ABSTRACT
Allergic airway inflammation is one of the primary features of allergic asthma. Interleukin-33 (IL-33) is recognized as a key pro-inflammatory cytokine that mediates allergic airway inflammation, and its expression is elevated in this condition, but little is known about the regulatory mechanisms underlying IL-33 induction. Here, we show that the RNA binding protein Mex-3B plays a critical role in the induction of IL-33 in the development of allergic airway inflammation. We generated Mex3b(-/-) mice and found that they develop significantly less airway inflammation than wild-type mice due to reduced induction of IL-33. Furthermore, we show that Mex-3B directly upregulates IL-33 expression by inhibiting miR-487b-3p-mediated repression of IL-33. Moreover, we show that inhalation of an antisense oligonucleotide targeting Mex-3B suppresses allergic airway inflammation. Our data identify a signaling pathway that post-transcriptionally regulates IL-33 expression and suggest that Mex-3B could be a promising molecular target for the treatment of allergic asthma.
Subject(s)
Bronchial Hyperreactivity/therapy , Epithelial Cells/drug effects , Interleukin-33/immunology , MicroRNAs/immunology , Oligonucleotides, Antisense/pharmacology , RNA-Binding Proteins/antagonists & inhibitors , Animals , Base Sequence , Bronchial Hyperreactivity/chemically induced , Bronchial Hyperreactivity/immunology , Bronchial Hyperreactivity/pathology , Epithelial Cells/immunology , Epithelial Cells/pathology , Gene Expression Regulation , Humans , Interleukin-33/genetics , Killer Cells, Natural/drug effects , Killer Cells, Natural/immunology , Killer Cells, Natural/pathology , Mast Cells/drug effects , Mast Cells/immunology , Mast Cells/pathology , Mice , Mice, Inbred BALB C , Mice, Knockout , MicroRNAs/genetics , Nucleic Acid Conformation , Oligonucleotides, Antisense/genetics , Oligonucleotides, Antisense/metabolism , Ovalbumin , Pulmonary Alveoli/drug effects , Pulmonary Alveoli/immunology , Pulmonary Alveoli/pathology , RNA-Binding Proteins/genetics , RNA-Binding Proteins/immunology , Respiratory Mucosa/drug effects , Respiratory Mucosa/immunology , Respiratory Mucosa/pathology , Signal Transduction , Th2 Cells/drug effects , Th2 Cells/immunology , Th2 Cells/pathologyABSTRACT
Malic enzyme prepared and purified from Brevundimonas diminuta IFO13182 catalyzed the decarboxylation reaction of malate to pyruvate and CO2 using NAD+ as the coenzyme, and the reverse reaction was used in the present study for L-malic acid production with fixation of HCO3(-) as a model compound for carbon source. The L-malic acid production was based on electrochemical regeneration of NADH on a carbon plate electrode modified by layer-by-layer adsorption of polymer-bound mediator (Alginic acid bound viologen derivative, Alg-V), polymer-bound coenzyme (Alginic acid bound NAD+, Alg-NAD+), and lipoamide dehydrogenase (LipDH). Electrochemical reduction of immobilized NAD+ catalyzed by LipDH in a multilayer film was achieved, and the L-malic acid production with HCO3(-) fixation system with layer-by-layer immobilization of Alg-V/LipDH/Alg-NAD+/malic enzyme multilayer film on the electrode gave an L-malic acid production of nearly 11.9 mmol and an HCO3(-) fixation rate of nearly 47.4% in a buffer containing only KHCO3 and pyruvic acid potassium salt, using a cation exchange membrane. The total turnover number of NADH within 48 h was about 19,000, which suggests that efficient NADH regeneration and fast electron transfer were achieved within the multilayer film, and that the modified electrode is a potential method for the fixation of HCO3(-) without addition of free coenzyme.
Subject(s)
Bicarbonates/chemistry , Electrodes , Malates/chemistry , Adsorption , Alginates/chemistry , Buffers , Carbon Dioxide/chemistry , Catalysis , Cations , Dihydrolipoamide Dehydrogenase/chemistry , Electrochemistry/methods , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , NAD/chemistry , Polymers/chemistry , Regeneration , Time FactorsABSTRACT
Malic enzyme [L-malate: NAD(P)(+) oxidoreductase (EC 1.1.1.39)] catalyzes the oxidative decarboxylation of L-malic acid to produce pyruvic acid using the oxidized form of NAD(P) (NAD(P)(+)). We used a reverse reaction of the malic enzyme of Pseudomonas diminuta IFO 13182 for HCO(3)(-) fixation into pyruvic acid to produce L-malic acid with coenzyme (NADH) generation. Glucose-6-phosphate dehydrogenase (EC1.1.1.49) of Leuconostoc mesenteroides was suitable for coenzyme regeneration. Optimum conditions for the carboxylation of pyruvic acid were examined, including pyruvic acid, NAD(+), and both malic enzyme and glucose-6-phosphate dehydrogenase concentrations. Under optimal conditions, the ratio of HCO(3)(-) and pyruvic acid to malic acid was about 38% after 24 h of incubation at 30 degrees C, and the concentration of the accumulated L-malic acid in the reaction mixture was 38 mM. The malic enzyme reverse reaction was also carried out by the conjugated redox enzyme reaction with water-soluble polymer-bound NAD(+).
