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Runeberg-Roos P, Piccinini E, Penttinen AM, Mätlik K, Heikkinen H, Kuure S, Bespalov MM, Peränen J, Garea-Rodríguez E, Fuchs E, Airavaara M, Kalkkinen N, Penn R, Saarma M. Developing therapeutically more efficient Neurturin variants for treatment of Parkinson's disease. Neurobiol Dis 2016; 96:335-345. [PMID: 27425888 DOI: 10.1016/j.nbd.2016.07.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/04/2016] [Accepted: 07/13/2016] [Indexed: 10/21/2022] Open
Abstract
In Parkinson's disease midbrain dopaminergic neurons degenerate and die. Oral medications and deep brain stimulation can relieve the initial symptoms, but the disease continues to progress. Growth factors that might support the survival, enhance the activity, or even regenerate degenerating dopamine neurons have been tried with mixed results in patients. As growth factors do not pass the blood-brain barrier, they have to be delivered intracranially. Therefore their efficient diffusion in brain tissue is of crucial importance. To improve the diffusion of the growth factor neurturin (NRTN), we modified its capacity to attach to heparan sulfates in the extracellular matrix. We present four new, biologically fully active variants with reduced heparin binding. Two of these variants are more stable than WT NRTN in vitro and diffuse better in rat brains. We also show that one of the NRTN variants diffuses better than its close homolog GDNF in monkey brains. The variant with the highest stability and widest diffusion regenerates dopamine fibers and improves the conditions of rats in a 6-hydroxydopamine model of Parkinson's disease more potently than GDNF, which previously showed modest efficacy in clinical trials. The new NRTN variants may help solve the major problem of inadequate distribution of NRTN in human brain tissue.
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Affiliation(s)
- Pia Runeberg-Roos
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland.
| | - Elisa Piccinini
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Anna-Maija Penttinen
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Kert Mätlik
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Hanna Heikkinen
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Satu Kuure
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Maxim M Bespalov
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Johan Peränen
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Enrique Garea-Rodríguez
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany
| | | | - Mikko Airavaara
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Nisse Kalkkinen
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
| | - Richard Penn
- CNS Therapeutics Inc., 332 Minnesota Street, Ste W1750, St. Paul, MN 55101, USA
| | - Mart Saarma
- Institute of Biotechnology, University of Helsinki, PB 56 (Viikinkaari 5D), FIN-00014, Finland
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2
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Lindström NO, Chang CH, Valerius MT, Hohenstein P, Davies JA. Node retraction during patterning of the urinary collecting duct system. J Anat 2014; 226:13-21. [PMID: 25292187 PMCID: PMC4299504 DOI: 10.1111/joa.12239] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 11/28/2022] Open
Abstract
This report presents a novel mechanism for remodelling a branched epithelial tree. The mouse renal collecting duct develops by growth and repeated branching of an initially unbranched ureteric bud: this mechanism initially produces an almost fractal form with young branches connected to the centre of the kidney via a sequence of nodes (branch points) distributed widely throughout the developing organ. The collecting ducts of a mature kidney have a different form: from the nephrons in the renal cortex, long, straight lengths of collecting duct run almost parallel to one another through the renal medulla, and open together to the renal pelvis. Here we present time-lapse studies of E11.5 kidneys growing in culture: after about 5 days, the collecting duct trees show evidence of ‘node retraction’, in which the node of a ‘Y’-shaped branch moves downwards, shortening the stalk of the ‘Y’, lengthening its arms and narrowing their divergence angle so that the ‘Y’ becomes a ‘V’. Computer simulation suggests that node retraction can transform a spread tree, like that of an early kidney, into one with long, almost-parallel medullary rays similar to those seen in a mature real kidney.
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3
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Lombaert IMA, Abrams SR, Li L, Eswarakumar VP, Sethi AJ, Witt RL, Hoffman MP. Combined KIT and FGFR2b signaling regulates epithelial progenitor expansion during organogenesis. Stem Cell Reports 2013; 1:604-19. [PMID: 24371813 PMCID: PMC3871401 DOI: 10.1016/j.stemcr.2013.10.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 11/14/2022] Open
Abstract
Organ formation and regeneration require epithelial progenitor expansion to engineer, maintain, and repair the branched tissue architecture. Identifying the mechanisms that control progenitor expansion will inform therapeutic organ (re)generation. Here, we discover that combined KIT and fibroblast growth factor receptor 2b (FGFR2b) signaling specifically increases distal progenitor expansion during salivary gland organogenesis. FGFR2b signaling upregulates the epithelial KIT pathway so that combined KIT/FGFR2b signaling, via separate AKT and mitogen-activated protein kinase (MAPK) pathways, amplifies FGFR2b-dependent transcription. Combined KIT/FGFR2b signaling selectively expands the number of KIT+K14+SOX10+ distal progenitors, and a genetic loss of KIT signaling depletes the distal progenitors but also unexpectedly depletes the K5+ proximal progenitors. This occurs because the distal progenitors produce neurotrophic factors that support gland innervation, which maintains the proximal progenitors. Furthermore, a rare population of KIT+FGFR2b+ cells is present in adult glands, in which KIT signaling also regulates epithelial-neuronal communication during homeostasis. Our findings provide a framework to direct regeneration of branched epithelial organs. Combined KIT and FGFR2b signaling amplifies FGFR2b-dependent transcription KIT/FGFR2b signaling during organogenesis expands distal KIT+ epithelial progenitors Distal progenitors communicate with proximal progenitors via the neuronal niche KIT+ progenitors maintain epithelial-neuronal communication during adult homeostasis
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Affiliation(s)
- Isabelle M A Lombaert
- Matrix and Morphogenesis Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shaun R Abrams
- Matrix and Morphogenesis Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Li Li
- Department of Orthopedics & Rehabilitation, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Veraragavan P Eswarakumar
- Department of Orthopedics & Rehabilitation, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Aditya J Sethi
- Developmental Mechanisms Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert L Witt
- Head & Neck Multidisciplinary Clinic, Helen F. Graham Cancer Center of Christiana Care, Newark, DE 19713, USA
| | - Matthew P Hoffman
- Matrix and Morphogenesis Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
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4
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Abstract
The mammalian ureter contains two main cell types: a multilayered water-tight epithelium called the urothelium, surrounded by smooth muscle layers that, by generating proximal to distal peristaltic waves, pump urine from the renal pelvis toward the urinary bladder. Here, we review the cellular mechanisms involved in the development of these tissues, and the molecules that control the process. We consider the relevance of these biologic findings for understanding the pathogenesis of human ureter malformations.
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Affiliation(s)
- Adrian S Woolf
- School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre and Manchester Children's Hospital, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
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5
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Abstract
Signaling by GDNF through the Ret receptor tyrosine kinase is required for the normal growth and morphogenesis of the ureteric bud (UB) during kidney development. Recent studies have sought to understand the precise role of Ret signaling in this process, and the specific responses of UB cells to GDNF. Surprisingly, the requirement for Gdnf and Ret was largely relieved by removing the negative regulator Spry1, revealing unexpected functional overlap between GDNF and FGF10. However, the kidneys that developed without Gdnf/Ret and Spry1 displayed significant branching abnormalities, suggesting a unique role for GDNF in fine-tuning UB branching. GDNF/Ret signaling alters patterns of gene expression in UB tip cells, and one critical event is upregulation of the ETS transcription factors Etv4 and Etv5. Mice lacking Etv4 and Etv5 fail to develop kidneys. Thus, these genes represent key components of a regulatory network downstream of Ret. Studies of chimeric embryos in which a subset of cells lack either Ret, Etv4/5 or Spry1 have revealed an important role for this pathway in cell movement. Ret signaling, via Etv4 and Etv5, promotes competitive cell rearrangements in the nephric duct, in which the cells with the highest level of Ret signaling preferentially migrate to form the first ureteric bud tip.
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Affiliation(s)
- Frank Costantini
- Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA.
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6
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Lee WC, Hough MT, Liu W, Ekiert R, Lindström NO, Hohenstein P, Davies JA. Dact2 is expressed in the developing ureteric bud/collecting duct system of the kidney and controls morphogenetic behavior of collecting duct cells. Am J Physiol Renal Physiol 2010; 299:F740-51. [DOI: 10.1152/ajprenal.00148.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The overall pattern of the developing kidney is set in large part by the developing ureteric bud/collecting duct system, and dysgenesis of this system accounts for a variety of clinically significant renal diseases. Understanding how the behavior of cells in the developing ureteric bud/collecting duct is controlled is therefore important to understanding the normal and abnormal kidney. Dact proteins have recently been identified as cytoplasmic regulators of intracellular signaling. Dact1 inhibits Wnt signaling, and Dact2 inhibits transforming growth factor (TGF)-β signaling. Here, we report that Dact2 is expressed in developing and adult mouse kidneys, specifically in the ureteric bud/collecting duct epithelium, a structure whose morphogenesis is controlled partially by TGF-β. When small interfering RNA is used to knock down Dact2 expression in collecting duct cells, they show some constitutive phospho-Smad2, undetectable in controls, and elevated phospho-Smad2 in response to TGF-β. They also show defective migration and, in a monolayer wound-healing assay, they fail to assemble a leading edge “cable” of actomyosin and advance instead as a disorganized mass of lamellipodium-bearing cells. This effect is seriously exacerbated by exogenous TGF-β, although control cells tolerate it well. In three-dimensional culture, Dact2 knockdown cells form cysts and branching tubules, but the outlines of the cysts made by knockdown cells are ragged rather than smooth and the branching tubules are decorated with many fine spikes not seen in controls. These data suggest Dact2 plays a role in regulating morphogenesis by renal collecting duct cells, probably by protecting cells from overly strong TGF-β pathway activation.
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Affiliation(s)
- Wen-Chin Lee
- Centre for Integrative Physiology, University of Edinburgh, and
| | | | - Weijia Liu
- Centre for Integrative Physiology, University of Edinburgh, and
| | - Robert Ekiert
- Centre for Integrative Physiology, University of Edinburgh, and
| | | | - Peter Hohenstein
- Medical Research Council Human Genetics Unit and Institute for Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Jamie A. Davies
- Centre for Integrative Physiology, University of Edinburgh, and
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7
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Michos O, Cebrian C, Hyink D, Grieshammer U, Williams L, D'Agati V, Licht JD, Martin GR, Costantini F. Kidney development in the absence of Gdnf and Spry1 requires Fgf10. PLoS Genet 2010; 6:e1000809. [PMID: 20084103 DOI: 10.1371/journal.pgen.1000809] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 12/10/2009] [Indexed: 11/19/2022] Open
Abstract
GDNF signaling through the Ret receptor tyrosine kinase (RTK) is required for ureteric bud (UB) branching morphogenesis during kidney development in mice and humans. Furthermore, many other mutant genes that cause renal agenesis exert their effects via the GDNF/RET pathway. Therefore, RET signaling is believed to play a central role in renal organogenesis. Here, we re-examine the extent to which the functions of Gdnf and Ret are unique, by seeking conditions in which a kidney can develop in their absence. We find that in the absence of the negative regulator Spry1, Gdnf, and Ret are no longer required for extensive kidney development. Gdnf−/−;Spry1−/− or Ret−/−;Spry1−/− double mutants develop large kidneys with normal ureters, highly branched collecting ducts, extensive nephrogenesis, and normal histoarchitecture. However, despite extensive branching, the UB displays alterations in branch spacing, angle, and frequency. UB branching in the absence of Gdnf and Spry1 requires Fgf10 (which normally plays a minor role), as removal of even one copy of Fgf10 in Gdnf−/−;Spry1−/− mutants causes a complete failure of ureter and kidney development. In contrast to Gdnf or Ret mutations, renal agenesis caused by concomitant lack of the transcription factors ETV4 and ETV5 is not rescued by removing Spry1, consistent with their role downstream of both RET and FGFRs. This shows that, for many aspects of renal development, the balance between positive signaling by RTKs and negative regulation of this signaling by SPRY1 is more critical than the specific role of GDNF. Other signals, including FGF10, can perform many of the functions of GDNF, when SPRY1 is absent. But GDNF/RET signaling has an apparently unique function in determining normal branching pattern. In contrast to GDNF or FGF10, Etv4 and Etv5 represent a critical node in the RTK signaling network that cannot by bypassed by reducing the negative regulation of upstream signals. Kidney development requires the secreted protein GDNF, which signals via its cellular receptor RET to promote growth and branching of the ureteric bud, the progenitor of the collecting duct system. The transcription factors ETV4 and ETV5 regulate gene expression in response to GDNF. We report that deleting Spry1, a feedback inhibitor downstream of RET, largely rescues kidney development in mice lacking GDNF or RET, although not in those lacking ETV4 and ETV5. Thus, GDNF and RET become dispensable in the absence of SPRY1, when their roles can be largely assumed by other signals and receptors, while ETV4 and ETV5 remain indispensible. We identify FGF10 as the signal responsible for kidney development in the combined absence of GDNF/RET signaling and SPRY1 negative regulation. But while the ureteric bud branches extensively in Gdnf−/−;Spry1−/− and Ret−/−;Spry1−/− kidneys, its pattern of branching is severely perturbed. This points to a unique function of GDNF in ureteric bud patterning.
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8
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Sweeney D, Lindström N, Davies JA. Developmental plasticity and regenerative capacity in the renal ureteric bud/collecting duct system. Development 2008; 135:2505-10. [DOI: 10.1242/dev.022145] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Branching morphogenesis of epithelia is an important mechanism in animal development, being responsible for the characteristic architectures of glandular organs such as kidney, lung, prostate and salivary gland. In these systems, new branches usually arise at the tips of existing branches. Recent studies, particularly in kidney, have shown that tip cells express a set of genes distinct from those in the stalks. Tip cells also undergo most cell proliferation, daughter cells either remaining in the tip or being left behind as the tips advance, to differentiate and contribute to new stalk. Published time-lapse observations have suggested, though, that new branches may be able to arise from stalks. This happens so rarely, however, that it is not clear whether this reflects true plasticity and reversal of differentiation, or whether it is just an occasional instance of groups of tip cells being `left behind' by error in a mainly stalk zone. To determine whether cells that have differentiated into stalks really do retain the ability to make new tips, we have removed existing tips from stalks, verified that the stalks are free of tip cells, and assessed the ability of tip-free stalks to initiate new branches. We find stalks to be fully capable of regenerating tips that express typical tip markers, with these tips going on to form epithelial trees, at high frequency. The transition from tip to stalk is therefore reversible, at least for early stages of development. This observation has major implications for models of pattern formation in branching trees, and may also be important for tissue engineering and regenerative medicine.
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Affiliation(s)
- Derina Sweeney
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Nils Lindström
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jamie A. Davies
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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9
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Michael L, Sweeney DE, Davies JA. The lectin Dolichos biflorus agglutinin is a sensitive indicator of branching morphogenetic activity in the developing mouse metanephric collecting duct system. J Anat 2007; 210:89-97. [PMID: 17229286 PMCID: PMC2100263 DOI: 10.1111/j.1469-7580.2006.00670.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The urine collecting duct system of the metanephric kidney develops by growth and branching morphogenesis of an unbranched progenitor tubule, the ureteric bud. Bud branching is mainly dichotomous and new branches form from existing branch tips, which are also the main sites of cell proliferation in the system. This behaviour, and the fact that some genes (e.g. Wnt11, Sox9) are expressed only in tips, suggests that tip cells are in a specific state of differentiation. In this report, we show that the lectin Dolichos biflorus agglutinin (DBA), hitherto regarded and used as a general marker of developing renal collecting ducts, binds to most of the duct system but does not bind to the very tips of growing branches. The zone avoided by DBA corresponds to the zone that expresses Wnt11, and the zone that shows enhanced cell proliferation. If branching of the ureteric bud of cultured embryonic kidneys is inhibited in organ culture, by blocking the kidney's endogenous glial cell-derived neurothrophic factor (GDNF)-based branch-promoting signals, the DBA-binding zone extends to the very end of the tip but is lost from there when branching is re-activated. Similarly, if excess GDNF is provided to growing kidneys, the DBA-free zone expands. DBA-staining status therefore appears to be a sensitive indicator of the morphogenetic activity of the collecting duct system.
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Affiliation(s)
- Lydia Michael
- Centre for Integrative Physiology, Edinburgh University College of Medicine, Edinburgh, UK
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10
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Basson MA, Watson-Johnson J, Shakya R, Akbulut S, Hyink D, Costantini FD, Wilson PD, Mason IJ, Licht JD. Branching morphogenesis of the ureteric epithelium during kidney development is coordinated by the opposing functions of GDNF and Sprouty1. Dev Biol 2006; 299:466-77. [PMID: 17022962 DOI: 10.1016/j.ydbio.2006.08.051] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 05/23/2006] [Accepted: 08/15/2006] [Indexed: 11/26/2022]
Abstract
Branching of ureteric bud-derived epithelial tubes is a key morphogenetic process that shapes development of the kidney. Glial cell line-derived neurotrophic factor (GDNF) initiates ureteric bud formation and promotes subsequent branching morphogenesis. Exactly how GDNF coordinates branching morphogenesis is unclear. Here we show that the absence of the receptor tyrosine kinase antagonist Sprouty1 (Spry1) results in irregular branching morphogenesis characterized by both increased number and size of ureteric bud tips. Deletion of Spry1 specifically in the epithelium is associated with increased epithelial Wnt11 expression as well as increased mesenchymal Gdnf expression. We propose that Spry1 regulates a Gdnf/Ret/Wnt11-positive feedback loop that coordinates mesenchymal-epithelial dialogue during branching morphogenesis. Genetic experiments indicate that the positive (GDNF) and inhibitory (Sprouty1) signals have to be finely balanced throughout renal development to prevent hypoplasia or cystic hyperplasia. Epithelial cysts develop in Spry1-deficient kidneys that share several molecular characteristics with those observed in human disease, suggesting that Spry1 null mice may be useful animal models for cystic hyperplasia.
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Affiliation(s)
- M Albert Basson
- Division of Hematology/Oncology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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11
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Caruana G, Cullen-McEwen L, Nelson AL, Kostoulias X, Woods K, Gardiner B, Davis MJ, Taylor DF, Teasdale RD, Grimmond SM, Little MH, Bertram JF. Spatial gene expression in the T-stage mouse metanephros. Gene Expr Patterns 2006; 6:807-25. [PMID: 16545622 DOI: 10.1016/j.modgep.2006.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 01/31/2006] [Accepted: 02/03/2006] [Indexed: 01/28/2023]
Abstract
The E11.5 mouse metanephros is comprised of a T-stage ureteric epithelial tubule sub-divided into tip and trunk cells surrounded by metanephric mesenchyme (MM). Tip cells are induced to undergo branching morphogenesis by the MM. In contrast, signals within the mesenchyme surrounding the trunk prevent ectopic branching of this region. In order to identify novel genes involved in the molecular regulation of branching morphogenesis we compared the gene expression profiles of isolated tip, trunk and MM cells using Compugen mouse long oligo microarrays. We identified genes enriched in the tip epithelium, sim-1, Arg2, Tacstd1, Crlf-1 and BMP7; genes enriched in the trunk epithelium, Innp1, Itm2b, Mkrn1, SPARC, Emu2 and Gsta3 and genes spatially restricted to the mesenchyme surrounding the trunk, CSPG2 and CV-2, with overlapping and complimentary expression to BMP4, respectively. This study has identified genes spatially expressed in regions of the developing kidney involved in branching morphogenesis, nephrogenesis and the development of the collecting duct system, calyces, renal pelvis and ureter.
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Affiliation(s)
- Georgina Caruana
- Department of Anatomy and Cell Biology, Monash University, Clayton, Vic., Australia.
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12
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Abstract
Signaling by GDNF through the Ret receptor is required for normal growth of the ureteric bud during kidney development. However, the precise role of GDNF/Ret signaling in renal branching morphogenesis and the specific responses of ureteric bud cells to GDNF remain unclear. Recent studies have provided new insight into these issues. The localized expression of GDNF by the metanephric mesenchyme, together with several types of negative regulation, is important to elicit and correctly position the initial budding event from the Wolffian duct. GDNF also promotes the continued branching of the ureteric bud. However, it does not provide the positional information required to specify the pattern of ureteric bud growth and branching, as its site of synthesis can be drastically altered with minimal effects on kidney development. Cells that lack Ret are unable to contribute to the tip of the ureteric bud, apparently because GDNF-driven proliferation is required for the formation and growth of this specialized epithelial domain.
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Affiliation(s)
- Frank Costantini
- Department of Genetics and Development, Columbia University Medical Center, New York 10032, USA.
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13
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Abstract
BACKGROUND Branching morphogenesis of the ureteric bud/collecting duct epithelium is an important feature of kidney development. Recent work has identified many transcription factors and paracrine signaling molecules that regulate branching, but the physical mechanisms by which these signals act remain largely unknown. The actin cytoskeleton is a common component of mechanisms of morphogenesis. We have therefore studied the expression of, and requirement for actin filaments in the ureteric bud, a branching epithelium of the mammalian kidney. METHODS Embryonic kidney rudiments were grown in organ culture. Actin expression in kidneys growing normally and those in which branching was inhibited was examined using labeled phalloidin. The morphogenetic effects of inhibiting actin organization and tension using cytochalasin D, butanedione monoxime, and Rho kinase ROCK inhibitors were assessed using immunofluorescence. RESULTS F-actin is expressed particularly strongly in the apical domains of cells at the tips of branching ureteric bud, but this expression depends on the bud actively growing and branching. Blocking the polymerization of actin using cytochalasin D inhibits ureteric bud branching reversibly, as does blocking myosin function using butadiene monoxime. Inhibiting the activation of ROCK, a known activator of myosin, with the drugs Y27632 or with H1152 inhibits the expression of strong actin bundles in the ureteric bud tips and inhibits ureteric bud branching without inhibiting other aspects of renal development. CONCLUSION The formation of tension-bearing actin-myosin complexes is essential for branching morphogenesis in the developing kidney.
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Affiliation(s)
- Lydia Michael
- Centre for Integrative Physiology, Edinburgh University College of Medicine, Scotland, UK
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14
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Shakya R, Jho EH, Kotka P, Wu Z, Kholodilov N, Burke R, D'Agati V, Costantini F. The role of GDNF in patterning the excretory system. Dev Biol 2005; 283:70-84. [PMID: 15890330 DOI: 10.1016/j.ydbio.2005.04.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 03/28/2005] [Accepted: 04/06/2005] [Indexed: 11/19/2022]
Abstract
Mesenchymal-epithelial interactions are an important source of information for pattern formation during organogenesis. In the developing excretory system, one of the secreted mesenchymal factors thought to play a critical role in patterning the growth and branching of the epithelial ureteric bud is GDNF. We have tested the requirement for GDNF as a paracrine chemoattractive factor by altering its site of expression during excretory system development. Normally, GDNF is secreted by the metanephric mesenchyme and acts via receptors on the Wolffian duct and ureteric bud epithelium. Misexpression of GDNF in the Wolffian duct and ureteric buds resulted in formation of multiple, ectopic buds, which branched independently of the metanephric mesenchyme. This confirmed the ability of GDNF to induce ureter outgrowth and epithelial branching in vivo. However, in mutant mice lacking endogenous GDNF, kidney development was rescued to a substantial degree by GDNF supplied only by the Wolffian duct and ureteric bud. These results indicate that mesenchymal GDNF is not required as a chemoattractive factor to pattern the growth of the ureteric bud within the developing kidney, and that any positional information provided by the mesenchymal expression of GDNF may provide for renal branching morphogenesis is redundant with other signals.
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Affiliation(s)
- Reena Shakya
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
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15
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Shakya R, Watanabe T, Costantini F. The role of GDNF/Ret signaling in ureteric bud cell fate and branching morphogenesis. Dev Cell 2005; 8:65-74. [PMID: 15621530 DOI: 10.1016/j.devcel.2004.11.008] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Revised: 09/17/2004] [Accepted: 10/05/2004] [Indexed: 11/29/2022]
Abstract
While GDNF signaling through the Ret receptor is critical for kidney development, its specific role in branching morphogenesis of the epithelial ureteric bud (UB) is unclear. Ret expression defines a population of UB "tip cells" distinct from cells of the tubular "trunks," but how these cells contribute to UB growth is unknown. We have used time-lapse mosaic analysis to investigate normal cell fates within the growing UB and the developmental potential of cells lacking Ret. We found that normal tip cells are bipotential, contributing to both tips and trunks. Cells lacking Ret are specifically excluded from the tips, although they contribute to the trunks, revealing that the tips form and expand by GDNF-driven cell proliferation. Surprisingly, the mutant cells assumed an asymmetric distribution in the UB trunks, suggesting a model of branching in which the epithelium of the tip and the adjacent trunk is remodeled to form new branches.
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Affiliation(s)
- Reena Shakya
- Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, 701 West 168th Street, New York, NY 10032, USA
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16
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Abstract
Branched epithelia determine the anatomy of many mammalian organs; understanding how they develop is therefore an important element of understanding organogenesis as a whole. In recent years, much progress has been made in identifying paracrine factors that regulate branching morphogenesis in many organs, but comparatively little attention has been paid to the mechanisms of morphogenesis that translate these signals into anatomical change. Localized cell proliferation is a potentially powerful mechanism for directing the growth of a developing system to produce a specific final morphology. We have examined the pattern of cell proliferation in the ureteric bud system of the embryonic murine metanephric kidneys developing in culture. We detect a zone of high proliferation at the site of the presumptive ureteric bud even before it emerges from the Wolffian duct and later, as ureteric bud morphogenesis continues, proliferation is localized mainly in the very tips of the branching epithelium. Blocking cell cycling using methotrexate inhibits ureteric bud emergence. The proliferative zone is present at ureteric bud tips only when they are undergoing active morphogenesis; if branching is inhibited either by treatment with natural negative regulators (TGF-beta) or with antagonists of natural positive regulators (GDNF, glycosaminoglycans) then proliferation at the tips falls back to levels characteristic of the stalks behind them. Our results suggest that localized proliferation is an important morphogenetic mechanism in kidney development.
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Affiliation(s)
- Lydia Michael
- Genes and Development Group, University of Edinburgh College of Medicine, UK.
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17
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Wanigasekara Y, Airaksinen MS, Heuckeroth RO, Milbrandt J, Keast JR. Neurturin signalling via GFRα2 is essential for innervation of glandular but not muscle targets of sacral parasympathetic ganglion neurons. Mol Cell Neurosci 2004; 25:288-300. [PMID: 15019945 DOI: 10.1016/j.mcn.2003.10.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2003] [Revised: 10/20/2003] [Accepted: 10/23/2003] [Indexed: 10/26/2022] Open
Abstract
Neurturin, a member of the glial cell-derived neurotrophic factor familys of ligands, is important for development of many cranial parasympathetic ganglion neurons. We have investigated the sacral component of the parasympathetic nervous system in mice with gene deletions for neurturin or its preferred receptor, GFRalpha2. Disruption of neurturin signalling decreased cholinergic VIP innervation to the mucosa of the reproductive organs, but not to the smooth muscle layers of these organs or to the urinary bladder. Thus, neurturin and its receptor are involved in parasympathetic innervation of a select group of pelvic visceral tissues. In contrast, noradrenergic innervation was not affected by the gene ablations. The epithelium of reproductive organs from knockout animals was atrophied, indicating that cholinergic innervation may be important for the maintenance of normal structure. Cholinergic neurons express GFRalpha2 on their terminals and somata, indicating they can respond to neurotrophic support, and their somata are smaller when neurturin signalling is disrupted. Colocalisation studies showed that many peripheral glia express GFRalpha2 although its role in these cells is yet to be determined. Our results indicate that neurturin, acting through GFRalpha2, is essential for parasympathetic innervation of the mucosae of reproductive organs, as well as for maintenance of a broader group of sacral parasympathetic neurons.
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Affiliation(s)
- Y Wanigasekara
- Prince of Wales Medical Research Institute and University of New South Wales, Randwick 2031, Australia
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Camassei FD, Boldrini R, Jenkner A, Inserra A, Donfrancesco A, Rava L, Dominici C. Expression of glial cell line-derived neurotrophic factor and neurturin in mature kidney, nephrogenic rests, and nephroblastoma: possible role as differentiating factors. Pediatr Dev Pathol 2003; 6:511-9. [PMID: 15018450 DOI: 10.1007/s10024-003-2013-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Kidney development involves a series of complex interactions between the ureteric bud and undifferentiated mesenchyme, resulting in the production of the nephron unit. Among locally derived soluble factors, a particular relevance has been recognized to glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) for the mesenchyme-to-epithelial conversion of a metanephron. Nephroblastoma is a developmental tumor of the kidney deriving from metanephric blastema that mimics renal development and may offer an adequate model of human nephrogenesis. We investigated the immunohistochemical expression of GDNF, NTN, and their receptors (GFRalpha1, 2, and 3, and Ret) in normal human kidney and in 42 nephroblastomas, 20 of which were associated with nephrogenic rests (group A) and 22 were not (group B). We compared the immunostaining pattern in group A vs. group B and correlated clinical course with stage, grade, presence of nephrogenic rests, and immunohistochemical findings. GDNF, NTN, and their receptors were expressed in mature kidney and in 67% (GDNF) and 33% (NTN) of tumors, particularly in the epithelial component; precursor lesions were negative. No significant differences of expression were observed between groups A and B tumors. Low stage (P = 0.012), absence of nephrogenic rests (P = 0.016), intense expression of GDNF (P = 0.034), and NTN (P = 0.05) were associated with a more favorable outcome. Besides inductive activity in nephrogenesis, GDNF and NTN may play a role in maintaining differentiation and survival functions in mature kidney and may contribute to induce differentiation of nephroblastoma cells toward the less aggressive epithelial component. The pathway of activation seems to follow an autocrine/paracrine mechanism, as neurotrophic factors, GFRalpha1-2-3 receptors and Ret are coexpressed.
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Kawakami T, Wakabayashi Y, Aimi Y, Isono T, Okada Y. Developmental expression of glial cell-line derived neurotrophic factor, neurturin, and their receptor mRNA in the rat urinary bladder. Neurourol Urodyn 2003; 22:83-8. [PMID: 12478607 DOI: 10.1002/nau.10074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
AIMS Glial cell-line derived neurotrophic factor (GDNF) and related factors neurturin (NRTN), artemin, and persephin are members of the GDNF family of neurotrophic factors. GDNF and NRTN bind to the tyrosine kinase receptor Ret and the receptors GFRalpha1 and GFRalpha2. The objective was to examine the developmental expression of GDNF, NRTN, and their receptors within the rat urinary bladder. METHODS Rat bladders dissected from embryonic day (E) 15, postnatal day (P) 0, P14, P28, and adult rats (P60) were investigated by semiquantitative reverse transcriptase polymerase chain reaction. Embryos (E15, E16, and E17) were immunohistochemically stained for neurofilament. RESULTS GDNF and Ret mRNA levels at E15 were the highest of all the stages we examined and then immediately decreased. In contrast, NRTN mRNA levels did not change between E15 and postnatal day 14; thereafter, they gradually but insignificantly increased. GFRalpha1 and GFRalpha2 mRNA levels were high at E15, after which their signal intensities decreased. In whole-mounted specimens, neurofilament-positive axons were first detected in the bladder at E16. CONCLUSIONS Our results suggest that GDNF and NRTN may act as trophic factors for neural in-growth to the bladder and/or for the maintenance of mature neurons innervating the bladder. These factors might also be involved in bladder morphogenesis.
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Affiliation(s)
- Takahiro Kawakami
- Department of Urology, Shiga University of Medical Science, Otsu, Japan
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20
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Abstract
Formation of branching epithelial trees from unbranched precursors is a common process in animal organogenesis. In humans, for example, this process gives rise to the airways of the lungs, the urine-collecting ducts of the kidneys and the excretory epithelia of the mammary, prostate and salivary glands. Branching in these different organs, and in different animal classes and phyla, is morphologically similar enough to suggest that they might use a conserved developmental programme, while being dissimilar enough not to make it obviously certain that they do. In this article, I review recent discoveries about the molecular regulation of branching morphogenesis in the best-studied systems, and present evidence for and against the idea of there being a highly conserved mechanism. Overall, I come to the tentative conclusion that key mechanisms are highly conserved, at least within vertebrates, but acknowledge that more work needs to be done before the case is proved beyond reasonable doubt.
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Affiliation(s)
- Jamie A Davies
- Anatomy Building, Edinburgh University Medical School, Scotland.
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21
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Abstract
Branching morphogenesis of epithelium is a common and important feature of organogenesis; it is, for example, responsible for development of renal collecting ducts, lung airways, milk ducts of mammary glands and seminal ducts of the prostate. In each case, epithelial development is controlled by a variety of mesenchyme-derived molecules, both soluble (e.g. growth factors) and insoluble (e.g. extracellular matrix). Little is known about how these varied influences are integrated to produce a coherent morphogenetic response, but integration is likely to be achieved at least partly by cytoplasmic signal transduction networks. Work in other systems (Drosophila tracheae, MDCK models) suggests that the mitogen-activated protein (MAP) kinase pathway might be important to epithelial branching. We have investigated the role of the MAP kinase pathway in one of the best characterised mammalian examples of branching morphogenesis, the ureteric bud of the metanephric kidney. We find that Erk MAP kinase is normally active in ureteric bud, and that inhibiting Erk activation with the MAP kinase kinase inhibitor, PD98059, reversibly inhibits branching in a dose-dependent manner, while allowing tubule elongation to continue. When Erk activation is inhibited, ureteric bud tips show less cell proliferation than controls and they also produce fewer laminin-rich processes penetrating the mesenchyme and fail to show the strong concentration of apical actin filaments typical of controls; apoptosis and expression of Ret and Ros, are, however, normal. The activity of the Erk MAP kinase pathway is dependent on at least two known regulators of ureteric bud branching; the GDNF-Ret signalling system and sulphated glycosaminoglycans. MAP kinase is therefore essential for normal branching morphogenesis of the ureteric bud, and lies downstream of significant extracellular regulators of ureteric bud development.
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Affiliation(s)
- C E Fisher
- Centre for Developmental Biology, Department of Biomedical Sciences, University of Edinburgh, George Square, Edinburgh, UK
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22
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Abstract
Germline mutations in the RET proto-oncogene are responsible for two unrelated neural crest disorders: Hirschsprung disease, a congenital absence of the enteric nervous system in the hindgut, and multiple endocrine neoplasia type 2, a dominantly inherited cancer syndrome. Moreover, somatic rearrangements of RET are causally involved in the genesis of papillary thyroid carcinoma. The receptor tyrosine kinase encoded by the RET gene acts as the subunit of a multimolecular complex that binds four distinct ligands and activates a signalling network crucial for neural and kidney development. Over the past few years, a clearer picture of the mode of RET activation and of its multifaceted role during development has started to emerge. These findings, which provide new clues to the molecular mechanisms underlying RET signalling dysfunction in Hirschsprung disease, are summarized in this review.
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Affiliation(s)
- S Manié
- Laboratoire de Génétique, CNRS UMR 5641, Domaine Rockefeller, 8 avenue Rockefeller, 69373 Cedex 08, Lyon, France
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23
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Abstract
BACKGROUND The exact molecular mechanisms that regulate ureteric branching morphogenesis in the developing metanephros have not been fully elucidated. However, in vivo and in vitro evidence indicates that glial cell line-derived neurotrophic factor (GDNF) is a key regulator of the initiation of ureteric branching. GDNF knockout mice show renal agenesis or severe dysgenesis and die 24 hours after birth from renal failure. Inhibition of GDNF activity in metanephric organ culture inhibits ureteric branching. Since nephron initiation only occurs at the tips of ureteric branches, the aim of the present study was to determine whether nephron number in GDNF heterozygous mice is reduced. METHODS Male GDNF heterozygous mice of hybrid 129/Sv and C57/BL genetic background were mated with C57BL/6 females. Offspring were genotyped at postnatal day 30 (PN30) by polymerase chain reaction. Left kidneys were used for estimating kidney volume and total nephron number. We also estimated absolute and relative volumes of ureteric duct epithelium. Unbiased stereological methods were used throughout (Cavalieri method, physical disector/fractionator combination). RESULTS GDNF wild-type and heterozygous mice had similar body weights at PN30. However, heterozygous kidneys were 25% smaller than wild-type kidneys (wild-type, 114.75 +/- 16.46 mm3; heterozygous, 87.11 +/- 21.84 mm3, P < 0.001) and contained approximately 30% fewer nephrons (wild-type, 11886 +/- 1277; heterozygous, 8573 +/- 2240, P < 0.01). In addition, the absolute ureteric duct volume was significantly reduced in heterozygous mice (P < 0.001). CONCLUSIONS : These results indicate that the loss of one GDNF allele results in reduced nephron endowment in the adult kidney, presumably as the result of reduced branching morphogenesis of the ureteric bud.
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Affiliation(s)
- L A Cullen-McEwen
- Department of Anatomy and Cell Biology, Department of Medicine, Monash University, Clayton, Victoria, Australia
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24
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Abstract
The urinary collecting duct system of the permanent kidney develops by growth and branching of an initially unbranched epithelial tubule, the ureteric bud. Formation of the ureteric bud as an outgrowth of the wolffian duct is induced by signalling molecules (such as GDNF) that emanate from the adjacent metanephrogenic mesenchyme. Once it has invaded the mesenchyme, growth and branching of the bud is controlled by a variety of molecules, such as the growth factors GDNF, HGF, TGFbeta, activin, BMP-2, BMP-7, and matrix molecules such as heparan sulphate proteoglycans and laminins. These various influences are integrated by signal transduction systems inside ureteric bud cells, with the MAP kinase, protein kinase A and protein kinase C pathways appearing to play major roles. The mechanisms of morphogenetic change that produce branching remain largely obscure, but matrix metalloproteinases are known to be necessary for the process, and there is preliminary evidence for the involvement of the actin/myosin contractile cytoskeleton in creating branch points.
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Affiliation(s)
- J Davies
- Department of Anatomy, Edinburgh University Medical School, UK.
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25
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Abstract
Epithelial tissues such as kidney, lung, and breast arise through branching morphogenesis of a pre-existing epithelial structure. They share common morphological stages and a need for regulation of a similar set of developmental decisions--where to start; when, where, and in which direction to branch; and how many times to branch--decisions requiring regulation of cell proliferation, apoptosis, invasiveness, and cell motility. It is likely that similar molecular mechanisms exist for the epithelial branching program. Here we focus on the development of the collecting system of the kidney, where, from recent data using embryonic organ culture, cell culture models of branching morphogenesis, and targeted gene deletion experiments, the outlines of a working model for branching morphogenesis begin to emerge. Key branching morphogenetic molecules in this model include growth factors, transcription factors, distal effector molecules (such as extracellular matrix proteins, integrins, proteinases and their inhibitors), and genes regulating apoptosis and cell proliferation.
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Affiliation(s)
- M Pohl
- Department of Pediatrics, University of California, San Diego, La Jolla 92093-0693, USA
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26
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Abstract
For more than 40 years now, the developing kidney has served as a model paradigm for epithelial-mesenchymal interactions. The principles of inductive signaling, epithelial cell differentiation, and pattern formation are now being addressed with modern genetic and biochemical tools. In addition to the mammalian kidney organ culture model, both zebrafish and Xenopus laevis demonstrate great potential for investigating the molecular mechanisms of kidney organogenesis within a whole organism. In this review, the papers presented in this special issue are discussed with respect to recent progress in the renal development field. Coincidentally, it has become increasingly clear that progress made in renal development can impact our understanding of the genetic basis of disease.
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Affiliation(s)
- G R Dressler
- Department of Pathology, University of Michigan, Ann Arbor 48109, USA.
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