Project description:PTBA has been published to increase renal tubular cell proliferation, increased survival, and increased renal functional recovery in fish and various models of murine models of acute kidney injury. Immunohistological analyses suggested increased cell proliferation is accompanied by increased epithelial-to-mesenchymal transition in the RTECs. In order to elucidate pathways responsible for the increased repair response after compound treatment, larval zebrafish were given AKI and treated with PTBA analogue, UPHD25 or DMSO. Results suggests that epithelial-related genes were downregulated while mesenchymal-related genes were upregulated with injury and compound treatment. Results further validate our immunohistological finding that our compound increase post-AKI repair by increasing EMT in renal tubular cells.
Project description:Renal hypoxia is widespread in acute kidney injury (AKI) of various aetiologies. Hypoxia adaptation, conferred through the hypoxia-inducible factor (HIF), appears to be insufficient. Here we show that HIF activation in renal tubules through Pax8-rtTA-based inducible knockout of von Hippel-Lindau protein (VHL-KO) protects from rhabdomyolysis-induced AKI. In this model, histological observations indicate that injury mainly affects proximal convoluted tubules, with 5% necrosis at d1 and 40% necrosis at d2. HIF-1alpha up-regulation in distal tubules reflects renal hypoxia. However, lack of HIF in proximal tubules suggests insufficient adaptation by HIF. AKI in VHL-KO mice leads to prominent HIF activation in all nephron segments, as well as to reduced serum creatinine, serum urea, tubular necrosis, and apoptosis marker caspase-3 protein. At d1 after rhabdomyolysis, when tubular injury is potentially reversible, HIF mediated protection in AKI is associated with activated glycolysis, cellular glucose uptake and utilization, autophagy, vasodilation, and proton removal as demonstrated by qPCR, pathway enrichment analysis and immunohistochemistry. Together, our data provide evidence for a HIF-orchestrated multi-level shift towards glycolysis as a major mechanism for protection against acute tubular injury. All experiments were carried out in transgenic mice in which selective renal tubular VHL knockout (VHL-KO) was inducible by doxycycline (Reference: Mathia S, Paliege A, Koesters R, Peters H, Neumayer HH, Bachmann S, Rosenberger C. Action of hypoxia-inducible factor in liver and kidney from mice with Pax8-rtTA-based deletion of von Hippel-Lindau protein. Acta Physiol (Oxf). 2013; 207(3):565-76.). Four groups of animals were used: 1) controls: untreated mice; 2) VHL-KO: injected with doxycycline (0.1 mg per 10 g body weight SC), 4 days prior to sacrifice; 3) AKI: rhabdomyolysis; 4) VHL-KO/AKI: doxycycline plus rhabdomyolysis. To induce AKI, 50% glycerol (0.05 ml per 10 g body weight) was injected IM into the left hind limb under isoflurane narcosis. Drinking water was withdrawn between 20 h prior and 24 h after glycerol injection.
Project description:Microarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers. AKI biopsies sample names and CEL files are from GSE21374. All consenting renal transplant patients undergoing biopsies for cause as standard of care between 09/2004 and 10/2007 at the university of Alberta or between 11/2006 and 02/2007 at the University of Illinois were included in the analysis. In addition to the cores required for standard histopathology, we collected one core for gene expression studies. the relationship between gene expression in the biopsy and subsequent graft loss was analyzed. This dataset is part of the TransQST collection.
Project description:Renal hypoxia is widespread in acute kidney injury (AKI) of various aetiologies. Hypoxia adaptation, conferred through the hypoxia-inducible factor (HIF), appears to be insufficient. Here we show that HIF activation in renal tubules through Pax8-rtTA-based inducible knockout of von Hippel-Lindau protein (VHL-KO) protects from rhabdomyolysis-induced AKI. In this model, histological observations indicate that injury mainly affects proximal convoluted tubules, with 5% necrosis at d1 and 40% necrosis at d2. HIF-1alpha up-regulation in distal tubules reflects renal hypoxia. However, lack of HIF in proximal tubules suggests insufficient adaptation by HIF. AKI in VHL-KO mice leads to prominent HIF activation in all nephron segments, as well as to reduced serum creatinine, serum urea, tubular necrosis, and apoptosis marker caspase-3 protein. At d1 after rhabdomyolysis, when tubular injury is potentially reversible, HIF mediated protection in AKI is associated with activated glycolysis, cellular glucose uptake and utilization, autophagy, vasodilation, and proton removal as demonstrated by qPCR, pathway enrichment analysis and immunohistochemistry. Together, our data provide evidence for a HIF-orchestrated multi-level shift towards glycolysis as a major mechanism for protection against acute tubular injury.
Project description:Microarray analysis of human kidneys with acute kidney injury (AKI) has been limited because such kidneys are seldom biopsied. However, all kidney transplants experience AKI, and early kidney transplants without rejection are an excellent model for human AKI: they are screened to exclude chronic kidney disease, frequently biopsied, and have extensive follow-up. We used histopathology and microarrays to compare indication biopsies from 28 transplants with AKI to 11 pristine protocol biopsies of stable transplants. Kidneys with AKI showed increased expression of 394 injury-repair response associated transcripts, including many known epithelial injury molecules (e.g. ITGB6, LCN2), tissue remodeling molecules (e.g. VCAN), and inflammation molecules (S100A8, ITGB3). Many other genes also predict the phenotype, depending on statistical filtering rules, including AKI biomarkers as HAVCR1 and IL18. Most mouse orthologs of the top injury-repair transcripts were increased in published mouse AKI models. Pathway analysis of the injury-repair transcripts revealed similarities to cancer, development, and cell movement. The injury-repair transcript score AKI kidneys correlated with reduced function, future recovery, brain death, and need for dialysis, but not future graft loss. In contrast, histologic features of "acute tubular injury" did not correlate with function or with the molecular changes. Thus the injury-repair associated transcripts represent a massive coordinate injury-repair response of kidney parenchyma to AKI, similar to mouse AKI models, and provide an objective measure for assessing the severity of AKI in kidney biopsies and validation for the use of many AKI biomarkers.
Project description:Contrast-induced acute kidney injury (CI-AKI) is typically defined by an increase in serum creatinine (SCr) after intravascular administration of contrast medium. Since creatinine is an unreliable indicator for acute changes in kidney function, an early biomarkers for CI-AKI diagnosis is important for initiating therapy.We assessed the hypothesis that circulating microRNAs (miRNAs) could be served as potential biomarkers to early detect CI-AKI.The rat model of acute kidney injury was developed as we previously described. We first detect miRNA profile of plasma and kidney tissue using Agilent microarray platform. 3 miRNA species with > 1.5-fold increase in plasma samples of CI-AKI rats, including miRNA-30a, miRNA-30e and miRNA-188, were selected as candidate miRNAs of potential biomarkers. 24 rats were randomly divided into 2 groups (CI-AKI group and control group), each with 4 subgroups (n=3). Peripheral blood and kidney samples were harvest at 8h after contrast medium/normal saline administration. Total RNA sample from each rat in the same subgroup was combined together as pooled sample for further test. The Agilent microarray platform was adapted to profile the miRNA spectra.
Project description:18 zero-hour and 18 selected post-transplant (Tx) biopsy samples from 18 kidney allografts (8 acute kidney injury (AKI), 10 PBx - protocol biopsies - controls) were analyzed by using the Affymetrix GeneChipM-BM-. miRNA 3.0 Array. Comparison between control group (protocol biopsies) and indication biopsies with histological lesions of acute tubular necrosis without rejection (ATN).
Project description:18 zero-hour and 18 selected post-transplant (Tx) biopsy samples from 18 kidney allografts (8 acute kidney injury (AKI), 10 PBx - protocol biopsies - controls) were analyzed by using the Affymetrix GeneChip® Human Gene 2.0 ST Array. comparison between control group (protocol biopsies) and indication biopsies with histological lesions of acute tubular necrosis without rejection (ATN)
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:Transcriptional profiling of mouse kidney tissue comparing control untreated mice with mice treated with cisplatin. The latter makes kidney failure. Goal was to identify the alterations of N6-methyladenosine (m6A) RNA profiles in cisplatin-induced acute kidney injury (AKI) in mice.