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Upon T cell receptor stimulation, CD4(+) T helper (Th) lymphocytes release extracellular vesicles (EVs) containing microRNAs. However, no data are available on whether human CD4(+) T cell subsets release EVs containing different pattern of microRNAs. The present work aimed at filling this gap by assessing the microRNA content in EVs released upon in vitro T cell receptor stimulation of Th1, Th17, and T regulatory (Treg) cells. Our results indicate that EVs released by Treg cells are significantly different compared with those released by the other subsets. In particular, miR-146a-5p, miR-150-5p, and miR-21-5p are enriched, whereas miR-106a-5p, miR-155-5p, and miR-19a-3p are depleted in Treg-derived EVs. The in vitro identified EV-associated microRNA signature was increased in serum of autoimmune patients with psoriasis and returned to healthy levels upon effective treatment with etanercept, a biological drug targeting the TNF pathway and suppressing inflammation. Moreover, Gene Set Enrichment Analysis showed an over-representation of genes relevant for T cell activation, such as CD40L, IRAK1, IRAK2, STAT1, and c-Myb in the list of validated targets of Treg-derived EV miRNAs. At functional level, Treg-derived (but not Th1/Th17-derived) EVs inhibited CD4(+) T cell proliferation and suppressed two relevant targets of miR-146a-5p: STAT1 and IRAK2. In conclusion, our work identified the miRNAs specifically released by different human CD4(+) T cell subsets and started to unveil the potential use of their quantity in human serum to mark the pathological elicitation of these cells in vivo and their biological effect in cell to cell communication during the adaptive immune response.

Currently available clinico-pathologic criteria provide an imperfect assessment of outcome for patients with advanced epithelial ovarian cancer (EOC). Identification of prognostic factors related to tumor biology might improve this assessment. We investigated the prognostic significance of the melanoma cell adhesion molecule (M-CAM) in EOC. Using the same antibody, M-CAM expression was tested by Western blotting in protein extracts and by immunohistochemestry in tissue microarrays generated from 133 consecutively resected, well characterized EOC samples. Fisher test, Kaplan-Meier method and Cox proportional hazards analysis were used to relate M-CAM expression to clinico-pathological variables and to time to progression (TTP) and overall survival (OS). In vitro biochemical analysis showed a progressively increased M-CAM expression from normal to malignant cells. MCAM protein, detected immunohistochemically, was significantly associated with advanced tumor stage, serous and undifferentiated histotype, extent of residual disease and p53 accumulation. Presence or absence of M-CAM significantly divided patients according to their TTP (median, 22 vs. 79 months, respectively; log-rank p = 0.001) and OS (median, 42 vs. 131 months, respectively; log-rank p = 0.0003). In the subgroup of advanced stage patients who achieved complete response after front-line treatment, M-CAM expression and absence of residual disease were significantly associated with shorter TTP (p = 0.003, HR 5.25, 95% CI 1.79-15.41 and p = 0.011, HR 3.77, 95% CI 1.36-10.49 respectively) at the multivariate level. In the same sub-group of patients, M-CAM expression remained the only parameter significantly associated with OS (p = 0.005, HR 3.35, 95% CI 1.42-6.88). M-CAM is a marker of early relapse and poorer outcome in EOC. In particular, M-CAM expression identifies a subgroup of front-line therapy-responding patients who undergo dramatic relapses, thus helping to better select patients who might benefit from new/alternative therapeutic modalities. (c) 2006 Wiley-Liss, Inc. OI Demichelis, Francesca/0000-0002-8266-8631 ZR 0 ZS 0 ZB 38