• Applied Microscopy
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• v.47 no.1
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• pp.8-12
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• 2017

The ultrastructures of the secretory acinar granules of submandibular and parotid salivary gland were examined in the Korean striped field mouse, Apodemus agraius. The acini of the submandibular salivary gland had serous and mucous acinar cells filled with numerous secretory granules. The serous acinar granules had uniformly fine dense contents and were round typed with a definite boundary between the granules. The mucous acinar granules were relatively coarse, with moderate density, and clustered together as a result of the indistinct boundaries between the granules. The acini of the parotid salivary glands contained only serous cells filled with numerous round-typed serous acinar granules. Serous acinar granules had uniformed dense matrix and definite boundaries. The ultrastructures without substructure in a matrix of serous and mucous acinar granules in the submandibular and parotid salivary glands of A. agraius were similar to those of species of Rodentia but different from those of Soricidae in Korea with a characteristic substructure in a matrix. This ultrastructure and charateristics in secretory acinar granules provide fundamental data for molecular comparisions of genetic relationships and are one of the key methods for classifying A. agraius.

• International Journal of Oral Biology
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• v.33 no.4
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• pp.125-129
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• 2008

Inositol 1,4,5-trisphosphate ($IP_3$) plays an important role in the release of $Ca^{2+}$ from intracellular stores into the cytoplasm in a variety of cell types. $IP_3$ translocation dynamics have been studied in response to many types of cell signals. However, the dynamics of cytosolic $IP_3$ in salivary acinar cells are unclear. A green fluorescent protein (GFP)-tagged pleckstrin homology domain (PHD) was constructed and introduced into a phospholipase C ${\delta}1$ (PLC ${\delta}1$) transgenic mouse, and then the salivary acinar cells were isolated. GFP-PHD was heterogeneously localized at the plasma membrane and intracellular organelles in submandibular gland and parotid gland cells. Application of trypsin, a G protein-coupled receptor activator, to the two types of cells caused an increase in GFP fluorescence in the cell cytoplasm. The observed time course of trypsin-evoked $IP_3$ movement in acinar cells was independent of cell polarity, and the fluorescent label showed an immediate increase throughout the cells. These results suggest that GFP-PHD in many tissues of transgenic mice, including non-cultured primary cells, can be used as a model for examination of $IP_3$ intracellular dynamics.

• Animal cells and systems
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• v.1 no.3
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• pp.463-466
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• 1997

We have recently demonstrated, by protein and cDNA sequence analysis, that prorenin converting enzyme (PRECE) in the mouse submandibular gland is identical to the epidermal growth factor-binding protein (EGF-BP)type B. However, type A and C did not show prorenin converting activity. To demonstrate whether r-NGF is involved in prorenin processing, we have cloned cDNA of r-NGF and examined prorenin converting activity using the CHO cell expression system, Trypsin converted the 33 kDa r-NGF precursor produced in CHO cells to a two-chain form, 9.4 and 16.4 kDa polypeptide chains, which has been known as an active form of r-NGF in mouse SMG (Server and Shooter, 1976). However, the two chain forms of r-NGF did not reveal prorenin-processing activity. Thus, only PRECE is involved in prorenin processing in mouse SMG. This result shows that their substrate specificities appear to be very strict, although some kallikreins share a high degree of amino acid sequence identity.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.525-530
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• 2014

Transient receptor potential vanilloid subtype 1 (TRPV1) was originally found in sensory neurons. Recently, it has been reported that TRPV1 is expressed in salivary gland epithelial cells (SGEC). However, the physiological role of TRPV1 in salivary secretion remains to be elucidated. We found that TRPV1 is expressed in mouse and human submandibular glands (SMG) and HSG cells, originated from human submandibular gland ducts at both mRNA and protein levels. However, capsaicin (CAP), TRPV1 agonist, had little effect on intracellular free calcium concentration ($[Ca^{2+}]_i$) in these cells, although carbachol consistently increased $[Ca^{2+}]_i$. Exposure of cells to high temperature (> $43^{\circ}C$) or acidic bath solution (pH5.4) did not increase $[Ca^{2+}]_i$, either. We further examined the role of TRPV1 in salivary secretion using TRPV1 knock-out mice. There was no significant difference in the pilocarpine (PILO)-induced salivary flow rate between wild-type and TRPV1 knock-out mice. Saliva flow rate also showed insignificant change in the mice treated with PILO plus CAP compared with that in mice treated with PILO alone. Taken together, our results suggest that although TRPV1 is expressed in SGEC, it appears not to play any direct roles in saliva secretion via transcellular pathway.

• BMB Reports
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• v.30 no.5
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• pp.356-361
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• 1997

We cloned a cDNA (pPRC-1) which was comprised of 841 nucleotides from the cDNA library of a male ICR mouse submandibular gland ($SMG^+$). The nucleotide sequences of pPRC-1 were identical to those of exons 2 and 3 of the mGK-21 gene, a potentially functional glandular kallikrein identified in a Balb/c mouse, except for one nucleotide residue. Although this substitution changes Ile (ATT) in pPRC-1 to Val (GTT) in mGK-21, this difference has been explained by strain polymorphism. From the amino acid sequences predicted from its cDNA, we speculated that mGK-21 gene products/pGK21 consist of 261 amino acids including the $NH_2$-terminal signal peptide (residues 1~17), the short propeptide (residues 17~24), and the active peptide (residues 25~261). Although we did not demonstrate the enzyme activity of pGK21, it was assumed that pGK 21 was involved in the maturation of certain bioactive polypeptide(s) in mouse SMG for the following reasons : (a) mGK-21 gene was apparently expressed in a male ICR mouse SMG: (b) the proposed active site $His^{65}$, $Asp^{120}$, and $Ser^{213}$ residues were completely conserved in pGK21 just like other glandular kallikreins; (c) the cloned cDNA was translated to a predicted 27 kDa polypeptide chain in vitro: (d) the 27 kDa polypeptide chain produced by CHO cells was produced to a putative active form by trypsin.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.215-222
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• 1996

In the previous studies, we have demonstrated that prorenin converting enzyme (PRECE) was identical to the epidermal grouch factor-binding protein (EGF-BP) type B, which was a member of the mouse glandular kallikrein family, To examine whether or not EGF-BP type A and C are involved in the processing of prorenin, we have cloned the CDNAS of the EGF-BP type h and C from a library of male ICR mouse submandibular gland (SMGI. And then CHO cells were transfected with the EGF-BP expression plasmids. and stable cell lines expressing a high level of the EGF-BPS precursor were obtained. The conditioned medium was then treated with trypsin, which has been knotvn to effectively convert the EGF-BP type A and C precursor to the active forms. 수ubsequentlv, the prorenin converting activity of the trypsin-treated or untreated medium was examined. PRECE converted exactly prorenin to renin, but the prorenin converting activities of EGF-BP type A and C were not detected. From these results, it seems that only type B of these EGF-BPs is involved in processing Ren 2 prorenin in mouse SMG.

• The Korean Journal of Zoology
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• v.34 no.2
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• pp.148-158
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• 1991

The purpose of this research was to establish the culture condition for dissociated submandibu -lar gland (SG) cells. After trypsin digestion of SG from 3-4 weeks old mice, dissociated cells were cultured in 1OO/o fetal bovine serum-Dulbecco's modified Eagle's medium (FBS-DME) or 0.5-2% low protein serum replacement-DME (LPSR-DME) on plastic surface to form monolayer. The effects of FBS, LPSR and hormones on the growth and function of cultured SG cells were examined. SG cells dissociated by enzyme were successfully cultured and were characterized as epithelial-like cells by light and electron microscope. The maximal DNA synthesis of cultured SG cells was achieved by DME containing 5-10% FBS. The same results were obtained when the effects of LPSR on cell proliferation were examined up to a LPSR concentration of 2%. SG cells cultured in 20/o LPSR-DME expressed a population doubling time of 42.5 hrs and a saturation density of 1.2 $\times$10 5cell/cm$^2$. Dihydrotestosterone (DHT) in medium did not influence on the DNA synthesis of the cultured SG cells, but stimulated protein synthesis of the SG cells. Thyroxine (T4) stimulated protein synthesis of the SCI cells markedly in a dose-dependent fashion. EGF secretion by the cultured SG cells increased significandy by DHT and or T4 trearment. This finding indicated that secretion of EGF by the SG cells was under the control of the hormones such as androgen and thyroid hormones. It seems to be that the culture condition described here can be used as a useful tool for further research on the SCI cells.

• The Journal of Korean Society for Radiation Therapy
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• v.4 no.1
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• pp.71-77
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• 1990

The present study was undertaken to investigate effects of ionizing radiation on DNA synthesis and chromosomal abnormality in cultured submandibular gland(SG) cells. SG cells from C57BL/6N Crj mice were cultured in Dulbecco's modified Eagle's medium (DME) supplemented with $10\%$ fetal bovine serum, antibiotics and fungizone. The cultured SG cells were irradiated with graded doses of gamma ray ($^{60}Co$) at a dose rate of 58.4rad/min. The effect of irradiation of $^{60}Co$ on DNA synthesis in cultured cells was evaluated by measuring the incorporation of 3H-TdR. Using conventional chromosome techniques and Giemsa staining methods, chromosomal abnormalities in cultured SG cells, induced by irradiation of $^{60}Co$ werw examined. Cytological observations were carried out by a light microscope with high resolving power. The results obtained were as follows : 1. DNA synthesis of SG cells was quantitatively dependent on a radiation dose compare to control. 2. A polyploids and few chromosome-type break, such as single and double breaks, deltions and triradial figures were more predominantly in irradiated SG cells than in control. This increase of chromosomal abnormality was in the proposition to the irradiation doses.

• Biomedical Science Letters
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• v.11 no.3
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• pp.311-318
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• 2005

Grp78, discovered as one of the putative target genes of Hoxc8, is a highly conserved stress protein and functions as a molecular chaperone in the endoplasmic reticulum (ER). In order to see the stage-specific expression pattern of Grp78 during development, mouse embryos from day 7.5 to 17.5 p.c. were isolated, and RT-PCR as well as in situ hybridization was performed. When RT-PCR was performed using Grp78 specific primers, periodic expression pattern was detected. And also a region-specific expression pattern was detected with a strong expression in the trunk part of day 11.5 p.c. embryo, like that of Hoxc8. When in situ hybridization was performed, Grp78 was revealed to be expressed in the endoderm, somite, neuroepithelium cells of neural tube in early embryos. In the case of late embryos, Grp78 expression was detected in the liver, segmental bronchus within cranial lobe of lung, ossification center within the cartilage primordium of rib and vertebra, submandibular gland, as well as metanephros. These expression patterns are very much similar to those of Hoxc8. Since Hoxc8 has been reported to regulate apoptosis during organogenesis, it might be possible that the apoptotic function could have been conveyed through the expression of Grp78, implying that the Grp78 is one of the Hoxc8 downstream target genes.

• IMMUNE NETWORK
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• v.21 no.5
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• pp.34.1-34.16
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• 2021

Sjögren's syndrome (SS) is an autoimmune disease characterized by dryness of the mouth and eyes. The glandular dysfunction in SS involves not only T cell-mediated destruction of the glands but also autoantibodies against the type 3 muscarinic acetylcholine receptor or aquaporin 5 (AQP5) that interfere with the secretion process. Studies on the breakage of tolerance and induction of autoantibodies to these autoantigens could benefit SS patients. To break tolerance, we utilized a PmE-L peptide derived from the AQP5-homologous aquaporin of Prevotella melaninogenica (PmAqp) that contained both a B cell "E" epitope and a T cell epitope. Repeated subcutaneous immunization of C57BL/6 mice with the PmE-L peptide efficiently induced the production of Abs against the "E" epitope of mouse/human AQP5 (AQP5E), and we aimed to characterize the antigen specificity, the sequences of AQP5E-specific B cell receptors, and salivary gland phenotypes of these mice. Sera containing anti-AQP5E IgG not only stained mouse Aqp5 expressed in the submandibular glands but also detected PmApq and PmE-L by immunoblotting, suggesting molecular mimicry. Characterization of the AQP5E-specific autoantibodies selected from the screening of phage display Ab libraries and mapping of the B cell receptor repertoires revealed that the AQP5E-specific B cells acquired the ability to bind to the Ag through cumulative somatic hypermutation. Importantly, animals with anti-AQP5E Abs had decreased salivary flow rates without immune cell infiltration into the salivary glands. This model will be useful for investigating the role of anti-AQP5 autoantibodies in glandular dysfunction in SS and testing new therapeutics targeting autoantibody production.