Download - Determining the Role of GPX, an antixodant, in the Inflammatory Changes Associated with Emphysema
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Determining the Role of GPX, an antixodant, in the Inflammatory
Changes Associated with Emphysema
Navida BholanauthDr. Jeanine D’Armiento
Columbia University
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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.
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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
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Some Common Sources of Antioxidants
• Vitamin E
• Vitamin C
• Selenium
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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).
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Antioxidants and the Lung
Kinnula, AJRCCM 2003
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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 non-exposed transgenic and control mice.
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Research Aims
• Determine the effect of GPX1 expression on the induction of inflammation by cigarette smoke.
• Evaluate the effect of GPX1 on smoke-mediated emphysema formation.
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Glutathione Peroxidase-1 Decreases Smoke Induced Macrophage Influx
0
10
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Mac
rop
hag
es x
10,
000
control smoke control smoke __________ Wild-type
__________ GPX1
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Glutathione Peroxidase-1 Decreases Smoke Induced Neutrophil Influx
0
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140000L
un
g L
avag
e N
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tro
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Wild-type GPX SM SM
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Control Smoke Exposed
WT
GPX1
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30
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65M
ean
Lin
ear
Inte
rcep
t (M
LI)
Wild-type GPX1
*
Con Sm Con Sm
GPX1 Prevents Cigarette Smoke-Induced Emphysema
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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.
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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
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P PP P Ras
RasP
RafRafP
MEKK
MEKKP
MAPK MAPKP
c-Jun c-JunPc-JunP
c-JunPc-JunP
AP-1 Site
EGFR
MKP
Transcription Factor Activation(e.g. CBP, STAT, cMyc, SP1, NFAT)
Figure 1.Oxidants and MAPK Activation
Smoke-Derived Oxidants and MAPK Activation
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ROS02, H2O2, NO, CO,
Quinones(Q/Q•-/QH2)
p50
IkB
RelAp50
IkB
RelA
IKK IkB Phos
IkB
PP
p50RelA P
IkB
PP
p50RelA P
degradation
Inflammatory gene induction
Figure 2.
PTK
Smoke-Derived Oxidants and NF-κB Activation
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p38
Actin
p-JNK
GPX1 Transgenic Wild-type
Chronic Effects of Cigarette Smoke on MAPK Activation
_____________ control
_____________smoke-exposed
_____________ control
_____________smoke-exposed
p-ERK
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Wild-type GPX1 Transgenic
p-IκB
Actin
Chronic Effects of GPX1 and Cigarette Smoke on NF-κB Activation
_____________ control
_____________smoke-exposed
_____________ control
_____________smoke-exposed
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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.
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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.
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MentorJeanine D’Armiento
• Robert Foronjy• Vincent Lemaitre• Tina Zelonina• Jincy Thankachen• Alison Wallace• Mark Maxfield• Divya Mehra• David Sternberg• Polina Golovach• Summer Students: Leslie,
Nakisha & Enoelia
Collaborators• Oleg Mirochnitchenko• Olga Propokenko• Yasunori Okada• Masayori Inouye• Kazushi Imai
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References
• Author name et al. Year. Name of Journal (abbreviation at bottom).