糖基化终产物与糖尿病血管并发症关系的研究进展

糖尿病是临床上一种常见病和多发病 ,血管并发症是糖尿病的主要致残及致死原因。流行病学调查资料表明 ,糖尿病患者发生动脉粥样硬化及危及生命的心血管并发症的危险性较常人增加 3- 4倍 ,而高血糖状态下蛋白质发生的非酶糖基化对糖尿病血管并发症起了重要作用。大量的资料已证明 ,糖尿病患者体内存在着一种重要的毒性产物———糖基化终产物 (ａｄｖａｎｃｅｄｇｌｙｃｏｓｙｌａｔｉｏｎｅｎｄｐｒｏｄ ｕｃｔｓ,ＡＧＥｓ)。本文对有关ＡＧＥｓ在糖尿病血管病变中致病作用的研究进展综述如下 :一、ＡＧＥｓ的生物化学特性及结构早在 1 91 …     

酶制剂Ceredase替代治疗高雪氏病—附一例分析

酶制剂Ｃｅｒｅｄａｓｅ替代治疗高雪氏病──附一例分析石慧文，臧晏，胡亚美，施惠平高雪氏病（Ｇａｕｃｋｅｒ＇ｓｄｉｓｅａｓｅ，ＧＤ）是一种常染色体隐性边传的代谢性疾病，是由于溶酶体β－葡萄糖脑苷脂酶β（ｇｌｕｃｏｃｅｒｅｂｒｏｓｌｕａｓｅ）缺陷所引起的...     

糖基化终产物增加人外周血单核细胞对单核 细胞趋化蛋白-1的表达

动脉粥样硬化 (Ａｔｈｅｒｏｓｃｌｅｒｏｓｉｓ ,ＡＳ)是严重危害人类健康的疾病 ,糖尿病患者并发ＡＳ的可能性是正常人的 3～ 4倍。高血糖状态下蛋白质发生的非酶糖基化可使其最终形成不可逆的糖基化终产物 (Ａｄｖａｎｃｅｄｇｌｙｃｏｓｙｌａｔｉｏｎｅｎｄｐｒｏｄｕｃｔｓ,ＡＧＥｓ)。ＡＧＥｓ可与单核细胞等多种细胞上受体结合 ,加速动脉粥样斑块的形成。单核细胞粘附于内皮并透入内皮下形成泡沫细胞是ＡＳ的早期事件。这一过程与单核细胞趋化蛋白- 1 (Ｍｏｎｏｃｙｔｅｃｈｅｍｏａｔｔｒａｃｔａｎｔｐｒｏｔｅｉｎ - 1 ,ＭＣＰ -…     

糖基化终产物促进培养的人脐静脉内皮细胞表达单核细胞趋化蛋白-1

目的 :糖尿病血管并发症如动脉粥样硬化 (Ａｔｈｅｒｏｓｃｌｅｒｏｓｉｓ,ＡＳ)等是糖尿病主要的致死致残原因。高血糖状态下非酶糖基化可使蛋白质最终形成不可逆的糖基化终产物 (ａｄｖａｎｃｅｄｇｌｙｃｏｓｙｌａｔｉｏｎｅｎｄｐｒｏｄｕｃｔｓ,ＡＧＥｓ)。糖尿病患者体内ＡＧＥｓ水平较正常人明显增高。动脉粥样斑块和泡沫细胞中均存在大量的ＡＧＥｓ,ＡＧＥｓ可与内皮细胞等多种细胞上受体结合 ,发挥生物学效应 ,加速粥样斑块的形成。单核细胞趋化蛋白 - 1 (ｍｏｎｏｃｙｔｅｃｈｅｍｏａｔｔｒａｃｔａｎｔｐｒｏｔｅｉｎ - 1 ,Ｍ…     

破骨细胞分化成熟调节的分子机理研究进展

破骨细胞 (ｏｓｔｅｏｃｌａｓｔ ,ＯＣ)来源于骨髓中的粒 -巨噬细胞克隆形成单位 (ｇｒａｎｕｌｏｃｙｔｅａｎｄｍａｃｒｏｐｈａｇｅｃｏｌｏｎｙｆｏｒｍｉｎｇｃｅｌｌｓ ,ＣＦＵ -ＧＭ)。ＯＣ的分化和 /或功能变化所导致的骨再建失衡是多种代谢性骨病 ,如骨质疏松症、骨质硬化症和畸形性骨炎 (Ｐａｇｅｔ骨病 )等形成的病理基础。目前已经证明多种激素和局部细胞因子如活性维生素Ｄ3 (1,2 5 (ＯＨ) 2 Ｄ3 )、糖皮质激素、甲状旁腺素 (ＰＴＨ)、前列腺素 (ＰＧＥ2 )、ＩＬ - 4、ＩＬ -6、ＩＬ - 11、ＩＬ - 12等不仅能调节破骨细胞生成…     

糖皮质激素对PMA诱导的CD18表达的抑制作用及机制

国内外大量研究表明糖皮质激素 (ｇｌｕｃｏｃｏｒｔｉｃｏｉｄ ,ＧＣ)能明显抑制包括由于ＣＤ1 8在内的多种粘附分子的表达。以往研究多限于ＣＤ1 8蛋白质水平 ,无法阐明ＧＣ -ＧＲ使细胞表面ＣＤ1 8数量减少 ,是由于合成减少 ,分解增多 ,还是细胞内转位过程受到抑制 (ＣＤ1 8从胞内储存池脱落并转位至质膜有关 )。对ＧＣ在ＣＤ1 8基因转录水平上的抑制作用极其机制目前研究得很少。目的 :探讨ＧＣ抑制ＣＤ1 8ｍＲＮＡ表达的作用及机制。方法 :本研究以细胞激活剂ＰＭＡ诱导下的人组织淋巴瘤细胞系Ｕ937细胞和人早幼粒白血病细胞系ＨＬ - 6…     

含ITIM的新型膜蛋白分子LLIR及其跨膜缺失突变体的克隆与功能研究

树突状细胞 (ｄｅｎｄｒｉｔｉｃｃｅｌｌｓ ,ＤＣｓ)是重要的抗原提呈细胞 ,其部分功能需要通过膜受体来介导 ,研究ＤＣｓ表面的受体是了解抗原提呈功能机制的途径之一。研究得较早的与ＤＣｓ功能相关的膜表面分子有ＤＥＣ - 2 0 5和ＭＭＲ ,这两个分子都是Ⅰ型跨膜蛋白 ,胞外含有数个Ｃ型ｌｅｃｔｉｎ结构域 ,对于ＤＣｓ摄取抗原的功能很重要。另外 ,也有带ｌｅｃｔｉｎ结构域的Ⅱ型跨膜分子被发现 ,如ＣＬＥＣ - 1、ＣＬＥＣ - 2、Ｄｅｃｔｉｎ - 1、Ｄｅｃｔｉｎ - 2 ,这些分子的胞外段都含有一个ＣＲＤ ,除了在ＤＣｓ表达以外 ,也在髓…     

温筋通对糖尿病大鼠心血管组织糖基化终产物的形成 及其受体和ICAM-1表达的影响

目的 :糖尿病血管并发症包括动脉粥样硬化和微循环功能障碍 ,是糖尿病患者致残和死亡的主要原因。虽然糖尿病血管损伤产生的机制尚未完全阐明 ,但最近研究表明糖基化终产物 (ａｄｖａｎｃｅｄｇｌｙｃａｔｉｏｎｅｎｄ -ｐｒｏｄｕｃｔｓ,ＡＧＥｓ)在组织内的沉积是血管病变的主要特征。这些ＡＧＥｓ沉积于血管壁或组织内与ＡＧＥｓ受体 (ｒｅｃｅｐｔｏｒｆｏｒＡＧＥｓ ,ＲＡＧＥ)相互作用 ,使细胞内信号传导改变 ,激活核转录因子引起靶基因的一系列反应 ,是导致糖尿病血管并发症的关键途径。为了寻求临床上抑制ＡＧＥｓ形成的药物 ,本实…     

单核细胞趋化蛋白-1在糖尿病肾病中的研究进展

糖尿病肾病（ｄｉａｂｅｔｅｉｃｎｅｐｈｒｏｐａｔｈｙ，ＤＮ）的发病机制十分复杂 ,已基本确认的病因有 :高糖 -蛋白激酶Ｃ(ＰＫＣ）途径 ,蛋白质的非酶糖化 -晚期糖化终产物（ａｄ＿ｖａｎｃｅｄｇｌｙｃａｔｉｏｎｅｎｄｐｒｏｄｕｃｔｓ，ＡＧＥｓ）途径 ,醛糖还原酶（ＡＲ） -多元醇途径 ,氧化应激（ｏｘｉｄａｔｉｖｅｓｔｒｅｓｓ）途径 ［１，２］,以及局部肾素血管紧张素系统（ｒｅｎｎｉｎａｎｇｉｏｔｅｎｓｉｎｓｙｓ ｔｅｍ，ＲＡＳ）等。单核细胞趋化蛋白 -１（ｍｏｎｏｃｙｔｅｃｈｅｍｏａ＿ｔｒａｃｔｔａｎｔｐｒｏｔｅ…     

心血管组织糖基化终产物的形成与其受体表达的关系

晚期糖基化终产物 (ａｄｖａｎｃｅｄｇｌｙｃａｔｉｏｎｅｎｄｐｒｏｄｕｃｔｓ ,ＡＧＥｓ)的形成是糖尿病血管并发症病理变化的一个特征。ＡＧＥｓ与其受体 (ｒｅｃｅｐｔｏｒｆｏｒＡＧＥｓ,ＲＡＧＥ)结合引起细胞内信号转导的变化 ,激活核转录因子引起靶基因的一系列反应 ,是导致糖尿病血管并发症的关键途径。目的 :本实验探讨了ＡＧＥｓ在糖尿病大鼠心血管组织内的形成量与ＲＡＧＥ基因表达的关系。方法 :雄性Ｗｉｓｔａｒ大鼠分为 :1 :对照组 ( 8只 ) ;2 :糖尿病 4周组 ( 6只 ) ;3:糖尿病 1 2周组 ( 8只 ) ;4:糖尿病 4周氨基胍 (ＡＧ)…     

Immune dysfunction in MGAT2‐CDG: A clinical report and review of the literature

Glycosylation is a critical post/peri‐translational modification required for the appropriate development and function of the immune system. As an example, abnormalities in glycosylation can cause antibody deficiency and reduced lymphocyte signaling, although the phenotype can be complex given the diverse roles of glycosylation. Human MGAT2 encodes N‐acetylglucosaminyltransferase II, which is a critical enzyme in the processing of oligomannose to complex N‐glycans. Complex N‐glycans are essential for immune system functionality, but only one individual with MGAT2‐CDG has been described to have an abnormal immunologic evaluation. MGAT2‐CDG (CDG‐IIa) is a congenital disorder of glycosylation (CDG) associated with profound global developmental disability, hypotonia, early onset epilepsy, and other multisystem manifestations. Here, we report a 4‐year old female with MGAT2‐CDG due to a novel homozygous pathogenic variant in MGAT2, a 4‐base pair deletion, c.1006_1009delGACA. In addition to clinical features previously described in MGAT2‐CDG, she experienced episodic asystole, persistent hypogammaglobulinemia, and defective ex vivo mitogen and antigen proliferative responses, but intact specific vaccine antibody titers. Her infection history has been mild despite the testing abnormalities. We compare this patient to the 15 previously reported patients in the literature, thus expanding both the genotypic and phenotypic spectrum for MGAT2‐CDG.     

DPAGT1-CDG: report of a patient with fetal hypokinesia phenotype

Congenital disorders of glycosylation (CDG) are due to either defects in the synthesis of the glycan moiety of glycoproteins or glycolipids and in the attachment of the glycans to proteins and lipids. Some 50 CDG have been identified. They represent a challenge for clinicians because most are multisystem diseases with a heterogeneous spectrum of clinical manifestations with involvement of any organ and system. We report on a patient with a mutation in the glycosyltransferase encoded by the DPAGT1 gene, an infrequent CDG. He showed severe fetal hypokinesia phenotype with decreased fetal movements and polyhydramnios. At birth he showed decreased facial expression, without nasolabial folds, soft long ears, U-shaped vermilion of the upper lip, thick skin, hypertrichosis, camptodactyly, moderate multiple contractures, hypotonia and severe hypokinesia, no spontaneous movements, and very limited movements with stimuli; he died at 1? months. Isoelectrofocusing of serum transferrin showed a type 1 pattern with increased asialo- and disialotransferrin. The study of the DPAGT1 gene showed he was a compound heterozygote for two novel point missense mutations [c.901C>T]+[c.1094T>G]. This phenotype expands the clinical features of the few DPATG1-CDG patients reported.     

Mutations in TRAPPC11 are associated with a congenital disorder of glycosylation

Congenital disorders of glycosylation (CDG) are a heterogeneous and rapidly growing group of diseases caused by abnormal glycosylation of proteins and/or lipids. Mutations in genes involved in the homeostasis of the endoplasmic reticulum (ER), the Golgi apparatus (GA), and the vesicular trafficking from the ER to the ER–Golgi intermediate compartment (ERGIC) have been found to be associated with CDG. Here, we report a patient with defects in both N‐ and O‐glycosylation combined with a delayed vesicular transport in the GA due to mutations in TRAPPC11, a subunit of the TRAPPIII complex. TRAPPIII is implicated in the anterograde transport from the ER to the ERGIC as well as in the vesicle export from the GA. This report expands the spectrum of genetic alterations associated with CDG, providing new insights for the diagnosis and the understanding of the physiopathological mechanisms underlying glycosylation disorders.     

Therapeutic approaches in Congenital Disorders of Glycosylation (CDG) involving N-linked glycosylation: an update

Congenital disorders of glycosylation (CDG) are a group of clinically and genetically heterogeneous metabolic disorders. Over 150 CDG types have been described. Most CDG types are ultrarare disorders. CDG types affecting N-glycosylation are the most common type of CDG with emerging therapeutic possibilities. This review is an update on the available therapies for disorders affecting the N-linked glycosylation pathway. In the first part of the review, we highlight the clinical presentation, general principles of management, and disease-specific therapies for N-linked glycosylation CDG types, organized by organ system. The second part of the review focuses on the therapeutic strategies currently available and under development. We summarize the successful (pre-) clinical application of nutritional therapies, transplantation, activated sugars, gene therapy, and pharmacological chaperones and outline the anticipated expansion of the therapeutic possibilities in CDG. We aim to provide a comprehensive update on the treatable aspects of CDG types involving N-linked glycosylation, with particular emphasis on disease-specific treatment options for the involved organ systems; call for natural history studies; and present current and future therapeutic strategies for CDG.     

The challenge of CDG diagnosis

Congenital disorders of glycosylation (CDG) are a rapidly growing family of genetic diseases that currently includes some 130 different types. CDG diagnosis is a challenge, not only because of this large number but also because of the huge clinical heterogeneity even within a number of CDG. In addition, the classical screening test, serum transferrin isoelectrofocusing, is only positive in about 60% of CDG, and can even become negative in some CDG particularly in PMM2-CDG, the most frequent N-glycosylation defect. In order to facilitate CDG diagnosis, we hereby provide some practical tools: (1) a list of clinical features strongly suggestive of a distinctive CDG; (2) a table of clinical, biochemical and laboratory findings reported in CDG, arranged per organ/system; (3) an overview of the affected organs/systems in each CDG; and (4) a diagnostic decision tree in face of a patient with a suspicion of CDG. Most important is to keep in mind a CDG in any unexplained syndrome, in particular when there is neurological involvement.This mini-review enumerates clinical and biochemical hallmarks of these diseases and the biochemical and genetic testing available, and provides an updated list and information on identified CDG. The main aim is to act as a CDG diagnosis simplified guide for healthcare professionals and, additionally, as an awareness and lobbying tool to help in the effectiveness and promptness of CDG diagnosis.     

Deficiency of the first mannosylation step in the N-glycosylation pathway causes congenital disorder of glycosylation type Ik

Defects of N-linked glycosylation represent diseases with multiple organ involvements that are classified as congenital disorders of glycosylation (CDG). In recent years, several CDG types have been attributed to defects of dolichol-linked oligosaccharide assembly in the endoplasmic reticulum. The profiling of [3H]mannose-labeled lipid-linked oligosaccharides was instrumental in identifying most of these glycosylation disorders. However, this method is poorly suited for the identification of short lipid-linked oligosaccharide biosynthesis defects. To adequately resolve deficiencies affecting the first steps of lipid-linked oligosaccharide formation, we have used a non-radioactive procedure employing the fluorescence detection of 2-aminobenzamide-coupled oligosaccharides after HPLC separation. By applying this method, we have detected the accumulation of dolichylpyrophosphate-GlcNAc2 in a previously untyped CDG patient. The accumulation pattern suggested a deficiency of the ALG1 beta1,4 mannosyltransferase, which adds the first mannose residue to lipid-linked oligosaccharides. This was supported by the finding that this CDG patient was compound heterozygous for three mutations in the ALG1 gene, leading to the amino acid substitutions S150R and D429E on one allele and S258L on the other. The detrimental effect of these mutations on ALG1 protein function was demonstrated in a complementation assay using alg1 Saccharomyces cerevisiae yeast mutants. The ALG1 mannosyltransferase defect described here represents a novel type of CDG, which should be referred to as CDG-Ik.     

Oligosaccharyltransferase complex‐congenital disorders of glycosylation: A novel congenital disorder of glycosylation

Congenital disorders of glycosylation (CDG) are metabolic disorders that affect the glycosylation of proteins and lipids. Since glycosylation affects all organs, CDG show a wide spectrum of phenotypes. We present a patient with microcephaly, dysmorphic facies, congenital heart defect, focal epilepsy, infantile spasms, skeletal dysplasia, and a type 1 serum transferrin isoelectrofocusing due to a novel CDG caused by a homozygous variant in the oligosaccharyltransferase complex noncatalytic subunit (OSTC) gene involved in glycosylation and confirmed by serum transferrin electrophoresis.     

Antisense‐mediated therapeutic pseudoexon skipping in TMEM165‐CDG

Deficiencies in glycosyltransferases, glycosidases or nucleotide‐sugar transporters involved in protein glycosylation lead to congenital disorders of glycosylation (CDG), a group of genetic diseases mostly showing multisystem phenotype. Despite recent advances in the biochemical and molecular knowledge of these diseases, no effective therapy exists for most. Efforts are now being directed toward therapies based on identifying new targets, which would allow to treat specific patients in a personalized way. This work presents proof‐of concept for the antisense RNA rescue of the Golgi‐resident protein TMEM165, a gene involved in a new type of CDG with a characteristic skeletal phenotype. Using a functional in vitro splicing assay based on minigenes, it was found that the deep intronic change c.792+182G>A is responsible for the insertion of an aberrant exon, corresponding to an intronic sequence. Antisense morpholino oligonucleotide therapy targeted toward TMEM165 mRNA recovered normal protein levels in the Golgi apparatus of patient‐derived fibroblasts. This work expands the application of antisense oligonucleotide‐mediated pseudoexon skipping to the treatment of a Golgi‐resident protein, and opens up a promising treatment option for this specific TMEM165‐CDG.     

Epilepsy and movement disorders in CDG: Report on the oldest‐known MOGS‐CDG patient

Congenital glycosylation disorders (CDG) are inherited metabolic diseases due to defective glycoprotein and glycolipid glycan assembly and attachment. MOGS‐CDG is a rare disorder with seven patients from five families reported worldwide. We report on a 19‐year‐old girl with MOGS‐CDG. At birth she presented facial dysmorphism, marked hypotonia, and drug‐resistant tonic seizures. In the following months, her motility was strongly limited by dystonia, with forced posture of the head and of both hands. She showed a peculiar hyperkinetic movement disorder with a rhythmic and repetitive pattern repeatedly documented on EEG‐polygraphy recordings. Brain MRI showed progressive cortical and subcortical atrophy. Epileptic spasms appeared in first months and ceased by the age of 7 years, while tonic seizures were still present at last assessment (19 years). We report the oldest‐known MOGS‐CDG patient and broaden the neurological phenotype of this CDG.     

Molecular diagnosis of congenital disorders of glycosylation

Congenital disorders of glycosylation are a group of inherited disorders, characterized by a central nervous system dysfunction and multiorgan failure associated with defective N-glycosylation. CDG-I comprises all defects in the assembly of the dolichol-linked glycan and its transfer to the protein, whereas CDG-II refers to defects in the processing of the protein-bound glycans. The diagnosis is done by the presence of hypoglycosylated glycoproteins in the serum and typing by enzymatic assay (available for CDG-Ia and Ib) and/or mutation detection. We give an overview of the latest results of molecular diagnosis from the French CDG I families. We report novel mutations and their functional study. In addition we looked for a founder effect for the most frequent mutations observed in the French population.