• Journal of Medicine and Life Science
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• v.19 no.3
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• pp.130-133
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• 2022

Several studies have reported a possible link between anti-aquaporin-4 antibody and vitamin B12 deficiency in neuromyelitis optica spectrum disorder (NMOSD). Bilaterally symmetric hyperintense signals on magnetic resonance imaging (MRI) of the posterior columns, called the inverted V sign, are a characteristic feature of subacute combined degeneration associated with vitamin B12 deficiency. We report a patient with anti-aquaporin-4 antibody-positive NMOSD and an inverted V sign on MRI of the spinal cord and address the association between anti-aquaporin-4 antibody and functional vitamin B12 deficiency.

• KSBB Journal
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• v.28 no.6
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• pp.394-399
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• 2013

Astragalus membranaceus Bunge is used in herbal medicine in Eastern Asian countries including Korea. In this study, we assessed the effects of A. membranaceus extract (AM) on the aquaporin-3 (AQP3) protein expression in HaCaT cells. AM did not affect viability of HaCaT cells. AQP3 expression and cell migration seem to be maximal at $100{\mu}g/mL$ concentration. Epidermal growth factor receptor (EGFR) kinase inhibitor, PD153035, blocked AM-induced AQP3 expression and cell migration. In addition, an 80% ethanol extracts of herbal prescription, SinhyoTakleesan (ST), which is composed of A. membranaceus, Angelicae gigantis, Glycyrrhiza glabra Linne, and Lonicera japonica Flos also induced AQP3 expression at $20{\mu}g/mL$ in HaCaT cells. Collectively, these results suggest that AM induce AQP3 expression via EGFR pathway.

• International Journal of Oral Biology
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• v.44 no.2
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• pp.62-70
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• 2019

Xylitol is well-known to have an anti-caries effect by inhibiting the replication of cariogenic bacteria. In addition, xylitol enhances saliva secretion. However, the precise molecular mechanism of xylitol on saliva secretion is yet to be elucidated. Thus, in this study, we aimed to investigate the stimulatory effect of xylitol on saliva secretion and to further evaluate the involvement of xylitol in muscarinic type 3 receptor (M3R) signaling. For determining these effects, we measured the saliva flow rate following xylitol treatment in healthy individuals and patients with dry mouth. We further tested the effects of xylitol on M3R signaling in human salivary gland (HSG) cells using real-time quantitative reverse-transcriptase polymerase chain reaction, immunoblotting, and immunostaining. Xylitol candy significantly increased the salivary flow rate and intracellular calcium release in HSG cells via the M3R signaling pathway. In addition, the expressions of M3R and aquaporin 5 were induced by xylitol treatment. Lastly, we investigated the distribution of M3R and aquaporin 5 in HSG cells. Xylitol was found to activate M3R, thereby inducing increases in $Ca^{2+}$ concentration. Stimulation of the muscarinic receptor induced by xylitol activated the internalization of M3R and subsequent trafficking of aquaporin 5. Taken together, these findings suggest a molecular mechanism for secretory effects of xylitol on salivary epithelial cells.

• Ocean and Polar Research
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• v.38 no.2
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• pp.103-113
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• 2016

This study aimed to examine the role of two aquaporin isoforms (AQP3 and AQP8) in response to the hyperosmotic challenge of transitioning from freshwater (FW) to seawater (SW) during parr and smoltification (smolt) using the rainbow trout, Oncorhynchus mykiss. We examined the changes in the expression of AQPs mRNAs in the gills and intestine of the parr and smolt stages of rainbow trout transferred from FW to SW using quantitative real-time PCR in an osmotically changing environment [FW, SW, and recombinant AQP3 (rAQP3) injection at two dosage rates]. Correspondingly, AQPs were greater during smoltification than during parr stages in the rainbow trout. Plasma osmolality and gill $Na^+/K^+$-ATPase activity increased when the fish were exposed to SW, but these parameters decreased when the fish were exposed to SW following treatment with rAQP3 during the transition to seawater. Our results suggest that AQPs play an important role in water absorbing mechanisms associated with multiple AQP isoforms in a hyperosmotic environment.

• Development and Reproduction
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• v.24 no.3
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• pp.177-185
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• 2020

Although many aquaporin (AQP) transcripts have been demonstrated to express in the female reproductive tract, the defined localizations and functions of AQP subtype proteins remain unclear. In this study, we investigated the expression of AQP1, AQP3, AQP5, AQP6, and AQP9 proteins in female reproductive tract of mouse and characterized their precise localizations at the cellular and subcellular levels. Immunofluorescence analyses for AQP1, AQP3, AQP6, and AQP9 showed that these proteins were abundantly expressed in female reproductive tract and that intense immunoreactivities were observed in mucosa epithelial cells with a subtype-specific pattern. The most abundant aquaporin in both vagina and uterine cervix was AQP3. Each of AQP1, AQP3, AQP6, and AQP9 exhibited its distinct distribution in stratified squamous or columnar epithelial cells. AQP9 expression was predominant in oviduct and ovary. AQP1, AQP3, AQP6, and AQP9 proteins were mostly seen in apical membrane of ciliated epithelial cells of the oviduct as well as in both granulosa and theca cells of ovarian follicles. Most of AQP subtypes were also expressed in surface epithelial cells and glandular cells of endometrium in the uterus, but their expression levels were relatively lower than those observed in the vagina, uterine cervix, oviduct and ovary. This is the first study to investigate the expression and localization of 5 AQP subtype proteins simultaneously in female reproductive tract of mouse. Our results suggest that AQP subtypes work together to transport water and glycerol efficiently across the mucosa epithelia for lubrication, proliferation, energy metabolism and pH regulation in female reproductive tract.

• Development and Reproduction
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• v.18 no.3
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• pp.153-160
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• 2014

Adaptive development of early stage embryo is well established and recently it is explored that the mammalian embryos also have adaptive ability to the stressful environment. However, the mechanisms are largely unknown. In this study, to evaluate the possible role of aquaporin in early embryo developmental adaptation, the expression of aquaporin (AQP) 5 gene which is detected during early development were examined by the environmental condition. To compare expression patterns between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP5 by whole mount immunofluorescence. At in vivo condition, Aqp5 expressed in oocyte and in all the stages of preimplantation embryo. It showed peak at 2-cell stage and decreased continuously until morula stage. At in vitro condition, Aqp5 expression pattern was similar with in vivo embryos. It expressed both at embryonic genome activation phase and second mid-preimplantation gene activation phase, but the fold changes were modified between in vivo embryos and in vitro embryos. During in vivo development, AQP5 was mainly localized in apical membrane of blastomeres of 4-cell and 8-cell stage embryos, and then it was localized in cytoplasm. However, the main localization area of AQP5 was dramatically shifted after 8-cell stage from cytoplasm to nucleus by in vitro development. Those results explore the modification of Aqp5 expression levels and location of its final products by in vitro culture. It suggests that expression of Aqp5 and the roles of AQP5 in homeostasis can be modulated by in vitro culture, and that early stage embryos can develop successfully by themselves adapting to their condition through modulation of the specific gene expression and localization.

• Polymer(Korea)
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• v.39 no.2
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• pp.317-322
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• 2015

Salinity gradient power is a system which sustainably generates electricity for 24 hrs, if the system is constructed at a certain place where both seawater and river water are consistently pumped. Since power is critically determined by the water flux and the salt rejection, a membrane of water-semipermeable aquaporin protein in cell membranes was studied for pressure-retarded osmosis. NaCl was used as a salt, and $NaNO_3$ was used as a candidate to check the ion selectivity. The water flux of biomimetic aquaporin membranes was negligible at a concentration below 2M. Also, there is no remarkable dependence of water flux and ion selectivity on concentrations higher than 3M. Therefore, the biomimetic aquaporin membrane could not be applied into pressure-retarded osmosis; however, if a membrane could overcome the current limitations, the properties shown by natural cells could be accomplished.

• Korean Journal of Veterinary Research
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• v.47 no.4
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• pp.363-370
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• 2007

Mongolian gerbil (Meriones unguiculatus) has been as an model animal for studing the neurological disease such as stroke and epilepsy because of the congenital incompleteries in Willis circle, as well as the investigation of water metabolism because of the long time-survival in the condition of water-deprived desert condition, compared with other species animal. Aquaporin 2 (AQP2) expressed at the surface of principal cells in collecting duct results from an equilibrium between the AQP2 in intracellular vesicles and the AQP2 on the plasma membrane. Aquaporin 4 (AQP4), which is expressed in cell in a wide range of organ, is also present in the collecting duct principal cells where this is abundant in the basolateral plasma membranes and represent potential exit pathways from the cell for water entering via AQP2. In this research, we divide 3 groups of which each group include the 5 animals. In the study of 7 or 14 days water restricted condition, we investigated the AQP2 and AQP4 by using a quantitative immunohistochemistry in the kidney. The results obtained in this study were summarized as followings. AQP2 is abundant in the apical plasma membrane and apical vesicles in the collecting duct principal cell and at rare abundance in connecting tubules. In the water-deprived Mongolian gerbil kidney, expression of AQP2 was continuosly increased in the cortical collecting duct and inner medullary collecting duct. This increase was both the apical region and cytoplasm. AQP4 is mainly expressed in the inner medulla, although some expression is also noted in the more proximal segment. In the water-deprived Mongolian gerbil kidney, AQP4 was also increased in the inner medullary collecting duct. Immunoactivity was increased in entire inner medullary collecting duct and newly detected in cytoplasm of principal cell. These findings suggest that increased levels of AQP2 and AQP4 in the cortical and inner medulalry collecting duct may play a important role for maintain fluid balance in the water-deprived kidney.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.295-301
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• 2011

Aquaporin is a water channel protein, which is classified as Major Intrinsic Protein (MIP), found in almost all organisms from bacteria to human. To date, more than 200 members of this family were identified. There are two major categories of MIP channels, orthodox aquaporins and aquaglyceroporins, which facilitate the diffusion across biological membranes of water or glycerol and other uncharged compounds, respectively. The full genome sequencing of various fungal species revealed 3 to 5 aquaporins in their genome. Although some functions of aquaporins found in yeast were characterized, however, no functional characteristics were studied so far in filamentous fungi, including Aspergillus sp. In this study, one orthodox aquaporin homolog gene, aqpA, and four aquaglyceroporin homologs, aqpB-E, in a model filamentous fungus Aspergillus nidulans were identified and the function of the aqpA gene was characterized. Knock-out of the aqpA gene didn't show any obvious phenotypic change under the osmotic stress, indicating that the function of the gene does not involved in the osmotic stress response or the function could be redundant. However, the mutant showed antifungal susceptibility resistance phenotype, suggesting that the function of the aqpA gene could be involved in sensing the antifungal substances rather than the osmotic stress response.

• Development and Reproduction
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• v.22 no.3
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• pp.263-273
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• 2018

Aquaporin (AQP) 3, a facilitated transporter of water and glycerol, expresses in placenta and fetal membranes, but the detailed localization and function of AQP3 in placenta remain unclear. To elucidate a role of AQP3 in placenta, we defined the expression and cellular localization of AQP3 in placenta and fetal membranes, and investigated the structural and functional differences between wild-type and AQP3 null mice. Gestational sacs were removed during mid-gestational period and amniotic fluid was aspirated for measurements of volume and composition. Fetuses with attached placenta and fetal membranes were weighed and processed for histological assessment. AQP3 strongly expressed in basolateral membrane of visceral yolk sac cells of fetal membrane, the syncytiotrophoblasts of the labyrinthine placenta and fetal nucleated red blood cell membrane. Mice lacking AQP3 did not exhibit a significant defect in differentiation of trophoblast stem cells and normal placentation. However, AQP3 null fetuses were smaller than their control litter mates in spite of a decrease in litter size. The total amniotic fluid volume per gestational sac was reduced, but the amniotic fluid-to-fetal weight ratio was increased in AQP3 null mice compared with wild-type mice. Glycerol, free fatty acid and triglyceride levels in amniotic fluid of AQP3 null mice were significantly reduced, whereas lactate level increased when compared to those of wild-type mice. These results suggest a role for AQP3 in supplying nutrients from yolk sac and maternal blood to developing fetus by facilitating transport of glycerol in addition to water, and its implication for the fetal growth in utero.