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Quantification and rescue of alpha-synuclein-induced cell growth impair in yeast by high-throughput screening

Song, Lin (2012) MOBT19 20112
Degree Projects in Molecular Biology
Abstract
ABSTRACT

Parkinson’s disease (PD) is a common neurodegenerative disorder disease that mostly
affects individuals over the age of 50 all over the world. It is caused by the loss of
dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc).
Overexpression or mutation of α-synuclein have been identified as the direct cause of
cell loss and dominant inherited PD, although the mechanism is not clear yet.
Multiple biological models were used in the research to elucidate the mechanisms and
to develop new therapies for this disease. In the present study, we screened an
established yeast model induced by galactose and marked with fluorescence for the
overexpression-induced toxicity of α-synuclein protein, which can cause... (More)
ABSTRACT

Parkinson’s disease (PD) is a common neurodegenerative disorder disease that mostly
affects individuals over the age of 50 all over the world. It is caused by the loss of
dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc).
Overexpression or mutation of α-synuclein have been identified as the direct cause of
cell loss and dominant inherited PD, although the mechanism is not clear yet.
Multiple biological models were used in the research to elucidate the mechanisms and
to develop new therapies for this disease. In the present study, we screened an
established yeast model induced by galactose and marked with fluorescence for the
overexpression-induced toxicity of α-synuclein protein, which can cause yeast cell
death. Blueberries were previously shown to be neuroprotective in primary midbrain
cultures. To determine effective protective compounds to rescue the cell loss caused
by the α-synuclein protein, the blueberry compound library was screened by the
high-throughput screening. The hits in the yeast screen will be applied to protect the
SHSY5Y cells treated with rotenone

Popular science summary:

Compounds Selection for Parkinson’s Disease Rescue

It has been proved that the α-synuclein protein plays an important role in Parkinson’s disease. In this project, we have the α-synuclein protein expressed in yeast cells and the growth condition monitored to made sure that the growth were impaired by the expression of α-synuclein protein. Finally, the yeast cells were treated with compounds to evaluate the cell rescue effection.

Four different yeast strains - one control strain and three experimental strains with different α-synuclein overexpression genes – were adopted in this project. The α–synuclein genes were fused to a fluorescent marker, which can be used to confirm if the gene is expressed or not. The expression of the fused gene was under control of the GAL1 promoter, which can be induced by galactose and inhibited by glucose. Thus the expression of α–synuclein gene can be manipulated by adding galactose to the medium.

The yeast strains were cultured with the presence of galactose, glucose raffinose respectively. The OD (Optical density) of the yeast strains with different sugars was measured for 48 hours to monitor the growth condition, and we found that the strains with α–synuclein gene cannot grow normally in galactose while the control strain can. And all the four strains could grow normally in glucose and raffinose respectively.

Compounds Selection
Previous researches showed that greater intake of blueberries could reduce the risk of Parkinson’s disease, but what component in blueberries works is not clear. Our collaborators obtained the extrications from blueberries try to find out their effect on Parkinson’s disease treatment. Yeast cells were treated with these compounds and cultured in the medium with galacose, followed by the measurement of the OD for 48 hours.

From the results, we find that the growth of control strain was not effected by galactose while the growth of three strains with expression of α–synuclein was impared. However, when treated with different concentrations of anthocyanidins (Com3) and proanthocyanidins (Com 7), the effect of α–synuclein can be eliminated. And the anthocyanidins and proanthocyanidins will be tested in human neuron cells in the future.


Advisor: Vincent Jo Davisson
Master´s Degree Project 60 credits in Molecular Genetics* 2011-2012
Department of Biology, Lund University

*Subject of degree project: see Description of the course (Less)
Please use this url to cite or link to this publication:
author
Song, Lin
supervisor
organization
course
MOBT19 20112
year
type
H2 - Master's Degree (Two Years)
subject
keywords
α-Synuclein toxicity, Parkinson’s disease, yeast, high-throughput screen, cell death rescue
language
English
id
3615278
date added to LUP
2013-03-20 16:37:57
date last changed
2013-03-26 13:38:21
@misc{3615278,
  abstract     = {ABSTRACT

Parkinson’s disease (PD) is a common neurodegenerative disorder disease that mostly
affects individuals over the age of 50 all over the world. It is caused by the loss of
dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc).
Overexpression or mutation of α-synuclein have been identified as the direct cause of
cell loss and dominant inherited PD, although the mechanism is not clear yet.
Multiple biological models were used in the research to elucidate the mechanisms and
to develop new therapies for this disease. In the present study, we screened an
established yeast model induced by galactose and marked with fluorescence for the
overexpression-induced toxicity of α-synuclein protein, which can cause yeast cell
death. Blueberries were previously shown to be neuroprotective in primary midbrain
cultures. To determine effective protective compounds to rescue the cell loss caused
by the α-synuclein protein, the blueberry compound library was screened by the
high-throughput screening. The hits in the yeast screen will be applied to protect the
SHSY5Y cells treated with rotenone

Popular science summary:

Compounds Selection for Parkinson’s Disease Rescue

 It has been proved that the α-synuclein protein plays an important role in Parkinson’s disease. In this project, we have the α-synuclein protein expressed in yeast cells and the growth condition monitored to made sure that the growth were impaired by the expression of α-synuclein protein. Finally, the yeast cells were treated with compounds to evaluate the cell rescue effection. 

Four different yeast strains - one control strain and three experimental strains with different α-synuclein overexpression genes – were adopted in this project. The α–synuclein genes were fused to a fluorescent marker, which can be used to confirm if the gene is expressed or not. The expression of the fused gene was under control of the GAL1 promoter, which can be induced by galactose and inhibited by glucose. Thus the expression of α–synuclein gene can be manipulated by adding galactose to the medium.

The yeast strains were cultured with the presence of galactose, glucose raffinose respectively. The OD (Optical density) of the yeast strains with different sugars was measured for 48 hours to monitor the growth condition, and we found that the strains with α–synuclein gene cannot grow normally in galactose while the control strain can. And all the four strains could grow normally in glucose and raffinose respectively.

Compounds Selection
Previous researches showed that greater intake of blueberries could reduce the risk of Parkinson’s disease, but what component in blueberries works is not clear. Our collaborators obtained the extrications from blueberries try to find out their effect on Parkinson’s disease treatment. Yeast cells were treated with these compounds and cultured in the medium with galacose, followed by the measurement of the OD for 48 hours.

From the results, we find that the growth of control strain was not effected by galactose while the growth of three strains with expression of α–synuclein was impared. However, when treated with different concentrations of anthocyanidins (Com3) and proanthocyanidins (Com 7), the effect of α–synuclein can be eliminated. And the anthocyanidins and proanthocyanidins will be tested in human neuron cells in the future.


Advisor: Vincent Jo Davisson
Master´s Degree Project 60 credits in Molecular Genetics* 2011-2012
Department of Biology, Lund University

*Subject of degree project: see Description of the course},
  author       = {Song, Lin},
  keyword      = {α-Synuclein toxicity,Parkinson’s disease,yeast,high-throughput screen,cell death rescue},
  language     = {eng},
  note         = {Student Paper},
  title        = {Quantification and rescue of alpha-synuclein-induced cell growth impair in yeast by high-throughput screening},
  year         = {2012},
}