Role of the extracellular signal-regulated kinase 1/2 signaling pathway in the process of thrombin-promoting airway remodeling in ovalbumin-allergic rats

Ankyrin-repeat and SOCS box-containing protein 9 (ASB9) regulates ovarian granulosa cells function and MAPK signaling

Ankyrin-repeat and SOCS box-containing proteins (ASB) interact with the elongin B-C adapter via their SOCS box domain and with the cullin and ring box proteins to form E3 ubiquitin ligase complexes within the protein ubiquitination pathway. ASB9 in particular is a differentially expressed gene in ovulatory follicles (OFs) induced by the luteinizing hormone (LH) surge or hCG injection in ovarian granulosa cells (GC) while downregulated in growing dominant follicles. Although ASB9 has been involved in biological processes such as protein modification, the signaling network associated with ASB9 in GC is yet to be fully defined. We previously identified and reported ASB9 interactions and binding partners in GC including PAR1, TAOK1, and TNFAIP6/TSG6. Here, we further investigate ASB9 effects on target binding partners regulation and signaling in GC. CRISPR/Cas9-induced inhibition of ASB9 revealed that ASB9 regulates PAR1, TAOK1, TNFAIP6 as well as genes associated with proliferation and cell cycle progression such as PCNA, CCND2, and CCNE2 while CCNA2 was not affected. Inhibition of ASB9 was also associated with increased GC number and decreased caspase3/7 activity, CASP3 expression, and BAX/BCL2 ratio. Furthermore, ASB9 induction in OF in vivo 24 h post-hCG is concomitant with a significant decrease in phosphorylation levels of MAPK3/1 while pMAPK3/1 levels increased following ASB9 inhibition in GC in vitro. Together, these results provide strong evidence for ASB9 as a regulator of GC activity and function by modulating MAPK signaling likely through specific binding partners such as PAR1, therefore controlling GC proliferation and contributing to GC differentiation into luteal cells.

Mas receptor activation attenuates allergic airway inflammation via inhibiting JNK/CCL2-induced macrophage recruitment

BACKGROUND

Defective absorption of acute allergic airway inflammation is involved in the initiation and development of chronic asthma. After allergen exposure, there is a rapid recruitment of macrophages around the airways, which promote acute inflammatory responses. The Ang-(1-7)/Mas receptor axis reportedly plays protective roles in various tissue inflammation and remodeling processes in vivo. However, the exact role of Mas receptor and their underlying mechanisms during the pathology of acute allergic airway inflammation remains unclear.

OBJECTIVE

We investigated the role of Mas receptor in acute allergic asthma and explored its underlying mechanisms in vitro, aiming to find critical molecules and signal pathways.

METHODS

Mas receptor expression was assessed in ovalbumin (OVA)-induced acute asthmatic murine model. Then we estimated the anti-inflammatory role of Mas receptor in vivo and explored expressions of several known inflammatory cytokines as well as phosphorylation levels of MAPK pathways. Mas receptor functions and underlying mechanisms were studied further in the human bronchial epithelial cell line (16HBE).

RESULTS

Mas receptor expression decreased in acute allergic airway inflammation. Multiplex immunofluorescence co-localized Mas receptor and EpCAM, indicated that Mas receptor may function in the bronchial epithelium. Activating Mas receptor through AVE0991 significantly alleviated macrophage infiltration in airway inflammation, accompanied with down-regulation of CCL2 and phosphorylation levels of MAPK pathways. Further studies in 16HBE showed that AVE0991 pre-treatment inhibited LPS-induced or anisomycin-induced CCL2 increase and THP-1 macrophages migration via JNK pathways.

CONCLUSION

Our findings suggested that Mas receptor activation significantly attenuated CCL2 dependent macrophage recruitments in acute allergic airway inflammation through JNK pathways, which indicated that Mas receptor, CCL2 and phospho-JNK could be potential targets against allergic airway inflammation.

Effects of Thrombin on the Neurovascular Unit in Cerebral Ischemia

Cerebral ischemia is a cerebrovascular disease with high morbidity and mortality that poses a significant burden on society and the economy. About 60% of cerebral ischemia is caused by thrombus, and the formation of thrombus proceeds from insoluble fibrin, following its transformation from liquid fibrinogen. In thrombus-induced ischemia, increased permeability of the blood-brain barrier (BBB), followed by the extravasation of blood components into the brain results in an altered brain microenvironment. Changes in the brain microenvironment affect brain function and the neurovascular unit (NVU), the working unit of the brain. Recent studies have reported that coagulation factors interact with the NVU and its components, but the specific function of this interaction is highly speculative and warrants further investigations. In this article, we reviewed the role of coagulation factors in cerebral ischemia and the role of coagulation factors in thrombosis. Additionally, the influence of thrombin on the NVU is introduced, as well as in the function of NVU, which may help to explore part of brain injury mechanism during ischemia. Lastly, we propose some novel therapeutic approaches on ischemic stroke by reducing the risk of coagulation.

Clinical relevance of understanding mitogen-activated protein kinases involved in asthma

Introduction: Mitogen-activated protein kinases (MAPKs) are a large family of evolutionary conserved intracellular enzymes that play a pivotal role in signaling pathways mediating the biologic actions of a wide array of extracellular stimuli.Areas covered: MAPKs are implicated in most pathogenic events involved in asthma, including both inflammatory and structural changes occurring in the airways. Indeed, MAPKs are located at the level of crucial convergence points within the signal transduction networks activated by many cytokines, chemokines, growth factors, and other inducers of bronchial inflammation and remodeling such as immunoglobulin E (IgE) and oxidative stress.Expert opinion: Therefore, given the growing importance of MAPKs in asthma pathobiology, these signaling enzymes are emerging as key intracellular pathways whose upstream activation can be inhibited by biological drugs such as anti-cytokines and anti-IgE.

TIPE2 is negatively correlated with tissue factor and thrombospondin-1 expression in patients with bronchial asthma

The interaction between inflammatory processes and a hypercoagulant state may aggravate the severity of asthma and stimulate the airway remodeling of asthma. The aim of the current study was to evaluate the association between the negative inflammatory regulator tumor necrosis factor α induced protein-8 like-2 (TIPE2) and the coagulating substances tissue factor (TF) and thrombospondin-1 (TSP-1) in patients with bronchial asthma. Compared with healthy controls, TIPE2 expression was significantly downregulated, whereas TF expression was upregulated in the peripheral blood mononuclear cells (PBMCs) of patients with bronchial asthma. In addition, levels of TF and TSP-1 in the sera were up-regulated in patients with asthma compared with healthy controls. TIPE2 expression was negatively correlated with TF in the PBMCs and sera and was negatively correlated with TSP-1 levels in the sera of patients with bronchial asthma. The results of the current study indicated that anti-inflammatory TIPE2 levels are associated with levels of the coagulation substances TF and TSP-1. However, further studies are required to determine whether TIPE2 participates in the pathogenesis of asthma by interacting with the coagulation substances TF and TSP-1.

Regulating effect of glycyrrhetinic acid on bronchial asthma smooth muscle proliferation and apoptosis as well as inflammatory factor expression through ERK1/2 signaling pathway

OBJECTIVE

To study the influence of glycyrrhetinic acid (GA) on bronchial asthma (BA) smooth muscle proliferation and apoptosis as well as inflammatory factor expression and its molecular mechanism.

METHODS

Male SD guinea pigs were selected and made into asthma models, bronchial asthma smooth muscle cells were cultured and divided into BA group, GA group and GA + LM group that were treated with serum-free RPMI1640 culture medium, serum-free RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid, serum-free RPMI1640 culture medium containing 50 ng/mL glycyrrhetinic acid and 100 ng/mL LM22B-10 respectively; normal guinea pigs were collected and bronchial smooth muscle cells were cultured as control group. The cell proliferation activity as well as the expression of proliferation and apoptosis genes, inflammatory factors and p-ERK1/2 was determined.

RESULTS

Proliferation activity value and mRNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in BA group were significantly higher than those of control group while mRNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly lower than that of control group (P < 0.05); proliferation activity value and mRNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40, protein expression of p-ERK1/2 of airway smooth muscle cell in GA group were significantly lower than those of BA group (P < 0.05) while the mRNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly higher than those of BA group (P < 0.05); proliferation activity value and mRNA expression of Bcl-2, TNF-α, IL-4, IL-6, YKL-40 of airway smooth muscle cell in GA + LM group were significantly higher than those of GA group (P < 0.05) while mRNA expression levels of Bax, caspase-9 as well as caspase-3 were significantly lower that of GA group (P < 0.05).

CONCLUSION

GA can inhibit the proliferation of bronchial smooth muscle cells and reduce the expression of inflammatory factors by inhibiting the phosphorylation of ERK1/2.

p300 and C/EBPβ-regulated IKKβ expression are involved in thrombin-induced IL-8/CXCL8 expression in human lung epithelial cells

Asthma and chronic obstructive pulmonary disease (COPD) are common chronic lung inflammatory diseases. Thrombin and interleukin (IL)-8/C-X-C chemokine ligand 8 (CXCL8) play critical roles in lung inflammation. Our previous study showed that c-Src-dependent IκB kinase (IKK)/IκBα/nuclear factor (NF)-κB and mitogen-activated protein kinase kinase kinase 1 (MEKK1)/extracellular signal-regulated kinase (ERK)/ribosomal S6 protein kinase (RSK)-dependent CAAT/enhancer-binding protein β (C/EBPβ) activation are involved in thrombin-induced IL-8/CXCL8 expression in human lung epithelial cells. In this study, we aimed to investigate the roles of p300 and C/EBPβ-reliant IKKβ expression in thrombin-induced IL-8/CXCL8 expression. Thrombin-induced increases in IL-8/CXCL8-luciferase activity and IL-8/CXCL8 release were inhibited by p300 small interfering (siRNA). Thrombin-caused histone H3 acetylation was attenuated by p300 siRNA. Stimulation of cells with thrombin for 12h resulted in increases in IKKβ expression and phosphorylation in human lung epithelial cells. However, thrombin did not affect p65 expression. Moreover, 12h of thrombin stimulation produced increases in IKKβ expression and phosphorylation, and IκBα phosphorylation, which were inhibited by C/EBPβ siRNA. Finally, treatment of cells with thrombin caused increases in p300 and C/EBPβ complex formation, p65 and C/EBPβ complex formation, and recruitment of p300, p65, and C/EBPβ to the IL-8/CXCL8 promoter. These results imply that p300-dependent histone H3 acetylation and C/EBPβ-regulated IKKβ expression contribute to thrombin-induced IL-8/CXCL8 expression in human lung epithelial cells. Results of this study will help clarify C/EBPβ signaling pathways involved in thrombin-induced IL-8/CXCL8 expression in human lung epithelial cells.