| 1. |
- Efsen, Eva, et al.
(författare)
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Ramiprilate Inhibits Functional Matrix Metalloproteinase Activity in Crohns Disease Fistulas
- 2011
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Ingår i: Basic & Clinical Pharmacology & Toxicology. - : WILEY-BLACKWELL, COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA. - 1742-7835 .- 1742-7843. ; 109:3, s. 208-216
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Tidskriftsartikel (refereegranskat)abstract
- Increased expression of matrix metalloproteinase (MMP)-2, -3 and -9 has been demonstrated in Crohns disease fistulas, but it is unknown whether these enzymes are biologically active and represent a therapeutic target. Therefore, we investigated the proteolytic activity of MMPs in fistula tissue and examined the effect of inhibitors, including clinically available drugs that beside their main action also suppress MMPs. Fistula specimens were obtained by surgical excision from 22 patients with Crohns disease and from 10 patients with fistulas resulting from other causes. Colonic endoscopic biopsies from six controls were also included. Total functional MMP activity was measured by a high-pressure liquid chromatography (HPLC)-based, fluorogenic MMP-substrate cleavage assay, and the specific activity of MMP-2, -3 and -9 by the MMP Biotrak Activity Assay. The MMP inhibitors comprised ethylene-diamine-tetraacetic acid (EDTA), the synthetic broad-spectrum inhibitor, GM6001, the angiotensin-converting enzyme (ACE) inhibitor, ramiprilate, and the tetracycline, doxycycline. In Crohns disease fistulas, about 50% of the total protease activity was attributable to MMP activity. The average total MMP activity was significantly higher (about 3.5-times) in Crohns fistulas (471 FU/mu g protein, range 49-2661) compared with non-Crohns fistulas [134 FU/mu g protein, range 0-495, (p andlt; 0.05)] and normal colon [153 FU/mu g protein, range 77-243, (p andlt; 0.01)]. MMP-3 activity was increased in Crohns fistulas (1.4 ng/ml, range 0-9.83) compared with non-Crohns fistulas, [0.32 ng/ml, range 0-2.66, (p andlt; 0.02)]. The same applied to MMP-9 activity [0.64 ng/ml, range 0-5.66 and 0.17 ng/ml, range 0-1.1, respectively (p andlt; 0.04)]. Ramiprilate significantly decreased the average total MMP activity level by 42% and suppressed the specific MMP-3 activity by 72%, which is comparable to the effect of GM6001 (87%). Moreover, MMP-9 activity was completely blunted by ramiprilate. Doxycycline had no effect on MMP activity. Increased functional MMP activity, notably MMP-3 and -9, is present in Crohns fistulas and may be inhibited by ramiprilate, a widely available ACE inhibitor.
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| 2. |
- Larsson, Christer, et al.
(författare)
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Activation of protein kinase C in permeabilized human neuroblastoma SH-SY5Y cells
- 1992
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 59:2, s. 644-651
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Tidskriftsartikel (refereegranskat)abstract
- The activation of protein kinase C was investigated in digitonin-permeabilized human neuroblastoma SH-SY5Y cells by measuring the phosphorylation of the specific protein kinase C substrate myelin basic protein4-14. The phosphorylation was inhibited by the protein kinase C inhibitory peptide PKC19-36 and was associated to a translocation of the enzyme to the membrane fractions of the SH-SY5Y cells. 1,2-Dioctanoyl-sn-glycerol had no effect on protein kinase C activity unless the calcium concentration was raised to concentrations found in stimulated cells (above 100 nM). Calcium in the absence of other activators did not stimulate protein kinase C. Phorbol 12-myristate 13-acetate was not dependent on calcium for the activation or the translocation of protein kinase C. The induced activation was sustained for 10 min, and thereafter only a small net phosphorylation of the substrate could be detected. Calcium or dioctanoylglycerol, when applied alone, only caused a minor translocation, whereas in combination a marked translocation was observed. Arachidonic acid (10 microM) enhanced protein kinase C activity in the presence of submaximal concentrations of calcium and dioctanoylglycerol. Quinacrine and p-bromophenacyl bromide did not inhibit calcium- and dioctanoylglycerol-induced protein kinase C activity at concentrations which are considered to be sufficient for phospholipase A2 inhibition.
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