Bacterium of the Month: Akkermansia muciniphila

We’re excited to bring you a new monthly series here at the uBiome Blog: Bacterium of the Month!

We hope you’ll join us as our laboratory team member, Akshaya Krishnan, shares her research with us. This month she focuses on a bacterium that has been getting a lot of attention lately.


Long live

Akkermansia muciniphila

Recent advances in microbiome sequencing and discovery technologies have resulted in a greater focus on the role played by different microorganisms in the human gut. Improper maintenance of one’s gut microbiota can lead to various diseases. One such microorganism that resides in the intestinal lining is Akkermansia muciniphila, a gram negative anaerobe [1].

Why does Akkermansia need your intestine?
Different regions of the intestine, although varying in their environmental conditions, have a mucous lining that covers the epithelial cells. Rich in mucin, this mucous layer acts as an adhesive surface for numerous microbes, facilitating host-microbe interactions. A. muciniphila, uses this mucin as its source of energy, thus colonizing the intestine and protecting the gut from pathogens by means of competitive exclusion [1]. This bacterium colonizes the human intestine at a very young age since it is found at low concentrations in breast milk and formula [2].

Utilizing mucin gives A. muciniphila an ecological advantage as it does not rely on the host for its nutrition, unlike many other microbes [1]. By utilizing the mucin reserves, they thrive even in the absence of nutrients in the gut (especially during fasting) [2]. 61 of the total genes in the Akkermansia genome are suggested to play a role in mucin degradation and gut environment adaptation [1].

Why do we need Akkermansia?
Akkermansia muciniphila is suspected to be involved in a mechanism that restores the intestinal mucin reserves, making them self-sufficient [2]. As mucin degrades, a variety of fermented products are released. Among these are Short Chain Fatty Acids (SCFA), known to serve as energy sources for neighboring bacteria. Acetate, a prominent SCFA released in the gut, is known to curtail weight gain by virtue of its anorectic effects. While the contribution of A. muciniphila towards acetate levels is unknown, published evidence suggests a strong correlation between its abundance and acetate levels [3]. This abundance in the intestine induces the expression of a protein FIAF (Fasting-Induced Adipose Factor) known to promote reduction of fat storage. Akkermansia also increases the expression of RegIII, a bactericidal lectin which specifically targets certain pathogenic species in the intestine [4].

Significance with respect to human health
A. muciniphila is considered to be the most abundant mucolytic (mucus degrading) bacteria in a healthy individual. A low concentration of this species in your gut could indicate a thin mucous layer, thereby resulting in a weakened gut barrier function, besides increased translocation of bacterial toxins. Patients suffering from Inflammatory Bowel Disease (IBD), obesity and Type II diabetes (T2D) tend to have lower concentrations of A. muciniphila [5]. Its concentration is also known to decrease with age [2]

Let’s have some Akkermansia for lunch!
It is understood that oral consumption of live Akkermansia spp. (tested on mice) may prevent diet-induced obesity by means of altering the adipose tissue metabolism and gut permeability without affecting appetite and food habits. As impressive as its properties are, the administration of this bacterium on humans is still under investigation owing to safety concerns [6].

An alternative to the direct intake of live A. muciniphila is the consumption of polyphenol-rich foods. Administration of polyphenol to obese mice has shown to reduce the detrimental effects of obesity and increase Akkermansia abundance. Cranberries contain Proanthocyanidins (PAC), a polyphenol, which has a prebiotic effect on Akkermansia. PAC facilitates the differentiation of goblet cells (found in the epithelial lining of certain organs) which in turn produce mucus, thus providing an environment for A muciniphila to thrive. PAC rich cranberries might be an excellent therapeutic alternative to improve Akkermansia abundance [7].

Not only does the existence of Akkermansia illustrate a thriving host-microbe relationship, its anti-obesity properties makes it an excellent candidate bacterium to be examined further in our fight to tame obesity and T2D.

Long live Akkermansia!

References:

1. Belzer, C., & de Vos, W. M. (2012). Microbes inside—from diversity to function: The case of Akkermansia. The ISME Journal, 6(8), 1449–1458. Article

2. Derrien, M., Belzer, C., & de Vos, W. M. (2015). Akkermansia muciniphila and its role in regulating host functions. Microbial Pathogenesis. Article

3. Dao, M. C., Everard, A., Aron-Wisnewsky, J., Sokolovska, N., Prifti, E., Verger, E. O., … Clément, K. (2015). Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology. Gut, 1–11. Article

4. Anhê, F. F., Varin, T. V., Le Barz, M., Desjardins, Y., Levy, E., Roy, D., & Marette, A. (2015). Gut Microbiota Dysbiosis in Obesity-Linked Metabolic Diseases and Prebiotic Potential of Polyphenol-Rich Extracts. Current Obesity Reports, 389–400. Article

5. Brahe, L. K., Le Chatelier, E., Prifti, E., Pons, N., Kennedy, S., Hansen, T., … Larsen, L. H. (2015). Specific gut microbiota features and metabolic markers in postmenopausal women with obesity. Nutrition & Diabetes, 5(6), e159. Article

6. Shen, J., Tong, X., Sud, N., Khound, R., Song, Y., Maldonado-Gomez, M. X., … Su, Q. (2016). Low-Density Lipoprotein Receptor Signaling Mediates the Triglyceride-Lowering Action of Akkermansia muciniphila in Genetic-Induced HyperlipidemiaHighlights. Arteriosclerosis, Thrombosis, and Vascular Biology, 36(7), 1448–1456. Article

7. Anhê, F. F., Varin, T. V., Le Barz, M., Desjardins, Y., Levy, E., Roy, D., & Marette, A. (2015). Gut Microbiota Dysbiosis in Obesity-Linked Metabolic Diseases and Prebiotic Potential of Polyphenol-Rich Extracts. Current Obesity Reports, 389–400. Article


About the author:
Akshaya Krishnan is a member of the growing uBiome Laboratory Team. She firmly believes the next big revolution in healthcare will come from a personalized understanding of the human microbiome. She holds a MS in Biotechnology from the University of Melbourne and has an avid interest in microbiology and science communication. She is a die-hard Harry Potter fan and in her spare time, she loves to cook different cuisines. Find Akshaya on Twitter at @akshkrishnan.