Project description:Abstract: Our intake of ultra-processed foods has dramatically increased over the past few decades in line with the prevalence of obesity and diabetes, key risk factors for microvascular diseases such as chronic kidney disease (CKD). The extent to which long-term intake of highly processed food influences CKD outcome is unclear. Here, we show in rodent models that a highly processed diet drives intestinal barrier permeability and an increased risk of CKD. Inhibition of the advanced glycation pathway, which generates Maillard reaction products within foods upon thermal processing, reversed kidney injury. Consequently, a highly processed diet leads to innate immune complement activation and local kidney inflammation via the potent proinflammatory effector molecule complement 5a (C5a). C5a receptor inhibition ameliorated albuminuria. In a mouse model of diabetes, a high resistant starch fiber diet led to a redistribution of the gut commensal consortium, prevented impaired gut barrier function and decreased the severity of kidney injury via suppression of complement. These results provide mechanistic insight into the role of highly processed foods on inflammation and chronic disease risk. One Sentence Summary: Ultra-processed diets promote chronic kidney disease
Project description:To study the role of RNF213, we generated RNF213-deficient human cerebral microvascular endothelial cells by the CRISPR-Cas9 double nickase method and showed that RNF213 may be an important regulator of the blood-brain barrier permeability and homeostasis
Project description:Modern lifestyle is associated with a major consumption of ultra-processed foods (UPF) due to their practicality and palatability. The ingestion of emulsifiers, a main additive in UPFs, has been related to gut inflammation, microbiota dysbiosis, adiposity and obesity. Maternal unbalanced nutritional habits during embryonic and perinatal stages perturb offspring’s long-term metabolic health, thus increasing obesity and associated comorbidity risk. However, whether maternal emulsifier consumption influences developmental programming in the offspring remains unknown. Here we show that, in mice, maternal consumption of dietary emulsifiers (1% CMC and 1% P80 in drinking water), during gestation and lactation, perturbs the development of hypothalamic energy balance regulation centers of the progeny, leads to metabolic impairments, cognition deficits and induces anxiety-like traits in a sex-specific manner. Our findings support the notion that maternal consumption of emulsifiers, common additives of UPFs, causes mild metabolic and neuropsychological malprogramming in the progeny. Our data call for nutritional advice during gestation.
Project description:Background and Objectives: Antibiotic (ABx) therapy is associated with an increased risk for Crohn´s Disease but the underlying mechanisms are unknown. We observed high fecal serine protease activity (PA) to be a frequent side effect of ABx therapy in patients. The aim of the present study was to unravel whether this rise in PA may promote colitis development via detrimental effects on the large intestinal barrier. Design: Transwell experiments were used to assess the impact of high PA in ABx-treated patients or vancomycin/metronidazole (V/M)-treated mice on the epithelial barrier. Serine protease profiling was performed using LC-MS/MS analysis. The impact of high PA on the intestinal barrier in WT/IL10-/- mice and on colitis development in IL10-/- mice was investigated using V/M+/-oral serine protease inhibitor (AEBSF) treatment. Results: The ABx-induced high PA was found to be due to significantly increased levels of pancreatic proteases and to impair the epithelial barrier. In WT mice, the rise in PA caused a transient increase in intestinal permeability but did not affect susceptibility towards DSS-induced acute colitis. In IL10-/- mice, the rise in PA caused a lasting impairment of the intestinal barrier, which was associated with inflammatory activation of the large intestinal tissue. In the long term, the lasting increase in PA upon repeated V/M treatment aggravated colitis development in IL10-/-mice. Conclusion: High PA is a frequent adverse effect of ABx therapy which is detrimental to the large intestinal barrier and may contribute to the development of chronic inflammation in genetically susceptible individuals.
Project description:The precise regulation of blood-brain-barrier (BBB) permeability for immune cells and blood-borne substances is essential to maintain brain homeostasis. Sphingosine-1-phosphate (S1P), a lipid signaling molecule enriched in plasma, is known to affect BBB permeability. Previous studies focussed on endothelial S1P receptors 1 and 2, reporting a barrier-protective effect of S1P1 and a barrier-disruptive effect of S1P2. Here we present novel data characterizing the expression, localization and function of the hitherto exclusively immunce cell-associated S1P receptor 4 (S1P4) on primary brain microvascular endothelial cells (BMECs). We detected a robust expression of S1P4 in homeostatic BMECs and pinpointed its localization to abluminal endothelial membranes by electron microscopy. Basolateral S1P treatment of BMECs led to increased permeability in vitro associated with S1P4 downregulation. Likewise, downregulation of S1P4 was observed in mouse brain microvessels after stroke, a neurological disease associated with BBB impairment. RNA sequencing analysis of BMECs suggested involvement of S1P4 in endothelial homeostasis, apicobasal polarity and barrier function. Using siRNA, pharmacological agonists and antagonists of S1P4 both in vitro and in vivo, we demonstrate a barrier-protective function of S1P4. We therefore suggest S1P4 as a novel target regulating BBB permeability and propose its therapeutic targeting in CNS diseases associated with BBB dysfunction.
Project description:The effect of neuronal activity on blood-brain barrier function and whether it plays a role in plasticity in the healthy brain remains unclear. We show that neuronal activity induces modulation of microvascular permeability in the healthy brain and that it has a role in local network reorganization. Combining simultaneous electrophysiological recording and vascular imaging with transcriptomic analysis in rats, and functional and BBB-mapping MRI in human subjects we show that prolonged stimulation of the limb induces a focal increase in BBB permeability in the corresponding somatosensory cortex that is associated with long-term synaptic plasticity. We further show that the increased microvascular permeability depends on neuronal activity and involves caveolae-mediated transcytosis and transforming growth factor beta signaling. Our results reveal a role of BBB modulation in cortical plasticity in the healthy brain, highlighting the importance of neurovascular interactions for sensory experience and learning.
Project description:The ERC “MINERVA” project (GA 724734) aims at developing a multi-organ-on-a-chip engineered platform to recapitulate in vitro the main players involved in the MGBA crosstalk: the microbiota, the gut epithelium, the immune system, the blood-brain barrier and the brain. In this context, the gut epithelium represents a physiological barrier that separates the intestinal lumen from the systemic circulation, and in several pathological circumstances, seems that its permeability might significantly increase and allow the passage of biologically active molecules into the blood vessels surrounding the intestinal mucosa. In the present work, we present our MINERVA 2.0 device and our innovative gut-on-a-chip device obtained by culturing in MINERVA 2.0 and a human gut epithelial CaCo2 cell based model. In particular, we have cultured the cells under perfusion and have assessed cell behavior by addressing cellular viability, tight junction imaging, apparent permeability by FITC-Dextran and transepithelial electrical resistance evaluation. Transcriptomic profile was used to further elucidate the effects of dynamic perfusion on Caco-2 cells.
Project description:Blood-brain barrier (BBB) dysfunction is emerging as a key pathogenic factor in the progression of Alzheimer’s disease (AD), where increased microvascular endothelial permeability has been proposed to play an important role. However, the molecular mechanisms leading to increased brain microvascular permeability in AD are not fully understood. We observed that brain endothelial permeability in the APPswe/PS1DE9 (APP/PS1) transgenic mouse model of amyloid-beta (Ab) amyloidosis increases with aging in the areas with the greatest amyloid plaque deposition. We performed an unbiased bulk RNA-sequencing analysis of brain endothelial cells (BECs) in APP/PS1 transgenic mice. We observed that upregulation of interferon signaling gene expression pathways in BECs were among the most prominent transcriptomic signatures in the brain endothelium of APP/PS1 mice. Immunofluorescence analysis of isolated BECs from APP/PS1 mice demonstrated higher levels of the Type I interferon-stimulated gene IFIT2. Immunoblotting of APP/PS1 BECs showed downregulation of the adherens junction protein VE-cadherin. Stimulation of human brain endothelial cells with interferon-β decreased the levels of the adherens junction protein VE-cadherin as well as tight junction proteins Occludin and Claudin-5 and increased barrier leakiness. Depletion of the Type I interferon receptor in human brain endothelial cells prevented interferon-β-induced VE- cadherin downregulation and restored endothelial barrier integrity. Our study suggests that Type I interferon signaling contributes to brain endothelial dysfunction in AD.
Project description:Increased intestinal permeability is associated to the onset of inflammatory bowel disease (IBD) since the exposition to luminal content causes an immunological response that promotes intestinal inflammation. Several studies have been shown that microRNAs (miRNAs) are involved in IBD pathogenesis. Here, we aimed to functionally characterize the role of miRNAs in the regulation of intestinal permeability. miRNA profile of intestinal epithelial cells (IECs) isolated by colon of a UC mice model were identified using microarray. To predict the target genes of modulated miRNAs, we performed a bioinformatic analysis. To validate biologically miRNA targets, we performed transient transfection experiments in HT-29, Caco2 and T84 cell lines. To assess their role in barrier function, trans-epithelial electrical resistance and dextran flux assays were used. To investigate the in vivo effect of miR-195-5p, we employed a DSS-induced colitis model in mice. We identified 18 deregulated miRNAs in IECs from UC mice model and control mice. Among them, down-regulated miR-195-5p targeted CLDN2 and are involved in altered intestinal permeability. CLDN2 expression levels were increased in UC mice models and negatively correlated with the miR-195-5p expression. We demonstrated that the gain-of-function of miR-195-5p in colonic epithelial cell lines decreased the CLDN2 levels. We in vitro confirmed that miR-195-5p was able to control the intestinal barrier integrity. We also in vivo demonstrated that miR-195-5p attenuated the colonic inflammatory response in DSS-induced colitis and reduced the colonic permeability. All together our data support a previously unreported role of miR-195-5p in intestinal permeability and provide a potential pharmacological target for new therapeutic approaches in IBD.