scholarly journals Dietary Modification Alters the Intrarenal Immunologic Micromilieu and Susceptibility to Ischemic Acute Kidney Injury

2021 ◽  
Vol 12 ◽  
Author(s):  
Junseok Jeon ◽  
Kyungho Lee ◽  
Kyeong Eun Yang ◽  
Jung Eun Lee ◽  
Ghee Young Kwon ◽  
...  

The versatility of the intrarenal immunologic micromilieu through dietary modification and the subsequent effects on susceptibility to ischemic acute kidney injury (AKI) are unclear. We investigated the effects of high-salt (HS) or high-fat (HF) diet on intrarenal immunologic micromilieu and development of ischemic AKI using murine ischemic AKI and human kidney-2 (HK-2) cell hypoxia models. Four different diet regimens [control, HF, HS, and high-fat diet with high-salt (HF+HS)] were provided individually to groups of 9-week-old male C57BL/6 mice for 1 or 6 weeks. After a bilateral ischemia-reperfusion injury (BIRI) operation, mice were sacrificed on day 2 and renal injury was assessed with intrarenal leukocyte infiltration. Human kidney-2 cells were treated with NaCl or lipids. The HF diet increased body weight and total cholesterol, whereas the HF+HS did not. Although the HF or HS diet did not change total leukocyte infiltration at 6 weeks, the HF diet and HF+HS diet increased intrarenal CD8 T cells. Plasma cells increased in the HF and HS diet groups. The expression of proinflammatory cytokines including TNF-α, IFN-γ, MCP-1, and RANTES was increased by the HF or HS diet, and intrarenal VEGF decreased in the HS and HF+HS diet groups at 6 weeks. Deterioration of renal function following BIRI tended to be aggravated by the HF or HS diet. High NaCl concentration suppressed proliferation and enhanced expression of TLR-2 in hypoxic HK-2 cells. The HF or HS diet can enhance susceptibility to ischemic AKI by inducing proinflammatory changes to the intrarenal immunologic micromilieu.

2017 ◽  
Vol 37 (22) ◽  
Author(s):  
Lei Yu ◽  
Takashi Moriguchi ◽  
Hiroshi Kaneko ◽  
Makiko Hayashi ◽  
Atsushi Hasegawa ◽  
...  

ABSTRACT Acute kidney injury (AKI) is a leading cause of chronic kidney disease. Proximal tubules are considered to be the primary origin of pathogenic inflammatory cytokines in AKI. However, it remains unclear whether other cell types, including collecting duct (CD) cells, participate in inflammatory processes. The transcription factor GATA2 is specifically expressed in CD cells and maintains their cellular identity. To explore the pathophysiological function of GATA2 in AKI, we generated renal tubular cell-specific Gata2 deletion (G2CKO) mice and examined their susceptibility to ischemia reperfusion injury (IRI). Notably, G2CKO mice exhibited less severe kidney damage, with reduced granulomacrophagic infiltration upon IRI. Transcriptome analysis revealed that a series of inflammatory cytokine genes were downregulated in GATA2-deficient CD cells, suggesting that GATA2 induces inflammatory cytokine expression in diseased kidney CD cells. Through high-throughput chemical library screening, we identified a potent GATA inhibitor. The chemical reduces cytokine production in CD cells and protects the mouse kidney from IRI. These results revealed a novel pathological mechanism of renal IRI, namely, that CD cells produce inflammatory cytokines and promote IRI progression. In injured kidney CD cells, GATA2 exerts a proinflammatory function by upregulating inflammatory cytokine gene expression. GATA2 can therefore be considered a therapeutic target for AKI.


Author(s):  
Razvan Andrei CODEA ◽  
Mircea MIRCEAN ◽  
Sidonia Alina BOGDAN ◽  
Andras Laszlo NAGY ◽  
Alexandra BIRIS ◽  
...  

The identification of a suitable prevention method which facilitates limiting the deleterious effects of acute kidney injuries is highly required. In order to identify a proper treatment for acute kidney injuries, a suitable experimental model that replicates the structural, metabolic and inflammatory lesions that occur in the natural acute injured kidney is highly necessary. Intense urinary NAG activity can be found in a variety of renal disease such as toxic nephropathies, ischemic renal injury following cardiac surgery or renal transplantation but also in glomerular disease especially in diabetic nephropathy. Rises in urinary NAG enzyme activity strongly suggests tubular cell damage and support NAG enzyme as a biomarker of renal tubular injury. The aim of this paper is to obtain a stable in vivo acute kidney injury experimental model, in Wistar, rats and to evaluate the urinary activity of N-acetyl-β-D-glucosaminidase (NAG) enzyme, blood levels of urea and creatinine and microstructural renal alterations induced by ischemia/reperfusion injury respectively gentamicin nephrotoxicity. For this purpose we have used a rat experimental model. Adult male Wistar rats weighing 250-300 g were randomly divided into 3 groups with 8 rats in each group. Group 1 served as a model for the renal ischemia/reperfusion injury experiment, group 2 served for toxic kidney injury experimental model and group 3 served as control group. All individuals in both groups 1 and 2 presented marked elevations in blood urea and creatinine at the moment of euthanasia (day 3 for group 1 and day 9 for group 2) compared to the control group where biochemical values remained within normal limits. Urine analysis of both group 1 and 2 showed marked urinary NAG index activity which suggests acute tubular injury, suggestion confirmed by histological evaluation of the renal parenchyma sampled from this subjects


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Julia Wilflingseder ◽  
Michaela Willi ◽  
Hye Kyung Lee ◽  
Hannes Olauson ◽  
Jakub Jankowsky ◽  
...  

Abstract Background and Aims The endogenous repair process of the mammalian kidney allows rapid recovery after acute kidney injury (AKI) through robust proliferation of tubular epithelial cells. There is currently limited understanding of which transcriptional regulators activate these repair programs and how transcriptional dysregulation leads to maladaptive repair. Here we investigate the existence of enhancer dynamics in the regenerating mouse kidney. Method RNA-seq and ChIP-seq (H3K27ac, H3K4m3, BRD4, POL2 and selected transcription factors) were performed on samples from repairing kidney cortex 2 days after ischemia/reperfusion injury (IRI) to identify activated genes, transcription factors, enhancer and super-enhancers associated with kidney repair. Further we investigated the role of super-enhancer activation in kidney repair through pharmacological BET inhibition using the small molecule JQ1 in vitro and in acute kidney injury models in vivo. Results Response to kidney injury leads to genome-wide alteration in enhancer repertoire in-vivo. We identified 16,781 enhancer sites (H3K27ac and BRD4 positive, H3K4me3 negative binding) active in SHAM and IRI samples; 6,512 lost and 9,774 gained after IRI. The lost and gained enhancer sites can be annotated to 62% and 63% of down- and up-regulated transcripts at day 2 after kidney injury, respectively. Super-enhancer analysis revealed 164 lost and 216 gained super-enhancer sites at IRI day 2. 385 super-enhancers maintain activity before and after injury. ChIP-seq profiles of selected transcription factors based on motif analysis show specific binding at corresponding enhancer sites. We observed lost enhancer binding of HNF4A and GR mainly at kidney related enhancer elements. In contrast, STAT3 showed increased binding at injury induces enhancer elements. No dynamic was observed for STAT5. Both transcription factor groups show corresponding mRNA changes after injury. Pharmacological inhibition of enhancer and super-enhancer activity by BRD4 inhibition (JQ1: 50mg/kg/day) before IRI leads to suppression of 40% of injury-induced transcripts associated with cell cycle regulation and significantly increased mortality between days 2 and 3 after AKI. Conclusion This is the first demonstration of enhancer and super-enhancer function in the repairing kidney. In addition, our data call attention to potential caveats for use of small molecule inhibitors of BET proteins that are currently being tested in clinical trials in cancer patients who are at risk for AKI. Our analyses of enhancer dynamics after kidney injury in vivo have the potential to identify new targets for therapeutic intervention.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Johanna Störmer ◽  
Faikah Gueler ◽  
Song Rong ◽  
Mi-Sun Jang ◽  
Nelli Shushakova ◽  
...  

Abstract Background and Aims Diclofenac is frequently used for pain control. In a previous study, we showed that already a single oral dose of diclofenac could reduce renal perfusion in healthy individuals. To investigate the influence of oral diclofenac administration on renal inflammation in the setting of pre-existing renal damage, we used a mouse model of subclinical acute kidney injury (AKI) induced by renal ischemia-reperfusion injury (IRI) followed by diclofenac administration. Method Male CD1 mice (7-8 weeks old) underwent unilateral renal pedicle clamping for 15min to induce subclinical AKI. After reperfusion mice received a single oral dose of 100 or 200mg/kg diclofenac via oral gavage. Vehicle treated mice with unilateral IRI served as control. At day 1, mice were placed into metabolic cages to collect urine. Histology was performed on day 1 and 14 for renal morphology. Inflammation and fibrosis were investigated by immunohistochemistry and qPCR. Results Diclofenac treated mice showed reduced urine production. Morphologically, signs of AKI were more pronounced in diclofenac treated kidneys which also showed more Cox-2 positive tubuli in the cortex. On mRNA expression level the pro-inflammatory markers IL-6 and CXCL2, the chemoattractant for neutrophils, were elevated in the diclofenac group. Early upregulation of the pro-fibrotic markers CTGF and PAI-1 was detected already on d1 after IRI in the diclofenac group and tubular atrophy was pronounced after two weeks. Conclusion Already, a single oral dose of diclofenac causes aggravation of renal inflammation and progressive renal fibrosis in the setting of pre-existing subclinical acute kidney injury.


2015 ◽  
Vol 309 (10) ◽  
pp. F852-F863 ◽  
Author(s):  
Sara Hirsch ◽  
Tarek El-Achkar ◽  
Lynn Robbins ◽  
Jeannine Basta ◽  
Monique Heitmeier ◽  
...  

It has been postulated that developmental pathways are reutilized during repair and regeneration after injury, but functional analysis of many genes required for kidney formation has not been performed in the adult organ. Mutations in SALL1 cause Townes-Brocks syndrome (TBS) and nonsyndromic congenital anomalies of the kidney and urinary tract, both of which lead to childhood kidney failure. Sall1 is a transcriptional regulator that is expressed in renal progenitor cells and developing nephrons in the embryo. However, its role in the adult kidney has not been investigated. Using a mouse model of TBS ( Sall1 TBS), we investigated the role of Sall1 in response to acute kidney injury. Our studies revealed that Sall1 is expressed in terminally differentiated renal epithelia, including the S3 segment of the proximal tubule, in the mature kidney. Sall1 TBS mice exhibited significant protection from ischemia-reperfusion injury and aristolochic acid-induced nephrotoxicity. This protection from acute injury is seen despite the presence of slowly progressive chronic kidney disease in Sall1 TBS mice. Mice containing null alleles of Sall1 are not protected from acute kidney injury, indicating that expression of a truncated mutant protein from the Sall1 TBS allele, while causative of congenital anomalies, protects the adult kidney from injury. Our studies further revealed that basal levels of the preconditioning factor heme oxygenase-1 are elevated in Sall1 TBS kidneys, suggesting a mechanism for the relative resistance to injury in this model. Together, these studies establish a functional role for Sall1 in the response of the adult kidney to acute injury.


Biology ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 48 ◽  
Author(s):  
Theodoros Eleftheriadis ◽  
Georgios Pissas ◽  
Georgia Antoniadi ◽  
Vassilios Liakopoulos ◽  
Ioannis Stefanidis

Ischemia–reperfusion injury contributes to the pathogenesis of many diseases, with acute kidney injury included. Hibernating mammals survive prolonged bouts of deep torpor with a dramatic drop in blood pressure, heart, and breathing rates, interspersed with short periods of arousal and, consequently, ischemia–reperfusion injury. Clarifying the differences under warm anoxia or reoxygenation between human cells and cells from a native hibernator may reveal interventions for rendering human cells resistant to ischemia–reperfusion injury. Human and hamster renal proximal tubular epithelial cells (RPTECs) were cultured under warm anoxia or reoxygenation. Mouse RPTECs were used as a phylogenetic control for hamster cells. Cell death was assessed by both cell imaging and lactate dehydrogenase (LDH) release assay, apoptosis by cleaved caspase-3, autophagy by microtubule-associated protein 1-light chain 3 B II (LC3B-II) to LC3B-I ratio, necroptosis by phosphorylated mixed-lineage kinase domain-like pseudokinase, reactive oxygen species (ROS) fluorometrically, and lipid peroxidation, the end-point of ferroptosis, by malondialdehyde. Human cells died after short periods of warm anoxia or reoxygenation, whereas hamster cells were extremely resistant. In human cells, apoptosis contributed to cell death under both anoxia and reoxygenation. Although under reoxygenation, ROS increased in both human and hamster RPTECs, lipid peroxidation-induced cell death was detected only in human cells. Autophagy was observed only in human cells under both conditions. Necroptosis was not detected in any of the evaluated cells. Clarifying the ways that are responsible for hamster RPTECs escaping from apoptosis and lipid peroxidation-induced cell death may reveal interventions for preventing ischemia–reperfusion-induced acute kidney injury in humans.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shataakshi Dube ◽  
Tejasvi Matam ◽  
Jessica Yen ◽  
Henry E. Mang ◽  
Pierre C. Dagher ◽  
...  

STAT3 is a transcriptional regulator that plays an important role in coordinating inflammation and immunity. In addition, there is a growing appreciation of the role STAT3 signaling plays in response to organ injury following diverse insults. Acute kidney injury (AKI) from ischemia-reperfusion injury is a common clinical entity with devastating consequences, and the recognition that endothelial alterations contribute to kidney dysfunction in this setting is of growing interest. Consequently, we used a mouse with a genetic deletion of Stat3 restricted to the endothelium to examine the role of STAT3 signaling in the pathophysiology of ischemic AKI. In a mouse model of ischemic AKI, the loss of endothelial STAT3 signaling significantly exacerbated kidney dysfunction, morphologic injury, and proximal tubular oxidative stress. The increased severity of ischemic AKI was associated with more robust endothelial-leukocyte adhesion and increased tissue accumulation of F4/80+ macrophages. Moreover, important proximal tubular adaptive mechanisms to injury were diminished in association with decreased tissue mRNA levels of the epithelial cell survival cytokine IL-22. In aggregate, these findings suggest that the endothelial STAT3 signaling plays an important role in limiting kidney dysfunction in ischemic AKI and that selective pharmacologic activation of endothelial STAT3 signaling could serve as a potential therapeutic target.


2010 ◽  
Vol 299 (5) ◽  
pp. F1134-F1140 ◽  
Author(s):  
Maarten G. Snoeijs ◽  
Hans Vink ◽  
Niek Voesten ◽  
Maarten H. Christiaans ◽  
Jan-Willem H. Daemen ◽  
...  

Increased understanding of the pathophysiology of ischemic acute kidney injury in renal transplantation may lead to novel therapies that improve early graft function. Therefore, we studied the renal microcirculation in ischemically injured kidneys from donors after cardiac death (DCD) and in living donor kidneys with minimal ischemia. During transplant surgery, peritubular capillaries were visualized by sidestream darkfield imaging. Despite a profound reduction in creatinine clearance, total renovascular resistance of DCD kidneys was similar to that of living donor kidneys. In contrast, renal microvascular perfusion in the early reperfusion period was 42% lower in DCD kidneys compared with living donor kidneys, which was accounted for by smaller blood vessel diameters in DCD kidneys. Furthermore, DCD kidneys were characterized by smaller red blood cell exclusion zones in peritubular capillaries and by greater production of syndecan-1 and heparan sulfate (main constituents of the endothelial glycocalyx) compared with living donor kidneys, providing strong evidence for glycocalyx degradation in these kidneys. We conclude that renal ischemia and reperfusion is associated with reduced capillary blood flow and loss of glycocalyx integrity. These findings form the basis for development of novel interventions to prevent ischemic acute kidney injury.


2018 ◽  
Author(s):  
Pietro E Cippà ◽  
Bo Sun ◽  
Jing Liu ◽  
Liang Chen ◽  
Maarten Naesens ◽  
...  

AbstractOur molecular understanding of clinical conditions progressing from acute organ injury to irreversible dysfunction is limited. We used renal transplantation as a model to characterize the transcriptional response along the transition from acute kidney injury to allograft fibrosis in humans. The integrated analysis of 163 transcriptomes with machine learning techniques identified shared and divergent transcriptional trajectories determining distinct clinical outcomes in a heterogeneous population. The molecular map of renal responses to injury was validated in a mouse ischemia-reperfusion injury model and highlighted early markers of disease progression. This generally applicable approach opens the way for an unbiased analysis of progressive diseases.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jing-Ying Zhao ◽  
Yu-Bin Wu

Endoplasmic reticulum stress (ERS) is strongly associated with acute kidney injury (AKI) to chronic kidney disease (CKD) transition. Huaier extract (HE) protects against kidney injury; albeit, the underlying mechanism is unknown. We hypothesized that HE reduces kidney injury by inhibiting ERS. In this study, using an AKI-CKD mouse model of ischemia-reperfusion injury (IRI), we evaluated the effect of HE on AKI-CKD transition. We also explored the underlying molecular mechanisms in this animal model and in the HK-2 human kidney cell line. The results showed that HE treatment improved the renal function, demonstrated by a significant decrease in serum creatinine levels after IRI. HE appreciably reduced the degree of kidney injury and fibrosis and restored the expression of the microRNA miR-1271 after IRI. Furthermore, HE reduced the expression of ERS markers glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) and inhibited apoptosis in the IRI group. This in vivo effect was supported by in vitro results in which HE inhibited apoptosis and decreased the expression of CHOP and GRP78 induced by ERS. We demonstrated that CHOP is a target of miR-1271. In conclusion, HE reduces kidney injury, probably by inhibiting apoptosis and decreasing the expression of GRP78 and CHOP via miR-1271 upregulation.


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