Distribution of two basement membrane proteoglycans through hair follicle development and the hair growth cycle in the rat

Dermal papilla cell-secreted biglycan regulates hair follicle phase transit and regeneration by activating Wnt/β-catenin

Alopecia is a prevalent problem of cutaneous appendages and lacks effective therapy. Recently, researchers have been focusing on mesenchymal components of the hair follicle, i.e. dermal papilla cells, and we previously identified biglycan secreted by dermal papilla cells as the key factor responsible for hair follicle-inducing ability. In this research, we hypothesized biglycan played an important role in hair follicle cycle and regeneration through regulating the Wnt signalling pathway. To characterize the hair follicle cycle and the expression pattern of biglycan, we observed hair follicle morphology in C57BL/6 mice on Days 0, 3, 5, 12 and 18 post-depilation and found that biglycan is highly expressed at both mRNA and protein levels throughout anagen in HFs. To explore the role of biglycan during the phase transit process and regeneration, local injections were administered in C57BL/6 and nude mice. Results showed that local injection of biglycan in anagen HFs delayed catagen progression and involve activating the Wnt/β-catenin signalling pathway. Furthermore, local injection of biglycan induced HF regeneration and up-regulated expression of key Wnt factors in nude mice. In addition, cell analyses exhibited biglycan knockdown inactivated the Wnt signalling pathway in early-passage dermal papilla cell, whereas biglycan overexpression or incubation activated the Wnt signalling pathway in late-passage dermal papilla cells. These results indicate that biglycan plays a critical role in regulating HF cycle transit and regeneration in a paracrine and autocrine fashion by activating the Wnt/β-catenin signalling pathway and could be a potential treatment target for hair loss diseases.

Histological characteristics of hair follicles at different hair cycle and in vitro modeling of hair follicle-associated cells of yak (Bos grunniens)

To adapt to the extreme conditions of plateau environments, yaks have evolved thick hair, making them an ideal model for investigating the mechanisms involved in hair growth. We can gain valuable insights into how hair follicles develop and their cyclic growth in challenging environments by studying yaks. However, the lack of essential data on yak hair follicle histology and the absence of in vitro cell models for hair follicles serve as a limitation to such research objectives. In this study, we investigated the structure of skin tissue during different hair follicle cycles using the yak model. Additionally, we successfully established in vitro models of hair follicle-associated cells derived from yak skin, including dermal papilla cells (DPCs), preadipocytes, and fibroblasts. We optimized the microdissection technique for DPCs culture by simplifying the procedure and reducing the time required. Furthermore, we improved the methodology used to differentiate yak preadipocytes into mature adipocytes, thus increasing the differentiation efficiency. The introduction of yak as a natural model provides valuable research resources for exploring the mechanisms of hair growth and contributes to a deeper understanding of hair follicle biology and the development of regenerative medicine strategies.

Hair Histology and Glycosaminoglycans Distribution Probed by Infrared Spectral Imaging: Focus on Heparan Sulfate Proteoglycan and Glypican-1 during Hair Growth Cycle

The expression of glypicans in different hair follicle (HF) compartments and their potential roles during hair shaft growth are still poorly understood. Heparan sulfate proteoglycan (HSPG) distribution in HFs is classically investigated by conventional histology, biochemical analysis, and immunohistochemistry. In this report, a novel approach is proposed to assess hair histology and HSPG distribution changes in HFs at different phases of the hair growth cycle using infrared spectral imaging (IRSI). The distribution of HSPGs in HFs was probed by IRSI using the absorption region relevant to sulfation as a spectral marker. The findings were supported by Western immunoblotting and immunohistochemistry assays focusing on the glypican-1 expression and distribution in HFs. This study demonstrates the capacity of IRSI to identify the different HF tissue structures and to highlight protein, proteoglycan (PG), glycosaminoglycan (GAG), and sulfated GAG distribution in these structures. The comparison between anagen, catagen, and telogen phases shows the qualitative and/or quantitative evolution of GAGs as supported by Western immunoblotting. Thus, IRSI can simultaneously reveal the location of proteins, PGs, GAGs, and sulfated GAGs in HFs in a reagent- and label-free manner. From a dermatological point of view, IRSI shows its potential as a promising technique to study alopecia.

Screening of integrins localized on the surface of human epidermal melanocytes

In vivo, melanocytes occupy three-dimensional (3D) space. Nevertheless, most experiments involving melanocytes are performed in a two-dimensional microenvironment, resulting in difficulty obtaining accurate results. Therefore, it is necessary to construct an artificial in vivo-like 3D microenvironment. Here, as a step towards engineering a precisely defined acellular 3D microenvironment supporting the maintenance of human epidermal melanocytes (HEMs), we examined the types of integrin heterodimers that are expressed transcriptionally, translationally, and functionally in HEMs. Real-time PCR and fluorescent immunoassay analyses were used to elucidate the expression of integrin α and β subunit genes at the transcriptional and translational levels, respectively. The functionality of the presumed integrin heterodimers was confirmed using attachment and antibody-inhibition assays. Among the genes encoding 12 integrin subunits (α₁, α₂, α₃, α₄, α₅, α₆, α₇, α_V, β₁, β₃, β₅, and β₈) showing significantly higher transcription levels, proteins translated from the integrin α₂, α₄, α₅, β₁, β₃, and β₅ subunit genes were detected on the surface of HEMs. These HEMs showed significantly increased adhesion to collagen I, fibronectin, laminin, and vitronectin, and functional blockade of the integrin α₂ subunits significantly inhibited adhesion to collagen I, fibronectin, and laminin. In addition, there was no significant inhibition of the adhesion to fibronectin or vitronectin in HEMs with functional blockade of the integrin α₄, α₅, or α_V subunits. These results indicate that the active integrin α₂β₁ heterodimer and the inactive integrin α₄, α₅, α_V, β₃, and β₅ subunits are all localized on the surface of HEMs.

Immunoexpression of adhesion molecules during human fetal hair development

INTRODUCTION

Hair follicles are produced in a cyclical manner and the machinery involved in the reproduction of these follicles is present since the fetal stage. Although extensive research has been done on the human hair follicle, very little is known about the importance of adhesion molecules in its development.

MATERIAL AND METHODS

We analyzed here, the immunoexpression of beta-1 integrin, p-cadherin, e-cadherin, and beta-catenin in hair follicles from 26 formalin-fixed and paraffin-embedded skin samples from human embryos and fetus between 12-23 weeks of gestational age.

RESULTS

The adhesion molecules beta-1 integrin and e-cadherin/p-cadherin were expressed from 12 weeks and seemed to play a role in regulating epidermis invagination. Beta-catenin immunostaining was negative in all cases; down regulation of this protein may be necessary for fetal hair development and thus facilitating hair follicle down growth.

DISCUSSION/CONCLUSION

Adhesion molecules are essential for hair follicle down growth and proliferation; integrins and cadherins play a major role in this process. More studies are needed to describe hair follicle development.

Immunostaining study of cytokeratins in human hair follicle development

Background

The hair follicle is a unique structure, one of the most dynamic structures in mammalians, which can reproduce in every new cycle all the mechanism involved in its fetal development. Although a lot of research has been made about the human hair follicle much less has been discovered about the importance of the cytokeratins (CKs) in its development.

Objective

Study the immunohistochemical pattern of epithelial CKs during human hair follicle development.

Methods

We performed an immunohistochemical study using fresh post-mortem skin biopsies of human fetuses between 4 and 25 weeks of gestational age to study the expression of cytokeratins (CKs): CK1, CK10, CK13, CK14, CK16 and CK20 during human hair follicle fetal development.

Study limitations

Restrospective study with a good number of makers but with a small population.

Results/conclusion

We found that, the CKs were expressed in an intermediate time during follicular development. The epithelial CKs (CK1, CK14, CK10, CK13) and the epithelial CKs with a proliferative character such as CK16 were expressed first, as markers of cellular maturation and follicular keratinization. At a later phase, CK20 was expressed in more developed primitive hair follicles as previously discussed in literature.

The role of neprilysin in regulating the hair cycle

In most mammals, each hair follicle undergoes a cyclic process of growing, regressing and resting phases (anagen, catagen, telogen, respectively) called the hair cycle. Various biological factors have been reported to regulate or to synchronize with the hair cycle. Some factors involved in the extracellular matrix, which is a major component of skin tissue, are also thought to regulate the hair cycle. We have focused on an enzyme that degrades elastin, which is associated with skin elasticity. Since our previous study identified skin fibroblast elastase as neprilysin (NEP), we examined the fluctuation of NEP enzyme activity and its expression during the synchronized hair cycle of rats. NEP activity in the skin was elevated at early anagen, and decreased during catagen to telogen. The expression of NEP mRNA and protein levels was modulated similarly. Immunostaining showed changes in NEP localization throughout the hair cycle, from the follicular epithelium during early anagen to the dermal papilla during catagen. To determine whether NEP plays an important role in regulating the hair cycle, we used a specific inhibitor of NEP (NPLT). NPLT was applied topically daily to the dorsal skin of C3H mice, which had been depilated in advance. Mice treated with NPLT had significantly suppressed hair growth. These data suggest that NEP plays an important role in regulating the hair cycle by its increased expression and activity in the follicular epithelium during early anagen.

Evidence for Functional Importance of Usherin/Fibronectin Interactions in Retinal Basement Membranes

Usher syndrome is a genetically heterogeneous disorder characterized by hearing loss with retinitis pigmentosa. Usher syndrome type IIa is the most common of the Usher syndromes, accounting for over half of all cases. The gene encodes a 180 kDa basement membrane glycoprotein called usherin. Here, we demonstrated a specific interaction between usherin and fibronectin in retinal basement membranes. This interaction was confirmed using biochemical, biophysical, and genetic approaches. Surface plasmon resonance assay confirmed that fibronectin binding to usherin is of high affinity and 1:1 stoichiometry. Using a fusion peptide-based co-immunoprecipitation approach, we show that binding to fibronectin occurs at the LE domain of usherin. Recombinant LE domain-specific peptides were engineered that contained single amino acid substitutions corresponding to missense mutations found in humans with Usher syndrome type IIa. Only mutations in loop d of the LE domain abolished the ability of the LE domain to co-immunoprecipitate fibronectin.

Enzyme digestion to isolate and culture human scalp dermal papilla cells: a more efficient method

In this study, we show a more efficient method for isolation and cultivation of dermal papilla cells from hair follicles of human scalp skin. The dermal partments of low hair follicles were pulled out from cutaneous fat and the bulb epithelium was teased out from the fibrous sheath with attached dermal papilla by applying gentle pressure with the tip of an occal forceps. When these fibrous sheaths were entirely digested into isolated cells by collagenase D but the dermal papillae were justly to be digested, collagenase D was discarded and the dermal papillae were isolated completely out from the resuspension solution by repeated low-speed centrifugation and transferred to another dish for free-floating culture. This procedure markedly simplifies the steps of isolated dermal papilla operation and relieves the laborious tension. Furthermore, dermal papillae could be isolated on a large-scale and remained intact. After collagenase digestion, the dermal papillae showed very high adherent rate and quicker growth than that of microdissection, which suggests that the definition factor of dermal papilla cell migration was relaxed and some structure had been activated or exposed. The cells exhibited a multi-layer forming property and spread-out growth style. They showed positive with alcian blue, with toluidine blue O for different gradient pH and PAS, which was similar to the staining results of in situ dermal papilla. It suggests that the culture papilla cells still synthesize and excrete neutral and acid mucopolysaccharides. Our results demonstrate that the papilla cells in culture condition still remain the ability to synthesize the specific extracellular matrix components of in situ dermal papilla, which supports the concept that the dermal papilla cell, a highly specialized fibroblast, especially is involved in hair growth regulation.

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.

Chemical coupling of a monoclonal antisurfactant protein-B antibody to human urokinase for targeting surfactant-incorporating alveolar fibrin

Intraalveolar fibrin formation is a common histopathological finding in acute inflammatory and chronic interstitial lung diseases. Incorporation of hydrophobic surfactant components into polymerizing fibrin results in a severe loss of surface activity, altered mechanical and structural clot properties, and a reduced susceptibility toward fibrinolytic degradation. Such events have been implicated in atelectasis formation, impairment of gas exchange, and provocation of fibroproliferative changes. In an effort to address the unique features of alveolar fibrin, we designed a hybrid molecule consisting of a monoclonal antibody against surfactant protein SP-B (8B5E) and the catalytic domain of urokinase (B-chain), which was termed MABUC. The urokinase B-chain was prepared by limited reduction of human two-chain-urokinase and subsequent affinity purification and coupled to the antibody using a heterobifunctional cross-linker. Purification of the chimeric protein included gel filtration chromatography and affinity chromatography. An ELISA-like microtiter plate assay, based on the immunological detection of the SP-B moiety and the fibrinolytic activity of the u-PA domain, was developed for the detection of the hybrid molecule. Chromogenic substrate assays, (125)I-based fibrin plate assays, and active site titration were performed to analyze the specific fibrinolytic activity of the conjugate. MABUC was found to fully retain the ability of SP-B binding and the fibrinolytic activity of u-PA. In addition, MABUC was noted to be 1.5-2-fold more effective in the dissolution of surfactant embedding clots and to be approximately 3-fold more resistant against PAI-1, the predominant fibrinolysis inhibitor in the alveolar compartment, as compared to the native u-PA. The superiority of MABUC was particularly prominent (>5-fold efficacy) when investigating clot material incorporating both PAI-1 and surfactant, as a mimicry of alveolar fibrin. We conclude that urokinase and 8B5E can be cross-linked chemically, thus yielding a fibrinolytic enzyme with enhanced substrate specifity for surfactant-containing clots and higher PAI-1 resistance as compared to native u-PA.

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.

Basement membrane chondroitin sulfate proteoglycan and vascularization of the developing mammalian limb bud

We used immunocytochemistry to study the basement membrane-chondroitin sulfate proteoglycan (BM-CSPG) distribution in mammalian limb bud and its relationship to and possible role in limb development. Anti-BM-CSPG immunostaining was examined in the developing limb buds of 24 Sprague-Dawley rats at embryonic days 12 to 14 and 19. BM-CSPG immunostaining was present in 3 regions. The first region was located peripherally in the limb bud ectodermal basement membrane (BM) that separates ectoderm from mesoderm and was present at all embryonic stages examined. The second region was in the mesenchymal extracellular matrix independent of the vascular system. This staining pattern was diffuse, granular, and often homogeneous, except for clustering adjacent to developing vessels, and was observed distally in the limb bud. In the mesenchymal extracellular matrix adjacent to the distal BM this staining pattern formed fibrils that were perpendicular and connected to the limb bud BM and extended into the underlying mesenchyme. The third region was localized to the BM of developing blood vessels of the limb bud. Blood vessel staining allowed analysis of limb bud vessel formation. The early developing blood vessels at the proximal limb bud were organized differently from those located distally. Large central vessels were present proximally, whereas a rich plexus of smaller vascular channels was present at the distal margin. A subectodermal avascular zone was observed at the margin of the limb bud, except beneath the apical ectodermal ridge where immunostained blood vessels extended from the distal vascular plexus toward the apical ectodermal ridge. The formation of central larger vessels occurs proximally, whereas formation of peripheral smaller vessels seems to take place locally and distally under the influence of the apical ectodermal ridge. BM-CSPG plays an important role in blood vessel formation and mammalian limb bud development. (J Hand Surg 2000; 25A:150-158.

Selective activation of the versican promoter by epithelial- mesenchymal interactions during hair follicle development

Interaction between the epithelium and the mesenchyme is an essential feature of organogenesis, including hair follicle formation. The dermal papilla (DP), a dense aggregate of specialized dermis-derived stromal cells located at the bottom of the follicle, is a major component of hair that signals the follicular epithelial cells to prolong the hair growth process. However, little is known about DP-specific gene activation with regard to hair induction. In this study we demonstrate that a short fragment (839 bp) of the human versican (a core protein of one of the matrix chondroitin sulfate proteoglycans) promoter is sufficient to activate lacZ reporter gene expression in the DP of postnatal transgenic mice and also in the condensed mesenchyme (the origin of the DP) beneath the hair placode during hair follicle embryogenesis. Using the same versican promoter with green fluorescent protein (GFP), large numbers of fresh pelage DP cells were isolated from newborn transgenic skin by high-speed cell sorting. These GFP-positive DP cells showed abundant versican mRNA, confirming that the reporter molecules reflected endogenous versican gene expression. These sorted GFP-positive cells showed DP-like morphology in culture, but both GFP and versican expression was lost during primary culture. In vivo hair growth assays showed that GFP-positive cells could induce hair when grafted with epithelial cells, whereas GFP-negative cells grafted with epithelium or GFP-positive cells alone did not. These results suggest that versican may play an essential role both in mesenchymal condensation and in hair induction.

Morphogenesis of the glomerular filter: the synchronous assembly and maturation of two distinct extracellular matrices

The morphogenesis of the glomerular filtration apparatus during pre- and postnatal development in the rodent involves the coordinated assembly of two closely apposed but morphologically different extracellular matrices, the glomerular capillary basement membrane and the mesangial matrix. The cellular origin of these matrices is known to be distinct and complex; however, the mechanisms by which these matrices are assembled during morphogenesis are not entirely understood. It has been shown that in the earliest stages of glomerular morphogenesis the nascent glomerular basement membrane exists as a four-layered structure, the product of both the visceral epithelium and capillary endothelium. During the latter stages of glomerular development, the quadrilaminar structure becomes a trilaminar basement membrane, the event thought to occur by fusion of closely apposed basement membrane layers. In subsequent stages of maturation and throughout the life of the animal, the visceral epithelial cells, which line the periphery of the glomerular capillary, are the primary source of newly synthesized basement membrane material. The mesangial matrix, which lacks the specific organization of a basement membrane, first occurs in the developing glomerulus as a diffuse matrix central to the developing glomerular capillaries. During glomerular maturation the mesangial matrix undergoes a compaction/arborization coincident with the ramification of the vascular histoarchitecture of the glomerular tuft. Recent advances in the cell biology of basement membrane now demonstrate that there is a divergence in isoforms of the molecules that comprise the glomerular capillary basement membrane and mesangial matrices during development, possibly coincidental with functional specialization during the process of glomerular maturation.

cDNA cloning of the basement membrane chondroitin sulfate proteoglycan core protein, bamacan: a five domain structure including coiled-coil motifs

Basement membranes contain several proteoglycans, and those bearing heparan sulfate glycosaminoglycans such as perlecan and agrin usually predominate. Most mammalian basement membranes also contain chondroitin sulfate, and a core protein, bamacan, has been partially characterized. We have now obtained cDNA clones encoding the entire bamacan core protein of Mr = 138 kD, which reveal a five domain, head-rod-tail configuration. The head and tail are potentially globular, while the central large rod probably forms coiled-coil structures, with one large central and several very short interruptions. This molecular architecture is novel for an extracellular matrix molecule, but it resembles that of a group of intracellular proteins, including some proposed to stabilize the mitotic chromosome scaffold. We have previously proposed a similar stabilizing role for bamacan in the basement membrane matrix. The protein sequence has low overall homology, apart from very small NH2- and COOH-terminal motifs. At the junctions between the distal globular domains and the coiled-coil regions lie glycosylation sites, with up to three N-linked oligosaccharides and probably three chondroitin chains. Three other Ser-Gly dipeptides are unfavorable for substitution. Fusion protein antibodies stained basement membranes in a pattern commensurate with bamacan, and they also Western blotted bamacan core protein from rat L2 cell cultures. The antibodies could also specifically immunoprecipitate an in vitro transcription/translation product from a full-length bamacan cDNA. The unusual structure of this proteoglycan is indicative of specific functional roles in basement membrane physiology, commensurate with its distinct expression in development and changes in disease models.

Histochemistry of the human hair follicle

Immunohistochemistry of the human hair follicle is of increasing interest in hair research. The data on antigen distribution in the different epithelial and mesenchymal structures of this unique skin appendage are superfluous now. In the present chapter, I will concentrate on selected aspects related to hair follicle differentiation, epithelial-mesenchymal interactions, proliferation and metabolic activity. Hair diseases are common. Not unusually, hair growth and structure reflect systemic disturbances. Basic knowledge of hair anatomy and histochemistry is required for their rational evaluation. Immunohistochemistry is a valuable tool for microanatomy of the hair apparatus. It offers a link between the biochemical data and structural components of hair follicles, which may help to better understand physiology of hair growth and hair diseases.

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.

Hair follicle growth controls

Research in hair biology has embarked in the pursuit for molecules that control hair growth. Many molecules already have been associated with the controls of hair patterning, hair maturation, and hair cycling and differentiation. Knowing how these molecules work gives us the tools for understanding and treating patients with hair disorders.

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.

Regulated expression of chondroitin sulfates at sites of epithelial-mesenchymal interaction: spatio-temporal patterning identified with anti-chondroitin sulfate monoclonal antibodies

Chondroitin sulfate proteoglycans, cell surface and extracellular matrix molecules in both neural and non-neural tissues, are highly regulated during normal development. Entire proteoglycan molecules may be either up-regulated or down-regulated, or only the chondroitin sulfate glycosaminoglycan portions of these molecules may be modified. Subtle changes in the chemistries of chondroitin sulfate chains can now be identified through the use of a panel of anti-chondroitin sulfate monoclonal antibodies. Each of these antibodies recognizes specific chemical structures which are non-randomly dispersed along the lengths of chondroitin sulfate chains. The location of individual epitopes within defined domains in these chains is demonstrated through controlled treatments of aggrecan with chondroitinase ABC, whereby portions of these chains are removed from the non-reducing terminal ends and where the remainder of the chains remains covalently attached to the core protein. In these situations, some epitopes, such as those recognized by antibodies CS-56 and 6C3, can be removed without loss of other epitopes, such as that recognized by antibody 4C3. The independent expression of individual epitopes is demonstrated by immunocytochemical analyses of developing skin appendages in embryonic chicks and fetal humans. These are sites where highly patterned morphogenetic movements result from epithelial-mesenchymal interactions. In both chicks and humans, some epitopes are constitutively expressed while others are strictly regulated in the mesenchymal portions of the developing skin appendages. These data strongly suggest that chondroitin sulfate proteoglycans, including their chondroitin sulfate chains, have important roles in regulating these epithelial mesenchymal interactions. Furthermore, these data underscore the significance of the aforementioned observation that individual epitopes are located in specific domains within chondroitin sulfate chains. The highly organized expression of chondroitin sulfate proteoglycans in the development of the central nervous system strongly argues for a similar role for these molecules in the organs that comprise this system.

Basement membrane proteoglycans are of epithelial origin in rodent skin

Basement membrane proteoglycans in mammalian skin comprise at least one chondroitin sulfate proteoglycan and heparan sulfate proteoglycans, including perlecan. In this study, the origins of basement membrane chondroitin sulfate proteoglycan and perlecan were investigated both in vivo and in vitro. For in vivo experiments, pieces of newborn rat epidermis obtained by dispase treatment were grafted onto athymic nude mice. Three and six weeks after grafting, immunofluorescence analysis of the grafted skin was carried out, using monoclonal antibodies specific for rat basement membrane chondroitin sulfate proteoglycan and rat and mouse perlecan. While the isolated rat epidermis was shown to completely lack rat basement membrane chondroitin sulfate proteoglycan and rat basement membrane heparan sulfate proteoglycans, including perlecan, immunofluorescence staining of tissue sections from the grafted sites on mice demonstrated the presence of rat basement membrane chondroitin sulfate proteoglycan and rat perlecan on interfollicular and follicular basement membranes including that separating dermal papillae from adjacent hair follicle epithelium. In contrast, the basement membranes of all dermal capillaries were positive for mouse perlecan, but negative for rat basement membrane chondroitin sulfate proteoglycan and rat perlecan, including the basement membranes of papillary dermal capillaries beneath the rat epidermis. These data suggest that basement membrane proteoglycans of the dermal-epidermal junction and hair follicle epithelium are of epidermal (epithelial) origin in vivo. Stratified rat keratinocytes cultured on a collagen matrix at the air-liquid interface showed the synthesis of perlecan, laminin 1, and type IV collagen in basement membranes, but not clearly detectable basement membrane chondroitin sulfate proteoglycan.

Influence of testosterone on chondroitin sulphate proteoglycan in the rat prostate

There are recognized interactions between prostatic stromal and epithelial cells. These interactions may be influenced by the composition of the extracellular matrix, which is composed of proteins such as collagen, laminin, fibronectin, and proteoglycans (PGs) such as chondroitin sulphate proteoglycan (CSPG). In our continuing studies on prostate biology, we examined the three lobes of the normal adult rat prostate, i.e., ventral, dorsal, and lateral, for CSPG by indirect immunofluorescence, using an immunospecific monoclonal antibody (CS-56) for the chondroitin sulphate (CS) moiety of the PG. Staining of the prostate sections with CS-56 antibody followed by labelling with IgG fluorescein isothiocyanate conjugate indicated strong fluorescent signals associated with the ventral lobe basement membrane. The signal was stronger and more continuous in the distal acini than in the proximal acini. The staining of the dorsal and lateral lobes was less intense than that of the ventral lobe. Following castration of the rats, the basement membrane staining became discontinuous. Androgen replacement by administration of testosterone propionate (TP) reversed the effects of castration. Quantification of the total CS content showed decreases of about 60% in the ventral and lateral lobes after castration. TP administration for 14 days increased the total CS content several fold above the values for castrated rats in all lobes. The results demonstrated that CS content was significantly higher for TP-treated animals, suggesting that the expression of prostate CSPG is regulated by androgens. This approach should be useful in the study of the extracellular matrix in prostate biology.

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.

Utilization of transgenic mice in the study of matrix degrading proteinases and their inhibitors

The extracellular matrix (ECM) acts as both a structural scaffold and an informational medium. Its dynamic status is determined by cells that secrete its constituent molecules and, in most cases, also secrete enzymes that catalyze degradation of these molecules. A stasis between ECM degrading enzymes and their inhibitors maintains the integrity of the matrix. While controlled ECM remodelling is fundamental to several normal processes, uncontrolled disruption underlies diverse pathological conditions. Transgenic mice with specific modulations or a total lack of expression of certain metalloproteinases, serine proteinases or their inhibitors have been generated to elucidate endogenous expression patterns, identify regulatory elements of these genes, and study the physiological consequences of their deregulated expression. With these models we enhance our understanding of the role of proteinases and their inhibitors in diverse normal processes and pathologies including mammary gland development, hemostasis, emphysema and cancer.

Chondroitin sulfate proteoglycans in the developing cerebral cortex: the distribution of neurocan distinguishes forming afferent and efferent axonal pathways

The first thalamocortical axons to arrive in the developing cerebral cortex traverse a pathway that is separate from the adjacent intracortical pathway for early efferents, suggesting that different molecular signals guide their growth. We previously demonstrated that the intracortical pathway for thalamic axons is centered on the subplate (Bicknese et al. [1994] J. Neurosci. 14:3500-3510), which is rich in chondroitin sulfate proteoglycans (CSPGs; Sheppard et al. [1991] J. Neurosci. 11:3928-3942), whereas efferent axons cross the subplate to exit in a zone containing much less CSPG. To define the molecular composition of the subplate further, we used antibodies against CSPG core proteins and chondroitin sulfate disaccharides in an immunohistochemical analysis of their distribution in the developing neocortex of the rat. Immunolabeling for neurocan, a central nervous system-specific CSPG (Rauch et al. [1992] J. Biol. Chem. 267:19537-19547), and for chondroitin 6-sulfate and unsulfated chondroitin becomes prominent in the subplate before the arrival of thalamic afferents. Immunolabeling is initially sparse in the cortical plate but appears later in maturing cortical layers. A postnatal decline in immunolabeling occurs uniformly for most proteoglycans, but, in the somatosensory cortex, labeling for neurocan, phosphacan, and chondroitin 4- and 6-sulfate declines in the centers of the whisker barrels before the walls. In contrast to neurocan, immunolabeling for other proteoglycans is either uniformly distributed (syndecan-1, N-syndecan, 5F3, phosphacan, chondroitin 4-sulfate), restricted to axons (PGM1), distributed exclusively on nonneuronal elements (2D6, NG2, and CD44), or undetectable (9.2.27, aggrecan, decorin). Thus, neurocan is a candidate molecule for delineating the intracortical pathway of thalamocortical axons and distinguishing it from that of cortical efferents.

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.

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.

Hyaluronan is inversely correlated with the expression of CD44 in the dermal condensation of the embryonic hair follicle

Previously, we have shown that CD44 (the hyaluronan receptor) was involved in the degradation of hyaluronan. In the present study, we examined the distribution of CD44 and hyaluronan in the skin of embryonic and mature mice. During embryonic development, CD44 was prominently expressed by the condensed mesenchymal cells involved in the formation of the hair follicles, but was absent from the surrounding interstitial cells. The cells of the dermal condensation expressed CD44 throughout the development of the hair follicle; however, once the hair follicle reached maturity, the mesenchymal cells of the dermal papilla no longer expressed this molecule. In contrast to the above, the distribution of hyaluronan was reversed from that of CD44. Hyaluronan was widespread throughout the embryonic dermis, but was conspicuously absent from the regions of the dermal condensation. This arrangement persisted through the development of the hair follicle; however, in the mature hair follicle, hyaluronan reappeared in the dermal papilla. Thus, in the embryonic dermis, the expression of CD44 and hyaluronan were complementary to each other. However, in the adult skin, only minor changes were detected in the levels of CD44 and hyaluronan associated with the cells of the dermal condensation during the hair cycle. When organ cultures of embryonic mouse skin were treated with Streptomyces hyaluronidase, the interstitial mesenchymal cells became compacted, indicating that the removal of hyaluronan leads to the condensation of these cells. The results of this study are consistent with the hypothesis that the expression of CD44 by the inductive mesenchymal cells allows them to degrade hyaluronan in a localized region, leading to formation and maintenance of the dermal condensation.

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.

Fibroblast growth factor and epidermal growth factor in hair development

Hair follicles arise in developing skin as a result of a complex of interactions that are likely to be mediated by diffusible, cell- and matrix-bound factors. Growth factors such as fibroblast growth factor (FGF) and epidermal growth factor (EGF) have been implicated in the control of epidermal and mesenchymal cell function, and it is likely that they also affect proliferation and differentiation of the cells of the cutaneous appendages during development. Immunolocalization of basic FGF adjacent to areas of proliferation in developing and in mature follicles suggests that this factor may regulate the mitotic activity of epithelially-derived cells; acidic FGF, on the other hand, appears in the differentiating cells of the follicle bulb and may therefore participate in the formation of structural components of the follicle or of the fiber. EGF has been identified as a potent modulator of cellular growth and is also present during follicle differentiation. These factors may act through autocrine and paracrine mechanisms because their receptors are also found on epidermally derived and mesenchymal structures in the skin. We have studied the effects of these growth factors on hair follicle development in the newborn mouse. Daily injections for 1 week after birth resulted in significant changes in the morphogenesis of the hair follicle population. Histologic examination of skin of FGF-treated mice suggested that the growth factor had affected hair follicle initiation and development, which resulted in a significant delay in the first and subsequent hair cycles when compared to control animals. Because aFGF and bFGF are not readily diffusible, these effects remained confined to the area of treatment. In contrast, EGF affected the whole body coat of the treated animals, induced hyperkeratinization of the skin, and caused a significant delay in hair follicle development.

Basement membrane proteoglycans and development

Basement membranes contain distinct collagen, glycoprotein and proteoglycan species, and these exhibit considerable heterogeneity in isoform or type when different tissue types are compared. Additionally, many components are differentially expressed in organogenesis. We have considered the distributions in glomerulogenesis of two distinct basement membrane proteoglycans, a small heparan sulfate proteoglycan and a chondroitin sulfate proteoglycan (BM-CSPG). While the former was present in all kidney basement membranes through development, the latter was apparently regulated in distribution. BM-CSPG was only strongly expressed in the vasculature invading late comma stage glomeruli, and later in presumptive and mature Bowman's capsule. Over the first six to eight weeks, the capillary basement membranes contained BM-CSPG, but in gradually decreasing amounts until it became completely undetectable. The basement membrane of the adult rat glomerulus is unique in its lack of BM-CSPG. However, in diabetic rats, BM-CSPG is apparently re-expressed in the glomerular basement membrane, a potential marker for pathological changes in glomerular structure. While its function awaits elucidation, BM-CSPG may be essential for basement membrane integrity or stability and have important roles in kidney development.

Mechanism of androgen action in cultured dermal papilla cells derived from human hair follicles with varying responses to androgens in vivo

Androgens are major regulators of human hair growth, but their effects vary: many follicles are stimulated by androgens, e.g., beard; some remain unaffected, e.g., eyelashes; whereas scalp follicles undergo regression and balding in genetically disposed individuals. Because the dermal papilla controls many aspects of the hair follicle, androgens may act via the dermal papilla, affecting the other follicular components indirectly. In this hypothesis androgens would alter dermal papilla cell production of regulatory substances, e.g., growth factors and/or extracellular matrix components. To test this theory the mechanism of androgen action has been compared in primary lines of dermal papilla cells cultured from androgen-dependent follicles and relatively androgen-independent non-balding scalp. Androgen receptor levels were assayed by saturation analysis (9-10 points; 0.05-10 nmol/l) using the synthetic androgen [3H]-mibolerone and specificity was confirmed by competition studies. Androgen metabolism was investigated both intracellularly and in the media after a 2-h incubation with 5 nM [3H]-testosterone. Carrier and [14C] steroids were added to the extracts before separation by thin-layer chromatography; steroid identity was confirmed by recrystallization. Dermal papilla cells from androgen-dependent follicles contained higher levels of specific, high-affinity, low-capacity androgen receptors than non-balding scalp cells. Testosterone metabolism also varied with beard, public and scalp cells containing testosterone and androstenedione intracellularly, but only beard cells producing 5 alpha-dihydrotestosterone, in line with the scanty beard growth found in 5 alpha-reductase deficiency. Elsewhere we have shown that cultured dermal papilla cells produce extracellular matrix components and mitogenic factors. These results all concur with our original hypothesis and suggest that further studies of such cells may elucidate the paradoxical effects of androgens on human hair follicles.

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.

Scarring alopecia in discoid lupus erythematosus

The clinicopathological features of the scarring alopecia of discoid lupus erythematosus (DLE) were studied. Scarring alopecia was present in 34% of 89 patients with DLE and was associated with a prolonged disease course. More than half these patients had scalp involvement at the onset of the disease. There was a significant reduction in size of sebaceous glands in affected scalp. Perifollicular lymphocytic inflammation was maximal around the mid-follicle at the level of the sebaceous gland, which seems to be an important functional level in the follicle. There are changes in the expression of the matrix molecules, the proteoglycans, in the connective tissue sheath and the keratin intermediate filaments in the outer root sheath cells at this level in normal scalp and in diseased scalp. Loss of a population of mid-follicular stem cells may be important in the pathogenesis of scarring alopecia in DLE.

Morphea with high titer of fibronectin antibodies

A 20-year-old man with a 9-year history of unusual subcutaneous morphea with nodular lesions in a circular arrangement and wooden-hard symmetrical induration of the arms, had high titers of fibronectin antibodies. A possible role of fibronectin and antifibronectin antibodies in the pathogenesis of scleroderma is discussed.