The intragenic mRNA-microRNA regulatory network during telogen-anagen hair follicle transition in the cashmere goat

Deciphering the molecular drivers for cashmere/pashmina fiber production in goats: a comprehensive review

Cashmere, also known as pashmina, is derived from the secondary hair follicles of Cashmere/Changthangi goats. Renowned as the world's most luxurious natural fiber, it holds significant economic value in the textile industry. This comprehensive review enhances our understanding of the complex biological processes governing cashmere/pashmina fiber development and quality, enabling advancements in selective breeding and fiber enhancement strategies. The review specifically examines the molecular determinants influencing fiber development, with an emphasis on keratins (KRTs) and keratin-associated proteins (KRTAPs). It also explores the roles of key molecular pathways, including Wnt, Notch, BMP, NF-kappa B, VEGF, cAMP, PI3K-Akt, ECM, cell adhesion, Hedgehog, MAPK, Ras, JAK-STAT, TGF-β, mTOR, melanogenesis, FoxO, Hippo, and Rap1 signaling. Understanding these intricate molecular cascades provides valuable insights into the mechanisms orchestrating hair follicle growth, further advancing the biology of this coveted natural fiber. Expanding multi-omics approaches will enhance breeding precision and deepen our understanding of molecular pathways influencing cashmere production. Future research should address critical gaps, such as the impact of environmental factors, epigenetic modifications, and functional studies of genetic variants. Collaboration among breeders, researchers, and policymakers is essential for translating genomic advancements into practical applications. Such efforts can promote sustainable practices, conserve biodiversity, and ensure the long-term viability of high-quality cashmere production. Aligning genetic insights with conservation strategies will support the sustainable growth of the cashmere industry while preserving its economic and ecological value.

A comparative proteomic-based study identifies essential factors involved in hair follicle growth in inner Mongolia cashmere goats

Renowned for its invaluable undercoat, the cashmere goat is well known. The growth of cashmere fibre initiates when the relatively inactive telogen stage transitions to the anagen stage, which involves active proliferation. However, the molecular mechanisms responsible for this process are still unclear. Here, SWATH mass spectrometry (MS), a comparative proteomic analysis, was conducted to examine the proteomic alterations in Inner Mongolia cashmere goat skin samples at two different developmental stages (anagen and telogen). In total, 2414 proteins were detected, with 631 proteins showing differential regulation (503 upregulated proteins and 128 downregulated proteins). Bioinformatic analysis revealed that these proteins, which are differentially regulated, play crucial roles in the pathways associated with metabolism and fatty acids according to the GO and KEGG analyses. Furthermore, interactome analysis revealed that differentially regulated keratins have a crucial impact. The localization of KRT25, KRT71, and KRT82 using immunohistochemistry revealed that these proteins were expressed in the secondary hair follicles of cashmere goat skin. The keratin family plays an irreplaceable and important role in the process of hair follicle growth.

TMT-based quantitative proteomics reveals the genetic mechanisms of secondary hair follicle development in fine-wool sheep

The development of secondary hair follicles influences the quality of sheep wool. However, the mechanism by which proteins mediate the fetal development of secondary hair follicles remains unknown. In this study, the histomorphology of secondary hair follicles was analyzed over four stages of fetal development (75, 85, 95, and 105 gestational days). TMT-based quantitative proteomics was used to compare the differential protein profiles of skin tissues between consecutive developmental periods (75 versus 85, 85 versus 95, and 95 versus 105 gestational days). We found that the density of secondary hair follicles and the secondary hair follicles/primary hair follicles ratio increased from 85 to 105 gestational days. Bioinformatic analysis identified 238, 35, and 348 differentially expressed proteins in the respective comparison periods. Focal adhesion, ECM-receptor interaction, and the estrogen signaling pathway all played important roles in secondary hair follicle development. COL1A1, THBS3, ITGA6, COL6A1, and THBS4 were identified as potential candidate proteins in the initiation of secondary hair follicles. This study provides valuable proteomics data on secondary hair follicle development and thus has deepened our understanding of the molecular mechanisms underlying wool quality traits in fine-wool sheep.

Whole-transcriptome analysis reveals the profiles and roles of coding and non-coding RNAs during hair follicle cycling in Rex rabbits

BACKGROUND

Rex rabbit is famous for its silky and soft fur coat, a characteristic predominantly attributed to its hair follicles. Numerous studies have confirmed the crucial roles of mRNAs and non-coding RNAs (ncRNAs) in regulating key cellular processes such as cell proliferation, differentiation, apoptosis and immunity. However, their involvement in the regulation of the hair cycle in Rex rabbits remains unknown.

RESULTS

In this study, we identified the hair follicle stages of Rex rabbits aged 3 to 5.5 months. Skin samples collected at 4, 5 and 5.5 months, representing the morphological features of the anagen, catagen and telogen stage separately, were finally selected for whole-transcriptome analysis. 25,736 mRNA, 8280 lncRNA, 24,885 circRNA and 1138 miRNA transcripts were identified. 6027 differently expressed mRNAs (DEGs), 2381 differently expressed lncRNAs (DELs), 438 differently expressed circRNAs (DECs) and 167 differently expressed miRNAs (DEMs) were detected in the anagen vs. catagen (AvC) comparison. 4092 DEGs, 1540 DELs, 356 DECs and 141 DEMs were detected in the anagen vs. telogen (AvT) comparison. 2290 DEGs, 779 DELs, 249 DECs and 92 DEMs were detected in the catagen vs. telogen (CvT) comparison. DEGs were primarily enriched in GO items including plasma membrane, integral component of plasma membrane and extracellular space. KEGG enrichment analysis revealed that DEGs were mainly enriched in PI3K-Akt signaling pathway, cell cycle and Wnt signaling pathway (p < 0.05). KEGG analysis showed trans-acting genes of DELs were significantly enriched in Hippo signaling pathway, PI3K-Akt signaling pathway and Melanogenesis. Target genes of DEMs were mainly enriched in MAPK signaling pathway, Wnt signaling pathway, ECM-receptor interaction and Signaling pathways regulating pluripotency of stem cells. Based on the ceRNA mechanism, lncRNA/circRNA-miRNA-mRNA networks were constructed involving 9 DECs, 437 DELs, 50 DEMs and 416 DEGs.

CONCLUSIONS

Totally, this study provides comprehensive insights into the expression patterns of protein-coding genes and non-coding transcripts throughout the HF cycle, and enhancing the understanding of the regulatory mechanisms underlying mammalian hair fiber development.

Transcriptomic analysis of regulatory mechanisms in the telogen-anagen transition of ovine hair follicles

BACKGROUND

Dorper sheep are celebrated for their fast maturation and superior meat quality, with some shedding their wool each spring. Wool shedding occurs naturally due to the hair follicle (HF) cycle, but its regulatory mechanisms remain unclear and need further investigation.

RESULTS

In this study, shedding and non-shedding sheep were selected from the same Dorper flock. Skin samples were collected in September of the first year and January and March of the following years. RNA sequencing was performed on these samples. Principal component analysis (PCA) was used to assess the results. A total of 2536 differentially expressed genes (DEGs) were identified. Using a clustering heatmap and fuzzy clustering analysis three distinct gene expression patterns were identified: A pattern (high expression in anagen), T1 pattern, and T2 pattern (high expression in telogen). For each pattern, differentially expressed genes (DEGs) were analyzed through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Combining this with pathway expression analysis, six A-pattern and fourteen T-pattern pathways linked to telogen-anagen transition in the HF cycle were identified. Networks of key pathways were then constructed. Additionally, key genes were identified in the telogen-anagen transition, including one A-pattern gene and seven T-pattern (T1, 1; T2, 6) genes, using the Maximal Clique Centrality (MCC) tool in Cytoscape. Predicted transcription factors (TFs) involved in key pathways, such as LEF and STAT5B, were identified. Finally, RNA-seq results were confirmed by RT-qPCR.

CONCLUSION

This study highlights critical genes and pathways in the telogen-anagen transition, and transcriptome sequencing along with bioinformatics analysis provides new insights into the regulatory mechanisms of the HF cycle and development.

Combining multiomics to analyze the molecular mechanism of hair follicle cycle change in cashmere goats from Inner Mongolia

Sheep body size can directly reflect the growth rates and fattening rates of sheep and is also an important index for measuring the growth performance of meat sheep.Inner Mongolia Cashmere Goat is a local excellent breed of cashmere and meat dual-purpose, which is a typical heterogeneous indumentum. The hair follicles cycle through periods of vigorous growth (anagen), a regression caused by apoptosis (catagen), and relative rest (telogen). At present, it is not clear which genes affect the cycle transformation of hair follicles and unclear how proteins impact the creation and expansion of hair follicles.we using multi-omics joint analysis methodologies to investigated the possible pathways of transformation and apoptosis in goat hair follicles. The results showed that 917,1,187, and 716 proteins were specifically expressed in anagen, catagen andtelogen. The result of gene ontology (GO) annotation showed that differentially expressed proteins (DEPs) are in different growth cycle periods, and enriched GO items are mostly related to the transformation of cells and proteins. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment result indicated that the apoptosis process has a great impact on hair follicle's growth cycle. The results of the protein interaction network of differential proteins showed that the ribosomal protein family (RPL4, RPL8, RPS16, RPS18, RPS2, RPS27A, RPS3) was the core protein in the network. The results of combined transcriptome and proteomics analysis showed that there were 16,34, and 26 overlapped DEGs and DEPs in the comparison of anagen VS catagen, catagen VS telogen and anagen VS telogen, of which API5 plays an important role in regulating protein and gene expression levels. We focused on API5 and Ribosomal protein and found that API5 affected the apoptosis process of hair follicles, and ribosomal protein was highly expressed in the resting stage of hair follicles. They are both useful as molecular marker candidate genes to study hair follicle growth and apoptosis,and they both have an essential function in the cycle transition process of hair follicles. The results of this study may provide a theoretical basis for further research on the growth and development of hair follicles in Inner Mongolian Cashmere goats.

Effect of Fibroblast Growth Factor 10 and an Interacting Non-Coding RNA on Secondary Hair Follicle Dermal Papilla Cells in Cashmere Goats' Follicle Development Assessed by Whole-Transcriptome Sequencing Technology

Cashmere, a keratinised product of secondary hair follicles (SHFs) in cashmere goats, holds an important place in international high-end textiles. However, research on the complex molecular and signal regulation during the development and growth of hair follicles (HFs), which is essential for the development of the cashmere industry, is limited. Moreover, increasing evidence indicates that non-coding RNAs (ncRNAs) participate in HF development. Herein, we systematically investigated a competing endogenous RNA (ceRNA) regulatory network mediated by circular RNAs (circRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) in skin samples of cashmere goat embryos, using whole-transcriptome sequencing technology. We obtained 6468, 394, and 239 significantly differentially expressed mRNAs, circRNAs, and miRNAs, respectively. These identified RNAs were further used to construct a ceRNA regulatory network, mediated by circRNAs, for cashmere goats at a late stage of HF development. Among the molecular species identified, miR-184 and fibroblast growth factor (FGF) 10 exhibited competitive targeted interactions. In secondary HF dermal papilla cells (SHF-DPCs), miR-184 promotes proliferation, inhibits apoptosis, and alters the cell cycle via the competitive release of FGF10. This study reports that FGF10 and its interaction with ncRNAs significantly affect SHF-DPCs, providing a reference for research on the biology of HFs in cashmere goats and other mammals.

Characterization of Growth Secondary Hair in Min Pig Activated by Follicle Stem Cell Stimulated by Wnt and BMP Signaling Pathway

In China, the national-level protected pig, the Min pig, is characterized by the development of secondary hairs and hair follicles in winter. Factors that dominate the genotype in the growth of secondary hairs are not clear through the concrete cell signaling pathways. This study compared hair phenotypes based on morphological structure, transcriptomics, and potential targeting molecules in the breeds of Min, Berkshire, and Yorkshire pigs. The results indicated that Min pigs have specific characteristics for the growth of secondary hairs compared with the Berkshire and Yorkshire pigs. The transcriptome analyses and quantitative reverse transcription-polymerase chain reaction results revealed that secondary hair growth was activated by follicle stem cells. The specific inhibitors of Wnt and BMP were studied using respective signals. The density of follicles, activity of follicle stem cells, and relative gene expression results have shown that Wnt and BMP stimulate the activity of follicle stem cells, and the Wnt signaling molecule has a significantly better effect than the BMP signaling molecule on stem cells. Wnt and BMP can promote the growth of local secondary hair and gene expression. Therefore, this study was conducted to verify the development mechanisms of secondary hairs, which have potential applications in laboratory animals and comparative medicine.

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.

Comprehensive Transcriptome Analysis of Hair Follicle Morphogenesis Reveals That lncRNA-H19 Promotes Dermal Papilla Cell Proliferation through the Chi-miR-214-3p/β-Catenin Axis in Cashmere Goats

Cashmere is initiated and develops in the fetal stages and the number and density of secondary hair follicles (SHFs) determine cashmere production and quality. Growing evidence indicates that both microRNA (miRNA) and long non-coding RNA (lncRNA) play an indispensable role in hair follicle (HF) growth and development. However, little is known about miRNAs, lncRNAs, and their functions as well as their interactions during cashmere initiation and development. Here, based on lncRNA and miRNA high-throughput sequencing and bioinformatics analysis, we identified 10,485 lncRNAs, 40,639 mRNAs, and 605 miRNAs in cashmere goat skin during HF induction, organogenesis, and cytodifferentiation stages. Among them, 521 lncRNAs, 5976 genes, and 204 miRNAs were differentially expressed (DE). KEGG analysis of DE genes indicated that ECM–receptor interaction and biosynthesis of amino acids were crucial for HF development. Notch, TGF-beta, and Wnt signaling pathways were also identified, which are conventional pathways associated with HF growth and development. Then, the ceRNA regulatory network was constructed, and the impact of lncRNA H19 was investigated in dermal papilla (DP) cells. The MTT, CCK-8, and EdU assays showed that the viability and proliferation of DP cells were promoted by H19, and mechanistic studies suggested that H19 performed its function through the chi-miR-214-3p/β-catenin axis. The present study created a resource for lncRNA, miRNA, and mRNA studies in cashmere morphogenesis. It could contribute to a better understanding of the molecular mechanism of ncRNAs involved in the regulation of HF growth and development.

JAM-A facilitates hair follicle regeneration in Alopecia Areata through functioning as ceRNA to protect VCAN expression in dermal papilla cells

The dermal papilla cells in hair follicles function as critical regulators of hair growth. In particular, alopecia areata (AA) is closely related to the malfunctioning of the human dermal papilla cells (hDPCs). Thus, identifying the regulatory mechanism of hDPCs is important in inducing hair follicle (HF) regeneration in AA patients. Recently, growing evidence has indicated that 3′ untranslated regions (3′ UTR) of key genes may participate in the regulatory circuitry underlying cell differentiation and diseases through a so-called competing endogenous mechanism, but none have been reported in HF regeneration. Here, we demonstrate that the 3′ UTR of junctional adhesion molecule A (JAM-A) could act as an essential competing endogenous RNA to maintain hDPCs function and promote HF regeneration in AA. We showed that the 3′ UTR of JAM-A shares many microRNA (miRNA) response elements, especially miR-221–3p, with versican (VCAN) mRNA, and JAM-A 3′ UTR could directly modulate the miRNA-mediated suppression of VCAN in self-renewing hDPCs. Furthermore, upregulated VCAN can in turn promote the expression level of JAM-A. Overall, we propose that JAM-A 3′ UTR forms a feedback loop with VCAN and miR-221–3p to regulate hDPC maintenance, proliferation, and differentiation, which may lead to developing new therapies for hair loss.

miR-29a-5p Inhibits Prenatal Hair Placode Formation Through Targeting EDAR by ceRNA Regulatory Network

Hair placode formation is an important stage of hair follicle morphogenesis and it is a complex process facilitated by non-coding RNAs. In this study, we conducted whole transcriptome sequencing analysis of skin, heart, liver, lung, and kidney tissues of day 41 (E41) normal and hairless pig embryos, and respectively detected 15, 8, and 515 skin-specific differentially expressed (DE) lncRNAs, miRNAs, and mRNAs. Furthermore, 18 competing endogenous RNA (ceRNA) networks were constructed. Following weighted gene co-expression network analysis (WGCNA) of stages E39, E41, E45, E52, and E60, between normal and hairless pig embryos, only two ceRNAs (lncRNA2162.1/miR-29a-5p/BMPR1b and lncRNA627.1/miR-29a-5p/EDAR) that showed period-specific differential expression in E41 skin were retained. Dual-luciferase reporter assays further indicated that EDAR was a direct, functioning target of miR-29a-5p and that no binding site was found in BMPR1b. Moreover, miR-29a-5p overexpression inhibited the mRNA and protein expression of EDAR while no significant differential expression of BMPR1b was detected. In addition, over-expressed lncRNA627.1 reduces the expression of miR-29a-5p and increase EDAR expression while inhibits lncRNA627.1 resulted in a opposite expression trend. Cell proliferation result demonstrated that lower expression of EDAR and lncRNA627.1 inhibited hair placode precursor cells (HPPCs) proliferation in a manner similar to that shown by over-expressed miR-29a-5p. This study identified that miR-29a-5p inhibited HPPCs proliferation via the suppression of EDAR expression in the EDA/EDAR signaling pathway, while lncRNA627.1 rescues EDAR expression. Our study provides a basis for a better understanding of the mechanisms underlying the ceRNA complex, miR29a-5p/EDAR/lncRNA627.1, that could regulate hair placode formation, which may help decipher diseases affecting human hair.

Single-cell sequencing reveals the new existence form of dermal papilla cells in the hair follicle regeneration of cashmere goats

The problem of human hair loss has caused widespread concern, however, such research is difficult because the periodicity is not obvious and the deeper levels knowledge of dermal papilla (DP) stem cells' differentiation are limited. Here, cashmere goats which have obvious periodicity of hair follicles were used, based on unbiased scRNA sequencing, we constructed DP cell lineage differentiation trajectory and revealed the key genes, signals and functions involved in cell fate decisions. And then we revealed the molecular landscape of hair follicle on regeneration. Revealed that DP cells differentiate into four intermediate cell states at different periodicity: Intermediate-cell-10 showed important functions in the growth and maintenance of cashmere; intermediate-cell-1 acting on apoptosis and cashmere shedding; intermediate-cell-0 initiated new follicular cycles, the migration of hair follicles and the occurrence of cashmere; and intermediate-cell-15 are suggested to be DP progenitor cells. In general, we provide new insights for hair regrowth. At the same time, it provides a new research ideas, directions and molecular landscape for the mechanism of dermal papilla cells.

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.

Delivery of Anti-miRNA-221 for Colorectal Carcinoma Therapy Using Modified Cord Blood Mesenchymal Stem Cells-Derived Exosomes

Background: Exosomes, as natural intercellular information carriers, have great potential in the field of drug delivery. Many studies have focused on modifying exosome surface proteins to allow drugs to specifically target cancer cells.

Methods: In this study, human cord blood mesenchymal stromal cell-derived exosomes were used in the delivery of anti-miRNA oligonucleotides so as to be specifically ingested by tumor cells to perform anti-tumor functions. Mesenchymal stem cells modified by the fusion gene iRGD-Lamp2b were constructed to separate and purify exosomes, and the anti-miRNA-221 oligonucleotide (AMO) was loaded into the exosomes by electroporation.

Results: The AMO-loaded exosomes (AMO-Exos) effectively inhibited the proliferation and clonal formation of colon cancer cells in vitro, and it was further found that AMO-Exos was taken up by tumor cells through interaction with the NRP-1 protein. The results of a xenograft tumor model also showed that iRGD-modified exosomes were obviously enriched in tumor sites, exerting excellent anti-tumor efficacy. In vivo imaging showed that exosomes were mainly distributed in liver, spleen, and lung tissues.

Conclusion: Our results suggest that genetically modified exosomes could be an ideal natural nanostructure for anti-miRNA oligonucleotide delivery.

Cultivation of Hair Matrix Cells from Cashmere Goat Skins and Exemplified Applications

Simple Summary

A large scale of sequencing data pertaining to cashmere growth on cashmere goats have not been cost-effectively used due to the lack of in vitro cellular models, especially for hair matrix cells (HMCs)—the precursors of hair-forming keratinocytes, causing an enormous waste of data resources. Herein, we successfully isolated and cultivated previously unreported HMCs from cashmere goat skins and identified them morphologically and molecularly via their distinct appearance and signature genes’ expression from spatially adjacent dermal papilla cells. Through monitoring the effects of calcium and all-trans retinoic acid on HMCs using various biological techniques, we displayed that the cells are useful models to explore unsolved issues in hair fiber growth on goats. Therefore, our present success paves the road for further utilizing currently deposited data to unveil the secrets of cashmere growth and, ultimately, improve the quantity and quality of animal fibers.

Abstract

A functional interpretation of filtered candidates and predicted regulatory pathways related to cashmere growth from sequencing trials needs available cell models, especially for hair matrix cells (HMCs), whose continual proliferation and differentiation result in rapid hair growth. To fulfill such goals, we herein obtained primary goat HMCs via a microdissection-based method; optimized the selection of the culture medium and coating substances for better cell maintenance; and exemplified their usefulness through examining the effects of calcium and all-trans retinoic acid (ATRA) on cells using immunoblotting, flow cytometry, and other techniques. As a result, we successfully acquired primary and passaged goat HMCs with typical keratinocyte morphology. Calcium-free RPMI (Roswell Park Memorial Institute) 1640 and MEM (minimum Eagle’s medium) outperformed normal DMEM/F12 (Dulbecco’s modified Eagle’s medium/Nutrient Mixture F-12) on long-term cell maintenance, whereas serum-free media K-SFM and EpiLife failed to support cell growth. HMCs differed molecularly and morphologically from their neighbor dermal papilla cells on expressions of feature genes, such as HOXC13, and on characteristic keratinocyte-like appearances versus fibroblast shapes, respectively. Higher calcium concentrations significantly stimulated the expression of the genes (e.g., KRT1 and IVL) involved in keratinocyte differentiation and, promoted cell proliferation. Moreover, 10⁻⁵ M ATRA obviously boosted goat HMC expansions and changed their cell cycle distributions compared to the controls. Our study shines a light on researches exploring the mechanisms underlying the growth of cashmere.

Analysis of histological and microRNA profiles changes in rabbit skin development

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 twenty-fourth 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.

Synchronous profiling and analysis of mRNAs and ncRNAs in the dermal papilla cells from cashmere goats

Background

Dermal papilla cells (DPCs), the “signaling center” of hair follicle (HF), delicately master continual growth of hair in mammals including cashmere, the fine fiber annually produced by secondary HF embedded in cashmere goat skins. Such unparalleled capacity bases on their exquisite character in instructing the cellular activity of hair-forming keratinocytes via secreting numerous molecular signals. Past studies suggested microRNA (miRNAs) and long non-coding RNAs (lncRNAs) play essential roles in a wide variety of biological process, including HF cycling. However, their roles and related molecular mechanisms in modulating DPCs secretory activities are still poorly understood.

Results

Here, we separately cultivated DPCs and their functionally and morphologically distinct dermal fibroblasts (DFs) from cashmere goat skins at anagen. With the advantage of high throughput RNA-seq, we synchronously identified 2540 lncRNAs and 536 miRNAs from two types of cellular samples at 4th passages. Compared with DFs, 1286 mRNAs, 18 lncRNAs, and 42 miRNAs were upregulated, while 1254 mRNAs, 53 lncRNAs and 44 miRNAs were downregulated in DPCs. Through overlapping with mice data, we ultimately defined 25 core signatures of DPCs, including HOXC8 and RSPO1, two crucial activators for hair follicle stem cells (HFSCs). Subsequently, we emphatically investigated the impacts of miRNAs and lncRNAs (cis- and trans- acting) on the genes, indicating that ncRNAs extensively exert negative and positive effects on their expressions. Furthermore, we screened lncRNAs acting as competing endogenous RNAs (ceRNAs) to sponge miRNAs and relief their repressive effects on targeted genes, and constructed related lncRNAs-miRNAs-HOXC8/RSPO1 interactive lines using bioinformatic tools. As a result, XR_310320.3-chi-miR-144-5p-HOXC8, XR_311077.2-novel_624-RSPO1 and others lines appeared, displaying that lncRNAs might serve as ceRNAs to indirectly adjust HFSCs status in hair growth.

Conclusion

The present study provides an unprecedented inventory of lncRNAs, miRNAs and mRNAs in goat DPCs and DFs. We also exhibit some miRNAs and lncRNAs potentially participate in the modulation of HFSCs activation via delicately adjusting core signatures of DPCs. Our report shines new light on the latent roles and underlying molecular mechanisms of ncRNAs on hair growth.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5861-4) contains supplementary material, which is available to authorized users.

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.