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Lymphocyte Sequestration Through S1P Lyase Inhibition and Disruption of S1P Gradients
Susan R. Schwab,1
João P. Pereira,1
Mehrdad Matloubian,1
Ying Xu,1
Yong Huang,2
Jason G. Cyster1*
Abstract:
Lymphocyte egress from the thymus and from peripheral lymphoidorgans depends on sphingosine 1-phosphate (S1P) receptor-1 andis thought to occur in response to circulatory S1P. However,the existence of an S1P gradient between lymphoid organs andblood or lymph has not been established. To further define egressrequirements, we addressed why treatment with the food colorant2-acetyl-4-tetrahydroxybutylimidazole (THI) induces lymphopenia.We found that S1P abundance in lymphoid tissues of mice is normallylow but increases more than 100-fold after THI treatment andthat this treatment inhibits the S1P-degrading enzyme S1P lyase.We conclude that lymphocyte egress is mediated by S1P gradientsthat are established by S1P lyase activity and that the lyasemay represent a novel immunosuppressant drug target.
1 Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 941430414, USA. 2 Drug Studies Unit, Department of Biopharmaceutical Sciences, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 941430414, USA.
* To whom correspondence should be addressed. E-mail: cyster{at}itsa.ucsf.edu
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