Biomedical subjects

Anja K Bosserhoff

Publications and source records attributed to Anja K Bosserhoff.

6 recordsLinked to original sources

PubMed2003

Specific expression and regulation of the new melanoma inhibitory activity-related gene MIA2 in hepatocytes.

The novel human gene MIA2 encoding a melanoma inhibitory activity (MIA) homologous protein was identified by a GenBank(TM) search. MIA2, together with MIA, OTOR, and TANGO, belongs to the novel MIA gene family sharing important structural features, significant homology at both the nucleotide and protein levels, and similar genomic organization. In situ hybridization, reverse transcriptase-PCR, and Northern blots presented a highly tissue-specific MIA2 expression pattern in the liver. Promoter studies analyzing transcriptional regulation of MIA2 revealed an HNF-1-binding site at position -236 controlling hepatocyte-specific expression. Mutation of the site led to a complete loss of promoter activity in HepG2 cell. Further sites detected in the MIA2 promoter were consensus binding sites for SMAD and STAT3, Consistently, stimulation of MIA2 mRNA expression occurred by treatment with interleukin-6, transforming growth factor-beta, and conditioned medium from activated hepatic stellate cells. In accordance with these results, MIA2 mRNA was found to be increased in liver tissue of patients with chronic hepatitis C infection compared with controls. MIA2 mRNA levels were significantly higher in patients with severe fibrosis or inflammation than in patients with less severe fibrosis or inflammation. In summary our data indicate that MIA2 represents a potential novel acute phase protein and MIA2 expression responds to liver damage. The increased transcription in more severe chronic liver disease suggests that MIA2 may serve as a marker of hepatic disease activity and severity.

Acute-Phase Proteins↗

PubMed2003

Establishing the protein MIA (melanoma inhibitory activity) as a marker for chondrocyte differentiation.

Melanoma inhibitory activity (MIA), also referred to as cartilage derived retinoic acid-sensitive protein (CD-RAP), is detected physiologically in cartilage tissue and pathologically in malignant melanomas. To measure MIA/CD-RAP quantitatively we developed a sensitive ELISA system. Recently, we described diagnostic applications of the MIA-ELISA in patients with cartilage diseases. The study described herein was performed to determine whether there is any relation between MIA/CD-RAP levels and the degree of chondrocyte differentiation in tissue culture and to analyse whether MIA/CD-RAP may serve as a useful marker to control chondrocyte differentiation in in vitro tissue engineering. Our data provide evidence that measuring MIA in tissue culture supernatant by a quantitative ELISA can be used as a marker for differentiated chondrocytes.

Biomarkers↗

PubMed2003

Upregulation of HMG1 leads to melanoma inhibitory activity expression in malignant melanoma cells and contributes to their malignancy phenotype.

Malignant transformation of melanocytes to melanoma cells closely parallels activation of melanoma inhibitory activity (MIA) expression. We have previously shown that upregulation of MIA occurs on a transcriptional level and involves the highly conserved region (HCR) promoter element. We further observed that the HCR element interacts with the melanoma-associated transcription factor (MATF) and thereby confers strong promoter activation. In this study we identify the peptide sequence of MATF and show that it is identical with the transcription factor HMG1. HMG1 was upregulated in malignant melanoma cells and further activated by hypophosphorylation. Stable antisense-HMG1 expression in melanoma cells led to the reduction of MIA promoter activity and protein expression, indicating that HMG1 is a potent regulator of MIA expression. Interestingly, chromatin immunoprecipitation and electrophoretic mobility shift experiments indicated that HMG1 and the NF-kappa B family member p65 both interact and bind to the HCR promoter element. In summary, our study proves HMG1 and p65 to be important factors in MIA regulation and melanoma progression.

Amino Acid Sequence↗

PubMed2002

Down-regulation of COOH-terminal binding protein expression in malignant melanomas leads to induction of MIA expression.

Malignant transformation of melanocytes to melanoma cells closely parallels activation of MIA expression and involves a promoter region that we referred to previously as a HCR (highly conserved region). The HCR element interacts with the melanoma-associated transcription factor and confers strong activation of the promoter. Furthermore, mutation and deletion studies described in this study revealed that the permissive site for cell-specific promoter activity was located directly 5' to the HCR region. Changes in the DNA sequence 5' adjacent to the melanoma-associated transcription factor binding site led to an MIA promoter activity in benign melanocytes and nonmelanocytic cells that usually do not express MIA. Detailed analysis revealed binding of T-cell factor family transcription factors to the repressor element. Because this family is known to interact with COOH-terminal binding protein, we explored the role of COOH-terminal binding protein 1(CtBP1) in silencing MIA gene expression. By reporter gene analysis, we determined a strict negative regulation of MIA promoter activity in melanoma cells by CtBP1. Furthermore, we observed strong expression of CtBP1 in primary melanocytes but a loss of wild-type CtBP1 expression in malignant melanoma in vitro and in vivo. Therefore, we speculate that CtBP1 has an important negative role in MIA regulation, and loss of CtBP1 is implicated in melanoma progression.

Alcohol Oxidoreductases↗

PubMed2002

Correlation of a novel matrix protein with the degree of cartilage degradation.

Cartilage-derived retinoic acid-sensitive protein (CD-RAP), also referred to as melanoma-inhibiting activity (MIA), is detected physiologically only in cartilage tissue and pathologically in malignant melanoma. Recent studies indicated that this protein might be useful as a marker for altered joint metabolism or damage. The purpose of this study was to evaluate whether there is any correlation between the degree of cartilage degradation and levels of this protein. In a prospective cross-sectional study, synovial fluid samples were obtained from 67 consecutive patients undergoing surgery of the knee joint. The degree of cartilage degradation was determined intraoperatively using the Outerbridge and Noyes classifications. MIA/CD-RAP was measured by a commercially available enzyme-linked immunosorbent assay (ELISA). The marker levels were compared against the Outerbridge and Noyes classifications and the correlation coefficients were calculated. At advanced stages of cartilage degradation, there were decreased synovial fluid levels of MIA/CD-RAP. The correlation coefficients were -0.449 and -0.418 for the Outerbridge and Noyes classifications, respectively, with large 95% confidence intervals. While the physiological function of MIA/CD-RAP is still unclear, the results indicate that MIA/CD-RAP levels depend on the degree of cartilage degradation. Despite the high interindividual variations, MIA/CD-RAP might be useful as a marker to monitor degenerative joint lesions.

Adolescent↗

PubMed2002

Efficient transfection method for primary cells.

Transfection of primary cells and stem cells is a problem in the laboratory routine and further in tissue engineering and gene therapy. Most methods working effectively for cell lines in culture fail to transfect primary cells. Here we describe the use of the Nucleofector technology developed by amaxa biosystems. We were able to transfect primary human melanocytes, human coronary smooth muscle cells, human chondrocytes, and human mesenchymal stem cells with high efficiencies (28.9-45.3%). All primary cell types failed to be transfected satisfactorily by methods based on liposome-mediated transfection in our hands. The viability of the transfected cells varied between 11.2% and 75% in comparison to untreated cells. Only 200,000 cells per transfection sample were needed. In summary, this method presents an effective and fast mean for transfection of primary and stem cells demonstrated by four cell types which are only transfected with low efficiency by other methods.

Cell Survival↗