Recent studies suggest a role for the endocannabinoid/endovanilloid anandamide in the regulation of bone resorption/formation balance in mice. Here, we examined the co-expression of the transient receptor potential vanilloid type 1 (TRPV1) and the cannabinoid CB1/CB2 receptors together with N-acylphosphatidylethanolamine-hydrolizing phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), the two enzymes responsible of the synthesis and catabolism of anandamide respectively, in human osteoclasts. Co-expression of TRPV1, CB1/CB2, NAPE-PLD and FAAH was found in both human osteoclast cultures and in native osteoclasts from human bone biopsies. Moreover, agonist-evoked calcium entry indicated that the TRPV1 receptor is functionally active in vitro. Consistently, biomolecular and functional experiments showed that resiniferatoxin (RTX), a selective TRPV1 receptor agonist, increased the expression and the activity of TRAP and cathepsin K, two specific osteoclast biomarkers. The evidence that cannabinoid and vanilloid receptors are co-expressed in human osteoclasts suggests that they might cross-talk to modulate the intrinsic balance of bone mineralization and resorption by different actions of anandamide through TRPV1 and cannabinoid receptors. The presence of the endocannabinoid/endovanilloid proteins in human osteoclasts will likely have implications for the management of bone demineralization associated syndrome (i.e. osteoporosis). (C) 2008 Elsevier Inc. All rights reserved.
The endovanilloid/endocannabinoid system in human osteoclasts: Possible involvement in bone formation and resorption
Rossi F.;Siniscalco D.;Luongo L.;Bellini G.;Torella M.;Santoro C.;Nobili B.;Perrotta S.;Maione S.
2009
Abstract
Recent studies suggest a role for the endocannabinoid/endovanilloid anandamide in the regulation of bone resorption/formation balance in mice. Here, we examined the co-expression of the transient receptor potential vanilloid type 1 (TRPV1) and the cannabinoid CB1/CB2 receptors together with N-acylphosphatidylethanolamine-hydrolizing phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH), the two enzymes responsible of the synthesis and catabolism of anandamide respectively, in human osteoclasts. Co-expression of TRPV1, CB1/CB2, NAPE-PLD and FAAH was found in both human osteoclast cultures and in native osteoclasts from human bone biopsies. Moreover, agonist-evoked calcium entry indicated that the TRPV1 receptor is functionally active in vitro. Consistently, biomolecular and functional experiments showed that resiniferatoxin (RTX), a selective TRPV1 receptor agonist, increased the expression and the activity of TRAP and cathepsin K, two specific osteoclast biomarkers. The evidence that cannabinoid and vanilloid receptors are co-expressed in human osteoclasts suggests that they might cross-talk to modulate the intrinsic balance of bone mineralization and resorption by different actions of anandamide through TRPV1 and cannabinoid receptors. The presence of the endocannabinoid/endovanilloid proteins in human osteoclasts will likely have implications for the management of bone demineralization associated syndrome (i.e. osteoporosis). (C) 2008 Elsevier Inc. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
