Radiometric Assay of NAPE-PLD Activity.

N-Acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a prominent enzyme involved in the biosynthesis of fatty acid amides, a family of bioactive lipids including anandamide as the prototypical member. Here, we describe a NAPE-PLD assay based on radioactive substrates and product separation by thin layer chromatography (TLC).

Cannabinoid CB2 receptor ligand profiling reveals biased signalling and off-target activity.

The cannabinoid CB2 receptor (CB2R) represents a promising therapeutic target for various forms of tissue injury and inflammatory diseases. Although numerous compounds have been developed and widely used to target CB2R, their selectivity, molecular mode of action and pharmacokinetic properties have been poorly characterized. Here we report the most extensive characterization of the molecular pharmacology of the most widely used CB2R ligands to date. In a collaborative effort between multiple academic and industry laboratories, we identify marked differences in the ability of certain agonists to activate distinct signalling pathways and to cause off-target effects. We reach a consensus that HU910, HU308 and JWH133 are the recommended selective CB2R agonists to study the role of CB2R in biological and disease processes. We believe that our unique approach would be highly suitable for the characterization of other therapeutic targets in drug discovery research.

Assay of NAPE-PLD Activity.

N-acyl-phosphatidylethanolamine (NAPE)-hydrolyzing phospholipase D (NAPE-PLD) is a prominent enzyme involved in the biosynthesis of fatty acid amides (FAAs), a family of bioactive lipids including anandamide (AEA) as the prototypical member. Here, we describe a NAPE-PLD assay based on radioactive substrates and product separation by thin-layer chromatography (TLC).

Lipid Discovery by Combinatorial Screening and Untargeted LC-MS/MS.

We present a method for the systematic identification of picogram quantities of new lipids in total extracts of tissues and fluids. It relies on the modularity of lipid structures and applies all-ions fragmentation LC-MS/MS and Arcadiate software to recognize individual modules originating from the same lipid precursor of known or assumed structure. In this way it alleviates the need to recognize and fragment very low abundant precursors of novel molecules in complex lipid extracts. In a single analysis of rat kidney extract the method identified 58 known and discovered 74 novel endogenous endocannabinoids and endocannabinoid-related molecules, including a novel class of N-acylaspartates that inhibit Hedgehog signaling while having no impact on endocannabinoid receptors.

A functional interplay between 5-lipoxygenase and µ-calpain affects survival and cytokine profile of human Jurkat T lymphocyte exposed to simulated microgravity.

A growing body of evidence strongly indicates that both simulated and authentic weightlessness exert a broad range of effects on mammalian tissues and cells, including impairment of immune cell function and increased apoptotic death. We previously reported that microgravity-dependent activation of 5-lipoxygenase (5-LOX) might play a central role in the initiation of apoptosis in human T lymphocytes, suggesting that the upregulation of this enzyme might be (at least in part) responsible for immunodepression observed in astronauts during space flights. Herein, we supplement novel information about the molecular mechanisms underlying microgravity-triggered apoptotic cell death and immune system deregulation, demonstrating that under simulated microgravity human Jurkat T cells increase the content of cytosolic DNA fragments and cytochrome c (typical hallmarks of apoptosis) and have an upregulated expression and activity of µ-calpain. These events were paralleled by the unbalance of interleukin- (IL-) 2 and interferon- (INF-) γ, anti- and proapoptotic cytokines, respectively, that seemed to be dependent on the functional interplay between 5-LOX and µ-calpain. Indeed, we report unprecedented evidence that 5-LOX inhibition reduced apoptotic death, restored the initial IL-2/INF-γ ratio, and more importantly reverted µ-calpain activation induced by simulated microgravity.

Endocannabinoids produced upon action potential firing evoke a Cl(-) current via type-2 cannabinoid receptors in the medial prefrontal cortex.

The functional presence of type-2 cannabinoid receptors (CB2Rs) in layer II/III pyramidal neurons of the rat medial prefrontal cortex (mPFC) was recently demonstrated. In the present study, we show that the application of the endocannabinoids (eCBs) 2-arachidonoylglycerol (2-AG) and methanandamide [a stable analog of the eCB anandamide (AEA)] can activate CB2Rs of mPFC layer II/III pyramidal neurons, which subsequently induces a Cl(-) current. In addition, we show that action potential (AP) firing evoked by 20-Hz current injections results in an eCB-mediated opening of Cl(-) channels via CB2R activation. This AP-evoked synthesis of eCBs is dependent on the Ca(2+) influx through N-type voltage-gated calcium channels. Our results indicate that 2-AG is the main eCB involved in this process. Finally, we demonstrate that under physiologically relevant intracellular Cl(-) conditions, 20-Hz AP firing leads to a CB2R-dependent reduction in neuronal excitability. Altogether, our data indicate that eCBs released upon action potential firing can modulate, through CB2R activation, neuronal activity in the mPFC. We discuss how this may be a mechanism to prevent excessive neuronal firing.

In vitro and in vivo models of Huntington's disease show alterations in the endocannabinoid system.

In this study, we analyzed the components of the endocannabinoid system (ECS) in R6/2 mice, a widely used model of Huntington's disease (HD). We measured the endogenous content of N-arachidonoylethanolamine and 2-arachidonoylglycerol and the activity of their biosynthetic enzymes (N-acyl-phosphatidylethanolamine-hydrolyzing phospholipase D and diacylglycerol lipase, respectively) and hydrolytic enzymes [fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase, respectively] and of their target receptors (type 1 cannabinoid receptor, type 2 cannabinoid receptor, and transient receptor potential vanilloid-1) in the brains of wild-type and R6/2 mice of different ages, as well as in the striatum and cortex of 12-week-old animals. In addition, we measured FAAH activity in lymphocytes of R6/2 mice. In the whole brains of 12-week-old R6/2 mice, we found reductions in N-acyl-phosphatidylethanolamine-hydrolyzing phospholipase D activity, diacylglycerol lipase activity and cannabinoid receptor binding, mostly associated with changes in the striatum but not in the cortex, as well as an increase in 2-arachidonoylglycerol content as compared with wild-type littermates, without any other change in ECS elements. Then, our analysis was extended to HD43 cells, an inducible cellular model of HD derived from rat ST14A cells. In both induced and noninduced conditions, we demonstrated a fully functional ECS. Overall, our data suggest that the ECS is differently affected in mouse and human HD, and that HD43 cells are suitable for high-throughput screening of FAAH-oriented drugs affecting HD progression.

Association between a genetic variant of type-1 cannabinoid receptor and inflammatory neurodegeneration in multiple sclerosis.

Genetic ablation of type-1 cannabinoid receptors (CB1Rs) exacerbates the neurodegenerative damage of experimental autoimmune encephalomyelitis, the rodent model of multiple sclerosis (MS). To address the role on CB1Rs in the pathophysiology of human MS, we first investigated the impact of AAT trinucleotide short tandem repeat polymorphism of CNR1 gene on CB1R cell expression, and secondly on the inflammatory neurodegeneration process responsible for irreversible disability in MS patients. We found that MS patients with long AAT repeats within the CNR1 gene (≥12 in both alleles) had more pronounced neuronal degeneration in response to inflammatory white matter damage both in the optic nerve and in the cortex. Optical Coherence Tomography (OCT), in fact, showed more severe alterations of the retinal nerve fiber layer (RNFL) thickness and of the macular volume (MV) after an episode of optic neuritis in MS patients carrying the long AAT genotype of CNR1. MS patients with long AAT repeats also had magnetic resonance imaging (MRI) evidence of increased gray matter damage in response to inflammatory lesions of the white matter, especially in areas with a major role in cognition. In parallel, visual abilities evaluated at the low contrast acuity test, and cognitive performances were negatively influenced by the long AAT CNR1 genotype in our sample of MS patients. Our results demonstrate the biological relevance of the (AAT)n CNR1 repeats in the inflammatory neurodegenerative damage of MS.

5-Lipoxygenase-dependent apoptosis of human lymphocytes in the International Space Station: data from the ROALD experiment.

The functional adaptation of the immune system to the surrounding environment is also a fundamental issue in space. It has been suggested that a decreased number of lymphocytes might be a cause of immunosuppression, possibly due to the induction of apoptosis. Early activation of 5-lipoxygenase (5-LOX) might play a central role in the initiation of the apoptotic program. The goal of the role of apoptosis in lymphocyte depression (ROALD) experiment, flown on the International Space Station as part of the BIO-4 mission of the European Space Agency, was to ascertain the induction of apoptosis in human lymphocytes under authentic microgravity, and to elucidate the possible involvement of 5-LOX. Our results demonstrate that exposure of human lymphocytes to microgravity for 48 h onboard the ISS remarkably increased apoptotic hallmarks such as DNA fragmentation (∼3-fold compared to ground-based controls) and cleaved-poly (ADP-ribose) polymerase (PARP) protein expression (∼3-fold), as well as mRNA levels of apoptosis-related markers such as p53 (∼3-fold) and calpain (∼4-fold); these changes were paralleled by an early increase of 5-LOX activity (∼2-fold). Our findings provide a molecular background for the immune dysfunction observed in astronauts during space missions, and reveal potential new markers to monitor health status of ISS crew members.

The MP65 gene is required for cell wall integrity, adherence to epithelial cells and biofilm formation in Candida albicans.

BACKGROUND: The MP65 gene of Candida albicans (orf19.1779) encodes a putative ß-glucanase mannoprotein of 65 kDa, which plays a main role in a host-fungus relationship, morphogenesis and pathogenicity. In this study, we performed an extensive analysis of a mp65Δ mutant to assess the role of this protein in cell wall integrity, adherence to epithelial cells and biofilm formation. RESULTS: The mp65Δ mutant showed a high sensitivity to a range of cell wall-perturbing and degrading agents, especially Congo red, which induced morphological changes such as swelling, clumping and formation of hyphae. The mp65Δ mutant showed an activation of two MAPKs (Mkc1p and Cek1p), a high level of expression of two stress-related genes (DDR48 and SOD5), and a modulated expression of ß-glucan epitopes, but no gross changes in cell wall polysaccharide composition. Interestingly, the mp65Δ mutant displayed a marked reduction in adhesion to BEC and Caco-2 cells and severe defects in biofilm formation when compared to the wild type. All of the mentioned properties were totally or partially recovered in a revertant strain, demonstrating the specificity of gene deletion. CONCLUSIONS: We demonstrate that the MP65 gene of Candida albicans plays a significant role in maintaining cell wall integrity, as well as in adherence to epithelia and biofilm formation, which are major virulence attributes of this fungus.