Expression of hair keratins in the adult nail unit: an immunohistochemical analysis of the onychogenesis in the proximal nail fold, matrix and nail bed
Expression of hair keratins in the adult nail unit: an immunohistochemical analysis of the onychogenesis in the proximal nail fold, matrix and nail bed
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DOI：
10.1111/j.1365-2133.2004.06108.x
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发表时间：
2004-08-01
影响因子：
10.3
通讯作者：
Schweizer, J
中科院分区：
文献类型：
--
作者：
Perrin, C;Langbein, L;Schweizer, J
背景：近年来，复合角蛋白家族成员在人毛发生长期毛囊中的表达谱已被确定。为了填补这一空白，我们对成人指甲单位进行了免疫组织化学研究，通过对两种类型的9种头发角蛋白的特异性抗体，（hHa 2、hHb 2、hHa 5、hHb 5、hHa 1、hHb 1、hHb 6、hHa 4和hHa 8）以及三种上皮角蛋白方法用单克隆和多克隆角蛋白抗体分别检测甲醛固定的成人指甲石蜡切片。纵向以及横向sectionsinvestigated.Results我们的研究揭示了两种类型的上皮组织舱室的指甲单位。第一组包括甲上皮、甲下皮和甲床，只表达上皮角蛋白。虽然角蛋白K5，K17（基底）和K10（基底上）被发现在orthokeratinizing甲上皮和甲下膜，整个，甲床上皮细胞只表达K5和K17。第二种类型包括顶端和腹侧基质，表现出上皮和毛角蛋白表达的混合模式。因此，K5和K17在顶侧和腹侧基质的整个多层基底细胞隔室中表达;然而，在后者中，K5和K17也出现在上覆角化区的最下层。毛基质角蛋白hHb 5，但不是它的II型合作伙伴hHa 5，被认为是在整个角化区的顶端和腹侧基质，但也位于最上层的细胞层的基底室的腹侧基质，在那里它与K5和K17重叠。类似于它们在毛囊皮质中的顺序表达，毛发角蛋白hHa 1、hHb 1、hHb 6和hHa 4连续地在腹侧和（尽管不太明显）顶侧基质的角质生成区中表达，其中hHa 1起始于最低细胞层。hHa 8在毛囊的单个皮质细胞中的表达也保留在角质形成区的细胞中。在所谓的背基质区域，我们观察到两种组织学和组织化学上不同类型的上皮细胞：（i）显性类型，组织学上类似于甲上皮，相关的K5、K17和K10角蛋白模式明显延伸到顶端基质中，和（ii）次要类型，组织学上类似于假定的背侧基质，没有颗粒层和角质层，结论hHb 5与K5、K17在基底室最上层和腹侧基质角化带最下层细胞中共表达，提示该区域为腹侧基质前角化带。背侧基质中两种交替的组织学类型和角蛋白表达将该区域确定为甲上皮和顶侧基质之间的过渡区。最后，我们的数据清楚地表明，腹侧基质是甲板的主要来源。此外，混合的情况下，头发和上皮角蛋白，包括可证明的量的K10，在表层细胞的顶端基质，借给支持的概念，即背侧部分的指甲产生的顶端基质。
Background Recently, the expression profiles of the members of the complex hair keratin family have been determined in the human anagen hair follicle. In contrast, the details of hair keratin expression in the human nail unit are poorly known.Objectives In order to fill this gap, we have performed an immunohistochemical study of the adult human nail unit by means of specific antibodies against nine hair keratins of both types (hHa2, hHb2, hHa5, hHb5, hHa1, hHb1, hHb6, hHa4 and hHa8) as well as three epithelial keratins (K5, K17 and K10).Methods Formalin-fixed paraffin sections of adult nails were examined using monoclonal and polyclonal keratin antibodies, respectively. Longitudinal as well as transverse sections were investigated.Results Our study revealed two types of epithelial tissue compartments in the nail unit. The first comprised the eponychium and hyponychium and the nail bed, which expressed only epithelial keratins. While keratins K5, K17 (basal) and K10 (suprabasal) were found in the orthokeratinizing eponychium and hyponychium, throughout, the nail bed epithelium expressed only K5 and K17. The second type comprised the apical and ventral matrix which exhibited a mixed pattern of epithelial and hair keratin expression. Thus, K5 and K17 were expressed in the entire multilayered basal cell compartment of the apical and ventral matrix; however, in the latter, K5 and K17 also occurred in the lowermost layers of the overlying keratogenous zone. The hair matrix keratin hHb5, but not its type II partner hHa5, was seen in the entire keratogenous zone of the apical and ventral matrix, but was also located in the uppermost cell layers of the basal compartment of the ventral matrix, where it overlapped with K5 and K17. Similar to their sequential expression in the hair follicle cortex, hair keratins hHa1, hHb1, hHb6 and hHa4 were consecutively expressed in the keratogenous zone of both the ventral and, albeit less distinctly, apical matrix, with hHa1 initiating in the lowermost cell layers. The expression of hHa8 in only single cortex cells of the hair follicle was also preserved in cells of the keratogenous zone. In the region of the so-called dorsal matrix, we observed two histologically and histochemically distinct types of epithelia: (i) a dominant type, histologically similar to the eponychium and an associated K5, K17 and K10 keratin pattern which clearly extended into the apical matrix, and (ii) a minor type, histologically resembling the postulated dorsal matrix without a granular layer and a cuticle, and exhibiting extended K5 expression as well as hair keratin expression in superficial cells.Conclusions The coexpression of hHb5 with K5 and K17 in the uppermost cell layers of the basal compartment and the lowermost layers of the keratogenous zone of the ventral matrix prompts us to designate this region the prekeratogenous zone of the ventral matrix. The two alternating types of histology and keratin expression in the dorsal matrix identify this region as a transitional zone between the eponychium and the apical matrix. Finally, our data clearly show that the ventral matrix is the main source of the nail plate. In addition, the mixed scenario of hair and epithelial keratins, including demonstrable amounts of K10, in superficial cells of the apical matrix, lends support to the notion that the dorsal portion of the nail is generated by the apical matrix.