No abstract available.
Adult* ; Dental Pulp Cavity* ; Humans ; Incisor*

Immunohistochemical changes of epidermal growth factor receptor (EGFR) and nerve growth factor receptor (NGFR) were investigated in the rat mandibular molar and incisors after submandibular sialadenectomy. In the sham operated rat, any EGFR immunoreactivity was not observed in the teeth but NGFR immunoreactivities were observed exclusively in the periodontal ligament and ameloblasts of incisor. In the sialadenectomized rat, EGFR immunoreac-tivities were observed in the odontoblasts of the mandibular first molar, periodontal ligament cells, ameloblasts of incisor and some cells of bone marrow. NGFR immunoreactivities were more intense and widely distributed in alveolar bone, periodontal ligaments and odontoblasts of the sialadenectomized rat than in the sham operated rat. Both of EGFR and NGFR immunoreactivities gradually increased in their intensities in a time-dependent manner after submandibular sialadenectomy. The results show that expression of EGFR and NGFR in the mandibular molar and incisor is enhanced by submandibular sialadenectomy. Therefore, it is suggested that EGF and NGF derived from submandibular gland may affect to the mandibular molar and incisors by direct and/or indirect mechanism.
Ameloblasts ; Animals ; Bone Marrow ; Epidermal Growth Factor* ; Immunohistochemistry ; Incisor* ; Molar* ; Nerve Growth Factor ; Odontoblasts ; Periodontal Ligament ; Rats* ; Receptor, Epidermal Growth Factor* ; Submandibular Gland ; Tooth

The immunohistochemical localization of epidermal growth factor receptor (EGFR) and nerve growth factor receptor (NGFR) in the submandibular gland of rats was investigated after chronic administration of isoproterenol (IPR) or phenylephrine (PEP). The weight of submandibular gland relative to body weight increased sharply by IPR administration for 14 days and reached twice of that in control, while no significant differences were observed after PEP administration. In PTAH staining, the intensity of duct compartments in rats exposed to IPR and PEP were paler than that of controls. But small secretory granules were observed in the GCT cells of IPR administrated groups. Acini showed characteristic features of hypertrophy, decreased in number of nuclei per unit area, after IPR administration, but not after PEP. EGFR immunoreactivities were distributed mainly in the duct compartments including GCT cells, intercalated duct cells and secretory duct cells. EGFR immunoactivities were more intense after both of PEP and IPR administration than those in controls. However, EGFR immunoactivities gradually decreased after IPR administration. NGFR immunoreactivities were distributed mainly in connective tissue cells surrounding ducts, but not in duct cells. Their intensities increased in the rat with PEP administration but decreased by IPR administration. These results demonstrated that EGFR or NGFR is localized mainly in the duct cells or the cells surrounding ducts, respectively, and that both population of EGFR and NGFR immunoreactive cells are altered by PEP and IPR. The results suggest that EGF and NGF may have some physiological roles by binding with their specific receptors in the submandibular gland as well as oral cavity.
Animals ; Body Weight ; Connective Tissue Cells ; Epidermal Growth Factor* ; Hypertrophy ; Immunohistochemistry ; Isoproterenol ; Mouth ; Nerve Growth Factor ; Phenylephrine ; Rats* ; Receptor, Epidermal Growth Factor* ; Secretory Vesicles ; Submandibular Gland*

No abstract available.
Animals ; Histamine Release* ; Histamine* ; Mast Cells* ; Rats*

C-type natriuretic peptide (CNP), a member of natriuretic peptide family, is mainly synthesized in the endothelium and central nervous system. But CNP is also involved in the growth and differentiation of other peripheral organs. Although we have reported the local synthesis and localization of CNP in the adult submandibular glands (SMG), it is not known that the expression and biological activity of CNP following the morphogenesis, differentiation and aging. This study aimed to examine the expression of CNP and its receptors in the developing and differentiating stages of mouse SMG, and the changes of biological activity of its receptors with aging. The SMG, obtained from 14, 16, 18 days-old embryos (E) and 1 day, 2 weeks, 1, 2, 12, and 24 month-old C57BL/6N mouse, were processed for RT-PCR, in situ hybridization, immunohistochemistry and cGMP assay. CNP was strongly expressed in the epithelial clusters of primitive SMG, which was maintained before birth but was markedly decreased after birth. CNP was localized in the intercalated duct and granular convoluted tubules of adult SMG, where NPRC was specifically expressed but NPRB was not. CNP mRNA was gradually decreased from E16 to 2 M but ANP mRNA was opposed. NPRB and NPRC were the same pattern of the expression of CNP but NPRA was weakly expressed. In addition, CNP mRNA was also expressed in the craniofacial tissues such as tooth germs, tongue, premaxilla and bone forming area in which NPRC was specifically expressed but NPRB was not. In the SMG of 2 M, the membrane of duct cells markedly produced cGMP by CNP whereas acini produced cGMP by ANP and BNP rather than CNP. The biological activity of cGMP production of SMG gradually decreased with age. cGMP production was dominant by CNP in SMG of 1M but was by ANP after 2M. These results shows that CNP may play roles both in the morphogenesis and differentiation via NPRC and in the maintenance of duct system via NPRB in the mouse SMG and that the biological activity of its receptors may decreased with aging.
Adult ; Aging* ; Animals ; Atrial Natriuretic Factor ; Central Nervous System ; Child, Preschool ; Embryonic Development* ; Embryonic Structures ; Endothelium ; Female ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Membranes ; Mice* ; Morphogenesis ; Natriuretic Peptide, C-Type* ; Parturition ; Pregnancy ; Receptors, Peptide* ; RNA, Messenger ; Submandibular Gland* ; Tongue ; Tooth Germ

A T-box transcription factor gene, Tbx1 is a principal candidate of the most frequent chromosomal deletion syndrome found in human, DiGeorge/velocardiofacial syndrome which is a complex developmental disorder associated with cardiac outflow tract abnormalities, mid facial dysmorphology, velopharyngeal insufficiency and submucosal cleft palate. We performed in situ hybridization against mouse embryo from E13.5 (bud stage) to E18.5 (late bell stage) in order to analyze the expression patterns of Tbx1 in the developing mouse first molar, a derivative of the first pharyngeal arch. Tbx1 transcripts were found in the dental lamina and its surrounding mesenchyme at E13.5 and in the dental organ except enamel knot at E14.5 (cap stage). Tbx1 was strongly expressed in the cervical loop and stratum intermedium but was weak in the dental papilla and dental follicle at E15.5 (early bell stage). At E18.5, Tbx1 was strongly expressed not only in the dental organ (bell stage) except stellate reticulum but also dental papilla and dental follicle adjacent to the inner dental epithelium. In conclusion, Tbx1 transcripts were specifically expressed both in the dental epithelium and surrounding mesenchyme of developing tooth from initiation to bell stage, which were the most similar with those of Sox9 but little different from those of Pitx2 and ectodin. These results strongly suggested that Tbx1 may play a role as a transcription factor regulating proliferation and differentiation of both dental epithelium and mesenchyme through the tooth development.
Animals ; Branchial Region ; Cleft Palate ; Dental Enamel ; Dental Papilla ; Dental Sac ; Embryonic Structures ; Epithelium ; Humans ; In Situ Hybridization ; Mesoderm ; Mice* ; Molar* ; Reticulum ; Tooth ; Transcription Factors ; Velopharyngeal Insufficiency

PURPOSE: Wnt signaling plays an essential role in the dental epithelium and mesenchyme during tooth morphogenesis. Deletion of the Wntless (Wls) gene in odontoblasts appears to reduce canonical Wnt activity, leading to inhibition of odontoblast maturation. However, it remains unclear if autonomous Wnt ligands are necessary for differentiation of dental pulp cells into odontoblast-like cells to induce reparative dentinogenesis, one of well-known feature of pulp repair to form tertiary dentin. MATERIALS AND METHODS: To analyze the autonomous role of Wls for differentiation of dental pulp cells into odontoblast-like cells, we used primary dental pulp cells from unerupted molars of Wls-floxed allele mouse after infection with adenovirus for Cre recombinase expression to knockout the floxed Wls gene or control GFP expression. The differentiation of dental pulp cells into odontoblast-like cells was analyzed by quantitative real-time polymerase chain reaction. RESULT: Proliferation rate was significantly decreased in dental pulp cells with Cre expression for Wls knockout. The expression levels of Osterix (Osx), runt-related transcription factor 2 (Runx2), and nuclear factor I-C (Nfic) were all significantly decreased by 0.3-fold, 0.2-fold, and 0.3-fold respectively in dental pulp cells with Wls knockout. In addition, the expression levels of Bsp, Col1a1, Opn, and Alpl were significantly decreased by 0.7-fold, 0.3-fold, 0.8-fold, and 0.6-fold respectively in dental pulp cells with Wls knockout. CONCLUSION: Wnt ligands produced autonomously are necessary for proper proliferation and odontoblastic differentiation of mouse dental pulp cells toward further tertiary dentinogenesis.
Adenoviridae ; Alleles ; Animals ; Dental Pulp* ; Dentin ; Dentinogenesis ; Epithelium ; Ligands ; Mesoderm ; Mice* ; Molar ; Morphogenesis ; NFI Transcription Factors ; Odontoblasts* ; Real-Time Polymerase Chain Reaction ; Recombinases ; Tooth ; Transcription Factors

Tooth is formed by the reciprocal interactions between the ectoderm and ectomesenchyme derived from neural crest. It has not been clear that neuronal factors involved in the morphogenesis and differentiation of tooth. To identify the roles of neuronal factors during the tooth development, the expression patterns and localization of Uchl1 were investigated in the developing mouse tooth germ by in situ hybridization and immunohistochemistry. Uchl1 transcripts were weakly expressed in the oral epithelium and dental lamina at bud stage. However, expression of Uchl1 was not found in the oral epithelium from cap stage and observed in the inner enamel epithelium, stellate reticulum and dental papilla. From the bell stage, Uchl1 was expressed in the inner enamel epithelium and ameloblasts. Uchl1, was appeared to be localized in the inner enamel epithelium and differentiating ameloblasts of molar and incisors at neonates. Uchl1 was localized strongly in the fully differentiated ameloblasts and adjacent papillary layer whereas localized weakly in the odontoblasts of the molar at postnatal day 5. From these results, Uchl1 was expressed and localized in the differentiating dental epithelium and ameloblasts during tooth development. The results suggest that neuronal protein, Uchl1 may play roles in the histo- and cyto-differentiation of non-neuronal dental epithelium.
Ameloblasts ; Animals ; Dental Enamel ; Dental Papilla ; Ectoderm ; Epithelium* ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Incisor ; Infant, Newborn ; Mice* ; Molar ; Morphogenesis ; Neural Crest ; Neurons ; Odontoblasts ; Reticulum ; Tooth Germ ; Tooth*

Cholinesterase (ChE) is one of the most ubiquitous enzymes and in addition to its well characterized catalytic function, the morphogenetic involvement of ChE has also been demonstrated in neuronal tissues and in non-neuronal tissues such as bone and cartilage. We have previously reported that during mouse tooth development, acetylcholinesterase (AChE) activity is dynamically localized in the dental epithelium and its derivatives whereas butyrylcholinesterase (BuChE) activity is localized in the dental follicles. To test the functional conservation of ChE in tooth morphogenesis among different species, we performed cholinesterase histochemistry following the use of specific inhibitors of developing molar and incisors in the hamster from embryonic day 11 (E11) to postnatal day 1 (P1). In the developing molar in hamster, the localization of ChE activity was found to be very similar to that of the mouse. At the bud stage, no ChE activity was found in the tooth buds, but was first detectable in the dental epithelium and dental follicles at the cap and bell stages. AChE activity was found to be principally localized in the dental epithelium whereas BuChE activity was observed in the dental follicle. In contrast to the ChE activity in the molars, BuChE activity was specifically observed in the secretory ameloblasts of the incisors, whilst no AChE activity was found in the dental epithelium of incisors. The subtype and localization of ChE activity in the dental epithelium of the incisor thus differed from those of the molar in hamster. In addition, these patterns also differed from the ChE activity in the mouse incisor. These results strongly suggest that ChE may play roles in the differentiation of the dental epithelium and dental follicle in hamster, and that morphogenetic subtypes of ChE may be variable among species and tooth types.
Acetylcholinesterase ; Ameloblasts ; Animals ; Butyrylcholinesterase ; Cartilage ; Cholinesterases ; Cricetinae ; Dental Sac ; Epithelium ; Incisor ; Mice ; Molar ; Morphogenesis ; Neurons ; Tooth ; Tooth Germ

Genetically engineered mice have provided much information about gene function in the field of developmental biology. Recently, conditional gene targeting using the Cre/loxP system has been developed to control the cell type and timing of the target gene expression. The increase in number of kidney-specific Cre mice allows for the analysis of phenotypes that cannot be addressed by conventional gene targeting. The mammalian kidney is a vital organ that plays a critical homeostatic role in the regulation of body fluid composition and excretion of waste products. The interactions between epithelial and mesenchymal cells are very critical events in the field of developmental biology, especially renal development. Kidney development is a complex process, requiring inductive interactions between epithelial and mesenchymal cells that eventually lead to the growth and differentiation of multiple highly specialized stromal, vascular, and epithelial cell types. Through the use of genetically engineered mouse models, the molecular bases for many of the events in the developing kidney have been identified. Defective morphogenesis may result in clinical phenotypes that range from complete renal agenesis to diseases such as hypertension that exist in the setting of grossly normal kidneys. In this review, we focus on the growth and transcription factors that define kidney progenitor cell populations, initiate ureteric bud branching, induce nephron formation within the metanephric mesenchyme, and differentiate stromal and vascular progenitors in the metanephric mesenchyme.
Animals ; Body Fluids ; Congenital Abnormalities ; Developmental Biology ; Epithelial Cells ; Gene Expression ; Gene Targeting ; Hypertension ; Kidney ; Kidney Diseases ; Mesoderm ; Mice ; Morphogenesis ; Nephrons ; Phenotype ; Stem Cells ; Transcription Factors ; Ureter ; Waste Products