Hedgehog signalling in Foxd1+ embryonic kidney stromal progenitors controls nephron formation via Cxcl12 and Wnt5a.

Congenital anomalies of the kidney and urinary tract (CAKUT) are characterised by a spectrum of structural and histologic abnormalities and are the major cause of childhood kidney failure. During kidney morphogenesis, the formation of a critical number of nephrons is an embryonic process supported, in part, by signalling between nephrogenic precursors and Foxd1-positive stromal progenitor cells. Low nephron number and abnormal patterning of the stroma are signature pathological features among CAKUT phenotypes with decreased kidney function. Despite their critical contribution to CAKUT pathogenesis, the mechanisms that underlie a low nephron number and the functional contribution of a disorganised renal stroma to nephron number are both poorly defined. Here, we identify a primary pathogenic role for increased Hedgehog signalling in embryonic renal stroma in the genesis of congenital low nephron number. Pharmacologic activation of Hedgehog (Hh) signalling in human kidney organoid tissue decreased the number of nephrons and generated excess stroma. The mechanisms underlying these pathogenic effects were delineated in genetic mouse models in which Hh signalling was constitutively activated in a cell lineage-specific manner. Cre-mediated excision of Ptch1 in Foxd1+ stromal progenitor cells, but not in Six2+ nephrogenic precursor cells, generated kidney malformation, identifying the stroma as a driver of low nephron number. Single-cell RNA sequencing analysis identified Cxcl12 and Wnt5a as downstream targets of increased stromal Hh signalling, findings supported by analysis in human kidney organoids. In vivo deficiency of Cxcl12 or Wnt5a in mice with increased stromal Hh signalling improved nephron endowment. These results demonstrate that dysregulated Hh signalling in embryonic renal stromal cells inhibits nephron formation in a manner dependent on Cxcl12 and Wnt5a. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Suppressor of fused controls cerebellum granule cell proliferation by suppressing Fgf8 and spatially regulating Gli proteins.

Cerebellar granule cell (GC) development relies on precise regulation of sonic hedgehog (Shh)-Gli signalling activity, failure of which is associated with motor disorders and medulloblastoma. Mutations in the pathway regulator suppressor of fused (Sufu), which modulates Gli activators and repressors, are linked to cerebellar dysfunction and tumourigenesis. The mechanism by which Sufu calibrates Shh signalling in GCs is unknown. Math1-Cre-mediated deletion of Sufu in mouse GC progenitors (GCPs) demonstrated that Sufu restricts GCP proliferation and promotes cell cycle exit, by promoting expression of Gli3R and suppressing Gli2 levels. Sufu is also required to promote a high threshold of pathway activity in GCPs. Remarkably, central cerebellar lobules are more deleteriously impacted by Sufu deletion, but are less sensitive to downstream genetic manipulations to reduce Gli2 expression or overexpress a Gli3R mimic, compared with anterior lobules. Transcriptome sequencing uncovered new Sufu targets, especially Fgf8, which is upregulated in Sufu-mutant GCPs. We demonstrate that Fgf8 is necessary and sufficient to drive Sufu-mutant GCP proliferation. This study reveals new insights into the spatial and temporal regulation of cerebellar Shh-Gli signalling, while uncovering new targets, such as Fgf8.

The levonorgestrel-releasing intrauterine system 52 mg as a contraceptive versus a therapeutic: essential differences and perspectives.

BACKGROUND: It is 100 years since the discovery of oestrogen and nearly that since the discovery of progesterone. It is over 50 years since the concept of using intrauterine progesterone. Ten years after its synthesis, the research using levonorgestrel as an intrauterine agent was introduced. AREAS COVERED: The pharmacodynamics and pharmacokinetics of LNG-IUSs and the LNG-IUS 52 mg in particular explain why intrauterine LNG is so highly effective for contraception. When intrauterine LNG is used therapeutically it should ideally be based on clinical monitoring of the pathology being treated rather than a fixed time period While the LNG-IUS 52 mg is probably required for most medical conditions, consideration should be given for using the LNG-IUS 13.5 mg for hyperplasia and endometrial protection during oestrogen therapy and for older women who appear more prone to a low rate of LNG induced breast cancer, although there is not yet an official indication for this. CONCLUSION: The desire for fertility control, therapy for various genital pathological conditions and reduction of repeated endometrial decidualization and inflammatory breakdown and its consequences, and menopausal problems can be aided by intrauterine LNG. This review explains how a contraceptive also became a WHO listed essential medicine.

There are significant differences at many levels in the use of intrauterine levonorgestrel for contraception when compared to using it as a therapeutic.

Pallister-Hall syndrome, GLI3, and kidney malformation.

Pallister-Hall syndrome (PHS) is a rare autosomal dominant disease diagnosed by the presence of hypothalamic hamartoma, mesoaxial polydactyly and a truncating variant in the middle third of the GLI-Kruppel family member 3 (GLI3) gene. PHS may also include a wide range of clinical phenotypes affecting multiple organ systems including congenital anomalies of the kidney and urinary tract (CAKUT). The observed clinical phenotypes are consistent with the essential role of GLI3, a transcriptional effector in the hedgehog (Hh) signaling pathway, in organogenesis. However, the mechanisms by which truncation of GLI3 in PHS results in such a variety of clinical phenotypes with variable severity, even within the same organ, remain unclear. In this study we focus on presentation of CAKUT in PHS. A systematic analysis of reported PHS patients (n = 78) revealed a prevalence of 26.9% (21/78) of CAKUT. Hypoplasia (± dysplasia) and agenesis were the two main types of CAKUT; bilateral and unilateral CAKUT were reported with equal frequency. Examination of clinical phenotypes with CAKUT revealed a significant association between CAKUT and craniofacial defects, bifid epiglottis and a Disorder of Sex Development, specifically affecting external genitalia. Lastly, we determined that PHS patients with CAKUT predominately had substitution type variants (as opposed to deletion type variants in non-CAKUT PHS patients) in the middle third of the GLI3 gene. These results provide a foundation for future work aimed at uncovering the molecular mechanisms by which variant GLI3 result in the wide range and severity of clinical features observed in PHS.

Hedgehog-GLI signaling in Foxd1-positive stromal cells promotes murine nephrogenesis via TGFß signaling.

Normal kidney function depends on the proper development of the nephron: the functional unit of the kidney. Reciprocal signaling interactions between the stroma and nephron progenitor compartment have been proposed to control nephron development. Here, we show that removal of hedgehog intracellular effector smoothened (Smo-deficient mutants) in the cortical stroma results in an abnormal renal capsule, and an expanded nephron progenitor domain with an accompanying decrease in nephron number via a block in epithelialization. We show that stromal-hedgehog-Smo signaling acts through a GLI3 repressor. Whole-kidney RNA sequencing and analysis of FACS-isolated stromal cells identified impaired TGFß2 signaling in Smo-deficient mutants. We show that neutralization and knockdown of TGFß2 in explants inhibited nephrogenesis. In addition, we demonstrate that concurrent deletion of Tgfbr2 in stromal and nephrogenic cells in vivo results in decreased nephron formation and an expanded nephrogenic precursor domain similar to that observed in Smo-deficient mutant mice. Together, our data suggest a mechanism whereby a stromal hedgehog-TGFß2 signaling axis acts to control nephrogenesis.

Oral and Dermal Bioavailability Studies of Polycyclic Aromatic Hydrocarbons from Soils Containing Weathered Fragments of Clay Shooting Targets.

The relative oral bioavailability and dermal absorption of chemical substances from environmental media are key factors that are needed to accurately estimate site-specific risks and manage human exposures. This study evaluated the in vivo relative oral bioavailability and in vitro dermal absorption of several polycyclic aromatic hydrocarbons (PAHs) found in soils collected from two formerly used Department of Defense sites impacted by weathered fragments of clay shooting targets. Concentrations of individual carcinogenic PAHs in the ≤250 µm fraction of soil ranged from approximately 0.1 to 100 mg/kg. A novel sample preparation method was developed to produce accurate and precise test diets for oral studies. The resulting test diets showed consistent concentrations of PAHs in soil- and soil-extract-amended diets and a consistent PAH concentration profile. Mean oral relative bioavailability factors (RBAFs) and dermal absorption fractions (ABSd) for benzo(a)pyrene ranged from 8 to 14% and 0.58 to 1.3%, respectively. Using the RBAF and ABSd values, measured here, for benzo(a)pyrene in USEPA's regional screening level equations yields concentrations for residential soils that are approximately eight times higher than those when default values are used (e.g., 9.6 vs 1.2 mg/kg at a target excess risk of 1 × 10-5).

Transforming growth factor beta signaling functions during mammalian kidney development.

Aberrant transforming growth factor beta (TGFß) signaling during embryogenesis is implicated in severe congenital abnormalities, including kidney malformations. However, the molecular mechanisms that underlie congenital kidney malformations related to TGFß signaling remain poorly understood. Here, we review current understanding of the lineage-specific roles of TGFß signaling during kidney development and how dysregulation of TGFß signaling contributes to the pathogenesis of kidney malformation.

Testing the validity of a proposed dermal cancer slope factor for Benzo[a]pyrene.

In 2014, the United States Environmental Protection Agency (EPA) proposed a Dermal Slope Factor (DSF) for benzo[a]pyrene (BaP) of 0.006 (µg/day)-1 (USEPA 2014a). It would make cancer risk estimates associated with soil contact 100 times greater than those from soil ingestion and would predict that a large fraction of skin Basal Cell Carcinomas (BCCs) and Squamous Cell Carcinomas (SCCs) worldwide are caused by low level dermal exposures to PAHs, such as BaP. This is not logical given that sunlight (ultraviolet radiation (UV)) exposure is the generally recognized cause of BCCs and SCCs. This paper critically evaluates the proposed DSF. First, a reality check is performed using EPA standard risk assessment methods and comparing the results to actual BCC and SCC rates in the U.S. population. Then, the biological plausibility of the mechanism by which PAHs might cause human skin cancer is evaluated by exploring the generally recognized etiology of human skin cancer and comparing the genetic mutation signatures of rodent skin tumors caused by PAH exposures to those of human skin cancers. It is concluded that scientific flaws resulted in a proposed DSF value that greatly overestimates the skin cancer risk for humans dermally exposed to BaP in soil.

Advanced endoscopic gastrointestinal techniques for the bariatric patient: implications for the anesthesia provider.

PURPOSE OF REVIEW: The incidence of obesity and the use of endoscopy have risen concurrently throughout the 21st century. Bariatric patients may present to the endoscopy suite for primary treatments as well as preoperatively and postoperatively from bariatric surgery. However, over the past 10 years, endoscopic bariatric and metabolic therapies (EBMTs) have emerged as viable alternatives to more invasive surgical approaches for weight loss. RECENT FINDINGS: The United States Food and Drug Administration (FDA) has approved several different gastric EBMTs including aspiration therapy, intragastric balloons, and endoscopic suturing. Other small intestine EBMTs including duodenal mucosal resurfacing, endoluminal magnetic partial jejunal diversion, and Duodenal-Jejunal Bypass Liner are not yet FDA approved, but are actively being investigated. SUMMARY: Obesity causes anatomic and physiologic changes to every aspect of the human body. All EBMTs have specific nuances with important implications for the anesthesiologist. By considering both patient and procedural factors, the anesthesiologist will be able to perform a safe and effective anesthetic.

Climate warming restructures an aquatic food web over 28 years.

Climate warming can restructure lake food webs if trophic levels differ in their thermal responses, but evidence for these changes and their underlying mechanisms remain scarce in nature. Here we document how warming lake temperatures by up to 2°C, rather than changes in trophic state or fishing effort, have restructured the pelagic food web of a large European lake (Lake Maggiore, Italy). Our approach exploited abundance and biomass data collected weekly to yearly across five trophic levels from 1981 to 2008. Temperature generally had stronger effects on taxa than changes in fish predation or trophic state mediated through primary productivity. Consequently, we found that, as the lake warmed, the food web shifted in numerical abundance towards predators occupying middle trophic positions. Of these taxa, the spiny water flea (Bythotrephes longimanus) most prospered. Bythotrephes strongly limited abundances of the keystone grazer Daphnia, strengthening top-down structuring of the food web. Warmer temperatures partly restructured the food web by advancing peak Bythotrephes densities by approximately 60 days and extending periods of positive population growth by three times. Nonetheless, our results suggested that advances in the timing and size of peak Bythotrephes densities could not outpace changes in the timing and size of peak densities in their Daphnia prey. Our results provide rare evidence from nature as to how long-term warming can favour higher trophic levels, with the potential to strengthen top-down control of food webs.

Generation of infant- and pediatric-derived urinary induced pluripotent stem cells competent to form kidney organoids.

BACKGROUND: Human induced pluripotent stem cells (iPSCs) are a promising tool to investigate pathogenic mechanisms underlying human genetic conditions, such as congenital anomalies of the kidney and urinary tract (CAKUT). Currently, iPSC-based research in pediatrics is limited by the invasiveness of cell collection. METHODS: Urine cells (UCs) were isolated from pediatric urine specimens, including bag collections, and reprogrammed using episomal vectors into urinary iPSCs (UiPSCs). Following iPSC-quality assessment, human kidney organoids were generated. RESULTS: UCs were isolated from 71% (12/17) of single, remnant urine samples obtained in an outpatient setting (patients 1 month-17 years, volumes 10-75 ml). Three independent UCs were reprogrammed to UiPSCs with early episome loss, confirmed pluripotency and normal karyotyping. Subsequently, these UiPSCs were successfully differentiated into kidney organoids, closely resembling organoids generated from control fibroblast-derived iPSCs. Importantly, under research conditions with immediate sample processing, UC isolation was successful 100% for target pediatric CAKUT patients and controls (11/11) after at most two urine collections. CONCLUSIONS: Urine in small volumes or collected in bags is a reliable source for reprogrammable somatic cells that can be utilized to generate kidney organoids. This constitutes an attractive approach for patient-specific iPSC research involving infants and children with wide applicability and a low threshold for participation.

Road Salt Impacts Freshwater Zooplankton at Concentrations below Current Water Quality Guidelines.

Widespread use of NaCl for road deicing has caused increased chloride concentrations in lakes near urban centers and areas of high road density. Chloride can be toxic, and water quality guidelines have been created to regulate it and protect aquatic life. However, these guidelines may not adequately protect organisms in low-nutrient, soft water lakes such as those underlain by the Precambrian Shield. We tested this hypothesis by conducting laboratory experiments on six Daphnia species using a soft water culture medium. We also examined temporal changes in cladoceran assemblages in the sediments of two small lakes on the Canadian Shield: one near a highway and the other >3 km from roads where salt is applied in the winter. Our results showed that Daphnia were sensitive to low chloride concentrations with decreased reproduction and increased mortality occurring between 5 and 40 mg Cl-/L. Analysis of cladoceran remains in lake sediments revealed changes in assemblage composition that coincided with the initial application of road salt in this region. In contrast, there were no changes detected in the remote lake. We found that 22.7% of recreational lakes in Ontario have chloride concentrations between 5 and 40 mg/L suggesting that cladoceran zooplankton in these lakes may already be experiencing negative effects of chloride.

Lineage-specific roles of hedgehog-GLI signaling during mammalian kidney development.

Aberrant hedgehog (Hh) signaling during embryogenesis results in various severe congenital abnormalities, including renal malformations. The molecular mechanisms that underlie congenital renal malformations remain poorly understood. Here, we review the current understanding of the lineage-specific roles of Hh signaling during renal morphogenesis and how aberrant Hh signaling during embryonic kidney development contributes to renal malformation.

Allodynography: Reliability of a New Procedure for Objective Clinical Examination of Static Mechanical Allodynia.

OBJECTIVE: There is a need for reliable and valid clinical assessment tools for quantifying allodynia in neuropathic pain. Allodynography has been proposed as a useful standardized procedure for clinical assessment of mechanical allodynia. This study (www.clinicaltrials.gov NCT02070367) undertook preliminary investigation of the measurement properties of allodynography, a new standardized clinical examination procedure for mapping the area of cutaneous allodynia. METHODS: Persons with pain in one upper extremity after complex regional pain syndrome, a peripheral nerve injury, or who had recently experienced a hand fracture were recruited for assessment of static mechanical allodynia (based on perception of a 15g force stimulus delivered by Semmes-Weinstein monofilament #5.18 as painful) by two raters at baseline; the assessment was repeated one week later. RESULTS: Single-measures estimates suggested inter-rater reliability for allodynography was excellent at an intraclass correlation coefficient (ICC) of 0.97 (N = 12); test-retest reliability was also excellent at ICC = 0.89 (N = 10) for allodynography (P < 0.001 for both). Confidence intervals' lower bounds confirm inter-rater reliability as excellent (0.90) but were less definitive for test-retest (0.59). CONCLUSIONS: This preliminary study supports the inter-rater and test-retest reliability of allodynography. Studies on larger samples in multiple contexts and reporting other measurement properties are warranted.

Risk assessment implications of site-specific oral relative bioavailability factors and dermal absorption fractions for polycyclic aromatic hydrocarbons in surface soils impacted by clay skeet target fragments.

Risk assessment conclusions for a site may differ when using site-specific versus default values for the relative bioavailability factor (RBAF) and dermal absorption fraction (ABS.d), because these inputs affect both surface soil screening levels and risk/hazard estimates. Indeed, our case study demonstrates that different conclusions may be reached as to regulatory need for remedial action to protect human health when evaluating soil sampling data for seven carcinogenic polycyclic aromatic hydrocarbons (PAHs) using site-specific versus default TCEQ and USEPA residential soil screening levels. Use of site-specific RBAF and ABS.d values increased carcinogenicity-based TCEQ and USEPA surface soil screening levels for PAHs by 4.4- and 6-fold on average, respectively. Soil screening levels for PAHs were more sensitive to changes in ingestion exposure route parameters than to changes in dermal exposure route parameters. Accordingly, site-specific RBAF and ABS.d information has important implications for screening chemicals at PAH-impacted sites, and in addition provides more realistic estimates of risks/hazards posed by PAHs in soil with reduced uncertainty compared to estimates based on default RBAF and ABS.d values. Although default values are generally deemed acceptable by regulatory agencies, use of risk/hazard estimates based on these default values may compel insufficiently justified remedial action in some instances.

Airway Management and Clinical Outcomes in External Laryngeal Trauma: A Case Series.

External laryngeal trauma is a rare but potentially fatal event that presents several management challenges. This retrospective observational case series conducted at a level-1 trauma center over a 12-year period consists of 62 cases of acute external laryngeal trauma. Patient demographics, mode and mechanisms of injury, presenting signs and symptoms, initial imaging results, airway management, time to surgical management, and 6-month outcomes including airway status, deglutition status, and voice quality were investigated. No difference was found in mortality or 6-month outcomes between patients requiring surgical repair and/or tracheostomy versus patients with less severe injuries managed conservatively.

Protein Kinase 2ß Is Expressed in Neural Crest-Derived Urinary Pacemaker Cells and Required for Pyeloureteric Contraction.

Nonobstructive hydronephrosis, defined as dilatation of the renal pelvis with or without dilatation of the ureter, is the most common antenatal abnormality detected by fetal ultrasound. Yet, the etiology of nonobstructive hydronephrosis is poorly defined. We previously demonstrated that defective development of urinary tract pacemaker cells (utPMCs) expressing hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3) and the stem cell marker cKIT causes abnormal ureteric peristalsis and nonobstructive hydronephrosis. However, further investigation of utPMC development and function is limited by lack of knowledge regarding the embryonic derivation, development, and molecular apparatus of these cells. Here, we used lineage tracing in mice to identify cells that give rise to utPMCs. Neural crest cells (NCCs) indelibly labeled with tdTomato expressed HCN3 and cKIT. Furthermore, purified HCN3+ and cKIT+ utPMCs were enriched in Sox10 and Tfap-2α, markers of NCCs. Sequencing of purified RNA from HCN3+ cells revealed enrichment of a small subset of RNAs, including RNA encoding protein kinase 2ß (PTK2ß), a Ca2+-dependent tyrosine kinase that regulates ion channel activity in neurons. Immunofluorescence analysis in situ revealed PTK2ß expression in NCCs as early as embryonic day 12.5 and in HCN3+ and cKIT+ utPMCs as early as embryonic day 15.5, with sustained expression in HCN3+ utPMCs until postnatal week 8. Pharmacologic inhibition of PTK2ß in murine pyeloureteral tissue explants inhibited contraction frequency. Together, these results demonstrate that utPMCs are derived from NCCs, identify new markers of utPMCs, and demonstrate a functional contribution of PTK2ß to utPMC function.

Activated Hedgehog-GLI Signaling Causes Congenital Ureteropelvic Junction Obstruction.

Intrinsic ureteropelvic junction obstruction is the most common cause of congenital hydronephrosis, yet the underlying pathogenesis is undefined. Hedgehog proteins control morphogenesis by promoting GLI-dependent transcriptional activation and inhibiting the formation of the GLI3 transcriptional repressor. Hedgehog regulates differentiation and proliferation of ureteric smooth muscle progenitor cells during murine kidney-ureter development. Histopathologic findings of smooth muscle cell hypertrophy and stroma-like cells, consistently observed in obstructing tissue at the time of surgical correction, suggest that Hedgehog signaling is abnormally regulated during the genesis of congenital intrinsic ureteropelvic junction obstruction. Here, we demonstrate that constitutively active Hedgehog signaling in murine intermediate mesoderm-derived renal progenitors results in hydronephrosis and failure to develop a patent pelvic-ureteric junction. Tissue obstructing the ureteropelvic junction was marked as early as E13.5 by an ectopic population of cells expressing Ptch2, a Hedgehog signaling target. Constitutive expression of GLI3 repressor in Ptch1-deficient mice rescued ectopic Ptch2 expression and obstructive hydronephrosis. Whole transcriptome analysis of isolated Ptch2+ cells revealed coexpression of genes characteristic of stromal progenitor cells. Genetic lineage tracing indicated that stromal cells blocking the ureteropelvic junction were derived from intermediate mesoderm-derived renal progenitors and were distinct from the smooth muscle or epithelial lineages. Analysis of obstructive ureteric tissue resected from children with congenital intrinsic ureteropelvic junction obstruction revealed a molecular signature similar to that observed in Ptch1-deficient mice. Together, these results demonstrate a Hedgehog-dependent mechanism underlying mammalian intrinsic ureteropelvic junction obstruction.

Suppressor of fused controls cerebellar neuronal differentiation in a manner modulated by GLI3 repressor and Fgf15.

BACKGROUND: Deficiency of Suppressor of Fused (SuFu), an intracellular mediator of Hedgehog signaling, in the murine mid-hindbrain disrupts cerebellar morphogenesis and cell differentiation in a manner that is rescued by constitutive expression of GLI3 transcriptional repressor (GLI3R). Here, we determined SuFu functions in cerebellar radial precursors following the stage of mid-hindbrain specification using a Blbp-Cre transgene. RESULTS: SuFu-deficient cerebella were severely dysplastic, and characterized by laminar disorganization, and delayed differentiation of ventricular zone-derived precursors. In vitro analysis of cerebellar precursors isolated from control and mutant mice demonstrated an increased proportion of radial glial precursors vs. Tuj1-positive neurons in mutant cultures. Abnormal cell differentiation in SuFu-deficient precursors was rescued by a constitutively expressed GLI3R knock-in allele, albeit with variable penetrance. Using RNA expression analysis in control and SuFu-deficient cerebellar anlage, we identified up-regulation of Fgf15 in mutant tissue. Strikingly, exogenous hFGF19, a mFGF15 ortholog, inhibited neuronal differentiation in cultures of wild-type cerebellar precursors. Moreover, siRNA-mediated knockdown of Fgf15 in SuFu-deficient cerebellar precursors rescued their delayed differentiation to neurons. CONCLUSIONS: Together, our results show that SuFu promotes cerebellar radial precursor differentiation to neurons. SuFu function is mediated in part by GLI3R and down-regulation of Fgf15 expression. Developmental Dynamics 247:156-169, 2018. © 2017 Wiley Periodicals, Inc.

Urogenital development in Pallister-Hall syndrome is disrupted in a cell-lineage-specific manner by constitutive expression of GLI3 repressor.

Pallister-Hall syndrome (PHS) is a rare disorder caused by mutations in GLI3 that produce a transcriptional repressor (GLI3R). Individuals with PHS present with a variably penetrant variety of urogenital system malformations, including renal aplasia or hypoplasia, hydroureter, hydronephrosis or a common urogenital sinus. The embryologic mechanisms controlled by GLI3R that result in these pathologic phenotypes are undefined. We demonstrate that germline expression of GLI3R causes renal hypoplasia, associated with decreased nephron number, and hydroureter and hydronephrosis, caused by blind-ending ureters. Mice with obligate GLI3R expression also displayed duplication of the ureters that was caused by aberrant common nephric duct patterning and ureteric stalk outgrowth. These developmental abnormalities are associated with suppressed Hedgehog signaling activity in the cloaca and adjacent vesicular mesenchyme. Mice with conditional expression of GLI3R were utilized to identify lineage-specific effects of GLI3R. In the ureteric bud, GLI3R expression decreased branching morphogenesis. In Six2-positive nephrogenic progenitors, GLI3R decreased progenitor cell proliferation reducing the number of nephrogenic precursor structures. Using mutant mice with Gli3R and Gli3 null alleles, we demonstrate that urogenital system patterning and development is controlled by the levels of GLI3R and not by an absence of full-length GLI3. We conclude that the urogenital system phenotypes observed in PHS are caused by GLI3R-dependent perturbations in nephric duct patterning, renal branching morphogenesis and nephrogenic progenitor self-renewal.