Phenotypic analysis of keratinocyte-specific PBP null mice

角化细胞特异性PBP缺失（PBP^<epi-/->）小鼠的毛囊间表皮是棘皮的，PBP^<epi-/->小鼠的毛发循环自发重复，直到约6月龄，这在野生型小鼠中没有发生。免疫组织化学分析一致显示，PBP^<epi-/->表皮的角质形成细胞增殖性更强。流式细胞术分析显示，出生几个月后，PBP^<epi-/->小鼠毛囊膨出干细胞数量减少。这些结果表明，PBP在毛囊干细胞的静止中起着关键作用，PBP^<epi-/->小鼠的毛囊干细胞在持续提供过多的角质形成细胞后，随着年龄的增长而耗尽，导致毛发周期异常频繁重复和毛囊间表皮过度增生。

The interfollicular epidermis of keratinocyte-specific PBP null (PBP^<epi-/->) mice was acanthotic and the hair cycle of PBP^<epi-/-> mice was spontaneously repeated until about 6 months of age, which does not occur in wild-type mice. Consistently, immunohistochemical analysis showed keratinocytes in the epidermis of PBP^<epi-/-> were more proliferative. Flow cytometric analysis revealed that the numbers of hair follicle bulge stem cells were reduced in PBP^<epi-/-> mice from a few months after birth. From these results, it is suggested that PBP plays critical roles in the quiescence of hair follicle stem cells and that the follicular stem cells of PBP^<epi-/-> mice are depleted with age after continuously supplying excessive keratinocytes for the abnormally frequent repeat of hair cycling and the hyperproliferative interfollicular epidermis.