Prostaglandin metabolism in human hair follicle

Hair Growth Promoting Effects of 15-Hydroxyprostaglandin Dehydrogenase Inhibitor in Human Follicle Dermal Papilla Cells

Prostaglandin E2 (PGE2) is known to be effective in regenerating tissues, and bimatoprost, an analog of PGF2α, has been approved by the FDA as an eyelash growth promoter and has been proven effective in human hair follicles. Thus, to enhance PGE2 levels while improving hair loss, we found dihydroisoquinolinone piperidinylcarboxy pyrazolopyridine (DPP), an inhibitor of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), using DeepZema®, an AI-based drug development program. Here, we investigated whether DPP improved hair loss in human follicle dermal papilla cells (HFDPCs) damaged by dihydrotestosterone (DHT), which causes hair loss. We found that DPP enhanced wound healing and the expression level of alkaline phosphatase in DHT-damaged HFDPCs. We observed that DPP significantly down-regulated the generation of reactive oxygen species caused by DHT. DPP recovered the mitochondrial membrane potential in DHT-damaged HFDPCs. We demonstrated that DPP significantly increased the phosphorylation levels of the AKT/ERK and activated Wnt signaling pathways in DHT-damaged HFDPCs. We also revealed that DPP significantly enhanced the size of the three-dimensional spheroid in DHT-damaged HFDPCs and increased hair growth in ex vivo human hair follicle organ culture. These data suggest that DPP exhibits beneficial effects on DHT-damaged HFDPCs and can be utilized as a promising agent for improving hair loss.

Comprehensive transcriptome profiling between balding and non-balding scalp of female pattern hair loss in Asian

While many gene expression studies have focused on male pattern baldness (MPB), few studies have investigated the genetic differences between bald and non-bald hair follicles in female pattern hair loss (FPHL). This study aimed to identify molecular biomarkers associated with FPHL through genetic analysis of paired bald and non-bald hair follicles from 18 FPHL patients, using next-generation sequencing (NGS) techniques. RNA transcriptome analysis was performed to identify differentially expressed genes (DEGs) between bald and non-bald hair follicles in FPHL. The DEGs were validated using real-time PCR, and protein expression was confirmed through immunohistochemistry and western blot analysis. Our findings suggest that HOXB13, SFRP2, PTGDS, CXCR3, SFRP4, SOD3, and DCN are significantly upregulated in bald hair follicles compared to non-bald hair follicles in FPHL. SFRP2 and PTGDS were found to be consistently highly expressed in bald hair follicles in all 18 samples. Additionally, elevated protein levels of SFRP2 and PTGDS were confirmed through western blot and immunohistochemical analysis. Our study identified SFRP2 and PTGDS as potential biomarkers for FPHL and suggests that they may play a role in inducing hair loss in this condition. These findings provide a foundation for further research on the pathogenesis of FPHL and potential therapeutic targets.

Multi-omics analysis of functional substances and expression verification in cashmere fineness

BACKGROUND

Numerous factors influence the growth and development of cashmere. Existing research on cashmere has predominantly emphasized a single omics level. Integrating multi-omics analyses can offer a more comprehensive understanding by encompassing the entire spectrum. This study more accurately and comprehensively identified the key factors influencing cashmere fineness using multi-omics analysis.

METHODS

This study used skin tissues of coarse cashmere type (CT_LCG) and fine cashmere type Liaoning cashmere goats (FT_LCG) for the analysis. This study employed an integrated approach involving transcriptomics, translatomics, proteomics, and metabolomics to identify substances associated with cashmere fineness. The findings were validated using parallel reaction monitoring (PRM) and multiple reaction monitoring (MRM) techniques.

RESULTS

The GO functional enrichment analysis identified three common terms: multicellular organismal process, immune system process, and extracellular region. Furthermore, the KEGG enrichment analysis uncovered the involvement of the arachidonic acid metabolic pathway. Protein expression trends were verified using PRM technology. The expression trends of KRT79, as confirmed by PRM, were consistent with those observed in TMT proteomics and exhibited a positive regulatory effect on cashmere fineness. Metabolite expression trends were confirmed using MRM technology. The expression trends of 9 out of 15 validated metabolites were in agreement with those identified in the non-targeted metabolomics analysis.

CONCLUSIONS

This study employed multi-omics analysis to identify key regulators of cashmere fineness, including PLA2G12A, KRT79, and prostaglandin B2. The findings of this study offer valuable data and establish a theoretical foundation for conducting comprehensive investigations into the molecular regulatory mechanisms and functional aspects of cashmere fineness.

Transcriptomic Analysis Reveals Candidate Ligand-Receptor Pairs and Signaling Networks Mediating Intercellular Communication between Hair Matrix Cells and Dermal Papilla Cells from Cashmere Goats

Hair fiber growth is determined by the spatiotemporally controlled proliferation, differentiation, and apoptosis of hair matrix cells (HMCs) inside the hair follicle (HF); however, dermal papilla cells (DPCs), the cell population surrounded by HMCs, manipulate the above processes via intercellular crosstalk with HMCs. Therefore, exploring how the mutual commutations between the cells are molecularly achieved is vital to understanding the mechanisms underlying hair growth. Here, based on our previous successes in cultivating HMCs and DPCs from cashmere goats, we combined a series of techniques, including in vitro cell coculture, transcriptome sequencing, and bioinformatic analysis, to uncover ligand-receptor pairs and signaling networks mediating intercellular crosstalk. Firstly, we found that direct cellular interaction significantly alters cell cycle distribution patterns and changes the gene expression profiles of both cells at the global level. Next, we constructed the networks of ligand-receptor pairs mediating intercellular autocrine or paracrine crosstalk between the cells. A few pairs, such as LEP-LEPR, IL6-EGFR, RSPO1-LRP6, and ADM-CALCRL, are found to have known or potential roles in hair growth by acting as bridges linking cells. Further, we inferred the signaling axis connecting the cells from transcriptomic data with the advantage of CCCExplorer. Certain pathways, including INHBA-ACVR2A/ACVR2B-ACVR1/ACVR1B-SMAD3, were predicted as the axis mediating the promotive effect of INHBA on hair growth via paracrine crosstalk between DPCs and HMCs. Finally, we verified that LEP-LEPR and IL1A-IL1R1 are pivotal ligand-receptor pairs involved in autocrine and paracrine communication of DPCs and HMCs to DPCs, respectively. Our study provides a comprehensive landscape of intercellular crosstalk between key cell types inside HF at the molecular level, which is helpful for an in-depth understanding of the mechanisms related to hair growth.

The efficacy of topical prostaglandin analogs for hair loss: A systematic review and meta-analysis

Background

Prostaglandin analogs have been found to have more versatile uses: treatment of open-angle glaucoma, high intraocular pressure, vitiligo, and other treatments. And prostaglandin analogs have been found to have an important role in the hair growth cycle. However, prostaglandin analogs have not been sufficiently studied for hair (including hair, eyelashes, and eyebrows) regeneration. In this study, a systematic review and meta-analysis of topical prostaglandin analogs on hair loss was performed.

Objective

The purpose of this meta-analysis is to determine the efficacy and safety of topical prostaglandin analogs for treating hair loss.

Methods

We searched PubMed, Embase, and Cochrane Library databases comprehensively. Data were pooled using Review Manager 5.4.1, and subgroup analyses were performed if necessary.

Results

There were six randomized controlled trials included in this meta-analysis. All studies compared prostaglandin analogs with placebo, and one trial consisted of two sets of data. The results showed that prostaglandin analogs could significantly improve the hair length and density (p < 0.001). As far as adverse events are concerned, there was no significant difference between the experimental group and the control group.

Conclusion

In patients with hair loss, the topical prostaglandin analogs have better therapeutic efficacy and safety than placebo. However, the best dose and frequency of experimental treatment require further studies.

Enhancement of hair growth through stimulation of hair follicle stem cells by prostaglandin E2 collagen matrix

Prostaglandin metabolism is involved in the regulation of the periodic process of hair follicles. Preliminary research data reported that prostaglandin E2 (PGE2) exhibits potential in hair growth. However, the relevant evidence is still insufficient. Herein, we prepared a PGE2 matrix by conjugating PGE2 with collagen via crosslinkers to avoid rapid degradation of PGE2 molecules in vivo. First, we measured the physical properties of the PGE2 matrix. A mouse model of hair loss was established, and PGE2 matrix subcutaneous injection was applied to evaluate hair growth. Under different treatments with the PGE2 matrix, the morphology of hair follicles, the dynamic expression of hair follicle stem cell markers and key regulators in the hair growth cycle were explored. Our data revealed that the PGE2 matrix increased the proportion of developing hair follicles at the early growth stage. Improvements in hair follicle stem cells, such as Sox9+ and Lgr5+ cells, have also been confirmed as therapeutic effects of PGE2 to stimulate hair follicle growth. Our study indicated that PGE2 exhibits effective roles in hair development during anagen. Furthermore, the results also highlight the potential of the PGE2 delivery system as a novel therapeutic strategy for the treatment of hair disorders in the future.

The physiological and pharmacological roles of prostaglandins in hair growth

Hair loss is a common status found among people of all ages. Since the role of hair is much more related to culture and individual identity, hair loss can have a great influence on well-being and quality of life. It is a disorder that is observed in only scalp patients with androgenetic alopecia (AGA) or alopecia areata caused by stress or immune response abnormalities. Food and Drug Administration (FDA)-approved therapeutic medicines such as finasteride, and minoxidil improve hair loss temporarily, but when they stop, they have a limitation in that hair loss occurs again. As an alternative strategy for improving hair growth, many studies reported that there is a relationship between the expression levels of prostaglandins (PGs) and hair growth. Four major PGs such as prostaglandin D2 (PGD₂), prostaglandin I2 (PGI₂), prostaglandin E2 (PGE₂), and prostaglandin F2 alpha (PGF₂α) are spatiotemporally expressed in hair follicles and are implicated in hair loss. This review investigated the physiological roles and pharmacological interventions of the PGs in the pathogenesis of hair loss and provided these novel insights for clinical therapeutics for patients suffering from alopecia.

Overview of human 20 alpha-hydroxysteroid dehydrogenase (AKR1C1): Functions, regulation, and structural insights of inhibitors

Human aldo-keto reductase family 1C1 (AKR1C1) is an important enzyme involved in human hormone metabolism, which is mainly responsible for the metabolism of progesterone in the human body. AKR1C1 is highly expressed and has an important relationship with the occurrence and development of various diseases, especially some cancers related to hormone metabolism. Nowadays, many inhibitors against AKR1C1 have been discovered, including some synthetic compounds and natural products, which have certain inhibitory activity against AKR1C1 at the target level. Here we briefly reviewed the physiological and pathological functions of AKR1C1 and the relationship with the disease, and then summarized the development of AKR1C1 inhibitors, elucidated the interaction between inhibitors and AKR1C1 through molecular docking results and existing co-crystal structures. Finally, we discussed the design ideals of selective AKR1C1 inhibitors from the perspective of AKR1C1 structure, discussed the prospects of AKR1C1 in the treatment of human diseases in terms of biomarkers, pre-receptor regulation and single nucleotide polymorphisms, aiming to provide new ideas for drug research targeting AKR1C1.

Clinical Patterns of Hair Loss in Men: Is Dihydrotestosterone the Only Culprit?

A number of pathways and factors including oxidative stress, inflammation, prostaglandins, vasculogenesis, Wnt/β-catenin, and transforming growth factor-β have been shown to be important in male androgenetic alopecia. There is limited but increasing evidence of the potential usefulness of antioxidants, anti-inflammatory agents, prostaglandins, and growth factors for treating of androgenetic alopecia. Lifestyle factors and comorbidities including cardiovascular risk factors have been shown to be associated with male androgenetic alopecia. Further study of these pathways, factors, and comorbidities is needed to better understand the pathophysiology, find potentially useful therapeutic targets, and ensure a comprehensive approach to the management of androgenetic alopecia in men.

The role of prostaglandins in androgenetic alopecia

BACKGROUND

Though androgenetic alopecia (AGA) is one of the most common diseases affecting both sexes and all races, its pathogenesis is not completely clarified. The aim of this study was to investigate the role of the four major prostaglandins (PGs) (PGE₂ , PGD₂ , PGF_2α , and PI₂ or prostacyclin) in the pathogenesis of AGA in males and females.

METHODS

Human scalp biopsies were obtained from 30 adults (17 males and 13 females) suffering from AGA and from 30 healthy adults (18 males and 12 females). In each subject, two skin biopsies were performed, one from the frontal bald area and another one from the occipital area with normal hair growth. In the healthy group, biopsies were taken from both areas too. In each sample, all four PGs were measured.

RESULTS

In the patient group, PGD₂ and prostacyclin or PGI₂ levels were increased in bald compared to haired scalp. On the contrary, measurements of PGE₂ and PGF_2α showed that they were diminished in bald areas compared to haired areas. PG levels in healthy samples were comparable to the haired areas.

CONCLUSION

These results support that there is a fine balance between these four proteins in scalp hair follicles, and its maintenance may be crucial for hair growth. Furthermore, their receptors could be potential targets for treatment of AGA.

Analysis of Bimatoprost-Induced changes on Rabbits eyelash Follicle: Clinical and Electron microscopic study

Objective

To analyze ultrastructural changes of rabbits' eyelash follicles treated with bimatoprost eye drops to increase our knowledge of how this drug works.

Methods

The study included 15 clinically healthy male rabbits. All rabbits were treated with bimatoprost 0.03% daily for 4 weeks with one drop of the topical eye drops applied to the conjunctival fornix of the right eyes; left eyes were used as controls. Eyelash lengths were measured before and after treatment. The eyelid of each animal was dissected for light and electron microscopic analysis.

Results

Both control and treated rabbit eyes matched regarding eyelash length before treatment (9.80±0.388mm vs 9.88±0.24mm) (P=0.108). There was a significant increase in eyelash length between control (9.75±0.33 mm) and treated rabbit eyes (11.60±0.46 mm) (P=0.369). Light and electron microscopy revealed, bimatoprost treated eyes had thick epidermis. The dermis contained two hairs growing out of the same hair follicle. Heavily keratinized Henle's layer, the cortical cells (Cx) have prominent nucleolus and cytoplasm is studded with melanin granules.

Conclusion

Bimatoprost-induced eyelash changes were not restricted to increased eyelash length, thickness, and pigmentation but also showed increased number of eyelashes within the same hair follicle which were stronger and could resist pulling from the skin without any evidence of inflammatory cells within the specimens. These changes occurred as early as 1 month of treatment, giving rise to thoughts about the possibility of using bimatoprost eye drops as a prophylaxis against madarosis associated with chemotherapy if it is started 1 month before chemotherapy and continued afterwards, making eyelashes stronger and resistant to falling out.

HMGB1 promotes hair growth via the modulation of prostaglandin metabolism

Unexpected hair growth can occur after tissue injury. The pathogenic mechanism for this phenomenon is unknown but is likely related to inflammatory mediators. One such mediator is high-mobility group box 1 (HMGB1), a ubiquitous nuclear protein that is released from cell nuclei after tissue damage. To elucidate the effect of HMGB1 on hair growth and understand its mechanism of action, we evaluated the effect of HMGB1 treatment on hair shaft elongation and on mRNA and protein expression in cultured human dermal papilla cells (hDPCs). HMGB1 enhanced hair shaft elongation in an ex vivo hair organ culture. In hDPCs, HMGB1 treatment significantly increased mRNA and protein expression levels of prostagladin E synthases. HMGB1 also stimulated prostaglandin E2 (PGE₂) secretion from hDPCs. Finally, blocking the receptor for advanced glycation end-products, a canonical HMGB1 receptor, inhibited HMGB1-induced PGE₂ production and hair shaft elongation. Our results suggest that HMGB1 promotes hair growth via PGE₂ secretion from hDPCs. This mechanism can explain the paradoxical phenomenon of trauma-induced hair growth. Thus, HGMB1 can be a viable therapeutic target for the treatment of alopecia.

Jarilla-Coffea extract: a natural cosmetic product that improves eyelash and eyebrow growth in women

Purpose

A combination of extracts, from two plant species, ie, Coffea arabica and Larrea divaricata (Jarilla) (ECOHAIR^®), is being successfully used in Argentina as a cosmetic for hair recovery in androgenic and areata alopecia, and for eyelash and eyebrow growth. The objectives of this prospective study were to evaluate the capacity of Jarilla–Coffea extract gel of improving hair growth in relation to thickness, appearance of new hair, and hair length in comparison with a placebo in premenopausal and postmenopausal volunteers and to identify possible signs of ocular adverse local reactions related to the application of the gel.

Volunteers and methods

An open-label, placebo-controlled, prospective study was performed in healthy premenopausal and postmenopausal women during a daily administration period of 2 months (eyebrow growth) and 3 months (eyelash growth). The thickness of hair was determined using a video microscope MedicalScope^®. The appearance of new hairs and total area with hair in eyebrow and eyelash length were quantified using a photographic record with Fotofinder^® (Germany). The number of volunteers presenting variation in growth of new hair and length were also recorded.

Results

The product significantly increased the thickness of eyebrows (20% in 80% women) and eyelashes (19.44% in 100% of women). The gel also increased the appearance of new hairs, total area with hair, and length but there was no statistical difference between treatment and placebo.

Conclusion

The gel was capable of improving growth of eyelashes and eyebrows by inducing principally hair thickening without causing local adverse effects in a high percentage of volunteers.

Annurca Apple Polyphenols Protect Murine Hair Follicles from Taxane Induced Dystrophy and Hijacks Polyunsaturated Fatty Acid Metabolism toward β-Oxidation

Chemotherapy-induced alopecia (CIA) is a common side effect of conventional chemotherapy and represents a major problem in clinical oncology. Even months after the end of chemotherapy, many cancer patients complain of hair loss, a condition that is psychologically difficult to manage. CIA disturbs social and sexual interactions and causes anxiety and depression. Synthetic drugs protecting from CIA and endowed with hair growth stimulatory properties are prescribed with caution by oncologists. Hormones, growth factors, morphogens could unwontedly protect tumour cells or induce cancer cell proliferation and are thus considered incompatible with many chemotherapy regimens. Nutraceuticals, on the contrary, have been shown to be safe and effective treatment options for hair loss. We here show that polyphenols from Malus Pumila Miller cv Annurca are endowed with hair growth promoting activity and can be considered a safe alternative to avoid CIA. In vitro, Annurca Apple Polyphenolic Extract (AAE) protects murine Hair Follicles (HF) from taxanes induced dystrophy. Moreover, in virtue of its mechanism of action, AAE is herein proven to be compatible with chemotherapy regimens. AAE forces HFs to produce ATP using mitochondrial β-oxidation, reducing Pentose Phosphate Pathway (PPP) rate and nucleotides production. As consequence, DNA replication and mitosis are not stimulated, while a pool of free amino acids usually involved in catabolic reactions are spared for keratin production. Moreover, measuring the effect exerted on Poly Unsaturated Fatty Acid (PUFA) metabolism, we prove that AAE promotes hair-growth by increasing the intracellular levels of Prostaglandins F2α (PGF2α) and by hijacking PUFA catabolites toward β-oxidation.

Fibroproliferative genes are preferentially expressed in central centrifugal cicatricial alopecia

BACKGROUND

Central centrifugal cicatricial alopecia (CCCA) is a primary cicatricial alopecia that most commonly affects women of African descent. Like CCCA, fibroproliferative disorders (FPDs) such as keloids, atherosclerosis, and fibroids are characterized by low-grade inflammation and irritation, resulting in end-stage fibrosis.

OBJECTIVE

We sought to determine whether fibroproliferative genes were up-regulated in patients with CCCA.

METHODS

A total of 5 patients with biopsy-proven CCCA were recruited for this study. Two scalp biopsy specimens were obtained from each patient; 1 from CCCA-affected vertex scalp and 1 from the unaffected occipital scalp. Microarray analysis was performed to determine the differential gene expression patterns.

RESULTS

There was an upregulation of genes implicated in FPDs in patients with CCCA. Specifically, we noted increased expression of platelet derived growth factor gene (PDGF), collagen I gene (COL I), collagen III gene (COL III), matrix metallopeptidase 1 gene (MMP1), matrix metallopeptidase 2 gene (MMP2), matrix metallopeptidase 7 gene (MMP7), and matrix metallopeptidase 9 gene (MMP9) in affected scalp compared with in unaffected scalp. Significant overlap in the canonic pathways was noted between patients with CCCA and patients with both atherosclerosis and hepatic fibrosis (P < .001).

LIMITATIONS

Small sample size and the use of whole skin tissue for analysis.

CONCLUSION

We have identified the upregulation of critical genes implicated in FPDs in the gene expression profile of patients with CCCA. These findings may help identify future therapeutic targets for this otherwise difficult-to-treat condition.

Therapeutic potential of bimatoprost for the treatment of eyebrow hypotrichosis

Eyebrows serve as a key feature of the face and have many roles, including cosmetic appearance and social communication. Eyebrow hypotrichosis, which refers to reduction or absence of the eyebrow hair, could be a major problem that leads to negative functional, psychological, and social consequences. Bimatoprost is an ophthalmic prostamide analog that is approved by the United States Food and Drug Administration for the treatment of eyelash hypotrichosis. Its proposed mechanism is stimulation of the prostaglandin receptor in dermal papilla and melanocyte, thus leading to a prolonged anagen phase and increased melanogenesis. The hair follicle then increases in thickness, length, and darkness. The efficacy of bimatoprost for the treatment of eyebrow hypotrichosis has been supported by well-controlled studies. Bimatoprost, which is noninvasive, effective, and well tolerated, is worth considering as a treatment option for eyebrow hypotrichosis.

Efficacy of topical latanoprost versus minoxidil and betamethasone valerate on the treatment of alopecia areata

BACKGROUND

Alopecia areata (AA) is one of the most common causes of localized hair loss. There is no universally proven therapy that induces and sustains remission of hair growth in AA.

OBJECTIVE

To compare the efficacy and safety of topical latanoprost, minoxidil and betamethasone valerate on hair growth in patients with AA.

PATIENTS AND METHODS

Hundred patients with AA classified into five groups of 20 treated with: Group I, latanoprost 0.1% lotion; Group II, minoxidil 5% lotion; Group III, betamethasone valerate 0.1% solution; Group IV, combination of latanoprost lotion and betamethasone valerate solution and Group V, a vehicle lotion control group.

RESULTS

There was a statistically significant improvement in all therapeutic groups when compared with control group and reduction of severity of alopecia tool score of scalp and beard before and after treatment for all therapeutic groups.

CONCLUSION

Latanoprost, minoxidil and betamethasone valerate are effective and safe in the treatment of patchy AA. The use of latanoprost added to the therapeutic efficacy of topical betamethasone valerate in the treatment of AA and could be an effective adjunctive topical therapy for AA.

Therapeutic Efficacy of a Combination Therapy of Topical 17α-Estradiol and Topical Minoxidil on Female Pattern Hair Loss: A Noncomparative, Retrospective Evaluation

BACKGROUND

A variety of agents have been used to treat female pattern hair loss (FPHL), including topical minoxidil, topical 17α-estradiol, oral anti-androgen agents, and mineral supplements. Compared with these single agent regimens, combination therapies could be a better therapeutic option in expectation of superior treatment outcome.

OBJECTIVE

This study was designed to determine the efficacy of a combination therapy consisting of topical 0.025% 17α-estradiol and 3% minoxidil in Korean patients with FPHL.

METHODS

Therapeutic efficacy was evaluated in 34 women who applied topical 0.025% 17α-estradiol and 3% minoxidil once daily for more than 6 months. Phototrichogram analysis was performed before and after therapy. The efficacy was evaluated with respect to total hair count, hair caliber (as assessed by phototrichogram analysis), and photographic assessment.

RESULTS

Total hair count and hair caliber both increased from baseline to 6 months in patients treated with the combination therapy of topical 0.025% 17α-estradiol and 3% minoxidil (p<0.001). Photographic assessment also revealed significant disease improvement, thus supporting the therapeutic efficacy.

CONCLUSION

A combination therapy consisting of topical 0.025% 17α-estradiol and 3% minoxidil can be tried as an effective treatment for FPHL.

Identification of genes and proteins associated with anagen wool growth

Identifying genes of major effect for wool growth would offer strategies for improving the quality and increasing the yield of fine wool. In this study, we employed the Agilent Sheep Gene Expression Microarray and proteomic technology to investigate the gene expression patterns of body side skin (more wool growing) in Aohan fine wool sheep (a Chinese indigenous breed) in comparison with groin skin (no wool growing) at the anagen stage of the wool follicle. A microarray study revealed that 4772 probes were differentially expressed, including 2071 upregulated and 2701 downregulated probes, in the comparisons of body side skin vs. groin skin (S/G). The microarray results were verified by means of quantitative PCR. A total of 1099 probes were assigned to unique genes/transcripts. The number of distinct genes/transcripts (annotated) was 926, of which 352 were upregulated and 574 were downregulated. In S/G, 13 genes were upregulated by more than 10 fold, whereas 60 genes were downregulated by more than 10 fold. Further analysis revealed that the majority of the genes possibly related to the wool growth could be assigned to categories including regulation of cell division, intermediate filament, cytoskeletal part and growth factor activity. Several potential gene families may participate in hair growth regulation, including fibroblast growth factors, transforming growth factor-β, WNTs, insulin-like growth factor, vascular endothelial growth factors and so on. Proteomic analysis also revealed 196 differentially expressed protein points, of which 121 were identified as single protein points.

Mechanism of action of herbs and their active constituents used in hair loss treatment

This article discusses the mechanisms via topically applied products containing herbs and their active constituents affect the hair growth process. It was reported that the mechanisms involving (1) insulin-like growth factor-I (IGF-I), (2) vascular endothelial growth factor (VEGF), (3) epidermal growth factor (EGF), (4) fibroblast growth factor 2 (FGF-2), (5) endothelial nitric oxide synthase (eNOS), (6) Wnt/β-catenin signalling pathway, (7) prostaglandin E (PGE), (8) prostaglandin F (PGF) stimulate hair growth, whereas the mechanisms engaging (1) 5α-reductase and dihydrotestosterone (DHT), (2) transforming growth factor beta (TGF-β), (3) fibroblast growth factor 5 (FGF-5), (4) prostaglandin D₂ (PGD₂) inhibit hair growth. The knowledge summarized in the paper may be an inspiration to create new preparations for the treatment of hair loss.

The Modulatable Stem Cell Niche: Tissue Interactions during Hair and Feather Follicle Regeneration

Hair and feathers are unique because (1) their stem cells are contained within a follicle structure, (2) they undergo cyclic regeneration repetitively throughout life, (3) regeneration occurs physiologically in healthy individuals and (4) regeneration is also induced in response to injury. Precise control of this cyclic regeneration process is essential for maintaining the homeostasis of living organisms. While stem cells are regulated by the intra-follicle-adjacent micro-environmental niche, this niche is also modulated dynamically by extra-follicular macro-environmental signals, allowing stem cells to adapt to a larger changing environment and physiological needs. Here we review several examples of macro-environments that communicate with the follicles: intradermal adipose tissue, innate immune system, sex hormones, aging, circadian rhythm and seasonal rhythms. Related diseases are also discussed. Unveiling the mechanisms of how stem cell niches are modulated provides clues for regenerative medicine. Given that stem cells are hard to manipulate, focusing translational therapeutic applications at the environments appears to be a more practical approach.

Advances in Understanding Hair Growth

In this short review, I introduce an integrated vision of human hair follicle behavior and describe opposing influences that control hair follicle homeostasis, from morphogenesis to hair cycling. The interdependence and complementary roles of these influences allow us to propose that the hair follicle is a true paradigm of a "Yin Yang" type, that is a cold/slow-hot/fast duality. Moreover, a new promising field is emerging, suggesting that glycans are key elements of hair follicle growth control.

The effect of parathyroid hormones on hair follicle physiology: implications for treatment of chemotherapy-induced alopecia

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) influence hair follicles through paracrine and intracrine routes. There is significant evidence that PTH and PTHrP influence the proliferation and differentiation of hair follicle cells. The PTH/PTHrP receptor signalling plays an important role in the hair follicle cycle and may induce premature catagen-telogen transition. Transgenic mice with an overexpression or blockade (PTH/PTHrP receptor knockout mice) of PTHrP activity revealed impaired or increased hair growth, respectively. Some findings also suggest that PTHrP may additionally influence the hair cycle by inhibiting angiogenesis. Antagonists of the PTH/PTHrP receptor have been shown to stimulate proliferation of hair follicle cells and hair growth. A hair-stimulating effect of a PTH/PTHrP receptor antagonist applied topically to the skin has been observed in hairless mice, as well as in mice treated with cyclophosphamide. These data indicate that the PTH/PTHrP receptor may serve as a potential target for new (topical) hair growth-stimulating drugs, especially for chemotherapy-induced alopecia.

Biology of the eyelash hair follicle: an enigma in plain sight

Because of their crucial impact on our perception of beauty, eyelashes constitute a prime target for the cosmetic industry. However, when compared with other hair shafts and the mini-organs that produce them [eyelash hair follicles (ELHFs)], knowledge on the biology underlying growth and pigmentation of eyelashes is still rudimentary. This is due in part to the extremely restricted availability of human ELHFs for experimental study, underappreciation of their important sensory and protective functions and insufficient interest in understanding why they are distinct from scalp hair follicles (HFs) (e.g. ELHFs produce shorter hair shafts, do not possess an arrector pili muscle, have a shorter hair cycle and undergo greying significantly later than scalp HFs). Here we synthesize the limited current knowledge on the biology of ELHFs, in humans and other species, their role in health and disease, the known similarities with and differences from other HF populations, and their intrinsic interethnic variations. We define major open questions in the biology of these intriguing mini-organs and conclude by proposing future research directions. These include dissecting the molecular and cellular mechanisms that underlie trichomegaly and the development of in vitro models in order to interrogate the distinct molecular controls of ELHF growth, cycling and pigmentation and to probe novel strategies for the therapeutic and cosmetic manipulation of ELHFs beyond prostaglandin receptor stimulation.

Bioactivation of loxoprofen to a pharmacologically active metabolite and its disposition kinetics in human skin

Loxoprofen (LX) is a prodrug-type non-steroidal anti-inflammatory drug which is used not only as an oral drug but also as a transdermal formulation. As a pharmacologically active metabolite, the trans-alcohol form of LX (trans-OH form) is generated after oral administration to humans. The objectives of this study were to evaluate the generation of the trans-OH form in human in vitro skin and to identify the predominant enzyme for its generation. In the permeation and metabolism study using human in vitro skin, both the permeation of LX and the formation of the trans-OH form increased in a time- and dose-dependent manner after the application of LX gel to the skin. In addition, the characteristics of permeation and metabolism of both LX and the trans-OH form were examined by a mathematical pharmacokinetic model. The K_m value was calculated to be 10.3 mm in the human in vitro skin. The predominant enzyme which generates the trans-OH form in human whole skin was identified to be carbonyl reductase 1 (CBR1) by immunodepletion using the anti-human CBR1 antibody. The results of the enzyme kinetic study using the recombinant human CBR1 protein demonstrated that the K_m and V_max values were 7.30 mm and 402 nmol/min/mg protein, respectively. In addition, it was found that no unknown metabolites were generated in the human in vitro skin. This is the first report in which LX is bioactivated to the trans-OH form in human skin by CBR1. Copyright © 2015 John Wiley & Sons, Ltd.

Differential expression and functionality of ATP-binding cassette transporters in the human hair follicle

BACKGROUND

ATP-binding cassette (ABC) transporters are involved in the active transport of an extremely diverse range of substrates across biological membranes. These transporters are commonly implicated in the development of multidrug resistance and are also involved in numerous physiological and homeostatic processes, including lipid transport, cell migration and differentiation.

OBJECTIVES

To close the knowledge gap in the expression of ABC transporters in the human hair follicle (HF).

METHODS

Quantitative polymerase chain reaction (qPCR) of ABC genes and immunofluorescence microscopy analysis of cryosections of human HFs.

RESULTS

By qPCR analysis, numerous members of the ABC transporter superfamily, such as ABCB1, ABCG2 and ABCA12, were found to be transcribed in full-length human scalp HFs. Immunofluorescence microscopy demonstrated that the intrafollicular protein expression of different xenobiotic ABC transporters (ABCB1, ABCC1, ABCC4, ABCG2) varies greatly, with ABCG2 expression restricted primarily to the epithelial stem cell region of the outer root sheath (bulge), whereas expression of ABCB1, ABCC1 and ABCC4 was more widespread. Lipid transporters ABCA1, ABCA12 and ABCA4 were almost uniformly expressed throughout the HF epithelium. Functional ABCB1/G2 activity was demonstrated by exclusion of the substrate dye, Hoechst 33342. In the bulge, this was reversed by ABCB1 and ABCG2 inhibition.

CONCLUSIONS

These data encourage further investigation of ABC transporters as potentially important regulators of HF epithelial biology. Clinically, pharmacological modulation of the activity of selected intrafollicular ABC transporters may permit novel therapeutic interventions, such as protecting HF stem cells from chemotherapy-induced damage, counteracting cholesterol-associated hypertrichosis, and manipulating the intrafollicular prostaglandin balance in androgenetic alopecia.

Does prostaglandin D2 hold the cure to male pattern baldness?

Lipids in the skin are the most diverse in the entire human body. Their bioactivity in health and disease is underexplored. Prostaglandin D2 has recently been identified as a factor which is elevated in the bald scalp of men with androgenetic alopecia (AGA) and has the capacity to decrease hair lengthening. An enzyme which synthesizes it, prostaglandin D2 synthase (PTGDS or lipocalin-PGDS), is hormone responsive in multiple other organs. PGD2 has two known receptors, GPR44 and PTGDR. GPR44 was found to be necessary for the decrease in hair growth by PGD2 . This creates an exciting opportunity to perhaps create novel treatments for AGA, which inhibit the activity of PTGDS, PGD2 or GPR44. This review discusses the current knowledge surrounding PGD2 , and future steps needed to translate these findings into novel therapies for patients with AGA.

Identification of skin-expressed genes possibly associated with wool growth regulation of Aohan fine wool sheep

Background

Sheep are valuable resources for the animal fibre industry. Therefore, identifying genes which regulate wool growth would offer strategies for improving the quality of fine wool. In this study, we employed Agilent sheep gene expression microarray and proteomic technology to compare the gene expression patterns of the body side (hair-rich) and groin (hairless) skins of Aohan fine wool sheep (a Chinese indigenous breed).

Results

Comparing the body side to the groin skins (S/G) of Aohan fine wool sheep, the microarray study revealed that 1494 probes were differentially expressed, including 602 more highly expressed and 892 less highly expressed probes. The microarray results were verified by means of quantitative PCR. Cluster analysis could distinguish the body side skin and the groin skin. Based on the Database for Annotation, Visualization and Integrated Discovery (DAVID), 38 of the differentially expressed genes were classified into four categories, namely regulation of receptor binding, multicellular organismal process, protein binding and macromolecular complex. Proteomic study revealed that 187 protein spots showed significant (p < 0.05) differences in their respective expression levels. Among them, 46 protein entries were further identified by MALDI-TOF/MS analyses.

Conclusions

Microarray analysis revealed thousands of differentially expressed genes, many of which were possibly associated with wool growth. Several potential gene families might participate in hair growth regulation. Proteomic analysis also indentified hundreds of differentially expressed proteins.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-014-0144-1) contains supplementary material, which is available to authorized users.

Characterization of prostaglandin F2α receptors in human eyelids

PURPOSE

Elongation, thickening, and crowding of eyelashes are commonly seen after topical use of prostaglandin analog eyedrops for glaucoma treatment. The purpose of this study was to demonstrate the presence and characterize the location of prostaglandin analog F2α receptors (PGF2α) in human hair follicles.

METHODS

In this observational clinical laboratory study, excised eyelid specimens following eyelid surgery were studied. Resected portions of eyelids were submitted for histopathologic evaluation. For immunohistochemistry evaluation, a polyclonal antibody directed against PGF2α was purchased from Cayman Chemical. The staining procedure was carried out on an automatic stainer.

RESULTS

Out of 26 patients recruited, final analysis was conducted on 17 eyes of 15 patients. There were 10 men and 5 women (mean age 77 ± 14 years). Staining was detected only in hair follicles in the anagen stage (37 slices). No variation in pattern, distribution, or intensity of immunostaining was noted among sections of different individuals. Only the bulb and stem of the hair follicle stained positive. In the bulb, the strongest staining occurred in the matricular cells and in the inner sheath layer. In the stem, the strongest staining occurred in the Huxley layer of the inner sheath.

CONCLUSIONS

This immunohistologic study found that PGF2α receptors were located predominantly in the inner root sheath of the bulb and stem of eyelashes and expressed only in eyelashes in the anagen phase.

The action of prostaglandins on ciliary hypertrichosis: a case report of pachydermoperiostosis

Pachydermoperiostosis or primary hypertropic osteoarthropathy is a rare hereditary disorder that was first described in 1868. It is characterized by digital clubbing, pachydermia (thickening of the facial skin and/or scalp), and periostosis (swelling of periarticular tissue and subperiosteal new bone formation). We report a case of a patient with the complete form of the disease, and with a unique appearance of the hair shaft and eyelashes. The authors propose a possible mechanism to justify the abnormalities observed in the patient's hair shafts regarding the metabolism of prostaglandins and its relationship with the hair follicle physiological cycle.

Hair curvature: a natural dialectic and review

Although hair forms (straight, curly, wavy, etc.) are present in apparently infinite variations, each fibre can be reduced to a finite sequence of tandem segments of just three types: straight, bent/curly, or twisted. Hair forms can thus be regarded as resulting from genetic pathways that induce, reverse or modulate these basic curvature modes. However, physical interconversions between twists and curls demonstrate that strict one-to-one correspondences between them and their genetic causes do not exist. Current hair-curvature theories do not distinguish between bending and twisting mechanisms. We here introduce a multiple papillary centres (MPC) model which is particularly suitable to explain twisting. The model combines previously known features of hair cross-sectional morphology with partially/completely separated dermal papillae within single follicles, and requires such papillae to induce differential growth rates of hair cortical material in their immediate neighbourhoods. The MPC model can further help to explain other, poorly understood, aspects of hair growth and morphology. Separate bending and twisting mechanisms would be preferentially affected at the major or minor ellipsoidal sides of fibres, respectively, and together they exhaust the possibilities for influencing hair-form phenotypes. As such they suggest dialectic for hair-curvature development. We define a natural-dialectic (ND) which could take advantage of speculative aspects of dialectic, but would verify its input data and results by experimental methods. We use this as a top-down approach to first define routes by which hair bending or twisting may be brought about and then review evidence in support of such routes. In particular we consider the wingless (Wnt) and mammalian target of rapamycin (mTOR) pathways as paradigm pathways for molecular hair bending and twisting mechanisms, respectively. In addition to the Wnt canonical pathway, the Wnt/Ca(2+) and planar cell polarity (PCP) pathways, and others, can explain many alternatives and specific variations of hair bending phenotypes. Mechanisms for hair papilla budding or its division by bisection or fission can explain MPC formation. Epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial (MET) transitions, acting in collaboration with epithelial-mesenchymal communications are also considered as mechanisms affecting hair growth and its bending and twisting. These may be treated as sub-mechanisms of an overall development from neural-crest stem cell (NCSC) lineages to differentiated hair follicle (HF) cell types, thus providing a unified framework for hair growth and development.

Hair-Loss Preventing Effect of Grateloupia elliptica

This study was conducted to evaluate the effect of Grateloupia elliptica, a seaweed native to Jeju Island, Korea, on the prevention of hair loss. When immortalized rat vibrissa dermal papilla cells were treated with extract of G. elliptica, the proliferation of dermal papilla cells significantly increased. In addition, the G. elliptica extract significantly inhibited the activity of 5α-reductase, which converts testosterone to dihydrotestosterone (DHT), a main cause of androgenetic alopecia. On the other hand, the G. elliptica extract promoted PGE2 production in HaCaT cells in a dose-dependent manner. The G. elliptica extract exhibited particularly high inhibitory effect on LPS-stimulated IL-12, IL-6, and TNF-α production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. The G. elliptica extract also showed inhibitory activity against Pityrosporum ovale, a main cause of dandruff. These results suggest that G. elliptica extract has the potential to treat alopecia via the proliferation of dermal papilla, 5α-reductase inhibition, increase of PGE2 production, decrease of LPS-stimulated pro-inflammatory cytokines and inhibitory activity against Pityrosporum ovale.

Skin graft hypertrichosis associated with prostaglandin analog in the treatment of glaucoma

Prostaglandin analogs are commonly used in the treatment of glaucoma. They are a safe and effective treatment associated with few side effects. Common local side effects include conjunctival hyperemia, iris pigmentation, and eyelash hypertrichosis. The authors present a case of a patient using travoprost treatment for primary open-angle glaucoma, who underwent excision of a lower eyelid basal cell carcinoma and reconstruction with an upper eyelid tarsoconjunctival flap and overlying skin graft. The patient developed hypertrichosis of the skin graft attributable to prostaglandin analog use.

New investigational drugs for androgenetic alopecia

INTRODUCTION

Androgenetic alopecia (AGA) is the most common form of hair loss, however current treatment options are limited and moderately effective. In the past few years, there has been an increased interest in deciphering the molecular mechanisms responsible for this disorder, which has opened the possibility of novel treatments that promise to not only stimulate hair growth, but also to induce formation of new hair follicles.

AREAS COVERED

The future holds more effective topical treatments with less systemic side effects (such as topical 5-alfa-reductase inhibitors), prostaglandin analogs and antagonists, medications which act through the Wnt signaling pathway, stem cells for hair regeneration, platelet-rich plasma (PRP) and more effective ways of transplanting hair. A comprehensive search was made using PubMed, GoogleScholar and Clinicaltrial.gov using different combination of key words, which included AGA treatment, new treatments for AGA, Wnt pathway, prostaglandins, PRP and stem cells for hair regrowth.

EXPERT OPINION

In the near future, treatments with topical 5-alfa-reductase inhibitors and prostaglandin agonists or antagonists are expected. More evidence is needed to verify the efficacy of PRP. Although hair follicle bioengineering and multiplication is a fascinating and promising field, it is still a long way from being available to clinicians.

Eicosanoids in skin inflammation

Eicosanoids play an integral part in homeostatic mechanisms related to skin health and structural integrity. They also mediate inflammatory events developed in response to environmental factors, such as exposure to ultraviolet radiation, and inflammatory and allergic disorders, including psoriasis and atopic dermatitis. This review article discusses biochemical aspects related to cutaneous eicosanoid metabolism, the contribution of these potent autacoids to skin inflammation and related conditions, and considers the importance of nutritional supplementation with bioactives such as omega-3 and omega-6 polyunsaturated fatty acids and plant-derived antioxidants as means of addressing skin health issues.

Prostaglandin D2 inhibits wound-induced hair follicle neogenesis through the receptor, Gpr44

Prostaglandins (PGs) are key inflammatory mediators involved in wound healing and regulating hair growth; however, their role in skin regeneration after injury is unknown. Using wound-induced hair follicle neogenesis (WIHN) as a marker of skin regeneration, we hypothesized that PGD₂ decreases follicle neogenesis. PGE₂ and PGD₂ were elevated early and late respectively during wound healing. The levels of WIHN, lipocalin-type prostaglandin D₂ synthase (Ptgds) and its product PGD₂ each varied significantly among background strains of mice after wounding and all correlated such that the highest Ptgds and PGD₂ levels were associated with the lowest amount of regeneration. Additionally, an alternatively spliced transcript variant of Ptgds missing exon 3 correlated with high regeneration in mice. Exogenous application of PGD₂ decreased WIHN in wild type mice and PGD₂ receptor Gpr44 null mice showed increased WIHN compared to strain-matched control mice. Furthermore, Gpr44 null mice were resistant to PGD₂-induced inhibition of follicle neogenesis. In all, these findings demonstrate that PGD₂ inhibits hair follicle regeneration through the Gpr44 receptor and imply that inhibition of PGD₂ production or Gpr44 signaling will promote skin regeneration.

The prostamide-related glaucoma therapy, bimatoprost, offers a novel approach for treating scalp alopecias

Balding causes widespread psychological distress but is poorly controlled. The commonest treatment, minoxidil, was originally an antihypertensive drug that promoted unwanted hair. We hypothesized that another serendipitous discovery, increased eyelash growth side-effects of prostamide F(2α)-related eyedrops for glaucoma, may be relevant for scalp alopecias. Eyelash hairs and follicles are highly specialized and remain unaffected by androgens that inhibit scalp follicles and stimulate many others. Therefore, we investigated whether non-eyelash follicles could respond to bimatoprost, a prostamide F(2α) analog recently licensed for eyelash hypotrichosis. Bimatoprost, at pharmacologically selective concentrations, increased hair synthesis in scalp follicle organ culture and advanced mouse pelage hair regrowth in vivo compared to vehicle alone. A prostamide receptor antagonist blocked isolated follicle growth, confirming a direct, receptor-mediated mechanism within follicles; RT-PCR analysis identified 3 relevant receptor genes in scalp follicles in vivo. Receptors were located in the key follicle regulator, the dermal papilla, by analyzing individual follicular structures and immunohistochemistry. Thus, bimatoprost stimulates human scalp follicles in culture and rodent pelage follicles in vivo, mirroring eyelash behavior, and scalp follicles contain bimatoprost-sensitive prostamide receptors in vivo. This highlights a new follicular signaling system and confirms that bimatoprost offers a novel, low-risk therapeutic approach for scalp alopecias.

Prostaglandin D2 inhibits hair growth and is elevated in bald scalp of men with androgenetic alopecia

Testosterone is necessary for the development of male pattern baldness, known as androgenetic alopecia (AGA); yet, the mechanisms for decreased hair growth in this disorder are unclear. We show that prostaglandin D(2) synthase (PTGDS) is elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with AGA. The product of PTGDS enzyme activity, prostaglandin D(2) (PGD(2)), is similarly elevated in bald scalp. During normal follicle cycling in mice, Ptgds and PGD(2) levels increase immediately preceding the regression phase, suggesting an inhibitory effect on hair growth. We show that PGD(2) inhibits hair growth in explanted human hair follicles and when applied topically to mice. Hair growth inhibition requires the PGD(2) receptor G protein (heterotrimeric guanine nucleotide)-coupled receptor 44 (GPR44), but not the PGD(2) receptor 1 (PTGDR). Furthermore, we find that a transgenic mouse, K14-Ptgs2, which targets prostaglandin-endoperoxide synthase 2 expression to the skin, demonstrates elevated levels of PGD(2) in the skin and develops alopecia, follicular miniaturization, and sebaceous gland hyperplasia, which are all hallmarks of human AGA. These results define PGD(2) as an inhibitor of hair growth in AGA and suggest the PGD(2)-GPR44 pathway as a potential target for treatment.

Hormones and the pilosebaceous unit

Hormones can exert their actions through endocrine, paracrine, juxtacrine, autocrine and intracrine pathways. The skin, especially the pilosebaceous unit, can be regarded as an endocrine organ meanwhile a target of hormones, because it synthesizes miscellaneous hormones and expresses diverse hormone receptors. Over the past decade, steroid hormones, phospholipid hormones, retinoids and nuclear receptor ligands as well as the so-called stress hormones have been demonstrated to play pivotal roles in controlling the development of pilosebaceous units, lipogenesis of sebaceous glands and hair cycling. Among them, androgen is most extensively studied and of highest clinical significance. Androgen-mediated dermatoses such as acne, androgenetic alopecia and seborrhea are among the most common skin disorders, with most patients exhibiting normal circulating androgen levels. The "cutaneous hyperandrogenism" is caused by in stiu overexpression of the androgenic enzymes and hyperresponsiveness of androgen receptors. Regulation of cutaneous steroidogenesis is analogous to that in gonads and adrenals. More work is needed to explain the regional difference within and between the androgn-mediated dermatoses. The pilosebaceous unit can act as an ideal model for studies in dermato-endocrinology.

Hair follicular expression and function of group X secreted phospholipase A2 in mouse skin

Although perturbed lipid metabolism can often lead to skin abnormality, the role of phospholipase A(2) (PLA(2)) in skin homeostasis is poorly understood. In the present study we found that group X-secreted PLA(2) (sPLA(2)-X) was expressed in the outermost epithelium of hair follicles in synchrony with the anagen phase of hair cycling. Transgenic mice overexpressing sPLA(2)-X (PLA2G10-Tg) displayed alopecia, which was accompanied by hair follicle distortion with reduced expression of genes related to hair development, during a postnatal hair cycle. Additionally, the epidermis and sebaceous glands of PLA2G10-Tg skin were hyperplasic. Proteolytic activation of sPLA(2)-X in PLA2G10-Tg skin was accompanied by preferential hydrolysis of phosphatidylethanolamine species with polyunsaturated fatty acids as well as elevated production of some if not all eicosanoids. Importantly, the skin of Pla2g10-deficient mice had abnormal hair follicles with noticeable reduction in a subset of hair genes, a hypoplasic outer root sheath, a reduced number of melanin granules, and unexpected up-regulation of prostanoid synthesis. Collectively, our study highlights the spatiotemporal expression of sPLA(2)-X in hair follicles, the presence of skin-specific machinery leading to sPLA(2)-X activation, a functional link of sPLA(2)-X with hair follicle homeostasis, and compartmentalization of the prostanoid pathway in hair follicles and epidermis.

Bimatoprost in the treatment of eyelash hypotrichosis

Eyelashes hypotrichosis is a condition indicated by an inadequate amount of eyelashes. Hypertrichosis of eyelashes, characterized by excessive eyelash growth, is a regular phenomenon associated with ophthalmic prostaglandin and prostamide analogs. Recently, the US Food and Drug Administration approved Latisse((R)) (bimatoprost 0.03% solution), identical to the ophthalmic solution for glaucoma treatment, for increasing eyelash length, thickness and darkness in patients with hypotrichosis of the eyelashes. When prostaglandin and prostamide analogs interact with the prostanoid receptors in the hair follicle, this most likely stimulates the resting follicles (telogen phase) to growing follicles (anagen phase). Prostaglandin and prostamide analogs may also prolong the anagen phase of eyelashes, leading to an increase of eyelash length. Although bimatoprost is effective in promoting increased growth of healthy eyelashes and adnexal hairs, its effectiveness in patients with eyelash alopecia areata is debatable and its protective effect is not yet studied in patients with eyelash loss secondary to radiation or chemotherapy. Bimatoprost is generally safe when applied to the base of the eyelashes at the lid margin with minimum side effects. However, other ocular or systemic side effects associated with ophthalmic prostaglandin and prostamide analogs may occur when instilled on the surface of the eye, and patients must be informed and monitored.

Identification of transcriptional targets of Wnt/beta-catenin signaling in dermal papilla cells of human scalp hair follicles: EP2 is a novel transcriptional target of Wnt3a

BACKGROUND

Recent studies showed that Wnt signaling through the beta-catenin pathway (canonical Wnt signaling) act on mouse dermal papilla cells (DPCs) enabling hair follicles to keep growing.

OBJECTIVE

To investigate whether human DPCs respond to canonical Wnt signaling and, if so, to identify target genes of Wnt/beta-catenin pathway.

METHODS

Cultured human DPCs were transiently transfected with the beta-catenin responsive TCF reporter plasmid (pTopflash) and corresponding negative control reporter (pFopflash) to assess the activity of beta-catenin signaling by Wnt3a (one of the canonical Wnts). Immunofluorescence staining was also performed to localize beta-catenin in the presence or absence of Wnt3a. Microarray was carried out using Affymetrix gene chips. RT-PCR analysis and immunoblot were employed to verify microarray data. Cyclic AMP (cAMP) levels were measured using EIA assay after Wnt3a and PGE2 treatment in DPCs.

RESULTS

Wnt3a significantly stimulated the transcriptional activity of pTopflash but not pFopflash. In line with this, we identified a number of genes that are regulated by Wnt3a. Some of the differently expressed genes including EP2 were confirmed by RT-PCR analysis. Immunoblot further confirmed that EP2 protein is indeed increased by Wnt3a. DPCs pretreated with Wnt3a showed higher responsiveness to PGE2 as measured by cAMP levels.

CONCLUSIONS

Elucidation of the role of Wnt3a-regulated genes identified in this study including EP2 would help our understanding of hair-induction and maintenance of anagen phase.