Transcriptome profile of a murine renal bilateral ischemia reperfusion model 2 hours to 12 months post injury
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ABSTRACT: Acute kidney injury (AKI) is associated with an increased risk of chronic kidney disease (CKD). To extend our understanding of renal repair, and its limits, we performed a detailed molecular characterization of a murine ischemia reperfusion injury (IRI) model for 12 months post injury. RNA-seq analysis highlights a cascade of temporal specific gene expression patterns related to tubular injury/repair, fibrosis, innate and adaptive immunity.
Project description:To better understand the pathogenesis of AKI-to-CKD transition and specifically the mechanism of kidney atrophy, we compared the kidney response to an identical time of ischemic injury between mice subjected to unilateral ischemia/reperfusion (U-IRI) to induce atrophy and those subjected to unilateral IRI with contralateral nephrectomy (IRI/CL-NX) to induce adaptive repair. We performed single cell RNA-sequencing (scRNA-seq) analyses on day 14 after injury to identify major cell types in the kidney and the differential transcriptional response between the models in each cell type.
Project description:Men are more prone to acute kidney injury (AKI) and chronic kidney disease (CKD), progressingto end-stage renal disease (ESRD) than women. Severity and capacity to regenerate after AKI are important determinants of CKD progression, and of patient morbidity and mortality in the hospital setting. To determine sex diferences during injury and recovery we have generated a female and male renal ischemia/reperfusion injury (IRI) pig model, which represents a major cause of AKI. This study was conducted using farm pigs, hybrids between Large White and Landrace. Five females and five males of four months old, free of specifc pathogens, between 30 and 40 kg of weight were included in this study. This age range was chosen due to the sexual maturity of the animal, allowing hormone efects. Using microarray assays, global transcriptomic analyses of kidney biopsies from this IRI pig model was conducted and revealed a sexual dimorphism in the temporal regulation of genes and pathways relevant for kidney injury and repair. Overall, this study constitutes an extensive characterization of the time and sex diferences occurring during renal IRI and recovery at gene expression level.
Project description:Chronic kidney disease (CKD) is a significant global health burden. Acute kidney injury (AKI) is a risk factor for progression to CKD. Recent studies have linked a failure in proximal tubule repair as a potential contributing factor to CKD in mouse and human studies. Failed repair proximal tubule cells (FR-PTCs), initially present at the site of maximal sensitivity to ischemia reperfusion injury and spreading to more cortical regions over time, adopt a senescence-associated secretory phenotype (SASP) linked to activation of the NF-kB pathway. Several transcriptional regulatory factors mediate NF-kB pathway action. Of these, Nfkb1 is prominent within FR-PTCs and chromatin studies predict Nfkb1 interactions with pathology-associated gene targets. To examine the role of NF-kB in nephron injury outcomes, we removed Nfkb1 activity within the nephron lineage of the mouse kidney and examined the kidney’s response to bilateral ischemia reperfusion injury (Bi-IRI).
Project description:Incomplete repair after acute kidney injury (AKI) is associated with progressive loss of tubular cell function and development of chronic kidney disease (CKD). Here, we compared the kidney single-cell transcriptomes from the mice subjected to either unilateral ischemia-reperfusion kidney injury with contralateral nephrectomy (IRI/CL-NX, in which tubule repair predominates) or unilateral IRI with contralateral kidney intact (U-IRI, in which fibrosis and atrophy predominates) to investigate the mechanism(s) underlying transition to CKD following AKI.
Project description:Recently, acute kidney injury (AKI) is thought to develop a predisposition toward chronic kidney disease. But the detailed mechanism of the disease progression after AKI is unknown. We made two ischemia-reperfusion injury (IRI) mice models, repaired kidney model and atrophic kidney model, and studied the mechanism that kidney after IRI became atrophy. We found that the atrophy kidney model had two peaks of apoptosis 3 and 14 days after IRI, whereas the repaired kidney model had only one apoptosis peak 3 days after IRI. We showed that the second apoptosis is responsible for the kidney atrophy. Moreover, apoptotic ligands, TNFα and FasL were upregulated at the same time of two apoptosis peaks on the atrophic kidney, and blockade of them before IRI prevented kidney from falling into atrophy. Surprisingly, inhibition of the second apoptosis by anti-TNFα antibody protected from renal atrophy. We propose that apoptosis might play a major role in AKI progression and blockade of TNFα after IRI will be a new therapeutic approach for AKI.
Project description:Ischemia-reperfusion injury (IRI) is a well-known model for acute kidney injury (AKI).
We applied proteomic analysis to detect membrane proteins from IRI mouse kidneys. The analysis set are composed of negative control (sham operation), samples of 4-hour after IRI, and samples of 8-hour IRI.
Project description:Acute kidney injury (AKI) represents a common complication in critically ill patients that is associated with an increased morbidity and mortality. Currently, no effective treatment options are available. Here, we show that glutamine significantly attenuates leukocyte recruitment and inflammatory signaling in human and murine tubular epithelial cells (TECs). In a murine AKI model induced by ischemia-reperfusion-injury (IRI) we show that glutamine causes transcriptomic and proteomic reprogramming in renal TECs and neutrophils, resulting in decreased epithelial apoptosis, neutrophil recruitment and improved mitochondrial functionality and respiration provoked by an ameliorated oxidative phosphorylation. We identify the proteins glutamine gamma glutamyltransferase 2 (Tgm2) and apoptosis signal-regulating kinase (Ask1) as the major targets of glutamine in apoptotic signaling. Increased Tgm2 expression and reduced Ask1 activation result in decreased JNK activation leading to a diminished mitochondrial intrinsic apoptosis in kidneys upon IRI-induced AKI and under hypoxia or following TNFα-treatment of TECs. Consequently, glutamine administration attenuated kidney injury in vivo during AKI progression as well as TEC viability in vitro under inflammatory and hypoxic conditions.
Project description:RIR leads to ischemic acute kidney injury (AKI). Women below the age of menopause have a lower incidence of AKI. It is bellieved that estrogens are protective. Many genes were shown to be altered in female wild-type mice subjected to IRI.
Project description:Preconditioning strategies like caloric restriction (CR) and hypoxic preconditioning (HP) show remarkable protective effects in animal models of acute kidney injury (AKI). Since the underlying molecular effects are still not fully understood we performed an experiment directly comparing CR and HP in a murine model of ischemia-reperfusion injury (IRI) of the kidney. 8 to 12-week-old, male C57BL6/J mice were either put to 4 weeks of caloric restriction (70% of normal food intake) or placed in a hypoxic chamber (8%O2) for 3 consecutive days prior to IRI. Whole kidneys were used for transcriptional analysis (RNAseq) before and after ischemia-reperfusion injury to look for common effects of both modes of preconditioning.
Project description:tRNA-derived fragments (tRFs) play critical roles in cellular process, and we have previously reported that tRFs are involved in ischemia reperfusion injury induced acute kidney injury (IRI-AKI). However, the precise involvement of tRFs in IRI-AKI remains obscure. This study aims to elucidate the impact of tRF-Val-TAC-004 (tRF-Val) on IRI-AKI and uncover the underlying mechanisms. Our observations reveal a significant downregulation of tRF-Val in IRI-AKI mice and its overexpression mitigated renal dysfunction, morphological damage, and apoptosis in IRI-AKI mice, while its inhibition exacerbated these effects. Similar outcomes were replicated in CoCl2-treated BUMPT cells upon transfection with tRF-Val mimic or inhibitor. Mechanistically, dual-luciferase reporter assay and AGO-RIP qPCR analyses demonstrated that tRF-Val suppresses Apaf1 expression by targeting the 3’-UTR of Apaf1 mRNA. Furthermore, the protective efficacy of tRF-Val was notably weakened by Apaf1-overexpressing plasmids. In summary, these novel findings unveil the protective role of tRF-Val against IRI-AKI through inhibition of Apaf1-mediated apoptosis.