Supplementation of omega 3 fatty acids improves oxidative stress in activated BV2 microglial cell line

Non-psychotropic Cannabis sativa L. phytocomplex modulates microglial inflammatory response through CB2 receptors-, endocannabinoids-, and NF-κB-mediated signaling

Cannabis sativa L. is increasingly emerging for its protective role in modulating neuroinflammation, a complex process orchestrated among others by microglia, the resident immune cells of the central nervous system. Phytocannabinoids, especially cannabidiol (CBD), terpenes, and other constituents trigger several upstream and downstream microglial intracellular pathways. Here, we investigated the molecular mechanisms of a CBD- and terpenes-enriched C. sativa extract (CSE) in an in vitro model of neuroinflammation. We evaluated the effect of CSE on the inflammatory response induced by exposure to lipopolysaccharide (LPS) in BV-2 microglial cells, compared with CBD and β-caryophyllene (CAR), CB2 receptors (CB2r) inverse and full agonist, respectively. The LPS-induced upregulation of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α was significantly attenuated by CSE and only partially by CBD, whereas CAR was ineffective. In BV-2 cells, these anti-inflammatory effects exerted by CSE phytocomplex were only partially dependent on CB2r modulation and they were mediated by the regulation of enzymes responsible for the endocannabinoids metabolism, by the inhibition of reactive oxygen species release and the modulation of JNK/p38 cascade with consequent NF-κB p65 nuclear translocation suppression. Our data suggest that C. sativa phytocomplex and its multitarget mechanism could represent a novel therapeutic strategy for neuroinflammatory-related diseases.

Role of Phytoconstituents as PPAR Agonists: Implications for Neurodegenerative Disorders

Peroxisome proliferator-activated receptors (PPAR-γ, PPAR-α, and PPAR-β/δ) are ligand-dependent nuclear receptors that play a critical role in the regulation of hundreds of genes through their activation. Their expression and targeted activation play an important role in the treatment of a variety of diseases, including neurodegenerative, cardiovascular, diabetes, and cancer. In recent years, several reviews have been published describing the therapeutic potential of PPAR agonists (natural or synthetic) in the disorders listed above; however, no comprehensive report defining the role of naturally derived phytoconstituents as PPAR agonists targeting neurodegenerative diseases has been published. This review will focus on the role of phytoconstituents as PPAR agonists and the relevant preclinical studies and mechanistic insights into their neuroprotective effects. Exemplary research includes flavonoids, fatty acids, cannabinoids, curcumin, genistein, capsaicin, and piperine, all of which have been shown to be PPAR agonists either directly or indirectly. Additionally, a few studies have demonstrated the use of clinical samples in in vitro investigations. The role of the fruit fly Drosophila melanogaster as a potential model for studying neurodegenerative diseases has also been highlighted.

Dietary Fish Hydrolysate Improves Memory Performance Through Microglial Signature Remodeling During Aging

Brain aging is characterized by a chronic low-grade inflammation, which significantly impairs cognitive function. Microglial cells, the immunocompetent cells of the brain, present a different phenotype, switching from a homeostatic signature (M0) to a more reactive phenotype called “MGnD” (microglial neurodegenerative phenotype), leading to a high production of pro-inflammatory cytokines. Furthermore, microglial cells can be activated by age-induced gut dysbiosis through the vagus nerve or the modulation of the peripheral immune system. Nutrients, in particular n-3 long chain polyunsaturated fatty acids (LC-PUFAs) and low molecular weight peptides, display powerful immunomodulatory properties, and can thus prevent age-related cognitive decline. The objective of this study was to investigate the effects of n-3 LC-PUFAs and low molecular weight peptides contained in a marine by-product-derived hydrolysate on microglial phenotypes and intestinal permeability and their consequences on cognition in mice. We demonstrated that the hydrolysate supplementation for 8 weeks prevented short- and long-term memory decline during aging. These observations were linked to the modulation of microglial signature. Indeed, the hydrolysate supplementation promoted homeostatic microglial phenotype by increasing TGF-β1 expression and stimulated phagocytosis by increasing Clec7a expression. Moreover, the hydrolysate supplementation promoted anti-inflammatory intestinal pathway and tended to prevent intestinal permeability alteration occurring during aging. Therefore, the fish hydrolysate appears as an interesting candidate to prevent cognitive decline during aging.

New Insights into Depressive Disorder with Respect to Low-Grade Inflammation and Fish Oil Intake

Unipolar depression has been recognized as one of the major diseases by the World Health Organization in the 21st century. The etiology of depression is complicated and includes genetic factors, stress, aging, and special physical status (pregnancy, metabolic syndrome, and trauma). Numerous animal and human studies have demonstrated that n-3 polyunsaturated fatty acids (n-3 PUFAs) are highly correlated to cognition and depression. These nutritional antidepressants, including EPA and DHA, have a range of neurobiological activities contributing to their potential antidepressant effects. Our preclinical and clinical studies have indicated that n-3 PUFA supplementation in addition to standard antidepressant medications may provide synergistic neuroprotective and antioxidant/inflammatory effects. To translate our preliminary findings into clinical application, this paper reviews the existing evidence on the antidepressant effects of n-3 PUFAs and the potential underlying mechanisms, which include modulation of chronic lowgrade inflammation and the corresponding changes in peripheral blood immune biomarkers.

The emerging role of probiotics in neurodegenerative diseases: new hope for Parkinson's disease?

Neurodegenerative disease etiology is still unclear, but different contributing factors, such as lifestyle and genetic factors are involved. Altered components of the gut could play a key role in the gut-brain axis, which is a bidirectional system between the central nervous system and the enteric nervous system. Variations in the composition of the gut microbiota and its function between healthy people and patients have been reported for a variety of human disorders comprising metabolic, autoimmune, cancer, and, notably, neurodegenerative disorders. Diet can alter the microbiota composition, affecting the gut-brain axis function. Different nutraceutical interventions have been devoted to normalizing gut microbiome dysbiosis and to improving biological outcomes in neurological conditions, including the use of probiotics. Preclinical and clinical investigations discussed in this review strengthen the correlation between intestinal microbiota and brain and the concept that modifying the microbiome composition may improve brain neurochemistry, modulating different pathways. This review will discuss the potential use of probiotics for Parkinson's disease prevention or treatment or as adjuvant therapy, confirming that gut microbiota modulation influences different pro-survival pathways. Future investigations in Parkinson's disease should consider the role of the gut-brain axis and additional comprehension of the underlying mechanisms is extremely necessary.

Phosphoinositides signaling modulates microglial actin remodeling and phagocytosis in Alzheimer's disease

Alzheimer's disease is one of the neurodegenerative diseases, characterized by the accumulation of abnormal protein deposits, which disrupts signal transduction in neurons and other glia cells. The pathological protein in neurodegenerative diseases, Tau and amyloid-β contribute to the disrupted microglial signaling pathways, actin cytoskeleton, and cellular receptor expression. The important secondary messenger lipids i.e., phosphatidylinositols are largely affected by protein deposits of amyloid-β in Alzheimer's disease. Phosphatidylinositols are the product of different phosphatidylinositol kinases and the state of phosphorylation at D3, D4, and D5 positions of inositol ring. Phosphatidylinositol 3,4,5-triphosphate (PI 3, 4, 5-P3) involves in phagocytic cup formation, cell polarization, whereas Phosphatidylinositol 4,5-bisphosphate (PI 4, 5-P2)-mediates the process of phagosomes formation and further its fusion with early endosome.. The necessary activation of actin-binding proteins such as Rac, WAVE complex, and ARP2/3 complex for the actin polymerization in the process of phagocytosis, migration is regulated and maintained by PI 3, 4, 5-P3 and PI 4, 5-P2. The ratio and types of fatty acid intake can influence the intracellular secondary lipid messengers along with the cellular content of phaphatidylcholine and phosphatidylethanolamine. The Amyloid-β deposits and extracellular Tau seeds disrupt phosphatidylinositides level and actin cytoskeletal network that hamper microglial-signaling pathways in AD. We hypothesize that being a lipid species intracellular levels of phosphatidylinositol would be regulated by dietary fatty acids. Further we are interested to understand phosphoinositide-based signaling cascades in phagocytosis and actin remodeling. Video Abstract.

Walnut-Associated Fatty Acids Inhibit LPS-Induced Activation of BV-2 Microglia

Walnuts have high levels of the omega-3 fatty acid alpha-linolenic acid (C18:3n-3, ALA) and the omega-6 fatty acid linoleic acid (C18:2n-6, LA). Previous research has demonstrated that pre-treatment of BV-2 microglia with walnut extract inhibited lipopolysaccharide (LPS)-induced activation of microglia. As an extension of that study, the effects of walnut-associated fatty acids on BV-2 microglia were assessed. BV-2 murine microglia cells were treated with LA, ALA, or a combination of LA+ALA prior to or after exposure to LPS. Nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) were measured in cell-conditioned media. Cyclooxeganse-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression were assessed in BV-2 microglia. Both LA and ALA protected against LPS-induced increases in NO, iNOS, COX-2, and TNF-alpha when used before LPS exposure. When BV-2 microglia were treated with fatty acids after LPS, only COX-2 and TNF-alpha were significantly attenuated by the fatty acids. There was no synergism of LA+ALA, as the LA+ALA combination was no more effective than LA or ALA alone. Fatty acids, like those found in walnuts, may protect against production of cytotoxic intermediates and cell-signaling molecules from microglia and may prove beneficial for preventing age- or disease-related neurodegeneration.

BV-2 Microglial Cells Respond to Rotenone Toxic Insult by Modifying Pregnenolone, 5α-Dihydroprogesterone and Pregnanolone Levels

Neuroinflammation, whose distinctive sign is the activation of microglia, is supposed to play a key role in the development and progression of neurodegenerative diseases. The aim of this investigation was to determine levels of neurosteroids produced by resting and injured BV-2 microglial cells. BV-2 cells were exposed to increasing concentrations of rotenone to progressively reduce their viability by increasing reactive oxygen species (ROS) production. BV-2 cell viability was significantly reduced 24, 48 and 72 h after rotenone (50-1000 nM) exposure. Concomitantly, rotenone (50-100 nM) determined a dose-independent augmentation of ROS production. Then, BV-2 cells were exposed to a single, threshold dose of rotenone (75 nM) to evaluate the overtime release of neurosteroids. In particular, pregnenolone, pregnenolone sulfate, progesterone, 5α-dihydroprogesterone (5α-DHP), allopregnanolone, and pregnanolone, were quantified in the culture medium by liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. BV-2 cells synthesized all the investigated neurosteroids and, after exposure to rotenone, 5αDHP and pregnanolone production was remarkably increased. In conclusion, we found that BV-2 cells not only synthesize several neurosteroids, but further increase this production following oxidative damage. Pregnanolone and 5α-DHP may play a role in modifying the progression of neuroinflammation in neurodegenerative diseases.

Salmo salar fish waste oil: Fatty acids composition and antibacterial activity

BACKGROUND AND AIMS

Fish by-products are generally used to produce fishmeal or fertilizers, with fish oil as a by-product. Despite their importance, fish wastes are still poorly explored and characterized and more studies are needed to reveal their potentiality. The goal of the present study was to qualitatively characterize and investigate the antimicrobial effects of the fish oil extracted from Salmo salar waste samples and to evaluate the potential use of these compounds for treating pathogen infections.

METHODS

Salmo salar waste samples were divided in two groups: heads and soft tissues. Fatty acids composition, and in particular the content in saturated (SAFAs), mono-unsaturated (MUFAs) and Polyunsaturated (PUFAs) fatty acids, was characterized through GC/MS Thermo Focus GC-DSQ II equipped with a ZB-5 fused silica capillary tubes column. The antimicrobial activity of the salmon waste oils was evaluated through the Minimum Inhibitory Concentration assay and the antibiotics contamination was determined by Liquid Chromatography with tandem Mass Spectrometry (LC-MS/MS) analysis. All experiments were done at least in triplicate.

RESULTS

GC/MS analysis has shown the specific fatty acid composition of the salmon waste oils and their enrichment in MUFAs and PUFAs, with special reference to omega-3, -6, -7, -9 fatty acids. Furthermore, our study has highlighted the antimicrobial activity of the fish waste oil samples against two Gram+ and Gram- bacterial strains.

CONCLUSIONS

These data confirm that the fish waste is still quantitatively and qualitatively an important source of available biological properties that could be extracted and utilized representing an important strategy to counteract infective diseases in the context of the circular economy.

N-3 Polyunsaturated Fatty Acids and the Resolution of Neuroinflammation

In the past few decades, as a result of their anti-inflammatory properties, n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs), have gained greater importance in the regulation of inflammation, especially in the central nervous system (in this case known as neuroinflammation). If sustained, neuroinflammation is a common denominator of neurological disorders, including Alzheimer’s disease and major depression, and of aging. Hence, limiting neuroinflammation is a real strategy for neuroinflammatory disease therapy and treatment. Recent data show that n-3 LC-PUFAs exert anti-inflammatory properties in part through the synthesis of specialized pro-resolving mediators (SPMs) such as resolvins, maresins and protectins. These SPMs are crucially involved in the resolution of inflammation. They could be good candidates to resolve brain inflammation and to contribute to neuroprotective functions and could lead to novel therapeutics for brain inflammatory diseases. This review presents an overview 1) of brain n-3 LC-PUFAs as precursors of SPMs with an emphasis on the effect of n-3 PUFAs on neuroinflammation, 2) of the formation and action of SPMs in the brain and their biological roles, and the possible regulation of their synthesis by environmental factors such as inflammation and nutrition and, in particular, PUFA consumption.

Direct and indirect effects of lipids on microglia function

Microglia are key players in brain function by maintaining brain homeostasis across lifetime. They participate to brain development and maturation through their ability to release neurotrophic factors, to remove immature synapses or unnecessary neural progenitors. They modulate neuronal activity in healthy adult brains and they also orchestrate the neuroinflammatory response in various pathophysiological contexts such as aging and neurodegenerative diseases. One of the main features of microglia is their high sensitivity to environmental factors, partly via the expression of a wide range of receptors. Recent data pinpoint that dietary fatty acids modulate microglia function. Both the quantity and the type of fatty acid are potent modulators of microglia physiology. The present review aims at dissecting the current knowledge on the direct and indirect mechanisms (focus on gut microbiota and hormones) through which fatty acids influence microglial physiology. We summarize main discoveries from in vitro and in vivo models on fatty acid-mediated microglial modulation. All these studies represent a promising field of research that could promote using nutrition as a novel therapeutic or preventive tool in diseases involving microglia dysfunctions.

Frailty, Cognitive Decline, Neurodegenerative Diseases and Nutrition Interventions

Currently the human population is aging faster. This leads to higher dependency rates and the transformation of health and social care to adapt to this aged population. Among the changes developed by this population is frailty. It is defined as a clinically detectable syndrome, related to the aging of multiple physiological systems, which prompts a situation of vulnerability. The etiology of frailty seems to be multifactorial and its pathophysiology is influenced by the interaction of numerous factors. Morley et al. propose four main mechanisms triggering the frailty: atherosclerosis, sarcopenia, cognitive deterioration and malnutrition, with their respective metabolic alterations. Malnutrition is associated with cognitive impairment or functional loss, but it is also known that an inadequate nutritional status predisposes to cognitive frailty. Additionally, nutritional factors that may influence vascular risk factors will potentially have an effect on dementia decline among patients with cognitive frailty. This review aims to describe the nutritional factors that have been researched so far which may lead to the development of frailty, and especially cognitive decline.

Hyperlocomotion and anxiety- like behavior induced by binge ethanol exposure in rat neonates. Possible ameliorative effects of Omega 3

Maternal alcohol consumption during pregnancy may cause neurocognitive and behavioral disorders that can persist until adulthood. Epidemiological data has revealed an alarming increase in the frequency of alcohol intake in pregnant women. Nutritional variables may also have an impact on the behavioral alterations occasioned by alcohol during development. Moreover, omega-3, a polyunsaturated fatty acid necessary for normal brain development, is deficient in ethanol-treated animals. Although studies have shown that omega-3 supplementation after prenatal ethanol (EtOH) treatment improves some disorders, there are no reports about acute treatment with omega-3 in binge alcohol neurotoxic models during postnatal development. The goal of this study was to determine whether an administration of omega-3, after an acute ethanol dose in neonates, would be able to attenuate alcohol effects in offspring. Male/ female rats were administered ethanol (2.5 g/kg s.c. at 0 and 2 h) or saline on postnatal day (PND) 7, with a single dose of omega-3 (720 mg/kg) 15 min after the last alcohol injection. It was have found that EtOH-treated animals showed hyperlocomotion on PND 14 (pre-juvenile), and anxiety-like behavior was observed at all the three ages studied. Administration of omega-3 after EtOH treatment reduced hyperlocomotion and the anxiety-like behaviors on PND 14, but did not diminish the anxiety on either PND 20 or 30 (juvenile). In conclusion, acute ethanol exposure produced neurobehavioral alterations that persisted in the offspring, with omega-3 able to ameliorate these effects on PND 14. These data are relevant considering that omega-3 administration may have therapeutic effects through mitigating some of ethanol´s damaging consequences.

Neuroinflammation in hypertension: the renin-angiotensin system versus pro-resolution pathways

Overstimulation of the pro-inflammatory pathways within brain areas responsible for sympathetic outflow is well evidenced as a primary contributing factor to the establishment and maintenance of neurogenic hypertension. However, the precise mechanisms and stimuli responsible for promoting a pro-inflammatory state are not fully elucidated. Recent work has unveiled novel compounds derived from omega-3 polyunsaturated fatty acids (ω-3 PUFAs), termed specialized pro-resolving mediators (SPMs), which actively regulate the resolution of inflammation. Failure or dysregulation of the resolution process has been linked to a variety of chronic inflammatory and neurodegenerative diseases. Given the pathologic role of neuroinflammation in the hypertensive state, SPMs and their associated pathways may provide a link between hypertension and the long-standing association of dietary ω-3 PUFAs with cardioprotection. Herein, we review recent progress in understanding the RAS-driven pathophysiology of neurogenic hypertension, particularly in regards to the chronic low-grade neuroinflammatory response. In addition, we examine the potential for an impaired resolution of inflammation process in the context of hypertension.

Modulating Effect of Diet on Alzheimer's Disease

As life expectancy is growing, neurodegenerative disorders, such as Alzheimer's disease, are increasing. This disease is characterised by the accumulation of intracellular neurofibrillary tangles formed by hyperphosphorylated tau protein, senile plaques composed of an extracellular deposit of β-amyloid peptide (Aβ), and neuronal loss. This is accompanied by deficient mitochondrial function, increased oxidative stress, altered inflammatory response, and autophagy process impairment. The present study gathers scientific evidence that demonstrates that specific nutrients exert a direct effect on both Aβ production and Tau processing and their elimination by autophagy activation. Likewise, certain nutrients can modulate the inflammatory response and the oxidative stress related to the disease. However, the extent to which these effects come with beneficial clinical outcomes remains unclear. Even so, several studies have shown the benefits of the Mediterranean diet on Alzheimer's disease, due to its richness in many of these compounds, to which can be attributed their neuroprotective properties due to the pleiotropic effect they show on the aforementioned processes. These indications highlight the potential role of adequate dietary recommendations for clinical management of both Alzheimer's diagnosed patients and those in risk of developing it, emphasising once again the importance of diet on health.

Neuroprotective effects of antioxidants in the management of neurodegenerative disorders: A literature review

It is proven that oxidative stress has a pivotal role in the process of neurodegeneration. The use of antioxidants is an attractive method to prevent the incidence of neurodegenerative diseases. We searched major databases (PubMed, Medline, and Google Scholar) using the keywords of neurodegeneration, oxidative stress, and antioxidant for both review and original studies, which have reported the various beneficial effects of antioxidants. About 70 studies were identified for this review. Among various antioxidants, nine antioxidants with the most applications in research investigations were selected and the major findings concerning their protective effects were reviewed. It is concluded that antioxidants can modify and readjust the oxidative stress in the biological milieu, elicit neuroprotective effects, and positively impact the management of neurodegenerative processes.

Beneficial effects of n-3 polyunsaturated fatty acids administration in a partial lesion model of Parkinson's disease: The role of glia and NRf2 regulation

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been widely associated to beneficial effect over different neurodegenerative diseases. In the present study, we tested the potential therapeutic effect of docohexanoic acid (DHA) and its hydroxylated derivate, DHAH, in a partial lesion model of Parkinson's disease (PD). One month before and four months after the striatal lesion with 6-OHDA was made, the animals were daily treated with DHA (50 mg/kg), DHAH (50 mg/kg), vehicle or saline, by intragastric administration. Animal groups under n-3 PUFA treatments exhibited a trend to improve in amphetamine-induced rotations and cylinder test. The beneficial effect seen in behavioral studies were confirmed with TH immunostaining. TH⁺ fibers and TH⁺ neurons increased in the experimental groups treated with both n-3 PUFAs, DHA and DHAH. Moreover, the n-3 PUFAs administration decreased the astrogliosis and microgliosis, in both the striatum and substantia nigra (SN), with a higher decrease of GFAP⁺ and Iba-1⁺ cells for the DHAH treated group. This experimental group also revealed a positive effect on Nrf2 pathway regulation, decreasing the positive Nrf2 immmunostaining in the striatum and SN, which revealed a potential antioxidant effect of this compound. Taking together, these data suggest a positive effect of n-3 PUFAs administration, and more concretely of DHAH, for PD treatment as it exhibited positive results on dopaminergic system, neuroinflammation and oxidative stress.

Anti-Inflammatory Effects of Schisandrin B on LPS-Stimulated BV2 Microglia via Activating PPAR-γ

Schisandrin B (Sch B), a dibenzocyclooctadiene lignan isolated from Schisandra chinensis (Turcz.) Baill, has been shown to have anti-inflammatory effect. The purpose of this study was to evaluate the effect of Sch B on LPS-induced inflammation in microglia and to investigate the molecular targets of Sch B. BV2 cells were stimulated by LPS in the presence or absence of Sch B. The results showed that the levels of TNF-α, IL-6, IL-1β, and PGE₂ upregulated by LPS were significantly suppressed by Sch B. LPS-induced NF-κB activation was also inhibited by Sch B. Furthermore, Sch B was found to upregulate the expression of PPAR-γ in a concentration-dependent manner. In addition, the inhibition of Sch B on TNF-α, IL-6, IL-1β, and PGE₂ production were reversed by PPAR-γ antagonist GW9662. In conclusion, these results suggested that Sch B inhibited LPS-induced inflammatory response by activating PPAR-γ.

The effects of fish oil on gene expression in patients with polycystic ovary syndrome

BACKGROUND

This study was conducted to determine the effects of fish oil administration on gene expression related to insulin, lipid and inflammation in women with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

This randomized, double-blind, placebo-controlled trial was conducted among 40 subjects with PCOS, aged 18-40 years. Subjects were randomly allocated into two groups to take either 1000 mg omega-3 fatty acids from fish oil (n = 20) or placebo (n = 20) twice a day for 12 weeks. Gene expression related to insulin, lipid and inflammation was quantified in peripheral blood mononuclear cells (PBMC) of PCOS women with RT-PCR method.

RESULTS

Our study demonstrated that after the 12-week intervention, compared with the placebo, fish oil supplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P < .001) in PBMC of subjects with PCOS. In addition, compared to the placebo, taking fish oil supplements downregulated gene expression of interleukin-1 (IL-1) (P = .02) and interleukin-8 (IL-8) (P = .01) in PBMC of subjects with PCOS. We did not observe any significant effect of fish oil supplementation on gene expression of lipoprotein(a) [LP(a)], low-density lipoprotein receptor (LDLR), glucose transporter 1 (GLUT-1), tumour necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-β) in PBMC of subjects with PCOS.

CONCLUSIONS

Overall, fish oil supplementation for 12 weeks to subjects with PCOS significantly improved gene expression of PPAR-γ, IL-1 and IL-8, but did not influence gene expression of LP(a), LDLR, GLUT-1, TNF-α and TGF-β.

Benefits of VCE-003.2, a cannabigerol quinone derivative, against inflammation-driven neuronal deterioration in experimental Parkinson's disease: possible involvement of different binding sites at the PPARγ receptor

BACKGROUND

Neuroprotection with cannabinoids in Parkinson's disease (PD) has been afforded predominantly with antioxidant or anti-inflammatory cannabinoids. In the present study, we investigated the anti-inflammatory and neuroprotective properties of VCE-003.2, a quinone derivative of the non-psychotrophic phytocannabinoid cannabigerol (CBG), which may derive its activity at the peroxisome proliferator-activated receptor-γ (PPARγ). The compound is also an antioxidant.

METHODS

We evaluated VCE-003.2 in an in vivo [mice subjected to unilateral intrastriatal injections of lipopolysaccharide (LPS)] model of PD, as well as in in vitro (LPS-exposed BV2 cells and M-213 cells treated with conditioned media generated from LPS-exposed BV2 cells) cellular models. The type of interaction of VCE-003.2 at the PPARγ receptor was furtherly investigated in bone marrow-derived human mesenchymal stem cells (MSCs) and sustained with transcriptional assays and in silico docking studies.

RESULTS

VCE-003.2 has no activity at the cannabinoid receptors, a fact that we confirmed in this study using competition studies. The administration of VCE-003.2 to LPS-lesioned mice attenuated the loss of tyrosine hydroxylase (TH)-containing nigrostriatal neurons and, in particular, the intense microgliosis provoked by LPS in the substantia nigra, measured by Iba-1/Cd68 immunostaining. The analysis by qPCR of proinflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS) in the striatum showed they were markedly elevated by the LPS lesion and strongly reduced by the treatment with VCE-003.2. The effects of VCE-003.2 in LPS-lesioned mice implied the activation of PPARγ receptors, as they were attenuated when VCE-003.2 was co-administered with the PPARγ inhibitor T0070907. We then moved to some in vitro approaches, first to confirm the anti-inflammatory profile of VCE-003.2 in cultured BV2 cells exposed to LPS. VCE-003.2 was able to attenuate the synthesis and release of TNF-α and IL-1β, as well as the induction of iNOS and cyclooxygenase-2 (COX-2) elicited by LPS in these cells. However, we found such effects were not reversed by GW9662, another classic PPARγ antagonist. Next, we investigated the neuroprotective effects of VCE-003.2 in cultured M-213 neuronal cells exposed to conditioned media generated from LPS-exposed cultured BV2 cells. VCE-003.2 reduced M-213 cell death, but again, such effects were not reversed by T0070907. Using docking analysis, we detected that VCE-003.2 binds both the canonical and the alternative binding sites in the PPARγ ligand-binding pocket (LBP). Functional assays further showed that T0070907 almost abolished PPARγ transcriptional activity induced by rosiglitazone (RGZ), but it did not affect the activity of VCE-003.2 in a Gal4-Luc system. However, T0070907 inhibited the effects of RGZ and VCE-003.2 on the expression of PPARγ-dependent genes upregulated in MSCs.

CONCLUSIONS

We have demonstrated that VCE-003.2 is neuroprotective against inflammation-driven neuronal damage in an in vivo model of PD and in in vitro cellular models of neuroinflammation. Such effects might involve PPARγ receptors, although in silico and in vitro experiments strongly suggest that VCE-003.2 targets PPARγ by acting through two binding sites at the LBP, one that is sensitive to T0070907 (canonical binding site) and other that is not affected by this PPARγ antagonist (alternative binding site).

Anti-Inflammatory Effects of Omega-3 Fatty Acids in the Brain: Physiological Mechanisms and Relevance to Pharmacology

Classically, polyunsaturated fatty acids (PUFA) were largely thought to be relatively inert structural components of brain, largely important for the formation of cellular membranes. Over the past 10 years, a host of bioactive lipid mediators that are enzymatically derived from arachidonic acid, the main n-6 PUFA, and docosahexaenoic acid, the main n-3 PUFA in the brain, known to regulate peripheral immune function, have been detected in the brain and shown to regulate microglia activation. Recent advances have focused on how PUFA regulate the molecular signaling of microglia, especially in the context of neuroinflammation and behavior. Several active drugs regulate brain lipid signaling and provide proof of concept for targeting the brain. Because brain lipid metabolism relies on a complex integration of diet, peripheral metabolism, including the liver and blood, which supply the brain with PUFAs that can be altered by genetics, sex, and aging, there are many pathways that can be disrupted, leading to altered brain lipid homeostasis. Brain lipid signaling pathways are altered in neurologic disorders and may be viable targets for the development of novel therapeutics. In this study, we discuss in particular how n-3 PUFAs and their metabolites regulate microglia phenotype and function to exert their anti-inflammatory and proresolving activities in the brain.

Bioactive lipids as new class of microglial modulators: When nutrition meets neuroimunology

Within the central nervous system the traditional role of microglia has been in brain infection and disease, phagocytosing debris and secreting factors to modify disease progression. More recently, microglia have been found to be important for normal brain development, circuit refinement, and synaptic plasticity in ways that were previously unsuspected. Hence, the brain innate immune system appears to be key in all situations, ranging from physiology to pathology. This unique feature of microglia is established by the wide array of receptors it is equipped with to sense molecular patterns. This includes receptors to most if not all neurotransmitters, neuromodulators and purines. We here review novel, yet extensive literature on a new class of microglia modulators, namely bioactive fatty acids. These lipids are issued from metabolism of nutrients and can cross the blood brain barrier to reach the CNS. They appear to be direct modulators of microglial activity, triggering/inhibiting inflammatory processes or enhancing/inhibiting the ability of these cells to respond to hazardous agents.

Combination of EPA with Carotenoids and Polyphenol Synergistically Attenuated the Transformation of Microglia to M1 Phenotype Via Inhibition of NF-κB

Microglia activation toward the M1 phenotype has been reported to contribute to the neurodegenerative processes and cognition alterations due to the release of pro-inflammatory mediators and cytokines. The aim of the present research was to assess the effectiveness of free fatty acids omega-3 preparations: eicosapentaenoic acid (EPA) or/and docosahexaenoic acid (DHA), carotenoids and phenolics combinations, in inhibiting the release of inflammatory mediators from activated microglia. Preincubation of BV-2 microglia cells with each of the FFAs omega-3 preparations in a range of 0.03-2 μM together with Lyc-O-mato^® (0.1 μM), Carnosic acid (0.2 μM) with or without Lutein (0.2 μM), 1 h before addition of lipopolysaccharide (LPS) for 16 h caused a synergistic inhibition of nitric oxide (NO) production with a rank order of EPA > Ropufa (EPA/DHA 2/1) > Krill (EPA/DHA 1.23/1). The optimal inhibitory combinations of EPA (0.125 μM) with the phytonutrients caused a synergistic inhibition of prostaglandin E₂ (PGE₂) release, IL-6 secretion, superoxide and NO production and prevention of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) upregulation and elevated CD40 expression in microglia exposed to LPS or interferon-γ (IFN-γ), representing infection or inflammation, respectively. The presence of the combination caused a synergistic increase in the release of the anti-inflammatory cytokine IL-10. The inhibitory effects by the combinations of EPA with the phytonutrients were mediated by the inhibition of the redox-sensitive NF-κB activation and detected by its phosphorylated p-65 on serine 536 in microglia stimulated by either LPS or IFN-γ. In addition, phosphorylated CREB on serine 133 which was shown to be involved in the induction of iNOS was inhibited by the combinations in stimulated cells. In conclusion, the results suggest that low concentrations of EPA with the phytonutrients are very efficient in inhibiting the transformation of microglia to M1 phenotype and may prevent cognition deficit.

Natural Docosahexaenoic Acid in the Triglyceride Form Attenuates In Vitro Microglial Activation and Ameliorates Autoimmune Encephalomyelitis in Mice

Many neurodegenerative diseases are associated, at least in part, to an inflammatory process in which microglia plays a major role. The effect of the triglyceride form of the omega-3 polyunsaturated fatty acid docosahexaenoic acid (TG-DHA) was assayed in vitro and in vivo to assess the protective and anti-inflammatory activity of this compound. In the in vitro study, BV-2 microglia cells were previously treated with TG-DHA and then activated with Lipopolysaccharide (LPS) and Interferon-gamma (IFN-γ). TG-DHA treatment protected BV-2 microglia cells from oxidative stress toxicity attenuating NO production and suppressing the induction of inflammatory cytokines. When compared with DHA in the ethyl-ester form, a significant difference in the ability to inhibit NO production in favor of TG-DHA was observed. TG-DHA inhibited significantly splenocyte proliferation but isolated CD4+ lymphocyte proliferation was unaffected. In a mice model of autoimmune encephalomyelitis (EAE), 250 mg/kg/day oral TG-DHA treatment was associated with a significant amelioration of the course and severity of the disease as compared to untreated animals. TG-DHA-treated EAE mice showed a better weight profile, which is a symptom related to a better course of encephalomyelitis. TG-DHA may be a promising therapeutic agent in neuroinflammatory processes and merit to be more extensively studied in human neurodegenerative disorders.

Microglia energy metabolism in metabolic disorder

Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This non-signaling energy demand increases after activation by pathogens, neuronal damage or other kinds of stimulation. Of the three major energy substrates - glucose, fatty acids and glutamine - glucose is crucial for microglia survival and several glucose transporters are expressed to supply sufficient glucose influx. Fatty acids are another source of energy for microglia and have also been shown to strongly influence microglial immune activity. Glutamine, although possibly suitable for use as an energy substrate by microglia, has been shown to have neurotoxic effects when overloaded. Microglial fuel metabolism might be associated with microglial reactivity under different pathophysiological conditions and a microglial fuel switch may thus be the underlying cause of hypothalamic dysregulation, which is associated with obesity.

A review of recent evidence in human studies of n-3 and n-6 PUFA intake on cardiovascular disease, cancer, and depressive disorders: does the ratio really matter?

Polyunsaturated fatty acids (PUFAs) have been considered of great interest for human health due to their potential anti-inflammatory action that may protect from a number of chronic-degenerative diseases with an inflammatory pathogenesis. This review aimed to report the most updated evidence of both n-3 and n-6 PUFAs effect on cardiovascular disease, cancer, and depression in humans. Attention has been also paid to those studies exploring the effects of the ratio intake. Results from pooled analyses of human studies reported a general positive effect of n-3 PUFAs intake on all outcomes considered. In contrast, the role of n-6 PUFAs on human health needs to be better assessed in order to clearly identify which compound exerts beneficial/harmful effects. Only a limited number of clinical studies considered the n-3:n-6 PUFAs ratio, rather reporting contrasting results. A number of limitations when considering the ratio between these two families of PUFAs have risen.