MicroRNA-34a Suppresses Autophagy in Tubular Epithelial Cells in Acute Kidney Injury

2015 ◽  
Vol 42 (2) ◽  
pp. 168-175 ◽  
Author(s):  
Xiu-Juan Liu ◽  
Quan Hong ◽  
Zhen Wang ◽  
Yan-Yan Yu ◽  
Xin Zou ◽  
...  

Background: Acute kidney injury (AKI) is traditionally described as a condition leading to rapid damage to kidney function, eventually becoming a significant healthcare concern with a high mortality rate. Autophagy deficiency in the tubular epithelial cells is the main cause of AKI; however, the underlying molecular mechanism remains to be defined. MicroRNAs (miRNAs) are related to autophagy in many diseases. This study was aimed at investigating the relationship between miRNA expression and autophagic activity in the pathogenesis of AKI. Methods: A mouse model of AKI was produced by ischemia reperfusion (I/R). The expressions of microRNA-34a (miR-34a) and the autophagy-related protein LC3 II/I and p62 were determined in renal tissues and the tubular epithelial cells (RTECs). Moreover, the autophagic activity was investigated after miR-34a overexpression and inhibition. Additionally, the effect of miR-34a on its target gene in regulating autophagic activity in RTECs was also investigated. Results: I/R suppressed the autophagic activity and increased the expression of miR-34a in renal tissues. The in vitro data showed that the upregulation of miR-34a suppressed, whereas the inhibition of miR-34a promoted, autophagy in RTECs. Moreover, miR-34a could directly bind to Atg4B 3′-untranslated region. In addition, the knockdown of Atg4B expression inhibited the autophagic activity in RTECs. Conclusion: This study indicated that miR-34a might regulate the autophagic activity and can cause injury in I/R RTECs via targeting Atg4B.

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.


2020 ◽  
Author(s):  
Yifei Ren ◽  
Ying Chen ◽  
Xizi Zheng ◽  
Hui Wang ◽  
Xin Kang ◽  
...  

Abstract Background: Acute kidney injury (AKI) is a common clinical disease with complex pathophysiology and very limited therapeutic choices. This prompts the need for novel therapy targeting multiple aspects of this disease. Human amnion epithelial cells (hAECs) are ideal alternative stem cell source for regenerative medicine. Increasing evidence suggests that hAEC-derived exosomes (hAECs-EXO) may act as novel cell–cell communicators. Accordingly, we assessed the therapeutic potential of hAECs in ischemia reperfusion mouse model of AKI and explored the underlying mechanisms.Methods: The hAECs were primary cultured and hAECs-EXO were isolated and characterized. An ischemic renal injury mouse model was established to mimic different severity of the kidney injury. Mouse blood creatinine level was used to assess renal function and kidney specimens were processed to detect cell proliferation, apoptosis and angiogenesis. Immune cells infiltration was analyzed by flow cytometry. hAECs-EXO was used to treat hypoxia-reoxygenation (H/R) injured HK2 cells and mouse bone marrow-derived macrophages to evaluate their protective effect in vitro. Furthermore, hAEC exosomes were subjected to liquid chromatography-tandem mass spectrometry for proteomic profiling. Results: We found that systematically administered hAECs could improve mortality and renal function in IRI mice; decrease the number of apoptotic cells; promote peritubular capillary regeneration and modulate kidney local immune response. However, hAECs showed very low kidney tissue integration. Exosomes isolated from hAECs recapitulated the renal protective effects of their parent cells. In vitro, hAECs-EXO protected HK-2 cells from H/R injury-induced apoptosis and promoted bone marrow-derived macrophage polarization toward M2 phenotype. Proteomic analysis on hAECs-EXO revealed proteins involved in extracellular matrix organization, growth factor signaling pathways, cytokine production and immunomodulation. These findings demonstrated that paracrine of exosomes might be a key mechanism by hAECs mediating kidney functional recovery in AKI.Conclusions: We first reported hAECs could improve mortality and renal repair in mice with ischemia-reperfusion injury. The anti-apoptotic, pro-angiogenetic, and immunomodulatory capabilities of hAECs at least partially, through paracrine pathways. The renoprotective effects of hAECs-EXO might be a promising clinical therapeutic tool, overcoming the weaknesses and risks associated with the use of native stem cells for patients with AKI.


2019 ◽  
Vol 44 (4) ◽  
pp. 465-478 ◽  
Author(s):  
Zhiming Ye ◽  
Li Zhang ◽  
Ruizhao Li ◽  
Wei Dong ◽  
Shuangxin Liu ◽  
...  

Background/Aims: Acute kidney injury (AKI) is a serious complication of sepsis and has a high morbidity and mortality rate. Caspase-11 induces pyroptosis, a form of programmed cell death that plays a critical role in endotoxic shock, but its role in tubular epithelial cell death and whether it contributes to sepsis-associated AKI remains unknown. Methods: The caspase-11–/– mouse received an intraperitoneal injection of lipopolysaccharide (LPS, 40 mg/kg body weight). Caspase-11–/– renal tubular epithelial cells (RTECs) form C57BL caspase-11–/– mice were treated with LPS in vitro. The IL-1β ELISA kit and Scr assay kit were used to measure the level of interleukin-1β and serum creatinine. Annexin V-FITC assay and TUNEL staining assay were used to detect the cell death in different groups in vitro and in vivo. Western blot was performed to analyze the protein expression of caspase-11 and Gsdmdc1. Results: LPS-induced sepsis results in lytic death of RTECs, accompanied by increased expression of the pyroptosis-related proteins caspase-11 and Gsdmd. However, the increase in pyroptosis-related protein expression induced by LPS was attenuated with caspase-11 knockout, both in vitro and in vivo. Furthermore, when challenged with lethal doses of systemic LPS, pathologic abnormalities in renal structure, increased serum and kidney interleukin-1β, increased serum creatinine, and animal death were observed in wild-type mice but prevented in caspase-11–/– mice. Conclusions: Caspase-11-induced pyroptosis of RTECs is a key event during septic AKI, and targeting of caspase-11 in RTECs may serve as a novel therapeutic target in septic AKI.


2020 ◽  
Vol 134 (13) ◽  
pp. 1593-1612
Author(s):  
Chia-Lin Wu ◽  
Chia-Chu Chang ◽  
Tao-Hsiang Yang ◽  
Alexander Charng-Dar Tsai ◽  
Jui-Lin Wang ◽  
...  

Abstract Transcriptional co-activator with PDZ-binding motif (TAZ) is a key downstream effector of the Hippo tumor-suppressor pathway. The functions of TAZ in the kidney, especially in tubular epithelial cells, are not well-known. To elucidate the adaptive expression, protective effects on kidney injury, and signaling pathways of TAZ in response to acute kidney injury (AKI), we used in vitro (hypoxia-treated human renal proximal tubular epithelial cells [RPTECs]) and in vivo (mouse ischemia–reperfusion injury [IRI]) models of ischemic AKI. After ischemic AKI, TAZ was up-regulated in RPTECs and the renal cortex or tubules. Up-regulation of TAZ in RPTECs subjected to hypoxia was controlled by IκB kinase (IKK)/nuclear factor κ-light-chain-enhancer of activated B cell (NF-κB) signaling. TAZ overexpression attenuated hypoxic and oxidative injury, inhibited apoptosis and activation of p38 and c-Jun N-terminal kinase (JNK) proteins, and promoted wound healing in an RPTEC monolayer. However, TAZ knockdown aggravated hypoxic injury, apoptosis, and activation of p38 and JNK signaling, delayed wound closure of an RPTEC monolayer, and promoted G0/G1 phase cell-cycle arrest. Chloroquine and verteporfin treatment produced similar results to TAZ overexpression and knockdown in RPTECs, respectively. Compared with vehicle-treated mice, chloroquine treatment increased TAZ in the renal cortex and tubules, improved renal function, and attenuated tubular injury and tubular apoptosis after renal IRI, whereas TAZ siRNA and verteporfin decreased TAZ in the renal cortex and tubules, deteriorated renal failure and tubular injury, and aggravated tubular apoptosis. Our findings indicate the renoprotective role of tubular TAZ in ischemic AKI. Drugs augmenting (e.g., chloroquine) or suppressing (e.g., verteporfin) TAZ in the kidney might be beneficial or deleterious to patients with AKI.


2019 ◽  
Vol 34 (10) ◽  
pp. 1669-1680 ◽  
Author(s):  
Takamasa Iwakura ◽  
Zhibo Zhao ◽  
Julian A Marschner ◽  
Satish Kumar Devarapu ◽  
Hideo Yasuda ◽  
...  

AbstractBackgroundCisplatin is an effective chemotherapeutic agent. However, acute kidney injury (AKI) and subsequent kidney function decline limits its use. Dipeptidyl peptidase-4 (DPP-4) inhibitor has been reported to attenuate kidney injury in some in vivo models, but the mechanisms-of-action in tubule recovery upon AKI remain speculative. We hypothesized that DPP-4 inhibitor teneligliptin (TG) can facilitate kidney recovery after cisplatin-induced AKI.MethodsIn in vivo experiment, AKI was induced in rats by injecting 5 mg/kg of cisplatin intravenously. Oral administration of 10 mg/kg of TG, once a day, was started just before injecting cisplatin or from Day 5 after cisplatin injection. In an in vitro experiment, proliferation of isolated murine tubular cells was evaluated with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, cell cycle analysis and cell counting. Cell viability was analysed by MTT assay or lactate dehydrogenase (LDH) assay.ResultsIn in vivo experiments, we found that TG attenuates cisplatin-induced AKI and accelerates kidney recovery after the injury by promoting the proliferation of surviving epithelial cells of the proximal tubule. TG also suppressed intrarenal tumour necrosis factor-α expression, and induced macrophage polarization towards the anti-inflammatory M2 phenotype, both indirectly endorsing tubule recovery upon cisplatin injury. In in vitro experiments, TG directly accelerated the proliferation of primary tubular epithelial cells. Systematic screening of the DPP-4 substrate chemokines in vitro identified CXC chemokine ligand (CXCL)-12 as a promoted mitogenic factor. CXCL12 not only accelerated proliferation but also inhibited cell death of primary tubular epithelial cells after cisplatin exposure. CXC chemokine receptor (CXCR)-4 antagonism abolished the proliferative effect of TG.ConclusionsThe DPP-4 inhibitor TG can accelerate tubule regeneration and functional recovery from toxic AKI via an anti-inflammatory effect and probably via inhibition of CXCL12 breakdown. Hence, DPP-4 inhibitors may limit cisplatin-induced nephrotoxicity and improve kidney function in cancer patients.


2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Weiwei Xia ◽  
Yuanyuan Li ◽  
Mengying Wu ◽  
Qianqian Jin ◽  
Qian Wang ◽  
...  

AbstractPyroptosis, one kind of inflammatory regulated cell death, is involved in various inflammatory diseases, including acute kidney injury (AKI). Besides Gasdermin D (GSDMD), GSDME is a newly identified mediator of pyroptosis via the cleavage of caspase-3 generating pyroptotic GSDME-N. Here, we investigated the role of GSDME in renal cellular pyroptosis and AKI pathogenesis employing GSDME-deficient mice and human tubular epithelial cells (TECs) with the interventions of pharmacological and genetic approaches. After cisplatin treatment, GSDME-mediated pyroptosis was induced as shown by the characteristic pyroptotic morphology in TECs, upregulated GSDME-N expression and enhanced release of IL-1β and LDH, and decreased cell viability. Strikingly, silencing GSDME in mice attenuated acute kidney injury and inflammation. The pyroptotic role of GSDME was also verified in human TECs in vitro. Further investigation showed that inhibition of caspase-3 blocked GSDME-N cleavage and attenuated cisplatin-induced pyroptosis and kidney dysfunction. Moreover, deletion of GSDME also protected against kidney injury induced by ischemia-reperfusion. Taken together, the findings from current study demonstrated that caspase-3/GSDME-triggered pyroptosis and inflammation contributes to AKI, providing new insights into the understanding and treatment of this disease.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Lin Wang ◽  
Yan Xu

Abstract Background and Aims Renal ischemia/reperfusion (I/R) is the main cause for acute kidney injury, Nicotiflorin can ameliorate ischemia/reperfusion injury in other organs, just like in cerebral ischemic damage. Therefore, this article intends to explore whether Nicotiflorin has protective effects on renal tubular epithelial cell after ischemia-reperfusion. On the one hand, We use C57 mice to establish the Nicotiflorin group, DMSO group, AKI group, sham group and control group to investigate whether Nicotiflorin can ameliorate ischemia-reperfusion injury of kidney. In other hand, we use CCK8 to explore the optimal concentration of Nicotiflorin in renal tubular epithelial cells and find optimal hypoxia oxygenation time, in order to analysis the influence of Nicotiflorin. The results indicate that Nicotiflorin can alleviate ischemia-reperfusion injury by reducing apoptosis of renal tubular epithelial cells. Method In this study, we investigated the protective mechanism of Nicotiflorin on ischemic acute kidney injury by analyzing gene chip in patients with acute kidney injury and proving in vitro and in vivo experiments. The main methods are as follows: (1) Multiple nucleus ischemia-reperfusion model transcriptase data were selected from the NCBI GEO Datasets database and analyzed to screen out related proteins that may be involved in ischemia-reperfusion kidney injury; (2) The tertiary structure of Nicotiflorin and related proteins was obtained from the SWISS-MODEL database and the PubChem compound database. The molecular docking between protein and Nicotiflorin was performed using Autodock software, and the binding energy between Nicotiflorin and the selected protein was analyzed to determine Nicotiflorin binds to each other; (3) We set different groups, such as control group, sham group, AKI group, Nicotiflorin group and DMSO group in animals. The blood function was used to detect renal injury related function indicators 24 hours after modeling. Renal tissue samples were collected for real-time fluorescent RT-PCR, Western blotting and histopathological analysis; (4)Renal tubular epithelial cells were treated with different concentrations of Nicotiflorin, CCK8 was screened for the most appropriate concentration, and the hypoxic and reoxygenated cells were intervened at the concentration to explore the interaction between Nicotiflorin and the docking protein, and to observe the protective mechanism of Nicotiflorin on the kidney Results Conclusion Nicotiflorin binds to ATF3 and promotes the expression of Cyr61 through protein interactions to improve renal ischemia-reperfusion injury.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Line Stattau Bisgaard ◽  
Pernille M Christensen ◽  
Ernst-Martin Füchtbauer ◽  
Lars Bo Nielsen ◽  
Christina Christoffersen

Abstract Background and Aims Acute kidney injury is a severe disease with detrimental outcomes. The underlying ethiology is still elusive and besides dialysis, treatment options are poor. Apolipoprotein M (apoM) is mainly expressed in liver and in proximal tubular epithelial cells in the kidney. In plasma, apoM associates with HDL particles via a retained signal peptide. ApoM is a carrier of sphingosine-1-phosphate (S1P), a small bioactive lipid involved in e.g. angiogenesis, lymphocyte trafficking, and vascular barrier function. Recently, it was shown that apoM/S1P protects against development of liver and lung fibrosis. In urine, apoM is normally undetectable in both wild type mice and healthy humans. However, lack of megalin receptors in proximal tubuli induces loss of apoM into the urine. The biological function of kidney-derived apoM is unknown, but it has been hypothesized that apoM might be secreted to the pre-urine to sequester molecules, such as S1P, from secretion. The aim of this study was to unravel the role of apoM in kidney biology and in acute kidney injury. Method A novel kidney specific human apoM transgenic mouse (RPTEC-hapoMTG), was generated by expressing human apoM under the control of the proximal tubular epithelial cell specific Sglt2 promoter. The effect of kidney specific apoM overexpression on acute kidney injury was accessed by inducing either cisplatin or ischemia/reperfusion injury. Further, a stable cell line of HK-2 cells overexpressing hapoM (HK-2hapoM-TG) was generated and the cells were cultured on transwells to assess the secretion of apoM to respectively the apical and basolateral site. Results hapoM was present in plasma from RPTEC-hapoMTG mice (mean 0.18 μM), indicating that kidney-derived apoM can be secreted to plasma. When assessing the secretion of hapoM from proximal tubular epithelial cells in vitro, studies support that apoM can be secreted to both the apical (urine) and basolateral (blood) compartment. No differences in kidney injury markers (plasma urea and creatinine) between RPTEC-hapoMTG and wild type (WT) mice subjected to cisplatin injections, or in kidney injury score determined by histological evaluation was found. Similar, we could not detect any histological difference between RPTEC-hapoMTG and WT mice after ischemia/reperfusion injury, and overexpression of hapoM did not affect kidney gene expression of inflammatory markers (i.e. IL6, MCP-1) compared to WT mice. Conclusion Our study suggests that apoM can be secreted to both the apical and basolateral compartment, supporting a role for apoM in sequestering molecules from secretion in urine. Transgenic overexpression of apoM in proximal tubular epithelial cells of mice did not protect against acute kidney injury.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qian Dou ◽  
Hang Tong ◽  
Yichun Yang ◽  
Han Zhang ◽  
Hua Gan

We performed in vitro and in vivo experiments to explore the role of protein kinase C-binding protein 1 (PICK1), an intracellular transporter involved in oxidative stress-related neuronal diseases, in sepsis-related acute kidney injury (AKI). Firstly, PCR, western blotting, and immunohistochemistry were used to observe the expression of PICK1 after lipopolysaccharide- (LPS-) induced AKI. Secondly, by inhibiting PICK1 in vivo and silencing PICK1 in vitro, we further explored the effect of PICK1 on AKI. Finally, the relationship between PICK1 and oxidative stress and the related mechanisms were explored. We found that the expression of PICK1 was increased in LPS-induced AKI models both in vitro and in vivo. PICK1 silencing significantly aggravated LPS-induced apoptosis, accompanied by ROS production in renal tubular epithelial cells. FSC231, a PICK1-specific inhibitor, aggravated LPS-induced kidney injury. Besides, NAC (N-acetylcysteine), a potent ROS scavenger, significantly inhibited the PICK1-silencing-induced apoptosis. In conclusion, PICK1 might protect renal tubular epithelial cells from LPS-induced apoptosis by reducing excessive ROS, making PICK1 a promising preventive target in LPS-induced AKI.


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