Plasma based targeted metabolomic analysis reveals alterations of phosphatidylcholines and oxidative stress markers in guinea pig model of allergic asthma

The First In Vivo Study Shows That Gyrophoric Acid Changes Behavior of Healthy Laboratory Rats

Gyrophoric acid (GA), a lichen secondary metabolite, has attracted more attention during the last years because of its potential biological effects. Until now, its effect in vivo has not yet been demonstrated. The aim of our study was to evaluate the basic physicochemical and pharmacokinetic properties of GA, which are directly associated with its biological activities. The stability of the GA in various pH was assessed by conducting repeated UV-VIS spectral measurements. Microsomal stability in rat liver microsomes was performed using Ultra-Performance LC/MS. Binding to human serum albumin (HSA) was assessed using synchronous fluorescence spectra, and molecular docking analysis was used to reveal the binding site of GA to HSA. In the in vivo experiment, 24 Sprague-Dawley rats (Velaz, Únetice, Czech Republic) were used. The animals were divided as follows. The first group (n = 6) included healthy males as control intact rats (♂INT), and the second group (n = 6) included healthy females as controls (♀INT). Groups three and four (♂GA/n = 6 and ♀GA/n = 6) consisted of animals with daily administered GA (10 mg/kg body weight) in an ethanol-water solution per os for a one-month period. We found that GA remained stable under various pH and temperature conditions. It bonded to human serum albumin with the binding constant 1.788 × 106 dm3mol-1 to reach the target tissue via this mechanism. In vivo, GA did not influence body mass gain, food, or fluid intake during the experiment. No liver toxicity was observed. However, GA increased the rearing frequency in behavioral tests (p < 0.01) and center crossings in the elevated plus-maze (p < 0.01 and p < 0.001, respectively). In addition, the time spent in the open arm was prolonged (p < 0.01 and p < 0.001, respectively). Notably, GA was able to pass through the blood-brain barrier, indicating its ability to permeate into the brain and to stimulate neurogenesis in the hilus and subgranular zone of the hippocampus. These observations highlight the potential role of GA in influencing brain function and neurogenesis.

Metabolomics in Animal Models of Bronchial Asthma and Its Translational Importance for Clinics

Bronchial asthma is an extremely heterogenous chronic respiratory disorder with several distinct endotypes and phenotypes. These subtypes differ not only in the pathophysiological changes and/or clinical features but also in their response to the treatment. Therefore, precise diagnostics represent a fundamental condition for effective therapy. In the diagnostic process, metabolomic approaches have been increasingly used, providing detailed information on the metabolic alterations associated with human asthma. Further information is brought by metabolomic analysis of samples obtained from animal models. This article summarizes the current knowledge on metabolomic changes in human and animal studies of asthma and reveals that alterations in lipid metabolism, amino acid metabolism, purine metabolism, glycolysis and the tricarboxylic acid cycle found in the animal studies resemble, to a large extent, the changes found in human patients with asthma. The findings indicate that, despite the limitations of animal modeling in asthma, pre-clinical testing and metabolomic analysis of animal samples may, together with metabolomic analysis of human samples, contribute to a novel way of personalized treatment of asthma patients.

Sex differences in plasma metabolites in a guinea pig model of allergic asthma

Sex seems to be a contributing factor in the pathogenesis of bronchial asthma. This study aimed to find sex-related differences in metabolome measured by hydrogen-1 nuclear magnetic resonance ((1)H NMR) spectroscopy in healthy and ovalbumin (OVA)-sensitized guinea pigs. Adult male and female animals were divided into controls and OVA-sensitized groups. OVA-sensitization was performed by OVA systemic and inhalational administration within 14 days; on day 15, animals were killed by anesthetic overdose followed by exsanguination. Blood was taken and differential white blood cell count was measured. Left lung was saline-lavaged and differential cell count in the bronchoalveolar lavage fluid (BALF) was measured. After blood centrifugation, plasma was processed for (1)H NMR analysis. Metabolomic data was evaluated by principal component analysis (PCA). Eosinophil counts elevated in the BALF confirming eosinophil-mediated inflammation in OVA-sensitized animals of both sexes. Sex differences for lactate, glucose, and citrate were found in controls, where these parameters were lower in males than in females. In OVA-sensitized males higher glucose and lower pyruvate were found compared to controls. OVA-sensitized females showed lower lactate, glucose, alanine, 3-hydroxy-butyrate, creatine, pyruvate, and succinate concentrations compared to controls. In OVA-sensitized animals, lactate concentration was lower in males. Data from females (healthy and OVA-sensitized) were generally more heterogeneous. Significant sex differences in plasma concentrations of metabolites were found in both healthy and OVA-sensitized animals suggesting that sex may influence the metabolism and may thereby contribute to different clinical picture of asthma in males and females.

BRD4 facilitates osteogenic differentiation of human bone marrow mesenchymal stem cells through WNT4/NF-κB pathway

BACKGROUND

Human bone marrow mesenchymal stem cells (hBMSCs) are a major source of osteoblast precursor cells and are directly involved in osteoporosis (OP) progression. Bromodomain-containing protein 4 (BRD4) is an important regulator for osteogenic differentiation. Therefore, its role and mechanism in osteogenic differentiation process deserve further investigation.

METHODS

hBMSCs osteogenic differentiation was evaluated by flow cytometry, alkaline phosphatase assay and alizarin red staining. Western blot was used to test osteogenic differentiation-related proteins, BRD4 protein, WNT family members-4 (WNT4)/NF-κB-related proteins, and glycolysis-related proteins. Metabolomics techniques were used to detect metabolite changes and metabolic pathways. BRD4 and WNT4 mRNA levels were determined using quantitative real-time PCR. Dual-luciferase reporter assay and chromatin immunoprecipitation assay were performed to detect BRD4 and WNT4 interaction. Glycolysis ability was assessed by testing glucose uptake, lactic acid production, and ATP levels.

RESULTS

After successful induction of osteogenic differentiation, the expression of BRD4 was increased significantly. BRD4 knockdown inhibited hBMSCs osteogenic differentiation. Metabolomics analysis showed that BRD4 expression was related to glucose metabolism in osteogenic differentiation. Moreover, BRD4 could directly bind to the promoter of the WNT4 gene. Further experiments confirmed that recombinant WNT4 reversed the inhibition effect of BRD4 knockdown on glycolysis, and NF-κB inhibitors (Bardoxolone Methyl) overturned the suppressive effect of BRD4 knockdown on hBMSCs osteogenic differentiation.

CONCLUSION

BRD4 promoted hBMSCs osteogenic differentiation by inhibiting NF-κB pathway via enhancing WNT4 expression.

β-Hydroxybutyric acid upregulated by Suhuang antitussive capsule ameliorates cough variant asthma through GSK3β/AMPK-Nrf2 signal axis

ETHNOPHARMACOLOGICAL RELEVANCE

Cough variant asthma (CVA) is a chronic inflammatory disease characterized by cough as the main symptom. Suhuang antitussive capsule (Suhuang), one of traditional Chinese patent medicines, mainly treats CVA clinically. Previous studies have shown that Suhuang significantly improved CVA, post-infectious cough (PIC), sputum obstruction and airway remodeling. However, the effect of Suhuang on ovalbumin-induced (OVA-induced) metabolic abnormalities in CVA is unknown.

AIM OF THE STUDY

This study aimed to identify potential metabolites associated with efficacy of Suhuang in the treatment of CVA, and determined how Suhuang regulates metabolites, and differential metabolites reduce inflammation and oxidative stress.

MATERIALS AND METHODS

Rats were given 1 mg OVA/100 mg aluminum hydroxide in the 1st and 7th days by intraperitoneal injection and challenged by atomizing inhalation of 1% OVA saline solution after two weeks to establish the CVA model. Rats were intragastrically (i.g.) administrated with Suhuang at 1.4 g/kg and β-hydroxybutyric acid (β-HB) were given with different concentrations (87.5 and 175 mg/kg/day) by intraperitoneal injection for 2 weeks. After 26 days, GC-MS-based metabolomic approach was applied to observe metabolic changes and search differential metabolites. The number of coughs, coughs latencies, enzyme-linked immunosorbent assay (ELISA), histological analysis and quantitative-polymerase chain reaction (Q-PCR) were used to investigate the effects of Suhuang. Then β-HB on CVA rats, NLRP3 inflammasome and GSK3β/AMPK/Nrf2 signalling pathway were detected by western blotting.

RESULTS

The results showed that Suhuang treatment significantly enhanced the serum level of β-HB. Interestingly, exposure to exogenous β-HB was also protective against OVA-induced CVA. β-HB significantly reduced the number of coughs and lengthened coughs latencies, improved lung injury, reduced the secretion of various cytokines, and directly inhibited the NLRP3 inflammasome. In addition, β-HB increased the nuclear accumulation of Nrf2 by activating the GSK3β/AMPK signaling axis, and then inactivating the NF-κB signaling pathway, effectively protecting OVA-induced CVA from oxidative stress and inflammation.

CONCLUSIONS

The results of this study shows that β-HB can reduce inflammation and oxidative stress, the increased production of β-HB in serum might be the crucial factor for Suhuang to exert its effect in the treatment of CVA.

The Combination of Bioinformatics Analysis and Untargeted Metabolomics Reveals Potential Biomarkers and Key Metabolic Pathways in Asthma

Asthma is a complex chronic airway inflammatory disease that seriously impacts patients' quality of life. As a novel approach to exploring the pathogenesis of diseases, metabolomics provides the potential to identify biomarkers of asthma host susceptibility and elucidate biological pathways. The aim of this study was to screen potential biomarkers and biological pathways so as to provide possible pharmacological therapeutic targets for asthma. In the present study, we merged the differentially expressed genes (DEGs) of asthma in the GEO database with the metabolic genes obtained by Genecard for bioinformatics analysis and successfully screened out the metabolism-related hub genes (HIF1A, OCRL, NNMT, and PER1). Then, untargeted metabolic techniques were utilized to reveal HDM-induced metabolite alterations in 16HBE cells. A total of 45 significant differential metabolites and 5 differential metabolic pathways between the control group and HDM group were identified based on the OPLS-DA model. Finally, three key metabolic pathways, including glycerophospholipid metabolism, galactose metabolism, and alanine, aspartate, and glutamate metabolism, were screened through the integrated analysis of bioinformatics data and untargeted metabolomics data. Taken together, these findings provide valuable insights into the pathophysiology and targeted therapy of asthma and lay a foundation for further research.

Longitudinal associations between metabolites and long-term exposure to ambient air pollution: Results from the KORA cohort study

BACKGROUND

Long-term exposure to air pollution has been associated with cardiopulmonary diseases, while the underlying mechanisms remain unclear.

OBJECTIVES

To investigate changes in serum metabolites associated with long-term exposure to air pollution and explore the susceptibility characteristics.

METHODS

We used data from the German population-based Cooperative Health Research in the Region of Augsburg (KORA) S4 survey (1999-2001) and two follow-up examinations (F4: 2006-08 and FF4: 2013-14). Mass-spectrometry-based targeted metabolomics was used to quantify metabolites among serum samples. Only participants with repeated metabolites measurements were included in the current analysis. Land-use regression (LUR) models were used to estimate annual average concentrations of ultrafine particles, particulate matter (PM) with an aerodynamic diameter less than 10 μm (PM₁₀), coarse particles (PM_coarse), fine particles, PM_2.5 absorbance (a proxy of elemental carbon related to traffic exhaust, PM_2.5abs), nitrogen oxides (NO₂, NO_x), and ozone at individuals' residences. We applied confounder-adjusted mixed-effects regression models to examine the associations between long-term exposure to air pollution and metabolites.

RESULTS

Among 9,620 observations from 4,261 KORA participants, we included 5,772 (60.0%) observations from 2,583 (60.6%) participants in this analysis. Out of 108 metabolites that passed stringent quality control across three study points in time, we identified nine significant negative associations between phosphatidylcholines (PCs) and ambient pollutants at a Benjamini-Hochberg false discovery rate (FDR) corrected p-value < 0.05. The strongest association was seen for an increase of 0.27 μg/m³ (interquartile range) in PM_2.5abs and decreased phosphatidylcholine acyl-alkyl C36:3 (PC ae C36:3) concentrations [percent change in the geometric mean: -2.5% (95% confidence interval: -3.6%, -1.5%)].

CONCLUSIONS

Our study suggested that long-term exposure to air pollution is associated with metabolic alterations, particularly in PCs with unsaturated long-chain fatty acids. These findings might provide new insights into potential mechanisms for air pollution-related adverse outcomes.

Integrative lipidomic features identify plasma lipid signatures in chronic urticaria

Chronic urticaria (CU) is a chronic inflammatory skin disease mainly mediated by mast cells. Lipids exert essential functions in biological processes; however, the role of lipids in CU remains unclear. Nontargeted lipidomics was performed to investigate the differential lipid profiles between CU patients and healthy control (HC) subjects. Functional validation studies were performed in vitro and in vivo including β-hexosaminidase release examination from mast cells and passive cutaneous anaphylaxis (PCA) mouse model. We detected dramatically altered glycerophospholipids in CU patients compared with HCs. Phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG) were increased, while phosphatidylcholine (PC) was reduced in CU patients. The reduction in PC was related to a high weekly urticaria activity score (UAS7), while PS was positively associated with the dermatology life quality index (DLQI). We also identified the differential lipid profiles between chronic spontaneous urticaria (CSU), symptomatic dermographism (SD), and CSU coexist with SD. CU patients were classified into two subtypes (subtype 1 and subtype 2) based on consensus clustering of lipid profiling. Compared with patients in subtype 2, patients in subtype 1 had elevated levels of PC (18:0e/18:2) and PE (38:2), and lower urticaria control test (UCT) scores indicated worse clinical efficiency of secondary generation H1 antihistamines treatment. Importantly, we found that supplementation with PC could attenuate IgE-induced immune responses in mast cells. In general, We described the landscape of plasma lipid alterations in CU patients and provided novel insights into the role of PC in mast cells.

Biochemical Properties of Atranorin-Induced Behavioral and Systematic Changes of Laboratory Rats

Atranorin (ATR) is a secondary metabolite of lichens. While previous studies investigated the effects of this substance predominantly in an in vitro environment, in our study we investigated the basic physicochemical properties, the binding affinity to human serum albumin (HSA), basic pharmacokinetics, and, mainly, on the systematic effects of ATR in vivo. Sporadic studies describe its effects during, predominantly, cancer. This project is original in terms of testing the efficacy of ATR on a healthy organism, where we can possibly attribute negative effects directly to ATR and not to the disease. For the experiment, 24 Sprague Dawley rats (Velaz, Únetice, Czech Republic) were used. The animals were divided into four groups. The first group (n = 6) included healthy males as control intact rats (♂INT) and the second group (n = 6) included healthy females as control intact rats (♀INT). Groups three and four (♂ATR/n = 6 and ♀ATR/n = 6) consisted of animals with daily administered ATR (10mg/kg body weight) in an ethanol-water solution per os for a one-month period. Our results demonstrate that ATR binds to HSA near the binding site TRP214 and acts on a systemic level. ATR caused mild anemia during the treatment. However, based on the levels of hepatic enzymes in the blood (ALT, ALP, or bilirubin levels), thiobarbituric acid reactive substances (TBARS), or liver histology, no impact on liver was recorded. Significantly increased creatinine and lactate dehydrogenase levels together with increased defecation activity during behavioral testing may indicate the anabolic effect of ATR in skeletal muscles. Interestingly, ATR changed some forms of behavior. ATR at a dose of 10 mg/kg body weight is non-toxic and, therefore, could be used in further research.

Plasma Lipid Profiling Identifies Phosphatidylcholine 34:3 and Triglyceride 52:3 as Potential Markers Associated with Disease Severity and Oxidative Status in Chronic Obstructive Pulmonary Disease

PURPOSE

To identify plasma alterations in lipid species in patients with chronic obstructive pulmonary disease (COPD), as well as, relationships with smoking status, oxidative and inflammatory markers.

METHODS

Plasma was obtained from 100 patients with COPD and 120 healthy controls. Pulmonary function was assessed by plethysmography. Serum levels of IL-6 and TNF-α were determined by ELISA. Oxidative stress parameters were measured using standard methods. Lipids were extracted then analyzed by Matrix-Assisted Laser Desorption and Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-TOF-MS).

RESULTS

More than 40 lipid compounds were identified within plasma samples. Among these 19 lipid species including plasmalogens (PC O-), phosphatidylcholines (PC), and triglycerides (TG) were significantly altered in COPD. A decreased expression of PC O- (36:1, 36:2, 36:3, 36:4, 38:4, 38:5) species was found in patients with different severities compared to healthy controls. There was also a decrease in PC (34:3, 36:0, 36:4, 36:5, 40:6, 40:7) species in COPD patients. PC (34:3) levels were positively correlated with disease progression and pulmonary function decline (forced expiratory volume in 1 s (FEV₁)) (r = 0.84, p < 0.001) and inversely correlated with thiobarbituric acid-reactive substances (TBARS) (r = - 0.77, p < 0.001). TG (50:0, 50:1, 52:1, 52:2, 52:3, 52:4, 54:4) species were altered in COPD patients and in those with advanced disease stages. Significant correlations between FEV₁, TBARS, peroxynitrite, and TG (52:3) were found among COPD patients (r = - 0.69; r = 0.86; r = 0.77, p < 0.001, respectively).

CONCLUSION

PC (34:3) and TG (52:3) could be potential lipid signatures of COPD that correlate with altered pulmonary function and oxidative status.

Understanding uncontrolled severe allergic asthma by integration of omic and clinical data

BACKGROUND

Asthma is a complex, multifactorial disease often linked with sensitization to house dust mites (HDM). There is a subset of patients that does not respond to available treatments, who present a higher number of exacerbations and a worse quality of life. To understand the mechanisms of poor asthma control and disease severity, we aim to elucidate the metabolic and immunologic routes underlying this specific phenotype and the associated clinical features.

METHODS

Eighty-seven patients with a clinical history of asthma were recruited and stratified in 4 groups according to their response to treatment: corticosteroid-controlled (ICS), immunotherapy-controlled (IT), biologicals-controlled (BIO) or uncontrolled (UC). Serum samples were analysed by metabolomics and proteomics; and classifiers were built using machine-learning algorithms.

RESULTS

Metabolomic analysis showed that ICS and UC groups cluster separately from one another and display the highest number of significantly different metabolites among all comparisons. Metabolite identification and pathway enrichment analysis highlighted increased levels of lysophospholipids related to inflammatory pathways in the UC patients. Likewise, 8 proteins were either upregulated (CCL13, ARG1, IL15 and TNFRSF12A) or downregulated (sCD4, CCL19 and IFNγ) in UC patients compared to ICS, suggesting a significant activation of T cells in these patients. Finally, the machine-learning model built including metabolomic and clinical data was able to classify the patients with an 87.5% accuracy.

CONCLUSIONS

UC patients display a unique fingerprint characterized by inflammatory-related metabolites and proteins, suggesting a pro-inflammatory environment. Moreover, the integration of clinical and experimental data led to a deeper understanding of the mechanisms underlying UC phenotype.

Essential Protective Role of Catalytically Active Antibodies (Abzymes) with Redox Antioxidant Functions in Animals and Humans

During the life of aerobic organisms, the oxygen resulting from numerous reactions is converted into reactive oxygen species (ROS). Many ROS are dangerous due to their high reactivity; they are strong oxidants, and react with various cell components, leading to their damage. To protect against ROS overproduction, enzymatic and non-enzymatic systems are evolved in aerobic cells. Several known non-enzymatic antioxidants have a relatively low specific antioxidant activity. Superoxide dismutases, catalase, glutathione peroxidase, glutathione S-transferase, thioredoxin, and the peroxiredoxin families are the most important enzyme antioxidants. Artificial antibodies catalyzing redox reactions using different approaches have been created. During the past several decades, it has been shown that the blood and various biological fluids of humans and animals contain natural antibodies that catalyze different redox reactions, such as classical enzymes. This review, for the first time, summarizes data on existing non-enzymatic antioxidants, canonical enzymes, and artificial or natural antibodies (abzymes) with redox functions. Comparing abzymes with superoxide dismutase, catalase, peroxide-dependent peroxidase, and H₂O₂-independent oxidoreductase activities with the same activities as classical enzymes was carried out. The features of abzymes with the redox activities are described, including their exceptional diversity in the optimal pH values, dependency and independence on various metal ions, and the reaction rate constants for healthy donors and patients with different autoimmune diseases. The entire body of evidence indicates that abzymes with redox antioxidant activities existing in the blood for a long time compared to enzymes are an essential part of the protection system of humans and animals from oxidative stress.

Detection of serum phospholipids by microchannel-integrated black phosphorus-assisted laser desorption/ionization mass spectrometry

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been widely applied in the analysis of phospholipids in biological samples. However, it remains a challenge to improve the sensitivity and reproducibility and to control the background noise of matrices. In this study, black phosphorus nanomaterial was used as the matrix of MALDI-MS, and microchannel technique was combined. This microchannel-integrated black phosphorus-assisted laser desorption/ionization (BPALDI) MS approach can effectively detect a variety of lipids with a small amount of sample, and has high sensitivity for phosphatidylcholines (PC) and lysophosphatidylcholines (LPC) with a detection limit of 0.2 μg/mL. Compared with traditional matrices, BPALDI-MS has the advantages of high sensitivity, good reproducibility, and high salt tolerance. This method was successfully applied in the detection of serum PC/LPC ratios in children patients with asthma or bronchopneumonia. This work provides a novel application of black phosphorus matrix and microchannel technique, and gives new insights into method development of rapid screening and identification of disease indicators in biological fluids.

Urinary metabotype of severe asthma evidences decreased carnitine metabolism independent of oral corticosteroid treatment in the U-BIOPRED study

INTRODUCTION

Asthma is a heterogeneous disease with poorly defined phenotypes. Severe asthmatics often receive multiple treatments including oral corticosteroids (OCS). Treatment may modify the observed metabotype, rendering it challenging to investigate underlying disease mechanisms. Here, we aimed to identify dysregulated metabolic processes in relation to asthma severity and medication.

METHODS

Baseline urine was collected prospectively from healthy participants (n=100), mild-to-moderate asthmatics (n=87) and severe asthmatics (n=418) in the cross-sectional U-BIOPRED cohort; 12-18-month longitudinal samples were collected from severe asthmatics (n=305). Metabolomics data were acquired using high-resolution mass spectrometry and analysed using univariate and multivariate methods.

RESULTS

Ninety metabolites were identified, with 40 significantly altered (p<0.05, FDR<0.05) in severe asthma and 23 by OCS use. Multivariate modelling showed that observed metabotypes in healthy participants and mild-to-moderate asthmatics differed significantly from severe asthmatics (p=2.6×10^-20), OCS-treated asthmatics differed significantly from non-treated (p=9.5×10^-4), and longitudinal metabotypes demonstrated temporal stability. Carnitine levels evidenced the strongest OCS-independent decrease in severe asthma. Reduced carnitine levels were associated with mitochondrial dysfunction via decreases in pathway enrichment scores of fatty acid metabolism and reduced expression of the carnitine transporter SLC22A5 in sputum and bronchial brushings.

CONCLUSIONS

This is the first large-scale study to delineate disease- and OCS-associated metabolic differences in asthma. The widespread associations with different therapies upon the observed metabotypes demonstrate the necessity to evaluate potential modulating effects on a treatment- and metabolite-specific basis. Altered carnitine metabolism is a potentially actionable therapeutic target that is independent of OCS treatment, highlighting the role of mitochondrial dysfunction in severe asthma.

Plasma characteristic metabolites of pediatric community-acquired pneumonia in traditional Chinese medicine syndrome differentiation

Community-acquired pneumonia (CAP) is the leading cause of lower respiratory tract infections in children. Heat syndrome (HS) and cold syndrome (CS) are two main syndrome types of pediatric CAP in traditional Chinese medicine (TCM). This study aimed to identify plasma metabolic profiles in pediatric CAP and to further select potential biomarkers to distinguish between HS and CS. An ultra-performance liquid chromatography coupled with linear ion trap quadrupole-orbitrap mass spectrometry method was applied to plasma samples of 296 patients and 55 healthy controls (HC). The samples were divided into the discovery group (n = 213, HS = 160, CS = 23, HC = 30) and the validation group (n = 138, HS = 93, CS = 20, HC = 25). The orthogonal partial least-squares discriminant analysis, the value of fold change, and Kruskal-Wallis test with false discovery rate correction (q-value <0.05) were applied to identify differential plasma metabolites. The area under the ROC curve (AUC) was used to evaluate the diagnostic performance of the screened metabolites. The results showed that the plasma levels of aspartic acid, phenylalanine, arginine, lysoPC20:1, lysoPE16:0, lysoPE18:0, and PE (16:0_22:6) were increased in CS compared with HC. The plasma levels of PC (18:1_18:1), PC (20:4_20:4), PE (16:0_18:2), lysoPE20:4, lysoPE18:2, and lysoPE22:6 were decreased, whereas, the plasma level of ceramide (d18:1_24:1) was increased in HS compared with HC. There were 13 differential metabolites in CS (AUC = 0.995) and 15 differential metabolites in HS (AUC = 0.954), compared with HC. A panel of seven biomarkers, including LysoPC20:1, lysoPE16:0, lysoPE18:2, lysoPE20:4, lysoPE22:6, PC (18:1_18:1), and PC (20:4_20:4) showed good discrimination between HS and CS with an AUC of 0.982. Altered plasma amino acids and lipids may provide an objective basis for TCM syndrome differentiation in pediatric CAP.

Effect of You-Gui-Wan on House Dust Mite-Induced Mouse Allergic Asthma via Regulating Amino Acid Metabolic Disorder and Gut Dysbiosis

Chinese herbal remedies have long been used for enhancing immunity and treating asthma. However, the evidence-based efficacy remains to be supported. This study aimed to explore the potential bio-signatures in allergic asthma and the effect of You-Gui-Wan (YGW), a traditional Chinese herbal prescription, on dust mite-induced mouse allergic asthma. Extract of Dermatophagoides pteronyssinus (Der p), a dust mite, was intratracheally administered to induce allergic asthma in mice. Serum metabolomic and 16S rRNA-based microbiome profiling were used to analyze untargeted metabolites with levels significantly changed and gut microbiota composition, respectively. Results indicated that 10 metabolites (acetylcarnitine, carnitine, hypoxanthine, tryptophan, phenylalanine, norleucine, isoleucine, betaine, methionine, and valine), mainly associated with branched-chain amino acid (BCAA) metabolism, aromatic amino acid (AAA) biosynthesis, and phenylalanine metabolism were markedly elevated after Der p treatment. YGW administration reversed the levels for 7 of the 10 identified metabolites, chiefly affecting BCAA metabolism. On 16S DNA sequencing, disordered Der p-induced gut microbiota was significantly alleviated by YGW. Multiple correlation analysis showed a good correlation between gut microbiota composition and levels of selected metabolites. Our study showed YGW administration effectively alleviated BCAA metabolic disorder and improved gut dysbiosis. This study provides support for YGW administration with benefits for allergic asthma.

Emerging Role of Phospholipase-Derived Cleavage Products in Regulating Eosinophil Activity: Focus on Lysophospholipids, Polyunsaturated Fatty Acids and Eicosanoids

Eosinophils are important effector cells involved in allergic inflammation. When stimulated, eosinophils release a variety of mediators initiating, propagating, and maintaining local inflammation. Both, the activity and concentration of secreted and cytosolic phospholipases (PLAs) are increased in allergic inflammation, promoting the cleavage of phospholipids and thus the production of reactive lipid mediators. Eosinophils express high levels of secreted phospholipase A2 compared to other leukocytes, indicating their direct involvement in the production of lipid mediators during allergic inflammation. On the other side, eosinophils have also been recognized as crucial mediators with regulatory and homeostatic roles in local immunity and repair. Thus, targeting the complex network of lipid mediators offer a unique opportunity to target the over-activation and 'pro-inflammatory' phenotype of eosinophils without compromising the survival and functions of tissue-resident and homeostatic eosinophils. Here we provide a comprehensive overview of the critical role of phospholipase-derived lipid mediators in modulating eosinophil activity in health and disease. We focus on lysophospholipids, polyunsaturated fatty acids, and eicosanoids with exciting new perspectives for future drug development.