Treatment Of CNS Diseases Research Articles

Magnetic brain targeting of naproxen-loaded polymeric micelles: pharmacokinetics and biodistribution study

The blood brain barrier is a major obstacle to the entry of the majority of CNS-active agents. In the present research, the potential of magnetic polymeric micelles (MPMs) for brain-targeting of naproxen was evaluated. The MPMs were made of methoxy poly(ethyleneglycol)-poly (caprolactone) copolymer and super paramagnetic iron oxide nanoparticles (SPIONs). To investigate the impact of particle size on the in vivo biofate of nanoparticles, MPMs with two different sizes were prepared. The prepared magnetic polymeric micelles had diameters of 137 ± 3.5 nm (MPM137) and 242 ± 6.2 nm (MPM242) and their surface charges were about −6.5 and − 4.5 mV, respectively. Pharmacokinetic and biodistribution of nanoparticles were characterized in rats using an external magnet of 0.4 Tesla field strength located on the skull of anesthetized animals. Significant differences in volumes of central as well as peripheral compartments were observed between both MPM formulations and free naproxen solution. After 8 h of administration, the brain concentration of naproxen was shown to be higher in the case of MPM137 in comparison with MPM242 and free drug. The findings revealed that the polymeric magnetic micelles with diameters smaller than 150 nm could be initially considered as a promising carrier to improve therapeutic agent accumulation in the brain for the treatment of CNS diseases.

Transcytosis to Cross the Blood Brain Barrier, New Advancements and Challenges.

The blood brain barrier (BBB) presents a formidable challenge to the delivery of drugs into the brain. Several strategies aim to overcome this obstacle and promote efficient and specific crossing through BBB of therapeutically relevant agents. One of those strategies uses the physiological process of receptor-mediated transcytosis (RMT) to transport cargo through the brain endothelial cells toward brain parenchyma. Recent developments in our understanding of intracellular trafficking and receptor binding as well as in protein engineering and nanotechnology have potentiated the opportunities for treatment of CNS diseases using RMT. In this mini-review, the current understanding of BBB structure is discussed, and recent findings exemplifying critical advances in RMT-mediated brain drug delivery are briefly presented.

Влияние антагонистов NMDA рецепторов разных типов на вызванные ответы пирамидных нейронов в срезах коры мозга крысы

The use of NMDA receptor antagonists for the treatment of CNS diseases is currently limited. This may be due to the lack of knowledge about the effects of antagonists on the functional properties of neurons since in vitro models do not fully reproduce the real pathophysiological processes. We studied the effects of NMDA receptor antagonists on properties of pyramidal neuron responses in the rat prefrontal cortex. A competitive antagonist APV (50 µM) and an ion channel blocker memantine (100 µM) did not produce significant effects on evoked EPSP. When the inhibitory transmission was suppressed by picrotoxin (50 µM), the extracellular stimulation caused prolonged membrane depolarization and generation a series of action potentials. APV decreased duration and amplitude of such responses. Memantine was active only when magnesium was excluded from the extracellular environment. The lack of effects of memantine can be explained by its competition with magnesium for the binding site within the ion channel. This work demonstrates that in order to predict the systemic effects of blockers on the functions of neurons and their excitability, it is necessary to use in vitro models in which the activation of NMDA receptors occurs in the presence of physiological concentrations of magnesium and without clamping of membrane potential.

Sex-specific differences in organic anion transporting polypeptide 1a4 (Oatp1a4) functional expression at the blood\u2013brain barrier in Sprague\u2013Dawley rats

BackgroundTargeting endogenous blood–brain barrier (BBB) transporters such as organic anion transporting polypeptide 1a4 (Oatp1a4) can facilitate drug delivery for treatment of neurological diseases. Advancement of Oatp targeting for optimization of CNS drug delivery requires characterization of sex-specific differences in BBB expression and/or activity of this transporter.MethodsIn this study, we investigated sex differences in Oatp1a4 functional expression at the BBB in adult and prepubertal (i.e., 6-week-old) Sprague–Dawley rats. We also performed castration or ovariectomy surgeries to assess the role of gonadal hormones on Oatp1a4 protein expression and transport activity at the BBB. Slco1a4 (i.e., the gene encoding Oatp1a4) mRNA expression and Oatp1a4 protein expression in brain microvessels was determined using quantitative real-time PCR and western blot analysis, respectively. Oatp transport function at the BBB was determined via in situ brain perfusion using [3H]taurocholate and [3H]atorvastatin as probe substrates. Data were expressed as mean ± SD and analyzed via one-way ANOVA followed by the post hoc Bonferroni t-test.ResultsOur results showed increased brain microvascular Slco1a4 mRNA and Oatp1a4 protein expression as well as increased brain uptake of [3H]taurocholate and [3H]atorvastatin in female rats as compared to males. Oatp1a4 expression at the BBB was enhanced in castrated male animals but was not affected by ovariectomy in female animals. In prepubertal rats, no sex-specific differences in brain microvascular Oatp1a4 expression were observed. Brain accumulation of [3H]taurocholate in male rats was increased following castration as compared to controls. In contrast, there was no difference in [3H]taurocholate brain uptake between ovariectomized and control female rats.ConclusionsThese novel data confirm sex-specific differences in BBB Oatp1a4 functional expression, findings that have profound implications for treatment of CNS diseases. Studies are ongoing to fully characterize molecular pathways that regulate sex differences in Oatp1a4 expression and activity.

Development of Noninvasive Drug Delivery Systems to the Brain for the Treatment of Brain/Central Nervous System Diseases

In general, the blood-brain barrier (BBB) poses a major challenge to drug development efforts targeting brain/central nervous system (CNS) diseases, since it limits the distribution of systemically administered therapeutics to the brain/ CNS. Therefore, the development of effective strategies for enhancing drug delivery to the brain has been a topic of great interest in both the clinical and pharmaceutical fields. Intranasal administration has been noted as a method for noninvasive delivery of a drug to the brain/CNS by bypassing the BBB via the "nose-to-brain" route. This nose-to-brain delivery system has the potential to be highly versatile, and a combination of this system with new drugs and siRNA shows promise in the treatment of CNS diseases. Cell-penetrating Tat peptide-modified block copolymer micelles have the potential for improving mucosal permeability and nose-to-brain transport efficiency. In addition, nano-sized drug carriers can improve nose-to-brain delivery through their ability to increase the stability of encapsulated drugs against biological degradation in the nasal cavity and brain/CNS. In this review, we introduce the assessment of and mechanisms for delivery to the brain after intranasal drug/siRNA administration with our cell-penetrating peptide-modified nano-sized polymer micelles. Our findings show that the use of polymer micelles with surface modification by cell-penetrating peptides for intranasal administration enables the noninvasive delivery of therapeutic agents to the brain/CNS by increasing the nose-to-brain transfer of the drug or siRNA administered from the nasal cavity.

A Rationally Engineered Capsid Variant of AAV9 for Systemic CNS-Directed and Peripheral Tissue-Detargeted Gene Delivery in Neonates

Adeno-associated virus (AAV) has provided the gene therapy field with the most powerful in vivo gene delivery vector to realize safe, efficacious, and sustainable therapeutic gene expression. Because many clinically relevant properties of AAV-based vectors are governed by the capsid, much research effort has been devoted to the development of AAV capsids for desired features. Here, we combine AAV capsid discovery from nature and rational engineering to report an AAV9 capsid variant, designated as AAV9.HR, which retains AAV9’s capability to traverse the blood-brain barrier and transduce neurons. This variant shows reduced transduction in peripheral tissues when delivered through intravascular (IV) injection into neonatal mice. Therefore, when IV AAV delivery is used to treat CNS diseases, AAV9.HR has the advantage of mitigating potential off-target effects in peripheral tissues compared to AAV9. We also demonstrate that AAV9.HR is suitable for peripheral tissue-detargeted CNS-directed gene therapy in a mouse model of a fatal pediatric leukodystrophy. In light of recent success with profiling diversified natural AAV capsid repertoires and the understanding of AAV capsid sequence-structure-function relationship, such a combinatory approach to AAV capsid development is expected to further improve vector targeting and expand the vector toolbox for therapeutic gene delivery.

Recent Advances in Transcranial Focused Ultrasound (FUS) Triggered Brain Delivery.

Successful delivery of therapeutic agents in the brain is very challenging, which makes treatment of various brain disorders very difficult. One of the major causes of this difficulty is the presence of physiological barriers in the brain like blood brain barrier (BBB) and blood cerebrospinal fluid (CSF) barrier. These barriers are very specific and restrict the entry of water soluble agents and ionized molecule. The current article focuses on the transcranial route, transcranial focused ultrasound (FUS), and the techniques involved in transcranial focused ultrasound (FUS) delivery and recent updates of this system. The study describes that the FUS in conjunction with various other techniques opens the BBB very effectively. The administration of therapeutic agent using various FUS techniques opens a new perspective in treating CNS diseases.

Docking-based 3D-QSAR Studies of Phosphodiesterase 9A Inhibitors

Objective: We aim to provide new insight and scientific evidence for rational design and discovery of phosphodiesterase-9A (PDE9A) inhibitors with remarkable potency and weak side effect to treat CNS diseases such as Alzheimer’s disease. Keywords: PDE9A, 3D-QSAR, CoMFA, CoMSIA, molecular docking, inhibitors.

Dose-Dependent Pharmacokinetics and Metabolisms of Prolonged-Release Ketamine Tablets in Healthy Subjects

The anaesthetic effects of ketamine and its major metabolite norketamine (NK) are explained by NMDA receptor antagonism. There is ample new evidence, firstly, that metabolites of NK, as the 2R,6R/2S,6S-enantiomers of hydroxynorketamin (HNK), exert neuro-modulating effects by AMPA-receptor activation and, secondly, that the plasma levels of NK after oral dosing are higher than after intravenous administration. Therefore, we evaluated pharmacokinetics and metabolism of a newly developed prolonged-release ketamine dosage form to confirm its suitability for chromic treatment of CNS-diseases (e.g. depression) according to the new “Ketamine Metabolite Paradigm”. The dose-escalation study was performed in five consecutive periods (7 days wash-out) in 15 healthy subjects (5 females. 20-35 years, BMI 19.4-27.6 kg/m2). The racemic analytes were measured using validated LC-MS/MS methods. PR-K was safe and well tolerated.Tabled 15 mg i.v.10 mg p.o.20 mg p.o.40 mg p.o.80 mg p.o.AUC (ng×h/ml)52.3 ± 12.213.4 ± 13.333.5 ± 35.863.5 ± 42.6124 ± 72.9Cmax (ng/ml)29.9 ± 8.481.63 ± 1.333.70 ± 3.936.66 ± 4.2511.8 ± 6.56Tmax (h)-5.34 ± 1.185.70 ± 0.6495.87 ± 0.9156.27 ± 0.594*†F (%)-12.3 ± 10.715.3 ± 14.4*14.9 ± 8.94*14.6 ± 7.56*T½ (h)5.89 ± 2.614.96 ± 1.256.74 ± 2.02*7.21 ± 1.56#*7.68 ± 1.43#*†AUCNK/K1.79 ± 0.55721.6 ± 14.2#16.9 ± 8.58#*14.9 ± 8.50#*14.0 ± 6.50#*†AUCHNK/K0.334 ± 0.1287.33 ± 7.05#19.8 ± 16.4#*14.4 ± 8.99#*16.2 ± 7.93#*‡p<0.05 #vs. 5 mg i.v., *vs. 10 mg, †vs 20 mg, ‡vs. 40 mg p.o. (Wilcoxon) Open table in a new tab p<0.05 #vs. 5 mg i.v., *vs. 10 mg, †vs 20 mg, ‡vs. 40 mg p.o. (Wilcoxon) Prolonged-release ketamine undergoes dose-dependent “fist-pass” metabolism which generates substantially increased plasma exposure of downstream metabolites with potential neuro-modulating effects compared to ketamine after intravenous administration.

Use of LDL receptor-targeting peptide vectors for in vitro and in vivo cargo transport across the blood-brain barrier.

The blood-brain barrier (BBB) prevents the entry of many drugs into the brain and, thus, is a major obstacle in the treatment of CNS diseases. There is some evidence that the LDL receptor (LDLR) is expressed at the BBB and may participate in the transport of endogenous ligands from blood to brain, a process referred to as receptor-mediated transcytosis. We previously described a family of peptide vectors that were developed to target the LDLR. In the present study, in vitro BBB models that were derived from wild-type and LDLR-knockout animals (ldlr-/- ) were used to validate the specific LDLR-dependent transcytosis of LDL via a nondegradative route. We next showed that LDLR-targeting peptide vectors, whether in fusion or chemically conjugated to an Ab Fc fragment, promote binding to apical LDLR and transendothelial transfer of the Fc fragment across BBB monolayers via the same route as LDL. Finally, we demonstrated in vivo that LDLR significantly contributes to the brain uptake of vectorized Fc. We thus provide further evidence that LDLR is a relevant receptor for CNS drug delivery via receptor-mediated transcytosis and that the peptide vectors we developed have the potential to transport drugs, including proteins or Ab based, across the BBB.-Molino, Y., David, M., Varini, K., Jabès, F., Gaudin, N., Fortoul, A., Bakloul, K., Masse, M., Bernard, A., Drobecq, L., Lécorché, P., Temsamani, J., Jacquot, G., Khrestchatisky, M. Use of LDL receptor-targeting peptide vectors for in vitro and in vivo cargo transport across the blood-brain barrier.

Electroacupuncture Promotes Remyelination after Cuprizone Treatment by Enhancing Myelin Debris Clearance.

Promoting remyelination is crucial for patients with demyelinating diseases including multiple sclerosis. However, it is still a circuitous conundrum finding a practical remyelinating therapy. Electroacupuncture (EA), originating from traditional Chinese medicine (TCM), has been widely used to treat CNS diseases all over the world, but the role of EA in demyelinating diseases is barely known. In this study, we examined the remyelinating properties and mechanisms of EA in cuprizone-induced demyelinating model, a CNS demyelinating murine model of multiple sclerosis. By feeding C57BL/6 mice with chow containing 0.2% cuprizone for 5 weeks, we successfully induce demyelination as proved by weight change, beam test, pole test, histomorphology, and Western Blot. EA treatment significantly improves the neurobehavioral performance at week 7 (2 weeks after withdrawing cuprizone chow). RNA-seq and RT-PCR results reveal up-regulated expression of myelin-related genes, and the expression of myelin associated protein (MBP, CNPase, and O4) are also increased after EA treatment, indicating therapeutic effect of EA on cuprizone model. It is widely acknowledged that microglia exert phagocytic effect on degraded myelin debris and clear these detrimental debris, which is a necessary process for subsequent remyelination. We found the remyelinating effect of EA is associated with enhanced clearance of degraded myelin debris as detected by dMBP staining and red oil O staining. Our further studies suggest that more microglia assemble in demyelinating area (corpus callosum) during the process of EA treatment, and cells inside corpus callosum are mostly in a plump, ameboid, and phagocytic shape, quite different from the ramified cells outside corpus callosum. RNA-seq result also unravels that most genes relating to positive regulation of phagocytosis (GO:0050766) are up-regulated, indicating enhanced phagocytic process after EA treatment. During the process of myelin debris clearance, microglia tend to change their phenotype toward M2 phenotype. Thus, we also probed into the phenotype of microglia in our study. Immuno-staining results show increased expression of CD206 and Arg1, and the ratio of CD206/CD16/32 are also higher in EA group. In conclusion, these results demonstrate for the first time that EA enhances myelin debris removal from activated microglia after demyelination, and promotes remyelination.

Baicalein attenuates α-synuclein aggregation, inflammasome activation and autophagy in the MPP+-treated nigrostriatal dopaminergic system in vivo

Ethnopharmacological relevanceNeuroinflammation, oxidative stress, and protein aggregation form a vicious cycle in the pathophysiology of Parkinson's disease (PD); activated microglia is the main location of neuroinflammation. A Chinese medicine book, “Shanghan Lun”, known as the “Treatises on Cold damage Diseases” has suggested that Scutellaria baicalensis Georgi is effective in treating CNS diseases. The anti-inflammatory mechanisms of baicalein, a phenolic flavonoid in the dried root of Scutellaria baicalensis Georgi, remain to be explored. Aim of the studyThe neuroprotective mechanisms of baicalein involving α-synuclein aggregation, inflammasome activation, and programmed cell death were investigated in the nigrostriatal dopaminergic system of rat brain in vivo. Materials and methodsIntranigral infusion of 1-methyl-4-phenylpyridinium (MPP+, a Parkinsonian neurotoxin) was performed on anesthetized Sprague-Dawley rats. Baicalein was daily administered via intraperitoneal injection. Striatal dopamine levels were measured using high performance liquid chromatography coupled with electrochemical detection. Cellular signalings were measured by Western blot assay, immunofluorescent staining assay and enzyme-linked immunosorbent assay. ResultsSystemic administration of baicalein attenuated MPP+-induced reductions in striatal dopamine content and tyrosine hydroxylase (a biomarker of dopaminergic neurons) in the infused substantia nigra (SN). Furthermore, MPP+-induced elevations in α-synuclein aggregates (a pathological hallmark of PD), ED-1 (a biomarker of activated microglia), activated caspase-1 (a proinflammatory caspase), IL-1β and cathepsin B (a cysteine lysosomal protease) in the infused SN were attenuated in the baicalein-treated rats. Moreover, intense immunoreactivities of caspase 1 and cathepsin B were co-localized with that of ED-1 in the MPP+-infused SN. At the same time, baicalein inhibited MPP+-induced increases in active caspases 9 and 12 (biomarkers of apoptosis) as well as LC3-II levels (a biomarker of autophagy) in the rat nigrostriatal dopaminergic system. ConclusionOur in vivo study showed that baicalein possesses anti-inflammatory activities by inhibiting α-synuclein aggregation, inflammasome activation and cathepsin B production in the MPP+-infused SN. Moreover, baicalein is of therapeutic significance because it inhibits MPP+-induced apoptosis and autophagy in the nigrostriatal dopaminergic system of rat brain.

521. Platelets Transfusion New Role as Brain Therapeutics for Acute Neuronopathic Gaucher Disease

There has no effective treatment for neuronopathic Gaucher Disease (nGD) due to the difficulty of therapeutics to cross the blood-brain-barrier. Platelets are blood elements that contain cytoplasmic secretory vesicles containing proteins involved in hemostasis, inflammation and angiogenesis. We have recently shown that platelets/megakaryocytes could serve as efficient and protective depots for lysosomal enzyme generation and distribution. In this study the potential therapeutic benefits of platelet transfusion in treating neuronopathic GD (nGD) was evaluated using a murine model of acute nGD (4L;C), which resembles types 2 and 3 Gaucher disease. Platelets containing significant amounts of wild type acid ß-glucosidase enzyme (GCase) were isolated from GFP mice and transfused weekly into 4L;C mice for four times beginning at 21 days of age, resulting in an average 10-13% of donor-derived GFP+ platelets in circulation with half-life of 52 hr. Importantly, moderate platelet transfusion led to significantly increase of life-span in 4L;C mice from 47 days to 55 days with reduction of splenomegaly. The accumulation of glycosylsphingosin was significantly reduced in spleen, liver and brain. Moreover, the abnormal walk patterns with splaying of hindlimbs exhibited in 4L;C mice were improved significantly in platelet-treated mice, indicating amelioration of motor neuron dysfunction and hindlimb paresis. The improvement of short-term memory deficit in treated 4L;C mice was evidenced in repeated open-field test. Immunohistochemistry analysis showed that the elevated brain CD68+ signals, a marker for activated microglia cells, were normalized in cerebellum folium and middle brain regions, and partially corrected in the cortex, cerebellum DCN, brainstem, thalamus and spinal cord of treated 4L;C mice, indicating the reduction of pro-inflammation by platelet transfusion. Notably, RIPK3-positive signals within Purkinje neurons in cerebellum of nGD mice were significantly reduced, suggesting therapeutic benefit of platelet transfusion on neuronal necroptosis. This study reveals an under-appreciated, unexpected role for platelets in treating CNS diseases. These results provide proof of concept that platelet transfusion can achieve CNS benefits with brain substrate reduction and improvement in neurological function, as well as reducing pro-inflammation and neuronal necroptosis. The findings will open a door for new clinical approaches with platelet transfusion in treating nGD and potentially other brain diseases.

25. Intranasal Gene Delivery of AAV Iduronidase: An Effective and Non-Invasive Approach for Treatmentof CNS Disease in a Murine Model of MPS Type I

Mucopolysaccharidosis type I (MPS I) is a progressive, multisystemic, inherited metabolic disease caused by deficiency of alpha-L-iduronidase (IDUA). The most severe form of this disease (Hurler syndrome) results in death by age 10. Current treatments for this disease are ineffective in treating CNS disease due to the inability of lysosomal enzymes to traverse the blood-brain barrier. Our goal is to supplement current therapy, and treat CNS manifestations of the disease, by AAV-mediated gene delivery and expression of IDUA. We have taken a non-invasive and effective approach to the treatment of CNS disease by intranasal administration of an IDUA-encoding AAV9 vector. Adult IDUA-deficient mice were immunotolerized at birth with human iduronidase, to prevent anti-IDUA immune response, and at 3 months of age were infused intranasally with AAV9-IDUA vector. Animals sacrificed 3 months post-infusion exhibited IDUA enzyme activity levels that were 100-fold that of wild type in the olfactory bulb, with wild type levels of enzyme restored in all other parts of the brain. Neurocognitive testing using the Barnes maze demonstrated that treated IDUA-deficient mice were not different from normal control animals, while untreated IDUA-deficient mice exhibited a significant learning deficit. There was strong IDUA immunofluorescence staining observed in tissue sections of the nasal epithelium and olfactory bulb, but no staining was observed in other portions of the brain. This indicates that the widespread distribution of IDUA enzyme most likely was the result of enzyme diffusion from sites of transduction and IDUA expression in the olfactory bulb and the nasal epithelium into deeper areas of the brain. In order to increase access, delivery and vector distribution throughout the brain, IDUA-deficient animals were pretreated with intranasal infusions of an absorption enhancer. At different time points following pretreatment, animals were infused intranasally with AAV9 or AAVrh10 vector encoding IDUA. Animals were sacrificed at 2 months post-infusion, brains microdissected, and assayed for IDUA enzyme activity, clearance of glycosaminoglycans, and immunofluorescence staining for IDUA and GFP. This novel, non-invasive strategy for intranasal AAV9-IDUA administration could potentially be used to treat CNS manifestations of MPS I.

Unsuspected Intrinsic Property of Melanin to Dissociate Water Can Be Used for the Treatment of CNS Diseases

Retinal adhesion mechanisms in mammals are quite complex and multifactorial in nature. To date, these mechanisms are incompletely understood due to a variety of chemical, physical, and physiological forces impinging upon retinal tissue: retinal pigment epithelium, nearby tissues as sclera and vitreous, the subretinal space, and the highly complex interphotoreceptor matrix that fills subretinal space. The adhesion of the retina to the choroid, rather than anatomical, is a dynamic process, as the retina detaches a few minutes after life ceases. The adhesion mechanisms described in the literature, such as intraocular pressure and the oncotic pressure of the choroid that seems to push the retina towards the choroid, the delicate anatomical relationships between the rod and cone photoreceptors, the retinal pigment epithelium, the existence of a complex material called interphotoreceptor matrix, as well as other metabolic and structural factors, still cannot explain the remarkable features observed in the adhesion mechanisms between the photoreceptor layer and retinal pigment epithelium cells. The unexpected intrinsic property of melanin to absorb light energy and transform it into chemically based free energy can explain normal adhesion of the sensory retina to the pigment epithelium. In this article, we explore and highlight this explanation, which states that it is definitely able to provide a new treatment avenue against devastating neurodegenerative properties.

Glioma-targeted superparamagnetic iron oxide nanoparticles as drug-carrying vehicles for theranostic effects.

Multifunctional nanoparticles capable of the specific delivery of therapeutics to diseased cells and the real-time imaging of these sites have the potential to improve cancer treatment through personalized therapy. In this study, we have proposed a multifunctional nanoparticle that integrate magnetic targeting, drug-carrier functionality and real-time MRI imaging capabilities in one platform for the theranostic treatment of tumors. The multifunctional nanoparticle was designed with a superparamagnetic iron oxide core and a multifunctional shell composed of PEG/PEI/polysorbate 80 (Ps 80) and was used to encapsulate DOX. DOX-loaded multifunctional nanoparticles (DOX@Ps 80-SPIONs) with a Dh of 58.0 nm, a zeta potential of 28.0 mV, and a drug loading content of 29.3% presented superior superparamagnetic properties with a saturation magnetization (Ms) of 24.1 emu g(-1). The cellular uptake of DOX@Ps 80-SPIONs by C6 cells under a magnetic field was significantly enhanced over that of free DOX in solution, resulting in stronger in vitro cytotoxicity. The real-time therapeutic outcome of DOX@Ps 80-SPIONs was easily monitored by MRI. Furthermore, the negative contrast enhancement effect of the nanoparticles was confirmed in glioma-bearing rats. Prussian blue staining and ex vivo DOX fluorescence assays showed that the magnetic Ps 80-SPIONs and encapsulated DOX were delivered to gliomas by imposing external magnetic fields, indicating effective magnetic targeting. Due to magnetic targeting and Ps 80-mediated endocytosis, DOX@Ps 80-SPIONs in the presence of a magnetic field led to the complete suppression of glioma growth in vivo at 28 days after treatment. The therapeutic mechanism of DOX@Ps 80-SPIONs acted by inducing apoptosis through the caspase-3 pathway. Finally, DOX@Ps 80-SPIONs' safety at therapeutic dosage was verified using pathological HE assays of the heart, liver, spleen, lung and kidney. Multifunctional SPIONs could be used as potential carriers for the theranostic treatment of CNS diseases.

Rutin, A Natural Flavonoid Protects PC12 Cells Against Sodium Nitroprusside-Induced Neurotoxicity Through Activating PI3K/Akt/mTOR and ERK1/2 Pathway.

Free radicals induced neural damage is implicated in CNS diseases and rutin isolated form Lonicera japonica are reported to have neuroprotective activity. Previously, we confirmed that rutin exerted neuroprotective effect against sodium nitroprusside (SNP)-induced cell death in PC12 cells. However, the neuroprotective mechanism of rutin is still not fully uncovered. Here, we found that rutin significantly decreased SNP-induced reactive oxygen species in PC12 cells. Rutin reversed the declined GSH/GSSG ratio and mitochondrial membrane potential induced by SNP. Moreover, rutin activated both the protein Akt/mTOR and the extracellular signal-regulated kinase (ERK1/2) signaling pathways and the neuroprotective effects of rutin were blocked by either the specific PI3K inhibitor LY294002 or the MAPK pathway inhibitor PD98059. In summary, these results demonstrated that the neuroprotective effects of rutin might be through activating both the PI3K/Akt/mTOR and ERK1/2 signaling pathways. Our findings support that rutin may have therapeutic potential for the treatment of CNS diseases related to NO neurotoxicity.

Identification and electrophysiological evaluation of 2-methylbenzamide derivatives as Nav1.1 modulators.

Voltage-gated sodium channels (Nav) are crucial to the initiation and propagation of action potentials (APs) in electrically excitable cells, and during the past decades they have received considerable attention due to their therapeutic potential. Here, we report for the first time the synthesis and the electrophysiological evaluation of 16 ligands based on a 2-methylbenzamide scaffold that have been identified as Nav1.1 modulators. Among these compounds, N,N'-(1,3-phenylene)bis(2-methylbenzamide) (3a) has been selected and evaluated in ex-vivo experiments in order to estimate the activation impact of such a compound profile. It appears that 3a increases the Nav1.1 channel activity although its overall impact remains moderate. Altogether, our preliminary results provide new insights into the development of small molecule activators targeting specifically Nav1.1 channels to design potential drugs for treating CNS diseases.

Focused ultrasound-induced blood-brain barrier opening for non-viral, non-invasive, and targeted gene delivery

Focused ultrasound (FUS) exposure in the presence of microbubbles can temporally open the blood-brain barrier (BBB) and is an emerging technique for non-invasive brain therapeutic agent delivery. Given the potential to deliver large molecules into the CNS via this technique, we propose a reliable strategy to synergistically apply FUS-BBB opening for the non-invasive and targeted delivery of non-viral genes into the CNS for therapeutic purpose. In this study, we developed a gene-liposome system, in which the liposomes are designed to carry plasmid DNA (pDNA, containing luciferase reporter gene) to form a liposomal-plasmid DNA (LpDNA) complex. Pulsed FUS exposure was delivered to induce BBB opening (500-kHz, burst length=10ms, 1% duty cycle, PRF=1Hz). The longitudinal expression of luciferase was quantitated via an in vivo imaging system (IVIS). The reporter gene expression level was confirmed via immunoblotting, and histological staining was used to identify transfected cells via fluorescent microscopy. In a comparison of gene transduction efficiency, the LpDNA system showed better cell transduction than the pDNA system. With longitudinal observation of IVIS monitoring, animals with FUS treatment showed significant promotion of LpDNA release into the CNS and demonstrated enhanced expression of genes upon sonication with FUS-BBB opening, while both the luciferase and GDNF protein expression were successfully measured via Western blotting. The gene expression peak was observed at day 2, and the gene expression level was up to 5-fold higher than that in the untreated hemisphere (compared to a 1-fold increase in the direct-inject positive-control group). The transfection efficiency was also found to be LpDNA dose-dependent, where higher payloads of pDNA resulted in a higher transfection rate. Immunoblotting and histological staining confirmed the expression of reporter genes in glial cells as well as astrocytes. This study suggests that IV administration of LpDNA in combination with FUS-BBB opening can provide effective gene delivery and expression in the CNS, demonstrating the potential to achieve non-invasive and targeted gene delivery for treatment of CNS diseases.

Schwann cells induce Proliferation and Migration of Oligodendrocyte Precursor Cells Through Secretion of PDGF-AA and FGF-2.

Our previous study has showed that co-grafted Schwann cells (SCs) promote proliferation and migration of the grafted oligodendrocyte precursor cells (OPCs). However, how the co-grafted SCs affect OPCs has not been clarified. In the present study, we confirmed that SC-induced proliferation and migration of OPCs were mediated by SC-secreted factors using SC-conditioned medium (SCM). Then, we detected several candidate factors, PDGF-AA, FGF-2, and IGF-1, in SCs and SCM, and their receptors in OPCs. Finally, by using the selective inhibitors, the effects of these candidate factors on proliferation and migration of OPCs were examined. Our results showed that SCM-stimulated proliferation and migration of OPCs could be markedly decreased by both AG1295 (the inhibitor of PDGFR) and PD173074 (the inhibitor of FGFR). Together, our study suggests that SCs affect proliferation and migration of OPCs through secreting PDGF-AA and FGF-2. Identity of these molecules not only contributes to understand the mechanism of SC-induced proliferation and migration of OPCs but also provides possible target for treatment of CNS diseases.