Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Dipyridamole Inhibits SLE T Cell Activation and Alleviates Nephritis in Lupus-Prone Mice.
Kyttaris, Vasileios C., Zhang, Zheng, Kampagianni, Ourania, Tsokos, George C.
SLE T cells provide help to B cells to produce autoantibodies and infiltrate tissues orchestrating local inflammatory responses. We have previously shown that SLE T cells are characterized by a robust calcineurin-mediated dephosphorylation of the transcription factor NFAT. Dephosphorylated (activated) NFAT tranlsocates to the nucleus and activates a host of genes, including the co-stimulatory molecule CD154 that enhances antibody production by B cells, and several pro-inflammatory cytokines.
NFAT/calcineurin inhibition represents an attractive option for the treatment of various inflammatory diseases. Yet calcineurin inhibitors (cyclosporine A, tacrolimus) have significant side effects including nephrotoxicity. It was shown recently that dipyridamole inhibits the activation of NFAT without affecting total calcineurin phosphatase activity, potentially causing fewer side effects.
T and B cells were isolated from the peripheral blood of patients with SLE and healthy individuals. The cells were incubated in the presence of dipyridamole (20mM or 50mM), or tartaric acid as control. T cells were activated with anti-CD3 and anti-CD28 antibodies. MRL/lpr lupus-prone mice were injected intraperitoneally with dipyridamole 50 mg/kg three times a week for 4 weeks. CD154 and cytokine production was measured with flowcytometry.
Dipyridamole treatment of SLE T cells inhibited NFAT activation and decreased the expression of CD154 by 66±21% (p<0.0001, N=9). The production of IFN-g decreased by 96±3% (p<0.0001, N=9), that of IL-17 by 74±29% (p<0.0001, N=9), and of IL-6 by 57±22% (p<0.0001, N=9). Moreover, dipyridamole inhibited the T cell directed production of immunoglobulin, including anti-dsDNA antibodies, in T:B cell mixed cultures. Activation of isolated B cells by anti-IgM was not affected by dipyridamole. Dipyridamole decreased significantly the expansion of T cells in vitro as assessed by CFSE staining.
Next, we treated MRL/lpr mice with dipyridamole. MRL/lpr mice have a very large number of CD3+CD4-CD8- T cells (double negative T cells, DNT) that express high levels of NFAT. Treatment of these mice with dipyridamole decreased proteinuria by 33% and prevented the emergence of pyuria. The dipyridamole treated mice did not develop skin lesions and were protected from early death (3/5 control-treated mice died by the fourth week of the trial as opposed to 0/5 in the dipyridamole treated group).
Dipyridamole treatment decreased the concentration of IL-6 in the serum (dipyridamole vs. control treated mice=364±52 vs. 5,280±206 pg/mL, p<0.0001). The percentage of CD3+ cells in the spleen decreased in the dipyridamole treated animals, primarily due to a decrease in DNT subpopulation (splenic DNT cells in dipyridamole vs. control treated mice= 47±2% vs. 67±4%, p=0.0045).
Inhibition of NFAT with dipyridamole results in decreased activation and expansion of lupus T cells, blocking at the same time T cell directed autoantibody production. Dipyridamole alleviates nephritis and prolongs survival of lupus-prone mice. Therefore we propose that dipyridamole is an attractive NFAT inhibitor that can be used in the treatment of SLE.
To cite this abstract, please use the following information:
Kyttaris, Vasileios C., Zhang, Zheng, Kampagianni, Ourania, Tsokos, George C.; Dipyridamole Inhibits SLE T Cell Activation and Alleviates Nephritis in Lupus-Prone Mice. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2126