scholarly journals Update on Mechanisms of Renal Tubule Injury Caused by Advanced Glycation End Products

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hong Sun ◽  
Yang Yuan ◽  
Zilin Sun
Keyword(s):  
Advanced Glycation End Products ◽  
Lipid Accumulation ◽  
Cholesterol Efflux ◽  
Cholesterol Synthesis ◽  
Renal Tubule ◽  
Foam Cell Formation ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products ◽  
Renal Tubular

Diabetic nephropathy (DN) caused by advanced glycation end products (AGEs) may be associated with lipid accumulation in the kidneys. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML, a member of the AGEs family) increases lipid accumulation in a human renal tubular epithelial cell line (HK-2) via increasing cholesterol synthesis and uptake and reducing cholesterol efflux through endoplasmic reticulum stress (ERS). Our results showed that CML disrupts cholesterol metabolism in HK-2 cells by activating sterol regulatory element-binding protein 2 (SREBP-2) and liver X receptor (LXR), followed by an increase in 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) mediated cholesterol synthesis and low density lipoprotein receptor (LDLr) mediated cholesterol uptake and a reduction in ATP-binding cassette transporter A1 (ABCA1) mediated cholesterol efflux, ultimately causing lipid accumulation in HK-2 cells. All of these responses could be suppressed by an ERS inhibitor, which suggests that CML causes lipid accumulation in renal tubule cells through ERS and that the inhibition of ERS is a potential novel approach to treating CML-induced renal tubular foam cell formation.

Advanced glycation end products (AGEs) increase human mesangial foam cell formation by increasing Golgi SCAP glycosylation in vitro

2011 ◽  
Vol 301 (1) ◽  
pp. F236-F243 ◽  
Author(s):  
Yang Yuan ◽  
Lei Zhao ◽  
Yaxi Chen ◽  
John F. Moorhead ◽  
Zac Varghese ◽  
...  
Keyword(s):  
Advanced Glycation End Products ◽  
Lipid Accumulation ◽  
Foam Cell ◽  
Cell Formation ◽  
Protein Glycosylation ◽  
Foam Cell Formation ◽  
Advanced Glycation ◽  
Processing Enzymes ◽  
Glycation End Products ◽  
End Products

Advanced glycation end products (AGEs) is one of the causative factors of diabetic nephropathy, which is associated with lipid accumulation in glomeruli. This study was designed to investigate whether Nε-(carboxymethyl) lysine (CML; a member of the AGEs family) increases lipid accumulation by impairing the function of sterol-regulatory element binding protein (SREBP) cleavage-activating protein (SCAP) in human mesangial cells (HMCs). Intracellular cholesterol content was assessed by Oil Red O staining and quantitative assay. The expression of molecules controlling cholesterol homeostasis was examined using real-time quantitative RT-PCR and Western blotting. The activity of Golgi-processing enzymes was determined using enzyme-based methods, and the translocation of SCAP from the endoplasmic reticulum (ER) to the Golgi was detected by confocal microscopy. CML increased cholesterol accumulation in HMCs. Exposure to CML increased expression and abnormal translocation of SCAP from the ER to the Golgi even in the presence of a high concentration of LDL. The increased SCAP translocation carried more SREBP-2 to the Golgi for activation by proteolytic cleavages, enhancing transcription of 3-hydroxy-3-methylclutaryl-CoA reductase and the LDL receptor. CML increased Golgi mannosidase activity, which may enhance glycosylation of SCAP. This prolonged the half-life and enhanced recycling of SCAP between the ER and the Golgi. The effects of CML were blocked by inhibitors of Golgi mannosidases. AGEs (CML) increased lipid synthesis and uptake, thereby causing foam cell formation via increasing transcription and protein glycosylation of SCAP in HMCs. These data imply that inhibitors of Golgi-processing enzymes might have a potential renoprotective role in prevention of mesangial foam cell formation.

scholarly journals Soluble receptor for advanced glycation end products protects from ischemia- and reperfusion-induced acute kidney injury

Biology Open ◽  
2021 ◽  
Author(s):  
Taro Miyagawa ◽  
Yasunori Iwata ◽  
Megumi Oshima ◽  
Hisayuki Ogura ◽  
Koichi Sato ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Advanced Glycation End Products ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Tubular Damage ◽  
Advanced Glycation ◽  
Renal Tubular Damage ◽  
Glycation End Products ◽  
End Products ◽  
Renal Tubular

The full-length receptor for advanced glycation end products (RAGE) is a multiligand pattern recognition receptor. High-mobility group box 1 (HMGB1) is a RAGE ligand of damage-associated molecular patterns that elicits inflammatory reactions. The shedded isoform of RAGE and endogenous secretory RAGE (esRAGE), a splice variant, are soluble isoforms (sRAGE) that act as organ-protective decoys. However, the pathophysiologic roles of RAGE/sRAGE in acute kidney injury (AKI) remain unclear. We found that AKI was more severe, with enhanced renal tubular damage, macrophage infiltration, and fibrosis, in mice lacking both RAGE and sRAGE than in wild-type control mice. Using murine tubular epithelial cells (TECs), we demonstrated that hypoxia upregulated messenger RNA (mRNA) expression of HMGB1 and tumor necrosis factor α (TNF-α), whereas RAGE and esRAGE expressions were paradoxically decreased. Moreover, the addition of recombinant sRAGE canceled hypoxia-induced inflammation and promoted cell viability in cultured TECs. sRAGE administration prevented renal tubular damage in models of ischemia/reperfusion-induced AKI and of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. These results suggest that sRAGE is a novel therapeutic option for AKI.

scholarly journals Soluble Receptor for Advanced Glycation End Products: A Protective Molecule against Intramyocardial Lipid Accumulation in Obese Zucker Rats?

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Elena Dozio ◽  
Elena Vianello ◽  
Francesco Bandera ◽  
Erika Longhi ◽  
Stefano Brizzola ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Advanced Glycation End Products ◽  
Lipid Accumulation ◽  
Soluble Form ◽  
Zucker Rats ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products ◽  
Rage Expression

Most of the obesity-related complications are due to ectopic fat accumulation. Recently, the activation of the cell-surface receptor for advanced glycation end products (RAGE) has been associated with lipid accumulation in different organs. Nevertheless, the role of RAGE and sRAGE, the soluble form that prevents ligands to activate RAGE, in intramyocardial lipid accumulation is presently unknown. To this aim, we analyzed whether, in obesity, intramyocardial lipid accumulation and lipid metabolism-related transcriptome are related to RAGE and sRAGE. Heart and serum samples were collected from 10 lean (L) and 10 obese (OB) Zucker rats. Oil red staining was used to detect lipids on frozen heart sections. The lipid metabolism-related transcriptome (84 genes) was analyzed by a specific PCR array. Heart RAGE expression was explored by real-time RT-PCR and Western blot analyses. Serum levels of sRAGE (total and endogenous secretory form (esRAGE)) were quantified by ELISA. Genes promoting fatty acid transport, activation, and oxidation in mitochondria/peroxisomes were upregulated in OB hearts. Intramyocardial lipid content did not differ between OB and L rats, as well as RAGE expression. A slight increase in epicardial adipose tissue was observed in OB hearts. Total sRAGE and esRAGE concentrations were significantly higher in OB rats. sRAGE may protect against obesity-induced intramyocardial lipid accumulation by preventing RAGE hyperexpression, therefore allowing lipids to be metabolized. EAT also played a protective role by working as a buffering system that protects the myocardium against exposure to excessively high levels of fatty acids. These observations reinforce the potential role of RAGE pathway as an interesting therapeutic target for obesity-related complications, at least at the cardiovascular level.

HMGB1 Enhances the AGE-Induced Expression of CTGF and TGF-β via RAGE-Dependent Signaling in Renal Tubular Epithelial Cells

2015 ◽  
Vol 41 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Meichu Cheng ◽  
Hong Liu ◽  
Dongshan Zhang ◽  
Yinghong Liu ◽  
Chang Wang ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Advanced Glycation End Products ◽  
Tubular Epithelial Cells ◽  
Advanced Glycation ◽  
Induced Expression ◽  
Mesenchymal Transition ◽  
Glycation End Products ◽  
End Products ◽  
Renal Tubular

Background/Aims: Advanced glycation end products (AGEs) induce epithelial mesenchymal transition (EMT) in renal proximal tubular epithelial cells (PTECs) by promoting the two EMT regulators, transforming growth factor beta (TGF-β) and connective tissue growth factor (CTGF). However, the exact signaling mechanism remains largely unclear. Methods: We investigated the promotion to high mobility group box 1 (HMGB1) in renal tubular epithelial HK-2 cells by AGE-BSA with quantitative PCR and western blot assay, and then determined the regulatory role of HMGB1 in the AGE-BSA-induced CTGF and TGF-β. In addition, the dependence of the receptor of advanced glycation end products (RAGE) was also examined in the CTGF and TGF-β promotion by AGEs and HMGB1 in HK-2 cells using the RNAi method. Results: It was demonstrated that AGEs induced translocation and release of HMGB1 from tubular epithelial HK-2 cells, and the released HMGB1 enhanced the promotion to CTGF and TGF-β by AGEs in HK-2 cells. On the other side, the HMGB1 knockdown by siRNA attenuated the AGE-BSA-induced expression of TGF-β. Moreover, the CTGF and TGF-β promotion in HK-2 cells by AGEs and HMGB1 was RAGE-dependent. Conclusion: Our results indicated that AGEs induced HMGB-1 and promoted the CTGF and TGF-β in renal epithelial HK-2 cells RAGE-dependently. And there was a synergism between AGEs and HMGB1 in the RAGE signaling activation. The in vitro data suggested that the AGE-RAGE and HMGB-1-RAGE signaling might play an important role in the promotion of CTGF and TGF-β in the renal fibrosis process of diabetic nephropathy.

Sign in / Sign up

Export Citation Format

Share Document