Team:Paris Bettencourt/Project/TB-ception
From 2013.igem.org
Line 12: | Line 12: | ||
Bacterial vectors offer a biological route to gene and protein delivery to cells such as macrophages. We want to investigate the potential use of Escherichia coli as a bacterial vector to kill Mycobacerium tuberculosis. We will introduce an expression system containing a gene for a cutinase-like serine esterase that triggers rapid lysis of the mycobacterial cell wall and a gene encoding a protein which forms large pores in the phagosomal membrane where mycobacteria are located, thus releasing the target protein into the cytosol. | Bacterial vectors offer a biological route to gene and protein delivery to cells such as macrophages. We want to investigate the potential use of Escherichia coli as a bacterial vector to kill Mycobacerium tuberculosis. We will introduce an expression system containing a gene for a cutinase-like serine esterase that triggers rapid lysis of the mycobacterial cell wall and a gene encoding a protein which forms large pores in the phagosomal membrane where mycobacteria are located, thus releasing the target protein into the cytosol. | ||
</b> | </b> | ||
+ | </p> | ||
+ | <p> | ||
+ | Tuberculosis is a disease on the rise in recent years. Despite numerous technological advances, this disease is difficult to treat and diagnose. We are interested in for this project only to the difficulties inherent to the treatment. <br> | ||
+ | When we think about bacteria and health we always think about problems such as antibiotic resistances. Imagine that this time the bacteria will not be against you but with you.<br> | ||
- | + | </p> | |
- | + | <h3>Problematic </h3> | |
+ | <p> | ||
+ | Mycobacterium tuberculosis subverts the immune system. It stays latent in the macrophages and evades destruction by preventing the phagosome maturation. We need to find a new way to reach it.<br> | ||
- | + | </p> | |
- | + | <h3>Aim</h3> | |
- | + | <p> | |
- | + | Use bactofection to target the immune system (especially the macrophages) and deliver a protein that will kill the Mycobacteria. <br> | |
- | Use bactofection to target the immune system (especially the macrophages) and deliver a protein that will kill the Mycobacteria. | + | |
Background: | Background: |
Revision as of 12:22, 1 October 2013
<body>
![](https://static.igem.org/mediawiki/2013/6/6c/PB_infiltrate.gif)
Bacterial vectors offer a biological route to gene and protein delivery to cells such as macrophages. We want to investigate the potential use of Escherichia coli as a bacterial vector to kill Mycobacerium tuberculosis. We will introduce an expression system containing a gene for a cutinase-like serine esterase that triggers rapid lysis of the mycobacterial cell wall and a gene encoding a protein which forms large pores in the phagosomal membrane where mycobacteria are located, thus releasing the target protein into the cytosol.
Tuberculosis is a disease on the rise in recent years. Despite numerous technological advances, this disease is difficult to treat and diagnose. We are interested in for this project only to the difficulties inherent to the treatment.
When we think about bacteria and health we always think about problems such as antibiotic resistances. Imagine that this time the bacteria will not be against you but with you.
Problematic
Mycobacterium tuberculosis subverts the immune system. It stays latent in the macrophages and evades destruction by preventing the phagosome maturation. We need to find a new way to reach it.
Aim
Use bactofection to target the immune system (especially the macrophages) and deliver a protein that will kill the Mycobacteria.
Background:
Why in the 21st century is it so difficult to treat tuberculosis?
This is due to several parameters linked to the nature of the pathogen, Mycobacterium tuberculosis:
- This bacterium has the power to replicate or remain dormant for years inside the macrophages. It happens by many complex mechanisms including prevention of the phagosomal maturation. This phenomenon involves coronin-12.
- The cell wall of M.tuberculosis is very complex and it's difficult for drugs to get inside
- The growth of the bacteria is very slow and majority of drugs can reach only bacteria which are dividing.
Approach:
We wanted to overcome these issues using 2 approaches:
In the first one we want to introduce an expression system containing a gene for a cutinase-like serine esterase that triggers rapid lysis of the mycobacterial cell wall and a gene encoding a protein which forms large pores in the phagosomal membrane where mycobacteria are located, thus releasing the target protein into the cytosol. In the second one we want to develop a bacteria-based iRNA delivery system for silencing the coronin-1 gene of the macrophages. Coronin-1 is a protein which surrounds the mycobacterial phagosome allowing mycobacteria to survive within them. Silencing of this gene will result in the enhancement of the lysosome/phagosome fusion.
Only the first approach was developped during iGEM.
Model:
We used Mycobacterium smegmatis as a model. This model was chosen because it is non-pathogenic and it grows quickly (comparing to Mycobacterium tuberculosis)
Main results:
Killing assay outside the macrophages
We performed a killing assay using different ratios of bacteria:
1 E.coli for 1 M.smegmatis
1 E.coli for 10 M.smegmatis
1 E.coli for 100 M.smegmatis
2 ratios were successful regarding the killing of M.smegmatis: 1 to 10 and 1 to 1.
In the 1 to 100 ratio we observed a recovery of M.smegmatis.
We decided that we will use the 1/1 ratio for the rest of our experiments.
Bibliography:
1. Yang Y, Bhatti A, Ke D, Gonzalez-Juarrero M, Lenaerts A, Kremer L, Guerardel Y, Zhang P, Ojha AK (2012) : Exposure to a cutinase-like serine esterase triggers rapid lysis of multiple mycobacterial species. J Biol Chem. 2013 Jan 4;288(1):382-92.
2. Rajesh Jayachandran, 4, Varadharajan Sundaramurthy, Benoit Combaluzier , Philipp Mueller, Hannelie Korf, Kris Huygen, Toru Miyazaki, Imke Albrecht, Jan Massner, Jean Pieters (2007) : Survival of Mycobacteria in Macrophages Is Mediated by Coronin 1-Dependent Activation of Calcineurin. Cell, Volume 130, Issue 1, 13 July 2007, Pages 12-14
![](https://static.igem.org/mediawiki/2013/0/0f/TB_Ception_Figure.png)