scholarly journals Characterization of urinary exosomal release of aquaporin-1 and -2 after renal ischemia-reperfusion in rats

2018 ◽  
Vol 314 (4) ◽  
pp. F584-F601 ◽  
Author(s):  
Siree Asvapromtada ◽  
Hiroko Sonoda ◽  
Minami Kinouchi ◽  
Sayaka Oshikawa ◽  
Saki Takahashi ◽  
...  

Acute kidney injury (AKI) is an important risk factor for the development of chronic kidney disease (CKD), and an alteration in renal water handling has been observed during the transition of AKI to CKD. Urinary exosomal release of aquaporin-1 (AQP1) and AQP2, important proteins for renal water handling, has recently been reported to predict their levels of renal expression. Therefore, we examined the patterns of urinary exosomal release of AQP1 and AQP2, and the exosomal marker proteins tumor susceptibility 101 protein (TSG101) and ALG-2 interacting protein X (Alix), in the acute and chronic phases following induction of AKI by renal bilateral ischemia/reperfusion (I/R) in rats. Blood tests and histological examinations indicated that AKI occurred before at 7 days after renal I/R ( day 7) and that renal fibrosis developed progressively thereafter. Immunoblotting demonstrated significant decreases in the urinary exosomal release of AQP1 and AQP2 during severe AKI. Urinary exosomal release of Alix and TSG101 was significantly increased on day 7. These data were also confirmed in rats with unilateral renal I/R causing more serious AKI. Urinary exosomal release of either the Ser-256- or Ser-269-phosphorylated form of AQP2, both of which are involved in apical trafficking of AQP2, was positively correlated with that of total AQP2. These results suggest that urinary exosomal release of AQP1 and AQP2 is reduced in I/R-induced AKI, whereas that of Alix and TSG101 is increased in the initial phase of renal fibrosis. Furthermore, apical trafficking of AQP2 appears to be related to urinary exosomal release of AQP2.

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 347 ◽  
Author(s):  
Miguel Fontecha-Barriuso ◽  
Diego Martin-Sanchez ◽  
Julio Manuel Martinez-Moreno ◽  
Maria Monsalve ◽  
Adrian Mario Ramos ◽  
...  

Chronic kidney disease (CKD) is one of the fastest growing causes of death worldwide, emphasizing the need to develop novel therapeutic approaches. CKD predisposes to acute kidney injury (AKI) and AKI favors CKD progression. Mitochondrial derangements are common features of both AKI and CKD and mitochondria-targeting therapies are under study as nephroprotective agents. PGC-1α is a master regulator of mitochondrial biogenesis and an attractive therapeutic target. Low PGC-1α levels and decreased transcription of its gene targets have been observed in both preclinical AKI (nephrotoxic, endotoxemia, and ischemia-reperfusion) and in experimental and human CKD, most notably diabetic nephropathy. In mice, PGC-1α deficiency was associated with subclinical CKD and predisposition to AKI while PGC-1α overexpression in tubular cells protected from AKI of diverse causes. Several therapeutic strategies may increase kidney PGC-1α activity and have been successfully tested in animal models. These include AMP-activated protein kinase (AMPK) activators, phosphodiesterase (PDE) inhibitors, and anti-TWEAK antibodies. In conclusion, low PGC-1α activity appears to be a common feature of AKI and CKD and recent characterization of nephroprotective approaches that increase PGC-1α activity may pave the way for nephroprotective strategies potentially effective in both AKI and CKD.


PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183701 ◽  
Author(s):  
Juan S. Danobeitia ◽  
Martynas Ziemelis ◽  
Xiaobo Ma ◽  
Laura J. Zitur ◽  
Tiffany Zens ◽  
...  

2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Huizhen Wang ◽  
Yifan Wang ◽  
Xin Wang ◽  
Huimi Huang ◽  
Jingfu Bao ◽  
...  

AbstractPhosphatase and Tensin Homolog on chromosome Ten (PTEN) has emerged as a key protein that governs the response to kidney injury. Notably, renal adaptive repair is important for preventing acute kidney injury (AKI) to chronic kidney disease (CKD) transition. To test the role of PTEN in renal repair after acute injury, we constructed a mouse model that overexpresses PTEN in renal proximal tubular cells (RPTC) by crossing PTENfl-stop-fl mice with Ggt1-Cre mice. Mass spectrometry-based proteomics was performed after subjecting these mice to ischemia/reperfusion (I/R). We found that PTEN was downregulated in renal tubular cells in mice and cultured HK-2 cells subjected to renal maladaptive repair induced by I/R. Renal expression of PTEN negatively correlated with NGAL and fibrotic markers. RPTC-specific PTEN overexpression relieved I/R-induced maladaptive repair, as indicated by alleviative tubular cell damage, apoptosis, and subsequent renal fibrosis. Mass spectrometry analysis revealed that differentially expressed proteins in RPTC-specific PTEN overexpression mice subjected to I/R were significantly enriched in phagosome, PI3K/Akt, and HIF-1 signaling pathway and found significant upregulation of CHMP2A, an autophagy-related protein. PTEN deficiency downregulated CHMP2A and inhibited phagosome closure and autolysosome formation, which aggravated cell injury and apoptosis after I/R. PTEN overexpression had the opposite effect. Notably, the beneficial effect of PTEN overexpression on autophagy flux and cell damage was abolished when CHMP2A was silenced. Collectively, our study suggests that PTEN relieved renal maladaptive repair in terms of cell damage, apoptosis, and renal fibrosis by upregulating CHMP2A-mediated phagosome closure, suggesting that PTEN/CHMP2A may serve as a novel therapeutic target for the AKI to CKD transition.


2013 ◽  
Vol 305 (4) ◽  
pp. F477-F484 ◽  
Author(s):  
Sarah C. Huen ◽  
Gilbert W. Moeckel ◽  
Lloyd G. Cantley

Macrophage infiltration is a prominent feature of the innate immune response to kidney injury. The persistence of macrophages is associated with tubulointerstitial fibrosis and progression of chronic kidney disease. Macrophages are known to be major producers of transforming growth factor-β1 (TGF-β1), especially in the setting of phagocytosis of apoptotic cells. TGF-β1 has long been implicated as a central mediator of tissue scarring and fibrosis in many organ disease models, including kidney disease. In this study, we show that homozygous deletion of Tgfb1 in myeloid lineage cells in mice heterozygous for Tgfb1 significantly reduces kidney Tgfb1 mRNA expression and Smad activation at late time points after renal ischemia-reperfusion injury. However, this reduction in kidney Tgfb1 expression and signaling results in only a modest reduction of isolated fibrosis markers and does not lead to decreased interstitial fibrosis in either ischemic or obstructive injury models. Thus, targeting macrophage-derived TGF-β1 does not appear to be an effective therapy for attenuating progressive renal fibrosis after kidney injury.


2017 ◽  
Vol 43 (5) ◽  
pp. 1841-1854 ◽  
Author(s):  
Jun Zhou ◽  
Jiying  Zhong ◽  
Sen  Lin ◽  
Zhenxing Huang ◽  
Hongtao Chen ◽  
...  

Background: Renal fibrosis is a common pathophysiological feature of chronic kidney disease. Acute kidney injury (AKI) is defined as an independent causal factor of chronic kidney disease, with a pathological representation of post renal fibrosis. However, the etiopathogenesis underlying post renal fibrosis induced by AKI is not completely understood. Methods: BALB/c mice were treated with bpv or vehicle controls and were, respectively, the ischemia reperfusion (IR) model group and control group. All of the animals had blood taken from the orbital venous plexus at 24 hours after IR. Six mice in each group were randomly chosen and euthanized 7 days after IR treatment, and the remaining six mice in each group were euthanized 14 days after IR treatment. We examined the effect on post kidney fibrosis of inhibiting PTEN activity in mice in an IR induced AKI experimental model. Results: Compared with vehicle mice, bpv-(PTEN specific inhibitor) treated mice accumulated more bone marrow-derived fibroblasts and myofibroblasts in the kidneys. Inhibition of PTEN activity increased the expression of α-smooth muscle actin and extracellular matrix proteins and post kidney fibrosis. Furthermore, inhibition of PTEN activity resulted in more inflammatory cytokines in the kidneys of mice subjected to IR-induced renal fibrosis. Moreover, inhibition of PTEN activity up-regulated PI3K protein expression and Akt phosphorylation. Conclusions: Our study demonstrated that PTEN played an important role in post renal fibrosis in mice with ischemia reperfusion-induced AKI. These results indicated that the PTEN/PI3K/Akt signaling pathway may serve as a novel therapeutic target for AKI-induced chronic kidney disease.


2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Jin Ha Park ◽  
Ji Hae Jun ◽  
Jae-Kwang Shim ◽  
Eun Jung Shin ◽  
Eunah Shin ◽  
...  

Even after recovery from acute kidney injury, glomeruli remain vulnerable to further injury by way of interstitial fibrosis. This study is aimed at elucidating the effects of post ischemia-reperfusion (I/R) treatment with trimetazidine on the progression to renal fibrosis as well as short- and intermediate-term aspects. Trimetazidine 3 mg/kg or 0.9% saline was given intraperitoneally once upon reperfusion or daily thereafter for 5 d or 8 w. Renal histologic changes and related signaling proteins were assessed. After 24 h, post I/R treatment with trimetazidine significantly reduced serum blood urea nitrogen and creatinine levels and tubular injury accompanied with upregulation of hypoxia-inducible factor- (HIF-) 1α, vascular endothelial growth factor (VEGF), and Bcl-2 expression. After 5 d, post I/R treatment with trimetazidine reduced renal tubular cell necrosis and apoptosis with upregulation of HIF-1α-VEGF and tissue inhibitors of metalloproteinase activities, attenuation of matrix metalloproteinase activities, and alteration of the ratio of Bax to Bcl-2 levels. After 8 w, however, post I/R treatment with trimetazidine did not modify the progression of renal fibrosis. In conclusion, post I/R treatment with trimetazidine allows ischemic kidneys to regain renal function and structure more rapidly compared to nontreated kidneys, but not enough to resolute renal fibrosis in long-term aspect.


GeroScience ◽  
2021 ◽  
Author(s):  
Tamás Kaucsár ◽  
Beáta Róka ◽  
Pál Tod ◽  
Phuong Thanh Do ◽  
Zoltán Hegedűs ◽  
...  

Abstract Elderly patients have increased susceptibility to acute kidney injury (AKI). Long noncoding RNAs (lncRNA) are key regulators of cellular processes, and have been implicated in both aging and AKI. Our aim was to study the effects of aging and ischemia–reperfusion injury (IRI) on the renal expression of lncRNAs. Adult and old (10- and 26–30-month-old) C57BL/6 N mice were subjected to unilateral IRI followed by 7 days of reperfusion. Renal expression of 90 lncRNAs and mRNA expression of injury, regeneration, and fibrosis markers was measured by qPCR in the injured and contralateral control kidneys. Tubular injury, regeneration, and fibrosis were assessed by histology. Urinary lipocalin-2 excretion was increased in old mice prior to IRI, but plasma urea was similar. In the control kidneys of old mice tubular cell necrosis and apoptosis, mRNA expression of kidney injury molecule-1, fibronectin-1, p16, and p21 was elevated. IRI increased plasma urea concentration only in old mice, but injury, regeneration, and fibrosis scores and their mRNA markers were similar in both age groups. AK082072 and Y lncRNAs were upregulated, while H19 and RepA transcript were downregulated in the control kidneys of old mice. IRI upregulated Miat, Igf2as, SNHG5, SNHG6, RNCR3, Malat1, Air, Linc1633, and Neat1 v1, while downregulated Linc1242. LncRNAs H19, AK082072, RepA transcript, and Six3os were influenced by both aging and IRI. Our results indicate that both aging and IRI alter renal lncRNA expression suggesting that lncRNAs have a versatile and complex role in aging and kidney injury. An Ingenuity Pathway Analysis highlighted that the most downregulated H19 may be linked to aging/senescence through p53.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Ki Ryang Na ◽  
DAE EUN CHOI ◽  
Kang Wook Lee ◽  
Dabi Kim ◽  
Eunji Kim ◽  
...  

Abstract Background and Aims: Hypothermia attenuates the renal injury induced by ischemia-reperfusion(IR). However, the detailed molecular pathway remains unknown. Although there has been reported that hypothermia protects acute renal damage, there is little known that hypothermia reduce renal fibrosis in IR kidney injury. We evaluated hypothermic protection against renal fibrosis in renal IR injury. Method: C57Bl/6 mice were divided into the following groups: sham-operated (cold, 32C) vs normal temperature (37C); IR mice (32C vs 37C). Kidneys were harvested 10 and 27 minutes after induction of renal ischemia and 24, 72, 168 hours after iIR injury. Functional and molecular markers of kidney injury were evaluated. Results: The blood urea nitrogen and serum creatinine levels and the histologic renal injury scores were significantly lower in 32C IR than 37C IR kidneys (all P values < .05).In kidney harvested 10 and 27 min, the extent of renal AMPK,ERK, and HIF1 phosphorylation was significantly increased in the kidneys of 32C compared to 37C IR mice. In kidney harvested 27 min, 24hr, 72hr, and 168hr, the expression levels of SOX9, TGF beta, alpha SMA, collagen IV, and fibrinogen decreased in 32C IR compared to 37C IR mice. In addition, in kidney harvested 72hr, and 168hr, the stained area of TGF beta, alpha SMA, and masson trichrome, were significantly decreased in 32C IR compared to 37C IR mice. Conclusion: Hypothermia attenuates the renal fibrosis induced by Ischemia reperfusion.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wulf Tonnus ◽  
Claudia Meyer ◽  
Christian Steinebach ◽  
Alexia Belavgeni ◽  
Anne von Mässenhausen ◽  
...  

AbstractAcute kidney injury (AKI) is morphologically characterized by a synchronized plasma membrane rupture of cells in a specific section of a nephron, referred to as acute tubular necrosis (ATN). Whereas the involvement of necroptosis is well characterized, genetic evidence supporting the contribution of ferroptosis is lacking. Here, we demonstrate that the loss of ferroptosis suppressor protein 1 (Fsp1) or the targeted manipulation of the active center of the selenoprotein glutathione peroxidase 4 (Gpx4cys/-) sensitize kidneys to tubular ferroptosis, resulting in a unique morphological pattern of tubular necrosis. Given the unmet medical need to clinically inhibit AKI, we generated a combined small molecule inhibitor (Nec-1f) that simultaneously targets receptor interacting protein kinase 1 (RIPK1) and ferroptosis in cell lines, in freshly isolated primary kidney tubules and in mouse models of cardiac transplantation and of AKI and improved survival in models of ischemia-reperfusion injury. Based on genetic and pharmacological evidence, we conclude that GPX4 dysfunction hypersensitizes mice to ATN during AKI. Additionally, we introduce Nec-1f, a solid inhibitor of RIPK1 and weak inhibitor of ferroptosis.


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