Acute inhibition of renal gene expression to prevent nephrotoxicity Prevention of AKI is of paramount importance, but success has been limited when approaches are applied generally. A key reason for these failures is a lack of targets specific to a given cause of AKI. This project utilizes a population genetics model to identify genes associated with sensitivity to four clinically relevant nephrotoxins: gentamicin, colistin, cisplatin, and clofarabine. In this proposal, we seek to validate the success of this population genetics model with acute in vivo siRNA inhibition of renal gene expression. The efficacy of target gene inhibition will be tested in corresponding murine models of drug-induced AKI to determine if this therapeutic strategy mitigates nephrotoxicity. A secondary aim of this project is to discern if acute inhibition of candidate transport genes similarly prevents nephrotoxicity by inhibiting proximal tubular uptake of gentamicin, colistin, cisplatin, or clofarabine. The expected outcome is to determine an optimal nephrotoxicity prevention strategy for each drug. The approach will be paradigm shifting - bringing a drug-specific intervention to each form of renal injury. The precedent for premedication to prevent nephrotoxicity is used in clinical practice as saline is often given to prevent contrast nephropathy. Thus, the siRNA strategies outlined in this proposal hold clinical relevance and the potential to translate to clinical trials. This approach wll yield multiple new molecular therapeutics specific to a variety of nephrotoxins, ready for rapid translation to clinical trials. My long-term goal is to become a physician scientist using large databases to uncover and validate genetic biomarkers and therapeutic targets which will readily translate to clinical care. Through this K08 award, I will learn new techniques including: analytic methods for genetic databases, animal model experimentation, laser micro-dissection (LMD), and in vivo siRNA knockdown. The acquired techniques will allow me to complete the above aims, but also provide the foundation to successfully compete for future R01 funding to: 1) uncover biomarkers from large genetic databases, 2) determine nephron segment specific gene expression with LMD of biopsy tissue, and 3) test mechanistic pathways and therapeutic targets in vivo with siRNA inhibition. These techniques can be applied to the improvement of renal care for many conditions. Further, the mentoring team I have assembled will advise me on the translation of these siRNA constructs to future clinical trials. My mentors and advisors at the Indiana University School of Medicine (IUSM) have a previous history of translating their pre-clinical studies with siRNA to successful phase 1 and 2 clinical trials. The rich environment at IUSM is sure to aid in my development as a physician scientist. With a dual appointment in the divisions of nephrology and clinical pharmacology, I am exposed to a wide range of collaborators in nearly every primary division. My division heads, Sharon Moe and David Flockhart, effectively protect my time as my clinical obligations are limited to 4 weeks of inpatient service and 1/2 day of clinic. They have provided ample laboratory space, start-up funds, and a technician. Our school renewed its NIH Clinical Translational Science Award (the Indiana CTSI) in 2013. I have already reaped the benefits of this advantage by obtaining a CTSI biomedical researcher grant. Finally, my mentors, Pierre Dagher and Todd Skaar, are incredibly supportive. The two of them provide a balance so I learn skills in both mouse models of acute kidney injury and pharmacogenomics analysis / validation. In summary, the proposed project builds logically on my fellowship training in nephrology and clinical pharmacology. My transition to Indiana University School of Medicine makes a great deal of sense not only because of its institutional commitment to me, but also what I can learn from my selected mentors, Drs. Pierre Dagher, Todd Skaar, and David Flockhart in order to address my specific aims and hypothesis. With ties to clinical pharmacology and nephrology, I am poised to apply novel strategies to nephrotoxicity prevention and other kidney diseases.
Acute kidney injury is a common unintended consequence of prescribed medications that causes marked increases in mortality, hospital stay, and medical expenditures. Drug-induced kidney toxicity not only contributes to acute kidney injury, but also results in discontinuation of or delay in treatment of malignancy and other life threatening conditions. This proposal aims to test whether siRNA gene expression knockdown can be used as a molecular therapeutic to prevent drug-induced acute kidney injury.
