Corrigendum: Oral ultramicronized palmitoylethanolamide: plasma and tissue levels and spinal antihyperalgesic effect.

[This corrects the article DOI: 10.3389/fphar.2018.00249.].

The short-chain fatty acid acetate modulates orexin/hypocretin neurons: A novel mechanism in gut-brain axis regulation of energy homeostasis and feeding.

The short-chain fatty acids (SCFAs) acetate, propionate and butyrate, the major products of intestinal microbial fermentation of dietary fibres, are involved in fine-tuning brain functions via the gut-brain axis. However, the effects of SCFAs in the hypothalamic neuronal network regulating several autonomic-brain functions are still unknown. Using NMR spectroscopy, we detected a reduction in brain acetate concentrations in the hypothalamus of obese leptin knockout ob/ob mice compared to lean wild-type littermates. Therefore, we investigated the effect of acetate on orexin/hypocretin neurons (hereafter referred as OX or OX-A neurons), a subset of hypothalamic neurons regulating energy homeostasis, which we have characterized in previous studies to be over-activated by the lack of leptin and enhancement of endocannabinoid tone in the hypothalamus of ob/ob mice. We found that acetate reduces food-intake in concomitance with a reduction of orexin neuronal activity in ob/ob mice. This was demonstrated by evaluating food-intake behaviour and orexin-A/c-FOS immunoreactivity coupled with patch-clamp recordings in Hcrt-eGFP neurons, quantification of prepro-orexin mRNA, and immunolabeling of GPR-43, the main acetate receptor. Our data provide new insights into the mechanisms of the effects of chronic dietary supplementation with acetate, or complex carbohydrates, on energy intake and body weight, which may be partly mediated by inhibition of orexinergic neuron activity.

The human milk endocannabinoidome and neonatal growth in gestational diabetes.

Objective: Endocannabinoids and their N-acyl-ethanolamines (NAEs) and 2monoacyl-glycerols (2-MAGs) congeners are involved in the central and peripheral regulation of energy homeostasis, they are present in human milk and are associated with obesity. Infants exposed in utero to gestational diabetes mellitus (GDM) are more likely to develop obesity. The objective of this cross-sectional study is to compare the profile of eCBome mediators in milk of women with gestational diabetes (GDM+) and without (GDM-) and to assess the association with offspring growth. The hypothesis is that the eCBome of GDM+ human milk is altered and associated with a difference in infant growth. Methods: Circulating eCBome mediators were measured by LC-MS/MS in human milk obtained at 2 months postpartum from GDM+ (n=24) and GDM- (n=29) women. Infant weight and height at 2 months were obtained from the child health record. Z-scores were calculated. Results: Circulating Npalmitoylethanolamine (PEA) was higher in human milk of GDM+ women than in GDM- women (4.9 ± 3.2 vs. 3.3 ± 1.7, p=0.04). Higher levels were also found for several 2monoacyl-glycerols (2-MAGs) (p<0.05). The levels of NAEs (ß=-4.6, p=0.04) and especially non-omega-3 NAEs (B=-5.6, p=0.004) in human milk were negatively correlated with weight-for-age z-score of GDM+ offspring. Conclusion: The profile of eCBome mediators in human milk at 2 months postpartum was different in GDM+ compared to GDM- women and was associated with GDM+ offspring growth at 2 months. Clinical trial registration: ClinicalTrials.gov, identifier (NCT04263675 and NCT02872402).

Altered levels of phospholipases C, diacylglycerols, endocannabinoids, and N-acylethanolamines in patients with hereditary angioedema due to FXII mutation.

BACKGROUND: Hereditary angioedema (HAE) is a rare genetic disorder characterized by local, self-limiting edema due to temporary increase in vascular permeability. HAE with normal C1 esterase inhibitor (C1INH) activity includes the form with mutations in the F12 gene encoding for coagulation factor XII (FXII-HAE) causing an overproduction of bradykinin (BK) leading to angioedema attack. BK binding to B2 receptors (BK2R) leads to an activation of phospholipase C (PLC) and subsequent generation of second messengers: diacylglycerols (DAGs) and possibly the endocannabinoids (eCBs), 2-arachidonoylglycerol (2-AG) and anandamide (AEA), and eCB-related N-acylethanolamines [palmitoylethanolamide (PEA) and oleoylethanolamide (OEA)]. To date, there are no data on the role of these lipid mediators in FXII-HAE. METHODS: Here, we analyzed plasma levels of PLC, DAGs, and eCBs in 40 patients with FXII-HAE and 40 sex- and age-matched healthy individuals. RESULTS: Plasma PLC activity was increased in FXII-HAE patients compared to controls. Concentrations of DAG 18:1-20:4, a lipid second messenger produced by PLC, were higher in FXII-HAE compared to controls, and positively correlated with PLC activity and cleaved high molecular kininogen (cHK). Also the concentrations of the DAG metabolite, 2-AG were altered in FXII-HAE. AEA and OEA were decreased in FXII-HAE patients compared to controls; by contrast, PEA, was increased. The levels of all tested mediators did not differ between symptomatic and asymptomatic patients. Moreover, C1INH-HAE patients had elevated plasma levels of PLC, which correlated with cHK, but the levels of DAGs and eCBs were the same as controls. CONCLUSIONS: BK overproduction and BKR2 activation are linked to alteration of PLCs and their metabolites in patients with FXII-HAE. Our results may pave way to investigations on the functions of these mediators in the pathophysiology of FXII-HAE, and provide new potential biomarkers and therapeutic targets.

Human gut microbiota and their production of endocannabinoid-like mediators are directly affected by a dietary oil.

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFAs) and the gut microbiome affect each other. We investigated the impact of supplementation with Buglossoides arvensis oil (BO), rich in stearidonic acid (SDA), on the human gut microbiome. Employing the Mucosal Simulator of the Human Intestinal Microbial Ecosystem (M-SHIME), we simulated the ileal and ascending colon microbiomes of four donors. Our results reveal two distinct microbiota clusters influenced by BO, exhibiting shared and contrasting shifts. Notably, Bacteroides and Clostridia abundance underwent similar changes in both clusters, accompanied by increased propionate production in the colon. However, in the ileum, cluster 2 displayed a higher metabolic activity in terms of BO-induced propionate levels. Accordingly, a triad of bacterial members involved in propionate production through the succinate pathway, namely Bacteroides, Parabacteroides, and Phascolarctobacterium, was identified particularly in this cluster, which also showed a surge of second-generation probiotics, such as Akkermansia, in the colon. Finally, we describe for the first time the capability of gut bacteria to produce N-acyl-ethanolamines, and particularly the SDA-derived N-stearidonoyl-ethanolamine, following BO supplementation, which also stimulated the production of another bioactive endocannabinoid-like molecule, commendamide, in both cases with variations across individuals. Spearman correlations enabled the identification of bacterial genera potentially involved in endocannabinoid-like molecule production, such as, in agreement with previous reports, Bacteroides in the case of commendamide. This study suggests that the potential health benefits on the human microbiome of certain dietary oils may be amenable to stratified nutrition strategies and extend beyond n-3 PUFAs to include microbiota-derived endocannabinoid-like mediators.

PEA-OXA restores cognitive impairments associated with vitamin D deficiency-dependent alterations of the gut microbiota.

There is a growing evidence suggesting the association of vitamin D deficiency (VDD) and cognitive impairment. In this study we evaluated the possible involvement of gut microbiota in the cognitive impairments mediated by VDD and investigated the effects of pharmacological treatment with the oxazoline derivative of the aliamide palmitoylethanolamide, 2-Pentadecyl-2-oxazoline (PEA-OXA). Mice were submitted to behavioural, biochemical and electrophysiological analysis to assess whether their vitamin D status affected cognitive performance together with gut microbiota composition. In VDD mice we found cognitive malfunctioning associated with reduced neuroplasticity, indicated by impaired long term potentiation, and neuroinflammation at the hippocampal level. Importantly, PEA-OXA counteracted the cognitive impairments and modified the biochemical and functional changes induced by VDD. Additionally, PEA-OXA treatment enhanced gut microbiota diversity, which tended to be decreased by VDD only in female mice, elevated the relative abundance of lactic and butyric acid-producing families, i.e. Aerococcaceae and Butyricicoccaceae, and reversed the VDD-induced decrease of butyrate-producing beneficial genera, such as Blautia in female mice, and Roseburia in male mice. These data provide novel insights for a better understanding of the cognitive decline induced by VDD and related gut dysbiosis and its potential therapeutic treatment.

Investigating the alterations of endocannabinoidome signaling in the human small intestine in the context of obesity and type 2 diabetes.

Background: Human studies have linked obesity-related diseases, such as type-2 diabetes (T2D), to the modulation of endocannabinoid signaling. Cannabinoid CB1 and CB2 receptor activation by the endocannabinoids (eCBs) 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA), both derived from arachidonic acid, play a role in homeostatic regulation. Other long chain fatty acid-derived endocannabinoid-like molecules have extended the metabolic role of this signaling system through other receptors. In this study, we aimed to assess in depth the interactions between the circulating and intestinal tone of this extended eCB system, or endocannabinoidome (eCBome), and their involvement in the pathogenesis of diabetes. Methods: Plasma and ileum samples were collected from subjects with obesity and harboring diverse degrees of insulin resistance or T2D, who underwent bariatric surgery. The levels of eCBome mediators and their congeners were then assessed by liquid chromatography coupled to tandem mass spectrometry, while gene expression was screened with qPCR arrays. Findings: Intestinal and circulating levels of eCBome mediators were higher in subjects with T2D. We found an inverse correlation between the intestinal and circulating levels of monoacylglycerols (MAGs). Additionally, we identified genes known to be implicated in both lipid metabolism and intestinal function that are altered by the context of obesity and glucose homeostasis. Interpretation: Although the impact of glucose metabolism on the eCBome remains poorly understood in subjects with advanced obesity state, our results suggest a strong causative link between altered glucose homeostasis and eCBome signaling in the intestine and the circulation.

Cannabidiol reduces intraventricular hemorrhage brain damage, preserving myelination and preventing blood brain barrier dysfunction in immature rats.

Intraventricular hemorrhage (IVH) is an important cause of long-term disability in extremely preterm infants, with no current treatment. This study assessed the potential neuroprotective effects of cannabidiol (CBD) in an IVH model using immature rats. IVH was induced in 1-day-old (P1) Wistar rats by left periventricular injection of Clostridial collagenase. Some rats received CBD prenatally (10 â€‹mg/kg i.p. to the dam) and then 5 â€‹mg/kg i.p. 6, 30 and 54 â€‹h after IVH (IVH+CBD, n â€‹= â€‹30). Other IVH rats received vehicle (IVH+VEH, n â€‹= â€‹34) and vehicle-treated non-IVH rats served as controls (SHM, n â€‹= â€‹29). Rats were humanely killed at P6, P14 or P45. Brain damage (motor and memory performance, area of damage, Lactate/N-acetylaspartate ratio), white matter injury (ipsilateral hemisphere and corpus callosum volume, oligodendroglial cell density and myelin basic protein signal), blood-brain barrier (BBB) integrity (Mfsd2a, occludin and MMP9 expression, gadolinium leakage), inflammation (TLR4, NFκB and TNFα expression, infiltration of pro-inflammatory cells), excitotoxicity (Glutamate/N-acetylspartate ratio) and oxidative stress (protein nitrosylation) were then evaluated. CBD prevented the long-lasting motor and cognitive consequences of IVH, reduced brain damage in the short- and long-term, protected oligodendroglial cells preserving adequate myelination and maintained BBB integrity. The protective effects of CBD were associated with the modulation of inflammation, excitotoxicity and oxidative stress. In conclusion, in immature rats, CBD reduced IVH-induced brain damage and its short- and long-term consequences, showing robust and pleiotropic neuroprotective effects. CBD is a potential candidate to ameliorate IVH-induced immature brain damage.

Pharmacological evidence that the inhibitory effects of prostaglandin E2 are mediated by the EP2 and EP4 receptors in human neutrophils.

Prostaglandin E2 (PGE2) is a recognized inhibitor of granulocyte functions. However, most of the data supporting this was obtained when available pharmacological tools mainly targeted the EP2 receptor. Herein, we revisited the inhibitory effect of PGE2 on reactive oxygen species production, leukotriene biosynthesis, and migration in human neutrophils. Our data confirm the inhibitory effect of PGE2 on these functions and unravel that the effect of PGE2 on human neutrophils is obtained by the combined action of EP2 and EP4 agonism. Accordingly, we also demonstrate that the inhibitory effect of PGE2 is fully prevented only by the combination of EP2 and EP4 receptor antagonists, underscoring the importance of targeting both receptors in the effect of PGE2. Conversely, we also show that the inhibition of ROS production by human eosinophils only involves the EP4 receptor, despite the fact that they also express the EP2 receptor.

Mathematical modeling of fluid dynamics in in vitro gut fermentation systems: A new tool to improve the interpretation of microbial metabolism.

In vitro systems are widely employed to assess the impact of dietary compounds on the gut microbiota and their conversion into beneficial bacterial metabolites. However, the complex fluid dynamics and multi-segmented nature of these systems can complicate the comprehensive analysis of dietary compound fate, potentially confounding physical dilution or washout with microbial catabolism. In this study, we developed fluid dynamics models based on sets of ordinary differential equations to simulate the behavior of an inert compound within two commonly used in vitro systems: the continuous two-stage PolyFermS system and the semi-continuous multi-segmented SHIME® system as well as into various declinations of those systems. The models were validated by investigating the fate of blue dextran, demonstrating excellent agreement between experimental and modeling data (with r2 values ranging from 0.996 to 0.86 for different approaches). As a proof of concept for the utility of fluid dynamics models in in vitro system, we applied generated models to interpret metabolomic data of procyanidin A2 (ProA2) generated from the addition of proanthocyanidin (PAC)-rich cranberry extract to both the PolyFermS and SHIME® systems. The results suggested ProA2 degradation by the gut microbiota when compared to the modeling of an inert compound. Models of fluid dynamics developed in this study provide a foundation for comprehensive analysis of gut metabolic data in commonly utilized in vitro PolyFermS and SHIME® bioreactor systems and can enable a more accurate understanding of the contribution of bacterial metabolism to the variability in the concentration of target metabolites.

Development of Potent and Selective Monoacylglycerol Lipase Inhibitors. SARs, Structural Analysis, and Biological Characterization.

New potent, selective monoacylglycerol lipase (MAGL) inhibitors based on the azetidin-2-one scaffold ((±)-5a-v, (±)-6a-j, and (±)-7a-d) were developed as irreversible ligands, as demonstrated by enzymatic and crystallographic studies for (±)-5d, (±)-5l, and (±)-5r. X-ray analyses combined with extensive computational studies allowed us to clarify the binding mode of the compounds. 5v was identified as selective for MAGL when compared with other serine hydrolases. Solubility, in vitro metabolic stability, cytotoxicity, and absence of mutagenicity were determined for selected analogues. The most promising compounds ((±)-5c, (±)-5d, and (±)-5v) were used for in vivo studies in mice, showing a decrease in MAGL activity and increased 2-arachidonoyl-sn-glycerol levels in forebrain tissue. In particular, 5v is characterized by a high eudysmic ratio and (3R,4S)-5v is one of the most potent irreversible inhibitors of h/mMAGL identified thus far. These results suggest that the new MAGL inhibitors have therapeutic potential for different central and peripheral pathologies.

Early endocannabinoid-mediated depolarization-induced suppression of excitation delays the appearance of the epileptic phenotype in synapsin II knockout mice.

The mechanism underlying the transition from the pre-symptomatic to the symptomatic state is a crucial aspect of epileptogenesis. SYN2 is a member of a multigene family of synaptic vesicle phosphoproteins playing a fundamental role in controlling neurotransmitter release. Human SYN2 gene mutations are associated with epilepsy and autism spectrum disorder. Mice knocked out for synapsin II (SynII KO) are prone to epileptic seizures that appear after 2 months of age. However, the involvement of the endocannabinoid system, known to regulate seizure development and propagation, in the modulation of the excitatory/inhibitory balance in the epileptic hippocampal network of SynII KO mice has not been explored. In this study, we investigated the impact of endocannabinoids on glutamatergic and GABAergic synapses at hippocampal dentate gyrus granule cells in young pre-symptomatic (1-2 months old) and adult symptomatic (5-8 months old) SynII KO mice. We observed an increase in endocannabinoid-mediated depolarization-induced suppression of excitation in young SynII KO mice, compared to age-matched wild-type controls. In contrast, the endocannabinoid-mediated depolarization-induced suppression of inhibition remained unchanged in SynII KO mice at both ages. This selective alteration of excitatory synaptic transmission was accompanied by changes in hippocampal endocannabinoid levels and cannabinoid receptor type 1 distribution among glutamatergic and GABAergic synaptic terminals contacting the granule cells of the dentate gyrus. Finally, inhibition of type-1 cannabinoid receptors in young pre-symptomatic SynII KO mice induced seizures during a tail suspension test. Our results suggest that endocannabinoids contribute to maintaining network stability in a genetic mouse model of human epilepsy.

Effect of a Probiotic Beverage Enriched with Cricket Proteins on the Gut Microbiota: Composition of Gut and Correlation with Nutritional Parameters.

The health and balance of the gut microbiota are known to be linked to diet composition and source, with fermented products and dietary proteins potentially providing an exceptional advantage for the gut. The purpose of this study was to evaluate the effect of protein hydrolysis, using a probiotic beverage enriched with either cricket protein (CP) or cricket protein hydrolysates (CP.Hs), on the composition of the gut microbiota of rats. Taxonomic characterization of the gut microbiota in fecal samples was carried out after a 14-day nutritional study to identify modifications induced by a CP- and CP.H-enriched fermented probiotic product. The results showed no significant differences (p > 0.05) in the diversity and richness of the gut microbiota among the groups fed with casein (positive control), CP-enriched, and fermented CP.H-enriched probiotic beverages; however, the overall composition of the microbiota was altered, with significant modifications in the relative abundance of several bacterial families and genera. In addition, fermented CP.H-enriched probiotic beverages could be related to the decrease in the number of potential pathogens such as Enterococcaceae. The association of gut microbiota with the nutritional parameters was determined and the results showed that digestibility and the protein efficiency ratio (PER) were highly associated with the abundance of several taxa.

Association between the FAAH C385A variant (rs324420) and obesity-related traits: a systematic review.

BACKGROUND: Overweight and obesity are the consequence of a sustained positive energy balance. Twin studies show high heritability rates pointing to genetics as one of the principal risk factors. By 2022, genomic studies led to the identification of almost 300 obesity-associated variants that could help to fill the gap of the high heritability rates. The endocannabinoid system is a critical regulator of metabolism for its effects on the central nervous system and peripheral tissues. Fatty acid amide hydrolase (FAAH) is a key enzyme in the inactivation of one of the two endocannabinoids, anandamide, and of its congeners. The rs324420 variant within the FAAH gene is a nucleotide missense change at position 385 from cytosine to adenine, resulting in a non-synonymous amino acid substitution from proline to threonine in the FAAH enzyme. This change increases sensitivity to proteolytic degradation, leading to reduced FAAH levels and increased levels of anandamide, associated with obesity-related traits. However, association studies of this variant with metabolic parameters have found conflicting results. This work aims to perform a systematic review of the existing literature on the association of the rs324420 variant in the FAAH gene with obesity and its related traits. METHODS: A literature search was conducted in PubMed, Web of Science, and Scopus. A total of 645 eligible studies were identified for the review. RESULTS/CONCLUSIONS: After the identification, duplicate elimination, title and abstract screening, and full-text evaluation, 28 studies were included, involving 28 183 individuals. We show some evidence of associations between the presence of the variant allele and higher body mass index, waist circumference, fat mass, and waist-to-hip ratio levels and alterations in glucose and lipid homeostasis. However, this evidence should be taken with caution, as many included studies did not report a significant difference between genotypes. These discordant results could be explained mainly by the pleiotropy of the endocannabinoid system, the increase of other anandamide-like mediators metabolized by FAAH, and the influence of gene-environment interactions. More research is necessary to study the endocannabinoidomic profiles and their association with metabolic diseases.

Olive oil-derived endocannabinoid-like mediators inhibit palatable food-induced reward and obesity.

N-oleoylglycine (OlGly), a lipid derived from the basic component of olive oil, oleic acid, and N-oleoylalanine (OlAla) are endocannabinoid-like mediators. We report that OlGly and OlAla, by activating the peroxisome proliferator-activated receptor alpha (PPARα), reduce the rewarding properties of a highly palatable food, dopamine neuron firing in the ventral tegmental area, and the obesogenic effect of a high-fat diet rich in lard (HFD-L). An isocaloric olive oil HFD (HFD-O) reduced body weight gain compared to the HFD-L, in a manner reversed by PPARα antagonism, and enhanced brain and intestinal OlGly levels and gut microbial diversity. OlGly or OlAla treatment of HFD-L mice resulted in gut microbiota taxonomic changes partly similar to those induced by HFD-O. We suggest that OlGly and OlAla control body weight by counteracting highly palatable food overconsumption, and possibly rebalancing the gut microbiota, and provide a potential new mechanism of action for the obeso-preventive effects of olive oil-rich diets.

Dietary food patterns as determinants of the gut microbiome-endocannabinoidome axis in humans.

The gut microbiota and the endocannabinoidome (eCBome) play important roles in regulating energy homeostasis, and both are closely linked to dietary habits. However, the complex and compositional nature of these variables has limited our understanding of their interrelationship. This study aims to decipher the interrelation between dietary intake and the gut microbiome-eCBome axis using two different approaches for measuring dietary intake: one based on whole food and the other on macronutrient intakes. We reveal that food patterns, rather than macronutrient intakes, were associated with the gut microbiome-eCBome axis in a sample of healthy men and women (n = 195). N-acyl-ethanolamines (NAEs) and gut microbial families were correlated with intakes of vegetables, refined grains, olive oil and meats independently of adiposity and energy intakes. Specifically, higher intakes in vegetables and olive oil were associated with increased relative abundance of Clostridiaceae, Veillonellaceae and Peptostreptococaceae, decreased relative abundance of Acidominococaceae, higher circulating levels of NAEs, and higher HDL and LDL cholesterol levels. Our findings highlight the relative importance of food patterns in determining the gut microbiome-eCBome axis. They emphasize the importance of recognizing the contribution of dietary habits in these systems to develop personalized dietary interventions for preventing and treating metabolic disorders through this axis.

New role for the anandamide metabolite prostaglandin F2α ethanolamide: Rolling preadipocyte proliferation.

White adipose tissue regulation is key to metabolic health, yet still perplexing. The chief endocannabinoid anandamide metabolite, prostaglandin F2α ethanolamide (PGF2αEA), inhibits adipogenesis, that is, the formation of mature adipocytes. We observed that adipocyte progenitor cells-preadipocytes-following treatment with PGF2αEA yielded larger pellet sizes. Thus, we hypothesized that PGF2αEA might augment preadipocyte proliferation. Cell viability MTT and crystal violet assays, cell counting, and 5-bromo-2'-deoxyuridine incorporation in cell proliferation ELISA analyses confirmed our prediction. Additionally, we discovered that PGF2αEA promotes cell cycle progression through suppression of the expression of cell cycle inhibitors, p21 and p27, as shown by flow cytometry and qPCR. Enticingly, concentrations of this compound that showed no visible effect on cell proliferation or basal transcriptional activity of peroxisome proliferator-activated receptor gamma could, in contrast, reverse the anti-proliferative and peroxisome proliferator-activated receptor gamma-transcription activating effects of rosiglitazone (Rosi). MTT and luciferase reporter examinations supported this finding. The PGF2αEA pharmaceutical analog, bimatoprost, was also investigated and showed very similar effects. Importantly, we suggest the implication of the mitogen-activated protein kinase pathway in these effects, as they were blocked by the selective mitogen-activated protein kinase kinase inhibitor, PD98059. We propose that PGF2αEA is a pivotal regulator of white adipose tissue plasticity, acting as a regulator of the preadipocyte pool in adipose tissue.

Dysfunctional endocannabinoid CB1 receptor expression and signaling contribute to skeletal muscle cell toxicity induced by simvastatin.

Statins are the most prescribed lipid-lowering agents worldwide. Their use is generally safe, although muscular toxicity occurs in about 1 in 10.000 patients. In this study, we explored the role of the endocannabinoid system (ECS) during muscle toxicity induced by simvastatin. In murine C2C12 myoblasts exposed to simvastatin, levels of the endocannabinoids AEA and 2-AG as well the expression of specific miRNAs (in particular miR-152) targeting the endocannabinoid CB1 gene were increased in a time-dependent manner. Rimonabant, a selective CB1 antagonist, exacerbated simvastatin-induced toxicity in myoblasts, while only a weak opposite effect was observed with ACEA and GAT211, selective orthosteric and allosteric agonists of CB1 receptor, respectively. In antagomiR152-transfected myoblasts, simvastatin toxicity was in part prevented together with the functional rescue of CB1. Further analyses revealed that simvastatin in C2C12 cells also suppresses PKC and ERK signaling pathways, which are instead activated downstream of CB1 receptor stimulation, thus adding more insight into the mechanism causing CB1 functional inactivation. Importantly, simvastatin induced similar alterations in skeletal muscles of C57BL/6 J mice and primary human myoblasts. In sum, we identified the dysregulated expression of the endocannabinoid CB1 receptor as well as the impairment of its downstream signaling pathways as a novel pathological mechanism involved in statin-induced myopathy.

Gene-based microbiome representation enhances host phenotype classification.

With the concomitant advances in both the microbiome and machine learning fields, the gut microbiome has become of great interest for the potential discovery of biomarkers to be used in the classification of the host health status. Shotgun metagenomics data derived from the human microbiome is composed of a high-dimensional set of microbial features. The use of such complex data for the modeling of host-microbiome interactions remains a challenge as retaining de novo content yields a highly granular set of microbial features. In this study, we compared the prediction performances of machine learning approaches according to different types of data representations derived from shotgun metagenomics. These representations include commonly used taxonomic and functional profiles and the more granular gene cluster approach. For the five case-control datasets used in this study (Type 2 diabetes, obesity, liver cirrhosis, colorectal cancer, and inflammatory bowel disease), gene-based approaches, whether used alone or in combination with reference-based data types, allowed improved or similar classification performances as the taxonomic and functional profiles. In addition, we show that using subsets of gene families from specific functional categories of genes highlight the importance of these functions on the host phenotype. This study demonstrates that both reference-free microbiome representations and curated metagenomic annotations can provide relevant representations for machine learning based on metagenomic data. IMPORTANCE Data representation is an essential part of machine learning performance when using metagenomic data. In this work, we show that different microbiome representations provide varied host phenotype classification performance depending on the dataset. In classification tasks, untargeted microbiome gene content can provide similar or improved classification compared to taxonomical profiling. Feature selection based on biological function also improves classification performance for some pathologies. Function-based feature selection combined with interpretable machine learning algorithms can generate new hypotheses that can potentially be assayed mechanistically. This work thus proposes new approaches to represent microbiome data for machine learning that can potentiate the findings associated with metagenomic data.

FAAH Pro129Thr Variant Is Associated with Increased Cholesterol Levels in Normal-Weight Metabolically Unhealthy Subjects.

Introduction: The endocannabinoid system (ECS) plays an integral role in maintaining metabolic homeostasis, where an hyperactivation has been related with serum lipid alterations. The biological effects of ECS are limited by the activation of the endocannabinoid-degrading enzyme fatty acid amide hydrolase (FAAH) and by polyunsaturated fatty acid (PUFA) intake as precursors. The FAAH Pro129Thr variant has been associated with obesity in some populations. However, the association with metabolic phenotypes in the Mexican population has not been studied. This study aimed to analyze the association of the FAAH Pro129Thr variant with serum lipids and diet in Mexican adults with different metabolic phenotypes. Methods: This is a cross-sectional study with 306 subjects between 18 and 65 years of age. They were classified with normal weight (NW) or excess weight (EW) according to their body mass index (BMI). The EW group included individuals with overweight or obesity (BMI 25-39.9 kg/m2). The individuals were classified into two metabolic phenotypes, metabolically healthy and metabolically unhealthy (MUH), using the homeostatic model assessment of insulin resistance and the National Cholesterol Education Program-adenosine triphosphate III cutoff points for blood pressure, triglycerides, high-density lipoprotein cholesterol, and fasting glucose. Subjects with ≥2 of 5 altered parameters were classified as MUH. The FAAH Pro129Thr variant was determined by allelic discrimination with TaqMan® probes. Results: The total cholesterol and very low-density lipoprotein cholesterol levels were associated with the FAAH Pro129Thr variant in NW-MUH subjects. Moreover, a lower PUFA intake was found in EW-MUH subjects with the FAAH variant. Conclusions: FAAH Pro129Thr variant has an important role in lipid metabolism, especially in NW-MUH subjects. By contrast, a low dietary intake of endocannabinoid PUFA precursors may partly counteract the development of the altered lipid profile associated with overweight/obesity.