Receptor for advanced glycation endproducts (RAGE) is a multi-ligand receptor that is able to bind several different ligands, including advanced glycation endproducts, high-mobility group protein (B)1 (HMGB1), S-100 calcium-binding protein, amyloid-beta-protein, Mac-1, and phosphatidylserine. Its interaction is engaged in critical cellular processes, such as inflammation, proliferation, apoptosis, autophagy, and migration, and dysregulation of RAGE and its ligands leads to the development of numerous human diseases. In this review, we summarize the signaling pathways regulated by RAGE and its ligands identified up to date and demonstrate the effects of hyper-activation of RAGE signals on human diseases, focused mainly on renal disorders. Finally, we propose that RAGE and its ligands are the potential targets for the diagnosis, monitoring, and treatment of numerous renal diseases.
Apoptosis ; Autophagy ; Biomarkers* ; Diagnosis* ; Humans* ; Inflammation ; Kidney Diseases ; Ligands* ; Rage* ; Signal Transduction ; Advanced Glycosylation End Product-Specific Receptor

BACKGROUND AND PURPOSE: The receptor for advanced glycation end products (RAGE) may contribute to the development of diabetic neuropathy. To assess its relevance in humans, this study examined the expression of RAGE in the skin biopsy samples of patients with diabetes mellitus, and investigated its correlation with intraepidermal nerve-fiber density (IENFD) and clinical measures of neuropathy severity. METHODS: Forty-four patients who either had type 2 diabetes or were prediabetes underwent clinical evaluation and a 3-mm skin punch biopsy. The clinical severity of their neuropathy was assessed using the Michigan Diabetic Neuropathy Score. IENFD was measured along with immunohistochemical staining for RAGE in 29 skin biopsy samples. The expression of RAGE was also quantified by real-time reverse-transcription PCR in the remaining 15 patients. RESULTS: RAGE was localized mostly in the dermal and subcutaneous vascular endothelia. The staining was more intense in patients with a lower IENFD (p=0.004). The quantity of RAGE mRNA was significantly higher in patients with severe neuropathy than in those with no or mild neuropathy (p=0.003). The up-regulation of RAGE was related to dyslipidemia and diabetic nephropathy. There was a trend toward decreased sural nerve action-potential amplitude and slowed peroneal motor-nerve conduction with increasing RAGE expression. CONCLUSIONS: The findings of this study demonstrate up-regulation of RAGE in skin biopsy samples from patients with diabetic neuropathy, supporting a pathogenic role of RAGE in the development of diabetic neuropathy.
Biopsy* ; Diabetes Mellitus ; Diabetic Nephropathies ; Diabetic Neuropathies* ; Dyslipidemias ; Glycosylation End Products, Advanced* ; Humans ; Michigan ; Polymerase Chain Reaction ; Prediabetic State ; Rage ; RNA, Messenger ; Skin* ; Sural Nerve ; Up-Regulation* ; Advanced Glycosylation End Product-Specific Receptor

Reactive oxygen species (ROS) is an oxidative stress to which cells respond by activating various defense mechanisms or cell death. Autophagy associated with oxidative stress response is a process to degrade and recycle macro-molecule as well as organelles in eukaryotic cells. HMGB1, a ubiquitous nuclear protein, is actively released in eukaryotic cells under oxidative stress. HMGB1 plays an important role as regulator of autophagy in nuclear, cytosolic and extracellular level. Nuclear HMGB1 regulates the expression of heat shock protein beta-1 (HSPB1), which is critical for dynamic intracellular trafficking during autophagy and mitophagy. Cytoplasmic HMGB1 can bind to a beclin 1 by the intramolecular disulfide bridge using cysteine 23 and 45, which dissociates its inhibitory partner Bcl-2 and induces autophagy. Extracellular HMGB1 binds to receptor for advanced glycation endproducts (RAGE) which inhibits mammalian target of rapamycin (mTOR) and then promotes the formation of the belin1-Ptdlns3KC3 complex. Furthermore, endogenous HMGB1 is an intrinsic regulator of autophagy, and it enhances chemoresistance in diverse cancer cells. Here, we review recent reports suggesting a novel mechanism of diverse cancer cell resistance to therapy facilitated by HMGB1-mediated autophagy.
Advanced Glycosylation End Product-Specific Receptor ; Autophagy ; Cell Death ; Cysteine ; Cytoplasm ; Cytosol ; Defense Mechanisms ; Drug Resistance ; Eukaryotic Cells ; HMGB1 Protein ; HSP27 Heat-Shock Proteins ; Mitochondrial Degradation ; Nuclear Proteins ; Organelles ; Oxidative Stress ; Reactive Oxygen Species ; Receptors, Immunologic ; Sirolimus

The receptor for advanced glycation end products (RAGE) has been reported to have a pivotal role in the pathogenesis of Alzheimer's disease (AD). This study investigated RAGE levels in the hippocampus and cortex of a triple transgenic mouse model of AD (3xTg-AD) using western blotting and immunohistochemical double-labeling to assess cellular localization. Analysis of western blots showed that there were no differences in the hippocampal and cortical RAGE levels in 10-month-old adult 3xTg-AD mice, but significant increases in RAGE expression were found in the 22- to 24-month-old aged 3xTg-AD mice compared with those of age-matched controls. RAGE-positive immunoreactivity was observed primarily in neurons of aged 3xTg-AD mice with very little labeling in non-neuronal cells, with the notable exception of RAGE presence in astrocytes in the hippocampal area CA1. In addition, RAGE signals were co-localized with the intracellular amyloid precursor protein (APP)/amyloid beta (Abeta) but not with the extracellular APP/Abeta. In aged 3xTg-AD mice, expression of human tau was observed in the hippocampal area CA1 and co-localized with RAGE signals. The increased presence of RAGE in the 3xTg-AD animal model showing critical aspects of AD neuropathology indicates that RAGE may contribute to cellular dysfunction in the AD brain.
Advanced Glycosylation End Product-Specific Receptor ; Alzheimer Disease/genetics/*metabolism ; Amyloid beta-Peptides/metabolism ; Animals ; Astrocytes/*metabolism ; CA1 Region, Hippocampal/growth & development/metabolism/pathology ; Humans ; Mice ; Mice, Transgenic ; Neurons/*metabolism ; Receptors, Immunologic/genetics/*metabolism ; tau Proteins/genetics/metabolism

BACKGROUND: Advanced glycation end products (AGE) are independent risk factors in the development and progression of diabetic nephropathy. Receptor for AGE(RAGE) is considered the main receptor involved in AGE-induced cell activation. Galectin-3, another AGE receptor, has recently been found upregulated in mesangial cells(MC) cultured under high glucose and in diabetic rat kidneys. N epsilon(carboxymethyl)lysine(CML) is a well characterized AGE but its role in MC activation is unknown. The present study examined the effects of CML on MC proliferation and extracellular matrix(ECM) secretion. METHODS: Synchronized rat MC were stimulated with different concentrations of CML-bovine serum albumin(BSA), control BSA, and transforming growth factor-beta(TGF-beta) for up to 72 hours. Cell proliferation was measured by [3H]-thymidine incorporation. Fibronectin, TGF-beta, plasminogen activator inhibitor(PAI)-1 secreted into the media and RAGE and galectin-3 expression in MC were measured by Western blot analysis and ELISA. RESULTS: 1,000 micro /mL of CML-BSA decreased [3H]-thymidine incorporation by MC at 48 hours and 10 ng/mL TGF-beta at 24 and 48 hours. CML-BSA 100 and 1,000 micro /mL, control BSA 1,000 micro /mL, and TGF-beta 10 ng/mL increased fibronectin secretion at 48 hours. CML-BSA up to 1,000 micro /mL did not affect TGF-beta or PAI-1 secretion. TGF-beta 10 ng/mL, however, significantly increased PAI-1 secretion. Cultured MC expressed both RAGE and galectin-3. CML-BSA 100 micro /mL upregulated galectin-3 expression. CONCLUSION: CML-BSA decreased MC proliferation and increased fibronectin secretion, suggesting that CML may lead to ECM accumulation and glomerulosclerosis in diabetic animals. MC express RAGE and galectin-3 constitutively and CML-induced galectin-3 upregulation may have a role in AGE-induced MC activation.
Animals ; Blotting, Western ; Cell Proliferation ; Diabetic Nephropathies ; Enzyme-Linked Immunosorbent Assay ; Fibronectins ; Galectin 3 ; Glucose ; Glycosylation End Products, Advanced ; Kidney ; Mesangial Cells* ; Plasminogen Activator Inhibitor 1 ; Plasminogen Activators ; Rage ; Rats ; Risk Factors ; Transforming Growth Factor beta ; Up-Regulation ; Advanced Glycosylation End Product-Specific Receptor

PURPOSE: The high mobility group box 1 (HMGB1) protein has roles in apoptosis and immune responses by acting as a ligand for receptor for advanced glycation end products (RAGE), Toll-like receptors (TLRs), and triggering receptor expressed on myeloid cells 1. In particular, HMGB1/RAGE is involved in tumor metastasis by inducing matrix metalloproteinase 2 (MMP2) and MMP9 expression. We investigated the associations between genetic variations in HMGB1-related genes and disease-free survival (DFS) and overall survival (OS) in Korean female breast cancer patients. METHODS: A total of 2,027 patients in the Seoul Breast Cancer Study were included in the analysis. One hundred sixteen single nucleotide polymorphisms (SNPs) were extracted from eight genes. A multivariate Cox proportional hazards model was used to estimate the hazard ratio and 95% confidence interval (CI) of each SNP. The effects of the SNPs on breast cancer prognosis were assessed at cumulative levels with polygenic risk scores. RESULTS: The SNPs significantly associated with DFS were rs243867 (hazard ratio, 1.26; 95% CI, 1.05–1.50) and rs243842 (hazard ratio, 1.24; 95% CI, 1.03–1.50); both SNPs were in MMP2. The SNPs significantly associated with OS were rs243842 in MMP2 (hazard ratio, 1.33; 95% CI 1.03–1.71), rs4145277 in HMGB1 (hazard ratio, 1.29; 95% CI, 1.00–1.66), rs7656411 in TLR2 (hazard ratio, 0.76; 95% CI, 0.60–0.98), and rs7045953 in TLR4 (hazard ratio, 0.50; 95% CI, 0.29–0.84). The polygenic risk score results for the DFS and OS patients showed third tertile hazard ratios of 1.72 (95% CI, 1.27–2.34) and 2.75 (95% CI, 1.79–4.23), respectively, over their first tertile references. CONCLUSION: The results of the present study indicate that genetic polymorphisms in HMGB1-related genes are related to breast cancer prognosis in Korean women.
Advanced Glycosylation End Product-Specific Receptor ; Apoptosis ; Breast Neoplasms* ; Breast* ; Disease-Free Survival ; Female ; Genetic Predisposition to Disease* ; Genetic Variation ; HMGB1 Protein ; Humans ; Matrix Metalloproteinase 2 ; Myeloid Cells ; Neoplasm Metastasis ; Polymorphism, Genetic ; Polymorphism, Single Nucleotide ; Prognosis* ; Proportional Hazards Models ; Seoul ; Toll-Like Receptors