Adaptive sampling physics-informed neural network method for high-order rogue waves and parameters discovery of the (2 + 1)-dimensional CHKP equation.

Rogue waves are important physical phenomena, which have wide applications in nonlinear optics, hydrodynamics, Bose-Einstein condensates, and oceanic and atmospheric dynamics. We find that when using the original PINNs to study rogue waves of high dimensional PDEs, the prediction performance will become very poor, especially for high-order rogue waves due to that the randomness of selection of sample points makes insufficient use of the physical information describing the local sharp regions of rogue waves. In this paper, we propose an adaptive sampling physics-informed neural network method (ASPINN), which renders the points in local sharp regions to be selected sufficiently by a new adaptive search algorithm to lead to a prefect prediction performance. To valid the performance of our method, the (2+1)-dimensional CHKP equation is taken as an illustrative example. Experimental results reveal that the original PINNs can hardly be able to predict dynamical behaviors of the high-order rogue waves for the CHKP equation, but the ASPINN method can not only predict dynamical behaviors of these high-order rogue waves, but also greatly improve the prediction efficiency and accuracy to four orders of magnitude. Then, the data-driven inverse problem for the CHKP equation with different levels of corrupted noise is studied to show that the ASPINN method has good robustness. Moreover, some main factors affecting the neural network performance are discussed in detail, including the size of training data, the number of layers of the neural network, and the number of neurons per layer.

Myricetin alleviated immunologic contact urticaria and mast cell degranulation via the PI3K/Akt/NF-κB pathway.

Immunologic contact urticaria (ICU) is characterized by the wheal and flare reaction from direct contact with a chemical or protein agent, which involves a type I hypersensitivity mediated by allergen-specific immunoglobulin E (sIgE). Myricetin (Myr), a bioactive flavonoid, exhibits antiinflammatory activities. Our results showed that treatment with Myr could alleviate ICU symptoms, including a decrease in the number of wheals and scratching, and inhibit ear swelling in the IgE/DNFB-induced mice. The serum level of IgE, histamine, interleukin (IL)-4, TNF-α, and MCP-1 were reduced in Myr-treated mice. Myr also attenuated mast cells (MCs) degranulation and H-PGDS, TSLP, IL-33, PI3K, Akt, and NF-κB mRNA levels in ICU model. The IgE-mediated anaphylaxis mouse models demonstrated anti-allergic effects of Myr. In vitro analysis showed that Myr reduced IgE-induced calcium (Ca2+ ) influx, suppressed degranulation, and chemokine release in LAD2 cells (human primary mast cells). Myr can significantly inhibited PLCγ1, Akt, NF-κB, and p38 phosphorylation. In conclusion, the study demonstrated that Myr alleviate ICU symptoms and inhibit mast cell activation via PI3K/Akt/NF-κB signal pathway.

Protein kinase C mediates juvenile hormone-dependent phosphorylation of Na+/K+-ATPase to induce ovarian follicular patency for yolk protein uptake.

In oviparous animals, vitellogenesis is prerequisite to egg production and embryonic growth after oviposition. For successful insect vitellogenesis and oogenesis, vitellogenin (Vg) synthesized in the fat body (homologue to vertebrate liver and adipose tissue) must pass through the intercellular channels, a condition known as patency in the follicular epithelium, to reach the surface of oocytes. This process is controlled by juvenile hormone (JH) in many insect species, but the underlying mechanisms remain elusive. Previous work has suggested the possible involvement of Na+/K+-ATPase in patency initiation, but again, the regulatory cascade of Na+/K+-ATPase for patency initiation has been lacking. Using the migratory locust Locusta migratoria as a model system, we report here that RNAi-mediated knockdown of gene coding for Na+/K+-ATPase, inhibition of its phosphorylation, or suppression of its activity causes loss of patency, resulting in blocked Vg uptake, arrested oocyte maturation, and impaired ovarian growth. JH triggers G protein-coupled receptor (GPCR), receptor tyrosine kinase (RTK), phospholipase C (PLC), inositol trisphosphate receptor (IP3R), and protein kinase C (PKC) to phosphorylate Na+/K+-ATPase α-subunit at amino acid residue Ser8, consequently activating Na+/K+-ATPase for the induction of patency in vitellogenic follicular epithelium. Our results thus point to a previously unidentified mechanism by which JH induces the phosphorylation and activation of Na+/K+-ATPase via a signaling cascade of GPCR, RTK, PLC, IP3R, and PKC. The findings advance our understanding of JH regulation in insect vitellogenesis and oogenesis.

Dehydroandrographolide inhibits IgE-mediated anaphylactic reactions via calcium signaling pathway.

The classical mast cells degranulation pathway is mediated by FcεRI aggregation and varies in strength among subjects. Dehydroandrographolide (DA) is one of principal components of Andrographis paniculata (Burm.f.) Nees (family: Acanthaceae) and considered the main contributors of its therapeutic properties, such as anti-tumor. In this study, inhibition of IgE-mediated anaphylactic reactions and anti-inflammatory potential of DA were investigated. The anti-anaphylactic activity of DA was investigated using skin swelling and extravasation assays in vivo and mast cell degranulation assay in vitro. The release of cytokines was measured using ELISA kits. Human Phospho-Kinase Array kit and western blotting were used to explore the related molecular signaling pathways. DA inhibited IgE-mediated mast cell activation, including degranulation and release of cytokines in vitro. Moreover, DA reduced the degree of swelling and Evans blue exudation of mice paw in a dose-dependent manner by inhibiting mast cell degranulation. DA obviously reduced the concentrations of histamine, TNF-α, MCP-1, IL-8, IL-13, and IL-4 in mice serum and inhibited IgE-mediated anaphylactic reactions as a potential P-PLCγ inhibitor. Our study reveals that DA can inhibit allergic responses in vivo and in vitro, and it may be regarded as a novel P-PLCγ inhibitor for preventing mast cell-immediate and delayed allergic diseases.

Neohesperidin suppresses IgE-mediated anaphylactic reactions and mast cell activation via Lyn-PLC-Ca2+ pathway.

Mast cells play an essential role in IgE-FcεR1-mediated allergic diseases. Citrus aurantium is a prolific source of flavonoids with various biological activities, including anti-inflammatory, antioxidant, and anti-tumor efficacies. Neohesperidin is a novel flavonoid isolated from the leaves of C. aurantium. In this study, the anti-allergic and anti-inflammatory potentials of neohesperidin were investigated along with its molecular mechanism. The anti-anaphylactic activity of neohesperidin was evaluated through hind paw extravasation study in mice. Calcium imaging was used to assess intracellular Ca2+ mobilization. The levels of cytokines and chemokines were measured using enzyme immunoassay kits. Western blotting was used to explore the related molecular signaling pathways. Neohesperidin suppressed IgE-induced mast cell activations, including degranulation and secretion of cytokines and eicosanoids through inhibiting phosphorylation of Lyn kinase. Neohesperidin inhibited the release of histamine and other proinflammatory cytokines through a mast cell-dependent passive cutaneous anaphylaxis animal model. Histological studies demonstrated that neohesperidin substantially inhibited IgE-induced cellular infiltration and attenuated mast cell activation in skin tissue. In conclusion, our study revealed that neohesperidin could inhibit allergic responses in vivo and in vitro, and the molecule may be regarded as a novel agent for preventing mast cell-immediate and delayed allergic diseases.

Mivacurium induce mast cell activation and pseudo-allergic reactions via MAS-related G protein coupled receptor-X2.

BACKGROUND: Mivacurium is a non-depolarizing muscle relaxant and widely used as a short-acting anesthetic. Pseudo-allergic reactions to mivacurium occur when it is administered during perioperative anesthesia. These reactions may present a serious threat to the patient's life, particularly in children. METHODS: MAS-related G protein coupled receptor-related pseudo-allergic reactions that were induced by mivacurium were investigated using skin swelling and extravasation assays in vivo and mast cell degranulation assay in vitro. RESULTS: Mivacurium caused pseudo-allergic reactions in wild-type mice by inducing mast cells to release histamine. However, it did not induce a similar phenomenon in KitW-sh/W-sh mice. Furthermore, MrgprB2-knockout mice displayed no inflammatory response to mivacurium. Mivacurium induced LAD2 cell degranulation in a dose-dependent manner. Mivacurium stimulated intracellular calcium ion (Ca2+) influx in MRGPRX2-HEK293 cells but not in NC-HEK293 cells. However, mivacurium induced the release of only low levels of mediators in LAD2 cells transfected with MRGPRX2-targeted small interfering (si)RNA. Notably, cytokine release was not observed in LAD2 cells even when stimulated with high concentrations of mivacurium. CONCLUSION: Mivacurium activated MRGPRX2 and triggered mast cell degranulation, leading to anaphylactoid reactions. However, mivacurium did not induce the release of other cytokines. Therefore, the targeting of MRGPRX2 can potentially block mivacurium-induced adverse drug effects, particularly pseudo-allergic reactions.

Hypoxic exosomes facilitate bladder tumor growth and development through transferring long non-coding RNA-UCA1.

BACKGROUND: To overcome the hostile hypoxic microenvironment of solid tumors, tumor cells secrete a large number of non-coding RNA-containing exosomes that facilitate tumor development and metastasis. However, the precise mechanisms of tumor cell-derived exosomes during hypoxia are unknown. Here, we aim to clarify whether hypoxia affects tumor growth and progression by transferring long non-coding RNA-urothelial cancer-associated 1 (lncRNA-UCA1) enriched exosomes secreted from bladder cancer cells. METHODS: We used bladder cancer 5637 cells with high expression of lncRNA-UCA1 as exosome-generating cells and bladder cancer UMUC2 cells with low expression of lncRNA-UCA1 as recipient cells. Exosomes derived from 5637 cells cultured under normoxic or hypoxic conditions were isolated and identified by transmission electron microscopy, nanoparticle tracking analysis and western blotting analysis. These exosomes were co-cultured with UMUC2 cells to evaluate cell proliferation, migration and invasion. We further investigated the roles of exosomal lncRNA-UCA1 derived from hypoxic 5637 cells by xenograft models. The availability of lncRNA-UCA1 in serum-derived exosomes as a biomarker for bladder cancer was also assessed. RESULTS: We found that hypoxic exosomes derived from 5637 cells promoted cell proliferation, migration and invasion, and hypoxic exosomal RNAs could be internalized by three bladder cancer cell lines. Importantly, lncRNA-UCA1 was secreted in hypoxic 5637 cell-derived exosomes. Compared with normoxic exosomes, hypoxic exosomes derived from 5637 cells showed the higher expression levels of lncRNA-UCA1. Moreover, Hypoxic exosomal lncRNA-UCA1 could promote tumor growth and progression though epithelial-mesenchymal transition, in vitro and in vivo. In addition, the expression levels of lncRNA-UCA1 in the human serum-derived exosomes of bladder cancer patients were higher than that in the healthy controls. CONCLUSION: Together, our results demonstrate that hypoxic bladder cancer cells remodel tumor microenvironment to facilitate tumor growth and development though secreting the oncogenic lncRNA-UCA1-enriched exosomes and exosomal lncRNA-UCA1 in human serum has the possibility as a diagnostic biomarker for bladder cancer.

Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as the cell membrane stationary phase. The specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients that specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4.

Integrated OMICs approach reveals energy metabolism pathway is vital for Salmonella Pullorum survival within the egg white.

Eggs, an important part of a healthy daily diet, can protect chicken embryo development due to the shell barrier and various antibacterial components within the egg white. Our previous study demonstrated that Salmonella Pullorum, highly adapted to chickens, can survive in the egg white and, therefore, be passed to newly hatched chicks. However, the survival strategy of Salmonella Pullorum in antibacterial conditions remains unknown. The overall transcripts in the egg white showed a large-scale shift compared to LB broth. The expression of common response genes and pathways, such as those involved in iron uptake, biotin biosynthesis, and virulence, was significantly changed, consistent with the other transovarial transmission serovar Enteritidis. Notably, membrane stress response, amino acid metabolism, and carbohydrate metabolism were specifically affected. Additional upregulated functionally relevant genes (JI728_13095, JI728_13100, JI728_17960, JI728_10085, JI728_15605, and nhaA) as mutants confirmed the susceptible phenotype. Furthermore, fim deletion resulted in an increased survival capacity in the egg white, consistent with the downregulated expression. The second-round RNA-Seq analysis of the Δfim mutant in the egg white revealed significantly upregulated genes compared with the wild type in the egg white responsible for energy metabolism located on the hyc and hyp operons regulated by FhlA, indicating the Δfim mutant cannot receive enough oxygen and switched to fermentative growth due to its inability to attach to the albumen surface. Together, this study provides a first estimate of the global transcriptional response of Salmonella Pullorum under antibacterial egg white and highlights the new potential role of fim deletion in optimizing energy metabolism pathways that may assist vertical transmission. IMPORTANCE: Pullorum disease, causing serious embryo death and chick mortality, results in substantial economic losses worldwide due to transovarial transmission. Egg-borne outbreaks are frequently reported in many countries. The present study has filled the knowledge gap regarding how the specific chicken-adapted pathogen Salmonella Pullorum behaves within the challenging environment of egg white. The deletion of the fim fimbrial system can increase survival in the albumen, possibly by reprogramming metabolism-related gene products, which reveals a new adaptive strategy of pathogens. Moreover, the comparison, including previous research on Salmonella Enteritidis, capable of vertical transmission, aims to provide diversified data sets in the field and further help to implement reasonable and effective measures to improve both food safety and animal health.

Myricetin served as antagonist for negatively regulate MRGPRX2 mediated pseudo-allergic reactions through CD300f/SHP1/SHP2 phosphorylation.

BACKGROUND: Mas-related G protein-coupled receptor X2 (MRGPRX2) plays a vital role in mast cells (MCs) degranulation and pseudo-allergic reactions. Leukocyte mono-immunoglobulin-like receptor 3 (CD300f) can negatively regulate MCs degranulation. Identification of drug candidates which target CD300f represents a promising prospect in drug development. Myricetin is widely distributed in plants and has been reported to inhibit allergic reactions in OVA-induced murine models. OBJECTIVE: This study aims to determine whether myricetin can activate CD300f to arrest MCs degranulation mediated by MRGPRX2. RESULTS: Myricetin inhibited the allergic mediator and cytokine release triggered by MRGPRX2 in vivo and in vitro. Under C48/80 stimulation, the release of ß-hexosaminidase, TNF-α, IL-8 and MCP-1 in CD300f knockdown in LAD2 cells was significantly increased compared with NC-LAD2 cells. Myricetin displayed good structural affinity (KD = 7.21 × 10-5) with CD300f by SPR. Molecular docking results showed that hydrogen bonds were formed between myricetin and CD300f, indicating high binding ability (5.6653). Myricetin can upregulate the phosphorylation of SHP-1 and SHP-2 and dephosphorylation in the MRGPRX2 signaling pathway, involving PLCγ1, AKT, P38, and ERK1/2. CONCLUSION: In the present study, myricetin is identified as an exogenous ligand for CD300f, which negatively regulates MRGPRX2-mediated MCs activation via CD300f to inhibit MCs degranulation and pseudo-allergic reactions.

Mobilome-driven partitions of the resistome in Salmonella.

IMPORTANCE: Antimicrobial resistance (AMR) has become a significant global challenge, with an estimated 10 million deaths annually by 2050. The emergence of AMR is mainly attributed to mobile genetic elements (MGEs or mobilomes), which accelerate wide dissemination among pathogens. The interaction between mobilomes and AMR genes (or resistomes) in Salmonella, a primary cause of diarrheal diseases that results in over 90 million cases annually, remains poorly understood. The available fragmented or incomplete genomes remain a significant limitation in investigating the relationship between AMR and MGEs. Here, we collected the most extensive closed Salmonella genomes (n = 1,817) from various sources across 58 countries. Notably, our results demonstrate that resistome transmission between Salmonella lineages follows a specific pattern of MGEs and is influenced by external drivers, including certain socioeconomic factors. Therefore, targeted interventions are urgently needed to mitigate the catastrophic consequences of Salmonella AMR.

Artemisinic acid attenuated symptoms of substance P-induced chronic urticaria in a mice model and mast cell degranulation via Lyn/PLC-p38 signal pathway.

BACKGROUND: Chronic urticaria (CU) is a common skin disease that affects about 1% of the world's population of all ages and seriously affects patients' quality of life. Therefore, further safe and effective treatments are urgently needed. Therefore, artemisinic acid was investigated in the present study due to its pharmacologic effect on inhibiting mast cell degranulation and chronic urticaria in a mouse model. RESULTS: 4Artemisinic acid decreased the symptoms of substance P-induced chronic urticaria in the mouse model and alleviated secretagogue-induced local cutaneous and systemic anaphylaxis through the Lyn-PLC-p38-NF-κB signaling pathway. Artemisinic acid inhibited mast cell degranulation and pro-inflammatory cytokine production in vitro. Mechanism analysis demonstrated that it could arrest mast cell activation through the Lyn-PLC-p38/ERK1/2/AKT-NF-κB signaling pathway. Based on the results of in vitro kinase assay of Lyn and PLC, artemisinic acid was a potential small molecule inhibitor of Lyn. Artemisinic acid displayed good structural affinity (KD = 2.64 × 10-6) with Lyn SPR results. CONCLUSION: Artemisinic acid can attenuate substance P/MRGPRX2-mediated chronic urticaria and mast cell activation. Artemisinic acid is an antagonist of Lyn kinase and can be developed as a drug candidate to treat allergic diseases.

Surface-Modified Approach to Fabricate Nafion Membranes Covalently Bonded with Polyhedral Oligosilsesquioxane for Vanadium Redox Flow Batteries.

An aminopropyl isobutyl polyhedral oligosilsesquioxane (NH2-POSS) surface-modified Nafion membrane has been designed by chemical grafting for vanadium redox flow batteries (VRFBs). NH2-POSS is a cage-like macromer consisting of an inorganic Si8O12 core surrounded by seven inert isobutyl groups and one active aminopropyl group. The sulfonic acid groups on the surface of Nafion can be activated by 1,1-carbonyldiimidazole for further modification with NH2-POSS. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) prove that NH2-POSS has been successfully grafted on the surface of a Nafion 115 membrane. Although the proton conductivity decreases slightly, the organic-inorganic hybrid membranes display enhanced ion selectivity and excellent dimensional stability with lower water uptake and swelling ratio than Nafion 115. Moreover, two-dimensional-grazing incidence X-ray diffraction (2D-GIXRD) reveals that the introduction of NH2-POSS forms a POSS layer on the surface of the membrane and narrows the space of Nafion clusters, which helps to block VO2+ permeation. A VRFB with the surface-modified Nafion membrane displays an outstanding performance with an average Coulombic efficiency (CE) of 98.7% and energy efficiency (EE) of 84.5% at a current density of 80 mA cm-2, superior to those of the Nafion 115 membrane (CE = 95.7%, EE = 81.7%). Furthermore, the cell holds a high capacity retention of 49.2% after 1000 charge-discharge cycles, in contrast to that of 41.9% for the cell with Nafion 115 after only 200 cycles. The results suggest that the surface-modified hybrid membrane is a promising strategy to overcome the vanadium ion crossover in VRFBs.

Alpha-linolenic acid inhibits IgE-mediated anaphylaxis by inhibiting Lyn kinase and suppressing mast cell activation.

Excessive reactions to allergens can induce systemic, life-threatening physiological dysfunction (anaphylaxis) in humans. The surface of mast cells expresses high-affinity IgE receptors that play a vital role during anaphylaxis. Alpha-linolenic acid (ALA) is an essential non-toxic fatty acid in humans. Since it has been reported having potential to regulate pro-inflammatory reactions, we postulated that ALA could inhibit anaphylaxis by down-regulating Lyn kinase phosphorylation. We found that local and systematic inflammation induced by albumin from chicken egg white (OVA) were attenuated by ALA in vivo. Furthermore, ALA inhibited IgE-mediated Ca2+ mobilization, degranulation, and cytokine release in Laboratory of Allergic Disease 2 (LAD2) cells. The western blot results showed that ALA down-regulate the FcεRI/Lyn/Syk signaling pathway by suppressing Lyn kinase activity. Therefore, ALA could serve as a therapeutic drug candidate for preventing IgE-mediated anaphylaxis.

Sphingomonas xinjiangensis sp. nov., isolated from desert sand.

A Gram-negative, aerobic, motile, Sphingomonas-like rod, strain 10-1-84(T), was isolated from a sand sample collected from the desert of Xinjiang, China. The isolate contained Q-10 as the predominant ubiquinone and C(18 : 1)ω7c, C(16 : 0), C(16 : 1)ω7c and C(14 : 0) 2-OH as the major fatty acids. The polyamine pattern contained predominantly sym-homospermidine. The main polar lipids were sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine and an unknown polar lipid. The DNA G+C content was 63.3 mol%. 16S rRNA gene sequence similarity between strain 10-1-84(T) and the type strains of species of the genus Sphingomonas ranged from 91.11 to 96.54 %. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain 10-1-84(T) belonged to the genus Sphingomonas. On the basis of phylogenetic analysis and physiological and biochemical characterization, strain 10-1-84(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas xinjiangensis sp. nov. is proposed. The type strain is 10-1-84(T) ( = CCTCC AB 208035(T)  = NRRL B-51332(T)).

α-Linolenic acid attenuates pseudo-allergic reactions by inhibiting Lyn kinase activity.

BACKGROUND: Pseudo-allergic reactions are potentially fatal hypersensitivity responses caused by mast cell activation. α-linolenic acid (ALA) is known for its anti-allergic properties. However, its potential anti-pseudo-allergic effects were not much investigated. PURPOSE: To investigate the inhibitory effects of ALA on IgE-independent allergy in vitro, and in vivo, as well as the mechanism underlying its effects. METHODS/STUDY DESIGNS: The anti-anaphylactoid activity of ALA was evaluated in passive cutaneous anaphylaxis reaction (PCA) and systemic anaphylaxis models. Calcium imaging was used to assess intracellular Ca2+ mobilization. The release of cytokines and chemokines was measured using enzyme immunoassay kits. Western blot analysis was conducted to investigate the molecules of Lyn-PLCγ-IP3R-Ca2+ and Lyn-p38/NF-κB signaling pathway. RESULTS: ALA (0, 1.0, 2.0, and 4.0 mg/kg) dose-dependently reduced serum histamine, chemokine release, vasodilation, eosinophil infiltration, and the percentage of degranulated mast cells in C57BL/6 mice. In addition, ALA (0, 50, 100, and 200 µM) reduced Compound 48/80 (C48/80) (30 µg/ml)-or Substance P (SP) (4 µg/ml)-induced calcium influx, mast cell degranulation and cytokines and chemokine release in Laboratory of Allergic Disease 2 (LAD2) cells via Lyn-PLCγ-IP3R-Ca2+ and Lyn-p38/NF-κB signaling pathway. Moreover, ALA (0, 50, 100, and 200 µM) inhibited C48/80 (30 µg/ml)- and SP (4 µg/ml)-induced calcium influx in Mas-related G-protein coupled receptor member X2 (MrgX2)-HEK293 cells and in vitro kinase assays confirmed that ALA inhibited the activity of Lyn kinase. In response to 200 µM of ALA, the activity of Lyn kinase by (7.296 ± 0.03751) × 10-5 units/µl and decreased compared with C48/80 (30 µg/ml) by (8.572 ± 0.1365) ×10-5 units/µl. CONCLUSION: Our results demonstrate that ALA might be a potential Lyn kinase inhibitor, which could be used to treat pseudo-allergic reaction-related diseases such as urticaria.

Roles of Endogenous Melatonin in Resistance to Botrytis cinerea Infection in an Arabidopsis Model.

Melatonin is an important bioactive molecule in plants. Two synthetases, N-acetylserotonin methyltransferase (ASMT) and serotonin N-acetyltransferase (SNAT) are involved in the final two steps of melatonin synthesis. Melatonin participates in responses to a variety of biotic and abiotic stresses in plants, but few studies have addressed the roles of endogenous melatonin in pathogen resistance. We investigated the role of endogenous melatonin in resistance to Botrytis cinerea infection in an Arabidopsis thaliana model system. Plant lines that overexpressed ASMT or SNAT through genetic manipulation showed upregulated expression of resistance genes PR1 and PR5, transcription factor gene WRKY33, and jasmonic acid (JA) defense pathway marker gene PDF1.2, and downregulated transcription factor gene MYC2 in JA signaling pathway. Higher melatonin content also enhanced the activity of antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD), increased JA content, reduced plant disease symptoms, and reduced lesion size in leaves. These findings indicate that endogenous melatonin enhances plant resistance to B. cinerea infection. In contrast, ASMT and SNAT gene silencing lines showed opposite results and were more susceptible to B. cinerea. Thus, it can be demonstrated that melatonin functions as an effective regulator of plant stress resistance at the genetic level. A schematic model is presented for its role in resistance to B. cinerea infection. Our findings also helped to elucidate the associated signal transduction pathways and interactions between melatonin and other plant hormones.

Kaempferol ameliorates secretagogue-induced pseudo-allergic reactions via inhibiting intracellular calcium fluctuation.

OBJECTIVES: To investigate the inhibitory effects of Kaempferol, a natural flavonol active compound, on pseudo-allergic reactions (in vivo and in vitro), particularly on the mechanism underlying its effect in human mast cells. METHODS: Compound 48/80 (C48/80)-induced immunoglobulin E (IgE)-independent passive cutaneous anaphylaxis (PCA) model and systemic anaphylaxis were applied to investigate the anti-allergic activity of Kaempferol. The degranulation assay, calcium imaging and the secretion of cytokines and chemokines were used to evaluate the inhibitory effect on mast cell activation. Western blot analysis was performed to investigate intracellular calcium fluctuation-related signalling pathways. KEY FINDINGS: Kaempferol dose-dependently attenuated C48/80-induced mice hind paw swelling, dye extravasation and skin mast cell degranulation, and rehabilitated the hypothermia, as well as reduced the serum concentrations of histamine, tryptase, tumour necrosis factor-alpha (TNF-α), interleukin-8 (IL-8) and monocyte chemo-attractant protein-1 (MCP-1). Furthermore, Kaempferol suppressed C48/80-triggered human MC degranulation and calcium fluctuations by inhibiting phospholipase Cγ (PLCγ) phosphorylation and subsequent cytokines synthesis pathways. CONCLUSIONS: The inhibition of the process of PLCγ phosphorylation to Ca2+ mobilization represents a major strategy in Kaempferol-suppressed pseudo-allergic reactions. Thus, Kaempferol could be considered as a therapeutic drug candidate for non-IgE-mediated allergic reactions or inflammations.

Inhibitory function of Shikonin on MRGPRX2-mediated pseudo-allergic reactions induced by the secretagogue.

BACKGROUND: Mast cells (MCs) are crucial effectors in allergic disorders by secreting inflammatory mediators. The Mas-related G-protein-coupled receptor X2 (Mrgprx2) was shown to have a key role in IgE-independent allergic reactions. Therefore, potential drug candidates that directly target Mrgprx2 could be used to treat pseudo-allergic diseases. Shikonin, an active ingredient derived from Lithospermum erythrorhizon Sieb. et Zucc has been used for its anti-inflammatory properties since ancient China. PURPOSE: To investigate the inhibitory effects of Shikonin on IgE-independent allergy both in vitro and in vivo, as well as the mechanism underlying its effects. METHODS/STUDY DESIGNS: The anti-anaphylactoid activity of Shikonin was evaluated in PCA and systemic anaphylaxis models, Calcium imaging was used to assess intracellular Ca2+ mobilization. The release of cytokines and chemokines was measured using enzyme immunoassay kits. Western blot analysis was conducted to investigate the molecules of PLCγ-PKC-IP3 signaling pathway. The analytical method of surface plasmon resonance was employed to study the interaction between Shikonin and potential target protein Mrgprx2. RESULTS: Shikonin can suppress compound 48/80 (C48/80)-induced PCA, active systemic anaphylaxis, and MCs degranulation in mice in a dose-dependent manner. In addition, Shikonin reduced C48/80-induced calcium flux and suppressed LAD2 cell degranulation via PLCγ-PKC-IP3 signaling pathway. Moreover, Shikonin was found to inhibit C48/80-induced Mrgprx2 expression in HEK cells, displaying specific interactions with the Mrgprx2 protein. CONCLUSION: Shikonin could be a potential antagonist of Mrgprx2, thereby inhibiting pseudo-allergic reactions through Ca2+ mobilization.

A mast-cell-specific receptor mediates Iopamidol induced immediate IgE-independent anaphylactoid reactions.

Iopamidol is a radiographic contrast media which caused a very high incidence of anaphylactic reactions. Mast cells are sentinel cells in host defense reactions during immediate hypersensitivity responses and anaphylactic responses. Mas-related G protein-coupled receptor X2 (MRGPRX2) is a kind of mast cell specific receptor, which triggers mast cell degranulation in anaphylactic reactions. Mice MrgprB2 is a homologous gene of MRGPRX2. We sought to better understand the anaphylactic reactions induced by Iopamidol and the mechanisms involving MRGPRX2. The MRGPRX2-related anaphylactic reactions induced by Iopamidol were investigated using the hindpaw swelling and extravasation assay in vivo and a calcium imaging assay was used for mast cell intracellular calcium responses detection and mast cell release of anaphylactic mediators, such as ß-hexosaminidase, histamine and TNF-α, was also detected in vitro. The mast cell deficient KitW-sh/W-sh mice and MrgprB2 knockout mice exhibited a reduced Iopamidol-induced inflammation effect compared with wild type mice. Furthermore, human mast cells that express MRGPRX2 were activated by Iopamidol in a dose-dependent manner, meanwhile MRGPRX2 knockdown mast cells showed reduced intracellular calcium responses and anaphylactic mediators release effect. It could be concluded that Iopamidol-induced anaphylactoid reactions were MRGPRX2 mediated to provoke mast cells Ca2+ mobilization and degranulation.