Proliferation–differentiation relationships in the expression of heparin-binding epidermal growth factor-related factors and erbB receptors by normal and psoriatic human keratinocytes

The topological relationships between erbB receptors and ligands of the epidermal growth factor family were characterized by immunocytochemistry in normal and psoriatic epidermis and in proliferating and differentiating human keratinocytes in culture. Spatial colocalization of receptors and ligands was assessed by dual immunostaining. Expression of epidermal growth factor receptor (EGFr), erbB2, and erbB3, but not erbB4, was detected throughout the epidermis, although labeling for erbB2 and erbB3 was accentuated in the upper spinous layers, and EGFr was more strongly labeled in basal cells. Of the tested growth factors, heparin-binding epidermal growth factor (HB-EGF) was diffusely expressed throughout normal and psoriatic epidermis and sparsely colocalized with EGFr in all viable epidermal layers, with increased colocalization in psoriatic epidermis. In contrast, betacellulin and heregulin/neu differentiation factor (NDF) alpha were largely restricted in their distribution to the upper spinous and granular layers. Betacellulin was downregulated in psoriatic keratinocytes. Although heregulin/NDF-beta was undetectable in normal epidermis, it was upregulated in psoriasis. Betacellulin and heregulin/NDF-alpha strikingly colocalized with EGFr and erbB3 receptors in the granular layer and in a declining gradient from the granular zone to the basal layer, respectively. Similar patterns were observed in cultured keratinocytes under proliferative conditions and upon differentiation in high-calcium medium. These morphological data collectively suggest divergent functions for members of the growth factor family, and in particular, we propose that betacellulin and heregulin/NDF-alpha are involved in epidermal morphogenesis and/or in maintenance of the differentiated phenotype.     

Analysis of αv integrin protein expression in human eyelid and periorbital squamous cell carcinomas

Background: Alpha v integrins are receptors for many extracellular matrix (ECM) protein ligands, including latent transforming growth factor betas (TGFβs). Various studies in mice have shown that ablation of genes encoding αv integrin or TGFβ signaling pathway components leads to spontaneous squamous cell carcinomas (SCCs) in the conjunctiva and periocular skin. Here, we have analyzed patterns of αv integrin protein expression and TGFβ signaling in human eyelid and periorbital SCC samples. Methods: An anti‐αv integrin antibody was used to immunostain 19 eyelid and periorbital SCC samples. Additionally, tissue lysates from resected normal eyelid and SCC samples were analyzed by immunoblotting for αv integrin protein. Tumor sections were also immunostained with an antibody directed against Smad2, an intracellular signaling protein that is phosphorylated by TGFβ receptors. Results: Alpha v integrin protein was highly expressed in the invasive and less‐differentiated components of human SCCs. Lower levels of αv integrin protein were detected in more differentiated components of tumors, as well as in SCC in situ. Patterns of phosphorylated Smad2 immunoreactivity correlated with levels αv integrin expression. Conclusions: Alpha v integrin was expressed at robust levels in tumor cells representing less differentiated, more invasive components of SCC; by contrast, well‐differentiated cells as well as SCC in situ expressed low levels of αv integrin protein. Hsu A, Esmaeli B, Hayek B, Hossain MG, Shinder R, Lazar AJ, McCarty JH. Analysis of αv integrin protein expression in human eyelid and periorbital squamous cell carcinomas.     

Involvement of RAGE, MAPK and NF-κB pathways in AGEs-induced MMP-9 activation in HaCaT keratinocytes

Advanced glycation end products (AGEs) exert divergent effects on the pathogenesis of diabetes complications. Excessive expression of matrix metalloproteinases-9 (MMP-9) is deleterious to the cutaneous wound-healing process in the context of diabetes. However, the effect of AGEs on MMP-9 induction in skin cells and the exact molecular mechanisms involved are still poorly understood. In this study, we investigated the effect of AGEs on the production of MMP-9 in HaCaT keratinocytes and characterized the signal transduction pathways activated by AGEs that are involved in MMP-9 regulation. We showed that AGE-BSA increased MMP-9 expression in HaCaT cells at both the protein and mRNA levels. The stimulatory effect of AGE-BSA on MMP-9 was attenuated by inhibitors of extracellular-signal-regulated kinase (ERK1/2, U0126), p38 mitogen-activated protein kinase (MAPK, SB203580) and NF-κB, but not c-Jun N-terminal kinase. Furthermore, receptor for advanced glycation end products (RAGE) was expressed in keratinocytes, and incubation with AGE-BSA resulted in a significant upregulation of RAGE expression in a dose-dependent manner. Silencing of the RAGE gene prevented AGE-BSA-induced MMP-9 activation and the phosphorylation of ERK1/2 and p38 MAPK. We also observed the involvement of NF-κB in AGE-BSA-induced MMP-9 activation, which was not blocked by U0126 and SB203580. These results suggest that AGEs may play an important role in the impairment of diabetic wound healing by upregulating MMP-9 expression in keratinocytes via the RAGE, ERK1/2 and p38 MAPK pathways; activation of NF-κB is also involved in this process. These pathways may represent potential targets for drug interventions to improve diabetic wound healing, a process in which MMP-9 plays a critical role.     

Nicotine and biochanin A, but not cigarette smoke, induce anti-inflammatory effects on keratinocytes and endothelial cells in patients with Behçet's disease

During periods of smoking, patients with Beh?et's disease have less oral aphthae than in abstinence. To elucidate this observation, human keratinocytes and dermal microvascular endothelial cells (HMEC-1) were incubated with serum of 20 patients with Beh?et's disease and 20 healthy controls for 4 hours. Maximum non-toxic concentrations were determined and the cells were further treated with 6 microM nicotine, 3.3% cigarette smoke extract (CES), 100 microM biochanin A, and 6.25/12.5 microM pyrrolidine dithiocarbamate alone and in combinations for 24 hours. Serum IL-8 levels of patients were significantly lower than those of controls. However, after 4 hours incubation with patients' sera, IL-8 release by both cell types was markedly increased when compared with the corresponding serum levels. The levels of IL-6 and vascular endothelial growth factor (VEGF) release were after 4 hours similar with the corresponding levels in serum. IL-1 was not detected. Nicotine significantly decreased IL-8 and -6 release by HMEC-1 maintained in both patients' and controls' sera, but only IL-6 release by keratinocytes maintained in patients' sera. VEGF release by both cells was markedly increased after nicotine treatment in either serum. CES significantly decreased IL-8 release and increased production of VEGF in keratinocytes maintained in patients' serum. The phytoestrogen biochanin A alone and in combination with nicotine further decreased the secretion of IL-8, -6, and VEGF in all experimental settings. Our data support a specific anti-inflammatory effect of nicotine on keratinocytes and endothelial cells maintained in the serum of patients with Beh?et's disease. Moreover, biochanin A is likely to exhibit similar and even more profound results than nicotine.     

Effects of tacrolimus on the expression of nuclear factor-κB and glucocorticoid receptor by HaCaT cells in vitro

Objective To investigate the effect of tacrolimus on the expression of nuclear factor-κB (NF-κB) in HaCaT cells stimulated by tumor necrosis factor-α(TNF-α),and on the expression of glucocorticoid receptor (GR)α and β in untreated HaCaT cells in vitro.Methods Cultured Ha CaT cells were treated with TNF-α(10μg/L) only,combination of TNF-α(10μg/L) and various concentrations (10-8mol/L, 10-7mol/L,10-6moL/L) of tacrolimus or tacrolimus of different concentrations only.After additional 12-,24-, 36- or 48-hour cnlture, Westem blot and immunofluorescenee-confocal laser scanning microscopy were used to detect the expressions of NF-κB,GRα and GRβ in HaCaT cells.Those untreated HaCaT cells served as the control.Results The relative protein expression level of NF-κB was increased in HaCaT cells after treatment with TNF-α for 24 and 48 hours zompared with untreated ceils (0.73±0.0316 and 0.8925±0.0171 vs 0.4988±0.03506,both P<0.05);however,the increase in NF-κB expression was inhibited by the combination treatment with tacrolimus,and the relative expression level of NF-κB protein was 0.6825±0.0263.0.6200±0.0163 and 0.5575±0.0299 in HaCaT cells treated with TNF-α plus tacrolimus of 10-8mol/L 10-7mol/L and 10-6mol/L,respectively;the difference was significant etween TNF-α-treated cells and those dealt with the combination of NF-α and tacrolimus of 10-7 or 10-6 mol/L (both P<0.05).No significant difference was observed in the expression of NF-κB by HaCaT cells between different time oints treated with tacrolimus of 10-8,10-7 or 10-6 mol/L.Also,there was no zignificant difference in the expression of GRα or GRβ between untreated HaCaT cells and those treated with tacrolimus of 10-8, 10-7 or 10-6 mol/L at any time point.Conclusions Tacrolimus ould inhibit the expression of NF-κB by TNF-α-stimulated HaCaT cells,but does not affect the expression of GRα or GRβ,in untreated HaCaT cells.     

Effects of tacrolimus on the expression of nuclear factor-κB and glucocorticoid receptor by HaCaT cells in vitro

Objective To investigate the effect of tacrolimus on the expression of nuclear factor-κB (NF-κB) in HaCaT cells stimulated by tumor necrosis factor-α(TNF-α),and on the expression of glucocorticoid receptor (GR)α and β in untreated HaCaT cells in vitro.Methods Cultured Ha CaT cells were treated with TNF-α(10μg/L) only,combination of TNF-α(10μg/L) and various concentrations (10-8mol/L, 10-7mol/L,10-6moL/L) of tacrolimus or tacrolimus of different concentrations only.After additional 12-,24-, 36- or 48-hour cnlture, Westem blot and immunofluorescenee-confocal laser scanning microscopy were used to detect the expressions of NF-κB,GRα and GRβ in HaCaT cells.Those untreated HaCaT cells served as the control.Results The relative protein expression level of NF-κB was increased in HaCaT cells after treatment with TNF-α for 24 and 48 hours zompared with untreated ceils (0.73±0.0316 and 0.8925±0.0171 vs 0.4988±0.03506,both P<0.05);however,the increase in NF-κB expression was inhibited by the combination treatment with tacrolimus,and the relative expression level of NF-κB protein was 0.6825±0.0263.0.6200±0.0163 and 0.5575±0.0299 in HaCaT cells treated with TNF-α plus tacrolimus of 10-8mol/L 10-7mol/L and 10-6mol/L,respectively;the difference was significant etween TNF-α-treated cells and those dealt with the combination of NF-α and tacrolimus of 10-7 or 10-6 mol/L (both P<0.05).No significant difference was observed in the expression of NF-κB by HaCaT cells between different time oints treated with tacrolimus of 10-8,10-7 or 10-6 mol/L.Also,there was no zignificant difference in the expression of GRα or GRβ between untreated HaCaT cells and those treated with tacrolimus of 10-8, 10-7 or 10-6 mol/L at any time point.Conclusions Tacrolimus ould inhibit the expression of NF-κB by TNF-α-stimulated HaCaT cells,but does not affect the expression of GRα or GRβ,in untreated HaCaT cells.     

Bcl-2 transfected HaCaT keratinocytes resist apoptotic signals of ceramides, tumor necrosis factor α and 1α,25-dihydroxyvitamin D3

Abstract During the last few years increasing evidence has shown that sphingolipid metabolites are highly bioactive compounds that play important roles in cellular regulation. The induction of ceramide signalling in primary human keratinocytes and HaCaT keratinocytes has recently been demonstrated using 1·,25-dihydroxyvitamin D₃. The data obtained indicate that approximately one-third of the proapoptotic effect of 1·,25-dihydroxyvitamin D₃ is mediated by an intracellular ceramide increase induced via tumor necrosis factor · expression and autocrine stimulation of sphingomyelin hydrolysis. In the present study the role of bcl-2 in this process was investigated. HaCaT keratinocytes were transfected with bcl-2 and the effects of C₂-ceramide, tumor necrosis factor · and 1·,25-dihydroxyvitamin D₃ on HaCaT keratinocytes stably overexpressing bcl-2 were determined. Apoptosis was measured by detection of soluble DNA-histone complexes using the ELISA technique. In situ analysis of apoptotic cells was also carried out by detecting phosphatidylserine flip using the annexin V method and by detecting DNA fragmentation using the TUNEL assay. The results obtained showed that apoptosis induced by C₂-ceramide, tumor necrosis factor · or 1·,25-dihydroxyvitamin D₃ occurred in a vector-transfected clone but not in a bcl-2-transfected HaCaT clone. This indicates the important role of bcl-2 in the regulation of ceramide-mediated signalling pathways in human keratinocytes and supports the involvement of ceramide as a signalling molecule in 1α,25-dihydroxyvitamin D₃-induced biological responses. Received: 4 January 2000 / Revised: 26 May 2000 / Accepted: 8 June 2000     

Expression of the collagen VI α5 and α6 chains in normal human skin and in skin of patients with collagen VI-related myopathies

Collagen VI is an extracellular matrix protein with critical roles in maintaining muscle and skin integrity and function. Skin abnormalities, including predisposition to keratosis pilaris and abnormal scarring, were described in Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) patients carrying mutations in COL6A1, COL6A2, and COL6A3 genes, whereas COL6A5, previously designated as COL29A1, was linked to atopic dermatitis. To gain insight into the function of the newly identified collagen VI α5 and α6 chains in human skin, we studied their expression and localization in normal subjects and in genetically characterized UCMD and BM patients. We found that localization of α5, and to a lesser extent α6, is restricted to the papillary dermis, where the protein mainly colocalizes with collagen fibrils. In addition, both chains were found around blood vessels. In UCMD patients with COL6A1 or COL6A2 mutations, immunolabeling for α5 and α6 was often altered, whereas in a UCMD and in a BM patient, each with a COL6A3 mutation, expression of α5 and α6 was apparently unaffected, suggesting that these chains may substitute for α3, forming α1α2α5 or α1α2α6 heterotrimers.     

p38δ mitogen-activated protein kinase regulates the expression of tight junction protein ZO-1 in differentiating human epidermal keratinocytes

Increasing evidence has recognized tight junctions (TJs) as the lower epidermal inside-out diffusion barrier located in granular cell layers of the epidermis. However, little is known about the regulation of TJ components in epidermis. p38 pathway is one of the mitogen-activated protein kinase pathways, which controls cell growth, differentiation, and apoptosis. We have investigated the role of p38 signaling pathway in the regulation of selected desmosomal, adherens and TJ components in human primary keratinocytes during Ca²⁺-induced differentiation, as well as in cultured squamous cell carcinoma cell lines. p38 signaling pathway was inhibited in cultured keratinocytes and cutaneous squamous cell carcinoma cells using recombinant adenoviruses, small inhibitory RNAs (siRNA) and chemical inhibitors. Expression of intercellular junction proteins was investigated using Western analysis and indirect immunofluorescence (IIF). The results showed that inhibition of p38δ function by siRNA or adenovirally delivered dominant negative mutant led to markedly decreased levels of Zonula occludens-1 (ZO-1) protein in keratinocytes, while the expression of other junctional proteins studied was not altered. Immunolocalization of ZO-1 revealed that intercellular junction areas were depleted from ZO-1. Inhibition of ZO-1 by siRNA silencing did not however result in an altered expression or subcellular localization of other TJ components studied. The expression of ZO-1 in carcinoma cells was also regulated by p38. The results indicate that ZO-1 is regulated by p38δ while the other junction proteins studied are not. Since ZO-1 is an integral component of functional TJs, various pathological processes affecting signaling via p38δ may also interfere with epithelial maturation and the formation and function of TJs.     

Influence of an anti-integrin α6 monoclonal antibody on the in vitro infection of human HaCaT keratinocytes with human papillomavirus (HPV) 6/11 virus particles

Objective To investigate the influence of an anti-integrin α6 monoclonal antibody (GoH3) on the in vitro infection of a human keratinocyte cell line HaCaT with HPV6/11 virus particles (VP). Methods HaCaT cells were infected in vitro with 4 different concentrations of HPV6/11 VP alone, HPV6/11 VP of 106 copies/ml after incubation with 6 different dilutions of GoH3, or 8 clinical isolates of HPV6/11 VP of 106 copies/ml before or after the incubation with 1∶ 100 dilution of GoH3. After additional culture, the infected HaCaT cells were collected and fluorescence quantitative (FQ)-PCR was performed to detect the HPV DNA load in cells. The inhibition rate of CoH3 on the infection was calculated. Results The viral load was different among the HaCaT cells infected with different concentrations of HPV6/11 VP (P < 0.01). The inhibition rate on the infection positively correlated with the concentration of CoH3 when the dilution was more than 1∶ 100; however, when the dilution was less than 1∶ 100, the increase in CoH3 concentration had no influence on the inhibition rate. The average viral load in HaCaT cells infected with clinical isolates of HPV6/11 VP was (5.81 ± 2.51) × 104 copies/ml in the absence of GoH3, (3.02 ± 1.21) × 104 copies/ml with the presence of CoH3, and the average inhibition rate of GoH3 was (46.9 ± 4.7)%. Conclusions GoH3 could partially suppress the adhesion of HPV6/11 VP to HaCaT cells, hinting that integrin a6 is an important HPV6/11 VP receptor on host cells.     

Influence of an anti-integrin α6 monoclonal antibody on the in vitro infection of human HaCaT keratinocytes with human papillomavirus (HPV) 6/11 virus particles

Objective To investigate the influence of an anti-integrin α6 monoclonal antibody (GoH3) on the in vitro infection of a human keratinocyte cell line HaCaT with HPV6/11 virus particles (VP). Methods HaCaT cells were infected in vitro with 4 different concentrations of HPV6/11 VP alone, HPV6/11 VP of 106 copies/ml after incubation with 6 different dilutions of GoH3, or 8 clinical isolates of HPV6/11 VP of 106 copies/ml before or after the incubation with 1∶ 100 dilution of GoH3. After additional culture, the infected HaCaT cells were collected and fluorescence quantitative (FQ)-PCR was performed to detect the HPV DNA load in cells. The inhibition rate of CoH3 on the infection was calculated. Results The viral load was different among the HaCaT cells infected with different concentrations of HPV6/11 VP (P < 0.01). The inhibition rate on the infection positively correlated with the concentration of CoH3 when the dilution was more than 1∶ 100; however, when the dilution was less than 1∶ 100, the increase in CoH3 concentration had no influence on the inhibition rate. The average viral load in HaCaT cells infected with clinical isolates of HPV6/11 VP was (5.81 ± 2.51) × 104 copies/ml in the absence of GoH3, (3.02 ± 1.21) × 104 copies/ml with the presence of CoH3, and the average inhibition rate of GoH3 was (46.9 ± 4.7)%. Conclusions GoH3 could partially suppress the adhesion of HPV6/11 VP to HaCaT cells, hinting that integrin a6 is an important HPV6/11 VP receptor on host cells.     

Influence of an anti-integrin α6 monoclonal antibody on the in vitro infection of human HaCaT keratinocytes with human papillomavirus (HPV) 6/11 virus particles

Objective To investigate the influence of an anti-integrin α6 monoclonal antibody (GoH3) on the in vitro infection of a human keratinocyte cell line HaCaT with HPV6/11 virus particles (VP). Methods HaCaT cells were infected in vitro with 4 different concentrations of HPV6/11 VP alone, HPV6/11 VP of 106 copies/ml after incubation with 6 different dilutions of GoH3, or 8 clinical isolates of HPV6/11 VP of 106 copies/ml before or after the incubation with 1∶ 100 dilution of GoH3. After additional culture, the infected HaCaT cells were collected and fluorescence quantitative (FQ)-PCR was performed to detect the HPV DNA load in cells. The inhibition rate of CoH3 on the infection was calculated. Results The viral load was different among the HaCaT cells infected with different concentrations of HPV6/11 VP (P < 0.01). The inhibition rate on the infection positively correlated with the concentration of CoH3 when the dilution was more than 1∶ 100; however, when the dilution was less than 1∶ 100, the increase in CoH3 concentration had no influence on the inhibition rate. The average viral load in HaCaT cells infected with clinical isolates of HPV6/11 VP was (5.81 ± 2.51) × 104 copies/ml in the absence of GoH3, (3.02 ± 1.21) × 104 copies/ml with the presence of CoH3, and the average inhibition rate of GoH3 was (46.9 ± 4.7)%. Conclusions GoH3 could partially suppress the adhesion of HPV6/11 VP to HaCaT cells, hinting that integrin a6 is an important HPV6/11 VP receptor on host cells.     

Effect of Shuxuetong injection on the expression of MMP-2 and α-SMA in hypertrophic scars of rab⁃ bit ear

Objective: To determine the effect of Shuxuetong injection on the expression s of matrix metal-loproteinase 2 (MMP-2) and α-smooth muscle actin (α-SMA) in hypertrophic scar of rabbit ear. Methods: Nine New Zealand white rabbits were selected randomly. Firstly we established a hyperplastic scar model of rabbit ears. When the wounds were reepithelialized after 30 days, the nine rabbits were randomly divided into three groups: blank control group, triamcinolone acetonide injection group and Shuxuetong injection group (3 rabbits in each group). After 20 days, the thickness of scar was measured and the scar hyperplasia index was calculated. The histological structure and the collagen fiber expression were observed by hematoxylin-eosin (HE) and VG staining. The levels of MMP-2 or α-SMA mRNA and protein levels were detected by qRT-PCR and Western Blot. Results: The scar thickness, scar hyperplasia index, the mRNA and protein level of MMP-2 and α-SMA were 36.67±1.74, 1.19±0.07, 0.28±0.04, 0.53±0.06, 1.40±0.34 and 0.56±0.06, respectively, in the Shuxuetong group, were 35.33±3.51, 1.25±0.15, 0.18±0.01, 0.39±0.03, 1.03±0.1 and 0.50±0.03, in the triamcinolone acetonide group, and were 85.00±7.38, 2.77±0.37, 1.01±0.07, 0.83±0.06, 4.43±0.47 and 0.81±0.05 in the blank control group. HE staining and VG staining showed that the fibroblasts and collagen fibers in the triamcinolone acetonide group and Shuxuetong group were less than that in the blank control.group. Conclusion: Shuxuetong injection can inhibit the proliferation of scar tissue by decreasing the expression of MMP-2 and α-SMA. © 2019 Shandong Yinbao Technology Co. Ltd. All rights reserved.     

Corticosteroids induce proliferation but do not influence TNF- or IL-1Β-induced ICAM-1 expression of human dermal microvascular endothelial cells in vitro

The effects of hydrocortisone, dexamethasone, betamethasone 17-valerate and clobetasol propionate at concentrations of 10^–5–10^–12 M on the proliferation of human dermal microvascular endothelial cells (HDMEC) were studied in vitro. In addition, confluent HDMEC were treated with TNF (1000 U/ml) or IL-1 (1000 U/ml) alone or in combination with the corticosteroids (10^–5 M, 10^–6 M) for 24 h, and cytokine-induced expression of intercellular adhesion molecule-1 (ICAM-1) was assessed by immunocytochemistry. Controls were treated either with growth medium or with the corticosteroids alone. All tested corticosteroids stimulated HDMEC growth after 4 and 6 days of treatment in a dose-dependent manner, as assessed by ³H-thymidine incorporation and the 4-methyl-umbelliferyl heptanoate (MUH) assay. The minimal effective concentration was 10^–9 M for hydrocortisone, 10^–10 M for dexamethasone and betamethasone, and 10^–12 M for clobetasol. In untreated and in corticosteroid-treated cultures, less than 5% of the cells expressed ICAM-1. TNF and IL-1 were strong inducers of ICAM-1 expression on 74% and 82% of the cells, respectively. None of the tested corticosteroids significantly influenced cytokine-induced ICAM-1 expression, suggesting that the anti-inflammatory effects of corticosteroids are not related to ICAM-1 modulation on HDMEC.