角蛋白17与银屑病

角蛋白17作为一种细胞骨架蛋白,在银屑病患者皮损中过度表达,被认为是银屑病的一种特异性标志物。角蛋白17是一种自身抗原,携带某些和链球菌M6蛋白相似的表位。这些表位可以刺激自身反应性T细胞增殖,促进银屑病相关的细胞因子释放,继而进一步刺激角质形成细胞产生角蛋白17。研究表明角蛋白17/T细胞/细胞因子自身免疫环路可能参与银屑病的发病机制,角蛋白17有可能成为一种新的银屑病治疗靶点。     

角蛋白1和17在点滴状银屑病患者皮损中的表达

选用25例点滴状银屑病患者及8名正常人皮肤的石蜡切片,用免疫组化法检测K1、K17的表达,以探讨它们与银屑病的关系.结果显示,病例组和正常对照组K1的表达主要集中在基底层以上的棘层和颗粒层中,而在基底层几乎未见表达,病例组表达强度弱于对照组.正常对照组中K17在基底层、棘层和颗粒层中几乎未见表达.在病例组阳性细胞主要表达在离基底层2～3层上的各角质形成细胞中.K1和K17在点滴状银屑病皮损中均有异常表达,提示其与点滴状银屑病发病有一定关系.     

银屑病的治疗对相关角蛋白的影响

银屑病的确切病因目前仍不明,伴随表皮角质形成细胞的生长分化失调,其皮损中的角蛋白可有异常表达,现就银屑病与角蛋白的关系、国内外不同治疗方法对皮损中角蛋白的影响,及其与病情的关系做一综述.     

角蛋白,抗角蛋白自身抗体和银屑病

被作为上皮类型和分化阶段的分子标志－角蛋白，在银屑病患者表皮内明显地表现异常，并且这种异常改变不仅仅出现在皮损区域。最新研究提示屑病患者角朊细胞本身存在缺陷，它们较正常角朊细胞分化能力低下。直接以不同分子量的角蛋白作为对象的抗角蛋白自身抗体，也与银屑病有着明显的联系。有的角蛋白和抗角蛋白自身抗体可以作为判断银屑病的病情以及疗效、治愈标准的指标。深入研究银屑病患者角蛋白、抗角蛋白自身抗体的变化对进一     

角蛋白、抗角蛋白自身抗体和银屑病

被作为上皮类型和分化阶段的分子标志——角蛋白,在银屑病患者表皮内明显地表现异常并且这种异常改变不仅仅出现在皮损区域。最新研究提示银屑病患者角朊细胞本身存在缺陷,它们较正常角朊细胞分化能力低下。直接以不同分子量的角蛋白作为对象的抗角蛋白自身抗体,也与银屑病有着明显的联系。有的角蛋白和抗角蛋白自身抗体可以作为判断银屑病的病情以及疗效、治愈标准的指标。深入研究银屑病患者角蛋白、抗角蛋白自身抗体的变化对进一步了解银屑病可能提供一些有益的启迪。     

MiR-486-3p在银屑病皮损的表达及对角蛋白17表达的影响

目的 探讨银屑病患者皮损与健康人皮肤中miR-486-3p表达情况及其对角蛋白17（K17）表达的调控作用。 方法　采用生物信息学方法预测出调节K17表达的微RNA（microRNA）,选取10例银屑病患者皮损和10例健康人皮肤提取RNA,用加PolyA尾法逆转录为cDNA,实时荧光定量PCR（qRT-PCR）进行荧光定量。用miR-486-3p模拟物（mimics）和阴性对照物（NC）转染人永生化角质形成细胞（HaCaT细胞）,Western印迹检测K17表达情况;构建双荧光素酶报告系统,其中包括含有K173′UTR的片段,突变1组为将种子序列删除的片段,突变2组为将种子序列间隔突变的片段,突变3组为将种子序列重复2次的片段,并检测miR-486-3p是否与K17 3′UTR种子序列结合而抑制K17表达。 结果　银屑病皮损中miR-486-3P表达水平为0.211 ± 0.120,低于健康对照的0.555 ± 0.425,银屑病皮损为健康对照的0.380,两组比较,t = 2.62,υ = 9,P < 0.05。Western印迹结果显示,miR-486-3p类似物转染HaCaT细胞后,K17表达水平明显降低。双荧光素酶报告系统检测结果,含有K173′UTR种子序列组与突变3组荧光强度分别为65.31 ± 6.32和54.18 ± 10.01,均低于对照组（P < 0.05）;突变1组和突变2组荧光强度分别为114.77 ± 16.14和110.21 ± 12.99,与对照组差异无统计学意义（P > 0.05）。 结论 miR-486-3p 在银屑病皮损中的表达水平低于健康人皮肤,miR-486-3p通过与K17 3′UTR种子序列结合抑制K17表达,提示其表达水平降低及对K17调控作用的改变可能与银屑病的发生与发展相关。     

角蛋白17对银屑病患者T细胞增殖和分泌干扰素γ的影响

目的 检测人角蛋白17对银屑病患者T细胞增殖和细胞因子分泌的影响。方法 从银屑病皮损中提取总RNA,反转录成cDNA,通过PCR方法扩增人角蛋白17基因,利用GST融合表达载体pGEX-4T-1表达相应融合蛋白;梯度离心和绵羊红细胞花环沉淀法分离纯化T细胞;直接活细胞计数和MTT法检测T细胞增殖程度,ELISA检测培养上清液中干扰素γ浓度。结果 和正常人对照相比,角蛋白17可以显著促进银屑病患者T细胞的增殖,并且促进其分泌干扰素γ(P值均<0.001)。结论 角蛋白17对银屑病患者T细胞功能的促进作用提示其可能是引发银屑病的重要自身抗原之一。     

Th17细胞与银屑病

Th17细胞是近年来发现的一种新型的CD4＋T辅助细胞,它不同于经典的Th1和Th2细胞,有其独立的分化途径,表达控制其分化的独特转录因子——孤独受体。它通过分泌IL-17、IL-22等细胞因子发挥作用,现已证实其在防御胞外菌感染、介导慢性炎症、自身免疫病和肿瘤发病中发挥重要作用。本文就Th17细胞与银屑病的关系作一综述,期望可以对银屑病的发病机制有更进一步的认识。     

白介素-17家族与银屑病

白介素-17(interleukin-17,IL-17)家族成员包括六个配体(IL-17A至IL-17F)以及五个受体(IL-17RA至IL-17RE)。各个配体通过与相应的受体复合体结合而发挥生物学效应。IL-17通过刺激抗微生物肽、趋化因子及促炎性细胞因子的释放防御外界病原体的侵袭。同时也因为IL-17诱导了一些促炎性细胞因子、趋化因子等表达增加,而被证实其与多种炎症性及自身免疫性疾病的发病相关。本文重点探讨IL-17家族各成员与银屑病发病的相关性。     

银屑病患者抗角蛋白自身抗体的初步研究

银屑病患者表皮中角蛋白有异常表达,特别是角蛋白K16,它常在银屑病活动的早期即在皮损边缘处的基底层上表达^[1,2]。为了研究银屑病患者血清中是否存在针对角蛋白K16的自身抗体,以及该抗体与银屑病病情变化的确切关系,我们用间接酶联免疫测定法(ELISA)和免疫印迹法(IBT)分别检测银屑病患者血清中的抗角蛋白自身抗体(AKautoAB)和抗角蛋白K16自身抗体(AK16autoAB)的滴度。     

多发性脂囊瘤角蛋白17基因的突变研究

目的:研究多发性脂囊瘤(SM)角蛋白17基因的突变,为进一步开展基因诊断和基因治疗奠定基础。方法:抽取多发性脂囊瘤患者、患者父母以及100例正常人静脉血提取基因组DNA,采用聚合酶链反应(PCR)的方法对角蛋白17外显子1及其侧翼和外显子6进行扩增,并对其PCR产物直接进行双向测序以检测突变。结果:在家系中两例患者第42位密码子由CTG突变为CCG,结果导致角蛋白17 V1区杂合错义突变(L42P),即亮氨酸由脯氨酸替代,而此家系中的正常人和与该家系无关的100例正常人的DNA测序结果未发现此突变。结论:此家系中患者表型可能由角蛋白17基因头区的L42P突变所致。     

Keratin: A Journey of Three Decades

During the past three decades, major progress has been made in our understanding of the processes which lead to the formation of a keratinized epidermis in normal and pathologic situations. Stimulated by clinical studies of exfoliative dermatitis and related diseases, a series of investigations have been performed which proved initially that the pathways and controls of epidermal protein synthesis were equivalent to protein synthetic pathways in all other tissues of the body. Keratin was identified as not only an insoluble protein which makes up the vast majority of the intracellular protein in the stratum corneum, but as a member of the intermediate filament family of cytoskeletal proteins. Of all such proteins, the keratins are most complex, occurring in two families separable on the basis of size, structure and isoelectric point. The keratin intermediate filaments are heteropolymers of two paired components, one from each family. The pairs of keratins which form the intermediate filaments in basal and differentiated layers of epidermis and other epithelia have been defined and antibodies to specific keratins are now being used for diagnostic purposes. Sophisticated biochemical, physicochemical, and molecular biologic studies have led to complete definitions of almost all the epithelial keratin molecules and to cloning of their genes. These genes are currently being used in analyses of control of keratin expression and definition of the specific abnormalities associated with “keratinopathies” including epidermolysis bullosa simplex and epidermolytic hyperkeratosis.     

Keratin 17 as a therapeutic target for the treatment of psoriasis

Keratin 17 (K17) is the only ectopically expressed keratin in psoriatic lesional epidermis. This review focuses mainly on reports that have addressed the mechanism of K17 up-regulation and its biological role in psoriasis. In addition to IFN-γ, IL-17A and IL-22, which are derived from Th17 and Th22 cells, could up-regulate K17 mRNA and protein levels in keratinocytes in a dose-dependent manner. Moreover, these effects are partially blocked with STAT1- and STAT3-specific inhibitors, as well as small interfering RNA (siRNA) targeting STAT1 and STAT3. On the other hand, the HLA DRB1*04 and/or *07 positive patients show significant T cell responses to two peptides from K17 protein selected on the basis of predicted HLA DRB1*04 and/or *07 bindings. One peptide contains the ALEEAN sequence, while the other peptide has an amino acid sequence that has not been previously reported. Analysis of these processes led us to propose the existence of a K17/T cells/cytokine autoimmune loop, in which ectopically expressed K17 impacts on the maintenance of psoriasis by activating autoreactive T cells. Furthermore, it has been found that altered peptide ligands, which are produced through single alanine residue substitutions at a critical TCR contact position, abolish the T cell proliferation and IFN-γ production induced by K17 pathogenic peptides. K17-specific antisense ODNs and RNAi suppress K17 mRNA and protein expression in psoriatic skin in vivo, which coincides with marked clinical and histological improvement. These findings highlight K17 as an attractive target for novel therapies aimed at curtailing psoriasis driven by chronic inflammation.     

角蛋白17的置换肽的克隆表达及纯化

目的克隆角蛋白17的置换肽(APL),表达并纯化置换肽。方法将人工合成的置换肽DNA片段连接至表达载体pGEX4T1,转化大肠杆菌,IPTG诱导表达融合蛋白,分析鉴定表达蛋白,并纯化蛋白。结果①连接到载体的DNA序列,序列测定证实与已知序列一致;②成功构建了融合表达载体;③表达了pGEX4TS12E融合蛋白;④得到纯化的融合蛋白。结论人角蛋白17的置换肽的克隆成功及融合蛋白的表达与纯化,为进一步探索置换肽的功能打下了基础。     

Keratin 17 mutations cause either steatocystoma multiplex or pachyonychia congenita type 2

Pachyonychia congenita type 2 (PC-2; Jackson–Lawler syndrome) is an autosomal dominant disorder characterized by hypertrophic nail dystrophy, mild focal keratoderma, multiple pilosebaceous cysts and other features of ectodermal dysplasia. Keratin 17 (K17) is a differentiation-specific keratin expressed in the nail bed, hair follicle, sebaceous gland and other epidermal appendages. Previously, we have demonstrated that PC-2 is caused by mutations in K17 and that similar mutations in this gene can present as steatocystoma multiplex with little or no nail dystrophy. Here, we describe three unrelated kindreds carrying K17 mutations. Two of these families have identical missense mutations (R94C) in the 1A domain of K17. However, while affected members of one kindred have the classical features of PC-2, affected persons in the other family have the steatocystoma multiplex phenotype. In a third family with PC-2, mutation N92S was detected, bringing the total number of distinct mutations reported in K17 thus far to 11. These results demonstrate that K17 mutations commonly underlie both PC-2 and steatocystoma multiplex and that the alternate phenotypes which arise from these genetic lesions in K17 are independent of the specific mutation involved.