Oriana Rossi

Azienda Unità Sanitaria Locale 6 Livorno, Leghorn, Tuscany, Italy

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Publications (4)15.05 Total impact

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    ABSTRACT: In the intestinal mucosa, several adaptations of TLR signalling have evolved to avoid chronic inflammatory responses to the presence of commensal microbes. Here we investigated whether polarized monolayers of intestinal epithelial cells might regulate inflammatory responses by secreting IL-8 in a vectorial fashion (i.e. apical versus basolateral) depending on the location of the TLR stimulus. In the Caco-2 BBE model of polarized villus-like epithelium, apical stimulation with TLR2 and TLR5 ligands resulted in the apical secretion of IL-8. The CXCR1 receptor for IL-8 was expressed only on the apical membrane of Caco-2 BBE cells and differentiated epithelial cells in the human small intestine and colon. Transcriptome analyses revealed that Caco-2 BBE cells respond to stimulation with IL-8 supporting the hypothesis that IL-8 induces G protein-coupled receptor signalling. These results show that IL-8 induces autocrine signalling via an apical CXCR1 in Caco-2 BBE intestinal epithelial cells and that this receptor is also expressed on the apical surface of differentiated human intestinal epithelial cells in vivo, suggesting an autocrine function for IL-8 secreted in the lumen.
    BMC Research Notes 10/2013; 6(1):431.
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    ABSTRACT: To peacefully coexist with the microbial inhabitants of the intestine, mammals have evolved elaborate and interconnected regulatory mechanisms to maintain immune homeostasis in the face of potential infection and tissue damage by pathogenic microorganisms. Physical barriers, antimicrobial factors and secretory antibodies act in concert to keep microbes at a distance from the epithelium and initiate repair mechanisms in the event of damage. Commensal bacteria are not ignored but dynamically controlled via many complex overlapping and intertwined mechanisms involving intestinal epithelial cells (IECs) and signals from the microbiota. Polarized IECs play a decisive role in homeostasis by regulating the expression and activity of the pattern-recognition receptors (PRRs), in different compartments of the intestine. The differential signaling and expression of receptors on apical and basal membranes of the epithelium also plays its part in distinguishing commensals from harmful invaders. In steady state conditions macrophages and dendritic cells (DCs) in the lamina propria (LP) are conditioned by environmental factors to induce immune tolerance. The distinction between pathogen and non-pathogen is linked to the ability of pathogens to invade and cause damage to the host cells and tissues. This induces local inflammatory responses and the attraction of capillary leukocytes by chemokines released from colonized and invaded epithelial cells. This bypasses the tolerogenic mechanisms controlling the responses of resident DCs and macrophages leading to pathogen killing and adaptive immune responses. Research on this topic has important implications for the development of novel therapeutic approaches to treat or prevent inflammatory bowel disease (IBD), inflammation-related cancer and other gut-related diseases and disorders.
    Current topics in microbiology and immunology 12/2011; · 4.86 Impact Factor
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    ABSTRACT: This article provides an overview of how intestinal epithelial cells (IEC) recognize commensals and how they maintain host-bacterial symbiosis. Endocrine, goblet cells, and enterocytes of the intestinal epithelium express a range of pattern recognition receptors (PRR) to sense the presence of microbes. The best characterized are the Toll-like receptors (TLR) and nucleotide oligomerization domain-like receptors (NLR), which play a key role in pathogen recognition and the induction of innate effectors and inflammation. Several adaptations of PRR signaling have evolved in the gut to avoid uncontrolled and potentially destructive inflammatory responses toward the resident microbiota. PRR signaling in IEC serve to maintain the barrier functions of the epithelium, including the production of secretory IgA (sIgA). Additionally, IECs play a cardinal role in setting the immunosuppressive tone of the mucosa to inhibit overreaction against innocuous luminal antigens. This includes regulation of dendritic cells (DC), macrophage and lymphocyte functions by epithelial secreted cytokines. These immune mechanisms depend heavily on IEC recognition of microbes and are consistent with several studies in knockout mice that demonstrate TLR signaling in the epithelium has a profoundly beneficial role in maintaining homeostasis.
    Proceedings of the National Academy of Sciences 03/2011; 108 Suppl 1:4607-14. · 9.81 Impact Factor
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    ABSTRACT: For a few years now in Italy there has been wide discussion on the advisability of developing health surveillance programmes for workers who were exposed to occupational carcinogens in the past (incompliance with Italian D.Lgs. 626/94, art. No. 69). The purpose of the present paper was to contribute to the discussion on operative guidelines for public or private Occupational Health Services intending to address this issue. A cross-sectional survey was undertaken on former workers of a glass factory located in Leghorn, Italy. Six hundred and seventy-seven workers discharged in the period 1/1/1942 - 30/6/1992, with at least 1 year of service, resident in the area of Leghorn, were identified from the personnel records of the company and invited to medical examination at the local public Occupational Health Service. A structured questionnaire was developed in order to standardize the collection of occupational and health histories. 370 subjects were examined and for each of them occupational and health histories were collected. Occupational exposure to carcinogens in the factory in the last decades was reconstructed using the workers' occupational histories and the available plant records: 3 periods with different production activities (1942/49, 1950/69, 1970/92), and 4 main carcinogens (asbestos, PAH, silica and glass fibres) were identified. Thirty cancers were recorded and 10 of these were occupationally related. The health survey allowed occupational exposures to carcinogens to be defined in a factory where historical environmental data were not available. It was also possible to assess individual past occupational risk and provide information to each former worker on his risk, on available preventive measures, and on possible diagnostic, therapeutic and insurance procedures available in relation to diseases related to the different hazards. Via this survey it was also possible to identify and notify the Italian Institute of Insurance against Occupational Diseases and Accidents of 6 cases of bladder cancer, i.e., cancers with long survival that would be impossible to identify via current health data bases.
    La Medicina del lavoro 01/2004; 95(6):465-74. · 0.38 Impact Factor