PT  - JOURNAL ARTICLE
AU  - DIMITRIOS J. KONDOMERKOS
AU  - STEFANOS A. KALAMIDAS
AU  - LAMPROS K. MICHALIS
AU  - PANAGIOTIS KANAVAROS
TI  - The Effects of Phosphoinositide/Calcium- or Cyclic AMP-mediated Signal Transduction Pathway Inhibitors on the Activation of Rat Peritoneal Macrophages by Acetylated Low-density Lipoprotein
DP  - 2004 Sep 01
TA  - In Vivo
PG  - 653--660
VI  - 18
IP  - 5
4099  - http://iv.iiarjournals.org/content/18/5/653.short
4100  - http://iv.iiarjournals.org/content/18/5/653.full
SO  - In Vivo2004 Sep 01; 18
AB  - Background: Macrophages that uptake modified lipoproteins are activated and may initially behave as endotoxin-stimulated macrophages. This study was undertaken in order to determine whether signal transduction pathways controlling endotoxin-mediated activation may also influence the lipoprotein-mediated activation of macrophages. Materials and Methods: Rat peritoneal macrophages were incubated for 16 hours with acetylated low-density lipoprotein and certain agents that modify the phosphoinositide/calcium- and cyclic AMP-mediated pathways, such as 2-[4-morpholinyl]-8-phenyl-1[4H]-benzopyran-4-one (LY-294002), autocamtide 2-related inhibitory peptide (AIP), N-(2-[p-bromocinnamylamino]-ethyl)-5-isoquinolinesulfonamide hydrochloride (H-89) and actinomycin D. The production of nitric oxide and the intracellular and extracellular activities of acid phosphatase were assayed. Results: Macrophages incubated with acetylated low-density lipoprotein showed an increased production of nitric oxide and intracellular acid phosphatase activity as compared to their controls. LY-294002, AIP and H-89 caused a significant decrease in nitric oxide production and intracellular acid phosphatase activity. Actinomycin D had similar effects. AIP and actinomycin also significantly increased extracellular acid phosphatase activity. Conclusion: The activation of peritoneal macrophages by acetylated low-density lipoprotein was similar to the activation by endotoxin, as expressed by the nitric oxide production and acid phosphatase intracellular activity; agents controlling the phosphoinositide/calcium- and cyclic AMP-mediated pathways in endotoxin-activated macrophages also influence the acetylated low-density lipoprotein-activated macrophages. Copyright © 2004 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved