Enhanced expression of glycine N‐methyltransferase by adenovirus‐mediated gene transfer in CNS culture is neuroprotective

Abstract

Glycine N-methyltransferase (GNMT) is the most abundant hepatic methyltransferase and plays important roles in regulating methyl group metabolism. In the central nervous system, GNMT expression is low and its function has not been revealed. The present study examines the effect of GNMT overexpression by adenovirus-mediated transfer in cortical mixed neuron-glial cultures. Infection of adenovirus encoding green fluorescence protein to cultures demonstrates high preference for non-neuronal cells. Optimal GNMT overexpression in cultures by adenoviral GNMT (Ad-GNMT) infection not only induces protein kinase C phosphorylation, but also increases neuronal/oligodendroglial survival. Furthermore, these Ad-GNMT-infected cultures are significantly resistant to H(2)O(2) toxicity and lipopolysaccharide stimulation. Conditioned media from Ad-GNMT-infected microglia also significantly enhance neuronal survival. Taken together, enhanced GNMT expression in mixed neuronal-glial cultures is neuroprotective, most likely mediated through non-neuronal cells.

Enhanced Prostacyclin Synthesis by Adenoviral Gene Transfer Reduced Glial Activation and Ameliorated Dopaminergic Dysfunction in Hemiparkinsonian Rats

“…Highly purified adenoviruses encoding GFP, PGIS, and bicistronic COX-1/PGIS, ranging from 10 10 ~10 11  pfu/mL, were used in the present study. Previously, we have demonstrated high permissivity of mixed glial cultures to AdGFP infection [22]. Almost all cells expressed GFP at 2 days after 20 MOIs of Ad-GFP transduction (Similar results are shown in Figure 4(f)).…”

“…Mixed neuronal/glial cell cultures were prepared from the mesencephalic region of embryonic Sprague-Dawley (SD) rat fetus at gestation of 14–16 days as described in Tsai et al [22, 23]. Briefly, cells were dissociated with mixtures of papain/protease/deoxyribonuclease I (0.1% : 0.1% : 0.03%) and plated onto poly-D-lysine coated dishes at a density of 1~2 × 10 5  cells/cm 2 in DMEM supplemented with 10% FBS.…”

Glycine N‐methyltransferase expression in the hippocampus and its role in neurogenesis and cognitive performance

“…However, the low levels found suggest that only a specific subtype of nerve cells may express GNMT, in clear contrast with the liver, where all hepatocytes are well supplied with this enzyme. The results described here are in agreement with those reported by Tsai et al () in which they did not find GNMT protein in the cerebral cortex and with those of Yang et al () in which they found that GNMT mRNA expression in the hippocampus is 1.5‐fold higher than in cortex and 700‐ to 1,000‐fold less than in liver.…”

Recovery of neurological function of ischemic stroke by application of conditioned medium of bone marrow mesenchymal stem cells derived from normal and cerebral ischemia rats

“…Cortical neuronal cultures were prepared from the cerebrocortical regions of Sprague–Dawley (SD) rat fetuses at gestation 15–17 days as described in Tsai et al [24-26]. In brief, fetal cortexes were dissociated with mixtures of papain/protease/deoxyribonuclease I (0.1%: 0.1%: 0.03%).…”