Grammatikos, Alexandros P.Ghosh, DebjaniDevlin, AmyKyttaris, VasileiosTsokos, George2014-03-102013Grammatikos, Alexandros P., Debjani Ghosh, Amy Devlin, Vasileios C. Kyttaris, and George C. Tsokos. 2013. “Spleen Tyrosine Kinase (Syk) Regulates Systemic Lupus Erythematosus (SLE) T Cell Signaling.” PLoS ONE 8 (8): e74550. doi:10.1371/journal.pone.0074550. http://dx.doi.org/10.1371/journal.pone.0074550.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:11877106Engagement of the CD3/T cell receptor complex in systemic lupus erythematosus (SLE) T cells involves Syk rather than the zeta-associated protein. Because Syk is being considered as a therapeutic target we asked whether Syk is central to the multiple aberrantly modulated molecules in SLE T cells. Using a gene expression array, we demonstrate that forced expression of Syk in normal T cells reproduces most of the aberrantly expressed molecules whereas silencing of Syk in SLE T cells normalizes the expression of most abnormally expressed molecules. Protein along with gene expression modulation for select molecules was confirmed. Specifically, levels of cytokine IL-21, cell surface receptor CD44, and intracellular molecules PP2A and OAS2 increased following Syk overexpression in normal T cells and decreased after Syk silencing in SLE T cells. Our results demonstrate that levels of Syk affect the expression of a number of enzymes, cytokines and receptors that play a key role in the development of disease pathogenesis in SLE and provide support for therapeutic targeting in SLE patients.en-USJournal Article2014-03-1010.1371/journal.pone.0074550