1
|
Kim SH, Hu Y, Cadman S, Bouloux P. Diversity in fibroblast growth factor receptor 1 regulation: learning from the investigation of Kallmann syndrome. J Neuroendocrinol 2008; 20:141-63. [PMID: 18034870 DOI: 10.1111/j.1365-2826.2007.01627.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unravelling of the genetic basis of the hypogonadotrophic hypogonadal disorders, including Kallmann syndrome (KS), has led to renewed interest into the developmental biology of gonadotrophin-releasing hormone (GnRH) neurones and, more generally, into the molecular mechanisms of reproduction. KS is characterised by the association of GnRH deficiency with diminished olfaction. Until recently, only two KS-associated genes were known: KAL1 and KAL2. KAL1 encodes the cell membrane and extracellular matrix-associated secreted protein anosmin-1 which is implicated in the X-linked form of KS. Anosmin-1 shows high affinity binding to heparan sulphate (HS) and its function remains the focus of ongoing investigation, although a role in axonal guidance and neuronal migration, which are processes essential for normal GnRH ontogeny and olfactory bulb histogenesis, has been suggested. KAL2, identified as the fibroblast growth factor receptor 1 (FGFR1) gene, has now been recognised to be the underlying genetic defect for an autosomal dominant form of KS. The diverse signalling pathways initiated upon FGFR activation can elicit pleiotropic cellular responses depending on the cellular context. Signalling through FGFR requires HS for receptor dimerisation and ligand binding. Current evidence supports a HS-dependent interaction between anosmin-1 and FGFR1, where anosmin-1 serves as a co-ligand activator enhancing the signal activity, the finer details of whose mechanism remain the subject of intense investigation. Recently, mutations in the genes encoding prokineticin 2 (PK2) and prokineticin receptor 2 (PKR2) were reported in a cohort of KS patients, further reinforcing the view of KS as a multigenic trait involving divergent pathways. Here, we review the historical and current understandings of KS and discuss the latest findings from the molecular and cellular studies of the KS-associated proteins, and describe the evidence that suggests convergence of several of these pathways during normal GnRH and olfactory neuronal ontogeny.
Collapse
Affiliation(s)
- S-H Kim
- Centre for Neuroendocrinology, Royal Free and University College Medical School, University College London, London, UK.
| | | | | | | |
Collapse
|
2
|
Hu Y, González-Martínez D, Kim SH, Bouloux PMG. Cross-talk of anosmin-1, the protein implicated in X-linked Kallmann's syndrome, with heparan sulphate and urokinase-type plasminogen activator. Biochem J 2005; 384:495-505. [PMID: 15324302 PMCID: PMC1134135 DOI: 10.1042/bj20041078] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Defective function of anosmin-1, the protein encoded by KAL-1, underlies X-linked Kallmann's syndrome (X-KS), a human hereditary developmental disorder. Anosmin-1 appears to play a role in neurite outgrowth and axon branching, although molecular mechanisms of its action are still unknown. Anosmin-1 contains a WAP (whey acidic protein-like) domain and four contiguous FnIII (fibronectin-like type III) repeats; its WAP domain shows similarity to known serine protease inhibitors, whereas the FnIII domains contain HS (heparan sulphate)-binding sequences. To investigate the functional role of these domains, we have generated both wild-type and mutant recombinant anosmin-1 proteins using a Drosophila S2 cell expression system. Here we present the first biochemical evidence demonstrating the high-binding affinity between HS and anosmin-1, as measured by SPR (surface plasmon resonance) (K(d)=2 nM). The FnIII domains, particularly the first, are essential for dose-dependent HS binding and HS-mediated cell surface association. Furthermore, we have identified uPA (urokinase-type plasminogen activator) as an anosmin-1 interactant. Anosmin-1 significantly enhances the amidolytic activity of uPA in vitro; and anosmin-1-HS-uPA co-operation induces cell proliferation in the PC-3 prostate carcinoma cell line. Both the HS interaction and an intact WAP domain are required for the mitogenic activity of anosmin-1. These effects appear to be mediated by a direct protein interaction between anosmin-1 and uPA, since anosmin-1-uPA could be co-immunoprecipitated from PC-3 cell lysates, and their direct binding with high affinity (K(d)=6.91 nM) was demonstrated by SPR. We thus propose that anosmin-1 may modulate the catalytic activity of uPA and its signalling pathway, whereas HS determines cell surface localization of the anosmin-1-uPA complex.
Collapse
Affiliation(s)
- Youli Hu
- Centre for Neuroendocrinology, Royal Free and University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK.
| | | | | | | |
Collapse
|
3
|
Wagner SN, Atkinson MJ, Wagner C, Höfler H, Schmitt M, Wilhelm O. Sites of urokinase-type plasminogen activator expression and distribution of its receptor in the normal human kidney. Histochem Cell Biol 1996; 105:53-60. [PMID: 8824906 DOI: 10.1007/bf01450878] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The urokinase-type plasminogen activator (uPA) is secreted into the urine at high concentrations and both the uPA protein and mRNA are present in human renal tissue. Normal kidney tissue also expresses the receptor for uPA. Neither the precise sites of uPA mRNA expression, nor the distribution of the uPA-receptor antigen, have been elucidated in the human kidney. In the present study, the sites of uPA mRNA expression were identified by in situ hybridization, and the cellular localization of both uPA and uPA-receptor was determined by immunohistochemical analysis. High-level uPA mRNA expression was restricted to epithelial cells of the convoluted proximal tubules and the thick ascending limb of Henle's loop (the straight part of the distal tubule). However, uPA immunoreactivity was not confined to sites of uPA mRNA expression, but was present in all segments of the tubular epithelium. Tubular epithelial cells also exhibited a consistent immunoreactivity with uPA-receptor antibody, indicative of a co-localization of the uPA antigen and its receptor in the uriniferous epithelium. We propose that the uPA antigen expression in nephron segments lacking demonstrable endogenous uPA synthesis may be the result of a uPA-receptor-mediated uptake of uPA.
Collapse
Affiliation(s)
- S N Wagner
- Institut für Pathologie, GSF-Forschungszentrum für Umwelt und Gesundheit, Oberschleissheim, Germany
| | | | | | | | | | | |
Collapse
|
4
|
Brown PA, Wilson HM, Reid FJ, Booth NA, Simpson JG, Morrison L, Power DA, Haites NE. Urokinase-plasminogen activator is synthesized in vitro by human glomerular epithelial cells but not by mesangial cells. Kidney Int 1994; 45:43-7. [PMID: 8127020 DOI: 10.1038/ki.1994.5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The plasmin protease system may have a role in maintaining the patency of renal tubules and in regulating matrix degradation within the glomerulus. Urokinase-plasminogen activator (u-PA) is a serine protease which plays an important part in the regulation of plasmin production from plasminogen. The synthesis of u-PA by cultured human glomerular cells, in particular mesangial cells, is controversial. The present study describes the presence of u-PA in supernatants of pure cultures of human glomerular epithelial cells (EC), cocultures of EC and human mesangial cells (MC) and whole glomeruli, but not within pure cultures of MC. To confirm the synthesis of u-PA mRNA in glomerular EC, cocultures of EC and MC were tested by in situ hybridization with u-PA antisense and sense digoxigenin-labeled RNA probes. Cytoplasmic localization of u-PA mRNA was demonstrated only in the EC, thus confirming the absence of synthesis of u-PA by human mesangial cells in culture.
Collapse
Affiliation(s)
- P A Brown
- Department of Pathology, University of Aberdeen, Scotland, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
5
|
Sumi Y, Dent MA, Owen DE, Seeley PJ, Morris RJ. The expression of tissue and urokinase-type plasminogen activators in neural development suggests different modes of proteolytic involvement in neuronal growth. Development 1992; 116:625-37. [PMID: 1289056 DOI: 10.1242/dev.116.3.625] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tissue and urokinase-type plasminogen activators are serine proteases with highly restricted specificity, their best characterised role being to release the broad specificity protease plasmin from inactive plasminogen. It has frequently been suggested that these, and similar proteases, are involved in axonal growth and tissue remodelling associated with neural development. To help define what this role might be, we have studied the expression of the plasminogen activators in developing rat nervous tissue. Urokinase-type plasminogen activator mRNA is strongly expressed by many classes of neurons in peripheral and central nervous system. We have analysed its appearance in spinal cord and sensory ganglia, and found the mRNA is detectable by in situ hybridisation very early in neuronal development (by embryonic day 12.5), at a stage compatible with it playing a role in axonal or dendritic growth. Tissue plasminogen activator mRNA, on the other hand, is expressed only by cells of the floor plate in the developing nervous system, from embryonic day 10.5 and thereafter. Immunohistochemical and enzymatic analysis showed that active tissue plasminogen activator is produced by, and retained within, the floor plate. A mechanism is suggested by which high levels of tissue plasminogen activator produced by the stationary cells of the floor plate could influence the direction of growth of commissural axons as they pass through this midline structure.
Collapse
Affiliation(s)
- Y Sumi
- Norman and Sadie Lee Centre, Laboratory of Neurobiology, National Institute for Medical Research, London, UK
| | | | | | | | | |
Collapse
|
6
|
Zacharias U, Will H. Characterization of a tissue-type plasminogen activator from porcine urine. FEBS Lett 1991; 289:155-8. [PMID: 1915841 DOI: 10.1016/0014-5793(91)81058-g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Porcine urine, unlike human urine, does not contain detectable amounts of urokinase-type plasminogen activator (u-PA). The plasminogen activator present in porcine urine is of tissue-type (t-PA) as identified by the following criteria. (1) Porcine urine PA exhibits an Mr of 65,000 similar to the Mr of human t-PA (64-70,000) but distinct from the Mr of human u-PA (55,000). (2) Antibodies against human t-PA bind and inhibit crude and purified porcine urine PA, while human u-PA-specific antibodies do not react with porcine urine PA. (3) Plasminogen activation by porcine urine PA is markedly stimulated in the presence of fibrinogen fragments. (4) Porcine urine PA activity is not affected by concentration of amiloride substantially suppressing human u-PA activity.
Collapse
Affiliation(s)
- U Zacharias
- Department of Enzymology, Central Institute of Molecular Biology, Berlin, Germany
| | | |
Collapse
|
7
|
Littlefield BA. Plasminogen activators in endometrial physiology and embryo implantation: a review. Ann N Y Acad Sci 1991; 622:167-75. [PMID: 1829593 DOI: 10.1111/j.1749-6632.1991.tb37860.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- B A Littlefield
- Section of Biology, Eisai Research Institute, Andover, Massachusetts 01810
| |
Collapse
|
8
|
Sappino AP, Huarte J, Vassalli JD, Belin D. Sites of synthesis of urokinase and tissue-type plasminogen activators in the murine kidney. J Clin Invest 1991; 87:962-70. [PMID: 1900311 PMCID: PMC329888 DOI: 10.1172/jci115104] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Kidneys have long been recognized as a major source of plasminogen activators (PAs). However, neither the sites of synthesis of the enzymes nor their role in renal function have been elucidated. By the combined use of zymographies on tissue sections and in situ hybridizations, we have explored the cellular distribution of urokinase-type (u-PA) and tissue-type (t-PA) plasminogen activators and of their mRNAs in developing and adult mouse kidneys. In 17.5-d old embryos, renal tubules synthesize u-PA, while S-shaped bodies produce t-PA. In the adult kidney, u-PA is synthesized and released in urine by the epithelial cells lining the straight parts of both proximal and distal tubules. In contrast, t-PA is produced by glomerular cells and by epithelial cells lining the distal part of collecting ducts. The precise segmental distribution of PAs suggests that both enzymes may be implicated in the maintenance of tubular patency, by catalyzing extracellular proteolysis to prevent or circumvent protein precipitation.
Collapse
Affiliation(s)
- A P Sappino
- Division of Onco-Haematology, University of Geneva Medical School, Switzerland
| | | | | | | |
Collapse
|
9
|
Gross TJ, Simon RH, Sitrin RG. Expression of urokinase-type plasminogen activator by rat pulmonary alveolar epithelial cells. Am J Respir Cell Mol Biol 1990; 3:449-56. [PMID: 2121171 DOI: 10.1165/ajrcmb/3.5.449] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Intra-alveolar fibrin deposition accompanies many forms of inflammatory lung injury. Appropriate clearance of this fibrin matrix is important for normal healing and remodeling. The local generation of plasmin by the action of plasminogen activators (PAs) represents a pivotal step in the fibrinolytic process. To investigate whether the alveolar epithelium plays a role in the modulation of intra-alveolar fibrinolysis, we have studied PA regulation by rat pulmonary alveolar epithelial cells. We have found large quantities of PA activity both in conditioned media and cell lysates from epithelial monolayers in culture. Casein-plasminogen zymography reveals that this PA activity migrates as a tight doublet with an apparent mol wt of 45 kD, clearly distinct from rat tissue-type PA (tPA, greater than 68 kD). Analysis of freshly isolated type II alveolar epithelial cells demonstrates readily measurable PA activity in cell lysates, as well as expression of urokinase-type PA (uPA) mRNA on Northern blot analysis. Upregulation of PA activity occurs progressively with time in culture as the alveolar epithelial cells lose type II cell characteristics and become more flattened. Stimulation of alveolar epithelial cell monolayers with lipopolysaccharide or tumor necrosis factor increases levels of secreted PA activity. The relative abundance of uPA mRNA was shown to change in parallel with PA activity during in vitro differentiation or after exposure to inflammatory mediators. Thus, alveolar epithelial cells are likely an important source of uPA in the lung, the expression of which is influenced by the state of cellular differentiation as well as the presence of inflammatory mediators.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- T J Gross
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor
| | | | | |
Collapse
|
10
|
Scott JN, Jennes LH. Ontogeny of atrial natriuretic peptide receptors in fetal rat kidney and adrenal gland. HISTOCHEMISTRY 1989; 91:395-400. [PMID: 2542191 DOI: 10.1007/bf00493826] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
With in vitro autoradiography, specific receptors for atrial natriuretic peptide (ANP) were localized in fetal rat kidney and adrenal glands. Receptors were present over renal vesicles, in the primitive renal medulla and throughout the adrenal gland as early as 16 days gestation. By 20 days gestation, several layers of developing renal corpuscles were present and ANP receptors were localized over developing glomeruli in each layer. Larger accumulations occurred over the juxtamedullary glomeruli. In the medulla, the receptors were localized in a reticular pattern near the pelvis. With emulsion coated sections, ANP receptors in developing renal corpuscles were seen primarily over the lower curve of S-shaped vesicles and around the periphery of the more mature corpuscles. In the renal medulla, receptors were localized over the interstitial cells. In the 16-day-old adrenal gland, ANP receptors were present throughout the cortical area but at 20 days gestation and 1 day postpartum receptors appeared more numerous in the peripheral region. These data suggest that ANP has important developmental effects in the kidney and adrenal gland and may be involved in regulation of body fluid homeostasis in the late gestation rat fetus.
Collapse
Affiliation(s)
- J N Scott
- Department of Anatomy, Wright State University, Dayton, OH 45435
| | | |
Collapse
|