Genetec Engineering and Biotechnology News recently carried a story giving credit to Baylor College researchers for finding microbes living in the gut that are associated with specific symptoms of neurological disorders.
Many neurological disorders have traditionally associated genetics as being the cause of brain function and development. But recent findings indicate a gut-brain connection.
About the Gut Microbiome
Thus far studies of the gut microbiomes have been conducted primarily in mice to determine whether there is therapeutic potential.
The gut microbiome consists of microorganisms such as viruses, bacteria, fungi, and protozoa. It also includes genetic material that exists in the gastrointestinal tract.
The Baylor study, which was published by Cell, analyzes the microbiome’s role in complicated behaviors. Microbes, which cannot be seen with the naked eye, may either be harmful or else they can be important to our health.
Studies indicate that the microbiome interacts with the nervous system and releases molecules that may travel to the brain. Microbiota, by sending signals to the brain, regulates central nervous system development and inflammation. It also affects behavior and mood.
Social Behavior vs. Neurodevelopmental Disorders
To be specific, the Baylor team found that when analyzing neurodevelopmental disorders, hyperactivity is regulated by genetics.
On the other hand, social behavior is controlled by the gut microbiome which has been proven to impact complex behavior.
The team noticed an improvement in social behavior (but not motor activity) when the Cntnap2 mice were treated in the gut with a protein-producing compound in the biopterin family. Biopterin is a requirement for synthesizing serotonin (a neurotransmitter).
The Baylor researchers were surprised to learn that dysfunctional behaviors are controlled by both the microbiome and the genes in Cntnap2 in which miRNAs (host genes) are embedded. The Cntnap2 gene, one of the largest in the human genome, has been associated with autism spectrum disorders (ASD).
The team also found it interesting that certain microbial interventions (procedures) repaired the social deficiencies in Cntnap2 mice.
Findings by scientists at the Costa-Mattioli lab indicate that although the focus to date has been on host genes, the gut microbiome, which are microorganisms that live in the human body, represents another source of genetic information.
The Costa-Mattioli study suggests a new approach to neurological disorders. In this scenario, the interaction of both the microbial and human genes contributes to a condition. In addition, in order for a treatment to address each symptom, it would have to be directed at both the gut and the brain.
Sean Dooling, co-author and Ph.D. candidate at the Costa-Mattioli lab, explained how it is difficult to analyze these interactions in a human. For that reason, in working with neurodevelopmental disorders, the team used a mouse model in which both copies of the Cntnap2 gene were missing.
The researchers observed hyperactivity and social deficiencies which had also been found in ASD. When compared to the mice that did not have genetic variants, the socially deficient mice exhibited changes in the bacteria within their microbiome.
The scientists agree that additional trials and research are needed in order to have a better understanding of the relationship between the brain and the gut. Yet they feel confident that the trials already in progress will eventually lead to therapies for neuropsychiatric disorders.