Behavior - it's all in our gut

Does the way we behave depend in part on the specific community of microbes living within each of us? Dr. Michael Montague studies the microbiome of a free-ranging population of primates to understand how it shapes their social interactions and vice versa. 

Good news was followed by a disaster. Just a few days after Michael Montague heard that he won the 2017 QIAGEN Microbiome Award, Hurricane Maria devastated much of Puerto Rico. The hurricane also swept over a small research island called Cayo Santiago, where scientists have been observing hundreds of rhesus macaque monkeys for decades. The island was the precise spot where Dr. Montague had planned to realize his project.

Meet Dr. Michael Montague, winner of the 2017 Microbiome Award to study the brain-gut network in free-ranging macaques.

Dr. Michael Montague of the University of Pennsylvania is the winner of the 2017 Microbiome Award. As an undergraduate at Boston College, he majored in biology and excelled in genetics and molecular biology. While contributing to research projects in wildlife biology, he became fascinated with topics in evolutionary biology and animal behavior. He obtained a doctoral degree in primatology and genetics from New York University, followed by a three-year postdoctoral position in genomics and computational biology at the McDonnell Genome Institute at Washington University’s School of Medicine.

Q. What can you tell us about the current situation on Cayo Island?

A. Fortunately, all of the monkeys survived the storm and its aftermath. But our entire research infrastructure was erased by the hurricane, all facilities were destroyed and are in need of rebuilding. We have begun raising funds for the long rebuilding process, but it will take several months until my research will be possible again.

Q. Why is this spot special?

A. The ancestors of these monkeys were originally moved to the island from India in 1938, making it one of the oldest primate research centers in the world. For eight decades and over nine generations, the births, deaths, and group dynamics have all been charted. This makes it an incredibly unique resource for understanding how they think, choose friends, choose mates, and the genetic underpinnings of their complex social behaviors.

Q. But how are monkeys connected to your field of research, the microbiome?

A. We want to test whether the microbiome and behavior influence each other. Monkeys live in large social groups of 80 to 300 animals. A number of social units, characterized by stable female family groups, exist in these groups. Male monkeys often move within and between different social groups. Our research team was already able to show that monkeys from different social groups show changes in their microbiomes.

Q. Is the microbiome linked to social behavior?

A. That is what studies on wild chimpanzees and baboons have shown. In humans, microbiome variation is also linked to health issues, such as obesity and autoimmune disorders. So different questions arise, including how might animals modify their behavior to maintain a healthy and diverse set of microbes. It’s likely that beneficial microbes provide animal hosts with the immunity and metabolism to forage and find mates, strengthen their social interactions with their preferred group mates, and – most importantly – avoid predators or other threats.

Q. So what will your QIAGEN-supported project look like?

A. Our proposal specifically examines how varying degrees of social interaction impact the gut microbiome in rhesus monkeys, while also exploring how the diversity of gut microbes influences levels of peripheral and central serotonin. Some species of gut bacteria can directly metabolize tryptophan, a crucial precursor used in the manufacture of serotonin. Competition for tryptophan is therefore likely to impact host serotonin availability.

Q. Why do you look at serotonin?

A. Serotonin is a key neurotransmitter influencing our digestive tract, cardiovascular system and our brain. It is known to play a role in modulating mood, appetite, sleep, cognition, arousal or pain – thus, it also has an important effect on behavioral patterns.

Q. Can you tell how your project will unfold?

A. We will first measure female grooming behavior, followed by shotgun sequencing of gut microbiomes from fecal samples and serotonin collection from various bodily fluids. We expect socially integrated females who interact more frequently in grooming to possess more diverse gut microbiomes and different levels of serotonin. Resulting data will enable us to clarify how the gut microbiome affects serotonin synthesis and the potential effects of serotonin and gut microbial composition on social behavior.

"The coevolution of hosts and their microbiome represents a complex and integrated arrangement."
Dr. Mike Montague, Post-Doctoral Researcher, Department of Neuroscience, University of Pennsylvania

Q. Do you see any implications of your research for humans?

A. We can use our findings in monkeys as a guidepost for understanding the biology of both normal and atypical human behavior. How exactly do our deeper and more numerous connections makes us healthier, happier, and live longer? Such knowledge may help design new treatments for human disorders. There’s, for instance, increasing evidence that changes in tryptophan or serotonin levels in the gut may be important for understanding disorders of the central nervous system.

Q. In your research you combine more traditional field research with modern molecular technologies. What kind of biologist are you?

A. As a student I carried out field research. But today I consider myself a computational biologist, so much of my time is spent working with and analyzing genomic data from our primate research population. We’ve recently generated some gene expression data from different types of tissues, including blood, and of course our team is heavily invested in developing more results from the data we generated from skin and fecal

Q. Do you use QIAGEN technology doing your work?

A. I made use of QIAGEN extraction kits throughout my graduate training. They were easy to use and produced quality template DNA from low-quality fecal samples collected in the field. Our current work on skin and fecal microbiomes makes use of the DNeasy Power Soil Kits.

Q. What is your ambition with this research?

A. The coevolution of hosts and their microbiome represents a complex and integrated arrangement. If we can illustrate a comprehensive picture of microbiome diversity within the context of a population’s social structure, then we might gain a better appreciation of being social as an evolutionary mechanism. I anticipate testing whether and how varying degrees of social integration impacts the microbiome and serotonin levels, since this represents a critical step in our understanding of the gut-brain axis.

Q. Do you find it more fascinating or more frightening that our behavior is possibly shaped by countless microorganisms in and around us?

A. I’m fascinated by this idea. This is really about the big question of how our brain processes information to elicit certain behaviors, specifically spontaneous behaviors such as laughing. How might our moods and reactions be shaped in part from viruses and bacteria? If you add the question about how different behaviors evolved in the first place, and ponder the microbiome’s role in all of this, then these are extremely exciting questions. Individuals and the microbiome influence each other mutually; we are part of one ecosystem.

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