Receptor For Advanced Glycation End Products Research Articles

The RAGE/multiligand axis: a new actor in tumor biology

The receptor for advanced glycation end-products (RAGE) is a multiligand binding and single-pass transmembrane protein which actively participates in several chronic inflammation-related diseases. RAGE, in addition to AGEs, has a wide repertoire of ligands, including several damage-associated molecular pattern molecules or alarmins such as HMGB1 and members of the S100 family proteins.Over the last years, a large and compelling body of evidence has revealed the active participation of the RAGE axis in tumor biology based on its active involvement in several crucial mechanisms involved in tumor growth, immune evasion, dissemination, as well as by sculpturing of the tumor microenvironment as a tumor-supportive niche. In the present review, we will detail the consequences of the RAGE axis activation to fuel essential mechanisms to guarantee tumor growth and spreading.

Exercise, Advanced Glycation End Products, and Their Effects on Cardiovascular Disorders

Abstract Lifelong accumulation of advanced glycation end products (AGEs) is linked to cardiovascular disease (CVD). As a result of AGEs, cardiovascular dysfunction develops and progresses via two main mechanisms: cross-linking AGEs with tissue proteins and binding of AGEs to their receptor for AGE (RAGE). In addition, the formation of atherosclerotic plaques in these patients may be due to increased oxidative stress, leading to an elevation in blood circulation and tissue AGEs. Increasing physical activity is a critical approach among the different strategies to manage the deleterious effects of these changes caused by disease. Exercise prevents the accumulation of AGEs and slows the progression of chronic disease sequels. Exercise reduces AGE levels through a reduction of insulin sensitivity, fat mass, inflammation, and RAGE expression. An improvement in glucose metabolism and glycemic control are also other possible explanations. Reduced peripheral insulin resistance may attenuate AGE accumulation. Physical exercise causes more antioxidant enzyme secretion and reduces oxidative stress. Antioxidant and anti-inflammatory endothelial function is improved by exercise. After exercise, subendothelial matrix stiffness decreases, and endothelial function is improved. In this current study, the association between AGEs and exercise and their interaction effects on CVD are discussed.

Estimation of Soluble Receptor Advanced Glycation End-Products in Diabetic Patients Type 2 Patients in Najaf City, Iraq

Diabetes is a complex metabolic disruption affecting the glucose level of the human body. Intracellular hyperglycemia promotes mitochondrial reactive oxygen species (ROS) production, ROS directly improve the expression of inflammatory, these inflammations are associated with the level of soluble receptors for advanced glycation end-products (sRAGE) in serum. in this work assessed the level of (sRAGE) and study its potential as a biomarker for diabetes mellitus. The research included 108 Iraqis between the ages of (35-65) years of both sexes. The individuals were divided into two groups, (63) with type 2 diabetes mellitus (T2DM) and (45) control group, most of the tests serum have been measurements by colourimetric methods, and sRAGE levels in serum were evaluated by ELISA Technique. The results of the investigation showed that the sRAGE mean was more elevated compared to the mean of the control group (p < 0.00001). Statistical study of Pearson's correlation illustrated that the sRAGE level is high positively with FBG, and HBA1C (r = 0.878, p < 0.00001), (r = 0.422, P=0.05) respectively. While, negatively correlation with insulin level (r = -0.204, p = 0.010). Furthermore, most the sRAGE level denoted a positive significant correlation with kidney function parameters inclusive urea, creatinine, and ACR, except eGFR was a negative significant (r = 0.422, p = 0.05), (r = 0.501, p = 0.01), (r = 0.435, p = 0.030), (r = -0.539, p = 0.011) respectively. These results support a strong relationship between serum sRAGE level and indicators of hyperglycemia, so we can conclude that it is a great biomarker for predicting of diabetes mellitus. Keywords: ELISA, HOMA, Insulin, sRAGE, Inflamations.

Serum Calprotectin - a NET Product - as a Biomarker of Disease Activity in Patients with Systemic Lupus Erythematosus: A Single-Center Case-Control Study from Poland.

BackgroundCalprotectin (S100A8/A9 or myeloid-related protein 8/14) is a heterodimeric S100 complex expressed in leukocytes. Calprotectin participates in development of the inflammatory response by binding to receptors for advanced glycation end-products (RAGE) and Toll-like receptors (TLR). The clinical activity of systemic lupus erythematosus (SLE) is evaluated using the Systemic Lupus International Collaborating Clinics (SLICC) criteria and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). This Polish single-center case-control study aimed to evaluate serum levels of calprotectin as a rapid diagnostic biomarker of SLE (59 patients with SLE were compared with 52 healthy controls).Material/MethodsCalprotectin concentration was measured with the use of enzyme-linked immunosorbent assay (ELISA). The SLE activity of the patients was assessed by the SLEDAI scale. Statistical analysis of the results was carried out using MedCalc 15.8 software. P<0.05 was considered statistically significant.ResultsA significantly higher concentration of calprotectin was found in the study group compared to the control group (medians: 3.11 vs 2.45 ng/ml; P=0.0013). We found that calprotectin has high sensitivity (89.83%) and specificity (53.85%) in differentiating between SLE patients and healthy volunteers. We found that calprotectin has very high sensitivity (100%) and specificity (82.46%) in detection of patients with moderate and severe SLE assessed using SLEDAI.ConclusionsConsistent with previous studies, serum calprotectin level was revealed to have potential as a rapid diagnostic biomarker of disease activity in patients with SLE.

In Patients with Chronic Kidney Disease Advanced Glycation End-Products Receptors Isoforms (sRAGE and esRAGE) Are Associated with Malnutrition.

Background: in patients with chronic kidney disease (CKD), the inflammatory and pro-oxidant milieu may contribute to malnutrition development. In this study, we investigated the relationship between inflammation, advanced glycation end-products (AGEs), and their receptors (RAGEs) with malnutrition in CKD patients. Methods: we evaluated 117 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, soluble RAGEs isoforms, and inflammatory interleukins by ELISA. Malnutrition was assessed by a malnutrition inflammation score. Results: mean age was 80 ± +11 years, eGFR was 25 ± +11 mL/min/1.73 m2 and BMI was 28 ± 5 Kg/m2. Malnourished individuals were older, had lower estimated protein intake (nPCR 0.65 ± 0.2 vs. 0.8 ± 0.2 vs. 0.8 ± 0.3, p = 0.01), higher C reactive protein (CRP 0.6 ± 1 vs. 0.6 ± 0.7 vs. 0.17 ± 0.13, p = 0.02) and tumor necrosis factor α (TNF α 14.7 ± 8.7 vs. 15.6 ± 8 vs. 11.8 ± 5.8, p = 0.029). Malnourished patients had higher sRAGE (2813 ± 1477 vs. 2158 ± 1236 vs. 2314 ± 1115, p = 0.035) and esRAGE (648 [408–1049] vs. 476 [355–680] vs. 545 [380–730] p = 0.033). In the multivariate analysis, only sRAGE maintained its association with malnutrition (p = 0.02) independently of aging and inflammation. Conclusions: in CKD patients, RAGEs isoforms, but not AGEs, are associated with malnutrition, irrespective of systemic inflammation, aging, and renal function.

Effects of diabetes on osteocytes.

Better understanding of the mechanisms underlying skeletal dysfunction in the context of diabetes is needed to guide the development of therapeutic interventions to reduce the burden of diabetic fractures. Osteocytes, the 'master regulators' of bone remodeling, have emerged as key culprits in the pathogenesis of diabetes-related skeletal fragility. Both type 1 diabetes and type 2 diabetes cause chronic hyperglycemia that, over time, reduces bone quality and bone formation. In addition to acting as mechanosensors, osteocytes are important regulators of osteoblast and osteoclast activities; however, diabetes leads to osteocyte dysfunction. Indeed, diabetes causes the accumulation of advanced glycation end-products and senescent cells that can affect osteocyte viability and functions via increased receptor for advanced glycation endproducts (RAGE) signaling or the production of a pro-inflammatory senescence-associated secretory phenotype. These changes may increase osteocyte-derived sclerostin production and decrease the ability of osteocytes to sense mechanical stimuli thereby contributing to poor bone quality in humans with diabetes. Osteocyte dysfunction exists at the nexus of diabetic skeletal disease. Therefore, interventions targeting the RAGE signaling pathway, senescent cells, and those that inhibit sclerostin or mechanically stimulate osteocytes may alleviate the deleterious effects of diabetes on osteocytes and bone quality.

Role of RAGE in the Pathogenesis of Neurological Disorders.

This review reflects upon our own as well as other investigators' studies on the role of receptor for advanced glycation end-products (RAGE), bringing up the latest information on RAGE in physiology and pathology of the nervous system. Over the last ten years, major progress has been made in uncovering many of RAGE-ligand interactions and signaling pathways in nervous tissue; however, the translation of these discoveries into clinical practice has not come to fruition yet. This is likely, in part to be the result of our incomplete understanding of this crucial signaling pathway. Clinical trials examining the therapeutic efficacy of blocking RAGE-external ligand interactions by genetically engineered soluble RAGE or an endogenous RAGE antagonist, has not stood up to its promise; however, other trials with different blocking agents are being considered with hope for therapeutic success in diseases of the nervous system.

Soluble RAGE in COPD, with or without coexisting obstructive sleep apnoea

BackgroundHypoxia can reduce the levels of soluble receptor for advanced glycation end-products (sRAGE), a new anti-inflammatory biomarker of COPD. We assessed sRAGE in patients with hypoxia-related diseases such as COPD, OSA and OSA-COPD overlap.MethodsPlasma levels of sRAGE were measured in 317 subjects at baseline (57 heathy nonsmokers [HNS], 84 healthy smokers [HS], 79 OSA, 62 COPD and 35 OSA-COPD overlap patients) and in 294 subjects after one year of follow-up (50 HNS, 74 HS, 77 OSA, 60 COPD and 33 overlap).ResultsAfter adjusting for age, sex, smoking status and body mass index, sRAGE levels showed a reduction in OSA (− 12.5%, p = 0.005), COPD (− 14.8%, p < 0.001) and OSA-COPD overlap (− 12.3%, p = 0.02) compared with HNS. There were no differences when comparing sRAGE plasma levels between overlap patients and those with OSA or COPD alone. At follow-up, sRAGE levels did not change significantly in healthy subjects, COPD and OSA or OSA-COPD overlap nontreated with continuous positive airway pressure (CPAP). Moreover, in patients with OSA and OSA-COPD overlap who were treated with CPAP, sRAGE increased significantly.ConclusionsThe levels of sRAGE are reduced in COPD and OSA. Treatment with CPAP appears to improve sRAGE levels in patients with OSA who also had COPD.

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.

Abstract 12: Social isolation promotes mammary cancer recurrence, increases IL6/JAK/STAT3 signaling and causes mitochondrial dysfunction in tamoxifen treated rats, and a traditional herbal mixture reverses all these changes

Abstract Social isolation is associated with increased risk and mortality from many diseases, such as breast cancer. Socially isolated breast cancer survivors have a 43% higher risk of recurrence and a 64% higher risk of breast cancer-specific mortality than socially integrated survivors. Since Covid-19 has dramatically increased the incidence of social isolation, it is important to determine if social isolation affects the response to endocrine therapy and/or recurrence after the therapy is completed. Since previous studies indicate that social isolation increases circulating inflammatory cytokines, we investigated if an anti-inflammatory herbal mixture Jaeumkanghwa-tang (JGT) prevents the adverse effects of social isolation on breast cancer mortality. Estrogen receptor positive mammary tumors were initiated with 7,12-dimethylbenz[a]anthracene. When a rat developed a palpable mammary tumor, it was either socially isolated (SI) by housing it singly or a rat was allowed to remain group-housed (GH). Tamoxifen (340ppm via diet) or tamoxifen + JGT (500ppm via drinking water) started when the first mammary tumor reached a size of 11 mm in diameter. Tamoxifen administration ended when a complete response to this therapy had lasted for 9 weeks (corresponds to 5 years in women). During tamoxifen therapy, social isolation non-significantly reduced the rate of complete responses to 21%, from 31% in GH group (p&amp;gt;0.05). After the therapy was completed, SI significantly increased local mammary tumor recurrence (p&amp;lt;0.001; 45% GH vs 75% SI). RNAseq analysis was performed in the mammary glands. Gene set enrichment analysis (GSEA) of transcriptome showed that the increased recurrence risk in socially isolated rats was associated with an enrichment of IL6/JAK/STAT3 signaling: this result was confirmed in the tumors. In addition, oxidative phosphorylation (OXPHOS) pathway was suppressed: the suppressed genes included those involved in mitochondrial pyruvate transport and conversion of pyruvate to acetyl CoA as well as genes in the TCA cycle and mediating electron transport in mitochondrial complexes I-IV. Social isolation also increased the expression of inflammatory receptor for advanced glycation end-products (RAGE) (p≤0.05). Consumption of an anti-inflammatory JGT inhibited IL6/JAK/STAT3 signaling, upregulated OXPHOS signaling and prevented the increased risk of mammary cancer recurrence in socially isolated animals. The percentage of recurrences in the SI rats dropped from 75% without JGT to 22% with JGT (p&amp;lt;0.001). Breast cancer mortality among socially isolated survivors may be most effectively prevented by focusing on the period following endocrine therapy using tools that inhibit IL6/JAK/STAT3 inflammatory cytokine signaling and correct disrupted OXPHOS and mitochondrial dysfunction. Citation Format: Fabia de Oliveira Andrade, Lu Jin, Robert Clarke, Imani Wood, MaryAnn Dutton, Chezaray Anjorin, Grace Rubin, Audrey Gao, Surojeet Sengupta, Kevin FitzGerald, Leena Hilakivi-Clarke. Social isolation promotes mammary cancer recurrence, increases IL6/JAK/STAT3 signaling and causes mitochondrial dysfunction in tamoxifen treated rats, and a traditional herbal mixture reverses all these changes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 12.

Correlation Analysis of CML, sRAGE, and esRAGE and the Measure of Atherosclerosis of Coronary Heart Disease.

Objective To investigate the correlation between CML, sRAGE, and esRAGE and the measure of atherosclerosis of coronary heart disease. Methods From June 2019 to December 2021, there were 100 patients in all suffering from coronary heart disease (CHD) selected as the observation group. On the basis of Gensini score, they were divided into mild group (Gensini score < 12 points), moderate group (12 points ≤ Gensini score ≤60 points), and severe group (Gensini score > 60). Apart from that, 50 normal people staying in our hospital for physical examination were chosen as the control group in the meantime. N in each group was detected and compared ε-Carboxymethyl lysine (CML), soluble advanced glycation end product receptor (sRAGE), and endogenous secretory advanced glycation end product receptor (esRAGE). Pearson correlation coefficient was adapted to assay the relevance between CML, sRAGE, and esRAGE, as well as the degree of atherosclerosis in CHD. Receiver operator characteristic (ROC) curve was applied to during the evaluation of the diagnosis of CML, sRAGE, and esRAGE, as well as their combined detection of severe atherosclerosis in CHD. Results In contrast with the control group, the level of serum CML together with sRAGE in the observation group was considerably elevated, while the level of esRAGE appeared in a downward trend (P < 0.05). The level of serum CML and sRAGE was directly proportional to the measure of atherosclerosis in CHD, while the level of esRAGE was inversely proportional to the measure of atherosclerosis in CHD (P < 0.05). That is to say that serum CML and sRAGE were positive in matter of the measure of atherosclerosis in CHD, while esRAGE negatively appertains to the measure of atherosclerosis in CHD (P < 0.05). Serum CML, sRAGE, and esRAGE could effectively diagnose severe atherosclerosis in CHD, and the combined detection sensitivity (89.79%), specificity (77.16%), accuracy (86.12%), positive predictive value (86.63%), negative predictive value (88.59%), and area under ROC curve (AUC) (0.924) were higher (P < 0.05). Conclusion CML and sRAGE, as well as esRAGE, are bound up with the degree of atherosclerosis in CHD, which is conducive to clinical diagnosis and treatment.

Soluble Receptor of Advanced Glycation End-Products (sRAGE) in Pediatric Asthma: A Prospective Study in 68 Children Aged 7 Years

Background: Asthma is a chronic inflammatory disease of the airways common in children. Soluble advanced glycation end-product receptor (sRAGE) is a blood biomarker of lung damage and inflammation. We sought to determine whether it could also be a biomarker in childhood asthma. Methods: We conducted a prospective, observational, analytical study at Clermont-Ferrand University Hospital. We measured plasma sRAGE levels in asthmatic and healthy children aged 7 years. Results: Of the 68 children assessed, 15 (22.05%) presented asthma. All presented normal respiratory function. The mean plasma sRAGE level was 1875 pg/mL in the children with asthma and 1794 pg/mL in the healthy children (p = 0.525). The mean plasma sRAGE level was significantly decreased with tobacco exposure during pregnancy: 1478 pg/mL versus 1870 pg/mL without (p = 0.007). Lower levels were observed in children living in apartments (1557 pg/mL) than in those living in houses (1863 pg/mL) (p = 0.031). Conclusions: No difference was observed in plasma sRAGE levels in children with asthma in our well-treated and controlled population. Environmental exposure may affect these levels. Further studies are required to better characterize the role of sRAGE.

Mechanism of Hypercholesterolemia-Induced Atherosclerosis

Hypercholesterolemia is involved in the development of atherosclerosis and is a risk factor for coronary artery disease, stroke, and peripheral vascular disease. This paper deals with the mechanism of development of hypercholesterolemic atherosclerosis. Hypercholesterolemia increases the formation of numerous atherogenic biomolecules including reactive oxygen species (ROS), proinflammatory cytokines [interleukin (IL)-1, IL-2, IL-6, IL-8, tumor necrosis factor-alpha (TNF-α)], expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, monocyte chemoattractant protein-1 (MCP-1), granulocyte macrophage-colony stimulating factor (GM-CSF) and numerous growth factors [insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-1 (PDGF-1) and transforming growth factor-beta (TGF-β)]. ROS mildly oxidizes low-density lipoprotein-cholesterol (LDL-C) to form minimally modified LDL (MM-LDL) which is further oxidized to form oxidized LDL (OX-LDL). Hypercholesterolemia also activates nuclear factor-kappa-B (NF-κB). The above atherogenic biomolecules are involved in the development of atherosclerosis which has been described in detail. Hypercholesterolemia also assists in the development of atherosclerosis through AGE (advanced glycation end-products)-RAGE (receptor for AGE) axis and C-reactive protein (CRP). Hypercholesterolemia is associated with increases in AGE, oxidative stress [AGE/sRAGE (soluble receptor for AGE)] and C-reactive protein, and decreases in the sRAGE, which are known to be implicated in the development of atherosclerosis. In conclusion, hypercholesterolemia induces atherosclerosis through increases in atherogenic biomolecules, AGE-RAGE axis and CRP.

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.

Inhibition of the advanced glycation end-product (RAGE) pathway prevents post-cardiac arrest sequels in rabbits

The post-cardiac arrest syndrome is characterized by an aseptic inflammatory response triggered by danger associated molecular patterns (DAMPs). Among DAMPs, high mobility group box-1 (HMGB1) is one of the major promoters of innate immunity after cardiac arrest. Previous work has shown that its “chelation” by glycyrrhizin resulted in a neuroprotective effect. However, the receptor by which HMGB1 could exert its deleterious effect still need to be determined in this situation. The aim of this study was to investigate whether the inhibition of the HMGB1 receptor for advanced glycation end-product (RAGE) could produce neurological benefits after cardiac arrest in rabbits. Anesthetized rabbits underwent 10 minutes of ventricular fibrillation. After cardiopulmonary resuscitation, they randomly received an administration of either saline (control group; n = 8) or FPS-ZM1 (1 mg/kg, i.v.), a specific inhibitor of the RAGE pathway (FPS group; n = 8). After animal awakening, survival and neurological dysfunction were assessed during 3 days. After cardiac arrest, the neurological dysfunction score was significantly lower in FPS vs. control group (37 ± 9% vs. 78 ± 6 at day 1 and 24 ± 10% vs. 92 ± 8 at day 3 in control and FPS groups, respectively; both P < 0.05). Histopathological analyses also showed reduced neuronal damages in FPS vs. control groups (96 ± 11 vs. 39 ± 14 degenerating neurons/field in the brain, respectively). An increase in interleukin (IL)-6 blood levels was observed in both groups with no significant difference among groups after cardiac arrest (203 ± 29 vs. 142 ± 44 pg/mL at t = 180 min post-resuscitation in control and FPS groups, respectively). Our findings support that the inhibition of the RAGE pathway by FPS-ZM1 results in neuroprotective effects without significant effect on IL-6 blood levels. It could explain a part of the deleterious effect of HMGB1 after cardiac arrest.

HMGB1 signaling pathway in diabetes-related dementia: Blood-brain barrier breakdown, brain insulin resistance, and Aβ accumulation.

Diabetes contributes to the onset of various diseases, including cancer and cardiovascular and neurodegenerative diseases. Recent studies have highlighted the similarities and relationship between diabetes and dementia as an important issue for treating diabetes-related cognitive deficits. Diabetes-related dementia exhibits several features, including blood-brain barrier disruption, brain insulin resistance, and Aβ over-accumulation. High-mobility group box1 (HMGB1) is a protein known to regulate gene transcription and cellular mechanisms by binding to DNA or chromatin via receptor for advanced glycation end-products (RAGE) and toll-like receptor 4 (TLR4). Recent studies have demonstrated that the interplay between HMGB1, RAGE, and TLR4 can impact both neuropathology and diabetic alterations. Herein, we review the recent research regarding the roles of HMGB1-RAGE-TLR4 axis in diabetes-related dementia from several perspectives and emphasize the importance of the influence of HMGB1 in diabetes-related dementia.

80-OR: Proinflammatory Macrophage Impairs Retrograde Axonal Transport via Inflammation and Insulin Resistance in Sensory Neurons

Inflammation, insulin resistance (IR) , and deficit of retrograde axonal transport (RAT) are implicated in the pathogenesis of diabetic polyneuropathy (DPN) . Pro-inflammatory macrophage (M1) skewed by diabetic insults causes IR in adipose tissue. The activation of Advanced Glycation End products (AGEs) - Receptor for AGEs (RAGE) signaling is involved in the macrophage polarization into M1, while its contribution to the deficit of RAT in DPN is still unclear. In this study, we investigated the implication of M1-related inflammation to RAT deficit in sensory neurons. We evaluated the activation of macrophage cell line RAW 264.7 (RAW) and neurons isolated from dorsal root ganglia (DRG) of C57BL/6 mice stimulated by 200 μg/ml of AGE. A DRG neurons-RAW co-culture system was established by seeding RAW onto DRG neurons. After 12h co-culturing, we added AGE to the co-culture and stimulated RAW. A DRG neuronal mono-culture was treated with 500 nM of insulin receptor antagonist (BMS-754807) , and 20 ng/ml of TNF-α with/without 50 nM JNK inhibitor (SP600125) . Axonal transport was visualized by Lysotracker and captured by time-lapse microscopy. The movements were quantified on kymographs generated from 100 μm axonal segments. AGE induced the M1 phenotype in RAW with elevated expressions of iNOS and TNF-α mRNA, while no effects on DRG neuron were identified. In the co-culture, the frequency of RAT (RAT%) was significantly reduced when RAW was stimulated by AGE compared to naive RAW (p &amp;lt; 0.001) . In the mono-culture, RAT% was significantly reduced when neurons were treated with BMS-7548 and TNFα (vs. control, both p &amp;lt; 0.001) . TNFα stimulation also increased the phosphorylation of JNK in the axons, a major target of TNFα, which was confirmed by immunofluorescence. The reduction of RAT% by TNFα was rescued by SP600125. In summary, RAT could be impaired by TNF-α and IR, which suggests inflammation induced by M1 in SN can attenuate RAT, which contributes to the DPN pathology. Disclosure S.Osonoi: None. H.Mizukami: None. S.Ogasawara: None. K.Kudoh: None. M.Daimon: None. S.Yagihashi: None. Funding Japan Society for the Promotion of Science (18K16220)

MLKL Regulates Rapid Cell Death-independent HMGB1 Release in RSV Infected Airway Epithelial Cells.

Respiratory syncytial virus (RSV)-induced bronchiolitis is a significant contributor to infant morbidity and mortality. Previously, we identified that necroptosis, a pro-inflammatory form of cell death mediated by receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and RIPK3, and mixed lineage kinase domain like protein (MLKL), occurs in RSV-infected human airway epithelial cells (hAECs), mediating the release of the alarmin high mobility group box 1 (HMGB1). Here, we show that RSV infection of hAECs induces the biphasic release of HMGB1 at 6 (“early”) and 24 (“late”) hours post infection (hpi). The early phase of HMGB1 release at 6 hpi is cell death-independent, however, this release is nonetheless attenuated by inhibition of MLKL (primarily associated with necroptosis). The early release of HMGB1 promotes the late phase of HMGB1 release via the activation of RAGE (receptor for advanced glycation endproducts) and occurs with cell death. Treatment of hAECS with exogenous HMGB1 combined with a pan-caspase inhibitor induces hAEC necroptosis, and is attenuated by the RAGE antagonist, FPS-ZM1. Together, these findings demonstrate that RSV infection of hAECs leads to the early release of HMGB1, followed by a paracrine feed-forward amplification loop that further increases HMGB1 levels and promotes cell death. As the inhibition of MLKL or targeting of HMGB1/RAGE pathway attenuates the release of pro-inflammatory HMGB1 and decreases viral load, this suggests that the pharmacological targeting of these pathways may be of benefit for the treatment of severe RSV bronchiolitis.

Identification of the active compounds and functional mechanisms of Jinshui Huanxian formula in pulmonary fibrosis by integrating serum pharmacochemistry with network pharmacology

BackgroundJinshui Huanxian formula (JHF), a traditional Chinese medicine (TCM), has been demonstrated to attenuate idiopathic pulmonary fibrosis (IPF). The active compounds and underlying mechanisms of JHF, however, are unclear. PurposeThe purpose of This study was to aimed to identify the active compounds and pharmacological mechanism of JHF by integrating serum pharmacochemistry with a network pharmacology strategy. MethodsJHF was orally administered to a rat model with bleomycin (BLM)-induced pulmonary fibrosis (PF). The pharmacodynamic effects and compounds present in the serum were identified. The targets and biological mechanisms of these compounds were revealed using network analysis and validated using in vitro experiments. ResultsJHF could significantly ameliorate BLM-induced PF by preventing extracellular matrix collagen deposition. Twenty-seven compounds that were found to be enriched in the serum samples collected 1 h after oral administration with JHF were identified as the candidate active compounds, and their 423 potential targets were identified as JHF targets. primarily related to the advanced glycation and products-receptor for advanced glycation end products (AGE-RAGE) signaling pathway, phosphatidylinositol 3 kinase (PI3K)-protein kinase B (PKB or AKT) signaling pathway, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance, etc. The 423 targets, 1145 IPF-related genes and their overlapped genes were applied to analyze, respectively. The results showed that these genes were primarily related to the advanced glycation end-products–receptor for advanced glycation end-products (AGE–RAGE) signaling pathway, lipid and atherosclerosis pathology, phosphatidylinositol 3 kinase (PI3K)-protein kinase B (PKB or AKT) signaling pathway, and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor resistance. Furthermore, the affinity between serum JHF compounds and the main proteins in the above important pathways was investigated through molecular docking. As a result, Molecular docking analysis showed that, tangeretin, isosinensetin, and peimine were found to could bind to EGFR and AKT, and their inhibitory effect on EGFR and AKT were validated in fibroblast cell induced by transforming growth factor (TGF)TGF-β. The results indicated that suppression of fibroblast activation by inhibiting the EGFR/PI3K/AKT signaling pathway might be an important mechanism of JHF may to treat PF. ConclusionJHF may suppress fibroblast activation by inhibiting the EGFR/PI3K/AKT signaling pathway to ameliorate PF. Tangeretin, isosinensetin, and peimine may be the active compounds in JHF involved in the treatment of that have therapeutic effects on IPF.

Matrine inhibits advanced glycation end products-induced macrophage M1 polarization by reducing DNMT3a/b-mediated DNA methylation of GPX1 promoter

Advanced glycation end products (AGEs) are characterized diabetic metabolites inducing macrophage M1 polarization which is crucial in diabetes-exacerbated atherosclerosis. Matrine was proved anti-atherosclerotic. The current study was aimed to investigate the inhibitory effects of matrine on AGEs- induced macrophage M1 polarization and underlying molecular mechanisms. Primary mouse macrophages were exposed to AGEs. Receptor for AGEs (RAGE) and toll-like receptor 4 (TLR4) were over-expressed by vectors. Matrine was used to treat these cells. Inducible nitric oxide synthase (iNOS) expression and pro-inflammatory cytokine production were used to evaluate macrophage M1 polarization. Oxidative stress was assessed by intracellular reactive oxygen species (ROS) generation, total antioxidant capacity (TAC) and malondialdehyde (MDA) contents. Relative mRNA expression level was determined by real-time PCR. Western blotting was used to evaluate protein and protein phosphorylation levels. Bisulfite sequencing PCR (BSP) was used to evaluate DNA methylation. Matrine reduced AGEs exposure-elevated expressions of DNA methyltransferase (DNA MTase, DNMT)3a and DNMT3b in macrophages which were not affected by RAGE or TLR4 over expressions. DNA methylation rate of GPX1 promoter was reduced from 97.22% to 66.67% in AGEs- exposed macrophages treated by matrine. GPX1 expression was up-regulated by matrine, which further suppressed AGEs/RAGE-mediated oxidative stress. Thus, the activation of down-stream TLR4/STAT1 signaling pathway was inhibited by matrine treatment which eventually suppressed AGEs- induced macrophage M1 polarization. However, these effects of matrine were impaired by RAGE and TLR4 overexpression. Results from this study suggested that matrine inhibited AGEs- induced macrophage M1 polarization by suppressing RAGE-induced oxidative stress-mediated TLR4/STAT1 signaling pathway. Matrine exerted anti-oxidant effects via increasing GPX1 expression by inhibiting DNMT3a/b-induced GPX1 promoter DNA methylation.