Cathy Mendelsohn (PI)
- Ekatherina Batourina
- Tiffany Tate
- Greg Wiessner
At present there is no way to repair or regenerate the damaged urothelium. The studies proposed here are aimed at generating a molecular atlas of urothelial/stromal signaling molecules that are important for urothelial patterning in the UPJ, straight ureter, distal ureter, bladder and trigone. We propose to identify a set of markers that can be used for isolation and purification of urothelial sub-populations.
This molecular atlas will be important for developing strategies for urothelial repair and regeneration and for programming IPS cells to generate urothelial sub-populations. The urothelium is also a source of cells that give rise to bladder cancers, a group of lesions with distinct morphology and clinical behavior. Although cancer is outside the scope of NIDDK, our studies in the mouse paved the way for identification of urothelial progenitor populations that give rise to distinct bladder cancer subtypes (Van Batavia et al., 2014), a study that helps explain the diversity in clinical and morphological features observed in urothelial carcinoma in human patients.
Joseph, DB; Chandrashekar, AS; Abler, LL; Chu, LF; Thomson, JA; Mendelsohn, C; Vezina, CM. Proc Natl Acad Sci U S A. vol. 115(33), 8394–8399. August 2018.
The bladder’s remarkable regenerative capacity had been thought to derive exclusively from its own progenitors. While examining consequences of DNA methyltransferase 1 (Dnmt1) inactivation in mouse embryonic bladder epithelium, we made the surprising discovery that Wolffian duct epithelial cells can support bladder regeneration. Conditional Dnmt1 inactivation in mouse urethral and bladder epithelium triggers widespread apoptosis, depletes basal and intermediate bladder cells, and disrupts uroplakin protein expression. These events coincide with Wolffian duct epithelial cell recruitment into Dnmt1 mutant urethra and bladder where they are reprogrammed to express bladder markers, including FOXA1, keratin 5, P63, and uroplakin. This is evidence that Wolffian duct epithelial cells are summoned in vivo to replace damaged bladder epithelium and function as a reservoir of cells for bladder regeneration.
Georgas, KM; Armstrong, J; Keast, JR; Larkins, CE; McHugh, KM; Southard-Smith, EM; Cohn, MJ; Batourina, E; Dan, H; Schneider, K; Buehler, DP; Wiese, CB; Brennan, J; Davies, JA; Harding, SD; Baldock, RA; Little, MH; Vezina, CM; Mendelsohn, C. Development. vol. 142(10), 1893–908. May 2015.
Malformation of the urogenital tract represents a considerable paediatric burden, with many defects affecting the lower urinary tract (LUT), genital tubercle and associated structures. Understanding the molecular basis of such defects frequently draws on murine models. However, human anatomical terms do not always superimpose on the mouse, and the lack of accurate and standardised nomenclature is hampering the utility of such animal models. We previously developed an anatomical ontology for the murine urogenital system. Here, we present a comprehensive update of this ontology pertaining to mouse LUT, genital tubercle and associated reproductive structures (E10.5 to adult). Ontology changes were based on recently published insights into the cellular and gross anatomy of these structures, and on new analyses of epithelial cell types present in the pelvic urethra and regions of the bladder. Ontology changes include new structures, tissue layers and cell types within the LUT, external genitalia and lower reproductive structures. Representative illustrations, detailed text descriptions and molecular markers that selectively label muscle, nerves/ganglia and epithelia of the lower urogenital system are also presented. The revised ontology will be an important tool for researchers studying urogenital development/malformation in mouse models and will improve our capacity to appropriately interpret these with respect to the human situation.
Yamany, T; Van Batavia, J; Mendelsohn, C. Curr Opin Organ Transplant. vol. 19(3), 323–30. June 2014.
PURPOSE OF REVIEW: This review addresses significant changes in our understanding of urothelial development and regeneration. Understanding urothelial differentiation will be important in the push to find new methods of bladder reconstruction and augmentation, as well as identification of bladder cancer stem cells. RECENT FINDINGS: This review will cover recent findings including the identification of novel progenitor cells in the embryo and adult urothelium, function of the urothelium, and regeneration of the urothelium. Using Cre-lox recombination with cell-type-specific Cre lines, lineage studies from our laboratory have revealed novel urothelial cell types and progenitors that are critical for formation and regeneration of the urothelium. Interestingly, our studies indicate that Keratin-5-expressing basal cells, which have previously been proposed to be urothelial stem cells, are a self-renewing unipotent population, whereas P-cells, a novel urothelial cell type, are progenitors in the embryo, and intermediate cells serve as a progenitor pool in the adult. SUMMARY: These findings could have important implications for our understanding of cancer tumorigenesis and could move the fields of regeneration and reconstruction forward.
Gandhi, D; Molotkov, A; Batourina, E; Schneider, K; Dan, H; Reiley, M; Laufer, E; Metzger, D; Liang, F; Liao, Y; Sun, TT; Aronow, B; Rosen, R; Mauney, J; Adam, R; Rosselot, C; Van Batavia, J; McMahon, AP; McMahon, J; Guo, JJ; Mendelsohn, C. Dev Cell. vol. 26(5), 469–482. September 2013.
The urothelium is a multilayered epithelium that serves as a barrier between the urinary tract and blood, preventing the exchange of water and toxic substances. It consists of superficial cells specialized for synthesis and transport of uroplakins that assemble into a tough apical plaque, one or more layers of intermediate cells, and keratin 5-expressing basal cells (K5-BCs), which are considered to be progenitors in the urothelium and other specialized epithelia. Fate mapping, however, reveals that intermediate cells rather than K5-BCs are progenitors in the adult regenerating urothelium, that P cells, a transient population, are progenitors in the embryo, and that retinoids are critical in P cells and intermediate cells, respectively, for their specification during development and regeneration. These observations have important implications for tissue engineering and repair and, ultimately, may lead to treatments that prevent loss of the urothelial barrier, a major cause of voiding dysfunction and bladder pain syndrome.
Harding, SD; Armit, C; Armstrong, J; Brennan, J; Cheng, Y; Haggarty, B; Houghton, D; Lloyd-MacGilp, S; Pi, X; Roochun, Y; Sharghi, M; Tindal, C; McMahon, AP; Gottesman, B; Little, MH; Georgas, K; Aronow, B; Potter, SS; Brunskill, EW; Southard-Smith, EM; Mendelsohn, C; Baldock, RA; Davies, JA; Davidson, D. Development. vol. 138(13), 2845–53. July 2011.
The GenitoUrinary Development Molecular Anatomy Project (GUDMAP) is an international consortium working to generate gene expression data and transgenic mice. GUDMAP includes data from large-scale in situ hybridisation screens (wholemount and section) and microarray gene expression data of microdissected, laser-captured and FACS-sorted components of the developing mouse genitourinary (GU) system. These expression data are annotated using a high-resolution anatomy ontology specific to the developing murine GU system. GUDMAP data are freely accessible at www.gudmap.org via easy-to-use interfaces. This curated, high-resolution dataset serves as a powerful resource for biologists, clinicians and bioinformaticians interested in the developing urogenital system. This paper gives examples of how the data have been used to address problems in developmental biology and provides a primer for those wishing to use the database in their own research.
Little, MH; Brennan, J; Georgas, K; Davies, JA; Davidson, DR; Baldock, RA; Beverdam, A; Bertram, JF; Capel, B; Chiu, HS; Clements, D; Cullen-McEwen, L; Fleming, J; Gilbert, T; Herzlinger, D; Houghton, D; Kaufman, MH; Kleymenova, E; Koopman, PA; Lewis, AG; McMahon, AP; Mendelsohn, C; Mitchell, EK; Rumballe, BA; Sweeney, DE; Valerius, MT; Yamada, G; Yang, Y; Yu, J. Gene Expr Patterns. vol. 7(6), 680–99. June 2007.
Cataloguing gene expression during development of the genitourinary tract will increase our understanding not only of this process but also of congenital defects and disease affecting this organ system. We have developed a high-resolution ontology with which to describe the subcompartments of the developing murine genitourinary tract. This ontology incorporates what can be defined histologically and begins to encompass other structures and cell types already identified at the molecular level. The ontology is being used to annotate in situ hybridisation data generated as part of the Genitourinary Development Molecular Anatomy Project (GUDMAP), a publicly available data resource on gene and protein expression during genitourinary development. The GUDMAP ontology encompasses Theiler stage (TS) 17-27 of development as well as the sexually mature adult. It has been written as a partonomic, text-based, hierarchical ontology that, for the embryological stages, has been developed as a high-resolution expansion of the existing Edinburgh Mouse Atlas Project (EMAP) ontology. It also includes group terms for well-characterised structural and/or functional units comprising several sub-structures, such as the nephron and juxtaglomerular complex. Each term has been assigned a unique identification number. Synonyms have been used to improve the success of query searching and maintain wherever possible existing EMAP terms relating to this organ system. We describe here the principles and structure of the ontology and provide representative diagrammatic, histological, and whole mount and section RNA in situ hybridisation images to clarify the terms used within the ontology. Visual examples of how terms appear in different specimen types are also provided.