Salmonella spvC gene suppresses macrophage/neutrophil antibacterial defense mediated by gasdermin D.

OBJECTIVE: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a representative model organism for investigating host-pathogen interactions. It was reported that S. Typhimurium spvC gene alleviated intestinal inflammation to aggravate systemic infection, while the precise mechanisms remain unclear. In this study, the influence of spvC on the antibacterial defense of macrophage/neutrophil mediated by gasdermin D (GSDMD) was investigated. METHODS: Mouse macrophage-like cell lines J774A.1 and RAW264.7, neutrophil-like cells derived from HL-60 cells (human promyletic leukemia cell lines) were infected with S. Typhimurium wild type, spvC deletion and complemented strains. Cell death was evaluated by LDH release and Annexin V-FITC/PI staining. Macrophage pyroptosis and neutrophil NETosis were detected by western blotting, live cell imaging and ELISA. Flow cytometry was used to assess the impact of spvC on macrophage-neutrophil cooperation in macrophage (dTHP-1)-neutrophil (dHL-60) co-culture model pretreated with GSDMD inhibitor disulfiram. Wild-type and Gsdmd-/- C57BL/6J mice were utilized for in vivo assay. The degree of phagocytes infiltration and inflammation were analyzed by immunofluorescence and transmission electron microscopy. RESULTS: Here we find that spvC inhibits pyroptosis in macrophages via Caspase-1/Caspase-11 dependent canonical and non-canonical pathways, and restrains neutrophil extracellular traps extrusion in GSDMD-dependent manner. Moreover, spvC could ameliorate macrophages/neutrophils infiltration and cooperation in the inflammatory response mediated by GSDMD to combat Salmonella infection. CONCLUSIONS: Our findings highlight the antibacterial activity of GSDMD in phagocytes and reveal a novel pathogenic mechanism employed by spvC to counteract this host defense, which may shed new light on designing effective therapeutics to control S. Typhimurium infection.

Aconitum coreanum and processed products on its base prevent stroke via the PI3K/Akt and KEAP1/NRF2 in the in vivo study.

Aconitum coreanum (A. coreanum), a traditional Chinese medicine, has been proved to treat ischemic stroke (IS). However, the mechanisms of A. coreanum's anti-stroke is currently unknown. This study aimed to uncover the effect and mechanisms of A. coreanum. And study raw Aconitum coreanum (RA) and steamed Aconitum coreanum (SA) and Aconitum coreanum processed with ginger and Alumen (GA) on the mechanism of the pharmacological action of treating IS. Determining whether the efficacy is affected after processing. The right unilateral ligation of the carotid artery of gerbils was used to mimic IS. The neurological function score, infarct volume, oxidative stress level and inflammatory factor expression were measured in gerbils after IS. Western blot and immunofluorescence analyses were conducted to evaluate the expression of related proteins. Metabolomic analyzes IS-related metabolic pathways in urinary metabolites. RA, SA and GA significantly improved the infarct volume and behavioral score of IS gerbils, increased the expression of brain tissue superoxide dismutase (SOD), glutathione (GSH), nitric oxide (NO) and decreased the content of malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α). Western blot and immunofluorescence analysis results showed that RA, SA and GA significantly increased the expression of P-Akt, PI3K, HO-1 and KEAP1. Metabolomic studies identified 112 differential metabolites, including L-Proline, Riboflavin, Leukotriene D4, and 7-Methylxanthine, as potential biomarkers of stroke, involving 14 metabolic pathways including riboflavin metabolism, pyrimidine metabolism, and purine metabolism. Our findings indicated that A. coreanum protected against cerebral ischemia injury probably via the PI3K/Akt and KEAP1/NRF2 pathway. A. coreanum before and after processing both had a protective effect against IS brain injury in gerbils. The A. coreanum efficacy was not reduced after processing. Even compared to RA, SA had better efficacy.

Role of formyl peptide receptor 2 in steatosis of L02 cells exposed to Mono-(2-ethylhexyl) phthalate.

Mono-(2-ethylhexyl) phthalate (MEHP) can accumulate in the liver and then lead to hepatic steatosis, while the underlying mechanism remains unclear. Inflammation plays an important role in the disorder of hepatic lipid metabolism. This study aims to clarify the role of the inflammatory response mediated by formyl peptide receptor 2 (FPR2) in steatosis of L02 cells exposed to MEHP. L02 cells were exposed to MEHP of different concentrations and different time. A steatosis model of L02 cells was induced with oleic acid and the cells were exposed to MEHP simultaneously. In addition, L02 cells were incubated with FPR2 antagonist and then exposed to MEHP. Lipid accumulation was determined by oil red O staining and extraction assay. The indicators related to lipid metabolism and inflammatory response were measured with appropriate kits. The relative expression levels of FPR2 and its ligand were determined by Western blot, and the interaction of them was detected by co-immunoprecipitation. As a result, MEHP exposure could promote the occurrence and progression of steatosis and the secretion of chemokines and inflammatory factors in L02 cells. MEHP could also affect the expression and activation of FPR2 and the secretion of FPR2 ligands. In addition, the promotion effect of MEHP on the secretion of total cholesterol and interleukin 1ß in L02 cells could be significantly inhibited by the FPR2 antagonist. We concluded that FPR2 might affect the promotion effect of MEHP on steatosis of L02 cells by mediating inflammatory response.

miR-132-3p promotes heat stimulation-induced esophageal squamous cell carcinoma tumorigenesis by targeting KCNK2.

Epidemiological evidence supports that consumption of high-temperature food and beverages is an important risk factor for esophageal squamous cell carcinoma (ESCC); however, the underlying mechanism still remains unclear. Here, we established a series of animal models and found that drinking 65°C water can promote esophageal tumor progression from preneoplastic lesions to ESCC. RNA sequencing data showed that miR-132-3p was highly expressed in the heat stimulation group compared with controls. Further study verified that miR-132-3p were upregulated in human premalignant lesion tissues of the esophagus, ESCC tissues, and cells. Overexpression of miR-132-3p could promote ESCC cell proliferation and colony formation, whereas knockdown of miR-132-3p could inhibit ESCC progression in vitro and in vivo. Importantly, dual-luciferase reporter assays showed that miR-132-3p could bind with the 3'-untranslated region of KCNK2 and inhibit KCNK2 gene expression. Knockdown or overexpression of KCNK2 could promote or suppress ESCC progression in vitro. These data suggest that heat stimulation can promote ESCC progression and miR-132-3p mediated this process by directly targeting KCNK2.

JAK3/STAT5b/PPARγ Pathway Mediates the Association between Di(2-ethylhexyl) Phthalate Exposure and Lipid Metabolic Disorder in Chinese Adolescent Students.

Our previous studies found that di (2-ethylhexyl) phthalate (DEHP) could disorder lipid metabolism in adolescents but the mechanisms underlying this association remained unclear. This study was undertaken to clarify the mediating effect of JAK3/STAT5/PPARγ on disorder lipid levels induced by DEHP in adolescents. We recruited 478 adolescent students (median age 18.1 years). The mRNA expression and DNA methylation levels of JAK3/STAT5/PPARγ were detected by real-time PCR and the MethylTarget, respectively. We used multiple linear regression to analyze the association between DEHP metabolites (MEHP, MEOHP, MEHHP, MECPP, MCMHP, and ΣDEHP) levels, mRNA expression, and DNA methylation levels. The mediating effect of JAK3/STAT5/PPARγ mRNA expression levels was examined by mediation analysis. We found that all DEHP metabolite levels were positively correlated with TC/HDL-C and LDL-C/HDL-C (P < 0.05). The MEOHP level was negatively associated with DNA methylation levels and positively associated with mRNA levels of PPARγ and STAT5b (P < 0.05). The MEHP level was negatively associated with the DNA methylation level and positively associated with the mRNA level of JAK3 (P < 0.05). Higher MEOHP was associated with a higher level of TC/HDL-C, the mediation analysis showed the mediation effect was 17.18% for the JAK3 level, 10.76% for the STAT5b level, and 11% for the PPARγ level. Higher MEHP was associated with a higher level of LDL-C/HDL-C, the mediation effect was 14.49% for the JAK3 level. In conclusion, DEHP metabolites decreased the DNA methylation levels, inducing the increase of the mRNA levels of JAK3/STAT5/PPARγ. In addition, the mRNA levels mediated the association between DEHP exposure and disorder lipid levels.

Role of COX-2/PGE2 signaling pathway in the apoptosis of rat ovarian granulosa cells induced by MEHP.

OBJECTIVE: MEHP, as the metabolite of DEHP, is a widely used environmental endocrine disruptor. Ovarian granulosa cells participate in maintaining the function of ovary and COX2/PGE2 pathway may regulate the function of granulosa cells. We aimed to explore how COX-2/PGE2 pathway affects cell apoptosis in ovarian granulosa cells caused by MEHP. METHODS: Primary rat ovarian granulosa cells were treated with MEHP (0, 200, 250, 300 and 350 µM) for 48 h. Adenovirus was used for over-expression of COX-2 gene. The cell viability was tested with CCK8 kits. The apoptosis level was tested by flow cytometry. The levels of PGE2 were tested with ELISA kits. The expression levels of COX-2/PGE2 pathway related genes, ovulation-related genes and apoptosis-related genes, were measured with RT-qPCR and Western blot. RESULTS: MEHP decreased the cell viability. After MEHP exposure, the cell apoptosis level increased. The level of PGE2 markedly decreased. The expression levels of COX-2/PGE2 pathway related genes, ovulation-related genes and anti-apoptotic genes decreased; the expression levels of pro-apoptotic genes increased. The apoptosis level was alleviated after over-expression of COX-2, and the level of PGE2 slightly increased. The expression levels of PTGER2 and PTGER4, and the levels of ovulation-related genes increased; the levels of pro-apoptotic genes decreased. CONCLUSION: MEHP can cause cell apoptosis by down-regulating the levels of ovulation-related genes via COX-2/PGE2 pathway in rat ovarian granulosa cells.

The effects of brominated flame retardants (BFRs) on pro-atherosclerosis mechanisms.

Brominated flame-retardants (BFRs) are environmental endocrine disruptors, comprising several pollutants, which potentially affect the endocrine system and cause dysfunction and disease. Widespread BFR exposure may cause multisystem toxicity, including cardiovascular toxicity in some individuals. Studies have shown that BFRs not only increase heart rate, induce arrhythmia and cardiac hypertrophy, but also cause glycolipid metabolism disorders, vascular endothelial dysfunction, and inflammatory responses, all of which potentially induce pre-pathological changes in atherosclerosis. Experimental data indicated that BFRs disrupt gene expression or signaling pathways, which cause vascular endothelial dysfunction, lipid metabolism-related disease, inflammation, and possibly atherosclerosis. Considerable evidence now suggests that BFR exposure may be a pro-atherosclerotic risk factor. In this study, we reviewed putative BFR effects underpinning pro-atherosclerosis mechanisms, and focused on vascular endothelial cell dysfunction, abnormal lipid metabolism, pro-inflammatory cytokine production and foam cell formation. Consequently, we proposed a scientific basis for preventing atherosclerosis by BFRs and provided concepts for further research.

ANRIL regulating the secretion of Muc5ac induced by atmospheric PM2.5 via NF-κB pathway in Beas-2B cells.

PM2.5 can cause airway inflammation and promote the excessive secretion of mucin 5ac (Muc5ac), which can further induce many respiratory diseases. Antisense non-coding RNA in the INK4 locus (ANRIL) might regulate the inflammatory responses mediated by nuclear factor kappa-B (NF-κB) signaling pathway. Beas-2B cells were used to clarify the role of ANRIL in the secretion of Muc5ac induced by PM2.5 . The siRNA was used to silence ANRIL expression. Normal and gene silenced Beas-2B cells were respectively exposed to different doses of PM2.5 for 6, 12, and 24 h. The survival rate of Beas-2B cells was detected by methyl thiazolyl tetrazolium (MTT) assay. Tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and Muc5ac levels were determined by enzyme linked immunosorbent assay (ELISA). The expression levels of NF-κB family genes and ANRIL were detected by real time polymerase chain reaction (PCR). The levels of NF-κB family proteins and NF-κB family phosphorylated proteins were determined using Western blot. Immunofluorescence experiments were performed to observe the nuclear transposition of RelA. PM2.5 exposure increased the levels of Muc5ac, IL-1ß and TNF-α, and ANRIL gene expression (p < .05). With the dose and time of PM2.5 exposure increasing, the protein levels of inhibitory subunit of nuclear factor kappa-B alpha (IκB-α), RelA, and NF-κB1 decreased, the protein levels of phosphorylated RelA (p-RelA) and phosphorylated NF-κB1 (p-NF-κB1) increased, and RelA nuclear translocation increased, which indicated that the NF-κB signaling pathway was activated (p < .05). Silencing ANRIL could decrease the levels of Muc5ac, IL-1ß, TNF-α, decrease NF-κB family genes expression, inhibit the degradation of IκB-α and the activation of NF-κB pathway (p < .05). ANRIL played a regulatory role in the secretion of Muc5ac and the inflammation induced by atmospheric PM2.5 via NF-κB pathway in Beas-2B cells. ANRIL could be a target for prevention and treatment of the respiratory diseases caused by PM2.5 .

The Relationship Between Colorectal Polyps and Serum Lipid Levels: A Systematic Review and Meta-analysis.

Colorectal polyp has been considered as the precancerous lesion of colorectal cancer, to which serum lipid levels are closely related. At present, there is no consensus on the relationship between colorectal polyps and serum lipid levels. We performed a meta-analysis to explore the effects of lipid levels on colorectal polyps. Relevant articles published from 2000 to 2020 were searched in PubMed, Web of Science, EMBASE, and Cochrane Library databases. The mean value and SD of serum lipid indexes and body mass index in colorectal polyps groups and control groups were extracted from the included articles. Combined weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated to assess the effect size of serum lipid levels on colorectal polyps. The publication bias of the included studies were assessed based on the Egger test. Thirty-seven articles containing 19,464 cases and 63,979 controls were included. There were no significant publication bias. The levels of high-density lipoprotein cholesterol in the cases were lower than those in the controls (WMD: -2.589 mg/dL, 95% CI: -3.273, -1.906). While the levels of triglyceride (WMD: 16.933 mg/dL, 95% CI: 13.131, 20.736), total cholesterol (WMD: 5.561 mg/dL, 95% CI: 3.477, 7.645), low-density lipoprotein cholesterol (WMD: 3.109 mg/dL, 95% CI: 0.859, 5.359) and body mass index (WMD: 0.747 mg/dL, 95% CI: 0.588, 0.906) were higher in the cases. Colorectal polyps were associated with serum lipid levels and obesity. Hyperlipidemia and obesity may be the risk factors for colorectal polyps.

Effect of Di-(2-ethylhexyl) phthalate on the hypothalamus-pituitary-thyroid axis in adolescent rat.

Di-(2-ethylhexyl) phthalate (DEHP) is extensively used in many personal care and consumer products, which results in widespread human exposure. Limited studies have suggested that exposure to DEHP may affect thyroid function, but little is known about the effect and mechanisms of DEHP exposure on the hypothalamic-pituitary-thyroid axis (HPTA). The present study was conducted to elucidate the potential mechanisms underlying DEHP disrupting the function of the HPTA. DEHP was administered to Wistar rats by gavage at 0, 5, 50, and 500 mg/kg/day for consecutive 28 days and then the rats were sacrificed within 24 h following the last dose. The hormone levels of HPTA were quantified with radioimmunoassay and enzyme-linked immunosorbent assay, the protein levels of thyrotropin-releasing hormone receptor (TRHR) and thyroid-stimulating hormone receptor (TSHR) were analyzed by Western blot and immunohistochemistry, and the expression levels of TRHR and TSHR mRNA were measured by quantitative real-time PCR. The low dose of DEHP increased the body weights of rats. Serum levels of T3, T4, FT3 and FT4 as well as protein and mRNA levels of TSHR decreased in rats treated with 50 mg/kg or 500 mg/kg DEHP compared with those of controls. Although the protein levels of TRH in the hypothalamus or protein and mRNA levels of TRHR in pituitary were up-regulated, serum levels of TSH did not change statistically in rats treated with DEHP. Therefore, DEHP can produce thyroid toxicity and may interfere with the secretion of pituitary TSH. In conclusion, DEHP could interfere with the balance of HPTA of adolescent rats, and disturb the homeostasis of thyroid related hormones and the expression levels of receptors.

Role of notch signaling pathway in Muc5ac secretion induced by atmospheric PM2.5 in rats.

BACKGROUND: The secretion of Muc5ac is closely related to the pathogenesis, treatment and prognosis of bronchial asthma. Atmospheric PM2.5 entered the airway can irritate and corrode the bronchial wall, affecting the expression and secretion of Muc5ac. However, the underlying mechanism is not clear. In this study, we investigated the role of the Notch signaling pathway in mucin section induced by atmospheric PM2.5 in rats. METHODS: Fifty rats were divided randomly into five groups: the control received physiological saline; the health, health Notch signaling pathway inhibition and asthma, asthma Notch signaling pathway inhibition groups received 7.5 mg/kg PM2.5. PM2.5 or saline was instilled into the trachea at 2-day intervals for two doses. IL-1ß, TNF-α and Muc5ac levels were detected by ELISA. The mRNA expression levels of Notch signaling pathway genes were detected by real time PCR. The levels of Notch signaling pathway protein were detected by western blot. RESULTS: The levels of Muc5ac in the lungs and TNF-α in serum of asthmatic rats exposed to PM2.5 was the highest, and when Notch signaling pathway was inhibited, the levels of Muc5ac in the lungs and tracheas and TNF-α in serum of asthmatic rats exposed to PM2.5 was significantly decreased. Hes1 mRNA expression level in trachea was the lowest in the asthma inhibition group; and inhibiting the Notch signaling pathway could decrease the mRNA and protein levels of Hes1 in rats' lung. The mRNA relative levels of Notch3 and Notch4 in rats' trachea, the protein levels of Notch3 in rats' lung, and the mRNA relative levels of Jagged1 and Jaggeed2 in rats' lung were more consist with the changes of Muc5ac, TNF-α and Hes1. CONCLUSION: Notch signaling pathway played an important role in Muc5ac secretion induced by atmospheric PM2.5 of the asthmatic rats' airways. Jagged1 and Jagged2 interacting with Notch3 and Notch4 regulated the expression of Hes1, further regulated TNF-α in the process of PM2.5 inducing the secretion of Muc5ac.

QAScore-An Unsupervised Unreferenced Metric for the Question Generation Evaluation.

Question Generation (QG) aims to automate the task of composing questions for a passage with a set of chosen answers found within the passage. In recent years, the introduction of neural generation models has resulted in substantial improvements of automatically generated questions in terms of quality, especially compared to traditional approaches that employ manually crafted heuristics. However, current QG evaluation metrics solely rely on the comparison between the generated questions and references, ignoring the passages or answers. Meanwhile, these metrics are generally criticized because of their low agreement with human judgement. We therefore propose a new reference-free evaluation metric called QAScore, which is capable of providing a better mechanism for evaluating QG systems. QAScore evaluates a question by computing the cross entropy according to the probability that the language model can correctly generate the masked words in the answer to that question. Compared to existing metrics such as BLEU and BERTScore, QAScore can obtain a stronger correlation with human judgement according to our human evaluation experiment, meaning that applying QAScore in the QG task benefits to a higher level of evaluation accuracy.

MUC5B regulates the airway inflammation induced by atmospheric PM2.5 in rats and A549 cells.

Atmospheric PM2.5 can induce airway inflammation and mucin secretion. MUC5B is required for airway defense. However, the research on the role of MUC5B in airway inflammation induced by atmospheric PM2.5 remains limited. This study was designed to explore the role of MUC5B in airway inflammation induced by atmospheric PM2.5. In vivo, Wistar rats were exposed to 0, 1.5, 7.5, 37.5 mg/ kg PM2.5 saline suspension via intratracheal instillation. HE staining and AB-PAS staining were used to observe the airway inflammation and goblet cell hyperplasia. In vitro, normal A549 cells and MUC5B-knockdown A549 cells were exposed to 0, 100, 200 and 400 µg/mL PM2.5 for 6 h, 12 h, 24 h and 48 h. ELISA was used to measure the levels of TNF-α and IL-1ß in serum and bronchoalveolar lavage fluid of rats and in cell culture. Real time-PCR and ELISA were used to quantify the mRNA and protein levels of MUC5B in trachea and lung of rats and in A549 cells. PM2.5 could cause the infiltration of inflammatory cells and increase the mucus secretions and goblet cell metaplasia. MUC5B is related to rats' airway inflammation induced by PM2.5. A549 cells exposed to PM2.5 in higher concentration and longer time, the protein level of MUC5B was significantly increased, while the levels of IL-1ß, TNF-α and MUC5B mRNA were significantly decreased. Compared with normal A549 cells, the levels of IL-1ß and TNF-α were significantly higher in Muc5b-knockdown cells. Atmospheric PM2.5 can induce airway inflammation and mucin secretion. MUC5B played a critical role in controlling the inflammatory response induced by PM2.5.

PM2.5 promoted lipid accumulation in macrophage via inhibiting JAK2/STAT3 signaling pathways and aggravating the inflammatory reaction.

BACKGROUND: Abnormal lipid accumulation in macrophages may lead to macrophages foaming, which is the most important pathological process of atherosclerosis. Atmospheric PM2.5 could enter the blood circulation and further affect the lipid metabolism of macrophages. But the underlying mechanism is not unclear. This study was undertaken to clarify the effect of PM2.5 on lipid metabolism in macrophages, and to explore the role of inflammatory reaction and JAK2/STAT3 signaling pathway in this process. METHOD: Macrophages derived from THP-1 cells were exposed to PM2.5 (0,100,200,400 µg/mL) for 6 h and 12 h. STAT3 agonist ColivelinTFA is used to specifically excite STAT3. The survival rate of macrophages was detected by CCK-8. The lipid levels in macrophages were detected by colorimetry. The levels of inflammatory factors secreted by macrophages were detected by ELISA. Q-PCR was used to detect the mRNA expression levels, and Western Blot was used to detect the protein expression levels of JAK2/STAT3 pathway genes. RESULT: The survival rate of macrophages was reduced by PM2.5, and the levels of TG, T-CHO and LDL-C of macrophages exposed to PM2.5 were increased. PM2.5 led to the increasing level of IL-6 and the decreasing level of IL-4, and the JAK2/STAT3 signaling pathway was inhibited by PM2.5. Colivelin TFA significantly decreased the increasing levels of TG, T-CHO and LDL-C levels, and increased the decreasing mRNA levels of IL-4, and LPL induced by PM2.5 (p < 0.05). DISCUSSION: PM2.5 could cause the lipid accumulation of macrophages by inhibiting the JAK2/STAT3 signaling pathway, and inflammatory responses may be involved in this process.

Effect of Notch pathway on lipid accumulation induced by mono-2-ethylhexyl phthalate on 3T3-L1 cells.

BACKGROUND: Mono-2-ethylhexyl phthalate (MEHP) is a major metabolite of di (2-ethylhexyl) phthalate (DEHP). Our previous researches have shown that MEHP can induce lipid accumulation in preadipocytes, while, the underlying mechanism is unclear. The present study was undertaken to clarify the effect of Notch pathway on lipid accumulation induced by MEHP. METHODS: 3T3-L1 preadipocytes were exposed to MEHP (0, 10, 50, 250 µM and 0.1%DMSO) for the whole differentiation phase. Then the level of TG and cell cycle were detected. RT-PCR was used to detect the mRNA expression and Western blot was used to detect the expression of protein by Notch pathway genes and lipid metabolic related genes. RESULTS: In this study, the level of TG in the 250 µM and 250 µM MEHP groups was significantly higher than that in the control, DMSO and 10 µM MEHP groups (P < 0.05). The relative mRNA level of Notch-1, Notch-3, Notch-4, Jagged-2 and Dll-4 in 250 µM group was higher than other groups (P < 0.05). The expression of Notch signal pathway proteins increased in MEHP treated groups, and the expression of Notch-2, Jagged-1, Jagged-2, Dll-1 and Dll-4 in 250 µM group were significantly higher than control group (P < 0.05). The expression of lipid metabolic related gene mRNA and protein increased in MEHP treated groups, and 250 µM MEHP group was higher than other groups (P < 0.05). The intracellular TG content was significantly correlated with the expression levels of Notch-1 and Jagged-2 mRNA (P < 0.05). CONCLUSION: In this study, we have found that MEHP exposure could increase the TG content in 3T3-L1 cells. The expression of Notch pathway mRNA and proteins were disturbed by the MEHP. Notch-1 and its ligand Jagged-2 play a critical role in the abnormal lipid metabolism in 3T3-L1 cells caused by MEHP.

CELF2 suppresses non-small cell lung carcinoma growth by inhibiting the PREX2-PTEN interaction.

The phosphoinositide 3-kinase (PI3-K)/Akt signaling pathway is important in the regulation of cell proliferation through its production of phosphatidylinositol 3,4,5-triphosphate (PIP3). Activation of this pathway is frequently observed in human cancers, including non-small cell lung carcinoma. The PI3-K/Akt pathway is negatively regulated by the dual-specificity phosphatase and tensin homolog (PTEN) protein. PTEN acts as a direct antagonist of PI3-K by dephosphorylating PIP3. Studies have shown that PTEN phosphatase activity is inhibited by PREX2, a guanine nucleotide exchanger factor (GEF). Multiple studies revealed that CELF2, an RNA binding protein, cooperates synergistically with PTEN as a tumor suppressor in multiple cancers. However, the underlying mechanism as to how CELF2 enhances PTEN activity remains unclear. Here, we report that CELF2 interacts with PREX2 and reduces the association of PREX2 with PTEN. Consistent with this observation, PTEN phosphatase activity is upregulated with CELF2 overexpression. In addition, overexpression of CELF2 represses both Akt phosphorylation and cell proliferation only in the presence of PTEN. In an ex vivo study, CELF2 gene delivery could significantly inhibit patient-derived xenografts (PDX) tumor growth. To further investigate the clinical relevance of this finding, we analyzed 87 paired clinical lung adenocarcinoma samples and the results showed that CELF2 protein expression is downregulated in tumor tissues and associated with poor prognosis. The CELF2 gene is located on the chromosome 10p arm, a region frequently lost in human cancers, including breast invasive carcinoma, low-grade glioma and glioblastoma. Analysis of TCGA datasets showed that CELF2 expression is also associated with shorter patient survival time in all these cancers. Overall, our work suggests that CELF2 plays a novel role in PI3-K signaling by antagonizing the oncogenic effect of PREX2.

Interconnections among major forms of regulated cell death.

As a basic biological phenomenon of cells, regulated cell death (RCD) has irreplaceable influence on the occurrence and development of many processes of life and diseases. RCD plays an important role in the stability of the homeostasis, the development of multiple systems and the evolution of organisms. Thus comprehensively understanding of RCD is undoubtedly helpful in the innovation of disease treatment. Recently, research on the underlying mechanisms of the major forms of RCD, such as apoptosis, autophagy, necroptosis, pyroptosis, paraptosis and neutrophils NETosis has made significant breakthroughs. In addition, the interconnections among them have attracted increasing attention from global scholars in the field of life sciences. Here, recent advances in RCD research field are discussed.

The effect of Notch signal pathway on PM2.5-induced Muc5ac in Beas-2B cells.

BACKGROUND: Atmospheric pollutants could induced over-expression of Muc5ac, which is a major pathological feature in acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD) and fatal asthma. Notch signaling pathway could promote mucus cell proliferation and mucus secretion. However, the effects of Notch signaling pathway on the airway mucus secretion induced by PM2.5 remain unknown. In this study, we investigated the role of the Notch signaling pathway on Muc5ac by atmospheric PM2.5 in Beas-2B cell. METHODS: The mRNA and protein levels of the Notch1-4, downstream target gene Hes1 and Muc5ac in the Notch signaling pathway were detected by qPCR and western after Beas-2B cells were exposed to PM2.5 of different concentrations for 12h, 24h, and 48h. RESULTS: The longer the exposure time and the higher the concentration of PM2.5, the lower the survival rate of Beas-2B cells. The expressions of Hes1 and Muc5ac in mRNA and protein were significantly increased after PM2.5 exposure. Correlation analysis indicated that there was a positive correlation between the expression of Muc5ac and Hes1 in mRNA and protein. CONCLUSION: Atmospheric PM2.5 can induce the express of Muc5ac, the Notch signaling pathway may be involved in the regulation of Muc5ac by Hes1.

Effect of NF-κB signal pathway on mucus secretion induced by atmospheric PM2.5 in asthmatic rats.

BACKGROUND: Exposure to PM2.5 can stimulate the mucus secretion of airway, affecting the development of bronchial asthma. NF-κB signal pathway plays an important role in inflammation and dysimmunity, what may contribute to the mucus secretion. The present study was undertaken to explore the effect of NF-κB signal pathway on mucus secretion induced by PM2.5 in rats with bronchial asthma. METHODS: Fifty rats (25 males and 25 females) were divided randomly into the control group, ovalbumin asthmatic model group, asthma low-, middle- and high-dose groups (n = 10, 5 males and 5 females each group). The control group, ovalbumin asthmatic model group received physiological saline; the asthma low-, middle- and high-dose groups received 1.5, 7.5 and 37.5 mg/kg PM2.5 on saline, which instilled into the trachea at 2-day intervals for two doses. Lung histopathology was observed by HE staining. The mRNA levels of NF-κB family gens were detected with real time PCR. IκB-α protein expression levels were detected with Western blot. IL-1ß, TNF-α and Muc5ac levels were detected by ELISA. RESULTS: Respiratory mucus secretion increased with increasing dose of PM2.5. Compared with healthy rats, the protein expression levels of IκB-α were significantly lower in the lung of asthmatic rats (p < 0.05), while the relative mRNA expression levels of NF-κB family genes in tracheal tissue and in lung were significantly higher in the asthmatic rats (p < 0.05). Serum IL-1ß levels were significantly higher in the high-dose group than in the control group. Muc5ac protein levels in the trachea were higher in the high-dose compared with the low-and middle-dose groups. CONCLUSION: Short-term exposure to a high concentration of PM2.5 could up-regulate the mRNA expression levels of NF-κB family genes, activate the NF-κB signal pathway, stimulate more IL-1ß and mucus secretion in rats with bronchial asthma. NF-κB signal pathway may regulate the level of IL-1ß, which could influence the mucus secretion induced by PM2.5 in asthmatic rats.

Exposure to PM2.5 affects blood lipid levels in asthmatic rats through notch signaling pathway.

BACKGROUND: Epidemiological studies have confirmed atmospheric PM2.5 could affect asthma, and dyslipidemia may be related to pathogenesis of asthma. Recent studies show Notch ligands had lipid combination domains which are responsible for regulating lipid levels. However, the effect of PM2.5 on asthmatic rats' lipid levels and the role of Notch signaling pathway is unclear. METHODS: Rats were treat with ovalbumin (OVA) to establish asthma models. Notch signaling pathway inhibitor (DAPT) was injected intraperitoneally. Asthmatic and healthy rats were exposed to different concentrations of PM2.5. Lung tissues were collected and the expression of Hes1 protein was detected by Western Blot. Blood samples were collected to detect the serum lipid levels. RESULTS: Hes1 expression levels in healthy and asthma pathway inhibition groups were lower than those in control groups. Compared with control group, rats exposed to PM2.5 in middle and high dose, the levels of TG and TC were decreased. Similar results were observed after exposure to the same concentration of PM2.5 in asthmatic rats. Rats, which were exposed to PM2.5 after being established the asthma model successfully, could exhibit more significant dyslipidemia than those with direct exposure. After Notch signaling pathway inhibited, TC and LDL in asthma pathway inhibition group were lower than those in healthy group. CONCLUSIONS: PM2.5 can affect the lipid levels of asthmatic rats through the Notch signaling pathway.