scholarly journals Inhibition of Endothelial PHD2 Suppresses Post-Ischemic Kidney Inflammation through Hypoxia-Inducible Factor-1

2020 ◽  
Vol 31 (3) ◽  
pp. 501-516 ◽  
Author(s):  
Ganeshkumar Rajendran ◽  
Michael P. Schonfeld ◽  
Ratnakar Tiwari ◽  
Shengping Huang ◽  
Rafael Torosyan ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Molecular Mechanisms ◽  
Oxygen Sensor ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hypoxia Inducible Factor ◽  
Inflammatory Cells ◽  
Renal Ischemia ◽  
Renal Ischemia Reperfusion Injury

BackgroundProlyl-4-hydroxylase domain-containing proteins 1–3 (PHD1 to PHD3) regulate the activity of the hypoxia-inducible factors (HIFs) HIF-1 and HIF-2, transcription factors that are key regulators of hypoxic vascular responses. We previously reported that deficiency of endothelial HIF-2 exacerbated renal ischemia-reperfusion injury, whereas inactivation of endothelial PHD2, the main oxygen sensor, provided renoprotection. Nevertheless, the molecular mechanisms by which endothelial PHD2 dictates AKI outcomes remain undefined.MethodsTo investigate the function of the endothelial PHD2/HIF axis in ischemic AKI, we examined the effects of endothelial-specific ablation of PHD2 in a mouse model of renal ischemia-reperfusion injury. We also interrogated the contribution of each HIF isoform by concurrent endothelial deletion of both PHD2 and HIF-1 or both PHD2 and HIF-2.ResultsEndothelial deletion of Phd2 preserved kidney function and limited transition to CKD. Mechanistically, we found that endothelial Phd2 ablation protected against renal ischemia-reperfusion injury by suppressing the expression of proinflammatory genes and recruitment of inflammatory cells in a manner that was dependent on HIF-1 but not HIF-2. Persistence of renoprotective responses after acute inducible endothelial-specific loss of Phd2 in adult mice ruled out a requirement for PHD2 signaling in hematopoietic cells. Although Phd2 inhibition was not sufficient to induce detectable HIF activity in the kidney endothelium, in vitro experiments implicated a humoral factor in the anti-inflammatory effects generated by endothelial PHD2/HIF-1 signaling.ConclusionsOur findings suggest that activation of endothelial HIF-1 signaling through PHD2 inhibition may offer a novel therapeutic approach against ischemic AKI.

scholarly journals Overexpression of SP1 restores autophagy to alleviate acute renal injury induced by ischemia-reperfusion through the miR-205/PTEN/Akt pathway

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Chong Huang ◽  
Yan Chen ◽  
Bin Lai ◽  
Yan-Xia Chen ◽  
Cheng-Yun Xu ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Cell Apoptosis ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Akt Pathway ◽  
Acute Renal Injury ◽  
Injury Model ◽  
Renal Ischemia Reperfusion Injury

Abstract Background Acute kidney injury (AKI) is a major kidney disease with poor clinical outcome. SP1, a well-known transcription factor, plays a critical role in AKI and subsequent kidney repair through the regulation of various cell biologic processes. However, the underlying mechanism of SP1 in these pathological processes remain largely unknown. Methods An in vitro HK-2 cells with anoxia-reoxygenation injury model (In vitro simulated ischemic injury disease) and an in vivo rat renal ischemia-reperfusion injury model were used in this study. The expression levels of SP1, miR-205 and PTEN were detected by RT-qPCR, and the protein expression levels of SP1, p62, PTEN, AKT, p-AKT, LC3II, LC3I and Beclin-1 were assayed by western blot. Cell proliferation was assessed by MTT assay, and the cell apoptosis was detected by flow cytometry. The secretions of IL-6 and TNF-α were detected by ELISA. The targeted relationship between miR-205 and PTEN was confirmed by dual luciferase report assay. The expression and positioning of LC-3 were observed by immunofluorescence staining. TUNEL staining was used to detect cell apoptosis and immunohistochemical analysis was used to evaluate the expression of SP1 in renal tissue after ischemia-reperfusion injury in rats. Results The expression of PTEN was upregulated while SP1 and miR-205 were downregulated in renal ischemia-reperfusion injury. Overexpression of SP1 protected renal tubule cell against injury induced by ischemia-reperfusion via miR-205/PTEN/Akt pathway mediated autophagy. Overexpression of SP1 attenuated renal ischemia-reperfusion injury in rats. Conclusions SP1 overexpression restored autophagy to alleviate acute renal injury induced by ischemia-reperfusion through the miR-205/PTEN/Akt pathway.

scholarly journals Dexmedetomidine Preconditioning Protects Rats from Renal Ischemia–Reperfusion Injury Accompanied with Biphasic Changes of Nuclear Factor-Kappa B Signaling

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Naren Bao ◽  
Bing Tang ◽  
Junke Wang
Keyword(s):  
Reperfusion Injury ◽  
Nuclear Factor Kappa B ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Nuclear Factor ◽  
Nuclear Factor Kappa ◽  
Renal Ischemia Reperfusion Injury ◽  
Anti Inflammatory

Acute kidney injury (AKI) is one of the most common and troublesome perioperative complications. Dexmedetomidine (DEX) is a potent α2-adrenoceptor (α2-AR) agonist with anti-inflammatory and renoprotective effects. In this study, a rat renal ischemia–reperfusion injury (IRI) model was induced. At 24 h after reperfusion, the IRI-induced damage and the renoprotection of DEX preconditioning were confirmed both biochemically and histologically. Changes in nuclear factor-kappa B (NF-κB), as well as its downstream anti-inflammatory factor A20 and proinflammatory factor tumor necrosis factor-α (TNF-α), were detected. Atipamezole, a nonselective antagonist, was then added 5 min before the administration of DEX to further analyze DEX’s effects on NF-κB, and another anti-inflammatory medicine, methylprednisolone, was used in comparison with DEX, to further analyze DEX’s effects on NF-κB. Different concentrations of DEX (0 nM, 0.1 nM, 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM) were applied to preincubated human renal tubular epithelial cell line (HK-2) cells in vitro. After anoxia and reoxygenation, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay and enzyme-linked immunosorbent assay (ELISA) were performed to evaluate the levels of NF-κB downstream anti-inflammatory cytokines. The results showed that, unlike methylprednisolone, DEX preconditioning led to a time-dependent biphasic change (first activation then inhibition) of NF-κB in the rat renal IRI models that were given 25 μg/kg i.p. It was accompanied by a similarly biphasic change of TNF-α and an early and persistent upregulation of A20. In vitro, DEX’s cellular protection showed a concentration-dependent biphasic change which was protective within the range of 0 to 100 nM but became opposite when concentrations are greater than 1 μM. The changes in the A20 and NF-κB messenger RNA (mRNA) levels were consistent with the renoprotective ability of DEX. In other words, DEX preconditioning protected the rats from renal IRI via regulation biphasic change of NF-κB signaling.

scholarly journals Indoleamine 2,3-dioxygenase expression promotes renal ischemia-reperfusion injury

2008 ◽  
Vol 295 (1) ◽  
pp. F226-F234 ◽  
Author(s):  
Kanishka Mohib ◽  
Shuang Wang ◽  
Qiunong Guan ◽  
Andrew L. Mellor ◽  
Hongtao Sun ◽  
...  
Keyword(s):  
Serum Creatinine ◽  
Reperfusion Injury ◽  
Renal Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Indoleamine 2,3 Dioxygenase ◽  
Renal Ischemia Reperfusion Injury

Indoleamine 2,3-dioxygenase (IDO) catabolizes tryptophan to N-formyl kynurenine and has a proapoptotic role in renal tubular epithelial cells (TEC) in response to IFN-γ and TNF-α in vitro. TEC produce abundant amounts of IDO in vitro in response to inflammation but a pathological role for IDO in renal injury remains unknown. We investigated the role of IDO in a mouse model of renal ischemia-reperfusion injury (IRI). IRI was induced by clamping the renal pedicle of C57BL/6 mice for 45 min at 32°C. Here, we demonstrate upregulation of IDO in renal tissue at 2 h after reperfusion which reached maximal levels at 24 h. Inhibition of IDO following IRI prevented the increase in serum creatinine observed in vehicle-treated mice (86.4 ± 25 μmol/l, n = 11) compared with mice treated with 1-methyl-d-tryptophan, a specific inhibitor of IDO (33.7 ± 8.7 μmol/l, n = 10, P = 0.031). The role of IDO in renal IRI was further supported by results in IDO-KO mice which maintained normal serum creatinine levels (32.5 ± 2.0 μmol/l, n = 6) following IRI compared with wild-type mice (123 ± 30 μmol/l, n = 9, P = 0.008). Our data suggest that attenuation of IDO expression within the kidney may represent a novel strategy to reduce renal injury as a result of ischemia reperfusion.

scholarly journals Blocking neutrophil integrin activation prevents ischemia–reperfusion injury

2015 ◽  
Vol 212 (8) ◽  
pp. 1267-1281 ◽  
Author(s):  
Tadayuki Yago ◽  
Brian G. Petrich ◽  
Nan Zhang ◽  
Zhenghui Liu ◽  
Bojing Shao ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Integrin Activation ◽  
Β2 Integrin ◽  
Renal Ischemia Reperfusion Injury ◽  
Slow Rolling

Neutrophil recruitment, mediated by β2 integrins, combats pyogenic infections but also plays a key role in ischemia–reperfusion injury and other inflammatory disorders. Talin induces allosteric rearrangements in integrins that increase affinity for ligands (activation). Talin also links integrins to actin and other proteins that enable formation of adhesions. Structural studies have identified a talin1 mutant (L325R) that perturbs activation without impairing talin’s capacity to link integrins to actin and other proteins. Here, we found that mice engineered to express only talin1(L325R) in myeloid cells were protected from renal ischemia–reperfusion injury. Dissection of neutrophil function in vitro and in vivo revealed that talin1(L325R) neutrophils had markedly impaired chemokine-induced, β2 integrin–mediated arrest, spreading, and migration. Surprisingly, talin1(L325R) neutrophils exhibited normal selectin-induced, β2 integrin–mediated slow rolling, in sharp contrast to the defective slow rolling of neutrophils lacking talin1 or expressing a talin1 mutant (W359A) that blocks talin interaction with integrins. These studies reveal the importance of talin-mediated activation of integrins for renal ischemia–reperfusion injury. They further show that neutrophil arrest requires talin recruitment to and activation of integrins. However, although neutrophil slow rolling requires talin recruitment to integrins, talin-mediated integrin activation is dispensable.

scholarly journals miR-21 Contributes to Xenon-conferred Amelioration of Renal Ischemia–Reperfusion Injury in Mice

2013 ◽  
Vol 119 (3) ◽  
pp. 621-630 ◽  
Author(s):  
Ping Jia ◽  
Jie Teng ◽  
Jianzhou Zou ◽  
Yi Fang ◽  
Xiaoyan Zhang ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hypoxia Inducible Factor ◽  
Renal Ischemia ◽  
Locked Nucleic Acid ◽  
Hypoxia Inducible Factor 1Α ◽  
Renal Ischemia Reperfusion Injury

Abstract Background: MicroRNAs participate in the regulation of numerous physiological and disease processes. The in vivo role of microRNAs in anesthetics-conferred organoprotection is unknown. Methods: Mice were exposed for 2 h to either 70% xenon, or 70% nitrogen, 24 h before the induction of renal ischemia-reperfusion injury. The role of microRNA, miR-21, in renal protection conferred by the delayed xenon preconditioning was examined using in vivo knockdown of miR-21 and analysis of miR-21 target pathways. Results: Xenon preconditioning provided morphologic and functional protection against renal ischemia-reperfusion injury (n = 6), characterized by attenuation of renal tubular damage, apoptosis, and oxidative stress. Xenon preconditioning significantly increased the expression of miR-21 in the mouse kidney. A locked nucleic acid-modified anti–miR-21, given before xenon preconditioning, knocked down miR-21 effectively, and exacerbated subsequent renal ischemia-reperfusion injury. Mice treated with anti–miR-21 and ischemia-reperfusion injury showed significantly higher serum creatinine than antiscrambled oligonucleotides-treated mice, 24 h after ischemia-reperfusion (1.37 ± 0.28 vs. 0.81 ± 0.14 mg/dl; n = 5; P < 0.05). Knockdown of miR-21 induced significant up-regulation of programmed cell death protein 4 and phosphatase and tensin homolog deleted on chromosome 10, two proapoptotic target effectors of miR-21, and resulted in significant down-regulation of phosphorylated protein kinase B and increased tubular cell apoptosis. In addition, xenon preconditioning up-regulated hypoxia-inducible factor-1α and its downstream effector vascular endothelial growth factor in a time-dependent manner. Knockdown of miR-21 resulted in a significant decrease of hypoxia-inducible factor-1α. Conclusions: These results indicate that miR-21 contributes to the renoprotective effect of xenon preconditioning.

Renal ischemia/reperfusion injury: An insight on in vitro and in vivo models

Life Sciences ◽  
2020 ◽  
Vol 256 ◽  
pp. 117860 ◽  
Author(s):  
Niharika Shiva ◽  
Nisha Sharma ◽  
Yogesh A. Kulkarni ◽  
Shrikant R. Mulay ◽  
Anil Bhanudas Gaikwad
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
In Vivo Models ◽  
Renal Ischemia Reperfusion Injury

scholarly journals Deficiency of IKKα in Macrophages Mitigates Fibrosis Progression in the Kidney after Renal Ischemia-Reperfusion Injury

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Feng Zhang ◽  
Li Fan ◽  
Hao Zhang ◽  
Wen-juan Huang ◽  
Dong Sun ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Macrophage Polarization ◽  
Renal Ischemia ◽  
Inflammatory Factors ◽  
Iri Model ◽  
Iκb Kinase ◽  
Renal Ischemia Reperfusion Injury

Aims. Acute kidney injury (AKI) can lead to chronic kidney disease (CKD), and macrophages play a key role in this process. The aim of this study was to discover the role of IκB kinase α (IKKα) in macrophages in the process of AKI-to-CKD transition. Main Methods. We crossed lyz2-Cre mice with IKKα-floxed mice to generate mice with IKKα ablation in macrophages (Mac IKKα-/-). A mouse renal ischemia/reperfusion injury (IRI) model was induced by clamping the renal artery for 45 minutes. Treated mice were evaluated for blood biochemistry, tissue histopathology, and fibrosis markers. Macrophages were isolated from the peritoneal cavity for coculturing with tubular epithelial cells (TECs) and flow cytometry analysis. Key Findings. We found that fibrosis and kidney function loss after IRI were significantly alleviated in Mac IKKα-/- mice compared with wild-type (WT) mice. The expression of fibrosis markers and the infiltration of M2 macrophages were decreased in the kidneys of Mac IKKα-/- mice after IRI. The in vitro experiment showed that the IRI TECs cocultured with IKKα-/- macrophages (KO MΦs) downregulated the fibrosis markers accompanied by a downregulation of Wnt/β-catenin signaling. Significance. These data support the hypothesis that IKKα is involved in mediating macrophage polarization and increasing the expression of fibrosis-promoting inflammatory factors in macrophages. Therefore, knockdown of IKKα in macrophages may be a potential method that can be used to alleviate the AKI-to-CKD transition after IRI.

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