Immunohistochemical distribution of the receptor for advanced glycation end products in neurons and astrocytes in Alzheimer’s disease

Advanced glycation end products (AGE) and the receptor for AGE (RAGE) have been implicated in the chronic complications of diabetes mellitus (DM), and have been reported to play an important role in the pathogenesis of Alzheimer’s disease (AD). In this study, we established a polyclonal anti-RAGE antibody, and examined the immunohistochemical localization of amyloid β protein (Aβ), AGE, and RAGE in neurons and astrocytes from patients with AD and DM. Our anti-RAGE antibody recognized full-length RAGE (50 kd) and N-terminal RAGE (35 kd) in human brain tissue. Aβ-, AGE-, and RAGE-positive granules were identified in the perikaryon of hippocampal neurons (especially from CA3 and CA4) in all subjects. The distribution and staining pattern of these immunopositive granules showed good concordance with each antibody. In AD, most astrocytes contained both AGE-and RAGE-positive granules and their distribution was almost the same. Aβ-positive granules were less common, but Aβ-, AGE-, and RAGE-positive granules were colocalized in one part of a single astrocyte. In DM patients and control cases, AGE-and RAGE-positive astrocytes were very rare. These finding support the hypothesis that glycated Aβ is taken up via RAGE and is degraded through the lysosomal pathway in astrocytes. In addition to the presence of AGE, the process of AGE degradation and receptor-mediated reactions may contribute to neuronal dysfunction and promote the progression of AD.     

血清晚期糖基化终末产物和可溶性晚期糖基化终末产物受体与阿尔茨海默病及血管性痴呆关系的研究

目的探讨血清中晚期糖基化终末产物(AGEs)、可溶性晚期糖基化终末产物受体(sRAGE)的水平与阿尔茨海默病(AD)、血管性痴呆(Va D)的关系。方法收集兰州大学第二医院神经内科2017年2月到2018年1月收治的149例患者,根据MMSE量表及相应的纳入排除标准,将患者进行分组,其中AD组34例,脑梗死后痴呆(Va D)组64例,脑梗死非痴呆(N-Va D)组51例,选择同期在性别、年龄、文化程度上无差异、无严重疾病的住院体检者31例作为正常对照组。比较4组间的一般资料及简易智能精神状态检查量表(MMSE)评分,比较血清AGEs、sRAGE在不同组别之间的差异,并分析其与AD和Va D的关系。结果 AD组和N-Va D组的AGEs水平高于Va D组和正常对照组,差异有统计学意义(P 0. 05)。Va D组和正常对照组之间,AD组和N-Va D组之间的AGEs水平比较,差异无统计学意义(P 0. 05)。ROC曲线分析显示血清AGEs对AD有较低诊断价值。Spearman秩相关法分析显示,年龄(r=-0. 168,P 0. 05)与MMSE评分呈负相关;体重指数(r=0. 151,P 0. 05)与MMSE评分呈正相关。4组在性别、年龄、糖尿病方面不存在显著性差异(P 0. 05)。4组间sRAGE水平比较无显著性差异(P 0. 05)。结论血清AGEs可能与AD的发生、发展有关; AGEs对AD有较低的诊断价值。     

Plasma levels of soluble receptor for advanced glycation end products in Alzheimer's disease

Background: A decreased plasma level of soluble form of the receptor for advanced glycation end products (sRAGE) in patients with Alzheimer's disease (AD) has been reported. However, no evidence has shown whether the sRAGE plasma level of AD patients may differentiate from other types of dementia. Methods: Our study assessed sRAGE concentrations in the following 121 individuals in Chongqing area: 36 patients with AD, 12 with vascular dementia (VaD), 14 with mixed dementia (MD), 24 with other dementia (OD) including Parkinson's disease dementia, frontotemporal dementia, paralytic dementia and 35 cognitively normal controls. The total plasma level of sRAGE was determined using sandwich ELISA method. Results: sRAGE concentration in AD is significantly decreased compared with healthy controls. However, the receiver operating characteristic curve analysis of sRAGE between the AD and the control shows a low diagnostic accuracy. Conclusions: Our results demonstrate that sRAGE may assist the diagnosis of AD from normal individuals, but cannot differentiate AD from VaD, MD or OD.     

Toxic advanced glycation end products (TAGE) theory in Alzheimer's disease

Several epidemiological studies have reported moderately increased risks of Alzheimer's disease (AD) in diabetic patients compared with general population. In diabetes mellitus, the formation and accumulation of advanced glycation end products (AGEs) progress more rapidly. Recent understanding of this process has confirmed that interactions between AGEs and their receptor (RAGE) may play a role in the pathogenesis of diabetic complications and AD. The authors have recently found that glyceraldehyde-derived AGEs (AGE-2), which is predominantly the structure of toxic AGEs (TAGE), show significant toxicity on cortical neuronal cells and that the neurotoxic effect of diabetic serum is completely blocked by neutralizing antibody against the AGE-2 epitope. Moreover, in human AD brains, AGE-2 is distributed in the cytosol of neurons in the hippocampus and parahippocampal gyrus. These results suggest that TAGE is involved in the pathogenesis of AD as well as other age-related diseases. In this review, the authors discuss the molecular mechanisms of AD, especially focusing on TAGE-RAGE system.     

Expression of the receptor for advanced glycation end products in Huntington's disease caudate nucleus

The accumulation of amyloid-beta and increased expression of its receptor RAGE (the receptor for advanced glycation end products) have been implicated in the pathogenesis of Alzheimer's disease (AD). Here we have used immunohistochemistry and double labelling to localize RAGE expression in Huntington's disease (HD) caudate nucleus (CN). Results showed that RAGE is expressed in at least two cell types in the CN, medium spiny projection neurons and astrocytes, with stronger staining in astrocytes than in neurons. The percentage of the total number of neurons positive for RAGE was significantly higher in G2 and G3 HD CN when compared with controls. What is more interesting however was the heterogeneous distribution of RAGE staining in CN. In controls, astrocytic RAGE staining was seen only in the superficial layer of the subependymal layer (SEL). In G1 HD cases, staining was seen throughout the entire width of SEL but extended into the CN in G2, 3 and 4. Neuronal RAGE staining was stronger in the medial CN than in the lateral CN in control and G1 cases. In G2, 3 and 4 cases, this staining gradient was not observed; more neuronal RAGE staining was however seen in the dorsal part of the CN when compared with the ventral part. The distribution of RAGE staining in neurons appeared to correlate with the ordered cell death seen in HD CN. Identification of the ligand for RAGE in HD brain and further functional studies are needed to clarify the role of RAGE in the pathogenesis of HD.     

Analysis of serum of patients with Alzheimer's disease for the level of advanced glycation end products

Data on the serum level of advanced glycation end products (AGEs) in Alzheimer's disease (AD) patients are scarce, although a specific biochemical marker easy to detect in body fluids is desired for an early diagnosis of disease and to monitor the effects of therapeutic treatment. In the current study, the content of AGEs was examined with an immunochemical assay in the sera of AD patients, in the frame of a search for a biochemical marker of disease. Subjects with AD and vascular dementia (VaD) were included in the study (n = 30; age range, 68-70 years). The results were compared to the healthy control groups. The enzyme-linked immunosorbent assay (ELISA) inhibition test for the determination of AGEs is based on a rabbit anti-AGE, affinity-purified antibody and a model AGE-myoglobin antigen, in which a serum sample treated with proteinase K is used as an inhibitor. For the measurement of immune complexes and anti-AGE antibodies, the corresponding ELISA tests have been applied. The AGE level in the VaD group (49.5 U(AGE)) was higher than in AD patients (46.1 U(AGE)). The level of total AGEs in the sera of AD patients was significantly lower than in the control group (50/51.6 U(AGE)). These relations were not observed with regard to the immune complexes and anti-AGE antibody levels in AD (70.2 U(IC)/0.027 U(IgG)) and VaD (83 U(IC)/0.034 U(IgG)) patients because the levels of these parameters were similar to the controls (76.2 U(IC)/0.042 U(IgG)). The work revealed the lower level of circulating serum AGEs in patients with AD in relation to healthy controls.     

Neurotoxicity of acetaldehyde-derived advanced glycation end products for cultured cortical neurons

The Maillard reaction that leads to the formation of advanced glycation end products (AGEs) plays an important role in the pathogenesis of angiopathy in diabetic patients, in aging, and in neurodegenerative processes. We hypothesize that acetaldehyde (AA), one of the main metabolites of alcohol, may be involved in alcohol-induced neurotoxicity in vivo by formation of AA-derived AGEs (AA-AGEs) with brain proteins. Incubation of cortical neurons with AA-AGE produced a dose-dependent increase in neuronal cell-death, and the neurotoxicity of AA-AGE was neutralized by the addition of an anti-AA-AGE-specific antibody, but not by anti-N-ethyllysine (NEL) antibody. The AA-AGE epitope was detected in human brain of alcoholism. We propose that the structural epitope AA-AGE is an important toxic moiety for neuronal cells in alcoholism.     

Lipid peroxidation and advanced glycation end products in the brain in normal aging and in Alzheimer's disease

The cellular distribution of malondialdehyde (MDA) was assessed immunohistochemically in brain specimens from young and normal elderly subjects as well as patients with Alzheimer's disease (AD). MDA was increased in the cytoplasm of neurons and astrocytes in both normal aging and AD, but was rarely detected in normal young subjects. By electron microscopic immunohistochemistry, neuronal MDA formed cap-like linear deposits associated with lipofuscin, while glial MDA deposits surrounded the vacuoles in a linear distribution. In the hippocampus, neuronal and glial MDA deposition was marked in the CA4 region but mild in CA1. By examination of serial sections stained with anti-MDA and antibodies against an advanced glycation end product, N(epsilon)-(carboxymethyl)lysine (CML), neuronal and glial MDA deposition was colocalized with CML in AD, but only neuronal MDA was colocalized with CML in normal aged brains. Glial MDA, although abundant in the aged brain, typically was not colocalized with CML. In AD cases, MDA was colocalized with tau protein in CA2 hippocampal neurons; such colocalization was rare in CA1. MDA also was stained in cores of senile plaques. Thus, while both MDA and CML accumulate under oxidative stress, CML accumulation is largely limited to neurons, in normal aging, while MDA also accumulates in glia. In AD, both MDA and CML are deposited in both astrocytes and neurons.     

Circulating levels of soluble receptor for advanced glycation end products in Alzheimer disease and vascular dementia

BACKGROUND: The receptor for advanced glycation end products (RAGE) is a cell surface receptor that has been implicated in vascular disease and neurodegeneration. Low levels of its secreted isoform, soluble RAGE (sRAGE), have been regarded as a putative risk factor for atherosclerosis. In addition, administration of sRAGE has been shown to reduce development of cerebral beta-amyloidosis in an Alzheimer disease mouse model. OBJECTIVE: To investigate the role of sRAGE as a biological marker for Alzheimer disease and vascular dementia. DESIGN: Cross-sectional study of 152 patients with a clinical diagnosis of Alzheimer disease, 91 with vascular dementia and 161 control subjects. MAIN OUTCOME MEASURE: Plasma levels of sRAGE. RESULTS: Levels of sRAGE were significantly reduced in the plasma of patients with Alzheimer disease compared with that for those with either vascular dementia (P<.05) or with controls (P<.001). CONCLUSIONS: Patients with Alzheimer disease have reduced levels of sRAGE in plasma compared with patients with vascular dementia and controls. The striking reduction of circulating sRAGE in Alzheimer disease further supports a role for the RAGE axis in this clinical entity and requires further investigation.     

Immunohistochemical localization of receptor for advanced glycation end (RAGE) products in the R6/2 mouse model of Huntington's disease

The receptor for advanced glycation end (RAGE) products is a multi-ligand receptor that belongs to the immunoglobulin superfamily of cell surface receptors, whose ligands are known to be upregulated in neuropathological conditions. RAGE upregulation has been described in neurodegenerative diseases, such as Alzheimer's disease, Creutzfeldt-Jakob's disease and Huntington's disease (HD). To analyze in detail the implication of RAGE in HD, we studied the immunohistochemical distribution of RAGE in the striatum of the R6/2 mouse model of HD, with particular attention to the neuronal subpopulations and their relative vulnerability to HD neurodegeneration. We show that RAGE immunoreactivity is evenly distributed to the cytoplasm of neurons in the wild type mouse, while it is finely granular in the cytoplasm of striatal neurons of R6/2 mouse. RAGE is distributed in 98% of spiny projection neurons, both in the normal mouse and in the R6/2. RAGE co-localizes with all of the striatal interneuron subsets both in the wild-type and in the R6/2 mouse. However, the intensity of RAGE immunoreactivity is significantly higher in the spiny neurons and in the PARV neurons of R6/2 mouse, whereas it is comparable between R6/2 and wild-type in the cholinergic and somatostatinergic interneurons. These data support the concept that RAGE is upregulated in the neurodegenerative process of HD, and suggests that its activation is related to the individual vulnerability of the striatal neuronal subtype.     

Soluble receptor for advanced glycation end products in multiple sclerosis: a potential marker of disease severity

OBJECTIVES: To compare serum levels of the receptor for advanced glycation end products (sRAGE) between multiple sclerosis (MS) patients and healthy control subjects, and to investigate whether serum sRAGE levels correlate with MS disease severity as indicated by the Kurtzke Expanded Disability Status Scale (EDSS). METHOD: 37 patients with clinical diagnosis of MS and 22 healthy control subjects were investigated in a cross-sectional study using enzyme-linked immunosorbent assays (ELISA). RESULTS: Serum levels of sRAGE were found to be significantly lower in MS patients compared to levels in healthy controls (p = 0.005). A trend toward lower levels of serum sRAGE was observed in female MS patients compared to their male counterparts (p = 0.05). A relationship between sRAGE and EDSS, and sRAGE and rate of clinical relapse was observed (p = 0.012). CONCLUSION: The significant reduction of sRAGE in MS patients relative to healthy controls supports the potential role for RAGE axis in MS clinical pathology. Lower levels of sRAGE may be associated with enhanced inflammatory responses. Based on these observations, further investigations into the role of sRAGE in MS clinical pathology is warranted.     

膝骨关节炎滑液中可溶性晚期糖基化终末产物受体水平与其病变程度的相关性

背景：研究表明骨关节炎患者关节滑液内可溶性晚期糖基化终末产物受体水平可能与关节炎病变的严重程度存在负相关,但在中国报道较少。 目的：观察膝关节骨关节炎患者关节滑液内可溶性晚期糖基化终末产物受体水平与其病变严重程度的关系。 方法：共纳入46名膝关节骨关节炎患者及14名健康对照者,纳入的骨关节炎患者符合美国风湿病学会骨关节炎的临床诊断标准。采用Kellgren-Lawrence的标准对膝关节骨关节炎病变严重程度进行分级,使用人可溶性晚期糖基化终末产物受体水平酶联免疫吸附试剂盒在酶标仪下检测测关节滑液的可溶性晚期糖基化终末产物受体水平。 结果与结论：膝关节骨关节炎患者关节滑液可溶性晚期糖基化终末产物受体水平较健康对照组显著降低(P < 0.01),且与膝关节骨关节炎病变严重程度呈显著独立负相关(r =-0.587,P < 0.01)。结果表明关节滑液可溶性晚期糖基化终末产物受体水平可能与膝关节骨关节炎病变的严重性和进展程度相关。     

Expression of the receptor for advanced glycation end products in oligodendrocytes in response to oxidative stress

Demyelination is a common result of oxidative stress in the nervous system, and we report here that the response of oligodendrocytes to oxidative stress involves the receptor for advanced glycation end products (RAGE). RAGE has not previously been reported in neonatal rat oligodendrocytes (NRO), but, by using primers specific for rat RAGE, we were able to show expression of messenger RNA (mRNA) for RAGE in NRO, and a 55-kDa protein was detected by Western blotting with antibodies to RAGE. Neonatal rat oligodendrocytes stained strongly for RAGE, suggesting membrane localization of RAGE. Addition of low concentrations of hydrogen peroxide (100 microM) initiated 55-kDa RAGE shedding from the cell membrane and the appearance of "soluble" 45-kDa RAGE in the culture medium, followed by restoration of RAGE expression to normal levels. Increasing hydrogen peroxide concentration (>200 microM) resulted in no restoration of RAGE, and the cells underwent apoptosis and necrosis. We further confirmed the observation in a human oligodendroglioma-derived (HOG) cell line. Both the antioxidant N-acetyl-L-cysteine and the broad-spectrum metalloproteases inhibitor TAPI0 were able partially to inhibit shedding of RAGE, suggesting involvement of metalloproteases in cleavage to produce soluble RAGE. The level of 55-kDa RAGE in autopsy brain of patients undergoing neurodegeneration with accompanying inflammation [multiple sclerosis and neuronal ceroid-lipofuscinosis (Batten's disease)] was much lower than that in age-matched controls, suggesting that shedding of RAGE might occur as reactive oxygen species accumulate in brain cells and be part of the process of neurodegeneration.     

晚期糖基化终产物受体与神经系统变性病关系的研究进展

晚期糖基化终产物受体(RAGE)作为细胞表面分子免疫球蛋白超家族多配体受体成员,在人体生理状态下呈低水平表达,当细胞处于激活或应激状态时,受损细胞中RAGE的表达增多.研究发现在多种与神经系统变性病有关的细胞上均发现了RAGE的过多表达,其与配体结合后激活细胞内各种信号转导机制,其中最重要的是氧化应激反应的增加和免疫炎性反应的加剧,最终产生致病效应.近年来的实验研究证明其与神经系统变性病的发生、发展的关系越来越紧密.通过本文的总结提示了抗RAGE抗体可能是治疗神经系统变性病的新靶点.     

Decreased plasma levels of soluble receptor for advanced glycation end products in mild cognitive impairment

Growing evidence advanced the idea that the soluble form of the receptor for advanced glycation end-products (sRAGE) might serve as a risk marker for several disorders including Alzheimer disease. We found a reduced level of circulating sRAGE in patients with mild cognitive impairment (MCI). The reduction of sRAGE in MCI, as well as the anticipation of the disease in patients with the lowest sRAGE levels (相似文献   

The role of receptor for advanced glycation end products (RAGE) in neuronal differentiation

The receptor for advanced glycation end products (RAGE) is a multiligand receptor protein thought to play an important role in neuronal differentiation. RAGE can bind a number of ligands and activate a variety of signalling pathways that lead to diverse downstream effects. Amphoterin and S100B are endogenous ligands, the interaction of which with RAGE is known to be involved in defined physiological processes. The present study investigated the spatiotemporal pattern of the expression for RAGE and its ligands, amphoterin and S100B, during neuronal differentiation of NT2/D1 cells. In this study, all three proteins were shown to increase with progression of neuronal differentiation as determined by Western blotting, raising the possibility that both amphoterin and S100B may interact with RAGE and have important functions during the process of cell differentiation. Moreover, blocking the activation of RAGE with neutralizing antibody in the presence of retinoic acid disrupted the progression of normal neuronal differentiation. Immunocytochemistry (ICC) studies showed that amphoterin partially colocalized with RAGE within differentiating NT2 cells, whereas S100B showed a high degree of colocalization. This result suggests that S100B is more likely to be the principal ligand for RAGE during the differentiation process and that RAGE and amphoterin might have both independent and combined roles. Moreover, RAGE was expressed only in cells that were committed to a neuronal phenotype, suggesting direct involvement of RAGE in mediating cellular changes within differentiating neuronal cells. Further detailed studies are now required to characterize fully the role of RAGE during the neuronal differentiation period.     

Advanced glycation end products co-localized with astrocytes and microglial cells in Alzheimer’s disease brain

   In the previous study [Takeda et al. (1996) Neurosci Lett 221: 17–21], we reported that the advanced glycation end products (AGEs) in the external space of neuronal perikarya (extraneuroperikaryal AGE deposits) were significantly abundant in the Alzheimer’s brain. In this study, we investigated the spatial relationship of the extraneuroperikaryal AGE (carbocymethyllysine and pentosidine) deposits in astrocytes and microglial cells in the Alzheimer’s disease brain using double immunolabelling for AGEs and astrocyte or microglial cell markers. Most of the extraneuroperikaryal AGE deposits were co-localized with glial fibrillary acidic protein-positive astrocytes. AGE deposit-bearing astrocytes also contained Gomori-positive granules. Furthermore, some of the extraneuroperikaryal AGE deposits were co-localized with microglial cells. These extraneuroperikaryal AGEs may activate astrocyte and microglia, and play a role in pathogenesis of Alzheimer’s disease. Received: 8 September 1997 / Revised: 19 November 1997 / Accepted: 12 February 1998     

Altered intracellular signaling and reduced viability of Alzheimer's disease neuronal cybrids is reproduced by beta-amyloid peptide acting through receptor for advanced glycation end products (RAGE)

Activation of apoptosis by increased production of amyloid beta peptides (Abeta) has been implicated in neuronal cell death of Alzheimer's disease (AD). We used mitochondrial transgenic cybrid models of sporadic AD (SAD), which overproduce Abeta compared to control (CTL) cybrids, to investigate the effects of endogenously generated Abeta on intracellular signaling pathways and viability. Reducing SAD Abeta production with gamma-secretase inhibition altered the total phosphorylation profile of SAD cybrid to one similar to CTL cybrids and enhanced viability to approximately CTL cybrid levels. Treating CTL cybrids with exogenous Abeta or conditioned media (CM) from SAD cybrids activated the signaling pathways active in SAD cybrids under basal condition and decreased viability. Antibodies against receptor for advanced glycation end products (RAGE) blocked Abeta-induced activation of the p38, JNK pathways, and NF-kappaB in CTL cybrids and offered protection against the neurotoxic effects of Abeta. Expression of SAD mitochondrial genes in cybrids activates stress-related signaling pathways and reduces viability. This SAD phenotype is produced by endogenously generated Abeta and can be replicated by exogenous Abeta acting through RAGE.     

晚期糖基化终产物受体在脑缺血损伤中的表达及作用机制

目的 通过研究RAGE在大鼠及人的缺血脑组织中的表达情况,结合体外神经细胞OGD模型中S100B、RAGE与TNF-α的相互作用结果,探讨RAGE在脑缺血损伤中的作用及相关机制.方法 采用免疫组织化学方法检测RAGE在不同缺血时间点实验大鼠和患者脑组织中的表达;建立体外神经细胞OGD模型,用ELISA方法检测TNF-α的表达.结果 （1）大鼠永久性MCAO 1h、6h、12h、24h、2d、6d缺血侧RAGE表达均明显高于非缺血侧（P＜0.01）,脑梗死患者＜2d组、3～5d组及＞5d组脑病理切片中缺血侧与非缺血侧对比RAGE表达均有显著性差异（P＜0.05）;（2）OGD培养的神经细胞,TNF-α表达量显著增加,与正常培养组相比P＜0.01;用S100B蛋白刺激神经细胞并OGD培养,可以引起神经细胞表达TNF-α的量增加S100B（P＜0.01）;阻断神经细胞表达RAGE后,TNF-α表达量也相应地下降（P＜0.01）.结论 RAGE参与脑缺血损伤过程,缺氧缺糖培养的神经细胞其损伤过程可以通过RAGE表达上调引起TNF-α表达来实现.