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Botulinum neurotoxin serotype A (BoNT/A) is a proteolytic enzyme that induces muscle paralysis. It is a cause of food poisoning, a potential bioterrorist threat and, in low doses an emerging pharmaceutical product. No effective treatment is currently available for BoNT intoxication. Previously we developed a BoNT/A light chain enzyme assay using a peptide substrate based on the SNAP-25 protein target, with HPLC separation and UV detection of assay products, and applied the method to screen combinatorial peptide libraries for inhibitory activity to BoNT/A. We now report on development of a capillary electrophoresis laser-induced fluorescence (CE-LIF) method for measuring BoNT/A activity. The enzyme assay products were labeled with CBQCA dye followed by CE separation on a bare fused silica column in a HEPES-based buffer and LIF detection. All assay products were separated in CE within 8 min compared to incomplete separation of assay products within 1h by HPLC. The labeled products showed linear dependence of intensity versus concentration, and quantitative mole-fraction assignments. We used the CE-LIF method to screen combinatorial peptide libraries for potential modulating effects on BoNT/A peptidase activity. With some of the libraries, peptides co-migrated with assay products and interfered with quantitation. In such cases, interference was reduced by substituting sodium dodecyl sulfate (SDS) for Tween-20 in the running buffer. Separation in the capillaries then occurred by micellar electrokinetic chromatography (MEKC). The CE-LIF method is quick and lends itself to high-throughput or microfluidic formats.

Matrix metalloproteinases (MMPs) have been implicated as important factors in gliomas since they may both facilitate invasion into the surrounding brain and participate in neovascularization. We have tested the hypothesis that deregulated expression of gelatinase-A or B, or an activator of gelatinase-A, MT1-MMP, may contribute directly to human gliomas by quantifying the expression of these MMPs in 46 brain tumour specimens and seven control tissues. Quantitative RT-PCR and gelatin zymography showed that gelatinase-A in glioma specimens was higher than in normal tissue; these were significantly elevated in low grade gliomas and remained elevated in GBMs. Gelatinase-B transcript and activity levels were also higher than in normal brain and more strongly correlated with tumour grade. We did not see a close relationship between the levels of expression of MT1-MMP mRNA and amounts of activated gelatinase-A. In situ hybridization localized gelatinase-A and MT1-MMP transcripts to normal neuronal and glia, malignant glioma cells and blood vessels. In contrast, gelatinase-B showed a more restricted pattern of expression; it was strongly expressed in blood vessels at proliferating margins, as well as tumour cells in some cases. These data suggest that gelatinase-A, -B and MT1-MMP are important in the pathophysiology of human gliomas. The primary role of gelatinase-B may lie in remodelling associated with neovascularization, whereas gelatinase-A and MT1-MMP may be involved in both glial invasion and angiogenesis.

Purpose: Extra-neural metastases from glioblastoma multiforme (GBM) are rare. Because gelatinases-A and -B have been implicated in tumor invasion/metastasis in non-neural tumors, we compared the expression of gelatinase-A and -B in 2 patients (both had a prior craniotomy performed) with extraneural metastases from GBM to expression levels in 24 other gliomas; 15 non-metastatic GBMs, 9 other lower grade gliomas, and 7 normal brain tissues., Methods: The intracerebral tumor from both patients, patient # 1's extraneural metastases, 24 other gliomas, 1 sample of reactive astrocytes and 7 normal brain tissues were studied using gelatin zymography. The active form of gelatinases was confirmed by co-migration after activation with APMA., Results: Expression of the latent form of gelatinase-A correlated with glioma grade (r = 0.486; p = 0.0053). Active gelatinase-A was found only in the 2 GBMs with extraneural metastases and patient # 1's cervical metastases. In contrast, latent gelatinase-B levels correlated more strongly with histologic grade (r = 0.577; p = 0.0009) (higher levels with higher grades). Very high levels of gelatinase-B were seen in both GBMs with extraneural metastases, a cervical extraneural metastases, and 2 GBMs without metastases., Conclusions: We observed that gelatinases-A and -B are present in most gliomas but we found active gelatinase-A only in the GBMs with extraneural metastases suggesting that the active form of this enzyme may determine the metastatic potential of GBMs. We propose that high levels of gelatinolytic activities are associated with intracerebral invasion and rarely, metastases of GBMs.

Tissue inhibitors of metalloproteinases (TIMPs) are secreted proteins that block the activities of the extracellular matrix (ECM)-degrading metalloproteinases (MMPs). As key determinants of ECM integrity and turnover, TIMPs are involved in the establishment and maintenance of tissue architecture and may indirectly influence ECM-dependent cells signaling. In addition, TIMPs exert both positive and negative effects on cell growth through mechanisms that are independent of MMP inhibition. The three members of the mammalian TIMP family differ in structure, biochemical properties and expression, suggesting that they have distinct physiological roles. Here, we review recent advances in our understanding of TIMP protein function and gene regulation. We discuss the potential relevance of MMPs and TIMPs in obesity with regard to effects on the processing of tumor necrosis factor-alpha.

We have cloned, expressed, and partially purified a naturally occurring, truncated, soluble form of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha subunit to investigate its biochemical and biologic properties. The soluble receptor species lacks the transmembrane and cytoplasmic domains that are presumably removed from the intact receptor cDNA by a mechanism of alternative splicing. The resulting soluble 55- to 60-kD glycosylated receptor species binds GM-CSF with a dissociation constant (kd) of 3.8 nmol/L. The soluble GM-CSF receptor successfully competes for GM-CSF binding not only with the transmembrane-anchored GM-CSF receptor alpha subunit but also with the native oligomeric high-affinity receptor complex. In addition, in human bone marrow colony-forming assays, the soluble GM-CSF receptor species can antagonize the activity of GM-CSF. Our data suggest that the soluble GM-CSF receptor may be capable of acting in vivo as a modulator of the biologic activity of GM-CSF.