Project description:A quarter of patients with acute decompensated heart failure (ADHF) experience acute kidney injury (AKI), an abrupt loss of kidney function that doubles the risk of death at one-year. There is a critical need to identify early markers for AKI in ADHF, however, no protein candidates have been validated as diagnostic or prognostic biomarkers in this setting. We aimed to identify novel candidate protein biomarkers by quantifying changes in protein expression in the kidney that occur during ADHF development and recovery in an ovine model. Relative quantitative protein profiling was performed using Sequential Window Acquisition of All Theoretical Mass Spectrometry (SWATH-MS) in kidney cortex from healthy control sheep (n=5), sheep with established rapid pacing-induced ADHF (n=8) and sheep after ~4 weeks recovery from ADHF (n=7). Of 790 proteins quantified, we identified 17 candidate kidney injury markers, one potential marker of kidney recovery and two markers of long-term renal impairment that were differentially expressed between groups (1.2-2.6 fold-change, p<0.05). Differentially expressed proteins were enriched in pro-inflammatory signaling pathways: Glycoprotein VI (activated during ADHF development, adjusted p<0.01) and acute phase response (repressed during recovery from ADHF, p<0.01). This research identified 20 candidate protein markers of kidney injury, including 6 promising candidates supported by existing evidence and 14 novel candidates never implicated in AKI. Early awareness of AKI in ADHF through the use of biomarkers has the potential to reduce mortality and improve outcomes for these at-risk patients.
Project description:Histologic assessment of kidney transplant biopsies relies on cortex rather than medulla, but for microarray studies, the proportion cortex in a biopsy is typically unknown and could affect the molecular readings. The present study aimed to develop a molecular estimate of proportion cortex in biopsies and examine its effect on molecular diagnoses. Microarrays from 26 kidney transplant biopsies divided into cortex and medulla components and processed separately showed that many of the most significant differences were in glomerular genes e.g. NPHS2, NPHS1, CLIC5, PTPRO, PLA2R1, PLCE1, PODXL and REN. Using NPHS2 (podocin) to estimate proportion cortex, we examined whether proportion cortex influenced molecular assessment in the Molecular Microscope Diagnostic System. In 1190 unselected kidney transplant indication biopsies (Clinicaltrials.govNCT01299168), only 11% had <50% cortex. Molecular scores for ABMR, TCMR, and injury were independent of proportion cortex. Rejection was diagnosed in many biopsies that were mostly or all medulla. Agreement in molecular diagnoses in paired cortex/medulla samples (23/26) was similar to biological replicates (32/37). We conclude that NPHS2 expression can estimate proportion cortex; that proportion cortex has little influence on molecular diagnosis of rejection, and that, although histology cannot assess medulla, rejection does occur in medulla as well as cortex. We studied 26 pairs of cortex/medulla biopsies from 26 patients (4 unpaired), characterizing the clinical and histological features, and defined the mRNA phenotype with Affymetrix expression microarrays. We also studied 37 pairs of biopsies from biological replicates and 12 pairs from technical replicates. This dataset is part of the TransQST collection.
Project description:O-GlcNAcylation is a global post translational modification. The purpose of this study is to investigate the role of O-GlcNAcylation in mice kidney proximal tubules. We used drug-inducible proximal tubular cells specific O-GlcNAc transferase (Ogt) KO mice (PTEC-Ogt KO). In this proteomic analysis, we compared kidney cortex from fasted PTEC-Ogt KO and Control mice.