title: What we know and do not know about the cannabinoid receptor 2 (CB2).
abstract: It has been well appreciated that the endocannabinoid system can regulate immune responses via the cannabinoid receptor 2 (CB2), which is primarily expressed by cells of the hematopoietic system. The endocannabinoid system is composed of receptors, ligands and enzymes controlling the synthesis and degradation of endocannabinoids. Along with endocannabinoids, both plant-derived and synthetic cannabinoids have been shown to bind to and signal through CB2 via G proteins leading to both inhibitory and stimulatory signals depending on the biological process. Because no cannabinoid ligand has been identified that only binds to CB2, the generation of mice deficient in CB2 has greatly expanded our knowledge of how CB2 contributes to immune cell development and function in health and disease. In regards to humans, genetic studies have associated CB2 with a variety of human diseases. Here, we review the endocannabinoid system with an emphasis on CB2 and its role in the immune system.
authors.affiliation: Dipartimento di Medicina e Chirurgia, Università di Salerno Facoltà di Medicina, Baronissi Campus, Baronissi 84081, (SA), Italy; Dipartimento di Farmacia, Università di Salerno, Fisciano 84084, (SA), Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Malfitano
authors.affiliation: Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA.
authors.forename: Sreemanti
authors.initials: S
authors.lastname: Basu
authors.affiliation: Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Maresz
authors.affiliation: Dipartimento di Medicina e Chirurgia, Università di Salerno Facoltà di Medicina, Baronissi Campus, Baronissi 84081, (SA), Italy; Dipartimento di Farmacia, Università di Salerno, Fisciano 84084, (SA), Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bifulco
authors.affiliation: Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA. Electronic address: bonnie.dittel@bcw.edu.
authors.forename: Bonnie N
authors.initials: BN
authors.lastname: Dittel
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000276:immunology / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D063388:Endocannabinoids / Q000276:immunology / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007107:Immune System / Q000378:metabolism*; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D010024:Osteoporosis / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010944:Plants / Q000235:genetics / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D016207:Cytokines; D063388:Endocannabinoids; D043885:Receptor, Cannabinoid, CB2; D043562:Receptors, G-Protein-Coupled
keywords: Cannabinoid receptor 2; Endocannabinoid; Immune regulatory; Knockout; Polymorphism