Moreover, the effect of T cell–derived MPs on the activation of fibrogenic effector cells of a major organ such as the liver, where lymphocyte-driven inflammation frequently

occurs, has not been addressed.1 Finally, such MPs were not demonstrated in the circulation. We report that T cell MPs circulate in blood and are elevated in patients with Kinase Inhibitor Library high throughput active chronic hepatitis C. Further, MPs derived both from CD8+ and CD4+ T cells can induce a fibrolytic phenotype in HSCs. This activity depends on fusion of the MPs with HSC membranes and transfer of T cell membrane molecules such as CD147 (Emmprin) to HSCs in a partly CD54 (intercellular adhesion molecule 1 [ICAM-1])-dependent manner. We conclude that T cell MPs may become a novel diagnostic tool and could be used therapeutically to mitigate (hepatic) inflammation and fibrosis. ALT, alanine aminotransferase; ERK1/2, extracellular signal-regulated kinases 1 and 2; FACS, fluorescence-activated cell sorting; FBS, fetal bovine serum; HSC, hepatic stellate cell; ICAM-1, intercellular adhesion

molecule 1; IgG, immunoglobulin G; MMP, matrix metalloprotease; MP, microparticle; mRNA, messenger RNA; NFκB, nuclear factor kappa B; PHA, phytohemagglutinin; RT-PCR, reverse-transcription polymerase chain reaction; ST, staurosporine; TGFβ1, transforming growth factor β; TIMP-1, tissue inhibitor of metalloproteinase 1; TNFα, tumor necrosis factor α. Jurkat see more T cells (ATCC#: CRL-2570, Manassas, VA) were grown in 10% fetal bovine serum (FBS) in Roswell Park Memorial Institute 1640 medium, and LX-2 were grown in 2.5% FBS in Dulbecco’s modified Eagle’s medium (Cellgrow, Manassas, VA). THP-1 monocytes (American Type 上海皓元医药股份有限公司 Culture Collection No. TIB-202) were grown in 10% FBS in Dulbecco’s modified Eagle’s medium

(Cellgrow) and were differentiated into macrophages by way of incubation with 0.05 μg/mL phorbol myristate acetate for 24 hours.9 Human peripheral blood was collected in heparinized tubes from healthy volunteers within a protocol approved by Children’s Hospital (Boston, MA). Mononuclear cells were isolated by way of centrifugation over Ficoll-Paque Premium (GE Healthcare, Uppsala, Sweden). After three washes in Hank’s balanced salt solution, CD4+ and CD8+ T cells were isolated by way of negative selection using magnetic beads (Miltenyi Biotec, Auburn, CA). For induction of apoptosis, T cells or monocytes/macrophages were treated with 4 μmol/mL staurosporine (ST) (Cell Signaling Technology, Danvers, MA) for 4 hours. T cells were activated with 5 μg/mL phytohemagglutinin (PHA) (Roche, Mannheim, Germany) for 24 hours, and 3 days later restimulated. During stimulation with PHA, T cell cultures were supplemented with 5 ng/mL interleukin-2 (PeproTech, Rocky Hill, NJ).