Distribution of proteoglycans during the hair growth cycle in human skin

V3: an enigmatic isoform of the proteoglycan versican

V3 is an isoform of the extracellular matrix (ECM) proteoglycan (PG) versican generated through alternative splicing of the versican gene such that the two major exons coding for sequences in the protein core that support chondroitin sulfate (CS) glycosaminoglycan (GAG) chain attachment are excluded. Thus, versican V3 isoform carries no GAGs. A survey of PubMed reveals only 50 publications specifically on V3 versican, so it is a very understudied member of the versican family, partly because to date there are no antibodies that can distinguish V3 from the CS-carrying isoforms of versican, that is, to facilitate functional and mechanistic studies. However, a number of in vitro and in vivo studies have identified the expression of the V3 transcript during different phases of development and in disease, and selective overexpression of V3 has shown dramatic phenotypic effects in "gain and loss of function" studies in experimental models. Thus, we thought it would be useful and instructive to discuss the discovery, characterization, and the putative biological importance of the enigmatic V3 isoform of versican.

Effect of Marine-Derived Saccharides on Human Skin Fibroblasts and Dermal Papilla Cells

The skin is the largest organ of the human body, composed of a diverse range of cell types, non-cellular components, and an extracellular matrix. With aging, molecules that are part of the extracellular matrix undergo qualitative and quantitative changes and the effects, such as a loss of skin firmness or wrinkles, can be visible. The changes caused by the aging process do not only affect the surface of the skin, but also extend to skin appendages such as hair follicles. In the present study, the ability of marine-derived saccharides, L-fucose and chondroitin sulphate disaccharide, to support skin and hair health and minimize the effects of intrinsic and extrinsic aging was investigated. The potential of the tested samples to prevent adverse changes in the skin and hair through stimulation of natural processes, cellular proliferation, and production of extracellular matrix components collagen, elastin, or glycosaminoglycans was investigated. The tested compounds, L-fucose and chondroitin sulphate disaccharide, supported skin and hair health, especially in terms of anti-aging effects. The obtained results indicate that both ingredients support and promote the proliferation of dermal fibroblasts and dermal papilla cells, provide cells with a supply of sulphated disaccharide GAG building blocks, increase ECM molecule production (collagen and elastin) by HDFa, and support the growth phase of the hair cycle (anagen).

Gellan gum-based hydrogels support the recreation of the dermal papilla microenvironment

The dermal papilla (DP), a specialized compartment within the hair follicle, regulates hair growth. However, human DP cells rapidly lose their inductivity in 2D-culture given the loss of positional and microenvironmental cues. Spheroids have been capable of recreating the 3D intercellular organization of DP cells, however, DP cell-matrix interactions are poorly represented. Considering the specific nature of the DP's extracellular matrix (ECM), we functionalized gellan gum (GG) with collagen IV-(HepIII) or fibronectin-(cRGDfC) derived peptide sequences to generate a 3D environment in which the phenotype and physiological functions of DP cells are restored. We further tuned the stiffness of the microenvironments by varying GG amount. Biomimetic peptides in stiffer hydrogels promoted the adhesion of DP cells, while each peptide and amount of polymer independently influenced the type and quantity of ECM proteins deposited. Furthermore, although peptides did not seem to have an influence, stiffer hydrogels improved the inductive capacity of DP cells after short term culture. Interestingly, independently of the peptide, these hydrogels supported the recapitulation of basic hair morphogenesis-like events when incorporated in an organotypic human skin in vitro model. Our work demonstrates that tailored GG hydrogels support the generation of a microenvironment in which both cell-ECM and cell-cell interactions positively influence DP cells towards the creation of an artificial DP.

Regulation of stem cell fate by HSPGs: implication in hair follicle cycling

Heparan sulfate proteoglycans (HSPGs) are part of proteoglycan family. They are composed of heparan sulfate (HS)-type glycosaminoglycan (GAG) chains covalently linked to a core protein. By interacting with growth factors and/or receptors, they regulate numerous pathways including Wnt, hedgehog (Hh), bone morphogenic protein (BMP) and fibroblast growth factor (FGF) pathways. They act as inhibitor or activator of these pathways to modulate embryonic and adult stem cell fate during organ morphogenesis, regeneration and homeostasis. This review summarizes the knowledge on HSPG structure and classification and explores several signaling pathways regulated by HSPGs in stem cell fate. A specific focus on hair follicle stem cell fate and the possibility to target HSPGs in order to tackle hair loss are discussed in more dermatological and cosmeceutical perspectives.

Hair Growth-Promoting Activities of Glycosaminoglycans Extracted from the Tunics of Ascidian (Halocynthia roretzi)

Throughout the ages, hair has had psychological and sociological importance in framing the personality and general appearance of an individual. Despite efforts to solve this problem, no groundbreaking measures have been proposed. Glycosaminoglycans (GAGs) and associated proteoglycans have important functions in homeostatic maintenance and regenerative processes of the skin. However, little is known about the role of these molecules in the regulation of the hair follicle cycle. Three fractions (F1, F2 and F3) were obtained after separation and purification of GAGs from ascidian tunics. F1 was observed to contain a small amount of amino sugar while high contents of galactose and N-acetylglucosamine were noted in F2 and F3. 2-acetamido-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (∆Di-6S) and 2-acetamido-2-deoxy-3-O-(β-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (∆Di-4S) were the main disaccharide components. F3 exhibited the highest proliferation activity on human follicle dermal papilla (HFDP) cells. In addition, mixed samples (FFM) of F2 and F3 at different concentrations showed peak activities for five days. After cell culture at a concentration of 10 mg/mL and dihydrotestosterone (DHT), the inhibition effect was higher than that for Minoxidil. Application of 10 mg of FFM to the hair of mice for 28 days resulted in a hair growth effect similar to that of Minoxidil, a positive control.

Following historical "tracks" of hair follicle miniaturisation in patterned hair loss: Are elastin bodies the forgotten aetiology?

Pattern hair loss (PHL) is a chronic regressive condition of the scalp, where follicular miniaturisation and decreased scalp hair coverage occurs in affected areas. In all PHL cases, there is a measurable progressive shortening of the terminal hair growth duration, along with reduced linear growth rates. In both genders, PHL initially shows an increase in short telogen hairs ≤30 mm in length, reflecting a cycle completion of under 6 months in affected terminal hair follicles. To understand the miniaturisation process, we re-examine the dynamics of miniaturisation and ask the question, "why do miniaturised hair follicles resist treatment?" In the light of recent developments in relation to hair regeneration, we looked back in the older literature for helpful clues "lost to time" and reprise a 1978 Hermann Pinkus observation of an array of elastin deposits beneath the dermal papilla following subsequent anagen/telogen transitions in male balding, originally described by Arao and Perkins who concluded that these changes provide a "morphologic marker of the entire biologic process in the balding scalp." Thus, we have reviewed the role of the elastin-like bodies in hair pathology and we propose that alterations in elastin architecture may contribute to the failure of vellus-like hair reverting back to their terminal status and may indicate a new area for therapeutic intervention.

Heparan Sulfate Proteoglycans: Key Mediators of Stem Cell Function

Heparan sulfate proteoglycans (HSPGs) are an evolutionarily ancient subclass of glycoproteins with exquisite structural complexity. They are ubiquitously expressed across tissues and have been found to exert a multitude of effects on cell behavior and the surrounding microenvironment. Evidence has shown that heterogeneity in HSPG composition is crucial to its functions as an essential scaffolding component in the extracellular matrix as well as a vital cell surface signaling co-receptor. Here, we provide an overview of the significance of HSPGs as essential regulators of stem cell function. We discuss the various roles of HSPGs in distinct stem cell types during key physiological events, from development through to tissue homeostasis and regeneration. The contribution of aberrant HSPG production to altered stem cell properties and dysregulated cellular homeostasis characteristic of cancer is also reviewed. Finally, we consider approaches to better understand and exploit the multifaceted functions of HSPGs in influencing stem cell characteristics for cell therapy and associated culture expansion strategies.

The microfollicle: a model of the human hair follicle for in vitro studies

Access to complex in vitro models that recapitulate the unique markers and cell-cell interactions of the hair follicle is rather limited. Creation of scalable, affordable, and relevant in vitro systems which can provide predictive screens of cosmetic ingredients and therapeutic actives for hair health would be highly valued. In this study, we explore the features of the microfollicle, a human hair follicle organoid model based on the spatio-temporally defined co-culture of primary cells. The microfollicle provides a 3D differentiation platform for outer root sheath keratinocytes, dermal papilla fibroblasts, and melanocytes, via epidermal-mesenchymal-neuroectodermal cross-talk. For assay applications, microfollicle cultures were adapted to 96-well plates suitable for medium-throughput testing up to 21 days, and characterized for their spatial and lineage markers. The microfollicles showed hair-specific keratin expression in both early and late stages of cultivation. The gene expression profile of microfollicles was also compared with human clinical biopsy samples in response to the benchmark hair-growth compound, minoxidil. The gene expression changes in microfollicles showed up to 75% overlap with the corresponding gene expression signature observed in the clinical study. Based on our results, the cultivation of the microfollicle appears to be a practical tool for generating testable insights for hair follicle development and offers a complex model for pre-clinical substance testing.

Integral Roles of Specific Proteoglycans in Hair Growth and Hair Loss: Mechanisms behind the Bioactivity of Proteoglycan Replacement Therapy with Nourkrin® with Marilex® in Pattern Hair Loss and Telogen Effluvium

Follicular proteoglycans are key players with structural, functional, and regulatory roles in the growth and cycling behaviour of the hair follicles. The expression pattern of specific proteoglycans is strongly correlated with follicular phase transitions, which further affirms their functional involvement. Research shows that bioactive proteoglycans, e.g., versican and decorin, can actively trigger follicular phase shift by their anagen-inducing, anagen-maintaining, and immunoregulatory properties. This emerging insight has led to the recognition of “dysregulated proteoglycan metabolism” as a plausible causal or mediating pathology in hair growth disorders in both men and women. In support of this, declined expression of proteoglycans has been reported in cases of anagen shortening and follicular miniaturisation. To facilitate scientific communication, we propose designating this pathology “follicular hypoglycania (FHG),” which results from an impaired ability of follicular cells to replenish and maintain a minimum relative concentration of key proteoglycans during anagen. Lasting FHG may advance to structural decay, called proteoglycan follicular atrophy (PFA). This process is suggested to be an integral pathogenetic factor in pattern hair loss (PHL) and telogen effluvium (TE). To address FHG and PFA, a proteoglycan replacement therapy (PRT) program using oral administration of a marine-derived extract (Nourkrin® with Marilex®, produced by Pharma Medico Aps, Aarhus, Denmark) containing specific proteoglycans has been developed. In clinical studies, this treatment significantly reduced hair fall, promoted hair growth, and improved quality of life in patients with male- and female-pattern hair loss. Accordingly, PRT (using Nourkrin® with Marilex®) can be recommended as an add-on treatment or monotherapy in patients with PHL and TE.

Isolating Dermal Papilla Cells from Human Hair Follicles Using Microdissection and Enzyme Digestion

The dermal papilla (DP) is a cluster of mesenchymal cells located at the bottom of the hair follicle. Cells within the DP interact with numerous other cell types within the follicle, including epithelial stem cells, matrix cells, and melanocytes, regulating their function. The diameter of the DP is directly proportional to the width of the hair shaft, and a decrease in both cell number and DP size is observed in hair loss conditions such as androgenetic alopecia. Conversely, microdissected ex vivo DP can instruct growth of de novo hair follicles. The study of DP cells and their role in human hair growth is often hampered by the technical challenge of DP isolation and culture. Here we describe a method used within our research group for isolating DP from human hair follicles.

Optimal stimulation toward the dermal papilla lineage can be promoted by combined use of osteogenic and adipogenic inducers

Dermal papilla cells (DPCs) play crucial roles in hair regeneration, but they readily lose their hair‐forming ability during in vitro culture. Although the formation of spheroids partially restores the ability, shrinkage of the spheroids makes it difficult to maintain cellular viability. To address this problem, we stimulated DPCs with factors known to induce adipogenic and/or osteogenic differentiation, because DPCs share unique gene expression profiles with adipocytes and osteocytes. We isolated DPCs from versican (vcan)–GFP mice, in which GFP is expressed under the control of a vcan promoter, which is strongly active in DPCs of anagen hair follicles. GFP fluorescence was most intense when the spheroids were made from DPCs cultured in a half‐diluted combination of adipogenic and osteogenic media (CAO1/2), a Dulbecco’s modified Eagle’s medium‐based medium that contains 10% FBS, 275 nm dexamethasone, 2.5 mm β‐glycerol phosphate, 12.5 µg·mL⁻¹ ascorbic acid, 0.125 µm isobutylmethylxanthine and 2.5 ng·mL⁻¹ insulin. The dose of each additive used was less than the optimal dose for adipogenic or osteogenic differentiation, and shrinkage of the spheroids was avoided through the addition of fibroblast growth factor 2 and platelet‐derived growth factor‐AA to  CAO1/2. In addition, the gene and protein expression of vcan, osteopontin, alkaline phosphatase and α‐smooth muscle actin in the spheroids were augmented to levels similar to those of the intact dermal papillae, which exhibited restored hair‐forming activity. In conclusion, a combination of certain adipogenic and osteogenic inducers, together with fibroblast growth factor 2 and platelet‐derived growth factor‐AA, can promote differentiation toward the DPC lineage.

Methods for the isolation and 3D culture of dermal papilla cells from human hair follicles

The dermal papilla is a cluster of mesenchymal cells located at the base of the hair follicle which have a number of important roles in the regulation of hair growth. As a consequence, in vitro models of these cells are widely used to study the molecular mechanisms which underlie hair follicle induction, growth and maintenance. While dermal papilla from rodent hair follicles can be digested prior to cell isolation, the unique extracellular matrix composition found in human dermal papilla renders enzymes such as trypsin and collagenase insufficient for digestion of the dermal papilla into a single cell suspension. As such, to grow human dermal papilla cells in vitro, the papilla has to first be isolated via a micro-dissection approach from the follicle. In this article we describe the micro-dissection and culture methods, which we use within our laboratory, for the study of human dermal papilla cells.

Isolation and Quantification of Glycosaminoglycans from Human Hair Shaft

Background

There is evidence that glycosaminoglycans (GAGs) are present in the hair shaft within the follicle but there are no studies regarding GAGs isolation and measurement in the human hair shaft over the scalp surface, it means, in the free hair shaft.

Objective

The purpose of our research was to isolate and measure the total GAGs from human free hair shaft.

Methods

Seventy-five healthy individuals participated in the study, 58 adults, men and women over the age of 50 and 17 children (aged 4~9). GAGs in hair samples, received from the parietal and the occipital areas, were isolated with 4 M guanidine HCl and measured by the uronic acid-carbazole reaction assay.

Results

GAGs concentration was significantly higher in the occipital area than in the parietal area, in all study groups. GAG levels from both areas were significantly higher in children than in adults. GAG levels were not associated with gender, hair color or type.

Conclusion

We report the presence of GAGs in the human free hair shaft and the correlation of hair GAG levels with the scalp area and participants' age.

Pregnancy and the hair growth cycle: anagen induction against hair growth disruption using Nourkrin® with Marilex® , a proteoglycan replacement therapy

Postpartum effluvium is a well-known clinical fact. However, following some minor research activities in the 1960s, very little has happened on the research front of the subject. It was hypothesized that postpartum hair loss might be a manifestation of a change in the hair growth cycle occurring normally during pregnancy. Recently, new research has been published trying to explain the mechanism of action behind this frequently occurring hair growth disruption, and to develop a functional treatment schedule and regime. Under normal circumstances, postpartum effluvium will disappear by itself as a function of time, and therefore adequate information to the patient is important in order to reduce the anxiety that it will not be a permanent problem. However, in some subjects it can manifest itself for longer stages and even become permanent. At the present time, treatments aim at correcting underlying hormonal imbalances and at improving overall cosmetic appearance. Several treatments in the form of thyroid supplementation, topical progesterone and estradiol lotions, and even oral contraceptive have been studied. All the available studies have significant limitations in their scientific basis, such as small sample size, absence of control group, or highly subjective measurement of treatment response. It is evident from the available studies that no specific treatment has been investigated thoroughly enough to justify recommendation in clinical treatment or to be termed "effective." Without the ability to provide a pathogenic diagnosis or causality criteria, chances are low that a treatment by trial and error will adequately be able to control hair effluvium. Current hair treatment strategies are symptomatic and nonspecific; therefore, future research must aim at developing new and targeted methods with a point of departure in observing concomitant biological mechanisms. Based on the research in the 1960s, current knowledge about the hair follicle and the regulation of the hair cycles, we believe that an anagen inducer in the form of a specific proteoglycan replacement therapy (Nourkrin^® with Marilex^® from Pharma Medico) could be a proper solution to shorten the hair eclipse phenomenon - and give the patient a feeling of control and empowerment.

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.

Thyroid hormone action on skin

The skin characteristics associated with thyroid hormone are classic. The name "myxedema" refers to the associated skin condition caused by increased glycosaminoglycan deposition in the skin. Generalized myxedema is still the classic cutaneous sign of hypothyroidism. It is caused by deposition of dermal acid mucopolysaccharides, notably hyaluronic acid. Despite its appearance, the skin does not pit with pressure.

Proteoglycan expression patterns in human hair follicle

BACKGROUND

Proteoglycans (PGs) are known to play key roles in many cellular signalling pathways involved in hair follicle biology. Although some PG core proteins have previously been described in adult human hair follicles, their glycosaminoglycan (GAG) moieties have been less studied.

OBJECTIVES

To add knowledge about PG core protein and GAG distributions in human anagen hair follicle and, for selected follicles, during catagen.

METHODS

We used immunohistochemistry and immunohistofluorescence to revisit the expression pattern of GAG chains and core proteins in human hair follicle. The studied epitopes included CD44v3, syndecan-1, perlecan, versican, aggrecan, biglycan, heparan sulphate (HS), chondroitin sulphate (CS), dermatan sulphate (DS) and keratan sulphate (KS).

RESULTS

The membrane PGs syndecan-1 and CD44v3 were respectively detected in the epithelial part of whole hair and in the outer root sheath basal layer. The dermal part of the hair follicle contained high amounts of extracellular PGs such as perlecan, versican, aggrecan, biglycan and their saccharidic moieties, namely HS, CS, DS and KS. We also observed a variable distribution of these components along the hair follicle. Especially, we noted a PG impoverishment at the very bottom of the anagen bulb. Moreover, while type D chondroitin expression remained unaffected, 4C3-CS and PG4-CS/DS epitopes respectively decreased in the dermal papilla and the connective tissue sheath, at the onset of catagen.

CONCLUSIONS

GAG and PG expression along the human anagen hair follicle was characterized by (i) discontinuities mainly affecting the basement membrane and (ii) disappearance of some epitopes at catagen onset. These results are discussed in term of functionalities in nutrient diffusion, cell proliferation and differentiation, and hair protection.

Hair cycle-specific expression of versican in human hair follicles

BACKGROUND

Versican, a large chondroitin sulfate proteoglycan molecule, is implicated in the induction of hair morphogenesis, the initiation of hair regeneration, and the maintenance of hair growth in mouse species. In contrast, in human hair follicles, the distribution and the roles of versican remains obscure.

OBJECTIVES

To elucidate the implication of versican in normal human hair growth.

METHODS

Versican expression was examined by in situ hybridization (mRNA) and immunohistochemistry (protein).

RESULTS

The results clearly showed specific versican gene expression in the dermal papilla of anagen, which apparently decreased in the dermal papilla of catagen hair follicles. No specific signal was detectable in telogen hair follicles. Consistent with ISH results, versican immunoreactivity was extended over the dermal papilla of anagen hair follicles, and again, this staining diminished in the catagen phase of human hair follicles. Interestingly, versican proteins were deposited outside K15-positive epithelial cells in the bulge throughout the hair cycle. Versican immunoreactivity in the dermal papilla was almost lost in vellus-like hair follicles affected by male pattern baldness.

CONCLUSION

Specific expression of versican in the anagen hair follicles suggests its importance to maintain the normal growing phase of human as well as mouse.

Comparison between the expression of basement membrane zone antigens of human interfollicular epidermis and anagen hair follicle using indirect immunofluorescence

BACKGROUND

The composition of the basement membrane zone (BMZ) or dermal-epidermal junction in the interfollicular skin has been well documented. However, little is known about the BMZ or connective tissue-epithelial junction along the hair follicle.

OBJECTIVES

To determine whether the BMZ antigens in the interfollicular epidermis are also present in the BMZ of the anagen hair follicle and to compare whether the expression and distribution of the BMZ components vary between the interfollicular epidermis and the anagen follicle and within different regions of the hair follicle.

METHODS

Longitudinal cryostat sections of scalp margin specimens from four adult patients undergoing cosmetic surgery, and without known pathology were stained with a panel of monoclonal and polyclonal antibodies to different BMZ constituents using standard indirect immunofluorescence.

RESULTS

All the BMZ antigens found in the normal interfollicular epidermis were expressed in the anagen follicle; however, there were regional variations in the intensity and patterns of fluorescence. All the antigens were expressed in a continuous linear pattern along the BMZ of the interfollicular skin, the infundibulum, and the middle part of the hair follicle. Differences were observed in the lower follicle and the hair bulb. There was continuous expression throughout the BMZ of the follicle of laminin-1 and collagen IV, but in contrast, expression of other antigens decreased down the lower follicle. There was weak or even negative staining with antibodies to alpha 6 beta 4 integrin, laminin-5, anchoring filaments, and type VII collagen in the outer aspect of the bulb compared with the hair papilla. In addition, there were special patterns observed along the bilateral middle and lower follicle.

CONCLUSIONS

Despite the common embryological origin between the interfollicular epidermis and the hair follicle, there is variation in the expression of the BMZ antigens. This may be explained by the histological specialization and functional requirements that reflect the dynamic hair growth cycle.

Plasticity and cytokinetic dynamics of the hair follicle mesenchyme during the hair growth cycle: implications for growth control and hair follicle transformations

Hair fiber production is the macroscopic end-point of a highly complex set of interactions between the hair follicle's epithelial and mesenchymal components. The nature of this relationship is largely set during hair follicle morphogenesis, but is dramatically revisited in the adult during the unique tissue remodeling events required for hair follicle cycling. Whereas significant attention has focused on the fate of the hair follicle epithelium during these events, associated changes in hair follicle fibroblast subpopulations remain unclear. Here, we present a speculative review that represents a critical and innovative synthesis of the current literature and summarizes a recently submitted original study by the authors, on the nature of hair cycle-dependent fibroblast dynamics and on how perturbations thereof may lead to several clinical manifestations of altered human hair growth.

Plasticity and cytokinetic dynamics of the hair follicle mesenchyme: implications for hair growth control

The continuously remodeled hair follicle is a uniquely exploitable epithelial-mesenchymal interaction system. In contrast to the cyclical fate of the hair follicle epithelium, the dynamics of the supposedly stable hair follicle mesenchyme remains enigmatic. Here we address this issue using the C57BL/6 hair research model. During hair growth, increase in total follicular papilla size was associated with doubling of papilla cell numbers, much of which occurred before intra-follicular papilla cell proliferation, and subsequent to mitosis in the proximal connective tissue sheath. This indicates that some papilla cells originate in, and migrate from, the proliferating pool of connective tissue sheath fibroblasts. Follicular papilla cell number and total papilla size were maximal by anagen VI, but intriguingly, decreased by 25% during this period of sustained hair production. This cell loss, which continued during catagen, was not associated with intra-follicular papilla apoptosis, strongly indicating that fibroblasts migrate out of the late anagen/early catagen papilla and re-enter the proximal connective tissue sheath. Low-level apoptosis occurred only here, along with the "detachment" of cells from the regressing connective tissue sheath. Thus, the hair follicle mesenchyme exhibits significant hair cycle-associated plasticity. Modulation of these cell interchanges is likely to be important during clinically important hair follicle transformations, e.g. vellus-to-terminal and terminal-to-vellus during androgenetic alopecia.

Molecular control of epithelial-mesenchymal interactions during hair follicle cycling

Epithelial-mesenchymal interactions play pivotal roles in the morphogenesis of many organs and various types of appendages. During hair follicle development, extensive interactions between two embryologically different hair follicle compartments (epidermal keratinocytes and dermal papilla fibroblasts) lead to the formation of the hair shaft-producing mini-organ that shows cyclic activity during postnatal life with periods of active growth, involution and resting. During the hair cycle, the epithelium and the mesenchyme are regulated by a distinct set of molecular signals that are unique for every distinct phase of the hair cycle. In telogen hair follicles, epithelial-mesenchymal interactions are characterized by a predominance of inhibitory signals that retain the hair follicle in a quiescent state. During anagen, a large variety of growth stimulatory pathways are activated in the epithelium and in the mesenchyme, the coordination of which are essential for proper hair fiber formation. During catagen, the termination of anagen-specific signaling interactions between the epithelium and the mesenchyme leads to apoptosis in the hair follicle epithelium, while activation of selected signaling pathways promotes the transition of the dermal papilla into a quiescent state. The signaling exchange between the follicular epithelium and the mesenchyme is modulated by proteoglycans, such as versican, which may significantly enhance or reduce the biological activities of secreted growth stimulators. However, additional research will be required to bridge the gap between our current understanding of mechanisms underlying epithelial-mesenchymal interactions in hair follicles and the potential clinical application of growth modulators involved in those interactions. Further progress in this area of research will hopefully lead to the development of new drugs for the treatment of hair growth disorders.

Purification and characterization of the endoglycosidase heparanase 1 from human plantar stratum corneum: a key enzyme in epidermal physiology?

A protein exhibiting endoglycosidase activity was purified from plantar stratum corneum to apparent homogeneity in two sequential column chromatographic steps. Protein sequencing revealed its identity with the recently cloned human heparanase 1, an enzyme, the expression of which is reported to be related to the metastasic potential of tumor cells. By using a heparanase 1 specific antibody we were able to demonstrate that, in the plantar stratum corneum, heparanase 1 exists in two forms, the active 50 kDa protein and the inactive 63 kDa form, probably a proform of the enzyme. The antibody also decorated numerous degradation fragments. Reverse transcription polymerase chain reaction studies as well as immunohistochemical analysis using reconstructed and normal human epidermis demonstrated clearly a keratinocyte differentiation related expression of heparanase 1. Interestingly, the antibody also strongly decorated dendritic cells, which after double labeling could be identified to be a subpopulation of the epidermal Langerhans cells. Based on our findings and the known history of this enzyme, we advanced the hypothesis that heparanase 1 has multiple physiologic functions in the epidermis: (i) it plays an important role in epidermal differentiation, possibly by modulating the liberation of heparan sulfate bound (growth) factors; (ii) in the stratum corneum, the endoglycosidase activity of heparanase 1 might be indispensable and represent the first step in the desquamation process; and (iii) in Langerhans cells, its catalytic activity is required for the trans-tissue migration of these cells.

Controls of hair follicle cycling

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

Isolation and separation of proteoglycans

Proteoglycans contain a polypeptide core and an oligosaccharide chain composed of aminohexoses and uronic acid. The glycan chain is attached to the polypeptide in a bond to serine hydroxyl. The glycan chains may contain up to 200 disaccharide units and the proteoglycan molecular mass ranges from a few thousands to millions. Their physiological functions are related to barriers limiting diffusion across the membranes, articular lubrification, blood coagulation and cellular adhesion. The tissue proteoglycans can be extracted with 4 M guanidine hydrochloride and purified with chromatographic techniques. The soluble proteoglycans can be precipitated with cetylpyridinium chloride, purified by chromatography or by dialysis. All proteoglycan species are amenable to electrophoresis on polyacrylamide gels, and after blotting on polyvinylidene fluoride membranes, they can be stained for glycans. Proteoglycan analyses have shown their value in clinical mucopolysaccharidosis diagnostics, in occupational toxicology and in coagulation studies. Experimental applications include cell adhesion studies in tumor biology, regeneration in neurosciences or maturation of skin and kidneys.

Induction of apoptosis through the PKC pathway in cultured dermal papilla fibroblasts

The dermal papilla (DP) consists of a discrete population of specialized fibroblasts that are important in the morphogenesis of the hair follicle in the embryo and in the control of the hair growth cycle in the adult. This mitotically quiescent and long-lived cell population expresses gene products that promote cell survival such as Bcl-2, and thus normally might be protected from apoptosis. We investigated whether cultured DP fibroblasts are able to undergo apoptosis by treatment with the protein kinase inhibitor staurosporine. Involvement of the PKC signaling pathway in DP fibroblast survival/death was investigated by inhibition (staurosporine and Bisindolylmaleimide (Bis) treatment) or activation (TPA; 12-O-tetradecanoylphorbol-13-acetate treatment) of PKC and characterization of DP-expressed PKC isoforms by RT-PCR. We determined that cultured DP fibroblasts undergo apoptosis, in a dose-related manner, when treated with staurosporine but not when treated with Bis, an inhibitor with narrow PKC isoform specificity. TPA confers partial and transient resistance to staurosporine-induced DP apoptosis. Staurosporine and Bis each induced G1 arrest, whereas TPA treatment of cultured DP resulted in increased entry into S-phase. The differential responses to individual inhibitors and activators of PKC may be related to the multiple PKC isoforms that DP fibroblasts express. Flow cytometric analysis indicates that the mechanism of staurosporine-induced apoptosis may be through decrease of Bcl-2 in treated DP cells or through modulation of cell cycle regulators. Correlation between sensitivity to induction of apoptosis and proliferation suggests that dermal papilla cells may normally be protected from apoptosis in vivo by their mitotically quiescent state.

Genetic control of cytokines. Cytokine gene polymorphisms in alopecia areata

It is likely that alopecia areata is a multifactorial disease determined by a combination of genetic and environmental factors. The interaction of susceptibility genes with environmental factors gives rise to the disease phenotype, and then genetic modifying factors determine the extent of the inflammatory response and thereby the clinical outcome. Cytokines regulate the inflammatory response. Polymorphisms in these genes may therefore determine the amount of a cytokine that is produced in response to an environmental trigger such as a bacterial or viral infection.

Inhibitory effects of bFGF, VEGF and minoxidil on collagen synthesis by cultured hair dermal papilla cells

Dermal papilla cells of rat vibrissa follicles cultivated in monolayers and in three-dimensional collagen gels show a different morphology in these culture systems. Dermal papilla cells cultured in lattices tend to express morphological features resembling those seen in vivo. Quantification of total collagen by incorporation of 3H-proline in monolayer cultures and in collagen lattices show that the amount of collagen found in dermal papilla cells is higher than that secreted. Moreover, collagen synthesis measured in lattices is reduced to about 50% of that found in monolayer cultures. The influence of growth factors on collagen synthesis by hair dermal papilla cells was investigated. We studied the effects of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and minoxidil on collagen synthesis in monolayers and in lattices. VEGF, bFGF and minoxidil significantly decreased the total amount of collagen. In monolayer cultures, there was approximately a 30% inhibition of collagen production with 5 ng/ml bFGF, 0.1 ng/ml VEGF and 100 ng/ml minoxidil. However, in the lattices this inhibition was reduced to about half. These results suggest that both culture substrate and growth factors influence collagen production by rat hair dermal papilla cells.

Association of versican with dermal matrices and its potential role in hair follicle development and cycling

Versican is a member of the group of aggregating proteoglycans involved in matrix assembly and structure and in cell adhesion. We examined changes in the distribution of versican in mammalian skin, with emphasis on hair follicle development and cycling. In adult human skin, immunostaining for versican appeared predominantly in the dermis, with intense staining of the reticular dermis. Weak staining was observed at the dermoepidermal junction and the connective tissue sheath of hair follicles. Versican expression was also noted in the reticular dermis of rat skin, within dermal papillae, and possibly associated with follicle basement membranes. During mouse hair follicle development, versican was not expressed until the hair follicles were beginning to produce fibers. With follicle maturation, versican expression intensified in the dermal papillae, reaching a maximum at the height of the growth phase (anagen), after which it diminished as the end of this phase approached. Versican immunoreactivity in the papillae decreased further during catagen and was absent from these structures during telogen. However, intense staining for versican was then observed in the neck regions of telogen follicles. As the follicles entered the next hair cycle, versican disappeared from the necks and was again seen in the dermal papillae when follicles began producing fibers. This type of expression continued throughout subsequent hair cycles and is unlike any other dermal papilla component. The results of this study are consistent with a distinct supportive role for versican in the follicle matrices during hair follicle morphogenesis and cycling.

Extracellular matrix derived from hair and skin fibroblasts stimulates human skin melanocyte tyrosinase activity

There is indirect evidence that both skin and hair melanocytes are regulated by the activity of adjacent cells. In hair, the specialized fibroblasts (dermal papilla cells) appear to play a role in the regulation of hair growth. Hair pigmentation may relate to hair growth. In skin, melanocytes are located adjacent to the basement membrane zone. As far as we are aware, direct interactions of fibroblasts with melanocytes have not previously been investigated. Accordingly, the objective of this study was to develop co-culture conditions in which to investigate whether dermal fibroblasts from skin or hair could influence melanocyte differentiation. The influence of fibroblast-conditioned media, co-culture with fibroblasts, and fibroblast-derived extracellular matrix (ECM) on normal human skin melanocyte tyrosinase activity was examined. Fibroblasts from both skin and hair were capable of altering melanocyte morphology and significantly increasing tyrosinase activity when melanocytes were cultured in the absence, but not the presence, of the major proliferative drives. Although stimulation of tyrosinase activity was detectable with conditioned medium and co-culture with fibroblasts, the most striking result was obtained with the fibroblast-produced ECM which, on average, produced a four-fold increase in tyrosinase activity within 6 days. Thus, the study describes co-culture conditions in which the stimulatory effect of the fibroblast on melanocyte differentiation can be examined.

The basement membrane zone of the nail

The anatomy of the epidermis, dermis and subcutaneous tissues of the nail apparatus is distinct from that of non-appendageal skin. Apart from the demonstration of the longitudinal configuration of the dermal-epidermal junction of the nail bed, there have been no studies of the composition of the basement membrane zone of the nail apparatus. We obtained three human accessory digits, including one thumb, all of which had been amputated for cosmetic reasons, and were without known pathology. Specimens were stained with a battery of monoclonal and polyclonal antibodies which target normal basement membrane zone antigens, and studied by indirect immunofluorescence. This study demonstrated that the four distinct regions of the nail, namely the proximal nail fold, the nail matrix, the nail bed and the hyponychium expressed all the target antigens found in the normal non-appendageal basement membrane. In particular, there was normal expression of the epidermal-associated antigens, the 220- and 180-kDa bullous pemphigoid antigens, and the alpha 6 beta 4 integrin. There was also normal expression of the lamina lucida antigens LH39, GB3 and laminin. It is of interest that the dermal-associated components, namely the 285-kDa linear IgA antigen, the extracellular matrix glycoproteins chondroitin sulphate, type VII collagen and its closely associated proteins, and the poorly characterized antigen for LH24 and LH39 were all normally expressed. Fibronectin, which is not a normal basement membrane zone component, was diffusely expressed in the extracellular matrix, but did not accentuate the basement membrane zone.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative analysis of surface antigens in cultured human outer root sheath cells and epidermal keratinocytes: persistence of low expression of class I MHC antigens in outer root sheath cells in vitro

In the anagen human hair follicle, the epithelial cells from the infrainfundibular portion and the hair matrix cells express markedly lower numbers of major histocompatibility complex class I molecules than interfollicular epidermal keratinocytes. During the catagen phase of the hair cycle, class I expression on these cells increases, and activated macrophages aggregate around the follicle, which has led to the hypothesis that the cells to be resorbed are recognized by virtue of their low class I antigen expression. In the present study, we showed that, in vitro, outer root sheath cells also maintain a lower constitutive expression of MHC class I molecules compared with epidermal keratinocytes. In contrast, other surface antigens such as HLA-DR, -DP and -DQ, ICAM-1, LFA-3 and CD29, which are all known to participate in leucocyte-keratinocyte interactions, were similarly expressed in both cell types. Furthermore, interferon gamma strongly upregulated MHC class I and II and ICAM-1 expression in both cell types, whereas CD29 and LFA-3 remained unaffected. Tumour necrosis factor alpha, to a lesser extent, also upregulated MHC class I and ICAM-1 expression, but not class II expression. The differences in constitutive surface antigen expression of infrainfundibular outer root sheath cells compared with interfollicular epidermal keratinocytes emphasizes a distinct role of this cell type in the hair cycle, and possibly also in alopecia areata.

Molecules of the cycling hair follicle--a tabulated review

In this review we tabulated molecules which have been experimentally identified to be associated with, or play a role in, hair follicle growth. While compiling these data we were impressed by the fact that this field is only now beginning to be developed in terms of molecular analysis. Ironically, hair was used in some of the earliest molecular approaches to biologic structure (e.g. Astbury and Street, 1931), but the field did not develop from there. From our review we have come to the following conclusions. (1) As indicated by the growing number of reports dealing with follicle-associated molecules in the past 3 years, the field of hair biology has entered a new molecular era. (2) In many reported hair biology studies not enough emphasis has been placed on the fact that the follicle is a dynamic structure. All too often a study is limited to follicles of one particular phase of the cycle or one phase of development. Students in the field have to be more sensitive to the remarkable changes that this deceptively simple structure can undergo during its cycle. (3) Although we have not been able to find any molecules unique to the follicle, some of the structural molecules come close to an ideal tool. It is our impression that even more specific molecule tags will be found. Whether this requires a subtraction library approach or gene mapping of specific mutants is not yet clear. It would appear that the large, diverse family of intermediate filament-associated proteins will prove to be an excellent source of unique follicle-labeling molecules. (4) There is an acute need for molecules which distinguish the phases of the cycle, e.g. telogen from early anagen. Telogen is by far the most difficult phase to identify morphologically since the earliest phase of anagen and the latest phase of catagen may appear structurally like telogen. That these phases are functionally distinguishable must imply a molecular difference. As the number of recognized hair follicle-associated molecules and their interactions increase, it will be essential to assemble libraries of highly specific RNA and antibody probes for localization and mapping studies. We recognize that this review, as written, is imperfect. It is particularly deficient in making any effort towards identifying unifying principles of structure and function. We look forward to returning to this subject within 3 years.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlation of proteolytic activities of organ cultured intact mouse skin with defined hair cycle stages

The cyclic growth activity of the hair follicle is characterized by substantial remodelling of the extracellular matrix, yet, little is known about the proteolytic activities regulating this process. In murine skin, hair cycling is highly synchronized and is associated with dramatic remodeling of all skin compartments. We therefore have assessed, in this pilot study, proteolytic activities of murine skin from various stages of the depilation-induced hair cycle. We show that the defined proteolytic activities displayed by organ cultured intact mouse skin differ between hair cycle stages. Skin with all follicles in telogen or mid anagen displayed only minimal lysis of collagen type I gels, while early anagen skin had significant collagenase activity. Skin cultured on gelatin gels at the air-liquid interphase ('histoculture') completely lysed the gel within 5 days when all follicles were in early anagen, while this was not observed with mid and very late-anagen skin. Zymography of conditioned medium from these cultures revealed the secretion of activated interstitial collagenase and of gelatinases of 72 and 92 kDa, with the maximum of interstitial collagenase activity secreted by anagen IV skin. Addition of TPA or TNF-alpha to the culture medium stimulated secreted collagenase type I activity. The C 57 BL-6 mouse offers an attractive model for dissecting and manipulating hair cycle-associated proteolysis in a physiologically relevant system.

Dynamic expression patterns of tenascin, proteoglycans, and cell adhesion molecules during human hair follicle morphogenesis

The development of skin appendages such as hair, feathers, and teeth is brought about by reciprocal interactions between epidermal and mesenchymal tissues and is thought to be influenced in part by cell adhesion molecules and components of the extracellular matrix. The developmental distributions of tenascin, neural cell adhesion molecule (NCAM), E-cadherin, intercellular adhesion molecule 1 (ICAM-1), chondroitin sulfate proteoglycan (CSPG), and the heparan sulfate proteoglycan perlecan were studied in relation to hair follicle morphogenesis in fetal human skin. Tenascin first appeared in developing skin in focal concentrations at the epidermal-mesenchymal interface, just prior to, and presumably correlated with, hair follicle initiation. Tenascin immunostaining remained prominent in the basement membrane zone and extracellular matrix of the follicle sheath during subsequent morphogenetic stages. Two forms of tenascin (M(r) 250 x 10(3) and 280-300 x 10(3)), were revealed by Western blots of skin extracts. NCAM immunolabeling was initially present throughout the dermis, and became progressively restricted to the dermal condensation and the follicle sheath. Western blot analysis revealed an isoform of NCAM (M(r) 160 x 10(3)) which lacked polysialic acid. At all stages, E-cadherin staining was diminished on follicle cells situated adjacent to the basement membrane, relative to cells in the follicle interior. Follicle-specific immunostaining for ICAM-1 was transient, appearing only at the pre-germ and hair germ stages of development. Antibodies to three distinct CSPG determinants revealed unique immunolabeling patterns following follicle initiation: One CSPG epitope co-distributed with tenascin in the follicle basement membrane and follicle sheath extracellular matrix; one CSPG epitope was similarly expressed, and was also found on follicle epithelial cells; and the third CSPG determinant was noticeably absent from the follicle sheath during elongation of the developing appendage. Perlecan was concentrated in the dermal papilla, in addition to its distribution in all skin basement membranes. A model for how these diverse molecules may interact to influence human hair follicle morphogenesis is presented.

Hair follicle proteoglycans

Proteoglycans are polymorphic macromolecules present in all mammalian tissues, including the skin and its appendages. They consist of a core protein to which one or more glycosaminoglycan chains are covalently attached. Broadly, they can be divided into classes based on location and core protein structure. These classes include cell surface proteoglycans, basement membrane proteoglycans, small leucine-rich proteoglycans, large proteoglycans aggregating with hyaluronan, and intracellular granule proteoglycans. They have a wide range of functions, but little is known of the proteoglycans that are present in the epithelial and stromal compartments of hair follicles. However, the transmembrane proteoglycan syndecan may be important in follicle morphogenesis, both with respect to the epithelium and dermal papilla cells. Syndecan may possess both heparan and chondroitin sulfate chains, interacts with growth factors as well as fibronectin and interstitial collagens, and can associate in a transmembrane relationship with the cellular cytoskeleton. It is strongly expressed in mesenchymal cells coincident with stromal-epithelial interactions during tissue morphogenesis. Proteoglycans are present in all basement membranes, including those surrounding the epithelial compartment of hair follicles. Additionally, and quite unlike the dermis, the dermal papilla is enriched in basement-membrane components, especially a chondroitin 6-sulfate-containing proteoglycan, BM-CSPG. The function of this proteoglycan is not known, but developmental studies indicate that it may have a role in stabilizing basement membranes. In the hair cycle, BM-CSPG decreases through catagen and is virtually absent from the telogen papilla. One or more heparan sulfate proteoglycans, including perlecan, are also present in papilla and follicular basement membranes. Some of the leucine-rich proteoglycans, such as decorin, are associated with interstitial collagens, and may influence fibrillogenesis. Because small amounts of types I and III collagens may be present in anagen papillae, decorin may also be a constituent.

Morphological analysis of in vitro human hair growth

The histological and ultrastructural aspect of normal human hair follicles maintained ex vivo for 12 days was evaluated. Anagen hair follicles, dissected free of contaminating connective tissue, were maintained for up to 12 days in a serum-free medium. Macroscopic observations revealed continued viability for 12 days, at which time some follicles involuted in a manner morphologically similar to catagen. Increased growth of maintained follicles was measured from the abrupt ending of the connective tissue sheath (CTS), as no increase in this component was observed from initiation of culture. In general follicles maintained up to 8 days exhibited little divergence from normal in vivo morphologies including the persistence of functional hair bulb melanocytes--a marker of anagen. After this time melanin granules were present in dermal papilla cells, as occurs during impending involution in vivo. Heterotypic cell contact occurred in the middle to upper follicle between outer root sheath (ORS) keratinocytes and disorganized CTS. Herniation of some ORS cells away from the follicle and the occurrence of loose desmosomal junctions between ORS keratinocytes reflected loss of normal follicular cell interactions in upper follicles maintained after 8 days. Continued follicle growth correlated with the presence of mitotic matrix keratinocytes even at 12 days. After 12 days in culture most follicles involuted displaying apoptotic-like keratinocytes and hair bulb melanocytes and the presence of highly keratinized hair 'club' structures. While most follicles exhibited this orderly sequence of events, a few follicles involuted after 24 h with synchronous degeneration of all cells. Two follicles exhibited upregulated cortical cell differentiation at the level of the dermal papilla (DP).(ABSTRACT TRUNCATED AT 250 WORDS)

Rat hair follicle growth in vitro

Pelage hair follicles were isolated by gentle microdissection from 8-12-day-old rats, and maintained in supplemented Williams E medium. Length measurements made on freshly isolated hair follicles, and at 24-h intervals, showed a significant increase in hair follicle length over 48 h, after which time no further significant increase in length was observed. Photomicrographs of maintained follicles showed that this increase in hair follicle length could be attributed to the production of a keratinized hair shaft. Histology and [methyl-3H] thymidine autoradiography of freshly isolated hair follicles showed the dermal papilla to be elongated, with thymidine uptake located predominantly in the matrix cells of the hair follicle bulb adjacent to the dermal papilla. This pattern remained unaltered for the first 48 h of maintenance, but after 72 h the dermal papilla had rounded into a tight ball of cells, with very little thymidine uptake occurring in the adjacent matrix cells. On maintenance, fetal calf serum (FCS), epidermal growth factor (EGF) and 12-o-tetradecanoyl phorbol 13-acetate (TPA) all significantly stimulated [methyl-3H] thymidine and [U-14C] leucine uptake, but inhibited hair follicle elongation. Insulin-like growth factor-1 (IGF-1) had no significant effect on rates of hair follicle elongation and [methyl-3H] thymidine uptake, but significantly stimulated rates of [U-14C] leucine uptake. Transforming growth factor-beta 1 (TGF-beta 1) significantly inhibited both the rate of [methyl-3H] thymidine uptake and hair follicle elongation.

Glycosaminoglycan synthesis by cultured human hair follicle dermal papilla cells: comparison with non-follicular dermal fibroblasts

The extracellular matrix of the hair follicle dermal papilla is rich in glycosaminoglycans, the expression of which varies during the hair growth cycle being maximal in anagen and becoming undetectable as the follicle enters telogen. These observations, together with other experimental and clinical evidence, suggest that glycosaminoglycans may be involved in regulating hair growth. To investigate the metabolism of glycosaminoglycans by the dermal papilla we have measured the incorporation of radiolabelled precursors into glycosaminoglycans released into extracellular matrix and culture medium by cultured human dermal papilla cells. We also studied glycosaminoglycan synthesis by cells cultured from the lower follicular connective tissue sheath and by non-follicular dermal fibroblasts. Compared with dermal fibroblasts, dermal papilla cells showed a three to fourfold higher level of incorporation of 35S-sulphate and 3H-glucosamine into extracellular matrix glycosaminoglycans. Dermal papilla cells also released more 3H-glucosamine-labelled glycosaminoglycan into culture medium than dermal fibroblasts but there was no difference in 35S-sulphate labelling. These findings indicate that dermal papilla cells maintain a high level of glycosaminoglycan synthesis in vitro. Specific enzyme/chemical degradation showed that dermal papilla cells and dermal fibroblasts synthesized the same glycosaminoglycan types. However, the results suggested that dermal papilla glycosaminoglycans are less sulphated than those synthesized by dermal fibroblasts and that a higher proportion of sulphated glycosaminoglycans is retained in an extracellular matrix. The synthesis of glycosaminoglycans by connective tissue sheath cells was similar to that of dermal papilla cells, supporting the view that the dermal papilla and connective tissue sheath share certain properties.

Improved method for the isolation and cultivation of human scalp dermal papilla cells

We present an improved method for the isolation and cultivation of human scalp anagen hair follicle dermal papilla cells. Following treatment of the isolated dermal papilla with collagenase, incubation in Chang's medium mediates accelerated growth of the papilla cells when compared with other media such as DMEM, M199, and EMEM. Upon reaching confluency, the cells cultured in this fashion exhibit a multilayer-forming property that is dependent on normal proteoglycan synthesis. The papilla cells maintain this morphologic behavior for as long as 7 weeks in culture, or after being subcultured six times. During this time, the cells continue to synthesize extracellular matrix components associated with the human anagen follicle in situ. These include chondroitin sulfate, laminin, and type IV collagen. Type III collagen and keratan sulfate are poorly expressed by the papilla both in situ and in vitro. Heparan sulfate proteoglycan, a matrix component of the papilla in situ, is poorly expressed in vitro. Earlier reports suggested that the expression of extracellular matrix components is not maintained in culture. We show that the expression of these molecules is not dependent on the secondary culture medium, but continues in DMEM and M199 after primary culture in Chang's medium. Our results suggest that initial exposure of the dermal papilla to Chang's medium either selectively permits the outgrowth of papilla cells having extracellular matrix components similar to those found in situ, or stabilizes the expression of extracellular matrix components among the entire cultured cell population.