Cashmere goat is known for its precious undercoat. Being photoperiod-dictated, cashmere growth has been studied focusing mainly on hair follicle cycle phases (anagen, catagen and telogen). An accurate molecular knowledge of the goat hair follicle cycle, disentangling gene expression changes during phases and recognizing timing boundaries, could be useful to improve cashmere goat management and ultimately cashmere production. To better describe goat’s hair follicle transcriptome we applied RNA-sequencing to isolated hair follicles from five Italian cashmere goats, during the anagen and catagen phase, identifying total of 214 differentially expressed genes (DEGs): 97 were up-regulated while 117 were down-regulated in catagen with respect to anagen. Gene Ontology and pathway analysis were performed. We detected 144 significant pathways spanning from estrogen, pluripotency of stem cells, thermogenesis and fatty acid metabolism that were strongly expressed during the hair follicle phases analysed. Finally, we validated promising DEGs by RT-qPCR in the same set of samples as well as in hair follicles and entire skin biopsies of another cashmere goats cohort accounting for early anagen, anagen, early catagen, and catagen phases. As in the isolated hair follicles, some target genes were homogenously modulated during the four hair follicle phases. Ceruloplasmin (CP) and Keratin 4 (K4), confirmed their clear cut expression between growing and resting phase. In fact, K4 was almost absent in catagen phases while CP was barely expressed in anagen phases. In particular, the strong expression of K4 in early anagen makes it an eligible marker to track the beginning of a new hair cycle, and therefore defining the optimum time for cashmere harvesting.

中文翻译：

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揭示绒山羊毛囊生物学：从形态分析到转录组景观。

绒山羊以其珍贵的底毛而闻名。由于光周期决定，羊绒生长的研究主要集中在毛囊周期阶段（毛发生长初期、毛发生长中期和毛发生长终期）。对山羊毛囊周期的准确分子了解，解开各个阶段的基因表达变化并识别时间界限，可能有助于改善绒山羊管理并最终提高羊绒产量。为了更好地描述山羊毛囊转录组，我们对五只意大利绒山羊在毛发生长初期和毛发生长后期阶段的分离毛囊进行了 RNA 测序，鉴定出总共 214 个差异表达基因 (DEG)：97 个上调，117 个下调。相对于毛发生长初期，在毛发生长中期受到调节。进行了基因本体论和通路分析。我们检测到 144 条重要通路，涵盖雌激素、干细胞多能性、生热作用和脂肪酸代谢，这些通路在分析的毛囊阶段强烈表达。最后，我们通过 RT-qPCR 在同一组样本以及另一个绒山羊群体的毛囊和整个皮肤活检中验证了有前景的 DEG，这些绒山羊群体包括毛发生长初期、毛发生长初期、毛发生长早期和毛发生长后期阶段。与分离的毛囊一样，一些靶基因在四个毛囊阶段受到同质调节。铜蓝蛋白 (CP) 和角蛋白 4 (K4) 证实了它们在生长期和休眠期之间的明确表达。事实上，K4 在毛发生长中期几乎不存在，而 CP 在毛发生长初期几乎不表达。特别是，K4 在生长期早期的强表达使其成为追踪新毛发周期开始的合格标记，从而确定羊绒收获的最佳时间。