First Autograph Goes to Our First and Fast Friends-Bacteria

Azam Ali Sher | Michigan State University |CMIB & EITS Graduate Program

First Autograph Goes to Our First and Fast Friends-Bacteria

Did you know that you had millions of friends with you the moment you were born? On the day of birth, we all immediately meet these new friends – bacteria. We carry these bacteria in and on our bodies all the time and build a strong mutual bond that lasts throughout life. The consortium of these bacteria, along with other microbes (viruses and fungi), is called the “human microbiota.” In general, the body is made up of more bacterial cells than human cells; that is why it is stated: “We are more microbes than humans.”

The human microbiota is divided into categories based on location, such as skin, oral, lung, vaginal, and gut microbiota. All these different human microbiotas are unique and different from each other in terms of the diversity and composition of the bacterial community (1,2). However, the gut microbiota is especially fascinating because it has shown a significant impact on multiple physiological functions in the body, such as metabolism, nervous system, immunity, growth, and development.

Gut microbiota is a complex community of around ten-to-one hundred trillion (10¹³– 10¹⁴) microbial cells made up of 500 to 1000 different species (1). When we are born, we get a few types of these valuable and mutually beneficial bacteria, known as commensal bacteria. Over time, this bacterial community grows and eventually reaches a stable equilibrium state. Gut microbiota is considered a forgotten organ, yet it regulates multiple essential bodily functions: digestion of food, production of vital vitamins (B12, K, riboflavin, and thiamine), modulation of the immune system, and protection from pathogenic bacteria. The gut microbiota also influences distant organs in the body, such as the lung, liver, and brain.

In the gut, there are millions of bacteria living close to human intestinal epithelial cells. Any disruption in these interactions and/or the equilibrium of the gut microbiota leads to leads to the development of multiple inflammatory, autoimmune, and neurological diseases, including inflammatory bowel disease, colorectal cancer, obesity, and Clostridium difficile infection (3). To develop effective therapeutics against these diseases, there is a dire need to investigate the underlying mechanisms of microbe-microbe, microbe-host, and microbe-host-environment interaction. In addition, scientists are still investigating how this balance and interaction between the complex microbial community and your gut is maintained without causing harm to each other.”

Furthermore, the gut microbiota is known as a factory of metabolites (small molecules secreted by bacteria). These metabolites are involved in regulating vital signaling and metabolic pathways in the body. The secretion of different molecules from gut microbiota also protects the epithelial surface of the gut. Additionally, the gut microbiota has the potential to aid the discovery of novel therapeutics, prebiotics, and probiotics to treat multiple life-threatening diseases (3). There are potentially many more essential molecules that remain undiscovered to date. Another exciting role of the gut microbiota is colonization resistance—the gut microbiota limits bacterial growth of harmful invading pathogens, helping to keep you healthy and avoid infections. However, dysbiosis in the gut microbiota will result in the disrupted production of these vital molecules and loss of friendly bacteria, ultimately causing serious health consequences.

Genetics, lifestyle and the environment collectively impact the human gut microbiota. Diet is considered a pivotal player that shapes the gut microbial community over time. Different studies have shown the effect of Western, Mediterranean, and Asian diets on the development and composition of the gut microbiota. However, more robust studies are required to establish a causal relationship. Hippocrates said once, ‘all disease begins in the gut…., and let food be thy medicine.” Overall, recent studies show that a person’s good health is directly linked with healthy gut microbiota.

Microbiome research is at the early stages with many new and impactful medical research questions that still need to be addressed. There is an increasing demand for young scientists to initiate and join research endeavors to investigate the role of the gut microbiota on human health. Also, there are multiple opportunities for research collaboration because microbiome research requires a transdisciplinary approach and team that includes biologists, data scientists, health, and social sciences. Let us keep learning more and more about our friend commensal bacteria and improve human health through novel discoveries.

References:

1. Turnbaugh PJ, Ley RE, Hamady M, et al. The Human Microbiome Project. Nature. 2007;449(7164):804–810.

2. Costello EK, Lauber CL, Hamady M, et al. Bacterial community variation in human body habitats across space and time. Science (80-. ). 2009;326(5960):1694–1697.

3. Kho ZY, Lal SK. The human gut microbiome – A potential controller of wellness and disease. Front. Microbiol. 2018;9(AUG):1–23.

Autograph to friend commensal E. coli bacteria