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The Transcription Factor Mist1 Regulates the Cellular Polarity in Mouse Pancreatic Acinar Cells.

Yu Mi YANG ; Syng Ill LEE ; Dong Min SHIN

International Journal of Oral Biology.2012;37(1):37-41.

Pancreatic acinar cells exhibit a polarity that is characterized by the localization of secretory granules at the apical membrane. However, the factors that regulate cellular polarity in these cells are not well understood. In this study, we investigated the effect of Mist1, a basic helix-loop-helix transcription factor, on the cellular architecture of pancreatic acinar cells. Mist1-null mice displayed secretory granules that were diffuse throughout the pancreatic acinar cells, from the apical to basolateral membranes, whereas Mist1 heterozygote mice showed apical localization of secretory granules. Deletion of the Mist1 gene decreased the expression of type 3 inositol 1,4,5-triphosphate receptors (IP3R) but did not affect apical localization and expression of IP3R2. Mist1-null mice also displayed an increase in luminal areas and an increase in the expression of zymogen granules in pancreatic acinar cells. These results suggest that Mist1 plays a critical role in polar localization of cellular organelles and in maintaining cellular architecture in mouse pancreatic acinar cells.
Acinar Cells ; Animals ; Cell Polarity ; Heterozygote ; Inositol 1,4,5-Trisphosphate Receptors ; Membranes ; Mice ; Organelles ; Phenobarbital ; Secretory Vesicles ; Transcription Factors

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Dlx3 and Dlx5 Inhibit Adipogenic Differentiation of Human Dental Pulp Stem Cells.

Hye Lim LEE ; Hyun NAM ; Gene LEE ; Jeong Hwa BAEK

International Journal of Oral Biology.2012;37(1):31-36.

Dlx3 and Dlx5 are homeobox domain proteins and are well-known regulators of osteoblastic differentiation. Since possible reciprocal relationships between osteogenic and adipogenic differentiation in mesenchymal stem cells exist, we examined the regulatory role of Dlx3 and Dlx5 on adipogenic differentiation using human dental pulp stem cells. Over-expression of Dlx3 and Dlx5 stimulated osteogenic differentiation but inhibited adipogenic differentiation of human dental pulp stem cells. Dlx3 and Dlx5 suppressed the expression of adipogenic marker genes such as C/EBPalpha, PPARgamma, aP2 and lipoprotein lipase. Adipogenic stimuli suppressed the mRNA levels of Dlx3 and Dlx5, whereas osteogenic stimuli enhanced the expression of Dlx3 and Dlx5 in 3T3-L1 preadipocytes. These results suggest that Dlx3 and Dlx5 exert a stimulatory effect on osteogenic differentiation of stem cells through the inhibition of adipogenic differentiation as well as direct stimulation.
Dental Pulp ; Durapatite ; Genes, Homeobox ; Humans ; Lipoprotein Lipase ; Mesenchymal Stromal Cells ; Osteoblasts ; PPAR gamma ; Proteins ; RNA, Messenger ; Stem Cells

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Localization of the Mental and Infraorbital Foramen with related to the Soft-tissue Landmarks.

Yun Ho LEE ; Myoung Hwa LEE ; Sun Kyoung YU ; GooSoo JEONG ; Do Kyung KIM ; Heung Joong KIM

International Journal of Oral Biology.2012;37(1):25-29.

During maxillofacial surgery, the infraorbital and mental nerves are blocked at eac foramen to induce local anesthesia. This study examined the relative locations of the infraorbital foramen (IOF) and mental foramen (MF) based on soft-tissue landmarks. Twenty-eight hemifacial cadavers were dissected to expose the IOF and MF. The distances between the bilateral IOFs, the bilateral MFs, the alae of the nose (alares), and the corners of the mouth (cheilions) were measured directly on cadavers by using a digital vernier caliper. The vertical and horizontal distances of the IOF and MF relative to the alare and cheilion were measured indirectly on digital photographs using Adobe Photoshop (Adobe, CA, USA). The distance between the bilateral IOFs (58.09 +/- 4.04 mm) was longer than the distance between the bilateral MFs (50.32 +/- 1.93 mm). The distances between the bilateral alares and cheilions were 41.22 +/- 3.44 mm and 58.43 +/- 6.62 mm, respectively. The IOF was located 12.92 +/- 3.75 mm superior and 7.88 +/- 2.56 mm lateral to the alare, and the vertical angle (Angle 1) between these structures was 31.67 +/- 13.36degrees superolaterally. The MF was located 21.83 +/- 3.26 mm inferior and 5.56 +/- 3.37 mm medial to the cheilion, and the vertical angle (Angle 2) between these structures was 14.05 +/- 10.12degrees inferomedially. In conclusion, these results provide more detailed information about the locations of the IOF and MF relative to soft-tissue landmarks.
Aminocaproic Acids ; Anesthesia, Local ; Cadaver ; Mouth ; Nose ; Surgery, Oral

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Effects of Mitochondrial Reactive Oxygen Species on Neuronal Excitability in Rat Spinal Substantia Gelatinosa Neurons.

Hae In LEE ; A Reum PARK ; Sang Woo CHUN

International Journal of Oral Biology.2012;37(1):17-23.

Recent studies indicate that reactive oxygen species (ROS) are critically involved in persistent pain primarily through spinal mechanisms, and that mitochondria are the main source of ROS in the spinal dorsal horn. To investigate whether mitochondrial ROS can induce changes in membrane excitability on spinal substantia gelatonosa (SG) neurons, we examined the effects of mitochondrial electron transport complex (ETC) substrates and inhibitors on the membrane potential of SG neurons in spinal slices. Application of ETC inhibitors, rotenone or antimycin A, resulted in a slowly developing and slight membrane depolarization in SG neurons. Also, application of both malate, a complex I substrate, and succinate, a complex II substrate, caused reversible membrane depolarization and enhanced firing activity. Changes in membrane potential after malate exposure were more prominent than succinate exposure. When slices were pretreated with ROS scavengers such as phenyl-N-tert-buthylnitrone (PBN), catalase and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL), malate-induced depolarization was significantly decreased. Intracellular calcium above 100 microM increased malateinduced depolarization, witch was suppressed by cyclosporin A, a mitochondrial permeability transition (MPT) inhibitor. These results suggest that enhanced production of spinal mitochondrial ROS can induce nociception through central sensitization.
Animals ; Antimycin A ; Calcium ; Catalase ; Central Nervous System Sensitization ; Cyclosporine ; Electron Transport ; Fires ; Horns ; Malates ; Membrane Potentials ; Membranes ; Mitochondria ; Neurons ; Nociception ; Permeability ; Rats ; Reactive Oxygen Species ; Rotenone ; Substantia Gelatinosa ; Succinic Acid

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Surface Characteristics and Biocompatibility of Titanium Coated with Dentin-derived Hydroxyapatite.

Hae Jin KIM ; Mee Kyung SON ; Kyung Ku LEE ; Bo Ah LEE ; Young Joon KIM

International Journal of Oral Biology.2012;37(1):9-16.

The aim of this study was to evaluate surface characteristics and biological properties of the dentin-derived hydroxyapatite (HA) coating on titanium substrate. Dentin-derived HA was obtained from extracted human teeth using a calcination method at 850degrees C. The commercially pure titanium (cp-Ti, ASTM Grade II) was used as a metallic substrate and a radio frequency magnetron sputtering method was employed as a coating method. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were utilized to investigate the coating aspects and composition. Atomic forced microscopy (AFM) and a surface profiler were used to assess the surface morphology and roughness. Corrosion tests were performed in phosphate-buffered saline at a 36.5 +/- 1degrees C in order to determine the corrosion behavior of the uncoated and coated specimens. The biocompatibility of dentin-derived HA coated specimens with fetal rat calvarial cells and human gingival fibroblasts was assessed by SEM and cell proliferation analysis. The results showed that the dentin-derived HA coatings appeared to cover thinly and homogeneously the surfaces without changing of the titanium substrate. The EDX analysis of this the coating surface indicated the presence of Ca and P elements. The mean surface roughness of cp-Ti and dentin-derived coating specimens was 0.27 microm and, 1.7 microm, respectively. Corrosion tests indicated a stable passive film of the dentin-derived HA coating specimens. SEM observations of fetal rat calvarial cells and human fibroblast cells on coated surfaces showed that the cells proliferated and developed a network of dense interconnections. The cells on all specimens proliferated actively within the culture period, showing good cell viability. At day 1 and 3, dentin-derived coating specimens showed 89% and 93% cell viability, respectively, when normalized to cp-Ti specimens. These results suggest that dentin-derived HA coating using the RF magnetron sputtering method has good surface characteristics and biocompatibility.
Animals ; Cell Proliferation ; Cell Survival ; Corrosion ; Durapatite ; Fibroblasts ; Humans ; Microscopy ; Microscopy, Electron, Scanning ; Rats ; Titanium ; Tooth

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Effects of Whole Body Irradiation on Morphine, DAMGO, DPDPE, U50,488H and beta-endorphin-Induced Antinociception.

Tae Won PARK ; Jin Kyu KIM ; Jae Soo JEONG ; Tae Wan KIM ; Young Kyung CHO ; Kyung Nyun KIM ; Ki Myung CHUNG

International Journal of Oral Biology.2012;37(1):1-7.

Opioid receptors have been pharmacologically classified as micro, delta, kappa and epsilon. We have recently reported that the antinociceptive effect of morphine (a micro-opioid receptor agonist), but not that of beta-endorphin (a novel micro/epsilon-opioid receptor agonist), is attenuated by whole body irradiation (WBI). It is unclear at present whether WBI has differential effects on the antinociceptive effects of micro-, delta-, kappa- and epsilon-opioid receptor agonists. In our current experiments, male ICR mice were exposed to WBI (5Gy) from a 60Co gamma-source and the antinociceptive effects of opioid receptor agonists were assessed two hours later using the hot water (52degrees C) tail-immersion test. Morphine and D-Ala2,N-Me-Phe4,Gly-olenkephalin(DAMGO), [D-Pen2-D-Pen5]enkephalin (DPDPE), trans-3,4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamide (U50,488H), and beta-endorphin were tested as agonists for micro, delta, kappa, and epsilon-opioid receptors, respectively. WBI significantly attenuated the antinociceptive effects of morphine and DAMGO, but increased those of beta-endorphin. The antinociceptive effects of DPDPE and U50,488H were not affected by WBI. In addition, to more preciously understand the differential effects of WBI on micro- and epsilon-opioid receptor agonists, we assessed pretreatment effects of beta-funaltrexamine (beta-FNA, a micro-opioid receptor antagonist) or beta-endorphin1-27 (beta-EP1-27, an epsilon-opioid receptor antagonist), and found that pretreatment with beta-FNA significantly attenuated the antinociceptive effects of morphine and beta-endorphin by WBI. beta-EP1-27 significantly reversed the attenuation of morphine by WBI and significantly attenuated the increased effects of beta-endorphin by WBI. The results demonstrate differential sensitivities of opioid receptors to WBI, especially for micro- and epsilon-opioid receptors.
3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer ; Animals ; beta-Endorphin ; Enkephalin, Ala(2)-MePhe(4)-Gly(5)- ; Enkephalin, D-Penicillamine (2,5)- ; Humans ; Male ; Mice ; Mice, Inbred ICR ; Morphine ; Naltrexone ; Receptors, Opioid ; Water ; Whole-Body Irradiation

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Staurosporine Induces ROS-Mediated Process Formation in Human Gingival Fibroblasts and Rat Cortical Astrocytes.

Han Gil LEE ; Du Sik KIM ; Seong Ah MOON ; Jeong Wan KANG ; Jeong Taeg SEO

International Journal of Oral Biology.2015;40(1):27-33. doi:10.11620/IJOB.2015.40.1.027

In the present study, we investigated the effect of staurosporine on the formation of cellular processes in human gingival fibroblasts and rat astrocytes. Staurosporine caused a rapid induction of process formation in human gingival fibroblasts and rat astrocytes in a concentration dependent manner. The process formation of human gingival fibroblasts and rat astrocytes was prevented by the pretreatment with N-acetylcysteine, suggesting that staurosporine-induced ROS production was responsible for the process formation. Colchicine, a microtubule depolymerizing agent, inhibited the staurosporine-induced process formation, whereas cytochalasin D, an actin filament breakdown agent, failed to suppress the formation of cellular processes. This result indicated that polymerization of microtubule, and not actin filament, was responsible for the formation of cellular processes induced by staurosporine. In support of this hypothesis, Western blot analysis was conducted using anti-tubulin antibody, and the results showed that the amount of polymerized microtubule was increased by the treatment with staurosporine while that of depolymerized beta-tubulin in soluble fraction was decreased. These results indicate that staurosporine induces ROS-mediated, microtubule-dependent formation of cellular processes in human gingival fibroblasts and rat astrocytes.
Acetylcysteine ; Actin Cytoskeleton ; Animals ; Astrocytes* ; Blotting, Western ; Colchicine ; Cytochalasin D ; Fibroblasts* ; Humans ; Microtubules ; Polymerization ; Polymers ; Rats* ; Staurosporine* ; Tubulin

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Hypoxia Inducible Factor-1alpha Directly Induces the Expression of Receptor Activator of Nuclear Factor-kappaB Ligand in MLO-Y4 Osteocytes.

Kyunghwa BAEK ; Hyun Jung PARK ; Jeong Hwa BAEK

International Journal of Oral Biology.2015;40(1):19-25. doi:10.11620/IJOB.2015.40.1.019

Osteocytes may function as mechanotransducers by regulating local osteoclastogenesis. Reduced availability of oxygen, i.e. hypoxia, could occur during disuse, bone development, and fracture. Receptor activator of nuclear factor-kappaB ligand (RANKL) is an osteoblast/stromal cell derived essential factor for osteoclastogenesis. The hypoxia induced osteoclastogenesis via increased RANKL expression in osteoblasts was demonstrated. Hypoxic regulation of gene expression generally involves activation of the hypoxia-inducible factor (HIF) transcription pathway. In the present study, we investigated whether hypoxia regulates RANKL expression in murine osteocytes and HIF-1alpha mediates hypoxia-induced RANKL expression by transactivating RANKL promoter, to elucidate the role of osteocyte in osteoclastogenesis in the context of hypoxic condition. The expression levels of RANKL mRNA and protein, as well as hypoxia inducible factor-1alpha (HIF-1alpha) protein, were significantly increased in hypoxic condition in MLO-Y4s. Constitutively active HIF-1alpha alone significantly increased the levels of RANKL expression in MLO-Y4s under normoxic conditions, whereas dominant negative HIF-1alpha blocked hypoxia-induced RANKL expression. To further explore to find if HIF-1alpha directly regulates RANKL transcription, a luciferase reporter assay was conducted. Hypoxia significantly increased RANKL promoter activity, whereas mutations of putative HIF-1alpha binding elements in RANKL promoter prevented this hypoxia-induced RANKL promoter activity in MLO-Y4s. These results suggest that HIF-1alpha mediates hypoxia-induced up-regulation of RANKL expression, and that in osteocytes of mechanically unloaded bone, hypoxia enhances osteoclastogenesis, at least in part, via an increased RANKL expression in osteocytes.
Anoxia* ; Bone Development ; Gene Expression Regulation ; Luciferases ; Osteoblasts ; Osteocytes* ; Oxygen ; RANK Ligand* ; RNA, Messenger ; Up-Regulation

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House Dust Mite Extract Induces PLC/IP3-dependent Ca2+ Signaling and IL-8 Expression in Human Gingival Epithelial Cells.

Ga Yeon SON ; Aran SON ; Wonse PARK ; Dong Min SHIN

International Journal of Oral Biology.2015;40(1):11-17. doi:10.11620/IJOB.2015.40.1.011

The gingival epithelium of the oral cavity is constantly exposed to exogenous stimuli such as bacterial toxins, allergens, and thermal changes. These exogenous stimuli are resisted by innate host defense in gingival epithelial cells. However, it is unclear exactly how the exogenous stimuli affect detrimentally on the human gingival epithelial cells. Here, we investigated whether the allergen, such as house dust mite (HDM) extract, is linked to Ca2+ signaling and proinflammatory cytokine expression in primary cultured human gingival epithelial cells. HDM extract induced an increase in intracellular Ca2+ concentration ([Ca2+]i) in a dose-dependent manner. Extracellular Ca2+ depletion did not affected on the HDM extract-induced increase in [Ca2+]i. The HDM extract-induced increase in [Ca2+]i was abolished by the treatment with U73122 and 2-APB, which are inhibitors of phospholipase C (PLC) and inositol 1,4,5-trisphosphate (IP3) receptor. Moreover, HDM extract induced the mRNA expression of pro-inflammatory cytokine, interleukin (IL)-8. These results suggest that HDM extract triggers PLC/IP3-dependent Ca2+ signaling and IL-8 mRNA expression in primary cultured human gingival epithelial cells.
Allergens ; Bacterial Toxins ; Epithelial Cells* ; Epithelium ; Humans ; Inositol 1,4,5-Trisphosphate ; Interleukin-8* ; Interleukins ; Mouth ; Pyroglyphidae* ; RNA, Messenger ; Type C Phospholipases

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Osteocalcin Expression and Mineralization in Developing Tooth of Xenopus laevis.

Jung Hoe PARK ; Ki tak KWON ; Byung Keon PARK ; Young Hoon LEE

International Journal of Oral Biology.2015;40(1):1-9. doi:10.11620/IJOB.2015.40.1.001

Osteocalcin (OC) is the most abundant noncollagenous protein of extracellular matrix in the bone. In an OC deficient mouse, bone formation rates are increased in cancellous and cortical bones. OC is known as a negative regulator of mineral apposition. OC is also expressed in the tooth of the rat, bovine, and human. However, little is known about OC during tooth development in Xenopus. The purpose of this study is to compare the expression of OC with mineralization in the developing tooth of Xenopus, by using von Kossa staining and in situ hybridization. At stage 56, the developmental stage of tooth germ corresponds to the cap stage, and an acellular zone was apparent between the dental papilla and the enamel organ. From stage 57, calcium deposition was revealed by von Kossa staining prior to OC expression, and the differentiated odontoblasts forming predentin were located at adjoining predentin. At stage 58, OC transcripts were detected in the differentiated odontoblasts. At stage 66, OC mRNA was expressed in the odontoblasts, which was aligned in a single layer at the periphery of the pulp. These findings suggest that OC may play a role in mineralization and odontogenesis of tooth development in Xenopus.
Animals ; Calcium ; Dental Papilla ; Enamel Organ ; Extracellular Matrix ; Humans ; In Situ Hybridization ; Mice ; Odontoblasts ; Odontogenesis ; Osteocalcin* ; Osteogenesis ; Rats ; RNA, Messenger ; Tooth Germ ; Tooth* ; Xenopus ; Xenopus laevis*

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