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Determining the Role of GPX, an
antixodant, in the Inflammatory Changes
Associated with Emphysema
Navida Bholanauth
Dr. Jeanine D’Armiento
Columbia University
Emphysema
• Definition: Pathological disease characterized
by the abnormal enlargement of the distal
airspaces of the lung.
• Cigarette smoking is the major factor associated
with development of emphysema.
• Age Adjusted Mortality for COPD has increased
by 71% between 1966 and 1995.
• 24 million Americans affected with 119,000
deaths annually.
• 32.1 billion dollars in costs annually in this
country.
Oxidants and COPD
• Each puff of smoke contain 1014 free radicals
• Free radicals cause direct damage to lipids,
proteins and DNA
• Oxidants induce lung epithelial cells to release
cytokines IL-1, IL-8 and TNF-α
• Induce influx of inflammatory cells
• Hypothesis: An oxidant/antioxidant imbalance
can lead to the development of emphysema
Some Common Sources of
Antioxidants
• Vitamin E
• Vitamin C
• Selenium
Antioxidants and Lung
• Rich network of antioxidants to protect the lung
• Antioxidants are increased in response to
cigarette smoke
• Antioxidant responses are quite variable
• Differences in antioxidant responses may
account for differences in disease susceptibility
• Epidemiologic data links antioxidants to COPD
symptoms and disease severity (MORGEN
Study).
Antioxidants and the Lung
Kinnula, AJRCCM 2003
Experimental Protocol
• Mice that expressed human GPX1 were bred on
a C57xCBA background
• Gene was under control of the mouse HMG CoA
reductase promoter
• The activity of the enzyme was increased 3.9
fold in the lungs of transgenic mice
• Transgenic and littermate control mice were
exposed to chronic cigarette smoke
• Comparative analyses were made with nonexposed transgenic and control mice.
Research Aims
• Determine the effect of GPX1 expression
on the induction of inflammation by
cigarette smoke.
• Evaluate the effect of GPX1 on smokemediated emphysema formation.
Glutathione Peroxidase-1 Decreases
Smoke Induced Macrophage Influx
90
Macrophages x 10,000
80
70
60
50
40
30
20
10
0
control
smoke
__________
control
smoke
__________
Wild-type
GPX1
Glutathione Peroxidase-1 Decreases
Smoke Induced Neutrophil Influx
140000
Lung Lavage Neutrophils
120000
100000
80000
60000
40000
20000
0
Wild-type
SM
GPX
SM
Control
WT
GPX1
Smoke Exposed
GPX1 Prevents Cigarette Smoke-Induced Emphysema
65
Mean Linear Intercept (MLI)
60
55
*
50
45
40
35
30
Con
Sm
Wild-type
Con Sm
GPX1
Summary of Findings
• GPX1 expression in the lung prevented
the inflammatory response to cigarette
smoke exposure.
• The expression of GPX1 protected against
the development of smoke-induced
emphysema.
• The major research goals are to determine
the how GPX1 expression regulates
smoke-induced inflammation.
Oxidant Signaling and Inflammatory Cell
Recruitment
• MAPK signaling
-T cell differentiation and activation
-induction of cellular adhesion molecules and
chemokines
-p38 inhibition decreased neutrophilia in
response to cigarette smoke exposure
• NF-kB
-regulates the expression of pro inflammatory
genes
Smoke-Derived Oxidants and MAPK Activation
Figure 1.Oxidants and MAPK Activation
P
EGFR
MEKK
P
Raf
Ras
P
P
Raf
Ras
P
MKP
MEKK
MAPK
P
MAPK
c-Jun
P
c-Jun
P
c-Jun
Transcription Factor Activation
(e.g. CBP, STAT, cMyc, SP1, NFAT)
AP-1 Site
Smoke-Derived Oxidants and NF-κB Activation
Figure 2.
ROS
02, H2O2, NO, CO,
Quinones(Q/Q•-/QH2)
IKK
PTK
IkB Phos
P
IkB
P
IkB
p50
RelA
IkB
p50
p50
P
P
RelA P
RelA P
Inflammatory gene induction
degradation
Chronic Effects of Cigarette Smoke on MAPK Activation
Wild-type
GPX1 Transgenic
p-JNK
p38
p-ERK
Actin
_____________
control
_____________
smoke-exposed
_____________
control
_____________
smoke-exposed
Chronic Effects of GPX1 and Cigarette Smoke on NF-κB Activation
Wild-type
GPX1 Transgenic
p-IκB
Actin
_____________ _____________ _____________ _____________
control
control
smoke-exposed
smoke-exposed
Results
• Lungs of GPX mice have less emphysematous changes
than wildtype smoke exposed mice.
• Inflammatory markers, macrophages and neutrophils,
are decreased in the lungs of GPX mice as compared to
wildtype smoke exposed mice.
• P-JNK and P-38 seem to be regulated with smoke
exposure.
• GPX as compared to WT have less p-38 and p-JNK at
baseline and increase with smoke exposure but less
than wildtype smoke exposed mice.
• There is no regulation of IκB with smoke exposure in
wildtype mice and less for GPX baseline and smoke
exposed mice.
Conclusions
• Smoke exposed GPX mice seem to display less
emphysematous changes in than smoke
exposed wildtype mice.
• There is a marked decrease in inflammation in
GPX mice after smoke exposure.
• Though there seems to be regulation with p38
and pJNK, further studies need to be done to
see why GPX mice have less baseline levels of
these markers and what that means during
smoke exposure.
Mentor
Jeanine D’Armiento
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Robert Foronjy
Vincent Lemaitre
Tina Zelonina
Jincy Thankachen
Alison Wallace
Mark Maxfield
Divya Mehra
David Sternberg
Polina Golovach
Summer Students: Leslie,
Nakisha & Enoelia
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Collaborators
Oleg Mirochnitchenko
Olga Propokenko
Yasunori Okada
Masayori Inouye
Kazushi Imai
References
• Author name et al. Year. Name of Journal
(abbreviation at bottom).