JNK modulates RAGE/β-catenin signaling and is essential for allergic airway inflammation in asthma

HMGB1 mediates epithelial-mesenchymal transition and fibrosis in silicosis via RAGE/β-catenin signaling

Epithelial-mesenchymal transition (EMT) is implicated in the pathogenesis of silicosis. High mobility group box 1 (HMGB1) has been found to induce EMT in fibrotic diseases. Previous studies have revealed a critical role of HMGB1 in silicosis, whereas the detail mechanisms still obscure. Here, we observed that HMGB1 protein was increased in the serum of silicosis patients and in the lung tissues of silicotic mice. The levels of HMGB1, receptor for advanced glycation end products (RAGE) and β-catenin protein were increased in the alveolar EMT cell model established by the treatment of transforming growth factor β1 (TGF-β1) and conditioned mediums derived from silica-stimulated macrophages. The activation of HMGB1, RAGE, β-catenin, EMT process, as well as cell migration triggered by TGF-β1 in RLE-6TN cells could be enhanced by treatment with recombinant HMGB1 protein (rHMGB1) and decreased by HMGB1 chemical inhibitor glycyrrhizin or RAGE inhibitor FPS-ZM1. And RAGE suppression could alleviate HMGB1-mediated the aggravation of β-catenin signaling, cell migration and EMT process induced by TGF-β1. Furthermore, both HMGB1 inhibition and RAGE knockout effectively alleviated the lung function impairment, EMT process, pulmonary inflammation and fibrosis in silicotic mice. These findings suggested that HMGB1 might promote EMT through RAGE/β-catenin axis in silicosis. And HMGB1 might constitute a therapeutic target for ameliorating the fibrosis of silicosis.

Electroacupuncture protects against the striatum of ischemia stroke by inhibiting the HMGB1/RAGE/p-JNK signaling pathways

The striatum (Str) is injured 20 min after permanent ischemic stroke, leading to neurological deficits. Here, we aimed to explore the effect of electroacupuncture (EA) on ischemic stroke and elucidate the possible underlying mechanism. Rat permanent middle cerebral artery occlusion (pMCAO) model, EA treatment, sham-EA (SEA) treatment, beam-balance test, hematoxylin and eosin (HE) staining, Nissl staining, immunofluorescence staining, and Western blot were used to investigate the role of EA in pMCAO. The results showed that balance ability and motor coordination were obviously injured after pMCAO. EA improved balance ability and motor coordination in pMCAO rats. EA reduced striatal injury by reducing the expression of high-mobility group box 1(HMGB1)/receptor for advanced glycation end products (RAGE)/phosphorylated C-Jun N-terminal kinase (p-JNK), whereas SEA did not. Thus, EA plays a neuroprotective role during pMCAO injury, which may be related to the inhibition of HMGB1/RAGE/p-JNK expression.

Lipocalin 2 (LCN2) Knockdown Regulates Treg/Th17 Balance to Improve Asthma in Mice

Purpose

Asthma substantially affects the quality of life and health of children. Lipocalin 2 (LCN2) is an immune-related protein, which is predicted to be highly expressed in asthma. Here, we investigated the role of LCN2 in ovalbumin (OVA)-induced asthma mouse model.

Methods

We knocked down LCN2 in an asthma mouse model and performed histopathological analysis using hematoxylin and eosin (H&E) staining assay. Differentiated cells were assessed using Diff-Quick staining assay. We investigated the regulatory T (Treg) cell/ T helper 17 (Th17) cell balance using flow cytometry and enzyme-linked immunosorbent assay (ELISA). Inflammatory factors were measured using quantitative real-time reverse transcription PCR (qRT-PCR). The involved pathways were assessed using Western blotting.

Results

LCN2 was upregulated in patients with asthma. OVA promoted pathological deterioration in the lungs, increased IgE levels in the plasma, and elevated the number of differentiated inflammatory cells, whereas LCN2 knockdown abrogated the OVA-induced effects. Additionally, the Treg/Th17 imbalance and increased inflammatory cytokine levels were improved by LCN2 knockdown in OVA-treated mice. Moreover, LCN2 knockdown reversed the activation of the janus kinase (JNK) pathway.

Conclusion

LCN2 knockdown improved the Treg/Th17 balance, alleviated inflammation, and inactivated the JNK pathway in OVA-induced asthma mouse model, suggesting that LCN2 may be a novel therapeutic target for asthma in children.

Mitoquinone ameliorated airway inflammation by stabilizing β-catenin destruction complex in a steroid-insensitive asthma model

BACKGROUND AND PURPOSE

Mitochondrial dysfunction is an essential part of the pathophysiology of asthma, and potential treatments that target the malfunctioning mitochondria have attracted widespread attention. We have previously demonstrated that aberrant epithelial β-catenin signaling played a crucial role in a toluene diisocyanate (TDI)-induced steroid-insensitive asthma model. The objective of this study was to determine if the mitochondrially targeted antioxidant mitoquinone(MitoQ) regulated the activation of β-catenin in TDI-induced asthma.

METHOD

Mice were sensitized and challenged with TDI to generate a steroid-insensitive asthma model. Human bronchial epithelial cells (16HBE) were exposed to TDI-human serum albumin (HSA) and ethidium bromide(EB) to simulate the TDI-induced asthma model and mitochondrial dysfunction.

RESULTS

MitoQ dramatically attenuated TDI-induced AHR, airway inflammation, airway goblet cell metaplasia, and collagen deposition and markedly protected epithelial mitochondrial functions by preserving mass and diminishing the production of reactive oxygen species (ROS). MitoQ administration stabilized β-catenin destruction complex from disintegration and inhibited the activation of β-catenin. Similarly, YAP1, an important constituent of β-catenin destruction complex, was inhibited by Dasatinib, which alleviated airway inflammation and the activation of β-catenin, and restored mitochondrial mass. In vitro, treating 16HBE cells with EB led to the activation of YAP1 and β-catenin signaling, decreased the expression of glucocorticoid receptors and up-regulated interleukin (IL)-1β, IL6 and IL-8 expression.

CONCLUSION

Our results indicated that mitochondria mediates airway inflammation by regulating the stability of the β-catenin destruction complex and MitoQ might be a promising therapeutic approach to improve airway inflammation and severe asthma.

AVAILABILITY OF DATA AND MATERIALS

The data that support the findings of this study are available from the corresponding author upon reasonable request. Some data may not be made available because of privacy or ethical restrictions.

A porcine model of early-onset scoliosis combined with thoracic insufficiency syndrome: Construction and transcriptome analysis

BACKGROUND

Early-onset scoliosis (EOS) is a scoliosis deformity caused by various reasons before the age of 10 years and is often combined with thoracic insufficiency syndrome (TIS) causing patients with difficulty in securing lung growth in the thoracic cage. Currently, there is a shortage of effective large animal models for evaluating EOS + TIS in therapeutic studies. Consequently, we propose to construct a porcine EOS + TIS model and evaluate its transcriptome changes by RNA sequencing.

METHODS

Piglets were constructed using unilateral posterior spine-tethering and ipsilateral rib-tethering in the EOS + TIS model, and X-ray and computed tomography (CT) were performed to assess growth changes in the spine, thoracic cage and lungs. The H&E and Masson staining was performed for pathological analysis of lung tissue. After RNA sequencing of lung tissues, data were analyzed for differential expression of mRNA, functional enrichment analysis (GO, KEGG and GSEA) and protein-protein interaction (PPI) network construction, and differential expression of hub gene was verified by RT-qPCR.

RESULTS

In the model group, growth (body weight and length) of piglets was significantly delayed; fusion of ribs occurred and cobb angle changes in the coronal and sagittal planes were significantly enlarged; total lung volume (TLV) was significantly reduced, especially at the T7-T10 level. Pathological analysis revealed that, in the model lung tissue, the alveolar wall of was poorly perfused, the alveolar space was enlarged, the number and size of alveoli were significantly reduced, and it was accompanied by collagen fiber deposition. Moreover, a total of 432 differentially expressed mRNAs (DE-mRNAs) were identified in model lung tissues, which contained 262 down-regulated and 170 up-regulated DE-mRNAs, and they were mainly involved in the regulation of immunity, inflammation, cell cycle and extracellular matrix. A PPI network containing 71 nodes and 158 edges was constructed based on all DE-mRNAs, and JUN, CCL2, EGR1, ATF3, BTG2, DUSP1 and THBS1 etc. were hub gene.

CONCLUSIONS

Overall, we constructed a porcine model that was capable of replicating the common clinical features of EOS + TIS such as rib fusion, asymmetric thoracic cage, increased cobb angle, decreased TLV, and pulmonary hypoplasia. Also, we revealed transcriptomic changes in the EOS + TIS model that may cause pulmonary hypoplasia.

Airway epithelial ITGB4 deficiency induces airway remodeling in a mouse model

BACKGROUND

Airway epithelial cells (AECs) with impaired barrier function contribute to airway remodeling through the activation of epithelial-mesenchymal trophic units (EMTUs). Although the decreased expression of ITGB4 in AECs is implicated in the pathogenesis of asthma, how ITGB4 deficiency impacts airway remodeling remains obscure.

OBJECTIVE

This study aims to determine the effect of epithelial ITGB4 deficiency on the barrier function of AECs, asthma susceptibility, airway remodeling, and EMTU activation.

METHODS

AEC-specific ITGB4 conditional knockout mice (ITGB4^-/-) were generated and an asthma model was employed by the sensitization and challenge of house dust mite (HDM). EMTU activation-related growth factors were examined in ITGB4-silenced primary human bronchial epithelial cells of healthy subjects after HDM stimulation. Dexamethasone, the inhibitors of JNK phosphorylation or FGF2 were administered for the identification of the molecular mechanisms of airway remodeling in HDM-exposed ITGB4^-/- mice.

RESULTS

ITGB4 deficiency in AECs enhanced asthma susceptibility and airway remodeling by disrupting airway epithelial barrier function. Aggravated airway remodeling in HDM-exposed ITGB4^-/- mice was induced through the enhanced activation of EMTU mediated by Src homology domain 2-containing protein tyrosine phosphatase 2/c-Jun N-terminal kinase/Jun N-terminal kinase-dependent transcription factor/FGF2 (SHP2/JNK/c-Jun/FGF2) signaling pathway, which was partially independent of airway inflammation. Both JNK and FGF2 inhibitors significantly inhibited the aggravated airway remodeling and EMTU activation in HDM-exposed ITGB4^-/- mice.

CONCLUSIONS

Airway epithelial ITGB4 deficiency induces airway remodeling in a mouse model of asthma through enhanced EMTU activation that is regulated by the SHP2/JNK/c-Jun/FGF2 pathway.

[Inhibition of TAK1 aggravates airway inflammation by increasing RIPK1 activity and promoting macrophage death in a mouse model of toluene diisocyanate-induced asthma]

OBJECTIVE

To explore the effect of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) on toluene diisocyanate (TDI)-induced allergic airway inflammation in mice.

METHODS

Thirty-two mice were randomly divided into AOO group, AOO+5Z-7-Oxozeaenol group, TDI group, and TDI+5Z-7-Oxozeaenol group. Another 32 mice were randomly divided into AOO group, TDI group, TDI +5Z-7-Oxozeaenol group, and TDI +5Z-7-Oxozeaenol + Necrostatin-1 group. TAK1 inhibitor (5Z-7-Oxozeaenol, 5 mg/kg) and/or RIPK1 inhibitor (Necrostatin-1, 5 mg/kg) were used before each challenge. Airway responsiveness, airway inflammation and airway remodeling were assessed after the treatments. We also examined the effect of TDI-human serum albumin (TDI-HSA) conjugate combined with TAK1 inhibitor on the viability of mouse mononuclear macrophages (RAW264.7) using CCK8 assay. The expressions of TAK1, mitogen-activated protein kinase (MAPK) and receptor interacting serine/threonine protease 1 (RIPK1) signal pathway in the treated cells were detected with Western blotting. The effects of RIPK1 inhibitor on the viability of RAW264.7 cells and airway inflammation of the mouse models of TDI-induced asthma were evaluated.

RESULTS

TAK1 inhibitor aggravated TDI-induced airway inflammation, airway hyper responsiveness and airway remodeling in the mouse models (P < 0.05). Treatment with TAK1 inhibitor significantly decreased the viability of RAW264.7 cells, which was further decreased by co-treatment with TDI-HSA (P < 0.05). TAK1 inhibitor significantly decreased the level of TAK1 phosphorylation and activation of MAPK signal pathway induced by TDI-HSA (P < 0.05). Co-treatment with TAK1 inhibitor and TDI-HSA obviously increased the level of RIPK1 phosphorylation and caused persistent activation of caspase 8 (P < 0.05). RIPK1 inhibitor significantly inhibited the reduction of cell viability caused by TAK1 inhibitor and TDI-HSA (P < 0.05) and alleviated the aggravation of airway inflammation induced by TAK1 inhibitors in TDI-induced mouse models (P < 0.05).

CONCLUSION

Inhibition of TAK1 aggravates TDI-induced airway inflammation and hyperresponsiveness and may increase the death of macrophages by enhancing the activity of RIPK1 and causing persistent activation of caspase 8.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

CpG Oligodeoxynucleotides Attenuate OVA-Induced Allergic Airway Inflammation via Suppressing JNK-Mediated Endoplasmic Reticulum Stress

Purpose

CpG-ODN has been found to attenuate allergic airway inflammation in our previous study. Here, we aimed to further investigate whether CpG-ODN exerts such effect via regulating endoplasmic reticulum (ER) stress and revealed the underlying mechanism.

Methods

Five-week-old C57BL/6 mice were randomly grouped and treated with or without CpG-ODN or/and SP600125. Meantime, RAW264.7 cells were used to investigate the effect of CpG-ODN on OVA-induced ER stress in vitro. The cellularity of bronchoalveolar lavage fluid (BALF) was classified and counted after Wright-Giemsa staining. HE and PAS staining methods were applied to analyze airway inflammation. The protein levels of IL-4, IL-5, IL-13, p-JNK, JNK, CHOP, XBP1, ATF6α and GRP78 in lung tissues were detected by Western blotting. Correspondingly, the ER stress markers were detected by Western blotting and immunofluorescence in RAW264.7 cells.

Results

In OVA-induced allergic airway inflammation, CpG-ODN significantly suppressed inflammatory cells infiltration, goblet cell hyperplasia and the protein expression of Th2 cytokines. Moreover, OVA exposure strongly increased the activation of ER stress with higher protein expressions of CHOP, XBP1, ATF6α and GRP78. However, these OVA-induced increase of ER stress markers were markedly suppressed by CpG-ODN treatment. In addition, exposure to OVA significantly increased the phosphorylation of JNK, which was significantly reduced by CpG-ODN treatment. Remarkably, single treatment of SP600125, an antagonist of JNK, functioned similarly as CpG-ODN in mitigating allergic airway inflammation and suppressing OVA-induced activation of ER stress; however, no significant synergistic effect was evidenced by combined treatment of SP600125 and CpG-ODN. Furthermore, in OVA-stimulated RAW264.7 cells, we also found that OVA stimulation increased the expressions of ER stress markers, and CpG-ODN significantly reduced their expression levels via suppressing the phosphorylation of JNK.

Conclusion

These results indicated that CpG-ODN mitigates allergic airway inflammation via suppressing the activation of JNK-medicated ER stress.