Biology subjects

Le Lay, A.

Publications and source records attributed to Le Lay, A..

3 recordsLinked to original sources

bioRxiv2023

Improved Glucose Homeostasis Following Vertical Sleeve Gastrectomy is Associated with Alternate Wiring of the Liver Molecular Clock in a Rat Model of Spontaneously-Occurring Type 2 Diabetes

Bariatric surgery is associated with remission of type 2 diabetes (T2D). We aimed to advance fundamental understanding of mechanisms involved in improved glucose homeostasis following vertical sleeve gastrectomy (VSG). We carried out a series of pathophysiological, behavioural and liver transcriptome analyses in lean rats of the Goto-Kakizaki (GK) model of polygenic T2D following VSG or sham operation. VSG and resulting sustained reduction in glucose intolerance were associated with significant changes in liver histology and lean mass, and nycthemeral feeding patterns and activity. Liver transcriptome profiling identified differentially regulated pathways between VSG and sham GK, including inflammatory and immune processes and fatty acid metabolism. Deeper analysis of the transcriptome dataset showed that expression of almost all main regulators of the molecular clock was significantly and co-ordinately affected by VSG. Comparisons with liver transcriptome data previously generated in GK and normoglycemic rats suggested that VSG results in a profound remodelling of the regulation of the molecular clock. Our findings shed light on relationships between the molecular clock and nycthemeral feeding and activity, which may contribute to long-term therapeutic consequences of VSG in the context of polygenic T2D in the absence of confounding effects of obesity.

physiology↗

bioRxiv2019

Microbiome Determinants and Physiological Effects of the Benzoate-Hippurate Microbial-Host Co-Metabolic Pathway

ObjectiveGut microbial products are involved in type 2 diabetes, obesity and insulin resistance. In particular, hippurate, a hepatic phase 2 conjugation product of microbial benzoate metabolism, has been associated with a healthy phenotype. This study aims to identify metagenomic determinants and test protective effects of hippurate. DesignWe profiled the urine metabolome by 1H Nuclear Magnetic Resonance (NMR) spectroscopy to derive associations with metagenomic sequences in 271 middle-aged Danish individuals to identify dietary patterns in which urine hippurate levels were associated with health benefits. We follow up with benzoate and hippurate infusion in mice to demonstrate causality on clinical phenotypes. ResultsIn-depth analysis identifies that the urine hippurate concentration is associated with microbial gene richness, microbial functional redundancy as well as functional modules for microbial benzoate biosynthetic pathways across several enterotypes. Through dietary stratification, we identify a subset of study participants consuming a diet rich in saturated fat in which urine hippurate, independently of gene richness, accounts for links with metabolic health that we previously associated with gene richness. We then demonstrate causality in vivo through chronic subcutaneous infusions of hippurate or benzoate (20 nmol/day) resulting in improved glycemic control in mice fed a high-fat diet. Hippurate improved insulin secretion through increased {beta}-cell mass and reduced liver inflammation and fibrosis, whereas benzoate treatment resulted in liver inflammation. ConclusionOur translational study shows that the benzoate-hippurate pathway brings a range of metabolic improvements in the context of high-fat diets, highlighting the potential of hippurate as a mediator of metabolic health.

systems biology↗

bioRxiv2018

The Microbial Metabolite 4-Cresol Improves Glucose Homeostasis and Enhances β-Cell Function

Gut microbiota changes are associated with increased risk of Type 2 diabetes (T2D) and obesity. Through serum metabolome profiling in patients with cardiometabolic disease (CMD) we identified significant inverse correlation between the microbial metabolite 4-cresol and T2D. Chronic administration of non toxic dose of 4-cresol in two complementary preclinical models of CMD reduced adiposity, glucose intolerance and liver triglycerides, and enhanced insulin secretion in vivo, which may be explained by markedly increased pancreas weight, augmented islet density and size, and enhanced vascularisation suggesting activated islet neogenesis. Incubation of isolated islets with 4-cresol enhanced insulin secretion, insulin content and cell proliferation. In both CMD models 4-cresol treatment in vivo was associated with altered expression of SIRT1 and the kinase DYRK1A, which may contribute to mediate its biological effects. Our findings identify 4-cresol as an effective regulator of {beta}-cell function and T2D endophenotypes, which opens therapeutic perspectives in syndromes of insulin deficiency.

physiology↗