NGF gene expression in dividing and non-dividing cells from AAV-derived constructs

Adeno-associated virus mediated gene transfer into primary rat brain neuronal and glial cultures: enhancement with the pH-sensitive surfactant dodecyl 2-(1'-imidazolyl) propionate

This study evaluated the effects of a novel, pH-sensitive surfactant, dodecyl 2-(1'-imidazolyl) propionate (DIP), on cationic lipid mediated transfection in primary rat brain neuronal and glial cultures. The cationic lipid complex DOTAP/DOPE (1, 2-dioleoyl-3-trimethylammonium propionate and dioleoyl phosphatidylethanolamine, respectively) was added over a range of concentrations (0-120 microg/ml) with DNA concentration kept constant (1.6 microg/ml). The neuron-specific enolase (NSE) and cytomegalovirus (CMV) promoters were found to drive green fluorescent protein (GFP) expression in neuron-enriched and glial cultures, respectively, using adeno-associated virus (AAV) derived constructs. NSE-driven GFP expression was not observed in glial cultures. Addition of DOTAP/DOPE increased transfection efficiency over a wide range of lipid concentrations (5-50 microg/ml) keeping DNA concentration constant (1.6 microg/ml). Addition of DIP to the lipid/DNA complex increased maximum transfection efficiencies in glial and neuronal cultures 2-3-fold. Transfection efficiencies were at their maximum with a similar total lipid concentration (50 microg/ml) in both cell-types in the presence of DIP. Neuronal cultures were more sensitive than glia to the toxic actions of DOTAP/DOPE, with or without DIP. These results indicate that AAV-mediated gene-transfer to neurons and glia can be facilitated by addition of a pH-sensitive surfactant to cationic liposome/DNA complexes and that endosomal escape could be a limiting factor in transgene expression.

Intravenous angiotensinogen antisense in AAV-based vector decreases hypertension

Angiotensinogen (AGT) has been linked to hypertension. Because there are no direct inhibitors of AGT, we have developed antisense (AS) inhibition of AGT mRNA delivered in an adeno-associated virus (AAV)-based plasmid vector. This plasmid, driven by the cytomegalovirus promoter, contains a green fluorescent protein reporter gene and AS cDNA for rat AGT. Transfection of the plasmid into rat hepatoma cells brought a strong expression of the transgenes and a significant reduction in the level of AGT. In the in vivo study, naked plasmid DNA was intravenously injected into adult spontaneously hypertensive rats at different doses (0.6, 1.5, and 3 mg/kg). Expression of AGT AS mRNA was present in liver and heart, and it lasted longer in the liver. All three doses produced a significant decrease in blood pressure (BP). BP decreased for 2, 4, and 6 days, respectively. The lowest dose decreased BP by 12 +/- 3.0 mmHg, whereas the higher doses decreased BP by up to 22.5 +/- 5.2 mmHg compared with the control rats injected with saline (P < 0.01). The injection of the plasmid with liposomes produced a more profound and longer reduction (8 days) in BP. Consistent changes in plasma AGT level were observed. Sense plasmid had no effect. No liver toxicity was observed after injection of AS plasmid with or without liposomes. Our results suggest that the systemic delivery of AS against AGT mRNA by AAV-based plasmid vector, especially with liposomes, may have potential for gene therapy of hypertension and that further studies with the plasmid packaged into a recombinant AAV vector for a longer-lasting AS effect are warranted.

Drosophila melanogaster as a model system for the study of the function of calcium/calmodulin-dependent protein kinase II in synaptic plasticity

Drosophila melanogaster has been used as a biological model system for almost a century. In the last several decades, Drosophila has been used as a system to probe the molecular basis of behavior and discoveries in the fly have been at the forefront of the elucidation of important basic mechanisms. This review will outline the variety of approaches that make Drosophila an excellent model system with which to study the function of the enzyme calcium/calmodulin-dependent protein kinase II (CaMKII) in synaptic plasticity. CaMKII has a well documented role in behavior and synaptic plasticity in both vertebrates and invertebrates. The behavioral and genetic richness of Drosophila allow for a multi-level approach to understanding the physiological roles of this enzyme's function.