• 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.

• BMB Reports
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• v.41 no.5
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• pp.369-375
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• 2008

Polygonatum cyrtonema Lectin (PCL), which is classified as a monocot mannose-binding lectin, has received great regards for its uniquely biological activities and potentially medical applications in cancer cells. This paper was initially aimed to study apoptosis of PCL on Hela cells. Thus, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) method was carried out. Through observation of cell morphologic changes and Lactate dehydrogenase (LDH) activity-based cytotoxicity assays, PCL induced HeLa cell apoptosis in a dose-dependent manner. To further gain structural basis, multiple alignments, homology modeling and docking experiments were performed to analyze the correlation between its biological activities and mannose-binding sites. Eventually, considering docking data, chemical modification properties on the three mannose-binding sites were analyzed by a series of biological experiments (e.g., hemagglutinating and mitogenic activity assays, fluorescence and Circular Dichrosim (CD) spectroscopy) to profoundly identify the role of some key amino acids in the structure-function relationship of PCL.

• Molecules and Cells
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• v.28 no.1
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• pp.67-71
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• 2009

Estrogen receptor ${\alpha}$ ($ER{\alpha}$) mediates the mitogenic effects of estrogen. $ER{\alpha}$ signaling regulates the normal growth and differentiation of mammary tissue, but uncontrolled $ER{\alpha}$ activation increases the risk to breast cancer. Estrogen binding induces ligand-dependent $ER{\alpha}$ activation, thereby facilitating $ER{\alpha}$ dimerization, promoter binding and coactivator recruitment. $ER{\alpha}$ can also be activated in a ligand-independent manner by many signaling pathways, including protein kinase A (PKA) signaling. However, in several $ER{\alpha}$-positive breast cancer cells, PKA inhibits estrogen-dependent cell growth. FoxH1 represses the transcriptional activities of estrogen receptors and androgen receptors (AR). Interestingly, FoxH1 has been found to inhibit the PKA-induced and ligand-induced activation of AR. In the present study, we examined the effects of PKA activation on the ability of FoxH1 to represses $ER{\alpha}$ transcriptional activity. We found that PKA increases the protein stability of FoxH1, and that FoxH1 inhibits PKA-induced and estradiol-induced activation of an estrogen response element (ERE). Furthermore, in MCF7 cells, FoxH1 knockdown increased the PKA-induced and estradiol-induced activation of the ERE. These results suggest that PKA can negatively regulate $ER{\alpha}$, at least in part, through FoxH1.

• Biomolecules & Therapeutics
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• v.16 no.4
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• pp.351-355
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• 2008

Prodigiosin was isolated from marine bacteria Hahella chejuensis which has been recently discovered from Marado, Cheju Island, Republic of Korea. Immunosuppressive properties have been reported for prodigiosin members such as undecylprodigiosin, metacycloprodigiosin, prodigiosin, and its synthetic analogue PNU156804 (PNU). However, the effect of this agent on the function of macrophage and splenocyte has not been characterized in detail. In the present study, we examined the effects of prodigiosin for its ability to alter the function of murine macrophage and NK cell, and the proliferation of splenocytes. When thioglycollate-elicited macrophages pre-exposed to prodigiosin (1-50 ng/ml) were stimulated with LPS/IFN-$\gamma$, pretreatment with prodigiosin resulted in the inhibition of tumoricidal activity of macrophage in a concentration-dependent manner. Tumoricidal activity of NK cell was also inhibited by prodigiosin. Moreover, we found that prodigiosin was able to cause a dose-dependent inhibition of murine lymphocyte responsiveness to Con A and LPS although T-mitogenic response was the more sensitive one. Taken together, the present results point out that prodigiosin has a suppressive effect on the mitogen-induced proliferation of murine lymphocytes and the function of macrophage and NK cell.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.126-132
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• 1998

In the present study, we examined effects of ginseng saponins (ginsenosides) on pp60c-src protein tyrosine kinase (PTK) activity, intracellular calcium concentration ([$Ca^{2+}$]i), and cell proliferation in NIH3T3 cells. Eight different ginsenosides [ginsenoside-Rb1 (G-$Rb_1$), -$Rb_2$, -Rc, -Rd, -Re, -Rf, -$Rg_1$, -$Rg_2$) and ginseng total saponin (GTS) were used for these experiments. All ginsenosides and GTS tested stimulated the activation of $pp60^{c-src}$ kinase, and especially G-$Rb_1$,-Rd,-$Rg_1$, and -$Rg_1$ showed a higher stimulatory effect than others at 16.7 $\mu\textrm{g}$/ml of ginsenosides with a 18 hr-incubation, increasing the activity by 4.5, 3.5, 3.5, and 3.0-fold, respectively, over that of untreated control. In addition, both G-Rd and -$Rg_2$)Rg2 increased ($Ca^{2+}$), to 202 and 334 nM, respectively, about 2-3-fold above the basal level within 7min at 250 $\mu\textrm{g}$/yml of ginsenosides. The increases of ($Ca^{2+}$), were eliminated by Pretreatment of EGTA, an extracellular calcium chelator, suggtasting that they result from an influx of calcium ion from extracellular medium rather than an efflux from intracellular calcium store, endoplasmic reticulum (ER). All ginsenosides studied enhanced cell proliferation to 1.2-1.4-fold over that of untreated control at 5~250 $\mu\textrm{g}$/ml of concentrations. Interestingly the promotion of cell proliferation by ginsenosides corresponded with the activation of c-src kinase, which is an early step in the mitogenic signaling cascade. Taken together, we suggest that some ginsenosides may lead to cellProliferation via the activation of cellular signal transduction Pathway involving $pp60^{c-src}$ kinase.

• Biomedical Science Letters
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• v.29 no.4
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• pp.211-219
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• 2023

Caffeic acid phenethyl ester (CAPE) is an active component of propolis obtained from honeybee hives. CAPE possesses anti-mitogenic, anti-carcinogenic, anti-inflammatory, and immunomodulatory activities in diverse systems, which know as displays antioxidant activity and inhibits lipoxygenase activities, protein tyrosine kinase, and nuclear factor kappa B (NF-κB) activation. This study aimed to investigate the effect of CAPE on lipopolysaccharide (LPS)-induced human neutrophil phagocytosis. Human neutrophils were cultured with various concentrations of CAPE (1, 10, and 100 µM) with or without LPS. The pro-inflammatory proteins (tumor necrosis factor-alpha [TNF-α], interleukin [IL]-6 and IL-8) levels were measured after 4 h incubation. To investigate the intracellular signaling pathway, we measured the levels of mitogen-activated protein kinases (MAPK), including phosphorylation of p38, extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Next, to evaluate the potential phagocytosis, neutrophils were labeled with iron particles of superparamagnetic iron oxide nanoparticles (SPIONs, 40 nm) for 1 h in culture medium containing 5 mg/mL of iron. The labeling efficiency was determined by Prussian blue staining for intracellular iron and 3T-wighted magnetic resonance imaging. CAPE decreased the activation of intracellular signaling pathways, including ERK1/2 and c-Jun, and expression of pro-inflammatory cytokines, including TNF-α and IL-6, but had no effect on the signaling pathways of p38 and cytokine IL-8. Furthermore, images obtained after mannan-coated SPION treatment suggested that CAPE induced significantly higher signal intensities than the control or LPS group. Together, these results suggest that CAPE regulates LPS-mediated activation of human neutrophils to reduce phagocytosis.

• Journal of Life Science
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• v.13 no.5
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• pp.551-558
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• 2003

Hepatitis C Virus (HCV) is associated with a severe liver disease and increased frequency in the development of hepatocellular carcinoma. Overexpression of HCV core protein is known to transform fibroblast cells. Phospholipase D (PLD) activity is commonly elevated in response to mitogenic signals, and PLD has been also reported to be overexpressed and hyperactivated in some human cancer. The aim of this study was to understand how PLD can be regulated in HCV core protein-transformed NIH3T3 mouse fibroblast cells. We observed that in unstimulated state, basal PLD activity was higher in NIH3T3 cells overexpressing HCV core protein than in vector-transfected cells. Although expression of PLD and protein kinase C (PKC) in core protein-transformed cells was similar with that of control cells, phorbol 12-myristate 13-acetate (PMA), which is known to activate PKC, stimulated significantly PLD activity in core protein-transformed cells, compared with that of the control cells. PLD activity assay using PKC isozyme-specific inhibitor, and PKC translocation experiment showed that PKC-$\delta$ was mainly involved in the PMA-induced PLD activation in the core-transformed cells. Taken together, these results suggest that PLD might be implicated in core protein-induced transformation.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.29 no.3
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• pp.134-149
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• 2016

Objectives : Gal-Geun-Tang (GT) has been described from SANGHAN in Korean traditional medicine and known to act against cold, fever, hypertension, and nasal catarrh. However, little has yet been learned about the effect of GT on immune function. In the current study, in vitro and in vivo immunomodulatory activity of GT (water extract) was investigated.Methods : Water extract of GT induced in vitro proliferation of spleen cells and significantly increased their proliferative responses during anti-CD3 activation. Using purified splenic T and B cells, it was revealed that GT has a mitogenic activity to B cells and promotes their proliferation induced by lipopolysaccharide, whereas T cell proliferation was not triggered and GT was rather inhibitory to T cell activation caused by anti-CD3 antibody. In the presence of antigen presenting cells (APC), GT addition resulted in a significant increase of IFNγ and IL-4, but not IL-2, production. However, addition of high concentration (1,000㎍/㎖) of GT led to a marked reduction in T cell cytokine production and under such condition, GT facilitated apoptosis of T cells when examined by flow cytometry with propidium iodide staining.Results : In vivo immunomdulation of GT was also investigated using a mouse model. Following keyhole limpet hemocyanin (KLH) immunization, GT (1 ㎎/day) was orally administered for 9 days. Cell numbers in thymus, spleen and peripheral blood were not altered by GT administration, indicating that such dose is not immunotoxic. Cell numbers in draining lymph nodes (LN) and ex vivo Ag-specific proliferation of LN cells were significantly elevated by GT administration. However, any preferential stimulation of T or B and CD4⁺ or CD8⁺ T cell subpopulations was not observed in a flow cytometric analysis of LN cells. This result shows that GT does not promote in vivo B cell proliferation while GT enhances Ag-specific proliferation of LN cells, unlike what was observed in vitro.Conclusions : For a further understanding of in vivo immunomodulatory activity of GT, ex vivo cytokine production of LN cells obtained from KLH-immunized mice was evaluated. Ag-specific IFNγ production was significantly higher in GT-treated mice when compared to PBS-treated control mice. In contrast, IL-4 production in GT-treated group was comparable to control group unlike to in vitro data. In addition, GT administration did not result in any significant differences in serum levels of Ig (IgM, IgG1 and IgG2a) between GT-treated and control groups. Taken together, these data strongly support that GT promotes immune response, more profoundly type 1 helper T cell (Th1) activity and GT may be applicable for treatment of intracellular parasite infection such as viral diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.547-551
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• 2013

We recently reported a Philyra pisum lectin (PPL) that exerts mitogenic effects on human lymphocytes, and its molecular characterization. The present study provides a more detailed characterization of PPL based on the results from a monosaccharide analysis indicating that PPL is a glycoprotein, and circular dichroism spectra revealing its estimated ${\alpha}$-helix, ${\beta}$-sheet, ${\beta}$-turn, and random coil contents to be 14.0%, 39.6%, 15.8%, and 30.6%, respectively. These contents are quite similar to those of deglycosylated PPL, indicating that glycans do not affect its intact structure. The binding properties to different pathogen-associated molecular patterns were investigated with hemagglutination inhibition assays using lipoteichoic acid from Gram-positive bacteria, lipopolysaccharide from Gram-negative bacteria, and both mannan and ${\beta}$-1,3-glucan from fungi. PPL binds to lipoteichoic acids and mannan, but not to lipopolysaccharides or ${\beta}$-1,3-glucan. PPL exerted no significant antiproliferative effects against human breast or bladder cancer cells. These results indicate that PPL is a glycoprotein with a lipoteichoic acid or mannan-binding specificity and which contains low and high proportions of ${\alpha}$-helix and ${\beta}$-structures, respectively. These properties are inherent to the innate immune system of P. pisum and indicate that PPL could be involved in signal transmission into Gram-positive bacteria or fungi.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.1
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• pp.106-115
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• 2010

Phosphorylated dextran (P-Dex) is an acidic polysaccharide that functions as an immune adjuvant. P-Dex is known to regulate immune response by maintaining a balance between Th1 and Th2 cells in vitro, and thus may also be important in the control of allergic reactions. In the current study, we report the optimum conditions required for the efficient phosphorylation of dextran without toxicity. We found that when dextran was heated at 160${^{\circ}C}$ for 24 h in phosphate buffer (pH 5.0), the resulting P-Dex demonstrated the highest phosphorus content (6.8%). We also report that P-Dex enhances mitogenic activity in mouse splenocytes and induces expression of CD69 and CD86 on the surface of B cells and dendritic cells (DC) in vitro. Oral administration of P-Dex to ovalubmin (OVA)-immunized mice was found to reduce antigen-induced cell proliferation and suppress the expression of CD86 on Th2-inducing DC via exogenous OVA stimulation. P-Dex was also found to increase IL-10 expression in the splenocytes of treated mice. These findings suggest that oral administration of P-Dex increases immunological tolerance and improves the specificity of immunological response to specific antigens.