Hepatocyte growth factor (HGF) activator expressed in hair follicles is involved in in vitro HGF-dependent hair follicle elongation

Anti-Hair Loss Effect of Veratric Acid on Dermal Papilla Cells

The activation of hair follicle dermal papilla cells (HFDPCs), a critical target of hair loss relief, can be achieved through the upregulation of proliferation, the stimulation of hair inducibility, and the inhibition of cellular senescence. Veratric acid (VA) is a major benzoic acid found in fruits and vegetables. The biological activity of VA on HFDPCs remains to be elucidated. In this study, we investigated the capacity of VA for hair loss mitigation. An MTT assay, Ki67 staining, quantitative RT-PCR (qRT-PCR), and a Western blot analysis were performed to confirm the proliferative effect of VA. Hair inductivity was determined through a cell aggregation assay and ALP staining. Annexin V/PI staining was performed to confirm the anti-apoptotic effect of VA. The inhibitory effect of VA on cellular senescence was confirmed by a β-galactosidase (β-gal) assay and qRT-PCR using replicative senescence and oxidative stress-induced senescence models. As a result, VA dose-dependently upregulated the proliferation of HFDPCs, the expression of growth factors, and β-catenin protein levels. VA also dose-dependently increased ALP activity and cell aggregation and decreased apoptotic cells through the regulation of BCL2 and BAX expression. Moreover, VA reduced β-gal activity and the senescence-associated secretory phenotype (SASP) in a dose-dependent manner in senescent HFDPCs. These findings suggest that VA may serve as a potential therapeutic agent for alleviating hair loss by targeting multiple pathways involved in HFDPC activation.

Imprinted Dlk1-Gtl2 cluster miRNAs are potential epigenetic regulators of lamb fur quality

BACKGROUND

Tan and Hu sheep are well-known local breeds in China, producing lamb fur with unique ornamental and practical values highly appreciated by consumers worldwide. Fur quality is optimal at one month of age and gradually declines with time. Despite active research on its genetic mechanism using transcriptomic and whole genome bisulfite sequencing analysis, the main effective gene locus has not been found, and its regulatory mechanism is still unclear, which limits the breeding and improvement of fur traits.

RESULTS

Scapular skin samples from newborn (1-month old) and adult (24-month old) Tan sheep were utilized for small ribonucleic acid (RNA) sequencing Principal Component Analysis (PCA) showed that the newborn and adult groups were completely separated. Differential expression analysis of micro-RNAs (miRNAs) identified 32 up-regulated miRNAs and 48 down-regulated miRNAs in the newborn groups. All up-regulated miRNAs were located in the imprinted. Dlk1-Gtl2 locus on chromosome 18, whereas all down-regulated miRNAs were distributed across the sheep chromosomes, without a clear pattern of positional consistency. Further, by systematically analyzing the target genes and signaling pathways of all 32 up-regulated miRNAs, we found that the PI3K-AKT signaling pathway has the potential to be targeted and regulated by most of the miRNAs in the Dlk1-Gtl2 region. In addition, we also re-analyzed miRNA sequencing data from public databases on Hu lambs (full sibling Hu lambs with high- and low-quality fur characteristics). Again, it was found that most of the up-regulated miRNAs in lambs with high-quality fur were also located in the Dlk1-Gtl2 region, whereas this patter was not present for down-regulated miRNAs.

CONCLUSION

Sequencing of miRNAs in conjunction with public databases was employed to identify miRNAs within the imprinted Dlk1-Gtl2 region on chromosome 18, suggesting their potential roles as epigenetic regulators of fur traits. Small RNAs located at the Dlk1-Gtl2 locus were identified as having the potential to systematically regulate the PI3K-AKT signaling pathway, thereby indicating the relevance of the Dlk1-Gtl2/PI3K-AKT axis in the context of fur traits. Selection of parental specific expressed imprinted genes in the process of conserving and exploiting lamb fur traits should be emphasized.

Effects of a Combination of Arginine Silicate Inositol Complex and a Novel Form of Biotin on Hair and Nail Growth in a Rodent Model

The purpose of this study was to examine the effects of a combination of inositol-stabilized arginine silicate complex (ASI) and magnesium biotinate (MgB) on hair and nail growth in an animal model. Twenty-eight female Sprague-Dawley rats (8 weeks old) were randomized into one of the following groups: (i) group (control), shaved; (ii) group (ASI), shaved + ASI (4.14 mg/rat/day); (iii) group (ASI + MgB I), shaved + ASI (4.14 mg/rat/day) + MgB (48.7 μg/rat/day); and (iv) group (ASI + MgB II), shaved + ASI (4.14 mg/rat/day) + MgB (325 μg/rat/day). On day 42, compared with the control group, while hair density (p < 0.05, p < 0.01, and p < 0.0001, respectively) and anagen ratio (p < 0.01, p < 0.01, and p < 0.001) increased in the ASI, ASI + MgB I, and ASI + MgB II groups, telogen ratio decreased (p < 0.01, p < 0.01, and p < 0.001, respectively). In the molecular analysis, VEGF, HGF, and KGF-2 increased in the ASI (p < 0.01, p < 0.01, and p < 0.05, respectively), ASI + MgB I (p < 0.0001 for all), and ASI + MgB II (p < 0.0001 for all) groups when compared to the control group. FGF-2 (p < 0.01) and IGF-1 (p < 0.001) were found to be increased in the ASI + MgB I and ASI + MgB II groups. SIRT-1 and β-catenin increased in the ASI (p < 0.05 and p < 0.01), ASI + MgB I (p < 0.001 for both), and ASI + MgB II (p < 0.0001 for both) groups. Wnt-1 increased in the ASI + MgB I (p < 0.001) and ASI + MgB II (p < 0.0001) groups. In conclusion, the combination of ASI and MgB could promote hair growth by regulating IGF-1, FGF, KGF, HGF, VEGF, SIRT-1, Wnt, and β-catenin signal pathways. It was also established that ASI did not affect nail growth, whereas the MgB combination was effective using a higher dose of biotin.

Effect of Coffee Berry Extract on Anti-Aging for Skin and Hair—In Vitro Approach

The aging process encompasses gradual and continuous changes at the cellular level that slowly accumulate with age. The signs of aging include many physiological changes in both skin and hair such as fine lines, wrinkles, age spots, hair thinning and hair loss. The aim of the current study was to investigate the anti-aging potential of coffee berry extract (CBE) on human dermal fibroblast (HDF) and hair follicle dermal papilla (HFDP) cells. Coffee berry was extracted by 50% ethanol and determined for chemical constituents by HPLC technique. Cytotoxicity of the extract was examined on both cells by MTT assay. Then, HDF cells were used to evaluate antioxidant properties by using superoxide dismutase activity (SOD) and nitric oxide inhibition as well as anti-collagenase inhibition assays. The effectiveness of anti-hair loss properties was investigated in HFDP cells by considering cell proliferation, 5α-reductase inhibition (5AR), and growth factor expression. The results showed that caffeine and chlorogenic acid were identified as major constituents in CBE. CBE had lower toxicity and cell proliferation than caffeine and chlorogenic acid on both cells. CBE showed SOD and nitric oxide inhibition activities that were higher than those of caffeine but lower than those of chlorogenic acid. Interestingly, CBE had the highest significant anti-collagenase activity, and its 5AR inhibition activity was comparable to that of chlorogenic acid, which was higher than caffeine. CBE also stimulated hair-related gene expression, especially insulin-like growth factor 1 (IGF-1), keratinocyte growth factor (KGF) and vascular endothelial growth factor (VEGF). The results confirmed that CBE provided anti-aging activity on both skin and hair cells and could be beneficial for applications in cosmeceuticals.

Hair growth-promoting effects of Camellia seed cake extract in human dermal papilla cells and C57BL/6 mice

OBJECTIVES

Camellia seed cake is a byproduct of Camellia oleifera Abel seed after oil extraction. Washing hair with Camellia seed cake extract is a traditional Chinese custom that has lasted for over one thousand years. However, the hair growth-promoting effects of Camellia seed cake extract were not investigated so far. This work examined the effects of de-saponinated Camellia seed cake extracts (DS-CSE) on hair growth, using in vitro and in vivo models.

METHODS

The studies on cell proliferation, cell cycle regulation and K⁺ channels activation effects of DS-CSE were performed on human dermal papilla cells (DPCs). Relative expression of insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and transforming growth factor-β (TGF-β1) in DPCs was determined by RT-PCR. Relative expression of ERK and AKT was determined by western blot analysis. Hair growth promoting effects was also measured in C57BL/6J mice model.

RESULTS

DS-CSE treatment significantly proliferated DPCs, relating to the increased proportion of DPCs in S and G₂ /M phases, the activation of potassium channels as well as the promoted phosphorylation of ERK and AKT in DPCs. DS-CSE treatment also significantly upregulated the mRNA levels of HGF, VEGF and IGF-1, and downregulated the mRNA level of TGF-β1. Topical application of DS-CSE promoted hair growth on shaven back mice and also upregulated the expression of VEGF in mice.

CONCLUSION

Our results demonstrated that DS-CSE exerts a hair growth promoting effect in vitro and in vivo by proliferating DPCs through the ERK and AKT signaling pathways and regulating the expression of growth factors.

The inflammatory proteome of hidradenitis suppurativa skin is more expansive than that of psoriasis vulgaris

BACKGROUND

Although hidradenitis suppurativa (HS) shares some transcriptomic and cellular infiltrate features with psoriasis, their skin proteome remains unknown.

OBJECTIVE

To define and compare inflammatory protein biomarkers of HS and psoriasis skin.

METHODS

We assessed 92 inflammatory biomarkers in HS (n = 13), psoriasis (n = 11), and control skin (n = 11) using Olink high-throughput proteomics. We also correlated HS skin and blood biomarkers using proteomics and RNA sequencing.

RESULTS

We identified 57 differentially expressed proteins (DEPs) in lesional psoriasis and 64 DEPs in lesional HS skin, compared to healthy controls. Both HS and psoriasis lesional skin demonstrated a significant upregulation of T helper 1 and T helper 17 proteins. Healthy-appearing perilesional HS skin had 63 DEPs compared to healthy controls. Nonlesional HS and psoriasis skin had 24 and 7 DEPs, respectively, compared to healthy controls. Tumor necrosis factor and 8 other proteins were significantly correlated with clinical severity in perilesional HS skin (2 cm from a nodule).

LIMITATIONS

Inclusion of only moderate-to-severe patients and the cohort size.

CONCLUSION

HS has a greater inflammatory profile and is more diffusely distributed compared with psoriasis. Proteins correlated with disease severity are potential disease mediators. Perilesional skin is comparably inflamed to lesional skin, suggesting the need to treat beyond skin nodules.

Morus alba Root Extract Induces the Anagen Phase in the Human Hair Follicle Dermal Papilla Cells

Restoring hair follicles by inducing the anagen phase is a promising approach to prevent hair loss. Hair follicle dermal papilla cells (HFDPCs) play a major role in hair growth via the telogen-to-anagen transition. The therapeutic effect of Morus alba activates β-catenin in HFDPCs, thereby inducing the anagen phase. The HFDPCs were treated with M. alba root extract (MARE) to promote hair growth. It contains chlorogenic acid and umbelliferone and is not cytotoxic to HFDPCs at a concentration of 20%. It was demonstrated that a small amount of MARE enhances growth factor secretion (related to the telogen-to-anagen transition). Activation of β-catenin was observed in MARE-treated HFDPCs, which is crucial for inducing the anagen phase. The effect of conditioned medium derived from MARE-treated HFDPCs on keratinocytes and endothelial cells was also investigated. The findings of this study demonstrate the potency of MARE in eliciting the telogen-to-anagen transition.

Hair Growth Promoting Activity of Cedrol Nanoemulsion in C57BL/6 Mice and Its Bioavailability

As the main component of Platycladus orientalis, cedrol has known germinal activity. A range of cedrol formulations have been developed to prevent hair-loss, but compliance remains key issues. In this study, we prepared cedrol nanoemulsion (CE-NE) and determined the particle size and PDI (polydispersion coefficient), investigated the hair growth activity and studied the bioavailability in vitro and in vivo. Results showed that the average particle size of CE-NE is 14.26 ± 0.16 nm, and the PDI value is 0.086 ± 0.019. In vitro drug release investigation and drug release kinetics analysis showed release profile of CE from nanoparticles demonstrates the preferred partition of CE in buffer pH 4.0, the release profile of CE-NE showed a first-order kinetics reaching around 36.7% after 6 h at 37 °C. We artificially depilated the back hair of C57BL/6 mice and compared the efficacy of a designed cedrol nanoemulsion to an existing ointment group. The hair follicles were imaged and quantified using a digital photomicrograph. The results showed that compared with the ointment, CE-NE had positive effects on hair growth, improved drug solubility. Compared with the ointment and 2% minoxidil groups, 50 mg/mL CE-NE led to more robust hair growth. Pharmacokinetics analysis showed that the AUC0-t of CE-NE was 4-fold higher than that of the ointment group, confirming that the bioavailability of the nanoemulsion was greater than that of the ointment. CE-NE also significantly reduced the hair growth time of model mice and significantly increased the growth rate of hair follicles. In conclusion, these data suggest that the nanoemulsion significantly improved the pharmacokinetic properties and hair growth effects cedrol, enhancing its efficacy in vitro and in vivo.

Dermal Adipose Tissue Secretes HGF to Promote Human Hair Growth and Pigmentation

Hair follicles (HFs) are immersed within dermal white adipose tissue (dWAT), yet human adipocyte‒HF communication remains unexplored. Therefore, we investigated how perifollicular adipocytes affect the physiology of human anagen scalp HFs. Quantitative immunohistomorphometry, X-ray microcomputed tomography, and transmission electron microscopy showed that the number and size of perifollicular adipocytes declined during anagen‒catagen transition, whereas fluorescence-lifetime imaging revealed increased lipid oxidation in adipocytes surrounding the bulge and/or sub-bulge region. Ex vivo, dWAT tendentially promoted hair shaft production, and significantly stimulated hair matrix keratinocyte proliferation and HF pigmentation. Both dWAT pericytes and PREF1/DLK1⁺ adipocyte progenitors secreted HGF during human HF‒dWAT co-culture, for which the c-Met receptor was expressed in the hair matrix and dermal papilla. These effects were reproduced using recombinant HGF and abrogated by an HGF-neutralizing antibody. Laser-capture microdissection‒based microarray analysis of the hair matrix showed that dWAT-derived HGF upregulated keratin (K) genes (K27, K73, K75, K84, K86) and TCHH. Mechanistically, HGF stimulated Wnt/β-catenin activity in the human hair matrix (increased AXIN2, LEF1) by upregulating WNT6 and WNT10B, and inhibiting SFRP1 in the dermal papilla. Our study demonstrates that dWAT regulates human hair growth and pigmentation through HGF secretion, and thus identifies dWAT and HGF as important novel molecular and cellular targets for therapeutic intervention in human hair growth and pigmentation disorders.

Hair growth potential of Salvia plebeia extract and its associated mechanisms

Context: Although Salvia plebeia (SP) R. Brown (Labiatae) is known to possess various biological activities, the effects of SP on hair growth have not been elucidated.Objective: To investigate the hair growth potential of SP extract by using human dermal papilla cells (hDPCs) and C57BL/6 mice.Materials and methods: The entire SP plant sample was ground into powder and extracted with 99.9% methyl alcohol. Various concentrations of SP extract were added to hDPCs to evaluate the proliferation, migration, and factors related to hair growth and cycling. Effect of topical SP administration on hair regrowth was tested in vivo in male C57BL/6 mice for 21 days.Results: SP extract significantly increased the proliferation of cultured hDPCs at doses of 15.6 and 31.3 μg/mL compared to control group by 123% and 132%, respectively. Expression of hepatocyte growth factor increased while the level of TGF-β1 and SMAD2/3 decreased when treated with SP extract. At the molecular level, the extract activated Wnt/β-catenin signalling by raising β-catenin and phospho-GSK3β expression. SP extract also exerted anti-apoptotic and proliferative effects in hDPCs by increasing the Bcl-2/Bax ratio and activating cell proliferation-related proteins, ERK and Akt. Finally, the extract caused an induction of the anagen phase leading to significantly enhanced hair growth in treated male mice.Discussion and conclusion: Our results indicate that SP extract has the capacity to activate hDPCs into a proliferative state to promote hair growth. Further research is necessary to determine the bioactive components and their mechanisms of action responsible for SP-related hair growth effect.

A randomized, double-blind, vehicle-controlled clinical study of hair regeneration using adipose-derived stem cell constituent extract in androgenetic alopecia

Accumulating evidence suggests that adipose-derived stem cell constituent extract (ADSC-CE) helps hair regrowth in patients with androgenetic alopecia (AGA). However, the effects of ADSC-CE have not been demonstrated in a randomized, double-blind, vehicle-controlled clinical trial. In this randomized, double-blind, vehicle-controlled clinical trial, 38 patients (29 men) with AGA were assigned to an intervention group (IG), with twice-daily self-application of the ADSC-CE topical solution over the scalp with fingers, or to a control group (CG). Changes in hair count and thickness at 16 weeks from the baseline were evaluated using a phototrichogram. Overall, 34 (89%) patients (mean age, 45.3 years) completed the study. The phototrichogram at week 8 showed more increase in hair count in the IG than in the CG, and intergroup differences in the change of hair count remained significant until week 16 with overall changes of 28.1% vs 7.1%, respectively. Similarly, a significant improvement in hair diameter was observed in the IG (14.2%) after 16 weeks when compared with hair diameter in the CG (6.3%). Our findings suggest that the application of the ADSC-CE topical solution has enormous potential as an alternative therapeutic strategy for hair regrowth in patients with AGA, by increasing both hair density and thickness while maintaining adequate treatment safety.

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

BACKGROUND

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

RESULTS

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

CONCLUSION

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

Effect of Cinnamomum osmophloeum Kanehira Leaf Aqueous Extract on Dermal Papilla Cell Proliferation and Hair Growth

In this study, we explored the effect of the water extract of Cinnamomum osmophloeum Kanehira (COK) leaves on hair growth by in vitro and in vivo assays. Using an in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, it was found that the proliferation of rat vibrissae and human hair dermal papilla cells (hDPCs) was significantly enhanced by the COK leaf extract treatment. As determined by quantitative real-time polymerase chain reaction (RT-PCR), the messenger RNA (mRNA) levels of some hair growth–related factors including vascular endothelial growth factor, keratinocyte growth factor (KGF), and transforming growth factor-β2 were found to be higher in the cultured hDPCs exposed to COK leaf extract than those in the untreated control group. In the hair-depilated C57BL/6 mouse model, the stimulation of hair growth was demonstrated in the group of COK leaf extract treatment. Both photographical and histological observations revealed the promotion of the anagen phase in the hair growth cycle by the COK leaf extract in the C57BL/6 mice. Finally, the ultra performance liquid chromatography (UPLC) showed that the COK extract contained mostly cinnamic aldehyde and a small amount of cinnamic acid. The results suggest that the COK leaf extract may find use for the treatment of hair loss.

Conventional and novel stem cell based therapies for androgenic alopecia

The prevalence of androgenic alopecia (AGA) increases with age and it affects both men and women. Patients diagnosed with AGA may experience decreased quality of life, depression, and feel self-conscious. There are a variety of therapeutic options ranging from prescription drugs to non-prescription medications. Currently, AGA involves an annual global market revenue of US$4 billion and a growth rate of 1.8%, indicating a growing consumer market. Although natural and synthetic ingredients can promote hair growth and, therefore, be useful to treat AGA, some of them have important adverse effects and unknown mechanisms of action that limit their use and benefits. Biologic factors that include signaling from stem cells, dermal papilla cells, and platelet-rich plasma are some of the current therapeutic agents being studied for hair restoration with milder side effects. However, most of the mechanisms exerted by these factors in hair restoration are still being researched. In this review, we analyze the therapeutic agents that have been used for AGA and emphasize the potential of new therapies based on advances in stem cell technologies and regenerative medicine.

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.

Malva verticillata seed extracts upregulate the Wnt pathway in human dermal papilla cells

OBJECTIVE

Mesenchymal-epithelial interactions are important in controlling hair growth and the hair cycle. The β-catenin pathway of dermal papilla cells (DPCs) plays a pivotal role in morphogenesis and normal regeneration of hair follicles. Deletion of β-catenin in the dermal papilla reduces proliferation of the hair follicle progenitor cells that generate the hair shaft and induces an early onset of the catagen phase. In this study, a modulator of the Wnt/β-catenin activity was studied in oriental herb extracts on cultured human DPCs.

METHODS

The effect of Malva verticillata (M. verticillata) seeds on human DPCs was investigated by a Wnt/β-catenin reporter activity assay system (β-catenin-TCF/LEF reporter gene) and cell proliferation analysis. The synthesis of the factors related to hair growth and cycling was measured at both the mRNA and the protein level by semi-quantitative PCR and Western blot analysis, respectively.

RESULTS

An extract from M. verticillata seeds increased Wnt reporter activity in a concentration-dependent manner and also led to increased β-catenin levels in cultured human DPCs. Myristoleic acid, identified as an effective compound of M. verticillata seeds, stimulated the proliferation of DPCs in a dose-dependent manner and increased transcription levels of the downstream targets: IGF-1, KGF, VEGF and HGF. Myristoleic acid also enhanced the phosphorylation of MAPKs (Akt and p38).

CONCLUSION

Overall, the data suggest that this extract of M. verticillata seeds could be a good candidate for treating hair loss by modulating the Wnt/β-catenin pathway in DPCs.

Biomaterials for in situ tissue regeneration: development and perspectives

Biomaterials are of fundamental importance to in situ tissue regeneration, which has emerged as a powerful method to treat tissue defects. The development and perspectives of biomaterials for in situ tissue regeneration were summarized.

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.

Hepatocyte growth factor activator (HGFA): pathophysiological functions in vivo

Hepatocyte growth factor activator (HGFA) is a serine protease initially identified as a potent activator of hepatocyte growth factor/scatter factor. Hepatocyte growth factor/scatter factor is known to be critically involved in tissue morphogenesis, regeneration, and tumor progression, via its receptor, MET. In vivo, HGFA also activates macrophage-stimulating protein, which has roles in macrophage recruitment and inflammatory processes, cellular survival and wound healing through its receptor, RON. Therefore, the pericellular activity of HGFA might be an important factor regulating the activities of these multifunctional cytokines in vivo. HGFA is secreted mainly by the liver, circulates in the plasma as a zymogen (pro-HGFA), and is activated in response to tissue injury, including tumor growth. In addition, local production of pro-HGFA by epithelial, stromal or tumor cells has been reported. Although the generation of HGFA-knockout mice revealed that the role played by HGFA in normal development and physiological settings can be compensated for by other protease systems, HGFA has important roles in regeneration and initial macrophage recruitment in injured tissue in vivo. Insufficient activity of HGFA results in impaired regeneration of severely damaged mucosal epithelium, and may contribute to the progression of fibrotic lung diseases. On the other hand, deregulated excess activity of HGFA may be involved in the progression of some types of cancer.

Hepatocyte growth factor system in the mouse uterus: variation across the estrous cycle and regulation by 17-beta-estradiol and progesterone

Hepatocyte growth factor (HGF) and its receptor MET have been implicated in uterine development, pregnancy, and endometrial disorders, such as endometriosis and carcinoma. In vitro studies have shown that HGF acts as a mitogen, motogen, and morphogen on endometrial epithelial cells. However, the expression and regulation of HGF and MET in the uteri of different species remain obscure. The present study aimed to investigate the changes of HGF, MET, and HGF activator (HGFA) expression in the uterine endometrium during the estrous cycle in mice and to explore estrogen and progesterone regulation of their expression. MKI67 immunostaining was conducted to examine the association between HGF/MET expression and endometrial cell proliferation. Endometrial epithelial and stromal cells both expressed HGF, HGFA, and MET, but the cell type-specific patterns changed during the cycle. Estrogen and progesterone differentially regulated HGF, MET, and HGFA expression. Progesterone up-regulated their expression in the stroma and down-regulated their expression in the luminal epithelium, whereas 17-beta-estradiol down-regulated their expression in the glandular epithelium. The pattern of HGF/MET overall correlated with that of MKI67. In conclusion, HGF, HGFA, and MET expression in mouse uterus changes during the estrous cycle in a stage-, cell type-, and compartment-specific manner under the influence of estrogen and progesterone. HGF likely plays a role in cyclic endometrial remodeling, such as cell proliferation via autocrine/paracrine mechanisms in mouse uterus.

Methods in hair research: how to objectively distinguish between anagen and catagen in human hair follicle organ culture

The organ culture of human scalp hair follicles (HFs) is the best currently available assay for hair research in the human system. In order to determine the hair growth-modulatory effects of agents in this assay, one critical read-out parameter is the assessment of whether the test agent has prolonged anagen duration or induced catagen in vitro. However, objective criteria to distinguish between anagen VI HFs and early catagen in human HF organ culture, two hair cycle stages with a deceptively similar morphology, remain to be established. Here, we develop, document and test an objective classification system that allows to distinguish between anagen VI and early catagen in organ-cultured human HFs, using both qualitative and quantitative parameters that can be generated by light microscopy or immunofluorescence. Seven qualitative classification criteria are defined that are based on assessing the morphology of the hair matrix, the dermal papilla and the distribution of pigmentary markers (melanin, gp100). These are complemented by ten quantitative parameters. We have tested this classification system by employing the clinically used topical hair growth inhibitor, eflornithine, and show that eflornithine indeed produces the expected premature catagen induction, as identified by the novel classification criteria reported here. Therefore, this classification system offers a standardized, objective and reproducible new experimental method to reliably distinguish between human anagen VI and early catagen HFs in organ culture.

LEKTI fragments specifically inhibit KLK5, KLK7, and KLK14 and control desquamation through a pH-dependent interaction

LEKTI is a 15-domain serine proteinase inhibitor whose defective expression underlies the severe autosomal recessive ichthyosiform skin disease, Netherton syndrome. Here, we show that LEKTI is produced as a precursor rapidly cleaved by furin, generating a variety of single or multidomain LEKTI fragments secreted in cultured keratinocytes and in the epidermis. The identity of these biological fragments (D1, D5, D6, D8-D11, and D9-D15) was inferred from biochemical analysis, using a panel of LEKTI antibodies. The functional inhibitory capacity of each fragment was tested on a panel of serine proteases. All LEKTI fragments, except D1, showed specific and differential inhibition of human kallikreins 5, 7, and 14. The strongest inhibition was observed with D8-D11, toward KLK5. Kinetics analysis revealed that this interaction is rapid and irreversible, reflecting an extremely tight binding complex. We demonstrated that pH variations govern this interaction, leading to the release of active KLK5 from the complex at acidic pH. These results identify KLK5, a key actor of the desquamation process, as the major target of LEKTI. They disclose a new mechanism of skin homeostasis by which the epidermal pH gradient allows precisely regulated KLK5 activity and corneodesmosomal cleavage in the most superficial layers of the stratum corneum.

Reactive site-dependent phenotypic alterations in plasminogen activator inhibitor-1 transgenic mice

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of plasminogen activators (PAs) and plays a role in the regulation of a number of physiological processes including the degradation of extracellular matrix proteins, cell proliferation and migration, and intracellular signaling.

AIM

To characterize the effects of durable expression of a stable form of human PAI-1 and to characterize important structure-function relationships in PAI-1 in vivo.

METHODS

We developed transgenic mice lines overexpressing stable variants of human PAI-1 under the control of the murine preproendothelin-1 promoter and characterized the phenotypic alterations displayed by transgenic mice.

RESULTS

Transgenic mice expressing an active form of human PAI-1 (PAI-1-stab) display complex phenotypic abnormalities including alopecia and hepatosplenomegaly. Reactive site mutant transgenic mice expressing inactive PAI-1 exhibit complete phenotypic rescue, while transgenic mice expressing PAI-1 with reduced affinity for vitronectin manifest all of the phenotypic abnormalities present in PAI-1-stab transgenic mice.

CONCLUSIONS

The protease inhibitory activity of PAI-1 toward PAs and/or other serine proteases is necessary and sufficient to promote complex phenotypic abnormalities and mediates many of the physiological effects of PAI-1 in vivo.

Thymosin beta4 increases hair growth by activation of hair follicle stem cells

Thymosin beta4, a 43-amino acid polypeptide that is an important mediator of cell migration and differentiation, also promotes angiogenesis and wound healing. Here, we report that thymosin beta4 stimulates hair growth in normal rats and mice. A specific subset of hair follicular keratinocytes in mouse skin expresses thymosin beta4 in a highly coordinated manner during the hair growth cycle. These keratinocytes originate in the hair follicle bulge region, a niche for skin stem cells. Rat vibrissa follicle clonogenic keratinocytes, closely related, if not identical, to the bulge-residing stem cells, were isolated and their migration and differentiation increased in the presence of nanomolar concentrations of thymosin beta4. Expression and secretion of the extracellular matrix-degrading enzyme matrix metalloproteinase-2 were increased by thymosin beta4. Thus, thymosin beta4 accelerates hair growth, in part, due to its effect on critical events in the active phase of the hair follicle cycle, including promoting the migration of stem cells and their immediate progeny to the base of the follicle, differentiation, and extracellular matrix remodeling.

Identification of androgen-regulated genes in SV40-transformed human hair dermal papilla cells

BACKGROUND

Androgens are major regulators of human hair growth, which exert their effect on follicular epithelium via the mesenchyme-derived dermal papilla (DP) cells. However, very few data are available with regard to the genes regulated by androgen in DP cells.

OBJECTIVE

To investigate the differentially expressed genes by androgen in DP cells.

METHODS

Human hair DP cells were cultured and transformed with SV40 T antigen. Using cDNA representational difference analysis, androgen-regulated genes in SV40-transformed dermal papilla (SDP) cells were identified.

RESULTS

SDP cells revealed extended lifespan as compared with primary cultured DP cells. SDP cells expressed androgen receptor (AR) and showed androgen responsiveness. cDNA representational difference analysis followed by Northern blot analysis showed that heat shock cognate protein, Hsc70 was differentially expressed by dihydrotestosterone (DHT) treatment in SV40-transformed DP cells.

CONCLUSION

These results suggest that Hsc70 may be involved in androgen action on DP cells.

Molecular insights into the hair follicle and its pathology: a review of recent developments

In the last few years by means of the elucidation of the human genome and the acquisition of powerful investigative tools we have begun to understand the molecular basis of hair follicle growth control. In this article I will describe some of the salient recent contributions to the field and review the implications these findings have had on our understanding of mechanisms in dermatology and dermatopathology.

Matriptase/MT-SP1 is required for postnatal survival, epidermal barrier function, hair follicle development, and thymic homeostasis

Matriptase/MT-SP1 is a novel tumor-associated type II transmembrane serine protease that is highly expressed in the epidermis, thymic stroma, and other epithelia. A null mutation was introduced into the Matriptase/MT-SP1 gene of mice to determine the role of Matriptase/MT-SP1 in epidermal development and neoplasia. Matriptase/MT-SP1-deficient mice developed to term but uniformly died within 48 h of birth. All epidermal surfaces of newborn mice were grossly abnormal with a dry, red, shiny, and wrinkled appearance. Matriptase/MT-SP1-deficiency caused striking malformations of the stratum corneum, characterized by dysmorphic and pleomorphic corneocytes and the absence of vesicular bodies in transitional layer cells. This aberrant skin development seriously compromised both inward and outward epidermal barrier function, leading to the rapid and fatal dehydration of Matriptase/MT-SP1-deficient pups. Loss of Matriptase/MT-SP1 also seriously affected hair follicle development resulting in generalized follicular hypoplasia, absence of erupted vibrissae, lack of vibrissal hair canal formation, ingrown vibrissae, and wholesale abortion of vibrissal follicles. Furthermore, Matriptase/MT-SP1-deficiency resulted in dramatically increased thymocyte apoptosis, and depletion of thymocytes. This study demonstrates that Matriptase/MT-SP1 has pleiotropic functions in the development of the epidermis, hair follicles, and cellular immune system.

The lysosomal protease cathepsin L is an important regulator of keratinocyte and melanocyte differentiation during hair follicle morphogenesis and cycling

We have previously shown that the ubiquitously expressed lysosomal cysteine protease, cathepsin L (CTSL), is essential for skin and hair follicle homeostasis. Here we examine the effect of CTSL deficiency on hair follicle development and cycling in ctsl(-/-) mice by light and electron microscopy, Ki67/terminal dUTP nick-end labeling, and trichohyalin immunofluorescence. Hair follicle morphogenesis in ctsl(-/-) mice was associated with several abnormalities. Defective terminal differentiation of keratinocytes occurred during the formation of the hair canal, resulting in disruption of hair shaft outgrowth. Both proliferation and apoptosis levels in keratinocytes and melanocytes were higher in ctsl(-/-) than in ctsl(+/+) hair follicles. The development of the hair follicle pigmentary unit was disrupted by vacuolation of differentiating melanocytes. Hair cycling was also abnormal in ctsl(-/-) mice. Final stages of hair follicle morphogenesis and the induction of hair follicle cycling were retarded. Thereafter, these follicles exhibited a truncated resting phase (telogen) and a premature entry into the first growth phase. Further abnormalities of telogen development included the defective anchoring of club hairs in the skin, which resulted in their abnormal shedding. Melanocyte vacuolation was again apparent during the hair cycle-associated reconstruction of the hair pigmentary unit. A hallmark of these ctsl(-/-) mice was the severe disruption in the exiting of hair shafts to the skin surface. This was mostly because of a failure of the inner root sheath (keratinocyte layer next to the hair shaft) to fully desquamate. These changes resulted in a massive dilation of the hair canal and the abnormal routing of sebaceous gland products to the skin surface. In summary, this study suggests novel roles for cathepsin proteases in skin, hair, and pigment biology. Principal target tissues that may contain protein substrate(s) for this cysteine protease include the developing hair cone, inner root sheath, anchoring apparatus of the telogen club, and organelles of lysosomal origin (eg, melanosomes).