Oleamide synthesizing activity from rat kidney: identification as cytochrome c

Enhanced diagnosis and prognosis of severe alcoholic hepatitis using novel metabolomic biomarkers

AIM

Differentiating alcoholic hepatitis (AH) from acute decompensation of alcoholic cirrhosis (DC) is challenging, as the presentation and biochemistry are similar. We aimed to identify potential metabolomic biomarkers to differentiate between AH and DC, and to predict short-term mortality.

METHODS

We included consecutive biopsy proven AH and DC patients, which were managed according to current guidelines and followed up until the end of the study. Untargeted metabolomics was assessed in all patients at baseline. Specific analyses were successively performed to identify potential biomarkers, which were further semi-quantitatively analysed against relevant clinical endpoints.

RESULTS

Thirty-four patients with AH and 37 with DC were included. UHPLC-MS analysis identified 83 molecules potentially differentiating between AH and DC. C16-Sphinganine-1P (S1P) was the most increased, whereas Prostaglandin E2 (PGE2) was the most decreased. The PGE2/S1P ratio < 1.03 excellently discriminates between AH and DC: AUC 0.965 (p < 0.001), Se 90%, Sp 100%, PPV 0.91, NPV 1, and diagnostic accuracy 95%. This ratio is not influenced by the presence of infection (AUC 0.967 vs. 0.962), correlates with the Lille score at 7 days (r = -0.60; P = 0.022) and tends to be lower in corticosteroid non-responders as compared with patients who responded [0.85(±0.02) vs. 0.89(±0.05), P = 0.069]. Additionally, decreased ursodeoxycholic acid levels are correlated with MELD and Maddrey scores and predict mortality with a 77.27% accuracy (NPV = 100%).

CONCLUSION

This study suggests the PGE2 (decreased)/S1P (increased) ratio as a biomarker to differentiate AH from DC. The study also finds that low levels of ursodeoxycholic acid could predict increased mortality in AH.

MGAT2 inhibitor decreases liver fibrosis and inflammation in murine NASH models and reduces body weight in human adults with obesity

Monoacylglycerol acyltransferase 2 (MGAT2) is an important enzyme highly expressed in the human small intestine and liver for the regulation of triglyceride absorption and homeostasis. We report that treatment with BMS-963272, a potent and selective MGAT2 inhibitor, decreased inflammation and fibrosis in CDAHFD and STAM, two murine nonalcoholic steatohepatitis (NASH) models. In high-fat-diet-treated cynomolgus monkeys, in contrast to a selective diacylglycerol acyltransferase 1 (DGAT1) inhibitor, BMS-963272 did not cause diarrhea. In a Phase 1 multiple-dose trial of healthy human adults with obesity (NCT04116632), BMS-963272 was safe and well tolerated with no treatment discontinuations due to adverse events. Consistent with the findings in rodent models, BMS-963272 elevated plasma long-chain dicarboxylic acid, indicating robust pharmacodynamic biomarker modulation; increased gut hormones GLP-1 and PYY; and decreased body weight in human subjects. These data suggest MGAT2 inhibition is a promising therapeutic opportunity for NASH, a disease with high unmet medical needs.

GC/MS Analysis, Antioxidant Activity, and Antimicrobial Effect of Pelargonium peltatum (Geraniaceae)

In recent years, the increase in antibiotic resistance demands searching for new compounds with antimicrobial activity. Phytochemicals found in plants offer an alternative to this problem. The genus Pelargonium contains several species; some have commercial use in traditional medicine such as P. sinoides, and others such as P. peltatum are little studied but have promising potential for various applications such as phytopharmaceuticals. In this work, we characterized the freeze-dried extracts (FDEs) of five tissues (root, stem, leaf, and two types of flowers) and the ethyl acetate fractions from leaf (Lf-EtOAc) and flower (Fwr-EtOAc) of P. peltatum through the analysis by thin-layer chromatography (T.L.C.), gas chromatography coupled to mass spectrometry (GC-MS), phytochemicals quantification, antioxidant capacity, and antimicrobial activity. After the first round of analysis, it was observed that the FDE-Leaf and FDE-Flower showed higher antioxidant and antimicrobial activities compared to the other FDEs, for which FDE-Leaf and FDE-Flower were fractionated and analyzed in a second round. The antioxidant activity determined by ABTS showed that Lf-EtOAc and Fwr-EtOAc had the lowest IC₅₀ values with 27.15 ± 1.04 and 28.11 ± 1.3 µg/mL, respectively. The content of total polyphenols was 264.57 ± 7.73 for Lf-EtOAc and 105.39 ± 4.04 mg G.A./g FDE for Fwr-EtOAc. Regarding the content of flavonoid, Lf-EtOAc and Fw-EtOAc had the highest concentration with 34.4 ± 1.06 and 29.45 ± 1.09 mg Q.E./g FDE. In addition, the minimum inhibitory concentration (M.I.C.) of antimicrobial activity was evaluated: Lf-EtOAc and Fwr-EtOAc were effective at 31.2 µg/mL for Staphylococcus aureus and 62.5 µg/mL for Salmonella enterica, while for the Enterococcus feacalis strain, Fwr-EtOAc presented 31.2 µg/mL of M.I.C. According to the GC-MS analysis, the main compounds were 1,2,3-Benzenetriol (Pyrogallol), with 77.38% of relative abundance in the Lf-EtOAc and 71.24% in the Fwr-EtOAc, followed by ethyl gallate (13.10%) in the Fwr-EtOAc and (Z)-9-Octadecenamide (13.63% and 6.75%) in both Lf-EtOAc and Fwr-EtOAc, respectively.

Extraction and Characterization of the Polar Lipid Fraction of Blackberry and Passion Fruit Seeds Oils Using Supercritical Fluid Extraction

The study of the phytochemical composition of seed oils is of upmost importance for the food and cosmetic industries, mainly considering their associated biological properties. Extraction of seed oils using supercritical fluids (SFE) is an ecological and green alternative to conventional extraction processes since it is able to provide with potent bioactive extracts, avoiding degradation and transformation of the compounds present originally in the raw material. The objective of the present work was the extraction of pure fractions of polar lipids and their chemical characterization using chromatographic techniques such as GC-MS and LC-DAD-MS/MS of blackberry (Rubus glaucus) and passion fruit (Passiflora edulis) seed oils extracted by supercritical carbon dioxide. Oleamides derived from oleic acid were identified as the main compounds in both samples; in particular, 9-octadecenamide was the major identified oleamide. Besides, the extract obtained from passion fruit showed to be a source of linoleic acid, while the SFE extract from blackberry presented important concentrations of vanillin. The chemical composition of these seed oils can be of high interest for their further use in cosmetics and food industry.

Metabonomic analysis of plasma biochemical changes in pyrexia rats after treatment with Gegenqinlian decoction, aspirin and itraconazole by UHPLC-FT-ICR-MS

A metabonomic approach involving an ultrahigh-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR-MS) was used to investigate the changes in the endogenous metabolites in the plasma of rats with yeast-induced pyrexia treated with Gegenqinlian decoction (GQLD), aspirin and itraconazole. The differences in the small molecule profiles of treatment using traditional Chinese medicine, etiological treatment and symptomatic treatment were elucidated. Thirty-six plasma metabolites were identified or putatively identified, and the effects of the three medicines on the thirty-six metabolites were studied. Their metabolic pathways indicated that GQLD, aspirin and itraconazole ameliorated the rats with yeast-induced pyrexia predominantly by regulating the metabolisms of phospholipid, sphingolipid, fatty acid oxidation, fatty acid amides, amino acid and glycerolipid in vivo. The pharmacodynamics and metabonomic results showed that the three medicines exhibited the therapeutic effects on pyrexia by regulating the perturbations of multiple metabolisms. The study provided a scientific basis for an in-depth understanding of the therapeutic effects of GQLD, aspirin and itraconazole on rats with yeast-induced pyrexia.

•

A UHPLC-FT-ICR-MS metabonomic approach was developed to study the anti-pyrexia effect of GQLD, aspirin and itraconazole.

•

Traditional Chinese medicine treatment, etiological treatment and symptomatic treatment were used for anti-pyrexia.

•

The effects of the three medicines on the thirty-six plasma metabolites were revealed.

•

The study provided a scientific basis for understanding the therapeutic effects of the three medicines on pyrexia rats.

Primary fatty amides in plasma associated with brain amyloid burden, hippocampal volume, and memory in the European Medical Information Framework for Alzheimer's Disease biomarker discovery cohort

Introduction:

A critical and as-yet unmet need in Alzheimer’s disease (AD) is the discovery of peripheral small molecule biomarkers. Given that brain pathology precedes clinical symptom onset, we set out to test whether metabolites in blood associated with pathology as indexed by cerebrospinal fluid (CSF) AD biomarkers.

Methods:

This study analyzed 593 plasma samples selected from the European Medical Information Framework for Alzheimer’s Disease Multimodal Biomarker Discovery study, of individuals who were cognitively healthy (n = 242), had mild cognitive impairment (n = 236), or had AD-type dementia (n = 115). Logistic regressions were carried out between plasma metabolites (n = 883) and CSF markers, magnetic resonance imaging, cognition, and clinical diagnosis.

Results:

Eight metabolites were associated with amyloid b and one with t-tau in CSF, these were primary fatty acid amides (PFAMs), lipokines, and amino acids. From these, PFAMs, glutamate, and aspartate also associated with hippocampal volume and memory.

Discussion:

PFAMs have been found increased and associated with amyloid b burden in CSF and clinical measures.

Skeletal muscle interstitial fluid metabolomics at rest and associated with an exercise bout: application in rats and humans

Blood or biopsies are often used to characterize metabolites that are modulated by exercising muscle. However, blood has inputs derived from multiple tissues, biopsies cannot discriminate between secreted and intracellular metabolites, and their invasive nature is challenging for frequent collections in sensitive populations (e.g., children and pregnant women). Thus, minimally invasive approaches to interstitial fluid (IF) metabolomics would be valuable. A catheter was designed to collect IF from the gastrocnemius muscle of acutely anesthetized adult male rats at rest or immediately following 20 min of exercise (~60% of maximal O₂ uptake). Nontargeted, gas chromatography-time-of-flight mass spectrometry analysis was used to detect 299 metabolites, including nonannotated metabolites, sugars, fatty acids, amino acids, and purine metabolites and derivatives. Just 43% of all detected metabolites were common to IF and blood plasma, and only 20% of exercise-modified metabolites were shared in both pools, highlighting that the blood does not fully reflect the metabolic outcomes in muscle. Notable exercise patterns included increased IF amino acids (except leucine and isoleucine), increased α-ketoglutarate and citrate (which may reflect tricarboxylic acid cataplerosis or shifts in nonmitochondrial pathways), and higher concentration of the signaling lipid oleamide. A preliminary study of human muscle IF was conducted using a 20-kDa microdialysis catheter placed in the vastus lateralis of five healthy adults at rest and during exercise (65% of estimated maximal heart rate). Approximately 70% of commonly detected metabolites discriminating rest vs. exercise in rats were also changed in exercising humans. Interstitium metabolomics may aid in the identification of molecules that signal muscle work (e.g., exertion and fatigue) and muscle health.

Composition of the epicuticular waxes coating the adaxial side of Phyllostachys aurea leaves: Identification of very-long-chain primary amides

The present study presents comprehensive chemical analyses of cuticular wax mixtures of the bamboo Phyllostachys aurea. The epicuticular and intracuticular waxes were sampled selectively from the adaxial side of leaves on young and old plants and investigated by gas chromatography-mass spectrometry and flame ionization detection. The epi- and intracuticular layers on young and old leaves had wax loads ranging from 1.7 μg/cm(2) to 1.9 μg/cm(2). Typical very-long-chain aliphatic wax constituents were found with characteristic chain length patterns, including alkyl esters (primarily C48), alkanes (primarily C29), fatty acids (primarily C28 and C16), primary alcohols (primarily C28) and aldehydes (primarily C30). Alicyclic wax components were identified as tocopherols and triterpenoids, including substantial amounts of triterpenoid esters. Alkyl esters, alkanes, fatty acids and aldehydes were found in greater amounts in the epicuticular layer, while primary alcohols and most terpenoids accumulated more in the intracuticular wax. Alkyl esters occurred as mixtures of metamers, combining C20 alcohol with various acids into shorter ester homologs (C36C40), and a wide range of alcohols with C22 and C24 acids into longer esters (C42C52). Primary amides were identified, with a characteristic chain length profile peaking at C30. The amides were present exclusively in the epicuticular layer and thus at or near the surface, where they may affect plant-herbivore or plant-pathogen interactions.

A single aldehyde group can serve as a structural element for recognition by transmembrane protein CD36

Transmembrane protein CD36 is considered to bind its distinct ligands such as long-chain fatty acids primarily by recognizing their terminal carboxyl moiety. In this study, we provide evidence that long-chain fatty aldehydes, such as oleic aldehyde, can be recognized by CD36. We suggest that a single aldehyde group may also serve as one of the structural elements recognizable by CD36.

Subtle Change in the Charge Distribution of Surface Residues May Affect the Secondary Functions of Cytochrome c

Although the primary function of cytochrome c (cyt c) is electron transfer, the protein caries out an additional secondary function involving its interaction with membrane cardiolipin (CDL), its peroxidase activity, and the initiation of apoptosis. Whereas the primary function of cyt c is essentially conserved, its secondary function varies depending on the source of the protein. We report here a detailed experimental and computational study, which aims to understand, at the molecular level, the difference in the secondary functions of cyt c obtained from horse heart (mammalian) and Saccharomyces cerevisiae (yeast). The conformational landscape of cyt c has been found to be heterogeneous, consisting of an equilibrium between the compact and extended conformers as well as the oligomeric species. Because the determination of relative populations of these conformers is difficult to obtain by ensemble measurements, we used fluorescence correlation spectroscopy (FCS), a method that offers single-molecule resolution. The population of different species is found to depend on multiple factors, including the protein source, the presence of CDL and urea, and their concentrations. The complex interplay between the conformational distribution and oligomerization plays a crucial role in the variation of the pre-apoptotic regulation of cyt c observed from different sources. Finally, computational studies reveal that the variation in the charge distribution at the surface and the charge reversal sites may be the key determinant of the conformational stability of cyt c.

Altered plasma lysophosphatidylcholines and amides in non-obese and non-diabetic subjects with borderline-to-moderate hypertriglyceridemia: a case-control study

Hypertriglyceridemia (HTG) is a risk factor for atherosclerotic cardiovascular disease (CVD). We investigated alterations in plasma metabolites associated with borderline-to-moderate HTG (triglycerides (TG) 150-500 mg/dL). Using UPLC-LTQ-Orbitrap mass spectrometry analysis, the metabolomics profiles of 111 non-diabetic and non-obese individuals with borderline-to-moderate HTG were compared with those of 111 age- and sex-matched controls with normotriglyceridemia (NTG, TG <150 mg/dL). When compared to the NTG control group, the HTG group exhibited higher plasma levels of lysophosphatidylcholines (lysoPCs), including C14:0 (q = 0.001) and C16:0 (q = 1.8E-05), and several amides, including N-ethyldodecanamide (q = 2.9E-05), N-propyldodecanamide (q = 3.5E-05), palmitoleamide (q = 2.9E-06), and palmitic amide (q = 0.019). The metabolomic profiles of the HTG group also exhibited lower plasma levels of cis-4-octenedioic acid (q<1.0E-9) and docosanamide (q = 0.002) compared with those of the NTG controls. LysoPC 16:0 and palmitoleamide emerged as the primary metabolites able to discriminate the HTG group from the NTG group in a partial least-squares discriminant analysis and were positively associated with the fasting triglyceride levels. We identified alterations in lysoPCs, amides, and cis-4-octenedioic acid among non-diabetic and non-obese individuals with borderline-to-moderate HTG. These results provide novel insights into the metabolic alterations that occur in the early metabolic stages of HTG. This information may facilitate the design of early interventions to prevent disease progression.

Oleamide activates peroxisome proliferator-activated receptor gamma (PPARγ) in vitro

Background

Oleamide (ODA) is a fatty acid primary amide first identified in the cerebrospinal fluid of sleep-deprived cats, which exerts effects on vascular and neuronal tissues, with a variety of molecular targets including cannabinoid receptors and gap junctions. It has recently been reported to exert a hypolipidemic effect in hamsters. Here, we have investigated the nuclear receptor family of peroxisome proliferator-activated receptors (PPARs) as potential targets for ODA action.

Results

Activation of PPARα, PPARβ and PPARγ was assessed using recombinant expression in Chinese hamster ovary cells with a luciferase reporter gene assay. Direct binding of ODA to the ligand binding domain of each of the three PPARs was monitored in a cell-free fluorescent ligand competition assay. A well-established assay of PPARγ activity, the differentiation of 3T3-L1 murine fibroblasts into adipocytes, was assessed using an Oil Red O uptake-based assay. ODA, at 10 and 50 μM, was able to transactivate PPARα, PPARβ and PPARγ receptors. ODA bound to the ligand binding domain of all three PPARs, although complete displacement of fluorescent ligand was only evident for PPARγ, at which an IC₅₀ value of 38 μM was estimated. In 3T3-L1 cells, ODA, at 10 and 20 μM, induced adipogenesis.

Conclusions

We have, therefore, identified a novel site of action of ODA through PPAR nuclear receptors and shown how ODA should be considered as a weak PPARγ ligand in vitro.

Metabonomic profiles discriminate hepatocellular carcinoma from liver cirrhosis by ultraperformance liquid chromatography-mass spectrometry

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and usually develops in patients with liver cirrhosis (LC). Biomarkers that discriminate HCC from LC are important but are limited. In the present study, an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS)-based metabonomics approach was used to characterize serum profiles from HCC (n = 82), LC (n = 48), and healthy subjects (n = 90), and the accuracy of UPLC-MS profiles and alpha-fetoprotein (AFP) levels were compared for their use in HCC diagnosis. By multivariate data and receiver operating characteristic curves analysis, metabolic profiles were capable of discriminating not only patients from the controls but also HCC from LC with 100% sensitivity and specificity. Thirteen potential biomarkers were identified and suggested that there were significant disturbances of key metabolic pathways, such as organic acids, phospholipids, fatty acids, bile acids, and gut flora metabolism, in HCC patients. Canavaninosuccinate was first identified as a metabolite that exhibited a significant decrease in LC and an increase in HCC. In addition, glycochenodeoxycholic acid was suggested to be an important indicator for HCC diagnosis and disease prognosis. UPLC-MS signatures, alone or in combination with AFP levels, could be an efficient and convenient tool for early diagnosis and screening of HCC in high-risk populations.

Primary fatty acid amide metabolism: conversion of fatty acids and an ethanolamine in N18TG2 and SCP cells

Primary fatty acid amides (PFAM) are important signaling molecules in the mammalian nervous system, binding to many drug receptors and demonstrating control over sleep, locomotion, angiogenesis, and many other processes. Oleamide is the best-studied of the primary fatty acid amides, whereas the other known PFAMs are significantly less studied. Herein, quantitative assays were used to examine the endogenous amounts of a panel of PFAMs, as well as the amounts produced after incubation of mouse neuroblastoma N(18)TG(2) and sheep choroid plexus (SCP) cells with the corresponding fatty acids or N-tridecanoylethanolamine. Although five endogenous primary amides were discovered in the N(18)TG(2) and SCP cells, a different pattern of relative amounts were found between the two cell lines. Higher amounts of primary amides were found in SCP cells, and the conversion of N-tridecanoylethanolamine to tridecanamide was observed in the two cell lines. The data reported here show that the N(18)TG(2) and SCP cells are excellent model systems for the study of PFAM metabolism. Furthermore, the data support a role for the N-acylethanolamines as precursors for the PFAMs and provide valuable new kinetic results useful in modeling the metabolic flux through the pathways for PFAM biosynthesis and degradation.

N-acylethanolamines as novel alcohol dehydrogenase 3 substrates

N-acylethanolamines (NAEs) are members of the fatty acid amide family. The NAEs have been proposed to serve as metabolic precursors to N-acylglycines (NAGs). The sequential oxidation of the NAEs by an alcohol dehydrogenase and an aldehyde dehydrogenase would yield the N-acylglycinals and/or the NAGs. Alcohol dehydrogenase 3 (ADH3) is one enzyme that might catalyze this reaction. To define a potential role for ADH3 in NAE catabolism, we synthesized a set of NAEs and evaluated these as ADH3 substrates. NAEs were oxidized by ADH3, yielding the N-acylglycinals as the product. The (V/K)(app) values for the NAEs included here were low relative to cinnamyl alcohol. Our data show that the NAEs can serve as alcohol dehydrogenase substrates.

Deciphering the mechanism(s) of action of natural products: analgesic peroxide oil as example

BACKGROUND

There are multiple reports of natural products having therapeutic effect. In an era of evidence-based medicine, clinical trials inform clinical decisions regarding use of the product, but prevailing preference is to identify and use a single 'active ingredient'. Yet, the clinical benefit of a natural product might derive from the fortuitous combination of its multiple components. Therefore, the elucidation of the mechanism(s) of action of natural products is important, but presents significant challenges. This article examines this issue using peroxide oil (essential oxygen oil) as an illustrative example.

OBJECTIVE

To review the published literature of a natural product in an effort to elucidate postulated mechanism(s) of action of a complex mixture.

METHODS

The clinical and preclinical literature was reviewed from the perspective of its contribution to elucidating a mechanism of analgesic action of a natural product.

RESULTS

Peroxide oil contains ingredients that are associated with analgesic mechanisms, such inhibition of lipid peroxidation and arachidonic acid metabolism and non-opioid, glibenclamide-sensitive receptor-mediated and K(ATP) -NO-cGMP channel pathways.

CONCLUSION

Although its exact mechanism remains unknown, peroxide oil provides an example of how a natural product can be evaluated for plausible mechanistic explanation of its purported therapeutic efficacy. Such an approach seems valuable, since, as in this case, the constituents appear to contribute in an additive or synergistic manner, something not possible with a single substance.

Binding of imidazole to the heme of cytochrome c1 and inhibition of the bc1 complex from Rhodobacter sphaeroides: I. Equilibrium and modeling studies

We have used imidazole (Im) and N-methylimidazole (MeIm) as probes of the heme-binding cavity of membrane-bound cytochrome (cyt) c(1) in detergent-solubilized bc(1) complex from Rhodobacter sphaeroides. Imidazole binding to cyt c(1) substantially lowers the midpoint potential of the heme and fully inhibits bc(1) complex activity. Temperature dependences showed that binding of Im (K(d) approximately 330 microM, 25 degrees C, pH 8) is enthalpically driven (DeltaH(0) = -56 kJ/mol, DeltaS(0) = -121 J/mol/K), whereas binding of MeIm is 30 times weaker (K(d) approximately 9.3 mM) and is entropically driven (DeltaH(0) = 47 kJ/mol, DeltaS(0)(o) = 197 J/mol/K). The large enthalpic and entropic contributions suggest significant structural and solvation changes in cyt c(1) triggered by ligand binding. Comparison of these results with those obtained previously for soluble cyts c and c(2) suggested that Im binding to cyt c(1) is assisted by formation of hydrogen bonds within the heme cleft. This was strongly supported by molecular dynamics simulations of Im adducts of cyts c, c(2), and c(1), which showed hydrogen bonds formed between the N(delta)H of Im and the cyt c(1) protein, or with a water molecule sequestered with the ligand in the heme cleft.

In vitro synthesis of arachidonoyl amino acids by cytochrome c

Arachidonoyl amino acids are a class of endogenous lipid messengers that are expressed in the mammalian central nervous system and peripherally. While several of their prominent pharmacologic effects have been documented, the mechanism by which arachidonoyl amino acids are biosynthesized has not been defined. We have previously observed that the mitochondrial protein, cytochrome c, is capable of catalyzing the formation of the prototypic arachidonoyl amino acid, arachidonoyl glycine, utilizing arachidonoyl CoA and glycine as substrates, in the presence of hydrogen peroxide. Here we report that cytochrome c is similarly able to catalyze the formation of N-arachidonoyl serine, N-arachidonoyl alanine, and N-arachidonoyl gamma aminobutyric acid from arachidonoyl CoA and the respective amino acids. The identities of the arachidonoyl amino acid products were verified by mass spectral fragmentation pattern analysis. The synthetic reactions exhibited Michaelis-Menten kinetics and continued favorably at physiologic temperature and pH. Spectral data indicate that both cytochrome c protein structure and a +3 heme iron oxidation state are required for the reaction mechanism to proceed optimally. Reactions designed to catalyze the formation of N-arachidonoyl dopamine were not efficient due to the rapid oxidation of dopamine substrate by hydrogen peroxide, consuming both reactants. Finally, under standard assay conditions, arachidonoyl CoA and ethanolamine were found to react spontaneously to form anandamide, independent of cytochrome c and hydrogen peroxide. Accordingly, it was not possible to demonstrate a potential role for cytochrome c in the biosynthetic mechanism for either arachidonoyl dopamine or anandamide. However, the ability of cytochrome c to effectively catalyze the formation of N-arachidonoyl serine, N-arachidonoyl alanine, and N-arachidonoyl gamma aminobutyric acid in vitro highlights its potential role for the generation of these lipid messengers in vivo.

Cytochrome c/cardiolipin relations in mitochondria: a kiss of death

Recently, phospholipid peroxidation products gained a reputation as key regulatory molecules and participants in oxidative signaling pathways. During apoptosis, a mitochondria-specific phospholipid, cardiolipin (CL), interacts with cytochrome c (cyt c) to form a peroxidase complex that catalyzes CL oxidation; this process plays a pivotal role in the mitochondrial stage of the execution of the cell death program. This review is focused on redox mechanisms and essential structural features of cyt c's conversion into a CL-specific peroxidase that represent an interesting and maybe still unique example of a functionally significant ligand change in hemoproteins. Furthermore, specific characteristics of CL in mitochondria--its asymmetric transmembrane distribution and mechanisms of collapse, the regulation of its synthesis, remodeling, and fatty acid composition--are given significant consideration. Finally, new concepts in drug discovery based on the design of mitochondria-targeted inhibitors of cyt c/CL peroxidase and CL peroxidation with antiapoptotic effects are presented.

Biosynthesis, degradation and pharmacological importance of the fatty acid amides

The identification of two biologically active fatty acid amides, N-arachidonoylethanolamine (anandamide) and oleamide, has generated a great deal of excitement and stimulated considerable research. However, anandamide and oleamide are merely the best-known and best-understood members of a much larger family of biologically occurring fatty acid amides. In this review, we will outline which fatty acid amides have been isolated from mammalian sources, detail what is known about how these molecules are made and degraded in vivo, and highlight their potential for the development of novel therapeutics.

Endocannabinoids and related compounds: walking back and forth between plant natural products and animal physiology

Cannabis sativa has been known, used, and misused by mankind for centuries, and yet only over the last two decades has research stemming from the chemical constituents specific to this plant, the cannabinoids, started to provide fundamental insights into animal physiology and pathology, resulting in the development of new therapeutics. The discovery of the endocannabinoid system, and its targeting with two new pharmaceutical preparations now on the market in several countries, represent the most recent example of how studies on medicinal plants and on the mechanism of their biological effects can reveal, through a chain of breakthroughs, new systems of endogenous signals and physiological phenomena that can become the source of novel strategies for unmet therapeutic challenges.

Cytochrome c catalyzes the in vitro synthesis of arachidonoyl glycine

Long chain fatty acyl glycines are an emerging class of biologically active molecules that occur naturally and produce a wide array of physiological effects. Their biosynthetic pathway, however, remains unknown. Here we report that cytochrome c catalyzes the synthesis of N-arachidonoyl glycine (NAGly) from arachidonoyl coenzyme A and glycine in the presence of hydrogen peroxide. The identity of the NAGly product was verified by isotope labeling and mass analysis. Other heme-containing proteins, hemoglobin and myoglobin, were considerably less effective in generating arachidonoyl glycine as compared to cytochrome c. The reaction catalyzed by cytochrome c in vitro points to its potential role in the formation of NAGly and other long chain fatty acyl glycines in vivo.

The complications of promiscuity: endocannabinoid action and metabolism

In this review, we present our understanding of the action and metabolism of endocannabinoids and related endogenous molecules. It is clear that the interactions between the multiple endocannabinoid-like molecules (ECLs) are highly complex, both at the level of signal transduction and metabolism. Thus, ECLs are a group of ligands active at 7-transmembrane and nuclear receptors, as well as transmitter-gated and ion channels. ECLs and their metabolites can converge on common endpoints (either metabolic or signalling) through contradictory or reinforcing pathways. We highlight the complexity of the endocannabinoid system, based on the promiscuous nature of ECLs and their metabolites, as well as the synthetic modulators of the endocannabinoid system.

In vitro synthesis of oleoylglycine by cytochrome c points to a novel pathway for the production of lipid signaling molecules

Long chain fatty acyl glycines represent a new class of signaling molecules whose biosynthetic pathway is unknown. Here we report that cytochrome c catalyzes the formation of oleoylglycine from oleoyl-CoA and glycine, in the presence of hydrogen peroxide. The identity of oleoylglycine product was confirmed by isotope labeling and fragmentation mass spectrometry. Synthesis of oleoylglycine by cytochrome c was dependent upon substrate concentration and time. Other heme-containing proteins, myoglobin and hemoglobin, did not catalyze oleoylglycine synthesis. The functional properties of the reaction closely resemble those observed for the ability of cytochrome c to mediate the synthesis of oleamide from oleoyl-CoA and ammonia, in the presence of hydrogen peroxide (Driscoll, W. J., Chaturvedi., S., and Mueller, G. P. (2007) J. Biol. Chem. 282). The ability of cytochrome c to catalyze the formation of oleoylglycine experimentally indicates the potential importance of cytochrome c as a novel mechanism for the generation of long chain fatty acyl glycine messengers in vivo.