Recombinant arginine deiminase reduces inducible nitric oxide synthase iNOS-mediated neurotoxicity in a coculture of neurons and microglia
Journal
Journal of Neuroscience Research
Journal Volume
86
Journal Issue
13
Pages
2963-2972
Date Issued
2008
Author(s)
Abstract
Modulation of nitric oxide (NO) production is considered a promising approach to therapy of diseases involving excessive inducible nitric oxide synthase (iNOS) expression, such as certain neuronal diseases. Recombinant arginine deiminase (rADI, EC3.5.3.6) catalyzes the conversion of L-arginine (L-arg), the sole substrate of NOS for NO production, to L-citrulline (L-cit) and ammonia. To understand the effect of the depletion of L-arg by rADI on NO concentration and neuroprotection, a direct coculture of neuron SHSY5Y cells and microglia BV2 cells treated with lipopolysaccharide (LPS) and interferon-g (IFN-g) was used as a model of iNOS induction. The results showed that rADI preserved cell viability (4-fold higher compared with the cells treated with LPS/IFN-γ only) by the MTT assay, corresponding with the results of neuronal viability by neuron-specific immunostaining assay. NO production (mean ± SD) decreased from 67.0 ± 1.3 to 19.5 ± 5.5 μm after a 2-day treatment of rADI by the Griess assay; meanwhile, induction of iNOS protein expression by rADI was observed. In addition, rADI substantially preserved the neuronal function of dopamine uptake in the coculture. The replenishment of L-arg in the coculture eliminated the neuroprotective and NO-suppressive effects of rADI in the coculture, indicating that L-arg played a crucial role in the effects of rADI. These results highlight the important role of L-arg in the neuron-microglia coculture in excessive induction of iNOS. Regulation of L-arg by ADI demonstrated that rADI has a potentially therapeutic role in iNOS-related neuronal diseases. ? 2008 Wiley-Liss, Inc.
Subjects
Arginine deiminase; Coculture; iNOS; Neuroprotection; Nitric oxide
SDGs
Other Subjects
3 (4,5 dimethyl 2 thiazolyl) 2,5 diphenyltetrazolium bromide; arginine; arginine deiminase; dopamine; gamma interferon; inducible nitric oxide synthase; lipopolysaccharide; animal cell; article; brain disease; brain nerve cell; cell viability; coculture; concentration (parameters); controlled study; dopamine uptake; enzyme induction; human; human cell; immunohistochemistry; microglia; mouse; neuroprotection; neurotoxicity; nonhuman; priority journal; protein depletion; protein expression; protein function; regulatory mechanism; Arginine; Blotting, Western; Cell Line; Cell Survival; Coculture Techniques; Flow Cytometry; Humans; Hydrolases; Immunohistochemistry; Interferon-gamma; Lipopolysaccharides; Microglia; Neurons; Neuroprotective Agents; Neurotoxins; Nitric Oxide; Nitric Oxide Synthase Type II; Recombinant Proteins
Type
journal article