Biology subjects

Chamaillard, M.

Publications and source records attributed to Chamaillard, M..

3 recordsLinked to original sources

bioRxiv2025

Poor prognosis in IBD-complicated colon cancer through gut dysbiosis-related immune response failure

BackgroundColorectal cancer (CRC) results from the accumulation of mutations and epigenetic changes in gut epithelial cells likely due to gut microbiota dysbiosis. However, limited research has been done to explore the link between host tumour dysbiosis and disease outcome. MethodsThe mechanisms influencing outcomes of 97 colorectal cancer (CRC) patients, including 13 with Lynch syndrome, 20 with inflammatory bowel disease (IBD), and 64 sporadic cases, were analyzed using a multiomics approach. These patients were categorized into two groups: "disease-free/stable disease" and "progression disease" survival outcomes. The analysis included tumor adherent microbiota composition (16S rRNA), somatic gene mutations (WES), gene expression (RNAseq), immune markers (RNAscope), and immune infiltrate cells (immunohistochemistry). ResultsIBD-CRC patients had worse outcomes than those with Lynch or sporadic CRC, regardless of TNM staging or treatment. Symbiotic bacteria like Lactococcus lactis were significantly reduced in IBD-CRC tissues. Patient outcomes were influenced by the abundance of virulent (Escherichia coli) relative to beneficial bacteria (Lactococcus lactis). Although no significant increase in deleterious somatic mutations was found in IBD-CRC. 16sRNA revealed increased virulent- and decreased anti-inflammatory symbiotic-bacteria correlating with the upregulation of oncogenes and downregulation of anti-oncogenes like PHLPP1. The multiplex in situ hybridization of CD8, IFN{gamma} and PHLPP1 an anti-oncogene revealed significant decrease of immune cells with detectable PHLPP1 expression in IBD-CRC tumour tissues as compared to sporadic CRCs. ConclusionThe poor outcomes in IBD-CRC patients are likely due to gut dysbiosis and immune cell alterations, possibly triggered by microbiota-related epigenetic pathways. What You Need to KnowO_ST_ABSBACKGROUND AND CONTEXTC_ST_ABSColorectal cancer (CRC) is associated with gut microbiota dysbiosis. Inflammatory bowel disease-related CRC (IBD-CRC) is classified as an environment-related condition. NEW FINDINGSIn relation with patient outcomes, tumour tissues from three types of CRC (Sporadic-, IBD-, and Lynch syndrome-CRC) were analyzed using a multiomic approach. This included examining tissue adherent virulent bacteria, gene analyses, and quantifying immune cell infiltration in the mucosa. IBD-CRC patients had the worst outcomes, associated with the down regulation of PHLPP1 gene, virulent/symbiotic imbalance, and immune response failure. LIMITATIONSLack of animal experiments using FMT of fresh stool from IBD-CRC patients. CLINICAL AND TRANSLATIONAL RESEARCH RELEVANCEAmong the different types of CRC, IBD-CRC patients showed a greater imbalance between harmful and beneficial bacteria, along with immune response failure. Lay summaryThis study compares the pathological and clinical characteristics of patients with colorectal cancer (CRC) across three distinct etiologies: sporadic CRC, inflammatory bowel disease (IBD)-associated CRC, and Lynch syndrome-associated CRC (LS-CRC). Distinct differences in tumor-adherent microbiota, gene expression and immune response profiles were observed. Notably, IBD-CRC patients demonstrated the poorest prognosis depending on microbe-host gene interaction highlighting potential biomarkers for disease prognosis and treatment strategies.

immunology↗

bioRxiv2023

Spatially-resolved metabolomic identifies colibactin-specific principles of reprogrammed lipid metabolism to promote cancer progression.

Intratumoral bacteria locally contribute to cellular and molecular tumor heterogeneity that support cancer stemness through poorly understood mechanisms. This study aims to explore how Colibactin-producing Escherichia coli (CoPEC) flexibly alters the tumor microenvironment in right-sided colorectal cancer (CRC). Metabolomic and transcriptomic spatial profiling uncovered that CoPEC colonization establishes a high-glycerophospholipid microenvironment within the tumor that is conducive to exhaustion of infiltrated CD8+ T cell and has a lowered prognostic value in right-sided CRC. Mechanistically, the accumulation of lipid droplets in infected cancer cells relied on the production of colibactin as a measure to limit genotoxic stress and supply with sufficient energy for sustaining cell survival and lowering tumor immunogenicity. Specifically, a heightened phosphatidylcholine remodeling of CoPEC-infected cancer cells by the enzyme of the Lands cycle coincided with a lowered accumulation of proapoptotic ceramide and lysophosphatidylcholine. Consequently, a reduced infiltration of CD8+ T lymphocytes that produce the cytotoxic cytokines IFN-{gamma} was found where invading bacteria have been geolocated. By contrast, such an immunosuppressive dysmetabolic process was not observed when human colon cancer cells were infected with the mutant strain that did not produce colibactin (11G5{delta}ClbQ). This work revealed an unexpected property of CoPEC on lipid overload within tumors that could locally provide an inflammatory environment leading to immunosuppressive mechanisms and tumor expansion. This may pave the way for improving chemoresistance and subsequently outcome of CRC patients who are colonized by CoPEC.

cancer biology↗

bioRxiv2022

Monocyte intrinsic NOD2 signalling inhibits pathogenic macrophage differentiation and its loss in inflammatory macrophages improves intestinal inflammation.

ObjectiveIt is believed that intestinal recruitment of monocytes from Crohns Disease (CD) patients who carry NOD2 risk alleles may repeatedly give rise to recruitment of pathogenic macrophages. We investigated an alternative possibility that NOD2 may rather inhibit their differentiation from intravasating monocytes. DesignThe monocyte fate decision was examined by using germ-free mice, mixed bone marrow chimeras and a culture system yielding macrophages and monocyte-derived dendritic cells (mo-DCs). We next asked whether Nod2 in either monocytes or tissue macrophages have distinct resolving properties in colitis. ResultsDespite a similar abundance of monocytes, the intestinal frequency of mo-DCs from Nod2-deficient mice was lowered independently of the changes in the gut microbiota that are caused by Nod2 deficiency. Similarly, the pool of mo-DCs was poorly reconstituted with mobilized bone marrow Nod2-deficient cells. The use of pharmacological inhibitors revealed that activated NOD2 at an early stage of development dominantly inhibits mTOR-mediated macrophage differentiation in a TNFalpha-dependent manner. These observations were supported by the identification of a TNFalpha-dependent response to MDP that is specifically lost in CD14-expressing blood cells bearing the frameshift mutation in NOD2. Accordingly, loss of NOD2 in monocytes lowers glycolytic reserve, CD115 expression and pro-resolving features. Dietary intake of aryl hydrocarbon receptor (AHR) agonists that promotes mo-DCs generation improves colitis in Nod2-deficient mice to the same extent as what is observed upon macrophage ablation of Nod2. ConclusionNOD2 negatively regulates a macrophage developmental program through a feed-forward loop that could be exploited for overcoming resistance to anti-TNF therapy in CD. Significance of this studyO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LILoss of NOD2 function is predisposing to Crohns disease. C_LIO_LIRapamycin, a serine/THR kinase inhibitor of mammalian target (mTOR) has been reported as potentially effective treatment in discrete subset of CD patients with refractory colitis. C_LIO_LIThe NOD2 protein promotes the chemokine CCL2-dependent recruitment of inflammatory monocytes in response to tissue injury. C_LIO_LIAn accumulation of CCR2-expressing monocytes and inflammatory macrophages is observed within the intestinal mucosa of CD patients including those resistant to anti-TNF therapy. C_LIO_LIActivated NOD2 enhances proinflammatory activity of CX3CR1intLy6Chi effector monocytes. C_LIO_LIThe monocyte fate toward mo-DCs is orchestrated by the aryl hydrocarbon receptor. C_LI What are the new findings?O_LINOD2 has a hierarchically dominant negative role on the mTORC-driven monocyte conversion to inflammatory macrophages independently of the changes in the gut microbiota that are caused by Nod2 deficiency. C_LIO_LIA defect in monocytes fate at the early stage allow the expansion of pathogenic macrophages in Nod2-deficient mice at the expense of mo-DC. C_LIO_LIAdoptive transfer of Nod2-deficient monocytes into wild-type mice was sufficient to exacerbate DSS-induced intestinal damage. C_LIO_LIThe glycolytic reserve of monocytes and their ability to respond to M-CSF is lowered upon loss of NOD2 signalling. C_LIO_LIDeletion of NOD2 in macrophage improves colitis to the same extent as dietary supplementation of AHR agonist in mice. C_LIO_LIThe recognition of the gut microbiota by NOD2 is required for de novo reconstitution of mo-DCs in the lamina propria of the murine intestine, while having minimal effect on the mobilization of their precursors to the intestinal mucosa. C_LI How might it impact on clinical practice in the foreseeable future?This study might contribute to the development of novel mTORC-based therapeutic strategies for improving the response to biologics by restoring the ability of circulating monocytes to reconstitute the pool of mo-DCs during homeostatic turnover and upon tissue injury. It may thereby prevent the accumulation of pathogenic macrophages in patients with loss-of-function NOD2 alleles, which fail to respond to anti-TNF and are at greater risk of developing stricturing disease.

immunology↗