Author Archives: David Worrell

Harnessing the Endocannabinoid 2-Arachidonoylglycerol to Lower Intraocular Pressure in a Murine Model.

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“Cannabinoids, such as Δ9-THC, act through an endogenous signaling system in the vertebrate eye that reduces IOP via CB1 receptors.

Endogenous cannabinoid (eCB) ligand, 2-arachidonoyl glycerol (2-AG), likewise activates CB1 and is metabolized by monoacylglycerol lipase (MAGL). We investigated ocular 2-AG and its regulation by MAGL and the therapeutic potential of harnessing eCBs to lower IOP.

Our data confirm a central role for MAGL in metabolism of ocular 2-AG and related lipid species, and that endogenous 2-AG can be harnessed to reduce IOP. The MAGL blocker KML29 has promise as a therapeutic agent, while JZL184 may have difficulty crossing the cornea.

These data, combined with the relative specificity of MAGL for ocular monoacylglycerols and the lack of desensitization in MAGL-/- mice, suggest that the development of an optimized MAGL blocker offers therapeutic potential for treatment of elevated IOP.”

http://www.ncbi.nlm.nih.gov/pubmed/27333182

Fatty Acid Binding Protein-1 (FABP1) and the Human FABP1 T94A Variant: Roles in the Endocannabinoid System and Dyslipidemias.

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“The first discovered member of the mammalian FABP family, liver fatty acid binding protein (FABP1, L-FABP), occurs at high cytosolic concentration in liver, intestine, and in the case of humans also in kidney. While the rat FABP1 is well studied, the extent these findings translate to human FABP1 is not clear-especially in view of recent studies showing that endocannabinoids and cannabinoids represent novel rat FABP1 ligands and FABP1 gene ablation impacts the hepatic endocannabinoid system, known to be involved in non-alcoholic fatty liver (NAFLD) development. Although not detectable in brain, FABP1 ablation nevertheless also impacts brain endocannabinoids. Despite overall tertiary structure similarity, human FABP1 differs significantly from rat FABP1 in secondary structure, much larger ligand binding cavity, and affinities/specificities for some ligands. Moreover, while both mouse and human FABP1 mediate ligand induction of peroxisome proliferator activated receptor-α (PPARα), they differ markedly in pattern of genes induced. This is critically important because a highly prevalent human single nucleotide polymorphism (SNP) (26-38 % minor allele frequency and 8.3 ± 1.9 % homozygous) results in a FABP1 T94A substitution that further accentuates these species differences. The human FABP1 T94A variant is associated with altered body mass index (BMI), clinical dyslipidemias (elevated plasma triglycerides and LDL cholesterol), atherothrombotic cerebral infarction, and non-alcoholic fatty liver disease (NAFLD). Resolving human FABP1 and the T94A variant’s impact on the endocannabinoid and cannabinoid system is an exciting challenge due to the importance of this system in hepatic lipid accumulation as well as behavior, pain, inflammation, and satiety.”

http://www.ncbi.nlm.nih.gov/pubmed/27117865

Fabp-1 gene ablation impacts brain endocannabinoid system in male mice.

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“Liver fatty acid binding protein (FABP1, L-FABP) has high affinity for and enhances uptake of arachidonic acid (ARA, C20:4, n-6) which, when esterified to phospholipids, is the requisite precursor for synthesis of endocannabinoids (EC) such as arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG). The brain derives most of its ARA from plasma, taking up ARA and transporting it intracellularly via cytosolic fatty acid binding proteins (FABPs 3,5, and 7) localized within the brain. In contrast, the much more prevalent cytosolic FABP1 is not detectable in the brain but is instead highly expressed in the liver. Therefore, the possibility that FABP1 outside the central nervous system may regulate brain AEA and 2-AG was examined in wild-type (WT) and FABP1 null (LKO) male mice. LKO increased brain levels of AA-containing EC (AEA, 2-AG), correlating with increased free and total ARA in brain and serum. LKO also increased brain levels of non-ARA that contain potentiating endocannabinoids (EC*) such as OEA, PEA, 2-OG, and 2-PG. Concomitantly, LKO decreased serum total ARA-containing EC, but not non-ARA endocannabinoids. LKO did not elicit these changes in the brain EC and EC* due to compensatory upregulation of brain protein levels of enzymes in EC synthesis (NAPEPLD, DAGLα) or cytosolic EC chaperone proteins (FABPs 3, 5, 7, SCP-2, HSP70), or cannabinoid receptors (CB1, TRVP1). These data show for the first time that the non-CNS fatty acid binding protein FABP1 markedly affected brain levels of both ARA-containing endocannabinoids (AEA, 2-AG) as well as their non-ARA potentiating endocannabinoids.”

http://www.ncbi.nlm.nih.gov/pubmed/27167970

FABP1 in wonderland.

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“Cannabinoid receptors hold a core position in the brain and control memory, cognition, movement, and pain sensitivity. sn-2 arachidonoylglycerol (2-AG) activates neuronal cannabinoid receptors as a full agonist. The brain may rely on circulating arachidonic acid to synthesize endogenous cannabinoids. This Editorial highlights a study by Martin and coworkers in the current issue of the Journal of Neurochemistry in which the authors describe, for the first time, that liver acts as a pool of arachidonic acid that under certain conditions feeds the brain to produce endocannabinoids. Therapeutics affecting liver FABP1 levels should take into account that FABP1 represents a fatty acid reservoirs for the brain. Read the highlighted article “FABP-1 gene ablation impacts brain endocannabinoid system in male mice”” http://www.ncbi.nlm.nih.gov/pubmed/27329821

Activation of cannabinoid CB1 receptors suppresses the ROS-induced hypersensitivity of rat vagal lung C-fiber afferents.

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“Reactive oxygen species (ROS), including H2O2, have been shown to induce hypersensitivity of vagal lung C-fibers (VLCFs) mainly through receptor potential ankyrin 1 (TRPA1) and P2X receptors.

Cannabinoids (CBs) exert antinociceptive effects by binding to specific CB receptors, designated CB1 and CB2 (type 2) for type 1 and type 2, respectively.

We investigated whether activation of CB receptors can suppress ROS-mediated VLCF hypersensitivity and, if so, what type(s) of CB receptors are involved.

:Our results suggest that activation of CB1 receptors may suppress the ROS-mediated VLCF hypersensitivity through a mechanism that is at least partly distinct from the function of TRPA1 and P2X receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27328978

Basolateral amygdala CB1 cannabinoid receptors are involved in cross state-dependent memory retrieval between morphine and ethanol.

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“Ethanol and morphine are largely co-abused and affect memory formation.

The present study intended to investigate the involvement of cannabinoid CB1 receptors of the basolateral amygdala (BLA) in cross state-dependent memory retrieval between morphine and ethanol.

Taken together, it can be concluded that morphine and ethanol can induce state-dependent memory retrieval.

In addition, the BLA endocannabinoid system mediates via CB1 receptors the functional interaction of morphine and ethanol state-dependent memory retrieval which may depend on the rewarding effects of the drugs.”

http://www.ncbi.nlm.nih.gov/pubmed/27327764

The multiplicity of spinal AA-5-HT anti-nociceptive action in a rat model of neuropathic pain.

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“There is considerable evidence to support the role of anandamide (AEA), an endogenous ligand of cannabinoid receptors, in neuropathic pain modulation. AEA also produces effects mediated by other biological targets, of which the transient receptor potential vanilloid type 1 (TRPV1) has been the most investigated. Both, inhibition of AEA breakdown by fatty acid amide hydrolase (FAAH) and blockage of TRPV1 have been shown to produce anti-nociceptive effects.

Recent research suggests the usefulness of dual-action compounds, which may afford greater anti-allodynic efficacy. Therefore, in the present study, we examined the effect of N-arachidonoyl-serotonin (AA-5-HT), a blocker of FAAH and TRPV1, in a rat model of neuropathic pain after intrathecal administration.

We found that treatment with AA-5-HT increased the pain threshold to mechanical and thermal stimuli, with highest effect at the dose of 500nM, which was most strongly attenuated by AM-630, CB2 antagonist, administration. The single action blockers PF-3845 (1000nM, for FAAH) and I-RTX (1nM, for TRPV1) showed lower efficacy than AA-5-HT. Moreover AA-5-HT (500nM) elevated AEA and palmitoylethanolamide (PEA) levels.

Among the possible targets of these mediators, only the mRNA levels of CB2, GPR18 and GPR55, which are believed to be novel cannabinoid receptors, were upregulated in the spinal cord and/or DRG of CCI rats. It was previously reported that AA-5-HT acts in CB1 and TRPV1-dependent manner after systemic administration, but here for the first time we show that AA-5-HT action at the spinal level involves CB2, with potential contributions from GRP18 and/or GPR55 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27326920

The cannabinoid WIN 55,212-2 prevents neuroendocrine differentiation of LNCaP prostate cancer cells.

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“Neuroendocrine (NE) differentiation represents a common feature of prostate cancer and is associated with accelerated disease progression and poor clinical outcome. Nowadays, there is no treatment for this aggressive form of prostate cancer.

The aim of this study was to determine the influence of the cannabinoid WIN 55,212-2 (WIN, a non-selective cannabinoid CB1 and CB2 receptor agonist) on the NE differentiation of prostate cancer cells.

Taken together, we demonstrate that PI3K/Akt/AMPK might be an important axis modulating NE differentiation of prostate cancer that is blocked by the cannabinoid WIN, pointing to a therapeutic potential of cannabinoids against NE prostate cancer.”

http://www.ncbi.nlm.nih.gov/pubmed/27324222

Susceptibility of Naegleria fowleri to delta 9-tetrahydrocannabinol.

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Logo of aac“Growth of the pathogenic amoeboflagellate Naegleria fowleri is inhibited by delta 9-tetrahydrocannabinol (delta 9-THC).

delta 9-THC is amoebostatic at 5 to 50 micrograms/ml. delta 9-THC prevents enflagellation and encystment, but does not impair amoeboid movement. Calf serum at 10 and 20% (vol/vol) reduces the antiamoeba activity of delta 9-THC.

Only 1-methoxy delta 8-tetrahydrocannabinol, of 17 cannabinoids tested, failed to inhibit growth of N. fowleri.

Antinaeglerial activity was not markedly altered by opening the pyran ring, by converting the cyclohexyl ring to an aromatic ring, or by reversing the hydroxyl and pentyl groups on the benzene ring.

delta 9-THC prevented the cytopathic effect of N. fowleri on African green monkey (Vero) cells and human epithelioma (HEp-2) cells in culture. delta 9-THC afforded modest protection to mice infected with N. fowleri.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC352928/

https://aac.asm.org/content/16/5/674?maxtoshow=&hits=80&RESULTFORMAT=&fulltext=ma

“Naegleria fowleri, colloquially known as the “brain-eating amoeba“”  https://en.wikipedia.org/wiki/Naegleria_fowleri

Identification of Psychoactive Degradants of Cannabidiol in Simulated Gastric and Physiological Fluid

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“The flowering plants of the genus Cannabis, which mainly comprises the sativa and indica species, have been recognized for medical treatment for millennia.

Although Cannabis contains nearly 500 compounds from 18 chemical classes, its physiological effects derive mainly from a family of naturally occurring compounds known as plant cannabinoids or phytocannabinoids. Of the more than 100 phytocannabinoids that have been identified in Cannabis, among the most important and widely studied are its main psychoactive constituent, Δ9-tetrahydrocannabinol (Δ9-THC), and the most important nonpsychoactive component, cannabidiol (CBD). Other biologically active phytocannabinoids that have been isolated in Cannabis include Δ8-THC, cannabinol, Δ9-tetrahydrocannabivarin, and cannabidivarin.

In recent research, orally administered cannabidiol (CBD) showed a relatively high incidence of somnolence in a pediatric population. Previous work has suggested that when CBD is exposed to an acidic environment, it degrades to Δ9-tetrahydrocannabinol (THC) and other psychoactive cannabinoids. To gain a better understanding of quantitative exposure, we completed an in vitro study by evaluating the formation of psychoactive cannabinoids when CBD is exposed to simulated gastric fluid (SGF).

SGF converts CBD into the psychoactive components Δ9-THC and Δ8-THC. The first-order kinetics observed in this study allowed estimated levels to be calculated and indicated that the acidic environment during normal gastrointestinal transit can expose orally CBD-treated patients to levels of THC and other psychoactive cannabinoids that may exceed the threshold for a physiological response. Delivery methods that decrease the potential for formation of psychoactive cannabinoids should be explored.

Despite persistent challenges with dosing and administration, CBD-based therapies have a good safety profile and a potential for efficacy in the treatment of a variety of medical conditions. The rapidly evolving sciences of drug delivery and cannabinoid pharmacology may soon lead to breakthroughs that will improve access to the benefits of this pharmacological class of agents. In addition, current technologies, such as transdermal-based therapy, may be able to eliminate the potential for psychotropic effects due to this acid-catalyzed cyclization by delivering CBD through the skin and into the neutral, nonreactive environment of the systemic circulation.”

http://online.liebertpub.com/doi/10.1089/can.2015.0004