Skin transcriptome reveals the intrinsic molecular mechanisms underlying hair follicle cycling in Cashmere goats under natural and shortened photoperiod conditions

Min Yang,Yuehui Ma,Yabin Pu,Shen Song,Weijun Guan,Xuexue Liu,Marhaba Rouzi,Xiaohong He,Kunzhe Dong,Qianjun Zhao,Xiaofei Chen,Lin Jiang

doi:10.1038/s41598-017-13986-w

Abstract

The growth of cashmere exhibits a seasonal pattern arising from photoperiod change. However, the underlying molecular mechanism remains unclear. We profiled the skin transcriptome of six goats at seven time points during hair follicle cycling via RNA-seq. The six goats comprised three goats exposed to a natural photoperiod and three exposed to a shortened photoperiod. During hair cycle transition, 1713 genes showed differential expression, and 332 genes showed a pattern of periodic expression. Moreover, a short photoperiod induced the hair follicle to enter anagen early, and 246 genes overlapped with the periodic genes. Among these key genes, cold-shock domain containing C2 (CSDC2) was highly expressed in the epidermis and dermis of Cashmere goat skin, although its function in hair-follicle development remains unknown. CSDC2 silencing in mouse fibroblasts resulted in the decreased mRNA expression of two key hair-follicle factors, leading to reduced cell numbers and a lower cell density. Cashmere growth or molting might be controlled by a set of periodic regulatory genes. The appropriate management of short light exposure can induce hair follicles to enter full anagen early through the activation of these regulators. The CSDC2 gene is a potentially important transcription factor in the hair growth cycle.

Highlights

The hair follicle (HF) is a dynamic mini-organ that experiences fundamental and cyclical organ transformations throughout its lifespan[1]
The sections obtained from August to October showed a visible inner root sheath, dense HFs and sebaceous glands, which are consistent with morphogenesis during anagen (Figs 1D and S1)
In the sections collected in January, HF condensation and apoptosis of epithelial cells and the outer root sheath were observed, indicating that the SHFs were at the catagen stage (Figs 1E and S1)

Summary

Introduction

The hair follicle (HF) is a dynamic mini-organ that experiences fundamental and cyclical organ transformations throughout its lifespan[1]. Cashmere growth in Cashmere goats is synchronized annually in response to changes in daylight[7] This variation in regenerative hair patterns depends on both intrinsic molecular mechanism and the external environment (i.e., daylight)[6,8,9]. The seasonal rhythm of cashmere growth makes the Cashmere goat an ideal animal model to identify the molecular mechanism underlying HF cycling in response to seasonal photoperiod alterations. To comprehensively investigate the intrinsic molecular mechanism of HF cycling and the effects of shortened photoperiod on HFs, we performed RNA-seq analysis of skin tissues from six cashmere goats at seven time points. To identify the key factors related to cashmere growth, we applied multiple methods, including principle component analysis (PCA), differential expression (DE) analysis, hierarchical clustering analysis and gene ontology (GO) enrichment. This study provides insight into the transition mechanism of HF cycles and the factors that regulate HF cycling and development

Methods

Results

Discussion

Conclusion