Bioinformaticians have figured out which proteins in human blood are associated with genetics and which with bacteria in the intestine
An international team of researchers, which included Darya Zhernakova a bioinformatician St Petersburg University, has found out how the human genome and microbiome affect the 91 levels of serum protein.
This research will help in the future to find links between changes in the composition of intestinal bacteria and various diseases that people face. The results of the work are published in the journal Nature Genetics.
Recent studies in the field of intestinal microbiome (a community of bacteria that live in symbiosis with a person) suggest that many diseases are accompanied by noticeable changes in the composition of bacteria. These are diseases of the gastrointestinal tract, obesity, cardiovascular diseases and, surprisingly, for example, rheumatoid arthritis, multiple sclerosis and even autism. In some cases, doctors manage to treat these ailments by adding certain types of bacteria to the human intestines. However, the mechanism of many diseases still remain a mystery for scientists. What problems are caused only by genetics? Which ones are caused exclusively by intestinal bacteria? And when should one take into account both the genome and the microbiome?
To get closer to the solution, bioinformaticians from the University of Groningen (Netherlands), University of Bonn (Germany), University of Oslo (Norway) with the participation of Darya Zhernakova, Research Worker of Feodosy Dobrzhansky St Petersburg University Centre of Genomic Bioinformatics analysed the data of almost one and a half thousand people from the LifeLines DEEP project. It contains information about healthy Dutchmen, including data on serum proteins, microbiome, metabolites, gene expression, as well as information about lifestyle, diet, medication and much more.
The researchers found that the levels of 41 proteins from the list are associated with microbial factors, 73 types of proteins are affected by human genetics, there is also 31 proteins whose level depends on both the genome and the microbiome. Moreover, as Darya Zhernakova noted, proteins associated with bacteria are mainly substances involved in the metabolism. This is logical because the microbiome plays an important role in this process, and proteins associated with genetics are substances that are important in the immune system and in various inflammatory processes.
«For one of the proteins, we were able to determine a causal relationship. This is Ep-CAM epithelial protein. It is a biomarker, and plays an important role in the diagnosis of cancer among other things. According to our data, inter-individual differences in the level of this protein depend on genetics for 7%, and microbiomes for 26%. It turned out that, most likely, the FUT2 gene first affects the Ep-CAM protein, and the Ep-CAM protein in its turn affects intestinal bacteria of the genus Blautia,» said Darya Zhernakova
As the researcher notes, this information is useful for doctors, because changes in the FUT2 gene are associated with a group of inflammatory bowel diseases, which include, for example, Crohn’s disease and ulcerative colitis. Knowledge of the possible involvement of the Ep-CAM protein and bacteria of the Blautia genus in the mechanism of the influence of the FUT2 gene on intestinal diseases allows us to better understand the mechanism that leads to these gastrointestinal problems and to find possible solutions. This question will be a pretext for a new research, because so far scientists have discovered only a small piece of this complex mechanism that combines genetics, microbiome and proteins.