Targeting Cutaneous Cannabinoid Signaling in Inflammation – A “High”-way to Heal?

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“The endocannabinoid system (ECS) is a recently emerging complex regulator of multiple physiological processes. It comprises several endogenous ligands (e.g. N-arachidonoylethanolamine, a.k.a. anandamide [AEA], 2-arachidonoylglycerol [2-AG], palmitoylethanolamide [PEA], etc.), a number of endocannabinoid (eCB)-responsive receptors (e.g. CB1 and CB2, etc.), as well as enzymes and transporters involved in the synthesis and degradation of the eCBs.

Among many other tissues and organs, various members of the ECS were shown to be expressed in the skin as well. Indeed, AEA, 2-AG, CB1 and CB2 together with the major eCB-metabolizing enzymes (e.g. fatty acid amide hydrolase [FAAH], which cleaves AEA to ethanolamine and pro-inflammatory arachidonic acid) were found in various cutaneous cell types. Importantly, the eCB-tone and cannabinoid signaling in general appear to play a key role in regulating several fundamental aspects of cutaneous homeostasis, including proliferation and differentiation of epidermal keratinocytes, hair growth, sebaceous lipid production, melanogenesis, fibroblast activity, etc.

Moreover, appropriate eCB-signaling through CB1 and CB2 receptors was found to be crucially important in keeping cutaneous inflammatory processes under control.

Collectively, these findings (together with many other recently published data) implied keratinocytes to be “non-classical” immune competent cells, playing a central role in initiation and regulation of cutaneous immune processes, and the “c(ut)annabinoid” system is now proven to be one of their master regulators.

Another recently emerging, fascinating possibility to manage cutaneous inflammation through the cannabinoid signaling is the administration of phytocannabinoids (pCB). Cannabis sativa contains over 100 different pCBs, the vast majority of which have no psychotropic activity, and usually possess a “favorable” side-effect profile, which makes these substances particularly interesting drug candidates in treating several inflammation-accompanied diseases.

With respect to the skin, we have recently shown that one of the best studied pCBs, (−)-cannabidiol (CBD), may have great potential in managing acne, an inflammation-accompanied, extremely prevalent cutaneous disease.

Collectively, in light of the above results, both increase/restoration of the homeostatic cutaneous eCB-tone by FAAH-inhibitors and topical administration of non-psychotropic pCBs hold out the promise to exert remarkable anti-inflammatory actions, making them very exciting drug candidates, deserving full clinical exploration as potent, yet safe novel class of anti-inflammatory agents.”

http://www.ebiomedicine.com/article/S2352-3964(17)30003-8/fulltext]]>

Alteration of the endocannabinoid system in mouse brain during prion disease.

“Prion diseases are neurodegenerative disorders characterized by deposition of the pathological prion protein (PrPsc) within the brain of affected humans and animals. Microglial cell activation is a common feature of prion diseases; alterations of various neurotransmitter systems and neurotransmission have been also reported. Owing to its ability to modulate both neuroimmune responses and neurotransmission, it was of interest to study the brain endocannabinoid system in a prion-infected mouse model. The production of the endocannabinoid, 2-arachidonoyglycerol (2-AG), was enhanced 10 weeks post-infection, without alteration of the other endocannabinoid, anandamide. The CB2 receptor expression was up-regulated in brains of prion-infected mice as early as 10 weeks and up to 32 weeks post-infection whereas the mRNAs of other cannabinoid receptors (CBRs) remain unchanged. The observed alterations of the endocannabinoid system were specific for prion infection since no significant changes were observed in the brain of prion-resistant mice, that is, mice devoid of the Prnp gene. Our study highlights important alterations of the endocannabinoid system during early stages of the disease long before the clinical signs of the disease.”  https://www.ncbi.nlm.nih.gov/pubmed/21195746

“Prion diseases are a group of neurodegenerative diseases caused by prions, which are “proteinaceous infectious particles.” Prion diseases are caused by misfolded forms of the prion protein, also known as PrP. These diseases affect a lot of different mammals in addition to humans. The human forms of prion disease are most often the names Creutzfeldt-Jakob disease (CJD), fatal familial insomnia (FFI), Gertsmann-Straussler-Scheinker syndrome (GSS), kuru and variably protease-sensitive prionopathy (VPSPr). All of these diseases are caused by just slightly different versions of the same protein, so we refer to them all as prion diseases.” http://www.prionalliance.org/2013/12/02/what-are-human-prion-diseases/
“Eating meat contaminated with bovine spongiform encephalopathy and its hallmark misshapen proteins, called prions, can cause a fatal and untreatable brain disorder,” http://www.sciencemag.org/news/2016/12/mad-cow-disease-remains-threat-new-blood-tests-could-detect-it
“Prions are terrifying.”
“Marijuana Kills MRSA and Inhibits Prions That Cause Neurodegenerative Disease; Still Recognized by Feds As a Dangerous Drug.” http://www.medicaldaily.com/marijuana-kills-mrsa-and-inhibits-prions-cause-neurodegenerative-disease-still-recognized-feds
 
“Antibacterial cannabinoids from Cannabis sativa: a structure-activity study.” http://www.ncbi.nlm.nih.gov/pubmed/18681481
“Nonpsychoactive Cannabidiol Prevents Prion Accumulation and Protects Neurons against Prion Toxicity. Our results suggest that CBD may protect neurons against the multiple molecular and cellular factors involved in the different steps of the neurodegenerative process, which takes place during prion infection. When combined with its ability to target the brain and its lack of toxic side effects, CBD may represent a promising new anti-prion drug. ” http://www.jneurosci.org/content/27/36/9537.full
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Pharmacology of cannabinoids in the treatment of epilepsy.

“The use of cannabis products in the treatment of epilepsy has long been of interest to researchers and clinicians alike; however, until recently very little published data were available to support its use. This article summarizes the available scientific data of pharmacology from human and animal studies on the major cannabinoids which have been of interest in the treatment of epilepsy, including ∆9-tetrahydrocannabinol (∆9-THC), cannabidiol (CBD), ∆9-tetrahydrocannabivarin (∆9-THCV), cannabidivarin (CBDV), and ∆9-tetrahydrocannabinolic acid (Δ9-THCA). It has long been known that ∆9-THC has partial agonist activity at the endocannabinoid receptors CB1 and CB2, though it also binds to other targets which may modulate neuronal excitability and neuroinflammation. The actions of Δ9-THCV and Δ9-THCA are less well understood. In contrast to ∆9-THC, CBD has low affinity for CB1 and CB2 receptors and other targets have been investigated to explain its anticonvulsant properties including TRPV1, voltage gated potassium and sodium channels, and GPR55, among others. We describe the absorption, distribution, metabolism, and excretion of each of the above mentioned compounds. Cannabinoids as a whole are very lipophilic, resulting in decreased bioavailability, which presents challenges in optimal drug delivery. Finally, we discuss the limited drug-drug interaction data available on THC and CBD. As cannabinoids and cannabis-based products are studied for efficacy as anticonvulsants, more investigation is needed regarding the specific targets of action, optimal drug delivery, and potential drug-drug interactions.” https://www.ncbi.nlm.nih.gov/pubmed/28087250]]>

Developmental Role of Macrophage Cannabinoid-1 Receptor Signaling in Type-2 Diabetes.

“Islet inflammation promotes β-cell loss and type-2 diabetes (T2D), a process replicated in Zucker Diabetic Fatty (ZDF) rats in which β-cell loss has been linked to cannabinoid-1 receptor (CB1R)-induced pro-inflammatory signaling in macrophages infiltrating pancreatic islets. Here, we analyzed CB1R signaling in macrophages and its developmental role in T2Dα. ZDF rats with global deletion of CB1R are protected from β-cell loss, hyperglycemia and nephropathy present in ZDF littermates. Adoptive transfer of CB1R-/- bone marrow to ZDF rats also prevents β-cell loss and hyperglycemia, but not nephropathy. ZDF islets contain elevated levels of CB1R, IL-1β, TNF-α, the chemokine CCL2 and interferon regulatory factor-5 (IRF5), a marker of M1 inflammatory macrophage polarization. In primary cultured rodent and human macrophages, CB1R activation increased Irf5 expression, whereas knockdown of Irf5 blunted CB1R-induced secretion of inflammatory cytokines without affecting CCL2 expression, which was p38MAPKα-dependent. Macrophage-specific in vivo knockdown of Irf5 protected ZDF rats from β-cell loss and hyperglycemia. Thus, IRF5 is a crucial downstream mediator of diabetogenic CB1R signaling in macrophages and a potential therapeutic target.” https://www.ncbi.nlm.nih.gov/pubmed/28082458]]>

Manipulation of the Endocannabinoid System in Colitis: A Comprehensive Review.

Image result for inflammatory bowel diseases journal “Inflammatory bowel disease (IBD) is a lifelong disease of the gastrointestinal tract whose annual incidence and prevalence is on the rise. Current immunosuppressive therapies available for treatment of IBD offer limited benefits and lose effectiveness, exposing a significant need for the development of novel therapies. In the clinical setting, cannabis has been shown to provide patients with IBD symptomatic relief, although the underlying mechanisms of their anti-inflammatory effects remain unclear.

RESULTS:

Cannabinoid receptors 1 and 2, endogenous cannabinoids, and atypical cannabinoids are upregulated in inflammation, and their presence and stimulation attenuate murine colitis, whereas cannabinoid receptor antagonism and cannabinoid receptor deficient models reverse these anti-inflammatory effects. In addition, inhibition of endocannabinoid degradation through monoacylglycerol lipase and fatty acid amide hydrolase blockade can also attenuate colitis development, and is closely linked to cannabinoid receptor expression.

CONCLUSIONS:

Although manipulation of the endocannabinoid system in murine colitis has proven to be largely beneficial in attenuating inflammation, there is a paucity of human study data. Further research is essential to clearly elucidate the specific mechanisms driving this anti-inflammatory effect for the development of therapeutics to target inflammatory disease such as IBD.” https://www.ncbi.nlm.nih.gov/pubmed/28079617 “Plant cannabinoids THC and CBD proved beneficial in DNBS-induced colitis in a bell-shaped dose-related response, but more importantly, the effects of the phytocannabinoids were additive, as CBD increased an ineffective THC dose to the level of an effective one.” https://academic.oup.com/ibdjournal/article/23/2/192/4347176
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