Brain-specific Delivery Research Articles

Phyto-Active Components Delivered through Lipid Nanodrug Carriers as a Promising Avenue for the Treatment of Alzheimer’s Disease: Their Present Status and Industrial Viability

Introduction: Present years have witnessed an unprecedented growth of Alzheimer’s disease (AD) with limited scope for conventional therapeutics. Plant-derived active components (PACs) are being widely utilized as alternate, compatible, efficacious, eco-friendly strategies to ameliorate therapeutic benefits in AD while minimizing toxic effects. However, delivery of PACs in the regular dosage form often faces challenges due to low stability and bioavailability, brainspecific delivery, dose-related toxic effects, etc., which can be subsided by experimentally fabricated Lipid Nano Drug Carriers (LNCs). The objective of this study is to provide a comprehensive, evidence-based review on recent progress in the PACs-loaded lipid nanocarriers (PLNs)-based therapeutic strategies for AD. Methods: For the study implementation, a systematic literature review was carried out from various scientific potential databases like Scopus, Pubmed, Web of Science, etc., and relevant evidence- based pre-clinical research data was pooled to draw conclusive outcomes. Results: LNCs are treated as promising avenues to effectively deliver various PACs into the brain due to their high lipophilicity with ultra-micron size and tunable surface features, which make them eligible to pass through the blood-brain barrier. Both passive and active targeting of PLNs has been explored to target AD by overcoming the off-target bio delivery problems. Conclusion: The review provided updated preclinical study-based data on the potentialities of PLNs in overcoming AD. Simultaneously, equal weightage was devoted to the issues faced beyond the laboratory in their successful technology transfer. The study would be beneficial in unveiling important insights into the implications of PLNs for their futuristic clinical applicability.

Brain Targeting Nanomedicines: Pitfalls and Promise.

Brain diseases are the most devastating problem among the world's increasingly aging population, and the number of patients with neurological diseases is expected to increase in the future. Although methods for delivering drugs to the brain have advanced significantly, none of these approaches provide satisfactory results for the treatment of brain diseases. This remains a challenge due to the unique anatomy and physiology of the brain, including tight regulation and limited access of substances across the blood-brain barrier. Nanoparticles are considered an ideal drug delivery system to hard-to-reach organs such as the brain. The development of new drugs and new nanomaterial-based brain treatments has opened various opportunities for scientists to develop brain-specific delivery systems that could improve treatment outcomes for patients with brain disorders such as Alzheimer's disease, Parkinson's disease, stroke and brain tumors. In this review, we discuss noteworthy literature that examines recent developments in brain-targeted nanomedicines used in the treatment of neurological diseases.

Efficient Delivery of FMR1 across the Blood Brain Barrier Using AAVphp Construct in Adult FMR1 KO Mice Suggests the Feasibility of Gene Therapy for Fragile X Syndrome.

Background Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability and autism. Gene therapy may offer an efficient method to ameliorate the symptoms of this disorder. Methods An AAVphp.eb-hSyn-mFMR1IOS7 vector and an empty control were injected into the tail vein of adult Fmr1 knockout (KO) mice and wildtype (WT) controls. The KO mice were injected with 2 × 1013 vg/kg of the construct. The control KO and WT mice were injected with an empty vector. Four weeks following treatment, the animals underwent a battery of tests: open field, marble burying, rotarod, and fear conditioning. The mouse brains were studied for levels of the Fmr1 product FMRP. Results: No significant levels of FMRP were found outside the CNS in the treated animals. The gene delivery was highly efficient, and it exceeded the control FMRP levels in all tested brain regions. There was also improved performance in the rotarod test and partial improvements in the other tests in the treated KO animals. Conclusion: These experiments demonstrate efficient, brain-specific delivery of Fmr1 via peripheral administration in adult mice. The gene delivery led to partial alleviation of the Fmr1 KO phenotypical behaviors. FMRP oversupply may explain why not all behaviors were significantly affected. Since AAV.php vectors are less efficient in humans than in the mice used in the current experiment, studies to determine the optimal dose using human-suitable vectors will be necessary to further demonstrate feasibility.

Saponins-uptake and Targeting Issues for Brain-specific Delivery for Enhanced Cell Death Induction in Glioblastoma

Abstract: Saponins represent a category of diverse, natural glycoside molecules that belong to the triterpenoid or the steroid class. They vary in terms of their solubility and permeability characteristics and are classifiable based on the biopharmaceutics classification system. They have drug delivery potential as surfactants that can solubilize cholesterol in the plasma membrane of tumorigenic cells. Glioblastoma is an important malignancy that can aggressively afflict the brain of humans with a poor prognosis. Glioblastoma Stem Cells (GSCs), are an important subset of cancer cells and are major determinants for drug resistance and tumour relapse. These cells are quiescent and have been known to survive current therapeutic strategies. Certain saponins have shown potential to eliminate glioblastoma cells in a variety of model systems and hence provide a sound scientific basis for their development as a “stand-alone” drug or as part of a drug combination (from the existing arsenal of drugs) developed for the treatment of glioblastoma. However, due to their reactogenicity towards the immune system and hemolytic potential, selective delivery to the tumorigenic site is essential. Hence, nano-formulations (liposome/emulsion-based delivery systems/nano-structured lipid and calix[n]arenes-based carriers) and variants that are resistant to saponin may serve as delivery tools that can be functionalized to improve the selectivity. It is necessary to develop/validate/refine in vitro higher order models that replicate the features of the glioma microenvironment (BBB/BTB). Reproducible validation of the model as well as the drug/delivery system will help in the development of formulations that can augment cell death in this recalcitrant brain tumour.

Formulation and cognitive evaluation of self-assembled phosphatidylserine-chitosan nanoparticles of lycopene, an innovative technique to lessen STZ-induced oxidative stress: A vital persuader of major neurological diseases

The present study deals with the encapsulation and brain-specific targeting of Lycopene (LYC) as Polysorbate-80 (P-80) coated Phosphatidylserine-chitosan self-assembled nanoparticles (P-80-LYC-PSCNP), with an approach to reduce oxidative stress which is rationalized as a major cause of neurological disease. P-80-LYC-PSCNP was formulated by using the injection technique for self-assembly of Phosphatidylserine and chitosan, applying P-80 coating for surface modification and were assessed for their morphology and physicochemical attributes. The efficiency of LYC liberated from P-80-LYC-PSCNP was determined in Streptozotocin-induced Oxidative stress Model (SOSM); cognitively by behavioral despair-test and biochemically by enzymatic assays at 5 mg/kg LYC-equivalent dose. P-80-LYC-PSCNP were formulated as stable (ζ = 3.89 mV) spherical, regular (≈220 nm), and homogenous entities. It demonstrated a total 76.89% LYC in-vitro release during 28 hrs and shown efficacy for brain-specific delivery with a relative bioavailability of 20.4, Cmax 4.6 times, and 2.5 times swifter than normal LYC. After 28 days, it shortened immobility time by 72.57 ± 8.12 s (P < 0.01) against STZ-control (134.58 ± 13.85 s, P < 0.001). It also improved the antioxidant enzymatic functioning of CAT, SOD, and GPx by 7.90 ± 0.45 Δ240/min/mgP (P < 0.05), 32.50 ± 1.70 U/mgP (P < 0.01), and 59.40 ± 3.70 U/mgP (P < 0.01) respectively against STZ-control which showed 3.05 ± 0.80 Δ240/min/mgP (P < 0.05), 15.20 ± 3.10 U/mgP (P < 0.05), and 25.15 ± 3.05 U/mgP at 5 mg/kg LYC-equivalent dose respectively. P-80-LYC-PSCNP was successfully formulated, analyzed and had delivered Lycopene (5 mg/kg) by trespassing the BBB with improved pharmacokinetics. It alleviated the experimental Streptozotocin-induced Oxidative stress in turn improving behavioral and cognitive anomalies, while enhancing the antioxidant-related activity of enzymes.

Intranasal 17β-Estradiol Modulates Spatial Learning and Memory in a Rat Model of Surgical Menopause.

Exogenously administered 17β-estradiol (E2) can improve spatial learning and memory, although E2 also exerts undesired effects on peripheral organs. Clinically, E2 has been solubilized in cyclodextrin for intranasal administration, which enhances brain-specific delivery. Prior work shows that the cyclodextrin structure impacts region-specific brain distribution of intranasally administered small molecules. Here, we investigated (1) cyclodextrin type-specific modulation of intranasal E2 brain distribution, and (2) cognitive and peripheral tissue effects of intranasal E2 in middle-aged ovariectomized rats. First, brain and peripheral organ distribution of intranasally administered, tritiated E2 was measured for E2 solubilized freely or in one of four cyclodextrin formulations. The E2-cyclodextrin formulation with greatest E2 uptake in cognitive brain regions versus uterine horns was then compared to free E2 on learning, memory, and uterine measures. Free E2 improved spatial reference memory, whereas E2-cyclodextrin impaired spatial working memory compared to their respective controls. Both E2 formulations increased uterine horn weights relative to controls, with E2-cyclodextrin resulting in the greatest uterine horn weight, suggesting increased uterine stimulation. Thus, intranasal administration of freely solubilized E2 is a strategic delivery tool that can yield a cognitively beneficial impact of the hormone alongside decreased peripheral effects compared to intranasal administration of cyclodextrin solubilized E2.

A review: Brain specific delivery

A review: Brain specific delivery

A review: Brain specific delivery

The overall prevalence rate for CNS pathology has demonstrated that approximately more than one billion people are undergoing from disorders of central nervous system. The most distressing fact about delivery of drugs to the CNS is the presence of blood brain barrier that have a tendency to impair the drug distribution and denotes the major impediment for the development of CNS drugs. Neuropeptides and many drugs which are hydrophilic in nature possibly will encompass the intricacy while passing the blood brain barrier. The net amount of delivered drug (medicinal agent) and its capability to gain access to the pertinent target sites are the main considering points for CNS drug development. Brain targeted drug delivery to the brain is valuable in the diseases of brain. (Alzheimer’s diseases, meningitis, brain abscess, epilepsy, multiple sclerosis, neuromylitis optica, sleeping disorders etc). Whereby high concentration can be gained with lesser side effects that occur because of release of drugs. The simplest method of targeting to brain is to obtain a therapeutic. Brain targeting systems to remain in the brain region by crossing BBB and hence significantly helps in increasing therapeutic activity. There is an increasing attraction towards brain targeting and sue to its immense application in the treatment of various CNS diseases because mostly drugs are unable to cross the BBB. This review article discuss one of the novel technology “nanotechnology” and other aspects that has been developed to target the brain and possess various clinical benefits such as reduced drug dose, less side effects, non-invasive routed, and better patient compliance.

Mesenchymal Stem Cell-Derived Exosomes for Treatment of Autism Spectrum Disorder.

Recent breakthroughs in the field of stem cell therapy have brought hope to the treatment of mental diseases. Animal experiments and clinical studies have shown that transplantation of mesenchymal stem cells (MSCs) has a positive effect on the treatment of autism spectrum disorder (ASD). However, the therapeutic efficacy of the MSC transplants was primarily associated with the signals and molecules secreted by the MSCs. Exosomes, for example, the secreted organelles from MSCs, carry bioactive molecules of the MSCs that are essential for the therapeutic effects in ASD treatment. This then inspires us to explore the intranasal delivery of MSC exosomes to brain tissues for the treatment of ASD. Exosomes from human umbilical cord mesenchymal stem cells (hUC-MSCs) that efficiently enter the brain tissue through the intranasal route restore the social ability of the mice and correct the repeated stereotyped behaviors and other abnormal phenotypes in the offspring of valproic acid (VPA)-treated mice, which show autism-like symptoms. The therapeutic efficacy can be attributed at least partially to the anti-inflammatory effect of the MSC exosomes. This work thereby reports brain-specific delivery of hUC-MSC exosomes, as a cell-free therapy to relieve autism-related phenotypes, providing a promising direction for the treatment of mental development disorders.

Bacosides Encapsulated in Lactoferrin Conjugated PEG-PLA-PCL-OH Based Polymersomes Act as Epigenetic Modulator in Chemically Induced Amnesia.

The present study demonstrates the epigenetic mechanisms underlying the effect of Bacoside rich extract of Bacopa monniera-a nootropic herb, on scopolamine treated amnesic mice conferred via chromatin modifying enzymes. The focus of the work was to elucidate the modulation of the chromatin modifying enzymes: DNMT1, DNMT3a, DNMT3b, HDAC2, HDAC5 and CPB in scopolamine induced amnesic mice after treatment with bacoside rich extract of Bacopa monniera (BA) and BA encapsulated in lactoferrin conjugated PEG-PLA-PCL-OH based polymersomes (BAN). We observed remarkable difference between the results obtained after the treatment with BA and BAN. Interestingly BAN was found to be more efficient in downregulating DNA methylation and histone chain deacetylation. Scopolamine treatment showed up-regulation of DNMT1 expression in qRT-PCR by 3.14-fold as compared to the control, which was considerably decreased by 1.5-fold after treatment with BA and remarkably decreased 0.11-fold by BAN treatment. Scopolamine treatment up-regulated the expression of DNMT3a by 1.6-fold while for DNMT3b by 3.13-fold. In DNMT3a and DNMT3b the fold change decreased to 0.64 and 0.76 after BA treatment, whereas the BAN treatment further down-regulated to 0.32- and 0.63-fold, respectively. Similarly scopolamine up-regulated HDAC2 and HDAC5 by 3.12 fold and 3.64-fold, respectively. BA treatment reversed the changes by reducing HDAC2 mRNA to 0.89-fold and HDAC5 mRNA 0.83-fold. BAN further reduced expression of HDAC2 further to 0.39-fold and HDAC5 to 0.31-fold. On the other hand scopolamine down-regulated CBP mRNA expression by 0.28-fold and increased by 1.09 after BA treatment. BAN significantly increased the CPB expression by 1.65-fold as compared to BA treatment. These findings were consolidated by DNMT and HDAC enzyme activity assay, methylation in the promoter region of the memory related genes: ARC and BDNF and Dot blot assay for DNA methylation. The percent activity increase of DNMT and HDAC after scopolamine administration was 375.74 and 240.90 respectively. After treatment with BA the downfall in percent activity was observed as 167.99 in DMNT and 130.57 in HDAC. BAN treatment further decreased the percent enzyme activity of DNMT and HDAC significantly by 30.0 and 61.81 respectively. The potency of BAN in reversing the epigenetic changes of scopolamine induced amnesic mouse brain, can be attributed to the brain specific delivery of BA through polymersomes which are able to cross the blood brain barrier (BBB) via receptor mediated endocytosis.

Accessing the Blood-Brain Barrier to Treat Brain Disorders

:Crossing the blood-brain barrier (BBB) and treating brain disorders by delivering therapeutic agents to specific regions of the brain is a challenge. The BBB, naturally evolved, protective physiological barrier acts as a selective permeable membrane in such a way that it allows only nonionic molecules and molecules of low molecular weight to pass through. Treating brain tumor has become a great challenge as the drug molecules of larger size are not able to cross the BBB and reach the target site. The incompetence of techniques for brain-specific delivery of therapeutic molecules has led researchers to increasingly explore the diagnosis and treatment of disorders incurable with present techniques. This article is to discuss the various techniques or methods to deliver drugs to the brain crossing the BBB.

Disrupted folate metabolism with anesthesia leads to myelination deficits mediated by epigenetic regulation of ERMN.

BackgroundExposure to anesthetics during early life may impair cognitive functions. However, the underlying mechanisms remain largely unknown. We set out to determine effects of sevoflurane anesthesia on folate metabolism and myelination in young non-human primates, mice and children.MethodsYoung rhesus macaque and mice received 2.5 to 3% sevoflurane daily for three days. DNA and RNA sequencing and immunohistochemistry among others were used in the studies. We performed unbiased transcriptome profiling in prefrontal cortex of rhesus macaques and mice after the sevoflurane anesthesia. We constructed a brain blood barrier-crossing AAV-PHP.EB vector to harbor ERMN expression in rescue studies. We measured blood folate levels in children after anesthesia and surgery.FindingsWe found that thymidylate synthase (TYMS) gene was downregulated after the sevoflurane anesthesia in both rhesus macaque and mice. There was a reduction in blood folate levels in children after the anesthesia and surgery. Combined with transcriptome and genome-wide DNA methylation analysis, we identified that ERMN was the primary target of the disrupted folate metabolism. Myelination was compromised by the anesthesia in the young mice, which was rescued by systematic administration of folic acid or expression of ERMN in the brain through brain-specific delivery of the adeno-associated virus. Moreover, folic acid and expression of ERMN alleviated the cognitive impairment caused by the sevoflurane anesthesia in the mice.InterpretationGeneral anesthesia leads to disrupted folate metabolism and subsequently defects in myelination in the developmental brain, and ERMN is the important target affected by the anesthesia via epigenetic mechanisms.

Disrupted Folate Metabolism with Anesthesia Leads to Myelination Deficits Mediated by Epigenetic Regulation of ERMN

Objective: Anesthetics during early life stages may impair cognitive and emotional functions, of which the underlying molecular mechanisms remain largely unknown. Methods: Here we performed the unbiased transcriptome profiling in prefrontal cortex of both non-human primates and mice after anesthesia. We also constructed a brain blood barrier (BBB)-crossing AAV-PHP.EB vector to harbor GFP or ERMN expression cassette. Findings: We found that the thymidylate synthase gene (TYMS), a critical gene implicated in folate metabolism, was significantly downregulated after multiple anesthesia in both non-human primates and mice. Hereby, we examined the metabolites in plasma of patients with anesthesia and surprisingly found that blood folate levels significantly decreased after surgeries under general anesthesia in children. Combined with transcriptome and genome-wide DNA methylation analysis, we identified that ERMN was the primary target of the disrupted folate metabolism. We further showed that myelination in brain during early postnatal stage was indeed compromised by the anesthesia in mice, which was fully rescued by systematic administration of folic acid or expression of ERMN in the brain through brain-specific delivery of adeno-associated virus. Notably, administration of folic acid and ERMN remarkably alleviated the cognitive impairment of mice caused by the anesthesia during early postnatal stages. Interpretation: This study indicates that anesthesia during early the postnatal period leads to disrupted folate metabolism and subsequently defects in myelination in the young brain, and ERMN is the key target gene affected by anesthesia via epigenetic mechanisms. Clinical Trial Registration: NCT03746340 Funding Statement: This work was mainly supported by NSFC Grants (#81571028, # 81771132, #31625013, #91732302) Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: The study protocol was approved by the Human Research Ethics Committee of Shanghai 9th People’s Hospital and Shanghai Jiao Tong University in Shanghai, P. R. China SH9H-2018-T53-2. The animal studies were performed according to the guidelines and regulations of the Institute of Laboratory Animal Science, Peking Union Medical College and Chinese Academy of Medical Science (Peking, China). Efforts were made to minimize the number of animals in the studies. The use of rhesus macaque in research at Institute of Laboratory Animal Science (Peking, China) was approved by Institutional Animal Care and Use Committee (Protocol number #XC17001).

Dual-targeting for brain-specific drug delivery: synthesis and biological evaluation

Ibuprofen is one of the most potent non-steroid anti-inflammatory drugs (NSAIDs) and plays an important role in the treatment of neurodegenerative diseases. However, its poor brain penetration and serious side effects at therapeutic doses, has hindered its further application. Thus, it is of great interest to develop a carrier-mediated transporter (CMT) system that is capable of more efficiently delivering ibuprofen into the brain at smaller doses to treat neurodegenerative diseases. In this study, a dual-mediated ibuprofen prodrug modified by glucose (Glu) and vitamin C (Vc) for central nervous system (CNS) drug delivery was designed and synthesized in order to effectively deliver ibuprofen to brain. Ibuprofen could be released from the prepared prodrugs when incubated with various buffers, mice plasma and brain homogenate. Also, the prodrug showed superior neuroprotective effect in vitro and in vivo than ibuprofen. Our results suggest that chemical modification of therapeutics with warheads of glucose and Vc represents a promising and efficient strategy for the development of brain-targeting prodrugs by utilizing the endogenous transportation mechanism of the warheads.

Pyrilamine-sensitive proton-coupled organic cation (H+/OC) antiporter for brain-specific drug delivery

Blood-brain barrier (BBB) represents the greatest challenge that hampers therapeutic molecules entering the brain. Here, we described a novel brain-specific delivery strategy targeting to pyrilamine-sensitive H+/OC antiporter to facilitate therapeutic molecules cross the BBB and penetrate into the brain. In this study, four cyclic tertiary amines were selected as the brain-targeting moieties to modify naproxen (NP), a non-steroidal anti-inflammatory drug. The obtained NP conjugates displayed cell uptake efficiencies over 144-fold higher than that of unmodified NP in endothelial cells. The cell uptake process of the conjugates was primarily driven by pyrilamine-sensitive H+/OC antiporter in a pH-dependent, Na+-independent, and membrane potential-independent pathway, which could be further inhibited by pyrilamine, propranolol, and imipramine. Moreover, the NP conjugates showed significantly higher AUC0−t and Cmax in the brain compared with unmodified NP, and significantly higher accumulation than NP in the in situ brain perfusion study. Also, the conjugates showed superior neuroprotective effect in vitro and in vivo. Thus, the chemical modification of therapeutics with a cyclic tertiary amine moiety represents a promising and efficient strategy for brain-specific drug delivery via pyrilamine-sensitive H+/OC antiporter.

Nanoparticles as a Carrier System for Drug Delivery Across Blood Brain Barrier.

Brain, the centre of the nervous system and an integral part the body, is protected by two anatomical and physiological barriers- Blood-Brain Barrier (BBB) and Blood-Cerebrospinal Fluid Barrier (BCSFB). Blood-Brain Barrier is a very complex and highly organized multicellular structure that shields the brain from harmful substances and invading organisms from the bloodstream and thus offering protection against various brain diseases and injuries. However, it also impede the effective delivery of drug to the brain, thus, preventing treatment of numerous neurological disorders. Even though various traditional approaches such as Intra-Cerebro-Ventricular (ICV) injection, use of implants, disruption of BBB and use of prodrugs have achieved some success in overcoming these barriers, researchers are continuously working for promising alternatives for improved brain drug delivery. Recent breakthroughs in the field of nanotechnology provide an appropriate solution to problems associated with these delivery approaches and thus can be effectively used to treat a wide variety of brain diseases. Thus, nanotechnology promises to bring a great future to the individuals with various brain disorders. This review provides a brief overview of various brain drug delivery approaches along with limitations. In addition, the significance of nanoparticles as drug carrier systems for effective brain specific drug delivery has been highlighted. To show the complexity of the problems to be overcome for improved brain drug delivery, a concise intercellular classification of the BBB along with general transport routes across it is also included.

Optical barcoding of PLGA for multispectral analysis of nanoparticle fate in vivo

Understanding of the mechanisms by which systemically administered nanoparticles achieve delivery across biological barriers remains incomplete, due in part to the challenge of tracking nanoparticle fate in the body. Here, we develop a new approach for “barcoding” nanoparticles composed of poly(lactic-co-glycolic acid) (PLGA) with bright, spectrally defined quantum dots (QDs) to enable direct, fluorescent detection of nanoparticle fate with subcellular resolution. We show that QD labeling does not affect major biophysical properties of nanoparticles or their interaction with cells and tissues. Live cell imaging enabled simultaneous visualization of the interaction of control and targeted nanoparticles with bEnd.3 cells in a flow chamber, providing direct evidence that surface modification of nanoparticles with the cell-penetrating peptide TAT increases their biophysical association with cell surfaces over very short time periods under convective current. We next developed this technique for quantitative biodistribution analysis in vivo. These studies demonstrate that nanoparticle surface modification with the cell penetrating peptide TAT facilitates brain-specific delivery that is restricted to brain vasculature. Although nanoparticle entry into the healthy brain parenchyma is minimal, with no evidence for movement of nanoparticles across the blood-brain barrier (BBB), we observed that nanoparticles are able to enter to the central nervous system (CNS) through regions of altered BBB permeability – for example, into circumventricular organs in the brain or leaky vasculature of late-stage intracranial tumors. In sum, these data demonstrate a new, multispectral approach for barcoding PLGA, which enables simultaneous, quantitative analysis of the fate of multiple nanoparticle formulations in vivo.

A Simple Alternative to Stereotactic Injection for Brain Specific Knockdown of miRNA

MicroRNAs (miRNAs) are key regulators of gene expression. In the brain, vital processes like neurodevelopment and neuronal functions depend on the correct expression of microRNAs. Perturbation of microRNAs in the brain can be used to model neurodegenerative diseases by modulating neuronal cell death. Currently, stereotactic injection is used to deliver miRNA knockdown agents to specific location in the brain. Here, we discuss strategies to design antagomirs against miRNA with locked nucleotide modifications (LNA). Subsequently describe a method for brain specific delivery of antagomirs, uniformly across different regions of the brain. This method is simple and widely applicable since it overcomes the surgery, associated injury and limitation of local delivery in stereotactic injections. We prepared a complex of neurotropic, cell-penetrating peptide Rabies Virus Glycoprotein (RVG) with antagomir against miRNA-29 and injected through tail vein, to specifically deliver in the brain. The antagomir design incorporated features that allow specific targeting of the miRNA and formation of non-covalent complexes with the peptide. The knock-down of the miRNA in neuronal cells, resulted in apoptotic cell death and associated behavioural defects. Thus, the method can be used for acute models of neuro-degeneration through the perturbation of miRNAs.

A Simple Alternative to Stereotactic Injection for Brain Specific Knockdown of miRNA.

MicroRNAs (miRNAs) are key regulators of gene expression. In the brain, vital processes like neurodevelopment and neuronal functions depend on the correct expression of microRNAs. Perturbation of microRNAs in the brain can be used to model neurodegenerative diseases by modulating neuronal cell death. Currently, stereotactic injection is used to deliver miRNA knockdown agents to specific location in the brain. Here, we discuss strategies to design antagomirs against miRNA with locked nucleotide modifications (LNA). Subsequently describe a method for brain specific delivery of antagomirs, uniformly across different regions of the brain. This method is simple and widely applicable since it overcomes the surgery, associated injury and limitation of local delivery in stereotactic injections. We prepared a complex of neurotropic, cell-penetrating peptide Rabies Virus Glycoprotein (RVG) with antagomir against miRNA-29 and injected through tail vein, to specifically deliver in the brain. The antagomir design incorporated features that allow specific targeting of the miRNA and formation of non-covalent complexes with the peptide. The knock-down of the miRNA in neuronal cells, resulted in apoptotic cell death and associated behavioural defects. Thus, the method can be used for acute models of neuro-degeneration through the perturbation of miRNAs.

GLUTATHIONE CONJUGATED PLGA NANOPARTICLES FOR ENHANCED BRAIN TARGETED DELIVERY OF A FLUORESCENT MARKER

The objective of the study was to investigate the biodistribution behavior of a fluorescent marker encapsulated in polymeric colloidal nanoparticulate system comprised of PLGA [poly (lactide-co-glycolic acid)] and also to quantify the uptake of fluorescein sodium by brain following intra nasal administration of formulation in vivo. The PLGA nanoparticles were coupled with glutathione, an endogenous transporter, for improving the brain specific delivery of fluorescein sodium by exploring carbodiimide chemistry using EDAC [1-ethyl-3-(3-dimethylaminopropyl)carbodiimide] as linker. The optimized formulation was characterized for in vitro and ex vivo release of fluorescein sodium from the formulation. The mean particle diameter of optimized fluorescein sodium loaded PLGA nanoparticles was found to be 115.25 ± 6.8 and 141.63± 4.5 nm for glutathione conjugated PLGA nanoparticles. The results from in vitro, ex vivo and in vivo studies reveal the significant capability of glutathione in achieving successful brain delivery of PLGA nanoparticles.