scholarly journals Divergent roles for kidney proximal tubule and granulocyte PAD4 in ischemic AKI

2018 ◽  
Vol 314 (5) ◽  
pp. F809-F819 ◽  
Author(s):  
Hongmei Li ◽  
Sang Jun Han ◽  
Mihwa Kim ◽  
Ahyeon Cho ◽  
Yewoon Choi ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Critical Role ◽  
Cell Lineage ◽  
Kidney Injury ◽  
Myeloid Cell ◽  
Neutrophil Infiltration ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Renal Tubular ◽  
Deficient Mice

We previously demonstrated that kidney peptidylarginine deiminase-4 (PAD4) plays a critical role in ischemic acute kidney injury (AKI) in mice by promoting renal tubular inflammation and neutrophil infiltration (Ham A, Rabadi M, Kim M, Brown KM, Ma Z, D’Agati V, Lee HT. Am J Physiol Renal Physiol 307: F1052–F1062, 2014). Although the role of PAD4 in granulocytes including neutrophils is well known, we surprisingly observed profound renal proximal tubular PAD4 induction after renal ischemia-reperfusion (I/R) injury. Here we tested the hypothesis that renal proximal tubular PAD4 rather than myeloid-cell lineage PAD4 plays a critical role in exacerbating ischemic AKI by utilizing mice lacking PAD4 in renal proximal tubules (PAD4ff PEPCK Cre mice) or in granulocytes (PAD4ff LysM Cre mice). Mice lacking renal proximal tubular PAD4 were significantly protected against ischemic AKI compared with wild-type (PAD4ff) mice. Surprisingly, mice lacking PAD4 in myeloid cells were also protected against renal I/R injury although this protection was less compared with renal proximal tubular PAD4-deficient mice. Renal proximal tubular PAD4-deficient mice had profoundly reduced renal tubular apoptosis, whereas myeloid-cell PAD4-deficient mice showed markedly reduced renal neutrophil infiltration. Taken together, our studies suggest that both renal proximal tubular PAD4 as well as myeloid-cell lineage PAD4 play a critical role in exacerbating ischemic AKI. Renal proximal tubular PAD4 appears to contribute to ischemic AKI by promoting renal tubular apoptosis, whereas myeloid-cell PAD4 is preferentially involved in promoting neutrophil infiltration to the kidney and inflammation after renal I/R.

scholarly journals Peptidyl arginine deiminase-4 exacerbates ischemic AKI by finding NEMO

2019 ◽  
Vol 316 (6) ◽  
pp. F1180-F1190 ◽  
Author(s):  
May M. Rabadi ◽  
Sang Jun Han ◽  
Mihwa Kim ◽  
Vivette D’Agati ◽  
H. Thomas Lee
Keyword(s):  
Ischemia Reperfusion ◽  
Critical Role ◽  
Arginine Deiminase ◽  
Proximal Tubular Cell ◽  
Tubular Cell ◽  
Binding Peptide ◽  
Peptidyl Arginine Deiminase ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Renal Tubular

Peptidyl arginine deiminase-4 (PAD4) catalyzes the conversion of peptidylarginine residues to peptidylcitrulline. We have previously shown that kidney ischemia-reperfusion (I/R) injury increases renal proximal tubular PAD4 expression and activity. Furthermore, kidney PAD4 plays a critical role in ischemic acute kidney injury (AKI) by promoting renal tubular inflammation, neutrophil infiltration, and NF-κB activation. However, the mechanisms of PAD4-mediated renal tubular inflammation and NF-κB activation after I/R remain unclear. Here, we show that recombinant PAD4 preferentially citrullinates recombinant IKKγ [also called NF-κB essential modulator (NEMO)] over recombinant IKKα or IKKβ. Consistent with this finding, PAD4 citrullinated renal proximal tubular cell IKKγ and promoted NF-κB activation via IκBα phosphorylation in vitro. NEMO inhibition with a selective NEMO-binding peptide attenuated PAD4-mediated proinflammatory cytokine mRNA induction in HK-2 cells. Moreover, NEMO inhibition did not affect proximal tubular cell survival, proliferation, or apoptosis, unlike global NF-κB inhibition. In vivo, NEMO-binding peptide treatment protected against ischemic AKI. Finally, NEMO-binding peptide attenuated recombinant PAD4-mediated exacerbation of ischemic AKI, renal tubular inflammation, and apoptosis. Taken together, our results show that PAD4 exacerbates ischemic AKI and inflammation by promoting renal tubular NF-κB activity and inflammation via NEMO citrullination. Targeting NEMO activation may serve as a potential therapy for this devastating clinical problem.

scholarly journals Perilipin 2 Impacts Acute Kidney Injury via Regulation of PPARα

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Sujuan Xu ◽  
Edward Lee ◽  
Zhaoxing Sun ◽  
Xiaoyan Wang ◽  
Ting Ren ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Acute Kidney Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Renal Tumors ◽  
Tubular Cells ◽  
Proximal Tubular ◽  
Perilipin 2 ◽  
Renal Proximal Tubular

Renal ischemia-reperfusion (I/R) can induce oxidative stress and injury via the generation of reactive oxygen species (ROS). Renal proximal tubular cells are susceptible to oxidative stress, and the dysregulation of renal proximal tubular cellular homeostasis can damage cells via apoptotic pathways. A recent study showed that the generation of ROS can increase perilipin 2 (Plin2) expression in HepG2 cells. Some evidence has also demonstrated the association between Plin2 expression and renal tumors. However, the underlying mechanism of Plin2 in I/R-induced acute kidney injury (AKI) remains elusive. Here, using a mouse model of I/R-induced AKI, we found that ROS generation was increased and the expression of Plin2 was significantly upregulated. An in vitro study further revealed that the expression of Plin2, and the generation of ROS were significantly upregulated in primary tubular cells treated with hydrogen peroxide. Accordingly, Plin2 knockdown decreased apoptosis in renal proximal tubular epithelial cells treated with hydrogen peroxide, which depended on the activation of peroxisome proliferator-activated receptor α (PPARα). Overall, the present study demonstrated that Plin2 is involved in AKI; knockdown of this marker might limit apoptosis via the activation of PPARα. Consequently, the downregulation of Plin2 could be a novel therapeutic strategy for AKI.

Renal PKC-ε deficiency attenuates acute kidney injury and ischemic allograft injury via TNF-α-dependent inhibition of apoptosis and inflammation

2014 ◽  
Vol 307 (6) ◽  
pp. F718-F726 ◽  
Author(s):  
Song Rong ◽  
Katja Hueper ◽  
Torsten Kirsch ◽  
Robert Greite ◽  
Christian Klemann ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Neutrophil Infiltration ◽  
Major Surgery ◽  
Severe Renal Failure ◽  
Tnf Α ◽  
Apoptosis And Inflammation ◽  
Deficient Mice

Acute kidney injury (AKI) increases the risk of morbidity and mortality after major surgery and transplantation. We investigated the effect of PKC-ε deficiency on AKI and ischemic allograft damage after kidney transplantation. PKC-ε-deficient and wild type (WT) control mice were subjected to 35 min of renal pedicle clamping to induce AKI. PKC-ε deficiency was associated with a marked improvement in survival and an attenuated loss of kidney function. Furthermore, functional MRI experiments revealed better renal perfusion in PKC-ε-deficient mice than in WT mice one day after IRI. Acute tubular necrosis and neutrophil infiltration were markedly reduced in PKC-ε-deficient mice. To determine whether this resistance to ischemia-reperfusion injury resulted from changes in local renal cells or infiltrating leukocytes, we studied a life-supporting renal transplant model of ischemic graft injury. We transplanted kidneys from H2b PKC-ε-deficient mice (129/SV) and their corresponding WT littermates into major histocompatibility complex-incompatible H2d recipients (BALB/c) and induced ischemic graft injury by prolonged cold ischemia time. Recipients of WT allografts developed severe renal failure and died within 10 days of transplantation. Recipients of PKC-ε-deficient allografts had better renal function and survival; they had less generation of ROS and upregulation of proinflammatory proteins (i.e., ICAM-1, inducible nitric oxide synthase, and TNF-α) and showed less tubular epithelial cell apoptosis and inflammation in their allografts. These data suggest that local renal PKC-ε expression mediates proapoptotic and proinflammatory signaling and that an inhibitor of PKC-ε signaling could be used to prevent hypoxia-induced AKI.

scholarly journals Peptidyl arginine deiminase-4 activation exacerbates kidney ischemia-reperfusion injury

2014 ◽  
Vol 307 (9) ◽  
pp. F1052-F1062 ◽  
Author(s):  
Ahrom Ham ◽  
May Rabadi ◽  
Mihwa Kim ◽  
Kevin M. Brown ◽  
Zhe Ma ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Critical Role ◽  
Neutrophil Infiltration ◽  
Cytokine Expression ◽  
Mouse Kidney ◽  
Arginine Deiminase ◽  
Peptidyl Arginine Deiminase ◽  
Inflammatory Protein ◽  
Renal Tubular ◽  
Macrophage Inflammatory Protein

Peptidyl arginine deiminase (PAD)4 is a nuclear enzyme that catalyzes the posttranslational conversion of arginine residues to citrulline. Posttranslational protein citrullination has been implicated in several inflammatory autoimmune diseases, including rheumatoid arthritis, colitis, and multiple sclerosis. Here, we tested the hypothesis that PAD4 contributes to ischemic acute kidney injury (AKI) by exacerbating the inflammatory response after renal ischemia-reperfusion (I/R). Renal I/R injury in mice increased PAD4 activity as well as PAD4 expression in the mouse kidney. After 30 min of renal I/R, vehicle-treated mice developed severe AKI with large increases in plasma creatinine. In contrast, mice pretreated with PAD4 inhibitors (2-chloroamidine or streptonigrin) had significantly reduced renal I/R injury. Further supporting a critical role for PAD4 in generating ischemic AKI, mice pretreated with recombinant human PAD4 (rPAD4) protein and subjected to mild (20 min) renal I/R developed exacerbated ischemic AKI. Consistent with the hypothesis that PAD4 regulates renal tubular inflammation after I/R, mice treated with a PAD4 inhibitor had significantly reduced renal neutrophil chemotactic cytokine (macrophage inflammatory protein-2 and keratinocyte-derived cytokine) expression and had decreased neutrophil infiltration. Furthermore, mice treated with rPAD4 had significantly increased renal tubular macrophage inflammatory protein-2 and keratinocyte-derived cytokine expression as well as increased neutrophil infiltration and necrosis. Finally, cultured mouse kidney proximal tubules treated with rPAD4 had significantly increased proinflammatory chemokine expression compared with vehicle-treated cells. Taken together, our results suggest that PAD4 plays a critical role in renal I/R injury by increasing renal tubular inflammatory responses and neutrophil infiltration after renal I/R.

scholarly journals A1 adenosine receptor allosteric enhancer PD-81723 protects against renal ischemia-reperfusion injury

2012 ◽  
Vol 303 (5) ◽  
pp. F721-F732 ◽  
Author(s):  
Sang Won Park ◽  
Joo Yun Kim ◽  
Ahrom Ham ◽  
Kevin M. Brown ◽  
Mihwa Kim ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Side Effects ◽  
Proximal Tubule ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Wild Type ◽  
Renal Protection ◽  
Ischemic Acute Kidney Injury ◽  
Renal Tubular ◽  
Deficient Mice

Activation of A1 adenosine receptors (ARs) protects against renal ischemia-reperfusion (I/R) injury by reducing necrosis, apoptosis, and inflammation. However, extrarenal side effects (bradycardia, hypotension, and sedation) may limit A1AR agonist therapy for ischemic acute kidney injury. Here, we hypothesized that an allosteric enhancer for A1AR (PD-81723) protects against renal I/R injury without the undesirable side effects of systemic A1AR activation by potentiating the cytoprotective effects of renal adenosine generated locally by ischemia. Pretreatment with PD-81723 produced dose-dependent protection against renal I/R injury in A1AR wild-type mice but not in A1AR-deficient mice. Significant reductions in renal tubular necrosis, neutrophil infiltration, and inflammation as well as tubular apoptosis were observed in A1AR wild-type mice treated with PD-81723. Furthermore, PD-81723 decreased apoptotic cell death in human proximal tubule (HK-2) cells in culture, which was attenuated by a specific A1AR antagonist (8-cyclopentyl-1,3-dipropylxanthine). Mechanistically, PD-81723 induced sphingosine kinase (SK)1 mRNA and protein expression in HK-2 cells and in the mouse kidney. Supporting a critical role of SK1 in A1AR allosteric enhancer-mediated renal protection against renal I/R injury, PD-81723 failed to protect SK1-deficient mice against renal I/R injury. Finally, proximal tubule sphingosine-1-phosphate type 1 receptors (S1P1Rs) are critical for PD-81723-induced renal protection, as mice selectively deficient in renal proximal tubule S1P1Rs (S1P1Rflox/flox PEPCKCre/− mice) were not protected against renal I/R injury with PD-81723 treatment. Taken together, our experiments demonstrate potent renal protection with PD-81723 against I/R injury by reducing necrosis, inflammation, and apoptosis through the induction of renal tubular SK1 and activation of proximal tubule S1P1Rs. Our findings imply that selectively enhancing A1AR activation by locally produced renal adenosine may be a clinically useful therapeutic option to attenuate ischemic acute kidney injury without systemic side effects.

scholarly journals Autophagy Deficiency in Renal Proximal Tubular Cells Leads to an Increase in Cellular Injury and Apoptosis under Normal Fed Conditions

2019 ◽  
Vol 21 (1) ◽  
pp. 155 ◽  
Author(s):  
Chigure Suzuki ◽  
Isei Tanida ◽  
Juan Alejandro Oliva Trejo ◽  
Soichiro Kakuta ◽  
Yasuo Uchiyama
Keyword(s):  
Renal Injury ◽  
Kidney Injury ◽  
Renal Tissue ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular Cells ◽  
Renal Proximal Tubular ◽  
Renal Tubular

Renal proximal tubular epithelial cells are significantly damaged during acute kidney injury. Renal proximal tubular cell-specific autophagy-deficient mice show increased sensitivity against renal injury, while showing few pathological defects under normal fed conditions. Considering that autophagy protects the proximal tubular cells from acute renal injury, it is reasonable to assume that autophagy contributes to the maintenance of renal tubular cells under normal fed conditions. To clarify this possibility, we generated a knock out mouse model which lacks Atg7, a key autophagosome forming enzyme, in renal proximal tubular cells (Atg7flox/flox;KAP-Cre+). Analysis of renal tissue from two months old Atg7flox/flox;KAP-Cre+ mouse revealed an accumulation of LC3, binding protein p62/sequestosome 1 (a selective substrate for autophagy), and more interestingly, Kim-1, a biomarker for early kidney injury, in the renal proximal tubular cells under normal fed conditions. TUNEL (TdT-mediated dUTP Nick End Labeling)-positive cells were also detected in the autophagy-deficient renal tubular cells. Analysis of renal tissue from Atg7flox/flox;KAP-Cre+ mice at different age points showed that tubular cells positive for p62 and Kim-1 continually increase in number in an age-dependent manner. Ultrastructural analysis of tubular cells from Atg7flox/flox;KAP-Cre+ revealed the presence of intracellular inclusions and abnormal structures. These results indicated that autophagy-deficiency in the renal proximal epithelial tubular cells leads to an increase in injured cells in the kidney even under normal fed conditions.

scholarly journals Renal proximal tubular NEMO plays a critical role in ischemic acute kidney injury

JCI Insight ◽  
2020 ◽  
Vol 5 (19) ◽  
Author(s):  
Sang Jun Han ◽  
Ryan M. Williams ◽  
Mihwa Kim ◽  
Daniel A. Heller ◽  
Vivette D’Agati ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Critical Role ◽  
Kidney Injury ◽  
Proximal Tubular ◽  
Ischemic Acute Kidney Injury ◽  
Renal Proximal Tubular

scholarly journals RGMb protects against acute kidney injury by inhibiting tubular cell necroptosis via an MLKL-dependent mechanism

2018 ◽  
Vol 115 (7) ◽  
pp. E1475-E1484 ◽  
Author(s):  
Wenjing Liu ◽  
Binbin Chen ◽  
Yang Wang ◽  
Chenling Meng ◽  
Huihui Huang ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Apical Membrane ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Kidney Injury ◽  
Tubular Cell ◽  
Wild Type ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Proximal Tubular

Tubular cell necrosis is a key histological feature of acute kidney injury (AKI). Necroptosis is a type of programed necrosis, which is executed by mixed lineage kinase domain-like protein (MLKL) upon its binding to the plasma membrane. Emerging evidence indicates that necroptosis plays a critical role in the development of AKI. However, it is unclear whether renal tubular cells undergo necroptosis in vivo and how the necroptotic pathway is regulated during AKI. Repulsive guidance molecule (RGM)-b is a member of the RGM family. Our previous study demonstrated that RGMb is highly expressed in kidney tubular epithelial cells, but its biological role in the kidney has not been well characterized. In the present study, we found that RGMb reduced membrane-associated MLKL levels and inhibited necroptosis in cultured cells. During ischemia/reperfusion injury (IRI) or oxalate nephropathy, MLKL was induced to express on the apical membrane of proximal tubular (PT) cells. Specific knockout of Rgmb in tubular cells (Rgmb cKO) increased MLKL expression at the apical membrane of PT cells and induced more tubular cell death and more severe renal dysfunction compared with wild-type mice. Treatment with the necroptosis inhibitor Necrostatin-1 or GSK′963 reduced MLKL expression on the apical membrane of PT cells and ameliorated renal function impairment after IRI in both wild-type and Rgmb cKO mice. Taken together, our results suggest that proximal tubular cell necroptosis plays an important role in AKI, and that RGMb protects against AKI by inhibiting MLKL membrane association and necroptosis in proximal tubular cells.

scholarly journals AT1 and AT2 receptors modulate renal tubular cell necroptosis in angiotensin II-infused renal injury mice

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yongjun Zhu ◽  
Hongwang Cui ◽  
Jie Lv ◽  
Haiqin Liang ◽  
Yanping Zheng ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Renal Injury ◽  
Critical Role ◽  
Kidney Injury ◽  
Renin Angiotensin System ◽  
Tubular Cell ◽  
Tubular Damage ◽  
Renal Tubular Cell ◽  
Ang Ii ◽  
Renal Tubular

AbstractAbnormal renin-angiotensin system (RAS) activation plays a critical role in the initiation and progression of chronic kidney disease (CKD) by directly mediating renal tubular cell apoptosis. Our previous study showed that necroptosis may play a more important role than apoptosis in mediating renal tubular cell loss in chronic renal injury rats, but the mechanism involved remains unknown. Here, we investigate whether blocking the angiotensin II type 1 receptor (AT1R) and/or angiotensin II type 2 receptor (AT2R) beneficially alleviates renal tubular cell necroptosis and chronic kidney injury. In an angiotensin II (Ang II)-induced renal injury mouse model, we found that blocking AT1R and AT2R effectively mitigates Ang II-induced increases in necroptotic tubular epithelial cell percentages, necroptosis-related RIP3 and MLKL protein expression, serum creatinine and blood urea nitrogen levels, and tubular damage scores. Furthermore, inhibition of AT1R and AT2R diminishes Ang II-induced necroptosis in HK-2 cells and the AT2 agonist CGP42112A increases the percentage of necroptotic HK-2 cells. In addition, the current study also demonstrates that Losartan and PD123319 effectively mitigated the Ang II-induced increases in Fas and FasL signaling molecule expression. Importantly, disruption of FasL significantly suppressed Ang II-induced increases in necroptotic HK-2 cell percentages, and necroptosis-related proteins. These results suggest that Fas and FasL, as subsequent signaling molecules of AT1R and AT2R, might involve in Ang II-induced necroptosis. Taken together, our results suggest that Ang II-induced necroptosis of renal tubular cell might be involved both AT1R and AT2R and the subsequent expression of Fas, FasL signaling. Thus, AT1R and AT2R might function as critical mediators.

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