Human CD1c+ DCs are critical cellular mediators of immune responses induced by immunogenic cell death

Chemotherapeutics, including the platinum compounds oxaliplatin (OXP) and cisplatin (CDDP), are standard care of treatment for cancer. Although chemotherapy has long been considered immunosuppressive, evidence now suggests that certain cytotoxic agents can efficiently stimulate antitumor responses, through the induction of a form of apoptosis, called immunogenic cell death (ICD). ICD is characterized by exposure of calreticulin and heat shock proteins (HSPs), secretion of ATP and release of high-mobility group box 1 (HMGB1). Proper activation of the immune system relies on the integration of these signals by dendritic cells (DCs). Studies on the crucial role of DCs, in the context of ICD, have been performed using mouse models or human in vitro-generated monocyte-derived DCs (moDCs), which do not fully recapitulate the in vivo situation. Here, we explore the effect of platinum-induced ICD on phenotype and function of human blood circulating DCs. Tumor cells were treated with OXP or CDDP and induction of ICD was investigated. We show that both platinum drugs triggered translocation of calreticulin and HSP70, as well as the release of ATP and HMGB1. Platinum treatment increased phagocytosis of tumor fragments by human blood DCs and enhanced phenotypic maturation of blood myeloid and plasmacytoid DCs. Moreover, upon interaction with platinum-treated tumor cells, CD1c+ DCs efficiently stimulated allogeneic proliferation of T lymphocytes. Together, our observations indicate that platinum-treated tumor cells may exert an active stimulatory effect on human blood DCs. In particular, these data suggest that CD1c+ DCs are critical mediators of immune responses induced by ICD

Transcriptome signatures in Helicobacter pylori-infected mucosa identifies acidic mammalian chitinase loss as a corpus atrophy marker.

BACKGROUND: The majority of gastric cancer cases are believed to be caused by chronic infection with the bacterium Helicobacter pylori, and atrophic corpus gastritis is a predisposing condition to gastric cancer development. We aimed to increase understanding of the molecular details of atrophy by performing a global transcriptome analysis of stomach tissue. METHODS: Biopsies from patients with different stages of H. pylori infection were taken from both the antrum and corpus mucosa and analyzed on microarrays. The stages included patients without current H. pylori infection, H. pylori-infected without corpus atrophy and patients with current or past H. pylori-infection with corpus-predominant atrophic gastritis. RESULTS: Using clustering and integrated analysis, we found firm evidence for antralization of the corpus mucosa of atrophy patients. This antralization harbored gain of gastrin expression, as well as loss of expression of corpus-related genes, such as genes associated with acid production, energy metabolism and blood clotting. The analyses provided detailed molecular evidence for simultaneous intestinal metaplasia (IM) and spasmolytic polypeptide expressing metaplasia (SPEM) in atrophic corpus tissue. Finally, acidic mammalian chitinase, a chitin-degrading enzyme produced by chief cells, was shown to be strongly down-regulated in corpus atrophy. CONCLUSIONS: Transcriptome analysis revealed several gene groups which are related to development of corpus atrophy, some of which were increased also in H. pylori-infected non-atrophic patients. Furthermore, loss of acidic chitinase expression is a promising marker for corpus atrophy

Tetraspanin protein expression on DC subsets.

<p>Tetraspanin protein expression on DC subsets.</p

Protein expression of tetraspanins on human DC subsets.

<p>(A) Flow cytometric analysis of total tetraspanin protein expression on fixed permeabilized DC subsets. Far left: dot plots of viable Lin-MHC II+ cells. CD1c+ DCs were identified as BDCA1+, CD141+ DCs as BDCA3+, and pDCs as BDCA4+ cells. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s005" target="_blank">S2 Fig</a> for full gating strategy. Histograms of tetraspanin expression (black curve) and isotype control staining (grey curve) on gated cells depicted in the dot plots. (B) Tetraspanin expression of 3 healthy donors, geometric mean fluorescence intensity (gMFI) normalized for isotype control binding, each symbol represents one donor. P-values displayed above each plot represent the result of ANOVA to which multiple testing correction was been applied (n.s. = non-significant). * p<0.05, ** p< 0.01 ***p<0.001 by post-hoc t-testing. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s002" target="_blank">S2 Table</a> for full results of the statistical analysis.</p

Relative mRNA expression levels of tetraspanins in murine DC subsets.

<p>Z-scored values of (A) differentially expressed genes (ANOVA p<0.05) and (B) non-differentially expressed genes (ANOVA p>0.05 and expression > 2⁵ in at least two mice in one subset). Asterisks mark genes that were selected for further analysis. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s001" target="_blank">S1 Table</a> for selected probes and statistics on expression data of all members of the tetraspanin family. (C) Gene expression levels of tetraspanins in DC subsets, probe intensities are plotted, each symbol represents one mouse. P-values displayed above each plot represent the result of ANOVA to which multiple testing correction was been applied (n.s. = non-significant). * p<0.05, ** p< 0.01 ***p<0.001 by post-hoc t-testing. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s001" target="_blank">S1 Table</a> for full results of the statistical analysis.</p

Protein expression of tetraspanins on murine DC subsets.

<p>(A) Flow cytometric analysis of total tetraspanin protein expression on DC subsets. Cells from spleen were enriched for DCs as described in the materials and methods. Far left: dot plots of viable CD11c+ cells (CD4+ and CD8α+ DCs) or viable pDCs. CD4+ DCs were identified as CD4+CD11b+, CD8α+ DCs as CD8α+CD11b-, and pDCs as B220+CD11c^int cells. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s006" target="_blank">S3 Fig</a> for full gating strategy. Histograms of tetraspanin protein expression on gated cells depicted in the dot plots (black line) and isotype controls (grey line). (B) Average tetraspanin expression of 3 individual mice, geometric mean fluorescence intensity (gMFI) normalized for isotype control binding, each symbol represents one mouse. P-values displayed above each plot represent the result of ANOVA to which multiple testing correction was been applied (n.s. = non-significant). * p<0.05, ** p< 0.01 ***p<0.001 by post-hoc t-testing. See also <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184317#pone.0184317.s002" target="_blank">S2 Table</a> for full results of the statistical analysis.</p

Differential expression of tetraspanin superfamily members in dendritic cell subsets

textabstractDendritic cells (DCs), which are essential for initiating immune responses, are comprised of different subsets. Tetraspanins organize dendritic cell membranes by facilitating protein-protein interactions within the so called tetraspanin web. In this study we analyzed expression of the complete tetraspanin superfamily in primary murine (CD4+, CD8+, pDC) and human DC subsets (CD1c+, CD141+, pDC) at the transcriptome and proteome level. Different RNA and protein expression profiles for the tetraspanin genes across human and murine DC subsets were identified. Although RNA expression levels of CD37 and CD82 were not significantly different between human DC subsets, CD9 RNA was highly expressed in pDCs, while CD9 protein expression was lower. This indicates that relative RNA and protein expression levels are not always in agreement. Both murine CD8α+ DCs and its regarded human counterpart, CD141+ DCs, displayed relatively high protein levels of CD81. CD53 protein was highly expressed on human pDCs in contrast to the relatively low protein expression of most other tetraspanins. This study demonstrates that tetraspanins are differentially expressed by human and murine DC subsets which provides a valuable resource that will aid the understanding of tetraspanin function in DC biology