Hair follicle dermal papilla cells at a glance

HaCaT‑conditioned medium supplemented with the small molecule inhibitors SB431542 and CHIR99021 and the growth factor PDGF‑AA prevents the dedifferentiation of dermal papilla cells in vitro

Hair loss, including alopecia, is a common and distressing problem for men and women, and as a result, there is considerable interest in developing treatments that can prevent or reverse hair loss. Dermal papillae closely interact with epidermal cells and play a key role during hair follicle induction and hair morphogenesis. As dermal papilla cells (DPCs) lose their hair‑inducing ability in monolayer cultures in vitro, it is difficult to obtain de novo hair follicle structures following DPC transplantation in vivo. The present study aimed to explore culture conditions to maintain DPC characteristics using conditioned media (CM) from the supernatant of cultured HaCaT keratinocyte cells supplemented with other components. Initially, it was observed that during passaging of in vitro monolayer DPC cultures, the Wnt/β‑catenin pathway was repressed, while the TGF‑β/Smad pathway was activated, and that HaCaT cells cultivated in 1% fetal bovine serum had higher levels of expression of Wnt3a and Wnt10b compared with normal keratinocytes. Culturing of high‑passage (P7) DPCs in CM from HaCaT cells (HaCaT‑CM) actively stimulated cell proliferation and maintained Sox2 and Versican expression levels. Supplementation of HaCaT‑CM with SB431542 (SB, a TGF‑β receptor inhibitor), CHIR99021, (CHIR, a GSK3α/β inhibitor and activator of Wnt signaling) and platelet‑derived growth factor (PDGF)‑AA further increased the expression levels of Sox2, Versican and alkaline phosphatase (ALP) in P7 DPCs. Three‑dimensional culture of P7 DPCs using hanging drop cultures in HaCaT‑CM supplemented with SB, CHIR and PDGF‑AA resulted in larger cell aggregates and a further significant upregulation of Sox2, ALP and Versican expression levels. Taken together, these findings demonstrated that HaCaT‑CM supplemented with SB, CHIR and PDGF‑AA may preserve the hair‑inducing ability of high‑passage DPCs and may therefore be useful in reconstructing new hair follicles in vivo.

Wnt10b promotes hair follicles growth and dermal papilla cells proliferation via Wnt/β-Catenin signaling pathway in Rex rabbits

Wnt signaling plays an important role in the growth and development of hair follicles (HFs). Among the signaling molecules, Wnt10b was shown to promote the differentiation of primary skin epithelial cells toward the hair shaft and inner root sheath of the HF cells in mice in vitro. Whisker HFs were isolated from Rex rabbits and cultured in vitro to measure hair shaft growth. Meanwhile, dermal papilla cells (DPCs) were isolated and cultured in vitro. Treatment with AdWnt10b or the Wnt/β-Catenin Pathway inhibitor, XAV939, assessed the DPCs proliferation by CCK-8 assay. And the cell cycle was also analyzed by flow cytometry. We found that Wnt10b could promote elongation of the hair shaft, whereas XAV-939 treatment could eliminated this phenomenon. AdWnt10b treatment promoted the proliferation and induced G1/S transition of DPCs. AdWnt10b stimulation up-regulated β-Catenin protein in DPCs. Inhibition of Wnt/β-Catenin signaling by XAV-939 could decreased the basal and Wnt10b-enhanced proliferation of DPCs. And could also suppress the cell cycle progression in DPCs. In summary, our study demonstrates that Wnt10b could promote HFs growth and proliferation of DPCs via the Wnt/β-Catenin signaling pathway in Rex rabbits.

Hair Growth Promotion Effect of Nelumbinis Semen Extract with High Antioxidant Activity

This study investigated the hair regeneration promotion and hair loss prevention properties of Nelumbinis Semen (NS) extract in vitro and in vivo. The effect of NS on the proliferation and migration of human dermal papilla cells (hDPCs) was measured in vitro via CCK-8 and scratch migration assays, after which the antioxidant activity of NS was also quantified. NS extracts were then applied to the back of 7-week-old C57BL/6 mice for 3 weeks to monitor hair growth patterns and hair follicle (HF) histology. The mice were divided into three groups: negative control group (NC; DMSO), positive control group (PC; 3% minoxidil), and experimental group (NS extract 1,000 ppm). Moreover, to study the molecular mechanisms by which NS extract regenerates hair growth, real-time PCR was used to analyze factors related to the hair growth cycle. The NS extracts were found to possess high antioxidant properties due to their high flavonoid contents and electron-donating ability. Moreover, NS extracts enhanced hDPC proliferation and migration in a concentration-dependent manner (15.63–125 ppm). The hair growth index and growth area of the NS group (2.81 score, 81%) on day 14 were higher than those of the PC group (2.65 score, 68%) (p < 0.05). Additionally, the HFs of the NS group were located deep in the subcutis, similar to the PC group with developed hair roots. Moreover, the mRNA expression of VEGF and IGF-1 was higher in the NS group compared to the PC group, whereas TGF-β1 expression was lower (p < 0.05). Our findings indicate that NS modulates hair growth by increasing IGF-1 and VEGF expression while inhibiting that of TGF-β1. Therefore, our findings suggest that NS extract is a promising new hair loss treatment derived from a natural substance that helps promote hair growth and prevent hair loss.

Impact of adipose-derived stem cells on engineering hair follicle germ-like tissue grafts for hair regenerative medicine

Hair regenerative medicine has emerged as a promising treatment strategy for severe hair loss, such as end-stage androgenetic alopecia. Various approaches to engineering three-dimensional tissue grafts have been explored since they drive the ability to regenerate hair follicles when transplanted. In the present study, we demonstrated the assembly of human adipose-derived stem cells (hASCs) into hair follicle germ (HFG)-like aggregates for de novo hair regeneration. We mixed human dermal papilla cells (hDPCs), murine embryonic epithelial cells, and hASCs in suspension, and allowed them to form aggregates. During three days of culture, cells initially formed a single aggregate with a random distribution of the three cell types, but the epithelial and dermal papilla cells subsequently separated from each other and formed a dumbbell-shaped HFG, with hASCs localized on the hDPC aggregate side. The involvement of hASCs significantly increased gene expression associated with hair morphogenesis compared to HFGs without hASCs. The self-organization of the three cell types was observed in our scalable lab-made chip device. HFGs containing hASCs efficiently generated hair shafts upon transplantation to nude mice, while only a few shafts were generated with HFGs without hASCs. This approach may be a promising strategy for fabricating tissue grafts for hair regenerative medicine.

3D skin models in domestic animals

The skin is a passive and active barrier which protects the body from the environment. Its health is essential for the accomplishment of this role. Since several decades, the skin has aroused a strong interest in various fields (for e.g. cell biology, medicine, toxicology, cosmetology, and pharmacology). In contrast to other organs, 3D models were mostly and directly elaborated in humans due to its architectural simplicity and easy accessibility. The development of these models benefited from the societal pressure to reduce animal experiments. In this review, we first describe human and mouse skin structure and the major differences with other mammals and birds. Next, we describe the different 3D human skin models and their main applications. Finally, we review the available models for domestic animals and discuss the current and potential applications.

The effect of androgen on wool follicles and keratin production in Hetian sheep

To investigate the optimal androgen concentration for culturing Hetian sheep wool follicle and to detect effects of androgen concentration on wool follicle cell proliferation and apoptosis using immunofluorescence labeling and real-time quantitative fluorescence determinations of wool keratin-associated protein gene expression levels. Wool follicles were isolated by microdissection and wool follicles and skin pieces were cultured in various concentrations of dihydrotestosterone (DHT) in culture medium. Next, daily lengthwise growth measurements of wool follicles were obtained using a microscopic micrometer. Cultured Hetian wool follicles were stained using the SACPIC method to reveal wool follicle structure, while sheep skin slices were used to observe cell proliferation by immunostaining and cell apoptosis using the TUNEL method. At the molecular biological level, keratin-associated protein (Kap) gene expression was studied using wool follicles cultured for various numbers of days in vitro. Effects of androgen concentrations on Hetian wool follicle growth and development were experimentally studied. EdU proliferation assays revealed that androgen promoted cell proliferation within wool follicle dermal papillae. TUNEL apoptosis detection demonstrated that androgen treatment could delay cell apoptosis. Quantitative reverse transcription polymerase chain reaction (qPCR) results demonstrated that gene expression level patterns of Hetian mountain sheep super-high sulfur protein. Kap1.1, KIF1.2, Kap2.12 and Kap4.2 gene expression level of the mountainous experimental group was significantly higher than plains Hetian sheep. An androgen concentration of 100 nM can promote the growth of Hetian wool follicle cells in vitro, resulting in overexpression of some genes of the Kap family.

Neural progenitor cell-derived nanovesicles promote hair follicle growth via miR-100

BACKGROUND

Accumulating evidence shows that mesenchymal stem cell-derived extracellular vesicles (EVs) hold great promise to promote hair growth. However, large-scale production of EVs is still a challenge. Recently, exosome-mimetic nanovesicles (NV) prepared by extruding cells have emerged as an alternative strategy for clinical-scale production. Here, ReNcell VM (ReN) cells, a neural progenitor cell line was serially extruded to produce NV.

RESULTS

ReN-NV were found to promote dermal papilla cell (DPC) proliferation. In addition, in a mouse model of depilation-induced hair regeneration, ReN-NV were injected subcutaneously, resulting in an acceleration of hair follicle (HF) cycling transition at the site. The underlying mechanism was indicated to be the activation of Wnt/β-catenin signaling pathway. Furthermore, miR-100 was revealed to be abundant in ReN-NV and significantly up-regulated in DPCs receiving ReN-NV treatment. miR-100 inhibition verified its important role in ReN-NV-induced β-catenin signaling activation.

CONCLUSION

These results provide an alternative agent to EVs and suggest a strategy for hair growth therapy.

Improvement of Cell Proliferation and Antioxidant Activity of Silymarin in Hair Follicles Dermal Papillae Isolated from the Human Scalp: Comparison with Vitamin C Effects

Introduction:

Nowadays, hair loss is becoming a major problem for a large number of people. The main factors affecting hair growth include racial, gender, genetics, and hormonal. Furthermore, environment, physiology, and nutrition are the tools that are affecting hair growth.

Materials and Methods:

This article analyses the effects of silymarin and Vitamin C on the proliferation of dermal papilla cells (DPCs), COX2, inducible nitric oxide synthase (iNOS), total anti-oxidant capacity (TAC), and reactive oxygen species (ROS). The DPCs of the hair follicle treated by 50 and 100 μM of silymarin and 100 μM of Vitamin C on days 2, 7, and 14.

Results:

A comparatively effect of silymarin and Vitamin C demonstrated that Vitamin C is more effective in the stimulation of dermal papillae in cell culture. Furthermore, the stimulation effects of silymarin are attributed to its antioxidant activity of the cells.

Conclusion:

The overall result shows that cell proliferation and TAC significantly increased. However, iNOS, ROS, and COX2 levels were decreased.

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

The European rabbit (Oryctolagus cuniculus) is the only representative of its genus living in present-day Europe and North Africa, and all domestic rabbits are descendants of this one species, which is native to the Iberian Peninsula. There are over 300 breeds of rabbits that differ in size, coat color, length of ears and type of fur. Rabbits are bred for various reasons, such as for laboratory animals and a source of meat, wool and fur, as well as for pets and exhibition animals. The hair coat is a important economic trait of rabbits. Its development and quality are influenced by various factors, both environmental and genetic. The genetic mechanisms underlying its development have not been thoroughly researched. The aim of this review is to discuss the domestication of rabbits and the different aspects of rabbit genetics. A brief review of the properties of rabbit hair coat, hair coat development and hair cycle will be provided, followed by discussion of the factors regulating hair coat development, molecular control of hair coat development and the role of non-coding RNAs in the regulation of gene expression in the hair follicles of rabbits. Information about genetic regulation of pathways could provide useful tools for improving hair coat quality and be of practical use in rabbit breeding.

Heparan Sulfate Proteoglycans: Key Mediators of Stem Cell Function

Heparan sulfate proteoglycans (HSPGs) are an evolutionarily ancient subclass of glycoproteins with exquisite structural complexity. They are ubiquitously expressed across tissues and have been found to exert a multitude of effects on cell behavior and the surrounding microenvironment. Evidence has shown that heterogeneity in HSPG composition is crucial to its functions as an essential scaffolding component in the extracellular matrix as well as a vital cell surface signaling co-receptor. Here, we provide an overview of the significance of HSPGs as essential regulators of stem cell function. We discuss the various roles of HSPGs in distinct stem cell types during key physiological events, from development through to tissue homeostasis and regeneration. The contribution of aberrant HSPG production to altered stem cell properties and dysregulated cellular homeostasis characteristic of cancer is also reviewed. Finally, we consider approaches to better understand and exploit the multifaceted functions of HSPGs in influencing stem cell characteristics for cell therapy and associated culture expansion strategies.

Maintaining Hair Inductivity in Human Dermal Papilla Cells: A Review of Effective Methods

The dermal papilla comprises mesenchymal cells in hair follicles, which play the main role in regulating hair growth. Maintaining the potential hair inductivity of dermal papilla cells (DPCs) and dermal sheath cells during cell culture is the main factor in in vitro morphogenesis and regeneration of hair follicles. Using common methods for the cultivation of human dermal papilla reduces the maintenance requirements of the inductive capacity of the dermal papilla and the expression of specific dermal papilla biomarkers. Optimizing culture conditions is therefore crucial for DPCs. Moreover, exosomes appear to play a key role in regulating the hair follicle growth through a paracrine mechanism and provide a functional method for treating hair loss. The present review investigated the biology of DPCs, the molecular and cell signaling mechanisms contributing to hair follicle growth in humans, the properties of the dermal papilla, and the effective techniques in maintaining hair inductivity in DPC cultures in humans as well as hair follicle bioengineering.

Wanted, dead and alive: Why a multidisciplinary approach is needed to unlock hair treatment potential

Human recorded history is littered with attempts to improve the perceived appearance of scalp hair. Throughout history, treatments have included both biological and chemical interventions. Hair "quality" or "perceived appearance" is regulated by multiple biological intervention opportunities: adding more hairs by flipping follicles from telogen to anagen, or delaying anagen follicles transiting into catagen; altering hair "apparent amount" by modulating shaft diameter or shape; or, in principle, altering shaft physical properties changing its synthesis. By far the most common biological intervention strategy today is to increase the number of hairs, but to date this has proven difficult and has yielded minimal benefits. Chemical intervention primarily consists of active material surface deposition to improve shaft shine, fibre-fibre interactions and strength. Real, perceptible benefits will best be achieved by combining opportunity areas across the three primary sciences: biology, chemistry and physics. Shaft biogenesis begins with biology: proliferation in the germinative matrix, then crossing "Auber's Critical Line" and ceasing proliferation to synthesize shaft components. Biogenesis then shifts to oxidative chemistry, where previously synthesized components are organized and cross-linked into a shaft. We herein term the crossing point from biology to chemistry as "The Orwin Threshold." Historically, hair biology and chemistry have been conducted in different fields, with biological manipulation residing in biomedical communities and hair shaft chemistry and physics within the consumer care industry, with minimal cross-fertilization. Detailed understanding of hair shaft biogenesis should enable identification of factors necessary for optimum hair shaft production and new intervention opportunities.

Twist1 Contributes to the Maintenance of Some Biological Properties of Dermal Papilla Cells in vitro by Forming a Complex With Tcf4 and β-Catenin

OBJECTIVE

During hair follicle regeneration, hair follicle stem cells (HFSCs) are regulated by signals from dermal papilla cells (DPCs). Previously we found that Tcf4 could promote the proliferation of DPCs. In this study, we focused on whether and how the biological properties of Tcf4-induced DPCs were regulated by Twist1.

METHODS

Twist1 was overexpressed or knocked down in DPCs following different adenovirus or lentivirus infection. Phase-contrast microscopy was used to observe the agglutinative growth of DPCs. The CCK-8 assay was used to test the proliferation of DPCs. Western blot and qPCR experiments were used to determine the expression of HGF, IGF-1, VEGF, c-myc, survivin, and CyclinD1 in DPCs. ELISAs were used to test the growth factors secreted by DPCs. Conditional medium culture was used to detect the inductive ability of DPCs. Co-immunoprecipitation and immunofluorescence were used to test the binding of Twist1, Tcf4, and β-catenin in DPCs. Immunofluorescence was also used to test the expression of Twist1, Tcf4, and KRT15 in hair follicles.

RESULTS

Twist1 induced DPC agglutinative growth and proliferation. Twist1 upregulated the expression of downstream target genes downstream of Tcf4, c-myc, survivin, in Tcf4-induced DPCs, as well as the expression and secretion of growth factors HGF, IGF-1, VEGF, which had the ability to induce hair follicle growth. The conditional medium from Twist1-treated DPCs increased the expression of KRT40 and MSX2 in HaCaT cells. Twist1 and Tcf4 co-localized in DPCs both in vitro and in vivo. Anti-Twist1 precipitated Tcf4 and β-catenin.

CONCLUSION

These results indicate that Tcf4 and Twist1 play a synergistic role in regulating the hair follicle induction ability of DPCs. Twist1 functions by forming a ternary complex with Tcf4 and β-catenin. Thus, we report new data that elucidate whether and how Twist1 regulates some biological properties of DPCs.

LncRNA-599547 contributes the inductive property of dermal papilla cells in cashmere goat through miR-15b-5p/Wnt10b axis

The lncRNA-599547 (619-nt in length) is identified in secondary hair follicle (SHF) of cashmere goat, but its functional roles in regulating the inductive property of dermal papilla cells (DPCs) remains unknown. We found that lncRNA-599547 had significantly higher expression in dermal papilla of cashmere goat SHF at anagen than its counterpart at telogen. The overexpression of lncRNA-599547 led to a significant increase of ALP and LEF1 expression in DPCs (p < 0.05), whereas, the siLncRNA-1 mediated silencing of lncRNA-599547 significantly down-regulated the expression of ALP and LEF1 in DPCs (p < 0.05). Based on biotin-labeled RNA pull-down assay, we found that lncRNA-599547 directly interacted with chi-miR-15b-5p in DPCs. Based on both overexpression and silencing analysis of lncRNA-599547, our results indicate that lncRNA-599547 promotes the expression of Wnt10b in DPCs but without modulating its promoter methylation level. Using the mRNA-3'UTR fragments of goat Wnt10b containing the predicted binding sites of chi-miR-15b-5p in Dual-luciferase Reporter Assays, we show that lncRNA-599547 modulates the expression of Wnt10b at the chi-miR-15b-5p mediated post-transcriptional level. Taken together, our results indicate that lncRNA-599547 sponges miR-15b-5p to positively regulate the expression of Wnt10 gene, and thereby contributes the inductive property of DPCs in cashmere goat.

β-catenin-mediated hair growth induction effect of 3,4,5-tri-O-caffeoylquinic acid

The hair follicle is a complex structure that goes through a cyclic period of growth (anagen), regression (catagen), and rest (telogen) under the regulation of several signaling pathways, including Wnt/ β-catenin, FGF, Shh, and Notch. The Wnt/β-catenin signaling is specifically involved in hair follicle morphogenesis, regeneration, and growth. β-catenin is expressed in the dermal papilla and promotes anagen induction and duration, as well as keratinocyte regulation and differentiation. In this study, we demonstrated the activation of β-catenin by a polyphenolic compound 3,4,5-tri-O-caffeoylquinic acid (TCQA) in mice model and in human dermal papilla cells to promote hair growth cycle. A complete regrowth of the shaved area of C3H mice was observed upon treatment with TCQA. Global gene expression analysis using microarray showed an upregulation in hair growth-associated genes. Moreover, the expression of β-catenin was remarkably upregulated in vivo and in vitro. These findings suggest that β-catenin activation by TCQA promoted the initiation of the anagen phase of the hair cycle.

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.

The effect of hypoxia on the proliferation capacity of dermal papilla cell by regulating lactate dehydrogenase

Hypoxia is of great significance for stem cells to maintain the proliferation and differentiation capacity. As a specialized mesenchymal component of the hair follicle (HF), the dermal papilla cell (DPC) not only regulates HF cycle, but also plays a pivotal role in differentiating hair follicle stem cell(HFSC) into HF. However, whether hypoxia could affect DPCs on proliferation or metabolism remains unclear. In our study, DPCs were cultured in normoxia (20%O₂) or hypoxia (5%O₂). Cell viability assays were performed, and lactate dehydrogenase (LDH) activity and lactate level in DPCs were detected. After that, LDH was overexpressed or knocked down in DPCs; then, the expression of protein markers (ALP, Ki‐67) was assessed by Western blotting, and cell proliferation was also detected after overexpression or knockdown of LDH. Hypoxia did show positive effect on proliferation of DPCs. The LDH activity of DPCs cultured under hypoxic condition was significantly higher than that of cultured under normoxic condition. Overexpression of LDH significantly up‐regulates the expression of ALP and Ki‐67 compared with knockdown and negative control. Cell proliferation was also promoted in DPCs with elevated LDH. Our findings showed that the proliferation activity of DPCs could be stimulated under hypoxia. Meanwhile, LDH plays an important role in maintaining the activity of DPCs in hypoxic condition.

Chi-miR-30b-5p inhibits dermal papilla cells proliferation by targeting CaMKIIδ gene in cashmere goat

Background

During goat embryonic morphogenesis and postnatal initiation of hair follicle (HF) regeneration, dermal papilla (DP) cells play a vital role in hair formation. Growing evidence shows that microRNAs (miRNAs) participate in HF development and DP cell proliferation. However, the molecular mechanisms have not been thoroughly investigated.

Result

In this study, we utilized miRNA sequencing (miRNA-Seq) to identify differentially expressed miRNAs at different HF cycling stages (anagen and telogen). MiRNA-Seq has identified 411 annotated miRNAs and 130 novel miRNAs in which 29 miRNAs were up-regulated and 32 miRNAs were down-regulated in the anagen phase compared to the telogen phase. Target gene prediction and functional enrichment analysis indicated some major biological pathways related to hair cycling, such as Wnt signaling pathways, ECM-receptor interaction, VEGF signaling pathway, biosynthesis of amino acids, metabolic pathways, ribosome and oxidative phosphorylation. Also, we explored the function of chi-miR-30b-5p in regulating hair growth cycle. Similar to the HF cycling, DP cells were isolated from skin and used to investigate miRNA functions. The MTT and EdU assays showed that the viability and proliferation of DP cells were inhibited or promoted after the transfection of chi-miR-30b-5p mimic or inhibitor, respectively. Bioinformatics analysis revealed CaMKIIδ as a candidate target gene of chi-miR-30b-5p, and the dual-luciferase and western blot assay demonstrated that chi-miR-30b-5p bound to the 3’UTR of CaMKIIδ and further inhibited its translation.

Conclusion

Chi-miR-30b-5p was found to be highly expressed in the telogen than that in the anagen phase and could inhibit the proliferation of DP cells by targeting CaMKIIδ. Our study provides new information on the regulatory functions of miRNAs during HF development.

Analysis of lncRNAs Expression Profiles in Hair Follicle of Hu Sheep Lambskin

Lambskin of the Hu sheep exhibits high economic value due to its water-wave pattern. Wool curvature is the key factor of the pattern types and quality of lambskin, and it is formed by the interaction between dermal papilla cells and hair matrix cells in the hair follicle, which is regulated by various genes and signaling pathways. Herein, three full-sibling pairs of two-day-old healthy lambs (n = 6) were divided into a straight wool group (ST) and small waves group (SM) with three repetitions. RNA-seq was applied to determine the expression profile of mRNAs and lncRNAs in Hu sheep hair follicles. 25 differentially expressed mRNAs and 75 differentially expressed lncRNAs were found between SM and ST. FGF12, ATP1B4, and TCONS_00279168 were probably associated with hair follicle development. Then, Gene Ontology (GO) and KEGG enrichment analysis were implemented for the functional annotation of target genes of differentially expressed lncRNAs. The results showed that many genes, such as FGF12 and ATP1B4, were found enriched in PI3K-Akt signaling, MAPK signaling, and Ras signaling pathway associated with hair follicle growth and development. In addition, the interaction network of differentially expressed lncRNAs and mRNAs showed that a total of 6 differentially expressed lncRNAs were associated with 12 differentially expressed mRNAs, which may be as candidate mRNAs and lncRNAs. TCONS_00279168 may target ATP1B4 and FGF12 to regulate MAPK, PI3K-Akt, Ras signaling pathways involved in the sheep hair follicle development process. These results will provide the basis for exploring hair follicle development.

The local hypothalamic-pituitary-adrenal axis in cultured human dermal papilla cells

BACKGROUND

Stress is an important cause of skin disease, including hair loss. The hormonal response to stress is due to the HPA axis, which comprises hormones such as corticotropin releasing factor (CRF), adrenocorticotropic hormone (ACTH), and cortisol. Many reports have shown that CRF, a crucial stress hormone, inhibits hair growth and induces hair loss. However, the underlying mechanisms are still unclear. The aim of this study was to examine the effect of CRF on human dermal papilla cells (DPCs) as well as hair follicles and to investigate whether the HPA axis was established in cultured human DPCs.

RESULTS

CRF inhibited hair shaft elongation and induced early catagen transition in human hair follicles. Hair follicle cells, both human DPCs and human ORSCs, expressed CRF and its receptors and responded to CRF. CRF inhibited the proliferation of human DPCs through cell cycle arrest at G2/M phase and induced the accumulation of reactive oxygen species (ROS). Anagen-related cytokine levels were downregulated in CRF-treated human DPCs. Interestingly, increases in proopiomelanocortin (POMC), ACTH, and cortisol were induced by CRF in human DPCs, and antagonists for the CRF receptor blocked the effects of this hormone.

CONCLUSION

The results of this study showed that stress can cause hair loss by acting through stress hormones. Additionally, these results suggested that a fully functional HPA axis exists in human DPCs and that CRF directly affects human DPCs as well as human hair follicles under stress conditions.

Human Hair Outer Root Sheath Cells and Platelet-Lysis Exosomes Promote Hair Inductivity of Dermal Papilla Cell

BACKGROUND

Hair loss is a prevalent medical problem in both men and women. Maintaining the potential hair inductivity of dermal papilla cells (DPCs) during cell culture is the main factor in hair follicle morphogenesis and regeneration. The present study was conducted to compare the effects of different concentrations of human hair outer root sheath cell (HHORSC) and platelet lysis (PL) exosomes to maintain hair inductivity of the human dermal papilla cells (hDPCs).

METHODS

In this study, hDPCs and HHORSCs were isolated from healthy hair samples. Specific markers of hDPCs (versican, α-SMA) and HHORSCs (K15) were evaluated using flow cytometric and immunocytochemical techniques. The exosomes were isolated from HHORSCs and PL with ultracentrifugation technique. Western blot was used to detect specific markers of HHORSCs and PL exosomes. Particle size and distribution of the exosomes were analyzed by NanoSight dynamic light NanoSight Dynamic Light Scattering. Different methods such as proliferation test (MTS assay), migration test (Transwell assay) were used to evaluate the effects of different concentrations of exosomes (2,550,100 µg/ml) derived from HHORSC and PL on hDPCs. Expression of specific genes in the hair follicle inductivity, including ALP, versican and α-SMA were also evaluated using real time-PCR.

RESULTS

The flow cytometry of the specific cytoplasmic markers of the hDPCs and HHORSCs showed expression of versican (77%), α-SMA (55.2%) and K15 (73.2%). The result of particle size and distribution of the exosomes were analyzed by NanoSight dynamic light NanoSight Dynamic Light Scattering, which revealed the majority of HHORSC and PL exosomes were 30-150 nm. For 100 µg/ml of HHORSC exosomes, the expressions of ALP, versican and α-SMA proteins respectively increased by a factor of 2.1, 1.7and 1.3 compared to those in the control group.

CONCLUSION

In summary, we applied HHORSC exosomes as a new method to support hair inductivity of dermal papilla cells and improve the outcome for the treatment of hair loss.

Reconstructed human skin shows epidermal invagination towards integrated neopapillae indicating early hair follicle formation in vitro

Application of reconstructed human Skin (RhS) is a promising approach for the treatment of extensive wounds and for drug efficacy and safety testing. However, incorporating appendages, such as hair follicles, into RhS still remains a challenge. The hair follicle plays a critical role in thermal regulation, dispersion of sweat and sebum, sensory and tactile functions, skin regeneration, and repigmentation. The aim of this study was to determine whether human neopapilla could be incorporated into RhS (differentiated epidermis on fibroblast and endothelial cell populated dermis) and whether the neopapillae maintain their inductive follicular properties in vitro. Neopapillae spheroids, constructed from expanded and self‐aggregating dermal papilla cells, synthesized extracellular matrix typically found in follicular papillae. Compared with dermal fibroblasts, neopapillae showed increased expression of multiple genes (Wnt5a, Wnt10b, and LEF1) known to regulate hair development and also increased secretion of CXCL1, which is a strong keratinocyte chemoattractant. When neopapillae were incorporated into the dermis of RhS, they stimulated epidermal down‐growth resulting in engulfment of the neopapillae sphere. Similar to the native hair follicle, the differentiated invaginating epidermis inner side was keratin 10 positive and the undifferentiated outer side keratin 10 negative. The outer side was keratin 15 positive confirming the undifferentiated nature of these keratinocytes aligning a newly formed collagen IV, laminin V positive basement membrane within the hydrogel. In conclusion, we describe a RhS model containing neopapillae with hair follicle‐inductive properties. Importantly, epidermal invagination occurred to engulf the neopapillae, thus demonstrating in vitro the first steps towards hair follicle morphogenesis in RhS.

Culture and Differentiation of Human Hair Follicle Dermal Papilla Cells in a Soft 3D Self-Assembling Peptide Scaffold

Hair follicle dermal papilla cells (HFDPC) are a specialized cell population located in the bulge of the hair follicle with unique characteristics such as aggregative behavior and the ability to induce new hair follicle formation. However, when expanded in conventional 2D monolayer culture, their hair inductive potency is rapidly lost. Different 3D culture techniques, including cell spheroid formation, have been described to restore, at least partially, their original phenotype, and therefore, their hair inductive ability once transplanted into a recipient skin. Moreover, hair follicle dermal papilla cells have been shown to differentiate into all mesenchymal lineages, but their differentiation potential has only been tested in 2D cultures. In the present work, we have cultured HFDPC in the 3D self-assembling peptide scaffold RAD16-I to test two different tissue engineering scenarios: restoration of HFDPC original phenotype after cell expansion and osteogenic and adipogenic differentiation. Experimental results showed that the 3D environment provided by RAD16-I allowed the restoration of HFDPC signature markers such as alkaline phosphatase, versican and corin. Moreover, RAD16-I supported, in the presence of chemical inductors, three-dimensional osteogenic and adipogenic differentiation. Altogether, this study suggests a potential 3D culture platform based on RAD16-I suitable for the culture, original phenotype recovery and differentiation of HFDPC.

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.

Macrophage-Derived Extracellular Vesicle Promotes Hair Growth

Hair loss is a common medical problem affecting both males and females. Dermal papilla (DP) cells are the ultimate reservoir of cells with the potential of hair regeneration in hair loss patients. Here, we analyzed the role of macrophage-derived Wnts (3a and 7b) and macrophage extracellular vesicles (MAC-EVs) in promoting hair growth. We studied the proliferation, migration, and expression of growth factors of human-DP cells in the presence or absence of MAC-EVs. Additionally, we tested the effect of MAC-EV treatment on hair growth in a mouse model and human hair follicles. Data from western blot and flow cytometry showed that MAC-EVs were enriched with Wnt3a and Wnt7b, and more than 95% were associated with their membrane. The results suggest that Wnt proteins in MAC-EVs activate the Wnt/β-catenin signaling pathways, which leads to activation of transcription factors (Axin2 and Lef1). The MAC-EVs significantly enhanced the proliferation, migration, and levels of hair-inductive markers of DP cells. Additionally, MAC-EVs phosphorylated AKT and increased the levels of the survival protein Bcl-2. The DP cells treated with MAC-EVs showed increased expression of vascular endothelial growth factor (VEGF) and keratinocyte growth factor (KGF). Treatment of Balb/c mice with MAC-EVs promoted hair follicle (HF) growth in vivo and also increased hair shaft size in a short period in human HFs. Our findings suggest that MAC-EV treatment could be clinically used as a promising novel anagen inducer in the treatment of hair loss.

Thymosin β4 Identified by Transcriptomic Analysis from HF Anagen to Telogen Promotes Proliferation of SHF-DPCs in Albas Cashmere Goat

Increasing cashmere yield is one of the important goals of cashmere goat breeding. To achieve this goal, we screened the key genes that can improve cashmere performance. In this study, we used the RNA raw datasets of the skin and dermal papilla cells of secondary hair follicle (SHF-DPCs) samples of hair follicle (HF) anagen and telogen of Albas cashmere goats and identified a set of significant differentially expressed genes (DEGs). To explore potential associations between gene sets and SHF growth features and to identify candidate genes, we detected functional enrichment and constructed protein-protein interaction (PPI) networks. Through comprehensive analysis, we selected Thymosin β4 (Tβ4), Rho GTPase activating protein 6 (ARHGAP6), ADAM metallopeptidase with thrombospondin type 1 motif 15, (ADAMTS15), Chordin (CHRD), and SPARC (Osteonectin), cwcv and kazal-like domains proteoglycan 1 (SPOCK1) as candidate genes. Gene set enrichment analysis (GSEA) for these genes revealed Tβ4 and ARHGAP6 have a close association with the growth and development of SHF-DPCs. However, the expression of Tβ4 in the anagen was higher than that in the telogen, so we finally chose Tβ4 as the ultimate research object. Overexpressing Tβ4 promoted and silencing Tβ4 inhibited the proliferation of SHF-DPCs. These findings suggest that Tβ4 can promote the growth and development of SHF-DPCs and indicate that this molecule may be a valuable target for increasing cashmere production.

Human Derived Immortalized Dermal Papilla Cells With a Constant Expression of Testosterone Receptor

Androgenetic alopecia (AGA) is the most common type of hair loss, and is mainly caused by the biological effects of testosterone on dermal papilla cells (DPCs). In vitro culturing of DPCs might be a useful tool for the screening of target molecule of AGA. However, primary DPCs cannot continuously proliferate owing to cellular senescence and cell culture stress. In this study, we introduced mutant cyclin-dependent kinase 4 (CDK4), Cyclin D1, and telomerase reverse transcriptase (TERT) into DPCs. We confirmed protein expression of CDK4 and Cyclin D1, and enzymatic activity of TERT. Furthermore, we found the established cell line was free from cellular senescence. We also introduced the androgen receptor gene using a recombinant retrovirus, to compensate the transcriptional suppressed endogenous androgen receptor in the process of cell proliferation. Furthermore, we detected the efficient nuclear translocation of androgen receptor into the nucleus after the treatment of dihydrotestosterone, indicating the functionality of our introduced receptor. Our established cell line is a useful tool to identify the downstream signaling pathway, which activated by the testosterone.

Glucose metabolism regulates expression of hair-inductive genes of dermal papilla spheres via histone acetylation

Cellular metabolism is one of the crucial factors to regulate epigenetic landscape in various cells including immune cells, embryonic stem cells and hair follicle stem cells. Dermal papilla cells (DP) interact with epithelial stem cells to orchestrate hair formation. Here we show that active DP exhibit robust aerobic glycolysis. We observed decrease of signature genes associated with hair induction by DP in presence of low glucose (2 mM) and glycolysis inhibitors. Moreover, hair shaft elongation was attenuated by glycolysis inhibitors. Interestingly, excessive glucose is able to increase the expression of hair inductive genes and elongation of hair shaft. We also observed glycolysis-mediated histone acetylation is increased and chemical inhibition of acetyltransferase reduces expression of the signature genes associated with hair induction in active DP. These results suggest that glucose metabolism is required for expression of signature genes associated with hair induction. This finding may be beneficial for establishing and maintaining of active DP to generate hair follicle in vitro.

Murine dorsal hair type is genetically determined by polymorphisms in candidate genes that influence BMP and WNT signalling

Mouse dorsal coat hair types, guard, awl, auchene and zigzag, develop in three consecutive waves. To date, it is unclear if these hair types are determined genetically through expression of specific factors or can change based on their mesenchymal environment. We undertook a novel approach to this question by studying individual hair type in 67 Collaborative Cross (CC) mouse lines and found significant variation in the proportion of each type between strains. Variation in the proportion of zigzag, awl and auchene, but not guard hair, was largely due to germline genetic variation. We utilised this variation to map a quantitative trait locus (QTL) on chromosome 12 that appears to influence a decision point switch controlling the propensity for either second (awl and auchene) or third wave (zigzag) hairs to develop. This locus contains two strong candidates, Sostdc1 and Twist1, each of which carry several ENCODE regulatory variants, specific to the causal allele, that can influence gene expression, are expressed in the developing hair follicle, and have been previously reported to be involved in regulating human and murine hair behaviour, but not hair subtype determination. Both of these genes are likely to play a part in hair type determination via regulation of BMP and/or WNT signalling.

Assessment of Prolonged Dengue Virus Infection in Dermal Fibroblasts and Hair-Follicle Dermal Papilla Cells

Dengue virus (DENV)-mediated hair loss is one of the post-dengue fatigue syndromes and its pathophysiology remains unknown. Whether long-term or persistent infection with DENV in the scalp results in hair loss is unclear. In this study, we cultured human dermal fibroblasts (WS1 cells) and primary human hair-follicle dermal papilla cells (HFDPCs) in the long term with DENV-2 infection. The production of virion, the expression of inflammatory and anti-virus genes, and their signaling transduction activity in the infected cells were analyzed. DENV-2 NS3 protein and DENV-2 5′ UTR RNA were detected in fibroblasts and HFDPCs that were subjected to long-term infection with DENV-2 for 33 days. A significant amount of DENV-2 virion was produced by both WS1 cells and HFDPCs in the first two days of acute infection. The virion was also detected in WS1 cells that were infected in the long term, but HFDPCs failed to produce DENV-2 after long-term culture. Type I and type III interferons, and inflammatory cytokines were highly expressed in the acute phase of DENV infection in HFPDC and WS1 cells. However, in the long-term cultured cells, modest levels of anti-viral protein genes were expressed and we observed reduced signaling activity, which was correlated with the level of virus production changes. Long-term infection of DENV-2 downregulated the expression of hair growth regulatory factors, such as Rip1, Wnt1, and Wnt4. This in vitro study shows that the long-term infection with DENV-2 in dermal fibroblasts and dermal papilla cells may be involved with the prolonged-DENV-infection-mediated hair loss of post-dengue fatigue syndrome. However, direct evidence for viral replication in the human hair of a dengue victim or animal infection model is required.

Isolation, culture and growth characteristics of dermal papilla cells from Rex rabbits

Dermal papilla cells (DPCs) is the key dermal component of the hair follicle that directly regulates hair follicle development, growth and regeneration. Successfully isolated and cultured DPCs of Rex rabbit could provide a good model for the study of hair follicle development mechanism in vitro. Skin samples were collected from 30-day old Rex rabbits and separated by combination of Dispase II and Collagenase D, separation, culture, and purification of DPCs. The morphology of DPCs in vitro was observed and the growth curve was drawn, the number of DPCs presented progressive increase in a logarithmic model between the 4^th day and the 7^th day. The results of immune chemical and immune fluorescence shown that α smooth muscle actin (α-SMA) and versican were positive in cells. Growth character of the passages 3 (P3), P6, P9 and P12 DPCs were observed using MTT at 24 h, 48 h, 72 h, 96 h, 120 h and 144 h. The cell density of P12 was lower than P3 (P < 0.05); the flow cytometric analysis showed that DPCs at resting state/first gap (G0/G1) stage of P3 was higher than P12 (P < 0.05), and second gap/mitosis (G2/M) stage of P3 was lower than P12 (P < 0.05). However, the DPCs of P12 present triangular or short fusiform, retaining their unique aggregative growth characteristics. This results shown that the DPCs properties of P12 from Rex rabbits, still fit functional research in vitro. In conclusion, we successfully established the culturing condition of DPCs from Rex rabbits, and provide a material for studying the molecular mechanism of hair follicle development.

Cellular Nanofiber Structure with Secretory Activity-Promoting Characteristics for Multicellular Spheroid Formation and Hair Follicle Regeneration

Multicellular spheroids can mimic the in vivo microenvironment and maintain the unique functions of tissues, which has attracted great attention in tissue engineering. However, the traditional culture microenvironment with structural deficiencies complicates the culture and collection process and tends to lose the function of multicellular spheroids with the increase of cell passage. In order to construct efficient and functional multicellular spheroids, in this study, a chitosan/polyvinyl alcohol nanofiber sponge which has an open-cell cellular structure is obtained. The hair follicle (HF) regeneration model was employed to evaluate HF-inducing ability of dermal papilla (DP) multicellular spheroids which formed on the cellular structure nanofiber sponge. Through structural fine-tuning, the nanofiber sponge has appropriate elasticity for the creation of a three-dimensional dynamic microenvironment to regulate cellular behavior. The cellular structure nanofiber sponge tilts the balance of cell-substratum and cell-cell interactions to a state which is more conducive to the formation of controllable multicellular spheroids in a short time. More importantly, it improves the secretory activity of high-passaged dermal papilla cells and restores their intrinsic properties. Experiments using BALB/c nude mice show that cultured DP multicellular spheroids could effectively enhance HF-inducing ability. This novel system provides a simple and efficient strategy for multicellular spheroid formation and HF regeneration.

Pre-aggregation of scalp progenitor dermal and epidermal stem cells activates the WNT pathway and promotes hair follicle formation in in vitro and in vivo systems

BACKGROUND

Billions of dollars are invested annually by pharmaceutical companies in search of new options for treating hair loss conditions; nevertheless, the challenge remains. One major limitation to hair follicle research is the lack of effective and efficient drug screening systems using human cells. Organoids, three-dimensional in vitro structures derived from stem cells, provide new opportunities for studying organ development, tissue regeneration, and disease pathogenesis. The present study focuses on the formation of human hair follicle organoids.

METHODS

Scalp-derived dermal progenitor cells mixed with foreskin-derived epidermal stem cells at a 2:1 ratio aggregated in suspension to form hair follicle-like organoids, which were confirmed by immunostaining of hair follicle markers and by molecular dye labeling assays to analyze dermal and epidermal cell organization in those organoids. The hair-forming potential of organoids was examined using an in vivo transplantation assay.

RESULTS

Pre-aggregation of dermal and epidermal cells enhanced hair follicle formation in vivo. In vitro pre-aggregation initiated the interactions of epidermal and dermal progenitor cells resulting in activation of the WNT pathway and the formation of pear-shape structures, named type I aggregates. Cell-tracing analysis showed that the dermal and epidermal cells self-assembled into distinct epidermal and dermal compartments. Histologically, the type I aggregates expressed early hair follicle markers, suggesting the hair peg-like phase of hair follicle morphogenesis. The addition of recombinant WNT3a protein to the medium enhanced the formation of these aggregates, and the Wnt effect could be blocked by the WNT inhibitor, IWP2.

CONCLUSIONS

In summary, our system supports the rapid formation of a large number of hair follicle organoids (type I aggregates). This system provides a platform for studying epithelial-mesenchymal interactions, for assessing inductive hair stem cells and for screening compounds that support hair follicle regeneration.

Expression profile analysis of dermal papilla cells mRNA in response to WNT10B treatment

Dermal papilla cells (DPCs) are associated with the development of hair follicles (HFs) and the regulation of the hair growth cycle. Previous studies have shown that Wnt family member 10B (WNT10B) plays an important role in the proliferation and survival of DPCs in vitro, and promotes the growth of HFs. However, the underlying mechanisms have not been fully elucidated. The present study evaluated the role of WNT10B in regulating HF morphogenesis by characterizing the differential gene expression profiles between WNT10B-treated DPCs and control DPCs using RNA-sequencing (RNA-seq). A total of 1,073 and 451 genes were upregulated and downregulated, respectively. The RNA-seq data was subsequently validated by reverse-transcription quantitative PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that 442 GO terms and 21 KEGG pathways were significantly enriched. Further functional analysis revealed that WNT10B decreased translation initiation, elongation and termination, and RNA metabolic processes in cultured DPCs compared with controls in vitro. Human signaling networks were compared using pathway analysis, and treatment of DPCs with WNT10B was revealed to downregulate the ribosome biogenesis pathway and decrease protein synthesis in vitro. KEGG pathway analysis showed that WNT10B upregulated the phosphoinositide 3-kinase/protein kinase B signaling pathway. The present study analyzed the expression of mRNA in WNT10B-treated DPCs using next-generation sequencing and uncovered mechanisms regulating the induction of HFs.

Ectodysplasin-A2 induces apoptosis in cultured human hair follicle cells and promotes regression of hair follicles in mice

Ectodysplasin is a ligand of the TNF family that plays a key role in ectodermal differentiation. EDA-A1 and EDA-A2 are two isoforms of ectodysplasin that differ only by the insertion of two amino acids and bind to two different receptors, ectodysplasin A receptor (EDAR) and ectodysplasin A2 receptor (EDA2R), respectively. Mutations of EDA-A1 and its receptor EDAR have been associated with hypohidrotic ecodermal dysplasia (HED). However, the role of EDA-A2 and the expression pattern of EDA2R in human hair follicles and in the mouse hair growth cycle have not been reported. In this study, we first investigated the expression of EDA2R in human hair follicles and in cultured follicular cells. EDA2R was strongly expressed in outer root sheath (ORS) cells and weakly expressed in dermal papilla (DP) cells. EDA-A2 induced the apoptosis of both ORS cells and DP cells via the activation of cleaved caspase-3. In addition, EDA2R was highly expressed in the late anagen phase compared with other phases in the hair growth cycle. Moreover, EDA-A2 induced apoptosis in cultured human hair follicle cells and in the mouse hair growth cycle, causing the premature onset of the catagen phase. Collectively, our results suggest that EDA-A2/EDA2R signaling could inhibit hair growth, and an inhibitor of EDA-A2/EDA2R signaling may be a promising agent for the treatment and prevention of hair loss.

Preliminary study on microR-148a and microR-10a in dermal papilla cells of Hu sheep

Background

Hu sheep, a unique Chinese breed with high reproductive performance, are also well known for their rare white lambskin in China. The quality of lambskin is affected by hair follicles, and dermal papilla cells are an important component of hair follicles that plays a key role in hair follicle growth and development. This study helps elucidate the effect of miR-148a and miR-10a on hair follicle growth and development.

Results

Based on the results of gene chip and high-throughput sequencing, bone morphogenetic protein 7 (BMP7) was used as a research object. Bioinformatics analysis and the dual-luciferase reporter system indicated that, along with Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) that miR-148a and miR-10a target relationships with BMP7. BMP7 was the target gene both for miR-148a and miR-10a by the dual-luciferase reporter system and Western blot. Hu sheep dermal papilla cells were successfully isolated and purified, and after transfecting miR-148a/miR-10a mimics and inhibitors into dermal papilla cells, a Cell Counting Kit-8 (CCK-8) was used to determine that miR-148a/miR-10a inhibited the proliferation of Hu sheep dermal papilla cells. In addition, after the overexpression of miR-148a, the expression levels of Smad3 (P < 0.05), Smad6 (P < 0.05), Smad4 (P < 0.01), and Smad5 (P < 0.01) were significantly higher than those of the control groups. After the inhibition of miR-148a, the expression levels of Smad3 (P < 0.05), Smad4 (P < 0.05), and TGF-β (P < 0.01) were significantly lower than those of the control groups. After the overexpression of miR-10a, the expression levels of Smad1 (P < 0.01), Smad2 (P < 0.05), Smad4 (P < 0.01), Smad5 (P < 0.01), and TGF-β (P < 0.05) were significantly lower than those of the control groups. After the inhibition of miR-10a, the expression levels of Smad1 (P < 0.01) and Smad2 (P < 0.05) were significantly lower than those of the control groups.

Conclusions

These results revealed the target relationship between miR-148a, miR-10a and BMP7, and the effect of miR-148a and miR-10a on the proliferation of dermal papilla cells. They will provide the basis for a follow-up study on how miR-148a, and miR-10a mediate BMP7 regulation of hair follicle growth and development.

Use of extracellular matrix hydrogel from human placenta to restore hair-inductive potential of dermal papilla cells

Aim: To explore the feasibility of human placenta extracellular matrix (HPECM) hydrogel in restoring the hair-inductive capacity of high-passaged (P8) dermal papilla cells (DPCs) for hair follicle regeneration. Materials & methods: HPECM hydrogel was prepared following decellularization and enzymatic solubilization treatment. DPCs isolated from human scalp were cultured in 2D and 3D environments. The hair-inductive ability of DPCs was assessed by quantitative RT-PCR, immunofluorescence staining, immunoblotting and patch assay. Results: DPCs (P8) formed spheres when cultured on the HPECM hydrogel. The expression levels of Versican, ALP, and β-catenin were restored in the DP spheres. HPECM hydrogel-cultured DP spheres co-grafted with newborn mouse epidermal cells regenerated new hair follicle. Conclusion: HPECM hydrogel successfully restores the hair-inductive capacity of high-passaged DPCs.

CRISPR/Cas9-mediated VDR knockout plays an essential role in the growth of dermal papilla cells through enhanced relative genes

Background

Hair follicles in cashmere goats are divided into primary and secondary hair follicles (HFs). HF development, which determines the morphological structure, is regulated by a large number of vital genes; however, the key functional genes and their interaction networks are still unclear. Although the vitamin D receptor (VDR) is related to cashmere goat HF formation, its precise effects are largely unknown. In the present study, we verified the functions of key genes identified in previous studies using hair dermal papilla (DP) cells as an experimental model. Furthermore, we used CRISPR/Cas9 technology to modify the VDR in DP cells to dissect the molecular mechanism underlying HF formation in cashmere goats.

Results

The VDR expression levels in nine tissues of Shaanbei white cashmere goats differed significantly between embryonic day 60 (E60) and embryonic day 120 (E120). At E120, VDR expression was highest in the skin. At the newborn and E120 stages, the VDR protein was highly expressed in the root sheath and hair ball region of Shaanbei cashmere goats. We cloned the complete CDS of VDR in the Shaanbei white cashmere goat and constructed a VDR-deficient DP cell model by CRISPR/Cas9. Heterozygous and homozygous mutant DP cells were produced. The growth rate of mutant DP cells was significantly lower than that of wild-type DP cells (P < 0.05) and VDR mRNA levels in DP cells decreased significantly after VDR knockdown (P < 0.05). Further, the expression levels of VGF, Noggin, Lef1, and β-catenin were significantly downregulated (P < 0.05).

Conclusions

Our results indicated that VDR has a vital role in DP cells, and that its effects are mediated by Wnt and BMP4 signaling.

Induction of hair follicle neogenesis with cultured mouse dermal papilla cells in de novo regenerated skin tissues

De novo skin regeneration with human keratinocytes amplified in culture is a life-saving procedure for patients with extensive skin loss and chronic wounds. It also provides a valuable platform for gene function and therapeutic assessments. Nevertheless, tissues generated in this manner lack hair follicles that are important for skin homeostasis, barrier function, and repair. In this study, we generated skin tissues with human keratinocytes combined with dermal papilla (DP) cells isolated from mouse whisker hair. For this, cultured keratinocytes and mouse DP (mDP) cells were mixed at 10:1 ratio and seeded onto devitalized human dermal matrix derived from surgically discarded human abdominoplasty skin. After 1 week in submerged culture, the cell/matrix composites were grafted onto the skin wound beds of immunocompromised NSG.SCID mice. Histological analysis of 6-week-old skin grafts showed that tissues generated with the addition of mDP cells contained Sox2-positive dermal condensates and well-differentiated folliculoid structures that express human keratinocyte markers. These results indicate that cultured mDP cells can induce hair follicle neogenesis in the de novo regenerated skin tissues. Our method offers a new experimental system for mechanistic studies of hair follicle morphogenesis and tissue regeneration and provides insights to solving an important clinical challenge in generation of fully functional skin with a limited source of donor cells.

Gene Expression Analysis of Chondrogenic Markers in Hair Follicle Dermal Papillae Cells Under the Effect of Laser Photobiomodulation and the Synovial Fluid

Introduction: Regarding the limited ability of the damaged cartilage cells to self-renew, which is due to their specific tissue structure, subtle damages can usually cause diseases such as osteoarthritis. In this work, using laser photobiomodulation and an interesting source of growth factors cocktail called the synovial fluid, we analyzed the chondrogenic marker genes in treated hair follicle dermal papilla cells as an accessible source of cells with relatively high differentiation potential. Methods: Dermal papilla cells were isolated from rat whisker hair follicle (Rattus norvegicus) and established cell cultures were treated with a laser (gallium aluminum arsenide diode Laser (λ=780 nm, 30 mW) at 5 J/cm² ), the synovial fluid, and a combination of both. After 1, 4, 7, and 14 days, the morphological changes were evaluated and the expression levels of four chondrocyte marker genes (Col2a1, Sox-9, Col10a1, and Runx-2) were assessed by the quantitative real-time polymerase chain reaction. Results: It was monitored that treating cells with laser irradiation can accelerate the rate of proliferation of cells. The morphology of the cells treated with the synovial fluid altered considerably as in the fourth day they surprisingly looked like cultured articular chondrocytes. The gene expression analysis showed that all genes were up-regulated until the day 14 following the treatments although not equally in all the cell groups. Moreover, the cell groups treated with both irradiation and the synovial fluid had a significantly augmented expression in gene markers. Conclusion: Based on the gene expression levels and the morphological changes, we concluded that the synovial fluid can have the potential to make the dermal papilla cells to most likely mimic the chondrogenic and/or osteogenic differentiation, although this process seems to be augmented by the irradiation of the low-level laser.

Functional anatomy of the hair follicle: The Secondary Hair Germ

The secondary hair germ (SHG)-a transitory structure in the lower portion of the mouse telogen hair follicle (HF)-is directly involved in anagen induction and eventual HF regrowth. Some crucial aspects of SHG functioning and ontogenetic relations with other HF parts, however, remain undefined. According to recent evidence (in contrast to previous bulge-centric views), the SHG is the primary target of anagen-inducing signalling and a source of both the outer root sheath (ORS) and ascending HF layers during the initial (morphogenetic) anagen subphase. The SHG is comprised of two functionally distinct cell populations. Its lower portion (originating from lower HF cells that survived catagen) forms all ascending HF layers, while the upper SHG (formed by bulge-derived cells) builds up the ORS. The predetermination of SHG cells to a specific morphogenetic fate contradicts their attribution to the "stem cell" category and supports SHG designation as a "germinative" or a "founder" cell population. The mechanisms of this predetermination driving transition of the SHG from "refractory" to the "competent" state during the telogen remain unknown. Functionally, the SHG serves as a barrier, protecting the quiescent bulge stem cell niche from the extensive follicular papilla/SHG signalling milieu. The formation of the SHG is a prerequisite for efficient "precommitment" of these cells and provides for easier sensing and a faster response to anagen-inducing signals. In general, the formation of the SHG is an evolutionary adaptation, which allowed the ancestors of modern Muridae to acquire a specific, highly synchronized pattern of hair cycling.

The Wave complex controls epidermal morphogenesis and proliferation by suppressing Wnt-Sox9 signaling

The Wave complex promotes Arp2/3-mediated actin polymerization. Cohen et al. show that Wave complex activity regulates epidermal shape and growth. Without Wave complex activity, F-actin content is down-regulated and ectopic activity of the Wnt/β-catenin–SOX9 pathway is triggered. This activity induces epidermal hyperproliferation and disrupts tissue architecture.

Development of the skin epidermis requires tight spatiotemporal control over the activity of several signaling pathways; however, the mechanisms that orchestrate these events remain poorly understood. Here, we identify a key role for the Wave complex proteins ABI1 and Wave2 in regulating signals that control epidermal shape and growth. In utero RNAi-mediated silencing of Abi1 or Wasf2 induced cellular hyperproliferation and defects in architecture of the interfollicular epidermis (IFE) and delayed hair follicle growth. Unexpectedly, SOX9, a hair follicle growth regulator, was aberrantly expressed throughout the IFE of the mutant embryos, and its forced overexpression mimicked the Wave complex loss-of-function phenotype. Moreover, Wnt signaling, which regulates SOX9⁺ cell specification, was up-regulated in Wave complex loss-of-function IFE. Importantly, we show that the Wave complex regulates filamentous actin content and that a decrease in actin levels is sufficient to elevate Wnt/β-catenin signaling. Our results identify a novel role for Wave complex– and actin-regulated signaling via Wnt and SOX9 in skin development.

TSA restores hair follicle-inductive capacity of skin-derived precursors

The genesis of the hair follicle relies on signals derived from mesenchymal cells in the dermis during skin morphogenesis and regeneration. Multipotent skin-derived precursors (SKPs), which exhibit long term proliferation potential when being cultured in spheroids, have been shown to induce hair genesis and hair follicle regeneration in mice, implying a therapeutic potential of SKPs in hair follicle regeneration and bioengineering. However, the hair-inductive property of SKPs declines progressively upon ex vivo culture expansion, suggesting that the expressions of the genes responsible for hair induction are epigenetically unstable. In this study, we found that TSA markedly alleviated culture expansion induced SKP senescence, increased the expression and activity of alkaline phosphatase (AP) in the cells and importantly restored the hair inductive capacity of SKPs. TSA increased the acetylation level of histone H3, including the K19/14 sites in the promoter regions of bone morphogenetic proteins (BMPs) genes, which were associated with elevated gene expression and BMP signaling activity, suggesting a potential attribution of BMP pathway in TSA induced recovery of the hair inductive capacity of SKPs.

LncRNA-000133 from secondary hair follicle of Cashmere goat: identification, regulatory network and its effects on inductive property of dermal papilla cells

Long noncoding RNAs (lncRNAs), a class of non-protein conding RNAs > 200 nt in length, were thought to play critical roles in regulating the expression of protein-coding genes. Here, we identified and characterized a novel lncRNA-000133 from the secondary hair follicle (SHF) of cashmere goat with its ceRNA network analysis, as well as, its potential effects on inductive property of dermal papilla cells were evaluated through overexpression analysis. Expression analysis indicated that lncRNA-000133 had a significantly higher expression at anagen than that at telogen in SHF of Cashmere goat, suggesting that lncRNA-000133 might be involved in the reconstruction of SHF with the formation and growth of cashmere fiber. Taken together with methylation analysis, we showed that 5' regulatory region methylation of the lncRNA-000133 gene might be involved in its expression suppression in SHF of Cashmere goat. The ceRNA regulatory network showed that a rich and complex regulatory relationship between lncRNA-000133 and related miRNAs with their target genes. The overexpression of lncRNA-000133 led to a significant increasing in the relative expression of ET-1, SCF, ALP and LEF1 in dermal papilla cells suggesting that lncRNA-000133 appears to contribute the inductive property of dermal papilla cells.

Mesenchymal stromal cells-exosomes: a promising cell-free therapeutic tool for wound healing and cutaneous regeneration

Cutaneous regeneration at the wound site involves several intricate and dynamic processes which require a series of coordinated interactions implicating various cell types, growth factors, extracellular matrix (ECM), nerves, and blood vessels. Mesenchymal stromal cells (MSCs) take part in all the skin wound healing stages playing active and beneficial roles in animal models and humans. Exosomes, which are among the key products MSCs release, mimic the effects of parental MSCs. They can shuttle various effector proteins, messenger RNA (mRNA) and microRNAs (miRNAs) to modulate the activity of recipient cells, playing important roles in wound healing. Moreover, using exosomes avoids many risks associated with cell transplantation. Therefore, as a novel type of cell-free therapy, MSC-exosome -mediated administration may be safer and more efficient than whole cell. In this review, we provide a comprehensive understanding of the latest studies and observations on the role of MSC-exosome therapy in wound healing and cutaneous regeneration. In addition, we address the hypothesis of MSCs microenvironment extracellular vesicles (MSCs-MEVs) or MSCs microenvironment exosomes (MSCs-MExos) that need to take stock of and solved urgently in the related research about MSC-exosomes therapeutic applications. This review can inspire investigators to explore new research directions of MSC-exosome therapy in cutaneous repair and regeneration.