The expression of human loricrin gene

Loricrin是角化细胞包膜（CE）的主要成分。Loricrin首先出现在角透明素颗粒中，随后并入CE。顺便说一下，在各种遗传性角化疾病中，责任基因的点突变仅在大疱性先天性鱼鳞状红皮病、某些类型的板层性鱼鳞病、某些类型的掌跖角化病、Sjogren-Larsson综合征和Vohwinkel综合征中被发现。Vohwinkel综合征现在被认为是由于loricrin基因的点突变。由于loricrin是CE的主要成分，了解loricrin基因在正常和异常角化条件下的表达，不仅有助于Vohwinkel综合征的诊断和治疗，而且有助于对各种角化疾病的深入了解。在高钙培养基中培养FRSK细胞、正常人表皮角质细胞（NHEK）、Pam 212和HaCaT细胞，观察是否形成CE。我们发现HaCaT细胞在高钙培养基中可以形成CE。我们还检测了loricrin和谷氨酰胺转胺酶1的表达。众所周知，loricrin在NHEK细胞中几乎检测不到。相反，loricrin在高钙培养基培养的HaCaT细胞中大量表达。因此，在高钙培养基中培养的HaCaT细胞类似于活体表皮。因此HaCaT细胞非常适合于loricrin表达和表皮角化的研究。

Loricrin is a major constituent of cornified cell envelope (CE). Loricrin appears at keratohyalin granules at first and is subsequently incorporated into CE.By the way, amongst various hereditary keratinizing disorders, the point mutations of responsible genes were identified only in bullous congenital ichthyosiform erythroderma, some types of lamellar ichthyosis, some types of palmoplantar keratoderma, Sjogren-Larsson syndrome and Vohwinkel syndrome. Vohwinkel syndrome is now thought to be due to the point mutation of loricrin gene. Because loricrin is the major constituent of CE,to understand the expression of loricrin gene in normal and abnormal keratinizing conditions not only facilitates the diagnosis and therapy of Vohwinkel syndrome but also encourages the deep understanding of wide variety of keratinizing disorders. We cultured FRSK cells, normal human epidermal kerationcytes (NHEK), Pam 212 and HaCaT cells in high calcium medium and checked whether CE was formed or not. We found HaCaT cells cultured in high calcium medium could form CE.We also checked the expression of loricrin and transglutaminase 1. It is well known that loricrin is hardly detectable in NHEK cells. In contrast loricrin is abundantly expressed in HaCaT cells cultured in high calcium medium. Thus HaCaT cells cultured in high calcium medium resemble in vivo epidermis. Thus HaCaT cells are very suitable for the research in the expression of loricrin and epidermal keratinization.