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Biomedical subjects

J M Clements

Publications and source records attributed to J M Clements.

At least 19 recordsLinked to original sources
PubMed2001

Expression of specific matrix metalloproteinases in inflammatory myopathies.

The family of matrix metalloproteinases (MMPs) comprises endopeptidases that are capable of degrading all extracellular matrix components. Given these actions, it is conceivable that MMPs may play a pathogenic role in inflammatory myopathies. These immune-mediated disorders are characterized by the invasion of mononuclear phagocytes and T lymphocytes and the loss of muscle fibres. We examined whether specific MMPs and their natural inhibitors (tissue inhibitors of metalloproteinases; TIMPs) are expressed in muscle during acute inflammatory attacks by studying muscle biopsies obtained from patients diagnosed as having polymyositis, dermatomyositis, sporadic inclusion body myositis and, for comparison, from cases of various muscular dystrophies. Quantitative polymerase chain reaction analysis revealed significantly elevated mRNA expression of interstitial collagenase (MMP-1) and gelatinase B (MMP-9) in polymyositis and dermatomyositis and to a lesser extent in inclusion body myositis, whereas the level of expression of TIMPs remained unchanged in comparison with controls. Increased mRNA levels were associated with enhanced enzyme expression, as determined by immunoblotting, gelatin zymography and in situ zymography. Immunohistochemically, MMP-1 could be localized around the sarcolemma of diseased muscle fibres and to cells resembling fibroblasts, whereas MMP-9 seemed to be expressed primarily by invading T lymphocytes. Raised levels of MMPs could not be detected in the sera of affected patients, emphasizing the crucial action of MMPs in the inflamed muscle. Our results imply a pathogenic role for specific MMPs in the genesis of inflammatory myopathies, and open new strategies for therapeutic intervention.

Adult↗
PubMed2001

Inhibition of matrix metalloproteinases and tumour necrosis factor alpha converting enzyme as adjuvant therapy in pneumococcal meningitis.

Matrix metalloproteinases (MMPs) and tumour necrosis factor alpha (TNF-alpha) converting enzyme (TACE) contribute synergistically to the pathophysiology of bacterial meningitis. TACE proteolytically releases several cell-surface proteins, including the proinflammatory cytokine TNF-alpha and its receptors. TNF-alpha in turn stimulates cells to produce active MMPs, which facilitate leucocyte extravasation and brain oedema by degradation of extracellular matrix components. In the present time-course studies of pneumococcal meningitis in infant rats, MMP-8 and -9 were 100- to 1000-fold transcriptionally upregulated, both in CSF cells and in brain tissue. Concentrations of TNF-alpha and MMP-9 in CSF peaked 12 h after infection and were closely correlated. Treatment with BB-1101 (15 mg/kg subcutaneously, twice daily), a hydroxamic acid-based inhibitor of MMP and TACE, downregulated the CSF concentration of TNF-alpha and decreased the incidences of seizures and mortality. Therapy with BB-1101, together with antibiotics, attenuated neuronal necrosis in the cortex and apoptosis in the hippocampus when given as a pretreatment at the time of infection and also when administration was started 18 h after infection. Functionally, the neuroprotective effect of BB-1101 preserved learning performance of rats assessed 3 weeks after the disease had been cured. Thus, combined inhibition of MMP and TACE offers a novel therapeutic strategy to prevent brain injury and neurological sequelae in bacterial meningitis.

ADAM Proteins↗
PubMed2001

Antibiotic activity and characterization of BB-3497, a novel peptide deformylase inhibitor.

Peptide deformylase (PDF) is an essential bacterial metalloenzyme which deformylates the N-formylmethionine of newly synthesized polypeptides and as such represents a novel target for antibacterial chemotherapy. To identify novel PDF inhibitors, we screened a metalloenzyme inhibitor library and identified an N-formyl-hydroxylamine derivative, BB-3497, and a related natural hydroxamic acid antibiotic, actinonin, as potent and selective inhibitors of PDF. To elucidate the interactions that contribute to the binding affinity of these inhibitors, we determined the crystal structures of BB-3497 and actinonin bound to Escherichia coli PDF at resolutions of 2.1 and 1.75 A, respectively. In both complexes, the active-site metal atom was pentacoordinated by the side chains of Cys 90, His 132, and His 136 and the two oxygen atoms of N-formyl-hydroxylamine or hydroxamate. BB-3497 had activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis, and activity against some gram-negative bacteria. Time-kill analysis showed that the mode of action of BB-3497 was primarily bacteriostatic. The mechanism of resistance was via mutations within the formyltransferase gene, as previously described for actinonin. While actinonin and its derivatives have not been used clinically because of their poor pharmacokinetic properties, BB-3497 was shown to be orally bioavailable. A single oral dose of BB-3497 given 1 h after intraperitoneal injection of S. aureus Smith or methicillin-resistant S. aureus protected mice from infection with median effective doses of 8 and 14 mg/kg of body weight, respectively. These data validate PDF as a novel target for the design of a new generation of antibacterial agents.

Amidohydrolases↗
PubMed1999

The matrix metalloproteinase inhibitor BB-1101 prevents experimental autoimmune uveoretinitis (EAU).

EAU is characterized by breakdown of the blood-retinal barrier and extravasation of leucocytes into retinal tissue leading to destruction of photoreceptor cells. Matrix metalloproteinases (MMP) have been implicated in trafficking of cells into tissues, but their role in inflammatory eye disease is unclear. A synthetic MMP inhibitor, BB-1101, was administered subcutaneously, from either day 0 or day 7, to Lewis rats challenged with bovine S-antigen to induce EAU. When given up to day 14, BB-1101 reduced the incidence of disease and delayed the day of onset of clinical disease. When administered from day 7 until day 21, EAU was completely abrogated. A quantitative polymerase chain reaction (PCR) assay showed an increase of both matrilysin (MMP-7), neutrophil collagenase (MMP-8) and macrophage metalloproteinase (MMP-12) in retinas from EAU animals compared with naive controls. These enzymes are produced by activated leucocytes and act on components of the basement membrane. These results therefore implicate these MMP as integral to the development of pathology in EAU.

Animals↗
PubMed1999

Differential expression of matrix metalloproteinases in bacterial meningitis.

Matrix metalloproteinases (MMPs) are implicated in the pathogenesis of various inflammatory diseases of the central nervous system. Evidence is accumulating that gelatinase B (MMP-9) might be involved in the pathogenesis of meningitis, but the spectrum of different MMPs involved in the inflammatory reaction of this disease has not been determined. We investigated the temporal and spatial mRNA expression pattern of gelatinase B in experimental meningococcal meningitis in rats. In contrast to controls, increased mRNA levels with peak values 6 h after injection with menigococci were found in brain specimens of the animals. Elevated MMP-9 mRNA expression was accompanied by enhanced proteolytic activity, as demonstrated by gelatin zymography, and positive immunoreactivity. The mRNA expression pattern of six other MMPs was investigated. Collagenase-3 and stromelysin-1 mRNAs were also found to be upregulated. In contrast, mRNA levels for gelatinase A, matrilysin, stromelysin-2 and stromelysin-3 remained unchanged. As evidenced by significantly increased intracranial pressure and by leakage of intravenously injected Evans blue through the blood vessel walls into the brain parenchyma, the animals injected with meningococci revealed signs of blood-brain barrier disruption. Augmented proteolytic activity of MMP-9 could also be demonstrated in CSF samples obtained from patients with bacterial meningitis, underlining the clinical relevance of our experimental findings. Our data indicate that gelatinase B, collagenase-3 and stromelysin-1 are selectively upregulated in bacterial meningitis and thus may contribute to the pathogenesis of this infectious disease of the central nervous system.

Animals↗
PubMed1998

Matrix metalloproteinase expression in an experimentally-induced DTH model of multiple sclerosis in the rat CNS.

In an experimentally-induced DTH model of MS, we examined mRNA and protein expression of a range of MMPs and of TNFalpha to establish the contribution that individual MMPs might make to the pathogenesis. In control rat brain, mRNA for all of the MMPs examined was detectable. However, by immunohistochemistry, only MMP-2 could be detected. In the DTH lesions, significant increases in the level of mRNA expression were observed for MMP-7, MMP-8, MMP-12, and TNFalpha. Where expression of MMP mRNA was increased, there was a corresponding increase in protein expression detected by immunohistochemistry. To determine whether the upregulated MMPs could invoke destructive events in the CNS, highly purified activated MMP-7, MMP-8, and MMP-9 were stereotaxically injected into the brain parenchyma. All provoked recruitment of leukocytes and BBB breakdown. In addition, MMPs 7 and 9 induced loss of myelin staining. In conclusion, specific MMPs are upregulated in DTH lesions; for the most part, measurement of mRNA was a predictor of increased protein expression. From our injections of MMPs, it is clear that the upregulated MMPs in the DTH lesions could participate in the disruption of the BBB, leukocyte recruitment, and tissue damage.

Animals↗
PubMed1998

Matrix metalloproteinases MMP-9 and MMP-7 are expressed in experimental autoimmune neuritis and the Guillain-Barré syndrome.

Matrix metalloproteinases (MMPs) are a family of enzymes that may be implicated in the pathogenesis of inflammatory demyelinating disorders such as multiple sclerosis. The present study investigated the expression of 92-kd gelatinase (MMP-9) and five other MMPs in sciatic nerve from Lewis rats with autoimmune experimental neuritis (EAN), an experimental model of the Guillain-Barré syndrome (GBS). Quantitative polymerase chain reaction analysis revealed an up-regulation of MMP-9 mRNA with peak levels concurrent with maximal disease severity. Increased mRNA expression was associated with enhanced enzyme activity, as detected by gelatin zymography. Immunohistochemically, MMP-9 could be localized primarily around blood vessels within the epineurium and endoneurium in diseased but not normal sciatic nerve. Among all other MMPs investigated, mRNA levels of matrilysin (MMP-7) were found to be up-regulated at the peak of the disorder, remaining at high levels throughout the clinical recovery phase of the disease. To apply these findings to human disease, sural nerve biopsies from GBS patients were examined. By using immunohistochemistry, positive immunoreactivity against MMP-9 and MMP-7 was noted and corroborated by demonstrating augmented mRNA expression in comparison with noninflammatory neuropathies. Furthermore, increased MMP-9 activity was detected by zymography. These findings indicate that 92-kd gelatinase and matrilysin are selectively up-regulated during EAN and expressed in nerves of GBS patients and thus may contribute to the pathogenesis of inflammatory demyelination of the peripheral nervous system.

Animals↗
PubMed1998

Effective treatment of models of multiple sclerosis by matrix metalloproteinase inhibitors.

The proinflammatory Th1 cytokine, tumor necrosis factor-alpha (TNF alpha), the cell death signaling molecule FasL, and several extracellular matrix degrading metalloproteinases have been implicated in the pathogenesis of multiple sclerosis (MS). The latter enzymes, as well as TNF alpha-converting enzyme and FasL-converting enzyme, can be blocked by matrix metalloproteinase inhibitors (MMPIs). In this study, we show that a potent MMPI was clinically effective in an animal model for MS, experimental autoimmune encephalomyelitis (EAE) in the SJL/J mouse. Efficacy was remarkable, as indicated by blocking and reversal of acute disease and reduced number of relapses and diminished mean cumulative disease score in chronic relapsing animals. Also, demyelination and glial scarring were significantly decreased in MMPI-treated mice with chronic relapsing EAE, as was central nervous system gene expression for TNF alpha and fasL. It is interesting that expression of the beneficial cytokine interleukin-4 (IL-4) was increased, and IL-4 was expressed on glial cells. The relevance of these compounds for MS was underscored by their ability to specifically inhibit TNF alpha shedding and cytotoxicity of myelin-autoreactive human cytotoxic CD4+ T-cell clones. This is the first report to show a positive effect by MMPIs on chronic relapsing EAE, its central nervous system cytokine profile, and on TNF alpha shedding by human myelin-autoreactive T cells.

Animals↗
PubMed1998

Matrix metalloproteinase-9 and -7 are regulated in experimental autoimmune encephalomyelitis.

Matrix metalloproteinases (MMPs) comprise a group of proteolytic enzymes that are implicated in the pathogenesis of inflammatory diseases of the nervous system such as multiple sclerosis. However, the exact function and expression pattern of MMPs in the inflamed nervous system are not known. In the present study we investigated the expression of 92-kDa gelatinase (MMP-9) in spinal cord from animals with adoptive transfer experimental autoimmune encephalomyelitis (AT-EAE), using a semiquantitative competitive reverse transcriptase-polymerase chain reaction assay. Increased levels of MMP-9 mRNA were found with peak values at times of maximum disease severity. Increased mRNA expression was associated with enhanced proteolytic activity of this enzyme, as demonstrated by gelatin zymography. Immunohistochemistry revealed immunoreactivity along the meninges, around blood vessels and within the parenchyma, in diseased but not in normal spinal cord. Furthermore, the expression pattern of five other MMPs was investigated. Matrilysin (MMP-7) was also found to be upregulated with maximum mRNA levels at the peak of the disease. In contrast, mRNAs for collagenase-3, 72-kDa gelatinase, and stromelysin-1 and -3 were not changed. Our findings indicate that 92-kDa gelatinase and matrilysin are selectively upregulated during AT-EAE and thus may contribute to the pathogenesis of inflammatory diseases of the CNS.

Animals↗
PubMed1998

Matrix metalloproteinase expression during experimental autoimmune neuritis.

Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome. We have shown recently that BB-1101, a broad-spectrum matrix metalloproteinase (MMP) inhibitor, prevents development of EAN when given from the day of immunization and, more important clinically, reduces disease severity when given from symptom onset. This suggests the involvement of MMP activity in the pathogenesis of EAN. However, the exact function and expression patterns of MMPs in acute inflammation of the PNS have not been investigated. MMP-like enzymes are also involved in the processing of tumour necrosis factor-alpha (TNF-alpha), which has been implicated previously in the pathology associated with EAN. In the present study we investigated the profile of MMP and TNF-alpha expression and their localization in sciatic nerve tissue during EAN, using a semiquantitative competitive reverse transcriptase-coupled polymerase chain reaction and immunohistochemistry. In the normal rat PNS, four of the 10 MMPs studied were constitutively expressed and four MMPs were differentially regulated during EAN. Expression of TNF-alpha was elevated at peak disease severity and localized to Schwann cells, macrophages and endoneurial blood vessels. Expression levels of 92 kDa gelatinase and stromelysin-1 were significantly increased early in the development of EAN and continued to rise, peaking at day 15 coincident with maximum disease severity. Schwann cells and endothelial cells were the main cellular source of these enzymes. Prominent infiltration of inflammatory cells into the sciatic nerve was concordant with a significant increase in the expression levels of matrilysin and macrophage metalloelastase. Both matrilysin and macrophage metalloelastase were detected in invading macrophages, T lymphocytes and resident Schwann cells. The selective upregulation of specific MMPs during EAN and their varied cellular localization suggests that MMPs play a multifactorial role in the aetiology of EAN. Activity of MMPs could participate in the disruption of the blood-nerve barrier, breakdown of the myelin sheath, the release of TNF-alpha, and facilitate leukocyte invasion into the PNS. These observations highlight MMPs as potential targets for therapeutic intervention in acute peripheral neuropathies, such as Guillain-Barré syndrome.

Animals↗
PubMed1997

Association between receptor density, cellular activation, and transformation of adhesive behavior of flowing lymphocytes binding to VCAM-1.

We investigated the ability of purified vascular cell adhesion molecule-1 (VCAM-1), adsorbed on plastic, to capture and immobilize flowing lymphocytes, and the dependence of adhesive behavior on activation of the counter-receptor, alpha 4 beta 1 integrin. This integrin/immunoglobulin interaction bound lymphocytes at a wall shear stress at which the beta 2-integrin family has previously been found ineffective (> 0.1 Pa), and whereas lymphocytes rolled on lower concentrations of VCAM-1 (10 micrograms/ml), they were stationary at high concentrations (100 micrograms/ml). Activation of alpha 4 beta 1 integrin by Mn2+ or by antibody 12G10 or treatment of lymphocytes with phorbol ester caused transformation to stationary adhesion, and increased binding significantly only at the lower concentrations of VCAM-1. We thus hypothesized that formation of a high density of ligand between VCAM-1 and alpha 4 beta 1 integrin actively transformed lymphocyte behavior. This concept was supported by the finding that the proportion of lymphocytes rolling on the higher concentrations of VCAM-1 increased if cells were pretreated with azide to block energy-dependent responses, or if intracellular Ca2+ was chelated. However, not all activation responses were equivalent: only phorbol ester induced marked spreading of immobilized cells, and if pretreatment was prolonged, this agent even reduced the efficiency of initial attachment of flowing lymphocytes. Azide treatment had no effect on transformation to stationary adhesion caused by Mn2+ or activating antibody. Thus, different forms of lymphocyte activation were identifiable: external modification of integrin converted rolling to stationary attachment, did not require ATP, and was reversible; high-density ligand binding induced an energy-dependent signal for conversion from rolling to stationary attachment, but not spreading; and protein kinase C activation promoted stationary attachment and spreading, but not necessarily capture. VCAM-1 is thus a versatile adhesion receptor capable of supporting all stages of leukocyte attachment, i.e. rolling, stationary, and spreading, and of ligand-induced transformation of adhesion, although an additional signal appears necessary to promote lymphocyte spreading and migration.

Animals↗
PubMed1997

Enhanced expression of MMP-7 and MMP-9 in demyelinating multiple sclerosis lesions.

The pathology of multiple sclerosis (MS) is characterised by breakdown of the blood-brain barrier accompanied by infiltration of macrophages and T cells into the central nervous system (CNS). Myelin is degraded and engulfed by the macrophages, producing lesions of demyelination. Some or all of these mechanisms might involve proteinases, and here we have studied the cellular localisation and distribution of two matrix metalloproteinases (MMPs), MMP-7 (matrilysin) and MMP-9 (92-kDa gelatinase), in the normal human CNS and active demyelinating MS lesions. Cryostat sections of CNS samples were immunostained with antisera to MMP-7 and MMP-9. In addition, non-radioactive in situ hybridisation (ISH) was performed using a digoxygenin-labelled riboprobe to detect the expression of MMP-7. MMP-7 immunoreactivity was weakly detected in microglial-like cells in normal brain tissue sections, and was very strong in parenchymal macrophages in active demyelinating MS lesions. This pattern of expression was confirmed using ISH. MMP-7 immunoreactivity was not detected in macrophages in spleen or tonsil indicating that it is specifically induced in infiltrating macrophages in active demyelinating MS lesions. MMP-9 immunoreactivity was detected in a few small blood vessels in normal brain tissue sections, whereas many blood vessels stained positive in CNS tissue sections of active demyelinating MS lesions. The up-regulation of MMPs in MS may contribute to the pathology of the disease.

Adult↗
PubMed1997

Matrix metalloproteinases, tumor necrosis factor and multiple sclerosis: an overview.

The matrix metalloproteinases (MMPs) are a family of at least 14 zinc-dependent enzymes which are known to degrade the protein components of extracellular matrix. In addition, MMPs and related enzymes can also process a number of cell surface cytokines, receptors, and other soluble proteins. In particular we have shown that the release of the pro-inflammatory cytokine, tumor necrosis factor-alpha, from its membrane-bound precursor is an MMP-dependent process. MMPs are expressed by the inflammatory cells which are associated with CNS lesions in animal models of multiple sclerosis (MS) and in tissue from patients with the disease. MMP expression will contribute to the tissue destruction and inflammation in MS. Drugs which inhibit MMP activity are effective in animal models of MS and may prove to be useful therapies in the clinic.

Animals↗
PubMed1997

Matrix metalloproteinase expression during experimental autoimmune encephalomyelitis and effects of a combined matrix metalloproteinase and tumour necrosis factor-alpha inhibitor.

Matrix metalloproteinases (MMPs) are a large family of Zn2+ endopeptidases that are expressed in inflammatory conditions and are capable of degrading connective tissue macromolecules. MMP-like enzymes are also involved in the processing of a variety of cell surface molecules including the pro-inflammatory cytokine TNF-alpha. MMPs and TNF-alpha have both been implicated in the pathology associated with neuro-inflammatory diseases (NIDs), particularly multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). We have shown that BB-1101, a broad spectrum hydroxamic acid-based combined inhibitor of MMP activity and TNF processing, reduces the clinical signs and weight loss in an acute EAE model in Lewis rats. However, little is known about which MMPs are involved in the neuroinflammatory process. In order to determine the optimum inhibitory profile for an MMP inhibitor in the treatment of NID, we investigated the profile of MMP expression and activity during EAE. The development of disease symptoms was associated with a 3-fold increase in MMP activity in the cerebrospinal fluid (CSF), which could be inhibited by treatment with BB-1101, and an increase in 92 kDa gelatinase activity detected by gelatin substrate zymography. Quantitative PCR analysis of normal and EAE spinal cord revealed the expression of at least seven MMPs. Of these, matrilysin showed the most significant change, being elevated over 500 fold with onset of clinical symptoms and peaking at maximum disease severity. Of the other six MMPs detected, 92 kDa gelatinase showed a modest 5 fold increase which peaked at the onset of clinical signs and then declined during the most severe phase of the disease. Matrilysin was localised by immunohistochemistry to the invading macrophages within the inflammatory lesions of the spinal cord. Matrilysin's potent broad spectrum proteolytic activity and its localisation to inflammatory lesions in the CNS suggest this enzyme could be particularly involved in the pathological processes associated with neuro-inflammatory disease.

Animals↗
PubMed1996

Identification of MMP-18, a putative novel human matrix metalloproteinase.

A partial cDNA encoding the 3' end of a putative novel human matrix metalloproteinase (MMP) was identified by sequence similarity searching of databases containing expressed sequence tags. The remaining 5' end of the MMP cDNA was amplified by PCR from human mammary gland cDNA. The predicted protein product displays all the structural features characteristic of the MMP family and has closest identity with MMP-1, -3, -10, and 11. We have provisionally designated this novel MMP as MMP-18. MMP-18 mRNA is expressed in a wide variety of normal human tissues, including mammary gland, placenta, lung, pancreas, ovary, small intestine, spleen, thymus, prostate, testis, colon, and heart, but is not detected in brain, skeletal muscle, kidney, liver, or peripheral blood leucocytes.

Amino Acid Sequence↗
PubMed1996

mRNA sequences influencing translation and the selection of AUG initiator codons in the yeast Saccharomyces cerevisiae.

The secondary structure and sequences influencing the expression and selection of the AUG initiator codon in the yeast Saccharomyces cerevisiae were investigated with two fused genes, which were composed of either the CYC7 or CYC1 leader regions, respectively, linked to the lacZ coding region. In addition, the strains contained the upf1-delta disruption, which stabilized mRNAs that had premature termination codons, resulting in wild-type levels. The following major conclusions were reached by measuring beta-galactosidase activities in yeast strains having integrated single copies of the fused genes with various alterations in the 89 and 38 nucleotide-long untranslated CYC7 and CYC1 leader regions, respectively. The leader region adjacent to the AUG initiator codon was dispensable, but the nucleotide preceding the AUG initiator at position -3 modified the efficiency of translation by less than twofold, exhibiting an order of preference A > G > C > U. Upstream out-of-frame AUG triplets diminished initiation at the normal site, from essentially complete inhibition to approximately 50% inhibition, depending on the position of the upstream AUG triplet and on the context (-3 position nucleotides) of the two AUG triplets. In this regard, complete inhibition occurred when the upstream and downstream AUG triplets were closer together, and when the upstream and downstream AUG triplets had, respectively, optimal and suboptimal contexts. Thus, leaky scanning occurs in yeast, similar to its occurrence in higher eukaryotes. In contrast, termination codons between two AUG triplets causes reinitiation at the downstream AUG in higher eukaryotes, but not generally in yeast. Our results and the results of others with GCN4 mRNA and its derivatives indicate that reinitiation is not a general phenomenon in yeast, and that special sequences are required.

Base Sequence↗
PubMed1996

Quantitation of matrix metalloproteinases in cultured rat astrocytes using the polymerase chain reaction with a multi-competitor cDNA standard.

Matrix metalloproteinases (MMPs) are a family of Zn2+ endopeptidases that are expressed in many inflammatory conditions and that contribute to connective tissue breakdown and the release of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha). There is emerging evidence that MMPs have a role in inflammatory disorders of the central nervous system (CNS) such as multiple sclerosis. However, little is known about the expression of MMPs by inflamed tissue within the CNS or by the glia, neurones, and leucocytes which participate in the inflammatory response. To address this issue we have developed a polymerase chain reaction (PCR)-based method for the quantitation of rat MMP mRNA levels, which we have applied to astrocyte cultures with and without inflammatory stimulation. The technique relies on a competition reaction in which a synthetic standard cDNA is co-amplified with the target cDNA in the same PCR reaction. Standard multi-competitor cDNAs, containing priming sites for nine MMPs, and two housekeeping genes were constructed. We have shown that MMP activity is increased over three-fold in neonatal rat astrocyte cultures following stimulation with lipopolysaccharide (LPS). At the mRNA level, MT-MMP-1, 72 kDa gelatinase, and stromelysin-3 were constitutively expressed and unaffected by LPS treatment, whereas 92 kDa gelatinase, and stromelysin-1 were strongly induced (1,000-fold). Stromelysin-2, rat collagenase, and macrophage metalloelastase were modestly upregulated by LPS treatment. Matrilysin was not expressed. This technique is suitable for quantifying MMP expression in the cells which contribute to inflammation in the CNS and could also be applied directly to tissue samples from animal models of disease.

Animals↗