Analysis of histological and microRNA profiles changes in rabbit skin development

Abstract

The periodic regrowth of rabbit fur is economically important. Here, we aimed to characterise the histological traits and microRNA (miRNA) expression profiles in the skin tissue of Wan Strain Angora rabbits at different weeks after plucking. Haematoxylin-eosin staining showed that hair follicles were in the telogen phase in the first week, while they were in the anagen phase from the fourth to twentyfourth weeks. In addition, two small RNA libraries derived from skin samples of Wan Strain Angora rabbits at telogen and anagen stages yielded over 24 million high-quality reads. Specifically, 185 miRNAs were differentially expressed between the telogen and anagen phases. The function of the differentially expressed miRNAs was explored by comparing them with known mammalian miRNAs and by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis of their predicted targets. Five new functional miRNAs were validated using quantitative real-time PCR. Moreover, the fibroblast growth factor 5 (FGF5) gene was verified to be a target of conservative_NC_013672.1_9290 and conservative_NC_013675.1_10734. We investigated differential miRNA profiles between the telogen and anagen phases of the hair cycle and our findings provide a basis for future studies focusing on the mechanisms of miRNA-mediated regulation of rabbit hair follicle cycling.The growth and development of hair follicles are cyclical throughout a rabbit's life. In adults, hair follicles undergo cyclical bouts of growth (anagen), destruction (catagen), and rest (telogen), which are collectively known as the hair cycle 1-4 . Each growth period has a specific activated/silenced gene expression pattern 5 . Hence, understanding gene expression patterns can help to elucidate the regulatory mechanisms of the rabbit hair cycle.Hair follicle development is controlled at several levels, including epigenetic regulation and transcription factor-induced signalling 6,7 . miRNAs are small (22 nucleotides) noncoding regulatory RNAs that reduce stability and/or the translation of specific mRNA targets with full or partial complementary sequences 8-10 . However, compared with other mammals, including humans (Homo sapiens), mice (Mus musculus), and rats (Rattus norvegicus), relatively few miRNAs in rabbits have been verified and deposited in the public miRBase database. Thus, it is necessary to clarify the roles of miRNAs in the regulation of the hair cycle in rabbits.Emerging evidence indicates that miRNAs are involved in skin and hair follicle development. miRNA/mRNA regulatory networks are reported to be involved in the regulation of hair follicle development and epidermal homeostasis 11 . In particular, hair follicle development is regulated by miR-195-5p-induced inhibition of the Wnt/β-catenin pathway through targeting LRP6 and signature genes of Wnt signalling 12 . Furthermore, miR-339-5p negatively regulates loureirin A-induced hair follicle stem cell differentiation by targeting DLX5 13 . In addition, miR-31 is a marker of the hair growth phase, and its loss p...

Atlas of Prenatal Hair Follicle Morphogenesis Using the Pig as a Model System

“…Generally, prenatal HF morphogenesis development has been divided into three main periods. The morphological characteristics of hair placode, DC, DP, etc., at different periods are nearly the same in human (Muller et al, 1991), mice (Schneider et al, 2009), sheep (Zhang et al, 2019), rabbit (Ding et al, 2020) and, based on the current study, even in pig. However, the hair type and commence time points of each HF morphogenesis development stage has been shown to vary largely, e.g., secondary HF in sheep and rabbit could make the HF morphogenesis complicated, thus making them not ideal model systems for human HF research.…”

Rabbits – their domestication and molecular genetics of hair coat development and quality

“…Recent studies carried out on Wan Strain Angora rabbits (Ding et al . 2020) found that the hair follicles were in the short telogen phase in the first week after plucking and were in anagen phase from the fourth to twenty‐fourth weeks. The long anagen phase of the hair cycle promoted the continuous growth of Wan Strain Angora rabbit hair.…”

Analysis of histology and long noncoding RNAs involved in the rabbit hair follicle density using RNA sequencing

“…Hair follicle development is a complex morphogenetic process and undergoes periodic stages of growth (anagen), regression (catagen), and relative quiescence (telogen) [ 10 – 12 ]. The process of hair follicle formation and differentiation relies on many regulating molecules including messenger RNAs (mRNAs) and micro RNAs (miRNAs) [ 13 – 15 ], as well as a variety of signalling systems, such as the Wnt, Notch, bone morphogenetic protein (BMP), and fibroblast growth factor (FGF) pathways [ 16 – 21 ]. LncRNAs are RNA transcripts longer than 200 nucleotides that lack open reading frames (ORF) and protein-coding capabilities [ 22 ].…”