The Role Of H3K27me3 On The Cyclic Regenesis Of Hair Follicle From Shaanbei White Cashmere Goats

Cashmere goats,as one of the important economic animals,are famous to produce cashmere.It has been the focus on improving the yield and quality of cashmere for researchers and producers.The cyclic development of hair follicles directly affects cashmere production and quality,which is regulated by multiple genes and signaling pathways.Epigenetic modifications play a crucial role in coordinating changes of gene expression in vivo and responding to environmental changes.Among various epigenetic modifications,the effects of histone modifications on the changes of hair follicle cycle have been reprted in mice,but it was few for cashmere goats.H3K27me3,as one of the important histone modifications,has an important regulatory role in maintaining normal hair follicle development in mammals.Therefore,this study mainly explored the roles of H3K27me3 in hair follicle cyclic regeneration of cashmere goats.The results will provide highlights for improving the quality and efficiency of cashmere goats.In this study,three adult Shaanbei white cashmere goats were selected as the research objects,and their skin tissue samples were collected in anagen,catagen and telogen,respectively.Chromatin immunoprecipitation followed by sequencing(ChIP-seq)technology was used to analyze the modification ability of H3K27me3 for functional genes in different development periods of hair follicle,screen differential binding sites and annotate genes function.RNA-seq technology was used to analyze the genes differences in different development periods of hair follicle.Combined analysis of ChIP-seq and RNA-seq,potential target genes directly affected by H3K27me3 were screened and the regulatory mechanism of H3K27me3 on genes related to hair follicle development was analyzed.The main experimental results were as follows:1.ChIP-seq analysis showed that H3K27me3 was mainly enriched in the TSS region of genes and had a dynamic modification mode during the development cycle of hair follicle of Shaanbei White Cashmere Goats.It appeared a hypermethylated state for H3K27me3 modification in anagen,a hypomethylated state in catagen and Intermediate level in telogen.By the analysis of differential binding sites and gene annotation of peaks located in promoter region,it revealed a total of 7946 differentially modified genes(DMGs)between anagen and catagen,2419 DMGs between anagen and telogen,and 397 DMGs between catagen and telogen.These DMGs could participate in cellular,bioregulatory,developmental and metabolic processes,and stimulus response,as well as were involved in multiple signaling pathways related to hair follicle cycle development such as MAPK,Hippo,Rap1 and Focal adhesion by GO and KEGG enrichment analysis.2.RNA-seq analysis showed 1301 differentially expressed genes(DEGs)in different developmental periods of the hair follicle of Shaanbei White Cashmere Goats.Among them,there were 1147 DEGs between anagen and catagen,61 DEGs between anagen and telogen,and 178 DEGs between catagen and telogen.GO and KEGG functional annotation analysis showed that these DEGs were also involved in response to stimulation,bioregulation,development and metabolism,as well as PI3K-Akt,Wnt,AMPK and Rap1 signaling pathways and Focal adhesion,which were related to hair follicle cycle development.The key genes potentially involved in hair follicle cycle development were identified,including SOX9,LHX2,LGR5,DBP,NR1D1,SOCS3 and NR4A1.3.Combined ChIP-seq and RNA-seq analysis,a total of 550 potential target genes directly regulated by H3K27me3 were found,which were mainly from the difference between anagen and catagen.Compared with catagen,histone hypermethylation modifications occurred mainly in anagen,where 273 DEGs were low-expressed and 274 were high-expressed.The highly differentially expressed genes,COL1A1,NR4A1,SOCS3,ETS1,and SERPINE1,were lowly-expressed and associated with apoptosis.These genes were more conducive to the regeneration of hair follicles during anagen and the maintenance of follicle cell homeostasis in catagen.The genes KRT17,SOX9,LGR5,LHX2,DBP and NR1D1,highly expressed in anagen,were associated with cell proliferation and hair follicle cycle development.Through predicting the transcription factor binding motifs at the H3K27me3 binding sites,it was found that H3K27me3 might affect gene expression by influencing the binding of Sp/KLF family repressors on target genes.In summary,the cyclic development of hair follicles in Shaanbei white cashmere goats had been associated with gene expression changes by the dynamic modification of H3K27me3 on hair follicle development,which showed high modification of H3K27me3 in anagen,low modification in catagen,and gradually increasing modification of H3K27me3 in telogen.This feature was essential to maintain the orderly changes of hair follicles throughout the development cycle in goats.This study provided a new idea to investigate the regulatory mechanism of hair follicle growth and development in cashmere goats,and provided a scientific basis for improving the quality of cashmere.