Cesar de la Fuente ‘Trends in Immunology’ Literature Review

by Sophie Burkholder


Cesar de la Fuente, PhD

Cesar de la Fuente, Ph.D., a Presidential Assistant Professor in Psychiatry, Microbiology, and Bioengineering at Penn, recently published a literature review in Trends in Immunology entitled, “Emerging Frontiers in Microbiome Engineering.” The microbiome, in simple terms, consists of the genetic material of microorganisms in the gut, including bacteria, fungi, protozoa,  viruses, and oral, vaginal, and skin microbiomes. Each human has a unique microbiome that depends both on predetermined factors like exposure to microorganisms within a mother’s birth canal or breastmilk in early life as well as environmental factors and diet in later life. The health of someone’s microbiome is extremely important, as an unhealthy microbiome with an imbalance of symbiotic and pathogenic microbes can make a person more susceptible to various diseases. The most common diseases or disorders associated with a problematic microbiome are rather far-reaching, including some of the most afflicting diseases of today like inflammatory bowel disease, diabetes, obesity, cardiovascular diseases, and neurological disorders.

In his recent literature review, de la Fuente provides an overview of microbiome engineering, and what the future might hold for the field. He defines microbiome engineering initially as a way of studying the “contribution of individual microbes and generating potential therapies against metabolic, inflammatory, and immunological diseases.” Currently, most treatments for issues with the microbiome are broad solutions like dietary adjustments to include more probiotics, antibiotics, or prebiotics, while more serious cases may require a fecal microbiota transplant. While these therapies may work for some patients, de la Fuente emphasizes the need for greater specificity in treatment targets and a need for precision in reprogramming existing microbial communities as an alternative to transplants.

De la Fuente highlights the current methods and tools in microbiome engineering such as the use of bacteriocins and bacteriophages to knock out specific bacteria within the microbiome. However, there are very few bacteriocins or bacteriophages commercially available on today’s market. Another common approach to microbiome engineering is in synthetic biology, or the use of “chassis” — a type of cell that maintains DNA constructs for different functions — to engineering interactions within the microbiome. De la Fuente continues his discussion of current methods by naming and describing several specific examples of these approaches, particularly in relation to synthetic biology options before moving on to examine future directions for these methods.

Before bringing up potential new frontiers for microbiome engineering, de la Fuente also outlines the way that microbiome engineering works in the first place, and dedicates sections of the review to the microbiome’s influence on its host’s immune system and how to engineer the microbiome to modulate that immune system. The main future methods for microbiome engineering that de la Fuente points out in his review include more precise regulation of gene expression through commensal organisms and the use of CRISPRi to find genes involved in bacterial maintenance. The conclusion of de la Fuente’s review brings up the notion of new personalized medicine or therapy for the microbiome that could come with further advances in the field. However, he also makes sure to bring up some still-outstanding questions about the human microbiome that require further research, most notably, what exactly makes a healthy human microbiome? Here’s hoping the research de la Fuente mentions can illuminate a path to the answer.