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Landon S King - One of the best experts on this subject based on the ideXlab platform.

  • A Novel Role for Aquaporin-5 in Enhancing Microtubule Organization and Stability
    PloS one, 2012
    Co-Authors: Venkataramana K Sidhaye, Eric Chau, Vasudha Srivastava, Srinivas Sirimalle, Chinmayee Balabhadrapatruni, Neil R. Aggarwal, Franco R. D'alessio, Douglas N. Robinson, Landon S King
    Abstract:

    Aquaporin-5 (AQP5) is a water-specific channel located on the apical surface of airway epithelial cells. In addition to regulating transcellular water permeability, AQP5 can regulate paracellular permeability, though the mechanisms by which this occurs have not been determined. Microtubules also regulate paracellular permeability. Here, we report that AQP5 promotes microtubule assembly and helps maintain the assembled microtubule steady state levels with slower turnover dynamics in cells. Specifically, reduced levels of AQP5 correlated with lower levels of assembled microtubules and decreased paracellular permeability. In contrast, overexpression of AQP5 increased assembly of microtubules, with evidence of increased MT stability, and promoted the formation of long straight microtubules in the apical domain of the epithelial cells. These findings indicate that AQP5-mediated regulation of microtubule dynamics modulates airway epithelial barrier properties and epithelial function.

  • Shear stress regulates Aquaporin-5 and airway epithelial barrier function
    Proceedings of the National Academy of Sciences of the United States of America, 2008
    Co-Authors: Venkataramana K Sidhaye, Kelly S Schweitzer, Michael J Caterina, Larissa A. Shimoda, Landon S King
    Abstract:

    As the interface with the outside world, the airway epithelial barrier is critical to lung defense. Because of respiratory efforts, the airways are exposed to shear stress; however, little is known regarding the effects of shear on epithelial function. We report that low-level shear stress enhances epithelial barrier function, an effect that requires serial activation of the transient receptor potential vanilloid (TRPV) 4 and L-type voltage-gated calcium channel (VGCC) and an increase in intracellular calcium. These changes lead to a selective decrease in Aquaporin-5 (AQP5) abundance because of protein internalization and degradation. To determine whether AQP5 plays a role in mediating the shear effects on paracellular permeability, we overexpressed hAQP5 in 16HBE cells, an airway epithelial cell line without endogenous AQP5. We found that AQP5 expression was needed for shear-induced barrier enhancement. These findings have direct relevance to the regulation of epithelial barrier function, membrane permeability, and water homeostasis in the respiratory epithelia.

  • transient receptor potential vanilloid 4 regulates Aquaporin 5 abundance under hypotonic conditions
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Venkataramana K Sidhaye, Ali D Guler, Kelly S Schweitzer, Franco R Dalessio, Michael J Caterina, Landon S King
    Abstract:

    Aquaporin-5 (AQP5) is expressed in epithelia of lung, cornea, and various secretory glands, sites where extracellular osmolality is known to fluctuate. Hypertonic Aquaporin (AQP) induction has been described, but little is known about the effects of a hypotonic environment on AQP abundance. We report that, when mouse lung epithelial cells were exposed to hypotonic medium, a dose-responsive decrease in AQP5 abundance was observed. Hypotonic reduction of AQP5 was blocked by ruthenium red, methanandamide, and miconazole, agents that inhibit the cation channel transient receptor potential vanilloid (TRPV) 4 present in lung epithelial cells. Several observations indicate that TRPV4 participates in hypotonic reduction of AQP5, including a requirement for extracellular calcium to achieve AQP5 reduction; an increase in intracellular calcium in mouse lung epithelial (MLE) cells after hypotonic stimulation; and reduction of AQP5 abundance after addition of the TRPV4 agonist 4α-Phorbol-12,13-didecanoate (4α-PDD). Similarly, addition of hypotonic PBS to mouse trachea in vivo decreased AQP5 within 1 h, an effect blocked by ruthenium red. To confirm a functional interaction, AQP5 was expressed in control or TRPV4-expressing human embryonic kidney (HEK) cells. Hypotonic reduction of AQP5 was observed only in the presence of TRPV4 and was blocked by ruthenium red. Combined with earlier studies, these observations indicate that AQP5 abundance is tightly regulated along a range of osmolalities and that AQP5 reduction by extracellular hypotonicity can be mediated by TRPV4. These findings have direct relevance to regulation of membrane water permeability and water homeostasis in epithelia of the lung and other organs.

  • cAMP has distinct acute and chronic effects on Aquaporin-5 in lung epithelial cells.
    The Journal of biological chemistry, 2004
    Co-Authors: Venkataramana K Sidhaye, Jason D. Hoffert, Landon S King
    Abstract:

    Aquaporin-5 (AQP5) is present on the apical membrane of epithelial cells in various secretory glands as well as on the apical membrane of the airway epithelium, airway submucosal glands, and type 1 pneumocytes, where it can participate in respiratory tract water homeostasis. We examined the effects of cAMP on AQP5 distribution and abundance. When AQP5-expressing mouse lung epithelial cells were treated with cAMP or the beta-adrenergic agonist terbutaline, a biphasic AQP5 response was observed. Short term (minutes) exposure to cAMP produced internalization of AQP5 off of the membrane and a decrease in protein abundance. Both of these responses were blocked by inhibition of protein kinase A and the decrease in abundance was blocked by chloroquine, indicating lysosome-mediated degradation. Sustained cAMP exposure (hours) produced an increase in membrane localization and increased abundance; these effects were also blocked by protein kinase A inhibition. The beta-adrenergic agonist terbutaline produced changes in AQP5 abundance in mouse trachea and lung, consistent with our findings in cultured epithelial cells. Purified AQP5 protein was phosphorylated by protein kinase A but not protein kinase C or casein kinase II, and Aquaporin-5 was phosphorylated in cultured cells after long term (but not short term) exposure to cAMP. These studies indicate that cAMP and beta-adrenergic agonists produce distinct short and long term effects on AQP5 distribution and abundance that may contribute to regulation of lung water homeostasis.

  • defective cellular trafficking of lacrimal gland Aquaporin 5 in sjogren s syndrome
    The Lancet, 2001
    Co-Authors: Landon S King, Peter Agre, Kazuo Tsubota, Shinichiro Hirai, Naruhiro Ishida
    Abstract:

    Dry eyes and dry mouth are clinical hallmarks of Sjogren's syndrome. We assessed the distribution of Aquaporin-5 (AQP5) in lacrimal gland biopsy samples. Healthy controls and patients with Mikulicz's disease or non-Sjogren's syndrome dry eye had the expected apical distribution of AQP5 in lacrimal acinar cells. By contrast, cytoplasmic AQP5 was seen in patients with Sjogren's syndrome. Sodium channel and sodium-potassium ATPase distributions were normal in all groups. These findings show a selective defect in lacrimal gland AQP5 trafficking in Sjogren's syndrome that might contribute to decreased lacrimation and dry eye in these patients.

Michael Adamzik - One of the best experts on this subject based on the ideXlab platform.

  • Aquaporin 5 -1364A/C Promoter Polymorphism Is Associated with Pulmonary Inflammation and Survival in Acute Respiratory Distress Syndrome
    Anesthesiology, 2019
    Co-Authors: Tim Rahmel, Katharina Rump, Jürgen Peters, Michael Adamzik
    Abstract:

    Editor’s PerspectiveWhat We Already Know about This TopicAcute respiratory distress syndrome is defined according to clinical criteria, but lack of precise characterization may contribute to negative trials and impede personalized care. Polymorphisms of Aquaporin-5, a key mediator of inflammation, m

  • Aquaporin 5 1364a c promoter polymorphism is associated with pulmonary inflammation and survival in acute respiratory distress syndrome
    Anesthesiology, 2019
    Co-Authors: Tim Rahmel, Katharina Rump, Jürgen Peters, Michael Adamzik
    Abstract:

    Editor’s PerspectiveWhat We Already Know about This TopicAcute respiratory distress syndrome is defined according to clinical criteria, but lack of precise characterization may contribute to negative trials and impede personalized care. Polymorphisms of Aquaporin-5, a key mediator of inflammation, m

  • The -1364A/C Aquaporin 5 Gene Promoter Polymorphism Is Not Associated with Menière’s Disease
    ISRN otolaryngology, 2012
    Co-Authors: Diana Arweiler-harbeck, Jürgen Peters, Freschta Saidi, Stephan Lang, Winfried Siffert, Michael Adamzik
    Abstract:

    Objective. Aquaporin 5 plays an important role in maintaining inner ear water and fluid homeostasis. Since the Aquaporin (AQP) 5 promoter-1364A/C polymorphism is associated with altered AQP5 expression and this could impact upon key mechanisms of Meniere's disease, we tested the hypothesis that genotypes of the AQP5 promoter-1364A/C polymorphism are associated with the incidences of Meniere's disease (MD), familial Meniere's disease (FMD), or endolymphatic hydrops (EH). Methods. With approval of the local ethics committee, DNA of 102 patients (39 with MD, 54 with FMD, and 9 with EH) and of 292-matched Caucasian controls was isolated from blood samples and genotyped for the AQP 5 promoter-1364A/C polymorphism. The χ2-test was applied to compare genotype distributions and allele frequencies between patients and controls. Results. Overall, genotype frequencies were not different between controls (AA 69%, AC 30%, CC 1%) and patients with MD AA: 65.7% (23 MD, 37 FMD, and 8 EH); AC: 23.5% (12 MD, 11 FMD, and 1 EH); CC: 3.9% (1 MD, 3 FMD, and 0 EH). However, subgroup analysis revealed the CC genotype to be more frequent in patients with FMD (5.9%) than in healthy controls (1%) (P = 0.042). Conclusions. Overall, genotypes of the -1364A/C AQP5 gene polymorphism are not associated with a significant increased risk for Meniere's disease.

Kazuo Hosoi - One of the best experts on this subject based on the ideXlab platform.

Christine Delporte - One of the best experts on this subject based on the ideXlab platform.

  • link between inflammation and Aquaporin 5 distribution in submandibular gland in sjogren s syndrome
    Oral Diseases, 2012
    Co-Authors: Muhammad Shahnawaz Soyfoo, A Konno, Nargis Bolaky, Js Oak, David A. Fruman, Charles Nicaise, M Takiguchi, Christine Delporte
    Abstract:

    Oral Diseases (2012) 18, 568–574 Objective:  To determine whether a link exists between inflammation and Aquaporin-5 distribution in submandibular glands from three animal models for Sjogren’s syndrome: IQI/JIC, r1ΔT/r2n and non-obese diabetic mice. Methods:  Mice of different ages were used. Inflammatory infiltrates were quantified using the focus score. Acinar Aquaporin-5 subcellular distribution was determined by immunohistochemistry and quantified using labelling indices. Results:  Minor inflammatory infiltrates were present in r1f/r2n mice. Massive inflammatory infiltrates and acinar destruction were observed in 24-week-old non-obese diabetic mice, 10-and 13-month-old IQI/JIC mice and some r1ΔT/r2n mice. Aquaporin-5 immunoreactivity was primarily apical in submandibular glands from 8- and 24-week-old Balb/C mice, 8-week-old non-obese diabetic mice, 2-, 4- and 7-month-old IQI/JIC mice and r1f/r2n mice. In contrast, decreased apical Aquaporin-5 labelling index with concomitant increased apical-basolateral, apical-cytoplasmic and/or apical-basolateral-cytoplasmic Aquaporin-5 labelling indices was observed in 24-week-old non-obese diabetic, 10- and 13-month-old IQI/JIC and r1ΔT/r2n mice with a focus score ≥ 1. Conclusions:  Altered Aquaporin-5 distribution in submandibular acinar cells from IQI/JIC, non-obese diabetic and r1ΔT/r2n mice with a focus score ≥ 1 appears to be concomitant to the presence of inflammatory infiltrates and acinar destruction.

  • Link between inflammation and Aquaporin‐5 distribution in submandibular gland in sjögren’s syndrome?
    Oral diseases, 2012
    Co-Authors: Muhammad Shahnawaz Soyfoo, A Konno, Nargis Bolaky, Js Oak, David A. Fruman, Charles Nicaise, M Takiguchi, Christine Delporte
    Abstract:

    Oral Diseases (2012) 18, 568–574 Objective:  To determine whether a link exists between inflammation and Aquaporin-5 distribution in submandibular glands from three animal models for Sjogren’s syndrome: IQI/JIC, r1ΔT/r2n and non-obese diabetic mice. Methods:  Mice of different ages were used. Inflammatory infiltrates were quantified using the focus score. Acinar Aquaporin-5 subcellular distribution was determined by immunohistochemistry and quantified using labelling indices. Results:  Minor inflammatory infiltrates were present in r1f/r2n mice. Massive inflammatory infiltrates and acinar destruction were observed in 24-week-old non-obese diabetic mice, 10-and 13-month-old IQI/JIC mice and some r1ΔT/r2n mice. Aquaporin-5 immunoreactivity was primarily apical in submandibular glands from 8- and 24-week-old Balb/C mice, 8-week-old non-obese diabetic mice, 2-, 4- and 7-month-old IQI/JIC mice and r1f/r2n mice. In contrast, decreased apical Aquaporin-5 labelling index with concomitant increased apical-basolateral, apical-cytoplasmic and/or apical-basolateral-cytoplasmic Aquaporin-5 labelling indices was observed in 24-week-old non-obese diabetic, 10- and 13-month-old IQI/JIC and r1ΔT/r2n mice with a focus score ≥ 1. Conclusions:  Altered Aquaporin-5 distribution in submandibular acinar cells from IQI/JIC, non-obese diabetic and r1ΔT/r2n mice with a focus score ≥ 1 appears to be concomitant to the presence of inflammatory infiltrates and acinar destruction.

  • Triplex-forming oligonucleotides can modulate Aquaporin-5 gene expression in epithelial cells.
    Antisense & nucleic acid drug development, 1997
    Co-Authors: Christine Delporte, Brian O'connell, Igor G. Panyutin, Olga A. Sedelnikova, C D Lillibridge, Bruce J. Baum
    Abstract:

    Triplex-forming oligonucleotides (TFOs) may provide a useful approach to decrease gene transcription in vivo. We have identified two sequences in the rat Aquaporin 5 (rAQP5) cDNA that are capable of forming a DNA triple helix. We designed four TFOs based on these sequences (a purine and a pyrimidine TFO per sequence). All four TFOs were able to bind to the rAQP5 cDNA at varying efficiencies in vitro as measured by using gel mobility shift assays. The TFOs were delivered to intact MDCK epithelial cells via adenovirus-polylysine complexes. Experiments with fluorescein-isothiocyanate-labeled oligonucleotides delivered in this way showed primarily a nuclear localization. Three of the four TFOs internalized by adenovirus-polylysine complexes were capable of decreasing rAQP5 expression in intact MDCK cells infected with a recombinant adenovirus encoding rAQP5. These data show that adenovirus-polylysine-TFO complexes can result in TFO delivery to the nucleus in intact epithelial cells and that TFOs may provide a useful way to selectively modulate rAQP5 gene expression.

  • Adenovirus-mediated Expression of Aquaporin-5 in Epithelial Cells
    The Journal of biological chemistry, 1996
    Co-Authors: Christine Delporte, Peter Agre, Brian O'connell, Indu S. Ambudkar, Bruce J. Baum
    Abstract:

    A recombinant adenovirus coding for rat Aquaporin-5 was constructed and plaque purified. The recombinant adenovirus (AdrAQP5) mediated the expression of Aquaporin-5 in rat and human salivary cell lines and in dog kidney cells in vitro as demonstrated by Northern blot and Western blot analyses, and by confocal microscopy after immunofluorescent labeling. In kidney cells, expression of the transgene was optimal if cells were infected at their basolateral surface, a phenomenon associated with the distribution of integrin receptors on these cells. The expressed Aquaporin-5 protein was functionally active because viral-mediated gene transfer resulted in a significant increase in the osmotically directed net fluid secretion rate across monolayers of kidney cells. AdrAQP5 should provide an efficient and useful means to impart facilitated water permeability to cells lacking such a pathway.

Yasuko Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • Aquaporin-5 water channel in lipid rafts of rat parotid glands.
    Biochimica et biophysica acta, 2006
    Co-Authors: Yasuko Ishikawa, Gota Cho, Zhenfang Yuan, Noriko Inoue, Yoshiko Nakae
    Abstract:

    Abstract Aquaporin-5 (AQP5), an apical plasma membrane (APM) water channel in salivary glands, lacrimal glands, and airway epithelium, has an important role in fluid secretion. The activation of M3 muscarinic acetylcholine receptors (mAChRs) or α1-adrenoceptors on the salivary glands induces salivary fluid secretion. AQP5 localizes in lipid rafts and activation of the M3 mAChRs or α1-adrenoceptors induced its translocation together with the lipid rafts to the APM in the interlobular ducts of rat parotid glands. This review focuses on the mechanisms of AQP5 translocation together with lipid rafts to the APM in the interlobular duct cells of parotid glands of normal rats and the impairment of AQP5 translocation in diabetes and senescence.

  • Age-related Decreases in the Response of Aquaporin-5 to Acetylcholine in Rat Parotid Glands
    Journal of dental research, 2003
    Co-Authors: N. Inoue, Yasuko Ishikawa, Hirokazu Iida, Z. Yuan, H. Ishida
    Abstract:

    Aquaporin-5 (AQP5) is important in salivary fluid secretion in response to cholinergic and adrenergic stimuli in rat parotid glands. We hypothesized that expression and function of AQP5 might change with age. Acetylcholine and epinephrine induced increases in AQP5 levels in the apical plasma membranes of both young adult and senescent rats. The stimulatory effect of acetylcholine, but not that of epinephrine, on AQP5 levels in the apical plasma membranes of the cells decreased markedly during aging. The quinuclidine derivative, SNI-2011, induced a persistent increase in AQP5 levels in the apical plasma membrane in the cells of both these rats. The amounts of M3-muscarinic receptor and Gq proteins did not decrease during aging. The age-related alteration in the responsiveness of AQP5 in the cells to these stimuli might account for the concomitant changes in nitric oxide synthase activity. These results suggest that SNI-2011 might have therapeutic benefit for the treatment of age-related xerostomia.

  • α1-Adrenoceptor-Induced Trafficking of Aquaporin-5 to the Apical Plasma Membrane of Rat Parotid Cells
    Biochemical and biophysical research communications, 1999
    Co-Authors: Yasuko Ishikawa, Noriko Inoue, Mariusz T. Skowronski, Hajime Ishida
    Abstract:

    Abstract Incubation of rat parotid tissue with 10 μM epinephrine resulted in a transient and marked trafficking of Aquaporin-5 (AQP5) from intracellular membranes to the apical plasma membrane (APM) that was maximal at 1 min. This effect of epinephrine was mimicked by phenylephrine, but not by clonidine, dobutamine, or salbutamol, and it was inhibited by phentolamine, but not by propranolol. Furthermore, the epinephrine-induced trafficking of AQP5 was inhibited by phospholipase C inhibitor U73122 as well as dantrolene and TMB-8, both of which inhibit the release of Ca2+ from intracellular stores. Cytochalasin D and tubulozole-C also inhibited this action of epinephrine. These results indicate that epinephrine, acting at α1-adrenoceptors, induces the trafficking of AQP5 to the APM by triggering the release of Ca2+ from intracellular stores through inositol 1,4,5-trisphosphate and ryanodine receptors. In addition, the potent involvement of the cytoskeleton was shown in the epinephrine-induced trafficking of AQP5.