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Systematic Affinity Purification Coupled to Mass Spectrometry Identified p62 as Part of the Cannabinoid Receptor CB2 Interactome.

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Image result for frontiers in molecular neuroscience“The endocannabinoid system (ECS) consists particularly of cannabinoid receptors 1 and 2 (CB1 and CB2), their endogenous ligands, and enzymes that synthesize and degrade their ligands. It acts in a variety of organs and disease states ranging from cancer progression over neuropathic pain to neurodegeneration. Protein components engaged in the signaling, trafficking, and homeostasis machinery of the G-protein coupled CB2, are however largely unknown. It is therefore important to identify further interaction partners to better understand CB2 receptor functions in physiology and pathophysiology. For this purpose, we used an affinity purification and mass spectrometry-based proteomics approach of Strep-HA-CB2 receptor in HEK293 cells. After subtraction of background interactions and protein frequency library assessment we could identify 83 proteins that were classified by the identification of minimally 2 unique peptides as highly probable interactors. A functional protein association network analysis obtained an interaction network with a significant enrichment of proteins functionally involved in protein metabolic process, in endoplasmic reticulum, response to stress but also in lipid metabolism and membrane organization. The network especially contains proteins involved in biosynthesis and trafficking like calnexin, Sec61A, tubulin chains TUBA1C and TUBB2B, TMED2, and TMED10. Six proteins that were only expressed in stable CB2 expressing cells were DHC24, DHRS7, GGT7, HECD3, KIAA2013, and PLS1. To exemplify the validity of our approach, we chose a candidate having a relatively low number of edges in the network to increase the likelihood of a direct protein interaction with CB2 and focused on the scaffold/phagosomal protein p62/SQSTM1. Indeed, we independently confirmed the interaction by co-immunoprecipitation and immunocytochemical colocalization studies. 3D reconstruction of confocal images furthermore showed CB2 localization in close proximity to p62 positive vesicles at the cell membrane. In summary, we provide a comprehensive repository of the CB2 interactome in HEK293 cells identified by a systematic unbiased approach, which can be used in future experiments to decipher the signaling and trafficking complex of this cannabinoid receptor. Future studies will have to analyze the exact mechanism of the p62-CB2 interaction as well as its putative role in disease pathophysiology.”

https://www.ncbi.nlm.nih.gov/pubmed/31616248

https://www.frontiersin.org/articles/10.3389/fnmol.2019.00224/full

Cannabinoid Receptor Interacting Protein 1a (CRIP1a): Function and Structure.

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molecules-logo“Cannabinoid receptor interacting protein 1a (CRIP1a) is an important CB1 cannabinoid receptor-associated protein, first identified from a yeast two-hybrid screen to modulate CB1-mediated N-type Ca2+ currents. In this paper we review studies of CRIP1a function and structure based upon in vitro experiments and computational chemistry, which elucidate the specific mechanisms for the interaction of CRIP1a with CB1 receptors. N18TG2 neuronal cells overexpressing or silencing CRIP1a highlighted the ability of CRIP1 to regulate cyclic adenosine 3′,5’monophosphate (cAMP) production and extracellular signal-regulated kinase (ERK1/2) phosphorylation. These studies indicated that CRIP1a attenuates the G protein signaling cascade through modulating which Gi/o subtypes interact with the CB1 receptor. CRIP1a also attenuates CB1 receptor internalization via β-arrestin, suggesting that CRIP1a competes for β-arrestin binding to the CB1 receptor. Predictions of CRIP1a secondary structure suggest that residues 34-110 are minimally necessary for association with key amino acids within the distal C-terminus of the CB1 receptor, as well as the mGlu8a metabotropic glutamate receptor. These interactions are disrupted through phosphorylation of serines and threonines in these regions. Through investigations of the function and structure of CRIP1a, new pharmacotherapies based upon the CRIP-CB1 receptor interaction can be designed to treat diseases such as epilepsy, motor dysfunctions and schizophrenia.”

https://www.ncbi.nlm.nih.gov/pubmed/31614728

https://www.mdpi.com/1420-3049/24/20/3672

CLG from Hemp Seed Inhibits LPS-Stimulated Neuroinflammation in BV2 Microglia by Regulating NF-κB and Nrf-2 Pathways.

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Go to Volume 4, Issue 15“The healthy benefits of hemp (Cannabis sativa L.) seed have often been attributed to its oils and proteins.

Recent studies reveal that hemp seed phenylpropionamides could also show various bioactivities. Continuation of our study on hemp seed provided a phenylpropionamide, coumaroylaminobutanol glucopyranoside (CLG). This work investigated the neuroprotective effect of CLG and its underlying mechanism using lipopolysaccharide-induced BV2 microglia.

Our study demonstrated that CLG increased adenosine monophosphate-activated protein kinase (AMPK) expression, suppressed the nuclear factor-kappa B (NF-κB) signaling pathway by inhibiting the phosphorylation of IκBα and NF-κB p65 and decreased proinflammatory cytokine levels in a concentration-dependent manner. Furthermore, CLG reduced the production of cellular reactive oxygen species and stimulated the nuclear factor erythroid 2-related factor 2 (Nrf-2) signaling pathway.

Collectively, these results suggested that CLG effectively and simultaneously inhibited inflammatory responses and oxidative stress through the NF-κB and Nrf-2 signaling pathways. AMPK was also involved in the anti-inflammatory effect of CLG. This study provides new insights into the diverse bioactive constituents of hemp seed.”

https://www.ncbi.nlm.nih.gov/pubmed/31616830

“Hemp (Cannabis sativa L.) seed has been used as food and traditional medicine for centuries. Our findings contribute to the knowledge of diverse bioactive compounds from hemp seed and the potential of hemp seed in the treatment of microglia-related neuroinflammatory diseases.”

https://pubs.acs.org/doi/10.1021/acsomega.9b02168

How does cannabidiol (CBD) influence the acute effects of delta-9-tetrahydrocannabinol (THC) in humans? A systematic review.

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Neuroscience & Biobehavioral Reviews“The recent liberalisation of cannabis regulation has increased public and scientific debate about its potential benefits and risks. A key focus has been the extent to which cannabidiol (CBD) might influence the acute effects of delta-9-tetrahydrocannabinol (THC), but this has never been reviewed systematically. In this systematic review of how CBD influences the acute effects of THC we identified 16 studies involving 466 participants. Ten studies were judged at low risk of bias. The findings were mixed, although CBD was found to reduce the effects of THC in several studies. Some studies found that CBD reduced intense experiences of anxiety or psychosis-like effects of THC and blunted some of the impairments on emotion and reward processing. However, CBD did not consistently influence the effects of THC across all studies and outcomes. There was considerable heterogeneity in dose, route of administration and THC:CBD ratio across studies and no clear dose-response profile emerged. Although findings were mixed, this review suggests that CBD may interact with some acute effects of THC.”

https://www.ncbi.nlm.nih.gov/pubmed/31580839

“CBD influenced the effects of THC in some but not all studies. Several studies found that CBD reduced the acute effects of THC. CBD may reduce intense experiences of anxiety or psychosis-like effects of THC. CBD may blunt effects of THC on emotion and reward processing. CBD did not alter subjective intoxication or psychomotor effects of THC. CBD may influence the benefits and harms of cannabis”

https://www.sciencedirect.com/science/article/pii/S0149763419305615?via%3Dihub

Beyond THC and Endocannabinoids.

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Image result for AR Annual Reviews“Research in the cannabinoid field, namely on phytocannabinoids, the endogenous cannabinoids anandamide and 2-arachidonoyl glycerol and their metabolizing and synthetic enzymes, the cannabinoid receptors, and anandamide-like cannabinoid compounds, has expanded tremendously over the last few years. Numerous endocannabinoid-like compounds have been discovered. The Cannabis plant constituent cannabidiol (CBD) was found to exert beneficial effects in many preclinical disease models ranging from epilepsy, cardiovascular disease, inflammation, and autoimmunity to neurodegenerative and kidney diseases and cancer. CBD was recently approved in the United States for the treatment of rare forms of childhood epilepsy. This has triggered the development of many CBD-based products for human use, often with overstated claims regarding their therapeutic effects. In this article, the recently published research on the chemistry and biological effects of plant cannabinoids (specifically CBD), endocannabinoids, certain long-chain fatty acid amides, and the variety of relevant receptors is critically reviewed. ”

https://www.ncbi.nlm.nih.gov/pubmed/31580774

https://www.annualreviews.org/doi/10.1146/annurev-pharmtox-010818-021441

Neuroprotective protein hydrolysates from hemp (Cannabis sativa L.) seeds.

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 “Hemp (Cannabis sativa L.) seeds are well known for their potential use as a source of nutrients, fiber, and bioactive compounds.

A hemp protein isolate, prepared from defatted hemp flour, was hydrolyzed by alcalase and flavourzyme under specific conditions.

The resulting hydrolysates were evaluated for the selection of potentially bioactive hemp protein hydrolysates (HPHs) owing to their DPPH scavenging and ferric reducing antioxidant power activity. In vitro cell-free experiments led to the identification of two bioactive HPHs, HPH20A and HPH60A + 15AF, which were used at 50 and 100 μg mL-1 on BV-2 microglial cells in order to evaluate the anti-neuroinflammatory activities.

Our results showed that HPH20A and HPH60A + 15AF down-regulated TNF-α, IL-1β, and IL-6 mRNA transcriptional levels in LPS-stimulated BV-2 microglial cells. In addition, HPH20A and HPH60A + 15AF up-regulated the gene expression of anti-inflammatory cytokine IL-10.

This study suggests for the first time that HPHs may improve the neuroinflammatory and inflammatory states, supporting the nutraceutical value of hemp seeds.”

https://www.ncbi.nlm.nih.gov/pubmed/31576391

https://pubs.rsc.org/en/content/articlelanding/2019/FO/C9FO01904A#!divAbstract

Absence of Entourage: Terpenoids Commonly Found in Cannabis sativa Do Not Modulate the Functional Activity of Δ9-THC at Human CB1 and CB2 Receptors.

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 View details for Cannabis and Cannabinoid Research cover image“Compounds present in Cannabis sativa such as phytocannabinoids and terpenoids may act in concert to elicit therapeutic effects. Cannabinoids such as Δ9-tetrahydrocannabinol (Δ9-THC) directly activate cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2); however, it is not known if terpenoids present in Cannabis also affect cannabinoid receptor signaling. Therefore, we examined six common terpenoids alone, and in combination with cannabinoid receptor agonists, on CB1 and CB2 signaling in vitro.

Results: α-Pinene, β-pinene, β-caryophyllene, linalool, limonene, and β-myrcene (up to 30-100 μM) did not change membrane potential in AtT20 cells expressing CB1 or CB2, or affect the response to a maximally effective concentration of the synthetic cannabinoid CP55,940. The presence of individual or a combination of terpenoids did not affect the hyperpolarization produced by Δ9-THC (10 μM): (CB1: control, 59%±7%; with terpenoids (10 μM each) 55%±4%; CB2: Δ9-THC 16%±5%, with terpenoids (10 μM each) 17%±4%). To investigate possible effect on desensitization of CB1 responses, all six terpenoids were added together with Δ9-THC and signaling measured continuously over 30 min. Terpenoids did not affect desensitization, after 30 min the control hyperpolarization recovered by 63%±6% in the presence of the terpenoids recovery was 61%±5%.

Discussion: None of the six of the most common terpenoids in Cannabis directly activated CB1 or CB2, or modulated the signaling of the phytocannabinoid agonist Δ9-THC. These results suggest that if a phytocannabinoid-terpenoid entourage effect exists, it is not at the CB1 or CB2 receptor level. It remains possible that terpenoids activate CB1 and CB2 signaling pathways that do not involve potassium channels; however, it seems more likely that they may act at different molecular target(s) in the neuronal circuits important for the behavioral effect of Cannabis.”

https://www.ncbi.nlm.nih.gov/pubmed/31559333

https://www.liebertpub.com/doi/10.1089/can.2019.0016

“Terpenoids and Phytocannabinoids Co-Produced in Cannabis Sativa Strains Show Specific Interaction for Cell Cytotoxic Activity. We found that in “high THC” or “high CBD” strains, phytocannabinoids are produced alongside certain sets of terpenoids. Only co-related terpenoids enhanced the cytotoxic activity of phytocannabinoids on MDA-MB-231 and HCT-116 cell lines. This was found to be most effective in natural ratios found in extracts of cannabis inflorescence.”  https://www.ncbi.nlm.nih.gov/pubmed/31438532

Human leukocytes differentially express endocannabinoid-glycerol lipases and hydrolyze 2-arachidonoyl-glycerol and its metabolites from the 15-lipoxygenase and cyclooxygenase pathways.

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Publication cover image“2-Arachidonoyl-glycerol (2-AG) is an endocannabinoid with anti-inflammatory properties.

Blocking 2-AG hydrolysis to enhance CB2 signaling has proven effective in mouse models of inflammation. However, the expression of 2-AG lipases has never been thoroughly investigated in human leukocytes.

Herein, we investigated the expression of seven 2-AG hydrolases by human blood leukocytes and alveolar macrophages (AMs) and found the following protein expression pattern: monoacylglycerol (MAG lipase; eosinophils, AMs, monocytes), carboxylesterase (CES1; monocytes, AMs), palmitoyl-protein thioesterase (PPT1; AMs), α/β-hydrolase domain (ABHD6; mainly AMs), ABHD12 (all), ABHD16A (all), and LYPLA2 (lysophospholipase 2; monocytes, lymphocytes, AMs).

Altogether, our results indicate that human leukocytes are experts at hydrolyzing 2-AG and its metabolites via multiple lipases and probably via a yet-to-be characterized 52 kDa hydrolase. Blocking 2-AG hydrolysis in humans will likely abrogate the ability of human leukocytes to degrade 2-AG and its metabolites and increase their anti-inflammatory effects in vivo.”

https://www.ncbi.nlm.nih.gov/pubmed/31556464

https://jlb.onlinelibrary.wiley.com/doi/abs/10.1002/JLB.3A0919-049RRR

Opposed Cannabinoid 1 receptor (CB1R) expression in the prefrontal cortex vs. nucleus accumbens is associated with alcohol consumption in male rats.

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Brain Research“Abusive alcohol consumption is a health problem, worldwide.

There is extensive literature indicating that cannabinoid 1 receptor (CB1R) plays a crucial role in mediating alcohol’s reward effects.

Maternal care deprivation (MCD) is a reliable rodent model of early life stress that leads to high levels of anxiety and alterations in motivation, which may increase vulnerability to alcohol consumption.

The present study researched whether anxiety-like behaviors and the level of motivation for a natural reward, and CB1R expression in the prefrontal cortex (PFC) and nucleus accumbens (NAcc) can predict alcohol consumption in non-MCD and MCD male rats.

Results indicate that MCD increases anxiety-like behaviors, i.e., reduces time in open arms in the elevated plus maze and increases alcohol intake. In turn, the motivation for a palatable reward, i.e., a chocolate flavored pellet, was not affected by MCD.

MCD reduces CB1R expression in the PFC and increases it in the NAcc. Hence, both higher anxiety-like behaviors and higher CB1R expression in the NAcc and lower CB1R expression in the PFC are associated with higher alcohol intake.

These results suggest that early life adverse experiences induce a reprogramming of the brain’s endocannabinoid system that very likely contributes to making the brain vulnerable to develop alcohol abuse and dependence.”

https://www.ncbi.nlm.nih.gov/pubmed/31568767

https://www.sciencedirect.com/science/article/abs/pii/S0006899319305396?via%3Dihub

Molecular mechanism of TRPV2 channel modulation by cannabidiol.

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eLife logo

“Transient receptor potential vanilloid 2 (TRPV2) plays a critical role in neuronal development, cardiac function, immunity, and cancer.

Cannabidiol (CBD), the non-psychotropic therapeutically active ingredient of Cannabis sativa, is an activator of TRPV2 and also modulates other transient receptor potential (TRP) channels.

We show that CBD interacts with TRPV2 through a hydrophobic pocket located between S5 and S6 helices of adjacent subunits, which differs from known ligand and lipid binding sites in other TRP channels. CBD-bound TRPV2 structures revealed that the S4-S5 linker plays a critical role in channel gating upon CBD binding. Additionally, nanodiscs permitted us to visualize two distinct TRPV2 apo states in a lipid environment.

Together these results provide a foundation to further understand TRPV channel gating, their divergent physiological functions, and to accelerate structure-based drug design.”

https://www.ncbi.nlm.nih.gov/pubmed/31566564

https://elifesciences.org/articles/48792