Migration and differentiation of mesenchymal stem cells (MSCs) are known to be involved in various regenerative processes such as bone healing. However, little is known about the pharmacotherapeutical options aiming at the mobilization and differentiation of MSCs. The present study therefore focussed on cannabinoids which have been demonstrated to exhibit tissue healing properties. Using Boyden chamber assays, the non-psychoactive phytocannabinoid cannabidiol (CBD) was found to increase the migration of adipose-derived MSCs in a time- and concentration-dependent manner. CBD-induced migration was inhibited by AM-630 (CB₂ receptor antagonist) and O-1602 (G protein-coupled receptor 55 [GRP55] agonist). Moreover, the promigratory effect of CBD was antagonized by inhibition of the p42/44 mitogen-activated protein kinase (MAPK) pathway which became activated upon CBD treatment. In line with this data, AM-630 and O-1602 attenuated CBD-induced p42/44 MAPK phosphorylation. A p42/44 MAPK-dependent promigratory effect was likewise demonstrated for the GPR55 antagonist O-1918 and the selective CB₂ receptor agonist JWH-133. Additional evidence for a functional effect of CBD on MSCs was provided by experiments demonstrating long-term stimulation with CBD to induce differentiation of MSCs into the osteoblastic lineage as evidenced by increased mineralization assessed by cresolphthalein complexone assay and enhanced activity of alkaline phosphatase. Collectively, this study demonstrates CBD to promote the migration of MSCs via activation of the CB₂ receptor and inhibition of GPR55 and to induce osteoblastic differentiation. CBD may therefore recruit MSCs to sites of calcifying tissue regeneration and subsequently support bone regeneration via an osteoanabolic action on MSCs.
Keywords: (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1.6-benzene disulfonate); (6aR,10aR)-3-(1,1-dimethylbutyl)-6a-,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,-d]pyran, selective CB(2) agonist; 1,3-dimethoxy-5-methyl-2-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]benzene, selective GPR55 antagonist; 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one, inhibitor of p42/44 MAPK activation; 2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride, upstream inhibitor of Akt; 4-amino-5-(4-chlorophenyl)-7-(dimethylethyl)pyrazolo[3,4-d]pyrimidine, kinase inhibitor, upstream inhibitor of FAK; 5-methyl-4-[(1R,6R)-3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-1,3-benzenediol, selective GPR55 agonist; ALP; AM-251; AM-630; CB(1); CB(2); Cannabidiol; Cannabinoid receptors; Differentiation; FAK; G protein-coupled receptor 55; GPR55; JWH-133; LY-294.002; MAPK; MSCs; Mesenchymal stem cells; Migration; O-1602; O-1918; PD98059; PI3K; PKB; PP2; RT-PCR; Scr kinase; TRPV1; WST-1; [(6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl) (4-methoxyphenyl)methanone], selective CB(2) receptor antagonist; [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide], selective CB(1) receptor antagonist; alkaline phosphatase; cannabinoid receptor 1; cannabinoid receptor 2; focal adhesion kinase; mesenchymal stem cells; mitogen-activated protein kinase; phosphatidylinositol 3-kinase; protein kinase B/Akt; reverse transcriptase-polymerase chain reaction; sarcoma kinase; transient receptor potential vanilloid 1.
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