Effect of tubular IKKb deletion in acute ischemic kidney injury
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE207430 | GEO | 2022/07/09
REPOSITORIES: GEO
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Project description:Effect of tubular IKKb deletion in acute ischemic kidney injury
| PRJNA855461 | ENA
Project description:The mechanistic target of rapamycin mTORC1 is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTOR inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By utilizing constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in counter-current multiplication and urine concentration. Although mTORC2 partially compensated the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice, and caused pronounced apoptosis, diminished proliferation rates and delayed recovery. These findings identify mTORC1 as an essential regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. Pharmacological inhibition of mTORC1 likely affects tubular homeostasis, and may be particularly deleterious if the kidney is exposed to acute injury. Furthermore, the combined inhibition of mTORC1 and mTORC2 may increase the susceptibility to renal damage. Raptor fl/fl*KspCre and Raptor fl/fl animals were sacrificed at P14 before the development of an overt functional phenotype. Kidneys were split in half and immediately snap frozen in liquid nitrogen.
2014-06-09 | E-GEOD-54417 | biostudies-arrayexpress
Project description:NF-κB is a key regulator of innate and adaptive immunity and is implicated in the pathogenesis of acute kidney injury (AKI). The cell type-specific functions of NF-κB in the kidney are unknown; however, the pathway serves distinct functions in immune and tissue-parenchymal cells. We analyzed tubular epithelial-specific NF-κB signaling in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. NF-κB reporter activity and nuclear localization of phosphorylated NF-κB subunit p65 analyses in mice revealed widespread NF-κB activation in renal tubular epithelia and in interstitial cells following IRI that peaked at 2-3 days after injury. To genetically antagonize tubular epithelial NF-κB activity, we generated mice expressing the human NF-κB super-repressor IκBα∆N in renal proximal, distal, and collecting duct epithelial cells. These mice were protected from IRI-induced AKI, as indicated by improved renal function, reduced tubular apoptosis, and attenuated neutrophil and macrophage infiltration. Tubular NF-κB-dependent gene expression profiles revealed temporally distinct functional gene clusters for apoptosis, chemotaxis, and morphogenesis. Primary proximal tubular cells isolated from IκBα∆N-expressing mice exposed to hypoxia-mimetic agent cobalt chloride were protected from apoptosis and expressed reduced levels of chemokines. Our results indicate that postischemic NF-κB activation in renal-tubular epithelia aggravates tubular injury and exacerbates a maladaptive inflammatory response.
2016-09-17 | GSE87024 | GEO
Project description:NF-κB is a key regulator of innate and adaptive immunity and is implicated in the pathogenesis of acute kidney injury (AKI). The cell type-specific functions of NF-κB in the kidney are unknown; however, the pathway serves distinct functions in immune and tissue-parenchymal cells. We analyzed tubular epithelial-specific NF-κB signaling in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. NF-κB reporter activity and nuclear localization of phosphorylated NF-κB subunit p65 analyses in mice revealed widespread NF-κB activation in renal tubular epithelia and in interstitial cells following IRI that peaked at 2-3 days after injury. To genetically antagonize tubular epithelial NF-κB activity, we generated mice expressing the human NF-κB super-repressor IκBα∆N in renal proximal, distal, and collecting duct epithelial cells. These mice were protected from IRI-induced AKI, as indicated by improved renal function, reduced tubular apoptosis, and attenuated neutrophil and macrophage infiltration. Tubular NF-κB-dependent gene expression profiles revealed temporally distinct functional gene clusters for apoptosis, chemotaxis, and morphogenesis. Primary proximal tubular cells isolated from IκBα∆N-expressing mice exposed to hypoxia-mimetic agent cobalt chloride were protected from apoptosis and expressed reduced levels of chemokines. Our results indicate that postischemic NF-κB activation in renal-tubular epithelia aggravates tubular injury and exacerbates a maladaptive inflammatory response.
2016-09-17 | GSE87023 | GEO
Project description:The mechanistic target of rapamycin mTORC1 is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTOR inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By utilizing constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in counter-current multiplication and urine concentration. Although mTORC2 partially compensated the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice, and caused pronounced apoptosis, diminished proliferation rates and delayed recovery. These findings identify mTORC1 as an essential regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. Pharmacological inhibition of mTORC1 likely affects tubular homeostasis, and may be particularly deleterious if the kidney is exposed to acute injury. Furthermore, the combined inhibition of mTORC1 and mTORC2 may increase the susceptibility to renal damage.
2014-06-09 | GSE54417 | GEO
Project description:Heart disease remains the leading cause of death globally. Although reperfusion following myocardial ischemia can prevent death by restoring nutrient flow, ischemia/reperfusion injury can cause significant heart damage. The mechanisms that drive ischemia/reperfusion injury are not well understood; currently, few methods can predict the state of the cardiac muscle cell and its metabolic conditions during ischemia. Here, we explored the energetic sustainability of cardiomyocytes, using a model for cellular metabolism to predict the levels of ATP following hypoxia. We modeled glycolytic metabolism with a system of coupled ordinary differential equations describing the individual metabolic reactions within the cardiomyocyte over time. Reduced oxygen levels and ATP consumption rates were simulated to characterize metabolite responses to ischemia. By tracking biochemical species within the cell, our model enables prediction of the cell’s condition up to the moment of reperfusion. The simulations revealed a distinct transition between energetically sustainable and unsustainable ATP concentrations for various energetic demands. Our model illustrates how even low oxygen concentrations allow the cell to perform essential functions. We found that the oxygen level required for a sustainable level of ATP increases roughly linearly with the ATP consumption rate. An extracellular O2 concentration of ~0.007 mM could supply basic energy needs in non-beating cardiomyocytes, suggesting that increased collateral circulation may provide an important source of oxygen to sustain the cardiomyocyte during extended ischemia. Our model provides a time-dependent framework for studying various intervention strategies to change the outcome of reperfusion.
2020-08-25 | BIOMD0000000961 | BioModels
Project description:A subtype of diffuse large B-cell lymphoma (DLBCL), termed activated B-cell-like (ABC) DLBCL, depends on constitutive NF-kB pathway signaling for survival. Small molecule inhibitors of IkB kinase b (IKKb), a key regulator of the NF-kB pathway, kill ABC DLBCL cells and hold promise for the treatment of this lymphoma type. We conducted an RNA interference genetic screen to investigate potential mechanisms of resistance of ABC DLBCL cells to IKKb inhibitors. We screened a library of small hairpin RNAs (shRNAs) targeting 500 protein kinases for shRNAs that would kill an ABC DLBCL cell line in the presence of a small molecule IKKb inhibitor more effectively than in its absence. Two independent shRNAs targeting IKKa synergized with the IKKb inhibitor to kill three different ABC DLBCL cell lines but were not toxic by themselves. Surprisingly, IKKa shRNAs blocked the classical rather than the alternative NF-kB pathway in ABC DLBCL cells, as judged by inhibition of IkBa phosphorylation. IKKa shRNA toxicity was reversed by coexpression of wild type but not kinase inactive forms of IKKa, suggesting that IKKa may directly phosphorylate IkBa under conditions of IKKb inhibition. These results suggest that therapy for ABC DLBCL may be improved by targeting both IKKa and IKKb. Keywords: compound treatment design Gene expression profiling of OCI-Ly3 cells with or without expressing IKKa shRNA in the presence or absence of 12.5 uM IKKb inhibitor for 2 and 3 days. Four samples were analyzed.
2009-06-01 | E-GEOD-11902 | biostudies-arrayexpress
Project description:Cellular senescence is associated with the progression of chronic kidney disease (CKD), and accelerated tubular cell senescence promotes the pathogenesis of renal fibrosis. We established three animal models related to Chronic Kidney Disease, including aristolochic acid nephropathy (AAN), bilateral ischemia/reperfusion injury (BIRI) and unilateral ureter obstruction (UUO). By RNA sequencing analysis in AAN, BIRI and UUO mice, we observed significant changes of senescence and fibrosis related genes.
2024-02-03 | GSE254440 | GEO
Project description:Ischemia/reperfusion injuries is a known complication to hepatic surgery. Ischemic pre- (IPC) and postconditioning (IPO) protects the liver against ischemia/reperfusion-injuries. Expression profiling were performed on liver biopsies seeking to identify molecular mediators of the protective properties. 48 rats were divided into 5 groups; sham (n=8), IRI (n=10), IPC (n=10), IPO (n=10) and IPC+IPO (n=10). All rats except sham rats were subjected to 30 min of total liver ischemia and 30 min of reperfusion before liver biopsies were sampled. In the IPC group, liver ischemia was preceded by 10 min of hepatic ischemia, followed by 10 min of reperfusion. IPO were performed by three cycles of 30 sec of reperfusion and 30 sec of ischemia, applied immediately after the 30 min of total liver ischemia. In the IPC+IPO group the two interventions were combined.
2011-09-30 | E-GEOD-24430 | biostudies-arrayexpress
Project description:Coronary heart disease is the leading cause of death worldwide. After an acute myocardial infarction, early reperfusion reduces infarct size, which correlates with improved clinical outcomes. Paradoxically, reperfusion although relieving ischemia, accelerates apoptosis in injured cardiomyocytes, which has led to the view that myocardial salvage is futile beyond the first few hours of reperfusion. In murine hearts subjected to 90 min of coronary artery occlusion and then 48 h of reperfusion, we show transient activation of intrinsic prosurvival insulin-like growth factor-1 (IGF-1) signaling. In these hearts, acute IGF-1 receptor inhibition decreases the abundance of prosurvival signaling molecules, and markedly activates caspase-3, a potent effector of apoptosis, in infarct border zone cardiomyocytes. We found that mouse mast cell protease-4 (MMCP-4) degraded IGF-1 in vitro by a novel catalytic activity of chymases. In vivo, this degradation, which is triggered by mast cell infiltration into the peri-infarct region and MMCP-4 extravasation, between 48 and 72 h post-ischemia/reperfusion (I/R), attenuates IGF-1 prosurvival signaling. In MMCP-4-deficient mice, while infarct size is not reduced at 24 h post-I/R, at 72 h post-I/R myocardial IGF-1 levels and signaling are increased, resulting in activation of the survival kinases Akt and ERK, inhibition of caspase-3, and reduced myocardial cell death. As a consequence, I/R-mediated loss of viable myocardium, adverse cardiac remodeling and contractile impairment are markedly reduced. Cardiomyocyte survival with consequent myocardial salvage may thus be possible even days after an ischemic insult, making them a novel therapeutic target for delayed cardioprotective therapy. Group 1 is wild type C57Bl6 uninjured hearts. These mice were not undergone any surgery and used as controls. Group 2 are wild type C57Bl6 72 h post-ischemia reperfusion (IR) injury hearts. These mice for subjected to ischemia reperfusion (IR) involving 90 min of left anterior descending coronary artery occlusion followed by reperfusion for 3 days or 72 h.
2015-09-01 | E-GEOD-61592 | biostudies-arrayexpress