Characterization of the differential expression kinetics of diacylglycerol kinase alpha in localized aggressive periodontitis neutrophils and the human leukemia cell line HL-60

Date
2005
DOI
Authors
Batista, Eraldo L.
Version
OA Version
Citation
Abstract
Localized Aggressive Periodontitis (LAP) is an alteration characterized by progressive and often rapid attachment loss around molars and incisors of adolescents and young adults. Its pathogenesis has been linked to an abnormal response by polymorphonuclear neutrophilis (PMN) to bacterial products characterized by hyper responsive production of superoxide and impaired chemotaxis, leading to severe destruction of the attachment apparatus. These abnormal responses have been previously related to a possible defect in pathways involving lipid second messengers that ultimately regulate production of superoxide. In this context, the lipid second messenger diacylglyerol (DAG) has been shown to be an important activator of protein kinase C (PKC) and superoxide production, DAG is tightly regulated by Diacylglyerol kinases (DGK), a family of enzyme that converts DAG into phosphatidic acid (PA). Previous observations have shown that PMN isolated form LAP subjects present higher levels of DAG, suggesting that, in these patients, the regulatory function of DGK is compromised. The aim of this investigation was to address the role of DGK in the pathogenesis of LAP by characterizing its expression in PMN of LAP and control individuals. Likewise, the HL-60 human leukemia cell line was used to assess the influence of DGK in earlier stages of PMN development, Analysis of the differential expression of DGK revealed that from the 9 isoforms characterized to date (alpha, beta, delta, epsilon, gamma, eta, iota, theta, zeta), only 5 were detected in PMN (alpha, delta, epsilon, gamma, zeta). Quantitative analysis using real-time PCR showed that DGKα presented the higher levels of mRNA among the isoforms expressed. No major variations in the levels of DGK isoforms were found between LAP and control PMN, except for DGKα. The latter isoform was unregulated in LAP PMN and responded to addition of agonists with an increase in the levels of DGKα mRNA that was significantly different from control PMN. Assessment of HL-60 cells induced to differentiate into neutrophil-like cells showed that isoforms [delta], [epsilon], [gamma] and [zeta] increased throughout the differentiation process. DGKα, on the other hand, had lower levels of expression in the undifferentiated state but underwent a significant increase when cells assumed a granulocyte phenotype. [TRUNCATED]
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Thesis (D.Sc.)--Boston University, Henry M. Goldman School of Dental Medicine, 2005 (Oral Biology).
Includes bibliographical references: leaves 127-145.
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