Effects of transforming growth factor beta 1 in the hair cycle

Novel Effect of Hyaluronan and Proteoglycan Link Protein 1 (HAPLN1) on Hair Follicle Cells Proliferation and Hair Growth

Hair loss is a common condition that can have a negative impact on an individual's quality of life. The severe side effects and the low efficacy of current hair loss medications create unmet needs in the field of hair loss treatment. Hyaluronan and Proteoglycan Link Protein 1 (HAPLN1), one of the components of the extracellular matrix, has been shown to play a role in maintaining its integrity. HAPLN1 was examined for its ability to impact hair growth with less side effects than existing hair loss treatments. HAPLN1 was predominantly expressed in the anagen phase in three stages of the hair growth cycle in mice and promotes the proliferation of human hair matrix cells. Also, recombinant human HAPLN1 (rhHAPLN1) was shown to selectively increase the levels of transforming growth factor-β receptor II in human hair matrix cells. Furthermore, we observed concomitant activation of the ERK1/2 signaling pathway following treatment with rhHAPLN1. Our results indicate that rhHAPLN1 elicits its cell proliferation effect via the TGF-β2-induced ERK1/2 pathway. The prompt entering of the hair follicles into the anagen phase was observed in the rhHAPLN1-treated group, compared to the vehicle-treated group. Insights into the mechanism underlying such hair growth effects of HAPLN1 will provide a novel potential strategy for treating hair loss with much lower side effects than the current treatments.

Effects of taxifolin from enzymatic hydrolysis of Rhododendron mucrotulatum on hair growth promotion

Flavonoid aglycones possess biological activities, such as antioxidant and antidiabetic activities compared to glycosides. Taxifolin, a flavonoid aglycones, is detected only in trace amounts in nature and is not easily observed. Therefore, in this study, to investigate the hair tonic and hair loss inhibitors effect of taxifolin, high content of taxifolin aglycone extract was prepared by enzymatic hydrolysis. Taxifolin effectively regulates the apoptosis of dermal papilla cells, which is associated with hair loss, based on its strong antioxidant activities. However, inhibition of dihydrotestosterone (DHT), which is a major cause of male pattern hair loss, was significantly reduced with taxifolin treatment compared with minoxidil, as a positive control. It was also confirmed that a representative factor for promoting hair growth, IGF-1, was significantly increased, and that TGF-β1, a representative biomarker for hair loss, was significantly reduced with taxifolin treatment. These results suggest that taxifolin from enzymatic hydrolysis of RM is a potential treatment for hair loss and a hair growth enhancer.

A hypothetical pathogenesis model for androgenic alopecia: clarifying the dihydrotestosterone paradox and rate-limiting recovery factors

Androgenic alopecia, also known as pattern hair loss, is a chronic progressive condition that affects 80% of men and 50% of women throughout a lifetime. But despite its prevalence and extensive study, a coherent pathology model describing androgenic alopecia's precursors, biological step-processes, and physiological responses does not yet exist. While consensus is that androgenic alopecia is genetic and androgen-mediated by dihydrotestosterone, questions remain regarding dihydrotestosterone's exact role in androgenic alopecia onset. What causes dihydrotestosterone to increase in androgenic alopecia-prone tissues? By which mechanisms does dihydrotestosterone miniaturize androgenic alopecia-prone hair follicles? Why is dihydrotestosterone also associated with hair growth in secondary body and facial hair? Why does castration (which decreases androgen production by 95%) stop pattern hair loss, but not fully reverse it? Is there a relationship between dihydrotestosterone and tissue remodeling observed alongside androgenic alopecia onset? We review evidence supporting and challenging dihydrotestosterone's causal relationship with androgenic alopecia, then propose an evidence-based pathogenesis model that attempts to answer the above questions, account for additionally-suspected androgenic alopecia mediators, identify rate-limiting recovery factors, and elucidate better treatment targets. The hypothesis argues that: (1) chronic scalp tension transmitted from the galea aponeurotica induces an inflammatory response in androgenic alopecia-prone tissues; (2) dihydrotestosterone increases in androgenic alopecia-prone tissues as part of this inflammatory response; and (3) dihydrotestosterone does not directly miniaturize hair follicles. Rather, dihydrotestosterone is a co-mediator of tissue dermal sheath thickening, perifollicular fibrosis, and calcification - three chronic, progressive conditions concomitant with androgenic alopecia progression. These conditions remodel androgenic alopecia-prone tissues - restricting follicle growth space, oxygen, and nutrient supply - leading to the slow, persistent hair follicle miniaturization characterized in androgenic alopecia. If true, this hypothetical model explains the mechanisms by which dihydrotestosterone miniaturizes androgenic alopecia-prone hair follicles, describes a rationale for androgenic alopecia progression and patterning, makes sense of dihydrotestosterone's paradoxical role in hair loss and hair growth, and identifies targets to further improve androgenic alopecia recovery rates: fibrosis, calcification, and chronic scalp tension.

Extraction and Detection of mRNA from Horsehair

After RNA extraction from horsehair shafts and roots, the mRNAs of beta-actin, muscle-type phosphofructokinase, and transforming growth factor-beta1 were detected by reverse transcription polymerase chain reaction assay. Low amounts of RNA were present in the horsehair. These specific mRNA transcripts were readily detected when more than three hair roots were used. However, detection of the mRNA transcripts was difficult in the hair shaft. These findings indicate that the small amounts of residual RNA in horsehair roots can be utilized as samples for molecular biological analysis.

MEL4B3, a novel mRNA is induced in skin tumors and regulated by TGF-beta and pro-inflammatory cytokines

Tumor-stroma interactions play a decisive role in the growth and metastasis of solid tumors, and involve signalling either by soluble mediators or direct cell-cell interaction. Here, we report the isolation and characterisation of a novel cDNA (MEL4B3), which is induced in cultured dermal fibroblasts exposed to supernatants of melanoma cell lines. MEL4B3 shares high homology with two predicted cDNA sequences for which no activity has so far been described. In situ hybridisation revealed the expression of MEL4B3 in malignant melanoma increasing with tumor depth; in basal cell carcinoma and in squamous cell carcinoma. MEL4B3 was barely detectable in normal skin or non-malignant melanocytic naevi. Furthermore, MEL4B3 was expressed at high level in the epidermis of psoriatic skin. In vitro, the expression of MEL4B3 was found to be induced by the exposure of human dermal fibroblasts to melanoma cell culture supernatants or to transforming growth factor-beta, interleukin-1 and tumor necrosis factor-alpha. The expression MEL4B3 therefore reflects closely cell activation occurring during tumor growth, metastasis and inflammation.

The chemotactic effect of a dermal papilla cell-derived factor on outer root sheath cells

The effect of cultured normal human dermal papilla cells (DPCs) and conditioned medium prepared with cultured DPCs on chemotactic migration of human hair outer root sheath cells (ORSCs) was examined quantitatively. ORSCs showed significantly increased migration toward both cultured DPCs and the conditioned medium suggesting that DPCs produce and secrete a paracrine factor(s), which attracts hair follicle epithelial cells. Some soluble factors, which are reportedly produced by DPCs, such as insulin-like growth factor-I (IGF-I), hepatocyte growth factor (HGF), vascular endothelial cell growth factor (VEGF), and transforming growth factor-beta1 (TGF-beta1), were also examined. ORSCs showed dramatically increased migration toward IGF-I and HGF at concentrations of 1-10 ng/ml. On the other hand, neither VEGF nor TGF-beta1 showed any effect on the chemotaxis of ORSCs. It is interesting that all factors involving mitogenic activity did not always have chemotactic activity for ORSCs. This is the first report to establish that IGF-I and HGF have not only a growth stimulatory but also a chemotactic effect on ORSCs. In addition, the method presented here may help to simplify chemotaxis assays of any type of epithelial keratinocytes with poor mobility.

Controls of hair follicle cycling

Nearly 50 years ago, Chase published a review of hair cycling in which he detailed hair growth in the mouse and integrated hair biology with the biology of his day. In this review we have used Chase as our model and tried to put the adult hair follicle growth cycle in perspective. We have tried to sketch the adult hair follicle cycle, as we know it today and what needs to be known. Above all, we hope that this work will serve as an introduction to basic biologists who are looking for a defined biological system that illustrates many of the challenges of modern biology: cell differentiation, epithelial-mesenchymal interactions, stem cell biology, pattern formation, apoptosis, cell and organ growth cycles, and pigmentation. The most important theme in studying the cycling hair follicle is that the follicle is a regenerating system. By traversing the phases of the cycle (growth, regression, resting, shedding, then growth again), the follicle demonstrates the unusual ability to completely regenerate itself. The basis for this regeneration rests in the unique follicular epithelial and mesenchymal components and their interactions. Recently, some of the molecular signals making up these interactions have been defined. They involve gene families also found in other regenerating systems such as fibroblast growth factor, transforming growth factor-beta, Wnt pathway, Sonic hedgehog, neurotrophins, and homeobox. For the immediate future, our challenge is to define the molecular basis for hair follicle growth control, to regenerate a mature hair follicle in vitro from defined populations, and to offer real solutions to our patients' problems.

New roles for glial cell line-derived neurotrophic factor and neurturin: involvement in hair cycle control

Glial cell line-derived neurotrophic factor (GDNF), neurturin (NTN), and their receptors, GDNF family receptor alpha-1 (GFRalpha-1) and GDNF family receptor alpha-2 (GFRalpha-2), are critically important for kidney and nervous system development. However, their role in skin biology, specifically in hair growth control, is as yet unknown. We have studied expression and function of GDNF, neurturin, GFRalpha-1, and GFRalpha-2 in murine skin during the cyclic transformation of the hair follicle (HF) from its resting state (telogen) to active growth (anagen) and then through regression (catagen) back to telogen. GDNF protein and GFRalpha-1 messenger RNA are prominently expressed in telogen skin, which lacks NTN and GFRalpha-2 transcripts. Early anagen development is accompanied by a significant decline in the skin content of GDNF protein and GFRalpha-1 transcripts. During the anagen-catagen transition, GDNF, GFRalpha-1, NTN, and GFRalpha-2 transcripts reach maximal levels. Compared with wild-type controls, GFRalpha-1 (+/-) and GFRalpha-2 (-/-) knockout mice show a significantly accelerated catagen development. Furthermore, GDNF or NTN administration significantly retards HF regression in organ-cultured mouse skin. This suggests important, previously unrecognized roles for GDNF/GFRalpha-1 and NTN/GFRalpha-2 signaling in skin biology, specifically in the control of apoptosis-driven HF involution, and raises the possibility that GFRalpha-1/GFRalpha-2 agonists/antagonists might become exploitable for the treatment of hair growth disorders that are related to abnormalities in catagen development.