Project description:The precise physiological mechanisms of cardio-renal syndrome are yet to be elucidated. In order to investigate the molecular basis of cardio-renal syndrome, we established a mouse model for cardio-renal syndrome by the combination of abdominal aortic banding and uninephrectomy. Renal function of the cardio-renal syndrome mice was synergistically decreased compared with that of mice that underwent uninephrectomy alone. To investigate the molecules involved in the deterioration renal function in the AbNx mice, we conducted comprehensive gene expression analysis using DNA array by comparing the molecules expressed in the remained kidney of AbNx mice with those of Nx mice.
Project description:The precise physiological mechanisms of cardio-renal syndrome are yet to be elucidated. In order to investigate the molecular basis of cardio-renal syndrome, we established a mouse model for cardio-renal syndrome by the combination of abdominal aortic banding and uninephrectomy. Renal function of the cardio-renal syndrome mice was synergistically decreased compared with that of mice that underwent uninephrectomy alone. To investigate the molecules involved in the deterioration renal function in the AbNx mice, we conducted comprehensive gene expression analysis using DNA array by comparing the molecules expressed in the remained kidney of AbNx mice with those of Nx mice. We conducted abdominal aorta banding or sham operation at 0 week, then We conducted uninephrectomy or sham operation at 2 week. We removed these kidney 6week after the uninephrectomy. These RNA samples were purified from the homogenized kidneys.
Project description:The endocytic receptor megalin constitutes the main pathway for clearance of plasma proteins from the glomerular filtrate in the proximal tubules. However, little is know about the mechanisms that control receptor activity. A widely discussed hypothesis states that the intracellular domain (ICD) of megalin, released upon ligand binding, acts as a transcription regulator to suppress receptor expression - a mechanism proposed to safeguard the proximal tubules from protein overload. Here, we have put this hypothesis to the test by generating a mouse model co-expressing the soluble ICD and the full-length receptor. Despite pronounced expression in the proximal tubules, the ICD failed to exert any effects on renal proximal tubular function such as megalin expression, protein retrieval, or renal gene transcription. Thus, our data argue that the ICD does not play a role in regulation of megalin activity in vivo in the proximal tubules. We used microarrays to compare gene expression profile in adult kidney from a new mouse model expressing the intracellular domain of megalin with wildtype. 10 week old mice were collected for RNA extraction and hybridization on Affymetrix microarrays. Three individuals for each genotype were analyzed comparing heterozygous animals for the intracellular domain of megalin with littermates controls.
Project description:The endocytic receptor megalin constitutes the main pathway for clearance of plasma proteins from the glomerular filtrate in the proximal tubules. However, little is know about the mechanisms that control receptor activity. A widely discussed hypothesis states that the intracellular domain (ICD) of megalin, released upon ligand binding, acts as a transcription regulator to suppress receptor expression - a mechanism proposed to safeguard the proximal tubules from protein overload. Here, we have put this hypothesis to the test by generating a mouse model co-expressing the soluble ICD and the full-length receptor. Despite pronounced expression in the proximal tubules, the ICD failed to exert any effects on renal proximal tubular function such as megalin expression, protein retrieval, or renal gene transcription. Thus, our data argue that the ICD does not play a role in regulation of megalin activity in vivo in the proximal tubules. We used microarrays to compare gene expression profile in adult kidney from a new mouse model expressing the intracellular domain of megalin with wildtype.
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:Shiga toxin type 2 (Stx2) from Escherichia coli is thought to be a main factor to casue renal dysfunction in Enterohemorrhagic E. coli (EHEC) infection. The renal dysfunction caused by the proximal tubular defects can be detected in the earlier EHEC infection. However, the precise information of gene expression from proximal tubular epithelial cells has yet to be clarified. We performed microarray experiments using Stx2-injected mouse kidney and Stx2-treated human renal proximal tubular epithelial cells (RPTEC), and extracted common genes that were differentially expressed.
Project description:Shiga toxin type 2 (Stx2) from Escherichia coli is thought to be a main factor to casue renal dysfunction in Enterohemorrhagic E. coli (EHEC) infection. The renal dysfunction caused by the proximal tubular defects can be detected in the earlier EHEC infection. However, the precise information of gene expression from proximal tubular epithelial cells has yet to be clarified. We performed microarray experiments using Stx2-injected mouse kidney and Stx2-treated human renal proximal tubular epithelial cells (RPTEC), and extracted common genes that were differentially expressed.
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:To understand the transcription regulation of renal tubular epithelial cells under stimuli, here we investigated transcriptome, chromatin accessibility and their dynamics through RNA-seq and ATAC-seq under the three types of treatments. We identified genome-wide functional regions which coordinated transcription regulation in human renal proximal tubule epithelial cells (HK2). Our results provide a cell type-specific landscape of chromatin dynamics under stimuli and discovered an important TF in renal tubular epithelial cells that mediated genomic response to different injury stimuli.
Project description:The study used a clinically relevant mouse model of chronic aristolochic acid nephropathy (AAN) to investigate the responses of proximal tubular cells during kidney fibrosis by single-nucleus RNA sequencing. The experiment involved 4 mice with AAN induced chronic renal fibrosis and 4 naive controls.