c-Ets1 inhibits the interaction of NF-κB and CREB, and downregulates IL-1β-induced MUC5AC overproduction during airway inflammation

IL-1β Promotes Expansion of IL-33+ Lung Epithelial Stem Cells Following RSV Infection During Infancy

Respiratory syncytial virus (RSV)-induced immunopathogenesis and disease severity in neonatal mice and human infants have been related to elevated pulmonary IL-33. Thus, targeting IL-33 has been suggested as a potential therapy for respiratory viral infections. Yet, the regulatory mechanisms on IL-33 during early life remain unclear. Here, using a neonatal mouse model of RSV, we demonstrate that IL-1β positively regulates but is not required for RSV-induced expression of pulmonary IL-33 in neonatal mice early after the initial infection. Exogenous IL-1β upregulates RSV-induced IL-33 expression by promoting the proliferation of IL-33pos lung epithelial stem/progenitor cells (EpiSPC). These cells are exclusively detected in RSV-infected neonatal rather than adult mice, partially explaining the IL-1β-independent IL-33 expression in RSV-infected adult mice. Furthermore, IL-1β aggravates IL-33 mediated Th2 biased immunopathogenesis upon reinfection. Collectively, our study demonstrates that IL-1β exacerbates IL-33 mediated RSV immunopathogenesis by promoting the proliferation of IL-33pos EpiSPC in early life.

Endoplasmic reticulum stress/XBP1 promotes airway mucin secretion under the influence of neutrophil elastase

Endoplasmic reticulum (ER) stress is an important reaction of airway epithelial cells in response to various stimuli, and may also be involved in the mucin secretion process. In the present study, the effect of ER stress on neutrophil elastase (NE)-induced mucin (MUC)5AC production in human airway epithelial cells was explored. 16HBE14o-airway epithelial cells were cultured and pre-treated with the reactive oxygen species (ROS) inhibitor, N-acetylcysteine (NAC), or the ER stress chemical inhibitor, 4-phenylbutyric acid (4-PBA), or the cells were transfected with inositol-requiring kinase 1α (IRE1α) small interfering RNA (siRNA) or X-box-binding protein 1 (XBP1) siRNA, respectively, and subsequently incubated with NE. The results obtained revealed that NE increased ROS production in the 16HBE14o-cells, with marked increases in the levels of ER stress-associated proteins, such as glucose-regulated protein 78 (GRP78), activating transcription factor 6 (ATF6), phosphorylated protein kinase R-like endoplasmic reticulum kinase (pPERK) and phosphorylated (p)IRE1α. The protein and mRNA levels of spliced XBP1 were also increased, and the level of MUC5AC protein was notably increased. The ROS scavenger NAC and ER stress inhibitor 4-PBA were found to reduce ER stress-associated protein expression and MUC5AC production and secretion. Further analyses revealed that MUC5AC secretion was also attenuated by IRE1α and XBP1 siRNAs, accompanied by a decreased mRNA expression of spliced XBP1. Taken together, these results demonstrate that NE induces ER stress by promoting ROS production in 16HBE14o-airway epithelial cells, leading to increases in MUC5AC protein production and secretion via the IRE1α and XBP1 signaling pathways.

Andrographolide sulfate inhibited NF-κB activation and alleviated pneumonia induced by poly I:C in mice

Pneumonia is a common illness that continues to be the major killer of remaining to be a significant source of morbidity and mortality in the patient population. Many microorganisms cause pneumonia, and now concern is turning to the importance of the cause the new therapies for viral pneumonia. In the current study, we report the effect of andrographolide sulfonate, a water-soluble form of andrographolide (trade name: Xi-Yan-Ping Injection), on poly I: C-induced pneumonia. Andrographolide sulfonate was administrated through intraperitoneal injection to mice with poly I: C-induced pneumonia. Recruitment of airway inflammatory cells, alteration of lung histological induced by Poly I: C were significantly ameliorated by andrographolide sulfonate. The protein levels of pro-inflammatory cytokines in bronchoalveolar fluid (BALF) and serum were reduced by andrographolide sulfonate treatment. The levels of MUC5AC and MUC5B in lung tissue were also suppressed. These results reveal that andrographolide sulfate remarkably alleviated pneumonia induced by poly I:C in mice. Moreover, andrographolide sulfonate markedly inhibited the activation of nuclear factor-κB (NF-κB). Taken together, we demonstrated that andrographolide sulfonate ameliorated poly I: C-induced pneumonia in mice, suggesting the possible use of andrographolide sulfonate for virus-induced pneumonia in clinical.

MiR-532-5p suppresses renal cancer cell proliferation by disrupting the ETS1-mediated positive feedback loop with the KRAS-NAP1L1/P-ERK axis

Background

Despite the fact that miRNAs play pivotal roles in various human malignancies, their molecular mechanisms influencing RCC are poorly understood.

Methods

The expression of miRNAs from RCC and paired normal renal specimens was analysed by a combined computational and experimental approach using two published datasets and qRT-PCR assays. The functional role of these miRNAs was further identified by overexpression and inhibition assays in vivo and in vitro. Western blots, luciferase assays, and chromatin immunoprecipitation were performed to investigate the potential mechanisms of these miRNAs.

Results

Bioinformatics analysis and qRT-PCR revealed that miR-532-5p was one of the most heavily downregulated miRNAs. Overexpression of miR-532-5p inhibited RCC cell proliferation, while knockdown of miR-532-5p promoted cell proliferation. Mechanistic analyses indicated that miR-532-5p directly targets KRAS and NAP1L1. Interestingly, ETS1 suppressed the transcription of miR-532-5p by directly binding a special region of its promoter. Moreover, high levels of ETS1, as an oncogene in RCC, were significantly associated with poor survival in a large cohort of RCC specimens.

Conclusions

Our work presents a road map for the prediction and validation of a miR-532-5p/KRAS-NAP1L1/P-ERK/ETS1 axis feedback loop regulating cell proliferation, which could potentially provide better therapeutic avenues for treating RCC.

Regulation of Airway Inflammation by G-protein Regulatory Motif Peptides of AGS3 protein

Respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), and lung infections have critical consequences on mortality and morbidity in humans. The aims of the present study were to examine the mechanisms by which CXCL12 affects MUC1 transcription and airway inflammation, which depend on activator of G-protein signaling (AGS) 3 and to identify specific molecules that suppress CXCL12-induced airway inflammation by acting on G-protein-coupled receptors. Herein, AGS3 suppresses CXCL12-mediated upregulation of MUC1 and TNFα by regulating Gα_i. We found that the G-protein regulatory (GPR) motif peptide in AGS3 binds to Gα_i and downregulates MUC1 expression; in contrast, this motif upregulates TNFα expression. Mutated GPR Q34A peptide increased the expression of MUC1 and TGFβ but decreased the expression of TNFα and IL-6. Moreover, CXCR4-induced dendritic extensions in 2D and 3D matrix cultures were inhibited by the GPR Q34A peptide compared with a wild-type GPR peptide. The GPR Q34A peptide also inhibited CXCL12-induced morphological changes and inflammatory cell infiltration in the mouse lung, and production of inflammatory cytokines in bronchoalveolar lavage (BAL) fluid and the lungs. Our data indicate that the GPR motif of AGS3 is critical for regulating MUC1/Muc1 expression and cytokine production in the inflammatory microenvironment.

A novel dissociative steroid VBP15 reduces MUC5AC gene expression in airway epithelial cells but lacks the GRE mediated transcriptional properties of dexamethasone

Overproduction of secretory mucins contributes to morbidity/mortality in inflammatory lung diseases. Inflammatory mediators directly increase expression of mucin genes, but few drugs have been shown to directly repress mucin gene expression. IL-1β upregulates the MUC5AC mucin gene in part via the transcription factors NFκB while the glucocorticoid Dexamethasone (Dex) transcriptionally represses MUC5AC expression by Dex-activated GR binding to two GRE cis-sites in the MUC5AC promoter in lung epithelial cells. VBP compounds (ReveraGen BioPharma) maintain anti-inflammatory activity through inhibition of NFκB but exhibit reduced GRE-mediated transcriptional properties associated with adverse side-effects and thus have potential to minimize harmful side effects of long-term steroid therapy in inflammatory lung diseases. We investigated VBP15 efficacy as an anti-mucin agent in two types of airway epithelial cells and analyzed the transcription factor activity and promoter binding associated with VBP15-induced MUC5AC repression. VBP15 reduced MUC5AC mRNA abundance in a dose- and time-dependent manner similar to Dex in the presence or absence of IL-1β in A549 and differentiated human bronchial epithelial cells. Repression was abrogated in the presence of RU486, demonstrating a requirement for GR in the VBP15-induced repression of MUC5AC. Inhibition of NFκB activity resulted in reduced baseline expression of MUC5AC indicating that constitutive activity maintains MUC5AC production. Chromatin immunoprecipitation analysis demonstrated lack of GR and of p65 (NFκB) binding to composite GRE domains in the MUC5AC promoter following VBP15 exposure of cells, in contrast to Dex. These data demonstrate that VBP15 is a novel anti-mucin agent that mediates the reduction of MUC5AC gene expression differently than the classical glucocorticoid, Dex.

Association of E26 Transformation Specific Sequence 1 Variants with Rheumatoid Arthritis in Chinese Han Population

OBJECTIVE

E26 transformation specific sequence 1 (ETS-1) belongs to the ETS family of transcription factors that regulate the expression of various immune-related genes. Increasing evidence indicates that ETS-1 could contribute to the pathogenesis of autoimmune disease. Recent research has provided evidence that ETS-1 might correlate with rheumatoid arthritis (RA), but it's not clearly defined. In this study, we aimed to identify whether polymorphisms of ETS-1 play a role in Rheumatoid arthritis (RA) susceptibility and development in Chinese Han population.

METHODS

Four single nucleotide polymorphisms (SNPs) within ETS-1 were selected based on HapMap data and previous associated studies. Whole blood and serum samples were obtained from 158 patients with RA and 192 healthy subjects. Genotyping was performed with polymerase chain reaction-high resolution melting (PCR-HRM) assay and the data was analyzed using SPSS17.0.

RESULTS

A significantly positive correlation was observed between the SNP rs73013527 of ETS-1 and RA susceptibility, DAS28 and CRP (P<0.001, P = 0.001, and P = 0.028, respectively). Carriers of the haplotype CCT or TCT for rs4937333, rs11221332 and rs73013527 were associated with decreased risk of RA as compared to controls. No statistical significant difference was observed in the distribution of rs10893872, rs4937333 and rs11221332 genotypes between RA patients and controls.

CONCLUSIONS

Our data further supports that ETS-1 has a relevant role in the pathogenesis and development of RA. Allele T of rs73013527 plays a protective role in occurrence of RA but a risk factor in the high disease activity. Rs10893872, rs11221332 and rs4937333 are not associated with RA susceptibility and clinical features.

Role of p38 MAPK and STAT3 in lipopolysaccharide-stimulated mouse alveolar macrophages

Excessive production of inflammatory mediators is an important feature of inflammatory lung disease. In macrophages, mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription-3 (STAT3) are crucial mediators for the production of proinflammatory cytokines. In the present study, the role of MAPK and STAT3 on tumor necrosis factor (TNF)-α and interleukin (IL)-10 production was investigated in mouse alveolar macrophages. The levels of TNF-α and IL-10 in lipopolysaccharide (LPS; 100 ng/ml)-stimulated MH-S cell lines were measured by an enzyme-linked immunosorbent assay, with or without p38 inhibitor (SB203580; 5, 10 or 15 μM) intervention. Phosphorylated STAT3 (p-STAT3) expression was examined by western blot analysis and immunocytochemistry following LPS stimulation for 15 or 30 min. Antibodies against STAT3 were used to verify comparable sample loading. Cells stimulated with LPS showed significantly increased levels of p-STAT3 protein (P<0.05) when compared with the baseline levels. TNF-α and IL-10 protein levels also increased following LPS stimulation (P<0.05). By contrast, treatment with the p38 inhibitor, SB203580, decreased the levels of p-STAT3, TNF-α and IL-10 (P<0.05) following LPS stimulation. SB203580 was shown to inhibit LPS-stimulated TNF-α expression (P<0.05) in a concentration-dependent manner, reaching significance at a concentration of 10 μM. However, the inhibition of IL-10 expression was not concentration-dependent. Therefore, LPS-stimulated overproduction of TNF-α and IL-10 is mediated at least partially by the MAPK pathway. Inhibition of p38 prevented LPS-induced STAT3 phosphorylation, indicating an interaction between the STAT3 and MAPK signaling pathways.

IL-1β induction of MUC5AC gene expression is mediated by CREB and NF-κB and repressed by dexamethasone

Chronic airway diseases are characterized by inflammation and mucus overproduction. The MUC5AC mucin gene is upregulated by the proinflammatory cytokine interleukin-1 β (IL-1β) via activation of cAMP response element-binding protein (CREB) in the NCI-H292 cancer cell line and nuclear factor-κB (NF-κB) in the HBE1 transformed cell line, with each transcription factor binding to a cognate cis site in the proximal or distal region, respectively, of the MUC5AC promoter. We utilized primary differentiated human bronchial epithelial (HBE) and A549 lung adenocarcinoma cells to further investigate the contributions of CREB and NF-κB subunits to the IL-1β-induced upregulation of MUC5AC. Data show that ligand binding of IL-1β to the IL-1β receptor is required to increase MUC5AC mRNA abundance. Chromatin immunoprecipitation analyses show direct binding of CREB to the previously identified cAMP response element site and binding of p65 and p50 subunits to a novel NF-κB site in a mucin-regulatory domain in the proximal promoter and to a previously identified NF-κB site in the distal promoter. P50 binds to both NF-κB sites at 1 h following IL-1β exposure, but is replaced at 2 h by p65 in A549 cells and by a p50/p65 heterodimer in HBE cells. Thus IL-1β activates multiple domains in the MUC5AC promoter but exhibits some cell-specific responses, highlighting the complexity of MUC5AC transcriptional regulation. Data show that dexamethasone, a glucocorticoid that transcriptionally represses MUC5AC gene expression under constitutive conditions, also represses IL-1β-mediated upregulation of MUC5AC gene expression. A further understanding of mechanisms mediating MUC5AC regulation should lead to a honing of therapeutic approaches for the treatment of mucus overproduction in inflammatory lung diseases.

Src homology 2-containing protein tyrosine phosphatase-2 acts as a negative regulator for MUC5AC transcription via the inhibition of the ERK1/2 MAPK signalling pathway in the airway

AIMS

Mucus hypersecretion has been frequently observed in inflammation respiratory diseases. However, the negative regulators for mucus overproduction have not been readily identified. Our work focused on identifying novel negative regulator that modulates mucus overproduction in the human respiratory system. Herein, we examined whether H2 O2 could induce MUC5AC transcription in a dose-dependent manner and activate tyrosine phosphatase (SHP)-2 in human airway epithelial cells.

METHODS

We performed qRT-PCR to detect the changes in MUC5AC transcription and dot-blotting analysis to investigate MUC5AC secretion as regulated by SHP-2.

RESULTS

H2 O2 induced MUC5AC transcription in a dose-dependent manner and dramatically activated SHP-2. In addition, whereas wild-type SHP-2 completely inhibited H2 O2 -induced MUC5AC transcription, siRNA-SHP-2 restored it interestingly, suggesting that SHP-2 may act as a negative regulator for mucus overproduction and hypersecretion in the human respiratory tract. Moreover, SHP-2 inhibited the ERK1/2 MAPK pathway, thus abolishing the signalling for MUC5AC transcription.

CONCLUSION

We found that H2 O2 induced SHP-2 activation, which acted as a suppressor in H2 O2 signalling to regulate MUC5AC transcription in the airway.

Sexual dimorphism of thyroid reactive oxygen species production due to higher NADPH oxidase 4 expression in female thyroid glands

BACKGROUND

Dual oxidases (DUOX1 and DUOX2) are NADPH oxidases (NOX) involved in hydrogen peroxide production necessary for thyroid hormonogenesis, but recently, the NOX4 has also been described in the thyroid gland. The prevalence of thyroid disease is higher in women, and the basis for this difference might involve a higher oxidative stress level in the female thyroid gland. Hence, we aimed at evaluating whether the function and the expression of enzymes involved in the thyroid redox balance differ between females and males.

METHODS

DUOX1, DUOX2, NOX4, glutathione peroxidase (GPx), and catalase activities and expression levels were evaluated in the thyroids of prepubertal and adult male and female rats. The mRNA levels of DUOXA1 and DUOXA2, the DUOX maturation factors, and of p22phox and Poldip2 (subunits of NOX4) were also determined.

RESULTS

A higher calcium-independent H(2)O(2) production was detected in the adult female rat thyroid, being higher in the estrous phase of the cycle. Moreover, the expression of NOX4 and Poldip2 mRNA was higher in the thyroids of adult female rats, as well as in PCCL3 cells treated with 17β-estradiol. The GPx1 mRNA expression was higher in adult female thyroids, while GPx2 and GPx3 mRNA and total GPx activity were not significantly different. Catalase mRNA expression and activity, together with thyroid thiol levels were significantly lower in the adult female rat thyroid.

CONCLUSIONS

Taken together, our results show that the thyroid gland of female rats is exposed to higher oxidative stress levels due both to increased reactive oxygen species (ROS) production through NOX4, and decreased ROS degradation.