丝聚合蛋白基因突变及其相关皮肤病的研究进展

丝聚合蛋白又称为微丝凝聚蛋白,是一种广泛存在于皮肤表皮的碱性蛋白质。主要功能是与角蛋白中间丝相互作用,协同角蛋白的聚集,从而起到维护皮肤的屏障的功能。近几年来,随着对丝聚合蛋白基因(FLG)的研究的不断深入,越来越多的证据显示,该基因的突变与多种皮肤疾病的发生相关。明确FLG基因与其相关疾病的关系,不仅能够加深对该疾病的认识,而且还可以从基因水平改变FLG基因的表达来改善皮肤的屏障功能。本文主要对FLG基因突变所引起的皮肤相关疾病进行综述。     

特应性皮炎与丝聚蛋白研究进展

丝聚蛋白(FLG)基因的失功能突变可使表皮FLG含量减少或缺失,进而引起表皮屏障功能发生改变,增加特应性皮炎(AD)的患病风险。本文对FLG在表皮屏障形成中的作用、FLG基因结构、FLG基因在AD患者中的突变情况及FLG基因突变与AD临床表型的相关性进行综述。     

FLG基因SNPs与延边朝鲜族特应性皮炎的相关性

目的探讨丝聚蛋白(FLG)基因单核苷酸多态性(SNPs)与延边地区朝鲜族特应性皮炎(AD)的关系。方法选择70例AD患者和90例正常对照人群作为研究对象,使用PCR法,分析FLG基因2个SNPs位点(rs11584340及rs3126085)的基因型与等位基因情况,探讨AD组及对照组等位基因、基因型频率分布情况。结果 FLG基因2个SNPs rs11584340(G)和rs3126085(G)等位基因频率、基因型频率在AD组、对照组之间均符合Hardy-Weinberg平衡定律(P0.05);在延边朝鲜族人群AD组与对照组之间rs11584340和rs3126085位点的等位基因频率、基因型频率差异无统计学意义(P0.05);rs11584340与rs3126085为强连锁不平衡(D'=1.00,r~2=0.84);延边地区朝鲜族FLG基因2个SNPs的等位基因频率与Hap Map数据库(ss41111533,ss17361789)比较均存在差异,rs11584340-G等位基因频率显著低于非洲人(YRI)和欧洲人(CEU)(P0.01);rs3126085-G等位基因频率显著低于CEU(P0.01)。结论延边朝鲜族rs11584340和rs3126085为强连锁不平衡;FLG基因SNP存在种族差异和民族差异;FLG基因rs11584340和rs3126085多态可能与中国延边地区朝鲜族AD易感性不相关。     

上海某中学青少年特应性皮炎和鱼鳞病FLG基因型的研究

目的 探讨青少年FLG基因型、了解特应性疾病患病率、发展进程及其FLG基因的关系。 方法 上海某中学334例11 ~ 19岁青少年作为研究样本,进行鱼鳞病、特应性皮炎（AD）、哮喘、鼻炎等特应性疾病的临床病史及体征观察、记录。285例进行了外周血采样及FLG基因高频突变筛查。5年后,进行样本人群随访,观察并记录各特应性疾病的临床症状及体征。 结果 5年前,334例青少年中AD19例（5.69%）,寻常性鱼鳞病14例（4.19%）,过敏性鼻炎36例（10.78%）,哮喘4例（1.20%）。在完成FLG基因测序的285例样本中,携带FLG基因高频突变者24例（8.42%）。5年后完成随访265例,失访69例（20.66%）,AD、鱼鳞病、过敏性鼻炎及哮喘的患病人数分别为13例（4.89%）、15例（5.64%）、27例（10.15%）、1例（0.38%）,原19例AD中6例进入完全缓解期,13例SCORAD评分明显下降,原36例过敏性鼻炎中9例症状消失。单纯AD、单纯鱼鳞病、AD合并鱼鳞病的FLG基因高频突变率分别为10.0%、55.6%、40.0%,且患鱼鳞病与FLG基因突变有关（P < 0.001）。结论 青少年中,FLG基因高频突变率为8.42%。FLG基因是寻常性鱼鳞病的半显性遗传因素,中间丝聚合蛋白的表达受多因素影响。     

丝聚合蛋白在寻常型鱼鳞病发病机制中的研究进展

寻常型鱼鳞病(ichthyosis vulgaris,IV)是一种常见的基因遗传性疾病,以干燥,鳞屑为特征,在人类遗传性疾病中占有较高发病率;寻常型鱼鳞病常与其他过敏性疾病相伴随,丝聚合蛋白(filaggrin,FLG)基因的突变导致表皮屏障功能的受损,可加重或者诱发过敏反应。鱼鳞病尚无满意的治疗方法,目前治疗以外用药为主,主要用润肤剂,因此,进一步探讨寻常型鱼鳞病的发病机制,研制新的、高效的药物,对治疗寻常型鱼鳞病及其相关疾病都具有重要意义。     

FLG基因RNAi慢病毒载体的构建与鉴定

目的构建人类中间丝聚合蛋白(filaggrin,FLG)基因慢病毒载体及观察慢病毒表达载体介导的RNA干扰RNAi对人HaCat细胞FLG表达的影响。方法应用基因工程技术筛选出3条针对FLG基因的RNAi靶序列,分别与GV115载体连接,构建3个重组慢病毒表达载体FLG-vshRNA 10154,FLG-vshRNA 10155,FLG-vshRNA 10156;将连接产物转化到DH5α感受态细胞,经PCR筛选阳性克隆、测序鉴定,将FLG-vshRNA,pHelper 1.0,pHelper 2.0共转染293T细胞,包装产生慢病毒颗粒并测定病毒滴度,将包装产生的3种重组慢病毒分别感染HaCat细胞,实时定量PCR检测HaCat细胞FLG mRNA表达。根据筛选的结果,选取最有效的载体进行病毒的大量包装。结果慢病毒载体PCR和测序结果表明3对碱基成功插入到预计位点,序列完全一致。慢病毒载体感染HaCat细胞后,FLG基因mRNA的表达量与未感染慢病毒的细胞组及空载体感染组相比均明显下降,下降程度达70%以上(P0.05)。3个慢病毒载体经包装产生的病毒滴度分别为1.2×109,1.5×109,1×109TU/mL。结论成功构建针对FLG基因的3个慢病毒载体FLG-vshRNA,体外感染HaCat细胞后可有效抑制FLG基因的表达。     

中间丝聚合蛋白基因多态性与特应性皮炎发病及临床表型的相关性

目的 探讨中间丝聚合蛋白(FLG)基因多态性与特应性皮炎(AD)发病及临床表型的相关性.方法 采用问卷调查的形式收集261例AD患者伴发过敏性鼻炎、哮喘病史和疾病严重度评分等资料,对部分患者进行混合食物过敏原和混合吸人性过敏原筛选、血清总IgE抗体和嗜酸性粒细胞阳离子蛋白水平检测.采用重叠PCR和DNA测序法对上述AD患者和276例健康对照FLG基因3号外显子17个多态性位点(R444G、T454A、P478S、H519N、D836D、S1482Y、A1805V、R1891Q、1961Q、S2166S、Y2194H、H2330H、D2339N、S2366T、E2398Q、K2444E、E2652D)进行基因分型.结果 二项逻辑回归分析和卡方检验未发现17种FLG多态位点与AD发病相关(均P＞0.05).H519N与AD伴发哮喘相关(x2=8.680,P=0.011),AA基因型可增加AD患者发生哮喘的风险(P=0.004,OR=1.061,95％ CI 1.016 ～ 1.109).S2366T和K2444E与AD患者食物敏感相关(x2值分别为6.520和6.121,P值分别为0.038和0.047),S2366T的GG+ GC基因型(P=0.012,OR=1.396,95％CI 1.054～1.849)和G等位基因(P=0.037,OR=1.350,95％CI 1.008～ 1.807)可提高AD患者食物敏感的风险.K2444E的AA+ AG基因型(P=0.013,OR=1.393,95％ CI 1.049 ～ 1.850)和G等位基因(P=0.028,OR=1.380,95％ CI 1.025 ～ 1.857)可提高AD患者食物敏感的风险.结论 中国汉族人群FLG基因多态性可能是一些AD相关临床表型的危险因素,H519N可能与AD伴发哮喘相关,S2366T和K2444E则可能与AD伴食物敏感相关.     

寻常型鱼鳞病一家系Filaggrin基因突变检测

目的探讨一家系寻常型鱼鳞病(ichthyosis vulgaris,IV)丝聚合蛋白(filaggrin,FLG)基因的突变。方法提取IV患者及其家庭成员和100例健康对照者基因组DNA,采用PCR及直接测序法,对FLG基因已报道的13个突变位点(3321delA,441delA,1249insG,E1795X,S3296X,R501X,2282del4,R2447X,S2889X,7945delA,3702delG,Q2417X,R4307X)进行测序。结果三代7位成员中4例IV患者同时检测到FLG(441delA)基因突变。结论患者FLG(441delA)基因突变可能导致其发病。     

特应性皮炎的易感基因与环境因素交互作用

特应性皮炎(atopic dermatitis,AD)是一种常见的慢性复发性炎性皮肤病,遗传与环境交互作用在其发病中起重要作用。研究发现FLG基因与金黄色葡萄球菌、花生过敏原、家庭养猫、多同胞数,神经肽S受体1基因与益生菌,谷胱甘肽硫转移酶基因与健康饮食、香烟烟雾暴露之间存在相互作用。深入挖掘遗传与环境因素的相关性,将为揭示AD发病机制提供新的契机。     

遗传性皮肤病

20091821四种遗传性鱼鳞病基因型与临床表型的相关性分析/何玉清(南方医大南方医院皮肤科),曾抗,张锡宝…∥中国皮肤性病学杂志.-2009,23(5).-267～270对四种鱼鳞病各1例患者进行临床表型分析及外周血DNA直接测序检测鱼鳞病FLG基因、STS基因、TGM1基因和K1,K10角蛋白基因的突变位点。①异常型鱼鳞病患者在FLG基因的外显子5的第278位有G-T突变,613位有G-A突变。②板层状鱼鳞病患者TGM1基因外显子3的第504位碱基有C-T突变,使第142位氨基酸由精氨酸转变为半胱氨酸,使348位氨基酸由精氨酸突变为终止密码,导致其编码的蛋白缺失了C端的470个氨基酸。③X     

丝聚蛋白与相关皮肤病发病机制的研究进展

丝聚蛋白通过参与角质形成细胞的终末角化过程,在表皮屏障中发挥重要作用.中间丝聚合蛋白基因突变引起蛋白表达下降,导致多种过敏性疾病.丝聚蛋白基因突变导致特应性皮炎,也是欧洲和亚洲人种寻常型鱼鳞病的主要诱发因素.丝聚蛋白基因与特应性皮炎发病的婴儿期或早期儿童期关系密切,而与晚期儿童期和成人期无关.有研究发现,小鼠体内缺氧诱导因子引起丝聚蛋白表达降低,提示丝聚蛋白可能不是疾病的单一致病因素.     

中间丝相关基因突变与皮肤病关联性的研究进展

中间丝相关蛋白是皮肤屏障中的一种重要的结构蛋白,对外界各种有害物质的入侵起到防御作用。中间丝相关蛋白相关基因突变或先天性缺陷,将导致这些蛋白质的异常表达,从而导致一系列以皮肤屏障功能损伤为特征的皮肤病发生。研究发现,中间丝相关蛋白基因突变与特应性皮炎以及寻常性鱼鳞病发病有明显的相关性;中间丝相关蛋白基因无义突变可能会降低镍接触性皮炎的发病年龄和增加对镍的敏感性;中间丝相关蛋白基因突变可能与斑秃、先天性厚甲综合征有关。总之,中间丝相关蛋白基因突变与多种皮肤疾病的发生有关联性,但目前中间丝相关蛋白基因突变是否为某一皮肤病的特征性致病因子仍需进一步研究。     

Loss-of-function mutations in the filaggrin gene and allergic contact sensitization to nickel

Allergic contact dermatitis is one of the most frequent dermatological problems affecting 7% of the general population. Impaired skin barrier function facilitates the penetration of contact allergens and irritants into the epidermal layer and is regarded as an important cofactor promoting the process of allergic contact sensitization. Filaggrin is crucial for the maintenance of the skin barrier function. Loss-of-function mutations within the filaggrin (FLG) gene are associated with skin barrier diseases such as ichthyosis vulgaris and atopic eczema (AE). To assess the impact of FLG on allergic contact sensitization and plausible intermediate traits, the two prevalent FLG mutations R501X and 2282del4 were typed in 1,502 individuals of the KORA C population-based cohort with extensive dermatologic phenotyping. Associations of FLG mutations with AE could be replicated. Strong associations were seen with dry skin, palmar hyperlinearity, and keratosis pilaris. In addition, an association with contact sensitization to nickel and contact sensitization to nickel combined with intolerance to fashion jewelry, but not with other contact allergens, was observed. From these data, we conclude that a genetically determined FLG deficiency manifests as dry skin and features of ichthyosis vulgaris. In addition, FLG deficiency may also represent a risk factor for contact sensitization to allergens.     

Profilaggrin, dry skin, and atopic dermatitis risk: size matters

Mutations in the FLG gene, which encodes profilaggrin, are known to be a major risk factor for atopic dermatitis as well as other atopic diseases and systemic allergies. New research, however, shows that intragenic copy number variation within FLG also represents an independent risk factor for atopic dermatitis. The new findings indicate that upregulating FLG protein levels by 5-10% may have clinical utility in improving the management of many patients with dry skin and atopy.     

Loss-of-function variants of the filaggrin gene are not major susceptibility factors for psoriasis vulgaris or psoriatic arthritis in German patients

Psoriasis vulgaris and atopic dermatitis share a number of features such as chronic cutaneous inflammation and disturbed epidermal barrier function. Genome-wide scans have revealed a conspicuous overlap of susceptibility loci for both diseases involving chromosomal regions 1q21, 3q21, 17q25, and 20p12. Recently, two loss-of-function variants in the gene encoding filaggrin at 1q21 were shown to be strongly associated with atopic dermatitis. In view of a possible genetic overlap of the two skin diseases, we investigated 375 patients suffering from psoriasis vulgaris, 375 patients with psoriatic arthritis, and 376 control probands. Moreover we directly studied expression of filaggrin in 10 patients suffering from psoriasis vulgaris. Our immunohistochemical analysis revealed a checkered pattern with alternating positive broadened or almost absent filaggrin expression. However, no association was found for the two variants of filaggrin (FLG). We conclude that despite a markedly altered filaggrin expression in psoriatic skin, loss-of-function variants of the FLG gene are neither associated with psoriasis vulgaris nor with psoriatic arthritis. The abnormal staining might reflect the altered epidermal differentiation. Our findings imply that the genetic background underlying the epidermal barrier defect in psoriasis is distinct from that found in atopic dermatitis.     

迟发型特应性皮炎的研究进展

特应性皮炎（AD）是一种炎症性皮肤病,与皮肤屏障功能受损密切相关。遗传因素、生活方式、环境因素的暴露都可导致该病的发生。尽管AD常见于婴幼儿,仍有成年后首次出现AD症状,被称为迟发型AD（AOAD）。与儿童期始发的AD相比,AOAD在分型、免疫学机制及与其他疾病的关联方面都存在着显著的差异。皮损分布与婴幼儿期初发的AD相似,但以亚急性和慢性皮炎为主要表现,呈现干燥的、肥厚的皮炎损害,少见渗出。Th1/Th2失衡及抗原提呈细胞的功能亢进是AD发生的免疫学基础。FLG基因突变会影响AD的发生,IL-13升高使FLG存在获得性的表达缺陷仅发生于成年人,提示了AOAD不同于婴幼儿期初发并迁延至成年期的AD。感染、皮肤及肠道菌群改变、吸烟等均可成为诱发AOAD的重要因素,因此在诊断AOAD时询问相关疾病史和吸烟史有助于AOAD的诊断。     

Skin prick test reactivity to aeroallergens by filaggrin mutation status

Background Studies have shown that filaggrin gene (FLG) mutations are positively associated with sensitization to aero allergens. We hypothesized that FLG mutations would also have an effect on the mean size of positive skin prick test (SPT) reactions as well as the number of positive reactions. Objective To investigate the effect of FLG mutations on the mean size and the number of positive SPT reactions, as well as the association with positive specific IgE. Methods A random sample of 3335 adults from the general population in Denmark was genotyped for the R501X and 2282del4 mutations in the FLG. SPT and specific IgE measurements to common aeroallergens were also performed. Results FLG mutations did not influence the mean size and number of positive SPT reactions. Also, no association was found between FLG mutations and specific IgE measurements. Conclusion Our findings suggest that FLG mutations alone are insufficient to cause secondary sensitization to allergens. The positive association seen in patients must be explained by a combination of further barrier abnormality caused by dermatitis as well as increased allergen exposure.     

Loss-of-function polymorphisms in the filaggrin gene are associated with an increased susceptibility to chronic irritant contact dermatitis: a case-control study

Background  Polymorphisms in the filaggrin (FLG) gene, which result in loss of filaggrin production, may alter the skin barrier and are a well-known predisposing factor for atopic dermatitis.
Objectives  As a compromised skin barrier and atopic dermatitis are risk factors for chronic irritant contact dermatitis (CICD), our objective was to determine whether polymorphisms in the FLG gene contribute towards susceptibility to occupational CICD.
Methods  In a case–control study, the FLG polymorphisms R501X and 2282del4 were determined in 296 patients with CICD. Two hundred and seventeen apprentices in vocational training for high-risk occupations for CICD were chosen as controls. Data on skin diseases and conditions were collected by dermatologists from patients and by means of questionnaires from controls.
Results  Heterozygotes for R501X and 2282del4, FLG null alleles, were more frequent among patients with CICD (12·5%) compared with controls (6·9%), resulting in an odds ratio of 1·91 (95% confidence interval 1·02–3·59). Among patients who were carriers of a FLG null allele, we found a higher lifetime prevalence of flexural eczema (62% vs. 46%; P  = 0·04) and a higher atopy score (13 vs. 10 points; P  = 0·05) compared with noncarriers. In the apprentice group, signs of dermatitis before the start of the vocational training were four times more prevalent in carriers (43%) than in noncarriers (10%; P  < 0·001).
Conclusions  Our study shows that FLG null alleles are associated with increased susceptibility to CICD; whether or not the FLG null allele is an independent risk factor needs further study.