The influence of bipolar drugs on the phospholipid biosynthetic pathway in Saccharomyces cerevisiae

This study investigates a specific yeast, Saccharomyces cerevisiae, to model the effect of Valproic acid and Lithium Chloride in humans. These drugs are known to treat Bipolar disorder and affect genes that synthesize inositol in the phospholipid biosynthetic pathway. By testing different strands of cells

with the presence and absence of inositol, we were able to collect absorbance values (OD) using a spectrophotometer. With time, we will use the qPCR treatment to quantify the gene expression of INM1 gene, which is responsible for the inositol production.

ConclusionBased on our results and data calculations, we will continue

our research in hopes of better understanding the gene expression of INM1, by using First Strand Synthesis and qPCR. These tests will quantify our results as it amplifies

our DNA copies. The lipid biosynthetic pathway is a growing area of molecular biology research, and there is a lot to gain when applying these experimental analyses to

various social applications.

MethodsTo conduct this experiment we took previously grown cells

and used a spectrophotometer to measure the Optical Density. From this collected data, we were able to construct various growth curves representing the Optical Density with respect to time. Two main yeast strains that were used in this analysis were, “#3” and “#27,” respectively modeling wild type and ino2Δ. Wild type, strand #3, was used to represent normal cells containing all genes in the presence of inositol. Strand #27 deleted the ino2 protein, which deactivated the

synthesis of inositol, resulting in inositol absent media. SC+ denotes the addition of inositol in the media, while SC- denotes the absence of inositol in media. Both analyses were performed with either of the two bipolar drugs.

Introduction“Bipolar disorder affects approximately 5.7 million adult

Americans, or about 2.6% of the U.S. population age 18 and older every year”(DBSA). This disorder can be treated with drugs containing Valproic acid, Lithium Chloride and genes

that synthesize inositol. Specifically, these drugs affect genes that are responsible for de novo synthesis of inositol in the

phospholipid biosynthetic pathway. The study will be conducted using Saccharomyces cerevisiae as a model

organism. This yeast cell has genes in this pathway that are evolutionarily conserved, making it comparable to the

human genome. We will be investigating INM1, a model gene in this pathway because previous research has shown,

INM1 expression is affected by inositol, a carbon source and growth stage, as well as lithium and Valproic acid.

References(2013). Expression atlas. The European Bioinformatics Institute, Retrieved from

http://www.ebi.ac.uk/gxa/gene/YHR046C

Depression and bipolar support alliance. (n.d.). Retrieved from http://www.dbsalliance.org/site/PageServer/Calendar/PageServer?

pagename=education_statistics_bipolar_disorder

Marlene Murray and Miriam L. Greenberg.(2000) Expression of yeast INM1 encoding inositol monophosphatase is regulated by inositol, carbon source and

growth stage and is decreased by lithium and valproate. Department of Biological Sciences, Wayne State University

Data & ResultsWe found that the greatest Optical Density was found in that of #3,

Lithium Chloride, and SC+. The lowest Optical density was found in that of #27 Lithium Chloride and Valproic acid SC-. We also found out that Optical Density will plateau around 30 hours, because cells begin

to die, regardless of inositol production.

Brendon Ursomanno and Christina Moawad

AcknowledgmentsWe would like to thank Dr. Shen and his entire lab,

including Paulina, Michelle, Goldie, and Gracie. Also, Dr. Liu for being there for us with guidance and moral support

along the way.

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#3 & #27 Growth Curve

#27 SC+ val

#27 SC+ LiCl

#27 SC- val

#27 SC- LiCl

#3 SC+ val

#3SC+ LiCl

#3 SC- val

#3 SC- LiCl

Time (Hours)

O.D

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DiscussionBased on our optical density readings, we were able to

clearly see the effect that the two drugs, Lithium Chloride and Valporic acid had on the specific yeast cell. We see that

Lithium Chloride has a greater effect than Valproic acid; although both clearly do increase O.D. concentrations.

There is a direct relationship between increased time and O.D. concentrations. But, eventually they will plateau because all inositol in the media is used, or no more is

being produced de novo and the cells begin to die. For the mutant cell, with SC- there is no inositol in the media nor in the cell, making the O.D. concentrations approximately

zero for the entire experiment. Our study confirms the effect that LiCl and Val have on the cells gene expression,

and further experiments can quantify these effects.