Rats, schizophrenia, and the gut microbiome of bacteria and fungi - a pilot study using Next Generation Sequencing (NGS).
Project manager: Dominika Salamon
Implementation period: 2019 – 2021
Project type: Miniatura 3
RESEARCH PROJECT OBJECTIVES
Information on the relationship between the composition of the intestinal microbiome (especially the deficiency of probiotic bacteria) and the development of inflammatory processes that influence the development of schizophrenia (SCZ) appears in the literature more and more often. This is related to the role and functioning of the gut-brain axis and the likely influence of the gut microbiome on brain development.
The objective of this project was a comprehensive evaluation (qualitative and quantitative, using the next-generation sequencing [NGS] method) of the composition of the microbiota and mycobiota of small and large intestines, intestinal tissues and spleen in SCZ rat model and control group of rats.
RESEARCH METHODOLOGY
The research material were samples of feces, duodenal contents, duodenal and colon tissues and spleen from rodents (a neurodevelopmental model of rats [Sprague-Dawley animals], obtained by administration of methylazoxymethanol [MAM] to females on day 17 of pregnancy, causing anatomical, functional and behavioral disorders in the offspring corresponding to those observed in patients with schizophrenia). With the use of appropriate procedures, bacterial DNA was isolated from these samples and, additionally, from stool samples, fungal DNA of microorganisms inhabiting the organisms of the tested rats was isolated. Using the next-generation sequencing technique (on 2 platforms: MiSeq and iSeq by Illumina) and modern bioinformatic analysis software, the profile of microorganisms and their relative percentage in each of the tested samples was defined.
RESULTS OF THE PROJECT
1) Differences at the genus (L6) level in the bacterial profile of the duodenal contents and the duodenal tissue between the schizophrenia group and the control group suggest that there may be an association between specific bacterial species and schizophrenia, and it concerns the small intestine rather than the large intestine. However, this requires further research, using more samples, and suggests that duodenal biopsies are probably to be of greater value than fecal samples. 2) The presence of the fungus S.cerevisiae in 100% of the feces of a sick group of rats seems to confirm their relationship with schizophrenia. 3) The presence of bacterial genetic material in spleen samples may indicate the translocation of microorganisms from the intestine to this organ due to damage and increased permeability of the intestinal wall. 4) For the above analyses, the MiSeq platform seems to be better than the iSeq platform, as it allows of detailed analysis of the microbiota composition differences in the tested samples, especially at the levels of genus (L6) and species (L7).
The above study allowed to indicate which biological material and what NGS and bioinformatics tools would be most useful in the analysis of the microbiome and became the basis for the development of a wider research project, which received funding from the National Science Center (Sonata 17, project no. 2021/43/D/NZ5/00469 ).