Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Endogenous generation of nitro-fatty acid hybrids having dual nitrate ester (RONO₂) and nitroalkene (RNO₂) substituents.

ABSTRACT: Organic nitrate esters, long-recognized therapies for cardiovascular disorders, have not been detected biologically. We characterize in rat stomach unsaturated fatty acid nitration reactions that proceed by generation of nitro-nitrate intermediates (NO₂-ONO₂-FA) via oxygen and nitrite dependent reactions. NO₂-ONO₂-lipids represent ∼70% of all nitrated lipids in the stomach and they decay in vitro at neutral or basic pH by the loss of the nitrate ester group (-ONO₂) from the carbon backbone upon deprotonation of the α-carbon (pKa ∼7), yielding nitrate, nitrite, nitrosative species, and an electrophilic fatty acid nitroalkene product (NO₂-FA). Of note, NO₂-FA are anti-inflammatory and tissue-protective signaling mediators, which are undergoing Phase II trials for the treatment of kidney and pulmonary diseases. The decay of NO₂-ONO₂-FA occurs during intestinal transit and absorption, leading to the formation of NO₂-FA that were subsequently detected in circulating plasma triglycerides. These observations provide new insight into unsaturated fatty acid nitration mechanisms, identify nitro-nitrate ester-containing lipids as intermediates in the formation of both secondary nitrogen oxides and electrophilic fatty acid nitroalkenes, and expand the scope of endogenous products stemming from metabolic reactions of nitrogen oxides.

SUBMITTER: Fazzari M

PROVIDER: S-EPMC8049994 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Optical, Electrical and Thermal Properties of Organic⁻Inorganic Hybrids with Conjugated Polymers Based on POSS Having Heterogeneous Substituents.

Project description:Preparation of organic⁻inorganic hybrids with conventional conjugated polymers such as polyfluorene (PF) and poly(3-hexylthiophene) (P3HT) were demonstrated via the facile blending in solution by employing polyhedral oligomeric silsesquioxane (POSS) having heterogeneous alkyl substituents. From the optical measurements, it was shown that the modified POSS derivatives played a critical role in facilitating amorphous state of polymer matrices. Interestingly, although inter-strand interaction decreased after POSS addition in the hybrid films, thermal stability can be enhanced in the presence of the modified POSS with long alkyl chains. Furthermore, it was demonstrated that carrier mobilities through the hybrid film was minimally reduced by POSS. These results suggest that POSS should be a versatile building block to form hybrid with various types of polymers for enhancing durability without loss of electronic properties of organic components.

| S-EPMC6401744 | biostudies-literature

Modulation of nitro-fatty acid signaling: prostaglandin reductase-1 is a nitroalkene reductase.

Project description:Inflammation, characterized by the activation of both resident and infiltrated immune cells, is accompanied by increased production of oxidizing and nitrating species. Nitrogen dioxide, the proximal nitrating species formed under these conditions, reacts with unsaturated fatty acids to yield nitroalkene derivatives. These electrophilic products modulate protein function via post-translational modification of susceptible nucleophilic amino acids. Nitroalkenes react with Keap1 to instigate Nrf2 signaling, activate heat shock response gene expression, and inhibit NF-?B-mediated signaling, inducing net anti-inflammatory and tissue-protective metabolic responses. We report the purification and characterization of a NADPH-dependent liver enzyme that reduces the nitroalkene moiety of nitro-oleic acid, yielding the inactive product nitro-stearic acid. Prostaglandin reductase-1 (PtGR-1) was identified as a nitroalkene reductase by protein purification and proteomic studies. Kinetic measurements, inhibition studies, immunological and molecular biology approaches as well as clinical analyses confirmed this identification. Overexpression of PtGR-1 in HEK293T cells promoted nitroalkene metabolism to inactive nitroalkanes, an effect that abrogated the Nrf2-dependent induction of heme oxygenase-1 expression by nitro-oleic acid. These results situate PtGR-1 as a critical modulator of both the steady state levels and signaling activities of fatty acid nitroalkenes in vivo.

| S-EPMC3757223 | biostudies-literature

Prostaglandin E2 glyceryl ester is an endogenous agonist of the nucleotide receptor P2Y6.

Project description:Cyclooxygenase-2 catalyses the biosynthesis of prostaglandins from arachidonic acid but also the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. Previous studies identified PG-Gs as signalling molecules involved in inflammation. Thus, the glyceryl ester of prostaglandin E2, PGE2-G, mobilizes Ca2+ and activates protein kinase C and ERK, suggesting the involvement of a G protein-coupled receptor (GPCR). To identify the endogenous receptor for PGE2-G, we performed a subtractive screening approach where mRNA from PGE2-G response-positive and -negative cell lines was subjected to transcriptome-wide RNA sequencing analysis. We found several GPCRs that are only expressed in the PGE2-G responder cell lines. Using a set of functional readouts in heterologous and endogenous expression systems, we identified the UDP receptor P2Y6 as the specific target of PGE2-G. We show that PGE2-G and UDP are both agonists at P2Y6, but they activate the receptor with extremely different EC50 values of ~1 pM and ~50 nM, respectively. The identification of the PGE2-G/P2Y6 pair uncovers the signalling mode of PG-Gs as previously under-appreciated products of cyclooxygenase-2.

| S-EPMC5443783 | biostudies-literature

Characterization and quantification of endogenous fatty acid nitroalkene metabolites in human urine.

Project description:The oxidation and nitration of unsaturated fatty acids transforms cell membrane and lipoprotein constituents into mediators that regulate signal transduction. The formation of 9-NO2-octadeca-9,11-dienoic acid and 12-NO2-octadeca-9,11-dienoic acid stems from peroxynitrite- and myeloperoxidase-derived nitrogen dioxide reactions as well as secondary to nitrite disproportionation under the acidic conditions of digestion. Broad anti-inflammatory and tissue-protective responses are mediated by nitro-fatty acids. It is now shown that electrophilic fatty acid nitroalkenes are present in the urine of healthy human volunteers (9.9 ± 4.0 pmol/mg creatinine); along with electrophilic 16- and 14-carbon nitroalkenyl ?-oxidation metabolites. High resolution mass determinations and coelution with isotopically-labeled metabolites support renal excretion of cysteine-nitroalkene conjugates. These products of Michael addition are in equilibrium with the free nitroalkene pool in urine and are displaced by thiol reaction with mercury chloride. This reaction increases the level of free nitroalkene fraction >10-fold and displays a K(D) of 7.5 × 10(-6) M. In aggregate, the data indicates that formation of Michael adducts by electrophilic fatty acids is favored under biological conditions and that reversal of these addition reactions is critical for detecting both parent nitroalkenes and their metabolites. The measurement of this class of mediators can constitute a sensitive noninvasive index of metabolic and inflammatory status.

| S-EPMC3679401 | biostudies-literature

Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3.

Project description:Deep eutectic solvents (DESs) have gained attention as green and safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and β-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily reproducible protocol to isolate the product without the use of any organic solvent was established, and the recyclability of the DES mixture was successfully investigated.

| S-EPMC8111428 | biostudies-literature

4-(2-Nitro-benzene-sulfonamido)pyridinium nitrate.

Project description:There are two mol-ecules in the asymmetric unit of the title compound, C(11)H(10)N(3)O(4)S(+)·NO(3) (-). All bond distances have normal values. The C-N bond distances in the sulfonamide group [1.389 (3) and 1.382 (3) Å] may indicate slight conjugation of the sulfonamide N-atom π-electrons with those of the pyridinium ring. The crystal structure is stabilized by N-H⋯O hydrogen bonds.

| S-EPMC2959887 | biostudies-literature

4-(4-Nitro-benzene-sulfonamido)pyridinium nitrate.

Project description:A short C-N distance [1.394 (2) Å] in the title compound, C(11)H(10)N(3)O(4)S(+)·NO(3) (-), is indicative of some conjugation of the sulfonamide π electrons with those of the pyridinium ring. The crystal structure is stabilized by N-H⋯O hydrogen bonds.

| S-EPMC2959869 | biostudies-literature

Synthesis, Characterization, and Energetic Properties of Nitrate Ester Acrylate Polymer

Project description: Not available

| S-EPMC10601433 | biostudies-literature

N-Acetyl-5-chloro-3-nitro-l-tyrosine ethyl ester.

Project description:The title compound, C(13)H(15)ClN(2)O(6), was synthesized by hypochlorous acid-mediated chlorination of N-acetyl-3-nitro-l-tyrosine ethyl ester. The OH group forms an intra-molecular O-H⋯O hydrogen bond to the nitro group and the N-H group forms an inter-molecular N-H⋯O hydrogen bonds to an amide O atom, linking the mol-ecules into chains along [100]. The crystal studied was a non-merohedral twin, with a 0.907 (4):0.093 (4) domain ratio.

| S-EPMC3435836 | biostudies-literature

Synthesis of C70-fragment buckybowls bearing alkoxy substituents.

Project description:Buckybowls bearing a C70 fragment having two alkoxy groups were synthesized and their structural and optical properties were investigated by single crystal X-ray analysis and UV-vis spectroscopy. In the synthesis of dioxole derivative 5b, the regioisomer 5c was also produced. The yield of 5c was increased by increasing the reaction temperature, indicating that the rearrangement might involve the equilibrium between the Pd(IV) intermediates through C-H bond activation.

| S-EPMC7176931 | biostudies-literature