Advanced glycation end products consumption and the decline of functional capacity in patients with Parkinson's disease: Cross-sectional study

Abstract Introduction Advanced Glycation End-Products (AGEs) are a diverse group of highly reactive molecules that play a vital role in the development of neurodegenerative disorders, such as Parkinson's Disease (PD), leading to a decline in functional and cognitive capacity. The objective of this study was to assess the intake and quantification of AGEs in individuals with PD and to correlate them with their functional and cognitive abilities. Methods This was a cross-sectional study involving 20 PD patients and 20 non-PD individuals as the Control group (C). The autofluorescence reader was used to evaluate skin AGEs, while food recall was used to quantify AGEs consumed for three different days. The Montreal Cognitive Assessment, Short Physical Performance Battery, and handgrip tests were used. PD patients demonstrated greater impairment in functional capacity compared to the control group. Results Dominant Handgrip (p = 0.02) and motor performance, in the sit and stand test (p = 0.01) and Short Physical Performance Battery (SPPB) (p = 0.01) were inferior in PD patients than the control group. Although PD patients tended to consume less AGEs than the control group, AGE intake was negatively correlated with handgrip strength in individuals with PD (r = -0.59; p < 0.05). Conclusion PD patients had lower strength and functional capacity, suggesting that the effects of AGEs might be exacerbated during chronic diseases like Parkinson's.

Existence of advanced glycation / lipoxidation end-products in parenteral nutrition solutions and effects of infusion conditions on their levels

Abstract Infusion solutions must be stable from the production stage until the infusion stage. Some infusion fluids contain degradation products, known as advanced glycation end products (AGEs); however, it is unknown whether AGEs exist in parenteral nutrition solutions. We aimed to investigate this question and test the effect of infusion conditions on AGE formation in parenteral nutrition solution. Nine parenteral nutrition solutions were supplied by the pharmacy with which we collaborated. To simulate the infusion conditions, the solutions were held in a patient room with standard lighting and temperature for 24 hours. Samples were taken at the beginning (group A) and the end (24th hour, group B) of the infusion period. The degradation products were 3-deoxyglucosone, pentosidine, N-carboxymethyl lysine, and 4-hydroxynonenal, which we investigated by high-performance liquid chromatography-mass spectrometry (LC-MS) and Q-TOF LC/MS methods. Two of four degradation products, 4-hydroxynonenal and N-carboxymethyl lysine, were detected in all samples, and Group B had higher levels of both compounds compared to Group A, who showed that the quantities of these compounds increased in room conditions over time. The increase was significant for 4-hydroxynonenal (p=0.03), but not for N-carboxymethyl lysine (p=0.23). Moreover, we detected in the parenteral nutrition solutions a compound that could have been 4-hydroxy-2-butynal or furanone

Changes of RAGE/p38MAPK/NF-κB signaling pathway in brain tissue of subchronic fluorosis rats and protective effects of Ginkgo biloba extract and RAGE antagonist / 环境与职业医学

Background Fluorine accumulates in the brain tissue after long-term excessive intake and subsequently cause nerve damage and decline of learning and memory ability. Receptor of advanced glycation end-products (RAGE)/p38 mitogen-activated protein kinase (p38MAPK)/nuclear factor kappa-B (NF-κB) signaling pathway is considered to be involved in the associated mechanism. Objective To study the changes of RAGE/ p38MAPK/ NF-κB signaling pathway in rats with subchronic fluorosis, and to explore the protective effects of extract of Ginkgo biloba 761 (EGb761) and RAGE antagonist (FPS-ZM1) on neuromemory ability. Methods Ninety male clean SD rats were divided into 9 groups with 10 rats in each group. The modeling period was 6 months. Control group (C group): free drinking tap water (fluoride content <0.5 mg·L−1), low- and high-dose fluoride groups (LF group, HF group): free drinking tap water with 10 or 50 mg·L−1 fluoride; intervention group of Ginkgo biloba extract (CE, LFE, and HFE groups): on the basis of the C group, LF group, and HF group, 100 mg·kg−1·d−1 EGb761 was given daily via intragastric administration; FPS-ZM1 intervention groups (CF, LFF, and HFF groups): 7 d before the end of modeling, 1 mg·kg−1·d−1 FPS-ZM1 was injected intraperitoneally daily on the basis of the C group, LF group, and HF group. The contents of fluoride in brain and blood of each group were detected. The learning and memory ability was tested by water maze experiment. The histopathologic changes of the hippocampus were detected by Nissl staining. The protein expression levels of RAGE and its ligand high mobility group protein B1 (HMGB1), NF-κB, p38MAPK, phospho-p38MAPK (p-p38MAPK), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α) in brain tissue were detected by Western blotting. The mRNA expression levels of RAGE, HMGB1, and p38MAPK were detected by quantitative real-time PCR. Results Compared with the C group, the contents of blood fluoride and brain fluoride in the LF and the HF groups were increased (P<0.05). The results of the water maze experiment showed that, compared with the C group, the escape latency time of the LF group and the HF group was longer and the crossing times were reduced; compared with the HF group, the escape latency time of the HFE group and the HFF group was shortened, and the crossing times were increased (P<0.05). The Nissl staining results showed that the number of Nissl body in the HF group decreased compared with the C group; compared with the HF group, the number of Nissl body in the HFE group and the HFF group increased. The Western blotting results showed that compared with the relative protein expression levels of RAGE, HMGB1, NF-κB, p38MAPK, p-p38MAPK, IL-6, and TNF-α in the C group , the levels of above indicators in the HF group and the levels of RAGE, HMGB1, NF-κB, p-p38MAPK, and IL-6 in the LF group were up-regulated (P<0.05); compared with the HF group, the levels of above indicators in the HFE group and the HFF group were all down-regulated (P<0.05); compared with the relative protein expression levels of RAGE and HMGB1 in the LF group, the levels in the LFE group and the LFF group were all down-regulated (P<0.05). The quantitative real-time PCR results showed that compared with the C group, the mRNA expression levels of RAGE and HMGB1 in the LF group and the HF group were up-regulated; compared with the LF group, the mRNA expression levels of RAGE in the LFE group and the LFF group were down-regulated ; compared with the HF group, the mRNA expression levels of RAGE and HMGB1 in the HFE group and the HFF group were down-regulated (P<0.05). Conclusion The central nervous system injury caused by subchronic fluorosis may be related to the activation of RAGE/p38-MAPK/NF-κB signaling pathway, which can impair the learning and memory ability of rats, while EGb761 and FPS-ZM1 may have certain protective effects on the nerve injury.

Protective Mechanism of Youguiwan through AOPPs Regulating RAGE/ROS/NF-κB Axis and Wnt/β-catenin Signal in Rats with Adriamycin-induced Nephrotic Syndrome / 中国实验方剂学杂志

ObjectiveTo explore the effect of Youguiwan on the rats with adriamycin-induced nephrotic syndrome （NS） and its mechanism. MethodSD rats were randomly divided into a normal group， a model group， three Youguiwan low， medium， and high-dose groups， and a prednisone group. Rats in the model group were intravenously injected with adriamycin in the tail vein to induce the NS model. Rats in the Youguiwan low， medium， and high-dose groups were given 2.8， 5.6， 11.2 g·kg-1·d-1 of crude drugs， respectively， and rats in the prednisone group were given 6.3 mg·kg-1·d-1 of prednisone acetate. Each administration group was given continuous medicine for 6 weeks， and the normal group and model group were given an equal volume of normal saline. Bicinchoninic acid （BCA） assay was used to detect 24 h urine protein （24 h UP）. Automatic biochemical analyzer was used to detect serum urea nitrogen （BUN）， creatinine （SCr）， albumin （ALB）， total cholesterol （TC）， and triglyceride （TG） levels. Hematoxylin-eosin （HE） staining was used to observe renal tissue morphology， and kit was used to detect serum advanced oxidized protein products （AOPPs） and reactive oxygen species （ROS）. Western blot was used to detect the receptor of advanced glycation endproducts （RAGE） of renal tissue， nuclear factor-κB （NF-κB） phosphorylation levels， Wnt， and β-catenin protein expression. ResultAs compared with the normal group， 24 h UP， serum BUN， SCr， TC， TG， AOPPs， and ROS levels in the model group increased significantly （P<0.01）， whereas ALB decreased （P<0.01）. There were typical pathological injuries in the renal tissue， and the expressions of RAGE， phosphorylation（p）-NF-κB， Wnt1， and β-catenin protein were significantly increased （P<0.01）. As compared with the model group， the 24 h UP， serum BUN， SCr， TC， TG， AOPPs， and ROS levels of rats in the Youguiwan low， medium， and high-dose groups significantly reduced （P<0.01）， and ALB significantly increased （P<0.01）. The renal tissue damage was reduced， and the expressions of RAGE， p-NF-κB， Wnt1， and β-catenin protein were significantly decreased （P<0.01） in a dose-dependent manner. ConclusionYouguiwan improves the kidney injury of rats with adriamycin-induced NS. The mechanism may be related to the reduction of AOPPs level， inhibition of RAGE/ROS/NF-κB axis， and activation of Wnt/β-catenin signal.

Ferroptosis is essential for diabetic cardiomyopathy and is prevented by sulforaphane via AMPK/NRF2 pathways

Herein, we define the role of ferroptosis in the pathogenesis of diabetic cardiomyopathy (DCM) by examining the expression of key regulators of ferroptosis in mice with DCM and a new ex vivo DCM model. Advanced glycation end-products (AGEs), an important pathogenic factor of DCM, were found to induce ferroptosis in engineered cardiac tissues (ECTs), as reflected through increased levels of Ptgs2 and lipid peroxides and decreased ferritin and SLC7A11 levels. Typical morphological changes of ferroptosis in cardiomyocytes were observed using transmission electron microscopy. Inhibition of ferroptosis with ferrostatin-1 and deferoxamine prevented AGE-induced ECT remodeling and dysfunction. Ferroptosis was also evidenced in the heart of type 2 diabetic mice with DCM. Inhibition of ferroptosis by liproxstatin-1 prevented the development of diastolic dysfunction at 3 months after the onset of diabetes. Nuclear factor erythroid 2-related factor 2 (NRF2) activated by sulforaphane inhibited cardiac cell ferroptosis in both AGE-treated ECTs and hearts of DCM mice by upregulating ferritin and SLC7A11 levels. The protective effect of sulforaphane on ferroptosis was AMP-activated protein kinase (AMPK)-dependent. These findings suggest that ferroptosis plays an essential role in the pathogenesis of DCM; sulforaphane prevents ferroptosis and associated pathogenesis via AMPK-mediated NRF2 activation. This suggests a feasible therapeutic approach with sulforaphane to clinically prevent ferroptosis and DCM.

Soluble receptor for advanced glycation end-products inhibits myocardial fibrosis of ischemia/reperfusion mice / 解剖学报

Objective To investigate the effect of soluble receptor for advanced glycation end-products (sRAGE) on inflammation in myocardial ischemia/reperfusion ( I/R ) mice and its mechanism. Methods Myocardial I/R injury model was conducted by left anterior descending ligation for 30 minutes and reperfusion for 2 weeks in male C57BL/6 mice aged 6-8 weeks. The mice were randomly divided into four groups with five C57BL/6 mice in each group. The cardiac function was detected by echocardiography, the inflammatory cells infiltration was observed by HE staining, the myocardial fibrosis was detected by Masson and Sirius red staining, the expression of galectin-3 was detected by immunohistochemical staining. Results Compared with the sham group, the cardiac function decreased, the inflammatory cells infiltrated increased among the myocardial tissue, the percentage of myocardial fibrosis area increased, and the expression of galectin-3 increased in I/R groups. After exogenous sRAGE treatment, the cardiac function of mice was significantly improved, the inflammatory cells infiltration decreased, the myocardial fibrosis area decreased, and the expression of galectin-3 decreased as well. Conclusion sRAGE may reduce inflammatory cells infiltration in mice heart by inhibiting the expression of galectin-3, and then alleviating myocardial fibrosis during myocardial ischemia/reperfusion injury.

Progress in Advanced Glycation End-Products Effects on Biomechanics of Bone Tissues / 医用生物力学

Advanced glycation end-products (AGEs) are the products of non-enzymatic reactions between free amino groups of macromolecules and reducing sugars. AGEs accumulation in bone tissues changes the activity and function of bone cells by binding to their surface receptors, causing abnormalities in the process of bone remodeling. AGEs accumulation can also change the original structure and mineral deposition of bone collagen, affect the micro-mechanical properties of bone tissues, and further reduce bone strength and toughness, increase the bone fracture risk, which will lead to bone diseases and do great harm to human health. This article summarized the causes of AGEs and their detection methods, and reviewed previous studies about the effects of AGEs accumulation on bone biomechanics at micro and macro levels, so as to provide references for the early diagnosis and treatment of bone diseases in clinic.

Effect of Huangqi Guizhi Wuwutang on AGEs/RAGE/NF-κB Signaling Pathway in Diabetic Peripheral Neuropathy Rats / 中国实验方剂学杂志

Objective:To study the effect of Huangqi Guizhi Wuwutang on receptor of advanced glycation end products(AGEs)/advanced glycation endproducts (RAGE)/nuclear transcription factor-kappa B p65 (NF-κB p65) signaling pathway in the diabetic peripheral neuropathy rats through an animal modeling experiment, and discuss the mechanism of Huangqi Guizhi Wuwutang in alleviating diabetic peripheral neuropathy. Method:Rat model of diabetic peripheral neuropathy was established by high-fat diet and intraperitoneal injection with streptozotocin (STZ). After successful modeling, Huangqi Guizhi Wuwutang intervention began in the fifth week. The patients in high-dose group (19.40 g∙kg-1∙d-1), middle-dose group (4.85 g∙kg-1∙d-1) and low-dose group (2.43 g∙kg-1∙d-1) were given by gavage continuously for 12 weeks. The western medicine control group was given 25 mg∙kg-1∙d-1 by gavage. After the experiment, serum interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). Real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) was used to detect RAGE and NF-κB p65 mRNA expressions in sciatic nerve tissue. The expressions of RAGE, NF-κB and phosphorylation(p)-NF-κB p65 proteins in sciatic nerve tissues were detected by Western blot (WB). Result:Compared with the normal group, serum IL-1β and TNF-α protein levels, RAGE mRNA and NF-κB p65 mRNA levels, RAGE protein, NF-κB p65 protein and p-NF-κB p65 protein levels were significantly increased in the model group (P<0.01), the ratio of p-NF-κB p65 to NF-κB p65 was increased, and the phosphorylation of NF-κB p65 was enhanced (P<0.01). After the intervention of Huangqi Guizhi Wuwutang, compared with the model group, serum IL-1β and TNF-α protein levels, RAGE and NF-κB p65 mRNA levels, RAGE protein, NF-κB p65 protein and p-NF-κB p65 protein levels were all decreased (P<0.01), the ratio of p-NF-κB p65 to NF-κB p65 was decreased in high-dose group (P<0.01). The effect was obvious with the increase of dose of astragalus cassia twig. Conclusion:Huangqi Guizhi Wuwutang can alleviate diabetic peripheral neuropathy, and its mechanism may be related to blocking the expression of RAGE on tissue cell surface in AGEs/RAGE/NF-κB signaling pathway, inhibiting the activation of NF-κB and inducing TNF-α triggered oxidative stress and excessive inflammatory response, so as to avoid cell damage and dysfunction.

Effect of Betulic Acid on RAGE/NF-κB/iNOS Signaling Pathway Expression in Steatosis Cell / 中国实验方剂学杂志

Objective::To investigate the effect of betulic acid(BA) on steatosis LO2 cells. Method::LO2 cells were intervened with BA at different gradient concentrations (0, 10, 20, 40, 80, 160, 250 μmol·L-1) for 24 hours. methyl thiazolyl tetrazolium(MTT) staining was used to observed cell viability to determine the final concentration of BA. The cells were divided into control, model, dimethylsulfoxide (DMSO) and BA groups, as well as BA groups intervened with low, middle and high concentrations. First, model, DMSO and BA group's cells were cultured in 10% Lipid Mix 1 medium for 24 hours to establish a nonalcoholic fatty liver model. Then, DMSO group and low, medium and high-concentration groups were separately cultured with 0.1%DMSO medium and 20, 40, 80 μmol·L-1 BA medium for 24 hours. And control and model groups were cultured in drug-free medium for 24 hours. Oil red O staining and Nile red staining were used to observe the intracellular lipid droplets. Immunofluorescence was used to detect the protein expression of inducible nitric oxide synthase (iNOS). Western blot was used to detect the protein expression levels of receptor for advanced glycation end-products (RAGE), nuclear factor κB p65 (NF-κB p55) and iNOS. Result::BA within the concentration of 80 μmol·L-1 had no significant toxicity on LO2 cells. Compared with control group, the intracellular lipid droplets were significantly increased in the model group, and the expressions of oxidative stress-related proteins RAGE, NF-κB p65 and iNOS also increased significantly(P<0.05). Compared with model group, the intracellular lipid droplets in DMSO group were similar to those in model group, with no significant difference in the three protein expressions between the two groups. However, the intracellular lipid droplets deposition in the BA group was significantly decreased. And the expressions of RAGE, NF-κB p65 and iNOS proteins in high-concentration BA group were significantly decreased(P<0.05, P<0.01). Conclusion::BA can significantly improve the intracellular fat deposition in LO2 cells, which was probably related to the inhibition of the expressions of oxidative stress-related proteins RAGE, NF-κB p65 and iNOS.

Study on formation regularity and kinetics of advanced glycation end-products during processing of boiled Cervi Cornu Pantotrichum / 中草药

Objective: To study the formation regularity and kinetic parameters of advanced glycation end-products during the processing of boiled Cervi Cornu Pantotrichum (CCP). Methods: UV-visible spectrophotometry and UPLC-MS/MS method were used to determine the change of browning index and content of typical advanced glycation end-products, Nε-(carboxymethyl) lysine and Nε-(carboxyethyl) lysine, of the processing system of simulated boiled CCP. The formation regularity and kinetic parameters of advanced glycation end-products during the processing of boiled CCP were discussed by constructing glucose and lysine to simulate the Maillard reaction system of CCP processing. Results: The activation energy of browning reaction, Nε-(carboxymethyl) lysine and Nε-(carboxyethyl) lysine reaction during processing of boiled CCP were 5.07, 40.44 and 78.47 kJ/mol, respectively, and all of them were zero-order kinetics. The activation energies of the above reactions in the baking process were 6.72, 89.34 and 164.77 kJ/mol, respectively, and all of them were zero-order kinetics. Compared to the formation of Nε-(carboxymethyl) lysine, the formation of Nε-(carboxyethyl) lysine required higher activation energy and was more difficult to occur. Conclusion: The temperature changed in the baking process has a significantly higher effect on the kinetic parameters of the advanced glycation end-products than in the boiling process. Long-term higher baking temperature resulted in more advanced glycation end-products produced in the boiled CCP. This study provides a solid theoretical basis for the blocking and inhibition strategies of advanced glycation end-products in the processing of CCP, which is also a great significance for the production of green safety CCP and strengthening the safety of traditional Chinese medicine.

Effect and mechanisms of pioglitazone on post operative cognitive function induced by surgery in elderly rats / 临床麻醉学杂志

Objective To investigate the effect and mechanisms of pioglitazone on post operative cognitive function induced by surgery in elderly rats.Methods Elderly SD rats,male and weighing 220-250 g,were randomly divided into control group (group Con),surgery group (group S),pioglitazone group (group P)and pioglitazone/surgery group (group PS).The level of glycemia was measured by glucometer after completing the surgical model.The expression of advanced glycation endproducts (AGEs)in hippocampal tissues was detected by western blot and reactive oxy-gen species (ROS)and IL-6 by ELISA 1 2 h after surgery.Morris water maze was used for evaluation of cognitive function 4 days after surgery.Results Compared with group Con,group S showed a sig-nificant increase in the expression of AGEs and IL-6 and the level of ROS (P<0.05);Compared with group S,the expression of AGEs and IL-6 and the level of ROS decreased significantly in group PS (P<0.05).Compared to group Con,the surgery increased the average time of escape latencies on the 8th days and 10th days after surgery and reduced the platform-crossing times in the Morris water maze test (P<0.05).Compared with group S,group PS showed a significant decrease in the average time of escaping latencies on the 10th day after surgery (P<0.05),and an increased platform-cross-ing times in the Morris water maze test (P<0.05).Conclusion These results suggest that pioglita-zone attenuates postoperative cognitive function and its mechanism may be related to the decrease of the expression of AGEs and IL-6 and the level of ROS.

The role of RAGE in high mobility group box-1 protein1-mediated CD4+T cells differentiation to Th1/Th2 / 中华急诊医学杂志

Objective To explore the role of receptor for advanced glycation end products (RAGE) in HMGBl-mediated CD4+ T cells differentiation to Th1/Th2.Methods CD4+ T lymphocytes isolated from the spleens of male BALB/C mice by magnetic beads were suspended in RPMI-1640 with 10％ FCS in 2× 106cell/well on 96-well cell culture plates in vitro.The cells were randomly divided 4 groups according to concentration of HMGB1 treatment:control group,10 ng/mL group,100 ng/mL group,1 000 ng/mL group after stimulation with ConA in 3 μg/mL for 12 hours.IL-4 and IFN-γ levels in culture supernatants were quantitated by ELISA kits after HMGB1 stimulation for 12,24,and 48 h.According to the results,cultured cells were exposed to HMGB1 in 100 ng/mL for 24 h in the following experiments.The cells were randomly divided into 4 groups:control group,A group,B group,C group,and each group were cultured with ConA in 3 μg/mL for 24 h.The cells of control group and other three groups were stimulated with PBS or 100 μg/L HMGB1 for 24 h.The cells of B,C groups were incubated with 1/200 diluted 5 μg/L anti-RAGE Abs (anti-bodies) or PBS for 2 h before HMGB1 stimulation.The cell suspension was obtained to detect the levels of IL-4 and IFN-γ by EILSA and the protein levels and mRNA expressions of RAGE,CATA-3 were detected by western-blot and real-time fluorescent quantitative PCR,respectively.ResuRs Compared with control group,CD4+ T cells incubated with increasing concentrations of HMGB1 (100,1 000 ng/mL) for 24 h resulted in a decrease in IFN-γ/IL-4 ratio (P＜0.05).When CD4+ T cells were exposed to 100 ng/mL HMGB1 for 12 h,IFN-γ/IL-4 ratio was markedly increased.However,CD4+ T cells treated with 100 ng/mL HMGB1 for 24,48 h,IFN-γ/IL-4 ratio was markedly inhibited (P＜0.05).Compared with control group,protein levels and mRNA expressions of RAGE and GATA3 of cells in A group were significantly increased (P＜0.05),and IFN-γ/IL-4 ratio of cell suspension in A group and B group was significantly down-regulated (P＜0.05).Compared with A group,IFN-γ/IL-4 ratio of cell suspension in C group was increased (P＜0.05),and expression of GATA3 mRNA was down-regulated (P＜0.05).Compared with A group,protein level of RAGE of cells in C group was significantly down-regulated (P＜0.05),but protein level of RAGE of cells in C group was still increased compared with control group (P＜0.05).Conclusion Th1/Th2 differentiation induced by HMGB1 on CD4+ T lymphocytes in vitro was at least partly mediated by over-activating RAGE/GATA3 pathway.

Research progress in skin advanced glycation end-products and diabetic kidney disease / 中国糖尿病杂志

Diabetic kidney disease(DKD) is one of the major complications of diabetes mellitus.The formation of advanced glycationend-products (Advanced Glycation End-products,AGEs) has been widely accepted to play a crucial role in the pathogenesis of diabetic nephropathy.It has been reported that the skin autofluorescence test of AGEs can better reflect the AGEs accumulation in vivo,thus providing stronger evidence in predicting diabetic nephropathy.As a noninvasive,convenient and steady measure,skin autofluorescence will be widely applied in the assessment and monitoring the progress of diabetic nephropathy in the future.Here,we reviewed the research progress in skin AGEs and diabetic nephropathy.

S100A8 inhibits PDGF-induced proliferation of airway smooth muscle cells dependent on the receptor for advanced glycation end-products

BACKGROUND: Airway remodeling is a key feature of asthma, characterized by increased proliferation of airway smooth muscle cells (ASMCs). S100A8 is a calcium-binding protein with a potential to regulate cell proliferation. Here, the effect of exogenous S100A8 protein on the proliferation of ASMCs induced by platelet-derived growth factor (PDGF) and the underlying molecular mechanism was investigated. METHODS: Rat ASMCs were cultured with or without a neutralizing antibody to the receptor for advanced glycation end-products (RAGE), a potential receptor for S100A8 protein. Purified recombinant rat S100A8 protein was then added into the cultured cells, and the proliferation of ASMCs induced by PDGF was detected by colorimetric-based WST-8 assay and ampedance-based xCELLigence proliferation assay. The expression levels of RAGE in ASMCs were analyzed using western blotting assay. RESULTS: Results showed that exogenous S100A8 inhibited the PDGF-induced proliferation of rat ASMCs in a dose- dependent manner with the maximal effect at 1 µg/ml in vitro. Furthermore, when ASMCs was pre-treated with anti-RAGE neutralizing antibody, the inhibitory effect of S100A8 on PDGF-induced proliferation was significantly suppressed. In addition, neither the treatment with S100A8 or PDGF alone nor the pre-treatment with rS100A8 followed by PDGF stimulation affected the expression levels of RAGE. CONCLUSIONS: Our study demonstrated that S100A8 inhibits PDGF-induced ASMCs proliferation in a manner dependent on membrane receptor RAGE.

Advanced glycation end products and its receptor induce apoptosis of L cells through NADPH oxidase mediated signaling pathway / 实用医学杂志

Objective To investigate the effects of AGEs-RAGE on the apoptosis of GLUTag cells and explore the possiblc mechanism.Methods GLUTag cells treated with 0、100、200、300μg/ml of AGEs for 24h were examined for gene and protein expression of RAGE using RT-PCR and western blotting,respectively.GLUTag cells were randomly divided into four groups:control,200μg/ml AGEs,AGEs+siRNA-RAGE and AGEs+apocynin.The protein expression of p22phox、p47phox 、Bcl-2、Bax in the cells were detected with western blotting.The reactive oxygen species (ROS) levels were examined using 2'7'-dichlorodihydroflur-rescein diacetate (DCFH-DA) and the apoptosis of L cells were tested by AnnexinV-FITC/PI.Results AGEs increased thc cxpression of RAGE in a dose dependent manner.Treatment with AGEs induced a significant increase in the expression of p22phox,p47phoxand the activity of ROS,caused up-regulation of Bax and down-regulation of Bcl-2,which enhanced the apoptosis of GLUTag cells.Apocynin,the inhibitor of NADPH oxidase,prevented those responses and the effects caused by AGEs were abolished by inhibition of RAGE activity with siRNA.Conclusion AGEs positively regulate the exprcssion of NADPH oxidase-derived ROS and its down-steam signaling pathway p53/Bax by targeting RAGE,leading to the apoptosis of GLUTag cells.

Retracted: Skin Expression of Advanced Glycation End Products (AGEs), Their Receptor (RAGE) and Glyoxalase-I (GLO-I) in Patients with Diabetic Neuropathy.

Advanced Glycation End Products (AGEs), their receptor (RAGE) and their detoxifying enzyme Glyoxalase-I (GLO-I) have been implicated in the development of experimental diabetic peripheral neuropathy (DPN). However, few studies have assessed their role in the tissues of diabetic patients. We have assessed the relationship between skin expression of AGEs, RAGE, GLO-I and diabetic neuropathy in patients with type 1 diabetes. Sixty-two patients with type 1 diabetes mellitus (16 with and 46 without DPN) and 30 age-matched control subjects underwent detailed assessment of neurologic deficits, quantitative sensory testing, electrophysiology, corneal confocal microscopy (CCM), intraepidermal nerve fibre density (IENFD) and AGEs, RAGE and GLO1-I expression in foot skin biopsies. Skin AGEs and RAGE expression was significantly higher and GLO-I was significantly lower in the 16 epidermis, microvessels and reticular extracellular matrix of patients with diabeticneuropathy as compared to diabetic patients without neuropathy and control subjects. Skin AGEs and RAGE expression was also moderately but significantly increased and GLO-I expression was decreased in some skin structures in patients without diabetic neuropathy as compared to control subjects. Skin AGEs and RAGE expression correlated negatively and GLO-I expression correlated positively with sural nerve amplitude and velocity, IENFD and corneal nerve pathology. These findings suggest that AGEs, RAGE and GLO-I may play an important role in the etiology of human diabetic neuropathy. Retraction Notice: This paper has been retracted from the journal after receipt of written complains regarding authorship dispute. This journal is determined to promote integrity in research publication. This retraction is in spirit of the same. After formal procedures editor(s) and publisher have retracted this paper on 5th April-2016. Related policy is available here: http://goo.gl/lI77Nn

Effect of block of AGEs-RAGE pathway on the migration of VSMCs / 中国药科大学学报

@#To investigate the effect of block of AGEs-RAGE pathway on the migration of aortic vascular smooth muscle in diabetic rats and its possible mechanisms, vascular smooth muscle cells(VSMCs)cells were pre-stimulated by antibody of RAGE, and then stimulated by AGEs. Transwell assay was adopted to assay migration of VSMCs. Proliferation of VSMCs and expression of p27 were analyzed by MTT and ELISA, respectively. The change of ROS level in VSMCs was defermined by DCFH assay, the expression of NOX1 mRNA was determined by RT-PCR assay. Results indicated that the AGEs induction for migration of VSMCs was significantly inhibited after treatment by RAGE antibody(P< 0. 01), which blocked the AGEs-RAGE pathway, and the inhibition of migration was stronger than that of proliferation. The ROS level was decreased(P< 0. 01), and the expression of NOX1 mRNA was decreased, yet the expression of P27 protein was not changed greatly. Block of AGEs-RAGE pathway by antibody of RAGE can inhibit the migration of VSMCs, and the mechanism may be related with the decrease of NOX1 mRNA and then down to the level of intracellular oxidative stress in VSMCs.

Research progress on transport mechanism of amyloid beta-peptides across blood-brain barrier / 中国药理学通报

Amyloid beta-peptides ( Aβ) is the key pathological feature of Alzheimer’s Disease (AD). Various factors contrib-ute to the accumulations of Aβ in the brains of patients. Among them, blood-brain barrier ( BBB) plays a crucial role in trans-porting Aβ between the brain and the bloodstream while this transfer function is mediated by the receptor of Aβon BBB. The abnormality of Aβ transport and related receptor expression can be detected in the brains of patients with AD, resulting in an un-usual increase in Aβlevels unusually increased . This review e-laborates the structure and function of BBB, the transport of Aβand the expression and transport mechanism of the related recep-tor, as well as summarizes the possible clearance strategy of Aβacross the BBB.

Study of anti-diabetic nephropathy efficacy of berberine analogue Y53 in STZ-induced diabetic C57 BL/6 J mice / 中国药理学通报

Aim To investigate the ameliorative effects pseudoberberine(Y53), a berberine(BBR) analogue, on diabetic nephropathy( DN) in streptozotocin( STZ)-induced diabetic mice. Methods Diabetes mellitus ( DM) of the C57BL/6J mice was induced by intraper-itoneal injection of STZ at 120 mg·kg-1 . The diabetic animals were divided into 4 groups, which were orally treated with saline, 50 mg · kg-1 of BBR, 50 mg · kg-1 of Y53 or 5 mg · kg-1 of rosiglitazone ( ROSI ) , respectively. During and after the experiment, the u-rine, blood, serum and kidney of the animals were harvested for determination of relevant parameters by kits. Kidney tissues of the mice were subjected to pathological examination by hematoxylin & eosin( HE) staining;mRNA and protein expression levels of target genes in the kidney were determined by quantitative re-al-time reverse transcriptase-polymerase chain reaction ( qRT-PCR) and Western blot, respectively. Results Y53 greatly reduced the fasting blood glucose ( FBG ) and glycosylated hemoglobin( GHb) , improved diabet-ic symptoms such as polyphagia and polyuria in the di-abetic mice( P<0. 01 vs DM control group) . Y53 po-tently reduced the blood urea nitrogen ( BUN ) , serum creatinine( Scr) , 24 h urinary protein, kidney index, serum and kidney advanced glycation end-products ( AGEs) and nitric oxide( NO) , as well as kidney cho-lesterol( CHO ) and triglyceride ( TG ) contents ( P <0. 05 or P<0. 01 vs DM control group) . In the patho-logical examination, Y53 greatly restored kidney mor-phology and suppressed glomerular sclerosis( P<0. 001 vs DM control group). In addition, Y53 significantly reduced the renal expression of fibrosis-related genes, such as the transforming growth factor-β1 ( TGF-β1 ) and smad2(P<0. 01 vs DM control group). The reno-protective efficacies of Y53 were superior to those of BBR and ROSI in our study ( P<0. 05 or P<0. 01 ) . Conclusions The BBR analogue Y53 has potent ac-tivities in ameliorating renal injury and restoring renal function in STZ-induced diabetic mice. Y53 may be developed as a novel kind of agent for the treatment of DN in the future.

Effect of gypenosides on RAGE and TGF-β1 expression in human mesangial cells induced by AGEs / 中国药理学通报

Aim To observe the effect of gypenosides ( GP) on the expression of receptor for advanced gly-cated endproducts ( RAGE ) and transforming growth factor-β1 ( TGF-β1 ) in human mesangial cells( HMCs) induced by AGEs. Methods HMCs were cultured in DMEM of low glucose containing 15% fetal bovine ser-um in vitro, which were divided into four groups: the normal group, model group, GP group and positive control group. In addition to the normal group, the other groups were stimulated by AGEs ( 200 mg · L-1 );furthermore, GP group was intervened with dif-ferent concentrations(25,75,175 mg·L-1) of GP, while control group was given 10 mmol · L-1 of amin-oguanidine hydrochloride. The expression of RAGE and TGF-β1 protein of each group was detected by Western blot; the expression of RAGE and TGF-β1 mRNA of each group was detected by RT-PCR. Re-sults The expression of RAGE, TGF-β1 protein and mRNA in HMCs induced by AGEs in the model group was significantly higher than that of the normal group ( P<0. 01 );compared with the positive control group ( P<0. 01 ) , GP could obviously reduce the expression of RAGE, TGF-β1 protein and mRNA in a dose-de-pendent manner. Conclusion GP can reduce the ex-pression of RAGE in HMCs induced by AGEs, block AGEs-RAGE signaling pathway and decrease the ex-pression of the downstream factor TGF-β1 , therefore, it plays the role in the resistance of rennal fibrosis in DN.