E3泛素连接酶CHIP与上皮性癌关系研究

泛素化修饰是机体一种非常重要的蛋白质翻译后修饰方式,其广泛参与细胞周期、DNA修复、信号转导、转录调控等生物学过程。近些年,蛋白质泛素化修饰在恶性肿瘤发生和发展中的作用,受到国内外广泛关注。尤其是E3泛素连接酶,它能特异性识别作用底物,泛素化修饰的特异性就取决于该连接酶。研究表明,E3泛素连接酶功能异常与恶性肿瘤等多种疾病的病理过程密切相关,因此分析特定的E3连接酶在恶性肿瘤中的作用和机制,有助于加深对恶性肿瘤发生、发展过程中分子机制的认识,为恶性肿瘤相关分子分类和治疗靶点提供实验基础。本文对E3泛素连接酶CHIP的功能,尤其与上皮性癌关系的研究进展进行综述。     

环境因素诱导的DNA甲基化修饰在唇腭裂发病中的作用研究进展

先天性唇腭裂（cleft lip with/without palate,CL/P）作为常见的颌面部发育畸形,其病因目前认为主要是遗传因素和环境因素共同作用的结果。研究发现,环境因素诱发的表观遗传学变化可能是胎儿先天畸形发生的关键因素,而DNA甲基化作为重要的表观遗传修饰之一,在众多领域已有广泛而深入的研究,但其作为联系个体与环境的纽带,在唇腭裂中的研究报道有限。现有研究表明,DNA甲基化与唇腭裂的发生密切相关,叶酸缺乏、吸烟、污染物暴露等不良环境因素的刺激可诱导DNA甲基化状态发生改变,从而影响唇腭发育的基因表达,导致畸形的发生。     

组蛋白修饰在口腔鳞状细胞癌中的研究进展

口腔鳞状细胞癌(oral squamous cell carcinoma, OSCC)是口腔颌面部最常见的恶性肿瘤,而OSCC患者就诊时往往疾病已发展到晚期阶段并出现肿瘤转移,导致预后不佳。OSCC的发病机制尚不清楚,目前早期有效监测OSCC发生、侵袭、转移及复发的分子靶点仍需要进一步探究。当前的研究显示,各种组蛋白修饰改变了染色质结构,进而影响相关下游基因的转录活性,调控基因表达水平,在OSCC的生物学检测、病理分级与分期、预后判断中均发挥重要作用。该文主要对组蛋白的甲基化、乙酰化、磷酸化、泛素化、二磷酸腺苷核糖基化等修饰在OSCC中的研究进展进行综述。     

精氨酸-甘氨酸-天冬氨酸修饰钛材料表面的研究进展

钛及其合金因良好的生物学性能被广泛应用于口腔医学领域,但钛金属是惰性材料,植入后不能直接和骨形成较好的结合,因此对钛及其合金表面进行生物改性一直是生物材料领域的研究热点.精氨酸-甘氨酸-天冬氨酸(RGD)作为钛材料表面修饰的候选蛋白质,广泛存在于纤连蛋白、玻连蛋白和骨涎腺蛋白等多种细胞外基质蛋白中,可调节细胞与血清及细胞外基质的附着,因此,本文就目前国内外对RGD修饰钛及其合金表面的主要研究进展作一综述.     

丝素蛋白抗菌性修饰在皮肤组织工程中的应用

丝素蛋白(silk fibroin,SF)是一种天然高分子纤维蛋白,常被用作理想敷料应用于口腔颌面部及全身皮肤创面的修复中.SF具有良好的生物相容性、可降解性和机械性能,可促进创面愈合,但其本身不具备抗菌性.通过不同的抗菌性修饰赋予SF材料抗菌性能已得到广泛的研究和关注.本文对SF抗菌性修饰材料在皮肤组织工程中的应用进...     

长链非编码RNA及其在自身免疫性疾病发生发展中的作用

长链非编码RNA(long non-coding RNA,lnc RNA)是一类长度超过200个核苷酸、不编码蛋白质的功能性RNA分子。lnc RNA通过表观遗传修饰与转录调控、转录后加工、翻译调控等多种机制,在细胞生命活动中发挥重要作用。最新研究表明,lnc RNA与免疫细胞的分化和激活密切相关,进而影响类风湿性关节炎、系统性红斑狼疮等多种自身免疫性疾病的发生发展,本文就lnc RNA在自身免疫性疾病中的研究进展进行综述。     

长链非编码RNA在牙周炎和口腔肿瘤疾病中的作用

长链非编码RNA(lncRNA)是一类内源性的长度大于200个核苷酸、缺少特异完整的开放阅读框,不具有或很少具有蛋白质编码功能的转录本,一度被认为是基因组转录中的噪音,没有生物学功能;而近来的研究显示,lncRNA可通过介导染色质重塑、组蛋白修饰、X染色体失活以及基因组印迹、转录、剪接、翻译、降解和转运等途径,在表观遗传水平、转录水平和转录后水平等层面上调控基因的表达,从而影响疾病的发生发展.在口腔疾病中,lncRNA与牙周炎、口腔癌前病变和口腔颌面部肿瘤等关系密切.超过60％的在癌组织中异常表达的lncRNA皆在口腔癌前病变组织中有异常表达,所以lncRNA不仅可以作为牙周炎、口腔癌前病变和口腔颌面部肿瘤诊断的潜在标志物,还可为临床预后的判断及治疗方案的确定提供指导.     

长链非编码RNA在骨发育中作用的研究进展

长链非编码RNA(Long non-coding RNAs,lncRNAs)是指长度大于200 nt、缺少开放阅读框(ORFs)的非编码RNA,其占非编码RNA的很大比例。长链非编码RNA在表观遗传、转录、翻译以及蛋白质修饰过程中发挥重要的调控作用,从而广泛地参与包括细胞分化、个体发育等在内的重要生命过程。同时越来越多的研究发现它也与人类某些重要疾病发生和发展密切相关。该文综述了lncRNAs在骨发育中的作用。     

比较蛋白质组学在口腔鳞癌中的研究进展

比较蛋白质组学是针对不同空间、不同时间上动态变化着的蛋白质组的整体比较,分析不同蛋白质组之间蛋白质在表达数量、表达水平和修饰状态上的差异,研究差异蛋白质及其功能.该文旨在从细胞、组织和体液方面,介绍比较蛋白质组学在口腔鳞癌中的研究进展.     

RNAi的作用机制及其在口腔医学领域的研究进展

RNA干扰是由双链RNA诱发的使特定序列基因沉默的现象,存在小干扰RNA(siRNA)和微小RNA(miRNA)两种不同的途径,主要有转录水平基因沉默,转录后水平基因沉默和翻译水平基因沉默三种机制,具有高效性和高特异性的特点。本文就RNAi的途径、技术路线及RNA干扰在牙齿发育、唇腭裂研究、牙周组织和口腔肿瘤中的研究进展作一综述。     

Structural and genetic aspects of proline-rich proteins

Considerable advances have been made in the genetics of salivary proline-rich proteins (PRP). The genes for acidic, basic, and glycosylated PRP have been cloned. They code for precursor proteins that all have an acidic N-terminal followed by proline-rich repeat sequences. Structural studies on secreted proteins have demonstrated that not only acidic but also some basic PRPs have this general structure. It is possible that mRNA for different PRP may have originated from a single gene by differential mRNA splicing, but post-translational cleavages of the primary translation product apparently also occur. In vitro translation of salivary gland mRNA results in a single precursor protein for acidic PRP. Such in vitro translated protein can be cleaved by salivary kallikrein, giving rise to two commonly secreted acidic PRPs, and kallikrein or kallikrein-like enzymes may be responsible for other post-translational cleavages of PRPs. Acidic as well as some basic PRPs are phosphorylated. A protein kinase has been demonstrated in salivary glands which phosphorylates the PRPs and other secreted salivary proteins in a cAMP and Ca2+-calmodulin-independent manner. Knowledge of the conformation of PRPs is limited. There is no conclusive evidence of polyproline-like structure in the proline-rich part of PRPs. Ca2+ binding studies on acidic PRPs indicate that there is interaction between the Ca2+ binding N-terminal end and the proline-rich C-terminal part. This interaction is relieved by modification of arginine side-chains. 1H, 32P, and 43Ca NMR studies have further elucidated the conformation of acidic PRPs in solution.(ABSTRACT TRUNCATED AT 250 WORDS)     

Establishment of porcine pulp-derived cell lines and expression of recombinant dentin sialoprotein and recombinant dentin matrix protein-1

The major non-collagenous proteins in dentin have extensive post-translational modifications (PTMs) that appear to be odontoblast-specific, so expression of recombinant dentin proteins in other cell types does not achieve the in vivo pattern of PTMs. We established cell lines from developing porcine dental papillae and used them to express recombinant dentin sialoprotein (DSP) and dentin matrix protein-1 (DMP1). Pulp cells were immortalized with pSV3-neo and clonally selected. Cell lines were characterized by reverse transcruption-polymerase chain reaction (RT-PCR) and assayed for alkaline phosphatase activity and mineralized nodule formation. One of the five cell lines (P4-2) exhibited an odontoblastic phenotype, as determined by expression of tooth-specific markers, response to cytokines, and ability to form mineralized nodules. DSP and DMP1 expression constructs were transiently transfected into various cell lines. DSP, expressed by P4-2 cells, contained chondroitin 6-sulfate, which is a defining modification of the DSP proteoglycan. DMP1 was secreted and cleaved by proteases, even in human kidney 293 cells, which normally do not express DMP1, demonstrating susceptibility to non-specific proteolysis. Both recombinant proteins enhanced P4-2 cell attachment in a dose-dependent manner. We conclude that we have immortalized porcine odontoblast-like cells which express recombinant dentin extracellular matrix components with post-translational modifications that closely resemble those produced in vivo.     

唾液蛋白质糖基化及其与全身和口腔疾病关系的研究进展

蛋白质糖基化是重要的蛋白质翻译后修饰方式之一,通过赋予蛋白质各种结构和功能特征而在生命活动中扮演重要角色。唾液作为一种获取简单且无创的生理物质,包含有来自血清、龈沟液、口咽黏膜分泌物的成分。近年来随着相关研究的深入,人们对唾液的认识被不断更新。研究发现,唾液蛋白质可以作为一些疾病的诊断指标,唾液中蛋白质糖基化修饰也与多种疾病状态密切相关。本文就唾液蛋白质糖基化及其与全身和口腔疾病关系的研究进展作一综述。     

Assembly and function of PG27/LptO,PG0026, and HagA in the secretion and modification system of C-terminal domain proteins

Background: The Gram-negative bacterium Porphyromonas gingivalis is considered as the etiologic agent of chronic periodontitis. P. gingivalis secretes C-terminal domain (CTD) proteins. CTD proteins pass through the outer membrane via the Por secretion system, undergo post-translational glycosylation by attaching deacylated anionic-lipopolysaccharide (A-LPS), and anchor the outer cell membrane and/or to the extracellular vesicles. These secretion and modification steps vary depending on the different CTD proteins but, in all cases, the CTDs of mature CTD proteins, except for the CTD signal peptidase, are removed. Since CTD proteins such as gingipains are known virulence factors of P. gingivalis, the mechanism of secretion and modification of CTD proteins needs to be elucidated.Highlight: Recent genetic studies have identified the genes essential for the secretion and modification of CTD proteins. Of particular interest is the functional role of each component; however, this issue is not easy to address. Recently, reports on PG0026 and PG27/LptO in the modification system have been published. PG0026 has been proposed as the CTD signal peptidase, while PG27 is an outer membrane protein consisting of a beta-barrel structure, and is bifunctional in the deacylation of A-LPS as LptO and in anchoring PG0026 and HagA to the cell surface.Conclusion: These findings describe the assembly and function of PG27/LptO, PG0026, and HagA.     

釉基质蛋白在牙髓细胞增殖中的作用

目的探讨釉基质蛋白对牙髓细胞增殖的作用及其机理。方法分离培养人的牙髓细胞,加入不同浓度的Emdogain,采用化学发光免疫测定方法比较牙髓细胞的生长情况,采用Superarray方法研究加入Emdogain对细胞周期相关因子的影响。结果牙髓细胞在不同浓度的Emdogain作用下呈现不同的生长速率。Emdogain促进牙髓细胞生长的最佳浓度为300μg/ml。细胞周期相关因子的Superarray分析显示,Emdogain通过上调cyclin D1,p21,E6-AP,SUMO-1基因达到对细胞生长的促进作用。结论适宜浓度的Emdogain（45～600μg/ml）能够促进牙髓细胞的增殖。     

Developmental-specific expression and immunoreactivity of keratins during odontogenesis in rat embryos

The enamel organ of the mammalian dental primordium undergoes a precise sequence of differentiation. To correlate this differentiation with tissue-specific markers we analysed the keratin protein composition and immunoreactivity of incisor primordia from the earliest stage of odontogenesis to the neonatal period. Throughout the enamel organ synthesized a characteristic subset of keratin proteins, and the expression of one specific keratin marked the onset of the cap stage. Interestingly, the immunoreactivity of the ameloblastic keratins against polyclonal antibodies increased with progressive odontogenesis, suggesting that cytokeratin filaments may undergo post-translational or conformational alterations during assembly within differentiating enamel-organ cells.     

The role of intracellular lysosomal enzymes in the autocellular-surveillance of unhydroxylated collagens in dermal and gingival fibroblasts

The turnover of unhydroxylated collagen was investigated in dermal and gingival fibroblasts derived from C57Bl/6J mice. Unhydroxylated collagen molecules were fostered by the inhibition of prolyl- and lysyl-hydroxylase by the addition of alpha, alpha' dipyridyl. Turnover of collagens was determined by single isotope continuous labeling, double-isotopic labeling, the use of lysosomal pH modulators, and proteinase inhibitors. These studies reveal that the turnover of unhydroxylated collagen is an extracellular event, in spite of the susceptibility of these abnormal structural and conformational proteins to proteolysis; the synthesizing cell does not utilize intracellular lysosomal enzymes as a means of modulating the quantities of non-helical unhydroxylated collagen as an intolerable post-translational error of protein processing.     

Multiple forms of statherin in human salivary secretions.

Sequential chromatography of hydroxyapatite-adsorbed salivary proteins from submandibular/sublingual secretions on Sephadex G-50 and reversed-phase HPLC resulted in the purification of statherin and several statherin variants. Amino acid analysis, Edman degradation and carboxypeptidase digestion of the obtained protein fractions led to the determination of the complete primary structures of statherin SV1, statherin SV2, and statherin SV3. SV1 is identical to statherin but lacks the carboxyl-terminal phenylalanine residue. SV2, lacking residues 6-15, is otherwise identical to statherin. SV3 is identical to SV2 but lacks the carboxyl-terminal phenylalanine. These results provide the first evidence for multiple forms of statherin which are probably derived both by post-translational modification and alternative splicing of the statherin gene.