Endocannabinoids drive the acquisition of an alternative phenotype in microglia.

“The ability of microglia to acquire diverse states of activation, or phenotypes, reflects different features that are determinant for their contribution to homeostasis in the adult CNS, and their activity in neuroinflammation, repair or immunomodulation.

Despite the widely reported immunomodulatory effects of cannabinoids in both the peripheral immune system and the CNS, less is known about how the endocannabinoid signaling system (eCBSS) influence the microglial phenotype.

The general aim of the present study was to investigate the role of endocannabinoids in microglia polarization by using microglia cell cultures.

We show that alternative microglia (M2a) and acquired deactivated microglia (M2c) exhibit changes in the eCB machinery that favor the selective synthesis of 2-AG and AEA, respectively.

Once released, these eCBs might be able to act through CB1 and/or CB2 receptors in order to influence the acquisition of an M2 phenotype.

We present three lines of evidence that the eCBSS is critical for the acquisition of the M2 phenotype: (i) M2 polarization occurs on exposure to the two main endocannabinoids 2-AG and AEA in microglia cultures; (ii)cannabinoid receptor antagonists block M2 polarization; and, (iii) M2 polarization is dampened in microglia from CB2 receptor knockout mice.

Taken together, these results indicate the interest of eCBSS for the regulation of microglial activation in normal and pathological conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/26086345

Neurobiological Interactions Between Stress and the Endocannabinoid System.

“Stress affects a constellation of physiological systems in the body and evokes a rapid shift in many neurobehavioral processes.

A growing body of work indicates that the endocannabinoid (eCB) system is an integral regulator of the stress response.

In the current review, we discuss the evidence to date that demonstrates stress-induced regulation of eCB signaling and the consequential role changes in eCB signaling play with respect to many of the effects of stress.

Across a wide array of stress paradigms, studies have generally shown that stress evokes bidirectional changes in the two eCB molecules, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), with stress exposure reducing AEA levels and increasing 2-AG levels.

Additionally, in almost every brain region examined, exposure to chronic stress reliably causes a down-regulation or loss of cannabinoid type 1 (CB1) receptors.

With respect to the functional role of changes in eCB signaling during stress, studies have demonstrated that the decline in AEA appears to contribute to the manifestation of the stress response, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and increases in anxiety behavior, while the increased 2-AG signaling contributes to termination and adaptation of the HPA axis, as well as potentially contributing to changes in pain perception and synaptic plasticity.

More so, translational studies have shown that eCB signaling in humans regulates many of the same domains and appears to be a critical component of stress regulation, and impairments in this system may be involved in the vulnerability to stress-related psychiatric conditions, such as depression and post-traumatic stress disorder.

Collectively, these data create a compelling argument that eCB signaling is an important regulatory system in the brain that largely functions to buffer against many of the effects of stress and that dynamic changes in this system contribute to different aspects of the stress response.”

http://www.ncbi.nlm.nih.gov/pubmed/26068727

Role of the endocannabinoid system in the emotional manifestations of osteoarthritis pain.

“The levels of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol.

In this study, we investigated the role of the endocannabinoid system (ECS) in the emotional and cognitive alterations associated with osteoarthritis pain.

Changes found in these biomarkers of the ECS correlated with pain, affective and cognitive symptoms in these patients.

The ECS plays a crucial role in osteoarthritis and represents an interesting pharmacological target and biomarker of this disease.”

http://www.ncbi.nlm.nih.gov/pubmed/26067584

http://www.thctotalhealthcare.com/category/osteoarthritis/

Full FAAH inhibition combined with partial monoacylglycerol lipase inhibition: Augmented and sustained antinociceptive effects with negligible cannabimimetic side effects in mice.

“Inhibition of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MAGL), the primary hydrolytic enzymes for the respective endocannabinoids, N-arachidonoylethanolamine (AEA) and 2-arachidonylglycerol (2-AG), produces antinociception, but with minimal cannabimimetic side effects.

Although selective inhibitors of either enzyme often show partial efficacy in various nociceptive models, their combined blockade elicits augmented antinociceptive effects, but side effects emerge. Moreover, complete and prolonged MAGL blockade leads to CB1 receptor functional tolerance, which represents another challenge in this potential therapeutic strategy.

Therefore, the present study tested whether full FAAH inhibition, combined with partial MAGL inhibition, would produce sustained antinociceptive effects with minimal cannabimimetic side effects…

Thus, full FAAH inhibition combined with partial MAGL inhibition reduces neuropathic and inflammatory pain states, with minimal cannabimimetic effects.”

Downstream effects of endocannabinoid on blood cells: implications for health and disease.

“Endocannabinoids (eCBs), among which N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) are the most biologically active members, are polyunsaturated lipids able to bind cannabinoid, vanilloid and peroxisome proliferator-activated receptors. Depending on the target engaged, these bioactive mediators can regulate different signalling pathways, at both central and peripheral levels.

The biological action of eCBs is tightly controlled by a plethora of metabolic enzymes which, together with the molecular targets of these substances, form the so-called “endocannabinoid system”.

The ability of eCBs to control manifold peripheral functions has received a great deal of attention, especially in the light of their widespread distribution in the body.

In particular, eCBs are important regulators in blood, where they modulate haematopoiesis, platelet aggregation and apoptosis, as well as chemokine release and migration of immunocompetent cells.

Here, we shall review the current knowledge on the pathophysiological roles of eCBs in blood. We shall also discuss the involvement of eCBs in those disorders affecting the haematological system, including cancer and inflammation.

Knowledge gained to date underlines a fundamental role of the eCB system in blood, thus suggesting that it may represent a therapeutic promise for a broad range of diseases involving impaired hematopoietic cell functions.”

http://www.ncbi.nlm.nih.gov/pubmed/25957591

Endocannabinoids regulate the activity of astrocytic hemichannels and the microglial response against an injury: In vivo studies.

“Anandamide (AEA) is an endocannabinoid (EC) that modulates multiple functions in the CNS and that is released in areas of injury, exerting putative neuroprotective actions.

In the present study, we have used intravital microscopy to analyze the role of the EC system in the glial response against an acute insult…

In summary, these findings demonstrate that AEA modifies glial functions by promoting an enhanced pro-inflammatory glial response in the brain.”

http://www.ncbi.nlm.nih.gov/pubmed/25917763

Distinct roles of the endocannabinoids anandamide and 2-arachidonoylglycerol in social behavior and emotionality at different developmental ages in rats.

“To date, our understanding of the relative contribution and potential overlapping roles of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in the regulation of brain function and behavior is still limited. To address this issue, we investigated the effects of systemic administration of JZL195, that simultaneously increases AEA and 2-AG signaling by inhibiting their hydrolysis, in the regulation of socio-emotional behavior in adolescent and adult rats.

These findings provide the first evidence for a role of 2-AG in social behavior, highlight the different contributions of AEA and 2-AG in the modulation of emotionality at different developmental ages and suggest that pharmacological inhibition of AEA and 2-AG hydrolysis is a useful approach to investigate the role of these endocannabinoids in neurobehavioral processes.”

http://www.ncbi.nlm.nih.gov/pubmed/25914159

Inhibition of FAAH reduces nitroglycerin-induced migraine-like pain and trigeminal neuronal hyperactivity in mice.

“There is evidence to suggest that a dysregulation of endocannabinoid signaling may contribute to the etiology and pathophysiology of migraine.

Thus, patients suffering from chronic migraine or medication overuse headache showed alterations in the activity of the arachidonoylethanolamide (AEA) degrading enzyme fatty acid amide hydrolase (FAAH) and a specific AEA membrane transporter, alongside with changes in AEA levels.

The precise role of different endocannabinoid system components is, however, not clear. We have therefore investigated mice with a genetic deletion of the two main cannabinoid receptors CB1 and CB2, or the main endocannabinoid degrading enzymes, FAAH and monoacylglycerol lipase (MAGL), which degrades 2-arachidonoylglycerol (2-AG), in a nitroglycerine-induced animal model of migraine.

The effects of the genetic deletion of pharmacological blockade of FAAH are mediated by CB1 receptors, because they were completely disrupted with the CB1 antagonist rimonabant.

These results identify FAAH as a target for migraine pharmacotherapy.”

http://www.ncbi.nlm.nih.gov/pubmed/25910421

http://www.thctotalhealthcare.com/category/headachemigraine/

A Basal Tone of 2-Arachidonoylglycerol Contributes to Early Oligodendrocyte Progenitor Proliferation by Activating Phosphatidylinositol 3-Kinase (PI3K)/AKT and the Mammalian Target of Rapamycin (MTOR) Pathways.

“A basal tone of the endocannabinoid 2-arachidonoylglycerol (2-AG) enhances late oligodendrocyte progenitor cell (OPC) differentiation. Here, we investigated whether endogenous 2-AG may also promote OPC proliferation in earlier stages…

Our data suggest that proliferation of early OPCs stimulated by PDGF-AA and bFGF depends on the tonic activation of cannabinoid receptors by endogenous 2-AG and provide further evidence on the role of endocannabinoids in oligodendrocyte development, being important for the maintenance and self-renewal of the OPCs.

The results highlight the therapeutic potential of the endocannabinoid signaling in the emerging field of brain repair.”

http://www.ncbi.nlm.nih.gov/pubmed/25900077

Regulation of inflammation by cannabinoids, the endocannabinoids 2-arachidonoyl-glycerol and arachidonoyl-ethanolamide, and their metabolites.

“2-Arachidonoyl-glycerol (2-AG) and arachidonyl-ethanolamide (AEA) are endocannabinoids that have been implicated in many physiologic disorders, including obesity, metabolic syndromes, hepatic diseases, pain, neurologic disorders, and inflammation.

Their immunomodulatory effects are numerous and are not always mediated by cannabinoid receptors, reflecting the presence of an arachidonic acid (AA) molecule in their structure, the latter being the precursor of numerous bioactive lipids that are pro- or anti-inflammatory.

2-AG and AEA can thus serve as a source of AA but can also be metabolized by most eicosanoid biosynthetic enzymes, yielding additional lipids.

In this regard, enhancing endocannabinoid levels by using endocannabinoid hydrolysis inhibitors is likely to augment the levels of these lipids that could regulate inflammatory cell functions.

This review summarizes the metabolic pathways involved in the biosynthesis and metabolism of AEA and 2-AG, as well as the biologic effects of the 2-AG and AEA lipidomes in the regulation of inflammation.”

http://www.ncbi.nlm.nih.gov/pubmed/25877930