Team:Baltimore BioCrew/Description

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DESCRIPTION & INSPIRATION

• Inspiration






• MAFFs






• Solution

Inspiration

According to the CDC, 5 out of 6 Americans are prescribed antibiotics every year (CDC, 2017). These antibiotics, while often lifesaving, can also lead to severe unintended health consequences. These consequences are known all too well not only by people everywhere, but even to a member of our own team...

Prescribed antibiotics to cure a simple infection, a fellow Baltimore Bio-Crewer had been optimistic, hoping that the round doctor-sanctioned pills could relieve her of her ailment. The symptoms ceased but then re-occurred. The diagnosis? Another infection. The prescription? More antibiotics. However, the second "infection" was a misdiagnosis, leading to weeks of unnecessary antibiotics, intestinal aggravation, and pain.

Antibiotics kill or slow the growth of any bacteria they encounter by destroying the cell wall or inhibiting protein synthesis and reproduction. However, antibiotics do not only kill the pathogens they were prescribed to destroy. Instead, they kill and destroy billions of other endemic bacteria that live peacefully in our gut. These non-pathogenic, helpful bacteria are a part of our microbiome. They provide a range of functions such as digesting food, controlling the immune system, synthesizing needed vitamins, and producing neurotransmitters (LeBlanc et al., 2012).

Antibiotics can decrease gut diversity by more than 25 percent, throwing the microbiome out of balance (Dethlefsen et al., 2008;Francino, 2016). This can lead to a range of health issues, including colitis, irritable bowel syndrome, and Crohn’s disease, while also increasing the risk for future infections by weakening the immune system and giving pathogens the space to grow (Shaw et. al, 2011). This issue is incredibly important, but unfortunately, it does not get the attention it deserves. So, we decided to use synthetic biology to do something about it, aiming to help fellow humans both on our team and around the world.

During our research, we came across a paper from the Journal of Experimental Medicinethat detailed the effects of two genes found in Bacteroides thetaiotaomicron. These genes not only aid the bacteria in nutrient uptake but also have a known correlation between their expression and the diversity of the surrounding microbial environment. This seemed like a good area to research, as it has direct practical applications and only requires the overexpression of these two genes in an alternate bacterial species.

Thus, our goal was established: to repopulate the microbiome after antibiotic treatment which in turn, will fortify the gut against bacterial disease.

MAFF

The two genes (BT2268 and BT2269) produce two proteins known as Mucus Associated Functional Factors (MAFFs). In our body, MAFF proteins promote microbiome diversity and epithelial cell health. However, B. theta, the bacterium that produces MAFFs is easily destroyed by antibiotics. Thus, antibiotics reduce MAFF production, creating a negative feedback loop that prevents the re-establishment of a healthy gut.

Solution

Our Solution: MAFF producing Probiotics
By introducing E. coli that has been engineered to produce MAFFs into the gut, along with a xylose supplement, a stable microbiome could be regrown. This is achieved by altering the B. theta MAFF-producing gene and inserting it into a plasmid that will be uptaken by E. coli. As the E.Coli arrive in the gut, they will begin to produce MAFF proteins, thus encouraging the recolonization of the gut and improving overall gut health.
Because the bacteria will be delivered inside the human body, it is imperative that they contain a killswitch. This will prevent them from overpopulating and unbalancing the gut. Our killswitch releases a toxin when the bacteria are deprived of xylose. Once the bacteria use up their xylose supplement, they will die, but even with a short life expectancy, the E. coli will provide the MAFF needed to jump-start the reestablishment of a healthy microbiome.

Sources

CDC: 1 in 3 antibiotic prescriptions unnecessary | CDC Online Newsroom | CDC. (2016, January 1). Retrieved from https://www.cdc.gov/media/releases/2016/p0503-unnecessary-prescriptions.html.

Dethlefsen L., Huse S., Sogin M. L., Relman D. A. (2008). The pervasive effects of an antibiotic on the human gut microbiota, as revealed by deep 16S rRNA sequencing. PLoS Biol. 6:e280 10.1371/journal.pbio.0060280

Francino M. P. (2016). Antibiotics and the Human Gut Microbiome: Dysbioses and Accumulation of Resistances. Frontiers in microbiology, 6, 1543. doi:10.3389/fmicb.2015.01543

Nakajima, A., Vogelzang, A., Maruya, M., Miyaajima, M., Murata, M.,...Suzuki, K. (2018). IgA regulates the composition and metabolic function of gut microbiota by promoting symbiosis between bacteria. Journal of Experimental Medicine,215 (8) 2019-2034; DOI: 10.1084/jem.20180427

LeBlanc, J.G., Milani, C, de Giori, GS, Sesma, F, van Sinderen, D, Ventura M. (2012). Bacteria as vitamin suppliers to their host: a gut microbiota perspective. Curr Opin Biotechnol. 24(2).160-8. doi: 10.1016/j.copbio.2012.08.005

Shaw, S., Blanchard, J., Bernstein, C. Association Between the Use of Antibiotics and New Diagnoses of Crohn's Disease and Ulcerative Colitis. (2011)American Journal of Gastroenterology. 106(12):2133–2142. DOI: 10.1038/ajg.2011.304