FANCJ

1. I M PA C T O F FA N C J
O N H E A R T
H E A LT H
K A I T L I N L O W R A N , I N G R I D
P E T E R S E N , L A U R A C A M P B E L L ,
C O L I N G . W U

2. W H AT D O W E S T U D Y ?
• DNA repair mechanisms
• How do enzymes recognize damaged
DNA sites in our cells?
• How do mutations of these enzymes
affect DNA repair and cause diseases?

3. W H AT A R E G - Q U A D R U P L E X E S ?
• G-quadruplexes (G4s) are structures
formed by guanine-rich nucleic-acid
sequences
• G4s are susceptible to oxidative DNA
damage
• 8-oxoGuanine modified sequences still
fold into stable G4s
• G4s disrupts DNA replication, repair, and
RNA translation
Guanine 8-oxoGuanine
G-quadruplex conformation
Guanine tetrad
Source: G-quadruplex for luminescent sensing and logic
gates

4. FA N C J H E L I C A S E
FANCJ Background:
• Is one of 23 proteins within the Fanconia
Anemia DNA repair pathway
• Repairs interstrand DNA cross-links
• Mutations of this protein cause Fanconia
Anemia
• Bone marrow failure
• Heart defects
• Increased susceptibility to cancer
• Unfolding of G4s
(Wu & Spies 2016)
1. Wu, Colin G., and Maria Spies. “G-Quadruplex Recognition and Remodeling by the FANCJ Helicase.” Nucleic Acids Research 44.18 (2016): 8742–8753. PMC.

5. HYPOTHESIS
• FANCJ alleviates oxidative damage in
heart muscle cells
METHODS
• Use video-based detection method to
monitor the beating of iPSC-
cardiomyocytes under oxidative stress
• Transiently transfect FANCJ into human
cardiomyocytes
• Use single-cell electrophoresis to
determine the amount of DNA damage
within the cell

7. T R E AT M E N T O F I P S C -
C A R D I O M Y O C Y T E S
• Cells are plated on a 6-
well plate
• CMs were then treated
with hydrogen peroxide
(H2O2)
• The contractile motion
was then monitored using
video analysis

8. C O N T R O L
Parameter Summary
Beat Rate(bpm) 29
Minimum Beat Rate(bpm) 16
Maximum Beat Rate(bpm) 33
Velocity (pixels/sec) 4.1
Contraction Time(sec) 0.7
RelaxationTime(sec) 0.8
Prevalence(%) 94.4

9. C O N T R A C T I L E F U N C T I O N
R E S U LT S
• Beat rate increases with the increase in
hydrogen peroxide concentration
• Decrease in the number of beating cells
(prevalence) in the presence of
hydrogen peroxide.
3 5 0 U M H 2 O 2
Parameter Summary
Beat Rate(bpm) 36
Minimum Beat Rate(bpm) 33
Maximum Beat Rate(bpm) 45
Velocity (pixels/sec) 3.2
Contraction Time(sec) 0.3
RelaxationTime(sec) 0.5
Prevalence(%) 89.9

10. S I N G L E - C E L L E L E C T R O P H O R E S I S A S S A Y “ C O M E T
A S S A Y ”

11. C O M E T A S S AY R E S U LT S
GFP-FANCJ transfection
• HCMs exhibit a higher sensitivity to hydrogen peroxide for DSBs
• FANCJ reduces the sensitivity to DSBs
HCM H2O2 Neutral Assay (DSB)
% DNA Damage
0 20 40 60 80
Count
0
10
20
30
40
50
150uM H2O2
250uM H2O2
350uM H2O2
Control
HCM H2O2 Alkaline Assay (SSB)
% DNA Damage
0 10 20 30 40 50 60 70 80
Count
0
20
40
60
80
100
120
140
350uM H2O2
150uM H2O2
Control
250uM H2O2
FANCJ HCM Neutral Assay
%DNA Damage
0 20 40 60 80 100
Count
0
2
4
6
8
10
12
14
Control
150uM H2O2
250uM H2O2
350uM H2O2

12. C O N C L U S I O N S F U T U R E D I R E C T I O N S
• iPSC-CMS experience more an increase
in beat rate when under oxidative stress
• HCMs are more sensitive to DSBs
generated by hydrogen peroxide than
SSBs
• FANCJ reduces the sensitivity of DSB
caused by oxidative stress
• Test the cardiovascular effects of FANCJ
mutations under oxidative stress conditions

13. • This work is supported by:
• American Heart Association to C.G.W.
• 19AIREA34460026
• 18IPA34170477
• 17AIREA33661285
• O.U Graduate Provost Award to K.L
• MSCG Graduate Fellowship to K.L
• King-Chavez-Parks Fellowship to K.L
• Thank you to Dr. Wu and colleagues in the
Wu Lab for their continuous support.
ACKNOWLEDGEMENTS/REFERENCES