Liposome-entrapped GABA modulates the expression of nNOS in NG108-15 cells

Abstract

Background Liposomes are concentric lipid vesicles that allow a sustained release of entrapped substances. GABA (γ-aminobutyric acid) is the most prevalent inhibitory neurotransmitter in the central nervous system. New method Using GABA-containing liposomes (GL) prepared by the freeze-thawing method, we determined the effect of sustained release of GABA on expression of neuronal nitric oxide synthase (nNOS) and GABAA receptor (GABAAR) in an in vitro neuronal model. Results Neuronal cell line NG108-15 treated with different doses of GL during 24 h showed an increase in expression of GABAAR (54 and 50% with 10 and 20 ng doses, respectively) and nNOS (138, 157 and 165% with 20, 50 and 100 ng doses, respectively) compared with cells treated with empty liposomes (EL). Additionally, cells treated with 50 ng of GL showed an increase in GABAAR (23%) after 1h followed by an increase in nNOS (55, 46 and 55%) at 8, 12 and 24h time points, respectively. Immunofluorescence experiments confirmed an increase in nNOS (134%) and basal intracellular levels of nitric oxide (84%) after GL treatment. Further, treatment of cells with GL showed a decrease in expression of protein inhibitor of nNOS (PIN) (26, 66 and 57% with 20, 50 and 100 ng doses respectively) compared with control. Comparison with existing methods This is first demonstration for the development of GL that allows sustained slow release of this neurotransmitter. Conclusion These results suggest that a slow release of GABA can change the expression of nNOS possibly via alteration in PIN levels in neuronal cells.

Two Receptors, Two Isoforms, Two Cancers: Comprehensive Analysis of KIT and TrkA Expression in Neuroblastoma and Acute Myeloid Leukemia

“…Loss of sensitivity to NO due to constant NOS1 overexpression can be one of the mechanisms that block NB differentiation (53). NOS1 expression can be increased by the stimulation of NB cells with GABA-containing liposomes, although the particular role of GABA type A receptor subunit alpha 5 ( GABRA5 ) in this process is unknown (88). There are reports that GABA-A receptor agonists induce apoptosis in NB cells, although the high expression of some GABA receptor subunits correlates a with poor prognosis in NB (89, 90).…”

Nanocapsules for Programmed Neurotransmitter Release: Toward Artificial Extracellular Synaptic Vesicles

“…In this system, the release of drug molecules from mesoporous silica nanospheres is triggered by adding disulfide bond‐reducing molecules such as dithiothreitol and mercaptoethanol in vitro. Nanoparticles have been considered for encapsulation of neurotransmitters of several kinds such as dopamine, leucine‐enkephalin, glutamate, neuropeptide substance P, acetylcholine, adenosine, and GABA . Nevertheless, few in vitro studies have succeeded in the on‐demand release of neurotransmitters .…”

GABA-containing liposomes: neuroscience applications and translational perspectives for targeting neurological diseases

“…Second, a marked increase in nitric oxide (NO), an important mediator of intracellular signaling in the central nervous system. The increase in nitric oxide possibly results from a reduction in PIN, the endogenous protein inhibitor of neuronal nitric oxide synthase (nNOS) [37]. PIN binding leads to destabilization of active nNOS dimers resulting in the formation of functionally impeded catalytically inactive monomers and hence decrease in NO formation [38].…”

“…The observed increase in NO in neurons exposed to GABA-containing liposomes might be due to stabilization of nNOS dimers. Recent functional findings of our GABA liposomes formulation [35,37] are mentioned in some specific topics below.…”

“…Part of the mechanisms by which microglia can enhance the neurotoxicity of amyloid β-protein is via the production of reactive oxygen species [67,68]. Considering our current data showing that GABA-containing liposomes can improve nitric oxide availability in neuronal populations [37], the influence of GABA-containing liposomes on amyloid β-protein toxicity on neurons remains to be examined.…”