1.Morphological evidences in circumvallate papilla and von Ebners' gland development in mice.
Wern Joo SOHN ; Gi Jeong GWON ; Chang Hyeon AN ; Cheil MOON ; Yong Chul BAE ; Hitoshi YAMAMOTO ; Sanggyu LEE ; Jae Young KIM
Anatomy & Cell Biology 2011;44(4):274-283
In rodents, the circumvallate papilla (CVP), with its underlying minor salivary gland, the von Ebners' gland (VEG), is located on the dorsal surface of the posterior tongue. Detailed morphological processes to form the proper structure of CVP and VEG have not been properly elucidated. In particular, the specific localization patterns of taste buds in CVP and the branching formation of VEG have not yet been elucidated. To understand the developmental mechanisms underlying CVP and VEG formation, detailed histological observations of CVP and VEG were examined using a three-dimensional computer-aided reconstruction method with serial histological sections and pan-Cytokeratins immunostainings. In addition, to define the developmental processes in CVP and VEG formation, we examined nerve innervations and cell proliferation using microinjections of AM1-43 and immunostainings with various markers, including phosphoinositide 3-kinase, Ki-67, PGP9.5, and Ulex europaeus agglutinin 1 (UEA1). Results revealed specific morphogenesis of CVP and VEG with nerve innervations patterns, evaluated by the coincided localization patterns of AM1-43 and UEA1. Based on these morphological and immunohistochemical results, we suggest that nerve innervations and cell proliferations play important roles in the positioning of taste buds in CVP and branching morphogenesis of VEG in tongue development.
Animals
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Cell Proliferation
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Mice
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Microinjections
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Morphogenesis
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Rodentia
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Salivary Glands, Minor
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Taste Buds
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Tongue
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Ulex
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von Ebner Glands
2.Alteration of cellular events in tooth development by chemical chaperon, Tauroursodeoxycholic acid treatment
Eui-Seon LEE ; Yam Prasad ARYAL ; Tae-Young KIM ; Elina POKHAREL ; Harim KIM ; Shijin SUNG ; Wern-Joo SOHN ; Youngkyun LEE ; Chang-Hyeon AN ; Jae-Young KIM
International Journal of Oral Biology 2020;45(4):190-196
Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.
3.Implications of specific gene expression patterns in enamel knot in tooth development
Tae-Young KIM ; Sanjiv NEUPANE ; Yam Prasad ARYAL ; Eui-Seon LEE ; Ji-Youn KIM ; Jo-Young SUH ; Youngkyun LEE ; Wern-Joo SOHN ; Seo-Young AN ; Jung-Hong HA ; Chang-Hyeon AN ; Jae-Young KIM
International Journal of Oral Biology 2020;45(1):25-31
Enamel knot (EK)—a signaling center—refers to a transient morphological structure comprising epithelial tissue. EK is believed to regulate tooth development in early organogenesis without its own cellular alterations, including proliferation and differentiation. EKs show a very simple but conserved structure and share functions with teeth of recently evolved vertebrates, suggesting conserved signaling in certain organs, such as functional teeth, through the course of evolution. In this study, we examined the expression patterns of key EK-specific genes including Dusp26 , Fat4, Meis2, Sln , and Zpld1 during mice embryogenesis. Expression patterns of these genes may reveal putative differentiation mechanisms underlying tooth morphogenesis.