• View in gallery

    Average percent parasitemia of cytosolic phospholipase A2 (cPLA2)-deficient and control mice after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. K/O = cPLA2-deficient mice; Wild = control mice; DPI = days post-infection.

  • View in gallery

    Average body weight (grams) of cytosolic phospholipase A2 (cPLA2)-deficient (▪) and control mice (♦) after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. DPI = days post-infection.

  • View in gallery

    Survival after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. Dashed line = cytosolic phospholipase A2-deficient mice; Solid line = control mice.

  • View in gallery View in gallery

    Histopathologic evaluations of wild and cytosolic phospholipase A (cpla−/−)-deficient mouse tissues obtained immediately after death (only F is from a mouse without infection with Plasmodium berghei ANKA). A, Wild-type mouse brain showing vascular distension and mononuclear cells and erythrocytes with malarial pigments in the lumen (hematoxylin and eosin stained). B, Brain as in A in a cpla−/− mouse; C, Immunohistochemical analysis of a cpla−/− mouse brain using an MAC-3 monoclonal antibody showing macrophages in distended vascular lumens. D, Brain tissue of wild-type mouse showing microhemorrhage characteristic of cerebral malaria. E, Brain as in D in a cpla−/− mouse. F and G, Immunohistochemical analysis using an anti-cPLA2 polyclonal antibody showing cPLA2 expression in neuronal cells in wild-type mice without (F) and with (G) malarial infection. There is no expression in inflammatory cells in vascular lumen in wild-type mouse with infection. H, Neuronal cells as in G in a cpla−/− mouse. There is almost no non-specific staining with the anti-cPLA2 antibody. I and J, Immunohistochemical analysis of ovaries in wild-type (I) and cpla−/− (J) mice. Results are consistent with those in a previous report.13 K, Spleen in a wild-type mouse showing hyperplastic reactions with numerous immunoblasts, which represent an intense immunologic reaction. L, Spleen as in K in a cpla−/−mouse. M, Lungs of a wild-type mouse showing an increase in macrophages with malaria pigments, but with almost no alveolar exudate or stromal reactions. N, Lungs as in L in a cpla−/− mouse. O, Liver showing numerous Kupffer cells with malarial pigments in a wild-type mouse. P, Liver as in O in a cpla−/− mouse. (Magnification × 200 in A, B, D, E, F, G, H, K, L, M, N, O, and P; × 400 in C; and × 100 in J and I.)

  • 1

    Clark IA, Hunt NH, 1986. Increased production of arachidonate netabolites by peritoneal cells of mice infected with Plasmodium vinckei vinckei.Aust J Exp Biol Med Sci 64 :415–418.

    • Search Google Scholar
    • Export Citation
  • 2

    Weston MJ, Jackman N, Rudge C, Bowles J, Brady C, Bielawska C, O’Grady J, 1982. Prostacyclin in falciparum malaria (letter). Lancet 2 :609.

    • Search Google Scholar
    • Export Citation
  • 3

    Sliwa K, Grundmann HJ, Neifer S, Chaves MF, Sahlmuller G, Blistein-Willinger E, Bienzle U, Kremsner PG, 1991. Prevention of murine cerebral malaria by a stable prostacyclin analog. Infect Immun 59 :3846–3848.

    • Search Google Scholar
    • Export Citation
  • 4

    Xiao L, Patterson PS, Yang C, Lal AA, 1999. Role of eicosanoids in the pathogenesis of murine cerebral malaria. Am J Trop Med Hyg 60 :668–673.

    • Search Google Scholar
    • Export Citation
  • 5

    Perkins DJ, Kremsner PG, Weinberg JB, 2001. Inverse relationship of plasma prostaglandin E2 and blood mononuclear cell cyclooxygenase-2 with disease severity in children with Plasmodium falciparum malaria. J Infect Dis 183 :113–118.

    • Search Google Scholar
    • Export Citation
  • 6

    Deininger MH, Kremsner PG, Meyermann R, Schluesener HJ, 2000. Focal accumulation of cyclooxygenase-1 (COS-1) and COX-2 expressing cells in cerebral malaria. J Neuroimmunol 106 :198–205.

    • Search Google Scholar
    • Export Citation
  • 7

    Murakami M, Nakatani Y, Atsumi G, Inoue K, Kudo I, 1997. Regulatory functions of phospholipase A2. Crit Rev Immunol 17 :225–283.

  • 8

    Uozumi N, Kume K, Nagase T, Nokatani N, Ishii S, Tashiro F, Komagata Y, Maki K, Ikuta K, Ouchi Y, Miyazaki J, Shimizu T, 1997. Role of cytosolic phospholipase A2 in allergic response and parturition. Nature 390 :618–622.

    • Search Google Scholar
    • Export Citation
  • 9

    Bonventre JV, Huang A, Taheri MR, O’Leary E, Li E, Moskowitz MA, Sapirstein A, 1997. Reduced fertility and postischaemic brain injury in mice deficient in cytosolic phopholipase A2. Nature 390 :622–625.

    • Search Google Scholar
    • Export Citation
  • 10

    Nagase Y, Uozumi N, Ishii S, Kume K, Izumi T, Ouchi Y, Shimizu T, 2000. Acute lung injury by sepsis and acid aspiration: a key role for cytosolic phospholipase A2. Nature Immunol 1 :42–46.

    • Search Google Scholar
    • Export Citation
  • 11

    Nogami S, Watanabe J, Nakagaki K, Nakata K, Suzuki H, Suzuki H, Fujisawa M, Kodama T, Kojima S, 1998. Involvement of macrophage scavenger receptors in protection against murine malaria. Am J Trop Med Hyg 59 :843–845.

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    • Export Citation
  • 12

    Kishimoto K, Matsumura K, Kataoka Y, Morii H, Watanabe Y, 1999. Localization of cytosolic phospholipase A2 messenger RNA mainly in neurons in the rat brain. Neuroscience 92 :1061–1077.

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    • Export Citation
  • 13

    Kurusu S, Motegi S, Kawaminami M, Hashimoto I, 1998. Expression and cellular distribution of cytosolic phospholipase A2 in the rat ovary. Prostaglandins Leukot Essent Fatty Acids 58 :399–404.

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    • Export Citation
  • 14

    Murakami M, Kudo I, 2002. Phospholipase A2. J Biochem 131 :285–292.

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    Song C, Chang XJ, Bean KM, Proia MS, Knopf JL, Kriz RW, 1999. Molecular characteriation of cytosolic phopholipase A2-beta. J Biol Chem 274 :17063–17067.

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SHORT REPORT: LETHAL MALARIA IN CYTOSOLIC PHOSPHOLIPASE A2- AND PHOSPHOLIPASE A2IIA-DEFICIENT MICE

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  • 1 Department of Pathology, and Department of Biochemistry and Molecular Biology, The University of Tokyo, Hongo, Tokyo, Japan; Department of Parasitology, Institute of Medical Science, The University of Tokyo, Shirokanedai, Minatoku, Tokyo, Japan; Department of Veterinary Medicine, Nihon University, Kameino, Fujisawa, Kanagawa, Japan; Department of Biochemistry, Gunma University, School of Medicine, Showamachi, Gunma, Japan

Lipid mediators play important roles in the pathogenesis of malaria. Phospholipase A2s are enzymes involved in the production of these mediators, and they function in inflammation. Among them, cytosolic phospholipase A2 (cPLA2) is a key enzyme in the metabolism of arachidonic acid, the first intermediate in the production of lipid mediators. Plasmodium berghei ANKA causes cerebral malaria in CL57B/6 mice, and we recently produced cPLA2-deficient mice with this background. With the expectation of reduced pathogenicity, we performed experimental infection in these mice. Unexpectedly, the infected mice developed cerebral malaria and died at the same time as the control mice, while the parasitemia progressed similarly in both groups. These observations suggest that secretory PLA2s rather than cPLA2 may be involved in the aggravation, although possible compensation by the induction of other enzymes has not been excluded. The present findings are expected to help clarify the involvement of various phospholipase A2s in malaria.

Several lines of evidence indicate that lipid mediators known as eicosanoids are involved in the pathogenesis of malaria. Clark and Hunt showed that peritoneal macrophages from mice infected with murine malaria produced increased amounts of arachidonate metabolites.1 A report of successful treatment of human cerebral malaria with prostaglandin I2 was followed by prevention of murine cerebral malaria by a stable prostaglandin I2 analog.2,3 Intervention in murine malaria with aspirin, a prostaglandin synthesis inhibitor, suggested that prostaglandins are protective against cerebral malaria, while leukotrienes aggravate this disease.4 In human malaria caused by Plasmodium falciparum, the levels of pros-taglandin E2 in plasma and cyclooxygenase-2 in blood mono-nuclear cells are inversely related to disease severity.5 Focal accumulation of cyclooxygenase-1 (COX-1)- and COX-2-expressing cells was reported in human cerebral malaria.6 Cyclooxygenases are the enzymes that convert arachidonic acid to prostaglandins. However, the exact roles of lipid mediators in malaria remain to be elucidated.

Lipid mediators, including prostaglandins and leukotrienes, are all produced from arachidonic acid, which is released from phospholipids in membranes by phospholipase A2s. Phospholipase A2s are enzymes that digest the sn-2 ester bond of phospholipids. Increasing numbers of these enzymes, many of which are involved in inflammation, have been identified. Among them, cytosolic phospholipase A2 (cPLA2) is a key enzyme that is specific for arachidonic acid.7 When activated by micromolar calcium and the phosphorylation of serine by mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), the enzyme is translocated to perinuclear membranes via binding to vimentin. This process is presumed to be important in the production of lipid mediators in inflammation. We have produced cPLA2-deficient mice that displayed reduced bronchial asthma and injury due to cerebral infarction.8–10 Recently, the cPLA2-deficient mice were backcrossed to CL57/B6 mice for 10 generations. It is well established that infection of CL57/B6 with the P. berghei ANKA strain causes severe malaria symptoms in the mice one week after infection, when parasitemia is approximately 20%, resulting in the death of the mice. In contrast, BALB/c or C3H mice survive this period without severe symptoms and die later due to severe anemia and prostration.11

In an attempt to elucidate the mechanisms of aggravation of malaria, we induced experimental infection in cPLA2-deficient mice. We expected that cPLA2-deficient mice would not acquire severe malaria because of the abolition of the production of lipid mediators in inflammation pathways in these mice. However, contrary to our expectation, the infected cPLA2-deficient mice showed severe symptoms and died at just the same time as the control mice.

Eight cpla−/− female mice (6–8 weeks old) and 10 age-matched cpla+/+ mice were used for the experiments. Throughout the experiments, the mice were treated in a humane way. Animals were anesthetized with ether before they were humanely killed. The experiments were performed according to the guidelines of the Animal Center of Nihon University.

The P. berghei ANKA strain was kept frozen in liquid nitrogen and propagated in mice once by intraperitoneal injection. Mice were infected by intraperitoneal injection of 1 × 106 infected erythrocytes into the experimental mice.

Mice were carefully observed twice a day and parasitemia was estimated by evaluating Giemsa-stained slides of thin blood smears made from a drop of tail blood every other day. For pathologic studies, organs were obtained from two cpla−/− mice and three cpla+/+ mice killed on day 6 after infection or from mice under observation immediately after death. Survival of six deficient mice and seven control mice was observed.

Parasitemia showed similar exponential increases in both the deficient and control mice (Figure 1). Body weight remained unchanged during the period of the experiment, which indicated that the mice did not die of prostration (Figure 2). Symptoms in the mice began with coat ruffling and general immobility, followed by partial paralysis, fitting, hyperventilation, coma, and death, the severity of which was essentially the same in both groups.

Survival after challenge infection is shown in Figure 3. Kaplan-Meier analysis of the survival time using the Gehan generalized Wilcoxon method showed that death occurred at a similar time (P = 0.86), with no significant difference between the deficient and the control mice. The weights of various organs (brain, lungs, liver, spleen, and kidneys) showed no significant difference between the two groups, which showed that the pathophysiology, at least in context of malarial infection, is not so different irrespective of the presence or absence of cPLA2.

Extensive pathologic studies of tissues showed remarkable reactive responses in both the deficient and control mice just after death, while essentially the same but milder responses were found in both types of mice killed on day 6 (Figure 4). In brain tissue, several features including microhemorrhage and vascular distention with parasitized erythrocytes and macrophages were seen to the same extent both in wild-type and cpla−/− mice, which is consistent with the neurologic symptoms being equally observed in both groups (Figure 4A–E). In addition to staining with hematoxylin and eosin, immunohistochemical staining using B cell-, T cell-, and macrophage-specific antibodies (Figure 4C) was done. Such staining showed no significant difference in the cellular infiltration pattern between the two groups. The main inflammatory cells in brain tissue were macrophages in the vascular lumen or in the brain parenchyma around microhemorrhage foci. There was a slight increase in T and B lymphocytes in the cerebral vasculature. Immunohistochemical analysis for cPLA2 showed ubiquitous expression of cPLA2 in neuronal cells (Figure 4F–H), which is consistent with the results of a previous report12 in wild-type mice with and without malarial infection. Staining intensity was essentially the same in both groups. There was no expression of cPLA2 in cells in the vascular lumen in infected wild-type mice, which indicates that cPLA2 may not play critical roles in cerebral malaria pathophysiology. In the ovaries, results were consistent with those of a previous report.13 In the spleen, we observed distortion of follicular architecture accompanied by numerous immunoblasts and germinal center formation, which represent intense immunologic reactions (Figure 4L and K). In liver and lungs, there were increases of Kupffer cells and macrophages with malarial pigments (Figure 4M–P). In the lungs, almost no alveolar exudate or stromal response that might have had an effect on mouse survival was found. Overall, there was no significant change that indicated the cause of death, except for several findings compatible with cerebral malaria in both wild-type and cpla−/− mice.

Prostaglandins and leukotrienes are major lipid mediators that function in inflammation. They are produced from arachidonic acid by cyclooxygenases and 5-lipoxygenase, respectively. Arachidonic acid, a key metabolite, is released from phospholipids by phospholipase A2s, which digest the ester bond of the sn-2 fatty acids of phospholipids. A growing number of phospholipase A2s have been identified. They are divided into secretory, cytosolic, and Ca-independent PLA2s.7 Phospholipase A2 was first isolated from pancreatic juice as an enzyme that digests phospholipids in food (group IB PLA2). The 14-kD phospholipase A2IIA was then purified from exudates of animals with experimental inflammation. Subsequent searches of nucleic acid sequence databases resulted in identification of 10 secretory PLA2s. With regard to intracellular PLA2s, cPLA2 alpha was cloned as a high molecular weight PLA2.7,14

Cytosolic phospholipase A2 alpha is an 85-kD molecule located ubiquitously in the cytoplasm of all cell types examined except for mature lymphocytes.7 cPLA2 beta and cPLA2 gamma have also been cloned. cPLA2 alpha and cPLA2 beta have an N-terminal C2 domain, which is critical for a Ca2+-dependent association with phospholipid membranes. cPLA2 gamma contains an isoprenylation site for membrane binding. Activated cPLA2 specifically releases arachidonic acid, which is metabolized to prostaglandins and leukotrienes. Because this is the first enzyme in the cascade leading to the production of various lipid mediators, its deficiency is thought to abolish the subsequent production of prostaglandins and leukotrienes. Actually, cPLA2-deficient mice show marked reductions in the production of prostaglandin E2, leukotriene B4, and leukotriene C4 by activated peritoneal macrophages.8,9

Although the unexpected results obtained in the present study are difficult to explain, they provide the basis for some speculations about the responsible mechanism. One possibility is that the enzyme deficiency was compensated for by the induction of cPLA2beta, cPLA2gamma, or hitherto unidentified enzyme(s).15,16 However, if one considers the difference between the localization of cPLA2 beta and cPLA2 gamma in normal tissues and that of cPLA2 alpha, this seems unlikely.

Conversely, it is well known that secretory PLA2s IIA and V (sPLA2) are involved in inflammation and protection against bacterial infection.17 In both adult and juvenile malaria patients, an increased level of phospholipase A2 has been reported.18,19 The increased enzyme level was shown immunologically to be group II secretory phospholipase A2. Whether this enzyme is protective against malaria or simply associated with the disease is unknown. The mice used in our experiments are also deficient in phospholipase IIA due to a frame shift mutation in the corresponding gene.20 Infection with P. berghei ANKA causes accelerated death in CL57B/6 and 129SvJ mice, which are phospholipase IIA deficient. However, C3H and BALB/c mice, which have normal phospholipase IIA, survive the early phase of this infection and die later due to severe anemia and prostration.11 One reported exception to this pattern are B10.RIII mice, which have a defective phospholipase IIA gene but which rarely acquire cerebral malaria.21 Since the deficient mice used in the present study were originally produced in strain 129/SvJ, which is also phospholipase IIA deficient, and backcrossed with CL57B/6, they are deficient in this enzyme. These observations suggest the intriguing hypothesis that increased phospholipase A2 IIA is protective against severe malaria, and that accelerated death is associated with its deficiency.20,21 Further studies will be necessary to test this hypothesis.

Other secretory PLA2s are also involved in signal transduction in inflammation. The most striking example is that phospholipase IB receptor-deficient mice are resistant to lipo-polysaccharide (LPS)-induced septic shock.22 Interestingly, this receptor binds only activated sPLA2 IB, but not the inactive enzyme containing a prepropeptide, indicating its biologic relevance. Furthermore, it has been shown that secretory PLA2 X, which also has a prepropeptide, is a natural ligand of the PLA2 IB receptor and induces a potent release of arachidonic acid from spleen cells.23,24 Released secretory PLA2s are bound by this receptor, taken up into the cytoplasm, and then induce inflammatory pathways. Mice with an intact PLA2 IB receptor die rapidly when treated with LPS, whereas control mice survive. Treatment with LPS causes similar pathogenic effects to murine malaria in many respects, including effects such as an increase in tumor necrosis factor-α or interleukin-1β. The possible involvement of sPLA2 IB receptor in malaria is also of great interest.

Recently, the use of genome-wide polymorphism markers resulted in the mapping of the genetic loci in mice that are responsible for the control of parasitemia and cerebral malaria.25–27 This novel approach is expected to provide a powerful tool to decipher the genetic basis of malaria resistance. However, gene knockout mice are important for pinpointing the critical gene(s) involved in resistance to and pathogenesis of malaria.

In conclusion, experimental infection of cPLA2- and PLA2 IIA-deficient mice in a CL57B/6 background resulted in the rapid death of these mice, as it did in control mice. It is expected that further studies of phospholipase A2s will reveal more details of the pathogenesis of lethal malaria and the involvement of lipid mediators.

Figure 1.
Figure 1.

Average percent parasitemia of cytosolic phospholipase A2 (cPLA2)-deficient and control mice after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. K/O = cPLA2-deficient mice; Wild = control mice; DPI = days post-infection.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 70, 6; 10.4269/ajtmh.2004.70.645

Figure 2.
Figure 2.

Average body weight (grams) of cytosolic phospholipase A2 (cPLA2)-deficient (▪) and control mice (♦) after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. DPI = days post-infection.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 70, 6; 10.4269/ajtmh.2004.70.645

Figure 3.
Figure 3.

Survival after challenge infection with 106 Plasmodium berghei ANKA parasites by intraperitoneal injection. Dashed line = cytosolic phospholipase A2-deficient mice; Solid line = control mice.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 70, 6; 10.4269/ajtmh.2004.70.645

Figure 4.
Figure 4. Figure 4.

Histopathologic evaluations of wild and cytosolic phospholipase A (cpla−/−)-deficient mouse tissues obtained immediately after death (only F is from a mouse without infection with Plasmodium berghei ANKA). A, Wild-type mouse brain showing vascular distension and mononuclear cells and erythrocytes with malarial pigments in the lumen (hematoxylin and eosin stained). B, Brain as in A in a cpla−/− mouse; C, Immunohistochemical analysis of a cpla−/− mouse brain using an MAC-3 monoclonal antibody showing macrophages in distended vascular lumens. D, Brain tissue of wild-type mouse showing microhemorrhage characteristic of cerebral malaria. E, Brain as in D in a cpla−/− mouse. F and G, Immunohistochemical analysis using an anti-cPLA2 polyclonal antibody showing cPLA2 expression in neuronal cells in wild-type mice without (F) and with (G) malarial infection. There is no expression in inflammatory cells in vascular lumen in wild-type mouse with infection. H, Neuronal cells as in G in a cpla−/− mouse. There is almost no non-specific staining with the anti-cPLA2 antibody. I and J, Immunohistochemical analysis of ovaries in wild-type (I) and cpla−/− (J) mice. Results are consistent with those in a previous report.13 K, Spleen in a wild-type mouse showing hyperplastic reactions with numerous immunoblasts, which represent an intense immunologic reaction. L, Spleen as in K in a cpla−/−mouse. M, Lungs of a wild-type mouse showing an increase in macrophages with malaria pigments, but with almost no alveolar exudate or stromal reactions. N, Lungs as in L in a cpla−/− mouse. O, Liver showing numerous Kupffer cells with malarial pigments in a wild-type mouse. P, Liver as in O in a cpla−/− mouse. (Magnification × 200 in A, B, D, E, F, G, H, K, L, M, N, O, and P; × 400 in C; and × 100 in J and I.)

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 70, 6; 10.4269/ajtmh.2004.70.645

Authors’ addresses: Shumpei Ishikawa and Masashi Fukayama, Department of Pathology, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033, Japan. Naonori Uozumi and Takao Shimizu, Department of Biochemistry and Molecular Biology, The University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo 113-0033, Takashi Shiibashi and Sadao Nogami, Department of Veterinary Medicine, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-8510, Japan. Takashi Izumi, Department of Biochemistry, Gunma University, 3-39-22 Showamachi, Maebashi, Gunma 371-8511, Japan. Junichi Watanabe, Department of Parasitology, Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan, Telephone: 81-3-5449-5378, Fax: 81-3-5689-3979, E-mail: jwatanab@ims.u-tokyo.ac.jp.

Acknowledgments: We thank Satoko Oguma ( Nihon University) and the staff of the Department of Pathology of The University of Tokyo for helpful assistance. We are grateful to Dr. E. Nakajima for critical reading of the manuscript.

Financial support: The work was partly supported by a Grant-in-Aid for Promotion of Science from The Ministry of Education and Science (14560273).

REFERENCES

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    Clark IA, Hunt NH, 1986. Increased production of arachidonate netabolites by peritoneal cells of mice infected with Plasmodium vinckei vinckei.Aust J Exp Biol Med Sci 64 :415–418.

    • Search Google Scholar
    • Export Citation
  • 2

    Weston MJ, Jackman N, Rudge C, Bowles J, Brady C, Bielawska C, O’Grady J, 1982. Prostacyclin in falciparum malaria (letter). Lancet 2 :609.

    • Search Google Scholar
    • Export Citation
  • 3

    Sliwa K, Grundmann HJ, Neifer S, Chaves MF, Sahlmuller G, Blistein-Willinger E, Bienzle U, Kremsner PG, 1991. Prevention of murine cerebral malaria by a stable prostacyclin analog. Infect Immun 59 :3846–3848.

    • Search Google Scholar
    • Export Citation
  • 4

    Xiao L, Patterson PS, Yang C, Lal AA, 1999. Role of eicosanoids in the pathogenesis of murine cerebral malaria. Am J Trop Med Hyg 60 :668–673.

    • Search Google Scholar
    • Export Citation
  • 5

    Perkins DJ, Kremsner PG, Weinberg JB, 2001. Inverse relationship of plasma prostaglandin E2 and blood mononuclear cell cyclooxygenase-2 with disease severity in children with Plasmodium falciparum malaria. J Infect Dis 183 :113–118.

    • Search Google Scholar
    • Export Citation
  • 6

    Deininger MH, Kremsner PG, Meyermann R, Schluesener HJ, 2000. Focal accumulation of cyclooxygenase-1 (COS-1) and COX-2 expressing cells in cerebral malaria. J Neuroimmunol 106 :198–205.

    • Search Google Scholar
    • Export Citation
  • 7

    Murakami M, Nakatani Y, Atsumi G, Inoue K, Kudo I, 1997. Regulatory functions of phospholipase A2. Crit Rev Immunol 17 :225–283.

  • 8

    Uozumi N, Kume K, Nagase T, Nokatani N, Ishii S, Tashiro F, Komagata Y, Maki K, Ikuta K, Ouchi Y, Miyazaki J, Shimizu T, 1997. Role of cytosolic phospholipase A2 in allergic response and parturition. Nature 390 :618–622.

    • Search Google Scholar
    • Export Citation
  • 9

    Bonventre JV, Huang A, Taheri MR, O’Leary E, Li E, Moskowitz MA, Sapirstein A, 1997. Reduced fertility and postischaemic brain injury in mice deficient in cytosolic phopholipase A2. Nature 390 :622–625.

    • Search Google Scholar
    • Export Citation
  • 10

    Nagase Y, Uozumi N, Ishii S, Kume K, Izumi T, Ouchi Y, Shimizu T, 2000. Acute lung injury by sepsis and acid aspiration: a key role for cytosolic phospholipase A2. Nature Immunol 1 :42–46.

    • Search Google Scholar
    • Export Citation
  • 11

    Nogami S, Watanabe J, Nakagaki K, Nakata K, Suzuki H, Suzuki H, Fujisawa M, Kodama T, Kojima S, 1998. Involvement of macrophage scavenger receptors in protection against murine malaria. Am J Trop Med Hyg 59 :843–845.

    • Search Google Scholar
    • Export Citation
  • 12

    Kishimoto K, Matsumura K, Kataoka Y, Morii H, Watanabe Y, 1999. Localization of cytosolic phospholipase A2 messenger RNA mainly in neurons in the rat brain. Neuroscience 92 :1061–1077.

    • Search Google Scholar
    • Export Citation
  • 13

    Kurusu S, Motegi S, Kawaminami M, Hashimoto I, 1998. Expression and cellular distribution of cytosolic phospholipase A2 in the rat ovary. Prostaglandins Leukot Essent Fatty Acids 58 :399–404.

    • Search Google Scholar
    • Export Citation
  • 14

    Murakami M, Kudo I, 2002. Phospholipase A2. J Biochem 131 :285–292.

  • 15

    Song C, Chang XJ, Bean KM, Proia MS, Knopf JL, Kriz RW, 1999. Molecular characteriation of cytosolic phopholipase A2-beta. J Biol Chem 274 :17063–17067.

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