Interleukin-10 signaling in regulatory T cells is required for suppression of Th17 cell-mediated inflammation.

Effector CD4+ T cell subsets, whose differentiation is facilitated by distinct cytokine cues, amplify the corresponding type of inflammatory response. Regulatory T (Treg) cells integrate environmental cues to suppress particular types of inflammation. In this regard, STAT3, a transcription factor essential for T helper 17 (Th17) cell differentiation, is necessary for Treg cell-mediated control of Th17 cell responses. Here, we showed that anti-inflammatory interleukin-10 (IL-10), and not proinflammatory IL-6 and IL-23 cytokine signaling, endowed Treg cells with the ability to suppress pathogenic Th17 cell responses. Ablation of the IL-10 receptor in Treg cells resulted in selective dysregulation of Th17 cell responses and colitis similar to that observed in mice harboring STAT3-deficient Treg cells. Thus, Treg cells limit Th17 cell inflammation by serving as principal amplifiers of negative regulatory circuits operating in immune effector cells.

Monocytes/macrophages and/or neutrophils are the target of IL-10 in the LPS endotoxemia model.

IL-10 is a potent regulator of the innate and adaptive immune responses. Several cell types produce IL-10 and its receptor chains and these may regulate different immune responses. Here we report that inactivation of the IL-10 receptor (IL-10R1) gene in mice leads to an increased susceptibility to chemically induced colitis as in the classical IL-10-deficient mutant. To identify the cells regulated by IL-10 in immune responses, we generated several cell type specific IL-10R1-deficient mutants. We show that, in an IL-10-dependent LPS model of endotoxemia, dampening of the immune response requires expression of IL-10R1 in monocytes/macrophages and/or neutrophils but not in T cells nor B cells. As the macrophage and/or neutrophil-specific IL-10-deficient mutants also display the same phenotype, our results suggest that an autocrine loop in monocytes/macrophages is the most probable mechanism for the regulation of an LPS-induced septic shock. In contrast, in an IL-10-regulated T-cell response to Trichuris muris infection, IL-10 acting on T cells or monocytes/macrophages/neutrophils is not critical for the control of the infection.

A MALDI MS investigation of the lysophosphatidylcholine/phosphatidylcholine ratio in human spermatozoa and erythrocytes as a useful fertility marker.

The human spermatozoa membrane is characterized by a unique fatty acyl composition with significant amounts of highly unsaturated fatty acids, particularly docosahexaenoic acid (22:6), whereby phosphatidylcholine (PtdCho) (16:0/22:6) is the most abundant glycerophospholipid. The large amount of highly unsaturated fatty acyl residues is crucial for the fluidity of the membrane and, therefore, the successful fertilization process. Consequently, however, the spermatozoa are very sensitive to reactive oxygen species (ROS) that are generated under conditions of "oxidative stress" and key players in many pathological conditions. Lipid oxidation of the sperm membrane is accompanied by the loss of the oxidatively modified unsaturated residue (normally in the sn-2 position) and the generation of saturated lysophosphatidylcholine (LysoPtdCho). Although other lysolipids are also generated, LysoPtdCho is the "marker" lipid of choice due to the high abundance of PtdCho. In particular, obesity (body mass index >30 kg/m(2)) is characterized by increased ROS generation and negatively affects the reproductive potential. We will show here that the LysoPtdCho/PtdCho ratio can be easily determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The data found do correlate with clinical markers of sperm quality. A very interesting aspect is that the LysoPtdCho/PtdCho ratios determined in the spermatozoa extracts correlate with the LysoPtdCho/PtdCho values determined in the organic extracts of erythrocytes. Thus, there is no absolute need for a sperm investigation, but an estimation of the fertilizing ability of the corresponding male could be also made directly from the blood which is more readily available than the spermatozoa.

Connected culture of murine hepatocytes and HUVEC in a multicompartmental bioreactor.

A multicompartmental bioreactor was conceived and designed to mimic cross talk between cells in different culture chambers connected only by flow, such that cell-cell interaction is mediated by soluble ligands as occurs in the body. The system was tested with a connected culture of murine hepatocytes and human umbilical vein endothelial cells. Metabolites such as albumin, urea, lactate and viability were monitored during the course of the experiments and compared with monoculture conditions in the bioreactor. When the two cell types are placed in connected culture, there is an increase in endothelial cell viability and hepatic glucose synthesis as well as albumin and urea production, while overall lactate production in the system is downregulated. The results show that the multicompartmental bioreactor enhances cell function, effectively combining both heterotypic interactions with increased nutrient availability.

Quantum dots for human mesenchymal stem cells labeling. A size-dependent autophagy activation.

Lately certain cytotoxicity of quantum dots (QDs) and some deleterious effects of labeling procedure on stem cells differentiation abilities were shown. In the present study we compared cytotoxicity and intracellular processing of two different-sized protein-conjugated QDs after labeling of the human mesenchymal stem cells (hMSC). An asymmetrical intracellular uptake of red (605 nm) and green (525 nm) quantum dots was observed. We describe for the first time a size-dependent activation of autophagy, caused by nanoparticles.