Versican gene: Regulation by the β-catenin signaling pathway plays a significant role in dermal papilla cell aggregative growth

Abstract

Dermal papilla cells (DPCs), which exhibit a multilayer aggregative growth character in in vitro culture, are closely related to induction of hair follicles (HFs) formation, and are associated with the development and cycle regulation of HFs. Versican, a large chondroitin sulfate proteoglycan and one of the major components of the extracellular matrix, plays an essential role in hair follicle formation. And also the Wnt/β-catenin signaling pathway performs a crutial function in induction during hair follicle growth and embryogenesis. To characterize the role of versican and β-catenin in regulating DPCs aggregative growth, and to explore the versican gene expression regulation mechanism by TCF-4/β-catenin signaling pathway. We first cultured DPCs at different passages, and detected the change in β-catenin and versican expression in DPCs of various passages by RT-PCR and Western blot. Then we knockdowned the versican and β-catenin gene, evaluated and verificated the binding capability of TCF-4/β-catenin to TOP elements in versican gene promoter region at varied passage DPCs by EMSA and ChIP Assay, finally observed the effect of Wnt/β-catenin pathway inhibition on DPC aggregative growth. With the increase of passage, DPCs lost the aggregative property, the versican mRNA and protein level in DPCs was on a gradual decline, while not significant declining tendency of β-catenin. The mRNA of both β-catenin and versican reduced simultaneously after β-catenin siRNA transfection. The binding ability of TCF-4/β-catenin of varied-passage DPCs to cultured versican promoters diminished with the increase of DPC passages. And versican inhibition or Wnt/β-catenin pathway blocking could both produce considerable effect on the aggregative growth of low-passage DPCs. Wnt/β-catenin signal transducting system regulates DPC aggregative growth through modifying versican expression by means of acting on the versican gene upstream promoter.