Application of the Sleeping Beauty Transposon System to Identify Regulatory Genes Driving ADPKD Cystogenesis and Phenotypic Heterogeneity
Abstract
This proposal aims to identify new genes that influence the severity of autosomal dominant polycystic kidney disease (ADPKD), the most common genetic renal disease worldwide. Our study will specifically address the Fiscal Year 2016 Peer Reviewed Medical Research Program (PRMRP) topic area of Polycystic Kidney Disease (PKD). The program identified research on the underlying pathobiology and molecular mechanism of PKD as a gap and priority research area, which this research addresses. Further, this research will also provide novel insight into potential therapeutic targets that can lead to the development of improved treatment strategies for PKD patients, another priority area identified by the Defense Health Agencies. ADPKD is a severe genetic disorder affecting ~1:500 individuals and is characterized by the growth of fluid-filled cysts, leading to crowding of the normal kidney tissue and eventual renal failure. Fortunately, the genes causing renal cystogenesis are known and hence patients and family members can be genetically diagnosed. However, a critical problem in the field is that it is unknown what drives the heterogeneity in disease presentation, meaning whether kidney failure occurs as a young or elderly adult, and what the exact mechanisms are that cause cyst development. It is widely accepted in the field that mutations to additional genes likely are responsible for disease variability and that identification of these genes would shed light on the open question of what pathways are associated with cystogenesis. Here, we will use a systematic large-scale in vivo approach, using a mouse model of the disease to identify genes that drive cystogenesis and may contribute to the observed phenotypic heterogeneity. We will further confirm the likelihood of these genes being disease modifiers in ADPKD patients and in cellular systems. To pinpoint the genes driving cyst development, we will use a mouse model that generally does not have ADPKD, but is prone to the disease development because it misses one copy of one of the disease genes. We will cross this mouse model with a different model that triggers disruption of random genes in the genome. In our ADPKD model, this will result in additional genetic insults that could link to PKD-related pathways and hence initiate cystogenesis in our susceptible model. The genes that were disrupted can then be identified by DNA isolation from the cystic cells and sequencing. As confirmatory experiments, we will then test whether the identified genes are also found to be mutated in ADPKD patients with either mild or very severe disease and whether their disruption causes ADPKD cellular phenotypes in various cell lines. This project is innovative as it takes an unbiased, financially cost-effective, and targeted approach to identify these critical modifier genes that will provide insight into the mechanisms of PKD and platforms for new treatments. Current approaches taken to answer the same question require either extremely large clinical cohorts that are well characterized and hence are very costly or utilize methods in murine models that are not aimed to identify single genes, but rather large chromosomal regions or particular pathways. Ultimately, results obtained from this research will have great translational impact: (a) Identification of genes driving cyst initiation/progression will help to better understand the pathogenesis of ADPKD. (b) Novel genes/pathways identified as influencing cyst progression will provide new avenues for single and/or additive therapeutic interventions. (c) Gene products of identified loci can be evaluated as potential new or supplemental PKD biomarkers. (d) Genetic testing of modifier genes will be of prognostic value. (e) Based on an ADPKD individual s modifier genotype, the suitability for and success of various treatment trials with differing targets can be determined.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 07, 2017
- Source ID
- W81XWH1710107
Entities
People
- Katharina Hopp
Organizations
- United States Army
- University of Colorado Denver