Project Outlines
This year Manchester-Graz team is trying to develop a whole new system for L-DOPA/dopamine treatment by regulating the pathway in an innovative way.
Fig 1 Administration of dopamine via gut bacteria
Low dopamine levels are linked to Parkinson’s disease, Alzheimer’s disease and several other health problems. The current treatment involves L-DOPA which crosses the blood-brain barrier, and is then enzymatically converted into dopamine. Studies show that Escherichia coli, Bacillus subtilis, Bacillus cereus, Bacillus mycoides, Proteus vulgaris, Serratia marcescens, and Staphylococcus aureus synthesize dopamine and that varying levels of dopamine in the gut can have neurological effects. Having bacteria in the gut producing dopamine would abolish the need for traditional medication, and only a single dose of culture in probiotics containing strains of self-regulating DOPA-producing bacteria will be needed. This is especially convenient for elderly people suffering from these diseases as there will be no such problem as an overdose or missing a medicine intake. This bacteria-based controlled drug delivery system incorporated could potentially improve the lifestyle of patients (Fig 1).
Fig 2 Novel dopamine expressing pathways
We plan to develop an innovative multidimensional cell density dependent auto-regulation system that could be used to control multistep enzyme pathways. L-DOPA is a good example as it is nowadays produced in bacterial cultures to cover the demand needed all over the world. The aim is to make the first steps in the development of a novel technology of drug delivery by developing self-regulating drug producing bacterial strains that, in the future, could be incorporated into patients’ intestinal and gut microflora to secrete medicines directly inside patients’ bodies in the response to any physiological changes, in particular low levels of dopamine.
Team Manchester is focusing on dopamine and L-DOPA biosynthesis. Two biochemical pathways will be worked on (Fig 2).
The team will identify the nature occurring enzymes for the biosynthetic pathways of L-DOPA and dopamine. Once biochemical pathways are proved to be credible, the genes of interest will be cloned into E.coli and correct synthesis will be further analyzed.
Graz-based team will use several regulation mechanisms for induction of protein expression such as carbon source dependent promoters and quorum sensing, along with other growth dependent systems. This is first demonstrated and visualized on the example of chromoprotein synthesis (Fig 3). The chromoproteins could then be exchanged with genes for the L-DOPA and dopamine production.
Fig 3 Chromoprotein synthesis dependent on different levels of cell density
Other possible applications for this project including in situ cell density measurement directly inside the bioreactor make it possible to know exactly when protein expression should be induced. Furthermore, human independent induction of protein expression by exchanging the chromoprotein gene with the corresponding gene of interest. From an economical point of view this system circumvents the problem of expensive inducers like IPTG. It also allows the consecutive expression of different proteins at variable points of time. One example would be the synthesis of a growth factor at early stage cell density and later switch to protein expression if cells are dense enough.
A main part of our project is also thinking about ethical problems, sociological aspects and human practices. This be discussed in detail not only on our webpage, but also with people on the streets. In these surveys, questions about public opinion concerning Synthetic Biology and genetic engineering will be asked. Survey data constructed by these discussions will be compared between Austria and UK