKGROUND

Retinal pigment epithelium (RPE) cells are potential targets for treating retinal detachment (RD) and proliferative vitreoretinopathy (PVR), considering the importance of neuroprotection and epithelial-mesenchymal transition (EMT) of RPE in these conditions. This study investigated the effect of human Wharton's jelly mesenchymal stem cell secretome (WJMSC-S) on the expression of genes involved in both neuroprotection and EMT in RPE cells in vitro (TRKB, MAPK, PI3K, BDNF, and NGF).

METHODS

RPE cells from passages 5-7 were treated with WJMSC-S (or the vehicle culture medium as control) for 24 h at 37◦C and subsequently subjected to RNA extraction and cDNA synthesis. Gene expression level was evaluated using real-time PCR in the treated versus control cells.

RESULTS

The results of our study showed that WJMSC-S led to a significant downregulation in three out of five studied gene expression (MAPK, TRKB, and NGF), and simultaneously, remarkably upregulated the expression of the BDNF gene.

CONCLUSIONS

According to the present data, WJMSC-S can affect the EMT and neuroprotection processes at the mRNA level by suppressing EMT and promoting neuroprotection in RPE cells. This finding may have positive clinical implications in the context of RD and PVR.

MAPKs in the early steps of senescence implemEMTation

Evidence is accumulating that the earliest stages of the DNA damage response can direct cells toward senescence instead of other cell fates. In particular, tightly regulated signaling through Mitogen-Activated Protein Kinases (MAPKs) in early senescence can lead to a sustained pro-survival program and suppress a pro-apoptotic program. Importantly, an epithelial-to-mesenchymal Transition (EMT)-like program appears essential for preventing apoptosis and favoring senescence following DNA damage. In this review, we discuss how MAPKs might influence EMT features to promote a senescent phenotype that increases cell survival at the detriment of tissue function.

Epithelial to mesenchymal transition in mammary gland tissue fibrosis and insights into drug therapeutics

Background

The epithelial-mesenchymal transition (EMT) is a multi-step morphogenetic process in which epithelial cells lose their epithelial properties and gain mesenchymal characteristics. The process of EMT has been shown to mediate mammary gland fibrosis. Understanding how mesenchymal cells emerge from an epithelial default state will aid in unravelling the mechanisms that control fibrosis and, ultimately, in identifying therapeutic targets to alleviate fibrosis.

Methods

The effects of EGF and high glucose (HG) on EMT in mammary epithelial cells, MCF10A and GMECs, as well as their pathogenic role, were studied. In-silico analysis was used to find interacting partners and protein-chemical/drug molecule interactions.

Results

On treatment with EGF and/or HG, qPCR analysis showed a significant increase in the gene expression of EMT markers and downstream signalling genes. The expression of these genes was reduced on treatment with EGF+HG combination in both cell lines. The protein expression of COL1A1 increased as compared to the control in cells treated with EGF or HG alone, but when the cells were treated with EGF and HG together, the protein expression of COL1A1 decreased. ROS levels and cell death increased in cells treated with EGF and HG alone, whereas cells treated with EGF and HG together showed a decrease in ROS production and apoptosis. In-silico analysis of protein-protein interactions suggest the possible role of MAPK1, actin alpha 2 (ACTA2), COL1A1, and NFκB1 in regulating TGFβ1, ubiquitin C (UBC), specificity protein 1 (SP1) and E1A binding protein P300 (EP300). Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment suggests advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE) signalling pathway, relaxin signalling pathway and extra cellular matrix (ECM) receptor interactions underlying fibrosis mechanism.

Conclusion

This study demonstrates that EGF and HG induce EMT in mammary epithelial cells and may also have a role in fibrosis.

Lung microbiome and transcriptome reveal mechanisms underlying PM2.5 induced pulmonary fibrosis

Airborne fine particulate matter (PM_2.5) is considered to be a risk factor for lung fibrosis, and therefore, it has attracted public attention due to its various physicochemical features and its adverse effects on health. However, little remains to be known regarding the mechanism of PM_2.5-induced pulmonary fibrosis. The lung microbiota may be a potential factor involved in the adverse outcomes of pulmonary fibrosis. Meanwhile, miRNAs are thought to be key regulators that participate in the complex interplay between the host and the microbiota. Hence, to investigate the potential mechanisms of pulmonary fibrosis, and to explore the impact of PM_2.5-induced alterations in miRNAs and the lung microbiota and possible interaction patterns in mice models, we took advantage of 16S rDNA gene sequencing, miRNAs sequencing (miRNAs-Seq), and mining of public databases profiling. The results of 16S rDNA analysis showed that PM_2.5 interfered with the microbial community composition, resulting in Proteobacteria becoming an additional dominant phylum. In addition, differentially expressed miRNAs were enriched in HIF-1 signaling, the IL-17 signaling, as well as Th17 cell differentiation pathways, which are closely related to microbial functional pathways. Significantly, a target miRNA, miR-149-5p, may be a key factor triggering the MAPK signal pathway related to pulmonary fibrosis and disturbing the homeostasis of lung bacterial flora. These results indicate that PM_2.5 may lead to interaction between lung microbiota dysbiosis and an imbalance of miRNA levels to form a vicious cycle that promotes lung fibrogenesis. The current study provides new insights into the progression of pulmonary fibrosis.

PTPN3 is a potential target for a new cancer immunotherapy that has a dual effect of T cell activation and direct cancer inhibition in lung neuroendocrine tumor

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PTPN3 suppression associates with lymphocyte activation and cancer suppression.

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PTPN3 is involved in the induction of malignant traits.

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PTPN3 is associated with cellular immunosuppression.

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Signals from PTPN3 go through MAPK and PI3K signaling.

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PTPN3-inhibited lung NET cells enhance PTPN3-suppressed activated lymphocytes.

In our previous study, we found that inhibition of protein tyrosine phosphatase non-receptor type 3 (PTPN3), which is expressed in lymphocytes, enhances lymphocyte activation, suggesting PTPN3 may act as an immune checkpoint molecule. However, PTPN3 is also expressed in various cancers, and the biological significance of PTPN3 in cancer cells is still not well understood, especially for lung neuroendocrine tumor (NET).Therefore, we analyzed the biological significance of PTPN3 in small cell lung cancer and examined the potential for PTPN3 inhibitory treatment as a cancer treatment approach in lung NET including small cell lung cancer (SCLC) and large cell neuroendocrine cancer (LCNEC).

Experiments in a mouse xenograft model using allo lymphocytes showed that PTPN3 inhibition in SCLC cells enhanced the anti-tumor effect of PTPN3-suppressed activated lymphocytes. In addition, PTPN3 was associated with increased vascularization, decreased CD8/FOXP3 ratio and cellular immunosuppression in SCLC clinical specimens. Experiments in a mouse xenograft model using autocrine lymphocytes also showed that PTPN3 inhibition in LCNEC cells augmented the anti-tumor effect of PTPN3-suppressed activated lymphocytes. In vitro experiments showed that PTPN3 is involved in the induction of malignant traits such as proliferation, invasion and migration. Signaling from PTPN3 is mediated by MAPK and PI3K signals via tyrosine kinase phosphorylation through CACNA1G calcium channel. Our results show that PTPN3 suppression is associated with lymphocyte activation and cancer suppression in lung NET. These results suggest that PTPN3 suppression could be a new method of cancer treatment and a major step in the development of new cancer immunotherapies.

The herbicide paraquat-induced molecular mechanisms in the development of acute lung injury and lung fibrosis

The herbicide paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridylium dichloride) is a highly toxic organic heterocyclic herbicide that has been widely used in agricultural settings. Since its commercial introduction in the early 1960s, numerous cases of fatal PQ poisonings attributed to accidental and/or intentional ingestion of PQ concentrated formulations have been reported. The clinical manifestations of the respiratory system during the acute phase of PQ poisoning mainly include acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), followed by pulmonary fibrosis in a later phase. The focus of this review is to summarize the most recent publications related to PQ-induced lung toxicity as well as the underlying molecular mechanisms for PQ-mediated pathologic processes. Growing sets of data from in vitro and in vivo models have demonstrated the involvement of the PQ in regulating lung oxidative stress, inflammatory response, epigenetics, apoptosis, autophagy, and the progression of lung fibrosis. The article also summarizes novel therapeutic avenues based on a literature review, which can be explored as potential means to combat PQ-induced lung toxicity. Finally, we also presented clinical studies on the association of PQ exposure with the incidence of lung injury and pulmonary fibrosis.

Role of epithelial-to-mesenchymal transition in the pulmonary fibrosis induced by paraquat in rats

BACKGROUND

This study aims to explore the characteristics of the epithelial-to-mesenchymal transition (EMT) process and its underlying molecular mechanisms in the period of paraquat (PQ)-induced pulmonary fibrosis (PF).

METHODS

Picrosirius red staining and collagen volume fraction were utilized to evaluate the pathological changes of PQ-induced PF in rats. Immunohistochemistry, Western blot, and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) were used to measure the protein and gene expression of EMT markers, EMT-associated transcription factors, and regulators of EMT-related pathways, respectively.

RESULTS

The collagen deposition in the alveolar septum and increased PF markers were characteristics of pathological changes in PQ-induced PF, reached a peak on day 14 after PQ poisoning, and then decreased on day 21. The protein and gene expression of the fibrosis marker, EMT markers, transcription factors, and regulators of EMT-related signaling pathways significantly increased at different time points after PQ poisoning compared with corresponding controls (P<0.05), and most of them reached a peak on day 14, followed by a decrease on day 21. The gene expression of EMT markers was significantly correlated with PF markers, transcription factors, and regulators of EMT-related signaling pathways (P<0.05). The mRNA expression of transcription factors was significantly correlated with that of TGF-β1 and Smad2 (P<0.05 or P<0.01), instead of Wnt2 and β-catenin (P>0.05).

CONCLUSIONS

EMT process plays a role in the PQ-induced PF, in which most PF and EMT markers have a peak phenomenon, and its underlying molecular mechanisms might be determined by further studies.

Repeated radon exposure induced lung injury and epithelial-mesenchymal transition through the PI3K/AKT/mTOR pathway in human bronchial epithelial cells and mice

Radon exposure is the most frequent cause of lung cancer in non-smokers. The high linear energy transfer alpha-particles from radon decay cause the accumulation of multiple genetic changes and lead to cancer development. Epithelial-mesenchymal transition (EMT) plays an important role in oncogenesis. However, the mechanisms underlying chronic radon exposure-induced EMT attributed to carcinogenesis are not understood. This study aimed to explore the EMT and potential molecular mechanisms induced by repeated radon exposure. The EMT model of 16HBE and BEAS-2B cells was established with radon exposure (20000 Bq/m³, 20 min each time every 3 days). We found repeated radon exposure facilitated epithelial cell migration, proliferation, reduced cell adhesion and ability to undergo EMT through a decrease in epithelial markers and an increase in mesenchymal markers. Radon regulated the expression of matrix metalloproteinase 2 (MMP2) and tissue inhibitors of metalloproteinase 2 (TIMP2) to disrupt the balance of MMP2/TIMP2. In vivo, BALB/c mice were exposed to 10⁵ Bq/m³ radon gas for cumulative doses of 60 and 120 Working Level Months (WLM). Radon inhalation caused lung damage and fibrosis in mice, which was aggravated with the increase of exposure dose. EMT-like transformation also occurred in lung tissues of radon-exposure mice. Moreover, radon radiation increased p-PI3K, p-AKT and p-mTOR in cells and mice. Radon reduced the GSK-3β level and elevated the active β-catenin in 16HBE cells. The m-TOR and AKT inhibitors attenuated radon exposure-induced EMT by regulation related biomarkers. These data demonstrated that radon exposure induced EMT through the PI3K/AKT/mTOR pathway in epithelial cells and lung tissue.

The MUC5B Mucin Is Involved in Paraquat-Induced Lung Inflammation

Objective

Paraquat (PQ), a widely used toxic herbicide, induces lung inflammation through mechanisms that remain incompletely understood. In a previous study, we found that the plasma MUC5B mucin level was implicated in PQ poisoning in patients. Here, we hypothesize that MUC5B is a critical mediator in PQ-induced cell inflammation.

Methods

A mouse model of PQ-induced lung injury was used to examine the MUC5B expression level. A549 cells (alveolar epithelial cells line) were exposed to PQ in dose-dependent and time-dependent manners. Cell viability was detected by CCK-8 assays. The expression levels of MUC5B were examined by dot blot enzyme-linked immunosorbent assay (ELISA) and RT-qPCR. Western blotting was used to detect the levels of proteins in the MAPK and NF-κB pathways. Inflammatory factors in the cell culture medium were measured by ELISA. NF-κB and MAPK pathway inhibitors and MUC5B siRNA (siMUC5B) were used to determine the function of MUC5B. Finally, N-acetyl-cysteine (NAC) was added and its regulatory effect on the MAPK-NF-κB-MUC5B pathway was examined in PQ-induced cell inflammation.

Results

MUC5B was significantly upregulated accompanying the increases in TNF-α and IL-6 secretion following PQ treatment in mouse and also in A549 cells after treatment with 50 μM PQ at 24 hours. Furthermore, MAPK and NF-κB pathway inhibitors could dramatically decrease the expression of MUC5B and the secretion of TNF-α and IL-6. Importantly, siMUC5B could significantly attenuate the secretion of TNF-α and IL-6 induced by PQ. As expected, the addition of NAC efficiently suppresses the TNF-α and IL-6 secretion stimulated from PQ and also downregulated ERK, JNK, and p65 phosphorylation (ERK/JNK MAPK and NF-κB pathways) as well as MUC5B expression.

Conclusion

Our findings suggest that MUC5B participates in the process of PQ-induced cell inflammation and is downstream of the NF-κB and MAPK pathways. NAC can attenuate PQ-induced cell inflammation at least in part by suppressing the MAPK-NF-κB-MUC5B pathway. These results nominate MUC5B as a new biomarker and therapeutic target for PQ-induced lung inflammation.

Pomegranate extract inhibits migration and invasion of oral cancer cells by downregulating matrix metalloproteinase-2/9 and epithelial-mesenchymal transition

Discovering drug candidates for the modulation of metastasis is of great importance in inhibiting oral cancer malignancy. Although most pomegranate extract applications aim at the antiproliferation of cancer cells, its antimetastatic effects remain unclear, especially for oral cancer cells. The aim of this study is to evaluate the change of two main metastasis characters, migration and invasion of oral cancer cells. Further, we want to explore the molecular mechanisms of action of pomegranate extract (POMx) at low cytotoxic concentration. We found that POMx ranged from 0 to 50 μg/mL showing low cytotoxicity to oral cancer cells. In the case of oral cancer HSC-3 and Ca9-22 cells, POMx inhibits wound healing migration, transwell migration, and matrix gel invasion. Mechanistically, POMx downregulates matrix metalloproteinase (MMP)-2 and MMP-9 activities and expressions as well as epithelial-mesenchymal transition (EMT) signaling. POMx upregulates extracellular signal-regulated kinases 1/2 (ERK1/2), but not c-Jun N-terminal kinase (JNK) and p38 expression. Addition of ERK1/2 inhibitor (PD98059) significantly recovered the POMx-suppressed transwell migration and MMP-2/-9 activities in HSC-3 cells. Taken together, these findings suggest to further test low cytotoxic concentrations of POMx as a potential antimetastatic therapy against oral cancer cells.

Bioinformatic analysis reveals the importance of epithelial-mesenchymal transition in the development of endometriosis

Background: Endometriosis is a frequently occurring disease in women, which seriously affects their quality of life. However, its etiology and pathogenesis are still unclear. Methods: To identify key genes/pathways involved in the pathogenesis of endometriosis, we recruited 3 raw microarray datasets (GSE11691, GSE7305, and GSE12768) from Gene Expression Omnibus database (GEO), which contain endometriosis tissues and normal endometrial tissues. We then performed in-depth bioinformatic analysis to determine differentially expressed genes (DEGs), followed by gene ontology (GO), Hallmark pathway enrichment and protein-protein interaction (PPI) network analysis. The findings were further validated by immunohistochemistry (IHC) staining in endometrial tissues from endometriosis or control patients. Results: We identified 186 DEGs, of which 118 were up-regulated and 68 were down-regulated. The most enriched DEGs in GO functional analysis were mainly associated with cell adhesion, inflammatory response, and extracellular exosome. We found that epithelial-mesenchymal transition (EMT) ranked first in the Hallmark pathway enrichment. EMT may potentially be induced by inflammatory cytokines such as CXCL12. IHC confirmed the down-regulation of E-cadherin (CDH1) and up-regulation of CXCL12 in endometriosis tissues. Conclusions: Utilizing bioinformatics and patient samples, we provide evidence of EMT in endometriosis. Elucidating the role of EMT will improve the understanding of the molecular mechanisms involved in the development of endometriosis.

The Prospect of Identifying Resistance Mechanisms for Castrate-Resistant Prostate Cancer Using Circulating Tumor Cells: Is Epithelial-to-Mesenchymal Transition a Key Player?

Prostate cancer (PCa) is initially driven by excessive androgen receptor (AR) signaling with androgen deprivation therapy (ADT) being a major therapeutic approach to its treatment. However, the development of drug resistance is a significant limitation on the effectiveness of both first-line and more recently developed second-line ADTs. There is a need then to study AR signaling within the context of other oncogenic signaling pathways that likely mediate this resistance. This review focuses on interactions between AR signaling, the well-known phosphatidylinositol-3-kinase/AKT pathway, and an emerging mediator of these pathways, the Hippo/YAP1 axis in metastatic castrate-resistant PCa, and their involvement in the regulation of epithelial-mesenchymal transition (EMT), a feature of disease progression and ADT resistance. Analysis of these pathways in circulating tumor cells (CTCs) may provide an opportunity to evaluate their utility as biomarkers and address their importance in the development of resistance to current ADT with potential to guide future therapies.

Diosgenin inhibits the epithelial-mesenchymal transition initiation in osteosarcoma cells via the p38MAPK signaling pathway

Diosgenin is an important basic raw material for the production of steroid hormone drugs. It can be isolated and purified from a variety of traditional Chinese medicines or plants. Modern molecular biological studies have shown that diosgenin inhibits various tumor cells migration and invasion ability to varying degrees in vitro and in vivo. The aim of the present study was to observe the inhibitory effects of diosgenin on the invasive and metastatic capabilities of osteosarcoma cells and to determine the association between the effects of diosgenin on the epithelial-mesenchymal transition (EMT). Wound healing and Transwell assays were used to observe the inhibitory effects of diosgenin on the invasion and migration of two osteosarcoma cell lines. Immunofluorescence was used to observe changes in transforming growth factor β1 (TGF-β1) protein expression levels in the osteosarcoma cells following drug administration. EMT-associated proteins, including TGFβ1, E-cadherin and vimentin were detected by western blotting, which demonstrated that the drug may inhibit the initiation of EMT in osteosarcoma cells. Western blot analysis of the expression of all the proteins in the mitogen-activated protein kinase (MAPK) pathway demonstrated that the drug inhibited the MAPK signaling pathway. The primary mechanism of action of diosgenin was the inhibition of the phosphorylated p38 (pP38) protein. Through a combination of inhibitors of the p38MAPK signaling pathway and detection of the downstream EMT marker protein E-cadherin by quantitative PCR, pP38 was confirmed to be a target of diosgenin in the inhibition of EMT in the osteosarcoma cells via the MAPK molecular signaling pathway. Diosgenin may exhibit utility as an auxiliary drug for the clinical reduction of metastasis in patients with osteosarcoma.

Gremlin is a potential target for posterior capsular opacification

Objective: The present study was conducted to determine the role of gremlin during the development of posterior capsular opacification (PCO) via in vitro and in vivo experiments. Methods: The activation, roles and relationships of the BMPs/Smad1/5, MAPK, FAK and AKT signaling pathways in human lens epithelial cells (HLECs) after gremlin induction were detected by western blotting and real-time PCR. Wound-healing, transwell, capsular bag models and rat PCO models assays were used to test the effects of gremlin on HLECs' migration, proliferation, EMT-specific protein α-smooth muscle actin（α-SMA）and development of PCO in rats. Results: Our data showed that knockdown of the gremlin inhibited the development of PCO and reduced expression of α-SMA in rats. While gremlin did not alter the migration of HLECs, it increased the expression of p-ERK and p-AKT. Knockout of Smad2 or Smad3 inhibited the expression of p-ERK and p-AKT proteins induced by gremlin. Gremlin also reduced BMP4-induced expression of the p-Smad1/5 protein. Finally, knockout of Smad1/5 increased gremlin-induced expression of α-SMA, fibronectin and type I collagen (COL-1) in HLECs. Conclusion: These results suggested that gremlin contributed to the development of PCO by promoting LEC proliferation, activation of TGF-β/Smad, ERK and AKT signaling and inhibition of BMPs/Smad1/5 signaling. Furthermore, inhibiting gremlin effectively impaired both PCO development in rats and EMT in the lens capsule. Thus, our data suggest that gremlin might be a potential target for PCO.

Protective Effect of Anthocyanin on Paraquat-Induced Apoptosis and Epithelial-Mesenchymal Transition in Alveolar Type II Cells

BACKGROUND Paraquat (PQ) can over-accumulate in alveolar epithelial cells. Anthocyanin (An) can exert anti-oxidative properties. The role of An in PQ-induced toxicity is unclear, so we aimed to explore whether An could inhibit epithelial mesenchymal transition (EMT) induced by PQ in alveolar cells. MATERIAL AND METHODS lveolar epithelial cells were treated with PQ and An with concentration gradient for 12, 24, and 48 h. The cell viability, ROS level, and apoptosis rate were determined using the Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. The lactate dehydrogenase (LDH) leakage, methane dicarboxylic aldehyde (MDA) level, glutathione peroxidase (GPx), and superoxide dismutase (SOD) activities were determined by spectrophotometric method. The mRNA and protein expressions were detected using quantitative real-time PCR (qPCR) and Western blot, respectively. RESULTS An reduced the PQ-induced apoptosis in a dose-dependent manner. Moreover, An reduced the ratio of Bax/Bcl-2 to ROS level. We found that An suppressed the activity of LDH and MDA and improved SOD and GPX levels. Additionally, the level of PQ-induced E-cadherin was decreased by An while the expressions of vimentin, α-smooth muscle actin (α-SMA), and collagens type I (col-I) were increased. Furthermore, An inhibited the levels of transforming growth factor β1 (TGF-β1) and activin receptor-like kinase 5 (ALK5) and reduced the phosphorylation of smad2. CONCLUSIONS Our study shows newly discovered effects of anthocyanidins on EMT and supports their chemopreventive effects in paraquat-induced apoptosis in alveolar type II cells.

Beneficial effects of ascorbic acid to treat lung fibrosis induced by paraquat

Paraquat (PQ) is one of the most widely employed herbicides that is used worldwide and it causes severe toxic effects in humans and animals. A PQ exposition can lead to pulmonary fibrosis (PF) and the mechanisms seem to be linked to oxidative stress, although other pathways have been suggested. Antioxidants can be useful as a therapy, although interventions with this kind of system are still controversial. Hence, this study has investigated the role of ascorbic acid (vitamin C) post-treatment on PQ-induced PF in male C57/BL6 mice. Pulmonary fibrosis was induced by a single PQ injection (10mg/kg; i.p.). The control group received a PQ vehicle. Seven days after the PQ or vehicle injections, the mice received vitamin C (150 mg/kg, ip, once a day) or the vehicle, over the following 7 days. Twenty-four hours after the last dose of vitamin C or the vehicle, the mice were euthanized and their bronchoalveolar lavage fluid (BALF) and their lungs were collected. The data obtained showed that vitamin C reduced the cellular recruitment, the secretion of IL-17 –a cytokine involved in neutrophils migration, TGF-β–a pro-fibrotic mediator and the collagen deposition. Moreover, vitamin C elevated the superoxide dismutase (SOD) and catalase levels, both antioxidant enzymes, but it did not alter the tracheal contractile response that was evoked by methacholine. Therefore, the researchers have highlighted the mechanisms of vitamin C as being non-invasive and have suggested it as a promising tool to treat lung fibrosis when it is induced by a PQ intoxication.

Isorhamnetin protects against bleomycin-induced pulmonary fibrosis by inhibiting endoplasmic reticulum stress and epithelial-mesenchymal transition

The present study aimed to determine whether isorhamnetin (Isor), a natural antioxidant polyphenol, has antifibrotic effects in a murine model of bleomycin-induced pulmonary fibrosis. A C57 mouse model of pulmonary fibrosis was established by intraperitoneal injection of a single dose of bleomycin (3.5 U/kg), and then Isor (10 and 30 mg/kg) was administered intragastrically. The level of fibrosis was assessed by hematoxylin and eosin and Sirius red staining. α-smooth muscle actin and type I collagen levels in lung tissues were determined by western blotting and immunohistochemistry (IHC). Epithelial-mesenchymal transition (EMT), endoplasmic reticulum stress (ERS) and related signaling pathways were examined by western blotting and IHC. In vitro, human bronchial epithelial cells (HBECs) and A549 cells were treated with transforming growth factor (TGF)β1 with or without Isor, and collagen deposition and the expression levels of EMT- and ERS-related genes or proteins were analyzed by reverse transcription-quantitative polymerase chain reaction, western blotting, and immunofluorescence. The results demonstrated that Isor inhibited bleomycin-induced collagen deposition, reduced type I collagen and α-SMA expression, and alleviated EMT and ERS in vivo. Furthermore, incubation of HBECs and A549 cells with TGFβ1 activated EMT and ERS, and this effect was reversed by Isor. In conclusion, Isor treatment attenuated bleomycin-induced EMT and pulmonary fibrosis and suppressed bleomycin-induced ERS and the activation of PERK signaling.

A review of current studies on cellular and molecular mechanisms underlying pulmonary fibrosis induced by chemicals

Several studies showed that the inflammatory and fibrotic responses induced by polyhexamethylene guanidine phosphate (PHMG-p) were similar to those observed for idiopathic pulmonary fibrosis in South Korea in 2011. "Omic" technologies can be used to understand the mechanisms underlying chemical-induced diseases. Studies to determine the toxicity of chemicals may facilitate understanding of the mechanisms underlying the development of pulmonary fibrosis at a molecular level; thus, such studies may provide information about the toxic characteristics of various substances. In this review, we have outlined the cellular and molecular mechanisms underlying idiopathic pulmonary fibrosis and described pulmonary fibrosis induced by various chemicals, including bleomycin, paraquat, and PHMG-p, based on the results of studies performed to date.

Determination of LCt50 of aerosolized paraquat and its pulmonary toxic implications in non-anesthetized rats

Paraquat (PQ), a highly popular agricultural herbicide, is a serious occupational hazard with lethality reported at doses as low as 35 mg/kg body weight with intoxication occurring via inhalation or dermal route. The main objective of this study was to determine the median lethal concentration (LCt₅₀) of paraquat through whole body exposure in adult male Wistar rats. Aerosolized PQ dissolved in water was delivered in a dose-dependent manner, to fully conscious rats confined in whole body plethysmograph (WBP), in a nebulized form with concentrations ranging from 40-200 mg/kg of air over a 4 h exposure period. Animals were observed up to 24-48 h post-exposure to observe any lethality. LCt₅₀ estimates (±95% confidence interval) were obtained from the sequential stage-wise experiments using probit analysis. Rat lungs were examined radiologically and histopathologically. Gas chromatography-mass spectrometry (GC-MS) analysis determined the correlation of PQ accumulation in the lungs with the actual exposed dose of PQ. The actual LCt₅₀ was found to be 218 g·min/m³ whereas 57.9 ± 2.90 µg/g of PQ accumulated in the lungs of each lifeless animal. All animals exhibited severe respiratory changes and pulmonary abnormalities. This study demonstrated that when compared with the actually exposed dose, the amount of PQ that accumulated in the lungs was very low, but enough to cause death in 50% of animal population and cause pulmonary abnormalities in each of the experimental animal. The PQ exposure carried out in WBP also facilitated the dermal absorption of aerosolized PQ, which replicated the real-life situation in workers operating with PQ.

JNK Inhibitor SP600125 Attenuates Paraquat-Induced Acute Lung Injury: an In Vivo and In Vitro Study

Acute lung injury (ALI) is a major complication soon after paraquat poisoning and rapidly progresses with high mortality. However, the specific mechanism underlying paraquat-induced ALI is still unclear. In this study, the mechanism underlying the protective effects of SP600125 on paraquat-induced ALI was investigated according to oxidative stress, inflammation, and apoptosis. The rats were randomly assigned into the control group (CON), the paraquat poisoning group (PQ), and the PQ + SP600125 group (SP). A549 cells were divided into the Con group, Pq group, and Sp group. H&E staining and detection of lung wet/dry ratio were employed to evaluate lung injury. Annexin V-PI staining was done to evaluate A549 cell apoptosis. Dihydroethidium fluorescence was used to measure reactive oxygen species (ROS) in the lungs and A549 cells. ELISA was performed to detect TNF-α and IL-6 in the supernatant of bronchoalveolar lavage fluid (BALF) and A549 cells. RT-qPCR was done to measure the messenger RNA (mRNA) expression of TNF-α and IL-6 in the lungs and A549 cells. Western blotting assay was performed to detect the protein expression of phospho-JNK, total JNK, and cleaved caspase-3. Electrophoretic mobility shift assay was employed to detect the DNA binding activities of AP-1 and P-p65. JNK inhibitor SP600125 reduced JNK phosphorylation, downregulated cleaved caspase-3 protein level, decreased AP-1 transcriptional activity and ROS level, and reduced the transcription and expression of TNF-α and IL-6, which improved ALI and cell apoptosis after paraquat poisoning. Our results indicate that JNK/AP-1 mediates ALI as well as oxidative stress and inflammation deterioration secondary to paraquat poisoning.

CTGF Contributes to the Development of Posterior Capsule Opacification: an in vitro and in vivo study

Connective tissue growth factor (CTGF) is a crucial factor that plays a major role in the process of posterior capsule opacification (PCO). However, the effects of CTGF on the proliferation and migration of lens epithelial cells (LECs) and on the mechanism of the epithelial mesenchymal transition (EMT) and extracellular matrix (ECM) in human lens epithelial cells (HLECs) as well as the effects of shRNA-mediated CTGF knockdown on the development of PCO in rats remain unclear. In the present study, we found that CTGF promoted EMT, proliferation, migration and the expression of p-ERK1/2 protein in HLECs but exerted little effect on the expression of p-p38 and p-JNK1/2 proteins. MEK inhibitor U0126 effectively restrained the CTGF-induced expression of α-smooth muscle actin (α-SMA), fibronectin (Fn) and type I collagen (COL-1) in HLECs. CTGF knockdown effectively postponed the onset of PCO in the rats and significantly reduced the expression of α-SMA in the capsule. In conclusion, CTGF contributed to the development of PCO presumably by promoting proliferation, migration of LECs, EMT specific protein expression and ECM synthesis in HLECs, which is dependent on ERK signalling. Furthermore, blocking CTGF effectively inhibited PCO in the rats and the EMT specific protein expression in the lens capsule.

Integrated long non-coding RNA analyses identify novel regulators of epithelial-mesenchymal transition in the mouse model of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic fatal lung disease characterized by aberrant accumulation of fibroblast population and deposition of extra cellular matrix. Increasing evidence support that epithelial‐mesenchymal transition (EMT) of alveolar epithelial cells is a critical process in the pathogenesis of IPF. Although delivery of bleomycin to induce acute lung injury is the most well‐studied animal model of pulmonary fibrosis, there is considerable interest to pursue other models to understand the common and/or specific pathological mechanisms. In this study, we established a mouse model of pulmonary injury and progressive interstitial fibrosis via intraperitoneal injection of paraquat, a widely used herbicide known to cause pulmonary fibrosis in human. Using transcriptome sequencing and microarray analysis, we profiled expression of long non‐coding RNAs (lncRNAs) and identified 513 up‐regulated and 204 down‐regulated lncRNAs in paraquat‐induced fibrotic lung tissues. Gene ontology analysis revealed that the differentially expressed lncRNAs are implicated in cell differentiation, epithelium morphogenesis and wound healing, pathways closely associated with EMT. Furthermore, we identified the evolutionally conserved target genes of two up‐regulated lncRNAs, uc.77 and 2700086A05Rik, as Zeb2 and Hoxa3, respectively, both of which are important modulators of EMT. Consistently, overexpression of uc.77 or 2700086A05Rik in human lung epithelial cells induced EMT as demonstrated by changes in gene and protein expression of various EMT markers and cell morphology. Collectively, our results uncovered a crucial role of lncRNA in the regulation of EMT during lung fibrosis and provide potential avenues for the discovery of novel molecular markers and therapeutic targets for IPF.