Project description:The aim of this study was to identify miRNAs that regulate AKI and develop their applications as diagnostic biomarkers and therapeutic agents. First, kidney tissues from two different AKI mouse models, namely, AKI induced by the administration of lipopolysaccharide (LPS) causing sepsis (LPS-AKI mice) and AKI induced by renal ischemia–reperfusion injury (IRI-AKI mice), were exhaustively screened for their changes of miRNA expression compared with that of control mice by microarray analysis.
Project description:The aim of this study was to identify miRNAs that regulate AKI and develop their applications as diagnostic biomarkers and therapeutic agents. First, kidney tissues from two different AKI mouse models, namely, AKI induced by the administration of lipopolysaccharide (LPS) causing sepsis (LPS-AKI mice) and AKI induced by renal ischemia–reperfusion injury (IRI-AKI mice), were exhaustively screened for their changes of miRNA expression compared with that of control mice by microarray analysis.
Project description:Ischemic acute kidney injury (AKI), a complication that frequently occurs in hospital settings, is often associated with hemodynamic compromise, sepsis, cardiac surgery or exposure to nephrotoxicants. AKI is associated with immune cell infiltration into the kidney stroma, which causes acute tubular injury. Here, using a murine renal ischemic-reperfusion injury (IRI) model we show that intercalated cells (ICs) rapidly adopt a pro-inflammatory phenotype post IRI. During the early phase of AKI, we demonstrate that either blocking the pro-inflammatory P2Y14 receptor located on the apical membrane of ICs, or ablation of the gene encoding the P2Y14 receptor in ICs: 1) inhibits IRI-induced chemokine expression increase in ICs; 2) reduces neutrophil and monocyte renal infiltration; 3) reduces the extent of kidney dysfunction; and 4) attenuates proximal tubule (PT) damage. These observations indicate that the P2Y14 receptor participates in the very first inflammatory steps associated with ischemic AKI. In addition, we show that the concentration of the P2Y14 receptor ligand, uridine diphosphate-glucose (UDP-Glc), is higher in urine samples from intensive care unit patients who developed AKI when compared with urine from patients without AKI. In particular, we observed a strong correlation between UDP-Glc concentration and the development of AKI in cardiac surgery patients. Our study identifies the UDP-Glc/P2Y14 receptor axis as a potential target for the prevention and/or attenuation of ischemic-AKI.
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: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.
Project description:Acute kidney disease caused by ischemia-reperfusion (IRI-AKI) is characterized by ectopic inflammation and tubular injury, in which macrophage infiltration and inflammatory activation play a critical pathogenic role. Calycosin is an active flavone from the root of Astragalus membranaceus and shows anti-inflammatory effects in various diseases. In this study, we investigated the renoprotective role of calycosin against IRI-AKI and the underlying mechanism. Our results showed that calycosin treatment reduced the levels of serum creatinine and urea nitrogen along with attenuated tubular necrosis and cast formation in IRI-AKI mice. Calycosin significantly suppressed the activation of NF-κB signaling and the expression of inflammatory mediators IL-1β and TNF-α in IRI-AKI kidneys. In vitro, calycosin inhibited LPS-induced inflammatory activation in RAW 264.7 cells. Interestingly, RNA-seq revealed that calycosin remarkably down-regulated chemotaxis-related pathways in RAW 264.7 cells. Among the differentially expressed genes, Ccl2/MCP-1, a critical chemokine mediating macrophage inflammatory chemotaxis, was down-regulated in both LPS-stimulated RAW 264.7 cells and IRI-AKI kidneys. Consistently, calycosin treatment attenuated macrophage infiltration in the IRI-AKI kidneys. Importantly, in combination with target prediction, molecular docking, and surface plasmon resonance, we showed that calycosin can directly bind to macrophage migration inhibitory factor (MIF). Functionally, calycosin abrogated MIF-stimulated NF-κB signaling activation and Ccl2 expression and MIF-mediated chemotaxis in RAW 264.7 cells without influencing its expression. Collectively, calycosin protects from IRI-AKI by suppressing MIF-mediated macrophage inflammatory chemotaxis. Calycosin could be a promising candidate medicine for clinical treatment of IRI-AKI.
Project description:RNA-seq analysis of kidney samples from mice after ischemia-reperfusion injury (IRI) identified 1,109 genes with altered expression between mild (20 minutes) and severe (35 minutes) IRI groups. Among these, 974 genes were upregulated and 135 were downregulated in the severe group.
Project description:Retinoic acid (RA) signaling is activted in proximal tubular epithelial cells (PTECs) after acute kidney injury (AKI). In these studies we evaluated the functional role of this by inducing ischemia reperfusion-induced AKI (IRI-AKI) in mice after inhibiting RA signaling in PTECs genetically. Here we evaluated the effects of this on the activation of renal mononuclear cells (MNCs) by evaluating RNA expression in CD11B+ cells isolated from kidneys after IRI-AKI. Compared with control mice, there was a reducion in expression of inflammatory marker gene expression 3 days after IRI-AKI in mice with inhibition of RAR signaling in PTECs. These findings suggest a mechanism by which inhibition of RAR signaling in PTECs is protective against AKI.
Project description:We analyzed differences in IRI kidneys between WT and Keap1 KD mice (= Nrf2-activated mice). To identify Nrf2-target genes or metabolic genes in kidneys, we examined the mRNA expression profile both in normal (uninjured) and IRI kidneys (at day1 after unilateral IRI) from mice We performed microarray analyses using 1) Injured kidneys at day 1 after unilateral IRI, and 2) intact kidneys from mice which did not undergo UIRI. Samples were harvested from Keap1 KD mice and WT mice, n = 2 each,