BACKGROUND:Hypoxic pulmonary hypertension (HPH) is a representative vascular remodeling disease with a poor prognosis. Previous findings from our study have implicated the NICD4 (Notch4 intracellular domain) in pulmonary artery smooth muscle cells (PASMCs) in the pathogenesis of HPH. However, the underlying regulatory mechanisms remain unclear. In this study, we aimed to elucidate the potential regulatory mechanism of NICD4 in HPH. METHODS:Using coimmunoprecipitation combined with mass spectrometry, we identified USP8 (ubiquitin-specific peptidase 8) as a novel binding protein of NICD4 in PASMCs. The functional role of USP8 was investigated in vivo using smooth muscle cell-specific Usp8 knockout (Usp8Acta2-/-) mice and in vitro using primarily cultured PASMCs, alongside pharmacological inhibition with DUB-IN-2 (deubiquitinase-inhibitor-2). RESULTS:USP8 was significantly upregulated in lung tissues from patients with HPH due to interstitial lung disease or chronic obstructive pulmonary disease, HPH rodent models, as well as in hypoxic PASMCs. Usp8 deficiency in Acta2-positive mice (Usp8Acta2-/-) or pharmacological inhibition of USP8 by DUB-IN-2 markedly attenuated HPH development. In vitro, USP8 knockdown suppressed hypoxia-induced PASMC proliferation, migration, and apoptosis resistance by modulating the NICD4-MAPK pathway. Mechanistically, USP8 was bound directly to NICD4 to maintain its stability by removing the K48-linked ubiquitin chain on NICD4 at lysine 1760, thus preventing proteasomal degradation. Furthermore, USP8 can be transcriptionally upregulated by CSL/NICD4 under hypoxia, forming a NICD4/USP8-positive feedback loop. CONCLUSIONS:Our study unveils a critical NICD4/USP8-positive feedback loop that drives HPH pathogenesis, highlighting the importance of ubiquitination in pulmonary vascular remodeling. Targeted disruption of this loop represents a promising therapeutic strategy for HPH.

This study investigates the therapeutic potential of bone marrow macrophages-derived dendritic cells (BMΦDCs) in enhancing antitumor immunity against head and neck squamous cell carcinoma (HNSCC), focusing on their effects in inhibiting tumor growth, reducing metastasis, and modulating the tumor microenvironment. BMΦDCs were generated by culturing bone marrow cells with macrophage colony-stimulating factor (M-CSF) followed by granulocyte–macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). MTCQ-1 tumor lysates were used for antigen loading. The phenotypic characteristics of BMΦDCs were analyzed using flow cytometry. In vivo antitumor efficacy was assessed in subcutaneous and lung metastasis models in immunocompetent C57BL/6 mice. Tumor growth was monitored, and tumor tissues were collected for histological analysis using hematoxylin and eosin (H E), Masson’s trichrome, and anti-CD8 staining. BMΦDCs displayed higher maturation marker expression (CD40, CD86) compared to traditional BMDCs. In the subcutaneous tumor model, BMΦDCs significantly inhibited tumor growth and enhanced cytotoxic T lymphocyte (CTL) activity. In the lung metastasis model, BMΦDCs effectively reduced metastatic burden. Histological analysis revealed increased CD8+ T cell infiltration and reduced tumor fibrosis in BMΦDC-treated mice. No significant toxicity or organ damage was observed. BMΦDCs are a promising immunotherapeutic approach for HNSCC, demonstrating superior antitumor efficacy, enhanced immune responses, and excellent biosafety. These findings highlight the potential of BMΦDCs in advancing cancer immunotherapy.

Background Hypoxia-induced pulmonary hypertension (HPH) is a cardiopulmonary disease marked by pulmonary vascular remodeling and elevated resistance in the pulmonary arteries. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is a key mediator in the pathophysiology of multiple diseases, yet its functional involvement in HPH remains poorly understood. Methods We first examined TRAF6 expression and localization in lung tissues from HPH patients and experimental mouse models using Western blotting and immunofluorescence. Adeno-associated virus 9 (AAV9) with the SM22α promoter was used to achieve spatially restricted silencing of TRAF6 in vascular smooth muscle cells in vivo. Subsequently, hypoxic human pulmonary arterial smooth muscle cells (HPASMCs) were subjected in vitro to EdU proliferation assays, Transwell migration assays, Annexin V-FITC/PI apoptosis detection, electron microscopy, immunofluorescence, flow cytometry, qPCR, and Western blotting to evaluate TRAF6’s effects on phenotypic modulation and mitophagy. Results TRAF6 was significantly overexpressed in both human HPH tissues and experimental HPH mouse models. Inhibition of TRAF6 attenuated hypoxia-induced phenotypic switching of HPASMCs in vitro, while in vivo TRAF6 silencing ameliorated pulmonary vascular remodeling and right ventricular hypertrophy. Mechanistically, TRAF6 knockdown suppressed mitochondrial dysfunction and excessive mitophagy in HPASMCs under hypoxia. Notably, hypoxia upregulated TRAF6 expression in the endoplasmic reticulum (ER), where it selectively activated the IRE1/XBP1 signaling axis during ER stress. Crucially, inhibition of the IRE1α/XBP1s pathway partially reversed TRAF6-mediated regulation of mitophagy, proliferation, migration, and apoptosis resistance in HPASMCs. Conclusions Our findings demonstrate that TRAF6 exacerbates endoplasmic reticulum stress and dysregulates mitophagy, thereby driving pathological HPASMC proliferation and migration during HPH progression. TRAF6 inhibition presents a potential therapeutic intervention against the pathological vascular remodeling in HPH.

Lung cancer is one of the leading causes of cancer-related mortality, and liquid biopsy, particularly the detection of circulating tumor DNA (ctDNA), offers a promising non-invasive alternative for diagnosis. Despite significant research on ctDNA in lung cancer, a comprehensive bibliometric analysis on this topic is lacking in the literature. This study systematically reviews ctDNA research trends in lung cancer using bibliometric methods to identify leading contributors, emerging themes, and underexplored areas for future research. We conducted a search of the Web of Science Core Collection database for ctDNA-related lung cancer publications up to 2023. The bibliometric analysis was performed using VOSviewers, CiteSpace, and the R package “bibliometrix.” The results revealed a total of 2862 publications on ctDNA in lung cancer, comprising 1998 articles and 864 reviews. Between 2021 and 2023, the number of publications stabilized, with an average of approximately 360 publications per year. The countries with the highest number of published papers were China and the United States. The University of Texas MD Anderson Cancer Center was the leading institution in terms of publication output. Among journals, Cancers published the highest number of papers, while Clinical Cancer Research had the highest citation impact. Lanman RB was the leading author by publication count, and Newman was the most co-cited author. Current research on ctDNA in lung cancer primarily focuses on areas such as minimal residual disease, prognosis and recurrence monitoring, adjuvant therapy decision-making, epidermal growth factor receptor and targeted therapy, and immunotherapy. This bibliometric analysis highlights the impact of ctDNA in lung cancer, revealing key contributors and emerging research trends.

BackgroundChronic obstructive pulmonary disease (COPD) is one of the most prevalent chronic respiratory diseases and the fourth cause of mortality globally. Neutrophilic inflammation has a vital role in the occurrence and progression of COPD. This study aimed to identify the novel hub genes involved in neutrophilic inflammation in COPD through bioinformatic prediction and experimental validation.MethodsBoth the single-cell RNA sequencing (scRNA-seq) dataset (GSE173896) and the RNA sequencing (RNA-seq) dataset (GSE57148) were downloaded from the Gene Expression Omnibus (GEO) database. The Seurat package was used for quality control, dimensions reduction, and cell identification of scRNA-seq. The irGSEA package was used for scoring individual cells. The Monocle2 package was used for the trajectory analysis of neutrophils. The CIBERSORT algorithm was used for analysis of immune cell infiltration in the lungs of COPD patients and controls in RNA-seq dataset, and weighted gene co-expression network analysis (WGCNA) correlated gene modules with neutrophil infiltration. The Mendelian randomization (MR) analysis explored the causal relationship between feature DEGs and COPD. The protein–protein interaction (PPI) network of novel hub genes was constructed, and real-time quantitative polymerase chain reaction (qRT-PCR) was used to validate novel hub genes in clinical specimens.ResultsIn scRNA-seq, the gene sets upregulated in COPD samples were related to the neutrophilic inflammatory response and TNF-α activation of the NF-κB signaling pathway. In RNA-seq, immune infiltration analysis showed neutrophils were upregulated in COPD lung tissue. We combined data from differential and modular genes and identified 51 differential genes associated with neutrophilic inflammation. Using MR analysis, 6 genes were explored to be causally associated with COPD. Meanwhile, 11 hub genes were identified by PPI network analysis, and all of them were upregulated. qRT-PCR experiments validated 9 out of 11 genes in peripheral blood leukocytes of COPD patients. Furthermore, 5 genes negatively correlated with lung function in COPD patients. Finally, a network of transcription factors for NAMPT and PTGS2 was constructed.ConclusionThis study identified nine novel hub genes related to the neutrophilic inflammation in COPD, and two genes were risk factors of COPD, which may serve as potential biomarkers for the clinical severity of COPD.

BackgroundAsthma is a chronic respiratory disease and is often associated with multiple comorbidities. The causal relationship between asthma and these comorbidities is still unclear. This study aimed to investigate the association between genetically predicted asthma and common comorbidities.MethodsAfter searching PubMed and GWAS summary statistics, we identified 26 comorbidities of asthma. The causal relationship between asthma and comorbidities was assessed in two independent GWASs by bidirectional Mendelian randomization, followed by validation of the results using a multivariate Mendelian randomization analysis and several sensitivity analyses.ResultsIn the bidirectional Mendelian randomization analysis, chronic sinusitis [odds ratio (OR) = 1.54, p = 1.40 × 10−5], atopic dermatitis (OR = 1.36, p = 9.37 × 10−21), allergic conjunctivitis (OR = 2.07, p = 4.32 × 10−6), and allergic rhinitis (OR = 1.53, p = 5.20 × 10−6) were significantly associated with increased asthma risk. Hyperthyroidism (OR = 1.12, p = 0.04) had a potential increased risk for asthma. For the reverse direction, asthma showed significant associations with an increased risk of chronic obstructive pulmonary disease (OR = 1.24, p = 2.25 × 10−9), chronic sinusitis (OR = 1.61, p = 5.25 × 10−21), atopic dermatitis (OR = 2.11, p = 1.24 × 10−24), allergic conjunctivitis (OR = 1.65, p = 6.66 × 10−35), allergic rhinitis (OR = 1.90, p = 2.38 × 10−57), and a potential higher risk of allergic urticaria (OR = 1.25, p = 0.003).ConclusionThis study suggested a significant bidirectional association of chronic sinusitis, atopic dermatitis, allergic conjunctivitis, and allergic rhinitis with asthma. In addition, hyperthyroidism was associated with an increased risk of asthma and asthma increased the risk of chronic obstructive pulmonary disease and allergic urticaria.

BACKGROUND:Asthma imposes a large healthcare burden in China and the United States (US). However, the trends of asthma mortality and the relative risk factors have not been comparatively analyzed between the countries. The aim of this study was to compare the mortality and risk factors between China and the US. METHODS:The deaths, and mortality rates of asthma in China and the US during 1990-2019 were obtained from the Global Burden of Disease Study 2019. The age-period-cohort model was used to estimate these mortality rates based on a log-linear scale with additive age, period, and cohort effects. The population attributable fractions of risk factors for asthma were estimated. RESULTS:In 1990-2019, the asthma mortality rate was higher in China than in the US. The crude and age-standardized asthma mortality rates trended downward in both China and the US from 1990 to 2019. The decline in mortality was more obvious in China. Mortality gap between the two countries was narrowing. A sex difference in asthma mortality was observed with higher mortality in males in China and females in the US. The age effects showed that mortality increased with age in adults older than 20 years, particularly in the elderly. Downward trends were generally observed in the period and cohort rate ratios in both countries, with China experiencing a more obvious decrease. Smoking and high body mass index (BMI) were the leading risk factors for asthma mortality in China and the US, respectively. Mortality attributable to occupational asthmagens and smoking decreased the most in China and the US, respectively. CONCLUSIONS:In 1990-2019, the asthma mortality rate was higher in China than in the US; however, the mortality gap has narrowed. Mortality increased with age in adults. The improvements in asthma death risk with period and birth cohort were more obvious in China than in the US. Smoking, high BMI, and aging are major health problems associated with asthma control. The role of occupational asthmagens in asthma mortality underscores the importance of management and prevention of occupational asthma.

Notch signaling is involved in cell fate determination and deregulated in human solid tumors. Hypoxia is an important feature in many solid tumors, which activates hypoxia-induced factors (HIFs) and their downstream targets to promote tumorigenesis and cancer development. Recently, HIFs have been shown to trigger the Notch signaling pathway in a variety of organisms and tissues. In this review, we focus on the pro- and anti-tumorigenic functions of Notch signaling and discuss the crosstalk between Notch signaling and cellular hypoxic response in cancer pathogenesis, including epithelia-mesenchymal transition, angiogenesis, and the maintenance of cancer stem cells. The pharmacological strategies targeting Notch signaling and hypoxia in cancer are also discussed in this review.

Exosomes are small extracellular vesicles that are secreted by almost all types of cells and exist in almost all extracellular spaces. As an important mediator of intercellular communication, exosomes encapsulate the miRNA, lncRNA, cirRNA, mRNA, cytokine, enzyme, lipid, and other components from the cytoplasm into its closed single membrane structure and transfer them to recipient units in an autocrine, paracrine, or endocrine manner. Hypoxia is a state of low oxygen tension and is involved in many pathological processes. Hypoxia influences the size, quantity, and expression of exosome cargos. Exosomes derived from hypoxic tumor cells transfer genetics, proteins, and lipids to the recipient units to exert pleiotropic effects. Different donor cells produce different cargo contents, target different recipient units and lead to different biological effects. Hypoxic exosomes derived from tumor cells uptaken by normoxic tumor cells lead to promoted proliferation, migration, and invasion; uptaken by extracellular space or liver lead to promoted metastasis; uptaken by endothelial cells lead to promoted angiogenesis; uptaken by immune cells lead to promoted macrophage polarization and changed tumor immune microenvironment. In addition to various types of tumors, hypoxic exosomes also participate in the development of diseases in the cardiovascular system, neuron system, respiratory system, hematology system, endocrine system, urinary system, reproduction system, and skeletomuscular system. Understanding the special characteristics of hypoxic exosomes provide new insight into elaborating the pathogenesis of hypoxia related disease. This review summarizes hypoxia induced cargo changes and the biological effects of hypoxic exosomes in tumors and non-malignant diseases in different systems.

Hypoxic pulmonary hypertension (HPH) is characterized by elevated pulmonary artery resistance and vascular remodeling. Endoplasmic reticulum stress (ERS) is reported to be involved in HPH, but the underlying mechanisms remain uncertain. We found that Xbp1s, a potent transcription factor during ERS, was elevated in hypoxic-cultured rat PASMCs and lung tissues from HPH rats. Our in vitro experiments demonstrated that overexpressing Xbp1s can promote proliferation, cell viability, and migration and inhibit the apoptosis of PASMCs, while silencing Xbp1s led to the opposite. Through data-independent acquisition (DIA) mass spectrometry, we identified extensive proteomic alterations regulated by hypoxia and Xbp1s. Further validation revealed that p-JNK, rather than p-ERK or p-p38, was the downstream effector of Xbp1s. p-JNK inhibition reversed the biological effects of Xbp1s overexpression in vitro. In the animal HPH model, rats were randomly assigned to five groups: normoxia, hypoxia, hypoxia+AAV-CTL (control), hypoxia+AAV-Xbp1s (prevention), and hypoxia+AAV-Xbp1s (therapy). Adeno-associated virus (AAV) serotype 1-mediated Xbp1s knockdown in the prevention and therapy groups significantly reduced right ventricular systolic pressure, total pulmonary resistance, right ventricular hypertrophy, and the medial wall thickness of muscularized distal pulmonary arterioles; AAV-Xbp1s also decreased proliferating cell nuclear antigen expression and increased apoptosis in pulmonary arterioles. Collectively, our findings demonstrated that the Xbp1s-p-JNK pathway is important in hypoxic vascular remodeling and that targeting this pathway could be an effective strategy to prevent and alleviate HPH development.

Spliced X-box binding protein 1 (XBP1s) has been reported to participate in the pathogenesis of numerous types of cancer; however, whether XBP1s plays a role in lung cancer remains to be elucidated. In the present study, bioinformatics analysis was performed to determine the mRNA expression level of XBP1 in lung cancer and adjacent normal tissues. Gene Ontology terms, pathway enrichment and Pearson's correlation analysis were performed to investigate the possible mechanism involved. Western blot and reverse transcription-quantitative PCR were performed to quantify the protein and mRNA expression level of target proteins, respectively. Small interfering RNA or overexpression plasmid were used to knockdown or overexpress the expression level of XBP1s. EdU staining, colony formation, Cell Counting Kit-8, Transwell and wound healing assays, and flow cytometry were performed to detect the proliferation, colony forming ability, cell viability, migration and invasion ability, and the apoptosis rate. The results showed that the mRNA and protein expression level of XBP1 was higher in tumor tissues compared with that in adjacent normal tissues using data from the TIMER2.0, ONCOMINE and UALCAN online databases. In addition, the mRNA expression level of XBP1 was also associated with clinical features, including age, smoking habit, individual cancer stage and nodal metastasis status. In the in vitro experiments, the mRNA and protein expression level of XBP1s was increased in the A549 cell line compared with that in the human bronchial epithelial (HBE), H1299, PC9 and H460 cell lines. Hypoxia further increased the protein expression level of XBP1s in the A549 cell line. Knockdown of XBP1s expression in the A549 cell line resulted in decreased proliferation, colony formation, cell viability, migration and invasion, and increased apoptosis. By contrast, overexpressing XBP1s in the HBE cell line led to the opposite results. To investigate the mechanism involved, proteins associated with XBP1 were analyzed using the LinkedOmics database. Pathway enrichment revealed the MAPK pathway to be the possible XBP1 downstream target. Furthermore, Pearson's correlation and western blot analyses verified that phosphorylated (p)-JNK rather than p-ERK or p-p38 was the downstream effector of XBP1s. Phosphorylation of JNK was decreased when XBP1s expression was knocked down in the A549 cell line under normoxic and hypoxic conditions. Inhibiting p-JNK with SP600125 reversed the increased prosurvival effects caused by XBP1s overexpression. The results from the present study suggest that XBP1s/p-JNK function as a prosurvival factors in the A549 cell line and could be a potential target for the treatment of lung adenocarcinoma.

AIM:To investigate the preparation, physicochemical characterization and cytotoxicity in vitro of Gemcitabine-loaded poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-PDLLA) nanovesicles. METHODS:The nanovesicle carriers were prepared from the amphiphilic block copolymer of PEG-PDLLA by a double emulsion technique, and gemcitabine was used as the model drug. The morphology of the nanovesicles was determined by scanning and transmission electron microscopy, and the drug content, drug entrapment and drug-release curve in vitro were detected by UV-Vis-NIR spectrophotometry. Cytotoxicity in the human pancreatic cancer cell line SW1990 was tested by 3-(4,5-dimethyl) ethiazole (MTT) assay. RESULTS:The gemcitabine-loaded nanovesicles were hollow nanospheres with a mean size of 200.6 nm, drug loading of 4.14% and drug embedding ratio of 20.54%. The nanovesicles showed excellent controlled release that was characterized by a fast initial release during the first 72 h, followed by a slower and continuous release. The MTT assay demonstrated that gemcitabine-loaded nanovesicles exhibited dose-dependent and time-delayed cytotoxicity in the human pancreatic cancer cell line SW1990. CONCLUSION:Gemcitabine-loaded PEG-PDLLA nanovesicles prepared by a double emulsion technique exhibited good performance for controlled drug release, and had similar cytotoxic activity to free gemcitabine.

Background: The super-spreading events were associated with the outbreaks of SARS and MERS, but their association with the outbreak of COVID-19 was unknown before we first published a report in medRxiv preprint in March 2020. Here, we reported a super-spreading transmission chain of SARS-CoV-2 involving an index patient, seven cancer patients, 40 health care workers and four family members. Methods: We conducted a retrospective study to identify the index patient and the exposed individuals linked to a chain of transmission associated with COVID-19. We collected and analyzed the data on demographic features, exposure history, clinical presentation, laboratory investigation, radiological examination, and disease outcome of these patients. Results: We identified the index patient and another presumptive “super-spreader”, who initiated and amplified a super-spreading transmission chain associated with COVID-19, respectively. There were 31 female and 21 male patients in this cohort, and the median age was 37 years (range: 22-79 years). Each of them had an exposure history with the index patient or his close contacts. Approximately 87% (45/52) of the patients had fever or other symptoms, 96% (50/52) had abnormal chest CT-scan findings, 86% of the tested patients (39/45) were positive for SARS-CoV-2 in the nasopharyngeal or throat swab specimen, 85% of the tested patients (29/34) were positive for SARS-CoV-2-specific IgM and/or IgG, 15% of the RT-PCR positive patients were tested negative for the specific IgM and/or IgG at the convalescent phase, and 15% of the RT-PCR negative patients were tested positive for the specific IgM and/or IgG. The severe patients experienced a significant decrease in oximetry saturation, lymphocyte, and platelet counts, along with a significant increase in C-reactive protein, D-dimer, and lactate dehydrogenase. All six fatal cases had comorbidities and five of the seven cancer patients (71%) died within 2-20 days of the disease onset. Conclusions: Our findings suggested that the super-spreading events associated with COVID-19 took place at the early stage of the disease outbreak in Wuhan. The cancer patients appeared to be highly vulnerable to SASR-CoV-2 infection.

Irreversible pulmonary hypertension (PH) mainly results from vascular remodeling, in which the aberrant growth of pulmonary arterial smooth muscle cells (PASMCs) plays a significant role. Our previous work suggested that KLF5 and HIF1α are closely associated with the pathogenesis of hypoxic PH as they intervene in the growth of PASMCs. MicroRNAs (miRNAs) have been demonstrated to be involved in the control of cell proliferation and apoptosis. In the present study, we detected the expression of six miRNAs connected with KLF5 in hypoxia-exposed rat PH models and PASMCs and then further investigated the role of miR-320-3p in the abnormal proliferation of hypoxic PASMCs and in the progression and treatment outcomes of hypoxia-induced PH. The results indicated that miR-320-3p was downregulated in hypoxia-exposed rat PH models, hypoxia-induced PASMCs and chronic thromboembolic pulmonary hypertension (CTEPH) patients. Moreover, miR-320-3p directly regulated the expression of KLF5 and HIF1α. miR-320-3p mimics inhibited proliferation and migration and promoted apoptosis in hypoxic PASMCs. KLF5 and HIF1α reversed the above effects of miR-320-3p. In conclusion, miR-320-3p plays a certain role in the progression of hypoxic PH via KLF5 and HIF1α and might be a potent therapeutic tool for PH.

Pulmonary hypertension (PH) is a life-threatening disease characterized by vascular remodeling. Exploring new therapy target is urgent. The purpose of the present study is to investigate whether and how spliced x-box binding protein 1 (xbp1s), a key component of endoplasmic reticulum stress (ERS), contributes to the pathogenesis of PH. Forty male SD rats were randomly assigned to four groups: Control, Monocrotaline (MCT), MCT+AAV-CTL (control), and MCT+AAV-xbp1s. The xbp1s protein levels were found to be elevated in lung tissues of the MCT group. Intratracheal injection of adeno-associated virus serotype 1 carrying xbp1s shRNA (AAV-xbp1s) to knock down the expression of xbp1s effectively ameliorated the MCT-induced elevation of right ventricular systolic pressure (RVSP), total pulmonary resistance (TPR), right ventricular hypertrophy and medial wall thickness of muscularized distal pulmonary arterioles. The abnormally increased positive staining rates of proliferating cell nuclear antigen (PCNA) and Ki67 and decreased positive staining rates of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) in pulmonary arterioles were also reversed in the MCT+AAV-xbp1s group. For mechanistic exploration, bioinformatics prediction of the protein network was performed on the STRING database, and further verification was performed by qRT-PCR, Western blots and co-immunoprecipitation (Co-IP). DNA damage-inducible transcript 3 (Ddit3) was identified as a downstream protein that interacted with xbp1s. Overexpression of Ddit3 restored the decreased proliferation, migration and cell viability caused by silencing of xbp1s. The protein level of Ddit3 was also highly consistent with xbp1s in the animal model. Taken together, our study demonstrated that xbp1s-Ddit3 may be a potential target to interfere with vascular remodeling in PH.

Hypoxic pulmonary hypertension (PH) is a refractory pulmonary vascular remodeling disease, and the efficiency of current PH treatment strategies is unsatisfactory. Tribbles homolog 3 (TRB3), a member of the pseudokinase family, is upregulated in diverse types of cellular stresses and functions as either a pro-proliferative or pro-apoptotic factor depending on the specific microenvironment. The regulatory mechanisms of TRB3 in hypoxic PH are poorly understood. We performed studies using TRB3-specific silencing and overexpressing lentiviral vectors to investigate the potential roles of TRB3 on hypoxic pulmonary artery smooth muscle cells (PASMCs). Adeno-associated virus type 1(AVV1) vectors encoding short-hairpin RNAs against rat TRB3 were used to assess the role of TRB3 on hypoxic PH. TRB3 protein expression in PH patients was explored in clinical samples by western blot analysis. The results of whole-rat genome oligo microarrays showed that the expression of TRB3 and endoplasmic reticulum stress (ERS)-related genes was upregulated in hypoxic PASMCs. TRB3 protein expression was significantly upregulated by hypoxia and thapsigargin. In addition, 4-PBA and 4μ8C, both inhibitors of ERS, decreased the expression of TRB3. TRB3 knockdown promoted apoptosis and damaged the proliferative and migratory abilities of hypoxic PASMCs as well as inhibited activation of the MAPK signaling pathway. TRB3 overexpression stimulated the proliferation and migration of PASMCs but decreased the apoptosis of PASMCs, which was partly reversed by specific inhibitors of ERK, JNK and p38 MAPK. The Co-IP results revealed that TRB3 directly interacts with ERK, JNK, and p38 MAPK. Knockdown of TRB3 in rat lung tissue reduced the right ventricular systolic pressure and decreased pulmonary medial wall thickness in hypoxic PH model rats. Further, the expression of TRB3 in lung tissues was higher in patients with PH compared with those who have normal pulmonary artery pressure. TRB3 was upregulated in hypoxic PASMCs and was affected by ERS. TRB3 plays a key role in the pathogenesis of hypoxia-induced PH by binding and activating the ERK, JNK, and p38 MAPK pathways. Thus, TRB3 might be a promising target for the treatment of hypoxic PH.

Hypoxia contributes to the progression and metastasis of lung adenocarcinoma (LUAD). However, the specific underlying molecular mechanisms have not been fully elucidated. Here we report that Notch4 is upregulated in lung tissue from lung cancer patients. Functionally, Hypoxia activates the expressions of Delta-like 4 and Notch4, resulting in the excessive proliferation and migration of LUAD cells as well as apoptotic resistance. Notch4 silencing reduced ERK, JNK, and P38 activation. Meanwhile, Notch4 overexpression enhanced ERK, JNK, and P38 activation in LUAD cells. Furthermore, Notch4 exerted pro-proliferation, anti-apoptosis and pro-migration effects on LUAD cells that were partly reversed by the inhibitors of ERK, JNK, and p38. The binding interaction between Notch4 and ERK/JNK/P38 were confirmed by the co-immunoprecipitation assay. In vivo study revealed that Notch4 played a key role in the growth and metastasis of LUAD using two xenograft models. This study demonstrates that hypoxia activates Notch4-ERK/JNK/P38 MAPK signaling pathways to promote LUAD cell progression and metastasis.