Project description:Background: The mammalian kidneys maintain salt and water homeostasis for proper electrolyte balance and hydration. As the glomerular filtrate passes through the nephron and into the renal medulla, electrolytes, water, and urea are reabsorbed through the concerted actions of solute carrier channels and aquaporins located at various positions along the nephron and in the outer and inner medulla. Renal epithelial cells develop from Pax2 positive proliferating stem cells that suppress Pax2 expression once differentiated into mature proximal and distal tubules, but continue to express the related Pax8 protein. The collecting tubules and renal medulla are derived from a Pax2 positive ureteric bud epithelia that continue to express Pax2 and Pax8 in adult kidneys. Despite the necessity for Pax2 in renal development, functions for Pax2 or Pax8 in adult renal epithelia have not been established. Methods: In this report, we deleted either Pax2, Pax8, or both genes in adult mice and examined the phenotypes and changes in gene expression patterns. The mechanism of Pax8 mediated activation of potential target genes was described in inner medullary collecting duct cells. Results: Mice with induced deletions of both Pax2 and Pax8 exhibit severe polyuria that can be attributed to significant changes in the expression of solute carriers, such as the urea transporter UTA1, and aquaporins within the inner and outer medulla. Furthermore, Pax8 expression is induced by high salt in collecting duct cells and activates the UTA1 gene by recruiting a histone methyltransferase complex to the promoter. Conclusions: These data uncover novel functions for Pax proteins, in adult renal epithelia, that are essential for retaining water and concentrating urine.
Project description:Pax2 and Pax8 are homologous transcription factors required for kidney development and medullary urine concentration. However, their function in proximal tubule homeostasis and response to acute kidney injury is unknown. Mice with proximal tubules consisting of a mosaic of wild-type and Pax2/8 mutant proximal tubules cells were generated. Gene expression of mutant and wild-type proximal tubule cells was compared under homeostatic conditions using single-nucleus RNA sequencing.
Project description:Activation of lineage-specific gene expression programs is mediated by the sequence-specific recruitment of transcriptional coactivators to chromatin. This occurs via interaction with lineage specific DNA binding transcription factors. The lineage factor PAX8 drives essential gene expression in ovarian cancer cells and is required for tumor proliferation. However, the molecular details surrounding co-factor recruitment and specific activation of transcription by PAX8 remain unknow. Here, we identify an important functional interaction between PAX8 and the Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex. We show that PAX8 can recruit SWI/SNF complexes to DNA, where they function to open chromatin and facilitate expression of PAX8 target genes. Genetic deletion of PAX8 results in loss of SWI/SNF from PAX8 bound enhancers, loss of expression of associated target genes, and reduced proliferation. These results can be phenocopied by pharmacological inhibition of SWI/SNF ATPase activity. These data indicate that PAX8 mediates the expression of an essential ovarian cancer proliferative program in part by the recruitment of chromatin remodelers.
Project description:Activation of lineage-specific gene expression programs is mediated by the sequence-specific recruitment of transcriptional coactivators to chromatin. This occurs via interaction with lineage specific DNA binding transcription factors. The lineage factor PAX8 drives essential gene expression in ovarian cancer cells and is required for tumor proliferation. However, the molecular details surrounding co-factor recruitment and specific activation of transcription by PAX8 remain unknow. Here, we identify an important functional interaction between PAX8 and the Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodeling complex. We show that PAX8 can recruit SWI/SNF complexes to DNA, where they function to open chromatin and facilitate expression of PAX8 target genes. Genetic deletion of PAX8 results in loss of SWI/SNF from PAX8 bound enhancers, loss of expression of associated target genes, and reduced proliferation. These results can be phenocopied by pharmacological inhibition of SWI/SNF ATPase activity. These data indicate that PAX8 mediates the expression of an essential ovarian cancer proliferative program in part by the recruitment of chromatin remodelers.
Project description:The mammalian kidney develops in three successive steps from the initial pronephros via the mesonephros to the adult metanephros. Although the nephric lineage is specified during pronephros induction, no single regulator, including the transcription factor Pax2 or Pax8, has yet been identified to control this initial phase of kidney development. In this paper, we demonstrate that mouse embryos lacking both Pax2 and Pax8 are unable to form the pronephros or any later nephric structures. In these double-mutant embryos, the intermediate mesoderm does not undergo the mesenchymal-epithelial transitions required for nephric duct formation, fails to initiate the kidney-specific expression of Lim1 and c-Ret, and is lost by apoptosis 1 d after failed pronephric induction. Conversely, retroviral misexpression of Pax2 was sufficient to induce ectopic nephric structures in the intermediate mesoderm and genital ridge of chick embryos. Together, these data identify Pax2 and Pax8 as critical regulators that specify the nephric lineage.
Project description:Heterozygous and homozygous Pax2 E11.5 embryos were collected and the intermediate mesoderm was dissected and dispersed into single cells. The Pax2 positive cells also expressed EGFP, which was knocked into the Pax2 locus. EGFP positive cells were sorted by FACS and RNA isolated. We compared RNA expression levels in EGFP positive cells from Pax2 null and Pax2 heterozygote embryos.
Project description:PAX8 transcriptional profiling of rat PCCL3 cells comparing wild type cells with PAX8 silenced cells and scramble treated with PAX8 silenced cells
Project description:PAX2 is one of nine PAX genes that regulate tissue development and cellular differentiation in embryos. PAX2 promotes cell proliferation, oncogenic transformation, cell lineage specification, migration, and survival. In our previous study, we found that PAX2 is highly expressed in low-grade ovarian serous carcinoma, but its expression in clear cell, endometrioid, and mucinous cell ovarian carcinomas have not been studied. More importantly, the functional role of PAX2 in ovarian cancer is not known. Downregulation of PAX2 in PAX2-expressing ovarian cancer cells inhibits cell proliferation and migration. This growth inhibition is due to the upregulation of the tumor suppressor gene G0S2 and subsequent induction of apoptosis. The PAX2 pathway thus represents a potential therapeutic target for PAX2-expressing ovarian carcinomas. Knockdown PAX2 expression in these cell lines was achieved by lentiviral shRNAs targeting the PAX2 gene. PAX2 stable knockdown cells were characterized for cell proliferation, migration, apoptosis, and gene expression profiles.
Project description:We performed a genomewide differential gene expression analysis by Ion AmpliSeqTM Transcriptome sequencing that targets more than 20,000 human genes to gain insights into the genes and pathways involved in the onset of familial steroid-resistant Focal Segmental Glomerulosclerosis (FSGS) driven by the presence of a heterozygous mutation in the PAX2 gene (PAX2G189R/+). Using a stepwise protocol, we differentiated control and PAX2G189R/+ induced pluripotent stem cells into podocytes and we performed whole-transcriptomic analysis on control and patient cells on days 6, 13 and 18 of differentiation. Our data indicated that the PAX2 mutation mainly affects the focal adhesion pathway and the expression of IGF1, a PAX2 target, in adult podocytes that are more susceptible to cell death by environmental triggers.