Abstract
BackgroundIn physiologic and pathologic conditions of the central nervous system (CNS), astrocytes are a double-edged sword. They not only support neuronal homeostasis but also contribute to increases in neuronal demise. A large body of experimental evidence has shown that impaired astrocytes play crucial roles in the pathologic process of cerebral ischemia; therefore, astrocytes may represent a breakthrough target for neuroprotective therapeutic strategies. Agmatine, an endogenous polyamine catalyzed from L-arginine by arginine decarboxylase (ADC), is a neuromodulator and it protects neurons/glia against various injuries.ResultsIn this investigation, agmatine-producing mouse cortical astrocytes were developed through transduction of the human ADC gene. Cells were exposed to oxygen-glucose deprivation (OGD) and restored to a normoxic glucose-supplied condition. Intracellular levels of agmatine were measured by high performance liquid chromatography. Cell viability was evaluated by Hoechest/propidium iodide nuclear staining and lactate dehydrogenase assay. Expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase s (MMPs) were assessed by a reverse transcription polymerase chain reaction, Western immunoblots, and immunofluorescence. We confirmed that ADC gene-expressed astrocytes produce a great amount of agmatine. These cells were highly resistant to not only OGD but also restoration, which mimicked ischemia-reperfusion injury in vivo. The neuroprotective effects of ADC seemed to be related to its ability to attenuate expression of iNOS and MMPs.ConclusionOur findings imply that astrocytes can be reinforced against oxidative stress by endogenous agmatine production through ADC gene transduction. The results of this study provide new insights that may lead to novel therapeutic approaches to reduce cerebral ischemic injuries.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2202-15-99) contains supplementary material, which is available to authorized users.
Highlights
In physiologic and pathologic conditions of the central nervous system (CNS), astrocytes are a double-edged sword
The SV40 early promoter (PSV40e) controls expression of the neomycin resistance gene (Neor), which allows antibiotic selection in eukaryotic cells. (B) Genetic confirmation by restriction analysis: Lane 1, size marker; Lane 2, restriction enzyme digestion using EcoRI and XhoI; Lane 3, control human arginine decarboxylase (hADC) pLXSN. (C) RNA levels of hADC were verified by RT-polymerase chain reaction (PCR) in PT67 cells and mouse cortical astrocytes (Astro) after hADC pLXSN infection. (D) Expression of hADC was validated by immunocytochemistry in hADC pLXSN-infected astrocytes
We focused on cortical astrocytes, which have recently came to the forefront due to their suspected roles in many CNS injuries, including cerebral ischemia [2,3]
Summary
In physiologic and pathologic conditions of the central nervous system (CNS), astrocytes are a double-edged sword. An endogenous polyamine derived from L-arginine by arginine decarboxylase (ADC), is naturally found in the mammalian central nervous system (CNS) and acts as a multifunctional neuromodulator [5,6,7] It is packed into synaptic vesicles and released from synaptosomes by neuronal depolarization [8,9]. Agmatine can stimulate α2-adrenergic and imidazoline receptors [10,11], block the N-methyl-D-aspartic acid (NMDA) receptor and voltage-gated calcium channel [12,13], and inhibit inducible/neuronal nitric oxide synthases (iNOS/nNOS) [14,15] Through these kinds of intracellular signaling, agmatine shows various antineurotoxic, anticonvulsant, antipsychotic, antidepressant, anxiolytic, and antinociceptive neuroprotective effects [7,16]. Agmatine rescues glial cells, as well as cortical neurons, from oxidative stress in vitro and in vivo [17,21,22]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
