Project description:The highly heterogeneous nature of the kidney's tubular epithelium has made it challenging to identify unique, cell-specific pathways particularly when renal injury causes the loss of fiduciary landmarks. Here, we combine a cell-specific luciferase reporter system with a chemo-selective substrate to identify specific Òat riskÓ tissues. We demonstrate that this platform system has the power to identify both cell-specific pathophysiological events and cell-specific transcriptional changes and consequently can identify novel therapeutic targets. Using the kidney ischemia-reperfusion model (iAKI), we found that lipid peroxidation mirrored H2O2 generation but with entirely different timing and sensitivity to ischemia depending on the nephron segment. We found the collecting duct demonstrated intensive ROS generation and transcriptional analysis demonstrated mitochondrial distress. In fact, pretreatment with a single bolus of a mitochondrial antioxidant, MitoTEMPO delayed ROS generation and significantly reduced acute oxidative stress associated injury. These data demonstrate that iAKI differentially targets different nephron segments, demonstrating the complexity of kidney injury includes multiple segments. Our in vivo ROS detection system can explore complex injuries in heterogeneous organs by leveraging image guidance for tissue interrogation.
Project description:Ischemic preconditioning is effective in limiting subsequent ischemic acute kidney injury in experimental models. microRNAs are an important class of post-transcriptional regulator and show promise as biomarkers of kidney injury. An evaluation was performed of the time- and dose-dependent effects of ischemic preconditioning in a rat model of functional (bilateral) ischemia-reperfusion injury. A short, repetitive sequence of ischemic preconditioning resulted in optimal protection from subsequent ischemia-reperfusion injury. A detailed characterization of microRNA expression in ischemic preconditioning/ischemia-reperfusion injury was performed by small RNA-Seq.
Project description:Ischemic preconditioning is effective in limiting subsequent ischemic acute kidney injury in experimental models. microRNAs are an important class of post-transcriptional regulator and show promise as biomarkers of kidney injury. An evaluation was performed of the time- and dose-dependent effects of ischemic preconditioning in a rat model of functional (bilateral) ischemia-reperfusion injury. A short, repetitive sequence of ischemic preconditioning resulted in optimal protection from subsequent ischemia-reperfusion injury. A detailed characterization of microRNA expression in ischemic preconditioning/ischemia-reperfusion injury was performed by Exiqon miRCURY microRNA array.
Project description:Epigenetic modifications, such as cytosine methylation and histone modification, have been shown involved in the pathology of ischemic brain injury. Recent works have implicated 5-hydroxymethylcytosine (5hmC), a DNA base derived from 5-methylcytosine (5mC) through the oxidation by Ten-Eleven Translocation (TET) enzymes, in DNA methylation-related plasticity. In this study we show that 5hmC abundance could be induced to increase by ischemia injury. Genome-wide profiling of 5hmC identified differentially hydroxymethylated regions (DhMRs) associated with ischemic injury and DhMRs were found enriched among the genes involved in cell junction, neuronal morphogenesis and neurodevelopment. These data together suggest that 5hmC modification could serve as a potential therapeutic target for the treatment of ischemic stroke. To determine the genome-wide 5hmC distribution in both ischemic injury (I/R) and control mice (C57BL/6), we employed a previously established chemical labeling and affinity purification method, coupled with high-throughput sequencing (Song et al, Nature Biotechnology, 2011). The ischemic or matched control brain tissues from three pairs of ischemic mice and control mice were used for the analyses.
Project description:This SuperSeries is composed of the following subset Series: GSE23160: Global transcriptomic profiling of ischemic/reperfusion injury in an in vivo wild-type mouse model. GSE23162: Global transcriptomic profiling of ischemic/reperfusion injury in an in vivo Gpx1 -/- transgenic mouse model. Refer to individual Series
Project description:Background: Previous study showed that stroke may be a potential first sign of neoplasia. But the relationship between them remains unclear. Besides, ischemic stroke is a complex brain disease, which involves cell death or complex immune regulation. Thus, it is necessary to reveal the association of tumor immune microenvironment and cell death with ischemic stroke. Methods: Here, a photothrombosis-induced ischemic injury models of brain and skull was established. We compared and analyzed the pattern of gene expression profile between brain and skull after ischemic injury by transcriptome analysis. Further, we investigated the enrichment of relevant differential genes in cancer pathways and cell death pathways, and analyzed changes in the immune microenvironment after ischemic injury. Moreover, the pan-cancer genomic and prognosis analysis of ischemic injury related gene set were performed. Results: The results showed that the gene expression patterns were different in temporal and spatial locations after ischemic injury. We found that the effect on the transcriptome of the brain after skull ischemic injury was particularly large, but it could be recovered in a short period, while the effect on the skull after brain ischemic injury was long-lasting. The expression of genes related to ischemic injury is also associated with cell death and cancer hallmark pathways. In addition, changes in the abundance of immune cells indicate that brain ischemic injury may disrupt its immune microenvironment for a longer time, while skull can better balance the stability of immune microenvironment. Moreover, the brain ischemic injury-related gene sets are highly correlated with a variety of tumors, especially GBM, KIRC, LGG and UVM after stroke have a greater risk of death. Conclusion: This study gives us a new understanding of the role of the skull in brain ischemic injury, and reveals the association of tumor immune microenvironment and cell death with ischemic stroke.
Project description:Female sex protects against development of acute kidney injury (AKI). While sex hormones may be involved in protection, the role of differential gene expression is unknown. We conducted gene profiling in male and female mice with or without kidney ischemia-reperfusion injury. Mice underwent bilateral renal pedicle clamping (30 min), and tissues were collected 24 hours after reperfusion. RNA-sequencing was performed on proximal tubules and kidney endothelial cells. Female mice were resistant to ischemic injury compared to males, determined by plasma creatinine, histologic scores, neutrophil infiltration, and extent of apoptosis. Sham mice had sex-specific gene disparities in proximal tubule and endothelium, and male mice showed profound gene dysregulation with ischemia-reperfusion compared to females. After ischemia proximal tubules from females exhibited smaller increases compared to males in injury-associated genes Lcn2, Havcr1, and Krt18, and no upregulation of Sox9 or Krt20. Endothelial upregulation of adhesion molecules and cytokines/chemokines occurred in males, but not females. Upregulated genes in male ischemic proximal tubules were linked to tumor necrosis factor and Toll-like receptor pathways, while female ischemic proximal tubules showed upregulated genes in pathways related to transport. The data suggest that sex-specific gene expression profiles in male and female proximal tubule and endothelium may underlie disparities in susceptibility to AKI.
Project description:miRNA profiling of kidney tissue from C57BL/6 mice that received a 30 minute ischemic injury compared with control kidney tissue from mice that received sham operation only. Two condition experiment - sham and ishemic injury (IRI). Eight time points were measured using pooled samples from three mice.