1
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Standardization of esophageal adenocarcinoma in vitro model and its applicability for model drug testing. Sci Rep 2021; 11:6664. [PMID: 33758229 PMCID: PMC7988140 DOI: 10.1038/s41598-021-85530-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/25/2021] [Indexed: 01/11/2023] Open
Abstract
FLO-1 cell line represents an important tool in esophageal adenocarcinoma (EAC) research as a verified and authentic cell line to study the disease pathophysiology and antitumor drug screenings. Since in vitro characteristics of cells depend on the microenvironment and culturing conditions, we performed a thorough characterization of the FLO-1 cell line under different culturing conditions with the aim of (1) examining the effect of serum-free growth medium and air–liquid interface (A–L) culturing, which better reflect physiological conditions in vivo and (2) investigating the differentiation potential of FLO-1 cells to mimic the properties of the in vivo esophageal epithelium. Our study shows that the composition of the media influenced the morphological, ultrastructural and molecular characteristics of FLO-1 cells, such as the expression of junctional proteins. Importantly, FLO-1 cells formed spheres at the A–L interface, recapitulating key elements of tumors in the esophageal tube, i.e., direct contact with the gas phase and three-dimensional architecture. On the other hand, FLO-1 models exhibited high permeability to model drugs and zero permeability markers, and low transepithelial resistance, and therefore poorly mimicked normal esophageal epithelium. In conclusion, the identified effect of culture conditions on the characteristics of FLO-1 cells should be considered for standardization, data reproducibility and validity of the in vitro EAC model. Moreover, the sphere-forming ability of FLO-1 cells at the A–L interface should be considered in EAC tumor biology and anticancer drug studies as a reliable and straightforward model with the potential to increase the predictive efficiency of the current in vitro approaches.
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2
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Dalghi MG, Montalbetti N, Carattino MD, Apodaca G. The Urothelium: Life in a Liquid Environment. Physiol Rev 2020; 100:1621-1705. [PMID: 32191559 PMCID: PMC7717127 DOI: 10.1152/physrev.00041.2019] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/02/2020] [Accepted: 03/14/2020] [Indexed: 02/08/2023] Open
Abstract
The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.
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Affiliation(s)
- Marianela G Dalghi
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Nicolas Montalbetti
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Marcelo D Carattino
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gerard Apodaca
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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3
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Shi J, Barakat M, Chen D, Chen L. Bicellular Tight Junctions and Wound Healing. Int J Mol Sci 2018; 19:ijms19123862. [PMID: 30518037 PMCID: PMC6321209 DOI: 10.3390/ijms19123862] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 12/15/2022] Open
Abstract
Bicellular tight junctions (TJs) are intercellular junctions comprised of a variety of transmembrane proteins including occludin, claudins, and junctional adhesion molecules (JAMs) as well as intracellular scaffold proteins such as zonula occludens (ZOs). TJs are functional, intercellular structures that form a barrier between adjacent cells, which constantly seals and unseals to control the paracellular passage of molecules. They are primarily present in the epithelial and endothelial cells of all tissues and organs. In addition to their well-recognized roles in maintaining cell polarity and barrier functions, TJs are important regulators of signal transduction, which modulates cell proliferation, migration, and differentiation, as well as some components of the immune response and homeostasis. A vast breadth of research data is available on TJs, but little has been done to decipher their specific roles in wound healing, despite their primary distribution in epithelial and endothelial cells, which are essential contributors to the wound healing process. Some data exists to indicate that a better understanding of the functions and significance of TJs in healing wounds may prove crucial for future improvements in wound healing research and therapy. Specifically, recent studies demonstrate that occludin and claudin-1, which are two TJ component proteins, are present in migrating epithelial cells at the wound edge but are absent in chronic wounds. This indicates that functional TJs may be critical for effective wound healing. A tremendous amount of work is needed to investigate their roles in barrier function, re-epithelialization, angiogenesis, scar formation, and in the interactions between epithelial cells, endothelial cells, and immune cells both in the acute wound healing process and in non-healing wounds. A more thorough understanding of TJs in wound healing may shed new light on potential research targets and reveal novel strategies to enhance tissue regeneration and improve wound repair.
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Affiliation(s)
- Junhe Shi
- Center for Wound Healing and Tissue Regeneration, College of Dentistry, University of Illinois at Chicago, 801 S. Paulina Street, Chicago, IL 60612, USA.
| | - May Barakat
- Center for Wound Healing and Tissue Regeneration, College of Dentistry, University of Illinois at Chicago, 801 S. Paulina Street, Chicago, IL 60612, USA.
| | - Dandan Chen
- Colgate-Palmolive Company, Piscataway, NJ 08855, USA.
| | - Lin Chen
- Center for Wound Healing and Tissue Regeneration, College of Dentistry, University of Illinois at Chicago, 801 S. Paulina Street, Chicago, IL 60612, USA.
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4
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Jerman UD, Kreft ME. Reuse of bladder mucosa explants provides a long lasting source of urothelial cells for the establishment of differentiated urothelia. Histochem Cell Biol 2018; 150:567-574. [PMID: 30094468 DOI: 10.1007/s00418-018-1704-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2018] [Indexed: 12/31/2022]
Abstract
Organ explant cultures are well-established in vitro models that are used to study normal cell biological and regeneration processes as well as carcinogenesis. Primary urothelial cultures from bladder mucosa explants are highly differentiated and are thus broadly used as in vitro experimental equivalents of native urothelial tissue. Since experiments on differentiated urothelial cultures from bladder mucosa explants currently allow only a single use of explants, establishment of sufficient quantities of cultures requires large numbers of sacrificed animals. There is thus a great need for a cheaper approach with less ethical dilemmas. Herein, we demonstrate that mouse bladder mucosa explants can be reused. Reused explants produce outgrowths with highly differentiated urothelia, just like primary explants. Even after being recycled ten times, urothelial outgrowths have the supramolecular and ultrastructural features that are comparable to the native urothelium. Ten times reused explants produce superficial urothelial cells that express uroplakins in the apical plasma membrane, claudin-8 in the tight junctions, and have a subapical network of cytokeratin 20. Basal urothelial cells in urothelial outgrowths of ten times reused explants express p63 which indicates that these urothelial outgrowths have a persistent proliferative capacity. Using our approach, one can perform experiments that were previously not feasible due to low quantities of donor tissue. The method also offers opportunity for effective use of scarce healthy human urothelial tissue.
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Affiliation(s)
- Urška Dragin Jerman
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia
| | - Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia.
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5
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Zupančič D, Mrak Poljšak K, Kreft ME. Co-culturing porcine normal urothelial cells, urinary bladder fibroblasts and smooth muscle cells for tissue engineering research. Cell Biol Int 2017; 42:411-424. [PMID: 29115705 DOI: 10.1002/cbin.10910] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/05/2017] [Indexed: 12/27/2022]
Abstract
New strategies for culturing and co-culturing of the main types of urinary bladder cells are essential for successful establishment of biomimetic in vitro models, which could be applied for research into, and management of, diverse urological disorders. Porcine normal urothelial cells are available in nearly unlimited amounts and have many properties equivalent to human urothelial cells. In the present study, we established normal differentiated porcine urothelial cells in co-cultures with porcine urinary bladder normal fibroblasts and/or smooth muscle cells. The optimal culture medium for establishment of differentiated urothelial cells, demonstrated by positive immunofluorescence of uroplakins, cytokeratins (CK 7, CK 20), zonula occludens 1 (ZO-1), claudin 4, claudin 8, and E-cadherin, was the medium composed of equal parts of Advanced Dulbecco's modified Eagle's medium (A-DMEM) and MCDB 153 medium with physiological calcium concentration of 2.5 mM and without fetal bovine serum, named UroM (+Ca2+ - S). This medium was also proven to be suitable for culturing of bladder fibroblasts and smooth muscle cells and co-culturing of urothelial cells with these mesenchymal cells. Urothelial cell differentiation was optimal in UroM (+Ca2+ - S) medium in all co-culture conditions and when compared to all conditioned-media combinations. To summarize, these strategies for culturing and co-culturing of urinary bladder urothelial cells with mesenchymal cells could be used as new in vitro models for future basic and applicable research of the urinary bladder and thus potentially also for translational tissue engineering studies.
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Affiliation(s)
- Daša Zupančič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Katjuša Mrak Poljšak
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
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6
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Volksdorf T, Heilmann J, Eming SA, Schawjinski K, Zorn-Kruppa M, Ueck C, Vidal-Y-Sy S, Windhorst S, Jücker M, Moll I, Brandner JM. Tight Junction Proteins Claudin-1 and Occludin Are Important for Cutaneous Wound Healing. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1301-1312. [PMID: 28412298 DOI: 10.1016/j.ajpath.2017.02.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/07/2017] [Indexed: 12/31/2022]
Abstract
Tight junction (TJ) proteins are known to be involved in proliferation and differentiation. These processes are essential for normal skin wound healing. Here, we investigated the TJ proteins claudin-1 and occludin in ex vivo skin wound healing models and tissue samples of acute and chronic human wounds and observed major differences in localization/expression of these proteins, with chronic wounds often showing a loss of the proteins at the wound margins and/or in the regenerating epidermis. Knockdown experiments in primary human keratinocytes showed that decreased claudin-1 expression resulted in significantly impaired scratch wound healing, with delayed migration and reduced proliferation. Activation of AKT pathway was significantly attenuated after claudin-1 knockdown, and protein levels of extracellular signal-related kinase 1/2 were reduced. For occludin, down-regulation had no impact on wound healing in normal scratch assays, but after subjecting the cells to mechanical stress, which is normally present in wounds, wound healing was impaired. For both proteins we show that most of these actions are independent from the formation of barrier-forming TJ structures, thus demonstrating nonbarrier-related functions of TJ proteins in the skin. However, for claudin-1 effects on scratch wound healing were more pronounced when TJs could form. Together, our findings provide evidence for a role of claudin-1 and occludin in epidermal regeneration with potential clinical importance.
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Affiliation(s)
- Thomas Volksdorf
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Janina Heilmann
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Sabine A Eming
- Department of Dermatology, University of Cologne, Cologne, Germany
| | - Kathrin Schawjinski
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Michaela Zorn-Kruppa
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Christopher Ueck
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Sabine Vidal-Y-Sy
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Sabine Windhorst
- Institute of Biochemistry and Signal Transduction, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Moll
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Johanna M Brandner
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
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7
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Imani R, Pazoki M, Zupančič D, Kreft ME, Kralj-Iglič V, Veranič P, Iglič A. Biocompatibility of different nanostructured TiO 2 scaffolds and their potential for urologic applications. PROTOPLASMA 2016; 253:1439-1447. [PMID: 26497540 DOI: 10.1007/s00709-015-0896-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
Despite great efforts in tissue engineering of the ureter, urinary bladder, and urethra, further research is needed in order to improve the patient's quality of life and minimize the economic burden of different lower urinary tract disorders. The nanostructured titanium dioxide (TiO2) scaffolds have a wide range of clinical applications and are already widely used in orthopedic or dental medicine. The current study was conducted to synthesize TiO2 nanotubes by the anodization method and TiO2 nanowires and nanospheres by the chemical vapor deposition method. These scaffolds were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. In order to test the urologic applicability of generated TiO2 scaffolds, we seeded the normal porcine urothelial (NPU) cells on TiO2 nanotubes, TiO2 nanowires, TiO2 nanospheres, and on the standard porous membrane. The viability and growth of the cells were monitored everyday, and after 3 weeks of culturing, the analysis with scanning electron microscope (SEM) was performed. Our results showed that the NPU cells were attached on all scaffolds; they were viable and formed a multilayered epithelium, i.e., urothelium. The apical plasma membrane of the majority of superficial NPU cells, grown on all three different TiO2 scaffolds and on the porous membrane, exhibited microvilli; thus, indicating that they were at a similar differentiation stage. The maximal caliper diameter measurements of superficial NPU cells revealed significant alterations, with the largest cells being observed on nanowires and the smallest ones on the porous membrane. Our findings indicate that different nanostructured TiO2 scaffolds, especially nanowires, have a great potential for tissue engineering and should be further investigated for various urologic applications.
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Affiliation(s)
- Roghayeh Imani
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, Ljubljana, Slovenia
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena 5, Ljubljana, Slovenia
| | - Meysam Pazoki
- Department of Chemistry, Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 75120, Uppsala, Sweden
| | - Daša Zupančič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana, Slovenia
| | - Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana, Slovenia
| | - Veronika Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena 5, Ljubljana, Slovenia
| | - Peter Veranič
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, Ljubljana, Slovenia.
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8
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Papafotiou G, Paraskevopoulou V, Vasilaki E, Kanaki Z, Paschalidis N, Klinakis A. KRT14 marks a subpopulation of bladder basal cells with pivotal role in regeneration and tumorigenesis. Nat Commun 2016; 7:11914. [PMID: 27320313 PMCID: PMC4915139 DOI: 10.1038/ncomms11914] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 05/10/2016] [Indexed: 01/20/2023] Open
Abstract
The urothelium is a specialized epithelium that lines the urinary tract. It consists of three different cell types, namely, basal, intermediate and superficial cells arranged in relatively distinct cell layers. Normally, quiescent, it regenerates fast upon injury, but the regeneration process is not fully understood. Although several reports have indicated the existence of progenitors, their identity and exact topology, as well as their role in key processes such as tissue regeneration and carcinogenesis have not been clarified. Here we show that a minor subpopulation of basal cells, characterized by the expression of keratin 14, possesses self-renewal capacity and also gives rise to all cell types of the urothelium during natural and injury-induced regeneration. Moreover, these cells represent cells of origin of urothelial cancer. Our findings support the hypothesis of basally located progenitors with profound roles in urothelial homoeostasis.
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Affiliation(s)
- George Papafotiou
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Varvara Paraskevopoulou
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Eleni Vasilaki
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Zoi Kanaki
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Nikolaos Paschalidis
- Laboratory of Cellular Immunology, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Apostolos Klinakis
- Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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9
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Lasič E, Višnjar T, Kreft ME. Properties of the Urothelium that Establish the Blood–Urine Barrier and Their Implications for Drug Delivery. Rev Physiol Biochem Pharmacol 2015; 168:1-29. [DOI: 10.1007/112_2015_22] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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10
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The complete functional recovery of chitosan-treated biomimetic hyperplastic and normoplastic urothelial models. Histochem Cell Biol 2014; 143:95-107. [PMID: 25161121 DOI: 10.1007/s00418-014-1265-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
Abstract
The urinary tract is exposed to a variety of possible injures that may lead to organ damage or loss, and thus, the establishment of valid in vitro urothelial models to study the mechanism of drug candidates is necessary. This study is the first to investigate the effect of chitosan on urothelia in vitro and to evaluate whether chitosan-treated urothelial models can regenerate in vitro and reestablish a functional urothelium. Biomimetic hyperplastic and normoplastic urothelial models were used to test the effect of chitosan (0.05%) on partially and highly differentiated urothelial cells (UCs) by monitoring their molecular, ultrastructural, and physiological changes for 3 weeks. Chitosan caused an immediate and complete loss of transepithelial resistance (TER), tight junction disruption, cytopathological changes of UCs, and consequently enhanced the permeability of partially and highly differentiated urothelial models. However, 3 weeks after chitosan treatment, TER was reestablished, tight junctions resealed, permeability decreased, and progressive differentiation stages of newly exposed superficial UCs expressing uroplakins and tight junction protein claudin-8 were found. The in vitro models regenerated and reestablished urothelia with a tight barrier. The biomimetic urothelial models represent appropriate in vitro models for studying urothelial drug candidates as well as evaluating drug permeabilities and their intracellular function. Understanding the possible intracellular function of chitosan could significantly advance approaches to treating urothelial-specific diseases.
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11
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Višnjar T, Kreft ME. Air-liquid and liquid-liquid interfaces influence the formation of the urothelial permeability barrier in vitro. In Vitro Cell Dev Biol Anim 2013; 49:196-204. [PMID: 23408058 DOI: 10.1007/s11626-013-9585-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 01/25/2013] [Indexed: 12/31/2022]
Abstract
Optimizing culture conditions is known to be crucial for the differentiation of urothelial cell cultures and the formation of the permeability barrier. However, so far, no data exist to confirm if air-liquid (AL) and liquid-liquid (LL) interfaces are physiologically relevant during urothelial differentiation and barrier formation. To reveal the influence of interfaces on the proliferation, differentiation, and barrier formation of the urothelial cells (UCs) in vitro, we cultured UCs under four different conditions, i.e., at the AL or LL interfaces with physiological calcium concentration and without serum or without physiological calcium concentration and with serum. For each of the four models, the urothelial integrity was tested by measuring the transepithelial resistance (TER), and the differentiation stage was examined by immunolabeling of differentiation-related markers and ultrastructural analysis. We found that the UCs at a LL interface, regardless of the presence or absence of calcium or serum, form the urothelium with more cell layers and achieve a higher TER than UCs at an AL interface. However, UCs grown at an AL interface with physiological concentration of calcium in medium form only one- to two-layered urothelium of UCs, which are larger and express more differentiation-related proteins uroplakins than UCs in other models. These results demonstrate that the interface itself can play a major, although so-far neglected, role in urothelial physiology, particularly in the formation of the urothelial permeability barrier in vitro and the regulatory mechanisms related with urothelial differentiation. In the study, the culturing of UCs in three successive steps is proposed.
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Affiliation(s)
- Tanja Višnjar
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Lipičeva 2, 1000, Ljubljana, Slovenia
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12
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Abstract
The alveolar epithelium of the lung constitutes a unique interface with the outside environment. This thin barrier must maintain a surface for gas transfer while being continuously exposed to potentially hazardous environmental stimuli. Small differences in alveolar epithelial barrier properties could therefore have a large impact on disease susceptibility or outcome. Moreover, recent work has focused attention on the alveolar epithelium as central to several lung diseases, including acute lung injury and idiopathic pulmonary fibrosis. Although relatively little is known about the function and regulation of claudin tight junction proteins in the lung, new evidence suggests that environmental stimuli can influence claudin expression and alveolar barrier function in human disease. This review considers recent advances in the understanding of the role of claudins in the breakdown of the alveolar epithelial barrier in disease and in epithelial repair.
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Affiliation(s)
- James A Frank
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, USA.
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13
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Kreft ME, Robenek H. Freeze-fracture replica immunolabelling reveals urothelial plaques in cultured urothelial cells. PLoS One 2012; 7:e38509. [PMID: 22768045 PMCID: PMC3387185 DOI: 10.1371/journal.pone.0038509] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 05/07/2012] [Indexed: 12/02/2022] Open
Abstract
The primary function of the urothelium is to provide the tightest and most impermeable barrier in the body, i.e. the blood-urine barrier. Urothelial plaques are formed and inserted into the apical plasma membrane during advanced stages of urothelial cell differentiation. Currently, it is supposed that differentiation with the final formation of urothelial plaques is hindered in cultured urothelial cells. With the aid of the high-resolution imaging technique of freeze-fracture replica immunolabelling, we here provide evidence that urothelial cells in vitro form uroplakin-positive urothelial plaques, localized in fusiform-shaped vesicles and apical plasma membranes. With the establishment of such an in vitro model of urothelial cells with fully developed urothelial plaques and functional properties equivalent to normal bladder urothelium, new perspectives have emerged which challenge prevailing concepts of apical plasma membrane biogenesis and blood-urine barrier development. This may hopefully provide a timely impulse for many ongoing studies and open up new questions for future research.
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Affiliation(s)
- Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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14
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Višnjar T, Kocbek P, Kreft ME. Hyperplasia as a mechanism for rapid resealing urothelial injuries and maintaining high transepithelial resistance. Histochem Cell Biol 2011; 137:177-86. [PMID: 22127649 DOI: 10.1007/s00418-011-0893-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2011] [Indexed: 01/01/2023]
Abstract
When the urothelial barrier, i.e., the blood-urine barrier, is injured, rapid resealing of the injury is crucial for the normal functioning of the organism. In order to investigate the mechanisms required for rapid resealing of the barrier, we established in vitro models of hyperplastic and normoplastic urothelia. We found that hyperplastic urothelia achieve significantly higher transepithelial resistance (TER) than normoplastic urothelia. However, the expression of cell junctional (claudin-8, occludin, E-cadherin) and differentiation-related proteins (cytokeratin 20 and uroplakins) is weaker in hyperplastic urothelia. Further investigation of cell differentiation status at the ultrastructural level confirmed that superficial urothelial cells (UCs) in hyperplastic urothelial models achieve a lower differentiation stage than superficial UCs in normoplastic urothelial models. With the establishment of such in vitro models and the aid of TER measurements, flow cytometry, molecular and ultrastructural analysis, we here provide unequivocal evidence that the specific cell-cycle distribution and, consequently, the number of cell layers have a significant influence on the barrier function of urothelia. We demonstrate the importance of hyperplasia for the rapid restoration of the urothelial barrier and the maintenance of high TER until the UCs reach a highly differentiated stage and restoration of the urothelial barrier after injury is complete. The information that this approach provides is unique and we expect that further exploitation of hyperplastic and normoplastic urothelial models in future studies may advance our understanding of blood-urine barrier development and functionality.
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Affiliation(s)
- Tanja Višnjar
- Institute of Cell Biology, University of Ljubljana, Ljubljana, Slovenia
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Zupančič D, Ovčak Z, Vidmar G, Romih R. Altered expression of UPIa, UPIb, UPII, and UPIIIa during urothelial carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine in rats. Virchows Arch 2011; 458:603-13. [PMID: 21301865 DOI: 10.1007/s00428-011-1045-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Revised: 12/21/2010] [Accepted: 01/10/2011] [Indexed: 12/11/2022]
Abstract
In normal urothelium, superficial umbrella cells express four major integral membrane proteins, uroplakins UPIa, UPIb, UPII, and UPIIIa, which compose urothelial plaques. In the apical plasma membrane, urothelial plaques form microridges. During neoplastic changes, microridges are replaced by microvilli, while uroplakin expression is retained. We correlated individual uroplakin expression with apical plasma membrane structure, cytokeratin 20 expression, and urothelial cell proliferation (Ki-67). Male Wistar rats were treated with 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in drinking water, which caused flat hyperplasia with mild dysplasia, low-grade papillary urothelial carcinoma, invasive low- and high-grade papillary urothelial carcinoma and invasive squamous cell carcinoma with extensive keratinization, grade 2. During urothelial carcinogenesis, UPII expression was the most decreased in all urothelial lesions, while UPIa, UPIb, and UPIIIa expression was differently altered in different types of lesions. Superficial cells were covered with microvilli and ropy ridges, while microridges were disappearing. The expression of cytokeratin 20 was decreased and limited to superficial urothelial cells. Proliferation indices were increased, except for invasive squamous cell carcinoma with extensive keratinization. Our results indicate that during urothelial carcinogenesis the expression of UPII is diminished, suggesting that UPIb/UPIIIa heterodimer can still be formed, while heterodimer UPIa/UPII formation is disrupted. Correlation between decreased level of UPII expression and changed apical plasma membrane structure suggests that diminished expression of UPII hinders the urothelial plaque formation.
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Affiliation(s)
- Daša Zupančič
- Institute of Cell Biology, Faculty of Medicine, Lipičeva 2, Ljubljana, Slovenia.
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16
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Kreft ME, Hudoklin S, Jezernik K, Romih R. Formation and maintenance of blood-urine barrier in urothelium. PROTOPLASMA 2010; 246:3-14. [PMID: 20521071 DOI: 10.1007/s00709-010-0112-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 01/15/2010] [Indexed: 05/29/2023]
Abstract
Blood-urine barrier, which is formed during differentiation of superficial urothelial cells, is the tightest and most impermeable barrier in the body. In the urinary bladder, the barrier must accommodate large changes in the surface area during distensions and contractions of the organ. Tight junctions and unique apical plasma membrane of superficial urothelial cells play a critical role in the barrier maintenance. Alterations in the blood-urine barrier function accompany most of the urinary tract diseases. In this review, we discuss recent discoveries on the role of tight junctions, dynamics of Golgi apparatus and post-Golgi compartments, and intracellular membrane traffic during the biogenesis and maintenance of blood-urine barrier.
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Affiliation(s)
- Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Lipiceva 2, SI-1000, Ljubljana, Slovenia.
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17
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Wolters HH, Heistermann HP, Stöppeler S, Hierlemann H, Spiegel HU, Palmes D. A New Technique for Ureteral Defect Lesion Reconstruction Using an Autologous Vein Graft and a Biodegradable Endoluminal Stent. J Urol 2010; 184:1197-203. [DOI: 10.1016/j.juro.2010.04.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Indexed: 12/22/2022]
Affiliation(s)
- Heiner H. Wolters
- Department of General and Visceral Surgery, Muenster University Hospital, Muenster, Germany
| | | | - Sandra Stöppeler
- Surgical Research, Muenster University Hospital, Muenster, Germany
| | - Helmut Hierlemann
- Institute of Textile Technology and Process Engineering, Denkendorf, Germany
| | | | - Daniel Palmes
- Department of General and Visceral Surgery, Muenster University Hospital, Muenster, Germany
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18
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Kreft ME, Jezernik K, Kreft M, Romih R. Apical plasma membrane traffic in superficial cells of bladder urothelium. Ann N Y Acad Sci 2009; 1152:18-29. [PMID: 19161373 DOI: 10.1111/j.1749-6632.2008.04004.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Superficial urothelial cells that line the urinary bladder accommodate cyclical changes in organ volume while maintaining a permeability barrier between urine and tissue fluids. The specific apical plasma membrane traffic is necessary for their proper function. The composition of the apical plasma membrane is dramatically modified during differentiation of bladder urothelial cells, most notably by assembly of urothelial plaques containing uroplakins. However, the assembly of uroplakins into plaques, their insertion and removal from the apical surface, and the regulation of these processes are still poorly understood. This review examines the traffic (exocytosis/endocytosis) of the apical plasma membrane during differentiation of urothelial cells and focuses on the physiological and clinical significance of the apical plasma membrane traffic in bladder superficial urothelial cells.
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Affiliation(s)
- Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
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19
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Kreft ME, Romih R, Kreft M, Jezernik K. Endocytotic activity of bladder superficial urothelial cells is inversely related to their differentiation stage. Differentiation 2008; 77:48-59. [PMID: 19281764 DOI: 10.1016/j.diff.2008.09.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 05/27/2008] [Accepted: 07/12/2008] [Indexed: 12/20/2022]
Abstract
The composition of the apical plasma membrane of bladder superficial urothelial cells is dramatically modified during cell differentiation, which is accompanied by the change in the dynamics of endocytosis. We studied the expression of urothelial differentiation-related proteins uroplakins and consequently the apical plasma membrane molecular composition in relation to the membrane-bound and fluid-phase endocytosis in bladder superficial urothelial cells. By using primary urothelial cultures in the environment without mechanical stimuli, we studied the constitutive endocytosis. Four new findings emerge from our study. First, in highly differentiated superficial urothelial cells with strong uroplakin expression, the endocytosis of fluid-phase endocytotic markers was 43% lower and the endocytosis of membrane-bound markers was 86% lower compared to partially differentiated cells with weak uroplakin expression. Second, superficial urothelial cells have 5-15-times lower endocytotic activity than MDCK cells. Third, in superficial urothelial cells the membrane-bound markers are delivered to lysosomes, while fluid-phase markers are seen only in early endocytotic compartments, suggesting their kiss-and-run recycling. Finally, we provide the first evidence that in highly differentiated cells the uroplakin-positive membrane regions are excluded from internalization, suggesting that uroplakins hinder endocytosis from the apical plasma membrane in superficial urothelial cells and thus maintain optimal permeability barrier function.
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Affiliation(s)
- Mateja Erdani Kreft
- Institute of Cell Biology, Faculty of Medicine, University of Ljubljana, Lipiceva 2, SI-1000 Ljubljana, Slovenia.
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20
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Abstract
The progress in discerning the structure and function of cells and tissues in health and disease has been achieved to a large extent by the continued development of new reagents for histochemistry, the improvement of existing techniques and new imaging techniques. This review will highlight some advancements made in these fields.
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Taatjes DJ, Zuber C, Roth J. The histochemistry and cell biology vade mecum: a review of 2005–2006. Histochem Cell Biol 2006; 126:743-88. [PMID: 17149649 DOI: 10.1007/s00418-006-0253-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2006] [Indexed: 02/07/2023]
Abstract
The procurement of new knowledge and understanding in the ever expanding discipline of cell biology continues to advance at a breakneck pace. The progress in discerning the physiology of cells and tissues in health and disease has been driven to a large extent by the continued development of new probes and imaging techniques. The recent introduction of semi-conductor quantum dots as stable, specific markers for both fluorescence light microscopy and electron microscopy, as well as a virtual treasure-trove of new fluorescent proteins, has in conjunction with newly introduced spectral imaging systems, opened vistas into the seemingly unlimited possibilities for experimental design. Although it oftentimes proves difficult to predict what the future will hold with respect to advances in disciplines such as cell biology and histochemistry, it is facile to look back on what has already occurred. In this spirit, this review will highlight some advancements made in these areas in the past 2 years.
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Affiliation(s)
- Douglas J Taatjes
- Department of Pathology, Microscopy Imaging Center, College of Medicine, University of Vermont, Burlington, VT 05405, USA.
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