Leflunomide inhibits transendothelial migration of peripheral blood mononuclear cells

Abstract

Objectives: To test whether the active metabolite of leflunomide (LEF-M), in addition to blocking the proliferation of activated lymphocytes by inhibiting dihydro-orotate dehydrogenase (DHODH), influences the transendothelial migration (TEM) of peripheral blood mononuclear cells (PBMC). Methods:In an in vitro model of PBMC transmigration through an endothelial cell (EC) barrier, PBMC were re-collected in three groups: cells not adherent to the EC, cells bound to, and cells which had migrated through, the EC layer. Experiments in which cells were pretreated with LEF-M (in the absence or in the presence of uridine) were compared with parallel experiments in the presence of medium alone. Results: Preincubation of EC with LEF-M led to a 36 (SEM 16)% reduction in PBMC TEM (p,0.05). Likewise, preincubation of PBMC induced a reduction in their TEM of 39 (9)% (p,0.005). Incubation of both PBMC and EC with LEF-M had an additive effect (mean reduction of 48 (6)%, p,0.005). Incubation of PBMC with LEF-M also decreased monocytic CD44 expression (p,0.005) and PBMC-hyaluronan binding (p,0.05). Incubation of cells with LEF-M and uridine in addition to LEF-M reversed the inhibition of migration, suggesting that the observed effects were due to DHODH inhibition. Fluorocytometric analysis of PBMC subsets within the migrated population showed a decrease of monocytes, but not of B or T cells, after LEF-M treatment. Conclusions: LEF-M reduces monocytic adhesion molecule expression and TEM and may thus interfere with monocyte and EC activities in RA. Thus, the clinical effects of leflunomide may, at least in part, be due to blocking cell traffic into the inflamed synovia.

Disruption of the interaction of T cells with antigen‐presenting cells by the active leflunomide metabolite teriflunomide: Involvement of impaired integrin activation and immunologic synapse formation

“…Also, inhibited activation of monocytic cells by A77 1726-treated T cells (34) may be related to altered integrin avidity. Our data showing a complex influence of teriflunomide on integrin function are consistent with recent data that show that this drug also interferes with leukocyte/endothelial interactions (35). This peculiar property, which is not shared by most other currently used immunosuppressive drugs, such as calcineurin inhibitors, might also be involved in the beneficial effects of malononitrilamides on chronic allograft rejection (5,36).…”

Anti-inflammatory effects of leflunomide in combination with methotrexate on co-culture of T lymphocytes and synovial macrophages from rheumatoid arthritis patients

“…10 25 Lef-M was found to influence the transendothelial migration of PBMC by inhibiting DHODH in treated RA patients (mainly monocytes). 11 Fluorocytometric analysis of PBMC subsets within the migrated population showed a decrease in monocytes, but not in B or T cells, after Lef-M treatment. Furthermore, incubation with Lef-M of the PBMC from RA patients also decreased other cell adhesion molecule activity, such as monocytic CD44 expression and PBMC-hyaluronan binding.…”

“…[8][9][10] Recently, Lef-M was found to influence the transendothelial migration of peripheral blood mononuclear cells (PBMC) and to decrease cell adhesion molecule activity, such as monocytic CD44 expression and PBMC-hyaluronan binding by inhibiting DHODH in treated RA patients. 11 All these effects might act together to block cell activation and cell traffic into inflamed RA synovial tissue.…”

The Active form of Leflunomide, HMR1726, Facilitates TNF-a and IL-17 Induced MMP-1 and MMP-3 Expression

“…Cutolo et al could demonstrate that the active metabolite of leflunomide, A771726, showed anti-inflammatory effects on LPS activated cultured macrophages derived from RA patients [21]. Grisar et al reported that only a high concentration of 100 µM A771726 inhibited the transendothelial migration of inflammatory cells by reducing adhesion and transmigratory capacity [22].…”