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Biomedical subjects

K Brand

Publications and source records attributed to K Brand.

At least 19 recordsLinked to original sources

Reduced beta3-endonexin levels are associated with enhanced urokinase-type plasminogen activator receptor expression in ApoE-/- mice.

Proteolysis of extracellular matrix components is required for cell migration occurring in atherosclerotic lesion formation. In the present study, gene expression of the urokinase plasmingen activator receptor (uPAR) and underlying mechanisms were analyzed during the development of atherosclerosis in the aorta of apolipoprotein E-deficient mice (apoE(-/-)). A significant increase of uPAR expression was detected in the atherosclerotic tissue with advancing plaque-dimension. As uPAR gene transcription involves the transcription factor nuclear factor-kappaB (NF-kappaB), we analyzed nuclear NF-kappaB activity in vascular tissue of apoE-deficient mice. Congruent to uPAR, we could detect an increase in NF-kappaB activity, which underlines the chronic inflammatory component of the disease. Recently we reported that beta(3)-endonexin, a protein that modulates beta(3)-integrins, regulates uPAR expression through direct interaction with subunits of the NF-kappaB-complex. Herein we could show that beta(3)-endonexin protein is expressed in aortic tissue of mice. Moreover, in contrast to uPAR or NF-kappaB, the expression of beta(3)-endonexin was reduced in extracts of advanced atherosclerotic aortic tissue. The cytoplasmic protein beta(3)-endonexin regulates function of beta(3)-integrins. We revealed that integrin stimulation of endothelial cells led to an enhanced NF-kappaB activity and secretion of the NF-kappaB dependent chemokine monocyte chemoattractant protein-1 (MCP-1). The beta(3)-integrin dependent increase in MCP-1 was notedly reduced in cells that overexpressed beta(3)-endonexin. These results provide strong evidence that beta(3)-endonexin acts as a regulating factor in the integrin-mediated signal transduction and the present findings imply a pathophysiological role of beta(3)-endonexin in atherogenesis.

Animals↗

Retrospective evidence that the MHC (B haplotype) of chickens influences genetic resistance to attenuated infectious bronchitis vaccine strains in chickens.

Infectious bronchitis is a respiratory disease of chickens that is caused by the coronavirus infectious bronchitis virus (IBV). Virtually all broiler and layer breeder flocks are routinely vaccinated against IBV. Two hatches of 1-day-old chicks from four lines were mistakenly vaccinated for infectious bronchitis using a moderately attenuated vaccine designed for chicks of an older age. The vaccination resulted in high mortality, and chicks from three of four lines died with signs typical of infectious bronchitis. The mortality that occurred using this less-attenuated vaccine was significantly influenced by the genetic line, and the MHC (B) haplotype in chickens of three B congenic lines. B congenic chickens possessing the B*15 haplotype were resistant in contrast to chickens possessing the B*13 or B*21 haplotypes. Chicks from two further hatches of the four lines were vaccinated appropriately with a more attenuated IBV vaccine, and only limited chick mortality was seen. These retrospective data from two repeated hatches confirm earlier data indicating chicken genes influence resistance to IBV, and indicate for the first time that genes tightly linked to the B haplotype are relevant in resistance to IBV. Due to extenuating circumstances it was not possible to verify results with chicks from F2 matings. Factors that may enhance definition of the role of the B haplotype in immune response to IBV, and the desirability for further analysis of a B haplotype-linked influence on immunity to IBV are discussed.

Animals↗

Increased IkappaB kinase activity is associated with activated NF-kappaB in acute myeloid blasts.

NF-kappaB/Rel transcription factors are modulators of immune and inflammatory processes and are also involved in malignancy. Phosphorylation of the IkappaB inhibitors by the IkappaB kinase (IKK) complex leads to their proteasomal degradation, resulting in activated NF-kappaB. Here, we investigated the activation status of NF-kappaB and the IKK complex in acute myeloid leukemia (AML). Gelshift assays revealed an increased level of activated nuclear NF-kappaB in myeloid blasts. Both bone marrow and peripheral blood blasts from AML patients showed enhanced IKK activity relative to controls, whereas the IKK protein concentrations were comparable. In addition, an increased level of IkappaB-alpha was detected in AML blast cells, although this appeared to be insufficient to block nuclear translocation of NF-kappaB, also confirmed by immunofluorescence. In subtype M4 and M5 AML cells a more extensive NF-kappaB activation and higher IKK activity was found than in M1/M2 specimens. Isolated AML blasts cultured ex vivo responded to external stimulation (TNF, LPS) by further IKK activation, IkappaB degradation and NF-kappaB activation. Preincubation with the proteasome inhibitor PSI inhibited the NF-kappaB system in isolated AML blasts. This study established for the first time a dysregulation of IKK signaling in AML leading to increased NF-kappaB activity suggesting potential therapeutic avenues.

Acute Disease↗

Predominant role of toll-like receptor 2 versus 4 in Chlamydia pneumoniae-induced activation of dendritic cells.

Chlamydia pneumoniae is an obligate intracellular human pathogen causing diseases such as pneumonia, bronchitis, and pharyngitis. Because of its intracellular replication, cell-mediated immune responses are needed to mediate successful defenses of the host. Because dendritic cells play a central role in linking innate immunity and Ag-specific cell-mediated immune responses we asked whether dendritic cells are activated upon contact with C. pneumoniae and whether known Toll like receptors (TLR) are involved in this process. Here we show that C. pneumoniae was taken up by bone marrow-derived murine dendritic cells. Ingested C. pneumoniae appeared to be unable to develop mature inclusion inside dendritic cells. Furthermore, upon contact with C. pneumoniae dendritic cells were potently stimulated because NF-kappaB was activated and translocated to the nucleus, cytokines like IL-12p40 and TNF-alpha were secreted, and expression of MHC class II molecules, CD40, CD80, and CD86 was up-regulated. Importantly, secretion of cytokines as well as translocation of NF-kappaB were dependent on the presence of TLR2 and independent from TLR4 with the exception of IL-12p40 secretion, which was attenuated in the absence of either a functional TLR2 or 4. In conclusion, we show here that recognition of the Gram-negative bacterium C. pneumoniae depends largely on TLR2 and only to a minor extent on TLR4.

Active Transport, Cell Nucleus↗

Characterization of a novel human cell-cycle-regulated homologue of Drosophila dlg1.

Cell cycle defects have been associated with the process of carcinogenesis in many studies. Here we report the cloning and analysis of the novel gene KIAA0008 (GenBank acc. no. D13633). Chromosomal localization experiments assigned the gene to chromosome 14q22-q23. The mRNA transcript was found to be cell cycle regulated, expressed at S-phase, and maintained at both G2-and M-phases. In situ hybridization showed expression in proliferating colon and breast (tumor) tissues. Structurally, KIAA0008 shares homology with the Drosophila melanogaster discs large-1 (dlg1) tumor suppressor gene and membrane-associated guanylate kinase protein family members. The potential involvement of KIAA0008 in cell proliferation is discussed, along with its sequence identity and tissue distribution.

Adaptor Proteins, Signal Transducing↗

Transient interaction of activated platelets with endothelial cells induces expression of monocyte-chemoattractant protein-1 via a p38 mitogen-activated protein kinase mediated pathway. Implications for atherogenesis.

OBJECTIVE: Activated platelets induce alterations of chemotactic and adhesive properties of endothelial cells, a critical initial step in atherogenesis. We investigated the effect of transient interaction of activated platelets with cultured human umbilical vein endothelial cells (HUVECs) on secretion of monocyte chemoattractant protein-1 (MCP-1), a key molecule in monocyte chemotaxis and transmigration. METHODS AND RESULTS: Transient interaction of alpha-thrombin-activated platelets with endothelial cells for 10-120 min substantially induced endothelial secretion of MCP-1, monocyte chemotaxis and adhesion to HUVECs. Platelet-induced secretion of MCP-1 and monocyte-endothelium adhesion was reduced by the MAP kinase p38-specific inhibitor SB203580, but not by other kinase inhibitors including PD98059, wortmannin, or rapamycin. In addition, activated platelets induced transcription of a luciferase reporter construct containing a MCP-1 promotor, an effect that could be inhibited by SB203580. Overexpression of dominant-negative mutants of MAP kinase p38, CSBP2-(D168A) and CSBP2-(T180E,Y182E) reduced platelet-induced expression of MCP-1. CONCLUSIONS: Activation of the p38 MAP kinase and consecutive endothelial secretion of MCP-1 induced through transient interaction of activated platelets might play an important role in atherogenesis.

Anti-Inflammatory Agents↗

Effects of adenoviral wild-type p53 gene transfer in p53-mutated lymphoma cells.

The present study assessed the role of adenoviral vector-mediated wild-type p53 gene transfer in B lymphoma cells. Deficiency of p53-mediated cell death is common in human cancer contributing to both tumorigenesis and chemoresistance. Lymphoma cells are being considered as suitable targets for gene therapy protocols. Recently, we reported an adenoviral protocol leading to highly efficient gene transfer to B lymphoma cells. All lymphoma cell lines (n=5) tested here showed mutations in the p53 gene locus. The aim of this work was to transduce lymphoma cells with the wild-type p53 gene. Using this protocol, 88% of Raji, 75% of Daudi, and 45% of OCI-Ly8-LAM53 cells were transfected with the reporter gene green fluorescent protein at a multiplicity of infection of 200. The expression of green fluorescent protein in CA46 and BL41 cells was 27% and 42%, respectively. At this multiplicity of infection, growth characteristics of lymphoma cell lines were not changed significantly. In contrast, cells transduced with wild-type p53 gene showed an inhibition of proliferation as well as an increase in apoptosis. Cell loss by apoptosis after p53 gene transfer was up to 40% as compared to transduction with an irrelevant vector. In addition, we determined the effects of DNA damage produced by the DNA topoisomerase II inhibitor etoposide on wild-type p53 transfected lymphoma cells. In Ad-p53-transfected Raji cells, treatment with the drug resulted in a marked increase of cell loss in comparison to Ad-beta-Gal-transfected cells (45% vs. 77%). Interestingly, performing cytotoxicity studies, we could show an increased sensitivity of Raji and Daudi cells against immunological effector cells. In conclusion, transduction of wild-type p53 into lymphoma cells expressing mutated p53 was efficient and led to inhibition of proliferation and increase in apoptotic rate in some cell lines dependent on p53 mutation. This protocol should have an impact on the use of lymphoma cells in cancer gene therapy protocols.

Adenoviridae↗

Regression of large tumors expressing a suicide gene.

Using the HSV-tk/GCV system, complete remissions of tumors up to a size of 5 mm in diameter have been reported in mice and rats. In order to examine whether larger tumors of clinically relevant size can also be successfully treated, we established hepatic and peritoneal tumors consisting of retrovirally pretransduced tk-positive CC531 colon adenocarcinoma cells in syngenic Wag/Ola rats. In this model, we evaluated whether large tumors respond to therapy under the ideal condition of 100% gene transfer. Within 10 days, GCV treatment led to a marked regression of the adenocarcinomas. Tumors up to a size of 4000 mm3 could be completely eradicated. Passing through several stages of degeneration and cytolytic necrosis, a complete replacement by fibrous tissue was seen. There was no histological evidence for apoptosis and cell mediated immunity. These results suggest that complete regression of tumors of clinically relevant size can be achieved by direct toxic effects of the HSV-tk/GCV system if 100% of the cells are transduced.

Adenocarcinoma↗

Differential activation of cytokine secretion in primary human colonic fibroblast/myofibroblast cultures.

BACKGROUND: Fibroblasts and myofibroblasts are known to secrete a wide spectrum of cytokines, but the individual spectrum is tissue-specific. We investigated the effect of cell activation on cytokine secretion of isolated human colonic fibroblasts/myofibroblasts from control patients and patients with mucosal inflammation. METHODS: Primary cultures of human colonic submucosal fibroblasts/myofibroblasts were incubated with IL-1alpha (100 U/ml), IL-Ibeta (10 ng/ml), IL-10 (10 ng/ml), TNF (10 ng/ml), PMA (10 ng/ml), LPS (50 ng/ml), IL-4 (10 ng/ml), or a combination of IL-1 and TNF. Secreted cytokines were determined by ELISA. NF-kappaB activation was demonstrated by electrophoretic mobility-shift assays (EMSA). RESULTS: Incubation of colonic fibroblasts/myofibroblasts with IL-1, LPS, TNF and PMA induced secretion of IL-6, IL-8, M-CSF and GM-CSF. IL-8 and IL-6 secretion could be stimulated by IL-1alpha, IL-1beta, TNF, PMA and LPS within 6 h of incubation. IL-6 secretion was stimulated from 0.5 +/- 0.01 pg/h x microg fibroblast protein to 18.5 +/- 2.6 pg/h x microg fibroblast protein with IL-1beta (P < 0.01). IL-8 secretion was stimulated from 1.0 +/- 0.1 pg/h x microg fibroblast protein to 41.1 +/- 3.6 pg/h x microg (P < 0.005). IL-4 and IL-10 did not change cytokine secretion significantly. No significant differences between cultures from normal and inflamed mucosa were observed. TNF and IL-1 induced NF-kappaB activation. ALLN, a proteasome and NF-kappaB activation inhibitor, reduced TNF-mediated IL-8, GM-CSF and M-CSF induction significantly, whereas induction of IL-6 secretion remained unchanged. CONCLUSION: Human colonic myofibroblasts can secrete large amounts of IL-6, IL-8, M-CSF and GM-CSF upon stimulation. The induction of IL-8, M-CSF and GM-CSF, but not of IL-6 secretion, is mediated mainly by NF-kappaB activation. The cytokine profile and the total amounts of cytokines released suggest that colonic myofibroblasts can play a role in leukocyte recruitment and during mucosal inflammation. They therefore have to be regarded as an important part of the mucosal immune system.

Adult↗

The influence of hypothermia on outer hair cells of the cochlea and its efferents.

Transient evoked otoacoustic emissions (TEOAE) were recorded in 21 guinea-pigs undergoing hypothermia. The minimal average body temperature during cooling was 26 degrees C/24.9 degrees C measured orally or rectally, respectively. The animals were subsequently warmed to normal body temperature. A clear influence of body temperature on TEOAE could be documented. During cooling the amplitude and reproducibilities decreased, disappearing completely at a mean temperature below 28.5 degrees C (oral) and 27.3 degrees C (rectal). The emissions reappeared during rewarming at a mean temperature of 30.1 degrees C (oral) and 30.8 degrees C (rectal). Contralateral auditory stimulation (CAS) led to a decrease of the amplitudes of TEOAE during cooling down to a mean of 33 degrees C/32 degrees C (oral/rectal temperature). During rewarming, influences of the CAS could be recognized, again at an oral temperature above 35 degrees C. The changes to the TEOAE observed in these experiments suggest that hypothermia affects not only the outer hair cells (OHC) of the cochlea but also the efferent supply to the cochlea.

Acoustic Stimulation↗

Treatment of colorectal liver metastases by adenoviral transfer of tissue inhibitor of metalloproteinases-2 into the liver tissue.

Metastatic disease is the leading cause of death in cancer patients. Here, we describe a novel gene therapeutic strategy for prevention of metastatic spread by providing a suitable defense mechanism for the target organ. The production of metalloproteinase (MMP) enzymes by cancer cells is critical for local invasion and for infiltration of metastatic cells into distant sites. Using a nude mouse model of colorectal liver metastasis, we have overexpressed the MMP inhibitor, tissue inhibitor of MMP-2 (TIMP-2) in the liver prior to, or following, tumor challenge by metastatic LS174T cells in vivo. Transduction of approximately 50% of hepatocytes resulted in 95% reduction in metastasis after tumor challenge compared with controls. Furthermore, TIMP-2 gene transfer into livers with preexisting metastatic spread resulted in a 77% reduction in tumor cell growth. Our data imply that MMP activity of metastatic cancer cells is required for spread and subsequent tumor growth and that enhancing antiproteolytic defense mechanisms in target organs represents a novel form of cancer gene therapy.

Adenoviridae↗

Selective depletion of heat shock protein 70 (Hsp70) activates a tumor-specific death program that is independent of caspases and bypasses Bcl-2.

Heat shock protein 70 is an antiapoptotic chaperone protein highly expressed in human breast tumors and tumor cell lines. Here, we demonstrate that the mere inhibition of its synthesis by adenoviral transfer or classical transfection of antisense Hsp70 cDNA (asHsp70) results in massive death of human breast cancer cells (MDA-MB-468, MCF-7, BT-549, and SK-BR-3), whereas the survival of nontumorigenic breast epithelial cells (HBL-100) or fibroblasts (WI-38) is not affected. Despite the apoptotic morphology as judged by electron microscopy, the asHsp70-induced death was independent of known caspases and the p53 tumor suppressor protein. Furthermore, Bcl-2 and Bcl-X(L), which protect tumor cells from most forms of apoptosis, failed to rescue breast cancer cells from asHsp70-induced death. These results show that tumorigenic breast cancer cells depend on the constitutive high expression of Hsp70 to suppress a transformation-associated death program. Neutralization of Hsp70 may open new possibilities for treatment of cancers that have acquired resistance to therapies activating the classical apoptosis pathway.

Adenoviridae↗

Platelets induce alterations of chemotactic and adhesive properties of endothelial cells mediated through an interleukin-1-dependent mechanism. Implications for atherogenesis.

Platelets and alterations of chemotactic and adhesive properties of endothelium play an important role in the pathophysiology of atherosclerosis. We investigated the effect of platelets on secretion of monocyte chemotactic protein-1 (MCP-1) and on surface expression of intercellular adhesion molecule-1 (ICAM-1) of cultured endothelium. Pretreatment of cultured monolayers of endothelial cells with alpha-thrombin-activated platelets significantly enhanced secretion of MCP-1 and ICAM-1 surface expression (P<0.01) that could be inhibited by interleukin-1 (IL-1) antagonists by approximately 40%. Activation of transcription factor nuclear factor-kappaB (NF-kappaB) which regulates transcription of early inflammatory response genes such as MCP-1, was significantly increased in endothelial cells treated with activated platelets via an IL-1 mediated mechanism as determined by electrophoretic mobility shift assay (EMSA) and kappaB-dependent transcriptional activity. In trans-well experiments, alpha-thrombin-activated platelets enhanced IL-1-dependent surface expression of vitronectin receptor (alpha(v)beta(3)) on the luminal aspect of endothelial monolayers and promoted alpha(v)beta(3)-mediated platelet/endothelium adhesion that could be inhibited by the antiadhesive peptides GRGDSP and c(RGDfV). We conclude that activated platelets induce significant changes in chemotactic (secretion of MCP-1) and adhesive (surface expression of ICAM-1 and alpha(v)beta(3)) properties of cultured endothelium. These findings imply a potential pathophysiological mechanism of platelets in an early stage of atherogenesis.

Blood Platelets↗

Efficient gene transfer into lymphoma cells using adenoviral vectors combined with lipofection.

Tumor cells, such as lymphoma cells, are possible targets for gene therapy. In general, gene therapeutic approaches require efficient gene transfer to host cells and sufficient transgene expression. However, lymphoma cells previously have been demonstrated to be resistant to most of the currently available gene transfer methods. The aim of this study was to analyze various methods for transfection of lymphoma cells and to improve the efficiency of gene delivery. In accordance with previously published reports, lymphoma cells were demonstrated to be resistant to lipofection and electroporation. In contrast, we present an improved adenoviral protocol leading to highly efficient gene transfer to lymphoma cell lines derived from B cells as well as primary lymphoma cells being achieved with an adenoviral vector system encoding the beta-galactosidase protein. At a multiplicity of infection of 200, up to 100% of Daudi cells and Raji cells and 70% of OCI-Ly8-LAM53 cells could be transfected. Even at high adenoviral concentrations, no marked toxicity was observed, and the growth characteristics of the lymphoma cell lines were not impaired. The transfection rates in primary cells derived from six patients with non-Hodgkin's lymphoma were 30-65%, respectively. Transfection efficiency could be further increased by addition of cationic liposomes to adenoviral gene transfer. Furthermore, we examined the expression of the Coxsackie-adenoviral receptor (CAR) and the integrin receptors on the lymphoma cell surface. Flow cytometric analysis showed that 88% of Daudi cells, 69% of Raji cells, and 6% of OCI-Ly8-LAM53 cells expressed CAR on the cell surface. According to our data, adenoviral infection of lymphoma cells seems to be mediated by CAR. In contrast, integrin receptors are unlikely to play a major role, because lymphoma cells were negative for alphavbeta3-integrins and negative for alphavbeta5-integrins. In conclusion, this study demonstrates that B-lymphoma cell lines and primary lymphoma cells can be efficiently transfected using an adenoviral vector system. By adding cationic liposomes, the efficiency of adenoviral gene transfer to primary tumor cells could be further improved. This protocol may have an impact on the use of lymphoma cells in cancer gene therapy.

Adenoviridae↗

Nuclear factor-kappa B activity and intestinal inflammation in dextran sulphate sodium (DSS)-induced colitis in mice is suppressed by gliotoxin.

In acute DSS-induced colitis nuclear factor (NF)-kappaB-dependent inflammatory cytokines including IL-1 and tumour necrosis factor-alpha (TNF-alpha) are up-regulated. Here we examined the effects of gliotoxin, a fungal metabolite known to inhibit NF-kappaB activity, on cytokine production by a mouse cell system in vitro and on intestinal inflammation and NF-kappaB activation in vivo. In vitro gliotoxin decreased TNF-alpha gene expression and protein production by RAW-264.7 mouse macrophage-like cells stimulated with lipopolysaccharide. In vivo, gliotoxin treatment of mice was begun on day 3 of 5% DSS application dissolved in the drinking water and continued until day 8. Gliotoxin treatment dose-dependently down-regulated colonic inflammation as assessed histologically and in parallel there was a suppression of colonic TNF-alpha and IL-1alpha mRNA expression on day 8 as analysed by semiquantitative reverse transcriptase-polymerase chain reaction (P < 0.01). Furthermore, colonic NF-kappaB DNA-binding activity was increased in DSS-induced colitis and was suppressed by gliotoxin. These results demonstrate the essential role of NF-kappaB in DSS-induced colitis and indicate a molecular approach to the treatment of intestinal inflammatory disorders.

Animals↗

Heat shock protein 70 is required for the survival of cancer cells.

The major stress-inducible heat shock protein, Hsp70, is a chaperone protein abundantly and preferentially expressed in human tumors and tumor cell lines. Owing to the ability of Hsp70 to protect cells from a wide range of apoptotic and necrotic stimuli, it has been assumed that Hsp70 may confer survival advantage to tumor cells. To investigate this hypothesis in human tumor cell lines, we generated an adenovirus expressing antisense Hsp70 (Ad.asHsp70). The effective and specific depletion of Hsp70 by Ad.asHsp70 resulted in massive cell death of all tumorigenic cell lines tested (carcinomas of breast, colon, prostate and liver as well as glioblastoma). In spite of an effective depletion of Hsp70, Ad.asHsp70 had no effect on the survival or growth of fetal fibroblasts or non-tumorigenic epithelial cells of breast or prostate. Anti-apoptotic proteins Bcl-2, Bcl-XL and CrmA as well as peptide-inhibitors of caspases, DEVD-CHO and zVAD-FMK, failed to rescue tumor cells from Ad.asHsp70-induced cell death. These results indicate that the high expression of Hsp70 is a prerequisite for the survival of human cancer cells of various origins and reveal Hsp70 as the only protein described so far whose expression is specifically needed for the survival of tumorigenic cells.

Adenoviridae↗

Zolpidem and promethazine in pre-anaesthetic medication. A pharmacopsychological approach.

This study dealt with the question: What are the effects of different doses of the benzodiazepine-like agent zolpidem and the phenothiazine derivative promethazine on mood in pre-anaesthetic medication? Subjects were 192 female and male patients awaiting elective surgery. Two drugs were administered to the patients in the evening before anaesthesia according to a 3 x 2 factorial randomized double-blind design. The first drug factor was zolpidem (8.03 vs. 16.06 mg) versus placebo. These drugs were combined with the second drug factor, either promethazine (50 mg) or placebo. In summary, the results confirm the hypothesis that zolpidem 8.03 mg can induce paradoxical effects, especially of anxiety, 1 h after application. When the dosage is doubled, no adverse effects are found, but there are no effects different from placebo either. Men could probably be described as a risk population for the adverse effects of zolpidem 8.03 mg. Furthermore, selective deactivating effects of promethazine 50 mg were shown in this study. In addition to these anaesthesiological aspects, this study showed promethazine to be useful as a research tool, suitable as a reference drug to detect deactivating effects. The multidimensional self-report inventory BSKE(EWL) (Befindlichkeitsskalierung durch Kategorien und Eigenschaftswörter) detected the expected drug effects, indicating that this instrument is suitable for further pharmacopsychological research.

Adult↗