RESUMO
Tryptophan (Trp) is an essential amino acid, whose metabolism is a key gatekeeper of intestinal homeostasis. Yet, its systemic effects, particularly on atherosclerosis, remain unknown. Here we show that high-fat diet (HFD) increases the activity of intestinal indoleamine 2, 3-dioxygenase 1 (IDO), which shifts Trp metabolism from the production of microbiota-derived indole metabolites towards kynurenine production. Under HFD, the specific deletion of IDO in intestinal epithelial cells leads to intestinal inflammation, impaired intestinal barrier, augmented lesional T lymphocytes and atherosclerosis. This is associated with an increase in serotonin production and a decrease in indole metabolites, thus hijacking Trp for the serotonin pathway. Inhibition of intestinal serotonin production or supplementation with indole derivatives alleviates plaque inflammation and atherosclerosis. In summary, we uncover a pivotal role of intestinal IDO in the fine-tuning of Trp metabolism with systemic effects on atherosclerosis, paving the way for new therapeutic strategies to relieve gut-associated inflammatory diseases.
Assuntos
Aterosclerose , Dieta Hiperlipídica , Indolamina-Pirrol 2,3,-Dioxigenase , Mucosa Intestinal , Camundongos Endogâmicos C57BL , Serotonina , Triptofano , Animais , Triptofano/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenase/genética , Aterosclerose/metabolismo , Aterosclerose/patologia , Aterosclerose/genética , Aterosclerose/tratamento farmacológico , Dieta Hiperlipídica/efeitos adversos , Camundongos , Serotonina/metabolismo , Mucosa Intestinal/metabolismo , Cinurenina/metabolismo , Masculino , Microbioma Gastrointestinal , Indóis/farmacologia , Inflamação/metabolismo , Camundongos Knockout , Intestinos/patologia , Linfócitos T/metabolismo , Linfócitos T/imunologia , Modelos Animais de DoençasRESUMO
Although high-fat diet (HFD)-induced gut microbiota dysbiosis is known to affect atherosclerosis, the underlying mechanisms remain to be fully explored. Here, we show that the progression of atherosclerosis depends on a gut microbiota shaped by an HFD but not a high-cholesterol (HC) diet and, more particularly, on low fiber (LF) intake. Mechanistically, gut lymphoid cells impacted by HFD- or LF-induced microbiota dysbiosis highly proliferate in mesenteric lymph nodes (MLNs) and migrate from MLNs to the periphery, which fuels T cell accumulation within atherosclerotic plaques. This is associated with the induction of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) within plaques and the presence of enterotropic lymphocytes expressing ß7 integrin. MLN resection or lymphocyte deficiency abrogates the pro-atherogenic effects of a microbiota shaped by LF. Our study shows a pathological link between a diet-shaped microbiota, gut immune cells, and atherosclerosis, suggesting that a diet-modulated microbiome might be a suitable therapeutic target to prevent atherosclerosis.
Assuntos
Aterosclerose , Microbiota , Placa Aterosclerótica , Humanos , Animais , Camundongos , Disbiose/induzido quimicamente , Linfócitos , Dieta Hiperlipídica/efeitos adversos , Camundongos Endogâmicos C57BLRESUMO
In vitro modeling of the different steps of immune cell recruitment is essential to decipher the role of endothelial cells in this process. Here, we present a protocol for the assessment of human monocyte transendothelial migration using a live cell imaging system. We describe steps for culture of fluorescent monocytic THP-1 cells and chemotaxis plate preparation with HUVEC monolayers. We then detail real-time analysis using the IncuCyte® S3 live-cell imaging system, image analysis, and assessment of transendothelial migration rates. For complete details on the use and execution of this protocol, please refer to Ladaigue et al.1.
Assuntos
Monócitos , Migração Transendotelial e Transepitelial , Humanos , Movimento Celular , Células Endoteliais , QuimiotaxiaRESUMO
Radiation therapy damages tumors and normal tissues, probably in part through the recruitment of immune cells. Endothelial high-mannose N-glycans are, in particular, involved in monocyte-endothelium interactions. Trimmed by the class I α-mannosidases, these structures are quite rare in normal conditions. Here, we show that the expression of the endothelial α-mannosidase MAN1C1 protein decreases after irradiation. We modeled two crucial steps in monocyte recruitment by developing in vitro real-time imaging models. Inhibition of MAN1C1 expression by siRNA gene silencing increases the abundance of high-mannose N-glycans, improves the adhesion of monocytes on endothelial cells in flow conditions and, in contrast, decreases radiation-induced transendothelial migration of monocytes. Consistently, overexpression of MAN1C1 in endothelial cells using lentiviral vectors decreases the abundance of high-mannose N-glycans and monocyte adhesion and enhances transendothelial migration of monocytes. Hence, we propose a role for endothelial MAN1C1 in the recruitment of monocytes, particularly in the adhesion step to the endothelium.