Inflammatory bowel disease (IBD)
4.9 million people worldwide suffer from inflammatory bowel disease[1]. It is a lifelong disease with periods of flares and periods of remission. The disease causes patients to have chronic inflammation in the gut, leading to symptoms like diarrhea, abdominal pain, bloody stools and fatigue for days[2]. The current treatments for the disease are systemic, meaning they affect the whole body, but this causes many unnecessary side effects [2]. This is why we want to design better treatment options for patients suffering from IBD.
Our solution
Treating IBD is not yet possible without many side effects and a lot of money. To solve these problems, we genetically engineer E.coli to turn them into a probiotic. This resulted in the development of cELPro. As you can see in Figure 2, the inserted bacteria contain with two plasmids. One of which produces Elastin-Like Polypeptides (ELPs) that form an intracellular hydrogel. The other one produces the therapeutic Interleukin 10 (IL-10).
ELPs are synthetic biopolymers that have an affinity for each other based on hydrophobic interactions[3]. To increase the affinity even further, they were equipped with complementary Leucine zipper cross-linkers attached at their ends. The hydrogel forms in a temperature-dependent manner based on these interactions[4]. The goal of the hydrogel is to make sure that the bacteria stop dividing, which makes them safer to ingest. They are not able to grow out of control anymore once the gel is formed, but they can still produce the therapeutic IL-10. This makes the release of IL-10 controlled and provides a great alternative to current treatment options.
Interleukin 10 (IL-10) is an anti-inflammatory cytokine made by most cells of the immune system. It acts via limiting immune responses during infection, allergic reactions, and autoimmunity. IL-10 plays a central role in the prevention of immune-mediated damage to the host. However, because of its immunosuppressive effects, too much IL-10 can cause chronic infections[5]. This is part of the reason that systemic use of IL-10 has not been successful yet in the treatment of IBD. By administering IL-10 locally with bacteria in cELPro, these problems are tackled.
Advantages
By forming the hydrogel, the bacteria become unable to divide. An advantage of this approach is that all the machinery to make the hydrogel is present in the bacteria, which makes the approach more scalable and affordable. The system requires the addition of the plasmid to the bacteria that encodes for the proteins that form the hydrogel and another one that encodes for the therapeutic protein before they are grown in large quantities. When the hydrogel needs to be formed, all that is needed is to increase the temperature to above the transition temperature of 23 degrees Celcius. Furthermore, the production of bacteria is generally easier than the production of complicated antibodies, which makes this solution more scalable compared to current treatment options as well. Lastly, our approach can be seen as a modular platform as it has potential expansion to address various intestinal diseases in a non-invasive manner.
If you want to know more about our project, take a look at our Wiki:
https://2023.igem.wiki/tu-eindhoven/index.html
