S100A8/9 modulates perturbation and glycolysis of macrophages in allergic asthma mice.

Background: Allergic asthma is the most prevalent asthma phenotype and is associated with the disorders of immune cells and glycolysis. Macrophages are the most common type of immune cells in the lungs. Calprotectin (S100A8 and S100A9) are two pro-inflammatory molecules that target the Toll-like receptor 4 (TLR4) and are substantially increased in the serum of patients with severe asthma. This study aimed to determine the effects of S100A8/A9 on macrophage polarization and glycolysis associated with allergic asthma. Methods: To better understand the roles of S100A8 and S100A9 in the pathogenesis of allergic asthma, we used ovalbumin (OVA)-induced MH-S cells, and OVA-sensitized and challenged mouse models (wild-type male BALB/c mice). Enzyme-linked immunosorbent assay, quantitative real-time polymerase chain reaction, flow cytometry, hematoxylin-eosin staining, and western blotting were performed. The glycolysis inhibitor 3-bromopyruvate (3-BP) was used to observe changes in glycolysis in mice. Results: We found knockdown of S100A8 or S100A9 in OVA-induced MH-S cells inhibited inflammatory cytokines, macrophage polarization biomarker expression, and pyroptosis cell proportion, but increased anti-inflammatory cytokine interleukin (IL)-10 mRNA; also, glycolysis was inhibited, as evidenced by decreased lactate and key enzyme expression; especially, knockdown of S100A8 or S100A9 inhibited the activity of TLR4/myeloid differentiation primary response gene 88 (MyD88)/Nuclear factor kappa-B (NF-κB) signaling pathway. Intervention with lipopolysaccharides (LPS) abolished the beneficial effects of S100A8 and S100A9 knockdown. The observation of OVA-sensitized and challenged mice showed that S100A8 or S100A9 knockdown promoted respiratory function, improved lung injury, and inhibited inflammation; knockdown of S100A8 or S100A9 also suppressed macrophage polarization, glycolysis levels, and activation of the TLR4/MyD88/NF-κB signaling pathway in the lung. Conversely, S100A9 overexpression exacerbated lung injury and inflammation, promoting macrophage polarization and glycolysis, which were antagonized by the glycolysis inhibitor 3-BP. Conclusion: S100A8 and S100A9 play critical roles in allergic asthma pathogenesis by promoting macrophage perturbation and glycolysis through the TLR4/MyD88/NF-κB signaling pathway. Inhibition of S100A8 and S100A9 may be a potential therapeutic strategy for allergic asthma.

Less invasive surfactant administration versus endotracheal surfactant instillation followed by limited peak pressure ventilation in preterm infants with respiratory distress syndrome in China: study protocol for a randomized controlled trial.

BACKGROUND: Less invasive surfactant administration (LISA) is a way of giving surfactant without endotracheal intubation and has shown to be promising in reducing the incidence of bronchopulmonary dysplasia (BPD) in preterm infants. However, the mechanism underlying its beneficial effect and variations in the technique of administration may prevent its widespread use. This trial aims to evaluate the effects of two methods of surfactant administration, LISA or endotracheal surfactant administration followed by low peak pressure (LPPSA) ventilation, in preterm infants with respiratory distress syndrome (RDS). METHODS: The LISA Or Low Peak Pressure trial is to be conducted in 14 tertiary neonatal intensive care units in China. A total of 600 preterm infants born with gestational age between 250/7 and 316/7 weeks and with a primary diagnosis of RDS will be involved in the study. Infants will be randomized to the LISA or LPPSA group when surfactant therapy is indicated. Primary outcomes include mortality, severity of bronchopulmonary dysplasia at 36 weeks of postmenstrual age (PMA), and mechanical ventilation (MV) in the first 72 h of life. Secondary outcomes include the days of MV, duration of all sorts of non-invasive respiratory support, fraction of inspired oxygen, oxygen saturation before and after surfactant administration, and time required to perform the procedure for surfactant administration. The incidence of comorbidities, including retinopathy of prematurity (ROP), necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH), hemodynamically significant patent ductus arteriosus (hsPDA), pneumothorax, and massive pulmonary hemorrhage within 48 h of surfactant administration, and the failure rates of each technique will be determined. DISCUSSION: Data from recent systematic review and meta-analysis have suggested a possible improvement in outcomes of preterm infants with RDS by the LISA technique. However, robust evidence is lacking. Why LISA plays a potential role in reducing respiratory morbidity, mainly BPD in preterm infants, remains unclear. The possible explanations are the active and uninterrupted delivery of continuous positive airway pressure during the LISA procedure and the avoidance of complications caused by intubation and relatively high pressure/volume ventilation following surfactant administration. We hypothesized that LISA's effectiveness lies mainly in avoiding relatively high-pressure positive ventilation immediately following surfactant administration. Thus, this multicenter randomized controlled trial will focus on issues of endotracheal intubation and the pressure/volume used during conventional surfactant administration. The effectiveness, safety and comorbidities of preterm infants following LISA or LPPSA will be evaluated. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR1900020970. Registered on 23 January 2019.

Long noncoding RNA MALAT1 sponges miR-129-5p to regulate the development of bronchopulmonary dysplasia by increasing the expression of HMGB1.

OBJECTIVE: To explore the function and mechanism of long noncoding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in bronchopulmonary dysplasia. METHODS: Alveolar epithelial cell line BEAS-2B was used as the cell model. The role of MALAT1 and microRNA miR-129-5p in regulating cellular viability and migration were examined by using the CCK-8 and Transwell assays, respectively, in vitro. The luciferase reporter assay and real-time (RT)-PCR were performed to confirm that miR-129-5p was a target of MALAT1. ELISA was conducted to validate MALAT1 and show that miR-129-5p regulated the gene encoding high-mobility group protein 1 (HMGB1). RESULTS: Overexpression of MALAT1 significantly promoted cellular viability, whereas miR-129-5p had the opposite effect. miR-129-5p was shown to be a target of MALAT1, and HMGB1 could be upregulated by MALAT1 overexpression or miR-129-5p inhibition. CONCLUSION: MALAT1 reduced the expression of miR-129-5p, promoting the viability of cells and blocking the development of bronchopulmonary dysplasia. In addition, MALAT1 increased the expression of HMGB1, which contributed to inflammation as the disease progressed.