Penn Engineering and Stanford researchers leveraged AI to discover dozens of potential new antibiotics in the human gut microbiome. (ChrisChrisW via Getty Images)
The average human gut contains roughly 100 trillion microbes, many of which are constantly competing for limited resources. “It’s such a harsh environment,” says César de la Fuente, Presidential Assistant Professor in Bioengineering and in Chemical and Biomolecular Engineering within the School of Engineering and Applied Science, in Psychiatry and Microbiology within the Perelman School of Medicine, and in Chemistry within the School of Arts & Sciences. “You have all these bacteria coexisting, but also fighting each other. Such an environment may foster innovation.”
In that conflict, de la Fuente’s lab sees potential for new antibiotics, which may one day contribute to humanity’s own defensive stockpile against drug-resistant bacteria. After all, if the bacteria in the human gut have to develop new tools in the fight against one another to survive, why not use their own weapons against them?
In a new paper in Cell, the labs of de la Fuente and Ami S. Bhatt, Professor in Medicine (Hematology) and Genetics at Stanford, surveyed the gut microbiomes of nearly 2,000 people, discovering dozens of potential new antibiotics. “We think of biology as an information source,” says de la Fuente. “Everything is just code. And if we can come up with algorithms that can sort through that code, we can dramatically accelerate antibiotic discovery.”
Almost a century ago, the discovery of antibiotics like penicillin revolutionized medicine by harnessing the natural bacteria-killing abilities of microbes. Today, a new study co-led by researchers at the Perelman School of Medicine at the University of Pennsylvania suggests that natural-product antibiotic discovery is about to accelerate into a new era, powered by artificial intelligence (AI).
The study, published in Cell, the researchers used a form of AI called machine learning to search for antibiotics in a vast dataset containing the recorded genomes of tens of thousands of bacteria and other primitive organisms. This unprecedented effort yielded nearly one million potential antibiotic compounds, with dozens showing promising activity in initial tests against disease-causing bacteria.
“AI in antibiotic discovery is now a reality and has significantly accelerated our ability to discover new candidate drugs. What once took years can now be achieved in hours using computers” said study co-senior author César de la Fuente, PhD, a Presidential Assistant Professor in Psychiatry, Microbiology, Chemistry, Chemical and Biomolecular Engineering, and Bioengineering.
Nature has always been a good place to look for new medicines, especially antibiotics. Bacteria, ubiquitous on our planet, have evolved numerous antibacterial defenses, often in the form of short proteins (“peptides”) that can disrupt bacterial cell membranes and other critical structures. While the discovery of penicillin and other natural-product-derived antibiotics revolutionized medicine, the growing threat of antibiotic resistance has underscored the urgent need for new antimicrobial compounds.
In recent years, de la Fuente and colleagues have pioneered AI-powered searches for antimicrobials. They have identified preclinical candidates in the genomes of contemporary humans, extinct Neanderthals and Denisovans, woolly mammoths, and hundreds of other organisms. One of the lab’s primary goals is to mine the world’s biological information for useful molecules, including antibiotics.
Perelman School of Medicine’s Maayan Levy, and Christoph Thaiss. (Image: Courtesy of Penn Medicine News)
When we hear about gut bacteria, we may think about probiotics and supplements marketed to help with digestion, about how taking antibiotics might affect our intestinal tract, or perhaps about trendy diets that aim to improve gut health.
But two researchers at Penn Medicine think that understanding the microbiome, the entirety of microbial organisms associated with the human body, might be the key to deciphering the fundamental mechanisms that make our bodies work. They think these microbes may work like a call center switchboard, making connections to help different organs, biological systems, and the brain communicate. Maayan Levy, and Christoph Thaiss, both assistant professors of microbiology at the Perelman School of Medicine, argue that the microbiome is instrumental to revealing how signals from the gastrointestinal tract are received by the rest of the body—which may hold the key to understanding inter-organ communication in general. Perelman School of Medicine’s Maayan Levy, and Christoph Thaiss. (Image: Courtesy of Penn Medicine News)
While the gut sends signals to all parts of the body to initiate various biological processes, the mechanisms underlying this communication—and communication between different organs involved in these processes—is relatively unknown.
“The more we learn about the role the microbiome plays in a wide range of diseases— from cancer to neurodegenerative diseases to inflammatory diseases—the more important it becomes to understand what exactly its role is,” says Thaiss. “And hopefully once we understand how it works, we can use the microbiome to treat these diseases.”
Levy and Thaiss joined the faculty at Penn Medicine after completing their graduate studies in 2018. Here, they continue to investigate the role of the microbiome in various biological processes.
In his lab, Thaiss focuses on the impact of the microbiome on the brain. He recently identified species of gut-dwelling bacteria that activate nerves in the gut to promote the desire to exercise. Most recently, Thaiss published a study that identified the cells that communicate psychological stress signals from the brain to the gastrointestinal tract, and cause symptoms of inflammatory bowel disease.
Meanwhile, in her lab, Levy examines how the microbiome influences the development of diseases, like cancer, and other conditions throughout the body.
A recent publication authored by Levy suggested that the ketogenic diet (high fat, low carbohydrate) causes the production of a metabolite called beta-hydroxybutyrate (BHB), that suppresses colorectal cancer in small animal models.
Now, Levy is collaborating with Bryson Katona, an assistant professor of Medicine in the division of gastroenterology who specializes in gastrointestinal cancers, to investigate whether BHB has the same effect in patients with Lynch syndrome, which causes individuals to have a genetic predisposition to many different kinds of cancer, including colon cancer. These efforts are part of a growing emphasis at Penn on finding methods to intercept cancer in its earliest stages.
“It’s remarkable that we were able to quickly take the findings from our animal models and rapidly design a clinical trial,” Levy says. “One of the most exciting aspects of our work is not only making discoveries about how our bodies work on a biological level, but then being able to work with the world’s leading clinical experts to translate these discoveries into therapies for patients.”
Further, studies led by Levy and Thaiss often utilize human samples and data from the Penn Medicine BioBank, to validate animal model findings in the tissue of human patients suffering from the diseases which they are investigating.
While Levy and Thaiss pursue different research interests with their labs, they also collaborate often, building on their previous research into what the microbiome does, and its role in the biological processes that keep us healthy. Their long-term goal is to learn about the mechanisms by which the gastrointestinal tract influences disease processes in other organs to treat various diseases of the body using the gastrointestinal tract as a noninvasive entry point to the body.
“Some of the most common and devastating diseases in humans—like cancer or neurodegeneration—are difficult to treat because they are no existing therapies that can reach the brain,” says Thaiss. “If we can understand how the gastrointestinal tract interacts with other organs in the body, including the brain, we might be able to develop treatments that ‘send messages’ to these organs through the body’s natural communication pathways.”
“Obviously there is a lot more basic biology to be uncovered before we get there,” adds Levy. “Most importantly, we want to map all the different routes by which the gastrointestinal tract interacts with the body, and how that communication happens.”
Christopher Thaiss is Assistant Professor in Microbiology in the Perelman School of Medicine. He is a member of the Penn Bioengineering Graduate Group.
Speaker: Ilana Lauren Brito, Ph.D.
Assistant Professor, Mong Family Sesquicentennial Faculty Fellow in Biomedical Engineering
Meinig School of Biomedical Engineering
Cornell University
Date: Thursday, October 28, 2021
Time: 3:30-4:30 PM EDT
Zoom – check email for link or contact ksas@seas.upenn.edu
Room: Moore 216
Abstract: A major question regarding the human gut microbiota is: by what mechanisms do our most intimately associated organisms affect human health? In this talk, I will present several systems-level approaches that we have developed to address this fundamental question. My lab has pioneered methods that leverage protein-protein interactions to implicate bacterial proteins in human pathways linked to disease, revealing for the first time a network of interactions that affect diseases such as colorectal cancer, inflammatory bowel disease, type 2 diabetes and obesity that can be mined for novel therapeutics and therapeutic targets. I will present novel methods that that enable deeper insight into the transcriptome of organisms within our guts and their spatial localization. Finally, I will shift to the problem of the spread of antibiotic resistance, in which the gut microbiota are implicated. Pathogens become multi-drug resistance by acquiring resistance traits carried by the gut microbiota. Studying this process in microbiomes is inherently difficult using current methods. I will present several methods that enable tracking of genes within the microbiome and computational tools that predict the network of gene transfer between bacteria. Overall, these systems-level tools provide deep insight into the knobs we can turn to engineer outcomes within the microbiome that can improve human health.
Ilana Brito Bio: Ilana Brito is an Assistant Professor of Biomedical Engineering at Cornell University. Ilana received a BA from Harvard and a PhD from MIT. She started her postdoc as an Earth Institute Postdoctoral Fellow at Columbia University where she launched the Fiji Community Microbiome Project, a study aimed at tracking microbiota across people and their social networks, and continued this work at MIT and the Broad Institute working with Eric Alm. In her lab at Cornell, Ilana and her team are developing a suite of experimental systems biology tools to probe the functions of the human microbiome in a robust, high-throughput manner. Ilana has received numerous accolades for her work, including a Sloan Research Fellowship, Packard Fellowship, a Pew Biomedical Research Scholarship and an NIH New Innovator Award.
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.
The Department of Bioengineering at the University of Pennsylvania is excited to welcome César de la Fuente, Ph.D., as an Assistant Professor of Bioengineering. De la Fuente, who is also an Assistant Professor in the Department of Psychiatry and Microbiology in the Perelman School of Medicine and was recently named a Penn Presidential Professor, is the principal investigator of the de la Fuente Lab with current projects including the development of computer-made antibiotics, microbiome engineering technologies, and synthetic neuromicrobiology tools.
Dr. de la Fuente has wanted to learn the mysteries of the world around him from a young age, from the origins of life and human consciousness to how diseases can affect the body. His dream of understanding the building blocks of life began to take shape when he enrolled as a graduate student at the University of British Columbia to study microbiology, immunology, and protein engineering. After earning his Ph.D. in these subjects, de la Fuente went on to complete a post doctorate in synthetic biology and computer science at the Massachusetts Institute of Technology (MIT).
Recently, MIT recognized Dr. de la Fuente on its “35 Innovators Under 35” list, which honored de la Fuente as one of the world’s top 35 innovators and as a pioneer for his use of technology to improve antibiotics. Furthermore, GEN recently listed Dr. de la Fuente on its “Top 10 Under 40” list of young leaders in the life sciences, noting his development of transformative biotechnologies as a potential solution to antibiotic resistance. De la Fuente refers to this latest research as “Machine Biology,” a crossover of life and technology that “brings together elements of machines in order to computerize biological systems.”
His creativity in the merging of so many domains of science echoes throughout de la Fuente’s general approach to research and academia as well. While he emphasizes a thinking-from-the-ground-up approach, he also feels that “heterogeneous groups make better ideas,” and thus strives to maintain diversity in his lab — currently his entire lab is made up of international students and postdocs. In the future, de la Fuente hopes to extend his love of mentorship to the classroom in a course exploring the intersection of microbiology and synthetic biology, overlapping in a way similar to his research. We can’t wait for all of the innovation and creativity in engineering that de la Fuente will undoubtedly bring to our department.
