The Comparative Utility of Viromer RED and Lipofectamine for Transient Gene Introduction into Glial Cells

Poly (β-amino Ester) Nanoparticles Modified with a Rabies Virus-derived peptide for the Delivery of ASCL1 Across a 3D In Vitro Model of the Blood Brain Barrier

Gene editing has emerged as a therapeutic approach to manipulate the genome for killing cancer cells, protecting healthy tissues, and improving immune response to a tumor. The gene editing tool achaete-scute family bHLH transcription factor 1 CRISPR guide RNA (ASCL1-gRNA) is known to restore neuronal lineage potential, promote terminal differentiation, and attenuate tumorigenicity in glioblastoma tumors. Here, we fabricated a polymeric nonviral carrier to encapsulate ASCL1-gRNA by electrostatic interactions and deliver it into glioblastoma cells across a 3D in vitro model of the blood-brain barrier (BBB). To mimic rabies virus (RV) neurotropism, gene-loaded poly (β-amino ester) nanoparticles are surface functionalized with a peptide derivative of rabies virus glycoprotein (RVG29). The capability of the obtained NPs, hereinafter referred to as RV-like NPs, to travel across the BBB, internalize into glioblastoma cells and deliver ASCL1-gRNA are investigated in a 3D BBB in vitro model through flow cytometry and CLSM microscopy. The formation of nicotinic acetylcholine receptors in the 3D BBB in vitro model is confirmed by immunochemistry. These receptors are known to bind to RVG29. Unlike Lipofectamine that primarily internalizes and transfects endothelial cells, RV-like NPs are capable to travel across the BBB, preferentially internalize glioblastoma cells and deliver ASCL1-gRNA at an efficiency of 10 % causing non-cytotoxic effects.

Latent Tri-lineage Potential of Human Menstrual Blood-Derived Mesenchymal Stromal Cells Revealed by Specific In Vitro Culture Conditions

Human menstrual blood-derived mesenchymal stromal cells (MenSCs) have become not only an important source of stromal cells for cell therapy but also a cellular source for neurologic disorders in vitro modeling. By using culture protocols originally developed in our laboratory, we show that MenSCs can be converted into floating neurospheres (NSs) using the Fast-N-Spheres medium for 24-72 h and can be transdifferentiated into functional dopaminergic-like (DALNs, ~ 26% TH + /DAT + flow cytometry) and cholinergic-like neurons (ChLNs, ~ 46% ChAT + /VAChT flow cytometry) which responded to dopamine- and acetylcholine-triggered neuronal Ca²⁺ inward stimuli when cultured with the NeuroForsk and the Cholinergic-N-Run medium, respectively in a timely fashion (i.e., 4-7 days). Here, we also report a direct transdifferentiation method to induce MenSCs into functional astrocyte-like cells (ALCs) by incubation of MenSCs in commercial Gibco® Astrocyte medium in 7 days. The MSC-derived ALCs (~ 59% GFAP + /S100β +) were found to respond to glutamate-induced Ca²⁺ inward stimuli. Altogether, these results show that MenSCs are a reliable source to obtain functional neurogenic cells to further investigate the neurobiology of neurologic disorders.

Solely aqueous formulation of hydrophobic cationic polymers for efficient gene delivery

Cationic polymers are promising gene delivery vectors due to their ability to bind and protect genetic material. The introduction of hydrophobic moieties into cationic polymers can further improve the vector efficiency, but common formulations of hydrophobic polymers involve harsh conditions such as organic solvents, impairing intactness and loading efficiency of the genetic material. In this study, a mild, aqueous formulation method for the encapsulation of high amounts of genetic material is presented. A well-defined pH-responsive hydrophobic copolymer, i.e. poly((n-butylmethacrylate)-co-(methylmethacrylate)-co-(2-(dimethylamino) ethylmethacrylate)), (PBMD) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Exploiting the pH-dependent solubility behavior of the polymer, stable pDNA loaded nanoparticles were prepared and characterized using analytical ultracentrifugation (AUC), cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). This novel formulation approach showed high transfection efficiencies in HEK293T cells, while requiring 5- to 10-fold less pDNA compared to linear polyethylenimine (LPEI), in particular at short incubation times and in serum-containing media. Furthermore, the formulation was successfully adopted for siRNA and mRNA encapsulation and the commercially approved polymer Eudragit® E(PO/100). Overall, the aqueous formulation approach, accompanied by a tailor-made hydrophobic polymer and detailed physicochemical and application studies, led to improved gene delivery vectors with high potential for further applications.

Viromers as carriers for mRNA-mediated expression of therapeutic molecules under inflammatory conditions

Therapeutic mRNA delivery has been described for several treatment options, such as vaccination and cancer immunotherapy. However, mRNA delivery has to be accompanied by the development and testing of suitable carrier materials due to the instability of mRNAs in human body fluids. In the present study, we investigated the ability of recently developed Viromers to deliver mRNAs in a classical inflammatory setting. We tested mRNAs coding for active components of preclinical (7ND) and approved (sTNF-RII) biologics, in vitro and in vivo. 7ND is an established blocker of the CCR2 axis, whereas sTNF-RII is the active component of the approved drug Etanercept. Viromer/mRNA complexes were transfected into murine macrophages in vitro. Protein expression was analysed using Luciferase reporter expression and mainly identified in spleen, blood and bone marrow in vivo. 7ND-mRNA delivery led to efficient blockage of monocytes infiltration in thioglycolate-induced peritonitis in mice, underlining the ability of Viromers to deliver a therapeutic mRNA cargo without overt toxicity. Therefore, we propose Viromer-based mRNA delivery as a suitable option for the treatment of inflammatory disorders beyond infusion of biological molecules.

Long non-coding RNA SLCO4A1-AS1 drives the progression of non-small-cell lung cancer by modulating miR-223-3p/IKKα/NF-κB signaling

Globally, lung cancer is known as a major cause of cancer-associated death and non-small-cell lung cancer (NSCLC) accounts for majority of all cases. Growing evidence has emerged that long non-coding RNAs (lncRNAs) act as vital regulatory molecules in various malignancies. Nevertheless, the function of SLCO4A1 antisense RNA 1(SLCO4A1-AS1) in NSCLC is vague. This study intended to investigate the biological role and probable regulatory mechanism of SLCO4A1-AS1 in NSCLC. qRT-PCR revealed that SLCO4A1-AS1 level was upregulated in NSCLC. Function assays manifested that silence of SLCO4A1-AS1 attenuated NSCLC cell proliferation, migration and invasion but promoted NSCLC cell apoptosis. Furthermore, we disclosed that SLCO4A1-AS1 activated NF-κB pathway in NSCLC, and that IKKα, an NF-κB pathway-related gene, possessed an enhanced level in NSCLC tissues and cells. Importantly, miR-223-3p bound with SLCO4A1-AS1 and IKKα. Further, SLCO4A1-AS1 competitively bound with miR-223-3p to increase IKKα expression, thereby activating NF-κB signaling pathway. In conclusion, SLCO4A1-AS1 drove NSCLC progression by activating NF-κB signaling pathway via sponging miR-223-3p to enhance IKKα expression. Thus, SLCO4A1-AS1 might be a promising biomarker for NSCLC treatment.

Nanoparticle Based Gene Therapy Approach: A Pioneering Rebellion in the Management of Psychiatric Disorders

The neuropsychiatric illnesses have been enigmatic, with no effective treatment to date. The complexity and heterogeneity of psychiatric disorders are daunting for the development of novel treatment modalities. The conventional treatment approaches are less effective and are associated with several side effects, thus creating the need for the development of more innovative strategies. Since psychiatric disorders are known to exhibit genetic linkage, gene therapy has created an interest among the researchers worldwide. The delivery of nucleic acids is a complex process requiring the transport of genetic material across various intracellular and extracellular barriers to reach the target cells eliciting the transfection process. Therefore, the identification or development of the delivery system for nucleic acid delivery still remains the challenge. Viral vectors are quite effective but are associated with toxicity and side effects. With the rapid advancement in the field of nanotechnology, nanosized materials were identified to be the perfect candidate for nonviral vectors in gene delivery. The biggest advantage of nanoparticles is that their surface can be engineered in many possible ways to deliver the drugs directly to the target site. Although gene therapy has already been established as an innovative treatment modality for several neurological diseases, its use in psychiatry still warrants more investigations for its translation into clinical use. The present manuscript discusses the prospects of gene therapy in psychiatric disorders, their benefits, and pitfalls. The review embarks upon the importance of nanoparticle-based gene therapy for effective management of psychiatric disorders.

Subcellular diversion of cholesterol by gain- and loss-of-function mutations in PMP22

Abnormalities of the peripheral myelin protein 22 (PMP22) gene, including duplication, deletion and point mutations are a major culprit in Type 1 Charcot-Marie-Tooth (CMT) diseases. The complete absence of PMP22 alters cholesterol metabolism in Schwann cells, which likely contributes to myelination deficits. Here, we examined the subcellular trafficking of cholesterol in distinct models of PMP22-linked neuropathies. In Schwann cells from homozygous Trembler J (TrJ) mice carrying a Leu16Pro mutation, cholesterol was retained with TrJ-PMP22 in the Golgi, alongside a corresponding reduction in its plasma membrane level. PMP22 overexpression, which models CMT1A caused by gene duplication, triggered cholesterol sequestration to lysosomes, and reduced ATP-binding cassette transporter-dependent cholesterol efflux. Conversely, lysosomal targeting of cholesterol by U18666A treatment increased wild type (WT)-PMP22 levels in lysosomes. Mutagenesis of a cholesterol recognition motif, or CRAC domain, in human PMP22 lead to increased levels of PMP22 in the ER and Golgi compartments, along with higher cytosolic, and lower membrane-associated cholesterol. Importantly, cholesterol trafficking defects observed in PMP22-deficient Schwann cells were rescued by WT but not CRAC-mutant-PMP22. We also observed that myelination deficits in dorsal root ganglia explants from heterozygous PMP22-deficient mice were improved by cholesterol supplementation. Collectively, these findings indicate that PMP22 is critical in cholesterol metabolism, and this mechanism is likely a contributing factor in PMP22-linked hereditary neuropathies. Our results provide a basis for understanding how altered expression of PMP22 impacts cholesterol metabolism.

Mesenchymal stem cells promote mesenteric vasodilation through hydrogen sulfide and endothelial nitric oxide

Mesenteric ischemia is a devastating process that can result in intestinal necrosis. Mesenchymal stem cells (MSCs) are becoming a promising treatment modality. We hypothesized that 1) MSCs would promote vasodilation of mesenteric arterioles, 2) hydrogen sulfide (H₂S) would be a critical paracrine factor of stem cell-mediated vasodilation, 3) mesenteric vasodilation would be impaired in the absence of endothelial nitric oxide synthase (eNOS) within the host tissue, and 4) MSCs would improve the resistin-to-adiponectin ratio in mesenteric vessels. H₂S was measured with a specific fluorophore (7-azido-3-methylcoumarin) in intact MSCs and in cells with the H₂S-producing enzyme cystathionine β synthase (CBS) knocked down with siRNA. Mechanical responses of isolated second- and third-order mesenteric arteries (MAs) from wild-type and eNOS knockout (eNOSKO) mice were monitored with pressure myography, after which the vessels were snap frozen and later analyzed for resistin and adiponectin via multiplex beaded assay. Addition of MSCs to the myograph bath significantly increased vasodilation of norepinephrine-precontracted MAs. Knockdown of CBS in MSCs decreased H₂S production by MSCs and also decreased MSC-initiated MA dilation. MSC-initiated vasodilation was further reduced in eNOSKO vessels. The MA resistin-to-adiponectin ratio was higher in eNOSKO vessels compared with wild-type. These results show that MSC treatment promotes dilation of MAs by an H₂S-dependent mechanism. Furthermore, functional eNOS within the host mesenteric bed appears to be essential for maximum stem cell therapeutic benefit, which may be attributable, in part, to modifications in the resistin-to-adiponectin ratio.NEW & NOTEWORTHY Stem cells have been shown to improve survival, mesenteric perfusion, and histological injury scores following intestinal ischemia. These benefits may be due to the paracrine release of hydrogen sulfide. In an ex vivo pressure myography model, we observed that mesenteric arterial dilation improved with stem cell treatment. Hydrogen sulfide release from stem cells and endothelial nitric oxide synthase within the vessels were critical components of optimizing stem cell-mediated mesenteric artery dilation.

Efficient and innocuous delivery of small interfering RNA to microglia using an amphiphilic dendrimer nanovector

Aim: Alterations of microglia, the brain-resident macrophages, are associated with numerous brain pathologies. Genetic manipulation of microglia in diseases using small interfering RNA (siRNA) is hampered by the lack of safe and efficient siRNA delivery methods. We assessed the amphiphilic dendrimer (AD) for functional siRNA delivery and gene knockdown in primary microglia. Materials & methods: We characterized the ability of AD to form nanoparticles with siRNA, and studied their size, surface potential, cell uptake and gene silencing in rodent microglia. Results: AD effectively delivered siRNA to primary microglia and decreased target gene and protein expression, leading to transcriptomic changes without affecting basal microglial functions. Conclusion: The dendrimer AD promises to be an innocuous carrier for siRNA delivery into microglia.

PMP22 Regulates Cholesterol Trafficking and ABCA1-Mediated Cholesterol Efflux

The absence of functional peripheral myelin protein 22 (PMP22) is associated with shortened lifespan in rodents and severe peripheral nerve myelin abnormalities in several species including humans. Schwann cells and nerves from PMP22 knock-out (KO) mice show deranged cholesterol distribution and aberrant lipid raft morphology, supporting an unrecognized role for PMP22 in cellular lipid metabolism. To examine the mechanisms underlying these abnormalities, we studied Schwann cells and nerves from male and female PMP22 KO mice. Whole-cell current-clamp recordings in cultured Schwann cells revealed increased membrane capacitance and decreased membrane resistance in the absence of PMP22, which was consistent with a reduction in membrane cholesterol. Nerves from PMP22-deficient mice contained abnormal lipid droplets, with both mRNA and protein levels of apolipoprotein E (apoE) and ATP-binding cassette transporter A1 (ABCA1) being highly upregulated. Despite the upregulation of ABCA1 and apoE, the absence of PMP22 resulted in reduced localization of the transporter to the cell membrane and diminished secretion of apoE. The absence of PMP22 also impaired ABCA1-mediated cholesterol efflux capacity. In nerves from ABCA1 KO mice, the expression of PMP22 was significantly elevated and the subcellular processing of the overproduced protein was aberrant. In wild-type samples, double immunolabeling identified overlapping distribution of PMP22 and ABCA1 at the Schwann cell plasma membrane and the two proteins were coimmunoprecipitated from Schwann cell and nerve lysates. Together, these results reveal a novel role for PMP22 in regulating lipid metabolism and cholesterol trafficking through functional interaction with the cholesterol efflux regulatory protein ABCA1.SIGNIFICANCE STATEMENT Understanding the subcellular events that underlie abnormal myelin formation in hereditary neuropathies is critical for advancing therapy development. Peripheral myelin protein 22 (PMP22) is an essential peripheral myelin protein because its genetic abnormalities account for ∼80% of hereditary neuropathies. Here, we demonstrate that in the absence of PMP22, the cellular and electrophysiological properties of the Schwann cells' plasma membrane are altered and cholesterol trafficking and lipid homeostasis are perturbed. The molecular mechanisms for these abnormalities involve a functional interplay among PMP22, cholesterol, apolipoprotein E, and the major cholesterol-efflux transporter protein ATP-binding cassette transporter A1 (ABCA1). These findings establish a critical role for PMP22 in the maintenance of cholesterol homeostasis in Schwann cells.

Reaching for the Stars in the Brain: Polymer-Mediated Gene Delivery to Human Astrocytes

Astrocytes, the "star-shaped" glial cells, are appealing gene-delivery targets to treat neurological diseases due to their diverse roles in brain homeostasis and disease. Cationic polymers have successfully delivered genes to mammalian cells and hence present a viable, non-immunogenic alternative to widely used viral vectors. In this study, we investigated the gene delivery potential of a series of arginine- and polyethylene glycol-modified, siloxane-based polyethylenimine analogs in primary cultured human neural cells (neurons and astrocytes) and in mice. Plasmid DNAs encoding luciferase reporter were used to measure gene expression. We hypothesized that polyplexes with arginine would help in cellular transport of the DNA, including across the blood-brain barrier; polyethylene glycol will stabilize polyethylenimine and reduce its toxicity while maintaining its DNA-condensing ability. Polyplexes were non-toxic to human neural cells and red blood cells. Cellular uptake of polyplexes and sustained gene expression were seen in human astrocytes as well as in mouse brains post-intravenous-injections. The polyplexes also delivered and expressed genes driven by astrocyte-restricted glial fibrillary acidic protein promoters, which are weaker than viral promoters. To our knowledge, the presented work validates a biocompatible and effective polymer-facilitated gene-delivery system for both human brain cells and mice for the first time.

Construction of PLGA/JNK3-shRNA nanoparticles and their protective role in hippocampal neuron apoptosis induced by oxygen and glucose deprivation

C-Jun N-terminal kinase 3 (JNK3) activation plays an essential role in the pathophysiology of cerebral ischemia. However, to date, no specific interventions with good efficacy have been reported. Therefore, in this study, we constructed a PLGA/JNK3-shRNA nanoparticle and examined its effects on neuronal apoptosis in an in vitro model of cerebral ischemia (oxygen and glucose deprivation model, OGD model). Herein, three JNK3-specific siRNAs were designed and synthesized, and their effects on JNK mRNA transcription were investigated; the most efficacious JNK3-specific siRNA was selected for recombination of the GV107/JNK3-shRNA plasmid. The PLGA/JNK3-shRNA nanoparticle was constructed, and its surface characterizations were confirmed. The roles of PLGA/JNK3-shRNA in neuronal JNK3 mRNA transcription, protein expression and activation as well as cell apoptosis were examined in a rat hippocampal neuron OGD model and compared with those of Lipofectamine 2000-mediated JNK3-siRNA transfection. The recombinant plasmid GV107/JNK3-shRNA was successfully constructed using siRNA1928. The PLGA/JNK3-shRNA nanoparticles were prepared as a sphere with a complete shape and smooth surface. The particle was about 225.4 nm in diameter with an average drug loading of 36.9%. OGD can cause marked cell apoptosis, whereas PLGA/JNK3-shRNA exposure can partly inhibit apoptosis. Further analysis demonstrated that the levels of JNK3 mRNA and protein as well as their activation were suppressed by PLGA/JNK3-shRNA nanoparticles. Compared with JNK3-siRNA delivered by Lipofectamine-2000, PLGA/JNK3-shRNA nanoparticles induced more JNK3 mRNA and protein reduction and more anti-apoptotic effects. To conclude, the PLGA/JNK3-shRNA nanoparticles could achieve good effects on inhibiting JNK3 signaling and neuronal apoptosis, and their preparation was feasible.

C-Jun N-terminal kinase 3 (JNK3) activation plays an essential role in the pathophysiology of cerebral ischemia.

Magnetofection is superior to other chemical transfection methods in a microglial cell line

BACKGROUND

Microglia, the resident phagocytic cells of the brain, have recently been the subject of intense investigation given their role in pathology and normal brain physiology. In general, phagocytic cells are hard to transfect with plasmid DNA. The BV2 cell line is a murine cell line of microglial origin which is often used to study this cell type in vitro. Unfortunately, this microglial cell line is, like other phagocytic cells, resistant to transfection.

NEW METHOD

Magnetofection is a well-established transfection method that combines DNA with magnetic particles which, under the influence of a magnetic field, ensures a high concentration of particles in proximity of cultured cells. Only recently, Glial-Mag was specifically developed for efficient transfection of microglia and microglial cell lines.

RESULTS

Magnetofection with Glial-Mag yielded a transfection efficiency of 34.95% in BV2 cells, 24h after transfection with an eGFP-expressing plasmid. Efficient gene delivery caused a modest and short-lived cell activation (as measured by IL6 secretion) that ceased by 24h after transfection.

COMPARISON WITH EXISTING METHODS

Here we show that Glial-Mag magnetofection of BV2 cells yielded a significantly higher transfection efficiency (34.95%) compared to other chemical transfection methods including calcium-phoshate precipication (0.34%), X-tremeGENE (3.30%) and Lipofectamine 2000 (12.51%).

CONCLUSION

Transfection of BV2 cells using Glial-Mag magnetofection is superior compared to other chemical transfection methods and could be considered as the method of choice to chemically transfect microglial cell lines.

Destination Brain: the Past, Present, and Future of Therapeutic Gene Delivery

Neurological diseases and disorders (NDDs) present a significant societal burden and currently available drug- and biological-based therapeutic strategies have proven inadequate to alleviate it. Gene therapy is a suitable alternative to treat NDDs compared to conventional systems since it can be tailored to specifically alter select gene expression, reverse disease phenotype and restore normal function. The scope of gene therapy has broadened over the years with the advent of RNA interference and genome editing technologies. Consequently, encouraging results from central nervous system (CNS)-targeted gene delivery studies have led to their transition from preclinical to clinical trials. As we shift to an exciting gene therapy era, a retrospective of available literature on CNS-associated gene delivery is in order. This review is timely in this regard, since it analyzes key challenges and major findings from the last two decades and evaluates future prospects of brain gene delivery. We emphasize major areas consisting of physiological and pharmacological challenges in gene therapy, function-based selection of a ideal cellular target(s), available therapy modalities, and diversity of viral vectors and nanoparticles as vehicle systems. Further, we present plausible answers to key questions such as strategies to circumvent low blood-brain barrier permeability and most suitable CNS cell types for targeting. We compare and contrast pros and cons of the tested viral vectors in the context of delivery systems used in past and current clinical trials. Gene vector design challenges are also evaluated in the context of cell-specific promoters. Key challenges and findings reported for recent gene therapy clinical trials, assessing viral vectors and nanoparticles are discussed from the perspective of bench to bedside gene therapy translation. We conclude this review by tying together gene delivery challenges, available vehicle systems and comprehensive analyses of neuropathogenesis to outline future prospects of CNS-targeted gene therapies.