register interest

Francesco Boccellato

Research Area: Cell and Molecular Biology
Technology Exchange: Cellular immunology, Immunohistochemistry, In situ hybridisation, Microscopy (Confocal), Microscopy (EM), Microscopy (Video) and Transcript profiling
Scientific Themes: Immunology & Infectious Disease and Cancer Biology

Background

The stomach mucosa is a barrier whose main function is to secrete acid and digestive enzymes and absorb the nutrients from the food. This barrier has also a fundamental protective role: it senses and reacts to bacterial infection. Helicobacter pylori is the only bacterium that can infect the stomach and its extraordinary ability to colonize the mucosa despite the strongly acidic environment has been associated with gastritis, stomach ulcers and with the onset of stomach cancer. The World Health Organization (WHO) considers Helicobacter pylori a class 1 carcinogen and stomach cancer cause more than 700,000 deaths per year worldwide. Thanks to higher hygiene standards that reduce the risk of bacterial transmission and to a more efficient diagnosis and treatment with antibiotics, the number of cases are diminishing, especially in the UK. Unfortunately, after 20 years of standard antibiotic therapies, the WHO has recognized that there is an alarming increase in the number of antibiotic-resistant cases.

The most external part of the stomach mucosa is the epithelium, which forms a continuous layer of cells that faces the lumen of the stomach. The mucosa is organized in narrow cavities called gastric glands. The glands are where H. pylori survives lifelong if not eradicated. In recent years, an increased understanding of stem cell biology has driven the development of organoid cultures as a way of maintaining adult stem cells in vitro, including those obtained by isolating glands from gastric tissue samples. Following the infection route of H.pylori, the pathogen would first cope with the mucus and then contact the apical side of the epithelium. Unfortunately, the organoids have their apical side located intraluminal and the mucus is scarcely accessible. Although organoids can be injected with bacteria to model infection in vitro, this system does not support neither large-scale infections nor analysis of the mucus. A system that enables routine infection while maintaining the epithelial architecture characterized by polarized cells and tight junctions, as well as an intact mucus layer, may thus support large-scale experiments, longer-term infection, and analysis of the mucus. We have recently harnessed air-liquid interface (ALI) methodology to establish functional, long-lived, epithelial polarized monolayers from healthy human stomachs, which fully recapitulate the different cell lineages found in situ, and accumulate mucins on the apical side (Boccellato et al., GUT, 2018).  We named these in-vitro models “mucosoid cultures”. The apical surface of the mucosoids is protected by secreted mucus, enabling chronic in vitro infection. These features represent key advantages over existing culture methods and permit advanced studies on the mechanisms of chronic inflammation, the role of mucus in epithelial defence, and the factors that control epithelial homeostasis during infection. As such, mucosoids represent an important and unique new tool for illuminating the mechanisms underlying gastrointestinal immunity and carcinogenesis 

Our programme:

How epithelial cells sense bacteria?

As the epithelial cells are the first to get in contact with foodborne bacteria or pathogens transmitted from faeces to mouth, they are equipped with surface sensors that are able to sense different bacterial molecules present on its surface (bacterial wall). Although H. pylori has these molecules on its surface, the epithelial cells are poorly sensitive to them. It is still unknown how the epithelium senses H. pylori and we aim to find new bacterially derived molecules and the corresponding epithelial receptors that mediate the sensing mechanisms. These mechanisms are general alarms for the presence of pathogens. We are interested in investigating  how activation of these sensors alerts the immune system and enhances the regeneration of the mucosa damaged by infection

What are the mechanisms of epithelial defence?

The gastrointestinal mucosa has evolved diverse mechanisms to prevent microbial infections. The epithelium secretes mucins on its apical side along with other proteins, which might have a role in regulating bacterial homeostasis. This protein aggregation represents a potent physical and chemical barrier to pathogenic invasion. Upon infection, the epithelium regulates the expression of anti-microbial peptides (AMPs) but pathogens including H.pylori have developed a remarkable ability to escape the mucosal immune defence, which appears to be intrinsically connected with a chronic inflammatory status. Regulation of the secretion of AMPs in the mucus is still poorly understood due to the lack of in-vitro mucus-producing epithelial models. We are interested in understanding the mechanism of antimicrobial secretion in the mucus and their role in controlling infections using our mucosoids model.  

How bacterial infection causes cancer?

To figure causal relationships between an infection and cancer onset is difficult, mainly because of the long-time span between the two events. Stronger connections to cancers might be delineated by understanding the regenerative capacity of gastric stem cells upon infection. If cancer arises at the site of infection, the cancer cell should derive from an infected cell with regenerative capacity. We are developing tools to distinguish differentiated vs non-differentiated cells by fluorescent markers and we are in addition developing methods to trace in vitro and in vivo the fate of the infected cells.

Name Department Institution Country
Xin Lu Oxford Ludwig Institute Oxford University, Old Road Campus Research Building United Kingdom
Pedro Moura Alves Oxford Ludwig Institute Oxford University, NDM Research Building United Kingdom
Colin Goding Oxford Ludwig Institute Oxford University, Old Road Campus Research Building United Kingdom
Thomas Meyer Max Planck Infection Biology Berlin Germany
Henri-Jacques Delecluse German Cancer Research Center Germany
Rolf Mueller Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) Germany
Posselt G, Wiesauer M, Chichirau BE, Engler D, Krisch LM, Gadermaier G, Briza P, Schneider S, Boccellato F, Meyer TF et al. 2019. Helicobacter pylori-controlled c-Abl localization promotes cell migration and limits apoptosis. Cell Commun Signal, 17 (1), pp. 10. | Show Abstract | Read more

BACKGROUND: Deregulated c-Abl activity has been intensively studied in a variety of solid tumors and leukemia. The class-I carcinogen Helicobacter pylori (Hp) activates the non-receptor tyrosine kinase c-Abl to phosphorylate the oncoprotein cytotoxin-associated gene A (CagA). The role of c-Abl in CagA-dependent pathways is well established; however, the knowledge of CagA-independent c-Abl processes is scarce. METHODS: c-Abl phosphorylation and localization were analyzed by immunostaining and immunofluorescence. Interaction partners were identified by tandem-affinity purification. Cell elongation and migration were analyzed in transwell-filter experiments. Apoptosis and cell survival were examined by FACS analyses and MTT assays. In mice experiments and human biopsies, the involvement of c-Abl in Hp pathogenesis was investigated. RESULTS: Here, we investigated the activity and subcellular localization of c-Abl in vitro and in vivo and unraveled the contribution of c-Abl in CagA-dependent and -independent pathways to gastric Hp pathogenesis. We report a novel mechanism and identified strong c-Abl threonine 735 phosphorylation (pAblT735) mediated by the type-IV secretion system (T4SS) effector D-glycero-β-D-manno-heptose-1,7-bisphosphate (βHBP) and protein kinase C (PKC) as a new c-Abl kinase. pAblT735 interacted with 14-3-3 proteins, which caused cytoplasmic retention of c-Abl, where it potentiated Hp-mediated cell elongation and migration. Further, the nuclear exclusion of pAblT735 attenuated caspase-8 and caspase-9-dependent apoptosis. Importantly, in human patients suffering from Hp-mediated gastritis c-Abl expression and pAblT735 phosphorylation were drastically enhanced as compared to type C gastritis patients or healthy individuals. Pharmacological inhibition using the selective c-Abl kinase inhibitor Gleevec confirmed that c-Abl plays an important role in Hp pathogenesis in a murine in vivo model. CONCLUSIONS: In this study, we identified a novel regulatory mechanism in Hp-infected gastric epithelial cells by which Hp determines the subcellular localization of activated c-Abl to control Hp-mediated EMT-like processes while decreasing cell death.

Morey P, Pfannkuch L, Pang E, Boccellato F, Sigal M, Imai-Matsushima A, Dyer V, Koch M, Mollenkopf H-J, Schlaermann P, Meyer TF. 2018. Helicobacter pylori Depletes Cholesterol in Gastric Glands to Prevent Interferon Gamma Signaling and Escape the Inflammatory Response. Gastroenterology, 154 (5), pp. 1391-1404.e9. | Show Abstract | Read more

BACKGROUND & AIMS: Despite inducing an inflammatory response, Helicobacter pylori can persist in the gastric mucosa for decades. H pylori expression of cholesterol-α-glucosyltransferase (encoded by cgt) is required for gastric colonization and T-cell activation. We investigated how cgt affects gastric epithelial cells and the host immune response. METHODS: MKN45 gastric epithelial cells, AGS cells, and human primary gastric epithelial cells (obtained from patients undergoing gastrectomy or sleeve resection or gastric antral organoids) were incubated with interferon gamma (IFNG) or interferon beta (IFNB) and exposed to H pylori, including cagPAI and cgt mutant strains. Some cells were incubated with methyl-β-cyclodextrin (to deplete cholesterol from membranes) or myriocin and zaragozic acid to prevent biosynthesis of sphingolipids and cholesterol and analyzed by immunoblot, immunofluorescence, and reverse transcription quantitative polymerase chain reaction analyses. We compared gene expression patterns among primary human gastric cells, uninfected or infected with H pylori P12 wt or P12Δcgt, using microarray analysis. Mice with disruption of the IFNG receptor 1 (Ifngr1-/- mice) and C57BL6 (control) mice were infected with PMSS1 (wild-type) or PMSS1Δcgt H pylori; gastric tissues were collected and analyzed by reverse transcription quantitative polymerase chain reaction or confocal microscopy. RESULTS: In primary gastric cells and cell lines, infection with H pylori, but not cgt mutants, blocked IFNG-induced signaling via JAK and STAT. Cells infected with H pylori were depleted of cholesterol, which reduced IFNG signaling by disrupting lipid rafts, leading to reduced phosphorylation (activation) of JAK and STAT1. H pylori infection of cells also blocked signaling by IFNB, interleukin 6 (IL6), and IL22 and reduced activation of genes regulated by these signaling pathways, including cytokines that regulate T-cell function (MIG and IP10) and anti-microbial peptides such as human β-defensin 3 (hBD3). We found that this mechanism allows H pylori to persist in proximity to infected cells while inducing inflammation only in the neighboring, non-infected epithelium. Stomach tissues from mice infected with PMSS1 had increased levels of IFNG, but did not express higher levels of interferon-response genes. Expression of the IFNG-response gene IRF1 was substantially higher in PMSS1Δcgt-infected mice than PMSS1-infected mice. Ifngr1-/- mice were colonized by PMSS1 to a greater extent than control mice. CONCLUSIONS: H pylori expression of cgt reduces cholesterol levels in infected gastric epithelial cells and thereby blocks IFNG signaling, allowing the bacteria to escape the host inflammatory response. These findings provide insight into the mechanisms by which H pylori might promote gastric carcinogenesis (persisting despite constant inflammation) and ineffectiveness of T-cell-based vaccines against H pylori.

Boccellato F, Woelffling S, Imai-Matsushima A, Sanchez G, Goosmann C, Schmid M, Berger H, Morey P, Denecke C, Ordemann J, Meyer TF. 2018. Polarised epithelial monolayers of the gastric mucosa reveal insights into mucosal homeostasis and defence against infection. Gut, 68 (3), pp. 400-+. | Show Abstract | Read more

OBJECTIVE: Helicobacter pylori causes life-long colonisation of the gastric mucosa, leading to chronic inflammation with increased risk of gastric cancer. Research on the pathogenesis of this infection would strongly benefit from an authentic human in vitro model. DESIGN: Antrum-derived gastric glands from surgery specimens served to establish polarised epithelial monolayers via a transient air-liquid interface culture stage to study cross-talk with H. pylori and the adjacent stroma. RESULTS: The resulting 'mucosoid cultures', so named because they recapitulate key characteristics of the gastric mucosa, represent normal stem cell-driven cultures that can be passaged for months. These highly polarised columnar epithelial layers encompass the various gastric antral cell types and secrete mucus at the apical surface. By default, they differentiate towards a foveolar, MUC5AC-producing phenotype, whereas Wnt signalling stimulates proliferation of MUC6-producing cells and preserves stemness-reminiscent of the gland base. Stromal cells from the lamina propria secrete Wnt inhibitors, antagonising stem-cell niche signalling and inducing differentiation. On infection with H. pylori, a strong inflammatory response is induced preferentially in the undifferentiated basal cell phenotype. Infection of cultures for several weeks produces foci of viable bacteria and a persistent inflammatory condition, while the secreted mucus establishes a barrier that only few bacteria manage to overcome. CONCLUSION: Gastric mucosoid cultures faithfully reproduce the features of normal human gastric epithelium, enabling new approaches for investigating the interaction of H. pylori with the epithelial surface and the cross-talk with the basolateral stromal compartment. Our observations provide striking insights in the regulatory circuits of inflammation and defence.

Roggenbuck D, Borghi MO, Somma V, Büttner T, Schierack P, Hanack K, Grossi C, Bodio C, Macor P, von Landenberg P et al. 2016. Antiphospholipid antibodies detected by line immunoassay differentiate among patients with antiphospholipid syndrome, with infections and asymptomatic carriers. Arthritis Res Ther, 18 (1), pp. 111. | Show Abstract | Read more

BACKGROUND: Antiphospholipid antibodies (aPL) can be detected in asymptomatic carriers and infectious patients. The aim was to investigate whether a novel line immunoassay (LIA) differentiates between antiphospholipid syndrome (APS) and asymptomatic aPL+ carriers or patients with infectious diseases (infectious diseases controls (IDC)). METHODS: Sixty-one patients with APS (56 primary, 22/56 with obstetric events only, and 5 secondary), 146 controls including 24 aPL+ asymptomatic carriers and 73 IDC were tested on a novel hydrophobic solid phase coated with cardiolipin (CL), phosphatic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, beta2-glycoprotein I (β2GPI), prothrombin, and annexin V. Samples were also tested by anti-CL and anti-β2GPI ELISAs and for lupus anticoagulant activity. Human monoclonal antibodies (humoAbs) against human β2GPI or PL alone were tested on the same LIA substrates in the absence or presence of human serum, purified human β2GPI or after CL-micelle absorption. RESULTS: Comparison of LIA with the aPL-classification assays revealed good agreement for IgG/IgM aß2GPI and aCL. Anti-CL and anti-ß2GPI IgG/IgM reactivity assessed by LIA was significantly higher in patients with APS versus healthy controls and IDCs, as detected by ELISA. IgG binding to CL and ß2GPI in the LIA was significantly lower in aPL+ carriers and Venereal Disease Research Laboratory test (VDRL) + samples than in patients with APS. HumoAb against domain 1 recognized β2GPI bound to the LIA-matrix and in anionic phospholipid (PL) complexes. Absorption with CL micelles abolished the reactivity of a PL-specific humoAb but did not affect the binding of anti-β2GPI humoAbs. CONCLUSIONS: The LIA and ELISA have good agreement in detecting aPL in APS, but the LIA differentiates patients with APS from infectious patients and asymptomatic carriers, likely through the exposure of domain 1.

Boccellato F, Meyer TF. 2015. Bacteria Moving into Focus of Human Cancer. Cell Host Microbe, 17 (6), pp. 728-730. | Show Abstract | Read more

Although bacteria have long been associated with human cancer, drawing causal relationships has been difficult. In this issue of Cell Host & Microbe, Scanu et al. (2015) provide evidence for a transforming activity of Salmonella Typhimurium on predisposed host cells, which can subsequently form tumors in a xenograft model.

Rosato P, Anastasiadou E, Garg N, Lenze D, Boccellato F, Vincenti S, Severa M, Coccia EM, Bigi R, Cirone M et al. 2012. Differential regulation of miR-21 and miR-146a by Epstein-Barr virus-encoded EBNA2. Leukemia, 26 (11), pp. 2343-2352. | Show Abstract | Read more

The discovery of microRNA (miR) represents a novel paradigm in RNA-based regulation of gene expression and their dysregulation has become a hallmark of many a tumor. In virally associated cancers, the host-pathogen interaction could involve alteration in miR expression. Epstein-Barr virus (EBV)-encoded EBNA2 is indispensable for the capacity of the virus to transform B cells in vitro. Here, we studied how it affects cellular miRs. Extensive miR profiling of the virus-infected and EBNA2-transfected B lymphoma cells revealed that oncomiR miR-21 is positively regulated by this viral protein. Conversely, Burkitt's lymphoma (BL) cell lines infected with EBNA2 lacking P3HR1 strain did not show any increase in miR-21. EBNA2 increased phosphorylation of AKT and this was directly correlated with increased miR-21. In contrast, miR-146a was downregulated by EBNA2 in B lymphoma cells. Low miR-146a expression correlates with an elevated level of IRAK1 and type I interferon in EBNA2 transfectants. Taken together, the present data suggest that EBNA2 might contribute to EBV-induced B-cell transformation by altering miR expression and in particular by increasing oncomiR-like miR-21 and by affecting the antiviral responses of the innate immune system through downregulation of its key regulator miR-146a.

Anastasiadou E, Boccellato F, Vincenti S, Rosato P, Bozzoni I, Frati L, Faggioni A, Presutti C, Trivedi P. 2010. Epstein-Barr virus encoded LMP1 downregulates TCL1 oncogene through miR-29b. Oncogene, 29 (9), pp. 1316-1328. | Show Abstract | Read more

Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) is noted for its transforming potential. Yet, it also acts as a cytostatic and growth-relenting factor in Burkitt's lymphoma (BL) cells. The underlying molecular mechanisms of the growth inhibitory property of LMP1 have remained largely unknown. In this study, we show that LMP1 negatively regulates a major oncogene, TCL1, in diffuse large B-cell lymphoma (DLBCL) and BL cells. MicroRNA (miR) profiling of LMP1 transfectants showed that among others, miR-29b, is upregulated. LMP1 diminished TCL1 by inducing miR-29b through C-terminus activation region 1 (CTAR1) and CTAR2. miR-29b locked nucleic acid (LNA) antisense oligonucleotide transfection into LMP1-expressing cells reduced miR-29b expression and consequently reconstituted TCL1, suggesting that LMP1 negatively regulates TCL1 through miR-29b upregulation. The miR-29b increase by LMP1 was due to an increase in the cluster pri-miR-29b1-a transcription, derived from human chromosome 7. Using pharmacological inhibitors, we found that p38 mitogen-activated protein kinase-activating function of LMP1 is important for this effect. The ability of LMP1 to negatively regulate TCL1 through miR-29b might underlie its B-cell lymphoma growth antagonistic property. As LMP1 is also important for B-cell transformation, we suggest that the functional dichotomy of this viral protein may depend on a combination of levels of its expression, lineage and differentiation of the target cells and regulation of miRs, which then directs the outcome of the cellular response.

Anastasiadou E, Vaeth S, Cuomo L, Boccellato F, Vincenti S, Cirone M, Presutti C, Junker S, Winberg G, Frati L et al. 2009. Epstein-Barr virus infection leads to partial phenotypic reversion of terminally differentiated malignant B cells. Cancer Lett, 284 (2), pp. 165-174. | Show Abstract | Read more

The B cell lymphomas associated with Epstein-Barr virus (EBV) are not limited to any specific stage of B cell differentiation but covers widely different B cell phenotypes. In vitro infection of the virus negative tumors with a recombinant EBV strain has provided important insights into virus-tumor interaction. Here, we investigated the interaction between EBV and terminally differentiated tumor derived B cells, namely multiple myeloma (MM). The in vitro EBV infected MM expressed restricted viral latency. Acquisition of the virus was accompanied by a partial reprogramming to a mature B cell phenotype. Thus, the plasma cell markers syndecan-1 (CD138), Blimp1 and MUM1 were downregulated, while expression of HLADR, CIITA and TCL1, which are normally not expressed in plasmacytoid cells, was upregulated. The silenced transcription factor gene encoding Pax5 and its target BLNK were activated. Significantly, the free lambda light chains secreted in the medium were reduced in EBV infected MM clones. Collectively, these results suggest that the restricted EBV latency can cause at least partial phenotypic reversion of terminally differentiated B tumor cells. We suggest that the restricted EBV latent gene expression may not only be the consequence but the cause of the mature B cell phenotype, actively participating in the virus persistence.

Boccellato F, Anastasiadou E, Rosato P, Kempkes B, Frati L, Faggioni A, Trivedi P. 2007. EBNA2 interferes with the germinal center phenotype by downregulating BCL6 and TCL1 in non-Hodgkin's lymphoma cells. J Virol, 81 (5), pp. 2274-2282. | Show Abstract | Read more

Epstein-Barr virus (EBV)-negative diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma-derived cell lines infected in vitro with a recombinant EBV expressed type II/III latency. High expression of EBNA2 inversely correlated with expression of germinal center (GC)-associated genes, BCL6 and TCL1. The decreased expression of BCL6 appeared to be dose dependent, with almost complete abrogation in highly EBNA2-expressing clones. The role of EBNA2 in negative regulation of these genes was confirmed by transfection and in a hormone-inducible EBNA2 cell system. LMP1 transfection reduced expression of TCL1, but not of BCL6, in DLBCLs. The GC-associated gene repression was at the transcriptional level and CBF1 independent. A decrease in HLA-DR, surface immunoglobulin M, and class II transactivator expression and an increase in CCL3, a BCL6 repression target, was observed in EBNA2-expressing clones. Since BCL6 is indispensable for GC formation and somatic hypermutations (SHM), we suggest that the previously reported lack of SHM seen in EBNA2-expressing GC cells from infectious mononucleosis tonsils could be due to negative regulation of BCL6 by EBNA2. These findings suggest that EBNA2 interferes with the GC phenotype.

Anastasiadou E, Boccellato F, Cirone M, Kis LL, Klein E, Frati L, Faggioni A, Trivedi P. 2005. Epigenetic mechanisms do not control viral latency III in primary effusion lymphoma cells infected with a recombinant Epstein-Barr virus. Leukemia, 19 (10), pp. 1854-1856. | Read more

Morey P, Pfannkuch L, Pang E, Boccellato F, Sigal M, Imai-Matsushima A, Dyer V, Koch M, Mollenkopf H-J, Schlaermann P, Meyer TF. 2018. Helicobacter pylori Depletes Cholesterol in Gastric Glands to Prevent Interferon Gamma Signaling and Escape the Inflammatory Response. Gastroenterology, 154 (5), pp. 1391-1404.e9. | Show Abstract | Read more

BACKGROUND & AIMS: Despite inducing an inflammatory response, Helicobacter pylori can persist in the gastric mucosa for decades. H pylori expression of cholesterol-α-glucosyltransferase (encoded by cgt) is required for gastric colonization and T-cell activation. We investigated how cgt affects gastric epithelial cells and the host immune response. METHODS: MKN45 gastric epithelial cells, AGS cells, and human primary gastric epithelial cells (obtained from patients undergoing gastrectomy or sleeve resection or gastric antral organoids) were incubated with interferon gamma (IFNG) or interferon beta (IFNB) and exposed to H pylori, including cagPAI and cgt mutant strains. Some cells were incubated with methyl-β-cyclodextrin (to deplete cholesterol from membranes) or myriocin and zaragozic acid to prevent biosynthesis of sphingolipids and cholesterol and analyzed by immunoblot, immunofluorescence, and reverse transcription quantitative polymerase chain reaction analyses. We compared gene expression patterns among primary human gastric cells, uninfected or infected with H pylori P12 wt or P12Δcgt, using microarray analysis. Mice with disruption of the IFNG receptor 1 (Ifngr1-/- mice) and C57BL6 (control) mice were infected with PMSS1 (wild-type) or PMSS1Δcgt H pylori; gastric tissues were collected and analyzed by reverse transcription quantitative polymerase chain reaction or confocal microscopy. RESULTS: In primary gastric cells and cell lines, infection with H pylori, but not cgt mutants, blocked IFNG-induced signaling via JAK and STAT. Cells infected with H pylori were depleted of cholesterol, which reduced IFNG signaling by disrupting lipid rafts, leading to reduced phosphorylation (activation) of JAK and STAT1. H pylori infection of cells also blocked signaling by IFNB, interleukin 6 (IL6), and IL22 and reduced activation of genes regulated by these signaling pathways, including cytokines that regulate T-cell function (MIG and IP10) and anti-microbial peptides such as human β-defensin 3 (hBD3). We found that this mechanism allows H pylori to persist in proximity to infected cells while inducing inflammation only in the neighboring, non-infected epithelium. Stomach tissues from mice infected with PMSS1 had increased levels of IFNG, but did not express higher levels of interferon-response genes. Expression of the IFNG-response gene IRF1 was substantially higher in PMSS1Δcgt-infected mice than PMSS1-infected mice. Ifngr1-/- mice were colonized by PMSS1 to a greater extent than control mice. CONCLUSIONS: H pylori expression of cgt reduces cholesterol levels in infected gastric epithelial cells and thereby blocks IFNG signaling, allowing the bacteria to escape the host inflammatory response. These findings provide insight into the mechanisms by which H pylori might promote gastric carcinogenesis (persisting despite constant inflammation) and ineffectiveness of T-cell-based vaccines against H pylori.

Boccellato F, Woelffling S, Imai-Matsushima A, Sanchez G, Goosmann C, Schmid M, Berger H, Morey P, Denecke C, Ordemann J, Meyer TF. 2018. Polarised epithelial monolayers of the gastric mucosa reveal insights into mucosal homeostasis and defence against infection. Gut, 68 (3), pp. 400-+. | Show Abstract | Read more

OBJECTIVE: Helicobacter pylori causes life-long colonisation of the gastric mucosa, leading to chronic inflammation with increased risk of gastric cancer. Research on the pathogenesis of this infection would strongly benefit from an authentic human in vitro model. DESIGN: Antrum-derived gastric glands from surgery specimens served to establish polarised epithelial monolayers via a transient air-liquid interface culture stage to study cross-talk with H. pylori and the adjacent stroma. RESULTS: The resulting 'mucosoid cultures', so named because they recapitulate key characteristics of the gastric mucosa, represent normal stem cell-driven cultures that can be passaged for months. These highly polarised columnar epithelial layers encompass the various gastric antral cell types and secrete mucus at the apical surface. By default, they differentiate towards a foveolar, MUC5AC-producing phenotype, whereas Wnt signalling stimulates proliferation of MUC6-producing cells and preserves stemness-reminiscent of the gland base. Stromal cells from the lamina propria secrete Wnt inhibitors, antagonising stem-cell niche signalling and inducing differentiation. On infection with H. pylori, a strong inflammatory response is induced preferentially in the undifferentiated basal cell phenotype. Infection of cultures for several weeks produces foci of viable bacteria and a persistent inflammatory condition, while the secreted mucus establishes a barrier that only few bacteria manage to overcome. CONCLUSION: Gastric mucosoid cultures faithfully reproduce the features of normal human gastric epithelium, enabling new approaches for investigating the interaction of H. pylori with the epithelial surface and the cross-talk with the basolateral stromal compartment. Our observations provide striking insights in the regulatory circuits of inflammation and defence.

Boccellato F, Meyer TF. 2015. Bacteria Moving into Focus of Human Cancer. Cell Host Microbe, 17 (6), pp. 728-730. | Show Abstract | Read more

Although bacteria have long been associated with human cancer, drawing causal relationships has been difficult. In this issue of Cell Host & Microbe, Scanu et al. (2015) provide evidence for a transforming activity of Salmonella Typhimurium on predisposed host cells, which can subsequently form tumors in a xenograft model.

Anastasiadou E, Vaeth S, Cuomo L, Boccellato F, Vincenti S, Cirone M, Presutti C, Junker S, Winberg G, Frati L et al. 2009. Epstein-Barr virus infection leads to partial phenotypic reversion of terminally differentiated malignant B cells. Cancer Lett, 284 (2), pp. 165-174. | Show Abstract | Read more

The B cell lymphomas associated with Epstein-Barr virus (EBV) are not limited to any specific stage of B cell differentiation but covers widely different B cell phenotypes. In vitro infection of the virus negative tumors with a recombinant EBV strain has provided important insights into virus-tumor interaction. Here, we investigated the interaction between EBV and terminally differentiated tumor derived B cells, namely multiple myeloma (MM). The in vitro EBV infected MM expressed restricted viral latency. Acquisition of the virus was accompanied by a partial reprogramming to a mature B cell phenotype. Thus, the plasma cell markers syndecan-1 (CD138), Blimp1 and MUM1 were downregulated, while expression of HLADR, CIITA and TCL1, which are normally not expressed in plasmacytoid cells, was upregulated. The silenced transcription factor gene encoding Pax5 and its target BLNK were activated. Significantly, the free lambda light chains secreted in the medium were reduced in EBV infected MM clones. Collectively, these results suggest that the restricted EBV latency can cause at least partial phenotypic reversion of terminally differentiated B tumor cells. We suggest that the restricted EBV latent gene expression may not only be the consequence but the cause of the mature B cell phenotype, actively participating in the virus persistence.

Understanding the impact of bacterial infections in causing pre-cancerous lesions

The WHO has reported that infections are the cause of one out of five cancer cases in the world. Many of these are related to viruses (HPV, EBV, HCV and others) but there are increasing evidence that also bacterial infections can cause cancer [1, 2].  The strongest epidemiological association has been reported for Helicobacter pylori that is considered responsible for 70% of the gastric malignancies and indeed the WHO has classified H.pylori as class I carcinogen.How does the infection cause ...

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