Project description:The kidney and bladder expresses a variety of powerful defense mechanisms to limit urinary infection including iron scavenging, a process called "nutritional immunity". We previously demonstrated that bladder and kidney epithelia generates the archetype of the urinary iron defense, a lipocalin called NGAL which binds Enterochelin, a bacterial siderophore. However, because urinary bacteria can evade the bacteriostatic effects of NGAL by modifying Enterochelin and by producing additional siderophores, other mechanisms of "nutritional immunity" are anticipated. To study the defense in the kidney, we used a cell type specific method of RNA isolation in mouse (adapted from Gay et al, Oregon). A promiscuous form of phosphoribosyltransferase (UPRT) was cloned into the Rosa26 locus using a floxed-stop design which we activated in a cell specific fashion with Atp6v1b1-Cre. Thiouracil was introduced 12hr and 24hrs after urinary tract infection. Isolation of RNA directly from intercalated revealed synthetic (Npas1-Bmal1-Alas), transport (Hrg1, Flvcr1) and metabolic enzymes (Hmox1) of heme metabolism. Hmox1 was detected in the kidney with a luciferase based reporter (Contag et al, Stanford) after infection. CO production was detected in vivo and in AtpCre-mTmG FACS isolated intercalated cells in vitro using a novel metal-based probe synthesized at Columbia (adapted from Liu et al, China). Urinary bacteria (UPEC) with heme transport mutations were not competitive in the colonization of the kidney but conversely were markedly stimulated by iron, suggesting bacterial-host competition for heme capture and metabolism. In fact, infection upregulated both heme synthetic and metabolic genes, suggesting that CO production is induced by infection. Exposure to CO terminated the growth of UPEC. In sum, we have identified an unusual iron trafficking system in the collecting ducts that mirrors the nutritional requirements of UPEC to achieve pyelonephritis. Many of these components are specific to the intercalated cells, consistent with the notion that these cells defend the urinary tract from infection.
Project description:Peroxisome Proliferator-Activated Receptor-gamma (PPARG) is a nuclear hormone receptor that was originally described as a master regulator of adipogenesis but could also promote cellular differentiation in a number of epithelium. PPARG also serves as an important regulator in anti-inflammatory activity after a variety of injuries, acting in part by antagonizing the NF-kB pathway. Moreover, the expression of PPARG is strongly down regulated in the basal subtype of bladder cancer, suggesting that its removal might be essential in tumorigenesis. In urothelial cells, it has been shown that PPARG promotes urothelial differentiation in vitro, but its function in vivo remains unexplored. The urothelium is a stratified epithelium that serves as a barrier between the urinary tract and blood. It consists of terminally differentiated umbrella cells, intermediate cells which serve as umbrella cell progenitors; and unipotent basal cells. To determine the role of PPARG in vivo, we used Cre-Lox recombination to conditionally delete the Pparg gene in the mouse urothelium using the ShhCre driver, which drives recombination in basal and intermediate cells, and their respective daughters. Interestingly, ShhCre;Ppargfl/fl mutants lack umbrella and intermediate cells, but have an abnormal cell population negative for classical urothelial markers instead. Furthermore, we observed an increase of KRT14+ population in the basal compartment and squamous features in the mutant urothelium. Expression profile analysis suggested PPARG regulates metabolism, urothelial differentiation and innate immune response. We further challenged the Pparg mutant urothelium with acute injury. In wild type animals, urinary tract infection (UTI) with uropathogenic E.coli results in a transient innate immune response, followed by a completed regernation within 2 weeks. When ShhCre;Ppargfl/fl mutants were challenged with urinary tract infection, the innate immune response was not resolved even after several weeks and the Pparg ablated urothelium exhibited squamous metaplasia. RNAseq data suggested that PPARG plays a role in regulating squmous differentiation and NFkB signial pathway. Together these findings suggest that PPARG is essential for the normal differentiation of the urothelium and is a potent regulator of the inflammatory response after UTI. Understanding the link between the loss of PPARG, chronic inflammation and tumorigenesis in the urothelium could shed light on the urothelial differentiation network and pave the way for the development of therapeutic approaches to various urinary diseases.
Project description:Bilateral freezing of the pelvic ganglia in female rats were performed to denervate the urinary bladder. Sham operated rats were used as controls. The rats were sacrificed 10 days after surgery. The urinary bladders (including the urothelium) were frozen and used for RNA extraction.
Project description:Bilateral freezing of the pelvic ganglia in female rats were performed to denervate the urinary bladder. Sham operated rats were used as controls. The rats were sacrificed 10 days after surgery. The urinary bladders (including the urothelium) were frozen and used for RNA extraction.
Project description:Overactive bladder (OAB) syndrome is a condition that has four symptoms: urgency, urinary frequency, nocturia, and urge incontinence and negatively affects a patient’s life. Recently, it is considered that the urinary bladder urothelium is closely linked to pathogenesis of OAB. However, the mechanisms of pathogenesis of OAB at the molecular level remain poorly understood, mainly as a result of lack of modern molecular analysis. The goal of this study is to identify a potential target protein that could act as a predictive factor for effective diagnosis and aid in the development of therapeutic strategies for the treatment of OAB syndrome. We produced OAB in a rat model and performed the first proteomic analysis on the mucosal layer (urothelium) of the bladders of normal and OAB rats.
Project description:Scientific evidence suggests that not only murine scent communication is regulated by major urinary proteins, but that their expression may also vary in response to metabolism via a yet unknown mechanism. Major urinary proteins are expressed mainly in the liver, showing a sexually dimorphic pattern with substantially higher expression in males. Here, we investigate the metabolic implications of a major urinary protein knockout in twelve-week-old male and female C57BL/6N mice during ad libitum feeding. Despite both sexes of major urinary protein knockout mice displayed numerically increased body weight and visceral adipose tissue proportions compared to sex-matched wildtype mice, the main genotype-specific metabolic differences were observed exclusively in males. Male major urinary protein knockout mice exhibited plasma and hepatic lipid accumulation accompanied by a hepatic transcriptome indicating an activation of lipogenesis. These findings match the higher major urinary protein expression in male compared to female wildtype mice, suggesting a more distinct reduction in energy requirements in male compared to female major urinary protein knockout mice. The observed sex-specific anabolic phenotype confirms a role of major urinary protein in metabolism and, since major urinary proteins are not expressed in humans, suggests the major urinary protein knockout mouse as a potential alternative model for translational metabolism research which needs to be further elucidated.
Project description:Scientific evidence suggests that not only murine scent communication is regulated by major urinary proteins, but that their expression may also vary in response to metabolism via a yet unknown mechanism. Major urinary proteins are expressed mainly in the liver, showing a sexually dimorphic pattern with substantially higher expression in males. Here, we investigate the metabolic implications of a major urinary protein knockout in twelve-week-old male and female C57BL/6N mice during ad libitum feeding. Despite both sexes of major urinary protein knockout mice displayed numerically increased body weight and visceral adipose tissue proportions compared to sex-matched wildtype mice, the main genotype-specific metabolic differences were observed exclusively in males. Male major urinary protein knockout mice exhibited plasma and hepatic lipid accumulation accompanied by a hepatic transcriptome indicating an activation of lipogenesis. These findings match the higher major urinary protein expression in male compared to female wildtype mice, suggesting a more distinct reduction in energy requirements in male compared to female major urinary protein knockout mice. The observed sex-specific anabolic phenotype confirms a role of major urinary protein in metabolism and, since major urinary proteins are not expressed in humans, suggests the major urinary protein knockout mouse as a potential alternative model for translational metabolism research which needs to be further elucidated.
Project description:Urothelium forms a distensible yet impermeable barrier, senses and transduces stimuli, and defends the urinary tract from mechanical, chemical and bacterial injuries. Biochemical and genetic labeling studies support the existence of one or more progenitor populations with the capacity to rapidly regenerate the urothelium following injury, but slow turnover, a low mitotic index, and inconsistent methodologies obscure progenitor identity. The progenitor properties of basal Keratin 5 urothelial cells (K5-UC) have been previously investigated, but those studies focused on embryonic or adult bladder urothelium. Urothelium undergoes desquamation and apoptosis after birth, which requires postnatal proliferation and restoration. Therefore, we mapped the fate of bladder K5-UCs across postnatal development/maturation and following administration of cyclophosphamide to measure homeostatic and reparative progenitor capacities, respectively. In vivo studies demonstrate that basal K5-UCs are age-restricted progenitors in neonates and juveniles, but not in adult mice. Neonatal K5-UCs retain a superior progenitor capacity in vitro, forming larger and more differentiated urothelial organoids than adult K5-UCs. Accordingly, K5-UC transcriptomes are temporally distinct, with enrichment of transcripts associated with cell proliferation and differentiation in neonates. Induction of urothelial proliferation is sufficient to restore adult K5-UC progenitor capacity. Our findings advance the understanding of urothelial progenitors and support a linear model of urothelial formation and regeneration, which may have significant impact on therapeutic development or tissue engineering strategies.
Project description:Objectives: Much of the information to date in terms of subtypes and function of bladder urothelial cells were derived from anatomical location or by the expression of a small number of marker genes. To have a comprehensive map of the cellular anatomy of bladder urothelial cells, we performed single-cell RNA-sequencing to thoroughly characterize mouse bladder urothelium. Materials and methods: A total of 18,917 single cells from mouse bladder urothelium was analyzed by unbiased single-cell RNA sequencing. The expression of the novel cell marker was confirmed by immunofluorescence using urinary tract infections models. Results: Unsupervised clustering analysis identified 8 transcriptionally distinct cell subpopulations from mouse bladder urothelial cells. We discovered a novel type of bladder urothelial cells marked by Plxna4 that may be involved with host response and wound healing. We also found a group of basal-like cells labeled by ASPM that could be the progenitor cells of adult bladder urothelium. ASPM+ urothelial cells are significantly increased after injury by UPEC. In addition, specific transcription factors were found to be associated with urothelial cell differentiation. At the last, a number of interstitial cystitis/bladder pain syndrome-regulating genes were found differentially expressed among different urothelial cell subpopulations. Conclusions: Our study provides a comprehensive characterization of bladder urothelial cells, which is fundamental to understanding the biology of bladder urothelium and associated bladder disease.
Project description:The presence of carcinoma in situ (CIS) lesions in the urinary bladder is associated with a high risk of disease progression to a muscle invasive stage. In this study, we used microarray expression profiling to examine the gene expression patterns in superficial transitional cell carcinoma (sTCC) with surrounding CIS (13 patients), without surrounding CIS lesions (15 patients), and in muscle invasive carcinomas (mTCC; 13 patients). Hierarchical cluster analysis separated the sTCC samples according to the presence or absence of CIS in the surrounding urothelium. We identified a few gene clusters that contained genes with similar expression levels in transitional cell carcinoma (TCC) with surrounding CIS and invasive TCC. However, no close relationship between TCC with adjacent CIS and invasive TCC was observed using hierarchical cluster analysis. Expression profiling of a series of biopsies from normal urothelium and urothelium with CIS lesions from the same urinary bladder revealed that the gene expression found in sTCC with surrounding CIS is found also in CIS biopsies as well as in histologically normal samples adjacent to the CIS lesions. Furthermore, we also identified similar gene expression changes in mTCC samples. We used a supervised learning approach to build a 16-gene molecular CIS classifier. The classifier was able to classify sTCC samples according to the presence or absence of surrounding CIS with a high accuracy. This study demonstrates that a CIS gene expression signature is present not only in CIS biopsies but also in sTCC, mTCC, and, remarkably, in histologically normal urothelium from bladders with CIS. Identification of this expression signature could provide guidance for the selection of therapy and follow-up regimen in patients with early stage bladder cancer. Experiment Overall Design: See publication