QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 18, Issue 1, 14-23, January 2007

This Article Full Text Full Text (PDF) All Versions of this Article: E06-07-0596v1 18/1/14    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ramanathan, M. Articles by Leibovich, S. J. Search for Related Content PubMed PubMed Citation Articles by Ramanathan, M. Articles by Leibovich, S. J.

Synergistic Up-Regulation of Vascular Endothelial Growth Factor (VEGF) Expression in Macrophages by Adenosine A_2A Receptor Agonists and Endotoxin Involves Transcriptional Regulation via the Hypoxia Response Element in the VEGF Promoter

Department of Cell Biology and Molecular Medicine and The Cardiovascular Research Institute, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103

Submitted July 12, 2006; Revised September 29, 2006; Accepted October 18, 2006
Monitoring Editor: Richard Assoian

Macrophages are an important source of vascular endothelial growth factor (VEGF). Adenosine A_2A receptor (A_2AR) agonists with Toll-like receptor (TLR) 2, 4, 7, and 9 agonists synergistically induce macrophage VEGF expression. We show here using VEGF promoter-luciferase reporter constructs that the TLR4 agonist Escherichia coli lipopolysaccharide (LPS) and the A_2AR agonists NECA and CGS21680 synergistically augment VEGF transcription in macrophages and that the HRE in the VEGF promoter is essential for this transcription. We examined whether LPS and/or NECA induce HIF-1 expression. HIF-1 mRNA levels were increased in LPS-treated macrophages in an NF-B–dependent manner; NECA strongly increased these levels in an A_2AR-dependent manner. LPS induced luciferase expression from a HIF-1 promoter-luciferase construct in an A_2AR-independent manner. Further stimulation with NECA did not increase HIF-1 promoter activity, indicating that the A_2AR-dependent increase in HIF-1 mRNA is post-transcriptional. LPS/NECA treatment also increased HIF-1 protein and DNA binding levels. Deletion of putative NF-B–binding sites from the VEGF promoter did not affect LPS/NECA-induced VEGF promoter activity, suggesting that NF-B is not directly involved in VEGF transcription. Taken together, these data indicate that LPS/NECA-induced VEGF expression involves transcriptional regulation of the VEGF promoter by HIF-1 through the HRE. HIF-1 is transcriptionally induced by LPS and post-transcriptionally up-regulated in an A_2AR-dependent manner.

Address correspondence to: Samuel Joseph Leibovich (leibovic{at}umdnj.edu)

Abbreviations used: NECA, 5'-N-ethyl-carboxamidoadenosine; CGS21680, 2-[p-(2-carboxylethyl)-phenylethyl amino]-5'-N-ethyl-carboxamido-adenosine; LPS, lipopolysaccharide; HRE, hypoxia response element; HIF, hypoxia inducible factor; MTT, methyl thiazole tetrazolium.

This article has been cited by other articles:

				L. Tacchini, E. Gammella, C. De Ponti, S. Recalcati, and G. Cairo Role of HIF-1 and NF-{kappa}B Transcription Factors in the Modulation of Transferrin Receptor by Inflammatory and Anti-inflammatory Signals J. Biol. Chem., July 25, 2008; 283(30): 20674 - 20686. [Abstract] [Full Text] [PDF]

				L. Wang and B. Damania Kaposi's Sarcoma-Associated Herpesvirus Confers a Survival Advantage to Endothelial Cells Cancer Res., June 15, 2008; 68(12): 4640 - 4648. [Abstract] [Full Text] [PDF]

				C. Graf, B. Zemann, P. Rovina, N. Urtz, A. Schanzer, R. Reuschel, D. Mechtcheriakova, M. Muller, E. Fischer, C. Reichel, et al. Neutropenia with Impaired Immune Response to Streptococcus pneumoniae in Ceramide Kinase-Deficient Mice J. Immunol., March 1, 2008; 180(5): 3457 - 3466. [Abstract] [Full Text] [PDF]

				L. Macedo, G. Pinhal-Enfield, V. Alshits, G. Elson, B. N. Cronstein, and S. J. Leibovich Wound Healing Is Impaired in MyD88-Deficient Mice: A Role for MyD88 in the Regulation of Wound Healing by Adenosine A2A Receptors Am. J. Pathol., December 1, 2007; 171(6): 1774 - 1788. [Abstract] [Full Text] [PDF]

				M. Nasimuzzaman, G. Waris, D. Mikolon, D. G. Stupack, and A. Siddiqui Hepatitis C Virus Stabilizes Hypoxia-Inducible Factor 1{alpha} and Stimulates the Synthesis of Vascular Endothelial Growth Factor J. Virol., October 1, 2007; 81(19): 10249 - 10257. [Abstract] [Full Text] [PDF]

				C. De Ponti, R. Carini, E. Alchera, M. P. Nitti, M. Locati, E. Albano, G. Cairo, and L. Tacchini Adenosine A2a receptor-mediated, normoxic induction of HIF-1 through PKC and PI-3K-dependent pathways in macrophages J. Leukoc. Biol., August 1, 2007; 82(2): 392 - 402. [Abstract] [Full Text] [PDF]

				J. N. Kline Eat Dirt: CpG DNA and Immunomodulation of Asthma Proceedings of the ATS, July 1, 2007; 4(3): 283 - 288. [Abstract] [Full Text] [PDF]