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Biomedical subjects

J Gille

Publications and source records attributed to J Gille.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ultraviolet-A-induced transactivation of the vascular endothelial growth factor gene in HaCaT keratinocytes is conveyed by activator protein-2 transcription factor.

Ultraviolet-A radiation represents a significant proportion of the ultraviolet solar spectrum that was recently shown to affect gene expression of epidermal keratinocytes by molecular mechanisms distinct from ultraviolet-B radiation. As ultraviolet-A either alone or in combination with ultraviolet-B may contribute to photocarcinogenesis, we aimed to explore the biologic effects of ultraviolet-A radiation on vascular endothelial growth factor gene expression by the immortalized keratinocyte cell line HaCaT. As keratinocyte-derived vascular endothelial growth factor not only provides the major cutaneous angiogenic activity but may also augment the malignant phenotype of tumor cells, we studied the molecular mechanisms of ultraviolet-A-induced vascular endothelial growth factor expression in HaCaT cells, serving as a transformed preneoplastic epithelial cell line. Whereas ultraviolet-B-mediated vascular endothelial growth factor expression has been previously indicated to be conveyed by indirect mechanisms, ultraviolet-A rapidly induced vascular endothelial growth factor mRNA expression in a fashion comparable to that seen with the transforming growth factor alpha, representing a direct and potent activator of vascular endothelial growth factor gene transcription. Ultraviolet-A was found to readily induce vascular endothelial growth factor promoter-based reporter gene constructs through a consensus element for activator protein-2 transcription factor. The critical role of activator protein-2 was substantiated by demonstration of ultraviolet-A-induced activator-protein-2-dependent nuclear DNA binding activity to this site, and by inhibition of ultraviolet-A-mediated vascular endothelial growth factor gene transcription through insertion of a critical mutation within the activator protein-2 sequence. Together, our data further elucidate photobiologic aspects of ultraviolet-A-induced gene expression by characterizing mechanisms of vascular endothelial growth factor upregulation at the molecular level. In addition, our experiments support the concept of a more general importance of activator protein-2 in ultra- violet-A-mediated responses by keratinocytes or keratinocyte-derived cell lines.

Base Pairing↗
PubMed1998

Interferon enhances tumor necrosis factor-induced vascular cell adhesion molecule 1 (CD106) expression in human endothelial cells by an interferon-related factor 1-dependent pathway.

Tumor necrosis factor (TNF) and interleukin 1 are known to initiate endothelial vascular cell adhesion molecule (VCAM)-1 transcription primarily by activating nuclear factor (NF)-kappaB, which translocates to the nucleus. In addition to two NF-kappaB elements found within the minimal cytokine-inducible VCAM-1 promoter, an interferon-related factor (IRF) element (IRF-1) has been identified close to the transcription initiation site, suggesting that cytokines that induce IRF-1 might affect VCAM-1 expression levels. We therefore investigated the effects of interferons (IFNs), which strongly induce IRF-1, on VCAM-1 transcription and expression. We show that IFN-alpha and -gamma enhance TNF-induced VCAM-1 mRNA transcription and protein expression in human endothelial cells. IFN enhancement of TNF-induced expression is also seen using chloramphenicol acetyl transferase reporter genes linked to the minimal cytokine inducible VCAM-1 promoter. Nuclear IRF-1 is the molecular basis of IFN enhancement, because (a) IFN plus TNF-treated cells displayed increased nuclear IRF-1 levels and increased IRF-1 binding to the VCAM-1 promoter, compared with cells treated with TNF alone; (b) kinetics of nuclear IRF-1 levels correlated with VCAM-1 mRNA levels; (c) transfection with an IRF-1 construct substituted for IFN treatment; and (d) transfection with an expression construct encoding IRF-2, a competitive inhibitor of IRF-1, reduced TNF-induced VCAM-1 expression. Our experiments show that IFN amplifies TNF-induced VCAM-1 expression at the transcriptional level by an IRF-1-dependent pathway.

Cell Compartmentation↗
PubMed1998

Hepatocyte growth factor/scatter factor (HGF/SF) induces vascular permeability factor (VPF/VEGF) expression by cultured keratinocytes.

Skin expression of the endothelial cell-specific vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) as an outstanding mediator of physiologic and pathologic angiogenesis has been previously demonstrated to be subject to regulation by distinct stimuli. We explored whether the multifunctional hepatocyte growth factor/scatter factor (HGF/SF) may mediate its angiogenic properties in part through paracrine induction of cutaneous VPF/VEGF synthesis. In these studies, we demonstrate that HGF/SF functions as a potent inducer of VPF/VEGF expression by human epidermal keratinocytes and by different epithelial-derived cells in vitro. VPF/VEGF mRNA and protein expression are regulated by HGF/SF in both a concentration- and a time-dependent fashion. Examination of mRNA half-lives does not reveal an increase in VPF/VEGF mRNA stability after HGF/SF stimulation. Thus, HGF/SF-induced VPF/VEGF mRNA expression appears to be largely dependent on enhanced gene transcription. In analyses of transiently transfected 5'-deletional reporter gene constructs, we identified a GC-rich VPF/VEGF promoter element that conveys transcriptional activation in response to HGF/SF. This sequence, located between nucleotides -88 and -70, is critical for both constitutive and HGF/SF-induced transcriptional activity. Together, our observations support a model in which HGF/SF mediates angiogenic properties in part through paracrine induction of VPF/VEGF synthesis by keratinocytes. In addition to cutaneous inflammation and wound healing, our findings have potential significance for vascular hyperpermeability and angiogenesis in tumor growth.

5' Untranslated Regions↗
PubMed1997

Transforming growth factor-alpha-induced transcriptional activation of the vascular permeability factor (VPF/VEGF) gene requires AP-2-dependent DNA binding and transactivation.

The endothelial cell-specific mitogen vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) represents a central regulator of cutaneous angiogenesis. Increased VPF/VEGF expression has recently been reported in psoriatic skin and healing wounds, both conditions in which transforming growth factor-alpha (TGF alpha) and its ligand, the epidermal growth factor receptor, are markedly up-regulated. Since TGF alpha strongly induces VPF/VEGF synthesis in keratinocytes, TGF alpha-mediated VPF/VEGF expression is likely to play a significant role in the initiation and maintenance of increased vascular hyperpermeability and hyperproliferation in skin biology. The objectives of the present studies were to determine the molecular mechanisms responsible for TGF alpha-induced transcriptional activation of the VPF/VEGF gene. We have identified a GC-rich TGF alpha-responsive region between -88 bp and -65 bp of the VPF/VEGF promoter that is necessary for constitutive and TGF alpha-inducible transcriptional activation. In electrophoretic mobility shift assays, this region binds Sp1-dependent protein complexes constitutively and an additional TGF alpha-inducible protein complex that is distinct from Sp1 protein. Both AP-2 and Egr-1 transcription factors were detected as components of the TGF alpha-inducible protein complex in supershift EMSA studies. In co-transfection studies, an AP-2 but not an Egr-1 expression vector activated VPF/VEGF transcription, thus indicating that AP-2 protein is functionally important in TGF alpha-induced VPF/VEGF gene expression. By clarifying regulatory mechanisms that are critical for angiogenic processes in the skin, these studies may form the basis for new therapeutic strategies to modulate VPF/VEGF expression in cutaneous inflammation and wound healing.

Base Sequence↗
PubMed1997

Retinoic acid inhibits the regulated expression of vascular cell adhesion molecule-1 by cultured dermal microvascular endothelial cells.

The regulated expression of cell adhesion molecules (CAM) on endothelial cells is central to the pathogenesis of various inflammatory processes. Retinoic acid and synthetic derivatives have been demonstrated to exert antiinflammatory effects in cutaneous diseases. To determine modes of retinoid action in the modulation of inflammatory responses, we explored effects of all-trans-retinoic acid (t-RA) on the TNFalpha-induced expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin in cultured human dermal microvascular endothelial cells. Pretreatment with t-RA specifically prevented TNFalpha-induced VCAM-1 expression, but not ICAM-1 and E-selectin induction. t-RA significantly reduced VCAM-1-dependent T cell binding to TNFalpha-treated human dermal microvascular endothelial cells as well. This differential modulation of TNFalpha-induced CAM expression by t-RA was reflected at steady state mRNA levels and in nuclear run-on studies. In transcriptional activation studies, the TNFalpha-mediated activation of the human VCAM-1 promoter was inhibited after t-RA treatment, while the ICAM-1 promoter activation was unaffected, indicating that the selective inhibition of CAM expression is regulated in part at the level of gene transcription. Furthermore, the transcriptional inhibition by t-RA appears to be mediated by its effects upon the activation of NF-kappaB-dependent complex formation. Analysis of protein-DNA binding assays revealed marked inhibition of specific NF-kappaB-dependent binding to the tandem NF-KB sites of the VCAM-1 promoter, but not to the functional NF-kappaB motif of the ICAM-1 promoter. The specific inhibition of cytokine-mediated VCAM-1 gene expression in vitro may provide a potential basis by which retinoids exert their biological effects at sites of inflammation in vivo.

Blotting, Northern↗
PubMed1996

Integrins: role in cell adhesion and communication.

Adhesive interactions are crucial for the integrity and function of all cells and tissues. As one of the major families of cell adhesion receptors, the integrins have been the focus of scientific interest for more than a decade. The resulting studies have tremendously enhanced the understanding of integrin-mediated adhesive interactions and have unveiled novel integrin functions in the cytoskeletal organization of microfilaments and in the activation of diverse signaling pathways. These functions are critically involved in the regulation of multiple processes, such as tissue development, inflammation, tumor cell growth and metastasis, and programmed cell death. The global view of integrin receptor biology has radically changed and has become much more subtle and elaborate. The enormous complexity of integrin function is determined by the heterodimeric formation of more than 20 functional integrin receptors, the cell type-specific distribution, the receptor activation state, the presence of different activation and deactivation signals, and the subsequent employment of distinct cytoskeletal and signaling complexes within a more dimensional network of time and space. This article summarizes the structural and functional properties of the integrin receptors and emphasizes some of the major achievements made in the past to enhance the understanding of integrin biology.

Animals↗
PubMed1996

Differential regulation of vascular cell adhesion molecule-1 gene transcription by tumor necrosis factor alpha and interleukin-1 alpha in dermal microvascular endothelial cells.

As part of the inflammatory response, the localization of leukocytes depends to an important degree on cytokine-induced expression of vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells (EC). We have previously shown that VCAM-1 expression is induced on human umbilical vein EC (HUVEC) by both tumor necrosis factor alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha), whereas on human dermal microvascular EC (HDMEC) only TNF alpha results in VCAM-1 expression. To explore molecular mechanisms responsible for these contrasting patterns of VCAM-1 induction in HUVEC versus HDMEC, we performed transcriptional activation studies with VCAM-1-based reporter constructs and in vitro binding assays using two adjacent NF-kappa B binding sequences of the VCAM-1 promoter as a DNA probe. Previous studies have established that these NF-kappa B motifs are required for cytokine-induced VCAM-1 transcription, and may further mediate cell-specific VCAM-1 gene activation by cytokines. The findings reported here demonstrate a significant HDMEC-specific attenuation of VCAM-1 gene transcription in response to IL-1 alpha, but not TNF alpha. An upstream VCAM-1 gene regulatory region distinct from the NF-kappa B sites appears to function as an IL-1 alpha-mediated transcriptional repressor within HDMEC. This repressor region conveys IL-1 alpha-dependent, but not TNF alpha-dependent, inhibition of transcription driven by a heterologous cytokine response element and promoter.

Base Sequence↗
PubMed1994

A factor in human plasma permits persistent expression of E-selectin by human endothelial cells.

E-selectin is an inducible endothelial cell adhesion protein that is a critical element in the binding of leukocytes to activated endothelial cells. It is induced by a variety of pro-inflammatory soluble substances including interleukin-1 (IL-1), tumor necrosis factor (TNF), or bacterial lipopolysaccharide (LPS). In vitro studies of a large vessel endothelial cells demonstrate that stimulation with TNF or IL-1 leads to a rapid, but transient, induction of E-selectin expression that disappears within 24 hours. However, in vivo studies have shown that microvascular endothelial cells persistently express E-selectin in chronic inflammatory states, particularly in the skin where it serves as a homing receptor for memory T cells. Stimulation of dermal-derived microvascular endothelial cells (HDMECs) with single doses of IL-1 alpha, TNF alpha, or LPS resulted in transient but slightly more persistent expression of E-selectin than seen after stimulation of large vessel derived umbilical vein endothelial cells (HUVECs). However, stimulation of either HDMECs or HUVECs with repetitive doses of IL-1 alpha, TNF alpha, or LPS in the presence of human serum or plasma resulted in persistent E-selectin expression in vitro. The persistent E-selectin cell surface expression was associated with persistent E-selectin mRNA expression and correlated with E-selectin-mediated HL-60 binding to endothelial cell monolayers. The effect of human plasma or serum was dose dependent, and fractionation of human plasma by gel filtration demonstrated that the E-selectin persistence activity resolved into high and low molecular peaks. These data demonstrate that human endothelial cells are capable of persistent E-selectin expression in vitro and that factors in human serum or plasma are critical in preventing cytokine refractoriness and loss of E-selectin expression. This study provides a basis to resolve the apparent discrepancies between previous in vivo and in vitro dynamics of E-selectin expression.

Blotting, Northern↗
PubMed1991

Flow-cytometric analysis of the DNA-content in paraffin-embedded tissue from colorectal carcinomas and its prognostic significance.

The nuclear DNA content of 163 colorectal carcinomas was determined by flow-cytometry (FCM) on formalin-fixed, paraffin-embedded tissue. DNA-aneuploidy was found in 97 cases (59.5%), in which no statistically significant correlations with sex, mean age, tumour stage (Dukes and pTNM) and tumour grade were noted. The frequency of aneuploidy was significantly higher in patients less than 70 years of age (p less than 0.01) and in tumours localized in the left colon and rectum (p less than 0.002), irrespective of their stage. The tumours in which different areas could be analysed (n = 80) showed a heterogeneous DNA-ploidy pattern in 18%. Comparison of the DNA content in primary tumours and in lymph node metastases (n = 49) showed a difference in DNA-ploidy in 38% of the DNA-aneuploid tumours, but in only 6% of the DNA-diploid carcinomas (p less than 0.02). DNA-aneuploid carcinomas tended to show a higher rate of local recurrence and were associated with an unfavourable prognosis (p = 0.04) in those patients in which complete resection of their tumours was possible (n = 72). The significantly higher mortality of patients with DNA-aneuploid carcinomas of stage pT3, as well as those with Dukes stage A and B tumours indicates that DNA-aneuploidy may be a stage-independent additional risk factor in colorectal cancer.

Aged↗
PubMed1990

[Retrospective flow-cytometric analysis of the DNA content in colorectal carcinomas and the test of the prognostic significance of DNA ploidy].

The nuclear DNA content of 163 colorectal carcinomas was determined by flow-cytometry (FCM) on formalin-fixed and paraffin-embedded tissue. DNA-aneuploidy was found in 97 cases (59.5%), without correlation to sex, mean age, tumor-stage (DUKES and pTNM) and grading. The frequency of aneuploidy was statistically significantly higher in patients younger than 70 years of age (p less than 0.01) and in tumors localized in the left colon and rectum (p less than 0.002). The tumors in which different areas could be analyzed (n = 80) showed a heterogeneous DNA-ploidy pattern in 18%. The comparison of DNA-content in primaries and in lymph-node metastases (n = 49) resulted in a difference of DNA-ploidy in 38% of the DNA-aneuploid tumors, but only in 6% of the DNA-diploid carcinomas (p less than 0.02). Carcinomas with DNA-aneuploidy showed a trend to a higher rate of loco-regional recurrences, a higher S-phase fraction (13.5% +/- 5.9 vs. 8.1 +/- 7.0), and proved to be associated with a poorer prognosis (p = 0.04). The statistically significantly higher mortality of patients with DNA-aneuploid carcinomas in DUKES A and B stages indicates that DNA-aneuploidy could perhaps be regarded as a stage-independent additional risk factor.

Aged↗
PubMed1987

Pregnancy following induction of ovulation with pure FSH after suppression of endogenous gonadotropins with subcutaneous buserelin.

Ovarian stimulation in patients with disorders of ovulation or an inadequate luteal phase using human menopausal gonadotropins (hMG) gives a low pregnancy rate with a high incidence of overstimulation and a premature LH surge. In order to overcome these problems, a new approach has been used, namely prior suppression of endogenous gonadotropins with a gonadotropin-releasing-hormone analog (LHRH) and subsequent ovarian stimulation with hMG. We present a case of ovarian stimulation with pure FSH during suppression of endogenous gonadotropins with the LHRH analog Buserelin. A clinical pregnancy was achieved in the first treatment cycle and led us to conclude that follicular development does not depend on LH stimulation. This could be of substantial interest in IVF programs.

Adult↗
PubMed1986

[A rare case of gonadal dysgenesis with 45, X-46, X ring X mosaic--case report].

This paper presents a case of gonadal dysgenesia with an uncommon structural X-chromosome abnormality (45, X-46, X, ring X mosaicism). The ring chromosome was not derived from an Y-chromosome as excluded by Q-banded analysis. The phenotypic expression of this abnormality caused typical Turner stigmata such as short stature, dysmorphic feature, streak ovaries with hypergonadotropic condition.

Adult↗
PubMed1985

[Are there genetic risk factors in the occurrence of choriocarcinoma?].

Now that we know about the genetic production mechanisms of diseases of the trophoblast, interest is concentrated on the question which risk factors can produce a disposition in the patient - seen from a clinico-genetic angle - towards malignancy of a complete mole. Many years before the genetic interrelations became known, there had been discussions on blood relationship as a possible aetiological factor in the production of chorionic carcinoma. Since consanguinity in preceding generations can lead to a selection of certain genotypes, this question was reexamined on a limited patients material (10 patients with chorionic carcinoma and 11 with mole). The negative result of this study contradicts - similar to other recent publications on this subject - the hitherto frequently advanced hypothesis that homozygotism is responsible, for a recessive "onko" gen, for rendering a complete mole malignant. Recent investigations, for example, point to a close correlation between the presence of a Y chromosome in a complete mole, and malignancy.

Choriocarcinoma↗