β1-Integrin is required for kidney collecting duct morphogenesis and maintenance of renal function

Deletion of integrin-β1 ( Itgb1) in the kidney collecting system led to progressive renal dysfunction and polyuria. The defect in the concentrating ability of the kidney was concomitant with decreased medullary collecting duct expression of aquaporin-2 and arginine vasopressin receptor 2, while histological examination revealed hypoplastic renal medullary collecting ducts characterized by increased apoptosis, ectasia and cyst formation. In addition, a range of defects from small kidneys with cysts and dilated tubules to bilateral renal agenesis was observed. This was likely due to altered growth and branching morphogenesis of the ureteric bud (the progenitor tissue of the renal collecting system), despite the apparent ability of the ureteric bud-derived cells to induce differentiation of the metanephric mesenchyme. These data not only support a role for Itgb1 in the development of the renal collecting system but also raise the possibility that Itgb1 links morphogenesis to terminal differentiation and ultimately collecting duct function and/or maintenance.

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Proteoglycans are required for maintenance of Wnt-11 expression in the ureter tips

Development ◽

10.1242/dev.122.11.3627 ◽

1996 ◽

Vol 122 (11) ◽

pp. 3627-3637 ◽

Cited By ~ 19

Author(s):

A. Kispert ◽

S. Vainio ◽

L. Shen ◽

D.H. Rowitch ◽

A.P. McMahon

Keyword(s):

Collecting Duct ◽

Expression Patterns ◽

Branching Morphogenesis ◽

Proteoglycan Synthesis ◽

Metanephric Mesenchyme ◽

Ureteric Bud ◽

Metanephric Kidney ◽

Specific Factors ◽

Collecting Duct Epithelium ◽

Metanephric Blastema

Development of the metanephric kidney requires the concerted interaction of two tissues, the epithelium of the ureteric duct and the metanephric mesenchyme. Signals from the ureter induce the metanephric mesenchyme to condense and proliferate around the ureter tip, reciprocal signals from the mesenchyme induce the ureter tip to grow and to branch. Wnt genes encode secreted glycoproteins, which are candidate mediators of these signaling events. We have identified three Wnt genes with specific, non-overlapping expression patterns in the metanephric kidney, Wnt-4, Wnt-7b and Wnt-11. Wnt-4 is expressed in the condensing mesenchyme and the comma- and S-shaped bodies. Wnt-7b is expressed in the collecting duct epithelium from 13.5 days post coitum onward. Wnt-1l is first expressed in the nephric duct adjacent to the metanephric blastema prior to the outgrowth of the ureteric bud. Wnt-l1 expression in Danforth's short-tail mice suggests that signaling from the mesenchyme may regulate Wnt-ll activation. During metanephric development, Wnt-11 expression is confined to the tips of the branching ureter. Maintenance of this expression is independent of Wnt-4 signaling and mature mesenchymal elements in the kidney. Moreover, Wnt-ll expression is maintained in recombinants between ureter and lung mesenchyme suggesting that branching morphogenesis and maintenance of Wnt-ll expression are independent of metanephric mesenchyme-specific factors. Interference with proteoglycan synthesis leads to loss of Wnt-ll expression in the ureter tip. We suggest that Wnt-11 acts as an autocrine factor within the ureter epithelium and that its expression is regulated at least in part by proteoglycans.

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Evolution of gene expression patterns in a model of branching morphogenesis

AJP Renal Physiology ◽

10.1152/ajprenal.1999.277.4.f650 ◽

1999 ◽

Vol 277 (4) ◽

pp. F650-F663 ◽

Cited By ~ 9

Author(s):

Anna Pavlova ◽

Robert O. Stuart ◽

Martin Pohl ◽

Sanjay K. Nigam

Keyword(s):

Gene Expression ◽

Differential Expression ◽

Expression Patterns ◽

Branching Morphogenesis ◽

Computational Method ◽

Metanephric Mesenchyme ◽

Ureteric Bud ◽

Cdna Arrays ◽

Apoptotic Genes ◽

Collecting System

Branching morphogenesis of the ureteric bud in response to unknown signals from the metanephric mesenchyme gives rise to the urinary collecting system and, via inductive signals from the ureteric bud, to recruitment of nephrons from undifferentiated mesenchyme. An established cell culture model for this process employs cells of ureteric bud origin (UB) cultured in extracellular matrix and stimulated with conditioned media (BSN-CM) from a metanephric mesenchymal cell line (H. Sakurai, E. J. Barros, T. Tsukamoto, J. Barasch, and S. K. Nigam. Proc. Natl. Acad. Sci. USA 94: 6279–6284, 1997.). In the presence of BSN-CM, the UB cells form branching tubular structures reminiscent of the branching ureteric bud. The pattern of gene regulation in this model of branching morphogenesis of the kidney collecting system was investigated using high-density cDNA arrays. Software and analytical methods were developed for the quantification and clustering of genes. With the use of a computational method termed “vector analysis,” genes were clustered according to the direction and magnitude of differential expression in n-dimensional log-space. Changes in gene expression in response to the BSN-CM consisted primarily of differential expression of transcription factors with previously described roles in morphogenesis, downregulation of pro-apoptotic genes accompanied by upregulation of anti-apoptotic genes, and upregulation of a small group of secreted products including growth factors, cytokines, and extracellular proteinases. Changes in expression are discussed in the context of a general model for epithelial branching morphogenesis. In addition, the cDNA arrays were used to survey expression of epithelial markers and secreted factors in UB and BSN cells, confirming the largely epithelial character of the former and largely mesenchymal character of the later. Specific morphologies (cellular processes, branching multicellular cords, etc.) were shown to correlate with the expression of different, but overlapping, genomic subsets, suggesting differences in morphogenetic mechanisms at these various steps in the evolution of branching tubules.

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Generation of kidney ureteric bud and collecting duct organoids that recapitulate kidney branching morphogenesis

10.1101/2020.04.27.049031 ◽

2020 ◽

Author(s):

Zipeng Zeng ◽

Biao Huang ◽

Riana K. Parvez ◽

Yidan Li ◽

Jyunhao Chen ◽

...

Keyword(s):

Stem Cells ◽

Progenitor Cells ◽

Kidney Development ◽

De Novo ◽

Collecting Duct ◽

Branching Morphogenesis ◽

Ureteric Bud ◽

Primary Mouse ◽

Collecting System

AbstractKidney organoids model development and diseases of the nephron but not the contiguous epithelial network of the kidney’s collecting duct (CD) system. Here, we report the generation of an expandable, 3D branching ureteric bud (UB) organoid culture model that can be derived from primary UB progenitors from mouse and human fetal kidneys, or generated de novo from pluripotent human stem cells. UB organoids differentiate into CD organoids in vitro, with differentiated cell types adopting spatial assemblies reflective of the adult kidney collecting system. Aggregating 3D-cultured nephron progenitor cells with UB organoids in vitro results in a reiterative process of branching morphogenesis and nephron induction, similar to kidney development. Combining efficient gene editing with the UB organoid model will facilitate an enhanced understanding of development, regeneration and diseases of the mammalian collecting system.One sentence summaryCollecting duct organoids derived from primary mouse and human ureteric bud progenitor cells and human pluripotent stem cells provide an in vitro platform for genetic dissection of development, regeneration and diseases of the mammalian collecting system.

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The instructive role of metanephric mesenchyme in ureteric bud patterning, sculpting, and maturation and its potential ability to buffer ureteric bud branching defects

AJP Renal Physiology ◽

10.1152/ajprenal.00125.2009 ◽

2009 ◽

Vol 297 (5) ◽

pp. F1330-F1341 ◽

Cited By ~ 17

Author(s):

Mita M. Shah ◽

James B. Tee ◽

Tobias Meyer ◽

Catherine Meyer-Schwesinger ◽

Yohan Choi ◽

...

Keyword(s):

Collecting Duct ◽

Organic Anion ◽

Organic Anion Transporter ◽

Metanephric Mesenchyme ◽

Ureteric Bud ◽

Functional Maturation ◽

Anion Transporter ◽

Cellular Contact ◽

Collecting System

Kidney organogenesis depends on reciprocal interactions between the ureteric bud (UB) and the metanephric mesenchyme (MM) to form the UB-derived collecting system and MM-derived nephron. With the advent of in vitro systems, it is clear that UB branching can occur independently of MM contact; however, little has been done to detail the role of MM cellular contact in this process. Here, a model system in which the cultured isolated UB is recombined with uninduced MM is used to isolate the effects of the MM progenitor tissue on the development and maturation of the collecting system. By morphometrics, we demonstrate that cellular contact with the MM is required for vectorial elongation of stalks and tapering of luminal caliber of UB-derived tubules. Expression analysis of developmentally significant genes indicates the cocultured tissue is most similar to an embryonic day 19 ( E19) kidney. The likely major contributor to this is the functional maturation of the collecting duct and proximal nephron segments in the UB-induced MM, as measured by quantitative PCR, of the collecting duct-specific arginine vasopressin receptor and the nephron tubule segment-specific organic anion transporter OAT1, Na-Pi type 2 cotransporter, and Tamm-Horsfall protein gene expressions. However, expression of aquaporin-2 is upregulated similarly in isolated UB and cocultured tissue, suggesting that some aspects of functional maturation can occur independently of MM cellular contact. In addition to its sculpting effects, the MM normalized a “branchless” UB morphology induced by FGF7 or heregulin in isolated UB culture. The morphological changes induced by the MM were accompanied by a reassignment of GFRα1 (a receptor for GDNF) to tips. Such “quality control” by the MM of UB morphology may provide resiliency to the branching program. This may help to explain a number of knockout phenotypes in which branching and/or cystic defects are less impressive than expected. A second hit in the MM may thus be necessary to make these defects fully apparent.

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FGF-7 modulates ureteric bud growth and nephron number in the developing kidney

Development ◽

10.1242/dev.126.3.547 ◽

1999 ◽

Vol 126 (3) ◽

pp. 547-554 ◽

Cited By ~ 11

Author(s):

J. Qiao ◽

R. Uzzo ◽

T. Obara-Ishihara ◽

L. Degenstein ◽

E. Fuchs ◽

...

Keyword(s):

Expression Patterns ◽

Body Volume ◽

Metanephric Mesenchyme ◽

Nephron Number ◽

Wild Type ◽

Ureteric Bud ◽

Kidney Size ◽

Bud Growth ◽

Collecting System

The importance of proportioning kidney size to body volume was established by clinical studies which demonstrated that in-born defecits of nephron number predispose the kidney to disease. As the kidney develops, the expanding ureteric bud or renal collecting system induces surrounding metanephric mesenchyme to proliferate and differentiate into nephrons. Thus, it is likely that nephron number is related to ureteric bud growth. The expression patterns of mRNAs encoding Fibroblast Growth Factor-7 (FGF-7) and its high affinity receptor suggested that FGF-7 signaling may play a role in regulating ureteric bud growth. To test this hypothesis we examined kidneys from FGF-7-null and wild-type mice. Results of these studies demonstrate that the developing ureteric bud and mature collecting system of FGF-7-null kidneys is markedly smaller than wild type. Furthermore, morphometric analyses indicate that mature FGF-7-null kidneys have 30+/−6% fewer nephrons than wild-type kidneys. In vitro experiments demonstrate that elevated levels of FGF-7 augment ureteric bud growth and increase the number of nephrons that form in rodent metanephric kidney organ cultures. Collectively, these results demonstrate that FGF-7 levels modulate the extent of ureteric bud growth during development and the number of nephrons that eventually form in the kidney.

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The laminin-binding integrins regulate nuclear factor kappa-β-dependent epithelial cell polarity and inflammation

Journal of Cell Science ◽

10.1242/jcs.259161 ◽

2021 ◽

Author(s):

Eugenia M. Yazlovitskaya ◽

Erin Plosa ◽

Fabian Bock ◽

Olga M. Viquez ◽

Glenda Mernaugh ◽

...

Keyword(s):

Epithelial Cell ◽

Cell Polarity ◽

Collecting Duct ◽

Branching Morphogenesis ◽

Conditional Knockout ◽

Double Knockout ◽

Epithelial Cell Polarity ◽

Developing Kidney ◽

Α3 Integrin ◽

Collecting System

The main laminin (LM)-binding integrins α3β1, α6β1 and α6β4 are co-expressed in the developing kidney collecting duct (CD) system. We previously showed that deleting the integrin α3 or α6 subunit in the ureteric bud (UB), which gives rise to the kidney collecting system, caused either a mild or no branching morphogenesis phenotype, respectively. To determine whether these two integrin subunits co-operate in kidney CD development, we deleted α3 and α6 in the developing UB. The collecting system of the double knockout phenocopied the α3 integrin conditional knockout. However, with age the mice developed severe inflammation and fibrosis around the CDs resulting in kidney failure. Integrin α3α6 null CD epithelial cells showed increased secretion of pro-inflammatory cytokines and displayed mesenchymal characterisitcs causing loss of barrier function. These features resulted from increased NF-κB activity, which regulated the Snail/Slug transcription factors and their downstream targets. These data suggest that LM-binding integrins play a key role in the maintenance of kidney tubule epithelial cell polarity and decrease pro-inflammatory cytokine secretion by regulating NF-κB-dependent signaling.

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Adrenomedullin Inhibits Osmotic Water Permeability in Rat Inner Medullary Collecting Ducts

Cells ◽

10.3390/cells9122533 ◽

2020 ◽

Vol 9 (12) ◽

pp. 2533

Author(s):

Fuying Ma ◽

Guangping Chen ◽

Eva L. Rodriguez ◽

Janet D. Klein ◽

Jeff M. Sands ◽

...

Keyword(s):

Water Permeability ◽

Collecting Duct ◽

Osmotic Water Permeability ◽

Water Reabsorption ◽

Kinase C ◽

Osmotic Water ◽

Collecting Ducts ◽

Medullary Collecting Duct ◽

Camp Levels ◽

Reduced Water

Adrenomedullin (ADM) is a vasodilator that causes natriuresis and diuresis. However, the direct effect of ADM on osmotic water permeability in the rat inner medullary collecting duct (IMCD) has not been tested. We investigated whether ADM and its ADM receptor components (CRLR, RAMP2, and 3) are expressed in rat inner medulla (IM) and whether ADM regulates osmotic water permeability in isolated perfused rat IMCDs. The mRNAs of ADM, CRLR, and RAMP2 and 3 were detected in rat IM. Abundant protein of CRLR and RAMP3 were also seen but RAMP2 protein level was extremely low. Adding ADM (100 nM) to the bath significantly decreased osmotic water permeability. ADM significantly decreased aquaporin-2 (AQP2) phosphorylation at Serine 256 (pS256) and increased it at Serine 261 (pS261). ADM significantly increased cAMP levels in IM. However, inhibition of cAMP by SQ22536 further decreased ADM-attenuated osmotic water permeability. Stimulation of cAMP by roflumilast increased ADM-attenuated osmotic water permeability. Previous studies show that ADM also stimulates phospholipase C (PLC) pathways including protein kinase C (PKC) and cGMP. We tested whether PLC pathways regulate ADM-attenuated osmotic water permeability. Blockade of either PLC by U73122 or PKC by rottlerin significantly augmented the ADM-attenuated osmotic water permeability and promoted pS256-AQP2 but did change pS261-AQP2. Inhibition of cGMP by L-NAME did not change AQP2 phosphorylation. In conclusion, ADM primarily binds to the CRLR-RAMP3 receptor to initiate signaling pathways in the IM. ADM reduced water reabsorption through a PLC-pathway involving PKC. ADM-attenuated water reabsorption may be related to decreased trafficking of AQP2 to the plasma membrane. cAMP is not involved in ADM-attenuated osmotic water permeability.

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Electrolyte and fluid secretion by cultured human inner medullary collecting duct cells

AJP Renal Physiology ◽

10.1152/ajprenal.00165.2002 ◽

2002 ◽

Vol 283 (6) ◽

pp. F1337-F1350 ◽

Cited By ~ 27

Author(s):

Darren P. Wallace ◽

Marcy Christensen ◽

Gail Reif ◽

Franck Belibi ◽

Brantley Thrasher ◽

...

Keyword(s):

Fluid Transport ◽

Collecting Duct ◽

Short Circuit ◽

Short Circuit Current ◽

Fluid Secretion ◽

Transport Studies ◽

Collecting Ducts ◽

Collecting Duct Cells ◽

Medullary Collecting Duct

Inner medullary collecting ducts (IMCD) are the final nephron segments through which urine flows. To investigate epithelial ion transport in human IMCD, we established primary cell cultures from initial (hIMCDi) and terminal (hIMCDt) inner medullary regions of human kidneys. AVP, PGE2, and forskolin increased cAMP in both hIMCDi and hIMCDt cells. The effects of AVP and PGE2 were greatest in hIMCDi; however, forskolin increased cAMP to the same extent in hIMCDi and hIMCDt. Basal short-circuit current ( I SC) of hIMCDi monolayers was 1.4 ± 0.5 μA/cm2 and was inhibited by benzamil, a Na+ channel blocker. 8-Bromo-cAMP, AVP, PGE2, and forskolin increased I SC; the current was reduced by blocking PKA, apical Cl− channels, basolateral NKCC1 (a Na+-K+-2Cl−cotransporter), and basolateral Cl−/HCO[Formula: see text]exchangers. In fluid transport studies, hIMCDi monolayers absorbed fluid in the basal state and forskolin reversed net fluid transport to secretion. In hIMCDt monolayers, basal current was not different from zero and cAMP had no effect on I SC. We conclude that AVP and PGE2stimulate cAMP-dependent Cl− secretion by hIMCDi cells, but not hIMCDt cells, in vitro. We suggest that salt secretion at specialized sites along human collecting ducts may be important in the formation of the final urine.

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Differential expression of collagen- and laminin-binding integrins mediates ureteric bud and inner medullary collecting duct cell tubulogenesis

AJP Renal Physiology ◽

10.1152/ajprenal.00015.2004 ◽

2004 ◽

Vol 287 (4) ◽

pp. F602-F611 ◽

Cited By ~ 45

Author(s):

Dong Chen ◽

Richard Roberts ◽

Martin Pohl ◽

Sanjay Nigam ◽

Jordan Kreidberg ◽

...

Keyword(s):

Collecting Duct ◽

Branching Morphogenesis ◽

Integrin Subunit ◽

Integrin Expression ◽

Dependent Manner ◽

Ureteric Bud ◽

Laminin Receptors ◽

Temporal And Spatial

Inner medullary collecting ducts (IMCD) are terminally differentiated structures derived from the ureteric bud (UB). UB development is mediated by changes in the temporal and spatial expression of integrins and their respective ligands. We demonstrate both in vivo and in vitro that the UB expresses predominantly laminin receptors (α3β1-, α6β1-, and α6β4-integrins), whereas the IMCD expresses both collagen (α1β1- and α2β1-integrins) and laminin receptors. Cells derived from the IMCD, but not the UB, undergo tubulogenesis in collagen-I (CI) gels in an α1β1- and α2β1-dependent manner. UB cells transfected with the α2-integrin subunit undergo tubulogenesis in CI, suggesting that collagen receptors are required for branching morphogenesis in CI. In contrast, both UB and IMCD cells undergo tubulogenesis in CI/Matrigel gels. UB cells primarily utilize α3β1- and α6-integrins, whereas IMCD cells mainly employ α1β1 for this process. These results demonstrate a switch in integrin expression from primarily laminin receptors in the early UB to both collagen and laminin receptors in the mature IMCD, which has functional consequences for branching morphogenesis in three-dimensional cell culture models. This suggests that temporal and spatial changes in integrin expression could help organize the pattern of branching morphogenesis of the developing collecting system in vivo.

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Increased collecting duct urea transporter expression in Dahl salt-sensitive rats

AJP Renal Physiology ◽

10.1152/ajprenal.00073.2003 ◽

2003 ◽

Vol 285 (1) ◽

pp. F143-F151 ◽

Cited By ~ 16

Author(s):

Robert A. Fenton ◽

Chung-Lin Chou ◽

Shana Ageloff ◽

William Brandt ◽

John B. Stokes ◽

...

Keyword(s):

Collecting Duct ◽

Hydroxysteroid Dehydrogenase ◽

Plasma Corticosterone ◽

Urea Transporter ◽

Rt Pcr ◽

Collecting Ducts ◽

Medullary Collecting Duct ◽

Transporter Expression ◽

Solute Transporter

Because abnormalities of inner medullary function have been proposed in Dahl salt-sensitive (DS) rats vs. salt-resistant (DR) rats, we performed transporter profiling by semiquantitative immunoblotting to determine whether specific solute transporter abundances are altered in inner medullas of DS rats vs. DR rats. Although none of the expressed Na transporters were upregulated in the inner medullas of DS rats compared with DR rats, there were marked increases in the protein abundances of the collecting duct urea transporters UT-A1 (to 212% of DR) and UT-A3 (to 223% of DR). These differences were confirmed by immunocytochemistry. Quantitative real-time RT-PCR showed higher mRNA abundance in DS rats for both UT-A1 (to 256% of DR) and UT-A3 (to 210% of DR). In isolated, perfused inner medullary collecting ducts, urea permeability was significantly greater in DS rats. Because both UT-A1 and UT-A3 are transcriptionally regulated by glucocorticoids, we measured both plasma corticosterone levels and inner medullary 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) abundances. Although the plasma corticosterone concentrations were not different between DS and DR rats, immunoblotting and immunocytochemistry revealed a marked elevation of 11β-HSD2 abundance in DS rats. Consistent with the view that an elevated 11β-HSD2 level is responsible for increased urea transporter expression in the inner medullary collecting duct, administration of the 11β-HSD2 inhibitor carbenoxolone to DS rats decreased the abundances of UT-A1 and UT-A3 to levels similar to those seen in DR rats.

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