TRANSCRIPTIONAL REGULATION OF OXIDATIVE STRESS IN THE ALCOHOLIC LUNG

1
TRANSCRIPTIONAL REGULATION OF OXIDATIVE STRESS IN
THE ALCOHOLIC LUNG

• Victor Tseng, MD

Division of Pulmonary, Allergy, and Critical Care
Medicine
Mentors Viranuj Sueblinvong, MD and David M.
Guidot, MD
Keywords Alcohol, Oxidative Stess, ATF-3, NRF-2,
TGF-ß
2
CLINICAL PROBLEM

• Alcohol results in severe lung derangements at
  the cellular level1-3
• Decreased alveolar macrophage viability
• Decreased neutrophil chemotaxis
• Increased permeability of alveolar epithelium
• Oxidized intracellular state (low GSH)
• Alcohol renders the lung more susceptible to the
  following acute disease processes4,5
• ALI/ARDS
• Bacterial Pneumonia
• Pulmonary TB (Primary Infection, Reactivation)

3
OXIDATIVE STRESS PATHWAY
ROS?
4
ALCOHOL
HOW?

• Decreased Transcription?
• Epigenetic
• Repression
• Decreased Protein Synthesis?
• RNA interference
• Post-Transcriptional

5

• ATF3
• Ubiquitous transcription factor known to be
  upregulated8 by TGFß1 and then to suppress
  Nrf2-ARE activity in airway smooth muscle cells9,
  whole mouse lung10 and pulmonary fibrosis
  models11.

6

• QUESTION 1
• What transcriptional changes are seen in acute
  and chronic phenotypes of alcohol-induced stress?
• QUESTION 2
• More specifically, is ATF3 involved in this
  process?

7
METHODS (CELLS)
8
METHODS (MICE)
9
RESULTS (Cells, Part 1)
Downregulated Nrf2
For mRNA, alcohol treatment in vitro was
associated with
Upregulated Atf3
Upregulated Tgfß-1
10
RESULTS (Cells, Part 2)
For protein, alcohol treatment in vitro was
associated with
Downregulated GSTT2
Decreased NRF2
11
RESULTS (Mouse Lung)
DownregulatedNrf2
For mRNA, alcohol treatment in vivo was
associated with
Decreased NRF2
Downregulated Atf3
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RESULTS SUMMARY
EFFECTS OF ALCOHOL TREATMENT
3T3 Fibroblasts Whole Lung Lysate
TGFß1 mRNA ??? ???
TGFß1 Proteina ?? ??
Nrf2 mRNA ? ???
Nrf2 Protein ? ???
ATF3 mRNAb ?? ??
ATF3 Protein Pending Pending
a Data not shown b n 2 4, so unable to
determine statistical significance
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LIMITATIONS

• Temporal alcohol exposure is difficult to model
• No good model of chronic alcohol exposure in
  vitro
• No good model of acute alcohol exposure in vivo
• Variation in ATF3 expression can be explained by
  myriad factors
• Genetic regulation of redox homeostasis is
  pleiotropic
• More experiments are needed to confirm trend seen
  in ATF3

14
CONCLUSION

• Alcohol exposure generates oxidative stress via
  an array of transcriptional changes
• TGFß1 expression is upregulated in both 3T3 cells
  and whole mouse lung
• ATF3 expression is upregulated in 3T3 cells, but
  not in whole mouse lung
• As a result, Nrf2-ARE activity and NRF2 protein
  levels are reduced
• These changes may suggest potential therapeutic
  targets in alcohol-mediated ARDS

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ACKNOWLEDGEMENTS

• FUNDING
• NIH K08 AA021404-01
• NIH P50 AA013757
• NIH R01 AA 017627

• RESIDENCY PROGRAM
• Dominique Cosco, MD
• Daniel Dressler, MD
• Megan DeMoss, MD

MENTORS Viranuj Sueblinvong, MD David Guidot,
MD
GUIDOT LAB David Guidot, MD Stephen Mills, MS
Bashar Staitieh, MD Xian Fan, MD Wendy Neveu, MD
PhD
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