1. wound healing involves a complex series of biochemical events that progress in distinct stages:...
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1.
Wound healing involves a complex series of biochemical events that progress in
distinct stages: inflammation, proliferation and remodeling. While tissue repair
takes place during the proliferative and remodeling stages, chronic wounds resulting
from inflammatory bowel disease (IBD) are locked in an inflammatory state and
resist the body’s natural ability to repair tissue.
According to the Centers for Disease Control, IBD is 1 of the 5 most prevalent
gastrointestinal diseases in the United States, accounting for 100,000
hospitalizations and $1.7 billion dollars in health care costs each year. With only a
few durable treatments, these disorders remain without a cure.
Introduction
Approach
Towards Intelligent ProbioticsChris Brasseaux, David Golynskiy, Tyler Guinn, Sameer Sant,
Mitu Bhattatiry, Nimi Bhattatiry, Alfredo Flores
Control Unit Immunobot
KillbotImmunobot
Sensor Interface Taxis
Applications
Characterization
Design
Scheme
Probiotics are living microorganisms that can confer a benefit to their host. Live
cultures present in regular yogurt products are examples of everyday probiotics.
We imagined an intelligent probiotic that can process inputs that indicate tissue
damage and produce a programmed output. While the human body itself consists
of 100 trillion cells, the bowel hosts 10 times as many microorganisms that exist as
part of a mutually beneficial symbiotic relationship. This incredible diversity of
symbionts represents a potentially powerful engineering platform for intelligent
probiotics that address IBD.
In 2009, Stanford developed a two-component probiotic that regulates the activity
of Th17 and Treg lymphocytes in order to control tissue inflammation and allow
normal wound healing to proceed into the proliferative and remodeling phases.
We aimed to build on their work in two ways: i) by engineering a wound sensing
ability into E. coli, and ii) by developing a means for the user to control probiotic
activity.
This work has applications in health and medicine. Our engineered two-
component system can be integrated with devices that recruit wound repairing
agents at the site of tissue damage. More broadly, intelligent probiotics offer
great promise as therapeutic tools for health-related issues such as devices that
can process inputs such as nutrient imbalances and affect balance-restoring
outputs.
Construct 1
Intracellular levels of CheY-P and CheY control flagellar motors
(FliM). High [CheY-P] results in “tumbles” (no net movement)
whereas high [CheY] results in “runs” (straight-line movement).
FGFR-ToxR chimeric receptor activates CTX-controlled
chemotaxis, thus connecting FGF wound signaling to
movement.
Fibroblast growth factor (FGF), a wound signal, induces the
dimerization of FGF receptor (FGFR), triggering FGF signal
transduction.
Construct 3Construct 2
Time
Delivery/Glucose
Population 1 (Immunobot) Population 1 (Immunobot) + more Population 2 (Killbot)
Population 1 (Immunobot) + Population 2 (Killbot)
Immunobot Experiments
Killbot Experiments
Modeling and SimulationsActivation of
Receptor
Dimerization of Receptor
Transcription and translation of CheZ
Dephosphorylation of CheY
Prediction of tumbling activity
Acknowledgements
Human Practices
Accomplishments
Recent global health concerns have focused greater attention on development assistance measures
oriented towards addressing chronic health diseases. Advancements in synthetic biology, such as
intelligent probiotics, may serve as important tools to enhance current global health initiatives. They
may be engineered to recognize issue-specific signals that elicit issue-specific responses, thus enhancing
approaches taken towards achieving the first UN Millennium Development Goal: curbing global
malnutrition and hunger. Intelligent probiotics provide potential applications in the grand strategic
approach to global health, or the practice of “achieving large ends with limited means.” In context of
health-oriented grand strategy outlined by Curry et al., applications of intelligent probiotics can employ
the following principles:
I. Start with the goal in mind
UTD iGEM’s end goal was the development of an intelligent probiotic using an E.coli chassis, a bowel
symbiont. As a proof of purpose, our application involved mitigating inflammatory bowel disease.
II. Tactics matter
It may prove less resource intensive to improve the efficiency of existing materials (probiotics) at
addressing the issue of malnutrition rather than simply channeling more resources into combating the
problem.
III. Take an ecological approach
On a microscale, our approach involved two goals: i) engineering wound sensing ability (immunobot)
and ii) enabling population control (killbot). Killbots were developed as a biosafety tool to manage
unintended consequences associated with using immunobots. On a macroscale, we attempt to illustrate
the utility of intelligent probiotics to global health organizations currently grappling with the
malnutrition issue. Our system may enhance the effectiveness of current initiatives by making them
more cost-effective.
Hence, we believe that grand strategic thinking in synthetic biology will better help connect future
developments in biotechnology with their intended beneficiaries.
We would like to express our sincerest thanks to the following people for their generous support during our iGEM experience:• To our mentors whose guidance which was invaluable to the success of our project.• To Kristina Ehrhardt, Neha Kashyap, and Lagnajeet Pradhan who provided additional
support carrying out experiments and also encoding the wiki and Android apps.• To UT Dallas for providing a facility to carry out our lab experiments.• To Dr. Ruth Silversmith (UNC School of Medicine) and Ms. Britta Herzog (University
of Göttigen) for providing us some important constructs. • To the Institute of Biological Engineering for hosting us at the Americas Jamboree.• To iGEM for giving our team this incredible opportunity.
• Entered information detailing at least one new standard BioBrick (BBa_K569001) in the Registry of Standard Biological Parts.
• Demonstrated that at least one new BioBrick (BBa_K569001) of our own design and construction works as expected. We also characterized its operation and entered this information and other documentation on the appropriate Registry page.
• Improved the characterization of BBa_K131010, an existing BioBrick, and entered our experience in the appropriate Registry page.
• Outlined and detailed a new grand strategic approach to Human Practices in connecting intelligent probiotics with ongoing initiatives in the global health arena to enhance their impact.