The origin of renal fibroblasts/myofibroblasts and the signals that trigger fibrosis.

Renal fibrosis is a common characteristic of chronic kidney disease (CKD). Aberrant and excessive depositions of extracellular matrix (ECM) proteins in both glomeruli and interstitial regions are typical hallmarks of renal fibrosis and amplify the severity of kidney injury. To date, an approved therapy specifically targeted to renal fibrosis is needed to mitigate or even retard renal fibrosis.

Validation of a Three-Dimensional Method for Counting and Sizing Podocytes in Whole Glomeruli.

Podocyte depletion is sufficient for the development of numerous glomerular diseases and can be absolute (loss of podocytes) or relative (reduced number of podocytes per volume of glomerulus). Commonly used methods to quantify podocyte depletion introduce bias, whereas gold standard stereologic methodologies are time consuming and impractical. We developed a novel approach for assessing podocyte depletion in whole glomeruli that combines immunofluorescence, optical clearing, confocal microscopy, and three-dimensional analysis.

A protocol for the identification and validation of novel genetic causes of kidney disease.

Background: Genetic renal diseases (GRD) are a heterogeneous and incompletely understood group of disorders accounting for approximately 10 % of those diagnosed with kidney disease. The advent of Next Generation sequencing and new approaches to disease modelling may allow the identification and validation of novel genetic variants in patients with previously incompletely explained or understood GRD.

Methods/design: This study will recruit participants in families/trios from a multidisciplinary sub-specialty Renal Genetics Clinic where known genetic causes of GRD have been excluded or where genetic testing is not available.

The Smad3/Smad4/CDK9 complex promotes renal fibrosis in mice with unilateral ureteral obstruction.

Transforming growth factor-β1 (TGF-β1)/Smad signaling has a central role in the pathogenesis of renal fibrosis. Smad3 and Smad4 are pro-fibrotic, while Smad2 is anti-fibrotic. However, these Smads form heterogeneous complexes, the functions of which are poorly understood.

Smad3 deficiency protects mice from obesity-induced podocyte injury that precedes insulin resistance.

Signaling by TGF-β/Smad3 plays a key role in renal fibrosis. As obesity is one of the major risk factors of chronic and end-stage renal disease, we studied the role of Smad3 signaling in the pathogenesis of obesity-related renal disease. After switching to a high fat diet, the onset of Smad3 C-terminal phosphorylation, increase in albuminuria, and the early stages of peripheral and renal insulin resistance occurred at 1 day, and 4 and 8 weeks, respectively, in C57BL/6 mice.

Congenital anomalies of the kidney and urinary tract genetics in mice and men.

The most common cause of paediatric end-stage kidney disease results from congenital anomalies of the kidney and urinary tract (CAKUT). Genetic manipulation in mice has provided insight into the developmental events that give rise to the broad spectrum of malformations associated with CAKUT. Despite the increase in the number of identified CAKUT-causing genes, the underlying genetic cause for the majority of patients with CAKUT remains unknown.

A mouse splice-site mutant and individuals with atypical chromosome 22q11.2 deletions demonstrate the crucial role for crkl in craniofacial and pharyngeal development.

The 22q11.2 deletion syndrome (22q11DS) is thought to be a contiguous gene syndrome caused by haploinsufficiency for a variable number of genes with overlapping function during the development of the craniofacial, pharyngeal and cardiac structures. The complexity of genetic and developmental anomalies resulting in 22q11DS has made attributing causation to specific genes difficult.

Copy-number variation associated with congenital anomalies of the kidney and urinary tract.

Background: The most common cause of end-stage renal disease in children can be attributed to congenital anomalies of the kidney and urinary tract (CAKUT). Despite this high incidence of disease, the genetic mutations responsible for the majority of CAKUT cases remain unknown.

Methods: To identify novel genomic regions associated with CAKUT, we screened 178 children presenting with the entire spectrum of structural anomalies associated with CAKUT for submicroscopic chromosomal imbalances (deletions or duplications) using single-nucleotide polymorphism (SNP) microarrays.

Regulation of renal fibrosis by Smad3 Thr388 phosphorylation.

Transforming growth factor-β (TGF-β) promotes tissue fibrosis via receptor-mediated phosphorylation of the receptor-activated Smad2/3, together with Smad4. Of these, Smad3 plays a major profibrotic role in mouse models of tissue fibrosis. Transcriptional activity of the Smad3 protein is regulated by phosphorylation of residues in the C-terminal domain and the linker region.

bfb, a novel ENU-induced blebs mutant resulting from a missense mutation in Fras1.

Fras1 is an extracellular matrix associated protein with essential roles in adhesion of epithelia and mesenchyme during early embryonic development. The adhesive function of Fras1 is achieved through interaction with a group of related proteins, Frem 1-3, and a cytoplasmic adaptor protein Grip1. Mutation of each of these proteins results in characteristic epithelial blistering and have therefore become known as "blebs" proteins.

Cauli: a mouse strain with an Ift140 mutation that results in a skeletal ciliopathy modelling Jeune syndrome.

Cilia are architecturally complex organelles that protrude from the cell membrane and have signalling, sensory and motility functions that are central to normal tissue development and homeostasis. There are two broad categories of cilia; motile and non-motile, or primary, cilia. The central role of primary cilia in health and disease has become prominent in the past decade with the recognition of a number of human syndromes that result from defects in the formation or function of primary cilia.

Resolvin D1 protects podocytes in adriamycin-induced nephropathy through modulation of 14-3-3β acetylation.

Resolvin D1 (RvD1) is a lipid-derived mediator generated during the resolution inflammation. While the immunoresolvent effects of Resolvins have been extensively studied in leukocytes, actions of Resolvins on intrinsic kidney cells have received little attention. The podocyte plays a central role in glomerular function, and podocyte damage can lead to proteinuria and glomerulosclerosis.

Genome-wide ENU mutagenesis in combination with high density SNP analysis and exome sequencing provides rapid identification of novel mouse models of developmental disease.

Background: Mice harbouring gene mutations that cause phenotypic abnormalities during organogenesis are invaluable tools for linking gene function to normal development and human disorders. To generate mouse models harbouring novel alleles that are involved in organogenesis we conducted a phenotype-driven, genome-wide mutagenesis screen in mice using the mutagen N-ethyl-N-nitrosourea (ENU).

Methodology/principal Findings: ENU was injected into male C57BL/6 mice and the mutations transmitted through the germ-line.

Glomerular endothelial cell injury and damage precedes that of podocytes in adriamycin-induced nephropathy.

The role of podocytes in the development and progression of glomerular disease has been extensively investigated in the past decade. However, the importance of glomerular endothelial cells in the pathogenesis of proteinuria and glomerulosclerosis has been largely ignored. Recent studies have demonstrated that endothelial nitric oxide synthatase (eNOS) deficiency exacerbates renal injury in anti-GBM and remnant kidney models and accelerates diabetic kidney damage.

High nephron endowment protects against salt-induced hypertension.

While low nephron number is associated with increased risk of developing cardiovascular and renal disease, the functional consequences of a high nephron number are unknown. We tested the hypothesis that a high nephron number provides protection against hypertensive and renal insults. Mean arterial pressure (MAP) and renal function were characterized in male wild-type (WT) and transforming growth factor-β2 heterozygous (Tgfb2(+/-)) mice under basal conditions and following a chronic high-salt diet.

Expression patterns and roles of periostin during kidney and ureter development.

Purpose: Periostin is a secreted extracellular matrix protein that is differentially expressed in the developing kidney. We analyzed the temporal-spatial expression of periostin in the developing kidney and ureter as well as its roles in ureter branching morphogenesis, nephrogenesis and ureter development.

Materials And Methods: RNA in situ hybridization and immunofluorescence histochemistry were used to investigate the expression of periostin, αv integrin and α-smooth muscle actin during mouse renal and ureteral development.

Betaglycan is required for the establishment of nephron endowment in the mouse.

Betaglycan is an accessory receptor for the transforming growth factor-β (TGFβ) superfamily, many members of which play key roles in kidney development. The purpose of this study was to define the role of this co-receptor on fetal murine kidney development. Stereological examination of embryonic and adult betaglycan heterozygous kidneys revealed augmented nephron number relative to littermate controls.

Blockade of endothelial-mesenchymal transition by a Smad3 inhibitor delays the early development of streptozotocin-induced diabetic nephropathy.

Objective: A multicenter, controlled trial showed that early blockade of the renin-angiotensin system in patients with type 1 diabetes and normoalbuminuria did not retard the progression of nephropathy, suggesting that other mechanism(s) are involved in the pathogenesis of early diabetic nephropathy (diabetic nephropathy). We have previously demonstrated that endothelial-mesenchymal-transition (EndoMT) contributes to the early development of renal interstitial fibrosis independently of microalbuminuria in mice with streptozotocin (STZ)-induced diabetes. In the present study, we hypothesized that blocking EndoMT reduces the early development of diabetic nephropathy.

Redirection of renal mesenchyme to stromal and chondrocytic fates in the presence of TGF-beta2.

Many members of the transforming growth factor-beta (TGF-beta) superfamily have been shown to be important regulators of metanephric development. In this study, we characterized the effect of TGF-beta2 on metanephric development. Rat and mouse metanephroi cultured in the presence of exogenous TGF-beta2 for up to 15 days were small, and contained rudimentary ureteric branches and few glomeruli.

Sexual dimorphism in mouse metanephroi exposed to 17 beta-estradiol in vitro.

Unlabelled: 17beta-Estradiol, the most potent circulating estrogen, has been shown to greatly impact on the development and formation of tissues of the urogenital tract. The adult kidney has previously been shown to be highly responsive to 17beta-estradiol stimulation. However, the direct effect of 17beta-estradiol on kidney development remains unclear.

Augmented and accelerated nephrogenesis in TGF-beta2 heterozygous mutant mice.

Several members of the transforming growth factor-beta (TGF-beta) superfamily play key roles in kidney development, either directly or indirectly regulating nephron number. Although low nephron number is a risk factor for cardiovascular and renal disease, the implications of increased nephron number has not been examined due to the absence of appropriate animal models. Here, using unbiased stereology we demonstrated that kidneys from TGF-beta2 heterozygous (TGF-beta2(+/-)) mice have approximately 60% more nephrons than wild-type mice at postnatal day 30.

Spatial gene expression in the T-stage mouse metanephros.

The E11.5 mouse metanephros is comprised of a T-stage ureteric epithelial tubule sub-divided into tip and trunk cells surrounded by metanephric mesenchyme (MM). Tip cells are induced to undergo branching morphogenesis by the MM.

Imaging the embryonic kidney.

The structural and functional development of the permanent mammalian kidney or metanephros is a complex process involving the actions of thousands of gene products, complex cell movements and tissue patterning in three dimensions (3D). This review focuses on the recent advances made in imaging technology, processing and analysis combined with mouse genetics and the generation of protein-reporter mice which has enabled us to monitor the development and movement of defined cell populations within the developing kidney in 3D and over time (4D).

Oncogenic function for the Dlg1 mammalian homolog of the Drosophila discs-large tumor suppressor.

The fact that several different human virus oncoproteins, including adenovirus type 9 E4-ORF1, evolved to target the Dlg1 mammalian homolog of the membrane-associated Drosophila discs-large tumor suppressor has implicated this cellular factor in human cancer. Despite a general belief that such interactions function solely to inactivate this suspected human tumor suppressor protein, we demonstrate here that E4-ORF1 specifically requires endogenous Dlg1 to provoke oncogenic activation of phosphatidylinositol 3-kinase (PI3K) in cells. Based on our results, we propose a model wherein E4-ORF1 binding to Dlg1 triggers the resulting complex to translocate to the plasma membrane and, at this site, to promote Ras-mediated PI3K activation.

Differential gene expression in the developing mouse ureter.

In many instances, kidney dysgenesis results as a secondary consequence to defects in the development of the ureter. Through the use of mouse genetics a number of genes associated with such malformations have been identified, however, the cause of many other abnormalities remain unknown. In order to identify novel genes involved in ureter development we compared gene expression in embryonic day (E) 12.