Team:Evry/Project

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<h1>Abstract</h1>
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<h1>Overview</h1>
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Our project focuses on developing a novel treatment for <a href="https://2013.igem.org/Team:Evry/Project_diseases">hematological disorders</a> caused by an <a href="https://2013.igem.org/Team:Evry/Project_metabolism">iron overload</a>, such as hemochromatosis and thalassemia. These autosomal recessive disorders have symptoms including cirrhosis, arthritis, and heart failure, which result from overabsorption of iron from the duodenum. Although these are among the most common heritable diseases, treatment options are limited. Even today patients are mostly treated by frequent bloodletting, which <a href="https://2013.igem.org/Team:Evry/HumanPractice/Patients_perceptions">many people cannot support</a>. The aim of our project is to combat these diseases at the source by developing a therapy that prevents the intestinal absorption of iron.
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Our Iron Coli Project deals with <a href="https://2013.igem.org/Team:Evry/Project_diseases">hemochromatosis</a>. Hemochromatosis is an autosomal recessive disorder which is the most frequent genetic disease in Europe as it affects over two millions people. It is caused by a mutation on the HFE gene, which leads to an <a href="https://2013.igem.org/Team:Evry/Project_metabolism">overabsorption of iron</a> in the upper region of the intestine. This iron overload is stored in many organs and tissues, which eventually causes chronic insuficiences as heart, liver and kidney failures.
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We engineer the <i>Escherichia coli</i> <a href="https://2013.igem.org/Team:Evry/Project_FUR">Ferric Uptake Regulation</a> (FUR) system using a <a href="https://2013.igem.org/Team:Evry/Inverter">genetic inverter</a> so that they produce siderophores (<a href="https://2013.igem.org/Team:Evry/Chelator">iron chelators</a>) in response of high concentrations of iron. These engineered bacteria are delivered to the patient's intestine by encapsulating them in an ingestible polymer (<a href="https://2013.igem.org/Team:Evry/Pill_design">capsule</a>)  that specifically degrades in the duodenum. Once released into the intestine, the bacteria respond to ambient iron by secreting elevated levels of siderophores, thereby chelating the iron to prevent its absorption by the patient.
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The only available treatment for patients suffering from hemochromatosic nowadays is blood-lettings. <a href="https://2013.igem.org/Team:Evry/Seminar">Discussing with patients</a> we discover that this treatment is time-consumming and is often barely tolerated. To find a solution, we worked on the creation of a bacterial treatment to prevent iron overload in hemochromatosis.</p>
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We focused on a natural iron <a href="https://2013.igem.org/Team:Evry/Project_FUR">chelating molecule</a> called enterobactins that is produced in iron starvation case by <i>E. coli</i>. For our project, we wanted to invert this natural behaviour, so <i>E. coli</i> would produce these enterobactins in high iron concentration. To deliver our bacteria right in the duodenum where it would prevent the iron absorption, we also worked on the design of a gastro resistant <a href="https://2013.igem.org/Team:Evry/Pill_design">capsule</a>.
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The <b><span style="color:#bb8900">Iron</span><span style="color:#7B0000"> Coli</span> Project</b> deals with iron, and more precisely about the most frequent genetic disease related to that ion, <b>hemochromatosis</b>. In our human body, iron is essentially found under a hemic structure. For example, iron is bound to hemoglobin inside red cells to transport oxygen. Also, iron bound to cytochrome carry the function of detoxification in the liver but also energy production by the mitochondria.<br>
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We first wanted to know if our bacterial treatment would be accepted by the patients. Then, we conducted a <a href="https://2013.igem.org/Team:Evry/HumanPractice/Patients_perceptions">survey</a> to ask for their opinion. It appears that a majority of hemochromatosic patients would actually agree on taking our treatment. <br/>
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So iron is essential to our human body for many metabolic pathways. In fact, it is finely regulated in our human body and unfortunately, the unbalance of this smooth regulation leads has dramatic consequences. Our human body has a total pool of 4000 mg of iron. Every day, we absorb 1 mg by the upper intestine (duodenum and jejunum) and excrete 1 mg by tissue renewel (intestin, skin, hair, bleeding, etc...). However, a hemochromatosic patient absords on average 4 times more iron. On a long term, this patient accumulates the iron which is very toxic in its free form. The only mechanism we have to decrease the blood level of iron is to store it in our tissues. Heart, liver, kidneys, muscles, all these organs start to store the iron, which enhances its toxicity. This
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We also created a <a href="https://2013.igem.org/Team:Evry/Safety">fault tree</a> to identify the consequences involved if <i>E. coli</i> will stay permantly or temporarily into the intestine. This study oriented our modelling team to a <a href="https://2013.igem.org/Team:Evry/flush_model">flush strategy</a>, meaning that <i>E. coli</i> only stays temporarily in the intestine. Their model predicted that our engineered <i>E. coli</i> (<b><span style="color:#bb8900">Iron</span><span style="color:#7B0000"> Coli</span></b>) could divide by two the amount of iron absorbed by a hemochromatosic patient.<br/>
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Knowing that our treatment would be accepted and beneficial to patients, we then focused on the biology of our project. We obtained two biobricks : an <a href="https://2013.igem.org/Team:Evry/Sensor">iron sensing device</a> and an <a href="https://2013.igem.org/Team:Evry/Inverter">inverter signal system</a>.
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We wonder how much time it would take for our <b><span style="color:#bb8900">Iron</span><span style="color:#7B0000"> Coli</span></b> to produce enterobactin and if overproducing them would unbalance <i>E. coli</i> metabolism. Results obtained from the <a href="https://2013.igem.org/Team:Evry/Metabolism_model">Flux Balance Analysis</a> and a <a href="https://2013.igem.org/Team:Evry/Modelmeta3">differencial equation model</a> leads our biologists to optimize their construction and design a <a href="https://2013.igem.org/Team:Evry/Pill_design">delivery capsule</a>.
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Through our project, we managed to made an integrated <a href="https://2013.igem.org/Team:Evry/HumanPractice">human practice</a> study as well as creating useful <a href="https://2013.igem.org/Team:Evry/Modeling">models</a> that both equally contributed to the realisation of our final project.
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Latest revision as of 03:43, 29 October 2013

Iron coli project

Overview

Our Iron Coli Project deals with hemochromatosis. Hemochromatosis is an autosomal recessive disorder which is the most frequent genetic disease in Europe as it affects over two millions people. It is caused by a mutation on the HFE gene, which leads to an overabsorption of iron in the upper region of the intestine. This iron overload is stored in many organs and tissues, which eventually causes chronic insuficiences as heart, liver and kidney failures.

The only available treatment for patients suffering from hemochromatosic nowadays is blood-lettings. Discussing with patients we discover that this treatment is time-consumming and is often barely tolerated. To find a solution, we worked on the creation of a bacterial treatment to prevent iron overload in hemochromatosis.

We focused on a natural iron chelating molecule called enterobactins that is produced in iron starvation case by E. coli. For our project, we wanted to invert this natural behaviour, so E. coli would produce these enterobactins in high iron concentration. To deliver our bacteria right in the duodenum where it would prevent the iron absorption, we also worked on the design of a gastro resistant capsule.

We first wanted to know if our bacterial treatment would be accepted by the patients. Then, we conducted a survey to ask for their opinion. It appears that a majority of hemochromatosic patients would actually agree on taking our treatment.
We also created a fault tree to identify the consequences involved if E. coli will stay permantly or temporarily into the intestine. This study oriented our modelling team to a flush strategy, meaning that E. coli only stays temporarily in the intestine. Their model predicted that our engineered E. coli (Iron Coli) could divide by two the amount of iron absorbed by a hemochromatosic patient.
Knowing that our treatment would be accepted and beneficial to patients, we then focused on the biology of our project. We obtained two biobricks : an iron sensing device and an inverter signal system.

We wonder how much time it would take for our Iron Coli to produce enterobactin and if overproducing them would unbalance E. coli metabolism. Results obtained from the Flux Balance Analysis and a differencial equation model leads our biologists to optimize their construction and design a delivery capsule.

Through our project, we managed to made an integrated human practice study as well as creating useful models that both equally contributed to the realisation of our final project.