• International Journal of Oral Biology
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• 제41권1호
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• pp.17-23
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• 2016

Chronic/cyclic neutropenia, leukocyte adhesion deficiency syndrome, Papillon-$Lef{\grave{e}}vre$ syndrome, and $Ch{\grave{e}}diak$-Higashi syndrome are associated with severe periodontitis, suggesting the importance of neutrophils in the maintenance of periodontal health. Various Toll-like receptor (TLR) ligands are known to stimulate neutrophil function, including FcR-mediated phagocytosis. In the present study, the effect of TLR2 activation on the non-opsonic phagocytosis of oral bacteria and concomitant production of reactive oxygen species (ROS) by human neutrophils was evaluated. Neutrophils isolated from peripheral blood were incubated with Streptococcus sanguinis or Porphyromonas gingivalis in the presence of various concentrations of $Pam_3CSK_4$, a synthetic TLR2 ligand, and analyzed for phagocytosis and ROS production by flow cytometry and chemiluminescence, respectively. $Pam_3CSK_4$ significantly increased the phagocytosis of both bacterial species in a dose-dependent manner. However, the enhancing effect was greater for S. sanguinis than for P. gingivalis. $Pam_3CSK_4$ alone induced ROS production in neutrophils and also increased concomitant ROS production induced by bacteria. Interestingly, incubation with P. gingivalis and $Pam_3CSK_4$ decreased the amounts of ROS, as compared to $Pam_3CSK_4$ alone, indicating the possibility that P. gingivalis survives within neutrophils. However, neutrophils efficiently killed phagocytosed bacteria of both species despite the absence of $Pam_3CSK_4$. Although P. gingivalis is poorly phagocytosed even by the TLR2-activated neutrophils, TLR2 activation of neutrophils may help to reduce the colonization of P. gingivalis by efficiently eliminating S. sanguinis, an early colonizer, in subgingival biofilm.

• 대한의생명과학회지
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• 제12권3호
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• pp.145-151
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• 2006

Leukotactin-l (Lkn-l )/CCL15 has been known as a potent chemoattractant of leukocytes. However, the precise function of Lkn-l in human neutrophils has not been explained well. In the present study, we investigated the contribution of Lkn-1 in chemotactic activity of human neutrophils. Both CCR1 and CCR3 mRNA expressions are strongly expressed in human neutrophils but CCR2 protein expression was uniquely detected on the cell surface. Lkn-l binding to CCR1 and CCR3 induced chemotactic activity of neutrophils. Chemotactic index of Lkn-l was comparable to that of IL-8. $MIP-1{\alpha}/CCL3$ binding to CCR1 and CCR5 has no effect on neutrophil migration. Cell migration, in response to Lkn-l, was blocked by pertussis toxin (Ptx), a $G_o/G_i$ protein inhibitor, and U73122, a phospholipase C(PLC) inhibitor but not by protein kinase C inhibitor such as rottlerin, and Ro-31-8425. Taken together, our results demonstrate that Lkn-l transduces the chemotaxis signal through $G_o/G_i$ protein and PLC. This finding provides the molecular mechanism by which Lkn-l may contribute to neutrophil movement into the site of inflammation.

• Parasites, Hosts and Diseases
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• 제42권4호
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• pp.205-208
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• 2004

Neutrophils are important effector cells against protozoan extracellular parasite Entamoeba histolytica, which causes amoebic colitis and liver abscess in human beings. Apoptotic cell death of neutrophils is an important event in the resolution of inflammation and parasite's survival in vivo. This study was undertaken to investigate the ultrastructural aspects of apoptotic cells during neutrophil death triggered by Entamoeba histolytica. Isolated human neutrophils from the peripheral blood were incubated with or without live trophozoites of E. histolytica and examined by transmission electron microscopy (TEM). Neutrophils incubated with E. histolytica were observed to show apoptotic characteristics, such as compaction of the nuclear chromatin and swelling of the nuclear envelop. In contrast, neutrophils incubated in the absence of the amoeba had many protrusions of irregular cell surfaces and heterogenous nuclear chromatin. Therefore, it is suggested that Entamoeba-induced neutrophil apoptosis contribute to prevent unwanted tissue inflammation and damage in the amoeba-invaded lesions in vivo.

• 동의생리병리학회지
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• 제20권2호
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• pp.477-481
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• 2006

A clinical report indicates that 'Geijibokryunghwan(GBH) is very effective in treating thrombosis in those patients who have difficulties with more conventional antithrombotic drugs. The isolation and identification of various compounds from this plant and the same genus have been reported by several groups. However, the pharmaceutical effect of the GBH on superoxide generation in human neutrophils has not been studied. In the present report, we investigated the possibility of using herbal medicine as an alternative therapy. In particular, we studied tremor in antiatheroscleosis. In this report, we shows the GBH extract can be used as a potential atherosclerosis preventive agent in human. The effect of GBH on stimulus-induced superoxide generation and phosphorylation of tyrosine residues of protein in human neutrophils was investigated. In a conclusion, GBH suppressed tyrosine phosphorylase in a dose-dependent manner, and may have pharmacoceutical applications. These data suggest that GBH extracts merits investigation as a potential anti-atherosclerogenic agent in humans.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.415-420
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• 2011

The experimental manipulation of protooncogenes and their gene products is a valuable research tool for the study of human neoplasia. In this study, the recently identified human cervical cancer protooncogene (HccR-2) was expressed in transgenic mice under the control of the tetracycline regulatory system. Mice expressing the HccR-2 transgene showed an altered myeloid development characterized by an increased percentage of mature and band-form neutrophils in the peripheral blood, liver and spleen. This phenotype is similar to human chronic neutrophilic leukemia (CNL) in many ways, which is a rare chronic myeloproliferative disorder (CMD) that presents as a sustained leukocytosis of mature neutrophils with a few or no circulating immature granulocytes, an absence of peripheral blood monocytosis, basophilia, or eosinophilia, and an infiltration of neutrophils into the liver, spleen and kidney. Thus, the HccR-2 transgenic mouse model is imperative not only for investigating the biological properties of the HccR-2 protooncogene in vivo, but also for analyzing the mechanisms involved in the progression of CNL.

• BMB Reports
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• 제35권5호
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• pp.482-487
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• 2002

Early activation of human peripheral blood polymorphonuclear neutrophils is characterized by their morphological changes from spherical to polarized shapes. The endotoxins from enteric pathogens (S. dysenteriae type 1, V. cholerae Inaba 569B, S. typhimurium, and K. pneumoniae) were assessed by their ability to induce morphological polarization of the neutrophils as measures of early activation. Phagocytic activity, adhesion, chemokinetic locomotion, and nitroblue tetrazolium (NBT) dye-reduction ability measured the later activation of the cells. Neutrophils showed distinct morphological polarization in suspension over a wide range of concentrations of these endotoxins when were compared with those that were induced by the standard chemotactic factor, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It was discovered that all of the endotoxins induced locomotor responses in neutrophils in suspension that were dose- and time-dependent. The optimum concentration for the endotoxins of S. dysenteriae, V. cholerae, and K. pneumoniae was 1 mg/ml in which 71, 69, and 66% of the neutrophils were polarized. However, the S. typhimurium dose was 2 mg/ml in which 50% of the cells responded. Neutrophils that were stimulated with endotoxins also showed increased random locomotion (p<0.005) through cellulose nitrate filters, but an enhanced adhesion of the cells to glass surfaces (p<0.03). These are important functions of these cells to reach and phagocytose damaged cells, as well as invading microorganisms. Interestingly, the endotoxins had a highly-significant inhibitory effect upon the proportions of neutrophils phagocytosing opsonized yeast (p<0.01) with a small number of yeast that were engulfed by the cells (p<0.02). Further, endotoxin-treated cells showed an enhanced ability to reduce NBT dye (p<0.03). Therefore, we concluded that endotoxins of enteric pathogens are neutrophil chemotactic factors.

• Parasites, Hosts and Diseases
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• 제48권4호
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• pp.285-290
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• 2010

Tyrosine kinases are one of the most important regulators for intracellular signal transduction related to inflammatory responses. However, there are no reports describing the effects of tyrosine kinases on neutrophil apoptosis induced by Entamoeba histolytica, In this study, isolated human neutrophils from peripheral blood were incubated with live trophozoites in the presence or absence of tyrosine kinase inhibitors. Entamoeba-induced receptor shedding of CD16 and PS externalization in neutrophils were inhibited by pre-incubation of neutrophils with the broad-spectrum tyrosine kinase inhibitor genistein or the Src family kinase inhibitor PP2. Entamoeba-induced ROS production was also inhibited by genistein or PP2, Moreover, genistein and PP2 blocked the phosphorylation of ERK and p38 MAPK in neutrophils induced by E. histolytica. These results suggest that Src tyrosine kinases may participate in the signaling event for ROS-dependent activation of MAPKs during neutrophil apoptosis induced by E. histolytica.

• BMB Reports
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• 제38권3호
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• pp.343-349
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• 2005

Gamma-glutamyltransferase (GGT, EC 2.3.2.2) which hydrolyzes glutathione (GSH), is required for the maintenance of normal intracellular GSH concentration. GGT is a membrane enzyme present in leukocytes and platelets. Its activity has also been observed in human neutrophils. In this study, GGT was purified from Triton X-100 solubilized neutrophils and its kinetic parameters were determined. For kinetic analyses of transpeptidation reaction, $\gamma$-glutamyl p-nitroanilide was used as the substrate and glycylglycine as the acceptor. Apparent $K_m$ values were determined as 1.8 mM for $\gamma$-glutamyl p-nitroanilide and 16.9 mM for glycylglycine. The optimum pH of GGT activity was 8.2 and the optimum temperature was $37^{\circ}C$. It had thermal stability with 58% relative activity at $56^{\circ}C$ for 30 min incubation. L-serine, in the presence of borate, was detected as the competetive inhibitor. Bromcresol green inhibited neutrophil GGT activity as a noncompetetive inhibitor. The neutrophils seem to contain only the isoenzyme that is present in platelets. We characterized the kinetic properties and compared the type of the isoenzyme of neutrophil GGT with platelet GGT via polyacrylamide gel electrophoresis (PAGE) under a standart set of conditions.

• 생명과학회지
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• 제17권7호통권87호
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• pp.948-955
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• 2007

생체 면역반응에 중요한 역할을 하는 호중구의 세포사멸은 자연적으로 일어나거나 여러 외부자극에 의한 신호의 전달에 의해 증가하거나 지연된다. 또한 사이토카인과 같은 분화제에 의해 세포사멸이 지연되고 항원 제시 기능을 가진 수지상 세포로 분화되기도 한다. 본 연구에서는 세포사멸 억제제와 사이토카인을 이용한 시스템에서 호중구가 수지상 세포로 분화되는가를 조사하였다. Pancaspase와 serine protease의 억제제인 zVAD-fmk와 AEBSF를 처리하였을 때 호중구의 세포사멸은 현저히 감소되며 AEBSF는 caspase-3와 serine protease활성을 모두 억제하였다. 호중구의 세포사멸을 효과적으로 억제하는 AEBSF와 함께 분화제로 널리 쓰이는 CM-CSF를 같이 처리하여 3일 동안 배양하면 수지상 세포에서 높이 발현되는 CD8O, CD83 및 MHC class ll의 세포표면 마커의 발현이 증가하였다. AEBSF와 CM-CSF를 처리한 호중구를 T-세포와 함께 배양하였을 때 SEB가 존재할 경우 T-세포가 증식되었으며 SEB가 없이도 $IFN{\gamma}$는 생성되었다. 이들 결과들로 부터 serine protease 억제제인 AEBSF를 호중구에 처리하여 세포사멸을 효과적으로 억제하는 것과 수지상 세포로의 분화를 촉진하는 사이토카인인 CM-CSF의작용을 나타내게 하는 조건과는 서로 상호적으로 연관되어 작용할 수 있다는 것을 제시하고 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권1호
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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.