The cannabinoid receptors agonist WIN55212-2 inhibits macrophageal differentiation and alters expression and phosphorylation of cell cycle control proteins

Abstract

In this study we investigated if and how cannabinoid receptor stimulation regulates macrophageal differentiation, which is one of the key steps in the immune effector reaction. For that reason, we used a well established differentiation model system of human U937 myelocytic leukemia cells that differentiate along the monocyte/macrophage lineage upon stimulation with the phorbol ester PMA. Constant cannabinoid receptor (CB) stimulation was performed using WIN55212-2, a potent synthetic CB agonist. We found that WIN55212-2 inhibited CB1/2-receptor-dependent PMA-induced differentiation of human myelocytic U937 cells into the macrophageal phenotype, which was associated with impaired vimentin, ICAM-1 and CD11b expression. In the presence of WIN55212-2, cdc2 protein and mRNA expression was progressively enhanced and Tyr-15-phosporylation of cdc2 was reduced in differentiating U937 cells. Additionally, p21Waf1/Cip1 expression was up-regulated. PMA-induced apoptosis was not enhanced by WIN55212-2 and differentiation-associated c-jun expression was not altered. In conclusion, we suppose that WIN55212-2-induced signals interferes with cell-cycle-arrest-signaling in differentiating myelocytic cells and thus inhibits macrophageal differentiation. Thus, it is possible that the cannabinoid system is able to influence one of the key steps in the immune effector function, the monocytic-macrophageal differentiation by alteration of cell cycle control proteins cdc2 and p21, and is therefore representing a promising option for therapeutic intervention in exacerbated immune reactions.

Repeated social defeat-induced neuroinflammation, anxiety-like behavior and resistance to fear extinction were attenuated by the cannabinoid receptor agonist WIN55,212-2

“…For instance, CB 1 receptors modulate noradrenaline release from sympathetic neurons outside the brain [39]. Moreover, WIN may directly interfere with myeloid cells production and trafficking [40,41] and may prevent the differentiation of myeloid cells to a more adherent phenotype [42]. Thus, WIN can activate CB 1 receptors on noradrenergic terminals reducing sympathetic outflow to the bone marrow and can interfere with the traffic of myeloid cells.…”

Global analysis of alternative splicing in human cells of myeloid origin

“…Lastly, we did not observe any change in CD33 expression, a marker of myeloid lineage, which is highly expressed in all conditions (data not shown). Excluding some exceptions, these results confirm what is reported in the literature for the differentiation of monocytes to macrophages (Rogler et al, 1998, Daigneault et al, 2010Paulsen at al., 2011; Aldo et al, 2013).…”

Differentiation and cell density upregulate cytochrome c levels in megakaryoblastic cell lines: Implications for analysis of CYCS-associated thrombocytopenia

“…As PMA is known to induce differentiation of a range of cells we investigated whether PMA-induced upregulation of cytochrome c was specific to megakaryopoiesis or a general feature of PMA-induced differentiation. We analysed a second megakaryocytic cell line, MEG-01 [ 20 ], the U937 monocytic cell line in which PMA induces growth arrest and differentiation into adherent macrophage-like cells [ 21 , 22 ], and HeLa cells, which do not undergo differentiation ( Fig 2 ). Treatment with PMA induced MEG-01 cell differentiation ( S2 Fig ) and resulted in a 3–7 fold increase in cytochrome c expression, similar to that observed in SET-2 cells.…”