Signal transducer and activator of transcription 3alpha and specificity protein 1 interact to upregulate intercellular adhesion molecule-1 in ischemic-reperfused myocardium and vascular endothelium.

Abstract

OBJECTIVE:

Intercellular adhesion molecule-1 (ICAM-1) is upregulated rapidly on endothelial cells during ischemia-reperfusion (I-R) and mediates tissue leukocyte accumulation. The ICAM-1 proximal promoter contains a signal transducer and activator of transcription (Stat) binding motif (gamma-interferon activation site [GAS] sequence), which flanks a specificity protein 1 (Sp1) binding site. We examined the roles of Stat and Sp1 in the regulation of ICAM-1 after myocardial I-R.

METHODS AND RESULTS:

Open-chest anesthetized rats underwent coronary artery occlusion for 35 minutes and reperfusion for 0 to 240 minutes. Stat became activated within 15 minutes after reperfusion, primarily in vascular endothelial cells; the activated Stat protein was identified as Stat3 (alpha-isoform). After phosphorylation on serine 727 (p-S727), Stat3alpha was found in association with the transcriptional regulator Sp1, and the complex bound to an ICAM-1-GAS probe. ICAM-1 expression increased after I-R and lagged shortly behind Stat3alpha activation. In cultured human umbilical vein endothelial (HUVE) cells, activation of Stat3alpha after hypoxia-reoxygenation (H-R) was dependent on the small GTPase Rac1. Transfection of a dominant-negative Stat3 (Y705F) adenovirus or a GAS decoy oligonucleotide reduced ICAM-1 mRNA expression after H-R. Using a reporter gene transfected into HUVE cells, mutation of the GAS element in the ICAM-1 promoter resulted in reduced transcriptional activity after H-R. Sp1 coimmunoprecipitated with p-S727 Stat3 during H-R, and Sp1 or Stat3alpha interfering RNA markedly reduced ICAM-1 mRNA expression.

CONCLUSIONS:

The Sp1-Stat3 complex appears to play an important role in the upregulation of ICAM-1 transcription after reoxygenation or reperfusion.

• Authors: Xiao Ping Yang, Kaikobad Irani, Subhendra Mattagajasingh, Anthony Dipaula, Firdous Khanday, Michitaka Ozaki, Karen Fox-Talbot, William M Baldwin 3rd, Lewis C Becker
• Journal: Arteriosclerosis, thrombosis, and vascular biology (Arterioscler Thromb Vasc Biol) Vol. 25 Issue 7 Pg. 1395-400 (Jul 2005) ISSN: 1524-4636 [Electronic] United States
• PMID: 15860735 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Interleukin-6
• RNA, Messenger
• STAT3 Transcription Factor
• Sp1 Transcription Factor
• Intercellular Adhesion Molecule-1
• Tyrosine
• Rac1 protein, rat
• rac1 GTP-Binding Protein

Topics

• Animals
• Cells, Cultured
• Coronary Vessels (cytology, physiology)
• Endothelium, Vascular (cytology, physiology)
• Humans
• Intercellular Adhesion Molecule-1 (genetics)
• Interleukin-6 (pharmacology)
• Male
• Myocardial Reperfusion
• Myocardial Reperfusion Injury (metabolism, physiopathology)
• Phosphorylation (drug effects)
• Promoter Regions, Genetic (physiology)
• RNA Interference
• RNA, Messenger (metabolism)
• Rats
• Rats, Inbred Lew
• STAT3 Transcription Factor (genetics, metabolism)
• Sp1 Transcription Factor (metabolism)
• Transcriptional Activation (physiology)
• Tyrosine (metabolism)
• Umbilical Veins (cytology)
• Up-Regulation (physiology)
• rac1 GTP-Binding Protein (metabolism)