Micro-RNA-31 controls hair cycle-associated changes in gene expression programs of the skin and hair follicle

Knockdown of miR-361-5p promotes the induced activation of SHF-stem cells through FOXM1 mediated Wnt/β-catenin pathway in cashmere goats

The inducing activation event of secondary hair follicle (SHF)-stem cells is considered a key biological process in the SHF regeneration, and the morphogenesis of cashmere fiber in cashmere goats. The miR-361-5p was essentially implicated in the induced activation of SHF-stem cells of cashmere goats, but its functional mechanisms are unclear. Here, we confirmed miR-361-5p was significantly downregulated in anagen SHF bugle of cashmere goats compared with that at telogen, and miR-361-5p expression was significantly lower in SHF-stem cells after activation than its counterpart before activation. Further, we found that miR-361-5p could negatively regulate the induced activation event of SHF-stem cells in cashmere goats. Mechanistically, through dual-luciferase reporter assays, miR-361-5p specifically bound with FOXM1 mRNA in SHF-stem cells of cashmere goats and negatively regulated the expression of FOXM1 gene. Also, through overexpression/knockdown analysis of FOXM1 gene, our results indicated that FOXM1 upregulated the expression of Wnt/β-catenin pathway related genes in SHF-stem cells. Moreover, based on TOP/FOP-flash Wnt report assays, the knockdown of miR-361-5p promotes the Wnt/β-catenin pathway activation through upregulating the FOXM1 expression in SHF-stem cells. Finally, we demonstrated that miR-361-5p negatively regulated the induced activation of SHF-stem cells through FOXM1 mediated Wnt/β-catenin pathway in cashmere goats.

MicroRNA expression profiles reveal wool development and fineness regulation in Gansu alpine fine-wool sheep

The development of wool has a complex regulatory mechanism both influenced by genetic and environmental factors. MicroRNAs (miRNA) were involved in various biological processes of animals, and may play an important role in the regulation of wool development. In this study, we comprehensively analyzed and identified the histological parameters of hair follicles, as well as the miRNAs, target genes, pathways, and Gene Ontology terms related to wool fineness regulation and wool growth and development using HE staining and RNA-Seqs methods. Both coarse (group C, mean fiber diameter (MFD) = 22.26 ± 0.69 μm, n = 6) and fine (group F, MFD = 16.91 ± 0.29 μm, n = 6) of Gansu alpine fine-wool sheep with different wool fineness were used in this study. The results showed that the primary follicle diameter and secondary wool fiber diameter in group C were significantly higher than those in group F (P < 0.05). And the number of primary and secondary hair follicles in group C was significantly lower than that in group F (P < 0.05). Furthermore, a total of 67 DE miRNAs and 290 potential DE miRNAs target genes were screened in the skin tissues of sheep from groups F and C, and some potential target genes related to wool fineness regulation were screened, such as CDH2, KRT82, FOXN1, LOC101106296, KRT20, MCOLN3, KRT71, and TERT. These genes were closely related to Glutathione metabolism, epidermal cell differentiation, keratinization, and regulation of hair cycle. Moreover, the regulatory network of miRNAs-mRNAs suggested that miRNAs (miR-129-x, novel m0079-3p, miR-2484-z, novel m0025-5P, etc.) may play a key role in the wool development and wool fineness regulation of Gansu alpine fine-wool sheep. In summary, this study expands the existing miRNAs database and provides new information for studying the regulation of wool development in Gansu alpine fine wool sheep.

MicroRNA-181a Targets GNAI2 and Affects the Proliferation and Induction Ability of Dermal Papilla Cells: The Potential Involvement of the Wnt/β-Catenin Signaling Pathway

Wool is generated by hair follicles (HFs), which are crucial in defining the length, diameter, and morphology of wool fibers. However, the regulatory mechanism of HF growth and development remains largely unknown. Dermal papilla cells (DPCs) are a specialized cell type within HFs that play a crucial role in governing the growth and development of HFs. This study aims to investigate the proliferation and induction ability of ovine DPCs to enhance our understanding of the potential regulatory mechanisms underlying ovine HF growth and development. Previous research has demonstrated that microRNA-181a (miR-181a) was differentially expressed in skin tissues with different wool phenotypes, which indicated that miR-181a might play a crucial role in wool morphogenesis. In this study, we revealed that miR-181a inhibited the proliferation and induction ability of ovine DPCs by quantitative Real-time PCR (qRT-PCR), cell counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, and alkaline phosphatase staining. Then, we also confirmed G protein subunit alpha i2 (GNAI2) is a target gene of miR-181a by dual luciferase reporter assay, qRT-PCR, and Western blot, and that it could promote the proliferation and induction ability of ovine DPCs. In addition, GNAI2 could also activate the Wnt/β-Catenin signaling pathway in ovine DPCs. This study showed that miR-181a can inhibit the proliferation and induction ability of ovine DPCs by targeting GNAI2 through the Wnt/β-Catenin signaling pathway.

MiR-23b and miR-133 Cotarget TGFβ2/NOTCH1 in Sheep Dermal Fibroblasts, Affecting Hair Follicle Development

Wool is produced and controlled by hair follicles (HFs). However, little is known about the mechanisms involved in HF development and regulation. Sheep dermal fibroblasts (SDFs) play a key role in the initial stage of HF development. Analyzing the molecular mechanism that regulates early HF development in superfine wool sheep is of great importance for better understanding the HF morphogenesis process and for the breeding of fine wool sheep. Here, we show that two microRNAs (miRNAs) affect the development of HFs by targeting two genes that are expressed by SDFs. Meanwhile, the overexpression and inhibition of oar-miR-23b and oar-miR-133 in SDFs cells and cell proliferation, apoptosis, and migration were further detected using a CCK-8 assay, an Annexin V-FITC assay, a Transwell assay, and flow cytometry. We found that oar-miR-23b, oar-miR-133, and their cotarget genes TGFβ2 and NOTCH1 were differentially expressed during the six stages of HF development in superfine wool sheep. Oar-miR-23b and oar-miR-133 inhibited the proliferation and migration of SDFs and promoted the apoptosis of SDFs through TGFβ2 and NOTCH1. oar-miR-23b and oar-miR-133 inhibited the proliferation and migration of SDFs by jointly targeting TGFβ2 and NOTCH1, thereby inhibiting the development of superfine wool HFs. Our research provides a molecular marker that can be used to guide the breeding of ultrafine wool sheep.

Identification of Potential miRNA-mRNA Regulatory Network Associated with Growth and Development of Hair Follicles in Forest Musk Deer

In this study, sRNA libraries and mRNA libraries of HFs of FMD were constructed and sequenced using an Illumina HiSeq 2500, and the expression profiles of miRNAs and genes in the HFs of FMD were obtained at the anagen and catagen stages. In total, 565 differentially expressed unigenes (DEGs) were identified, 90 of which were upregulated and 475 of which were downregulated. In the BP category of GO enrichment, the DEGs were enriched in the processes related to HF development and differentiation, including the hair cycle regulation and processes, HF development, skin epidermis development, regulation of HF development, skin development, the Wnt signaling pathway, and the BMP signaling pathway. Through KEGG analysis it was found that DEGs were significantly enriched in pathways associated with HF development and growth. A total of 186 differentially expressed miRNAs (DEmiRNAs) were screened (p < 0.05) in the HFs of FMD at the anagen stage vs. the catagen stage, 33 of which were upregulated and 153 of which were downregulated. Through DEmiRNA-mRNA association analysis, we found DEmiRNAs and target genes that mainly play regulatory roles in HF development and growth. The enrichment analysis of DEmiRNA target genes revealed similarities with the enrichment results of DEGs associated with HF development. Notably, both sets of genes were enriched in key pathways such as the Notch signaling pathway, melanogenesis, the cAMP signaling pathway, and cGMP-PKG. To validate our findings, we selected 11 DEGs and 11 DEmiRNAs for experimental verification using RT-qPCR. The results of the experimental validation were consistent with the RNA-Seq results.

MicroRNA-148a Controls Epidermal and Hair Follicle Stem/Progenitor Cells by Modulating the Activities of ROCK1 and ELF5

Skin and hair development is regulated by complex programs of gene activation and silencing and microRNA-dependent modulation of gene expression to maintain normal skin and hair follicle development, homeostasis, and cycling. In this study, we show that miR-148a, through its gene targets, plays an important role in regulating skin homeostasis and hair follicle cycling. RNA and protein analysis of miR-148a and its gene targets were analyzed using a combination of in vitro and in vivo experiments. We show that the expression of miR-148a markedly increases during telogen (bulge and hair germ stem cell compartments). Administration of antisense miR-148a inhibitor into mouse skin during the telogen phases of the postnatal hair cycle results in accelerated anagen development and altered stem cell activity in the skin. We also show that miR-148a can regulate colony-forming abilities of hair follicle bulge stem cells as well as control keratinocyte proliferation/differentiation processes. RNA and protein analysis revealed that miR-148a may control these processes by regulating the expression of Rock1 and Elf5 in vitro and in vivo. These data provide an important foundation for further analyses of miR-148a as a crucial regulator of these genes target in the skin and hair follicles and its importance in maintaining stem/progenitor cell functions during normal tissue homeostasis and regeneration.

The Identification and Characteristics of miRNAs Related to Cashmere Fiber Traits in Skin Tissue of Cashmere Goats

microRNAs (miRNAs) are involved in the regulation of biological phenomena by down-regulating the expression of mRNAs. In this study, Liaoning cashmere (LC) goats (n = 6) and Ziwuling black (ZB) goats (n = 6) with different cashmere fiber production performances were selected. We supposed that miRNAs are responsible for the cashmere fiber trait differences. To test the hypothesis, the expression profiles of miRNAs from the skin tissue of the two caprine breeds were compared using small RNA sequencing (RNA-seq). A total of 1293 miRNAs were expressed in the caprine skin samples, including 399 known caprine miRNAs, 691 known species-conserved miRNAs, and 203 novel miRNAs. Compared with ZB goats, 112 up-regulated miRNAs, and 32 down-regulated miRNAs were found in LC goats. The target genes of the differentially expressed miRNAs were remarkably concentrated on some terms and pathways associated with cashmere fiber performance, including binding, cell, cellular protein modification process, and Wnt, Notch, and MAPK signaling pathways. The miRNA-mRNA interaction network found that 14 miRNAs selected may contribute to cashmere fiber traits regulation by targeting functional genes associated with hair follicle activities. The results have reinforced others leading to a solid foundation for further investigation of the influences of individual miRNAs on cashmere fiber traits in cashmere goats.

Regulation of secondary hair follicle cycle in cashmere goats by miR-877-3p targeting IGFBP5 gene

Cashmere, a highly valuable animal product derived from cashmere goats, holds significant economic importance. MiRNAs serve as crucial regulators in the developmental processes of mammalian hair follicles. Understanding the regulation of miRNAs during the hair follicle cycle is essential for enhancing cashmere quality. In this investigation, we employed high-throughput sequencing technology to analyze the expression profiles of miRNAs in the secondary hair follicles of Jiangnan cashmere goats at different stages. Through bioinformatics analysis, we identified differentially expressed miRNAs (DE miRNAs). The regulatory relationships between miRNAs and their target genes were verified using multiple techniques, including RT-qPCR, western blot, Dual-Luciferase Reporter, and CKK-8 assays. Our findings revealed the presence of 193 DE miRNAs during various stages of the hair follicle cycle in Jiangnan cashmere goats. Based on the previously obtained mRNA data, the target genes of DE miRNA were predicted, and 1,472 negative regulatory relationships between DE miRNAs and target genes were obtained. Notably, the expression of chi-miR-877-3p was down-regulated during the telogen (Tn) phase compared to the anagen (An) and catagen (Cn) phases, while the IGFBP5 gene exhibited up-regulation. Further validation experiments confirmed that overexpression of chi-miR-877-3p in dermal papilla cells suppressed IGFBP5 gene expression and facilitated cell proliferation. The results of this study provide novel insights for analyzing the hair follicle cycle.

Investigating the morphology and genetics of scalp and facial hair characteristics for phenotype prediction

Microscopic traits and ultrastructure of hair such as cross-sectional shape, pigmentation, curvature, and internal structure help determine the level of variations between and across human populations. Apart from cosmetics and anthropological applications, such as determining species, somatic origin (body area), and biogeographic ancestry, the evidential value of hair has increased with rapid progression in the area of forensic DNA phenotyping (FDP). Individuals differ in the features of their scalp hair (greying, shape, colour, balding, thickness, and density) and facial hair (eyebrow thickness, monobrow, and beard thickness) features. Scalp and facial hair characteristics are genetically controlled and lead to visible inter-individual variations within and among populations of various ethnic origins. Hence, these characteristics can be exploited and made more inclusive in FDP, thereby leading to more comprehensive, accurate, and robust prediction models for forensic purposes. The present article focuses on understanding the genetics of scalp and facial hair characteristics with the goal to develop a more inclusive approach to better understand hair biology by integrating hair microscopy with genetics for genotype-phenotype correlation research.

Comparative Analysis of mRNA and miRNA Expression between Dermal Papilla Cells and Hair Matrix Cells of Hair Follicles in Yak

The interaction between the dermal papilla cells (DPCs) and epidermal hair matrix cells (HMCs) of hair follicles (HFs) is crucial for the growth and development of HFs, but the molecular mechanism is complex and remains unclear. MicroRNAs (miRNAs) are the key signaling molecules for cellular communication. In this study, the DPCs and HMCs of yak were isolated and cultured, and the differentially expressed mRNA and miRNA were characterized to analyze the molecular basis of the interaction between DPCs and HMCs during hair follicle (HF) development in yak. The mRNA differential expression and functional enrichment analysis revealed that there were significant differences between DPCs and HMCs, and they showed the molecular functional characteristics of dermal cells and epidermal cells, respectively. Multiple KEGG pathways related to HF development were enriched in the highly expressed genes in DPCs, while the pathways associated with microbiota and immunity were significantly enriched in the highly expressed genes in HMCs. By combining analysis with our previous 10× genomics single-cell transcriptome data, 39 marker genes of DPCs of yak were identified. A total of 123 relatively specifically expressed miRNAs were screened; among these, the miRNAs associated with HF development such as miR-143, miR-214, miR-125b, miR-31, and miR-200 were presented. In conclusion, the large changes in yak DPCs and HMCs for both mRNA and miRNA expression were revealed, and numerous specifically expressed mRNAs and miRNAs in DPCs or HMCs were identified, which may contribute to the interaction and cellular communication between DPCs and HMCs during HF development in yak.

Cost-effectively dissecting the genetic architecture of complex wool traits in rabbits by low-coverage sequencing

Background

Rabbit wool traits are important in fiber production and for model organism research on hair growth, but their genetic architecture remains obscure. In this study, we focused on wool characteristics in Angora rabbits, a breed well-known for the quality of its wool. Considering the cost to generate population-scale sequence data and the biased detection of variants using chip data, developing an effective genotyping strategy using low-coverage whole-genome sequencing (LCS) data is necessary to conduct genetic analyses.

Results

Different genotype imputation strategies (BaseVar + STITCH, Bcftools + Beagle4, and GATK + Beagle5), sequencing coverages (0.1X, 0.5X, 1.0X, 1.5X, and 2.0X), and sample sizes (100, 200, 300, 400, 500, and 600) were compared. Our results showed that using BaseVar + STITCH at a sequencing depth of 1.0X with a sample size larger than 300 resulted in the highest genotyping accuracy, with a genotype concordance higher than 98.8% and genotype accuracy higher than 0.97. We performed multivariate genome-wide association studies (GWAS), followed by conditional GWAS and estimation of the confidence intervals of quantitative trait loci (QTL) to investigate the genetic architecture of wool traits. Six QTL were detected, which explained 0.4 to 7.5% of the phenotypic variation. Gene-level mapping identified the fibroblast growth factor 10 (FGF10) gene as associated with fiber growth and diameter, which agrees with previous results from functional data analyses on the FGF gene family in other species, and is relevant for wool rabbit breeding.

Conclusions

We suggest that LCS followed by imputation can be a cost-effective alternative to array and high-depth sequencing for assessing common variants. GWAS combined with LCS can identify new QTL and candidate genes that are associated with quantitative traits. This study provides a cost-effective and powerful method for investigating the genetic architecture of complex traits, which will be useful for genomic breeding applications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12711-022-00766-y.

An integrative analysis of the lncRNA-miRNA-mRNA competitive endogenous RNA network reveals potential mechanisms in the murine hair follicle cycle

Alopecia is a common progressive disorder associated with abnormalities of the hair follicle cycle. Hair follicles undergo cyclic phases of hair growth (anagen), regression (catagen), and rest (telogen), which are precisely regulated by various mechanisms. However, the specific mechanism associated with hair follicle cycling, which includes noncoding RNAs and regulation of competitive endogenous RNA (ceRNA) network, is still unclear. We obtained data from publicly available databases and performed real-time quantitative polymerase chain reaction validations. These analyses revealed an increase in the expression of miRNAs and a decrease in the expression of target mRNAs and lncRNAs from the anagen to telogen phase of the murine hair follicle cycle. Subsequently, we constructed the ceRNA networks and investigated their functions using enrichment analysis. Furthermore, the androgenetic alopecia (AGA) microarray data analysis revealed that several novel alopecia-related genes were identified in the ceRNA networks. Lastly, GSPT1 expression was detected using immunohistochemistry. Our analysis revealed 11 miRNAs (miR-148a-3p, miR-146a-5p, miR-200a-3p, miR-30e-5p, miR-30a-5p, miR-27a-3p, miR-143-3p, miR-27b-3p, miR-126a-3p, miR-378a-3p, and miR-22-3p), 9 target mRNAs (Atp6v1a, Cdkn1a, Gadd45a, Gspt1, Mafb, Mitf, Notch1, Plk2, and Slc7a5), and 2 target lncRNAs (Neat1 and Tug1) were differentially expressed in hair follicle cycling. The ceRNA networks were made of 12 interactive miRNA-mRNA pairs and 13 miRNA-lncRNA pairs. The functional enrichment analysis revealed the enrichment of hair growth–related signaling pathways. Additionally, GSPT1 was downregulated in androgenetic alopecia patients, possibly associated with alopecia progression. The ceRNA network identified by our analysis could be involved in regulating the hair follicle cycle.

Integrated analysis of miRNAs and mRNA profiling reveals the potential roles of miRNAs in sheep hair follicle development

BACKGROUND

Merino sheep exhibit high wool production and excellent wool quality. The fleece of Merino sheep is predominantly composed of wool fibers grown from hair follicles (HFs). The HF is a complex biological system involved in a dynamic process governed by gene regulation, and gene expression is regulated by microRNAs (miRNAs). miRNA inhibits posttranscriptional gene expression by specifically binding to target messenger RNA (mRNA) and plays an important role in regulating gene expression, the cell cycle and biological development sequences. The purpose of this study was to examine mRNA and miRNA binding to identify key miRNAs and target genes related to HF development. This will provide new and important insights into fundamental mechanisms that regulate cellular activity and cell fate decisions within and outside of the skin.

RESULTS

We analyzed miRNA data in skin tissues collected from 18 Merino sheep on four embryonic days (E65, E85, E105 and E135) and two postnatal days (D7 and D30) and identified 87 differentially expressed miRNAs (DE-miRNAs). These six stages were further divided into two longer developmental stages based on heatmap cluster analysis, and the results showed that DE-mRNAs in Stage A were closely related to HF morphogenesis. A coanalysis of Stage A DE-mRNAs and DE-miRNAs revealed that 9 DE-miRNAs and 17 DE-mRNAs presented targeting relationships in Stage A. We found that miR-23b and miR-133 could target and regulate ACVR1B and WNT10A. In dermal fibroblasts, the overexpression of miR-133 significantly reduced the mRNA and protein expression levels of ACVR1B. The overexpression of miR-23b significantly reduced the mRNA and protein expression levels of WNT10A.

CONCLUSION

This study provides a new reference for understanding the molecular basis of HF development and lays a foundation for further improving sheep HF breeding. miRNAs and target genes related to hair follicular development were found, which provided a theoretical basis for molecular breeding for the culture of fine-wool sheep.

Understanding Mammalian Hair Follicle Ecosystems by Single-Cell RNA Sequencing

Simple Summary

Single-cell sequencing technology can reflect cell population heterogeneity at the single-cell level, leading to a better understanding of the role of individual cells in the microenvironment. Over the past few years, single-cell sequencing technology has not only made more new discoveries in the study of cellular heterogeneity of other rare cells such as stem cells, but has also become the most powerful research method for embryonic development, organ differentiation, cancer occurrence, and cell mapping. In this review, we outline the use of scRNA-seq in hair follicles. In particular, by focusing on landmark studies and the recent discovery of novel subpopulations of hair follicles, we summarize the phenotypic diversity of hair follicle cells and their links to hair follicle morphogenesis. Enhancing our understanding of the progress of hair follicle research will help to elucidate the regulatory mechanisms that determine the fate of different types of cells in the hair follicle, thereby guiding hair loss treatment and hair-producing economic animal breeding research.

Abstract

Single-cell sequencing technology can fully reflect the heterogeneity of cell populations at the single cell level, making it possible for us to re-recognize various tissues and organs. At present, the sequencing study of hair follicles is transiting from the traditional ordinary transcriptome level to the single cell level, which will provide diverse insights into the function of hair follicle cells. This review focuses on research advances in the hair follicle microenvironment obtained from scRNA-seq studies of major cell types in hair follicle development, with a special emphasis on the discovery of new subpopulations of hair follicles by single-cell techniques. We also discuss the problems and current solutions in scRNA-seq observation and look forward to its prospects.

Lef1 and Dlx3 May Facilitate the Maturation of Secondary Hair Follicles in the Skin of Gansu Alpine Merino

Lymphatic enhancer factor 1 (Lef1) and distal-less homeobox 3 (Dlx3) are the transcription factors involved in regulating hair follicle development in mice, goats, and other animals. Their deletion can lead to hair follicle deficiency. In this study, hematoxylin−eosin staining (HE), real-time quantitative PCR (RT-qPCR), immunohistochemistry, and immunofluorescence were used to analyze the expression, location, and biological functions of Lef1 and Dlx3 in the lateral skin of Gansu Alpine Merino aged 1, 30, 60, and 90 days. The results revealed that the number of hair follicles decreased with age and was significantly higher at 1 day than in the other three age groups (p < 0.05). The mRNA levels of Lef1 and Dlx3 in the skin of 30-day old Gansu Alpine Merino were significantly higher than those in the other three age groups (p < 0.05). Protein expression of Lef1 and Dlx3 was lowest at 1 day (p < 0.05) and peaked at 60 days. Lef1 and Dlx3 exhibited a high density and strong positive expression in the dermal papillae; additionally, Dlx3 exhibited a high density and strong positive expression in the inner and outer root sheaths. Collectively, Lef1 and Dlx3 may facilitate the maturation of secondary hair follicles, which is mainly achieved through the dermal papillae and inner and outer root sheaths.

Dysregulated behaviour of hair follicle stem cells triggers alopecia and provides potential therapeutic targets

Due to a steady increase in the number of individuals suffering from alopecia, this condition has recently received increasing attention. Alopecia can be caused by various pathological, environmental or psychological factors, eventually resulting in abnormalities in hair follicle (HF) structures or HF regeneration disorders, especially dysregulated hair follicle stem cell (HFSC) behaviour. HFSC behaviour includes activation, proliferation and differentiation. Appropriate HFSC behaviour sustains a persistent hair cycle (HC). HFSC behaviour is mainly influenced by HFSC metabolism, ageing, and the microenvironment. In this review, we summarize recent findings on how HFSC metabolism, ageing and the microenvironment give rise to hair growth disorders, as well as related genes and signalling pathways. Recent research on the application of stem cell-based hair tissue engineering and regenerative medicine to treat alopecia is also summarized. Determining how dysregulated HFSC behaviour underlies alopecia would be helpful in identifying potential therapeutic targets.

miR-129-5p Participates in Hair Follicle Growth by Targeting HOXC13 in Rabbit

Mammalian hair formation is critically determined by the growth of hair follicles (HF). MiRNAs are crucial in the periodic development of hair follicles; they maintain epidermal homeostasis by targeting genes and influencing the activity of signaling pathways and related regulators. Our study discovered miR-129-5p to be overexpressed in the skin of Angora rabbits during catagen, and was negatively correlated with HOXC13 expression (Pearson’s R = −0.313, p < 0.05). The dual-Luciferase reporter gene detection system and Western blotting confirmed that miR-129-5p targeted HOXC13. In addition, miR-129-5p overexpression was found to significantly inhibit the expression of hair follicle development-related genes (HFDRGs), such as BCL2, WNT2, CCND1, and LEF1 (p < 0.01), and promoted the expression of SFRP2, TGF-β1, and FGF2 (p < 0.01), which was the same as the knockdown of HOXC13. In contrast, the knockout of miR-129-5p was the opposite, and it demonstrated similar results to the overexpression of HOXC13. CCK8 and flow cytometry demonstrated that miR-129-5p mimics significantly promoted the apoptosis of dermal papilla cells (DPCs) and inhibited proliferation (p < 0.01), while the inhibitor was found to reduce the apoptosis of DPCs and promote proliferation (p < 0.01). These results showed that miR-129-5p can participate in the periodic development of HF by targeting HOXC13, and it can induce apoptosis and inhibit proliferation of DPCs. These results will help to understand the role and mechanism of miR-129-5p in the periodic development of HF, and will provide support for subsequent studies, not only providing a theoretical basis for genetically improving the quality of hair in animals in the future, but also a new theory and method for diagnosing and treating hair loss in humans.

MiR-149-5p promotes β-catenin-induced goat hair follicle stem cell differentiation

The Yangtze River Delta white goat is a unique goat species that can produce superior-quality brush hair. The formation of superior-quality brush hair cannot occur without goat hair follicle stem cell differentiation. However, knowledge regarding the regulatory role of miR-149-5p in hair follicle stem cell differentiation is limited. Here, we found that miR-149-5p is widely expressed in the tissues of Yangtze River Delta white goats, but its expression in the skin tissue of superior-quality brush hair goats is high compared to normal- quality goats. The functional studies showed that miR-149-5p overexpression markedly facilitated hair follicle stem cell differentiation, whereas inhibiting miR-149-5p inhibited hair follicle stem cell differentiation. These results more clearly elucidate the regulatory role of miR-149-5p in hair follicle stem cell growth.

Integrated Hair Follicle Profiles of microRNAs and mRNAs to Reveal the Pattern Formation of Hu Sheep Lambskin

Hair follicle development is closely associated with wool curvature. Current studies reveal the crucial role of microRNAs (miRNAs) in hair follicle growth and development. However, few studies are known regarding their role in wool curvature. To reveal the potential roles of miRNAs in Hu sheep lambskin with different patterns, a total of 37 differentially expressed (DE) miRNAs were identified in hair follicles between small waves (SM) and straight wool (ST) groups using RNA-seq. Through functional enrichment and miRNA-mRNA co-expression analysis, some key miRNAs (oar-miR-143, oar-miR-200b, oar-miR-10a, oar-miR-181a, oar-miR-10b, oar-miR-125b, etc.) and miRNA-mRNA pairs (miR-125b target CD34, miR-181a target FGF12, LMO3, miR-200b target ZNF536, etc.) were identified. Though direct or indirect ways affecting hair follicle development, these miRNAs and mRNAs may have possible effects on wool curvature, and this study thus provides valuable insight on potential pattern formation.

miR-1 Regulates Differentiation and Proliferation of Goat Hair Follicle Stem Cells by Targeting IGF1R and LEF1 Genes

Hair follicle stem cells (HFSCs) play a significant role in hair development. miR-1 has been reported as an important regulatory factor that affects hair follicle growth and development, but its regulatory mechanism on HFSC development remains unknown. In this study, the molecular mechanism of miR-1 in regulating HFSC proliferation and differentiation was investigated. High-throughput RNA-seq and integrated analysis were performed to identify differentially transcribed mRNAs and microRNAs (miRNAs) in HFSCs co-cultured with dermal papilla cells (named dHFSCs) and control HFSCs. We then determined the molecular function of miR-1 in HFSCs. Compared with HFSCs, 13 differentially transcribed miRNAs were identified in dHFSCs. The in vitro results indicated that the overtranscription of miR-1 inhibited HFSC proliferation, but enhanced HFSC differentiation by targeting IGF1R and LEF1 genes. This study provides new insights into the molecular mechanisms of HFSC development. Approval ID (2014ZX08008-002).

Recreation of a hair follicle regenerative microenvironment: Successes and pitfalls

The hair follicle (HF) is an exquisite skin appendage endowed with cyclical regenerative capacity; however, de novo follicle formation does not naturally occur. Consequently, patients suffering from extensive skin damage or hair loss are deprived of the HF critical physiological and/or aesthetic functions, severally compromising skin function and the individual's psychosocial well-being. Translation of regenerative strategies has been prevented by the loss of trichogenic capacity that relevant cell populations undergo in culture and by the lack of suitable human-based in vitro testing platforms. Here, we provide a comprehensive overview of the major difficulties associated with HF regeneration and the approaches used to overcome these drawbacks. We describe key cellular requirements and discuss the importance of the HF extracellular matrix and associated signaling for HF regeneration. Finally, we summarize the strategies proposed so far to bioengineer human HF or hair-bearing skin models and disclose future trends for the field.

miR-143 Targeting CUX1 to Regulate Proliferation of Dermal Papilla Cells in Hu Sheep

Wool curvature is the determining factor for lambskin quality of Hu lambs. However, the molecular mechanism of wool curvature formation is not yet known. miRNA has been proved to play an important role in hair follicle development, and we have discovered a differentially expressed miRNA, miR-143, in hair follicles of different curl levels. In this study, we first examined the effects of miR-143 on the proliferation and cell cycle of dermal papilla cells using CCK8, EdU and flow cytometry and showed that miR-143 inhibited the proliferation of dermal papilla cells and slowed down the cell cycle. Bioinformatics analysis was performed to predict the target genes KRT71 and CUX1 of miR-143, and both two genes were expressed at significantly higher levels in small waves than in straight lambskin wool (p < 0.05) as detected by qPCR and Western blot (WB). Then, the target relationships between miR-143 and KRT71 and CUX1 were verified through the dual-luciferase assay in 293T cells. Finally, after overexpression and suppression of miR-143 in dermal papilla cells, the expression trend of CUX1 was contrary to that of miR-143. Meanwhile, KRT71 was not detected because KRT71 was not expressed in dermal papilla cells. Therefore, we speculated that miR-143 can target CUX1 to inhibit the proliferation of dermal papilla cells, while miR-143 can target KRT71 to regulate the growth and development of hair follicles, so as to affect the development of hair follicles and ultimately affect the formation of wool curvature.

Overexpression of miR-122 promotes apoptosis of dermal papilla cells by directly targeting IGF1R in androgenetic alopecia

Androgenetic alopecia (AGA) is the most common pattern of hair loss resulting from the effects of androgen on hair follicle. MicroRNAs (miRs) serve imperative roles in the regulation of many biological processes of hair follicle. However, the exact molecular mechanism of AGA remains to be elucidated. In the present study, we found miR-122, which is mainly recognized as a tumor suppressor, was highly overexpressed in the bulb of balding HFs in comparison with non-balding ones in AGA. Moreover, miR-122 induces apoptosis of human dermal papilla cells (hDPCs) with miR-122 mimics in vitro, and the expression of insulin-like growth factor 1 receptor (IGF1R) in hDPCs was reduced following upregulation of miR-122. Mechanistically, dual luciferase reporter assay confirmed that miR-122 directly targeted the 3'-untranslated region of IGF1R.These findings suggested that upregulation of miR-122 induces apoptosis, potentially via the repression of IGF1R in hDPCs of AGA, providing a novel insight into the potential pathological mechanism of miR-122 in AGA DPCs. This article is protected by copyright. All rights reserved.

Perspectives on miRNAs Targeting DKK1 for Developing Hair Regeneration Therapy

Androgenetic alopecia (AGA) remains an unsolved problem for the well-being of humankind, although multiple important involvements in hair growth have been discovered. Up until now, there is no ideal therapy in clinical practice in terms of efficacy and safety. Ultimately, there is a strong need for developing a feasible remedy for preventing and treating AGA. The Wnt/β-catenin signaling pathway is critical in hair restoration. Thus, AGA treatment via modulating this pathway is rational, although challenging. Dickkopf-related protein 1 (DKK1) is distinctly identified as an inhibitor of canonical Wnt/β-catenin signaling. Thus, in order to stimulate the Wnt/β-catenin signaling pathway, inhibition of DKK1 is greatly demanding. Studying DKK1-targeting microRNAs (miRNAs) involved in the Wnt/β-catenin signaling pathway may lay the groundwork for the promotion of hair growth. Bearing in mind that DKK1 inhibition in the balding scalp of AGA certainly makes sense, this review sheds light on the perspectives of miRNA-mediated hair growth for treating AGA via regulating DKK1 and, eventually, modulating Wnt/β-catenin signaling. Consequently, certain miRNAs regulating the Wnt/β-catenin signaling pathway via DKK1 inhibition might represent attractive candidates for further studies focusing on promoting hair growth and AGA therapy.

The Roles of Non-coding RNA in the Development and Regeneration of Hair Follicles: Current Status and Further Perspectives

Alopecia is a common problem that affects almost every age group and is considered to be an issue for cosmetic or psychiatric reasons. The loss of hair follicles (HFs) and hair caused by alopecia impairs self-esteem, thermoregulation, tactile sensation and protection from ultraviolet light. One strategy to solve this problem is HF regeneration. Many signalling pathways and molecules participate in the morphology and regeneration of HF, such as Wnt/β-catenin, Sonic hedgehog, bone morphogenetic protein and Notch. Non-coding RNAs (ncRNAs), especially microRNAs and long ncRNAs, have significant modulatory roles in HF development and regeneration via regulation of these signalling pathways. This review provides a comprehensive overview of the status and future prospects of ncRNAs in HF regeneration and could prompt novel ncRNA-based therapeutic strategies.

Changthangi Pashmina Goat Genome: Sequencing, Assembly, and Annotation

Pashmina goats produce the world's finest and the most costly animal fiber (Pashmina) with an average fineness of 11-13 microns and have more evolved mechanisms than any known goat breed around the globe. Despite the repute of Pashmina goat for producing the finest and most sought-after animal fiber, meager information is available in the public domain about Pashmina genomics and transcriptomics. Here we present a 2.94 GB genome sequence from a male Changthangi white Pashmina goat. We generated 294.8 GB (>100X coverage) of the whole-genome sequence using the Illumina HiSeq 2500 sequencer. All cleaned reads were mapped to the goat reference genome (2,922,813,246 bp) which covers 97.84% of the genome. The Unaligned reads were used for de novo assembly resulting in a total of 882 MB non-reference contigs. De novo assembly analysis presented in this study provides important insight into the adaptation of Pashmina goats to cold stress and helps enhance our understanding of this complex phenomenon. A comparison of the Pashmina goat genome with a wild goat genome revealed a total of 2,823 high impact single nucleotide variations and small insertions and deletions, which may be associated with the evolution of Pashmina goats. The Pashmina goat genome sequence provided in this study may improve our understanding of complex traits found in Pashmina goats, such as annual fiber cycling, defense mechanism against hypoxic, survival secret in extremely cold conditions, and adaptation to a sparse diet. In addition, the genes identified from de novo assembly could be utilized in differentiating Pashmina fiber from other fibers to avoid falsification at marketing practices.

Chi-miR-370-3p regulates hair follicle morphogenesis of Inner Mongolian cashmere goats

MicroRNAs (miRNAs), a class of 22 nucleotide (nt) noncoding RNAs, negatively regulate mRNA posttranscriptional modification in various biological processes. Morphogenesis of skin hair follicles in cashmere goats is a dynamic process involving many key signaling molecules, but the associated cellular biological mechanisms induced by these key signaling molecules have not been reported. In this study, differential expression, bioinformatics, and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed on miRNA expression profiles of Inner Mongolian cashmere goats at 45, 55, and 65 days during the fetal period, and chi-miR-370-3p was identified and investigated further. Real-time fluorescence quantification (qRT-PCR), dual luciferase reporting, and Western blotting results showed that transforming growth factor beta receptor 2 (TGF-βR2) and fibroblast growth factor receptor 2 (FGFR2) were the target genes of chi-miR-370-3p. Chi-miR-370-3p also regulated the expression of TGF-βR2 and FGFR2 at mRNA and protein levels in epithelial cells and dermal fibroblasts. DNA staining, Cell Counting Kit-8, and fluorescein-labelled Annexin V results showed that chi-miR-370-3p inhibited the proliferation of epithelial cells and fibroblasts but had no effect on apoptosis. Cell scratch test results showed that chi-miR-370-3p promoted the migration of epithelial cells and fibroblasts. Chi-miR-370-3p inhibits the proliferation of epithelial cells and fibroblasts by targeting TGF-βR2 and FGFR2, thereby improving cell migration ability and ultimately regulating the fate of epithelial cells and dermal fibroblasts to develop the placode and dermal condensate, inducing hair follicle morphogenesis.

Silencing MAP3K1 expression inhibits the proliferation of goat hair follicle stem cells

The Yangtze River Delta White Goat is the only goat breed in the world that can produce superior-quality brush hair. Previous studies have shown that some genes are expressed differentially in the skin tissues between the goats produced superior-quality and normal-quality brush hair. Studies also have shown that different gene play varied roles in regulating the proliferation and apoptosis of hair follicle stem cells. However, the biological function of MAP3K1 (mitogen-activated protein kinase kinase kinase 1) gene in hair follicle stem cells is not fully understood. This study aims to investigate the role of MAP3K1 knockdown during the proliferation and apoptosis of hair follicle stem cells. RT-qPCR and Western blot were used to detect mRNA gene and protein expression level, CCK-8 and EdU assays were used to detect cell proliferation, and cell cycle and apoptosis were detected by flow cytometry. The results showed that the MAP3K1 expression level was significantly higher in the skin tissue of produced superior-quality brush hair than that in produced normal-quality brush hair. Moreover, functional studies indicated that si-MAP3K1 significantly inhibits the proliferation of hair follicle stem cells that came from a superior goat and promotes its apoptosis. Based on aforementioned assays, we speculated that MAP3K1 might play a regulatory effect in superior-quality brush hair traits.

Detection of MicroRNAs by In Situ Hybridization in Skin

MicroRNAs (miRNAs) are a family of small noncoding RNAs (~19-24 nt) playing a key role in the execution of gene expression programs in various cells and tissues. Many technical challenges have been encountered when investigating miRNAs, in particular, determining the spatiotemporal expression pattern of miRNAs in cells and tissues. We describe here a well-established in situ hybridization protocol for the detection and analysis of spatiotemporal expression patterns of miRNAs in skin and its appendages such as the hair follicle in both frozen and paraffin-embedded tissue sections. We describe in detail the different steps that are associated with utilizing in situ hybridization procedure on either frozen or paraffin-embedded tissues for miRNAs localization. Postfixation, tissues are hybridized with LNA double labeled probes with digoxygenin. Detection of hybridized probes is performed by using an alkaline phosphatase coupled antibody against digoxygenin. The final step involves the use of substrates to develop the color of alkaline phosphatase-LNA-probe structure leading to identification of the spatiotemporal location of target miRNAs in target tissue and cells. We also discuss two options for substrate color development in these procedures: (1) NBT/BCIP and (2) BM Purple. This method is a simple and convenient way of determining the spatiotemporal expression pattern of miRNAs, which has been a challenge since their discovery, due to their relatively small size. Knowledge gained from in situ hybridization is crucial for better understanding of the roles of individual miRNA(s) during distinct stages of development in various cells and tissues. These protocols will be beneficial to the wider scientific community.

Epigenetic Regulation of Epidermal Differentiation

The epidermis is the outer part of the skin that protects the organism from dehydration and shields from external insults. Epidermal cells, called keratinocytes, undergo a series of morphological and metabolic changes that allow them to establish the biochemical and structural elements of an effective epidermal barrier. This process, known as epidermal differentiation, is critical for the maintenance of the epidermis under physiological conditions and also under stress or in various skin pathologies. Epidermal differentiation relies on a highly coordinated program of gene expression. Epigenetic mechanisms, which commonly include DNA methylation, covalent histone modifications, and microRNA (miRNA) activity, modulate various stages of gene expression by altering chromatin accessibility and mRNA stability. Their involvement in epidermal differentiation is a matter of intensive studies, and the results obtained thus far show a complex network of epigenetic factors, acting together with transcriptional regulators, to maintain epidermal homeostasis and counteract adverse effects of environmental stressors.

miR-31-5p promotes proliferation and inhibits apoptosis of goat hair follicle stem cells by targeting RASA1/MAP3K1 pathway

The Yangtze River Delta white goat is a sole goat species that can naturally produce superior-quality brush hair. It's worth to mention that study the developmental mechanism of goat hair follicle stem cells is vital for future breed preservation and molecular breeding. In this study, we successfully isolated hair follicle stem cells from the skin tissue of fetal sheep neck spine, and harvested superior-quality and normal-quality brush hair goat tissue. The expression of miR-31-5p in goat hair follicle stem cells was verified by qPCR and Western blot. The effects of overexpression or inhibition of miR-31-5p on the proliferation and apoptosis of hair follicle stem cells were detected by EdU, CCK-8, flow cytometry, etc. miR-31-5p can significantly improve cell proliferation and inhibit cell apoptosis by targeting RASA1 and upregulating MAP3K1 level, whereas miR-31-5p knockdown led to an opposite effect. These results reveal a miR-31-5p-associated regulatory network between miR-31-5p and RASA1/MAP3K1 during the progression of superiorquality brush hair traits.

miR-140-5p in Small Extracellular Vesicles From Human Papilla Cells Stimulates Hair Growth by Promoting Proliferation of Outer Root Sheath and Hair Matrix Cells

The application of dermal papilla cells to hair follicle (HF) regeneration has attracted a great deal of attention. However, cultured dermal papilla cells (DPCs) tend to lose their capacity to induce hair growth during passage, restricting their usefulness. Accumulating evidence indicates that DPCs regulate HF growth mainly through their unique paracrine properties, raising the possibility of therapies based on extracellular vesicles (EVs). In this study, we explored the effects of EVs from high- and low-passage human scalp follicle dermal papilla cells (DP-EVs) on activation of hair growth, and investigated the underlying mechanism. DP-EVs were isolated by ultracentrifugation and cultured with human scalp follicles, hair matrix cells (MxCs), and outer root sheath cells (ORSCs), and we found low-passage DP-EVs accelerated HF elongation and cell proliferation activation. High-throughput miRNA sequencing and bioinformatics analysis identified 100 miRNAs that were differentially expressed between low- (P3) and high- (P8) passage DP-EVs. GO and KEGG pathway analysis of 1803 overlapping target genes revealed significant enrichment in the BMP/TGF-β signaling pathways. BMP2 was identified as a hub of the overlapping genes. miR-140-5p, which was highly enriched in low-passage DP-EVs, was identified as a potential regulator of BMP2. Direct repression of BMP2 by miR-140-5p was confirmed by dual-luciferase reporter assay. Moreover, overexpression and inhibition of miR-140-5p in DP-EVs suppressed and increased expression of BMP signaling components, respectively, indicating that this miRNA plays a critical role in hair growth and cell proliferation. DP-EVs transport miR-140-5p from DPCs to epithelial cells, where it downregulates BMP2. Therefore, DPC-derived vesicular miR-140-5p represents a therapeutic target for alopecia.

An Intrinsic Oscillation of Gene Networks Inside Hair Follicle Stem Cells: An Additional Layer That Can Modulate Hair Stem Cell Activities

This article explores and summarizes recent progress in and the characterization of main players in the regulation and cyclic regeneration of hair follicles. The review discusses current views and discoveries on the molecular mechanisms that allow hair follicle stem cells (hfSCs) to synergistically integrate homeostasis during quiescence and activation. Discussion elaborates on a model that shows how different populations of skin stem cells coalesce intrinsic and extrinsic mechanisms, resulting in the maintenance of stemness and hair regenerative potential during an organism’s lifespan. Primarily, we focus on the question of how the intrinsic oscillation of gene networks in hfSCs sense and respond to the surrounding niche environment. The review also investigates the existence of a cell-autonomous mechanism and the reciprocal interactions between molecular signaling axes in hfSCs and niche components, which demonstrates its critical driving force in either the activation of whole mini-organ regeneration or quiescent homeostasis maintenance. These exciting novel discoveries in skin stem cells and the surrounding niche components propose a model of the intrinsic stem cell oscillator which is potentially instructive for translational regenerative medicine. Further studies, deciphering of the distribution of molecular signals coupled with the nature of their oscillation within the stem cells and niche environments, may impact the speed and efficiency of various approaches that could stimulate the development of self-renewal and cell-based therapies for hair follicle stem cell regeneration.

miRNA microarray profiling in patients with androgenic alopecia and the effects of miR-133b on hair growth

OBJECTIVE

Androgenetic alopecia (AGA), a common alopecia, is often accompanied by abnormal expression of multiple miRNAs. This study aims to investigate abnormally expressed miRNAs in patients with AGA and their specific molecular mechanism.

METHODS

miRNA microarray profiling and qRT-PCR validation were used to screen and verify abnormally expressed miRNAs in patients with AGA. Human hair follicles (HFs) were treated with different concentrations of dihydrotestosterone (DHT, 10^-5, 10^-6, 10^-7 and 10^-8 mol/L) for 10 days. The effects of DHT on HF growth, proliferation, and miRNA expression in cultured HFs were investigated using immunofluorescence staining and qRT-PCR. Moreover, human dermal papilla cells (HDPCs) were treated/transfected with a Wnt/β-catenin pathway activator and/or miR-133b mimic, and then the CCK-8 assay was used to evaluate HDPC proliferation. qRT-PCR and Western blotting were used to measure the expression of Versican, ALP and β-catenin RESULTS: miRNA microarray profiling identified 43 miRNAs that were significantly differentially expressed in AGA patients, and qRT-PCR verified that 8 miRNAs were significantly differentially expressed. The expression of miR-133b was abnormally high in AGA patients. DHT (10^-5 mol/L) inhibited human HF growth and upregulated miR-133b expression, and DHT (10^-7 mol/L) induced human HF growth and downregulated miR-133b expression. HDPC proliferation was inhibited, and the expression of β-catenin was downregulated in the miR-133b mimic-transfected group compared with the control group (P < 0.05). Wnt/β-catenin pathway activator treatment significantly promoted HDPC proliferation and upregulated the expression of β-catenin (P < 0.05). In addition, the proliferation of HDPCs was not significantly different between the group cotreated with a Wnt/β-catenin pathway activator and miR-133b mimic, and the control group (P > 0.05), but the expression of Versican and ALP was suppressed in the cotreatment group (P < 0.05) CONCLUSION: Our data indicated that patients with androgenic alopecia have specific miRNA expression profiles and that the abnormal expression of miR-133b may inactivate the Wnt/β-catenin pathway and ultimately regulate hair growth.

miR-149-5p Regulates Goat Hair Follicle Stem Cell Proliferation and Apoptosis by Targeting the CMTM3/AR Axis During Superior-Quality Brush Hair Formation

The Yangtze River Delta white goat is a unique goat species that can produce superior quality brush hair. CKLF-like MARVEL transmembrane domain-containing 3 (CMTM3), which influences the transcriptional activity of androgen receptor (AR), was identified as a candidate gene related to superior-quality brush hair formation. CMTM3 is generally expressed at low levels, but miR-149-5p is highly expressed in the skin tissues of these goats. The mechanism by which CMTM3 regulates the proliferation and apoptosis of goat hair follicle stem cells has not been elucidated. Here, RT-qPCR, western blotting, 5-ethynyl-2′-deoxyuridine (EdU), cell cycle, apoptosis, and dual-luciferase assays were used to investigate the role and regulatory mechanism of CMTM3 and miR-149-5p. Functional studies showed that CMTM3 overexpression inhibited proliferation and induced apoptosis in cultured hair follicle stem cells, whereas silencing CMTM3 markedly facilitated cell proliferation and deterred apoptosis in cultured hair follicle stem cells. Then, using bioinformatic predictions and the aforementioned assays, including dual-luciferase assays, RT-qPCR, and western blotting, we confirmed that miR-149-5p targets CMTM3 and preliminarily investigated the interaction between CMTM3 and AR in goat hair follicle stem cells. Furthermore, miR-149-5p overexpression significantly accelerated the proliferation and attenuated the apoptosis of hair follicle stem cells. Conversely, miR-149-5p inhibition suppressed the proliferation and induced the apoptosis of hair follicle stem cells. These results reveal a miR-149-5p-related regulatory framework for the miR-149-5p/CMTM3/AR axis during superior quality brush hair formation, in which CMTM3 plays a negative role.

Defining microRNA signatures of hair follicular stem and progenitor cells in healthy and androgenic alopecia patients

BACKGROUND

The exact pathogenic mechanism causes hair miniaturization during androgenic alopecia (AGA) has not been delineated. Recent evidence has shown a role for non-coding regulatory RNAs, such as microRNAs (miRNAs), in skin and hair disease. There is no reported information about the role of miRNAs in hair epithelial cells of AGA.

OBJECTIVES

To investigate the roles of miRNAs affecting AGA in normal and patient's epithelial hair cells.

METHODS

Normal follicular stem and progenitor cells, as well as follicular patient's stem cells, were sorted from hair follicles, and a miRNA q-PCR profiling to compare the expression of 748 miRNA (miRs) in sorted cells were performed. Further, we examined the putative functional implication of the most differentially regulated miRNA (miR-324-3p) in differentiation, proliferation and migration of cultured keratinocytes by qRT-PCR, immunofluorescence, and scratch assay. To explore the mechanisms underlying the effects of miR-324-3p, we used specific chemical inhibitors targeting pathways influenced by miR-324-3p.

RESULT

We provide a comprehensive assessment of the "miRNome" of normal and AGA follicular stem and progenitor cells. Differentially regulated miRNA signatures highlight several miRNA candidates including miRNA-324-3p as mis regulated in patient's stem cells. We find that miR-324-3p promotes differentiation and migration of cultured keratinocytes likely through the regulation of mitogen-activated protein kinase (MAPK) and transforming growth factor (TGF)-β signaling. Importantly, pharmacological inhibition of the TGF-β signaling pathway using Alk5i promotes hair shaft elongation in an organ-culture system.

CONCLUSION

Together, we offer a platform for understanding miRNA dynamic regulation in follicular stem and progenitor cells in baldness and highlight miR-324-3p as a promising target for its treatment.

DNMT1-mediated methylation inhibits microRNA-214-3p and promotes hair follicle stem cell differentiate into adipogenic lineages

Background

Dysfunction of the DNA methylation was associated with stem cell reprogramming. Moreover, DNA methyltransferase 1 (DNMT1) deficiency was involved in the differentiation of hair follicle stem cell (HFSc), but the molecular mechanisms remain unknown.

Methods

HFSc from human scalp tissues were isolated and cultured. The oil red O staining was used to observe the adipogenesis. The interaction relationship between microRNA (miR)-214-3p and mitogen-activated protein kinase 1 (MAPK1) was accessed by dual-luciferase reporter gene assay. The methylation level of miR-214-3p promoter was detected by methylation-specific PCR and the enrichment of DNMT1 in miR-214-3p promoter by chromatin immunoprecipitation assay. A mouse model of trauma was established to observe the skin regeneration at 0, 6, and 14 days.

Results

Expression of DNMT1 and MAPK1 was increased in the HFSc, while the expression of miR-214-3p was reduced. Moreover, DNMT1 inhibited the expression of miR-214-3p by promoting the promoter methylation of miR-214-3p. Overexpression of DNMT1 could reduce the expression of miR-214-3p, but increase the expression of MAPK1 and the extent of extracellular signal regulated kinase (ERK)1/2 phosphorylation, leading to enhanced adipogenic differentiation. Importantly, DNMT1 promoted skin regeneration in vivo. Conversely, overexpression of miR-214-3p could reverse the effects of DNMT1 on adipogenesis of HFSc.

Conclusion

DNMT1 promotes adipogenesis of HFSc by mediating miR-214-3p/MAPK1/p-ERK1/2 axis. This study may provide novel biomarkers for the potential application in stem cell therapy.

MicroRNA-31 regulates dental epithelial cell proliferation by targeting Satb2

MicroRNAs (miRNAs) exhibit strong potential clinical application owing to their extensive regulation and flexible delivery properties. MicroRNA-31 (miR-31) is an evolutionarily conserved miRNA expressed during tooth development, and it is highly expressed in mouse incisor epithelium. The specific role of miR-31 in odontogenesis has not been elucidated comprehensively, and the aim of the present study was to investigate its activity. Our results showed that miR-31 suppressed LS8 cell proliferation by inhibiting the cell cycle at the G1/S transition. Mutation of Special AT-rich sequence-binding protein 2 (SATB2) gene is responsible for human SATB2-associated syndrome (SAS), which is often accompanied by dental abnormities. Here, it was identified as a direct target of miR-31 in LS8 cells and a promoter of cell proliferation. The expression and distribution of SATB2 in mouse molars and incisors were explored using immunofluorescence, which showed strong signals in the nuclei of incisor epithelial cells and weak signals in the cytoplasm of molar epithelial cells. Moreover, rescue experiments demonstrated that Satb2 could mitigate the inhibitory effect of miR-31 on cell proliferation by promoting the expression of CDK4. Collectively, our results suggested that miR-31 regulates dental epithelial cell proliferation by targeting Satb2, highlighting the biological importance of miR-31 in odontogenesis.

Expression Profiling and Functional Characterization of miR-26a and miR-130a in Regulating Zhongwei Goat Hair Development via the TGF-β/SMAD Pathway

The Zhongwei goat is an important and unique goat breed indigenous to China. It has a natural hair curling phenotype at birth, but the degree of curling gradually decreases with growth. The molecular mechanism underlying the dynamic changes in the wool curvature in Zhongwei goats is poorly understood. MicroRNAs (miRNAs) play important roles in many biological processes, including hair growth and development. In this study, we selected skins from Zhongwei goats at different ages (45 and 108 days) that exhibited different levels of hair curvature and performed miRNA sequencing to explore the molecular mechanism of hair bending. In total, 28 significantly differentially expressed miRNAs (DE miRNAs) were identified in the three groups of samples between the two developmental stages. An analysis of the target genes of the above-mentioned DE miRNAs by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that the DE miRNAs were involved in signal pathways which were previously associated with hair bending and hair follicle development, such as the TGF-β/SMAD, PI3K-Akt, JAK-STAT, and MAPK pathways. A comprehensive analysis of the correlations between the miRNA-seq results and issued transcriptional findings indicated that SMAD1 was a target gene of miR-26a and SMAD5 was a target gene of miR-130a. Furthermore, goat dermal papilla cells were successfully isolated and purified to determine the role of miRNAs in follicle development in vitro. The study results demonstrated that miR-130a and miR-26a had significant effects on the proliferation of dermal papilla cells. In addition, the detection results of mRNA and protein levels indicate that the overexpression of miR-26a can promote the expression of related genes in the TGF-β/SMAD pathway, while miR-130a has the opposite substitution effect. The dual luciferase report test showed that miR-26a targeted the SMAD1 gene and reduced the expression of the SMAD1 protein in hair papillary cells. Our results identified DE microRNAs which perhaps change at the time of hair straightening in Zhongwei goats and explore the role of miR-26a and miR-130a in dermal papilla cells proliferation. The present study provided a theoretical basis to explore the mechanisms underlying the Zhongwei hair growth and curly phenotype.

Dicer- and Bulge Stem Cell-Dependent MicroRNAs During Induced Anagen Hair Follicle Development

MicroRNAs (miRNAs) are a major class of conserved non-coding RNAs that have a wide range of functions during development and disease. Biogenesis of canonical miRNAs depend on the cytoplasmic processing of pre-miRNAs to mature miRNAs by the Dicer endoribonuclease. Once mature miRNAs are generated, the miRNA-induced silencing complex (miRISC), or miRISC, incorporates one strand of miRNAs as a template for recognizing complementary target messenger RNAs (mRNAs) to dictate post-transcriptional gene expression. Besides regulating miRNA biogenesis, Dicer is also part of miRISC to assist in activation of the complex. Dicer associates with other regulatory miRISC co-factors such as trans-activation responsive RNA-binding protein 2 (Tarbp2) to regulate miRNA-based RNA interference. Although the functional role of miRNAs within epidermal keratinocytes has been extensively studied within embryonic mouse skin, its contribution to the normal function of hair follicle bulge stem cells (BSCs) during post-natal hair follicle development is unclear. With this question in mind, we sought to ascertain whether Dicer-Tarpb2 plays a functional role within BSCs during induced anagen development by utilizing conditional knockout mouse models. Our findings suggest that Dicer, but not Tarbp2, functions within BSCs to regulate induced anagen (growth phase) development of post-natal hair follicles. These findings strengthen our understanding of miRNA-dependency within hair follicle cells during induced anagen development.

The functions of ocu-miR-205 in regulating hair follicle development in Rex rabbits

BACKGROUND

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) 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.

RESULTS

The 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).

CONCLUSIONS

In 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.

The comprehensive detection of miRNA, lncRNA, and circRNA in regulation of mouse melanocyte and skin development

BACKGROUND

Pigmentation development, is a complex process regulated by many transcription factors during development. With the development of the RNA sequencing (RNA-seq), non-coding RNAs, such as miRNAs, lncRNAs, and circRNAs, are found to play an important role in the function detection of related regulation factors. In this study, we provided the expression profiles and development of ncRNAs related to melanocyte and skin development in mice with black coat color skin and mice with white coat color skin during embryonic day 15 (E15) and postnatal day 7 (P7). The expression profiles of different ncRNAs were detected via RNA-seq and also confirmed by the quantitative real-time PCR (qRT-PCR) method. GO and KEGG used to analyze the function the related target genes.

RESULTS

We identified an extensive catalogue of 206 and 183 differently expressed miRNAs, 600 and 800 differently expressed lncRNAs, and 50 and 54 differently expressed circRNAs, respectively. GO terms and pathway analysis showed the target genes of differentially expressed miRNA and lncRNA. The host genes of circRNA were mainly enriched in cellular process, single organism process. The target genes of miRNAs were mainly enriched in chromatin binding and calcium ion binding in the nucleus. The function of genes related to lncRNAs are post translation modification. The competing endogenous RNA (ceRNA) network of lncRNAs and circRNAs displays a complex interaction between ncRNA and mRNA related to skin development, such as Tcf4, Gnas, and Gpnms related to melanocyte development.

CONCLUSIONS

The ceRNA network of lncRNA and circRNA displays a complex interaction between ncRNA and mRNA related to skin development and melanocyte development. The embryonic and postnatal development of skin provide a reference for further studies on the development mechanisms of ncRNA during pigmentation.

Comprehensive analysis of circRNAs from cashmere goat skin by next generation RNA sequencing (RNA-seq)

Circular RNA (circRNA) is endogenous non-coding RNA (ncRNA) with a covalently closed circular structure. It is mainly generated through RNA alternative splicing or back-splicing. CircRNA is known in the majority of eukaryotes and very stable. However, knowledge of the circRNA involved in regulating cashmere fineness is limited. Skin samples were collected from Liaoning cashmere goats (LCG) and Inner Mongolia cashmere goats (MCG) during the anagen period. For differentially expressed circRNAs, RNA sequencing was performed, and the analysis led to an identification of 17 up-regulated circRNAs and 15 down-regulated circRNAs in LCG compared with MCG skin samples. In order to find the differentially expressed circRNAs in LCG, we carried out qPCRs on 10 candidate circRNAs in coarse type skin of LCG (CT-LCG) and fine type skin of LCG (FT-LCG). Four circRNAs: ciRNA128, circRNA6854, circRNA4154 and circRNA3620 were confirmed to be significantly differential expression in LCG. Also, a regulatory network of circRNAs-miRNAs was bioinformatically deduced and may help to understand molecular mechanisms of potential circRNA involvement in regulating cashmere fineness.

Anti-inflammatory and cell proliferative effect of the 1270 nm laser irradiation on the BALB/c nude mouse model involves activation of the cell antioxidant system

Recently, many interdisciplinary community researchers have focused their efforts on study of the low-level light irradiation effects (photobiomodulation, PBM) as a promising therapeutic technology. Among the priorities, a search of new wavelength ranges of laser radiation to enhance the laser prospects in treatment of autoimmune and cancer diseases commonly accompanied by disorders in the antioxidant system of the body. The laser wavelengths within 1265-1270 nm corresponds to the maximum oxygen absorption band. Therefore, PBM effects on a model organism within this spectrum range are of particular interest for preclinical research. Here, we report comprehensive biomolecular studies of the changes in the BALB/c nude mice skin after an exposure to the continuous laser radiation at the 1270 nm wavelength and energy densities of 0.12 and 1.2 J/cm2. Such regime induces both local and systemic PBM effects, presumably due to the short-term increase in ROS levels, which in turn activate the cell antioxidative system.

Exosomal Micro RNAs Derived from Dermal Papilla Cells Mediate Hair Follicle Stem Cell Proliferation and Differentiation

Recent studies have demonstrated that dermal papilla cell-derived exosomes (DPC-Exos) promote the anagen stage of hair follicle (HF) growth and delay the catagen stage. However, the roles of DPC-Exos in regulating hair follicle stem cell (HFSC) quiescence and activation remain unknown. Here, we found that HFSC differentiation was induced by co-culture with DPCs, and that DPC-Exos attached to the surface of HFSCs. Using micro RNA (miRNA) high-throughput sequencing, we identified 111 miRNAs that were significantly differentially expressed between DPC-Exos and DPCs, and the predicted target genes of the top 34 differentially expressed miRNAs indicated that DPC-Exos regulate HFSCs proliferation and differentiation via genes involved in cellular signal transduction, fatty acid expression regulation, and cellular communication. The overexpression of miR-22-5p indicated that it negatively regulates HFSC proliferation and LEF1 was revealed as the direct target gene of miR-22-5p. We therefore propose the miR-22-5p-LEF1 axis as a novel pathway regulating HFSC proliferation.

Systematic Analysis of Non-coding RNAs Involved in the Angora Rabbit (Oryctolagus cuniculus) Hair Follicle Cycle by RNA Sequencing

The hair follicle (HF) cycle is a complicated and dynamic process in mammals, associated with various signaling pathways and gene expression patterns. Non-coding RNAs (ncRNAs) are RNA molecules that are not translated into proteins but are involved in the regulation of various cellular and biological processes. This study explored the relationship between ncRNAs and the HF cycle by developing a synchronization model in Angora rabbits. Transcriptome analysis was performed to investigate ncRNAs and mRNAs associated with the various stages of the HF cycle. One hundred and eleven long non-coding RNAs (lncRNAs), 247 circular RNAs (circRNAs), 97 microRNAs (miRNAs), and 1,168 mRNAs were differentially expressed during the three HF growth stages. Quantitative real-time PCR was used to validate the ncRNA transcriptome analysis results. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses provided information on the possible roles of ncRNAs and mRNAs during the HF cycle. In addition, lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA ceRNA networks were constructed to investigate the underlying relationships between ncRNAs and mRNAs. LNC_002919 and novel_circ_0026326 were found to act as ceRNAs and participated in the regulation of the HF cycle as miR-320-3p sponges. This research comprehensively identified candidate regulatory ncRNAs during the HF cycle by transcriptome analysis, highlighting the possible association between ncRNAs and the regulation of hair growth. This study provides a basis for systematic further research and new insights on the regulation of the HF cycle.