Our goal in this study is to discover highly specific diagnostic non-invasive biomarkers by analyzing a large cohort (n=660) patient urine samples for different kidney transplant injury phenotypes in pediatric renal transplantation. Kidney transplantation is the treatment of choice for children with end stage kidney disease. Graft survival is limited by the accrual of different injuries such as acute rejection (AR), chronic allograft nephropathy (CAN), and viral infection with the BK virus (BKV), which are indistinguishable by simply monitoring the serum creatinine and require an invasive biopsy for diagnosis of established injury. Urine being an ultrafiltrate of plasma and a direct filtrate of the kidney provides a valuable resource for monitoring graft health and dysfunction. In this proposal, we propose to employ a cutting-edge, comprehensive analysis of the urinary proteome by using recently developed and LC-FT MS/MS-UStags based peptidomics analysis of native urinary peptides and LC-MS/MS based soluble protein analysis of human urine. Availability of state-of-the-art proteomics facility at PNNL and an environment of outstanding bioinformatics with available comprehensive Clinical Database at Stanford will support high-throughput biomarker screening and data analysis for selection of 20 most significant peptides and proteins for differentiating different graft injury phenotypes- AR, CAN, BKV and stable functioning grafts (STA). The selection of the most biologically relevant candidates will be aided by robust integrative proteogenomic data analysis which will use overlapping biopsy microarray data and urine proteomic data from the same patients, collected at the same time-point. Specific and sensitive non-invasive urinary biomarkers discovery for different phenotypes of graft injury will undergo pre-clinical validation by SRM on an independent set of 480 urine samples for diagnosis and prediction. The protein/peptide markers will be useful in developing ELISA assays which can be used for clinical monitoring of graft injury, replacing the invasive transplant biopsy.

Public Health Relevance

In the absence of an effective noninvasive way of diagnosing acute injury, kidney biopsy is the only way to monitor the clinical progress the transplanted kidney. In this study, we propose a comprehensive search for biomarkers that could be later developed as an injury specific clinical test. We are going to use two most powerful proteomic methods to identify these biomarkers which will be first of its kind in the field of transplantation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK083447-05
Application #
8549203
Study Section
Pathobiology of Kidney Disease Study Section (PBKD)
Program Officer
Flessner, Michael Francis
Project Start
2010-08-23
Project End
2014-07-31
Budget Start
2013-08-01
Budget End
2014-07-31
Support Year
5
Fiscal Year
2013
Total Cost
$520,888
Indirect Cost
$119,313
Name
California Pacific Medical Center Research Institute
Department
Type
DUNS #
071882724
City
San Francisco
State
CA
Country
United States
Zip Code
94107
Sigdel, Tara K; Salomonis, Nathan; Nicora, Carrie D et al. (2014) The identification of novel potential injury mechanisms and candidate biomarkers in renal allograft rejection by quantitative proteomics. Mol Cell Proteomics 13:621-31
Delville, Marianne; Sigdel, Tara K; Wei, Changli et al. (2014) A circulating antibody panel for pretransplant prediction of FSGS recurrence after kidney transplantation. Sci Transl Med 6:256ra136
Sigdel, Tara K; Sarwal, Minnie M (2013) Discovery and customized validation of antibody targets by protein arrays and indirect ELISA. Methods Mol Biol 1034:373-84
Sigdel, Tara K; Sarwal, Minnie M (2013) Moving beyond HLA: a review of nHLA antibodies in organ transplantation. Hum Immunol 74:1486-90
Sigdel, Tara K; Lee, Sangho; Sarwal, Minnie M (2011) Profiling the proteome in renal transplantation. Proteomics Clin Appl 5:269-80
Sigdel, Tara K; Sarwal, Minnie M (2011) Recent advances in biomarker discovery in solid organ transplant by proteomics. Expert Rev Proteomics 8:705-15