The role of selenium in shaping mice brain metabolome and selenoproteome through the gut-brain axis by combining metabolomics, metallomics, gene expression, and amplicon sequencing

Selenium (Se) is a trace element crucial for human health. Recently, the impact of Se supplementation on gut microbiota has been pointed out as well as its influence on the expression of certain selenoproteins and gut metabolites. This study aims to elucidate the link between Se supplementation, brain selenoproteins and brain metabolome as well as the possible connection with the gut-brain axis. To this end, an in vivo study with 40 BALB/c mice was carried out. The study included conventional (n=20) and mice model with microbiota depleted by antibiotics (n=20) under a regular or Se supplemented diet. Brain selenoproteome was determined by a transcriptomic/gene expression profile, while brain metabolome and gut microbiota profiles were accomplished by untargeted metabolomics and amplicon sequencing, respectively. The total content of Se in brain was also determined. The selenoproteins genes Dio and Gpx isoenzymes, SelenoH, SelenoI, SelenoT, SelenoV, and SelenoW and 31 metabolites were significantly altered in the brain after Se supplementation in conventional mice, while 11 selenoproteins and 26 metabolites were altered in microbiota depleted mice. The main altered brain metabolites were related to glyoxylate and dicarboxylate metabolism, amino acid metabolism, and gut microbiota that have been previously related with the gut-brain axis (e.g., members of Lachnospiraceae and Ruminococcaceae families). Moreover, specific associations were determined between brain selenoproteome and metabolome, which correlated with the same bacteria, suggesting an intertwined mechanism. Our results demonstrated the effect of Se on brain metabolome through specific selenoproteins gene expression and gut microbiota.
This work was supported by the projects: PG2018-096608-B-C21 and PID2021-123073NB-C21 from the Spanish Ministry of Science and Innovation (MICIN). Generación del Conocimiento. MCIN/ AEI /10.13039/501100011033/ FEDER “Una manera de hacer Europa”, UHU-1256905 and UHU-202009 from the FEDER Andalusian Operative Program 2014-2020 (Ministry of Economy, Knowledge, Business and Universities, Regional Government of Andalusia, Spain). S.R.A. thanks the Spanish Ministry of Science and Innovation for a PhD scholarship (BES-2016-076364). The authors are grateful to FEDER (European Community) for financial support, Grant UNHU13-1E-1611. The authors would like to acknowledge the support from The Ramón Areces Foundation (ref. CIVP19A5918). Funding for open access charge: Universidad de Huelva / CBUA.