Editorial: The CB2 Cannabinoid System: A New Strategy in Neurodegenerative Disorder and Neuroinflammation

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“The cannabinoid receptors subtype 2 (CB2R) are emerging as novel targets for the development of new therapeutic approaches and PET probes useful to early diagnose neuroinflammation as first step in several neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson disease (PD).

This Research Topic is mainly focused on the involvment of CB2R in neurodegenerative disorders and on the usefulness of CB2R ligands in the therapy and early diagnosis of neuroinflammation as onset of neurodegeneration.

In the reviews of Aso and Ferrer and Cassano et al. an interesting and exaustive overview of the endogenous cannabinoid signaling and its role in neuroinflammation and neurogenesis is reported. The potential of CB2R as therapeutic target in AD is argued by several evidences derived by robust experimental models and the effects modulated by CB2R agonists on different pathways involved in the pathogenesis of AD are discussed; indeed, these ligands are able to reduce inflammation, Aβ production and deposition, tau protein hyper-phosphorylation and oxidative stress damage caused by Aβ peptides. CB2R agonists are also able to induce Aβ clearance leading to cognitive improvement in AD models.

In conclusion, considering that neuroinflammation has been widely reported as indicator and modulator of neurodegeneration, the reduction of the neuroinflammatory responses could be considered as a new therapeutic strategy in these diseases. Moreover, the selective CB2R overexpression on the activated-microglial cells provides also a highly specialized target useful to an early diagnosis of the neurodegenerative diseases.”

http://journal.frontiersin.org/article/10.3389/fnins.2017.00196/full]]>

Anandamide and 2-AG Are Endogenously Present within the Laterodorsal Tegmental Nucleus: Functional Implications for a role of eCBs in arousal.

“Previously, we presented electrophysiological evidence for presence in mice brain slices of functional cannabinoid type I receptors (CB1Rs) within the laterodorsal tegmentum (LDT), a brain stem nucleus critical in control of arousal and rapid eye movement (REM) sleep. Further, using pharmacological agents, we provided data suggestive of the endogenous presence of cannabinoids (CBs) acting at LDT CB1Rs. However, in those studies, we were unable to identify the type(s) of CB ligands endogenously present in the LDT, and this information has not been provided elsewhere. Accordingly, we used the highly-sensitive liquid chromatography/mass spectrometry (LC-MS) method to determine whether N-arachidonoylethanolamide (Anandamide or AEA) and 2-arachidonyl glycerol (2-AG), which are both endogenous CB ligands acting at CB1Rs, are present in the LDT. Mice brain tissue samples of the LDT were assayed using ion trap LC-MS in selected ion monitoring mode. Chromatographic analysis and product-ion MS scans identified presence of the CBs, AEA and 2-AG, from LDT mouse tissue. Data using the LC-MS method show that AEA and 2-AG are endogenously present within the LDT and when coupled with our electrophysiological findings, lead to the suggestion that AEA and 2-AG act at electropharmacologically-demonstrated CB1Rs in this nucleus. Accordingly, AEA and 2-AG likely play a role in processes governed by the LDT, including control of states of cortical gamma band activity seen in alert, aroused states, as well as cortical and motor activity characteristic of REM sleep.” https://www.ncbi.nlm.nih.gov/pubmed/28404451]]>

Enhancement of Anandamide-Mediated Endocannabinoid Signaling Corrects Autism-Related Social Impairment

Mary Ann Liebert, Inc. publishers We recently uncovered a signaling mechanism by which the endocannabinoid anandamide mediates the action of oxytocin, a neuropeptide that is crucial for social behavior, to control social reward. Oxytocin signaling has been implicated in autism spectrum disorder (ASD), and social reward is a key aspect of social functioning that is thought to be disrupted in ASD. Therefore, as a proof of principle for the core component of ASD—social impairment—we tested an endocannabinoid-enhancing compound on two widely studied mouse models of ASD, the BTBR and fmr1−/− (model of Fragile X Syndrome). Remarkably, we found that FAAH blockade completely reversed the social impairment in both mouse models. CB1 receptor blockade prevented the prosocial action of FAAH inhibition in BTBR mice. The results suggest that increasing anandamide activity at CB1 receptors improves ASD-related social impairment and identify FAAH as a novel therapeutic target for ASD.
In conclusion, the present study provides new insights into the role of endocannabinoid signaling in social behavior and validates FAAH as a novel therapeutic target for the social impairment of ASD.”
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