Secondary Hair Research Articles

Transcriptomic analysis reveals critical genes for the hair follicle of Inner Mongolia cashmere goat from catagen to telogen.

There are two main types of hair follicle in Inner Mongolia Cashmere goats, the primary hair follicle (PHF) producing hair fibers and the secondary hair follicle (SHF) producing cashmere fibers. Of both fibers from cashmere-bearing goats in Aerbasi, Inner Mongolia, the timing of cyclical phases for the cashmere have been well clarified but hair fibers have been less noticeable. Herein, we evaluated transcriptome of PHF and SHF from the same three goats in Aerbasi at the catagen- and telogen phase of cashmere growth. We totally found 1977 DEGs between PHFs at the telogen and catagen phases of SHF, 1199 DEGs between telogen- and catagen SHF, 2629 DEGs between PHF at the catagen phase of SHF and catagen SHF, and 755 DEGs between PHF at the telogen phase of SHF and telogen SHF. By analyzing gene functions based on GO and KEGG database, we found that the DEGs have functions in muscle contraction and muscle filament sliding between catagen- and telogen SHF, indicating that arrector pilli muscles might play a role on the transition from catagen to telogen. Moreover, considering that the enriched GO and KEGG categories of the DEGs between PHF and SHF, we suggested that part of PHF might rest in their own anagen phase when SHF are at catagen, but PHF might enter into the telogen phase at SHF’s telogen. Finally, we highly recommended the several potential genes acting as the regulators of the transition between growth phases including IL17RB and eight members of ZNF. These results provide insight into molecular mechanisms on the transition of SHF from catagen to telogen together with PHF’s growth situation at SHF’s catagen and telogen in Inner Mongolia Cashmere goats.

T Cell Leukemia/Lymphoma 1A is essential for mouse epidermal keratinocytes proliferation promoted by insulin-like growth factor 1.

T Cell Leukemia/Lymphoma 1A is expressed during B-cell differentiation and, when over-expressed, acts as an oncogene in mouse (Tcl1a) and human (TCL1A) B-cell chronic lymphocytic leukemia (B-CLL) and T-cell prolymphocytic leukemia (T-PLL). Furthermore, in the murine system Tcl1a is expressed in the ovary, testis and in pre-implantation embryos, where it plays an important role in blastomere proliferation and in embryonic stem cell (ESC) proliferation and self-renewal. We have also observed that Tcl1-/- adult mice exhibit alopecia and deep ulcerations. This finding has led us to investigate the role of TCL1 in mouse skin and hair follicles. We have found that TCL1 is expressed in the proliferative structure (i.e. the secondary hair germ) and in the stem cell niche (i.e. the bulge) of the hair follicle during regeneration phase and it is constitutively expressed in the basal layer of epidermis where it is required for the correct proliferative–differentiation program of the keratinocytes (KCs). Taking advantage of the murine models we have generated, including the Tcl1-/- and the K14-TCL1 transgenic mouse, we have analysed the function of TCL1 in mouse KCs and the molecular pathways involved. We provide evidence that in the epidermal compartment TCL1 has a role in the regulation of KC proliferation, differentiation, and apoptosis. In particular, the colony-forming efficiency (CFE) and the insulin-like growth factor 1 (IGF1)-induced proliferation are dramatically impaired, while apoptosis is increased, in KCs from Tcl1-/- mice when compared to WT. Moreover, the expression of differentiation markers such as cytokeratin 6 (KRT6), filaggrin (FLG) and involucrin (IVL) are profoundly altered in mutant mice (Tcl1-/-). Importantly, by over-expressing TCL1A in basal KCs of the K14-TCL1 transgenic mouse model, we observed a significant rescue of cell proliferation, differentiation and apoptosis of the mutant phenotype. Finally, we found TCL1 to act, at least in part, via increasing phospho-ERK1/2 and decreasing phospho-P38 MAPK. Hence, our data demonstrate that regulated levels of Tcl1a are necessary for the correct proliferation and differentiation of the interfollicular KCs.

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

It is widely accepted that the periodic cycle of hair follicles is controlled by the biological clock, but the molecular regulatory mechanisms of the hair follicle cycle have not been thoroughly studied. The secondary hair follicle of the cashmere goat is characterized by seasonal periodic changes throughout life. In the hair follicle cycle, the initiation of hair follicles is of great significance for hair follicle regeneration. To provide a reference for hair follicle research, our study compared differences in mRNA expression and microRNA expression during the growth and repose stages of cashmere goat skin samples. Through microRNA and mRNA association analysis, we found microRNAs and target genes that play major regulatory roles in hair follicle initiation. We further constructed an mRNA-microRNA interaction network and found that hair follicle initiation and development were related to MiR-195 and the genes CHP1, SMAD2, FZD6 and SIAH1.

Whole-genome bisulfite sequencing of goat skins identifies signatures associated with hair cycling

BackgroundHair follicles (HFs), upon development, undergo repetitive cycles of growth (anagen), regression (catagen), and rest (telogen). The transition between the stages is determined by multiple molecular signals, including DNA methylation, which plays important roles in mammalian cellular identity and is essential for the development of HFs. Secondary hair follicles (SHFs) in cashmere goat exhibit classic cyclic hair development, and little has been done on a genome-wide scale to examine potentially methylated genes involved in the hair cyclic transition.ResultsGenome-wide DNA methylation profiles between skin tissues sampled during the anagen and telogen stages in cashmere goats were investigated using whole-genome bisulfite sequencing (WGBS). The methylation status was observed to be higher in the skin samples with HFs in the telogen than those in the anagen stage. A total of 1311 differentially methylated regions (DMRs) were identified between the two groups, which contained 493 fully annotated DMR-related genes (DMGs) (269 Hyper- DMGs and 224 Hypo-DMGs). Furthermore, a significant over-representation of the functional categories for DMGs related to immune response and intercellular crosstalk during hair cycling was observed. By integrating DNA methylation and mRNA expression data, we revealed that four genes (FMN1, PCOLCE, SPTLC3, and COL5A1) are crucial factors for elucidating epigenetic mechanisms contributing to the telogen-to-anagen transition.ConclusionOur study provided systematic methylome maps pertaining to the hair cycling stages (anagen vs telogen) at a single-base resolution, and revealed stage-specific methylation loci during cashmere growth or quiescence. Furthermore, we identified epigenetically regulated genes that are potentially involved in HF development and growth in cashmere goats, and likely in other mammal species.

Effects of photoperiod on nutrient digestibility, hair follicle activity and cashmere quality in Inner Mongolia white cashmere goats.

ObjectiveThis study investigated the effects of photoperiod on nutrient digestibility, hair follicle (HF) activity and cashmere quality in Inner Mongolia white cashmere goats.MethodsTwenty-four female (non-pregnant) Inner Mongolia white cashmere goats aged 1 to 1.5 years old with similar live weights (mean, 20.36±2.63 kg) were randomly allocated into two groups: a natural daily photoperiod group (NDPP group:10 to 16 h light, n = 12) and a short daily photoperiod group (SDPP group: 7 h light:17 h dark, n = 12). All the goats were housed in individual pens and fed the same diets from May 15 to October 15, 2015. The digestibility of crude protein (CP), dry matter (DM), and neutral detergent fiber (NDF) were measured in different months, along with secondary hair follicle (SHF) activity, concentration of melatonin (MEL), and cashmere quality.ResultsAlthough there was no significant difference in the live weights of goats between the SDPP and NDPP groups (p>0.05), the CP digestibility of goats in the SDPP group was significantly increased compared to the NDPP group in July, September, and October (p<0.05). For the DM and NDF digestibility of goats, a significant increase (p<0.05) was found during in September in the SDPP group. Furthermore, compared to the NDPP group, the SHF activity in July, the MEL concentration in July, and the cashmere fiber length and fiber weight in October were significantly increased in the SDPP group (p<0.05).ConclusionThe cashmere production of Inner Mongolia white cashmere goats was increased without obvious deleterious effects on the cashmere fibers in the SDPP group (metabolizable energy, 8.34 MJ/kg; CP, 11.16%; short daily photoperiod, 7 h light:17 h dark).

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.

Genome-wide discovery of lincRNAs with spatiotemporal expression patterns in the skin of goat during the cashmere growth cycle

BackgroundLong intergenic noncoding RNAs (lincRNAs) have been recognized in recent years as key regulators of biological processes. However, lincRNAs in goat remain poorly characterized both across various tissues and during different developmental stages in goat (Capra hircus).ResultsWe performed the genome-wide discovery of the lincRNAs in goat by combining the RNA-seq dataset that were generated from 28 cashmere goat skin samples and the 12 datasets of goat tissues downloaded from the NCBI database. We identified a total of 5546 potential lincRNA transcripts that overlapped 3641 lincRNA genes. These lincRNAs exhibited a tissue-specific pattern. Specifically, there are 584 lincRNAs expressed exclusively in only one tissue, and 91 were highly expressed in hair follicle (HF). In addition, 2350 protein-coding genes and 492 lincRNAs were differentially expressed in the skin of goat. The majority exhibited the remarkable differential expression during the transition of the goat skin from the May–June to August–October time point, which covered the different seasons. Fundamental biological processes, such as skin development, were significantly enriched in these genes. Furthermore, we identified several lincRNAs highly expressed in the HF, which exhibited not only the co-expression pattern with the key factors to the HF development but also the activated expression in the August to October time point. Intriguingly, one of spatiotemporal lincRNAs, linc-chig1598 could be a potential regulator of distal-less homeobox 3 expression during the secondary hair follicle growth.ConclusionsThis study will facilitate future studies aimed at unravelling the function of lincRNAs in hair follicle development.

Melatonin promotes Cashmere goat (Capra hircus) secondary hair follicle growth: a view from integrated analysis of long non-coding and coding RNAs

ABSTRACT The role of melatonin in promoting the yield of Cashmere goat wool has been demonstrated for decades though there remains a lack of knowledge regarding melatonin mediated hair follicle growth. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are widely transcribed in the genome and play ubiquitous roles in regulating biological processes. However, the role of lncRNAs in regulating melatonin mediated hair follicle growth remains unclear. In this study, we established an in vitro Cashmere goat secondary hair follicle culture system, and demonstrated that 500 ng/L melatonin exposure promoted hair follicle fiber growth. Based on long intergenic RNA sequencing, we demonstrated that melatonin promoted hair follicle elongation via regulating genes involved in focal adhesion and extracellular matrix receptor pathways and further cis predicting of lncRNAs targeted genes indicated that melatonin mediated lncRNAs mainly targeted vascular smooth muscle contraction and signaling pathways regulating the pluripotency of stem cells. We proposed that melatonin exposure not only perturbed key signals secreted from hair follicle stem cells to regulate hair follicle development, but also mediated lncRNAs mainly targeted to pathways involved in the microvascular system and extracellular matrix, which constitute the highly orchestrated microenvironment for hair follicle stem cell. Taken together, our findings here provide a profound view of lncRNAs in regulating Cashmere goat hair follicle circadian rhythms and broaden our knowledge on melatonin mediated hair follicle morphological changes.

Integrative analysis reveals ncRNA-mediated molecular regulatory network driving secondary hair follicle regression in cashmere goats

BackgroundCashmere is a keratinized product derived from the secondary hair follicles (SHFs) of cashmere goat skins. The cashmere fiber stops growing following the transition from the actively proliferating anagen stage to the apoptosis-driven catagen stage. However, little is known regarding the molecular mechanisms responsible for the occurrence of apoptosis in SHFs, especially as pertains to the role of non-coding RNAs (ncRNAs) and their interactions with other molecules. Hair follicle (HF) degeneration is caused by localized apoptosis in the skin, while anti-apoptosis pathways may coexist in adjacent HFs. Thus, elucidating the molecular interactions responsible for apoptosis and anti-apoptosis in the skin will provide insights into HF regression.ResultsWe used multiple-omics approaches to systematically identify long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and mRNAs expressed in cashmere goat skins in two crucial phases (catagen vs. anagen) of HF growth. Skin samples were collected from three cashmere goats at the anagen (September) and catagen (February) stages, and six lncRNA libraries and six miRNA libraries were constructed for further analysis. We identified 1122 known and 403 novel lncRNAs in the goat skins, 173 of which were differentially expressed between the anagen and catagen stages. We further identified 3500 gene-encoding transcripts that were differentially expressed between these two phases. We also identified 411 known miRNAs and 307 novel miRNAs, including 72 differentially expressed miRNAs. We further investigated the target genes of lncRNAs via both cis- and trans-regulation during HF growth. Our data suggest that lncRNAs and miRNAs act synergistically in the HF growth transition, and the catagen inducer factors (TGFβ1 and BDNF) were regulated by miR-873 and lnc108635596 in the lncRNA-miRNA-mRNA networks.ConclusionThis study enriches the repertoire of ncRNAs in goats and other mammals, and contributes to a better understanding of the molecular mechanisms of ncRNAs involved in the regulation of HF growth and regression in goats and other hair-producing species.

Gene Expression and Localization of LAMTOR3 in the Skin Cells of Liaoning Cashmere Goats

ABSTRACTLiaoning cashmere goats are the most precious genetic resources in China. The function of LAMTOR3 [late endosomal/lysosomal adaptor, mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin activator 3/MAPK scaffold protein 1] gene is expressed in the skin of Liaoning cashmere goats. In situ hybridization (ISH) found that LAMTOR3 is expressed in the inner root sheath (IRS) of hair follicles. During the anagen or catagen phase, the expression of LAMTOR3 is higher in secondary hair follicles than in primary hair follicles. Expression of LAMTOR3 in skin cells treated with melatonin or insulin-like growth factor-1 (IGF-1) is lower than in untreated cells. In addition, the simultaneous treatment of fibroblast growth factor 5 and melatonin decrease the expression of LAMTOR3 in skin cells. The simultaneous treatment with melatonin and 10−5 g/L IGF-1 or 10−4 g/L IGF-1 increases the expression of LAMTOR3 gene in skin cells. If Noggin expression is decreased, then LAMTOR3 expression is increased. This hypothesis suggested that LAMTOR3 influences the character of cashmere fiber, and it may regulate the development of hair follicle and cashmere growth by inducing the MAPK signaling pathway.

Cashmere growth control in Liaoning cashmere goat by ovarian carcinoma immunoreactive antigen-like protein 2 and decorin genes.

ObjectiveThe study investigated the biological functions and mechanisms for controlling cashmere growth of Liaoning cashmere goat by ovarian carcinoma immunoreactive antigen-like protein 2 (OCIAD2) and decorin (DCN) genes.MethodscDNA library of Liaoning cashmere goat was constructed in early stages. OCIAD2 and DCN genes related to cashmere growth were identified by homology analysis comparison. The expression location of OCIAD2 and DCN genes in primary and secondary hair follicles (SF) was performed using in situ hybridization. The expression of OCIAD2 and DCN genes in primary and SF was performed using real-time polymerase chain reaction (PCR).ResultsIn situ hybridization revealed that OCIAD2 and DCN were expressed in the inner root sheath of Liaoning cashmere goat hair follicles. Real-time quantitative PCR showed that these genes were highly expressed in SF during anagen, while these genes were highly expressed in primary hair follicle in catagen phase. Melatonin (MT) inhibited the expression of OCIAD2 and promoted the expression of DCN. Insulin-like growth factors-1 (IGF-1) inhibited the expression of OCIAD2 and DCN, while fibroblast growth factors 5 (FGF5) promoted the expression of these genes. MT and IGF-1 promoted OCIAD2 synergistically, while MT and FGF5 inhibited the genes simultaneously. MT+IGF-1/MT+FGF5 inhibited DCN gene. RNAi technology showed that OCIAD2 expression was promoted, while that of DCN was inhibited.ConclusionActivation of bone morphogenetic protein (BMP) signaling pathway up-regulated OCIAD2 expression and stimulated SF to control cell proliferation. DCN gene affected hair follicle morphogenesis and periodic changes by promoting transforming growth factor-β (TGF-β) and BMP signaling pathways. OCIAD2 and DCN genes have opposite effects on TGF-β signaling pathway and inhibit each other to affect the hair growth.

A Case Report of Symptomatic Rathke's Cleft Cyst

Background: Rathke's cleft cyst (RCC) is a not-so-common pituitary developmental disorder, it is a benign growth found on the pituitary gland in the brain, specifically a fluid-filled cyst in the posterior portion of the anterior pituitary gland. Symptomatic cysts are very rare. With only few cases have been documented in the literature. Aim of the work: this study aimed to assess the effect of corticosteroids on patientswithsymptomatic Rathke’s cleft cyst. Methodology: we reported a rare case of a 21 years old male patient, who was referred from a primary health center to the endocrine clinic with the complain of decreased visual acuity, blurred vision, and headache. On examination, there were no signs of puberty, no secondary sexual hair, truncal and generalized obesity. The fundus examination showed bilateral temporal pallor, with pale disc and papilledema. On the basis of symptoms and examination of the patient we suspected a lesion in the brain obstructing the optic pathway and therefore suggested MRI. Conclusion: this case led us to conclude that Rathke's cleft cysts should be considered in the differential diagnosis of patients who present with adrenal insufficiency and that the cysts can be reduced by glucocorticoids.

Identification of the Caprine Keratin-Associated Protein 20-2 (KAP20-2) Gene and Its Effect on Cashmere Traits.

The gene encoding the high glycine/tyrosine keratin-associated protein 20-2 (KAP20-2) gene has been described in humans, but has not been identified in any livestock species. A search for similar sequences in the caprine genome using the human KAP20-2 gene (KRTAP20-2) revealed a homologous sequence on chromosome 1. Three different banding patterns representing distinct sequences (A–C) in Longdong cashmere goats were identified using polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) analysis. These sequences shared high sequence similarity with the human and mouse KRTAP20-2 sequences, suggesting that A–C are caprine variants of the human and mouse genes. Four single nucleotide polymorphisms (SNPs) were identified, and three of them were non-synonymous. KRTAP20-2 was found to be expressed in secondary hair follicles, but not in heart, liver, lung, kidney, spleen, or longissimus dorsi muscle. The presence of A was associated with increased cashmere fibre weight, while the presence of B was associated with a decrease in cashmere fibre weight and curly fibre length. Goats with genotype AA had a higher cashmere fibre weight and a higher curly fibre length than those with genotypes AB or BB. These results indicate that caprine KRTAP20-2 variation may have value as a genetic marker for improving cashmere fibre weight.

Hairy black-hole solutions in generalized Proca theories

We present a family of exact black-hole solutions on a static spherically symmetric background in second-order generalized Proca theories with derivative vector-field interactions coupled to gravity. We also derive non-exact solutions in power-law coupling models including vector Galileons and numerically show the existence of regular black holes with a primary hair associated with the longitudinal propagation. The intrinsic vector-field derivative interactions generally give rise to a secondary hair induced by non-trivial field profiles. The deviation from General Relativity is most significant around the horizon and hence there is a golden opportunity for probing the Proca hair by the measurements of gravitational waves (GWs) in the regime of strong gravity.

Characterization of a new, inducible transgenic mouse model with GFP expression in melanocytes and their precursors

Melanocytes are neural crest-derived cells that are responsible for mammalian hair follicle (HF) pigmentation. The Dct-LacZ transgenic mouse is extensively used to study melanocyte biology but lacks conditionally-inducible labelling and fluorescent labelling, enabling specific, viable isolation of melanocytes using fluorescence-activated cell sorting (FACS). Here, we have generated a Tet-off bitransgenic mouse model, Dct-H2BGFP, containing Dct-tTA and TRE-H2BGFP transgenes. Characterization of Dct-H2BGFP mice confirmed a pattern of Dct-H2BGFP expression in melanoblasts, melanocyte stem cells (McSCs), and terminally differentiated melanocytes similar to the expression pattern of previously published mouse models Dct-LacZ and iDct-GFP. GFP expression is regulated by doxycycline. GFP is shown to co-localize with melanocyte label-retaining cells (LRCs) identified through BrdU retention. The GFP-expressing cells identified in vivo in the bulge and the secondary hair germ of telogen HFs of Dct-H2BGFP mice express the melanocyte and melanocyte stem cell markers Dct and Kit. Using Dct-H2BGFP mice, we separated GFP-expressing cells from the telogen HF based on FACS and showed that GFP-expressing cells express high levels of Kit and Dct, and lower levels of HF epithelial keratin genes. We also show that GFP-expressing cells express high levels of the melanocyte differentiation genes Tyr, Tyrp1, and Pmel17, further substantiating their identity within the melanocyte lineage. Thus, Dct-H2BGFP mice are not only useful for the in vivo identification of melanocytic cells, but also for isolating them viably and studying their molecular and biological properties.

A lncRNA-H19 transcript from secondary hair follicle of Liaoning cashmere goat: Identification, regulatory network and expression regulated potentially by its promoter methylation

The H19 transcript (imprinted maternally expressed transcript) is well-known as long noncoding RNA (lncRNA), and it is thought to be associated with the inductive capacity of dermal papilla cells for hair-follicle reconstruction. In this study, we isolated and characterized a lncRNA-H19 transcript from the secondary hair follicle of Liaoning cashmere goat. Also, we investigated its transcriptional pattern and methylation status of H19 gene in secondary hair follicle of this breed during different stages of hair follicle cycle. Nucleotide composition analysis indicated that guanine (G) and cytosine (C) are the dominant nucleotides in the lncRNA-H19 transcript of Liaoning cashmere goat with the highest frequency distribution (11.25%) of GG nucleotide pair. The regulatory network showed that lncRNA-H19 transcript appears to have remarkably diverse regulatory relationships with its related miRNAs and the potential target genes. In secondary hair follicle, the relative expression of lncRNA-H19 transcript at the anagen phase is significantly higher than that at both telogen and catagen phases suggesting that lncRNA-H19 transcript might play essential roles in the formation and growth of cashmere fiber of goat. Methylation analysis indicated that the methylation of the promoter region of H19 gene most likely participates in its transcriptional suppression in secondary hair follicle of Liaoning cashmere goat.

NF-κB Participates in Mouse Hair Cycle Control and Plays Distinct Roles in the Various Pelage Hair Follicle Types

The transcription factor NF-κB controls key features of hair follicle (HF) development, but the role of NF-κB in adult HF cycle regulation remains obscure. Using NF-κB reporter mouse models, strong NF-κB activity was detected in the secondary hair germ of late telogen and early anagen HFs, suggesting a potential role for NF-κB in HF stem/progenitor cell activation during anagen induction. At mid-anagen, NF-κB activity was observed in the inner root sheath and unilaterally clustered in the HF matrix, which indicates that NF-κB activity is also involved in hair fiber morphogenesis during HF cycling. A mouse model with inducible NF-κB suppression in the epithelium revealed pelage hair-type-dependent functions of NF-κB in cycling HFs. NF-κB participates in telogen-anagen transition in awl and zigzag HFs, and is required for zigzag hair bending and guard HF cycling. Interestingly, zigzag hair shaft bending depends on noncanonical NF-κB signaling, which previously has only been associated with lymphoid cell biology. Furthermore, loss of guard HF cycling suggests that in this particular hair type, NF-κB is indispensable for stem cell activation, maintenance, and/or growth.

KIL FOLİKÜLÜ GELİŞİMİ ÜZERİNE ETKİLİ GENLER

Molecular studies have come to the fore within the scope of the development of animal breeding. For this reason, genetic studies made or will be made on production and quality of hair in animals have become more of an issue. In animals like goat and sheep been rich in terms of textile products, hair structure is constitutively divided into two as primary and secondary. In studies made in these follicles, it is identified that the 10077 genes are expressed in the primary hair follicles and the 7772 genes are expressed in the secondary hair follicles. In this review, it will be summarized the anatomy and the process of development of the hair follicle generating the animal fibers, genes had an effect upon development of hair and the processes formed the hair follicle of these genes. In addition, it will be mentioned about structure of hair follicle and efficiency of genes; morphogenesis and cycle stages; anagen, catagen and telogen. The scope of this work includes examination of genes associated with quality from the formation of hair follicle to starting of first cycle and in the repetition of process continually.

Wnt/β-catenin signaling promotes aging-associated hair graying in mice.

Canities is an obvious sign of aging in mouse and human, shown as hair graying. Melanocytes in the hair follicle show cyclic activity with hair cycling, which transitions from anagen, catagen to telogen. How the hairs turn gray during aging is not completely uncovered. Here, by using immunostaining and LacZ staining in Dct-LacZ mice, we show that β-catenin is expressed in melanocytes during hair cycling. RT-PCR, western blot and immunostaining show that β-catenin expression is significantly increased in both anagen and telogen skin of aged mice, when compared to the anagen and telogen skin of young mice, respectively. Overexpression of Wnt10b not only accelerates hair follicle to enter anagen phase, but also promotes melanocytes differentiation in young adult mice (2-month old), with increased β-catenin expression in melanocytes at the secondary hair germ and matrix region of regenerated hair follicles. Overexpression of Wnt10b also promotes melanocyte progenitor cells differentiation in vitro. Our data suggest that increased Wnt signaling promotes excessive differentiation of melanocytes, leading to exhaustion of melanocyte stem cells and eventually canities in aged mice.

LncRNAs in Secondary Hair Follicle of Cashmere Goat: Identification, Expression, and Their Regulatory Network in Wnt Signaling Pathway

ABSTRACTLong noncoding RNAs (lncRNAs) are a novel class of eukaryotic transcripts. They are thought to act as a critical regulator of protein-coding gene expression. Herein, we identified and characterized 13 putative lncRNAs from the expressed sequence tags from secondary hair follicle of Cashmere goat. Furthermore, we investigated their transcriptional pattern in secondary hair follicle of Liaoning Cashmere goat during telogen and anagen phases. Also, we generated intracellular regulatory networks of upregulated lncRNAs at anagen in Wnt signaling pathway based on bioinformatics analysis. The relative expression of six putative lncRNAs (lncRNA-599618, -599556, -599554, -599547, -599531, and -599509) at the anagen phase is significantly higher than that at telogen. Compared with anagen, the relative expression of four putative lncRNAs (lncRNA-599528, -599518, -599511, and -599497) was found to be significantly upregulated at telogen phase. The network generated showed that a rich and complex regulatory relationship of the putative lncRNAs and related miRNAs with their target genes in Wnt signaling pathway. Our results from the present study provided a foundation for further elucidating the functional and regulatory mechanisms of these putative lncRNAs in the development of secondary hair follicle and cashmere fiber growth of Cashmere goat.