Discovery of GSK2795039, a Novel Small Molecule NADPH Oxidase 2 Inhibitor.

Aims: The NADPH oxidase (NOX) family of enzymes catalyzes the formation of reactive oxygen species (ROS). NOX enzymes not only have a key role in a variety of physiological processes but also contribute to oxidative stress in certain disease states. To date, while numerous small molecule inhibitors have been reported (in particular for NOX2), none have demonstrated inhibitory activity in vivo.

Role of calcium independent phospholipase A2 in maintaining mitochondrial membrane potential and preventing excessive exocytosis in PC12 cells.

This study was carried out to elucidate the effects of calcium independent phospholipase A(2) (iPLA(2)) on mitochondrial function and exocytosis in neuroendocrine cells. iPLA(2) mRNA and protein were detected in cell lysates and mitochondria from PC12 cells. Treatment of cells with the iPLA(2) inhibitor, bromoenol lactone (BEL), resulted in reduction in the mitochondrial membrane potential.

Effects of cholesterol oxidation products on exocytosis.

Increase in levels of oxysterols or cholesterol oxidation products have been detected in brain areas undergoing neuroinflammation after excitotoxic injury, and the present study was carried out to elucidate possible effects of these products on exocytosis in rat pheochromocytoma-12 (PC12) cells. An increase in vesicle fusion with the cell membrane indicating exocytosis was observed by total internal reflection microscopy (TIRFM), and confirmed by capacitance measurements, after addition of 7 ketocholesterol, 24 hydroxycholesterol or cholesterol 5, 6 beta epoxide. 7 ketocholesterol induced exocytosis was attenuated by pretreatment with a disruptor of cholesterol-rich domains or "lipid rafts", methyl-beta-cyclodextrin (MbetaCD) as demonstrated by capacitance and amperometry measurements of neurotransmitter release.

Expression profile of multiple secretory phospholipase A(2) isoforms in the rat CNS: enriched expression of sPLA(2)-IIA in brainstem and spinal cord.

Phospholipases A(2) (PLA(2)) are enzymes which cleave the sn-2 ester bond in membrane phospholipids to release free fatty acids and lysophospholipids. The present study aimed to elucidate the expression profile of multiple secretory phospholipase A(2) (sPLA(2)) isoforms in the normal rat CNS with focus on sPLA(2)-IIA in the brainstem and spinal cord. Quantitative RT-PCR analysis showed that sPLA(2)-IB expression was low throughout the CNS, sPLA(2)-IIA expression was high in the brainstem and spinal cord, sPLA(2)-IIC expression was high in the cerebral neocortex, hippocampus and thalamus/hypothalamus, sPLA(2)-V expression was high in the olfactory bulb and cerebellum, and sPLA(2)-X was expressed at very low levels in the normal CNS.

Differential effects of lysophospholipids on exocytosis in rat PC12 cells.

Secretory phospholipase A2 (sPLA2) activity is present in the CNS and the sPLA2-IIA isoform has been shown to induce exocytosis in cultured hippocampal neurons. However, little is known about possible contributions of various lysophospholipid species to exocytosis in neuroendocrine cells. This study was therefore carried out to examine the effects of several lysophospholipid species on exocytosis on rat pheochromocytoma-12 (PC12) cells.