Mikael Niku’s team studies foetuses and how the body’s microbiota develops after birth. Niku is especially interested in how the mother’s microbiota affects the foetal development and immune system in different mammals.
It is a long-established fact that after birth, microbes in the mothers’ body are passed on to the offspring. This prepares the child for life outside the womb.
“The mother’s microbiota also affects immune system development. The immune system learns to accept beneficial gut microbes and to fight pathogens. A diverse microbiota will naturally ward off pathogens,” says Mikael Niku, Associate Professor at the Developmental Interaction Lab at the University of Helsinki.
Niku’s aim is to determine the kinds of mechanisms the maternal microbes use to modulate the development of the immune system of the offspring. His research group carries out data analyses using the equipment of the CSC – IT Center for Science, the Finnish ELIXIR node.
The research involves analysing microbiomes using amplicon sequencing, targeting the 16S ribosomal RNA (rRNA) gene region. This makes it possible to study the microbiota composition. The 16S gene regions are sequenced and identified through publicly accessible databases.
A large proportion of the immune system’s cells are in the intestines. They develop from blood stem cells, taking the form of different types of white blood cells. Diet, lifestyle and the medicines a person takes and the chemicals in their environment all affect the intestinal microbiota. The microbes process the substances our bodies absorb, turning them into metabolites.
“In the past, our group – like many other research groups – focused on investigating whether maternal bacteria are transferred from the mother to the foetus. After all, almost no living bacteria is present in a healthy foetus. However, we now know that microbes produce small-molecule metabolites that are then transferred to the foetus.”
Niku is interested in finding out what sort of metabolites are transferred to foetuses and how these metabolites affect the foetal development.
“The metabolites are absorbed from the gut into the bloodstream, from where they’re transferred to placenta and to the foetus. We found that the concentrations of some metabolites are associated to the functioning of genes in the foetus. These genes are often linked to the immune system and its development.”
One thing that Niku’s research group is currently studying is extracellular vesicles that are produced by bacteria. Vesicles are small, liquid-filled sacs of membrane that are produced by both animal and bacterial cells. They are found in all bodily fluids. Although vesicles were discovered as early as 1946, research on them took off in earnest only in the 2000s. Vesicles contain various cellular products.
“Vesicles may play an important role in things such as recycling materials in the body, cell-to-cell communication, immune regulation and various diseases, among other things.”
Researchers at the University of Oulu were the first team in the world to publish a study that showed that vesicles are transferred from the maternal microbiota to the foetus. They discovered a previously unknown interaction mechanism between the maternal microbiota and the developing foetus.
Niku and his team is further investigating how the foetal immune system develops before birth. Is recognising the good bacteria that the body should not attack something that the foetus’ immune system learns already at this stage?
“It’s possible that vesicles carry bacterial macromolecules, such as proteins, into the foetus, thus training its immune system to discern good bacteria from pathogens. This would allow the offspring to recognise the gut microbes of their mother or their species prior to birth.”
The team’s next focus is on how vesicles present in foetal tissues, how they are able to pass through the placenta and how they affect the foetus.
According to Niku, before long, it can be determined what kind of bacteria and bacterial products the foetus needs to develop an optimal immune system.
“For example, it could allow us to develop probiotic products that contain necessary microbes or microbial products that are currently unavailable.”
Ari Turunen
14.11.2024
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More information:
Developmental Interaction Lab at the University of Helsinki.
https://www.helsinki.fi/en/researchgroups/developmental-interactions
CSC – IT Center for Science
is a non-profit, state-owned company administered by the Ministry of Education and Culture. CSC maintains and develops the state-owned, centra- lised IT infrastructure.
https://research.csc.fi/cloud-computing
ELIXIR
builds infrastructure in support of the biological sector. It brings together the leading organisations of 21 Euro- pean countries and the EMBL European Molecular Biology Laboratory to form a common infrastructure for biological information. CSC – IT Center for Science is the Finnish centre within this infrastructure.
ELIXIR is partly funded by the European Commission