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Piras M, Gerosa C, Congiu T, Cau F, Fanni D, Pichiri G, Coni P, Lachowicz JI, Schirru E, Congia M, Rossino R, Muntoni S, Jaremko M, Piludu M. Toward the renal vesicle: Ultrastructural investigation of the cap mesenchyme splitting process in the developing kidney. J Public Health Res 2022; 11:22799036221124076. [PMID: 36310827 PMCID: PMC9597041 DOI: 10.1177/22799036221124076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/02/2022] [Indexed: 11/09/2022] Open
Abstract
Background A complex sequence of morphogenetic events leads to the development of the adult mouse kidney. In the present study, we investigated the morphological events that characterize the early stages of the mesenchymal-to-epithelial transition of cap mesenchymal cells, analyzing in depth the relationship between cap mesenchymal induction and ureteric bud (UB) branching. Design and methods Normal kidneys of newborn non-obese diabetic (NOD) mice were excised and prepared for light and electron microscopic examination. Results Nephrogenesis was evident in the outer portion of the renal cortex of all examined samples. This process was mainly due to the interaction of two primordial derivatives, the ureteric bud and the metanephric mesenchyme. Early renal developmental stages were initially characterized by the formation of a continuous layer of condensed mesenchymal cells around the tips of the ureteric buds. These caps of mesenchymal cells affected the epithelial cells of the underlying ureteric bud, possibly inducing their growth and branching. Conclusions The present study provides morphological evidence of the reciprocal induction between the ureteric bud and the metanephric mesenchyme showing that the ureteric buds convert mesenchyme to epithelium that in turn stimulates the growth and the branching of the ureteric bud.
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Affiliation(s)
- Monica Piras
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Clara Gerosa
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Terenzio Congiu
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy,Terenzio Congiu, Department of Medical
Sciences and Public Health, AOU, University of Cagliari, Via Ospedale Cagliari,
Cagliari, Sardegna 09124, Italy.
| | - Flaviana Cau
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Daniela Fanni
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Giuseppina Pichiri
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Pierpaolo Coni
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Joanna Izabela Lachowicz
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Enrico Schirru
- CeSaSASt. Centro Servizi di Ateneo per
gli Stabulari, University of Cagliari, Cagliari, Sardegna, Italy
| | - Mauro Congia
- Unit of Pediatric Gastroenterology,
Microcitemico Hospital, Cagliari, Cagliari, Sardegna, Italy
| | - Rossano Rossino
- Department of Medical Sciences and
Public Health, AOU, University of Cagliari, Cagliari, Sardegna, Italy
| | - Sandro Muntoni
- Department of Biomedical Sciences,
University of Cagliari, Cagliari, Sardegna, Italy
| | - Mariusz Jaremko
- Biological and Environmental Sciences
& Engineering Division (BESE), King Abdullah University of Science and
Technology (KAUST), Thuwal, Saudi Arabia
| | - Marco Piludu
- Department of Biomedical Sciences,
University of Cagliari, Cagliari, Sardegna, Italy,Consorzio Interuniversitario per lo
Sviluppo dei Sistemi a Grande Interfase (CSGI), Sesto Fiorentino, Italy
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Minuth WW. Concepts for a therapeutic prolongation of nephrogenesis in preterm and low-birth-weight babies must correspond to structural-functional properties in the nephrogenic zone. Mol Cell Pediatr 2017; 4:12. [PMID: 29218481 PMCID: PMC5721096 DOI: 10.1186/s40348-017-0078-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/20/2017] [Indexed: 12/30/2022] Open
Abstract
Numerous investigations are dealing with anlage of the mammalian kidney and primary development of nephrons. However, only few information is available about the last steps in kidney development leading at birth to a downregulation of morphogen activity in the nephrogenic zone and to a loss of stem cell niches aligned beyond the organ capsule. Surprisingly, these natural changes in the developmental program display similarities to processes occurring in the kidneys of preterm and low-birth-weight babies. Although those babies are born at a time with a principally intact nephrogenic zone and active niches, a high proportion of them suffers on impairment of nephrogenesis resulting in oligonephropathy, formation of atypical glomeruli, and immaturity of parenchyma. The setting points out that up to date not identified noxae in the nephrogenic zone hamper primary steps of parenchyma development. In this situation, a possible therapeutic aim is to prolong nephrogenesis by medications. However, actual data provide information that administration of drugs is problematic due to an unexpectedly complex microanatomy of the nephrogenic zone, in niches so far not considered textured extracellular matrix and peculiar contacts between mesenchymal cell projections and epithelial stem cells via tunneling nanotubes. Thus, it remains to be figured out whether disturbance of morphogen signaling altered synthesis of extracellular matrix, disturbed cell-to-cell contacts, or modified interstitial fluid impair nephrogenic activity. Due to most unanswered questions, search for eligible drugs prolonging nephrogenesis and their reliable administration is a special challenge for the future.
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Affiliation(s)
- Will W Minuth
- Institute of Anatomy, University of Regensburg, 93053, Regensburg, Germany.
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Minuth W. Reading First Coordinates from the Nephrogenic Zone in Human Fetal Kidney. Nephron Clin Pract 2017; 138:137-146. [DOI: 10.1159/000481441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 09/11/2017] [Indexed: 01/15/2023] Open
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Minuth WW, Denk L. Special Morphological Features at the Interface of the Renal Stem/Progenitor Cell Niche Force to Reinvestigate Transport of Morphogens During Nephron Induction. Biores Open Access 2016; 5:49-60. [PMID: 26862472 PMCID: PMC4744892 DOI: 10.1089/biores.2015.0039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Formation of a nephron depends on reciprocal signaling of different morphogens between epithelial and mesenchymal cells within the renal stem/progenitor cell niche. Previously, it has been surmised that a close proximity exists between both involved cell types and that morphogens are transported between them by diffusion. However, actual morphological data illustrate that mesenchymal and epithelial stem/progenitor cell bodies are separated by a striking interface. Special fixation of specimens by glutaraldehyde (GA) solution including cupromeronic blue, ruthenium red, or tannic acid for electron microscopy depicts that the interface is not void but filled in extended areas by textured extracellular matrix. Surprisingly, projections of mesenchymal cells cross the interface to contact epithelial cells. At those sites the plasma membranes of a mesenchymal and an epithelial cell are connected via tunneling nanotubes. Regarding detected morphological features in combination with involved morphogens, their transport cannot longer be explained solely by diffusion. Instead, it has to be sorted according to biophysical properties of morphogens and to detected environment. Thus, the new working hypothesis is that morphogens with good solubility such as glial cell line-derived neurotrophic factor (GDNF) or fibroblast growth factors (FGFs) are transported by diffusion. Morphogens with minor solubility such as bone morphogenetic proteins (BMPs) are secreted and stored for delivery on demand in illustrated extracellular matrix. In contrast, morphogens with poor solubility such as Wnts are transported in mesenchymal cell projections along the plasma membrane or via illustrated tunneling nanotubes. However, the presence of an intercellular route between mesenchymal and epithelial stem/progenitor cells by tunneling nanotubes also makes it possible that all morphogens are transported this way.
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Affiliation(s)
- Will W Minuth
- Department of Molecular and Cellular Anatomy, University of Regensburg , Regensburg, Germany
| | - Lucia Denk
- Department of Molecular and Cellular Anatomy, University of Regensburg , Regensburg, Germany
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Fanni D, Sanna A, Gerosa C, Puddu M, Faa G, Fanos V. Each niche has an actor: multiple stem cell niches in the preterm kidney. Ital J Pediatr 2015; 41:78. [PMID: 26472160 PMCID: PMC4608192 DOI: 10.1186/s13052-015-0187-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 10/06/2015] [Indexed: 03/13/2023] Open
Abstract
The preterm kidney cannot be simply considered as a kidney small in size: as compared to the adult kidney, the developing organ of the preterm infant is characterized by marked differences regarding the architecture and cell components. At macroscopy, fine linear demarcations indenting the renal surface characterize the fetal and preterm kidney. At microscopy, multiple major architectural changes differentiate the developing kidney from the adult one: a large capsule with a high cellularity; the branching ureteric bud, extending from the hilum towards the renal capsule; striking morphological differences among superficial (just born) and deep (more mature) glomeruli; persistence of remnants of the metanephric mesenchyme in the hylum; incomplete differentiation of developing proximal and distal tubules. At cellular level, kidneys of preterm infants are characterized by huge amounts of stem/precursor cells showing different degrees of differentiation, admixed with mature cell types. The most striking difference between the preterm and adult kidney is represented by the abundance of stem/progenitor cells in the former. Multiple stem cell niches may be identified in the preterm kidney, including the capsule, the sub-capsular nephrogenic zone, the cap mesenchyme embracing the ureteric bud tips, the cortical and medullary interstitium, and the hilar zone in proximity of the ureteric origin. The sub-capsular area represents the major stem cell niche in the prenatal kidney. It has been defined “blue strip”, due to the scarcity of cytoplasm of the undifferentiated stem/progenitors, which appear as small cells arranged in a solid pattern. All these data taken together, the morphological approach to the analysis of the preterm kidney appears completely different from that typically utilized in kidney biopsies from adult subjects. Such a different structure should be taken into account when evaluating renal function in a preterm infant in clinical practice. Moreover, a better knowledge of molecular biology of the blue strip stem/progenitor cells could be at the basis of a new “endogenous” regenerative medicine, finalized to maintain and protect the nephrogenic potential of preterm infants till the 36th week of post-conceptional age, allowing them to escape oligonephronia and chronic kidney disease later in life.
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Affiliation(s)
- D Fanni
- Department of Pathology, University of Cagliari, via Ospedale 56, 09100, Cagliari, Italy.
| | - A Sanna
- Department of Pathology, University of Cagliari, via Ospedale 56, 09100, Cagliari, Italy.
| | - C Gerosa
- Department of Pathology, University of Cagliari, via Ospedale 56, 09100, Cagliari, Italy.
| | - M Puddu
- Department of Surgery, Neonatal Intensive Care Unit, Puericulture Institute and Neonatal Section, Policlinico Monserrato, Azienda Ospedaliera Universitaria di Cagliari, University of Cagliari, 09042, Monserrato, Italy.
| | - G Faa
- Department of Pathology, University of Cagliari, via Ospedale 56, 09100, Cagliari, Italy.
| | - V Fanos
- Department of Surgery, Neonatal Intensive Care Unit, Puericulture Institute and Neonatal Section, Policlinico Monserrato, Azienda Ospedaliera Universitaria di Cagliari, University of Cagliari, 09042, Monserrato, Italy.
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Minuth WW, Denk L. Structural links between the renal stem/progenitor cell niche and the organ capsule. Histochem Cell Biol 2014; 141:459-71. [PMID: 24429831 DOI: 10.1007/s00418-014-1179-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2014] [Indexed: 11/30/2022]
Abstract
A special feature of the renal stem/progenitor cell niche is its always close neighborhood to the capsule during organ development. To explore this link, neonatal kidney was investigated by histochemistry and transmission electron microscopy. For adequate contrasting, fixation of specimens was performed by glutaraldehyde including tannic acid. The immunohistochemical data illustrate that renal stem/progenitor cells are not distributed randomly but are positioned specially to the capsule. Epithelial stem/progenitor cells are found to be enclosed by the basal lamina at a collecting duct (CD) ampulla tip. Only few layers of mesenchymal cells are detected between epithelial cells and the capsule. Most impressive, numerous microfibers reacting with soybean agglutinin, anti-collagen I and III originate from the basal lamina at a CD ampulla tip and line between mesenchymal stem/progenitor cells to the inner side of the capsule. This specific arrangement holds together both types of stem/progenitor cells in a cage and fastens the niche as a whole at the capsule. Electron microscopy further illustrates that the stem/progenitor cell niche is in contact with a tunnel system widely spreading between atypical smooth muscle cells at the inner side of the capsule. It seems probable that stem/progenitor cells are supplied here by interstitial fluid.
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Affiliation(s)
- Will W Minuth
- Molecular and Cellular Anatomy, University of Regensburg, University Street 31, 93053, Regensburg, Germany,
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Minuth WW, Denk L. The interstitial interface within the renal stem/progenitor cell niche exhibits an unique microheterogeneous composition. Int J Mol Sci 2013; 14:13657-69. [PMID: 23812083 PMCID: PMC3742209 DOI: 10.3390/ijms140713657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 06/04/2013] [Accepted: 06/18/2013] [Indexed: 12/11/2022] Open
Abstract
Repair of parenchyma by stem/progenitor cells is seen as a possible alternative to cure acute and chronic renal failure in future. To learn about this therapeutic purpose, the formation of nephrons during organ growth is under focus of present research. This process is triggered by numerous morphogenetic interactions between epithelial and mesenchymal cells within the renal stem/progenitor cell niche. Recent data demonstrate that an astonishingly wide interstitial interface separates both types of stem/progenitor cells probably controlling coordinated cell-to-cell communication. Since conventional fixation by glutaraldehyde (GA) does not declare in transmission electron microscopy the spatial separation, improved contrasting procedures were applied. As a consequence, the embryonic cortex of neonatal rabbit kidneys was fixed in solutions containing glutaraldehyde in combination with cupromeronic blue, ruthenium red or tannic acid. To obtain a comparable view to the renal stem/progenitor cell niche, the specimens had to be orientated along the cortico-medullary axis of lining collecting ducts. Analysis of tissue samples fixed with GA, in combination with cupromeronic blue, demonstrates demasked extracellular matrix. Numerous braces of proteoglycans cover, as well, the basal lamina of epithelial stem/progenitor cells as projections of mesenchymal stem/progenitor cells crossing the interstitial interface. Fixation with GA containing ruthenium red or tannic acid illustrates strands of extracellular matrix that originate from the basal lamina of epithelial stem/progenitor cells and line through the interstitial interface. Thus, for the first time, improved contrasting techniques make it possible to analyze in detail a microheterogeneous composition of the interstitial interface within the renal stem/progenitor cell niche.
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Affiliation(s)
- Will W Minuth
- Department of Molecular and Cellular Anatomy, University of Regensburg, Regensburg D-93053, Germany.
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Minuth WW, Denk L. Cell projections and extracellular matrix cross the interstitial interface within the renal stem/progenitor cell niche: accidental, structural or functional cues? Nephron Clin Pract 2013; 122:131-40. [PMID: 23735962 DOI: 10.1159/000351129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 04/03/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND During nephron induction, morphogenetic molecules are reciprocally exchanged between epithelial and mesenchymal stem/progenitor cells within the renal stem/progenitor cell niche. That these molecules remain concentrated, it is assumed that both cell populations stand in close contact to each other. However, recently published data illustrate that epithelial and mesenchymal cells are separated by an astonishingly wide interstitial interface. METHODS To gain deeper morphological insights into the spatial distribution of mesenchymal and epithelial stem/progenitor cells, the embryonic zone of neonatal rabbit kidney was fixed either with glutaraldehyde (GA) or in a combination with cupromeronic blue, ruthenium red or tannic acid. Transmission electron microscopy was then performed on exactly orientated sections. RESULTS Conventional fixation with GA illustrates that epithelial and mesenchymal stem/progenitor cells are separated by a bright but inconspicuously looking interstitial interface. In contrast, fixation of specimens in GA containing cupromeronic blue, ruthenium red or tannic acid elucidates that part of the interstitial interface exhibits a special extracellular matrix extending like woven strands between mesenchymal and epithelial stem/progenitor cells. In parallel, filigree projections from mesenchymal stem/progenitor cells cross the interstitial interface to penetrate the basal lamina of epithelial cells. Fusion of the plasma membranes cannot be observed. Instead, touching mesenchymal cell projections form a cone at the contact site with tunneling nanotubes. CONCLUSIONS The results demonstrate that the contact between mesenchymal and epithelial stem/progenitor cells does not form accidentally but physiologically and appears to belong to a suspected system involved in the exchange of morphogenetic information.
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Affiliation(s)
- Will W Minuth
- Institute for Molecular and Cellular Anatomy, University of Regensburg, Regensburg, Germany. will.minuth @ vkl.uni-regensburg.de
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