Role of 15-lipoxygenase/15-hydroxyeicosatetraenoic acid in hypoxic pulmonary arterial hypertension / 生理学报

Pulmonary arterial hypertension (PAH) is a rare disease with a complex aetiology characterized by elevated pulmonary artery resistance, which leads to progressive right ventricular failure and ultimately death. The aberrant metabolism of arachidonic acid in the pulmonary vasculature plays a central role in the pathogenesis of PAH. The levels of 15-lipoxygenase (15-LO) and 15-hydroxyeicosatetraenoic acid (15-HETE) are elevated in the pulmonary arterial endothelial cells (PAECs), pulmonary smooth muscle cells (PASMCs) and fibroblasts of PAH patients. Under hypoxia condition, 15-LO/15-HETE induces pulmonary artery contraction, promotes the proliferation of PAECs and PASMCs, inhibits apoptosis of PASMCs, promotes fibrosis of pulmonary vessels, and then leads to the occurrence of PAH. Here, we review the research progress on the relationship between 15-LO/15-HETE and hypoxic PAH, in order to clarify the significance of 15-LO/15-HETE in hypoxic PAH.

Arachidonic acid Alox15/12-HETE signaling inhibits vascular calcification / 生理学报

This study aims to explore the effects of arachidonic acid lipoxygenase metabolism in vascular calcification. We used 5/6 nephrectomy and high-phosphorus feeding to establish a model of vascular calcification in mice. Six weeks after nephrectomy surgery, vascular calcium content was measured, and Alizarin Red S and Von Kossa staining were applied to detect calcium deposition in aortic arch. Control aortas and calcified aortas were collected for mass spectrometry detection of arachidonic acid metabolites, and active molecules in lipoxygenase pathway were analyzed. Real-time quantitative PCR was used to detect changes in the expression of lipoxygenase in calcified aortas. Lipoxygenase inhibitor was used to clarify the effect of lipoxygenase metabolic pathways on vascular calcification. The results showed that 6 weeks after nephrectomy surgery, the aortic calcium content of the surgery group was significantly higher than that of the sham group (P < 0.05). Alizarin Red S staining and Von Kossa staining showed obvious calcium deposition in aortic arch from surgery group, indicating formation of vascular calcification. Nine arachidonic acid lipoxygenase metabolites were quantitated using liquid chromatography/mass spectrometry (LC-MS) analysis. The content of multiple metabolites (12-HETE, 11-HETE, 15-HETE, etc.) was significantly increased in calcified aortas, and the most abundant and up-regulated metabolite was 12-HETE. Furthermore, we examined the mRNA levels of metabolic enzymes that produce 12-HETE in calcified blood vessels and found the expression of arachidonate lipoxygenase-15 (Alox15) was increased. Blocking Alox15/12-HETE by Alox15 specific inhibitor PD146176 significantly decreased the plasma 12-HETE content, promoted calcium deposition in aortic arch and increased vascular calcium content. These results suggest that the metabolism of arachidonic acid lipoxygenase is activated in calcified aorta, and the Alox15/12-HETE signaling pathway may play a protective role in vascular calcification.

Effect of Alox-15 Polymorphism on GCF Levels of Lipoxin-A4 in Chronic Periodontitis: A Preliminary Study

Lipoxins play an important role in periodontal resolution, hence, investigation of genetic polymorphism of lipoxin gene may provide important information on the role of lipoxins in periodontal disease pathogenesis. The aim of this study was to investigate a polymorphism of C-to-T substitution at position c.-292 in ALOX15 (reticulocyte-type 15 lipoxygenase 1) gene in patients with chronic periodontitis and to associate the polymorphism with gingival crevicular fluid (GCF) lipoxin A4 (LXA4) levels. Forty-five chronic periodontitis and 45 periodontally healthy patients were included in this case-control study. Plaque index, calculus index, sulcus bleeding index, full mouth probing depth (PD) and clinical attachment loss (CAL) were recorded. GCF and blood samples were collected. GCF was analyzed for LXA4 levels by enzyme linked immunosorbant assay. Genotyping of ALOX15 polymorphism was studied using PCR. Mean LXA4 was lower in periodontitis group compared to the periodontally healthy group. There was a negative correlation between CAL and LXA4. The CC genotype was higher in the study group than in the control group. In the study group, mean CAL was significantly lower among individuals with the CT genotype. Mean LXA4 was significantly lower in CC genotype (45.0±7.11 ng/mL) compared to CT genotype (50.81±5.81 ng/mL) among the patients with periodontitis. The results suggest that LXA4 and c.-292T allele are associated with periodontal health. Polymorphisms in the ALOX15 gene may influence periodontal disease pathogenesis. Hence, investigation of such polymorphisms could benefit the evaluation of lipoxins role in periodontal disease.

Resumo Lipoxinas desempenham um papel importante na recuperação periodonta, portanto, a investigação do polimorfismo genético do gene da lipoxina pode fornecer informações importantes sobre o papel das lipoxinas na patogênese da doença periodontal. O objetivo deste estudo foi investigar um polimorfismo de substituição C-to-T na posição c-292 no gene ALOX15 (reticulócito-tipo 15 lipoxigenase 1) em pacientes com periodontite crônica e associar o polimorfismo com a lipoxina A4 (LXA4) do fluido gengival crevicular (FGC). Quarenta e cinco pacientes com periodontite crônica e 45 pacientes periodonalmente saudáveis foram incluídos neste estudo caso-controle. Índice de placa, índice de cálculo, índice de sangramento do sulco, profundidade de sondagem (PS) da boca toda e perda de inserção clínica (PIC) foram registrados. Amostras do FGC e de sangue foram coletadas. O FGC foi analisado quanto aos níveis de LXA4 por ensaio imunoadsorvente ligado à enzima (ELISA). A genotipagem do polimorfismo ALOX15 foi estudada por PCR. A média de LXA4 foi menor no grupo de periodontite em comparação com o grupo periodontalmente saudável. Houve uma correlação negativa entre PIC e LXA4. O genótipo CC foi maior no grupo de estudo do que no grupo controle. No grupo de estudo, a média de PIC foi significativamente menor entre os indivíduos com o genótipo CT. A média de LXA4 foi significativamente menor no genótipo CC (45,0 ± 7,11 ng / mL) em comparação com o genótipo CT (50,81 ± 5,81 ng / mL) entre os pacientes com periodontite. Os resultados sugerem que o alelo LXA4 e o alelo c-292T estão associados à saúde periodontal. Polimorfismos no gene ALOX15 podem influenciar a patogênese da doença periodontal. Assim, a investigação de tais polimorfismos pode beneficiar a avaliação do papel das lipoxinas na doença periodontal.

Effects of dexamethasone on 15-lipoxygenase expression in lungs of asthmatic rats / 中国当代儿科杂志

<p><b>OBJECTIVE</b>15-lipoxygenase (15-LO) is a prooxidant enzyme which is expressed in asthmatic lungs leading to formation of pro- and anti-inflammatory mediators. Gene expression profiling studies show the association between 15-LO and allergic asthma. This study was designed to observe the expression of 15-LO in lungs of asthmatic rats and examine the effects of dexamethasone on 15-lipoxygenase expression.</p><p><b>METHODS</b>Twenty-seven male Sprague-Dawley (SD) rats were randomly divided into three groups: control, asthma and dexamethasone (DXM) intervention. An asthma model was prepared by sensitization and challenging with ovalbumin. The production of 15-LO in lung tissue homogenates was measured using ELISA.The expression of 15-LO mRNA in lungs was determined by reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The levels of 15-LO mRNA and protein in the asthma group (0.51 ± 0.14 and 2080 ± 73 μg/mL, respectively) were lower than those in the control group (0.76 ± 0.15 and 2472 ± 106 μg/mL, respectively; P<0.01). DXM intervention increased significantly the levels of 15-LO mRNA and protein (1.02 ± 0.34 and 2562 ± 218 μg/mL) compared with the asthma group (P<0.01).</p><p><b>CONCLUSIONS</b>The production of 15-LO in lung tissues is reduced in asthmatic rats. DXM can increase the expression of 15-LO in lung tissues and thus might provide anti-inflammatory effects in asthmatic rats.</p>

15-Lipoxygenase-1 Induced by Interleukin-4 Mediates Apoptosis in Oral Cavity Cancer Cells / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In oral cavity cancer (OCC) cells, the effects of interleukin-4 (IL-4) are various according to the cell specificity. However, if IL-4 induces apoptosis on OCC cells, the mediator of this apoptosis is uncertain. Therefore, we investigated whether apoptosis of OCC cells occurs by IL-4 and whether 15-lipoxygenase-1 (15-LO-1) induced by IL-4 is the possible mediator of this apoptosis. MATERIALS AND METHODS: SCC 1483 cells were used. Flow cytometry and poly ADP-ribose polymerase cleavage were used to examine apoptosis. Western blot analysis and reverse transcription-polymerase chain reaction were used to measure 15-LO-1 protein and mRNA. RESULTS: The inhibition of cell proliferation by more than 50% was noted from 10 ng/ml of IL-4. At this dose, apoptosis was observed and this apoptosis was inhibited by 2.2 microM caffeic acid. 15-LO-1 expression was observed from the 8 hour treatment of IL-4 and apoptosis increased after the 24 hour treatment of IL-4. In this apoptosis, caspase cascade, cyclooxygenase-2, and non-steroidal anti-inflammatory drugs-activated gene-1 (NAG-1) were not involved. CONCLUSION: IL-4 induced apoptosis in SCC 1483 OCC cells and 15-LO-1 induced by IL-4 may mediate this apoptotic pathway.

Reticulocyte maturation: mitoptosis and exosome release

During the differentiation of erythroid cells, a vast program of maturation takes place, leading to decay or elimination of organelles, including the nucleus, mitochondria, ribosomes, lysosomes, endoplasmic reticulum and Golgi apparatus. During the last step of red cell maturation, remaining organelles, primarily mitochondria and ribosomes but also vestiges of others are finally cleared from the cell. This cleaning session also affects specific proteins that are partially or entirely removed from the cell surface. The interplay of the various events and their causal relationships are approached here.