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

Gamma-aminobutyric acid-mediated neuro-immune interactions in glioblastoma: Implications for prognosis and immunotherapy response

AIMS

This study aimed to investigate the role of gamma-aminobutyric acid (GABA) in the glioblastoma (GBM) tumor immune microenvironment (TIME) and its impact on prognosis and response to immunotherapy.

MAIN METHODS

This study employed single-cell RNA sequencing (scRNA-seq) to delineate the TIME of GBM, utilized non-negative matrix factorization (NMF) for GABA-associated cell clustering, and performed pseudotime analysis for cellular trajectories. Additionally, we integrated immunohistochemistry (IHC), immunofluorescence (IF), and protein-protein interaction (PPI) analysis to explore the regulatory mechanisms within the tumor microenvironment.

KEY FINDINGS

The study identified distinct GABA-associated immune cell subtypes, particularly macrophages and T-cells, with unique gene expression and developmental trajectories. The development of the GABA-associated scoring model (GABAAS), introduced novel prognostic indicators, enhancing our ability to predict patient outcomes. This study also suggests that GABA-related genes, including NDRG2 and TIMP1, play a crucial role in immune modulation, with potential implications for immunotherapy responsiveness.

SIGNIFICANCE

The findings underscore the potential of targeting GABA-related genes (NDRG2 and TIMP1) and M2 macrophage to reshape the glioblastoma immune landscape, offering a new frontier in personalized neuro-immunotherapy. This approach holds promise to counter individual tumor immunosuppressive mechanisms, enhancing patient outcomes.

Cell-specific extracellular vesicle-encapsulated exogenous GABA controls seizures in epilepsy

BACKGROUND

Epilepsy affects ∼60 million people worldwide. Most antiseizure medications in the market act on voltage-gated sodium or calcium channels, indirectly modulating neurotransmitter GABA or glutamate levels or multiple targets. Earlier studies made significant efforts to directly deliver GABA into the brain with varied success. Herein, we have hypothesized to directly deliver exogenous GABA to the brain with epilepsy through extracellular vesicles (EVs) from human GABA-producing cells and their progenitors as EVs largely mimic their parent cell composition.

METHODS

Human neural stem cells (NSCs), medial ganglionic eminence (MGE) cells, and GABAergic interneurons (INs) were generated from induced pluripotent stem cells (iPSCs) and characterized. EVs were isolated from NSCs, MGE cells, and INs and characterized for size and distribution, morphological features, and molecular markers. Exogenous GABA was passively loaded to the isolated EVs as a zwitterion at physiological pH, and the encapsulated dose of GABA was quantified. Epilepsy was developed through status epilepticus induction in Fisher rats by administration of repeated low doses of kainic acid. The extent of the seizures was measured for 10 h/ day for 3-6 months by video recording and its evaluation for stage III, IV and V seizures as per Racine scale. EVs from INs, MGE cells, and NSCs encapsulated with exogenous GABA were sequentially tested in the 4th, 5th, and 6th months by intranasal administration in the rats with epilepsy for detailed seizure, behavioral and synapse analysis. In separate experiments, several controls including exogenic GABA alone and EVs from INs and MGE cells were evaluated for seizure-controlling ability.

RESULTS

Exogenic GABA could enter the brain through EVs. Treatment with EVs from INs and MGE cells encapsulated with GABA significantly reduced total seizures, stage V seizures, and total time spent in seizure activity. EVs from NSCs encapsulated with GABA demonstrated limited seizure control. Exogenic GABA alone and EVs from INs and MGE cells individually failed to control seizures. Further, exogenic GABA with EVs from MGE cells improved depressive behavior while partially improving memory functions. Co-localization studies confirmed exogenous GABA with presynaptic vesicles in the hippocampus, indicating the interaction of exogenous GABA in the brain with epilepsy.

CONCLUSION

For the first time, the study demonstrated that exogenous GABA could be delivered to the brain through brain cell-derived EVs, which could regulate seizures in temporal lobe epilepsy. It is identified that the cellular origin of EVs plays a vital role in seizure control with exogenous GABA.

Key structural factors and intermolecular interactions underlying the formation, functional properties and behaviour in the gastrointestinal tract in vitro of the liposomal form of nutraceuticals coated with whey proteins and chitosan

The aim of this study was to gain a better understanding of the key structural factors and intermolecular interactions underlying the formation, functionality, and in vitro gastrointestinal behaviour of the liposomal form of nutraceuticals coated with whey proteins (WPI) and chitosan (CHIT). Phosphatidylcholine (PC) liposomes were used to encapsulate a combination of hydrophobic and hydrophilic nutraceuticals. The hydrophobic constituents were long-chain (LC) n-3 PUFAs (DHA and EPA) from fish oil (FO), vitamin D3, and clove essential oil (CEO), while the hydrophilic component was γ-aminobutyric acid (GABA). A combination of physicochemical methods was used to achieve this goal, including electron paramagnetic resonance spectroscopy (EPRS), laser light scattering in dynamic, static, and electrophoretic modes, transmission electron microscopy, spectrophotometry and tensiometry. The efficiency of encapsulating the nutraceuticals in PC liposomes simultaneously was as follows: 100 ± 1% for both FO triglycerides and CEO, 82 ± 2% for vitamin D3, and 50 ± 1% for GABA. According to EPRS data, encapsulating LC PUFA reduced microviscosity at a depth of 20 Å in the PC bilayer. The co-encapsulation of other nutraceuticals in PC liposomes at selected concentrations did not alter this effect. The upper part (8 Å) of PC liposome bilayers showed an increase in rigidity parameter S, indicating the presence of D3, CEO, and partially GABA. The liposome layer-by-layer encapsulation efficiency (EE%) was achieved by using WPI to form the binary complex [WPI-(PC-FO-D3-GABA-CEO)] (EE = 50% at pH 7.0 and I = 0.001 M), followed by coating with chitosan to form the ternary complex [WPI-(PC-FO-D3-GABA-CEO)]-CHIT (EE = 80% at pH 5.1 and I = 0.001 M). The biopolymer-coated liposomes displayed high water solubility owing to their submicron sizes, thermodynamic affinity for the aqueous medium, and 20 mV ζ-potential values. The chitosan shell regulated the release of liposomes from the ternary complex during in vitro gastrointestinal digestion. In the stomach, the hydrolysis of chitosan by pepsin resulted in a 40% release of liposomes. In the small intestine, chitosan was separated from the WPI-liposome core, facilitatig its hydrolysis and resulting in a 60% release of liposomes. The bioavailability of nutraceuticals encapsulated in PC liposomes in the small intestine may be enhanced by the interactions of both non-hydrolysed and hydrolysed liposomes with bile salts and mucin.

Identification of Novel Prognostic Biomarkers That are Associated with Immune Microenvironment Based on GABA-Related Molecular Subtypes in Gastric Cancer

Background

Gamma-aminobutyric acid (GABA) plays an important role in tumorigenesis and progression. Despite this, the role of Reactome GABA receptor activation (RGRA) on gastric cancer (GC) remains unclear. This study was intended to screen RGRA-related genes in GC and investigate their prognostic value.

Methods

GSVA algorithm was used to assess the score of RGRA. GC patients were divided into two subtypes based on the median score of RGRA. GSEA, functional enrichment analysis, and immune infiltration analysis were performed between the two subgroups. Then, differentially expressed analysis, and weighted gene co-expression network analysis (WGCNA) were used to identify RGRA-related genes. The prognosis and expression of core genes were analyzed and validated in the TCGA database, GEO database, and clinical samples. ssGSEA and ESTIMATE algorithms were used to assess the immune cell infiltration in the low- and high-core genes subgroups.

Results

High-RGRA subtype had a poor prognosis and activated immune-related pathways, as well as an activated immune microenvironment. ATP1A2 was identified to be the core gene. The expression of ATP1A2 was associated with the overall survival rate and tumor stage, and its expression was down-regulated in GC patients. Furthermore, ATP1A2 expression was positively correlated with the level of immune cells, including B cells, CD8 T cells, cytotoxic cells, DC, eosinophils, macrophages, mast cells, NK cells, and T cells.

Conclusion

Two RGRA-related molecular subtypes were identified that could predict the outcome in GC patients. ATP1A2 was a core immunoregulatory gene and was associated with prognosis and immune cell infiltration in GC.

Exploration of the Shared Molecular Mechanisms between COVID-19 and Neurodegenerative Diseases through Bioinformatic Analysis

The COVID-19 pandemic has caused millions of deaths and remains a major public health burden worldwide. Previous studies found that a large number of COVID-19 patients and survivors developed neurological symptoms and might be at high risk of neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). We aimed to explore the shared pathways between COVID-19, AD, and PD by using bioinformatic analysis to reveal potential mechanisms, which may explain the neurological symptoms and degeneration of brain that occur in COVID-19 patients, and to provide early intervention. In this study, gene expression datasets of the frontal cortex were employed to detect common differentially expressed genes (DEGs) of COVID-19, AD, and PD. A total of 52 common DEGs were then examined using functional annotation, protein-protein interaction (PPI) construction, candidate drug identification, and regulatory network analysis. We found that the involvement of the synaptic vesicle cycle and down-regulation of synapses were shared by these three diseases, suggesting that synaptic dysfunction might contribute to the onset and progress of neurodegenerative diseases caused by COVID-19. Five hub genes and one key module were obtained from the PPI network. Moreover, 5 drugs and 42 transcription factors (TFs) were also identified on the datasets. In conclusion, the results of our study provide new insights and directions for follow-up studies of the relationship between COVID-19 and neurodegenerative diseases. The hub genes and potential drugs we identified may provide promising treatment strategies to prevent COVID-19 patients from developing these disorders.

Neurodevelopmental Toxicity of Emamectin Benzoate to the Early Life Stage of Zebrafish Larvae (Danio rerio)

Emamectin benzoate (EMB) is a widely used pesticide and feed additive in agriculture and aquaculture. It easily enters the aquatic environment through various pathways, thus causing adverse effects on aquatic organisms. However, there are no systematic studies regarding the effects of EMB on the developmental neurotoxicity of aquatic organisms. Therefore, the aim of this study was to evaluate the neurotoxic effects and mechanisms of EMB at different concentrations (0.1, 0.25, 0.5, 1, 2, 4 and 8 μg/mL) using zebrafish as a model. The results showed that EMB significantly inhibited the hatching rate, spontaneous movement, body length, and swim bladder development of zebrafish embryos, as well as significantly increased the malformation rate of zebrafish larvae. In addition, EMB adversely affected the axon length of motor neurons in Tg (hb9: eGFP) zebrafish and central nervous system (CNS) neurons in Tg (HuC: eGFP) zebrafish and significantly inhibited the locomotor behavior of zebrafish larvae. Meanwhile, EMB induced oxidative damage and was accompanied by increasing reactive oxygen species in the brains of zebrafish larvae. In addition, gene expression involvement in oxidative stress-related (cat, sod and Cu/Zn-sod), GABA neural pathway-related (gat1, gabra1, gad1b, abat and glsa), neurodevelopmental-related (syn2a, gfap, elavl3, shha, gap43 and Nrd) and swim bladder development-related (foxa3, pbxla, mnx1, has2 and elovlla) genes was significantly affected by EMB exposure. In conclusion, our study shows that exposure to EMB during the early life stages of zebrafish significantly increases oxidative damage and inhibits early central neuronal development, motor neuron axon growth and swim bladder development, ultimately leading to neurobehavioral changes in juvenile zebrafish.

New Trends in Fluorescent Nanomaterials-Based Bio/Chemical Sensors for Neurohormones Detection-A Review

The study of neurotransmitters and stress hormones allows the determination of indicators of the current stress load in the body. These species also create a proper strategy of stress protection. Nowadays, stress is a general factor that affects the population, and it may cause a wide range of serious disorders. Abnormalities in the level of neurohormones, caused by chronic psychological stress, can occur in, for instance, corporate employees, health care workers, shift workers, policemen, or firefighters. Here we present a new nanomaterials-based sensors technology development for the determination of neurohormones. We focus on fluorescent sensors/biosensors that utilize nanomaterials, such as quantum dots or carbon nanomaterials. Nanomaterials, owing to their diversity in size and shape, have been attracting increasing attention in sensing or bioimaging. They possess unique properties, such as fluorescent, electronic, or photoluminescent features. In this Review, we summarize new trends in adopting nanomaterials for applications in fluorescent sensors for neurohormone monitoring.

Applications of Various Types of Nanomaterials for the Treatment of Neurological Disorders

Neurological disorders (NDs) are recognized as one of the major health concerns globally. According to the World Health Organization (WHO), neurological disorders are one of the main causes of mortality worldwide. Neurological disorders include Alzheimer’s disease, Parkinson′s disease, Huntington′s disease, Amyotrophic lateral sclerosis, Frontotemporal dementia, Prion disease, Brain tumor, Spinal cord injury, and Stroke. These diseases are considered incurable diseases because no specific therapies are available to cross the blood-brain barrier (BBB) and reach the brain in a significant amount for the pharmacological effect in the brain. There is a need for the development of strategies that can improve the efficacy of drugs and circumvent BBB. One of the promising approaches is the use of different types of nano-scale materials. These nano-based drugs have the ability to increase the therapeutic effect, reduce toxicity, exhibit good stability, targeted delivery, and drug loading capacity. Different types and shapes of nanomaterials have been widely used for the treatment of neurological disorders, including quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These nanoparticles have unique characteristics, including sensitivity, selectivity, and the ability to cross the BBB when used in nano-sized particles, and are widely used for imaging studies and treatment of NDs. In this review, we briefly summarized the recent literature on the use of various nanomaterials and their mechanism of action for the treatment of various types of neurological disorders.

Granulocyte-colony stimulating factor gene therapy as a novel therapeutics for stroke in a mouse model

Background

Global ischemia is the resulting effect of a cardiopulmonary arrest (CPA). Presently there is no effective treatment to address neurological deficits in patients who survived a CPA. Granulocyte-colony stimulating factor is a growth factor (G-CSF) with a plethora of beneficial effects, including neuroprotection. Clinical application of human G-CSF (hG-CSF) is limited due to its plasma half-life of 4 h. Therefore, novel approaches need to be investigated that would (1) enable prolonged manifestation of hG-CSF and (2) demonstrate G-CSF efficacy from studying the underlying protective mechanisms of hG-CSF. In our previous work, we used the self-complementary adeno-associated virus (stereotype2: scAAV2) as a vector to transfect the hG-CSF gene into the global ischemic brain of a mouse. As an extension of that work, we now seek to elucidate the protective mechanisms of hG-CSF gene therapy against endoplasmic reticulum induced stress, mitochondrial dynamics and autophagy in global ischemia.

Method

A single drop of either AAV-CMV-hG-CSF or AAV-CMV-GFP was dropped into the conjunctival sac of the Swiss Webster mouse’s left eye, 30–60 min after bilateral common artery occlusion (BCAO). The efficacy of the expressed hG-CSF gene product was analyzed by monitoring the expression levels of endoplasmic reticulum stress (ER), mitochondrial dynamics and autophagic proteins over 4- and 7-days post-BCAO in vulnerable brain regions including the striatum, overlying cortex (frontal brain regions) and the hippocampus (middle brain regions). Statistical analysis was performed using mostly One-Way Analysis of variance (ANOVA), except for behavioral analysis, which used Repeated Measures Two-Way ANOVA, post hoc analysis was performed using the Tukey test.

Results

Several biomarkers that facilitated cellular death, including CHOP and GRP78 (ER stress) DRP1 (mitochondrial dynamics) and Beclin 1, p62 and LC3-ll (autophagy) were significantly downregulated by hG-CSF gene transfer. hG-CSF gene therapy also significantly upregulated antiapoptotic Bcl2 while downregulating pro-apoptotic Bax. The beneficial effects of hG-CSF gene therapy resulted in an overall improvement in functional behavior.

Conclusion

Taken together, this study has substantiated the approach of sustaining the protein expression of hG-CSF by eye drop administration of the hG-CSF gene. In addition, the study has validated the efficacy of using hG-CSF gene therapy against endoplasmic reticulum induced stress, mitochondrial dynamics and autophagy in global ischemia.

Nanocarriers for effective nutraceutical delivery to the brain

Neurodegenerative disorders are common among aging populations around the globe. Most are characterized by loss of neurons, protein aggregates, oxidative stress, mitochondrial damage, neuroinflammation among others. Although symptomatic treatment using conventional pharmacotherapy has been widely employed, their therapeutic success is limited due to varied reasons. In the need to identify an alternative approach, researchers successfully demonstrated the therapeutic utility of plant-derived nutraceuticals in cell and animal models of neurodegenerative conditions. However, most nutraceuticals failed during clinical trials in humans owing to their poor bioavailability in vivo and limited permeability across the blood brain barrier (BBB). The current emphasis is therefore on the improved delivery of nutraceuticals to the brain. In this regard, development of nanoparticle conjugated nutraceuticals to enhance bioavailability and therapeutic efficacy in the brain has gained attention. Here, we review the research advances in nanoparticles conjugated nutraceuticals applied in neurodegenerative disorders and discuss their advantages and limitations, clinical trials and toxicity concerns.

Drp1 is widely, yet heterogeneously, distributed in the mouse central nervous system

Objectives

Drp1 is widely expressed in the mouse central nervous system and plays a role in inducing the mitochondrial fission process. Many diseases are associated with Drp1 and mitochondria. However, since the exact distribution of Drp1 has not been specifically observed, it is difficult to determine the impact of anti-Drp1 molecules on the human body. Clarifying the specific Drp1 distribution could be a good approach to targeted treatment or prognosis.

Methods

We visualized the distribution of Drp1 in different brain regions and explicated the relationship between Drp1 and mitochondria. GAD67-GFP knock-in mice were utilized to detect the expression patterns of Drp1 in GABAergic neurons. We also further analyzed Drp1 expression in human malignant glioma tissue.

Results

Drp1 was widely but heterogeneously distributed in the central nervous system. Further observation indicated that Drp1 was highly and heterogeneously expressed in inhibitory neurons. Under transmission electron microscopy, the distribution of Drp1 was higher in dendrites than other areas in neurons, and only a small amount of Drp1 was localized in mitochondria. In human malignant glioma, the fluorescence intensity of Drp1 increased from grade I-III, while grade IV showed a declining trend.

Conclusion

In this study, we observed a wide heterogeneous distribution of Drp1 in the central nervous system, which might be related to the occurrence and development of neurologic disease. We hope that the relationship between Drp1 and mitochondria may will to therapeutic guidance in the clinic.

Lipid vesicles: applications, principal components and methods used in their formulations: A review

Liposomes and niosomes are currently the most studied lipid vesicles in the nanomedicine field. The system formed by a phospholipid bilayer in aqueous medium allows these vesicles to carry both hydrophilic and lipophilic compounds, providing an increase in solubility of drugs lready used in conventional therapy. The focus on the development of these vesicles should be directed to determining the ideal composition, with low toxicity, biocompatibility and which remains stable for long periods. These characteristics are related to the components used for formulation and the substances that will be encapsulated. Another important point relates to the methods used during formulation, which are important in determining the type of vesicle formed, whether these be large or small, unilamellar or multilamellar. Because of the deliberate actions applied in the development of these vesicles, this review sought to gather updated information regarding the different methods used, including their main components while considering the behavior of each of them when used in different formulations. Also, data showing the importance of formulations in the medical field evidencing studies performed with liposome and niosome vesicles as promising in this area, and others, were included. The approach allows a better understanding of the participation of components in formulations such as cholesterol and non-ionic surfactants, as well as the basis for choosing the ideal components and methods for future research in the development of these vesicles.

Carbon dots as versatile nanoarchitectures for the treatment of neurological disorders and their theranostic applications: A review

The development of novel methods plays a fundamental role in early diagnosis and controlling of neurological disorders (NDs). Blood-brain barrier (BBB) is the most challenging barrier for the development of neuro drug delivery systems due to its inhibiting ability to enter drugs and agents into central nervous system (CNS). Carbon dots (CDs) have shown to be very promising and outstanding agents for various biomedical applications (bio imaging studies, treatment of NDs and brain tumors). They exhibit remarkable properties such as biocompatibility, small size (less than 10 nm, enabling penetration into BBB), tunable optical properties, photostability and simple synthetic procedures, allowing them to act as ideal candidates in various fields of science. Therefore, the objective of this review is to overview the recent studies on CDs for the development of neuro drug delivery systems to reach CNS via crossing of BBB. Primarily, this review briefly outlines the unique optical properties and toxicity of CDs. The development of novel neuro drug delivery systems for various neurological disorders using CDs as carriers is described. This review also covers the potential applications of CDs in brain tumors imaging and treatment of neurodegenerative diseases. Finally, the sensing applications and future prospects of CDs are summarized.

Synthesis and characterization of acetyl curcumin-loaded core/shell liposome nanoparticles via an electrospray process for drug delivery, and theranostic applications

Despite substantial advancements in divergent drug delivery systems (DDS), there is still room for novel and innovative nanoparticle-mediated drug delivery methodologies such as core/shell liposomes to deliver drugs in a kinetically controlled manner into the active site without any side effects. Herein, ((1E,6E)-3,5-dioxohepta-1,6-diene-1,7-diyl) bis (2-methoxy-4,1-phenylene) diacetate acetyl curcumin (AC)-loaded poly(lactic-co-glycolic acid) (PLGA) core/shell liposome nanoparticles (ACPCSLNPs) were prepared using an electron spray method under an applied electric field, which facilitated the uniform formation of nano-sized liposome nanoparticles (LNPs). Then, kinetically controlled and sustained drug release profiles were investigated using the as-prepared ACPCSLNPs. Moreover, the inner polymeric core could not only induce the generation of electrostatic interactions between the polymer and drug molecules but could also affect the prominent repulsions between the polar head groups of lipids and the nonpolar drug molecules. As a result, the sustained maximum release of the drug molecules (~48.5%) into the system was observed over a long period (~4 days). Furthermore, cell cytotoxicity studies were conducted in a human cervical cancer cell line (HeLa) and a healthy human dermal fibroblast cell line (HDFa) by employing all AC loaded LNPs along with free drugs. Multicolor cell imaging was also observed in HeLa cells using ACPCSLNPs. Notably, more curcumin was released from the ACPCSLNPs than AC due to the presence of polar group attractions and polar-polar interactions between the lipid head groups and curcumin since curcumin is more soluble than AC in aqueous medium. In addition, the predictions of the release kinetic patterns were also investigated thoroughly using the exponential-based Korsmeyer-Peppas (K-P) and Higuchi models for drug-loaded LNPs and PLGA NPs, respectively.

Nanocapsules for Programmed Neurotransmitter Release: Toward Artificial Extracellular Synaptic Vesicles

Nanocapsules present a promising platform for delivering chemicals and biomolecules to a site of action in a living organism. Because the biological action of the encapsulated molecules is blocked until they are released from the nanocapsules, the encapsulation structure enables triggering of the topical and timely action of the molecules at the target site. A similar mechanism seems promising for the spatiotemporal control of signal transduction triggered by the release of signal molecules in neuronal, metabolic, and immune systems. From this perspective, nanocapsules can be regarded as practical tools to apply signal molecules such as neurotransmitters to intervene in signal transduction. However, spatiotemporal control of the payload release from nanocapsules persists as a key technical issue. Stimulus-responsive nanocapsules that release payloads in response to external input of physical stimuli are promising platforms to enable programmed payload release. These programmable nanocapsules encapsulating neurotransmitters are expected to lead to new insights and perspectives related to artificial extracellular synaptic vesicles that might provide an experimental and therapeutic strategy for neuromodulation and nervous system disorders.