Stefania Campana

NCR + ILC3 concentrate in human lung cancer and associate with intratumoral lymphoid structures

Tertiary lymphoid structures (TLSs) are a common finding in non-small cell lung cancer (NSCLC) and are predictors of favourable clinical outcome. Here we show that NCR(+) innate lymphoid cell (ILC)-3 are present in the lymphoid infiltrate of human NSCLC and are mainly localized at the edge of tumour-associated TLSs. This intra-tumoral lymphocyte subset is endowed with lymphoid tissue-inducing properties and, on activation, produces IL-22, TNF-α, IL-8 and IL-2, and activates endothelial cells. Tumour NCR(+)ILC3 may interact with both lung tumour cells and tumour-associated fibroblasts, resulting in the release of cytokines primarily on engagement of the NKp44-activating receptor. In patients, NCR(+)ILC3 are present in significantly higher amounts in stage I/II NSCLC than in more advanced tumour stages and their presence correlate with the density of intratumoral TLSs. Our results indicate that NCR(+)ILC3 accumulate in human NSCLC tissue and might contribute to the formation of protective tumour-associated TLSs.

Cross-dressing: an alternative mechanism for antigen presentation.

Cross-dressing involves the transfer of preformed functional peptide-MHC complexes from the surface of donor cells to recipient cells, such as dendritic cells (DCs). These cross-dressed cells might eventually present the intact, unprocessed peptide-MHC complexes to T lymphocytes. In this review we will discuss some recent findings concerning the intercellular transfer of preformed MHC complexes and the possible mechanisms by which the transfer may occur. We will report evidences showing that both MHC class I and MHC class II functional complexes might be transferred, highlighting the physiological relevance of these cross-dressed cells for the presentation of exogenous antigens to both cytotoxic and helper T lymphocytes.

Natural killer cells in the innate immunity network of atherosclerosis.

Natural killer (NK) cells are innate lymphocytes which have recently been proposed to play an immunoregulatory role in the pathogenesis and progression of atherosclerosis. Although several studies have evaluated the frequency and the functions of NK cells both in human and in experimental animal models of atherosclerosis, it is yet not clear whether NK cells might behave as protective or pro-atherogenic effectors. Here, we review current knowledge regarding the role of NK cells in atherosclerosis and discuss the potential interactions that might occur in atherosclerotic lesions between NK cells and antigen presenting cells, such as macrophages and dendritic cells. A clearer depiction of the innate immune cell network operating in atherosclerosis might pave the way to novel interesting approaches for the prevention and treatment of this disease.

The Yin and Yang of Innate Lymphoid Cells in Cancer

The recent appreciation of novel subsets of innate lymphoid cells (ILCs) as important regulators of tissue homeostasis, inflammation and repair, raise questions regarding the presence and role of these cells in cancer tissues. In addition to natural killer and fetal lymphoid tissue inducer (LTi) cells, the ILC family comprises non-cytolytic, cytokine-producing cells that are classified into ILC1, ILC2 and ILC3 based on phenotypic and functional characteristics. Differently from natural killer cells, which are the prototypical members of ILC1 and whose role in tumors is better established, the involvement of other ILC subsets in cancer progression or resistance is still fuzzy and in several instances controversial, since current studies indicate both context-dependent beneficial or pathogenic effects. Here, we review the current knowledge regarding the involvement of these novel ILC subsets in the context of tumor immunology, highlighting how ILC subsets might behave either as friends or foes.

Divergent signaling pathways regulate IL-12 production induced by different species of Lactobacilli in human dendritic cells.

Recent studies have indicated that different strains of Lactobacilli differ in their ability to regulate IL-12 production by dendritic cells (DCs), as some strains are stronger inducer of IL-12 while other are not and can even inhibit IL-12 production stimulated by IL-12-inducer Lactobacilli. In this report we demonstrate that Lactobacillus reuteri 5289, as previously described for other strains of L. reuteri, can inhibit DC production of IL-12 induced by Lactobacilllus acidophilus NCFM. Remarkably, L. reuteri 5289 was able to inhibit IL-12 production induced not only by Lactobacilli, as so far reported, but also by bacteria of different genera, including pathogens. We investigated in human DCs the signal transduction pathways involved in the inhibition of IL-12 production induced by L. reuteri 5289, showing that this potential anti-inflammatory activity, which is also accompanied by an elevated IL-10 production, is associated to a prolonged phosphorilation of ERK1/2 MAP kinase pathway. Improved understanding of the immune regulatory mechanisms exerted by Lactobacilli is crucial for a more precise employment of these commensal bacteria as probiotics in human immune-mediated pathologies, such as allergies or inflammatory bowel diseases.

6-Mer Hyaluronan Oligosaccharides Modulate Neuroinflammation and .ALPHA.-Synuclein Expression in Neuron-Like SH-SY5Y Cells

Several studies have shown the degradation of the extracellular matrix at the site of neuroinflammation and increased release of degradation products of glycosaminoglycans. Among these, low molecular weight fragments of hyaluronan (HA) may play a key role in the events leading to neuroinflammation and/or neuronal degeneration. Small HA fragments are able to induce inflammation by stimulating both TLR‐2 and TLR‐4 as well as CD44 receptors. This stimulation culminates in the nuclear translocation of NF‐kB that in turn induces the production of pro‐inflammatory intermediates such as TNF‐α and IL‐1β. The potential of HA fragments, as mediators of inflammation, it has been poorly investigated in neuron‐like SH‐SY5Y cells so the aim of this study was to investigate the neuroinflammatory effects of very small HA oligosaccharides, the involvement of TLR‐2, TLR‐4, and CD44 and the production of α‐synuclein in such cells. The addition of HA fragments to cell cultures up‐regulated TLR‐2, TLR‐4, and CD44 levels, induced NF‐kB activity and increased both TNF‐α and IL‐β as well as α‐synuclein production. On blocking the activity of TLR‐2, TLR‐4, and CD44 the levels of inflammatory parameters and of α‐synuclein were significantly reduced. Since several data have shown as α‐synuclein, produced from neurons, is able to initiate ex novo or to maintain an existing neuroinflammatory response, which has been suggested as one of the principal components involved in neurodegenerative pathologies, as PD, we suggest that HA pathways should be given careful consideration when devising future anti‐neuroinflammatory strategies to defend against the onset of neurodegenerative disorders. J. Cell. Biochem. 117: 2835–2843, 2016.

T cell polarizing properties of probiotic bacteria

Different commensal bacteria employed as probiotics have been shown to be endowed with immunomodulatory properties and to actively interact with antigen presenting cells, such as dendritic cells and macrophages. In particular, different strains of probiotic bacteria may induce the secretion of a discrete cytokine profile able to induce divergent T cell polarization. Here, we briefly review current knowledge regarding the effects of different species and strains of probiotic bacteria on T cell polarization. Given that the loss of intestinal homeostasis is frequently associated with an aberrant T cell polarization profile, a comprehensive knowledge of the immunomodulatory potential of these bacteria is crucial for their employment in the management of human immune-mediated pathologies, such as allergies or inflammatory bowel diseases.

Th17 skewing in the GALT of a Crohn disease patient upon Lactobacillus rhamnosus GG consumption.

We wish to report on a recent observation we made and that ight represent a useful hint for the employment of the so called robiotics in the management of some pathological immune reacions of the gut. Probiotics have been defined as “live microorganisms, which, hen administered in adequate amounts, confer a health benefit n the host” (FAO/WHO, 2002) [1]. Currently, there is a cerain consensus that probiotic bacteria can help in the relief of ymptoms associated to several human diseases, including some mmunopathologies such as atopic diseases and inflammatory owel diseases (IBD), chronic infections [2], neoplasms and they ave even been proposed to play a role in the complex immune etwork underlying atherogenesis [3,4]. The beneficial effects of robiotics, which are usually administered per os, have been scribed to different factors: help in the absorption of otherwise ndigestible nutrients, especially complex carbohydrates; release f anti-inflammatory soluble factors; production of antimicrobial ubstances; competition for adhesion, sites and nutrients with athogenic bacteria; stimulation of the immune system [5]. In paricular, this last mechanism, i.e. the immunomodulatory activity of robiotics, has been widely investigated and different commensal acteria, which are usually administered as probiotics, have been hown to possess relevant properties, such as the ability to finely olarize both the innate and the adaptive immune response [5]. hese commensal bacteria should mainly exert direct effects on ntigen presenting cells such as dendritic cells (DCs), monocytes, acrophages, and, to a minor extent, B-cells, without necessarily eing the source of antigen. In vitro, different strains of commenal bacteria possess the ability to induce a discrete production of ytokines by myeloid DCs, which in turn would differently polarze the subsequent adaptive immune response toward specific T elper (Th) cell subsets (Th1, Th2, Th17) or even T regulatory cells 6–8]. These observations, especially the ability to polarize T cell esponse, support probiotics as interesting candidates in the treatent of immune-mediated pathologies, such as allergies and Crohn isease (CD), characterized by a disruption of the Th balance and n excess of, respectively, Th2 or Th1 immune response. Despite these interesting observations, the usefulness of probitics administration in these illnesses is often argued on the basis of lack of evidence that, upon their consumption, commensal bacteia passing through the gut, apparently without colonizing it, could stablish close interactions with local antigen presenting cells or ther immune cells. As a matter of fact, a main obstacle to these ontacts is supposed to be represented by the mucus layer in the ntestinal lumen.

Changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise

Serotonin (5-HT) is a neurohormone transported from plasma into platelets and leukocytes by a specific transporter (SERT). While it is known that the brain 5-HT system is modulated by physical exercise, the peripheral serotoninergic response to exercise is not yet fully elucidated. In particular, this study aimed to evaluate changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise in untrained horses. Analyses were carried out pre- and post-treadmill exercise. 5-HT plasma levels were analysed by HPLC. Leukocytes and platelets were isolated to perform Real Time PCR for the evaluation of SERT mRNA levels. Western blot was conducted for the detection of SERT protein levels. The presence of SERT in leukocytes was analysed by flow cytometry. The functionality of SERT on leukocytes was investigated by using paroxetine as inhibitor of 5-HT reuptake. Results showed a significant decrease in SERT levels after exercise in both leukocytes and platelets and a significant increase in plasma 5-HT levels. Flow cytometry revealed that SERT is functional in one specific horse leukocyte subpopulation, still not identified, and paroxetine was able to block 5-HT reuptake into leukocytes. The exercise may have induced an increased mobilization of free-tryptophan and a release of 5-HT from the stores in the blood. High concentrations of plasma 5-HT could have caused a reduction in SERT expression affecting cellular 5-HT storage/uptake. The increase of cortisol levels after treadmill exercise was not significant. Exercise modulates the peripheral serotonin metabolism. More research is needed to assess its physiological implications.