bioRxiv Science⌕ Search

bioRxiv · 10.1101/2021.11.02.467036

The role of the gut microbiota in the effects of early-life stress and dietary fatty acids on later-life central and metabolic outcomes in mice

Abstract

Early-life stress (ELS) leads to increased vulnerability for mental and metabolic disorders. We have previously shown that dietary low {omega}-6/{omega}-3 polyunsaturated fatty acid (PUFA) ratio is able to protect against ELS-induced cognitive impairments. Due to the importance of the gut microbiota as determinants of long-term health, we here study the impact of ELS and dietary PUFAs on the gut microbiota, and how this relates to the previously described cognitive, metabolic and fatty acid profiles. Male mice were exposed to ELS via the limited bedding and nesting paradigm (postnatal day (P)2 - P9) and to an early diet (P2 - P42) with either high (15) or low (1) {omega}-6 linoleic acid to {omega}-3 alpha-linolenic acid ratio. 16S ribosomal RNA was sequenced and analyzed from fecal samples at P21, P42 and P180. ELS increased {beta}-diversity at P42, which persisted into adulthood. The low {omega}-6/{omega}-3 diet prevented the ELS-induced increase in {beta}-diversity, at P42. At the level of taxa abundance, for example, the abundance of the phyla Bacteroidetes increased while Actinobacteria and Verrucomicrobia decreased with age; ELS reduced the relative abundance of the genera RC9 gut group and Rikenella into adulthood and the low {omega}-6/{omega}-3 diet reduced the abundance of the Firmicutes Erysipelotrichia. At P42, species abundance correlated with body fat mass and circulating leptin (e.g. Bacteroidetes and Proteobacteria taxa) and fatty acid profiles (e.g. Firmicutes taxa). This study gives novel insights into the impact of age, ELS and dietary PUFAs on microbiota composition, providing potential targets for non-invasive (nutritional) modulation of the ELS-induced deficits. ImportanceEarly-life stress (ELS) leads to increased vulnerability to develop mental and metabolic disorders, however the biological mechanisms leading to such programming are not fully clear. Increased attention has been given to the importance of the gut microbiota as determinant of long term health and as potential target for non-invasive nutritional strategies to protect against the negative impact of ELS. Here we give novel insights in the complex interaction between ELS, early dietary {omega}-3 availability and the gut microbiota across ages and provides new potential targets for (nutritional) modulation of the long-term effects of the early-life environment via the microbiota.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Reemst, K., Tims, S., Yam, K.-y., Mischke, M., Knol, J., Brul, S., Schipper, L., Korosi, A.. 2021-11-03. The role of the gut microbiota in the effects of early-life stress and dietary fatty acids on later-life central and metabolic outcomes in mice. https://doi.org/10.1101/2021.11.02.467036

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Microbially conjugated bile acids differentially affect the lifecycle and pathogenesis of Clostridioides difficile

Clostridioides difficile is a Gram-positive bacterium that causes C. difficile infection (CDI). In healthy adults, it has been proposed that the gut microbiota provides colonization resistance against C. difficile by competition through nutrient limitation and antagonism through secondary bile acid metabolism, the latter of which is mediated by the deconjugation of host-derived bile acids with bacterial bile salt hydrolases (BSH). Recently, BSHs have also shown an ability to reconjugate non-canonical (i.e., not glycine or taurine) amino acids to sterol cores, resulting in novel microbially conjugated bile acids (MCBAs). MCBAs have been associated with the resolution of recurrent CDI, though the mechanism underlying these effects are not well understood. To address this gap, we synthesized 36 MCBAs with nine amino acids (cysteine, isoleucine, leucine, phenylalanine, proline, serine, tryptophan, tyrosine, and valine) conjugated to the primary and secondary bile acids found in the human gut (CA, DCA, CDCA, and LCA) and tested their impact on various stages of C. difficiles lifecycle including bacterial outgrowth, membrane integrity, sporulation, and toxin activity. We show that BSH-mediated amidation of bile acid sterol cores can either increase or decrease inhibitory effects on C. difficile in an amino acid-dependent manner. For example, serine MCBAs enhanced C. difficiles ability to grow in otherwise inhibitory bile acid concentrations, increased spore production, and elevated toxin activity. Tryptophan MCBAs increased inhibition. By demonstrating these variable effects, our work clarifies the molecular determinants of MCBA activity and highlights specific MCBAs as promising targets for the development of C. difficile microbial-based therapeutics.

microbiology↗

Magnetic organelle gene clusters enable bacterial growth and ATP homeostasis under oxidizing conditions

Biological organisms can produce magnetic nanoparticles made of magnetite to detect the Earth's magnetic field for orientation. The evolutionary mechanisms that led to the acquisition of this capacity remain unknown. The most ancient organisms known to perform magnetic orientation are magnetotactic bacteria. Under tight genetic control, they produce chains of magnetite nanoparticles in dedicated organelles to allow efficient navigation in aquatic environments containing molecular oxygen. Yet, these bacteria have been proposed to emerge before molecular oxygen became abundant on Earth, at a time when this navigation system could not have served its current function. Here, we show that gene clusters responsible of magnetite formation and organization enable resistance against hydrogen peroxide, a toxic oxygen-derived compound that was produced during the early stages of Earth's oxygenation when iron oxidation consumed molecular oxygen. Characterization of the nanoparticle's oxidation state supported the involvement of magnetite in resistance to hydrogen peroxide-induced oxidative stress. These findings are compatible with an early emergence of magnetotactic bacteria, before natural waters became oxygenated. We propose a conceptual framework to explain the origin of magnetic orientation in bacteria, and offer tools to identify the initiation of Earth's oxygenation in a time-resolved manner.

microbiology↗

Identification and characterization of new P. aeruginosa phages using a surface receptor platform

Bacteriophages are of increasing interest for their potential use as alternatives to antibiotics for treating drug-resistant infections. Phage steering, specifically receptor-based steering, involves use of phages that bias the development of resistance in bacteria towards phenotypes such as reduced fitness. Phage therapy typically involves administering cocktails of phages with different targets to reduce the likelihood of resistance emerging. To ensure effective steering and cocktail design, there is a need to identify the receptors used by phages of interest, and to isolate phages that use diverse receptors. Here we describe a SURFAce Receptor (SURFAR) platform consisting of a set of defined Pseudomonas aeruginosa strains and mutants for rapid characterization of phage receptors. This platform can also be used to enrich for and isolate diverse phages from environmental samples, yielding novel phage genomes from wastewater. Using the SURFAR platform, two new phages were isolated and characterized: Dalewood, which targets both flagella and the conserved LPS outer core, and Bowman, a biofilm targeting phage capable of supressing growth of a subset of carbapenem-resistant clinical isolates. This tool helps to standardize the laborious but important task of phage receptor characterization, with the goal of expanding the known repertoire of P. aeruginosa phage receptors and phages.

microbiology↗