This blog post provided by guest blogger Kristine Klos, PhD, Minnesota Department of Health
I had the pleasure of attending the Frontiers for Toxicology Session, Bugs to Drugs: The Microbiome in Human Health, Disease, and Therapeutics on Tuesday morning. Mark Adams of the J. Craig Venter Institute, Rob Knight of the University of California - San Diego, Pieter Dorrestein of the University of California - San Diego, and Jeremy Nicholson of the Imperial College London introduced the audience to the vast and complex world of the human microbiome.
The human microbiome consists of all the microorganisms that reside in or on our bodies. This includes over 10,000 species of bacteria that encode more than a million genes. Bacteria, fungi, and viruses that inhabit humans outnumber human cells by a ratio of 10:1 and weigh approximately three pounds. This large community of microorganisms is essential for our health, as perturbations are often linked with disease.
The major theme that recurred throughout the presentations of the morning was the awesome variability of the microbiome between various populations around the world, within human populations themselves, and among the various organs or sites of the human body. The human microbiome becomes even more complex when we consider that the variety of microorganisms changes over a human life-span, and is determined by our age, environment, physical activity, diet, previous exposure to antibiotics, etc.
An individual’s microbiome may be assessed through urine, fecal matter, saliva, or by a skin swab. Identification of the biota making up a person’s microbiome is determined by RNA sequencing. Metabolites produced from the organisms can be assessed by mass spectrometry. This information is entered into global databases that can aid research from a wide variety of scientific fields.
The potential impact of knowing a person’s individual microbiome is enormous, particularly with regards to personalized health care. Research is underway to predict toxicity outcomes for drugs, to predict who will respond to a certain drug, how an individual may metabolize a certain drug, and whether we can alter an individual’s microbiome to respond to a drug. We can even take this down to a molecular level and look at a person’s microbiomic metabolites. A loss of a sugar group here, or a sulfate group there on a metabolite can change the way one responds to a drug or enhances the resistance to an antibiotic. Inhibiting or adding a bacterial enzyme could enhance a drug’s efficacy or limit toxicity. Along a similar vein, we might also be able to predict the potential metabolic response of an individual or a population exposed to an environmental chemical, and formulate a plan to mitigate risk. This is currently an under-explored area of research.
I was fascinated to find out that wherever we go, we leave behind our own personal microbiota tracking device. Just as a fingerprint or DNA can identify an individual from a population, so too, can a person’s individual microbiome. We leave a bit of ourselves behind when we touch a computer keyboard or answer a phone. The object can be swabbed, the microbiota sequenced or the metabolites analyzed, and an individual identified. This could find application in the field of criminology and forensics. Current research is underway to assess the microbiome of decaying bodies and the soil microbes surrounding it.
As a new frontier in toxicology, the field of microbiome research is in its infancy and has huge potential for affecting our lives in the future. It was fitting that the overview of the human microbiome be introduced to some of us, today, as we will no doubt cross paths with this field of research in our careers or reap the research benefits in our personal lives.
This blog discusses highlights from the SOT Annual Meeting and ToxExpo Frontiers for Toxicology Session, Bugs to Drugs: The Microbiome in Human Health, Disease, and Therapeutics