Gardnerella exposures alter bladder gene expression and augment uropathogenic Escherichia coli urinary tract infection in mice

The anaerobic actinobacteriu

An illustrated anatomical ontology of the developing mouse lower urogenital tract

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

Polyploid Superficial Cells that Maintain the Urothelial Barrier Are Produced via Incomplete Cytokinesis and Endoreplication

Summary: The urothelium is an epithelia barrier lined by a luminal layer of binucleated, octoploid, superficial cells. Superficial cells are critical for production and transport of uroplakins, a family of proteins that assemble into a waterproof crystalline plaque that helps protect against infection and toxic substances. Adult urothelium is nearly quiescent, but rapidly regenerates in response to injury. Yet the mechanism by which binucleated, polyploid, superficial cells are produced remains unclear. Here, we show that superficial cells are likely to be derived from a population of binucleated intermediate cells, which are produced from mononucleated intermediate cells via incomplete cytokinesis. We show that binucleated intermediate and superficial cells increase DNA content via endoreplication, passing through S phase without entering mitosis. The urothelium can be permanently damaged by repetitive or chronic injury or disease. Identification of the mechanism by which superficial cells are produced may be important for developing strategies for urothelial repair. : Binucleated superficial cells are critical for urothelial barrier function. Wang et al. show that they derive from binucleated intermediate cells that form via incomplete cytokinesis. Both superficial and intermediate cells increase ploidy via endoreplication, a feature likely to be important for repair and response to environmental changes. Keywords: endoreplication, urothelium, polyploidy, epithelial barrier, regeneratio

Blocking Ecm1 function alters <i>Ret</i> expression and branching.

<p>In vitro cultured kidneys from Hoxb7-GFP mice grown either in the absence (A, C, E and G) or in the presence(B, D, F and H) of the Ecm1 blocking antibody. A–D: Kidney rudiments were subjected to insitu hybridization and probed for <i>Ret</i> expression. E–H: Hoxb7-GFP kidneys showing branching of the ureteric bud tip. C and D: Arrowheads indicate the expression of <i>Ret</i> in the ub tips (C) or in the clefts (D).</p

A) Stromal cell distribution depends on <i>Ret</i> and branching.

<p>Histological sections of Foxd1-LacZ kidneys during embryonic development showing the distribution of stromal cells (blue) in the cortical region of the kidney (a–f). (a) Ampulla stage of ureteric bud (shown in pink, ureteric bud, ub) surrounded by nephron progenitor cells (pink, condensing mesenchyme, cm) and Foxd1- lacZ stromal cells (blue). (b) Growing ampulla surrounded by nephron progenitors at the tips and cleft (yellow arrow head) at the center occupied by stromal cells. (d–e) Stromal cells occupy the cleft made by the bifurcating ureteric bud tips. (f) <i>Ret</i> expression in the ureteric bud tips (white arrows). B) In vitro cultures of Hoxb7-GFP and Foxd1-GFP embryonic kidneys grown either in the presence of RA (culture beads with 10 µg/mL of RA) (a–i) or in the absence of RA (culture beads with basal media) (j–r) for 24, 48 and 72 hours. Hoxb7-GFP kidney cultures were probed for <i>Ret</i> expression after culture at 24, 48 and 72 hours (a–c and j–l). Hoxb7-GFP kidneys showing ureteric bud branching (d–f and m–o). Foxd1-GFP kidneys showing stromal cell distribution (g–i and p–r), asterisks show the ureteric buds with stromal cells around them.</p

Microarray data depicting stromal genes regulated by retinoic acid (>1.5 fold change in expression); also shown retinoic acid suppressed genes.

<p>Microarray data depicting stromal genes regulated by retinoic acid (>1.5 fold change in expression); also shown retinoic acid suppressed genes.</p

Retinoic acid controls stromal cell fate: A–F: Histological sections of wild type, <i>Rara</i>; <i>Rarb2</i> double mutant and <i>Raldh2</i> embryonic kidneys.

<p>A and B: sections of wild type kidneys showing normal distribution of the nephrons. NZ- nephrogenic zone: region under the renal capsule where continuous branching of ub and induction of nephron occurs. DZ- differentiating zone: region containing medullary stroma, differentiating nephrons and collecting duct branches. C, D and E, F: sections of <i>Rara^−/−; Rarβ^−/−</i> and <i>Raldh2</i> kidneys respectively showing reduced NZ region. In situ hybridization in cultured kidneys (G and H): <i>Foxd1LacZ</i> in vitro cultured kidneys probed for <i>Ret</i> expression. Expression of <i>FoxD1-lacZ</i> (blue) in the stromal cells of kidneys cultured in the presence of RA (G) or in the absence of RA (H) for 72 hours. Expression of <i>Ret</i> in the ureteric buds (shown in purple in G) is absent in kidneys cultured in the absence of RA (H). The expression of the stromal marker <i>Foxd1-LacZ</i> is shown in blue (G and H) in kidneys grown on RA+ or RA− media. I–L: wild type in vitro cultured kidneys; cultured in RA+ or RA− media. I and J: kidneys cultured for 24 hours and K and L kidneys cultured for 48 hours. Immunostaining with TUNEL to detect apoptotic cells (labeled in blue, I–L). Arrowheads in G and H indicate stromal cells, which are depleted in H. Arrowheads in J and L represent TUNEL positive cells which are increased in L.</p

Validation of Microarray data. Kidneys cultured in the presence of RA (A, B, C) or absence of RA (F, G, H) and subjected to in situ hybridization of the various genes.

<p>Ecm1 is dependent on retinoic acid and regulates <i>Ret</i> expression in the ureteric bud clefts. <i>Ecm1</i> expression pattern in wild type (D wholemount and E section) and <i>Raldh2</i> kidneys (I wholemount and J section).</p

Retinoid Signaling in Progenitors Controls Specification and Regeneration of the Urothelium

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

Stromal protein Ecm1 regulates ureteric bud patterning and branching

The interactions between the nephrogenic mesenchyme and the ureteric bud during kidney development are well documented. While recent studies have shed some light on the importance of the stroma during renal development, many of the signals generated in the stroma, the genetic pathways and interaction networks involving the stroma are yet to be identified. Our previous studies demonstrate that retinoids are crucial for branching of the ureteric bud and for patterning of the cortical stroma. In the present study we demonstrate that autocrine retinoic acid (RA) signaling in stromal cells is critical for their survival and patterning, and show that Extracellular matrix 1, Ecm1, a gene that in humans causes irritable bowel syndrome and lipoid proteinosis, is a novel RA-regulated target in the developing kidney, which is secreted from the cortical stromal cells surrounding the cap mesenchyme and ureteric bud. Our studies suggest that Ecm1 is required in the ureteric bud for regulating the distribution of Ret which is normally restricted to the tips, as inhibition of Ecm1 results in an expanded domain of Ret expression and reduced numbers of branches. We propose a model in which retinoid signaling in the stroma activates expression of Ecm1, which in turn down-regulates Ret expression in the ureteric bud cleft, where bifurcation normally occurs and normal branching progresses