Determining the Role of GPX, an antixodant, in the Inflammatory

Changes Associated with Emphysema

Navida BholanauthDr. 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 non-exposed 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 smoke-mediated emphysema formation.

Glutathione Peroxidase-1 Decreases Smoke Induced Macrophage Influx

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Glutathione Peroxidase-1 Decreases Smoke Induced Neutrophil Influx

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GPX1 Prevents Cigarette Smoke-Induced Emphysema

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

P PP P Ras

RasP

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MEKK

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c-Jun c-JunPc-JunP

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AP-1 Site

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Transcription Factor Activation(e.g. CBP, STAT, cMyc, SP1, NFAT)

Figure 1.Oxidants and MAPK Activation

Smoke-Derived Oxidants and MAPK Activation

ROS02, H2O2, NO, CO,

Quinones(Q/Q•-/QH2)

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IkB

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Inflammatory gene induction

Figure 2.

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Smoke-Derived Oxidants and NF-κB Activation

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GPX1 Transgenic Wild-type

Chronic Effects of Cigarette Smoke on MAPK Activation

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Chronic Effects of GPX1 and Cigarette Smoke on NF-κB Activation

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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.

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.

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

References

• Author name et al. Year. Name of Journal (abbreviation at bottom).