Project description:Acute kidney injury (AKI) represents a syndrome seldom characterized by a single, distinct pathophysiological cause. Rhabdomyolysis-induced acute kidney injury (RIAKI) constitutes roughly 15% of AKI cases, yet its underlying pathophysiology remains poorly understood. Using a murine model of RIAKI induced by muscular glycerol injection, we aimed to analyse transcriptomic alterations by RNAseq.
Project description:Rhabdomyolysis is a severe condition caused by skeletal muscle damage, leading to acute kidney injury (AKI). We demonstrate that complement has a direct pathogenic role in rhabdomyolysis-induced AKI. Deposition of C3d in the tubules of patients and mice correlated with rhabdomyolysis-induced AKI. Moreover, C3-defiient mice with rhabdomyolysis had preserved renal function. Mechanistically, C3-deficiency attenuated strongly inflammatory and apoptotic components of the renal transcriptome, perturbed by rhabdomyolysis. Complement was activated intrarenal by the lectin pathway via collectin-11. It proceeded in a C4-bypass manner and was amplified by heme-activated alternative pathway. Therefore, complement and heme are promising therapeutic targets for rhabdomyolysis-induced AKI.
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:In order to reveal the molecular physiological damage mechanism of kidney induced by oxalic acid, single cell sequencing was performed on the kidney of mice with control group and oxalic acid induced acute kidney injury.
Project description:Cisplatin-induced acute kidney injury (AKI) is one of the most common and severe side effects and can prevent the use of this important agent. Unfortunately, preventive or therapeutic tools to address cisplatin-induced AKI are lacking. Interestingly, in the last decades a row of preconditioning strategies that employ the activation of cellular stress resistance pathways have been shown to be promising approaches to protect from organ injury in rodent models. Here, we characterized both the protective potential and the underlying molecular patterns of two strategies – caloric restriction and hypoxic preconditioning – in mice treated with cisplatin.
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:Vancomycin is commonly used as a first line empiric therapy for gram positive organisms such as resistant Staphylococcus species. Vancomycin-induced acute kidney injury (V-AKI) has been reported in up to 43% of patients, especially in those targeting higher trough concentrations. The mechanism of injury in humans remains not well understood with recent evidence pointing to cast nephropathy. In this study, we investigate the protein contents of urinary exosomes in patients with VAN-AKI to further elucidate mechanisms of injury.