Publications by authors named "Velin D"

The microbiome is now regarded as one of the hallmarks of cancer and several strategies to modify the gut microbiota to improve immune checkpoint inhibitor (ICI) activity are being evaluated in clinical trials. Preliminary data regarding the upper gastro-intestinal microbiota indicated that seropositivity was associated with a negative prognosis in patients amenable to ICI. In 97 patients with advanced melanoma treated with ICI, we assessed the impact of on outcomes and microbiome composition.

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infects the gastric mucosa of a large number of humans. Although asymptomatic in the vast majority of cases, infection can lead to the development of peptic ulcers gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Using a variety of mechanisms, locally suppresses the function of the host immune system to establish chronic infection.

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Background: Helicobacter pylori (H. pylori) colonizes the human gastric mucosa with a high worldwide prevalence. Currently, H.

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Unlabelled: Several approaches to manipulate the gut microbiome for improving the activity of cancer immune-checkpoint inhibitors (ICI) are currently under evaluation. Here, we show that oral supplementation with the polyphenol-rich berry camu-camu (CC; Myrciaria dubia) in mice shifted gut microbial composition, which translated into antitumor activity and a stronger anti-PD-1 response. We identified castalagin, an ellagitannin, as the active compound in CC.

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The mechanisms maintaining adult lymphatic vascular specialization throughout life and their role in coordinating inter-organ communication to sustain homeostasis remain elusive. We report that inactivation of the mechanosensitive transcription factor in adult lymphatic endothelium leads to a stepwise intestine-to-lung systemic failure. loss compromised the gut epithelial barrier, promoted dysbiosis and bacterial translocation to peripheral lymph nodes, and increased circulating levels of purine metabolites and angiopoietin-2.

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Objective: In this study, we determined whether () infection dampens the efficacy of cancer immunotherapies.

Design: Using mouse models, we evaluated whether immune checkpoint inhibitors or vaccine-based immunotherapies are effective in reducing tumour volumes of -infected mice. In humans, we evaluated the correlation between seropositivity and the efficacy of the programmed cell death protein 1 (PD-1) blockade therapy in patients with non-small-cell lung cancer (NSCLC).

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Helicobacter pylori (Hp) colonizes the human gastric mucosa with a high worldwide prevalence. Currently, Hp can be eradicated by the use of antibiotics. Due to the increase of antibiotic resistance, new therapeutic strategies need to be devised: one such approach being prophylactic vaccination.

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Expression of Toll-interacting protein (Tollip), a potent TLR modulator, decreases in patients with inflammatory bowel diseases (IBD), whereas Tollip mice are susceptible to colitis. Tollip expression was shown to be reduced in sporadic adenoma. In contrast, we found variable Tollip expression in patients with colitis-associated adenomas.

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The maintenance of homeostasis in the gut is a major challenge for the immune system. Here we demonstrate that the transcription factor MAF plays a central role in T cells for the prevention of gastro-intestinal inflammation. Conditional knock out mice lacking Maf in all T cells developed spontaneous late-onset colitis, correlating with a decrease of FOXP3RORγt T cells proportion, dampened IL-10 production in the colon and an increase of inflammatory T17 cells.

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Ulcerative colitis (UC) has a prevalence of 1 in 1000 inhabitants in Switzerland. The diagnosis of UC is based on a typical clinical presentation that involves bloody diarrhea, characteristic endoscopic features with continuous inflammation involving the rectum, and compatible histology. UC develops in genetically susceptible individuals with a dysregulated mucosal immune system.

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Background: Tollip is a ubiquitously expressed protein, originally described as a modulator of the IL-1R/TLR-NF-κB signaling pathways. Although this property has been well characterized in peripheral cells, and despite some evidence of its expression in the central nervous system, the role of Tollip in neuroinflammation remains poorly understood. The present study sought to explore the implication of Tollip in inflammation in the substantia nigra pars compacta, the structure affected in Parkinson's disease.

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The tight control of the innate and adaptive immune responses in the stomach mucosa during chronic Helicobacter pylori infection is of prime importance for the bacteria to persist and for the host to prevent inflammation-driven diseases. This review summarizes recent data on the roles of innate and adaptive immune responses during H. pylori/host interactions.

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One of the major toxins secreted by H. pylori is the Vacuolating cytotoxin A (VacA) named after its ability to induce the formation of "vacuole"-like membrane vesicles in the cytoplasm of gastric cells. VacA has been associated with the disruption of mitochondrial functions, stimulation of apoptosis, blockade of T cell proliferation and promotion of regulatory T cells, thereby making it a promising vaccine target.

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Innate immune responses are key to maintain adequate host-microbial interactions. However, those signals are needed to efficiently trigger rapid and targeted antimicrobial responses in case of pathogen encounter. Several molecules have evolved to regulate intensity and coordinate signaling to avoid detrimental consequences to the host.

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Despite the recent description of the mucosal vaccine-induced reduction of Helicobacter pylori natural infection in a phase 3 clinical trial, the absence of immune correlates of protection slows the final development of the vaccine. In this study, we evaluated the role of interleukin (IL)-22 in mucosal vaccine-induced protection. Gastric IL-22 levels were increased in mice intranasally immunized with urease+cholera toxin and challenged with H.

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Despite the proven ability of immunization to reduce Helicobacter infection in mouse models, the precise mechanism of protection has remained elusive. In this study, we evaluated the role of inflammatory monocytes in the vaccine-induced reduction of Helicobacter felis infection. We first showed by using flow cytometric analysis that Ly6C(low) major histocompatibility complex class II-positive chemokine receptor type 2 (CCR2)-positive CD64(+) inflammatory monocytes accumulate in the stomach mucosa during the vaccine-induced reduction of H.

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NLR family apoptosis inhibitory proteins (NAIPs) belong to both the Nod-like receptor (NLR) and the inhibitor of apoptosis (IAP) families. NAIPs are known to form an inflammasome with NLRC4, but other in vivo functions remain unexplored. Using mice deficient for all NAIP paralogs (Naip1-6(Δ/Δ)), we show that NAIPs are key regulators of colorectal tumorigenesis.

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Objective: Macrophages play a critical role in intestinal wound repair. However, the molecular pathways that regulate macrophage wound repair activities remain poorly understood. The aim of this study was to evaluate the role of GM-CSF receptor signaling in the wound repair activities of macrophages.

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Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H.

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Background: The intestinal epithelium accommodates with a myriad of commensals to maintain immunological homeostasis, but the underlying mechanisms regulating epithelial responsiveness to flora-derived signals remain poorly understood. Herein, we sought to determine the role of the Toll/interleukin (IL)-1 receptor regulator Toll-interacting protein (Tollip) in intestinal homeostasis.

Methods: Colitis susceptibility was determined after oral dextran sulfate sodium (DSS) administration or by breeding Tollip on an IL-10 background.

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Objective: Macrophages play a critical role in wound repair. However, the specific role of the different macrophage subtypes in wound repair remains incompletely understood. The aim of this study was to compare the wound repair activities of undifferentiated macrophages (M0), classically activated macrophages (M1) and alternatively activated (M2) macrophages.

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Celiac disease is a well-known entity in pediatrics and pediatric gastroenterology that is now also frequently encountered in the adult population. Apart from typical symptoms, celiac disease can present with a wide range of manifestations that are sometimes atypical, scarce or purely extraintestinal. Serologic and genetic testing are useful tools in case of low clinical probability in the early diagnostic algorithm.

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Macrophages play a critical role in intestinal wound repair. However, the mechanisms of macrophage-assisted wound repair remain poorly understood. We aimed to characterize more clearly the repair activities of murine and human macrophages.

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Inflammatory bowel diseases are commonly complicated by weight and bone loss. We hypothesized that IL-15, a pro-inflammatory cytokine expressed in colitis and an osteoclastogenic factor, could play a central role in systemic and skeletal complications of inflammatory bowel diseases. We evaluated the effects of an IL-15 antagonist, CRB-15, in mice with chronic colitis induced by oral 2% dextran sulfate sodium for 1 week, followed by another 1% for 2 weeks.

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The second scientific workshop of the European Crohn's and Colitis Organization (ECCO) focused on the relevance of intestinal healing for the disease course of inflammatory bowel disease (IBD). The objective was to better understand basic mechanisms, markers for disease prediction, detection and monitoring of intestinal healing, impact of intestinal healing on the disease course of IBD as well as therapeutic strategies. The results of this workshop are presented in four separate manuscripts.

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