Co-culture of human hair follicles and dermal papillae in a collagen matrix

Human hair follicles, either alone or in combination with dermal papillae, were cultured in a collagen matrix. When plucked hair follicles were cultured alone, spike-like structures composed of outer root sheath cells started growing around the follicle and then radiated into the gel. When isolated dermal papillae were embedded close to the follicles, spikes started growing earlier and grew more rapidly than without the papillae. In cultures of excised follicles from which the dermal papilla had been removed, epithelial cells (possibly hair bulb cells) started growing out from the bulbous portion and then also formed spikes. In the presence of a papilla, the spikes elongated toward the papilla, finally reaching and surrounding it. These findings suggest that dermal papilla cells produce a factor(s) that enhances growth of follicular epithelial cells and also attracts those cells. In cultures of whole excised follicles, two major characteristic patterns of cellular growth were recognized. When the dermal papilla remained inside the bulb in contact with the hair bulb matrix, the hair matrix cells proliferated and differentiated in the normal manner, resulting in elongation of the hair shaft and follicle. But when the papilla was detached from the hair bulb matrix, epithelial cells proliferated from the bulbous portion and finally formed hair follicle-like structures. Thus, attachment of the dermal papilla to the hair bulb matrix in the bulbous portion appears to be necessary for growth of the hair and follicle in the normal manner. Our model may be useful for examining the interaction between follicular epithelial cells and dermal papillae and for studying the growth of hair and follicles in vitro.     

A procedure for the culture of hair follicles as functionally intact organoids

In fundamental studies of cellular differentiation and gene expression in relation to hair growth, there is a major need for a follicle culture system that would allow, for example, the transfection of hair cells with isolated keratin genes so that their tissue-specific expression can be investigated. Furthermore, such a culture system would be of enormous benefit for examining the effects of nutritional factors, hormones, and drugs known to alter hair growth as well as the biologic and molecular action of carcinogens in the development of epithelial neoplasms.

Recently, there have been several attempts to develop follicle cultures, but with only partial success.^1,2 In our study, we used a collagen matrix so that isolated hair follicles could be maintained as threedimensional structures for relatively prolonged periods of time, thereby allowing analysis of the different facets mentioned above. The most definitive feature for evaluating maintenance of hair growth is the continued synthesis of hair-specific proteins.     

Three-dimensional culture of plucked human hair follicles inside the collagen gel matrix

Plucked human hair follicles were cultured in collagen gel matrix. Epithelial cells, possibly outer root sheath keratinocytes, appeared from the outer root sheath 4 to 5 days after culturing and continually grew into the gel to form spike-like structures for next 3 weeks. The number and size of the spikes differed in each follicle. Autoradiographically, many DNA-synthesizing cells were seen at the outer cell layer in the enlarged outer root sheath and at the edges in the newly formed spike-like structures. The culture method described here appears to be suitable to study the three-dimensional growth, morphogenesis and differentiation of the outer root sheath cells in vitro.     

Apoptosis in murine hair follicles during catagen regression

Catagen hair follicle involution has been reported to involve apoptosis, although the precise mechanism has not been satisfactorily resolved. Previous studies have involved solely morphological or electron microscopical methods. We report here studies on murine hair follicles during the first postnatal hair cycle conducted using the terminal deoxy-nucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method. Electrophoresis of DNA isolated from the hair follicles of the same animals was carried out in order to confirm the systematic fragmentation of DNA that typifies apoptosis. On day 10, when all the follicles were growing, there was no evidence of staining with TUNEL in the hair bulbs. Electrophoresis similarly did not show characteristic DNA ladders. By day 15, a few positive cells were observed in the hair bulbs and the numbers had increased by day 17 when many positive cells were seen, especially in the lower portions of the follicles. Electrophoresis demonstrated DNA ladders on days 15, 16 and 17, although the DNA ladder on day 15 was less prominent than that on day 17. These studies confirmed that apoptosis, as identified by techniques that measure DNA fragmentation, occurs in the lower regions of hair follicles towards the end of catagen. Received: 19 March 1997     

Roxithromycin antagonizes catagen induction in murine and human hair follicles: implication of topical roxithromycin as hair restoration reagent

Roxithromycin (RXM) is a 14-member macrolide antibiotics, with a variety of bioregulatory functions including anti-apoptotic activity to keratinocytes. Therefore, RXM has been used for many kinds of skin diseases. In this study, human and murine hair follicles were treated with RXM in order to find the possibility to cure hair loss disease such as androgenetic alopecia (AGA). In AGA, dihydrotestosterone signals apoptosis in dermal papilla cells in susceptible individuals, resting in premature termination of anagen and early entry into catagen. Therefore, anti-apoptotitic drug has a possibility of new candidate for AGA. This study revealed RXM antagonized the in vitro inhibitory effect of IFN-γ on proliferation of keratinocytes and induction of apoptosis in murine and human hair bulb. RXM increases hair elongation and inhibits catagen-like changes induced in vitro with IFN-γ in murine and human hair follicles. Furthermore, topical 5% RXM solution effectively restores hair growth in about half of individuals with AGA without any local and systemic adverse effects. Therefore, RXM is new candidate as a hair restoration drug for AGA.     

PDGF isoforms induce and maintain anagen phase of murine hair follicles

BACKGROUND: It is known that platelet-derived growth factor (PDGF) receptors are expressed in hair follicle (HF) epithelium. OBJECTIVES: The aim of the present study was to clarify the effects of PDGF-AA and -BB on the cyclic growth of HFs. METHODS: PDGF-AA or -BB was injected into the dorsal skin of C3H mice during the second telogen phase once daily for five consecutive days, or PDGF-AA or -BB dissolved in hyaluronic acid was injected only once. In order to confirm the effects of different PDGF isoforms, anti-PDGF-AA antibody or anti-PDGF-BB antibody was injected just after each injection of PDGF-AA or -BB. In addition, anti-PDGF antibodies were injected into the skin of C3H mice during the second anagen phase once daily for 5 days. We studied expression of signaling molecules in the skin where anagen phase had been induced by PDGF injection by real-time RT-PCR. RESULTS: Both PDGF-AA and -BB injection experiments immediately induced the anagen phase of the hair growth cycle at the injection sites. The induction of anagen was interfered by anti-PDGF antibody treatment. Real-time RT-PCR using extracted RNA from the PDGF injected sites of skin samples showed upregulated expression of HF differentiation-related key signaling molecules, Sonic hedgehog (Shh), Lef-1 and Wnt5a. CONCLUSIONS: These results indicate that both PDGF-AA and -BB are involved in the induction and maintenance of the anagen phase in the mouse hair cycle. Local application of PDGF-AA and -BB might therefore prove to be an effective treatment option for alopecia associated with early catagen induction and elongated telogen phase.     

A comprehensive guide for the accurate classification of murine hair follicles in distinct hair cycle stages.

Numerous strains of mice with defined mutations display pronounced abnormalities of hair follicle cycling, even in the absence of overt alterations of the skin and hair phenotype; however, in order to recognize even subtle, hair cycle-related abnormalities, it is critically important to be able to determine accurately and classify the major stages of the normal murine hair cycle. In this comprehensive guide, we present pragmatic basic and auxiliary criteria for recognizing key stages of hair follicle growth (anagen), regression (catagen) and quiescence (telogen) in C57BL/6NCrlBR mice, which are largely based on previous work from other authors. For each stage, a schematic drawing and representative micrographs are provided in order to illustrate these criteria. The basic criteria can be employed for all mouse strains and require only routine histochemical techniques. The auxiliary criteria depend on the immunohistochemical analysis of three markers (interleukin-1 receptor type I, transforming growth factor-beta receptor type II, and neural cell-adhesion molecule), which allow a refined analysis of anatomical hair follicle compartments during all hair cycle stages. In contrast to prior staging systems, we suggest dividing anagen III into three distinct substages, based on morphologic differences, onset and progression of melanogenesis, and the position of the dermal papilla in the subcutis. The computer-generated schematic representations of each stage are presented with the aim of standardizing reports on follicular gene and protein expression patterns. This guide should become a useful tool when screening new mouse mutants or mice treated with pharmaceuticals for discrete morphologic abnormalities of hair follicle cycling in a highly reproducible, easily applicable, and quantifiable manner.     

Expression of classical and non-classical MHC class I antigens in murine hair follicles

Not all keratinocytes in human and rat hair follicles express MHC class I antigens (MHC I). In the present study, we report the first immunohistological profile of classical and non-classical MHC I expression in the skin of adolescent C57 BL-6 mice during the induced hair cycle. MHC I immunoreactivity (H-2^b, H-2D^b) is absent in the matrix and inner root sheath of growing (=anagen) hair follicles, and the dermal papillae are H-2^b negative during catagen and telogen. This lack of normal MHC I expression may serve to sequester potentially damaging autoantigens from immune recognition. In addition, we present the first evidence of non-classical MHC class I antigen expression in normal mammalian skin: during the entire hair cycle, the distal hair follicle shows strong Qa-2 immunoreactivity, which appears to be restricted to an epithelial follicle compartment densely populated by gamma-delta T cells with which Qa-2 molecules may interact as part of a primitive antibacterial defense system of the follicle. The murine hair cycle is an attractive model for dissecting the functional roles of H-2^b and Qa-2 molecules in hair biology and in related tissue-interaction systems.     

毛囊混合细胞在海藻酸钠支架上诱导毛囊重建

目的 探讨原代培养的毛囊外根鞘细胞、毛乳头细胞和成纤维细胞,采用不同接种顺序在体外和体内诱导毛囊形成.方法 将培养的毛囊外根鞘细胞(ORSC)、毛乳头细胞(DPC)和丝裂霉素干预后的成纤维细胞按一定比例制成细胞悬液,并按不同的接种顺序接种于海藻酸钠3D细胞支架上,构建毛囊的体外三维模型并培养8周,行HE染色光镜观察毛囊形成的情况;同时将该三维模型移植入bal/bcl裸鼠皮下体内培养8周,移植部位取材后分别行HE染色、免疫组化和电镜观察毛囊形成的情况.结果 体外构建的毛囊三维模型未见到角化物质及毛囊样结构;裸鼠皮下移植物HE染色可见细胞聚集成团,有呈环状排列的毛囊样结构,CK14,CK15、β1整合素和波形蛋白染色阳性;电镜下模型中可见贴附在支架上的毛囊细胞和红细胞.先接种用丝裂霉素干预的成纤维细胞于海藻酸钠3D细胞支架上培养1周后再接种DPC∶ORSC (1∶5)细胞悬液,裸鼠体内移植物HE染色不仅可见明显的毛囊样结构形成,而且形成毛囊样结构的数目较多.结论 模型中DPC保持了诱导毛囊形成的能力,ORSC保持了毛囊干细胞的特点.并明确了诱导毛囊形成的最佳细胞组合、接种顺序和比例,为体外构建含有毛囊的人工皮肤奠定了一定基础.     

Extracellular histones inhibit hair shaft elongation in cultured human hair follicles and promote regression of hair follicles in mice

Release of histone H4 in rat vibrissa dermal papilla (DP) cells exposed to sub‐toxic dose of colchicines has been recently reported. In addition, exposure to histone H4 has been reported to result in inhibited proliferation and reduced alkaline phosphatase (ALP) activity of cultured vibrissa DP cells. These findings prompted us to investigate the role of extracellular histones in hair growth using cultured human hair follicles and hair cycling using back skin of mice. We report here that exposure of cultured hair follicles to histone H4 and H2A resulted in significant inhibition of elongation of hair shafts, decreased expression of IGF‐1 and decreased expression and activity of ALP. Injection of histones into hypodermis of mice during anagen resulted in premature onset of catagen. Findings of the current study provide strong evidence suggesting the inhibitory role of extracellular histones in hair growth.     

中波紫外线诱导小鼠皮肤光损伤中miRNA141表达的研究

【摘要】 目的 探讨小室移植法重建小鼠毛囊,观察细胞成分对毛囊再生的影响。 方法 取0 ～ 2 d的C57BL/6乳鼠背部皮肤,胰酶消化后分离表真皮,再分离出毛囊上皮细胞。实验分表皮细胞混合毛囊胚芽组、真皮细胞组、表皮细胞混合毛囊胚芽 + 真皮细胞组、毛囊上皮细胞 + 真皮细胞组。用小室移植法接种于裸鼠背部,并于移植后1、2、4、8周观察变化,HE染色观察毛囊组织学形态。 结果 小鼠毛囊细胞移植1周时,背部小室开始脱落,伤口结痂;2周时除表皮细胞组外,另3组均长出了短小的毛发,镜下可见毛囊样结构;4周及8周时除表皮细胞组外,均长出了正常的毛发,表皮细胞与真皮细胞混合组及毛囊上皮细胞与真皮细胞混合组毛发生长情况良好,优于单独的真皮细胞组。 结论 毛囊细胞小室移植后可形成新的毛囊,上皮细胞及真皮细胞在毛囊重建中具有重要的作用。 【关键词】 毛囊; 毛囊重建; 鼠科     

Apoptosis as the mechanism of the involution of hair follicles in catagen transformation

Electron microscopy was performed on mouse skin to study the mechanism of the spontaneous involution of hair follicles during catagen. The reduction in follicles size appears to result from cell deletion by apoptosis, a distinct type of cell death with importance in tissue kinetics. These ultrastructural changes have been misinterpreted in the past as autophagic vacuole formation because of the prominent phagocytosis of the apoptotic fragments by adjacent, surviving cells of the hair follicle.     

Innovative liposomes as a transfollicular drug delivery system: penetration into porcine hair follicles

Liposomes had been widely used for drug delivery in the past. In this study, five different liposomes were used as a follicular delivery system in pig ear skin. The liposomes mainly differed in their sphere diameter, lipid composition, and surface charge. A novel class of liposomes being amphoteric in their charge behavior are compared to established anionic and cationic liposomes. Two different fluorescent dyes, hydrophilic carboxyfluoresceine or lipophilic curcumin, were enclosed in the liposomes and used as model drugs. The fluorescent dyes were also applied in a standard formulation for reference. The penetration depth of the dyes was measured by laser scanning microscopy in histological sections. One hour, 3, 5, and 7 days after application, biopsies were taken and the penetration depth into the hair follicle was measured in longitudinal sections. The liposomes showed a higher penetration depth compared to the standard formulation. The relative penetration depth of the dyes, applied in the standard formulation, averaged 30% of the full follicle length during the whole observation period, whereas the liposomal formulations penetrated considerably deeper into the hair follicles. Amphoteric and cationic liposomes reached an average relative penetration depth of approximately 70% of the full hair follicle length.     

Morphogenesis of chimeric hair follicles in engineered skin substitutes with human keratinocytes and murine dermal papilla cells

Engineered skin substitutes (ESS) have been used successfully to treat life‐threatening burns, but lack cutaneous appendages. To address this deficiency, dermal constructs were prepared using collagen‐glycosaminoglycan scaffolds populated with murine dermal papilla cells expressing green fluorescent protein (mDPC‐GFP), human dermal papilla cells (hDPC) and/or human fibroblasts (hF). Subsequently, human epidermal keratinocytes (hK) or hK genetically modified to overexpress stabilized β‐catenin (hK') were used to prepare ESS epithelium. After 10 days incubation at air–liquid interface, ESS were grafted to athymic mice and were evaluated for 6 weeks. Neofollicles were observed in ESS containing mDPC‐GFP, but not hDPC or hF, independent of whether or not the hK were genetically modified. Based on detection of GFP fluorescence, mDPC were localized to the dermal papillae of the well‐defined follicular structures of grafted ESS. In addition, statistically significant increases in LEF1, WNT10A and WNT10B were found in ESS with neofollicles. These results demonstrate a model for generation of chimeric hair in ESS.