• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.71-78
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• 1997

In an attempt to investigate the role of phospholipase $A_2$($PLA_2$) in interleukin-l (IL-l) induced acute lung injury, mepacrine was tried to inhibit $PLA_2$ in IL-l induced ARDS rats. For confirmation of acute lung injury by IL-l, and to know the role of neutrophils in this injury, lung leak index, lung myeloperoxidase(MPO), number of neutrophils and protein content in the bronchoalveolar lavage (BAL) and wet lung weight were measured. At the same time lung $PLA_2$ was measured to know the effect of IL-l on $PLA_2$ activity. Pulmonary surfactant was also measured for an investigation of type II alveolar cell function. Neutrophil adhesion assay was performed to know the effect of $PLA_2$ inhibition in vitro with human umbilical vein endothelial cells (HUVEC). For precise location of injury by IL-l, morpholgical study was performed by electron microscopy. Five hours after instillation of IL-l (50 ng/rat), lung leak index, protein content, number of neutrophils, lung MPO and wet lung weight were increased significantly. Five hours after IL-l instillation lung $PLA_2$ activity was increased significantly, and increased surfactant release was observed in IL-l induced ARDS rats' BAL. In contrast, in rats given mepacrine and IL-l, there was decrease of acute lung injury i.e. decrease of lung leak index, wet lung weight, protein content, number of neutrophils in BAL and decreased lung MPO activity. Mepacrine decreased surfactant release also. Interestingly, inhibition of $PLA_2$ decreased adhesion of human neutrophils to HUVEC in vitro. Morphologically, IL-l caused diffuse necrosis of endothelial cells, type I and II epithelial cells and increased the infiltration of neutrophils in the interstitium of the lung but after mepacrine treatment these pathological findings were lessened. On the basis of these experimental results it is suggested that $PLA_2$ has a major role in the pathogenesis of acute lung injury mediated by neutrophil dependent manner in IL-l induced acute lung injury.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.21
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• pp.9417-9421
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• 2014

Background: Esophageal cancer is one of the most frequently occurring malignancies and the seventh leading cause of cancer-related deaths in the world. The esophageal squamous cell carcinoma (ESCC) is the most common histological type of esophageal cancer worldwide. Materials and Methods: Our goal in this study was to detect phospholipase A2 Group IIA (PLA2G2A) and cyclooxygenase-2 (COX-2) immuno-expression in ESCC in a high-risk population in China. Results: Positive expression of PLA2G2A protein was observed in 57.2% (166/290) of the cases, while COX-2 was found in 257 of 290 samples (88.6%), both PLA2G2A and COX-2 being expressed in 153 cases (52.8%), with a significant agreement (Kappa=0.091, p=0.031).Overexpression of PLA2G2A was significantly correlated with the depth of invasion (p=0.001). Co-expression of PLA2G2A and COX-2 not only significantly correlated with the depth of invasion (p=0.004) but also with TNM stage (p=0.04). Conclusions: Our results showed that in patients with ESCC, PLA2G2A overexpression and PLA2G2A co-expression with COX-2 is significantly correlated with advanced stage. The biological role and pathophysiologic regulation of PLA2G2A and COX-2 overexpression in ESCC deserve further investigation.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.177-183
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• 2016

We fortuitously observed a human neutrophil intracellular free-calcium concentration ($[Ca^{2+}]_i$) increasing activity in the commercially available phosphodiesterase I (PDE I), which is actually dried crude venom of Crotalus atrox. As this activity was not observed with another commercially available pure PDE I, we tried to find out the causative molecule(s) present in 'crude' PDE, and identified Lys49-phospholipase A2 (Lys49-PLA2 or K49-PLA2), a catalytically inactive protein which belongs to the phospholipase A2 family, by activity-driven three HPLC (reverse phase, size exclusion, reverse phase) steps followed by SDS-PAGE and LC-MS/MS. K49-PLA2 induced $Ca^{2+}$ influx in human neutrophils without any cytotoxic effect. Two calcium channel inhibitors, 2-aminoetoxydiphenyl borate (2-APB) ($30{\mu}M$) and SKF-96365 ($20{\mu}M$) significantly inhibited K49-PLA2-induced $[Ca^{2+}]_i$ increase. These results suggest that K49-PLA2 modulates $[Ca^{2+}]_i$ in human neutrophils via 2-APB- and SKF-96365-sensitive calcium channels without causing membrane disruption.

• Journal of Acupuncture Research
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• v.29 no.1
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• pp.127-137
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• 2012

Objectives : The purpose of this study is to investigate the effect of $Clematidis$ radix herbal-acupuncture solution, on collagen, adjuvant, lipopolysaccharide and phospholipase A2 induced rheumatoid arthritis in mice. Methods : Arthritis index was measured for mouse that was injected subcutaneously in solution mixed chicken type II collagen with Freund's complete adjuvant. We injected Freund's complete adjuvant into right posterior part of the sole of a ICR mouse foot, which was measured by plethysmometer. The solution mixed $CRHS$ with Tris-HCI, $CaCl_2$, substrate, enzyme was done a chemical action for thirty minutes, and then inhibitory activity of PLA2 enzyme was expressed with inhibition percentage by utilizing isolated arachidonic acid. COX-2 was induced by adding LPS to RAW 264.7 cell, and COX-2 activity was measured by western blot analysis and $PGE_2$ Biotrak kit. Results : $CRHS$ also inhibited Freund's complete adjuvant induced chronic rheumatoid arthritis in mice. $CRHS$ showed significant inhibition of type I and type II $PLA_2$ activities in a dose dependent manner. Furthermore, $PGE_2$ production was decreased with $CRHS$ and lipopolysaccharide-induced COX-2 protein expression was significantly inhibited by $CRHS$. Conclusions : These results suggest that $CRHS$ has an therapeutic effect on drug induced-rheumatoic arthritis by inhibiting $PLA_2$ and COX-2 activities.

• Journal of Life Science
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• v.20 no.4
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• pp.474-480
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• 2010

Rutin, a group II phospholipase $A_2$ ($PLA_2$) inhibitor, was tested on interleukin-1 (IL-1) induced acute lung injury (ALI) in male Sprague-Dawley rats. Rutin did not alter the increased lung myeloperoxidase activity by IL-1. However, the number of neutrophils in bronchoalveolar lavage fluid (BALF) and IL-1 induced lung leak were decreased by rutin (p<0.001). Simultaneously, rutin decreased lung $PLA_2$ activity, which was increased by IL-1 (p<0.001). The reduction of neutrophilic respiratory burst by the inhibition of $PLA_2$ was confirmed by group II $PLA_2$ inhibitors such as rutin, manoalide and scalaradial. The increased level of cytokine-induced neutrophilic chemoattractant (CINC) in BALF by IL-1 was not affected by rutin. Ultrastructural changes of ALI and increased generation of free radicals in the lung by IL-1 were found, and rutin ameliorated these pathological findings. Taken together, rutin seems to be effective in decreasing IL-1 induced ALI through inhibition of group II $PLA_2$.

• Childhood Kidney Diseases
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• v.24 no.1
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• pp.36-41
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• 2020

Purpose: Hepatitis B virus (HBV) infection is among etiologies of secondary membranous nephropathy (MN) in pediatric patients. We evaluated expression of phospholipase A2 receptor (PLA2R), a specific target antigen of primary MN, in pediatric HBV-related MN. Methods: We retrospectively reviewed patients with biopsy-proven HBV-related MN from the renal biopsy registry and electronic medical records of Severance Hospital, Seoul, Korea, from 1993 to 2004. Paraffin-embedded human kidney tissues were retrieved and immunohistochemically stained for PLA2R. Results: Ten pediatric patients with 13 biopsied specimens were reviewed. The predominant pathological stage was stage II-III, and second was stage II. The intensity of staining for IgG was greatest, with less intense staining for IgM, IgA, C3, C4, and C1q. All the patients had angiotensin-converting enzyme inhibitor combined with glucocorticoid, and four patients converted to cyclosporine treatment from glucocorticoid monotherapy. Urinalysis of all the patients normalized after variable period. PLA2R staining was demonstrated in the outer glomerulus in 3 out of 13 biopsies, 2 of which were obtained from the same patient over a 5-year interval. Conclusions: PLA2R was expressed in a small number of cases diagnosed as pediatric HBV-related MN, indicating that some HBV-related MN cases may be primary MN concurrent with HBV infection.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.263-273
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• 1999

The role of phospholipase $A_2\;(PLA_2)$ in acute lung leak induced by intestinal ischemia was investigated in association with neutrophilic respiratory burst. To induce lung leak, we generated intestinal ischemia for 60 min prior to the 120 min reperfusion by clamping superior mesenteric artery in Sprague-Dawley rats. Acute lung leak was confirmed by the increased lung leak index and protein content in bronchoalveolar fluid. These changes were inhibited by mepacrine, the non-specific $PLA_2$ inhibitor. The lung myeloperoxidase (MPO) activity denoting the pulmonary recruitment of neutrophils was increased by intestinal I/R, but decreased by mepacrine. Simultaneously, the number of leukocytes in bronchoalveolar fluid was increased by intestinal ischemia/reperfusion (I/R) and decreased by mepacrine. Gamma glutamyl transferase activity, an index of oxidative stress in the lung, was increased after intestinal I/R but decreased by mepacrine, which implicates that $PLA_2$ increases oxidative stress caused by intestinal I/R. The $PLA_2$ activity was increased after intestinal I/R not only in the intestine but also in the lung. These changes were diminished by mepacrine. In the cytochemical electron microscopy to detect hydrogen peroxide, intestinal I/R increased the generation of the hydrogen peroxide in the lung as well as in the intestine. Expression of interleukin-1 (IL-1) in the lung was investigated through RT-PCR. The expression of IL-1 after intestinal I/R was enhanced, and again, the inhibition of $PLA_2$ suppressed the expression of IL-1 in the lung. Taken together, intestinal I/R seems to induce acute lung leak through the activation of $PLA_2$, the increase of IL-1 expression associated with increased oxidative stress by neutrophilic respiratory burst.

• Journal of Microbiology and Biotechnology
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• v.16 no.8
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• pp.1292-1300
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• 2006

Aeromonas encheleia, a potential human intestinal pathogen, was shown to infect a human intestinal epithelial cell line (Caco-2) in a noninvasive manner. The transcriptional profile of the Caco-2 cells after infection with the bacteria revealed an upregulated expression of genes involved in chloride secretion, including that of phospholipase A2 (PLA2) and platelet-activating factor (PAF) acetylhydrolase (PAFAH2). This was also confirmed by a real-time RT-PCR analysis. As expected from PLA2 induction, PAF was produced when the Caco-2 cells were infected with the bacteria, and PAF was also produced when the cells were treated with a bacterial culture supernatant including bacterial extracellular proteins, yet lacking lipopolysaccharides. Bacterial aerolysin was shown to induce the production of PAF.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.102.1-102.1
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• 2003

Phospholipase A$_2$(PLA$_2$) catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid(AA), a precursor of eicosanoids including prostaglandins(PGs) and leukotrienes (LTs). The same reaction also produces lyso-phospholipids. So far, at least 19 enzymes that possess PLA2 activity have been identified, consists of low-molecular-weight, Ca$\^$2+/-requiring, secretory enzymes that have been implicated in a number of biological processes, such as modification of eicosanoid generation, inflammation, host defense, and atherosclerosis. (omitted)

• Journal of Pharmacopuncture
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• v.5 no.2
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• pp.40-51
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• 2002

Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide-induced expression phospholipase $A_2$, cyclooxygenase-2 and inducible nitrogen oxide synthase, and the generation of arachidonic acid, prostaglandin D2 and E2 in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase $A_2$, cyclooxygenase and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was assayed by ELISA method in RAW 264.7 cells. The non-toxic concentrations (0.1 to $5\;{\mu}g/ml$) of bee venom determined by MTT assay, were used in this study. Results : 1. Bee venom inhibited lipopolysaccharide-induced expression of phospholipase $A_2$ in a dose dependent manner after 48 hours treatment. 2. Bee venom inhibited lipopolysaccharide-induced expression of cyclooxygenase-2 in a dose dependent manner after 24 and 48 hours treatment. 3. Bee venom inhibited lipopolysaccharide-induced expression of inducible nitrogen oxidesynthase in a dose dependent manner after 48 hours treatment. 4. The generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was not much affected by the treatment of bee venom on the lipopolysaccharide-induced generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ in RAW 264.7 cells.