Project Summary Kidney fibrosis is the final common pathway downstream of most renal injuries that contributes to progressive chronic kidney disease (CKD). Non-coding RNAs regulate kidney fibrosis through direct repression and/or expression of matrix genes and through TGF-β signaling. Our central working hypothesis is that specific circulating and urinary microRNA and long non-coding RNA (EncRNA) are indicators of underlying kidney fibrosis and hence are early biomarkers for CKD progression. We will use the Chronic Renal Insufficiency Cohort Study (CRIC) biosamples and associated data. The study will be conducted in three phases; discovery, replication and an experimental validation phases. Next-generation sequencing will be used to profile the ncRNAs in blood and urine samples from participants exhibiting slow (n=191) and fast (n=192) progression of CKD. Top CKD progression-related ncRNA discoveries will be replicated in 3,088 CRIC study participants using quantitative RT- PCR. The primary renal phenotypes of interest are the slope of change in estimated glomerular filtration rate (eGFR), and either time to end-stage kidney disease (ESRD), or a composite of time to ESRD or a 50% reduction in eGFR. We will employ innovative in vitro experiments and in vivo gain and loss of function experiments in mouse models to identify targets and validate the functional significance of the EncRNA discoveries from human studies. Finally, we will verify the expression level of the top EncRNA discoveries in the microdissected CKD kidney tissues. Identification of specific ncRNA pathways for the progression of CKD will enhance diagnosis, enable risk stratification and lead to hypothesis driven targeted interventions.