Localization of elastase and tumor necrosis factor alpha mRNA by non-radioactive in situ hybridization in cultures of alveolar macrophages

Impact of c-Met expression on angiogenesis in soft tissue sarcomas: correlation to microvessel-density

PURPOSE AND METHODS

The c-Met protein is significant for oncogenesis and angiogenesis within the c-Met/HGF/SF-mediator system. The aim of this study was the analysis of c-Met immunoexpression/-synthesis and microvessel density as parameters for angiogenesis and prognosis in 115 soft tissue sarcomas.

RESULTS

C-Met could be detected by immunohistochemistry in 87% of sarcomas. In all, 60.9% of cases exhibited absent or faint expression of c-Met protein, and 39.1% high expression of c-Met protein with a correlation between tumor grading and c-Met immunoexpression. Using in situ hybridization with detection of c-met-mRNA-transcripts, c-Met protein synthesis within tumor cells could be demonstrated. A statistically significant correlation between c-Met immunoexpression and tumor microvessel density was found. No prognostic value of c-Met expression and microvessel density could be detected in 56 patients with clinical follow-up ( P=0.8506 and P=0.9329 for disease-free survival).

CONCLUSIONS

The results underline a role of c-Met as an oncoprotein in soft tissue sarcomas with correlation between immunoexpression and grading. The statistically significant correlation between c-Met expression and microvessel density (as a parameter of tumor angiogenesis) suggests an angiogenic function of the c-Met/HGF/SF mediator system in malignant mesenchymal tumors.

Expression of type I and IV collagen mRNAs in healing gastric ulcers--a comparative analysis using isotopic and non-radioactive in situ hybridization

The sensitivity and practicability of in situ hybridization methods utilizing isotopic or non-radioactive labeling were compared. The aim of this study was to determine whether digoxigenin-labeled riboprobes are as sensitive as 35S-labeled probes to detect changes in type I and IV procollagen expression in an animal model of rat gastric ulcer. Both labeling and detection methods yielded similar results, with a superimposable signal distribution in the specimens. High levels of procollagen type I and IV transcripts were observed in spindle-shaped cells, presumably fibroblasts or myofibroblasts, localized in the ulcer base and rim. The increased expression of these collagen types suggests a remarkable upregulation of collagen expression during the healing of gastric ulcers. Liver tissue adhering to perforated ulcers displayed signals related to non-parenchymal cells, with hepatocytes demonstrating no detectable transcripts of type I or IV collagen genes. Due to the identical pattern of signal distribution by both hybridization techniques it is concluded that non-radioactive in situ hybridization is of value in monitoring highly expressed genes and yields results similar to those achieved with radioactive probes. In these cases, non-radioactive techniques are preferable because they are performed more rapidly and do not require handling of isotopes.

Detection of transforming growth factor beta 1 mRNA in cerebrospinal fluid cells of patients with meningitis by non-radioactive in situ hybridization

Meningitis is a serious disease mostly caused by viral or bacterial infections. In complicated cases it may lead to brain damage and death. The infection and cell damage result in a cellular and immunological response. Following this, a high secretion of cytokines can be expected. Cytokines, especially tumour necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1), promote the inflammatory reactions in the subarachnoid space. Transforming growth factor beta 1 (TGF-beta 1) has antagonistic effects on TNF-alpha and IL-1-mediated processes. Therefore, it suppresses inflammatory reactions. To observe the expression of TGF-beta 1 in transcellular signalling in the inflammatory processes of meningitis, we investigated TGF-beta 1 mRNA in cells in the cerebrospinal fluid of three patients with meningitis by non-radioactive in situ hybridization. All patients fulfilled the usual clinical criteria of meningitis. In one case Neisseria menigitidis could be identified as the pathogenic agent. In the remainder, no agent could be isolated. In all cytological preparations of the cerebrospinal fluid of these patients a high level of TGF-beta 1 mRNA was detectable in the cell populations. It was possible to distinguish between the different cell types of the cerebrospinal fluid and to attach the mRNA expression to them. On the one hand, this makes it possible to investigate pathogenesis and defence mechanisms in bacterial and aseptic meningitis on a cellular level; on the other hand, it may open new perspectives in the control of disease development, prognosis, diagnosis and supporting therapy.

Regulation of tumor necrosis factor-alpha-mRNA synthesis and distribution of tumor necrosis factor-alpha-mRNA synthesizing cells in rat liver during experimental endotoxemia

Stimulated liver macrophages (Kupffer cells) are known to release a variety of inflammation-related substances, e.g. cytokines, prostanoids, and reactive oxygen intermediates. For instance, exposure of Kupffer cells in vitro to lipopolysaccharide (endotoxin) leads to a strongly enhanced synthesis of the mRNA for tumor necrosis factor-alpha, the release of the mature protein into culture media. These events are influenced by prostanoids and corticoid hormones. Kupffer cells are thought to be the only source of tumor necrosis factor-alpha within the hepatic sinusoid, but neither this cell specificity nor the regulatory influence of glucocorticoids or prostanoids has been confirmed in the intact organ. Using non-radioactive in situ hybridization, it was possible to obtain specific signals for tumor necrosis factor-alpha-mRNA in individual Kupffer cells uniformly distributed (as compared to Kupffer cells detected by immunohistochemistry) throughout the liver. Kupffer cells were the only cells in the hepatic sinusoids of lipopolysaccharide-perfused livers to express mRNA for tumor necrosis factor-alpha. Simultaneous addition of endotoxin plus dexamethasone and endotoxin and prostaglandin E2 completely suppressed the synthesis of this mRNA. Unexpectedly, the presence of mRNA for tumor necrosis factor-alpha was also detected in the intrahepatic bile duct epithelium of lipopolysaccharide-perfused livers. It is known that biologically active endotoxin is secreted via the bile ducts. These results seem to indicate that bile duct epithelium responds to inflammatory agents with synthesis of tumor necrosis factor-alpha-mRNA. One must also consider new functional aspects of bile duct epithelium in chronic inflammatory diseases, e.g. primary biliary cirrhosis, chronic sclerosing cholangitis or graft-versus-host disease.

Localization of collagen types I, II, and III mRNAs in human heterotopic ossification by non-radioactive in situ hybridization

Heterotopic ossification is a metabolically active process which shares several properties of orthotopic bone formation and, therefore, represents an excellent model for the investigation of matrix components. A novel tool for studying the ossifying process at the level of transcription is the technique of non-radioactive in situ hybridization. Using digoxigenin labeled cDNA probes we investigated the distribution patterns of types I, II and III collagen mRNAs in heterotopic ossification of pressure sores of paraplegic patients. The three collagen mRNAs exhibited substantially divergent distribution patterns. Type I (alpha 1) collagen mRNA was predominantly detectable in preosteoblasts, prechondroblasts and chondrocytes of the ossification zone. Type II (alpha 1) collagen mRNA was nearly exclusively found in cells of the chondrogenic lineage. Type III (alpha 1) collagen mRNA was detectable at low levels in soft tissue, but was strongly expressed by prechondroblasts and chondrocytes of heterotopic cartilage. Our in situ hybridization experiments provide evidence that chondrogenic cells in heterotopic ossification show a phenotypic alteration in collagen type expression. These results indicate that chondrocytes of heterotopic cartilage show a co-expression of types I (alpha 1), II (alpha 1) and III (alpha 1) collagen mRNAs.