Neuroinflammation is a physiological response aimed at maintaining the homodynamic balance and providing the body with the fundamental resource of adaptation to endogenous and exogenous stimuli. ...Although the response is initiated with protective purposes, the effect may be detrimental when not regulated. The physiological control of neuroinflammation is mainly achieved via regulatory mechanisms performed by particular cells of the immune system intimately associated with or within the nervous system and named "non-neuronal cells." In particular, mast cells (within the central nervous system and in the periphery) and microglia (at spinal and supraspinal level) are involved in this control, through a close functional relationship between them and neurons (either centrally, spinal, or peripherally located). Accordingly, neuroinflammation becomes a worsening factor in many disorders whenever the non-neuronal cell supervision is inadequate. It has been shown that the regulation of non-neuronal cells-and therefore the control of neuroinflammation-depends on the local "
" synthesis of the endogenous lipid amide Palmitoylethanolamide and related endocannabinoids. When the balance between synthesis and degradation of this bioactive lipid mediator is disrupted in favor of reduced synthesis and/or increased degradation, the behavior of non-neuronal cells may not be appropriately regulated and neuroinflammation exceeds the physiological boundaries. In these conditions, it has been demonstrated that the increase of endogenous Palmitoylethanolamide-either by decreasing its degradation or exogenous administration-is able to keep neuroinflammation within its physiological limits. In this review the large number of studies on the benefits derived from oral administration of micronized and highly bioavailable forms of Palmitoylethanolamide is discussed, with special reference to neuroinflammatory disorders.
Background and Purpose
Palmitoylethanolamide (PEA) is an endogenous congener of anandamide and potentiates its actions at cannabinoid CB1 and CB2 receptors, and at transient receptor potential ...vanilloid type‐1 (TRPV1) channels. The other endocannabinoid, 2‐arachidonoylglycerol (2‐AG), was recently suggested to act as a TRPV1 channel agonist. We investigated if PEA enhanced levels of 2‐AG in vitro or in vivo and 2‐AG activity at TRPV1 channels.
Experimental Approach
Endogenous lipid levels were measured by LC‐MS in (i) human keratinocytes incubated with PEA (10–20 μM, 40 min, 6 and 24 h, 37°C); (ii) the blood of spontaneously Ascaris suum hypersensitive beagle dogs given a single oral dose of ultramicronized PEA (30 mg·kg−1, 1, 2, 4 and 8 h from administration); (iii) the blood of healthy volunteers given a single oral dose of micronized PEA (300 mg, 2, 4 and 6 h from administration). Effects of 2‐AG at TRPV1 channels were assessed by measuring intracellular Ca2+ in HEK‐293 cells over‐expressing human TRPV1 channels.
Key Results
PEA elevated 2‐AG levels in keratinocytes (∼3‐fold) and in human and canine plasma (∼2 and ∼20‐fold respectively). 2‐AG dose‐dependently raised intracellular Ca2+ in HEK‐293‐TRPV1 cells in a TRPV1‐dependent manner and desensitized the cells to capsaicin. PEA only slightly enhanced 2‐AG activation of TRPV1 channels, but significantly increased 2‐AG‐induced TRPV1 desensitization to capsaicin (IC50 from 0.75 ± 0.04 to 0.45 ± 0.02 μM, with PEA 2 μM).
Conclusions and Implications
These observations may explain why several effects of PEA are attenuated by cannabinoid receptor or TRPV1 channel antagonists.
Linked Articles
This article is part of a themed section on Endocannabinoids. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.7/issuetoc
BACKGROUND AND PURPOSE
Cannabinoid receptor activation induces prostate carcinoma cell (PCC) apoptosis, but cannabinoids other than Δ9‐tetrahydrocannabinol (THC), which lack potency at cannabinoid ...receptors, have not been investigated. Some of these compounds antagonize transient receptor potential melastatin type‐8 (TRPM8) channels, the expression of which is necessary for androgen receptor (AR)‐dependent PCC survival.
EXPERIMENTAL APPROACH
We tested pure cannabinoids and extracts from Cannabis strains enriched in particular cannabinoids (BDS), on AR‐positive (LNCaP and 22RV1) and ‐negative (DU‐145 and PC‐3) cells, by evaluating cell viability (MTT test), cell cycle arrest and apoptosis induction, by FACS scans, caspase 3/7 assays, DNA fragmentation and TUNEL, and size of xenograft tumours induced by LNCaP and DU‐145 cells.
KEY RESULTS
Cannabidiol (CBD) significantly inhibited cell viability. Other compounds became effective in cells deprived of serum for 24 h. Several BDS were more potent than the pure compounds in the presence of serum. CBD‐BDS (i.p.) potentiated the effects of bicalutamide and docetaxel against LNCaP and DU‐145 xenograft tumours and, given alone, reduced LNCaP xenograft size. CBD (1–10 µM) induced apoptosis and induced markers of intrinsic apoptotic pathways (PUMA and CHOP expression and intracellular Ca2+). In LNCaP cells, the pro‐apoptotic effect of CBD was only partly due to TRPM8 antagonism and was accompanied by down‐regulation of AR, p53 activation and elevation of reactive oxygen species. LNCaP cells differentiated to androgen‐insensitive neuroendocrine‐like cells were more sensitive to CBD‐induced apoptosis.
CONCLUSIONS AND IMPLICATIONS
These data support the clinical testing of CBD against prostate carcinoma.
LINKED ARTICLE This article is commented on by Pacher et al., pp. 76–78 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476‐5381.2012.02121.x
Lam. is a tropical plant widely used in traditional medicines and as a food supplement. It is characterized by the presence of glucosinolates and isothiocyanates; the stable isothiocyanate ...4-(α-l-rhamnosyloxy)benzylisothiocyanate (moringin) has been widely studied for its bioactivity as hypoglycemic, antimicrobial, anticancer and in particular for its involvement in nociception and neurogenic pain. Moringa extracts and pure moringin were submitted to in vitro assays with the somatosensory TRPA1 ion channel, proving that moringin is a potent and effective agonist of this receptor involved in nociceptive function and pain states. Moringin do not activate or activates very weakly the vanilloids somatosensory channels TRPV1,2,3 and 4, and the melastatin cooling receptor TRPM8. The comparison of moringin's activity with other known agonists of natural origin is also discussed.
BACKGROUND AND PURPOSE Cannabidiol (CBD) and Δ9‐tetrahydrocannabinol (THC) interact with transient receptor potential (TRP) channels and enzymes of the endocannabinoid system.
EXPERIMENTAL APPROACH ...The effects of 11 pure cannabinoids and botanical extracts botanical drug substance (BDS) from Cannabis varieties selected to contain a more abundant cannabinoid, on TRPV1, TRPV2, TRPM8, TRPA1, human recombinant diacylglycerol lipase α (DAGLα), rat brain fatty acid amide hydrolase (FAAH), COS cell monoacylglycerol lipase (MAGL), human recombinant N‐acylethanolamine acid amide hydrolase (NAAA) and anandamide cellular uptake (ACU) by RBL‐2H3 cells, were studied using fluorescence‐based calcium assays in transfected cells and radiolabelled substrate‐based enzymatic assays. Cannabinol (CBN), cannabichromene (CBC), the acids (CBDA, CBGA, THCA) and propyl homologues (CBDV, CBGV, THCV) of CBD, cannabigerol (CBG) and THC, and tetrahydrocannabivarin acid (THCVA) were also tested.
KEY RESULTS CBD, CBG, CBGV and THCV stimulated and desensitized human TRPV1. CBC, CBD and CBN were potent rat TRPA1 agonists and desensitizers, but THCV‐BDS was the most potent compound at this target. CBG‐BDS and THCV‐BDS were the most potent rat TRPM8 antagonists. All non‐acid cannabinoids, except CBC and CBN, potently activated and desensitized rat TRPV2. CBDV and all the acids inhibited DAGLα. Some BDS, but not the pure compounds, inhibited MAGL. CBD was the only compound to inhibit FAAH, whereas the BDS of CBC > CBG > CBGV inhibited NAAA. CBC = CBG > CBD inhibited ACU, as did the BDS of THCVA, CBGV, CBDA and THCA, but the latter extracts were more potent inhibitors.
CONCLUSIONS AND IMPLICATIONS These results are relevant to the analgesic, anti‐inflammatory and anti‐cancer effects of cannabinoids and Cannabis extracts.
LINKED ARTICLES This article is part of a themed issue on Cannabinoids in Biology and Medicine. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.163.issue‐7
Palmitoylethanolamide (PEA) is a pleiotropic endogenous lipid mediator currently used as a "dietary food for special medical purposes" against neuropathic pain and neuro-inflammatory conditions. ...Several mechanisms underlie PEA actions, among which the "entourage" effect, consisting of PEA potentiation of endocannabinoid signaling at either cannabinoid receptors or transient receptor potential vanilloid type-1 (TRPV1) channels. Here, we report novel molecular mechanisms through which PEA controls mast cell degranulation and substance P (SP)-induced histamine release in rat basophilic leukemia (RBL-2H3) cells, a mast cell model.
RBL-2H3 cells stimulated with SP were treated with PEA in the presence and absence of a cannabinoid type-2 (CB2) receptor antagonist (AM630), or a diacylglycerol lipase (DAGL) enzyme inhibitor (OMDM188) to inhibit the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). The release of histamine was measured by ELISA and β-hexosaminidase release and toluidine blue staining were used as indices of degranulation. 2-AG levels were measured by LC-MS. The mRNA expression of proposed PEA targets (Cnr1, Cnr2, Trpv1, Ppara and Gpr55), and of PEA and endocannabinoid biosynthetic (Napepld, Dagla and Daglb) and catabolic (Faah, Naaa and Mgl) enzymes were also measured. The effects of PEA on the activity of DAGL-α or -β enzymes were assessed in COS-7 cells overexpressing the human recombinant enzyme or in RBL-2H3 cells, respectively.
SP increased the number of degranulated RBL-2H3 cells and triggered the release of histamine. PEA counteracted these effects in a manner antagonized by AM630. PEA concomitantly increased the levels of 2-AG in SP-stimulated RBL-2H3 cells, and this effect was reversed by OMDM188. PEA significantly stimulated DAGL-α and -β activity and, consequently, 2-AG biosynthesis in cell-free systems. Co-treatment with PEA and 2-AG at per se ineffective concentrations downmodulated SP-induced release of histamine and degranulation, and this effect was reversed by OMDM188.
Activation of CB2 underlies the inhibitory effects on SP-induced RBL-2H3 cell degranulation by PEA alone. We demonstrate for the first time that the effects in RBL-2H3 cells of PEA are due to the stimulation of 2-AG biosynthesis by DAGLs.
Background and Purpose
Duchenne muscular dystrophy (DMD), caused by dystrophin deficiency, results in chronic inflammation and irreversible skeletal muscle degeneration. Moreover, the associated ...impairment of autophagy greatly contributes to the aggravation of muscle damage. We explored the possibility of using non‐euphoric compounds present in Cannabis sativa, cannabidiol (CBD), cannabidivarin (CBDV) and tetrahydrocannabidivarin (THCV), to reduce inflammation, restore functional autophagy and positively enhance muscle function in vivo.
Experimental Approach
Using quantitative PCR, western blots and Ca2+i measurements, we explored the effects of CBD and CBDV on the differentiation of both murine and human skeletal muscle cells as well as their potential interaction with TRP channels. Male dystrophic mdx mice were injected i.p. with CBD or CBDV at different stages of the disease. After treatment, locomotor tests and biochemical analyses were used to evaluate their effects on inflammation and autophagy.
Key Results
CBD and CBDV promoted the differentiation of murine C2C12 myoblast cells into myotubes by increasing Ca2+i mostly via TRPV1 activation, an effect that undergoes rapid desensitization. In primary satellite cells and myoblasts isolated from healthy and/or DMD donors, not only CBD and CBDV but also THCV promoted myotube formation, in this case, mostly via TRPA1 activation. In mdx mice, CBD (60 mg·kg−1) and CBDV (60 mg·kg−1) prevented the loss of locomotor activity, reduced inflammation and restored autophagy.
Conclusion and Implications
We provide new insights into plant cannabinoid interactions with TRP channels in skeletal muscle, highlighting a potential opportunity for novel co‐adjuvant therapies to prevent muscle degeneration in DMD patients.
Linked Articles
This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc
There is growing evidence that perturbation of the gut microbiome, known as "dysbiosis", is associated with the pathogenesis of human and veterinary diseases that are not restricted to the ...gastrointestinal tract. In this regard, recent studies have demonstrated that dysbiosis is linked to the pathogenesis of central neuroinflammatory disorders, supporting the existence of the so-called microbiome-gut-brain axis. The endocannabinoid system is a recently recognized lipid signaling system and termed endocannabinoidome monitoring a variety of body responses. Accumulating evidence demonstrates that a profound link exists between the gut microbiome and the endocannabinoidome, with mutual interactions controlling intestinal homeostasis, energy metabolism and neuroinflammatory responses during physiological conditions. In the present review, we summarize the latest data on the microbiome-endocannabinoidome mutual link in health and disease, focalizing the attention on gut dysbiosis and/or altered endocannabinoidome tone that may distort the bidirectional crosstalk between these two complex systems, thus leading to gastrointestinal and metabolic diseases (e.g., idiopathic inflammation, chronic enteropathies and obesity) as well as neuroinflammatory disorders (e.g., neuropathic pain and depression). We also briefly discuss the novel possible dietary interventions based not only on probiotics and/or prebiotics, but also, and most importantly, on endocannabinoid-like modulators (e.g., palmitoylethanolamide) for intestinal health and beyond.
(L.) Scop. is a wild common plant of the Brassicaceae family. It is known as "the singers' plant" for its traditional use in treating aphonia and vocal disability. Despite its wide use in herbal ...preparations, the molecular mechanism of action of
extracts is not known. The plant is rich in glucosinolates and isothiocyanates, which are supposed to be its active compounds. Some members of this family, in particular allylisothiocyanate, are strong agonists of the transient receptor potential ankyrin 1 (TRPA1) channel, which is involved in the somatosensory perception of pungency as well as in the nociception pathway of inflammatory pain. This study aims to isolate the glucosinolates and isothiocianates from fresh
to identify the major components and test their activity in in vitro assays with a cloned TRPA1 channel. Samples of cultivated
have been extracted and the active compounds isolated by column chromatography, HPLC and PTLC. The main components glucoputranjivin, isopropylisothiocyanate and 2-buthylisothiocianate have been tested on TRPA1. The glucosinolates glucoputranjivin and sinigrin turned out to be inactive, while isopropylisothiocyanate and 2-buthylisothiocyanate are potent agonists of TRPA1, with an EC
in the range of the high potency natural agonists identified so far for this somatosensory channel.
Palmitoylethanolamide (PEA) is a pleiotropic lipid mediator with established anti-inflammatory and anti-hyperalgesic activity. Ultramicronized PEA (PEA-um) has superior oral efficacy compared to ...naïve (non-micronized) PEA. The aim of the present study was two-fold: (1) to evaluate whether oral PEA-um has greater absorbability compared to naïve PEA, and its ability to reach peripheral and central tissues under healthy and local inflammatory conditions (carrageenan paw edema); (2) to better characterize the molecular pathways involved in PEA-um action, particularly at the spinal level. Rats were dosed with 30 mg/kg of
C
-PEA-um or naïve
C
-PEA by oral gavage, and
C
-PEA levels quantified, as a function of time, by liquid chromatography/atmospheric pressure chemical ionization/mass spectrometry. Overall plasma levels were higher in both healthy and carrageenan-injected rats administered
C
-PEA-um as compared to those receiving naïve
C
-PEA, indicating the greater absorbability of PEA-um. Furthermore, carrageenan injection markedly favored an increase in levels of
C
-PEA in plasma, paw and spinal cord. Oral treatment of carrageenan-injected rats with PEA-um (10 mg/kg) confirmed beneficial peripheral effects on paw inflammation, thermal hyperalgesia and tissue damage. Notably, PEA-um down-regulated distinct spinal inflammatory and oxidative pathways. These last findings instruct on spinal mechanisms involved in the anti-hyperalgesic effect of PEA-um in inflammatory pain.
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