Cannabinoid receptor CB2 modulates the CXCL12/CXCR4-mediated chemotaxis of T lymphocytes

Cannabinoids have been shown to influence the immune system. However, their immunomodulatory effects have not been extensively studied. In this investigation, we have observed that both primary and Jurkat T cells express a functional cannabinoid receptor 2 (CB2). Furthermore, both the synthetic cannabinoids CP55,940 and WIN55,212-2, as well as the CB2-selective agonist JWH-015, caused a significant inhibition of the chemokine CXCL12-induced and CXCR4-mediated chemotaxis of Jurkat T cells, as well as their transendothelial migration. Involvement of the CB2 receptor was further confirmed by partial reversal of the inhibition using the CB2-specific antagonist, AM630. Similarly, CP55,940 and JWH-015 inhibited the CXCL12-induced chemotaxis of primary CD4+ and CD8+ T lymphocytes. Further investigation of signaling studies to delineate the mechanism of inhibition revealed that cannabinoids enhance CXCL12-induced p44/42 MAP kinase activity. However, enhanced MAP kinase activity was not responsible for the inhibition of chemotaxis. This suggests that cannabinoids differentially regulate CXCR4-mediated migration and MAP kinase activation in T cells. Cannabinoids were also found to downregulate the PMA-enhanced enzyme activity of matrix metalloproteinase-9, which is known to play an important role in transendothelial migration. This study provides novel information regarding cannabinoid modulation of functional effects in T cells.