Impact of hyperglycemia on phospholipase C and phospholipase D expression in neutrophil-like HL-60 cells
Date
2012
DOI
Authors
Suwid, Abdelrouf Otman
Version
OA Version
Citation
Abstract
Diabetes mellitus is a metabolic disorder characterized by hyperglycemia and altered function of polymorphonuclear neutrophils. Uncontrolled diabetes leads to increased inflammation and oxidative stress, PMN priming and tissue damage. The aim of this study was to evaluate the expression of phosphoionositide-specific phospholipase C (PLC) and phosphatidylcholine-specific phospholipase D (PC-PLD) in polymorphonuclear neutrophils (PMN). Based on the previous work, we also hypothesized that there is a cross-talk between phospholipase A (PLA) and PLC, PLD in regulation of PMN function. Therefore, the second aim was to study the PLC and PLD expression when PLA2 was inhibited. Expression level of PLC and PLD were evaluated in human promyelocytic leukemic cells (HL-60 cells) which were differentiated into neutrophil-like cells. HL-60 cells were cultured for six days and cultured in diabetic conditions by adding 25mM glucose to the medium to replicate hyperglycemia and 5 mega/ml S100B RAGE ligand to initiate the effect of AGE. Expression of PLC[Beta]2, PLCy1, PLD1, and PLD2 were measured at RNA level using real time PCR at 2, 8, and 24 hours in the presence or absence of a specific calcium independent iPLA2 inhibitor (BEL).
PLC[Beta]2, which is responsible of cytosolic calcium influx and PKC phosphorylation, was elevated at 8 hours and further increased after inhibiting iPLA2. Py1 significantly increased at 8 hours. PLD1, which catalyzes the hydrolysis of the terminal diester of bond of glycerophospholipids leading to the formation of phosphatidic acid and phosphorylate PKC, was also significantly increased while there was no impact on the PLD2 expression. The findings of this study showed that hyperglycemia causes an up-regulation of various forms of PLC and PLD and there could be a redundancy where PLC expression increases in the absence of iPLA subscript 2.
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Dissertation (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Periodontology and Oral Biology).
Includes bibliography: leaves 49-57.
Dissertation (MSD) --Boston University, Henry M. Goldman School of Dental Medicine, 2012 (Department of Periodontology and Oral Biology).
Includes bibliography: leaves 49-57.
License
This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.