Abstract
BackgroundHair follicles are an appendage of the vertebrate epithelium in the skin that arise from the embryonic ectoderm and regenerate cyclically during adulthood. Dermal papilla cells (DPCs) are the key dermal component of the hair follicle that directly regulate hair follicle development, growth and regeneration. According to recent studies, miRNAs play an important role in regulating hair follicle morphogenesis and the proliferation, differentiation and apoptosis of hair follicle stem cells.ResultsThe miRNA expression profile of the DPCs from Rex rabbits with different hair densities revealed 240 differentially expressed miRNAs (|log2(HD/LD)| > 1.00 and Q-value≤0.001). Among them, ocu-miR-205-5p was expressed at higher levels in DPCs from rabbits with low hair densities (LD) than in rabbits with high hair densities (HD), and it was expressed at high levels in the skin tissue from Rex rabbits (P < 0.05). Notably, ocu-miR-205 increased cell proliferation and the cell apoptosis rate, altered the progression of the cell cycle (P < 0.05), and modulated the expression of genes involved in the PI3K/Akt, Wnt, Notch and BMP signalling pathways in DPCs and skin tissue from Rex rabbits. It also inhibited the phosphorylation of the CTNNB1 and GSK-3β proteins, decreased the level of the noggin (NOG) protein, and increased the level of phosphorylated Akt (P < 0.05). A significant change in the primary follicle density was not observed (P > 0.05), but the secondary follicle density and total follicle density (P < 0.05) were altered upon interference with ocu-miR-205-5p expression, and the secondary/primary ratio (S/P) in the ocu-miR-205-5p interfered expression group increased 14 days after the injection (P < 0.05).ConclusionsIn the present study, ocu-miR-205 promoted the apoptosis of DPCs, altered the expression of genes and proteins involved in the PI3K/Akt, Wnt, Notch and BMP signalling pathways in DPCs and skin from Rex rabbits, promoted the transition of hair follicles from the growth phase to the regression and resting phase, and altered the hair density of Rex rabbits.
Highlights
Hair follicles are an appendage of the vertebrate epithelium in the skin that arise from the embryonic ectoderm and regenerate cyclically during adulthood
Dermal papilla cells (DPCs) show a complex miRNA expression pattern The varieties of miRNAs in DPCs from 30-day-old Rex rabbits with lower and higher hair densities (Additional file 1) were studied by subjecting RNA samples with a high integrity and qualified quality (Additional file 2) to high-throughput small RNA sequencing using the BGISEQ-500 platform. 37,930,744, 39,442,011, 40,965,907, 38,502,653, 40,622,117 and 41,149,163 clean reads were obtained from the six samples (Additional file 3), and the majority of clean reads had a length of 23 nucleotides (Additional file 4)
Specific Gene Ontology (GO) terms of the target genes mainly involved in the biological process (BP), cellular component (CC) and molecular function (MF) categories
Summary
Hair follicles are an appendage of the vertebrate epithelium in the skin that arise from the embryonic ectoderm and regenerate cyclically during adulthood. MiRNAs play an important role in regulating hair follicle morphogenesis and the proliferation, differentiation and apoptosis of hair follicle stem cells. The Wnt signalling pathway regulates epithelial morphogenesis, hair follicle development and cell differentiation. The BMP signalling pathway is involved in embryonic skin appendage organ morphogenesis and postnatal hair follicle growth [7]. Dermal papilla cells (DPCs) is the key dermal component of the hair follicle, and it can directly regulate hair follicle development, growth and regeneration [11]. Signal exchange between DPCs and hair follicle stem cells at telophase is the key to initiating the hair follicle cycle [13]
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