• Development and Reproduction
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• v.4 no.2
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• pp.237-242
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• 2000

Growth hormone releasing hormone (GHRH), the major hypothalamic stimulus of GH secretion from the anterior pituitary gland, has been found to be present in several extrahypothalamic sites including placenta testis, ovary and anterior pituitary gland. The present study was performed to elucidate the role of pituitary GHRH on proliferation of cells derived from rat anterior pituitary gland. The GHRH content of pituitary tissue, cultured pituitary cells, and the conditioned media was evaluated by radioimmunoassay (RIA). Primary cultures of pituitary cells derived from adult rats were prepared by enzymatic dispersion. Significant amounts of GHRH-like molecules were detected in both pituitary tissue and cell cultures by GHRH RIA. Competition curves with increasing amounts of tissue extracts and conditioned media were parallel with those of standard peptide, indicating that the pituitary GHRH-like material is similar to authentic GHRH. To analyze specific cell types responsible for producing GHRH in anteroior pituitary, cell fractionation technique combined with GHRH RIA was performed. In cell fractionation experiment, the highest level of GHRH content was found in gonadotrope enriched-fraction and followed by somatotrope-, lactotrope- and thyrotrope-fraction. Treatment of pituitary cells with GHRH resulted in a dose-dependent increase in [$^3$H] thymidine incorporation. The mitogenic effect of GHRH could be mediated by typical oncogenic activation since the GHRH induced transient increase in c-fos mRNA levels with peak response at 30 minutes. The present study demonstrated that i) the pituitary GHRH expressed in the rat anterior pituitary gland can be secreted, ii) among the various cell types, gonadotropes and somatotorpes are the major GHRH source, and iii) the GHRH treatment increased the [$^3$H] thymidine incorporation and c-fos transcriptional activity in the pituitary cell culture. These findings suggested that GHRH could participated in the paracrine and/or autocrine regulation of cell proliferation, as well as promoting growth hormone secretion.

• Molecules and Cells
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• v.22 no.1
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• pp.70-77
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• 2006

Platelets are anucleate cytoplasmic fragments derived from bone marrow megakaryocytes, and endothelial cells constitute the barrier between bloodstream and adjacent tissues. Although platelets are thought to regulate the biological functions of endothelial cells, the molecular mechanisms involved are poorly understood. With human umbilical vein endothelial cells and freshly isolated platelets, we established an in vitro model of platelet-induced endothelial cell proliferation. Platelets stimulated endothelial cell proliferation in a dose-dependent manner and transwell experiments with semi-permeable membranes suggested that direct cell-to-cell contacts were required. We developed mAbs against platelets and selected a mAb that blocks their proliferative effect. We purified the antigen by immunoprecipitation and identified it by Q-TOF MS analysis as the tetraspanin CD9. Since both platelets and endothelial cells expressed CD9 strongly on their surfaces we carried out a pre-treatment experiment that showed that CD9 molecules on the endothelial cells participate in the mitogenic effect of the platelets. The inhibitory effect of our mAb was comparable to that of a well-known functional anti-CD9 mAb. These results suggest that the tetraspanin CD9 plays an important role in endothelial regeneration.

• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.78-91
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• 1997

Peroxisome is a single membrane-bounded organelle found in hepatic parenchymal cells and kidney tubular epithelial cells. A number of enzymes exist in peroxisome contributing to anabolic and catabolic peroxisomal functions. Extramitochontriai $\beta$-oxidation of fatty acid is a major function of peroxisome. Peroxisomes can be proliferated by many structually unrelated compounds such as hypolipidemic drugs, plasticizers, pesticides, some pharmaceutical agents and high fat diet. These chemicals, called peroxisome proliferators, act via the peroxisome proliferator activated receptor, to induce peroxisome proliferation, hepatomegaly and hepatocellular carcinoma in rodent. The clear mechanisms of peroxisome proliferator-induced hepatocarcinogenesis have been not demonstrated. Since they are not genotoxic, biochemical changes or changes in gene expressions may be involved. A free radical theory has been suggested based on the finding of oxidative damages of macromolecules by hydrogen peroxide released in the peroxisomal $\beta$-oxidation of fatty acid. Increased cell proliferation by a peroxisome proliferator has been also thought to be an important factor in the hepatocarcinogenesis as suggested in other cases of nongenotoxic carcinogenesis. The alternation of eicosanoid concentrations by peroxisome proliferators may be important in the peroxisome proliferator-induced hepatocarcinogenesis since peroxisome proliferators decrease the concentration of eicosanoids, and the peroxisome proliferator ciprofibrate-eicosanoid combination is comitogenic and costimulates some mitogenic signals in hepatocytes. All of proposed mechanisms should be considered in the peroxisome prolifrator-induced hepatocarcinogenesis.

• Archives of Pharmacal Research
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• v.14 no.3
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• pp.207-216
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• 1991

Pseudixus japonicus agglutinin (PJA) was isolated. And its characteristics were compared with those of concanavalin A (Con A). PJA is a glycopritein composed of 49.3% carbohydrate and 50.7% protein which had relatively high percentages of glutamic acid, aspartic acid and phenylalanine residues. The hemagglutinating activity of PJA was approximately one-eighth of that of Con A when tested with mouse crythrocytes. PJA failed to simulate the proliferation or transformation of human and mouse lymphocytes in contratst to Con A. PJA and Con A showed cytotoxicities against SNU-1 (human stomach cancer cells), SNU-CI (human colon cancer cells) and mouse Sarcoma 180 cells when tested by 3-(4, 5-dimethyl thiazol-2-yl)2. 5-diphenyl tetrazolium bromide (MIT) colorimetric assay. The antitumor activity of the lectin in vivo was also tested in Sarcoma 180 bearing mice. There was no significant difference in prologation of lifc span of the mice after the treatment with PJA and Con A for 10 consecutive days.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1450-1455
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• 2007

Evodiae Fructus(EF) has been used as Traditional medicine for the treatment of headache, abdominal pain, hemorrhage, and menorrhae in many Asian countries. The present study was conducted to investigate the immunomodulatory effect on cyclophosphamide(CY)-induced immunesuppression of water extracted EF(EFE). In the mouse spleen cell proliferation assay, EFE enhanced mitogenic activity and restored the CY-induced cell suppression. In the nitric oxide(NO) assay, EFE inhibited NO production and iNOS protein levels in LPS-stimulated RAW 264.7 cells. In the GC-MS analysis, many ingredients of EFE were detected by solvents. These results indicated that EFE can modulate immune response through immune cell proliferation, the regulation of NO production and the inhibition of CY-induced immunotoxicity.

• BMB Reports
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• v.49 no.7
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• pp.357-358
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• 2016

Merlin, encoded by the NF2 gene, is a tumor suppressor that exerts its function via inhibiting mitogenic receptors at the plasma membrane. Although multiple mutations in Merlin have been identified in Neurofibromatosis type II (NF2) disease, its molecular mechanism is not fully understood. Here, we show that Merlin interacts with LRP6 and inhibits LRP6 phosphorylation, a critical step for the initiation of Wnt signaling. We found that treatment of Wnt3a caused phosphorylation of Merlin by PAK1, leading to detachment of Merlin from LRP6 and allowing the initiation of Wnt/β-catenin signaling. A higher level of β-catenin was found in tissues from NF2 patients. Enhanced proliferation and migration caused by knockdown of Merlin in glioblastoma cells were inhibited by suppression of β-catenin. Conclusively, these results suggest that sustained Wnt/β-catenin signaling activity induced by abrogation of Merlin-mediated inhibition of LRP6 phosphorylation might be a cause of NF2 disease.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.248.1-248.1
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• 2003

Keloids are characterized by abnormal proliferation of fibroblasts and overproduction of collagen. Recently, it is reported that transforming growth factor beta (TGFb) and its signaling molecule, SMAD3 are related to the mitogenic effect of fibroblasts and a stimulatory factor for collagen synthesis. Cationic SLN was developed to improve the complex formation of DNA/SLN and enhance the uptake efficiency to cells. SLN was formulated by DC-Chol, DOPE, trimyristin as a solid core and other surfactant. The physical properties of the SLN and the ATS-SLN complex were characterized. (omitted)

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.4
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• pp.896-901
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• 2006

Zingiberis rhizoma(ZB) has been used to treat a various condition and disease in traditional oriental medicine. The present study was conducted to evaluate the immunomodulatory effect of aqueous-extracted ZB(ZBE) on methotrexate (MTX)-induced immune suppression in mouse spleen cells. In spleen cell proliferation assay, ZBE enhanced mitogenic activity in mouse spleen cells. In RT-PCR, ZBE induced IL-2, IFNr and IL-6 cytokine gene expression in mouse spleen cells. In spite of MTX treatment, IL-2, IFNr and IL-6 gene expressions sustained in MTX treated spleen cells. CD45R/B220, pan B marker was slightly increased in ZBE treated mouse spleen cells. IL-6, B cell tropical cytokine, production was induced by ZBE-treated mouse spleen cells and IL-6 production was sustained on MTX-ZBE co-cultured cells. ZBE administration enhanced suNival of S-180 bearing mouse. These data indicate that ZBE has a protective effect of immune suppression caused by MTX, and ZBE may be enhance cellular and humoral function by regulate cytokine gene expression as well as the mitogenic effect on spleen cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.2
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• pp.485-490
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• 2007

Zingiberis rhizoma(ZB) has been used to treat a various condition and disease in many traditional preparation. The present study was conducted to investigate the immunomodulatory effect on cyclophosphamide(CY)-induced immunotoxicity of aqueous-extracted ZB(ZBE) using in vitro and in vivo experiment. In vitro experiment, the mouse spleen cells proliferation and nitric oxide(NO) production in RAW 264.7 mouse macrophage cells were investigated. ZBE enhanced mitogenic activity in mouse spleen cells. The suppression of CY-induced mouse speen cell proliferation was significantly restored by ZBE treatment. ZBE inhibited NO production, iNOS mRNA and protein levels in LPS-stimulated RAW 264.7 cells. In vivo experiment, ZBE was orally administrated(single dose of 150mg/kg for 12 days) and CY i.p(150mg/kg) injected to SD rats. In CY alone injected group, body weights and spleen weights, and a various hematological parameters were reduced when compared with control group, whereas those values were increased by concomitant treatment of CY and ZBE when compared with CY alone injected group. These results indicated that ZBE can modulate CY-induced immune suppression through immune cell proliferation, the regulation of NO production and the inhibition of CY-induced immunotoxicity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.2
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• pp.414-424
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• 2007

Adenophorae Radix (AR), Liriopis Tuber (LT), Dendrobii Monile (DM), Polygonati Officinalis (PO), Polygonati Rhizoma (PR) have been used to treated a variety condition/diseases in traditional oriental medicine. The present study was conducted to investigate the immunmodulatory effects of the water-extracted AR, LT, DH, PO and PR. In spleen cell proliferation assay, DH was significantly enhanced mitogenic activity compared with control group. In RT-PCR, DH ad PO induced IL-2 and IFNr cytokine gene expression in mouse spleen cells. Methotrexate(MTX), immune supression agent, was significantly inhibited mouse spleen cell proliferation(1600 mg/ml). In spite of MTX treatement, DH and PO sustained the spleen cell proliferation, In the flow cytometry analysis, DH stimulated mouse spleen cells showed an increase in B-cell phenotype (CD45R/B220). The water-extracted DH and PO inhibited NO production and iNOS expression in LPS-stimulated RAW 264.7 macrophage cell. DH induced IL-2 and IFNg gene expression in human peripheral mononuclear cells. The GC-MS analysis show that the main component of water-extracted DH was b-Nitroethyl alcohol. The main components of water-extracted PO were Dipirartril-tropico, Methyl sulfoxide and Demsodrox. These data suggest that among these extracts, DH has a protective effcet of immune suppression caused by MTX. DH may be enhance cellular and humoral immune response by the regulation of cytokine gene expression, NO production and B cell production.