Autosomal dominant polycystic kidney disease (ADPKD) affects 1/1000 of the US population. The disease is characterized by the replacement of normal renal tissue by thousands of cysts and results in ESRD in approximately 50%. In this competitive renewal, we seek to follow-up on observations recorded during the most recent award. It is our central hypothesis that ADPKD results from decreased activity of the PC-1/PC-2 receptor/channel signaling complex below some critical threshold. We speculate that a variety of genetic, environmental and stochastic factors can combine to reduce the activity of the PC-1/PC-2 complex (and its effector pathways) to a level that can initiate a pathologic state. It is likely that the complex interactions between the various factors account for the significant clinical variability that is observed. In keeping with the original philosophy of this project, we propose to use novel genetic strategies to test this hypothesis. We seek to use a multi-disciplinary approach that utilizes expert clinical observations and human clinical samples, novel in vitro cell culture systems, and unique mouse models to address the problem. This grant has three aims. In the first, we will test the hypothesis that the nature of genetic mutations influences disease severity using in vitro and in vivo model systems. We will determine the sequence of mutant RNA molecules that correspond to DNA sequence mutations identified in a subset of individuals with interesting phenotypes and genotypes in our clinical database. Expression constructs that contain cDNAs that correspond to the mutant mRNAs will be expressed using our novel in vitro tubulogenesis cell culture systems and assayed for a variety of PC-1 related functional properties. A subset of mutations will be introduced into the mouse germline through homologous recombination using recombineering techniques and mouse Pkd1 BACs with the goal of making a set of hypomorphic alleles that can be combined in various combinations with our Pkd1 null allele. In the second aim, we will test the hypothesis that hemizygosity is sufficient for disease under some conditions. We will examine hepatic cysts, which are nearly 100% penetrant in our Pkd1 +/- mice, for acquired mutations of Pkd1. In the final aim, we will examine the effects of acquired loss of Pkd1 at various developmental and post-developmental timepoints and in a tissue-selective manner. A line of mice with an inducible null allele created by the PI's laboratory (Pkd1[cond]) will be crossed with a variety of Cre-expressing mouse lines. These studies should improve our understanding of the pathogenesis of this disease and provide new tools for testing potential therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DK048006-15
Application #
7479586
Study Section
Cellular and Molecular Biology of the Kidney Study Section (CMBK)
Program Officer
Rasooly, Rebekah S
Project Start
1994-05-01
Project End
2010-07-31
Budget Start
2008-08-01
Budget End
2010-07-31
Support Year
15
Fiscal Year
2008
Total Cost
$495,327
Indirect Cost
Name
Johns Hopkins University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Liu, Yang; Pejchinovski, Martin; Wang, Xueqi et al. (2018) Dual mTOR/PI3K inhibition limits PI3K-dependent pathways activated upon mTOR inhibition in autosomal dominant polycystic kidney disease. Sci Rep 8:5584
Liu, Dongyan; Wang, Connie J; Judge, Daniel P et al. (2014) A Pkd1-Fbn1 genetic interaction implicates TGF-? signaling in the pathogenesis of vascular complications in autosomal dominant polycystic kidney disease. J Am Soc Nephrol 25:81-91
Ferraz, Renato Ribeiro Nogueira; Fonseca, Jonathan Mackowiak; Germino, Gregory George et al. (2014) Determination of urinary lithogenic parameters in murine models orthologous to autosomal dominant polycystic kidney disease. Urolithiasis 42:301-7
Outeda, Patricia; Huso, David L; Fisher, Steven A et al. (2014) Polycystin signaling is required for directed endothelial cell migration and lymphatic development. Cell Rep 7:634-44
Menezes, Luis F; Zhou, Fang; Patterson, Andrew D et al. (2012) Network analysis of a Pkd1-mouse model of autosomal dominant polycystic kidney disease identifies HNF4? as a disease modifier. PLoS Genet 8:e1003053
Pei, York; Lan, Zheng; Wang, Kairong et al. (2012) A missense mutation in PKD1 attenuates the severity of renal disease. Kidney Int 81:412-7
Steigelman, Katherine A; Lelli, Andrea; Wu, Xudong et al. (2011) Polycystin-1 is required for stereocilia structure but not for mechanotransduction in inner ear hair cells. J Neurosci 31:12241-50
Miller, Michelle M; Iglesias, Diana M; Zhang, Zhao et al. (2011) T-cell factor/?-catenin activity is suppressed in two different models of autosomal dominant polycystic kidney disease. Kidney Int 80:146-53
Shillingford, Jonathan M; Piontek, Klaus B; Germino, Gregory G et al. (2010) Rapamycin ameliorates PKD resulting from conditional inactivation of Pkd1. J Am Soc Nephrol 21:489-97
Garcia-Gonzalez, Miguel A; Outeda, Patricia; Zhou, Qin et al. (2010) Pkd1 and Pkd2 are required for normal placental development. PLoS One 5:

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