Dual role of RACK1 in airway epithelial mesenchymal transition and apoptosis

Scutellarin Alleviates Ovalbumin-Induced Airway Remodeling in Mice and TGF-β-Induced Pro-fibrotic Phenotype in Human Bronchial Epithelial Cells via MAPK and Smad2/3 Signaling Pathways

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness (AHR), inflammation, and remodeling. Epithelial-mesenchymal transition (EMT) is an essential player in these alterations. Scutellarin is isolated from Erigeron breviscapus. Its vascular relaxative, myocardial protective, and anti-inflammatory effects have been well established. This study was designed to detect the biological roles of scutellarin in asthma and its related mechanisms. The asthma-like conditions were induced by ovalbumin challenges. The airway resistance and dynamic compliance were recorded as the results of AHR. Bronchoalveolar lavage fluid (BALF) was collected and processed for differential cell counting. Hematoxylin and eosin staining, periodic acid-Schiff staining, and Masson staining were conducted to examine histopathological changes. The levels of asthma-related cytokines were measured by enzyme-linked immunosorbent assay. For in vitro analysis, the 16HBE cells were stimulated with 10 ng/mL transforming growth beta-1 (TGF-β1). Cell migration was estimated by Transwell assays and wound healing assays. E-cadherin, N-cadherin, and α-smooth muscle actin (α-SMA) were analyzed by western blotting, real-time quantitative polymerase chain reaction, immunofluorescence staining, and immunohistochemistry staining. The underlying mechanisms of the mitogen-activated protein kinase (MAPK) and Smad pathways were investigated by western blotting. In an ovalbumin-induced asthmatic mouse model, scutellarin suppressed inflammation and inflammatory cell infiltration into the lungs and attenuated AHR and airway remodeling. Additionally, scutellarin inhibited airway EMT (upregulated E-cadherin level and downregulated N-cadherin and α-SMA) in ovalbumin-challenged asthmatic mice. For in vitro analysis, scutellarin prevented the TGF-β1-induced migration and EMT in 16HBE cells. Mechanistically, scutellarin inhibits the phosphorylation of Smad2, Smad3, ERK, JNK, and p38 in vitro and in vivo. In conclusion, scutellarin can inactivate the Smad/MAPK pathways to suppress the TGF-β1-stimulated epithelial fibrosis and EMT and relieve airway inflammation and remodeling in asthma. This study provides a potential therapeutic strategy for asthma.

Quantitative proteome and lysine succinylome characterization of zinc chloride smoke-induced lung injury in mice

The inhalation of zinc chloride (ZnCl2) smoke is one of common resources of lung injury, potentially resulting in severe pulmonary complications and even mortality. The influence of ZnCl2 smoke on lysine succinylation (Ksucc) in the lungs remains uncertain. In this study, we used a ZnCl2 smoke inhalation mouse model to perform global proteomic and lysine succinylome analyses. A total of 6781 Ksucc sites were identified in the lungs, with injured lungs demonstrating a reduction to approximately 2000 Ksucc sites, and 91 proteins exhibiting at least five differences in the number of Ksucc sites. Quantitative analysis revealed variations in expression of 384 proteins and 749 Ksucc sites. The analysis of protein-protein interactions was conducted for proteins displaying differential expression and differentially expressed lysine succinylation. Notably, proteins with altered Ksucc exhibited increased connectivity compared with that in differentially expressed proteins. Beyond metabolic pathways, these highly connected proteins were also involved in lung injury-associated pathological reactions, including processes such as focal adhesion, adherens junction, and complement and coagulation cascades. Collectively, our findings contribute to the understanding of the molecular mechanisms underlaying ZnCl2 smoke-induced lung injury with a specific emphasis on lysine succinylation. These findings could pave the way for targeted interventions and therapeutic strategies to mitigate severe pulmonary complications and mortality associated with such injuries in humans.

The Interaction of OTUB1 and TRAF3 Mediates NLRP3 Inflammasome Activity to Regulate TGF-β1-induced BEAS-2B Cell Injury

Asthma is a frequently chronic respiratory disease with inflammation and remodeling in the airway. OTUB1 has been reported to be associated with pulmonary diseases. However, the role and potential mechanism of OTUB1 in asthma remain unclear. The expressions of OTUB1 in the bronchial mucosal tissues of asthmatic children and TGF-β1-induced BEAS-2B cells were determined. The biological behaviors were assessed in an asthma in vitro model using a loss-function approach. The contents of inflammatory cytokines were detected by ELISA kits. The related protein expressions were performed using western blot assay. Besides, the interaction between OTUB1 and TRAF3 was detected by Co-IP and ubiquitination assays. Our results showed that OTUB1 level was increased in asthmatic bronchial mucosal tissues and TGF-β1-induced BEAS-2B cells. OTUB1 knockdown promoted proliferation, inhibited apoptosis and EMT of TGF-β1-treated cells. The inhibition of OTUB1 attenuated the TGF-β1-induced inflammation and remodeling. Furthermore, OTUB1 knockdown inhibited the deubiquitination of TRAF3 and further suppressed the activation of NLRP3 inflammasome. The overexpression of TRAF3 or NLRP3 reversed the positive role of OTUB1 knockdown in TGF-β1-induced cells injury. Collectively, OTUB1 deubiquitinates TRAF3 to activate NLRP3 inflammasome, thereby leading to inflammation and remodeling of TGF-β1-induced cells, and further promoting the pathogenesis of asthma.

Azithromycin suppresses TGF-β1-related epithelial-mesenchymal transition in airway epithelial cells via targeting RACK1

Transforming growth factor-β1 (TGF-β1) associated epithelial-mesenchymal transition (EMT) contributes to multiple respiration diseases via Smad or MAPKs pathway. Our previous study has demonstrated that the typical macrolide antibiotic, azithromycin (AZM) played a notable anti-EMT role in ovalbumin (OVA)-challenged mice. However, the precise mechanism of AZM on TGF-β1 mediated EMT in bronchial epithelial cells is still unclear. The purpose of this study was to elucidate whether azithromycin targeting RACK1 inhibits TGF-β1 mediated EMT in vitro. The results showed that AZM significantly inhibited the expression of RACK1 and the activation of the downstream JNK, ERK, and Smad3 signaling pathways, thereby suppressing the migration of bronchial epithelial cells and reversing the TGF-β1-induced EMT. The effect of AZM on TGF-β1 mediated EMT in vitro is dependent on the dose of AZM. Although RACK1 has been shown to regulate IRE1α expression with siRACK1 transfection, there was no direct interaction between IRE1α and AZM. On the contrary, weak interaction between AZM and RACK1 was predicted with molecular docking. In summary, AZM targets RACK1 to trigger downstream JNK, ERK, and Smad3 signaling pathways and is an effective anti-EMT drug for bronchial epithelial cells in a dose-dependent manner.

Inorganic arsenic promotes apoptosis of human immortal keratinocytes through the TGF-β1/ERK signaling pathway

Chronic exposure to high-dose inorganic arsenic through groundwater, air, or food remains a major environmental public health issue worldwide. Apoptosis, a method of cell death, has recently become a hot topic of research in biology and medicine. Previous studies have demonstrated that extracellular signal-regulated kinase (ERK) is related to arsenic-induced apoptosis. However, the reports are contradictory, and the knowledge of the above-mentioned mechanisms and their mutual regulation remains limited. In this study, the associations between the TGF-β1/ERK signaling pathway and arsenic-induced cell apoptosis were confirmed using the HaCaT cell model. The relative expressions of the indicators of the TGF-β1/ERK signaling pathway, apoptosis-related genes (cytochrome C, caspase-3, caspase-9, cleaved caspase-3, cleaved caspase-9, and Bax), the mitochondrial membrane potential, and the total apoptosis rate were significantly increased (P < .05), while the expression of the antiapoptosis gene Bcl-2 was significantly decreased (P < .05) in cells of the group exposed to arsenic. Moreover, the results demonstrated that the ERK inhibitor (PD98059) and TGF-β1 inhibitor (LY364947) could inhibit the activation of the ERK signaling pathway, thereby reducing the mitochondrial membrane potential, the total apoptosis rate, and the expression of pro-apoptosis-related genes in the cells, while the expression of the antiapoptosis gene Bcl-2 was significantly increased (P < .05). By contrast, the recombinant human TGF-β1 could promote apoptosis of the HaCaT cells by increasing the activation of the ERK signaling pathway (P < .05). These results indicate that inorganic arsenic promotes the apoptosis of human immortal keratinocytes through the TGF-β1/ERK signaling pathway.

A Network Pharmacology Approach to Reveal the Underlying Mechanisms of Rhizoma Dioscoreae Nipponicae in the Treatment of Asthma

Background

In this study, network pharmacological methods were used to analyze the targets of Rhizoma Dioscoreae Nipponicae (RDN) and investigate the potential underlying mechanism of RDN in the treatment of asthma.

Methods

Asthma-related targets were obtained from the GeneCards and DisGeNET databases. The bioactive components of RDN were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform database, and the targets of these compounds were predicted using the BATMAN-TCM database. The network of RDN component targets was constructed using Cytoscape. A protein-protein interaction (PPI) network was constructed in Cytoscape to determine the potential targets of RDN for the treatment of asthma. The hub genes of RDN in the treatment of asthma were screened using network topological parameters. Gene ontology (GO) and the KEGG pathways were analyzed. Molecular docking and in vivo experiments were performed to validate the network pharmacology results.

Results

A total of four bioactive components and 55 targets were identified. The results of the enrichment analysis suggested that the treatment of asthma with RDN involved signaling pathways, such as those related to systemic lupus erythematosus, alcoholism, viral carcinogenesis, the cell cycle, prostate cancer, transcriptional misregulation in cancer, hepatitis B, thyroid hormone signaling, and PI3K-AKT signaling, as well as other signaling pathways. Molecular docking showed that the active components of RDN could stably bind to the predicted target. In vivo experiments showed that RDN could regulate the expression of target genes and inhibit the activation of the PI3K-AKT signaling pathway.

Conclusion

To a certain extent, this study reveals the potential bioactive components and molecular mechanisms of RDN in the treatment of asthma and provides new insights for the development of new drugs for asthma.

The Role of Osthole on TGF-β-Induced Lung Epithelium Apoptosis Injury and Epithelial-Mesenchymal Transition-Mediated Airway Remodeling in Pediatric Asthma

Osthole, a coumarin compound derived from Fructus Cnidii, exerts anti-inflammatory effects in an asthma model. But the effect of osthole on epithelial injury and epithelial-mesenchymal transition (EMT) in asthma remains unclear. 16HBE cells were incubated with TGF-β1 with or without osthole in vitro. Ovalbumin (OVA)-induced asthmatic mouse model was established in vivo. Cell counting kit-8 was carried out to evaluate the viability of 16HBE cells. The impact of osthole on TGF-β1-evoked cell apoptosis and EMT process was measured by flow cytometry based on Annexin V-FITC/PI staining, transwell assay, immunofluorescence, and Western blot. The regulatory role of osthole in TGF-β1/Smad and p38, ERK1/2, and JNK MAPK signaling was detected via Western blot. Osthole treatment significantly suppressed TGF-β1-induced 16HBE cell apoptosis, verified by a reduced percentage of apoptotic cells, decreased expression of proapoptotic proteins (cleaved-caspase3 and Bax), and enhanced antiapoptotic factor (Bcl-2) expression. In addition, the promotive impact of TGF-β1 on the migration of 16HBE cells was reversed by osthole, accompanied by elevated E-cadherin expression and reduced Snail and N-cadherin expression. The activation of the Smad2/3 and MAPKs pathway evoked by TGF-β1 was inhibited by osthole in 16HBE cells. We also found that osthole mitigated airway epithelium injury and subepithelial fibrosis in OVA-challenged asthmatic mice in vivo. Osthole could mitigate TGF-β1-induced epithelial cell injury and EMT process by suppressing the activation of MAPK and Smad2/3 pathways separately. Our present study showed a new insight into understanding the underlying mechanism of osthole injury on epithelium injury and subepithelial fibrosis in airway remodeling. Asthma, epithelial injury, epithelial-mesenchymal transition, and airway remodeling are the effects of osthole on airway remodeling.

USP41 promotes breast cancer via regulating RACK1

Background

Breast cancer (BC) is the most common cancer diagnosed among women and is the second leading cause of cancer death. It is of great significance to explore potential candidate targets for BC.

Methods

The expression of ubiquitin-specific protease 41 (USP41) and its prognosis prediction function was firstly evaluated by TCGA database analysis. Using BC cell lines and specimens from 10 patients with primary BC, the upregulation of USP41 in BC was ensured. By USP41 overexpression or knockdown, its function was studied by cell function assays, small interfering RNA (siRNA), western blot, mass spectrometry, and flow cytometry. The potential mechanism of USP41 was explored via Co-Immunoprecipitation mass spectrometry, and western blot.

Results

TCGA database analysis revealed that in metastatic BC, USP41 expression was upregulated and negatively correlated with BC prognosis. In BC cancer cells and cancer specimens, USP41 was also upregulated. Overexpression of USP41 greatly enhanced BC colony-forming ability, proliferation, and migration. In contrast, USP41 knockdown significantly inhibited BC colony-forming ability, proliferation, and migration. Moreover, Co-Immunoprecipitation mass spectrometry results indicated that USP41 could interact with RACK1. USP41 promoted the protein expression of RACK1. The expression of RACK1 in BC tissues was upregulated. Knockdown of RACK1 inhibited cell growth and migration, and reversed the oncogenic function of USP41 in BC cells.

Conclusions

USP41 can be a potential therapeutic target against BC via RACK1.

miR-20a-5p ameliorates ovalbumin (OVA)-induced mouse model of allergic asthma through targeting ATG7-regulated cell death, fibrosis and inflammation

Autophagy plays an essential role in modulating asthma progression. MiR-20a-5p can regulate autophagy, but its effects on allergic asthma are still unclear. The aim of this study was to explore the potential of miR-20a-5p on autophagy-modulated airway remodeling and to reveal the underlying molecular mechanisms. We found that miR-20a-5p expression was markedly down-regulated in lung of ovalbumin (OVA)-induced mouse model with allergic asthma and in cells stimulated by OVA. Meanwhile, autophagy, apoptosis, fibrosis and inflammatory response were detected in pulmonary tissues from OVA-treated mice. Importantly, luciferase assays showed that ATG7 was a target of miR-20a-5p. We also found that miR-20a-5p over-expression markedly reduced ATG7, while its inhibition promoted ATG7 in cells. In addition, over-expressing miR-20a-5p in OVA-treated cells significantly decreased ATG7 expression levels, along with markedly reduced autophagy, apoptotic cell death, fibrosis and inflammatory response. These results were similar to the effects of autophagy inhibitor 3-Methyladenine (3-MA), indicating that miR-20a-5p was involved in autophagy-induced apoptosis, fibrosis and inflammation. In vivo experiments further demonstrated that miR-20a-5p over-expression was associated with ATG7 reduction in parallel with the alleviated airway remodeling in OVA-treated mice also through suppressing collagen accumulation, apoptosis and inflammation. Similarly, animal studies further confirmed that miR-20a-5p functioned as an autophagy inhibitor to mitigate allergic asthma development. Therefore, miR-20a-5p may be a promising biomarker and therapeutic target during asthma progression by regulating ATG7-modulated autophagy.

GAS5 regulates viability and apoptosis in TGF-β1-stimulated bronchial epithelial cells by regulating miR-217/HDAC4 axis

BACKGROUND

Asthma is a serious respiratory disease that affects the physical and mental health of children. Airway epithelial apoptosis concomitantly mediated by transforming growth factor-β1 (TGF-β1) is a crucial component of asthma pathogenesis. LncRNA growth Arrest Specific 5 (GAS5), microRNA-217 (miR-217) and Histone deacetylase 4 (HDAC4) shown a close relationship with TGF-β1-induced injury of airway epithelial. However, the mechanism underlying TGF-β1-induced injury of airway epithelial in asthma still needs to be investigated.

OBJECTIVE

We aimed to investigate the effect and underlying mechanism of GAS5/miR-217/HDAC4 axis in TGF-β1-stimulated bronchial epithelial cells.

METHODS

The levels of were detected by quantitative real-time polymerase chain reaction (RT-qPCR). All protein levels were determined by western blot. Cell viability and apoptosis rate were assessed by Methyl thiazolyl tetrazolium (MTT) and Flow cytometry, respectively. The targeting relationship between miR-217 and GAS5 or HDAC4 was examined with dual-luciferase reporter assay.

RESULTS

TGF-β1, GAS5, HDAC4 were up-regulated, while miR-217 was down-regulated in bronchial mucosal tissues of asthmatic children and TGF-β1-treated BEAS-2B cells. TGF-β1 could reduce cell viability and induce apoptosis, while these effects could be reversed by downregulation of GAS5 or HDAC4. Mechanically, GAS5 acted as a sponge for miR-217 to regulate the expression of HDAC4. Furthermore, overexpression of HDAC4 rescued the effects of GAS5 knockdown on viability and apoptosis of TGF-β1-induced BEAS-2B cells. GAS5 knockdown induced cell viability and hampered cell apoptosis in TGF-β1-stimulated BEAS-2B cells by regulating the miR-217/HDAC4 axis.

CONCLUSIONS

The lncRNA GAS5/miR-217/HDAC4 axis played an important role in regulating TGF-β1-induced bronchial epithelial cells injury, thus contributing to asthma.

LncRNA OIP5‑AS1 aggravates house dust mite‑induced inflammatory responses in human bronchial epithelial cells via the miR‑143‑3p/HMGB1 axis

Bronchial asthma poses a serious threat to human health. Previous studies have documented the role of long non‑coding RNAs (lncRNAs) in asthma. However, the molecular mechanism underlying bronchial asthma remains unclear. The aim of the present study was to evaluate the role of the lncRNA Opa‑interacting protein 5 antisense RNA1 (OIP5‑AS1) in the house dust mite‑induced inflammatory response in human bronchial epithelial cells. BEAS‑2B cells were treated with Dermatophagoides pteronyssinus peptidase 1 (Der p1) to establish an in vitro model of asthma. OIP5‑AS1 expression levels increased in BEAS‑2B cells following Der p1 treatment, while microRNA (miR)‑143‑3p was downregulated. Additionally, the levels of the pro‑inflammatory factors tumor necrosis factor‑α, interleukin (IL)‑6 and IL‑8 were measured, and apoptosis was evaluated following OIP5 silencing. OIP5‑AS1 knockdown reduced the inflammatory response and apoptosis in BEAS‑2B cells. Furthermore, using dual luciferase reporter assays and co‑transfection experiments, it was demonstrated that the function of OIP5‑AS1 was mediated by miR‑143‑3p. miR‑143‑3p overexpression attenuated the Der p1‑induced inflammatory response and apoptosis of BEAS‑2B cells by targeting high mobility group box 1 (HMGB1). In summary, OIP5‑AS1 exacerbated Der p1‑induced inflammation and apoptosis in BEAS‑2B cells by targeting miR‑143‑3p via HMGB1.

Redox-Sensitive Glyoxalase 1 Up-Regulation Is Crucial for Protecting Human Lung Cells from Gold Nanoparticles Toxicity

Gold nanoparticles (AuNPs) are considered nontoxic upon acute exposure, at least when they are equal or above 5 nm size. However, the safeguard mechanisms contributing to maintain cell viability are scarcely explored so far. Here, we investigated the cyto-protective role of Glyoxalase 1 (Glo1), a key enzyme involved in the control of deleterious dicarbonyl stress, in two human cell types of the respiratory tract, after an acute exposure to AuNPs with a main size of 5 nm. We found that the redox sensitive Nrf-2-mediated up-regulation of Glo1 was crucial to protect cells from AuNPs-induced toxicity. However, cells challenged with a pro-inflammatory/pro-oxidative insult become susceptible to the pro-apoptotic effect of AuNPs. Notably, the surviving cells undergo epigenetic changes associated with the onset of a partial epithelial to mesenchymal transition (EMT) process (metastable phenotype), driven by the increase in dicarbonyl stress, consequent to Glo1 inactivation. As a physiological respiratory epithelium is required for the normal respiratory function, the knowledge of the protective mechanisms avoiding or (when challenged) promoting its modification/damage might provide insight into the genesis, and, most importantly, prevention of potential health effects that might occur in subjects exposed to AuNPs, through targeted surveillance programs, at least under specific influencing factors.

Dabigatran ameliorates airway smooth muscle remodeling in asthma by modulating Yes-associated protein

Accumulating evidence indicates that thrombin, the major effector of the coagulation cascade, plays an important role in the pathogenesis of asthma. Interestingly, dabigatran, a drug used in clinical anticoagulation, directly inhibits thrombin activity. The aim of this study was to investigate the effects and mechanisms of dabigatran on airway smooth muscle remodeling in vivo and in vitro. Here, we found that dabigatran attenuated inflammatory pathology, mucus production, and collagen deposition in the lungs of asthmatic mice. Additionally, dabigatran suppressed Yes‐associated protein (YAP) activation in airway smooth muscle of asthmatic mice. In human airway smooth muscle cells (HASMCs), dabigatran not only alleviated thrombin‐induced proliferation, migration and up‐regulation of collagen I, α‐SMA, CTGF and cyclin D1, but also inhibited thrombin‐induced YAP activation, while YAP activation mediated thrombin‐induced HASMCs remodeling. Mechanistically, thrombin promoted actin stress fibre polymerization through the PAR1/RhoA/ROCK/MLC2 axis to activate YAP and then interacted with SMAD2 in the nucleus to induce downstream target genes, ultimately aggravating HASMCs remodeling. Our study provides experimental evidence that dabigatran ameliorates airway smooth muscle remodeling in asthma by inhibiting YAP signalling, and dabigatran may have therapeutic potential for the treatment of asthma.

Dual role of RACK1 in airway epithelial mesenchymal transition and apoptosis

Airway epithelial apoptosis and epithelial mesenchymal transition (EMT) are two crucial components of asthma pathogenesis, concomitantly mediated by TGF‐β1. RACK1 is the downstream target gene of TGF‐β1 shown to enhancement in asthma mice in our previous study. Balb/c mice were sensitized twice and challenged with OVA every day for 7 days. Transformed human bronchial epithelial cells, BEAS‐2B cells were cultured and exposed to recombinant soluble human TGF‐β1 to induced apoptosis (30 ng/mL, 72 hours) and EMT (10 ng/mL, 48 hours) in vitro, respectively. siRNA and pharmacological inhibitors were used to evaluate the regulation of RACK1 protein in apoptosis and EMT. Western blotting analysis and immunostaining were used to detect the protein expressions in vivo and in vitro. Our data showed that RACK1 protein levels were significantly increased in OVA‐challenged mice, as well as TGF‐β1‐induced apoptosis and EMT of BEAS‐2B cells. Knockdown of RACK1 (siRACK1) significantly inhibited apoptosis and decreased TGF‐β1 up‐regulated EMT related protein levels (N‐cadherin and Snail) in vitro via suppression of JNK and Smad3 activation. Moreover, siSmad3 or siJNK impaired TGF‐β1‐induced N‐cadherin and Snail up‐regulation in vitro. Importantly, JNK gene silencing (siERK) also impaired the regulatory effect of TGF‐β1 on Smad3 activation. Our present data demonstrate that RACK1 is a concomitant regulator of TGF‐β1 induces airway apoptosis and EMT via JNK/Smad/Snail signalling axis. Our findings may provide a new insight into understanding the regulation mechanism of RACK1 in asthma pathogenesis.