Bid activation in kidney cells following ATP depletion in vitro and ischemia in vivo

2004 ◽  
Vol 286 (4) ◽  
pp. F803-F809 ◽  
Author(s):  
Qingqing Wei ◽  
Mohammad M. Alam ◽  
Mong-Heng Wang ◽  
Fushin Yu ◽  
Zheng Dong
Keyword(s):  
Rat Kidney ◽  
Ischemia Reperfusion ◽  
Proteolytic Processing ◽  
Renal Ischemia ◽  
Atp Depletion ◽  
Kidney Cells ◽  
Mitochondrial Uncoupling ◽  
Metabolic Substrates

Bid is a proapoptotic Bcl-2 family protein, which on activation translocates to mitochondria and induces damage to the organelles. Activation of Bid depends on its proteolytic processing into truncated forms of tBid. Bid is highly expressed in the kidneys; however, little is known about its role in renal pathophysiology. In this study, we initially examined Bid activation in cultured rat kidney proximal tubular cells following ATP depletion. The cells were depleted of ATP by azide incubation in the absence of metabolic substrates and then returned to normal culture medium for recovery. Typical apoptosis developed during recovery of ATP-depleted cells. This was accompanied by Bid cleavage, releasing tBid of 15 and 13 kDa. Bid cleavage was abolished in cells overexpressing Bcl-2, an antiapoptotic gene. It was also suppressed by caspase inhibitors. Peptide inhibitors of caspase-9 were more effective in blocking Bid cleavage compared with inhibitors of caspase-8 and caspase-3. Provision of glucose, a glycolytic substrate, during azide incubation inhibited Bid cleavage as well, indicating that Bid cleavage was initiated by ATP depletion. Consistently, Bid cleavage was also induced following ATP depletion by hypoxia or mitochondrial uncoupling. Of significance, cleaved Bid translocated to mitochondria, suggesting a role for Bid in the development of mitochondrial defects in ATP-depleted cells. Finally, Bid cleavage was induced during renal ischemia-reperfusion in the rat. Together, these results provide the first evidence for Bid activation in kidney cells following ATP depletion in vitro and renal ischemia in vivo.

scholarly journals Poly-IC Preconditioning Protects against Cerebral and Renal Ischemia-Reperfusion Injury

2011 ◽  
Vol 32 (2) ◽  
pp. 242-247 ◽  
Author(s):  
Amy E B Packard ◽  
Jason C Hedges ◽  
Frances R Bahjat ◽  
Susan L Stevens ◽  
Michael J Conlin ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Ischemia ◽  
Cortical Cells ◽  
Polycytidylic Acid ◽  
Populations At Risk

Preconditioning induces ischemic tolerance, which confers robust protection against ischemic damage. We show marked protection with polyinosinic polycytidylic acid (poly-IC) preconditioning in three models of murine ischemia-reperfusion injury. Poly-IC preconditioning induced protection against ischemia modeled in vitro in brain cortical cells and in vivo in models of brain ischemia and renal ischemia. Further, unlike other Toll-like receptor (TLR) ligands, which generally induce significant inflammatory responses, poly-IC elicits only modest systemic inflammation. Results show that poly-IC is a new powerful prophylactic treatment that offers promise as a clinical therapeutic strategy to minimize damage in patient populations at risk of ischemic injury.

Effects of phosphate-induced hyperparathyroidism and parathyroidectomy on rat kidney calcium in vivo

1981 ◽  
Vol 241 (2) ◽  
pp. E136-E141 ◽  
Author(s):  
A. B. Borle ◽  
I. Clark
Keyword(s):  
Calcium Metabolism ◽  
Rat Kidney ◽  
Normal Diet ◽  
Kidney Cells ◽  
Elevated Plasma ◽  
Plasma Phosphate ◽  
High Phosphate ◽  
Stimulation Of

The effects of a high-phosphate diet on the calcium metabolism of kidney cells were studied in intact and parathyroidectomized (PTX) rats. The control and the PTX rats were pair-fed a normal diet with a Ca/P of 2:1 or a high-phosphate diet with a Ca/P of 1:8 for 6 wk (chronic experiments) or 1, 3, and 6 days (acute experiments). Renal cell calcium metabolism was studied by chemical and kinetic analyses in kidney slices incubated in vitro. In the control rats the high-phosphate diet significantly increased kidney and mitochondrial calcium, the cytosolic and mitochondrial exchangeable calcium pools, and all calcium fluxes. In these controls, the plasma phosphate was not significantly elevated, but the parathyroid hormone (PTH) levels tended to be high. In PTX rats fed the same high-phosphate diet, the plasma phosphate was significantly elevated, but no change in renal calcium metabolism occurred. These results suggest that nephrocalcinosis was caused by elevated PTH levels and not by the elevated plasma phosphate and that the first step in the development of nephrocalcinosis is a stimulation of cellular calcium metabolism and transport.

scholarly journals SO041THE EFFECT AND MECAHNISM OF THE LOX IN AT1R/Β-ARRESTIN BIASED PATHWAY INDUCED RENAL INTERSTITIAL FIBROSIS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Xiaoqin Zhang ◽  
Chen Yu
Keyword(s):  
Renal Fibrosis ◽  
Interstitial Fibrosis ◽  
Lysyl Oxidase ◽  
Rat Kidney ◽  
Ischemia Reperfusion ◽  
Mek Inhibitor ◽  
Collagen Crosslinking ◽  
Fibrosis Progression

Abstract Background and Aims We studied the downstream and mechanism of β-arrestins signaling in renal fibrosis process and the role of lysyl oxidase (LOX) in the AT1R-β-arrestins pathway. Method The mechanism of β-arrestins signaling was studied in normal rat kidney tubule epithelial cells (NRK-52E) treated with SII in vitro. BAPN or placebo was administered during ischemia reperfusion (IR)-induced fibrosis progression. Collagen crosslinking and fibrosis progression were assessed histologically and biochemically. Results The mRNA and protein levels of β-arrestin-1 and β-arrestin-2 were significantly upregulated in renal fibrosis model both in vitro and in vivo. SII activated the ERK-STAT3 PY705 but not STAT3-Try727 in nucleus of NRK-52E cells, which effects were abolished when transfection of siRNA targeting β-arrestin-1 and β-arrestin-2 or pretreated with PD98059 (MEK inhibitor). LOX was strongly induced in fibrotic kidney and NRK-52E cells treated with SII. Active LOX significantly increased collagen crosslinking. In established IR-28d renal fibrosis, LOX inhibition promoted fibrosis reversal and with a 25% decrease insoluble collagen. Gene silencing of β-arrestin-1 + 2 or STAT3 apparently inhibited SII-induced LOX expression in vitro. Besides, chromatin immunoprecipitation (ChIP) assay clearly demonstrating the interaction between STAT3 and the LOX promoter, which indicated LOX is a direct target gene of SII-β-arrestins-STAT3 signaling. Conclusion The ERK/STAT3 was downstream of AT1R-β-arrestins, ERK entered the nucleus and activated STAT3-PY705. LOX mediates collagen crosslinking and fibrotic matrix stabilization during renal fibrosis via the AT1R-β-arrestins-ERK-STAT3-PY705 signaling. By blocking this profibrotic pathway, therapeutic LOX inhibition attenuates the fibrosis and suggesting target the LOX has significant potency for the treatment of patients with fibrotic kidney disorders.

Nitric oxide-induced regulation of renal organic cation transport after renal ischemia-reperfusion injury

2011 ◽  
Vol 301 (5) ◽  
pp. F997-F1004 ◽  
Author(s):  
R. Schneider ◽  
M. Meusel ◽  
B. Betz ◽  
M. Kersten ◽  
K. Möller-Ehrlich ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Organic Cation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Fractional Excretion ◽  
Renal Ischemia ◽  
Organic Cation Transporters ◽  
Cation Transporters

Renal organic cation transporters are downregulated by nitric oxide (NO) in rat endotoxemia. NO generated by inducible NO synthase (iNOS) is substantially increased in the renal cortex after renal ischemia-reperfusion (I/R) injury. Therefore, we investigated the effects of iNOS-specific NO inhibition on the expression of the organic cation transporters rOct1 and rOct2 (Slc22a1 and Slc22a2, respectively) after I/R injury both in vivo and in vitro. In vivo, N6-(1-iminoethyl)-l-lysine (l-NIL) completely inhibited NO generation after I/R injury. Moreover, l-NIL abolished the ischemia-induced downregulation of rOct1 and rOct2 as determined by qPCR and Western blotting. Functional evidence was obtained by measuring the fractional excretion (FE) of the endogenous organic cation serotonin. Concordant with the expression of the rate-limiting organic cation transporter, the FE of serotonin decreased after I/R injury and was totally abolished by l-NIL. In vitro, ischemia downregulated both rOct1 and rOct2, which were also abolished by l-NIL; the same was true for the uptake of the organic cation MPP. We showed that renal I/R injury downregulates rOct1 and rOct2, which is most probably mediated via NO. In principle, this may be an autocrine effect of proximal tubular epithelial cells. We conclude that rOct1, or rOct1 and rOct2 limit the rate of the renal excretion of serotonin.

A naturally occurring FXR agonist, alisol B 23-acetate, protects against renal ischemia-reperfusion injury

2021 ◽  
Author(s):  
Zhi-Lin Luan ◽  
Wen-Hua Ming ◽  
Xiao-Wan Sun ◽  
Cong Zhang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Renal Ischemia ◽  
Farnesoid X Receptor ◽  
Site Directed Mutagenesis ◽  
Luciferase Assay ◽  
Naturally Occurring

The ligand-activated nuclear receptor, farnesoid X receptor (FXR), plays a pivotal role in regulating renal function. Activation of FXR by its specific agonists exerts renoprotective action in animals with acute kidney injury (AKI). In the present study, we aimed to identify naturally occurring agonists of FXR with potential as therapeutic agents in renal ischemia-perfusion injury (IRI). In vitro and in vivo FXR activation was determined by dual-luciferase assay, docking analysis, site-directed mutagenesis, and whole kidney transcriptome analysis. Wild-type (WT) and FXR knockout (FXR-/-) mice were used to determine the effect of potential FXR agonist on renal IRI. We found that alisol B 23-acetate (ABA), a major active triterpenoid extracted from Alismatis Rhizoma, a well-known traditional Chinese medicine, can activate renal FXR and induce FXR downstream gene expression in mouse kidney. ABA treatment significantly attenuated renal IR-induced AKI in WT mice but not in FXR-/- mice. Our results demonstrate that ABA can activate renal FXR to exert renoprotection against IRI-induced AKI. Therefore, ABA may represent a potential therapeutic agent in the treatment of ischemic AKI.

Trehalose attenuates renal ischemia-reperfusion injury by enhancing autophagy and inhibiting oxidative stress and inflammation

2020 ◽  
Vol 318 (4) ◽  
pp. F994-F1005
Author(s):  
Suwen Liu ◽  
Yunwen Yang ◽  
Huiping Gao ◽  
Ning Zhou ◽  
Peipei Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Renal Function ◽  
Renal Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Renal Ischemia ◽  
Renal Histology ◽  
Hypoxia Reoxygenation

Renal ischemia-reperfusion (IR) injury is one of the most common acute kidney injuries, but there is still a lack of effective treatment in the clinical setting. Trehalose (Tre), a natural disaccharide, has been demonstrated to protect against oxidative stress, inflammation, and apoptosis. However, whether it could protect against IR-induced renal injury needs to be investigated. In an in vivo experiment, C57BL/6J mice were pretreated with or without Tre (2 g/kg) through a daily single intraperitoneal injection from 3 days before renal IR surgery. Renal function, apoptosis, oxidative stress, and inflammation were analyzed to evaluate kidney injury. In an in vitro experiment, mouse proximal tubular cells were treated with or without Tre under a hypoxia/reoxygenation condition. Western blot analysis, autophagy flux detection, and apoptosis assay were performed to evaluate the level of autophagy and antiapoptotic effect of Tre. The in vivo results showed that the renal damage induced by IR was ameliorated by Tre treatment, as renal histology and renal function were improved and the enhanced protein levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin were blocked. Moreover, autophagy was activated by Tre pretreatment along with inhibition of the IR injury-induced apoptosis, oxidative stress, and inflammation. The in vitro results showed that Tre treatment activated autophagy and protected against hypoxia/reoxygenation-induced tubular cell apoptosis and oxidative stress. Our results demonstrated that Tre protects against IR-induced renal injury, possibly by enhancing autophagy and blocking oxidative stress, inflammation, and apoptosis, suggesting its potential use for the clinical treatment of renal IR injury.

scholarly journals Cilastatin Preconditioning Attenuates Renal Ischemia-Reperfusion Injury via Hypoxia Inducible Factor-1α Activation

2020 ◽  
Vol 21 (10) ◽  
pp. 3583
Author(s):  
Yu Ah Hong ◽  
So Young Jung ◽  
Keum Jin Yang ◽  
Dai Sig Im ◽  
Kyung Hwan Jeong ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hypoxia Inducible Factor ◽  
Specific Inhibitor ◽  
Renal Ischemia ◽  
Dependent Manner ◽  
Hypoxia Inducible Factor 1Α ◽  
Downstream Signaling

Cilastatin is a specific inhibitor of renal dehydrodipeptidase-1. We investigated whether cilastatin preconditioning attenuates renal ischemia-reperfusion (IR) injury via hypoxia inducible factor-1α (HIF-1α) activation. Human proximal tubular cell line (HK-2) was exposed to ischemia, and male C57BL/6 mice were subjected to bilateral kidney ischemia and reperfusion. The effects of cilastatin preconditioning were investigated both in vitro and in vivo. In HK-2 cells, cilastatin upregulated HIF-1α expression in a time- and dose-dependent manner. Cilastatin enhanced HIF-1α translation via the phosphorylation of Akt and mTOR was followed by the upregulation of erythropoietin (EPO) and vascular endothelial growth factor (VEGF). Cilastatin did not affect the expressions of PHD and VHL. However, HIF-1α ubiquitination was significantly decreased after cilastatin treatment. Cilastatin prevented the IR-induced cell death. These cilastatin effects were reversed by co-treatment of HIF-1α inhibitor or HIF-1α small interfering RNA. Similarly, HIF-1α expression and its upstream and downstream signaling were significantly enhanced in cilastatin-treated kidney. In mouse kidney with IR injury, cilastatin treatment decreased HIF-1α ubiquitination independent of PHD and VHL expression. Serum creatinine level and tubular necrosis, and apoptosis were reduced in cilastatin-treated kidney with IR injury, and co-treatment of cilastatin with an HIF-1α inhibitor reversed these effects. Thus, cilastatin preconditioning attenuated renal IR injury via HIF-1α activation.

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