Human Dermal Cells Research Articles

Modulation of c-jun and c-fos Transcription by UVB and UVA Radiations in Human Dermal Fibroblasts and KB Cells

Modulation of c-jun and c-fos Transcription by UVB and UVA Radiations in Human Dermal Fibroblasts and KB Cells

Cultivating human dermal papilla cells efficiently on cytodex-3 microcarriers

目的 探讨用微载体培养技术进行人毛乳头细胞高效扩增的培养方法,以满足对毛乳头细胞的大量需求.方法 采用Cytodex-3为培养载体进行人第3代毛乳头细胞的微载体培养,定期观察培养液颜色的变化,采用苔盼蓝染色进行活细胞计数,倒置显微镜下观察生长状况.将微载体上消化的细胞进行传统培养,观察细胞生长情况,甲苯胺蓝染色,细胞免疫组织化学染色.结果 培养至第12天,微载体上细胞数量最多,并且细胞聚集成团,类似毛乳头样结构.利用这时的细胞进行普通培养,仍然表现出凝集性生长特点,细胞呈异染性,免疫组织化学染色阳性.结论 利用Cytodex-3培养可以收获大量具有生物活性的毛乳头细胞。

Restructuring skin equivalents with human hair follicle orscs and fibroblasts

Background: The bulge region, a portion of the outer root sheath (ORS), contains the hair follicle stem cells, which show multipotency to differentiate into almost all epithelial cell types. To produce an improved quality skin equivalent (SE), we established a rapid, easy and effective three-dimensional SE model on the basis of human dermal fibroblasts, collagen-GAG matrix (DE) and ORS cells (ORSCs).

Growth Factor Modulation of Fibroblast Proliferation, Differentiation, and Invasion: Implications for Tissue Valve Engineering

We have previously shown that transforming growth factor-beta1 (TGF-beta1) stimulates transdifferentiation of fibroblasts into smooth muscle alpha-actin (alpha-SMA) positive myofibroblasts. However, TGF-beta, as such, is unsuitable for effective population of a heart valve matrix, because it dose-dependently inhibits growth of fibroblasts. The aim of this study was to investigate combinations of other growth factors with TGF-beta to stimulate the proliferation of suitably differentiated cells and to enhance their invasion into aortic valve matrices. Human dermal mesenchymal cells (hDMC1.1) were treated with combinations of growth factors to stimulate these cells to trans-differentiate into myofibroblasts, to proliferate, and to invade. Growth factors were chosen after expression of their respective receptors was confirmed in hDMC1.1 using reverse transcriptase polymerase chain reaction. We combined TGF-beta with several growth factors such as insulin-like growth factor (IGF-1, IGF-2), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF-AA, PDGF-BB, and PDGFAB). Nuclear Ki67 staining, MTT assay, and cell counting revealed that only EGF and bFGF were capable of overcoming TGF-beta-induced growth inhibition. However, bFGF but not EGF inhibited TGF-beta-induced alpha-SMA expression, as evidenced by immuno-cytochemistry and Western blotting. A growth factor cocktail (TGF-beta, EGF, bFGF) has been established that maintains TGF-beta-induced trans-differentiation but overcomes TGF-beta-induced growth inhibition while stimulating fibroblast proliferation and invasion.

Phlorotannins in Ecklonia cava extract inhibit matrix metalloproteinase activity

Matrix metalloproteinase (MMP) inhibitors have been identified as potential therapeutic candidates for metastasis, arthritis, chronic inflammation and wrinkle formation. For the first time here we report a detailed study on the inhibitory effects of phlorotannins in brown algae, Ecklonia cava (EC) on MMP activities in cultured human cell lines. A novel gelatin digestion assay could visualize complete inhibition of bacterial collagenase-1 activity at 20 μg/ml of EC extract during preliminary screening studies. Sensitive fluorometric assay revealed that EC extract can specifically inhibit both MMP-2 and MMP-9 activities significantly ( P < 0.001) at 10 μg/ml. In addition, artificially induced activities of MMP-2 and MMP-9 in human dermal fibroblasts and HT1080 cells were inhibited by EC extract in a more or less similar manner to the positive control doxycycline. Even though the expression levels of MMPs differ from one cell type to the other, gelatin zymography clearly revealed that both MMP expression and activity in cells can be inhibited by EC extract. More interestingly, EC extract did not exert any cytotoxic effect even at 100 μg/ml anticipating its potential use as a safe MMP inhibitor.

Development and Characterization of an Acellular Human Pericardial Matrix for Tissue Engineering

This study aimed to produce an acellular human tissue scaffold with a view to recellularization with autologous cells to produce a tissue-engineered pericardium that can be used as a patch for cardiovascular repair. Human pericardia from cadaveric donors were treated sequentially with hypotonic buffer, SDS in hypotonic buffer, and a nuclease solution. Histological analysis of decellularized matrices showed that the human pericardial tissue retained its histioarchitecture and major structural proteins. There were no whole cells or cell fragments. There were no significant differences in the hydroxyproline (normal and denatured collagen) and glycosaminoglycan content of the tissue before and after decellularization (p > 0.05). There were no significant changes in the ultimate tensile strength after decellularization (p > 0.05). However, there was an increased extensibility when the tissue strips were cut parallel to the visualized collagen bundles (p = 0.005). No indication of contact or extract cytotoxicity was found when using human dermal fibroblasts and A549 cells. In summary, successful decellularization of the human pericardium was achieved producing a biocompatible matrix that retained the major structural components and strength of the native tissue.

Homing and Function of Human Skin γδ T Cells and NK Cells: Relevance for Tumor Surveillance

Normal (noninflamed) human skin contains a network of lymphocytes, but little is known about the homing and function of these cells. The majority of alphabeta T cells in normal skin express CCR8 and produce proinflammatory cytokines. In this study we examined other subsets of cutaneous lymphocytes, focusing on those with potential function in purging healthy tissue of transformed and stressed cells. Human dermal cell suspensions contained significant populations of Vdelta1(+) gammadelta T cells and CD56(+)CD16(-) NK cells, but lacked the subsets of Vdelta2(+) gammadelta T cells and CD56(+)CD16(+) NK cells, which predominate in peripheral blood. The skin-homing receptors CCR8 and CLA were expressed by a large fraction of both cell types, whereas chemokine receptors associated with lymphocyte migration to inflamed skin were absent. Neither cell type expressed CCR7, although gammadelta T cells up-regulated this lymph node-homing receptor upon TCR triggering. Stimulation of cutaneous Vdelta1(+) gammadelta T cell lines induced secretion of large amounts of TNF-alpha, IFN-gamma, and the CCR8 ligand CCL1. In contrast to cutaneous alphabeta T cells, both cell types had the capacity to produce intracellular perforin and displayed strong cytotoxic activity against melanoma cells. We therefore propose that gammadelta T cells and NK cells are regular constituents of normal human skin with potential function in the clearance of tumor and otherwise stressed tissue cells.

Activation of Src by inhibition of Csk does not decrease endothelial barrier function

Endothelial barrier function in the vasculature is known to be tightly regulated by the adherens junction (AJ). Recent studies have suggested that Src phosphorylation of AJ proteins contributes to a decrease in endothelial barrier function following cardiac ischemia and stroke. We sought to develop an in vitro model of Src activation in order to determine the mechanism of AJ phosphorylation, particularly p120, in Src-induced loss of barrier function. In these studies we activated endogenous Src by expressing a dominant negative form of c-terminal-src kinase (DN-Csk), a kinase known to inactivate Src by phosphorylation of tyrosine 527. Indeed, expression of DN-Csk in confluent human lung or human dermal microvascular cells activated endogenous Src as shown by increases in the dephosphorylation of tyrosine 527 and phosphorylation of tyrosine 416. In addition expression of DN-Csk resulted in a time dependent increase in global tyrosine phosphorylation including phosphorylation of paxillin, a protein found in cell-matrix AJs. Surprisingly, we found that increased Src activation following expression of DN-Csk is not sufficient to cause a loss of barrier function in endothelial cells. These results suggest that the context of Src activation is critical to modulating endothelial barrier function and suggests that Csk may play a greater role in regulation of cell-matrix junctions, as shown by paxillin phosphorylation, than at cell-cell junctions. K02-HL-04332; R01-HL-68079.

UVA Radiation Impairs Phenotypic and Functional Maturation of Human Dermal Dendritic Cells

There is now strong evidence that the ultraviolet A (UVA) part of the solar spectrum contributes to the development of skin cancers. Its effect on the skin immune system, however, has not been fully investigated. Here, we analyzed the effects of UVA radiation on dermal dendritic cells (DDC), which, in addition, provided further characterization of these cells. Dermal sheets were obtained from normal human skin and irradiated, or not, with UVA at 2 or 12 J per cm2. After a 2 d incubation, the phenotype of emigrant cells was analyzed by double immunostaining and flow cytometry. Results showed that migratory DDC were best characterized by CD1c expression and that only few cells co-expressed the Langerhans cell marker Langerin. Whereas the DC extracted from the dermis displayed an immature phenotype, emigrant DDC showed increased expression of HLA-DR and acquired co-stimulation and maturation markers. We showed here that UVA significantly decreased the number of viable emigrant DDC, a process related to increased apoptosis. Furthermore, UVA irradiation impaired the phenotypic and functional maturation of migrating DDC into potent antigen-presenting cells, in a concentration-dependent manner. The results provide further evidence that UVA are immunosuppressive and suggest an additional mechanism by which solar radiation impairs immune response.

Interleukin-1α–induced proteolytic activation of metalloproteinase-9 by human skin

Increased activity of matrix metalloproteinase-9 (MMP-9) has been well documented in many diseases associated with inflammation, such as chronic wounds, bullous pemphigoid, liver failure, and tumor metastases. The mechanism for the proteolytic activation of pro-MMP-9 in human tissue still remains unknown. We investigated this mechanism through reconstitution of an inflammatory condition in normal human skin, and epidermal and dermal cells derived from skin. Normal human skin was cultured with exogenous cytokines associated with inflammation and tissue repair. MMP-9 induction and activation were measured, and potential mechanisms were probed by inhibitors. Pathophysiologic concentrations of interleukin (IL)-1alpha rapidly induced pro-MMP-9 synthesis by human skin. In contrast, IL-1-induced activation of pro-MMP-9 was a slow process, which required 3 days. Tumor growth factor-beta induced pro-MMP-9 but failed to promote activation of the precursor. When the skin was stimulated with the combination of tumor growth factor-beta and IL-1alpha, substantial induction and activation of pro-MMP-9 occurred. This IL-1 induced activation of pro-MMP-9 was observed in intact skin but not in isolated dermal fibroblasts or keratinocytes. IL-1-induced activation of pro-MMP-9 was inhibited by chymostatin, a chymotrypsinlike proteinase inhibitor. Furthermore, IL-1alpha decreased tissue inhibitor of metalloproteinase 1 without changing MMP-9 activator activity. The proteolytic activation of pro-MMP-9 in skin inflammatory diseases likely occurs via a pathway including IL-1alpha. The activation is mediated by downregulation of tissue inhibitor of MMP-1 and involves an as yet unidentified chymotrypsinlike proteinase.

Biodegradable aliphatic polyester ionomers.

A series of polyester-based ionomers containing dimethyl 5-sulfoisophthalate sodium salt (DMSI) with up to 5 mol-% diacid units was synthesized by two-step polycondensation. Furthermore a polylactic acid (PLA) was modified by introducing poly(ethylene-co-methacrylic acid) ionomers with different ion groups, such as Na, Li, and Zn, using the melt blending method. This review examines the effect of the ionic group on the dynamic mechanical properties, melt rheology, crystallization behavior, degradation behavior, and biocompatibility with human dermal cells, as well as the nucleating effect of poly(ethylene-co-methacrylic acid) ionomer in PLA.

Vascular and Biology 01

Background: Endothelin-1 (ET-1) is a 21 amino acid peptide with vasoconstrictor and mitogenic properties. We observed that ET-1 is expressed around areas of angiogenesis in ischaemic skeletal muscle, and sought to determine whether ET-1 provides an angiogenic stimulus to human microvascular cells. Methods: Human dermal microvascular cells (HMEC-1) were grown on growth factor reduced Matrigel, with or without ET-1 at various concentrations. Synergy with the angiogenic factor vascular endothelial growth factor (VEGF) was sought by co-adding ET-1 with VEGF. In addition, we measured the effects of selective inhibitors of the ET-1 receptor. Angiogenesis was measured after 24-h treatment by visual analysis of microvessel growth and by scanning the mean optical density of images of the angiogenic field. Results: ET-1 enhanced angiogenesis in the presence of VEGF (P < 0.02). The ET(B) receptor antagonist BQ788 suppressed angiogenesis below basal levels (P < 0.04), whereas the ET(A) receptor antagonist had no effect. Microvascular cells were found to release ET-1 when grown on Matrigel, with enhancement following treatment with VEGF. Conclusions: These data suggest that in human microvascular cells, ET-1 is an important autocrine growth factor, acting downstream and in concert with VEGF to stimulate angiogenesis. We suggest that the mitogenic properties of ET-1 are ET(B) mediated, unlike the effects on vascular tone, which are ET(A) mediated. The separation of these effects might provide benefit to patients with peripheral vascular disease, where selective ET(A) receptor antagonists could promote vasodilatation whilst preserving the ET(B) mediated angiogenic effects.

In vitro cytotoxicity testing with fluorescence-based assays in cultured human lung and dermal cells.

An in vitro study using human cultured cells was conducted to determine the reliability of fluorescence-based cell viability indicators with traditional in vitro cytotoxicity testing methods. Human lung epithelial carcinoma (A549) cells, and human embryonic skin (WS1) and lung (HFLI) fibroblasts were studied in culture to evaluate their potential to screen for cytotoxicity and to compare to previous protocols conducted in our laboratory. Confluent monolayers were incubated in the absence or presence of increasing concentrations of test chemicals for 24 h, and fluorescent-labeled probes were used to assess toxicity. Eight chemicals, including mercuric chloride, copper sulfate, sodium fluoride, thioridazine HCl, paraquat, amitriptyline-HCl, verapamil-HCl and chloroquine sulfate, were tested with each cell line using calcein-AM and Sytox. The data suggest that fluorescent probes are sensitive indicators of cytotoxicity and contribute to understanding the mechanisms for each chemical. In combination with previously published reports, the similarity of results among cell lines may be explained by the origin of the cell lines rather than by the diversity of the methods and indicators employed.

Modulation of c-jun and c-fos transcription by UVB and UVA radiations in human dermal fibroblasts and KB cells.

We have previously demonstrated that the oxidizing component of ultraviolet-A (UVA) plays a central role in the activation of the nuclear oncogene and transcription factor, c-fos, in cultured human skin fibroblasts. We have now shown that expression of both c-jun and c-fos (AP-1) family of transcription factors is modulated by short and long wavelength solar ultraviolet (UV) radiation in human fibroblasts and human KB cells. UVA radiation activated c-jun and c-fos in both fibroblasts and KB cells, whereas ultraviolet-B (UVB) radiation activates such oncogenes only in KB cells. Moreover, decreasing the intracellular levels of reducing equivalents in human fibroblasts by glutathione (GSH) depletion lowered the UVA dose threshold for c-jun and c-fos activation several-fold and greatly amplified the UVA-mediated activation of such genes. A more modest effect was observed in GSH-depleted KB cells. In both GSH-depleted fibroblasts and KB cells, UVB radiation failed to amplify c-jun and c-fos activation indicating that the oxidative component of UVB plays a minor role in the modulation of such oncogene expression. These findings clearly indicate that both c-jun and c-fos are activated by the oxidizing component of UVA radiation in human fibroblasts and KB cells, while UVB-mediated modulation seems to be restricted to human epithelial cells and does not involve oxidizing intermediates.

Substance P Activates Coincident NF-AT- and NF-κB-Dependent Adhesion Molecule Gene Expression in Microvascular Endothelial Cells Through Intracellular Calcium Mobilization

AbstractUpon stimulation, cutaneous sensory nerves release neuropeptides such as substance P (SP), which modulate responses in the skin by activating a number of target cells via neurokinin receptors. We have demonstrated that SP preferentially binds to the NK-1R on human dermal microvascular cells, resulting in increased intracellular Ca2+ and induction of ICAM-1 and VCAM-1 expression. In the current studies, we identify specific elements in the regulatory regions of ICAM-1 and VCAM-1 genes as necessary and sufficient for SP-dependent transcriptional activation. SP treatment of human dermal microvascular endothelial cells leads to coincident activation and binding of the transcription factor NF-AT to the −191/−170 region of the ICAM-1 gene (a region bound by activated p65/p65 homodimers in response to TNF-α), and NF-κB (p65/p50) to tandem NF-κB binding sites at −76/−52 of the VCAM-1 gene. The SP-elicited intracellular Ca2+ signal was required for activation and subsequent binding of both NF-AT and NF-κB. The transacting factor induction by SP was specific, since a selective NK-1R antagonist blocked SP activation and subsequent NF-AT and NF-κB activation and binding. These data demonstrate coincident activation of NF-AT and NF-κB via SP-induced intracellular Ca2+ mobilization and indicate a crucial role for neuropeptides in modulating localized cutaneous inflammatory responses.

Histamine-induced Changes in the Actin Cytoskeleton of the Human Microvascular Endothelial Cell line HMEC-1

Increased permeability of the microvascular endothelium is a component of the inflammatory response. Inflammatory mediators such as histamine contribute to this permeability change. Modulation of cytoskeletal F-actin has been implicated as part of the cellular mechanism involved. Permeability changes occur predominantly at the microvascular level while the majority of current knowledge stems from research on cells from large vessels. We have therefore utilized an immortalized human dermal microvascular cell line, HMEC-1. Confluent monolayers were exposed to histamine (10 μ m, 100 μ m) for 1, 5, 10 or 15 minutes. F-Actin changes were detected by labelling with FITC-conjugated phalloidin. Histamine exposure resulted in the rounding of cells with the formation of intercellular gaps. The percentage of rounded cells and the number of gaps increased with exposure time. F-actin was redistributed from a peripheral band in control cultures to a perinuclear zone. Continual presence of the agonist was required for these phenotypic changes to occur. Removal of histamine caused reversal of these observations. Cells exposed to histamine for 1 minute needed 15 minutes to recover their normal morphology and F-actin distribution. These reversible effects suggest that F-actin redistribution maybe part of the microvascular cell response to histamine.

Angiostatin Diminishes Activation of the Mitogen-Activated Protein Kinases ERK-1 and ERK-2 in Human Dermal Microvascular Endothelial Cells

Angiostatin is an endogenous inhibitor of angiogenesis that was isolated from tumor-bearing mice. It has been established that angiostatin inhibits endothelial cell proliferation; however, the underlying mechanisms remain to be elucidated. Here we report that angiostatin reduces transiently the phosphorylation of the mitogen-activated protein kinases ERK-1 and ERK-2 in human dermal microvascular cells, but not in human vascular smooth muscle cells or human dermal fibroblasts. We demonstrate that angiostatin diminishes ERK activation by basic fibroblast growth factor and vascular endothelial growth factor. Dephosphorylation of ERK and other tyrosine-phosphorylated proteins was blocked by pretreatment of the cells with sodium meta-vanadate, an inhibitor of protein tyrosine phosphatases, indicating that angiostatin signaling may require the activity of a tyrosine phosphatase. Concentrations of angiostatin that inhibited ERK activation also inhibited basic fibroblast growth factor-stimulated collagen gel invasion by endothelial cells, but did not affect endothelial cell proliferation. We thus show that angiostatin inhibits primarily the invasion of endothelial cells and exerts minimal (if any) effects on their proliferation. Invasion is a process that involves proteolysis, adhesion and migration, all of which have been linked to ERK signaling.

Acute cytotoxicity testing with cultured human lung and dermal cells.

An extensive in vitro study with cultured cells was conducted to test the basal cytotoxicity theory. This theory suggests that most chemical injury, at least in vitro, is a manifestation of one or more insults to the basic cellular structures and functions common to mammalian cells. This accounts for the similarity of results in multilaboratory studies. Human fetal lung fibroblasts (HFL1), and human skin fibroblasts (WS1, Detroit551) were studied in culture to evaluate their potential to screen for cytotoxicity. Confluent monolayers were incubated in the absence or presence of increasing concentrations of test chemicals for 24 h, and the MTT assay was used to assess toxicity. Inhibitory concentrations were extrapolated from concentration-effect curves after linear regression analysis. Twenty-nine chemicals were tested with each cell line and the cytotoxicity data compared to rodent and human lethal concentrations. The data suggest that the experimental IC50 values are as accurate predictors of human toxicity as equivalent toxic blood concentrations derived from rodent LD50s. In addition, lung and skin fibroblasts revealed no significant differences among the three cell lines. The results support the conclusion that finite cell lines of human origin have the potential for screening chemicals for human toxicity. In combination with previously published reports, the data suggest that a basal cytotoxic phenomenon may explain the similarity of results among different human cell lines.

Phorbol-myristate-acetate, but not interleukin-1 beta or insulin-like growth factor-I, regulates protein kinase C isoenzymes in human dermal papilla cells.

The in vitro growth of human hair follicles is inhibited by interleukin (IL)-1 beta and phorbol esters, such as phorbol-myristate-acetate (PMA), but enhanced by insulin-like growth factor (IGF)-I. Although this process is only incompletely understood, the dermal papilla as a pivotal part of the hair follicle is almost certainly involved. Since protein kinase C (PKC) isoenzymes are activated by phorbol esters and are key enzymes in signalling pathways of several hormones, neurotransmitters, and growth factors, we addressed the question whether the action of the above-mentioned hair growth-modulating substances may affect PKC isoenzymes in cultured dermal papilla cells (DPC). By Western blot analysis, protein kinase C alpha, -epsilon, -gamma, -iota, -lambda, and the RACK1 receptor protein were detected in dermal papilla cell cultures, whereas the isoenzymes delta and mu were expressed only at low levels and protein kinase C-beta, -theta, and -zeta, were not present. After PMA stimulation, the PKC alpha, -epsilon, and -gamma were translocated from the cytosol to the membrane fraction and subsequently down-regulated. PKC iota was down-regulated but not translocated, and PKC lambda and RACK1 were not affected by PMA. Neither, IL-1 beta nor IGF had an effect on PKC or RACK1 expression. We conclude that cultured DPC express a distinct PKC isoenzyme pattern and that the PMA-induced growth arrest in cultivated hair follicles may be transmitted via protein kinases, whereas the effects of IL-1 beta or IGF may be transduced via other signal transduction pathways or other cell types.

A Novel Technique for Culture of Human Dermal Microvascular Endothelial Cells under either Serum-Free or Serum-Supplemented Conditions: Isolation by Panning and Stimulation with Vascular Endothelial Growth Factor

Several physiological and pathophysiological events involving vascular endothelium occur at the microvascular level. Studies on human microvasculature require homogenous primary cultures of microvascular endothelial cells. However, procedures available for isolating and culturing human dermal microvascular cells (HDMEC) result in significant contamination with fibroblasts. To eliminate contamination with fibroblasts or other cells, we developed a procedure to isolate HDMEC from neonatal human foreskin by panning the cells using EN4, an anti-endothelial cell monoclonal antibody. Panned cells uniformly expressed von Willebrand factor and CD36, confirming their microvascular endothelial characteristics, whereas cells cultured without panning showed a significant degree of contamination with fibroblasts. In the presence of vascular endothelial growth factor (VEGF), HDMEC could be cultured under serum-free conditions. VEGF stimulated the growth of HDMEC in a dose-dependent manner in serum-free medium or in media supplemented with either human serum or newborn calf serum. Since differences exist between large vessel endothelial cells and microvascular endothelial cells, we compared the response to VEGF stimulation of HDMEC with human umbilical vein endothelial cells (HUVEC). The dose response of the two cell types to VEGF was different. This effect of VEGF on endothelial cells may be mediated by the VEGF receptor kdr,since mRNA for kdrwas detected using RT–PCR in both HDMEC and HUVEC. The procedure described in this study will make possible the culture of highly enriched HDMEC without contamination with fibroblasts and facilitate studies with these cells under defined assay conditions in a serum-free environment.