Cultured dermal papilla cells of the rat vibrissa follicle. Proliferative activity, adhesion properties and reorganization of the extracellular matrix in vitro

Detecting the Mechanism behind the Transition from Fixed Two-Dimensional Patterned Sika Deer (Cervus nippon) Dermal Papilla Cells to Three-Dimensional Pattern

The hair follicle dermal papilla is critical for hair generation and de novo regeneration. When cultured in vitro, dermal papilla cells from different species demonstrate two distinguishable growth patterns under the conventional culture condition: a self-aggregative three dimensional spheroidal (3D) cell pattern and a two dimensional (2D) monolayer cell pattern, correlating with different hair inducing properties. Whether the loss of self-aggregative behavior relates to species-specific differences or the improper culture condition remains unclear. Can the fixed 2D patterned dermal papilla cells recover the self-aggregative behavior and 3D pattern also remains undetected. Here, we successfully constructed the two growth patterns using sika deer (Cervus nippon) dermal papilla cells and proved it was the culture condition that determined the dermal papilla growth pattern. The two growth patterns could transit mutually as the culture condition was exchanged. The fixed 2D patterned sika deer dermal papilla cells could recover the self-aggregative behavior and transit back to 3D pattern, accompanied by the restoration of hair inducing capability when the culture condition was changed. In addition, the global gene expressions during the transition from 2D pattern to 3D pattern were compared to detect the potential regulating genes and pathways involved in the recovery of 3D pattern and hair inducing capability.

Towards developing an organotypic model for the preclinical study and manipulation of human hair matrix-dermal papilla interactions

Organ culture of microdissected scalp hair follicles (HFs) has become the gold standard for human ex vivo hair research; however, availability is becoming very limited. Although various simplistic “HF-equivalent” in vitro models have been developed to overcome this limitation, they often fail to sufficiently mimic the complex cell–cell and cell–matrix interactions between epithelial and mesenchymal cell populations that underlie the specific growth processes occurring in a native HF. Here, we have attempted to overcome these limitations by developing a novel human hair research model that combines dermal papilla (DP) fibroblasts, cultured as 3-dimensional (3D) spheroids (DPS), with plucked anagen hair shafts (HS). We show that DPS express HF inductivity markers, such as alkaline phosphatase (ALP), versican and noggin, while plucked HSs retain substantial remnants of the anagen hair matrix. When cultured together, DPS adhere to and surround the plucked HS (HS-DPS), and significantly enhance HS expression of the differentiation marker keratin-85 (K85; p < 0.0001), while simultaneously decreasing the percentage of TUNEL + cells in the proximal HS (p = 0.0508). This simple model may offer a physiologically relevant first step toward evaluating HF differentiation in the human anagen hair matrix.

Isolation, culture and growth characteristics of dermal papilla cells from Rex rabbits

Dermal papilla cells (DPCs) is the key dermal component of the hair follicle that directly regulates hair follicle development, growth and regeneration. Successfully isolated and cultured DPCs of Rex rabbit could provide a good model for the study of hair follicle development mechanism in vitro. Skin samples were collected from 30-day old Rex rabbits and separated by combination of Dispase II and Collagenase D, separation, culture, and purification of DPCs. The morphology of DPCs in vitro was observed and the growth curve was drawn, the number of DPCs presented progressive increase in a logarithmic model between the 4^th day and the 7^th day. The results of immune chemical and immune fluorescence shown that α smooth muscle actin (α-SMA) and versican were positive in cells. Growth character of the passages 3 (P3), P6, P9 and P12 DPCs were observed using MTT at 24 h, 48 h, 72 h, 96 h, 120 h and 144 h. The cell density of P12 was lower than P3 (P < 0.05); the flow cytometric analysis showed that DPCs at resting state/first gap (G0/G1) stage of P3 was higher than P12 (P < 0.05), and second gap/mitosis (G2/M) stage of P3 was lower than P12 (P < 0.05). However, the DPCs of P12 present triangular or short fusiform, retaining their unique aggregative growth characteristics. This results shown that the DPCs properties of P12 from Rex rabbits, still fit functional research in vitro. In conclusion, we successfully established the culturing condition of DPCs from Rex rabbits, and provide a material for studying the molecular mechanism of hair follicle development.

Preparation of hair beads and hair follicle germs for regenerative medicine

Hair regenerative medicine is a promising approach for hair loss, during which autologous follicular stem cells are transplanted into regions of hair loss to regenerate hairs. Because cells transplanted as a single cell suspension scarcely generate hairs, the engineering of three-dimensional (3D) tissues before transplantation has been explored to improve this process. Here, we propose an approach to fabricate collagen-enriched cell aggregates, named hair beads (HBs), through the spontaneous constriction of cell-encapsulated collagen drops. Mouse embryonic mesenchymal cells or human dermal papilla cells were encapsulated in 2-μl collagen microgels, which were concentrated >10-fold in volume during 3 days of culture. Interestingly, HB constriction was attributed to attraction forces driven by myosin II and involved the upregulation of follicular genes. Single HBs with epithelial cells seeded in U-shaped microwells formed dumbbell-like structures comprising respective aggregates (named bead-based hair follicle germs, bbHFGs), during 3 days of culture. bbHFGs efficiently generated hair follicles upon intracutaneous transplantation into the backs of nude mice. Using an automated spotter, this approach was scalable to prepare a large number of bbHFGs, which is important for clinical applications. Therefore, this could represent a robust and practical approach for the preparation of germ-like tissues for hair regenerative medicine.

Lactoferrin promotes hair growth in mice and increases dermal papilla cell proliferation through Erk/Akt and Wnt signaling pathways

Hair loss affects men and women of all ages. Dermal papilla (DP) plays a crucial role in regulating the growth and cycling of hair follicles. Lactoferrin (LF) exhibits a wide range of biological functions, including antimicrobial activity and growth regulation. However, its effect on DP and its role in hair growth remain unknown. In this study, we found that bovine LF (bLF) promoted the proliferation of DP cells and enhanced the phosphorylation of Erk and Akt. The bLF-mediated proliferation was significantly blocked by the Erk phosphorylation inhibitor PD98059 or the Akt phosphorylation inhibitor LY294002. Moreover, biotin-labeled bLF could bind to DP cells, and the binding was independent of lipoprotein receptor-related protein 1, a known LF receptor. Importantly, bLF stimulated hair growth in both young and aged mice. Moreover, we also found that bLF significantly induced the expression of Wnt signaling-related proteins, including Wnt3a, Wnt7a, Lef1, and β-catenin. The bLF-mediated DP cell proliferation could be significantly reversed by the Wnt pathway inhibitor XAV939. Our findings suggest that bLF promotes hair growth in mice and stimulates proliferation of DP cells through Erk/Akt and Wnt signaling pathways. This study highlights a great potential of the use of bLF in developing drugs to treat hair loss.

Role of Annexin A2 isoform 2 on the aggregative growth of dermal papillae cells

The dermal papilla is a major component of hair, which signals the follicular epithelial cells to prolong the hair growth process. Human Annexin A2 was preliminarily identified by two-dimensional gel electrophoresis (2-DE), MALDI-TOF-MS and database searching. The aim of the present study was to explore the role of Annexin A2 in the aggregative growth of dermal papillae cells (DPC). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were adopted to detect the expression of Annexin A2. And siRNA technique was used to suppress the expression of Annexin A2. Construction of over-expression vector was used to up-regulate the expression of Annexin A2. Cell Counting Kit 8 (CCK-8) and proliferating cell nuclear antigen (PCNA) were taken to detect the proliferation of DPC. The expression of Annexin A2 mRNA was up-regulated in passage 3 DPC compared with passage 10 DPC by RT-PCR. In line with the results at the mRNA level, Western blot analysis revealed that Annexin A2 isoform 2 was up-regulated significantly in passage 3 DPC compared with passage 10 DPC. The Annexin A2 isoform 2 siRNA was synthesized and transfected into passage 3 DPC. RT-PCR data showed the mRNA expression of Annexin A2 isoform 2 was suppressed in passage 3 DPC. Western blot results showed the expression level of Annexin A2 isoform 2 and PCNA were suppressed in passage 3 DPC. CCK-8 results showed that the proliferation of passage 3 DPC was suppressed (P < 0.05). Recombinant plasmid PLJM-Annexin A2 isoform 2-expression vector were constructed and were transfected into passage 10 DPC. RT-PCR data showed the mRNA expression of Annexin A2 isoform 2 was up-regulated in passage 10 DPC. Western blot results showed the expression level of annexin A2 isoform 2 and PCNA were up-regulated in passage 10 DPC. CCK-8 assay showed the proliferation of DPC was stimulated compared with control group (*P < 0.05). Our study proved that Annexin A2 isoform 2 may participate in regulating the proliferation of DPC and may be related to aggregative growth of dermal papilla cells. Therefore, our study suggests that Annexin A2 may be linked to hair follicle growth cycle.

Multimodal label-free imaging of living dermal equivalents including dermal papilla cells

BACKGROUND

Despite the significant progress in the development of skin equivalents (SEs), the problem of noninvasively assessing the quality of the cell components and the collagen structure of living SEs both before and after transplantation remains. Undoubted preference is given to in vivo methods of noninvasive, label-free monitoring of the state of the SEs. Optical bioimaging methods, such as cross-polarization optical coherence tomography (CP OCT), multiphoton tomography (MPT), and fluorescence lifetime imaging microscopy (FLIM), present particular advantages for the visualization of such SEs.

METHODS

In this study, we simultaneously applied several visualization techniques for skin model examination. We investigated the structure and quality of dermal equivalents containing dermal papilla (DP) cells and dermal fibroblasts (FBs) using CP OCT, MPT, and FLIM. Both the energy metabolism of the cell components and the structuring of the collagen fibrils were addressed.

RESULTS

Based on the data from the fluorescence lifetimes and the contributions of protein-bound NAD(P)H, a bias toward oxidative metabolism was indicated, for the first time, in both the DP cells and FBs on day 14 of SE cultivation. The CP OCT and MPT data also indicated that both DP cells and FBs structured the collagen gel in a similar manner.

CONCLUSION

In this study, multimodal label-free imaging of the structure and quality of living dermal equivalents was implemented for the first time with the use CP OCT, MPT, and FLIM of NAD(P)H. Our data suggest that the combination of different imaging techniques provides an integrated approach to data acquisition regarding the structure and quality of dermal equivalents, minimizes the potential disadvantages of using a single method, and provides an ideal information profile for clinical and research applications.

Therapeutic role of human hepatocyte growth factor (HGF) in treating hair loss

Hepatocyte growth factor (HGF) is a paracrine hormone that plays an important role in epithelial-mesenchymal transition. HGF secreted by mesenchymal cells affects many properties of epithelial cells, such as proliferation, motility, and morphology. HGF has been reported to promote follicular growth. The purpose of the present study is to investigate the therapeutic role of HGF in hair loss treatment. A recombinant vector containing the human HGF (hHGF) gene (pTARGET-hHGF) was constructed, and the expression of hHGF in vitro was quantitatively and qualitatively evaluated. The effect of hHGF on hair growth was tested in mice, and results demonstrated that pTARGET-hHGF was successfully delivered into fibroblasts in vitro leading to a high expression of hHGF. Local injections of the pTARGET-hHGF recombinant vector into mice resulted in multiple beneficial effects compared to placebo, including faster hair regeneration, improved follicle development, and significantly increased HGF receptor (HGF-R). In conclusion, we have established a nonviral vector of hHGF which could be utilized to manipulate the sheath fibroblasts surrounding hair follicles (HF), thereby stimulating hair regeneration.

Oxidative stress-associated senescence in dermal papilla cells of men with androgenetic alopecia

Dermal papilla cells (DPCs) taken from male androgenetic alopecia (AGA) patients undergo premature senescence in vitro in association with the expression of p16(INK4a), suggesting that DPCs from balding scalp are more sensitive to environmental stress than nonbalding cells. As one of the major triggers of senescence in vitro stems from the cell "culture shock" owing to oxidative stress, we have further investigated the effects of oxidative stress on balding and occipital scalp DPCs. Patient-matched DPCs from balding and occipital scalp were cultured at atmospheric (21%) or physiologically normal (2%) O2. At 21% O2, DPCs showed flattened morphology and a significant reduction in mobility, population doubling, increased levels of reactive oxygen species and senescence-associated β-Gal activity, and increased expression of p16(INK4a) and pRB. Balding DPCs secreted higher levels of the negative hair growth regulators transforming growth factor beta 1 and 2 in response to H2O2 but not cell culture-associated oxidative stress. Balding DPCs had higher levels of catalase and total glutathione but appear to be less able to handle oxidative stress compared with occipital DPCs. These in vitro findings suggest that there may be a role for oxidative stress in the pathogenesis of AGA both in relation to cell senescence and migration but also secretion of known hair follicle inhibitory factors.

Controllable production of transplantable adult human high-passage dermal papilla spheroids using 3D matrigel culture

We have succeeded in culturing human dermal papilla (DP) cell spheroids and developed a three-dimensional (3D) Matrigel (basement membrane matrix) culture technique that can enhance and restore DP cells unique characteristics in vitro. When 1 × 10(4) DP cells were cultured on the 96-well plates precoated with Matrigel for 5 days, both passage 2 and passage 8 DP cells formed spheroidal microtissues with a diameter of 150-250 μm in an aggregative and proliferative manner. We transferred and recultured these DP spheroids onto commercial plates. Cells within DP spheres could disaggregate and migrate out, which was similar to primary DP. Moreover, we examined the expression of several genes and proteins associated with hair follicle inductivity of DP cells, such as NCAM, Versican, and α-smooth muscle actin, and confirmed that their expression level was elevated in the spheres compared with the dissociated DP cells. To examine the hair-inducing ability of DP spheres, hair germinal matrix cells (HGMCs) and DP spheres were mixed and cultured on Matrigel. Unlike the dissociated DP cells and HGMCs cocultured in two dimensions, HGMCs can differentiate into hair-like fibers under the induction of the DP spheres made from the high-passage cells (passage 8) in vitro. We are the first to show that passage 3 human HGMCs differentiate into hair-like fibers in the presence of human DP spheroids. These results suggest that the 3D Matrigel culture technique is an ideal culture model for forming DP spheroids and that sphere formation partially models the intact DP, resulting in hair induction, even by high-passage DP cells.

Dermal papilla cells induce keratinocyte tubulogenesis in culture

The ability of dermal papilla (DP) cells to induce hair growth was reported in many studies. However, early stages of hair follicle development and signals that govern this process are poorly understood. Therefore, an in vitro model may be a convenient system to study epithelial-mesenchymal interactions and early stages of epidermal morphogenesis, especially in humans. To investigate the role of DP cells in epidermal morphogenesis we modified the method of isolation of DP cells from hair follicle of human scalp and developed the three-dimensional model of epidermal morphogenesis. Isolated DP cells were able to differentiate in adipogenic and osteogenic directions and retained activity of alkaline phosphatase (AP) for seven passages in culture. DP cells were able to induce tubule-like structures in three-dimensional model in vitro and to reorganize collagen matrix. Prolonged cultivation of DP cells has been a big problem because of the loss of hair follicle-inducing ability and growth activity after several passages. To solve this problem we immortalized DP cells by the transfection of the human telomerase reverse transcriptase cDNA (hTERT). Immortalized DP-hTERT cells retained AP activity and demonstrated low ability to osteogenic differentiation. The conditioned medium collected from actively proliferated cells as well as DP-hTERT cells themselves were capable to induce tubulogenesis after prolonged keratinocyte cultivation.

The enhancement of dermal papilla cell aggregation by extracellular matrix proteins through effects on cell-substratum adhesivity and cell motility

Generally, cells tend to aggregate on a substratum with lower cell adhesivity. However, it also leads to compromised cell growth and higher cell loss after seeding. This study is aimed at tackling this dilemma by extracellular matrix (ECM) protein coating of a lower adhesive substratum poly(ethylene-co-vinyl alcohol) (EVAL) that has been shown to facilitate hair follicle dermal papilla (DP) spheroid formation. We found that coating with either fibronectin (Fn), collagen I, or collagen IV yields higher adhesivity and cell growth than that with laminin. However, cells can only aggregate on uncoated or Fn-coated EVAL. Quantitatively, Fn coating increases the number of spheroids by 67%. Analysis of cell migration reveals that collagen I, collagen IV and laminin coatings reduce cell motility, while Fn coating keeps cells highly motile. Inhibition of cell migration hinders spheroid formation. In addition, disruption of Fn function does not significantly compromise intercellular adhesion. Hence, Fn enhances cell aggregation by enhancing cell attachment, cell growth and cell motility. Our study demonstrates that intercellular organization as spheroids or flat monolayers is switchable by specific ECM protein coating and preserving cell motility is vital to cell aggregation. In addition to generation of spheroidal DP microtissues for hair follicle regeneration and large-scale production of aggregates of other cells, this strategy can help to regulate the tissue-substrate adhesivity and tissue spreadability on the surface of implantable materials.

TGF-beta is specifically expressed in human dermal papilla cells and modulates hair folliculogenesis

Dermal papilla cells (DPCs) in the mammalian hair follicle have been shown to develop hair follicles through epithelial-mesenchymal interactions. A cell therapy to regenerate human hair is theoretically possible by expanding autologous human DPCs (hDPCs) and transplanting them into bald skin, though much remains to be overcome before clinical success. In this study, we compared gene signatures of hDPCs at different passages and human dermal fibroblasts, and found transforming growth factor (TGF)-beta(2) to be highly expressed in cultured hDPCs. Keratinocyte conditioned medium, which is known to help preserve the hair-inducing capacity of hDPCs, up-regulated TGF-beta(2) expression of hDPCs and also enhanced their alkaline phosphatase (ALP) activity, a known index for hair-inductive capacity. Through screening of components secreted from keratinocytes, the vitamin D(3) analogue was found to promote TGF-beta(2) expression and ALP activity of hDPCs. In animal hair folliculogenesis models using rat epidermis and expanded hDPCs, inhibition of TGF-beta(2) signalling at the ligand or receptor level significantly impaired hair folliculogenesis and maturation. These results suggest an important role for TGF-beta(2) in hair follicle morphogenesis and provide insights into the establishment of future cell therapies for hair regrowth by transplanting expanded DPCs.

Identification of proteins involved in aggregation of human dermal papilla cells by proteomics

BACKGROUND

The dermal papilla is a major component of hair, which signals the follicular epithelial cells to prolong the hair growth process. To date, little is known about the significance of the specific protein(s) express in the dermal papilla cells (DPC) with regard to their aggregative behaviour.

OBJECTIVES

To identify proteins involved in aggregative behaviour of DPC, we comparatively analyzed the proteome of cells with and without aggregative behaviour.

METHODS

A series of methods were used, including two-dimensional gel electrophoresis (2-DE), PDQuest software analysis of 2-DE gels, peptide mass fingerprinting based on matrix-assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-TOF-MS), and NCBInr database searching, to separate and identify differentially expressed proteins. Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) were used to validate the differentially expressed proteins.

RESULTS

Image analysis revealed that averages of 618+/-22 and 568+/-47 protein spots were detected in passages 3 and 10 DPC, respectively. Twenty-four differential protein spots were measured with MALDI-TOF-MS. A total of 17 spots yielded good spectra, and 15 spots matched with known proteins after database searching. Western blotting confirmed that heat shocking protein 70 was up-regulated in passage 3 DPC. Over-expression of mitochondrial ribosomal protein S7 was confirmed by RT-PCR, indicating that they are involved in aggregation of DPC through some signaling pathway.

CONCLUSIONS

The clues provided by the comparative proteome strategy utilized here will shed light on molecular mechanisms of DPC in aggregative behaviour.

Treatment of alopecia by transplantation of hair follicle stem cells and dermal papilla cells encapsulated in alginate gels

The affected individual of hair loss demands help, because hair is viewed as a sign of youth and good health. Nowadays treatment of alopecia includes drug therapy and hair transplantation. Some drugs may promote hair growth, at least temporarily, but the treatment is effective only in milder alopecia, instead of extensive alopecia. Furthermore, the side effect of long period medication could not be avoided. Hair transplantation involves harvesting small pieces of hair-bearing scalp grafts from a donor site and relocating them to a bald area. This method does not increase the number of existing hairs, but only redistributes them. The operation is sophisticated and time-consuming, thus the patient suffers a lot during the process. The discovery of hair follicle stem cells (FSC) brings gospel to the affected individual of hair loss because of its capacity of generating new hair when they interact with mesenchymal dermal papilla cells (DPC). Besides, both FSC and DPC have strong proliferative capacity and the patient's own cells could be expanded considerably in vitro. Thus we hypothesize that the microencapsulation of the two kinds of cells in alginate gels could be implanted into the bald scalp of the patient since alginate gels is effective in cell transplantation. The strategy may provide a more convenient and valid alternative to hair loss if the hypothesis proved to be practical.

Differences in Expression of Specific Biomarkers Distinguish Human Beard from Scalp Dermal Papilla Cells

Androgen exposure stimulates the growth of beard hair follicles. The follicle dermal papilla appears to be the site of androgen action; however, the molecular mechanisms that regulate this process are not well understood. In an attempt to identify genes that contribute to the androgen-responsive phenotype, we compared gene expression patterns in unstimulated and androgen-treated cultured human dermal papilla cells isolated from beard (androgen-sensitive) and occipital scalp (androgen-insensitive) hair follicles. Through this analysis, we identified three genes that are expressed at significantly higher levels in beard dermal papilla cells. One of these genes, sfrp-2 has been identified as a dermal papilla signature gene in mouse pelage follicles. Two of these genes, mn1 and atp1beta1, have not been studied in the hair follicle. A fourth, fibulin-1d, was slightly upregulated in beard dermal papilla cells. The differences in the expression of these genes in cultured beard and scalp dermal papilla cells reflected similar differences in microdissected dermal papilla isolated from intact beard and scalp follicles. Our findings introduce potentially novel signaling pathways in dermal papilla cells. In addition, this study supports that cultured dermal papilla cells provide a cell-based model system that is reflective of the biology of in vivo hair follicle cells.

Human Scalp Dermal Papilla and Fibrous Sheath Cells have a different expression profile of Matrix Metalloproteinases in vitro when compared to Scalp Dermal Fibroblasts

The dermal papilla is a cluster of specialised mesenchymal cells at the bottom of the mammalian hair follicle, embedded in a loose extracellular matrix. These cells have the capability to induce and support hair growth via close epithelial-mesenchymal interactions with the keratinocytes surrounding the hair matrix. The extracellular matrix of the dermal papilla differs markedly from the interfollicular matrix and plays a key role in the maintenance of hair growth. In this study we investigated the expression pattern and activity of matrix metalloproteinases (MMP) and their tissue inhibitor in in vitro cultures of cells derived from scalp dermal papilla and fibrous sheath. Expression and activity of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2 and MT1-MMP were analysed in those cells cultured in contact with one of the relevant protein component of the dermal matrix, collagen type I as well as in monolayer. Zymographic analysis showed activation of MMP-2 in all cells grown in three-dimensional collagen lattices whereas MMP-9 was activated only in three-dimensional collagen cultures of dermal fibroblasts and weakly in follicular cells. Expression of MMP-1, TIMP-1, TIMP-2 and MT1-MMP was similar in all cells, in both culture conditions, whereas expression of MMP-3 was absent in dermal papilla cells. In addition to a series of reported morphological and functional differences between dermal fibroblasts and the dermal mesenchyme-derived cells of the hair follicle, we reported differences in MMP expression in dermal papilla and fibrous sheath cells within the mesenchymal population of the hair follicle.

Establishment of cadherin-based intercellular junctions in the dermal papilla of the developing hair follicle

During hair follicle development, mesenchymal cells aggregate to form the dermal papilla with hair-inducing activity. However, the cellular mechanisms underlying the aggregative behavior of dermal papilla cells are less known. The present study demonstrates that cadherin-based intercellular junctions interconnect dermal papilla cells in developing hair follicles of mice. It is shown that as mesenchymal cells aggregate to be surrounded by epithelium in developing hair follicles, cadherin-11 comes to exhibit the dotted patterns of distribution. The appearance of the dot-like distribution of the molecule is concomitant with the formation of intercellular junctions in the mesenchymal aggregate, which make a tightly packed population of cells with little extracellular space. At later stages of the development, although extracellular space reappears in the dermal papilla, the cells remain interconnected by well-developed intercellular junctions, where cadherin-11 as well as beta-catenin is localized. Taking into consideration the normal hair development in cadherin-11 mutant mice, it might be that multiple cadherins are responsible for the establishment of intercellular junctions in the dermal papilla and serve to maintain the aggregative behavior of the cells.

Primary cell culture and morphological characterization of canine dermal papilla cells and dermal fibroblasts

Skin biopsies were taken from female dogs, the primary hair follicles isolated and the dermal papilla dissected. After incubation in supplemented Amniomax complete C100 medium in 24-well culture plates, the dermal papilla cells (DPC) grew to confluence within 3 weeks. Thereafter, they were subcultivated every 7 days. Dermal fibroblast (DFB) cultures were established by explant culture of interfollicular dermis in serum-free medium, where they reached confluence in 10 days. They were subcultivated every 5 days. For immunohistochemistry, cells were grown on cover slips for 24 h, fixed and stained with antibodies against collagen IV and laminin. DPC showed an aggregative growth pattern and formation of pseudopapillae. Intensive staining for collagen IV and laminin could be observed until the sixth passage. DFB grew as branching, parallel lines and showed only weak staining for collagen IV and laminin.