scholarly journals Knock-In Mice Expressing a 15-Lipoxygenating Alox5 Mutant Respond Differently to Experimental Inflammation Than Reported Alox5−/− Mice

Metabolites ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 698
Author(s):  
Eugenia Marbach-Breitrück ◽  
Nadine Rohwer ◽  
Carmen Infante-Duarte ◽  
Silvina Romero-Suarez ◽  
Dominika Labuz ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Disease Onset ◽  
Clinical Score ◽  
Polyenoic Fatty Acid ◽  
Loss Of Function ◽  
Dss Colitis ◽  
Oxygenase Activity ◽  
Key Enzyme ◽  
Similar Genetic Background ◽  
Experimental Inflammation

Arachidonic acid 5-lipoxygenase (ALOX5) is the key enzyme in the biosynthesis of pro-inflammatory leukotrienes. We recently created knock-in mice (Alox5-KI) which express an arachidonic acid 15-lipoxygenating Alox5 mutant instead of the 5-lipoxygenating wildtype enzyme. These mice were leukotriene deficient but exhibited an elevated linoleic acid oxygenase activity. Here we characterized the polyenoic fatty acid metabolism of these mice in more detail and tested the animals in three different experimental inflammation models. In experimental autoimmune encephalomyelitis (EAE), Alox5-KI mice displayed an earlier disease onset and a significantly higher cumulative incidence rate than wildtype controls but the clinical score kinetics were not significantly different. In dextran sodium sulfate-induced colitis (DSS) and in the chronic constriction nerve injury model (CCI), Alox5-KI mice performed like wildtype controls with similar genetic background. These results were somewhat surprising since in previous loss-of-function studies targeting leukotriene biosynthesis (Alox5−/− mice, inhibitor studies), more severe inflammatory symptoms were observed in the EAE model but the degree of inflammation in DSS colitis was attenuated. Taken together, our data indicate that these mutant Alox5-KI mice respond differently in two models of experimental inflammation than Alox5−/− animals tested previously in similar experimental setups.

scholarly journals Level of Arachidonic Acid and State of Peroxidation Processes in Patients with Aspirin-Intolerant Polypous Rhinosinusitis

2016 ◽  
Vol 23 (4) ◽  
pp. 2016410
Author(s):  
Ivanna Koshel
Keyword(s):  
Arachidonic Acid ◽  
Metabolic Pathways ◽  
Acid Metabolism ◽  
Serum Proteins ◽  
Arachidonic Acid Metabolism ◽  
Oxidative Modification ◽  
Key Enzyme ◽  
Protein Peroxidation ◽  
Genetic Block ◽  
Peroxidation Processes

The main peculiarity of aspirin-intolerant polypous rhinosinusitis pathogenesis is the presence of “genetic block” of constitutive cyclooxygenase being the key enzyme of the arachidonic acid metabolism. It justifies the necessity of studying its metabolic peculiarities.The objective of the research was to determine the level of arachidonic acid as well as the state of lipid and protein peroxidation processes in patients with aspirin-intolerant polypous rhinosinusitis.Materials and methods. The levels of arachidonic acid, malondialdehyde and oxidative modification of serum proteins were studied in 20 patients with aspirin-intolerant polypous rhinosinusitis and 7 healthy individuals.Results. Significantly elevated levels of arachidonic levels were observed. The search for alternative metabolic pathways stimulated lipid and protein peroxidation processes and led to the increase in the levels of malondialdehyde and oxidative modification of serum proteins. The peculiarities of biochemical changes indicated pro-inflammatory orientation of lipid metabolism.Conclusions. The obtained data confirmed the hypothesis of “genetic block” of the arachidonic acid metabolism as the main pathogenetic component of aspirin-intolerant polypous rhinosinusitis and allowed us to clearly interpret biochemical picture of the disease.

Aspirin Preferentially Inhibits Arachidonic Acid Metabolism In Collagen Vs. Thrombin-Stimulated Platelets

1981 ◽  
Author(s):  
D Deykin ◽  
R Vaillancourt
Keyword(s):  
High Performance Liquid Chromatography ◽  
Arachidonic Acid ◽  
Liquid Chromatography ◽  
High Performance ◽  
Acid Metabolism ◽  
Gel Filtration ◽  
Human Platelets ◽  
Arachidonic Acid Metabolism ◽  
Selective Effect ◽  
Oxygenase Activity

The purpose of this study was to compare the effect of aspirin on the release of metabolites of arachidonic acid from thrombin and collagen stimulated platelets. Human platelets were incubated with tritium-labeled arachidonic acid and then isolated by gel filtration. The labeled platelets were stimulated with varied doses of either thrombin or collagen for 15 minutes. The platelets were then pelleted and the released metabolites of arachidonic acid were separated by high-performance liquid chromatography. In experiments with aspirin, the aspirin was added 5 minutes before either thrombin or collagen. The total release of radioactivity was comparable at 15 μg/ml of collagen and 1.0 units/ml of thrombin (approximately 10% of the total) and at 100 μg/ml of collagen and 5 units/ml of thrombin (approximately 30%). Aspirin (25 μg/ml) preferentially inhibited collagen-stimulated release of radioactivity (62% inhibition of release with 15 μg/ml of collagen vs. 25% inhibition of release with 1.0 units/ml of thrombin; 54% inhibition of release with 100 μg/ml of collagen vs. 8% inhibition of release with 5.0 units/ml of thrombin). At all concentrations of collagen or thrombin, cyclo-oxygenase activity was markedly reduced by aspirin. The selective effect of aspirin on collagen reflects primarily preferential suppression of HETE formation. We conclude that aspirin inhibits the formation of both lipoxygenase and cyclooxygenase-derived products in collagen-stimulated platelets.

P152 EVALUATING THE EFFICACY OF GLUTAMATE CARBOXYPEPTIDASE II (GCPII) INHIBITORS IN “WILD-TYPE” MICE: LESSONS LEARNED FROM THE DEDICATOR OF CYTOKINESIS 2 MUTANT MOUSE

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S6-S6
Author(s):  
Diane Peters ◽  
Lauren Norris ◽  
Barbara Slusher
Keyword(s):  
Therapeutic Target ◽  
Activity Index ◽  
Disease Activity Index ◽  
Lessons Learned ◽  
Target Protein ◽  
Loss Of Function ◽  
Wild Type ◽  
Glutamate Carboxypeptidase Ii ◽  
Dss Colitis ◽  
Glutamate Carboxypeptidase

Abstract Background Glutamate carboxypeptidase II (GCPII) is highly upregulated in human IBD and is a therapeutic target under active investigation by our laboratory. We recently published that a spontaneously occurring loss-of-function mutation in dedicator of cytokinesis 2 (Dock2Hsd) that was present in commercially-purchased “wild-type” C57Bl6/NHsd mice increased their sensitivity to DSS-colitis and caused them to closely resemble human IBD with respect to GCPII. The DSS-exposed Dock2Hsd mice had significantly elevated colon GCPII activities and were sensitive to treatment with the GCPII inhibitor, 2-PMPA. We hypothesized that if colitis of the same severity were to be induced in Dock2WT mice, that they would also exhibit heightened colon GCPII activity and would be equally sensitive to 2-PMPA treatment. Methods DSS-colitis was induced in weight-, age- and gender-matched C57Bl/6NHsd mice (Dock2Hsd and Dock2WT). Increasing concentrations of DSS were utilized (2.5%-4.0%) and disease activity index was monitored daily. Mice received once daily treatment with vehicle or GCPII inhibitor 2-PMPA (IP). Results With increased DSS concentrations (4%), a severe colitis could be established in the Dock2WT mice which closely resembled the disease seen in Dock2Hsd mice induced with 2.5% DSS. Interestingly, despite similarity in DAI scores and disease progression, the GCPII activity in colons of Dock2WT mice (4% DSS) remained significantly lower than that of Dock2Hsd mice (2.5% DSS) (p<0.001, t-test). Further, while 2-PMPA was effective in both groups, higher systemic doses were required in the IBD-resistant Dock2WT mice. Conclusions Following identification that the spontaneously occurring mutation Dock2Hsd influences murine DSS-colitis sensitivity and alters the activity of our therapeutic target protein, GCPII, in the colon, we sought to re-establish our DSS model using Dock2WT mice. While we were successfully able to recapitulate disease severity in the Dock2WT mice by increasing the DSS concentration from 2.5% to 4%, the underlying disease biology was not conserved. Despite having comparable DAI scores at study termination, Dock2WT mice had decreased GCPII activity in their colons relative to Dock2Hsd mice and were less sensitive to inhibition with the GCPII inhibitor, 2-PMPA. These data caution that target protein expression must be verified even with subtle changes to experimental method when utilizing the DSS-colitis model.

Arachidonic acid ω-hydroxylase CYP4A11: inter-ethnic variations in the 8590T>C loss-of-function variant

2011 ◽  
Vol 39 (2) ◽  
pp. 1503-1508 ◽  
Author(s):  
Christian Lacks Lino Cardenas ◽  
Aurore Devos ◽  
Aminata Toure ◽  
Jaime Cardenas Garcia ◽  
Abderraouf Kenani ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Loss Of Function ◽  
Ethnic Variations

scholarly journals AtDAT1 is a key enzyme of D-amino acid stimulated ethylene production in Arabidopsis thaliana

2019 ◽  
Author(s):  
Juan Suarez ◽  
Claudia Hener ◽  
Vivien-Alisa Lehnhardt ◽  
Sabine Hummel ◽  
Mark Stahl ◽  
...  
Keyword(s):  
Ethylene Production ◽  
Biochemical Characterization ◽  
Reciprocal Relation ◽  
Loss Of Function ◽  
Working Models ◽  
Specific Effects ◽  
Starting Point ◽  
Natural Variants ◽  
Key Enzyme ◽  
The Impact

AbstractD-enantiomers of proteinogenic amino acids (D-AAs) are found ubiquitously, but the knowledge about their metabolism and functions in plants is scarce. A long forgotten phenomenon in this regard is the D-AA-stimulated ethylene production in plants. As a starting point to investigate this effect the Arabidopsis accession Landsberg erecta (Ler) got into focus as it was found defective in metabolizing D-AAs. Combining genetics and molecular biology of T-DNA lines and natural variants together with biochemical and physiological approaches we could identify AtDAT1 as a major D-AA transaminase in Arabidopsis. Atdat1 loss-of-function mutants and Arabidopsis accessions with defective AtDAT1 alleles were not able to produce D-Ala, D-Glu and L-Met, the metabolites of D-Met, anymore. This result corroborates the biochemical characterization of AtDAT1, which showed highest activity using D-Met as substrate. Germination of seedlings in light and dark led to enhanced growth inhibition of atdat1 mutants on D-Met. Ethylene measurements revealed an enhanced D-AA stimulated ethylene production in these mutants. According to initial working models of this phenomenon D-Met is preferentially malonylated instead of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). This decrease of ACC degradation should then lead to the increase of ethylene production. We could observe in our studies a reciprocal relation of malonylated methionine and ACC upon D-Met application and even significantly more malonyl-methionine in atdat1 mutants. Unexpectedly, the malonyl-ACC levels did not differ between mutants and wild type in these experiments. With AtDAT1, the first central enzyme of plant D-AA metabolism was characterized biochemically and physiologically. The specific effects of D-Met on ACC metabolization, ethylene production and plant development of dat1 mutants unraveled the impact of AtDAT1 on these processes, but they are not in full accordance to previous working models. Instead, our results imply the influence of additional candidate factors or processes on D-AA-stimulated ethylene production which await to be uncovered.

scholarly journals Evaluation of Cyclo-Oxygenase Pathway in Platelets of the Newborn

1977 ◽  
Author(s):  
D. G. Corby ◽  
W. C. Goad ◽  
J. Barber ◽  
T. P. O’Barr
Keyword(s):  
Arachidonic Acid ◽  
Thin Layer ◽  
Cord Blood ◽  
Newborn Infant ◽  
Blood Samples ◽  
Release Reaction ◽  
Oxygenase Activity ◽  
Arachidonic Acid Metabolites ◽  
Acid Metabolites ◽  
External Stimuli

A possible deficiency of cyclo-oxygenase in platelets of the newborn infant has been considered as an explanation for their impaired aggregation to stimuli which function by promoting the release of ADP. (Corby and Zuck, Thrombos. and Haemostas., USA 36:201–207, 1976). Cyclo-oxygenase activity was evaluated in washed platelets from paired mother and cord blood samples by monitoring the incorporation of radioactivity into metabolites during incubation with (1-14C) arachidonic acid. Platelets from both the mothers and newborns showed normal aggregation to arachidonic acid. Thin layer radiochromatograms of methylated incubation products were essentially identical. Three main peaks of radioactivity, which corresponded to identified arachidonic acid metabolites, were noted (Malmsten et al. Proc. Natl. Acad. Sei., USA, 72:1446–1450, 1975). Platelets from mothers and newborns incorporated similar amounts of radioactivity into 8-(1-hydroxy-3-oxopropy1)-9,12L-dihydroxy-5-10-heptadecadienoic acid (PHD) and 12L-hydroxy-5,8,10-heptadecatrienoic acid (HHT). Since these two compounds are derived from the endoperoxide prostaglandin G2(PGG2), which is believed to initiate the release reaction, the pathway leading from arachidonic acid to PGG2 is probably fully developed in platelets of the newborn infant. It may be speculated that the lack of response by these platelets to external stimuli is related to either the availability or the formation of metabolically available arachidonic acid.

scholarly journals Fission Yeast Methylenetetrahydrofolate Reductase Ensures Mitotic and Meiotic Chromosome Segregation Fidelity

2021 ◽  
Vol 22 (2) ◽  
pp. 639
Author(s):  
Kim Kiat Lim ◽  
Hwei Yee Teo ◽  
Yuan Yee Tan ◽  
Yi Bing Zeng ◽  
Ulysses Tsz Fung Lam ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Methylenetetrahydrofolate Reductase ◽  
Meiotic Chromosome ◽  
Genetic Material ◽  
Loss Of Function ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Sporulation Efficiency ◽  
Key Enzyme ◽  
Mitosis And Meiosis

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate metabolic pathway, and its loss of function through polymorphisms is often associated with human conditions, including cancer, congenital heart disease, and Down syndrome. MTHFR is also required in the maintenance of heterochromatin, a crucial determinant of genomic stability and precise chromosomal segregation. Here, we characterize the function of a fission yeast gene met11+, which encodes a protein that is highly homologous to the mammalian MTHFR. We show that, although met11+ is not essential for viability, its disruption increases chromosome missegregation and destabilizes constitutive heterochromatic regions at pericentromeric, sub-telomeric and ribosomal DNA (rDNA) loci. Transcriptional silencing at these sites were disrupted, which is accompanied by the reduction in enrichment of histone H3 lysine 9 dimethylation (H3K9me2) and binding of the heterochromatin protein 1 (HP1)-like Swi6. The met11 null mutant also dominantly disrupts meiotic fidelity, as displayed by reduced sporulation efficiency and defects in proper partitioning of the genetic material during meiosis. Interestingly, the faithful execution of these meiotic processes is synergistically ensured by cooperation among Met11, Rec8, a meiosis-specific cohesin protein, and the shugoshin protein Sgo1, which protects Rec8 from untimely cleavage. Overall, our results suggest a key role for Met11 in maintaining pericentromeric heterochromatin for precise genetic inheritance during mitosis and meiosis.

scholarly journals DrosophilaMutant Model of Parkinson’s Disease Revealed an Unexpected Olfactory Performance: Morphofunctional Evidences

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Francescaelena De Rose ◽  
Valentina Corda ◽  
Paolo Solari ◽  
Patrizia Sacchetti ◽  
Antonio Belcari ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Disease Onset ◽  
Model Organism ◽  
Fruit Fly ◽  
Specific Model ◽  
Loss Of Function ◽  
Olfactory Sensilla ◽  
Olfactory Stimuli ◽  
Clinical Triad

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases characterized by the clinical triad: tremor, akinesia, and rigidity. Several studies have suggested that PD patients show disturbances in olfaction as one of the earliest, nonspecific nonmotor symptoms of disease onset. We sought to use the fruit flyDrosophila melanogasteras a model organism to explore olfactory function in LRRKloss-of-functionmutants, which was previously demonstrated to be a useful model for PD. Surprisingly, our results showed that the LRRK mutant, compared to the wild flies, presents a dramatic increase in the amplitude of the electroantennogram responses and this is coupled with a higher number of olfactory sensilla. In spite of the above reported results, the behavioural response to olfactory stimuli in mutant flies is impaired compared to that obtained in wild type flies. Thus, behaviour modifications and morphofunctional changes in the olfaction of LRRKloss-of-functionmutants might be used as an index to explore the progression of parkinsonism in this specific model, also with the aim of studying and developing new treatments.

scholarly journals The diacylglycerols dioctanoylglycerol and oleoylacetylglycerol enhance prostaglandin synthesis by inhibition of the lysophosphatide acyltransferase

1987 ◽  
Vol 247 (3) ◽  
pp. 773-777 ◽  
Author(s):  
M Goppelt-Strübe ◽  
H J Pfannkuche ◽  
D Gemsa ◽  
K Resch
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Direct Interaction ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Kinase C ◽  
Key Enzyme ◽  
Free Arachidonic Acid

Prostanoids are synthesized by resident macrophages upon stimulation with diacylglycerols. Oleoylacetylglycerol and dioctanoylglycerol induced prostaglandin E and thromboxane synthesis in a time- and concentration-dependent manner. Both diacylglycerols inhibited the lysophosphatide acyltransferase, which is the key enzyme in the reacylation of arachidonic acid. By this mechanism the pool of free arachidonic acid available for prostanoid synthesis is increased. Both diacylglycerols were able to inhibit the membrane-bound lysophosphatide acyltransferase by a direct interaction independent of protein kinase C. Thus lysophosphatide acyltransferase could be shown to be a new target of these diacylglycerols, known as activators of protein kinase C.

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