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Biomedical subjects

T Krieg

Publications and source records attributed to T Krieg.

At least 37 records · Page 2Linked to original sources
PubMed2003

Assessment of skin, joint, tendon and muscle involvement.

This report makes recommendations for standardized techniques of data gathering and collection regarding: 1) skin involvement 2) joint and tendon involvement, and 3) involvement of the skeletal muscles. The recommendations in this report derive from a critical review of the available literature and group discussion. Committee recommendations are considered appropriate for descriptive clinical investigation, translational studies and as standards for clinical practice. Skin involvement should be assessed using the modified Rodnan skin score. Joint involvement, when symmetric synovitis is present, could be best assessed by the DAS-28 as is utilized in rheumatoid arthritis. Clinical assessment should include a routinized evaluation for the presence and number of palpable tendon friction rubs. Muscle involvement should be screened for by performance of the serum creatine phosphokinase assay and assessment of proximal weakness. More specific testing including EMG, magnetic resonance imaging and muscle biopsy should be employed in those patients with clinically significant myopathy only.

Humans↗
PubMed2002

Expression of different survivin variants in gastric carcinomas: first clues to a role of survivin-2B in tumour progression.

Survivin is a novel member of the inhibitor of apoptosis family and determines the susceptibility of tumour cells to pro-apoptotic stimuli. Recently, we identified two novel alternative splice variants of survivin, differing in their anti-apoptotic properties: whereas the anti-apoptotic potential of survivin-DeltaEx3 is preserved, survivin-2B has lost its anti-apoptotic potential and may act as a naturally occurring antagonist of survivin. Because the in vivo expression of these alternative splice variants has not been explored so far, we analysed gastric carcinomas of different histological subtypes, grades and stages. Since no antibodies are currently available to determine the novel splice variants, quantitative reverse transcriptase polymerase chain reaction was performed, using RNA samples obtained from 30 different gastric carcinomas. Polymerase chain reactions products were quantified by densitometric evaluation. We found that all gastric carcinomas, irrespective of their histological types, grades or stages, express survivin-DeltaEx3, survivin-2B and survivin, the latter being the dominant transcript. Comparing the disease stages I+II with III+IV, expression of survivin and survivin-DeltaEx3 remained unchanged. In contrast, a significant (P=0.033) stage-dependent decrease in the expression of survivin-2B became evident. Our study demonstrates for the first time the expression of alternative splice variants in gastric carcinomas and provides a first clue to a role of survivin-2B in tumour progression.

Apoptosis↗
PubMed2001

Fibroblasts in mechanically stressed collagen lattices assume a "synthetic" phenotype.

Fibroblasts are subjected to changes of the mechanical force balance during physiological as well as pathological situations, such as wound healing, development of hypertrophic scars, and fibrogenesis. However, the molecular response and the changes in fibroblast gene expression upon mechanical stimulation remain poorly understood. As an in vitro model, human dermal fibroblasts were cultured within a three-dimensional network of fibrillar collagen either under high (stressed) or low tension (relaxed). cDNA microarray technology in combination with Northern blot analysis led to identification of mechano-responsive genes coding for extracellular matrix proteins, fibrogenic growth factors, protease inhibitors, components of focal adhesions, and the cytoskeleton. Application of biaxial strain to fibroblasts cultured on flexible silicone membranes revealed that the type of strain as well as the properties of the substrate induced different patterns of gene regulation. The transcriptional profile of mechanically induced genes in collagen lattices suggests that mechanical stimuli lead to a "synthetic" fibroblast phenotype characterized by induction of connective tissue synthesis while simultaneously inhibiting matrix degradation.

Actins↗
PubMed2001

CD40L induces matrix-metalloproteinase-9 but not tissue inhibitor of metalloproteinases-1 in cervical carcinoma cells: imbalance between NF-kappaB and STAT3 activation.

Matrix-metalloproteinases (MMPs) are essentially required for tumor cell invasion and metastasis. Production of precursor enzymes is regulated on transcriptional level, while activation of the pro-enzymes is tightly controlled by posttranscriptional mechanisms. The enzyme activity can be blocked by specific tissue inhibitors of MMPs (TIMPs). In cervical carcinomas strong up-regulation of the type IV collagenase MMP-9 had been demonstrated. We show that activation of CD40, a receptor highly expressed on cervical carcinomas, induces MMP-9 in cervical carcinoma cells, whereas TIMP-1 production inhibiting MMP-9 activity was not affected. This gene induction pattern corresponded to the differential activation of the transcription factor nuclear factor kappaB (NF-kappaB) regulating MMP-9, but not signal transducer and activator of transcription 3 (STAT3), which is involved in TIMP-1 gene regulation. Transient expression of the CD40-inducible NF-kappaB subunit p65 was sufficient for MMP-9 induction. Agents that suppressed CD40-mediated NF-kappaB activation also reduced MMP-9 induction, further supporting an important role of NF-kappaB in CD40-mediated MMP-9 induction. Our data suggest that CD40 expression in carcinoma cells might convert a CD40L-dependent immunological defense signal into a tumor-promoting signal. Selective CD40-mediated signaling through NF-kappaB but not STAT3 correlates to a shift of the balance between MMP-9 and TIMP-1 toward the protease.

Animals↗
PubMed2001

Effect of interleukin-10 on the gene expression of type I collagen, fibronectin, and decorin in human skin fibroblasts: differential regulation by transforming growth factor-beta and monocyte chemoattractant protein-1.

Interleukin-10 (IL-10) is a cytokine with many regulatory functions. In particular, IL-10 exerts neutralizing effect on other cytokines, and therefore IL-10 is thought to have important therapeutic implications. Recent reports suggest that IL-10 regulates not only immunocytes but also collagen and collagenase gene expression in fibroblasts. In this study, we investigated the effect of IL-10 on gene expression of extracellular matrix (ECM) proteins, such as type I collagen, fibronectin, and decorin, in human skin fibroblasts. Results of Northern blot analysis showed that both collagen I and fibronectin mRNAs were downregulated, while decorin gene expression was enhanced by IL-10 (10 ng/ml) time-dependently (6-24 h). alpha1(I) collagen and fibronectin mRNAs were decreased to one-third and one-fourth, respectively, by 50 ng/ml IL-10, whereas decorin mRNA was increased up to 2.7-fold by 50 ng/ml IL-10. Response to IL-10 by scleroderma fibroblasts was similar to that in normal dermal fibroblasts, with decreased expression levels of collagen and fibronectin and induced decorin mRNA levels. Transforming growth factor-beta (TGF-beta) is a crucial fibrogenic cytokine which upregulates the mRNA expression of collagen and fibronectin, whereas it downregulates decorin mRNA expression in fibroblasts. Monocyte chemoattractant protein-1 (MCP-1) has recently been shown to upregulate the type I collagen mRNA expression in cultured fibroblasts. We therefore examined whether IL-10 alters gene expression of ECM elicited by TGF-beta and MCP-1. Our results demonstrated that IL-10 downregulated the TGF-beta-elicited increase of mRNA expression of type I collagen and fibronectin, while partially recovering TGF-beta-elicited decrease of decorin expression in normal skin fibroblasts. By contrast, IL-10 did not alter the MCP-1-elicited upregulation of mRNA expression of either alpha1(I) collagen and decorin. Our data indicate that IL-10 differentially regulates TGF-beta and MCP-1 in the modulation of ECM proteins and therefore suggest that IL-10 plays a role in the regulation of tissue remodeling.

Blotting, Northern↗
PubMed2001

Adaptive antioxidant response protects dermal fibroblasts from UVA-induced phototoxicity.

In response to the attack of reactive oxygen species (ROS) produced upon UV irradiation, the skin has developed a complex antioxidant defense system. Here we report that, in addition to the previously published induction of manganese superoxide dismutase (MnSOD) activity, single and, to a higher extent, repetitive low-dose UVA irradiation also leads to a substantial upregulation of glutathione peroxidase (GPx) activity. This concomitant adaptive response of two antioxidant enzymes acting in the same detoxification pathway coincided with the protection from high-UVA-dose-induced cytotoxicity conferred by low-dose UVA preirradiation. Whereas an interval of 24 h did not, an interval of 12 h did lead to the induction of MnSOD activity and, under selenium-supplemented conditions, of GPx activity as well, conferring definite cellular protection from UVA-induced phototoxicity. Moreover, under selenium-deficient conditions, which abrogate the UVA-mediated induction of GPx activity, adaptive protection against the cytotoxic effects of high UVA doses was significantly lower compared with selenium supplementation. Isolated 4.6-fold overexpression of MnSOD activity in stably transfected fibroblasts led to specific resistance from UVA-mediated phototoxicity under selenium-deficient conditions. Collectively, these data indicate that the concomitant induction of MnSOD and GPx activity is related to the optimal adaptive protection from photooxidative damage. This adaptive antioxidant protection clearly depends on the irradiation interval and a sufficient selenium concentration, findings that may have important implications for the improvement of photoprotective and phototherapeutic strategies in medicine.

Antioxidants↗
PubMed2001

BM-40 and MMP-2 expression are not coregulated in human melanoma cell lines.

As published recently, suppression of BM-40 (osteonectin, SPARC) expression reduced the in vitro adhesive and invasive capacities of melanoma cells. In parallel, a decreased production of matrix metalloproteinase-2 (MMP-2) was observed in these cells indicating a close coregulation of these two proteins. However, analysis of 12 independently established melanoma cell lines, exhibiting different metastatic capacities, did not reveal a positive correlation between BM-40 or MMP-2 expression and the metastatic capacities of these cell lines. In addition, direct comparison of BM-40 and MMP-2 mRNA levels did not provide evidence for coregulation of these two proteins. This was further corroborated by the finding that exogenous BM-40 failed to alter synthesis and activation of proMMP-2.

Collagenases↗
PubMed2001

High expression and autoinduction of monocyte chemoattractant protein-1 in scleroderma fibroblasts.

Systemic sclerosis (SSc) is a connective tissue disease with unknown etiology characterized by excessive deposition of extracellular matrix in the skin as well as various internal organs. In the early stages of SSc, inflammatory infiltrates of mononuclear cells are found in the dermis, which is associated with increased collagen synthesis produced by activated fibroblasts. Monocyte chemoattractant protein-1 (MCP-1) is a predominant monocyte chemoattractant secreted by a variety of cell types, and recent in vivo and in vitro studies suggest the involvement of MCP-1 in tissue fibrosis. Here we demonstrate that cultured scleroderma fibroblasts, compared to fibroblasts from control skin, spontaneously express significantly elevated MCP-1 levels. Interestingly, exogenously administered MCP-1 stimulated autoinduction of MCP-1 mRNA. This effect was specific to scleroderma fibroblasts and abrogated by actinomycin D. These findings suggest that MCP-1 plays an important role in the induction of scleroderma by MCP-1 release from fibroblasts, which results in recruitment of monocytes to the skin. Moreover, increased responsiveness of scleroderma fibroblasts to MCP-1 could result in a continuation of the fibrotic response.

Cells, Cultured↗
PubMed2001

Role of stem cell factor and monocyte chemoattractant protein-1 in the interaction between fibroblasts and mast cells in fibrosis.

Mast cell infiltration and accumulation is known to occur in tissue fibrosis. Increased numbers of mast cells are detected in scleroderma or hypertrophic scar skin, however, neither the role of mast cells nor the interaction of fibroblasts and mast cells in fibrosis are fully understood. A growing body of evidence indicate that mast cells are rich source of cytokines, growth factors or chemokines, which are suggested to play an important role in the induction of fibrosis. Recent in vivo and in vitro studies suggest the involvement of monocyte chemoattractant protein-1 (MCP-1), a member of the C-C chemokine family, in fibrosis. Here, we examined the effect of stem cell factor (SCF), a mast cell growth factor, on MCP-1 gene expression in a human mast cell line, HMC-1, and as well as the effect of MCP-1 on alpha1(I) collagen gene expression in human skin fibroblasts. HMC-1 cells spontaneously expressed MCP-1 mRNA transcripts, which was detectable by in situ hybridization and Northern blot analysis. Stimulation with SCF further upregulated MCP-1 mRNA expression in a time- and dose-dependent manner, and stimulation with 100 ng/ml SCF for 24 h induced a 3-fold increase of MCP-1 mRNA expression in HMC-1 cells as compared with unstimulated cells. The concentration of MCP-1 protein in the culture supernatants of 50 ng/ml SCF-stimulated HMC-1 cells (3816+/-70 pg/ml) was significantly elevated compared to unstimulated cells (2588+/-130 pg/ml) (P < 0.01), as assessed by ELISA. Adversely, MCP-1 induced alpha1(I) collagen mRNA expression in normal skin fibroblasts dose-dependently. Finally, comparative study revealed that the concentration of SCF in the culture supernatants of scleroderma fibroblasts at primary passages was significantly increased (344.6+/-182.4 pg/ml), as compared with normal skin fibroblasts (72.4+/-20.2 pg/ml) (P<0.05). These results suggest that fibroblast-derived SCF upregulates MCP-1 expression and synthesis in mast cells, which acts on fibroblasts to enhance alpha1(I) collagen mRNA expression. Our data may indicate an important interaction of fibroblasts and mast cells, via SCF and MCP-1, in the induction of fibrosis.

Cell Communication↗
PubMed2001

Expression of monocyte chemoattractant protein-1 in the lesional skin of systemic sclerosis.

Systemic sclerosis (SSc) is a connective tissue disease with unknown etiology characterized by excessive deposition of collagen in the skin as well as various internal organs. One of the characteristic histological features is the presence of infiltrating mononuclear cells in the dermis in its early stage. As well as T cells, macrophages are implicated to play an important role in the initial pathologic changes associated with SSc by releasing fibrogenic cytokines, including transforming growth factor-beta or platelet-derived growth factor. However, the precise mechanism for increased monocyte/macrophage recruitment in the lesional skin of SSc is still not completely elucidated. Monocyte chemoattractant protein-1 (MCP-1) is a predominant monocyte chemoattractant secreted by various cells types including mononuclear cells, fibroblasts, smooth muscle cells, endothelial cells, or keratinocytes. In this study, we examined the expression of MCP-1 protein and mRNA in the lesional skin of seven patients with SSc by immunohistochemistry and in situ hybridization. Results of immunohistochemistry showed that MCP-1 was detected on infiltrating mononuclear cells and fibroblastic cells in scleroderma skin, whereas normal skin showed only minimal MCP-1 expression. We demonstrated the expression of MCP-1 mRNA in infiltrating mononuclear cells and keratinocytes in scleroderma and contact dermatitis skin. In addition, signals were also detected in fibroblasts in the lesional skin of scleroderma, whereas fibroblasts in normal skin and contact dermatitis skin did not express MCP-1 mRNA. These findings suggest that MCP-1 plays a role in recruiting monocyte/macrophages in the lesional skin of scleroderma and that activated fibroblasts in scleroderma are involved in this process.

Adult↗
PubMed2001

Increased deposition of fibulin-2 in solar elastosis and its colocalization with elastic fibres.

BACKGROUND: Fibulin-2 is a 195-kDa protein belonging to a novel family of extracellular matrix proteins that might be involved in microfibril and elastic fibre organization. OBJECTIVES: To determine the localization of fibulin-2 in relation to elastic fibres in normal skin and in solar elastosis characterized by increased elastotic material in the papillary dermis. METHODS: The expression and synthesis of fibulin-2 was investigated by means of in situ hybridization, immunohistochemistry and Western blot analysis in normal and photoaged skin. RESULTS: Immunohistochemistry and elastic tissue staining revealed that fibulin-2 deposition mainly colocalized with microfibrils and elastin fibres, with a marked staining of elastotic material in solar elastosis. Western blot analysis demonstrated that in photoaged skin fibulin-2 showed the same electrophoretic mobility as in sun-protected skin. However, in actinic elastosis the amount of fibulin-2 was significantly higher. In addition, smaller degradation products were detectable, presumably reflecting increased proteinase activity in photodamaged skin. CONCLUSIONS: This study shows that deposition of fibulin-2 and elastin is highly co-ordinated, indicating that this protein plays an important role in elastic fibre and microfibril formation in normal and actinically damaged skin.

Aged↗
PubMed2001

Contraction-dependent apoptosis of normal dermal fibroblasts.

The mechanisms underlying the contraction-dependent apoptosis of primary fibroblasts are of prime importance in understanding anchorage-dependent survival/apoptosis of dermal fibroblasts. As integrins are essential extracellular matrix receptors in fibroblasts, their role in anchorage-dependent apoptosis/survival of fibroblasts was analyzed. Primary human fibroblasts displayed a marked reduction of apoptosis in mechanically relaxed collagen matrices in the presence of adhesion-blocking antibodies against alpha1beta1 or alpha2beta1. Anti-alphavbeta3 antibodies had a considerably weaker effect. In additional experiments RD cells, which lack alpha2 integrin, displayed no apoptosis in mechanically relaxed collagen matrices. Their susceptibility to apoptosis was restored after transfection with functional alpha2 integrin, and it could be blocked again by adhesion-blocking antibodies against alpha2beta1 integrin. Therefore we conclude that apoptosis of human primary fibroblasts in contractile collagen matrices is - at least in part - inhibited by adhesion-blocking anti-integrin antibodies, suggesting that the mode of apoptosis in this case is different from anoikis. Further, apoptosis in a mechanically relaxed collagen matrix could be abrogated by depolymerization of F-actin using cytochalasin D and also by disturbing actin-myosin interaction using 2,3-butanedione monoxime, indicating a possible dependence of apoptosis on mechanical forces and/or cell shape.

Antibodies↗
PubMed2001

Linear IgA bullous dermatosis induced by atorvastatin.

Linear IgA bullous dermatosis (LABD) is an autoimmune blistering skin disease characterized by circulating IgA antibodies binding the basement membrane zone. In most cases the origin is not clear, but in a minority of cases LABD is drug induced. We describe a patient in whom linear IgA disease developed shortly after beginning therapy with atorvastatin. In Western blotting analysis we detected IgA and IgG class antibodies targeting a 97-kd protein. To our knowledge this is the first reported case of atorvastatin-induced LABD.

Anticholesteremic Agents↗
PubMed2001

Extensive human papillomavirus type 7-associated orofacial warts in an immunocompetent patient.

Human papillomavirus (HPV) type 7 is frequently found in butchers' warts and has been demonstrated in oral and facial warts of HIV-infected patients. The reservoirs of HPV7 and the route of transmission are still unclear. Here we describe an HIV-negative, otherwise healthy patient with extensive, recurrent orofacial papillomatosis whose immune status proved to be normal and who had no history of meat handling. HPV7 L1 gene DNA that differed in 3 point mutations from the HPV7 prototype could be detected in 2 morphologically distinct, perioral lesions by different PCR protocols. In situ hybridization confirmed the presence of HPV7 DNA in the nuclei of vacuolated cells of the granular layer. Our data show that HPV7 can lead to perioral, spiky warts and brownish plaques in immunocompetent patients who had never been working as a meat or fish handler.

Adult↗