The endocannabinoid system refers to a widespread signaling system and its alteration is implicated in a growing number of human diseases. However, the potential role of endocannabinoids in skeletal ...muscle disorders remains unknown. Here we report the role of the endocannabinoid CB1 receptors in Duchenne's muscular dystrophy. In murine and human models, CB1 transcripts show the highest degree of expression at disease onset, and then decline overtime. Similar changes are observed for PAX7, a key regulator of muscle stem cells. Bioinformatics and biochemical analysis reveal that PAX7 binds and upregulates the CB1 gene in dystrophic more than in healthy muscles. Rimonabant, an antagonist of CB1, promotes human satellite cell differentiation in vitro, increases the number of regenerated myofibers, and prevents locomotor impairment in dystrophic mice. In conclusion, our study uncovers a PAX7-CB1 cross talk potentially exacerbating DMD and highlights the role of CB1 receptors as target for potential therapies.
Little is known of the involvement of endocannabinoids and cannabinoid receptors in skeletal muscle cell differentiation. We report that, due to changes in the expression of genes involved in its ...metabolism, the levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) are decreased both during myotube formation in vitro from murine C ₂C ₁₂ myoblasts and during mouse muscle growth in vivo. The endocannabinoid, as well as the CB1 agonist arachidonoyl-2-chloroethylamide, prevent myotube formation in a manner antagonized by CB1 knockdown and by CB1 antagonists, which, per se, instead stimulate differentiation. Importantly, 2-AG also inhibits differentiation of primary human satellite cells. Muscle fascicles from CB1 knockout embryos contain more muscle fibers, and postnatal mice show muscle fibers of an increased diameter relative to wild-type littermates. Inhibition of K ᵥ7.4 channel activity, which plays a permissive role in myogenesis and depends on phosphatidylinositol 4,5-bisphosphate (PIP2), underlies the effects of 2-AG. We find that CB1 stimulation reduces both total and K ᵥ7.4-bound PIP2 levels in C ₂C ₁₂ cells and inhibits K ᵥ7.4 currents in transfected CHO cells. We suggest that 2-AG is an endogenous repressor of myoblast differentiation via CB1-mediated inhibition of K ᵥ7.4 channels.
Background and Purpose
Transient receptor potential melastatin type‐8 (TRPM8) is a cold‐sensitive cation channel protein belonging to the TRP superfamily of ion channels. Here, we reveal the ...molecular mechanism of TRPM8 and its clinical relevance in colorectal cancer (CRC).
Experimental Approach
TRPM8 expression and its correlation with the survival rate of CRC patients was analysed. To identify the key pathways and genes related to TRPM8 high expression, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted in CRC patients. TRPM8 functional role was assessed by using Trpm8−/− mice in models of sporadic and colitis‐associated colon cancer. TRPM8 pharmacological targeting by WS12 was evaluated in murine models of CRC.
Key Results
TRPM8 is overexpressed in colon primary tumours and in CD326+ tumour cell fraction. TRPM8 high expression was related to lower survival rate of CRC patients, Wnt–Frizzled signalling hyperactivation and adenomatous polyposis coli down‐regulation. In sporadic and colitis‐associated models of colon cancer, either absence or pharmacological desensitization of TRPM8 reduced tumour development via inhibition of the oncogenic Wnt/β‐catenin signalling. TRPM8 pharmacological blockade reduced tumour growth in CRC xenograft mice by reducing the transcription of Wnt signalling regulators and the activation of β‐catenin and its target oncogenes such as C‐Myc and Cyclin D1.
Conclusion and Implications
Human data provide valuable insights to propose TRPM8 as a prognostic marker with a negative predictive value for CRC patient survival. Animal experiments demonstrate TRPM8 involvement in colon cancer pathophysiology and its potential as a drug target for CRC.
Prostate cancer is highly sensitive to hormone therapy because androgens are essential for prostate cancer cell growth. However, with the nearly invariable progression of this disease to androgen ...independence, endocrine therapy ultimately fails to control prostate cancer in most patients. Androgen-independent acquisition may involve neuroendocrine transdifferentiation, but there is little knowledge about this process, which is presently controversial. In this study, we investigated this question in a novel model of human androgen-dependent LNCaP cells cultured for long periods in hormone-deprived conditions. Strikingly, characterization of the neuroendocrine phenotype by transcriptomic, metabolomic, and other statistically integrated analyses showed how hormone-deprived LNCaP cells could transdifferentiate to a nonmalignantneuroendocrine phenotype. Notably, conditioned media from neuroendocrine-like cells affected LNCaP cell proliferation. Predictive in silico models illustrated how after an initial period, when LNCaP cell survival was compromised by an arising population of neuroendocrine-like cells, a sudden trend reversal occurred in which the neuroendocrine-like cells functioned to sustain the remaining androgen-dependent LNCaP cells. Our findings provide direct biologic and molecular support for the concept that neuroendocrine transdifferentiation in prostate cancer cell populations influences the progression to androgen independence.
Vitamin D deficiency is associated with poor mental health and dysmetabolism. Several metabolic abnormalities are associated with psychotic diseases, which can be compounded by atypical ...antipsychotics that induce weight gain and insulin resistance. These side-effects may be affected by vitamin D levels. The gut microbiota and endocannabinoidome (eCBome) are significant regulators of both metabolism and mental health, but their role in the development of atypical antipsychotic drug metabolic side-effects and their interaction with vitamin D status is unknown. We studied the effects of different combinations of vitamin D levels and atypical antipsychotic drug (olanzapine) exposure on whole-body metabolism and the eCBome-gut microbiota axis in female C57BL/6J mice under a high fat/high sucrose (HFHS) diet in an attempt to identify a link between the latter and the different metabolic outputs induced by the treatments. Olanzapine exerted a protective effect against diet-induced obesity and insulin resistance, largely independent of dietary vitamin D status. These changes were concomitant with olanzapine-mediated decreases in
expression and increases in the levels of its agonists, including various
-acylethanolamines and 2-monoacylglycerols, which are consistent with the observed improvement in adiposity and metabolic status. Furthermore, while global gut bacteria community architecture was not altered by olanzapine, we identified changes in the relative abundances of various commensal bacterial families. Taken together, changes of eCBome and gut microbiota families under our experimental conditions might contribute to olanzapine and vitamin D-mediated inhibition of weight gain in mice on a HFHS diet.
Fish oil (FO) and phytocannabinoids have received considerable attention for their intestinal anti‐inflammatory effects. We investigated whether the combination of FO with cannabigerol (CBG) and ...cannabidiol (CBD) or a combination of all three treatments results in a more pronounced intestinal antiinflammatory action compared to the effects achieved separately. Colitis was induced in mice by 2,4‐dinitrobenzenesulfonic acid (DNBS). CBD and CBG levels were detected and quantified by liquid chromatography coupled with time of flight mass spectrometry and ion trap mass spectrometry (LC‐MS‐IT‐TOF). Endocannabinoids and related mediators were assessed by LC‐MS. DNBS increased colon weight/colon length ratio, myeloperoxidase activity, interleukin‐1β, and intestinal permeability. CBG, but not CBD, given by oral gavage, ameliorated DNBS‐induced colonic inflammation. FO pretreatment (at the inactive dose) increased the antiinflammatory action of CBG and rendered oral CBD effective while reducing endocannabinoid levels. Furthermore, the combination of FO, CBD, and a per se inactive dose of CBG resulted in intestinal anti‐inflammatory effects. Finally, FO did not alter phytocannabinoid levels in the serum and in the colon. By highlighting the apparent additivity between phytocannabinoids and FO, our preclinical data support a novel strategy of combining these substances for the potential development of a treatment of inflammatory bowel disease.
In recent years, several studies have explored the involvement of the deregulation of the hypothalamus–pituitary–adrenal (HPA) axis in the pathophysiology of stress-related disorders. HPA ...hyper-activation as a consequence of acute/chronic stress has been found to play a major role in the neurobiological changes that are responsible for the onset of such states. Currently available medications for depression, one of the most relevant stress-related disorders, present several limitations, including a time lag for treatment response and low rates of efficacy. N-Arachidonoylserotonin (AA-5-HT), a dual blocker at fatty acid amide hydrolase (FAAH, the enzyme responsible for the inactivation of the endocannabinoid anandamide) and transient receptor potential vanilloid type-1 channel (TRPV1), produces anxiolytic-like effects in mice. The present study was designed to assess the capability of AA-5-HT to reverse the behavioral despair following exposure to stress in rats and the role of the HPA-axis. Behavioral tasks were performed, and corticosterone and endocannabinoid (anandamide and 2-arachidonoylglycerol) levels were measured in selected brain areas critically involved in the pathophysiology of stress-related disorders (medial PFC and hippocampus) under basal and stress conditions, and in response to treatment with AA-5-HT. Our data show that AA-5-HT reverses the rat behavioral despair in the forced swim test under stress conditions, and this effect is associated with the normalization of the HPA-axis deregulation that follows stress application and only in part with elevation of anandamide levels. Blockade of FAAH and TRPV1 may thus represent a novel target to design novel therapeutic strategies for the treatment of stress-related disorders.
Background and Purpose
N‐Acylethanolamine acid amidase (NAAA) is a lysosomal enzyme accountable for the breakdown of N‐acylethanolamines (NAEs) and its pharmacological inhibition has beneficial ...effects in inflammatory conditions. The knowledge of NAAA in cancer is fragmentary with an unclarified mechanism, whereas its contribution to colorectal cancer (CRC) is unknown to date.
Experimental Approach
CRC xenograft and azoxymethane models were used to assess the in vivo effect of NAAA inhibition. Further, the tumour secretome was evaluated by an oncogenic array, CRC cell lines were used for in vitro studies, cell cycle was analysed by cytofluorimetry, NAAA was knocked down with siRNA, human biopsies were obtained from surgically resected CRC patients, gene expression was measured by RT‐PCR and NAEs were measured by LC–MS.
Key Results
The NAAA inhibitor AM9053 reduced CRC xenograft tumour growth and counteracted tumour development in the azoxymethane model. NAAA inhibition affected the composition of the tumour secretome inhibiting the expression of EGF family members. In CRC cells, AM9053 reduced proliferation with a mechanism mediated by PPAR‐α and TRPV1. AM9053 induced cell cycle arrest in the S phase associated with cyclin A2/CDK2 down‐regulation. NAAA knock‐down mirrored the effects of NAAA inhibition with AM9053. NAAA expression was down‐regulated in human CRC tissues, with a consequential augmentation of NAE levels and dysregulation of some of their targets.
Conclusion and Implications
Our results show novel data on the functional importance of NAAA in CRC progression and the mechanism involved. We propose that this enzyme is a valid drug target for the treatment of CRC growth and development.
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LLC-PK1 cells, an immortalized epithelial cell line derived from pig renal proximal tubules, express all the major players of the endocannabinoid system (ECS) such as CB1, CB2 and ...TRPV1 receptors, as well as the main enzymes involved in the biosynthesis and degradation of the major endocannabinoids named 2-arachidonoylglycerol, 2-AG and anandamide, AEA. Here we investigated whether the damages caused by ischemic insults either in vitro using LLC-PK1 cells exposed to antimycin A (an inductor of ATP-depletion) or in vivo using Wistar rats in a classic renal ischemia and reperfusion (IR) protocol, lead to changes in AEA and 2-AG levels, as well as altered expression of genes from the main enzymes involved in the regulation of the ECS. Our data show that the mRNA levels of the CB1 receptor gene were downregulated, while the transcript levels of monoacylglycerol lipase (MAGL), the main 2-AG degradative enzyme, were upregulated in LLC-PK1 cells after IR model. Accordingly, IR was accompanied by a significant reduction in the levels of 2-AG and AEA, as well as of the two endocannabinoid related molecules, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in LLC-PK1 cells. In kidney cortex homogenates, only AEA levels were significantly decreased. In addition, we found that in both the in vitro and in vivo model IR caused a reduction in the expression and activity of the Na+/K+ ATPase. These changes were reversed by the CB1/CB2 agonist WIN55,212, in a CB1-receptor dependent manner in the LLC-PK1 IR model. In conclusion, the ECS and Na+/K+ ATPase are down-regulated following IR in LLC-PK1 cells and rat kidney. We suggest that CB1 agonists might represent a potential strategy to reverse the consequences of IR injury in kidney tissues.
Significance
Although CB1 cannabinoid receptors control skeletal muscle insulin signaling, little is known of their role in muscle formation during differentiation from myoblasts to myotubes. The ...voltage-dependent K
v
7 K
+
channels, which are tonically activated by the membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2), instead activate myotube formation. We found that the levels of the endogenous CB1 agonist 2-arachidonoylglycerol are decreased during murine myoblast differentiation into myotubes, whereas CB1 expression is up-regulated. CB1 activation inhibits myotube formation. This effect is exerted by reducing PIP2 binding to K
v
7.4, which represents the K
v
7 subunit responsible for the pro-myogenic effects. Accordingly, CB1 activation inhibits K
v
7.4-mediated currents in transfected CHO cells. The endocannabinoid system might thus play a role in skeletal muscle dystrophies.
Little is known of the involvement of endocannabinoids and cannabinoid receptors in skeletal muscle cell differentiation. We report that, due to changes in the expression of genes involved in its metabolism, the levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) are decreased both during myotube formation in vitro from murine C
2
C
12
myoblasts and during mouse muscle growth in vivo. The endocannabinoid, as well as the CB1 agonist arachidonoyl-2-chloroethylamide, prevent myotube formation in a manner antagonized by CB1 knockdown and by CB1 antagonists, which, per se, instead stimulate differentiation. Importantly, 2-AG also inhibits differentiation of primary human satellite cells. Muscle fascicles from CB1 knockout embryos contain more muscle fibers, and postnatal mice show muscle fibers of an increased diameter relative to wild-type littermates. Inhibition of K
v
7.4 channel activity, which plays a permissive role in myogenesis and depends on phosphatidylinositol 4,5-bisphosphate (PIP2), underlies the effects of 2-AG. We find that CB1 stimulation reduces both total and K
v
7.4-bound PIP2 levels in C
2
C
12
cells and inhibits K
v
7.4 currents in transfected CHO cells. We suggest that 2-AG is an endogenous repressor of myoblast differentiation via CB1-mediated inhibition of K
v
7.4 channels.
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