Encephalitis ; metabolism ; pathology ; Microglia ; metabolism ; pathology ; Receptors, Leukotriene ; metabolism ; physiology

OBJECTIVETo investigate whether cysteinyl leukotriene receptor 1 (CysLT₁ receptor) is involved in rotenone-induced injury of PC12 cells.

METHODSAfter 24 h treatment with rotenone or with rotenone and the CysLT₁ receptor antagonist montelukast, PC12 cell viability was determined by the colorimetric MTT reduction assay. After PC12 cells were treated with various concentrations of rotenone for 24 h or with 3 μmol/L rotenone for various durations, the expression of CysLT(1) receptor was determined by Western blotting, and its intracellular distribution was detected by immunocytochemistry.

RESULTSRotenone (0.3-30 μmol/L) induced PC12 cell injury; this injury was significantly attenuated by montelukast at 1 and 5 μmol/L.The expression of CysLT(1) receptor increased after rotenone treatment at 1-10 μmol/L, or at 3 μmol/L for 3 and 24 h. Rotenone caused concentration-and time-dependent translocation of CysLT₁ receptor from the nucleus to the cytosol.

CONCLUSIONCysteinyl leukotriene receptor 1 is involved in rotenone-induced injury of PC12 cells.

Animals ; PC12 Cells ; Rats ; Receptors, Leukotriene ; metabolism ; physiology ; Rotenone ; toxicity

OBJECTIVETo establish a method for screening cysteinyl leukotriene receptor 2 (CysLT(2)) antagonists and to preliminarily screen a series of synthetic compounds.

METHODSRat glioma cell line (C6 cells) highly expressing CysLT(2) receptor was used. Intracellular calcium concentration was measured after stimulation with the agonist LTD(4),which was used to screen compounds with antagonist activity for CysLT(2) receptor. Bay u9773, a CysLT1/CysLT(2) receptor non-selective antagonist, and AP-100984, a CysLT(2) receptor antagonist, were used as control.

RESULTPT-PCR showed a higher expression of CysLT(2) receptor in C6 cells. LTD(4) at 1 mumol/L significantly increased intracellular calcium in C6 cells; the maximal effect was about 37.5% of ATP, a positive stimulus.LTD(4)-induced increase of intracellular calcium was blocked by CysLT(2) receptor antagonists, but not by CysLT(1) receptor antagonists. Among the synthetic compounds, D(XW-)1,2,13,23,29 and 30 inhibited LTD(4)-induced increase of intracellular calcium.

CONCLUSIONLTD(4)-induced change in intracellular calcium in C6 cells can be used as a screening method for CysLT(2) receptor antagonists. The compounds, D(XW-)1,2,13,23,29 and 30, possess antagonist activity for CysLT(2) receptor.

Animals ; Brain Neoplasms ; pathology ; Cell Line, Tumor ; Drug Evaluation, Preclinical ; methods ; Glioma ; pathology ; Leukotriene Antagonists ; isolation & purification ; Leukotriene D4 ; metabolism ; pharmacology ; Rats ; Receptors, Leukotriene ; chemistry

Based on the findings recently reported, cysteinyl leukotriene receptors, both CysLT (1) and CysLT(2) receptors, are involved in the ischemic and traumatic brain injury in vivo. CysLT(1)receptor regulates the increased permeability of blood-brain barrier and the related vasogenic brain edema, astrocyte proliferation, and inflammatory responses after brain ischemia; while CysLT(2)receptor regulates AQP4 expression and the related cytotoxic brain edema, and astrocyte injury. A new subtype of CysLT receptor, GPR17, is also involved in brain ischemic injury. The roles of CysLT receptors in brain injury or neuroprotection from the injury should be further understood. This understanding is necessary to accelerate the screening and development of the new drugs for the prevention and treatment of brain injury with the receptors as therapeutic targets.
Aquaporin 4 ; metabolism ; Brain Injuries ; metabolism ; Brain Ischemia ; metabolism ; Humans ; Receptors, G-Protein-Coupled ; metabolism ; Receptors, Leukotriene ; metabolism

OBJECTIVE: To explore the expression patterns, prognostic implications, and biological role of leukotriene B4 receptor (LTB4R) in patients with acute myeloid leukemia (AML). METHODS: We collected the data of mRNA expression levels and clinical information of patients with AML from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database for mRNA expression analyses, survival analyses, Cox regression analyses and correlation analyses using R studio to assess the expression patterns and prognostic value of LTB4R. The correlation of LTB4R expression levels with clinical characteristics of the patients were analyzed using UALCAN. The co-expressed genes LTB4R were screened from Linkedomics and subjected to functional enrichment analysis. A protein-protein interaction network was constructed using STRING. GSEA analyses of the differentially expressed genes (DEGs) were performed based on datasets from TCGA-LAML stratified by LTB4R expression level. We also collected peripheral blood mononuclear cells (PBMCs) from AML patients and healthy donors for examination of the mRNA expression levels of LTB4R and immune checkpoint genes using qRT-PCR. We also examined serum LTB4R protein levels in the patients using ELISA. RESULTS: The mRNA expression level of LTB4R was significantly increased in AML patients (4.898±1.220 vs 2.252±0.215, P < 0.001), and an elevated LTB4R expression level was correlated with a poor overall survival (OS) of the patients (P=0.004, HR=1.74). LTB4R was identified as an independent prognostic factor for OS (P=0.019, HR=1.66) and was associated with FAB subtypes, cytogenetic risk, karyotype abnormalities and NPM1 mutations. The co- expressed genes of LTB4R were enriched in the functional pathways closely associated with AML leukemogenesis, including neutrophil inflammation, lymphocyte activation, signal transduction, and metabolism. The DEGs were enriched in differentiation, activation of immune cells, and cytokine signaling. Examination of the clinical serum samples also demonstrated significantly increased expressions of LTB4R mRNA (P=0.044) and protein (P=0.008) in AML patients, and LTB4R mRNA expression was positively correlated with the expression of the immune checkpoint HAVCR2 (r= 0.466, P=0.040). CONCLUSION LTB4R can serve as a novel biomarker and independent prognostic indicator of AML and its expression patterns provide insights into the crosstalk of leukemogenesis signaling pathways involving tumor immunity and metabolism.
Humans ; Leukemia, Myeloid, Acute/metabolism* ; Leukocytes, Mononuclear/metabolism* ; Prognosis ; RNA, Messenger/metabolism* ; Receptors, Leukotriene B4/genetics*

OBJECTIVETo determine whether cysteinyl leukotriene receptor agonist LTD(4) and cysteinyl leukotriene receptor 1 (CysLT(1)) antagonist pranlukast affect the differentiation of human neuroblastoma SK-N-SH cells.

METHODSSK-N-SH cell morphological changes induced by LTD(4), pranlukast and LTD(4) + pranlukast were observed with retinoid acid (RA) as the positive control. The expressions of CysLT(1) and CysLT(2) receptors were detected by immunoblotting analysis, and the expression of microtubule-associated protein-2 (MAP-2), a neuron marker, was detected by fluorescent immunostaining.

RESULTThe immunoblotting results showed that SK-N-SH cells expressed CysLT(1) receptor moderately, and CysLT(2) receptor highly. The morphological results showed that RA, pranlukast and LTD(4) + pranlukast induced the compaction of the cell bodies and the outgrowth of neurites, while LTD(4) had no significant effect. The immunostaining results showed that MAP-2 was distributed in the cell bodies in control or pranlukast-treated cells; it was distributed in cell bodies and neuritis in RA-treated cells. Pranlukast increased the numbers of MAP-2-positive cells.

CONCLUSIONThe CysLT(1)receptor antagonist pranlukast modulates the differentiation of SK-N-SH cells.

Cell Differentiation ; drug effects ; Cell Line, Tumor ; Chromones ; pharmacology ; Humans ; Immunoblotting ; Immunohistochemistry ; Leukotriene Antagonists ; pharmacology ; Leukotriene D4 ; pharmacology ; Membrane Proteins ; metabolism ; Microtubule-Associated Proteins ; metabolism ; Neuroblastoma ; metabolism ; pathology ; Receptors, Leukotriene ; metabolism

OBJECTIVETo investigate the effects of CysLT receptor agonist leukotriene D4(LTD4) and antagonists on activation of microglia BV2 cells.

METHODSThe expression of CysLT1 and CysLT2 protein was determined by Western blotting and immunostaining in microglia BV2 cells. BV2 cells were pretreated with or without CysLT1 receptor selective antagonist montelukast, CysLT2 receptor selective antagonist HAMI 3379, or CysLT1/CysLT2 receptor dual antagonist BAY u9773 for 30 min, then the cells were treated with LTD4 for 24 h. Cell viability was detected by MTT reduction assay. Phagocytosis and mRNA expression of IL-6 were determined by fluorescent bead tracking and RT-PCR, respectively.

RESULTSIn BV2 cells, LTD4 did not affect proliferation but significantly enhanced phagocytosis and increased IL-6 mRNA expression in a concentration-dependent manner. LTD4 at 100 nmol/L induced a 1.4-fold increase of phagocytic index and a 2-fold up-regulation of IL-6 mRNA expression (P<0.01). HAMI 3379 and BAY u9773 (100 nmol/L) further increased LTD4-induced phagocytosis; BAY u9773 and montelukast decreased LTD4-induced IL-6 mRNA expression, while HAMI 3379 had no effect on that.

CONCLUSIONLTD4 activates BV2 cells in vitro and enhances IL-6 mRNA expression mediated by CysLT1 receptor, LTD4 induces phagocytosis which might be negatively regulated by CysLT2 receptor in BV2 cells.

Acetates ; pharmacology ; Cell Line ; Cell Proliferation ; Cyclohexanecarboxylic Acids ; pharmacology ; Humans ; Interleukin-6 ; metabolism ; Leukotriene Antagonists ; pharmacology ; Leukotriene D4 ; pharmacology ; Microglia ; cytology ; metabolism ; Phagocytosis ; Phthalic Acids ; pharmacology ; Quinolines ; pharmacology ; Receptors, Leukotriene ; metabolism ; SRS-A ; analogs & derivatives ; pharmacology

Animals ; Arachidonate 5-Lipoxygenase ; metabolism ; Brain Diseases ; enzymology ; metabolism ; Disease Models, Animal ; Histamine ; metabolism ; Humans ; Membrane Proteins ; metabolism ; Receptors, Histamine ; metabolism ; Receptors, Leukotriene ; metabolism

OBJECTIVETo determine the effect of cysteinyl receptor agonist leukotriene D(4) (LTD(4)) and its antagonists on rat primary neurons.

METHODSIn the primarily cultured rat cortical neurons, the neuron injury was evaluated by measuring intracellular calcium, 3-(4, 5-dimethylthiazol-2yl)-2, 5-diphenyl tetrazolium bromide (MTT) reduction, and propidium iodide (PI) and Hoechst 33258 staining. The in vitro ischemic injury was induced by oxygen-glucose deprivation (OGD) for 1.5 h and reperfusion for 24 h.

RESULTLTD(4) (0.01-1 micromol/L) did not induce the elevation of intracellular calcium, neuron viability changes and neuron death. OGD-induced injury was not significantly ameliorated by the CysLT(1) receptor antagonists, pranlukast (0.2-10 micromol/L) and montelukast (0.2-10 micromol/L), as well as by the CysLT(1)/CysLT(2) receptor non-selective antagonist, BAY u9773 (0.02-1 micromol/L).

CONCLUSIONNeither agonist nor antagonists of cysteinyl receptors have the effects on the viability and ischemic-like injury in rat primary neurons.

Acetates ; pharmacology ; Animals ; Animals, Newborn ; Calcium ; metabolism ; Cell Hypoxia ; Cell Survival ; drug effects ; Cells, Cultured ; Cerebral Cortex ; cytology ; Chromones ; pharmacology ; Glucose ; pharmacology ; Leukotriene Antagonists ; pharmacology ; Leukotriene D4 ; pharmacology ; Neurons ; cytology ; drug effects ; metabolism ; Quinolines ; pharmacology ; Rats ; Receptors, Leukotriene ; agonists

BACKGROUND AND OBJECTIVES: A recent study has demonstrated a possible involvement of leukotriene C4 synthase (LTC4S) gene polymorphism in ASA-intolerant asthma (AIA) in a Polish population, while no significances were noted in other populations. To investigate the role of genetic polymorphism in AIA development, we screened single nucleotide polymorphisms (SNPs) for the key enzymes involved in arachidonate metabolism, and cysteinyl leukotriene receptor 1 (CYSLTR1) in a larger scale of Korean population with AIA. MATERIALS AND METHODS: 93 AIA and 181 ASA-tolerant asthma (ATA) patients, and 123 normal controls (NC) were enrolled. Single base extension method was applied for genotyping of SNPs in 5-lipoxygenase (ALOX5, -1708G>A, 21C>T, 270G>A, 1728G>A), ALOX5 activating protein (FLAP, 218A>G), cyclooxygenase 2 (COX2, -162C>G, 10T>G, 228G>A), LTC4S (-444A>C), and CYSLTR1 (927T>C). Haplotype analyses for ALOX5 were performed as well. RESULTS: There were no significant differences in allele and genotype frequencies of the SNPs among the three groups (p>0.05). However, the frequency of ALOX5-ht1[G-C-G-A] containing genotype in the AIA group was significantly higher than those of the ATA group (p=0.01, OR =5.0, 95%CI=1.54-17.9) and the normal controls (p=0.03, OR=4.5, 95%CI=1.1-18.4) with a dominant model. CONCLUSION: These results suggest a lack of association between FLAP, COX2, LTC4S, and CYSLTR1 gene polymorphisms, and AIA phenotype in Korean population. However, a possible involvement of ALOX5-ht1[G-C-G-A] in AIA development was suggested.
Alleles ; Arachidonate 5-Lipoxygenase* ; Aspirin ; Asthma* ; Cyclooxygenase 2 ; Genotype ; Haplotypes* ; Humans ; Leukotriene C4 ; Metabolism ; Phenotype ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Receptors, Leukotriene