Author Correction: Amine oxidase 3 is a novel pro-inflammatory marker of oxidative stress in peritoneal endometriosis lesions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Amine oxidase 3 is a novel pro-inflammatory marker of oxidative stress in peritoneal endometriosis lesions.

Endometriosis is a common gynaecological disease of women in reproductive age, and is thought to arise from retrograde menstruation and implantation of endometrial tissue, mostly into the peritoneal cavity. The condition is characterized by a chronic, unresolved inflammatory process thereby contributing to pain as cardinal symptom in endometriosis. Elevated reactive oxygen species (ROS) and oxidative stress have been postulated as factors in endometriosis pathogenesis. We here set out for a systematic study to identify novel mechanisms and pathways relating to oxidative stress in ectopic peritoneal lesions. Using combined proteomic and transcriptomic approaches, we identified novel targets including upregulated pro-oxidative enzymes, such as amine oxidase 3/vascular adhesion protein 1 (AOC3/VAP1) as well as downregulated protective factors, in particular alkenal reductase PTGR1 and methionine sulfoxide reductase. Consistent with an altered ROS landscape, we observed hemoglobin / iron overload, ROS production and lipid peroxidation in ectopic lesions. ROS-derived 4-hydroxy-2-nonenal induced interleukin IL-8 release from monocytes. Notably, AOC3 inhibitors provoked analgesic effects in inflammatory pain models in vivo, suggesting potential translational applicability.

Optimized synthesis of AMPA receptor antagonist ZK 187638 and neurobehavioral activity in a mouse model of neuronal ceroid lipofuscinosis.

Previous structure-activity relationship studies in the search for a potent, noncompetitive alpha-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist led to 2,3-dimethyl-6-phenyl-12H-[1,3]dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine (ZK 187638). However, the first synthesis had some drawbacks regarding reagents, processes, and overall yield, which furthermore decreased when the synthesis was scaled up. Therefore, we now report a new synthetic route for this compound which requires fewer steps and is suited for large-scale production. This compound significantly relieved the symptoms of neuromuscular deficit in mnd mice, a model of neuronal ceroid lipofuscinosis with motor neuron dysfunction. After oral administration, the concentrations of the compound in the brain and spinal cord were about threefold higher than those in the plasma. In summary, this novel AMPA antagonist is accessible through an optimized synthetic route, has good neurobehavioral activity, oral bioavailability, and favorable brain penetration. This opens new possibilities for the treatment of devastating neurological diseases that are mediated by the AMPA receptor.

Extended therapeutic time window after focal cerebral ischemia by non-competitive inhibition of AMPA receptors.

In acute stroke, the therapeutic time window is a critical factor which may have contributed to the failure of several phase III clinical trials with so-called neuroprotective agents. Since cerebral glutamate levels are elevated for many hours in progressing stroke, we investigated the novel AMPA glutamate receptor antagonist ZK 187638 in rodent models of stroke using up to 12 h delays in the start of therapy after permanent occlusion of the middle cerebral artery (MCA). In rats, ZK 187638 reduced total infarct volume by 43% and 33% when therapy was started immediately or with a delay of 6 h, respectively, but no effect was observed after a 12 h delay. Dose-dependent decreases of total infarct volume (up to 42%) were measured in mice given the first injection of ZK 187638 6 h after permanent MCA occlusion. In conclusion, the AMPA receptor antagonist ZK 187638 has a therapeutic time window of at least 6 h after permanent focal cerebral ischemia in rodents.

Glutamate AMPA receptors change in motor neurons of SOD1G93A transgenic mice and their inhibition by a noncompetitive antagonist ameliorates the progression of amytrophic lateral sclerosis-like disease.

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder involving the selective degeneration of motor neurons. In a small proportion of patients, ALS is caused by mutations in copper/zinc superoxide dismutase (SOD1), and mice overexpressing SOD1(G93A) mutant develop a syndrome that closely resembles the human disease. Excitotoxicity mediated by glutamate AMPA receptors has been suggested to be implicated in the selective susceptibility of motor neurons occurring in ALS. In SOD1(G93A) mice, we found that levels of GluR2 AMPA subunit, which plays a pivotal role in the maintenance of calcium impermeability of AMPA receptors, are decreased in spinal motor neurons before symptom onset in concomitance with a modest increase of GluR3 expression, a calcium-permeable AMPA subunit. This effect can result in a higher number of calcium-permeable AMPA receptors on motor neurons of SOD1(G93A) mice, predisposing these cells to be injured by AMPA-mediated glutamate firing. In support of this, we showed that treatment with a new noncompetitive AMPA antagonist, ZK 187638, partially protected motor neurons, improved motor function, and prolonged the survival of SOD1(G93A) mice.

Novel alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonists of 2,3-benzodiazepine type: chemical synthesis, in vitro characterization, and in vivo prevention of acute neurodegeneration.

Under pathophysiological conditions, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor activation is considered to play a key role in several disorders of the central nervous system. In the search for AMPA receptor antagonists, the synthesis and pharmacological characterization of a series of novel compounds that are structurally related to GYKI 52466 (1), a well-known selective noncompetitive AMPA receptor antagonist, was performed. In vitro, 2,3-dimethyl-6-phenyl-12H-[1,3]dioxolo[4,5-h]imidazo[1,2-c][2,3]benzodiazepine (ZK 187638, 14a) antagonized the kainate-induced currents in cultured hippocampal neurons with an IC(50) of 3.4 microM in a noncompetitive fashion. When tested in a clinically predictive rat model of acute ischemic stroke, this noncompetitive AMPA receptor antagonist significantly reduced brain infarction, indicating that it is neuroprotective after permanent focal cerebral ischemia.

Functional characterization and comparison of the outer blood-retina barrier and the blood-brain barrier.

PURPOSE: To determine efflux systems of the outer blood-retina barrier (oBRB) and compare the oBRB with the blood-brain barrier (BBB). METHODS: Porcine oBRB structure and transport characteristics of freshly dissected intact tissue sheets were investigated with scanning electron microscopy, immunocytochemistry, vital dye labeling, and pharmacological agents, using HPLC/mass spectrometry. To compare drug permeation across the oBRB and the BBB, three different systems were used: (1) oBRB tissue sheets in a two-chamber device in vitro; (2) an in vitro BBB model composed of purified astrocytes and brain capillary endothelial cells on transfilter membranes; and (3) an in vivo model based on the brain-plasma ratio of drugs in mice. RESULTS: Efflux pumps (multidrug resistance protein [P-gp] and multidrug resistance-associated protein [MRP]) were demonstrated by antibody staining. Side-specific application of three P-gp and MRP substrates and selective transport inhibition suggested that both membrane proteins were preferentially located on the choroidal side of the oBRB. Therefore, the efflux was directed toward the blood, as in the BBB. To relate the transport characteristics of the oBRB to the BBB, up to nine different test compounds were used. The ranking of the permeability coefficients (P(e)) and the brain-plasma ratios of test compounds indicated that the oBRB has barrier and carrier features similar to those of the BBB in vitro and in vivo. CONCLUSIONS: Despite the fact that epithelial oBRB and endothelial BBB have developed as separate entities with many site-specific functions, their transport and permeation characteristics display surprising similarities, that include the polarized expression of the two major efflux pumps P-gp and MRP.