Lipolysis pathways modulate lipid mediator release and endocannabinoid system signaling in dairy cows' adipocytes.

BACKGROUND: As cows transition from pregnancy to lactation, free fatty acids (FFA) are mobilized from adipose tissues (AT) through lipolysis to counter energy deficits. In clinically healthy cows, lipolysis intensity is reduced throughout lactation; however, if FFA release exceeds tissue demands or the liver's metabolic capacity, lipid byproducts accumulate, increasing cows' risk of metabolic and infectious disease. Endocannabinoids (eCBs) and their congeners, N-acylethanolamines (NAEs), are lipid-based compounds that modulate metabolism and inflammation. Their synthesis and release depend upon the availability of FFA precursors and the abundance of synthesizing and degrading enzymes and transporters. Therefore, we hypothesized that eCB production and transcription of endocannabinoid system components are modulated by lipolysis pathways in adipocytes. To test this hypothesis, we stimulated canonical (isoproterenol, 1 µmol/L; ISO) and inflammatory (lipopolysaccharide, 1 µg/mL; LPS) lipolysis pathways in adipocytes isolated from the AT of 5 Holstein dairy cows. Following, we assessed lipolysis intensity, adipocytes' release of eCBs, and transcription of endocannabinoid system components. RESULTS: We found that ISO and LPS stimulated lipolysis at comparable intensities. Exposure to either treatment tended to elevate the release of eCBs and NAEs by cultured adipocytes; however, specific eCBs and NAEs and the transcriptional profiles differed by treatment. On one hand, ISO enhanced adipocytes' release of 2-arachidonoylglycerol (2-AG) but reduced NAE production. Notably, ISO enhanced the cells' expression of enzymes associated with 2-AG biosynthesis (INPP5F, GDPD5, GPAT4), transport (CD36), and adipogenesis (PPARG). Conversely, LPS enhanced adipocytes' synthesis and release of N-arachidonoylethanolamide (AEA). This change coincided with enhanced transcription of the NAE-biosynthesizing enzyme, PTPN22, and adipocytes' transcription of genes related to eCB degradation (PTGS2, MGLL, CYP27B1). Furthermore, LPS enhanced adipocytes' transcription of eCB and NAE transporters (HSPA1A, SCP2) and the expression of the anti-adipogenic ion channel, TRPV3. CONCLUSIONS: Our data provide evidence for distinct modulatory roles of canonical and inflammatory lipolysis pathways over eCB release and transcriptional regulation of biosynthesis, degradation, transport, and ECS signaling in cows' adipocytes. Based on our findings, we conclude that, within adipocytes, eCB production and ECS component expression are, at least in part, mediated by lipolysis in a pathway-dependent manner. These findings contribute to a deeper understanding of the molecular mechanisms underlying metabolic regulation in dairy cows' AT, with potential implications for prevention and treatment of inflammatory and metabolic disorders.

Cutaneous Wound Healing and the Effects of Cannabidiol.

Cutaneous wounds, both acute and chronic, begin with loss of the integrity, and thus barrier function, of the skin. Surgery and trauma produce acute wounds. There are 22 million surgical procedures per year in the United States alone, based on data from the American College of Surgeons, resulting in a prevalence of 6.67%. Acute traumatic wounds requiring repair total 8 million per year, 2.42% or 24.2 per 1000. The cost of wound care is increasing; it approached USD 100 billion for just Medicare in 2018. This burden for wound care will continue to rise with population aging, the increase in metabolic syndrome, and more elective surgeries. To heal a wound, an orchestrated, evolutionarily conserved, and complex series of events involving cellular and molecular agents at the local and systemic levels are necessary. The principal factors of this important function include elements from the neurological, cardiovascular, immune, nutritional, and endocrine systems. The objectives of this review are to provide clinicians engaged in wound care and basic science researchers interested in wound healing with an updated synopsis from recent publications. We also present data from our primary investigations, testing the hypothesis that cannabidiol can alter cutaneous wound healing and documenting their effects in wild type (C57/BL6) and db/db mice (Type 2 Diabetes Mellitus, T2DM). The focus is on the potential roles of the endocannabinoid system, cannabidiol, and the important immune-regulatory wound cytokine IL-33, a member of the IL-1 family, and connective tissue growth factor, CTGF, due to their roles in both normal and abnormal wound healing. We found an initial delay in the rate of wound closure in B6 mice with CBD, but this difference disappeared with time. CBD decreased IL-33 + cells in B6 by 70% while nearly increasing CTGF + cells in db/db mice by two folds from 18.6% to 38.8% (p < 0.05) using a dorsal wound model. We review the current literature on normal and abnormal wound healing, and document effects of CBD in B6 and db/db dorsal cutaneous wounds. CBD may have some beneficial effects in diabetic wounds. We applied 6-mm circular punch to create standard size full-thickness dorsal wounds in B6 and db/db mice. The experimental group received CBD while the control group got only vehicle. The outcome measures were rate of wound closure, wound cells expressing IL-33 and CTGF, and ILC profiles. In B6, the initial rate of wound closure was slower but there was no delay in the time to final closure, and cells expressing IL-33 was significantly reduced. CTGF + cells were higher in db/bd wounds treated with CBD. These data support the potential use of CBD to improve diabetic cutaneous wound healing.

The Effect of Phytocannabinoids and Endocannabinoids on Nrf2 Activity in the Central Nervous System and Periphery.

The relationship between nuclear factor erythroid 2-related factor 2 (Nrf2) and phytocannabinoids/endocannabinoids (pCBs/eCBs) has been investigated in a variety of models of peripheral illnesses, with little clarification on their interaction within the central nervous system (CNS). In this context, evidence suggests that the Nrf2-pCBs/eCBS interaction is relevant in modulating peroxidation processes and the antioxidant system. Nrf2, one of the regulators of cellular redox homeostasis, appears to have a protective role toward damaging insults to neurons and glia by enhancing those genes involved in the regulation of homeostatic processes. Specifically in microglia and macroglia cells, Nrf2 can be activated, and its signaling pathway modulated, by both pCBs and eCBs. However, the precise effects of pCBs and eCBs on the Nrf2 signaling pathway are not completely elucidated yet, making their potential clinical employment still not fully understood.

Lipids shape brain function through ion channel and receptor modulations: physiological mechanisms and clinical perspectives.

Lipids represent the most abundant molecular type in the brain with a fat content of approximately 60% of the dry brain weight in humans. Despite this fact, little attention has been paid to circumscribe the dynamic role of lipids in brain function and disease. Membrane lipids such as cholesterol, phosphoinositide, sphingolipids, arachidonic acid and endocannabinoids finely regulate both synaptic receptors and ion channels that insure critical neural functions. After a brief introduction on brain lipids and their respective properties, we review here their role in regulating synaptic function and ion channel activity, action potential propagation, neuronal development, functional plasticity and their contribution in the development of neurological and neuropsychiatric diseases. We also provide possible directions for future research on lipid function in brain plasticity and diseases.

The Relationship between Muscarinic and Cannabinoid Receptors in Neuronal Excitability and Epilepsy: A Review.

Background: Of the seventy million people who suffer from epilepsy, 40 percent of them become resistant to more than one antiepileptic medication and have a higher chance of death. While the classical definition of epilepsy was due to the imbalance between excitatory glutamatergic and inhibitory γ-aminobutyric acid (GABA)-ergic signalling, substantial evidence implicates muscarinic receptors in the regulation of neural excitability. Summary: Cannabinoids have shown to reduce seizure activity and neuronal excitability in several epileptic models through the activation of muscarinic receptors with drugs which modulate their activity. Cannabinoids also have been effective in reducing antiepileptic activity in pharmaco-resistant individuals; however, the mechanism of its effects in temporal lobe epilepsy is not clear. Key Messages: This review seeks to elucidate the relationship between muscarinic and cannabinoid receptors in epilepsy and neural excitability.

Cannabidiol effects on fear processing and implications for PTSD: Evidence from rodent and human studies.

Cannabidiol (CBD) modulates aversive memory and its extinction, with potential implications for treating anxiety- and stress-related disorders. Here, we summarize and discuss scientific evidence showing that CBD administered after the acquisition (consolidation) and retrieval (reconsolidation) of fear memory attenuates it persistently in rats and mice. CBD also reduces fear expression and enhances fear extinction. These effects involve the activation of cannabinoid type-1 (CB1) receptors in the dorsal hippocampus, bed nucleus of stria terminalis, and medial prefrontal cortex, comprising the anterior cingulate, prelimbic, and infralimbic subregions. Serotonin type-1A (5-HT1A) receptors also mediate some CBD effects on fear memory. CBD effects on fear memory acquisition vary, depending on the aversiveness of the conditioning procedure. While rodent findings are relatively consistent and encouraging, human studies investigating CBD's efficacy in modulating aversive/traumatic memories are still limited. More studies are needed to investigate CBD's effects on maladaptive, traumatic memories, particularly in post-traumatic stress disorder patients.

Fatty Acid Amides Suppress Proliferation via Cannabinoid Receptors and Promote the Apoptosis of C6 Glioma Cells in Association with Akt Signaling Pathway Inhibition.

A glioma is a type of tumor that acts on the Central Nervous System (CNS) in a highly aggressive manner. Gliomas can occasionally be inaccurately diagnosed and treatments have low efficacy, meaning that patients exhibit a survival of less than one year after diagnosis. Due to factors such as intratumoral cell variability, inefficient chemotherapy drugs, adaptive resistance development to drugs and tumor recurrence after resection, the search continues for new drugs that can inhibit glioma cell growth. As such, analogues of endocannabinoids, such as fatty acid amides (FAAs), represent interesting alternatives for inhibiting tumor growth, since FAAs can modulate several metabolic pathways linked to cancer and, thus, may hold potential for managing glioblastoma. The aim of this study was to investigate the in vitro effects of two fatty ethanolamides (FAA1 and FAA2), synthetized via direct amidation from andiroba oil (Carapa guianensis Aublet), on C6 glioma cells. FAA1 and FAA2 reduced C6 cell viability, proliferation and migratory potential in a dose-dependent manner and were not toxic to normal retina glial cells. Both FAAs caused apoptotic cell death through the loss of mitochondrial integrity (ΔΨm), probably by activating cannabinoid receptors, and inhibiting the PI3K/Akt pathway. In conclusion, FAAs derived from natural products may have the potential to treat glioma-type brain cancer.

Sex-Specific Changes to Brain Fatty Acids, Plasmalogen, and Plasma Endocannabinoids in Offspring Exposed to Maternal and Postnatal High-Linoleic-Acid Diets.

Linoleic acid (LA) is required for neuronal development. We have previously demonstrated sex-specific changes in cardiovascular and hepatic function in rat offspring from mothers consuming a high-LA diet, with some effects associated with reduced LA concentration in the postnatal diet. At this time, the impact of a high-maternal-LA diet on offspring brain development and the potential for the postnatal diet to alter any adverse changes are unknown. Rat offspring from mothers fed low- (LLA) or high-LA (HLA) diets during pregnancy and lactation were weaned at postnatal day 25 (PN25) and fed LLA or HLA diets until sacrifice in adulthood (PN180). In the offspring's brains, the postnatal HLA diet increased docosapentaenoate in males. The maternal HLA diet increased LA, arachidonate, docosapentaenoate, C18:0 dimethylacetal (DMA), C16:0 DMA, C16:0 DMA/C16:0, and C18:0 DMA/C18:0, but decreased eoicosenoate, nervoniate, lignocerate, and oleate in males. Maternal and postnatal HLA diets reduced oleate and vaccenate and had an interaction effect on myristate, palmitoleate, and eicosapentaenoate in males. In females, maternal HLA diet increased eicosadienoate. Postnatal HLA diet increased stearate and docosapentaenoate. Maternal and postnatal HLA diets had an interaction effect on oleate, arachidate, and docosahexaenoic acid (DHA)/omega (n)-6 docosapentaenoic acid (DPA) in females. Postnatal HLA diet decreased DHA/n-6 DPA in males and females. Postnatal HLA diet increased plasma endocannabinoids (arachidonoyl ethanolamide and 2-arachidonoyl glycerol), as well as other N-acyl ethanolamides and testosterone. HLA diet alters brain fatty acids, plasma endocannabinoids, and plasmalogen concentrations in a development-specific and sex-specific manner.

Advances in targeted liquid chromatography-tandem mass spectrometry methods for endocannabinoid and N-acylethanolamine quantification in biological matrices: A systematic review.

Liquid chromatography paired with tandem mass spectrometry (LC-MS/MS) is the gold standard in measurement of endocannabinoid concentrations in biomatrices. We conducted a systematic review of literature to identify advances in targeted LC-MS/MS methods in the period 2017-2024. We found that LC-MS/MS methods for endocannabinoid quantification are relatively consistent both across time and across biomatrices. Recent advances have primarily been in three areas: (1) sample preparation techniques, specific to the chosen biomatrix; (2) the range of biomatrices tested, recently favoring blood matrices; and (3) the breadth of endocannabinoid and endocannabinoid-like analytes incorporated into assays. This review provides a summary of the recent literature and a guide for researchers looking to establish the best methods for quantifying endocannabinoids in a range of biomatrices.

Endocannabinoid analysis in GlucoEXACT plasma: Method validation and sample handling recommendations.

Endocannabinoids (ECs), such as anandamide and 2-arachidonyl glycerol (2-AG), contribute to the pathology of inflammatory, malignant, cardiovascular, metabolic and mental diseases. The reliability of quantitative analyses in biological fluids of ECs and endocannabinoid-like (EC-like) substances depends on pre-analytical conditions such as temperature and "time-to-centrifugation". Standardization of these parameters is critical for valid quantification and implementation in clinical research. In this study, we compared concentrations obtained with GlucoEXACT blood collection tubes versus K3EDTA tubes and employed the optimized procedure to assess ECs profiles in patients with inflammatory skin disease and healthy controls. A UHPLC-MS/MS method was validated for human plasma from GlucoEXACT blood collection tubes according to EMA and FDA guidelines, and pre-analytical conditions were systematically modified to assess analyte stability and optimize the procedures. The results showed significantly lower concentrations of ECs and EC-like substance concentrations with GlucoEXACT tubes compared with K3EDTA tubes, and GlucoEXACT extended the time window of stable concentrations. The strongest method-disagreement occurred for 1/2-AG suggesting that GlucoEXACT delayed ex vivo isomer rearrangement. Hence, GlucoExact tubes were superior in terms of stability and reliability. However, although absolute concentrations obtained with GlucoExact and K3EDTA differed, linear regression studies showed high agreement (except for 1/2-AG), and both methods showed similar EC profiles and similar disease-dependent pro-inflammatory patterns in dermatology patients. Hence, despite the obstacles in EC analyses, implementation of optimized pre-analytical blood collection and sample processing procedures provide reliable insight into peripheral ECs.

Examination of the Effect of Dimethyl Trisulfide in Acute Stress Mouse Model with the Potential Involvement of the TRPA1 Ion Channel.

Polysulfides are endogenously produced in mammals and generally associated with protective functions. Our aim was to investigate the effect of dimethyl trisulfide (DMTS) in a mouse model of acute stress. DMTS activates transient receptor potential ankyrin 1 (TRPA1) channels and leads to neuropeptide release, potentially that of substance P (SP). We hypothesize that DMTS might inhibit the degrading enzymes of endocannabinoids, so this system was also investigated as another possible pathway for mediating the effects of DMTS. Trpa1 gene wild-type (WT) and knockout (KO) mice were used to confirm the role of the TRPA1 ion channel in mediating the effects of DMTS. C57BL/6J, NK1 gene KO, and Tac1 gene KO mice were used to evaluate the effect of DMTS on the release and expression of SP. Some C57BL/6J animals were treated with AM251, an inhibitor of the cannabinoid CB1 receptor, to elucidate the role of the endocannabinoid system in these processes. Open field test (OFT) and forced swim test (FST) were performed in each mouse strain. A tail suspension test (TST) was performed in Trpa1 WT and KO animals. C-FOS immunohistochemistry was carried out on Trpa1 WT and KO animals. The DMTS treatment increased the number of highly active periods and decreased immobility time in the FST in WT animals, but had no effect on the Trpa1 KO mice. The DMTS administration induced neuronal activation in the Trpa1 WT mice in the stress-related brain areas, such as the locus coeruleus, dorsal raphe nucleus, lateral septum, paraventricular nucleus of the thalamus, and paraventricular nucleus of the hypothalamus. DMTS may have a potential role in the regulation of stress-related processes, and the TRPA1 ion channel may also be involved in mediating the effects of DMTS. DMTS can be an ideal candidate for further study as a potential remedy for stress-related disorders.

Anandamide Modulates Thermal Avoidance in Caenorhabditis elegans Through Vanilloid and Cannabinoid Receptor Interplay.

Understanding the endocannabinoid system in C. elegans may offer insights into basic biological processes and potential therapeutic targets for managing pain and inflammation in human. It is well established that anandamide modulates pain perception by binding to cannabinoid and vanilloid receptors, regulating neurotransmitter release and neuronal activity. One objective of this study was to demonstrate the suitability of C. elegans as a model organism for assessing the antinociceptive properties of bioactive compounds and learning about the role of endocannabinoid system in C. elegans. The evaluation of the compound anandamide (AEA) revealed antinociceptive activity by impeding C. elegans nocifensive response to noxious heat. Proteomic and bioinformatic investigations uncovered several pathways activated by AEA. Enrichment analysis unveiled significant involvement of ion homeostasis pathways, which are crucial for maintaining neuronal function and synaptic transmission, suggesting AEA's impact on neurotransmitter release and synaptic plasticity. Additionally, pathways related to translation, protein synthesis, and mTORC1 signaling were enriched, highlighting potential mechanisms underlying AEA's antinociceptive effects. Thermal proteome profiling identified NPR-32 and NPR-19 as primary targets of AEA, along with OCR-2, Cathepsin B, Progranulin, Transthyretin, and ribosomal proteins. These findings suggest a complex interplay between AEA and various cellular processes implicated in nociceptive pathways and inflammation modulation. Further investigation into these interactions could provide valuable insights into the therapeutic potential of AEA and its targets for the management of pain-related conditions.

Relationship between sex, APOE genotype, endocannabinoids and cognitive change in older adults with metabolic syndrome during a 3-year Mediterranean diet intervention.

BACKGROUND: The Mediterranean diet (MedDiet) has demonstrated efficacy in preventing age-related cognitive decline and modulating plasma concentrations of endocannabinoids (eCBs) and N-acylethanolamines (NAEs, or eCB-like compounds), which are lipid mediators involved in multiple neurological disorders and metabolic processes. Hypothesizing that eCBs and NAEs will be biomarkers of a MedDiet intervention and will be related to the cognitive response, we investigated this relationship according to sex and apolipoprotein E (APOE) genotype, which may affect eCBs and cognitive performance. METHODS: This was a prospective cohort study of 102 participants (53.9% women, 18.8% APOE-ɛ4 carriers, aged 65.6 ± 4.5 years) from the PREDIMED-Plus-Cognition substudy, who were recruited at the Hospital del Mar Research Institute (Barcelona). All of them presented metabolic syndrome plus overweight/obesity (inclusion criteria of the PREDIMED-Plus) and normal cognitive performance at baseline (inclusion criteria of this substudy). A comprehensive battery of neuropsychological tests was administered at baseline and after 1 and 3 years. Plasma concentrations of eCBs and NAEs, including 2-arachidonoylglycerol (2-AG), anandamide (AEA), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and N-docosahexaenoylethanolamine (DHEA), were also monitored. Baseline cognition, cognitive changes, and the association between eCBs/NAEs and cognition were evaluated according to gender (crude models), sex (adjusted models), and APOE genotype. RESULTS: At baseline, men had better executive function and global cognition than women (the effect size of gender differences was - 0.49, p = 0.015; and - 0.42, p = 0.036); however, these differences became nonsignificant in models of sex differences. After 3 years of MedDiet intervention, participants exhibited modest improvements in memory and global cognition. However, greater memory changes were observed in men than in women (Cohen's d of 0.40 vs. 0.25; p = 0.017). In men and APOE-ε4 carriers, 2-AG concentrations were inversely associated with baseline cognition and cognitive changes, while in women, cognitive changes were positively linked to changes in DHEA and the DHEA/AEA ratio. In men, changes in the OEA/AEA and OEA/PEA ratios were positively associated with cognitive changes. CONCLUSIONS: The MedDiet improved participants' cognitive performance but the effect size was small and negatively influenced by female sex. Changes in 2-AG, DHEA, the OEA/AEA, the OEA/PEA and the DHEA/AEA ratios were associated with cognitive changes in a sex- and APOE-dependent fashion. These results support the modulation of the endocannabinoid system as a potential therapeutic approach to prevent cognitive decline in at-risk populations. TRIAL REGISTRATION: ISRCTN89898870.

Neurolipidomic insights into anxiety disorders: Uncovering lipid dynamics for potential therapeutic advances.

Anxiety disorders constitute a spectrum of psychological conditions affecting millions of individuals worldwide, imposing a significant health burden. Historically, the development of anxiolytic medications has been largely focused on neurotransmitter function and modulation. However, in recent years, neurolipids emerged as a prime target for understanding psychiatric pathogenesis and developing novel medications. Neurolipids influence various neural activities such as neurotransmission and cellular functioning, as well as maintaining cell membrane integrity. Therefore, this review aims to elucidate the alterations in neurolipids associated with an anxious mental state and explore their potential as targets of novel anxiolytic medications. Existing evidence tentatively associates dysregulated neurolipid levels with the etiopathology of anxiety disorders. Notably, preclinical investigations suggest that several neurolipids, including endocannabinoids and polyunsaturated fatty acids, may hold promise as potential pharmacological targets. Overall, the current literature tentatively suggests the involvement of lipids in the pathogenesis of anxiety disorders, hinting at potential prospects for future pharmacological interventions.

A helping HAND: therapeutic potential of MAGL inhibition against HIV-1-associated neuroinflammation.

Background: Human immunodeficiency virus (HIV) affects nearly 40 million people globally, with roughly 80% of all people living with HIV receiving antiretroviral therapy. Antiretroviral treatment suppresses viral load in peripheral tissues but does not effectively penetrate the blood-brain barrier. Thus, viral reservoirs persist in the central nervous system and continue to produce low levels of inflammatory factors and early viral proteins, including the transactivator of transcription (Tat). HIV Tat is known to contribute to chronic neuroinflammation and synaptodendritic damage, which is associated with the development of cognitive, motor, and/or mood problems, collectively known as HIV-associated neurocognitive disorders (HAND). Cannabinoid anti-inflammatory effects are well documented, but therapeutic utility of cannabis remains limited due to its psychotropic effects, including alterations within brain regions encoding reward processing and motivation, such as the nucleus accumbens. Alternatively, inhibiting monoacylglycerol lipase (MAGL) has demonstrated therapeutic potential through interactions with the endocannabinoid system. Methods: The present study utilized a reward-related operant behavioral task to quantify motivated behavior in female Tat transgenic mice treated with vehicle or MAGL inhibitor MJN110 (1 mg/kg). Brain tissue was collected to assess dendritic injury and neuroinflammatory profiles, including dendritic microtubule-associated protein (MAP2ab) intensity, microglia density, microglia morphology, astrocyte density, astrocytic interleukin-1ß (IL-1ß) colocalization, and various lipid mediators. Results: No significant behavioral differences were observed; however, MJN110 protected against Tat-induced dendritic injury by significantly upregulating MAP2ab intensity in the nucleus accumbens and in the infralimbic cortex of Tat(+) mice. No or only minor effects were noted for Iba-1+ microglia density and/or microglia morphology. Further, Tat increased GFAP+ astrocyte density in the infralimbic cortex and GFAP+ astrocytic IL-1ß colocalization in the nucleus accumbens, with MJN110 significantly reducing these measures in Tat(+) subjects. Lastly, selected HETE-related inflammatory lipid mediators in the striatum were downregulated by chronic MJN110 treatment. Conclusions: These findings demonstrate anti-inflammatory and neuroprotective properties of MJN110 without cannabimimetic behavioral effects and suggest a promising alternative to cannabis for managing neuroinflammation.

Different stressors uniquely affect the expression of endocannabinoid-metabolizing enzymes in the central ring ganglia of Lymnaea stagnalis.

The endocannabinoid system (ECS) plays an important role in neuroprotection, neuroplasticity, energy balance, modulation of stress, and inflammatory responses, acting as a critical link between the brain and the body's peripheral regions, while also offering promising potential for novel therapeutic strategies. Unfortunately, in humans, pharmacological inhibitors of different ECS enzymes have led to mixed results in both preclinical and clinical studies. As the ECS has been highly conserved throughout the eukaryotic lineage, the use of invertebrate model organisms like the pond snail Lymnaea stagnalis may provide a flexible tool to unravel unexplored functions of the ECS at the cellular, synaptic, and behavioral levels. In this study, starting from the available genome and transcriptome of L. stagnalis, we first identified putative transcripts of all ECS enzymes containing an open reading frame. Each predicted protein possessed a high degree of sequence conservation to known orthologues of other invertebrate and vertebrate organisms. Sequences were confirmed by qualitative PCR and sequencing. Then, we investigated the transcriptional effects induced by different stress conditions (i.e., bacterial LPS injection, predator scent, food deprivation, and acute heat shock) on the expression levels of the enzymes of the ECS in Lymnaea's central ring ganglia. Our results suggest that in Lymnaea as in rodents, the ECS is involved in mediating inflammatory and anxiety-like responses, promoting energy balance, and responding to acute stressors. To our knowledge, this study offers the most comprehensive analysis so far of the ECS in an invertebrate model organism.

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.

Interactions between physical exercise, associative memory, and genetic risk for Alzheimer's disease.

The ε4 allele of the APOE gene heightens the risk of late onset Alzheimer's disease. ε4 carriers, may exhibit cognitive and neural changes early on. Given the known memory-enhancing effects of physical exercise, particularly through hippocampal plasticity via endocannabinoid signaling, here we aimed to test whether a single session of physical exercise may benefit memory and underlying neurophysiological processes in young ε3 carriers (ε3/ε4 heterozygotes, risk group) compared with a matched control group (homozygotes for ε3). Participants underwent fMRI while learning picture sequences, followed by cycling or rest before a memory test. Blood samples measured endocannabinoid levels. At the behavioral level, the risk group exhibited poorer associative memory performance, regardless of the exercising condition. At the brain level, the risk group showed increased medial temporal lobe activity during memory retrieval irrespective of exercise (suggesting neural compensatory effects even at baseline), whereas, in the control group, such increase was only detectable after physical exercise. Critically, an exercise-related endocannabinoid increase correlated with task-related hippocampal activation in the control group only. In conclusion, healthy young individuals carrying the ε4 allele may present suboptimal associative memory performance (when compared with homozygote ε3 carriers), together with reduced plasticity (and functional over-compensation) within medial temporal structures.

Alterations in plasma endocannabinoid concentrations among individuals with major depression treated with electroconvulsive therapy.

The role of the endocannabinoid system (ECS) in depression and suicidality has recently emerged. The purpose of the study was to identify changes in plasma endocannabinoid concentrations of several endocannabinoids and correlate them with depressive symptoms and suicidality in patients with severe major depression undergoing electroconvulsive therapy (ECT). The study included 17 patients that were evaluated in four visits at different stages of therapy. At each visit depression, anxiety and suicidality symptoms were assessed and blood samples collected. Several endocannabinoid concentrations increased following six sessions of ECT, as 2-AG (p < 0.05) and LEA (p < 0.01), and following twelve sessions of ECT, as 2-AG (p < 0.05), AEA (p < 0.05), LEA (p < 0.05) and DH-Gly (p < 0.05). Endocannabinoids also correlated with symptoms of depression, anxiety and suicidality at baseline and at the sixth ECT session. Finally, we found one endocannabinoid, l-Gly, that differentiated between remitted and not-remitted patients at the seventh and thirteenth ECT sessions (p < 0.05). Our findings suggest that depression is markedly related to imbalance of the endocannabinoid system, and further regulated by ECT. Plasma endocannabinoids could be promising biomarkers for detection of depression response and remission.