Palmitoylethanolamide reduces granuloma-induced hyperalgesia by modulation of mast cell activation in rats

The aim of this study was to obtain evidences of a possible analgesic role for palmitoylethanolamide (PEA) in chronic granulomatous inflammation sustained by mast cell (MC) activation in rats at 96 hours. PEA (200-400-800 μg/mL), locally administered at time 0, reduced in a concentration-dependent manner the expression and release of NGF in comparison with saline-treated controls. PEA prevented nerve formation and sprouting, as shown by histological analysis, reduced mechanical allodynia, evaluated by Von Frey filaments, and inhibited dorsal root ganglia activation. These results were supported by the evidence that MCs in granuloma were mainly degranulated and closely localized near nerve fibres and PEA significantly reduced MC degranulation and nerves fibre formation. These findings are the first evidence that PEA, by the modulation of MC activation, controls pain perception in an animal model of chronic inflammation, suggesting its potential use for the treatment of all those painful conditions in which MC activation is an initial key step

Differential Cannabinoid Receptor Expression during Reactive Gliosis: a Possible Implication for a Nonpsychotropic Neuroprotection

Activated microglia and astrocytes produce a large number of inflammatory and neurotoxic substances in various brain pathologies, above all during neurodegenerative disorders. In the search for new neuroprotective compounds, interest has turned to marijuana derivatives, since in several in vitro, in vivo, and clinical studies, they have shown a great ability to control neuroinflammation

Palmitoylethanolamide inhibits rMCP-5 expression by regulating MITF activation in rat chronic granulomatous inflammation

Chronic inflammation, a condition frequently associated with several pathologies, is characterized by angiogenic and fibrogenic responses that may account for the development of granulomatous tissue. We previously demonstrated that the chymase, rat mast cell protease-5 (rMCP-5), exhibits pro-inflammatory and pro-angiogenic properties in a model of chronic inflammation sustained by mast cells (MCs), granuloma induced by the subcutaneous carrageenan-soaked sponge implant in rat. In this study, we investigated the effects of palmitoylethanolamide (PEA), an anti-inflammatory and analgesic endogenous compound, on rMCP-5 mRNA expression and Microphtalmia-associated Transcription Factor (MITF) activation in the same model of chronic inflammation. The levels of rMCP-5 mRNA were detected using semi-quantitative RT-PCR; the protein expression of chymase and extracellular signal-regulated kinases (ERK) were analyzed by western blot; MITF/DNA binding activity and MITF phosphorylation were assessed by electrophoretic mobility shift assay (EMSA) and immunoprecipitation, respectively. The administration of PEA (200, 400 and 800 µg/ml) significantly decreased rMCP-5 mRNA and chymase protein expression induced by λ-carrageenan. These effects were associated with a significant decrease of MITF/DNA binding activity and phosphorylated MITF as well as phosphorylated ERK levels. In conclusion, our results, showing the ability of PEA to inhibit MITF activation and chymase expression in granulomatous tissue, may yield new insights into the understanding of the signaling pathways leading to MITF activation controlled by PEA

Cannabidiol Reduces Intestinal Inflammation through the Control of Neuroimmune Axis

Enteric glial cells (EGC) actively mediate acute and chronic inflammation in the gut; EGC proliferate and release neurotrophins, growth factors, and pro-inflammatory cytokines which, in turn, may amplify the immune response, representing a very important link between the nervous and immune systems in the intestine. Cannabidiol (CBD) is an interesting compound because of its ability to control reactive gliosis in the CNS, without any unwanted psychotropic effects. Therefore the rationale of our study was to investigate the effect of CBD on intestinal biopsies from patients with ulcerative colitis (UC) and from intestinal segments of mice with LPS-induced intestinal inflammation. CBD markedly counteracted reactive enteric gliosis in LPS-mice trough the massive reduction of astroglial signalling neurotrophin S100B. Histological, biochemical and immunohistochemical data demonstrated that S100B decrease was associated with a considerable decrease in mast cell and macrophages in the intestine of LPS-treated mice after CBD treatment. Moreover the treatment of LPS-mice with CBD reduced TNF-α expression and the presence of cleaved caspase-3. Similar results were obtained in ex vivo cultured human derived colonic biopsies. In biopsies of UC patients, both during active inflammation and in remission stimulated with LPS+INF-γ, an increased glial cell activation and intestinal damage were evidenced. CBD reduced the expression of S100B and iNOS proteins in the human biopsies confirming its well documented effect in septic mice. The activity of CBD is, at least partly, mediated via the selective PPAR-gamma receptor pathway. CBD targets enteric reactive gliosis, counteracts the inflammatory environment induced by LPS in mice and in human colonic cultures derived from UC patients. These actions lead to a reduction of intestinal damage mediated by PPARgamma receptor pathway. Our results therefore indicate that CBD indeed unravels a new therapeutic strategy to treat inflammatory bowel diseases

Cannabidiol Reduces Aβ-Induced Neuroinflammation and Promotes Hippocampal Neurogenesis through PPARγ Involvement

Peroxisome proliferator-activated receptor-γ (PPARγ) has been reported to be involved in the etiology of pathological features of Alzheimer's disease (AD). Cannabidiol (CBD), a Cannabis derivative devoid of psychomimetic effects, has attracted much attention because of its promising neuroprotective properties in rat AD models, even though the mechanism responsible for such actions remains unknown. This study was aimed at exploring whether CBD effects could be subordinate to its activity at PPARγ, which has been recently indicated as its putative binding site. CBD actions on β-amyloid-induced neurotoxicity in rat AD models, either in presence or absence of PPAR antagonists were investigated. Results showed that the blockade of PPARγ was able to significantly blunt CBD effects on reactive gliosis and subsequently on neuronal damage. Moreover, due to its interaction at PPARγ, CBD was observed to stimulate hippocampal neurogenesis. All these findings report the inescapable role of this receptor in mediating CBD actions, here reported

ALIAmides: EXPERIMENTAL STUDIES ON THE CONTROL OF ANGIOGENESIS

Generally, pathological conditions or altered physiological events are the consequences of different mechanisms altering the normal homeostasis. Between these events, angiogenesis that is the process that brings to the formation of new blood vessels from pre-existing ones, plays a very important role. The angiogenic process begins with capillary sprouting and culminates in formation of a new microcirculatory bed composed of arterioles, capillaries and venules. The initiation of angiogenesis consists of at least three processes: 1) breakdown of the basement membrane of the existing vessels, 2) migration of endothelial cells from the existing vessels towards an angiogenic stimulus, and 3) proliferation of endothelial cells (Klagsbrun & D’Amore, 1991). Physiological angiogenesis occurs during wound healing, organ regeneration, and in the female reproductive system during ovulation, menstruation, and the formation of the placenta; however, angiogenesis also occurs in pathological processes such as tumour growth, rheumatoid arthritis, diabetic retinopathy, and psoriasis. A switch to the angiogenic phenotype depends on a local change in the balance between angiogenic stimulators and inhibitors (Post et al., 2008), since this series of events is subject to a tight control played by the “angiogenic balance”, i.e. a physiological balance between the stimulatory and inhibitory signals for blood vessel growth, tightly controls angiogenesis (Folkman, 1995). Growing evidences suggest that angiogenesis occurs in the development of human pathologies affecting the Central Nervous System (CNS) too, although its role is controversial. In fact, new vascularisation should be protective in post- ischemic brain (Beck et al., 2009), in cerebral stroke (Arai et al., 2009), and in spinal cord injury (Han et al., 2010), where oxygen replacement is beneficial for neuronal cell survival in a hypoxic region. On the other hand, angiogenesis can be detrimental where inflammatory foci exist within the CNS, as in some neurodegenerative disorders (Candelario et al., 2009), since new blood supply may promote the increase of pro-oxidant, pro-inflammatory, and also pro- angiogenic mediators into the brain. Among these neurodegenerative conditions, a negative role of angiogenesis has been recently described during Alzheimer Disease (Fioravanzo et al., 2010). In fact, it seems to be clear that, during hyperactivation of astroglial cells, where a scenario of “reactive gliosis” is already in progress, the formation of new vessels gets the damaged area worse, in relation to the increase of pro-oxidant, pro-inflammatory and pro- angiogenic mediators and despite the assumption that angiogenesis brings oxygen and nutrients to the hypoxic place (Chrystov et al., 2006). In the periphery, a different cell type, mast cell, plays similarly to astroglia during neurodegeneration in sustaining angiogenic process. Actually, several evidences have shown the important role of mast cells in supporting angiogenesis (Iuvone et al., 1999), since their critical presence near sites of new capillary sprouting is a fundamental event for the new vessel formation. In fact, during specific pathological conditions, such as inflammatory or allergic diseases, mast cells become activated and allowed to degranulate, in releasing a series of pro- angiogenic mediators (VEGF, MMPs, TNF- α). In parallel, a new class of compounds, ALIAmides, (Autacoid Local Injury Antagonism Amides) possessing in vitro and in vivo anti- angiogenic activities, has been discovered (Aloe et al., 1993). Between these, recently it has been reported that Palmitoylethanolamide, ALIAmides’ ancestor, is able to inhibit both astroglial and mast cell activation (Scuderi et al., 2011; De Filippis et al., 2010). These evidences are the scientific starting point of my Ph.D. thesis, focused on studying the modulation of angiogenesis by ALIAmides through the control of astroglial and mast cell behaviour and leading, and, as a consequence, a modulation of both CNS and peripheral pathological inflammatory conditions

Association between cannabinoid CB1 receptor expression and Akt signalling in prostate cancer

Background: In prostate cancer, tumour expression of cannabinoid CB1 receptors is associated with a poor prognosis. One explanation for this association comes from experiments with transfected astrocytoma cells, where a high CB receptor expression recruits the Akt signalling survival pathway. In the present study, we have investigated the association between CB1 receptor expression and the Akt pathway in a well-characterised prostate cancer tissue microarray. Methodology/Principal Findings: Phosphorylated Akt immunoreactivity (pAkt-IR) scores were available in the database. CB1 receptor immunoreactivity (CB1IR) was rescored from previously published data using the same scale as pAkt-IR. There was a highly significant correlation between CB1IR and pAkt-IR. Further, cases with high expression levels of both biomarkers were much more likely to have a more severe form of the disease at diagnosis than those with low expression levels. The two biomarkers had additive effects, rather than an interaction, upon disease-specific survival. Conclusions/Significance: The present study provides data that is consistent with the hypothesis that at a high CB1 receptor expression, the Akt signalling pathway becomes operative

The influence of monoacylglycerol lipase inhibition upon the expression of epidermal growth factor receptor in human PC-3 prostate cancer cells.

Background: It has been reported that direct activation of the cannabinoid CB1 receptor in epidermal growth factor (EGR)-stimulated PC-3 prostate cancer cells results in an anti-proliferative effect accompanied by a down-regulation of EGF receptors (EGFR). In the present study, we investigated whether similar effects are seen following inhibition of the endocannabinoid hydrolytic enzyme monoacylglycerol lipase (MGL). Results: CB1 receptor expression levels were found to differ greatly between two experimental series conducted using PC-3 cells. The monoacylglycerol lipase inhibitor JZL184 increased levels of 2-arachidonoylglycerol in the PC-3 cells without producing changes in the levels of anandamide and related N-acylethanolamines. In the first series of experiments, JZL184 produced a small mitogenic effect for cells that had not been treated with EGF, whereas an anti-proliferative effect was seen for EGF-treated cells. An anti-proliferative effect for the EGF-treated cells was also seen with the CB receptor agonist CP55,940. In the second batch of cells, there was an interaction between JZL184 and CB1 receptor expression densities in linear regression analyses with EGFR expression as the dependent variable. Conclusions: Inhibition of MGL by JZL184 can affect EGFR expression. However, the use in our hands of PC-3 cells as a model to investigate the therapeutic potential of MGL inhibitors and related compounds is compromised by their variability of CB1 receptor expression

Are Anti-Angiogenic Drugs Useful in Neurodegenerative Disorders?

Recently, a pivotal role for neuroinflammation in the pathogenesis of several neurodegenerative diseases has been recognized. Once activated, glial cells produce pathological amounts of neurotoxic substances driving neurodegeneration into chronic progression through a self-propagating cycle. Nevertheless, mounting evidence suggests that also angiogenesis may importantly contribute to neurodegeneration, since activated glial cells may release also pro-angiogenic factors. A deregulation of the balance between pro- and anti-angiogenic mediators has been reported in in vivo and in vitro models of neuroinflammation. Indeed, in Alzheimer's disease brain, a significant increase in the expression of pro- angiogenic growth factors, such as Vvascular endothelial growth factor, was found strictly co-localized with senile plaques. In addition, converging results indicate that thalidomide and its derivatives, having newly discovered anti-inflammatory and anti-angiogenic properties, are useful in the prevention of several hallmarks of neurodegeneration occurring in experimental models of Parkinson's and Alzheimer's diseases. The present review primarily discusses about the possible roles, still under debate, of angiogenesis in neurodegeneration, and focuses on the identification of new possible anti-angiogenic compounds that could open new horizons in the treatment of neurodegenerative diseases where angiogenesis is detrimental