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In this study, we investigated the role of the endovanilloid/endocannabinoid system in the glucocorticoid-induced osteoclast overactivity. Receptorial and enzymatic component of the endovanilloid/endocannabinoid system are expressed in bone cells, and dysregulated when bone mass is reduced. Moreover, blockade or desensitization of vanilloid receptor 1 (TRPV1) and/or stimulation of cannabinoid receptor 2 (CB2) are beneficial for reducing number and activity of the bone cells modulating resorption, the osteoclasts. We have treated in vitro healthy woman derived osteoclasts with methylprednisolone in presence or not of CB2 or TRPV1 agonists/antagonists, analysing the effect on osteoclast function and morphology through a multidisciplinary approach. Moreover, a treatment with a protein kinase C inhibitor to evaluate osteoclast activity and endovanilloid/endocannabinoid component expression levels was performed in osteoclasts derived from healthy subjects in presence of not of methylprednisolone. Our results show, for the first time, that the endovanilloid/endocannabinoid system is dysregulated by the treatment with methylprednisolone, that the osteoclast activity is increased and that pharmacological compounds stimulating CB2 or inhibiting TRPV1 might reduce, possible inhibiting protein kinase C beta II, the methylprednisolone-induced osteoclast over-activation, suggesting their therapeutic use for protecting from the glucocorticoid-induced bone mass loss., (Copyright © 2016. Published by Elsevier Ltd.)

Context: Obesity is associated with a low-grade inflammatory state and adipocyte (ADP) hyperplasia/hypertrophy. Obesity inhibits the "browning" of white adipose tissue. Cannabinoid receptor 2 (CB2) agonists reduce food intake and induce antiobesity effect in mice. A common missense CB2 variant, Q63R, causes CB2-reduced function., Objective: To evaluate the influence of CB2 receptor on the modulation of childhood obesity and of ADP activity and morphology., Design: CB2-Q63R variant was analyzed in obese Italian children. The effects of an inflammatory stimulus and those of drugs selectively acting on CB2 were investigated on in vitro ADPs obtained from mesenchymal stem cells of adult healthy donors or from sc adipose biopsies of adult nonobese and obese subjects., Setting: Department of Women, Child and General and Specialist Surgery of the Second University of Naples., Patients or Other Participants: A total of 501 obese Italian children (age 11 ± 2.75). Twelve healthy bone marrow donors (age 36.5 ± 15); and 17 subjects, 7 lean (age 42 ± 10) and 10 obese (age 37.8 ± 12) underwent sc adipose tissue biopsies., Main Outcome Measures: Effects of CB2 stimulation on adipokine, perilipin, and uncoupling protein-1 expression., Results: The less-functional CB2-R63 variant was significantly associated with a high z-score body mass index. CB2 blockade with AM630 reverse agonist increased inflammatory adipokine release and fat storage and reduced browning. CB2 stimulation with JWH-133 agonist reversed all of the obesity-related effects., Conclusion: CB2 receptor is a novel pharmacological target that should be considered for obesity.

Background: The ovary is an important site where gene variants modulate pubertal timing. The cannabinoid receptor 2 (CB2) is expressed in the ovary, plays a role in folliculogenesis and ovulation, and can be modulated by estrogens. Obesity is strictly associated with early menarche and is characterized by sex hormone and endocannabinoid derangement., Aim: In this study, we investigated the role of the CB2 receptor in determining the age at menarche in obese girls., Methods: We studied a cohort of 240 obese girls (age 11.9±3 years; BMI z-score 2.8±0.8). The age at menarche (if it had already occurred) was recorded at the time of the visit or via phonecall. The CNR2 rs35761398 polymorphism, which leads to the CB2 Q63R variant, was detected by the TaqMan assay., Results: In total, 105 patients were homozygous for the R63-coding allele (RR), 113 were QR and 22 were QQ. Variance analysis revealed a significantly earlier age of menarche in subjects carrying the Q63 allele, which was also found after adjusting for BMI z-score (11±1.2 vs. 11.6±1.2 years, p = 0.0003). Logistic regression analysis demonstrated that patients homozygous for the Q allele had a 2.2-fold higher risk (odds ratio = 2.2; CI1.1-3.4; p = 0.02) of presenting with an early menarche (age at menarche <12 years)., Conclusion: We demonstrated for the first time the association between the CB2 Q63R functional variant and the age at menarche in a cohort of Italian obese girls.

In the current study, we have investigated the effect of CB2 and TRPV1 receptor ligands on in vitro osteoblasts from bone marrow of human healthy donors. A pivotal role for the endocannabinoid/endovanilloid system in bone metabolism has been highlighted. We have demonstrated a functional cross-talk between CB2 and TRPV1 in human osteoclasts, suggesting these receptors as new pharmacological target for the treatment of bone resorption disease as osteoporosis. Moreover, we have shown the presence of these receptors on human mesenchimal stem cells, hMSCs. Osteoblasts are mononucleated cells originated from hMSCs by the essential transcription factor runt-related transcription factor 2 and involved in bone formation via the synthesis and release of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand and osteoprotegerin. For the first time, we show that CB2 and TRPV1 receptors are both expressed on human osteoblasts together with enzymes synthesizing and degrading endocannabinoids/endovanilloids, and oppositely modulate human osteoblast activity in culture in a way that the CB2 receptor stimulation improves the osteogenesis whereas TRPV1 receptor stimulation inhibits it., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objectives: To investigate whether the functional variant Q63R of the cannabinoid 2 (CB2) receptor is associated with susceptibility to oligo/poly-articular juvenile idiopathic arthritis (JIA) and with its clinical features., Method: A total of 171 Italian children with oligoarticular/rheumatoid factor negative poly-articular JIA and 600 healthy controls were enrolled in the study and genotyped., Results: A significant difference in genotype distribution of the CB2 Q63R variant (CNR2 rs35761398) between oligo/poly-articular JIA patients and controls was found (p = 0.001). The R63 variant was associated with increased rates of relapse (p = 0.0001)., Conclusions: This study indicates that the CB2 receptor contributes to susceptibility to oligo/polyarticular JIA and to the severity of its clinical course.

Background & Aims: The cannabinoid receptor 2 (CB2) has been implicated in liver disease. The single-nucleotide polymorphism rs35761398 in cannabinoid receptor 2 gene (CNR2), which encodes the CB2, substitutes glutamine (Q) 63 with arginine (R), and reduces the function of the gene product. We investigated the effects of CNR2 rs35761398 in patients with hepatitis C virus (HCV) infection., Methods: We studied 169 consecutive patients with asymptomatic chronic hepatitis (tested positive for anti-HCV and HCV RNA) at 2 liver units in southern Italy. First, liver biopsy samples were collected from July 2009 through December 2011. All patients were naive to antiviral therapy; CNR2 genotype was determined by polymerase chain reaction analysis., Results: Patients with the CB2-63 QQ variant had higher serum levels of aminotransferase than those with the CB2-63 QR or RR variants; they also had higher histologic activity index (HAI) scores (8.6 ± 3.8) than patients without the CB2-63 RR variant (5.3 ± 3.6; P < .005) or those with the CB2-63 QR variant (5.8 ± 3.3; P < .001). Patients with the different variants of CNR2 did not differ in fibrosis stage or steatosis score. Moderate or severe chronic hepatitis (HAI score, >8) was identified more frequently (55.5%) in patients with the CB2-63 QQ variant than in those with the 63 QR (20%; P < .005) or RR variants (17.4%; P < .005). In logistic regression analysis, the CB2-63 QQ variant and fibrosis score were independent predictors of moderate or severe chronic hepatitis (HAI score, >8; P < .0001)., Conclusions: The CB2-63 QQ variant of CNR2 is associated with more severe inflammation and hepatocellular necrosis in patients with HCV infection., (Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Mesenchymal stromal cells are non-hematopoietic, multipotent progenitor cells producing cytokines, chemokines, and extracellular matrix proteins that support hematopoietic stem cell survival and engraftment, influence immune effector cell development, maturation, and function, and inhibit alloreactive T-cell responses. The immunosuppressive properties of human mesenchymal stromal cells have attracted much attention from immunologists, stem cell biologists and clinicians. Recently, the presence of the endocannabinoid system in hematopoietic and neural stem cells has been demonstrated. Endocannabinoids, mainly acting through the cannabinoid receptor subtype 2, are able to modulate cytokine release and to act as immunosuppressant when added to activated T lymphocytes. In the present study, we have investigated, through a multidisciplinary approach, the involvement of the endocannabinoids in migration, viability and cytokine release of human mesenchymal stromal cells. We show, for the first time, that cultures of human mesenchymal stromal cells express all of the components of the endocannabinoid system, suggesting a potential role for the cannabinoid CB2 receptor as a mediator of anti-inflammatory properties of human mesenchymal stromal cells, as well as of their survival pathways and their capability to home and migrate towards endocannabinoid sources.

Bone is a highly metabolically active tissue and its formation and resorption is at the base of bone remodelling. The critical importance of a balanced bone remodelling is demonstrated by human diseases, i.e. osteoporosis, in which a net increase in bone resorption is responsible of skeleton weakening and fracture risk. Oestrogens display anti-resorptive properties on bone metabolism. Indeed, the so-called post-menopausal osteoporosis occurs after interruption of gonad function and benefits from hormonal replacement treatment. Recently, an important role for the endocannabinoid system in the regulation of skeletal remodelling in human has also been shown. In particular, we showed that CB2 stimulation is able to reduce the number of human OCs in vitro. Here, we provide unprecedented evidence that 17-β-oestradiol administration inhibits activity and formation of human OCs in vitro, demonstrating that oestrogens are able to induce an increase of CB2 expression probably through the recruitment of a putative oestrogens responsive element in the CB2 encoding for gene., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Celiac disease (CD) is a chronic inflammatory disease of the small bowel that occurs with the ingestion of gluten, found in several grains products. Although HLA-DQ2 variant is required for the gluten-derived peptide gliadin presentation by antigen-presenting cells to T-cells, non-HLA genetic factors account for the majority of heritable risk. Several genome-wide association studies have identified susceptibility loci for CD on chromosome 1. Cells of the immune system express the cannabinoid receptor type 2 (CB2), a plasma-membrane receptor activated by both endogenous and exogenous cannabinoids. Consistent data evidence that CB2 is linked to a variety of immune functional events and that, in the course of an inflammatory process, an increased number of receptors becomes available for activation. The cannabinoid receptor type 2 gene (CNR2; GeneID1269) maps on 1p36.11. In order to investigate the possible involvement of CB2 in CD establishment, immunohistochemistry toward CB2 receptor and CD4+ cells in small bowel biopsies from celiac children and association analysis, through TaqMan assay, of a CNR2 common missense variant, rs35761398 (CAA/CGG), resulting in the aminoacidic substitution of Glutamine at codon 63 with Arginine (Q63R), in a cohort of 327 South Italian children have been performed. We observed in this study that CB2 is up-regulated in CD small bowel biopsies and CNR2 rs35761398 is significantly associated with CD (χ(2) = 37.064; d.f. 1; p = 1.14 × 10(-9)). Our findings suggest a role of CB2 in CD. The Q63R variant, increasing more than six-fold the risk for CD susceptibility, might eventually represent a novel molecular biomarker for CD risk stratification. Indeed, we provide here further evidence that CB2 receptor plays a critical role in autoimmunity susceptibility and indicates that it represents a molecular target to pharmacologically modulate the immune components in CD., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Immune thrombocytopenic purpura is an acquired autoimmune disorder that is the most common cause of thrombocytopenia in children. The endocannabinoid system is involved in immune regulation. We evaluated a common missense variant (CAA/CGG; Q63R) of the gene encoding the cannabinoid receptor type 2 (GeneID 1269) in 190 children with immune thrombocytopenic purpura and 600 healthy controls. The allelic frequencies and genotype distribution of the polymorphism in the patients were significant compared to control samples (P=0.006 and P=0.0001, respectively). Interestingly, when acute and chronic immune thrombocytopenic purpura patients were analyzed separately with respect to controls, a significant overrepresentation of the RR genotype and of the R allele was observed only for the chronic form (P=0.00021 and P=0.011, respectively). The relative odds ratio suggested the risk of developing chronic form was more than double in immune thrombocytopenic purpura children homozygous for the variant (odds ratio=2.349, 95% CI: 1.544-3.573; P<0.001).