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Author Notes:

Bashar S. Staitieh, MD, Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University School of Medicine, 615 Michael Street, Suite 205, Atlanta, GA 30322, Tel: (404) 727-3025, Fax: (404) 712-2974, bashar.staitieh@emory.edu.

Conception and Design (BSS, EEE, DMG, XF); Performing Experiments (BSS, EEE, AA); Data Analysis (BSS, EEE); Drafting and Revising of Manuscript (BSS, EEE, DMG, XF)

The authors gratefully acknowledge the technical support provided by Robert Raynor and S. Todd Mills.

Authors have no conflicts of interest to declare.

Subject:

Research Funding:

Dr. Staitieh was supported by K08 AA 024512; Dr. Egea and Ms. Amah were supported by T32 HL116271; and Dr. Guidot was supported by R01 AA 017627.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Medicine, General & Internal
  • General & Internal Medicine
  • Alcohol
  • RAGE
  • Alveolar macrophage
  • Antioxidant
  • Innate immunity
  • CHRONIC ETHANOL INGESTION
  • OXIDATIVE STRESS
  • DYSFUNCTION
  • RECEPTOR
  • LUNG
  • GLUTATHIONE
  • ABUSE
  • CELL

Chronic Alcohol Ingestion Impairs Rat Alveolar Macrophage Phagocytosis via Disruption of RAGE Signaling

Tools:

Journal Title:

American Journal of the Medical Sciences

Volume:

Volume 355, Number 5

Publisher:

, Pages 497-505

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Background: Alcohol significantly impairs antioxidant defenses and innate immune function in the lung and increases matrix metalloproteinase 9 (MMP-9) activity. The receptor for advanced glycation end products (RAGE) is a well-characterized marker of lung injury that is cleaved by MMP-9 into soluble RAGE and has not yet been examined in the alcoholic lung. We hypothesized that chronic alcohol ingestion would impair RAGE signaling via MMP-9 in the alveolar macrophage and thereby impair innate immune function. Materials and Methods: Primary alveolar macrophages were isolated from control-fed or alcohol-fed rats. Real-time polymerase chain reaction (qRT-PCR), Western blotting, and enzyme-linked immunosorbent assays were performed to evaluate RAGE expression. Silencing of MMP-9 ribonucleic acid (RNA) in a rat alveolar macrophage cell line was confirmed by qRT-PCR, and immunofluorescence (IF) was used to assess the association between alcohol, MMP-9, and RAGE. Phagocytosis was assessed using flow cytometry. Sulforaphane and glutathione were used to assess the relationship between oxidative stress and RAGE. Results: RAGE messenger RNA expression was significantly increased in the alveolar macrophages of alcohol-fed rats, but IF showed that membrane-bound RAGE protein expression was decreased. Lavage fluid demonstrated increased levels of soluble RAGE (sRAGE). Decreasing MMP-9 expression using si-MMP-9 abrogated the effects of alcohol on RAGE protein. Phagocytic function was suppressed by direct RAGE inhibition, and the impairment was reversed by antioxidant treatment. Conclusions: Chronic alcohol ingestion reduces RAGE protein expression and increases the amount of sRAGE in alveolar lavage fluid, likely via cleavage by MMP-9. In addition, it impairs phagocytic function. Antioxidants restore membrane-bound RAGE and phagocytic function.

Copyright information:

© 2017 Southern Society for Clinical Investigation

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