Deletion of Cdh-16 Ksp-cadherin leads to a developmental delay in the ability to maximally concentrate urine in mouse

2021 ◽  
Author(s):  
R. Brent Thomson ◽  
Diane W. Dynia ◽  
Sarah Burlein ◽  
Benjamin Thomson ◽  
Carmen J Booth ◽  
...  
Keyword(s):  
Developmental Delay ◽  
Kidney Development ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Critical Role ◽  
Osmotic Gradient ◽  
Mammalian Kidney ◽  
Concentrate Urine ◽  
Urinary Concentrating Ability ◽  
E Cadherin

Ksp-cadherin (Cadherin-16) is an atypical member of the cadherin superfamily of cell adhesion molecules that is ubiquitously expressed on the basolateral membrane of epithelial cells lining the nephron and the collecting system of the mammalian kidney. The principal aim of the present study was to determine if Ksp-cadherin played a critical role in the development and maintenance of the adult mammalian kidney by generating and evaluating a mouse line deficient in Ksp-cadherin. Ksp-null mutant animals were viable and fertile, and kidneys from both neonates and adults showed no evidence of structural abnormalities. Immunolocalization and Western analyses of Na/K-ATPase and E-cadherin indicated that Ksp-cadherin is not essential for either the genesis or maintenance of the polarized tubular epithelial phenotype. Moreover, E-cadherin expression was not altered to compensate for Ksp-cadherin loss. Plasma electrolytes, total CO2, BUN, and creatinine levels were also unaffected by Ksp-cadherin deficiency. However, a subtle but significant developmental delay in the ability to maximally concentrate urine was detected in Ksp-null mice. Expression analysis of the principal proteins involved in the generation of the cortico-medullary osmotic gradient and the resultant movement of water identified misexpression of Aquaporin-2 in the inner medullary collecting duct as the possible cause for the inability of young adult Ksp-cadherin deficient animals to maximally concentrate their urine. In conclusion, Ksp-cadherin is not required for normal kidney development but its absence leads to a developmental delay in maximal urinary concentrating ability.

Nephrogenic Diabetes Insipidus

1996 ◽  
Vol 17 (4) ◽  
pp. 145-146
Author(s):  
Corrine Benchimol
Keyword(s):  
Diabetes Insipidus ◽  
Nephrogenic Diabetes Insipidus ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Duct Cell ◽  
Cell Binding ◽  
Luminal Membrane ◽  
Concentrate Urine ◽  
V2 Receptor ◽  
Final Effect

Nephrogenic diabetes insipidus (NDI) is a disorder, either congenital or acquired, in which antidiuretic hormone (ADH) secretion is normal, but the ability to concentrate urine is reduced because of insensitivity of the collecting tubule to ADH. The antidiuretic action of arginine vasopressin requires binding of the hormone to the renal type V2 receptor on the basolateral membrane of the collecting duct principal cell. Binding results in activation of adenylate cyclase, generation of cAMP, and increased reabsorption of water across the apical membrane of the renal collecting duct cell. The defect in NDI may be located at any of the steps from binding of vasopressin to the final effect of the hormone on the luminal membrane.

scholarly journals Vasopressin inhibits apoptosis in renal collecting duct cells

2013 ◽  
Vol 304 (2) ◽  
pp. F177-F188 ◽  
Author(s):  
R. Lance Miller ◽  
Pablo C. Sandoval ◽  
Trairak Pisitkun ◽  
Mark A. Knepper ◽  
Jason D. Hoffert
Keyword(s):  
Arginine Vasopressin ◽  
Collecting Duct ◽  
Critical Role ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Cortical Collecting Duct ◽  
Caspase Cleavage ◽  
Mammalian Kidney ◽  
Duct Cells ◽  
V2 Receptor ◽  
Collecting Duct Cells

The peptide hormone arginine vasopressin (AVP) plays a critical role in regulating salt and water transport in the mammalian kidney. Recent studies have also demonstrated that AVP can promote cell survival in neuronal cells through V1 receptors. The current study addresses whether AVP can inhibit apoptosis in kidney collecting duct cells via V2 receptors and also explores the downstream signaling pathways regulating this phenomenon. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling analysis and caspase cleavage assays demonstrated that 1-desamino-8-d-arginine vasopressin (dDAVP) inhibited apoptosis induced by various agents (staurosporine, actinomycin D, and cycloheximide) in cultured mouse cortical collecting duct cells (mpkCCD). Incubation with dDAVP also inhibited apoptosis induced by the phosphatidylinositol 3-kinase (PI3K) pathway inhibitor LY294002, suggesting that the antiapoptotic effects of dDAVP are largely independent of PI3K signaling. The V2 receptor antagonist SR121463 completely abolished the antiapoptotic effects of dDAVP. In addition, incubation with 8-cpt-cAMP, a cell-permeable analog of cAMP, reproduced the antiapoptotic effects of dDAVP. Both dDAVP and 8-cpt-cAMP increased phosphorylation of proapoptotic Bcl-2 family members Bad and Bok. Bad phosphorylation at Ser-112 and Ser-155 is known to inhibit its proapoptotic activity. Preincubation with H89 blocked dDAVP-induced phosphorylation of both Bad and Bok, suggesting dependence on protein kinase A (PKA). This study provides evidence that AVP can inhibit apoptosis through the V2 receptor and downstream cAMP-mediated pathways in mammalian kidney. The antiapoptotic action of AVP may be relevant to a number of physiological and pathophysiological conditions including osmotic tolerance in the inner medulla, escape from AVP-induced antidiuresis, and polycystic kidney disease.

Renal expression of osmotically responsive cation channel TRPV4 is restricted to water-impermeant nephron segments

2004 ◽  
Vol 287 (1) ◽  
pp. F17-F24 ◽  
Author(s):  
Wei Tian ◽  
Michele Salanova ◽  
Hongshi Xu ◽  
Jessie N. Lindsley ◽  
Terry T. Oyama ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Rnase Protection Assay ◽  
Cation Channel ◽  
Osmotic Gradient ◽  
Thick Ascending Limb ◽  
Rnase Protection ◽  
Nephron Segments ◽  
Thin Limb

TRPV4, a nonselective cation channel of the transient receptor potential (TRP) family, is gated by hypotonicity. Expression of TRPV4 mRNA has been detected in the circumventricular organs of the brain responsible for sensing systemic tonicity and in the kidney distal convoluted tubule (DCT), among other sites. No analysis of TRPV4 expression at the protein level has been undertaken and no systematic analysis of expression of this channel has been reported in the kidney. Via RNAse protection assay and immunoblotting, abundant expression of TRPV4 was detected in the cortex, medulla, and papilla. The expression pattern of TRPV4 was characterized in both rat and mouse kidney, which revealed similar patterns of immunoreactivity. TRPV4 expression was absent from the proximal tubule (PT) and descending thin limb (DTL), whereas the strongest expression was observed in the ascending thin limb (ATL). The thick ascending limb (TAL) was strongly positive as was the DCT and connecting tubule. Importantly, the water-permeant cells of the macula densa were unstained. Moderate TRPV4 expression was noted in all collecting duct portions and in papillary epithelium; intercalated cells (type A) exhibited a particularly strong signal. In all positive segments, TRPV4 expression was concentrated at the basolateral membrane. Therefore, TRPV4 is expressed in only those nephron segments that are constitutively (i.e., ATL, TAL, and DCT) or conditionally (i.e., collecting duct) water impermeant and where generation of a substantial transcellular osmotic gradient could be expected. TRPV4 expression is absent from nephron segments exhibiting constitutive water permeability and unregulated apical aquaporin expression (i.e., PT and DTL). These data, although circumstantial, are consistent with a role for TRPV4 in the response to anisotonicity in the mammalian kidney.

scholarly journals Architecture of interstitial nodal spaces in the rodent renal inner medulla

2013 ◽  
Vol 305 (5) ◽  
pp. F745-F752 ◽  
Author(s):  
Rebecca L. Gilbert ◽  
Thomas L. Pannabecker
Keyword(s):  
Collecting Duct ◽  
Critical Role ◽  
Wistar Rat ◽  
Osmotic Gradient ◽  
Number Density ◽  
Strong Argument ◽  
Kangaroo Rat ◽  
Vasa Recta ◽  
Renal Inner Medulla ◽  
Abundant Supply

Every collecting duct (CD) of the rat inner medulla is uniformly surrounded by about four abutting ascending vasa recta (AVR) running parallel to it. One or two ascending thin limbs (ATLs) lie between and parallel to each abutting AVR pair, opposite the CD. These structures form boundaries of axially running interstitial compartments. Viewed in transverse sections, these compartments appear as four interstitial nodal spaces (INSs) positioned symmetrically around each CD. The axially running compartments are segmented by interstitial cells spaced at regular intervals. The pairing of ATLs and CDs bounded by an abundant supply of AVR carrying reabsorbed water, NaCl, and urea make a strong argument that the mixing of NaCl and urea within the INSs and countercurrent flows play a critical role in generating the inner medullary osmotic gradient. The results of this study fully support that hypothesis. We quantified interactions of all structures comprising INSs along the corticopapillary axis for two rodent species, the Munich-Wistar rat and the kangaroo rat. The results showed remarkable similarities in the configurations of INSs, suggesting that the structural arrangement of INSs is a highly conserved architecture that plays a fundamental role in renal function. The number density of INSs along the corticopapillary axis directly correlated with a loop population that declines exponentially with distance below the outer medullary-inner medullary boundary. The axial configurations were consistent with discrete association between near-bend loop segments and INSs and with upper loop segments lying distant from INSs.

Urinary concentrating ability in patients with Jk(a-b-) blood type who lack carrier-mediated urea transport.

1992 ◽  
Vol 2 (12) ◽  
pp. 1689-1696
Author(s):  
J M Sands ◽  
J J Gargus ◽  
O Fröhlich ◽  
R B Gunn ◽  
J P Kokko
Keyword(s):  
Animal Studies ◽  
Collecting Duct ◽  
Single Gene ◽  
Blood Type ◽  
Blood Group Antigens ◽  
Urea Transport ◽  
Urea Transporter ◽  
Concentrate Urine ◽  
Urinary Concentrating Ability ◽  
Urea Recycling

Water homeostasis is regulated in large part by the proper operation of the urinary concentrating mechanism. In the renal inner medulla, urea recycling from the inner medullary collecting duct to the inner medullary interstitium is thought to be essential for the production of a concentrated urine; however, it has not been possible to test this hypothesis in humans. Recently, a unique combination of genetic abnormalities has been described: absence of Kidd blood group antigens and absence of carrier-mediated urea transport in erythrocytes. Because animal studies indicate a similarity between urea transport in red blood cells and the nephron, it was postulated that patients without the Kidd antigen might lack facilitated urea transport in their kidneys. Hence, their ability to concentrate urine maximally was measured. Current models of nephron function would predict that in the complete absence of urea transport, the maximal concentrating ability would be around 800 to 900 mosM/kg H2O. Two homozygous patients had a moderate decrease in maximal concentrating ability (UosM,max = 819 mosM/kg H2O); a heterozygote also had some limitation. These studies raise the possibility that the erythrocyte urea transporter and the kidney urea transporter are encoded by a single gene (detected by the mutational loss of the Kidd antigen) and that a lack of facilitated urea transport impairs urea recycling in the kidney and, hence, maximal urinary concentrating ability.

Morphometric analysis of kidney hypertrophy in rats after chronic potassium depletion

1992 ◽  
Vol 262 (4) ◽  
pp. F656-F667 ◽  
Author(s):  
M. Elger ◽  
L. Bankir ◽  
W. Kriz
Keyword(s):  
Collecting Duct ◽  
Basolateral Membrane ◽  
Thick Ascending Limb ◽  
Membrane Area ◽  
Kidney Growth ◽  
Outer Stripe ◽  
Activity Of Enzymes ◽  
Medullary Collecting Duct ◽  
Urinary Concentrating Ability ◽  
K Depletion

Hypertrophic kidney growth in K depletion was analyzed morphometrically in rats fed a K-free diet for 18 days. K excretion decreased rapidly to less than 1% of control, creatinine clearance decreased, and urinary concentrating ability was impaired. Kidney weight in K-depleted rats was 30% higher than in controls. Growth of individual kidney zones was not uniform; hypertrophy of the inner stripe (IS) of the outer medulla was most prominent. Among tubules the most striking enlargement was seen in the outer medullary collecting duct (CD); hypertrophy and hyperplasia of both CD cells and intercalated (IC) cells occurred in the same proportion. In the IS, both luminal and basolateral membrane area per unit tubule length doubled in IC cells and increased 1.2- and 1.7-fold, respectively, in CD cells. Despite overall kidney growth, epithelial volume of thick ascending limb (TAL) per tubule length was unchanged in IS and cortex and only slightly increased in outer stripe. The increased membrane area of CD epithelium in the IS is consistent with previously reported increases in activity of enzymes involved in active reabsorption of K+ and Na+.

Multihormonal regulation of nephron epithelia: achieved through combinational mode?

1995 ◽  
Vol 269 (4) ◽  
pp. R739-R748 ◽  
Author(s):  
C. De Rouffignac
Keyword(s):  
Sodium Chloride ◽  
Hormonal Regulation ◽  
Biological Effects ◽  
Basolateral Membrane ◽  
Positive Interactions ◽  
Thick Ascending Limb ◽  
Transport Pathways ◽  
Receptor Complexes ◽  
Nephron Segment ◽  
Urinary Concentrating Ability

The kidney is the main organ regulating composition of body fluids. A considerable number of hormones control the activity of renal cells to maintain hydromineral equilibrium. It becomes more and more difficult to interpret this multihormonal control in terms of regulatory processes. To illustrate this complexity, the hormonal regulation of electrolyte transport in the nephron thick ascending limb is taken as an example. This nephron segment is largely responsible for two kidney functions: the urinary-concentrating ability (by its capacity to deliver hypertonic sodium chloride into the medullary interstitium) and regulation of magnesium excretion into final urine. Six hormones are presently identified as acting on the transport of both sodium chloride and magnesium ions in this nephron segment. Therefore, the pertinent question is how the thick ascending limb and, hence, the kidney, is capable of regulating water balance independently from magnesium balance. It is proposed that the hormones act in combination: circulating levels of the individual hormones acting on these cells may determine the configuration of the paracellular and transcellular transport pathways of the epithelium either in the “sodium” or “magnesium” mode. The configuration would depend on the distribution and activity of the receptor at the surface of the basolateral membrane in contact with the circulating hormones. This distribution along with stimulation of respective signal transduction pathways would lead to the final biological effects. It is already known that the distribution of cell receptors may vary according to factors such as age, nutritional variability, hormonal status, degree of desensitization of the receptors, etc. The modulation of hormonal responses would depend therefore on the degree of coupling of hormone-receptor complexes to different intracellular transduction pathways and on the resulting negative and/or positive interactions between these pathways.

scholarly journals iPSC technology-based regenerative medicine for kidney diseases

2021 ◽  
Author(s):  
Kenji Osafune
Keyword(s):  
Regenerative Medicine ◽  
Cell Therapy ◽  
Kidney Development ◽  
Disease Modeling ◽  
Kidney Diseases ◽  
Collecting Duct ◽  
Current Status ◽  
Renal Tubules ◽  
Discovery Research ◽  
Drug Discovery Research

AbstractWith few curative treatments for kidney diseases, increasing attention has been paid to regenerative medicine as a new therapeutic option. Recent progress in kidney regeneration using human-induced pluripotent stem cells (hiPSCs) is noteworthy. Based on the knowledge of kidney development, the directed differentiation of hiPSCs into two embryonic kidney progenitors, nephron progenitor cells (NPCs) and ureteric bud (UB), has been established, enabling the generation of nephron and collecting duct organoids. Furthermore, human kidney tissues can be generated from these hiPSC-derived progenitors, in which NPC-derived glomeruli and renal tubules and UB-derived collecting ducts are interconnected. The induced kidney tissues are further vascularized when transplanted into immunodeficient mice. In addition to the kidney reconstruction for use in transplantation, it has been demonstrated that cell therapy using hiPSC-derived NPCs ameliorates acute kidney injury (AKI) in mice. Disease modeling and drug discovery research using disease-specific hiPSCs has also been vigorously conducted for intractable kidney disorders, such as autosomal dominant polycystic kidney disease (ADPKD). In an attempt to address the complications associated with kidney diseases, hiPSC-derived erythropoietin (EPO)-producing cells were successfully generated to discover drugs and develop cell therapy for renal anemia. This review summarizes the current status and future perspectives of developmental biology of kidney and iPSC technology-based regenerative medicine for kidney diseases.

Water permeability of apical and basolateral cell membranes of rat inner medullary collecting duct

1990 ◽  
Vol 259 (6) ◽  
pp. F986-F999 ◽  
Author(s):  
B. Flamion ◽  
K. R. Spring
Keyword(s):  
Water Flow ◽  
Water Permeability ◽  
Cell Membranes ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Volume Regulatory Decrease ◽  
Water Permeation ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct

To quantify the pathways for water permeation through the kidney medulla, knowledge of the water permeability (Posmol) of individual cell membranes in inner medullary collecting duct (IMCD) is required. Therefore IMCD segments from the inner two thirds of inner medulla of Sprague-Dawley rats were perfused in vitro using a setup devised for rapid bath and luminal fluid exchanges (half time, t1/2, of 55 and 41 ms). Differential interference contrast microscopy, coupled to video recording, was used to measure volume and approximate surface areas of single cells. Volume and volume-to-surface area ratio of IMCD cells were strongly correlated with their position along the inner medullary axis. Transmembrane water flow (Jv) was measured in response to a variety of osmotic gradients (delta II) presented on either basolateral or luminal side of the cells. The linear relation between Jv and delta II yielded the cell membrane Posmol, which was then corrected for membrane infoldings. Basolateral membrane Posmol was 126 +/- 3 microns/s. Apical membrane Posmol rose from a basal value of 26 +/- 3 microns/s to 99 +/- 5 microns/s in presence of antidiuretic hormone (ADH). Because of amplification of basolateral membrane, the ADH-stimulated apical membrane remained rate-limiting for transcellular osmotic water flow, and the IMCD cell did not swell significantly. Calculated transcellular Posmol, expressed in terms of smooth luminal surface, was 64 microns/s without ADH and 207 microns/s with ADH. IMCD cells in anisosmotic media displayed almost complete volume regulatory decrease but only partial volume regulatory increase.

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