Levels Of Receptor For Advanced Glycation End-products Research Articles

Low bone turnover is associated with advanced glycation end-products, oxidative stress, and inflammation induced by type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) can lead to multiple complications. T2DM-related bone damage has been linked to abnormal bone turnover, but it cannot fully explain the mechanisms of T2DM bone disease. This study attempts to elucidate the underlying mechanisms of poor bone quality in T2DM. Hence, T2DM model was induced by a high-fat diet combined with a single streptozotocin injection in 7-week-old male SD rats. Osteoblasts derived from SD rats were cultured in high glucose to mimic hyperglycemia. Low bone turnover was observed in T2DM bone with elevated levels of advanced glycation end-products (AGEs) and receptor for AGEs (RAGE). Additionally, higher levels of oxidative stress and inflammatory factors were found in T2DM bone. AGEs content in bone was pairwise correlated with RAGE, hydrogen peroxide, and inflammatory factors. Serum levels of RAGE, oxidative stress, and inflammatory factors were higher in T2DM, while AGEs content tended to be lower. Besides, 35 differentially expressed metabolites were screened in T2DM serum. Osteoblasts exposed to high glucose displayed analogous abnormal changes in these biomarkers. Thus, low bone turnover in T2DM might be partially due to excess oxidative stress and inflammation induced by AGE-RAGE signaling. Furthermore, these biomarker levels in serum were mostly consistent with bone, demonstrating their possibility for predicting bone quality in T2DM.

The Gly82Ser polymorphism in the receptor for advanced glycation endproducts increases the risk for coronary events in the general population

The receptor for advanced glycation endproducts (RAGE) has pro-inflammatory and pro-atherogenic effects. Low plasma levels of soluble RAGE (sRAGE), a decoy receptor for RAGE ligands, have been associated with increased risk for major adverse coronary events (MACE) in the general population. We performed a genome-wide association study to identify genetic determinants of plasma sRAGE in 4338 individuals from the cardiovascular arm of the Malmö Diet and Cancer study (MDC-CV). Further, we explored the associations between these genetic variants, incident first-time MACE and mortality in 24,640 unrelated individuals of European ancestry from the MDC cohort. The minor alleles of four single nucleotide polymorphisms (SNPs): rs2070600, rs204993, rs116653040, and rs7306778 were independently associated with lower plasma sRAGE. The minor T (vs. C) allele of rs2070600 was associated with increased risk for MACE [HR 1.13 95% CI (1.02–1.25), P = 0.016]. Neither SNP was associated with mortality. This is the largest study to demonstrate a link between a genetic sRAGE determinant and CV risk. Only rs2070600, which enhances RAGE function by inducing a Gly82Ser polymorphism in the ligand-binding domain, was associated with MACE. The lack of associations with incident MACE for the other sRAGE-lowering SNPs suggests that this functional RAGE modification is central for the observed relationship.

Receptor for advanced glycation end products polymorphisms in coronary artery ectasia

BackgroundAlthough the implication of receptor of advanced glycation endproducts (RAGE) has been reported in coronary artery disease, its roles in coronary artery ectasia (CAE) have remained undetermined. Furthermore, the effect of RAGE polymorfisms were not well-defined in scope of soluble RAGE (sRAGE) levels. Thus, we aimed to investigate the influence of the functional polymorphisms of RAGE -374T > A (rs1800624) and G82S (rs2070600) in CAE development. MethodsThis prospective observational study was conducted in 2 groups selected of 2452 patients who underwent elective coronary angiography (CAG) for evaluation after positive noninvasive heart tests. Group-I included 98 patients with non-obstructive coronary artery disease and CAE, and Group-II (control) included 100 patients with normal coronary arteries. SNPs were genotyped by real-time PCR using Taqman® genotyping assay. Serum sRAGE and soluble lectin-like oxidized receptor-1 (sOLR1) were assayed by ELISA and serum lipids were measured enzymatically. ResultsThe frequencies of the RAGE -374A allele and -374AA genotype were significantly higher in CAE patients compared to controls (p < 0.001). sRAGE levels were not different between study groups, while sOLR1 levels were elevated in CAE (p = 0.004). In controls without systemic disease, -374A allele was associated with low sRAGE levels (p < 0.05), but this association was not significant in controls with HT. Similarly, sRAGE levels of CAE patients with both HT and T2DM were higher than those no systemic disease (p = 0.02). The -374A allele was also associated with younger patient age and higher platelet count in the CAE group in both total and subgroup analyses. In the correlation analyses, the -374A allele was also negatively correlated with age and positively correlated with Plt in all of these CAE groups. In the total CAE group, sRAGE levels also showed a positive correlation with age and a negative correlation with HDL-cholesterol levels. On the other hand, a negative correlation was observed between sRAGE and Plt in the total, hypertensive and no systemic disease control subgroups. Multivariate logistic regression analysis confirmed that the -374A allele (p < 0.001), hyperlipidemia (p < 0.05), and high sOLR1 level (p < 0.05) are risk factors for CAE. ROC curve analysis shows that RAGE -374A allele has AUC of 0.713 (sensitivity: 83.7 %, specificity: 59.0 %), which is higher than HLD (sensitivity: 59.2 %, specificity: 69.0 %), HT (sensitivity: 62.4 %, specificity: 61.1 %) and high sOLR1 level (≥0.67 ng/ml)) (sensitivity: 59.8 %, specificity: 58.5 %). ConclusionBeside the demonstration of the relationship between -374A allele and increased risk of CAE for the first time, our results indicate that antihypertensive and antidiabetic treatment in CAE patients causes an increase in sRAGE levels. The lack of an association between the expected -374A allele and low sRAGE levels in total CAE group was attributed to the high proportion of hypertensive patients and hence to antihypertensive treatment. Moreover, the RAGE -374A allele is associated with younger age at CAE and higher Plt, suggesting that -374A may also be associated with platelet activation, which plays a role in the pathogenesis of CAE. However, our data need to be confirmed in a large study for definitive conclusions.

Analysis of changes in high-mobility group box 1, receptor for advanced glycation endproducts, and T helper 17/regulatory T balance in severe preeclampsia with acute heart failure.

We measured the levels of High-Mobility Group Box 1 (HMGB1), Receptor for Advanced Glycation Endproducts (RAGE), T Helper 17 cells (Th17), Regulatory T cells (Treg), and related cytokines in the peripheral blood of patients with severe preeclampsia (SPE) complicated with acute heart failure (AHF) to explore the expression changes in these indicators. In total, 96 patients with SPE admitted to Gansu Provincial Maternity and Child-care Hospital between June 2020 and June 2022 were included in the study. The patients were divided into SPE+AHF (40 patients) and SPE (56 patients) groups based on whether they suffered from AHF. Additionally, 56 healthy pregnant women who either received prenatal examinations or were admitted to our hospital for delivery during the same period were selected as the healthy control group. An enzyme-linked immunosorbent assay was performed to detect the expression levels of HMGB1, RAGE, interleukin (IL)-17, IL-6, transforming growth factor β (TGF-β), IL-10, and NT-proBNP in plasma. Flow cytometry was employed to determine the percentages of Th17 and Treg cells. Compared to the healthy control group, the SPE+AHF and SPE groups had higher plasma levels of HMGB1 and RAGE expression, higher Th17 percentage and Th17/Treg ratio, and lower Treg percentage. Compared to the SPE group, the SPE+AHF group had higher plasma levels of HMGB1 and RAGE expression, higher Th17 percentage and Th17/Treg ratio, and lower Treg percentage (P<.05). In patients with SPE with AHF, plasma HMGB1 was positively correlated with RAGE, Th17, Th17/Treg, IL-17, and IL-6 and was negatively correlated with TGF-β and IL-10 (P<.05). Our findings revealed that patients with SPE with AHF had elevated levels of HMGB1 and RAGE while exhibiting Th17/Treg immune imbalance, suggesting that the abnormal expression of these indicators may be involved in the pathogenesis of SPE with AHF.

Predictive value of combination of lung injury prediction score and receptor for advanced glycation end‑products for the occurrence of acute respiratory distress syndrome.

The present study evaluated the predictive value of the combination of the lung injury prediction score (LIPS) and receptor for advanced glycation end-products (RAGE) for the occurrence of acute respiratory distress syndrome (ARDS) in critically ill patients with ARDS risk factors. A total of 551 patients with risk factors of ARDS were divided into an ARDS group and a non-ARDS group. LIPS was computed within 6 h of admission into the ICU, and the plasma concentration of RAGE was detected within 24 h of admission. Multivariate analysis was performed to identify independent associations, and the predictive values for ARDS occurrence were assessed with receiver operating characteristic (ROC) curve. Within 7 days after admission into the ICU, ARDS occurred in 176 patients (31.9%). Multivariate analysis demonstrated that LIPS [odds ratio (OR), 1.282; 95% confidence interval (CI), 1.108-1.604], RAGE levels (OR, 2.359; 95% CI, 1.351-4.813) and Acute Physiology and Chronic Health Evaluation II score (OR, 1.167; 95% CI, 1.074-1.485) were independently associated with ARDS occurrence. ROC curves demonstrated that the area under curve (AUC) of LIPS, RAGE levels and their combination was 0.714 [standard error (SE), 0.023; 95% CI, 0.670-0.759], 0.709 (SE, 0.025; 95% CI, 0.660-0.758) and 0.889 (SE, 0.014; 95% CI, 0.861-0.917), respectively. The AUC of LIPS combined with RAGE levels was significantly higher compared with those of LIPS (0.889 vs. 0.714; Z=6.499; P<0.001) and RAGE (0.889 vs. 0.709; Z=6.282; P<0.001) levels alone. In conclusion, both LIPS and RAGE levels were independently associated with ARDS occurrence in critically ill patients with ARDS risk factors, and had medium predictive values for ARDS occurrence. Combination of LIPS with RAGE levels increased the predictive value for ARDS occurrence.

Abstract 14597: Beyond Sex Bias: The Uncharted Role of Rage Signaling in Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension (PAH) is a life-threatening disease that initiates in response to pulmonary artery endothelial cells (PAEC) damage followed by inadequate repair. The Receptor for Advanced Glycation Endproducts (RAGE) triggered upon the damage, plays a crucial role in vascular regeneration. However, its specific impact on PAH remains incompletely explored. Hypothesis: In this study, we investigated the sex-specific outcome of RAGE deletion on PAEC homeostasis. Methods: The effect of the global RAGE knockout (KO) on pulmonary hemodynamics, cardiac and endothelial function was studied disaggregated by sex in WT and RAGE KO rats. Endothelial integrity was evaluated via the expression of endothelial junction proteins, the activity of barrier disruptive signaling pathways, and in vivo pulmonary vascular permeability assay. To understand the significance of diminished RAGE signaling in male PAH, we measured membrane RAGE levels in untreated and Sugen/Hypoxia treated rats of both sexes and examined the publicly available single-cell transcriptomic profiles of human PAECs. Results: Male but not female RAGE KO rats developed a spontaneous PAH characterized by a significant increase in the right ventricle (RV) systolic pressure and RV hypertrophy. The PAH phenotype in males corresponded with a male-specific decrease in the expression of CD31 (WT vs. RAGE KO: 1.0 ± 0.07 vs. 0.1 ± 0.02, p &lt;0001, N=6), activation of p38/RhoA signaling axis (p-p38 in WT vs. RAGE KO: 1.0 ± 0.2 vs. 3.2 ± 0.6, p=0.01, N=4), significant PAEC cytoskeletal rearrangement, and increased FITC-dextran extravasation, while female RAGE KOs remained unaffected. We also discovered that Sugen/Hypoxia treatment induced a substantial loss of membrane RAGE, specifically in males. Additionally, human PAEC transcriptomic data revealed that RAGE is expressed primarily in young females but not in males or older females. Conclusions: We conclude that the male sex associates with a reduced RAGE expression and signaling in PAEC, which is further diminished in PAH. The disruption in RAGE signaling, in turn, impairs the pulmonary endothelial barrier, instigates spontaneous PAH, and may contribute to the more severe phenotype observed in male PAH patients.

RAGE as a Novel Biomarker for Prostate Cancer: A Systematic Review and Meta-Analysis.

The receptor for advanced glycation end-products (RAGE) has been implicated in driving prostate cancer (PCa) growth, aggression, and metastasis through the fueling of chronic inflammation in the tumor microenvironment. This systematic review and meta-analysis summarizes and analyzes the current clinical and preclinical data to provide insight into the relationships among RAGE levels and PCa, cancer grade, and molecular effects. A multi-database search was used to identify original clinical and preclinical research articles examining RAGE expression in PCa. After screening and review, nine clinical and six preclinical articles were included. The associations of RAGE differentiating benign prostate hyperplasia (BPH) or normal prostate from PCa and between tumor grades were estimated using odds ratios (ORs) and associated 95% confidence intervals (CI). Pooled estimates were calculated using random-effect models due to study heterogeneity. The clinical meta-analysis found that RAGE expression was highly likely to be increased in PCa when compared to BPH or normal prostate (OR: 11.3; 95% CI: 4.4-29.1) and that RAGE was overexpressed in high-grade PCa when compared to low-grade PCa (OR: 2.5; 95% CI: 1.8-3.4). In addition, meta-analysis estimates of preclinical studies performed by albatross plot generation found robustly positive associations among RAGE expression/activation and PCa growth and metastatic potential. This review demonstrates that RAGE expression is strongly tied to PCa progression and can serve as an effective diagnostic target to differentiate between healthy prostate, low-grade PCa, and high-grade PCa, with potential theragnostic applications.

Diagnostic Utility and Tendency of Bronchial and Serum Soluble Receptor for Advanced Glycation EndProducts (sRAGE) in Lung Cancer.

The receptor for advanced glycation end-products (RAGE) may serve as a diagnostic and prognostic biomarker of lung cancer and lung injury. We explored whether the serum and bronchial levels of soluble RAGE (sRAGE) distinguished infectious lung diseases from lung cancer. We collected serum and bronchial washing fluids (BWFs) from patients diagnosed with pneumonia, tuberculosis, or preoperative lung cancer from April 2016 to March 2022. sRAGE levels were measured using an enzyme-linked immunosorbent assay and we drew receiver operating characteristic (1) curves to determine the cut-off values affording the best diagnostic sensitivities. We enrolled 81 patients including 20 with tuberculosis, 30 with pneumonia, and 31 with lung cancer. Of the 81, 61% were males and the median age was 66 years. The median serum level of sRAGE was 822 (678-1168 pg/mL) and did not differ significantly between the three groups. The median bronchial sRAGE level was 167 (83-529 pg/mL) but 231 (108-649 pg/mL) for tuberculosis, 366 (106-706 pg/mL) for pneumonia, and 103 (32-254 pg/mL) for lung cancer patients (p = 0.018). The ROC curve for the bronchial sRAGE values of lung cancer patients revealed that the optimal cut-off was 118.9 pg/mL. This afforded a sensitivity of 76%, a specificity of 58%, and an area under the ROC curve of 0.695 (p = 0.005). The level of bronchial sRAGE differed significantly between patients with lung cancer and other respiratory diseases; that level may serve as an auxiliary diagnostic biomarker.

Polymorphisms -374 T/A and -429 T/C of the Receptor for Advanced Glycation End-Products (RAGE) and Serum Levels of RAGE (sRAGE) Are Not Associated with Metabolic Syndrome.

RAGE is a multi-ligand transmembrane glycoprotein that promotes biological signals associated with inflammatory responses and degenerative diseases. sRAGE is a soluble variant, proposed as an inhibitor of RAGE activity. -374 T/A and -429 T/C polymorphisms of the advanced glycation end products receptor AGER gene are associated with the development of some diseases, such as type of cancer, cardiovascular disease, and micro and macrovascular disease in diabetes among others but their role in metabolic syndrome (MS) is still unknown. We studied 80 healthy men without MS, and 80 men with MS according to the harmonized criteria. -374 T/A and -429 T/C polymorphisms were genotyped by RT-PCR, and sRAGE was measured by ELISA. Allelic and genotypic frequencies did not differ between Non-MS and MS groups (-374 T/A p = 0.48, p = 0.57 and -429 T/C p = 0.36, p = 0.59). Significant differences were found in fasting glucose levels and diastolic blood pressure among the genotypes of the -374 T/A polymorphism in the Non-MS group (p < 0.01 and p = 0.008). Glucose levels were different between -429 T/C genotypes in the MS group (p = 0.02). sRAGE levels were similar in both groups, but in the Non-MS group showed a significant difference between individuals with only 1 or 2 components of the metabolic syndrome (p = 0.047). However, no associations of any SNP with MS were found (recessive model p = 0.48, dominant model p = 0.82 for -374 T/A; recessive model p = 0.48, dominant model p = 0.42 for -429 T/C). -374 T/A and -429 T/C polymorphisms are not associated with MS in Mexican population and have no influence on serum sRAGE levels.

RAGE signaling regulates the progression of diabetic complications.

Diabetes, the ninth leading cause of death globally, is expected to affect 642 million people by 2040. With the advancement of an aging society, the number of patients with diabetes having multiple underlying diseases, such as hypertension, obesity, and chronic inflammation, is increasing. Thus, the concept of diabetic kidney disease (DKD) has been accepted worldwide, and comprehensive treatment of patients with diabetes is required. Receptor for advanced glycation endproducts (RAGE), a multiligand receptor, belonging to the immunoglobulin superfamily is extensively expressed throughout the body. Various types of ligands, including advanced glycation endproducts (AGEs), high mobility group box 1, S100/calgranulins, and nucleic acids, bind to RAGE, and then induces signal transduction to amplify the inflammatory response and promote migration, invasion, and proliferation of cells. Furthermore, the expression level of RAGE is upregulated in patients with diabetes, hypertension, obesity, and chronic inflammation, suggesting that activation of RAGE is a common denominator in the context of DKD. Considering that ligand-and RAGE-targeting compounds have been developed, RAGE and its ligands can be potent therapeutic targets for inhibiting the progression of DKD and its complications. Here, we aimed to review recent literature on various signaling pathways mediated by RAGE in the pathogenesis of diabetic complications. Our findings highlight the possibility of using RAGE-or ligand-targeted therapy for treating DKD and its complications.

Soluble receptor for advanced glycation end-products (sRAGE) in childhood obesity: association with gene expression of RAGE and cardiometabolic markers.

Introduction: advanced glycation end-products (AGEs) interact with the receptor for AGEs (RAGE). Full-length RAGE is associated with intracellular signal transduction, and soluble-RAGE (sRAGE) lacks the transmembrane and cytoplasmic domains, acting as a competitive inhibitor of AGEs-RAGE binding. sRAGE levels in healthy children are associated with cell surface expression of RAGE. However, the expression of RAGE has not been explored in childhood obesity. Objective: the study aim was to evaluate the sRAGE levels and the gene expression of RAGE in children and its association with cardiometabolic markers. Methods: this is a cross-sectional study with 6-11-year children, 20 with overweight and 20 with obesity. Anthropometric measurements included waist circumference (cm) (WC), neck circumference (NC), weight (kg), fat mass (%), trunk fat (kg), muscular mass (kg), height (cm), and body mass index (BMI) (kg/m2). Blood samples following an overnight fast were collected to measure glucose (mg/dl) and lipid profile with colorimetric methods. sRAGE was determined in serum using the enzyme-linked immunosorbent assay (ELISA). Quantitative reverse transcription (RT-qPCR) was performed to analyze RAGE transcripts in peripheral blood mononuclear cells isolated by Ficoll®-Hypaque. Results: we found higher RAGE (p = 0.0315) and lower sRAGE (p = 0.0305) levels in the obesity group. sRAGE level showed a negative correlation with RAGE (r = -0.35) and BMI (r = -0.24), and positive with HDL-cholesterol (r = 0.29). Regression analysis suggests that HDL-C and RAGE levels are predictors of sRAGE levels. Conclusions: expression of RAGE is associated with lower sRAGE levels in childhood obesity. Moreover, obese children show higher cardiometabolic risk markers, and a positively associated with sRAGE.

Effects of Butylphthalide on the expressions of HMGB1 and RAGE in frontal lobe of rats after chronic sleep deprivation

To investigate the effects of Butylphthalide on the expressions of HMGB1 and RAGE in frontal lobe of rats after chronic sleep deprivation. Chronic sleep deprivation and butylphthalide treatment was performed in Sprague Dawley(SD)rats and the rats were divided into three groups (n＝6): platform control group, chronic sleep deprivation group and chronic sleep deprivation + butylphthalide intervention group. Rats suffering chronic sleep deprivation were put in multiple platforms box for 18 h per day and sleep deprivation lasted for 28 days. Rats in butylphthalide intervention group were intraperitoneally injected with butylphthalide 100 mg/(kg·d) for 14 days after sleep deprivation. After collecting brains, high-mobility group box (HMGB1) and nuclear transcription factor kappB (NF-κB)p65 were detected by immunohistochemistry. The expression of HMGB1, silent information regulator of transcription 1 (SIRT1), receptor for advanced glycation end-products (RAGE) and NF-κB in frontal lobe were determinated by Western blot. Compared with platform control group, the expression levels of HMGB1, RAGE and nuclear NF-κB p65 were increased significantly, while the expression of SIRT1 was decreased siginificantly in frontal lobe of chronic sleep deprivation group (all P＜0.05). Compared with chronic sleep deprivation group, the expression levels of of HMGB1, RAGE and nuclear NF-κB p65 were decreased significantly, while the expression of SIRT1 was increased significantly in chronic sleep deprivation + butylphthalide intervention group (all P＜0.05). Butylphthalide can inhibit HMGB1/RAGE/NF-κB pathway in frontal lobe of rats after chronic sleep deprivation by changing the expression of HMGB1 and RAGE, and reducing the nuclear translocation of NF-κBp65.

The Burden of Impaired Serum Albumin Antioxidant Properties and Glyco-Oxidation in Coronary Heart Disease Patients with and without Type 2 Diabetes Mellitus.

Human serum albumin (HSA) has an important antioxidant activity due to the presence of the reduced cysteine at position 34, which represents the most abundant free thiol in the plasma. In oxidative-based diseases, HSA undergoes S-thiolation (THIO-HSA) with changes in the antioxidant function of albumin that could contribute to the progression of the disease. The aim of this study was to verify, for the first time, the different burdens of THIO-HSA, glycated HSA (GLY-HSA), and advanced glycation end products (AGE) accumulation both in type 2 diabetes mellitus (T2DM) patients and in non-diabetic patients, with or without coronary heart disease (CHD). In this study, we assessed the presence of modified forms of HSA, THIO-HSA, and GLY-HSA by means of mass spectrometry in 33 patients with both T2DM and CHD, in 31 patients with T2DM and without CHD, in 30 patients without diabetes with a history of CHD, and 27 subjects without diabetes and CHD. All the patients’ anthropometric and clinical data were recorded including age, sex, duration of diabetes, body mass index (BMI), blood pressure, and history of CHD defined with anamnestic data. Metabolic parameters, such as fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), lipids, pentosidine, AGE, receptor for advanced glycation end-products (RAGE) and its soluble form (sRAGE), were measured. AGE and pentosidine are significantly higher in T2DM patients with and without CHD with respect to non-diabetic patients with CHD and control subjects. RAGE levels are significantly higher in T2DM patients with respect to non-diabetic patients, and among T2DM patients, the group with CHD showed significantly higher RAGE levels than those without CHD (217 ± 171 pg/mL and 140 ± 61 pg/mL, respectively). Albumin isoforms discriminate between non-diabetic patients with CHD and T2DM patients with and without CHD and control subjects, with GLY-HSA levels higher in T2DM with and without CHD, and THIO-HSA higher in CHD patients without T2DM. Finally, we demonstrated that the oxidized forms of HSA can increase the expression of the inflammatory cytokine Tumor Necrosis Factor-alpha (TNFα) in monocytic cells. In patients with CHD, GLY-HSA and THIO-HSA have a different prevalent distribution, the first one prevailing in patients with T2DM and the second one in patients without T2DM. These findings suggest that albumin quality and homeostasis balance between glyco-oxidation and thiolation might have an impact on the antioxidant defense system in cardiovascular diseases.

An imbalance between RAGE/MR/HMGB1 and ATP1α3 is associated with inflammatory changes in rat brain harboring cerebral aneurysms prone to rupture

Background and purposeAn aneurysmal subarachnoid hemorrhage is a devastating event. To establish an effective therapeutic strategy, its pathogenesis must be clarified, particularly the pathophysiology of brain harboring intracranial aneurysms (IAs). To elucidate the pathology in brain harboring IAs, we examined the significance of the receptor for advanced glycation end-products (RAGE)/mineralocorticoid receptor (MR) pathway and Na+/K+-ATPase (ATP1α3).MethodsTen-week-old female rats were subjected to oophorectomy as well as hypertension and hemodynamic changes to induce IAs, and were fed a high-salt diet. Brain damage in these rats was assessed by inflammatory changes in comparison to sham-operated rats fed a standard diet.ResultsSix weeks after IA induction (n = 30), irregular morphological changes, i.e., an enlarged vessel diameter and vascular wall, were observed in all of the left posterior cerebral arteries (Lt PCAs) prone to rupture. Approximately 20% of rats had ruptured IAs within 6 weeks. In brain harboring unruptured IAs at the PCA, the mRNA levels of RAGE and MR were higher, and that of ATP1α3 was lower than those in the sham-operated rats (p < 0.05, each). Immunohistochemically, elevated expression of RAGE and MR, and decreased expression of ATP1α3 were observed in the brain parenchyma adjacent to the Lt PCA, resulting in increased Iba-1 and S100B expression that reflected the inflammatory changes. There was no difference between the unruptured and ruptured aneurysm rat groups. Treatment with the MR antagonist esaxerenone abrogated these changes, and led to cerebral and vascular normalization and prolonged subarachnoid hemorrhage-free survival (p < 0.05).ConclusionsRegulation of the imbalance between the RAGE/MR pathway and ATP1α3 may help attenuate the damage in brain harboring IAs, and further studies are warranted to clarify the significance of the down-regulation of the MR/RAGE pathway and the up-regulation of ATP1α3 for attenuating the pathological changes in brain harboring IAs.

Circulating levels of AGEs and soluble RAGE isoforms are associated with all-cause mortality and development of cardiovascular complications in type 2 diabetes: a retrospective cohort study

BackgroundAdvanced glycation end-products (AGEs) and their interaction with the receptor for advanced glycation end-products (RAGE) play a pivotal role in the development and progression of type 2 diabetes. In this retrospective cohort study, we explored the association of circulating levels of soluble RAGE (sRAGE) isoforms, i.e., endogenous secretory esRAGE and cleaved cRAGE, AGEs and their respective ratios with 15-year all-cause mortality in type 2 diabetes.MethodsBaseline AGEs and sRAGE isoforms concentration were measured by ELISA in 362 patients with type 2 diabetes and in 125 age- and gender-matched healthy control subjects (CTR). Independent predictors of mortality were determined using Cox proportional-hazards models and used to build and validate a nomogram for all-cause mortality prediction in type 2 diabetes.ResultsAGEs, total sRAGE, cRAGE and the AGEs/sRAGE and AGEs/esRAGE ratios were significantly increased in patients with type 2 diabetes compared to CTR (p < 0.001). In CTR subjects, but not in type 2 diabetes patients, a significant negative correlation between cRAGE and age was confirmed (p = 0.003), whereas the AGEs/sRAGE (p = 0.032) and AGEs/cRAGE (p = 0.006) ratios were positively associated with age. At an average follow-up of 15 years (4,982 person-years), 130 deaths were observed. The increase in the AGEs/cRAGE ratio was accompanied by a higher risk of all-cause mortality in patients with type 2 diabetes (HR per each SD increment = 1.30, 95% CI 1.15–1.47; p < 0.001). Moreover, sRAGE was associated with the development of major adverse cardiovascular events (MACE) in type 2 diabetes patients without previous MACE (OR for each SD increase: 1.48, 95% CI 1.11–1.89). A nomogram based on age, sex, HbA1c, systolic blood pressure, and the AGEs/cRAGE ratio was built to predict 5-, 10- and 15-year survival in type 2 diabetes. Patients were categorized into quartiles of the monogram scores and Kaplan-Meier survival curves confirmed the prognostic accuracy of the model (log-rank p = 6.5 × 10− 13).ConclusionsThe ratio between AGEs and the cRAGE isoform is predictive of 15-year survival in patients with type 2 diabetes. Our data support the assessment of circulating AGEs and soluble RAGE isoforms in patients with type 2 diabetes as predictors of MACE and all-cause mortality.

Increased Production of Interleukin-10 and Tumor Necrosis Factor-Alpha in Stimulated Peripheral Blood Mononuclear Cells after Inhibition of S100A12.

Sepsis may induce immunosuppression and result in death. S100A12 can bind to the receptor for advanced glycation end-products (RAGE) and Toll-like receptor (TLR)4 following induction of various inflammatory responses. It is unclear whether S100A12 significantly influences the immune system, which may be associated with sepsis-related mortality. We measured plasma S100A12 levels and cytokine responses (mean ± standard error mean) of lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) after S100A12 inhibition in healthy controls and patients with sepsis on days one and seven. Day one plasma soluble RAGE (sRAGE) and S100A12 levels in patients with sepsis were significantly higher than those in controls (2481.3 ± 295.0 vs. 1273.0 ± 108.2 pg/mL, p < 0.001; 530.3 ± 18.2 vs. 310.1 ± 28.1 pg/mL, p < 0.001, respectively). Day seven plasma S100A12 levels in non-survivors were significantly higher than those in survivors (593.1 ± 12.7 vs. 499.3 ± 23.8 pg/mL, p = 0.002, respectively). In survivors, plasma sRAGE levels were significantly decreased after 6 days (2297.3 ± 320.3 vs. 1530.1 ± 219.1 pg/mL, p = 0.009, respectively), but not in non-survivors. Inhibiting S100A12 increased the production of tumor necrosis factor (TNF)-α and interleukin (IL)-10 in stimulated PBMCs for both controls and patients. Therefore, S100A12 plays an important role in sepsis pathogenesis. S100A12 may competitively bind to TLR4 and RAGE, resulting in decreased IL-10 and TNF-α production.

Lycopene can modulate the LRP1 and RAGE transporters expression at the choroid plexus in Alzheimer’s disease rat

• Lycopene may improve amyloid-β clearance through CP epithelial cells. • Lycopene can modulate the LRP1 and RAGE transporters expression at the CP. • Lycopene can enhance antioxidant enzymatic system in the CP of AD rats. • Lycopene can suppress RAGE/NF-κB signaling pathway in the CP of AD rats. This work sought to investigate whether lycopene administration modulated the expression of two major Aβ transporters, i.e., the low-density lipoprotein receptor protein-1 (LRP1) and the receptor for advanced glycation end-products (RAGE) being localized to the choroid plexus (CP) in the Alzheimer’s disease (AD) rats. Forty-eight adult male Wistar rats were assigned into four equal groups. Results showed that lycopene administration attenuated Aβ accumulation, increased the LRP1 levels, as well as decreased the RAGE levels in the cerebrospinal fluid (CSF) or the CP. Furthermore, lycopene administration significantly enhanced antioxidant enzymatic system for inactivating and controlling ROS, suppressed RAGE/nuclear factor-κB (NF-κB) signaling pathway and the production of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in the CP of AD rats. Our data presented in this report provided the firsthand evidence that lycopene administration might provide a novel therapeutic approach to improve Aβ clearance and prevent CP epithelial cells neuroinflammation in AD.

Increased Levels of Soluble RAGE in CLL Patient Plasma Has a Protective Effect on CLL Disease Progression

Background: Receptor for advanced glycation end-products (RAGE) is the primary receptor for the inflammatory molecule HMGB1. We previously demonstrated that HMGB1 differentiates nurse like cells (NLC), and that increased levels HMGB1 in the plasma of CLL patients and overexpression of RAGE in CLL lymph nodes is associated with a poorer clinical outcome. Moreover, we have shown that HMGB1 induced activation of NF-κB in primary CLL cells in vitro . Soluble RAGE (sRAGE) is a reported antagonistic decoy receptor of plasma HMGB1, and limits chronic inflammation. The pool of plasma sRAGE originates from 2 main sources - alternative splicing to produce endogenous secreted RAGE (esRAGE), or from surface RAGE ectodomain shedding catalyzed by ADAM10. In a healthy setting, HMGB1 and sRAGE plasma levels are inversely correlated, with increased levels of sRAGE limiting inflammatory responses. RAGE shedding in response to saturating levels of ligand (i.e. HMGB1) establishes a negative feedback loop, dampening inflammatory signaling by sequestering RAGE ligands. In chronic disease, the HMGB1-sRAGE inverse relationship is frequently reversed. The functional impact of sRAGE is poorly documented in cancer, and its role in CLL is currently unknown.We hypothesize that sRAGE could have a protective effect in CLL and could dampen HMGB1-mediated disease progression. The aim of this study is to characterise the clinical significance of sRAGE in CLL and investigate whether RAGE undergoes membrane shedding to confer a protective effect in CLL.Methods: sRAGE plasma levels were measured by ELISA in 54 CLL patients and 15 healthy controls. sRAGE protein mass was assessed by Western blotting and compared to matched patient ADAM10 whole cell expression. ADAM10 inhibitor studies and HMGB1-induced RAGE shedding was performed in RAGE-transfected HEK293 cell line and primary CLL cells; sRAGE production was analyzed by ELISA and surface RAGE expression determined by flow cytometry. sRAGE containing media was produced by HEK293 cell line transfected with esRAGE isoform gene sequence; sRAGE containing media (2ng/ml) was used to assess the effect on primary CLL NLC differentiation.Results: sRAGE plasma levels were significantly higher in CLL patients compared to healthy controls (median 60.0pg/ml ± 79.5 interquartile range and 31.0pg/ml ±46.9, respectively; P <0.01), but fell below levels capable of full HMGB1 inhibition for the same patient cohort (72.2ng/ml ±111.4). Absence of a negative correlation between HMGB1 and sRAGE suggested a breakdown in the negative feedback loop in CLL, compared to the classical inverse trend observed for the healthy controls. Patients with high levels of plasma sRAGE had an increased time to first treatment (P=0.0134; n=26) and sRAGE levels were increased in patients who had reached remission following treatment compared to pre-treatment samples, suggesting that sRAGE provides a protective effect on CLL disease progression.CLL plasma sRAGE is of shorter length than cellular full-length RAGE and esRAGE from primary CLL cells, suggesting sRAGE originates from ectodomain shedding. ADAM10 expression, the main RAGE sheddase, is independent of sRAGE plasma levels assessed by Western blotting. ADAM10 stimulation with ionomycin induced RAGE ectodomain shedding into cell culture medium in RAGE-transfected HEK293 cell line (2270.0ng/ml) compared to untreated cells, without altering surface RAGE or ADAM10 expression. Ionomycin-induced RAGE shedding was abrogated by pre-treatment with ADAM10 inhibitor, GI254023X (45.5ng/ml). Ionomycin induced apoptosis in primary CLL cells, so could not be investigated for RAGE shedding, but our data demonstrates that saturating HMGB1 levels induces RAGE shedding in CLL. Finally, sRAGE-containing media did not reduce primary CLL NLC differentiation in vitro after 1-2 weeks culture.Conclusions: Our data demonstrates for the first time that plasma sRAGE limits CLL disease progression by prolonging time to first treatment and sustaining stable disease following treatment. sRAGE originates from ectodomain shedding, is dependent on ADAM10 and inducible by HMGB1. Although sRAGE failed to block NLC differentiation in vitro, it contributes to the extracellular mileu ‘cocktail’ shaping the CLL microenvironment. We therefore propose that HMGB1 and sRAGE levels could be useful plasma markers for inflammatory microenvironment and therapy monitoring. DisclosuresGribben:Acerta: Honoraria; Pharmacyclics: Honoraria; Celgene: Honoraria; TG Therapeutics: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria; Kite: Honoraria; Abbvie: Honoraria; Genentech/Roche: Honoraria.

Overexpression of the receptor for advanced glycation end-products in the auditory cortex of rats with noise-induced hearing loss

BackgroundThe receptor for advanced glycation end-products (RAGE) is involved in neuroinflammation. This study investigated the changes in RAGE expression following noise-induced hearing loss.MethodsThree-week-old female Sprague–Dawley rats were exposed to 115 dB SPL white noise for 4 h daily for 3 d (noise group, n = 16). In parallel, age and sex-matched control rats were raised under standard conditions without noise exposure (control group, n = 16). After 2 h (noise immediate, n = 8) and 4 wk (noise 4-week, n = 8) of noise exposure, the auditory cortex was harvested and cytoplasmic and nuclear fractions were isolated. The gene expression levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL6), interleukin 1 beta (IL1β), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and RAGE were evaluated using real-time reverse transcription polymerase chain reaction. The protein expression levels of nuclear RAGE and cytosolic RAGE were evaluated using western blotting. Additionally, matrix metalloproteinase 9 (MMP9) was pharmacologically inhibited in the noise immediate group, and then nuclear and cytosolic RAGE expression levels were evaluated.ResultsThe noise immediate and noise 4-week groups exhibited increased auditory thresholds at 4, 8, 16, and 32 kHz frequencies. The genes encoding the pro-inflammatory cytokines TNF-α, IL6, IL1β, and NF- κB were increased 3.74, 1.63, 6.42, and 6.23-fold in the noise immediate group, respectively (P = 0.047, 0.043, 0.044, and 0.041). RAGE mRNA expression was elevated 1.42-fold in the noise 4-week group (P = 0.032). Cytosolic RAGE expression was increased 1.76 and 6.99-fold in the noise immediate and noise 4-week groups, respectively (P = 0.04 and 0.03). Nuclear RAGE expression was comparable between the noise and control groups. matrix metalloproteinase 9 (MMP9) inhibition reduced cytosolic RAGE expression in the noise immediate group (P = 0.004).ConclusionsNoise exposure increased the expression of cytosolic RAGE in the auditory cortex and upregulated pro-inflammatory genes, but this response could be alleviated by MMP9 inhibition.

Pseudomonas aeruginosa significantly increases expression of receptor for advanced glycation endproducts (RAGE) in the septicemia suffering patients

Receptor for Advanced Glycation Endproducts (RAGE) is a cell surface receptor, which recognizes several endogenous and exogenous molecules and subsequently induces expression of several molecules including chemokines. Chemokines are members of the cytokine superfamily and participate in several immune system functions, including cell migration, inflammation, angiogenesis/angiostasis etc. CXC ligand 11 (CXCL11) is an important chemokine which participates in the induction of appropriate immune responses against microbes, including bacteria. The main mechanisms responsible to overcome septicemia are yet to be clarified. Thus, it has been hypothesized that RAGE may participate in induction of CXCL11 in response to the microbial agents. Due to the fact that immune responses play key roles in limitation of infection, it has been proposed that RAGE may inhibit spread of septicemia. Therefore, in this project mRNA levels of RAGE and CXCL11 were explored in the patients suffering from septicemia versus healthy controls. RAGE and CXCL11 expression levels in the 80 subjects, including 40 septicemia patients and 40 healthy controls were explored using Real-Time PCR technique. Accordingly, by using the specific primer against RAGE and CXCL11 in a Rotorgene vehicle the mRNA levels have been determined. The septicemia and the sources of the bacteria in the blood were diagnosed using microbial cultures. The results demonstrated that although mRNA levels for RAGE and CXCL11 did not change in the septicemia patients vs. healthy controls, mRNA levels of RAGE were significantly higher in the patients infected by Pseudomonas aeruginosa compared to those infected by other bacteria, Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii. RAGE and CXCL11 mRNA levels did not differ among male and female patients. Based on the results it seems that RAGE is a critical receptor against P. aeruginosa during septicemia and more investigations, especially on the RAGE down-stream molecules can clarify its main roles against P. aeruginosa.