Identifying Genes Related to AnxietySpurthi Jayadeva, International Academy East, Troy, MI, 48083 & BioScience Project, Wakefield, MA 01880

Introduction• Occasional anxiety is normal and people experience it before they are in

stressful situations such as interviews, tests, public speaking, etc.

• Anxiety disorders, however, extend further than occasional anxiety. The stress

does not go away and it can get worse over time. There are types of anxiety

disorders such as generalized anxiety disorder, panic disorder, and social

anxiety disorder.

• People with generalized anxiety disorder worry for months and face many

symptoms that make it harder to continue everyday activities.

• People with panic disorder experience several panic attacks where they go

through sudden periods of intense fear.

• Social anxiety disorder causes people to have a fear of social or performance

situations where they have to be around other people.

(Source: https://www.nimh.nih.gov/health/topics/anxiety-disorders/index.shtml)

• Studies have shown that there is heightened amygdala activation in response to

stress (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055419/).. In this study

gene expression patterns in the amaygdala were evaluated to identify genes

related to anxiety. Methods

• The Allen Brain Atlas (http://www.brain-map.org/) was used to find the gene

expression data. The Differential Search was used in the Allen Human Brain

Atlas to find the expression of particular genes in a particular area of the brain,

or target structure (Amygdala), versus the other areas known as contrast

structures (gray matter). The search showed a heat map and data was collected

from four of the donors (H0351.2001, H0351.2002, H0351.1009, and

H0351.1012).

• Interactive Histogram (http://www.shodor.org/interactivate/activities/Histogram/)

was used to find the statistics for the fold-change values found in the Allen Brain

Atlas for the four donors.

• Venny 2.1 (http://bioinfogp.cnb.csic.es/tools/venny/) was used to find common

genes that are shared by all four of the donors.

• DAVID (https://david.ncifcrf.gov/) is a functional annotation tool that helped give

a biological meaning behind a large list of genes. This was used for cluster

analysis. Genes related to anxiety were found through keywords such as stress

and heart.

• The STRING database (https://string-db.org/) was used to find genes that are

associated with the genes that were found in the DAVID database.

Results1. Gene Expression Profiling

Donor A (H0351.2001)

Donor B (H0351.2002)

Donor C (H0351.1009)

Donor D (H0351.1012)

The heat maps show the

gene expression data for

the four chosen donors.

The genes are sorted

from the highest to the

lowest fold-change. The

bar at the top represents

the donor and the bar

under it represents

different parts of the

amygdala. Each row of

the heat map represents

a probe. Each column

represents a tissue or

anatomical brain

structure. Red represents

relatively high expression

and green represents

relatively low expression

in the heat map. The top

two hundred genes were

then downloaded and

analyzed. The gene

symbol, p-value, and

fold-change were used

for the following steps in

the project.

2. Common Genes

After creating a Venn Diagram using the top twenty highest

expressing genes for each donor, the results showed that

there are thirty three common genes that are shared by all of

the donors. This means that 16.8% of the data was common

among all of the donors.

Common Genes

DCSTAMP

MYB

PDYN

KCTD4

UTS2D

NPY

PTGER3

MOXD1

GDA

ZNF831

FOXG1

LOC392145

GABRQ

TRHR

HTR2C

CARTPT

CD36

ZCCHC12

CXXC11

DIRAS3

MYH6

ARHGAP6

BCL11B

C6orf118

TFAP2D

ANO3

NR2F2

GLRA3

PRSS35

PCDH11Y

GABRA2

TNFAIP8L3

KCNG3

3. Top 20 Highest Expressing Genes

Donor A (H0351.2001)

Donor B (H0351.2002)

Donor C (H0351.1009)

The charts show graphs for the top twenty highest expressing genes for each donor.

The blue graphs show a relationship between the fold-change and the gene symbol

while the red graphs show a relationship between the p-value and the gene symbol.

4. Data Distribution

In the histograms, the x-axis shows the fold-change

values and the y-axis shows the frequency of the

fold-change values. The histograms for all four

donors are skewed right because most of the genes

have lower fold-change values. The average fold-

change ranges between seven and twelve.

5. Genes of Interest

The common genes between all of the donors were put into the DAVID

database. No genes of interest for anxiety in humans were found.

Genes from the common gene list related to stress were found in a

study with mice (www.geneweaver.org). Key word search for terms

related to anxiety such as “stress” and “addiction” led to the genes of

interest.

HTR2C MYH6

CARTPT

CD36

PDYN

The genes of interest were put into the STRING database to identify interacting

partners . Networks were created based on experimentally validated interactions.

The related genes in the network from the STRING database were plugged back

into the DAVID database to see if any of the genes were directly elated to anxiety.

Each gene of interest’s list was plugged in separately. Although non of the lists

directly related to anxiety, MYH6’s list showed many genes of interest for the

keyword “stress.” This was then narrowed down to one gene that related the most to

stress. This was protein phosphatase 3 catalytic subunit alpha or PPP3CA. It has

“cardiac muscle hypertrophy in response to stress”, “multicellular organismal

response to stress”, and “positive regulation of cardiac muscle hypertrophy in

response to stress.” It also has “cellular response to drug” which is helpful because

drugs increase the risk of anxiety. This gene of interest related the most to anxiety

and stress.

Conclusion

• Anxiety is a disorder that is becoming more and more common

every single day. There is still a lot of research that needs to be

done because there are many factors that contribute to it.

• The amygdala is a region of the brain that is affected by anxiety

and stress. There are other regions that may be researched to find

more information about it.

• Six genes of interest were identified and then expanded using the

DAVID and STRING databases. Since there are many other

factors that related and contribute to stress and anxiety, there are

most likely many more genes of interest.

• PPP3CA was found to be related to stress and it should be further

researched to see if it has a role in everyday stress or if it has a

larger role in contributing to anxiety. This is a good candidate for

another study.

• Other genes that were identified throughout the project could also

be researched further in order to determine if they contribute to

stress or anxiety.