Phospholipase Activities in Clinical and Environmental Isolates of Acanthamoeba
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The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phospholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase A2 (PLA2) and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA2. Acanthamoeba exhibited optimal phospholipase activities at 37˚C and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA2-specific inhibitor, i.e., cytidine 5´-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.
Abstract
The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phospholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase A2 (PLA2) and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA2. Acanthamoeba exhibited optimal phospholipase activities at 37˚C and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA2-specific inhibitor, i.e., cytidine 5´-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.
참고문헌 (28)
- Khan NA, "Acanthamoeba: biology and increasing importance in human health", FEMS Microbiol Rev, 30(564), pp.564~595 (2006)
- Marciano-Cabral F, "Acanthamoeba spp. as agents of disease in humans", Clin Microbiol Rev, 16, pp.273~307 (2003)
- Schuster FL, "Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals", Int J Parasitol, 34, pp.1001~1027 (2004)
- Jung SY, "Pathogen–pathogen interactions: a comparative study of Escherichia coli interactions with the clinical and environmental isolates of Acanthamoeba", World J Microbiol Biotechnol, 24, pp.2339~2348 (2008)
- Victoria EJ, "Plasma membrane and soluble lysophospholipases of Acanthamoeba castellanii", Arch Biochem Biophys, 171, pp.255~258 (1975)
- Victoria EJ, "Enzymes of phospholipid metabolism in the plasma membrane of Acanthamoeba castellanii", J Lipid Res, 16, pp.54~60 (1975)
- Cursons RTM, "Virulence of pathogenic free-living amoebae", J Parasitol, 64, pp.744~745 (1978)
- Ghannoum MA, "Potential role of phospholipases in virulence and fungal pathogenesis", Clin Microbiol Rev, 13, pp.122~143 (2000)
- Exton JH, "regulation and function", Rev Physiol Biochem Pharmacol, 144, pp.1~94 (2002)
- McDermott M, "Phospholipase D", Biochem Cell Biol, 82, pp.225~253 (2004)
- Akiba S, "Cellular function of calcium-independent phospholipase A2", Biol Pharm Bull, 27, pp.1174~1178 (2004)
- Kudo I, "Diversity of phospholipase A2 enzymes. Foreword", Biol Pharm Bull, 27, pp.1157~ (2004)
- Sissons J, "Acanthamoeba castellanii induces host cell death via a phosphatidylinositol 3-kinase-dependent mechanism", Infect Immun, 73, pp.2704~2708 (2005)
- Stins MF, "Selective expression of adhesion molecules on human brain microvascular endothelial cells", J Neuroimmunol, 76, pp.81~90 (1997)
- Alsam S, "Acanthamoeba interactions with human brain microvascular endothelial cells", Microb Pathog, 35, pp.235~241 (2003)
- Matin A, "Balamuthia mandrillaris exhibits metalloprotease activities", FEMS Immunol Med Microbiol, 47, pp.83~91 (2006)
- Sissons J, "Ecto-ATPases of clinical and non-clinical isolates of Acanthamoeba", Microb Pathog, 37, pp.231~239 (2004)
- Leher H, "Mannose induces the release of cytopathic factors from Acanthamoeba castellanii", Infect Immun, 66, pp.5~10 (1998)
- Dennis EA, "Role of phospholipase in generating lipid second messengers in signal transduction", FASEB J, 5, pp.2068~2077 (1991)
- Serhan CN, "Lipid mediator networks in cell signaling: update and impact of cytokines", FASEB J, 10, pp.1147~1158 (1996)
- Oishi K, "Regulation of protein kinase C by lysophospholipids. Potential role in signal transduction", Biol Chem, 263, pp.6865~6871 (1988)
- Bryant AE, "Phospholipase C and perfringolysin O from Clostridium perfringens upregulate endothelial cell-leukocyte adherence molecule 1 and intercellular leukocyte adherence molecule 1 expression and induce interleukin-8 synthesis in cultured human umbilical vein endothelial cells", Infect Immun, 64, pp.358~362 (1996)
- Bunting M, "Alpha toxin from Clostridium perfringens induces proinflammatory changes in endothelial cells", J Clin Invest, 100, pp.565~574 (1997)
- Saffer LD, "The role of phospholipase in host cell penetration by Toxoplasma gondii", Am J Trop Med Hyg, 40, pp.145~149 (1989)
- Long-Krug SA, "Phospholipase A enzymes of Entamoeba histolytica: description and subcellular localization", J Infect Dis, 152, pp.536~541 (1985)
- McNamara PJ, "Targeted mutagenesis of the phospholipase D gene results in decreased virulence of Corynebacterium pseudotuberculosis", Mol Microbiol, 12, pp.921~930 (1994)
- Kameyama S, "The role of alpha-toxin of Clostridium perfringens in experimental gas gangrene in guinea pigs", Jpn J Med Sci Biol, 25, pp.25~200 (1972)
- Häanel H, "New systematically active antimycotics from the beta-blocker category", Mycoses, 38, pp.251~264 (1995)