scholarly journals Nephrogenic diabetes insipidus in mice caused by deleting COOH-terminal tail of aquaporin-2

2007 ◽  
Vol 292 (5) ◽  
pp. F1334-F1344 ◽  
Author(s):  
Peijun P. Shi ◽  
Xiao R. Cao ◽  
Jing Qu ◽  
Ken A. Volk ◽  
Patricia Kirby ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Hormonal Regulation ◽  
Nephrogenic Diabetes Insipidus ◽  
Mdck Cells ◽  
Collecting Duct ◽  
Phosphorylation Site ◽  
Water Channel ◽  
Urine Osmolality ◽  
Functional Expression ◽  
Aquaporin 2

In mammals, the hormonal regulation of water homeostasis is mediated by the aquaporin-2 water channel (Aqp2) of the collecting duct (CD). Vasopressin induces redistribution of Aqp2 from intracellular vesicles to the apical membrane of CD principal cells, accompanied by increased water permeability. Mutations of AQP2 gene in humans cause both recessive and dominant nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin. In this study, we generated a line of mice with the distal COOH-terminal tail of the Aqp2 deleted ( Aqp2Δ 230), including the protein kinase A phosphorylation site (S256), but still retaining the putative apical localization signal (221–229) at the COOH-terminal. Mice heterozygous for the truncation appear normal. Homozygotes are viable to adulthood, with reduced urine concentrating capacity, increased urine output, decreased urine osmolality, and increased daily water consumption. Desmopressin increased urine osmolality in wild-type mice but had no effect on Aqp2Δ 230/Δ 230 mice. Kidneys from affected mice showed CD and pelvis dilatation and papillary atrophy. By immunohistochemical and immunoblot analyses using antibody against the NH2-terminal region of the protein Aqp2Δ 230/Δ 230 mice had a markedly reduced protein abundance. Expression of the truncated protein in MDCK cells was consistent with a small amount of functional expression but no stimulation. Thus we have generated a mouse model of NDI that may be useful in studying the physiology and potential therapy of this disease.

scholarly journals Novel Treatment for Lithium-Induced Nephrogenic Diabetes Insipidus Rat Model Using the Sendai-Virus Vector Carrying Aquaporin 2 Gene

Endocrinology ◽  
2008 ◽  
Vol 149 (11) ◽  
pp. 5803-5810 ◽  
Author(s):  
Hidetaka Suga ◽  
Hiroshi Nagasaki ◽  
Taka-aki Kondo ◽  
Yoshiki Okajima ◽  
Chizuko Suzuki ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Nephrogenic Diabetes Insipidus ◽  
Sendai Virus ◽  
Collecting Duct ◽  
Water Channel ◽  
Vector System ◽  
Aquaporin 2 ◽  
Chronic Disorder ◽  
Life Threatening ◽  
Aqp2 Gene

Congenital nephrogenic diabetes insipidus (NDI) is a chronic disorder involving polyuria and polydipsia that results from unresponsiveness of the renal collecting ducts to the antidiuretic hormone vasopressin. Either of the genetic defects in vasopressin V2 receptor or the water channel aquaporin 2 (AQP2) cause the disease, which interfere the water reabsorption at the epithelium of the collecting duct. An unconscious state including a perioperative situation can be life threatening because of the difficulty to regulate their water balance. The Sendai virus (SeV) vector system deleting fusion protein (F) gene (SeV/ΔF) is considered most suitable because of the short replication cycle and nontransmissible character. An animal model for NDI with reduced AQP2 by lithium chloride was used to develop the therapy. When the SeV/ΔF vector carrying a human AQP2 gene (AQP2-SeV/ΔF) was administered retrogradely via ureter to renal pelvis, AQP2 was expressed in the renal collecting duct to reduce urine output and water intake by up to 40%. In combination with the retorograde administration to pelvis, this system could be the cornerstone for the applicable therapies on not only NDI patients but also other diseases associate with the medullary collecting duct.

scholarly journals Molecular Characterization of an Aquaporin−2 Mutation Causing Nephrogenic Diabetes Insipidus

2021 ◽  
Vol 12 ◽  
Author(s):  
Qian Li ◽  
Bichao Lu ◽  
Jia Yang ◽  
Chao Li ◽  
Yanchun Li ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Nephrogenic Diabetes Insipidus ◽  
Mdck Cells ◽  
Critical Role ◽  
Water Channel ◽  
Pathogenic Mechanism ◽  
Aquaporin 2 ◽  
Plasmid Transfection ◽  
Α Helix

The aquaporin 2 (AQP2) plays a critical role in water reabsorption to maintain water homeostasis. AQP2 mutation leads to nephrogenic diabetes insipidus (NDI), characterized by polyuria, polydipsia, and hypernatremia. We previously reported that a novel AQP2 mutation (G215S) caused NDI in a boy. In this study, we aimed to elucidate the cell biological consequences of this mutation on AQP2 function and clarify the molecular pathogenic mechanism for NDI in this patient. First, we analyzed AQP2 expression in Madin-Darby canine kidney (MDCK) cells by AQP2-G215S or AQP2-WT plasmid transfection and found significantly decreased AQP2-G215S expression in cytoplasmic membrane compared with AQP2-WT, independent of forskolin treatment. Further, we found co-localization of endoplasmic reticulum (ER) marker (Calnexin) with AQP2-G215S rather than AQP2-WT in MDCK cells by immunocytochemistry. The functional analysis showed that MDCK cells transfected with AQP2-G215S displayed reduced water permeability compared with AQP2-WT. Visualization of AQP2 structure implied that AQP2-G215S mutation might interrupt the folding of the sixth transmembrane α-helix and/or the packing of α-helices, resulting in the misfolding of monomer and further impaired formation of tetramer. Taken together, these findings suggested that AQP2-G215S was misfolded and retained in the ER and could not be translocated to the apical membrane to function as a water channel, which revealed the molecular pathogenic mechanism of AQP2-G215S mutation and explained for the phenotype of NDI in this patient.

scholarly journals Cell biological aspects of the vasopressin type-2 receptor and aquaporin 2 water channel in nephrogenic diabetes insipidus

2006 ◽  
Vol 291 (2) ◽  
pp. F257-F270 ◽  
Author(s):  
Joris H. Robben ◽  
Nine V. A. M. Knoers ◽  
Peter M. T. Deen
Keyword(s):  
Diabetes Insipidus ◽  
Nephrogenic Diabetes Insipidus ◽  
Current Knowledge ◽  
Collecting Duct ◽  
Water Channel ◽  
Water Reabsorption ◽  
Aquaporin 2 ◽  
Electrolyte Disturbances ◽  
Genes Encoding ◽  
V2 Receptor

In the renal collecting duct, water reabsorption is regulated by the antidiuretic hormone vasopressin (AVP). Binding of this hormone to the vasopressin V2 receptor (V2R) leads to insertion of aquaporin-2 (AQP2) water channels in the apical membrane, thereby allowing water reabsorption from the pro-urine to the interstitium. The disorder nephrogenic diabetes insipidus (NDI) is characterized by the kidney's inability to concentrate pro-urine in response to AVP, which is mostly acquired due to electrolyte disturbances or lithium therapy. Alternatively, NDI is inherited in an X-linked or autosomal fashion due to mutations in the genes encoding V2R or AQP2, respectively. This review describes the current knowledge of the cell biological causes of NDI and how these defects may explain the patients' phenotypes. Also, the increased understanding of these cellular defects in NDI has opened exciting initiatives in the development of novel therapies for NDI, which are extensively discussed in this review.

Mouse model of inducible nephrogenic diabetes insipidus produced by floxed aquaporin-2 gene deletion

2006 ◽  
Vol 291 (2) ◽  
pp. F465-F472 ◽  
Author(s):  
Baoxue Yang ◽  
Dan Zhao ◽  
Liman Qian ◽  
A. S. Verkman
Keyword(s):  
Mouse Model ◽  
Diabetes Insipidus ◽  
Urine Output ◽  
Nephrogenic Diabetes Insipidus ◽  
Gene Deletion ◽  
Collecting Duct ◽  
Urine Osmolality ◽  
Aquaporin 2 ◽  
Gene Excision ◽  
Aqp2 Gene

Transgenic mouse models of defective urinary concentrating ability produced by deletion of various membrane transport or receptor proteins, including aquaporin-2 (AQP2), are associated with neonatal mortality from polyuria. Here, we report an inducible mouse model of AQP2 gene deletion with severe polyuria in adult mice. LoxP sequences were inserted into introns 1 and 2 in the mouse AQP2 gene by homologous recombination in embryonic stem cells. Mating of germ-line AQP2-loxP mice with tamoxifen-inducible Cre-expressing mice produced offspring with inducible homozygous Cre-AQP2-loxP, which had a normal phenotype. Tamoxifen injections over 10 days resulted in AQP2 gene excision, with undetectable full-length AQP2 transcript in kidney and a >95% reduction in immunoreactive AQP2 protein. Urine osmolality decreased from ∼2,000 to <500 mosmol/kgH2O after 4–5 days, with urine output increasing from 2 to 25 ml/day. Urine osmolality did not increase after water deprivation. Interestingly, AQP3 protein expression in the collecting duct was increased by about fivefold after AQP2 gene excision. Mild renal damage was seen after 6 wk of polyuria, with collecting duct dilatation, yet normal creatinine clearance and serum chemistries. These results establish the first adult model of nephrogenic diabetes insipidus (NDI) caused by AQP2 deficiency, with daily urine output comparable to body weight, although remarkable preservation of renal function compared with non-inducible NDI models.

Downregulation of renal vasopressin V2 receptor and aquaporin-2 expression parallels age-associated defects in urine concentration

2004 ◽  
Vol 287 (4) ◽  
pp. F797-F805 ◽  
Author(s):  
Ying Tian ◽  
Ryota Serino ◽  
Joseph G. Verbalis
Keyword(s):  
Collecting Duct ◽  
Water Channel ◽  
Age Groups ◽  
Urine Osmolality ◽  
Brown Norway ◽  
Water Restriction ◽  
Water Excretion ◽  
F1 Hybrid ◽  
Young Rats ◽  
Aquaporin 2

Renal concentrating ability is known to be impaired with aging. The antidiuretic hormone AVP plays an important role in renal water excretion by regulating the membrane insertion and abundance of the water channel aquaporin-2 (AQP2); this effect is primarily mediated via the V2 subtype of the AVP receptor (V2R). This study evaluated the hypothesis that decreased renal sensitivity to AVP, with subsequent altered renal AQP2 expression, contributes to the reduced urinary concentrating ability with aging. Our results show that under baseline conditions, urine osmolality is significantly lower in aged Fischer 344 and Brown-Norway F1 hybrid (F344BN) rats despite equivalent plasma AVP concentrations as in young rats. Levels of kidney V2R mRNA expression and AQP2 abundances were also significantly decreased in aged F344BN rats, as was AQP2 immunostaining in collecting duct cells. In response to moderate water restriction, urine osmolality increased by significantly lesser amounts in aged F344BN rats compared with young rats despite similar increases in plasma AVP levels. Moderate water restriction induced equivalent relative increases in renal AQP2 abundances in all age groups but resulted in significantly lower abundances in total kidney AQP2 protein in aged compared with young F344BN rats. These results therefore demonstrate a functional impairment of renal concentrating ability in aged F344BN rats that is not due to impaired secretion of AVP but rather appears to be related to impaired responsiveness of the kidney to AVP that is secondary, at least in part, to a downregulation of renal V2R expression and AQP2 abundance.

scholarly journals Reversed polarized delivery of an aquaporin-2 mutant causes dominant nephrogenic diabetes insipidus

2003 ◽  
Vol 163 (5) ◽  
pp. 1099-1109 ◽  
Author(s):  
Erik-Jan Kamsteeg ◽  
Daniel G. Bichet ◽  
Irene B.M. Konings ◽  
Hubert Nivet ◽  
Michelle Lonergan ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Water Conservation ◽  
Nephrogenic Diabetes Insipidus ◽  
Water Channel ◽  
Apical Plasma Membrane ◽  
Apical Surface ◽  
Aquaporin 2 ◽  
Frame Shift ◽  
Polarized Delivery ◽  
Mutant Forms

Vasopressin regulates body water conservation by redistributing aquaporin-2 (AQP2) water channels from intracellular vesicles to the apical surface of renal collecting ducts, resulting in water reabsorption from urine. Mutations in AQP2 cause autosomal nephrogenic diabetes insipidus (NDI), a disease characterized by the inability to concentrate urine. Here, we report a frame-shift mutation in AQP2 causing dominant NDI. This AQP2 mutant is a functional water channel when expressed in Xenopus oocytes. However, expressed in polarized renal cells, it is misrouted to the basolateral instead of apical plasma membrane. Additionally, this mutant forms heterotetramers with wild-type AQP2 and redirects this complex to the basolateral surface. The frame shift induces a change in the COOH terminus of AQP2, creating both a leucine- and a tyrosine-based motif, which cause the reversed sorting of AQP2. Our data reveal a novel cellular phenotype in dominant NDI and show that dominance of basolateral sorting motifs in a mutant subunit can be the molecular basis for disease.

scholarly journals Aliskiren increases aquaporin-2 expression and attenuates lithium-induced nephrogenic diabetes insipidus

2017 ◽  
Vol 313 (4) ◽  
pp. F914-F925 ◽  
Author(s):  
Yu Lin ◽  
Tiezheng Zhang ◽  
Pinning Feng ◽  
Miaojuan Qiu ◽  
Qiaojuan Liu ◽  
...  
Keyword(s):  
Diabetes Insipidus ◽  
Nephrogenic Diabetes Insipidus ◽  
Collecting Duct ◽  
Renin Inhibitor ◽  
Protein Abundance ◽  
Aquaporin 2 ◽  
Direct Renin Inhibitor ◽  
Collecting Ducts ◽  
Dry Food ◽  
Concentrating Defect

The direct renin inhibitor aliskiren has been shown to be retained and persist in medullary collecting ducts even after treatment is discontinued, suggesting a new mechanism of action for this drug. The purpose of the present study was to investigate whether aliskiren regulates renal aquaporin expression in the collecting ducts and improves urinary concentrating defect induced by lithium in mice. The mice were fed with either normal chow or LiCl diet (40 mmol·kg dry food−1·day−1 for 4 days and 20 mmol·kg dry food−1·day−1 for the last 3 days) for 7 days. Some mice were intraperitoneally injected with aliskiren (50 mg·kg body wt−1·day−1 in saline). Aliskiren significantly increased protein abundance of aquaporin-2 (AQP2) in the kidney inner medulla in mice. In inner medulla collecting duct cell suspension, aliskiren markedly increased AQP2 and phosphorylated AQP2 at serine 256 (pS256-AQP2) protein abundance, which was significantly inhibited both by adenylyl cyclase inhibitor MDL-12330A and by PKA inhibitor H89, indicating an involvement of the cAMP-PKA signaling pathway in aliskiren-induced increased AQP2 expression. Aliskiren treatment improved urinary concentrating defect in lithium-treated mice and partially prevented the decrease of AQP2 and pS256-AQP2 protein abundance in the inner medulla of the kidney. In conclusion, the direct renin inhibitor aliskiren upregulates AQP2 protein expression in inner medullary collecting duct principal cells and prevents lithium-induced nephrogenic diabetes insipidus likely via cAMP-PKA pathways.

Dynamics of aquaporin-2 serine-261 phosphorylation in response to short-term vasopressin treatment in collecting duct

2007 ◽  
Vol 292 (2) ◽  
pp. F691-F700 ◽  
Author(s):  
Jason D. Hoffert ◽  
Jakob Nielsen ◽  
Ming-Jiun Yu ◽  
Trairak Pisitkun ◽  
Stephen M. Schleicher ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Phosphorylation Site ◽  
Water Channel ◽  
Distal Tubule ◽  
Immunohistochemical Analysis ◽  
Immunoblot Analysis ◽  
Dot Blot ◽  
Short Term ◽  
Antibody Recognition ◽  
Aquaporin 2

We recently identified a novel phosphorylation site, serine-261 (pS261), in the COOH-terminus of the vasopressin-regulated water channel, aquaporin-2 (AQP2). To address whether phosphorylation at this site is regulated by vasopressin, a rabbit polyclonal phospho-specific antibody was generated. Dot blot and immunoblot analysis demonstrated that this antibody specifically recognizes AQP2 phosphorylated at pS261, and that phosphorylation of S256 (pS256), a site already known to be regulated by vasopressin, does not interfere with antibody recognition. Immunohistochemical analysis revealed intense pS261 labeling of inner medullary collecting duct (IMCD) from wild-type mice, while sections from AQP2 knockout animals showed a general absence of labeling. AQP2 pS261 was present in principal cells of all mouse and rat distal tubule segments from the connecting tubule to the terminal IMCD. Co-immunolabeling of collecting duct with phospho-specific and total AQP2 antibodies revealed that pS261 and pS256 have distinct subcellular distributions. Levels of pS256 increased, while the amount of pS261 significantly decreased in freshly isolated rat IMCD samples incubated with 1 nM [deamino-Cys1,d-Arg8]vasopressin for 30 min. Similarly, based on immunohistochemical labeling, the amount of pS261 was reduced in all collecting duct segments of Brattleboro rats treated with [deamino-Cys1,d-Arg8]vasopressin for 2 h. This study reveals a reciprocal change in S256 and S261 phosphorylation in response to short-term vasopressin exposure, suggesting that these residues may serve distinct roles in regulation of AQP2 subcellular distribution and collecting duct water permeability.

Development of urinary concentrating capacity: role of aquaporin-2

1996 ◽  
Vol 271 (2) ◽  
pp. F461-F468 ◽  
Author(s):  
M. Yasui ◽  
D. Marples ◽  
R. Belusa ◽  
A. C. Eklof ◽  
G. Celsi ◽  
...  
Keyword(s):  
Single Injection ◽  
Collecting Duct ◽  
Water Channel ◽  
Urine Osmolality ◽  
Postnatal Life ◽  
Mrna Levels ◽  
Adult Rats ◽  
Protein Levels ◽  
Aquaporin 2 ◽  
Low Expression

The capacity to concentrate urine develops progressively during postnatal life in most mammalian species. Here we have examined whether low expression of the arginine vasopressin (AVP)-activated water channel aquaporin-2 (AQP-2) may be a limiting factor for the concentrating capacity in the infant rats. Urine osmolality in response to 24-h dehydration increased significantly from 10 to 40 days of age. The most rapid increase occurred during the weaning period, i.e., days 15-20. A similar developmental pattern was observed for AQP-2 mRNA levels in the renal medulla. AQP-2 protein levels also increased markedly from day 10 to 40. Immunohistochemistry revealed that AQP-2 was exclusively located in collecting duct principal cells both in infant and adult rats but that the signal was much weaker in infants. To further examine the relationship between urinary concentrating capacity and AQP-2 expression, we treated rats with a single injection of betamethasone, which is known to accelerate maturation in several organs. Twenty-four hours after treatment, there was an increase in urine osmolality, renal medullary AQP-2 mRNA, and AQP-2 protein levels in infant but not in adult rats. A single injection of a specific V2 agonist caused within 6 h significant increase of AQP-2 mRNA in both infant and adult. The expression of the mRNA of three other transporters involved in the concentrating process, medullary Na(+)-K(+)-ATPase alpha-subunit, Na-K-2Cl cotransporter, and epithelial chloride channel also increased during the weaning period and were upregulated by glucocorticoids. We conclude that there is a well-synchronized development of the many of the components that determine the concentrating capacity and that the low expression of AQP-2 is one of the limiting factors for low concentrating capacity in infants.

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