scholarly journals Palmitate aggravates proteinuria-induced cell death and inflammation via CD36-inflammasome axis in the proximal tubular cells of obese mice

2018 ◽  
Vol 315 (6) ◽  
pp. F1720-F1731 ◽  
Author(s):  
Lung-Chih Li ◽  
Jenq-Lin Yang ◽  
Wen-Chin Lee ◽  
Jin-Bor Chen ◽  
Chien-Te Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Tubular Injury ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Caspase 1 ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Nlrp3 Inflammasomes

High levels of serum free fatty acids (FFAs) and proteinuria have been implicated in the pathogenesis of obesity-related nephropathy. CD36, a class B scavenger receptor, is highly expressed in the renal proximal tubules and mediates FFA uptake. It is not clear whether FFA- and proteinuria-mediated CD36 activation coordinates NLRP3 inflammasomes to induce renal tubular injury and inflammation. In this study, we investigated the roles of CD36 and NLRP3 inflammasomes in FFA-induced renal injury in high-fat diet (HFD)-induced obesity. HFD-fed C57BL/6 mice and palmitate-treated HK2 renal tubular cells were used as in vivo and in vitro models. Immunohistochemical staining showed that CD36, IL-1β, and IL-18 levels increased progressively in the kidneys of HFD-fed mice. Sulfo- N-succinimidyl oleate (SSO), a CD36 inhibitor, attenuated the HFD-induced upregulation of NLRP3, IL-1β, and IL-18 and suppressed the colocalization of NLRP3 and ASC in renal tubular cells. In vitro, SSO abolished the palmitate-induced activation of IL-1β, IL-18, and caspase-1 in HK2 proximal tubular cells. Furthermore, treatment with SSO and the knockdown of caspase-1 expression by siRNA both inhibited palmitate-induced cell death and apoptosis in HK2 cells. Collectively, palmitate causes renal tubular inflammation, cell death, and apoptosis via the CD36/NLRP3/caspase-1 axis, which may explain, at least in part, the mechanism underlying FFA-related renal tubular injury. The blockade of CD36-induced cellular processes is therefore a promising strategy for treating obesity-related nephropathy.

scholarly journals The exosomes derived from urine of premature infants target MAPK8 via miR-30a-5p to protect cisplatin-induced acute kidney injury in mice

2021 ◽  
Author(s):  
Mingming Ma ◽  
Qiao Luo ◽  
Lijing Fan ◽  
Weilong Li ◽  
Qiang Li ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Premature Infants ◽  
Target Genes ◽  
Kidney Injury ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Hk2 Cells

Aim: Acute kidney injury (AKI), a global public health issue, not only causes millions of deaths every year, but is also a susceptible factor for chronic kidney disease (CKD). Nephrotoxic drugs are an important cause of AKI. There is still a lack of effective and satisfactory prevention method in clinical practice. This study investigated the protective effect of the exosomes derived from urine of premature infants on cisplatin-induced acute kidney injury. Methods: Isolation of exosomes from fresh urine of premature infants: The characteristics of exosomes were determined by flow cytometry, transmission electron microscopy and Western blotting. A C57BL/6 mice model of cisplatin-induced acute kidney injury was established. The mice in the experimental group were given 100ug exosomes dissolved in 200ul solution. The mice in the control group were given normal saline (200ul). These treatments were performed 24 hours after AKI was induced by intraperitoneal injection of cisplatin. To evaluate renal function, blood was drawn 24 hours after AKI model was established and serum creatinine (sCr) was measured. The mice were euthanized 72 hours after exosome treatment. The kidneys were collected for pathological examination, RNA and protein extraction, and the evaluation of renal tubular damage and apoptosis. In the in-vitro experiment, human renal cortex/proximal tubular cells (HK2) was induced by cisplatin to assess the protective ability of the exosomes derived from urine of premature infants. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western Blotting were used to evaluate the effect of exosomes treatment on the apoptosis of HK2 cells induced by cisplatin. Exosome microRNA sequencing technology and bioinformatics analysis method were applied to investigate the miRNAs enriched in exosomes and their target genes. The dual luciferase gene reporter system was used to detect the interaction of target genes. Results: Treatment of exosomes derived from urine of premature infants could decrease the level of serum creatinine and the apoptosis of renal tubular cell, inhibit the infiltration of inflammatory cell, protect mice from acute kidney injury induced by cisplatin and reduce mortality. In addition, miR-30a-5p was the most abundant miRNA in the exosomes derived from urine of premature infants. It protected HK2 cells from cisplatin-induced apoptosis by targeting and down-regulating the 3'UTR of mitogen-activated protein kinases (MAPK8) mRNA. Conclusions: According to our results, the exosomes derived from urine of premature infants alleviated cisplatin-induced acute kidney injury in mice and inhibited the apoptosis of human proximal tubular cells (HK2) induced by cisplatin in vitro. MiR-30a-5p in exosomes inhibited cisplatin-induced MAPK activation, ameliorated apoptosis, and protected renal function. The exosomes derived from urine of premature infants provided a promising acellular therapy for AKI.

scholarly journals Stress granules are formed in renal proximal tubular cells during metabolic stress and ischemic injury for cell survival

2019 ◽  
Vol 317 (1) ◽  
pp. F116-F123 ◽  
Author(s):  
Shixuan Wang ◽  
Sang-Ho Kwon ◽  
Yunchao Su ◽  
Zheng Dong
Keyword(s):  
Rna Binding ◽  
Ischemia Reperfusion ◽  
Metabolic Stress ◽  
Stress Granules ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Short Period ◽  
Proximal Tubular ◽  
Renal Tubular

Stress granules (SGs) are a type of cytoplasmic structures formed in eukaryotic cells upon cell stress, which mainly contain RNA-binding proteins and RNAs. The formation of SGs is generally regarded as a mechanism for cells to survive a harsh insult. However, little is known about SG formation and function in kidneys. To address this, we applied different kinds of stressors to cultured proximal tubular cells as well as a short period of ischemia-reperfusion to mouse kidneys. It was found that glycolytic inhibitors such as 2-deoxy-d-glucose and 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one induced SG formation within 30 min in these cells. Similarly, SGs were induced by inhibitors of mitochondrial respiration such as sodium azide and CCCP. Renal ischemia-reperfusion induced SG formation in the cells of proximal tubules. To test the role of SGs, we stably knocked down G3bp1, a SG core protein, in renal tubular cells by shRNA viral transduction. As expected, knockdown of G3bp1 largely disrupted the assembly of SGs. After azide or cisplatin treatment, more dead cells were found in knockdown cells compared with controls, accompanied by increases in cleaved/active caspase-3. Reintroduction of exogenous G3bp1 into knockdown cells could rescue the cell death phenotype. Taken together, our data provide the first evidence of SG formation in renal tubular cells during metabolic stress and acute kidney injury. SGs are formed to protect proximal tubular cells under these conditions. Modulation of SG biogenesis may provide a novel approach to lessen the severity of renal diseases.

scholarly journals Methylation pattern of urinary DNA as a marker of kidney function decline in diabetes

2020 ◽  
Vol 8 (1) ◽  
pp. e001501
Author(s):  
Takeshi Marumo ◽  
Junichi Hoshino ◽  
Wakako Kawarazaki ◽  
Mitsuhiro Nishimoto ◽  
Nobuhiro Ayuzawa ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Kidney Function ◽  
Tubular Injury ◽  
Proximal Tubular Cells ◽  
Urine Sediment ◽  
Tubular Cells ◽  
Patients With Diabetes ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Methylation Patterns

IntroductionRenal tubular injury contributes to the decline in kidney function in patients with diabetes. Cell type-specific DNA methylation patterns have been used to calculate proportions of particular cell types. In this study, we developed a method to detect renal tubular injury in patients with diabetes by detecting exfoliated tubular cells shed into the urine based on tubular cell-specific DNA methylation patterns.Research design and methodsWe identified DNA methylation patterns specific for human renal proximal tubular cells through compartment-specific methylome analysis. We next determined the methylation levels of proximal tubule-specific loci in urine sediment of patients with diabetes and analyzed correlation with clinical variables.ResultsWe identified genomic loci in SMTNL2 and G6PC to be selectively unmethylated in human proximal tubular cells. The methylation levels of SMTNL2 and G6PC in urine sediment, deemed to reflect the proportion of exfoliated proximal tubular cells due to injury, correlated well with each other. Methylation levels of SMTNL2 in urine sediment significantly correlated with the annual decline in estimated glomerular filtration rate. Moreover, addition of urinary SMTNL2 methylation to a model containing known risk factors significantly improved discrimination of patients with diabetes with faster estimated glomerular filtration rate decline.ConclusionsThis study demonstrates that patients with diabetes with continual loss in kidney function may be stratified by a specific DNA methylation signature through epigenetic urinalysis and provides further evidence at the level of exfoliated cells in the urine that injury of proximal tubular cells may contribute to pathogenesis of diabetic kidney disease.

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.

In vivo and in vitro detachment of proximal tubular cells and F-actin damage: consequences for renal function

1994 ◽  
Vol 267 (5) ◽  
pp. F888-F899 ◽  
Author(s):  
B. Van de Water ◽  
J. J. Jaspers ◽  
D. H. Maasdam ◽  
G. J. Mulder ◽  
J. F. Nagelkerke
Keyword(s):  
Cell Death ◽  
Focal Adhesions ◽  
Free Calcium ◽  
Cell Detachment ◽  
Proximal Tubular Cells ◽  
Acetoxymethyl Ester ◽  
Tubular Cells ◽  
Proximal Tubular

We investigated the relationship between F-actin damage and cell detachment using nephrotoxic L-cysteine S-conjugates. In vivo S-(1,2-dichlorovinyl)-L-cysteine (DCVC) induced loss of F-actin in the S3 segment of the proximal tubule in the outer stripe of the outer medulla, which was associated with loss of the brush border and loss of cells from the basement membrane. In vitro DCVC caused the detachment of primary cultured rat renal proximal tubular cells (PTC), which was clearly associated with F-actin damage. Disorganization of F-actin correlated with an increase in cellular levels of G-actin, indicating depolymerization of F-actin. Cell detachment was preceded by a complete loss of the alpha-actinin binding protein talin from the focal adhesions, which was directly associated with F-actin disorganization. Inhibition of formation of highly reactive metabolites from L-cysteine S-conjugates by L-cysteine-S-conjugate beta-lyase completely prevented both F-actin damage and cell detachment by DCVC. Although inhibition of DCVC-induced lipid peroxidation and reduction of intracellular free calcium by N,N'-diphenyl-p-phenylenediamine and the acetoxymethyl ester of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, respectively, clearly prevented cell death, no protection was observed against the DCVC-induced F-actin disorganization, talin redistribution, and cell detachment. Also, F-actin damage was unrelated to changes in the energy status of the PTC, since cellular ATP content was unaffected. The data clearly demonstrate a close relationship between F-actin damage, disturbances of focal adhesions, and cell detachment. In addition, different molecular pathways are involved in the cell detachment caused by F-actin disorganization and initiation of cell death.

The Use of Porcine Proximal Tubular Cells for Studying Nephrotoxicity In Vitro: The Role of Oxidative Stress in Cisplatin-induced Cell Death

1996 ◽  
Vol 24 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Marieke Kruidering ◽  
Bob van de Water ◽  
Emile de Heer ◽  
Gerard J. Mulder ◽  
J. Fred Nagelkerke
Keyword(s):  
Cell Death ◽  
Complex I ◽  
Proximal Tubular Cells ◽  
Complex Ii ◽  
Tubular Cells ◽  
Dependent Inhibition ◽  
Proximal Tubular ◽  
Ros Formation ◽  
Dose Dependent Inhibition

The effects of a widely used antitumour drug, cisplatin, on freshly isolated porcine proximal tubular cells (PPTC) in suspension were investigated. Incubation of the PPTC with 5-500μM cisplatin resulted in a decrease in mitochondrial membrane potential (MMP) and in cell death. In addition, the formation of reactive oxygen species (ROS) was observed within 20 minutes. Prevention of ROS formation with the antioxidants diphenyl- p-phenylene-diamine (DPPD) or desferrioxamine had no effect on the cisplatin-induced effects on MMP and cell death, implying that cisplatin-induced ROS formation is not a cause of cell death. In order to investigate whether the ROS formation was related to mitochondrial damage, we determined the effects of cisplatin on the enzymatic activities of NADP:ubiquinone reductase (Complex I) and succinate:ubiquinone reductase (Complex II) of the respiratory chain. Exposure of the PPTC to cisplatin resulted in a time-dependent and dose-dependent inhibition of the activities of both Complex I and Complex II. The inhibition of these activities and the depletion of ATP could not be prevented by the antioxidants, indicating that these effects are not a consequence of ROS formation. We propose that damage to the mitochondria could be a key event in cisplatin-induced cell death.

scholarly journals Atrasentan increased the expression of klotho by mediating miR-199b-5p and prevented renal tubular injury in diabetic nephropathy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Wen-Ling Kang ◽  
Gao-Si Xu
Keyword(s):  
Diabetic Nephropathy ◽  
High Glucose ◽  
Tubular Injury ◽  
Mice Model ◽  
Renal Tubular Cells ◽  
Proximal Tubular ◽  
Renal Proximal Tubular ◽  
Renal Tubular

Abstract Atrasentan is a promising therapy for treating diabetic nephropathy (DN). Here we evaluated whether atrasentan down-regulated the miR-199b-5p expression, thereby increasing klotho and preventing renal tubular injury in DN. One-hundred patients with type 2 diabetes mellitus (T2DM) and 40 healthy subjects were included. A DN mice model was established by an injection of streptozotocin (STZ). Human renal proximal tubular epithelial HK-2 cells were exposed to high glucose (20 mmol/L). Treated the mice and HK-2 cells with atrasentan and we then investigated whether and how miR-199b-5p and Klotho were involved in preventing renal tubular injury in DN. In patients, the serum miR-199b-5p level increased and the klotho concentration decreased in accordance with elevated albuminuria. Atrasentan down-regulated miR-199b-5p and up-regulated klotho of the DN mice and HK-2 cells exposed to high glucose. High glucose promoted the binding of histone H3 to the miR-199b-5p promoter and atrasentan canceled this effect. MiR-199b-5p targeted the 3′ UTR of klotho. Overexpression of miR-199b-5p canceled the effects of atrasentan on klotho expression and apoptosis of renal tubular cells in both in vivo and in vitro. The increased serum klotho, mediated by miR-199b-5p, is a possible mechanism by which atrasentan prevents renal tubular injury in DN.

scholarly journals Compound C Protects Against Cisplatin-Induced Nephrotoxicity Through Pleiotropic Effects

2020 ◽  
Vol 11 ◽  
Author(s):  
Fanghua Li ◽  
Anbang Sun ◽  
Genyang Cheng ◽  
Dong Liu ◽  
Jing Xiao ◽  
...  
Keyword(s):  
Pleiotropic Effects ◽  
Protective Effects ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Compound C ◽  
Proximal Tubular ◽  
Renal Tubular ◽  
Induced Apoptosis

AICAR (Acadesine/AICA riboside) as an activator of AMPK, can protect renal tubular cells from cisplatin induced apoptosis. But in our experiment, the dorsomorphin (compound C, an inhibitor of AMPK) also significantly reduced cisplatin induced renal tubular cells apoptosis. Accordingly, we tested whether compound C can protect cisplatin-induced nephrotoxicity and the specific mechanism. Here, we treated Boston University mouse proximal tubular cells (BUMPT-306) with cisplatin and/or different dosages of AICAR (Acadesine/AICA riboside) or compound C to confirm the effect of AICAR and compound C in vitro. The AMPK-siRNA treated cells to evaluate whether the protective effect of compound C was through inhibiting AMPK. Male C57BL/6 mice were used to verify the effect of compound C in vivo. Both compound C and AICAR can reduce renal tubular cells apoptosis in dose-dependent manners, and compound C decreased serum creatinine and renal tubular injury induced by cisplatin. Mechanistically, compound C inhibited P53, CHOP and p-IREα during cisplatin treatment. Our results demonstrated that compound C inhibited AMPK, but the renal protective effects of compound C were not through AMPK. Instead, compound C protected cisplatin nephrotoxicity by inhibiting P53 and endoplasmic reticulum (ER) stress. Therefore, compound C may protect against cisplatin-induced nephrotoxicity through pleiotropic effects.

scholarly journals Empagliflozin Ameliorates Free Fatty Acid Induced-Lipotoxicity in Renal Proximal Tubular Cells via the PPARγ/CD36 Pathway in Obese Mice

2021 ◽  
Vol 22 (22) ◽  
pp. 12408
Author(s):  
Chiang-Chi Huang ◽  
Chia-An Chou ◽  
Wei-Yu Chen ◽  
Jenq-Lin Yang ◽  
Wen-Chin Lee ◽  
...  
Keyword(s):  
Body Weight Gain ◽  
Specific Inhibitor ◽  
Proximal Tubular Cells ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Cd36 Expression ◽  
Proximal Tubular ◽  
Renal Proximal Tubular Cells ◽  
Renal Proximal Tubular ◽  
Renal Tubular

High serum levels of free fatty acids (FFAs) could contribute to obesity-induced nephropathy. CD36, a class B scavenger receptor, is a major receptor mediating FFA uptake in renal proximal tubular cells. Empagliflozin, a new anti-diabetic agent, is a specific inhibitor of sodium-glucose co-transporter 2 channels presented on renal proximal tubular cells and inhibits glucose reabsorption. In addition, empagliflozin has shown renoprotective effects. However, the mechanism through which empagliflozin regulates CD36 expression and attenuates FFA-induced lipotoxicity remains unclear. Herein, we aimed to elucidate the crosstalk between empagliflozin and CD36 in FFA-induced renal injury. C57BL/6 mice fed a high-fat diet (HFD) and palmitic acid-treated HK-2 renal tubular cells were used for in vivo and in vitro assessments. Empagliflozin attenuated HFD-induced body weight gain, insulin resistance, and inflammation in mice. In HFD-fed mice, CD36 was upregulated in the tubular area of the kidney, whereas empagliflozin attenuated CD36 expression. Furthermore, empagliflozin downregulated the expression of peroxisome proliferator-activated receptor (PPAR)-γ. Treatment with a PPARγ inhibitor (GW9662) did not further decrease PPARγ expression, whereas a PPARγ antagonist reversed this effect; this suggested that empagliflozin may, at least partly, decrease CD36 by modulating PPARγ. In conclusion, empagliflozin can ameliorate FFA-induced renal tubular injury via the PPARγ/CD36 pathway.

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