News

How microbes in a mother s intestines affect fetal neurodevelopment

How microbes in a mother s intestines affect fetal neurodevelopment
Science
During pregnancy in mice, the billions of bacteria and other microbes that live in a mother s intestines regulate key metabolites, small molecules that are important for healthy fetal brain development, UCLA biologists report Sept. 23 in the journal Nature.

advertisement

While the maternal gut microbiota has been associated with abnormalities in the brain function and behavior of offspring -- often in response to factors like infection, a high-fat diet or stress during pregnancy -- scientists had not known until now whether it influenced brain development during critical prenatal periods and in the absence of such environmental challenges.

To test the impact the gut microbiata has on the metabolites and other biochemicals that circulate in maternal blood and nurture the rapidly developing fetal brain, the researchers raised mice that were treated with antibiotics to kill gut bacteria, as well as mice that were bred microbe-free in a laboratory.

"Depleting the maternal gut microbiota, using both methods, similarly disrupted fetal brain development," said the study s lead author, Helen Vuong, a postdoctoral scholar in laboratory of UCLA s Elaine Hsiao.

Depleting the maternal gut microbiota altered which genes were turned on in the brains of developing offspring, including many genes involved in forming new axons within neurons, Vuong said. Axons are tiny fibers that link brain cells and enable them to communicate.

In particular, axons that connect the brain s thalamus to its cortex were reduced in number and in length, the researchers found.

advertisement

"These axons are particularly important for the ability to sense the environment," Vuong said. "Consistent with this, offspring from mothers lacking a gut microbiota had impairments in particular sensory behaviors."

The findings indicate that the maternal gut microbiota can promote healthy fetal brain development by regulating metabolites that enter the fetal brain itself, Vuong said.

"When we measured the types and levels of molecules in the maternal blood, fetal blood and fetal brain, we found that particular metabolites were commonly decreased or missing when the mother was lacking a gut microbiota during pregnancy," she said.

The biologists then grew neurons in the presence of these key metabolites. They also introduced these metabolites into the microbiata-depleted pregnant mice.

"When we grew neurons in the presence of these metabolites, they developed longer axons and greater numbers of axons," Vuong said. "And when we supplemented the pregnant mice with key metabolites that were decreased or missing when the microbiata was depleted, levels of those metabolites were restored in the fetal brain and the impairments in axon development and in offspring behavior were prevented.

advertisement

"The gut microbiota has the incredible capability to regulate many biochemicals not only in the pregnant mother but also in the developing fetus and fetal brains," Vuong said. "Our findings also pinpoint select metabolites that promote axon growth."

The results suggest that interactions between the microbiota and nervous system begin prenatally through the influence of the maternal gut microbiota on the fetal brain, at least in mice.

The applicability of the findings to humans is still unclear, said the study s senior author, Elaine Hsiao, a UCLA associate professor of integrative biology and physiology, and of microbiology, immunology and molecular genetics in the UCLA College.

"We don t know whether and how the findings may apply to humans," said Hsiao, who is also an associate professor of digestive diseases at the David Geffen School of Medicine at UCLA. "However, there are many neurodevelopmental disorders that are believed to be caused by both genetic and environmental risk factors experienced during pregnancy. Our study suggests that maternal gut microbiota during pregnancy should also be considered and further studied as a factor that could potentially influence not only the health of the mother but the health of the developing offspring as well."

Hsiao, Vuong and colleagues reported in 2019 that serotonin and drugs that target serotonin, such as antidepressants, can have a major effect on the gut s microbiota. In 2018, Hsiao and her team established a causal link between seizure susceptibility and gut microbiota and identified specific gut bacteria that play an essential role in the anti-seizure effects of the ketogenic diet.

Materials provided by . Original written by Stuart Wolpert. Note: Content may be edited for style and length.

University of California - Los Angeles. "How microbes in a mother s intestines affect fetal neurodevelopment." ScienceDaily. ScienceDaily, 23 September 2020. .

University of California - Los Angeles. "How microbes in a mother s intestines affect fetal neurodevelopment." ScienceDaily. www.sciencedaily.com/releases/2020/09/200923164601.htm (accessed September 23, 2020).

advertisement

1

Sep. 6, 2019 — A new study in mice strongly suggests that serotonin and drugs that target serotonin, such as anti-depressants, can have a major effect on the gut s microbiota -- the 100 trillion or so bacteria ...

Jan. 17, 2019 — Recent studies have shown that maternal gut microbiota in humans primes the offspring s immune and metabolic development during pregnancy and lactation. Due to environmental factors that are ...

Dec. 19, 2017 — Our gut hosts a community of trillions of microbes, called the gut microbiota, and we are becoming increasingly aware that this has significant effects on many aspects of our health. However, the ...

Jan. 13, 2016 — Gut microbes are well known to contribute to health and disease, but what has been less clear is how the host controls gut microbes. A study now reveals that mice and humans produce small molecules ...
Read more on sciencedaily.com
News Topics :
RELATED STORIES :
Science
One type of gut bacteria makes a huge difference when it comes to initiating social interactions between mice. stock image The researchers believe that their work, which uses a human...
Science
Plant products ingested by pregnant women through their diet are broken down by the intestinal microbiota into chemical substances, some of which can cross the placental barrier and reach the...
Science
The balance between omega 6 and omega 3 fatty acids in the tissues of female mammals, which previous research has suggested can impact the incidence of obesity in their offspring, appears to...
Science
A new study by researchers at UCLA has revealed two key findings for people with irritable bowel syndrome about the relationship between the microorganisms that live in the gut and...
Science
Exposure to microbiota, or microorganisms such as bacteria, in the early stages of life plays a crucial role in establishing optimal conditions in the intestine that inhibit the development of...