Nicotinamide mononucleotide adenylyltransferase maintains active zone structure by stabilizing Bruchpilot
2013; 14 (1): 87-94
Human amniotic epithelial cells ameliorate behavioral dysfunction and reduce infarct size in the rat middle cerebral artery occlusion model
2008; 29 (5): 603-611
Active zones are specialized presynaptic structures critical for neurotransmission. We show that a neuronal maintenance factor, nicotinamide mononucleotide adenylyltransferase (NMNAT), is required for maintaining active zone structural integrity in Drosophila by interacting with the active zone protein, Bruchpilot (BRP), and shielding it from activity-induced ubiquitin-proteasome-mediated degradation. NMNAT localizes to the peri-active zone and interacts biochemically with BRP in an activity-dependent manner. Loss of NMNAT results in ubiquitination, mislocalization and aggregation of BRP, and subsequent active zone degeneration. We propose that, as a neuronal maintenance factor, NMNAT specifically maintains active zone structure by direct protein-protein interaction.
View details for DOI 10.1038/embor.2012.181
View details for Web of Science ID 000316980300019
View details for PubMedID 23154466
Early chronic blockade of NR2B subunits and transient activation of NMDA receptors modulate LTP in mouse auditory cortex.
2006; 1073-1074: 131-138
Human amniotic epithelial cells (hAECs), having the characteristics of both embryonic and pluripotent stem cells, have the potential to differentiate into various cells. A good deal of research has explored the clinical therapeutic potential of hAECs; rat amniotic epithelial cells have been reported to ameliorate functional deficits after stroke in rats, likely due to neuronal differentiation and cytokine secretion by these cells. We isolated hAECs and transfected them with glial cell line-derived neurotrophic factor (GDNF) or enhanced green fluorescent protein (EGFP) gene using lentiviral vectors. These cells were then transplanted into the brains of rats subjected to a transient middle cerebral artery occlusion. The hAECs survived and migrated to the ischemic area of rats, and some of the transplanted hAECs expressed the neuronal marker MAP2 and the neuronal progenitor marker Nestin, together with the astrocyte marker glial fibrillary acidic protein, and hAEC-EGFP can significantly ameliorate behavioral dysfunction and reduce infarct volume of ischemic rats. By transfecting the cells with lentiviral vectors, GDNF can be stably overexpressed in hAECs, and hAEC-GDNF can more rapidly rescue the deficits of rats after middle cerebral artery occlusion compared with hAEC-EGFP-treated rats. Moreover, the nontransduced cells also had effects comparable to the GDNF-transduced cells on caspase-3 and lesion volume. Because hAECs are in unlimited supply, and their use is not encumbered by ethical arguments, hAECs have a great advantage for stem cell therapy. This model holds tremendous potential for development into wide use in cell-mediated gene therapy in the future.
View details for DOI 10.1097/SHK.0b013e318157e845
View details for Web of Science ID 000255210900011
View details for PubMedID 18414234
In the auditory cortex, the properties of NMDA receptors depend primarily on the ratio of NR2A and NR2B subunits. NR2B subunit expression is high at the beginning of critical period and lower in adulthood. Because NMDA receptors are crucial in triggering long-term potentiation (LTP) and long-term depression, developmental or experience-dependent modification of NMDAR subunit composition is likely to influence synaptic plasticity. To examine how NMDA subunit change during postnatal development affect the adult synaptic plasticity, we employed chronic ifenprodil blockade of NR2B subunits and analyzed evoked field potentials in adult C57BL/6 mice auditory cortex (AC). We found that chronic loss of NR2B activity led to a decline in LTP magnitude in the AC of adult mice. Adding NMDA to the artificial cerebrospinal fluid (ACSF) in blocked mice had the opposite effect, producing LTP magnitudes at or exceeding those found in treated or untreated animals. These results suggest that, even in adulthood when NR2B expression is downregulated, these receptor subunits play an important role in experience-dependent plasticity of mouse auditory cortex. Blockade from P60 did not result in any decrease of LTP amplitude, suggesting that chronic block in postnatal period may permanently affect cortical circuits so that they cannot produce significant LTP in adulthood.
View details for PubMedID 16457785