Aquaporins in the Kidney

Kwon, Tae‐Hwan; Nielsen, Jens Perch; Møller, Hanne B.; Fenton, Robert A.; Nielsen, Søren; Frøkiær, Jørgen

doi:10.1007/978-3-540-79885-9_5

Cited by 62 publications

(62 citation statements)

References 215 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This may be explained by the fact that L1CAM is a membrane glycoprotein normally expressed at the basolateral membrane of the collecting-duct epithelial cell, which with injury is translocated to the apical membrane (23,24). We studied other potentially important biomarkers, including AQP2, a water channel (25); E-cadherin, a cell adhesion molecule (8,9,26,27); and N-cadherin, another member of the cadherin family (9,28,29). Although the excretion of these candidate proteins was altered in our casepatients, they did not correlate with renal function or with a reduced GFR.…”

Section: Discussionmentioning

confidence: 83%

Urinary Biomarkers in Obstructive Nephropathy

Trnka

Ivanova

Hiatt

et al. 2012

Clinical Journal of the American Society of Nephrology

View full text Add to dashboard Cite

SummaryBackground and objectives Obstructive nephropathy is a leading cause of CKD in children. The assessment of severity of renal impairment and the prediction of which children will progress to renal failure are, however, challenging.Design, Setting, Participants, & Measurements This case-control study measured the urinary excretion of candidate biomarkers in 27 prevalent case-patients with posterior urethral valves (PUVs) and 20 age-matched controls, correlated their urinary concentration with GFR, and analyzed receiver-operating characteristic (ROC) curve and regression analyses to assess their performance as tests for low GFR.Results The median urinary protein-to-creatinine ratio was higher in children with PUV (45 g/mol; range, 5-361 g/mol) than in controls (7 g/mol; range, 3-43 g/mol) (P,0.01) and correlated inversely with renal function (r = 20.44; P,0.05). In whole urine, excretion of aquaporin-2 was significantly decreased, whereas that of TGFb and L1 cell adhesion molecule (L1CAM) was significantly increased. Whole-urine TGFb excretion correlated inversely with GFR (r = 20.53; P,0.05). As tests for low GFR, whole-urine TGFb, L1CAM, and urinary proteinto-creatinine ratio performed best, with areas under the ROC curves of 0.788, 0.795, and 0.814, respectively. By linear regression analysis, whole-urine TGFb, L1CAM, and urinary protein-to-creatinine ratio were associated with low GFR in the case-patients.Conclusions Candidate biomarkers of obstructive nephropathy can be readily measured in whole urine and in urine exosomes. In boys with PUV, these biomarkers correlate with GFR.

show abstract

Section: Discussionmentioning

confidence: 83%

Urinary Biomarkers in Obstructive Nephropathy

Trnka

Ivanova

Hiatt

et al. 2012

Clinical Journal of the American Society of Nephrology

View full text Add to dashboard Cite

show abstract

“…Aquaporin-2 (AQP2) is the key water channel protein expressed in the kidney connecting tubules and collecting ducts for arginine vasopressin (AVP)-mediated water reabsorption (5,10,12,20,22). Vasopressin V2-receptor (V2R)-mediated cAMP/PKA signaling has been shown to be a principal pathway for both AQP2 trafficking and protein expression via activation of G s ␣-mediated adenylyl cyclase activity.…”

mentioning

confidence: 99%

Tankyrase-mediated β-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells

Jung

Kim

Choi

et al. 2015

American Journal of Physiology-Renal Physiology

Self Cite

View full text Add to dashboard Cite

Nielsen S, Kwon TH. Tankyrase-mediated ␤-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells. Am J Physiol Renal Physiol 308: F473-F486, 2015. First published December 17, 2014 doi:10.1152/ajprenal.00052.2014.-Aquaporin-2 (AQP2) mediates arginine vasopressin (AVP)-induced water reabsorption in the kidney collecting duct. AVP regulates AQP2 expression primarily via Gs␣/cAMP/PKA signaling. Tankyrase, a member of the poly(ADP-ribose) polymerase family, is known to mediate Wnt/␤-catenin signaling-induced gene expression. We examined whether tankyrase plays a role in AVP-induced AQP2 regulation via ADP-ribosylation of G protein-␣ (G␣) and/or ␤-catenin-mediated transcription of AQP2. RT-PCR and immunoblotting analysis revealed the mRNA and protein expression of tankyrase in mouse kidney and mouse collecting duct mpkCCDc14 cells. dDAVP-induced AQP2 upregulation was attenuated in mpkCCDc14 cells under the tankyrase inhibition by XAV939 treatment or small interfering (si) RNA knockdown. Fluorescence resonance energy transfer image analysis, however, revealed that XAV939 treatment did not affect dDAVP-or forskolin-induced PKA activation. Inhibition of tankyrase decreased dDAVP-induced phosphorylation of ␤-catenin (S552) and nuclear translocation of phospho-␤-catenin. siRNA-mediated knockdown of ␤-catenin decreased forskolin-induced AQP2 transcription and dDAVP-induced AQP2 expression. Moreover, inhibition of phosphoinositide 3-kinase/Akt, which was associated with decreased nuclear translocation of ␤-catenin, diminished dDAVP-induced AQP2 upregulation, further indicating that ␤-catenin mediates AQP2 expression. Taken together, tankyrase plays a role in AVP-induced AQP2 regulation, which is likely via ␤-catenin-mediated transcription of AQP2, but not ADP-ribosylation of G␣. The results provide novel insights into vasopressin-mediated urine concentration and homeostasis of body water metabolism.aquaporin-2; ␤-catenin; collecting duct; tankyrase; vasopressin AQUAPORINS (AQPS) ARE WATER channel proteins that transport water molecules across the biomembrane. Aquaporin-2 (AQP2) is the key water channel protein expressed in the kidney connecting tubules and collecting ducts for arginine vasopressin (AVP)-mediated water reabsorption (5,10,12,20,22). Vasopressin V2-receptor (V2R)-mediated cAMP/PKA signaling has been shown to be a principal pathway for both AQP2 trafficking and protein expression via activation of G s ␣-mediated adenylyl cyclase activity. Increased intracellular cAMP concentration and activation of PKA phosphorylate cAMP-response element binding protein, which increases transcription of the AQP2 gene (41).The AVP-induced cAMP/PKA signaling pathway interacts with other signals, such as phosphoinositide pathways (19,31) and Wnt/␤-catenin signaling (34). However, cross talk between AVP and Wnt/␤-catenin signaling in the kidney collecting ducts, particularly for the regulation of AVP-induced AQP2 expression, is unknown. Previous studies demonstrated that AVP-mediate...

show abstract

“…The protons pumped into the lumen are used to drive water to be excreted from the plasma into the collecting duct lumen via aquaporins through the neighboring principal cells. Regulation of water permeability is modified via regulated trafficking of vesicles carrying aquaporin to the plasma membrane (Kwon et al 2009;Nedvetsky et al 2009). Loss of either collecting duct aquaporin or V-ATPase function causes renal tubular acidosis and osteopetrosis (Borthwick and Karet 2002).…”

Section: Osmoregulatory Function Of the Excretory Systemmentioning

confidence: 99%

The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity

Sundaram

Buechner

2016

Genetics

View full text Add to dashboard Cite

The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal's life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes.KEYWORDS Caenorhabditis elegans; tubulogenesis; excretory-secretory system; WormBook

show abstract

Aquaporins in the Kidney

Cited by 62 publications

References 215 publications

Urinary Biomarkers in Obstructive Nephropathy

Urinary Biomarkers in Obstructive Nephropathy

Tankyrase-mediated β-catenin activity regulates vasopressin-induced AQP2 expression in kidney collecting duct mpkCCDc14 cells

The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity

Contact Info

Product

Resources

About