Role In Hair Follicle Development Research Articles

MiR-199a-3p Regulates the PTPRF/β-Catenin Axis in Hair Follicle Development: Insights into the Pathogenic Mechanism of Alopecia Areata.

Alopecia areata is an autoimmune disease characterized by the immune system attacking self hair follicles, mainly in the scalp. There is no complete cure, and the pathogenesis is still not fully understood. Here, sequencing of skin tissues collected from 1-month-old coarse- and fine-wool lambs identified miR-199a-3p as the only small RNA significantly overexpressed in the fine-wool group, suggesting a role in hair follicle development. MiR-199a-3p expression was concentrated in the dermal papillae cells of sheep hair follicles, along with enhanced β-catenin expression and the inhibition of PTPRF protein expression. We also successfully constructed a mouse model of alopecia areata by intracutaneous injection with an miR-199a-3p antagomir. Injection of the miR-199a-3p agomir resulted in hair growth and earlier anagen entry. Conversely, local injection with the miR-199a-3p antagomir resulted in suppressed hair growth at the injection site, upregulation of immune system-related genes, and downregulation of hair follicle development-related genes. In vivo and in vitro analyses demonstrated that miR-199a-3p regulates hair follicle development through the PTPRF/β-catenin axis. In conclusion, a mouse model of alopecia areata was successfully established by downregulation of a small RNA, suggesting the potential value of miR-199a-3p in the study of alopecia diseases. The regulatory role of miR-199a-3p in the PTPRF/β-catenin axis was confirmed, further demonstrating the link between alopecia areata and the Wnt-signaling pathway.

Hypoxia inducible factor-1α promotes trichogenic gene expression in human dermal papilla cells

Dermal papilla cells (DPCs) play critical roles in hair follicle development, but the underlying mechanisms that contribute to hair regeneration have yet to be fully elucidated, particularly in terms of alterations in androgenetic alopecia patients. In this study, we demonstrated that hypoxia-inducible factor-1α (HIF-1α) is suppressed in scalp tissues of androgenetic alopecia patients and potentially associated with hair follicle development. Using RT-qPCR and western blot, we found that mRNA and protein levels of trichogenic genes, LEF1 and versican (VCAN), were attenuated in HIF-1α knockdown DPCs. Under an in vivo mimicked environment in a three-dimensional spheroid culture, HIF-1α-suppressed DPCs downregulated the expression of hair induction-related genes. Finally, treatment with a HIF-1α activator resulted in the elevated expression of trichogenic genes in DPCs. This study highlights the importance of dermal HIF-1α expression in regulating trichogenic genes and provides a promising therapeutic target and a fundamental tissue engineering approach for hair loss treatment.

Skin-specific transgenic overexpression of ovine β-catenin in mice.

β-catenin is a conserved molecule that plays an important role in hair follicle development. In this study, we generated skin-specific overexpression of ovine β-catenin in transgenic mice by pronuclear microinjection. Results of polymerase chain reaction (PCR) testing and Southern blot showed that the ovine β-catenin gene was successfully transferred into mice, and the exogenous β-catenin gene was passed down from the first to sixth generations. Furthermore, real-time fluorescent quantitative PCR (qRT-PCR) and western blot analysis showed that β-catenin mRNA was specifically expressed in the skin of transgenic mice. The analysis of F6 phenotypes showed that overexpression of β-catenin could increase hair follicle density by prematurely promoting the catagen-to-anagen transition. The results showed that ovine β-catenin could also promote hair follicle development in mice. We, therefore, demonstrate domestication traits in animals.

The Molecular Mechanism of Natural Products Activating Wnt/β-Catenin Signaling Pathway for Improving Hair Loss.

Hair loss, or alopecia, is a dermatological disorder that causes psychological stress and poor quality of life. Drug-based therapeutics such as finasteride and minoxidil have been clinically used to treat hair loss, but they have limitations due to their several side effects in patients. To solve this problem, there has been meaningful progress in elucidating the molecular mechanisms of hair growth and finding novel targets to develop therapeutics to treat it. Among various signaling pathways, Wnt/β-catenin plays an essential role in hair follicle development, the hair cycle, and regeneration. Thus, much research has demonstrated that various natural products worldwide promote hair growth by stimulating Wnt/β-catenin signaling. This review discusses the functional role of the Wnt/β-catenin pathway and its related signaling molecules. We also review the molecular mechanism of the natural products or compounds that activate Wnt/β-catenin signaling and provide insights into developing therapeutics or cosmeceuticals that treat hair loss.

Expression profile of long non-coding RNA in inner Mongolian cashmere goat with putative roles in hair follicles development.

The hair follicle is a complex skin accessory organ, which determines hair growth. Long non-coding RNAs (lncRNAs) have been proven to play an important role in hair follicle development, but their specific mechanism is still unclear. In this study, high-throughput sequencing was used to obtain the expression profiles of lncRNA in the hair follicles of Inner Mongolian cashmere goats at different embryonic stages (45, 55, 65, and 75 days), and a total of 6,630 lncRNA were identified. According to the rules of hair follicle development, we combined miRNA and mRNA databases (published) and predicted lncRNA-miRNA, miRNA-mRNA, and lncRNA-mRNA interaction pairs in the 45 vs. 75 comparison group. We obtained 516 lncRNA-mRNA, 1,011 lncRNA-miRNA, and 7,411 miRNA-mRNA relationship pairs. Finally, target genes were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and it was found that they were mainly enriched in the Wnt signaling pathway and PI3K-Akt signaling pathway related to hair follicle development, indicating that lncRNA may interact with miRNA/mRNA to directly or indirectly regulate the expression of genes related to hair follicle development. Dual-luciferase reporter gene analysis showed that lncRNA MSTRG.1705.1 could bind to Chi-miR-1, while lncRNA MSTRG.11809.1 had no binding site for Chi-miR-433. In conclusion, this study aims to further analyze the molecular regulation mechanism of hair follicle development and to lay a theoretical foundation for revealing the regulation mechanism of cashmere hair follicle growth.

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

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

Characterization and functional analysis of SMAD2 regulation in hair follicle cycle in Angora rabbits.

Hair follicle (HF) development is characterized by periodic growth cycles regulated by numerous factors. We previously showed that SMAD2 might be involved in the HF growth cycle in Angora rabbits. However, its extra role in the HF growth and development remains obscure. In this study, we cloned the complete coding sequence (CDS) of the Angora rabbit SMAD2 gene. Within SMAD2 CDS, we identified the open reading frame (ORF) had a length of 1314bp and encoding 437 amino acids. Bioinformatics analyses revealed that the SMAD2 protein is unstable and hydrophilic, and predominatelylocalizesin the cell nucleus. We identified that SMAD2 expression was elevated in the telogen phase of the during HF cycle. The knockdown and overexpression of SMAD2 could regulate HF growth and development related genes, such as WNT2, FGF2, and LEF1.Furthermore, SMAD2 may upregulate TGF-β signaling pathway-related genes, including TFDP1, E2F4, and RBL1. In conclusion, our results indicate that SMAD2 plays a vital role in HF development by regulating the TGF-β signaling pathway.

786 A master regulator function of hairless in skin homeostasis and immune regulation

The hairless (Hr) gene plays an essential role in hair follicle development and skin homeostasis. Both humans and mice lacking hairless activity suffer from complete hair loss and abnormal epidermal proliferation and differentiation, although the mechanisms underlying such developmental defects remain largely unknown. We recently demonstrated that Hr encodes a histone demethylase and acts as an epigenetic regulator of the expression of its target genes. Gene expression profiling studies identified pro-inflammatory IL-1 family cytokines, including IL-36 and IL-1β, among the major targets of Hr.

MAD2B acts as a negative regulatory partner of TCF4 on proliferation in human dermal papilla cells

Dermal papilla cells (DPCs) are important components of hair follicles and play a critical role in hair follicle development. However, the mechanisms by which DPCs induce hair follicle development remain unclear. In the present study, we identified the mitotic arrest deficient protein MAD2B as a modifier of DPCs. Overexpression of MAD2B inhibited DPC aggregative growth and proliferation induced by the Wnt signaling activator T cell factor 4 (TCF4), and decreased TCF4-induced expression and the release of hair growth-related cytokines, including hepatocyte growth factor, insulin-like growth factor-1, and vascular endothelial growth factor in DPCs. In contrast, knockdown of MAD2B promoted TCF4-induced DPC proliferation, but did not affect the expression and secretion of cytokines by TCF4-induced DPCs. These results suggest a functional antagonism between MAD2B and TCF4 in DPC-induced hair follicle development. Mechanistically, MAD2B physically interacted with TCF4 to repress TCF4 transcriptional activity via β-catenin mediation, leading to reduced β-catenin/TCF4-dependent transactivation and Wnt signaling activity. These results demonstrate, for the first time, that MAD2B plays a negative role in TCF4-induced DPC growth and proliferation.

Peculiarities and pitfalls of quantifying mitochondrial energy metabolism in the skin.

Peculiarities and pitfalls of quantifying mitochondrial energy metabolism in the skin.

Hair-growth Promoting Effect of Microneedle Roller Therapy

Micro needle roller therapy has been used for cosmetic purposes, such as reducing skin winkles and improving elasticity of skin. It is claimed that micro needle roller therapy has potentials for connective tissue regeneration by facilitating collagen synthesis. Therefore, there seems to be a possibility that connective tissue regenerating potential of micro needle roller therapy could influence the hair growth cycle. This study, we investigated the hair growth-promoting effects of micro needle roller therapy. C57BL/6 mice were devided into three groups as follows: normal saline-treated, minoxidil-treated, and micro needle roller therapy-received group. Hair growth activity was evaluated by handscopic and microscopic observations. Sections of dorsal skin were stained with hematoxylin and eosin. Expression of BrdU, FGF, and VEGF was detected by immunohistochemical staining. Micro needle roller therapy enhanced the development of hair follicle during anagen. Immunohistochemical analysis revealed that micro neeld roller therapy incresed the expression of BrdU and FGF in the hair follicles of C57BL/6 mice. Furthermore, micro needle roller therapy upregulated mRNA expression of VEGFR-2, FGF-2, EGF ?growth factors that play a central role in hair follicle development during anagen. These results suggest that Micro needle roller therapy can potentially be used for the treatment of alopecia.

EGFR-Ras-Raf Signaling in Epidermal Stem Cells: Roles in Hair Follicle Development, Regeneration, Tissue Remodeling and Epidermal Cancers

The mammalian skin is the largest organ of the body and its outermost layer, the epidermis, undergoes dynamic lifetime renewal through the activity of somatic stem cell populations. The EGFR-Ras-Raf pathway has a well-described role in skin development and tumor formation. While research mainly focuses on its role in cutaneous tumor initiation and maintenance, much less is known about Ras signaling in the epidermal stem cells, which are the main targets of skin carcinogenesis. In this review, we briefly discuss the properties of the epidermal stem cells and review the role of EGFR-Ras-Raf signaling in keratinocyte stem cells during homeostatic and pathological conditions.

Genome-wide landscapes of human local adaptation in Asia.

Genetic studies of human local adaptation have been facilitated greatly by recent advances in high-throughput genotyping and sequencing technologies. However, few studies have investigated local adaptation in Asian populations on a genome-wide scale and with a high geographic resolution. In this study, taking advantage of the dense population coverage in Southeast Asia, which is the part of the world least studied in term of natural selection, we depicted genome-wide landscapes of local adaptations in 63 Asian populations representing the majority of linguistic and ethnic groups in Asia. Using genome-wide data analysis, we discovered many genes showing signs of local adaptation or natural selection. Notable examples, such as FOXQ1, MAST2, and CDH4, were found to play a role in hair follicle development and human cancer, signal transduction, and tumor repression, respectively. These showed strong indications of natural selection in Philippine Negritos, a group of aboriginal hunter-gatherers living in the Philippines. MTTP, which has associations with metabolic syndrome, body mass index, and insulin regulation, showed a strong signature of selection in Southeast Asians, including Indonesians. Functional annotation analysis revealed that genes and genetic variants underlying natural selections were generally enriched in the functional category of alternative splicing. Specifically, many genes showing significant difference with respect to allele frequency between northern and southern Asian populations were found to be associated with human height and growth and various immune pathways. In summary, this study contributes to the overall understanding of human local adaptation in Asia and has identified both known and novel signatures of natural selection in the human genome.

Cloning and expression in follicle anagen of &lt;I&gt;ILK&lt;/I&gt; gene in sheep

Integrin linked kinase (ILK) is a scaffold protein, which plays important roles in hair follicle development. The cDNA sequence of novel ILK gene in sheep was cloned by PCR method and analyzed by bioinformatics. Tissue expression profiling in eight tissues and temporal profiling at different wool follicle anagen stages in skin was analyzed. The results showed that the whole open reading frame (ORF) of ILK gene was 1 359 bp in length, which encoded 452 amino acids. Bioinformatic analysis indicated that the secondary structure of ILK gene was mainly made up of three ankyrin repeats and a kinase domain, and there were multiple phosphorylation and Protein Kinase C sites in this gene. The RT-PCR result confirmed that ILK mRNA was expressed in heart, liver, spleen, lung, skeletal muscle, skin, and small intestine, and the expression level was much higher in skin, spleen, and liver than others. The q-PCR analysis demonstrated that the ex-pression level of ILK was significantly increased from March to May (early follicle anagen initiation) in both sheep breeds, Chinese Merino and Kazakh sheep, and there were certain differences from June to October between the two breeds. The above results indicated that ILK gene may play key roles in regulating secondary follicle growth.

Expression of mineralized tissue associated proteins: Dentin sialoprotein and phosphophoryn in rodent hair follicles

Mammalian hair development and tooth development are controlled by a series of reciprocal epithelial-mesenchymal interactions. Similar growth factors and transcription factors, such as fibroblast growth factor (FGF), sonic hedgehog homolog (SHH), bone morphogenetic proteins (BMPs) and Wnt10a, were reported to be involved in both of these interactions. Dentin sialoprotein (DSP) and phosphophoryn (PP) are the two major non-collagenous proteins secreted by odontoblasts that participate in dentin mineralization during tooth development. Because of striking similarities between tooth development and hair follicle development, we investigated whether DSP and/or PP proteins may also play a role in hair follicle development. In this study, we examined the presence and location of DSP/PP proteins during hair follicle development. Rat PP proteins were detected using immunohistochemical/immunofluorescent staining. DSP-PP mRNAs were detected by in situ hybridization with riboprobes. LacZ expression was detected in mouse tissues using a DSP-PP promoter-driven LUC in transgenic mice. We found that PP proteins and DSP-PP mRNAs are present in rat hair follicles. We also demonstrate that an 8 kb DSP-PP promoter is able to drive lacZ expression in hair follicles. We have firmly established the presence of DSP/PP in mouse and rat hair follicles by immunohistochemical/immunofluorescent staining, in situ hybridization with riboprobes and transgenic mice studies. The expression of DSP/PP in hair follicles is the first demonstration that major mineralization proteins likely may also contribute to soft tissue development. This finding opens a new avenue for future investigations into the molecular-genetic management of soft tissue development.

Expression of a Constitutively Active Calcineurin Encoded by an Intron-Retaining mRNA in Follicular Keratinocytes

Hair growth is a highly regulated cyclical process. Immunosuppressive immunophilin ligands such as cyclosporin A (CsA) and FK506 are known as potent hair growth modulatory agents in rodents and humans that induce active hair growth and inhibit hair follicle regression. The immunosuppressive effectiveness of these drugs has been generally attributed to inhibition of T cell activation through well-characterized pathways. Specifically, CsA and FK506 bind to intracellular proteins, principally cyclophilin A and FKBP12, respectively, and thereby inhibit the phosphatase calcineurin (Cn). The calcineurin (Cn)/NFAT pathway has an important, but poorly understood, role in the regulation of hair follicle development. Here we show that a novel-splicing variant of calcineurin Aß CnAß-FK, which is encoded by an intron-retaining mRNA and is deficient in the autoinhibitory domain, is predominantly expressed in mature follicular keratinocytes but not in the proliferating keratinocytes of rodents. CnAß-FK was weakly sensitive to Ca2+ and dephosphorylated NFATc2 under low Ca2+ levels in keratinocytes. Inhibition of Cn/NFAT induced hair growth in nude mice. Cyclin G2 was identified as a novel target of the Cn/NFATc2 pathway and its expression in follicular keratinocytes was reduced by inhibition of Cn/NFAT. Overexpression of cyclin G2 arrested the cell cycle in follicular keratinocytes in vitro and the Cn inhibitor, cyclosporin A, inhibited nuclear localization of NFATc2, resulting in decreased cyclin G2 expression in follicular keratinocytes of rats in vivo. We therefore suggest that the calcineurin/NFAT pathway has a unique regulatory role in hair follicle development.

Sox9 Increases the Proliferation and Colony-forming Activity of Outer Root Sheath Cells CulturedIn Vitro

β-catenin plays a pivotal role in hair follicle development and hair growth cycle. The aim of this study was to identify β-catenin-regulated genes in cultured human hair outer root sheath (ORS) cells. Primary cultured ORS cells were transduced with recombinant adenovirus expressing N-terminal truncated β-catenin (constitutive active form), and β-catenin-regulated genes were identified. Overexpression of the constitutively active form of β-catenin led to induction of Sox9 expression at both mRNA and protein levels. To investigate the potential role of Sox9, we made the recombinant adenovirus expressing green fluorescent protein-tagged Sox9, and then transduced into cultured ORS cells. Interestingly, Sox9 induced the expression of keratin 15, increased the proliferation of ORS cells in vitro, and enhanced colony-forming activity. Our results suggest that Sox9 is a β-catenin-regulated gene in ORS cells, and has potential importance in the regulation of hair follicle homeostasis.

Chemokines as targets of Eda – —A role in hair follicle development?

Chemokines as targets of Eda – —A role in hair follicle development?

Akt2 and SGK3 are both determinants of postnatal hair follicle development

SGK3, which previously has been shown to play a key role in hair follicle development in mice, is a member of the AGC family of serine-threonine kinases. Mice lacking SGK3 have abnormal follicle cycling, which begins shortly after birth and ameliorates substantially with age. However, this developmental abnormality is not recapitulated in mice lacking closely related kinases Akt1, Akt2, or Akt3. To examine whether Akt2 interacts with SGK3 in postnatal hair development, we have generated and characterized Akt2/SGK3 double knockouts (DKOs). We find that the DKO mice have a defect in hair growth that is markedly worse than that of SGK3(-/-) mice and does not ameliorate with age. Morphologically, this defect is characterized by accelerated entry into catagen and through anagen, irregular hair follicle orientation, and increased expression of sebaceous glands. The defect is preceded by a profound failure to increase follicle matrix cell nuclear beta-catenin accumulation and proliferation at the onset of morphogenesis. Furthermore, in cultured keratinocytes, transfected Akt2 and SGK3 both stimulate transcription of a beta-catenin-LEF1-dependent reporter gene. Thus, SGK3 and Akt2 both appear to play important roles in postnatal hair follicle morphogenesis, likely because of their redundant regulation of beta-catenin-dependent transcriptional processes, which control hair follicle cell proliferation.

Pitx2, a β-catenin-regulated transcription factor, regulates the differentiation of outer root sheath cells cultured in vitro

Beta-catenin exerts its crucial role in hair follicle development and hair growth cycle. Although the importance of Wnt/beta-catenin is well recognized, the downstream effectors of beta-catenin have not been clearly elucidated yet. The aim of this study is to identify the beta-catenin-regulated genes in cultured human hair outer root sheath (ORS) cells. We transduced ORS cells with adenovirus harboring the expression cassette for constitutive active form of beta-catenin, then performed cDNA microarray. Overexpression of beta-catenin led to the upregulation of hair cell differentiation markers such as keratin 16 and 17. In addition, the expression of Pitx2, a bicoid-type homeodomain transcription factor, was also increased by overexpression of beta-catenin in ORS cells cultured in vitro. To investigate the potential role of Pitx2, we made the recombinant adenovirus expressing Pitx2, then transduced into the cultured ORS cells. Interestingly, Pitx2 induced the expression of keratin 16 and 17, indicating that Pitx2 activates ORS cells towards the follicular differentiation pathway preferentially. Our results implicate the potential importance of Pitx2 as a beta-catenin downstream modulator in hair growth control.