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Chronic kidney disease is a leading cause of death in the United States. Tubulointerstitial fibrosis (TIF) is considered the final common pathway leading to end-stage renal disease (ESRD). Here, we used pharmacologic, genetic, in vivo, and in vitro experiments to show that activation of the Notch pathway in tubular epithelial cells (TECs) in patients and in mouse models of TIF plays a role in TIF development. Expression of Notch in renal TECs was found to be both necessary and sufficient for TIF development. Genetic deletion of the Notch pathway in TECs reduced renal fibrosis. Consistent with this, TEC-specific expression of active Notch 1 caused rapid development of TIF. Pharmacologic inhibition of Notch activation using a γ-secretase inhibitor ameliorated TIF. In summary, our experiments establish that epithelial injury and Notch signaling play key roles in fibrosis development and indicate that Notch blockade may be a therapeutic strategy to reduce fibrosis and ESRD development., Introduction In the United States, 20 million people have chronic kidney disease (CKD), the ninth leading cause of death in the country (1). Tubulointerstitial fibrosis (TIF) is uniformly observed and [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ydbio.2007.09.054 Byline: Barbara Probst (a), Rebecca Rock (b), Manfred Gessler (b), Andrea Vortkamp (c), Andreas W. Puschel (a) Keywords: Four-jointed; Dendrite; Hippocampus; Planar cell polarity Abstract: The extrinsic and intrinsic factors that regulate the size and complexity of dendritic arborizations are still poorly understood. Here we identify Fjx1, the rodent ortholog of the Drososphila planar cell polarity (PCP) protein Four-jointed (Fj), as a new inhibitory factor that regulates dendrite extension. The Drosophila gene four-jointed (fj) has been suggested to provide directional information in wing discs, but the mechanism how it acts is only poorly understood and the function of its mammalian homolog Fjx1 remains to be investigated. We analyzed the phenotype of a null mutation for mouse Fjx1. Homozygous Fjx1 mutants show an abnormal morphology of dendritic arbors in the hippocampus. In cultured hippocampal neurons from Fjx1 mutant mice, loss of Fjx1 resulted in an increase in dendrite extension and branching. Addition of Fjx1 to cultures of dissociated hippocampal neurons had the opposite effect and reduced the length of dendrites and decreased dendritic branching. Rescue experiments with cultured neurons showed that Fjx1 can act both cell-autonomously and non-autonomously. Our results identify Fjx1 as a new inhibitory factor that regulates dendrite extension. Author Affiliation: (a) Abteilung Molekularbiologie, Institut fur Allgemeine Zoologie und Genetik, Westfalische Wilhelms-Universitat Munster, SchloAplatz 5, D-48149 Munster, Germany (b) Theodor-Boveri-Institut (Biozentrum), Physiologische Chemie I, Julius-Maximilians-Universitat Wurzburg, Am Hubland, D-97074 Wurzburg, Germany (c) Zentrum fur Medizinische Biotechnologie, Abteilung Entwicklungsbiologie, Universitat Duisburg-Essen, Universitatsstr. D-45117 Essen, Germany Article History: Received 15 August 2007; Revised 24 September 2007; Accepted 25 September 2007

Wilms tumor (WT) is the most common renal tumor in childhood. We and others have previously identified oncogenic driver mutations affecting the microprocessor genes DROSHA and DGCR8 that lead to altered miRNA expression patterns. In the case of DGCR8 , a single recurrent hotspot mutation (E518K) was found in the RNA binding domain. To functionally assess this mutation in vitro , we generated mouse Dgcr8 -KO embryonic stem cell (mESC) lines with an inducible expression of wild-type or mutant DGCR8 , mirroring the hemizygous mutant expression seen in WT. RNA-seq analysis revealed significant differences of miRNA expression profiles in DGCR8-E518K compared with DGCR8-wild-type mESCs. The E518K mutation only led to a partial rescue of the reported miRNA processing defect in Dgcr8 -KO, with selectively reduced expression of numerous canonical miRNAs. Nevertheless, DGCR8-E518K retained significant activity given its ability to still process many miRNAs. Subsequent to altered miRNA levels, the expression of mRNA targets was likewise changed. Functional assays showed that DGCR8-E518K cells still have a partial proliferation and differentiation defect but were able to rescue critical biological processes in embryoid body development. The stem cell program could be shut down and all three germ layers were formed. These findings suggest that the E518K mutation leads to a partial reduction of microprocessor activity and altered specificity with selective impairment only in certain developmental contexts, apparently including nephrogenesis. [ABSTRACT FROM AUTHOR]

Kidney development has often served as a model for epithelial-mesenchymal cell interaction where the branching epithelium of the ureteric bud induces the metanephrogenic mesenchyme to form epithelial nephrons. In a screen for genes differentially expressed during kidney development, we have identified a novel gene that is dynamically expressed in the branching ureter and the developing nephrons. It was designated Emu1 since it shares an N-terminal cysteine-rich domain with Emilin1/2 and Multimerin. This highly conserved EMI domain is also found in another novel protein (Emu2) of similar protein structure: an N-terminal signal peptide followed by the EMI domain, an interrupted collagen stretch, and a conserved C-terminal domain of unknown function. We identified two further secreted EMI domain proteins, prompting us to compare their gene and protein structures, the EMI domain phylogeny, as well as the embryonic expression pattern of known (Emilin1/2, Multimerin) and novel (Emu1/2, Emilin3, Multimerin2) Emu gene family members. Emu1 and Emu2 not only show a similar structural organization, but furthermore a striking complementary expression in organs developing through epithelial-mesenchymal interactions. In these tissues, Emu1 is restricted to epithelial and Emu2 to mesenchymal cells. Preliminary biochemical analysis of Emu1/2 confirmed that they are secreted glycoproteins which are attached to the extracellular matrix and capable of forming homo- and heteromers via disulfide bonding. The widespread, but individually distinct expression patterns of all Emu gene family members suggest multiple functions during mouse embryogenesis. Their multidomain protein structure may indicate that Emu proteins interact with several different extracellular matrix components and serve to connect and integrate the function of multiple partner molecules. Key Words: Emilin; Multimerin; kidney; Emu1; Emu2; EMI domain; EndoGlyx-1; epithelial-mesenchymal interactions; extracellular matrix; glycosylation; disulfide bonds; cysteine-rich; collagen.

Research has been conducted on the T-box proteins. The role of these proteins in cardiac development and the consequences of the TBX5 mutations have been investigated via the engineered mice containing a deletion in Tbx5 alleles and the results are discussed.

In children, renal cell carcinoma (RCC) is rare. This study is the first report of pediatric patients with RCC registered by the International Society of Pediatric Oncology‐Renal Tumor Study Group (SIOP‐RTSG). Pediatric patients with histologically confirmed RCC, registered in SIOP 93‐01, 2001 and UK‐IMPORT databases, were included. Event‐free survival (EFS) and overall survival (OS) were analyzed using the Kaplan‐Meier method. Between 1993 and 2019, 122 pediatric patients with RCC were registered. Available detailed data (n = 111) revealed 56 localized, 30 regionally advanced, 25 metastatic and no bilateral cases. Histological classification according to World Health Organization 2004, including immunohistochemical and molecular testing for transcription factor E3 (TFE3) and/or EB (TFEB) translocation, was available for 65/122 patients. In this group, the most common histological subtypes were translocation type RCC (MiT‐RCC) (36/64, 56.3%), papillary type (19/64, 29.7%) and clear cell type (4/64, 6.3%). One histological subtype was not reported. In the remaining 57 patients, translocation testing could not be performed, or TFE‐cytogenetics and/or immunohistochemistry results were missing. In this group, the most common RCC histological subtypes were papillary type (21/47, 44.7%) and clear cell type (11/47, 23.4%). Ten histological subtypes were not reported. Estimated 5‐year (5y) EFS and 5y OS of the total group was 70.5% (95% CI = 61.7%‐80.6%) and 84.5% (95% CI = 77.5%‐92.2%), respectively. Estimated 5y OS for localized, regionally advanced, and metastatic disease was 96.8%, 92.3%, and 45.6%, respectively. In conclusion, the registered pediatric patients with RCC showed a reasonable outcome. Survival was substantially lower for patients with metastatic disease. This descriptive study stresses the importance of full, prospective registration including TFE‐testing. What's new? Pediatric renal cell carcinoma (RCC) is a rare malignancy, knowledge of which is based largely on adult RCC. Here, pediatric RCC was retrospectively studied using data from the International Society of Pediatric Oncology – Renal Tumor Study Group (SIOP‐RTSG). Pediatric RCC patients had a 5‐year overall survival rate of 84.5 percent, with notably lower survival for patients with metastatic disease. In pediatric RCC patients tested for transcription factor E3 and EB, 56.3 percent presented with translocation type. The findings highlight the importance of full registration of pediatric RCCs, with information on germline genetics and transcription factor testing. [ABSTRACT FROM AUTHOR]

Abstract Background Blood-born miRNA signatures have recently been reported for various tumor diseases. Here, we compared the miRNA signature in Wilms tumor patients prior and after preoperative chemotherapy according to SIOP protocol 2001. Results We did not find a significant difference between miRNA signature of both groups. However both, Wilms tumor patients prior and after chemotherapy showed a miRNA signature different from healthy controls. The signature of Wilms tumor patients prior to chemotherapy showed an accuracy of 97.5% and of patients after chemotherapy an accuracy of 97.0%, each as compared to healthy controls. Conclusion Our results provide evidence for a blood-born Wilms tumor miRNA signature largely independent of four weeks preoperative chemotherapy treatment.

Wilms tumor is a nephroblastoma, or tumor of the kidney, which occurs in young children. Wilms tumor can be inherited and is associated with a specific chromosomal abnormality, the deletion of a particular region on chromosome 11. Other genitourinary abnormalities are also associated with this region of chromosome 11. The gene thought to be involved in Wilms tumors was identified using the molecular biological technique known as chromosome jumping. Chromosomes are structures composed of deoxyribose nucleic acid (DNA), which code for genes, and contain the information that directs molecules involved in the processes of life. Using probes against DNA sequences which are commonly found in genes that are expressed, several genes from this area on chromosome 11 were isolated. Using this technique of jumping the chromosome, large amounts of DNA sequence that do not contain sequences of interest can be by-passed. The protein that is coded by the gene thought to be involved in Wilms tumors contains sequences that are known as zinc fingers, a structural unit which binds the chemical zinc. Zinc fingers are present in proteins known as transcription factors. Transcription factors bind to DNA, and control the expression of various proteins coded for by the genes. It is not certain that the isolated gene causes Wilms tumors. More than one gene could exist in the chromosomal region that is altered in these tumors. The gene that was isolated was surprisingly not absent or rearranged in 63 out of 65 Wilms tumor samples examined. This isolated gene can also be used to study the embryonic development of kidneys, as Wilms tumors consist of undifferentiated or immature tissue. (Consumer Summary produced by Reliance Medical Information, Inc.)

Abstract Background Wilms tumor (WT) is one of the most common malignancies in childhood. With current therapy protocols up to 90% of patients can be cured, but there is still a need to improve therapy for patients with aggressive WT and to reduce treatment intensity where possible. Prior data suggested a deregulation of the retinoic acid (RA) signaling pathway in high-risk WT, but its mode of action remained unclear. Results The association of retinoid signaling and clinical parameters could be validated in a large independent tumor set, but its relevance in primary nephrectomy tumors from very young children may be different. Reduced RA pathway activity and MYCN overexpression were found in high risk tumors as opposed to tumors with low/intermediate risk, suggesting a beneficial impact of RA especially on advanced WT. To search for possible modes of action of retinoids as novel therapeutic options, primary tumor cell cultures were treated in vitro with all-trans-RA (ATRA), 9cis-RA, fenretinide and combinations of retinoids and a histone deacetylase (HDAC) inhibitor. Genes deregulated in high risk tumors showed opposite changes upon treatment suggesting a positive effect of retinoids. 6/7 primary cultures tested reduced proliferation, irrespective of prior RA signaling levels. The only variant culture was derived from mesoblastic nephroma, a distinct childhood kidney neoplasm. Retinoid/HDAC inhibitor combinations provided no synergistic effect. ATRA and 9cis-RA induced morphological changes suggestive of differentiation, while fenretinide induced apoptosis in several cultures tested. Microarray analysis of ATRA treated WT cells revealed differential expression of many genes involved in extracellular matrix formation and osteogenic, neuronal or muscle differentiation. The effects documented appear to be reversible upon drug withdrawal, however. Conclusions Altered retinoic acid signaling has been validated especially in high risk Wilms tumors. In vitro testing of primary tumor cultures provided clear evidence of a potential utility of retinoids in Wilms tumor treatment based on the analysis of gene expression, proliferation, differentiation and apoptosis.