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Biomedical subjects

Elena Neumann

Publications and source records attributed to Elena Neumann.

12 recordsLinked to original sources
PubMed2006

The potential of adiponectin in driving arthritis.

Articular adipose tissue is a ubiquitous component of human joints, but its local functions are largely unknown. Because recent studies revealed several links between adipose tissue, adipocytokines, and arthritis, we investigated the expression of the adipocytokine adiponectin and its functional role in articular adipose tissue and synovium of patients with different arthritides. In contrast to its protective role in endocrinological and vascular diseases, adiponectin was found to be involved in key pathways of inflammation and matrix degradation in the human joint. The effects of adiponectin in human synovial fibroblasts appear to be highly selective by inducing only two of the main mediators of rheumatoid arthritis pathophysiology, IL-6 and matrix metalloproteinase-1, via the p38 MAPK pathway. Owing to the observation that these effects could be inhibited by different TNF-alpha inhibitors, adipocytokines such as adiponectin may also be key targets for therapeutic strategies in inflammatory joint diseases. In summary, articular adipose tissue and adipocytokines cannot be regarded as innocent bystanders any more in chronic inflammatory diseases such as arthritis.

Adalimumab↗
PubMed2005

Developing the concept of adoptive cellular gene therapy of rheumatoid arthritis.

Progressive destruction of articular cartilage and bone is the pivotal problem of rheumatoid arthritis (RA). Joint destruction is the cause of severe disability and determines the long-term outcome of disease. Conventional therapy does not control this destructive process sufficiently and the anti-rheumatic drugs available today can cause severe systemic adverse effects. Local application of chondroprotective and osteoprotective agents by means of gene therapy would be an attractive alternative to conventional therapy of RA and could provide long-term expression of the therapeutic agents and minimize systemic adverse effects. For this purpose, we have developed the concept of adoptive cellular gene therapy. This treatment strategy is based on using genetically engineered cells that home specifically to sites of autoimmune inflammation and thus allow local delivery of therapeutic gene products. Ex vivo transduction of these cells avoids systemic exposure of the host to the transgene-encoding vector and thus adds to the safety of this approach. In this article of the CIS Spring School in Autoimmune Diseases 2005 proceedings, we review our work on developing the strategy of adoptive cellular gene therapy and summarize recent advances in the evaluation of therapeutic effects and the identification of novel therapeutic targets.

Adoptive Transfer↗
PubMed2004

Functional genomics of fibroblasts.

PURPOSE OF REVIEW: Successful analysis of the pathophysiology of rheumatoid arthritis requires the functional understanding of interactions between different cell types and the cell matrix, intracellular signaling pathways, as well as between cartilage, bone, and synovium in rheumatoid arthritis. During the review period, molecular biology has provided and used a growing number of tools to screen the genome such as gene and protein chips, haplotype analysis, and single nucleotide polymorphism analysis, resulting in various novel findings with considerable impact on the overall understanding of rheumatoid arthritis. RECENT FINDINGS: Key issues that have been addressed and elucidated by numerous research groups are the regulation and modulation of synovial fibroblast metabolism and activation by proinflammatory cytokines and chemokines. In addition, examination of adhesion processes and neoangiogenesis has revealed new insights into the interaction network between rheumatoid synovial fibroblasts and the surrounding matrix and cells. Finally, a more detailed view of activation of these fibroblasts has been obtained by analysis of the molecular balance between cellular activation and regulation of apoptosis. SUMMARY: Although high throughput molecular analysis methods provided an ample amount of novel data, it needs to be stressed that a one-method approach of gene expression (eg, by array analysis) is not sufficient to validate the gene/gene product as a new therapeutic target. Therefore, the next steps are the so-called functional genomics or functionomics, which intend to reveal relations between the obtained data and to unveil their interactions for a better understanding of the pathogenesis and the mechanisms that are operative in rheumatoid arthritis.

Apoptosis↗
PubMed2004

Laser-mediated microdissection as a tool for molecular analysis in arthritis.

Most current approaches to the analysis of gene expression in arthritic tissue samples are based on RNA isolated either from cultured synovial cells or from synovial biopsies. However, this strategy does not distinguish between specific gene expression profiles of cells originating from separate tissue areas. Therefore, we established the combination of laser-mediated microdissection and RNA arbitrarily primed polymerase chain reaction (RAP-PCR) for differential display to analyze profiles of gene expression in histologically defined areas of arthritic tissue. Cryosections derived from synovial tissue were used to obtain cell samples from different tissue areas using a microbeam laser microscope. RNA was isolated and analyzed using nested RAP-PCR to generate a fingerprint of the expressed gene sequences. Differentially expressed bands were isolated, cloned, and sequenced. Differential expression of identified sequences was confirmed by in situ hybridization and immunohistochemistry.

Arthritis↗
PubMed2003

Albumin-based drug delivery as novel therapeutic approach for rheumatoid arthritis.

We reported recently that albumin is a suitable drug carrier for targeted delivery of methotrexate (MTX) to tumors. Due to pathophysiological conditions in neoplastic tissue, high amounts of albumin accumulate in tumors and are metabolized by malignant cells. MTX, covalently coupled to human serum albumin (MTX-HSA) for cancer treatment, is currently being evaluated in phase II clinical trials. Because synovium of patients with rheumatoid arthritis (RA) shares various features observed also in tumors, albumin-based drug targeting of inflamed joints might be an attractive therapeutic approach. Therefore, the pharmacokinetics of albumin and MTX in a mouse model of arthritis was examined. Additionally, uptake of albumin by synovial fibroblasts of RA patients and the efficacy of MTX and MTX-HSA in arthritic mice were studied. The results show that when compared with MTX, significantly higher amounts of albumin accumulate in inflamed paws, and significantly lower amounts of albumin are found in the liver and the kidneys. The protein is metabolized by human synovial fibroblasts in vitro and in vivo. MTX-HSA was significantly more effective in suppression of the onset of arthritis in mice than was MTX. In conclusion, albumin appears to be a suitable drug carrier in RA, most likely due to effects on synovial fibroblasts, which might increase therapeutic efficacy and reduce side effects of MTX.

Albumins↗
PubMed2003

Evaluation of differentially expressed genes by a combination of cDNA array and RAP-PCR using the AtlasImage 2.0 software.

Evaluation of genes regulated differentially is essential for the development of therapeutic approaches in multifactorial diseases. To characterize gene expression profiles in multifactorial inflammatory and malignant diseases such as rheumatoid arthritis (RA) or colon adenoma (CA), RNA arbitrarily primed PCR (RAP-PCR) combined with cDNA array hybridization were performed and evaluated using an array-specific software.RNA of synovial fibroblasts from patients with RA and osteoarthritis (OA), and laser microdissected normal and colon adenoma tissue was used. RAP-PCR reactions were hybridized to cDNA array membranes. Arrays were analyzed by phosphor imaging, and the AtlasImage 2.0 software with different normalization settings. The AtlasImage 2.0 software was a useful tool to evaluate differentially expressed genes. However, software settings were needed to be optimized for every experimental approach and should be used without changes for all experiments. To compare RA vs. OA synovial fibroblasts and normal vs. CA expression patterns, global normalization using the sum method is recommended.

Arthritis↗
PubMed2003

Thioredoxin reductase 1 expression in colon cancer: discrepancy between in vitro and in vivo findings.

Thioredoxin and thioredoxin reductase 1 (TR1) are redox proteins that have been implicated in cellular events such as proliferation, transformation, and apoptosis. Analysis of the expression and localization of TR1 in different normal and cancer cell lines and in colon tissues (normal, neoplastic, or inflamed) was performed using reverse transcription-PCR and in situ hybridization. TR1 mRNA was expressed in all analyzed tissues with TR mRNA-positive cells restricted to the stroma of colon crypts, partly being CD3 or CD56 positive. In neoplastic areas of colonic cancer tissue, a loss of TR was obvious. None of the epithelial cells in colonic mucosa expressed TR mRNA, whereas more than 70% of HT-29 cells grown in monolayer were positive for TR. In contrast, HT-29 cells, grown as spheroids or as tumors in SCID mice, were negative for TR. In contrast to these in vitro findings and previous studies, there is no evidence that TR plays a significant role in vivo in normal cell growth in colonic epithelial cells. The mechanism underlying the loss of TR1-positive/CD3-positive/CD56-positive cells or the biologic consequence of this phenomenon observed in neoplastic colonic tissue remains to be clarified.

Animals↗
PubMed2002

Local production of complement proteins in rheumatoid arthritis synovium.

OBJECTIVE: Complement has been repeatedly implicated in the pathogenesis of rheumatoid arthritis (RA) based on studies showing reduced levels of native complement components and increased levels of complement metabolites in plasma, synovial fluid (SF), and synovial tissue (ST) of RA patients. However, there is limited information on local production and activation of key factors of the complement cascade in RA synovium and their potential modulation by novel anticytokine therapies. This study was undertaken to characterize the expression of complement proteins and receptors in RA SF and ST. METHODS: Using in situ hybridization, immunohistochemistry, and Western blot techniques, we assessed the presence of complement proteins C3, factor B (FB), and C5b-9, as well as the expression of complement receptors C3aR and C5aR in rheumatoid synovium. C3 and FB levels in SF were determined by enzyme-linked immunosorbent assay. Functional assessment was performed by examining the effects of soluble tumor necrosis factor receptor (sTNFR) p55 gene transfer in the SCID mouse model of RA. RESULTS: Complement proteins and receptors could be localized in all RA synovial specimens, whereas in osteoarthritis (OA) synovium, only a few, single cells expressed complement proteins and receptors. No differences were noted in the concentration of C3 between RA and OA in SF; however, FB levels were markedly reduced in RA versus OA SF. In RA synovium, in contrast to OA synovium, local expression of complement factor and complement receptor messenger RNA was found throughout the various ST compartments, suggesting that activation of the complement cascade occurs in all parts of the rheumatoid synovium. Moreover, C5aR expression was up-regulated following overexpression of sTNFR p55 by adenovirus-based gene transfer. CONCLUSION: In summary, local complement production and activation may play an important role in RA, and specific modulation and inhibition of local complement production could be an attractive therapeutic target for RA.

Aged↗