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Posttrauma Increased Thrombospondin-1 Production Contributes to Increased Sensitivity of T Cell to TRAIL-mediated Post-injury Apoptosis
S72 as well as with a combination of BAFF and IL-6, which also promoted B-cell survival (P b 0.001), CD86 expression (P b 0.01), and IgG secretion (P b 0.05). Astrocyte-exposed B cells exhibited significantly enhanced capacity to induce allogeneic T-cell proliferation (P b 0.001). B-cell IgG responses were synergistically increased upon further addition of IL-10 and IL-15 (P b 0.001), notably in the absence of either antigen or T-cell help. Finally, B cells activated through standard BCR/CD40 cross-linking in presence of the astrocyte factors BAFF, IL-6, and IL-15 secreted significantly more LTα (P b 0.05), a pro-inflammatory cytokine known to contribute to germinal-center formation. These results indicate that specific human astrocytic factors within the inflamed MS CNS can enhance local B-cell survival and disease-relevant B-cell responses, including T-cell activation, Ig production, and secretion of pro-inflammatory/lymphoneogenic cytokines. doi:10.1016/j.clim.2010.03.218
T.119. Posttrauma Increased Thrombospondin-1 Production Contributes to Increased Sensitivity of T Cell to TRAIL-mediated Post-injury Apoptosis Gautam Bandyopadhyay, Sanjukta Bandyopadhyay, Sreenath Kundimi, Paul Bankey, Carol Miller-Graziano. University of Rochester Medical Center, Rochester, NY Posttrauma increased T cells (Tc) apoptosis can lead to emergence of Pt Tc anergy and immunopathology. Surprisingly, elevated FAS-mediated Tc apoptosis correlates poorly to these postinjury Tc apoptosis increases. However, elevated caspase10 activation (typical of human TRAIL induced apoptosis) is readily detected in the Pt apoptotic Tc. Upon assessing the role of increased Pt Tc active caspase-10 in subsequent development of Pt Tc anergy [50% reduced proliferation/cytokine production to αCD3 alone and αCD3+αCD28], we found that all isolated Pt Tc showed slightly increased levels of caspase-10 versus control (Cnt) (Tc active caspase-10 expression: Cnt 2.39 ±0.23%; Pt 6.7 ±1.8%). However, only Pts with both significantly increased apo-Tc active caspase-10 (20.73± 5.7%) and elevated plasma TRAIL levels (89.3 ±9.4 pg/ml vs. Cnt 68.9± 4, or low apo-Tc Pts 70.9± 5.8) later developed Tc anergy. Those patients experiencing both elevated apo-Tc and plasma TRAIL levels also had increased monocyte (MO) thrombospondin-1 (TSP-1). TSP-1 is a CD47 ligand known to increase Fas-sensitivity in activated Tc. The median flow cytometric MFI of TSP-1 was 153.43 in Pt MO with high apo-Tc and elevated TRAIL vs 78.9 in low apo-Tc Pt MO and 71.42 in Cnt. We also found TSP-1-CD47 triggering of control αCD3-stimulated Tc increased their TRAIL apoptosis sensitivity. Combining TSP-1 peptide binding and TRAIL treatment of stimulated Tc increased caspase-10 activation (median 27.4%) compared to treating with TRAIL (median 6.5%) or TSP-1 peptide (median 7.4%) alone. These data suggest that elevated MO TSP-1 and plasma TRAIL levels combine to increased trauma Pts' TRAIL mediated Tc apoptosis presaging and contributing to their subsequent Tc anergy. doi:10.1016/j.clim.2010.03.219
Abstracts
T.120. Inflammation-induced Changes in Deaf1 Splicing Alter Peripheral Tissue Antigen Gene Expression in the Pancreatic Lymph Node during the Pathogenesis of Type I Diabetes Linda Yip, Remi Creusot, Leon Su, Charles Fathman. Stanford University, Stanford, CA Type 1 diabetes (T1D) is thought to result from a breakdown in peripheral tolerance, in part controlled by peripheral tissue antigen (PTA) expression in lymph node stromal cells (LNSCs). We demonstrate that, in the pancreatic lymph node (PLN), a transcriptional regulator, deformed epidermal autoregulatory factor 1 (Deaf1), controls the expression of genes encoding various pancreatic PTAs. In the non-obese diabetic (NOD) mouse model of T1D, we showed that Deaf1 expression was significantly decreased, while the expression of an alternatively spliced variant of Deaf1 (DF1VAR) was increased in the PLN at the onset of disease. Remarkably, we identified a functionally similar isoform of Deaf1 that was upregulated in the PLN of T1D patients. Both Deaf1 variants heterodimerize with and decrease the transcriptional activity of the canonical isoform of Deaf1. Upregulation of the variant Deaf1 isoform expression correlated with reduced expression of pancreatic PTAs in the PLN, but not spleen, of NOD mice and T1D patients. Within the PLN tissues, DF1-VAR1 expression was highest in LNSCs compared to T and B cells of 12-week-old NOD mice but was not detected in LNSCs of 12-week-old NOD.SCID mice, suggesting that the alternative splicing of Deaf1 was driven by inflammation in the PLN that occured during disease. Overall, these data suggest that the pathogenesis of NOD disease and T1D may involve the inflammation-induced splicing of Deaf1 selectively in the PLN that can result in reduced PTA expression and decreased peripheral tolerance. doi:10.1016/j.clim.2010.03.220
T.121. Collaborative Effects of IL-17 and IL-23 in Deletion of Antigen Stimulated CD4+CD8+ Double Positive Thymocytes Hao Li 1, Qi Wu 1, PingAr Yang 1, John Wang 1, Jay Kolls 2, Hui-Chen Hsu 1, John Mountz 1. 1University of Alabama at Birmingham, Birmingham, AL; 2Louisiana State University Health Sciences Center, New Orleans, LA Increased levels of IL-17 and IL-23 have been associated with autoimmunity, but the effects of these two cytokines on thymocyte selection have not been studied. To test this, we injected normal B6 mice with adenovirus that expresses either IL-17 (AdIL17) or IL-23 (AdIL-23).There was dramatic reduction of thymus cellularity and increased apoptosis of DP thymocytes in AdIL-23 but not AdIL-17 or control AdLacZ-injected mice. Coinjection of AdIL-17 potentiated the effects of AdIL-23. Blocking of IL-17 by coinjection of anti-IL-17 with AdIL-23 partially corrected the effects of AdIL-23 to deplete DP thymocytes. In AdIL-17-,but not AdIL-23- or AdLacZ-treated thymus, there was enhanced recruitment of CD11b+ and CD11c+ cells in the junction between cortex and medulla where they
T.119. Posttrauma Increased Thrombospondin-1 Production Contributes to Increased Sensitivity of T Cell to TRAIL-mediated Post-injury Apoptosis Gautam Bandyopadhyay, Sanjukta Bandyopadhyay, Sreenath Kundimi, Paul Bankey, Carol Miller-Graziano. University of Rochester Medical Center, Rochester, NY Posttrauma increased T cells (Tc) apoptosis can lead to emergence of Pt Tc anergy and immunopathology. Surprisingly, elevated FAS-mediated Tc apoptosis correlates poorly to these postinjury Tc apoptosis increases. However, elevated caspase10 activation (typical of human TRAIL induced apoptosis) is readily detected in the Pt apoptotic Tc. Upon assessing the role of increased Pt Tc active caspase-10 in subsequent development of Pt Tc anergy [50% reduced proliferation/cytokine production to αCD3 alone and αCD3+αCD28], we found that all isolated Pt Tc showed slightly increased levels of caspase-10 versus control (Cnt) (Tc active caspase-10 expression: Cnt 2.39 ±0.23%; Pt 6.7 ±1.8%). However, only Pts with both significantly increased apo-Tc active caspase-10 (20.73± 5.7%) and elevated plasma TRAIL levels (89.3 ±9.4 pg/ml vs. Cnt 68.9± 4, or low apo-Tc Pts 70.9± 5.8) later developed Tc anergy. Those patients experiencing both elevated apo-Tc and plasma TRAIL levels also had increased monocyte (MO) thrombospondin-1 (TSP-1). TSP-1 is a CD47 ligand known to increase Fas-sensitivity in activated Tc. The median flow cytometric MFI of TSP-1 was 153.43 in Pt MO with high apo-Tc and elevated TRAIL vs 78.9 in low apo-Tc Pt MO and 71.42 in Cnt. We also found TSP-1-CD47 triggering of control αCD3-stimulated Tc increased their TRAIL apoptosis sensitivity. Combining TSP-1 peptide binding and TRAIL treatment of stimulated Tc increased caspase-10 activation (median 27.4%) compared to treating with TRAIL (median 6.5%) or TSP-1 peptide (median 7.4%) alone. These data suggest that elevated MO TSP-1 and plasma TRAIL levels combine to increased trauma Pts' TRAIL mediated Tc apoptosis presaging and contributing to their subsequent Tc anergy. doi:10.1016/j.clim.2010.03.219
Abstracts
T.120. Inflammation-induced Changes in Deaf1 Splicing Alter Peripheral Tissue Antigen Gene Expression in the Pancreatic Lymph Node during the Pathogenesis of Type I Diabetes Linda Yip, Remi Creusot, Leon Su, Charles Fathman. Stanford University, Stanford, CA Type 1 diabetes (T1D) is thought to result from a breakdown in peripheral tolerance, in part controlled by peripheral tissue antigen (PTA) expression in lymph node stromal cells (LNSCs). We demonstrate that, in the pancreatic lymph node (PLN), a transcriptional regulator, deformed epidermal autoregulatory factor 1 (Deaf1), controls the expression of genes encoding various pancreatic PTAs. In the non-obese diabetic (NOD) mouse model of T1D, we showed that Deaf1 expression was significantly decreased, while the expression of an alternatively spliced variant of Deaf1 (DF1VAR) was increased in the PLN at the onset of disease. Remarkably, we identified a functionally similar isoform of Deaf1 that was upregulated in the PLN of T1D patients. Both Deaf1 variants heterodimerize with and decrease the transcriptional activity of the canonical isoform of Deaf1. Upregulation of the variant Deaf1 isoform expression correlated with reduced expression of pancreatic PTAs in the PLN, but not spleen, of NOD mice and T1D patients. Within the PLN tissues, DF1-VAR1 expression was highest in LNSCs compared to T and B cells of 12-week-old NOD mice but was not detected in LNSCs of 12-week-old NOD.SCID mice, suggesting that the alternative splicing of Deaf1 was driven by inflammation in the PLN that occured during disease. Overall, these data suggest that the pathogenesis of NOD disease and T1D may involve the inflammation-induced splicing of Deaf1 selectively in the PLN that can result in reduced PTA expression and decreased peripheral tolerance. doi:10.1016/j.clim.2010.03.220
T.121. Collaborative Effects of IL-17 and IL-23 in Deletion of Antigen Stimulated CD4+CD8+ Double Positive Thymocytes Hao Li 1, Qi Wu 1, PingAr Yang 1, John Wang 1, Jay Kolls 2, Hui-Chen Hsu 1, John Mountz 1. 1University of Alabama at Birmingham, Birmingham, AL; 2Louisiana State University Health Sciences Center, New Orleans, LA Increased levels of IL-17 and IL-23 have been associated with autoimmunity, but the effects of these two cytokines on thymocyte selection have not been studied. To test this, we injected normal B6 mice with adenovirus that expresses either IL-17 (AdIL17) or IL-23 (AdIL-23).There was dramatic reduction of thymus cellularity and increased apoptosis of DP thymocytes in AdIL-23 but not AdIL-17 or control AdLacZ-injected mice. Coinjection of AdIL-17 potentiated the effects of AdIL-23. Blocking of IL-17 by coinjection of anti-IL-17 with AdIL-23 partially corrected the effects of AdIL-23 to deplete DP thymocytes. In AdIL-17-,but not AdIL-23- or AdLacZ-treated thymus, there was enhanced recruitment of CD11b+ and CD11c+ cells in the junction between cortex and medulla where they